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;
250 static int ccid3_hc_tx_send_packet(struct sock *sk,
251 struct sk_buff *skb, int len)
253 struct dccp_sock *dp = dccp_sk(sk);
254 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
255 struct dccp_tx_hist_entry *new_packet;
260 BUG_ON(hctx == NULL);
262 /* Check if pure ACK or Terminating*/
264 * XXX: We only call this function for DATA and DATAACK, on, these
265 * packets can have zero length, but why the comment about "pure ACK"?
267 if (unlikely(len == 0))
270 /* See if last packet allocated was not sent */
271 new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
272 if (new_packet == NULL || new_packet->dccphtx_sent) {
273 new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
277 if (unlikely(new_packet == NULL)) {
278 DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
279 "send refused\n", dccp_role(sk), sk);
283 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
286 dccp_timestamp(sk, &now);
288 switch (hctx->ccid3hctx_state) {
289 case TFRC_SSTATE_NO_SENT:
290 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
291 jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
292 hctx->ccid3hctx_last_win_count = 0;
293 hctx->ccid3hctx_t_last_win_count = now;
294 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
296 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
297 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
298 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
299 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
301 /* Set t_0 for initial packet */
302 hctx->ccid3hctx_t_nom = now;
305 case TFRC_SSTATE_NO_FBACK:
306 case TFRC_SSTATE_FBACK:
307 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
309 * Scheduling of packet transmissions [RFC 3448, 4.6]
311 * if (t_now > t_nom - delta)
312 * // send the packet now
314 * // send the packet in (t_nom - t_now) milliseconds.
316 if (delay < hctx->ccid3hctx_delta)
321 case TFRC_SSTATE_TERM:
322 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
327 /* Can we send? if so add options and add to packet history */
329 dp->dccps_hc_tx_insert_options = 1;
330 new_packet->dccphtx_ccval =
331 DCCP_SKB_CB(skb)->dccpd_ccval =
332 hctx->ccid3hctx_last_win_count;
333 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
334 hctx->ccid3hctx_t_ipi);
340 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
342 const struct dccp_sock *dp = dccp_sk(sk);
343 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
346 BUG_ON(hctx == NULL);
348 dccp_timestamp(sk, &now);
350 /* check if we have sent a data packet */
352 unsigned long quarter_rtt;
353 struct dccp_tx_hist_entry *packet;
355 packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
356 if (unlikely(packet == NULL)) {
357 DCCP_WARN("packet doesn't exist in history!\n");
360 if (unlikely(packet->dccphtx_sent)) {
361 DCCP_WARN("no unsent packet in history!\n");
364 packet->dccphtx_tstamp = now;
365 packet->dccphtx_seqno = dp->dccps_gss;
367 * Check if win_count have changed
368 * Algorithm in "8.1. Window Counter Value" in RFC 4342.
