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);
389 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
391 const struct dccp_sock *dp = dccp_sk(sk);
392 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
393 struct ccid3_options_received *opt_recv;
394 struct dccp_tx_hist_entry *packet;
396 unsigned long next_tmout;
402 BUG_ON(hctx == NULL);
404 /* we are only interested in ACKs */
405 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
406 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
409 opt_recv = &hctx->ccid3hctx_options_received;
411 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
412 x_recv = opt_recv->ccid3or_receive_rate;
413 pinv = opt_recv->ccid3or_loss_event_rate;
415 switch (hctx->ccid3hctx_state) {
416 case TFRC_SSTATE_NO_SENT:
417 /* FIXME: what to do here? */
419 case TFRC_SSTATE_NO_FBACK:
420 case TFRC_SSTATE_FBACK:
421 /* Calculate new round trip sample by
422 * R_sample = (now - t_recvdata) - t_delay */
423 /* get t_recvdata from history */
424 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
425 DCCP_SKB_CB(skb)->dccpd_ack_seq);
426 if (unlikely(packet == NULL)) {
427 DCCP_WARN("%s, sk=%p, seqno %llu(%s) does't exist "
428 "in history!\n", dccp_role(sk), sk,
429 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
430 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
435 dccp_timestamp(sk, &now);
436 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
437 if (unlikely(r_sample <= t_elapsed))
438 DCCP_WARN("r_sample=%uus,t_elapsed=%uus\n",
439 r_sample, t_elapsed);
441 r_sample -= t_elapsed;
443 /* Update RTT estimate by
444 * If (No feedback recv)
447 * R = q * R + (1 - q) * R_sample;
449 * q is a constant, RFC 3448 recomments 0.9
451 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
452 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
453 hctx->ccid3hctx_rtt = r_sample;
455 hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
458 ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
459 "r_sample=%us\n", dccp_role(sk), sk,
460 hctx->ccid3hctx_rtt, r_sample);
462 /* Update timeout interval */
463 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
466 /* Update receive rate */
467 hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
469 /* Update loss event rate */
470 if (pinv == ~0 || pinv == 0)
471 hctx->ccid3hctx_p = 0;
473 hctx->ccid3hctx_p = 1000000 / pinv;
475 if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
476 hctx->ccid3hctx_p = TFRC_SMALLEST_P;
477 ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
482 /* unschedule no feedback timer */
483 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
485 /* Update sending rate */
486 ccid3_hc_tx_update_x(sk);
488 /* Update next send time */
489 timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
490 hctx->ccid3hctx_t_ipi);
491 ccid3_calc_new_t_ipi(hctx);
492 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
493 hctx->ccid3hctx_t_ipi);
494 ccid3_calc_new_delta(hctx);
496 /* remove all packets older than the one acked from history */
497 dccp_tx_hist_purge_older(ccid3_tx_hist,
498 &hctx->ccid3hctx_hist, packet);
500 * As we have calculated new ipi, delta, t_nom it is possible that
501 * we now can send a packet, so wake up dccp_wait_for_ccids.
