2 * net/dccp/ccids/ccid3.c
4 * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
5 * Copyright (c) 2005-6 Ian McDonald <imcdnzl@gmail.com>
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.
37 #include <linux/config.h>
40 #include "lib/packet_history.h"
41 #include "lib/loss_interval.h"
46 * Reason for maths here is to avoid 32 bit overflow when a is big.
47 * With this we get close to the limit.
49 static inline u32 usecs_div(const u32 a, const u32 b)
51 const u32 div = a < (UINT_MAX / (USEC_PER_SEC / 10)) ? 10 :
52 a < (UINT_MAX / (USEC_PER_SEC / 50)) ? 50 :
53 a < (UINT_MAX / (USEC_PER_SEC / 100)) ? 100 :
54 a < (UINT_MAX / (USEC_PER_SEC / 500)) ? 500 :
55 a < (UINT_MAX / (USEC_PER_SEC / 1000)) ? 1000 :
56 a < (UINT_MAX / (USEC_PER_SEC / 5000)) ? 5000 :
57 a < (UINT_MAX / (USEC_PER_SEC / 10000)) ? 10000 :
58 a < (UINT_MAX / (USEC_PER_SEC / 50000)) ? 50000 :
60 const u32 tmp = a * (USEC_PER_SEC / div);
61 return (b >= 2 * div) ? tmp / (b / div) : tmp;
64 static int ccid3_debug;
67 #define ccid3_pr_debug(format, a...) \
68 do { if (ccid3_debug) \
69 printk(KERN_DEBUG "%s: " format, __FUNCTION__, ##a); \
72 #define ccid3_pr_debug(format, a...)
75 static struct dccp_tx_hist *ccid3_tx_hist;
76 static struct dccp_rx_hist *ccid3_rx_hist;
77 static struct dccp_li_hist *ccid3_li_hist;
79 /* TFRC sender states */
80 enum ccid3_hc_tx_states {
81 TFRC_SSTATE_NO_SENT = 1,
88 static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
90 static char *ccid3_state_names[] = {
91 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
92 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
93 [TFRC_SSTATE_FBACK] = "FBACK",
94 [TFRC_SSTATE_TERM] = "TERM",
97 return ccid3_state_names[state];
101 static inline void ccid3_hc_tx_set_state(struct sock *sk,
102 enum ccid3_hc_tx_states state)
104 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
105 enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
107 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
108 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
109 ccid3_tx_state_name(state));
110 WARN_ON(state == oldstate);
111 hctx->ccid3hctx_state = state;
114 /* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */
115 static inline void ccid3_calc_new_t_ipi(struct ccid3_hc_tx_sock *hctx)
118 * If no feedback spec says t_ipi is 1 second (set elsewhere and then
119 * doubles after every no feedback timer (separate function)
121 if (hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
122 hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s,
126 /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
127 static inline void ccid3_calc_new_delta(struct ccid3_hc_tx_sock *hctx)
129 hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
130 TFRC_OPSYS_HALF_TIME_GRAN);
136 * x_calc = calcX(s, R, p);
137 * X = max(min(X_calc, 2 * X_recv), s / t_mbi);
139 * If (now - tld >= R)
140 * X = max(min(2 * X, 2 * X_recv), s / R);
143 static void ccid3_hc_tx_update_x(struct sock *sk)
145 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
147 /* To avoid large error in calcX */
148 if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) {
149 hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s,
152 hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_calc,
153 2 * hctx->ccid3hctx_x_recv),
155 TFRC_MAX_BACK_OFF_TIME));
159 dccp_timestamp(sk, &now);
160 if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >=
161 hctx->ccid3hctx_rtt) {
162 hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_recv,
163 hctx->ccid3hctx_x) * 2,
164 usecs_div(hctx->ccid3hctx_s,
165 hctx->ccid3hctx_rtt));
166 hctx->ccid3hctx_t_ld = now;
171 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
173 struct sock *sk = (struct sock *)data;
174 unsigned long next_tmout = 0;
175 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
178 if (sock_owned_by_user(sk)) {
179 /* Try again later. */
180 /* XXX: set some sensible MIB */
181 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
186 ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
187 ccid3_tx_state_name(hctx->ccid3hctx_state));
189 switch (hctx->ccid3hctx_state) {
190 case TFRC_SSTATE_TERM:
192 case TFRC_SSTATE_NO_FBACK:
193 /* Halve send rate */
194 hctx->ccid3hctx_x /= 2;
195 if (hctx->ccid3hctx_x < (hctx->ccid3hctx_s /
196 TFRC_MAX_BACK_OFF_TIME))
197 hctx->ccid3hctx_x = (hctx->ccid3hctx_s /
198 TFRC_MAX_BACK_OFF_TIME);
200 ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %d "
203 ccid3_tx_state_name(hctx->ccid3hctx_state),
205 next_tmout = max_t(u32, 2 * usecs_div(hctx->ccid3hctx_s,
207 TFRC_INITIAL_TIMEOUT);
