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.
165 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
166 * The algorithm is not applicable if RTT < 4 microseconds.
168 static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
174 if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */
177 delta = timeval_delta(now, &hctx->ccid3hctx_t_last_win_count);
178 DCCP_BUG_ON(delta < 0);
180 quarter_rtts = (u32)delta / (hctx->ccid3hctx_rtt / 4);
182 if (quarter_rtts > 0) {
183 hctx->ccid3hctx_t_last_win_count = *now;
184 hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5);
185 hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
187 ccid3_pr_debug("now at %#X\n", hctx->ccid3hctx_last_win_count);
191 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
193 struct sock *sk = (struct sock *)data;
194 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
195 unsigned long t_nfb = USEC_PER_SEC / 5;
198 if (sock_owned_by_user(sk)) {
199 /* Try again later. */
200 /* XXX: set some sensible MIB */
204 ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
205 ccid3_tx_state_name(hctx->ccid3hctx_state));
207 switch (hctx->ccid3hctx_state) {
208 case TFRC_SSTATE_NO_FBACK:
209 /* RFC 3448, 4.4: Halve send rate directly */
210 hctx->ccid3hctx_x = max_t(u32, hctx->ccid3hctx_x / 2,
211 (hctx->ccid3hctx_s << 6)/TFRC_T_MBI);
213 ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %u "
216 ccid3_tx_state_name(hctx->ccid3hctx_state),
217 (unsigned)(hctx->ccid3hctx_x >> 6));
218 /* The value of R is still undefined and so we can not recompute
219 * the timout value. Keep initial value as per [RFC 4342, 5]. */
220 t_nfb = TFRC_INITIAL_TIMEOUT;
221 ccid3_update_send_time(hctx);
223 case TFRC_SSTATE_FBACK:
225 * Check if IDLE since last timeout and recv rate is less than
226 * 4 packets (in units of 64*bytes/sec) per RTT
228 if (!hctx->ccid3hctx_idle ||
229 (hctx->ccid3hctx_x_recv >= 4 *
230 scaled_div(hctx->ccid3hctx_s << 6, hctx->ccid3hctx_rtt))) {
233 ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
235 ccid3_tx_state_name(hctx->ccid3hctx_state));
238 * Modify the cached value of X_recv [RFC 3448, 4.4]
240 * If (p == 0 || X_calc > 2 * X_recv)
241 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
243 * X_recv = X_calc / 4;
245 * Note that X_recv is scaled by 2^6 while X_calc is not
247 BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
249 if (hctx->ccid3hctx_p == 0 ||
250 hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5)) {
252 hctx->ccid3hctx_x_recv =
253 max_t(u64, hctx->ccid3hctx_x_recv / 2,
254 (hctx->ccid3hctx_s << 6) /
257 if (hctx->ccid3hctx_p == 0)
258 dccp_timestamp(sk, &now);
260 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc << 4;
262 /* Now recalculate X [RFC 3448, 4.3, step (4)] */
263 ccid3_hc_tx_update_x(sk, &now);
266 * Schedule no feedback timer to expire in
267 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
268 * See comments in packet_recv() regarding the value of t_RTO.
270 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
272 case TFRC_SSTATE_NO_SENT:
273 DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk);
275 case TFRC_SSTATE_TERM:
279 hctx->ccid3hctx_idle = 1;
282 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
283 jiffies + usecs_to_jiffies(t_nfb));
291 * > 0: delay (in msecs) that should pass before actually sending
292 * = 0: can send immediately
293 * < 0: error condition; do not send packet
295 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
297 struct dccp_sock *dp = dccp_sk(sk);
298 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
299 struct dccp_tx_hist_entry *new_packet;
303 BUG_ON(hctx == NULL);
306 * This function is called only for Data and DataAck packets. Sending
307 * zero-sized Data(Ack)s is theoretically possible, but for congestion
308 * control this case is pathological - ignore it.
