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.
38 #include "lib/packet_history.h"
39 #include "lib/loss_interval.h"
43 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
44 static int ccid3_debug;
45 #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
47 #define ccid3_pr_debug(format, a...)
50 static struct dccp_tx_hist *ccid3_tx_hist;
51 static struct dccp_rx_hist *ccid3_rx_hist;
52 static struct dccp_li_hist *ccid3_li_hist;
55 * Transmitter Half-Connection Routines
57 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
58 static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
60 static char *ccid3_state_names[] = {
61 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
62 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
63 [TFRC_SSTATE_FBACK] = "FBACK",
64 [TFRC_SSTATE_TERM] = "TERM",
67 return ccid3_state_names[state];
71 static void ccid3_hc_tx_set_state(struct sock *sk,
72 enum ccid3_hc_tx_states state)
74 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
75 enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
77 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
78 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
79 ccid3_tx_state_name(state));
80 WARN_ON(state == oldstate);
81 hctx->ccid3hctx_state = state;
85 * Compute the initial sending rate X_init according to RFC 3390:
86 * w_init = min(4 * MSS, max(2 * MSS, 4380 bytes))
87 * X_init = w_init / RTT
88 * For consistency with other parts of the code, X_init is scaled by 2^6.
90 static inline u64 rfc3390_initial_rate(struct sock *sk)
92 const struct dccp_sock *dp = dccp_sk(sk);
93 const __u32 w_init = min(4 * dp->dccps_mss_cache,
94 max(2 * dp->dccps_mss_cache, 4380U));
96 return scaled_div(w_init << 6, ccid3_hc_tx_sk(sk)->ccid3hctx_rtt);
100 * Recalculate t_ipi and delta (should be called whenever X changes)
102 static inline void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx)
104 /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
105 hctx->ccid3hctx_t_ipi = scaled_div(hctx->ccid3hctx_s,
106 hctx->ccid3hctx_x >> 6);
108 /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
109 hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
110 TFRC_OPSYS_HALF_TIME_GRAN);
112 ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n",
113 hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta,
114 hctx->ccid3hctx_s, (unsigned)(hctx->ccid3hctx_x >> 6));
120 * X_calc = calcX(s, R, p);
121 * X = max(min(X_calc, 2 * X_recv), s / t_mbi);
123 * If (now - tld >= R)
124 * X = max(min(2 * X, 2 * X_recv), s / R);
127 * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
128 * fine-grained resolution of sending rates. This requires scaling by 2^6
129 * throughout the code. Only X_calc is unscaled (in bytes/second).
132 static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
135 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
136 const __u64 old_x = hctx->ccid3hctx_x;
138 if (hctx->ccid3hctx_p > 0) {
140 hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
141 hctx->ccid3hctx_x_recv * 2);
142 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
143 (((__u64)hctx->ccid3hctx_s) << 6) /
146 } else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) -
147 (suseconds_t)hctx->ccid3hctx_rtt >= 0) {
150 max(2 * min(hctx->ccid3hctx_x, hctx->ccid3hctx_x_recv),
151 scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
152 hctx->ccid3hctx_rtt));
153 hctx->ccid3hctx_t_ld = *now;
156 if (hctx->ccid3hctx_x != old_x) {
157 ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
158 "X_recv=%u\n", (unsigned)(old_x >> 6),
159 (unsigned)(hctx->ccid3hctx_x >> 6),
160 hctx->ccid3hctx_x_calc,
161 (unsigned)(hctx->ccid3hctx_x_recv >> 6));
163 ccid3_update_send_interval(hctx);
168 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
169 * @len: DCCP packet payload size in bytes
171 static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
173 const u16 old_s = hctx->ccid3hctx_s;
175 hctx->ccid3hctx_s = old_s == 0 ? len : (9 * old_s + len) / 10;
177 if (hctx->ccid3hctx_s != old_s)
178 ccid3_update_send_interval(hctx);
182 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
183 * The algorithm is not applicable if RTT < 4 microseconds.
