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;
104 * Recalculate scheduled nominal send time t_nom, inter-packet interval
105 * t_ipi, and delta value. Should be called after each change to X.
107 static inline void ccid3_update_send_time(struct ccid3_hc_tx_sock *hctx)
109 timeval_sub_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
111 /* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */
112 hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_x);
114 /* Update nominal send time with regard to the new t_ipi */
115 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
117 /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
118 hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
119 TFRC_OPSYS_HALF_TIME_GRAN);
124 * x_calc = calcX(s, R, p);
125 * X = max(min(X_calc, 2 * X_recv), s / t_mbi);
127 * If (now - tld >= R)
128 * X = max(min(2 * X, 2 * X_recv), s / R);
131 static void ccid3_hc_tx_update_x(struct sock *sk)
133 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
134 const __u32 old_x = hctx->ccid3hctx_x;
136 /* To avoid large error in calcX */
137 if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) {
138 hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s,
141 hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_calc,
142 2 * hctx->ccid3hctx_x_recv),
144 TFRC_MAX_BACK_OFF_TIME));
148 dccp_timestamp(sk, &now);
149 if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >=
150 hctx->ccid3hctx_rtt) {
151 hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_recv,
152 hctx->ccid3hctx_x) * 2,
153 usecs_div(hctx->ccid3hctx_s,
154 hctx->ccid3hctx_rtt));
155 hctx->ccid3hctx_t_ld = now;
158 if (hctx->ccid3hctx_x != old_x)
159 ccid3_update_send_time(hctx);
162 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
164 struct sock *sk = (struct sock *)data;
165 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
166 unsigned long next_tmout = USEC_PER_SEC / 5;
169 if (sock_owned_by_user(sk)) {
170 /* Try again later. */
171 /* XXX: set some sensible MIB */
175 ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
176 ccid3_tx_state_name(hctx->ccid3hctx_state));
178 switch (hctx->ccid3hctx_state) {
179 case TFRC_SSTATE_NO_FBACK:
180 /* Halve send rate */
181 hctx->ccid3hctx_x /= 2;
182 if (hctx->ccid3hctx_x < (hctx->ccid3hctx_s /
183 TFRC_MAX_BACK_OFF_TIME))
184 hctx->ccid3hctx_x = (hctx->ccid3hctx_s /
185 TFRC_MAX_BACK_OFF_TIME);
187 ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %d "
190 ccid3_tx_state_name(hctx->ccid3hctx_state),
192 /* The value of R is still undefined and so we can not recompute
193 * the timout value. Keep initial value as per [RFC 4342, 5]. */
194 next_tmout = TFRC_INITIAL_TIMEOUT;
195 ccid3_update_send_time(hctx);
197 case TFRC_SSTATE_FBACK:
199 * Check if IDLE since last timeout and recv rate is less than
202 if (!hctx->ccid3hctx_idle ||
203 (hctx->ccid3hctx_x_recv >=
204 4 * usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt))) {
205 ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
207 ccid3_tx_state_name(hctx->ccid3hctx_state));
208 /* Halve sending rate */
210 /* If (X_calc > 2 * X_recv)
211 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
213 * X_recv = X_calc / 4;
215 BUG_ON(hctx->ccid3hctx_p >= TFRC_SMALLEST_P &&
216 hctx->ccid3hctx_x_calc == 0);
218 /* check also if p is zero -> x_calc is infinity? */
219 if (hctx->ccid3hctx_p < TFRC_SMALLEST_P ||
220 hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv)
221 hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2,
222 hctx->ccid3hctx_s / (2 * TFRC_MAX_BACK_OFF_TIME));
224 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc / 4;
226 /* Update sending rate */
227 ccid3_hc_tx_update_x(sk);
230 * Schedule no feedback timer to expire in
231 * max(4 * R, 2 * s / X)
233 next_tmout = max_t(u32, hctx->ccid3hctx_t_rto,
234 2 * usecs_div(hctx->ccid3hctx_s,
237 case TFRC_SSTATE_NO_SENT:
238 DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
240 case TFRC_SSTATE_TERM:
244 hctx->ccid3hctx_idle = 1;
247 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
248 jiffies + usecs_to_jiffies(next_tmout));
256 * > 0: delay (in msecs) that should pass before actually sending
257 * = 0: can send immediately
258 * < 0: error condition; do not send packet
260 static int ccid3_hc_tx_send_packet(struct sock *sk,
261 struct sk_buff *skb, int len)
263 struct dccp_sock *dp = dccp_sk(sk);
264 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
265 struct dccp_tx_hist_entry *new_packet;
269 BUG_ON(hctx == NULL);
272 * This function is called only for Data and DataAck packets. Sending
273 * zero-sized Data(Ack)s is theoretically possible, but for congestion
274 * control this case is pathological - ignore it.
