svn commit: r184864 - user/kmacy/HEAD_fast_multi_xmit/sys/netinet

[Kip Macy]

Author: kmacy
Date: Wed Nov 12 07:32:07 2008
New Revision: 184864
URL: http://svn.freebsd.org/changeset/base/184864

Log:
  Work around possible infinite recursion in tcp_mtudisc, allowing tcp_output
  to be called even if maxopd is smaller than mss

Modified:
  user/kmacy/HEAD_fast_multi_xmit/sys/netinet/tcp_subr.c
  user/kmacy/HEAD_fast_multi_xmit/sys/netinet/tcp_var.h

Modified: user/kmacy/HEAD_fast_multi_xmit/sys/netinet/tcp_subr.c
==============================================================================
--- user/kmacy/HEAD_fast_multi_xmit/sys/netinet/tcp_subr.c	Wed Nov 12 07:16:23 2008	(r184863)
+++ user/kmacy/HEAD_fast_multi_xmit/sys/netinet/tcp_subr.c	Wed Nov 12 07:32:07 2008	(r184864)
@@ -1579,9 +1579,13 @@ tcp_mtudisc(struct inpcb *inp, int errno
 	tp->snd_recover = tp->snd_max;
 	if (tp->t_flags & TF_SACK_PERMIT)
 		EXIT_FASTRECOVERY(tp);
-	if (tp->t_maxopd <= mss)
-		return (inp);	
-	tcp_output_send(tp);
+
+	if ((tp->t_flags & TF_RECURSE) == 0) {
+		tp->t_flags |= TF_RECURSE;
+		tcp_output_send(tp);
+		tp->t_flags &= ~TF_RECURSE;
+	}
+
 	return (inp);
 }
 

Modified: user/kmacy/HEAD_fast_multi_xmit/sys/netinet/tcp_var.h
==============================================================================
--- user/kmacy/HEAD_fast_multi_xmit/sys/netinet/tcp_var.h	Wed Nov 12 07:16:23 2008	(r184863)
+++ user/kmacy/HEAD_fast_multi_xmit/sys/netinet/tcp_var.h	Wed Nov 12 07:32:07 2008	(r184864)
@@ -127,7 +127,8 @@ struct tcpcb {
 #define	TF_ECN_PERMIT	0x4000000	/* connection ECN-ready */
 #define	TF_ECN_SND_CWR	0x8000000	/* ECN CWR in queue */
 #define	TF_ECN_SND_ECE	0x10000000	/* ECN ECE in queue */
-
+#define	TF_RECURSE	0x20000000	/* potentially recursing in tcp_output */
+	
 	tcp_seq	snd_una;		/* send unacknowledged */
 	tcp_seq	snd_max;		/* highest sequence number sent;
 					 * used to recognize retransmits