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[CCID2]: Remove redundant case block
[deliverable/linux.git] / net / dccp / ccids / ccid2.c
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)
87 {
88 struct ccid2_seq *seqp;
89 int i;
90
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*)))
94 return -ENOMEM;
95
96 /* allocate buffer and initialize linked list */
97 seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any());
98 if (seqp == NULL)
99 return -ENOMEM;
100
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];
104 }
105 seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp;
106 seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
107
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;
111 else {
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;
115
116 hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
117 seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->ccid2hctx_seqt;
118 }
119
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++;
123
124 return 0;
125 }
126
127 static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
128 {
129 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
130
131 ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe,
132 hctx->ccid2hctx_cwnd);
133
134 if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) {
135 /* OK we can send... make sure previous packet was sent off */
136 if (!hctx->ccid2hctx_sendwait) {
137 hctx->ccid2hctx_sendwait = 1;
138 return 0;
139 }
140 }
141
142 return 1; /* XXX CCID should dequeue when ready instead of polling */
143 }
144
145 static void ccid2_change_l_ack_ratio(struct sock *sk, int val)
146 {
147 struct dccp_sock *dp = dccp_sk(sk);
148 /*
149 * XXX I don't really agree with val != 2. If cwnd is 1, ack ratio
150 * should be 1... it shouldn't be allowed to become 2.
151 * -sorbo.
152 */
153 if (val != 2) {
154 const struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
155 int max = hctx->ccid2hctx_cwnd / 2;
156
157 /* round up */
158 if (hctx->ccid2hctx_cwnd & 1)
159 max++;
160
161 if (val > max)
162 val = max;
163 }
164
165 ccid2_pr_debug("changing local ack ratio to %d\n", val);
166 WARN_ON(val <= 0);
167 dp->dccps_l_ack_ratio = val;
168 }
169
170 static void ccid2_change_cwnd(struct ccid2_hc_tx_sock *hctx, u32 val)
171 {
172 /* XXX do we need to change ack ratio? */
173 hctx->ccid2hctx_cwnd = val? : 1;
174 ccid2_pr_debug("changed cwnd to %u\n", hctx->ccid2hctx_cwnd);
175 }
176
177 static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val)
178 {
179 ccid2_pr_debug("change SRTT to %ld\n", val);
180 hctx->ccid2hctx_srtt = val;
181 }
182
183 static void ccid2_change_pipe(struct ccid2_hc_tx_sock *hctx, long val)
184 {
185 hctx->ccid2hctx_pipe = val;
186 }
187
188 static void ccid2_start_rto_timer(struct sock *sk);
189
190 static void ccid2_hc_tx_rto_expire(unsigned long data)
191 {
192 struct sock *sk = (struct sock *)data;
193 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
194 long s;
195
196 bh_lock_sock(sk);
197 if (sock_owned_by_user(sk)) {
198 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
199 jiffies + HZ / 5);
200 goto out;
201 }
202
203 ccid2_pr_debug("RTO_EXPIRE\n");
204
205 ccid2_hc_tx_check_sanity(hctx);
206
207 /* back-off timer */
208 hctx->ccid2hctx_rto <<= 1;
209
210 s = hctx->ccid2hctx_rto / HZ;
211 if (s > 60)
212 hctx->ccid2hctx_rto = 60 * HZ;
213
214 ccid2_start_rto_timer(sk);
215
216 /* adjust pipe, cwnd etc */
217 ccid2_change_pipe(hctx, 0);
218 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1;
219 if (hctx->ccid2hctx_ssthresh < 2)
220 hctx->ccid2hctx_ssthresh = 2;
221 ccid2_change_cwnd(hctx, 1);
222
223 /* clear state about stuff we sent */
224 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
225 hctx->ccid2hctx_ssacks = 0;
226 hctx->ccid2hctx_acks = 0;
227 hctx->ccid2hctx_sent = 0;
228
229 /* clear ack ratio state. */
230 hctx->ccid2hctx_arsent = 0;
231 hctx->ccid2hctx_ackloss = 0;
232 hctx->ccid2hctx_rpseq = 0;
233 hctx->ccid2hctx_rpdupack = -1;
234 ccid2_change_l_ack_ratio(sk, 1);
235 ccid2_hc_tx_check_sanity(hctx);
236 out:
237 bh_unlock_sock(sk);
238 sock_put(sk);
239 }
240
241 static void ccid2_start_rto_timer(struct sock *sk)
242 {
243 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
244
245 ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
246
247 BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
248 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
249 jiffies + hctx->ccid2hctx_rto);
250 }
251
252 static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
253 {
254 struct dccp_sock *dp = dccp_sk(sk);
255 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
256 struct ccid2_seq *next;
257 u64 seq;
258
259 ccid2_hc_tx_check_sanity(hctx);
260
261 BUG_ON(!hctx->ccid2hctx_sendwait);
262 hctx->ccid2hctx_sendwait = 0;
263 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe + 1);
264 BUG_ON(hctx->ccid2hctx_pipe < 0);
265
266 /* There is an issue. What if another packet is sent between
267 * packet_send() and packet_sent(). Then the sequence number would be
268 * wrong.