185 static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
191 if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */
194 delta = timeval_delta(now, &hctx->ccid3hctx_t_last_win_count);
195 DCCP_BUG_ON(delta < 0);
197 quarter_rtts = (u32)delta / (hctx->ccid3hctx_rtt / 4);
199 if (quarter_rtts > 0) {
200 hctx->ccid3hctx_t_last_win_count = *now;
201 hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5);
202 hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
204 ccid3_pr_debug("now at %#X\n", hctx->ccid3hctx_last_win_count);
208 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
210 struct sock *sk = (struct sock *)data;
211 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
212 unsigned long t_nfb = USEC_PER_SEC / 5;
215 if (sock_owned_by_user(sk)) {
216 /* Try again later. */
217 /* XXX: set some sensible MIB */
221 ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
222 ccid3_tx_state_name(hctx->ccid3hctx_state));
224 switch (hctx->ccid3hctx_state) {
225 case TFRC_SSTATE_NO_FBACK:
226 /* RFC 3448, 4.4: Halve send rate directly */
227 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
228 (((__u64)hctx->ccid3hctx_s) << 6) /
231 ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u "
232 "bytes/s\n", dccp_role(sk), sk,
233 ccid3_tx_state_name(hctx->ccid3hctx_state),
234 (unsigned)(hctx->ccid3hctx_x >> 6));
235 /* The value of R is still undefined and so we can not recompute
236 * the timout value. Keep initial value as per [RFC 4342, 5]. */
237 t_nfb = TFRC_INITIAL_TIMEOUT;
238 ccid3_update_send_interval(hctx);
240 case TFRC_SSTATE_FBACK:
242 * Check if IDLE since last timeout and recv rate is less than
243 * 4 packets (in units of 64*bytes/sec) per RTT
245 if (!hctx->ccid3hctx_idle ||
246 (hctx->ccid3hctx_x_recv >= 4 *
247 scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
248 hctx->ccid3hctx_rtt))) {
251 ccid3_pr_debug("%s(%p, state=%s), not idle\n",
253 ccid3_tx_state_name(hctx->ccid3hctx_state));
256 * Modify the cached value of X_recv [RFC 3448, 4.4]
258 * If (p == 0 || X_calc > 2 * X_recv)
259 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
261 * X_recv = X_calc / 4;
263 * Note that X_recv is scaled by 2^6 while X_calc is not
265 BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
267 if (hctx->ccid3hctx_p == 0 ||
268 (hctx->ccid3hctx_x_calc >
269 (hctx->ccid3hctx_x_recv >> 5))) {
271 hctx->ccid3hctx_x_recv =
272 max(hctx->ccid3hctx_x_recv / 2,
273 (((__u64)hctx->ccid3hctx_s) << 6) /
276 if (hctx->ccid3hctx_p == 0)
277 dccp_timestamp(sk, &now);
279 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
280 hctx->ccid3hctx_x_recv <<= 4;
282 /* Now recalculate X [RFC 3448, 4.3, step (4)] */
283 ccid3_hc_tx_update_x(sk, &now);
286 * Schedule no feedback timer to expire in
287 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
288 * See comments in packet_recv() regarding the value of t_RTO.
290 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
292 case TFRC_SSTATE_NO_SENT:
293 DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk);
295 case TFRC_SSTATE_TERM:
299 hctx->ccid3hctx_idle = 1;
302 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
303 jiffies + usecs_to_jiffies(t_nfb));
311 * > 0: delay (in msecs) that should pass before actually sending
312 * = 0: can send immediately
313 * < 0: error condition; do not send packet
315 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
317 struct dccp_sock *dp = dccp_sk(sk);
318 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
322 BUG_ON(hctx == NULL);
325 * This function is called only for Data and DataAck packets. Sending
326 * zero-sized Data(Ack)s is theoretically possible, but for congestion
327 * control this case is pathological - ignore it.
