sctp: send SHUTDOWN-ACK chunk back to the source.

SHUTDOWN-ACK is alaways sent to the primary path at the first time,
but should better transmit SHUTDOWN-ACK chunk to the same destination
transport address from which it received the SHUTDOWN chunk.
Based on the work from Wei Yongjun <yjwei@cn.fujitsu.com>.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 4c5bed9af4e3..49fb9acece63 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -697,11 +697,15 @@ static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 {
         struct sctp_transport *t;
 
-        t = sctp_assoc_choose_alter_transport(asoc,
+        if (chunk->transport)
+                t = chunk->transport;
+        else {
+                t = sctp_assoc_choose_alter_transport(asoc,
                                               asoc->shutdown_last_sent_to);
+                chunk->transport = t;
+        }
         asoc->shutdown_last_sent_to = t;
         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
-        chunk->transport = t;
 }
 
 /* Helper function to change the state of an association. */