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allow coexistance of N build and AC build.
[tomato.git] / release / src-rt-6.x / linux / linux-2.6 / net / dccp / ccids / ccid2.c
blobd29b88fe723cad5f0dc07d7d2158fac7c214c1b5
1 /*
2 * net/dccp/ccids/ccid2.c
3 *
4 * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
5 *
6 * Changes to meet Linux coding standards, and DCCP infrastructure fixes.
7 *
8 * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
9 *
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.
14 *
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.
19 *
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.
23 */
24
25 /*
26 * This implementation should follow RFC 4341
27 *
28 * BUGS:
29 * - sequence number wrapping
30 */
31
32 #include "../ccid.h"
33 #include "../dccp.h"
34 #include "ccid2.h"
35
36
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)
40
41 static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
42 {
43 int len = 0;
44 int pipe = 0;
45 struct ccid2_seq *seqp = hctx->ccid2hctx_seqh;
46
47 /* there is data in the chain */
48 if (seqp != hctx->ccid2hctx_seqt) {
49 seqp = seqp->ccid2s_prev;
50 len++;
51 if (!seqp->ccid2s_acked)
52 pipe++;
53
54 while (seqp != hctx->ccid2hctx_seqt) {
55 struct ccid2_seq *prev = seqp->ccid2s_prev;
56
57 len++;
58 if (!prev->ccid2s_acked)
59 pipe++;
60
61 /* packets are sent sequentially */
62 BUG_ON(seqp->ccid2s_seq <= prev->ccid2s_seq);
63 BUG_ON(time_before(seqp->ccid2s_sent,
64 prev->ccid2s_sent));
65
66 seqp = prev;
67 }
68 }
69
70 BUG_ON(pipe != hctx->ccid2hctx_pipe);
71 ccid2_pr_debug("len of chain=%d\n", len);
72
73 do {
74 seqp = seqp->ccid2s_prev;
75 len++;
76 } while (seqp != hctx->ccid2hctx_seqh);
77
78 ccid2_pr_debug("total len=%d\n", len);
79 BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN);
80 }
81 #else
82 #define ccid2_pr_debug(format, a...)
83 #define ccid2_hc_tx_check_sanity(hctx)
84 #endif
85
86 static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx, int num,
87 gfp_t gfp)
88 {
89 struct ccid2_seq *seqp;
90 int i;
91
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*)))
95 return -ENOMEM;
96
97 /* allocate buffer and initialize linked list */
98 seqp = kmalloc(sizeof(*seqp) * num, gfp);
99 if (seqp == NULL)
100 return -ENOMEM;
101
102 for (i = 0; i < (num - 1); i++) {
103 seqp[i].ccid2s_next = &seqp[i + 1];
104 seqp[i + 1].ccid2s_prev = &seqp[i];
105 }
106 seqp[num - 1].ccid2s_next = seqp;
107 seqp->ccid2s_prev = &seqp[num - 1];
108
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;
112 else {
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;
116
117 hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[num - 1];
118 seqp[num - 1].ccid2s_next = hctx->ccid2hctx_seqt;
119 }
120
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++;
124
125 return 0;
126 }
127
128 static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
129 {
130 struct ccid2_hc_tx_sock *hctx;
131
132 switch (DCCP_SKB_CB(skb)->dccpd_type) {
133 case 0: /* XXX data packets from userland come through like this */
134 case DCCP_PKT_DATA:
135 case DCCP_PKT_DATAACK:
136 break;
137 /* No congestion control on other packets */
138 default:
139 return 0;
140 }
141
142 hctx = ccid2_hc_tx_sk(sk);
143
144 ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe,
145 hctx->ccid2hctx_cwnd);
146
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;
151 return 0;
152 }
153 }
154
155 return 1; /* XXX CCID should dequeue when ready instead of polling */
156 }
157
158 static void ccid2_change_l_ack_ratio(struct sock *sk, int val)
159 {
160 struct dccp_sock *dp = dccp_sk(sk);
161 /*
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.
164 * -sorbo.
