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(((__u64)hctx->ccid3hctx_x_calc) << 6,
127 hctx->ccid3hctx_x_recv * 2 );
128 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
129 (((__u64)hctx->ccid3hctx_s) << 6) /
132 } else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) -
133 (suseconds_t)hctx->ccid3hctx_rtt >= 0 ) {
136 max(2 * min(hctx->ccid3hctx_x, hctx->ccid3hctx_x_recv),
137 scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
138 hctx->ccid3hctx_rtt ) );
139 hctx->ccid3hctx_t_ld = *now;
142 if (hctx->ccid3hctx_x != old_x)
143 ccid3_update_send_time(hctx);
147 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
148 * @len: DCCP packet payload size in bytes
150 static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
152 if (unlikely(len == 0))
153 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
155 hctx->ccid3hctx_s = hctx->ccid3hctx_s == 0 ? len :
156 (9 * hctx->ccid3hctx_s + len) / 10;
158 * Note: We could do a potential optimisation here - when `s' changes,
159 * recalculate sending rate and consequently t_ipi, t_delta, and
160 * t_now. This is however non-standard, and the benefits are not
161 * clear, so it is currently left out.
166 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
167 * The algorithm is not applicable if RTT < 4 microseconds.
169 static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
175 if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */
178 delta = timeval_delta(now, &hctx->ccid3hctx_t_last_win_count);
179 DCCP_BUG_ON(delta < 0);
181 quarter_rtts = (u32)delta / (hctx->ccid3hctx_rtt / 4);
183 if (quarter_rtts > 0) {
184 hctx->ccid3hctx_t_last_win_count = *now;
185 hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5);
186 hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
188 ccid3_pr_debug("now at %#X\n", hctx->ccid3hctx_last_win_count);
192 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
194 struct sock *sk = (struct sock *)data;
195 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
196 unsigned long t_nfb = USEC_PER_SEC / 5;
199 if (sock_owned_by_user(sk)) {
200 /* Try again later. */
201 /* XXX: set some sensible MIB */
205 ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
206 ccid3_tx_state_name(hctx->ccid3hctx_state));
208 switch (hctx->ccid3hctx_state) {
209 case TFRC_SSTATE_NO_FBACK:
210 /* RFC 3448, 4.4: Halve send rate directly */
211 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
212 (((__u64)hctx->ccid3hctx_s) << 6) /
215 ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u "
216 "bytes/s\n", dccp_role(sk), sk,
217 ccid3_tx_state_name(hctx->ccid3hctx_state),
218 (unsigned)(hctx->ccid3hctx_x >> 6));
219 /* The value of R is still undefined and so we can not recompute
220 * the timout value. Keep initial value as per [RFC 4342, 5]. */
221 t_nfb = TFRC_INITIAL_TIMEOUT;
222 ccid3_update_send_time(hctx);
224 case TFRC_SSTATE_FBACK:
226 * Check if IDLE since last timeout and recv rate is less than
227 * 4 packets (in units of 64*bytes/sec) per RTT
229 if (!hctx->ccid3hctx_idle ||
230 (hctx->ccid3hctx_x_recv >= 4 *
231 scaled_div(((__u64)hctx->ccid3hctx_s) << 6, hctx->ccid3hctx_rtt))) {
234 ccid3_pr_debug("%s(%p, state=%s), not idle\n",
236 ccid3_tx_state_name(hctx->ccid3hctx_state));
239 * Modify the cached value of X_recv [RFC 3448, 4.4]
241 * If (p == 0 || X_calc > 2 * X_recv)
242 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
244 * X_recv = X_calc / 4;
246 * Note that X_recv is scaled by 2^6 while X_calc is not
248 BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
250 if (hctx->ccid3hctx_p == 0 ||
251 hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5)) {
253 hctx->ccid3hctx_x_recv =
254 max(hctx->ccid3hctx_x_recv / 2,
255 (((__u64)hctx->ccid3hctx_s) << 6) /
258 if (hctx->ccid3hctx_p == 0)
259 dccp_timestamp(sk, &now);
261 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
262 hctx->ccid3hctx_x_recv <<= 4;
264 /* Now recalculate X [RFC 3448, 4.3, step (4)] */
265 ccid3_hc_tx_update_x(sk, &now);
268 * Schedule no feedback timer to expire in
269 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
270 * See comments in packet_recv() regarding the value of t_RTO.
