sctp: Fix to start T5-shutdown-guard timer while enter SHUTDOWN-SENT state

RFC 4960: Section 9.2
The sender of the SHUTDOWN MAY also start an overall guard timer
'T5-shutdown-guard' to bound the overall time for the shutdown
sequence.  At the expiration of this timer, the sender SHOULD abort
the association by sending an ABORT chunk.  If the 'T5-shutdown-
guard' timer is used, it SHOULD be set to the recommended value of 5
times 'RTO.Max'.

The timer 'T5-shutdown-guard' is used to counter the overall time
for shutdown sequence, and it's start by the sender of the SHUTDOWN.
So timer 'T5-shutdown-guard' should be start when we send the first
SHUTDOWN chunk and enter the SHUTDOWN-SENT state, not start when we
receipt of the SHUTDOWN primitive and enter SHUTDOWN-PENDING state.

If 'T5-shutdown-guard' timer is start at SHUTDOWN-PENDING state, the
association may be ABORT while data is still transmitting.

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

2 files changed, 8 insertions, 18 deletions

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 7c622af2ce55..e57d1d3ad0a6 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -2076,10 +2076,6 @@ sctp_disposition_t sctp_sf_shutdown_pending_abort(
                     sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
                 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
 
-        /* Stop the T5-shutdown guard timer.  */
-        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
-                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
-
         return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands);
 }
 
@@ -4543,13 +4539,6 @@ sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
                         SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
 
-        /* sctpimpguide-05 Section 2.12.2
-         * The sender of the SHUTDOWN MAY also start an overall guard timer
-         * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
-         */
-        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
-                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
-
         disposition = SCTP_DISPOSITION_CONSUME;
         if (sctp_outq_is_empty(&asoc->outqueue)) {
                 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
@@ -4994,6 +4983,13 @@ sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
 
+        /* RFC 4960 Section 9.2
+         * The sender of the SHUTDOWN MAY also start an overall guard timer
+         * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
+         */
+        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
+                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
+
         if (asoc->autoclose)
                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
                                 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
@@ -5520,12 +5516,6 @@ sctp_disposition_t sctp_sf_autoclose_timer_expire(
         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
                         SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
 
-        /* sctpimpguide-05 Section 2.12.2
-         * The sender of the SHUTDOWN MAY also start an overall guard timer
-         * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
-         */
-        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
-                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
         disposition = SCTP_DISPOSITION_CONSUME;
         if (sctp_outq_is_empty(&asoc->outqueue)) {
                 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type,
diff --git a/net/sctp/sm_statetable.c b/net/sctp/sm_statetable.c
index d991237fb400..dd4ddc40c0ad 100644
--- a/net/sctp/sm_statetable.c
+++ b/net/sctp/sm_statetable.c
@@ -897,7 +897,7 @@ static const sctp_sm_table_entry_t other_event_table[SCTP_NUM_OTHER_TYPES][SCTP_
         /* SCTP_STATE_ESTABLISHED */ \
         TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
         /* SCTP_STATE_SHUTDOWN_PENDING */ \
-        TYPE_SCTP_FUNC(sctp_sf_t5_timer_expire), \
+        TYPE_SCTP_FUNC(sctp_sf_timer_ignore), \
         /* SCTP_STATE_SHUTDOWN_SENT */ \
         TYPE_SCTP_FUNC(sctp_sf_t5_timer_expire), \
         /* SCTP_STATE_SHUTDOWN_RECEIVED */ \