269 * -sorbo.
270 */
271 seq = dp->dccps_gss;
272
273 hctx->ccid2hctx_seqh->ccid2s_seq = seq;
274 hctx->ccid2hctx_seqh->ccid2s_acked = 0;
275 hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
276
277 next = hctx->ccid2hctx_seqh->ccid2s_next;
278 /* check if we need to alloc more space */
279 if (next == hctx->ccid2hctx_seqt) {
280 if (ccid2_hc_tx_alloc_seq(hctx)) {
281 DCCP_CRIT("packet history - out of memory!");
282 /* FIXME: find a more graceful way to bail out */
283 return;
284 }
285 next = hctx->ccid2hctx_seqh->ccid2s_next;
286 BUG_ON(next == hctx->ccid2hctx_seqt);
287 }
288 hctx->ccid2hctx_seqh = next;
289
290 ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
291 hctx->ccid2hctx_pipe);
292
293 hctx->ccid2hctx_sent++;
294
295 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
296 hctx->ccid2hctx_arsent++;
297 /* We had an ack loss in this window... */
298 if (hctx->ccid2hctx_ackloss) {
299 if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
300 hctx->ccid2hctx_arsent = 0;
301 hctx->ccid2hctx_ackloss = 0;
302 }
303 } else {
304 /* No acks lost up to now... */
305 /* decrease ack ratio if enough packets were sent */
306 if (dp->dccps_l_ack_ratio > 1) {
307 /* XXX don't calculate denominator each time */
308 int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
309 dp->dccps_l_ack_ratio;
310
311 denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
312
313 if (hctx->ccid2hctx_arsent >= denom) {
314 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
315 hctx->ccid2hctx_arsent = 0;
316 }
317 } else {
318 /* we can't increase ack ratio further [1] */
319 hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
320 }
321 }
322
323 /* setup RTO timer */
324 if (!timer_pending(&hctx->ccid2hctx_rtotimer))
325 ccid2_start_rto_timer(sk);
326
327 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
328 ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe);
329 ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)seq);
330 do {
331 struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
332
333 while (seqp != hctx->ccid2hctx_seqh) {
334 ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
335 (unsigned long long)seqp->ccid2s_seq,
336 seqp->ccid2s_acked, seqp->ccid2s_sent);
337 seqp = seqp->ccid2s_next;
338 }
339 } while (0);
340 ccid2_pr_debug("=========\n");
341 ccid2_hc_tx_check_sanity(hctx);
342 #endif
343 }
344
345 /* XXX Lame code duplication!
346 * returns -1 if none was found.
347 * else returns the next offset to use in the function call.