272 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
274 case TFRC_SSTATE_NO_SENT:
275 DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk);
277 case TFRC_SSTATE_TERM:
281 hctx->ccid3hctx_idle = 1;
284 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
285 jiffies + usecs_to_jiffies(t_nfb));
293 * > 0: delay (in msecs) that should pass before actually sending
294 * = 0: can send immediately
295 * < 0: error condition; do not send packet
297 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
299 struct dccp_sock *dp = dccp_sk(sk);
300 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
304 BUG_ON(hctx == NULL);
307 * This function is called only for Data and DataAck packets. Sending
308 * zero-sized Data(Ack)s is theoretically possible, but for congestion
309 * control this case is pathological - ignore it.
311 if (unlikely(skb->len == 0))
314 dccp_timestamp(sk, &now);
316 switch (hctx->ccid3hctx_state) {
317 case TFRC_SSTATE_NO_SENT:
318 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
319 jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
320 hctx->ccid3hctx_last_win_count = 0;
321 hctx->ccid3hctx_t_last_win_count = now;
322 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
324 /* Set initial sending rate X/s to 1pps (X is scaled by 2^6) */
325 ccid3_hc_tx_update_s(hctx, skb->len);
326 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
327 hctx->ccid3hctx_x <<= 6;
329 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
330 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
331 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
332 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
334 /* Set t_0 for initial packet */
335 hctx->ccid3hctx_t_nom = now;
337 case TFRC_SSTATE_NO_FBACK:
338 case TFRC_SSTATE_FBACK:
339 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
341 * Scheduling of packet transmissions [RFC 3448, 4.6]
343 * if (t_now > t_nom - delta)
344 * // send the packet now
346 * // send the packet in (t_nom - t_now) milliseconds.
348 if (delay - (suseconds_t)hctx->ccid3hctx_delta >= 0)
349 return delay / 1000L;
351 ccid3_hc_tx_update_win_count(hctx, &now);
353 case TFRC_SSTATE_TERM:
354 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
358 /* prepare to send now (add options etc.) */
359 dp->dccps_hc_tx_insert_options = 1;
360 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
362 /* set the nominal send time for the next following packet */
363 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
368 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
370 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
372 struct dccp_tx_hist_entry *packet;
374 BUG_ON(hctx == NULL);
376 ccid3_hc_tx_update_s(hctx, len);
378 packet = dccp_tx_hist_entry_new(ccid3_tx_hist, GFP_ATOMIC);
379 if (unlikely(packet == NULL)) {
380 DCCP_CRIT("packet history - out of memory!");
383 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
385 dccp_timestamp(sk, &now);
386 packet->dccphtx_tstamp = now;
387 packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
388 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
389 packet->dccphtx_sent = 1;
390 hctx->ccid3hctx_idle = 0;
393 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
395 const struct dccp_sock *dp = dccp_sk(sk);
396 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
397 struct ccid3_options_received *opt_recv;
398 struct dccp_tx_hist_entry *packet;
402 long r_sample, t_elapsed;
404 BUG_ON(hctx == NULL);
406 /* we are only interested in ACKs */
407 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
408 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
411 opt_recv = &hctx->ccid3hctx_options_received;
413 switch (hctx->ccid3hctx_state) {
414 case TFRC_SSTATE_NO_FBACK:
415 case TFRC_SSTATE_FBACK:
416 /* get packet from history to look up t_recvdata */
417 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
418 DCCP_SKB_CB(skb)->dccpd_ack_seq);
419 if (unlikely(packet == NULL)) {
420 DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
421 "in history!\n", dccp_role(sk), sk,
422 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
423 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
427 /* Update receive rate in units of 64 * bytes/second */
428 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
429 hctx->ccid3hctx_x_recv <<= 6;
431 /* Update loss event rate */
432 pinv = opt_recv->ccid3or_loss_event_rate;
433 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
434 hctx->ccid3hctx_p = 0;
435 else /* can not exceed 100% */
436 hctx->ccid3hctx_p = 1000000 / pinv;
438 dccp_timestamp(sk, &now);
441 * Calculate new round trip sample as per [RFC 3448, 4.3] by
442 * R_sample = (now - t_recvdata) - t_elapsed
444 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
445 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
447 DCCP_BUG_ON(r_sample < 0);
448 if (unlikely(r_sample <= t_elapsed))
449 DCCP_WARN("WARNING: r_sample=%ldus <= t_elapsed=%ldus\n",
450 r_sample, t_elapsed);
452 r_sample -= t_elapsed;
453 CCID3_RTT_SANITY_CHECK(r_sample);
455 /* Update RTT estimate by
456 * If (No feedback recv)
459 * R = q * R + (1 - q) * R_sample;
461 * q is a constant, RFC 3448 recomments 0.9
463 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
465 * Larger Initial Windows [RFC 4342, sec. 5]
466 * We deviate in that we use `s' instead of `MSS'.
