revert tcp_input.c to before 07/01/1999 - this seems to solve the mysterious

data corruptions and panics that people have experienced.  by reverting
we loose tcp signatures and ipv6 cleanups, the code looked correct to me.

1 files changed, 272 insertions, 543 deletions

diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 6ad3623a7ee..4eb50c0a275 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcp_input.c,v 1.41 1999/07/13 21:57:42 deraadt Exp $	*/
+/*	$OpenBSD: tcp_input.c,v 1.42 1999/07/17 23:41:46 provos Exp $	*/
 /*	$NetBSD: tcp_input.c,v 1.23 1996/02/13 23:43:44 christos Exp $	*/
 
 /*
@@ -48,12 +48,6 @@ You should have received a copy of the license with this software. If you
 didn't get a copy, you may request one from <license@ipv6.nrl.navy.mil>.
 */
 
-/*
- * XXX - At this point, the TUBA support is likely to be hopelessly broken.
- * That's the bad news. The good news is that doing it again and doing it
- * right shouldn't be hard now that the IPv4 dependencies are isolated.
- */
-
 #ifndef TUBA_INCLUDE
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -94,19 +88,17 @@ didn't get a copy, you may request one from <license@ipv6.nrl.navy.mil>.
 #include <netinet6/ipv6_var.h>
 #include <netinet6/tcpipv6.h>
 
+struct	tcpiphdr tcp_saveti;
+struct  tcpipv6hdr tcp_saveti6;
+
 /* for the packet header length in the mbuf */
 #define M_PH_LEN(m)      (((struct mbuf *)(m))->m_pkthdr.len)
 #define M_V6_LEN(m)      (M_PH_LEN(m) - sizeof(struct ipv6))
 #define M_V4_LEN(m)      (M_PH_LEN(m) - sizeof(struct ip))
 #endif /* INET6 */
 
-#ifdef INET6
-char tcp_savebuf[sizeof(struct ipv6) + sizeof(struct tcphdr)];
-#else /* INET6 */
-char tcp_savebuf[sizeof(struct ip) + sizeof(struct tcphdr)];
-#endif /* INET6 */
-
 int	tcprexmtthresh = 3;
+struct	tcpiphdr tcp_saveti;
 int	tcptv_keep_init = TCPTV_KEEP_INIT;
 
 extern u_long sb_max;
@@ -313,9 +305,9 @@ tcp_input(struct mbuf *m, ...)
 #else
 tcp_input(m, va_alist)
 	register struct mbuf *m;
-	va_dcl
 #endif
 {
+	register struct tcpiphdr *ti;
 	register struct inpcb *inp;
 	caddr_t optp = NULL;
 	int optlen = 0;
@@ -325,6 +317,7 @@ tcp_input(m, va_alist)
 	struct socket *so = NULL;
 	int todrop, acked, ourfinisacked, needoutput = 0;
 	short ostate = 0;
+	struct in_addr laddr;
 	int dropsocket = 0;
 	int iss = 0;
 	u_long tiwin;
@@ -333,19 +326,14 @@ tcp_input(m, va_alist)
 	int iphlen;
 	va_list ap;
 	register struct tcphdr *th;
-	unsigned int pf;
 #ifdef IPSEC
 	struct tdb *tdb = NULL;
 #endif /* IPSEC */
-	union {
-		caddr_t p;
-#ifdef INET
-		struct ip *ip;
-#endif /* INET */
 #ifdef INET6
-		struct ipv6 *ipv6;
-#endif /* INET */
-	} nhu;
+	struct in6_addr laddr6;
+	unsigned short is_ipv6;     /* Type of incoming datagram. */
+	struct ipv6 *ipv6 = NULL;
+#endif /* INET6 */
 
 	va_start(ap, m);
 	iphlen = va_arg(ap, int);
@@ -362,113 +350,87 @@ tcp_input(m, va_alist)
 		m->m_pkthdr.tdbi = NULL;
 	}
 #endif /* IPSEC */
-
+#ifdef INET6
 	/*
-	 * Before we do ANYTHING, we have to figure out what network protocol
-	 * is underneath the TCP header in this packet.
-	 *
-	 * For IPv4 and IPv6, options don't really do anything at this layer
-	 * and therefore are stripped off.
+	 * Before we do ANYTHING, we have to figure out if it's TCP/IPv6 or
+	 * TCP/IPv4.
  	 */
-#if defined(INET) && defined(INET6)
-	switch (mtod(m, struct ip *)->ip_v) {
-#else /* defined(INET) && defined(INET6) */
-	switch (-1) {
-	case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-	case 4:
-		pf = PF_INET;
-
-#ifdef DIAGNOSTIC
-		if (iphlen < sizeof(struct ip)) {
-			m_freem(m);
-			return;
-		}
-#endif /* DIAGNOSTIC */
-
-		if (iphlen > sizeof(struct ip)) {
-			ip_stripoptions(m, (struct mbuf *)0);
-			iphlen = sizeof(struct ip);
-		}
-		break;
-#endif /* INET */
-#ifdef INET6
-	case 6:
-		pf = PF_INET6;
-
-#ifdef DIAGNOSTIC
-		if (iphlen < sizeof(struct ipv6)) {
-			m_freem(m);
-			return;
-		}
-#endif /* DIAGNOSTIC */
-
-		if (iphlen > sizeof(struct ipv6)) {
-			ipv6_stripoptions(m, iphlen);
-			iphlen = sizeof(struct ipv6);
-		}
-		break;
+	is_ipv6 = mtod(m, struct ip *)->ip_v == 6;
 #endif /* INET6 */
-	default:
-		m_freem(m);
-		return;
-	}
 
