initial user mode network support

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@733 c046a42c-6fe2-441c-8c8c-71466251a162

37 files changed, 12057 insertions, 0 deletions

diff --git a/slirp/bootp.c b/slirp/bootp.c
new file mode 100644
index 000000000..7e4b5bab0
--- /dev/null
+++ b/slirp/bootp.c
@@ -0,0 +1,212 @@
+/*
+ * QEMU BOOTP/DHCP server
+ * 
+ * Copyright (c) 2004 Fabrice Bellard
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include <slirp.h>
+
+/* XXX: only DHCP is supported */
+
+#define NB_ADDR 16
+
+#define START_ADDR 15
+
+#define LEASE_TIME (24 * 3600)
+
+typedef struct {
+    uint8_t allocated;
+} BOOTPClient;
+
+BOOTPClient bootp_clients[NB_ADDR];
+
+static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
+
+#ifdef DEBUG
+#define dprintf(fmt, args...) \
+if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## args); fflush(dfd); }
+#else
+#define dprintf(fmt, args...)
+#endif
+
+static BOOTPClient *get_new_addr(struct in_addr *paddr)
+{
+    BOOTPClient *bc;
+    int i;
+
+    for(i = 0; i < NB_ADDR; i++) {
+        if (!bootp_clients[i].allocated)
+            goto found;
+    }
+    return NULL;
+ found:
+    bc = &bootp_clients[i];
+    bc->allocated = 1;
+    paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR));
+    return bc;
+}
+
+static void dhcp_decode(const uint8_t *buf, int size,
+                        int *pmsg_type)
+{
+    const uint8_t *p, *p_end;
+    int len, tag;
+
+    *pmsg_type = 0;    
+
+    p = buf;
+    p_end = buf + size;
+    if (size < 5)
+        return;
+    if (memcmp(p, rfc1533_cookie, 4) != 0)
+        return;
+    p += 4;
+    while (p < p_end) {
+        tag = p[0];
+        if (tag == RFC1533_PAD) {
+            p++; 
+        } else if (tag == RFC1533_END) {
+            break;
+        } else {
+            p++;
+            if (p >= p_end)
+                break;
+            len = *p++;
+            dprintf("dhcp: tag=0x%02x len=%d\n", tag, len);
+
+            switch(tag) {
+            case RFC2132_MSG_TYPE:
+                if (len >= 1)
+                    *pmsg_type = p[0];
+                break;
+            default:
+                break;
+            }
+            p += len;
+        }
+    }
+}
+
+static void bootp_reply(struct bootp_t *bp)
+{
+    BOOTPClient *bc;
+    struct mbuf *m;
+    struct bootp_t *rbp;
+    struct sockaddr_in saddr, daddr;
+    struct in_addr dns_addr;
+    int dhcp_msg_type, val;
+    uint8_t *q;
+
+    /* extract exact DHCP msg type */
+    dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type);
+    dprintf("bootp packet op=%d msgtype=%d\n", bp->bp_op, dhcp_msg_type);
+    
+    if (dhcp_msg_type != DHCPDISCOVER && 
+        dhcp_msg_type != DHCPREQUEST)
+        return;
+    /* XXX: this is a hack to get the client mac address */
+    memcpy(client_ethaddr, bp->bp_hwaddr, 6);
+    
+    if ((m = m_get()) == NULL)
+        return;
+    m->m_data += if_maxlinkhdr;
+    rbp = (struct bootp_t *)m->m_data;
+    m->m_data += sizeof(struct udpiphdr);
+    memset(rbp, 0, sizeof(struct bootp_t));
+
+    bc = get_new_addr(&daddr.sin_addr);
+    if (!bc) {
+        dprintf("no address left\n");
+        return;
+    }
+    dprintf("offered addr=%08x\n", ntohl(daddr.sin_addr.s_addr));
+
+    saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS);
+    saddr.sin_port = htons(BOOTP_SERVER);
+
+    daddr.sin_port = htons(BOOTP_CLIENT);
+
+    rbp->bp_op = BOOTP_REPLY;
+    rbp->bp_xid = bp->bp_xid;
+    rbp->bp_htype = 1;
+    rbp->bp_hlen = 6;
+    memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
+
+    rbp->bp_yiaddr = daddr.sin_addr; /* IP address */
+
+    q = rbp->bp_vend;
+    memcpy(q, rfc1533_cookie, 4);
+    q += 4;
+
+    if (dhcp_msg_type == DHCPDISCOVER) {
+        *q++ = RFC2132_MSG_TYPE;
+        *q++ = 1;
+        *q++ = DHCPOFFER;
+    } else if (dhcp_msg_type == DHCPREQUEST) {
+        *q++ = RFC2132_MSG_TYPE;
+        *q++ = 1;
+        *q++ = DHCPACK;
+    }
+        
+    if (dhcp_msg_type == DHCPDISCOVER ||
+        dhcp_msg_type == DHCPREQUEST) {
+        *q++ = RFC2132_SRV_ID;
+        *q++ = 4;
+        memcpy(q, &saddr.sin_addr, 4);
+        q += 4;
+
+        *q++ = RFC1533_NETMASK;
+        *q++ = 4;
+        *q++ = 0xff;
+        *q++ = 0xff;
+        *q++ = 0xff;
+        *q++ = 0x00;
+        
+        *q++ = RFC1533_GATEWAY;
+        *q++ = 4;
+        memcpy(q, &saddr.sin_addr, 4);
+        q += 4;
+        
+        *q++ = RFC1533_DNS;
+        *q++ = 4;
+        dns_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_DNS);
+        memcpy(q, &dns_addr, 4);
+        q += 4;
+
+        *q++ = RFC2132_LEASE_TIME;
+        *q++ = 4;
+        val = htonl(LEASE_TIME);
+        memcpy(q, &val, 4);
+        q += 4;
+    }
+    *q++ = RFC1533_END;
+    
+    m->m_len = sizeof(struct bootp_t);
+    udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
+}
+
+void bootp_input(struct mbuf *m)
+{
+    struct bootp_t *bp = (struct bootp_t *)m->m_data;
+
+    if (bp->bp_op == BOOTP_REQUEST) {
+        bootp_reply(bp);
+    }
+}
diff --git a/slirp/bootp.h b/slirp/bootp.h
new file mode 100644
index 000000000..d3b2baa04
--- /dev/null
+++ b/slirp/bootp.h
@@ -0,0 +1,113 @@
+/* bootp/dhcp defines */
+
+#define BOOTP_SERVER	67
+#define BOOTP_CLIENT	68
+
+#define BOOTP_REQUEST	1
+#define BOOTP_REPLY	2
+
+#define RFC1533_COOKIE		99, 130, 83, 99
+#define RFC1533_PAD		0
+#define RFC1533_NETMASK		1
+#define RFC1533_TIMEOFFSET	2
+#define RFC1533_GATEWAY		3
+#define RFC1533_TIMESERVER	4
+#define RFC1533_IEN116NS	5
+#define RFC1533_DNS		6
+#define RFC1533_LOGSERVER	7
+#define RFC1533_COOKIESERVER	8
+#define RFC1533_LPRSERVER	9
+#define RFC1533_IMPRESSSERVER	10
+#define RFC1533_RESOURCESERVER	11
+#define RFC1533_HOSTNAME	12
+#define RFC1533_BOOTFILESIZE	13
+#define RFC1533_MERITDUMPFILE	14
+#define RFC1533_DOMAINNAME	15
+#define RFC1533_SWAPSERVER	16
+#define RFC1533_ROOTPATH	17
+#define RFC1533_EXTENSIONPATH	18
+#define RFC1533_IPFORWARDING	19
+#define RFC1533_IPSOURCEROUTING	20
+#define RFC1533_IPPOLICYFILTER	21
+#define RFC1533_IPMAXREASSEMBLY	22
+#define RFC1533_IPTTL		23
+#define RFC1533_IPMTU		24
+#define RFC1533_IPMTUPLATEAU	25
+#define RFC1533_INTMTU		26
+#define RFC1533_INTLOCALSUBNETS	27
+#define RFC1533_INTBROADCAST	28
+#define RFC1533_INTICMPDISCOVER	29
+#define RFC1533_INTICMPRESPOND	30
+#define RFC1533_INTROUTEDISCOVER 31
+#define RFC1533_INTROUTESOLICIT	32
+#define RFC1533_INTSTATICROUTES	33
+#define RFC1533_LLTRAILERENCAP	34
+#define RFC1533_LLARPCACHETMO	35
+#define RFC1533_LLETHERNETENCAP	36
+#define RFC1533_TCPTTL		37
+#define RFC1533_TCPKEEPALIVETMO	38
+#define RFC1533_TCPKEEPALIVEGB	39
+#define RFC1533_NISDOMAIN	40
+#define RFC1533_NISSERVER	41
+#define RFC1533_NTPSERVER	42
+#define RFC1533_VENDOR		43
+#define RFC1533_NBNS		44
+#define RFC1533_NBDD		45
+#define RFC1533_NBNT		46
+#define RFC1533_NBSCOPE		47
+#define RFC1533_XFS		48
+#define RFC1533_XDM		49
+
+#define RFC2132_REQ_ADDR	50
+#define RFC2132_LEASE_TIME      51
+#define RFC2132_MSG_TYPE	53
+#define RFC2132_SRV_ID		54
+#define RFC2132_PARAM_LIST	55
+#define RFC2132_MAX_SIZE	57
+#define RFC2132_RENEWAL_TIME    58
+#define RFC2132_REBIND_TIME     59
+
+#define DHCPDISCOVER		1
+#define DHCPOFFER		2
+#define DHCPREQUEST		3
+#define DHCPACK			5
+
+#define RFC1533_VENDOR_MAJOR	0
+#define RFC1533_VENDOR_MINOR	0
+
+#define RFC1533_VENDOR_MAGIC	128
+#define RFC1533_VENDOR_ADDPARM	129
+#define	RFC1533_VENDOR_ETHDEV	130
+#define RFC1533_VENDOR_HOWTO    132
+#define RFC1533_VENDOR_MNUOPTS	160
+#define RFC1533_VENDOR_SELECTION 176
+#define RFC1533_VENDOR_MOTD	184
+#define RFC1533_VENDOR_NUMOFMOTD 8
+#define RFC1533_VENDOR_IMG	192
+#define RFC1533_VENDOR_NUMOFIMG	16
+
+#define RFC1533_END		255
+#define BOOTP_VENDOR_LEN	64
+#define DHCP_OPT_LEN		312
+
+struct bootp_t {
+    struct ip ip;
+    struct udphdr udp;
+    uint8_t bp_op;
+    uint8_t bp_htype;
+    uint8_t bp_hlen;
+    uint8_t bp_hops;
+    unsigned long bp_xid;
+    unsigned short bp_secs;
+    unsigned short unused;
+    struct in_addr bp_ciaddr;
+    struct in_addr bp_yiaddr;
+    struct in_addr bp_siaddr;
+    struct in_addr bp_giaddr;
+    uint8_t bp_hwaddr[16];
+    uint8_t bp_sname[64];
+    uint8_t bp_file[128];
+    uint8_t bp_vend[DHCP_OPT_LEN];
+};
+
+void bootp_input(struct mbuf *m);
diff --git a/slirp/cksum.c b/slirp/cksum.c
new file mode 100644
index 000000000..f8f7512b6
--- /dev/null
+++ b/slirp/cksum.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 1988, 1992, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)in_cksum.c	8.1 (Berkeley) 6/10/93
+ * in_cksum.c,v 1.2 1994/08/02 07:48:16 davidg Exp
+ */
+
+#include <slirp.h>
+
+/*
+ * Checksum routine for Internet Protocol family headers (Portable Version).
+ *
+ * This routine is very heavily used in the network
+ * code and should be modified for each CPU to be as fast as possible.
+ * 
+ * XXX Since we will never span more than 1 mbuf, we can optimise this
+ */
+
+#define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)
+#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
+
+int cksum(struct mbuf *m, int len)
+{
+	register u_int16_t *w;
+	register int sum = 0;
+	register int mlen = 0;
+	int byte_swapped = 0;
+
+	union {
+		u_int8_t	c[2];
+		u_int16_t	s;
+	} s_util;
+	union {
+		u_int16_t s[2];
+		u_int32_t l;
+	} l_util;
+	
+	if (m->m_len == 0)
+	   goto cont;
+	w = mtod(m, u_int16_t *);
+	
+	mlen = m->m_len;
+	
+	if (len < mlen)
+	   mlen = len;
+	len -= mlen;
+	/*
+	 * Force to even boundary.
+	 */
+	if ((1 & (long) w) && (mlen > 0)) {
+		REDUCE;
+		sum <<= 8;
+		s_util.c[0] = *(u_int8_t *)w;
+		w = (u_int16_t *)((int8_t *)w + 1);
+		mlen--;
+		byte_swapped = 1;
+	}
+	/*
+	 * Unroll the loop to make overhead from
+	 * branches &c small.
+	 */
+	while ((mlen -= 32) >= 0) {
+		sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
+		sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
+		sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
+		sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
+		w += 16;
+	}
+	mlen += 32;
+	while ((mlen -= 8) >= 0) {
+		sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
+		w += 4;
+	}
+	mlen += 8;
+	if (mlen == 0 && byte_swapped == 0)
+	   goto cont;
+	REDUCE;
+	while ((mlen -= 2) >= 0) {
+		sum += *w++;
+	}
+	
+	if (byte_swapped) {
+		REDUCE;
+		sum <<= 8;
+		byte_swapped = 0;
+		if (mlen == -1) {
+			s_util.c[1] = *(u_int8_t *)w;
+			sum += s_util.s;
+			mlen = 0;
+		} else
+		   
+		   mlen = -1;
+	} else if (mlen == -1)
+	   s_util.c[0] = *(u_int8_t *)w;
+	
+cont:
+#ifdef DEBUG
+	if (len) {
+		DEBUG_ERROR((dfd, "cksum: out of data\n"));
+		DEBUG_ERROR((dfd, " len = %d\n", len));
+	}
+#endif
+	if (mlen == -1) {
+		/* The last mbuf has odd # of bytes. Follow the
+		 standard (the odd byte may be shifted left by 8 bits
+			   or not as determined by endian-ness of the machine) */
+		s_util.c[1] = 0;
+		sum += s_util.s;
+	}
+	REDUCE;
+	return (~sum & 0xffff);
+}
diff --git a/slirp/ctl.h b/slirp/ctl.h
new file mode 100644
index 000000000..4a8576dc1
--- /dev/null
+++ b/slirp/ctl.h
@@ -0,0 +1,7 @@
+#define CTL_CMD		0
+#define CTL_EXEC	1
+#define CTL_ALIAS	2
+#define CTL_DNS		3
+
+#define CTL_SPECIAL	"10.0.2.0"
+#define CTL_LOCAL	"10.0.2.15"
diff --git a/slirp/debug.c b/slirp/debug.c
new file mode 100644
index 000000000..d3d8c5796
--- /dev/null
+++ b/slirp/debug.c
@@ -0,0 +1,376 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * Portions copyright (c) 2000 Kelly Price.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+FILE *dfd = NULL;
+#ifdef DEBUG
+int dostats = 1;
+#else
+int dostats = 0;
+#endif
+int slirp_debug = 0;
+
+extern char *strerror _P((int));
+
+/* Carry over one item from main.c so that the tty's restored. 
+ * Only done when the tty being used is /dev/tty --RedWolf */
+extern struct termios slirp_tty_settings;
+extern int slirp_tty_restore;
+
+
+void
+debug_init(file, dbg)
+	char *file;
+	int dbg;
+{
+	/* Close the old debugging file */
+	if (dfd)
+	   fclose(dfd);
+	
+	dfd = fopen(file,"w");
+	if (dfd != NULL) {
+#if 0
+		fprintf(dfd,"Slirp %s - Debugging Started.\n", SLIRP_VERSION);
+#endif
+		fprintf(dfd,"Debugging Started level %i.\r\n",dbg);
+		fflush(dfd);
+		slirp_debug = dbg;
+	} else {
+		lprint("Error: Debugging file \"%s\" could not be opened: %s\r\n",
+			file, strerror(errno));
+	}
+}
+
+/*
+ * Dump a packet in the same format as tcpdump -x
+ */
+#ifdef DEBUG
+void
+dump_packet(dat, n)
+	void *dat;
+	int n;
+{
+	u_char *pptr = (u_char *)dat;
+	int j,k;
+	
+	n /= 16;
+	n++;
+	DEBUG_MISC((dfd, "PACKET DUMPED: \n"));
+	for(j = 0; j < n; j++) {
+		for(k = 0; k < 6; k++)
+			DEBUG_MISC((dfd, "%02x ", *pptr++));
+		DEBUG_MISC((dfd, "\n"));
+		fflush(dfd);
+	}
+}
+#endif
+
+#if 0
+/*
+ * Statistic routines
+ * 
+ * These will print statistics to the screen, the debug file (dfd), or
+ * a buffer, depending on "type", so that the stats can be sent over
+ * the link as well.
+ */
+
+void
+ttystats(ttyp)
+	struct ttys *ttyp;
+{
+	struct slirp_ifstats *is = &ttyp->ifstats;
+	char buff[512];
+	
+	lprint(" \r\n");
+	
+	if (if_comp & IF_COMPRESS)
+	   strcpy(buff, "on");
+	else if (if_comp & IF_NOCOMPRESS)
+	   strcpy(buff, "off");
+	else
+	   strcpy(buff, "off (for now)");
+	lprint("Unit %d:\r\n", ttyp->unit);
+	lprint("  using %s encapsulation (VJ compression is %s)\r\n", (
+#ifdef USE_PPP
+	       ttyp->proto==PROTO_PPP?"PPP":
+#endif
+	       "SLIP"), buff);
+	lprint("  %d baudrate\r\n", ttyp->baud);
+	lprint("  interface is %s\r\n", ttyp->up?"up":"down");
+	lprint("  using fd %d, guardian pid is %d\r\n", ttyp->fd, ttyp->pid);
+#ifndef FULL_BOLT
+	lprint("  towrite is %d bytes\r\n", ttyp->towrite);
+#endif
+	if (ttyp->zeros)
+	   lprint("  %d zeros have been typed\r\n", ttyp->zeros);
+	else if (ttyp->ones)
+	   lprint("  %d ones have been typed\r\n", ttyp->ones);
+	lprint("Interface stats:\r\n");
+	lprint("  %6d output packets sent (%d bytes)\r\n", is->out_pkts, is->out_bytes);
+	lprint("  %6d output packets dropped (%d bytes)\r\n", is->out_errpkts, is->out_errbytes);
+	lprint("  %6d input packets received (%d bytes)\r\n", is->in_pkts, is->in_bytes);
+	lprint("  %6d input packets dropped (%d bytes)\r\n", is->in_errpkts, is->in_errbytes);
+	lprint("  %6d bad input packets\r\n", is->in_mbad);
+}
+
+void
+allttystats()
+{
+	struct ttys *ttyp;
+	
+	for (ttyp = ttys; ttyp; ttyp = ttyp->next)
+	   ttystats(ttyp);
+}
+#endif
+
+void
+ipstats()
+{
+	lprint(" \r\n");	
+
+	lprint("IP stats:\r\n");
+	lprint("  %6d total packets received (%d were unaligned)\r\n",
+			ipstat.ips_total, ipstat.ips_unaligned);
+	lprint("  %6d with incorrect version\r\n", ipstat.ips_badvers);
+	lprint("  %6d with bad header checksum\r\n", ipstat.ips_badsum);
+	lprint("  %6d with length too short (len < sizeof(iphdr))\r\n", ipstat.ips_tooshort);
+	lprint("  %6d with length too small (len < ip->len)\r\n", ipstat.ips_toosmall);
+	lprint("  %6d with bad header length\r\n", ipstat.ips_badhlen);
+	lprint("  %6d with bad packet length\r\n", ipstat.ips_badlen);
+	lprint("  %6d fragments received\r\n", ipstat.ips_fragments);
+	lprint("  %6d fragments dropped\r\n", ipstat.ips_fragdropped);
+	lprint("  %6d fragments timed out\r\n", ipstat.ips_fragtimeout);
+	lprint("  %6d packets reassembled ok\r\n", ipstat.ips_reassembled);
+	lprint("  %6d outgoing packets fragmented\r\n", ipstat.ips_fragmented);
+	lprint("  %6d total outgoing fragments\r\n", ipstat.ips_ofragments);
+	lprint("  %6d with bad protocol field\r\n", ipstat.ips_noproto);
+	lprint("  %6d total packets delivered\r\n", ipstat.ips_delivered);
+}
+
+#if 0
+void
+vjstats()
+{
+	lprint(" \r\n");
+	
+	lprint("VJ compression stats:\r\n");
+	
+	lprint("  %6d outbound packets (%d compressed)\r\n",
+	       comp_s.sls_packets, comp_s.sls_compressed);
+	lprint("  %6d searches for connection stats (%d misses)\r\n",
+	       comp_s.sls_searches, comp_s.sls_misses);
+	lprint("  %6d inbound uncompressed packets\r\n", comp_s.sls_uncompressedin);
+	lprint("  %6d inbound compressed packets\r\n", comp_s.sls_compressedin);
+	lprint("  %6d inbound unknown type packets\r\n", comp_s.sls_errorin);
+	lprint("  %6d inbound packets tossed due to error\r\n", comp_s.sls_tossed);
+}
+#endif
+
+void
+tcpstats()
+{
+	lprint(" \r\n");
+
+	lprint("TCP stats:\r\n");
+	
+	lprint("  %6d packets sent\r\n", tcpstat.tcps_sndtotal);
+	lprint("          %6d data packets (%d bytes)\r\n",
+			tcpstat.tcps_sndpack, tcpstat.tcps_sndbyte);
+	lprint("          %6d data packets retransmitted (%d bytes)\r\n",
+			tcpstat.tcps_sndrexmitpack, tcpstat.tcps_sndrexmitbyte);
+	lprint("          %6d ack-only packets (%d delayed)\r\n",
+			tcpstat.tcps_sndacks, tcpstat.tcps_delack);
+	lprint("          %6d URG only packets\r\n", tcpstat.tcps_sndurg);
+	lprint("          %6d window probe packets\r\n", tcpstat.tcps_sndprobe);
+	lprint("          %6d window update packets\r\n", tcpstat.tcps_sndwinup);
+	lprint("          %6d control (SYN/FIN/RST) packets\r\n", tcpstat.tcps_sndctrl);
+	lprint("          %6d times tcp_output did nothing\r\n", tcpstat.tcps_didnuttin);
+	
+	lprint("  %6d packets received\r\n", tcpstat.tcps_rcvtotal);       
+	lprint("          %6d acks (for %d bytes)\r\n",
+			tcpstat.tcps_rcvackpack, tcpstat.tcps_rcvackbyte);
+	lprint("          %6d duplicate acks\r\n", tcpstat.tcps_rcvdupack);
+	lprint("          %6d acks for unsent data\r\n", tcpstat.tcps_rcvacktoomuch);
+	lprint("          %6d packets received in sequence (%d bytes)\r\n",
+			tcpstat.tcps_rcvpack, tcpstat.tcps_rcvbyte);
+        lprint("          %6d completely duplicate packets (%d bytes)\r\n",
+			tcpstat.tcps_rcvduppack, tcpstat.tcps_rcvdupbyte);
+	
+	lprint("          %6d packets with some duplicate data (%d bytes duped)\r\n",
+			tcpstat.tcps_rcvpartduppack, tcpstat.tcps_rcvpartdupbyte);
+	lprint("          %6d out-of-order packets (%d bytes)\r\n",
+			tcpstat.tcps_rcvoopack, tcpstat.tcps_rcvoobyte);
+	lprint("          %6d packets of data after window (%d bytes)\r\n",
+			tcpstat.tcps_rcvpackafterwin, tcpstat.tcps_rcvbyteafterwin);
+	lprint("          %6d window probes\r\n", tcpstat.tcps_rcvwinprobe);
+	lprint("          %6d window update packets\r\n", tcpstat.tcps_rcvwinupd);
+	lprint("          %6d packets received after close\r\n", tcpstat.tcps_rcvafterclose);
+	lprint("          %6d discarded for bad checksums\r\n", tcpstat.tcps_rcvbadsum);
+	lprint("          %6d discarded for bad header offset fields\r\n",
+			tcpstat.tcps_rcvbadoff);
+	
+	lprint("  %6d connection requests\r\n", tcpstat.tcps_connattempt);
+	lprint("  %6d connection accepts\r\n", tcpstat.tcps_accepts);
+	lprint("  %6d connections established (including accepts)\r\n", tcpstat.tcps_connects);
+	lprint("  %6d connections closed (including %d drop)\r\n",
+			tcpstat.tcps_closed, tcpstat.tcps_drops);
+	lprint("  %6d embryonic connections dropped\r\n", tcpstat.tcps_conndrops);
+	lprint("  %6d segments we tried to get rtt (%d succeeded)\r\n",
+			tcpstat.tcps_segstimed, tcpstat.tcps_rttupdated);
+	lprint("  %6d retransmit timeouts\r\n", tcpstat.tcps_rexmttimeo);
+	lprint("          %6d connections dropped by rxmt timeout\r\n",
+			tcpstat.tcps_timeoutdrop);
+	lprint("  %6d persist timeouts\r\n", tcpstat.tcps_persisttimeo);
+	lprint("  %6d keepalive timeouts\r\n", tcpstat.tcps_keeptimeo);
+	lprint("          %6d keepalive probes sent\r\n", tcpstat.tcps_keepprobe);
+	lprint("          %6d connections dropped by keepalive\r\n", tcpstat.tcps_keepdrops);
+	lprint("  %6d correct ACK header predictions\r\n", tcpstat.tcps_predack);
+	lprint("  %6d correct data packet header predictions\n", tcpstat.tcps_preddat);
+	lprint("  %6d TCP cache misses\r\n", tcpstat.tcps_socachemiss);
+	
+	
+/*	lprint("    Packets received too short:		%d\r\n", tcpstat.tcps_rcvshort); */
+/*	lprint("    Segments dropped due to PAWS:	%d\r\n", tcpstat.tcps_pawsdrop); */
+
+}
+
+void
+udpstats()
+{
+        lprint(" \r\n");
+
+	lprint("UDP stats:\r\n");
+	lprint("  %6d datagrams received\r\n", udpstat.udps_ipackets);
+	lprint("  %6d with packets shorter than header\r\n", udpstat.udps_hdrops);
+	lprint("  %6d with bad checksums\r\n", udpstat.udps_badsum);
+	lprint("  %6d with data length larger than packet\r\n", udpstat.udps_badlen);
+	lprint("  %6d UDP socket cache misses\r\n", udpstat.udpps_pcbcachemiss);
+	lprint("  %6d datagrams sent\r\n", udpstat.udps_opackets);
+}
+
+void
+icmpstats()
+{
+	lprint(" \r\n");
+	lprint("ICMP stats:\r\n");
+	lprint("  %6d ICMP packets received\r\n", icmpstat.icps_received);
+	lprint("  %6d were too short\r\n", icmpstat.icps_tooshort);
+	lprint("  %6d with bad checksums\r\n", icmpstat.icps_checksum);
+	lprint("  %6d with type not supported\r\n", icmpstat.icps_notsupp);
+	lprint("  %6d with bad type feilds\r\n", icmpstat.icps_badtype);
+	lprint("  %6d ICMP packets sent in reply\r\n", icmpstat.icps_reflect);
+}
+
+void
+mbufstats()
+{
+	struct mbuf *m;
+	int i;
+	
+        lprint(" \r\n");
+	
+	lprint("Mbuf stats:\r\n");
+
+	lprint("  %6d mbufs allocated (%d max)\r\n", mbuf_alloced, mbuf_max);
+	
+	i = 0;
+	for (m = m_freelist.m_next; m != &m_freelist; m = m->m_next)
+		i++;
+	lprint("  %6d mbufs on free list\r\n",  i);
+	
+	i = 0;
+	for (m = m_usedlist.m_next; m != &m_usedlist; m = m->m_next)
+		i++;
+	lprint("  %6d mbufs on used list\r\n",  i);
+        lprint("  %6d mbufs queued as packets\r\n\r\n", if_queued);
+}
+
+void
+sockstats()
+{
+	char buff[256];
+	int n;
+	struct socket *so;
+
+        lprint(" \r\n");
+	
+	lprint(
+	   "Proto[state]     Sock     Local Address, Port  Remote Address, Port RecvQ SendQ\r\n");
+			
+	for (so = tcb.so_next; so != &tcb; so = so->so_next) {
+		
+		n = sprintf(buff, "tcp[%s]", so->so_tcpcb?tcpstates[so->so_tcpcb->t_state]:"NONE");
+		while (n < 17)
+		   buff[n++] = ' ';
+		buff[17] = 0;
+		lprint("%s %3d   %15s %5d ",
+				buff, so->s,
+				inet_ntoa(so->so_laddr), ntohs(so->so_lport));
+		lprint("%15s %5d %5d %5d\r\n",
+				inet_ntoa(so->so_faddr), ntohs(so->so_fport),
+				so->so_rcv.sb_cc, so->so_snd.sb_cc);
+	}
+		   
+	for (so = udb.so_next; so != &udb; so = so->so_next) {
+		
+		n = sprintf(buff, "udp[%d sec]", (so->so_expire - curtime) / 1000);
+		while (n < 17)
+		   buff[n++] = ' ';
+		buff[17] = 0;
+		lprint("%s %3d  %15s %5d  ",
+				buff, so->s,
+				inet_ntoa(so->so_laddr), ntohs(so->so_lport));
+		lprint("%15s %5d %5d %5d\r\n",
+				inet_ntoa(so->so_faddr), ntohs(so->so_fport),
+				so->so_rcv.sb_cc, so->so_snd.sb_cc);
+	}
+}
+
+#if 0
+void
+slirp_exit(exit_status)
+	int exit_status;
+{
+	struct ttys *ttyp;
+	
+	DEBUG_CALL("slirp_exit");
+	DEBUG_ARG("exit_status = %d", exit_status);
+
+	if (dostats) {
+		lprint_print = (int (*) _P((void *, const char *, va_list)))vfprintf;
+		if (!dfd)
+		   debug_init("slirp_stats", 0xf);
+		lprint_arg = (char **)&dfd;
+		
+		ipstats();
+		tcpstats();
+		udpstats();
+		icmpstats();
+		mbufstats();
+		sockstats();
+		allttystats();
+		vjstats();
+	}
+	
+	for (ttyp = ttys; ttyp; ttyp = ttyp->next)
+	   tty_detached(ttyp, 1);
+	
+	if (slirp_forked) {
+		/* Menendez time */
+		if (kill(getppid(), SIGQUIT) < 0)
+			lprint("Couldn't kill parent process %ld!\n",
+			    (long) getppid());
+    	}
+	
+	/* Restore the terminal if we gotta */
+	if(slirp_tty_restore)
+	  tcsetattr(0,TCSANOW, &slirp_tty_settings);  /* NOW DAMMIT! */
+	exit(exit_status);
+}
+#endif
diff --git a/slirp/debug.h b/slirp/debug.h
new file mode 100644
index 000000000..6e8444dab
--- /dev/null
+++ b/slirp/debug.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#define PRN_STDERR	1
+#define PRN_SPRINTF	2
+
+extern FILE *dfd;
+extern FILE *lfd;
+extern int dostats;
+extern int slirp_debug;
+
+#define DBG_CALL 0x1
+#define DBG_MISC 0x2
+#define DBG_ERROR 0x4
+#define DEBUG_DEFAULT DBG_CALL|DBG_MISC|DBG_ERROR
+
+#ifdef DEBUG
+#define DEBUG_CALL(x) if (slirp_debug & DBG_CALL) { fprintf(dfd, "%s...\n", x); fflush(dfd); }
+#define DEBUG_ARG(x, y) if (slirp_debug & DBG_CALL) { fputc(' ', dfd); fprintf(dfd, x, y); fputc('\n', dfd); fflush(dfd); }
+#define DEBUG_ARGS(x) if (slirp_debug & DBG_CALL) { fprintf x ; fflush(dfd); }
+#define DEBUG_MISC(x) if (slirp_debug & DBG_MISC) { fprintf x ; fflush(dfd); }
+#define DEBUG_ERROR(x) if (slirp_debug & DBG_ERROR) {fprintf x ; fflush(dfd); }
+
+
+#else
+
+#define DEBUG_CALL(x)
+#define DEBUG_ARG(x, y)
+#define DEBUG_ARGS(x)
+#define DEBUG_MISC(x)
+#define DEBUG_ERROR(x)
+
+#endif
+
+void debug_init _P((char *, int));
+//void ttystats _P((struct ttys *));
+void allttystats _P((void));
+void ipstats _P((void));
+void vjstats _P((void));
+void tcpstats _P((void));
+void udpstats _P((void));
+void icmpstats _P((void));
+void mbufstats _P((void));
+void sockstats _P((void));
+void slirp_exit _P((int));
+
diff --git a/slirp/icmp_var.h b/slirp/icmp_var.h
new file mode 100644
index 000000000..03fc8c3ac
--- /dev/null
+++ b/slirp/icmp_var.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)icmp_var.h	8.1 (Berkeley) 6/10/93
+ * icmp_var.h,v 1.4 1995/02/16 00:27:40 wollman Exp
+ */
+
+#ifndef _NETINET_ICMP_VAR_H_
+#define _NETINET_ICMP_VAR_H_
+
+/*
+ * Variables related to this implementation
+ * of the internet control message protocol.
+ */
+struct icmpstat {
+/* statistics related to input messages processed */
+	u_long  icps_received;		/* #ICMP packets received */
+	u_long	icps_tooshort;		/* packet < ICMP_MINLEN */
+	u_long	icps_checksum;		/* bad checksum */
+	u_long	icps_notsupp;		/* #ICMP packets not supported */
+	u_long  icps_badtype;		/* #with bad type feild */
+	u_long	icps_reflect;		/* number of responses */
+};
+
+/*
+ * Names for ICMP sysctl objects
+ */
+#define	ICMPCTL_MASKREPL	1	/* allow replies to netmask requests */
+#define	ICMPCTL_STATS		2	/* statistics (read-only) */
+#define ICMPCTL_MAXID		3
+
+#define ICMPCTL_NAMES { \
+	{ 0, 0 }, \
+	{ "maskrepl", CTLTYPE_INT }, \
+	{ "stats", CTLTYPE_STRUCT }, \
+}
+
+extern struct icmpstat icmpstat;
+
+#endif
diff --git a/slirp/if.c b/slirp/if.c
new file mode 100644
index 000000000..282b674c5
--- /dev/null
+++ b/slirp/if.c
@@ -0,0 +1,320 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+int if_mtu, if_mru;
+int if_comp;
+int if_maxlinkhdr;
+int     if_queued = 0;                  /* Number of packets queued so far */
+int     if_thresh = 10;                 /* Number of packets queued before we start sending
+					 * (to prevent allocing too many mbufs) */
+
+struct  mbuf if_fastq;                  /* fast queue (for interactive data) */
+struct  mbuf if_batchq;                 /* queue for non-interactive data */
+struct	mbuf *next_m;			/* Pointer to next mbuf to output */
+
+#define ifs_init(ifm) ((ifm)->ifs_next = (ifm)->ifs_prev = (ifm))
+
+void
+ifs_insque(ifm, ifmhead)
+	struct mbuf *ifm, *ifmhead;
+{
+	ifm->ifs_next = ifmhead->ifs_next;
+	ifmhead->ifs_next = ifm;
+	ifm->ifs_prev = ifmhead;
+	ifm->ifs_next->ifs_prev = ifm;
+}
+
+void
+ifs_remque(ifm)
+	struct mbuf *ifm;
+{
+	ifm->ifs_prev->ifs_next = ifm->ifs_next;
+	ifm->ifs_next->ifs_prev = ifm->ifs_prev;
+}
+
+void
+if_init()
+{
+#if 0
+	/*
+	 * Set if_maxlinkhdr to 48 because it's 40 bytes for TCP/IP,
+	 * and 8 bytes for PPP, but need to have it on an 8byte boundary
+	 */
+#ifdef USE_PPP
+	if_maxlinkhdr = 48;
+#else
+	if_maxlinkhdr = 40;
+#endif
+#else
+        /* 14 for ethernet + 40 */
+        if_maxlinkhdr = 14 + 40;
+#endif
+	if_mtu = 1500;
+	if_mru = 1500;
+	if_comp = IF_AUTOCOMP;
+	if_fastq.ifq_next = if_fastq.ifq_prev = &if_fastq;
+	if_batchq.ifq_next = if_batchq.ifq_prev = &if_batchq;
+        //	sl_compress_init(&comp_s);
+	next_m = &if_batchq;
+}
+
+#if 0
+/*
+ * This shouldn't be needed since the modem is blocking and
+ * we don't expect any signals, but what the hell..
+ */
+inline int
+writen(fd, bptr, n)
+	int fd;
+	char *bptr;
+	int n;
+{
+	int ret;
+	int total;
+	
+	/* This should succeed most of the time */
+	ret = write(fd, bptr, n);
+	if (ret == n || ret <= 0)
+	   return ret;
+	
+	/* Didn't write everything, go into the loop */
+	total = ret;
+	while (n > total) {
+		ret = write(fd, bptr+total, n-total);
+		if (ret <= 0)
+		   return ret;
+		total += ret;
+	}
+	return total;
+}
+
+/*
+ * if_input - read() the tty, do "top level" processing (ie: check for any escapes),
+ * and pass onto (*ttyp->if_input)
+ * 
+ * XXXXX Any zeros arriving by themselves are NOT placed into the arriving packet.
+ */
+#define INBUFF_SIZE 2048 /* XXX */
+void
+if_input(ttyp)
+	struct ttys *ttyp;
+{
+	u_char if_inbuff[INBUFF_SIZE];
+	int if_n;
+	
+	DEBUG_CALL("if_input");
+	DEBUG_ARG("ttyp = %lx", (long)ttyp);
+	
+	if_n = read(ttyp->fd, (char *)if_inbuff, INBUFF_SIZE);
+	
+	DEBUG_MISC((dfd, " read %d bytes\n", if_n));
+	
+	if (if_n <= 0) {
+		if (if_n == 0 || (errno != EINTR && errno != EAGAIN)) {
+			if (ttyp->up)
+			   link_up--;
+			tty_detached(ttyp, 0);
+		}
+		return;
+	}
+	if (if_n == 1) {
+		if (*if_inbuff == '0') {
+			ttyp->ones = 0;
+			if (++ttyp->zeros >= 5)
+			   slirp_exit(0);
+			return;
+		}
+		if (*if_inbuff == '1') {
+			ttyp->zeros = 0;
+			if (++ttyp->ones >= 5)
+			   tty_detached(ttyp, 0);
+			return;
+		}
+	}
+	ttyp->ones = ttyp->zeros = 0;
+	
+	(*ttyp->if_input)(ttyp, if_inbuff, if_n);
+}
+#endif	
+	
+/*
+ * if_output: Queue packet into an output queue.
+ * There are 2 output queue's, if_fastq and if_batchq. 
+ * Each output queue is a doubly linked list of double linked lists
+ * of mbufs, each list belonging to one "session" (socket).  This
+ * way, we can output packets fairly by sending one packet from each
+ * session, instead of all the packets from one session, then all packets
+ * from the next session, etc.  Packets on the if_fastq get absolute 
+ * priority, but if one session hogs the link, it gets "downgraded"
+ * to the batchq until it runs out of packets, then it'll return
+ * to the fastq (eg. if the user does an ls -alR in a telnet session,
+ * it'll temporarily get downgraded to the batchq)
+ */
+void
+if_output(so, ifm)
+	struct socket *so;
+	struct mbuf *ifm;
+{
+	struct mbuf *ifq;
+	int on_fastq = 1;
+	
+	DEBUG_CALL("if_output");
+	DEBUG_ARG("so = %lx", (long)so);
+	DEBUG_ARG("ifm = %lx", (long)ifm);
+	
+	/*
+	 * First remove the mbuf from m_usedlist,
+	 * since we're gonna use m_next and m_prev ourselves
+	 * XXX Shouldn't need this, gotta change dtom() etc.
+	 */
+	if (ifm->m_flags & M_USEDLIST) {
+		remque(ifm);
+		ifm->m_flags &= ~M_USEDLIST;
+	}
+	
+	/*
+	 * See if there's already a batchq list for this session.  
+	 * This can include an interactive session, which should go on fastq,
+	 * but gets too greedy... hence it'll be downgraded from fastq to batchq.
+	 * We mustn't put this packet back on the fastq (or we'll send it out of order)
+	 * XXX add cache here?
+	 */
+	for (ifq = if_batchq.ifq_prev; ifq != &if_batchq; ifq = ifq->ifq_prev) {
+		if (so == ifq->ifq_so) {
+			/* A match! */
+			ifm->ifq_so = so;
+			ifs_insque(ifm, ifq->ifs_prev);
+			goto diddit;
+		}
+	}
+	
+	/* No match, check which queue to put it on */
+	if (so && (so->so_iptos & IPTOS_LOWDELAY)) {
+		ifq = if_fastq.ifq_prev;
+		on_fastq = 1;
+		/*
+		 * Check if this packet is a part of the last
+		 * packet's session
+		 */
+		if (ifq->ifq_so == so) {
+			ifm->ifq_so = so;
+			ifs_insque(ifm, ifq->ifs_prev);
+			goto diddit;
+		}
+	} else
+		ifq = if_batchq.ifq_prev;
+	
+	/* Create a new doubly linked list for this session */
+	ifm->ifq_so = so;
+	ifs_init(ifm);
+	insque(ifm, ifq);
+	
+diddit:
+	++if_queued;
+	
+	if (so) {
+		/* Update *_queued */
+		so->so_queued++;
+		so->so_nqueued++;
+		/*
+		 * Check if the interactive session should be downgraded to
+		 * the batchq.  A session is downgraded if it has queued 6
+		 * packets without pausing, and at least 3 of those packets
+		 * have been sent over the link
+		 * (XXX These are arbitrary numbers, probably not optimal..)
+		 */
+		if (on_fastq && ((so->so_nqueued >= 6) && 
+				 (so->so_nqueued - so->so_queued) >= 3)) {
+			
+			/* Remove from current queue... */
+			remque(ifm->ifs_next);
+			
+			/* ...And insert in the new.  That'll teach ya! */
+			insque(ifm->ifs_next, &if_batchq);
+		}
+	}
+
+#ifndef FULL_BOLT
+	/*
+	 * This prevents us from malloc()ing too many mbufs
+	 */
+	if (link_up) {
+		/* if_start will check towrite */
+		if_start();
+	}
+#endif
+}
+
+/*
+ * Send a packet
+ * We choose a packet based on it's position in the output queues;
+ * If there are packets on the fastq, they are sent FIFO, before
+ * everything else.  Otherwise we choose the first packet from the
+ * batchq and send it.  the next packet chosen will be from the session
+ * after this one, then the session after that one, and so on..  So,
+ * for example, if there are 3 ftp session's fighting for bandwidth,
+ * one packet will be sent from the first session, then one packet
+ * from the second session, then one packet from the third, then back
+ * to the first, etc. etc.
+ */
+void
+if_start(void)
+{
+	struct mbuf *ifm, *ifqt;
+	
+	DEBUG_CALL("if_start");
+	
+	if (if_queued == 0)
+	   return; /* Nothing to do */
+	
+ again:
+        /* check if we can really output */
+        if (!slirp_can_output())
+            return;
+
+	/*
+	 * See which queue to get next packet from
+	 * If there's something in the fastq, select it immediately
+	 */
+	if (if_fastq.ifq_next != &if_fastq) {
+		ifm = if_fastq.ifq_next;
+	} else {
+		/* Nothing on fastq, see if next_m is valid */
+		if (next_m != &if_batchq)
+		   ifm = next_m;
+		else
+		   ifm = if_batchq.ifq_next;
+		
+		/* Set which packet to send on next iteration */
+		next_m = ifm->ifq_next;
+	}
+	/* Remove it from the queue */
+	ifqt = ifm->ifq_prev;
+	remque(ifm);
+	--if_queued;
+	
+	/* If there are more packets for this session, re-queue them */
+	if (ifm->ifs_next != /* ifm->ifs_prev != */ ifm) {
+		insque(ifm->ifs_next, ifqt);
+		ifs_remque(ifm);
+	}
+	
+	/* Update so_queued */
+	if (ifm->ifq_so) {
+		if (--ifm->ifq_so->so_queued == 0)
+		   /* If there's no more queued, reset nqueued */
+		   ifm->ifq_so->so_nqueued = 0;
+	}
+	
+	/* Encapsulate the packet for sending */
+        if_encap(ifm->m_data, ifm->m_len);
+
+	if (if_queued)
+	   goto again;
+}
diff --git a/slirp/if.h b/slirp/if.h
new file mode 100644
index 000000000..5d96a9034
--- /dev/null
+++ b/slirp/if.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#ifndef _IF_H_
+#define _IF_H_
+
+#define IF_COMPRESS	0x01	/* We want compression */
+#define IF_NOCOMPRESS	0x02	/* Do not do compression */
+#define IF_AUTOCOMP	0x04	/* Autodetect (default) */
+#define IF_NOCIDCOMP	0x08	/* CID compression */
+
+/* Needed for FreeBSD */
+#undef if_mtu
+extern int	if_mtu;
+extern int	if_mru;	/* MTU and MRU */
+extern int	if_comp;	/* Flags for compression */
+extern int	if_maxlinkhdr;
+extern int	if_queued;	/* Number of packets queued so far */
+extern int	if_thresh;	/* Number of packets queued before we start sending
+				 * (to prevent allocing too many mbufs) */
+
+extern	struct mbuf if_fastq;                  /* fast queue (for interactive data) */
+extern	struct mbuf if_batchq;                 /* queue for non-interactive data */
+extern	struct mbuf *next_m;
+
+#define ifs_init(ifm) ((ifm)->ifs_next = (ifm)->ifs_prev = (ifm))
+
+/* Interface statistics */
+struct slirp_ifstats {
+	u_int out_pkts;		/* Output packets */
+	u_int out_bytes;		/* Output bytes */
+	u_int out_errpkts;	/* Output Error Packets */
+	u_int out_errbytes;	/* Output Error Bytes */
+	u_int in_pkts;		/* Input packets */
+	u_int in_bytes;		/* Input bytes */
+	u_int in_errpkts;		/* Input Error Packets */
+	u_int in_errbytes;	/* Input Error Bytes */
+	
+	u_int bytes_saved;	/* Number of bytes that compression "saved" */
+				/* ie: number of bytes that didn't need to be sent over the link
+				 * because of compression */
+	
+	u_int in_mbad;		/* Bad incoming packets */
+};
+
+#endif
diff --git a/slirp/ip.h b/slirp/ip.h
new file mode 100644
index 000000000..8280e55b8
--- /dev/null
+++ b/slirp/ip.h
@@ -0,0 +1,317 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip.h	8.1 (Berkeley) 6/10/93
+ * ip.h,v 1.3 1994/08/21 05:27:30 paul Exp
+ */
+
+#ifndef _IP_H_
+#define _IP_H_
+
+#ifdef WORDS_BIGENDIAN
+# ifndef NTOHL
+#  define NTOHL(d)
+# endif
+# ifndef NTOHS
+#  define NTOHS(d)
+# endif
+# ifndef HTONL
+#  define HTONL(d)
+# endif
+# ifndef HTONS
+#  define HTONS(d)
+# endif
+#else
+# ifndef NTOHL
+#  define NTOHL(d) ((d) = ntohl((d)))
+# endif
+# ifndef NTOHS
+#  define NTOHS(d) ((d) = ntohs((u_int16_t)(d)))
+# endif
+# ifndef HTONL
+#  define HTONL(d) ((d) = htonl((d)))
+# endif
+# ifndef HTONS
+#  define HTONS(d) ((d) = htons((u_int16_t)(d)))
+# endif
+#endif
+
+typedef u_int32_t n_long;                 /* long as received from the net */
+
+/*
+ * Definitions for internet protocol version 4.
+ * Per RFC 791, September 1981.
+ */
+#define	IPVERSION	4
+
+/*
+ * Structure of an internet header, naked of options.
+ *
+ * We declare ip_len and ip_off to be short, rather than u_short
+ * pragmatically since otherwise unsigned comparisons can result
+ * against negative integers quite easily, and fail in subtle ways.
+ */
+struct ip {
+#ifdef WORDS_BIGENDIAN
+	u_int ip_v:4,			/* version */
+		ip_hl:4;		/* header length */
+#else
+	u_int ip_hl:4,		/* header length */
+		ip_v:4;			/* version */
+#endif
+	u_int8_t ip_tos;			/* type of service */
+	int16_t	ip_len;			/* total length */
+	u_int16_t	ip_id;			/* identification */
+	int16_t	ip_off;			/* fragment offset field */
+#define	IP_DF 0x4000			/* don't fragment flag */
+#define	IP_MF 0x2000			/* more fragments flag */
+#define	IP_OFFMASK 0x1fff		/* mask for fragmenting bits */
+	u_int8_t ip_ttl;			/* time to live */
+	u_int8_t ip_p;			/* protocol */
+	u_int16_t	ip_sum;			/* checksum */
+	struct	in_addr ip_src,ip_dst;	/* source and dest address */
+};
+
+#define	IP_MAXPACKET	65535		/* maximum packet size */
+
+/*
+ * Definitions for IP type of service (ip_tos)
+ */
+#define	IPTOS_LOWDELAY		0x10
+#define	IPTOS_THROUGHPUT	0x08
+#define	IPTOS_RELIABILITY	0x04
+
+/*
+ * Definitions for options.