468 __u64 w_init = min( 4 * hctx->ccid3hctx_s,
469 max(2 * hctx->ccid3hctx_s, 4380));
470 hctx->ccid3hctx_rtt = r_sample;
471 hctx->ccid3hctx_x = scaled_div(w_init << 6, r_sample);
472 hctx->ccid3hctx_t_ld = now;
474 ccid3_update_send_time(hctx);
476 ccid3_pr_debug("%s(%p), s=%u, w_init=%llu, "
477 "R_sample=%ldus, X=%u\n", dccp_role(sk),
478 sk, hctx->ccid3hctx_s, w_init, r_sample,
479 (unsigned)(hctx->ccid3hctx_x >> 6));
481 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
483 hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
484 (u32)r_sample ) / 10;
486 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
487 if (hctx->ccid3hctx_p > 0)
488 hctx->ccid3hctx_x_calc =
489 tfrc_calc_x(hctx->ccid3hctx_s,
492 ccid3_hc_tx_update_x(sk, &now);
494 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%ldus), s=%u, "
495 "p=%u, X_calc=%u, X_recv=%u, X=%u\n", dccp_role(sk),
496 sk, hctx->ccid3hctx_rtt, r_sample,
497 hctx->ccid3hctx_s, hctx->ccid3hctx_p,
498 hctx->ccid3hctx_x_calc,
499 (unsigned)(hctx->ccid3hctx_x_recv >> 6),
500 (unsigned)(hctx->ccid3hctx_x >> 6) );
503 /* unschedule no feedback timer */
504 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
506 /* remove all packets older than the one acked from history */
507 dccp_tx_hist_purge_older(ccid3_tx_hist,
508 &hctx->ccid3hctx_hist, packet);
510 * As we have calculated new ipi, delta, t_nom it is possible that
511 * we now can send a packet, so wake up dccp_wait_for_ccid
513 sk->sk_write_space(sk);
516 * Update timeout interval for the nofeedback timer.
517 * We use a configuration option to increase the lower bound.
518 * This can help avoid triggering the nofeedback timer too often
519 * ('spinning') on LANs with small RTTs.