165 */
166 if (val != 2) {
167 const struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
168 int max = hctx->ccid2hctx_cwnd / 2;
169
170 /* round up */
171 if (hctx->ccid2hctx_cwnd & 1)
172 max++;
173
174 if (val > max)
175 val = max;
176 }
177
178 ccid2_pr_debug("changing local ack ratio to %d\n", val);
179 WARN_ON(val <= 0);
180 dp->dccps_l_ack_ratio = val;
181 }
182
183 static void ccid2_change_cwnd(struct ccid2_hc_tx_sock *hctx, int val)
184 {
185 if (val == 0)
186 val = 1;
187
188 /* XXX do we need to change ack ratio? */
189 ccid2_pr_debug("change cwnd to %d\n", val);
190
191 BUG_ON(val < 1);
192 hctx->ccid2hctx_cwnd = val;
193 }
194
195 static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val)
196 {
197 ccid2_pr_debug("change SRTT to %ld\n", val);
198 hctx->ccid2hctx_srtt = val;
199 }
200
201 static void ccid2_change_pipe(struct ccid2_hc_tx_sock *hctx, long val)
202 {
203 hctx->ccid2hctx_pipe = val;
204 }
205
206 static void ccid2_start_rto_timer(struct sock *sk);
207
208 static void ccid2_hc_tx_rto_expire(unsigned long data)
209 {
210 struct sock *sk = (struct sock *)data;
211 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
212 long s;
213
214 bh_lock_sock(sk);
215 if (sock_owned_by_user(sk)) {
216 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
217 jiffies + HZ / 5);
218 goto out;
219 }
220
221 ccid2_pr_debug("RTO_EXPIRE\n");
222
223 ccid2_hc_tx_check_sanity(hctx);
224
225 /* back-off timer */
226 hctx->ccid2hctx_rto <<= 1;
227
228 s = hctx->ccid2hctx_rto / HZ;
229 if (s > 60)
230 hctx->ccid2hctx_rto = 60 * HZ;
231
232 ccid2_start_rto_timer(sk);
233
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);
240
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;
246
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);
254 out:
255 bh_unlock_sock(sk);
256 sock_put(sk);
257 }
258
259 static void ccid2_start_rto_timer(struct sock *sk)
260 {
261 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
262
263 ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
264
265 BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
266 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
267 jiffies + hctx->ccid2hctx_rto);
268 }
269
270 static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
271 {
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;
275 u64 seq;
276
277 ccid2_hc_tx_check_sanity(hctx);
278
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);
283
284 /* There is an issue. What if another packet is sent between
285 * packet_send() and packet_sent(). Then the sequence number would be
286 * wrong.
287 * -sorbo.
288 */
289 seq = dp->dccps_gss;
290
291 hctx->ccid2hctx_seqh->ccid2s_seq = seq;
292 hctx->ccid2hctx_seqh->ccid2s_acked = 0;
293 hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
294
295 next = hctx->ccid2hctx_seqh->ccid2s_next;
296 /* check if we need to alloc more space */
297 if (next == hctx->ccid2hctx_seqt) {
298 int rc;
299
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? */
303
304 next = hctx->ccid2hctx_seqh->ccid2s_next;
305 BUG_ON(next == hctx->ccid2hctx_seqt);
306 }
307 hctx->ccid2hctx_seqh = next;
308
309 ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
310 hctx->ccid2hctx_pipe);
311
312 hctx->ccid2hctx_sent++;
313
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;
321 }
322 } else {
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;
329
330 denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
331
332 if (hctx->ccid2hctx_arsent >= denom) {
333 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
334 hctx->ccid2hctx_arsent = 0;
335 }
336 } else {
337 /* we can't increase ack ratio further [1] */
338 hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
339 }
340 }
341
342 /* setup RTO timer */
343 if (!timer_pending(&hctx->ccid2hctx_rtotimer))
344 ccid2_start_rto_timer(sk);
345
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);
349 do {
350 struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
351
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;
357 }
358 } while (0);
359 ccid2_pr_debug("=========\n");
360 ccid2_hc_tx_check_sanity(hctx);
361 #endif
362 }
363
364 /* XXX Lame code duplication!
365 * returns -1 if none was found.
366 * else returns the next offset to use in the function call.
