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

SCTP incorrectly doubles rto ever time a Hearbeat chunk
is generated.   However RFC 4960 states:

   On an idle destination address that is allowed to heartbeat, it is
   recommended that a HEARTBEAT chunk is sent once per RTO of that
   destination address plus the protocol parameter 'HB.interval', with
   jittering of +/- 50% of the RTO value, and exponential backoff of the
   RTO if the previous HEARTBEAT is unanswered.

Essentially, of if the heartbean is unacknowledged, do we double the RTO.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index e745c118f239..5c29b14ee9af 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -79,6 +79,7 @@ static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
         peer->rttvar = 0;
         peer->srtt = 0;
         peer->rto_pending = 0;
+        peer->hb_sent = 0;
         peer->fast_recovery = 0;
 
         peer->last_time_heard = jiffies;
@@ -608,6 +609,7 @@ void sctp_transport_reset(struct sctp_transport *t)
         t->flight_size = 0;
         t->error_count = 0;
         t->rto_pending = 0;
+        t->hb_sent = 0;
         t->fast_recovery = 0;
 
         /* Initialize the state information for SFR-CACC */