svn commit: r214928 - head/sys/netinet

[Michael Tuexen]

Author: tuexen
Date: Sun Nov  7 17:44:04 2010
New Revision: 214928
URL: http://svn.freebsd.org/changeset/base/214928

Log:
  * Use exponential backoff for retransmission of SHUTDOWN and
    SHUTDOWN-ACK chunks.
  * While there, do some cleanups.
  
  MFC after: 3 days.

Modified:
  head/sys/netinet/sctp_timer.c

Modified: head/sys/netinet/sctp_timer.c
==============================================================================
--- head/sys/netinet/sctp_timer.c	Sun Nov  7 17:41:09 2010	(r214927)
+++ head/sys/netinet/sctp_timer.c	Sun Nov  7 17:44:04 2010	(r214928)
@@ -291,6 +291,10 @@ sctp_threshold_management(struct sctp_in
 	return (0);
 }
 
+/*
+ * sctp_find_alternate_net() returns a non-NULL pointer as long
+ * the argument net is non-NULL.
+ */
 struct sctp_nets *
 sctp_find_alternate_net(struct sctp_tcb *stcb,
     struct sctp_nets *net,
@@ -440,8 +444,7 @@ sctp_find_alternate_net(struct sctp_tcb 
 	else if (mode == 1) {
 		TAILQ_FOREACH(mnet, &stcb->asoc.nets, sctp_next) {
 			if (((mnet->dest_state & SCTP_ADDR_REACHABLE) != SCTP_ADDR_REACHABLE) ||
-			    (mnet->dest_state & SCTP_ADDR_UNCONFIRMED)
-			    ) {
+			    (mnet->dest_state & SCTP_ADDR_UNCONFIRMED)) {
 				/*
 				 * will skip ones that are not-reachable or
 				 * unconfirmed
@@ -505,12 +508,10 @@ sctp_find_alternate_net(struct sctp_tcb 
 			}
 			alt->src_addr_selected = 0;
 		}
-		if (
-		    ((alt->dest_state & SCTP_ADDR_REACHABLE) == SCTP_ADDR_REACHABLE) &&
-		    (alt->ro.ro_rt != NULL) &&
 		/* sa_ignore NO_NULL_CHK */
-		    (!(alt->dest_state & SCTP_ADDR_UNCONFIRMED))
-		    ) {
+		if (((alt->dest_state & SCTP_ADDR_REACHABLE) == SCTP_ADDR_REACHABLE) &&
+		    (alt->ro.ro_rt != NULL) &&
+		    (!(alt->dest_state & SCTP_ADDR_UNCONFIRMED))) {
 			/* Found a reachable address */
 			break;
 		}
@@ -549,8 +550,6 @@ sctp_find_alternate_net(struct sctp_tcb 
 	return (alt);
 }
 
-
-
 static void
 sctp_backoff_on_timeout(struct sctp_tcb *stcb,
     struct sctp_nets *net,
@@ -1021,8 +1020,7 @@ sctp_t3rxt_timer(struct sctp_inpcb *inp,
 		 * used, then pick dest with largest ssthresh for any
 		 * retransmission.
 		 */
-		alt = net;
-		alt = sctp_find_alternate_net(stcb, alt, 1);
+		alt = sctp_find_alternate_net(stcb, net, 1);
 		/*
 		 * CUCv2: If a different dest is picked for the
 		 * retransmission, then new (rtx-)pseudo_cumack needs to be
@@ -1213,7 +1211,7 @@ sctp_t1init_timer(struct sctp_inpcb *inp
 		struct sctp_nets *alt;
 
 		alt = sctp_find_alternate_net(stcb, stcb->asoc.primary_destination, 0);
-		if ((alt != NULL) && (alt != stcb->asoc.primary_destination)) {
+		if (alt != stcb->asoc.primary_destination) {
 			sctp_move_chunks_from_net(stcb, stcb->asoc.primary_destination);
 			stcb->asoc.primary_destination = alt;
 		}
@@ -1480,6 +1478,7 @@ sctp_delete_prim_timer(struct sctp_inpcb
  * For the shutdown and shutdown-ack, we do not keep one around on the
  * control queue. This means we must generate a new one and call the general
  * chunk output routine, AFTER having done threshold management.
+ * It is assumed that net is non-NULL.
  */
 int
 sctp_shutdown_timer(struct sctp_inpcb *inp, struct sctp_tcb *stcb,
@@ -1492,18 +1491,13 @@ sctp_shutdown_timer(struct sctp_inpcb *i
 		/* Assoc is over */
 		return (1);
 	}
+	sctp_backoff_on_timeout(stcb, net, 1, 0, 0);
 	/* second select an alternative */
 	alt = sctp_find_alternate_net(stcb, net, 0);
 
 	/* third generate a shutdown into the queue for out net */
-	if (alt) {
-		sctp_send_shutdown(stcb, alt);
-	} else {
-		/*
-		 * if alt is NULL, there is no dest to send to??
-		 */
-		return (0);
-	}
+	sctp_send_shutdown(stcb, alt);
+
 	/* fourth restart timer */
 	sctp_timer_start(SCTP_TIMER_TYPE_SHUTDOWN, inp, stcb, alt);
 	return (0);
@@ -1520,6 +1514,7 @@ sctp_shutdownack_timer(struct sctp_inpcb
 		/* Assoc is over */
 		return (1);
 	}
+	sctp_backoff_on_timeout(stcb, net, 1, 0, 0);
 	/* second select an alternative */
 	alt = sctp_find_alternate_net(stcb, net, 0);