310 if (unlikely(skb->len == 0))
313 /* See if last packet allocated was not sent */
314 new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
315 if (new_packet == NULL || new_packet->dccphtx_sent) {
316 new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
319 if (unlikely(new_packet == NULL)) {
320 DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
321 "send refused\n", dccp_role(sk), sk);
325 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
328 dccp_timestamp(sk, &now);
330 switch (hctx->ccid3hctx_state) {
331 case TFRC_SSTATE_NO_SENT:
332 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
333 jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
334 hctx->ccid3hctx_last_win_count = 0;
335 hctx->ccid3hctx_t_last_win_count = now;
336 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
338 /* Set initial sending rate X/s to 1pps (X is scaled by 2^6) */
339 ccid3_hc_tx_update_s(hctx, skb->len);
340 hctx->ccid3hctx_x = hctx->ccid3hctx_s << 6;
342 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
343 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
344 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
345 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
347 /* Set t_0 for initial packet */
348 hctx->ccid3hctx_t_nom = now;
350 case TFRC_SSTATE_NO_FBACK:
351 case TFRC_SSTATE_FBACK:
352 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
354 * Scheduling of packet transmissions [RFC 3448, 4.6]
356 * if (t_now > t_nom - delta)
357 * // send the packet now
359 * // send the packet in (t_nom - t_now) milliseconds.
361 if (delay - (suseconds_t)hctx->ccid3hctx_delta >= 0)
362 return delay / 1000L;
364 ccid3_hc_tx_update_win_count(hctx, &now);
366 case TFRC_SSTATE_TERM:
367 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
371 /* prepare to send now (add options etc.) */
372 dp->dccps_hc_tx_insert_options = 1;
373 new_packet->dccphtx_ccval = DCCP_SKB_CB(skb)->dccpd_ccval =
374 hctx->ccid3hctx_last_win_count;
375 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
380 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
382 const struct dccp_sock *dp = dccp_sk(sk);
383 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
385 struct dccp_tx_hist_entry *packet;
387 BUG_ON(hctx == NULL);
389 dccp_timestamp(sk, &now);
391 ccid3_hc_tx_update_s(hctx, len);
393 packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
394 if (unlikely(packet == NULL)) {
395 DCCP_WARN("packet doesn't exist in history!\n");
398 if (unlikely(packet->dccphtx_sent)) {
399 DCCP_WARN("no unsent packet in history!\n");
402 packet->dccphtx_tstamp = now;
403 packet->dccphtx_seqno = dp->dccps_gss;
404 hctx->ccid3hctx_idle = 0;
405 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
406 packet->dccphtx_sent = 1;
409 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
411 const struct dccp_sock *dp = dccp_sk(sk);
412 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
413 struct ccid3_options_received *opt_recv;
414 struct dccp_tx_hist_entry *packet;
418 long r_sample, t_elapsed;
420 BUG_ON(hctx == NULL);
422 /* we are only interested in ACKs */
423 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
424 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
427 opt_recv = &hctx->ccid3hctx_options_received;
429 switch (hctx->ccid3hctx_state) {
430 case TFRC_SSTATE_NO_FBACK:
431 case TFRC_SSTATE_FBACK:
432 /* get packet from history to look up t_recvdata */
433 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
434 DCCP_SKB_CB(skb)->dccpd_ack_seq);
435 if (unlikely(packet == NULL)) {
436 DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
437 "in history!\n", dccp_role(sk), sk,
438 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
439 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
443 /* Update receive rate in units of 64 * bytes/second */
444 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate << 6;
446 /* Update loss event rate */
447 pinv = opt_recv->ccid3or_loss_event_rate;
448 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
449 hctx->ccid3hctx_p = 0;
450 else /* can not exceed 100% */
451 hctx->ccid3hctx_p = 1000000 / pinv;
453 dccp_timestamp(sk, &now);
456 * Calculate new round trip sample as per [RFC 3448, 4.3] by
457 * R_sample = (now - t_recvdata) - t_elapsed
459 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
460 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
462 DCCP_BUG_ON(r_sample < 0);
463 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;
468 CCID3_RTT_SANITY_CHECK(r_sample);
470 /* Update RTT estimate by
471 * If (No feedback recv)
474 * R = q * R + (1 - q) * R_sample;
476 * q is a constant, RFC 3448 recomments 0.9
478 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
480 * Larger Initial Windows [RFC 4342, sec. 5]
481 * We deviate in that we use `s' instead of `MSS'.
