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Added !vmlinux.lds.h to .gitignore because it would otherwise be ignored.
[jz_linux_2.6.24.3.git] / net / dccp / ccids / ccid2.c
blobd694656b8800ec451156bf232f55e87a38f0aa00
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(dccp_delta_seqno(seqp->ccid2s_seq,
63 prev->ccid2s_seq ) >= 0);
64 BUG_ON(time_before(seqp->ccid2s_sent,
65 prev->ccid2s_sent));
66
67 seqp = prev;
68 }
69 }
70
71 BUG_ON(pipe != hctx->ccid2hctx_pipe);
72 ccid2_pr_debug("len of chain=%d\n", len);
73
74 do {
75 seqp = seqp->ccid2s_prev;
76 len++;
77 } while (seqp != hctx->ccid2hctx_seqh);
78
79 ccid2_pr_debug("total len=%d\n", len);
80 BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN);
81 }
82 #else
83 #define ccid2_pr_debug(format, a...)
84 #define ccid2_hc_tx_check_sanity(hctx)
85 #endif
86
87 static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx)
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(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any());
99 if (seqp == NULL)
100 return -ENOMEM;
101
102 for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) {
103 seqp[i].ccid2s_next = &seqp[i + 1];
104 seqp[i + 1].ccid2s_prev = &seqp[i];
105 }
106 seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp;
107 seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 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[CCID2_SEQBUF_LEN - 1];
118 seqp[CCID2_SEQBUF_LEN - 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 = ccid2_hc_tx_sk(sk);
131
132 ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe,
133 hctx->ccid2hctx_cwnd);
134
135 if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) {
136 /* OK we can send... make sure previous packet was sent off */
137 if (!hctx->ccid2hctx_sendwait) {
138 hctx->ccid2hctx_sendwait = 1;
139 return 0;
140 }
141 }
142
143 return 1; /* XXX CCID should dequeue when ready instead of polling */
144 }
145
146 static void ccid2_change_l_ack_ratio(struct sock *sk, int val)
147 {
148 struct dccp_sock *dp = dccp_sk(sk);
149 /*
150 * XXX I don't really agree with val != 2. If cwnd is 1, ack ratio
151 * should be 1... it shouldn't be allowed to become 2.
152 * -sorbo.
153 */
154 if (val != 2) {
155 const struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
156 int max = hctx->ccid2hctx_cwnd / 2;
157
158 /* round up */
159 if (hctx->ccid2hctx_cwnd & 1)
160 max++;
161
162 if (val > max)
163 val = max;
164 }
165
166 ccid2_pr_debug("changing local ack ratio to %d\n", val);
167 WARN_ON(val <= 0);
168 dp->dccps_l_ack_ratio = val;
169 }
170
171 static void ccid2_change_cwnd(struct ccid2_hc_tx_sock *hctx, u32 val)
172 {
173 /* XXX do we need to change ack ratio? */
174 hctx->ccid2hctx_cwnd = val? : 1;
175 ccid2_pr_debug("changed cwnd to %u\n", hctx->ccid2hctx_cwnd);
176 }
177
178 static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val)
179 {
180 ccid2_pr_debug("change SRTT to %ld\n", val);
181 hctx->ccid2hctx_srtt = val;
182 }
183
184 static void ccid2_change_pipe(struct ccid2_hc_tx_sock *hctx, long val)
185 {
186 hctx->ccid2hctx_pipe = val;
187 }
188
189 static void ccid2_start_rto_timer(struct sock *sk);
190
191 static void ccid2_hc_tx_rto_expire(unsigned long data)
192 {
193 struct sock *sk = (struct sock *)data;
194 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
195 long s;
196
197 bh_lock_sock(sk);
198 if (sock_owned_by_user(sk)) {
199 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
200 jiffies + HZ / 5);
201 goto out;
202 }
203
204 ccid2_pr_debug("RTO_EXPIRE\n");
205
206 ccid2_hc_tx_check_sanity(hctx);
207
208 /* back-off timer */
209 hctx->ccid2hctx_rto <<= 1;
210
211 s = hctx->ccid2hctx_rto / HZ;
212 if (s > 60)
213 hctx->ccid2hctx_rto = 60 * HZ;
214
215 ccid2_start_rto_timer(sk);
216
217 /* adjust pipe, cwnd etc */
218 ccid2_change_pipe(hctx, 0);
219 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1;
220 if (hctx->ccid2hctx_ssthresh < 2)
