slirp: move sources to src/ subdirectory

Prepare for making slirp/ a standalone project.

Remove some useless includes while at it.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190212162524.31504-5-marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

1 files changed, 0 insertions, 1556 deletions

diff --git a/slirp/tcp_input.c b/slirp/tcp_input.c
deleted file mode 100644
index b10477fc57..0000000000
--- a/slirp/tcp_input.c
+++ /dev/null
@@ -1,1556 +0,0 @@
-/*
- * 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. 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"
-
-#define	TCPREXMTTHRESH 3
-
-#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).
- */
-#define	TCP_REASS(tp, ti, m, so, flags) { \
-	if ((ti)->ti_seq == (tp)->rcv_nxt && \
-        tcpfrag_list_empty(tp) && \
-	    (tp)->t_state == TCPS_ESTABLISHED) { \
-		tp->t_flags |= TF_DELACK; \
-		(tp)->rcv_nxt += (ti)->ti_len; \
-		flags = (ti)->ti_flags & TH_FIN; \
-		if (so->so_emu) { \
-			if (tcp_emu((so),(m))) sbappend(so, (m)); \
-		} else \
-			sbappend((so), (m)); \
-	} else { \
-		(flags) = tcp_reass((tp), (ti), (m)); \
-		tp->t_flags |= TF_ACKNOW; \
-	} \
-}
-
-static void tcp_dooptions(struct tcpcb *tp, uint8_t *cp, int cnt,
-                          struct tcpiphdr *ti);
-static void tcp_xmit_timer(register struct tcpcb *tp, int rtt);
-
-static int
-tcp_reass(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==NULL after become established to
-	 * force pre-ESTABLISHED data up to user socket.
-	 */
-        if (ti == NULL)
-		goto present;
-
-	/*
-	 * Find a segment which begins after this one does.
-	 */
-	for (q = tcpfrag_list_first(tp); !tcpfrag_list_end(q, tp);
-            q = tcpiphdr_next(q))
-		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 (!tcpfrag_list_end(tcpiphdr_prev(q), tp)) {
-		register int i;
-		q = tcpiphdr_prev(q);
-		/* 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) {
-				m_free(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 = tcpiphdr_next(q);
-	}
-	ti->ti_mbuf = m;
-
-	/*
-	 * While we overlap succeeding segments trim them or,
-	 * if they are completely covered, dequeue them.
-	 */
-	while (!tcpfrag_list_end(q, 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(q->ti_mbuf, i);
-			break;
-		}
-		q = tcpiphdr_next(q);
-		m = tcpiphdr_prev(q)->ti_mbuf;
-		remque(tcpiphdr2qlink(tcpiphdr_prev(q)));
-		m_free(m);
-	}
-
-	/*
-	 * Stick new segment in its place.
-	 */
-	insque(tcpiphdr2qlink(ti), tcpiphdr2qlink(tcpiphdr_prev(q)));
-
-present:
-	/*
-	 * Present data to user, advancing rcv_nxt through
-	 * completed sequence space.
-	 */
-	if (!TCPS_HAVEESTABLISHED(tp->t_state))
-		return (0);
-	ti = tcpfrag_list_first(tp);
-	if (tcpfrag_list_end(ti, 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(tcpiphdr2qlink(ti));
-		m = ti->ti_mbuf;
-		ti = tcpiphdr_next(ti);
-		if (so->so_state & SS_FCANTSENDMORE)
-			m_free(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);
-	return (flags);
-}
-
-/*
- * TCP input routine, follows pages 65-76 of the
- * protocol specification dated September, 1981 very closely.
