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 * If X has changed, we also update the scheduled send time t_now,
132 * the inter-packet interval t_ipi, and the delta value.
134 static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
137 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
138 const __u32 old_x = hctx->ccid3hctx_x;
140 if (hctx->ccid3hctx_p > 0) {
141 hctx->ccid3hctx_x = max_t(u32, min(hctx->ccid3hctx_x_calc,
142 hctx->ccid3hctx_x_recv * 2),
143 hctx->ccid3hctx_s / TFRC_T_MBI);
145 } else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) >=
146 hctx->ccid3hctx_rtt) {
147 hctx->ccid3hctx_x = max(min(hctx->ccid3hctx_x_recv,
148 hctx->ccid3hctx_x ) * 2,
149 usecs_div(hctx->ccid3hctx_s,
150 hctx->ccid3hctx_rtt) );
151 hctx->ccid3hctx_t_ld = *now;
154 if (hctx->ccid3hctx_x != old_x)
155 ccid3_update_send_time(hctx);
159 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
160 * @len: DCCP packet payload size in bytes
162 static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
164 if (unlikely(len == 0))
165 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
167 hctx->ccid3hctx_s = hctx->ccid3hctx_s == 0 ? len :
168 (9 * hctx->ccid3hctx_s + len) / 10;
170 * Note: We could do a potential optimisation here - when `s' changes,
171 * recalculate sending rate and consequently t_ipi, t_delta, and
172 * t_now. This is however non-standard, and the benefits are not
173 * clear, so it is currently left out.
177 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
179 struct sock *sk = (struct sock *)data;
180 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
181 unsigned long t_nfb = USEC_PER_SEC / 5;
184 if (sock_owned_by_user(sk)) {
185 /* Try again later. */
186 /* XXX: set some sensible MIB */
190 ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
191 ccid3_tx_state_name(hctx->ccid3hctx_state));
193 switch (hctx->ccid3hctx_state) {
194 case TFRC_SSTATE_NO_FBACK:
195 /* RFC 3448, 4.4: Halve send rate directly */
196 hctx->ccid3hctx_x = min_t(u32, hctx->ccid3hctx_x / 2,
197 hctx->ccid3hctx_s / TFRC_T_MBI);
199 ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %d "
202 ccid3_tx_state_name(hctx->ccid3hctx_state),
204 /* The value of R is still undefined and so we can not recompute
205 * the timout value. Keep initial value as per [RFC 4342, 5]. */
206 t_nfb = TFRC_INITIAL_TIMEOUT;
207 ccid3_update_send_time(hctx);
209 case TFRC_SSTATE_FBACK:
211 * Check if IDLE since last timeout and recv rate is less than
214 if (!hctx->ccid3hctx_idle ||
215 (hctx->ccid3hctx_x_recv >=
216 4 * usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt))) {
219 ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
221 ccid3_tx_state_name(hctx->ccid3hctx_state));
224 * Modify the cached value of X_recv [RFC 3448, 4.4]
226 * If (p == 0 || X_calc > 2 * X_recv)
227 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
229 * X_recv = X_calc / 4;
231 BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
233 if (hctx->ccid3hctx_p == 0 ||
234 hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv) {
235 hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2,
236 hctx->ccid3hctx_s / (2 * TFRC_T_MBI));
237 if (hctx->ccid3hctx_p == 0)
238 dccp_timestamp(sk, &now);
240 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc / 4;
242 /* Now recalculate X [RFC 3448, 4.3, step (4)] */
243 ccid3_hc_tx_update_x(sk, &now);
246 * Schedule no feedback timer to expire in
247 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
248 * See comments in packet_recv() regarding the value of t_RTO.
