2 * net/dccp/ccids/ccid2.c
4 * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
6 * Changes to meet Linux coding standards, and DCCP infrastructure fixes.
8 * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 * This implementation should follow RFC 4341
29 * - sequence number wrapping
37 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
38 static int ccid2_debug;
39 #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a)
41 static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
45 struct ccid2_seq *seqp = hctx->ccid2hctx_seqh;
47 /* there is data in the chain */
48 if (seqp != hctx->ccid2hctx_seqt) {
49 seqp = seqp->ccid2s_prev;
51 if (!seqp->ccid2s_acked)
54 while (seqp != hctx->ccid2hctx_seqt) {
55 struct ccid2_seq *prev = seqp->ccid2s_prev;
58 if (!prev->ccid2s_acked)
61 /* packets are sent sequentially */
62 BUG_ON(seqp->ccid2s_seq <= prev->ccid2s_seq);
63 BUG_ON(time_before(seqp->ccid2s_sent,
70 BUG_ON(pipe != hctx->ccid2hctx_pipe);
71 ccid2_pr_debug("len of chain=%d\n", len);
74 seqp = seqp->ccid2s_prev;
76 } while (seqp != hctx->ccid2hctx_seqh);
78 ccid2_pr_debug("total len=%d\n", len);
79 BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN);
82 #define ccid2_pr_debug(format, a...)
83 #define ccid2_hc_tx_check_sanity(hctx)
86 static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx)
88 struct ccid2_seq *seqp;
91 /* check if we have space to preserve the pointer to the buffer */
92 if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) /
93 sizeof(struct ccid2_seq*)))
96 /* allocate buffer and initialize linked list */
97 seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any());
101 for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) {
102 seqp[i].ccid2s_next = &seqp[i + 1];
103 seqp[i + 1].ccid2s_prev = &seqp[i];
105 seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp;
106 seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
108 /* This is the first allocation. Initiate the head and tail. */
109 if (hctx->ccid2hctx_seqbufc == 0)
110 hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp;
112 /* link the existing list with the one we just created */
113 hctx->ccid2hctx_seqh->ccid2s_next = seqp;
114 seqp->ccid2s_prev = hctx->ccid2hctx_seqh;
116 hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
117 seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->ccid2hctx_seqt;
120 /* store the original pointer to the buffer so we can free it */
121 hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp;
122 hctx->ccid2hctx_seqbufc++;
127 static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
129 struct ccid2_hc_tx_sock *hctx;
131 switch (DCCP_SKB_CB(skb)->dccpd_type) {
132 case 0: /* XXX data packets from userland come through like this */
134 case DCCP_PKT_DATAACK:
136 /* No congestion control on other packets */
141 hctx = ccid2_hc_tx_sk(sk);
143 ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe,
144 hctx->ccid2hctx_cwnd);
146 if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) {
147 /* OK we can send... make sure previous packet was sent off */
148 if (!hctx->ccid2hctx_sendwait) {
149 hctx->ccid2hctx_sendwait = 1;
154 return 1; /* XXX CCID should dequeue when ready instead of polling */
157 static void ccid2_change_l_ack_ratio(struct sock *sk, int val)
159 struct dccp_sock *dp = dccp_sk(sk);
161 * XXX I don't really agree with val != 2. If cwnd is 1, ack ratio
162 * should be 1... it shouldn't be allowed to become 2.