 	/*
 	 * Get IP and TCP header together in first mbuf.
 	 * Note: IP leaves IP header in first mbuf.
 	 */
+#ifndef INET6
+	ti = mtod(m, struct tcpiphdr *);
+#else /* INET6 */
+	if (!is_ipv6)
+#endif /* INET6 */
+	if (iphlen > sizeof (struct ip))
+		ip_stripoptions(m, (struct mbuf *)0);
 	if (m->m_len < iphlen + sizeof(struct tcphdr)) {
 		if ((m = m_pullup2(m, iphlen + sizeof(struct tcphdr))) == 0) {
 			tcpstat.tcps_rcvshort++;
 			return;
 		}
+#ifndef INET6
+		ti = mtod(m, struct tcpiphdr *);
+#endif /* INET6 */
 	}
 
 	tlen = m->m_pkthdr.len - iphlen;
 
+#ifdef INET6
 	/*
-	 * Checksum extended TCP header and data.
+	 * After that, do initial segment processing which is still very
+	 * dependent on what IP version you're using.
 	 */
-#if defined(INET) && defined(INET6)
-	switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-	switch (-1) {
-	case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-	case PF_INET:
-		{
-			struct ipovly *ipovly;
 
-			ipovly = mtod(m, struct ipovly *);
+	if (is_ipv6) {
+#ifdef DIAGNOSTIC
+	  if (iphlen < sizeof(struct ipv6)) {
+	    m_freem(m);
+	    return;
+	  }
+#endif /* DIAGNOSTIC */
 
-			len = sizeof (struct ip) + tlen;
-			bzero(ipovly->ih_x1, sizeof ipovly->ih_x1);
-			ipovly->ih_len = (u_int16_t)tlen;
-			HTONS(ipovly->ih_len);
+	  /* strip off any options */
+	  if (iphlen > sizeof(struct ipv6)) {
+	    ipv6_stripoptions(m, iphlen);
+	    iphlen = sizeof(struct ipv6);
+	  }
 
-			if (in_cksum(m, len)) {
-				tcpstat.tcps_rcvbadsum++;
-				goto drop;
-			}
-		}
-		break;
-#endif /* INET */
-#ifdef INET6
-	case PF_INET6:
-		if (in6_cksum(m, IPPROTO_TCP, tlen, sizeof(struct ipv6))) {
-			tcpstat.tcps_rcvbadsum++;
-			goto drop;
-		} /* endif in6_cksum */
-		break;
+	  ti = NULL;
+	  ipv6 = mtod(m, struct ipv6 *);
+
+	  if (in6_cksum(m, IPPROTO_TCP, tlen, sizeof(struct ipv6))) {
+	    tcpstat.tcps_rcvbadsum++;
+	    goto drop;
+	  } /* endif in6_cksum */
+	} else {
+	  ti = mtod(m, struct tcpiphdr *);
 #endif /* INET6 */
-	}
 
+	/*
+	 * Checksum extended TCP header and data.
+	 */
+#ifndef INET6
+	tlen = ((struct ip *)ti)->ip_len;
+#endif /* INET6 */
+	len = sizeof (struct ip) + tlen;
+	bzero(ti->ti_x1, sizeof ti->ti_x1);
+	ti->ti_len = (u_int16_t)tlen;
+	HTONS(ti->ti_len);
+	if ((ti->ti_sum = in_cksum(m, len)) != 0) {
+		tcpstat.tcps_rcvbadsum++;
+		goto drop;
+	}
+#ifdef INET6
+	}
+#endif /* INET6 */
 #endif /* TUBA_INCLUDE */
 
-	nhu.p = mtod(m, caddr_t);
 	th = (struct tcphdr *)(mtod(m, caddr_t) + iphlen);
 
