[SCTP] Flag a pmtu change request

Currently, if the socket is owned by the user, we drop the ICMP
message.  As a result SCTP forgets that path MTU changed and
never adjusting it's estimate.  This causes all subsequent
packets to be fragmented.  With this patch, we'll flag the association
that it needs to udpate it's estimate based on the already updated
routing information.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: Sridhar Samudrala <sri@us.ibm.com>
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index dda72bf..16baef4 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -503,6 +503,13 @@
 	return frag;
 }
 
+static inline void sctp_assoc_pending_pmtu(struct sctp_association *asoc)
+{
+
+	sctp_assoc_sync_pmtu(asoc);
+	asoc->pmtu_pending = 0;
+}
+
 /* Walk through a list of TLV parameters.  Don't trust the
  * individual parameter lengths and instead depend on
  * the chunk length to indicate when to stop.  Make sure