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);
106 * X_calc = calcX(s, R, p);
107 * X = max(min(X_calc, 2 * X_recv), s / t_mbi);
109 * If (now - tld >= R)
110 * X = max(min(2 * X, 2 * X_recv), s / R);
113 * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
114 * fine-grained resolution of sending rates. This requires scaling by 2^6
115 * throughout the code. Only X_calc is unscaled (in bytes/second).
117 * If X has changed, we also update the scheduled send time t_now,
118 * the inter-packet interval t_ipi, and the delta value.
120 static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
123 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
124 const __u64 old_x = hctx->ccid3hctx_x;
126 if (hctx->ccid3hctx_p > 0) {
128 hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
129 hctx->ccid3hctx_x_recv * 2);
130 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
131 (((__u64)hctx->ccid3hctx_s) << 6) /
134 } else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) -
135 (suseconds_t)hctx->ccid3hctx_rtt >= 0) {
138 max(2 * min(hctx->ccid3hctx_x, hctx->ccid3hctx_x_recv),
139 scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
140 hctx->ccid3hctx_rtt));
141 hctx->ccid3hctx_t_ld = *now;
144 if (hctx->ccid3hctx_x != old_x)
145 ccid3_update_send_time(hctx);
149 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
150 * @len: DCCP packet payload size in bytes
152 static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
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(%p, state=%s) - entry \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(hctx->ccid3hctx_x / 2,
211 (((__u64)hctx->ccid3hctx_s) << 6) /
214 ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u "
215 "bytes/s\n", dccp_role(sk), sk,
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(((__u64)hctx->ccid3hctx_s) << 6,
231 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 >
252 (hctx->ccid3hctx_x_recv >> 5))) {
254 hctx->ccid3hctx_x_recv =
255 max(hctx->ccid3hctx_x_recv / 2,
256 (((__u64)hctx->ccid3hctx_s) << 6) /
259 if (hctx->ccid3hctx_p == 0)
260 dccp_timestamp(sk, &now);
262 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
263 hctx->ccid3hctx_x_recv <<= 4;
265 /* Now recalculate X [RFC 3448, 4.3, step (4)] */
266 ccid3_hc_tx_update_x(sk, &now);
269 * Schedule no feedback timer to expire in
270 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
271 * See comments in packet_recv() regarding the value of t_RTO.
273 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
275 case TFRC_SSTATE_NO_SENT:
276 DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk);
278 case TFRC_SSTATE_TERM:
282 hctx->ccid3hctx_idle = 1;
285 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
286 jiffies + usecs_to_jiffies(t_nfb));
294 * > 0: delay (in msecs) that should pass before actually sending
295 * = 0: can send immediately
296 * < 0: error condition; do not send packet
298 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
300 struct dccp_sock *dp = dccp_sk(sk);
301 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
305 BUG_ON(hctx == NULL);
308 * This function is called only for Data and DataAck packets. Sending
309 * zero-sized Data(Ack)s is theoretically possible, but for congestion
310 * control this case is pathological - ignore it.
312 if (unlikely(skb->len == 0))
315 dccp_timestamp(sk, &now);
317 switch (hctx->ccid3hctx_state) {
318 case TFRC_SSTATE_NO_SENT:
319 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
321 usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
322 hctx->ccid3hctx_last_win_count = 0;
323 hctx->ccid3hctx_t_last_win_count = now;
324 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
326 /* Set initial sending rate X/s to 1pps (X is scaled by 2^6) */
327 ccid3_hc_tx_update_s(hctx, skb->len);
328 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
329 hctx->ccid3hctx_x <<= 6;
331 /* First timeout, according to [RFC 3448, 4.2], is 1 second */
332 hctx->ccid3hctx_t_ipi = USEC_PER_SEC;
333 /* Initial delta: minimum of 0.5 sec and t_gran/2 */
334 hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN;
336 /* Set t_0 for initial packet */
337 hctx->ccid3hctx_t_nom = now;
339 case TFRC_SSTATE_NO_FBACK:
340 case TFRC_SSTATE_FBACK:
341 delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
343 * Scheduling of packet transmissions [RFC 3448, 4.6]
345 * if (t_now > t_nom - delta)
346 * // send the packet now
348 * // send the packet in (t_nom - t_now) milliseconds.