 	/*
@@ -487,6 +449,12 @@ tcp_input(m, va_alist)
 				tcpstat.tcps_rcvshort++;
 				return;
 			}
+#ifdef INET6
+			if (is_ipv6)
+			  ipv6 = mtod(m, struct ipv6 *);
+			else
+#endif /* INET6 */
+			ti = mtod(m, struct tcpiphdr *);
 			th = (struct tcphdr *)(mtod(m, caddr_t) + iphlen);
 		}
 		optlen = off - sizeof (struct tcphdr);
@@ -523,51 +491,25 @@ tcp_input(m, va_alist)
 	 * Locate pcb for segment.
 	 */
 findpcb:
-#if defined(INET) && defined(INET6)
-	switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-	switch (-1) {
-	case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-	case PF_INET:
-		inp = in_pcbhashlookup(&tcbtable, nhu.ip->ip_src,
-			th->th_sport, nhu.ip->ip_dst, th->th_dport);
-		break;
-#endif /* INET */
 #ifdef INET6
-	case PF_INET6:
-		inp = in6_pcbhashlookup(&tcbtable, &nhu.ipv6->ipv6_src,
-			th->th_sport, &nhu.ipv6->ipv6_dst, th->th_dport);
-		break;
+	if (is_ipv6) {
+	  inp = in6_pcbhashlookup(&tcbtable, &ipv6->ipv6_src, th->th_sport,
+				 &ipv6->ipv6_dst, th->th_dport);
+	} else
 #endif /* INET6 */
-	}
-
+	inp = in_pcbhashlookup(&tcbtable, ti->ti_src, ti->ti_sport,
+	    ti->ti_dst, ti->ti_dport);
 	if (inp == 0) {
 		++tcpstat.tcps_pcbhashmiss;
-#if defined(INET) && defined(INET6)
-		switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-		switch (-1) {
-		case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-		case PF_INET:
-			inp = in_pcblookup(&tcbtable, &nhu.ip->ip_src,
-				th->th_sport, &nhu.ip->ip_dst, th->th_dport,
-				INPLOOKUP_WILDCARD);
-			break;
-#endif /* INET */
 #ifdef INET6
-		case PF_INET6:
-			inp = in_pcblookup(&tcbtable, &nhu.ipv6->ipv6_src,
-				th->th_sport, &nhu.ipv6->ipv6_dst,
-				th->th_dport,
-				INPLOOKUP_WILDCARD | INPLOOKUP_IPV6);
-			break;
+		if (is_ipv6)
+			inp = in_pcblookup(&tcbtable, &ipv6->ipv6_src,
+			    th->th_sport, &ipv6->ipv6_dst, th->th_dport,
+			    INPLOOKUP_WILDCARD | INPLOOKUP_IPV6);
+		else
 #endif /* INET6 */
-		}
-
+		inp = in_pcblookup(&tcbtable, &ti->ti_src, ti->ti_sport,
+		    &ti->ti_dst, ti->ti_dport, INPLOOKUP_WILDCARD);
 		/*
 		 * If the state is CLOSED (i.e., TCB does not exist) then
 		 * all data in the incoming segment is discarded.
@@ -596,8 +538,12 @@ findpcb:
 	if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) {
 		if (so->so_options & SO_DEBUG) {
 			ostate = tp->t_state;
-			bcopy(mtod(m, caddr_t), tcp_savebuf,
-				iphlen + sizeof(struct tcphdr));
+#ifdef INET6
+			if (is_ipv6)
+			  tcp_saveti6 = *(mtod(m, struct tcpipv6hdr *));
+			else
+#endif /* INET6 */
+			tcp_saveti = *ti;
 		}
 		if (so->so_options & SO_ACCEPTCONN) {
 			struct socket *so1;
@@ -645,57 +591,48 @@ findpcb:
 			 * to the new one.
 			 */
 			{
-				int flags = inp->inp_flags;
-				struct inpcb *oldinpcb = inp;
+			  int flags = inp->inp_flags;
+			  struct inpcb *oldinpcb = inp;
 			  
