2 * net/dccp/ccids/ccid3.c
4 * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
5 * Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
7 * An implementation of the DCCP protocol
9 * This code has been developed by the University of Waikato WAND
10 * research group. For further information please see http://www.wand.net.nz/
12 * This code also uses code from Lulea University, rereleased as GPL by its
14 * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
16 * Changes to meet Linux coding standards, to make it meet latest ccid3 draft
17 * and to make it work as a loadable module in the DCCP stack written by
18 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
20 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
22 * This program is free software; you can redistribute it and/or modify
23 * it under the terms of the GNU General Public License as published by
24 * the Free Software Foundation; either version 2 of the License, or
25 * (at your option) any later version.
27 * This program is distributed in the hope that it will be useful,
28 * but WITHOUT ANY WARRANTY; without even the implied warranty of
29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
30 * GNU General Public License for more details.
32 * You should have received a copy of the GNU General Public License
33 * along with this program; if not, write to the Free Software
34 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
38 #include "lib/packet_history.h"
39 #include "lib/loss_interval.h"
43 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
44 static int ccid3_debug;
45 #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
47 #define ccid3_pr_debug(format, a...)
50 static struct dccp_tx_hist *ccid3_tx_hist;
51 static struct dccp_rx_hist *ccid3_rx_hist;
52 static struct dccp_li_hist *ccid3_li_hist;
55 * Transmitter Half-Connection Routines
57 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
58 static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
60 static char *ccid3_state_names[] = {
61 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
62 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
63 [TFRC_SSTATE_FBACK] = "FBACK",
64 [TFRC_SSTATE_TERM] = "TERM",
67 return ccid3_state_names[state];
71 static void ccid3_hc_tx_set_state(struct sock *sk,
72 enum ccid3_hc_tx_states state)
74 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
75 enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
77 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
78 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
79 ccid3_tx_state_name(state));
80 WARN_ON(state == oldstate);
81 hctx->ccid3hctx_state = state;
85 * Recalculate scheduled nominal send time t_nom, inter-packet interval
86 * t_ipi, and delta value. Should be called after each change to X.
88 static inline void ccid3_update_send_time(struct ccid3_hc_tx_sock *hctx)
90 timeval_sub_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
92 /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
93 hctx->ccid3hctx_t_ipi = scaled_div(hctx->ccid3hctx_s,
94 hctx->ccid3hctx_x >> 6);
96 /* Update nominal send time with regard to the new t_ipi */
97 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
99 /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
100 hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
101 TFRC_OPSYS_HALF_TIME_GRAN);
103 ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%llu\n",
104 hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta,
105 hctx->ccid3hctx_s, hctx->ccid3hctx_x >> 6);
111 * X_calc = calcX(s, R, p);
112 * X = max(min(X_calc, 2 * X_recv), s / t_mbi);
114 * If (now - tld >= R)
115 * X = max(min(2 * X, 2 * X_recv), s / R);
118 * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
119 * fine-grained resolution of sending rates. This requires scaling by 2^6
120 * throughout the code. Only X_calc is unscaled (in bytes/second).
122 * If X has changed, we also update the scheduled send time t_now,
123 * the inter-packet interval t_ipi, and the delta value.
125 static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
128 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
129 const __u64 old_x = hctx->ccid3hctx_x;
131 if (hctx->ccid3hctx_p > 0) {
133 hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
134 hctx->ccid3hctx_x_recv * 2);
135 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
136 (((__u64)hctx->ccid3hctx_s) << 6) /
139 } else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) -
140 (suseconds_t)hctx->ccid3hctx_rtt >= 0) {
143 max(2 * min(hctx->ccid3hctx_x, hctx->ccid3hctx_x_recv),
144 scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
145 hctx->ccid3hctx_rtt));
146 hctx->ccid3hctx_t_ld = *now;
149 if (hctx->ccid3hctx_x != old_x) {
150 ccid3_pr_debug("X_prev=%llu, X_now=%llu, X_calc=%u, "
151 "X_recv=%llu\n", old_x >> 6, hctx->ccid3hctx_x >> 6,
152 hctx->ccid3hctx_x_calc, hctx->ccid3hctx_x_recv >> 6);
154 ccid3_update_send_time(hctx);
159 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
160 * @len: DCCP packet payload size in bytes
162 static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
164 hctx->ccid3hctx_s = hctx->ccid3hctx_s == 0 ? len :
165 (9 * hctx->ccid3hctx_s + len) / 10;
167 * Note: We could do a potential optimisation here - when `s' changes,
168 * recalculate sending rate and consequently t_ipi, t_delta, and
169 * t_now. This is however non-standard, and the benefits are not
170 * clear, so it is currently left out.