221 hctx->ccid2hctx_ssthresh = 2;
222 ccid2_change_cwnd(hctx, 1);
223
224 /* clear state about stuff we sent */
225 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
226 hctx->ccid2hctx_ssacks = 0;
227 hctx->ccid2hctx_acks = 0;
228 hctx->ccid2hctx_sent = 0;
229
230 /* clear ack ratio state. */
231 hctx->ccid2hctx_arsent = 0;
232 hctx->ccid2hctx_ackloss = 0;
233 hctx->ccid2hctx_rpseq = 0;
234 hctx->ccid2hctx_rpdupack = -1;
235 ccid2_change_l_ack_ratio(sk, 1);
236 ccid2_hc_tx_check_sanity(hctx);
237 out:
238 bh_unlock_sock(sk);
239 sock_put(sk);
240 }
241
242 static void ccid2_start_rto_timer(struct sock *sk)
243 {
244 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
245
246 ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
247
248 BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
249 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
250 jiffies + hctx->ccid2hctx_rto);
251 }
252
253 static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
254 {
255 struct dccp_sock *dp = dccp_sk(sk);
256 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
257 struct ccid2_seq *next;
258 u64 seq;
259
260 ccid2_hc_tx_check_sanity(hctx);
261
262 BUG_ON(!hctx->ccid2hctx_sendwait);
263 hctx->ccid2hctx_sendwait = 0;
264 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe + 1);
265 BUG_ON(hctx->ccid2hctx_pipe < 0);
266
267 /* There is an issue. What if another packet is sent between
268 * packet_send() and packet_sent(). Then the sequence number would be
269 * wrong.
270 * -sorbo.
271 */
272 seq = dp->dccps_gss;
273
274 hctx->ccid2hctx_seqh->ccid2s_seq = seq;
275 hctx->ccid2hctx_seqh->ccid2s_acked = 0;
276 hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
277
278 next = hctx->ccid2hctx_seqh->ccid2s_next;
279 /* check if we need to alloc more space */
280 if (next == hctx->ccid2hctx_seqt) {
281 if (ccid2_hc_tx_alloc_seq(hctx)) {
282 DCCP_CRIT("packet history - out of memory!");
283 /* FIXME: find a more graceful way to bail out */
284 return;
285 }
286 next = hctx->ccid2hctx_seqh->ccid2s_next;
287 BUG_ON(next == hctx->ccid2hctx_seqt);
288 }
289 hctx->ccid2hctx_seqh = next;
290
291 ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
292 hctx->ccid2hctx_pipe);
293
294 hctx->ccid2hctx_sent++;
295
296 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
297 hctx->ccid2hctx_arsent++;
298 /* We had an ack loss in this window... */
299 if (hctx->ccid2hctx_ackloss) {
300 if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
301 hctx->ccid2hctx_arsent = 0;
302 hctx->ccid2hctx_ackloss = 0;
303 }
304 } else {
305 /* No acks lost up to now... */
306 /* decrease ack ratio if enough packets were sent */
307 if (dp->dccps_l_ack_ratio > 1) {
308 /* XXX don't calculate denominator each time */
309 int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
310 dp->dccps_l_ack_ratio;
311
312 denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
313
314 if (hctx->ccid2hctx_arsent >= denom) {
315 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
316 hctx->ccid2hctx_arsent = 0;
317 }
318 } else {
319 /* we can't increase ack ratio further [1] */
320 hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
321 }
322 }
323
324 /* setup RTO timer */
325 if (!timer_pending(&hctx->ccid2hctx_rtotimer))
326 ccid2_start_rto_timer(sk);
327
328 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
329 ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe);
330 ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)seq);
331 do {
332 struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
333
334 while (seqp != hctx->ccid2hctx_seqh) {
335 ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
336 (unsigned long long)seqp->ccid2s_seq,
337 seqp->ccid2s_acked, seqp->ccid2s_sent);
338 seqp = seqp->ccid2s_next;
339 }
340 } while (0);
341 ccid2_pr_debug("=========\n");
342 ccid2_hc_tx_check_sanity(hctx);
343 #endif
344 }
345
346 /* XXX Lame code duplication!