370 quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
371 if (likely(hctx->ccid3hctx_rtt > 8))
372 quarter_rtt /= hctx->ccid3hctx_rtt / 4;
374 if (quarter_rtt > 0) {
375 hctx->ccid3hctx_t_last_win_count = now;
376 hctx->ccid3hctx_last_win_count = (hctx->ccid3hctx_last_win_count +
377 min_t(unsigned long, quarter_rtt, 5)) % 16;
378 ccid3_pr_debug("%s, sk=%p, window changed from "
381 packet->dccphtx_ccval,
382 hctx->ccid3hctx_last_win_count);
385 hctx->ccid3hctx_idle = 0;
386 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
387 packet->dccphtx_sent = 1;
389 ccid3_pr_debug("%s, sk=%p, seqno=%llu NOT inserted!\n",
390 dccp_role(sk), sk, dp->dccps_gss);
392 switch (hctx->ccid3hctx_state) {
393 case TFRC_SSTATE_NO_SENT:
394 /* if first wasn't pure ack */
396 DCCP_CRIT("%s, First packet sent is noted "
397 "as a data packet", dccp_role(sk));
399 case TFRC_SSTATE_NO_FBACK:
400 /* t_nom, t_ipi, delta do not change until feedback arrives */
402 case TFRC_SSTATE_FBACK:
404 timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
405 hctx->ccid3hctx_t_ipi);
406 ccid3_calc_new_t_ipi(hctx);
407 ccid3_calc_new_delta(hctx);
408 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
409 hctx->ccid3hctx_t_ipi);
412 case TFRC_SSTATE_TERM:
413 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
418 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
420 const struct dccp_sock *dp = dccp_sk(sk);
421 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
422 struct ccid3_options_received *opt_recv;
423 struct dccp_tx_hist_entry *packet;
425 unsigned long next_tmout;
431 BUG_ON(hctx == NULL);
433 /* we are only interested in ACKs */
434 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
435 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
438 opt_recv = &hctx->ccid3hctx_options_received;
440 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
441 x_recv = opt_recv->ccid3or_receive_rate;
442 pinv = opt_recv->ccid3or_loss_event_rate;
444 switch (hctx->ccid3hctx_state) {
445 case TFRC_SSTATE_NO_SENT:
446 /* FIXME: what to do here? */
448 case TFRC_SSTATE_NO_FBACK:
449 case TFRC_SSTATE_FBACK:
450 /* Calculate new round trip sample by
451 * R_sample = (now - t_recvdata) - t_delay */
452 /* get t_recvdata from history */
453 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
454 DCCP_SKB_CB(skb)->dccpd_ack_seq);
455 if (unlikely(packet == NULL)) {
456 DCCP_WARN("%s, sk=%p, seqno %llu(%s) does't exist "
457 "in history!\n", dccp_role(sk), sk,
458 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
459 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
464 dccp_timestamp(sk, &now);
465 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
466 if (unlikely(r_sample <= t_elapsed))
467 DCCP_WARN("r_sample=%uus,t_elapsed=%uus\n",
468 r_sample, t_elapsed);
470 r_sample -= t_elapsed;
472 /* Update RTT estimate by
473 * If (No feedback recv)
476 * R = q * R + (1 - q) * R_sample;
478 * q is a constant, RFC 3448 recomments 0.9
480 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
481 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
482 hctx->ccid3hctx_rtt = r_sample;
484 hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
487 ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
488 "r_sample=%us\n", dccp_role(sk), sk,
489 hctx->ccid3hctx_rtt, r_sample);
491 /* Update timeout interval */
492 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
495 /* Update receive rate */
496 hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
498 /* Update loss event rate */
499 if (pinv == ~0 || pinv == 0)
500 hctx->ccid3hctx_p = 0;
502 hctx->ccid3hctx_p = 1000000 / pinv;
504 if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
505 hctx->ccid3hctx_p = TFRC_SMALLEST_P;
506 ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
511 /* unschedule no feedback timer */
512 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
514 /* Update sending rate */
515 ccid3_hc_tx_update_x(sk);
517 /* Update next send time */
518 timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
519 hctx->ccid3hctx_t_ipi);
520 ccid3_calc_new_t_ipi(hctx);
521 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
522 hctx->ccid3hctx_t_ipi);
523 ccid3_calc_new_delta(hctx);
525 /* remove all packets older than the one acked from history */
526 dccp_tx_hist_purge_older(ccid3_tx_hist,
527 &hctx->ccid3hctx_hist, packet);
529 * As we have calculated new ipi, delta, t_nom it is possible that
530 * we now can send a packet, so wake up dccp_wait_for_ccids.
