2 * net/dccp/ccids/ccid3.c
4 * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
5 * Copyright (c) 2005-7 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;
54 * Transmitter Half-Connection Routines
56 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
57 static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
59 static char *ccid3_state_names[] = {
60 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
61 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
62 [TFRC_SSTATE_FBACK] = "FBACK",
63 [TFRC_SSTATE_TERM] = "TERM",
66 return ccid3_state_names[state];
70 static void ccid3_hc_tx_set_state(struct sock *sk,
71 enum ccid3_hc_tx_states state)
73 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
74 enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
76 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
77 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
78 ccid3_tx_state_name(state));
79 WARN_ON(state == oldstate);
80 hctx->ccid3hctx_state = state;
84 * Compute the initial sending rate X_init according to RFC 3390:
85 * w_init = min(4 * MSS, max(2 * MSS, 4380 bytes))
86 * X_init = w_init / RTT
87 * For consistency with other parts of the code, X_init is scaled by 2^6.
89 static inline u64 rfc3390_initial_rate(struct sock *sk)
91 const struct dccp_sock *dp = dccp_sk(sk);
92 const __u32 w_init = min(4 * dp->dccps_mss_cache,
93 max(2 * dp->dccps_mss_cache, 4380U));
95 return scaled_div(w_init << 6, ccid3_hc_tx_sk(sk)->ccid3hctx_rtt);
99 * Recalculate t_ipi and delta (should be called whenever X changes)
101 static inline void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx)
103 /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
104 hctx->ccid3hctx_t_ipi = scaled_div32(((u64)hctx->ccid3hctx_s) << 6,
107 /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
108 hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
109 TFRC_OPSYS_HALF_TIME_GRAN);
111 ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n",
112 hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta,
113 hctx->ccid3hctx_s, (unsigned)(hctx->ccid3hctx_x >> 6));
119 * X_calc = calcX(s, R, p);
120 * X = max(min(X_calc, 2 * X_recv), s / t_mbi);
122 * If (now - tld >= R)
123 * X = max(min(2 * X, 2 * X_recv), s / R);
126 * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
127 * fine-grained resolution of sending rates. This requires scaling by 2^6
128 * throughout the code. Only X_calc is unscaled (in bytes/second).
131 static void ccid3_hc_tx_update_x(struct sock *sk)
134 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
135 __u64 min_rate = 2 * hctx->ccid3hctx_x_recv;
136 const __u64 old_x = hctx->ccid3hctx_x;
139 * Handle IDLE periods: do not reduce below RFC3390 initial sending rate
140 * when idling [RFC 4342, 5.1]. See also draft-ietf-dccp-rfc3448bis.
141 * For consistency with X and X_recv, min_rate is also scaled by 2^6.
143 if (unlikely(hctx->ccid3hctx_idle)) {
144 min_rate = rfc3390_initial_rate(sk);
145 min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv);
148 if (hctx->ccid3hctx_p > 0) {
150 hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
152 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
153 (((__u64)hctx->ccid3hctx_s) << 6) /
157 const ktime_t now = ktime_get_real();
159 if ((ktime_us_delta(now, hctx->ccid3hctx_t_ld) -
160 (s64)hctx->ccid3hctx_rtt) >= 0) {
163 max(min(2 * hctx->ccid3hctx_x, min_rate),
164 scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
165 hctx->ccid3hctx_rtt));
166 hctx->ccid3hctx_t_ld = now;
170 if (hctx->ccid3hctx_x != old_x) {
171 ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
172 "X_recv=%u\n", (unsigned)(old_x >> 6),
173 (unsigned)(hctx->ccid3hctx_x >> 6),
174 hctx->ccid3hctx_x_calc,
175 (unsigned)(hctx->ccid3hctx_x_recv >> 6));
177 ccid3_update_send_interval(hctx);
182 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
183 * @len: DCCP packet payload size in bytes
185 static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
187 const u16 old_s = hctx->ccid3hctx_s;
189 hctx->ccid3hctx_s = old_s == 0 ? len : (9 * old_s + len) / 10;
191 if (hctx->ccid3hctx_s != old_s)
192 ccid3_update_send_interval(hctx);
196 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
197 * The algorithm is not applicable if RTT < 4 microseconds.
