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[DCCP] CCID2: Initial CCID2 (TCP-Like) implementation
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / dccp / ccids / ccid2.c
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2a91aa39
AB		 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: draft-ietf-dccp-ccid2-10.txt
27 *
28 * BUGS:
29 * - sequence number wrapping
30 * - jiffies wrapping
31 */
32
33#include <linux/config.h>
34#include "../ccid.h"
35#include "../dccp.h"
36#include "ccid2.h"
37
38static int ccid2_debug;
39
40#if 0
41#define CCID2_DEBUG
42#endif
43
44#ifdef CCID2_DEBUG
45#define ccid2_pr_debug(format, a...) \
46 do { if (ccid2_debug) \
47 printk(KERN_DEBUG "%s: " format, __FUNCTION__, ##a); \
48 } while (0)
49#else
50#define ccid2_pr_debug(format, a...)
51#endif
52
53static const int ccid2_seq_len = 128;
54
55static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
56{
57 return dccp_sk(sk)->dccps_hc_tx_ccid_private;
58}
59
60static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
61{
62 return dccp_sk(sk)->dccps_hc_rx_ccid_private;
63}
64
65#ifdef CCID2_DEBUG
66static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
67{
68 int len = 0;
69 struct ccid2_seq *seqp;
70 int pipe = 0;
71
72 seqp = hctx->ccid2hctx_seqh;
73
74 /* there is data in the chain */
75 if (seqp != hctx->ccid2hctx_seqt) {
76 seqp = seqp->ccid2s_prev;
77 len++;
78 if (!seqp->ccid2s_acked)
79 pipe++;
80
81 while (seqp != hctx->ccid2hctx_seqt) {
82 struct ccid2_seq *prev;
83
84 prev = seqp->ccid2s_prev;
85 len++;
86 if (!prev->ccid2s_acked)
87 pipe++;
88
89 /* packets are sent sequentially */
90 BUG_ON(seqp->ccid2s_seq <= prev->ccid2s_seq);
91 BUG_ON(seqp->ccid2s_sent < prev->ccid2s_sent);
92 BUG_ON(len > ccid2_seq_len);
93
94 seqp = prev;
95 }
96 }
97
98 BUG_ON(pipe != hctx->ccid2hctx_pipe);
99 ccid2_pr_debug("len of chain=%d\n", len);
100
101 do {
102 seqp = seqp->ccid2s_prev;
103 len++;
104 BUG_ON(len > ccid2_seq_len);
105 } while(seqp != hctx->ccid2hctx_seqh);
106
107 BUG_ON(len != ccid2_seq_len);
108 ccid2_pr_debug("total len=%d\n", len);
109}
110#else
111#define ccid2_hc_tx_check_sanity(hctx) do {} while (0)
112#endif
113
114static int ccid2_hc_tx_send_packet(struct sock *sk,
115 struct sk_buff *skb, int len)
116{
117 struct ccid2_hc_tx_sock *hctx;
118
119 switch (DCCP_SKB_CB(skb)->dccpd_type) {
120 case 0: /* XXX data packets from userland come through like this */
121 case DCCP_PKT_DATA:
122 case DCCP_PKT_DATAACK:
123 break;
124 /* No congestion control on other packets */
125 default:
126 return 0;
127 }
128
129 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 100; /* XXX */
143}
144
145static 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 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
170static void ccid2_change_cwnd(struct sock *sk, int val)
171{
172 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
173
174 if (val == 0)
175 val = 1;
176
177 /* XXX do we need to change ack ratio? */
178 ccid2_pr_debug("change cwnd to %d\n", val);
179
180 BUG_ON(val < 1);
181 hctx->ccid2hctx_cwnd = val;
182}
183
184static void ccid2_start_rto_timer(struct sock *sk);
185
186static void ccid2_hc_tx_rto_expire(unsigned long data)
187{
188 struct sock *sk = (struct sock *)data;
189 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
190 long s;
191
192 /* XXX I don't think i'm locking correctly
193 * -sorbo.