175 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
176 * The algorithm is not applicable if RTT < 4 microseconds.
178 static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
184 if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */
187 delta = timeval_delta(now, &hctx->ccid3hctx_t_last_win_count);
188 DCCP_BUG_ON(delta < 0);
190 quarter_rtts = (u32)delta / (hctx->ccid3hctx_rtt / 4);
192 if (quarter_rtts > 0) {
193 hctx->ccid3hctx_t_last_win_count = *now;
194 hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5);
195 hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
197 ccid3_pr_debug("now at %#X\n", hctx->ccid3hctx_last_win_count);
201 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
203 struct sock *sk = (struct sock *)data;
204 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
205 unsigned long t_nfb = USEC_PER_SEC / 5;
208 if (sock_owned_by_user(sk)) {
209 /* Try again later. */
210 /* XXX: set some sensible MIB */
214 ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
215 ccid3_tx_state_name(hctx->ccid3hctx_state));
217 switch (hctx->ccid3hctx_state) {
218 case TFRC_SSTATE_NO_FBACK:
219 /* RFC 3448, 4.4: Halve send rate directly */
220 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
221 (((__u64)hctx->ccid3hctx_s) << 6) /
224 ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u "
225 "bytes/s\n", dccp_role(sk), sk,
226 ccid3_tx_state_name(hctx->ccid3hctx_state),
227 (unsigned)(hctx->ccid3hctx_x >> 6));
228 /* The value of R is still undefined and so we can not recompute
229 * the timout value. Keep initial value as per [RFC 4342, 5]. */
230 t_nfb = TFRC_INITIAL_TIMEOUT;
231 ccid3_update_send_time(hctx);
233 case TFRC_SSTATE_FBACK:
235 * Check if IDLE since last timeout and recv rate is less than
236 * 4 packets (in units of 64*bytes/sec) per RTT
238 if (!hctx->ccid3hctx_idle ||
239 (hctx->ccid3hctx_x_recv >= 4 *
240 scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
241 hctx->ccid3hctx_rtt))) {
244 ccid3_pr_debug("%s(%p, state=%s), not idle\n",
246 ccid3_tx_state_name(hctx->ccid3hctx_state));
249 * Modify the cached value of X_recv [RFC 3448, 4.4]
251 * If (p == 0 || X_calc > 2 * X_recv)
252 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
254 * X_recv = X_calc / 4;
256 * Note that X_recv is scaled by 2^6 while X_calc is not
258 BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
260 if (hctx->ccid3hctx_p == 0 ||
261 (hctx->ccid3hctx_x_calc >
262 (hctx->ccid3hctx_x_recv >> 5))) {
264 hctx->ccid3hctx_x_recv =
265 max(hctx->ccid3hctx_x_recv / 2,
266 (((__u64)hctx->ccid3hctx_s) << 6) /
269 if (hctx->ccid3hctx_p == 0)
270 dccp_timestamp(sk, &now);
272 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
273 hctx->ccid3hctx_x_recv <<= 4;
275 /* Now recalculate X [RFC 3448, 4.3, step (4)] */
276 ccid3_hc_tx_update_x(sk, &now);
279 * Schedule no feedback timer to expire in
280 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
281 * See comments in packet_recv() regarding the value of t_RTO.
283 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
285 case TFRC_SSTATE_NO_SENT:
286 DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk);
288 case TFRC_SSTATE_TERM:
292 hctx->ccid3hctx_idle = 1;
295 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
296 jiffies + usecs_to_jiffies(t_nfb));
304 * > 0: delay (in msecs) that should pass before actually sending
305 * = 0: can send immediately
306 * < 0: error condition; do not send packet
308 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
310 struct dccp_sock *dp = dccp_sk(sk);
311 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
315 BUG_ON(hctx == NULL);
318 * This function is called only for Data and DataAck packets. Sending
319 * zero-sized Data(Ack)s is theoretically possible, but for congestion
320 * control this case is pathological - ignore it.
