Re: [PATCH] For for each TSN t being newly acked (Not only cumulatively, but also SELECTIVELY) cacc_saw_newack should be set to 1.

Vlad Yasevich
2013-10-15T17:25:13Z

On 10/15/2013 12:59 PM, Chang Xiangzhong wrote:
> Signed-off-by: Xiangzhong Chang <changxiangzhong@gmail.com>
> ---
> net/sctp/outqueue.c | 142 ++++++++++++++++++++++++---------------------------
> 1 file changed, 68 insertions(+), 74 deletions(-)
>
> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
> index 94df758..f10d848 100644
> --- a/net/sctp/outqueue.c
> +++ b/net/sctp/outqueue.c
> @@ -1357,84 +1357,78 @@ static void sctp_check_transmitted(struct sctp_outq *q,
>
> tsn = ntohl(tchunk->subh.data_hdr->tsn);
> if (sctp_acked(sack, tsn)) {
> - /* If this queue is the retransmit queue, the
> - * retransmit timer has already reclaimed
> - * the outstanding bytes for this chunk, so only
> - * count bytes associated with a transport.
> - */
> - if (transport) {
> - /* If this chunk is being used for RTT
> - * measurement, calculate the RTT and update
> - * the RTO using this value.
> - *
> - * 6.3.1 C5) Karn's algorithm: RTT measurements
> - * MUST NOT be made using packets that were
> - * retransmitted (and thus for which it is
> - * ambiguous whether the reply was for the
> - * first instance of the packet or a later
> - * instance).
> - */
> - if (!tchunk->tsn_gap_acked &&
> - tchunk->rtt_in_progress) {
> - tchunk->rtt_in_progress = 0;
> - rtt = jiffies - tchunk->sent_at;
> - sctp_transport_update_rto(transport,
> - rtt);
> - }
> - }
> -
> - /* If the chunk hasn't been marked as ACKED,
> - * mark it and account bytes_acked if the
> - * chunk had a valid transport (it will not
> - * have a transport if ASCONF had deleted it
> - * while DATA was outstanding).
> - */
> if (!tchunk->tsn_gap_acked) {
> - tchunk->tsn_gap_acked = 1;
> - *highest_new_tsn_in_sack = tsn;
> - bytes_acked += sctp_data_size(tchunk);
> - if (!tchunk->transport)
> - migrate_bytes += sctp_data_size(tchunk);
> - forward_progress = true;
> + /* If this queue is the retransmit queue, the
> + * retransmit timer has already reclaimed
> + * the outstanding bytes for this chunk, so only
> + * count bytes associated with a transport.
> + *
> + * If this chunk is being used for RTT
> + * measurement, calculate the RTT and update
> + * the RTO using this value.
> + *
> + * 6.3.1 C5) Karn's algorithm: RTT measurements
> + * MUST NOT be made using packets that were
> + * retransmitted (and thus for which it is
> + * ambiguous whether the reply was for the
> + * first instance of the packet or a later
> + * instance).
> + */
> + if (transport && tchunk->rtt_in_progress) {
> + tchunk->rtt_in_progress = 0;
> + rtt = jiffies - tchunk->sent_at;
> + sctp_transport_update_rto(transport,
> + rtt);
> + }
> +
> + /* If the chunk hasn't been marked as ACKED,
> + * mark it and account bytes_acked if the
> + * chunk had a valid transport (it will not
> + * have a transport if ASCONF had deleted it
> + * while DATA was outstanding).
> + */
> + tchunk->tsn_gap_acked = 1;
> + *highest_new_tsn_in_sack = tsn;
> + bytes_acked += sctp_data_size(tchunk);
> + if (!tchunk->transport)
> + migrate_bytes += sctp_data_size(tchunk);
> + forward_progress = true;
> +
> + /*
> + * SFR-CACC algorithm:
> + * 2) If the SACK contains gap acks
> + * and the flag CHANGEOVER_ACTIVE is
> + * set the receiver of the SACK MUST
> + * take the following action:
> + *
> + * B) For each TSN t being acked that
> + * has not been acked in any SACK so
> + * far, set cacc_saw_newack to 1 for
> + * the destination that the TSN was
> + * sent to.
> + */
> + if (transport &&
> + sack->num_gap_ack_blocks &&
> + q->asoc->peer.primary_path->cacc.
> + changeover_active)
> + transport->cacc.cacc_saw_newack = 1;
> }

Indents should be tab based.
This is a bit more of a re-write that is needed for the this particualar
patch. What's wrong with just doing this?

@@ -1396,6 +1396,25 @@ static void sctp_check_transmitted(struct
sctp_outq *q,
if (!tchunk->transport)
migrate_bytes +=
sctp_data_size(tchunk);
forward_progress = true;
+
+ /*
+ * SFR-CACC algorithm:
+ * 2) If the SACK contains gap acks
+ * and the flag CHANGEOVER_ACTIVE is
+ * set the receiver of the SACK MUST
+ * take the following action:
+ *
+ * B) For each TSN t being acked that
+ * has not been acked in any SACK so
+ * far, set cacc_saw_newack to 1 for
+ * the destination that the TSN was
+ * sent to.
+ */
+ if (transport &&
+ sack->num_gap_ack_blocks &&
+ q->asoc->peer.primary_path->cacc.
+ changeover_active)
+ transport->cacc.cacc_saw_newack = 1;
}

if (TSN_lte(tsn, sack_ctsn)) {

-vlad

>
> if (TSN_lte(tsn, sack_ctsn)) {
> - /* RFC 2960 6.3.2 Retransmission Timer Rules
> - *
> - * R3) Whenever a SACK is received
> - * that acknowledges the DATA chunk
> - * with the earliest outstanding TSN
> - * for that address, restart T3-rtx
> - * timer for that address with its
> - * current RTO.
> - */
> - restart_timer = 1;
> - forward_progress = true;
> -
> - if (!tchunk->tsn_gap_acked) {
> - /*
> - * SFR-CACC algorithm:
> - * 2) If the SACK contains gap acks
> - * and the flag CHANGEOVER_ACTIVE is
> - * set the receiver of the SACK MUST
> - * take the following action:
> - *
> - * B) For each TSN t being acked that
> - * has not been acked in any SACK so
> - * far, set cacc_saw_newack to 1 for
> - * the destination that the TSN was
> - * sent to.
> - */
> - if (transport &&
> - sack->num_gap_ack_blocks &&
> - q->asoc->peer.primary_path->cacc.
> - changeover_active)
> - transport->cacc.cacc_saw_newack
> - = 1;
> - }
> -
> - list_add_tail(&tchunk->transmitted_list,
> - &q->sacked);
> + /* RFC 2960 6.3.2 Retransmission Timer Rules
> + *
> + * R3) Whenever a SACK is received
> + * that acknowledges the DATA chunk
> + * with the earliest outstanding TSN
> + * for that address, restart T3-rtx
> + * timer for that address with its
> + * current RTO.
> + */
> + restart_timer = 1;
> + forward_progress = true;
> +
> + list_add_tail(&tchunk->transmitted_list,
> + &q->sacked);
> } else {
> /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
> * M2) Each time a SACK arrives reporting
>