483 u16 w_init = min( 4 * hctx->ccid3hctx_s,
484 max(2 * hctx->ccid3hctx_s, 4380));
485 hctx->ccid3hctx_rtt = r_sample;
486 hctx->ccid3hctx_x = scaled_div(w_init<< 6, r_sample);
487 hctx->ccid3hctx_t_ld = now;
489 ccid3_update_send_time(hctx);
491 ccid3_pr_debug("%s(%p), s=%u, w_init=%u, "
492 "R_sample=%ldus, X=%u\n", dccp_role(sk),
493 sk, hctx->ccid3hctx_s, w_init, r_sample,
494 (unsigned)(hctx->ccid3hctx_x >> 6));
496 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
498 hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
499 (u32)r_sample ) / 10;
501 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
502 if (hctx->ccid3hctx_p > 0)
503 hctx->ccid3hctx_x_calc =
504 tfrc_calc_x(hctx->ccid3hctx_s,
507 ccid3_hc_tx_update_x(sk, &now);
509 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%ldus), s=%u, "
510 "p=%u, X_calc=%u, X=%u\n", dccp_role(sk),
511 sk, hctx->ccid3hctx_rtt, r_sample,
512 hctx->ccid3hctx_s, hctx->ccid3hctx_p,
513 hctx->ccid3hctx_x_calc,
514 (unsigned)(hctx->ccid3hctx_x >> 6));
517 /* unschedule no feedback timer */
518 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
520 /* remove all packets older than the one acked from history */
521 dccp_tx_hist_purge_older(ccid3_tx_hist,
522 &hctx->ccid3hctx_hist, packet);
524 * As we have calculated new ipi, delta, t_nom it is possible that
525 * we now can send a packet, so wake up dccp_wait_for_ccid
527 sk->sk_write_space(sk);
530 * Update timeout interval for the nofeedback timer.
531 * We use a configuration option to increase the lower bound.
532 * This can help avoid triggering the nofeedback timer too often
533 * ('spinning') on LANs with small RTTs.
535 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
536 CONFIG_IP_DCCP_CCID3_RTO *
537 (USEC_PER_SEC/1000) );
539 * Schedule no feedback timer to expire in
540 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
542 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
544 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
545 "expire in %lu jiffies (%luus)\n",
547 usecs_to_jiffies(t_nfb), t_nfb);
549 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
550 jiffies + usecs_to_jiffies(t_nfb));
553 hctx->ccid3hctx_idle = 1;
555 case TFRC_SSTATE_NO_SENT:
556 /* XXX when implementing bidirectional rx/tx check this again */
557 DCCP_WARN("Illegal ACK received - no packet sent\n");
559 case TFRC_SSTATE_TERM: /* ignore feedback when closing */
564 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
565 unsigned char len, u16 idx,
566 unsigned char *value)
569 const struct dccp_sock *dp = dccp_sk(sk);
570 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
571 struct ccid3_options_received *opt_recv;
573 BUG_ON(hctx == NULL);
575 opt_recv = &hctx->ccid3hctx_options_received;
577 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
578 opt_recv->ccid3or_seqno = dp->dccps_gsr;
579 opt_recv->ccid3or_loss_event_rate = ~0;
580 opt_recv->ccid3or_loss_intervals_idx = 0;
581 opt_recv->ccid3or_loss_intervals_len = 0;
582 opt_recv->ccid3or_receive_rate = 0;
586 case TFRC_OPT_LOSS_EVENT_RATE:
587 if (unlikely(len != 4)) {
588 DCCP_WARN("%s, sk=%p, invalid len %d "
589 "for TFRC_OPT_LOSS_EVENT_RATE\n",
590 dccp_role(sk), sk, len);
593 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
594 ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
596 opt_recv->ccid3or_loss_event_rate);
599 case TFRC_OPT_LOSS_INTERVALS:
600 opt_recv->ccid3or_loss_intervals_idx = idx;
601 opt_recv->ccid3or_loss_intervals_len = len;
602 ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
604 opt_recv->ccid3or_loss_intervals_idx,
605 opt_recv->ccid3or_loss_intervals_len);
607 case TFRC_OPT_RECEIVE_RATE:
608 if (unlikely(len != 4)) {
609 DCCP_WARN("%s, sk=%p, invalid len %d "
610 "for TFRC_OPT_RECEIVE_RATE\n",
611 dccp_role(sk), sk, len);
614 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
615 ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
617 opt_recv->ccid3or_receive_rate);
625 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
627 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
629 hctx->ccid3hctx_s = 0;
630 hctx->ccid3hctx_rtt = 0;
631 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
632 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
634 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
635 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
