[SCTP] Fix issues with handling stale cookie error over multihoming

associations.
Signed-off-by: Jorge Hernandez <jhh@lucent.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>

include/net/sctp/command.h

@@ -94,6 +94,9 @@ typedef enum {
 	SCTP_CMD_REPORT_FWDTSN,	 /* Report new cumulative TSN Ack. */
 	SCTP_CMD_PROCESS_FWDTSN, /* Skips were reported, so process further. */
 	SCTP_CMD_CLEAR_INIT_TAG, /* Clears association peer's inittag. */
+	SCTP_CMD_DEL_NON_PRIMARY, /* Removes non-primary peer transports. */
+	SCTP_CMD_T3_RTX_TIMERS_STOP, /* Stops T3-rtx pending timers */
+	SCTP_CMD_FORCE_PRIM_RETRAN,  /* Forces retrans. over primary path. */
 	SCTP_CMD_LAST
 } sctp_verb_t;
 

net/sctp/sm_sideeffect.c

@@ -529,6 +529,23 @@ static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds,
 	}
 }
 
+/* Helper function to stop any pending T3-RTX timers */
+static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds,
+				        struct sctp_association *asoc)
+{
+	struct sctp_transport *t;
+	struct list_head *pos;
+
+	list_for_each(pos, &asoc->peer.transport_addr_list) {
+		t = list_entry(pos, struct sctp_transport, transports);
+		if (timer_pending(&t->T3_rtx_timer) &&
+		    del_timer(&t->T3_rtx_timer)) {
+			sctp_transport_put(t);
+		}
+	}
+}
+
+
 /* Helper function to update the heartbeat timer. */
 static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds,
 				     struct sctp_association *asoc,
@@ -749,6 +766,26 @@ static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq,
 	return;
 }
 
+/* Helper function to remove the association non-primary peer 
+ * transports.
+ */ 
+static void sctp_cmd_del_non_primary(struct sctp_association *asoc)
+{
+	struct sctp_transport *t;
+	struct list_head *pos;
+	struct list_head *temp;
+
+	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
+		t = list_entry(pos, struct sctp_transport, transports);
+		if (!sctp_cmp_addr_exact(&t->ipaddr,
+		                         &asoc->peer.primary_addr)) {
+			sctp_assoc_del_peer(asoc, &t->ipaddr);
+		}
+	}
+
+	return;
+}
+
 /* These three macros allow us to pull the debugging code out of the
  * main flow of sctp_do_sm() to keep attention focused on the real
  * functionality there.
@@ -1048,6 +1085,27 @@ int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 			if (cmd->obj.ptr)
 				sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
 						SCTP_CHUNK(cmd->obj.ptr));
+
+			/* FIXME - Eventually come up with a cleaner way to
+			 * enabling COOKIE-ECHO + DATA bundling during 
+			 * multihoming stale cookie scenarios, the following 
+			 * command plays with asoc->peer.retran_path to 
+			 * avoid the problem of sending the COOKIE-ECHO and 
+			 * DATA in different paths, which could result 
+			 * in the association being ABORTed if the DATA chunk 
+			 * is processed first by the server.  Checking the
+			 * init error counter simply causes this command
+			 * to be executed only during failed attempts of
+			 * association establishment.
+			 */
+			if ((asoc->peer.retran_path != 
+			     asoc->peer.primary_path) && 
+			    (asoc->counters[SCTP_COUNTER_INIT_ERROR] > 0)) {
+				sctp_add_cmd_sf(commands, 
+				                SCTP_CMD_FORCE_PRIM_RETRAN,
+						SCTP_NULL());
+			}
+
 			break;
 
 		case SCTP_CMD_GEN_SHUTDOWN:
@@ -1282,6 +1340,19 @@ int sctp_cmd_interpreter(sctp_event_t event_type, sctp_subtype_t subtype,
 		case SCTP_CMD_CLEAR_INIT_TAG:
 			asoc->peer.i.init_tag = 0;
 			break;
+		case SCTP_CMD_DEL_NON_PRIMARY:
+			sctp_cmd_del_non_primary(asoc);
+			break;
+		case SCTP_CMD_T3_RTX_TIMERS_STOP:
+			sctp_cmd_t3_rtx_timers_stop(commands, asoc);
+			break;
+		case SCTP_CMD_FORCE_PRIM_RETRAN:
+			t = asoc->peer.retran_path;
+			asoc->peer.retran_path = asoc->peer.primary_path;
+			error = sctp_outq_uncork(&asoc->outqueue);
+			local_cork = 0;
+			asoc->peer.retran_path = t;
+			break;
 		default:
 			printk(KERN_WARNING "Impossible command: %u, %p\n",
 			       cmd->verb, cmd->obj.ptr);

net/sctp/sm_statefuns.c

@@ -472,8 +472,6 @@ sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
 	 */
 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
-	sctp_add_cmd_sf(commands, SCTP_CMD_COUNTER_RESET,
-			SCTP_COUNTER(SCTP_COUNTER_INIT_ERROR));
 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
@@ -674,6 +672,15 @@ sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep,
 	if (!sctp_vtag_verify(chunk, asoc))
 		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
 
+	/* Reset init error count upon receipt of COOKIE-ACK,
+	 * to avoid problems with the managemement of this
+	 * counter in stale cookie situations when a transition back
+	 * from the COOKIE-ECHOED state to the COOKIE-WAIT
+	 * state is performed.
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_COUNTER_RESET,
+	                SCTP_COUNTER(SCTP_COUNTER_INIT_ERROR));
+
 	/* RFC 2960 5.1 Normal Establishment of an Association
 	 *
 	 * E) Upon reception of the COOKIE ACK, endpoint "A" will move
@@ -1872,8 +1879,6 @@ sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
 	time_t stale;
 	sctp_cookie_preserve_param_t bht;
 	sctp_errhdr_t *err;
-	struct list_head *pos;
-	struct sctp_transport *t;
 	struct sctp_chunk *reply;
 	struct sctp_bind_addr *bp;
 	int attempts;
@@ -1920,20 +1925,27 @@ sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep,
 	/* Clear peer's init_tag cached in assoc as we are sending a new INIT */
 	sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
 
+	/* Stop pending T3-rtx and heartbeat timers */
+	sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
+	sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
+
+	/* Delete non-primary peer ip addresses since we are transitioning
+	 * back to the COOKIE-WAIT state
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
+
+	/* If we've sent any data bundled with COOKIE-ECHO we will need to 
+	 * resend 
+	 */
+	sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, 
+			SCTP_TRANSPORT(asoc->peer.primary_path));
+
 	/* Cast away the const modifier, as we want to just
 	 * rerun it through as a sideffect.
 	 */
 	sctp_add_cmd_sf(commands, SCTP_CMD_COUNTER_INC,
 			SCTP_COUNTER(SCTP_COUNTER_INIT_ERROR));
 
-	/* If we've sent any data bundled with COOKIE-ECHO we need to
-	 * resend.
-	 */
-	list_for_each(pos, &asoc->peer.transport_addr_list) {
-		t = list_entry(pos, struct sctp_transport, transports);
-		sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(t));
-	}
-
 	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
 			SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
 	sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,