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, int num,
89 struct ccid2_seq *seqp;
92 /* check if we have space to preserve the pointer to the buffer */
93 if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) /
94 sizeof(struct ccid2_seq*)))
97 /* allocate buffer and initialize linked list */
98 seqp = kmalloc(sizeof(*seqp) * num, gfp);
102 for (i = 0; i < (num - 1); i++) {
103 seqp[i].ccid2s_next = &seqp[i + 1];
104 seqp[i + 1].ccid2s_prev = &seqp[i];
106 seqp[num - 1].ccid2s_next = seqp;
107 seqp->ccid2s_prev = &seqp[num - 1];
109 /* This is the first allocation. Initiate the head and tail. */
110 if (hctx->ccid2hctx_seqbufc == 0)
111 hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp;
113 /* link the existing list with the one we just created */
114 hctx->ccid2hctx_seqh->ccid2s_next = seqp;
115 seqp->ccid2s_prev = hctx->ccid2hctx_seqh;
117 hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[num - 1];
118 seqp[num - 1].ccid2s_next = hctx->ccid2hctx_seqt;
121 /* store the original pointer to the buffer so we can free it */
122 hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp;
123 hctx->ccid2hctx_seqbufc++;
128 static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
130 struct ccid2_hc_tx_sock *hctx;
132 switch (DCCP_SKB_CB(skb)->dccpd_type) {
133 case 0: /* XXX data packets from userland come through like this */
135 case DCCP_PKT_DATAACK:
137 /* No congestion control on other packets */
142 hctx = ccid2_hc_tx_sk(sk);
144 ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe,
145 hctx->ccid2hctx_cwnd);
147 if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) {
148 /* OK we can send... make sure previous packet was sent off */
149 if (!hctx->ccid2hctx_sendwait) {
150 hctx->ccid2hctx_sendwait = 1;
155 return 1; /* XXX CCID should dequeue when ready instead of polling */
158 static void ccid2_change_l_ack_ratio(struct sock *sk, int val)
160 struct dccp_sock *dp = dccp_sk(sk);
162 * XXX I don't really agree with val != 2. If cwnd is 1, ack ratio
163 * should be 1... it shouldn't be allowed to become 2.
167 const struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
168 int max = hctx->ccid2hctx_cwnd / 2;
171 if (hctx->ccid2hctx_cwnd & 1)
178 ccid2_pr_debug("changing local ack ratio to %d\n", val);
180 dp->dccps_l_ack_ratio = val;
183 static void ccid2_change_cwnd(struct ccid2_hc_tx_sock *hctx, int val)
188 /* XXX do we need to change ack ratio? */
189 ccid2_pr_debug("change cwnd to %d\n", val);
192 hctx->ccid2hctx_cwnd = val;
195 static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val)
197 ccid2_pr_debug("change SRTT to %ld\n", val);
198 hctx->ccid2hctx_srtt = val;
201 static void ccid2_change_pipe(struct ccid2_hc_tx_sock *hctx, long val)
203 hctx->ccid2hctx_pipe = val;
206 static void ccid2_start_rto_timer(struct sock *sk);
208 static void ccid2_hc_tx_rto_expire(unsigned long data)
210 struct sock *sk = (struct sock *)data;
211 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
215 if (sock_owned_by_user(sk)) {
216 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
221 ccid2_pr_debug("RTO_EXPIRE\n");
223 ccid2_hc_tx_check_sanity(hctx);
226 hctx->ccid2hctx_rto <<= 1;
228 s = hctx->ccid2hctx_rto / HZ;
230 hctx->ccid2hctx_rto = 60 * HZ;
232 ccid2_start_rto_timer(sk);
234 /* adjust pipe, cwnd etc */
235 ccid2_change_pipe(hctx, 0);
236 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1;
237 if (hctx->ccid2hctx_ssthresh < 2)
238 hctx->ccid2hctx_ssthresh = 2;
239 ccid2_change_cwnd(hctx, 1);
241 /* clear state about stuff we sent */
242 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
243 hctx->ccid2hctx_ssacks = 0;
244 hctx->ccid2hctx_acks = 0;
245 hctx->ccid2hctx_sent = 0;
247 /* clear ack ratio state. */
248 hctx->ccid2hctx_arsent = 0;
249 hctx->ccid2hctx_ackloss = 0;
250 hctx->ccid2hctx_rpseq = 0;
251 hctx->ccid2hctx_rpdupack = -1;
252 ccid2_change_l_ack_ratio(sk, 1);
253 ccid2_hc_tx_check_sanity(hctx);
259 static void ccid2_start_rto_timer(struct sock *sk)
261 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
263 ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
265 BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
266 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
267 jiffies + hctx->ccid2hctx_rto);
270 static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