194 */
195 bh_lock_sock(sk);
196 if (sock_owned_by_user(sk)) {
197 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
198 jiffies + HZ / 5);
199 goto out;
200 }
201
202 ccid2_pr_debug("RTO_EXPIRE\n");
203
204 ccid2_hc_tx_check_sanity(hctx);
205
206 /* back-off timer */
207 hctx->ccid2hctx_rto <<= 1;
208
209 s = hctx->ccid2hctx_rto / HZ;
210 if (s > 60)
211 hctx->ccid2hctx_rto = 60 * HZ;
212
213 ccid2_start_rto_timer(sk);
214
215 /* adjust pipe, cwnd etc */
216 hctx->ccid2hctx_pipe = 0;
217 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1;
218 if (hctx->ccid2hctx_ssthresh < 2)
219 hctx->ccid2hctx_ssthresh = 2;
220 ccid2_change_cwnd(sk, 1);
221
222 /* clear state about stuff we sent */
223 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
224 hctx->ccid2hctx_ssacks = 0;
225 hctx->ccid2hctx_acks = 0;
226 hctx->ccid2hctx_sent = 0;
227
228 /* clear ack ratio state. */
229 hctx->ccid2hctx_arsent = 0;
230 hctx->ccid2hctx_ackloss = 0;
231 hctx->ccid2hctx_rpseq = 0;
232 hctx->ccid2hctx_rpdupack = -1;
233 ccid2_change_l_ack_ratio(sk, 1);
234 ccid2_hc_tx_check_sanity(hctx);
235out:
236 bh_unlock_sock(sk);
237/* sock_put(sk); */
238}
239
240static void ccid2_start_rto_timer(struct sock *sk)
241{
242 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
243
244 ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
245
246 BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
247 sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
248 jiffies + hctx->ccid2hctx_rto);
249}
250
251static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, int len)
252{
253 struct dccp_sock *dp = dccp_sk(sk);
254 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
255 u64 seq;
256
257 ccid2_hc_tx_check_sanity(hctx);
258
259 BUG_ON(!hctx->ccid2hctx_sendwait);
260 hctx->ccid2hctx_sendwait = 0;
261 hctx->ccid2hctx_pipe++;
262 BUG_ON(hctx->ccid2hctx_pipe < 0);
263
264 /* There is an issue. What if another packet is sent between
265 * packet_send() and packet_sent(). Then the sequence number would be
266 * wrong.
267 * -sorbo.
268 */
269 seq = dp->dccps_gss;
270
271 hctx->ccid2hctx_seqh->ccid2s_seq = seq;
272 hctx->ccid2hctx_seqh->ccid2s_acked = 0;
273 hctx->ccid2hctx_seqh->ccid2s_sent = jiffies;
274 hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqh->ccid2s_next;
275
276 ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
277 hctx->ccid2hctx_pipe);
278
279 if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) {
280 /* XXX allocate more space */
281 WARN_ON(1);
282 }
283
284 hctx->ccid2hctx_sent++;
285
286 /* Ack Ratio. Need to maintain a concept of how many windows we sent */
287 hctx->ccid2hctx_arsent++;
288 /* We had an ack loss in this window... */
289 if (hctx->ccid2hctx_ackloss) {
290 if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
291 hctx->ccid2hctx_arsent = 0;
292 hctx->ccid2hctx_ackloss = 0;
293 }
294 }
295 /* No acks lost up to now... */
296 else {
297 /* decrease ack ratio if enough packets were sent */
298 if (dp->dccps_l_ack_ratio > 1) {
299 /* XXX don't calculate denominator each time */
300 int denom;
301
302 denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
303 dp->dccps_l_ack_ratio;
304 denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
305
306 if (hctx->ccid2hctx_arsent >= denom) {
307 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
308 hctx->ccid2hctx_arsent = 0;
309 }
310 }
311 /* we can't increase ack ratio further [1] */
312 else {
313 hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
314 }
315 }
316
317 /* setup RTO timer */
318 if (!timer_pending(&hctx->ccid2hctx_rtotimer)) {
319 ccid2_start_rto_timer(sk);
320 }
321#ifdef CCID2_DEBUG
322 ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe);
323 ccid2_pr_debug("Sent: seq=%llu\n", seq);
324 do {
325 struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
326
327 while (seqp != hctx->ccid2hctx_seqh) {
328 ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
329 seqp->ccid2s_seq, seqp->ccid2s_acked,
330 seqp->ccid2s_sent);
331 seqp = seqp->ccid2s_next;
332 }
333 } while(0);
334 ccid2_pr_debug("=========\n");
335 ccid2_hc_tx_check_sanity(hctx);
336#endif
337}
338
339/* XXX Lame code duplication!