347 * returns -1 if none was found.
348 * else returns the next offset to use in the function call.
349 */
350 static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
351 unsigned char **vec, unsigned char *veclen)
352 {
353 const struct dccp_hdr *dh = dccp_hdr(skb);
354 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
355 unsigned char *opt_ptr;
356 const unsigned char *opt_end = (unsigned char *)dh +
357 (dh->dccph_doff * 4);
358 unsigned char opt, len;
359 unsigned char *value;
360
361 BUG_ON(offset < 0);
362 options += offset;
363 opt_ptr = options;
364 if (opt_ptr >= opt_end)
365 return -1;
366
367 while (opt_ptr != opt_end) {
368 opt = *opt_ptr++;
369 len = 0;
370 value = NULL;
371
372 /* Check if this isn't a single byte option */
373 if (opt > DCCPO_MAX_RESERVED) {
374 if (opt_ptr == opt_end)
375 goto out_invalid_option;
376
377 len = *opt_ptr++;
378 if (len < 3)
379 goto out_invalid_option;
380 /*
381 * Remove the type and len fields, leaving
382 * just the value size
383 */
384 len -= 2;
385 value = opt_ptr;
386 opt_ptr += len;
387
388 if (opt_ptr > opt_end)
389 goto out_invalid_option;
390 }
391
392 switch (opt) {
393 case DCCPO_ACK_VECTOR_0:
394 case DCCPO_ACK_VECTOR_1:
395 *vec = value;
396 *veclen = len;
397 return offset + (opt_ptr - options);
398 }
399 }
400
401 return -1;
402
403 out_invalid_option:
404 DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
405 return -1;
406 }
407
408 static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
409 {
410 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
411
412 sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
413 ccid2_pr_debug("deleted RTO timer\n");
414 }
415
416 static inline void ccid2_new_ack(struct sock *sk,
417 struct ccid2_seq *seqp,
418 unsigned int *maxincr)
419 {
420 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
421
422 /* slow start */
423 if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
424 hctx->ccid2hctx_acks = 0;
425
426 /* We can increase cwnd at most maxincr [ack_ratio/2] */
427 if (*maxincr) {
428 /* increase every 2 acks */
429 hctx->ccid2hctx_ssacks++;
430 if (hctx->ccid2hctx_ssacks == 2) {
431 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd+1);
432 hctx->ccid2hctx_ssacks = 0;
433 *maxincr = *maxincr - 1;
434 }
435 } else {
436 /* increased cwnd enough for this single ack */
437 hctx->ccid2hctx_ssacks = 0;
438 }
439 } else {
440 hctx->ccid2hctx_ssacks = 0;
441 hctx->ccid2hctx_acks++;
442
443 if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
444 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd + 1);
445 hctx->ccid2hctx_acks = 0;
446 }
447 }
448
449 /* update RTO */
450 if (hctx->ccid2hctx_srtt == -1 ||
451 time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) {
452 unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
453 int s;
454
455 /* first measurement */
