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[CCID3]: Implement rfc3448bis changes to feedback reception 

This implements the algorithm to update the allowed sending rate X upon
receiving feedback packets, as described in draft rfc3448bis, 4.2/4.3.

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>
This commit is contained in:
Gerrit Renker 2007-12-17 12:48:47 -02:00 committed by David S. Miller
parent 5bd370a63d
commit d8d1252f74
1 changed files with 28 additions and 23 deletions
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51
net/dccp/ccids/ccid3.c
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@ -429,40 +429,46 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
hctx->ccid3hctx_p = 0;
else /* can not exceed 100% */
hctx->ccid3hctx_p = 1000000 / pinv;
hctx->ccid3hctx_p = scaled_div(1, 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 allowed sending rate X as per draft rfc3448bis-00, 4.2/3
*/
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_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 {
/* Update sending rate (step 4 of [RFC 3448, 4.3]) */
if (hctx->ccid3hctx_p > 0)
hctx->ccid3hctx_x_calc =
if (hctx->ccid3hctx_t_rto == 0) {
/*
* Initial feedback packet: Larger Initial Windows (4.2)
*/
hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
hctx->ccid3hctx_t_ld = now;
ccid3_update_send_interval(hctx);
goto done_computing_x;
} else if (hctx->ccid3hctx_p == 0) {
/*
* First feedback after nofeedback timer expiry (4.3)
*/
goto done_computing_x;
}
}
/* 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_hc_tx_update_x(sk, &now);
ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
done_computing_x:
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,
@ -470,7 +476,6 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
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);