322 if (unlikely(skb->len == 0))
325 dccp_timestamp(sk, &now);
327 switch (hctx->ccid3hctx_state) {
328 case TFRC_SSTATE_NO_SENT:
329 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
331 usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
332 hctx->ccid3hctx_last_win_count = 0;
333 hctx->ccid3hctx_t_last_win_count = now;
334 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
336 /* Set initial sending rate X/s to 1pps (X is scaled by 2^6) */
337 ccid3_hc_tx_update_s(hctx, skb->len);
338 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
339 hctx->ccid3hctx_x <<= 6;
341 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
342 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
343 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
344 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
346 /* Set t_0 for initial packet */
347 hctx->ccid3hctx_t_nom = now;
349 case TFRC_SSTATE_NO_FBACK:
350 case TFRC_SSTATE_FBACK:
351 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
352 ccid3_pr_debug("delay=%ld\n", (long)delay);
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("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
371 /* prepare to send now (add options etc.) */
372 dp->dccps_hc_tx_insert_options = 1;
373 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
375 /* set the nominal send time for the next following packet */
376 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
381 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
384 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
386 struct dccp_tx_hist_entry *packet;
388 BUG_ON(hctx == NULL);
390 ccid3_hc_tx_update_s(hctx, len);
392 packet = dccp_tx_hist_entry_new(ccid3_tx_hist, GFP_ATOMIC);
393 if (unlikely(packet == NULL)) {
394 DCCP_CRIT("packet history - out of memory!");
397 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
399 dccp_timestamp(sk, &now);
400 packet->dccphtx_tstamp = now;
401 packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
402 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
403 packet->dccphtx_sent = 1;
404 hctx->ccid3hctx_idle = 0;
407 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
409 const struct dccp_sock *dp = dccp_sk(sk);
410 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
411 struct ccid3_options_received *opt_recv;
412 struct dccp_tx_hist_entry *packet;
416 suseconds_t r_sample, t_elapsed;
418 BUG_ON(hctx == NULL);
420 /* we are only interested in ACKs */
421 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
422 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
425 opt_recv = &hctx->ccid3hctx_options_received;
427 switch (hctx->ccid3hctx_state) {
428 case TFRC_SSTATE_NO_FBACK:
429 case TFRC_SSTATE_FBACK:
430 /* get packet from history to look up t_recvdata */
431 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
432 DCCP_SKB_CB(skb)->dccpd_ack_seq);
433 if (unlikely(packet == NULL)) {
434 DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
435 "in history!\n", dccp_role(sk), sk,
436 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
437 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
441 /* Update receive rate in units of 64 * bytes/second */
442 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
443 hctx->ccid3hctx_x_recv <<= 6;
445 /* Update loss event rate */
446 pinv = opt_recv->ccid3or_loss_event_rate;
447 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
448 hctx->ccid3hctx_p = 0;
449 else /* can not exceed 100% */
450 hctx->ccid3hctx_p = 1000000 / pinv;
452 dccp_timestamp(sk, &now);
455 * Calculate new round trip sample as per [RFC 3448, 4.3] by
456 * R_sample = (now - t_recvdata) - t_elapsed
458 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
459 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
461 DCCP_BUG_ON(r_sample < 0);
462 if (unlikely(r_sample <= t_elapsed))
463 DCCP_WARN("WARNING: r_sample=%dus <= t_elapsed=%dus\n",
464 (int)r_sample, (int)t_elapsed);
466 r_sample -= t_elapsed;
467 CCID3_RTT_SANITY_CHECK(r_sample);
469 /* Update RTT estimate by
470 * If (No feedback recv)
473 * R = q * R + (1 - q) * R_sample;
475 * q is a constant, RFC 3448 recomments 0.9
477 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
479 * Larger Initial Windows [RFC 4342, sec. 5]
481 __u32 w_init = min(4 * dp->dccps_mss_cache,
482 max(2 * dp->dccps_mss_cache, 4380U));
483 hctx->ccid3hctx_rtt = r_sample;
484 hctx->ccid3hctx_x = scaled_div(w_init << 6, r_sample);
485 hctx->ccid3hctx_t_ld = now;
487 ccid3_update_send_time(hctx);
489 ccid3_pr_debug("%s(%p), s=%u, MSS=%u, w_init=%u, "
490 "R_sample=%dus, X=%u\n", dccp_role(sk),
491 sk, hctx->ccid3hctx_s,
495 (unsigned)(hctx->ccid3hctx_x >> 6));
497 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
499 hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
502 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
503 if (hctx->ccid3hctx_p > 0)
504 hctx->ccid3hctx_x_calc =
505 tfrc_calc_x(hctx->ccid3hctx_s,
508 ccid3_hc_tx_update_x(sk, &now);
510 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%dus), s=%u, "
511 "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
513 sk, hctx->ccid3hctx_rtt, (int)r_sample,
514 hctx->ccid3hctx_s, hctx->ccid3hctx_p,
515 hctx->ccid3hctx_x_calc,
516 (unsigned)(hctx->ccid3hctx_x_recv >> 6),
517 (unsigned)(hctx->ccid3hctx_x >> 6));
520 /* unschedule no feedback timer */
521 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
523 /* remove all packets older than the one acked from history */
524 dccp_tx_hist_purge_older(ccid3_tx_hist,
525 &hctx->ccid3hctx_hist, packet);
527 * As we have calculated new ipi, delta, t_nom it is possible
528 * that we now can send a packet, so wake up dccp_wait_for_ccid
530 sk->sk_write_space(sk);
533 * Update timeout interval for the nofeedback timer.