340 * returns -1 if none was found.
341 * else returns the next offset to use in the function call.
342 */
343static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
344 unsigned char **vec, unsigned char *veclen)
345{
346 const struct dccp_hdr *dh = dccp_hdr(skb);
347 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
348 unsigned char *opt_ptr;
349 const unsigned char *opt_end = (unsigned char *)dh +
350 (dh->dccph_doff * 4);
351 unsigned char opt, len;
352 unsigned char *value;
353
354 BUG_ON(offset < 0);
355 options += offset;
356 opt_ptr = options;
357 if (opt_ptr >= opt_end)
358 return -1;
359
360 while (opt_ptr != opt_end) {
361 opt = *opt_ptr++;
362 len = 0;
363 value = NULL;
364
365 /* Check if this isn't a single byte option */
366 if (opt > DCCPO_MAX_RESERVED) {
367 if (opt_ptr == opt_end)
368 goto out_invalid_option;
369
370 len = *opt_ptr++;
371 if (len < 3)
372 goto out_invalid_option;
373 /*
374 * Remove the type and len fields, leaving
375 * just the value size
376 */
377 len -= 2;
378 value = opt_ptr;
379 opt_ptr += len;
380
381 if (opt_ptr > opt_end)
382 goto out_invalid_option;
383 }
384
385 switch (opt) {
386 case DCCPO_ACK_VECTOR_0:
387 case DCCPO_ACK_VECTOR_1:
388 *vec = value;
389 *veclen = len;
390 return offset + (opt_ptr - options);
391 break;
392 }
393 }
394
395 return -1;
396
397out_invalid_option:
398 BUG_ON(1); /* should never happen... options were previously parsed ! */
399 return -1;
400}
401
402static void ccid2_hc_tx_kill_rto_timer(struct ccid2_hc_tx_sock *hctx)
403{
404 if (del_timer(&hctx->ccid2hctx_rtotimer))
405 ccid2_pr_debug("deleted RTO timer\n");
406}
407
408static inline void ccid2_new_ack(struct sock *sk,
409 struct ccid2_seq *seqp,
410 unsigned int *maxincr)
411{
412 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
413
414 /* slow start */
415 if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
416 hctx->ccid2hctx_acks = 0;
417
418 /* We can increase cwnd at most maxincr [ack_ratio/2] */
419 if (*maxincr) {
420 /* increase every 2 acks */
421 hctx->ccid2hctx_ssacks++;
422 if (hctx->ccid2hctx_ssacks == 2) {
423 ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1);
424 hctx->ccid2hctx_ssacks = 0;
425 *maxincr = *maxincr - 1;
426 }
427 }
428 /* increased cwnd enough for this single ack */
429 else {
430 hctx->ccid2hctx_ssacks = 0;
431 }
432 }
433 else {
434 hctx->ccid2hctx_ssacks = 0;
435 hctx->ccid2hctx_acks++;
436
437 if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
438 ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1);
439 hctx->ccid2hctx_acks = 0;
440 }
441 }
442
443 /* update RTO */
444 if (hctx->ccid2hctx_srtt == -1 ||
445 (jiffies - hctx->ccid2hctx_lastrtt) >= hctx->ccid2hctx_srtt) {
446 unsigned long r = jiffies - seqp->ccid2s_sent;
447 int s;
448
449 /* first measurement */
450 if (hctx->ccid2hctx_srtt == -1) {
451 ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
452 r, jiffies, seqp->ccid2s_seq);
453 hctx->ccid2hctx_srtt = r;
454 hctx->ccid2hctx_rttvar = r >> 1;
455 }
456 else {
457 /* RTTVAR */
458 long tmp = hctx->ccid2hctx_srtt - r;
459 if (tmp < 0)
460 tmp *= -1;
461
462 tmp >>= 2;