636 init_timer(&hctx->ccid3hctx_no_feedback_timer);
641 static void ccid3_hc_tx_exit(struct sock *sk)
643 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
645 BUG_ON(hctx == NULL);
647 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
648 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
650 /* Empty packet history */
651 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
655 * RX Half Connection methods
658 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
659 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
661 static char *ccid3_rx_state_names[] = {
662 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
663 [TFRC_RSTATE_DATA] = "DATA",
664 [TFRC_RSTATE_TERM] = "TERM",
667 return ccid3_rx_state_names[state];
671 static void ccid3_hc_rx_set_state(struct sock *sk,
672 enum ccid3_hc_rx_states state)
674 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
675 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
677 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
678 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
679 ccid3_rx_state_name(state));
680 WARN_ON(state == oldstate);
681 hcrx->ccid3hcrx_state = state;
684 static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
686 if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
687 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
689 hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
690 (9 * hcrx->ccid3hcrx_s + len) / 10;
693 static void ccid3_hc_rx_send_feedback(struct sock *sk)
695 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
696 struct dccp_sock *dp = dccp_sk(sk);
697 struct dccp_rx_hist_entry *packet;
701 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
703 dccp_timestamp(sk, &now);
705 switch (hcrx->ccid3hcrx_state) {
706 case TFRC_RSTATE_NO_DATA:
707 hcrx->ccid3hcrx_x_recv = 0;
709 case TFRC_RSTATE_DATA:
710 delta = timeval_delta(&now,
711 &hcrx->ccid3hcrx_tstamp_last_feedback);
712 DCCP_BUG_ON(delta < 0);
713 hcrx->ccid3hcrx_x_recv =
714 scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
716 case TFRC_RSTATE_TERM:
717 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
721 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
722 if (unlikely(packet == NULL)) {
723 DCCP_WARN("%s, sk=%p, no data packet in history!\n",
728 hcrx->ccid3hcrx_tstamp_last_feedback = now;
729 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
730 hcrx->ccid3hcrx_bytes_recv = 0;
732 /* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
733 delta = timeval_delta(&now, &packet->dccphrx_tstamp);
734 DCCP_BUG_ON(delta < 0);
735 hcrx->ccid3hcrx_elapsed_time = delta / 10;
737 if (hcrx->ccid3hcrx_p == 0)
738 hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
739 else if (hcrx->ccid3hcrx_p > 1000000) {
740 DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
741 hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
743 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
745 dp->dccps_hc_rx_insert_options = 1;
749 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
751 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
754 BUG_ON(hcrx == NULL);
756 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
759 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
761 if (dccp_packet_without_ack(skb))
764 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
765 pinv = htonl(hcrx->ccid3hcrx_pinv);
767 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
768 dccp_insert_option_elapsed_time(sk, skb,
769 hcrx->ccid3hcrx_elapsed_time)) ||
770 dccp_insert_option_timestamp(sk, skb) ||
771 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
772 &pinv, sizeof(pinv)) ||
773 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
774 &x_recv, sizeof(x_recv)))
780 /* calculate first loss interval
782 * returns estimated loss interval in usecs */
784 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
786 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
787 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
789 suseconds_t rtt, delta;
790 struct timeval tstamp = { 0, };
796 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
798 if (dccp_rx_hist_entry_data_packet(entry)) {
803 tstamp = entry->dccphrx_tstamp;
804 win_count = entry->dccphrx_ccval;
808 interval = win_count - entry->dccphrx_ccval;
810 interval += TFRC_WIN_COUNT_LIMIT;
