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"
44 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
45 static int ccid3_debug;
46 #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
48 #define ccid3_pr_debug(format, a...)
51 static struct dccp_tx_hist *ccid3_tx_hist;
52 static struct dccp_rx_hist *ccid3_rx_hist;
53 static struct dccp_li_hist *ccid3_li_hist;
55 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
56 static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
58 static char *ccid3_state_names[] = {
59 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
60 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
61 [TFRC_SSTATE_FBACK] = "FBACK",
62 [TFRC_SSTATE_TERM] = "TERM",
65 return ccid3_state_names[state];
69 static void ccid3_hc_tx_set_state(struct sock *sk,
70 enum ccid3_hc_tx_states state)
72 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
73 enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
75 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
76 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
77 ccid3_tx_state_name(state));
78 WARN_ON(state == oldstate);
79 hctx->ccid3hctx_state = state;
83 * Recalculate scheduled nominal send time t_nom, inter-packet interval
84 * t_ipi, and delta value. Should be called after each change to X.
86 static inline void ccid3_update_send_time(struct ccid3_hc_tx_sock *hctx)
88 timeval_sub_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
90 /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
91 hctx->ccid3hctx_t_ipi = scaled_div(hctx->ccid3hctx_s,
92 hctx->ccid3hctx_x >> 6);
94 /* Update nominal send time with regard to the new t_ipi */
95 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
97 /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
98 hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
99 TFRC_OPSYS_HALF_TIME_GRAN);
104 * X_calc = calcX(s, R, p);
105 * X = max(min(X_calc, 2 * X_recv), s / t_mbi);
107 * If (now - tld >= R)
108 * X = max(min(2 * X, 2 * X_recv), s / R);
111 * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
112 * fine-grained resolution of sending rates. This requires scaling by 2^6
113 * throughout the code. Only X_calc is unscaled (in bytes/second).
115 * If X has changed, we also update the scheduled send time t_now,
116 * the inter-packet interval t_ipi, and the delta value.
118 static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
121 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
122 const __u64 old_x = hctx->ccid3hctx_x;
124 if (hctx->ccid3hctx_p > 0) {
126 hctx->ccid3hctx_x = min_t(u64, hctx->ccid3hctx_x_calc << 6,
127 hctx->ccid3hctx_x_recv * 2 );
128 hctx->ccid3hctx_x = max_t(u64, hctx->ccid3hctx_x,
129 (hctx->ccid3hctx_s << 6)/TFRC_T_MBI);
131 } else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) -
132 (suseconds_t)hctx->ccid3hctx_rtt >= 0 ) {
134 hctx->ccid3hctx_x = max(2 * min(hctx->ccid3hctx_x,
135 hctx->ccid3hctx_x_recv),
136 scaled_div(hctx->ccid3hctx_s << 6,
137 hctx->ccid3hctx_rtt ));
138 hctx->ccid3hctx_t_ld = *now;
141 if (hctx->ccid3hctx_x != old_x)
142 ccid3_update_send_time(hctx);
146 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
147 * @len: DCCP packet payload size in bytes
149 static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
151 if (unlikely(len == 0))
152 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
154 hctx->ccid3hctx_s = hctx->ccid3hctx_s == 0 ? len :
155 (9 * hctx->ccid3hctx_s + len) / 10;
157 * Note: We could do a potential optimisation here - when `s' changes,
158 * recalculate sending rate and consequently t_ipi, t_delta, and
159 * t_now. This is however non-standard, and the benefits are not
160 * clear, so it is currently left out.