-				inp = (struct inpcb *)so->so_pcb;
-				inp->inp_flags |=
-					(flags & (INP_IPV6 | INP_IPV6_UNDEC
-					| INP_IPV6_MAPPED));
-				if ((inp->inp_flags & INP_IPV6) &&
-						!(inp->inp_flags &
-						INP_IPV6_MAPPED)) {
-					inp->inp_ipv6.ipv6_hoplimit = 
-						oldinpcb->inp_ipv6.
-						ipv6_hoplimit;
-					inp->inp_ipv6.ipv6_versfl = 
-						oldinpcb->inp_ipv6.ipv6_versfl;
-				}
+			  inp = (struct inpcb *)so->so_pcb;
+			  inp->inp_flags |= (flags & (INP_IPV6 | INP_IPV6_UNDEC
+						      | INP_IPV6_MAPPED));
+			  if ((inp->inp_flags & INP_IPV6) &&
+			      !(inp->inp_flags & INP_IPV6_MAPPED)) {
+			    inp->inp_ipv6.ipv6_hoplimit = 
+			      oldinpcb->inp_ipv6.ipv6_hoplimit;
+			    inp->inp_ipv6.ipv6_versfl = 
+			      oldinpcb->inp_ipv6.ipv6_versfl;
+			  }
 			}
 #else /* INET6 */
 			inp = (struct inpcb *)so->so_pcb;
 #endif /* INET6 */
 			inp->inp_lport = th->th_dport;
-#if defined(INET) && defined(INET6)
-			switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-			switch (-1) {
-			case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-			case PF_INET:
 #ifdef INET6
-				if (inp->inp_flags & INP_IPV6) {
-					/* v4 to v6 socket */
-					CREATE_IPV6_MAPPED(inp->inp_laddr6,
-						nhu.ip->ip_dst.s_addr);
-				} else
+			if (is_ipv6) {
+			  inp->inp_laddr6 = ipv6->ipv6_dst;
+			  inp->inp_fflowinfo = htonl(0x0fffffff) & 
+			    ipv6->ipv6_versfl;
+			  
+			  /*inp->inp_options = ipv6_srcroute();*/ /* soon. */
+			  /* still need to tweak outbound options
+			     processing to include this mbuf in
+			     the right place and put the correct
+			     NextHdr values in the right places.
+			     XXX  rja */
+			} else {
+			  if (inp->inp_flags & INP_IPV6) {/* v4 to v6 socket */
+			    CREATE_IPV6_MAPPED(inp->inp_laddr6,
+			      ti->ti_dst.s_addr);
+			  } else {
 #endif /* INET6 */
-				{
-					inp->inp_laddr = nhu.ip->ip_dst;
-					inp->inp_options = ip_srcroute();
-				}
-				break;
-#endif /* INET */
-#ifdef INET6
-			case PF_INET6:
-				inp->inp_laddr6 = nhu.ipv6->ipv6_dst;
-				inp->inp_fflowinfo = htonl(0x0fffffff) & 
-					nhu.ipv6->ipv6_versfl;
-				break;
+			    inp->inp_laddr = ti->ti_dst;
+			    inp->inp_options = ip_srcroute();
+#if INET6
+			  }
+			};
 #endif /* INET6 */
-			}
-
 			in_pcbrehash(inp);
 			tp = intotcpcb(inp);
 			tp->t_state = TCPS_LISTEN;
@@ -703,8 +640,7 @@ findpcb:
 			/* Compute proper scaling value from buffer space
 			 */
 			while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
-			   TCP_MAXWIN << tp->request_r_scale <
-			   so->so_rcv.sb_hiwat)
+			   TCP_MAXWIN << tp->request_r_scale < so->so_rcv.sb_hiwat)
 				tp->request_r_scale++;
 		}
 	}
@@ -716,23 +652,12 @@ findpcb:
 	    (inp->inp_seclevel[SL_ESP_TRANS] >= IPSEC_LEVEL_REQUIRE &&
 	     !(m->m_flags & M_CONF))) {
 #ifdef notyet
-#if defined(INET) && defined(INET6)
-		switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-		switch (-1) {
-		case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-		case PF_INET:
-			icmp_error(m, ICMP_BLAH, ICMP_BLAH, 0, 0);
-			break;
-#endif /* INET */
 #ifdef INET6
-		case PF_INET6:
+		if (is_ipv6)
 			ipv6_icmp_error(m, ICMPV6_BLAH, ICMPV6_BLAH, 0);
-			break;
+		else
 #endif /* INET6 */
-		}
+		icmp_error(m, ICMP_BLAH, ICMP_BLAH, 0, 0);
 #endif /* notyet */
 		tcpstat.tcps_rcvnosec++;
 		goto drop;
@@ -759,15 +684,9 @@ findpcb:
 	 * Process options if not in LISTEN state,
 	 * else do it below (after getting remote address).
 	 */
-	if (tp->t_state != TCPS_LISTEN)
-#ifdef TCP_SIGNATURE
-		if (optp || (tp->t_flags & TF_SIGNATURE))
-#else /* TCP_SIGNATURE */
-		if (optp)
-#endif /* TCP_SIGNATURE */
-			if (tcp_dooptions(tp, optp, optlen, th, m, iphlen,
-					&ts_present, &ts_val, &ts_ecr))
-				goto drop;
+	if (optp && tp->t_state != TCPS_LISTEN)
+		tcp_dooptions(tp, optp, optlen, th,
+			&ts_present, &ts_val, &ts_ecr);
 
 #ifdef TCP_SACK
 	if (!tp->sack_disable) {
@@ -930,6 +849,10 @@ findpcb:
 	 */
 	case TCPS_LISTEN: {
 		struct mbuf *am;
+		register struct sockaddr_in *sin;
+#ifdef INET6
+		register struct sockaddr_in6 *sin6;
+#endif /* INET6 */
 
 		if (tiflags & TH_RST)
 			goto drop;
@@ -938,27 +861,17 @@ findpcb:
 		if ((tiflags & TH_SYN) == 0)
 			goto drop;
 		if (th->th_dport == th->th_sport) {
-#if defined(INET) && defined(INET6)
-			switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-			switch (-1) {
-			case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-			case PF_INET:
-				if (nhu.ip->ip_src.s_addr ==
-						nhu.ip->ip_dst.s_addr)
-					goto drop;
-				break;
-#endif /* INET */
 #ifdef INET6
-			case PF_INET6:
-				if (IN6_ARE_ADDR_EQUAL(&nhu.ipv6->ipv6_src,
-						&nhu.ipv6->ipv6_dst))
-					goto drop;
-				break;
+		  if (is_ipv6) {
+		    if (IN6_ARE_ADDR_EQUAL(&ipv6->ipv6_src, &ipv6->ipv6_dst))
+		      goto drop;
+		  } else {
+#endif /* INET6 */
+		    if (ti->ti_dst.s_addr == ti->ti_src.s_addr)
+		      goto drop;
+#ifdef INET6
+		  }
 #endif /* INET6 */
-			}
 		}
 