521 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
522 CONFIG_IP_DCCP_CCID3_RTO *
523 (USEC_PER_SEC/1000) );
525 * Schedule no feedback timer to expire in
526 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
528 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
530 ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
531 "expire in %lu jiffies (%luus)\n", dccp_role(sk),
532 sk, usecs_to_jiffies(t_nfb), t_nfb);
534 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
535 jiffies + usecs_to_jiffies(t_nfb));
538 hctx->ccid3hctx_idle = 1;
540 case TFRC_SSTATE_NO_SENT:
541 /* XXX when implementing bidirectional rx/tx check this again */
542 DCCP_WARN("Illegal ACK received - no packet sent\n");
544 case TFRC_SSTATE_TERM: /* ignore feedback when closing */
549 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
550 unsigned char len, u16 idx,
551 unsigned char *value)
554 const struct dccp_sock *dp = dccp_sk(sk);
555 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
556 struct ccid3_options_received *opt_recv;
558 BUG_ON(hctx == NULL);
560 opt_recv = &hctx->ccid3hctx_options_received;
562 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
563 opt_recv->ccid3or_seqno = dp->dccps_gsr;
564 opt_recv->ccid3or_loss_event_rate = ~0;
565 opt_recv->ccid3or_loss_intervals_idx = 0;
566 opt_recv->ccid3or_loss_intervals_len = 0;
567 opt_recv->ccid3or_receive_rate = 0;
571 case TFRC_OPT_LOSS_EVENT_RATE:
572 if (unlikely(len != 4)) {
573 DCCP_WARN("%s(%p), invalid len %d "
574 "for TFRC_OPT_LOSS_EVENT_RATE\n",
575 dccp_role(sk), sk, len);
578 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
579 ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
581 opt_recv->ccid3or_loss_event_rate);
584 case TFRC_OPT_LOSS_INTERVALS:
585 opt_recv->ccid3or_loss_intervals_idx = idx;
586 opt_recv->ccid3or_loss_intervals_len = len;
587 ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
589 opt_recv->ccid3or_loss_intervals_idx,
590 opt_recv->ccid3or_loss_intervals_len);
592 case TFRC_OPT_RECEIVE_RATE:
593 if (unlikely(len != 4)) {
594 DCCP_WARN("%s(%p), invalid len %d "
595 "for TFRC_OPT_RECEIVE_RATE\n",
596 dccp_role(sk), sk, len);
599 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
600 ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
602 opt_recv->ccid3or_receive_rate);
610 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
612 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
614 hctx->ccid3hctx_s = 0;
615 hctx->ccid3hctx_rtt = 0;
616 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
617 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
619 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
620 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
621 init_timer(&hctx->ccid3hctx_no_feedback_timer);
626 static void ccid3_hc_tx_exit(struct sock *sk)
628 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
630 BUG_ON(hctx == NULL);
632 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
633 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
635 /* Empty packet history */
636 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
640 * RX Half Connection methods
643 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
644 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
646 static char *ccid3_rx_state_names[] = {
647 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
648 [TFRC_RSTATE_DATA] = "DATA",
649 [TFRC_RSTATE_TERM] = "TERM",
652 return ccid3_rx_state_names[state];
656 static void ccid3_hc_rx_set_state(struct sock *sk,
657 enum ccid3_hc_rx_states state)
659 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
660 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
662 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
663 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
664 ccid3_rx_state_name(state));
665 WARN_ON(state == oldstate);
666 hcrx->ccid3hcrx_state = state;
669 static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
671 if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
672 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
674 hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
675 (9 * hcrx->ccid3hcrx_s + len) / 10;
678 static void ccid3_hc_rx_send_feedback(struct sock *sk)
680 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
681 struct dccp_sock *dp = dccp_sk(sk);
682 struct dccp_rx_hist_entry *packet;
686 ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk);
688 dccp_timestamp(sk, &now);
690 switch (hcrx->ccid3hcrx_state) {
691 case TFRC_RSTATE_NO_DATA:
692 hcrx->ccid3hcrx_x_recv = 0;
694 case TFRC_RSTATE_DATA:
695 delta = timeval_delta(&now,
696 &hcrx->ccid3hcrx_tstamp_last_feedback);
697 DCCP_BUG_ON(delta < 0);
698 hcrx->ccid3hcrx_x_recv =
699 scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
701 case TFRC_RSTATE_TERM:
702 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
