* [PATCH 09/29] Ignore irrelevant states on receiving feedback
@ 2007-04-12 21:15 Arnaldo Carvalho de Melo
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From: Arnaldo Carvalho de Melo @ 2007-04-12 21:15 UTC (permalink / raw)
To: dccp
This removes two currently irrelevant states in TX feedback handling:
* the NO_SENT state is not triggered, since currently DCCP only operates in
half-connections (in which this state is irrelevant). When upgrading to
bidirectional half-connections, other changes are required anyhow, so that
there is no loss in removing this currently unsupported state.
* the TERM (terminating) state is uninteresting.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---
net/dccp/ccids/ccid3.c | 207 ++++++++++++++++++++++++------------------------
1 files changed, 102 insertions(+), 105 deletions(-)
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 9d661e4..22ba3f9 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -442,130 +442,127 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_DATAACK))
return;
+ /* only the established state is of interest here */
+ switch (hctx->ccid3hctx_state) {
+ case TFRC_SSTATE_NO_FBACK: /* fall through */
+ case TFRC_SSTATE_FBACK: break;
+ default: return;
+ }
+
+ /* get packet from history to look up t_recvdata */
+ packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
+ DCCP_SKB_CB(skb)->dccpd_ack_seq);
+ if (unlikely(packet = NULL)) {
+ DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist in history!\n",
+ dccp_role(sk), sk,
+ (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
+ dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
+ return;
+ }
+
opt_recv = &hctx->ccid3hctx_options_received;
- switch (hctx->ccid3hctx_state) {
- case TFRC_SSTATE_NO_FBACK:
- case TFRC_SSTATE_FBACK:
- /* get packet from history to look up t_recvdata */
- packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
- DCCP_SKB_CB(skb)->dccpd_ack_seq);
- if (unlikely(packet = NULL)) {
- DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
- "in history!\n", dccp_role(sk), sk,
- (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
- dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
- return;
- }
+ /* Update receive rate in units of 64 * bytes/second */
+ hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
+ hctx->ccid3hctx_x_recv <<= 6;
- /* Update receive rate in units of 64 * bytes/second */
- hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
- hctx->ccid3hctx_x_recv <<= 6;
+ /* Update loss event rate */
+ pinv = opt_recv->ccid3or_loss_event_rate;
+ if (pinv = ~0U || pinv = 0) /* see RFC 4342, 8.5 */
+ hctx->ccid3hctx_p = 0;
+ else /* can not exceed 100% */
+ hctx->ccid3hctx_p = 1000000 / pinv;
- /* Update loss event rate */
- pinv = opt_recv->ccid3or_loss_event_rate;
- if (pinv = ~0U || pinv = 0) /* see RFC 4342, 8.5 */
- hctx->ccid3hctx_p = 0;
- else /* can not exceed 100% */
- hctx->ccid3hctx_p = 1000000 / pinv;
+ /*
+ * Calculate new round trip sample as per [RFC 3448, 4.3] by
+ * R_sample = (t_now - t_recvdata) - t_elapsed
+ */
+ skb_get_timestamp(skb, &now);
+ r_sample = dccp_sample_rtt(sk, &now, &packet->dccphtx_tstamp);
- /*
- * Calculate new round trip sample as per [RFC 3448, 4.3] by
- * R_sample = (now - t_recvdata) - t_elapsed
- */
- skb_get_timestamp(skb, &now);
- r_sample = dccp_sample_rtt(sk, &now, &packet->dccphtx_tstamp);
+ /*
+ * Update RTT estimate (honours RTT from SYN exchange):
+ * If (No RTT sample so far)
+ * R = R_sample;
+ * Else
+ * R = q * R + (1 - q) * R_sample;
+ *
+ * q is a constant, RFC 3448 recommends 0.9
+ */
+ hctx->ccid3hctx_rtt = hctx->ccid3hctx_rtt = 0 ? r_sample
+ : (9 * hctx->ccid3hctx_rtt + r_sample) / 10;
+ if (hctx->ccid3hctx_state = TFRC_SSTATE_NO_FBACK) {
/*
- * Update RTT estimate (honours RTT from SYN exchange):
- * If (No RTT sample so far)
- * R = R_sample;
- * Else
- * R = q * R + (1 - q) * R_sample;
- *
- * q is a constant, RFC 3448 recomments 0.9
+ * Larger Initial Windows [RFC 4342, sec. 5]
*/
- hctx->ccid3hctx_rtt = hctx->ccid3hctx_rtt = 0 ? r_sample
- : (9 * hctx->ccid3hctx_rtt + r_sample) / 10;
+ hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
+ hctx->ccid3hctx_t_ld = now;
- if (hctx->ccid3hctx_state = TFRC_SSTATE_NO_FBACK) {
- /*
- * Larger Initial Windows [RFC 4342, sec. 5]
- */
- hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