 		/*
@@ -968,172 +881,118 @@ findpcb:
 		 */
 		if (m->m_flags & (M_BCAST|M_MCAST))
 		  goto drop;
-#if defined(INET) && defined(INET6)
-		switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-		switch (-1) {
-		case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-		case PF_INET:
-			if (nhu.ip->ip_dst.s_addr == INADDR_BROADCAST)
-				goto drop;
-			if (IN_MULTICAST(nhu.ip->ip_dst.s_addr))
-				goto drop;
-			break;
-#endif /* INET */
 #ifdef INET6
-		case PF_INET6:
-			if (IN6_IS_ADDR_MULTICAST(&nhu.ipv6->ipv6_dst))
+		if (is_ipv6) {
+			/* XXX What about IPv6 Anycasting ?? :-(  rja */
+			if (IN6_IS_ADDR_MULTICAST(&ipv6->ipv6_dst))
 				goto drop;
-			break;
+		} else
 #endif /* INET6 */
-		}
-
+		if (IN_MULTICAST(ti->ti_dst.s_addr))
+			goto drop;
 		am = m_get(M_DONTWAIT, MT_SONAME);	/* XXX */
 		if (am == NULL)
 			goto drop;
-
-#if defined(INET) && defined(INET6)
-		switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-		switch (-1) {
-		case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-		case PF_INET:
 #ifdef INET6
-			/*
-			 * Letting v4 incoming datagrams to reach valid 
-			 * PF_INET6 sockets causes some overhead here.
-			 */
-			if (inp->inp_flags & INP_IPV6) {
-				struct sockaddr_in6 *sin6;
-				struct in6_addr laddr6;
-
-				if (!(inp->inp_flags & (INP_IPV6_UNDEC |
-						INP_IPV6_MAPPED))) {
-					m_freem(am);
-					goto drop;
-				}
-
-				am->m_len = sizeof(struct sockaddr_in6);
-				sin6 = mtod(am, struct sockaddr_in6 *);
-				sin6->sin6_family = AF_INET6;
-				sin6->sin6_len = sizeof(struct sockaddr_in6);
-				CREATE_IPV6_MAPPED(sin6->sin6_addr,
-					nhu.ip->ip_src.s_addr);
-				sin6->sin6_port = th->th_sport;
-				sin6->sin6_flowinfo = 0;
-
-				laddr6 = inp->inp_laddr6;
-				if (inp->inp_laddr.s_addr == INADDR_ANY)
-					break;
-				CREATE_IPV6_MAPPED(inp->inp_laddr6,
-					nhu.ip->ip_dst.s_addr);
-
-				/*
-				 * The pcb initially has the v6 default hop
-				 * limit set. We're sending v4 packets, so we
-				 * need to set the v4 ttl and tos.
-				 */
-				inp->inp_ip.ip_ttl = ip_defttl;
-				inp->inp_ip.ip_tos = 0;
-
-				if (in6_pcbconnect(inp, am)) {
-					inp->inp_laddr6 = laddr6;
-					m_freem(am);
-					goto drop;
-				}
-			} else /* (inp->inp_flags & INP_IPV6) */
+		if (is_ipv6) {
+		  /*
+		   * This is probably the place to set the tp->pf value.
+		   * (Don't forget to do it in the v4 code as well!)
+		   *
+		   * Also, remember to blank out things like flowlabel, or
+		   * set flowlabel for accepted sockets in v6.
+		   *
+		   * FURTHERMORE, this is PROBABLY the place where the whole
+		   * business of key munging is set up for passive
+		   * connections.
+		   */
+		  am->m_len = sizeof(struct sockaddr_in6);
+		  sin6 = mtod(am, struct sockaddr_in6 *);
+		  sin6->sin6_family = AF_INET6;
+		  sin6->sin6_len = sizeof(struct sockaddr_in6);
+		  sin6->sin6_addr = ipv6->ipv6_src;
+		  sin6->sin6_port = th->th_sport;
+		  sin6->sin6_flowinfo = htonl(0x0fffffff) &
+		    inp->inp_ipv6.ipv6_versfl;
+		  laddr6 = inp->inp_laddr6;
+		  if (IN6_IS_ADDR_UNSPECIFIED(&inp->inp_laddr6))
+		    inp->inp_laddr6 = ipv6->ipv6_dst;
+		  /* This is a good optimization. */
+		  if (in6_pcbconnect(inp, am)) {
+		    inp->inp_laddr6 = laddr6;
+		    (void) m_free(am);
+		    goto drop;
+		  } /* endif in6_pcbconnect() */
+		  tp->pf = PF_INET6;
+		} else {
+		  /*
+		   * Letting v4 incoming datagrams to reach valid 
+		   * PF_INET6 sockets causes some overhead here.
+		   */
+		  if (inp->inp_flags & INP_IPV6) {
+		    if (!(inp->inp_flags & (INP_IPV6_UNDEC|INP_IPV6_MAPPED))) {
+		      (void) m_free(am);
+		      goto drop;
+		    }
+
+		    am->m_len = sizeof(struct sockaddr_in6);
+		    
+		    sin6 = mtod(am, struct sockaddr_in6 *);
+		    sin6->sin6_family = AF_INET6;
+		    sin6->sin6_len = sizeof(*sin6);
+		    CREATE_IPV6_MAPPED(sin6->sin6_addr, ti->ti_src.s_addr);