706 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
707 if (unlikely(packet == NULL)) {
708 DCCP_WARN("%s(%p), no data packet in history!\n",
713 hcrx->ccid3hcrx_tstamp_last_feedback = now;
714 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
715 hcrx->ccid3hcrx_bytes_recv = 0;
717 /* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
718 delta = timeval_delta(&now, &packet->dccphrx_tstamp);
719 DCCP_BUG_ON(delta < 0);
720 hcrx->ccid3hcrx_elapsed_time = delta / 10;
722 if (hcrx->ccid3hcrx_p == 0)
723 hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
724 else if (hcrx->ccid3hcrx_p > 1000000) {
725 DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
726 hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
728 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
730 dp->dccps_hc_rx_insert_options = 1;
734 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
736 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
739 BUG_ON(hcrx == NULL);
741 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
744 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
746 if (dccp_packet_without_ack(skb))
749 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
750 pinv = htonl(hcrx->ccid3hcrx_pinv);
752 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
753 dccp_insert_option_elapsed_time(sk, skb,
754 hcrx->ccid3hcrx_elapsed_time)) ||
755 dccp_insert_option_timestamp(sk, skb) ||
756 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
757 &pinv, sizeof(pinv)) ||
758 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
759 &x_recv, sizeof(x_recv)))
765 /* calculate first loss interval
767 * returns estimated loss interval in usecs */
769 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
771 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
772 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
774 suseconds_t rtt, delta;
775 struct timeval tstamp = { 0, };
781 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
783 if (dccp_rx_hist_entry_data_packet(entry)) {
788 tstamp = entry->dccphrx_tstamp;
789 win_count = entry->dccphrx_ccval;
793 interval = win_count - entry->dccphrx_ccval;
795 interval += TFRC_WIN_COUNT_LIMIT;
803 if (unlikely(step == 0)) {
804 DCCP_WARN("%s(%p), packet history has no data packets!\n",
809 if (unlikely(interval == 0)) {
810 DCCP_WARN("%s(%p), Could not find a win_count interval > 0."
811 "Defaulting to 1\n", dccp_role(sk), sk);
816 DCCP_CRIT("tail is null\n");
820 delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
821 DCCP_BUG_ON(delta < 0);
823 rtt = delta * 4 / interval;
824 ccid3_pr_debug("%s(%p), approximated RTT to %ldus\n",
825 dccp_role(sk), sk, rtt);
828 * Determine the length of the first loss interval via inverse lookup.
829 * Assume that X_recv can be computed by the throughput equation
833 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
835 if (rtt == 0) { /* would result in divide-by-zero */
836 DCCP_WARN("RTT==0, returning 1/p = 1\n");
840 dccp_timestamp(sk, &tstamp);
841 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
842 DCCP_BUG_ON(delta <= 0);
844 x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
845 if (x_recv == 0) { /* would also trigger divide-by-zero */
846 DCCP_WARN("X_recv==0\n");
847 if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
848 DCCP_BUG("stored value of X_recv is zero");
853 fval = scaled_div(hcrx->ccid3hcrx_s, rtt);
854 fval = scaled_div32(fval, x_recv);
855 p = tfrc_calc_x_reverse_lookup(fval);
857 ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
858 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
866 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
868 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
869 struct dccp_li_hist_entry *head;
872 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
873 if (!dccp_li_hist_interval_new(ccid3_li_hist,
874 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
877 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
878 struct dccp_li_hist_entry, dccplih_node);
879 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
881 struct dccp_li_hist_entry *entry;
882 struct list_head *tail;
884 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
885 struct dccp_li_hist_entry, dccplih_node);
886 /* FIXME win count check removed as was wrong */
887 /* should make this check with receive history */
888 /* and compare there as per section 10.2 of RFC4342 */
890 /* new loss event detected */
891 /* calculate last interval length */
892 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
893 entry = dccp_li_hist_entry_new(ccid3_li_hist, GFP_ATOMIC);
896 DCCP_BUG("out of memory - can not allocate entry");
900 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
902 tail = hcrx->ccid3hcrx_li_hist.prev;
904 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
906 /* Create the newest interval */
907 entry->dccplih_seqno = seq_loss;