250 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
252 case TFRC_SSTATE_NO_SENT:
253 DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
255 case TFRC_SSTATE_TERM:
259 hctx->ccid3hctx_idle = 1;
262 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
263 jiffies + usecs_to_jiffies(t_nfb));
271 * > 0: delay (in msecs) that should pass before actually sending
272 * = 0: can send immediately
273 * < 0: error condition; do not send packet
275 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
277 struct dccp_sock *dp = dccp_sk(sk);
278 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
279 struct dccp_tx_hist_entry *new_packet;
283 BUG_ON(hctx == NULL);
286 * This function is called only for Data and DataAck packets. Sending
287 * zero-sized Data(Ack)s is theoretically possible, but for congestion
288 * control this case is pathological - ignore it.
290 if (unlikely(skb->len == 0))
293 /* See if last packet allocated was not sent */
294 new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
295 if (new_packet == NULL || new_packet->dccphtx_sent) {
296 new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
299 if (unlikely(new_packet == NULL)) {
300 DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
301 "send refused\n", dccp_role(sk), sk);
305 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
308 dccp_timestamp(sk, &now);
310 switch (hctx->ccid3hctx_state) {
311 case TFRC_SSTATE_NO_SENT:
312 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
313 jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
314 hctx->ccid3hctx_last_win_count = 0;
315 hctx->ccid3hctx_t_last_win_count = now;
316 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
318 /* Set initial sending rate to 1 packet per second */
319 ccid3_hc_tx_update_s(hctx, skb->len);
320 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
322 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
323 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
324 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
325 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
327 /* Set t_0 for initial packet */
328 hctx->ccid3hctx_t_nom = now;
330 case TFRC_SSTATE_NO_FBACK:
331 case TFRC_SSTATE_FBACK:
332 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
334 * Scheduling of packet transmissions [RFC 3448, 4.6]
336 * if (t_now > t_nom - delta)
337 * // send the packet now
339 * // send the packet in (t_nom - t_now) milliseconds.
341 if (delay - (long)hctx->ccid3hctx_delta >= 0)
342 return delay / 1000L;
344 case TFRC_SSTATE_TERM:
345 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
349 /* prepare to send now (add options etc.) */
350 dp->dccps_hc_tx_insert_options = 1;
351 new_packet->dccphtx_ccval = DCCP_SKB_CB(skb)->dccpd_ccval =
352 hctx->ccid3hctx_last_win_count;
353 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
358 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
360 const struct dccp_sock *dp = dccp_sk(sk);
361 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
363 unsigned long quarter_rtt;
364 struct dccp_tx_hist_entry *packet;
366 BUG_ON(hctx == NULL);
368 dccp_timestamp(sk, &now);
370 ccid3_hc_tx_update_s(hctx, len);
372 packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
373 if (unlikely(packet == NULL)) {
374 DCCP_WARN("packet doesn't exist in history!\n");
377 if (unlikely(packet->dccphtx_sent)) {
378 DCCP_WARN("no unsent packet in history!\n");
381 packet->dccphtx_tstamp = now;
382 packet->dccphtx_seqno = dp->dccps_gss;
384 * Check if win_count have changed
385 * Algorithm in "8.1. Window Counter Value" in RFC 4342.
