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Commit 8b750ce5 authored by Vlad Yasevich's avatar Vlad Yasevich Committed by David S. Miller
Browse files

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: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
Tested-by: default avatarWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 62aeaff5

net/sctp/outqueue.c

+48 −34
Original line number Diff line number Diff line
@@ -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;