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, u32 val)
184 /* XXX do we need to change ack ratio? */
185 hctx->ccid2hctx_cwnd = val? : 1;
186 ccid2_pr_debug("changed cwnd to %u\n", hctx->ccid2hctx_cwnd);
189 static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val)
191 ccid2_pr_debug("change SRTT to %ld\n", val);
192 hctx->ccid2hctx_srtt = val;
195 static void ccid2_change_pipe(struct ccid2_hc_tx_sock *hctx, long val)
197 hctx->ccid2hctx_pipe = val;
200 static void ccid2_start_rto_timer(struct sock *sk);
202 static void ccid2_hc_tx_rto_expire(unsigned long data)
204 struct sock *sk = (struct sock *)data;
205 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
209 if (sock_owned_by_user(sk)) {
210 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
215 ccid2_pr_debug("RTO_EXPIRE\n");
217 ccid2_hc_tx_check_sanity(hctx);
220 hctx->ccid2hctx_rto <<= 1;
222 s = hctx->ccid2hctx_rto / HZ;
224 hctx->ccid2hctx_rto = 60 * HZ;
226 ccid2_start_rto_timer(sk);
228 /* adjust pipe, cwnd etc */
229 ccid2_change_pipe(hctx, 0);
230 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1;
231 if (hctx->ccid2hctx_ssthresh < 2)
232 hctx->ccid2hctx_ssthresh = 2;
233 ccid2_change_cwnd(hctx, 1);
235 /* clear state about stuff we sent */
236 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
237 hctx->ccid2hctx_ssacks = 0;
238 hctx->ccid2hctx_acks = 0;
239 hctx->ccid2hctx_sent = 0;
241 /* clear ack ratio state. */
242 hctx->ccid2hctx_arsent = 0;
243 hctx->ccid2hctx_ackloss = 0;
244 hctx->ccid2hctx_rpseq = 0;
245 hctx->ccid2hctx_rpdupack = -1;
246 ccid2_change_l_ack_ratio(sk, 1);
247 ccid2_hc_tx_check_sanity(hctx);
253 static void ccid2_start_rto_timer(struct sock *sk)
255 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
257 ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
259 BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
260 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
261 jiffies + hctx->ccid2hctx_rto);
264 static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
266 struct dccp_sock *dp = dccp_sk(sk);
267 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
268 struct ccid2_seq *next;
271 ccid2_hc_tx_check_sanity(hctx);
273 BUG_ON(!hctx->ccid2hctx_sendwait);
274 hctx->ccid2hctx_sendwait = 0;
275 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe + 1);
276 BUG_ON(hctx->ccid2hctx_pipe < 0);
278 /* There is an issue. What if another packet is sent between
279 * packet_send() and packet_sent(). Then the sequence number would be
285 hctx->ccid2hctx_seqh->ccid2s_seq = seq;
286 hctx->ccid2hctx_seqh->ccid2s_acked = 0;
287 hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
289 next = hctx->ccid2hctx_seqh->ccid2s_next;
290 /* check if we need to alloc more space */
291 if (next == hctx->ccid2hctx_seqt) {
292 if (ccid2_hc_tx_alloc_seq(hctx)) {
293 DCCP_CRIT("packet history - out of memory!");
294 /* FIXME: find a more graceful way to bail out */
297 next = hctx->ccid2hctx_seqh->ccid2s_next;
298 BUG_ON(next == hctx->ccid2hctx_seqt);
300 hctx->ccid2hctx_seqh = next;
302 ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
303 hctx->ccid2hctx_pipe);
305 hctx->ccid2hctx_sent++;
307 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
308 hctx->ccid2hctx_arsent++;
309 /* We had an ack loss in this window... */
310 if (hctx->ccid2hctx_ackloss) {
311 if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
312 hctx->ccid2hctx_arsent = 0;
313 hctx->ccid2hctx_ackloss = 0;
316 /* No acks lost up to now... */
317 /* decrease ack ratio if enough packets were sent */
318 if (dp->dccps_l_ack_ratio > 1) {
319 /* XXX don't calculate denominator each time */
320 int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
321 dp->dccps_l_ack_ratio;
323 denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
325 if (hctx->ccid2hctx_arsent >= denom) {
326 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
327 hctx->ccid2hctx_arsent = 0;
330 /* we can't increase ack ratio further [1] */
331 hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
335 /* setup RTO timer */
336 if (!timer_pending(&hctx->ccid2hctx_rtotimer))
337 ccid2_start_rto_timer(sk);
339 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
340 ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe);
341 ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)seq);
343 struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
345 while (seqp != hctx->ccid2hctx_seqh) {
346 ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
347 (unsigned long long)seqp->ccid2s_seq,
348 seqp->ccid2s_acked, seqp->ccid2s_sent);
349 seqp = seqp->ccid2s_next;
352 ccid2_pr_debug("=========\n");
353 ccid2_hc_tx_check_sanity(hctx);
357 /* XXX Lame code duplication!