+ */
+#define	IPOPT_COPIED(o)		((o)&0x80)
+#define	IPOPT_CLASS(o)		((o)&0x60)
+#define	IPOPT_NUMBER(o)		((o)&0x1f)
+
+#define	IPOPT_CONTROL		0x00
+#define	IPOPT_RESERVED1		0x20
+#define	IPOPT_DEBMEAS		0x40
+#define	IPOPT_RESERVED2		0x60
+
+#define	IPOPT_EOL		0		/* end of option list */
+#define	IPOPT_NOP		1		/* no operation */
+
+#define	IPOPT_RR		7		/* record packet route */
+#define	IPOPT_TS		68		/* timestamp */
+#define	IPOPT_SECURITY		130		/* provide s,c,h,tcc */
+#define	IPOPT_LSRR		131		/* loose source route */
+#define	IPOPT_SATID		136		/* satnet id */
+#define	IPOPT_SSRR		137		/* strict source route */
+
+/*
+ * Offsets to fields in options other than EOL and NOP.
+ */
+#define	IPOPT_OPTVAL		0		/* option ID */
+#define	IPOPT_OLEN		1		/* option length */
+#define IPOPT_OFFSET		2		/* offset within option */
+#define	IPOPT_MINOFF		4		/* min value of above */
+
+/*
+ * Time stamp option structure.
+ */
+struct	ip_timestamp {
+	u_int8_t	ipt_code;		/* IPOPT_TS */
+	u_int8_t	ipt_len;		/* size of structure (variable) */
+	u_int8_t	ipt_ptr;		/* index of current entry */
+#ifdef WORDS_BIGENDIAN
+	u_int	ipt_oflw:4,		/* overflow counter */
+		ipt_flg:4;		/* flags, see below */
+#else
+	u_int	ipt_flg:4,		/* flags, see below */
+		ipt_oflw:4;		/* overflow counter */
+#endif
+	union ipt_timestamp {
+		n_long	ipt_time[1];
+		struct	ipt_ta {
+			struct in_addr ipt_addr;
+			n_long ipt_time;
+		} ipt_ta[1];
+	} ipt_timestamp;
+};
+
+/* flag bits for ipt_flg */
+#define	IPOPT_TS_TSONLY		0		/* timestamps only */
+#define	IPOPT_TS_TSANDADDR	1		/* timestamps and addresses */
+#define	IPOPT_TS_PRESPEC	3		/* specified modules only */
+
+/* bits for security (not byte swapped) */
+#define	IPOPT_SECUR_UNCLASS	0x0000
+#define	IPOPT_SECUR_CONFID	0xf135
+#define	IPOPT_SECUR_EFTO	0x789a
+#define	IPOPT_SECUR_MMMM	0xbc4d
+#define	IPOPT_SECUR_RESTR	0xaf13
+#define	IPOPT_SECUR_SECRET	0xd788
+#define	IPOPT_SECUR_TOPSECRET	0x6bc5
+
+/*
+ * Internet implementation parameters.
+ */
+#define	MAXTTL		255		/* maximum time to live (seconds) */
+#define	IPDEFTTL	64		/* default ttl, from RFC 1340 */
+#define	IPFRAGTTL	60		/* time to live for frags, slowhz */
+#define	IPTTLDEC	1		/* subtracted when forwarding */
+
+#define	IP_MSS		576		/* default maximum segment size */
+
+#ifdef HAVE_SYS_TYPES32_H  /* Overcome some Solaris 2.x junk */
+#include <sys/types32.h>
+#else
+#if SIZEOF_CHAR_P == 4
+typedef caddr_t caddr32_t;
+#else
+typedef u_int32_t caddr32_t;
+#endif
+#endif
+
+#if SIZEOF_CHAR_P == 4
+typedef struct ipq *ipqp_32;
+typedef struct ipasfrag *ipasfragp_32;
+#else
+typedef caddr32_t ipqp_32;
+typedef caddr32_t ipasfragp_32;
+#endif
+
+/*
+ * Overlay for ip header used by other protocols (tcp, udp).
+ */
+struct ipovly {
+	caddr32_t	ih_next, ih_prev;	/* for protocol sequence q's */
+	u_int8_t	ih_x1;			/* (unused) */
+	u_int8_t	ih_pr;			/* protocol */
+	int16_t	ih_len;			/* protocol length */
+	struct	in_addr ih_src;		/* source internet address */
+	struct	in_addr ih_dst;		/* destination internet address */
+};
+
+/*
+ * Ip reassembly queue structure.  Each fragment
+ * being reassembled is attached to one of these structures.
+ * They are timed out after ipq_ttl drops to 0, and may also
+ * be reclaimed if memory becomes tight.
+ * size 28 bytes
+ */
+struct ipq {
+	ipqp_32 next,prev;	/* to other reass headers */
+	u_int8_t	ipq_ttl;		/* time for reass q to live */
+	u_int8_t	ipq_p;			/* protocol of this fragment */
+	u_int16_t	ipq_id;			/* sequence id for reassembly */
+	ipasfragp_32 ipq_next,ipq_prev;
+					/* to ip headers of fragments */
+	struct	in_addr ipq_src,ipq_dst;
+};
+
+/*
+ * Ip header, when holding a fragment.
+ *
+ * Note: ipf_next must be at same offset as ipq_next above
+ */
+struct	ipasfrag {
+#ifdef WORDS_BIGENDIAN
+	u_int	ip_v:4,
+ 		ip_hl:4;
+#else
+	u_int	ip_hl:4,
+		ip_v:4;
+#endif
+                                        /* BUG : u_int changed to u_int8_t.
+                                         * sizeof(u_int)==4 on linux 2.0
+					 */
+        u_int8_t ipf_mff;		/* XXX overlays ip_tos: use low bit
+					 * to avoid destroying tos (PPPDTRuu);
+					 * copied from (ip_off&IP_MF) */
+	int16_t	ip_len;
+	u_int16_t	ip_id;
+	int16_t	ip_off;
+	u_int8_t	ip_ttl;
+	u_int8_t	ip_p;
+	u_int16_t	ip_sum;
+	ipasfragp_32 ipf_next;		/* next fragment */
+	ipasfragp_32 ipf_prev;		/* previous fragment */
+};
+
+/*
+ * Structure stored in mbuf in inpcb.ip_options
+ * and passed to ip_output when ip options are in use.
+ * The actual length of the options (including ipopt_dst)
+ * is in m_len.
+ */
+#define MAX_IPOPTLEN	40
+
+struct ipoption {
+	struct	in_addr ipopt_dst;	/* first-hop dst if source routed */
+	int8_t	ipopt_list[MAX_IPOPTLEN];	/* options proper */
+};
+
+/*
+ * Structure attached to inpcb.ip_moptions and
+ * passed to ip_output when IP multicast options are in use.
+ */
+
+struct	ipstat {
+	u_long	ips_total;		/* total packets received */
+	u_long	ips_badsum;		/* checksum bad */
+	u_long	ips_tooshort;		/* packet too short */
+	u_long	ips_toosmall;		/* not enough data */
+	u_long	ips_badhlen;		/* ip header length < data size */
+	u_long	ips_badlen;		/* ip length < ip header length */
+	u_long	ips_fragments;		/* fragments received */
+	u_long	ips_fragdropped;	/* frags dropped (dups, out of space) */
+	u_long	ips_fragtimeout;	/* fragments timed out */
+	u_long	ips_forward;		/* packets forwarded */
+	u_long	ips_cantforward;	/* packets rcvd for unreachable dest */
+	u_long	ips_redirectsent;	/* packets forwarded on same net */
+	u_long	ips_noproto;		/* unknown or unsupported protocol */
+	u_long	ips_delivered;		/* datagrams delivered to upper level*/
+	u_long	ips_localout;		/* total ip packets generated here */
+	u_long	ips_odropped;		/* lost packets due to nobufs, etc. */
+	u_long	ips_reassembled;	/* total packets reassembled ok */
+	u_long	ips_fragmented;		/* datagrams successfully fragmented */
+	u_long	ips_ofragments;		/* output fragments created */
+	u_long	ips_cantfrag;		/* don't fragment flag was set, etc. */
+	u_long	ips_badoptions;		/* error in option processing */
+	u_long	ips_noroute;		/* packets discarded due to no route */
+	u_long	ips_badvers;		/* ip version != 4 */
+	u_long	ips_rawout;		/* total raw ip packets generated */
+	u_long	ips_unaligned;		/* times the ip packet was not aligned */
+};
+
+extern struct	ipstat	ipstat;
+extern struct	ipq	ipq;			/* ip reass. queue */
+extern u_int16_t	ip_id;				/* ip packet ctr, for ids */
+extern int	ip_defttl;			/* default IP ttl */
+
+#endif
diff --git a/slirp/ip_icmp.c b/slirp/ip_icmp.c
new file mode 100644
index 000000000..8bc97a078
--- /dev/null
+++ b/slirp/ip_icmp.c
@@ -0,0 +1,376 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip_icmp.c	8.2 (Berkeley) 1/4/94
+ * ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp
+ */
+
+#include "slirp.h"
+#include "ip_icmp.h"
+
+struct icmpstat icmpstat;
+
+/* The message sent when emulating PING */
+/* Be nice and tell them it's just a psuedo-ping packet */
+char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
+
+/* list of actions for icmp_error() on RX of an icmp message */
+static int icmp_flush[19] = {
+/*  ECHO REPLY (0)  */   0,
+		         1,
+		         1,
+/* DEST UNREACH (3) */   1,
+/* SOURCE QUENCH (4)*/   1,
+/* REDIRECT (5) */       1,
+		         1,
+		         1,
+/* ECHO (8) */           0,
+/* ROUTERADVERT (9) */   1,
+/* ROUTERSOLICIT (10) */ 1,
+/* TIME EXCEEDED (11) */ 1,
+/* PARAMETER PROBLEM (12) */ 1,
+/* TIMESTAMP (13) */     0,
+/* TIMESTAMP REPLY (14) */ 0,
+/* INFO (15) */          0,
+/* INFO REPLY (16) */    0,
+/* ADDR MASK (17) */     0,
+/* ADDR MASK REPLY (18) */ 0 
+};
+
+/*
+ * Process a received ICMP message.
+ */
+void
+icmp_input(m, hlen)
+     struct mbuf *m;
+     int hlen;
+{
+  register struct icmp *icp;
+  register struct ip *ip=mtod(m, struct ip *);
+  int icmplen=ip->ip_len;
+  /* int code; */
+	
+  DEBUG_CALL("icmp_input");
+  DEBUG_ARG("m = %lx", (long )m);
+  DEBUG_ARG("m_len = %d", m->m_len);
+
+  icmpstat.icps_received++;
+	
+  /*
+   * Locate icmp structure in mbuf, and check
+   * that its not corrupted and of at least minimum length.
+   */
+  if (icmplen < ICMP_MINLEN) {          /* min 8 bytes payload */
+    icmpstat.icps_tooshort++;
+  freeit:
+    m_freem(m);
+    goto end_error;
+  }
+
+  m->m_len -= hlen;
+  m->m_data += hlen;
+  icp = mtod(m, struct icmp *);
+  if (cksum(m, icmplen)) {
+    icmpstat.icps_checksum++;
+    goto freeit;
+  }
+  m->m_len += hlen;
+  m->m_data -= hlen;
+  
+  /*	icmpstat.icps_inhist[icp->icmp_type]++; */
+  /* code = icp->icmp_code; */
+
+  DEBUG_ARG("icmp_type = %d", icp->icmp_type);
+  switch (icp->icmp_type) {
+  case ICMP_ECHO:
+    icp->icmp_type = ICMP_ECHOREPLY;
+    ip->ip_len += hlen;	             /* since ip_input subtracts this */
+    if (ip->ip_dst.s_addr == our_addr.s_addr || 
+	(ip->ip_dst.s_addr == (special_addr.s_addr|htonl(CTL_ALIAS))) ) {
+      icmp_reflect(m);
+    } else {
+      struct socket *so;
+      struct sockaddr_in addr;
+      if ((so = socreate()) == NULL) goto freeit;
+      if(udp_attach(so) == -1) {
+	DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n", 
+		    errno,strerror(errno)));
+	sofree(so);
+	m_free(m);
+	goto end_error;
+      }
+      so->so_m = m;
+      so->so_faddr = ip->ip_dst;
+      so->so_fport = htons(7);
+      so->so_laddr = ip->ip_src;
+      so->so_lport = htons(9);
+      so->so_iptos = ip->ip_tos;
+      so->so_type = IPPROTO_ICMP;
+      so->so_state = SS_ISFCONNECTED;
+      
+      /* Send the packet */
+      addr.sin_family = AF_INET;
+      if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) {
+	/* It's an alias */
+	switch(ntohl(so->so_faddr.s_addr) & 0xff) {
+	case CTL_DNS:
+	  addr.sin_addr = dns_addr;
+	  break;
+	case CTL_ALIAS:
+	default:
+	  addr.sin_addr = loopback_addr;
+	  break;
+	}
+      } else {
+	addr.sin_addr = so->so_faddr;
+      }
+      addr.sin_port = so->so_fport;
+      if(sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0,
+		(struct sockaddr *)&addr, sizeof(addr)) == -1) {
+	DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
+		    errno,strerror(errno)));
+	icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno)); 
+	udp_detach(so);
+      }
+    } /* if ip->ip_dst.s_addr == our_addr.s_addr */
+    break;
+  case ICMP_UNREACH:
+    /* XXX? report error? close socket? */
+  case ICMP_TIMXCEED:
+  case ICMP_PARAMPROB:
+  case ICMP_SOURCEQUENCH:
+  case ICMP_TSTAMP:
+  case ICMP_MASKREQ:
+  case ICMP_REDIRECT:
+    icmpstat.icps_notsupp++;
+    m_freem(m);
+    break;
+    
+  default:
+    icmpstat.icps_badtype++;
+    m_freem(m);
+  } /* swith */
+
+end_error:
+  /* m is m_free()'d xor put in a socket xor or given to ip_send */
+  return;
+}
+
+
+/*
+ *	Send an ICMP message in response to a situation
+ *
+ *	RFC 1122: 3.2.2	MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
+ *			MUST NOT change this header information.
+ *			MUST NOT reply to a multicast/broadcast IP address.
+ *			MUST NOT reply to a multicast/broadcast MAC address.
+ *			MUST reply to only the first fragment.
+ */
+/*
+ * Send ICMP_UNREACH back to the source regarding msrc.
+ * mbuf *msrc is used as a template, but is NOT m_free()'d.
+ * It is reported as the bad ip packet.  The header should
+ * be fully correct and in host byte order.
+ * ICMP fragmentation is illegal.  All machines must accept 576 bytes in one 
+ * packet.  The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
+ */
+
+#define ICMP_MAXDATALEN (IP_MSS-28)
+void
+icmp_error(msrc, type, code, minsize, message)
+     struct mbuf *msrc;
+     u_char type;
+     u_char code;
+     int minsize;
+     char *message;
+{
+  unsigned hlen, shlen, s_ip_len;
+  register struct ip *ip;
+  register struct icmp *icp;
+  register struct mbuf *m;
+
+  DEBUG_CALL("icmp_error");
+  DEBUG_ARG("msrc = %lx", (long )msrc);
+  DEBUG_ARG("msrc_len = %d", msrc->m_len);
+
+  if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error;
+
+  /* check msrc */
+  if(!msrc) goto end_error;
+  ip = mtod(msrc, struct ip *);
+#if DEBUG  
+  { char bufa[20], bufb[20];
+    strcpy(bufa, inet_ntoa(ip->ip_src));
+    strcpy(bufb, inet_ntoa(ip->ip_dst));
+    DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
+  }
+#endif
+  if(ip->ip_off & IP_OFFMASK) goto end_error;    /* Only reply to fragment 0 */
+
+  shlen=ip->ip_hl << 2;
+  s_ip_len=ip->ip_len;
+  if(ip->ip_p == IPPROTO_ICMP) {
+    icp = (struct icmp *)((char *)ip + shlen);
+    /*
+     *	Assume any unknown ICMP type is an error. This isn't
+     *	specified by the RFC, but think about it..
+     */
+    if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error;
+  }
+
+  /* make a copy */
+  if(!(m=m_get())) goto end_error;               /* get mbuf */
+  { int new_m_size;
+    new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN;
+    if(new_m_size>m->m_size) m_inc(m, new_m_size);
+  }
+  memcpy(m->m_data, msrc->m_data, msrc->m_len);
+  m->m_len = msrc->m_len;                        /* copy msrc to m */
+
+  /* make the header of the reply packet */
+  ip  = mtod(m, struct ip *);
+  hlen= sizeof(struct ip );     /* no options in reply */
+  
+  /* fill in icmp */
+  m->m_data += hlen;                  
+  m->m_len -= hlen;
+
+  icp = mtod(m, struct icmp *);
+
+  if(minsize) s_ip_len=shlen+ICMP_MINLEN;   /* return header+8b only */
+  else if(s_ip_len>ICMP_MAXDATALEN)         /* maximum size */
+    s_ip_len=ICMP_MAXDATALEN;
+
+  m->m_len=ICMP_MINLEN+s_ip_len;        /* 8 bytes ICMP header */  
+
+  /* min. size = 8+sizeof(struct ip)+8 */
+
+  icp->icmp_type = type;
+  icp->icmp_code = code;
+  icp->icmp_id = 0;
+  icp->icmp_seq = 0;
+
+  memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len);   /* report the ip packet */
+  HTONS(icp->icmp_ip.ip_len);
+  HTONS(icp->icmp_ip.ip_id);
+  HTONS(icp->icmp_ip.ip_off);
+
+#if DEBUG
+  if(message) {           /* DEBUG : append message to ICMP packet */
+    int message_len;
+    char *cpnt;
+    message_len=strlen(message);
+    if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN;
+    cpnt=(char *)m->m_data+m->m_len;
+    memcpy(cpnt, message, message_len);
+    m->m_len+=message_len;
+  }
+#endif
+
+  icp->icmp_cksum = 0;
+  icp->icmp_cksum = cksum(m, m->m_len);
+
+  m->m_data -= hlen;
+  m->m_len += hlen;
+
+  /* fill in ip */
+  ip->ip_hl = hlen >> 2;
+  ip->ip_len = m->m_len;
+  
+  ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0);  /* high priority for errors */
+
+  ip->ip_ttl = MAXTTL;
+  ip->ip_p = IPPROTO_ICMP;
+  ip->ip_dst = ip->ip_src;    /* ip adresses */
+  ip->ip_src = our_addr;
+
+  (void ) ip_output((struct socket *)NULL, m);
+  
+  icmpstat.icps_reflect++;
+
+end_error:
+  return;
+}
+#undef ICMP_MAXDATALEN
+
+/*
+ * Reflect the ip packet back to the source
+ */
+void
+icmp_reflect(m)
+     struct mbuf *m;
+{
+  register struct ip *ip = mtod(m, struct ip *);
+  int hlen = ip->ip_hl << 2;
+  int optlen = hlen - sizeof(struct ip );
+  register struct icmp *icp;
+
+  /*
+   * Send an icmp packet back to the ip level,
+   * after supplying a checksum.
+   */
+  m->m_data += hlen;
+  m->m_len -= hlen;
+  icp = mtod(m, struct icmp *);
+
+  icp->icmp_cksum = 0;
+  icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
+
+  m->m_data -= hlen;
+  m->m_len += hlen;
+
+  /* fill in ip */
+  if (optlen > 0) {
+    /*
+     * Strip out original options by copying rest of first
+     * mbuf's data back, and adjust the IP length.
+     */
+    memmove((caddr_t)(ip + 1), (caddr_t)ip + hlen,
+	    (unsigned )(m->m_len - hlen));
+    hlen -= optlen;
+    ip->ip_hl = hlen >> 2;
+    ip->ip_len -= optlen;
+    m->m_len -= optlen;
+  }
+
+  ip->ip_ttl = MAXTTL;
+  { /* swap */
+    struct in_addr icmp_dst;
+    icmp_dst = ip->ip_dst;
+    ip->ip_dst = ip->ip_src;
+    ip->ip_src = icmp_dst;
+  }
+
+  (void ) ip_output((struct socket *)NULL, m);
+
+  icmpstat.icps_reflect++;
+}
diff --git a/slirp/ip_icmp.h b/slirp/ip_icmp.h
new file mode 100644
index 000000000..7ddaaf8f3
--- /dev/null
+++ b/slirp/ip_icmp.h
@@ -0,0 +1,164 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip_icmp.h	8.1 (Berkeley) 6/10/93
+ * ip_icmp.h,v 1.4 1995/05/30 08:09:43 rgrimes Exp
+ */
+
+#ifndef _NETINET_IP_ICMP_H_
+#define _NETINET_IP_ICMP_H_
+
+/*
+ * Interface Control Message Protocol Definitions.
+ * Per RFC 792, September 1981.
+ */
+
+typedef u_int32_t n_time;
+
+/*
+ * Structure of an icmp header.
+ */
+struct icmp {
+	u_char	icmp_type;		/* type of message, see below */
+	u_char	icmp_code;		/* type sub code */
+	u_short	icmp_cksum;		/* ones complement cksum of struct */
+	union {
+		u_char ih_pptr;			/* ICMP_PARAMPROB */
+		struct in_addr ih_gwaddr;	/* ICMP_REDIRECT */
+		struct ih_idseq {
+			u_short	icd_id;
+			u_short	icd_seq;
+		} ih_idseq;
+		int ih_void;
+
+		/* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */
+		struct ih_pmtu {
+			u_short ipm_void;
+			u_short ipm_nextmtu;
+		} ih_pmtu;
+	} icmp_hun;
+#define	icmp_pptr	icmp_hun.ih_pptr
+#define	icmp_gwaddr	icmp_hun.ih_gwaddr
+#define	icmp_id		icmp_hun.ih_idseq.icd_id
+#define	icmp_seq	icmp_hun.ih_idseq.icd_seq
+#define	icmp_void	icmp_hun.ih_void
+#define	icmp_pmvoid	icmp_hun.ih_pmtu.ipm_void
+#define	icmp_nextmtu	icmp_hun.ih_pmtu.ipm_nextmtu
+	union {
+		struct id_ts {
+			n_time its_otime;
+			n_time its_rtime;
+			n_time its_ttime;
+		} id_ts;
+		struct id_ip  {
+			struct ip idi_ip;
+			/* options and then 64 bits of data */
+		} id_ip;
+		u_long	id_mask;
+		char	id_data[1];
+	} icmp_dun;
+#define	icmp_otime	icmp_dun.id_ts.its_otime
+#define	icmp_rtime	icmp_dun.id_ts.its_rtime
+#define	icmp_ttime	icmp_dun.id_ts.its_ttime
+#define	icmp_ip		icmp_dun.id_ip.idi_ip
+#define	icmp_mask	icmp_dun.id_mask
+#define	icmp_data	icmp_dun.id_data
+};
+
+/*
+ * Lower bounds on packet lengths for various types.
+ * For the error advice packets must first insure that the
+ * packet is large enought to contain the returned ip header.
+ * Only then can we do the check to see if 64 bits of packet
+ * data have been returned, since we need to check the returned
+ * ip header length.
+ */
+#define	ICMP_MINLEN	8				/* abs minimum */
+#define	ICMP_TSLEN	(8 + 3 * sizeof (n_time))	/* timestamp */
+#define	ICMP_MASKLEN	12				/* address mask */
+#define	ICMP_ADVLENMIN	(8 + sizeof (struct ip) + 8)	/* min */
+#define	ICMP_ADVLEN(p)	(8 + ((p)->icmp_ip.ip_hl << 2) + 8)
+	/* N.B.: must separately check that ip_hl >= 5 */
+
+/*
+ * Definition of type and code field values.
+ */
+#define	ICMP_ECHOREPLY		0		/* echo reply */
+#define	ICMP_UNREACH		3		/* dest unreachable, codes: */
+#define		ICMP_UNREACH_NET	0		/* bad net */
+#define		ICMP_UNREACH_HOST	1		/* bad host */
+#define		ICMP_UNREACH_PROTOCOL	2		/* bad protocol */
+#define		ICMP_UNREACH_PORT	3		/* bad port */
+#define		ICMP_UNREACH_NEEDFRAG	4		/* IP_DF caused drop */
+#define		ICMP_UNREACH_SRCFAIL	5		/* src route failed */
+#define		ICMP_UNREACH_NET_UNKNOWN 6		/* unknown net */
+#define		ICMP_UNREACH_HOST_UNKNOWN 7		/* unknown host */
+#define		ICMP_UNREACH_ISOLATED	8		/* src host isolated */
+#define		ICMP_UNREACH_NET_PROHIB	9		/* prohibited access */
+#define		ICMP_UNREACH_HOST_PROHIB 10		/* ditto */
+#define		ICMP_UNREACH_TOSNET	11		/* bad tos for net */
+#define		ICMP_UNREACH_TOSHOST	12		/* bad tos for host */
+#define	ICMP_SOURCEQUENCH	4		/* packet lost, slow down */
+#define	ICMP_REDIRECT		5		/* shorter route, codes: */
+#define		ICMP_REDIRECT_NET	0		/* for network */
+#define		ICMP_REDIRECT_HOST	1		/* for host */
+#define		ICMP_REDIRECT_TOSNET	2		/* for tos and net */
+#define		ICMP_REDIRECT_TOSHOST	3		/* for tos and host */
+#define	ICMP_ECHO		8		/* echo service */
+#define	ICMP_ROUTERADVERT	9		/* router advertisement */
+#define	ICMP_ROUTERSOLICIT	10		/* router solicitation */
+#define	ICMP_TIMXCEED		11		/* time exceeded, code: */
+#define		ICMP_TIMXCEED_INTRANS	0		/* ttl==0 in transit */
+#define		ICMP_TIMXCEED_REASS	1		/* ttl==0 in reass */
+#define	ICMP_PARAMPROB		12		/* ip header bad */
+#define		ICMP_PARAMPROB_OPTABSENT 1		/* req. opt. absent */
+#define	ICMP_TSTAMP		13		/* timestamp request */
+#define	ICMP_TSTAMPREPLY	14		/* timestamp reply */
+#define	ICMP_IREQ		15		/* information request */
+#define	ICMP_IREQREPLY		16		/* information reply */
+#define	ICMP_MASKREQ		17		/* address mask request */
+#define	ICMP_MASKREPLY		18		/* address mask reply */
+
+#define	ICMP_MAXTYPE		18
+
+#define	ICMP_INFOTYPE(type) \
+	((type) == ICMP_ECHOREPLY || (type) == ICMP_ECHO || \
+	(type) == ICMP_ROUTERADVERT || (type) == ICMP_ROUTERSOLICIT || \
+	(type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \
+	(type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \
+	(type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY)
+
+void icmp_input _P((struct mbuf *, int));
+void icmp_error _P((struct mbuf *, u_char, u_char, int, char *));
+void icmp_reflect _P((struct mbuf *));
+
+#endif
diff --git a/slirp/ip_input.c b/slirp/ip_input.c
new file mode 100644
index 000000000..74b922316
--- /dev/null
+++ b/slirp/ip_input.c
@@ -0,0 +1,697 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
+ * ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP are
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include "ip_icmp.h"
+
+int ip_defttl;
+struct ipstat ipstat;
+struct ipq ipq;
+
+/*
+ * IP initialization: fill in IP protocol switch table.
+ * All protocols not implemented in kernel go to raw IP protocol handler.
+ */
+void
+ip_init()
+{
+	ipq.next = ipq.prev = (ipqp_32)&ipq;
+	ip_id = tt.tv_sec & 0xffff;
+	udp_init();
+	tcp_init();
+	ip_defttl = IPDEFTTL;
+}
+
+/*
+ * Ip input routine.  Checksum and byte swap header.  If fragmented
+ * try to reassemble.  Process options.  Pass to next level.
+ */
+void
+ip_input(m)
+	struct mbuf *m;
+{
+	register struct ip *ip;
+	int hlen;
+	
+	DEBUG_CALL("ip_input");
+	DEBUG_ARG("m = %lx", (long)m);
+	DEBUG_ARG("m_len = %d", m->m_len);
+
+	ipstat.ips_total++;
+	
+	if (m->m_len < sizeof (struct ip)) {
+		ipstat.ips_toosmall++;
+		return;
+	}
+	
+	ip = mtod(m, struct ip *);
+	
+	if (ip->ip_v != IPVERSION) {
+		ipstat.ips_badvers++;
+		goto bad;
+	}
+
+	hlen = ip->ip_hl << 2;
+	if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
+	  ipstat.ips_badhlen++;                     /* or packet too short */
+	  goto bad;
+	}
+
+        /* keep ip header intact for ICMP reply
+	 * ip->ip_sum = cksum(m, hlen); 
+	 * if (ip->ip_sum) { 
+	 */
+	if(cksum(m,hlen)) {
+	  ipstat.ips_badsum++;
+	  goto bad;
+	}
+
+	/*
+	 * Convert fields to host representation.
+	 */
+	NTOHS(ip->ip_len);
+	if (ip->ip_len < hlen) {
+		ipstat.ips_badlen++;
+		goto bad;
+	}
+	NTOHS(ip->ip_id);
+	NTOHS(ip->ip_off);
+
+	/*
+	 * Check that the amount of data in the buffers
+	 * is as at least much as the IP header would have us expect.
+	 * Trim mbufs if longer than we expect.
+	 * Drop packet if shorter than we expect.
+	 */
+	if (m->m_len < ip->ip_len) {
+		ipstat.ips_tooshort++;
+		goto bad;
+	}
+	/* Should drop packet if mbuf too long? hmmm... */
+	if (m->m_len > ip->ip_len)
+	   m_adj(m, ip->ip_len - m->m_len);
+
+	/* check ip_ttl for a correct ICMP reply */
+	if(ip->ip_ttl==0 || ip->ip_ttl==1) {
+	  icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
+	  goto bad;
+	}
+
+	/*
+	 * Process options and, if not destined for us,
+	 * ship it on.  ip_dooptions returns 1 when an
+	 * error was detected (causing an icmp message
+	 * to be sent and the original packet to be freed).
+	 */
+/* We do no IP options */
+/*	if (hlen > sizeof (struct ip) && ip_dooptions(m))
+ *		goto next;
+ */
+	/*
+	 * If offset or IP_MF are set, must reassemble.
+	 * Otherwise, nothing need be done.
+	 * (We could look in the reassembly queue to see
+	 * if the packet was previously fragmented,
+	 * but it's not worth the time; just let them time out.)
+	 * 
+	 * XXX This should fail, don't fragment yet
+	 */
+	if (ip->ip_off &~ IP_DF) {
+	  register struct ipq *fp;
+		/*
+		 * Look for queue of fragments
+		 * of this datagram.
+		 */
+		for (fp = (struct ipq *) ipq.next; fp != &ipq;
+		     fp = (struct ipq *) fp->next)
+		  if (ip->ip_id == fp->ipq_id &&
+		      ip->ip_src.s_addr == fp->ipq_src.s_addr &&
+		      ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
+		      ip->ip_p == fp->ipq_p)
+		    goto found;
+		fp = 0;
+	found:
+
+		/*
+		 * Adjust ip_len to not reflect header,
+		 * set ip_mff if more fragments are expected,
+		 * convert offset of this to bytes.
+		 */
+		ip->ip_len -= hlen;
+		if (ip->ip_off & IP_MF)
+		  ((struct ipasfrag *)ip)->ipf_mff |= 1;
+		else 
+		  ((struct ipasfrag *)ip)->ipf_mff &= ~1;
+
+		ip->ip_off <<= 3;
+
+		/*
+		 * If datagram marked as having more fragments
+		 * or if this is not the first fragment,
+		 * attempt reassembly; if it succeeds, proceed.
+		 */
+		if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) {
+			ipstat.ips_fragments++;
+			ip = ip_reass((struct ipasfrag *)ip, fp);
+			if (ip == 0)
+				return;
+			ipstat.ips_reassembled++;
+			m = dtom(ip);
+		} else
+			if (fp)
+		   	   ip_freef(fp);
+
+	} else
+		ip->ip_len -= hlen;
+
+	/*
+	 * Switch out to protocol's input routine.
+	 */
+	ipstat.ips_delivered++;
+	switch (ip->ip_p) {
+	 case IPPROTO_TCP:
+		tcp_input(m, hlen, (struct socket *)NULL);
+		break;
+	 case IPPROTO_UDP:
+		udp_input(m, hlen);
+		break;
+	 case IPPROTO_ICMP:
+		icmp_input(m, hlen);
+		break;
+	 default:
+		ipstat.ips_noproto++;
+		m_free(m);
+	}
+	return;
+bad:
+	m_freem(m);
+	return;
+}
+
+/*
+ * Take incoming datagram fragment and try to
+ * reassemble it into whole datagram.  If a chain for
+ * reassembly of this datagram already exists, then it
+ * is given as fp; otherwise have to make a chain.
+ */
+struct ip *
+ip_reass(ip, fp)
+	register struct ipasfrag *ip;
+	register struct ipq *fp;
+{
+	register struct mbuf *m = dtom(ip);
+	register struct ipasfrag *q;
+	int hlen = ip->ip_hl << 2;
+	int i, next;
+	
+	DEBUG_CALL("ip_reass");
+	DEBUG_ARG("ip = %lx", (long)ip);
+	DEBUG_ARG("fp = %lx", (long)fp);
+	DEBUG_ARG("m = %lx", (long)m);
+
+	/*
+	 * Presence of header sizes in mbufs
+	 * would confuse code below.
+         * Fragment m_data is concatenated.
+	 */
+	m->m_data += hlen;
+	m->m_len -= hlen;
+
+	/*
+	 * If first fragment to arrive, create a reassembly queue.
+	 */
+	if (fp == 0) {
+	  struct mbuf *t;
+	  if ((t = m_get()) == NULL) goto dropfrag;
+	  fp = mtod(t, struct ipq *);
+	  insque_32(fp, &ipq);
+	  fp->ipq_ttl = IPFRAGTTL;
+	  fp->ipq_p = ip->ip_p;
+	  fp->ipq_id = ip->ip_id;
+	  fp->ipq_next = fp->ipq_prev = (ipasfragp_32)fp;
+	  fp->ipq_src = ((struct ip *)ip)->ip_src;
+	  fp->ipq_dst = ((struct ip *)ip)->ip_dst;
+	  q = (struct ipasfrag *)fp;
+	  goto insert;
+	}
+	
+	/*
+	 * Find a segment which begins after this one does.
+	 */
+	for (q = (struct ipasfrag *)fp->ipq_next; q != (struct ipasfrag *)fp;
+	    q = (struct ipasfrag *)q->ipf_next)
+		if (q->ip_off > ip->ip_off)
+			break;
+
+	/*
+	 * If there is a preceding segment, it may provide some of
+	 * our data already.  If so, drop the data from the incoming
+	 * segment.  If it provides all of our data, drop us.
+	 */
+	if (q->ipf_prev != (ipasfragp_32)fp) {
+		i = ((struct ipasfrag *)(q->ipf_prev))->ip_off +
+		  ((struct ipasfrag *)(q->ipf_prev))->ip_len - ip->ip_off;
+		if (i > 0) {
+			if (i >= ip->ip_len)
+				goto dropfrag;
+			m_adj(dtom(ip), i);
+			ip->ip_off += i;
+			ip->ip_len -= i;
+		}
+	}
+
+	/*
+	 * While we overlap succeeding segments trim them or,
+	 * if they are completely covered, dequeue them.
+	 */
+	while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) {
+		i = (ip->ip_off + ip->ip_len) - q->ip_off;
+		if (i < q->ip_len) {
+			q->ip_len -= i;
+			q->ip_off += i;
+			m_adj(dtom(q), i);
+			break;
+		}
+		q = (struct ipasfrag *) q->ipf_next;
+		m_freem(dtom((struct ipasfrag *) q->ipf_prev));
+		ip_deq((struct ipasfrag *) q->ipf_prev);
+	}
+
+insert:
+	/*
+	 * Stick new segment in its place;
+	 * check for complete reassembly.
+	 */
+	ip_enq(ip, (struct ipasfrag *) q->ipf_prev);
+	next = 0;
+	for (q = (struct ipasfrag *) fp->ipq_next; q != (struct ipasfrag *)fp;
+	     q = (struct ipasfrag *) q->ipf_next) {
+		if (q->ip_off != next)
+			return (0);
+		next += q->ip_len;
+	}
+	if (((struct ipasfrag *)(q->ipf_prev))->ipf_mff & 1)
+		return (0);
+
+	/*
+	 * Reassembly is complete; concatenate fragments.
+	 */
+	q = (struct ipasfrag *) fp->ipq_next;
+	m = dtom(q);
+
+	q = (struct ipasfrag *) q->ipf_next;
+	while (q != (struct ipasfrag *)fp) {
+	  struct mbuf *t;
+	  t = dtom(q);
+	  m_cat(m, t);
+	  q = (struct ipasfrag *) q->ipf_next;
+	}
+
+	/*
+	 * Create header for new ip packet by
+	 * modifying header of first packet;
+	 * dequeue and discard fragment reassembly header.
+	 * Make header visible.
+	 */
+	ip = (struct ipasfrag *) fp->ipq_next;
+
+	/*
+	 * If the fragments concatenated to an mbuf that's
+	 * bigger than the total size of the fragment, then and
+	 * m_ext buffer was alloced. But fp->ipq_next points to
+	 * the old buffer (in the mbuf), so we must point ip
+	 * into the new buffer.
+	 */
+	if (m->m_flags & M_EXT) {
+	  int delta;
+	  delta = (char *)ip - m->m_dat;
+	  ip = (struct ipasfrag *)(m->m_ext + delta);
+	}
+
+	/* DEBUG_ARG("ip = %lx", (long)ip); 
+	 * ip=(struct ipasfrag *)m->m_data; */
+
+	ip->ip_len = next;
+	ip->ipf_mff &= ~1;
+	((struct ip *)ip)->ip_src = fp->ipq_src;
+	((struct ip *)ip)->ip_dst = fp->ipq_dst;
+	remque_32(fp);
+	(void) m_free(dtom(fp));
+	m = dtom(ip);
+	m->m_len += (ip->ip_hl << 2);
+	m->m_data -= (ip->ip_hl << 2);
+
+	return ((struct ip *)ip);
+
+dropfrag:
+	ipstat.ips_fragdropped++;
+	m_freem(m);
+	return (0);
+}
+
+/*
+ * Free a fragment reassembly header and all
+ * associated datagrams.
+ */
+void
+ip_freef(fp)
+	struct ipq *fp;
+{
+	register struct ipasfrag *q, *p;
+
+	for (q = (struct ipasfrag *) fp->ipq_next; q != (struct ipasfrag *)fp;
+	    q = p) {
+		p = (struct ipasfrag *) q->ipf_next;
+		ip_deq(q);
+		m_freem(dtom(q));
+	}
+	remque_32(fp);
+	(void) m_free(dtom(fp));
+}
+
+/*
+ * Put an ip fragment on a reassembly chain.
+ * Like insque, but pointers in middle of structure.
+ */
+void
+ip_enq(p, prev)
+	register struct ipasfrag *p, *prev;
+{
+	DEBUG_CALL("ip_enq");
+	DEBUG_ARG("prev = %lx", (long)prev);
+	p->ipf_prev = (ipasfragp_32) prev;
+	p->ipf_next = prev->ipf_next;
+	((struct ipasfrag *)(prev->ipf_next))->ipf_prev = (ipasfragp_32) p;
+	prev->ipf_next = (ipasfragp_32) p;
+}
+
+/*
+ * To ip_enq as remque is to insque.
+ */
+void
+ip_deq(p)
+	register struct ipasfrag *p;
+{
+	((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;
+	((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;
+}
+
+/*
+ * IP timer processing;
+ * if a timer expires on a reassembly
+ * queue, discard it.
+ */
+void
+ip_slowtimo()
+{
+	register struct ipq *fp;
+	
+	DEBUG_CALL("ip_slowtimo");
+	
+	fp = (struct ipq *) ipq.next;
+	if (fp == 0)
+	   return;
+
+	while (fp != &ipq) {
+		--fp->ipq_ttl;
+		fp = (struct ipq *) fp->next;
+		if (((struct ipq *)(fp->prev))->ipq_ttl == 0) {
+			ipstat.ips_fragtimeout++;
+			ip_freef((struct ipq *) fp->prev);
+		}
+	}
+}
+
+/*
+ * Do option processing on a datagram,
+ * possibly discarding it if bad options are encountered,
+ * or forwarding it if source-routed.
+ * Returns 1 if packet has been forwarded/freed,
+ * 0 if the packet should be processed further.
+ */
+
+#ifdef notdef
+
+int
+ip_dooptions(m)
+	struct mbuf *m;
+{
+	register struct ip *ip = mtod(m, struct ip *);
+	register u_char *cp;
+	register struct ip_timestamp *ipt;
+	register struct in_ifaddr *ia;
+/*	int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; */
+	int opt, optlen, cnt, off, code, type, forward = 0;
+	struct in_addr *sin, dst;
+typedef u_int32_t n_time;
+	n_time ntime;
+
+	dst = ip->ip_dst;
+	cp = (u_char *)(ip + 1);
+	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
+	for (; cnt > 0; cnt -= optlen, cp += optlen) {
+		opt = cp[IPOPT_OPTVAL];
+		if (opt == IPOPT_EOL)
+			break;
+		if (opt == IPOPT_NOP)
+			optlen = 1;
+		else {
+			optlen = cp[IPOPT_OLEN];
+			if (optlen <= 0 || optlen > cnt) {
+				code = &cp[IPOPT_OLEN] - (u_char *)ip;
+				goto bad;
+			}
+		}
+		switch (opt) {
+
+		default:
+			break;
+
+		/*
+		 * Source routing with record.
+		 * Find interface with current destination address.
+		 * If none on this machine then drop if strictly routed,
+		 * or do nothing if loosely routed.
+		 * Record interface address and bring up next address
+		 * component.  If strictly routed make sure next
+		 * address is on directly accessible net.
+		 */
+		case IPOPT_LSRR:
+		case IPOPT_SSRR:
+			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
+				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+				goto bad;
+			}
+			ipaddr.sin_addr = ip->ip_dst;
+			ia = (struct in_ifaddr *)
+				ifa_ifwithaddr((struct sockaddr *)&ipaddr);
+			if (ia == 0) {
+				if (opt == IPOPT_SSRR) {
+					type = ICMP_UNREACH;
+					code = ICMP_UNREACH_SRCFAIL;
+					goto bad;
+				}
+				/*
+				 * Loose routing, and not at next destination
+				 * yet; nothing to do except forward.
+				 */
+				break;
+			}
+			off--;			/ * 0 origin *  /
+			if (off > optlen - sizeof(struct in_addr)) {
+				/*
+				 * End of source route.  Should be for us.
+				 */
+				save_rte(cp, ip->ip_src);
+				break;
+			}
+			/*
+			 * locate outgoing interface
+			 */
+			bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
+			    sizeof(ipaddr.sin_addr));
+			if (opt == IPOPT_SSRR) {
+#define	INA	struct in_ifaddr *
+#define	SA	struct sockaddr *
+ 			    if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
+				ia = (INA)ifa_ifwithnet((SA)&ipaddr);
+			} else
+				ia = ip_rtaddr(ipaddr.sin_addr);
+			if (ia == 0) {
+				type = ICMP_UNREACH;
+				code = ICMP_UNREACH_SRCFAIL;
+				goto bad;
+			}
+			ip->ip_dst = ipaddr.sin_addr;
+			bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
+			    (caddr_t)(cp + off), sizeof(struct in_addr));
+			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+			/*
+			 * Let ip_intr's mcast routing check handle mcast pkts
+			 */
+			forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
+			break;
+
+		case IPOPT_RR:
+			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
+				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+				goto bad;
+			}
+			/*
+			 * If no space remains, ignore.
+			 */
+			off--;			 * 0 origin *
+			if (off > optlen - sizeof(struct in_addr))
+				break;
+			bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
+			    sizeof(ipaddr.sin_addr));
+			/*
+			 * locate outgoing interface; if we're the destination,
+			 * use the incoming interface (should be same).
+			 */
+			if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
+			    (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
+				type = ICMP_UNREACH;
+				code = ICMP_UNREACH_HOST;
+				goto bad;
+			}
+			bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
+			    (caddr_t)(cp + off), sizeof(struct in_addr));
+			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+			break;
+
+		case IPOPT_TS:
+			code = cp - (u_char *)ip;
+			ipt = (struct ip_timestamp *)cp;
+			if (ipt->ipt_len < 5)
+				goto bad;
+			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
+				if (++ipt->ipt_oflw == 0)
+					goto bad;
+				break;
+			}
+			sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
+			switch (ipt->ipt_flg) {
+
+			case IPOPT_TS_TSONLY:
+				break;
+
+			case IPOPT_TS_TSANDADDR:
+				if (ipt->ipt_ptr + sizeof(n_time) +
+				    sizeof(struct in_addr) > ipt->ipt_len)
+					goto bad;
+				ipaddr.sin_addr = dst;
+				ia = (INA)ifaof_ i f p foraddr((SA)&ipaddr,
+							    m->m_pkthdr.rcvif);
+				if (ia == 0)
+					continue;
+				bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
+				    (caddr_t)sin, sizeof(struct in_addr));
+				ipt->ipt_ptr += sizeof(struct in_addr);
+				break;
+
+			case IPOPT_TS_PRESPEC:
+				if (ipt->ipt_ptr + sizeof(n_time) +
+				    sizeof(struct in_addr) > ipt->ipt_len)
+					goto bad;
+				bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
+				    sizeof(struct in_addr));
+				if (ifa_ifwithaddr((SA)&ipaddr) == 0)
+					continue;
+				ipt->ipt_ptr += sizeof(struct in_addr);
+				break;
+
+			default:
+				goto bad;
+			}
+			ntime = iptime();
+			bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
+			    sizeof(n_time));
+			ipt->ipt_ptr += sizeof(n_time);
+		}
+	}
+	if (forward) {
+		ip_forward(m, 1);
+		return (1);
+	}
+		}
+	}
+	return (0);
+bad:
+	/* ip->ip_len -= ip->ip_hl << 2;   XXX icmp_error adds in hdr length */
+
+/* Not yet */
+ 	icmp_error(m, type, code, 0, 0);
+
+	ipstat.ips_badoptions++;
+	return (1);
+}
+
+#endif /* notdef */
+
+/*
+ * Strip out IP options, at higher
+ * level protocol in the kernel.
+ * Second argument is buffer to which options
+ * will be moved, and return value is their length.
+ * (XXX) should be deleted; last arg currently ignored.
+ */
+void
+ip_stripoptions(m, mopt)
+	register struct mbuf *m;
+	struct mbuf *mopt;
+{
+	register int i;
+	struct ip *ip = mtod(m, struct ip *);
+	register caddr_t opts;
+	int olen;
+
+	olen = (ip->ip_hl<<2) - sizeof (struct ip);
+	opts = (caddr_t)(ip + 1);
+	i = m->m_len - (sizeof (struct ip) + olen);
+	memcpy(opts, opts  + olen, (unsigned)i);
+	m->m_len -= olen;
+	
+	ip->ip_hl = sizeof(struct ip) >> 2;
+}
diff --git a/slirp/ip_output.c b/slirp/ip_output.c
new file mode 100644
index 000000000..f3dc9b70e
--- /dev/null
+++ b/slirp/ip_output.c
@@ -0,0 +1,205 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ip_output.c	8.3 (Berkeley) 1/21/94
+ * ip_output.c,v 1.9 1994/11/16 10:17:10 jkh Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP are
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+u_int16_t ip_id;
+
+/*
+ * IP output.  The packet in mbuf chain m contains a skeletal IP
+ * header (with len, off, ttl, proto, tos, src, dst).
+ * The mbuf chain containing the packet will be freed.
+ * The mbuf opt, if present, will not be freed.
+ */
+int
+ip_output(so, m0)
+	struct socket *so;
+	struct mbuf *m0;
+{
+	register struct ip *ip;
+	register struct mbuf *m = m0;
+	register int hlen = sizeof(struct ip );
+	int len, off, error = 0;
+
+	DEBUG_CALL("ip_output");
+	DEBUG_ARG("so = %lx", (long)so);
+	DEBUG_ARG("m0 = %lx", (long)m0);
+	
+	/* We do no options */
+/*	if (opt) {
+ *		m = ip_insertoptions(m, opt, &len);
+ *		hlen = len;
+ *	}
+ */
+	ip = mtod(m, struct ip *);
+	/*
+	 * Fill in IP header.
+	 */
+	ip->ip_v = IPVERSION;
+	ip->ip_off &= IP_DF;
+	ip->ip_id = htons(ip_id++);
+	ip->ip_hl = hlen >> 2;
+	ipstat.ips_localout++;
+
+	/*
+	 * Verify that we have any chance at all of being able to queue
+	 *      the packet or packet fragments
+	 */
+	/* XXX Hmmm... */
+/*	if (if_queued > if_thresh && towrite <= 0) {
+ *		error = ENOBUFS;
+ *		goto bad;
+ *	}
+ */
+	
+	/*
+	 * If small enough for interface, can just send directly.
+	 */
+	if ((u_int16_t)ip->ip_len <= if_mtu) {
+		ip->ip_len = htons((u_int16_t)ip->ip_len);
+		ip->ip_off = htons((u_int16_t)ip->ip_off);
+		ip->ip_sum = 0;
+		ip->ip_sum = cksum(m, hlen);
+
+		if_output(so, m);
+		goto done;
+	}
+
+	/*
+	 * Too large for interface; fragment if possible.
