2 * net/dccp/ccids/ccid3.c
4 * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
5 * Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
7 * An implementation of the DCCP protocol
9 * This code has been developed by the University of Waikato WAND
10 * research group. For further information please see http://www.wand.net.nz/
12 * This code also uses code from Lulea University, rereleased as GPL by its
14 * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
16 * Changes to meet Linux coding standards, to make it meet latest ccid3 draft
17 * and to make it work as a loadable module in the DCCP stack written by
18 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
20 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
22 * This program is free software; you can redistribute it and/or modify
23 * it under the terms of the GNU General Public License as published by
24 * the Free Software Foundation; either version 2 of the License, or
25 * (at your option) any later version.
27 * This program is distributed in the hope that it will be useful,
28 * but WITHOUT ANY WARRANTY; without even the implied warranty of
29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
30 * GNU General Public License for more details.
32 * You should have received a copy of the GNU General Public License
33 * along with this program; if not, write to the Free Software
34 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
39 #include "lib/packet_history.h"
40 #include "lib/loss_interval.h"
45 * Reason for maths here is to avoid 32 bit overflow when a is big.
46 * With this we get close to the limit.
48 static u32 usecs_div(const u32 a, const u32 b)
50 const u32 div = a < (UINT_MAX / (USEC_PER_SEC / 10)) ? 10 :
51 a < (UINT_MAX / (USEC_PER_SEC / 50)) ? 50 :
52 a < (UINT_MAX / (USEC_PER_SEC / 100)) ? 100 :
53 a < (UINT_MAX / (USEC_PER_SEC / 500)) ? 500 :
54 a < (UINT_MAX / (USEC_PER_SEC / 1000)) ? 1000 :
55 a < (UINT_MAX / (USEC_PER_SEC / 5000)) ? 5000 :
56 a < (UINT_MAX / (USEC_PER_SEC / 10000)) ? 10000 :
57 a < (UINT_MAX / (USEC_PER_SEC / 50000)) ? 50000 :
59 const u32 tmp = a * (USEC_PER_SEC / div);
60 return (b >= 2 * div) ? tmp / (b / div) : tmp;
65 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
66 static int ccid3_debug;
67 #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
69 #define ccid3_pr_debug(format, a...)
72 static struct dccp_tx_hist *ccid3_tx_hist;
73 static struct dccp_rx_hist *ccid3_rx_hist;
74 static struct dccp_li_hist *ccid3_li_hist;
76 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
77 static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
79 static char *ccid3_state_names[] = {
80 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
81 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
82 [TFRC_SSTATE_FBACK] = "FBACK",
83 [TFRC_SSTATE_TERM] = "TERM",
86 return ccid3_state_names[state];
90 static void ccid3_hc_tx_set_state(struct sock *sk,
91 enum ccid3_hc_tx_states state)
93 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
94 enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
96 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
97 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
98 ccid3_tx_state_name(state));
99 WARN_ON(state == oldstate);
100 hctx->ccid3hctx_state = state;
103 /* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */
104 static inline void ccid3_calc_new_t_ipi(struct ccid3_hc_tx_sock *hctx)
106 hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_x);
109 /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
110 static inline void ccid3_calc_new_delta(struct ccid3_hc_tx_sock *hctx)
112 hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
113 TFRC_OPSYS_HALF_TIME_GRAN);
119 * x_calc = calcX(s, R, p);
120 * X = max(min(X_calc, 2 * X_recv), s / t_mbi);
122 * If (now - tld >= R)
123 * X = max(min(2 * X, 2 * X_recv), s / R);
126 static void ccid3_hc_tx_update_x(struct sock *sk)
128 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
130 /* To avoid large error in calcX */
131 if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) {
132 hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s,
135 hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_calc,
136 2 * hctx->ccid3hctx_x_recv),
138 TFRC_MAX_BACK_OFF_TIME));
142 dccp_timestamp(sk, &now);
143 if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >=
144 hctx->ccid3hctx_rtt) {
145 hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_recv,
146 hctx->ccid3hctx_x) * 2,
147 usecs_div(hctx->ccid3hctx_s,