367 */
368 static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
369 unsigned char **vec, unsigned char *veclen)
370 {
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;
378
379 BUG_ON(offset < 0);
380 options += offset;
381 opt_ptr = options;
382 if (opt_ptr >= opt_end)
383 return -1;
384
385 while (opt_ptr != opt_end) {
386 opt = *opt_ptr++;
387 len = 0;
388 value = NULL;
389
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;
394
395 len = *opt_ptr++;
396 if (len < 3)
397 goto out_invalid_option;
398 /*
399 * Remove the type and len fields, leaving
400 * just the value size
401 */
402 len -= 2;
403 value = opt_ptr;
404 opt_ptr += len;
405
406 if (opt_ptr > opt_end)
407 goto out_invalid_option;
408 }
409
410 switch (opt) {
411 case DCCPO_ACK_VECTOR_0:
412 case DCCPO_ACK_VECTOR_1:
413 *vec = value;
414 *veclen = len;
415 return offset + (opt_ptr - options);
416 }
417 }
418
419 return -1;
420
421 out_invalid_option:
422 DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
423 return -1;
424 }
425
426 static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
427 {
428 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
429
430 sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
431 ccid2_pr_debug("deleted RTO timer\n");
432 }
433
434 static inline void ccid2_new_ack(struct sock *sk,
435 struct ccid2_seq *seqp,
436 unsigned int *maxincr)
437 {
438 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
439
440 /* slow start */
441 if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
442 hctx->ccid2hctx_acks = 0;
443
444 /* We can increase cwnd at most maxincr [ack_ratio/2] */
445 if (*maxincr) {
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;
452 }
453 } else {
454 /* increased cwnd enough for this single ack */
455 hctx->ccid2hctx_ssacks = 0;
456 }
457 } else {
458 hctx->ccid2hctx_ssacks = 0;
459 hctx->ccid2hctx_acks++;
460
461 if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
462 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd + 1);
463 hctx->ccid2hctx_acks = 0;
464 }
465 }
466
467 /* update RTO */
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;
471 int s;
472
473 /* first measurement */
474 if (hctx->ccid2hctx_srtt == -1) {
475 ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
476 r, jiffies,
477 (unsigned long long)seqp->ccid2s_seq);
478 ccid2_change_srtt(hctx, r);
479 hctx->ccid2hctx_rttvar = r >> 1;
480 } else {
481 /* RTTVAR */
482 long tmp = hctx->ccid2hctx_srtt - r;
483 long srtt;
484
485 if (tmp < 0)
486 tmp *= -1;
487
488 tmp >>= 2;
489 hctx->ccid2hctx_rttvar *= 3;
490 hctx->ccid2hctx_rttvar >>= 2;
491 hctx->ccid2hctx_rttvar += tmp;
492
493 /* SRTT */
494 srtt = hctx->ccid2hctx_srtt;
495 srtt *= 7;
496 srtt >>= 3;
497 tmp = r >> 3;
498 srtt += tmp;
499 ccid2_change_srtt(hctx, srtt);
500 }
501 s = hctx->ccid2hctx_rttvar << 2;
502 /* clock granularity is 1 when based on jiffies */
503 if (!s)
504 s = 1;
505 hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
506
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] */
510 #if 1
511 if (s < 1)
512 hctx->ccid2hctx_rto = HZ;
513 #endif
514 /* max 60 seconds */
515 if (s > 60)
516 hctx->ccid2hctx_rto = HZ * 60;
517
518 hctx->ccid2hctx_lastrtt = jiffies;
519
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;
524 }
525
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);
529 }
530
531 static void ccid2_hc_tx_dec_pipe(struct sock *sk)
532 {
533 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
534
535 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe-1);
536 BUG_ON(hctx->ccid2hctx_pipe < 0);
537
538 if (hctx->ccid2hctx_pipe == 0)
539 ccid2_hc_tx_kill_rto_timer(sk);
540 }
541
542 static void ccid2_congestion_event(struct ccid2_hc_tx_sock *hctx,
543 struct ccid2_seq *seqp)
544 {
545 if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
546 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
547 return;
548 }
549
550 hctx->ccid2hctx_last_cong = jiffies;
551
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;
556 }
557
558 static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
559 {
560 struct dccp_sock *dp = dccp_sk(sk);
561 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
562 u64 ackno, seqno;
563 struct ccid2_seq *seqp;
564 unsigned char *vector;
565 unsigned char veclen;
566 int offset = 0;
567 int done = 0;
568 unsigned int maxincr = 0;
569
570 ccid2_hc_tx_check_sanity(hctx);
571 /* check reverse path congestion */
572 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
573
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
576 * -sorbo.
577 */
578 /* need to bootstrap */
579 if (hctx->ccid2hctx_rpdupack == -1) {
580 hctx->ccid2hctx_rpdupack = 0;
581 hctx->ccid2hctx_rpseq = seqno;
582 } else {
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++;
589
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;
595
596 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1);
597 }
598 }
599 }
600
601 /* check forward path congestion */
602 /* still didn't send out new data packets */
603 if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
604 return;
605
606 switch (DCCP_SKB_CB(skb)->dccpd_type) {
607 case DCCP_PKT_ACK:
608 case DCCP_PKT_DATAACK:
609 break;
610 default:
611 return;
612 }
613
614 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
615 if (after48(ackno, hctx->ccid2hctx_high_ack))
616 hctx->ccid2hctx_high_ack = ackno;
617
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;
623 break;
624 }
625 }
626
627 /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
628 * this single ack. I round up.
629 * -sorbo.