387 quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
388 if (likely(hctx->ccid3hctx_rtt > 8))
389 quarter_rtt /= hctx->ccid3hctx_rtt / 4;
391 if (quarter_rtt > 0) {
392 hctx->ccid3hctx_t_last_win_count = now;
393 hctx->ccid3hctx_last_win_count = (hctx->ccid3hctx_last_win_count +
394 min_t(unsigned long, quarter_rtt, 5)) % 16;
395 ccid3_pr_debug("%s, sk=%p, window changed from "
398 packet->dccphtx_ccval,
399 hctx->ccid3hctx_last_win_count);
402 hctx->ccid3hctx_idle = 0;
403 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
404 packet->dccphtx_sent = 1;
407 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
409 const struct dccp_sock *dp = dccp_sk(sk);
410 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
411 struct ccid3_options_received *opt_recv;
412 struct dccp_tx_hist_entry *packet;
416 long r_sample, t_elapsed;
418 BUG_ON(hctx == NULL);
420 /* we are only interested in ACKs */
421 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
422 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
425 opt_recv = &hctx->ccid3hctx_options_received;
427 switch (hctx->ccid3hctx_state) {
428 case TFRC_SSTATE_NO_FBACK:
429 case TFRC_SSTATE_FBACK:
430 /* get packet from history to look up t_recvdata */
431 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
432 DCCP_SKB_CB(skb)->dccpd_ack_seq);
433 if (unlikely(packet == NULL)) {
434 DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
435 "in history!\n", dccp_role(sk), sk,
436 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
437 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
441 /* Update receive rate */
442 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
444 /* Update loss event rate */
445 pinv = opt_recv->ccid3or_loss_event_rate;
446 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
447 hctx->ccid3hctx_p = 0;
448 else /* can not exceed 100% */
449 hctx->ccid3hctx_p = 1000000 / pinv;
451 dccp_timestamp(sk, &now);
454 * Calculate new round trip sample as per [RFC 3448, 4.3] by
455 * R_sample = (now - t_recvdata) - t_elapsed
457 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
458 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
460 if (unlikely(r_sample <= 0)) {
461 DCCP_WARN("WARNING: R_sample (%ld) <= 0!\n", r_sample);
463 } else if (unlikely(r_sample <= t_elapsed))
464 DCCP_WARN("WARNING: r_sample=%ldus <= t_elapsed=%ldus\n",
465 r_sample, t_elapsed);
467 r_sample -= t_elapsed;
469 /* Update RTT estimate by
470 * If (No feedback recv)
473 * R = q * R + (1 - q) * R_sample;
475 * q is a constant, RFC 3448 recomments 0.9
477 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
478 /* Use Larger Initial Windows [RFC 4342, sec. 5]
479 * We deviate in that we use `s' instead of `MSS'. */
480 u16 w_init = max( 4 * hctx->ccid3hctx_s,
481 max(2 * hctx->ccid3hctx_s, 4380));
482 hctx->ccid3hctx_rtt = r_sample;
483 hctx->ccid3hctx_x = usecs_div(w_init, r_sample);
484 hctx->ccid3hctx_t_ld = now;
486 ccid3_update_send_time(hctx);
488 ccid3_pr_debug("%s(%p), s=%u, w_init=%u, "
489 "R_sample=%ldus, X=%u\n", dccp_role(sk),
490 sk, hctx->ccid3hctx_s, w_init, r_sample,
493 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
495 hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
496 (u32)r_sample ) / 10;
498 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
499 if (hctx->ccid3hctx_p > 0)
500 hctx->ccid3hctx_x_calc =
501 tfrc_calc_x(hctx->ccid3hctx_s,
504 ccid3_hc_tx_update_x(sk, &now);
506 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%ldus), s=%u, "
507 "p=%u, X_calc=%u, X=%u\n", dccp_role(sk),
508 sk, hctx->ccid3hctx_rtt, r_sample,
509 hctx->ccid3hctx_s, hctx->ccid3hctx_p,
510 hctx->ccid3hctx_x_calc,
514 /* unschedule no feedback timer */
515 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
517 /* remove all packets older than the one acked from history */
518 dccp_tx_hist_purge_older(ccid3_tx_hist,
519 &hctx->ccid3hctx_hist, packet);
521 * As we have calculated new ipi, delta, t_nom it is possible that
522 * we now can send a packet, so wake up dccp_wait_for_ccid
524 sk->sk_write_space(sk);
527 * Update timeout interval for the nofeedback timer.
528 * We use a configuration option to increase the lower bound.
529 * This can help avoid triggering the nofeedback timer too often
530 * ('spinning') on LANs with small RTTs.