- */
-void
-tcp_input(struct mbuf *m, int iphlen, struct socket *inso, unsigned short af)
-{
-	struct ip save_ip, *ip;
-	struct ip6 save_ip6, *ip6;
-	register struct tcpiphdr *ti;
-	char *optp = NULL;
-	int optlen = 0;
-	int len, tlen, off;
-        register struct tcpcb *tp = NULL;
-	register int tiflags;
-        struct socket *so = NULL;
-	int todrop, acked, ourfinisacked, needoutput = 0;
-	int iss = 0;
-	uint32_t tiwin;
-	int ret;
-	struct sockaddr_storage lhost, fhost;
-	struct sockaddr_in *lhost4, *fhost4;
-	struct sockaddr_in6 *lhost6, *fhost6;
-    struct gfwd_list *ex_ptr;
-    Slirp *slirp;
-
-	DEBUG_CALL("tcp_input");
-	DEBUG_ARG("m = %p  iphlen = %2d  inso = %p",
-              m, iphlen, inso);
-
-	/*
-	 * If called with m == 0, then we're continuing the connect
-	 */
-	if (m == NULL) {
-		so = inso;
-		slirp = so->slirp;
-
-		/* Re-set a few variables */
-		tp = sototcpcb(so);
-		m = so->so_m;
-                so->so_m = NULL;
-		ti = so->so_ti;
-		tiwin = ti->ti_win;
-		tiflags = ti->ti_flags;
-
-		goto cont_conn;
-	}
-	slirp = m->slirp;
-
-	ip = mtod(m, struct ip *);
-	ip6 = mtod(m, struct ip6 *);
-
-	switch (af) {
-	case AF_INET:
-	    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.
-	     */
-	    save_ip = *ip;
-	    save_ip.ip_len += iphlen;
-
-	    /*
-	     * Get IP and TCP header together in first mbuf.
-	     * Note: IP leaves IP header in first mbuf.
-	     */
-	    m->m_data -= sizeof(struct tcpiphdr) - sizeof(struct ip)
-	                                         - sizeof(struct tcphdr);
-	    m->m_len += sizeof(struct tcpiphdr) - sizeof(struct ip)
-	                                        - sizeof(struct tcphdr);
-	    ti = mtod(m, struct tcpiphdr *);
-
-	    /*
-	     * Checksum extended TCP header and data.
-	     */
-	    tlen = ip->ip_len;
-	    tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
-	    memset(&ti->ih_mbuf, 0 , sizeof(struct mbuf_ptr));
-	    memset(&ti->ti, 0, sizeof(ti->ti));
-	    ti->ti_x0 = 0;
-	    ti->ti_src = save_ip.ip_src;
-	    ti->ti_dst = save_ip.ip_dst;
-	    ti->ti_pr = save_ip.ip_p;
-	    ti->ti_len = htons((uint16_t)tlen);
-	    break;
-
-	case AF_INET6:
-	    /*
-	     * Save a copy of the IP header in case we want restore it
-	     * for sending an ICMP error message in response.
-	     */
-	    save_ip6 = *ip6;
-	    /*
-	     * Get IP and TCP header together in first mbuf.
-	     * Note: IP leaves IP header in first mbuf.
