Commit a4d69a4c authored Feb 17, 2017 by Xin Long Committed by David S. Miller Feb 19, 2017

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is obsolete by calling ipv4/ip6_dst_check.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>

parent 585396bc

include/net/sctp/sctp.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -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;