463 hctx->ccid2hctx_rttvar *= 3;
464 hctx->ccid2hctx_rttvar >>= 2;
465 hctx->ccid2hctx_rttvar += tmp;
466
467 /* SRTT */
468 hctx->ccid2hctx_srtt *= 7;
469 hctx->ccid2hctx_srtt >>= 3;
470 tmp = r >> 3;
471 hctx->ccid2hctx_srtt += tmp;
472 }
473 s = hctx->ccid2hctx_rttvar << 2;
474 /* clock granularity is 1 when based on jiffies */
475 if (!s)
476 s = 1;
477 hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
478
479 /* must be at least a second */
480 s = hctx->ccid2hctx_rto / HZ;
481 /* DCCP doesn't require this [but I like it cuz my code sux] */
482#if 1
483 if (s < 1)
484 hctx->ccid2hctx_rto = HZ;
485#endif
486 /* max 60 seconds */
487 if (s > 60)
488 hctx->ccid2hctx_rto = HZ * 60;
489
490 hctx->ccid2hctx_lastrtt = jiffies;
491
492 ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
493 hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
494 hctx->ccid2hctx_rto, HZ, r);
495 hctx->ccid2hctx_sent = 0;
496 }
497
498 /* we got a new ack, so re-start RTO timer */
499 ccid2_hc_tx_kill_rto_timer(hctx);
500 ccid2_start_rto_timer(sk);
501}
502
503static void ccid2_hc_tx_dec_pipe(struct ccid2_hc_tx_sock *hctx)
504{
505 hctx->ccid2hctx_pipe--;
506 BUG_ON(hctx->ccid2hctx_pipe < 0);
507
508 if (hctx->ccid2hctx_pipe == 0)
509 ccid2_hc_tx_kill_rto_timer(hctx);
510}
511
512static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
513{
514 struct dccp_sock *dp = dccp_sk(sk);
515 struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
516 u64 ackno, seqno;
517 struct ccid2_seq *seqp;
518 unsigned char *vector;
519 unsigned char veclen;
520 int offset = 0;
521 int done = 0;
522 int loss = 0;
523 unsigned int maxincr = 0;
524
525 ccid2_hc_tx_check_sanity(hctx);
526 /* check reverse path congestion */
527 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
528
529 /* XXX this whole "algorithm" is broken. Need to fix it to keep track
530 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
531 * -sorbo.
532 */
533 /* need to bootstrap */
534 if (hctx->ccid2hctx_rpdupack == -1) {
535 hctx->ccid2hctx_rpdupack = 0;
536 hctx->ccid2hctx_rpseq = seqno;
537 }
538 else {
539 /* check if packet is consecutive */
540 if ((hctx->ccid2hctx_rpseq + 1) == seqno) {
541 hctx->ccid2hctx_rpseq++;
542 }
543 /* it's a later packet */
544 else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
545 hctx->ccid2hctx_rpdupack++;
546
547 /* check if we got enough dupacks */
548 if (hctx->ccid2hctx_rpdupack >=
549 hctx->ccid2hctx_numdupack) {
550
551 hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
552 hctx->ccid2hctx_rpseq = 0;
553
554 ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1);
555 }
556 }
557 }
558
559 /* check forward path congestion */
560 /* still didn't send out new data packets */
561 if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
562 return;
563
564 switch (DCCP_SKB_CB(skb)->dccpd_type) {
565 case DCCP_PKT_ACK:
566 case DCCP_PKT_DATAACK:
567 break;
568
569 default:
570 return;
571 }
572
573 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
574 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
575
576 /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
577 * this single ack. I round up.