272 struct dccp_sock *dp = dccp_sk(sk);
273 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
274 struct ccid2_seq *next;
277 ccid2_hc_tx_check_sanity(hctx);
279 BUG_ON(!hctx->ccid2hctx_sendwait);
280 hctx->ccid2hctx_sendwait = 0;
281 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe + 1);
282 BUG_ON(hctx->ccid2hctx_pipe < 0);
284 /* There is an issue. What if another packet is sent between
285 * packet_send() and packet_sent(). Then the sequence number would be
291 hctx->ccid2hctx_seqh->ccid2s_seq = seq;
292 hctx->ccid2hctx_seqh->ccid2s_acked = 0;
293 hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
295 next = hctx->ccid2hctx_seqh->ccid2s_next;
296 /* check if we need to alloc more space */
297 if (next == hctx->ccid2hctx_seqt) {
300 ccid2_pr_debug("allocating more space in history\n");
301 rc = ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, gfp_any());
302 BUG_ON(rc); /* XXX what do we do? */
304 next = hctx->ccid2hctx_seqh->ccid2s_next;
305 BUG_ON(next == hctx->ccid2hctx_seqt);
307 hctx->ccid2hctx_seqh = next;
309 ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
310 hctx->ccid2hctx_pipe);
312 hctx->ccid2hctx_sent++;
314 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
315 hctx->ccid2hctx_arsent++;
316 /* We had an ack loss in this window... */
317 if (hctx->ccid2hctx_ackloss) {
318 if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
319 hctx->ccid2hctx_arsent = 0;
320 hctx->ccid2hctx_ackloss = 0;
323 /* No acks lost up to now... */
324 /* decrease ack ratio if enough packets were sent */
325 if (dp->dccps_l_ack_ratio > 1) {
326 /* XXX don't calculate denominator each time */
327 int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
328 dp->dccps_l_ack_ratio;
330 denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
332 if (hctx->ccid2hctx_arsent >= denom) {
333 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
334 hctx->ccid2hctx_arsent = 0;
337 /* we can't increase ack ratio further [1] */
338 hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
342 /* setup RTO timer */
343 if (!timer_pending(&hctx->ccid2hctx_rtotimer))
344 ccid2_start_rto_timer(sk);
346 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
347 ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe);
348 ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)seq);
350 struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
352 while (seqp != hctx->ccid2hctx_seqh) {
353 ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
354 (unsigned long long)seqp->ccid2s_seq,
355 seqp->ccid2s_acked, seqp->ccid2s_sent);
356 seqp = seqp->ccid2s_next;
359 ccid2_pr_debug("=========\n");
360 ccid2_hc_tx_check_sanity(hctx);
364 /* XXX Lame code duplication!
365 * returns -1 if none was found.
366 * else returns the next offset to use in the function call.
368 static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
369 unsigned char **vec, unsigned char *veclen)
371 const struct dccp_hdr *dh = dccp_hdr(skb);
372 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
373 unsigned char *opt_ptr;
374 const unsigned char *opt_end = (unsigned char *)dh +
375 (dh->dccph_doff * 4);
376 unsigned char opt, len;
377 unsigned char *value;
382 if (opt_ptr >= opt_end)
385 while (opt_ptr != opt_end) {
390 /* Check if this isn't a single byte option */
391 if (opt > DCCPO_MAX_RESERVED) {
392 if (opt_ptr == opt_end)
393 goto out_invalid_option;
397 goto out_invalid_option;
399 * Remove the type and len fields, leaving
400 * just the value size
406 if (opt_ptr > opt_end)
407 goto out_invalid_option;
411 case DCCPO_ACK_VECTOR_0:
412 case DCCPO_ACK_VECTOR_1:
415 return offset + (opt_ptr - options);
422 DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
426 static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
428 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
430 sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
431 ccid2_pr_debug("deleted RTO timer\n");
434 static inline void ccid2_new_ack(struct sock *sk,
435 struct ccid2_seq *seqp,
436 unsigned int *maxincr)
438 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
441 if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
442 hctx->ccid2hctx_acks = 0;
444 /* We can increase cwnd at most maxincr [ack_ratio/2] */
446 /* increase every 2 acks */
447 hctx->ccid2hctx_ssacks++;