199 static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
204 if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */
207 quarter_rtts = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count);
208 quarter_rtts /= hctx->ccid3hctx_rtt / 4;
210 if (quarter_rtts > 0) {
211 hctx->ccid3hctx_t_last_win_count = now;
212 hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5);
213 hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
217 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
219 struct sock *sk = (struct sock *)data;
220 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
221 unsigned long t_nfb = USEC_PER_SEC / 5;
224 if (sock_owned_by_user(sk)) {
225 /* Try again later. */
226 /* XXX: set some sensible MIB */
230 ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
231 ccid3_tx_state_name(hctx->ccid3hctx_state));
233 hctx->ccid3hctx_idle = 1;
235 switch (hctx->ccid3hctx_state) {
236 case TFRC_SSTATE_NO_FBACK:
237 /* RFC 3448, 4.4: Halve send rate directly */
238 hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
239 (((__u64)hctx->ccid3hctx_s) << 6) /
242 ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u "
243 "bytes/s\n", dccp_role(sk), sk,
244 ccid3_tx_state_name(hctx->ccid3hctx_state),
245 (unsigned)(hctx->ccid3hctx_x >> 6));
246 /* The value of R is still undefined and so we can not recompute
247 * the timout value. Keep initial value as per [RFC 4342, 5]. */
248 t_nfb = TFRC_INITIAL_TIMEOUT;
249 ccid3_update_send_interval(hctx);
251 case TFRC_SSTATE_FBACK:
253 * Modify the cached value of X_recv [RFC 3448, 4.4]
255 * If (p == 0 || X_calc > 2 * X_recv)
256 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
258 * X_recv = X_calc / 4;
260 * Note that X_recv is scaled by 2^6 while X_calc is not
262 BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
264 if (hctx->ccid3hctx_p == 0 ||
265 (hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5))) {
267 hctx->ccid3hctx_x_recv =
268 max(hctx->ccid3hctx_x_recv / 2,
269 (((__u64)hctx->ccid3hctx_s) << 6) /
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);
278 * Schedule no feedback timer to expire in
279 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
280 * See comments in packet_recv() regarding the value of t_RTO.
282 t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
284 case TFRC_SSTATE_NO_SENT:
285 DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk);
287 case TFRC_SSTATE_TERM:
292 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
293 jiffies + usecs_to_jiffies(t_nfb));
301 * > 0: delay (in msecs) that should pass before actually sending
302 * = 0: can send immediately
303 * < 0: error condition; do not send packet
305 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
307 struct dccp_sock *dp = dccp_sk(sk);
308 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
309 ktime_t now = ktime_get_real();
312 BUG_ON(hctx == NULL);
315 * This function is called only for Data and DataAck packets. Sending
316 * zero-sized Data(Ack)s is theoretically possible, but for congestion
317 * control this case is pathological - ignore it.
319 if (unlikely(skb->len == 0))
322 switch (hctx->ccid3hctx_state) {
323 case TFRC_SSTATE_NO_SENT:
324 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
326 usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
327 hctx->ccid3hctx_last_win_count = 0;
328 hctx->ccid3hctx_t_last_win_count = now;
330 /* Set t_0 for initial packet */
331 hctx->ccid3hctx_t_nom = now;
333 hctx->ccid3hctx_s = skb->len;
336 * Use initial RTT sample when available: recommended by erratum
337 * to RFC 4342. This implements the initialisation procedure of
338 * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6.