166 const struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
167 int max = hctx->ccid2hctx_cwnd / 2;
170 if (hctx->ccid2hctx_cwnd & 1)
177 ccid2_pr_debug("changing local ack ratio to %d\n", val);
179 dp->dccps_l_ack_ratio = val;
182 static void ccid2_change_cwnd(struct ccid2_hc_tx_sock *hctx, int val)
187 /* XXX do we need to change ack ratio? */
188 ccid2_pr_debug("change cwnd to %d\n", val);
191 hctx->ccid2hctx_cwnd = val;
194 static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val)
196 ccid2_pr_debug("change SRTT to %ld\n", val);
197 hctx->ccid2hctx_srtt = val;
200 static void ccid2_change_pipe(struct ccid2_hc_tx_sock *hctx, long val)
202 hctx->ccid2hctx_pipe = val;
205 static void ccid2_start_rto_timer(struct sock *sk);
207 static void ccid2_hc_tx_rto_expire(unsigned long data)
209 struct sock *sk = (struct sock *)data;
210 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
214 if (sock_owned_by_user(sk)) {
215 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
220 ccid2_pr_debug("RTO_EXPIRE\n");
222 ccid2_hc_tx_check_sanity(hctx);
225 hctx->ccid2hctx_rto <<= 1;
227 s = hctx->ccid2hctx_rto / HZ;
229 hctx->ccid2hctx_rto = 60 * HZ;
231 ccid2_start_rto_timer(sk);
233 /* adjust pipe, cwnd etc */
234 ccid2_change_pipe(hctx, 0);
235 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1;
236 if (hctx->ccid2hctx_ssthresh < 2)
237 hctx->ccid2hctx_ssthresh = 2;
238 ccid2_change_cwnd(hctx, 1);
240 /* clear state about stuff we sent */
241 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
242 hctx->ccid2hctx_ssacks = 0;
243 hctx->ccid2hctx_acks = 0;
244 hctx->ccid2hctx_sent = 0;
246 /* clear ack ratio state. */
247 hctx->ccid2hctx_arsent = 0;
248 hctx->ccid2hctx_ackloss = 0;
249 hctx->ccid2hctx_rpseq = 0;
250 hctx->ccid2hctx_rpdupack = -1;
251 ccid2_change_l_ack_ratio(sk, 1);
252 ccid2_hc_tx_check_sanity(hctx);
258 static void ccid2_start_rto_timer(struct sock *sk)
260 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
262 ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
264 BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
265 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
266 jiffies + hctx->ccid2hctx_rto);
269 static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
271 struct dccp_sock *dp = dccp_sk(sk);
272 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
273 struct ccid2_seq *next;
276 ccid2_hc_tx_check_sanity(hctx);
278 BUG_ON(!hctx->ccid2hctx_sendwait);
279 hctx->ccid2hctx_sendwait = 0;
280 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe + 1);
281 BUG_ON(hctx->ccid2hctx_pipe < 0);
283 /* There is an issue. What if another packet is sent between
284 * packet_send() and packet_sent(). Then the sequence number would be
290 hctx->ccid2hctx_seqh->ccid2s_seq = seq;
291 hctx->ccid2hctx_seqh->ccid2s_acked = 0;
292 hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
294 next = hctx->ccid2hctx_seqh->ccid2s_next;
295 /* check if we need to alloc more space */
296 if (next == hctx->ccid2hctx_seqt) {
299 ccid2_pr_debug("allocating more space in history\n");
300 rc = ccid2_hc_tx_alloc_seq(hctx);
301 BUG_ON(rc); /* XXX what do we do? */
303 next = hctx->ccid2hctx_seqh->ccid2s_next;
304 BUG_ON(next == hctx->ccid2hctx_seqt);
306 hctx->ccid2hctx_seqh = next;
308 ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
309 hctx->ccid2hctx_pipe);
311 hctx->ccid2hctx_sent++;
313 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
314 hctx->ccid2hctx_arsent++;
315 /* We had an ack loss in this window... */
316 if (hctx->ccid2hctx_ackloss) {
317 if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
318 hctx->ccid2hctx_arsent = 0;
319 hctx->ccid2hctx_ackloss = 0;
322 /* No acks lost up to now... */
323 /* decrease ack ratio if enough packets were sent */
324 if (dp->dccps_l_ack_ratio > 1) {
325 /* XXX don't calculate denominator each time */
326 int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
327 dp->dccps_l_ack_ratio;
329 denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
331 if (hctx->ccid2hctx_arsent >= denom) {
332 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
333 hctx->ccid2hctx_arsent = 0;
336 /* we can't increase ack ratio further [1] */
337 hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
341 /* setup RTO timer */
342 if (!timer_pending(&hctx->ccid2hctx_rtotimer))
343 ccid2_start_rto_timer(sk);
345 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
346 ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe);
347 ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)seq);
349 struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
351 while (seqp != hctx->ccid2hctx_seqh) {
352 ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
353 (unsigned long long)seqp->ccid2s_seq,
354 seqp->ccid2s_acked, seqp->ccid2s_sent);
355 seqp = seqp->ccid2s_next;
358 ccid2_pr_debug("=========\n");
359 ccid2_hc_tx_check_sanity(hctx);
363 /* XXX Lame code duplication!