- hctx->ccid3hctx_t_ld = now;
+ ccid3_update_send_interval(hctx);
- ccid3_update_send_interval(hctx);
+ ccid3_pr_debug("%s(%p), s=%u, MSS=%u, "
+ "R_sample=%uus, X=%u\n", dccp_role(sk),
+ sk, hctx->ccid3hctx_s,
+ dp->dccps_mss_cache, r_sample,
+ (unsigned)(hctx->ccid3hctx_x >> 6));
- ccid3_pr_debug("%s(%p), s=%u, MSS=%u, "
- "R_sample=%uus, X=%u\n", dccp_role(sk),
- sk, hctx->ccid3hctx_s,
- dp->dccps_mss_cache, r_sample,
- (unsigned)(hctx->ccid3hctx_x >> 6));
+ ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
+ } else {
- ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
- } else {
+ /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
+ if (hctx->ccid3hctx_p > 0)
+ hctx->ccid3hctx_x_calc + tfrc_calc_x(hctx->ccid3hctx_s,
+ hctx->ccid3hctx_rtt,
+ hctx->ccid3hctx_p);
+ ccid3_hc_tx_update_x(sk, &now);
- /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
- if (hctx->ccid3hctx_p > 0)
- hctx->ccid3hctx_x_calc - tfrc_calc_x(hctx->ccid3hctx_s,
- hctx->ccid3hctx_rtt,
- hctx->ccid3hctx_p);
- ccid3_hc_tx_update_x(sk, &now);
-
- ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
- "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
- dccp_role(sk),
- sk, hctx->ccid3hctx_rtt, r_sample,
- hctx->ccid3hctx_s, hctx->ccid3hctx_p,
- hctx->ccid3hctx_x_calc,
- (unsigned)(hctx->ccid3hctx_x_recv >> 6),
- (unsigned)(hctx->ccid3hctx_x >> 6));
- }
+ ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
+ "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
+ dccp_role(sk),
+ sk, hctx->ccid3hctx_rtt, r_sample,
+ hctx->ccid3hctx_s, hctx->ccid3hctx_p,
+ hctx->ccid3hctx_x_calc,
+ (unsigned)(hctx->ccid3hctx_x_recv >> 6),
+ (unsigned)(hctx->ccid3hctx_x >> 6));
+ }
- /* unschedule no feedback timer */
- sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
+ /* unschedule no feedback timer */
+ sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
- /* remove all packets older than the one acked from history */
- dccp_tx_hist_purge_older(ccid3_tx_hist,
- &hctx->ccid3hctx_hist, packet);
- /*
- * As we have calculated new ipi, delta, t_nom it is possible
- * that we now can send a packet, so wake up dccp_wait_for_ccid
- */
- sk->sk_write_space(sk);
+ /* remove all packets older than the one acked from history */
+ dccp_tx_hist_purge_older(ccid3_tx_hist,
+ &hctx->ccid3hctx_hist, packet);
+ /*
+ * As we have calculated new ipi, delta, t_nom it is possible
+ * that we now can send a packet, so wake up dccp_wait_for_ccid
+ */
+ sk->sk_write_space(sk);
- /*
- * Update timeout interval for the nofeedback timer.
- * We use a configuration option to increase the lower bound.
- * This can help avoid triggering the nofeedback timer too
- * often ('spinning') on LANs with small RTTs.
- */
- hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
- CONFIG_IP_DCCP_CCID3_RTO *
- (USEC_PER_SEC/1000));
- /*
- * Schedule no feedback timer to expire in
- * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
- */
- t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
+ /*
+ * Update timeout interval for the nofeedback timer.
+ * We use a configuration option to increase the lower bound.
+ * This can help avoid triggering the nofeedback timer too
+ * often ('spinning') on LANs with small RTTs.
+ */
+ hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
+ CONFIG_IP_DCCP_CCID3_RTO *
+ (USEC_PER_SEC/1000));
+ /*
+ * Schedule no feedback timer to expire in
+ * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
+ */
+ t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
- ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
- "expire in %lu jiffies (%luus)\n",
- dccp_role(sk),
- sk, usecs_to_jiffies(t_nfb), t_nfb);
+ sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
+ jiffies + usecs_to_jiffies(t_nfb));
- sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
- jiffies + usecs_to_jiffies(t_nfb));
+ ccid3_pr_debug("Scheduled no feedback timer to expire in %lu jiffies"
+ "(%luus)\n", usecs_to_jiffies(t_nfb), t_nfb);
- /* set idle flag */
- hctx->ccid3hctx_idle = 1;
- break;
- case TFRC_SSTATE_NO_SENT: /* fall through */
- case TFRC_SSTATE_TERM: /* ignore feedback when closing */
- break;
- }
+ /* set idle flag */
+ hctx->ccid3hctx_idle = 1;
}
static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
--
1.5.0.6
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