164 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
166 struct sock *sk = (struct sock *)data;
167 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
168 unsigned long t_nfb = USEC_PER_SEC / 5;
171 if (sock_owned_by_user(sk)) {
172 /* Try again later. */
173 /* XXX: set some sensible MIB */
177 ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
178 ccid3_tx_state_name(hctx->ccid3hctx_state));
180 switch (hctx->ccid3hctx_state) {
181 case TFRC_SSTATE_NO_FBACK:
182 /* RFC 3448, 4.4: Halve send rate directly */
183 hctx->ccid3hctx_x = max_t(u32, hctx->ccid3hctx_x / 2,
184 (hctx->ccid3hctx_s << 6)/TFRC_T_MBI);
186 ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %u "
189 ccid3_tx_state_name(hctx->ccid3hctx_state),
190 (unsigned)(hctx->ccid3hctx_x >> 6));
191 /* The value of R is still undefined and so we can not recompute
192 * the timout value. Keep initial value as per [RFC 4342, 5]. */
193 t_nfb = TFRC_INITIAL_TIMEOUT;
194 ccid3_update_send_time(hctx);
196 case TFRC_SSTATE_FBACK:
198 * Check if IDLE since last timeout and recv rate is less than
199 * 4 packets (in units of 64*bytes/sec) per RTT
201 if (!hctx->ccid3hctx_idle ||
202 (hctx->ccid3hctx_x_recv >= 4 *
203 scaled_div(hctx->ccid3hctx_s << 6, hctx->ccid3hctx_rtt))) {
206 ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
208 ccid3_tx_state_name(hctx->ccid3hctx_state));
211 * Modify the cached value of X_recv [RFC 3448, 4.4]
213 * If (p == 0 || X_calc > 2 * X_recv)
214 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
216 * X_recv = X_calc / 4;
218 * Note that X_recv is scaled by 2^6 while X_calc is not
220 BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
222 if (hctx->ccid3hctx_p == 0 ||
223 hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5)) {
225 hctx->ccid3hctx_x_recv =
226 max_t(u64, hctx->ccid3hctx_x_recv / 2,
227 (hctx->ccid3hctx_s << 6) /
230 if (hctx->ccid3hctx_p == 0)
231 dccp_timestamp(sk, &now);
233 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc << 4;
235 /* Now recalculate X [RFC 3448, 4.3, step (4)] */
236 ccid3_hc_tx_update_x(sk, &now);
239 * Schedule no feedback timer to expire in
240 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
241 * See comments in packet_recv() regarding the value of t_RTO.
243 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
245 case TFRC_SSTATE_NO_SENT:
246 DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
248 case TFRC_SSTATE_TERM:
252 hctx->ccid3hctx_idle = 1;
255 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
256 jiffies + usecs_to_jiffies(t_nfb));
264 * > 0: delay (in msecs) that should pass before actually sending
265 * = 0: can send immediately
266 * < 0: error condition; do not send packet
268 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
270 struct dccp_sock *dp = dccp_sk(sk);
271 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
272 struct dccp_tx_hist_entry *new_packet;
276 BUG_ON(hctx == NULL);
279 * This function is called only for Data and DataAck packets. Sending
280 * zero-sized Data(Ack)s is theoretically possible, but for congestion
281 * control this case is pathological - ignore it.
283 if (unlikely(skb->len == 0))
286 /* See if last packet allocated was not sent */
287 new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
288 if (new_packet == NULL || new_packet->dccphtx_sent) {
289 new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
292 if (unlikely(new_packet == NULL)) {
293 DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
294 "send refused\n", dccp_role(sk), sk);
298 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
301 dccp_timestamp(sk, &now);
303 switch (hctx->ccid3hctx_state) {
304 case TFRC_SSTATE_NO_SENT:
305 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
306 jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
307 hctx->ccid3hctx_last_win_count = 0;
308 hctx->ccid3hctx_t_last_win_count = now;
309 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
311 /* Set initial sending rate X/s to 1pps (X is scaled by 2^6) */
312 ccid3_hc_tx_update_s(hctx, skb->len);
313 hctx->ccid3hctx_x = hctx->ccid3hctx_s << 6;
315 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
316 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
317 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
318 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
320 /* Set t_0 for initial packet */
321 hctx->ccid3hctx_t_nom = now;
323 case TFRC_SSTATE_NO_FBACK:
324 case TFRC_SSTATE_FBACK:
325 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
327 * Scheduling of packet transmissions [RFC 3448, 4.6]
329 * if (t_now > t_nom - delta)
330 * // send the packet now
332 * // send the packet in (t_nom - t_now) milliseconds.
334 if (delay - (suseconds_t)hctx->ccid3hctx_delta >= 0)
335 return delay / 1000L;
337 case TFRC_SSTATE_TERM:
338 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
342 /* prepare to send now (add options etc.) */
343 dp->dccps_hc_tx_insert_options = 1;
344 new_packet->dccphtx_ccval = DCCP_SKB_CB(skb)->dccpd_ccval =
345 hctx->ccid3hctx_last_win_count;
346 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
351 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
353 const struct dccp_sock *dp = dccp_sk(sk);
354 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
356 suseconds_t quarter_rtt;
357 struct dccp_tx_hist_entry *packet;
359 BUG_ON(hctx == NULL);
361 dccp_timestamp(sk, &now);
363 ccid3_hc_tx_update_s(hctx, len);
365 packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
366 if (unlikely(packet == NULL)) {
367 DCCP_WARN("packet doesn't exist in history!\n");
370 if (unlikely(packet->dccphtx_sent)) {
371 DCCP_WARN("no unsent packet in history!\n");
374 packet->dccphtx_tstamp = now;
375 packet->dccphtx_seqno = dp->dccps_gss;
377 * Check if win_count have changed
378 * Algorithm in "8.1. Window Counter Value" in RFC 4342.