534 * We use a configuration option to increase the lower bound.
535 * This can help avoid triggering the nofeedback timer too
536 * often ('spinning') on LANs with small RTTs.
538 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
539 CONFIG_IP_DCCP_CCID3_RTO *
540 (USEC_PER_SEC/1000));
542 * Schedule no feedback timer to expire in
543 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
545 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
547 ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
548 "expire in %lu jiffies (%luus)\n",
550 sk, usecs_to_jiffies(t_nfb), t_nfb);
552 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
553 jiffies + usecs_to_jiffies(t_nfb));
556 hctx->ccid3hctx_idle = 1;
558 case TFRC_SSTATE_NO_SENT: /* fall through */
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(%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 =
594 ntohl(*(__be32 *)value);
595 ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
597 opt_recv->ccid3or_loss_event_rate);
600 case TFRC_OPT_LOSS_INTERVALS:
601 opt_recv->ccid3or_loss_intervals_idx = idx;
602 opt_recv->ccid3or_loss_intervals_len = len;
603 ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
605 opt_recv->ccid3or_loss_intervals_idx,
606 opt_recv->ccid3or_loss_intervals_len);
608 case TFRC_OPT_RECEIVE_RATE:
609 if (unlikely(len != 4)) {
610 DCCP_WARN("%s(%p), invalid len %d "
611 "for TFRC_OPT_RECEIVE_RATE\n",
612 dccp_role(sk), sk, len);
615 opt_recv->ccid3or_receive_rate =
616 ntohl(*(__be32 *)value);
617 ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
619 opt_recv->ccid3or_receive_rate);
627 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
629 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
631 hctx->ccid3hctx_s = 0;
632 hctx->ccid3hctx_rtt = 0;
633 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
634 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
636 hctx->ccid3hctx_no_feedback_timer.function =
637 ccid3_hc_tx_no_feedback_timer;
638 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
639 init_timer(&hctx->ccid3hctx_no_feedback_timer);
644 static void ccid3_hc_tx_exit(struct sock *sk)
646 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
648 BUG_ON(hctx == NULL);
650 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
651 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
653 /* Empty packet history */
654 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
657 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
659 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
661 /* Listen socks doesn't have a private CCID block */
662 if (sk->sk_state == DCCP_LISTEN)
665 BUG_ON(hctx == NULL);
667 info->tcpi_rto = hctx->ccid3hctx_t_rto;
668 info->tcpi_rtt = hctx->ccid3hctx_rtt;
671 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
672 u32 __user *optval, int __user *optlen)
674 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
677 /* Listen socks doesn't have a private CCID block */
678 if (sk->sk_state == DCCP_LISTEN)
682 case DCCP_SOCKOPT_CCID_TX_INFO:
683 if (len < sizeof(hctx->ccid3hctx_tfrc))
685 len = sizeof(hctx->ccid3hctx_tfrc);
686 val = &hctx->ccid3hctx_tfrc;
692 if (put_user(len, optlen) || copy_to_user(optval, val, len))
699 * Receiver Half-Connection Routines
701 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
702 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
704 static char *ccid3_rx_state_names[] = {
705 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
706 [TFRC_RSTATE_DATA] = "DATA",
707 [TFRC_RSTATE_TERM] = "TERM",
710 return ccid3_rx_state_names[state];
714 static void ccid3_hc_rx_set_state(struct sock *sk,
715 enum ccid3_hc_rx_states state)
717 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
718 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
720 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