456 if (hctx->ccid2hctx_srtt == -1) {
457 ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
458 r, jiffies,
459 (unsigned long long)seqp->ccid2s_seq);
460 ccid2_change_srtt(hctx, r);
461 hctx->ccid2hctx_rttvar = r >> 1;
462 } else {
463 /* RTTVAR */
464 long tmp = hctx->ccid2hctx_srtt - r;
465 long srtt;
466
467 if (tmp < 0)
468 tmp *= -1;
469
470 tmp >>= 2;
471 hctx->ccid2hctx_rttvar *= 3;
472 hctx->ccid2hctx_rttvar >>= 2;
473 hctx->ccid2hctx_rttvar += tmp;
474
475 /* SRTT */
476 srtt = hctx->ccid2hctx_srtt;
477 srtt *= 7;
478 srtt >>= 3;
479 tmp = r >> 3;
480 srtt += tmp;
481 ccid2_change_srtt(hctx, srtt);
482 }
483 s = hctx->ccid2hctx_rttvar << 2;
484 /* clock granularity is 1 when based on jiffies */
485 if (!s)
486 s = 1;
487 hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
488
489 /* must be at least a second */
490 s = hctx->ccid2hctx_rto / HZ;
491 /* DCCP doesn't require this [but I like it cuz my code sux] */
492 #if 1
493 if (s < 1)
494 hctx->ccid2hctx_rto = HZ;
495 #endif
496 /* max 60 seconds */
497 if (s > 60)
498 hctx->ccid2hctx_rto = HZ * 60;
499
500 hctx->ccid2hctx_lastrtt = jiffies;
501
502 ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
503 hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
504 hctx->ccid2hctx_rto, HZ, r);
505 hctx->ccid2hctx_sent = 0;
506 }
507
508 /* we got a new ack, so re-start RTO timer */
509 ccid2_hc_tx_kill_rto_timer(sk);
510 ccid2_start_rto_timer(sk);
511 }
512
513 static void ccid2_hc_tx_dec_pipe(struct sock *sk)
514 {
515 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
516
517 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe-1);
518 BUG_ON(hctx->ccid2hctx_pipe < 0);
519
520 if (hctx->ccid2hctx_pipe == 0)
521 ccid2_hc_tx_kill_rto_timer(sk);
522 }
523
524 static void ccid2_congestion_event(struct ccid2_hc_tx_sock *hctx,
525 struct ccid2_seq *seqp)
526 {
527 if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
528 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
529 return;
530 }
531
532 hctx->ccid2hctx_last_cong = jiffies;
533
534 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd >> 1);
535 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd;
536 if (hctx->ccid2hctx_ssthresh < 2)
537 hctx->ccid2hctx_ssthresh = 2;
538 }
539
540 static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
541 {
542 struct dccp_sock *dp = dccp_sk(sk);
543 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
544 u64 ackno, seqno;
545 struct ccid2_seq *seqp;
546 unsigned char *vector;
547 unsigned char veclen;
548 int offset = 0;
549 int done = 0;
550 unsigned int maxincr = 0;
551
552 ccid2_hc_tx_check_sanity(hctx);
553 /* check reverse path congestion */
554 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
555
556 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
557 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
558 * -sorbo.