364 * returns -1 if none was found.
365 * else returns the next offset to use in the function call.
367 static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
368 unsigned char **vec, unsigned char *veclen)
370 const struct dccp_hdr *dh = dccp_hdr(skb);
371 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
372 unsigned char *opt_ptr;
373 const unsigned char *opt_end = (unsigned char *)dh +
374 (dh->dccph_doff * 4);
375 unsigned char opt, len;
376 unsigned char *value;
381 if (opt_ptr >= opt_end)
384 while (opt_ptr != opt_end) {
389 /* Check if this isn't a single byte option */
390 if (opt > DCCPO_MAX_RESERVED) {
391 if (opt_ptr == opt_end)
392 goto out_invalid_option;
396 goto out_invalid_option;
398 * Remove the type and len fields, leaving
399 * just the value size
405 if (opt_ptr > opt_end)
406 goto out_invalid_option;
410 case DCCPO_ACK_VECTOR_0:
411 case DCCPO_ACK_VECTOR_1:
414 return offset + (opt_ptr - options);
421 DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
425 static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
427 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
429 sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
430 ccid2_pr_debug("deleted RTO timer\n");
433 static inline void ccid2_new_ack(struct sock *sk,
434 struct ccid2_seq *seqp,
435 unsigned int *maxincr)
437 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
440 if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
441 hctx->ccid2hctx_acks = 0;
443 /* We can increase cwnd at most maxincr [ack_ratio/2] */
445 /* increase every 2 acks */
446 hctx->ccid2hctx_ssacks++;
447 if (hctx->ccid2hctx_ssacks == 2) {
448 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd+1);
449 hctx->ccid2hctx_ssacks = 0;
450 *maxincr = *maxincr - 1;
453 /* increased cwnd enough for this single ack */
454 hctx->ccid2hctx_ssacks = 0;
457 hctx->ccid2hctx_ssacks = 0;
458 hctx->ccid2hctx_acks++;
460 if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
461 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd + 1);
462 hctx->ccid2hctx_acks = 0;
467 if (hctx->ccid2hctx_srtt == -1 ||
468 time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) {
469 unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
472 /* first measurement */
473 if (hctx->ccid2hctx_srtt == -1) {
474 ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
476 (unsigned long long)seqp->ccid2s_seq);
477 ccid2_change_srtt(hctx, r);
478 hctx->ccid2hctx_rttvar = r >> 1;
481 long tmp = hctx->ccid2hctx_srtt - r;
488 hctx->ccid2hctx_rttvar *= 3;
489 hctx->ccid2hctx_rttvar >>= 2;
490 hctx->ccid2hctx_rttvar += tmp;
493 srtt = hctx->ccid2hctx_srtt;
498 ccid2_change_srtt(hctx, srtt);
500 s = hctx->ccid2hctx_rttvar << 2;
501 /* clock granularity is 1 when based on jiffies */
504 hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
506 /* must be at least a second */
507 s = hctx->ccid2hctx_rto / HZ;
508 /* DCCP doesn't require this [but I like it cuz my code sux] */
511 hctx->ccid2hctx_rto = HZ;
515 hctx->ccid2hctx_rto = HZ * 60;
517 hctx->ccid2hctx_lastrtt = jiffies;
519 ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
520 hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
521 hctx->ccid2hctx_rto, HZ, r);
522 hctx->ccid2hctx_sent = 0;
525 /* we got a new ack, so re-start RTO timer */
526 ccid2_hc_tx_kill_rto_timer(sk);
527 ccid2_start_rto_timer(sk);
530 static void ccid2_hc_tx_dec_pipe(struct sock *sk)
532 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
534 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe-1);
535 BUG_ON(hctx->ccid2hctx_pipe < 0);
537 if (hctx->ccid2hctx_pipe == 0)
538 ccid2_hc_tx_kill_rto_timer(sk);
541 static void ccid2_congestion_event(struct ccid2_hc_tx_sock *hctx,
542 struct ccid2_seq *seqp)