329 if (unlikely(skb->len == 0))
332 dccp_timestamp(sk, &now);
334 switch (hctx->ccid3hctx_state) {
335 case TFRC_SSTATE_NO_SENT:
336 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
338 usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
339 hctx->ccid3hctx_last_win_count = 0;
340 hctx->ccid3hctx_t_last_win_count = now;
341 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
343 /* Set initial sending rate X/s to 1pps (X is scaled by 2^6) */
344 hctx->ccid3hctx_x = hctx->ccid3hctx_s = skb->len;
345 hctx->ccid3hctx_x <<= 6;
347 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
348 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
349 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
350 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
352 /* Set t_0 for initial packet */
353 hctx->ccid3hctx_t_nom = now;
355 case TFRC_SSTATE_NO_FBACK:
356 case TFRC_SSTATE_FBACK:
357 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
358 ccid3_pr_debug("delay=%ld\n", (long)delay);
360 * Scheduling of packet transmissions [RFC 3448, 4.6]
362 * if (t_now > t_nom - delta)
363 * // send the packet now
365 * // send the packet in (t_nom - t_now) milliseconds.
367 if (delay - (suseconds_t)hctx->ccid3hctx_delta >= 0)
368 return delay / 1000L;
370 ccid3_hc_tx_update_win_count(hctx, &now);
372 case TFRC_SSTATE_TERM:
373 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
377 /* prepare to send now (add options etc.) */
378 dp->dccps_hc_tx_insert_options = 1;
379 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
381 /* set the nominal send time for the next following packet */
382 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
387 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
390 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
392 struct dccp_tx_hist_entry *packet;
394 BUG_ON(hctx == NULL);
396 ccid3_hc_tx_update_s(hctx, len);
398 packet = dccp_tx_hist_entry_new(ccid3_tx_hist, GFP_ATOMIC);
399 if (unlikely(packet == NULL)) {
400 DCCP_CRIT("packet history - out of memory!");
403 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
405 dccp_timestamp(sk, &now);
406 packet->dccphtx_tstamp = now;
407 packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
408 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
409 packet->dccphtx_sent = 1;
410 hctx->ccid3hctx_idle = 0;
413 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
415 const struct dccp_sock *dp = dccp_sk(sk);
416 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
417 struct ccid3_options_received *opt_recv;
418 struct dccp_tx_hist_entry *packet;
422 suseconds_t r_sample, t_elapsed;
424 BUG_ON(hctx == NULL);
426 /* we are only interested in ACKs */
427 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
428 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
431 opt_recv = &hctx->ccid3hctx_options_received;
433 switch (hctx->ccid3hctx_state) {
434 case TFRC_SSTATE_NO_FBACK:
435 case TFRC_SSTATE_FBACK:
436 /* get packet from history to look up t_recvdata */
437 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
438 DCCP_SKB_CB(skb)->dccpd_ack_seq);
439 if (unlikely(packet == NULL)) {
440 DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
441 "in history!\n", dccp_role(sk), sk,
442 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
443 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
447 /* Update receive rate in units of 64 * bytes/second */
448 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
449 hctx->ccid3hctx_x_recv <<= 6;
451 /* Update loss event rate */
452 pinv = opt_recv->ccid3or_loss_event_rate;
453 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
454 hctx->ccid3hctx_p = 0;
455 else /* can not exceed 100% */
456 hctx->ccid3hctx_p = 1000000 / pinv;
458 dccp_timestamp(sk, &now);
461 * Calculate new round trip sample as per [RFC 3448, 4.3] by
462 * R_sample = (now - t_recvdata) - t_elapsed
464 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
465 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
467 DCCP_BUG_ON(r_sample < 0);
468 if (unlikely(r_sample <= t_elapsed))
469 DCCP_WARN("WARNING: r_sample=%dus <= t_elapsed=%dus\n",
470 (int)r_sample, (int)t_elapsed);
472 r_sample -= t_elapsed;
473 CCID3_RTT_SANITY_CHECK(r_sample);
