sctp: Fix the RTO-doubling on idle-link heartbeats

[safe/jmp/linux-2.6] / net / sctp / sm_sideeffect.c

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index e1d6076..0146cfb 100644 (file)
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -461,9 +461,15 @@ static void sctp_do_8_2_transport_strike(struct sctp_association *asoc,
         * expires, set RTO <- RTO * 2 ("back off the timer").  The
         * maximum value discussed in rule C7 above (RTO.max) may be
         * used to provide an upper bound to this doubling operation.
+        *
+        * Special Case:  the first HB doesn't trigger exponential backoff.
+        * The first unacknowleged HB triggers it.  We do this with a flag
+        * that indicates that we have an outstanding HB.
         */
-       transport->last_rto = transport->rto;
-       transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
+       if (transport->hb_sent) {
+               transport->last_rto = transport->rto;
+               transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
+       }
 }
 
 /* Worker routine to handle INIT command failure.  */
@@ -621,6 +627,11 @@ static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
        t->error_count = 0;
        t->asoc->overall_error_count = 0;
 
+       /* Clear the hb_sent flag to signal that we had a good
+        * acknowledgement.
+        */
+       t->hb_sent = 0;
+
        /* Mark the destination transport address as active if it is not so
         * marked.
         */
@@ -657,6 +668,8 @@ static void sctp_cmd_transport_reset(sctp_cmd_seq_t *cmds,
 
        /* Mark one strike against a transport.  */
        sctp_do_8_2_transport_strike(asoc, t);
+
+       t->hb_sent = 1;
 }
 
 /* Helper function to process the process SACK command.  */