[SCTP]: Fix 'fast retransmit' to send a TSN only once.

SCTP used to "fast retransmit" a TSN every time we hit the number
of missing reports for the TSN.  However the Implementers Guide
specifies that we should only "fast retransmit" a given TSN once.
Subsequent retransmits should be timeouts only. Also change the
number of missing reports to 3 as per the latest IG(similar to TCP).

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Yasevich 2006-02-02 16:57:31 -08:00 committed by David S. Miller
parent 4641e7a334
commit 27852c26ba
3 changed files with 9 additions and 7 deletions

View file

@ -700,7 +700,7 @@ struct sctp_chunk {
__u8 ecn_ce_done; /* Have we processed the ECN CE bit? */
__u8 pdiscard; /* Discard the whole packet now? */
__u8 tsn_gap_acked; /* Is this chunk acked by a GAP ACK? */
__u8 fast_retransmit; /* Is this chunk fast retransmitted? */
__s8 fast_retransmit; /* Is this chunk fast retransmitted? */
__u8 tsn_missing_report; /* Data chunk missing counter. */
};

View file

@ -608,7 +608,7 @@ static sctp_xmit_t sctp_packet_append_data(struct sctp_packet *packet,
* When a Fast Retransmit is being performed the sender SHOULD
* ignore the value of cwnd and SHOULD NOT delay retransmission.
*/
if (!chunk->fast_retransmit)
if (chunk->fast_retransmit <= 0)
if (transport->flight_size >= transport->cwnd) {
retval = SCTP_XMIT_RWND_FULL;
goto finish;

View file

@ -406,7 +406,7 @@ void sctp_retransmit_mark(struct sctp_outq *q,
* chunks that are not yet acked should be added to the
* retransmit queue.
*/
if ((fast_retransmit && chunk->fast_retransmit) ||
if ((fast_retransmit && (chunk->fast_retransmit > 0)) ||
(!fast_retransmit && !chunk->tsn_gap_acked)) {
/* RFC 2960 6.2.1 Processing a Received SACK
*
@ -603,7 +603,8 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
/* Mark the chunk as ineligible for fast retransmit
* after it is retransmitted.
*/
chunk->fast_retransmit = 0;
if (chunk->fast_retransmit > 0)
chunk->fast_retransmit = -1;
*start_timer = 1;
q->empty = 0;
@ -621,7 +622,8 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
list_for_each(lchunk1, lqueue) {
chunk1 = list_entry(lchunk1, struct sctp_chunk,
transmitted_list);
chunk1->fast_retransmit = 0;
if (chunk1->fast_retransmit > 0)
chunk1->fast_retransmit = -1;
}
}
}
@ -1562,11 +1564,11 @@ static void sctp_mark_missing(struct sctp_outq *q,
/*
* M4) If any DATA chunk is found to have a
* 'TSN.Missing.Report'
* value larger than or equal to 4, mark that chunk for
* value larger than or equal to 3, mark that chunk for
* retransmission and start the fast retransmit procedure.
*/
if (chunk->tsn_missing_report >= 4) {
if (chunk->tsn_missing_report >= 3) {
chunk->fast_retransmit = 1;
do_fast_retransmit = 1;
}