448 if (hctx->ccid2hctx_ssacks == 2) {
449 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd+1);
450 hctx->ccid2hctx_ssacks = 0;
451 *maxincr = *maxincr - 1;
454 /* increased cwnd enough for this single ack */
455 hctx->ccid2hctx_ssacks = 0;
458 hctx->ccid2hctx_ssacks = 0;
459 hctx->ccid2hctx_acks++;
461 if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
462 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd + 1);
463 hctx->ccid2hctx_acks = 0;
468 if (hctx->ccid2hctx_srtt == -1 ||
469 time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) {
470 unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
473 /* first measurement */
474 if (hctx->ccid2hctx_srtt == -1) {
475 ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
477 (unsigned long long)seqp->ccid2s_seq);
478 ccid2_change_srtt(hctx, r);
479 hctx->ccid2hctx_rttvar = r >> 1;
482 long tmp = hctx->ccid2hctx_srtt - r;
489 hctx->ccid2hctx_rttvar *= 3;
490 hctx->ccid2hctx_rttvar >>= 2;
491 hctx->ccid2hctx_rttvar += tmp;
494 srtt = hctx->ccid2hctx_srtt;
499 ccid2_change_srtt(hctx, srtt);
501 s = hctx->ccid2hctx_rttvar << 2;
502 /* clock granularity is 1 when based on jiffies */
505 hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
507 /* must be at least a second */
508 s = hctx->ccid2hctx_rto / HZ;
509 /* DCCP doesn't require this [but I like it cuz my code sux] */
512 hctx->ccid2hctx_rto = HZ;
516 hctx->ccid2hctx_rto = HZ * 60;
518 hctx->ccid2hctx_lastrtt = jiffies;
520 ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
521 hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
522 hctx->ccid2hctx_rto, HZ, r);
523 hctx->ccid2hctx_sent = 0;
526 /* we got a new ack, so re-start RTO timer */
527 ccid2_hc_tx_kill_rto_timer(sk);
528 ccid2_start_rto_timer(sk);
531 static void ccid2_hc_tx_dec_pipe(struct sock *sk)
533 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
535 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe-1);
536 BUG_ON(hctx->ccid2hctx_pipe < 0);
538 if (hctx->ccid2hctx_pipe == 0)
539 ccid2_hc_tx_kill_rto_timer(sk);
542 static void ccid2_congestion_event(struct ccid2_hc_tx_sock *hctx,
543 struct ccid2_seq *seqp)
545 if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
546 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
550 hctx->ccid2hctx_last_cong = jiffies;
552 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd >> 1);
553 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd;
554 if (hctx->ccid2hctx_ssthresh < 2)
555 hctx->ccid2hctx_ssthresh = 2;
558 static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
560 struct dccp_sock *dp = dccp_sk(sk);
561 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
563 struct ccid2_seq *seqp;
564 unsigned char *vector;
565 unsigned char veclen;
568 unsigned int maxincr = 0;
570 ccid2_hc_tx_check_sanity(hctx);
571 /* check reverse path congestion */
572 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
574 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
575 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
578 /* need to bootstrap */
579 if (hctx->ccid2hctx_rpdupack == -1) {
580 hctx->ccid2hctx_rpdupack = 0;
581 hctx->ccid2hctx_rpseq = seqno;
583 /* check if packet is consecutive */
584 if ((hctx->ccid2hctx_rpseq + 1) == seqno)
585 hctx->ccid2hctx_rpseq++;
586 /* it's a later packet */
587 else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
588 hctx->ccid2hctx_rpdupack++;
590 /* check if we got enough dupacks */
591 if (hctx->ccid2hctx_rpdupack >=
592 hctx->ccid2hctx_numdupack) {
593 hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
594 hctx->ccid2hctx_rpseq = 0;
596 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1);
601 /* check forward path congestion */
602 /* still didn't send out new data packets */
603 if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
606 switch (DCCP_SKB_CB(skb)->dccpd_type) {
608 case DCCP_PKT_DATAACK:
614 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
615 if (after48(ackno, hctx->ccid2hctx_high_ack))
616 hctx->ccid2hctx_high_ack = ackno;
618 seqp = hctx->ccid2hctx_seqt;
619 while (before48(seqp->ccid2s_seq, ackno)) {
620 seqp = seqp->ccid2s_next;
621 if (seqp == hctx->ccid2hctx_seqh) {
622 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
627 /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
628 * this single ack. I round up.