818 if (unlikely(step == 0)) {
819 DCCP_WARN("%s, sk=%p, packet history has no data packets!\n",
824 if (unlikely(interval == 0)) {
825 DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0."
826 "Defaulting to 1\n", dccp_role(sk), sk);
831 DCCP_CRIT("tail is null\n");
835 delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
836 DCCP_BUG_ON(delta < 0);
838 rtt = delta * 4 / interval;
839 ccid3_pr_debug("%s, sk=%p, approximated RTT to %ldus\n",
840 dccp_role(sk), sk, rtt);
843 * Determine the length of the first loss interval via inverse lookup.
844 * Assume that X_recv can be computed by the throughput equation
848 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
850 if (rtt == 0) { /* would result in divide-by-zero */
851 DCCP_WARN("RTT==0, returning 1/p = 1\n");
855 dccp_timestamp(sk, &tstamp);
856 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
857 DCCP_BUG_ON(delta <= 0);
859 x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
860 if (x_recv == 0) { /* would also trigger divide-by-zero */
861 DCCP_WARN("X_recv==0\n");
862 if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
863 DCCP_BUG("stored value of X_recv is zero");
868 fval = scaled_div(hcrx->ccid3hcrx_s, rtt);
869 fval = scaled_div32(fval, x_recv);
870 p = tfrc_calc_x_reverse_lookup(fval);
872 ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
873 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
881 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
883 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
884 struct dccp_li_hist_entry *head;
887 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
888 if (!dccp_li_hist_interval_new(ccid3_li_hist,
889 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
892 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
893 struct dccp_li_hist_entry, dccplih_node);
894 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
896 struct dccp_li_hist_entry *entry;
897 struct list_head *tail;
899 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
900 struct dccp_li_hist_entry, dccplih_node);
901 /* FIXME win count check removed as was wrong */
902 /* should make this check with receive history */
903 /* and compare there as per section 10.2 of RFC4342 */
905 /* new loss event detected */
906 /* calculate last interval length */
907 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
908 entry = dccp_li_hist_entry_new(ccid3_li_hist, GFP_ATOMIC);
911 DCCP_BUG("out of memory - can not allocate entry");
915 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
917 tail = hcrx->ccid3hcrx_li_hist.prev;
919 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
921 /* Create the newest interval */
922 entry->dccplih_seqno = seq_loss;
923 entry->dccplih_interval = seq_temp;
924 entry->dccplih_win_count = win_loss;
928 static int ccid3_hc_rx_detect_loss(struct sock *sk,
929 struct dccp_rx_hist_entry *packet)
931 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
932 struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
933 u64 seqno = packet->dccphrx_seqno;
939 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
942 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
943 hcrx->ccid3hcrx_seqno_nonloss = seqno;
944 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
949 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
950 > TFRC_RECV_NUM_LATE_LOSS) {
952 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
953 hcrx->ccid3hcrx_ccval_nonloss);
954 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
955 dccp_inc_seqno(&tmp_seqno);
956 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
957 dccp_inc_seqno(&tmp_seqno);
958 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
959 tmp_seqno, &ccval)) {
960 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
961 hcrx->ccid3hcrx_ccval_nonloss = ccval;
962 dccp_inc_seqno(&tmp_seqno);
966 /* FIXME - this code could be simplified with above while */
967 /* but works at moment */
968 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
969 hcrx->ccid3hcrx_seqno_nonloss = seqno;
970 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
974 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