380 quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
381 if (likely(hctx->ccid3hctx_rtt > 8))
382 quarter_rtt /= hctx->ccid3hctx_rtt / 4;
384 if (quarter_rtt > 0) {
385 hctx->ccid3hctx_t_last_win_count = now;
386 hctx->ccid3hctx_last_win_count = (hctx->ccid3hctx_last_win_count +
387 min_t(unsigned long, quarter_rtt, 5)) % 16;
388 ccid3_pr_debug("%s, sk=%p, window changed from "
391 packet->dccphtx_ccval,
392 hctx->ccid3hctx_last_win_count);
395 hctx->ccid3hctx_idle = 0;
396 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
397 packet->dccphtx_sent = 1;
400 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
402 const struct dccp_sock *dp = dccp_sk(sk);
403 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
404 struct ccid3_options_received *opt_recv;
405 struct dccp_tx_hist_entry *packet;
409 long r_sample, t_elapsed;
411 BUG_ON(hctx == NULL);
413 /* we are only interested in ACKs */
414 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
415 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
418 opt_recv = &hctx->ccid3hctx_options_received;
420 switch (hctx->ccid3hctx_state) {
421 case TFRC_SSTATE_NO_FBACK:
422 case TFRC_SSTATE_FBACK:
423 /* get packet from history to look up t_recvdata */
424 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
425 DCCP_SKB_CB(skb)->dccpd_ack_seq);
426 if (unlikely(packet == NULL)) {
427 DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
428 "in history!\n", dccp_role(sk), sk,
429 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
430 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
434 /* Update receive rate in units of 64 * bytes/second */
435 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate << 6;
437 /* Update loss event rate */
438 pinv = opt_recv->ccid3or_loss_event_rate;
439 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
440 hctx->ccid3hctx_p = 0;
441 else /* can not exceed 100% */
442 hctx->ccid3hctx_p = 1000000 / pinv;
444 dccp_timestamp(sk, &now);
447 * Calculate new round trip sample as per [RFC 3448, 4.3] by
448 * R_sample = (now - t_recvdata) - t_elapsed
450 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
451 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
453 DCCP_BUG_ON(r_sample < 0);
454 if (unlikely(r_sample <= t_elapsed))
455 DCCP_WARN("WARNING: r_sample=%ldus <= t_elapsed=%ldus\n",
456 r_sample, t_elapsed);
458 r_sample -= t_elapsed;
459 CCID3_RTT_SANITY_CHECK(r_sample);
461 /* Update RTT estimate by
462 * If (No feedback recv)
465 * R = q * R + (1 - q) * R_sample;
467 * q is a constant, RFC 3448 recomments 0.9
469 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
471 * Larger Initial Windows [RFC 4342, sec. 5]
472 * We deviate in that we use `s' instead of `MSS'.
474 u16 w_init = min( 4 * hctx->ccid3hctx_s,
475 max(2 * hctx->ccid3hctx_s, 4380));
476 hctx->ccid3hctx_rtt = r_sample;
477 hctx->ccid3hctx_x = scaled_div(w_init<< 6, r_sample);
478 hctx->ccid3hctx_t_ld = now;
480 ccid3_update_send_time(hctx);
482 ccid3_pr_debug("%s(%p), s=%u, w_init=%u, "
483 "R_sample=%ldus, X=%u\n", dccp_role(sk),
484 sk, hctx->ccid3hctx_s, w_init, r_sample,
485 (unsigned)(hctx->ccid3hctx_x >> 6));
487 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
489 hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
490 (u32)r_sample ) / 10;
492 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
493 if (hctx->ccid3hctx_p > 0)
494 hctx->ccid3hctx_x_calc =
495 tfrc_calc_x(hctx->ccid3hctx_s,
498 ccid3_hc_tx_update_x(sk, &now);
500 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%ldus), s=%u, "
501 "p=%u, X_calc=%u, X=%u\n", dccp_role(sk),
502 sk, hctx->ccid3hctx_rtt, r_sample,
503 hctx->ccid3hctx_s, hctx->ccid3hctx_p,
504 hctx->ccid3hctx_x_calc,
505 (unsigned)(hctx->ccid3hctx_x >> 6));
508 /* unschedule no feedback timer */
509 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
511 /* remove all packets older than the one acked from history */
512 dccp_tx_hist_purge_older(ccid3_tx_hist,
513 &hctx->ccid3hctx_hist, packet);
515 * As we have calculated new ipi, delta, t_nom it is possible that
516 * we now can send a packet, so wake up dccp_wait_for_ccid
518 sk->sk_write_space(sk);
521 * Update timeout interval for the nofeedback timer.