358 * returns -1 if none was found.
359 * else returns the next offset to use in the function call.
361 static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
362 unsigned char **vec, unsigned char *veclen)
364 const struct dccp_hdr *dh = dccp_hdr(skb);
365 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
366 unsigned char *opt_ptr;
367 const unsigned char *opt_end = (unsigned char *)dh +
368 (dh->dccph_doff * 4);
369 unsigned char opt, len;
370 unsigned char *value;
375 if (opt_ptr >= opt_end)
378 while (opt_ptr != opt_end) {
383 /* Check if this isn't a single byte option */
384 if (opt > DCCPO_MAX_RESERVED) {
385 if (opt_ptr == opt_end)
386 goto out_invalid_option;
390 goto out_invalid_option;
392 * Remove the type and len fields, leaving
393 * just the value size
399 if (opt_ptr > opt_end)
400 goto out_invalid_option;
404 case DCCPO_ACK_VECTOR_0:
405 case DCCPO_ACK_VECTOR_1:
408 return offset + (opt_ptr - options);
415 DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
419 static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
421 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
423 sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
424 ccid2_pr_debug("deleted RTO timer\n");
427 static inline void ccid2_new_ack(struct sock *sk,
428 struct ccid2_seq *seqp,
429 unsigned int *maxincr)
431 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
434 if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
435 hctx->ccid2hctx_acks = 0;
437 /* We can increase cwnd at most maxincr [ack_ratio/2] */
439 /* increase every 2 acks */
440 hctx->ccid2hctx_ssacks++;
441 if (hctx->ccid2hctx_ssacks == 2) {
442 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd+1);
443 hctx->ccid2hctx_ssacks = 0;
444 *maxincr = *maxincr - 1;
447 /* increased cwnd enough for this single ack */
448 hctx->ccid2hctx_ssacks = 0;
451 hctx->ccid2hctx_ssacks = 0;
452 hctx->ccid2hctx_acks++;
454 if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
455 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd + 1);
456 hctx->ccid2hctx_acks = 0;
461 if (hctx->ccid2hctx_srtt == -1 ||
462 time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) {
463 unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
466 /* first measurement */
467 if (hctx->ccid2hctx_srtt == -1) {
468 ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
470 (unsigned long long)seqp->ccid2s_seq);
471 ccid2_change_srtt(hctx, r);
472 hctx->ccid2hctx_rttvar = r >> 1;
475 long tmp = hctx->ccid2hctx_srtt - r;
482 hctx->ccid2hctx_rttvar *= 3;
483 hctx->ccid2hctx_rttvar >>= 2;
484 hctx->ccid2hctx_rttvar += tmp;
487 srtt = hctx->ccid2hctx_srtt;
492 ccid2_change_srtt(hctx, srtt);
494 s = hctx->ccid2hctx_rttvar << 2;
495 /* clock granularity is 1 when based on jiffies */
498 hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
500 /* must be at least a second */
501 s = hctx->ccid2hctx_rto / HZ;
502 /* DCCP doesn't require this [but I like it cuz my code sux] */
505 hctx->ccid2hctx_rto = HZ;
509 hctx->ccid2hctx_rto = HZ * 60;
511 hctx->ccid2hctx_lastrtt = jiffies;
513 ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
514 hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
515 hctx->ccid2hctx_rto, HZ, r);
516 hctx->ccid2hctx_sent = 0;
519 /* we got a new ack, so re-start RTO timer */
520 ccid2_hc_tx_kill_rto_timer(sk);
521 ccid2_start_rto_timer(sk);
524 static void ccid2_hc_tx_dec_pipe(struct sock *sk)
526 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
528 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe-1);
529 BUG_ON(hctx->ccid2hctx_pipe < 0);
531 if (hctx->ccid2hctx_pipe == 0)
532 ccid2_hc_tx_kill_rto_timer(sk);
535 static void ccid2_congestion_event(struct ccid2_hc_tx_sock *hctx,
536 struct ccid2_seq *seqp)