-	     */
-	    m->m_data -= sizeof(struct tcpiphdr) - (sizeof(struct ip6)
-	                                         + sizeof(struct tcphdr));
-	    m->m_len  += sizeof(struct tcpiphdr) - (sizeof(struct ip6)
-	                                         + sizeof(struct tcphdr));
-	    ti = mtod(m, struct tcpiphdr *);
-
-	    tlen = ip6->ip_pl;
-	    tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
-	    memset(&ti->ih_mbuf, 0 , sizeof(struct mbuf_ptr));
-	    memset(&ti->ti, 0, sizeof(ti->ti));
-	    ti->ti_x0 = 0;
-	    ti->ti_src6 = save_ip6.ip_src;
-	    ti->ti_dst6 = save_ip6.ip_dst;
-	    ti->ti_nh6 = save_ip6.ip_nh;
-	    ti->ti_len = htons((uint16_t)tlen);
-	    break;
-
-	default:
-	    g_assert_not_reached();
-	}
-
-	len = ((sizeof(struct tcpiphdr) - sizeof(struct tcphdr)) + tlen);
-	if (cksum(m, len)) {
-	    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) {
-	  goto drop;
-	}
-	tlen -= off;
-	ti->ti_len = tlen;
-	if (off > sizeof (struct tcphdr)) {
-	  optlen = off - sizeof (struct tcphdr);
-	  optp = mtod(m, char *) + sizeof (struct tcpiphdr);
-	}
-	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:
-	lhost.ss_family = af;
-	fhost.ss_family = af;
-	switch (af) {
-	case AF_INET:
-	    lhost4 = (struct sockaddr_in *) &lhost;
-	    lhost4->sin_addr = ti->ti_src;
-	    lhost4->sin_port = ti->ti_sport;
-	    fhost4 = (struct sockaddr_in *) &fhost;
-	    fhost4->sin_addr = ti->ti_dst;
-	    fhost4->sin_port = ti->ti_dport;
-	    break;
-	case AF_INET6:
-	    lhost6 = (struct sockaddr_in6 *) &lhost;
-	    lhost6->sin6_addr = ti->ti_src6;
-	    lhost6->sin6_port = ti->ti_sport;
-	    fhost6 = (struct sockaddr_in6 *) &fhost;
-	    fhost6->sin6_addr = ti->ti_dst6;
-	    fhost6->sin6_port = ti->ti_dport;
-	    break;
-	default:
-	    g_assert_not_reached();
-	}
-
-	so = solookup(&slirp->tcp_last_so, &slirp->tcb, &lhost, &fhost);
-
-	/*
-	 * 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 == NULL) {
-          /* TODO: IPv6 */
-          if (slirp->restricted) {
-            /* Any hostfwds will have an existing socket, so we only get here
-             * for non-hostfwd connections. These should be dropped, unless it
-             * happens to be a guestfwd.
-             */
-            for (ex_ptr = slirp->guestfwd_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
-                if (ex_ptr->ex_fport == ti->ti_dport &&
-                    ti->ti_dst.s_addr == ex_ptr->ex_addr.s_addr) {
-                    break;
-                }
-            }
-            if (!ex_ptr) {
-                goto dropwithreset;
-            }
-          }
-
-	  if ((tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) != TH_SYN)
-	    goto dropwithreset;
-
-          so = socreate(slirp);
-	  if (tcp_attach(so) < 0) {
-            g_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);
-
-	  so->lhost.ss = lhost;
-	  so->fhost.ss = fhost;
-
-	  so->so_iptos = tcp_tos(so);
-	  if (so->so_iptos == 0) {
-	      switch (af) {
-	      case AF_INET:
-	          so->so_iptos = ((struct ip *)ti)->ip_tos;
-	          break;
-	      case AF_INET6:
-	          break;
-	      default:
-	          g_assert_not_reached();
-	      }
-	  }
-
-	  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 == NULL)
-		goto dropwithreset;
-	if (tp->t_state == TCPS_CLOSED)
-		goto drop;
-
-	tiwin = ti->ti_win;
-
-	/*
-	 * Segment received on connection.
-	 * Reset idle time and keep-alive timer.
-	 */
-	tp->t_idle = 0;
-	if (slirp_do_keepalive)
-	   tp->t_timer[TCPT_KEEP] = TCPTV_KEEPINTVL;
-	else
-	   tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_IDLE;
-
-	/*
-	 * 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, (uint8_t *)optp, optlen, ti);
-
-	/*
-	 * 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 &&
-	    ti->ti_seq == tp->rcv_nxt &&
-	    tiwin && tiwin == tp->snd_wnd &&
-	    tp->snd_nxt == tp->snd_max) {
-		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.
-				 */
-				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;
-				sodrop(so, acked);
-				tp->snd_una = ti->ti_ack;
-				m_free(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;
-
-				/*
-				 * 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 &&
-		    tcpfrag_list_empty(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.
-			 */
-			tp->rcv_nxt += ti->ti_len;
-			/*
-			 * Add data to socket buffer.