348 */
349 static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
350 unsigned char **vec, unsigned char *veclen)
351 {
352 const struct dccp_hdr *dh = dccp_hdr(skb);
353 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
354 unsigned char *opt_ptr;
355 const unsigned char *opt_end = (unsigned char *)dh +
356 (dh->dccph_doff * 4);
357 unsigned char opt, len;
358 unsigned char *value;
359
360 BUG_ON(offset < 0);
361 options += offset;
362 opt_ptr = options;
363 if (opt_ptr >= opt_end)
364 return -1;
365
366 while (opt_ptr != opt_end) {
367 opt = *opt_ptr++;
368 len = 0;
369 value = NULL;
370
371 /* Check if this isn't a single byte option */
372 if (opt > DCCPO_MAX_RESERVED) {
373 if (opt_ptr == opt_end)
374 goto out_invalid_option;
375
376 len = *opt_ptr++;
377 if (len < 3)
378 goto out_invalid_option;
379 /*
380 * Remove the type and len fields, leaving
381 * just the value size
382 */
383 len -= 2;
384 value = opt_ptr;
385 opt_ptr += len;
386
387 if (opt_ptr > opt_end)
388 goto out_invalid_option;
389 }
390
391 switch (opt) {
392 case DCCPO_ACK_VECTOR_0:
393 case DCCPO_ACK_VECTOR_1:
394 *vec = value;
395 *veclen = len;
396 return offset + (opt_ptr - options);
397 }
398 }
399
400 return -1;
401
402 out_invalid_option:
403 DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
404 return -1;
405 }
406
407 static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
408 {
409 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
410
411 sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
412 ccid2_pr_debug("deleted RTO timer\n");
413 }
414
415 static inline void ccid2_new_ack(struct sock *sk,
416 struct ccid2_seq *seqp,
417 unsigned int *maxincr)
418 {
419 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
420
421 /* slow start */
422 if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
423 hctx->ccid2hctx_acks = 0;
424
425 /* We can increase cwnd at most maxincr [ack_ratio/2] */
426 if (*maxincr) {
427 /* increase every 2 acks */
428 hctx->ccid2hctx_ssacks++;
429 if (hctx->ccid2hctx_ssacks == 2) {
430 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd+1);
431 hctx->ccid2hctx_ssacks = 0;
432 *maxincr = *maxincr - 1;
433 }
434 } else {
435 /* increased cwnd enough for this single ack */
436 hctx->ccid2hctx_ssacks = 0;
437 }
438 } else {
439 hctx->ccid2hctx_ssacks = 0;
440 hctx->ccid2hctx_acks++;
441
442 if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
443 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd + 1);
444 hctx->ccid2hctx_acks = 0;
445 }
446 }
447
448 /* update RTO */
449 if (hctx->ccid2hctx_srtt == -1 ||
450 time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) {
451 unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
452 int s;
453
454 /* first measurement */
455 if (hctx->ccid2hctx_srtt == -1) {
456 ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
457 r, jiffies,
458 (unsigned long long)seqp->ccid2s_seq);
459 ccid2_change_srtt(hctx, r);
460 hctx->ccid2hctx_rttvar = r >> 1;
461 } else {
462 /* RTTVAR */
463 long tmp = hctx->ccid2hctx_srtt - r;
464 long srtt;
465
466 if (tmp < 0)
467 tmp *= -1;
468
469 tmp >>= 2;
470 hctx->ccid2hctx_rttvar *= 3;
471 hctx->ccid2hctx_rttvar >>= 2;
472 hctx->ccid2hctx_rttvar += tmp;
473
474 /* SRTT */
475 srtt = hctx->ccid2hctx_srtt;
476 srtt *= 7;
477 srtt >>= 3;
478 tmp = r >> 3;
479 srtt += tmp;
480 ccid2_change_srtt(hctx, srtt);
481 }
482 s = hctx->ccid2hctx_rttvar << 2;
483 /* clock granularity is 1 when based on jiffies */
484 if (!s)
485 s = 1;
486 hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
487
488 /* must be at least a second */
489 s = hctx->ccid2hctx_rto / HZ;
490 /* DCCP doesn't require this [but I like it cuz my code sux] */
491 #if 1
492 if (s < 1)
493 hctx->ccid2hctx_rto = HZ;
494 #endif
495 /* max 60 seconds */
496 if (s > 60)
497 hctx->ccid2hctx_rto = HZ * 60;
498
499 hctx->ccid2hctx_lastrtt = jiffies;
500
501 ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
502 hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
503 hctx->ccid2hctx_rto, HZ, r);
504 hctx->ccid2hctx_sent = 0;
505 }
506
507 /* we got a new ack, so re-start RTO timer */
508 ccid2_hc_tx_kill_rto_timer(sk);
509 ccid2_start_rto_timer(sk);
510 }
511
512 static void ccid2_hc_tx_dec_pipe(struct sock *sk)
513 {
514 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
515
516 ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe-1);
517 BUG_ON(hctx->ccid2hctx_pipe < 0);
518
519 if (hctx->ccid2hctx_pipe == 0)
520 ccid2_hc_tx_kill_rto_timer(sk);
521 }
522
523 static void ccid2_congestion_event(struct ccid2_hc_tx_sock *hctx,
524 struct ccid2_seq *seqp)
525 {
526 if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
527 ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
528 return;
529 }
530
531 hctx->ccid2hctx_last_cong = jiffies;
532
533 ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd >> 1);
534 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd;
535 if (hctx->ccid2hctx_ssthresh < 2)
536 hctx->ccid2hctx_ssthresh = 2;
537 }
538
539 static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
540 {
541 struct dccp_sock *dp = dccp_sk(sk);
542 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
543 u64 ackno, seqno;
544 struct ccid2_seq *seqp;
545 unsigned char *vector;
546 unsigned char veclen;
547 int offset = 0;
548 int done = 0;
549 unsigned int maxincr = 0;
550
551 ccid2_hc_tx_check_sanity(hctx);
552 /* check reverse path congestion */
553 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
554
555 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
556 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
557 * -sorbo.