148 hctx->ccid3hctx_rtt));
149 hctx->ccid3hctx_t_ld = now;
154 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
156 struct sock *sk = (struct sock *)data;
157 unsigned long next_tmout = 0;
158 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
161 if (sock_owned_by_user(sk)) {
162 /* Try again later. */
163 /* XXX: set some sensible MIB */
164 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
169 ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
170 ccid3_tx_state_name(hctx->ccid3hctx_state));
172 switch (hctx->ccid3hctx_state) {
173 case TFRC_SSTATE_NO_FBACK:
174 /* Halve send rate */
175 hctx->ccid3hctx_x /= 2;
176 if (hctx->ccid3hctx_x < (hctx->ccid3hctx_s /
177 TFRC_MAX_BACK_OFF_TIME))
178 hctx->ccid3hctx_x = (hctx->ccid3hctx_s /
179 TFRC_MAX_BACK_OFF_TIME);
181 ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %d "
184 ccid3_tx_state_name(hctx->ccid3hctx_state),
186 next_tmout = max_t(u32, 2 * usecs_div(hctx->ccid3hctx_s,
188 TFRC_INITIAL_TIMEOUT);
190 * FIXME - not sure above calculation is correct. See section
191 * 5 of CCID3 11 should adjust tx_t_ipi and double that to
195 case TFRC_SSTATE_FBACK:
197 * Check if IDLE since last timeout and recv rate is less than
200 if (!hctx->ccid3hctx_idle ||
201 (hctx->ccid3hctx_x_recv >=
202 4 * usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt))) {
203 ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
205 ccid3_tx_state_name(hctx->ccid3hctx_state));
206 /* Halve sending rate */
208 /* If (X_calc > 2 * X_recv)
209 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
211 * X_recv = X_calc / 4;
213 BUG_ON(hctx->ccid3hctx_p >= TFRC_SMALLEST_P &&
214 hctx->ccid3hctx_x_calc == 0);
216 /* check also if p is zero -> x_calc is infinity? */
217 if (hctx->ccid3hctx_p < TFRC_SMALLEST_P ||
218 hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv)
219 hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2,
220 hctx->ccid3hctx_s / (2 * TFRC_MAX_BACK_OFF_TIME));
222 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc / 4;
224 /* Update sending rate */
225 ccid3_hc_tx_update_x(sk);
228 * Schedule no feedback timer to expire in
229 * max(4 * R, 2 * s / X)
231 next_tmout = max_t(u32, hctx->ccid3hctx_t_rto,
232 2 * usecs_div(hctx->ccid3hctx_s,
235 case TFRC_SSTATE_NO_SENT:
236 DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
238 case TFRC_SSTATE_TERM:
242 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
243 jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
244 hctx->ccid3hctx_idle = 1;
252 * > 0: delay (in msecs) that should pass before actually sending
253 * = 0: can send immediately
254 * < 0: error condition; do not send packet
256 static int ccid3_hc_tx_send_packet(struct sock *sk,
257 struct sk_buff *skb, int len)
259 struct dccp_sock *dp = dccp_sk(sk);
260 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
261 struct dccp_tx_hist_entry *new_packet;
265 BUG_ON(hctx == NULL);
268 * This function is called only for Data and DataAck packets. Sending
269 * zero-sized Data(Ack)s is theoretically possible, but for congestion
270 * control this case is pathological - ignore it.
272 if (unlikely(len == 0))
275 /* See if last packet allocated was not sent */
276 new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
277 if (new_packet == NULL || new_packet->dccphtx_sent) {
278 new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
281 if (unlikely(new_packet == NULL)) {
282 DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
283 "send refused\n", dccp_role(sk), sk);
287 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
290 dccp_timestamp(sk, &now);
292 switch (hctx->ccid3hctx_state) {
293 case TFRC_SSTATE_NO_SENT:
294 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
295 jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
296 hctx->ccid3hctx_last_win_count = 0;
297 hctx->ccid3hctx_t_last_win_count = now;
298 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
300 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
301 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
302 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
303 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
305 /* Set t_0 for initial packet */
306 hctx->ccid3hctx_t_nom = now;
308 case TFRC_SSTATE_NO_FBACK:
309 case TFRC_SSTATE_FBACK:
310 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
312 * Scheduling of packet transmissions [RFC 3448, 4.6]
314 * if (t_now > t_nom - delta)
315 * // send the packet now
317 * // send the packet in (t_nom - t_now) milliseconds.