475 /* Update RTT estimate by
476 * If (No feedback recv)
479 * R = q * R + (1 - q) * R_sample;
481 * q is a constant, RFC 3448 recomments 0.9
483 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
485 * Larger Initial Windows [RFC 4342, sec. 5]
487 hctx->ccid3hctx_rtt = r_sample;
488 hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
489 hctx->ccid3hctx_t_ld = now;
491 ccid3_update_send_interval(hctx);
493 ccid3_pr_debug("%s(%p), s=%u, MSS=%u, "
494 "R_sample=%dus, X=%u\n", dccp_role(sk),
495 sk, hctx->ccid3hctx_s,
496 dp->dccps_mss_cache, (int)r_sample,
497 (unsigned)(hctx->ccid3hctx_x >> 6));
499 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
501 hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
504 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
505 if (hctx->ccid3hctx_p > 0)
506 hctx->ccid3hctx_x_calc =
507 tfrc_calc_x(hctx->ccid3hctx_s,
510 ccid3_hc_tx_update_x(sk, &now);
512 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%dus), s=%u, "
513 "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
515 sk, hctx->ccid3hctx_rtt, (int)r_sample,
516 hctx->ccid3hctx_s, hctx->ccid3hctx_p,
517 hctx->ccid3hctx_x_calc,
518 (unsigned)(hctx->ccid3hctx_x_recv >> 6),
519 (unsigned)(hctx->ccid3hctx_x >> 6));
522 /* unschedule no feedback timer */
523 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
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
530 * that we now can send a packet, so wake up dccp_wait_for_ccid
532 sk->sk_write_space(sk);
535 * Update timeout interval for the nofeedback timer.
536 * We use a configuration option to increase the lower bound.
537 * This can help avoid triggering the nofeedback timer too
538 * often ('spinning') on LANs with small RTTs.
540 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
541 CONFIG_IP_DCCP_CCID3_RTO *
542 (USEC_PER_SEC/1000));
544 * Schedule no feedback timer to expire in
545 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
547 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
549 ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
550 "expire in %lu jiffies (%luus)\n",
552 sk, usecs_to_jiffies(t_nfb), t_nfb);
554 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
555 jiffies + usecs_to_jiffies(t_nfb));
558 hctx->ccid3hctx_idle = 1;
560 case TFRC_SSTATE_NO_SENT: /* fall through */
561 case TFRC_SSTATE_TERM: /* ignore feedback when closing */
566 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
567 unsigned char len, u16 idx,
568 unsigned char *value)
571 const struct dccp_sock *dp = dccp_sk(sk);
572 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
573 struct ccid3_options_received *opt_recv;
575 BUG_ON(hctx == NULL);
577 opt_recv = &hctx->ccid3hctx_options_received;
579 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
580 opt_recv->ccid3or_seqno = dp->dccps_gsr;
581 opt_recv->ccid3or_loss_event_rate = ~0;
582 opt_recv->ccid3or_loss_intervals_idx = 0;
583 opt_recv->ccid3or_loss_intervals_len = 0;
584 opt_recv->ccid3or_receive_rate = 0;
588 case TFRC_OPT_LOSS_EVENT_RATE:
589 if (unlikely(len != 4)) {
590 DCCP_WARN("%s(%p), invalid len %d "
591 "for TFRC_OPT_LOSS_EVENT_RATE\n",
592 dccp_role(sk), sk, len);
595 opt_recv->ccid3or_loss_event_rate =
596 ntohl(*(__be32 *)value);
597 ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
599 opt_recv->ccid3or_loss_event_rate);
602 case TFRC_OPT_LOSS_INTERVALS:
603 opt_recv->ccid3or_loss_intervals_idx = idx;
604 opt_recv->ccid3or_loss_intervals_len = len;
605 ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
607 opt_recv->ccid3or_loss_intervals_idx,
608 opt_recv->ccid3or_loss_intervals_len);
610 case TFRC_OPT_RECEIVE_RATE:
611 if (unlikely(len != 4)) {
612 DCCP_WARN("%s(%p), invalid len %d "
613 "for TFRC_OPT_RECEIVE_RATE\n",
614 dccp_role(sk), sk, len);
617 opt_recv->ccid3or_receive_rate =
618 ntohl(*(__be32 *)value);
619 ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
621 opt_recv->ccid3or_receive_rate);
629 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
631 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
633 hctx->ccid3hctx_s = 0;
634 hctx->ccid3hctx_rtt = 0;
635 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
636 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