340 if (dp->dccps_syn_rtt) {
341 ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
342 hctx->ccid3hctx_rtt = dp->dccps_syn_rtt;
343 hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
344 hctx->ccid3hctx_t_ld = now;
346 /* Sender does not have RTT sample: X = MSS/second */
347 hctx->ccid3hctx_x = dp->dccps_mss_cache;
348 hctx->ccid3hctx_x <<= 6;
350 ccid3_update_send_interval(hctx);
352 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
354 case TFRC_SSTATE_NO_FBACK:
355 case TFRC_SSTATE_FBACK:
356 delay = ktime_us_delta(hctx->ccid3hctx_t_nom, now);
357 ccid3_pr_debug("delay=%ld\n", (long)delay);
359 * Scheduling of packet transmissions [RFC 3448, 4.6]
361 * if (t_now > t_nom - delta)
362 * // send the packet now
364 * // send the packet in (t_nom - t_now) milliseconds.
366 if (delay - (s64)hctx->ccid3hctx_delta >= 1000)
367 return (u32)delay / 1000L;
369 ccid3_hc_tx_update_win_count(hctx, now);
371 case TFRC_SSTATE_TERM:
372 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
376 /* prepare to send now (add options etc.) */
377 dp->dccps_hc_tx_insert_options = 1;
378 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
379 hctx->ccid3hctx_idle = 0;
381 /* set the nominal send time for the next following packet */
382 hctx->ccid3hctx_t_nom = ktime_add_us(hctx->ccid3hctx_t_nom,
383 hctx->ccid3hctx_t_ipi);
387 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
390 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
391 struct dccp_tx_hist_entry *packet;
393 BUG_ON(hctx == NULL);
395 ccid3_hc_tx_update_s(hctx, len);
397 packet = dccp_tx_hist_entry_new(ccid3_tx_hist, GFP_ATOMIC);
398 if (unlikely(packet == NULL)) {
399 DCCP_CRIT("packet history - out of memory!");
402 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
404 packet->dccphtx_tstamp = ktime_to_timeval(ktime_get_real());
405 packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
406 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
407 packet->dccphtx_sent = 1;
410 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
412 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
413 struct ccid3_options_received *opt_recv;
414 struct dccp_tx_hist_entry *packet;
419 BUG_ON(hctx == NULL);
421 /* we are only interested in ACKs */
422 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
423 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
426 opt_recv = &hctx->ccid3hctx_options_received;
428 switch (hctx->ccid3hctx_state) {
429 case TFRC_SSTATE_NO_FBACK:
430 case TFRC_SSTATE_FBACK:
431 /* get packet from history to look up t_recvdata */
432 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
433 DCCP_SKB_CB(skb)->dccpd_ack_seq);
434 if (unlikely(packet == NULL)) {
435 DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
436 "in history!\n", dccp_role(sk), sk,
437 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
438 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
442 /* Update receive rate in units of 64 * bytes/second */
443 hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
444 hctx->ccid3hctx_x_recv <<= 6;
446 /* Update loss event rate */
447 pinv = opt_recv->ccid3or_loss_event_rate;
448 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
449 hctx->ccid3hctx_p = 0;
450 else /* can not exceed 100% */
451 hctx->ccid3hctx_p = 1000000 / pinv;
453 now = ktime_get_real();
454 t_hist = timeval_to_ktime(packet->dccphtx_tstamp);
456 * Calculate new round trip sample as per [RFC 3448, 4.3] by
457 * R_sample = (now - t_recvdata) - t_elapsed
459 r_sample = dccp_sample_rtt(sk, now, &t_hist);
462 * Update RTT estimate by
463 * If (No feedback recv)
466 * R = q * R + (1 - q) * R_sample;
468 * q is a constant, RFC 3448 recomments 0.9
470 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
472 * Larger Initial Windows [RFC 4342, sec. 5]
474 hctx->ccid3hctx_rtt = r_sample;
475 hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
476 hctx->ccid3hctx_t_ld = now;
478 ccid3_update_send_interval(hctx);
480 ccid3_pr_debug("%s(%p), s=%u, MSS=%u, "
481 "R_sample=%uus, X=%u\n", dccp_role(sk),
482 sk, hctx->ccid3hctx_s,
483 dccp_sk(sk)->dccps_mss_cache, r_sample,
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);
499 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
500 "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