209 * FIXME - not sure above calculation is correct. See section
210 * 5 of CCID3 11 should adjust tx_t_ipi and double that to
214 case TFRC_SSTATE_FBACK:
216 * Check if IDLE since last timeout and recv rate is less than
219 if (!hctx->ccid3hctx_idle ||
220 (hctx->ccid3hctx_x_recv >=
221 4 * usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt))) {
222 ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
224 ccid3_tx_state_name(hctx->ccid3hctx_state));
225 /* Halve sending rate */
227 /* If (X_calc > 2 * X_recv)
228 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
230 * X_recv = X_calc / 4;
232 BUG_ON(hctx->ccid3hctx_p >= TFRC_SMALLEST_P &&
233 hctx->ccid3hctx_x_calc == 0);
235 /* check also if p is zero -> x_calc is infinity? */
236 if (hctx->ccid3hctx_p < TFRC_SMALLEST_P ||
237 hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv)
238 hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2,
239 hctx->ccid3hctx_s / (2 * TFRC_MAX_BACK_OFF_TIME));
241 hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc / 4;
243 /* Update sending rate */
244 ccid3_hc_tx_update_x(sk);
247 * Schedule no feedback timer to expire in
248 * max(4 * R, 2 * s / X)
250 next_tmout = max_t(u32, hctx->ccid3hctx_t_rto,
251 2 * usecs_div(hctx->ccid3hctx_s,
255 printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
256 __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
261 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
262 jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
263 hctx->ccid3hctx_idle = 1;
269 static int ccid3_hc_tx_send_packet(struct sock *sk,
270 struct sk_buff *skb, int len)
272 struct dccp_sock *dp = dccp_sk(sk);
273 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
274 struct dccp_tx_hist_entry *new_packet;
279 BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
281 /* Check if pure ACK or Terminating*/
283 * XXX: We only call this function for DATA and DATAACK, on, these
284 * packets can have zero length, but why the comment about "pure ACK"?
286 if (unlikely(len == 0))
289 /* See if last packet allocated was not sent */
290 new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
291 if (new_packet == NULL || new_packet->dccphtx_sent) {
292 new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
296 if (unlikely(new_packet == NULL)) {
297 LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, not enough "
298 "mem to add to history, send refused\n",
299 __FUNCTION__, dccp_role(sk), sk);
303 dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
306 dccp_timestamp(sk, &now);
308 switch (hctx->ccid3hctx_state) {
309 case TFRC_SSTATE_NO_SENT:
310 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
311 jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
312 hctx->ccid3hctx_last_win_count = 0;
313 hctx->ccid3hctx_t_last_win_count = now;
314 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
315 hctx->ccid3hctx_t_ipi = TFRC_INITIAL_IPI;
317 /* Set nominal send time for initial packet */
318 hctx->ccid3hctx_t_nom = now;
319 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
320 hctx->ccid3hctx_t_ipi);
321 ccid3_calc_new_delta(hctx);
324 case TFRC_SSTATE_NO_FBACK:
325 case TFRC_SSTATE_FBACK:
326 delay = (timeval_delta(&now, &hctx->ccid3hctx_t_nom) -
327 hctx->ccid3hctx_delta);
329 /* divide by -1000 is to convert to ms and get sign right */
330 rc = delay > 0 ? delay : 0;
333 printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
334 __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
340 /* Can we send? if so add options and add to packet history */
342 dp->dccps_hc_tx_insert_options = 1;
343 new_packet->dccphtx_ccval =
344 DCCP_SKB_CB(skb)->dccpd_ccval =
345 hctx->ccid3hctx_last_win_count;
351 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
353 const struct dccp_sock *dp = dccp_sk(sk);
354 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
357 BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
359 dccp_timestamp(sk, &now);
361 /* check if we have sent a data packet */
363 unsigned long quarter_rtt;
364 struct dccp_tx_hist_entry *packet;
366 packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
367 if (unlikely(packet == NULL)) {
368 LIMIT_NETDEBUG(KERN_WARNING "%s: packet doesn't "
369 "exists in history!\n", __FUNCTION__);
372 if (unlikely(packet->dccphtx_sent)) {
373 LIMIT_NETDEBUG(KERN_WARNING "%s: no unsent packet in "
374 "history!\n", __FUNCTION__);
377 packet->dccphtx_tstamp = now;
378 packet->dccphtx_seqno = dp->dccps_gss;
380 * Check if win_count have changed
381 * Algorithm in "8.1. Window Counter Valuer" in