319 if (delay >= hctx->ccid3hctx_delta)
320 return delay / 1000L;
322 case TFRC_SSTATE_TERM:
323 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
327 /* prepare to send now (add options etc.) */
328 dp->dccps_hc_tx_insert_options = 1;
329 new_packet->dccphtx_ccval = DCCP_SKB_CB(skb)->dccpd_ccval =
330 hctx->ccid3hctx_last_win_count;
331 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
336 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
338 const struct dccp_sock *dp = dccp_sk(sk);
339 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
342 BUG_ON(hctx == NULL);
344 dccp_timestamp(sk, &now);
346 /* check if we have sent a data packet */
348 unsigned long quarter_rtt;
349 struct dccp_tx_hist_entry *packet;
351 packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
352 if (unlikely(packet == NULL)) {
353 DCCP_WARN("packet doesn't exist in history!\n");
356 if (unlikely(packet->dccphtx_sent)) {
357 DCCP_WARN("no unsent packet in history!\n");
360 packet->dccphtx_tstamp = now;
361 packet->dccphtx_seqno = dp->dccps_gss;
363 * Check if win_count have changed
364 * Algorithm in "8.1. Window Counter Value" in RFC 4342.
366 quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
367 if (likely(hctx->ccid3hctx_rtt > 8))
368 quarter_rtt /= hctx->ccid3hctx_rtt / 4;
370 if (quarter_rtt > 0) {
371 hctx->ccid3hctx_t_last_win_count = now;
372 hctx->ccid3hctx_last_win_count = (hctx->ccid3hctx_last_win_count +
373 min_t(unsigned long, quarter_rtt, 5)) % 16;
374 ccid3_pr_debug("%s, sk=%p, window changed from "
377 packet->dccphtx_ccval,
378 hctx->ccid3hctx_last_win_count);
381 hctx->ccid3hctx_idle = 0;
382 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
383 packet->dccphtx_sent = 1;
385 ccid3_pr_debug("%s, sk=%p, seqno=%llu NOT inserted!\n",
386 dccp_role(sk), sk, dp->dccps_gss);
388 switch (hctx->ccid3hctx_state) {
389 case TFRC_SSTATE_NO_SENT:
391 case TFRC_SSTATE_NO_FBACK:
392 /* t_nom, t_ipi, delta do not change until feedback arrives */
394 case TFRC_SSTATE_FBACK:
396 timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
397 hctx->ccid3hctx_t_ipi);
398 ccid3_calc_new_t_ipi(hctx);
399 ccid3_calc_new_delta(hctx);
400 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
401 hctx->ccid3hctx_t_ipi);
404 case TFRC_SSTATE_TERM:
405 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
410 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
412 const struct dccp_sock *dp = dccp_sk(sk);
413 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
414 struct ccid3_options_received *opt_recv;
415 struct dccp_tx_hist_entry *packet;
417 unsigned long next_tmout;
423 BUG_ON(hctx == NULL);
425 /* we are only interested in ACKs */
426 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
427 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
430 opt_recv = &hctx->ccid3hctx_options_received;
432 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
433 x_recv = opt_recv->ccid3or_receive_rate;
434 pinv = opt_recv->ccid3or_loss_event_rate;
436 switch (hctx->ccid3hctx_state) {
437 case TFRC_SSTATE_NO_SENT:
438 /* FIXME: what to do here? */
440 case TFRC_SSTATE_NO_FBACK:
441 case TFRC_SSTATE_FBACK:
442 /* Calculate new round trip sample by
443 * R_sample = (now - t_recvdata) - t_delay */
444 /* get t_recvdata from history */
445 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
446 DCCP_SKB_CB(skb)->dccpd_ack_seq);
447 if (unlikely(packet == NULL)) {
448 DCCP_WARN("%s, sk=%p, seqno %llu(%s) does't exist "
449 "in history!\n", dccp_role(sk), sk,
450 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
451 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
456 dccp_timestamp(sk, &now);
457 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
458 if (unlikely(r_sample <= t_elapsed))
459 DCCP_WARN("r_sample=%uus,t_elapsed=%uus\n",
460 r_sample, t_elapsed);
462 r_sample -= t_elapsed;
464 /* Update RTT estimate by
465 * If (No feedback recv)
468 * R = q * R + (1 - q) * R_sample;
470 * q is a constant, RFC 3448 recomments 0.9
472 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
473 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
474 hctx->ccid3hctx_rtt = r_sample;
476 hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
479 ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
480 "r_sample=%us\n", dccp_role(sk), sk,
481 hctx->ccid3hctx_rtt, r_sample);
483 /* Update timeout interval */
484 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
487 /* Update receive rate */
488 hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
490 /* Update loss event rate */
491 if (pinv == ~0 || pinv == 0)
492 hctx->ccid3hctx_p = 0;
494 hctx->ccid3hctx_p = 1000000 / pinv;
496 if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
497 hctx->ccid3hctx_p = TFRC_SMALLEST_P;
498 ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
503 /* unschedule no feedback timer */
504 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
506 /* Update sending rate */
507 ccid3_hc_tx_update_x(sk);
509 /* Update next send time */
510 timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
511 hctx->ccid3hctx_t_ipi);
512 ccid3_calc_new_t_ipi(hctx);
513 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
514 hctx->ccid3hctx_t_ipi);
515 ccid3_calc_new_delta(hctx);
517 /* remove all packets older than the one acked from history */
518 dccp_tx_hist_purge_older(ccid3_tx_hist,
519 &hctx->ccid3hctx_hist, packet);
521 * As we have calculated new ipi, delta, t_nom it is possible that
522 * we now can send a packet, so wake up dccp_wait_for_ccids.