631 maxincr = dp->dccps_l_ack_ratio >> 1;
634 /* go through all ack vectors */
635 while ((offset = ccid2_ackvector(sk, skb, offset,
636 &vector, &veclen)) != -1) {
637 /* go through this ack vector */
639 const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
642 dccp_set_seqno(&ackno_end_rl, ackno - rl);
643 ccid2_pr_debug("ackvec start:%llu end:%llu\n",
644 (unsigned long long)ackno,
645 (unsigned long long)ackno_end_rl);
646 /* if the seqno we are analyzing is larger than the
647 * current ackno, then move towards the tail of our
650 while (after48(seqp->ccid2s_seq, ackno)) {
651 if (seqp == hctx->ccid2hctx_seqt) {
655 seqp = seqp->ccid2s_prev;
660 /* check all seqnos in the range of the vector
663 while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
664 const u8 state = *vector &
665 DCCP_ACKVEC_STATE_MASK;
667 /* new packet received or marked */
668 if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
669 !seqp->ccid2s_acked) {
671 DCCP_ACKVEC_STATE_ECN_MARKED) {
672 ccid2_congestion_event(hctx,
675 ccid2_new_ack(sk, seqp,
678 seqp->ccid2s_acked = 1;
679 ccid2_pr_debug("Got ack for %llu\n",
680 (unsigned long long)seqp->ccid2s_seq);
681 ccid2_hc_tx_dec_pipe(sk);
683 if (seqp == hctx->ccid2hctx_seqt) {
687 seqp = seqp->ccid2s_next;
693 dccp_set_seqno(&ackno, ackno_end_rl - 1);
700 /* The state about what is acked should be correct now
701 * Check for NUMDUPACK
703 seqp = hctx->ccid2hctx_seqt;
704 while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) {
705 seqp = seqp->ccid2s_next;
706 if (seqp == hctx->ccid2hctx_seqh) {
707 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
713 if (seqp->ccid2s_acked) {
715 if (done == hctx->ccid2hctx_numdupack)
718 if (seqp == hctx->ccid2hctx_seqt)
720 seqp = seqp->ccid2s_prev;
723 /* If there are at least 3 acknowledgements, anything unacknowledged
724 * below the last sequence number is considered lost
726 if (done == hctx->ccid2hctx_numdupack) {
727 struct ccid2_seq *last_acked = seqp;
729 /* check for lost packets */
731 if (!seqp->ccid2s_acked) {
732 ccid2_pr_debug("Packet lost: %llu\n",
733 (unsigned long long)seqp->ccid2s_seq);
734 /* XXX need to traverse from tail -> head in
735 * order to detect multiple congestion events in
738 ccid2_congestion_event(hctx, seqp);
739 ccid2_hc_tx_dec_pipe(sk);
741 if (seqp == hctx->ccid2hctx_seqt)
743 seqp = seqp->ccid2s_prev;
746 hctx->ccid2hctx_seqt = last_acked;
749 /* trim acked packets in tail */
750 while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
751 if (!hctx->ccid2hctx_seqt->ccid2s_acked)
754 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
757 ccid2_hc_tx_check_sanity(hctx);
760 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
762 struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
764 ccid2_change_cwnd(hctx, 1);
765 /* Initialize ssthresh to infinity. This means that we will exit the
766 * initial slow-start after the first packet loss. This is what we
769 hctx->ccid2hctx_ssthresh = ~0;
770 hctx->ccid2hctx_numdupack = 3;
771 hctx->ccid2hctx_seqbufc = 0;
773 /* XXX init ~ to window size... */
774 if (ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, GFP_ATOMIC) != 0)
777 hctx->ccid2hctx_sent = 0;
778 hctx->ccid2hctx_rto = 3 * HZ;
779 ccid2_change_srtt(hctx, -1);
780 hctx->ccid2hctx_rttvar = -1;
781 hctx->ccid2hctx_lastrtt = 0;
782 hctx->ccid2hctx_rpdupack = -1;
783 hctx->ccid2hctx_last_cong = jiffies;
784 hctx->ccid2hctx_high_ack = 0;
786 hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
787 hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
788 init_timer(&hctx->ccid2hctx_rtotimer);
790 ccid2_hc_tx_check_sanity(hctx);
794 static void ccid2_hc_tx_exit(struct sock *sk)
796 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
799 ccid2_hc_tx_kill_rto_timer(sk);
801 for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
802 kfree(hctx->ccid2hctx_seqbuf[i]);
803 hctx->ccid2hctx_seqbufc = 0;
806 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
808 const struct dccp_sock *dp = dccp_sk(sk);
809 struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
811 switch (DCCP_SKB_CB(skb)->dccpd_type) {
813 case DCCP_PKT_DATAACK:
814 hcrx->ccid2hcrx_data++;
815 if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
817 hcrx->ccid2hcrx_data = 0;
823 static struct ccid_operations ccid2 = {
824 .ccid_id = DCCPC_CCID2,
825 .ccid_name = "ccid2",
826 .ccid_owner = THIS_MODULE,
827 .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
828 .ccid_hc_tx_init = ccid2_hc_tx_init,
829 .ccid_hc_tx_exit = ccid2_hc_tx_exit,
830 .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
831 .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
832 .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
833 .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
834 .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
837 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
838 module_param(ccid2_debug, int, 0444);
839 MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
842 static __init int ccid2_module_init(void)
844 return ccid_register(&ccid2);
846 module_init(ccid2_module_init);
848 static __exit void ccid2_module_exit(void)
850 ccid_unregister(&ccid2);
852 module_exit(ccid2_module_exit);
854 MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
855 MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID");
856 MODULE_LICENSE("GPL");
857 MODULE_ALIAS("net-dccp-ccid-2");