382 * draft-ietf-dccp-ccid3-11.txt
384 quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
385 if (likely(hctx->ccid3hctx_rtt > 8))
386 quarter_rtt /= hctx->ccid3hctx_rtt / 4;
388 if (quarter_rtt > 0) {
389 hctx->ccid3hctx_t_last_win_count = now;
390 hctx->ccid3hctx_last_win_count = (hctx->ccid3hctx_last_win_count +
391 min_t(unsigned long, quarter_rtt, 5)) % 16;
392 ccid3_pr_debug("%s, sk=%p, window changed from "
395 packet->dccphtx_ccval,
396 hctx->ccid3hctx_last_win_count);
399 hctx->ccid3hctx_idle = 0;
400 packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
401 packet->dccphtx_sent = 1;
403 ccid3_pr_debug("%s, sk=%p, seqno=%llu NOT inserted!\n",
404 dccp_role(sk), sk, dp->dccps_gss);
406 switch (hctx->ccid3hctx_state) {
407 case TFRC_SSTATE_NO_SENT:
408 /* if first wasn't pure ack */
410 printk(KERN_CRIT "%s: %s, First packet sent is noted "
411 "as a data packet\n",
412 __FUNCTION__, dccp_role(sk));
414 case TFRC_SSTATE_NO_FBACK:
415 case TFRC_SSTATE_FBACK:
417 hctx->ccid3hctx_t_nom = now;
418 ccid3_calc_new_t_ipi(hctx);
419 ccid3_calc_new_delta(hctx);
420 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
421 hctx->ccid3hctx_t_ipi);
425 printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
426 __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
432 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
434 const struct dccp_sock *dp = dccp_sk(sk);
435 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
436 struct ccid3_options_received *opt_recv;
437 struct dccp_tx_hist_entry *packet;
439 unsigned long next_tmout;
445 BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
447 /* we are only interested in ACKs */
448 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
449 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
452 opt_recv = &hctx->ccid3hctx_options_received;
454 t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
455 x_recv = opt_recv->ccid3or_receive_rate;
456 pinv = opt_recv->ccid3or_loss_event_rate;
458 switch (hctx->ccid3hctx_state) {
459 case TFRC_SSTATE_NO_SENT:
460 /* FIXME: what to do here? */
462 case TFRC_SSTATE_NO_FBACK:
463 case TFRC_SSTATE_FBACK:
464 /* Calculate new round trip sample by
465 * R_sample = (now - t_recvdata) - t_delay */
466 /* get t_recvdata from history */
467 packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
468 DCCP_SKB_CB(skb)->dccpd_ack_seq);
469 if (unlikely(packet == NULL)) {
470 LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, seqno "
471 "%llu(%s) does't exist in history!\n",
472 __FUNCTION__, dccp_role(sk), sk,
473 (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
474 dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
479 dccp_timestamp(sk, &now);
480 r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
481 if (unlikely(r_sample <= t_elapsed))
482 LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
484 __FUNCTION__, r_sample, t_elapsed);
486 r_sample -= t_elapsed;
488 /* Update RTT estimate by
489 * If (No feedback recv)
492 * R = q * R + (1 - q) * R_sample;
494 * q is a constant, RFC 3448 recomments 0.9
496 if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
497 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
498 hctx->ccid3hctx_rtt = r_sample;
500 hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
503 ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
504 "r_sample=%us\n", dccp_role(sk), sk,
505 hctx->ccid3hctx_rtt, r_sample);
507 /* Update timeout interval */
508 hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
511 /* Update receive rate */
512 hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
514 /* Update loss event rate */
515 if (pinv == ~0 || pinv == 0)
516 hctx->ccid3hctx_p = 0;
518 hctx->ccid3hctx_p = 1000000 / pinv;
520 if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
521 hctx->ccid3hctx_p = TFRC_SMALLEST_P;
522 ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
527 /* unschedule no feedback timer */
528 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
530 /* Update sending rate */
531 ccid3_hc_tx_update_x(sk);
533 /* Update next send time */
534 timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
535 hctx->ccid3hctx_t_ipi);
536 ccid3_calc_new_t_ipi(hctx);
537 timeval_add_usecs(&hctx->ccid3hctx_t_nom,
538 hctx->ccid3hctx_t_ipi);
539 ccid3_calc_new_delta(hctx);
541 /* remove all packets older than the one acked from history */
542 dccp_tx_hist_purge_older(ccid3_tx_hist,
543 &hctx->ccid3hctx_hist, packet);
545 * As we have calculated new ipi, delta, t_nom it is possible that
546 * we now can send a packet, so wake up dccp_wait_for_ccids.