532 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
533 CONFIG_IP_DCCP_CCID3_RTO *
534 (USEC_PER_SEC/1000) );
536 * Schedule no feedback timer to expire in
537 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
539 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
541 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
542 "expire in %lu jiffies (%luus)\n",
544 usecs_to_jiffies(t_nfb), t_nfb);
546 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
547 jiffies + usecs_to_jiffies(t_nfb));
550 hctx->ccid3hctx_idle = 1;
552 case TFRC_SSTATE_NO_SENT:
553 if (dccp_sk(sk)->dccps_role == DCCP_ROLE_CLIENT)
554 DCCP_WARN("Illegal ACK received - no packet sent\n");
556 case TFRC_SSTATE_TERM: /* ignore feedback when closing */
561 static int ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
563 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
565 BUG_ON(hctx == NULL);
567 if (sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)
568 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
572 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
573 unsigned char len, u16 idx,
574 unsigned char *value)
577 const struct dccp_sock *dp = dccp_sk(sk);
578 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
579 struct ccid3_options_received *opt_recv;
581 BUG_ON(hctx == NULL);
583 opt_recv = &hctx->ccid3hctx_options_received;
585 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
586 opt_recv->ccid3or_seqno = dp->dccps_gsr;
587 opt_recv->ccid3or_loss_event_rate = ~0;
588 opt_recv->ccid3or_loss_intervals_idx = 0;
589 opt_recv->ccid3or_loss_intervals_len = 0;
590 opt_recv->ccid3or_receive_rate = 0;
594 case TFRC_OPT_LOSS_EVENT_RATE:
595 if (unlikely(len != 4)) {
596 DCCP_WARN("%s, sk=%p, invalid len %d "
597 "for TFRC_OPT_LOSS_EVENT_RATE\n",
598 dccp_role(sk), sk, len);
601 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
602 ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
604 opt_recv->ccid3or_loss_event_rate);
607 case TFRC_OPT_LOSS_INTERVALS:
608 opt_recv->ccid3or_loss_intervals_idx = idx;
609 opt_recv->ccid3or_loss_intervals_len = len;
610 ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
612 opt_recv->ccid3or_loss_intervals_idx,
613 opt_recv->ccid3or_loss_intervals_len);
615 case TFRC_OPT_RECEIVE_RATE:
616 if (unlikely(len != 4)) {
617 DCCP_WARN("%s, sk=%p, invalid len %d "
618 "for TFRC_OPT_RECEIVE_RATE\n",
619 dccp_role(sk), sk, len);
622 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
623 ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
625 opt_recv->ccid3or_receive_rate);
633 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
635 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
637 hctx->ccid3hctx_s = 0;
638 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
639 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
641 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
642 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
643 init_timer(&hctx->ccid3hctx_no_feedback_timer);
648 static void ccid3_hc_tx_exit(struct sock *sk)
650 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
652 BUG_ON(hctx == NULL);
654 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
655 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
657 /* Empty packet history */
658 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
662 * RX Half Connection methods
665 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
666 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
668 static char *ccid3_rx_state_names[] = {
669 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
670 [TFRC_RSTATE_DATA] = "DATA",
671 [TFRC_RSTATE_TERM] = "TERM",
674 return ccid3_rx_state_names[state];
678 static void ccid3_hc_rx_set_state(struct sock *sk,
679 enum ccid3_hc_rx_states state)
681 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
682 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
684 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
685 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
686 ccid3_rx_state_name(state));
687 WARN_ON(state == oldstate);
688 hcrx->ccid3hcrx_state = state;
691 static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
693 if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
694 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
696 hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
697 (9 * hcrx->ccid3hcrx_s + len) / 10;
700 static void ccid3_hc_rx_send_feedback(struct sock *sk)
702 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
703 struct dccp_sock *dp = dccp_sk(sk);
704 struct dccp_rx_hist_entry *packet;
707 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
709 dccp_timestamp(sk, &now);
711 switch (hcrx->ccid3hcrx_state) {
712 case TFRC_RSTATE_NO_DATA:
713 hcrx->ccid3hcrx_x_recv = 0;
715 case TFRC_RSTATE_DATA: {
