Significant cleanups in the way TCP is made to handle multiple network

protocols.

"struct tcpiphdr" is now gone from much of the code, as are separate pointers
for ti and ti6. The result is fewer variables, which is generally a good thing.

Simple if(is_ipv6) ... else ... tests are gone in favor of a
switch(protocol family), which allows future new protocols to be added easily.
This also makes it possible for someone so inclined to re-implement TUBA (TCP
over CLNP?) and do it right instead of the kluged way it was done in 4.4.

The TCP header template is now referenced through a mbuf rather than done
through a data pointer and dtom()ed as needed. This is partly because dtom() is
evil and partly because max_linkhdr + IPv6 + TCP + MSS/TS/SACK opts won't fit
inside a packet header mbuf, so we need to grab a cluster for that (which the
code now does, if needed).

1 files changed, 23 insertions, 5 deletions

diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
index 38e82edc26c..de6ee75474f 100644
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcp_usrreq.c,v 1.33 1999/03/24 02:28:21 cmetz Exp $	*/
+/*	$OpenBSD: tcp_usrreq.c,v 1.34 1999/07/02 20:39:08 cmetz Exp $	*/
 /*	$NetBSD: tcp_usrreq.c,v 1.20 1996/02/13 23:44:16 christos Exp $	*/
 
 /*
@@ -466,7 +466,7 @@ tcp_usrreq(so, req, m, nam, control)
 		panic("tcp_usrreq");
 	}
 	if (tp && (so->so_options & SO_DEBUG))
-		tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req, 0);
+		tcp_trace(TA_USER, ostate, tp, (caddr_t)0, req, 0);
 	splx(s);
 	return (error);
 }
@@ -531,7 +531,13 @@ tcp_ctloutput(op, so, level, optname, mp)
 			break;
 
 		case TCP_MAXSEG:
-			if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg)
+			if (m == NULL || m->m_len < sizeof (int)) {
+				error = EINVAL;
+				break;
+			}
+
+			i = *mtod(m, int *);
+			if (i > 0 && i <= tp->t_maxseg)
 				tp->t_maxseg = i;
 			else
 				error = EINVAL;
@@ -539,8 +545,20 @@ tcp_ctloutput(op, so, level, optname, mp)
 
 #ifdef TCP_SACK
 		case TCP_SACK_DISABLE:
-			i = *mtod(m, int *);
-			tp->sack_disable = i;
+			if (m == NULL || m->m_len < sizeof (int)) {
+				error = EINVAL;
+				break;
+			}
+
+			if (TCPS_HAVEESTABLISHED(tp->t_state)) {
+				error = EPERM;
+				break;
+			}
+
+			if (*mtod(m, int *))
+				tp->sack_disable = 1;
+			else
+				tp->sack_disable = 0;
 			break;
 #endif
 		default: