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>
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index e315c6c..99a3db5 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -382,7 +382,7 @@
/* 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 @@
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 @@
}
}
- 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 @@
sctp_retransmit_reason_t reason)
{
int error = 0;
- __u8 fast_retransmit = 0;
switch(reason) {
case SCTP_RTXR_T3_RTX:
@@ -499,16 +498,18 @@
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
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index bbdc938..78d1a8a 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -453,6 +453,7 @@
* maximum value discussed in rule C7 above (RTO.max) may be
* used to provide an upper bound to this doubling operation.
*/
+ transport->last_rto = transport->rto;
transport->rto = min((transport->rto * 2), transport->asoc->rto_max);
}
@@ -1267,6 +1268,12 @@
sctp_ootb_pkt_free(packet);
break;
+ case SCTP_CMD_T1_RETRAN:
+ /* Mark a transport for retransmission. */
+ sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
+ SCTP_RTXR_T1_RTX);
+ break;
+
case SCTP_CMD_RETRAN:
/* Mark a transport for retransmission. */
sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
@@ -1393,7 +1400,8 @@
list_for_each(pos, &asoc->peer.transport_addr_list) {
t = list_entry(pos, struct sctp_transport,
transports);
- sctp_retransmit_mark(&asoc->outqueue, t, 0);
+ sctp_retransmit_mark(&asoc->outqueue, t,
+ SCTP_RTXR_T1_RTX);
}
sctp_add_cmd_sf(commands,
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index f01b408..a66075a 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -2305,7 +2305,7 @@
/* If we've sent any data bundled with COOKIE-ECHO we will need to
* resend
*/
- sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN,
+ sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
SCTP_TRANSPORT(asoc->peer.primary_path));
/* Cast away the const modifier, as we want to just
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 5f467c9..d55ce83 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -74,8 +74,8 @@
* given destination transport address, set RTO to the protocol
* parameter 'RTO.Initial'.
*/
+ peer->last_rto = peer->rto = msecs_to_jiffies(sctp_rto_initial);
peer->rtt = 0;
- peer->rto = msecs_to_jiffies(sctp_rto_initial);
peer->rttvar = 0;
peer->srtt = 0;
peer->rto_pending = 0;
@@ -385,6 +385,7 @@
tp->rto = tp->asoc->rto_max;
tp->rtt = rtt;
+ tp->last_rto = tp->rto;
/* Reset rto_pending so that a new RTT measurement is started when a
* new data chunk is sent.
@@ -578,7 +579,7 @@
*/
t->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
t->ssthresh = asoc->peer.i.a_rwnd;
- t->rto = asoc->rto_initial;
+ t->last_rto = t->rto = asoc->rto_initial;
t->rtt = 0;
t->srtt = 0;
t->rttvar = 0;