559 */
560 /* need to bootstrap */
561 if (hctx->ccid2hctx_rpdupack == -1) {
562 hctx->ccid2hctx_rpdupack = 0;
563 hctx->ccid2hctx_rpseq = seqno;
564 } else {
565 /* check if packet is consecutive */
566 if (dccp_delta_seqno(hctx->ccid2hctx_rpseq, seqno) == 1)
567 hctx->ccid2hctx_rpseq = seqno;
568 /* it's a later packet */
569 else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
570 hctx->ccid2hctx_rpdupack++;
571
572 /* check if we got enough dupacks */
573 if (hctx->ccid2hctx_rpdupack >=
574 hctx->ccid2hctx_numdupack) {
575 hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
576 hctx->ccid2hctx_rpseq = 0;
577
578 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1);
579 }
580 }
581 }
582
583 /* check forward path congestion */
584 /* still didn't send out new data packets */
585 if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
586 return;
587
588 switch (DCCP_SKB_CB(skb)->dccpd_type) {
589 case DCCP_PKT_ACK:
590 case DCCP_PKT_DATAACK:
591 break;
592 default:
593 return;
594 }
595
596 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
597 if (after48(ackno, hctx->ccid2hctx_high_ack))
598 hctx->ccid2hctx_high_ack = ackno;
599
600 seqp = hctx->ccid2hctx_seqt;
601 while (before48(seqp->ccid2s_seq, ackno)) {
602 seqp = seqp->ccid2s_next;
603 if (seqp == hctx->ccid2hctx_seqh) {
604 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
605 break;
606 }
607 }
608
609 /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
610 * this single ack. I round up.
611 * -sorbo.
612 */
613 maxincr = dp->dccps_l_ack_ratio >> 1;
614 maxincr++;
615
616 /* go through all ack vectors */
617 while ((offset = ccid2_ackvector(sk, skb, offset,
618 &vector, &veclen)) != -1) {
619 /* go through this ack vector */
620 while (veclen--) {
621 const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
622 u64 ackno_end_rl;
623
624 dccp_set_seqno(&ackno_end_rl, ackno - rl);
625 ccid2_pr_debug("ackvec start:%llu end:%llu\n",
626 (unsigned long long)ackno,
627 (unsigned long long)ackno_end_rl);
628 /* if the seqno we are analyzing is larger than the
629 * current ackno, then move towards the tail of our
630 * seqnos.
631 */
632 while (after48(seqp->ccid2s_seq, ackno)) {
633 if (seqp == hctx->ccid2hctx_seqt) {
634 done = 1;
635 break;
636 }
637 seqp = seqp->ccid2s_prev;
638 }
639 if (done)
640 break;
641
642 /* check all seqnos in the range of the vector
643 * run length
644 */
645 while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
646 const u8 state = *vector &
647 DCCP_ACKVEC_STATE_MASK;
648
649 /* new packet received or marked */
650 if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
651 !seqp->ccid2s_acked) {
652 if (state ==
653 DCCP_ACKVEC_STATE_ECN_MARKED) {
654 ccid2_congestion_event(hctx,
655 seqp);
656 } else
657 ccid2_new_ack(sk, seqp,
658 &maxincr);
659
660 seqp->ccid2s_acked = 1;
661 ccid2_pr_debug("Got ack for %llu\n",
662 (unsigned long long)seqp->ccid2s_seq);
663 ccid2_hc_tx_dec_pipe(sk);
664 }
665 if (seqp == hctx->ccid2hctx_seqt) {
666 done = 1;
667 break;
668 }
669 seqp = seqp->ccid2s_next;
670 }
671 if (done)
672 break;
673
674
675 dccp_set_seqno(&ackno, ackno_end_rl - 1);
676 vector++;
677 }
678 if (done)
679 break;
680 }
681
682 /* The state about what is acked should be correct now
683 * Check for NUMDUPACK
684 */
685 seqp = hctx->ccid2hctx_seqt;
686 while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) {
687 seqp = seqp->ccid2s_next;
688 if (seqp == hctx->ccid2hctx_seqh) {
689 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
690 break;
691 }
692 }
693 done = 0;
694 while (1) {
695 if (seqp->ccid2s_acked) {
696 done++;
697 if (done == hctx->ccid2hctx_numdupack)
698 break;
699 }
700 if (seqp == hctx->ccid2hctx_seqt)
701 break;
702 seqp = seqp->ccid2s_prev;
703 }
704
705 /* If there are at least 3 acknowledgements, anything unacknowledged
706 * below the last sequence number is considered lost
707 */
708 if (done == hctx->ccid2hctx_numdupack) {
709 struct ccid2_seq *last_acked = seqp;
710
711 /* check for lost packets */
712 while (1) {
713 if (!seqp->ccid2s_acked) {
714 ccid2_pr_debug("Packet lost: %llu\n",
715 (unsigned long long)seqp->ccid2s_seq);
716 /* XXX need to traverse from tail -> head in
717 * order to detect multiple congestion events in
718 * one ack vector.
