svn commit: r184722 - head/sys/netinet
Bjoern A. Zeeb
bz at FreeBSD.org
Thu Nov 6 05:26:00 PST 2008
Author: bz
Date: Thu Nov 6 13:25:59 2008
New Revision: 184722
URL: http://svn.freebsd.org/changeset/base/184722
Log:
Fix a bug introduced with r182851 splitting tcp_mss() into
tcp_mss() and tcp_mss_update() so that tcp_mtudisc() could
re-use the same code.
Move the TSO logic back to tcp_mss() and out of tcp_mss_update().
We tried to avoid that initially but if were are called from
tcp_output() with EMSGSIZE, we cleared the TSO flag on the tcpcb
there, called into tcp_mtudisc() and tcp_mss_update() which
then would reenable TSO on the tcpcb based on TSO capabilities
of the interface as learnt in tcp_maxmtu/6().
So if TSO was enabled on the (possibly new) outgoing interface
it was turned back on, which lead to an endless loop between
tcp_output() and tcp_mtudisc() until we overflew the stack.
Reported by: kmacy
MFC after: 2 months (along with r182851)
Modified:
head/sys/netinet/tcp_input.c
head/sys/netinet/tcp_subr.c
head/sys/netinet/tcp_var.h
Modified: head/sys/netinet/tcp_input.c
==============================================================================
--- head/sys/netinet/tcp_input.c Thu Nov 6 12:59:00 2008 (r184721)
+++ head/sys/netinet/tcp_input.c Thu Nov 6 13:25:59 2008 (r184722)
@@ -2812,7 +2812,8 @@ tcp_xmit_timer(struct tcpcb *tp, int rtt
* segment. Outgoing SYN/ACK MSS settings are handled in tcp_mssopt().
*/
void
-tcp_mss_update(struct tcpcb *tp, int offer, struct hc_metrics_lite *metricptr)
+tcp_mss_update(struct tcpcb *tp, int offer,
+ struct hc_metrics_lite *metricptr, int *mtuflags)
{
INIT_VNET_INET(tp->t_inpcb->inp_vnet);
int mss;
@@ -2820,7 +2821,6 @@ tcp_mss_update(struct tcpcb *tp, int off
struct inpcb *inp = tp->t_inpcb;
struct hc_metrics_lite metrics;
int origoffer = offer;
- int mtuflags = 0;
#ifdef INET6
int isipv6 = ((inp->inp_vflag & INP_IPV6) != 0) ? 1 : 0;
size_t min_protoh = isipv6 ?
@@ -2835,12 +2835,12 @@ tcp_mss_update(struct tcpcb *tp, int off
/* Initialize. */
#ifdef INET6
if (isipv6) {
- maxmtu = tcp_maxmtu6(&inp->inp_inc, &mtuflags);
+ maxmtu = tcp_maxmtu6(&inp->inp_inc, mtuflags);
tp->t_maxopd = tp->t_maxseg = V_tcp_v6mssdflt;
} else
#endif
{
- maxmtu = tcp_maxmtu(&inp->inp_inc, &mtuflags);
+ maxmtu = tcp_maxmtu(&inp->inp_inc, mtuflags);
tp->t_maxopd = tp->t_maxseg = V_tcp_mssdflt;
}
@@ -2858,10 +2858,6 @@ tcp_mss_update(struct tcpcb *tp, int off
return;
}
- /* Check the interface for TSO capabilities. */
- if (mtuflags & CSUM_TSO)
- tp->t_flags |= TF_TSO;
-
/* What have we got? */
switch (offer) {
case 0:
@@ -2980,12 +2976,13 @@ tcp_mss(struct tcpcb *tp, int offer)
struct inpcb *inp;
struct socket *so;
struct hc_metrics_lite metrics;
+ int mtuflags = 0;
#ifdef INET6
int isipv6;
#endif
KASSERT(tp != NULL, ("%s: tp == NULL", __func__));
- tcp_mss_update(tp, offer, &metrics);
+ tcp_mss_update(tp, offer, &metrics, &mtuflags);
mss = tp->t_maxseg;
inp = tp->t_inpcb;
@@ -3098,6 +3095,10 @@ tcp_mss(struct tcpcb *tp, int offer)
tp->snd_cwnd = mss * V_ss_fltsz_local;
else
tp->snd_cwnd = mss * V_ss_fltsz;
+
+ /* Check the interface for TSO capabilities. */
+ if (mtuflags & CSUM_TSO)
+ tp->t_flags |= TF_TSO;
}
/*
Modified: head/sys/netinet/tcp_subr.c
==============================================================================
--- head/sys/netinet/tcp_subr.c Thu Nov 6 12:59:00 2008 (r184721)
+++ head/sys/netinet/tcp_subr.c Thu Nov 6 13:25:59 2008 (r184722)
@@ -1562,7 +1562,7 @@ tcp_mtudisc(struct inpcb *inp, int errno
tp = intotcpcb(inp);
KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
- tcp_mss_update(tp, -1, NULL);
+ tcp_mss_update(tp, -1, NULL, NULL);
so = inp->inp_socket;
SOCKBUF_LOCK(&so->so_snd);
Modified: head/sys/netinet/tcp_var.h
==============================================================================
--- head/sys/netinet/tcp_var.h Thu Nov 6 12:59:00 2008 (r184721)
+++ head/sys/netinet/tcp_var.h Thu Nov 6 13:25:59 2008 (r184722)
@@ -546,7 +546,7 @@ void tcp_reass_init(void);
void tcp_input(struct mbuf *, int);
u_long tcp_maxmtu(struct in_conninfo *, int *);
u_long tcp_maxmtu6(struct in_conninfo *, int *);
-void tcp_mss_update(struct tcpcb *, int, struct hc_metrics_lite *);
+void tcp_mss_update(struct tcpcb *, int, struct hc_metrics_lite *, int *);
void tcp_mss(struct tcpcb *, int);
int tcp_mssopt(struct in_conninfo *);
struct inpcb *
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