522 * We use a configuration option to increase the lower bound.
523 * This can help avoid triggering the nofeedback timer too often
524 * ('spinning') on LANs with small RTTs.
526 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
527 CONFIG_IP_DCCP_CCID3_RTO *
528 (USEC_PER_SEC/1000) );
530 * Schedule no feedback timer to expire in
531 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
533 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
535 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
536 "expire in %lu jiffies (%luus)\n",
538 usecs_to_jiffies(t_nfb), t_nfb);
540 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
541 jiffies + usecs_to_jiffies(t_nfb));
544 hctx->ccid3hctx_idle = 1;
546 case TFRC_SSTATE_NO_SENT:
547 /* XXX when implementing bidirectional rx/tx check this again */
548 DCCP_WARN("Illegal ACK received - no packet sent\n");
550 case TFRC_SSTATE_TERM: /* ignore feedback when closing */
555 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
556 unsigned char len, u16 idx,
557 unsigned char *value)
560 const struct dccp_sock *dp = dccp_sk(sk);
561 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
562 struct ccid3_options_received *opt_recv;
564 BUG_ON(hctx == NULL);
566 opt_recv = &hctx->ccid3hctx_options_received;
568 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
569 opt_recv->ccid3or_seqno = dp->dccps_gsr;
570 opt_recv->ccid3or_loss_event_rate = ~0;
571 opt_recv->ccid3or_loss_intervals_idx = 0;
572 opt_recv->ccid3or_loss_intervals_len = 0;
573 opt_recv->ccid3or_receive_rate = 0;
577 case TFRC_OPT_LOSS_EVENT_RATE:
578 if (unlikely(len != 4)) {
579 DCCP_WARN("%s, sk=%p, invalid len %d "
580 "for TFRC_OPT_LOSS_EVENT_RATE\n",
581 dccp_role(sk), sk, len);
584 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
585 ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
587 opt_recv->ccid3or_loss_event_rate);
590 case TFRC_OPT_LOSS_INTERVALS:
591 opt_recv->ccid3or_loss_intervals_idx = idx;
592 opt_recv->ccid3or_loss_intervals_len = len;
593 ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
595 opt_recv->ccid3or_loss_intervals_idx,
596 opt_recv->ccid3or_loss_intervals_len);
598 case TFRC_OPT_RECEIVE_RATE:
599 if (unlikely(len != 4)) {
600 DCCP_WARN("%s, sk=%p, invalid len %d "
601 "for TFRC_OPT_RECEIVE_RATE\n",
602 dccp_role(sk), sk, len);
605 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
606 ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
608 opt_recv->ccid3or_receive_rate);
616 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
618 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
620 hctx->ccid3hctx_s = 0;
621 hctx->ccid3hctx_rtt = 0;
622 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
623 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
625 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
626 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
627 init_timer(&hctx->ccid3hctx_no_feedback_timer);
632 static void ccid3_hc_tx_exit(struct sock *sk)
634 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
636 BUG_ON(hctx == NULL);
638 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
639 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
641 /* Empty packet history */
642 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
646 * RX Half Connection methods
649 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
650 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
652 static char *ccid3_rx_state_names[] = {
653 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
654 [TFRC_RSTATE_DATA] = "DATA",
655 [TFRC_RSTATE_TERM] = "TERM",
658 return ccid3_rx_state_names[state];
662 static void ccid3_hc_rx_set_state(struct sock *sk,
663 enum ccid3_hc_rx_states state)
665 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
666 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
668 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
669 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
670 ccid3_rx_state_name(state));
671 WARN_ON(state == oldstate);
672 hcrx->ccid3hcrx_state = state;
675 static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
677 if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
678 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
680 hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
681 (9 * hcrx->ccid3hcrx_s + len) / 10;
684 static void ccid3_hc_rx_send_feedback(struct sock *sk)
686 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
687 struct dccp_sock *dp = dccp_sk(sk);
688 struct dccp_rx_hist_entry *packet;
692 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
694 dccp_timestamp(sk, &now);
696 switch (hcrx->ccid3hcrx_state) {
697 case TFRC_RSTATE_NO_DATA:
698 hcrx->ccid3hcrx_x_recv = 0;
700 case TFRC_RSTATE_DATA:
701 delta = timeval_delta(&now,
702 &hcrx->ccid3hcrx_tstamp_last_feedback);
703 DCCP_BUG_ON(delta < 0);
704 hcrx->ccid3hcrx_x_recv =