975 &hcrx->ccid3hcrx_li_hist, packet,
976 hcrx->ccid3hcrx_seqno_nonloss);
980 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
982 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
983 const struct dccp_options_received *opt_recv;
984 struct dccp_rx_hist_entry *packet;
986 u32 p_prev, rtt_prev;
987 suseconds_t r_sample, t_elapsed;
988 int loss, payload_size;
990 BUG_ON(hcrx == NULL);
992 opt_recv = &dccp_sk(sk)->dccps_options_received;
994 switch (DCCP_SKB_CB(skb)->dccpd_type) {
996 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
998 case DCCP_PKT_DATAACK:
999 if (opt_recv->dccpor_timestamp_echo == 0)
1001 rtt_prev = hcrx->ccid3hcrx_rtt;
1002 dccp_timestamp(sk, &now);
1003 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
1004 r_sample = timeval_usecs(&now);
1005 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
1007 DCCP_BUG_ON(r_sample < 0);
1008 if (unlikely(r_sample <= t_elapsed))
1009 DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
1010 r_sample, t_elapsed);
1012 r_sample -= t_elapsed;
1013 CCID3_RTT_SANITY_CHECK(r_sample);
1015 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1016 hcrx->ccid3hcrx_rtt = r_sample;
1018 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
1021 if (rtt_prev != hcrx->ccid3hcrx_rtt)
1022 ccid3_pr_debug("%s, New RTT=%uus, elapsed time=%u\n",
1023 dccp_role(sk), hcrx->ccid3hcrx_rtt,
1024 opt_recv->dccpor_elapsed_time);
1028 default: /* We're not interested in other packet types, move along */
1032 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
1034 if (unlikely(packet == NULL)) {
1035 DCCP_WARN("%s, sk=%p, Not enough mem to add rx packet "
1036 "to history, consider it lost!\n", dccp_role(sk), sk);
1040 loss = ccid3_hc_rx_detect_loss(sk, packet);
1042 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1045 payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
1046 ccid3_hc_rx_update_s(hcrx, payload_size);
1048 switch (hcrx->ccid3hcrx_state) {
1049 case TFRC_RSTATE_NO_DATA:
1050 ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial "
1053 dccp_state_name(sk->sk_state), skb);
1054 ccid3_hc_rx_send_feedback(sk);
1055 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1057 case TFRC_RSTATE_DATA:
1058 hcrx->ccid3hcrx_bytes_recv += payload_size;
1062 dccp_timestamp(sk, &now);
1063 if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
1064 (suseconds_t)hcrx->ccid3hcrx_rtt >= 0) {
1065 hcrx->ccid3hcrx_tstamp_last_ack = now;
1066 ccid3_hc_rx_send_feedback(sk);
1069 case TFRC_RSTATE_TERM:
1070 DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk);
1074 /* Dealing with packet loss */
1075 ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n",
1076 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1078 p_prev = hcrx->ccid3hcrx_p;
1080 /* Calculate loss event rate */
1081 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1082 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1084 /* Scaling up by 1000000 as fixed decimal */
1086 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1088 DCCP_BUG("empty loss history");
1090 if (hcrx->ccid3hcrx_p > p_prev) {
1091 ccid3_hc_rx_send_feedback(sk);
1096 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1098 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1100 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
1102 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1103 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1104 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1105 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1106 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1107 hcrx->ccid3hcrx_s = 0;
1108 hcrx->ccid3hcrx_rtt = 0;
1112 static void ccid3_hc_rx_exit(struct sock *sk)
1114 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1116 BUG_ON(hcrx == NULL);
1118 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1120 /* Empty packet history */
1121 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1123 /* Empty loss interval history */
1124 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1127 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1129 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1131 /* Listen socks doesn't have a private CCID block */