532 sk->sk_write_space(sk);
535 * Schedule no feedback timer to expire in
536 * max(4 * R, 2 * s / X)
538 next_tmout = max(hctx->ccid3hctx_t_rto,
539 2 * usecs_div(hctx->ccid3hctx_s,
542 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
543 "expire in %lu jiffies (%luus)\n",
545 usecs_to_jiffies(next_tmout), next_tmout);
547 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
548 jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
551 hctx->ccid3hctx_idle = 1;
553 case TFRC_SSTATE_TERM:
554 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
559 static int ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
561 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
563 BUG_ON(hctx == NULL);
565 if (sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)
566 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
570 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
571 unsigned char len, u16 idx,
572 unsigned char *value)
575 const struct dccp_sock *dp = dccp_sk(sk);
576 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
577 struct ccid3_options_received *opt_recv;
579 BUG_ON(hctx == NULL);
581 opt_recv = &hctx->ccid3hctx_options_received;
583 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
584 opt_recv->ccid3or_seqno = dp->dccps_gsr;
585 opt_recv->ccid3or_loss_event_rate = ~0;
586 opt_recv->ccid3or_loss_intervals_idx = 0;
587 opt_recv->ccid3or_loss_intervals_len = 0;
588 opt_recv->ccid3or_receive_rate = 0;
592 case TFRC_OPT_LOSS_EVENT_RATE:
593 if (unlikely(len != 4)) {
594 DCCP_WARN("%s, sk=%p, invalid len %d "
595 "for TFRC_OPT_LOSS_EVENT_RATE\n",
596 dccp_role(sk), sk, len);
599 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
600 ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
602 opt_recv->ccid3or_loss_event_rate);
605 case TFRC_OPT_LOSS_INTERVALS:
606 opt_recv->ccid3or_loss_intervals_idx = idx;
607 opt_recv->ccid3or_loss_intervals_len = len;
608 ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
610 opt_recv->ccid3or_loss_intervals_idx,
611 opt_recv->ccid3or_loss_intervals_len);
613 case TFRC_OPT_RECEIVE_RATE:
614 if (unlikely(len != 4)) {
615 DCCP_WARN("%s, sk=%p, invalid len %d "
616 "for TFRC_OPT_RECEIVE_RATE\n",
617 dccp_role(sk), sk, len);
620 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
621 ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
623 opt_recv->ccid3or_receive_rate);
631 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
633 struct dccp_sock *dp = dccp_sk(sk);
634 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
636 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
637 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
638 hctx->ccid3hctx_s = dp->dccps_packet_size;
640 hctx->ccid3hctx_s = TFRC_STD_PACKET_SIZE;
642 /* Set transmission rate to 1 packet per second */
643 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
644 hctx->ccid3hctx_t_rto = USEC_PER_SEC;
645 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
646 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
648 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
649 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
650 init_timer(&hctx->ccid3hctx_no_feedback_timer);
655 static void ccid3_hc_tx_exit(struct sock *sk)
657 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
659 BUG_ON(hctx == NULL);
661 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
662 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
664 /* Empty packet history */
665 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
669 * RX Half Connection methods
672 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
673 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
675 static char *ccid3_rx_state_names[] = {
676 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
677 [TFRC_RSTATE_DATA] = "DATA",
678 [TFRC_RSTATE_TERM] = "TERM",
681 return ccid3_rx_state_names[state];
685 static void ccid3_hc_rx_set_state(struct sock *sk,
686 enum ccid3_hc_rx_states state)
688 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
689 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
691 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
692 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
693 ccid3_rx_state_name(state));
694 WARN_ON(state == oldstate);
695 hcrx->ccid3hcrx_state = state;
698 static void ccid3_hc_rx_send_feedback(struct sock *sk)
700 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
701 struct dccp_sock *dp = dccp_sk(sk);
702 struct dccp_rx_hist_entry *packet;
705 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
707 dccp_timestamp(sk, &now);
709 switch (hcrx->ccid3hcrx_state) {
710 case TFRC_RSTATE_NO_DATA:
711 hcrx->ccid3hcrx_x_recv = 0;
713 case TFRC_RSTATE_DATA: {
714 const u32 delta = timeval_delta(&now,
