[PATCH] sctp: fix the check for path failure detection

[Chunbo Luo]

The transport is marked DOWN immediately after sending the max+1 HB,
which is equal to not sending the max+1 HB at all. We should wait
a next period and make sure the last HB is not acknowledged.

Signed-off-by: Chunbo Luo <chunbo.luo@xxxxxxxxxxxxx>
---
 include/net/sctp/command.h |    1 +
 net/sctp/sm_sideeffect.c   |   39 ++++++++++++++++++++++++++++-----------
 net/sctp/sm_statefuns.c    |   16 ++++++++++++++--
 3 files changed, 43 insertions(+), 13 deletions(-)

diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
index 3b96680..256effd 100644
--- a/include/net/sctp/command.h
+++ b/include/net/sctp/command.h
@@ -77,6 +77,7 @@ typedef enum {
 	SCTP_CMD_HB_TIMERS_START,    /* Start the heartbeat timers. */
 	SCTP_CMD_HB_TIMER_UPDATE,    /* Update a heartbeat timers.  */
 	SCTP_CMD_HB_TIMERS_STOP,     /* Stop the heartbeat timers.  */
+	SCTP_CMD_PATH_FAILURE_DETECTION,/* Path failure detection. */
 	SCTP_CMD_TRANSPORT_HB_SENT,  /* Reset the status of a transport. */
 	SCTP_CMD_TRANSPORT_IDLE,     /* Do manipulations on idle transport */
 	SCTP_CMD_TRANSPORT_ON,       /* Mark the transport as active. */
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 86426aa..db299c6 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -432,7 +432,25 @@ sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = {
  * mark the destination transport address as inactive, and a
  * notification SHOULD be sent to the upper layer.
  *
+ * transport error counter is incremented in sctp_do_8_2_transport_strike
  */
+static void sctp_cmd_path_failure_detection(struct sctp_association *asoc,
+					   struct sctp_transport *transport)
+{
+	if (transport->error_count > transport->pathmaxrxt) {
+		SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
+					 " transport IP: port:%d failed.\n",
+					 asoc,
+					 (&transport->ipaddr),
+					 ntohs(transport->ipaddr.v4.sin_port));
+		sctp_assoc_control_transport(asoc, transport,
+					     SCTP_TRANSPORT_DOWN,
+					     SCTP_FAILED_THRESHOLD);
+	}
+}
+
+
+ /*  Mark a strike against a transport */
 static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
 					 struct sctp_transport *transport,
 					 int is_hb)
@@ -446,17 +464,11 @@ static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
 	if (transport->state != SCTP_UNCONFIRMED)
 		asoc->overall_error_count++;
 
-	if (transport->state != SCTP_INACTIVE &&
-	    (transport->error_count++ >= transport->pathmaxrxt)) {
-		SCTP_DEBUG_PRINTK_IPADDR("transport_strike:association %p",
-					 " transport IP: port:%d failed.\n",
-					 asoc,
-					 (&transport->ipaddr),
-					 ntohs(transport->ipaddr.v4.sin_port));
-		sctp_assoc_control_transport(asoc, transport,
-					     SCTP_TRANSPORT_DOWN,
-					     SCTP_FAILED_THRESHOLD);
-	}
+	/* The check for transport's error counter exceeding the threshold
+	 * is done in the state function.
+	 */
+	if (transport->state != SCTP_INACTIVE)
+		transport->error_count++;
 
 	/* E2) For the destination address for which the timer
 	 * expires, set RTO <- RTO * 2 ("back off the timer").  The
@@ -1464,6 +1476,11 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
 						    0);
 			break;
 
+		case SCTP_CMD_PATH_FAILURE_DETECTION:
+			t = cmd->obj.transport;
+			sctp_cmd_path_failure_detection(asoc, t);
+			break;
+
 		case SCTP_CMD_TRANSPORT_IDLE:
 			t = cmd->obj.transport;
 			sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE);
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 7288192..f4c05fd 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -981,6 +981,9 @@ sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep,
 	 */
 
 	if (transport->param_flags & SPP_HB_ENABLE) {
+		/* Do the path failure detection before send beat */
+		sctp_add_cmd_sf(commands, SCTP_CMD_PATH_FAILURE_DETECTION,
+				SCTP_TRANSPORT(transport));
 		if (SCTP_DISPOSITION_NOMEM ==
 				sctp_sf_heartbeat(ep, asoc, type, arg,
 						  commands))
@@ -5229,6 +5232,8 @@ sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep,
 	 */
 
 	/* Do some failure management (Section 8.2). */
+	sctp_add_cmd_sf(commands, SCTP_CMD_PATH_FAILURE_DETECTION,
+			SCTP_TRANSPORT(transport));
 	sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
 
 	/* NB: Rules E4 and F1 are implicit in R1.  */
@@ -5436,9 +5441,13 @@ sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep,
 	 * If we remove the transport an SHUTDOWN was last sent to, don't
 	 * do failure management.
 	 */
-	if (asoc->shutdown_last_sent_to)
+	if (asoc->shutdown_last_sent_to) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_PATH_FAILURE_DETECTION,
+				SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
+
 		sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
 				SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
+	}
 
 	/* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
 	 * the T2-shutdown timer.
@@ -5475,9 +5484,12 @@ sctp_disposition_t sctp_sf_t4_timer_expire(
 	 * detection on the appropriate destination address as defined in
 	 * RFC2960 [5] section 8.1 and 8.2.
 	 */
-	if (transport)
+	if (transport) {
+		sctp_add_cmd_sf(commands, SCTP_CMD_PATH_FAILURE_DETECTION,
+				SCTP_TRANSPORT(transport));
 		sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
 				SCTP_TRANSPORT(transport));
+	}
 
 	/* Reconfig T4 timer and transport. */
 	sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
-- 
1.6.0.3

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