+	 * Must be able to put at least 8 bytes per fragment.
+	 */
+	if (ip->ip_off & IP_DF) {
+		error = -1;
+		ipstat.ips_cantfrag++;
+		goto bad;
+	}
+	
+	len = (if_mtu - hlen) &~ 7;       /* ip databytes per packet */
+	if (len < 8) {
+		error = -1;
+		goto bad;
+	}
+
+    {
+	int mhlen, firstlen = len;
+	struct mbuf **mnext = &m->m_nextpkt;
+
+	/*
+	 * Loop through length of segment after first fragment,
+	 * make new header and copy data of each part and link onto chain.
+	 */
+	m0 = m;
+	mhlen = sizeof (struct ip);
+	for (off = hlen + len; off < (u_int16_t)ip->ip_len; off += len) {
+	  register struct ip *mhip;
+	  m = m_get();
+	  if (m == 0) {
+	    error = -1;
+	    ipstat.ips_odropped++;
+	    goto sendorfree;
+	  }
+	  m->m_data += if_maxlinkhdr;
+	  mhip = mtod(m, struct ip *);
+	  *mhip = *ip;
+		
+		/* No options */
+/*		if (hlen > sizeof (struct ip)) {
+ *			mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
+ *			mhip->ip_hl = mhlen >> 2;
+ *		}
+ */
+	  m->m_len = mhlen;
+	  mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
+	  if (ip->ip_off & IP_MF)
+	    mhip->ip_off |= IP_MF;
+	  if (off + len >= (u_int16_t)ip->ip_len)
+	    len = (u_int16_t)ip->ip_len - off;
+	  else 
+	    mhip->ip_off |= IP_MF;
+	  mhip->ip_len = htons((u_int16_t)(len + mhlen));
+	  
+	  if (m_copy(m, m0, off, len) < 0) {
+	    error = -1;
+	    goto sendorfree;
+	  }
+	  
+	  mhip->ip_off = htons((u_int16_t)mhip->ip_off);
+	  mhip->ip_sum = 0;
+	  mhip->ip_sum = cksum(m, mhlen);
+	  *mnext = m;
+	  mnext = &m->m_nextpkt;
+	  ipstat.ips_ofragments++;
+	}
+	/*
+	 * Update first fragment by trimming what's been copied out
+	 * and updating header, then send each fragment (in order).
+	 */
+	m = m0;
+	m_adj(m, hlen + firstlen - (u_int16_t)ip->ip_len);
+	ip->ip_len = htons((u_int16_t)m->m_len);
+	ip->ip_off = htons((u_int16_t)(ip->ip_off | IP_MF));
+	ip->ip_sum = 0;
+	ip->ip_sum = cksum(m, hlen);
+sendorfree:
+	for (m = m0; m; m = m0) {
+		m0 = m->m_nextpkt;
+		m->m_nextpkt = 0;
+		if (error == 0)
+			if_output(so, m);
+		else
+			m_freem(m);
+	}
+
+	if (error == 0)
+		ipstat.ips_fragmented++;
+    }
+
+done:
+	return (error);
+
+bad:
+	m_freem(m0);
+	goto done;
+}
diff --git a/slirp/libslirp.h b/slirp/libslirp.h
new file mode 100644
index 000000000..31ddaea4d
--- /dev/null
+++ b/slirp/libslirp.h
@@ -0,0 +1,19 @@
+#ifndef _LIBSLIRP_H
+#define _LIBSLIRP_H
+
+#include <sys/select.h>
+
+void slirp_init(void);
+
+void slirp_select_fill(int *pnfds, 
+                       fd_set *readfds, fd_set *writefds, fd_set *xfds);
+
+void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds);
+
+void slirp_input(const uint8_t *pkt, int pkt_len);
+
+/* you must provide the following functions: */
+int slirp_can_output(void);
+void slirp_output(const uint8_t *pkt, int pkt_len);
+
+#endif
diff --git a/slirp/main.h b/slirp/main.h
new file mode 100644
index 000000000..dc06d6fe7
--- /dev/null
+++ b/slirp/main.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
+#define TOWRITEMAX 512
+#define min(x,y) ((x) < (y) ? (x) : (y))
+
+extern struct timeval tt;
+extern int link_up;
+extern int slirp_socket;
+extern int slirp_socket_unit;
+extern int slirp_socket_port;
+extern u_int32_t slirp_socket_addr;
+extern char *slirp_socket_passwd;
+extern int ctty_closed;
+
+/*
+ * Get the difference in 2 times from updtim()
+ * Allow for wraparound times, "just in case"
+ * x is the greater of the 2 (current time) and y is
+ * what it's being compared against.
+ */
+#define TIME_DIFF(x,y) (x)-(y) < 0 ? ~0-(y)+(x) : (x)-(y)
+
+extern char *slirp_tty;
+extern char *exec_shell;
+extern u_int curtime;
+extern fd_set *global_readfds, *global_writefds, *global_xfds;
+extern struct in_addr ctl_addr;
+extern struct in_addr special_addr;
+extern struct in_addr our_addr;
+extern struct in_addr loopback_addr;
+extern struct in_addr dns_addr;
+extern char *username;
+extern char *socket_path;
+extern int towrite_max;
+extern int ppp_exit;
+extern int so_options;
+extern int tcp_keepintvl;
+extern uint8_t client_ethaddr[6];
+
+#define PROTO_SLIP 0x1
+#ifdef USE_PPP
+#define PROTO_PPP 0x2
+#endif
+
+void if_encap(const uint8_t *ip_data, int ip_data_len);
diff --git a/slirp/mbuf.c b/slirp/mbuf.c
new file mode 100644
index 000000000..fa36d8950
--- /dev/null
+++ b/slirp/mbuf.c
@@ -0,0 +1,245 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+/*
+ * mbuf's in SLiRP are much simpler than the real mbufs in
+ * FreeBSD.  They are fixed size, determined by the MTU,
+ * so that one whole packet can fit.  Mbuf's cannot be
+ * chained together.  If there's more data than the mbuf
+ * could hold, an external malloced buffer is pointed to
+ * by m_ext (and the data pointers) and M_EXT is set in
+ * the flags
+ */
+
+#include <slirp.h>
+
+struct	mbuf *mbutl;
+char	*mclrefcnt;
+int mbuf_alloced = 0;
+struct mbuf m_freelist, m_usedlist;
+int mbuf_thresh = 30;
+int mbuf_max = 0;
+int msize;
+
+void
+m_init()
+{
+	m_freelist.m_next = m_freelist.m_prev = &m_freelist;
+	m_usedlist.m_next = m_usedlist.m_prev = &m_usedlist;
+	msize_init();
+}
+
+void
+msize_init()
+{
+	/*
+	 * Find a nice value for msize
+	 * XXX if_maxlinkhdr already in mtu
+	 */
+	msize = (if_mtu>if_mru?if_mtu:if_mru) + 
+			if_maxlinkhdr + sizeof(struct m_hdr ) + 6;
+}
+
+/*
+ * Get an mbuf from the free list, if there are none
+ * malloc one
+ * 
+ * Because fragmentation can occur if we alloc new mbufs and
+ * free old mbufs, we mark all mbufs above mbuf_thresh as M_DOFREE,
+ * which tells m_free to actually free() it
+ */
+struct mbuf *
+m_get()
+{
+	register struct mbuf *m;
+	int flags = 0;
+	
+	DEBUG_CALL("m_get");
+	
+	if (m_freelist.m_next == &m_freelist) {
+		m = (struct mbuf *)malloc(msize);
+		if (m == NULL) goto end_error;
+		mbuf_alloced++;
+		if (mbuf_alloced > mbuf_thresh)
+			flags = M_DOFREE;
+		if (mbuf_alloced > mbuf_max)
+			mbuf_max = mbuf_alloced;
+	} else {
+		m = m_freelist.m_next;
+		remque(m);
+	}
+	
+	/* Insert it in the used list */
+	insque(m,&m_usedlist);
+	m->m_flags = (flags | M_USEDLIST);
+	
+	/* Initialise it */
+	m->m_size = msize - sizeof(struct m_hdr);
+	m->m_data = m->m_dat;
+	m->m_len = 0;
+	m->m_nextpkt = 0;
+	m->m_prevpkt = 0;
+end_error:
+	DEBUG_ARG("m = %lx", (long )m);
+	return m;
+}
+
+void
+m_free(m)
+	struct mbuf *m;
+{
+	
+  DEBUG_CALL("m_free");
+  DEBUG_ARG("m = %lx", (long )m);
+	
+  if(m) {
+	/* Remove from m_usedlist */
+	if (m->m_flags & M_USEDLIST)
+	   remque(m);
+	
+	/* If it's M_EXT, free() it */
+	if (m->m_flags & M_EXT)
+	   free(m->m_ext);
+
+	/*
+	 * Either free() it or put it on the free list
+	 */
+	if (m->m_flags & M_DOFREE) {
+		free(m);
+		mbuf_alloced--;
+	} else if ((m->m_flags & M_FREELIST) == 0) {
+		insque(m,&m_freelist);
+		m->m_flags = M_FREELIST; /* Clobber other flags */
+	}
+  } /* if(m) */
+}
+
+/*
+ * Copy data from one mbuf to the end of
+ * the other.. if result is too big for one mbuf, malloc()
+ * an M_EXT data segment
+ */
+void
+m_cat(m, n)
+	register struct mbuf *m, *n;
+{
+	/*
+	 * If there's no room, realloc
+	 */
+	if (M_FREEROOM(m) < n->m_len)
+		m_inc(m,m->m_size+MINCSIZE);
+	
+	memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
+	m->m_len += n->m_len;
+
+	m_free(n);
+}
+
+
+/* make m size bytes large */
+void
+m_inc(m, size)
+        struct mbuf *m;
+        int size;
+{
+	/* some compiles throw up on gotos.  This one we can fake. */
+        if(m->m_size>size) return;
+
+        if (m->m_flags & M_EXT) {
+	  /* datasize = m->m_data - m->m_ext; */
+	  m->m_ext = (char *)realloc(m->m_ext,size);
+/*		if (m->m_ext == NULL)
+ *			return (struct mbuf *)NULL;
+ */		
+	  /* m->m_data = m->m_ext + datasize; */
+        } else {
+	  int datasize;
+	  char *dat;
+	  datasize = m->m_data - m->m_dat;
+	  dat = (char *)malloc(size);
+/*		if (dat == NULL)
+ *			return (struct mbuf *)NULL;
+ */
+	  memcpy(dat, m->m_dat, m->m_size);
+	  
+	  m->m_ext = dat;
+	  m->m_data = m->m_ext + datasize;
+	  m->m_flags |= M_EXT;
+        }
+ 
+        m->m_size = size;
+
+}
+
+
+
+void
+m_adj(m, len)
+	struct mbuf *m;
+	int len;
+{
+	if (m == NULL)
+		return;
+	if (len >= 0) {
+		/* Trim from head */
+		m->m_data += len;
+		m->m_len -= len;
+	} else {
+		/* Trim from tail */
+		len = -len;
+		m->m_len -= len;
+	}
+}
+
+
+/*
+ * Copy len bytes from m, starting off bytes into n
+ */
+int
+m_copy(n, m, off, len)
+	struct mbuf *n, *m;
+	int off, len;
+{
+	if (len > M_FREEROOM(n))
+		return -1;
+
+	memcpy((n->m_data + n->m_len), (m->m_data + off), len);
+	n->m_len += len;
+	return 0;
+}
+
+
+/*
+ * Given a pointer into an mbuf, return the mbuf
+ * XXX This is a kludge, I should eliminate the need for it
+ * Fortunately, it's not used often
+ */
+struct mbuf *
+dtom(dat)
+	void *dat;
+{
+	struct mbuf *m;
+	
+	DEBUG_CALL("dtom");
+	DEBUG_ARG("dat = %lx", (long )dat);
+
+	/* bug corrected for M_EXT buffers */
+	for (m = m_usedlist.m_next; m != &m_usedlist; m = m->m_next) {
+	  if (m->m_flags & M_EXT) {
+	    if( (char *)dat>=m->m_ext && (char *)dat<(m->m_ext + m->m_size) )
+	      return m;
+	  } else {
+	    if( (char *)dat >= m->m_dat && (char *)dat<(m->m_dat + m->m_size) )
+	      return m;
+	  }
+	}
+	
+	DEBUG_ERROR((dfd, "dtom failed"));
+	
+	return (struct mbuf *)0;
+}
+
diff --git a/slirp/mbuf.h b/slirp/mbuf.h
new file mode 100644
index 000000000..8cc292bbf
--- /dev/null
+++ b/slirp/mbuf.h
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)mbuf.h	8.3 (Berkeley) 1/21/94
+ * mbuf.h,v 1.9 1994/11/14 13:54:20 bde Exp
+ */
+
+#ifndef _MBUF_H_
+#define _MBUF_H_
+
+#define m_freem m_free
+
+
+#define MINCSIZE 4096	/* Amount to increase mbuf if too small */
+
+/*
+ * Macros for type conversion
+ * mtod(m,t) -	convert mbuf pointer to data pointer of correct type
+ * dtom(x) -	convert data pointer within mbuf to mbuf pointer (XXX)
+ */
+#define mtod(m,t)	((t)(m)->m_data)
+/* #define	dtom(x)		((struct mbuf *)((int)(x) & ~(M_SIZE-1))) */
+
+/* XXX About mbufs for slirp:
+ * Only one mbuf is ever used in a chain, for each "cell" of data.
+ * m_nextpkt points to the next packet, if fragmented.
+ * If the data is too large, the M_EXT is used, and a larger block
+ * is alloced.  Therefore, m_free[m] must check for M_EXT and if set
+ * free the m_ext.  This is inefficient memory-wise, but who cares.
+ */
+
+/* XXX should union some of these! */
+/* header at beginning of each mbuf: */
+struct m_hdr {
+	struct	mbuf *mh_next;		/* Linked list of mbufs */
+	struct	mbuf *mh_prev;
+	struct	mbuf *mh_nextpkt;	/* Next packet in queue/record */
+	struct	mbuf *mh_prevpkt; /* Flags aren't used in the output queue */
+	int	mh_flags;	  /* Misc flags */
+
+	int	mh_size;		/* Size of data */
+	struct	socket *mh_so;
+	
+	caddr_t	mh_data;		/* Location of data */
+	int	mh_len;			/* Amount of data in this mbuf */
+};
+
+/* 
+ * How much room is in the mbuf, from m_data to the end of the mbuf
+ */
+#define M_ROOM(m) ((m->m_flags & M_EXT)? \
+			(((m)->m_ext + (m)->m_size) - (m)->m_data) \
+		   : \
+			(((m)->m_dat + (m)->m_size) - (m)->m_data))
+
+/*
+ * How much free room there is
+ */
+#define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
+#define M_TRAILINGSPACE M_FREEROOM
+
+struct mbuf {
+	struct	m_hdr m_hdr;
+	union M_dat {
+		char	m_dat_[1]; /* ANSI don't like 0 sized arrays */
+		char	*m_ext_;
+	} M_dat;
+};
+
+#define m_next		m_hdr.mh_next
+#define m_prev		m_hdr.mh_prev
+#define m_nextpkt	m_hdr.mh_nextpkt
+#define m_prevpkt	m_hdr.mh_prevpkt
+#define m_flags		m_hdr.mh_flags
+#define	m_len		m_hdr.mh_len
+#define	m_data		m_hdr.mh_data
+#define m_size		m_hdr.mh_size
+#define m_dat		M_dat.m_dat_
+#define m_ext		M_dat.m_ext_
+#define m_so		m_hdr.mh_so
+
+#define ifq_prev m_prev
+#define ifq_next m_next
+#define ifs_prev m_prevpkt
+#define ifs_next m_nextpkt
+#define ifq_so m_so
+
+#define M_EXT			0x01	/* m_ext points to more (malloced) data */
+#define M_FREELIST		0x02	/* mbuf is on free list */
+#define M_USEDLIST		0x04	/* XXX mbuf is on used list (for dtom()) */
+#define M_DOFREE		0x08	/* when m_free is called on the mbuf, free()
+					 * it rather than putting it on the free list */
+
+/*
+ * Mbuf statistics. XXX
+ */
+
+struct mbstat {
+	int mbs_alloced;		/* Number of mbufs allocated */
+	
+};
+
+extern struct	mbstat mbstat;
+extern int mbuf_alloced;
+extern struct mbuf m_freelist, m_usedlist;
+extern int mbuf_max;
+
+void m_init _P((void));
+void msize_init _P((void));
+struct mbuf * m_get _P((void));
+void m_free _P((struct mbuf *));
+void m_cat _P((register struct mbuf *, register struct mbuf *));
+void m_inc _P((struct mbuf *, int));
+void m_adj _P((struct mbuf *, int));
+int m_copy _P((struct mbuf *, struct mbuf *, int, int));
+struct mbuf * dtom _P((void *));
+
+#endif
diff --git a/slirp/misc.c b/slirp/misc.c
new file mode 100644
index 000000000..7f6448dff
--- /dev/null
+++ b/slirp/misc.c
@@ -0,0 +1,925 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#define WANT_SYS_IOCTL_H
+#include <slirp.h>
+
+u_int curtime, time_fasttimo, last_slowtimo, detach_time;
+u_int detach_wait = 600000;	/* 10 minutes */
+
+#if 0
+int x_port = -1;
+int x_display = 0;
+int x_screen = 0;
+
+int
+show_x(buff, inso)
+	char *buff;
+	struct socket *inso;
+{
+	if (x_port < 0) {
+		lprint("X Redir: X not being redirected.\r\n");
+	} else {
+		lprint("X Redir: In sh/bash/zsh/etc. type: DISPLAY=%s:%d.%d; export DISPLAY\r\n",
+		      inet_ntoa(our_addr), x_port, x_screen);
+		lprint("X Redir: In csh/tcsh/etc. type:    setenv DISPLAY %s:%d.%d\r\n",
+		      inet_ntoa(our_addr), x_port, x_screen);
+		if (x_display)
+		   lprint("X Redir: Redirecting to display %d\r\n", x_display);
+	}
+	
+	return CFG_OK;
+}
+
+
+/*
+ * XXX Allow more than one X redirection?
+ */
+void
+redir_x(inaddr, start_port, display, screen)
+	u_int32_t inaddr;
+	int start_port;
+	int display;
+	int screen;
+{
+	int i;
+	
+	if (x_port >= 0) {
+		lprint("X Redir: X already being redirected.\r\n");
+		show_x(0, 0);
+	} else {
+		for (i = 6001 + (start_port-1); i <= 6100; i++) {
+			if (solisten(htons(i), inaddr, htons(6000 + display), 0)) {
+				/* Success */
+				x_port = i - 6000;
+				x_display = display;
+				x_screen = screen;
+				show_x(0, 0);
+				return;
+			}
+		}
+		lprint("X Redir: Error: Couldn't redirect a port for X. Weird.\r\n");
+	}
+}
+#endif
+
+#ifndef HAVE_INET_ATON
+int
+inet_aton(cp, ia)
+	const char *cp;
+	struct in_addr *ia;
+{
+	u_int32_t addr = inet_addr(cp);
+	if (addr == 0xffffffff)
+		return 0;
+	ia->s_addr = addr;
+	return 1;
+}
+#endif
+
+/*
+ * Get our IP address and put it in our_addr
+ */
+void
+getouraddr()
+{
+	char buff[256];
+	struct hostent *he;
+	
+	if (gethostname(buff,256) < 0)
+	   return;
+	
+	if ((he = gethostbyname(buff)) == NULL)
+	   return;
+	
+	our_addr = *(struct in_addr *)he->h_addr;
+}
+
+#if SIZEOF_CHAR_P == 8
+
+struct quehead_32 {
+	u_int32_t qh_link;
+	u_int32_t qh_rlink;
+};
+
+inline void
+insque_32(a, b)
+	void *a;
+	void *b;
+{
+	register struct quehead_32 *element = (struct quehead_32 *) a;
+	register struct quehead_32 *head = (struct quehead_32 *) b;
+	element->qh_link = head->qh_link;
+	head->qh_link = (u_int32_t)element;
+	element->qh_rlink = (u_int32_t)head;
+	((struct quehead_32 *)(element->qh_link))->qh_rlink
+	= (u_int32_t)element;
+}
+
+inline void
+remque_32(a)
+	void *a;
+{
+	register struct quehead_32 *element = (struct quehead_32 *) a;
+	((struct quehead_32 *)(element->qh_link))->qh_rlink = element->qh_rlink;
+	((struct quehead_32 *)(element->qh_rlink))->qh_link = element->qh_link;
+	element->qh_rlink = 0;
+}
+
+#endif /* SIZEOF_CHAR_P == 8 */
+
+struct quehead {
+	struct quehead *qh_link;
+	struct quehead *qh_rlink;
+};
+
+inline void
+insque(a, b)
+	void *a, *b;
+{
+	register struct quehead *element = (struct quehead *) a;
+	register struct quehead *head = (struct quehead *) b;
+	element->qh_link = head->qh_link;
+	head->qh_link = (struct quehead *)element;
+	element->qh_rlink = (struct quehead *)head;
+	((struct quehead *)(element->qh_link))->qh_rlink
+	= (struct quehead *)element;
+}
+
+inline void
+remque(a)
+     void *a;
+{
+  register struct quehead *element = (struct quehead *) a;
+  ((struct quehead *)(element->qh_link))->qh_rlink = element->qh_rlink;
+  ((struct quehead *)(element->qh_rlink))->qh_link = element->qh_link;
+  element->qh_rlink = NULL;
+  /*  element->qh_link = NULL;  TCP FIN1 crashes if you do this.  Why ? */
+}
+
+/* #endif */
+
+
+int
+add_exec(ex_ptr, do_pty, exec, addr, port)
+	struct ex_list **ex_ptr;
+	int do_pty;
+	char *exec;
+	int addr;
+	int port;
+{
+	struct ex_list *tmp_ptr;
+	
+	/* First, check if the port is "bound" */
+	for (tmp_ptr = *ex_ptr; tmp_ptr; tmp_ptr = tmp_ptr->ex_next) {
+		if (port == tmp_ptr->ex_fport && addr == tmp_ptr->ex_addr)
+		   return -1;
+	}
+	
+	tmp_ptr = *ex_ptr;
+	*ex_ptr = (struct ex_list *)malloc(sizeof(struct ex_list));
+	(*ex_ptr)->ex_fport = port;
+	(*ex_ptr)->ex_addr = addr;
+	(*ex_ptr)->ex_pty = do_pty;
+	(*ex_ptr)->ex_exec = strdup(exec);
+	(*ex_ptr)->ex_next = tmp_ptr;
+	return 0;
+}
+
+#ifndef HAVE_STRERROR
+
+/*
+ * For systems with no strerror
+ */
+
+extern int sys_nerr;
+extern char *sys_errlist[];
+
+char *
+strerror(error)
+	int error;
+{
+	if (error < sys_nerr)
+	   return sys_errlist[error];
+	else
+	   return "Unknown error.";
+}
+
+#endif
+
+
+#if 0
+int
+openpty(amaster, aslave)
+	int *amaster, *aslave;
+{
+	register int master, slave;
+
+#ifdef HAVE_GRANTPT
+	char *ptr;
+	
+	if ((master = open("/dev/ptmx", O_RDWR)) < 0 ||
+	    grantpt(master) < 0 ||
+	    unlockpt(master) < 0 ||
+	    (ptr = ptsname(master)) == NULL)  {
+		close(master);
+		return -1;
+	}
+	
+	if ((slave = open(ptr, O_RDWR)) < 0 ||
+	    ioctl(slave, I_PUSH, "ptem") < 0 ||
+	    ioctl(slave, I_PUSH, "ldterm") < 0 ||
+	    ioctl(slave, I_PUSH, "ttcompat") < 0) {
+		close(master);
+		close(slave);
+		return -1;
+	}
+	
+	*amaster = master;
+	*aslave = slave;
+	return 0;
+	
+#else
+	
+	static char line[] = "/dev/ptyXX";
+	register const char *cp1, *cp2;
+	
+	for (cp1 = "pqrsPQRS"; *cp1; cp1++) {
+		line[8] = *cp1;
+		for (cp2 = "0123456789abcdefghijklmnopqrstuv"; *cp2; cp2++) {
+			line[9] = *cp2;
+			if ((master = open(line, O_RDWR, 0)) == -1) {
+				if (errno == ENOENT)
+				   return (-1);    /* out of ptys */
+			} else {
+				line[5] = 't';
+				/* These will fail */
+				(void) chown(line, getuid(), 0);
+				(void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP);
+#ifdef HAVE_REVOKE
+				(void) revoke(line);
+#endif
+				if ((slave = open(line, O_RDWR, 0)) != -1) {
+					*amaster = master;
+					*aslave = slave;
+					return 0;
+				}
+				(void) close(master);
+				line[5] = 'p';
+			}
+		}
+	}
+	errno = ENOENT; /* out of ptys */
+	return (-1);
+#endif
+}
+
+/*
+ * XXX This is ugly
+ * We create and bind a socket, then fork off to another
+ * process, which connects to this socket, after which we
+ * exec the wanted program.  If something (strange) happens,
+ * the accept() call could block us forever.
+ * 
+ * do_pty = 0   Fork/exec inetd style
+ * do_pty = 1   Fork/exec using slirp.telnetd
+ * do_ptr = 2   Fork/exec using pty
+ */
+int
+fork_exec(so, ex, do_pty)
+	struct socket *so;
+	char *ex;
+	int do_pty;
+{
+	int s;
+	struct sockaddr_in addr;
+	int addrlen = sizeof(addr);
+	int opt;
+        int master;
+	char *argv[256];
+	char buff[256];
+	/* don't want to clobber the original */
+	char *bptr;
+	char *curarg;
+	int c, i;
+	
+	DEBUG_CALL("fork_exec");
+	DEBUG_ARG("so = %lx", (long)so);
+	DEBUG_ARG("ex = %lx", (long)ex);
+	DEBUG_ARG("do_pty = %lx", (long)do_pty);
+	
+	if (do_pty == 2) {
+		if (openpty(&master, &s) == -1) {
+			lprint("Error: openpty failed: %s\n", strerror(errno));
+			return 0;
+		}
+	} else {
+		addr.sin_family = AF_INET;
+		addr.sin_port = 0;
+		addr.sin_addr.s_addr = INADDR_ANY;
+		
+		if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0 ||
+		    bind(s, (struct sockaddr *)&addr, addrlen) < 0 ||
+		    listen(s, 1) < 0) {
+			lprint("Error: inet socket: %s\n", strerror(errno));
+			close(s);
+			
+			return 0;
+		}
+	}
+	
+	switch(fork()) {
+	 case -1:
+		lprint("Error: fork failed: %s\n", strerror(errno));
+		close(s);
+		if (do_pty == 2)
+		   close(master);
+		return 0;
+		
+	 case 0:
+		/* Set the DISPLAY */
+		if (do_pty == 2) {
+			(void) close(master);
+#ifdef TIOCSCTTY /* XXXXX */
+			(void) setsid();
+			ioctl(s, TIOCSCTTY, (char *)NULL);
+#endif
+		} else {
+			getsockname(s, (struct sockaddr *)&addr, &addrlen);
+			close(s);
+			/*
+			 * Connect to the socket
+			 * XXX If any of these fail, we're in trouble!
+	 		 */
+			s = socket(AF_INET, SOCK_STREAM, 0);
+			addr.sin_addr = loopback_addr;
+			connect(s, (struct sockaddr *)&addr, addrlen);
+		}
+		
+		if (x_port >= 0) {
+#ifdef HAVE_SETENV
+			sprintf(buff, "%s:%d.%d", inet_ntoa(our_addr), x_port, x_screen);
+			setenv("DISPLAY", buff, 1);
+#else
+			sprintf(buff, "DISPLAY=%s:%d.%d", inet_ntoa(our_addr), x_port, x_screen);
+			putenv(buff);
+#endif
+		}
+	
+		dup2(s, 0);
+		dup2(s, 1);
+		dup2(s, 2);
+		for (s = 3; s <= 255; s++)
+		   close(s);
+		
+		i = 0;
+		bptr = strdup(ex); /* No need to free() this */
+		if (do_pty == 1) {
+			/* Setup "slirp.telnetd -x" */
+			argv[i++] = "slirp.telnetd";
+			argv[i++] = "-x";
+			argv[i++] = bptr;
+		} else
+		   do {
+			/* Change the string into argv[] */
+			curarg = bptr;
+			while (*bptr != ' ' && *bptr != (char)0)
+			   bptr++;
+			c = *bptr;
+			*bptr++ = (char)0;
+			argv[i++] = strdup(curarg);
+		   } while (c);
+		
+		argv[i] = 0;
+		execvp(argv[0], argv);
+		
+		/* Ooops, failed, let's tell the user why */
+		  {
+			  char buff[256];
+			  
+			  sprintf(buff, "Error: execvp of %s failed: %s\n", 
+				  argv[0], strerror(errno));
+			  write(2, buff, strlen(buff)+1);
+		  }
+		close(0); close(1); close(2); /* XXX */
+		exit(1);
+		
+	 default:
+		if (do_pty == 2) {
+			close(s);
+			so->s = master;
+		} else {
+			/*
+			 * XXX this could block us...
+			 * XXX Should set a timer here, and if accept() doesn't
+		 	 * return after X seconds, declare it a failure
+		 	 * The only reason this will block forever is if socket()
+		 	 * of connect() fail in the child process
+		 	 */
+			so->s = accept(s, (struct sockaddr *)&addr, &addrlen);
+			close(s);
+			opt = 1;
+			setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
+			opt = 1;
+			setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int));
+		}
+		fd_nonblock(so->s);
+		
+		/* Append the telnet options now */
+		if (so->so_m != 0 && do_pty == 1)  {
+			sbappend(so, so->so_m);
+			so->so_m = 0;
+		}
+		
+		return 1;
+	}
+}
+#endif
+
+#ifndef HAVE_STRDUP
+char *
+strdup(str)
+	const char *str;
+{
+	char *bptr;
+	
+	bptr = (char *)malloc(strlen(str)+1);
+	strcpy(bptr, str);
+	
+	return bptr;
+}
+#endif
+
+#if 0
+void
+snooze_hup(num)
+	int num;
+{
+	int s, ret;
+#ifndef NO_UNIX_SOCKETS
+	struct sockaddr_un sock_un;
+#endif
+	struct sockaddr_in sock_in;
+	char buff[256];
+	
+	ret = -1;
+	if (slirp_socket_passwd) {
+		s = socket(AF_INET, SOCK_STREAM, 0);
+		if (s < 0)
+		   slirp_exit(1);
+		sock_in.sin_family = AF_INET;
+		sock_in.sin_addr.s_addr = slirp_socket_addr;
+		sock_in.sin_port = htons(slirp_socket_port);
+		if (connect(s, (struct sockaddr *)&sock_in, sizeof(sock_in)) != 0)
+		   slirp_exit(1); /* just exit...*/
+		sprintf(buff, "kill %s:%d", slirp_socket_passwd, slirp_socket_unit);
+		write(s, buff, strlen(buff)+1);
+	}
+#ifndef NO_UNIX_SOCKETS
+	  else {
+		s = socket(AF_UNIX, SOCK_STREAM, 0);
+		if (s < 0)
+		   slirp_exit(1);
+		sock_un.sun_family = AF_UNIX;
+		strcpy(sock_un.sun_path, socket_path);
+		if (connect(s, (struct sockaddr *)&sock_un,
+			      sizeof(sock_un.sun_family) + sizeof(sock_un.sun_path)) != 0)
+		   slirp_exit(1);
+		sprintf(buff, "kill none:%d", slirp_socket_unit);
+		write(s, buff, strlen(buff)+1);
+	}
+#endif
+	slirp_exit(0);
+}
+	
+	
+void
+snooze()
+{
+	sigset_t s;
+	int i;
+	
+	/* Don't need our data anymore */
+	/* XXX This makes SunOS barf */
+/*	brk(0); */
+	
+	/* Close all fd's */
+	for (i = 255; i >= 0; i--)
+	   close(i);
+	
+	signal(SIGQUIT, slirp_exit);
+	signal(SIGHUP, snooze_hup);
+	sigemptyset(&s);
+	
+	/* Wait for any signal */
+	sigsuspend(&s);
+	
+	/* Just in case ... */
+	exit(255);
+}
+
+void
+relay(s)
+	int s;
+{
+	char buf[8192];
+	int n;
+	fd_set readfds;
+	struct ttys *ttyp;
+	
+	/* Don't need our data anymore */
+	/* XXX This makes SunOS barf */
+/*	brk(0); */
+	
+	signal(SIGQUIT, slirp_exit);
+	signal(SIGHUP, slirp_exit);
+        signal(SIGINT, slirp_exit);
+	signal(SIGTERM, slirp_exit);
+	
+	/* Fudge to get term_raw and term_restore to work */
+	if (NULL == (ttyp = tty_attach (0, slirp_tty))) {
+         lprint ("Error: tty_attach failed in misc.c:relay()\r\n");
+         slirp_exit (1);
+    }
+	ttyp->fd = 0;
+	ttyp->flags |= TTY_CTTY;
+	term_raw(ttyp);
+	
+	while (1) {
+		FD_ZERO(&readfds);
+		
+		FD_SET(0, &readfds);
+		FD_SET(s, &readfds);
+		
+		n = select(s+1, &readfds, (fd_set *)0, (fd_set *)0, (struct timeval *)0);
+		
+		if (n <= 0)
+		   slirp_exit(0);
+		
+		if (FD_ISSET(0, &readfds)) {
+			n = read(0, buf, 8192);
+			if (n <= 0)
+			   slirp_exit(0);
+			n = writen(s, buf, n);
+			if (n <= 0)
+			   slirp_exit(0);
+		}
+		
+		if (FD_ISSET(s, &readfds)) {
+			n = read(s, buf, 8192);
+			if (n <= 0)
+			   slirp_exit(0);
+			n = writen(0, buf, n);
+			if (n <= 0)
+			   slirp_exit(0);
+		}
+	}
+	
+	/* Just in case.... */
+	exit(1);
+}
+#endif
+
+int (*lprint_print) _P((void *, const char *, va_list));
+char *lprint_ptr, *lprint_ptr2, **lprint_arg;
+
+void
+#ifdef __STDC__
+lprint(const char *format, ...)
+#else
+lprint(va_alist) va_dcl
+#endif
+{
+	va_list args;
+        
+#ifdef __STDC__
+        va_start(args, format);
+#else
+        char *format;
+        va_start(args);
+        format = va_arg(args, char *);
+#endif
+#if 0
+	/* If we're printing to an sbuf, make sure there's enough room */
+	/* XXX +100? */
+	if (lprint_sb) {
+		if ((lprint_ptr - lprint_sb->sb_wptr) >=
+		    (lprint_sb->sb_datalen - (strlen(format) + 100))) {
+			int deltaw = lprint_sb->sb_wptr - lprint_sb->sb_data;
+			int deltar = lprint_sb->sb_rptr - lprint_sb->sb_data;
+			int deltap = lprint_ptr -         lprint_sb->sb_data;
+			                        
+			lprint_sb->sb_data = (char *)realloc(lprint_sb->sb_data,
+							     lprint_sb->sb_datalen + TCP_SNDSPACE);
+			
+			/* Adjust all values */
+			lprint_sb->sb_wptr = lprint_sb->sb_data + deltaw;
+			lprint_sb->sb_rptr = lprint_sb->sb_data + deltar;
+			lprint_ptr =         lprint_sb->sb_data + deltap;
+			
+			lprint_sb->sb_datalen += TCP_SNDSPACE;
+		}
+	}
+#endif	
+	if (lprint_print)
+	   lprint_ptr += (*lprint_print)(*lprint_arg, format, args);
+	
+	/* Check if they want output to be logged to file as well */
+	if (lfd) {
+		/* 
+		 * Remove \r's
+		 * otherwise you'll get ^M all over the file
+		 */
+		int len = strlen(format);
+		char *bptr1, *bptr2;
+		
+		bptr1 = bptr2 = strdup(format);
+		
+		while (len--) {
+			if (*bptr1 == '\r')
+			   memcpy(bptr1, bptr1+1, len+1);
+			else
+			   bptr1++;
+		}
+		vfprintf(lfd, bptr2, args);
+		free(bptr2);
+	}
+	va_end(args);
+}
+
+void
+add_emu(buff)
+	char *buff;
+{
+	u_int lport, fport;
+	u_int8_t tos = 0, emu = 0;
+	char buff1[256], buff2[256], buff4[128];
+	char *buff3 = buff4;
+	struct emu_t *emup;
+	struct socket *so;
+	
+	if (sscanf(buff, "%256s %256s", buff2, buff1) != 2) {
+		lprint("Error: Bad arguments\r\n");
+		return;
+	}
+	
+	if (sscanf(buff1, "%d:%d", &lport, &fport) != 2) {
+		lport = 0;
+		if (sscanf(buff1, "%d", &fport) != 1) {
+			lprint("Error: Bad first argument\r\n");
+			return;
+		}
+	}
+	
+	if (sscanf(buff2, "%128[^:]:%128s", buff1, buff3) != 2) {
+		buff3 = 0;
+		if (sscanf(buff2, "%256s", buff1) != 1) {
+			lprint("Error: Bad second argument\r\n");
+			return;
+		}
+	}
+	
+	if (buff3) {
+		if (strcmp(buff3, "lowdelay") == 0)
+		   tos = IPTOS_LOWDELAY;
+		else if (strcmp(buff3, "throughput") == 0)
+		   tos = IPTOS_THROUGHPUT;
+		else {
+			lprint("Error: Expecting \"lowdelay\"/\"throughput\"\r\n");
+			return;
+		}
+	}
+	
+	if (strcmp(buff1, "ftp") == 0)
+	   emu = EMU_FTP;
+	else if (strcmp(buff1, "irc") == 0)
+	   emu = EMU_IRC;
+	else if (strcmp(buff1, "none") == 0)
+	   emu = EMU_NONE; /* ie: no emulation */
+	else {
+		lprint("Error: Unknown service\r\n");
+		return;
+	}
+	
+	/* First, check that it isn't already emulated */
+	for (emup = tcpemu; emup; emup = emup->next) {
+		if (emup->lport == lport && emup->fport == fport) {
+			lprint("Error: port already emulated\r\n");
+			return;
+		}
+	}
+	
+	/* link it */
+	emup = (struct emu_t *)malloc(sizeof (struct emu_t));
+	emup->lport = (u_int16_t)lport;
+	emup->fport = (u_int16_t)fport;
+	emup->tos = tos;
+	emup->emu = emu;
+	emup->next = tcpemu;
+	tcpemu = emup;
+	
+	/* And finally, mark all current sessions, if any, as being emulated */
+	for (so = tcb.so_next; so != &tcb; so = so->so_next) {
+		if ((lport && lport == ntohs(so->so_lport)) ||
+		    (fport && fport == ntohs(so->so_fport))) {
+			if (emu)
+			   so->so_emu = emu;
+			if (tos)
+			   so->so_iptos = tos;
+		}
+	}
+	
+	lprint("Adding emulation for %s to port %d/%d\r\n", buff1, emup->lport, emup->fport);
+}
+
+#ifdef BAD_SPRINTF
+
+#undef vsprintf
+#undef sprintf
+
+/*
+ * Some BSD-derived systems have a sprintf which returns char *
+ */
+
+int
+vsprintf_len(string, format, args)
+	char *string;
+	const char *format;
+	va_list args;
+{
+	vsprintf(string, format, args);
+	return strlen(string);
+}
+
+int
+#ifdef __STDC__
+sprintf_len(char *string, const char *format, ...)
+#else
+sprintf_len(va_alist) va_dcl
+#endif
+{
+	va_list args;
+#ifdef __STDC__
+	va_start(args, format);
+#else
+	char *string;
+	char *format;
+	va_start(args);
+	string = va_arg(args, char *);
+	format = va_arg(args, char *);
+#endif
+	vsprintf(string, format, args);
+	return strlen(string);
+}
+
+#endif
+
+void
+u_sleep(usec)
+	int usec;
+{
+	struct timeval t;
+	fd_set fdset;
+	
+	FD_ZERO(&fdset);
+	
+	t.tv_sec = 0;
+	t.tv_usec = usec * 1000;
+	
+	select(0, &fdset, &fdset, &fdset, &t);
+}
+
+/*
+ * Set fd blocking and non-blocking
+ */
+
+void
+fd_nonblock(fd)
+	int fd;
+{
+#ifdef FIONBIO
+	int opt = 1;
+	
+	ioctl(fd, FIONBIO, &opt);
+#else
+	int opt;
+	
+	opt = fcntl(fd, F_GETFL, 0);
+	opt |= O_NONBLOCK;
+	fcntl(fd, F_SETFL, opt);
+#endif
+}
+
+void
+fd_block(fd)
+	int fd;
+{
+#ifdef FIONBIO
+	int opt = 0;
+	
+	ioctl(fd, FIONBIO, &opt);
+#else
+	int opt;
+	
+	opt = fcntl(fd, F_GETFL, 0);
+	opt &= ~O_NONBLOCK;
+	fcntl(fd, F_SETFL, opt);
+#endif
+}
+
+
+#if 0
+/*
+ * invoke RSH
+ */
+int
+rsh_exec(so,ns, user, host, args)
+	struct socket *so;
+	struct socket *ns;
+	char *user;
+	char *host;
+	char *args;
+{
+	int fd[2];
+	int fd0[2];
+	int s;
+	char buff[256];
+	
+	DEBUG_CALL("rsh_exec");
+	DEBUG_ARG("so = %lx", (long)so);
+	
+	if (pipe(fd)<0) {
+          lprint("Error: pipe failed: %s\n", strerror(errno));
+          return 0;
+	}
+/* #ifdef HAVE_SOCKETPAIR */
+#if 1
+        if (socketpair(PF_UNIX,SOCK_STREAM,0, fd0) == -1) {
+          close(fd[0]);
+          close(fd[1]);
+          lprint("Error: openpty failed: %s\n", strerror(errno));
+          return 0;
+        }
+#else
+        if (openpty(&fd0[0], &fd0[1]) == -1) {
+          close(fd[0]);
+          close(fd[1]);
+          lprint("Error: openpty failed: %s\n", strerror(errno));
+          return 0;
+        }
+#endif
+	
+	switch(fork()) {
+	 case -1:
+           lprint("Error: fork failed: %s\n", strerror(errno));
+           close(fd[0]);
+           close(fd[1]);
+           close(fd0[0]);
+           close(fd0[1]);
+           return 0;
+           
+	 case 0:
+           close(fd[0]);
+           close(fd0[0]);
+           
+		/* Set the DISPLAY */
+           if (x_port >= 0) {
+#ifdef HAVE_SETENV
+             sprintf(buff, "%s:%d.%d", inet_ntoa(our_addr), x_port, x_screen);
+             setenv("DISPLAY", buff, 1);
+#else
+             sprintf(buff, "DISPLAY=%s:%d.%d", inet_ntoa(our_addr), x_port, x_screen);
+             putenv(buff);
+#endif
+           }
+           
+           dup2(fd0[1], 0);
+           dup2(fd0[1], 1);
+           dup2(fd[1], 2);
+           for (s = 3; s <= 255; s++)
+             close(s);
+           
+           execlp("rsh","rsh","-l", user, host, args, NULL);
+           
+           /* Ooops, failed, let's tell the user why */
+           
+           sprintf(buff, "Error: execlp of %s failed: %s\n", 
+                   "rsh", strerror(errno));
+           write(2, buff, strlen(buff)+1);
+           close(0); close(1); close(2); /* XXX */
+           exit(1);
+           
+        default:
+          close(fd[1]);
+          close(fd0[1]);
+          ns->s=fd[0];
+          so->s=fd0[0];
+          
+          return 1;
+	}
+}
+#endif
diff --git a/slirp/misc.h b/slirp/misc.h
new file mode 100644
index 000000000..8e2819b99
--- /dev/null
+++ b/slirp/misc.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#ifndef _MISC_H_
+#define _MISC_H_
+
+struct ex_list {
+	int ex_pty;			/* Do we want a pty? */
+	int ex_addr;			/* The last byte of the address */
+	int ex_fport;                   /* Port to telnet to */
+	char *ex_exec;                  /* Command line of what to exec */
+	struct ex_list *ex_next;
+};
+
+extern struct ex_list *exec_list;
+extern u_int curtime, time_fasttimo, last_slowtimo, detach_time, detach_wait;
+
+extern int (*lprint_print) _P((void *, const char *, va_list));
+extern char *lprint_ptr, *lprint_ptr2, **lprint_arg;
+extern struct sbuf *lprint_sb;
+
+#ifndef HAVE_STRDUP
+char *strdup _P((const char *));
+#endif
+
+void do_wait _P((int));
+
+#define EMU_NONE 0x0
+
+/* TCP emulations */
+#define EMU_CTL 0x1
+#define EMU_FTP 0x2
+#define EMU_KSH 0x3
+#define EMU_IRC 0x4
+#define EMU_REALAUDIO 0x5
+#define EMU_RLOGIN 0x6
+#define EMU_IDENT 0x7
+#define EMU_RSH 0x8
+
+#define EMU_NOCONNECT 0x10	/* Don't connect */
+
+/* UDP emulations */
+#define EMU_TALK	0x1
+#define EMU_NTALK	0x2
+#define EMU_CUSEEME	0x3
+
+struct tos_t {
+	u_int16_t lport;
+	u_int16_t fport;
+	u_int8_t tos;
+	u_int8_t emu;
+};
+
+struct emu_t {
+	u_int16_t lport;
+	u_int16_t fport;
+	u_int8_t tos;
+	u_int8_t emu;
+	struct emu_t *next;
+};
+
+extern struct emu_t *tcpemu;
+
+extern int x_port, x_server, x_display;
+
+int show_x _P((char *, struct socket *));
+void redir_x _P((u_int32_t, int, int, int));
+void getouraddr _P((void));
+inline  void slirp_insque  _P((void *, void *));
+inline  void slirp_remque  _P((void *));
+int add_exec _P((struct ex_list **, int, char *, int, int));
+int openpty _P((int *, int *));
+int fork_exec _P((struct socket *, char *, int));
+void snooze_hup _P((int));
+void snooze _P((void));
+void relay _P((int));
+void add_emu _P((char *));
+void u_sleep _P((int));
+void fd_nonblock _P((int));
+void fd_block _P((int));
+int rsh_exec _P((struct socket *, struct socket *, char *, char *, char *));
+
+#endif
diff --git a/slirp/sbuf.c b/slirp/sbuf.c
new file mode 100644
index 000000000..04fb97ddc
--- /dev/null
+++ b/slirp/sbuf.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+/* Done as a macro in socket.h */
+/* int
+ * sbspace(struct sockbuff *sb) 
+ * {
+ *	return SB_DATALEN - sb->sb_cc;
+ * }
+ */
+
+void
+sbfree(sb)
+	struct sbuf *sb;
+{
+	free(sb->sb_data);
+}
+
+void
+sbdrop(sb, num)
+	struct sbuf *sb;
+	int num; 
+{
+	/* 
+	 * We can only drop how much we have
+	 * This should never succeed 
+	 */
+	if(num > sb->sb_cc)
+		num = sb->sb_cc;
+	sb->sb_cc -= num;
+	sb->sb_rptr += num;
+	if(sb->sb_rptr >= sb->sb_data + sb->sb_datalen)
+		sb->sb_rptr -= sb->sb_datalen;
+   
+}
+
+void
+sbreserve(sb, size)
+	struct sbuf *sb;
+	int size;
+{
+	if (sb->sb_data) {
+		/* Already alloced, realloc if necessary */
+		if (sb->sb_datalen != size) {
+			sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)realloc(sb->sb_data, size);
+			sb->sb_cc = 0;
+			if (sb->sb_wptr)
+			   sb->sb_datalen = size;
+			else
+			   sb->sb_datalen = 0;
+		}
+	} else {
+		sb->sb_wptr = sb->sb_rptr = sb->sb_data = (char *)malloc(size);
+		sb->sb_cc = 0;
+		if (sb->sb_wptr)
+		   sb->sb_datalen = size;
+		else
+		   sb->sb_datalen = 0;
+	}
+}
+
+/*
+ * Try and write() to the socket, whatever doesn't get written
+ * append to the buffer... for a host with a fast net connection,
+ * this prevents an unnecessary copy of the data
+ * (the socket is non-blocking, so we won't hang)
+ */
+void
+sbappend(so, m)
+	struct socket *so;
+	struct mbuf *m;
+{
+	int ret = 0;
+	
+	DEBUG_CALL("sbappend");
+	DEBUG_ARG("so = %lx", (long)so);
+	DEBUG_ARG("m = %lx", (long)m);
+	DEBUG_ARG("m->m_len = %d", m->m_len);
+	
+	/* Shouldn't happen, but...  e.g. foreign host closes connection */
+	if (m->m_len <= 0) {
+		m_free(m);
+		return;
+	}
+	
+	/*
+	 * If there is urgent data, call sosendoob
+	 * if not all was sent, sowrite will take care of the rest
+	 * (The rest of this function is just an optimisation)
+	 */
+	if (so->so_urgc) {
+		sbappendsb(&so->so_rcv, m);
+		m_free(m);
+		sosendoob(so);
+		return;
+	}
+	
+	/*
+	 * We only write if there's nothing in the buffer,
+	 * ottherwise it'll arrive out of order, and hence corrupt
+	 */
+	if (!so->so_rcv.sb_cc)
+	   ret = write(so->s, m->m_data, m->m_len);
+	
+	if (ret <= 0) {
+		/* 
+		 * Nothing was written
+		 * It's possible that the socket has closed, but
+		 * we don't need to check because if it has closed,
+		 * it will be detected in the normal way by soread()
+		 */
+		sbappendsb(&so->so_rcv, m);
+	} else if (ret != m->m_len) {
+		/*
+		 * Something was written, but not everything..