638 hctx->ccid3hctx_no_feedback_timer.function =
639 ccid3_hc_tx_no_feedback_timer;
640 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
641 init_timer(&hctx->ccid3hctx_no_feedback_timer);
646 static void ccid3_hc_tx_exit(struct sock *sk)
648 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
650 BUG_ON(hctx == NULL);
652 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
653 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
655 /* Empty packet history */
656 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
659 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
661 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
663 /* Listen socks doesn't have a private CCID block */
664 if (sk->sk_state == DCCP_LISTEN)
667 BUG_ON(hctx == NULL);
669 info->tcpi_rto = hctx->ccid3hctx_t_rto;
670 info->tcpi_rtt = hctx->ccid3hctx_rtt;
673 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
674 u32 __user *optval, int __user *optlen)
676 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
679 /* Listen socks doesn't have a private CCID block */
680 if (sk->sk_state == DCCP_LISTEN)
684 case DCCP_SOCKOPT_CCID_TX_INFO:
685 if (len < sizeof(hctx->ccid3hctx_tfrc))
687 len = sizeof(hctx->ccid3hctx_tfrc);
688 val = &hctx->ccid3hctx_tfrc;
694 if (put_user(len, optlen) || copy_to_user(optval, val, len))
701 * Receiver Half-Connection Routines
703 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
704 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
706 static char *ccid3_rx_state_names[] = {
707 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
708 [TFRC_RSTATE_DATA] = "DATA",
709 [TFRC_RSTATE_TERM] = "TERM",
712 return ccid3_rx_state_names[state];
716 static void ccid3_hc_rx_set_state(struct sock *sk,
717 enum ccid3_hc_rx_states state)
719 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
720 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
722 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
723 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
724 ccid3_rx_state_name(state));
725 WARN_ON(state == oldstate);
726 hcrx->ccid3hcrx_state = state;
729 static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
731 if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
732 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
734 hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
735 (9 * hcrx->ccid3hcrx_s + len) / 10;
738 static void ccid3_hc_rx_send_feedback(struct sock *sk)
740 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
741 struct dccp_sock *dp = dccp_sk(sk);
742 struct dccp_rx_hist_entry *packet;
746 ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk);
748 dccp_timestamp(sk, &now);
750 switch (hcrx->ccid3hcrx_state) {
751 case TFRC_RSTATE_NO_DATA:
752 hcrx->ccid3hcrx_x_recv = 0;
754 case TFRC_RSTATE_DATA:
755 delta = timeval_delta(&now,
756 &hcrx->ccid3hcrx_tstamp_last_feedback);
757 DCCP_BUG_ON(delta < 0);
758 hcrx->ccid3hcrx_x_recv =
759 scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
761 case TFRC_RSTATE_TERM:
762 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
766 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
767 if (unlikely(packet == NULL)) {
768 DCCP_WARN("%s(%p), no data packet in history!\n",
773 hcrx->ccid3hcrx_tstamp_last_feedback = now;
774 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
775 hcrx->ccid3hcrx_bytes_recv = 0;
777 /* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
778 delta = timeval_delta(&now, &packet->dccphrx_tstamp);
779 DCCP_BUG_ON(delta < 0);
780 hcrx->ccid3hcrx_elapsed_time = delta / 10;
782 if (hcrx->ccid3hcrx_p == 0)
783 hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
784 else if (hcrx->ccid3hcrx_p > 1000000) {
785 DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
786 hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
788 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
790 dp->dccps_hc_rx_insert_options = 1;
794 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
796 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
799 BUG_ON(hcrx == NULL);
801 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
804 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
806 if (dccp_packet_without_ack(skb))
809 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
