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[CCID3]: Handle Idle and Application-Limited periods 

This updates the code with regard to handling idle and application-limited
periods as specified in [RFC 4342, 5.1].

Background:
This commit is contained in:
Gerrit Renker 2007-03-20 15:19:07 -03:00 committed by David S. Miller
parent a21f9f96cd
commit 0c150efb28
1 changed files with 39 additions and 43 deletions
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82
net/dccp/ccids/ccid3.c
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@ -133,12 +133,23 @@ static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
__u64 min_rate = 2 * hctx->ccid3hctx_x_recv;
const __u64 old_x = hctx->ccid3hctx_x;
/*
* Handle IDLE periods: do not reduce below RFC3390 initial sending rate
* when idling [RFC 4342, 5.1]. See also draft-ietf-dccp-rfc3448bis.
* For consistency with X and X_recv, min_rate is also scaled by 2^6.
*/
if (unlikely(hctx->ccid3hctx_idle)) {
min_rate = rfc3390_initial_rate(sk);
min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv);
}
if (hctx->ccid3hctx_p > 0) {
hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
hctx->ccid3hctx_x_recv * 2);
min_rate);
hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
(((__u64)hctx->ccid3hctx_s) << 6) /
TFRC_T_MBI);
@ -147,7 +158,7 @@ static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
(suseconds_t)hctx->ccid3hctx_rtt >= 0) {
hctx->ccid3hctx_x =
max(2 * min(hctx->ccid3hctx_x, hctx->ccid3hctx_x_recv),
max(min(2 * hctx->ccid3hctx_x, min_rate),
scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
hctx->ccid3hctx_rtt));
hctx->ccid3hctx_t_ld = *now;
@ -209,6 +220,7 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
{
struct sock *sk = (struct sock *)data;
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
struct timeval now;
unsigned long t_nfb = USEC_PER_SEC / 5;
bh_lock_sock(sk);
@ -221,6 +233,8 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state));
hctx->ccid3hctx_idle = 1;
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_FBACK:
/* RFC 3448, 4.4: Halve send rate directly */
@ -239,49 +253,33 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
break;
case TFRC_SSTATE_FBACK:
/*
* Check if IDLE since last timeout and recv rate is less than
* 4 packets (in units of 64*bytes/sec) per RTT
* Modify the cached value of X_recv [RFC 3448, 4.4]
*
* If (p == 0 || X_calc > 2 * X_recv)
* X_recv = max(X_recv / 2, s / (2 * t_mbi));
* Else
* X_recv = X_calc / 4;
*
* Note that X_recv is scaled by 2^6 while X_calc is not
*/
if (!hctx->ccid3hctx_idle ||
(hctx->ccid3hctx_x_recv >= 4 *
scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
hctx->ccid3hctx_rtt))) {
struct timeval now;
BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
ccid3_pr_debug("%s(%p, state=%s), not idle\n",
dccp_role(sk), sk,
ccid3_tx_state_name(hctx->ccid3hctx_state));
if (hctx->ccid3hctx_p == 0 ||
(hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5))) {
/*
* Modify the cached value of X_recv [RFC 3448, 4.4]
*
* If (p == 0 || X_calc > 2 * X_recv)
* X_recv = max(X_recv / 2, s / (2 * t_mbi));
* Else
* X_recv = X_calc / 4;
*
* Note that X_recv is scaled by 2^6 while X_calc is not
*/
BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
hctx->ccid3hctx_x_recv =
max(hctx->ccid3hctx_x_recv / 2,
(((__u64)hctx->ccid3hctx_s) << 6) /
(2 * TFRC_T_MBI));
if (hctx->ccid3hctx_p == 0 ||
(hctx->ccid3hctx_x_calc >
(hctx->ccid3hctx_x_recv >> 5))) {
hctx->ccid3hctx_x_recv =
max(hctx->ccid3hctx_x_recv / 2,
(((__u64)hctx->ccid3hctx_s) << 6) /
(2 * TFRC_T_MBI));
if (hctx->ccid3hctx_p == 0)
dccp_timestamp(sk, &now);
} else {
hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
hctx->ccid3hctx_x_recv <<= 4;
}
/* Now recalculate X [RFC 3448, 4.3, step (4)] */
ccid3_hc_tx_update_x(sk, &now);
if (hctx->ccid3hctx_p == 0)
dccp_timestamp(sk, &now);
} else {
hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
hctx->ccid3hctx_x_recv <<= 4;
}
/* Now recalculate X [RFC 3448, 4.3, step (4)] */
ccid3_hc_tx_update_x(sk, &now);
/*
* Schedule no feedback timer to expire in
* max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
@ -296,8 +294,6 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
goto out;
}
hctx->ccid3hctx_idle = 1;
restart_timer:
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
jiffies + usecs_to_jiffies(t_nfb));
@ -377,6 +373,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
/* prepare to send now (add options etc.) */
dp->dccps_hc_tx_insert_options = 1;
DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
hctx->ccid3hctx_idle = 0;
/* set the nominal send time for the next following packet */
timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
@ -407,7 +404,6 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
packet->dccphtx_sent = 1;
hctx->ccid3hctx_idle = 0;
}
static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)