705 scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
707 case TFRC_RSTATE_TERM:
708 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
712 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
713 if (unlikely(packet == NULL)) {
714 DCCP_WARN("%s, sk=%p, no data packet in history!\n",
719 hcrx->ccid3hcrx_tstamp_last_feedback = now;
720 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
721 hcrx->ccid3hcrx_bytes_recv = 0;
723 /* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
724 delta = timeval_delta(&now, &packet->dccphrx_tstamp);
725 DCCP_BUG_ON(delta < 0);
726 hcrx->ccid3hcrx_elapsed_time = delta / 10;
728 if (hcrx->ccid3hcrx_p == 0)
729 hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
730 else if (hcrx->ccid3hcrx_p > 1000000) {
731 DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
732 hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
734 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
736 dp->dccps_hc_rx_insert_options = 1;
740 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
742 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
745 BUG_ON(hcrx == NULL);
747 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
750 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
752 if (dccp_packet_without_ack(skb))
755 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
756 pinv = htonl(hcrx->ccid3hcrx_pinv);
758 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
759 dccp_insert_option_elapsed_time(sk, skb,
760 hcrx->ccid3hcrx_elapsed_time)) ||
761 dccp_insert_option_timestamp(sk, skb) ||
762 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
763 &pinv, sizeof(pinv)) ||
764 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
765 &x_recv, sizeof(x_recv)))
771 /* calculate first loss interval
773 * returns estimated loss interval in usecs */
775 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
777 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
778 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
780 suseconds_t rtt, delta;
781 struct timeval tstamp = { 0, };
787 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
789 if (dccp_rx_hist_entry_data_packet(entry)) {
794 tstamp = entry->dccphrx_tstamp;
795 win_count = entry->dccphrx_ccval;
799 interval = win_count - entry->dccphrx_ccval;
801 interval += TFRC_WIN_COUNT_LIMIT;
809 if (unlikely(step == 0)) {
810 DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
815 if (unlikely(interval == 0)) {
816 DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
817 "Defaulting to 1\n", dccp_role(sk), sk);
822 DCCP_CRIT("tail is null\n");
826 delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
827 DCCP_BUG_ON(delta < 0);
829 rtt = delta * 4 / interval;
830 ccid3_pr_debug("%s, sk=%p, approximated RTT to %ldus\n",
831 dccp_role(sk), sk, rtt);
834 * Determine the length of the first loss interval via inverse lookup.
835 * Assume that X_recv can be computed by the throughput equation
839 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
841 if (rtt == 0) { /* would result in divide-by-zero */
842 DCCP_WARN("RTT==0, returning 1/p = 1\n");
846 dccp_timestamp(sk, &tstamp);
847 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
848 DCCP_BUG_ON(delta <= 0);
850 x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
851 if (x_recv == 0) { /* would also trigger divide-by-zero */
852 DCCP_WARN("X_recv==0\n");
853 if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
854 DCCP_BUG("stored value of X_recv is zero");
859 fval = scaled_div(hcrx->ccid3hcrx_s, rtt);
860 fval = scaled_div32(fval, x_recv);
861 p = tfrc_calc_x_reverse_lookup(fval);
863 ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
864 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
872 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
874 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
875 struct dccp_li_hist_entry *head;
878 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
879 if (!dccp_li_hist_interval_new(ccid3_li_hist,
880 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
883 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
884 struct dccp_li_hist_entry, dccplih_node);
885 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
887 struct dccp_li_hist_entry *entry;
888 struct list_head *tail;
890 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
891 struct dccp_li_hist_entry, dccplih_node);
892 /* FIXME win count check removed as was wrong */
893 /* should make this check with receive history */
894 /* and compare there as per section 10.2 of RFC4342 */
896 /* new loss event detected */
897 /* calculate last interval length */
898 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
899 entry = dccp_li_hist_entry_new(ccid3_li_hist, GFP_ATOMIC);
902 DCCP_BUG("out of memory - can not allocate entry");
906 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
908 tail = hcrx->ccid3hcrx_li_hist.prev;