350 if (delay - (suseconds_t)hctx->ccid3hctx_delta >= 0)
351 return delay / 1000L;
353 ccid3_hc_tx_update_win_count(hctx, &now);
355 case TFRC_SSTATE_TERM:
356 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
360 /* prepare to send now (add options etc.) */
361 dp->dccps_hc_tx_insert_options = 1;
362 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
364 /* set the nominal send time for the next following packet */
365 timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
370 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
373 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
375 struct dccp_tx_hist_entry *packet;
377 BUG_ON(hctx == NULL);
379 ccid3_hc_tx_update_s(hctx, len);
381 packet = dccp_tx_hist_entry_new(ccid3_tx_hist, GFP_ATOMIC);
382 if (unlikely(packet == NULL)) {
383 DCCP_CRIT("packet history - out of memory!");
386 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
388 dccp_timestamp(sk, &now);
389 packet->dccphtx_tstamp = now;
390 packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
391 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
392 packet->dccphtx_sent = 1;
393 hctx->ccid3hctx_idle = 0;
396 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
398 const struct dccp_sock *dp = dccp_sk(sk);
399 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
400 struct ccid3_options_received *opt_recv;
401 struct dccp_tx_hist_entry *packet;
405 suseconds_t r_sample, t_elapsed;
407 BUG_ON(hctx == NULL);
409 /* we are only interested in ACKs */
410 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
411 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
414 opt_recv = &hctx->ccid3hctx_options_received;
416 switch (hctx->ccid3hctx_state) {
417 case TFRC_SSTATE_NO_FBACK:
418 case TFRC_SSTATE_FBACK:
419 /* get packet from history to look up t_recvdata */
420 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
421 DCCP_SKB_CB(skb)->dccpd_ack_seq);
422 if (unlikely(packet == NULL)) {
423 DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
424 "in history!\n", dccp_role(sk), sk,
425 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
426 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
430 /* Update receive rate in units of 64 * bytes/second */
431 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
432 hctx->ccid3hctx_x_recv <<= 6;
434 /* Update loss event rate */
435 pinv = opt_recv->ccid3or_loss_event_rate;
436 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
437 hctx->ccid3hctx_p = 0;
438 else /* can not exceed 100% */
439 hctx->ccid3hctx_p = 1000000 / pinv;
441 dccp_timestamp(sk, &now);
444 * Calculate new round trip sample as per [RFC 3448, 4.3] by
445 * R_sample = (now - t_recvdata) - t_elapsed
447 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
448 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
450 DCCP_BUG_ON(r_sample < 0);
451 if (unlikely(r_sample <= t_elapsed))
452 DCCP_WARN("WARNING: r_sample=%dus <= t_elapsed=%dus\n",
453 (int)r_sample, (int)t_elapsed);
455 r_sample -= t_elapsed;
456 CCID3_RTT_SANITY_CHECK(r_sample);
458 /* Update RTT estimate by
459 * If (No feedback recv)
462 * R = q * R + (1 - q) * R_sample;
464 * q is a constant, RFC 3448 recomments 0.9
466 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
468 * Larger Initial Windows [RFC 4342, sec. 5]
470 __u32 w_init = min(4 * dp->dccps_mss_cache,
471 max(2 * dp->dccps_mss_cache, 4380U));
472 hctx->ccid3hctx_rtt = r_sample;
473 hctx->ccid3hctx_x = scaled_div(w_init << 6, r_sample);
474 hctx->ccid3hctx_t_ld = now;
476 ccid3_update_send_time(hctx);
478 ccid3_pr_debug("%s(%p), s=%u, MSS=%u, w_init=%u, "
479 "R_sample=%dus, X=%u\n", dccp_role(sk),
480 sk, hctx->ccid3hctx_s,
484 (unsigned)(hctx->ccid3hctx_x >> 6));
486 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
488 hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
491 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
492 if (hctx->ccid3hctx_p > 0)
493 hctx->ccid3hctx_x_calc =
494 tfrc_calc_x(hctx->ccid3hctx_s,
497 ccid3_hc_tx_update_x(sk, &now);
499 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%dus), s=%u, "