+		    sin6->sin6_port = th->th_sport;
+		    sin6->sin6_flowinfo = 0;
+
+		    laddr6 = inp->inp_laddr6;
+		    if (inp->inp_laddr.s_addr == INADDR_ANY)
+		      CREATE_IPV6_MAPPED(inp->inp_laddr6, ti->ti_dst.s_addr);
+		    
+		    /*
+		     * The pcb initially has the v6 default hoplimit
+		     * set. We're sending v4 packets so we need to set
+		     * the v4 ttl and tos.
+		     */
+		    inp->inp_ip.ip_ttl = ip_defttl;
+		    inp->inp_ip.ip_tos = 0;
+		    
+		    if (in6_pcbconnect(inp, am)) {
+		      inp->inp_laddr6 = laddr6;
+		      (void) m_freem(am);
+		      goto drop;
+		    }
+		    tp->pf = PF_INET;
+		  } else { 
 #endif /* INET6 */
-			{
-				struct sockaddr_in *sin;
-				struct in_addr laddr;
-
-				am->m_len = sizeof(struct sockaddr_in);
-				sin = mtod(am, struct sockaddr_in *);
-				sin->sin_family = AF_INET;
-				sin->sin_len = sizeof(struct sockaddr_in);
-				sin->sin_addr = nhu.ip->ip_src;
-				sin->sin_port = th->th_sport;
-				bzero((caddr_t)sin->sin_zero,
-					sizeof(sin->sin_zero));
-				laddr = inp->inp_laddr;
-				if (inp->inp_laddr.s_addr == INADDR_ANY)
-					inp->inp_laddr = nhu.ip->ip_dst;
-				if (in_pcbconnect(inp, am)) {
-					inp->inp_laddr = laddr;
-					m_free(am);
-					goto drop;
-				}
-			} /* (inp->inp_flags & INP_IPV6) */
-			tp->pf = PF_INET;
-			break;
-#endif /* INET */
+		am->m_len = sizeof (struct sockaddr_in);
+		sin = mtod(am, struct sockaddr_in *);
+		sin->sin_family = AF_INET;
+		sin->sin_len = sizeof(*sin);
+		sin->sin_addr = ti->ti_src;
+		sin->sin_port = ti->ti_sport;
+		bzero((caddr_t)sin->sin_zero, sizeof(sin->sin_zero));
+		laddr = inp->inp_laddr;
+		if (inp->inp_laddr.s_addr == INADDR_ANY)
+			inp->inp_laddr = ti->ti_dst;
+		if (in_pcbconnect(inp, am)) {
+			inp->inp_laddr = laddr;
+			(void) m_free(am);
+			goto drop;
+		}
+		(void) m_free(am);
 #ifdef INET6
-		case PF_INET6:
-			{
-				struct sockaddr_in6 *sin6;
-				struct in6_addr laddr6;
-
-				/*
-			 	 * This is probably the place to set the tp->pf
-				 * value. (Don't forget to do it in the v4 code
-				 * as well!)
-				 *
-				 * Also, remember to blank out things like
-				 * flowlabel, or set flowlabel for accepted
-				 * sockets in v6.
-				 */
-
-				am->m_len = sizeof(struct sockaddr_in6);
-				sin6 = mtod(am, struct sockaddr_in6 *);
-				sin6->sin6_family = AF_INET6;
-				sin6->sin6_len = sizeof(struct sockaddr_in6);
-				sin6->sin6_addr = nhu.ipv6->ipv6_src;
-				sin6->sin6_port = th->th_sport;
-				sin6->sin6_flowinfo = htonl(0x0fffffff) &
-					inp->inp_ipv6.ipv6_versfl;
-				laddr6 = inp->inp_laddr6;
-
-				if (IN6_IS_ADDR_UNSPECIFIED(&inp->inp_laddr6))
-					inp->inp_laddr6 = nhu.ipv6->ipv6_dst;
-				/* This is a good optimization. */
-				if (in6_pcbconnect(inp, am)) {
-					inp->inp_laddr6 = laddr6;
-					m_free(am);
-					goto drop;
-				}
-			}
-
-			tp->pf = PF_INET6;
-			break;
+		  }  /* if (inp->inp_flags & INP_IPV6) */
+		} /* if (is_ipv6) */
 #endif /* INET6 */
-		}
-
-		m_free(am);
 		tp->t_template = tcp_template(tp);
 		if (tp->t_template == 0) {
 			tp = tcp_drop(tp, ENOBUFS);
 			dropsocket = 0;		/* socket is already gone */
 			goto drop;
 		}
-
-#ifdef TCP_SIGNATURE
-		if (optp || (tp->t_flags & TF_SIGNATURE)) {
-#else /* TCP_SIGNATURE */
-		if (optp) {
-#endif /* TCP_SIGNATURE */
-			m->m_data -= iphlen + off;
-			m->m_len  += iphlen + off;
-			if (tcp_dooptions(tp, optp, optlen, th, m, iphlen,
-					&ts_present, &ts_val, &ts_ecr))
-				goto drop;
-			m->m_data += iphlen + off;
-			m->m_len  -= iphlen + off;
-		}
-
+		if (optp)
+			tcp_dooptions(tp, optp, optlen, th,
+				&ts_present, &ts_val, &ts_ecr);
 #ifdef TCP_SACK
 		/*
 		 * If peer did not send a SACK_PERMITTED option (i.e., if
@@ -1434,7 +1293,7 @@ trimthenstep6:
 	 *	Close the tcb.
 	 */
 	if (tiflags & TH_RST) {
-		if (th->th_seq != tp->last_ack_sent)
+		if (ti->ti_seq != tp->last_ack_sent)
 			goto drop;
 