719 */
720 ccid2_congestion_event(hctx, seqp);
721 ccid2_hc_tx_dec_pipe(sk);
722 }
723 if (seqp == hctx->ccid2hctx_seqt)
724 break;
725 seqp = seqp->ccid2s_prev;
726 }
727
728 hctx->ccid2hctx_seqt = last_acked;
729 }
730
731 /* trim acked packets in tail */
732 while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
733 if (!hctx->ccid2hctx_seqt->ccid2s_acked)
734 break;
735
736 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
737 }
738
739 ccid2_hc_tx_check_sanity(hctx);
740 }
741
742 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
743 {
744 struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
745
746 ccid2_change_cwnd(hctx, 1);
747 /* Initialize ssthresh to infinity. This means that we will exit the
748 * initial slow-start after the first packet loss. This is what we
749 * want.
750 */
751 hctx->ccid2hctx_ssthresh = ~0;
752 hctx->ccid2hctx_numdupack = 3;
753
754 /* XXX init ~ to window size... */
755 if (ccid2_hc_tx_alloc_seq(hctx))
756 return -ENOMEM;
757
758 hctx->ccid2hctx_rto = 3 * HZ;
759 ccid2_change_srtt(hctx, -1);
760 hctx->ccid2hctx_rttvar = -1;
761 hctx->ccid2hctx_rpdupack = -1;
762 hctx->ccid2hctx_last_cong = jiffies;
763
764 hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
765 hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
766 init_timer(&hctx->ccid2hctx_rtotimer);
767
768 ccid2_hc_tx_check_sanity(hctx);
769 return 0;
770 }
771
772 static void ccid2_hc_tx_exit(struct sock *sk)
773 {
774 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
775 int i;
776
777 ccid2_hc_tx_kill_rto_timer(sk);
778
779 for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
780 kfree(hctx->ccid2hctx_seqbuf[i]);
781 hctx->ccid2hctx_seqbufc = 0;
782 }
783
784 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
785 {
786 const struct dccp_sock *dp = dccp_sk(sk);
787 struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
788
789 switch (DCCP_SKB_CB(skb)->dccpd_type) {
790 case DCCP_PKT_DATA:
791 case DCCP_PKT_DATAACK:
792 hcrx->ccid2hcrx_data++;
793 if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
794 dccp_send_ack(sk);
795 hcrx->ccid2hcrx_data = 0;
796 }
797 break;
798 }
799 }
800
801 static struct ccid_operations ccid2 = {
802 .ccid_id = DCCPC_CCID2,
803 .ccid_name = "ccid2",
804 .ccid_owner = THIS_MODULE,
805 .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
806 .ccid_hc_tx_init = ccid2_hc_tx_init,
807 .ccid_hc_tx_exit = ccid2_hc_tx_exit,
808 .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
809 .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
810 .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
811 .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
812 .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
813 };
814
815 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
816 module_param(ccid2_debug, bool, 0444);
817 MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
818 #endif
819
820 static __init int ccid2_module_init(void)
821 {
822 return ccid_register(&ccid2);
823 }
824 module_init(ccid2_module_init);
825
826 static __exit void ccid2_module_exit(void)
827 {
828 ccid_unregister(&ccid2);
829 }
830 module_exit(ccid2_module_exit);
831
832 MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
833 MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID");
834 MODULE_LICENSE("GPL");
835 MODULE_ALIAS("net-dccp-ccid-2");
linux 2.6.24.3 for JZ soc