908 entry->dccplih_interval = seq_temp;
909 entry->dccplih_win_count = win_loss;
913 static int ccid3_hc_rx_detect_loss(struct sock *sk,
914 struct dccp_rx_hist_entry *packet)
916 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
917 struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
918 u64 seqno = packet->dccphrx_seqno;
924 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
927 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
928 hcrx->ccid3hcrx_seqno_nonloss = seqno;
929 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
934 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
935 > TFRC_RECV_NUM_LATE_LOSS) {
937 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
938 hcrx->ccid3hcrx_ccval_nonloss);
939 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
940 dccp_inc_seqno(&tmp_seqno);
941 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
942 dccp_inc_seqno(&tmp_seqno);
943 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
944 tmp_seqno, &ccval)) {
945 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
946 hcrx->ccid3hcrx_ccval_nonloss = ccval;
947 dccp_inc_seqno(&tmp_seqno);
951 /* FIXME - this code could be simplified with above while */
952 /* but works at moment */
953 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
954 hcrx->ccid3hcrx_seqno_nonloss = seqno;
955 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
959 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
960 &hcrx->ccid3hcrx_li_hist, packet,
961 hcrx->ccid3hcrx_seqno_nonloss);
965 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
967 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
968 const struct dccp_options_received *opt_recv;
969 struct dccp_rx_hist_entry *packet;
971 u32 p_prev, rtt_prev;
972 suseconds_t r_sample, t_elapsed;
973 int loss, payload_size;
975 BUG_ON(hcrx == NULL);
977 opt_recv = &dccp_sk(sk)->dccps_options_received;
979 switch (DCCP_SKB_CB(skb)->dccpd_type) {
981 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
983 case DCCP_PKT_DATAACK:
984 if (opt_recv->dccpor_timestamp_echo == 0)
986 rtt_prev = hcrx->ccid3hcrx_rtt;
987 dccp_timestamp(sk, &now);
988 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
989 r_sample = timeval_usecs(&now);
990 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
992 DCCP_BUG_ON(r_sample < 0);
993 if (unlikely(r_sample <= t_elapsed))
994 DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
995 r_sample, t_elapsed);
997 r_sample -= t_elapsed;
998 CCID3_RTT_SANITY_CHECK(r_sample);
1000 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1001 hcrx->ccid3hcrx_rtt = r_sample;
1003 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
1006 if (rtt_prev != hcrx->ccid3hcrx_rtt)
1007 ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n",
1008 dccp_role(sk), sk, hcrx->ccid3hcrx_rtt,
1009 opt_recv->dccpor_elapsed_time);
1013 default: /* We're not interested in other packet types, move along */
1017 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
1019 if (unlikely(packet == NULL)) {
1020 DCCP_WARN("%s(%p), Not enough mem to add rx packet "
1021 "to history, consider it lost!\n", dccp_role(sk), sk);
1025 loss = ccid3_hc_rx_detect_loss(sk, packet);
1027 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1030 payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
1031 ccid3_hc_rx_update_s(hcrx, payload_size);
1033 switch (hcrx->ccid3hcrx_state) {
1034 case TFRC_RSTATE_NO_DATA:
1035 ccid3_pr_debug("%s(%p, state=%s), skb=%p, sending initial "
1036 "feedback\n", dccp_role(sk), sk,
1037 dccp_state_name(sk->sk_state), skb);
1038 ccid3_hc_rx_send_feedback(sk);
1039 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1041 case TFRC_RSTATE_DATA:
1042 hcrx->ccid3hcrx_bytes_recv += payload_size;
1046 dccp_timestamp(sk, &now);
1047 if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
1048 (suseconds_t)hcrx->ccid3hcrx_rtt >= 0) {
1049 hcrx->ccid3hcrx_tstamp_last_ack = now;
1050 ccid3_hc_rx_send_feedback(sk);
1053 case TFRC_RSTATE_TERM:
1054 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
1058 /* Dealing with packet loss */
1059 ccid3_pr_debug("%s(%p, state=%s), data loss! Reacting...\n",
1060 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1062 p_prev = hcrx->ccid3hcrx_p;
1064 /* Calculate loss event rate */
1065 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1066 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1068 /* Scaling up by 1000000 as fixed decimal */
1070 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1072 DCCP_BUG("empty loss history");
1074 if (hcrx->ccid3hcrx_p > p_prev) {
1075 ccid3_hc_rx_send_feedback(sk);
1080 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1082 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1084 ccid3_pr_debug("entry\n");