 		switch (tp->t_state) {
@@ -2060,9 +1919,14 @@ dodata:							/* XXX */
 			break;
 		}
 	}
-
-	if (so->so_options & SO_DEBUG)
-		tcp_trace(TA_INPUT, ostate, tp, tcp_savebuf, 0, tlen);
+	if (so->so_options & SO_DEBUG) {
+#ifdef INET6
+		if (tp->pf == PF_INET6)
+			tcp_trace(TA_INPUT, ostate, tp, (caddr_t) &tcp_saveti6, 0, tlen);
+		else
+#endif /* INET6 */
+			tcp_trace(TA_INPUT, ostate, tp, (caddr_t) &tcp_saveti, 0, tlen);
+	}
 
 	/*
 	 * Return any desired output.
@@ -2103,36 +1967,26 @@ dropwithreset:
 	 */
 	if ((tiflags & TH_RST) || m->m_flags & (M_BCAST|M_MCAST))
 	  goto drop;
-#if defined(INET) && defined(INET6)
-	switch (pf) {
-#else /* defined(INET) && defined(INET6) */
-	switch (-1) {
-	case -1:
-#endif /* defined(INET) && defined(INET6) */
-#ifdef INET
-	case PF_INET:
-		if (mtod(m, struct ip *)->ip_dst.s_addr == INADDR_BROADCAST)
-			goto drop;
-		if (IN_MULTICAST(mtod(m, struct ip *)->ip_dst.s_addr))
-			goto drop;
-		break;
-#endif /* INET */
 #ifdef INET6
-	case PF_INET6:
-		if (IN6_IS_ADDR_MULTICAST(&mtod(m, struct ipv6 *)->ipv6_dst))
-			goto drop;
-		break;
+	if (is_ipv6) {
+	  /* For following calls to tcp_respond */
+	  ti = mtod(m, struct tcpiphdr *);
+	  if (IN6_IS_ADDR_MULTICAST(&ipv6->ipv6_dst))
+	    goto drop;
+	} else {
 #endif /* INET6 */
+	    if (IN_MULTICAST(ti->ti_dst.s_addr))
+	      goto drop;
+#ifdef INET6
 	}
-
+#endif /* INET6 */
 	if (tiflags & TH_ACK)
-		tcp_respond(tp, mtod(m, caddr_t), m, (tcp_seq)0, th->th_ack,
-			TH_RST);
+		tcp_respond(tp, (caddr_t) ti, m, (tcp_seq)0, th->th_ack, TH_RST);
 	else {
 		if (tiflags & TH_SYN)
 			tlen++;
-		tcp_respond(tp, mtod(m, caddr_t), m, th->th_seq+tlen,
-			(tcp_seq)0, TH_RST|TH_ACK);
+		tcp_respond(tp, (caddr_t) ti, m, th->th_seq+tlen, (tcp_seq)0,
+		    TH_RST|TH_ACK);
 	}
 	/* destroy temporarily created socket */
 	if (dropsocket)
@@ -2143,8 +1997,14 @@ drop:
 	/*
 	 * Drop space held by incoming segment and return.
 	 */
-	if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
-		tcp_trace(TA_DROP, ostate, tp, tcp_savebuf, 0, tlen);
+	if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) {
+#ifdef INET6
+	  if (tp->pf == PF_INET6)
+	    tcp_trace(TA_DROP, ostate, tp, (caddr_t) &tcp_saveti6, 0, tlen);
+	  else
+#endif /* INET6 */
+	    tcp_trace(TA_DROP, ostate, tp, (caddr_t) &tcp_saveti, 0, tlen);
+	}
 
 	m_freem(m);
 	/* destroy temporarily created socket */
@@ -2154,22 +2014,17 @@ drop:
 #ifndef TUBA_INCLUDE
 }
 