502 sk, hctx->ccid3hctx_rtt, 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 now = ktime_get_real();
737 switch (hcrx->ccid3hcrx_state) {
738 case TFRC_RSTATE_NO_DATA:
739 hcrx->ccid3hcrx_x_recv = 0;
741 case TFRC_RSTATE_DATA:
742 delta = ktime_us_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 = ktime_us_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 static int ccid3_hc_rx_detect_loss(struct sock *sk,
813 struct dccp_rx_hist_entry *packet)
815 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
816 struct dccp_rx_hist_entry *rx_hist =
817 dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
818 u64 seqno = packet->dccphrx_seqno;
824 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
827 follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
828 hcrx->ccid3hcrx_seqno_nonloss = seqno;
829 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
834 while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
835 > TFRC_RECV_NUM_LATE_LOSS) {
837 dccp_li_update_li(sk,
838 &hcrx->ccid3hcrx_li_hist,
839 &hcrx->ccid3hcrx_hist,
840 hcrx->ccid3hcrx_tstamp_last_feedback,
842 hcrx->ccid3hcrx_bytes_recv,
843 hcrx->ccid3hcrx_x_recv,
844 hcrx->ccid3hcrx_seqno_nonloss,
845 hcrx->ccid3hcrx_ccval_nonloss);
846 tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
847 dccp_inc_seqno(&tmp_seqno);
848 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
849 dccp_inc_seqno(&tmp_seqno);
850 while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
851 tmp_seqno, &ccval)) {
852 hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
853 hcrx->ccid3hcrx_ccval_nonloss = ccval;
854 dccp_inc_seqno(&tmp_seqno);
858 /* FIXME - this code could be simplified with above while */
859 /* but works at moment */
860 if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
861 hcrx->ccid3hcrx_seqno_nonloss = seqno;
862 hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
866 dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
867 &hcrx->ccid3hcrx_li_hist, packet,
868 hcrx->ccid3hcrx_seqno_nonloss);
872 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
874 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
875 const struct dccp_options_received *opt_recv;
876 struct dccp_rx_hist_entry *packet;
877 u32 p_prev, r_sample, rtt_prev;
878 int loss, payload_size;
881 BUG_ON(hcrx == NULL);
883 opt_recv = &dccp_sk(sk)->dccps_options_received;
885 switch (DCCP_SKB_CB(skb)->dccpd_type) {
887 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
889 case DCCP_PKT_DATAACK:
890 if (opt_recv->dccpor_timestamp_echo == 0)
892 rtt_prev = hcrx->ccid3hcrx_rtt;
893 now = ktime_get_real();
894 r_sample = dccp_sample_rtt(sk, now, NULL);
896 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
897 hcrx->ccid3hcrx_rtt = r_sample;
899 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
902 if (rtt_prev != hcrx->ccid3hcrx_rtt)
903 ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n",
904 dccp_role(sk), sk, hcrx->ccid3hcrx_rtt,
905 opt_recv->dccpor_elapsed_time);
909 default: /* We're not interested in other packet types, move along */
913 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, opt_recv->dccpor_ndp,
915 if (unlikely(packet == NULL)) {
916 DCCP_WARN("%s(%p), Not enough mem to add rx packet "
917 "to history, consider it lost!\n", dccp_role(sk), sk);
921 loss = ccid3_hc_rx_detect_loss(sk, packet);
923 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
926 payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
927 ccid3_hc_rx_update_s(hcrx, payload_size);
929 switch (hcrx->ccid3hcrx_state) {
930 case TFRC_RSTATE_NO_DATA:
931 ccid3_pr_debug("%s(%p, state=%s), skb=%p, sending initial "
932 "feedback\n", dccp_role(sk), sk,
933 dccp_state_name(sk->sk_state), skb);
934 ccid3_hc_rx_send_feedback(sk);
935 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
937 case TFRC_RSTATE_DATA:
938 hcrx->ccid3hcrx_bytes_recv += payload_size;
942 now = ktime_get_real();
943 if ((ktime_us_delta(now, hcrx->ccid3hcrx_tstamp_last_ack) -
944 (s64)hcrx->ccid3hcrx_rtt) >= 0) {
945 hcrx->ccid3hcrx_tstamp_last_ack = now;
946 ccid3_hc_rx_send_feedback(sk);
949 case TFRC_RSTATE_TERM:
950 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
954 /* Dealing with packet loss */
955 ccid3_pr_debug("%s(%p, state=%s), data loss! Reacting...\n",
956 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
