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sctp: Flush the queue only once during fast retransmit.

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When fast retransmit is triggered by a sack, we should flush the queue
only once so that only 1 retransmit happens.  Also, since we could
potentially have non-fast-rtx chunks on the retransmit queue, we need
make sure any chunks eligable for fast retransmit are sent first
during fast retransmission.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Tested-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Yasevich 2008-06-04 12:39:36 -07:00 committed by David S. Miller
parent 62aeaff5cc
commit 8b750ce54b
1 changed files with 48 additions and 34 deletions
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62
net/sctp/outqueue.c
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@ -520,8 +520,14 @@ void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
* the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
* following the procedures outlined in C1 - C5.
*/
if (reason == SCTP_RTXR_T3_RTX)
sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
/* Flush the queues only on timeout, since fast_rtx is only
* triggered during sack processing and the queue
* will be flushed at the end.
*/
if (reason != SCTP_RTXR_FAST_RTX)
error = sctp_outq_flush(q, /* rtx_timeout */ 1);
if (error)
@ -540,7 +546,6 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
int rtx_timeout, int *start_timer)
{
struct list_head *lqueue;
struct list_head *lchunk;
struct sctp_transport *transport = pkt->transport;
sctp_xmit_t status;
struct sctp_chunk *chunk, *chunk1;
@ -548,12 +553,16 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
int fast_rtx;
int error = 0;
int timer = 0;
int done = 0;
asoc = q->asoc;
lqueue = &q->retransmit;
fast_rtx = q->fast_rtx;
/* RFC 2960 6.3.3 Handle T3-rtx Expiration
/* This loop handles time-out retransmissions, fast retransmissions,
* and retransmissions due to opening of whindow.
*
* RFC 2960 6.3.3 Handle T3-rtx Expiration
*
* E3) Determine how many of the earliest (i.e., lowest TSN)
* outstanding DATA chunks for the address for which the
@ -568,12 +577,12 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
* [Just to be painfully clear, if we are retransmitting
* because a timeout just happened, we should send only ONE
* packet of retransmitted data.]
*
* For fast retransmissions we also send only ONE packet. However,
* if we are just flushing the queue due to open window, we'll
* try to send as much as possible.
*/
lchunk = sctp_list_dequeue(lqueue);
while (lchunk) {
chunk = list_entry(lchunk, struct sctp_chunk,
transmitted_list);
list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
/* Make sure that Gap Acked TSNs are not retransmitted. A
* simple approach is just to move such TSNs out of the
@ -581,11 +590,18 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
* next chunk.
*/
if (chunk->tsn_gap_acked) {
list_add_tail(lchunk, &transport->transmitted);
lchunk = sctp_list_dequeue(lqueue);
list_del(&chunk->transmitted_list);
list_add_tail(&chunk->transmitted_list,
&transport->transmitted);
continue;
}
/* If we are doing fast retransmit, ignore non-fast_rtransmit
* chunks
*/
if (fast_rtx && !chunk->fast_retransmit)
continue;
/* Attempt to append this chunk to the packet. */
status = sctp_packet_append_chunk(pkt, chunk);
@ -597,12 +613,10 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
/* If we are retransmitting, we should only
* send a single packet.
*/
if (rtx_timeout || fast_rtx) {
list_add(lchunk, lqueue);
lchunk = NULL;
}
if (rtx_timeout || fast_rtx)
done = 1;
/* Bundle lchunk in the next round. */
/* Bundle next chunk in the next round. */
break;
case SCTP_XMIT_RWND_FULL:
@ -612,8 +626,7 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
/* Stop sending DATA as there is no more room
* at the receiver.
*/
list_add(lchunk, lqueue);
lchunk = NULL;
done = 1;
break;
case SCTP_XMIT_NAGLE_DELAY:
@ -621,15 +634,16 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
error = sctp_packet_transmit(pkt);
/* Stop sending DATA because of nagle delay. */
list_add(lchunk, lqueue);
lchunk = NULL;
done = 1;
break;
default:
/* The append was successful, so add this chunk to
* the transmitted list.
*/
list_add_tail(lchunk, &transport->transmitted);
list_del(&chunk->transmitted_list);
list_add_tail(&chunk->transmitted_list,
&transport->transmitted);
/* Mark the chunk as ineligible for fast retransmit
* after it is retransmitted.
@ -646,9 +660,6 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
timer = 2;
q->empty = 0;
/* Retrieve a new chunk to bundle. */
lchunk = sctp_list_dequeue(lqueue);
break;
}
@ -656,18 +667,21 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
if (!error && !timer)
timer = 1;
if (done)
break;
}
/* If we are here due to a retransmit timeout or a fast
* retransmit and if there are any chunks left in the retransmit
* queue that could not fit in the PMTU sized packet, they need
* to be marked as ineligible for a subsequent fast retransmit.
*/
if (rtx_timeout && fast_rtx) {
if (rtx_timeout || fast_rtx) {
list_for_each_entry(chunk1, lqueue, transmitted_list) {
if (chunk1->fast_retransmit > 0)
chunk1->fast_retransmit = -1;
}
}
}
*start_timer = timer;