716 const u32 delta = timeval_delta(&now,
717 &hcrx->ccid3hcrx_tstamp_last_feedback);
718 hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
722 case TFRC_RSTATE_TERM:
723 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
727 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
728 if (unlikely(packet == NULL)) {
729 DCCP_WARN("%s, sk=%p, no data packet in history!\n",
734 hcrx->ccid3hcrx_tstamp_last_feedback = now;
735 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
736 hcrx->ccid3hcrx_bytes_recv = 0;
738 /* Convert to multiples of 10us */
739 hcrx->ccid3hcrx_elapsed_time =
740 timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
742 if (hcrx->ccid3hcrx_p == 0)
743 hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
744 else if (hcrx->ccid3hcrx_p > 1000000) {
745 DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
746 hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
748 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
750 dp->dccps_hc_rx_insert_options = 1;
754 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
756 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
759 BUG_ON(hcrx == NULL);
761 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
764 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
766 if (dccp_packet_without_ack(skb))
769 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
770 pinv = htonl(hcrx->ccid3hcrx_pinv);
772 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
773 dccp_insert_option_elapsed_time(sk, skb,
774 hcrx->ccid3hcrx_elapsed_time)) ||
775 dccp_insert_option_timestamp(sk, skb) ||
776 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
777 &pinv, sizeof(pinv)) ||
778 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
779 &x_recv, sizeof(x_recv)))
785 /* calculate first loss interval
787 * returns estimated loss interval in usecs */
789 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
791 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
792 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
793 u32 rtt, delta, x_recv, fval, p, tmp2;
794 struct timeval tstamp = { 0, };
800 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
802 if (dccp_rx_hist_entry_data_packet(entry)) {
807 tstamp = entry->dccphrx_tstamp;
808 win_count = entry->dccphrx_ccval;
812 interval = win_count - entry->dccphrx_ccval;
814 interval += TFRC_WIN_COUNT_LIMIT;
822 if (unlikely(step == 0)) {
823 DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
828 if (unlikely(interval == 0)) {
829 DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
830 "Defaulting to 1\n", dccp_role(sk), sk);
835 DCCP_CRIT("tail is null\n");
838 rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
839 ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
840 dccp_role(sk), sk, rtt);
843 DCCP_WARN("RTT==0, setting to 1\n");
847 dccp_timestamp(sk, &tstamp);
848 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
849 x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);
852 x_recv = hcrx->ccid3hcrx_x_recv;
854 tmp1 = (u64)x_recv * (u64)rtt;
855 do_div(tmp1,10000000);
859 DCCP_CRIT("tmp2 = 0, x_recv = %u, rtt =%u\n", x_recv, rtt);
863 fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
864 /* do not alter order above or you will get overflow on 32 bit */
865 p = tfrc_calc_x_reverse_lookup(fval);
866 ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
867 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
875 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
877 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
878 struct dccp_li_hist_entry *head;
881 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
882 if (!dccp_li_hist_interval_new(ccid3_li_hist,
883 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
886 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
887 struct dccp_li_hist_entry, dccplih_node);
888 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
890 struct dccp_li_hist_entry *entry;
891 struct list_head *tail;
893 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
894 struct dccp_li_hist_entry, dccplih_node);
895 /* FIXME win count check removed as was wrong */
896 /* should make this check with receive history */
897 /* and compare there as per section 10.2 of RFC4342 */
899 /* new loss event detected */
900 /* calculate last interval length */
901 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
902 entry = dccp_li_hist_entry_new(ccid3_li_hist, GFP_ATOMIC);
905 DCCP_BUG("out of memory - can not allocate entry");
909 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
911 tail = hcrx->ccid3hcrx_li_hist.prev;
913 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
915 /* Create the newest interval */
916 entry->dccplih_seqno = seq_loss;
917 entry->dccplih_interval = seq_temp;
918 entry->dccplih_win_count = win_loss;