630 */
631 maxincr = dp->dccps_l_ack_ratio >> 1;
632 maxincr++;
633
634 /* go through all ack vectors */
635 while ((offset = ccid2_ackvector(sk, skb, offset,
636 &vector, &veclen)) != -1) {
637 /* go through this ack vector */
638 while (veclen--) {
639 const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
640 u64 ackno_end_rl;
641
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
648 * seqnos.
649 */
650 while (after48(seqp->ccid2s_seq, ackno)) {
651 if (seqp == hctx->ccid2hctx_seqt) {
652 done = 1;
653 break;
654 }
655 seqp = seqp->ccid2s_prev;
656 }
657 if (done)
658 break;
659
660 /* check all seqnos in the range of the vector
661 * run length
662 */
663 while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
664 const u8 state = *vector &
665 DCCP_ACKVEC_STATE_MASK;
666
667 /* new packet received or marked */
668 if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
669 !seqp->ccid2s_acked) {
670 if (state ==
671 DCCP_ACKVEC_STATE_ECN_MARKED) {
672 ccid2_congestion_event(hctx,
673 seqp);
674 } else
675 ccid2_new_ack(sk, seqp,
676 &maxincr);
677
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);
682 }
683 if (seqp == hctx->ccid2hctx_seqt) {
684 done = 1;
685 break;
686 }
687 seqp = seqp->ccid2s_next;
688 }
689 if (done)
690 break;
691
692
693 dccp_set_seqno(&ackno, ackno_end_rl - 1);
694 vector++;
695 }
696 if (done)
697 break;
698 }
699
700 /* The state about what is acked should be correct now
701 * Check for NUMDUPACK
702 */
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;
708 break;
709 }
710 }
711 done = 0;
712 while (1) {
713 if (seqp->ccid2s_acked) {
714 done++;
715 if (done == hctx->ccid2hctx_numdupack)
716 break;
717 }
718 if (seqp == hctx->ccid2hctx_seqt)
719 break;
720 seqp = seqp->ccid2s_prev;
721 }
722
723 /* If there are at least 3 acknowledgements, anything unacknowledged
724 * below the last sequence number is considered lost
725 */
726 if (done == hctx->ccid2hctx_numdupack) {
727 struct ccid2_seq *last_acked = seqp;
728
729 /* check for lost packets */
730 while (1) {
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
736 * one ack vector.
737 */
738 ccid2_congestion_event(hctx, seqp);
739 ccid2_hc_tx_dec_pipe(sk);
740 }
741 if (seqp == hctx->ccid2hctx_seqt)
742 break;
743 seqp = seqp->ccid2s_prev;
744 }
745
746 hctx->ccid2hctx_seqt = last_acked;
747 }
748
749 /* trim acked packets in tail */
750 while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
751 if (!hctx->ccid2hctx_seqt->ccid2s_acked)
752 break;
753
754 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
755 }
756
757 ccid2_hc_tx_check_sanity(hctx);
758 }
759
760 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
761 {
762 struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
763
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
767 * want.
768 */
769 hctx->ccid2hctx_ssthresh = ~0;
770 hctx->ccid2hctx_numdupack = 3;
771 hctx->ccid2hctx_seqbufc = 0;
772
773 /* XXX init ~ to window size... */
774 if (ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, GFP_ATOMIC) != 0)
775 return -ENOMEM;
776
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;
785
786 hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
787 hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
788 init_timer(&hctx->ccid2hctx_rtotimer);
789
790 ccid2_hc_tx_check_sanity(hctx);
791 return 0;
792 }
793
794 static void ccid2_hc_tx_exit(struct sock *sk)
795 {
796 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
797 int i;
798
799 ccid2_hc_tx_kill_rto_timer(sk);
800
801 for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
802 kfree(hctx->ccid2hctx_seqbuf[i]);
803 hctx->ccid2hctx_seqbufc = 0;
804 }
805
806 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
807 {
808 const struct dccp_sock *dp = dccp_sk(sk);
809 struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
810
811 switch (DCCP_SKB_CB(skb)->dccpd_type) {
812 case DCCP_PKT_DATA:
813 case DCCP_PKT_DATAACK:
814 hcrx->ccid2hcrx_data++;
815 if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
816 dccp_send_ack(sk);
817 hcrx->ccid2hcrx_data = 0;
818 }
819 break;
820 }
821 }
822
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,
835 };
836
837 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
838 module_param(ccid2_debug, int, 0444);
839 MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
840 #endif
841
842 static __init int ccid2_module_init(void)
843 {
844 return ccid_register(&ccid2);
845 }
846 module_init(ccid2_module_init);
847
848 static __exit void ccid2_module_exit(void)
849 {
850 ccid_unregister(&ccid2);
851 }
852 module_exit(ccid2_module_exit);
853
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");
Tomato firmware and modifications.