715 &hcrx->ccid3hcrx_tstamp_last_feedback);
716 hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
720 case TFRC_RSTATE_TERM:
721 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
725 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
726 if (unlikely(packet == NULL)) {
727 DCCP_WARN("%s, sk=%p, no data packet in history!\n",
732 hcrx->ccid3hcrx_tstamp_last_feedback = now;
733 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
734 hcrx->ccid3hcrx_bytes_recv = 0;
736 /* Convert to multiples of 10us */
737 hcrx->ccid3hcrx_elapsed_time =
738 timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
739 if (hcrx->ccid3hcrx_p == 0)
740 hcrx->ccid3hcrx_pinv = ~0;
742 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
743 dp->dccps_hc_rx_insert_options = 1;
747 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
749 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
752 BUG_ON(hcrx == NULL);
754 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
757 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
759 if (dccp_packet_without_ack(skb))
762 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
763 pinv = htonl(hcrx->ccid3hcrx_pinv);
765 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
766 dccp_insert_option_elapsed_time(sk, skb,
767 hcrx->ccid3hcrx_elapsed_time)) ||
768 dccp_insert_option_timestamp(sk, skb) ||
769 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
770 &pinv, sizeof(pinv)) ||
771 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
772 &x_recv, sizeof(x_recv)))
778 /* calculate first loss interval
780 * returns estimated loss interval in usecs */
782 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
784 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
785 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
786 u32 rtt, delta, x_recv, fval, p, tmp2;
787 struct timeval tstamp = { 0, };
793 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
795 if (dccp_rx_hist_entry_data_packet(entry)) {
800 tstamp = entry->dccphrx_tstamp;
801 win_count = entry->dccphrx_ccval;
805 interval = win_count - entry->dccphrx_ccval;
807 interval += TFRC_WIN_COUNT_LIMIT;
815 if (unlikely(step == 0)) {
816 DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
821 if (unlikely(interval == 0)) {
822 DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
823 "Defaulting to 1\n", dccp_role(sk), sk);
828 DCCP_CRIT("tail is null\n");
831 rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
832 ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
833 dccp_role(sk), sk, rtt);
836 DCCP_WARN("RTT==0, setting to 1\n");
840 dccp_timestamp(sk, &tstamp);
841 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
842 x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);
845 x_recv = hcrx->ccid3hcrx_x_recv;
847 tmp1 = (u64)x_recv * (u64)rtt;
848 do_div(tmp1,10000000);
852 DCCP_CRIT("tmp2 = 0, x_recv = %u, rtt =%u\n", x_recv, rtt);
856 fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
857 /* do not alter order above or you will get overflow on 32 bit */
858 p = tfrc_calc_x_reverse_lookup(fval);
859 ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
860 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
868 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
870 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
871 struct dccp_li_hist_entry *head;
874 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
875 if (!dccp_li_hist_interval_new(ccid3_li_hist,
876 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
879 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
880 struct dccp_li_hist_entry, dccplih_node);
881 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
883 struct dccp_li_hist_entry *entry;
884 struct list_head *tail;
886 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
887 struct dccp_li_hist_entry, dccplih_node);
888 /* FIXME win count check removed as was wrong */
889 /* should make this check with receive history */
890 /* and compare there as per section 10.2 of RFC4342 */
892 /* new loss event detected */
893 /* calculate last interval length */
894 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
895 entry = dccp_li_hist_entry_new(ccid3_li_hist, SLAB_ATOMIC);
898 DCCP_BUG("out of memory - can not allocate entry");
902 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
904 tail = hcrx->ccid3hcrx_li_hist.prev;
906 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
908 /* Create the newest interval */
909 entry->dccplih_seqno = seq_loss;
910 entry->dccplih_interval = seq_temp;
911 entry->dccplih_win_count = win_loss;
915 static int ccid3_hc_rx_detect_loss(struct sock *sk,
916 struct dccp_rx_hist_entry *packet)
918 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
919 struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