548 sk->sk_write_space(sk);
551 * Schedule no feedback timer to expire in
552 * max(4 * R, 2 * s / X)
554 next_tmout = max(hctx->ccid3hctx_t_rto,
555 2 * usecs_div(hctx->ccid3hctx_s,
558 ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
559 "expire in %lu jiffies (%luus)\n",
561 usecs_to_jiffies(next_tmout), next_tmout);
563 sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
564 jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
567 hctx->ccid3hctx_idle = 1;
570 printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
571 __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
577 static void ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
579 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
581 BUG_ON(hctx == NULL);
583 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
586 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
589 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
590 unsigned char len, u16 idx,
591 unsigned char *value)
594 const struct dccp_sock *dp = dccp_sk(sk);
595 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
596 struct ccid3_options_received *opt_recv;
598 BUG_ON(hctx == NULL);
600 opt_recv = &hctx->ccid3hctx_options_received;
602 if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
603 opt_recv->ccid3or_seqno = dp->dccps_gsr;
604 opt_recv->ccid3or_loss_event_rate = ~0;
605 opt_recv->ccid3or_loss_intervals_idx = 0;
606 opt_recv->ccid3or_loss_intervals_len = 0;
607 opt_recv->ccid3or_receive_rate = 0;
611 case TFRC_OPT_LOSS_EVENT_RATE:
612 if (unlikely(len != 4)) {
613 LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
614 "len for TFRC_OPT_LOSS_EVENT_RATE\n",
615 __FUNCTION__, dccp_role(sk), sk);
618 opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
619 ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
621 opt_recv->ccid3or_loss_event_rate);
624 case TFRC_OPT_LOSS_INTERVALS:
625 opt_recv->ccid3or_loss_intervals_idx = idx;
626 opt_recv->ccid3or_loss_intervals_len = len;
627 ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
629 opt_recv->ccid3or_loss_intervals_idx,
630 opt_recv->ccid3or_loss_intervals_len);
632 case TFRC_OPT_RECEIVE_RATE:
633 if (unlikely(len != 4)) {
634 LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
635 "len for TFRC_OPT_RECEIVE_RATE\n",
636 __FUNCTION__, dccp_role(sk), sk);
639 opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
640 ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
642 opt_recv->ccid3or_receive_rate);
650 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
652 struct dccp_sock *dp = dccp_sk(sk);
653 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
655 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
656 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
657 hctx->ccid3hctx_s = dp->dccps_packet_size;
659 hctx->ccid3hctx_s = TFRC_STD_PACKET_SIZE;
661 /* Set transmission rate to 1 packet per second */
662 hctx->ccid3hctx_x = hctx->ccid3hctx_s;
663 hctx->ccid3hctx_t_rto = USEC_PER_SEC;
664 hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
665 INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
667 hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
668 hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk;
669 init_timer(&hctx->ccid3hctx_no_feedback_timer);
674 static void ccid3_hc_tx_exit(struct sock *sk)
676 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
678 BUG_ON(hctx == NULL);
680 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
681 sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
683 /* Empty packet history */
684 dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
688 * RX Half Connection methods
691 /* TFRC receiver states */
692 enum ccid3_hc_rx_states {
693 TFRC_RSTATE_NO_DATA = 1,
695 TFRC_RSTATE_TERM = 127,
699 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
701 static char *ccid3_rx_state_names[] = {
702 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
703 [TFRC_RSTATE_DATA] = "DATA",
704 [TFRC_RSTATE_TERM] = "TERM",
707 return ccid3_rx_state_names[state];
711 static inline void ccid3_hc_rx_set_state(struct sock *sk,
712 enum ccid3_hc_rx_states state)
714 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
715 enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
717 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
718 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
719 ccid3_rx_state_name(state));
720 WARN_ON(state == oldstate);
721 hcrx->ccid3hcrx_state = state;