503 sk->sk_write_space(sk);
506 * Schedule no feedback timer to expire in
507 * max(4 * R, 2 * s / X)
509 next_tmout = max(hctx->ccid3hctx_t_rto,
510 2 * usecs_div(hctx->ccid3hctx_s,
513 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
514 "expire in %lu jiffies (%luus)\n",
516 usecs_to_jiffies(next_tmout), next_tmout);
518 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
519 jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
522 hctx->ccid3hctx_idle = 1;
524 case TFRC_SSTATE_TERM:
525 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
530 static int ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
532 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
534 BUG_ON(hctx == NULL);
536 if (sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)
537 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
541 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
542 unsigned char len, u16 idx,
543 unsigned char *value)
546 const struct dccp_sock *dp = dccp_sk(sk);
547 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
548 struct ccid3_options_received *opt_recv;
550 BUG_ON(hctx == NULL);
552 opt_recv = &hctx->ccid3hctx_options_received;
554 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
555 opt_recv->ccid3or_seqno = dp->dccps_gsr;
556 opt_recv->ccid3or_loss_event_rate = ~0;
557 opt_recv->ccid3or_loss_intervals_idx = 0;
558 opt_recv->ccid3or_loss_intervals_len = 0;
559 opt_recv->ccid3or_receive_rate = 0;
563 case TFRC_OPT_LOSS_EVENT_RATE:
564 if (unlikely(len != 4)) {
565 DCCP_WARN("%s, sk=%p, invalid len %d "
566 "for TFRC_OPT_LOSS_EVENT_RATE\n",
567 dccp_role(sk), sk, len);
570 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
571 ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
573 opt_recv->ccid3or_loss_event_rate);
576 case TFRC_OPT_LOSS_INTERVALS:
577 opt_recv->ccid3or_loss_intervals_idx = idx;
578 opt_recv->ccid3or_loss_intervals_len = len;
579 ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
581 opt_recv->ccid3or_loss_intervals_idx,
582 opt_recv->ccid3or_loss_intervals_len);
584 case TFRC_OPT_RECEIVE_RATE:
585 if (unlikely(len != 4)) {
586 DCCP_WARN("%s, sk=%p, invalid len %d "
587 "for TFRC_OPT_RECEIVE_RATE\n",
588 dccp_role(sk), sk, len);
591 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
592 ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
594 opt_recv->ccid3or_receive_rate);
602 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
604 struct dccp_sock *dp = dccp_sk(sk);
605 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
607 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
608 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
609 hctx->ccid3hctx_s = dp->dccps_packet_size;
611 hctx->ccid3hctx_s = TFRC_STD_PACKET_SIZE;
613 /* Set transmission rate to 1 packet per second */
614 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
615 hctx->ccid3hctx_t_rto = USEC_PER_SEC;
616 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
617 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
619 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
620 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
621 init_timer(&hctx->ccid3hctx_no_feedback_timer);
626 static void ccid3_hc_tx_exit(struct sock *sk)
628 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
630 BUG_ON(hctx == NULL);
632 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
633 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
635 /* Empty packet history */
636 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
640 * RX Half Connection methods
643 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
644 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
646 static char *ccid3_rx_state_names[] = {
647 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
648 [TFRC_RSTATE_DATA] = "DATA",
649 [TFRC_RSTATE_TERM] = "TERM",
652 return ccid3_rx_state_names[state];
656 static void ccid3_hc_rx_set_state(struct sock *sk,
657 enum ccid3_hc_rx_states state)
659 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
660 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
662 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
663 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
664 ccid3_rx_state_name(state));
665 WARN_ON(state == oldstate);
666 hcrx->ccid3hcrx_state = state;
669 static void ccid3_hc_rx_send_feedback(struct sock *sk)
671 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
672 struct dccp_sock *dp = dccp_sk(sk);
673 struct dccp_rx_hist_entry *packet;
676 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
678 dccp_timestamp(sk, &now);
680 switch (hcrx->ccid3hcrx_state) {
681 case TFRC_RSTATE_NO_DATA:
682 hcrx->ccid3hcrx_x_recv = 0;
684 case TFRC_RSTATE_DATA: {
685 const u32 delta = timeval_delta(&now,