810 pinv = htonl(hcrx->ccid3hcrx_pinv);
812 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
813 dccp_insert_option_elapsed_time(sk, skb,
814 hcrx->ccid3hcrx_elapsed_time)) ||
815 dccp_insert_option_timestamp(sk, skb) ||
816 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
817 &pinv, sizeof(pinv)) ||
818 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
819 &x_recv, sizeof(x_recv)))
825 /* calculate first loss interval
827 * returns estimated loss interval in usecs */
829 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
831 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
832 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
834 suseconds_t rtt, delta;
835 struct timeval tstamp = { 0, };
841 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
843 if (dccp_rx_hist_entry_data_packet(entry)) {
848 tstamp = entry->dccphrx_tstamp;
849 win_count = entry->dccphrx_ccval;
853 interval = win_count - entry->dccphrx_ccval;
855 interval += TFRC_WIN_COUNT_LIMIT;
863 if (unlikely(step == 0)) {
864 DCCP_WARN("%s(%p), packet history has no data packets!\n",
869 if (unlikely(interval == 0)) {
870 DCCP_WARN("%s(%p), Could not find a win_count interval > 0."
871 "Defaulting to 1\n", dccp_role(sk), sk);
876 DCCP_CRIT("tail is null\n");
880 delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
881 DCCP_BUG_ON(delta < 0);
883 rtt = delta * 4 / interval;
884 ccid3_pr_debug("%s(%p), approximated RTT to %dus\n",
885 dccp_role(sk), sk, (int)rtt);
888 * Determine the length of the first loss interval via inverse lookup.
889 * Assume that X_recv can be computed by the throughput equation
893 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
895 if (rtt == 0) { /* would result in divide-by-zero */
896 DCCP_WARN("RTT==0\n");
900 dccp_timestamp(sk, &tstamp);
901 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
902 DCCP_BUG_ON(delta <= 0);
904 x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
905 if (x_recv == 0) { /* would also trigger divide-by-zero */
906 DCCP_WARN("X_recv==0\n");
907 if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
908 DCCP_BUG("stored value of X_recv is zero");
913 fval = scaled_div(hcrx->ccid3hcrx_s, rtt);
914 fval = scaled_div32(fval, x_recv);
915 p = tfrc_calc_x_reverse_lookup(fval);
917 ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
918 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
926 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
928 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
929 struct dccp_li_hist_entry *head;
932 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
933 if (!dccp_li_hist_interval_new(ccid3_li_hist,
934 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
937 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
938 struct dccp_li_hist_entry, dccplih_node);
939 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
941 struct dccp_li_hist_entry *entry;
942 struct list_head *tail;
944 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
945 struct dccp_li_hist_entry, dccplih_node);
946 /* FIXME win count check removed as was wrong */
947 /* should make this check with receive history */
948 /* and compare there as per section 10.2 of RFC4342 */
950 /* new loss event detected */
951 /* calculate last interval length */
952 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
953 entry = dccp_li_hist_entry_new(ccid3_li_hist, GFP_ATOMIC);
956 DCCP_BUG("out of memory - can not allocate entry");
960 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
962 tail = hcrx->ccid3hcrx_li_hist.prev;
964 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
966 /* Create the newest interval */
967 entry->dccplih_seqno = seq_loss;
968 entry->dccplih_interval = seq_temp;
969 entry->dccplih_win_count = win_loss;
973 static int ccid3_hc_rx_detect_loss(struct sock *sk,
974 struct dccp_rx_hist_entry *packet)
976 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
977 struct dccp_rx_hist_entry *rx_hist =
978 dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
979 u64 seqno = packet->dccphrx_seqno;
985 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
988 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
989 hcrx->ccid3hcrx_seqno_nonloss = seqno;