538 if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
539 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
543 hctx->ccid2hctx_last_cong = jiffies;
545 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd >> 1);
546 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd;
547 if (hctx->ccid2hctx_ssthresh < 2)
548 hctx->ccid2hctx_ssthresh = 2;
551 static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
553 struct dccp_sock *dp = dccp_sk(sk);
554 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
556 struct ccid2_seq *seqp;
557 unsigned char *vector;
558 unsigned char veclen;
561 unsigned int maxincr = 0;
563 ccid2_hc_tx_check_sanity(hctx);
564 /* check reverse path congestion */
565 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
567 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
568 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
571 /* need to bootstrap */
572 if (hctx->ccid2hctx_rpdupack == -1) {
573 hctx->ccid2hctx_rpdupack = 0;
574 hctx->ccid2hctx_rpseq = seqno;
576 /* check if packet is consecutive */
577 if ((hctx->ccid2hctx_rpseq + 1) == seqno)
578 hctx->ccid2hctx_rpseq++;
579 /* it's a later packet */
580 else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
581 hctx->ccid2hctx_rpdupack++;
583 /* check if we got enough dupacks */
584 if (hctx->ccid2hctx_rpdupack >=
585 hctx->ccid2hctx_numdupack) {
586 hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
587 hctx->ccid2hctx_rpseq = 0;
589 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1);
594 /* check forward path congestion */
595 /* still didn't send out new data packets */
596 if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
599 switch (DCCP_SKB_CB(skb)->dccpd_type) {
601 case DCCP_PKT_DATAACK:
607 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
608 if (after48(ackno, hctx->ccid2hctx_high_ack))
609 hctx->ccid2hctx_high_ack = ackno;
611 seqp = hctx->ccid2hctx_seqt;
612 while (before48(seqp->ccid2s_seq, ackno)) {
613 seqp = seqp->ccid2s_next;
614 if (seqp == hctx->ccid2hctx_seqh) {
615 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
620 /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
621 * this single ack. I round up.
624 maxincr = dp->dccps_l_ack_ratio >> 1;
627 /* go through all ack vectors */
628 while ((offset = ccid2_ackvector(sk, skb, offset,
629 &vector, &veclen)) != -1) {
630 /* go through this ack vector */
632 const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
635 dccp_set_seqno(&ackno_end_rl, ackno - rl);
636 ccid2_pr_debug("ackvec start:%llu end:%llu\n",
637 (unsigned long long)ackno,
638 (unsigned long long)ackno_end_rl);
639 /* if the seqno we are analyzing is larger than the
640 * current ackno, then move towards the tail of our
643 while (after48(seqp->ccid2s_seq, ackno)) {
644 if (seqp == hctx->ccid2hctx_seqt) {
648 seqp = seqp->ccid2s_prev;
653 /* check all seqnos in the range of the vector
656 while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
657 const u8 state = *vector &
658 DCCP_ACKVEC_STATE_MASK;
660 /* new packet received or marked */
661 if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
662 !seqp->ccid2s_acked) {
664 DCCP_ACKVEC_STATE_ECN_MARKED) {
665 ccid2_congestion_event(hctx,
668 ccid2_new_ack(sk, seqp,
671 seqp->ccid2s_acked = 1;
672 ccid2_pr_debug("Got ack for %llu\n",
673 (unsigned long long)seqp->ccid2s_seq);
674 ccid2_hc_tx_dec_pipe(sk);
676 if (seqp == hctx->ccid2hctx_seqt) {
680 seqp = seqp->ccid2s_next;
686 dccp_set_seqno(&ackno, ackno_end_rl - 1);
693 /* The state about what is acked should be correct now
694 * Check for NUMDUPACK
696 seqp = hctx->ccid2hctx_seqt;
697 while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) {
698 seqp = seqp->ccid2s_next;
699 if (seqp == hctx->ccid2hctx_seqh) {