686 &hcrx->ccid3hcrx_tstamp_last_feedback);
687 hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
691 case TFRC_RSTATE_TERM:
692 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
696 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
697 if (unlikely(packet == NULL)) {
698 DCCP_WARN("%s, sk=%p, no data packet in history!\n",
703 hcrx->ccid3hcrx_tstamp_last_feedback = now;
704 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
705 hcrx->ccid3hcrx_bytes_recv = 0;
707 /* Convert to multiples of 10us */
708 hcrx->ccid3hcrx_elapsed_time =
709 timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
710 if (hcrx->ccid3hcrx_p == 0)
711 hcrx->ccid3hcrx_pinv = ~0;
713 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
714 dp->dccps_hc_rx_insert_options = 1;
718 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
720 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
723 BUG_ON(hcrx == NULL);
725 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
728 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
730 if (dccp_packet_without_ack(skb))
733 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
734 pinv = htonl(hcrx->ccid3hcrx_pinv);
736 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
737 dccp_insert_option_elapsed_time(sk, skb,
738 hcrx->ccid3hcrx_elapsed_time)) ||
739 dccp_insert_option_timestamp(sk, skb) ||
740 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
741 &pinv, sizeof(pinv)) ||
742 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
743 &x_recv, sizeof(x_recv)))
749 /* calculate first loss interval
751 * returns estimated loss interval in usecs */
753 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
755 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
756 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
757 u32 rtt, delta, x_recv, fval, p, tmp2;
758 struct timeval tstamp = { 0, };
764 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
766 if (dccp_rx_hist_entry_data_packet(entry)) {
771 tstamp = entry->dccphrx_tstamp;
772 win_count = entry->dccphrx_ccval;
776 interval = win_count - entry->dccphrx_ccval;
778 interval += TFRC_WIN_COUNT_LIMIT;
786 if (unlikely(step == 0)) {
787 DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
792 if (unlikely(interval == 0)) {
793 DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
794 "Defaulting to 1\n", dccp_role(sk), sk);
799 DCCP_CRIT("tail is null\n");
802 rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
803 ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
804 dccp_role(sk), sk, rtt);
807 DCCP_WARN("RTT==0, setting to 1\n");
811 dccp_timestamp(sk, &tstamp);
812 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
813 x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);
816 x_recv = hcrx->ccid3hcrx_x_recv;
818 tmp1 = (u64)x_recv * (u64)rtt;
819 do_div(tmp1,10000000);
823 DCCP_CRIT("tmp2 = 0, x_recv = %u, rtt =%u\n", x_recv, rtt);
827 fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
828 /* do not alter order above or you will get overflow on 32 bit */
829 p = tfrc_calc_x_reverse_lookup(fval);
830 ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
831 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
839 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
841 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
842 struct dccp_li_hist_entry *head;
845 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
846 if (!dccp_li_hist_interval_new(ccid3_li_hist,
847 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
850 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
851 struct dccp_li_hist_entry, dccplih_node);
852 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
854 struct dccp_li_hist_entry *entry;
855 struct list_head *tail;
857 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
858 struct dccp_li_hist_entry, dccplih_node);
859 /* FIXME win count check removed as was wrong */
860 /* should make this check with receive history */
861 /* and compare there as per section 10.2 of RFC4342 */
863 /* new loss event detected */
864 /* calculate last interval length */
865 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
866 entry = dccp_li_hist_entry_new(ccid3_li_hist, SLAB_ATOMIC);
869 DCCP_BUG("out of memory - can not allocate entry");
873 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
875 tail = hcrx->ccid3hcrx_li_hist.prev;
877 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
879 /* Create the newest interval */
880 entry->dccplih_seqno = seq_loss;
881 entry->dccplih_interval = seq_temp;
882 entry->dccplih_win_count = win_loss;
886 static int ccid3_hc_rx_detect_loss(struct sock *sk,
887 struct dccp_rx_hist_entry *packet)
889 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
890 struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