524 sk->sk_write_space(sk);
527 * Schedule no feedback timer to expire in
528 * max(4 * R, 2 * s / X)
530 next_tmout = max(hctx->ccid3hctx_t_rto,
531 2 * usecs_div(hctx->ccid3hctx_s,
534 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
535 "expire in %lu jiffies (%luus)\n",
537 usecs_to_jiffies(next_tmout), next_tmout);
539 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
540 jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
543 hctx->ccid3hctx_idle = 1;
545 case TFRC_SSTATE_TERM:
546 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
551 static int ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
553 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
555 BUG_ON(hctx == NULL);
557 if (sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)
558 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
562 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
563 unsigned char len, u16 idx,
564 unsigned char *value)
567 const struct dccp_sock *dp = dccp_sk(sk);
568 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
569 struct ccid3_options_received *opt_recv;
571 BUG_ON(hctx == NULL);
573 opt_recv = &hctx->ccid3hctx_options_received;
575 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
576 opt_recv->ccid3or_seqno = dp->dccps_gsr;
577 opt_recv->ccid3or_loss_event_rate = ~0;
578 opt_recv->ccid3or_loss_intervals_idx = 0;
579 opt_recv->ccid3or_loss_intervals_len = 0;
580 opt_recv->ccid3or_receive_rate = 0;
584 case TFRC_OPT_LOSS_EVENT_RATE:
585 if (unlikely(len != 4)) {
586 DCCP_WARN("%s, sk=%p, invalid len %d "
587 "for TFRC_OPT_LOSS_EVENT_RATE\n",
588 dccp_role(sk), sk, len);
591 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
592 ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
594 opt_recv->ccid3or_loss_event_rate);
597 case TFRC_OPT_LOSS_INTERVALS:
598 opt_recv->ccid3or_loss_intervals_idx = idx;
599 opt_recv->ccid3or_loss_intervals_len = len;
600 ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
602 opt_recv->ccid3or_loss_intervals_idx,
603 opt_recv->ccid3or_loss_intervals_len);
605 case TFRC_OPT_RECEIVE_RATE:
606 if (unlikely(len != 4)) {
607 DCCP_WARN("%s, sk=%p, invalid len %d "
608 "for TFRC_OPT_RECEIVE_RATE\n",
609 dccp_role(sk), sk, len);
612 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
613 ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
615 opt_recv->ccid3or_receive_rate);
623 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
625 struct dccp_sock *dp = dccp_sk(sk);
626 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
628 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
629 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
630 hctx->ccid3hctx_s = dp->dccps_packet_size;
632 hctx->ccid3hctx_s = TFRC_STD_PACKET_SIZE;
634 /* Set transmission rate to 1 packet per second */
635 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
636 hctx->ccid3hctx_t_rto = USEC_PER_SEC;
637 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
638 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
640 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
641 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
642 init_timer(&hctx->ccid3hctx_no_feedback_timer);
647 static void ccid3_hc_tx_exit(struct sock *sk)
649 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
651 BUG_ON(hctx == NULL);
653 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
654 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
656 /* Empty packet history */
657 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
661 * RX Half Connection methods
664 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
665 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
667 static char *ccid3_rx_state_names[] = {
668 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
669 [TFRC_RSTATE_DATA] = "DATA",
670 [TFRC_RSTATE_TERM] = "TERM",
673 return ccid3_rx_state_names[state];
677 static void ccid3_hc_rx_set_state(struct sock *sk,
678 enum ccid3_hc_rx_states state)
680 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
681 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
683 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
684 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
685 ccid3_rx_state_name(state));
686 WARN_ON(state == oldstate);
687 hcrx->ccid3hcrx_state = state;
690 static void ccid3_hc_rx_send_feedback(struct sock *sk)
692 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
693 struct dccp_sock *dp = dccp_sk(sk);
694 struct dccp_rx_hist_entry *packet;
697 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
699 dccp_timestamp(sk, &now);
701 switch (hcrx->ccid3hcrx_state) {
702 case TFRC_RSTATE_NO_DATA:
703 hcrx->ccid3hcrx_x_recv = 0;
705 case TFRC_RSTATE_DATA: {
706 const u32 delta = timeval_delta(&now,