276 if (unlikely(len == 0))
279 /* See if last packet allocated was not sent */
280 new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
281 if (new_packet == NULL || new_packet->dccphtx_sent) {
282 new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
285 if (unlikely(new_packet == NULL)) {
286 DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
287 "send refused\n", dccp_role(sk), sk);
291 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
294 dccp_timestamp(sk, &now);
296 switch (hctx->ccid3hctx_state) {
297 case TFRC_SSTATE_NO_SENT:
298 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
299 jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
300 hctx->ccid3hctx_last_win_count = 0;
301 hctx->ccid3hctx_t_last_win_count = now;
302 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
304 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
305 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
306 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
307 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
309 /* Set t_0 for initial packet */
310 hctx->ccid3hctx_t_nom = now;
312 case TFRC_SSTATE_NO_FBACK:
313 case TFRC_SSTATE_FBACK:
314 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
316 * Scheduling of packet transmissions [RFC 3448, 4.6]
318 * if (t_now > t_nom - delta)
319 * // send the packet now
321 * // send the packet in (t_nom - t_now) milliseconds.
323 if (delay >= hctx->ccid3hctx_delta)
324 return delay / 1000L;
326 case TFRC_SSTATE_TERM:
327 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
331 /* prepare to send now (add options etc.) */
332 dp->dccps_hc_tx_insert_options = 1;
333 new_packet->dccphtx_ccval = DCCP_SKB_CB(skb)->dccpd_ccval =
334 hctx->ccid3hctx_last_win_count;
335 timeval_add_usecs(&hctx->ccid3hctx_t_nom, 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);
393 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
395 const struct dccp_sock *dp = dccp_sk(sk);
396 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
397 struct ccid3_options_received *opt_recv;
398 struct dccp_tx_hist_entry *packet;
400 unsigned long next_tmout;
406 BUG_ON(hctx == NULL);
408 /* we are only interested in ACKs */
409 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
410 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
413 opt_recv = &hctx->ccid3hctx_options_received;
415 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
416 x_recv = opt_recv->ccid3or_receive_rate;
417 pinv = opt_recv->ccid3or_loss_event_rate;
419 switch (hctx->ccid3hctx_state) {
420 case TFRC_SSTATE_NO_FBACK:
421 case TFRC_SSTATE_FBACK:
422 /* Calculate new round trip sample by
423 * R_sample = (now - t_recvdata) - t_delay */
424 /* get t_recvdata from history */
425 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
426 DCCP_SKB_CB(skb)->dccpd_ack_seq);
427 if (unlikely(packet == NULL)) {
428 DCCP_WARN("%s, sk=%p, seqno %llu(%s) does't exist "
429 "in history!\n", dccp_role(sk), sk,
430 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
431 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
436 dccp_timestamp(sk, &now);
437 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
438 if (unlikely(r_sample <= t_elapsed))
439 DCCP_WARN("r_sample=%uus,t_elapsed=%uus\n",
440 r_sample, t_elapsed);
442 r_sample -= t_elapsed;
444 /* Update RTT estimate by
445 * If (No feedback recv)
448 * R = q * R + (1 - q) * R_sample;
450 * q is a constant, RFC 3448 recomments 0.9
452 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
453 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
454 hctx->ccid3hctx_rtt = r_sample;
456 hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
459 ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
460 "r_sample=%us\n", dccp_role(sk), sk,
461 hctx->ccid3hctx_rtt, r_sample);
463 /* Update timeout interval */
464 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
467 /* Update receive rate */
468 hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
470 /* Update loss event rate */
471 if (pinv == ~0 || pinv == 0)
472 hctx->ccid3hctx_p = 0;
474 hctx->ccid3hctx_p = 1000000 / pinv;
476 if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
477 hctx->ccid3hctx_p = TFRC_SMALLEST_P;
478 ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
483 /* unschedule no feedback timer */
484 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
486 /* Update sending rate (and likely t_ipi, t_nom, and delta) */
487 ccid3_hc_tx_update_x(sk);
489 /* remove all packets older than the one acked from history */
490 dccp_tx_hist_purge_older(ccid3_tx_hist,
491 &hctx->ccid3hctx_hist, packet);
493 * As we have calculated new ipi, delta, t_nom it is possible that
494 * we now can send a packet, so wake up dccp_wait_for_ccids.