891 u64 seqno = packet->dccphrx_seqno;
897 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
900 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
901 hcrx->ccid3hcrx_seqno_nonloss = seqno;
902 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
907 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
908 > TFRC_RECV_NUM_LATE_LOSS) {
910 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
911 hcrx->ccid3hcrx_ccval_nonloss);
912 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
913 dccp_inc_seqno(&tmp_seqno);
914 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
915 dccp_inc_seqno(&tmp_seqno);
916 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
917 tmp_seqno, &ccval)) {
918 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
919 hcrx->ccid3hcrx_ccval_nonloss = ccval;
920 dccp_inc_seqno(&tmp_seqno);
924 /* FIXME - this code could be simplified with above while */
925 /* but works at moment */
926 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
927 hcrx->ccid3hcrx_seqno_nonloss = seqno;
928 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
932 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
933 &hcrx->ccid3hcrx_li_hist, packet,
934 hcrx->ccid3hcrx_seqno_nonloss);
938 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
940 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
941 const struct dccp_options_received *opt_recv;
942 struct dccp_rx_hist_entry *packet;
944 u32 p_prev, rtt_prev, r_sample, t_elapsed;
947 BUG_ON(hcrx == NULL);
949 opt_recv = &dccp_sk(sk)->dccps_options_received;
951 switch (DCCP_SKB_CB(skb)->dccpd_type) {
953 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
955 case DCCP_PKT_DATAACK:
956 if (opt_recv->dccpor_timestamp_echo == 0)
958 rtt_prev = hcrx->ccid3hcrx_rtt;
959 dccp_timestamp(sk, &now);
960 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
961 r_sample = timeval_usecs(&now);
962 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
964 if (unlikely(r_sample <= t_elapsed))
965 DCCP_WARN("r_sample=%uus, t_elapsed=%uus\n",
966 r_sample, t_elapsed);
968 r_sample -= t_elapsed;
970 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
971 hcrx->ccid3hcrx_rtt = r_sample;
973 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
976 if (rtt_prev != hcrx->ccid3hcrx_rtt)
977 ccid3_pr_debug("%s, New RTT=%uus, elapsed time=%u\n",
978 dccp_role(sk), hcrx->ccid3hcrx_rtt,
979 opt_recv->dccpor_elapsed_time);
983 default: /* We're not interested in other packet types, move along */
987 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
989 if (unlikely(packet == NULL)) {
990 DCCP_WARN("%s, sk=%p, Not enough mem to add rx packet "
991 "to history, consider it lost!\n", dccp_role(sk), sk);
995 loss = ccid3_hc_rx_detect_loss(sk, packet);
997 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1000 switch (hcrx->ccid3hcrx_state) {
1001 case TFRC_RSTATE_NO_DATA:
1002 ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial "
1005 dccp_state_name(sk->sk_state), skb);
1006 ccid3_hc_rx_send_feedback(sk);
1007 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1009 case TFRC_RSTATE_DATA:
1010 hcrx->ccid3hcrx_bytes_recv += skb->len -
1011 dccp_hdr(skb)->dccph_doff * 4;
1015 dccp_timestamp(sk, &now);
1016 if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
1017 hcrx->ccid3hcrx_rtt) {
1018 hcrx->ccid3hcrx_tstamp_last_ack = now;
1019 ccid3_hc_rx_send_feedback(sk);
1022 case TFRC_RSTATE_TERM:
1023 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
1027 /* Dealing with packet loss */
1028 ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n",
1029 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1031 p_prev = hcrx->ccid3hcrx_p;
1033 /* Calculate loss event rate */
1034 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1035 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1037 /* Scaling up by 1000000 as fixed decimal */
1039 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1041 DCCP_BUG("empty loss history");
1043 if (hcrx->ccid3hcrx_p > p_prev) {
1044 ccid3_hc_rx_send_feedback(sk);
1049 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1051 struct dccp_sock *dp = dccp_sk(sk);
1052 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1054 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
1056 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
1057 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
1058 hcrx->ccid3hcrx_s = dp->dccps_packet_size;
1060 hcrx->ccid3hcrx_s = TFRC_STD_PACKET_SIZE;
1062 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1063 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1064 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1065 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1066 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1067 hcrx->ccid3hcrx_rtt = 5000; /* XXX 5ms for now... */