544 if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
545 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
549 hctx->ccid2hctx_last_cong = jiffies;
551 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd >> 1);
552 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd;
553 if (hctx->ccid2hctx_ssthresh < 2)
554 hctx->ccid2hctx_ssthresh = 2;
557 static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
559 struct dccp_sock *dp = dccp_sk(sk);
560 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
562 struct ccid2_seq *seqp;
563 unsigned char *vector;
564 unsigned char veclen;
567 unsigned int maxincr = 0;
569 ccid2_hc_tx_check_sanity(hctx);
570 /* check reverse path congestion */
571 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
573 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
574 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
577 /* need to bootstrap */
578 if (hctx->ccid2hctx_rpdupack == -1) {
579 hctx->ccid2hctx_rpdupack = 0;
580 hctx->ccid2hctx_rpseq = seqno;
582 /* check if packet is consecutive */
583 if ((hctx->ccid2hctx_rpseq + 1) == seqno)
584 hctx->ccid2hctx_rpseq++;
585 /* it's a later packet */
586 else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
587 hctx->ccid2hctx_rpdupack++;
589 /* check if we got enough dupacks */
590 if (hctx->ccid2hctx_rpdupack >=
591 hctx->ccid2hctx_numdupack) {
592 hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
593 hctx->ccid2hctx_rpseq = 0;
595 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1);
600 /* check forward path congestion */
601 /* still didn't send out new data packets */
602 if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
605 switch (DCCP_SKB_CB(skb)->dccpd_type) {
607 case DCCP_PKT_DATAACK:
613 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
614 if (after48(ackno, hctx->ccid2hctx_high_ack))
615 hctx->ccid2hctx_high_ack = ackno;
617 seqp = hctx->ccid2hctx_seqt;
618 while (before48(seqp->ccid2s_seq, ackno)) {
619 seqp = seqp->ccid2s_next;
620 if (seqp == hctx->ccid2hctx_seqh) {
621 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
626 /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
627 * this single ack. I round up.
630 maxincr = dp->dccps_l_ack_ratio >> 1;
633 /* go through all ack vectors */
634 while ((offset = ccid2_ackvector(sk, skb, offset,
635 &vector, &veclen)) != -1) {
636 /* go through this ack vector */
638 const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
641 dccp_set_seqno(&ackno_end_rl, ackno - rl);
642 ccid2_pr_debug("ackvec start:%llu end:%llu\n",
643 (unsigned long long)ackno,
644 (unsigned long long)ackno_end_rl);
645 /* if the seqno we are analyzing is larger than the
646 * current ackno, then move towards the tail of our
649 while (after48(seqp->ccid2s_seq, ackno)) {
650 if (seqp == hctx->ccid2hctx_seqt) {
654 seqp = seqp->ccid2s_prev;
659 /* check all seqnos in the range of the vector
662 while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
663 const u8 state = *vector &
664 DCCP_ACKVEC_STATE_MASK;
666 /* new packet received or marked */
667 if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
668 !seqp->ccid2s_acked) {
670 DCCP_ACKVEC_STATE_ECN_MARKED) {
671 ccid2_congestion_event(hctx,
674 ccid2_new_ack(sk, seqp,
677 seqp->ccid2s_acked = 1;
678 ccid2_pr_debug("Got ack for %llu\n",
679 (unsigned long long)seqp->ccid2s_seq);
680 ccid2_hc_tx_dec_pipe(sk);
682 if (seqp == hctx->ccid2hctx_seqt) {
686 seqp = seqp->ccid2s_next;
692 dccp_set_seqno(&ackno, ackno_end_rl - 1);
699 /* The state about what is acked should be correct now
700 * Check for NUMDUPACK
702 seqp = hctx->ccid2hctx_seqt;
703 while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) {
704 seqp = seqp->ccid2s_next;
705 if (seqp == hctx->ccid2hctx_seqh) {