721 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
722 ccid3_rx_state_name(state));
723 WARN_ON(state == oldstate);
724 hcrx->ccid3hcrx_state = state;
727 static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
729 if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
730 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
732 hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
733 (9 * hcrx->ccid3hcrx_s + len) / 10;
736 static void ccid3_hc_rx_send_feedback(struct sock *sk)
738 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
739 struct dccp_sock *dp = dccp_sk(sk);
740 struct dccp_rx_hist_entry *packet;
744 ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk);
746 dccp_timestamp(sk, &now);
748 switch (hcrx->ccid3hcrx_state) {
749 case TFRC_RSTATE_NO_DATA:
750 hcrx->ccid3hcrx_x_recv = 0;
752 case TFRC_RSTATE_DATA:
753 delta = timeval_delta(&now,
754 &hcrx->ccid3hcrx_tstamp_last_feedback);
755 DCCP_BUG_ON(delta < 0);
756 hcrx->ccid3hcrx_x_recv =
757 scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
759 case TFRC_RSTATE_TERM:
760 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
764 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
765 if (unlikely(packet == NULL)) {
766 DCCP_WARN("%s(%p), no data packet in history!\n",
771 hcrx->ccid3hcrx_tstamp_last_feedback = now;
772 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
773 hcrx->ccid3hcrx_bytes_recv = 0;
775 /* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
776 delta = timeval_delta(&now, &packet->dccphrx_tstamp);
777 DCCP_BUG_ON(delta < 0);
778 hcrx->ccid3hcrx_elapsed_time = delta / 10;
780 if (hcrx->ccid3hcrx_p == 0)
781 hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
782 else if (hcrx->ccid3hcrx_p > 1000000) {
783 DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
784 hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
786 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
788 dp->dccps_hc_rx_insert_options = 1;
792 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
794 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
797 BUG_ON(hcrx == NULL);
799 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
802 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
804 if (dccp_packet_without_ack(skb))
807 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
808 pinv = htonl(hcrx->ccid3hcrx_pinv);
810 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
811 dccp_insert_option_elapsed_time(sk, skb,
812 hcrx->ccid3hcrx_elapsed_time)) ||
813 dccp_insert_option_timestamp(sk, skb) ||
814 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
815 &pinv, sizeof(pinv)) ||
816 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
817 &x_recv, sizeof(x_recv)))
823 /* calculate first loss interval
825 * returns estimated loss interval in usecs */
827 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
829 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
830 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
832 suseconds_t rtt, delta;
833 struct timeval tstamp = { 0, };
839 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
841 if (dccp_rx_hist_entry_data_packet(entry)) {
846 tstamp = entry->dccphrx_tstamp;
847 win_count = entry->dccphrx_ccval;
851 interval = win_count - entry->dccphrx_ccval;
853 interval += TFRC_WIN_COUNT_LIMIT;
861 if (unlikely(step == 0)) {
862 DCCP_WARN("%s(%p), packet history has no data packets!\n",
867 if (unlikely(interval == 0)) {
868 DCCP_WARN("%s(%p), Could not find a win_count interval > 0."
869 "Defaulting to 1\n", dccp_role(sk), sk);
874 DCCP_CRIT("tail is null\n");
878 delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
879 DCCP_BUG_ON(delta < 0);
881 rtt = delta * 4 / interval;
882 ccid3_pr_debug("%s(%p), approximated RTT to %dus\n",
883 dccp_role(sk), sk, (int)rtt);
886 * Determine the length of the first loss interval via inverse lookup.
