From a4d69a4c3ca6be699ed8cdc4683381ce44b85c90 Mon Sep 17 00:00:00 2001 From: Xin Long 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should check if transport pmtu is dst mtu Now when sending a packet, sctp_transport_dst_check will check if dst is obsolete by calling ipv4/ip6_dst_check.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 Signed-off-by: David S. Miller --- 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 6dfc5536a3e6..1f71ee5ab518 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;