910 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
912 /* Create the newest interval */
913 entry->dccplih_seqno = seq_loss;
914 entry->dccplih_interval = seq_temp;
915 entry->dccplih_win_count = win_loss;
919 static int ccid3_hc_rx_detect_loss(struct sock *sk,
920 struct dccp_rx_hist_entry *packet)
922 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
923 struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
924 u64 seqno = packet->dccphrx_seqno;
930 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
933 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
934 hcrx->ccid3hcrx_seqno_nonloss = seqno;
935 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
940 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
941 > TFRC_RECV_NUM_LATE_LOSS) {
943 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
944 hcrx->ccid3hcrx_ccval_nonloss);
945 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
946 dccp_inc_seqno(&tmp_seqno);
947 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
948 dccp_inc_seqno(&tmp_seqno);
949 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
950 tmp_seqno, &ccval)) {
951 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
952 hcrx->ccid3hcrx_ccval_nonloss = ccval;
953 dccp_inc_seqno(&tmp_seqno);
957 /* FIXME - this code could be simplified with above while */
958 /* but works at moment */
959 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
960 hcrx->ccid3hcrx_seqno_nonloss = seqno;
961 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
965 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
966 &hcrx->ccid3hcrx_li_hist, packet,
967 hcrx->ccid3hcrx_seqno_nonloss);
971 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
973 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
974 const struct dccp_options_received *opt_recv;
975 struct dccp_rx_hist_entry *packet;
977 u32 p_prev, rtt_prev;
978 suseconds_t r_sample, t_elapsed;
979 int loss, payload_size;
981 BUG_ON(hcrx == NULL);
983 opt_recv = &dccp_sk(sk)->dccps_options_received;
985 switch (DCCP_SKB_CB(skb)->dccpd_type) {
987 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
989 case DCCP_PKT_DATAACK:
990 if (opt_recv->dccpor_timestamp_echo == 0)
992 rtt_prev = hcrx->ccid3hcrx_rtt;
993 dccp_timestamp(sk, &now);
994 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
995 r_sample = timeval_usecs(&now);
996 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
998 DCCP_BUG_ON(r_sample < 0);
999 if (unlikely(r_sample <= t_elapsed))
1000 DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
1001 r_sample, t_elapsed);
1003 r_sample -= t_elapsed;
1004 CCID3_RTT_SANITY_CHECK(r_sample);
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 (suseconds_t)hcrx->ccid3hcrx_rtt >= 0) {
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 = 0;
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_parse_options = ccid3_hc_tx_parse_options,
1212 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1213 .ccid_hc_rx_init = ccid3_hc_rx_init,
1214 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1215 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1216 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1217 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1218 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1219 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1220 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1223 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1224 module_param(ccid3_debug, int, 0444);
1225 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1228 static __init int ccid3_module_init(void)
1232 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1233 if (ccid3_rx_hist == NULL)
1236 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1237 if (ccid3_tx_hist == NULL)
1240 ccid3_li_hist = dccp_li_hist_new("ccid3");
1241 if (ccid3_li_hist == NULL)
1244 rc = ccid_register(&ccid3);
1246 goto out_free_loss_interval_history;
1250 out_free_loss_interval_history:
1251 dccp_li_hist_delete(ccid3_li_hist);
1252 ccid3_li_hist = NULL;
1254 dccp_tx_hist_delete(ccid3_tx_hist);
1255 ccid3_tx_hist = NULL;
1257 dccp_rx_hist_delete(ccid3_rx_hist);
1258 ccid3_rx_hist = NULL;
1261 module_init(ccid3_module_init);
1263 static __exit void ccid3_module_exit(void)
1265 ccid_unregister(&ccid3);
1267 if (ccid3_tx_hist != NULL) {
1268 dccp_tx_hist_delete(ccid3_tx_hist);
1269 ccid3_tx_hist = NULL;
1271 if (ccid3_rx_hist != NULL) {
1272 dccp_rx_hist_delete(ccid3_rx_hist);
1273 ccid3_rx_hist = NULL;
1275 if (ccid3_li_hist != NULL) {
1276 dccp_li_hist_delete(ccid3_li_hist);
1277 ccid3_li_hist = NULL;
1280 module_exit(ccid3_module_exit);
1282 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1283 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1284 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1285 MODULE_LICENSE("GPL");
1286 MODULE_ALIAS("net-dccp-ccid-3");