887 * Assume that X_recv can be computed by the throughput equation
891 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
893 if (rtt == 0) { /* would result in divide-by-zero */
894 DCCP_WARN("RTT==0\n");
898 dccp_timestamp(sk, &tstamp);
899 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
900 DCCP_BUG_ON(delta <= 0);
902 x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
903 if (x_recv == 0) { /* would also trigger divide-by-zero */
904 DCCP_WARN("X_recv==0\n");
905 if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
906 DCCP_BUG("stored value of X_recv is zero");
911 fval = scaled_div(hcrx->ccid3hcrx_s, rtt);
912 fval = scaled_div32(fval, x_recv);
913 p = tfrc_calc_x_reverse_lookup(fval);
915 ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
916 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
924 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
926 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
927 struct dccp_li_hist_entry *head;
930 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
931 if (!dccp_li_hist_interval_new(ccid3_li_hist,
932 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
935 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
936 struct dccp_li_hist_entry, dccplih_node);
937 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
939 struct dccp_li_hist_entry *entry;
940 struct list_head *tail;
942 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
943 struct dccp_li_hist_entry, dccplih_node);
944 /* FIXME win count check removed as was wrong */
945 /* should make this check with receive history */
946 /* and compare there as per section 10.2 of RFC4342 */
948 /* new loss event detected */
949 /* calculate last interval length */
950 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
951 entry = dccp_li_hist_entry_new(ccid3_li_hist, GFP_ATOMIC);
954 DCCP_BUG("out of memory - can not allocate entry");
958 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
960 tail = hcrx->ccid3hcrx_li_hist.prev;
962 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
964 /* Create the newest interval */
965 entry->dccplih_seqno = seq_loss;
966 entry->dccplih_interval = seq_temp;
967 entry->dccplih_win_count = win_loss;
971 static int ccid3_hc_rx_detect_loss(struct sock *sk,
972 struct dccp_rx_hist_entry *packet)
974 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
975 struct dccp_rx_hist_entry *rx_hist =
976 dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
977 u64 seqno = packet->dccphrx_seqno;
983 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
986 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
987 hcrx->ccid3hcrx_seqno_nonloss = seqno;
988 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
993 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
994 > TFRC_RECV_NUM_LATE_LOSS) {
996 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
997 hcrx->ccid3hcrx_ccval_nonloss);
998 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
999 dccp_inc_seqno(&tmp_seqno);
1000 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
1001 dccp_inc_seqno(&tmp_seqno);
1002 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
1003 tmp_seqno, &ccval)) {
1004 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
1005 hcrx->ccid3hcrx_ccval_nonloss = ccval;
1006 dccp_inc_seqno(&tmp_seqno);
1010 /* FIXME - this code could be simplified with above while */
1011 /* but works at moment */
1012 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
1013 hcrx->ccid3hcrx_seqno_nonloss = seqno;
1014 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
1018 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
1019 &hcrx->ccid3hcrx_li_hist, packet,
1020 hcrx->ccid3hcrx_seqno_nonloss);
1024 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
1026 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1027 const struct dccp_options_received *opt_recv;
1028 struct dccp_rx_hist_entry *packet;
1030 u32 p_prev, rtt_prev;
1031 suseconds_t r_sample, t_elapsed;
1032 int loss, payload_size;
1034 BUG_ON(hcrx == NULL);
1036 opt_recv = &dccp_sk(sk)->dccps_options_received;
1038 switch (DCCP_SKB_CB(skb)->dccpd_type) {
1040 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1042 case DCCP_PKT_DATAACK:
1043 if (opt_recv->dccpor_timestamp_echo == 0)
1045 rtt_prev = hcrx->ccid3hcrx_rtt;
1046 dccp_timestamp(sk, &now);
1047 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
1048 r_sample = timeval_usecs(&now);
1049 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
1051 DCCP_BUG_ON(r_sample < 0);
1052 if (unlikely(r_sample <= t_elapsed))
1053 DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
1054 (long)r_sample, (long)t_elapsed);
1056 r_sample -= t_elapsed;
1057 CCID3_RTT_SANITY_CHECK(r_sample);
1059 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1060 hcrx->ccid3hcrx_rtt = r_sample;
1062 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
1065 if (rtt_prev != hcrx->ccid3hcrx_rtt)
1066 ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n",
1067 dccp_role(sk), sk, hcrx->ccid3hcrx_rtt,
1068 opt_recv->dccpor_elapsed_time);
1072 default: /* We're not interested in other packet types, move along */
1076 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
1078 if (unlikely(packet == NULL)) {
1079 DCCP_WARN("%s(%p), Not enough mem to add rx packet "
1080 "to history, consider it lost!\n", dccp_role(sk), sk);
1084 loss = ccid3_hc_rx_detect_loss(sk, packet);
1086 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1089 payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
1090 ccid3_hc_rx_update_s(hcrx, payload_size);