990 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
995 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
996 > TFRC_RECV_NUM_LATE_LOSS) {
998 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
999 hcrx->ccid3hcrx_ccval_nonloss);
1000 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
1001 dccp_inc_seqno(&tmp_seqno);
1002 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
1003 dccp_inc_seqno(&tmp_seqno);
1004 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
1005 tmp_seqno, &ccval)) {
1006 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
1007 hcrx->ccid3hcrx_ccval_nonloss = ccval;
1008 dccp_inc_seqno(&tmp_seqno);
1012 /* FIXME - this code could be simplified with above while */
1013 /* but works at moment */
1014 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
1015 hcrx->ccid3hcrx_seqno_nonloss = seqno;
1016 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
1020 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
1021 &hcrx->ccid3hcrx_li_hist, packet,
1022 hcrx->ccid3hcrx_seqno_nonloss);
1026 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
1028 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1029 const struct dccp_options_received *opt_recv;
1030 struct dccp_rx_hist_entry *packet;
1032 u32 p_prev, rtt_prev;
1033 suseconds_t r_sample, t_elapsed;
1034 int loss, payload_size;
1036 BUG_ON(hcrx == NULL);
1038 opt_recv = &dccp_sk(sk)->dccps_options_received;
1040 switch (DCCP_SKB_CB(skb)->dccpd_type) {
1042 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1044 case DCCP_PKT_DATAACK:
1045 if (opt_recv->dccpor_timestamp_echo == 0)
1047 rtt_prev = hcrx->ccid3hcrx_rtt;
1048 dccp_timestamp(sk, &now);
1049 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
1050 r_sample = timeval_usecs(&now);
1051 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
1053 DCCP_BUG_ON(r_sample < 0);
1054 if (unlikely(r_sample <= t_elapsed))
1055 DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
1056 (long)r_sample, (long)t_elapsed);
1058 r_sample -= t_elapsed;
1059 CCID3_RTT_SANITY_CHECK(r_sample);
1061 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1062 hcrx->ccid3hcrx_rtt = r_sample;
1064 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
1067 if (rtt_prev != hcrx->ccid3hcrx_rtt)
1068 ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n",
1069 dccp_role(sk), sk, hcrx->ccid3hcrx_rtt,
1070 opt_recv->dccpor_elapsed_time);
1074 default: /* We're not interested in other packet types, move along */
1078 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
1080 if (unlikely(packet == NULL)) {
1081 DCCP_WARN("%s(%p), Not enough mem to add rx packet "
1082 "to history, consider it lost!\n", dccp_role(sk), sk);
1086 loss = ccid3_hc_rx_detect_loss(sk, packet);
1088 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1091 payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
1092 ccid3_hc_rx_update_s(hcrx, payload_size);
1094 switch (hcrx->ccid3hcrx_state) {
1095 case TFRC_RSTATE_NO_DATA:
1096 ccid3_pr_debug("%s(%p, state=%s), skb=%p, sending initial "
1097 "feedback\n", dccp_role(sk), sk,
1098 dccp_state_name(sk->sk_state), skb);
1099 ccid3_hc_rx_send_feedback(sk);
1100 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1102 case TFRC_RSTATE_DATA:
1103 hcrx->ccid3hcrx_bytes_recv += payload_size;
1107 dccp_timestamp(sk, &now);
1108 if ((timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
1109 (suseconds_t)hcrx->ccid3hcrx_rtt) >= 0) {
1110 hcrx->ccid3hcrx_tstamp_last_ack = now;
1111 ccid3_hc_rx_send_feedback(sk);
1114 case TFRC_RSTATE_TERM:
1115 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
1119 /* Dealing with packet loss */
1120 ccid3_pr_debug("%s(%p, state=%s), data loss! Reacting...\n",
1121 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1123 p_prev = hcrx->ccid3hcrx_p;
1125 /* Calculate loss event rate */
1126 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1127 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1129 /* Scaling up by 1000000 as fixed decimal */
1131 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1133 DCCP_BUG("empty loss history");
1135 if (hcrx->ccid3hcrx_p > p_prev) {
1136 ccid3_hc_rx_send_feedback(sk);
