From a4d69a4c3ca6be699ed8cdc4683381ce44b85c90 Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Fri, 17 Feb 2017 16:41:45 +0800
Subject: [PATCH] sctp: sctp_transport_dst_check should check if transport pmtu
is dst mtu
Now when sending a packet, sctp_transport_dst_check will check if dst
is obsolete by calling ipv4/ip6_dst_check. But they return obsolete
only when adding a new cache, after that when the cache's pmtu is
updated again, it will not trigger transport->dst/pmtu's update.
It can be reproduced by reducing route's pmtu twice. At the 1st time
client will add a new cache, and transport->pathmtu gets updated as
sctp_transport_dst_check finds it's obsolete. But at the 2nd time,
cache's mtu is updated, sctp client will never send out any packet,
because transport->pmtu has no chance to update.
This patch is to fix this by also checking if transport pmtu is dst
mtu in sctp_transport_dst_check, so that transport->pmtu can be
updated on time.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/sctp/sctp.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 6dfc5536a3e65..1f71ee5ab5184 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -596,7 +596,9 @@ static inline void sctp_v4_map_v6(union sctp_addr *addr)
*/
static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
{
- if (t->dst && !dst_check(t->dst, t->dst_cookie))
+ if (t->dst && (!dst_check(t->dst, t->dst_cookie) ||
+ t->pathmtu != max_t(size_t, SCTP_TRUNC4(dst_mtu(t->dst)),
+ SCTP_DEFAULT_MINSEGMENT)))
sctp_transport_dst_release(t);
return t->dst;