707 &hcrx->ccid3hcrx_tstamp_last_feedback);
708 hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
712 case TFRC_RSTATE_TERM:
713 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
717 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
718 if (unlikely(packet == NULL)) {
719 DCCP_WARN("%s, sk=%p, no data packet in history!\n",
724 hcrx->ccid3hcrx_tstamp_last_feedback = now;
725 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
726 hcrx->ccid3hcrx_bytes_recv = 0;
728 /* Convert to multiples of 10us */
729 hcrx->ccid3hcrx_elapsed_time =
730 timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
731 if (hcrx->ccid3hcrx_p == 0)
732 hcrx->ccid3hcrx_pinv = ~0;
734 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
735 dp->dccps_hc_rx_insert_options = 1;
739 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
741 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
744 BUG_ON(hcrx == NULL);
746 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
749 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
751 if (dccp_packet_without_ack(skb))
754 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
755 pinv = htonl(hcrx->ccid3hcrx_pinv);
757 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
758 dccp_insert_option_elapsed_time(sk, skb,
759 hcrx->ccid3hcrx_elapsed_time)) ||
760 dccp_insert_option_timestamp(sk, skb) ||
761 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
762 &pinv, sizeof(pinv)) ||
763 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
764 &x_recv, sizeof(x_recv)))
770 /* calculate first loss interval
772 * returns estimated loss interval in usecs */
774 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
776 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
777 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
778 u32 rtt, delta, x_recv, fval, p, tmp2;
779 struct timeval tstamp = { 0, };
785 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
787 if (dccp_rx_hist_entry_data_packet(entry)) {
792 tstamp = entry->dccphrx_tstamp;
793 win_count = entry->dccphrx_ccval;
797 interval = win_count - entry->dccphrx_ccval;
799 interval += TFRC_WIN_COUNT_LIMIT;
807 if (unlikely(step == 0)) {
808 DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
813 if (unlikely(interval == 0)) {
814 DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
815 "Defaulting to 1\n", dccp_role(sk), sk);
820 DCCP_CRIT("tail is null\n");
823 rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
824 ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
825 dccp_role(sk), sk, rtt);
828 DCCP_WARN("RTT==0, setting to 1\n");
832 dccp_timestamp(sk, &tstamp);
833 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
834 x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);
837 x_recv = hcrx->ccid3hcrx_x_recv;
839 tmp1 = (u64)x_recv * (u64)rtt;
840 do_div(tmp1,10000000);
844 DCCP_CRIT("tmp2 = 0, x_recv = %u, rtt =%u\n", x_recv, rtt);
848 fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
849 /* do not alter order above or you will get overflow on 32 bit */
850 p = tfrc_calc_x_reverse_lookup(fval);
851 ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
852 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
860 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
862 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
863 struct dccp_li_hist_entry *head;
866 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
867 if (!dccp_li_hist_interval_new(ccid3_li_hist,
868 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
871 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
872 struct dccp_li_hist_entry, dccplih_node);
873 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
875 struct dccp_li_hist_entry *entry;
876 struct list_head *tail;
878 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
879 struct dccp_li_hist_entry, dccplih_node);
880 /* FIXME win count check removed as was wrong */
881 /* should make this check with receive history */
882 /* and compare there as per section 10.2 of RFC4342 */
884 /* new loss event detected */
885 /* calculate last interval length */
886 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
887 entry = dccp_li_hist_entry_new(ccid3_li_hist, SLAB_ATOMIC);
890 DCCP_BUG("out of memory - can not allocate entry");
894 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
896 tail = hcrx->ccid3hcrx_li_hist.prev;
898 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
900 /* Create the newest interval */
901 entry->dccplih_seqno = seq_loss;
902 entry->dccplih_interval = seq_temp;
903 entry->dccplih_win_count = win_loss;
907 static int ccid3_hc_rx_detect_loss(struct sock *sk,
908 struct dccp_rx_hist_entry *packet)
910 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
911 struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