1141 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1143 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1145 ccid3_pr_debug("entry\n");
1147 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1148 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1149 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1150 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1151 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1152 hcrx->ccid3hcrx_s = 0;
1153 hcrx->ccid3hcrx_rtt = 0;
1157 static void ccid3_hc_rx_exit(struct sock *sk)
1159 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1161 BUG_ON(hcrx == NULL);
1163 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1165 /* Empty packet history */
1166 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1168 /* Empty loss interval history */
1169 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1172 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1174 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1176 /* Listen socks doesn't have a private CCID block */
1177 if (sk->sk_state == DCCP_LISTEN)
1180 BUG_ON(hcrx == NULL);
1182 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1183 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1184 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1187 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1188 u32 __user *optval, int __user *optlen)
1190 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1193 /* Listen socks doesn't have a private CCID block */
1194 if (sk->sk_state == DCCP_LISTEN)
1198 case DCCP_SOCKOPT_CCID_RX_INFO:
1199 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1201 len = sizeof(hcrx->ccid3hcrx_tfrc);
1202 val = &hcrx->ccid3hcrx_tfrc;
1205 return -ENOPROTOOPT;
1208 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1214 static struct ccid_operations ccid3 = {
1215 .ccid_id = DCCPC_CCID3,
1216 .ccid_name = "ccid3",
1217 .ccid_owner = THIS_MODULE,
1218 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1219 .ccid_hc_tx_init = ccid3_hc_tx_init,
1220 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1221 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1222 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1223 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1224 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1225 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1226 .ccid_hc_rx_init = ccid3_hc_rx_init,
1227 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1228 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1229 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1230 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1231 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1232 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1233 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1236 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1237 module_param(ccid3_debug, int, 0444);
1238 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1241 static __init int ccid3_module_init(void)
1245 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1246 if (ccid3_rx_hist == NULL)
1249 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1250 if (ccid3_tx_hist == NULL)
1253 ccid3_li_hist = dccp_li_hist_new("ccid3");
1254 if (ccid3_li_hist == NULL)
1257 rc = ccid_register(&ccid3);
1259 goto out_free_loss_interval_history;
1263 out_free_loss_interval_history:
1264 dccp_li_hist_delete(ccid3_li_hist);
1265 ccid3_li_hist = NULL;
1267 dccp_tx_hist_delete(ccid3_tx_hist);
1268 ccid3_tx_hist = NULL;
1270 dccp_rx_hist_delete(ccid3_rx_hist);
1271 ccid3_rx_hist = NULL;
1274 module_init(ccid3_module_init);
1276 static __exit void ccid3_module_exit(void)
1278 ccid_unregister(&ccid3);
1280 if (ccid3_tx_hist != NULL) {
1281 dccp_tx_hist_delete(ccid3_tx_hist);
1282 ccid3_tx_hist = NULL;
1284 if (ccid3_rx_hist != NULL) {
1285 dccp_rx_hist_delete(ccid3_rx_hist);
1286 ccid3_rx_hist = NULL;
1288 if (ccid3_li_hist != NULL) {
1289 dccp_li_hist_delete(ccid3_li_hist);
1290 ccid3_li_hist = NULL;
1293 module_exit(ccid3_module_exit);
1295 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1296 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1297 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1298 MODULE_LICENSE("GPL");
1299 MODULE_ALIAS("net-dccp-ccid-3");