path: root/net/sctp/transport.c
diff options
authorAndrei Pelinescu-Onciul <andrei@iptel.org>2009-11-29 00:14:02 -0800
committerDavid S. Miller <davem@davemloft.net>2009-11-29 00:14:02 -0800
commit5fdd4baef6195a1f2960e901c8877e2105f832ca (patch)
tree198a3f2df2bea3c5239c95957e21f3680908ddf6 /net/sctp/transport.c
parentpktgen: Fix netdevice unregister (diff)
sctp: on T3_RTX retransmit all the in-flight chunks
When retransmitting due to T3 timeout, retransmit all the in-flight chunks for the corresponding transport/path, including chunks sent less then 1 rto ago. This is the correct behaviour according to rfc4960 section 6.3.3 E3 and "Note: Any DATA chunks that were sent to the address for which the T3-rtx timer expired but did not fit in one MTU (rule E3 above) should be marked for retransmission and sent as soon as cwnd allows (normally, when a SACK arrives). ". This fixes problems when more then one path is present and the T3 retransmission of the first chunk that timeouts stops the T3 timer for the initial active path, leaving all the other in-flight chunks waiting forever or until a new chunk is transmitted on the same path and timeouts (and this will happen only if the cwnd allows sending new chunks, but since cwnd was dropped to MTU by the timeout => it will wait until the first heartbeat). Example: 10 packets in flight, sent at 0.1 s intervals on the primary path. The primary path is down and the first packet timeouts. The first packet is retransmitted on another path, the T3 timer for the primary path is stopped and cwnd is set to MTU. All the other 9 in-flight packets will not be retransmitted (unless more new packets are sent on the primary path which depend on cwnd allowing it, and even in this case the 9 packets will be retransmitted only after a new packet timeouts which even in the best case would be more then RTO). This commit reverts d0ce92910bc04e107b2f3f2048f07e94f570035d and also removes the now unused transport->last_rto, introduced in b6157d8e03e1e780660a328f7183bcbfa4a93a19. p.s The problem is not only when multiple paths are there. It can happen in a single homed environment. If the application stops sending data, it possible to have a hung association. Signed-off-by: Andrei Pelinescu-Onciul <andrei@iptel.org> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
1 files changed, 2 insertions, 3 deletions
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 3b141bb32faf..37a1184d789f 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -74,7 +74,7 @@ static struct sctp_transport *sctp_transport_init(struct sctp_transport *peer,
* given destination transport address, set RTO to the protocol
* parameter 'RTO.Initial'.
- peer->last_rto = peer->rto = msecs_to_jiffies(sctp_rto_initial);
+ peer->rto = msecs_to_jiffies(sctp_rto_initial);
peer->rtt = 0;
peer->rttvar = 0;
peer->srtt = 0;
@@ -386,7 +386,6 @@ void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt)
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.
@@ -602,7 +601,7 @@ void sctp_transport_reset(struct sctp_transport *t)
t->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380));
t->ssthresh = asoc->peer.i.a_rwnd;
- t->last_rto = t->rto = asoc->rto_initial;
+ t->rto = asoc->rto_initial;
t->rtt = 0;
t->srtt = 0;
t->rttvar = 0;