+		 * sbappendsb the rest
+		 */
+		m->m_len -= ret;
+		m->m_data += ret;
+		sbappendsb(&so->so_rcv, m);
+	} /* else */
+	/* Whatever happened, we free the mbuf */
+	m_free(m);
+}
+
+/*
+ * Copy the data from m into sb
+ * The caller is responsible to make sure there's enough room
+ */
+void
+sbappendsb(sb, m)
+	 struct sbuf *sb;
+	 struct mbuf *m;
+{
+	int len, n,  nn;
+	
+	len = m->m_len;
+
+	if (sb->sb_wptr < sb->sb_rptr) {
+		n = sb->sb_rptr - sb->sb_wptr;
+		if (n > len) n = len;
+		memcpy(sb->sb_wptr, m->m_data, n);
+	} else {
+		/* Do the right edge first */
+		n = sb->sb_data + sb->sb_datalen - sb->sb_wptr;
+		if (n > len) n = len;
+		memcpy(sb->sb_wptr, m->m_data, n);
+		len -= n;
+		if (len) {
+			/* Now the left edge */
+			nn = sb->sb_rptr - sb->sb_data;
+			if (nn > len) nn = len;
+			memcpy(sb->sb_data,m->m_data+n,nn);
+			n += nn;
+		}
+	}
+
+	sb->sb_cc += n;
+	sb->sb_wptr += n;
+	if (sb->sb_wptr >= sb->sb_data + sb->sb_datalen)
+		sb->sb_wptr -= sb->sb_datalen;
+}
+
+/*
+ * Copy data from sbuf to a normal, straight buffer
+ * Don't update the sbuf rptr, this will be
+ * done in sbdrop when the data is acked
+ */
+void
+sbcopy(sb, off, len, to)
+	struct sbuf *sb;
+	int off;
+	int len;
+	char *to;
+{
+	char *from;
+	
+	from = sb->sb_rptr + off;
+	if (from >= sb->sb_data + sb->sb_datalen)
+		from -= sb->sb_datalen;
+
+	if (from < sb->sb_wptr) {
+		if (len > sb->sb_cc) len = sb->sb_cc;
+		memcpy(to,from,len);
+	} else {
+		/* re-use off */
+		off = (sb->sb_data + sb->sb_datalen) - from;
+		if (off > len) off = len;
+		memcpy(to,from,off);
+		len -= off;
+		if (len)
+		   memcpy(to+off,sb->sb_data,len);
+	}
+}
+		
diff --git a/slirp/sbuf.h b/slirp/sbuf.h
new file mode 100644
index 000000000..161e0bb76
--- /dev/null
+++ b/slirp/sbuf.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#ifndef _SBUF_H_
+#define _SBUF_H_
+
+#define sbflush(sb) sbdrop((sb),(sb)->sb_cc)
+#define sbspace(sb) ((sb)->sb_datalen - (sb)->sb_cc)
+
+struct sbuf {
+	u_int	sb_cc;		/* actual chars in buffer */
+	u_int	sb_datalen;	/* Length of data  */
+	char	*sb_wptr;	/* write pointer. points to where the next
+				 * bytes should be written in the sbuf */
+	char	*sb_rptr;	/* read pointer. points to where the next
+				 * byte should be read from the sbuf */
+	char	*sb_data;	/* Actual data */
+};
+
+void sbfree _P((struct sbuf *));
+void sbdrop _P((struct sbuf *, int));
+void sbreserve _P((struct sbuf *, int));
+void sbappend _P((struct socket *, struct mbuf *));
+void sbappendsb _P((struct sbuf *, struct mbuf *));
+void sbcopy _P((struct sbuf *, int, int, char *));
+
+#endif
diff --git a/slirp/slirp.c b/slirp/slirp.c
new file mode 100644
index 000000000..48b45a39c
--- /dev/null
+++ b/slirp/slirp.c
@@ -0,0 +1,550 @@
+#include "slirp.h"
+
+/* host address */
+struct in_addr our_addr;
+/* host dns address */
+struct in_addr dns_addr;
+/* host loopback address */
+struct in_addr loopback_addr;
+
+/* address for slirp virtual addresses */
+struct in_addr special_addr;
+
+const uint8_t special_ethaddr[6] = { 
+    0x52, 0x54, 0x00, 0x12, 0x35, 0x00
+};
+
+uint8_t client_ethaddr[6];
+
+int do_slowtimo;
+int link_up;
+struct timeval tt;
+FILE *lfd;
+
+/* XXX: suppress those select globals */
+fd_set *global_readfds, *global_writefds, *global_xfds;
+
+#ifdef _WIN32
+
+static int get_dns_addr(struct in_addr *pdns_addr)
+{
+    /* XXX: add it */
+    return -1;
+}
+
+#else
+
+static int get_dns_addr(struct in_addr *pdns_addr)
+{
+    char buff[512];
+    char buff2[256];
+    FILE *f;
+    int found = 0;
+    struct in_addr tmp_addr;
+    
+    f = fopen("/etc/resolv.conf", "r");
+    if (!f)
+        return -1;
+
+    lprint("IP address of your DNS(s): ");
+    while (fgets(buff, 512, f) != NULL) {
+        if (sscanf(buff, "nameserver%*[ \t]%256s", buff2) == 1) {
+            if (!inet_aton(buff2, &tmp_addr))
+                continue;
+            if (tmp_addr.s_addr == loopback_addr.s_addr)
+                tmp_addr = our_addr;
+            /* If it's the first one, set it to dns_addr */
+            if (!found)
+                *pdns_addr = tmp_addr;
+            else
+                lprint(", ");
+            if (++found > 3) {
+                lprint("(more)");
+                break;
+            } else
+                lprint("%s", inet_ntoa(tmp_addr));
+        }
+    }
+    if (!found)
+        return -1;
+    return 0;
+}
+
+#endif
+
+void slirp_init(void)
+{
+    debug_init("/tmp/slirp.log", DEBUG_DEFAULT);
+
+    link_up = 1;
+
+    if_init();
+    ip_init();
+
+    /* Initialise mbufs *after* setting the MTU */
+    m_init();
+
+    /* set default addresses */
+    getouraddr();
+    inet_aton("127.0.0.1", &loopback_addr);
+
+    if (get_dns_addr(&dns_addr) < 0) {
+        fprintf(stderr, "Could not get DNS address\n");
+        exit(1);
+    }
+
+    inet_aton(CTL_SPECIAL, &special_addr);
+}
+
+#define CONN_CANFSEND(so) (((so)->so_state & (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
+#define CONN_CANFRCV(so) (((so)->so_state & (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
+#define UPD_NFDS(x) if (nfds < (x)) nfds = (x)
+
+/*
+ * curtime kept to an accuracy of 1ms
+ */
+static void updtime(void)
+{
+	gettimeofday(&tt, 0);
+	
+	curtime = (u_int)tt.tv_sec * (u_int)1000;
+	curtime += (u_int)tt.tv_usec / (u_int)1000;
+	
+	if ((tt.tv_usec % 1000) >= 500)
+	   curtime++;
+}
+
+void slirp_select_fill(int *pnfds, 
+                       fd_set *readfds, fd_set *writefds, fd_set *xfds)
+{
+    struct socket *so, *so_next;
+    struct timeval timeout;
+    int nfds;
+    int tmp_time;
+
+    /* fail safe */
+    global_readfds = NULL;
+    global_writefds = NULL;
+    global_xfds = NULL;
+    
+    nfds = *pnfds;
+	/*
+	 * First, TCP sockets
+	 */
+	do_slowtimo = 0;
+	if (link_up) {
+		/* 
+		 * *_slowtimo needs calling if there are IP fragments
+		 * in the fragment queue, or there are TCP connections active
+		 */
+		do_slowtimo = ((tcb.so_next != &tcb) ||
+			       ((struct ipasfrag *)&ipq != (struct ipasfrag *)ipq.next));
+		
+		for (so = tcb.so_next; so != &tcb; so = so_next) {
+			so_next = so->so_next;
+			
+			/*
+			 * See if we need a tcp_fasttimo
+			 */
+			if (time_fasttimo == 0 && so->so_tcpcb->t_flags & TF_DELACK)
+			   time_fasttimo = curtime; /* Flag when we want a fasttimo */
+			
+			/*
+			 * NOFDREF can include still connecting to local-host,
+			 * newly socreated() sockets etc. Don't want to select these.
+	 		 */
+			if (so->so_state & SS_NOFDREF || so->s == -1)
+			   continue;
+			
+			/*
+			 * Set for reading sockets which are accepting
+			 */
+			if (so->so_state & SS_FACCEPTCONN) {
+                                FD_SET(so->s, readfds);
+				UPD_NFDS(so->s);
+				continue;
+			}
+			
+			/*
+			 * Set for writing sockets which are connecting
+			 */
+			if (so->so_state & SS_ISFCONNECTING) {
+				FD_SET(so->s, writefds);
+				UPD_NFDS(so->s);
+				continue;
+			}
+			
+			/*
+			 * Set for writing if we are connected, can send more, and
+			 * we have something to send
+			 */
+			if (CONN_CANFSEND(so) && so->so_rcv.sb_cc) {
+				FD_SET(so->s, writefds);
+				UPD_NFDS(so->s);
+			}
+			
+			/*
+			 * Set for reading (and urgent data) if we are connected, can
+			 * receive more, and we have room for it XXX /2 ?
+			 */
+			if (CONN_CANFRCV(so) && (so->so_snd.sb_cc < (so->so_snd.sb_datalen/2))) {
+				FD_SET(so->s, readfds);
+				FD_SET(so->s, xfds);
+				UPD_NFDS(so->s);
+			}
+		}
+		
+		/*
+		 * UDP sockets
+		 */
+		for (so = udb.so_next; so != &udb; so = so_next) {
+			so_next = so->so_next;
+			
+			/*
+			 * See if it's timed out
+			 */
+			if (so->so_expire) {
+				if (so->so_expire <= curtime) {
+					udp_detach(so);
+					continue;
+				} else
+					do_slowtimo = 1; /* Let socket expire */
+			}
+			
+			/*
+			 * When UDP packets are received from over the
+			 * link, they're sendto()'d straight away, so
+			 * no need for setting for writing
+			 * Limit the number of packets queued by this session
+			 * to 4.  Note that even though we try and limit this
+			 * to 4 packets, the session could have more queued
+			 * if the packets needed to be fragmented
+			 * (XXX <= 4 ?)
+			 */
+			if ((so->so_state & SS_ISFCONNECTED) && so->so_queued <= 4) {
+				FD_SET(so->s, readfds);
+				UPD_NFDS(so->s);
+			}
+		}
+	}
+	
+	/*
+	 * Setup timeout to use minimum CPU usage, especially when idle
+	 */
+	
+	/* 
+	 * First, see the timeout needed by *timo
+	 */
+	timeout.tv_sec = 0;
+	timeout.tv_usec = -1;
+	/*
+	 * If a slowtimo is needed, set timeout to 500ms from the last
+	 * slow timeout. If a fast timeout is needed, set timeout within
+	 * 200ms of when it was requested.
+	 */
+	if (do_slowtimo) {
+		/* XXX + 10000 because some select()'s aren't that accurate */
+		timeout.tv_usec = ((500 - (curtime - last_slowtimo)) * 1000) + 10000;
+		if (timeout.tv_usec < 0)
+		   timeout.tv_usec = 0;
+		else if (timeout.tv_usec > 510000)
+		   timeout.tv_usec = 510000;
+		
+		/* Can only fasttimo if we also slowtimo */
+		if (time_fasttimo) {
+			tmp_time = (200 - (curtime - time_fasttimo)) * 1000;
+			if (tmp_time < 0)
+			   tmp_time = 0;
+			
+			/* Choose the smallest of the 2 */
+			if (tmp_time < timeout.tv_usec)
+			   timeout.tv_usec = (u_int)tmp_time;
+		}
+	}
+        *pnfds = nfds;
+}	
+
+void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds)
+{
+    struct socket *so, *so_next;
+    int ret;
+
+    global_readfds = readfds;
+    global_writefds = writefds;
+    global_xfds = xfds;
+
+	/* Update time */
+	updtime();
+	
+	/*
+	 * See if anything has timed out 
+	 */
+	if (link_up) {
+		if (time_fasttimo && ((curtime - time_fasttimo) >= 199)) {
+			tcp_fasttimo();
+			time_fasttimo = 0;
+		}
+		if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) {
+			ip_slowtimo();
+			tcp_slowtimo();
+			last_slowtimo = curtime;
+		}
+	}
+	
+	/*
+	 * Check sockets
+	 */
+	if (link_up) {
+		/*
+		 * Check TCP sockets
+		 */
+		for (so = tcb.so_next; so != &tcb; so = so_next) {
+			so_next = so->so_next;
+			
+			/*
+			 * FD_ISSET is meaningless on these sockets
+			 * (and they can crash the program)
+			 */
+			if (so->so_state & SS_NOFDREF || so->s == -1)
+			   continue;
+			
+			/*
+			 * Check for URG data
+			 * This will soread as well, so no need to
+			 * test for readfds below if this succeeds
+			 */
+			if (FD_ISSET(so->s, xfds))
+			   sorecvoob(so);
+			/*
+			 * Check sockets for reading
+			 */
+			else if (FD_ISSET(so->s, readfds)) {
+				/*
+				 * Check for incoming connections
+				 */
+				if (so->so_state & SS_FACCEPTCONN) {
+					tcp_connect(so);
+					continue;
+				} /* else */
+				ret = soread(so);
+				
+				/* Output it if we read something */
+				if (ret > 0)
+				   tcp_output(sototcpcb(so));
+			}
+			
+			/*
+			 * Check sockets for writing
+			 */
+			if (FD_ISSET(so->s, writefds)) {
+			  /*
+			   * Check for non-blocking, still-connecting sockets
+			   */
+			  if (so->so_state & SS_ISFCONNECTING) {
+			    /* Connected */
+			    so->so_state &= ~SS_ISFCONNECTING;
+			    
+			    ret = write(so->s, &ret, 0);
+			    if (ret < 0) {
+			      /* XXXXX Must fix, zero bytes is a NOP */
+			      if (errno == EAGAIN || errno == EWOULDBLOCK ||
+				  errno == EINPROGRESS || errno == ENOTCONN)
+				continue;
+			      
+			      /* else failed */
+			      so->so_state = SS_NOFDREF;
+			    }
+			    /* else so->so_state &= ~SS_ISFCONNECTING; */
+			    
+			    /*
+			     * Continue tcp_input
+			     */
+			    tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);
+			    /* continue; */
+			  } else
+			    ret = sowrite(so);
+			  /*
+			   * XXXXX If we wrote something (a lot), there 
+			   * could be a need for a window update.
+			   * In the worst case, the remote will send
+			   * a window probe to get things going again
+			   */
+			}
+			
+			/*
+			 * Probe a still-connecting, non-blocking socket
+			 * to check if it's still alive
+	 	 	 */
+#ifdef PROBE_CONN
+			if (so->so_state & SS_ISFCONNECTING) {
+			  ret = read(so->s, (char *)&ret, 0);
+			  
+			  if (ret < 0) {
+			    /* XXX */
+			    if (errno == EAGAIN || errno == EWOULDBLOCK ||
+				errno == EINPROGRESS || errno == ENOTCONN)
+			      continue; /* Still connecting, continue */
+			    
+			    /* else failed */
+			    so->so_state = SS_NOFDREF;
+			    
+			    /* tcp_input will take care of it */
+			  } else {
+			    ret = write(so->s, &ret, 0);
+			    if (ret < 0) {
+			      /* XXX */
+			      if (errno == EAGAIN || errno == EWOULDBLOCK ||
+				  errno == EINPROGRESS || errno == ENOTCONN)
+				continue;
+			      /* else failed */
+			      so->so_state = SS_NOFDREF;
+			    } else
+			      so->so_state &= ~SS_ISFCONNECTING;
+			    
+			  }
+			  tcp_input((struct mbuf *)NULL, sizeof(struct ip),so);
+			} /* SS_ISFCONNECTING */
+#endif
+		}
+		
+		/*
+		 * Now UDP sockets.
+		 * Incoming packets are sent straight away, they're not buffered.
+		 * Incoming UDP data isn't buffered either.
+		 */
+		for (so = udb.so_next; so != &udb; so = so_next) {
+			so_next = so->so_next;
+			
+			if (so->s != -1 && FD_ISSET(so->s, readfds)) {
+                            sorecvfrom(so);
+                        }
+		}
+	}
+	
+	/*
+	 * See if we can start outputting
+	 */
+	if (if_queued && link_up)
+	   if_start();
+}
+
+#define ETH_ALEN 6
+#define ETH_HLEN 14
+
+#define ETH_P_IP	0x0800		/* Internet Protocol packet	*/
+#define ETH_P_ARP	0x0806		/* Address Resolution packet	*/
+
+#define	ARPOP_REQUEST	1		/* ARP request			*/
+#define	ARPOP_REPLY	2		/* ARP reply			*/
+
+struct ethhdr 
+{
+	unsigned char	h_dest[ETH_ALEN];	/* destination eth addr	*/
+	unsigned char	h_source[ETH_ALEN];	/* source ether addr	*/
+	unsigned short	h_proto;		/* packet type ID field	*/
+};
+
+struct arphdr
+{
+	unsigned short	ar_hrd;		/* format of hardware address	*/
+	unsigned short	ar_pro;		/* format of protocol address	*/
+	unsigned char	ar_hln;		/* length of hardware address	*/
+	unsigned char	ar_pln;		/* length of protocol address	*/
+	unsigned short	ar_op;		/* ARP opcode (command)		*/
+
+	 /*
+	  *	 Ethernet looks like this : This bit is variable sized however...
+	  */
+	unsigned char		ar_sha[ETH_ALEN];	/* sender hardware address	*/
+	unsigned char		ar_sip[4];		/* sender IP address		*/
+	unsigned char		ar_tha[ETH_ALEN];	/* target hardware address	*/
+	unsigned char		ar_tip[4];		/* target IP address		*/
+};
+
+void arp_input(const uint8_t *pkt, int pkt_len)
+{
+    struct ethhdr *eh = (struct ethhdr *)pkt;
+    struct arphdr *ah = (struct arphdr *)(pkt + ETH_HLEN);
+    uint8_t arp_reply[ETH_HLEN + sizeof(struct arphdr)];
+    struct ethhdr *reh = (struct ethhdr *)arp_reply;
+    struct arphdr *rah = (struct arphdr *)(arp_reply + ETH_HLEN);
+    int ar_op;
+
+    ar_op = ntohs(ah->ar_op);
+    switch(ar_op) {
+    case ARPOP_REQUEST:
+        if (!memcmp(ah->ar_tip, &special_addr, 3) &&
+            (ah->ar_tip[3] == CTL_DNS || ah->ar_tip[3] == CTL_ALIAS)) {
+
+            /* XXX: make an ARP request to have the client address */
+            memcpy(client_ethaddr, eh->h_source, ETH_ALEN);
+
+            /* ARP request for alias/dns mac address */
+            memcpy(reh->h_dest, pkt + ETH_ALEN, ETH_ALEN);
+            memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 1);
+            reh->h_source[5] = ah->ar_tip[3];
+            reh->h_proto = htons(ETH_P_ARP);
+
+            rah->ar_hrd = htons(1);
+            rah->ar_pro = htons(ETH_P_IP);
+            rah->ar_hln = ETH_ALEN;
+            rah->ar_pln = 4;
+            rah->ar_op = htons(ARPOP_REPLY);
+            memcpy(rah->ar_sha, reh->h_source, ETH_ALEN);
+            memcpy(rah->ar_sip, ah->ar_tip, 4);
+            memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN);
+            memcpy(rah->ar_tip, ah->ar_sip, 4);
+            slirp_output(arp_reply, sizeof(arp_reply));
+        }
+        break;
+    default:
+        break;
+    }
+}
+
+void slirp_input(const uint8_t *pkt, int pkt_len)
+{
+    struct mbuf *m;
+    int proto;
+
+    if (pkt_len < ETH_HLEN)
+        return;
+    
+    proto = ntohs(*(uint16_t *)(pkt + 12));
+    switch(proto) {
+    case ETH_P_ARP:
+        arp_input(pkt, pkt_len);
+        break;
+    case ETH_P_IP:
+        m = m_get();
+        if (!m)
+            return;
+        m->m_len = pkt_len;
+        memcpy(m->m_data, pkt, pkt_len);
+
+        m->m_data += ETH_HLEN;
+        m->m_len -= ETH_HLEN;
+
+        ip_input(m);
+        break;
+    default:
+        break;
+    }
+}
+
+/* output the IP packet to the ethernet device */
+void if_encap(const uint8_t *ip_data, int ip_data_len)
+{
+    uint8_t buf[1600];
+    struct ethhdr *eh = (struct ethhdr *)buf;
+
+    if (ip_data_len + ETH_HLEN > sizeof(buf))
+        return;
+
+    memcpy(eh->h_dest, client_ethaddr, ETH_ALEN);
+    memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1);
+    eh->h_source[5] = CTL_ALIAS;
+    eh->h_proto = htons(ETH_P_IP);
+    memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len);
+    slirp_output(buf, ip_data_len + ETH_HLEN);
+}
diff --git a/slirp/slirp.h b/slirp/slirp.h
new file mode 100644
index 000000000..c2fa86e99
--- /dev/null
+++ b/slirp/slirp.h
@@ -0,0 +1,308 @@
+#ifndef __COMMON_H__
+#define __COMMON_H__
+
+#define CONFIG_QEMU
+
+#define DEBUG 1
+
+#ifndef CONFIG_QEMU
+#include "version.h"
+#endif
+#include "config.h"
+#include "slirp_config.h"
+
+#include <sys/types.h>
+#ifdef HAVE_SYS_BITYPES_H
+# include <sys/bitypes.h>
+#endif
+
+#ifdef NEED_TYPEDEFS
+typedef char int8_t;
+typedef unsigned char u_int8_t;
+
+# if SIZEOF_SHORT == 2
+    typedef short int16_t;
+    typedef unsigned short u_int16_t;
+# else
+#  if SIZEOF_INT == 2
+    typedef int int16_t;
+    typedef unsigned int u_int16_t;
+#  else
+    #error Cannot find a type with sizeof() == 2
+#  endif
+# endif
+
+# if SIZEOF_SHORT == 4
+   typedef short int32_t;
+   typedef unsigned short u_int32_t;
+# else
+#  if SIZEOF_INT == 4
+    typedef int int32_t;
+    typedef unsigned int u_int32_t;
+#  else
+    #error Cannot find a type with sizeof() == 4
+#  endif
+# endif
+#endif /* NEED_TYPEDEFS */
+
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#ifdef HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+
+#ifndef HAVE_MEMMOVE
+#define memmove(x, y, z) bcopy(y, x, z)
+#endif
+
+#if TIME_WITH_SYS_TIME
+# include <sys/time.h>
+# include <time.h>
+#else
+# if HAVE_SYS_TIME_H
+#  include <sys/time.h>
+# else
+#  include <time.h>
+# endif
+#endif
+
+#ifdef HAVE_STRING_H
+# include <string.h>
+#else
+# include <strings.h>
+#endif
+
+#include <sys/uio.h>
+
+#ifndef _P
+#ifndef NO_PROTOTYPES
+#  define   _P(x)   x
+#else
+#  define   _P(x)   ()
+#endif
+#endif
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#ifdef GETTIMEOFDAY_ONE_ARG
+#define gettimeofday(x, y) gettimeofday(x)
+#endif
+
+/* Systems lacking strdup() definition in <string.h>. */
+#if defined(ultrix)
+char *strdup _P((const char *));
+#endif
+
+/* Systems lacking malloc() definition in <stdlib.h>. */
+#if defined(ultrix) || defined(hcx)
+void *malloc _P((size_t arg));
+void free _P((void *ptr));
+#endif
+
+#ifndef HAVE_INET_ATON
+int inet_aton _P((const char *cp, struct in_addr *ia));
+#endif
+
+#include <fcntl.h>
+#ifndef NO_UNIX_SOCKETS
+#include <sys/un.h>
+#endif
+#include <signal.h>
+#ifdef HAVE_SYS_SIGNAL_H
+# include <sys/signal.h>
+#endif
+#include <sys/socket.h>
+
+#if defined(WANT_SYS_IOCTL_H) && defined(HAVE_SYS_IOCTL_H)
+# include <sys/ioctl.h>
+#else
+# define WANT_SYS_TERMIOS_H
+#endif
+
+#ifdef WANT_SYS_TERMIOS_H
+# ifndef INCLUDED_TERMIOS_H
+#  ifdef HAVE_TERMIOS_H
+#   include <termios.h>
+#  else
+#   include <termio.h>
+#  endif
+#  define INCLUDED_TERMIOS_H
+# endif
+#endif
+
+
+
+#ifdef HAVE_SYS_SELECT_H
+# include <sys/select.h>
+#endif
+
+#ifdef HAVE_SYS_WAIT_H
+# include <sys/wait.h>
+#endif
+
+#ifdef HAVE_SYS_FILIO_H
+# include <sys/filio.h>
+#endif
+
+#ifdef USE_PPP
+#include <ppp/slirppp.h>
+#endif
+
+#ifdef __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+#include <sys/stat.h>
+
+/* Avoid conflicting with the libc insque() and remque(), which
+   have different prototypes. */
+#define insque slirp_insque
+#define remque slirp_remque
+
+#ifdef HAVE_SYS_STROPTS_H
+#include <sys/stropts.h>
+#endif
+
+#include "debug.h"
+
+#include "ip.h"
+#include "tcp.h"
+#include "tcp_timer.h"
+#include "tcp_var.h"
+#include "tcpip.h"
+#include "udp.h"
+#include "icmp_var.h"
+#include "mbuf.h"
+#include "sbuf.h"
+#include "socket.h"
+#include "if.h"
+#include "main.h"
+#include "misc.h"
+#include "ctl.h"
+#ifdef USE_PPP
+#include "ppp/pppd.h"
+#include "ppp/ppp.h"
+#endif
+
+#include "bootp.h"
+#include "libslirp.h"
+
+extern struct ttys *ttys_unit[MAX_INTERFACES];
+
+#ifndef NULL
+#define NULL (void *)0
+#endif
+
+#ifndef FULL_BOLT
+void if_start _P((void));
+#else
+void if_start _P((struct ttys *));
+#endif
+
+#ifdef BAD_SPRINTF
+# define vsprintf vsprintf_len
+# define sprintf sprintf_len
+ extern int vsprintf_len _P((char *, const char *, va_list));
+ extern int sprintf_len _P((char *, const char *, ...));
+#endif
+
+#ifdef DECLARE_SPRINTF
+# ifndef BAD_SPRINTF
+ extern int vsprintf _P((char *, const char *, va_list));
+# endif
+ extern int vfprintf _P((FILE *, const char *, va_list));
+#endif
+
+#ifndef HAVE_STRERROR
+ extern char *strerror _P((int error));
+#endif
+
+#ifndef HAVE_INDEX
+ char *index _P((const char *, int));
+#endif
+
+#ifndef HAVE_GETHOSTID
+ long gethostid _P((void));
+#endif
+
+void lprint _P((const char *, ...));
+
+extern int do_echo;
+
+#if SIZEOF_CHAR_P == 4
+# define insque_32 insque
+# define remque_32 remque
+#else
+ inline void insque_32 _P((void *, void *));
+ inline void remque_32 _P((void *));
+#endif
+
+#include <pwd.h>
+#include <netdb.h>
+
+#define DEFAULT_BAUD 115200
+
+/* cksum.c */
+int cksum(struct mbuf *m, int len);
+
+/* if.c */
+void if_init _P((void));
+void if_output _P((struct socket *, struct mbuf *));
+
+/* ip_input.c */
+void ip_init _P((void));
+void ip_input _P((struct mbuf *));
+struct ip * ip_reass _P((register struct ipasfrag *, register struct ipq *));
+void ip_freef _P((struct ipq *));
+void ip_enq _P((register struct ipasfrag *, register struct ipasfrag *));
+void ip_deq _P((register struct ipasfrag *));
+void ip_slowtimo _P((void));
+void ip_stripoptions _P((register struct mbuf *, struct mbuf *));
+
+/* ip_output.c */
+int ip_output _P((struct socket *, struct mbuf *));
+
+/* tcp_input.c */
+int tcp_reass _P((register struct tcpcb *, register struct tcpiphdr *, struct mbuf *));
+void tcp_input _P((register struct mbuf *, int, struct socket *));
+void tcp_dooptions _P((struct tcpcb *, u_char *, int, struct tcpiphdr *));
+void tcp_xmit_timer _P((register struct tcpcb *, int));
+int tcp_mss _P((register struct tcpcb *, u_int));
+
+/* tcp_output.c */
+int tcp_output _P((register struct tcpcb *));
+void tcp_setpersist _P((register struct tcpcb *));
+
+/* tcp_subr.c */
+void tcp_init _P((void));
+void tcp_template _P((struct tcpcb *));
+void tcp_respond _P((struct tcpcb *, register struct tcpiphdr *, register struct mbuf *, tcp_seq, tcp_seq, int));
+struct tcpcb * tcp_newtcpcb _P((struct socket *));
+struct tcpcb * tcp_close _P((register struct tcpcb *));
+void tcp_drain _P((void));
+void tcp_sockclosed _P((struct tcpcb *));
+int tcp_fconnect _P((struct socket *));
+void tcp_connect _P((struct socket *));
+int tcp_attach _P((struct socket *));
+u_int8_t tcp_tos _P((struct socket *));
+int tcp_emu _P((struct socket *, struct mbuf *));
+int tcp_ctl _P((struct socket *));
+struct tcpcb *tcp_drop(struct tcpcb *tp, int errno);
+
+#ifdef USE_PPP
+#define MIN_MRU MINMRU
+#define MAX_MRU MAXMRU
+#else
+#define MIN_MRU 128
+#define MAX_MRU 16384
+#endif
+
+#endif
diff --git a/slirp/slirp_config.h b/slirp/slirp_config.h
new file mode 100644
index 000000000..51fc95157
--- /dev/null
+++ b/slirp/slirp_config.h
@@ -0,0 +1,186 @@
+/*
+ * User definable configuration options
+ */
+
+/* Undefine if you don't want talk emulation */
+#undef EMULATE_TALK
+
+/* Define if you want the connection to be probed */
+/* XXX Not working yet, so ignore this for now */
+#undef PROBE_CONN
+
+/* Define to 1 if you want KEEPALIVE timers */
+#define DO_KEEPALIVE 0
+
+/* Define to MAX interfaces you expect to use at once */
+/* MAX_INTERFACES determines the max. TOTAL number of interfaces (SLIP and PPP) */
+/* MAX_PPP_INTERFACES determines max. number of PPP interfaces */
+#define MAX_INTERFACES 1
+#define MAX_PPP_INTERFACES 1
+
+/* Define if you want slirp's socket in /tmp */
+/* XXXXXX Do this in ./configure */
+#undef USE_TMPSOCKET
+
+/* Define if you want slirp to use cfsetXspeed() on the terminal */
+#undef DO_CFSETSPEED
+
+/* Define this if you want slirp to write to the tty as fast as it can */
+/* This should only be set if you are using load-balancing, slirp does a */
+/* pretty good job on single modems already, and seting this will make */
+/* interactive sessions less responsive */
+/* XXXXX Talk about having fast modem as unit 0 */
+#undef FULL_BOLT
+
+/*
+ * Define if you want slirp to use less CPU
+ * You will notice a small lag in interactive sessions, but it's not that bad
+ * Things like Netscape/ftp/etc. are completely unaffected
+ * This is mainly for sysadmins who have many slirp users
+ */
+#undef USE_LOWCPU
+
+/* Define this if your compiler doesn't like prototypes */
+#ifndef __STDC__
+#define NO_PROTOTYPES
+#endif
+
+/*********************************************************/
+/*
+ * Autoconf defined configuration options
+ * You shouldn't need to touch any of these
+ */
+
+/* Ignore this */
+#undef DUMMY_PPP
+
+/* Define if you have unistd.h */
+#define HAVE_UNISTD_H
+
+/* Define if you have stdlib.h */
+#define HAVE_STDLIB_H
+
+/* Define if you have sys/ioctl.h */
+#undef HAVE_SYS_IOCTL_H
+
+/* Define if you have sys/filio.h */
+#undef HAVE_SYS_FILIO_H
+
+/* Define if you have strerror */
+#define HAVE_STRERROR
+
+/* Define if you have strdup() */
+#define HAVE_STRDUP
+
+/* Define according to how time.h should be included */
+#define TIME_WITH_SYS_TIME 0
+#undef HAVE_SYS_TIME_H
+
+/* Define if you have sys/bitypes.h */
+#undef HAVE_SYS_BITYPES_H
+
+/* Define if the machine is big endian */
+//#undef WORDS_BIGENDIAN
+
+/* Define if your sprintf returns char * instead of int */
+#undef BAD_SPRINTF
+
+/* Define if you have readv */
+#undef HAVE_READV
+
+/* Define if iovec needs to be declared */
+#undef DECLARE_IOVEC
+
+/* Define if a declaration of sprintf/fprintf is needed */
+#undef DECLARE_SPRINTF
+
+/* Define if you have a POSIX.1 sys/wait.h */
+#undef HAVE_SYS_WAIT_H
+
+/* Define if you have sys/select.h */
+#define HAVE_SYS_SELECT_H
+
+/* Define if you have strings.h */
+#define HAVE_STRING_H
+
+/* Define if you have arpa/inet.h */
+#define HAVE_ARPA_INET_H
+
+/* Define if you have sys/signal.h */
+#undef HAVE_SYS_SIGNAL_H
+
+/* Define if you have sys/stropts.h */
+#undef HAVE_SYS_STROPTS_H
+
+/* Define to whatever your compiler thinks inline should be */
+#define inline inline
+
+/* Define to whatever your compiler thinks const should be */
+#define const const
+
+/* Define if your compiler doesn't like prototypes */
+#undef NO_PROTOTYPES
+
+/* Define if you don't have u_int32_t etc. typedef'd */
+#undef NEED_TYPEDEFS
+
+/* Define to sizeof(char) */
+#define SIZEOF_CHAR 1
+
+/* Define to sizeof(short) */
+#define SIZEOF_SHORT 2
+
+/* Define to sizeof(int) */
+#define SIZEOF_INT 4
+
+/* Define to sizeof(char *) */
+/* XXX: patch it */
+#define SIZEOF_CHAR_P 4
+
+/* Define if you have random() */
+#undef HAVE_RANDOM
+
+/* Define if you have srandom() */
+#undef HAVE_SRANDOM
+
+/* Define if you have inet_aton */
+#define HAVE_INET_ATON
+
+/* Define if you have setenv */
+#undef HAVE_SETENV
+
+/* Define if you have index() */
+#undef HAVE_INDEX
+
+/* Define if you have bcmp() */
+#undef HAVE_BCMP
+
+/* Define if you have drand48 */
+#undef HAVE_DRAND48
+
+/* Define if you have memmove */
+#define HAVE_MEMMOVE
+
+/* Define if you have <termios.h> */
+#undef HAVE_TERMIOS_H
+
+/* Define if you have gethostid */
+#undef HAVE_GETHOSTID
+
+/* Define if you DON'T have unix-domain sockets */
+#undef NO_UNIX_SOCKETS
+
+/* Define if gettimeofday only takes one argument */
+#undef GETTIMEOFDAY_ONE_ARG
+
+/* Define if you have revoke() */
+#undef HAVE_REVOKE
+
+/* Define if you have the sysv method of opening pty's (/dev/ptmx, etc.) */
+#undef HAVE_GRANTPT
+
+/* Define if you have fchmod */
+#undef HAVE_FCHMOD
+
+/* Define if you have <sys/type32.h> */
+#undef HAVE_SYS_TYPES32_H
diff --git a/slirp/socket.c b/slirp/socket.c
new file mode 100644
index 000000000..396fb4ac7
--- /dev/null
+++ b/slirp/socket.c
@@ -0,0 +1,696 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#define WANT_SYS_IOCTL_H
+#include <slirp.h>
+#include "ip_icmp.h"
+#include "main.h"
+
+void
+so_init()
+{
+	/* Nothing yet */
+}
+
+
+struct socket *
+solookup(head, laddr, lport, faddr, fport)
+	struct socket *head;
+	struct in_addr laddr;
+	u_int lport;
+	struct in_addr faddr;
+	u_int fport;
+{
+	struct socket *so;
+	
+	for (so = head->so_next; so != head; so = so->so_next) {
+		if (so->so_lport == lport && 
+		    so->so_laddr.s_addr == laddr.s_addr &&
+		    so->so_faddr.s_addr == faddr.s_addr &&
+		    so->so_fport == fport)
+		   break;
+	}
+	
+	if (so == head)
+	   return (struct socket *)NULL;
+	return so;
+	
+}
+
+/*
+ * Create a new socket, initialise the fields
+ * It is the responsibility of the caller to
+ * insque() it into the correct linked-list
+ */
+struct socket *
+socreate()
+{
+  struct socket *so;
+	
+  so = (struct socket *)malloc(sizeof(struct socket));
+  if(so) {
+    memset(so, 0, sizeof(struct socket));
+    so->so_state = SS_NOFDREF;
+    so->s = -1;
+  }
+  return(so);
+}
+
+/*
+ * remque and free a socket, clobber cache
+ */
+void
+sofree(so)
+	struct socket *so;
+{
+  if (so->so_emu==EMU_RSH && so->extra) {
+	sofree(so->extra);
+	so->extra=NULL;
+  }
+  if (so == tcp_last_so)
+    tcp_last_so = &tcb;
+  else if (so == udp_last_so)
+    udp_last_so = &udb;
+	
+  m_free(so->so_m);
+	
+  if(so->so_next && so->so_prev) 
+    remque(so);  /* crashes if so is not in a queue */
+
+  free(so);
+}
+
+/*
+ * Read from so's socket into sb_snd, updating all relevant sbuf fields
+ * NOTE: This will only be called if it is select()ed for reading, so
+ * a read() of 0 (or less) means it's disconnected
+ */
+int
+soread(so)
+	struct socket *so;
+{
+	int n, nn, lss, total;
+	struct sbuf *sb = &so->so_snd;
+	int len = sb->sb_datalen - sb->sb_cc;
+	struct iovec iov[2];
+	int mss = so->so_tcpcb->t_maxseg;
+	
+	DEBUG_CALL("soread");
+	DEBUG_ARG("so = %lx", (long )so);
+	
+	/* 
+	 * No need to check if there's enough room to read.
+	 * soread wouldn't have been called if there weren't
+	 */
+	
+	len = sb->sb_datalen - sb->sb_cc;
+	
+	iov[0].iov_base = sb->sb_wptr;
+	if (sb->sb_wptr < sb->sb_rptr) {
+		iov[0].iov_len = sb->sb_rptr - sb->sb_wptr;
+		/* Should never succeed, but... */
+		if (iov[0].iov_len > len)
+		   iov[0].iov_len = len;
+		if (iov[0].iov_len > mss)
+		   iov[0].iov_len -= iov[0].iov_len%mss;
+		n = 1;
+	} else {
+		iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_wptr;
+		/* Should never succeed, but... */
+		if (iov[0].iov_len > len) iov[0].iov_len = len;
+		len -= iov[0].iov_len;
+		if (len) {
+			iov[1].iov_base = sb->sb_data;
+			iov[1].iov_len = sb->sb_rptr - sb->sb_data;
+			if(iov[1].iov_len > len)
+			   iov[1].iov_len = len;
+			total = iov[0].iov_len + iov[1].iov_len;
+			if (total > mss) {
+				lss = total%mss;
+				if (iov[1].iov_len > lss) {
+					iov[1].iov_len -= lss;
+					n = 2;
+				} else {
+					lss -= iov[1].iov_len;
+					iov[0].iov_len -= lss;
+					n = 1;
+				}
+			} else
+				n = 2;
+		} else {
+			if (iov[0].iov_len > mss)
+			   iov[0].iov_len -= iov[0].iov_len%mss;
+			n = 1;
+		}
+	}
+	
+#ifdef HAVE_READV
+	nn = readv(so->s, (struct iovec *)iov, n);
+	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
+#else
+	nn = read(so->s, iov[0].iov_base, iov[0].iov_len);
+#endif	
+	if (nn <= 0) {
+		if (nn < 0 && (errno == EINTR || errno == EAGAIN))
+			return 0;
+		else {
+			DEBUG_MISC((dfd, " --- soread() disconnected, nn = %d, errno = %d-%s\n", nn, errno,strerror(errno)));
+			sofcantrcvmore(so);
+			tcp_sockclosed(sototcpcb(so));
+			return -1;
+		}
+	}
+	
+#ifndef HAVE_READV
+	/*
+	 * If there was no error, try and read the second time round
+	 * We read again if n = 2 (ie, there's another part of the buffer)
+	 * and we read as much as we could in the first read
+	 * We don't test for <= 0 this time, because there legitimately
+	 * might not be any more data (since the socket is non-blocking),
+	 * a close will be detected on next iteration.
+	 * A return of -1 wont (shouldn't) happen, since it didn't happen above
+	 */
+	if (n == 2 && nn == iov[0].iov_len)
+	   nn += read(so->s, iov[1].iov_base, iov[1].iov_len);
+	
+	DEBUG_MISC((dfd, " ... read nn = %d bytes\n", nn));
+#endif
+	
+	/* Update fields */
+	sb->sb_cc += nn;
+	sb->sb_wptr += nn;
+	if (sb->sb_wptr >= (sb->sb_data + sb->sb_datalen))
+		sb->sb_wptr -= sb->sb_datalen;
+	return nn;
+}
+	
+/*
+ * Get urgent data
+ * 
+ * When the socket is created, we set it SO_OOBINLINE,
+ * so when OOB data arrives, we soread() it and everything
+ * in the send buffer is sent as urgent data
+ */
+void
+sorecvoob(so)
+	struct socket *so;
+{
+	struct tcpcb *tp = sototcpcb(so);
+
+	DEBUG_CALL("sorecvoob");
+	DEBUG_ARG("so = %lx", (long)so);
+	
+	/*
+	 * We take a guess at how much urgent data has arrived.
+	 * In most situations, when urgent data arrives, the next
+	 * read() should get all the urgent data.  This guess will
+	 * be wrong however if more data arrives just after the
+	 * urgent data, or the read() doesn't return all the 
+	 * urgent data.
+	 */
+	soread(so);
+	tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
+	tp->t_force = 1;
+	tcp_output(tp);
+	tp->t_force = 0;
+}
+
+/*
+ * Send urgent data
+ * There's a lot duplicated code here, but...
+ */
+int
+sosendoob(so)
+	struct socket *so;
+{
+	struct sbuf *sb = &so->so_rcv;
+	char buff[2048]; /* XXX Shouldn't be sending more oob data than this */
+	
+	int n, len;
+	
+	DEBUG_CALL("sosendoob");
+	DEBUG_ARG("so = %lx", (long)so);
+	DEBUG_ARG("sb->sb_cc = %d", sb->sb_cc);
+	
+	if (so->so_urgc > 2048)
+	   so->so_urgc = 2048; /* XXXX */
+	
+	if (sb->sb_rptr < sb->sb_wptr) {
+		/* We can send it directly */
+		n = send(so->s, sb->sb_rptr, so->so_urgc, (MSG_OOB)); /* |MSG_DONTWAIT)); */
+		so->so_urgc -= n;
+		
+		DEBUG_MISC((dfd, " --- sent %d bytes urgent data, %d urgent bytes left\n", n, so->so_urgc));
+	} else {
+		/* 
+		 * Since there's no sendv or sendtov like writev,
+		 * we must copy all data to a linear buffer then
+		 * send it all
+		 */
+		len = (sb->sb_data + sb->sb_datalen) - sb->sb_rptr;
+		if (len > so->so_urgc) len = so->so_urgc;
+		memcpy(buff, sb->sb_rptr, len);
+		so->so_urgc -= len;
+		if (so->so_urgc) {
+			n = sb->sb_wptr - sb->sb_data;
+			if (n > so->so_urgc) n = so->so_urgc;
+			memcpy((buff + len), sb->sb_data, n);
+			so->so_urgc -= n;
+			len += n;
+		}
+		n = send(so->s, buff, len, (MSG_OOB)); /* |MSG_DONTWAIT)); */
+#ifdef DEBUG
+		if (n != len)
+		   DEBUG_ERROR((dfd, "Didn't send all data urgently XXXXX\n"));
+#endif		
+		DEBUG_MISC((dfd, " ---2 sent %d bytes urgent data, %d urgent bytes left\n", n, so->so_urgc));
+	}
+	
+	sb->sb_cc -= n;
+	sb->sb_rptr += n;
+	if (sb->sb_rptr >= (sb->sb_data + sb->sb_datalen))
+		sb->sb_rptr -= sb->sb_datalen;
+	
+	return n;
+}
+
+/*
+ * Write data from so_rcv to so's socket, 
+ * updating all sbuf field as necessary
+ */
+int
+sowrite(so)
+	struct socket *so;
+{
+	int  n,nn;
+	struct sbuf *sb = &so->so_rcv;
+	int len = sb->sb_cc;
+	struct iovec iov[2];
+	
+	DEBUG_CALL("sowrite");
+	DEBUG_ARG("so = %lx", (long)so);
+	
+	if (so->so_urgc) {
+		sosendoob(so);
+		if (sb->sb_cc == 0)
+			return 0;
+	}
+
+	/*
+	 * No need to check if there's something to write,
+	 * sowrite wouldn't have been called otherwise
+	 */
+	
+        len = sb->sb_cc;
+	
+	iov[0].iov_base = sb->sb_rptr;
+	if (sb->sb_rptr < sb->sb_wptr) {
+		iov[0].iov_len = sb->sb_wptr - sb->sb_rptr;
+		/* Should never succeed, but... */
+		if (iov[0].iov_len > len) iov[0].iov_len = len;
+		n = 1;
+	} else {
+		iov[0].iov_len = (sb->sb_data + sb->sb_datalen) - sb->sb_rptr;
+		if (iov[0].iov_len > len) iov[0].iov_len = len;
+		len -= iov[0].iov_len;
+		if (len) {
+			iov[1].iov_base = sb->sb_data;
+			iov[1].iov_len = sb->sb_wptr - sb->sb_data;
+			if (iov[1].iov_len > len) iov[1].iov_len = len;
+			n = 2;
+		} else
+			n = 1;
+	}
+	/* Check if there's urgent data to send, and if so, send it */
+
+#ifdef HAVE_READV
+	nn = writev(so->s, (const struct iovec *)iov, n);
+	
+	DEBUG_MISC((dfd, "  ... wrote nn = %d bytes\n", nn));
+#else
+	nn = write(so->s, iov[0].iov_base, iov[0].iov_len);
+#endif
+	/* This should never happen, but people tell me it does *shrug* */
+	if (nn < 0 && (errno == EAGAIN || errno == EINTR))
+		return 0;
+	
+	if (nn <= 0) {
+		DEBUG_MISC((dfd, " --- sowrite disconnected, so->so_state = %x, errno = %d\n",
+			so->so_state, errno));
+		sofcantsendmore(so);
+		tcp_sockclosed(sototcpcb(so));
+		return -1;
+	}
+	
+#ifndef HAVE_READV
+	if (n == 2 && nn == iov[0].iov_len)
+	   nn += write(so->s, iov[1].iov_base, iov[1].iov_len);
+        DEBUG_MISC((dfd, "  ... wrote nn = %d bytes\n", nn));
+#endif
+	
+	/* Update sbuf */
+	sb->sb_cc -= nn;
+	sb->sb_rptr += nn;
+	if (sb->sb_rptr >= (sb->sb_data + sb->sb_datalen))
+		sb->sb_rptr -= sb->sb_datalen;
+	
+	/*
+	 * If in DRAIN mode, and there's no more data, set
+	 * it CANTSENDMORE
+	 */
+	if ((so->so_state & SS_FWDRAIN) && sb->sb_cc == 0)
+		sofcantsendmore(so);
+	
+	return nn;
+}
+
+/*
+ * recvfrom() a UDP socket
+ */
+void
+sorecvfrom(so)
+	struct socket *so;
+{
+	struct sockaddr_in addr;
+	int addrlen = sizeof(struct sockaddr_in);
+	
+	DEBUG_CALL("sorecvfrom");
+	DEBUG_ARG("so = %lx", (long)so);
+	
+	if (so->so_type == IPPROTO_ICMP) {   /* This is a "ping" reply */
+	  char buff[256];
+	  int len;
+		
+	  len = recvfrom(so->s, buff, 256, 0, 
+			 (struct sockaddr *)&addr, &addrlen);
+	  /* XXX Check if reply is "correct"? */
+	  
+	  if(len == -1 || len == 0) {
+	    u_char code=ICMP_UNREACH_PORT;
+
+	    if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
+	    else if(errno == ENETUNREACH) code=ICMP_UNREACH_NET;
+	    
+	    DEBUG_MISC((dfd," udp icmp rx errno = %d-%s\n",
+			errno,strerror(errno)));
+	    icmp_error(so->so_m, ICMP_UNREACH,code, 0,strerror(errno));
+	  } else {
+	    icmp_reflect(so->so_m);
+	    so->so_m = 0; /* Don't m_free() it again! */
+	  }
+	  /* No need for this socket anymore, udp_detach it */
+	  udp_detach(so);
+	} else {                            	/* A "normal" UDP packet */
+	  struct mbuf *m;
+	  int len, n;
+
+	  if (!(m = m_get())) return;
+	  m->m_data += if_maxlinkhdr;
+		
+	  /* 
+	   * XXX Shouldn't FIONREAD packets destined for port 53,
+	   * but I don't know the max packet size for DNS lookups
+	   */
+	  len = M_FREEROOM(m);
+	  /* if (so->so_fport != htons(53)) { */
+	  ioctl(so->s, FIONREAD, &n);
+	  
+	  if (n > len) {
+	    n = (m->m_data - m->m_dat) + m->m_len + n + 1;
+	    m_inc(m, n);
+	    len = M_FREEROOM(m);
+	  }
+	  /* } */
+		
+	  m->m_len = recvfrom(so->s, m->m_data, len, 0,
+			      (struct sockaddr *)&addr, &addrlen);
+	  DEBUG_MISC((dfd, " did recvfrom %d, errno = %d-%s\n", 
+		      m->m_len, errno,strerror(errno)));
+	  if(m->m_len<0) {
+	    u_char code=ICMP_UNREACH_PORT;
+
+	    if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
+	    else if(errno == ENETUNREACH) code=ICMP_UNREACH_NET;
+	    
+	    DEBUG_MISC((dfd," rx error, tx icmp ICMP_UNREACH:%i\n", code));
+	    icmp_error(so->so_m, ICMP_UNREACH,code, 0,strerror(errno));
+	    m_free(m);
+	  } else {
+	  /*
+	   * Hack: domain name lookup will be used the most for UDP,
+	   * and since they'll only be used once there's no need
+	   * for the 4 minute (or whatever) timeout... So we time them
+	   * out much quicker (10 seconds  for now...)