958 p_prev = hcrx->ccid3hcrx_p;
960 /* Calculate loss event rate */
961 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
962 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
964 /* Scaling up by 1000000 as fixed decimal */
966 hcrx->ccid3hcrx_p = 1000000 / i_mean;
968 DCCP_BUG("empty loss history");
970 if (hcrx->ccid3hcrx_p > p_prev) {
971 ccid3_hc_rx_send_feedback(sk);
976 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
978 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
980 ccid3_pr_debug("entry\n");
982 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
983 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
984 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
985 hcrx->ccid3hcrx_tstamp_last_feedback =
986 hcrx->ccid3hcrx_tstamp_last_ack = ktime_get_real();
987 hcrx->ccid3hcrx_s = 0;
988 hcrx->ccid3hcrx_rtt = 0;
992 static void ccid3_hc_rx_exit(struct sock *sk)
994 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
996 BUG_ON(hcrx == NULL);
998 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1000 /* Empty packet history */
1001 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1003 /* Empty loss interval history */
1004 dccp_li_hist_purge(&hcrx->ccid3hcrx_li_hist);
1007 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1009 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1011 /* Listen socks doesn't have a private CCID block */
1012 if (sk->sk_state == DCCP_LISTEN)
1015 BUG_ON(hcrx == NULL);
1017 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1018 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1019 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1022 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1023 u32 __user *optval, int __user *optlen)
1025 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1028 /* Listen socks doesn't have a private CCID block */
1029 if (sk->sk_state == DCCP_LISTEN)
1033 case DCCP_SOCKOPT_CCID_RX_INFO:
1034 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1036 len = sizeof(hcrx->ccid3hcrx_tfrc);
1037 val = &hcrx->ccid3hcrx_tfrc;
1040 return -ENOPROTOOPT;
1043 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1049 static struct ccid_operations ccid3 = {
1050 .ccid_id = DCCPC_CCID3,
1051 .ccid_name = "ccid3",
1052 .ccid_owner = THIS_MODULE,
1053 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1054 .ccid_hc_tx_init = ccid3_hc_tx_init,
1055 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1056 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1057 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1058 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1059 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1060 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1061 .ccid_hc_rx_init = ccid3_hc_rx_init,
1062 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1063 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1064 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1065 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1066 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1067 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1068 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1071 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1072 module_param(ccid3_debug, int, 0444);
1073 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1076 static __init int ccid3_module_init(void)
1080 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1081 if (ccid3_rx_hist == NULL)
1084 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1085 if (ccid3_tx_hist == NULL)
1088 rc = ccid_register(&ccid3);
1095 dccp_tx_hist_delete(ccid3_tx_hist);
1096 ccid3_tx_hist = NULL;
1098 dccp_rx_hist_delete(ccid3_rx_hist);
1099 ccid3_rx_hist = NULL;
1102 module_init(ccid3_module_init);
1104 static __exit void ccid3_module_exit(void)
1106 ccid_unregister(&ccid3);
1108 if (ccid3_tx_hist != NULL) {
1109 dccp_tx_hist_delete(ccid3_tx_hist);
1110 ccid3_tx_hist = NULL;
1112 if (ccid3_rx_hist != NULL) {
1113 dccp_rx_hist_delete(ccid3_rx_hist);
1114 ccid3_rx_hist = NULL;
1117 module_exit(ccid3_module_exit);
1119 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1120 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1121 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1122 MODULE_LICENSE("GPL");
1123 MODULE_ALIAS("net-dccp-ccid-3");