496 sk->sk_write_space(sk);
499 * Schedule no feedback timer to expire in
500 * max(4 * R, 2 * s / X)
502 next_tmout = max(hctx->ccid3hctx_t_rto,
503 2 * usecs_div(hctx->ccid3hctx_s,
506 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
507 "expire in %lu jiffies (%luus)\n",
509 usecs_to_jiffies(next_tmout), next_tmout);
511 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
512 jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
515 hctx->ccid3hctx_idle = 1;
517 case TFRC_SSTATE_NO_SENT:
518 DCCP_WARN("Illegal ACK received - no packet has been sent\n");
520 case TFRC_SSTATE_TERM: /* ignore feedback when closing */
525 static int ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
527 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
529 BUG_ON(hctx == NULL);
531 if (sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)
532 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
536 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
537 unsigned char len, u16 idx,
538 unsigned char *value)
541 const struct dccp_sock *dp = dccp_sk(sk);
542 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
543 struct ccid3_options_received *opt_recv;
545 BUG_ON(hctx == NULL);
547 opt_recv = &hctx->ccid3hctx_options_received;
549 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
550 opt_recv->ccid3or_seqno = dp->dccps_gsr;
551 opt_recv->ccid3or_loss_event_rate = ~0;
552 opt_recv->ccid3or_loss_intervals_idx = 0;
553 opt_recv->ccid3or_loss_intervals_len = 0;
554 opt_recv->ccid3or_receive_rate = 0;
558 case TFRC_OPT_LOSS_EVENT_RATE:
559 if (unlikely(len != 4)) {
560 DCCP_WARN("%s, sk=%p, invalid len %d "
561 "for TFRC_OPT_LOSS_EVENT_RATE\n",
562 dccp_role(sk), sk, len);
565 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
566 ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
568 opt_recv->ccid3or_loss_event_rate);
571 case TFRC_OPT_LOSS_INTERVALS:
572 opt_recv->ccid3or_loss_intervals_idx = idx;
573 opt_recv->ccid3or_loss_intervals_len = len;
574 ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
576 opt_recv->ccid3or_loss_intervals_idx,
577 opt_recv->ccid3or_loss_intervals_len);
579 case TFRC_OPT_RECEIVE_RATE:
580 if (unlikely(len != 4)) {
581 DCCP_WARN("%s, sk=%p, invalid len %d "
582 "for TFRC_OPT_RECEIVE_RATE\n",
583 dccp_role(sk), sk, len);
586 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
587 ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
589 opt_recv->ccid3or_receive_rate);
597 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
599 struct dccp_sock *dp = dccp_sk(sk);
600 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
602 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
603 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
604 hctx->ccid3hctx_s = dp->dccps_packet_size;
606 hctx->ccid3hctx_s = TFRC_STD_PACKET_SIZE;
608 /* Set transmission rate to 1 packet per second */
609 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
610 hctx->ccid3hctx_t_rto = USEC_PER_SEC;
611 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
612 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
614 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
615 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
616 init_timer(&hctx->ccid3hctx_no_feedback_timer);
621 static void ccid3_hc_tx_exit(struct sock *sk)
623 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
625 BUG_ON(hctx == NULL);
627 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
628 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
630 /* Empty packet history */
631 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
635 * RX Half Connection methods
638 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
639 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
641 static char *ccid3_rx_state_names[] = {
642 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
643 [TFRC_RSTATE_DATA] = "DATA",
644 [TFRC_RSTATE_TERM] = "TERM",
647 return ccid3_rx_state_names[state];
651 static void ccid3_hc_rx_set_state(struct sock *sk,
652 enum ccid3_hc_rx_states state)
654 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
655 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
657 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
658 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
659 ccid3_rx_state_name(state));
660 WARN_ON(state == oldstate);
661 hcrx->ccid3hcrx_state = state;
664 static void ccid3_hc_rx_send_feedback(struct sock *sk)
666 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
667 struct dccp_sock *dp = dccp_sk(sk);
668 struct dccp_rx_hist_entry *packet;
671 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
673 dccp_timestamp(sk, &now);
675 switch (hcrx->ccid3hcrx_state) {
676 case TFRC_RSTATE_NO_DATA:
677 hcrx->ccid3hcrx_x_recv = 0;
679 case TFRC_RSTATE_DATA: {