922 static int ccid3_hc_rx_detect_loss(struct sock *sk,
923 struct dccp_rx_hist_entry *packet)
925 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
926 struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
927 u64 seqno = packet->dccphrx_seqno;
933 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
936 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
937 hcrx->ccid3hcrx_seqno_nonloss = seqno;
938 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
943 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
944 > TFRC_RECV_NUM_LATE_LOSS) {
946 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
947 hcrx->ccid3hcrx_ccval_nonloss);
948 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
949 dccp_inc_seqno(&tmp_seqno);
950 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
951 dccp_inc_seqno(&tmp_seqno);
952 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
953 tmp_seqno, &ccval)) {
954 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
955 hcrx->ccid3hcrx_ccval_nonloss = ccval;
956 dccp_inc_seqno(&tmp_seqno);
960 /* FIXME - this code could be simplified with above while */
961 /* but works at moment */
962 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
963 hcrx->ccid3hcrx_seqno_nonloss = seqno;
964 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
968 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
969 &hcrx->ccid3hcrx_li_hist, packet,
970 hcrx->ccid3hcrx_seqno_nonloss);
974 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
976 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
977 const struct dccp_options_received *opt_recv;
978 struct dccp_rx_hist_entry *packet;
980 u32 p_prev, rtt_prev, r_sample, t_elapsed;
981 int loss, payload_size;
983 BUG_ON(hcrx == NULL);
985 opt_recv = &dccp_sk(sk)->dccps_options_received;
987 switch (DCCP_SKB_CB(skb)->dccpd_type) {
989 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
991 case DCCP_PKT_DATAACK:
992 if (opt_recv->dccpor_timestamp_echo == 0)
994 rtt_prev = hcrx->ccid3hcrx_rtt;
995 dccp_timestamp(sk, &now);
996 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
997 r_sample = timeval_usecs(&now);
998 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
1000 if (unlikely(r_sample <= t_elapsed))
1001 DCCP_WARN("r_sample=%uus, t_elapsed=%uus\n",
1002 r_sample, t_elapsed);
1004 r_sample -= t_elapsed;
1006 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1007 hcrx->ccid3hcrx_rtt = r_sample;
1009 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
1012 if (rtt_prev != hcrx->ccid3hcrx_rtt)
1013 ccid3_pr_debug("%s, New RTT=%uus, elapsed time=%u\n",
1014 dccp_role(sk), hcrx->ccid3hcrx_rtt,
1015 opt_recv->dccpor_elapsed_time);
1019 default: /* We're not interested in other packet types, move along */
1023 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
1025 if (unlikely(packet == NULL)) {
1026 DCCP_WARN("%s, sk=%p, Not enough mem to add rx packet "
1027 "to history, consider it lost!\n", dccp_role(sk), sk);
1031 loss = ccid3_hc_rx_detect_loss(sk, packet);
1033 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1036 payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
1037 ccid3_hc_rx_update_s(hcrx, payload_size);
1039 switch (hcrx->ccid3hcrx_state) {
1040 case TFRC_RSTATE_NO_DATA:
1041 ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial "
1044 dccp_state_name(sk->sk_state), skb);
1045 ccid3_hc_rx_send_feedback(sk);
1046 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1048 case TFRC_RSTATE_DATA:
1049 hcrx->ccid3hcrx_bytes_recv += payload_size;
1053 dccp_timestamp(sk, &now);
1054 if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
1055 hcrx->ccid3hcrx_rtt) {
1056 hcrx->ccid3hcrx_tstamp_last_ack = now;
1057 ccid3_hc_rx_send_feedback(sk);
1060 case TFRC_RSTATE_TERM:
1061 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
1065 /* Dealing with packet loss */
1066 ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n",
1067 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1069 p_prev = hcrx->ccid3hcrx_p;
1071 /* Calculate loss event rate */
1072 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1073 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1075 /* Scaling up by 1000000 as fixed decimal */
1077 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1079 DCCP_BUG("empty loss history");
1081 if (hcrx->ccid3hcrx_p > p_prev) {
1082 ccid3_hc_rx_send_feedback(sk);
1087 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1089 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1091 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
1093 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1094 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1095 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1096 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1097 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1098 hcrx->ccid3hcrx_s = 0;
