SCTP: Do not retransmit chunks that are newer then rtt.

When performing a retransmit, do not include the chunk if
it was sent less then 1 rtt ago.  The reason is that we
may receive the SACK very soon and wouldn't retransmit.
Suggested by Randy Stewart.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 992f361084b7..28f4fe77ceee 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -421,6 +421,13 @@ void sctp_retransmit_mark(struct sctp_outq *q,
                  */
                 if ((fast_retransmit && (chunk->fast_retransmit > 0)) ||
                    (!fast_retransmit && !chunk->tsn_gap_acked)) {
+                        /* If this chunk was sent less then 1 rto ago, do not
+                         * retransmit this chunk, but give the peer time
+                         * to acknowlege it.
+                         */
+                        if ((jiffies - chunk->sent_at) < transport->rto)
+                                continue;
+
                         /* RFC 2960 6.2.1 Processing a Received SACK
                          *
                          * C) Any time a DATA chunk is marked for