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[CCID3]: Remove two irrelevant states in TX feedback handling
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 * the NO_SENT state is only triggered in bidirectional mode,
   costing unnecessary processing.
 * the TERM (terminating) state is irrelevant.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Gerrit Renker authored and David S. Miller committed Jan 28, 2008
1 parent 8e138e7 commit 5bd370a
Showing 1 changed file with 84 additions and 89 deletions.
173 changes: 84 additions & 89 deletions net/dccp/ccids/ccid3.c
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Original file line number Diff line number Diff line change
Expand Up @@ -402,112 +402,107 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
return;
/* ... and only in the established state */
if (hctx->ccid3hctx_state != TFRC_SSTATE_FBACK &&
hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
return;

opt_recv = &hctx->ccid3hctx_options_received;
now = ktime_get_real();

switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
now = ktime_get_real();

/* estimate RTT from history if ACK number is valid */
r_sample = tfrc_tx_hist_rtt(hctx->ccid3hctx_hist,
DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
if (r_sample == 0) {
DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
return;
}
/* Estimate RTT from history if ACK number is valid */
r_sample = tfrc_tx_hist_rtt(hctx->ccid3hctx_hist,
DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
if (r_sample == 0) {
DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
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 (which is scaled by 1e6) */
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;
/*
* Validate new RTT sample and update moving average
*/
r_sample = dccp_sample_rtt(sk, r_sample);
hctx->ccid3hctx_rtt = tfrc_ewma(hctx->ccid3hctx_rtt, r_sample, 9);

/* 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;
if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
/*
* Validate new RTT sample and update moving average
* Larger Initial Windows [RFC 4342, sec. 5]
*/
r_sample = dccp_sample_rtt(sk, r_sample);
hctx->ccid3hctx_rtt = tfrc_ewma(hctx->ccid3hctx_rtt, r_sample, 9);
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,
dccp_sk(sk)->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,
dccp_sk(sk)->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);

/*
* 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);
/*
* 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);
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));
break;
case TFRC_SSTATE_NO_SENT: /* fall through */
case TFRC_SSTATE_TERM: /* ignore feedback when closing */
break;
}
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + usecs_to_jiffies(t_nfb));
}

static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
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