+	   */
+	    if (so->so_expire) {
+	      if (so->so_fport == htons(53))
+		so->so_expire = curtime + SO_EXPIREFAST;
+	      else
+		so->so_expire = curtime + SO_EXPIRE;
+	    }
+
+	    /*		if (m->m_len == len) {
+	     *			m_inc(m, MINCSIZE);
+	     *			m->m_len = 0;
+	     *		}
+	     */
+	    
+	    /* 
+	     * If this packet was destined for CTL_ADDR,
+	     * make it look like that's where it came from, done by udp_output
+	     */
+	    udp_output(so, m, &addr);
+	  } /* rx error */
+	} /* if ping packet */
+}
+
+/*
+ * sendto() a socket
+ */
+int
+sosendto(so, m)
+	struct socket *so;
+	struct mbuf *m;
+{
+	int ret;
+	struct sockaddr_in addr;
+
+	DEBUG_CALL("sosendto");
+	DEBUG_ARG("so = %lx", (long)so);
+	DEBUG_ARG("m = %lx", (long)m);
+	
+        addr.sin_family = AF_INET;
+	if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) {
+	  /* It's an alias */
+	  switch(ntohl(so->so_faddr.s_addr) & 0xff) {
+	  case CTL_DNS:
+	    addr.sin_addr = dns_addr;
+	    break;
+	  case CTL_ALIAS:
+	  default:
+	    addr.sin_addr = loopback_addr;
+	    break;
+	  }
+	} else
+	  addr.sin_addr = so->so_faddr;
+	addr.sin_port = so->so_fport;
+
+	DEBUG_MISC((dfd, " sendto()ing, addr.sin_port=%d, addr.sin_addr.s_addr=%.16s\n", ntohs(addr.sin_port), inet_ntoa(addr.sin_addr)));
+	
+	/* Don't care what port we get */
+	ret = sendto(so->s, m->m_data, m->m_len, 0,
+		     (struct sockaddr *)&addr, sizeof (struct sockaddr));
+	if (ret < 0)
+		return -1;
+	
+	/*
+	 * Kill the socket if there's no reply in 4 minutes,
+	 * but only if it's an expirable socket
+	 */
+	if (so->so_expire)
+		so->so_expire = curtime + SO_EXPIRE;
+	so->so_state = SS_ISFCONNECTED; /* So that it gets select()ed */
+	return 0;
+}
+
+/*
+ * XXX This should really be tcp_listen
+ */
+struct socket *
+solisten(port, laddr, lport, flags)
+	u_int port;
+	u_int32_t laddr;
+	u_int lport;
+	int flags;
+{
+	struct sockaddr_in addr;
+	struct socket *so;
+	int s, addrlen = sizeof(addr), opt = 1;
+
+	DEBUG_CALL("solisten");
+	DEBUG_ARG("port = %d", port);
+	DEBUG_ARG("laddr = %x", laddr);
+	DEBUG_ARG("lport = %d", lport);
+	DEBUG_ARG("flags = %x", flags);
+	
+	if ((so = socreate()) == NULL) {
+	  /* free(so);      Not sofree() ??? free(NULL) == NOP */
+	  return NULL;
+	}
+	
+	/* Don't tcp_attach... we don't need so_snd nor so_rcv */
+	if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL) {
+		free(so);
+		return NULL;
+	}
+	insque(so,&tcb);
+	
+	/* 
+	 * SS_FACCEPTONCE sockets must time out.
+	 */
+	if (flags & SS_FACCEPTONCE)
+	   so->so_tcpcb->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT*2;
+	
+	so->so_state = (SS_FACCEPTCONN|flags);
+	so->so_lport = lport; /* Kept in network format */
+	so->so_laddr.s_addr = laddr; /* Ditto */
+	
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = INADDR_ANY;
+	addr.sin_port = port;
+	
+	if (((s = socket(AF_INET,SOCK_STREAM,0)) < 0) ||
+	    (bind(s,(struct sockaddr *)&addr, sizeof(addr)) < 0) ||
+	    (listen(s,1) < 0)) {
+		int tmperrno = errno; /* Don't clobber the real reason we failed */
+		
+		close(s);
+		sofree(so);
+		/* Restore the real errno */
+		errno = tmperrno;
+		return NULL;
+	}
+	setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
+	setsockopt(s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int));
+	
+	getsockname(s,(struct sockaddr *)&addr,&addrlen);
+	so->so_fport = addr.sin_port;
+	if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr)
+	   so->so_faddr = our_addr;
+	else
+	   so->so_faddr = addr.sin_addr;
+
+	so->s = s;
+	return so;
+}
+
+/* 
+ * Data is available in so_rcv
+ * Just write() the data to the socket
+ * XXX not yet...
+ */
+void
+sorwakeup(so)
+	struct socket *so;
+{
+/*	sowrite(so); */
+/*	FD_CLR(so->s,&writefds); */
+}
+	
+/*
+ * Data has been freed in so_snd
+ * We have room for a read() if we want to
+ * For now, don't read, it'll be done in the main loop
+ */
+void
+sowwakeup(so)
+	struct socket *so;
+{
+	/* Nothing, yet */
+}
+
+/*
+ * Various session state calls
+ * XXX Should be #define's
+ * The socket state stuff needs work, these often get call 2 or 3
+ * times each when only 1 was needed
+ */
+void
+soisfconnecting(so)
+	register struct socket *so;
+{
+	so->so_state &= ~(SS_NOFDREF|SS_ISFCONNECTED|SS_FCANTRCVMORE|
+			  SS_FCANTSENDMORE|SS_FWDRAIN);
+	so->so_state |= SS_ISFCONNECTING; /* Clobber other states */
+}
+
+void
+soisfconnected(so)
+        register struct socket *so;
+{
+	so->so_state &= ~(SS_ISFCONNECTING|SS_FWDRAIN|SS_NOFDREF);
+	so->so_state |= SS_ISFCONNECTED; /* Clobber other states */
+}
+
+void
+sofcantrcvmore(so)
+	struct  socket *so;
+{
+	if ((so->so_state & SS_NOFDREF) == 0) {
+		shutdown(so->s,0);
+		FD_CLR(so->s, global_writefds);
+	}
+	so->so_state &= ~(SS_ISFCONNECTING);
+	if (so->so_state & SS_FCANTSENDMORE)
+	   so->so_state = SS_NOFDREF; /* Don't select it */ /* XXX close() here as well? */
+	else
+	   so->so_state |= SS_FCANTRCVMORE;
+}
+
+void
+sofcantsendmore(so)
+	struct socket *so;
+{
+	if ((so->so_state & SS_NOFDREF) == 0) {
+		shutdown(so->s,1);           /* send FIN to fhost */
+		FD_CLR(so->s, global_readfds);
+		FD_CLR(so->s, global_xfds);
+	}
+	so->so_state &= ~(SS_ISFCONNECTING);
+	if (so->so_state & SS_FCANTRCVMORE)
+	   so->so_state = SS_NOFDREF; /* as above */
+	else
+	   so->so_state |= SS_FCANTSENDMORE;
+}
+
+void
+soisfdisconnected(so)
+	struct socket *so;
+{
+/*	so->so_state &= ~(SS_ISFCONNECTING|SS_ISFCONNECTED); */
+/*	close(so->s); */
+/*	so->so_state = SS_ISFDISCONNECTED; */
+	/*
+	 * XXX Do nothing ... ?
+	 */
+}
+
+/*
+ * Set write drain mode
+ * Set CANTSENDMORE once all data has been write()n
+ */
+void
+sofwdrain(so)
+	struct socket *so;
+{
+	if (so->so_rcv.sb_cc)
+		so->so_state |= SS_FWDRAIN;
+	else
+		sofcantsendmore(so);
+}
+
diff --git a/slirp/socket.h b/slirp/socket.h
new file mode 100644
index 000000000..d05354c8c
--- /dev/null
+++ b/slirp/socket.h
@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+/* MINE */
+
+#ifndef _SLIRP_SOCKET_H_
+#define _SLIRP_SOCKET_H_
+
+#define SO_EXPIRE 240000
+#define SO_EXPIREFAST 10000
+
+/*
+ * Our socket structure
+ */
+
+struct socket {
+  struct socket *so_next,*so_prev;      /* For a linked list of sockets */
+
+  int s;                           /* The actual socket */
+
+			/* XXX union these with not-yet-used sbuf params */
+  struct mbuf *so_m;	           /* Pointer to the original SYN packet,
+				    * for non-blocking connect()'s, and
+				    * PING reply's */
+  struct tcpiphdr *so_ti;	   /* Pointer to the original ti within
+				    * so_mconn, for non-blocking connections */
+  int so_urgc;
+  struct in_addr so_faddr;	   /* foreign host table entry */
+  struct in_addr so_laddr;	   /* local host table entry */
+  u_int16_t so_fport;		   /* foreign port */
+  u_int16_t so_lport;		   /* local port */
+  
+  u_int8_t	so_iptos;	/* Type of service */
+  u_int8_t	so_emu;		/* Is the socket emulated? */
+  
+  u_char	so_type;		/* Type of socket, UDP or TCP */
+  int	so_state;		/* internal state flags SS_*, below */
+  
+  struct 	tcpcb *so_tcpcb;	/* pointer to TCP protocol control block */
+  u_int	so_expire;		/* When the socket will expire */
+  
+  int	so_queued;		/* Number of packets queued from this socket */
+  int	so_nqueued;		/* Number of packets queued in a row
+				 * Used to determine when to "downgrade" a session
+					 * from fastq to batchq */
+	
+  struct sbuf so_rcv;		/* Receive buffer */
+  struct sbuf so_snd;		/* Send buffer */
+  void * extra;			/* Extra pointer */
+};
+
+
+/*
+ * Socket state bits. (peer means the host on the Internet,
+ * local host means the host on the other end of the modem)
+ */
+#define SS_NOFDREF		0x001	/* No fd reference */
+
+#define SS_ISFCONNECTING	0x002	/* Socket is connecting to peer (non-blocking connect()'s) */
+#define SS_ISFCONNECTED		0x004	/* Socket is connected to peer */
+#define SS_FCANTRCVMORE		0x008	/* Socket can't receive more from peer (for half-closes) */
+#define SS_FCANTSENDMORE	0x010	/* Socket can't send more to peer (for half-closes) */
+/* #define SS_ISFDISCONNECTED	0x020*/	/* Socket has disconnected from peer, in 2MSL state */
+#define SS_FWDRAIN		0x040	/* We received a FIN, drain data and set SS_FCANTSENDMORE */
+
+#define SS_CTL			0x080
+#define SS_FACCEPTCONN		0x100	/* Socket is accepting connections from a host on the internet */
+#define SS_FACCEPTONCE		0x200	/* If set, the SS_FACCEPTCONN socket will die after one accept */
+
+extern struct socket tcb;
+
+
+#if defined(DECLARE_IOVEC) && !defined(HAVE_READV)
+struct iovec {
+	char *iov_base;
+	size_t iov_len;
+};
+#endif
+
+void so_init _P((void));
+struct socket * solookup _P((struct socket *, struct in_addr, u_int, struct in_addr, u_int));
+struct socket * socreate _P((void));
+void sofree _P((struct socket *));
+int soread _P((struct socket *));
+void sorecvoob _P((struct socket *));
+int sosendoob _P((struct socket *));
+int sowrite _P((struct socket *));
+void sorecvfrom _P((struct socket *));
+int sosendto _P((struct socket *, struct mbuf *));
+struct socket * solisten _P((u_int, u_int32_t, u_int, int));
+void sorwakeup _P((struct socket *));
+void sowwakeup _P((struct socket *));
+void soisfconnecting _P((register struct socket *));
+void soisfconnected _P((register struct socket *));
+void sofcantrcvmore _P((struct  socket *));
+void sofcantsendmore _P((struct socket *));
+void soisfdisconnected _P((struct socket *));
+void sofwdrain _P((struct socket *));
+
+#endif /* _SOCKET_H_ */
diff --git a/slirp/tcp.h b/slirp/tcp.h
new file mode 100644
index 000000000..3e0b4dd8f
--- /dev/null
+++ b/slirp/tcp.h
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp.h	8.1 (Berkeley) 6/10/93
+ * tcp.h,v 1.3 1994/08/21 05:27:34 paul Exp
+ */
+
+#ifndef _TCP_H_
+#define _TCP_H_
+
+typedef	u_int32_t	tcp_seq;
+
+#define      PR_SLOWHZ       2               /* 2 slow timeouts per second (approx) */
+#define      PR_FASTHZ       5               /* 5 fast timeouts per second (not important) */
+
+extern int tcp_rcvspace;
+extern int tcp_sndspace;
+extern struct socket *tcp_last_so;
+
+#define TCP_SNDSPACE 8192
+#define TCP_RCVSPACE 8192
+
+/*
+ * TCP header.
+ * Per RFC 793, September, 1981.
+ */
+struct tcphdr {
+	u_int16_t	th_sport;		/* source port */
+	u_int16_t	th_dport;		/* destination port */
+	tcp_seq	th_seq;			/* sequence number */
+	tcp_seq	th_ack;			/* acknowledgement number */
+#ifdef WORDS_BIGENDIAN
+	u_int	th_off:4,		/* data offset */
+		th_x2:4;		/* (unused) */
+#else
+	u_int	th_x2:4,		/* (unused) */
+		th_off:4;		/* data offset */
+#endif
+	u_int8_t	th_flags;
+#define	TH_FIN	0x01
+#define	TH_SYN	0x02
+#define	TH_RST	0x04
+#define	TH_PUSH	0x08
+#define	TH_ACK	0x10
+#define	TH_URG	0x20
+	u_int16_t	th_win;			/* window */
+	u_int16_t	th_sum;			/* checksum */
+	u_int16_t	th_urp;			/* urgent pointer */
+};
+
+#include "tcp_var.h"
+
+#define	TCPOPT_EOL		0
+#define	TCPOPT_NOP		1
+#define	TCPOPT_MAXSEG		2
+#define    TCPOLEN_MAXSEG		4
+#define TCPOPT_WINDOW		3
+#define    TCPOLEN_WINDOW		3
+#define TCPOPT_SACK_PERMITTED	4		/* Experimental */
+#define    TCPOLEN_SACK_PERMITTED	2
+#define TCPOPT_SACK		5		/* Experimental */
+#define TCPOPT_TIMESTAMP	8
+#define    TCPOLEN_TIMESTAMP		10
+#define    TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
+
+#define TCPOPT_TSTAMP_HDR	\
+    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
+
+/*
+ * Default maximum segment size for TCP.
+ * With an IP MSS of 576, this is 536,
+ * but 512 is probably more convenient.
+ * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
+ */
+#define	TCP_MSS	512
+
+#define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
+
+#define TCP_MAX_WINSHIFT	14	/* maximum window shift */
+
+/*
+ * User-settable options (used with setsockopt).
+ */
+/* #define	TCP_NODELAY	0x01 */	/* don't delay send to coalesce packets */
+/* #define	TCP_MAXSEG	0x02 */	/* set maximum segment size */
+
+/*
+ * TCP FSM state definitions.
+ * Per RFC793, September, 1981.
+ */
+
+#define TCP_NSTATES     11
+
+#define TCPS_CLOSED             0       /* closed */
+#define TCPS_LISTEN             1       /* listening for connection */
+#define TCPS_SYN_SENT           2       /* active, have sent syn */
+#define TCPS_SYN_RECEIVED       3       /* have send and received syn */
+/* states < TCPS_ESTABLISHED are those where connections not established */
+#define TCPS_ESTABLISHED        4       /* established */
+#define TCPS_CLOSE_WAIT         5       /* rcvd fin, waiting for close */
+/* states > TCPS_CLOSE_WAIT are those where user has closed */
+#define TCPS_FIN_WAIT_1         6       /* have closed, sent fin */
+#define TCPS_CLOSING            7       /* closed xchd FIN; await FIN ACK */
+#define TCPS_LAST_ACK           8       /* had fin and close; await FIN ACK */
+/* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
+#define TCPS_FIN_WAIT_2         9       /* have closed, fin is acked */
+#define TCPS_TIME_WAIT          10      /* in 2*msl quiet wait after close */
+
+#define TCPS_HAVERCVDSYN(s)     ((s) >= TCPS_SYN_RECEIVED)
+#define TCPS_HAVEESTABLISHED(s) ((s) >= TCPS_ESTABLISHED)
+#define TCPS_HAVERCVDFIN(s)     ((s) >= TCPS_TIME_WAIT)
+
+/*
+ * TCP sequence numbers are 32 bit integers operated
+ * on with modular arithmetic.  These macros can be
+ * used to compare such integers.
+ */
+#define SEQ_LT(a,b)     ((int)((a)-(b)) < 0)
+#define SEQ_LEQ(a,b)    ((int)((a)-(b)) <= 0)
+#define SEQ_GT(a,b)     ((int)((a)-(b)) > 0)
+#define SEQ_GEQ(a,b)    ((int)((a)-(b)) >= 0)
+
+/*
+ * Macros to initialize tcp sequence numbers for
+ * send and receive from initial send and receive
+ * sequence numbers.
+ */
+#define tcp_rcvseqinit(tp) \
+     (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
+
+#define tcp_sendseqinit(tp) \
+    (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = (tp)->iss
+
+#define TCP_ISSINCR     (125*1024)      /* increment for tcp_iss each second */
+
+extern tcp_seq tcp_iss;                /* tcp initial send seq # */
+
+extern char *tcpstates[];
+
+#endif
diff --git a/slirp/tcp_input.c b/slirp/tcp_input.c
new file mode 100644
index 000000000..eeee98597
--- /dev/null
+++ b/slirp/tcp_input.c
@@ -0,0 +1,1745 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_input.c	8.5 (Berkeley) 4/10/94
+ * tcp_input.c,v 1.10 1994/10/13 18:36:32 wollman Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include "ip_icmp.h"
+
+struct socket tcb;
+
+#define min(x,y) ((x) < (y) ? (x) : (y))
+#define max(x,y) ((x) > (y) ? (x) : (y))
+
+int	tcprexmtthresh = 3;
+struct	socket *tcp_last_so = &tcb;
+
+tcp_seq tcp_iss;                /* tcp initial send seq # */
+
+#define TCP_PAWS_IDLE	(24 * 24 * 60 * 60 * PR_SLOWHZ)
+
+/* for modulo comparisons of timestamps */
+#define TSTMP_LT(a,b)	((int)((a)-(b)) < 0)
+#define TSTMP_GEQ(a,b)	((int)((a)-(b)) >= 0)
+
+/*
+ * Insert segment ti into reassembly queue of tcp with
+ * control block tp.  Return TH_FIN if reassembly now includes
+ * a segment with FIN.  The macro form does the common case inline
+ * (segment is the next to be received on an established connection,
+ * and the queue is empty), avoiding linkage into and removal
+ * from the queue and repetition of various conversions.
+ * Set DELACK for segments received in order, but ack immediately
+ * when segments are out of order (so fast retransmit can work).
+ */
+#ifdef TCP_ACK_HACK
+#define TCP_REASS(tp, ti, m, so, flags) {\
+       if ((ti)->ti_seq == (tp)->rcv_nxt && \
+           (tp)->seg_next == (tcpiphdrp_32)(tp) && \
+           (tp)->t_state == TCPS_ESTABLISHED) {\
+               if (ti->ti_flags & TH_PUSH) \
+                       tp->t_flags |= TF_ACKNOW; \
+               else \
+                       tp->t_flags |= TF_DELACK; \
+               (tp)->rcv_nxt += (ti)->ti_len; \
+               flags = (ti)->ti_flags & TH_FIN; \
+               tcpstat.tcps_rcvpack++;\
+               tcpstat.tcps_rcvbyte += (ti)->ti_len;\
+               if (so->so_emu) { \
+		       if (tcp_emu((so),(m))) sbappend((so), (m)); \
+	       } else \
+	       	       sbappend((so), (m)); \
+/*               sorwakeup(so); */ \
+	} else {\
+               (flags) = tcp_reass((tp), (ti), (m)); \
+               tp->t_flags |= TF_ACKNOW; \
+       } \
+}
+#else
+#define	TCP_REASS(tp, ti, m, so, flags) { \
+	if ((ti)->ti_seq == (tp)->rcv_nxt && \
+	    (tp)->seg_next == (tcpiphdrp_32)(tp) && \
+	    (tp)->t_state == TCPS_ESTABLISHED) { \
+		tp->t_flags |= TF_DELACK; \
+		(tp)->rcv_nxt += (ti)->ti_len; \
+		flags = (ti)->ti_flags & TH_FIN; \
+		tcpstat.tcps_rcvpack++;\
+		tcpstat.tcps_rcvbyte += (ti)->ti_len;\
+		if (so->so_emu) { \
+			if (tcp_emu((so),(m))) sbappend(so, (m)); \
+		} else \
+			sbappend((so), (m)); \
+/*		sorwakeup(so); */ \
+	} else { \
+		(flags) = tcp_reass((tp), (ti), (m)); \
+		tp->t_flags |= TF_ACKNOW; \
+	} \
+}
+#endif
+
+int
+tcp_reass(tp, ti, m)
+	register struct tcpcb *tp;
+	register struct tcpiphdr *ti;
+	struct mbuf *m;
+{
+	register struct tcpiphdr *q;
+	struct socket *so = tp->t_socket;
+	int flags;
+	
+	/*
+	 * Call with ti==0 after become established to
+	 * force pre-ESTABLISHED data up to user socket.
+	 */
+	if (ti == 0)
+		goto present;
+
+	/*
+	 * Find a segment which begins after this one does.
+	 */
+	for (q = (struct tcpiphdr *)tp->seg_next; q != (struct tcpiphdr *)tp;
+	    q = (struct tcpiphdr *)q->ti_next)
+		if (SEQ_GT(q->ti_seq, ti->ti_seq))
+			break;
+
+	/*
+	 * If there is a preceding segment, it may provide some of
+	 * our data already.  If so, drop the data from the incoming
+	 * segment.  If it provides all of our data, drop us.
+	 */
+	if ((struct tcpiphdr *)q->ti_prev != (struct tcpiphdr *)tp) {
+		register int i;
+		q = (struct tcpiphdr *)q->ti_prev;
+		/* conversion to int (in i) handles seq wraparound */
+		i = q->ti_seq + q->ti_len - ti->ti_seq;
+		if (i > 0) {
+			if (i >= ti->ti_len) {
+				tcpstat.tcps_rcvduppack++;
+				tcpstat.tcps_rcvdupbyte += ti->ti_len;
+				m_freem(m);
+				/*
+				 * Try to present any queued data
+				 * at the left window edge to the user.
+				 * This is needed after the 3-WHS
+				 * completes.
+				 */
+				goto present;   /* ??? */
+			}
+			m_adj(m, i);
+			ti->ti_len -= i;
+			ti->ti_seq += i;
+		}
+		q = (struct tcpiphdr *)(q->ti_next);
+	}
+	tcpstat.tcps_rcvoopack++;
+	tcpstat.tcps_rcvoobyte += ti->ti_len;
+	REASS_MBUF(ti) = (mbufp_32) m;		/* XXX */
+
+	/*
+	 * While we overlap succeeding segments trim them or,
+	 * if they are completely covered, dequeue them.
+	 */
+	while (q != (struct tcpiphdr *)tp) {
+		register int i = (ti->ti_seq + ti->ti_len) - q->ti_seq;
+		if (i <= 0)
+			break;
+		if (i < q->ti_len) {
+			q->ti_seq += i;
+			q->ti_len -= i;
+			m_adj((struct mbuf *) REASS_MBUF(q), i);
+			break;
+		}
+		q = (struct tcpiphdr *)q->ti_next;
+		m = (struct mbuf *) REASS_MBUF((struct tcpiphdr *)q->ti_prev);
+		remque_32((void *)(q->ti_prev));
+		m_freem(m);
+	}
+
+	/*
+	 * Stick new segment in its place.
+	 */
+	insque_32(ti, (void *)(q->ti_prev));
+
+present:
+	/*
+	 * Present data to user, advancing rcv_nxt through
+	 * completed sequence space.
+	 */
+	if (!TCPS_HAVEESTABLISHED(tp->t_state))
+		return (0);
+	ti = (struct tcpiphdr *) tp->seg_next;
+	if (ti == (struct tcpiphdr *)tp || ti->ti_seq != tp->rcv_nxt)
+		return (0);
+	if (tp->t_state == TCPS_SYN_RECEIVED && ti->ti_len)
+		return (0);
+	do {
+		tp->rcv_nxt += ti->ti_len;
+		flags = ti->ti_flags & TH_FIN;
+		remque_32(ti);
+		m = (struct mbuf *) REASS_MBUF(ti); /* XXX */
+		ti = (struct tcpiphdr *)ti->ti_next;
+/*		if (so->so_state & SS_FCANTRCVMORE) */
+		if (so->so_state & SS_FCANTSENDMORE)
+			m_freem(m);
+		else {
+			if (so->so_emu) {
+				if (tcp_emu(so,m)) sbappend(so, m);
+			} else
+				sbappend(so, m);
+		}
+	} while (ti != (struct tcpiphdr *)tp && ti->ti_seq == tp->rcv_nxt);
+/*	sorwakeup(so); */
+	return (flags);
+}
+
+/*
+ * TCP input routine, follows pages 65-76 of the
+ * protocol specification dated September, 1981 very closely.
+ */
+void
+tcp_input(m, iphlen, inso)
+	register struct mbuf *m;
+	int iphlen;
+	struct socket *inso;
+{
+  	struct ip save_ip, *ip;
+	register struct tcpiphdr *ti;
+	caddr_t optp = NULL;
+	int optlen = 0;
+	int len, tlen, off;
+	register struct tcpcb *tp = 0;
+	register int tiflags;
+	struct socket *so = 0;
+	int todrop, acked, ourfinisacked, needoutput = 0;
+/*	int dropsocket = 0; */
+	int iss = 0;
+	u_long tiwin;
+	int ret;
+/*	int ts_present = 0; */
+
+	DEBUG_CALL("tcp_input");
+	DEBUG_ARGS((dfd," m = %8lx  iphlen = %2d  inso = %lx\n", 
+		    (long )m, iphlen, (long )inso ));
+	
+	/*
+	 * If called with m == 0, then we're continuing the connect
+	 */
+	if (m == NULL) {
+		so = inso;
+		
+		/* Re-set a few variables */
+		tp = sototcpcb(so);
+		m = so->so_m;
+		so->so_m = 0;
+		ti = so->so_ti;
+		tiwin = ti->ti_win;
+		tiflags = ti->ti_flags;
+		
+		goto cont_conn;
+	}
+	
+	
+	tcpstat.tcps_rcvtotal++;
+	/*
+	 * Get IP and TCP header together in first mbuf.
+	 * Note: IP leaves IP header in first mbuf.
+	 */
+	ti = mtod(m, struct tcpiphdr *);
+	if (iphlen > sizeof(struct ip )) {
+	  ip_stripoptions(m, (struct mbuf *)0);
+	  iphlen=sizeof(struct ip );
+	}
+	/* XXX Check if too short */
+	
+
+	/*
+	 * Save a copy of the IP header in case we want restore it
+	 * for sending an ICMP error message in response.
+	 */
+	ip=mtod(m, struct ip *);
+	save_ip = *ip; 
+	save_ip.ip_len+= iphlen;
+
+	/*
+	 * Checksum extended TCP header and data.
+	 */
+	tlen = ((struct ip *)ti)->ip_len;
+	ti->ti_next = ti->ti_prev = 0;
+	ti->ti_x1 = 0;
+	ti->ti_len = htons((u_int16_t)tlen);
+	len = sizeof(struct ip ) + tlen;
+	/* keep checksum for ICMP reply
+	 * ti->ti_sum = cksum(m, len); 
+	 * if (ti->ti_sum) { */
+	if(cksum(m, len)) {
+	  tcpstat.tcps_rcvbadsum++;
+	  goto drop;
+	}
+
+	/*
+	 * Check that TCP offset makes sense,
+	 * pull out TCP options and adjust length.		XXX
+	 */
+	off = ti->ti_off << 2;
+	if (off < sizeof (struct tcphdr) || off > tlen) {
+	  tcpstat.tcps_rcvbadoff++;
+	  goto drop;
+	}
+	tlen -= off;
+	ti->ti_len = tlen;
+	if (off > sizeof (struct tcphdr)) {
+	  optlen = off - sizeof (struct tcphdr);
+	  optp = mtod(m, caddr_t) + sizeof (struct tcpiphdr);
+
+		/* 
+		 * Do quick retrieval of timestamp options ("options
+		 * prediction?").  If timestamp is the only option and it's
+		 * formatted as recommended in RFC 1323 appendix A, we
+		 * quickly get the values now and not bother calling
+		 * tcp_dooptions(), etc.
+		 */
+/*		if ((optlen == TCPOLEN_TSTAMP_APPA ||
+ *		     (optlen > TCPOLEN_TSTAMP_APPA &&
+ *			optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) &&
+ *		     *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) &&
+ *		     (ti->ti_flags & TH_SYN) == 0) {
+ *			ts_present = 1;
+ *			ts_val = ntohl(*(u_int32_t *)(optp + 4));
+ *			ts_ecr = ntohl(*(u_int32_t *)(optp + 8));
+ *			optp = NULL;   / * we've parsed the options * /
+ *		}
+ */
+	}
+	tiflags = ti->ti_flags;
+	
+	/*
+	 * Convert TCP protocol specific fields to host format.
+	 */
+	NTOHL(ti->ti_seq);
+	NTOHL(ti->ti_ack);
+	NTOHS(ti->ti_win);
+	NTOHS(ti->ti_urp);
+
+	/*
+	 * Drop TCP, IP headers and TCP options.
+	 */
+	m->m_data += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
+	m->m_len  -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
+	
+	/*
+	 * Locate pcb for segment.
+	 */
+findso:
+	so = tcp_last_so;
+	if (so->so_fport != ti->ti_dport ||
+	    so->so_lport != ti->ti_sport ||
+	    so->so_laddr.s_addr != ti->ti_src.s_addr ||
+	    so->so_faddr.s_addr != ti->ti_dst.s_addr) {
+		so = solookup(&tcb, ti->ti_src, ti->ti_sport,
+			       ti->ti_dst, ti->ti_dport);
+		if (so)
+			tcp_last_so = so;
+		++tcpstat.tcps_socachemiss;
+	}
+
+	/*
+	 * If the state is CLOSED (i.e., TCB does not exist) then
+	 * all data in the incoming segment is discarded.
+	 * If the TCB exists but is in CLOSED state, it is embryonic,
+	 * but should either do a listen or a connect soon.
+	 *
+	 * state == CLOSED means we've done socreate() but haven't
+	 * attached it to a protocol yet... 
+	 * 
+	 * XXX If a TCB does not exist, and the TH_SYN flag is
+	 * the only flag set, then create a session, mark it
+	 * as if it was LISTENING, and continue...
+	 */
+	if (so == 0) {
+	  if ((tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) != TH_SYN)
+	    goto dropwithreset;
+		
+	  if ((so = socreate()) == NULL)
+	    goto dropwithreset;
+	  if (tcp_attach(so) < 0) {
+	    free(so); /* Not sofree (if it failed, it's not insqued) */
+	    goto dropwithreset;
+	  }
+		
+	  sbreserve(&so->so_snd, tcp_sndspace);
+	  sbreserve(&so->so_rcv, tcp_rcvspace);
+	  
+	  /*		tcp_last_so = so; */  /* XXX ? */
+	  /*		tp = sototcpcb(so);    */
+		
+	  so->so_laddr = ti->ti_src;
+	  so->so_lport = ti->ti_sport;
+	  so->so_faddr = ti->ti_dst;
+	  so->so_fport = ti->ti_dport;
+		
+	  if ((so->so_iptos = tcp_tos(so)) == 0)
+	    so->so_iptos = ((struct ip *)ti)->ip_tos;
+		
+	  tp = sototcpcb(so);
+	  tp->t_state = TCPS_LISTEN;
+	}
+           
+        /*
+         * If this is a still-connecting socket, this probably
+         * a retransmit of the SYN.  Whether it's a retransmit SYN
+	 * or something else, we nuke it.
+         */
+        if (so->so_state & SS_ISFCONNECTING)
+                goto drop;
+
+	tp = sototcpcb(so);
+	
+	/* XXX Should never fail */
+	if (tp == 0)
+		goto dropwithreset;
+	if (tp->t_state == TCPS_CLOSED)
+		goto drop;
+	
+	/* Unscale the window into a 32-bit value. */
+/*	if ((tiflags & TH_SYN) == 0)
+ *		tiwin = ti->ti_win << tp->snd_scale;
+ *	else
+ */
+		tiwin = ti->ti_win;
+
+	/*
+	 * Segment received on connection.
+	 * Reset idle time and keep-alive timer.
+	 */
+	tp->t_idle = 0;
+	if (so_options)
+	   tp->t_timer[TCPT_KEEP] = tcp_keepintvl;
+	else
+	   tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+
+	/*
+	 * Process options if not in LISTEN state,
+	 * else do it below (after getting remote address).
+	 */
+	if (optp && tp->t_state != TCPS_LISTEN)
+		tcp_dooptions(tp, (u_char *)optp, optlen, ti); 
+/* , */
+/*			&ts_present, &ts_val, &ts_ecr); */
+
+	/* 
+	 * Header prediction: check for the two common cases
+	 * of a uni-directional data xfer.  If the packet has
+	 * no control flags, is in-sequence, the window didn't
+	 * change and we're not retransmitting, it's a
+	 * candidate.  If the length is zero and the ack moved
+	 * forward, we're the sender side of the xfer.  Just
+	 * free the data acked & wake any higher level process
+	 * that was blocked waiting for space.  If the length
+	 * is non-zero and the ack didn't move, we're the
+	 * receiver side.  If we're getting packets in-order
+	 * (the reassembly queue is empty), add the data to
+	 * the socket buffer and note that we need a delayed ack.
+	 *
+	 * XXX Some of these tests are not needed
+	 * eg: the tiwin == tp->snd_wnd prevents many more
+	 * predictions.. with no *real* advantage..
+	 */
+	if (tp->t_state == TCPS_ESTABLISHED &&
+	    (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
+/*	    (!ts_present || TSTMP_GEQ(ts_val, tp->ts_recent)) && */
+	    ti->ti_seq == tp->rcv_nxt &&
+	    tiwin && tiwin == tp->snd_wnd &&
+	    tp->snd_nxt == tp->snd_max) {
+		/* 
+		 * If last ACK falls within this segment's sequence numbers,
+		 *  record the timestamp.
+		 */
+/*		if (ts_present && SEQ_LEQ(ti->ti_seq, tp->last_ack_sent) &&
+ *		   SEQ_LT(tp->last_ack_sent, ti->ti_seq + ti->ti_len)) {
+ *			tp->ts_recent_age = tcp_now;
+ *			tp->ts_recent = ts_val;
+ *		}
+ */
+		if (ti->ti_len == 0) {
+			if (SEQ_GT(ti->ti_ack, tp->snd_una) &&
+			    SEQ_LEQ(ti->ti_ack, tp->snd_max) &&
+			    tp->snd_cwnd >= tp->snd_wnd) {
+				/*
+				 * this is a pure ack for outstanding data.
+				 */
+				++tcpstat.tcps_predack;
+/*				if (ts_present)
+ *					tcp_xmit_timer(tp, tcp_now-ts_ecr+1);
+ *				else 
+ */				     if (tp->t_rtt &&
+					    SEQ_GT(ti->ti_ack, tp->t_rtseq))
+					tcp_xmit_timer(tp, tp->t_rtt);
+				acked = ti->ti_ack - tp->snd_una;
+				tcpstat.tcps_rcvackpack++;
+				tcpstat.tcps_rcvackbyte += acked;
+				sbdrop(&so->so_snd, acked);
+				tp->snd_una = ti->ti_ack;
+				m_freem(m);
+
+				/*
+				 * If all outstanding data are acked, stop
+				 * retransmit timer, otherwise restart timer
+				 * using current (possibly backed-off) value.
+				 * If process is waiting for space,
+				 * wakeup/selwakeup/signal.  If data
+				 * are ready to send, let tcp_output
+				 * decide between more output or persist.
+				 */
+				if (tp->snd_una == tp->snd_max)
+					tp->t_timer[TCPT_REXMT] = 0;
+				else if (tp->t_timer[TCPT_PERSIST] == 0)
+					tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+
+				/* 
+				 * There's room in so_snd, sowwakup will read()
+				 * from the socket if we can
+				 */
+/*				if (so->so_snd.sb_flags & SB_NOTIFY)
+ *					sowwakeup(so);
+ */
+				/* 
+				 * This is called because sowwakeup might have
+				 * put data into so_snd.  Since we don't so sowwakeup,
+				 * we don't need this.. XXX???
+				 */
+				if (so->so_snd.sb_cc)
+					(void) tcp_output(tp);
+
+				return;
+			}
+		} else if (ti->ti_ack == tp->snd_una &&
+		    tp->seg_next == (tcpiphdrp_32)tp &&
+		    ti->ti_len <= sbspace(&so->so_rcv)) {
+			/*
+			 * this is a pure, in-sequence data packet
+			 * with nothing on the reassembly queue and
+			 * we have enough buffer space to take it.
+			 */
+			++tcpstat.tcps_preddat;
+			tp->rcv_nxt += ti->ti_len;
+			tcpstat.tcps_rcvpack++;
+			tcpstat.tcps_rcvbyte += ti->ti_len;
+			/*
+			 * Add data to socket buffer.
+			 */
+			if (so->so_emu) {
+				if (tcp_emu(so,m)) sbappend(so, m);
+			} else
+				sbappend(so, m);
+			
+			/* 
+			 * XXX This is called when data arrives.  Later, check
+			 * if we can actually write() to the socket
+			 * XXX Need to check? It's be NON_BLOCKING
+			 */
+/*			sorwakeup(so); */
+			
+			/*
+			 * If this is a short packet, then ACK now - with Nagel
+			 *	congestion avoidance sender won't send more until
+			 *	he gets an ACK.
+			 * 
+			 * Here are 3 interpretations of what should happen.
+			 * The best (for me) is to delay-ack everything except
+			 * if it's a one-byte packet containing an ESC
+			 * (this means it's an arrow key (or similar) sent using
+			 * Nagel, hence there will be no echo)
+			 * The first of these is the original, the second is the
+			 * middle ground between the other 2
+			 */ 
+/*			if (((unsigned)ti->ti_len < tp->t_maxseg)) {
+ */			     
+/*			if (((unsigned)ti->ti_len < tp->t_maxseg && 
+ *			     (so->so_iptos & IPTOS_LOWDELAY) == 0) ||
+ *			    ((so->so_iptos & IPTOS_LOWDELAY) && 
+ *			     ((struct tcpiphdr_2 *)ti)->first_char == (char)27)) {
+ */
+			if ((unsigned)ti->ti_len == 1 &&
+			    ((struct tcpiphdr_2 *)ti)->first_char == (char)27) {
+				tp->t_flags |= TF_ACKNOW;
+				tcp_output(tp);
+			} else {
+				tp->t_flags |= TF_DELACK;
+			}
+			return;
+		}
+	} /* header prediction */
+	/*
+	 * Calculate amount of space in receive window,
+	 * and then do TCP input processing.
+	 * Receive window is amount of space in rcv queue,
+	 * but not less than advertised window.
+	 */
+	{ int win;
+          win = sbspace(&so->so_rcv);
+	  if (win < 0)
+	    win = 0;
+	  tp->rcv_wnd = max(win, (int)(tp->rcv_adv - tp->rcv_nxt));
+	}
+
+	switch (tp->t_state) {
+
+	/*
+	 * If the state is LISTEN then ignore segment if it contains an RST.
+	 * If the segment contains an ACK then it is bad and send a RST.
+	 * If it does not contain a SYN then it is not interesting; drop it.
+	 * Don't bother responding if the destination was a broadcast.
+	 * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
+	 * tp->iss, and send a segment:
+	 *     <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
+	 * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
+	 * Fill in remote peer address fields if not previously specified.
+	 * Enter SYN_RECEIVED state, and process any other fields of this
+	 * segment in this state.
+	 */
+	case TCPS_LISTEN: {
+
+	  if (tiflags & TH_RST)
+	    goto drop;
+	  if (tiflags & TH_ACK)
+	    goto dropwithreset;
+	  if ((tiflags & TH_SYN) == 0)
+	    goto drop;
+		
+	  /*
+	   * This has way too many gotos...
+	   * But a bit of spaghetti code never hurt anybody :)
+	   */
+	  
+	  /*
+	   * If this is destined for the control address, then flag to
+	   * tcp_ctl once connected, otherwise connect
+	   */
+	  if ((so->so_faddr.s_addr&htonl(0xffffff00)) == special_addr.s_addr) {
+	    int lastbyte=ntohl(so->so_faddr.s_addr) & 0xff;
+	    if (lastbyte!=CTL_ALIAS && lastbyte!=CTL_DNS) {
+#if 0
+	      if(lastbyte==CTL_CMD || lastbyte==CTL_EXEC) {
+		/* Command or exec adress */
+		so->so_state |= SS_CTL;
+	      } else {
+		/* May be an add exec */
+		struct ex_list *ex_ptr;
+
+		for(ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
+		  if(ex_ptr->ex_fport == so->so_fport && 
+		     lastbyte == ex_ptr->ex_addr) {
+		    so->so_state |= SS_CTL;
+		    break;
+		  }
+		}
+	      }
+	      if(so->so_state & SS_CTL) goto cont_input;
+#endif
+	    }
+	    /* CTL_ALIAS: Do nothing, tcp_fconnect will be called on it */
+	  }
+	  
+	  if (so->so_emu & EMU_NOCONNECT) {
+	    so->so_emu &= ~EMU_NOCONNECT;
+	    goto cont_input;
+	  }
+	  
+	  if(tcp_fconnect(so) == -1 && errno != EINPROGRESS) {
+	    u_char code=ICMP_UNREACH_NET;
+	    DEBUG_MISC((dfd," tcp fconnect errno = %d-%s\n",
+			errno,strerror(errno)));
+	    if(errno == ECONNREFUSED) {
+	      /* ACK the SYN, send RST to refuse the connection */
+	      tcp_respond(tp, ti, m, ti->ti_seq+1, (tcp_seq)0,
+			  TH_RST|TH_ACK); 
+	    } else {
+	      if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
+	      HTONL(ti->ti_seq);             /* restore tcp header */
+	      HTONL(ti->ti_ack);
+	      HTONS(ti->ti_win);
+	      HTONS(ti->ti_urp);
+	      m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
+	      m->m_len  += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
+	      *ip=save_ip;
+	      icmp_error(m, ICMP_UNREACH,code, 0,strerror(errno));
+	    }
+	    tp = tcp_close(tp);
+	    m_free(m);
+	  } else {
+	    /*
+	     * Haven't connected yet, save the current mbuf
+	     * and ti, and return
+	     * XXX Some OS's don't tell us whether the connect()
+	     * succeeded or not.  So we must time it out.
+	     */
+	    so->so_m = m;
+	    so->so_ti = ti;
+	    tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
+	    tp->t_state = TCPS_SYN_RECEIVED;
+	  }
+	  return;
+
+	cont_conn:     
+	  /* m==NULL 
+	   * Check if the connect succeeded
+	   */
+	  if (so->so_state & SS_NOFDREF) {
+	    tp = tcp_close(tp);
+	    goto dropwithreset;
+	  }
+	cont_input:		
+	  tcp_template(tp);
+	  
+	  if (optp)
+	    tcp_dooptions(tp, (u_char *)optp, optlen, ti);
+	  /* , */
+	  /*				&ts_present, &ts_val, &ts_ecr); */
+	  
+	  if (iss)
+	    tp->iss = iss;
+	  else 
+	    tp->iss = tcp_iss;
+	  tcp_iss += TCP_ISSINCR/2;
+	  tp->irs = ti->ti_seq;
+	  tcp_sendseqinit(tp);
+	  tcp_rcvseqinit(tp);
+	  tp->t_flags |= TF_ACKNOW;
+	  tp->t_state = TCPS_SYN_RECEIVED;
+	  tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
+	  tcpstat.tcps_accepts++;
+	  goto trimthenstep6;
+	} /* case TCPS_LISTEN */
+	
+	/*
+	 * If the state is SYN_SENT:
+	 *	if seg contains an ACK, but not for our SYN, drop the input.
+	 *	if seg contains a RST, then drop the connection.
+	 *	if seg does not contain SYN, then drop it.
+	 * Otherwise this is an acceptable SYN segment
+	 *	initialize tp->rcv_nxt and tp->irs
+	 *	if seg contains ack then advance tp->snd_una
+	 *	if SYN has been acked change to ESTABLISHED else SYN_RCVD state
+	 *	arrange for segment to be acked (eventually)
+	 *	continue processing rest of data/controls, beginning with URG
+	 */
+	case TCPS_SYN_SENT:
+		if ((tiflags & TH_ACK) &&
+		    (SEQ_LEQ(ti->ti_ack, tp->iss) ||
+		     SEQ_GT(ti->ti_ack, tp->snd_max)))
+			goto dropwithreset;
+
+		if (tiflags & TH_RST) {
+			if (tiflags & TH_ACK)
+				tp = tcp_drop(tp,0); /* XXX Check t_softerror! */
+			goto drop;
+		}
+
+		if ((tiflags & TH_SYN) == 0)
+			goto drop;
+		if (tiflags & TH_ACK) {
+			tp->snd_una = ti->ti_ack;
+			if (SEQ_LT(tp->snd_nxt, tp->snd_una))
+				tp->snd_nxt = tp->snd_una;
+		}
+
+		tp->t_timer[TCPT_REXMT] = 0;
+		tp->irs = ti->ti_seq;
+		tcp_rcvseqinit(tp);
+		tp->t_flags |= TF_ACKNOW;
+		if (tiflags & TH_ACK && SEQ_GT(tp->snd_una, tp->iss)) {
+			tcpstat.tcps_connects++;
+			soisfconnected(so);
+			tp->t_state = TCPS_ESTABLISHED;
+			
+			/* Do window scaling on this connection? */
+/*			if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
+ *				(TF_RCVD_SCALE|TF_REQ_SCALE)) {
+ * 				tp->snd_scale = tp->requested_s_scale;
+ *				tp->rcv_scale = tp->request_r_scale;
+ *			}
+ */
+			(void) tcp_reass(tp, (struct tcpiphdr *)0,
+				(struct mbuf *)0);
+			/*
+			 * if we didn't have to retransmit the SYN,
+			 * use its rtt as our initial srtt & rtt var.
+			 */
+			if (tp->t_rtt)
+				tcp_xmit_timer(tp, tp->t_rtt);
+		} else
+			tp->t_state = TCPS_SYN_RECEIVED;
+
+trimthenstep6:
+		/*
+		 * Advance ti->ti_seq to correspond to first data byte.
+		 * If data, trim to stay within window,
+		 * dropping FIN if necessary.
+		 */
+		ti->ti_seq++;
+		if (ti->ti_len > tp->rcv_wnd) {
+			todrop = ti->ti_len - tp->rcv_wnd;
+			m_adj(m, -todrop);
+			ti->ti_len = tp->rcv_wnd;
+			tiflags &= ~TH_FIN;
+			tcpstat.tcps_rcvpackafterwin++;
+			tcpstat.tcps_rcvbyteafterwin += todrop;
+		}
+		tp->snd_wl1 = ti->ti_seq - 1;
+		tp->rcv_up = ti->ti_seq;
+		goto step6;
+	} /* switch tp->t_state */
+	/*
+	 * States other than LISTEN or SYN_SENT.
+	 * First check timestamp, if present.
+	 * Then check that at least some bytes of segment are within 
+	 * receive window.  If segment begins before rcv_nxt,
+	 * drop leading data (and SYN); if nothing left, just ack.
