sctp: check src addr when processing SACK to update transport state

Suppose we have an SCTP connection with two paths. After connection is
established, path1 is not available, thus this path is marked as inactive. Then
traffic goes through path2, but for some reasons packets are delayed (after
rto.max). Because packets are delayed, the retransmit mechanism will switch
again to path1. At this time, we receive a delayed SACK from path2. When we
update the state of the path in sctp_check_transmitted(), we do not take into
account the source address of the SACK, hence we update the wrong path.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index bcfebb9..57f7de8 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -752,11 +752,11 @@
 /* Helper function to process the process SACK command.  */
 static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds,
 				 struct sctp_association *asoc,
-				 struct sctp_sackhdr *sackh)
+				 struct sctp_chunk *chunk)
 {
 	int err = 0;
 
-	if (sctp_outq_sack(&asoc->outqueue, sackh)) {
+	if (sctp_outq_sack(&asoc->outqueue, chunk)) {
 		struct net *net = sock_net(asoc->base.sk);
 
 		/* There are no more TSNs awaiting SACK.  */