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Date: Wed, 4 Jun 2008 14:25:49 -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 4/6] SCTP: Start T3-RTX timer when fast retransmitting lowest TSN
When we are trying to fast retransmit the lowest outstanding TSN, we
need to restart the T3-RTX timer, so that subsequent timeouts will
correctly tag all the packets necessary for retransmissions.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@...com>
Tested-by: Wei Yongjun <yjwei@...fujitsu.com>
---
include/net/sctp/structs.h | 5 ++++-
net/sctp/outqueue.c | 42 +++++++++++++++++++++++++++++++-----------
net/sctp/transport.c | 4 ++--
3 files changed, 37 insertions(+), 14 deletions(-)
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 4f7b587..1014c77 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1050,7 +1050,7 @@ void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
struct sctp_sock *);
void sctp_transport_pmtu(struct sctp_transport *);
void sctp_transport_free(struct sctp_transport *);
-void sctp_transport_reset_timers(struct sctp_transport *);
+void sctp_transport_reset_timers(struct sctp_transport *, int);
void sctp_transport_hold(struct sctp_transport *);
void sctp_transport_put(struct sctp_transport *);
void sctp_transport_update_rto(struct sctp_transport *, __u32);
@@ -1140,6 +1140,9 @@ struct sctp_outq {
/* How many unackd bytes do we have in-flight? */
__u32 outstanding_bytes;
+ /* Are we doing fast-rtx on this queue */
+ char fast_rtx;
+
/* Corked? */
char cork;
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 59edfd2..5d3c441 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -208,6 +208,7 @@ void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
INIT_LIST_HEAD(&q->sacked);
INIT_LIST_HEAD(&q->abandoned);
+ q->fast_rtx = 0;
q->outstanding_bytes = 0;
q->empty = 1;
q->cork = 0;
@@ -500,6 +501,7 @@ void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
case SCTP_RTXR_FAST_RTX:
SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS);
sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
+ q->fast_rtx = 1;
break;
case SCTP_RTXR_PMTUD:
SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS);
@@ -543,10 +545,13 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
sctp_xmit_t status;
struct sctp_chunk *chunk, *chunk1;
struct sctp_association *asoc;
+ int fast_rtx;
int error = 0;
+ int timer = 0;
asoc = q->asoc;
lqueue = &q->retransmit;
+ fast_rtx = q->fast_rtx;
/* RFC 2960 6.3.3 Handle T3-rtx Expiration
*
@@ -587,13 +592,12 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
switch (status) {
case SCTP_XMIT_PMTU_FULL:
/* Send this packet. */
- if ((error = sctp_packet_transmit(pkt)) == 0)
- *start_timer = 1;
+ error = sctp_packet_transmit(pkt);
/* If we are retransmitting, we should only
* send a single packet.
*/
- if (rtx_timeout) {
+ if (rtx_timeout || fast_rtx) {
list_add(lchunk, lqueue);
lchunk = NULL;
}
@@ -603,8 +607,7 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
case SCTP_XMIT_RWND_FULL:
/* Send this packet. */
- if ((error = sctp_packet_transmit(pkt)) == 0)
- *start_timer = 1;
+ error = sctp_packet_transmit(pkt);
/* Stop sending DATA as there is no more room
* at the receiver.
@@ -615,8 +618,7 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
case SCTP_XMIT_NAGLE_DELAY:
/* Send this packet. */
- if ((error = sctp_packet_transmit(pkt)) == 0)
- *start_timer = 1;
+ error = sctp_packet_transmit(pkt);
/* Stop sending DATA because of nagle delay. */
list_add(lchunk, lqueue);
@@ -635,7 +637,14 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
if (chunk->fast_retransmit > 0)
chunk->fast_retransmit = -1;
- *start_timer = 1;
+ /* Force start T3-rtx timer when fast retransmitting
+ * the earliest outstanding TSN
+ */
+ if (!timer && fast_rtx &&
+ ntohl(chunk->subh.data_hdr->tsn) ==
+ asoc->ctsn_ack_point + 1)
+ timer = 2;
+
q->empty = 0;
/* Retrieve a new chunk to bundle. */
@@ -643,12 +652,16 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
break;
}
+ /* Set the timer if there were no errors */
+ 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 && !lchunk) {
+ if (rtx_timeout && fast_rtx) {
list_for_each_entry(chunk1, lqueue, transmitted_list) {
if (chunk1->fast_retransmit > 0)
chunk1->fast_retransmit = -1;
@@ -656,6 +669,12 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
}
}
+ *start_timer = timer;
+
+ /* Clear fast retransmit hint */
+ if (fast_rtx)
+ q->fast_rtx = 0;
+
return error;
}
@@ -862,7 +881,8 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
rtx_timeout, &start_timer);
if (start_timer)
- sctp_transport_reset_timers(transport);
+ sctp_transport_reset_timers(transport,
+ start_timer-1);
/* This can happen on COOKIE-ECHO resend. Only
* one chunk can get bundled with a COOKIE-ECHO.
@@ -977,7 +997,7 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
list_add_tail(&chunk->transmitted_list,
&transport->transmitted);
- sctp_transport_reset_timers(transport);
+ sctp_transport_reset_timers(transport, start_timer-1);
q->empty = 0;
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 3759027..33d9201 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -191,7 +191,7 @@ static void sctp_transport_destroy(struct sctp_transport *transport)
/* Start T3_rtx timer if it is not already running and update the heartbeat
* timer. This routine is called every time a DATA chunk is sent.
*/
-void sctp_transport_reset_timers(struct sctp_transport *transport)
+void sctp_transport_reset_timers(struct sctp_transport *transport, int force)
{
/* RFC 2960 6.3.2 Retransmission Timer Rules
*
@@ -201,7 +201,7 @@ void sctp_transport_reset_timers(struct sctp_transport *transport)
* address.
*/
- if (!timer_pending(&transport->T3_rtx_timer))
+ if (force || !timer_pending(&transport->T3_rtx_timer))
if (!mod_timer(&transport->T3_rtx_timer,
jiffies + transport->rto))
sctp_transport_hold(transport);
--
1.5.3.5
--
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