SCTP: Fix difference cases of retransmit.

Commit d0ce92910bc04e107b2f3f2048f07e94f570035d broke several retransmit
cases including fast retransmit.  The reason is that we should
only delay by rto while doing retranmists as a result of a timeout.
Retransmit as a result of path mtu discover, fast retransmit, or
other evernts that should trigger immidiate retransmissions got broken.

Also, since rto is doubled prior to marking of packets elegable for
retransmission, we never marked correct chunks anyway.

The fix is provide a reason for a given retransmission so that we
can mark chunks appropriately and to save the old rto value to do
comparisons against.

All regressions tests passed with this code.

Spotted by Wei Yongjun <yjwei@cn.fujitsu.com>

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

1 files changed, 17 insertions, 16 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index e315c6c756ca..99a3db5d5fae 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -382,7 +382,7 @@ static void sctp_insert_list(struct list_head *head, struct list_head *new)
 /* Mark all the eligible packets on a transport for retransmission.  */
 void sctp_retransmit_mark(struct sctp_outq *q,
                           struct sctp_transport *transport,
-                          __u8 fast_retransmit)
+                          __u8 reason)
 {
         struct list_head *lchunk, *ltemp;
         struct sctp_chunk *chunk;
@@ -412,20 +412,20 @@ void sctp_retransmit_mark(struct sctp_outq *q,
                         continue;
                 }
 
-                /* If we are doing retransmission due to a fast retransmit,
-                 * only the chunk's that are marked for fast retransmit
-                 * should be added to the retransmit queue.  If we are doing
-                 * retransmission due to a timeout or pmtu discovery, only the
-                 * chunks that are not yet acked should be added to the
-                 * retransmit queue.
+                /* If we are doing  retransmission due to a timeout or pmtu
+                 * discovery, only the  chunks that are not yet acked should
+                 * be added to the retransmit queue.
                  */
-                if ((fast_retransmit && (chunk->fast_retransmit > 0)) ||
-                   (!fast_retransmit && !chunk->tsn_gap_acked)) {
+                if ((reason == SCTP_RTXR_FAST_RTX  &&
+                            (chunk->fast_retransmit > 0)) ||
+                    (reason != SCTP_RTXR_FAST_RTX  && !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.
+                         * to acknowlege it.  Do this only when
+                         * retransmitting due to T3 timeout.
                          */
-                        if ((jiffies - chunk->sent_at) < transport->rto)
+                        if (reason == SCTP_RTXR_T3_RTX &&
+                            (jiffies - chunk->sent_at) < transport->last_rto)
                                 continue;
 
                         /* RFC 2960 6.2.1 Processing a Received SACK
@@ -467,10 +467,10 @@ void sctp_retransmit_mark(struct sctp_outq *q,
                 }
         }
 
-        SCTP_DEBUG_PRINTK("%s: transport: %p, fast_retransmit: %d, "
+        SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
                           "cwnd: %d, ssthresh: %d, flight_size: %d, "
                           "pba: %d\n", __FUNCTION__,
-                          transport, fast_retransmit,
+                          transport, reason,
                           transport->cwnd, transport->ssthresh,
                           transport->flight_size,
                           transport->partial_bytes_acked);
@@ -484,7 +484,6 @@ void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
                      sctp_retransmit_reason_t reason)
 {
         int error = 0;
-        __u8 fast_retransmit = 0;
 
         switch(reason) {
         case SCTP_RTXR_T3_RTX:
@@ -499,16 +498,18 @@ void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
         case SCTP_RTXR_FAST_RTX:
                 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS);
                 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
-                fast_retransmit = 1;
                 break;
         case SCTP_RTXR_PMTUD:
                 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS);
                 break;
+        case SCTP_RTXR_T1_RTX:
+                SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS);
+                break;
         default:
                 BUG();
         }
 
-        sctp_retransmit_mark(q, transport, fast_retransmit);
+        sctp_retransmit_mark(q, transport, reason);
 
         /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
          * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by