+	 * 
+	 * RFC 1323 PAWS: If we have a timestamp reply on this segment
+	 * and it's less than ts_recent, drop it.
+	 */
+/*	if (ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent &&
+ *	    TSTMP_LT(ts_val, tp->ts_recent)) {
+ *
+ */		/* Check to see if ts_recent is over 24 days old.  */
+/*		if ((int)(tcp_now - tp->ts_recent_age) > TCP_PAWS_IDLE) {
+ */			/*
+ *			 * Invalidate ts_recent.  If this segment updates
+ *			 * ts_recent, the age will be reset later and ts_recent
+ *			 * will get a valid value.  If it does not, setting
+ *			 * ts_recent to zero will at least satisfy the
+ *			 * requirement that zero be placed in the timestamp
+ *			 * echo reply when ts_recent isn't valid.  The
+ *			 * age isn't reset until we get a valid ts_recent
+ *			 * because we don't want out-of-order segments to be
+ *			 * dropped when ts_recent is old.
+ *			 */
+/*			tp->ts_recent = 0;
+ *		} else {
+ *			tcpstat.tcps_rcvduppack++;
+ *			tcpstat.tcps_rcvdupbyte += ti->ti_len;
+ *			tcpstat.tcps_pawsdrop++;
+ *			goto dropafterack;
+ *		}
+ *	}
+ */
+
+	todrop = tp->rcv_nxt - ti->ti_seq;
+	if (todrop > 0) {
+		if (tiflags & TH_SYN) {
+			tiflags &= ~TH_SYN;
+			ti->ti_seq++;
+			if (ti->ti_urp > 1) 
+				ti->ti_urp--;
+			else
+				tiflags &= ~TH_URG;
+			todrop--;
+		}
+		/*
+		 * Following if statement from Stevens, vol. 2, p. 960.
+		 */
+		if (todrop > ti->ti_len
+		    || (todrop == ti->ti_len && (tiflags & TH_FIN) == 0)) {
+			/*
+			 * Any valid FIN must be to the left of the window.
+			 * At this point the FIN must be a duplicate or out
+			 * of sequence; drop it.
+			 */
+			tiflags &= ~TH_FIN;
+			
+			/*
+			 * Send an ACK to resynchronize and drop any data.
+			 * But keep on processing for RST or ACK.
+			 */
+			tp->t_flags |= TF_ACKNOW;
+			todrop = ti->ti_len;
+			tcpstat.tcps_rcvduppack++;
+			tcpstat.tcps_rcvdupbyte += todrop;
+		} else {
+			tcpstat.tcps_rcvpartduppack++;
+			tcpstat.tcps_rcvpartdupbyte += todrop;
+		}
+		m_adj(m, todrop);
+		ti->ti_seq += todrop;
+		ti->ti_len -= todrop;
+		if (ti->ti_urp > todrop)
+			ti->ti_urp -= todrop;
+		else {
+			tiflags &= ~TH_URG;
+			ti->ti_urp = 0;
+		}
+	}
+	/*
+	 * If new data are received on a connection after the
+	 * user processes are gone, then RST the other end.
+	 */
+	if ((so->so_state & SS_NOFDREF) &&
+	    tp->t_state > TCPS_CLOSE_WAIT && ti->ti_len) {
+		tp = tcp_close(tp);
+		tcpstat.tcps_rcvafterclose++;
+		goto dropwithreset;
+	}
+
+	/*
+	 * If segment ends after window, drop trailing data
+	 * (and PUSH and FIN); if nothing left, just ACK.
+	 */
+	todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd);
+	if (todrop > 0) {
+		tcpstat.tcps_rcvpackafterwin++;
+		if (todrop >= ti->ti_len) {
+			tcpstat.tcps_rcvbyteafterwin += ti->ti_len;
+			/*
+			 * If a new connection request is received
+			 * while in TIME_WAIT, drop the old connection
+			 * and start over if the sequence numbers
+			 * are above the previous ones.
+			 */
+			if (tiflags & TH_SYN &&
+			    tp->t_state == TCPS_TIME_WAIT &&
+			    SEQ_GT(ti->ti_seq, tp->rcv_nxt)) {
+				iss = tp->rcv_nxt + TCP_ISSINCR;
+				tp = tcp_close(tp);
+				goto findso;
+			}
+			/*
+			 * If window is closed can only take segments at
+			 * window edge, and have to drop data and PUSH from
+			 * incoming segments.  Continue processing, but
+			 * remember to ack.  Otherwise, drop segment
+			 * and ack.
+			 */
+			if (tp->rcv_wnd == 0 && ti->ti_seq == tp->rcv_nxt) {
+				tp->t_flags |= TF_ACKNOW;
+				tcpstat.tcps_rcvwinprobe++;
+			} else
+				goto dropafterack;
+		} else
+			tcpstat.tcps_rcvbyteafterwin += todrop;
+		m_adj(m, -todrop);
+		ti->ti_len -= todrop;
+		tiflags &= ~(TH_PUSH|TH_FIN);
+	}
+
+	/*
+	 * If last ACK falls within this segment's sequence numbers,
+	 * record its timestamp.
+	 */
+/*	if (ts_present && SEQ_LEQ(ti->ti_seq, tp->last_ack_sent) &&
+ *	    SEQ_LT(tp->last_ack_sent, ti->ti_seq + ti->ti_len +
+ *		   ((tiflags & (TH_SYN|TH_FIN)) != 0))) {
+ *		tp->ts_recent_age = tcp_now;
+ *		tp->ts_recent = ts_val;
+ *	}
+ */
+
+	/*
+	 * If the RST bit is set examine the state:
+	 *    SYN_RECEIVED STATE:
+	 *	If passive open, return to LISTEN state.
+	 *	If active open, inform user that connection was refused.
+	 *    ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:
+	 *	Inform user that connection was reset, and close tcb.
+	 *    CLOSING, LAST_ACK, TIME_WAIT STATES
+	 *	Close the tcb.
+	 */
+	if (tiflags&TH_RST) switch (tp->t_state) {
+
+	case TCPS_SYN_RECEIVED:
+/*		so->so_error = ECONNREFUSED; */
+		goto close;
+
+	case TCPS_ESTABLISHED:
+	case TCPS_FIN_WAIT_1:
+	case TCPS_FIN_WAIT_2:
+	case TCPS_CLOSE_WAIT:
+/*		so->so_error = ECONNRESET; */
+	close:
+		tp->t_state = TCPS_CLOSED;
+		tcpstat.tcps_drops++;
+		tp = tcp_close(tp);
+		goto drop;
+
+	case TCPS_CLOSING:
+	case TCPS_LAST_ACK:
+	case TCPS_TIME_WAIT:
+		tp = tcp_close(tp);
+		goto drop;
+	}
+
+	/*
+	 * If a SYN is in the window, then this is an
+	 * error and we send an RST and drop the connection.
+	 */
+	if (tiflags & TH_SYN) {
+		tp = tcp_drop(tp,0);
+		goto dropwithreset;
+	}
+
+	/*
+	 * If the ACK bit is off we drop the segment and return.
+	 */
+	if ((tiflags & TH_ACK) == 0) goto drop;
+
+	/*
+	 * Ack processing.
+	 */
+	switch (tp->t_state) {
+	/*
+	 * In SYN_RECEIVED state if the ack ACKs our SYN then enter
+	 * ESTABLISHED state and continue processing, otherwise
+	 * send an RST.  una<=ack<=max
+	 */
+	case TCPS_SYN_RECEIVED:
+
+		if (SEQ_GT(tp->snd_una, ti->ti_ack) ||
+		    SEQ_GT(ti->ti_ack, tp->snd_max))
+			goto dropwithreset;
+		tcpstat.tcps_connects++;
+		tp->t_state = TCPS_ESTABLISHED;
+		/* 
+		 * The sent SYN is ack'ed with our sequence number +1 
+		 * The first data byte already in the buffer will get 
+		 * lost if no correction is made.  This is only needed for
+		 * SS_CTL since the buffer is empty otherwise.
+		 * tp->snd_una++; or:     
+		 */
+		tp->snd_una=ti->ti_ack;
+		if (so->so_state & SS_CTL) {
+		  /* So tcp_ctl reports the right state */
+		  ret = tcp_ctl(so);
+		  if (ret == 1) {
+		    soisfconnected(so);
+		    so->so_state &= ~SS_CTL;   /* success XXX */
+		  } else if (ret == 2) {
+		    so->so_state = SS_NOFDREF; /* CTL_CMD */
+		  } else {
+		    needoutput = 1;
+		    tp->t_state = TCPS_FIN_WAIT_1;
+		  }
+		} else {
+		  soisfconnected(so);
+		}
+		
+		/* Do window scaling? */
+/*		if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
+ *			(TF_RCVD_SCALE|TF_REQ_SCALE)) {
+ *			tp->snd_scale = tp->requested_s_scale;
+ *			tp->rcv_scale = tp->request_r_scale;
+ *		}
+ */
+		(void) tcp_reass(tp, (struct tcpiphdr *)0, (struct mbuf *)0);
+		tp->snd_wl1 = ti->ti_seq - 1;
+		/* Avoid ack processing; snd_una==ti_ack  =>  dup ack */
+		goto synrx_to_est;
+		/* fall into ... */
+
+	/*
+	 * In ESTABLISHED state: drop duplicate ACKs; ACK out of range
+	 * ACKs.  If the ack is in the range
+	 *	tp->snd_una < ti->ti_ack <= tp->snd_max
+	 * then advance tp->snd_una to ti->ti_ack and drop
+	 * data from the retransmission queue.  If this ACK reflects
+	 * more up to date window information we update our window information.
+	 */
+	case TCPS_ESTABLISHED:
+	case TCPS_FIN_WAIT_1:
+	case TCPS_FIN_WAIT_2:
+	case TCPS_CLOSE_WAIT:
+	case TCPS_CLOSING:
+	case TCPS_LAST_ACK:
+	case TCPS_TIME_WAIT:
+
+		if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) {
+			if (ti->ti_len == 0 && tiwin == tp->snd_wnd) {
+			  tcpstat.tcps_rcvdupack++;
+			  DEBUG_MISC((dfd," dup ack  m = %lx  so = %lx \n",
+				      (long )m, (long )so));
+				/*
+				 * If we have outstanding data (other than
+				 * a window probe), this is a completely
+				 * duplicate ack (ie, window info didn't
+				 * change), the ack is the biggest we've
+				 * seen and we've seen exactly our rexmt
+				 * threshold of them, assume a packet
+				 * has been dropped and retransmit it.
+				 * Kludge snd_nxt & the congestion
+				 * window so we send only this one
+				 * packet.
+				 *
+				 * We know we're losing at the current
+				 * window size so do congestion avoidance
+				 * (set ssthresh to half the current window
+				 * and pull our congestion window back to
+				 * the new ssthresh).
+				 *
+				 * Dup acks mean that packets have left the
+				 * network (they're now cached at the receiver) 
+				 * so bump cwnd by the amount in the receiver
+				 * to keep a constant cwnd packets in the
+				 * network.
+				 */
+				if (tp->t_timer[TCPT_REXMT] == 0 ||
+				    ti->ti_ack != tp->snd_una)
+					tp->t_dupacks = 0;
+				else if (++tp->t_dupacks == tcprexmtthresh) {
+					tcp_seq onxt = tp->snd_nxt;
+					u_int win =
+					    min(tp->snd_wnd, tp->snd_cwnd) / 2 /
+						tp->t_maxseg;
+
+					if (win < 2)
+						win = 2;
+					tp->snd_ssthresh = win * tp->t_maxseg;
+					tp->t_timer[TCPT_REXMT] = 0;
+					tp->t_rtt = 0;
+					tp->snd_nxt = ti->ti_ack;
+					tp->snd_cwnd = tp->t_maxseg;
+					(void) tcp_output(tp);
+					tp->snd_cwnd = tp->snd_ssthresh +
+					       tp->t_maxseg * tp->t_dupacks;
+					if (SEQ_GT(onxt, tp->snd_nxt))
+						tp->snd_nxt = onxt;
+					goto drop;
+				} else if (tp->t_dupacks > tcprexmtthresh) {
+					tp->snd_cwnd += tp->t_maxseg;
+					(void) tcp_output(tp);
+					goto drop;
+				}
+			} else
+				tp->t_dupacks = 0;
+			break;
+		}
+	synrx_to_est:
+		/*
+		 * If the congestion window was inflated to account
+		 * for the other side's cached packets, retract it.
+		 */
+		if (tp->t_dupacks > tcprexmtthresh &&
+		    tp->snd_cwnd > tp->snd_ssthresh)
+			tp->snd_cwnd = tp->snd_ssthresh;
+		tp->t_dupacks = 0;
+		if (SEQ_GT(ti->ti_ack, tp->snd_max)) {
+			tcpstat.tcps_rcvacktoomuch++;
+			goto dropafterack;
+		}
+		acked = ti->ti_ack - tp->snd_una;
+		tcpstat.tcps_rcvackpack++;
+		tcpstat.tcps_rcvackbyte += acked;
+
+		/*
+		 * If we have a timestamp reply, update smoothed
+		 * round trip time.  If no timestamp is present but
+		 * transmit timer is running and timed sequence
+		 * number was acked, update smoothed round trip time.
+		 * Since we now have an rtt measurement, cancel the
+		 * timer backoff (cf., Phil Karn's retransmit alg.).
+		 * Recompute the initial retransmit timer.
+		 */
+/*		if (ts_present)
+ *			tcp_xmit_timer(tp, tcp_now-ts_ecr+1);
+ *		else
+ */		     
+		     if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq))
+			tcp_xmit_timer(tp,tp->t_rtt);
+
+		/*
+		 * If all outstanding data is acked, stop retransmit
+		 * timer and remember to restart (more output or persist).
+		 * If there is more data to be acked, restart retransmit
+		 * timer, using current (possibly backed-off) value.
+		 */
+		if (ti->ti_ack == tp->snd_max) {
+			tp->t_timer[TCPT_REXMT] = 0;
+			needoutput = 1;
+		} else if (tp->t_timer[TCPT_PERSIST] == 0)
+			tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+		/*
+		 * When new data is acked, open the congestion window.
+		 * If the window gives us less than ssthresh packets
+		 * in flight, open exponentially (maxseg per packet).
+		 * Otherwise open linearly: maxseg per window
+		 * (maxseg^2 / cwnd per packet).
+		 */
+		{
+		  register u_int cw = tp->snd_cwnd;
+		  register u_int incr = tp->t_maxseg;
+
+		  if (cw > tp->snd_ssthresh)
+		    incr = incr * incr / cw;
+		  tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale);
+		}
+		if (acked > so->so_snd.sb_cc) {
+			tp->snd_wnd -= so->so_snd.sb_cc;
+			sbdrop(&so->so_snd, (int )so->so_snd.sb_cc);
+			ourfinisacked = 1;
+		} else {
+			sbdrop(&so->so_snd, acked);
+			tp->snd_wnd -= acked;
+			ourfinisacked = 0;
+		}
+		/*
+		 * XXX sowwakup is called when data is acked and there's room for
+		 * for more data... it should read() the socket 
+		 */
+/*		if (so->so_snd.sb_flags & SB_NOTIFY)
+ *			sowwakeup(so);
+ */
+		tp->snd_una = ti->ti_ack;
+		if (SEQ_LT(tp->snd_nxt, tp->snd_una))
+			tp->snd_nxt = tp->snd_una;
+
+		switch (tp->t_state) {
+
+		/*
+		 * In FIN_WAIT_1 STATE in addition to the processing
+		 * for the ESTABLISHED state if our FIN is now acknowledged
+		 * then enter FIN_WAIT_2.
+		 */
+		case TCPS_FIN_WAIT_1:
+			if (ourfinisacked) {
+				/*
+				 * If we can't receive any more
+				 * data, then closing user can proceed.
+				 * Starting the timer is contrary to the
+				 * specification, but if we don't get a FIN
+				 * we'll hang forever.
+				 */
+				if (so->so_state & SS_FCANTRCVMORE) {
+					soisfdisconnected(so);
+					tp->t_timer[TCPT_2MSL] = tcp_maxidle;
+				}
+				tp->t_state = TCPS_FIN_WAIT_2;
+			}
+			break;
+
+	 	/*
+		 * In CLOSING STATE in addition to the processing for
+		 * the ESTABLISHED state if the ACK acknowledges our FIN
+		 * then enter the TIME-WAIT state, otherwise ignore
+		 * the segment.
+		 */
+		case TCPS_CLOSING:
+			if (ourfinisacked) {
+				tp->t_state = TCPS_TIME_WAIT;
+				tcp_canceltimers(tp);
+				tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+				soisfdisconnected(so);
+			}
+			break;
+
+		/*
+		 * In LAST_ACK, we may still be waiting for data to drain
+		 * and/or to be acked, as well as for the ack of our FIN.
+		 * If our FIN is now acknowledged, delete the TCB,
+		 * enter the closed state and return.
+		 */
+		case TCPS_LAST_ACK:
+			if (ourfinisacked) {
+				tp = tcp_close(tp);
+				goto drop;
+			}
+			break;
+
+		/*
+		 * In TIME_WAIT state the only thing that should arrive
+		 * is a retransmission of the remote FIN.  Acknowledge
+		 * it and restart the finack timer.
+		 */
+		case TCPS_TIME_WAIT:
+			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+			goto dropafterack;
+		}
+	} /* switch(tp->t_state) */
+
+step6:
+	/*
+	 * Update window information.
+	 * Don't look at window if no ACK: TAC's send garbage on first SYN.
+	 */
+	if ((tiflags & TH_ACK) &&
+	    (SEQ_LT(tp->snd_wl1, ti->ti_seq) || 
+	    (tp->snd_wl1 == ti->ti_seq && (SEQ_LT(tp->snd_wl2, ti->ti_ack) ||
+	    (tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd))))) {
+		/* keep track of pure window updates */
+		if (ti->ti_len == 0 &&
+		    tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd)
+			tcpstat.tcps_rcvwinupd++;
+		tp->snd_wnd = tiwin;
+		tp->snd_wl1 = ti->ti_seq;
+		tp->snd_wl2 = ti->ti_ack;
+		if (tp->snd_wnd > tp->max_sndwnd)
+			tp->max_sndwnd = tp->snd_wnd;
+		needoutput = 1;
+	}
+
+	/*
+	 * Process segments with URG.
+	 */
+	if ((tiflags & TH_URG) && ti->ti_urp &&
+	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+		/*
+		 * This is a kludge, but if we receive and accept
+		 * random urgent pointers, we'll crash in
+		 * soreceive.  It's hard to imagine someone
+		 * actually wanting to send this much urgent data.
+		 */
+		if (ti->ti_urp + so->so_rcv.sb_cc > so->so_rcv.sb_datalen) {
+			ti->ti_urp = 0;
+			tiflags &= ~TH_URG;
+			goto dodata;
+		}
+		/*
+		 * If this segment advances the known urgent pointer,
+		 * then mark the data stream.  This should not happen
+		 * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
+		 * a FIN has been received from the remote side. 
+		 * In these states we ignore the URG.
+		 *
+		 * According to RFC961 (Assigned Protocols),
+		 * the urgent pointer points to the last octet
+		 * of urgent data.  We continue, however,
+		 * to consider it to indicate the first octet
+		 * of data past the urgent section as the original 
+		 * spec states (in one of two places).
+		 */
+		if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) {
+			tp->rcv_up = ti->ti_seq + ti->ti_urp;
+			so->so_urgc =  so->so_rcv.sb_cc +
+				(tp->rcv_up - tp->rcv_nxt); /* -1; */
+			tp->rcv_up = ti->ti_seq + ti->ti_urp;
+	 
+		}
+	} else
+		/*
+		 * If no out of band data is expected,
+		 * pull receive urgent pointer along
+		 * with the receive window.
+		 */
+		if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
+			tp->rcv_up = tp->rcv_nxt;
+dodata:
+
+	/*
+	 * Process the segment text, merging it into the TCP sequencing queue,
+	 * and arranging for acknowledgment of receipt if necessary.
+	 * This process logically involves adjusting tp->rcv_wnd as data
+	 * is presented to the user (this happens in tcp_usrreq.c,
+	 * case PRU_RCVD).  If a FIN has already been received on this
+	 * connection then we just ignore the text.
+	 */
+	if ((ti->ti_len || (tiflags&TH_FIN)) &&
+	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+		TCP_REASS(tp, ti, m, so, tiflags);
+		/*
+		 * Note the amount of data that peer has sent into
+		 * our window, in order to estimate the sender's
+		 * buffer size.
+		 */
+		len = so->so_rcv.sb_datalen - (tp->rcv_adv - tp->rcv_nxt);
+	} else {
+		m_free(m);
+		tiflags &= ~TH_FIN;
+	}
+
+	/*
+	 * If FIN is received ACK the FIN and let the user know
+	 * that the connection is closing.
+	 */
+	if (tiflags & TH_FIN) {
+		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+			/*
+			 * If we receive a FIN we can't send more data,
+			 * set it SS_FDRAIN
+                         * Shutdown the socket if there is no rx data in the
+			 * buffer.
+			 * soread() is called on completion of shutdown() and
+			 * will got to TCPS_LAST_ACK, and use tcp_output()
+			 * to send the FIN.
+			 */
+/*			sofcantrcvmore(so); */
+			sofwdrain(so);
+			
+			tp->t_flags |= TF_ACKNOW;
+			tp->rcv_nxt++;
+		}
+		switch (tp->t_state) {
+
+	 	/*
+		 * In SYN_RECEIVED and ESTABLISHED STATES
+		 * enter the CLOSE_WAIT state.
+		 */
+		case TCPS_SYN_RECEIVED:
+		case TCPS_ESTABLISHED:
+		  if(so->so_emu == EMU_CTL)        /* no shutdown on socket */
+		    tp->t_state = TCPS_LAST_ACK;
+		  else 
+		    tp->t_state = TCPS_CLOSE_WAIT;
+		  break;
+
+	 	/*
+		 * If still in FIN_WAIT_1 STATE FIN has not been acked so
+		 * enter the CLOSING state.
+		 */
+		case TCPS_FIN_WAIT_1:
+			tp->t_state = TCPS_CLOSING;
+			break;
+
+	 	/*
+		 * In FIN_WAIT_2 state enter the TIME_WAIT state,
+		 * starting the time-wait timer, turning off the other 
+		 * standard timers.
+		 */
+		case TCPS_FIN_WAIT_2:
+			tp->t_state = TCPS_TIME_WAIT;
+			tcp_canceltimers(tp);
+			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+			soisfdisconnected(so);
+			break;
+
+		/*
+		 * In TIME_WAIT state restart the 2 MSL time_wait timer.
+		 */
+		case TCPS_TIME_WAIT:
+			tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+			break;
+		}
+	}
+
+	/*
+	 * If this is a small packet, then ACK now - with Nagel
+	 *      congestion avoidance sender won't send more until
+	 *      he gets an ACK.
+	 * 
+	 * See above.
+	 */
+/*	if (ti->ti_len && (unsigned)ti->ti_len < tp->t_maxseg) {
+ */
+/*	if ((ti->ti_len && (unsigned)ti->ti_len < tp->t_maxseg &&
+ *		(so->so_iptos & IPTOS_LOWDELAY) == 0) ||
+ *	       ((so->so_iptos & IPTOS_LOWDELAY) &&
+ *	       ((struct tcpiphdr_2 *)ti)->first_char == (char)27)) {
+ */
+	if (ti->ti_len && (unsigned)ti->ti_len <= 5 &&
+	    ((struct tcpiphdr_2 *)ti)->first_char == (char)27) {
+		tp->t_flags |= TF_ACKNOW;
+	}
+
+	/*
+	 * Return any desired output.
+	 */
+	if (needoutput || (tp->t_flags & TF_ACKNOW)) {
+		(void) tcp_output(tp);
+	}
+	return;
+
+dropafterack:
+	/*
+	 * Generate an ACK dropping incoming segment if it occupies
+	 * sequence space, where the ACK reflects our state.
+	 */
+	if (tiflags & TH_RST)
+		goto drop;
+	m_freem(m);
+	tp->t_flags |= TF_ACKNOW;
+	(void) tcp_output(tp);
+	return;
+
+dropwithreset:
+	/* reuses m if m!=NULL, m_free() unnecessary */
+	if (tiflags & TH_ACK)
+		tcp_respond(tp, ti, m, (tcp_seq)0, ti->ti_ack, TH_RST);
+	else {
+		if (tiflags & TH_SYN) ti->ti_len++;
+		tcp_respond(tp, ti, m, ti->ti_seq+ti->ti_len, (tcp_seq)0,
+		    TH_RST|TH_ACK);
+	}
+
+	return;
+
+drop:
+	/*
+	 * Drop space held by incoming segment and return.
+	 */
+	m_free(m);
+
+	return;
+}
+
+ /* , ts_present, ts_val, ts_ecr) */
+/*	int *ts_present;
+ *	u_int32_t *ts_val, *ts_ecr;
+ */
+void
+tcp_dooptions(tp, cp, cnt, ti)
+	struct tcpcb *tp;
+	u_char *cp;
+	int cnt;
+	struct tcpiphdr *ti;
+{
+	u_int16_t mss;
+	int opt, optlen;
+
+	DEBUG_CALL("tcp_dooptions");
+	DEBUG_ARGS((dfd," tp = %lx  cnt=%i \n", (long )tp, cnt));
+
+	for (; cnt > 0; cnt -= optlen, cp += optlen) {
+		opt = cp[0];
+		if (opt == TCPOPT_EOL)
+			break;
+		if (opt == TCPOPT_NOP)
+			optlen = 1;
+		else {
+			optlen = cp[1];
+			if (optlen <= 0)
+				break;
+		}
+		switch (opt) {
+
+		default:
+			continue;
+
+		case TCPOPT_MAXSEG:
+			if (optlen != TCPOLEN_MAXSEG)
+				continue;
+			if (!(ti->ti_flags & TH_SYN))
+				continue;
+			memcpy((char *) &mss, (char *) cp + 2, sizeof(mss));
+			NTOHS(mss);
+			(void) tcp_mss(tp, mss);	/* sets t_maxseg */
+			break;
+
+/*		case TCPOPT_WINDOW:
+ *			if (optlen != TCPOLEN_WINDOW)
+ *				continue;
+ *			if (!(ti->ti_flags & TH_SYN))
+ *				continue;
+ *			tp->t_flags |= TF_RCVD_SCALE;
+ *			tp->requested_s_scale = min(cp[2], TCP_MAX_WINSHIFT);
+ *			break;
+ */
+/*		case TCPOPT_TIMESTAMP:
+ *			if (optlen != TCPOLEN_TIMESTAMP)
+ *				continue;
+ *			*ts_present = 1;
+ *			memcpy((char *) ts_val, (char *)cp + 2, sizeof(*ts_val));
+ *			NTOHL(*ts_val);
+ *			memcpy((char *) ts_ecr, (char *)cp + 6, sizeof(*ts_ecr));
+ *			NTOHL(*ts_ecr);
+ *
+ */			/* 
+ *			 * A timestamp received in a SYN makes
+ *			 * it ok to send timestamp requests and replies.
+ *			 */
+/*			if (ti->ti_flags & TH_SYN) {
+ *				tp->t_flags |= TF_RCVD_TSTMP;
+ *				tp->ts_recent = *ts_val;
+ *				tp->ts_recent_age = tcp_now;
+ *			}
+ */			break;
+		}
+	}
+}
+
+
+/*
+ * Pull out of band byte out of a segment so
+ * it doesn't appear in the user's data queue.
+ * It is still reflected in the segment length for
+ * sequencing purposes.
+ */
+
+#ifdef notdef
+
+void
+tcp_pulloutofband(so, ti, m)
+	struct socket *so;
+	struct tcpiphdr *ti;
+	register struct mbuf *m;
+{
+	int cnt = ti->ti_urp - 1;
+	
+	while (cnt >= 0) {
+		if (m->m_len > cnt) {
+			char *cp = mtod(m, caddr_t) + cnt;
+			struct tcpcb *tp = sototcpcb(so);
+
+			tp->t_iobc = *cp;
+			tp->t_oobflags |= TCPOOB_HAVEDATA;
+			memcpy(sp, cp+1, (unsigned)(m->m_len - cnt - 1));
+			m->m_len--;
+			return;
+		}
+		cnt -= m->m_len;
+		m = m->m_next; /* XXX WRONG! Fix it! */
+		if (m == 0)
+			break;
+	}
+	panic("tcp_pulloutofband");
+}
+
+#endif /* notdef */
+
+/*
+ * Collect new round-trip time estimate
+ * and update averages and current timeout.
+ */
+
+void
+tcp_xmit_timer(tp, rtt)
+	register struct tcpcb *tp;
+	int rtt;
+{
+	register short delta;
+
+	DEBUG_CALL("tcp_xmit_timer");
+	DEBUG_ARG("tp = %lx", (long)tp);
+	DEBUG_ARG("rtt = %d", rtt);
+	
+	tcpstat.tcps_rttupdated++;
+	if (tp->t_srtt != 0) {
+		/*
+		 * srtt is stored as fixed point with 3 bits after the
+		 * binary point (i.e., scaled by 8).  The following magic
+		 * is equivalent to the smoothing algorithm in rfc793 with
+		 * an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed
+		 * point).  Adjust rtt to origin 0.
+		 */
+		delta = rtt - 1 - (tp->t_srtt >> TCP_RTT_SHIFT);
+		if ((tp->t_srtt += delta) <= 0)
+			tp->t_srtt = 1;
+		/*
+		 * We accumulate a smoothed rtt variance (actually, a
+		 * smoothed mean difference), then set the retransmit
+		 * timer to smoothed rtt + 4 times the smoothed variance.
+		 * rttvar is stored as fixed point with 2 bits after the
+		 * binary point (scaled by 4).  The following is
+		 * equivalent to rfc793 smoothing with an alpha of .75
+		 * (rttvar = rttvar*3/4 + |delta| / 4).  This replaces
+		 * rfc793's wired-in beta.
+		 */
+		if (delta < 0)
+			delta = -delta;
+		delta -= (tp->t_rttvar >> TCP_RTTVAR_SHIFT);
+		if ((tp->t_rttvar += delta) <= 0)
+			tp->t_rttvar = 1;
+	} else {
+		/* 
+		 * No rtt measurement yet - use the unsmoothed rtt.
+		 * Set the variance to half the rtt (so our first
+		 * retransmit happens at 3*rtt).
+		 */
+		tp->t_srtt = rtt << TCP_RTT_SHIFT;
+		tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
+	}
+	tp->t_rtt = 0;
+	tp->t_rxtshift = 0;
+
+	/*
+	 * the retransmit should happen at rtt + 4 * rttvar.
+	 * Because of the way we do the smoothing, srtt and rttvar
+	 * will each average +1/2 tick of bias.  When we compute
+	 * the retransmit timer, we want 1/2 tick of rounding and
+	 * 1 extra tick because of +-1/2 tick uncertainty in the
+	 * firing of the timer.  The bias will give us exactly the
+	 * 1.5 tick we need.  But, because the bias is
+	 * statistical, we have to test that we don't drop below
+	 * the minimum feasible timer (which is 2 ticks).
+	 */
+	TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
+	    (short)tp->t_rttmin, TCPTV_REXMTMAX); /* XXX */
+	
+	/*
+	 * We received an ack for a packet that wasn't retransmitted;
+	 * it is probably safe to discard any error indications we've
+	 * received recently.  This isn't quite right, but close enough
+	 * for now (a route might have failed after we sent a segment,
+	 * and the return path might not be symmetrical).
+	 */
+	tp->t_softerror = 0;
+}
+
+/*
+ * Determine a reasonable value for maxseg size.
+ * If the route is known, check route for mtu.
+ * If none, use an mss that can be handled on the outgoing
+ * interface without forcing IP to fragment; if bigger than
+ * an mbuf cluster (MCLBYTES), round down to nearest multiple of MCLBYTES
+ * to utilize large mbufs.  If no route is found, route has no mtu,
+ * or the destination isn't local, use a default, hopefully conservative
+ * size (usually 512 or the default IP max size, but no more than the mtu
+ * of the interface), as we can't discover anything about intervening
+ * gateways or networks.  We also initialize the congestion/slow start
+ * window to be a single segment if the destination isn't local.
+ * While looking at the routing entry, we also initialize other path-dependent
+ * parameters from pre-set or cached values in the routing entry.
+ */
+
+int
+tcp_mss(tp, offer)
+        register struct tcpcb *tp;
+        u_int offer;
+{
+	struct socket *so = tp->t_socket;
+	int mss;
+	
+	DEBUG_CALL("tcp_mss");
+	DEBUG_ARG("tp = %lx", (long)tp);
+	DEBUG_ARG("offer = %d", offer);
+	
+	mss = min(if_mtu, if_mru) - sizeof(struct tcpiphdr);
+	if (offer)
+		mss = min(mss, offer);
+	mss = max(mss, 32);
+	if (mss < tp->t_maxseg || offer != 0)
+	   tp->t_maxseg = mss;
+	
+	tp->snd_cwnd = mss;
+	
+	sbreserve(&so->so_snd, tcp_sndspace+((tcp_sndspace%mss)?(mss-(tcp_sndspace%mss)):0));
+	sbreserve(&so->so_rcv, tcp_rcvspace+((tcp_rcvspace%mss)?(mss-(tcp_rcvspace%mss)):0));
+	
+	DEBUG_MISC((dfd, " returning mss = %d\n", mss));
+	
+	return mss;
+}
diff --git a/slirp/tcp_output.c b/slirp/tcp_output.c
new file mode 100644
index 000000000..0f05dfadc
--- /dev/null
+++ b/slirp/tcp_output.c
@@ -0,0 +1,608 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_output.c	8.3 (Berkeley) 12/30/93
+ * tcp_output.c,v 1.3 1994/09/15 10:36:55 davidg Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+
+#define max(x,y) ((x) > (y) ? (x) : (y))
+#define min(x,y) ((x) < (y) ? (x) : (y))
+
+/*
+ * Since this is only used in "stats socket", we give meaning
+ * names instead of the REAL names
+ */
+char *tcpstates[] = {
+/*	"CLOSED",       "LISTEN",       "SYN_SENT",     "SYN_RCVD", */
+	"REDIRECT",	"LISTEN",	"SYN_SENT",     "SYN_RCVD",
+	"ESTABLISHED",  "CLOSE_WAIT",   "FIN_WAIT_1",   "CLOSING",
+	"LAST_ACK",     "FIN_WAIT_2",   "TIME_WAIT",
+};
+
+u_char  tcp_outflags[TCP_NSTATES] = {
+	TH_RST|TH_ACK, 0,      TH_SYN,        TH_SYN|TH_ACK,
+	TH_ACK,        TH_ACK, TH_FIN|TH_ACK, TH_FIN|TH_ACK, 
+	TH_FIN|TH_ACK, TH_ACK, TH_ACK,
+};
+
+
+#define MAX_TCPOPTLEN	32	/* max # bytes that go in options */
+
+/*
+ * Tcp output routine: figure out what should be sent and send it.
+ */
+int
+tcp_output(tp)
+	register struct tcpcb *tp;
+{
+	register struct socket *so = tp->t_socket;
+	register long len, win;
+	int off, flags, error;
+	register struct mbuf *m;
+	register struct tcpiphdr *ti;
+	u_char opt[MAX_TCPOPTLEN];
+	unsigned optlen, hdrlen;
+	int idle, sendalot;
+	
+	DEBUG_CALL("tcp_output");
+	DEBUG_ARG("tp = %lx", (long )tp);
+	
+	/*
+	 * Determine length of data that should be transmitted,
+	 * and flags that will be used.
+	 * If there is some data or critical controls (SYN, RST)
+	 * to send, then transmit; otherwise, investigate further.
+	 */
+	idle = (tp->snd_max == tp->snd_una);
+	if (idle && tp->t_idle >= tp->t_rxtcur)
+		/*
+		 * We have been idle for "a while" and no acks are
+		 * expected to clock out any data we send --
+		 * slow start to get ack "clock" running again.
+		 */
+		tp->snd_cwnd = tp->t_maxseg;
+again:
+	sendalot = 0;
+	off = tp->snd_nxt - tp->snd_una;
+	win = min(tp->snd_wnd, tp->snd_cwnd);
+
+	flags = tcp_outflags[tp->t_state];
+	
+	DEBUG_MISC((dfd, " --- tcp_output flags = 0x%x\n",flags));
+	
+	/*
+	 * If in persist timeout with window of 0, send 1 byte.
+	 * Otherwise, if window is small but nonzero
+	 * and timer expired, we will send what we can
+	 * and go to transmit state.
+	 */
+	if (tp->t_force) {
+		if (win == 0) {
+			/*
+			 * If we still have some data to send, then
+			 * clear the FIN bit.  Usually this would
+			 * happen below when it realizes that we
+			 * aren't sending all the data.  However,
+			 * if we have exactly 1 byte of unset data,
+			 * then it won't clear the FIN bit below,
+			 * and if we are in persist state, we wind
+			 * up sending the packet without recording
+			 * that we sent the FIN bit.
+			 *
+			 * We can't just blindly clear the FIN bit,
+			 * because if we don't have any more data
+			 * to send then the probe will be the FIN
+			 * itself.
+			 */
+			if (off < so->so_snd.sb_cc)
+				flags &= ~TH_FIN;
+			win = 1;
+		} else {
+			tp->t_timer[TCPT_PERSIST] = 0;
+			tp->t_rxtshift = 0;
+		}
+	}
+
+	len = min(so->so_snd.sb_cc, win) - off;
+
+	if (len < 0) {
+		/*
+		 * If FIN has been sent but not acked,
+		 * but we haven't been called to retransmit,
+		 * len will be -1.  Otherwise, window shrank
+		 * after we sent into it.  If window shrank to 0,
+		 * cancel pending retransmit and pull snd_nxt
+		 * back to (closed) window.  We will enter persist
+		 * state below.  If the window didn't close completely,
+		 * just wait for an ACK.
+		 */
+		len = 0;
+		if (win == 0) {
+			tp->t_timer[TCPT_REXMT] = 0;
+			tp->snd_nxt = tp->snd_una;
+		}
+	}
+	
+	if (len > tp->t_maxseg) {
+		len = tp->t_maxseg;
+		sendalot = 1;
+	}
+	if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
+		flags &= ~TH_FIN;
+
+	win = sbspace(&so->so_rcv);
+
+	/*
+	 * Sender silly window avoidance.  If connection is idle
+	 * and can send all data, a maximum segment,
+	 * at least a maximum default-size segment do it,
+	 * or are forced, do it; otherwise don't bother.
+	 * If peer's buffer is tiny, then send
+	 * when window is at least half open.
+	 * If retransmitting (possibly after persist timer forced us
+	 * to send into a small window), then must resend.
+	 */
+	if (len) {
+		if (len == tp->t_maxseg)
+			goto send;
+		if ((1 || idle || tp->t_flags & TF_NODELAY) &&
+		    len + off >= so->so_snd.sb_cc)
+			goto send;
+		if (tp->t_force)
+			goto send;
+		if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0)
+			goto send;
+		if (SEQ_LT(tp->snd_nxt, tp->snd_max))
+			goto send;
+	}
+
+	/*
+	 * Compare available window to amount of window
+	 * known to peer (as advertised window less
+	 * next expected input).  If the difference is at least two
+	 * max size segments, or at least 50% of the maximum possible
+	 * window, then want to send a window update to peer.
+	 */
+	if (win > 0) {
+		/* 
+		 * "adv" is the amount we can increase the window,
+		 * taking into account that we are limited by
+		 * TCP_MAXWIN << tp->rcv_scale.
+		 */
+		long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) -
+			(tp->rcv_adv - tp->rcv_nxt);
+
+		if (adv >= (long) (2 * tp->t_maxseg))
+			goto send;
+		if (2 * adv >= (long) so->so_rcv.sb_datalen)
+			goto send;
+	}
+
+	/*
+	 * Send if we owe peer an ACK.
+	 */
+	if (tp->t_flags & TF_ACKNOW)
+		goto send;
+	if (flags & (TH_SYN|TH_RST))
+		goto send;
+	if (SEQ_GT(tp->snd_up, tp->snd_una))
+		goto send;
+	/*
+	 * If our state indicates that FIN should be sent
+	 * and we have not yet done so, or we're retransmitting the FIN,
+	 * then we need to send.
+	 */
+	if (flags & TH_FIN &&
+	    ((tp->t_flags & TF_SENTFIN) == 0 || tp->snd_nxt == tp->snd_una))
+		goto send;
+
+	/*
+	 * TCP window updates are not reliable, rather a polling protocol
+	 * using ``persist'' packets is used to insure receipt of window
+	 * updates.  The three ``states'' for the output side are:
+	 *	idle			not doing retransmits or persists
+	 *	persisting		to move a small or zero window
+	 *	(re)transmitting	and thereby not persisting
+	 *
+	 * tp->t_timer[TCPT_PERSIST]
+	 *	is set when we are in persist state.
+	 * tp->t_force
+	 *	is set when we are called to send a persist packet.
+	 * tp->t_timer[TCPT_REXMT]
+	 *	is set when we are retransmitting
+	 * The output side is idle when both timers are zero.
+	 *
+	 * If send window is too small, there is data to transmit, and no
+	 * retransmit or persist is pending, then go to persist state.
+	 * If nothing happens soon, send when timer expires:
+	 * if window is nonzero, transmit what we can,
+	 * otherwise force out a byte.
+	 */
+	if (so->so_snd.sb_cc && tp->t_timer[TCPT_REXMT] == 0 &&
+	    tp->t_timer[TCPT_PERSIST] == 0) {
+		tp->t_rxtshift = 0;
+		tcp_setpersist(tp);
+	}
+
+	/*
+	 * No reason to send a segment, just return.
+	 */
+	tcpstat.tcps_didnuttin++;
+	
+	return (0);
+
+send:
+	/*
+	 * Before ESTABLISHED, force sending of initial options
+	 * unless TCP set not to do any options.
+	 * NOTE: we assume that the IP/TCP header plus TCP options
+	 * always fit in a single mbuf, leaving room for a maximum
+	 * link header, i.e.
+	 *	max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MHLEN
+	 */
+	optlen = 0;
+	hdrlen = sizeof (struct tcpiphdr);
+	if (flags & TH_SYN) {
+		tp->snd_nxt = tp->iss;
+		if ((tp->t_flags & TF_NOOPT) == 0) {
+			u_int16_t mss;
+
+			opt[0] = TCPOPT_MAXSEG;
+			opt[1] = 4;
+			mss = htons((u_int16_t) tcp_mss(tp, 0));
+			memcpy((caddr_t)(opt + 2), (caddr_t)&mss, sizeof(mss));
+			optlen = 4;
+
+/*			if ((tp->t_flags & TF_REQ_SCALE) &&
+ *			    ((flags & TH_ACK) == 0 ||
+ *			    (tp->t_flags & TF_RCVD_SCALE))) {
+ *				*((u_int32_t *) (opt + optlen)) = htonl(
+ *					TCPOPT_NOP << 24 |
+ *					TCPOPT_WINDOW << 16 |
+ *					TCPOLEN_WINDOW << 8 |
+ *					tp->request_r_scale);
+ *				optlen += 4;
+ *			}
+ */
+		}
+ 	}
+ 
+ 	/*
+	 * Send a timestamp and echo-reply if this is a SYN and our side 
+	 * wants to use timestamps (TF_REQ_TSTMP is set) or both our side
+	 * and our peer have sent timestamps in our SYN's.
+ 	 */
+/* 	if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
+ *	     (flags & TH_RST) == 0 &&
+ *	    ((flags & (TH_SYN|TH_ACK)) == TH_SYN ||
+ *	     (tp->t_flags & TF_RCVD_TSTMP))) {
+ *		u_int32_t *lp = (u_int32_t *)(opt + optlen);
+ *
+ *		/ * Form timestamp option as shown in appendix A of RFC 1323. *  /
+ *		*lp++ = htonl(TCPOPT_TSTAMP_HDR);
+ *		*lp++ = htonl(tcp_now);
+ *		*lp   = htonl(tp->ts_recent);
+ *		optlen += TCPOLEN_TSTAMP_APPA;
+ *	}
+ */
+ 	hdrlen += optlen;
+ 
+	/*
+	 * Adjust data length if insertion of options will
+	 * bump the packet length beyond the t_maxseg length.
+	 */
+	 if (len > tp->t_maxseg - optlen) {
+		len = tp->t_maxseg - optlen;
+		sendalot = 1;
+	 }
+
+	/*
+	 * Grab a header mbuf, attaching a copy of data to
+	 * be transmitted, and initialize the header from
+	 * the template for sends on this connection.
+	 */
+	if (len) {
+		if (tp->t_force && len == 1)
+			tcpstat.tcps_sndprobe++;
+		else if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
+			tcpstat.tcps_sndrexmitpack++;
+			tcpstat.tcps_sndrexmitbyte += len;
+		} else {
+			tcpstat.tcps_sndpack++;
+			tcpstat.tcps_sndbyte += len;
+		}
+
+		m = m_get();
+		if (m == NULL) {
+/*			error = ENOBUFS; */
+			error = 1;
+			goto out;
+		}
+		m->m_data += if_maxlinkhdr;
+		m->m_len = hdrlen;
+		
+		/* 
+		 * This will always succeed, since we make sure our mbufs
+		 * are big enough to hold one MSS packet + header + ... etc.
+		 */
+/*		if (len <= MHLEN - hdrlen - max_linkhdr) { */
+
+			sbcopy(&so->so_snd, off, (int) len, mtod(m, caddr_t) + hdrlen);
+			m->m_len += len;
+
+/*		} else {
+ *			m->m_next = m_copy(so->so_snd.sb_mb, off, (int) len);
+ *			if (m->m_next == 0)
+ *				len = 0;
+ *		}
+ */
+		/*
+		 * If we're sending everything we've got, set PUSH.
+		 * (This will keep happy those implementations which only
+		 * give data to the user when a buffer fills or
+		 * a PUSH comes in.)
+		 */
+		if (off + len == so->so_snd.sb_cc)
+			flags |= TH_PUSH;
+	} else {
+		if (tp->t_flags & TF_ACKNOW)
+			tcpstat.tcps_sndacks++;
+		else if (flags & (TH_SYN|TH_FIN|TH_RST))
+			tcpstat.tcps_sndctrl++;
+		else if (SEQ_GT(tp->snd_up, tp->snd_una))
+			tcpstat.tcps_sndurg++;
+		else
+			tcpstat.tcps_sndwinup++;
+
+		m = m_get();
+		if (m == NULL) {
+/*			error = ENOBUFS; */
+			error = 1;
+			goto out;
+		}
+		m->m_data += if_maxlinkhdr;
+		m->m_len = hdrlen;
+	}
+
+	ti = mtod(m, struct tcpiphdr *);
+	
+	memcpy((caddr_t)ti, &tp->t_template, sizeof (struct tcpiphdr));
+
+	/*
+	 * Fill in fields, remembering maximum advertised
+	 * window for use in delaying messages about window sizes.
+	 * If resending a FIN, be sure not to use a new sequence number.
+	 */
+	if (flags & TH_FIN && tp->t_flags & TF_SENTFIN && 
+	    tp->snd_nxt == tp->snd_max)
+		tp->snd_nxt--;
+	/*
+	 * If we are doing retransmissions, then snd_nxt will
+	 * not reflect the first unsent octet.  For ACK only
+	 * packets, we do not want the sequence number of the
+	 * retransmitted packet, we want the sequence number
+	 * of the next unsent octet.  So, if there is no data
+	 * (and no SYN or FIN), use snd_max instead of snd_nxt
+	 * when filling in ti_seq.  But if we are in persist
+	 * state, snd_max might reflect one byte beyond the
+	 * right edge of the window, so use snd_nxt in that
+	 * case, since we know we aren't doing a retransmission.
+	 * (retransmit and persist are mutually exclusive...)
+	 */
+	if (len || (flags & (TH_SYN|TH_FIN)) || tp->t_timer[TCPT_PERSIST])
+		ti->ti_seq = htonl(tp->snd_nxt);
+	else
+		ti->ti_seq = htonl(tp->snd_max);
+	ti->ti_ack = htonl(tp->rcv_nxt);
+	if (optlen) {
+		memcpy((caddr_t)(ti + 1), (caddr_t)opt, optlen);
+		ti->ti_off = (sizeof (struct tcphdr) + optlen) >> 2;
+	}
+	ti->ti_flags = flags;
+	/*
+	 * Calculate receive window.  Don't shrink window,
+	 * but avoid silly window syndrome.
+	 */
+	if (win < (long)(so->so_rcv.sb_datalen / 4) && win < (long)tp->t_maxseg)
+		win = 0;
+	if (win > (long)TCP_MAXWIN << tp->rcv_scale)
+		win = (long)TCP_MAXWIN << tp->rcv_scale;
+	if (win < (long)(tp->rcv_adv - tp->rcv_nxt))
+		win = (long)(tp->rcv_adv - tp->rcv_nxt);
+	ti->ti_win = htons((u_int16_t) (win>>tp->rcv_scale));
+	
+	if (SEQ_GT(tp->snd_up, tp->snd_una)) {
+		ti->ti_urp = htons((u_int16_t)(tp->snd_up - ntohl(ti->ti_seq)));
+#ifdef notdef		
+	if (SEQ_GT(tp->snd_up, tp->snd_nxt)) {
+		ti->ti_urp = htons((u_int16_t)(tp->snd_up - tp->snd_nxt));
+#endif
+		ti->ti_flags |= TH_URG;
+	} else
+		/*
+		 * If no urgent pointer to send, then we pull
+		 * the urgent pointer to the left edge of the send window
+		 * so that it doesn't drift into the send window on sequence
+		 * number wraparound.