-			 */
-			if (so->so_emu) {
-				if (tcp_emu(so,m)) sbappend(so, m);
-			} else
-				sbappend(so, m);
-
-			/*
-			 * If this is a short packet, then ACK now - with Nagel
-			 *	congestion avoidance sender won't send more until
-			 *	he gets an ACK.
-			 *
-			 * It is better to not delay acks at all to maximize
-			 * TCP throughput.  See RFC 2581.
-			 */
-			tp->t_flags |= TF_ACKNOW;
-			tcp_output(tp);
-			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
-	   */
-          /* TODO: IPv6 */
-	  if (af == AF_INET &&
-	         (so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
-	         slirp->vnetwork_addr.s_addr) {
-	    if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr &&
-		so->so_faddr.s_addr != slirp->vnameserver_addr.s_addr) {
-		/* May be an add exec */
-		for (ex_ptr = slirp->guestfwd_list; ex_ptr;
-		     ex_ptr = ex_ptr->ex_next) {
-		  if(ex_ptr->ex_fport == so->so_fport &&
-		     so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
-		    so->so_state |= SS_CTL;
-		    break;
-		  }
-		}
-		if (so->so_state & SS_CTL) {
-		    goto cont_input;
-		}
-	    }
-	    /* 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, so->so_ffamily) == -1) &&
-              (errno != EAGAIN) &&
-              (errno != EINPROGRESS) && (errno != EWOULDBLOCK)
-          ) {
-	    uint8_t code;
-	    DEBUG_MISC(" tcp fconnect errno = %d-%s", 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, af);
-	    } else {
-	      switch (af) {
-	      case AF_INET:
-		code = ICMP_UNREACH_NET;
-		if (errno == EHOSTUNREACH) {
-		  code = ICMP_UNREACH_HOST;
-		}
-		break;
-	      case AF_INET6:
-		code = ICMP6_UNREACH_NO_ROUTE;
-		if (errno == EHOSTUNREACH) {
-		  code = ICMP6_UNREACH_ADDRESS;
-		}
-		break;
-	      default:
-		g_assert_not_reached();
-	      }
-	      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);
-	      switch (af) {
-	      case AF_INET:
-		m->m_data += sizeof(struct tcpiphdr) - sizeof(struct ip)
-						     - sizeof(struct tcphdr);
-		m->m_len  -= sizeof(struct tcpiphdr) - sizeof(struct ip)
-						     - sizeof(struct tcphdr);
-		*ip = save_ip;
-		icmp_send_error(m, ICMP_UNREACH, code, 0, strerror(errno));
-		break;
-	      case AF_INET6:
-		m->m_data += sizeof(struct tcpiphdr) - (sizeof(struct ip6)
-						     + sizeof(struct tcphdr));
-		m->m_len  -= sizeof(struct tcpiphdr) - (sizeof(struct ip6)
-						     + sizeof(struct tcphdr));
-		*ip6 = save_ip6;
-		icmp6_send_error(m, ICMP6_UNREACH, code);
-		break;
-	      default:
-		g_assert_not_reached();
-	      }
-	    }
-            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;
-	    /*
-	     * Initialize receive sequence numbers now so that we can send a
-	     * valid RST if the remote end rejects our connection.
-	     */
-	    tp->irs = ti->ti_seq;
-	    tcp_rcvseqinit(tp);
-	    tcp_template(tp);
-	  }
-	  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, (uint8_t *)optp, optlen, ti);
-
-	  if (iss)
-	    tp->iss = iss;
-	  else
-	    tp->iss = slirp->tcp_iss;
-	  slirp->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;
-	  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) {
-                                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)) {
-			soisfconnected(so);
-			tp->t_state = TCPS_ESTABLISHED;
-
-			(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;
-		}
-		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.
-	 * 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.