500 "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
502 sk, hctx->ccid3hctx_rtt, (int)r_sample,
503 hctx->ccid3hctx_s, hctx->ccid3hctx_p,
504 hctx->ccid3hctx_x_calc,
505 (unsigned)(hctx->ccid3hctx_x_recv >> 6),
506 (unsigned)(hctx->ccid3hctx_x >> 6));
509 /* unschedule no feedback timer */
510 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
512 /* remove all packets older than the one acked from history */
513 dccp_tx_hist_purge_older(ccid3_tx_hist,
514 &hctx->ccid3hctx_hist, packet);
516 * As we have calculated new ipi, delta, t_nom it is possible
517 * that we now can send a packet, so wake up dccp_wait_for_ccid
519 sk->sk_write_space(sk);
522 * Update timeout interval for the nofeedback timer.
523 * We use a configuration option to increase the lower bound.
524 * This can help avoid triggering the nofeedback timer too
525 * often ('spinning') on LANs with small RTTs.
527 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
528 CONFIG_IP_DCCP_CCID3_RTO *
529 (USEC_PER_SEC/1000));
531 * Schedule no feedback timer to expire in
532 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
534 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
536 ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
537 "expire in %lu jiffies (%luus)\n",
539 sk, usecs_to_jiffies(t_nfb), t_nfb);
541 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
542 jiffies + usecs_to_jiffies(t_nfb));
545 hctx->ccid3hctx_idle = 1;
547 case TFRC_SSTATE_NO_SENT: /* fall through */
548 case TFRC_SSTATE_TERM: /* ignore feedback when closing */
553 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
554 unsigned char len, u16 idx,
555 unsigned char *value)
558 const struct dccp_sock *dp = dccp_sk(sk);
559 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
560 struct ccid3_options_received *opt_recv;
562 BUG_ON(hctx == NULL);
564 opt_recv = &hctx->ccid3hctx_options_received;
566 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
567 opt_recv->ccid3or_seqno = dp->dccps_gsr;
568 opt_recv->ccid3or_loss_event_rate = ~0;
569 opt_recv->ccid3or_loss_intervals_idx = 0;
570 opt_recv->ccid3or_loss_intervals_len = 0;
571 opt_recv->ccid3or_receive_rate = 0;
575 case TFRC_OPT_LOSS_EVENT_RATE:
576 if (unlikely(len != 4)) {
577 DCCP_WARN("%s(%p), invalid len %d "
578 "for TFRC_OPT_LOSS_EVENT_RATE\n",
579 dccp_role(sk), sk, len);
582 opt_recv->ccid3or_loss_event_rate =
583 ntohl(*(__be32 *)value);
584 ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
586 opt_recv->ccid3or_loss_event_rate);
589 case TFRC_OPT_LOSS_INTERVALS:
590 opt_recv->ccid3or_loss_intervals_idx = idx;
591 opt_recv->ccid3or_loss_intervals_len = len;
592 ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
594 opt_recv->ccid3or_loss_intervals_idx,
595 opt_recv->ccid3or_loss_intervals_len);
597 case TFRC_OPT_RECEIVE_RATE:
598 if (unlikely(len != 4)) {
599 DCCP_WARN("%s(%p), invalid len %d "
600 "for TFRC_OPT_RECEIVE_RATE\n",
601 dccp_role(sk), sk, len);
604 opt_recv->ccid3or_receive_rate =
605 ntohl(*(__be32 *)value);
606 ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
608 opt_recv->ccid3or_receive_rate);
616 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
618 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
620 hctx->ccid3hctx_s = 0;
621 hctx->ccid3hctx_rtt = 0;
622 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
623 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
625 hctx->ccid3hctx_no_feedback_timer.function =
626 ccid3_hc_tx_no_feedback_timer;
627 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
628 init_timer(&hctx->ccid3hctx_no_feedback_timer);
633 static void ccid3_hc_tx_exit(struct sock *sk)
635 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
637 BUG_ON(hctx == NULL);
639 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
640 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
642 /* Empty packet history */
643 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
646 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
648 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