706 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
712 if (seqp->ccid2s_acked) {
714 if (done == hctx->ccid2hctx_numdupack)
717 if (seqp == hctx->ccid2hctx_seqt)
719 seqp = seqp->ccid2s_prev;
722 /* If there are at least 3 acknowledgements, anything unacknowledged
723 * below the last sequence number is considered lost
725 if (done == hctx->ccid2hctx_numdupack) {
726 struct ccid2_seq *last_acked = seqp;
728 /* check for lost packets */
730 if (!seqp->ccid2s_acked) {
731 ccid2_pr_debug("Packet lost: %llu\n",
732 (unsigned long long)seqp->ccid2s_seq);
733 /* XXX need to traverse from tail -> head in
734 * order to detect multiple congestion events in
737 ccid2_congestion_event(hctx, seqp);
738 ccid2_hc_tx_dec_pipe(sk);
740 if (seqp == hctx->ccid2hctx_seqt)
742 seqp = seqp->ccid2s_prev;
745 hctx->ccid2hctx_seqt = last_acked;
748 /* trim acked packets in tail */
749 while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
750 if (!hctx->ccid2hctx_seqt->ccid2s_acked)
753 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
756 ccid2_hc_tx_check_sanity(hctx);
759 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
761 struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
763 ccid2_change_cwnd(hctx, 1);
764 /* Initialize ssthresh to infinity. This means that we will exit the
765 * initial slow-start after the first packet loss. This is what we
768 hctx->ccid2hctx_ssthresh = ~0;
769 hctx->ccid2hctx_numdupack = 3;
770 hctx->ccid2hctx_seqbufc = 0;
772 /* XXX init ~ to window size... */
773 if (ccid2_hc_tx_alloc_seq(hctx))
776 hctx->ccid2hctx_sent = 0;
777 hctx->ccid2hctx_rto = 3 * HZ;
778 ccid2_change_srtt(hctx, -1);
779 hctx->ccid2hctx_rttvar = -1;
780 hctx->ccid2hctx_lastrtt = 0;
781 hctx->ccid2hctx_rpdupack = -1;
782 hctx->ccid2hctx_last_cong = jiffies;
783 hctx->ccid2hctx_high_ack = 0;
785 hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
786 hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
787 init_timer(&hctx->ccid2hctx_rtotimer);
789 ccid2_hc_tx_check_sanity(hctx);
793 static void ccid2_hc_tx_exit(struct sock *sk)
795 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
798 ccid2_hc_tx_kill_rto_timer(sk);
800 for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
801 kfree(hctx->ccid2hctx_seqbuf[i]);
802 hctx->ccid2hctx_seqbufc = 0;
805 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
807 const struct dccp_sock *dp = dccp_sk(sk);
808 struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
810 switch (DCCP_SKB_CB(skb)->dccpd_type) {
812 case DCCP_PKT_DATAACK:
813 hcrx->ccid2hcrx_data++;
814 if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
816 hcrx->ccid2hcrx_data = 0;
822 static struct ccid_operations ccid2 = {
823 .ccid_id = DCCPC_CCID2,
824 .ccid_name = "ccid2",
825 .ccid_owner = THIS_MODULE,
826 .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
827 .ccid_hc_tx_init = ccid2_hc_tx_init,
828 .ccid_hc_tx_exit = ccid2_hc_tx_exit,
829 .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
830 .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
831 .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
832 .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
833 .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
836 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
837 module_param(ccid2_debug, bool, 0444);
838 MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
841 static __init int ccid2_module_init(void)
843 return ccid_register(&ccid2);
845 module_init(ccid2_module_init);
847 static __exit void ccid2_module_exit(void)
849 ccid_unregister(&ccid2);
851 module_exit(ccid2_module_exit);
853 MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
854 MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID");
855 MODULE_LICENSE("GPL");
856 MODULE_ALIAS("net-dccp-ccid-2");