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>
 {
        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. */