[PATCH v2] net: provide default_advmss() methods to blackhole dst_ops

[Eric Dumazet <eric.dumazet@gmail.com>]

Le vendredi 18 février 2011 à 14:33 +0100, Eric Dumazet a écrit :

> I had this exact idea but found we need struct net pointer to get this
> value, not provided in parameters, so I falled back to the 256 value.
> 
> 

Hmm, reading again this stuff, maybe we can just use
ipv4_default_advmss() instead of a custom one.

dst->dev should be available

[PATCH] net: provide default_advmss() methods to blackhole dst_ops

Commit 0dbaee3b37e118a (net: Abstract default ADVMSS behind an
accessor.) introduced a possible crash in tcp_connect_init(), when
dst->default_advmss() is called from dst_metric_advmss()

Reported-by: George Spelvin <linux@horizon.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Roland Dreier <roland@purestorage.com>
CC: Changli Gao <xiaosuo@gmail.com>
CC: Daniel Baluta <dbaluta@ixiacom.com>
---
 net/ipv4/route.c |    1 +
 net/ipv6/route.c |    1 +
 2 files changed, 2 insertions(+)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 788a3e7..6ed6603 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2722,6 +2722,7 @@ static struct dst_ops ipv4_dst_blackhole_ops = {
 	.destroy		=	ipv4_dst_destroy,
 	.check			=	ipv4_blackhole_dst_check,
 	.default_mtu		=	ipv4_blackhole_default_mtu,
+	.default_advmss		=	ipv4_default_advmss,
 	.update_pmtu		=	ipv4_rt_blackhole_update_pmtu,
 };
 
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 1c29f95..a998db6 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -128,6 +128,7 @@ static struct dst_ops ip6_dst_blackhole_ops = {
 	.destroy		=	ip6_dst_destroy,
 	.check			=	ip6_dst_check,
 	.default_mtu		=	ip6_blackhole_default_mtu,
+	.default_advmss		=	ip6_default_advmss,
 	.update_pmtu		=	ip6_rt_blackhole_update_pmtu,
 };