920 u64 seqno = packet->dccphrx_seqno;
926 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
929 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
930 hcrx->ccid3hcrx_seqno_nonloss = seqno;
931 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
936 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
937 > TFRC_RECV_NUM_LATE_LOSS) {
939 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
940 hcrx->ccid3hcrx_ccval_nonloss);
941 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
942 dccp_inc_seqno(&tmp_seqno);
943 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
944 dccp_inc_seqno(&tmp_seqno);
945 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
946 tmp_seqno, &ccval)) {
947 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
948 hcrx->ccid3hcrx_ccval_nonloss = ccval;
949 dccp_inc_seqno(&tmp_seqno);
953 /* FIXME - this code could be simplified with above while */
954 /* but works at moment */
955 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
956 hcrx->ccid3hcrx_seqno_nonloss = seqno;
957 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
961 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
962 &hcrx->ccid3hcrx_li_hist, packet,
963 hcrx->ccid3hcrx_seqno_nonloss);
967 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
969 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
970 const struct dccp_options_received *opt_recv;
971 struct dccp_rx_hist_entry *packet;
973 u32 p_prev, rtt_prev, r_sample, t_elapsed;
976 BUG_ON(hcrx == NULL);
978 opt_recv = &dccp_sk(sk)->dccps_options_received;
980 switch (DCCP_SKB_CB(skb)->dccpd_type) {
982 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
984 case DCCP_PKT_DATAACK:
985 if (opt_recv->dccpor_timestamp_echo == 0)
987 rtt_prev = hcrx->ccid3hcrx_rtt;
988 dccp_timestamp(sk, &now);
989 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
990 r_sample = timeval_usecs(&now);
991 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
993 if (unlikely(r_sample <= t_elapsed))
994 DCCP_WARN("r_sample=%uus, t_elapsed=%uus\n",
995 r_sample, t_elapsed);
997 r_sample -= t_elapsed;
999 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1000 hcrx->ccid3hcrx_rtt = r_sample;
1002 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
1005 if (rtt_prev != hcrx->ccid3hcrx_rtt)
1006 ccid3_pr_debug("%s, New RTT=%uus, elapsed time=%u\n",
1007 dccp_role(sk), hcrx->ccid3hcrx_rtt,
1008 opt_recv->dccpor_elapsed_time);
1012 default: /* We're not interested in other packet types, move along */
1016 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
1018 if (unlikely(packet == NULL)) {
1019 DCCP_WARN("%s, sk=%p, Not enough mem to add rx packet "
1020 "to history, consider it lost!\n", dccp_role(sk), sk);
1024 loss = ccid3_hc_rx_detect_loss(sk, packet);
1026 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1029 switch (hcrx->ccid3hcrx_state) {
1030 case TFRC_RSTATE_NO_DATA:
1031 ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial "
1034 dccp_state_name(sk->sk_state), skb);
1035 ccid3_hc_rx_send_feedback(sk);
1036 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1038 case TFRC_RSTATE_DATA:
1039 hcrx->ccid3hcrx_bytes_recv += skb->len -
1040 dccp_hdr(skb)->dccph_doff * 4;
1044 dccp_timestamp(sk, &now);
1045 if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
1046 hcrx->ccid3hcrx_rtt) {
1047 hcrx->ccid3hcrx_tstamp_last_ack = now;
1048 ccid3_hc_rx_send_feedback(sk);
1051 case TFRC_RSTATE_TERM:
1052 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
1056 /* Dealing with packet loss */
1057 ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n",
1058 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1060 p_prev = hcrx->ccid3hcrx_p;
1062 /* Calculate loss event rate */
1063 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1064 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1066 /* Scaling up by 1000000 as fixed decimal */
1068 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1070 DCCP_BUG("empty loss history");
1072 if (hcrx->ccid3hcrx_p > p_prev) {
1073 ccid3_hc_rx_send_feedback(sk);
1078 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1080 struct dccp_sock *dp = dccp_sk(sk);
1081 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1083 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
1085 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
1086 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
1087 hcrx->ccid3hcrx_s = dp->dccps_packet_size;
1089 hcrx->ccid3hcrx_s = TFRC_STD_PACKET_SIZE;
1091 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1092 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1093 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1094 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1095 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1096 hcrx->ccid3hcrx_rtt = 5000; /* XXX 5ms for now... */