1086 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1087 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1088 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1089 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1090 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1091 hcrx->ccid3hcrx_s = 0;
1092 hcrx->ccid3hcrx_rtt = 0;
1096 static void ccid3_hc_rx_exit(struct sock *sk)
1098 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1100 BUG_ON(hcrx == NULL);
1102 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1104 /* Empty packet history */
1105 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1107 /* Empty loss interval history */
1108 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1111 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1113 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1115 /* Listen socks doesn't have a private CCID block */
1116 if (sk->sk_state == DCCP_LISTEN)
1119 BUG_ON(hcrx == NULL);
1121 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1122 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1123 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1126 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1128 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1130 /* Listen socks doesn't have a private CCID block */
1131 if (sk->sk_state == DCCP_LISTEN)
1134 BUG_ON(hctx == NULL);
1136 info->tcpi_rto = hctx->ccid3hctx_t_rto;
1137 info->tcpi_rtt = hctx->ccid3hctx_rtt;
1140 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1141 u32 __user *optval, int __user *optlen)
1143 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1146 /* Listen socks doesn't have a private CCID block */
1147 if (sk->sk_state == DCCP_LISTEN)
1151 case DCCP_SOCKOPT_CCID_RX_INFO:
1152 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1154 len = sizeof(hcrx->ccid3hcrx_tfrc);
1155 val = &hcrx->ccid3hcrx_tfrc;
1158 return -ENOPROTOOPT;
1161 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1167 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1168 u32 __user *optval, int __user *optlen)
1170 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1173 /* Listen socks doesn't have a private CCID block */
1174 if (sk->sk_state == DCCP_LISTEN)
1178 case DCCP_SOCKOPT_CCID_TX_INFO:
1179 if (len < sizeof(hctx->ccid3hctx_tfrc))
1181 len = sizeof(hctx->ccid3hctx_tfrc);
1182 val = &hctx->ccid3hctx_tfrc;
1185 return -ENOPROTOOPT;
1188 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1194 static struct ccid_operations ccid3 = {
1195 .ccid_id = DCCPC_CCID3,
1196 .ccid_name = "ccid3",
1197 .ccid_owner = THIS_MODULE,
1198 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1199 .ccid_hc_tx_init = ccid3_hc_tx_init,
1200 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1201 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1202 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1203 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1204 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1205 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1206 .ccid_hc_rx_init = ccid3_hc_rx_init,
1207 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1208 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1209 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1210 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1211 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1212 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1213 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1216 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1217 module_param(ccid3_debug, int, 0444);
1218 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1221 static __init int ccid3_module_init(void)
1225 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1226 if (ccid3_rx_hist == NULL)
1229 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1230 if (ccid3_tx_hist == NULL)
1233 ccid3_li_hist = dccp_li_hist_new("ccid3");
1234 if (ccid3_li_hist == NULL)
1237 rc = ccid_register(&ccid3);
1239 goto out_free_loss_interval_history;
1243 out_free_loss_interval_history:
1244 dccp_li_hist_delete(ccid3_li_hist);
1245 ccid3_li_hist = NULL;
1247 dccp_tx_hist_delete(ccid3_tx_hist);
1248 ccid3_tx_hist = NULL;
1250 dccp_rx_hist_delete(ccid3_rx_hist);
1251 ccid3_rx_hist = NULL;
1254 module_init(ccid3_module_init);
1256 static __exit void ccid3_module_exit(void)
1258 ccid_unregister(&ccid3);
1260 if (ccid3_tx_hist != NULL) {
1261 dccp_tx_hist_delete(ccid3_tx_hist);
1262 ccid3_tx_hist = NULL;
1264 if (ccid3_rx_hist != NULL) {
1265 dccp_rx_hist_delete(ccid3_rx_hist);
1266 ccid3_rx_hist = NULL;
1268 if (ccid3_li_hist != NULL) {
1269 dccp_li_hist_delete(ccid3_li_hist);
1270 ccid3_li_hist = NULL;
1273 module_exit(ccid3_module_exit);
1275 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1276 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1277 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1278 MODULE_LICENSE("GPL");
1279 MODULE_ALIAS("net-dccp-ccid-3");