912 u64 seqno = packet->dccphrx_seqno;
918 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
921 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
922 hcrx->ccid3hcrx_seqno_nonloss = seqno;
923 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
928 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
929 > TFRC_RECV_NUM_LATE_LOSS) {
931 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
932 hcrx->ccid3hcrx_ccval_nonloss);
933 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
934 dccp_inc_seqno(&tmp_seqno);
935 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
936 dccp_inc_seqno(&tmp_seqno);
937 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
938 tmp_seqno, &ccval)) {
939 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
940 hcrx->ccid3hcrx_ccval_nonloss = ccval;
941 dccp_inc_seqno(&tmp_seqno);
945 /* FIXME - this code could be simplified with above while */
946 /* but works at moment */
947 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
948 hcrx->ccid3hcrx_seqno_nonloss = seqno;
949 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
953 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
954 &hcrx->ccid3hcrx_li_hist, packet,
955 hcrx->ccid3hcrx_seqno_nonloss);
959 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
961 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
962 const struct dccp_options_received *opt_recv;
963 struct dccp_rx_hist_entry *packet;
965 u32 p_prev, rtt_prev, r_sample, t_elapsed;
968 BUG_ON(hcrx == NULL);
970 opt_recv = &dccp_sk(sk)->dccps_options_received;
972 switch (DCCP_SKB_CB(skb)->dccpd_type) {
974 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
976 case DCCP_PKT_DATAACK:
977 if (opt_recv->dccpor_timestamp_echo == 0)
979 rtt_prev = hcrx->ccid3hcrx_rtt;
980 dccp_timestamp(sk, &now);
981 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
982 r_sample = timeval_usecs(&now);
983 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
985 if (unlikely(r_sample <= t_elapsed))
986 DCCP_WARN("r_sample=%uus, t_elapsed=%uus\n",
987 r_sample, t_elapsed);
989 r_sample -= t_elapsed;
991 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
992 hcrx->ccid3hcrx_rtt = r_sample;
994 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
997 if (rtt_prev != hcrx->ccid3hcrx_rtt)
998 ccid3_pr_debug("%s, New RTT=%uus, elapsed time=%u\n",
999 dccp_role(sk), hcrx->ccid3hcrx_rtt,
1000 opt_recv->dccpor_elapsed_time);
1004 default: /* We're not interested in other packet types, move along */
1008 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
1010 if (unlikely(packet == NULL)) {
1011 DCCP_WARN("%s, sk=%p, Not enough mem to add rx packet "
1012 "to history, consider it lost!\n", dccp_role(sk), sk);
1016 loss = ccid3_hc_rx_detect_loss(sk, packet);
1018 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1021 switch (hcrx->ccid3hcrx_state) {
1022 case TFRC_RSTATE_NO_DATA:
1023 ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial "
1026 dccp_state_name(sk->sk_state), skb);
1027 ccid3_hc_rx_send_feedback(sk);
1028 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1030 case TFRC_RSTATE_DATA:
1031 hcrx->ccid3hcrx_bytes_recv += skb->len -
1032 dccp_hdr(skb)->dccph_doff * 4;
1036 dccp_timestamp(sk, &now);
1037 if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
1038 hcrx->ccid3hcrx_rtt) {
1039 hcrx->ccid3hcrx_tstamp_last_ack = now;
1040 ccid3_hc_rx_send_feedback(sk);
1043 case TFRC_RSTATE_TERM:
1044 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
1048 /* Dealing with packet loss */
1049 ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n",
1050 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1052 p_prev = hcrx->ccid3hcrx_p;
1054 /* Calculate loss event rate */
1055 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1056 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1058 /* Scaling up by 1000000 as fixed decimal */
1060 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1062 DCCP_BUG("empty loss history");
1064 if (hcrx->ccid3hcrx_p > p_prev) {
1065 ccid3_hc_rx_send_feedback(sk);
1070 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1072 struct dccp_sock *dp = dccp_sk(sk);
1073 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1075 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
1077 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
1078 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
1079 hcrx->ccid3hcrx_s = dp->dccps_packet_size;
1081 hcrx->ccid3hcrx_s = TFRC_STD_PACKET_SIZE;
1083 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1084 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1085 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1086 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1087 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1088 hcrx->ccid3hcrx_rtt = 5000; /* XXX 5ms for now... */