1132 if (sk->sk_state == DCCP_LISTEN)
1135 BUG_ON(hcrx == NULL);
1137 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1138 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1139 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1142 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1144 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1146 /* Listen socks doesn't have a private CCID block */
1147 if (sk->sk_state == DCCP_LISTEN)
1150 BUG_ON(hctx == NULL);
1152 info->tcpi_rto = hctx->ccid3hctx_t_rto;
1153 info->tcpi_rtt = hctx->ccid3hctx_rtt;
1156 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1157 u32 __user *optval, int __user *optlen)
1159 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1162 /* Listen socks doesn't have a private CCID block */
1163 if (sk->sk_state == DCCP_LISTEN)
1167 case DCCP_SOCKOPT_CCID_RX_INFO:
1168 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1170 len = sizeof(hcrx->ccid3hcrx_tfrc);
1171 val = &hcrx->ccid3hcrx_tfrc;
1174 return -ENOPROTOOPT;
1177 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1183 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1184 u32 __user *optval, int __user *optlen)
1186 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1189 /* Listen socks doesn't have a private CCID block */
1190 if (sk->sk_state == DCCP_LISTEN)
1194 case DCCP_SOCKOPT_CCID_TX_INFO:
1195 if (len < sizeof(hctx->ccid3hctx_tfrc))
1197 len = sizeof(hctx->ccid3hctx_tfrc);
1198 val = &hctx->ccid3hctx_tfrc;
1201 return -ENOPROTOOPT;
1204 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1210 static struct ccid_operations ccid3 = {
1211 .ccid_id = DCCPC_CCID3,
1212 .ccid_name = "ccid3",
1213 .ccid_owner = THIS_MODULE,
1214 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1215 .ccid_hc_tx_init = ccid3_hc_tx_init,
1216 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1217 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1218 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1219 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1220 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1221 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1222 .ccid_hc_rx_init = ccid3_hc_rx_init,
1223 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1224 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1225 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1226 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1227 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1228 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1229 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1232 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1233 module_param(ccid3_debug, int, 0444);
1234 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1237 static __init int ccid3_module_init(void)
1241 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1242 if (ccid3_rx_hist == NULL)
1245 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1246 if (ccid3_tx_hist == NULL)
1249 ccid3_li_hist = dccp_li_hist_new("ccid3");
1250 if (ccid3_li_hist == NULL)
1253 rc = ccid_register(&ccid3);
1255 goto out_free_loss_interval_history;
1259 out_free_loss_interval_history:
1260 dccp_li_hist_delete(ccid3_li_hist);
1261 ccid3_li_hist = NULL;
1263 dccp_tx_hist_delete(ccid3_tx_hist);
1264 ccid3_tx_hist = NULL;
1266 dccp_rx_hist_delete(ccid3_rx_hist);
1267 ccid3_rx_hist = NULL;
1270 module_init(ccid3_module_init);
1272 static __exit void ccid3_module_exit(void)
1274 ccid_unregister(&ccid3);
1276 if (ccid3_tx_hist != NULL) {
1277 dccp_tx_hist_delete(ccid3_tx_hist);
1278 ccid3_tx_hist = NULL;
1280 if (ccid3_rx_hist != NULL) {
1281 dccp_rx_hist_delete(ccid3_rx_hist);
1282 ccid3_rx_hist = NULL;
1284 if (ccid3_li_hist != NULL) {
1285 dccp_li_hist_delete(ccid3_li_hist);
1286 ccid3_li_hist = NULL;
1289 module_exit(ccid3_module_exit);
1291 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1292 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1293 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1294 MODULE_LICENSE("GPL");
1295 MODULE_ALIAS("net-dccp-ccid-3");