724 static void ccid3_hc_rx_send_feedback(struct sock *sk)
726 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
727 struct dccp_sock *dp = dccp_sk(sk);
728 struct dccp_rx_hist_entry *packet;
731 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
733 dccp_timestamp(sk, &now);
735 switch (hcrx->ccid3hcrx_state) {
736 case TFRC_RSTATE_NO_DATA:
737 hcrx->ccid3hcrx_x_recv = 0;
739 case TFRC_RSTATE_DATA: {
740 const u32 delta = timeval_delta(&now,
741 &hcrx->ccid3hcrx_tstamp_last_feedback);
742 hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
747 printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
748 __FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state);
753 packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
754 if (unlikely(packet == NULL)) {
755 LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, no data packet "
757 __FUNCTION__, dccp_role(sk), sk);
761 hcrx->ccid3hcrx_tstamp_last_feedback = now;
762 hcrx->ccid3hcrx_last_counter = packet->dccphrx_ccval;
763 hcrx->ccid3hcrx_seqno_last_counter = packet->dccphrx_seqno;
764 hcrx->ccid3hcrx_bytes_recv = 0;
766 /* Convert to multiples of 10us */
767 hcrx->ccid3hcrx_elapsed_time =
768 timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
769 if (hcrx->ccid3hcrx_p == 0)
770 hcrx->ccid3hcrx_pinv = ~0;
772 hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
773 dp->dccps_hc_rx_insert_options = 1;
777 static void ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
779 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
782 BUG_ON(hcrx == NULL);
784 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
787 DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_last_counter;
789 if (dccp_packet_without_ack(skb))
792 if (hcrx->ccid3hcrx_elapsed_time != 0)
793 dccp_insert_option_elapsed_time(sk, skb,
794 hcrx->ccid3hcrx_elapsed_time);
795 dccp_insert_option_timestamp(sk, skb);
796 x_recv = htonl(hcrx->ccid3hcrx_x_recv);
797 pinv = htonl(hcrx->ccid3hcrx_pinv);
798 dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
799 &pinv, sizeof(pinv));
800 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
801 &x_recv, sizeof(x_recv));
804 /* calculate first loss interval
806 * returns estimated loss interval in usecs */
808 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
810 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
811 struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
812 u32 rtt, delta, x_recv, fval, p, tmp2;
813 struct timeval tstamp = { 0, };
819 list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
821 if (dccp_rx_hist_entry_data_packet(entry)) {
826 tstamp = entry->dccphrx_tstamp;
827 win_count = entry->dccphrx_ccval;
831 interval = win_count - entry->dccphrx_ccval;
833 interval += TFRC_WIN_COUNT_LIMIT;
841 if (unlikely(step == 0)) {
842 LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, packet history "
843 "contains no data packets!\n",
844 __FUNCTION__, dccp_role(sk), sk);
848 if (unlikely(interval == 0)) {
849 LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, Could not find a "
850 "win_count interval > 0. Defaulting to 1\n",
851 __FUNCTION__, dccp_role(sk), sk);
855 rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
856 ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
857 dccp_role(sk), sk, rtt);
861 dccp_timestamp(sk, &tstamp);
862 delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
863 x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);
865 tmp1 = (u64)x_recv * (u64)rtt;
866 do_div(tmp1,10000000);
868 fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
869 /* do not alter order above or you will get overflow on 32 bit */
870 p = tfrc_calc_x_reverse_lookup(fval);
871 ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
872 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
880 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
882 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
884 if (seq_loss != DCCP_MAX_SEQNO + 1 &&
885 list_empty(&hcrx->ccid3hcrx_li_hist)) {
886 struct dccp_li_hist_entry *li_tail;
888 li_tail = dccp_li_hist_interval_new(ccid3_li_hist,
889 &hcrx->ccid3hcrx_li_hist,
893 li_tail->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
895 LIMIT_NETDEBUG(KERN_WARNING "%s: FIXME: find end of "
896 "interval\n", __FUNCTION__);
899 static void ccid3_hc_rx_detect_loss(struct sock *sk)
901 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
903 const u64 seq_loss = dccp_rx_hist_detect_loss(&hcrx->ccid3hcrx_hist,