650 /* Listen socks doesn't have a private CCID block */
651 if (sk->sk_state == DCCP_LISTEN)
654 BUG_ON(hctx == NULL);
656 info->tcpi_rto = hctx->ccid3hctx_t_rto;
657 info->tcpi_rtt = hctx->ccid3hctx_rtt;
660 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
661 u32 __user *optval, int __user *optlen)
663 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
666 /* Listen socks doesn't have a private CCID block */
667 if (sk->sk_state == DCCP_LISTEN)
671 case DCCP_SOCKOPT_CCID_TX_INFO:
672 if (len < sizeof(hctx->ccid3hctx_tfrc))
674 len = sizeof(hctx->ccid3hctx_tfrc);
675 val = &hctx->ccid3hctx_tfrc;
681 if (put_user(len, optlen) || copy_to_user(optval, val, len))
688 * Receiver Half-Connection Routines
690 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
691 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
693 static char *ccid3_rx_state_names[] = {
694 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
695 [TFRC_RSTATE_DATA] = "DATA",
696 [TFRC_RSTATE_TERM] = "TERM",
699 return ccid3_rx_state_names[state];
703 static void ccid3_hc_rx_set_state(struct sock *sk,
704 enum ccid3_hc_rx_states state)
706 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
707 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
709 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
710 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
711 ccid3_rx_state_name(state));
712 WARN_ON(state == oldstate);
713 hcrx->ccid3hcrx_state = state;
716 static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
718 if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */
719 ccid3_pr_debug("Packet payload length is 0 - not updating\n");
721 hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
722 (9 * hcrx->ccid3hcrx_s + len) / 10;
725 static void ccid3_hc_rx_send_feedback(struct sock *sk)
727 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
728 struct dccp_sock *dp = dccp_sk(sk);
729 struct dccp_rx_hist_entry *packet;
733 ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk);
735 dccp_timestamp(sk, &now);
737 switch (hcrx->ccid3hcrx_state) {
738 case TFRC_RSTATE_NO_DATA:
739 hcrx->ccid3hcrx_x_recv = 0;
741 case TFRC_RSTATE_DATA:
742 delta = timeval_delta(&now,
743 &hcrx->ccid3hcrx_tstamp_last_feedback);
744 DCCP_BUG_ON(delta < 0);
745 hcrx->ccid3hcrx_x_recv =
746 scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
748 case TFRC_RSTATE_TERM:
749 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
753 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
754 if (unlikely(packet == NULL)) {
755 DCCP_WARN("%s(%p), no data packet in history!\n",
760 hcrx->ccid3hcrx_tstamp_last_feedback = now;
761 hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval;
762 hcrx->ccid3hcrx_bytes_recv = 0;
764 /* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
765 delta = timeval_delta(&now, &packet->dccphrx_tstamp);
766 DCCP_BUG_ON(delta < 0);
767 hcrx->ccid3hcrx_elapsed_time = delta / 10;
769 if (hcrx->ccid3hcrx_p == 0)
770 hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
771 else if (hcrx->ccid3hcrx_p > 1000000) {
772 DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
773 hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
775 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
777 dp->dccps_hc_rx_insert_options = 1;
781 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
783 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
786 BUG_ON(hcrx == NULL);
788 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
791 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
793 if (dccp_packet_without_ack(skb))
796 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
797 pinv = htonl(hcrx->ccid3hcrx_pinv);
799 if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
800 dccp_insert_option_elapsed_time(sk, skb,
801 hcrx->ccid3hcrx_elapsed_time)) ||
802 dccp_insert_option_timestamp(sk, skb) ||
803 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
804 &pinv, sizeof(pinv)) ||
805 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
806 &x_recv, sizeof(x_recv)))
812 /* calculate first loss interval