1100 static void ccid3_hc_rx_exit(struct sock *sk)
1102 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1104 BUG_ON(hcrx == NULL);
1106 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1108 /* Empty packet history */
1109 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1111 /* Empty loss interval history */
1112 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1115 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1117 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1119 /* Listen socks doesn't have a private CCID block */
1120 if (sk->sk_state == DCCP_LISTEN)
1123 BUG_ON(hcrx == NULL);
1125 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1126 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1127 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1130 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1132 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1134 /* Listen socks doesn't have a private CCID block */
1135 if (sk->sk_state == DCCP_LISTEN)
1138 BUG_ON(hctx == NULL);
1140 info->tcpi_rto = hctx->ccid3hctx_t_rto;
1141 info->tcpi_rtt = hctx->ccid3hctx_rtt;
1144 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1145 u32 __user *optval, int __user *optlen)
1147 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1150 /* Listen socks doesn't have a private CCID block */
1151 if (sk->sk_state == DCCP_LISTEN)
1155 case DCCP_SOCKOPT_CCID_RX_INFO:
1156 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1158 len = sizeof(hcrx->ccid3hcrx_tfrc);
1159 val = &hcrx->ccid3hcrx_tfrc;
1162 return -ENOPROTOOPT;
1165 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1171 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1172 u32 __user *optval, int __user *optlen)
1174 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1177 /* Listen socks doesn't have a private CCID block */
1178 if (sk->sk_state == DCCP_LISTEN)
1182 case DCCP_SOCKOPT_CCID_TX_INFO:
1183 if (len < sizeof(hctx->ccid3hctx_tfrc))
1185 len = sizeof(hctx->ccid3hctx_tfrc);
1186 val = &hctx->ccid3hctx_tfrc;
1189 return -ENOPROTOOPT;
1192 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1198 static struct ccid_operations ccid3 = {
1199 .ccid_id = DCCPC_CCID3,
1200 .ccid_name = "ccid3",
1201 .ccid_owner = THIS_MODULE,
1202 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1203 .ccid_hc_tx_init = ccid3_hc_tx_init,
1204 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1205 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1206 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1207 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1208 .ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
1209 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1210 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1211 .ccid_hc_rx_init = ccid3_hc_rx_init,
1212 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1213 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1214 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1215 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1216 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1217 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1218 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1221 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1222 module_param(ccid3_debug, int, 0444);
1223 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1226 static __init int ccid3_module_init(void)
1230 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1231 if (ccid3_rx_hist == NULL)
1234 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1235 if (ccid3_tx_hist == NULL)
1238 ccid3_li_hist = dccp_li_hist_new("ccid3");
1239 if (ccid3_li_hist == NULL)
1242 rc = ccid_register(&ccid3);
1244 goto out_free_loss_interval_history;
1248 out_free_loss_interval_history:
1249 dccp_li_hist_delete(ccid3_li_hist);
1250 ccid3_li_hist = NULL;
1252 dccp_tx_hist_delete(ccid3_tx_hist);
1253 ccid3_tx_hist = NULL;
1255 dccp_rx_hist_delete(ccid3_rx_hist);
1256 ccid3_rx_hist = NULL;
1259 module_init(ccid3_module_init);
1261 static __exit void ccid3_module_exit(void)
1263 ccid_unregister(&ccid3);
1265 if (ccid3_tx_hist != NULL) {
1266 dccp_tx_hist_delete(ccid3_tx_hist);
1267 ccid3_tx_hist = NULL;
1269 if (ccid3_rx_hist != NULL) {
1270 dccp_rx_hist_delete(ccid3_rx_hist);
1271 ccid3_rx_hist = NULL;
1273 if (ccid3_li_hist != NULL) {
1274 dccp_li_hist_delete(ccid3_li_hist);
1275 ccid3_li_hist = NULL;
1278 module_exit(ccid3_module_exit);
1280 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1281 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1282 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1283 MODULE_LICENSE("GPL");
1284 MODULE_ALIAS("net-dccp-ccid-3");