sctp: check cached dst before using it

BugLink: http://bugs.launchpad.net/bugs/1013748

[ Upstream commit e0268868ba064980488fc8c194db3d8e9fb2959c ]

dst_check() will take care of SA (and obsolete field), hence
IPsec rekeying scenario is taken into account.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Vlad Yaseivch <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index b2c2366676a..f686066087d 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -700,4 +700,17 @@ static inline void sctp_v4_map_v6(union sctp_addr *addr)
         addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
 }
 
+/* The cookie is always 0 since this is how it's used in the
+ * pmtu code.
+ */
+static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
+{
+        if (t->dst && !dst_check(t->dst, 0)) {
+                dst_release(t->dst);
+                t->dst = NULL;
+        }
+
+        return t->dst;
+}
+
 #endif /* __net_sctp_h__ */