814 * returns estimated loss interval in usecs */
816 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
818 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
819 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
821 suseconds_t rtt, delta;
822 struct timeval tstamp = { 0, };
828 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
830 if (dccp_rx_hist_entry_data_packet(entry)) {
835 tstamp = entry->dccphrx_tstamp;
836 win_count = entry->dccphrx_ccval;
840 interval = win_count - entry->dccphrx_ccval;
842 interval += TFRC_WIN_COUNT_LIMIT;
850 if (unlikely(step == 0)) {
851 DCCP_WARN("%s(%p), packet history has no data packets!\n",
856 if (unlikely(interval == 0)) {
857 DCCP_WARN("%s(%p), Could not find a win_count interval > 0."
858 "Defaulting to 1\n", dccp_role(sk), sk);
863 DCCP_CRIT("tail is null\n");
867 delta = timeval_delta(&tstamp, &tail->dccphrx_tstamp);
868 DCCP_BUG_ON(delta < 0);
870 rtt = delta * 4 / interval;
871 ccid3_pr_debug("%s(%p), approximated RTT to %dus\n",
872 dccp_role(sk), sk, (int)rtt);
875 * Determine the length of the first loss interval via inverse lookup.
876 * Assume that X_recv can be computed by the throughput equation
880 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
882 if (rtt == 0) { /* would result in divide-by-zero */
883 DCCP_WARN("RTT==0\n");
887 dccp_timestamp(sk, &tstamp);
888 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
889 DCCP_BUG_ON(delta <= 0);
891 x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
892 if (x_recv == 0) { /* would also trigger divide-by-zero */
893 DCCP_WARN("X_recv==0\n");
894 if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
895 DCCP_BUG("stored value of X_recv is zero");
900 fval = scaled_div(hcrx->ccid3hcrx_s, rtt);
901 fval = scaled_div32(fval, x_recv);
902 p = tfrc_calc_x_reverse_lookup(fval);
904 ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
905 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
913 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
915 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
916 struct dccp_li_hist_entry *head;
919 if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
920 if (!dccp_li_hist_interval_new(ccid3_li_hist,
921 &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss))
924 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
925 struct dccp_li_hist_entry, dccplih_node);
926 head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
928 struct dccp_li_hist_entry *entry;
929 struct list_head *tail;
931 head = list_entry(hcrx->ccid3hcrx_li_hist.next,
932 struct dccp_li_hist_entry, dccplih_node);
933 /* FIXME win count check removed as was wrong */
934 /* should make this check with receive history */
935 /* and compare there as per section 10.2 of RFC4342 */
937 /* new loss event detected */
938 /* calculate last interval length */
939 seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
940 entry = dccp_li_hist_entry_new(ccid3_li_hist, GFP_ATOMIC);
943 DCCP_BUG("out of memory - can not allocate entry");
947 list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist);
949 tail = hcrx->ccid3hcrx_li_hist.prev;
951 kmem_cache_free(ccid3_li_hist->dccplih_slab, tail);
953 /* Create the newest interval */
954 entry->dccplih_seqno = seq_loss;
955 entry->dccplih_interval = seq_temp;
956 entry->dccplih_win_count = win_loss;
960 static int ccid3_hc_rx_detect_loss(struct sock *sk,
961 struct dccp_rx_hist_entry *packet)
963 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
964 struct dccp_rx_hist_entry *rx_hist =
965 dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
966 u64 seqno = packet->dccphrx_seqno;
972 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
975 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
976 hcrx->ccid3hcrx_seqno_nonloss = seqno;
977 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
982 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
983 > TFRC_RECV_NUM_LATE_LOSS) {
985 ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss,
986 hcrx->ccid3hcrx_ccval_nonloss);
987 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