+		 */
+		tp->snd_up = tp->snd_una;		/* drag it along */
+
+	/*
+	 * Put TCP length in extended header, and then
+	 * checksum extended header and data.
+	 */
+	if (len + optlen)
+		ti->ti_len = htons((u_int16_t)(sizeof (struct tcphdr) +
+		    optlen + len));
+	ti->ti_sum = cksum(m, (int)(hdrlen + len));
+
+	/*
+	 * In transmit state, time the transmission and arrange for
+	 * the retransmit.  In persist state, just set snd_max.
+	 */
+	if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0) {
+		tcp_seq startseq = tp->snd_nxt;
+
+		/*
+		 * Advance snd_nxt over sequence space of this segment.
+		 */
+		if (flags & (TH_SYN|TH_FIN)) {
+			if (flags & TH_SYN)
+				tp->snd_nxt++;
+			if (flags & TH_FIN) {
+				tp->snd_nxt++;
+				tp->t_flags |= TF_SENTFIN;
+			}
+		}
+		tp->snd_nxt += len;
+		if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
+			tp->snd_max = tp->snd_nxt;
+			/*
+			 * Time this transmission if not a retransmission and
+			 * not currently timing anything.
+			 */
+			if (tp->t_rtt == 0) {
+				tp->t_rtt = 1;
+				tp->t_rtseq = startseq;
+				tcpstat.tcps_segstimed++;
+			}
+		}
+
+		/*
+		 * Set retransmit timer if not currently set,
+		 * and not doing an ack or a keep-alive probe.
+		 * Initial value for retransmit timer is smoothed
+		 * round-trip time + 2 * round-trip time variance.
+		 * Initialize shift counter which is used for backoff
+		 * of retransmit time.
+		 */
+		if (tp->t_timer[TCPT_REXMT] == 0 &&
+		    tp->snd_nxt != tp->snd_una) {
+			tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+			if (tp->t_timer[TCPT_PERSIST]) {
+				tp->t_timer[TCPT_PERSIST] = 0;
+				tp->t_rxtshift = 0;
+			}
+		}
+	} else
+		if (SEQ_GT(tp->snd_nxt + len, tp->snd_max))
+			tp->snd_max = tp->snd_nxt + len;
+
+	/*
+	 * Fill in IP length and desired time to live and
+	 * send to IP level.  There should be a better way
+	 * to handle ttl and tos; we could keep them in
+	 * the template, but need a way to checksum without them.
+	 */
+	m->m_len = hdrlen + len; /* XXX Needed? m_len should be correct */
+	
+    {
+	    
+	((struct ip *)ti)->ip_len = m->m_len;
+
+	((struct ip *)ti)->ip_ttl = ip_defttl;
+	((struct ip *)ti)->ip_tos = so->so_iptos;
+	    
+/* #if BSD >= 43 */
+	/* Don't do IP options... */
+/*	error = ip_output(m, tp->t_inpcb->inp_options, &tp->t_inpcb->inp_route,
+ *	    so->so_options & SO_DONTROUTE, 0);
+ */
+	error = ip_output(so, m);
+
+/* #else
+ *	error = ip_output(m, (struct mbuf *)0, &tp->t_inpcb->inp_route, 
+ *	    so->so_options & SO_DONTROUTE);
+ * #endif
+ */
+    }
+	if (error) {
+out:
+/*		if (error == ENOBUFS) {
+ *			tcp_quench(tp->t_inpcb, 0);
+ *			return (0);
+ *		}
+ */
+/*		if ((error == EHOSTUNREACH || error == ENETDOWN)
+ *		    && TCPS_HAVERCVDSYN(tp->t_state)) {
+ *			tp->t_softerror = error;
+ *			return (0);
+ *		}
+ */
+		return (error);
+	}
+	tcpstat.tcps_sndtotal++;
+
+	/*
+	 * Data sent (as far as we can tell).
+	 * If this advertises a larger window than any other segment,
+	 * then remember the size of the advertised window.
+	 * Any pending ACK has now been sent.
+	 */
+	if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv))
+		tp->rcv_adv = tp->rcv_nxt + win;
+	tp->last_ack_sent = tp->rcv_nxt;
+	tp->t_flags &= ~(TF_ACKNOW|TF_DELACK);
+	if (sendalot)
+		goto again;
+
+	return (0);
+}
+
+void
+tcp_setpersist(tp)
+	register struct tcpcb *tp;
+{
+    int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1;
+
+/*	if (tp->t_timer[TCPT_REXMT])
+ *		panic("tcp_output REXMT");
+ */
+	/*
+	 * Start/restart persistence timer.
+	 */
+	TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
+	    t * tcp_backoff[tp->t_rxtshift],
+	    TCPTV_PERSMIN, TCPTV_PERSMAX);
+	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
+		tp->t_rxtshift++;
+}
diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c
new file mode 100644
index 000000000..bf8a2026f
--- /dev/null
+++ b/slirp/tcp_subr.c
@@ -0,0 +1,1325 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_subr.c	8.1 (Berkeley) 6/10/93
+ * tcp_subr.c,v 1.5 1994/10/08 22:39:58 phk Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#define WANT_SYS_IOCTL_H
+#include <slirp.h>
+
+/* patchable/settable parameters for tcp */
+int 	tcp_mssdflt = TCP_MSS;
+int 	tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
+int	tcp_do_rfc1323 = 0;	/* Don't do rfc1323 performance enhancements */
+int	tcp_rcvspace;	/* You may want to change this */
+int	tcp_sndspace;	/* Keep small if you have an error prone link */
+
+/*
+ * Tcp initialization
+ */
+void
+tcp_init()
+{
+	tcp_iss = 1;		/* wrong */
+	tcb.so_next = tcb.so_prev = &tcb;
+	
+	/* tcp_rcvspace = our Window we advertise to the remote */
+	tcp_rcvspace = TCP_RCVSPACE;
+	tcp_sndspace = TCP_SNDSPACE;
+	
+	/* Make sure tcp_sndspace is at least 2*MSS */
+	if (tcp_sndspace < 2*(min(if_mtu, if_mru) - sizeof(struct tcpiphdr)))
+		tcp_sndspace = 2*(min(if_mtu, if_mru) - sizeof(struct tcpiphdr));
+}
+
+/*
+ * Create template to be used to send tcp packets on a connection.
+ * Call after host entry created, fills
+ * in a skeletal tcp/ip header, minimizing the amount of work
+ * necessary when the connection is used.
+ */
+/* struct tcpiphdr * */
+void
+tcp_template(tp)
+	struct tcpcb *tp;
+{
+	struct socket *so = tp->t_socket;
+	register struct tcpiphdr *n = &tp->t_template;
+
+	n->ti_next = n->ti_prev = 0;
+	n->ti_x1 = 0;
+	n->ti_pr = IPPROTO_TCP;
+	n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
+	n->ti_src = so->so_faddr;
+	n->ti_dst = so->so_laddr;
+	n->ti_sport = so->so_fport;
+	n->ti_dport = so->so_lport;
+	
+	n->ti_seq = 0;
+	n->ti_ack = 0;
+	n->ti_x2 = 0;
+	n->ti_off = 5;
+	n->ti_flags = 0;
+	n->ti_win = 0;
+	n->ti_sum = 0;
+	n->ti_urp = 0;
+}
+
+/*
+ * Send a single message to the TCP at address specified by
+ * the given TCP/IP header.  If m == 0, then we make a copy
+ * of the tcpiphdr at ti and send directly to the addressed host.
+ * This is used to force keep alive messages out using the TCP
+ * template for a connection tp->t_template.  If flags are given
+ * then we send a message back to the TCP which originated the
+ * segment ti, and discard the mbuf containing it and any other
+ * attached mbufs.
+ *
+ * In any case the ack and sequence number of the transmitted
+ * segment are as specified by the parameters.
+ */
+void
+tcp_respond(tp, ti, m, ack, seq, flags)
+	struct tcpcb *tp;
+	register struct tcpiphdr *ti;
+	register struct mbuf *m;
+	tcp_seq ack, seq;
+	int flags;
+{
+	register int tlen;
+	int win = 0;
+
+	DEBUG_CALL("tcp_respond");
+	DEBUG_ARG("tp = %lx", (long)tp);
+	DEBUG_ARG("ti = %lx", (long)ti);
+	DEBUG_ARG("m = %lx", (long)m);
+	DEBUG_ARG("ack = %u", ack);
+	DEBUG_ARG("seq = %u", seq);
+	DEBUG_ARG("flags = %x", flags);
+	
+	if (tp)
+		win = sbspace(&tp->t_socket->so_rcv);
+	if (m == 0) {
+		if ((m = m_get()) == NULL)
+			return;
+#ifdef TCP_COMPAT_42
+		tlen = 1;
+#else
+		tlen = 0;
+#endif
+		m->m_data += if_maxlinkhdr;
+		*mtod(m, struct tcpiphdr *) = *ti;
+		ti = mtod(m, struct tcpiphdr *);
+		flags = TH_ACK;
+	} else {
+		/* 
+		 * ti points into m so the next line is just making
+		 * the mbuf point to ti
+		 */
+		m->m_data = (caddr_t)ti;
+		
+		m->m_len = sizeof (struct tcpiphdr);
+		tlen = 0;
+#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
+		xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_int32_t);
+		xchg(ti->ti_dport, ti->ti_sport, u_int16_t);
+#undef xchg
+	}
+	ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen));
+	tlen += sizeof (struct tcpiphdr);
+	m->m_len = tlen;
+
+	ti->ti_next = ti->ti_prev = 0;
+	ti->ti_x1 = 0;
+	ti->ti_seq = htonl(seq);
+	ti->ti_ack = htonl(ack);
+	ti->ti_x2 = 0;
+	ti->ti_off = sizeof (struct tcphdr) >> 2;
+	ti->ti_flags = flags;
+	if (tp)
+		ti->ti_win = htons((u_int16_t) (win >> tp->rcv_scale));
+	else
+		ti->ti_win = htons((u_int16_t)win);
+	ti->ti_urp = 0;
+	ti->ti_sum = 0;
+	ti->ti_sum = cksum(m, tlen);
+	((struct ip *)ti)->ip_len = tlen;
+
+	if(flags & TH_RST) 
+	  ((struct ip *)ti)->ip_ttl = MAXTTL;
+	else 
+	  ((struct ip *)ti)->ip_ttl = ip_defttl;
+	
+	(void) ip_output((struct socket *)0, m);
+}
+
+/*
+ * Create a new TCP control block, making an
+ * empty reassembly queue and hooking it to the argument
+ * protocol control block.
+ */
+struct tcpcb *
+tcp_newtcpcb(so)
+	struct socket *so;
+{
+	register struct tcpcb *tp;
+	
+	tp = (struct tcpcb *)malloc(sizeof(*tp));
+	if (tp == NULL)
+		return ((struct tcpcb *)0);
+	
+	memset((char *) tp, 0, sizeof(struct tcpcb));
+	tp->seg_next = tp->seg_prev = (tcpiphdrp_32)tp;
+	tp->t_maxseg = tcp_mssdflt;
+	
+	tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0;
+	tp->t_socket = so;
+	
+	/*
+	 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
+	 * rtt estimate.  Set rttvar so that srtt + 2 * rttvar gives
+	 * reasonable initial retransmit time.
+	 */
+	tp->t_srtt = TCPTV_SRTTBASE;
+	tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 2;
+	tp->t_rttmin = TCPTV_MIN;
+
+	TCPT_RANGESET(tp->t_rxtcur, 
+	    ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
+	    TCPTV_MIN, TCPTV_REXMTMAX);
+
+	tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
+	tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
+	tp->t_state = TCPS_CLOSED;
+	
+	so->so_tcpcb = tp;
+
+	return (tp);
+}
+
+/*
+ * Drop a TCP connection, reporting
+ * the specified error.  If connection is synchronized,
+ * then send a RST to peer.
+ */
+struct tcpcb *tcp_drop(struct tcpcb *tp, int errno) 
+{
+/* tcp_drop(tp, errno)
+	register struct tcpcb *tp;
+	int errno;
+{
+*/
+
+	DEBUG_CALL("tcp_drop");
+	DEBUG_ARG("tp = %lx", (long)tp);
+	DEBUG_ARG("errno = %d", errno);
+	
+	if (TCPS_HAVERCVDSYN(tp->t_state)) {
+		tp->t_state = TCPS_CLOSED;
+		(void) tcp_output(tp);
+		tcpstat.tcps_drops++;
+	} else
+		tcpstat.tcps_conndrops++;
+/*	if (errno == ETIMEDOUT && tp->t_softerror)
+ *		errno = tp->t_softerror;
+ */
+/*	so->so_error = errno; */
+	return (tcp_close(tp));
+}
+
+/*
+ * Close a TCP control block:
+ *	discard all space held by the tcp
+ *	discard internet protocol block
+ *	wake up any sleepers
+ */
+struct tcpcb *
+tcp_close(tp)
+	register struct tcpcb *tp;
+{
+	register struct tcpiphdr *t;
+	struct socket *so = tp->t_socket;
+	register struct mbuf *m;
+
+	DEBUG_CALL("tcp_close");
+	DEBUG_ARG("tp = %lx", (long )tp);
+	
+	/* free the reassembly queue, if any */
+	t = (struct tcpiphdr *) tp->seg_next;
+	while (t != (struct tcpiphdr *)tp) {
+		t = (struct tcpiphdr *)t->ti_next;
+		m = (struct mbuf *) REASS_MBUF((struct tcpiphdr *)t->ti_prev);
+		remque_32((struct tcpiphdr *) t->ti_prev);
+		m_freem(m);
+	}
+	/* It's static */
+/*	if (tp->t_template)
+ *		(void) m_free(dtom(tp->t_template));
+ */
+/*	free(tp, M_PCB);  */
+	free(tp);
+	so->so_tcpcb = 0;
+	soisfdisconnected(so);
+	/* clobber input socket cache if we're closing the cached connection */
+	if (so == tcp_last_so)
+		tcp_last_so = &tcb;
+	close(so->s);
+	sbfree(&so->so_rcv);
+	sbfree(&so->so_snd);
+	sofree(so);
+	tcpstat.tcps_closed++;
+	return ((struct tcpcb *)0);
+}
+
+void
+tcp_drain()
+{
+	/* XXX */
+}
+
+/*
+ * When a source quench is received, close congestion window
+ * to one segment.  We will gradually open it again as we proceed.
+ */
+
+#ifdef notdef
+
+void
+tcp_quench(i, errno)
+
+	int errno;
+{
+	struct tcpcb *tp = intotcpcb(inp);
+
+	if (tp)
+		tp->snd_cwnd = tp->t_maxseg;
+}
+
+#endif /* notdef */
+
+/*
+ * TCP protocol interface to socket abstraction.
+ */
+
+/*
+ * User issued close, and wish to trail through shutdown states:
+ * if never received SYN, just forget it.  If got a SYN from peer,
+ * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
+ * If already got a FIN from peer, then almost done; go to LAST_ACK
+ * state.  In all other cases, have already sent FIN to peer (e.g.
+ * after PRU_SHUTDOWN), and just have to play tedious game waiting
+ * for peer to send FIN or not respond to keep-alives, etc.
+ * We can let the user exit from the close as soon as the FIN is acked.
+ */
+void
+tcp_sockclosed(tp)
+	struct tcpcb *tp;
+{
+
+	DEBUG_CALL("tcp_sockclosed");
+	DEBUG_ARG("tp = %lx", (long)tp);
+	
+	switch (tp->t_state) {
+
+	case TCPS_CLOSED:
+	case TCPS_LISTEN:
+	case TCPS_SYN_SENT:
+		tp->t_state = TCPS_CLOSED;
+		tp = tcp_close(tp);
+		break;
+
+	case TCPS_SYN_RECEIVED:
+	case TCPS_ESTABLISHED:
+		tp->t_state = TCPS_FIN_WAIT_1;
+		break;
+
+	case TCPS_CLOSE_WAIT:
+		tp->t_state = TCPS_LAST_ACK;
+		break;
+	}
+/*	soisfdisconnecting(tp->t_socket); */
+	if (tp && tp->t_state >= TCPS_FIN_WAIT_2)
+		soisfdisconnected(tp->t_socket);
+	if (tp)
+		tcp_output(tp);
+}
+
+/* 
+ * Connect to a host on the Internet
+ * Called by tcp_input
+ * Only do a connect, the tcp fields will be set in tcp_input
+ * return 0 if there's a result of the connect,
+ * else return -1 means we're still connecting
+ * The return value is almost always -1 since the socket is
+ * nonblocking.  Connect returns after the SYN is sent, and does 
+ * not wait for ACK+SYN.
+ */
+int tcp_fconnect(so)
+     struct socket *so;
+{
+  int ret=0;
+  
+  DEBUG_CALL("tcp_fconnect");
+  DEBUG_ARG("so = %lx", (long )so);
+
+  if( (ret=so->s=socket(AF_INET,SOCK_STREAM,0)) >= 0) {
+    int opt, s=so->s;
+    struct sockaddr_in addr;
+
+    fd_nonblock(s);
+    opt = 1;
+    setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(opt ));
+    opt = 1;
+    setsockopt(s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(opt ));
+    
+    addr.sin_family = AF_INET;
+    if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) {
+      /* It's an alias */
+      switch(ntohl(so->so_faddr.s_addr) & 0xff) {
+      case CTL_DNS:
+	addr.sin_addr = dns_addr;
+	break;
+      case CTL_ALIAS:
+      default:
+	addr.sin_addr = loopback_addr;
+	break;
+      }
+    } else
+      addr.sin_addr = so->so_faddr;
+    addr.sin_port = so->so_fport;
+    
+    DEBUG_MISC((dfd, " connect()ing, addr.sin_port=%d, "
+		"addr.sin_addr.s_addr=%.16s\n", 
+		ntohs(addr.sin_port), inet_ntoa(addr.sin_addr)));
+    /* We don't care what port we get */
+    ret = connect(s,(struct sockaddr *)&addr,sizeof (addr));
+    
+    /*
+     * If it's not in progress, it failed, so we just return 0,
+     * without clearing SS_NOFDREF
+     */
+    soisfconnecting(so);
+  }
+
+  return(ret);
+}
+
+/*
+ * Accept the socket and connect to the local-host
+ * 
+ * We have a problem. The correct thing to do would be
+ * to first connect to the local-host, and only if the
+ * connection is accepted, then do an accept() here.
+ * But, a) we need to know who's trying to connect 
+ * to the socket to be able to SYN the local-host, and
+ * b) we are already connected to the foreign host by
+ * the time it gets to accept(), so... We simply accept
+ * here and SYN the local-host.
+ */ 
+void
+tcp_connect(inso)
+	struct socket *inso;
+{
+	struct socket *so;
+	struct sockaddr_in addr;
+	int addrlen = sizeof(struct sockaddr_in);
+	struct tcpcb *tp;
+	int s, opt;
+
+	DEBUG_CALL("tcp_connect");
+	DEBUG_ARG("inso = %lx", (long)inso);
+	
+	/*
+	 * If it's an SS_ACCEPTONCE socket, no need to socreate()
+	 * another socket, just use the accept() socket.
+	 */
+	if (inso->so_state & SS_FACCEPTONCE) {
+		/* FACCEPTONCE already have a tcpcb */
+		so = inso;
+	} else {
+		if ((so = socreate()) == NULL) {
+			/* If it failed, get rid of the pending connection */
+			close(accept(inso->s,(struct sockaddr *)&addr,&addrlen));
+			return;
+		}
+		if (tcp_attach(so) < 0) {
+			free(so); /* NOT sofree */
+			return;
+		}
+		so->so_laddr = inso->so_laddr;
+		so->so_lport = inso->so_lport;
+	}
+	
+	(void) tcp_mss(sototcpcb(so), 0);
+
+	if ((s = accept(inso->s,(struct sockaddr *)&addr,&addrlen)) < 0) {
+		tcp_close(sototcpcb(so)); /* This will sofree() as well */
+		return;
+	}
+	fd_nonblock(s);
+	opt = 1;
+	setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
+	opt = 1;
+	setsockopt(s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int));
+	
+	so->so_fport = addr.sin_port;
+	so->so_faddr = addr.sin_addr;
+	/* Translate connections from localhost to the real hostname */
+	if (so->so_faddr.s_addr == 0 || so->so_faddr.s_addr == loopback_addr.s_addr)
+	   so->so_faddr = our_addr;
+	
+	/* Close the accept() socket, set right state */
+	if (inso->so_state & SS_FACCEPTONCE) {
+		close(so->s); /* If we only accept once, close the accept() socket */
+		so->so_state = SS_NOFDREF; /* Don't select it yet, even though we have an FD */
+					   /* if it's not FACCEPTONCE, it's already NOFDREF */
+	}
+	so->s = s;
+	
+	so->so_iptos = tcp_tos(so);
+	tp = sototcpcb(so);
+
+	tcp_template(tp);
+	
+	/* Compute window scaling to request.  */
+/*	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
+ *		(TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
+ *		tp->request_r_scale++;
+ */
+
+/*	soisconnecting(so); */ /* NOFDREF used instead */
+	tcpstat.tcps_connattempt++;
+	
+	tp->t_state = TCPS_SYN_SENT;
+	tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
+	tp->iss = tcp_iss; 
+	tcp_iss += TCP_ISSINCR/2;
+	tcp_sendseqinit(tp);
+	tcp_output(tp);
+}
+
+/*
+ * Attach a TCPCB to a socket.
+ */
+int
+tcp_attach(so)
+	struct socket *so;
+{
+	if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
+	   return -1;
+	
+	insque(so, &tcb);
+
+	return 0;
+}
+
+/*
+ * Set the socket's type of service field
+ */
+struct tos_t tcptos[] = {
+	  {0, 20, IPTOS_THROUGHPUT, 0},	/* ftp data */
+	  {21, 21, IPTOS_LOWDELAY,  EMU_FTP},	/* ftp control */
+	  {0, 23, IPTOS_LOWDELAY, 0},	/* telnet */
+	  {0, 80, IPTOS_THROUGHPUT, 0},	/* WWW */
+	  {0, 513, IPTOS_LOWDELAY, EMU_RLOGIN|EMU_NOCONNECT},	/* rlogin */
+	  {0, 514, IPTOS_LOWDELAY, EMU_RSH|EMU_NOCONNECT},	/* shell */
+	  {0, 544, IPTOS_LOWDELAY, EMU_KSH},		/* kshell */
+	  {0, 543, IPTOS_LOWDELAY, 0},	/* klogin */
+	  {0, 6667, IPTOS_THROUGHPUT, EMU_IRC},	/* IRC */
+	  {0, 6668, IPTOS_THROUGHPUT, EMU_IRC},	/* IRC undernet */
+	  {0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
+	  {0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
+	  {0, 0, 0, 0}
+};
+
+struct emu_t *tcpemu = 0;
+		
+/*
+ * Return TOS according to the above table
+ */
+u_int8_t
+tcp_tos(so)
+	struct socket *so;
+{
+	int i = 0;
+	struct emu_t *emup;
+	
+	while(tcptos[i].tos) {
+		if ((tcptos[i].fport && (ntohs(so->so_fport) == tcptos[i].fport)) ||
+		    (tcptos[i].lport && (ntohs(so->so_lport) == tcptos[i].lport))) {
+			so->so_emu = tcptos[i].emu;
+			return tcptos[i].tos;
+		}
+		i++;
+	}
+	
+	/* Nope, lets see if there's a user-added one */
+	for (emup = tcpemu; emup; emup = emup->next) {
+		if ((emup->fport && (ntohs(so->so_fport) == emup->fport)) ||
+		    (emup->lport && (ntohs(so->so_lport) == emup->lport))) {
+			so->so_emu = emup->emu;
+			return emup->tos;
+		}
+	}
+	
+	return 0;
+}
+
+int do_echo = -1;
+
+/*
+ * Emulate programs that try and connect to us
+ * This includes ftp (the data connection is
+ * initiated by the server) and IRC (DCC CHAT and
+ * DCC SEND) for now
+ * 
+ * NOTE: It's possible to crash SLiRP by sending it
+ * unstandard strings to emulate... if this is a problem,
+ * more checks are needed here
+ *
+ * XXX Assumes the whole command came in one packet
+ *					    
+ * XXX Some ftp clients will have their TOS set to
+ * LOWDELAY and so Nagel will kick in.  Because of this,
+ * we'll get the first letter, followed by the rest, so
+ * we simply scan for ORT instead of PORT...
+ * DCC doesn't have this problem because there's other stuff
+ * in the packet before the DCC command.
+ * 
+ * Return 1 if the mbuf m is still valid and should be 
+ * sbappend()ed
+ * 
+ * NOTE: if you return 0 you MUST m_free() the mbuf!
+ */
+int
+tcp_emu(so, m)
+	struct socket *so;
+	struct mbuf *m;
+{
+	u_int n1, n2, n3, n4, n5, n6;
+	char buff[256];
+	u_int32_t laddr;
+	u_int lport;
+	char *bptr;
+	
+	DEBUG_CALL("tcp_emu");
+	DEBUG_ARG("so = %lx", (long)so);
+	DEBUG_ARG("m = %lx", (long)m);
+	
+	switch(so->so_emu) {
+		int x, i;
+		
+	 case EMU_IDENT:
+		/*
+		 * Identification protocol as per rfc-1413
+		 */
+		
+		{
+			struct socket *tmpso;
+			struct sockaddr_in addr;
+			int addrlen = sizeof(struct sockaddr_in);
+			struct sbuf *so_rcv = &so->so_rcv;
+			
+			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
+			so_rcv->sb_wptr += m->m_len;
+			so_rcv->sb_rptr += m->m_len;
+			m->m_data[m->m_len] = 0; /* NULL terminate */
+			if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
+				if (sscanf(so_rcv->sb_data, "%d%*[ ,]%d", &n1, &n2) == 2) {
+					HTONS(n1);
+					HTONS(n2);
+					/* n2 is the one on our host */
+					for (tmpso = tcb.so_next; tmpso != &tcb; tmpso = tmpso->so_next) {
+						if (tmpso->so_laddr.s_addr == so->so_laddr.s_addr &&
+						    tmpso->so_lport == n2 &&
+						    tmpso->so_faddr.s_addr == so->so_faddr.s_addr &&
+						    tmpso->so_fport == n1) {
+							if (getsockname(tmpso->s,
+								(struct sockaddr *)&addr, &addrlen) == 0)
+							   n2 = ntohs(addr.sin_port);
+							break;
+						}
+					}
+				}
+				so_rcv->sb_cc = sprintf(so_rcv->sb_data, "%d,%d\r\n", n1, n2);
+				so_rcv->sb_rptr = so_rcv->sb_data;
+				so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
+			}
+			m_free(m);
+			return 0;
+		}
+		
+#if 0
+	 case EMU_RLOGIN:
+		/*
+		 * Rlogin emulation
+		 * First we accumulate all the initial option negotiation,
+		 * then fork_exec() rlogin according to the  options
+		 */
+		{
+			int i, i2, n;
+			char *ptr;
+			char args[100];
+			char term[100];
+			struct sbuf *so_snd = &so->so_snd;
+			struct sbuf *so_rcv = &so->so_rcv;
+			
+			/* First check if they have a priveladged port, or too much data has arrived */
+			if (ntohs(so->so_lport) > 1023 || ntohs(so->so_lport) < 512 ||
+			    (m->m_len + so_rcv->sb_wptr) > (so_rcv->sb_data + so_rcv->sb_datalen)) {
+				memcpy(so_snd->sb_wptr, "Permission denied\n", 18);
+				so_snd->sb_wptr += 18;
+				so_snd->sb_cc += 18;
+				tcp_sockclosed(sototcpcb(so));
+				m_free(m);
+				return 0;
+			}
+			
+			/* Append the current data */
+			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
+			so_rcv->sb_wptr += m->m_len;
+			so_rcv->sb_rptr += m->m_len;
+			m_free(m);
+			
+			/*
+			 * Check if we have all the initial options,
+			 * and build argument list to rlogin while we're here
+			 */
+			n = 0;
+			ptr = so_rcv->sb_data;
+			args[0] = 0;
+			term[0] = 0;
+			while (ptr < so_rcv->sb_wptr) {
+				if (*ptr++ == 0) {
+					n++;
+					if (n == 2) {
+						sprintf(args, "rlogin -l %s %s",
+							ptr, inet_ntoa(so->so_faddr));
+					} else if (n == 3) {
+						i2 = so_rcv->sb_wptr - ptr;
+						for (i = 0; i < i2; i++) {
+							if (ptr[i] == '/') {
+								ptr[i] = 0;
+#ifdef HAVE_SETENV
+								sprintf(term, "%s", ptr);
+#else
+								sprintf(term, "TERM=%s", ptr);
+#endif
+								ptr[i] = '/';
+								break;
+							}
+						}
+					}
+				}
+			}
+			
+			if (n != 4)
+			   return 0;
+			
+			/* We have it, set our term variable and fork_exec() */
+#ifdef HAVE_SETENV
+			setenv("TERM", term, 1);
+#else
+			putenv(term);
+#endif
+			fork_exec(so, args, 2);
+			term[0] = 0;
+			so->so_emu = 0;
+			
+			/* And finally, send the client a 0 character */
+			so_snd->sb_wptr[0] = 0;
+			so_snd->sb_wptr++;
+			so_snd->sb_cc++;
+			
+			return 0;
+		}
+		
+	 case EMU_RSH:
+		/*
+		 * rsh emulation
+		 * First we accumulate all the initial option negotiation,
+		 * then rsh_exec() rsh according to the  options
+		 */
+		{
+			int  n;
+			char *ptr;
+			char *user;
+			char *args;
+			struct sbuf *so_snd = &so->so_snd;
+			struct sbuf *so_rcv = &so->so_rcv;
+			
+			/* First check if they have a priveladged port, or too much data has arrived */
+			if (ntohs(so->so_lport) > 1023 || ntohs(so->so_lport) < 512 ||
+			    (m->m_len + so_rcv->sb_wptr) > (so_rcv->sb_data + so_rcv->sb_datalen)) {
+				memcpy(so_snd->sb_wptr, "Permission denied\n", 18);
+				so_snd->sb_wptr += 18;
+				so_snd->sb_cc += 18;
+				tcp_sockclosed(sototcpcb(so));
+				m_free(m);
+				return 0;
+			}
+			
+			/* Append the current data */
+			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
+			so_rcv->sb_wptr += m->m_len;
+			so_rcv->sb_rptr += m->m_len;
+			m_free(m);
+			
+			/*
+			 * Check if we have all the initial options,
+			 * and build argument list to rlogin while we're here
+			 */
+			n = 0;
+			ptr = so_rcv->sb_data;
+			user="";
+			args="";
+			if (so->extra==NULL) {
+				struct socket *ns;
+				struct tcpcb* tp;
+				int port=atoi(ptr);
+				if (port <= 0) return 0;
+                if (port > 1023 || port < 512) {
+                  memcpy(so_snd->sb_wptr, "Permission denied\n", 18);
+                  so_snd->sb_wptr += 18;
+                  so_snd->sb_cc += 18;
+                  tcp_sockclosed(sototcpcb(so));
+                  return 0;
+                }
+				if ((ns=socreate()) == NULL)
+                  return 0;
+				if (tcp_attach(ns)<0) {
+                  free(ns);
+                  return 0;
+				}
+
+				ns->so_laddr=so->so_laddr;
+				ns->so_lport=htons(port);
+
+				(void) tcp_mss(sototcpcb(ns), 0);
+
+				ns->so_faddr=so->so_faddr;
+				ns->so_fport=htons(IPPORT_RESERVED-1); /* Use a fake port. */
+
+				if (ns->so_faddr.s_addr == 0 || 
+					ns->so_faddr.s_addr == loopback_addr.s_addr)
+                  ns->so_faddr = our_addr;
+
+				ns->so_iptos = tcp_tos(ns);
+				tp = sototcpcb(ns);
+                
+				tcp_template(tp);
+                
+				/* Compute window scaling to request.  */
+				/*	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
+				 *		(TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
+				 *		tp->request_r_scale++;
+				 */
+
+                /*soisfconnecting(ns);*/
+
+				tcpstat.tcps_connattempt++;
+					
+				tp->t_state = TCPS_SYN_SENT;
+				tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
+				tp->iss = tcp_iss; 
+				tcp_iss += TCP_ISSINCR/2;
+				tcp_sendseqinit(tp);
+				tcp_output(tp);
+				so->extra=ns;
+			}
+			while (ptr < so_rcv->sb_wptr) {
+              if (*ptr++ == 0) {
+                n++;
+                if (n == 2) {
+                  user=ptr;
+                } else if (n == 3) {
+                  args=ptr;
+                }
+              }
+			}
+			
+			if (n != 4)
+              return 0;
+			
+			rsh_exec(so,so->extra, user, inet_ntoa(so->so_faddr), args);
+			so->so_emu = 0;
+			so->extra=NULL;
+			
+			/* And finally, send the client a 0 character */
+			so_snd->sb_wptr[0] = 0;
+			so_snd->sb_wptr++;
+			so_snd->sb_cc++;
+			
+			return 0;
+		}
+
+	 case EMU_CTL:
+		{
+			int num;
+			struct sbuf *so_snd = &so->so_snd;
+			struct sbuf *so_rcv = &so->so_rcv;
+			
+			/*
+			 * If there is binary data here, we save it in so->so_m
+			 */
+			if (!so->so_m) {
+			  int rxlen;
+			  char *rxdata;
+			  rxdata=mtod(m, char *);
+			  for (rxlen=m->m_len; rxlen; rxlen--) {
+			    if (*rxdata++ & 0x80) {
+			      so->so_m = m;
+			      return 0;
+			    }
+			  }
+			} /* if(so->so_m==NULL) */
+			
+			/*
+			 * Append the line
+			 */
+			sbappendsb(so_rcv, m);
+			
+			/* To avoid going over the edge of the buffer, we reset it */
+			if (so_snd->sb_cc == 0)
+			   so_snd->sb_wptr = so_snd->sb_rptr = so_snd->sb_data;
+			
+			/*
+			 * A bit of a hack:
+			 * If the first packet we get here is 1 byte long, then it
+			 * was done in telnet character mode, therefore we must echo
+			 * the characters as they come.  Otherwise, we echo nothing,
+			 * because in linemode, the line is already echoed
+			 * XXX two or more control connections won't work
+			 */
+			if (do_echo == -1) {
+				if (m->m_len == 1) do_echo = 1;
+				else do_echo = 0;
+			}
+			if (do_echo) {
+			  sbappendsb(so_snd, m);
+			  m_free(m);
+			  tcp_output(sototcpcb(so)); /* XXX */
+			} else
+			  m_free(m);
+			
+			num = 0;
+			while (num < so->so_rcv.sb_cc) {
+				if (*(so->so_rcv.sb_rptr + num) == '\n' ||
+				    *(so->so_rcv.sb_rptr + num) == '\r') {
+					int n;
+					
+					*(so_rcv->sb_rptr + num) = 0;
+					if (ctl_password && !ctl_password_ok) {
+						/* Need a password */
+						if (sscanf(so_rcv->sb_rptr, "pass %256s", buff) == 1) {
+							if (strcmp(buff, ctl_password) == 0) {
+								ctl_password_ok = 1;
+								n = sprintf(so_snd->sb_wptr,
+									    "Password OK.\r\n");
+								goto do_prompt;
+							}
+						}
+						n = sprintf(so_snd->sb_wptr,
+					 "Error: Password required, log on with \"pass PASSWORD\"\r\n");
+						goto do_prompt;
+					}
+					cfg_quitting = 0;
+					n = do_config(so_rcv->sb_rptr, so, PRN_SPRINTF);
+					if (!cfg_quitting) {
+						/* Register the printed data */
+do_prompt:
+						so_snd->sb_cc += n;
+						so_snd->sb_wptr += n;
+						/* Add prompt */
+						n = sprintf(so_snd->sb_wptr, "Slirp> ");
+						so_snd->sb_cc += n;
+						so_snd->sb_wptr += n;
+					}
+					/* Drop so_rcv data */
+					so_rcv->sb_cc = 0;
+					so_rcv->sb_wptr = so_rcv->sb_rptr = so_rcv->sb_data;
+					tcp_output(sototcpcb(so)); /* Send the reply */
+				}
+				num++;
+			}
+			return 0;
+		}
+#endif		
+        case EMU_FTP: /* ftp */
+		*(m->m_data+m->m_len) = 0; /* NULL terminate for strstr */
+		if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
+			/*
+			 * Need to emulate the PORT command
+			 */			
+			x = sscanf(bptr, "ORT %d,%d,%d,%d,%d,%d\r\n%256[^\177]", 
+				   &n1, &n2, &n3, &n4, &n5, &n6, buff);
+			if (x < 6)
+			   return 1;
+			
+			laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
+			lport = htons((n5 << 8) | (n6));
+			
+			if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
+			   return 1;
+			
+			n6 = ntohs(so->so_fport);
+			
+			n5 = (n6 >> 8) & 0xff;
+			n6 &= 0xff;
+			
+			laddr = ntohl(so->so_faddr.s_addr);
+			
+			n1 = ((laddr >> 24) & 0xff);
+			n2 = ((laddr >> 16) & 0xff);
+			n3 = ((laddr >> 8)  & 0xff);
+			n4 =  (laddr & 0xff);
+			
+			m->m_len = bptr - m->m_data; /* Adjust length */
+			m->m_len += sprintf(bptr,"ORT %d,%d,%d,%d,%d,%d\r\n%s", 
+					    n1, n2, n3, n4, n5, n6, x==7?buff:"");
+			return 1;
+		} else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
+			/*
+			 * Need to emulate the PASV response
+			 */
+			x = sscanf(bptr, "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%256[^\177]",
+				   &n1, &n2, &n3, &n4, &n5, &n6, buff);
+			if (x < 6)
+			   return 1;
+			
+			laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
+			lport = htons((n5 << 8) | (n6));
+			
+			if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
+			   return 1;
+			
+			n6 = ntohs(so->so_fport);
+			
+			n5 = (n6 >> 8) & 0xff;
+			n6 &= 0xff;
+			
+			laddr = ntohl(so->so_faddr.s_addr);
+			
+			n1 = ((laddr >> 24) & 0xff);
+			n2 = ((laddr >> 16) & 0xff);
+			n3 = ((laddr >> 8)  & 0xff);
+			n4 =  (laddr & 0xff);
+			
+			m->m_len = bptr - m->m_data; /* Adjust length */
+			m->m_len += sprintf(bptr,"27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
+					    n1, n2, n3, n4, n5, n6, x==7?buff:"");
+			
+			return 1;
+		}
+		
+		return 1;
+				   
+	 case EMU_KSH:
+		/*
+		 * The kshell (Kerberos rsh) and shell services both pass
+		 * a local port port number to carry signals to the server
+		 * and stderr to the client.  It is passed at the beginning
+		 * of the connection as a NUL-terminated decimal ASCII string.
+		 */
+		so->so_emu = 0;
+		for (lport = 0, i = 0; i < m->m_len-1; ++i) {
+			if (m->m_data[i] < '0' || m->m_data[i] > '9')
+				return 1;       /* invalid number */
+			lport *= 10;
+			lport += m->m_data[i] - '0';
+		}
+		if (m->m_data[m->m_len-1] == '\0' && lport != 0 &&
+		    (so = solisten(0, so->so_laddr.s_addr, htons(lport), SS_FACCEPTONCE)) != NULL)
+			m->m_len = sprintf(m->m_data, "%d", ntohs(so->so_fport))+1;
+		return 1;
+		
+	 case EMU_IRC:
+		/*
+		 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
+		 */
+		*(m->m_data+m->m_len) = 0; /* NULL terminate the string for strstr */
+		if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
+			 return 1;
+		
+		/* The %256s is for the broken mIRC */
+		if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
+			if ((so = solisten(0, htonl(laddr), htons(lport), SS_FACCEPTONCE)) == NULL)
+				return 1;
+			
+			m->m_len = bptr - m->m_data; /* Adjust length */
+			m->m_len += sprintf(bptr, "DCC CHAT chat %lu %u%c\n",
+			     (unsigned long)ntohl(so->so_faddr.s_addr),
+			     ntohs(so->so_fport), 1);
+		} else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
+			if ((so = solisten(0, htonl(laddr), htons(lport), SS_FACCEPTONCE)) == NULL)
+				return 1;
+			
+			m->m_len = bptr - m->m_data; /* Adjust length */
+			m->m_len += sprintf(bptr, "DCC SEND %s %lu %u %u%c\n", 
+			      buff, (unsigned long)ntohl(so->so_faddr.s_addr),
+			      ntohs(so->so_fport), n1, 1);
+		} else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
+			if ((so = solisten(0, htonl(laddr), htons(lport), SS_FACCEPTONCE)) == NULL)
+				return 1;
+			
+			m->m_len = bptr - m->m_data; /* Adjust length */
+			m->m_len += sprintf(bptr, "DCC MOVE %s %lu %u %u%c\n",
+			      buff, (unsigned long)ntohl(so->so_faddr.s_addr),
+			      ntohs(so->so_fport), n1, 1);
+		}
+		return 1;
+
+	 case EMU_REALAUDIO:
+                /* 
+		 * RealAudio emulation - JP. We must try to parse the incoming
+		 * data and try to find the two characters that contain the
+		 * port number. Then we redirect an udp port and replace the
+		 * number with the real port we got.
+		 *
+		 * The 1.0 beta versions of the player are not supported
+		 * any more.
+		 * 
+		 * A typical packet for player version 1.0 (release version):
+		 *        
+		 * 0000:50 4E 41 00 05 
+		 * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 .....×..gælÜc..P
+		 * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
+		 * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
+		 * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
+		 *         
+		 * Now the port number 0x1BD7 is found at offset 0x04 of the
+		 * Now the port number 0x1BD7 is found at offset 0x04 of the
+		 * second packet. This time we received five bytes first and
+		 * then the rest. You never know how many bytes you get.
+		 *
+		 * A typical packet for player version 2.0 (beta):
+		 *        
+		 * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA...........Á.
+		 * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .guxõc..Win2.0.0
+		 * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
+		 * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
+		 * 0040:65 2E 72 61 79 53 00 00 06 36 42                e.rayS...6B
+		 *        
+		 * Port number 0x1BC1 is found at offset 0x0d.
+		 *      
+		 * This is just a horrible switch statement. Variable ra tells
+		 * us where we're going.
+		 */
+		
+		bptr = m->m_data;
+		while (bptr < m->m_data + m->m_len) {
+			u_short p;
+			static int ra = 0;
+			char ra_tbl[4]; 
+			
+			ra_tbl[0] = 0x50;
+			ra_tbl[1] = 0x4e;
+			ra_tbl[2] = 0x41;
+			ra_tbl[3] = 0;
+			
+			switch (ra) {
+			 case 0:
+			 case 2:
+			 case 3:
+				if (*bptr++ != ra_tbl[ra]) {
+					ra = 0;
+					continue;
+				}
+				break;
+				
+			 case 1:
+				/*
+				 * We may get 0x50 several times, ignore them
+				 */
+				if (*bptr == 0x50) {
+					ra = 1;
+					bptr++;
+					continue;
+				} else if (*bptr++ != ra_tbl[ra]) {
+					ra = 0;
+					continue;
+				}
+				break;
+				
+			 case 4: 
+				/* 
+				 * skip version number
+				 */
+				bptr++;
+				break;
+				
+			 case 5: 
+				/*
+				 * The difference between versions 1.0 and
+				 * 2.0 is here. For future versions of
+				 * the player this may need to be modified.
+				 */
+				if (*(bptr + 1) == 0x02)
+				   bptr += 8;
+				else
+				   bptr += 4;
+				break;                          
+				
+			 case 6:
+				/* This is the field containing the port
+				 * number that RA-player is listening to.
+				 */
+				lport = (((u_char*)bptr)[0] << 8) 
+				+ ((u_char *)bptr)[1];
+				if (lport < 6970)      
+				   lport += 256;   /* don't know why */
+				if (lport < 6970 || lport > 7170)
+				   return 1;       /* failed */
+				
+				/* try to get udp port between 6970 - 7170 */
+				for (p = 6970; p < 7071; p++) {
+					if (udp_listen( htons(p),
+						       so->so_laddr.s_addr,
+						       htons(lport),
+						       SS_FACCEPTONCE)) {
+						break;
+					}
+				}
+				if (p == 7071)
+				   p = 0;
+				*(u_char *)bptr++ = (p >> 8) & 0xff;
+				*(u_char *)bptr++ = p & 0xff;
+				ra = 0; 
+				return 1;   /* port redirected, we're done */
+				break;  
+				
+			 default:
+				ra = 0;                         
+			}
+			ra++;
+		}
+		return 1;                                
+		
+	 default:
+		/* Ooops, not emulated, won't call tcp_emu again */
+		so->so_emu = 0;
+		return 1;
+	}
+}
+
+/*
+ * Do misc. config of SLiRP while its running.
+ * Return 0 if this connections is to be closed, 1 otherwise,
+ * return 2 if this is a command-line connection
+ */
+int
+tcp_ctl(so)
+	struct socket *so;
+{
+#if 0
+	struct sbuf *sb = &so->so_snd;
+	int command;
+ 	struct ex_list *ex_ptr;
+	int do_pty;
+	struct socket *tmpso;
+	
+	DEBUG_CALL("tcp_ctl");
+	DEBUG_ARG("so = %lx", (long )so);
+	
+	/*
+	 * Check if they're authorised
+	 */
+	if (ctl_addr.s_addr && (ctl_addr.s_addr == -1 || (so->so_laddr.s_addr != ctl_addr.s_addr))) {
+		sb->sb_cc = sprintf(sb->sb_wptr,"Error: Permission denied.\r\n");
+		sb->sb_wptr += sb->sb_cc;
+		return 0;
+	}
+	
+	command = (ntohl(so->so_faddr.s_addr) & 0xff);
+	
+	switch(command) {
+	default: /* Check for exec's */
+		
+		/*
+		 * Check if it's pty_exec
+		 */
+		for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
+			if (ex_ptr->ex_fport == so->so_fport &&
+			    command == ex_ptr->ex_addr) {
+				do_pty = ex_ptr->ex_pty;
+				goto do_exec;
+			}
+		}
+		
+		/*
+		 * Nothing bound..
+		 */
+		/* tcp_fconnect(so); */
+		
+		/* FALLTHROUGH */
+	case CTL_ALIAS:
+	  sb->sb_cc = sprintf(sb->sb_wptr,
+			      "Error: No application configured.\r\n");
+	  sb->sb_wptr += sb->sb_cc;
+	  return(0);
+
+	do_exec:
+		DEBUG_MISC((dfd, " executing %s \n",ex_ptr->ex_exec));
+		return(fork_exec(so, ex_ptr->ex_exec, do_pty));
+		
+	case CTL_CMD:
+	   for (tmpso = tcb.so_next; tmpso != &tcb; tmpso = tmpso->so_next) {
+	     if (tmpso->so_emu == EMU_CTL && 
+		 !(tmpso->so_tcpcb? 
+		   (tmpso->so_tcpcb->t_state & (TCPS_TIME_WAIT|TCPS_LAST_ACK))
+		   :0)) {
+	       /* Ooops, control connection already active */
+	       sb->sb_cc = sprintf(sb->sb_wptr,"Sorry, already connected.\r\n");
+	       sb->sb_wptr += sb->sb_cc;
+	       return 0;
+	     }
+	   }
+	   so->so_emu = EMU_CTL;
+	   ctl_password_ok = 0;
+	   sb->sb_cc = sprintf(sb->sb_wptr, "Slirp command-line ready (type \"help\" for help).\r\nSlirp> ");
+	   sb->sb_wptr += sb->sb_cc;
+	   do_echo=-1;
+	   return(2);
+	}
+#else
+        return 0;
+#endif
+}
diff --git a/slirp/tcp_timer.c b/slirp/tcp_timer.c
new file mode 100644
index 000000000..166979a3e
--- /dev/null
+++ b/slirp/tcp_timer.c
@@ -0,0 +1,329 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_timer.c	8.1 (Berkeley) 6/10/93
+ * tcp_timer.c,v 1.2 1994/08/02 07:49:10 davidg Exp
+ */
+
+#include <slirp.h>
+
+#define max(x,y) ((x) > (y) ? (x) : (y))
+#define min(x,y) ((x) < (y) ? (x) : (y))
+
+int	tcp_keepidle = TCPTV_KEEP_IDLE;
+int	tcp_keepintvl = TCPTV_KEEPINTVL;
+int	tcp_maxidle;
+int	so_options = DO_KEEPALIVE;
+
+struct   tcpstat tcpstat;        /* tcp statistics */
+u_int32_t        tcp_now;                /* for RFC 1323 timestamps */
+
+/*
+ * Fast timeout routine for processing delayed acks
+ */
+void
+tcp_fasttimo()
+{
+	register struct socket *so;
+	register struct tcpcb *tp;
+
+	DEBUG_CALL("tcp_fasttimo");
+	
+	so = tcb.so_next;
+	if (so)
+	for (; so != &tcb; so = so->so_next)
+		if ((tp = (struct tcpcb *)so->so_tcpcb) &&
+		    (tp->t_flags & TF_DELACK)) {
+			tp->t_flags &= ~TF_DELACK;
+			tp->t_flags |= TF_ACKNOW;
+			tcpstat.tcps_delack++;
+			(void) tcp_output(tp);
+		}
+}
+
+/*
+ * Tcp protocol timeout routine called every 500 ms.