700 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
706 if (seqp->ccid2s_acked) {
708 if (done == hctx->ccid2hctx_numdupack)
711 if (seqp == hctx->ccid2hctx_seqt)
713 seqp = seqp->ccid2s_prev;
716 /* If there are at least 3 acknowledgements, anything unacknowledged
717 * below the last sequence number is considered lost
719 if (done == hctx->ccid2hctx_numdupack) {
720 struct ccid2_seq *last_acked = seqp;
722 /* check for lost packets */
724 if (!seqp->ccid2s_acked) {
725 ccid2_pr_debug("Packet lost: %llu\n",
726 (unsigned long long)seqp->ccid2s_seq);
727 /* XXX need to traverse from tail -> head in
728 * order to detect multiple congestion events in
731 ccid2_congestion_event(hctx, seqp);
732 ccid2_hc_tx_dec_pipe(sk);
734 if (seqp == hctx->ccid2hctx_seqt)
736 seqp = seqp->ccid2s_prev;
739 hctx->ccid2hctx_seqt = last_acked;
742 /* trim acked packets in tail */
743 while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
744 if (!hctx->ccid2hctx_seqt->ccid2s_acked)
747 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
750 ccid2_hc_tx_check_sanity(hctx);
753 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
755 struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
757 ccid2_change_cwnd(hctx, 1);
758 /* Initialize ssthresh to infinity. This means that we will exit the
759 * initial slow-start after the first packet loss. This is what we
762 hctx->ccid2hctx_ssthresh = ~0;
763 hctx->ccid2hctx_numdupack = 3;
764 hctx->ccid2hctx_seqbufc = 0;
766 /* XXX init ~ to window size... */
767 if (ccid2_hc_tx_alloc_seq(hctx))
770 hctx->ccid2hctx_sent = 0;
771 hctx->ccid2hctx_rto = 3 * HZ;
772 ccid2_change_srtt(hctx, -1);
773 hctx->ccid2hctx_rttvar = -1;
774 hctx->ccid2hctx_lastrtt = 0;
775 hctx->ccid2hctx_rpdupack = -1;
776 hctx->ccid2hctx_last_cong = jiffies;
777 hctx->ccid2hctx_high_ack = 0;
779 hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
780 hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
781 init_timer(&hctx->ccid2hctx_rtotimer);
783 ccid2_hc_tx_check_sanity(hctx);
787 static void ccid2_hc_tx_exit(struct sock *sk)
789 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
792 ccid2_hc_tx_kill_rto_timer(sk);
794 for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
795 kfree(hctx->ccid2hctx_seqbuf[i]);
796 hctx->ccid2hctx_seqbufc = 0;
799 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
801 const struct dccp_sock *dp = dccp_sk(sk);
802 struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
804 switch (DCCP_SKB_CB(skb)->dccpd_type) {
806 case DCCP_PKT_DATAACK:
807 hcrx->ccid2hcrx_data++;
808 if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
810 hcrx->ccid2hcrx_data = 0;
816 static struct ccid_operations ccid2 = {
817 .ccid_id = DCCPC_CCID2,
818 .ccid_name = "ccid2",
819 .ccid_owner = THIS_MODULE,
820 .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
821 .ccid_hc_tx_init = ccid2_hc_tx_init,
822 .ccid_hc_tx_exit = ccid2_hc_tx_exit,
823 .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
824 .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
825 .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
826 .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
827 .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
830 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
831 module_param(ccid2_debug, bool, 0444);
832 MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
835 static __init int ccid2_module_init(void)
837 return ccid_register(&ccid2);
839 module_init(ccid2_module_init);
841 static __exit void ccid2_module_exit(void)
843 ccid_unregister(&ccid2);
845 module_exit(ccid2_module_exit);
847 MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
848 MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID");
849 MODULE_LICENSE("GPL");
850 MODULE_ALIAS("net-dccp-ccid-2");