988 dccp_inc_seqno(&tmp_seqno);
989 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
990 dccp_inc_seqno(&tmp_seqno);
991 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
992 tmp_seqno, &ccval)) {
993 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
994 hcrx->ccid3hcrx_ccval_nonloss = ccval;
995 dccp_inc_seqno(&tmp_seqno);
999 /* FIXME - this code could be simplified with above while */
1000 /* but works at moment */
1001 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
1002 hcrx->ccid3hcrx_seqno_nonloss = seqno;
1003 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
1007 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
1008 &hcrx->ccid3hcrx_li_hist, packet,
1009 hcrx->ccid3hcrx_seqno_nonloss);
1013 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
1015 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1016 const struct dccp_options_received *opt_recv;
1017 struct dccp_rx_hist_entry *packet;
1019 u32 p_prev, rtt_prev;
1020 suseconds_t r_sample, t_elapsed;
1021 int loss, payload_size;
1023 BUG_ON(hcrx == NULL);
1025 opt_recv = &dccp_sk(sk)->dccps_options_received;
1027 switch (DCCP_SKB_CB(skb)->dccpd_type) {
1029 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1031 case DCCP_PKT_DATAACK:
1032 if (opt_recv->dccpor_timestamp_echo == 0)
1034 rtt_prev = hcrx->ccid3hcrx_rtt;
1035 dccp_timestamp(sk, &now);
1036 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
1037 r_sample = timeval_usecs(&now);
1038 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
1040 DCCP_BUG_ON(r_sample < 0);
1041 if (unlikely(r_sample <= t_elapsed))
1042 DCCP_WARN("r_sample=%ldus, t_elapsed=%ldus\n",
1043 (long)r_sample, (long)t_elapsed);
1045 r_sample -= t_elapsed;
1046 CCID3_RTT_SANITY_CHECK(r_sample);
1048 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
1049 hcrx->ccid3hcrx_rtt = r_sample;
1051 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
1054 if (rtt_prev != hcrx->ccid3hcrx_rtt)
1055 ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n",
1056 dccp_role(sk), sk, hcrx->ccid3hcrx_rtt,
1057 opt_recv->dccpor_elapsed_time);
1061 default: /* We're not interested in other packet types, move along */
1065 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
1067 if (unlikely(packet == NULL)) {
1068 DCCP_WARN("%s(%p), Not enough mem to add rx packet "
1069 "to history, consider it lost!\n", dccp_role(sk), sk);
1073 loss = ccid3_hc_rx_detect_loss(sk, packet);
1075 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
1078 payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
1079 ccid3_hc_rx_update_s(hcrx, payload_size);
1081 switch (hcrx->ccid3hcrx_state) {
1082 case TFRC_RSTATE_NO_DATA:
1083 ccid3_pr_debug("%s(%p, state=%s), skb=%p, sending initial "
1084 "feedback\n", dccp_role(sk), sk,
1085 dccp_state_name(sk->sk_state), skb);
1086 ccid3_hc_rx_send_feedback(sk);
1087 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
1089 case TFRC_RSTATE_DATA:
1090 hcrx->ccid3hcrx_bytes_recv += payload_size;
1094 dccp_timestamp(sk, &now);
1095 if ((timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
1096 (suseconds_t)hcrx->ccid3hcrx_rtt) >= 0) {
1097 hcrx->ccid3hcrx_tstamp_last_ack = now;
1098 ccid3_hc_rx_send_feedback(sk);
1101 case TFRC_RSTATE_TERM:
1102 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
1106 /* Dealing with packet loss */
1107 ccid3_pr_debug("%s(%p, state=%s), data loss! Reacting...\n",
1108 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1110 p_prev = hcrx->ccid3hcrx_p;
1112 /* Calculate loss event rate */
1113 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1114 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1116 /* Scaling up by 1000000 as fixed decimal */
1118 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1120 DCCP_BUG("empty loss history");
1122 if (hcrx->ccid3hcrx_p > p_prev) {
1123 ccid3_hc_rx_send_feedback(sk);
1128 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1130 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1132 ccid3_pr_debug("entry\n");