+ * Updates the timers in all active tcb's and
+ * causes finite state machine actions if timers expire.
+ */
+void
+tcp_slowtimo()
+{
+	register struct socket *ip, *ipnxt;
+	register struct tcpcb *tp;
+	register int i;
+
+	DEBUG_CALL("tcp_slowtimo");
+	
+	tcp_maxidle = TCPTV_KEEPCNT * tcp_keepintvl;
+	/*
+	 * Search through tcb's and update active timers.
+	 */
+	ip = tcb.so_next;
+	if (ip == 0)
+	   return;
+	for (; ip != &tcb; ip = ipnxt) {
+		ipnxt = ip->so_next;
+		tp = sototcpcb(ip);
+		if (tp == 0)
+			continue;
+		for (i = 0; i < TCPT_NTIMERS; i++) {
+			if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
+				tcp_timers(tp,i);
+				if (ipnxt->so_prev != ip)
+					goto tpgone;
+			}
+		}
+		tp->t_idle++;
+		if (tp->t_rtt)
+		   tp->t_rtt++;
+tpgone:
+		;
+	}
+	tcp_iss += TCP_ISSINCR/PR_SLOWHZ;		/* increment iss */
+#ifdef TCP_COMPAT_42
+	if ((int)tcp_iss < 0)
+		tcp_iss = 0;				/* XXX */
+#endif
+	tcp_now++;					/* for timestamps */
+}
+
+/*
+ * Cancel all timers for TCP tp.
+ */
+void
+tcp_canceltimers(tp)
+	struct tcpcb *tp;
+{
+	register int i;
+
+	for (i = 0; i < TCPT_NTIMERS; i++)
+		tp->t_timer[i] = 0;
+}
+
+int	tcp_backoff[TCP_MAXRXTSHIFT + 1] =
+   { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
+
+/*
+ * TCP timer processing.
+ */
+struct tcpcb *
+tcp_timers(tp, timer)
+	register struct tcpcb *tp;
+	int timer;
+{
+	register int rexmt;
+	
+	DEBUG_CALL("tcp_timers");
+	
+	switch (timer) {
+
+	/*
+	 * 2 MSL timeout in shutdown went off.  If we're closed but
+	 * still waiting for peer to close and connection has been idle
+	 * too long, or if 2MSL time is up from TIME_WAIT, delete connection
+	 * control block.  Otherwise, check again in a bit.
+	 */
+	case TCPT_2MSL:
+		if (tp->t_state != TCPS_TIME_WAIT &&
+		    tp->t_idle <= tcp_maxidle)
+			tp->t_timer[TCPT_2MSL] = tcp_keepintvl;
+		else
+			tp = tcp_close(tp);
+		break;
+
+	/*
+	 * Retransmission timer went off.  Message has not
+	 * been acked within retransmit interval.  Back off
+	 * to a longer retransmit interval and retransmit one segment.
+	 */
+	case TCPT_REXMT:
+		
+		/*
+		 * XXXXX If a packet has timed out, then remove all the queued
+		 * packets for that session.
+		 */
+		
+		if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
+			/*
+			 * This is a hack to suit our terminal server here at the uni of canberra
+			 * since they have trouble with zeroes... It usually lets them through
+			 * unharmed, but under some conditions, it'll eat the zeros.  If we
+			 * keep retransmitting it, it'll keep eating the zeroes, so we keep
+			 * retransmitting, and eventually the connection dies...
+			 * (this only happens on incoming data)
+			 * 
+			 * So, if we were gonna drop the connection from too many retransmits,
+			 * don't... instead halve the t_maxseg, which might break up the NULLs and
+			 * let them through
+			 * 
+			 * *sigh*
+			 */
+			
+			tp->t_maxseg >>= 1;
+			if (tp->t_maxseg < 32) {
+				/*
+				 * We tried our best, now the connection must die!
+				 */
+				tp->t_rxtshift = TCP_MAXRXTSHIFT;
+				tcpstat.tcps_timeoutdrop++;
+				tp = tcp_drop(tp, tp->t_softerror);
+				/* tp->t_softerror : ETIMEDOUT); */ /* XXX */
+				return (tp); /* XXX */
+			}
+			
+			/*
+			 * Set rxtshift to 6, which is still at the maximum
+			 * backoff time
+			 */
+			tp->t_rxtshift = 6;
+		}
+		tcpstat.tcps_rexmttimeo++;
+		rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
+		TCPT_RANGESET(tp->t_rxtcur, rexmt,
+		    (short)tp->t_rttmin, TCPTV_REXMTMAX); /* XXX */
+		tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+		/*
+		 * If losing, let the lower level know and try for
+		 * a better route.  Also, if we backed off this far,
+		 * our srtt estimate is probably bogus.  Clobber it
+		 * so we'll take the next rtt measurement as our srtt;
+		 * move the current srtt into rttvar to keep the current
+		 * retransmit times until then.
+		 */
+		if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
+/*			in_losing(tp->t_inpcb); */
+			tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
+			tp->t_srtt = 0;
+		}
+		tp->snd_nxt = tp->snd_una;
+		/*
+		 * If timing a segment in this window, stop the timer.
+		 */
+		tp->t_rtt = 0;
+		/*
+		 * Close the congestion window down to one segment
+		 * (we'll open it by one segment for each ack we get).
+		 * Since we probably have a window's worth of unacked
+		 * data accumulated, this "slow start" keeps us from
+		 * dumping all that data as back-to-back packets (which
+		 * might overwhelm an intermediate gateway).
+		 *
+		 * There are two phases to the opening: Initially we
+		 * open by one mss on each ack.  This makes the window
+		 * size increase exponentially with time.  If the
+		 * window is larger than the path can handle, this
+		 * exponential growth results in dropped packet(s)
+		 * almost immediately.  To get more time between 
+		 * drops but still "push" the network to take advantage
+		 * of improving conditions, we switch from exponential
+		 * to linear window opening at some threshold size.
+		 * For a threshold, we use half the current window
+		 * size, truncated to a multiple of the mss.
+		 *
+		 * (the minimum cwnd that will give us exponential
+		 * growth is 2 mss.  We don't allow the threshold
+		 * to go below this.)
+		 */
+		{
+		u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg;
+		if (win < 2)
+			win = 2;
+		tp->snd_cwnd = tp->t_maxseg;
+		tp->snd_ssthresh = win * tp->t_maxseg;
+		tp->t_dupacks = 0;
+		}
+		(void) tcp_output(tp);
+		break;
+
+	/*
+	 * Persistence timer into zero window.
+	 * Force a byte to be output, if possible.
+	 */
+	case TCPT_PERSIST:
+		tcpstat.tcps_persisttimeo++;
+		tcp_setpersist(tp);
+		tp->t_force = 1;
+		(void) tcp_output(tp);
+		tp->t_force = 0;
+		break;
+
+	/*
+	 * Keep-alive timer went off; send something
+	 * or drop connection if idle for too long.
+	 */
+	case TCPT_KEEP:
+		tcpstat.tcps_keeptimeo++;
+		if (tp->t_state < TCPS_ESTABLISHED)
+			goto dropit;
+
+/*		if (tp->t_socket->so_options & SO_KEEPALIVE && */
+		if ((so_options) && tp->t_state <= TCPS_CLOSE_WAIT) {
+		    	if (tp->t_idle >= tcp_keepidle + tcp_maxidle)
+				goto dropit;
+			/*
+			 * Send a packet designed to force a response
+			 * if the peer is up and reachable:
+			 * either an ACK if the connection is still alive,
+			 * or an RST if the peer has closed the connection
+			 * due to timeout or reboot.
+			 * Using sequence number tp->snd_una-1
+			 * causes the transmitted zero-length segment
+			 * to lie outside the receive window;
+			 * by the protocol spec, this requires the
+			 * correspondent TCP to respond.
+			 */
+			tcpstat.tcps_keepprobe++;
+#ifdef TCP_COMPAT_42
+			/*
+			 * The keepalive packet must have nonzero length
+			 * to get a 4.2 host to respond.
+			 */
+			tcp_respond(tp, &tp->t_template, (struct mbuf *)NULL,
+			    tp->rcv_nxt - 1, tp->snd_una - 1, 0);
+#else
+			tcp_respond(tp, &tp->t_template, (struct mbuf *)NULL,
+			    tp->rcv_nxt, tp->snd_una - 1, 0);
+#endif
+			tp->t_timer[TCPT_KEEP] = tcp_keepintvl;
+		} else
+			tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+		break;
+
+	dropit:
+		tcpstat.tcps_keepdrops++;
+		tp = tcp_drop(tp, 0); /* ETIMEDOUT); */
+		break;
+	}
+
+	return (tp);
+}
diff --git a/slirp/tcp_timer.h b/slirp/tcp_timer.h
new file mode 100644
index 000000000..59933bc1b
--- /dev/null
+++ b/slirp/tcp_timer.h
@@ -0,0 +1,142 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_timer.h	8.1 (Berkeley) 6/10/93
+ * tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp
+ */
+
+#ifndef _TCP_TIMER_H_
+#define _TCP_TIMER_H_
+
+/*
+ * Definitions of the TCP timers.  These timers are counted
+ * down PR_SLOWHZ times a second.
+ */
+#define	TCPT_NTIMERS	4
+
+#define	TCPT_REXMT	0		/* retransmit */
+#define	TCPT_PERSIST	1		/* retransmit persistence */
+#define	TCPT_KEEP	2		/* keep alive */
+#define	TCPT_2MSL	3		/* 2*msl quiet time timer */
+
+/*
+ * The TCPT_REXMT timer is used to force retransmissions.
+ * The TCP has the TCPT_REXMT timer set whenever segments
+ * have been sent for which ACKs are expected but not yet
+ * received.  If an ACK is received which advances tp->snd_una,
+ * then the retransmit timer is cleared (if there are no more
+ * outstanding segments) or reset to the base value (if there
+ * are more ACKs expected).  Whenever the retransmit timer goes off,
+ * we retransmit one unacknowledged segment, and do a backoff
+ * on the retransmit timer.
+ *
+ * The TCPT_PERSIST timer is used to keep window size information
+ * flowing even if the window goes shut.  If all previous transmissions
+ * have been acknowledged (so that there are no retransmissions in progress),
+ * and the window is too small to bother sending anything, then we start
+ * the TCPT_PERSIST timer.  When it expires, if the window is nonzero,
+ * we go to transmit state.  Otherwise, at intervals send a single byte
+ * into the peer's window to force him to update our window information.
+ * We do this at most as often as TCPT_PERSMIN time intervals,
+ * but no more frequently than the current estimate of round-trip
+ * packet time.  The TCPT_PERSIST timer is cleared whenever we receive
+ * a window update from the peer.
+ *
+ * The TCPT_KEEP timer is used to keep connections alive.  If an
+ * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
+ * but not yet established, then we drop the connection.  Once the connection
+ * is established, if the connection is idle for TCPTV_KEEP_IDLE time
+ * (and keepalives have been enabled on the socket), we begin to probe
+ * the connection.  We force the peer to send us a segment by sending:
+ *	<SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
+ * This segment is (deliberately) outside the window, and should elicit
+ * an ack segment in response from the peer.  If, despite the TCPT_KEEP
+ * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
+ * amount of time probing, then we drop the connection.
+ */
+
+/*
+ * Time constants.
+ */
+#define TCPTV_MSL       ( 5*PR_SLOWHZ)          /* max seg lifetime (hah!) */
+
+#define	TCPTV_SRTTBASE	0			/* base roundtrip time;
+						   if 0, no idea yet */
+#define	TCPTV_SRTTDFLT	(  3*PR_SLOWHZ)		/* assumed RTT if no info */
+
+#define	TCPTV_PERSMIN	(  5*PR_SLOWHZ)		/* retransmit persistence */
+#define	TCPTV_PERSMAX	( 60*PR_SLOWHZ)		/* maximum persist interval */
+
+#define	TCPTV_KEEP_INIT	( 75*PR_SLOWHZ)		/* initial connect keep alive */
+#define	TCPTV_KEEP_IDLE	(120*60*PR_SLOWHZ)	/* dflt time before probing */
+#define	TCPTV_KEEPINTVL	( 75*PR_SLOWHZ)		/* default probe interval */
+#define	TCPTV_KEEPCNT	8			/* max probes before drop */
+
+#define	TCPTV_MIN	(  1*PR_SLOWHZ)		/* minimum allowable value */
+/* #define	TCPTV_REXMTMAX	( 64*PR_SLOWHZ)	*/	/* max allowable REXMT value */
+#define TCPTV_REXMTMAX  ( 12*PR_SLOWHZ)		/* max allowable REXMT value */
+
+#define	TCP_LINGERTIME	120			/* linger at most 2 minutes */
+
+#define TCP_MAXRXTSHIFT 12                      /* maximum retransmits */
+
+
+#ifdef	TCPTIMERS
+char *tcptimers[] =
+    { "REXMT", "PERSIST", "KEEP", "2MSL" };
+#endif
+
+/*
+ * Force a time value to be in a certain range.
+ */
+#define	TCPT_RANGESET(tv, value, tvmin, tvmax) { \
+	(tv) = (value); \
+	if ((tv) < (tvmin)) \
+		(tv) = (tvmin); \
+	else if ((tv) > (tvmax)) \
+		(tv) = (tvmax); \
+}
+
+extern int tcp_keepidle;		/* time before keepalive probes begin */
+extern int tcp_keepintvl;		/* time between keepalive probes */
+extern int tcp_maxidle;			/* time to drop after starting probes */
+extern int tcp_ttl;			/* time to live for TCP segs */
+extern int tcp_backoff[];
+
+struct tcpcb;
+
+void tcp_fasttimo _P((void));
+void tcp_slowtimo _P((void));
+void tcp_canceltimers _P((struct tcpcb *));
+struct tcpcb * tcp_timers _P((register struct tcpcb *, int));
+
+#endif
diff --git a/slirp/tcp_var.h b/slirp/tcp_var.h
new file mode 100644
index 000000000..0d6cd245e
--- /dev/null
+++ b/slirp/tcp_var.h
@@ -0,0 +1,252 @@
+/*
+ * Copyright (c) 1982, 1986, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp_var.h	8.3 (Berkeley) 4/10/94
+ * tcp_var.h,v 1.3 1994/08/21 05:27:39 paul Exp
+ */
+
+#ifndef _TCP_VAR_H_
+#define _TCP_VAR_H_
+
+#include "tcpip.h"
+#include "tcp_timer.h"
+
+#if SIZEOF_CHAR_P == 4
+ typedef struct tcpiphdr *tcpiphdrp_32;
+#else
+ typedef u_int32_t tcpiphdrp_32;
+#endif
+
+/*
+ * Tcp control block, one per tcp; fields:
+ */
+struct tcpcb {
+	tcpiphdrp_32 seg_next;	/* sequencing queue */
+	tcpiphdrp_32 seg_prev;
+	short	t_state;		/* state of this connection */
+	short	t_timer[TCPT_NTIMERS];	/* tcp timers */
+	short	t_rxtshift;		/* log(2) of rexmt exp. backoff */
+	short	t_rxtcur;		/* current retransmit value */
+	short	t_dupacks;		/* consecutive dup acks recd */
+	u_short	t_maxseg;		/* maximum segment size */
+	char	t_force;		/* 1 if forcing out a byte */
+	u_short	t_flags;
+#define	TF_ACKNOW	0x0001		/* ack peer immediately */
+#define	TF_DELACK	0x0002		/* ack, but try to delay it */
+#define	TF_NODELAY	0x0004		/* don't delay packets to coalesce */
+#define	TF_NOOPT	0x0008		/* don't use tcp options */
+#define	TF_SENTFIN	0x0010		/* have sent FIN */
+#define	TF_REQ_SCALE	0x0020		/* have/will request window scaling */
+#define	TF_RCVD_SCALE	0x0040		/* other side has requested scaling */
+#define	TF_REQ_TSTMP	0x0080		/* have/will request timestamps */
+#define	TF_RCVD_TSTMP	0x0100		/* a timestamp was received in SYN */
+#define	TF_SACK_PERMIT	0x0200		/* other side said I could SACK */
+
+	/* Make it static  for now */
+/*	struct	tcpiphdr *t_template;	/ * skeletal packet for transmit */
+	struct	tcpiphdr t_template;
+
+	struct	socket *t_socket;		/* back pointer to socket */
+/*
+ * The following fields are used as in the protocol specification.
+ * See RFC783, Dec. 1981, page 21.
+ */
+/* send sequence variables */
+	tcp_seq	snd_una;		/* send unacknowledged */
+	tcp_seq	snd_nxt;		/* send next */
+	tcp_seq	snd_up;			/* send urgent pointer */
+	tcp_seq	snd_wl1;		/* window update seg seq number */
+	tcp_seq	snd_wl2;		/* window update seg ack number */
+	tcp_seq	iss;			/* initial send sequence number */
+	u_int32_t snd_wnd;		/* send window */
+/* receive sequence variables */
+	u_int32_t rcv_wnd;		/* receive window */
+	tcp_seq	rcv_nxt;		/* receive next */
+	tcp_seq	rcv_up;			/* receive urgent pointer */
+	tcp_seq	irs;			/* initial receive sequence number */
+/*
+ * Additional variables for this implementation.
+ */
+/* receive variables */
+	tcp_seq	rcv_adv;		/* advertised window */
+/* retransmit variables */
+	tcp_seq	snd_max;		/* highest sequence number sent;
+					 * used to recognize retransmits
+					 */
+/* congestion control (for slow start, source quench, retransmit after loss) */
+	u_int32_t snd_cwnd;		/* congestion-controlled window */
+	u_int32_t snd_ssthresh;		/* snd_cwnd size threshold for
+					 * for slow start exponential to
+					 * linear switch
+					 */
+/*
+ * transmit timing stuff.  See below for scale of srtt and rttvar.
+ * "Variance" is actually smoothed difference.
+ */
+	short	t_idle;			/* inactivity time */
+	short	t_rtt;			/* round trip time */
+	tcp_seq	t_rtseq;		/* sequence number being timed */
+	short	t_srtt;			/* smoothed round-trip time */
+	short	t_rttvar;		/* variance in round-trip time */
+	u_short	t_rttmin;		/* minimum rtt allowed */
+	u_int32_t max_sndwnd;		/* largest window peer has offered */
+
+/* out-of-band data */
+	char	t_oobflags;		/* have some */
+	char	t_iobc;			/* input character */
+#define	TCPOOB_HAVEDATA	0x01
+#define	TCPOOB_HADDATA	0x02
+	short	t_softerror;		/* possible error not yet reported */
+
+/* RFC 1323 variables */
+	u_char	snd_scale;		/* window scaling for send window */
+	u_char	rcv_scale;		/* window scaling for recv window */
+	u_char	request_r_scale;	/* pending window scaling */
+	u_char	requested_s_scale;
+	u_int32_t	ts_recent;		/* timestamp echo data */
+	u_int32_t	ts_recent_age;		/* when last updated */
+	tcp_seq	last_ack_sent;
+
+};
+
+#define	sototcpcb(so)	((so)->so_tcpcb)
+
+/*
+ * The smoothed round-trip time and estimated variance
+ * are stored as fixed point numbers scaled by the values below.
+ * For convenience, these scales are also used in smoothing the average
+ * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
+ * With these scales, srtt has 3 bits to the right of the binary point,
+ * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
+ * binary point, and is smoothed with an ALPHA of 0.75.
+ */
+#define	TCP_RTT_SCALE		8	/* multiplier for srtt; 3 bits frac. */
+#define	TCP_RTT_SHIFT		3	/* shift for srtt; 3 bits frac. */
+#define	TCP_RTTVAR_SCALE	4	/* multiplier for rttvar; 2 bits */
+#define	TCP_RTTVAR_SHIFT	2	/* multiplier for rttvar; 2 bits */
+
+/*
+ * The initial retransmission should happen at rtt + 4 * rttvar.
+ * Because of the way we do the smoothing, srtt and rttvar
+ * will each average +1/2 tick of bias.  When we compute
+ * the retransmit timer, we want 1/2 tick of rounding and
+ * 1 extra tick because of +-1/2 tick uncertainty in the
+ * firing of the timer.  The bias will give us exactly the
+ * 1.5 tick we need.  But, because the bias is
+ * statistical, we have to test that we don't drop below
+ * the minimum feasible timer (which is 2 ticks).
+ * This macro assumes that the value of TCP_RTTVAR_SCALE
+ * is the same as the multiplier for rttvar.
+ */
+#define	TCP_REXMTVAL(tp) \
+	(((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
+
+/* XXX
+ * We want to avoid doing m_pullup on incoming packets but that
+ * means avoiding dtom on the tcp reassembly code.  That in turn means
+ * keeping an mbuf pointer in the reassembly queue (since we might
+ * have a cluster).  As a quick hack, the source & destination
+ * port numbers (which are no longer needed once we've located the
+ * tcpcb) are overlayed with an mbuf pointer.
+ */
+#if SIZEOF_CHAR_P == 4
+typedef struct mbuf *mbufp_32;
+#else
+typedef u_int32_t mbufp_32;
+#endif
+#define REASS_MBUF(ti) (*(mbufp_32 *)&((ti)->ti_t))
+
+/*
+ * TCP statistics.
+ * Many of these should be kept per connection,
+ * but that's inconvenient at the moment.
+ */
+struct tcpstat {
+	u_long	tcps_connattempt;	/* connections initiated */
+	u_long	tcps_accepts;		/* connections accepted */
+	u_long	tcps_connects;		/* connections established */
+	u_long	tcps_drops;		/* connections dropped */
+	u_long	tcps_conndrops;		/* embryonic connections dropped */
+	u_long	tcps_closed;		/* conn. closed (includes drops) */
+	u_long	tcps_segstimed;		/* segs where we tried to get rtt */
+	u_long	tcps_rttupdated;	/* times we succeeded */
+	u_long	tcps_delack;		/* delayed acks sent */
+	u_long	tcps_timeoutdrop;	/* conn. dropped in rxmt timeout */
+	u_long	tcps_rexmttimeo;	/* retransmit timeouts */
+	u_long	tcps_persisttimeo;	/* persist timeouts */
+	u_long	tcps_keeptimeo;		/* keepalive timeouts */
+	u_long	tcps_keepprobe;		/* keepalive probes sent */
+	u_long	tcps_keepdrops;		/* connections dropped in keepalive */
+
+	u_long	tcps_sndtotal;		/* total packets sent */
+	u_long	tcps_sndpack;		/* data packets sent */
+	u_long	tcps_sndbyte;		/* data bytes sent */
+	u_long	tcps_sndrexmitpack;	/* data packets retransmitted */
+	u_long	tcps_sndrexmitbyte;	/* data bytes retransmitted */
+	u_long	tcps_sndacks;		/* ack-only packets sent */
+	u_long	tcps_sndprobe;		/* window probes sent */
+	u_long	tcps_sndurg;		/* packets sent with URG only */
+	u_long	tcps_sndwinup;		/* window update-only packets sent */
+	u_long	tcps_sndctrl;		/* control (SYN|FIN|RST) packets sent */
+
+	u_long	tcps_rcvtotal;		/* total packets received */
+	u_long	tcps_rcvpack;		/* packets received in sequence */
+	u_long	tcps_rcvbyte;		/* bytes received in sequence */
+	u_long	tcps_rcvbadsum;		/* packets received with ccksum errs */
+	u_long	tcps_rcvbadoff;		/* packets received with bad offset */
+/*	u_long	tcps_rcvshort;	*/	/* packets received too short */
+	u_long	tcps_rcvduppack;	/* duplicate-only packets received */
+	u_long	tcps_rcvdupbyte;	/* duplicate-only bytes received */
+	u_long	tcps_rcvpartduppack;	/* packets with some duplicate data */
+	u_long	tcps_rcvpartdupbyte;	/* dup. bytes in part-dup. packets */
+	u_long	tcps_rcvoopack;		/* out-of-order packets received */
+	u_long	tcps_rcvoobyte;		/* out-of-order bytes received */
+	u_long	tcps_rcvpackafterwin;	/* packets with data after window */
+	u_long	tcps_rcvbyteafterwin;	/* bytes rcvd after window */
+	u_long	tcps_rcvafterclose;	/* packets rcvd after "close" */
+	u_long	tcps_rcvwinprobe;	/* rcvd window probe packets */
+	u_long	tcps_rcvdupack;		/* rcvd duplicate acks */
+	u_long	tcps_rcvacktoomuch;	/* rcvd acks for unsent data */
+	u_long	tcps_rcvackpack;	/* rcvd ack packets */
+	u_long	tcps_rcvackbyte;	/* bytes acked by rcvd acks */
+	u_long	tcps_rcvwinupd;		/* rcvd window update packets */
+/*	u_long	tcps_pawsdrop;	*/	/* segments dropped due to PAWS */
+	u_long	tcps_predack;		/* times hdr predict ok for acks */
+	u_long	tcps_preddat;		/* times hdr predict ok for data pkts */
+	u_long	tcps_socachemiss;	/* tcp_last_so misses */
+	u_long	tcps_didnuttin;		/* Times tcp_output didn't do anything XXX */
+};
+
+extern struct	tcpstat tcpstat;	/* tcp statistics */
+extern u_int32_t	tcp_now;		/* for RFC 1323 timestamps */
+
+#endif
diff --git a/slirp/tcpip.h b/slirp/tcpip.h
new file mode 100644
index 000000000..82708b09c
--- /dev/null
+++ b/slirp/tcpip.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcpip.h	8.1 (Berkeley) 6/10/93
+ * tcpip.h,v 1.3 1994/08/21 05:27:40 paul Exp
+ */
+
+#ifndef _TCPIP_H_
+#define _TCPIP_H_
+
+/*
+ * Tcp+ip header, after ip options removed.
+ */
+struct tcpiphdr {
+	struct 	ipovly ti_i;		/* overlaid ip structure */
+	struct	tcphdr ti_t;		/* tcp header */
+};
+#define	ti_next		ti_i.ih_next
+#define	ti_prev		ti_i.ih_prev
+#define	ti_x1		ti_i.ih_x1
+#define	ti_pr		ti_i.ih_pr
+#define	ti_len		ti_i.ih_len
+#define	ti_src		ti_i.ih_src
+#define	ti_dst		ti_i.ih_dst
+#define	ti_sport	ti_t.th_sport
+#define	ti_dport	ti_t.th_dport
+#define	ti_seq		ti_t.th_seq
+#define	ti_ack		ti_t.th_ack
+#define	ti_x2		ti_t.th_x2
+#define	ti_off		ti_t.th_off
+#define	ti_flags	ti_t.th_flags
+#define	ti_win		ti_t.th_win
+#define	ti_sum		ti_t.th_sum
+#define	ti_urp		ti_t.th_urp
+
+/*
+ * Just a clean way to get to the first byte
+ * of the packet
+ */
+struct tcpiphdr_2 {
+	struct tcpiphdr dummy;
+	char first_char;
+};
+
+#endif
diff --git a/slirp/udp.c b/slirp/udp.c
new file mode 100644
index 000000000..76a4fcc97
--- /dev/null
+++ b/slirp/udp.c
@@ -0,0 +1,654 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)udp_usrreq.c	8.4 (Berkeley) 1/21/94
+ * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP
+ * Copyright (c) 1995 Danny Gasparovski.
+ * 
+ * Please read the file COPYRIGHT for the 
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include "ip_icmp.h"
+
+struct udpstat udpstat;
+
+struct socket udb;
+
+/*
+ * UDP protocol implementation.
+ * Per RFC 768, August, 1980.
+ */
+#ifndef	COMPAT_42
+int	udpcksum = 1;
+#else
+int	udpcksum = 0;		/* XXX */
+#endif
+
+struct	socket *udp_last_so = &udb;
+
+void
+udp_init()
+{
+	udb.so_next = udb.so_prev = &udb;
+}
+/* m->m_data  points at ip packet header 
+ * m->m_len   length ip packet 
+ * ip->ip_len length data (IPDU)
+ */
+void
+udp_input(m, iphlen)
+	register struct mbuf *m;
+	int iphlen;
+{
+	register struct ip *ip;
+	register struct udphdr *uh;
+/*	struct mbuf *opts = 0;*/
+	int len;
+	struct ip save_ip; 
+	struct socket *so;
+	
+	DEBUG_CALL("udp_input");
+	DEBUG_ARG("m = %lx", (long)m);
+	DEBUG_ARG("iphlen = %d", iphlen);
+	
+	udpstat.udps_ipackets++;
+
+	/*
+	 * Strip IP options, if any; should skip this,
+	 * make available to user, and use on returned packets,
+	 * but we don't yet have a way to check the checksum
+	 * with options still present.
+	 */
+	if(iphlen > sizeof(struct ip)) {
+		ip_stripoptions(m, (struct mbuf *)0);
+		iphlen = sizeof(struct ip);
+	}
+
+	/*
+	 * Get IP and UDP header together in first mbuf.
+	 */
+	ip = mtod(m, struct ip *);
+	uh = (struct udphdr *)((caddr_t)ip + iphlen);
+
+	/*
+	 * Make mbuf data length reflect UDP length.
+	 * If not enough data to reflect UDP length, drop.
+	 */
+	len = ntohs((u_int16_t)uh->uh_ulen);
+
+	if (ip->ip_len != len) {
+		if (len > ip->ip_len) {
+			udpstat.udps_badlen++;
+			goto bad;
+		}
+		m_adj(m, len - ip->ip_len);
+		ip->ip_len = len;
+	}
+	
+	/*
+	 * Save a copy of the IP header in case we want restore it
+	 * for sending an ICMP error message in response.
+	 */
+	save_ip = *ip; 
+	save_ip.ip_len+= iphlen;         /* tcp_input subtracts this */
+
+	/*
+	 * Checksum extended UDP header and data.
+	 */
+	if (udpcksum && uh->uh_sum) {
+	  ((struct ipovly *)ip)->ih_next = 0;
+	  ((struct ipovly *)ip)->ih_prev = 0;
+	  ((struct ipovly *)ip)->ih_x1 = 0;
+	  ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
+	  /* keep uh_sum for ICMP reply
+	   * uh->uh_sum = cksum(m, len + sizeof (struct ip)); 
+	   * if (uh->uh_sum) { 
+	   */
+	  if(cksum(m, len + sizeof(struct ip))) {
+	    udpstat.udps_badsum++;
+	    goto bad;
+	  }
+	}
+
+        /*
+         *  handle DHCP/BOOTP
+         */
+        if (ntohs(uh->uh_dport) == BOOTP_SERVER) {
+            bootp_input(m);
+            goto bad;
+        }
+
+	/*
+	 * Locate pcb for datagram.
+	 */
+	so = udp_last_so;
+	if (so->so_lport != uh->uh_sport ||
+	    so->so_laddr.s_addr != ip->ip_src.s_addr) {
+		struct socket *tmp;
+		
+		for (tmp = udb.so_next; tmp != &udb; tmp = tmp->so_next) {
+			if (tmp->so_lport == uh->uh_sport &&
+			    tmp->so_laddr.s_addr == ip->ip_src.s_addr) {
+				tmp->so_faddr.s_addr = ip->ip_dst.s_addr;
+				tmp->so_fport = uh->uh_dport;
+				so = tmp;
+				break;
+			}
+		}
+		if (tmp == &udb) {
+		  so = NULL;
+		} else {
+		  udpstat.udpps_pcbcachemiss++;
+		  udp_last_so = so;
+		}
+	}
+	
+	if (so == NULL) {
+	  /*
+	   * If there's no socket for this packet,
+	   * create one
+	   */
+	  if ((so = socreate()) == NULL) goto bad;
+	  if(udp_attach(so) == -1) {
+	    DEBUG_MISC((dfd," udp_attach errno = %d-%s\n", 
+			errno,strerror(errno)));
+	    sofree(so);
+	    goto bad;
+	  }
+	  
+	  /*
+	   * Setup fields
+	   */
+	  /* udp_last_so = so; */
+	  so->so_laddr = ip->ip_src;
+	  so->so_lport = uh->uh_sport;
+	  so->so_faddr = ip->ip_dst; /* XXX */
+	  so->so_fport = uh->uh_dport; /* XXX */
+	  
+	  if ((so->so_iptos = udp_tos(so)) == 0)
+	    so->so_iptos = ip->ip_tos;
+	  
+	  /*
+	   * XXXXX Here, check if it's in udpexec_list,
+	   * and if it is, do the fork_exec() etc.
+	   */
+	}
+
+	iphlen += sizeof(struct udphdr);
+	m->m_len -= iphlen;
+	m->m_data += iphlen;
+
+	/*
+	 * Now we sendto() the packet.
+	 */
+	if (so->so_emu)
+	   udp_emu(so, m);
+
+	if(sosendto(so,m) == -1) {
+	  m->m_len += iphlen;
+	  m->m_data -= iphlen;
+	  *ip=save_ip;
+	  DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
+	  icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));  
+	}
+
+	m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */
+
+	/* restore the orig mbuf packet */
+	m->m_len += iphlen;
+	m->m_data -= iphlen;
+	*ip=save_ip;
+	so->so_m=m;         /* ICMP backup */
+
+	return;
+bad:
+	m_freem(m);
+	/* if (opts) m_freem(opts); */
+	return;
+}
+
+int udp_output2(struct socket *so, struct mbuf *m, 
+                struct sockaddr_in *saddr, struct sockaddr_in *daddr,
+                int iptos)
+{
+	register struct udpiphdr *ui;
+	int error = 0;
+
+	DEBUG_CALL("udp_output");
+	DEBUG_ARG("so = %lx", (long)so);
+	DEBUG_ARG("m = %lx", (long)m);
+	DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
+	DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);
+
+	/*
+	 * Adjust for header
+	 */
+	m->m_data -= sizeof(struct udpiphdr);
+	m->m_len += sizeof(struct udpiphdr);
+	
+	/*
+	 * Fill in mbuf with extended UDP header
+	 * and addresses and length put into network format.
+	 */
+	ui = mtod(m, struct udpiphdr *);
+	ui->ui_next = ui->ui_prev = 0;
+	ui->ui_x1 = 0;
+	ui->ui_pr = IPPROTO_UDP;
+	ui->ui_len = htons(m->m_len - sizeof(struct ip)); /* + sizeof (struct udphdr)); */
+	/* XXXXX Check for from-one-location sockets, or from-any-location sockets */
+        ui->ui_src = saddr->sin_addr;
+	ui->ui_dst = daddr->sin_addr;
+	ui->ui_sport = saddr->sin_port;
+	ui->ui_dport = daddr->sin_port;
+	ui->ui_ulen = ui->ui_len;
+
+	/*
+	 * Stuff checksum and output datagram.
+	 */
+	ui->ui_sum = 0;
+	if (udpcksum) {
+	    if ((ui->ui_sum = cksum(m, /* sizeof (struct udpiphdr) + */ m->m_len)) == 0)
+		ui->ui_sum = 0xffff;
+	}
+	((struct ip *)ui)->ip_len = m->m_len;
+
+	((struct ip *)ui)->ip_ttl = ip_defttl;
+	((struct ip *)ui)->ip_tos = iptos;
+	
+	udpstat.udps_opackets++;
+	
+	error = ip_output(so, m);
+	
+	return (error);
+}
+
+int udp_output(struct socket *so, struct mbuf *m, 
+               struct sockaddr_in *addr)
+
+{
+    struct sockaddr_in saddr, daddr;
+
+    saddr = *addr;
+    if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr)
+        saddr.sin_addr.s_addr = so->so_faddr.s_addr;
+    daddr.sin_addr = so->so_laddr;
+    daddr.sin_port = so->so_lport;
+    
+    return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
+}
+
+int
+udp_attach(so)
+     struct socket *so;
+{
+  struct sockaddr_in addr;
+	
+  if((so->s = socket(AF_INET,SOCK_DGRAM,0)) != -1) {
+    /*
+     * Here, we bind() the socket.  Although not really needed
+     * (sendto() on an unbound socket will bind it), it's done
+     * here so that emulation of ytalk etc. don't have to do it
+     */
+    addr.sin_family = AF_INET;
+    addr.sin_port = 0;
+    addr.sin_addr.s_addr = INADDR_ANY;
+    if(bind(so->s, (struct sockaddr *)&addr, sizeof(addr))<0) {
+      int lasterrno=errno;
+      close(so->s);
+      so->s=-1;
+      errno=lasterrno;
+    } else {
+      /* success, insert in queue */
+      so->so_expire = curtime + SO_EXPIRE;
+      insque(so,&udb);
+    }
+  }
+  return(so->s);
+}
+
+void
+udp_detach(so)
+	struct socket *so;
+{
+	close(so->s);
+	/* if (so->so_m) m_free(so->so_m);    done by sofree */
+
+	sofree(so);
+}
+
+struct tos_t udptos[] = {
+	{0, 53, IPTOS_LOWDELAY, 0},			/* DNS */
+	{517, 517, IPTOS_LOWDELAY, EMU_TALK},	/* talk */
+	{518, 518, IPTOS_LOWDELAY, EMU_NTALK},	/* ntalk */
+	{0, 7648, IPTOS_LOWDELAY, EMU_CUSEEME},	/* Cu-Seeme */
+	{0, 0, 0, 0}
+};
+
+u_int8_t
+udp_tos(so)
+	struct socket *so;
+{
+	int i = 0;
+	
+	while(udptos[i].tos) {
+		if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
+		    (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
+		    	so->so_emu = udptos[i].emu;
+			return udptos[i].tos;
+		}
+		i++;
+	}
+	
+	return 0;
+}
+
+#ifdef EMULATE_TALK
+#include "talkd.h"
+#endif
+
+/*
+ * Here, talk/ytalk/ntalk requests must be emulated
+ */
+void
+udp_emu(so, m)
+	struct socket *so;
+	struct mbuf *m;
+{
+	struct sockaddr_in addr;
+        int addrlen = sizeof(addr);
+#ifdef EMULATE_TALK
+	CTL_MSG_OLD *omsg;
+	CTL_MSG *nmsg;
+	char buff[sizeof(CTL_MSG)];
+	u_char type;
+	
+struct talk_request {
+	struct talk_request *next;
+	struct socket *udp_so;
+	struct socket *tcp_so;
+} *req;
+	
+	static struct talk_request *req_tbl = 0;	
+	
+#endif
+	
+struct cu_header {
+	char 	dest[8];
+	short 	family;
+	u_short	port;
+	u_long	addr;
+} *cu_head;
+
+	switch(so->so_emu) {
+
+#ifdef EMULATE_TALK
+	 case EMU_TALK:
+	 case EMU_NTALK:
+		/*
+		 * Talk emulation. We always change the ctl_addr to get
+		 * some answers from the daemon. When an ANNOUNCE comes,
+		 * we send LEAVE_INVITE to the local daemons. Also when a
+		 * DELETE comes, we send copies to the local daemons.
+		 */
+		if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
+			return;
+		
+#define	IS_OLD	(so->so_emu == EMU_TALK)
+
+#define COPY_MSG(dest, src) { dest->type = src->type; \
+			      dest->id_num = src->id_num; \
+			      dest->pid = src->pid; \
+			      dest->addr = src->addr; \
+			      dest->ctl_addr = src->ctl_addr; \
+			      memcpy(&dest->l_name, &src->l_name, NAME_SIZE_OLD); \
+			      memcpy(&dest->r_name, &src->r_name, NAME_SIZE_OLD); \
+	         	      memcpy(&dest->r_tty, &src->r_tty, TTY_SIZE); }
+
+#define OTOSIN(ptr, field) ((struct sockaddr_in *)&ptr->field)
+/* old_sockaddr to sockaddr_in */
+
+
+		if (IS_OLD) {  		/* old talk */
+			omsg = mtod(m, CTL_MSG_OLD*);
+			nmsg = (CTL_MSG *) buff;
+			type = omsg->type;
+			OTOSIN(omsg, ctl_addr)->sin_port = addr.sin_port;
+			OTOSIN(omsg, ctl_addr)->sin_addr = our_addr;
+			strncpy(omsg->l_name, getlogin(), NAME_SIZE_OLD);
+		} else {		/* new talk */	
+			omsg = (CTL_MSG_OLD *) buff;
+			nmsg = mtod(m, CTL_MSG *);
+			type = nmsg->type;
+			OTOSIN(nmsg, ctl_addr)->sin_port = addr.sin_port;
+			OTOSIN(nmsg, ctl_addr)->sin_addr = our_addr;
+			strncpy(nmsg->l_name, getlogin(), NAME_SIZE_OLD);
+		}
+		
+		if (type == LOOK_UP) 
+			return;		/* for LOOK_UP this is enough */
+			
+		if (IS_OLD) {		/* make a copy of the message */
+			COPY_MSG(nmsg, omsg);
+			nmsg->vers = 1;
+			nmsg->answer = 0;
+		} else
+			COPY_MSG(omsg, nmsg);
+
+		/*
+		 * If if is an ANNOUNCE message, we go through the
+		 * request table to see if a tcp port has already
+		 * been redirected for this socket. If not, we solisten()
+		 * a new socket and add this entry to the table.
+		 * The port number of the tcp socket and our IP
+		 * are put to the addr field of the message structures.
+		 * Then a LEAVE_INVITE is sent to both local daemon
+		 * ports, 517 and 518. This is why we have two copies
+		 * of the message, one in old talk and one in new talk
+		 * format.
+		 */ 
+
+		if (type == ANNOUNCE) {
+			int s;
+			u_short temp_port;
+			
+			for(req = req_tbl; req; req = req->next)
+				if (so == req->udp_so)
+					break;  	/* found it */
+					
+			if (!req) {	/* no entry for so, create new */
+				req = (struct talk_request *)
+					malloc(sizeof(struct talk_request));
+				req->udp_so = so;
+				req->tcp_so = solisten(0,		
+					OTOSIN(omsg, addr)->sin_addr.s_addr,	
+					OTOSIN(omsg, addr)->sin_port,
+					SS_FACCEPTONCE);
+				req->next = req_tbl;
+				req_tbl = req;
+			}			
+			
+			/* replace port number in addr field */
+			addrlen = sizeof(addr);
+			getsockname(req->tcp_so->s, 
+					(struct sockaddr *) &addr,
+					&addrlen);		
+			OTOSIN(omsg, addr)->sin_port = addr.sin_port;
+			OTOSIN(omsg, addr)->sin_addr = our_addr;
+			OTOSIN(nmsg, addr)->sin_port = addr.sin_port;
+			OTOSIN(nmsg, addr)->sin_addr = our_addr;		
+			
+			/* send LEAVE_INVITEs */
+			temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
+			OTOSIN(omsg, ctl_addr)->sin_port = 0;
+			OTOSIN(nmsg, ctl_addr)->sin_port = 0;
+			omsg->type = nmsg->type = LEAVE_INVITE;			
+			
+			s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
+			addr.sin_addr = our_addr;
+			addr.sin_family = AF_INET;
+			addr.sin_port = htons(517);
+			sendto(s, (char *)omsg, sizeof(*omsg), 0, 
+				(struct sockaddr *)&addr, sizeof(addr));
+			addr.sin_port = htons(518);
+			sendto(s, (char *)nmsg, sizeof(*nmsg), 0,
+				(struct sockaddr *) &addr, sizeof(addr));
+			close(s) ;
+
+			omsg->type = nmsg->type = ANNOUNCE; 
+			OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
+			OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
+		}
+		
+		/*	
+		 * If it is a DELETE message, we send a copy to the
+		 * local daemons. Then we delete the entry corresponding
+		 * to our socket from the request table.
+		 */
+		
+		if (type == DELETE) {
+			struct talk_request *temp_req, *req_next;
+			int s;
+			u_short temp_port;
+			
+			temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
+			OTOSIN(omsg, ctl_addr)->sin_port = 0;
+			OTOSIN(nmsg, ctl_addr)->sin_port = 0;
+			
+			s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
+			addr.sin_addr = our_addr;
+			addr.sin_family = AF_INET;
+			addr.sin_port = htons(517);
+			sendto(s, (char *)omsg, sizeof(*omsg), 0,
+				(struct sockaddr *)&addr, sizeof(addr));
+			addr.sin_port = htons(518);
+			sendto(s, (char *)nmsg, sizeof(*nmsg), 0,
+				(struct sockaddr *)&addr, sizeof(addr));
+			close(s);
+			
+			OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
+			OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
+
+			/* delete table entry */
+			if (so == req_tbl->udp_so) {
+				temp_req = req_tbl;
+				req_tbl = req_tbl->next;
+				free(temp_req);
+			} else {
+				temp_req = req_tbl;
+				for(req = req_tbl->next; req; req = req_next) {
+					req_next = req->next;
+					if (so == req->udp_so) {
+						temp_req->next = req_next;
+						free(req);
+						break;
+					} else {
+						temp_req = req;
+					}
+				}
+			}
+		}
+		
+		return;		
+#endif
+		
+	case EMU_CUSEEME:
+	
+		/*
+		 * Cu-SeeMe emulation.
+		 * Hopefully the packet is more that 16 bytes long. We don't
+		 * do any other tests, just replace the address and port
+		 * fields.
+		 */ 
+		if (m->m_len >= sizeof (*cu_head)) {
+			if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
+				return;
+			cu_head = mtod(m, struct cu_header *);
+			cu_head->port = addr.sin_port;
+			cu_head->addr = (u_long) our_addr.s_addr;
+		}
+		
+		return;
+	}
+}
+
+struct socket *
+udp_listen(port, laddr, lport, flags)
+	u_int port;
+	u_int32_t laddr;
+	u_int lport;
+	int flags;
+{
+	struct sockaddr_in addr;
+	struct socket *so;
+	int addrlen = sizeof(struct sockaddr_in), opt = 1;
+	
+	if ((so = socreate()) == NULL) {
+		free(so);
+		return NULL;
+	}
+	so->s = socket(AF_INET,SOCK_DGRAM,0);
+	so->so_expire = curtime + SO_EXPIRE;
+	insque(so,&udb);
+
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = INADDR_ANY;
+	addr.sin_port = port;
+
+	if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
+		udp_detach(so);
+		return NULL;
+	}
+	setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
+/*	setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int)); */
+	
+	getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
+	so->so_fport = addr.sin_port;
+	if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr)
+	   so->so_faddr = our_addr;
+	else
+	   so->so_faddr = addr.sin_addr;
+	
+	so->so_lport = lport;
+	so->so_laddr.s_addr = laddr;
+	if (flags != SS_FACCEPTONCE)
+	   so->so_expire = 0;
+	
+	so->so_state = SS_ISFCONNECTED;
+	
+	return so;
+}
diff --git a/slirp/udp.h b/slirp/udp.h
new file mode 100644
index 000000000..195b1bfff
--- /dev/null
+++ b/slirp/udp.h
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)udp.h	8.1 (Berkeley) 6/10/93
+ * udp.h,v 1.3 1994/08/21 05:27:41 paul Exp
+ */
+
+#ifndef _UDP_H_
+#define _UDP_H_
+
+#define UDP_TTL 0x60
+#define UDP_UDPDATALEN 16192
+
+extern struct socket *udp_last_so;
+
+/*
+ * Udp protocol header.
+ * Per RFC 768, September, 1981.
+ */
+struct udphdr {
+	u_int16_t	uh_sport;		/* source port */
+	u_int16_t	uh_dport;		/* destination port */
+	int16_t	uh_ulen;		/* udp length */
+	u_int16_t	uh_sum;			/* udp checksum */
+};
+
+/*
+ * UDP kernel structures and variables.
+ */
+struct udpiphdr {
+	        struct  ipovly ui_i;            /* overlaid ip structure */
+	        struct  udphdr ui_u;            /* udp header */
+};
+#define ui_next         ui_i.ih_next
+#define ui_prev         ui_i.ih_prev
+#define ui_x1           ui_i.ih_x1
+#define ui_pr           ui_i.ih_pr
+#define ui_len          ui_i.ih_len
+#define ui_src          ui_i.ih_src
+#define ui_dst          ui_i.ih_dst
+#define ui_sport        ui_u.uh_sport
+#define ui_dport        ui_u.uh_dport
+#define ui_ulen         ui_u.uh_ulen
+#define ui_sum          ui_u.uh_sum
+
+struct udpstat {
+	                                /* input statistics: */
+	        u_long  udps_ipackets;          /* total input packets */
+	        u_long  udps_hdrops;            /* packet shorter than header */
+	        u_long  udps_badsum;            /* checksum error */
+	        u_long  udps_badlen;            /* data length larger than packet */
+	        u_long  udps_noport;            /* no socket on port */
+	        u_long  udps_noportbcast;       /* of above, arrived as broadcast */
+	        u_long  udps_fullsock;          /* not delivered, input socket full */
+	        u_long  udpps_pcbcachemiss;     /* input packets missing pcb cache */
+	                                /* output statistics: */
+	        u_long  udps_opackets;          /* total output packets */
+};
+
+/*
+ * Names for UDP sysctl objects
+ */
+#define UDPCTL_CHECKSUM         1       /* checksum UDP packets */
+#define UDPCTL_MAXID            2
+
+extern struct udpstat udpstat;
+extern struct socket udb;
+
+void udp_init _P((void));
+void udp_input _P((register struct mbuf *, int));
+int udp_output _P((struct socket *, struct mbuf *, struct sockaddr_in *));
+int udp_attach _P((struct socket *));
+void udp_detach _P((struct socket *));
+u_int8_t udp_tos _P((struct socket *));
+void udp_emu _P((struct socket *, struct mbuf *));
+struct socket * udp_listen _P((u_int, u_int32_t, u_int, int));
+int udp_output2(struct socket *so, struct mbuf *m, 
+                struct sockaddr_in *saddr, struct sockaddr_in *daddr,
+                int iptos);
+#endif