1092 switch (hcrx->ccid3hcrx_state) {
1093 case TFRC_RSTATE_NO_DATA:
1094 ccid3_pr_debug("%s(%p, state=%s), skb=%p, sending initial "
1095 "feedback\n", dccp_role(sk), sk,
1096 dccp_state_name(sk->sk_state), skb);
1097 ccid3_hc_rx_send_feedback(sk);
1098 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1100 case TFRC_RSTATE_DATA:
1101 hcrx->ccid3hcrx_bytes_recv += payload_size;
1105 dccp_timestamp(sk, &now);
1106 if ((timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
1107 (suseconds_t)hcrx->ccid3hcrx_rtt) >= 0) {
1108 hcrx->ccid3hcrx_tstamp_last_ack = now;
1109 ccid3_hc_rx_send_feedback(sk);
1112 case TFRC_RSTATE_TERM:
1113 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
1117 /* Dealing with packet loss */
1118 ccid3_pr_debug("%s(%p, state=%s), data loss! Reacting...\n",
1119 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1121 p_prev = hcrx->ccid3hcrx_p;
1123 /* Calculate loss event rate */
1124 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1125 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1127 /* Scaling up by 1000000 as fixed decimal */
1129 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1131 DCCP_BUG("empty loss history");
1133 if (hcrx->ccid3hcrx_p > p_prev) {
1134 ccid3_hc_rx_send_feedback(sk);
1139 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1141 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1143 ccid3_pr_debug("entry\n");
1145 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1146 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1147 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1148 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1149 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1150 hcrx->ccid3hcrx_s = 0;
1151 hcrx->ccid3hcrx_rtt = 0;
1155 static void ccid3_hc_rx_exit(struct sock *sk)
1157 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1159 BUG_ON(hcrx == NULL);
1161 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1163 /* Empty packet history */
1164 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1166 /* Empty loss interval history */
1167 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1170 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1172 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1174 /* Listen socks doesn't have a private CCID block */
1175 if (sk->sk_state == DCCP_LISTEN)
1178 BUG_ON(hcrx == NULL);
1180 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1181 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1182 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1185 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1186 u32 __user *optval, int __user *optlen)
1188 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1191 /* Listen socks doesn't have a private CCID block */
1192 if (sk->sk_state == DCCP_LISTEN)
1196 case DCCP_SOCKOPT_CCID_RX_INFO:
1197 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1199 len = sizeof(hcrx->ccid3hcrx_tfrc);
1200 val = &hcrx->ccid3hcrx_tfrc;
1203 return -ENOPROTOOPT;
1206 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1212 static struct ccid_operations ccid3 = {
1213 .ccid_id = DCCPC_CCID3,
1214 .ccid_name = "ccid3",
1215 .ccid_owner = THIS_MODULE,
1216 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1217 .ccid_hc_tx_init = ccid3_hc_tx_init,
1218 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1219 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1220 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1221 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1222 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1223 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1224 .ccid_hc_rx_init = ccid3_hc_rx_init,
1225 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1226 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1227 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1228 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1229 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1230 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1231 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1234 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1235 module_param(ccid3_debug, int, 0444);
1236 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1239 static __init int ccid3_module_init(void)
1243 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1244 if (ccid3_rx_hist == NULL)
1247 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1248 if (ccid3_tx_hist == NULL)
1251 ccid3_li_hist = dccp_li_hist_new("ccid3");
1252 if (ccid3_li_hist == NULL)
1255 rc = ccid_register(&ccid3);
1257 goto out_free_loss_interval_history;
1261 out_free_loss_interval_history:
1262 dccp_li_hist_delete(ccid3_li_hist);
1263 ccid3_li_hist = NULL;
1265 dccp_tx_hist_delete(ccid3_tx_hist);
1266 ccid3_tx_hist = NULL;
1268 dccp_rx_hist_delete(ccid3_rx_hist);
1269 ccid3_rx_hist = NULL;
1272 module_init(ccid3_module_init);
1274 static __exit void ccid3_module_exit(void)
1276 ccid_unregister(&ccid3);
1278 if (ccid3_tx_hist != NULL) {
1279 dccp_tx_hist_delete(ccid3_tx_hist);
1280 ccid3_tx_hist = NULL;
1282 if (ccid3_rx_hist != NULL) {
1283 dccp_rx_hist_delete(ccid3_rx_hist);
1284 ccid3_rx_hist = NULL;
1286 if (ccid3_li_hist != NULL) {
1287 dccp_li_hist_delete(ccid3_li_hist);
1288 ccid3_li_hist = NULL;
1291 module_exit(ccid3_module_exit);
1293 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1294 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1295 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1296 MODULE_LICENSE("GPL");
1297 MODULE_ALIAS("net-dccp-ccid-3");