680 const u32 delta = timeval_delta(&now,
681 &hcrx->ccid3hcrx_tstamp_last_feedback);
682 hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
686 case TFRC_RSTATE_TERM:
687 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
691 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
692 if (unlikely(packet == NULL)) {
693 DCCP_WARN("%s, sk=%p, no data packet in history!\n",
698 hcrx->ccid3hcrx_tstamp_last_feedback = now;
699 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
700 hcrx->ccid3hcrx_bytes_recv = 0;
702 /* Convert to multiples of 10us */
703 hcrx->ccid3hcrx_elapsed_time =
704 timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
705 if (hcrx->ccid3hcrx_p == 0)
706 hcrx->ccid3hcrx_pinv = ~0;
708 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
709 dp->dccps_hc_rx_insert_options = 1;
713 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
715 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
718 BUG_ON(hcrx == NULL);
720 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
723 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
725 if (dccp_packet_without_ack(skb))
728 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
729 pinv = htonl(hcrx->ccid3hcrx_pinv);
731 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
732 dccp_insert_option_elapsed_time(sk, skb,
733 hcrx->ccid3hcrx_elapsed_time)) ||
734 dccp_insert_option_timestamp(sk, skb) ||
735 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
736 &pinv, sizeof(pinv)) ||
737 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
738 &x_recv, sizeof(x_recv)))
744 /* calculate first loss interval
746 * returns estimated loss interval in usecs */
748 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
750 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
751 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
752 u32 rtt, delta, x_recv, fval, p, tmp2;
753 struct timeval tstamp = { 0, };
759 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
761 if (dccp_rx_hist_entry_data_packet(entry)) {
766 tstamp = entry->dccphrx_tstamp;
767 win_count = entry->dccphrx_ccval;
771 interval = win_count - entry->dccphrx_ccval;
773 interval += TFRC_WIN_COUNT_LIMIT;
781 if (unlikely(step == 0)) {
782 DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
787 if (unlikely(interval == 0)) {
788 DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
789 "Defaulting to 1\n", dccp_role(sk), sk);
794 DCCP_CRIT("tail is null\n");
797 rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
798 ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
799 dccp_role(sk), sk, rtt);
802 DCCP_WARN("RTT==0, setting to 1\n");
806 dccp_timestamp(sk, &tstamp);
807 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
808 x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);
811 x_recv = hcrx->ccid3hcrx_x_recv;
813 tmp1 = (u64)x_recv * (u64)rtt;
814 do_div(tmp1,10000000);
818 DCCP_CRIT("tmp2 = 0, x_recv = %u, rtt =%u\n", x_recv, rtt);
822 fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
823 /* do not alter order above or you will get overflow on 32 bit */
824 p = tfrc_calc_x_reverse_lookup(fval);
825 ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
826 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
834 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
836 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
837 struct dccp_li_hist_entry *head;
840 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
841 if (!dccp_li_hist_interval_new(ccid3_li_hist,
842 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
845 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
846 struct dccp_li_hist_entry, dccplih_node);
847 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
849 struct dccp_li_hist_entry *entry;
850 struct list_head *tail;
852 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
853 struct dccp_li_hist_entry, dccplih_node);
854 /* FIXME win count check removed as was wrong */
855 /* should make this check with receive history */
856 /* and compare there as per section 10.2 of RFC4342 */
858 /* new loss event detected */
859 /* calculate last interval length */
860 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
861 entry = dccp_li_hist_entry_new(ccid3_li_hist, SLAB_ATOMIC);
864 DCCP_BUG("out of memory - can not allocate entry");
868 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
870 tail = hcrx->ccid3hcrx_li_hist.prev;
872 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
874 /* Create the newest interval */
875 entry->dccplih_seqno = seq_loss;
876 entry->dccplih_interval = seq_temp;
877 entry->dccplih_win_count = win_loss;
881 static int ccid3_hc_rx_detect_loss(struct sock *sk,
882 struct dccp_rx_hist_entry *packet)
884 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