904 &hcrx->ccid3hcrx_li_hist,
907 ccid3_hc_rx_update_li(sk, seq_loss, win_loss);
910 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
912 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
913 const struct dccp_options_received *opt_recv;
914 struct dccp_rx_hist_entry *packet;
917 u32 p_prev, r_sample, t_elapsed;
920 BUG_ON(hcrx == NULL ||
921 !(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA ||
922 hcrx->ccid3hcrx_state == TFRC_RSTATE_DATA));
924 opt_recv = &dccp_sk(sk)->dccps_options_received;
926 switch (DCCP_SKB_CB(skb)->dccpd_type) {
928 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
930 case DCCP_PKT_DATAACK:
931 if (opt_recv->dccpor_timestamp_echo == 0)
933 p_prev = hcrx->ccid3hcrx_rtt;
934 dccp_timestamp(sk, &now);
935 timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
936 r_sample = timeval_usecs(&now);
937 t_elapsed = opt_recv->dccpor_elapsed_time * 10;
939 if (unlikely(r_sample <= t_elapsed))
940 LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
942 __FUNCTION__, r_sample, t_elapsed);
944 r_sample -= t_elapsed;
946 if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
947 hcrx->ccid3hcrx_rtt = r_sample;
949 hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
952 if (p_prev != hcrx->ccid3hcrx_rtt)
953 ccid3_pr_debug("%s, New RTT=%luus, elapsed time=%u\n",
954 dccp_role(sk), hcrx->ccid3hcrx_rtt,
955 opt_recv->dccpor_elapsed_time);
959 default: /* We're not interested in other packet types, move along */
963 packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
965 if (unlikely(packet == NULL)) {
966 LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, Not enough mem to "
967 "add rx packet to history, consider it lost!\n",
968 __FUNCTION__, dccp_role(sk), sk);
972 win_count = packet->dccphrx_ccval;
974 ins = dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
975 &hcrx->ccid3hcrx_li_hist, packet);
977 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
980 switch (hcrx->ccid3hcrx_state) {
981 case TFRC_RSTATE_NO_DATA:
982 ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial "
985 dccp_state_name(sk->sk_state), skb);
986 ccid3_hc_rx_send_feedback(sk);
987 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
989 case TFRC_RSTATE_DATA:
990 hcrx->ccid3hcrx_bytes_recv += skb->len -
991 dccp_hdr(skb)->dccph_doff * 4;
995 dccp_timestamp(sk, &now);
996 if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
997 hcrx->ccid3hcrx_rtt) {
998 hcrx->ccid3hcrx_tstamp_last_ack = now;
999 ccid3_hc_rx_send_feedback(sk);
1003 printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
1004 __FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state);
1009 /* Dealing with packet loss */
1010 ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n",
1011 dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1013 ccid3_hc_rx_detect_loss(sk);
1014 p_prev = hcrx->ccid3hcrx_p;
1016 /* Calculate loss event rate */
1017 if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1018 u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1020 /* Scaling up by 1000000 as fixed decimal */
1022 hcrx->ccid3hcrx_p = 1000000 / i_mean;
1025 if (hcrx->ccid3hcrx_p > p_prev) {
1026 ccid3_hc_rx_send_feedback(sk);
1031 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1033 struct dccp_sock *dp = dccp_sk(sk);
1034 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1036 ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
1038 if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
1039 dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
1040 hcrx->ccid3hcrx_s = dp->dccps_packet_size;
1042 hcrx->ccid3hcrx_s = TFRC_STD_PACKET_SIZE;
1044 hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1045 INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1046 INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1047 dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1048 hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1049 hcrx->ccid3hcrx_rtt = 5000; /* XXX 5ms for now... */
1053 static void ccid3_hc_rx_exit(struct sock *sk)
1055 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1057 BUG_ON(hcrx == NULL);
1059 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1061 /* Empty packet history */
1062 dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1064 /* Empty loss interval history */