558 */
559 /* need to bootstrap */
560 if (hctx->ccid2hctx_rpdupack == -1) {
561 hctx->ccid2hctx_rpdupack = 0;
562 hctx->ccid2hctx_rpseq = seqno;
563 } else {
564 /* check if packet is consecutive */
565 if ((hctx->ccid2hctx_rpseq + 1) == seqno)
566 hctx->ccid2hctx_rpseq++;
567 /* it's a later packet */
568 else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
569 hctx->ccid2hctx_rpdupack++;
570
571 /* check if we got enough dupacks */
572 if (hctx->ccid2hctx_rpdupack >=
573 hctx->ccid2hctx_numdupack) {
574 hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
575 hctx->ccid2hctx_rpseq = 0;
576
577 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1);
578 }
579 }
580 }
581
582 /* check forward path congestion */
583 /* still didn't send out new data packets */
584 if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
585 return;
586
587 switch (DCCP_SKB_CB(skb)->dccpd_type) {
588 case DCCP_PKT_ACK:
589 case DCCP_PKT_DATAACK:
590 break;
591 default:
592 return;
593 }
594
595 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
596 if (after48(ackno, hctx->ccid2hctx_high_ack))
597 hctx->ccid2hctx_high_ack = ackno;
598
599 seqp = hctx->ccid2hctx_seqt;
600 while (before48(seqp->ccid2s_seq, ackno)) {
601 seqp = seqp->ccid2s_next;
602 if (seqp == hctx->ccid2hctx_seqh) {
603 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
604 break;
605 }
606 }
607
608 /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
609 * this single ack. I round up.
610 * -sorbo.
611 */
612 maxincr = dp->dccps_l_ack_ratio >> 1;
613 maxincr++;
614
615 /* go through all ack vectors */
616 while ((offset = ccid2_ackvector(sk, skb, offset,
617 &vector, &veclen)) != -1) {
618 /* go through this ack vector */
619 while (veclen--) {
620 const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
621 u64 ackno_end_rl;
622
623 dccp_set_seqno(&ackno_end_rl, ackno - rl);
624 ccid2_pr_debug("ackvec start:%llu end:%llu\n",
625 (unsigned long long)ackno,
626 (unsigned long long)ackno_end_rl);
627 /* if the seqno we are analyzing is larger than the
628 * current ackno, then move towards the tail of our
629 * seqnos.
630 */
631 while (after48(seqp->ccid2s_seq, ackno)) {
632 if (seqp == hctx->ccid2hctx_seqt) {
633 done = 1;
634 break;
635 }
636 seqp = seqp->ccid2s_prev;
637 }
638 if (done)
639 break;
640
641 /* check all seqnos in the range of the vector
642 * run length
643 */
644 while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
645 const u8 state = *vector &
646 DCCP_ACKVEC_STATE_MASK;
647
648 /* new packet received or marked */
649 if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
650 !seqp->ccid2s_acked) {
651 if (state ==
652 DCCP_ACKVEC_STATE_ECN_MARKED) {
653 ccid2_congestion_event(hctx,
654 seqp);
655 } else
656 ccid2_new_ack(sk, seqp,
657 &maxincr);
658
659 seqp->ccid2s_acked = 1;
660 ccid2_pr_debug("Got ack for %llu\n",
661 (unsigned long long)seqp->ccid2s_seq);
662 ccid2_hc_tx_dec_pipe(sk);
663 }
664 if (seqp == hctx->ccid2hctx_seqt) {
665 done = 1;
666 break;
667 }
668 seqp = seqp->ccid2s_next;
669 }
670 if (done)
671 break;
672
673
674 dccp_set_seqno(&ackno, ackno_end_rl - 1);
675 vector++;
676 }
677 if (done)
678 break;
679 }
680
681 /* The state about what is acked should be correct now
682 * Check for NUMDUPACK
683 */
684 seqp = hctx->ccid2hctx_seqt;
685 while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) {
686 seqp = seqp->ccid2s_next;
687 if (seqp == hctx->ccid2hctx_seqh) {
688 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
689 break;
690 }
691 }
692 done = 0;
693 while (1) {
694 if (seqp->ccid2s_acked) {
695 done++;
696 if (done == hctx->ccid2hctx_numdupack)
697 break;
698 }
699 if (seqp == hctx->ccid2hctx_seqt)
700 break;
701 seqp = seqp->ccid2s_prev;
702 }
703
704 /* If there are at least 3 acknowledgements, anything unacknowledged
705 * below the last sequence number is considered lost
706 */
707 if (done == hctx->ccid2hctx_numdupack) {
708 struct ccid2_seq *last_acked = seqp;
709
710 /* check for lost packets */
711 while (1) {
712 if (!seqp->ccid2s_acked) {
713 ccid2_pr_debug("Packet lost: %llu\n",
714 (unsigned long long)seqp->ccid2s_seq);
715 /* XXX need to traverse from tail -> head in
716 * order to detect multiple congestion events in
717 * one ack vector.
