sctp: fix to choose alternate destination when retransmit ASCONF chunk

RFC 5061 Section 5.1 ASCONF Chunk Procedures said:

B4)  Re-transmit the ASCONF Chunk last sent and if possible choose an
     alternate destination address (please refer to [RFC4960],
     Section 6.4.1).  An endpoint MUST NOT add new parameters to this
     chunk; it MUST be the same (including its Sequence Number) as
     the last ASCONF sent.  An endpoint MAY, however, bundle an
     additional ASCONF with new ASCONF parameters with the next
     Sequence Number.  For details, see Section 5.5.

This patch fix to choose an alternate destination address when
re-transmit the ASCONF chunk, with some dup codes cleanup.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index e2020eb2c8ca..86426aac1600 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -686,7 +686,8 @@ static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds,
 {
         struct sctp_transport *t;
 
-        t = sctp_assoc_choose_shutdown_transport(asoc);
+        t = sctp_assoc_choose_alter_transport(asoc,
+                                              asoc->shutdown_last_sent_to);
         asoc->shutdown_last_sent_to = t;
         asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto;
         chunk->transport = t;
@@ -777,7 +778,7 @@ static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds,
 {
         struct sctp_transport *t;
 
-        t = asoc->peer.active_path;
+        t = sctp_assoc_choose_alter_transport(asoc, chunk->transport);
         asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto;
         chunk->transport = t;
 }
@@ -1379,7 +1380,8 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
 
                 case SCTP_CMD_INIT_CHOOSE_TRANSPORT:
                         chunk = cmd->obj.ptr;
-                        t = sctp_assoc_choose_init_transport(asoc);
+                        t = sctp_assoc_choose_alter_transport(asoc,
+                                                asoc->init_last_sent_to);
                         asoc->init_last_sent_to = t;
                         chunk->transport = t;
                         t->init_sent_count++;