885 struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
886 u64 seqno = packet->dccphrx_seqno;
892 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
895 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
896 hcrx->ccid3hcrx_seqno_nonloss = seqno;
897 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
902 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
903 > TFRC_RECV_NUM_LATE_LOSS) {
905 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
906 hcrx->ccid3hcrx_ccval_nonloss);
907 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
908 dccp_inc_seqno(&tmp_seqno);
909 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
910 dccp_inc_seqno(&tmp_seqno);
911 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
912 tmp_seqno, &ccval)) {
913 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
914 hcrx->ccid3hcrx_ccval_nonloss = ccval;
915 dccp_inc_seqno(&tmp_seqno);
919 /* FIXME - this code could be simplified with above while */
920 /* but works at moment */
921 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
922 hcrx->ccid3hcrx_seqno_nonloss = seqno;
923 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
927 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
928 &hcrx->ccid3hcrx_li_hist, packet,
929 hcrx->ccid3hcrx_seqno_nonloss);
933 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
935 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
936 const struct dccp_options_received *opt_recv;
937 struct dccp_rx_hist_entry *packet;
939 u32 p_prev, rtt_prev, r_sample, t_elapsed;
942 BUG_ON(hcrx == NULL);
944 opt_recv = &dccp_sk(sk)->dccps_options_received;
946 switch (DCCP_SKB_CB(skb)->dccpd_type) {
948 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
950 case DCCP_PKT_DATAACK:
951 if (opt_recv->dccpor_timestamp_echo == 0)
953 rtt_prev = hcrx->ccid3hcrx_rtt;
954 dccp_timestamp(sk, &now);
955 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
956 r_sample = timeval_usecs(&now);
957 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
959 if (unlikely(r_sample <= t_elapsed))
960 DCCP_WARN("r_sample=%uus, t_elapsed=%uus\n",
961 r_sample, t_elapsed);
963 r_sample -= t_elapsed;
965 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
966 hcrx->ccid3hcrx_rtt = r_sample;
968 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
971 if (rtt_prev != hcrx->ccid3hcrx_rtt)
972 ccid3_pr_debug("%s, New RTT=%uus, elapsed time=%u\n",
973 dccp_role(sk), hcrx->ccid3hcrx_rtt,
974 opt_recv->dccpor_elapsed_time);
978 default: /* We're not interested in other packet types, move along */
982 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
984 if (unlikely(packet == NULL)) {
985 DCCP_WARN("%s, sk=%p, Not enough mem to add rx packet "
986 "to history, consider it lost!\n", dccp_role(sk), sk);
990 loss = ccid3_hc_rx_detect_loss(sk, packet);
992 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
995 switch (hcrx->ccid3hcrx_state) {
996 case TFRC_RSTATE_NO_DATA:
997 ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial "
1000 dccp_state_name(sk->sk_state), skb);
1001 ccid3_hc_rx_send_feedback(sk);
1002 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1004 case TFRC_RSTATE_DATA:
1005 hcrx->ccid3hcrx_bytes_recv += skb->len -
1006 dccp_hdr(skb)->dccph_doff * 4;
1010 dccp_timestamp(sk, &now);
1011 if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
1012 hcrx->ccid3hcrx_rtt) {
1013 hcrx->ccid3hcrx_tstamp_last_ack = now;
1014 ccid3_hc_rx_send_feedback(sk);
1017 case TFRC_RSTATE_TERM:
1018 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
1022 /* Dealing with packet loss */
1023 ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n",
1024 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1026 p_prev = hcrx->ccid3hcrx_p;
1028 /* Calculate loss event rate */
1029 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1030 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1032 /* Scaling up by 1000000 as fixed decimal */
1034 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1036 DCCP_BUG("empty loss history");
1038 if (hcrx->ccid3hcrx_p > p_prev) {
1039 ccid3_hc_rx_send_feedback(sk);
1044 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1046 struct dccp_sock *dp = dccp_sk(sk);
1047 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1049 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
1051 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
1052 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
1053 hcrx->ccid3hcrx_s = dp->dccps_packet_size;
1055 hcrx->ccid3hcrx_s = TFRC_STD_PACKET_SIZE;
1057 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1058 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1059 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1060 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1061 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1062 hcrx->ccid3hcrx_rtt = 5000; /* XXX 5ms for now... */