718 */
719 ccid2_congestion_event(hctx, seqp);
720 ccid2_hc_tx_dec_pipe(sk);
721 }
722 if (seqp == hctx->ccid2hctx_seqt)
723 break;
724 seqp = seqp->ccid2s_prev;
725 }
726
727 hctx->ccid2hctx_seqt = last_acked;
728 }
729
730 /* trim acked packets in tail */
731 while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
732 if (!hctx->ccid2hctx_seqt->ccid2s_acked)
733 break;
734
735 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
736 }
737
738 ccid2_hc_tx_check_sanity(hctx);
739 }
740
741 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
742 {
743 struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
744
745 ccid2_change_cwnd(hctx, 1);
746 /* Initialize ssthresh to infinity. This means that we will exit the
747 * initial slow-start after the first packet loss. This is what we
748 * want.
749 */
750 hctx->ccid2hctx_ssthresh = ~0;
751 hctx->ccid2hctx_numdupack = 3;
752 hctx->ccid2hctx_seqbufc = 0;
753
754 /* XXX init ~ to window size... */
755 if (ccid2_hc_tx_alloc_seq(hctx))
756 return -ENOMEM;
757
758 hctx->ccid2hctx_sent = 0;
759 hctx->ccid2hctx_rto = 3 * HZ;
760 ccid2_change_srtt(hctx, -1);
761 hctx->ccid2hctx_rttvar = -1;
762 hctx->ccid2hctx_lastrtt = 0;
763 hctx->ccid2hctx_rpdupack = -1;
764 hctx->ccid2hctx_last_cong = jiffies;
765 hctx->ccid2hctx_high_ack = 0;
766
767 hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
768 hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
769 init_timer(&hctx->ccid2hctx_rtotimer);
770
771 ccid2_hc_tx_check_sanity(hctx);
772 return 0;
773 }
774
775 static void ccid2_hc_tx_exit(struct sock *sk)
776 {
777 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
778 int i;
779
780 ccid2_hc_tx_kill_rto_timer(sk);
781
782 for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
783 kfree(hctx->ccid2hctx_seqbuf[i]);
784 hctx->ccid2hctx_seqbufc = 0;
785 }
786
787 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
788 {
789 const struct dccp_sock *dp = dccp_sk(sk);
790 struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
791
792 switch (DCCP_SKB_CB(skb)->dccpd_type) {
793 case DCCP_PKT_DATA:
794 case DCCP_PKT_DATAACK:
795 hcrx->ccid2hcrx_data++;
796 if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
797 dccp_send_ack(sk);
798 hcrx->ccid2hcrx_data = 0;
799 }
800 break;
801 }
802 }
803
804 static struct ccid_operations ccid2 = {
805 .ccid_id = DCCPC_CCID2,
806 .ccid_name = "ccid2",
807 .ccid_owner = THIS_MODULE,
808 .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
809 .ccid_hc_tx_init = ccid2_hc_tx_init,
810 .ccid_hc_tx_exit = ccid2_hc_tx_exit,
811 .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
812 .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
813 .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
814 .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
815 .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
816 };
817
818 #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
819 module_param(ccid2_debug, bool, 0444);
820 MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
821 #endif
822
823 static __init int ccid2_module_init(void)
824 {
825 return ccid_register(&ccid2);
826 }
827 module_init(ccid2_module_init);
828
829 static __exit void ccid2_module_exit(void)
830 {
831 ccid_unregister(&ccid2);
832 }
833 module_exit(ccid2_module_exit);
834
835 MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
836 MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID");
837 MODULE_LICENSE("GPL");
838 MODULE_ALIAS("net-dccp-ccid-2");
Linux kernel - Deliverables
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