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Date: Wed, 4 Jun 2008 14:25:50 -0400
From: Vlad Yasevich <vladislav.yasevich@...com>
To: netdev@...r.kernel.org
Cc: linux-sctp@...r.kernel.org, davem@...emloft.net,
Vlad Yasevich <vladislav.yasevich@...com>
Subject: [PATCH 5/6] SCTP: Flush the queue only once during fast retransmit.
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@...com>
Tested-by: Wei Yongjun <yjwei@...fujitsu.com>
---
net/sctp/outqueue.c | 82 ++++++++++++++++++++++++++++++---------------------
1 files changed, 48 insertions(+), 34 deletions(-)
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 5d3c441..ace6770 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -520,9 +520,15 @@ 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.
*/
- sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
+ if (reason == SCTP_RTXR_T3_RTX)
+ sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
- error = sctp_outq_flush(q, /* rtx_timeout */ 1);
+ /* 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)
q->asoc->base.sk->sk_err = -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;
}
@@ -656,16 +667,19 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
if (!error && !timer)
timer = 1;
- /* 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) {
- list_for_each_entry(chunk1, lqueue, transmitted_list) {
- if (chunk1->fast_retransmit > 0)
- chunk1->fast_retransmit = -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) {
+ list_for_each_entry(chunk1, lqueue, transmitted_list) {
+ if (chunk1->fast_retransmit > 0)
+ chunk1->fast_retransmit = -1;
}
}
--
1.5.3.5
--
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