1066 static void ccid3_hc_rx_exit(struct sock *sk)
1068 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1070 BUG_ON(hcrx == NULL);
1072 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1074 /* Empty packet history */
1075 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1077 /* Empty loss interval history */
1078 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1081 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1083 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1085 /* Listen socks doesn't have a private CCID block */
1086 if (sk->sk_state == DCCP_LISTEN)
1089 BUG_ON(hcrx == NULL);
1091 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1092 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1093 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1096 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1098 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1100 /* Listen socks doesn't have a private CCID block */
1101 if (sk->sk_state == DCCP_LISTEN)
1104 BUG_ON(hctx == NULL);
1106 info->tcpi_rto = hctx->ccid3hctx_t_rto;
1107 info->tcpi_rtt = hctx->ccid3hctx_rtt;
1110 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1111 u32 __user *optval, int __user *optlen)
1113 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1116 /* Listen socks doesn't have a private CCID block */
1117 if (sk->sk_state == DCCP_LISTEN)
1121 case DCCP_SOCKOPT_CCID_RX_INFO:
1122 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1124 len = sizeof(hcrx->ccid3hcrx_tfrc);
1125 val = &hcrx->ccid3hcrx_tfrc;
1128 return -ENOPROTOOPT;
1131 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1137 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1138 u32 __user *optval, int __user *optlen)
1140 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1143 /* Listen socks doesn't have a private CCID block */
1144 if (sk->sk_state == DCCP_LISTEN)
1148 case DCCP_SOCKOPT_CCID_TX_INFO:
1149 if (len < sizeof(hctx->ccid3hctx_tfrc))
1151 len = sizeof(hctx->ccid3hctx_tfrc);
1152 val = &hctx->ccid3hctx_tfrc;
1155 return -ENOPROTOOPT;
1158 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1164 static struct ccid_operations ccid3 = {
1165 .ccid_id = DCCPC_CCID3,
1166 .ccid_name = "ccid3",
1167 .ccid_owner = THIS_MODULE,
1168 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1169 .ccid_hc_tx_init = ccid3_hc_tx_init,
1170 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1171 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1172 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1173 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1174 .ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
1175 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1176 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1177 .ccid_hc_rx_init = ccid3_hc_rx_init,
1178 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1179 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1180 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1181 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1182 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1183 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1184 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1187 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1188 module_param(ccid3_debug, int, 0444);
1189 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1192 static __init int ccid3_module_init(void)
1196 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1197 if (ccid3_rx_hist == NULL)
1200 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1201 if (ccid3_tx_hist == NULL)
1204 ccid3_li_hist = dccp_li_hist_new("ccid3");
1205 if (ccid3_li_hist == NULL)
1208 rc = ccid_register(&ccid3);
1210 goto out_free_loss_interval_history;
1214 out_free_loss_interval_history:
1215 dccp_li_hist_delete(ccid3_li_hist);
1216 ccid3_li_hist = NULL;
1218 dccp_tx_hist_delete(ccid3_tx_hist);
1219 ccid3_tx_hist = NULL;
1221 dccp_rx_hist_delete(ccid3_rx_hist);
1222 ccid3_rx_hist = NULL;
1225 module_init(ccid3_module_init);
1227 static __exit void ccid3_module_exit(void)
1229 ccid_unregister(&ccid3);
1231 if (ccid3_tx_hist != NULL) {
1232 dccp_tx_hist_delete(ccid3_tx_hist);
1233 ccid3_tx_hist = NULL;
1235 if (ccid3_rx_hist != NULL) {
1236 dccp_rx_hist_delete(ccid3_rx_hist);
1237 ccid3_rx_hist = NULL;
1239 if (ccid3_li_hist != NULL) {
1240 dccp_li_hist_delete(ccid3_li_hist);
1241 ccid3_li_hist = NULL;
1244 module_exit(ccid3_module_exit);
1246 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1247 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1248 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1249 MODULE_LICENSE("GPL");
1250 MODULE_ALIAS("net-dccp-ccid-3");