1065 dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1068 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1070 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1072 /* Listen socks doesn't have a private CCID block */
1073 if (sk->sk_state == DCCP_LISTEN)
1076 BUG_ON(hcrx == NULL);
1078 info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1079 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
1080 info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
1083 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1085 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1087 /* Listen socks doesn't have a private CCID block */
1088 if (sk->sk_state == DCCP_LISTEN)
1091 BUG_ON(hctx == NULL);
1093 info->tcpi_rto = hctx->ccid3hctx_t_rto;
1094 info->tcpi_rtt = hctx->ccid3hctx_rtt;
1097 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1098 u32 __user *optval, int __user *optlen)
1100 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1103 /* Listen socks doesn't have a private CCID block */
1104 if (sk->sk_state == DCCP_LISTEN)
1108 case DCCP_SOCKOPT_CCID_RX_INFO:
1109 if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1111 len = sizeof(hcrx->ccid3hcrx_tfrc);
1112 val = &hcrx->ccid3hcrx_tfrc;
1115 return -ENOPROTOOPT;
1118 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1124 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1125 u32 __user *optval, int __user *optlen)
1127 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1130 /* Listen socks doesn't have a private CCID block */
1131 if (sk->sk_state == DCCP_LISTEN)
1135 case DCCP_SOCKOPT_CCID_TX_INFO:
1136 if (len < sizeof(hctx->ccid3hctx_tfrc))
1138 len = sizeof(hctx->ccid3hctx_tfrc);
1139 val = &hctx->ccid3hctx_tfrc;
1142 return -ENOPROTOOPT;
1145 if (put_user(len, optlen) || copy_to_user(optval, val, len))
1151 static struct ccid_operations ccid3 = {
1153 .ccid_name = "ccid3",
1154 .ccid_owner = THIS_MODULE,
1155 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
1156 .ccid_hc_tx_init = ccid3_hc_tx_init,
1157 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
1158 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
1159 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
1160 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
1161 .ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
1162 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
1163 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
1164 .ccid_hc_rx_init = ccid3_hc_rx_init,
1165 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
1166 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1167 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
1168 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
1169 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
1170 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
1171 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
1174 module_param(ccid3_debug, int, 0444);
1175 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1177 static __init int ccid3_module_init(void)
1181 ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1182 if (ccid3_rx_hist == NULL)
1185 ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1186 if (ccid3_tx_hist == NULL)
1189 ccid3_li_hist = dccp_li_hist_new("ccid3");
1190 if (ccid3_li_hist == NULL)
1193 rc = ccid_register(&ccid3);
1195 goto out_free_loss_interval_history;
1199 out_free_loss_interval_history:
1200 dccp_li_hist_delete(ccid3_li_hist);
1201 ccid3_li_hist = NULL;
1203 dccp_tx_hist_delete(ccid3_tx_hist);
1204 ccid3_tx_hist = NULL;
1206 dccp_rx_hist_delete(ccid3_rx_hist);
1207 ccid3_rx_hist = NULL;
1210 module_init(ccid3_module_init);
1212 static __exit void ccid3_module_exit(void)
1214 #ifdef CONFIG_IP_DCCP_UNLOAD_HACK
1216 * Hack to use while developing, so that we get rid of the control
1217 * sock, that is what keeps a refcount on dccp.ko -acme
1219 extern void dccp_ctl_sock_exit(void);
1221 dccp_ctl_sock_exit();
1223 ccid_unregister(&ccid3);
1225 if (ccid3_tx_hist != NULL) {
1226 dccp_tx_hist_delete(ccid3_tx_hist);
1227 ccid3_tx_hist = NULL;
1229 if (ccid3_rx_hist != NULL) {
1230 dccp_rx_hist_delete(ccid3_rx_hist);
1231 ccid3_rx_hist = NULL;
1233 if (ccid3_li_hist != NULL) {
1234 dccp_li_hist_delete(ccid3_li_hist);
1235 ccid3_li_hist = NULL;
1238 module_exit(ccid3_module_exit);
1240 MODULE_AUTHOR("Ian McDonald <iam4@cs.waikato.ac.nz>, "
1241 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1242 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1243 MODULE_LICENSE("GPL");
1244 MODULE_ALIAS("net-dccp-ccid-3");