1134 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1135 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1136 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1137 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1138 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1139 hcrx->ccid3hcrx_s = 0;
1140 hcrx->ccid3hcrx_rtt = 0;
1144 static void ccid3_hc_rx_exit(struct sock *sk)
1146 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1148 BUG_ON(hcrx == NULL);
1150 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1152 /* Empty packet history */
1153 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1155 /* Empty loss interval history */
1156 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1159 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1161 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1163 /* Listen socks doesn't have a private CCID block */
1164 if (sk->sk_state == DCCP_LISTEN)
1167 BUG_ON(hcrx == NULL);
1169 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1170 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1171 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1174 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1175 u32 __user *optval, int __user *optlen)
1177 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1180 /* Listen socks doesn't have a private CCID block */
1181 if (sk->sk_state == DCCP_LISTEN)
1185 case DCCP_SOCKOPT_CCID_RX_INFO:
1186 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1188 len = sizeof(hcrx->ccid3hcrx_tfrc);
1189 val = &hcrx->ccid3hcrx_tfrc;
1192 return -ENOPROTOOPT;
1195 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1201 static struct ccid_operations ccid3 = {
1202 .ccid_id = DCCPC_CCID3,
1203 .ccid_name = "ccid3",
1204 .ccid_owner = THIS_MODULE,
1205 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1206 .ccid_hc_tx_init = ccid3_hc_tx_init,
1207 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1208 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1209 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1210 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1211 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1212 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1213 .ccid_hc_rx_init = ccid3_hc_rx_init,
1214 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1215 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1216 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1217 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1218 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1219 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1220 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1223 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1224 module_param(ccid3_debug, int, 0444);
1225 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1228 static __init int ccid3_module_init(void)
1232 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1233 if (ccid3_rx_hist == NULL)
1236 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1237 if (ccid3_tx_hist == NULL)
1240 ccid3_li_hist = dccp_li_hist_new("ccid3");
1241 if (ccid3_li_hist == NULL)
1244 rc = ccid_register(&ccid3);
1246 goto out_free_loss_interval_history;
1250 out_free_loss_interval_history:
1251 dccp_li_hist_delete(ccid3_li_hist);
1252 ccid3_li_hist = NULL;
1254 dccp_tx_hist_delete(ccid3_tx_hist);
1255 ccid3_tx_hist = NULL;
1257 dccp_rx_hist_delete(ccid3_rx_hist);
1258 ccid3_rx_hist = NULL;
1261 module_init(ccid3_module_init);
1263 static __exit void ccid3_module_exit(void)
1265 ccid_unregister(&ccid3);
1267 if (ccid3_tx_hist != NULL) {
1268 dccp_tx_hist_delete(ccid3_tx_hist);
1269 ccid3_tx_hist = NULL;
1271 if (ccid3_rx_hist != NULL) {
1272 dccp_rx_hist_delete(ccid3_rx_hist);
1273 ccid3_rx_hist = NULL;
1275 if (ccid3_li_hist != NULL) {
1276 dccp_li_hist_delete(ccid3_li_hist);
1277 ccid3_li_hist = NULL;
1280 module_exit(ccid3_module_exit);
1282 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1283 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1284 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1285 MODULE_LICENSE("GPL");
1286 MODULE_ALIAS("net-dccp-ccid-3");