1071 static void ccid3_hc_rx_exit(struct sock *sk)
1073 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1075 BUG_ON(hcrx == NULL);
1077 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1079 /* Empty packet history */
1080 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1082 /* Empty loss interval history */
1083 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1086 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1088 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1090 /* Listen socks doesn't have a private CCID block */
1091 if (sk->sk_state == DCCP_LISTEN)
1094 BUG_ON(hcrx == NULL);
1096 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1097 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1098 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1101 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1103 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1105 /* Listen socks doesn't have a private CCID block */
1106 if (sk->sk_state == DCCP_LISTEN)
1109 BUG_ON(hctx == NULL);
1111 info->tcpi_rto = hctx->ccid3hctx_t_rto;
1112 info->tcpi_rtt = hctx->ccid3hctx_rtt;
1115 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1116 u32 __user *optval, int __user *optlen)
1118 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1121 /* Listen socks doesn't have a private CCID block */
1122 if (sk->sk_state == DCCP_LISTEN)
1126 case DCCP_SOCKOPT_CCID_RX_INFO:
1127 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1129 len = sizeof(hcrx->ccid3hcrx_tfrc);
1130 val = &hcrx->ccid3hcrx_tfrc;
1133 return -ENOPROTOOPT;
1136 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1142 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1143 u32 __user *optval, int __user *optlen)
1145 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1148 /* Listen socks doesn't have a private CCID block */
1149 if (sk->sk_state == DCCP_LISTEN)
1153 case DCCP_SOCKOPT_CCID_TX_INFO:
1154 if (len < sizeof(hctx->ccid3hctx_tfrc))
1156 len = sizeof(hctx->ccid3hctx_tfrc);
1157 val = &hctx->ccid3hctx_tfrc;
1160 return -ENOPROTOOPT;
1163 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1169 static struct ccid_operations ccid3 = {
1170 .ccid_id = DCCPC_CCID3,
1171 .ccid_name = "ccid3",
1172 .ccid_owner = THIS_MODULE,
1173 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1174 .ccid_hc_tx_init = ccid3_hc_tx_init,
1175 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1176 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1177 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1178 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1179 .ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
1180 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1181 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1182 .ccid_hc_rx_init = ccid3_hc_rx_init,
1183 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1184 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1185 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1186 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1187 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1188 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1189 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1192 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1193 module_param(ccid3_debug, int, 0444);
1194 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1197 static __init int ccid3_module_init(void)
1201 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1202 if (ccid3_rx_hist == NULL)
1205 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1206 if (ccid3_tx_hist == NULL)
1209 ccid3_li_hist = dccp_li_hist_new("ccid3");
1210 if (ccid3_li_hist == NULL)
1213 rc = ccid_register(&ccid3);
1215 goto out_free_loss_interval_history;
1219 out_free_loss_interval_history:
1220 dccp_li_hist_delete(ccid3_li_hist);
1221 ccid3_li_hist = NULL;
1223 dccp_tx_hist_delete(ccid3_tx_hist);
1224 ccid3_tx_hist = NULL;
1226 dccp_rx_hist_delete(ccid3_rx_hist);
1227 ccid3_rx_hist = NULL;
1230 module_init(ccid3_module_init);
1232 static __exit void ccid3_module_exit(void)
1234 ccid_unregister(&ccid3);
1236 if (ccid3_tx_hist != NULL) {
1237 dccp_tx_hist_delete(ccid3_tx_hist);
1238 ccid3_tx_hist = NULL;
1240 if (ccid3_rx_hist != NULL) {
1241 dccp_rx_hist_delete(ccid3_rx_hist);
1242 ccid3_rx_hist = NULL;
1244 if (ccid3_li_hist != NULL) {
1245 dccp_li_hist_delete(ccid3_li_hist);
1246 ccid3_li_hist = NULL;
1249 module_exit(ccid3_module_exit);
1251 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1252 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1253 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1254 MODULE_LICENSE("GPL");
1255 MODULE_ALIAS("net-dccp-ccid-3");