1099 hcrx->ccid3hcrx_rtt = 5000; /* XXX 5ms for now... */
1103 static void ccid3_hc_rx_exit(struct sock *sk)
1105 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1107 BUG_ON(hcrx == NULL);
1109 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1111 /* Empty packet history */
1112 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1114 /* Empty loss interval history */
1115 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1118 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1120 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1122 /* Listen socks doesn't have a private CCID block */
1123 if (sk->sk_state == DCCP_LISTEN)
1126 BUG_ON(hcrx == NULL);
1128 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1129 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1130 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1133 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1135 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1137 /* Listen socks doesn't have a private CCID block */
1138 if (sk->sk_state == DCCP_LISTEN)
1141 BUG_ON(hctx == NULL);
1143 info->tcpi_rto = hctx->ccid3hctx_t_rto;
1144 info->tcpi_rtt = hctx->ccid3hctx_rtt;
1147 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1148 u32 __user *optval, int __user *optlen)
1150 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1153 /* Listen socks doesn't have a private CCID block */
1154 if (sk->sk_state == DCCP_LISTEN)
1158 case DCCP_SOCKOPT_CCID_RX_INFO:
1159 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1161 len = sizeof(hcrx->ccid3hcrx_tfrc);
1162 val = &hcrx->ccid3hcrx_tfrc;
1165 return -ENOPROTOOPT;
1168 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1174 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1175 u32 __user *optval, int __user *optlen)
1177 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1180 /* Listen socks doesn't have a private CCID block */
1181 if (sk->sk_state == DCCP_LISTEN)
1185 case DCCP_SOCKOPT_CCID_TX_INFO:
1186 if (len < sizeof(hctx->ccid3hctx_tfrc))
1188 len = sizeof(hctx->ccid3hctx_tfrc);
1189 val = &hctx->ccid3hctx_tfrc;
1192 return -ENOPROTOOPT;
1195 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1201 static struct ccid_operations ccid3 = {
1202 .ccid_id = DCCPC_CCID3,
1203 .ccid_name = "ccid3",
1204 .ccid_owner = THIS_MODULE,
1205 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1206 .ccid_hc_tx_init = ccid3_hc_tx_init,
1207 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1208 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1209 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1210 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1211 .ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
1212 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1213 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1214 .ccid_hc_rx_init = ccid3_hc_rx_init,
1215 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1216 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1217 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1218 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1219 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1220 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1221 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1224 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1225 module_param(ccid3_debug, int, 0444);
1226 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1229 static __init int ccid3_module_init(void)
1233 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1234 if (ccid3_rx_hist == NULL)
1237 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1238 if (ccid3_tx_hist == NULL)
1241 ccid3_li_hist = dccp_li_hist_new("ccid3");
1242 if (ccid3_li_hist == NULL)
1245 rc = ccid_register(&ccid3);
1247 goto out_free_loss_interval_history;
1251 out_free_loss_interval_history:
1252 dccp_li_hist_delete(ccid3_li_hist);
1253 ccid3_li_hist = NULL;
1255 dccp_tx_hist_delete(ccid3_tx_hist);
1256 ccid3_tx_hist = NULL;
1258 dccp_rx_hist_delete(ccid3_rx_hist);
1259 ccid3_rx_hist = NULL;
1262 module_init(ccid3_module_init);
1264 static __exit void ccid3_module_exit(void)
1266 ccid_unregister(&ccid3);
1268 if (ccid3_tx_hist != NULL) {
1269 dccp_tx_hist_delete(ccid3_tx_hist);
1270 ccid3_tx_hist = NULL;
1272 if (ccid3_rx_hist != NULL) {
1273 dccp_rx_hist_delete(ccid3_rx_hist);
1274 ccid3_rx_hist = NULL;
1276 if (ccid3_li_hist != NULL) {
1277 dccp_li_hist_delete(ccid3_li_hist);
1278 ccid3_li_hist = NULL;
1281 module_exit(ccid3_module_exit);
1283 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1284 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1285 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1286 MODULE_LICENSE("GPL");
1287 MODULE_ALIAS("net-dccp-ccid-3");