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Diffstat (limited to 'net/dccp/ccids/ccid3.c')
-rw-r--r--net/dccp/ccids/ccid3.c119
1 files changed, 65 insertions, 54 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 70ebe705eb7..cf8c07b2704 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -121,12 +121,15 @@ static inline void ccid3_update_send_time(struct ccid3_hc_tx_sock *hctx)
/*
* Update X by
* If (p > 0)
- * x_calc = calcX(s, R, p);
+ * X_calc = calcX(s, R, p);
* X = max(min(X_calc, 2 * X_recv), s / t_mbi);
* Else
* If (now - tld >= R)
* X = max(min(2 * X, 2 * X_recv), s / R);
* tld = now;
+ *
+ * If X has changed, we also update the scheduled send time t_now,
+ * the inter-packet interval t_ipi, and the delta value.
*/
static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
@@ -134,8 +137,7 @@ static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
const __u32 old_x = hctx->ccid3hctx_x;
- /* To avoid large error in calcX */
- if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) {
+ if (hctx->ccid3hctx_p > 0) {
hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s,
hctx->ccid3hctx_rtt,
hctx->ccid3hctx_p);
@@ -223,16 +225,14 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
ccid3_tx_state_name(hctx->ccid3hctx_state));
/* Halve sending rate */
- /* If (X_calc > 2 * X_recv)
+ /* If (p == 0 || X_calc > 2 * X_recv)
* X_recv = max(X_recv / 2, s / (2 * t_mbi));
* Else
* X_recv = X_calc / 4;
*/
- BUG_ON(hctx->ccid3hctx_p >= TFRC_SMALLEST_P &&
- hctx->ccid3hctx_x_calc == 0);
+ BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
- /* check also if p is zero -> x_calc is infinity? */
- if (hctx->ccid3hctx_p < TFRC_SMALLEST_P ||
+ if (hctx->ccid3hctx_p == 0 ||
hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv)
hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2,
hctx->ccid3hctx_s / (2 * TFRC_T_MBI));
@@ -245,9 +245,10 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
}
/*
* Schedule no feedback timer to expire in
- * max(4 * R, 2 * s/X) = max(4 * R, 2 * t_ipi)
+ * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
+ * See comments in packet_recv() regarding the value of t_RTO.
*/
- t_nfb = max(4 * hctx->ccid3hctx_rtt, 2 * hctx->ccid3hctx_t_ipi);
+ t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
break;
case TFRC_SSTATE_NO_SENT:
DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
@@ -338,7 +339,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
* else
* // send the packet in (t_nom - t_now) milliseconds.
*/
- if (delay >= hctx->ccid3hctx_delta)
+ if (delay - (long)hctx->ccid3hctx_delta >= 0)
return delay / 1000L;
break;
case TFRC_SSTATE_TERM:
@@ -412,10 +413,8 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
struct dccp_tx_hist_entry *packet;
struct timeval now;
unsigned long t_nfb;
- u32 t_elapsed;
u32 pinv;
- u32 x_recv;
- u32 r_sample;
+ long r_sample, t_elapsed;
BUG_ON(hctx == NULL);
@@ -426,31 +425,44 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
opt_recv = &hctx->ccid3hctx_options_received;
- t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
- x_recv = opt_recv->ccid3or_receive_rate;
- pinv = opt_recv->ccid3or_loss_event_rate;
-
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
- /* Calculate new round trip sample by
- * R_sample = (now - t_recvdata) - t_delay */
- /* get t_recvdata from history */
+ /* 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, sk=%p, seqno %llu(%s) does't exist "
+ 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 RTT */
+ /* Update receive rate */
+ hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
+
+ /* Update loss event rate */
+ pinv = opt_recv->ccid3or_loss_event_rate;
+ if (pinv == ~0U || pinv == 0)
+ hctx->ccid3hctx_p = 0;
+ else
+ hctx->ccid3hctx_p = 1000000 / pinv;
+
dccp_timestamp(sk, &now);
- r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
- if (unlikely(r_sample <= t_elapsed))
- DCCP_WARN("r_sample=%uus,t_elapsed=%uus\n",
+
+ /*
+ * Calculate new round trip sample as per [RFC 3448, 4.3] by
+ * R_sample = (now - t_recvdata) - t_elapsed
+ */
+ r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
+ t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
+
+ if (unlikely(r_sample <= 0)) {
+ DCCP_WARN("WARNING: R_sample (%ld) <= 0!\n", r_sample);
+ r_sample = 0;
+ } else if (unlikely(r_sample <= t_elapsed))
+ DCCP_WARN("WARNING: r_sample=%ldus <= t_elapsed=%ldus\n",
r_sample, t_elapsed);
else
r_sample -= t_elapsed;
@@ -473,31 +485,25 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
hctx->ccid3hctx_t_ld = now;
ccid3_update_send_time(hctx);
- ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
- } else {
- hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
- r_sample / 10;
- ccid3_hc_tx_update_x(sk, &now);
- }
- ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
- "r_sample=%us\n", dccp_role(sk), sk,
- hctx->ccid3hctx_rtt, r_sample);
+ ccid3_pr_debug("%s(%p), s=%u, w_init=%u, "
+ "R_sample=%ldus, X=%u\n", dccp_role(sk),
+ sk, hctx->ccid3hctx_s, w_init, r_sample,
+ hctx->ccid3hctx_x);
- /* Update receive rate */
- hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
+ ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
+ } else {
+ hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
+ (u32)r_sample ) / 10;
- /* Update loss event rate */
- if (pinv == ~0 || pinv == 0)
- hctx->ccid3hctx_p = 0;
- else {
- hctx->ccid3hctx_p = 1000000 / pinv;
+ ccid3_hc_tx_update_x(sk, &now);
- if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
- hctx->ccid3hctx_p = TFRC_SMALLEST_P;
- ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
- dccp_role(sk), sk);
- }
+ ccid3_pr_debug("%s(%p), RTT=%uus (sample=%ldus), s=%u, "
+ "p=%u, X_calc=%u, X=%u\n", dccp_role(sk),
+ sk, hctx->ccid3hctx_rtt, r_sample,
+ hctx->ccid3hctx_s, hctx->ccid3hctx_p,
+ hctx->ccid3hctx_x_calc,
+ hctx->ccid3hctx_x);
}
/* unschedule no feedback timer */
@@ -512,16 +518,20 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
*/
sk->sk_write_space(sk);
- /* Update timeout interval. We use the alternative variant of
- * [RFC 3448, 3.1] which sets the upper bound of t_rto to one
- * second, as it is suggested for TCP (see RFC 2988, 2.4). */
+ /*
+ * 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,
- USEC_PER_SEC );
+ CONFIG_IP_DCCP_CCID3_RTO *
+ (USEC_PER_SEC/1000) );
/*
* Schedule no feedback timer to expire in
- * max(4 * R, 2 * s/X) = max(4 * R, 2 * t_ipi)
+ * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
*/
- t_nfb = max(4 * hctx->ccid3hctx_rtt, 2 * hctx->ccid3hctx_t_ipi);
+ t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
"expire in %lu jiffies (%luus)\n",
@@ -535,7 +545,8 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
hctx->ccid3hctx_idle = 1;
break;
case TFRC_SSTATE_NO_SENT:
- DCCP_WARN("Illegal ACK received - no packet has been sent\n");
+ if (dccp_sk(sk)->dccps_role == DCCP_ROLE_CLIENT)
+ DCCP_WARN("Illegal ACK received - no packet sent\n");
/* fall through */
case TFRC_SSTATE_TERM: /* ignore feedback when closing */
break;
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-26 08:05:15 +0000