- Consistently update snd_wl1, snd_wl2, and rcv_up in the header

   prediction code.  Previously, 2GB worth of header predicted data
   could leave these variables too far out of sequence which would cause
   problems after receiving a packet that did not match the header
   prediction.

Submitted by:	Bill Baumann <bbaumann@isilon.com>
Sponsored by:	Isilon Systems, Inc.
Reviewed by:	hsu, pete@isilon.com, neal@isilon.com, aaronp@isilon.com

sys/netinet/tcp_input.c

@@ -1027,7 +1027,11 @@ tcp_input(m, off0)
 				tcpstat.tcps_rcvackpack++;
 				tcpstat.tcps_rcvackbyte += acked;
 				sbdrop(&so->so_snd, acked);
-				tp->snd_una = th->th_ack;
+				/*
+				 * pull snd_wl2 up to prevent seq wrap relative
+				 * to th_ack.
+				 */
+				tp->snd_wl2 = tp->snd_una = th->th_ack;
 				tp->t_dupacks = 0;
 				m_freem(m);
 				ND6_HINT(tp); /* some progress has been done */
@@ -1067,6 +1071,16 @@ tcp_input(m, off0)
 			 */
 			++tcpstat.tcps_preddat;
 			tp->rcv_nxt += tlen;
+			/*
+			 * Pull snd_wl1 up to prevent seq wrap relative to
+			 * th_seq.
+			 */
+			tp->snd_wl1 = th->th_seq;
+			/*
+			 * Pull rcv_up up to prevent seq wrap relative to
+			 * rcv_nxt.
+			 */
+			tp->rcv_up = tp->rcv_nxt;
 			tcpstat.tcps_rcvpack++;
 			tcpstat.tcps_rcvbyte += tlen;
 			ND6_HINT(tp);	/* some progress has been done */

sys/netinet/tcp_reass.c

@@ -1027,7 +1027,11 @@ tcp_input(m, off0)
 				tcpstat.tcps_rcvackpack++;
 				tcpstat.tcps_rcvackbyte += acked;
 				sbdrop(&so->so_snd, acked);
-				tp->snd_una = th->th_ack;
+				/*
+				 * pull snd_wl2 up to prevent seq wrap relative
+				 * to th_ack.
+				 */
+				tp->snd_wl2 = tp->snd_una = th->th_ack;
 				tp->t_dupacks = 0;
 				m_freem(m);
 				ND6_HINT(tp); /* some progress has been done */
@@ -1067,6 +1071,16 @@ tcp_input(m, off0)
 			 */
 			++tcpstat.tcps_preddat;
 			tp->rcv_nxt += tlen;
+			/*
+			 * Pull snd_wl1 up to prevent seq wrap relative to
+			 * th_seq.
+			 */
+			tp->snd_wl1 = th->th_seq;
+			/*
+			 * Pull rcv_up up to prevent seq wrap relative to
+			 * rcv_nxt.
+			 */
+			tp->rcv_up = tp->rcv_nxt;
 			tcpstat.tcps_rcvpack++;
 			tcpstat.tcps_rcvbyte += tlen;
 			ND6_HINT(tp);	/* some progress has been done */