-int
-tcp_dooptions(tp, cp, cnt, th, m, iphlen, ts_present, ts_val, ts_ecr)
+void
+tcp_dooptions(tp, cp, cnt, th, ts_present, ts_val, ts_ecr)
 	struct tcpcb *tp;
 	u_char *cp;
 	int cnt;
 	struct tcphdr *th;
-	struct mbuf *m;
-	int iphlen;
 	int *ts_present;
 	u_int32_t *ts_val, *ts_ecr;
 {
 	u_int16_t mss = 0;
 	int opt, optlen;
-#ifdef TCP_SIGNATURE
-	caddr_t sigp = NULL;
-#endif /* TCP_SIGNATURE */
 
 	for (; cnt > 0; cnt -= optlen, cp += optlen) {
 		opt = cp[0];
@@ -2238,137 +2093,11 @@ tcp_dooptions(tp, cp, cnt, th, m, iphlen, ts_present, ts_val, ts_ecr)
 				continue;
 			break;
 #endif          
-#ifdef TCP_SIGNATURE
-		case TCPOPT_SIGNATURE:
-			if (optlen != TCPOLEN_SIGNATURE)
-				continue;
-
-			if (sigp && bcmp(sigp, cp + 2, 16))
-				return -1;
-
-			sigp = cp + 2;
-			break;
-#endif /* TCP_SIGNATURE */
 		}
 	}
-
-#ifdef TCP_SIGNATURE
-	if ((sigp ? TF_SIGNATURE : 0) ^ (tp->t_flags & TF_SIGNATURE)) {
-		tcpstat.tcps_rcvbadsig++;
-		return -1;
-	}
-
-	if (sigp) {
-		MD5_CTX ctx;
-		union sockaddr_union sa;
-		struct tdb *tdb;
-		char sig[16];
-
-		memset(&sa, 0, sizeof(union sockaddr_union));
-
-		switch (tp->pf) {
-			case 0:
-			case AF_INET:
-				sa.sa.sa_len = sizeof(struct sockaddr_in);
-				sa.sa.sa_family = AF_INET;
-				sa.sin.sin_addr = tp->t_inpcb->inp_laddr;
-				break;
-#ifdef INET6
-			case AF_INET6:
-				sa.sa.sa_len = sizeof(struct sockaddr_in6);
-				sa.sa.sa_family = AF_INET6;
-				sa.sin6.sin6_addr = tp->t_inpcb->inp_laddr6;
-				break;
-#endif /* INET6 */
-		}
-
-		tdb = gettdb(0, &sa, IPPROTO_TCP);
-		if (tdb == NULL) {
-			printf("tdb miss\n");
-			tcpstat.tcps_rcvbadsig++;
-			return -1;
-		}
-
-		MD5Init(&ctx);
-
-		switch(tp->pf) {
-			case 0:
-#ifdef INET
-			case AF_INET:
-				{
-					struct ippseudo ippseudo;
-
-					ippseudo.ippseudo_src =
-						tp->t_inpcb->inp_faddr;
-					ippseudo.ippseudo_dst =
-						tp->t_inpcb->inp_laddr;
-					ippseudo.ippseudo_pad = 0;
-					ippseudo.ippseudo_p = IPPROTO_TCP;
-					ippseudo.ippseudo_len = htons(
-						m->m_pkthdr.len - iphlen);
-
-					MD5Update(&ctx, (char *)&ippseudo,
-						sizeof(struct ippseudo));
-				}
-				break;
-#endif /* INET */
-#ifdef INET6
-			case AF_INET6:
-				{
-					static int printed = 0;
-
-					if (!printed) {
-						printf("error: TCP MD5 support"
-							" for IPv6 not yet"
-							" implemented.\n");
-						printed = 1;
-					}
-				}
-				break
-#endif /* INET6 */
-		}
-
-		{
-			struct tcphdr tcphdr;
-
-			tcphdr.th_sport = th->th_sport;
-			tcphdr.th_dport = th->th_dport;
-			tcphdr.th_seq = htonl(th->th_seq);
-			tcphdr.th_ack = htonl(th->th_ack);
-			tcphdr.th_off = th->th_off;
-			tcphdr.th_x2 = th->th_x2;
-			tcphdr.th_flags = th->th_flags;
-			tcphdr.th_win = htons(th->th_win);
-			tcphdr.th_sum = 0;
-			tcphdr.th_urp = htons(th->th_urp);
-
-			MD5Update(&ctx, (char *)&tcphdr,
-				sizeof(struct tcphdr));
-		}
-
-		if (m_apply(m, iphlen + th->th_off * sizeof(uint32_t),
-				m->m_pkthdr.len - (iphlen + th->th_off *
-				sizeof(uint32_t)), tcp_signature_apply,
-				(caddr_t)&ctx))
-			return (-1); 
-
-		MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen);
-		MD5Final(sig, &ctx);
-
-		if (bcmp(sig, sigp, 16)) {
-			tcpstat.tcps_rcvbadsig++;
-			return (-1);
-		}
-
-		tcpstat.tcps_rcvgoodsig++;
-	};
-#endif /* TCP_SIGNATURE */
-
 	/* Update t_maxopd and t_maxseg after all options are processed */
 	if (th->th_flags & TH_SYN)
 		(void) tcp_mss(tp, mss);	/* sets t_maxseg */
-
-	return (0);
 }
 
 #if defined(TCP_SACK) || defined(TCP_NEWRENO)