-	 */
-	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;
-		}
-		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);
-		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) {
-		if (todrop >= 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;
-			} else {
-				goto dropafterack;
-			}
-		}
-		m_adj(m, -todrop);
-		ti->ti_len -= todrop;
-		tiflags &= ~(TH_PUSH|TH_FIN);
-	}
-
-	/*
-	 * 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:
-	case TCPS_ESTABLISHED:
-	case TCPS_FIN_WAIT_1:
-	case TCPS_FIN_WAIT_2:
-	case TCPS_CLOSE_WAIT:
-		tp->t_state = TCPS_CLOSED;
-                tcp_close(tp);
-		goto drop;
-
-	case TCPS_CLOSING:
-	case TCPS_LAST_ACK:
-	case TCPS_TIME_WAIT:
-                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;
-		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_PERSISTENT_MASK;
-		    so->so_state |= SS_NOFDREF; /* CTL_CMD */
-		  } else {
-		    needoutput = 1;
-		    tp->t_state = TCPS_FIN_WAIT_1;
-		  }
-		} else {
-		  soisfconnected(so);
-		}
-
-		(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) {
-			  DEBUG_MISC(" dup ack  m = %p  so = %p", m, 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;
-					unsigned 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)) {
-			goto dropafterack;
-		}
-		acked = ti->ti_ack - tp->snd_una;
-
-		/*
-		 * If 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 (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 unsigned cw = tp->snd_cwnd;
-		  register unsigned 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;
-			sodrop(so, (int)so->so_snd.sb_cc);
-			ourfinisacked = 1;
-		} else {
-			sodrop(so, acked);
-			tp->snd_wnd -= acked;
-			ourfinisacked = 0;
-		}
-		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) {
-					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;
-			}
-			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) {
-                                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))))) {
-		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:
-
-	/*
-	 * If this is a small packet, then ACK now - with Nagel
-	 *      congestion avoidance sender won't send more until
-	 *      he gets an ACK.
-	 */
-	if (ti->ti_len && (unsigned)ti->ti_len <= 5 &&
-	    ((struct tcpiphdr_2 *)ti)->first_char == (char)27) {
-		tp->t_flags |= TF_ACKNOW;
-	}
-
-	/*
-	 * 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);
-	} 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.
-			 */
-			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;
-			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;
-		}
-	}
-
-	/*
-	 * 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_free(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, af);
-	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, af);
-	}
-
-	return;
-
-drop:
-	/*
-	 * Drop space held by incoming segment and return.
-	 */
-	m_free(m);
-}
-
-static void
-tcp_dooptions(struct tcpcb *tp, uint8_t *cp, int cnt, struct tcpiphdr *ti)
-{
-	uint16_t mss;
-	int opt, optlen;
-
-	DEBUG_CALL("tcp_dooptions");
-	DEBUG_ARG("tp = %p  cnt=%i", 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;
-		}
-	}
-}
-
-/*
- * Collect new round-trip time estimate
- * and update averages and current timeout.
- */
-
-static void
-tcp_xmit_timer(register struct tcpcb *tp, int rtt)
-{
-	register short delta;
-
-	DEBUG_CALL("tcp_xmit_timer");
-	DEBUG_ARG("tp = %p", tp);
-	DEBUG_ARG("rtt = %d", rtt);
-
-	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(struct tcpcb *tp, unsigned offer)
-{
-	struct socket *so = tp->t_socket;
-	int mss;
-
-	DEBUG_CALL("tcp_mss");
-	DEBUG_ARG("tp = %p", tp);
-	DEBUG_ARG("offer = %d", offer);
-
-	switch (so->so_ffamily) {
-	case AF_INET:
-            mss = MIN(IF_MTU, IF_MRU) - sizeof(struct tcphdr)
-	                              - sizeof(struct ip);
-	    break;
-	case AF_INET6:
-            mss = MIN(IF_MTU, IF_MRU) - sizeof(struct tcphdr)
-	                              - sizeof(struct ip6);
-	    break;
-	default:
-	    g_assert_not_reached();
-	}
-
-	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(" returning mss = %d", mss);
-
-	return mss;
-}