1092 static void ccid3_hc_rx_exit(struct sock *sk)
1094 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1096 BUG_ON(hcrx == NULL);
1098 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1100 /* Empty packet history */
1101 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1103 /* Empty loss interval history */
1104 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1107 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1109 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1111 /* Listen socks doesn't have a private CCID block */
1112 if (sk->sk_state == DCCP_LISTEN)
1115 BUG_ON(hcrx == NULL);
1117 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1118 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1119 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1122 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1124 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1126 /* Listen socks doesn't have a private CCID block */
1127 if (sk->sk_state == DCCP_LISTEN)
1130 BUG_ON(hctx == NULL);
1132 info->tcpi_rto = hctx->ccid3hctx_t_rto;
1133 info->tcpi_rtt = hctx->ccid3hctx_rtt;
1136 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1137 u32 __user *optval, int __user *optlen)
1139 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1142 /* Listen socks doesn't have a private CCID block */
1143 if (sk->sk_state == DCCP_LISTEN)
1147 case DCCP_SOCKOPT_CCID_RX_INFO:
1148 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1150 len = sizeof(hcrx->ccid3hcrx_tfrc);
1151 val = &hcrx->ccid3hcrx_tfrc;
1154 return -ENOPROTOOPT;
1157 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1163 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1164 u32 __user *optval, int __user *optlen)
1166 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1169 /* Listen socks doesn't have a private CCID block */
1170 if (sk->sk_state == DCCP_LISTEN)
1174 case DCCP_SOCKOPT_CCID_TX_INFO:
1175 if (len < sizeof(hctx->ccid3hctx_tfrc))
1177 len = sizeof(hctx->ccid3hctx_tfrc);
1178 val = &hctx->ccid3hctx_tfrc;
1181 return -ENOPROTOOPT;
1184 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1190 static struct ccid_operations ccid3 = {
1191 .ccid_id = DCCPC_CCID3,
1192 .ccid_name = "ccid3",
1193 .ccid_owner = THIS_MODULE,
1194 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1195 .ccid_hc_tx_init = ccid3_hc_tx_init,
1196 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1197 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1198 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1199 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1200 .ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
1201 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1202 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1203 .ccid_hc_rx_init = ccid3_hc_rx_init,
1204 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1205 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1206 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1207 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1208 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1209 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1210 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1213 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1214 module_param(ccid3_debug, int, 0444);
1215 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1218 static __init int ccid3_module_init(void)
1222 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1223 if (ccid3_rx_hist == NULL)
1226 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1227 if (ccid3_tx_hist == NULL)
1230 ccid3_li_hist = dccp_li_hist_new("ccid3");
1231 if (ccid3_li_hist == NULL)
1234 rc = ccid_register(&ccid3);
1236 goto out_free_loss_interval_history;
1240 out_free_loss_interval_history:
1241 dccp_li_hist_delete(ccid3_li_hist);
1242 ccid3_li_hist = NULL;
1244 dccp_tx_hist_delete(ccid3_tx_hist);
1245 ccid3_tx_hist = NULL;
1247 dccp_rx_hist_delete(ccid3_rx_hist);
1248 ccid3_rx_hist = NULL;
1251 module_init(ccid3_module_init);
1253 static __exit void ccid3_module_exit(void)
1255 ccid_unregister(&ccid3);
1257 if (ccid3_tx_hist != NULL) {
1258 dccp_tx_hist_delete(ccid3_tx_hist);
1259 ccid3_tx_hist = NULL;
1261 if (ccid3_rx_hist != NULL) {
1262 dccp_rx_hist_delete(ccid3_rx_hist);
1263 ccid3_rx_hist = NULL;
1265 if (ccid3_li_hist != NULL) {
1266 dccp_li_hist_delete(ccid3_li_hist);
1267 ccid3_li_hist = NULL;
1270 module_exit(ccid3_module_exit);
1272 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1273 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1274 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1275 MODULE_LICENSE("GPL");
1276 MODULE_ALIAS("net-dccp-ccid-3");