578 * -sorbo.
579 */
580 maxincr = dp->dccps_l_ack_ratio >> 1;
581 maxincr++;
582
583 /* go through all ack vectors */
584 while ((offset = ccid2_ackvector(sk, skb, offset,
585 &vector, &veclen)) != -1) {
586 /* go through this ack vector */
587 while (veclen--) {
588 const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
589 u64 ackno_end_rl;
590
591 dccp_set_seqno(&ackno_end_rl, ackno - rl);
592 ccid2_pr_debug("ackvec start:%llu end:%llu\n", ackno,
593 ackno_end_rl);
594 /* if the seqno we are analyzing is larger than the
595 * current ackno, then move towards the tail of our
596 * seqnos.
597 */
598 while (after48(seqp->ccid2s_seq, ackno)) {
599 if (seqp == hctx->ccid2hctx_seqt) {
600 done = 1;
601 break;
602 }
603 seqp = seqp->ccid2s_prev;
604 }
605 if (done)
606 break;
607
608 /* check all seqnos in the range of the vector
609 * run length
610 */
611 while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
612 const u8 state = (*vector &
613 DCCP_ACKVEC_STATE_MASK) >> 6;
614
615 /* new packet received or marked */
616 if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
617 !seqp->ccid2s_acked) {
618 if (state ==
619 DCCP_ACKVEC_STATE_ECN_MARKED) {
620 loss = 1;
621 }
622 else {
623 ccid2_new_ack(sk, seqp,
624 &maxincr);
625 }
626
627 seqp->ccid2s_acked = 1;
628 ccid2_pr_debug("Got ack for %llu\n",
629 seqp->ccid2s_seq);
630 ccid2_hc_tx_dec_pipe(hctx);
631 }
632 if (seqp == hctx->ccid2hctx_seqt) {
633 done = 1;
634 break;
635 }
636 seqp = seqp->ccid2s_next;
637 }
638 if (done)
639 break;
640
641
642 dccp_set_seqno(&ackno, ackno_end_rl - 1);
643 vector++;
644 }
645 if (done)
646 break;
647 }
648
649 /* The state about what is acked should be correct now
650 * Check for NUMDUPACK
651 */
652 seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
653 done = 0;
654 while (1) {
655 if (seqp->ccid2s_acked) {
656 done++;
657 if (done == hctx->ccid2hctx_numdupack) {
658 break;
659 }
660 }
661 if (seqp == hctx->ccid2hctx_seqt) {
662 break;
663 }
664 seqp = seqp->ccid2s_prev;
665 }
666
667 /* If there are at least 3 acknowledgements, anything unacknowledged
668 * below the last sequence number is considered lost
669 */
670 if (done == hctx->ccid2hctx_numdupack) {
671 struct ccid2_seq *last_acked = seqp;
672
673 /* check for lost packets */
674 while (1) {
675 if (!seqp->ccid2s_acked) {
676 loss = 1;
677 ccid2_hc_tx_dec_pipe(hctx);
678 }
679 if (seqp == hctx->ccid2hctx_seqt)
680 break;
681 seqp = seqp->ccid2s_prev;
682 }
683
684 hctx->ccid2hctx_seqt = last_acked;
685 }
686
687 /* trim acked packets in tail */
688 while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
689 if (!hctx->ccid2hctx_seqt->ccid2s_acked)
690 break;
691
692 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
693 }
694
695 if (loss) {
696 /* XXX do bit shifts guarantee a 0 as the new bit? */
697 ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd >> 1);
698 hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd;
699 if (hctx->ccid2hctx_ssthresh < 2)
700 hctx->ccid2hctx_ssthresh = 2;
701 }
702
703 ccid2_hc_tx_check_sanity(hctx);
704}
705
706static int ccid2_hc_tx_init(struct sock *sk)
707{
708 struct dccp_sock *dp = dccp_sk(sk);
709 struct ccid2_hc_tx_sock *hctx;
710 int seqcount = ccid2_seq_len;
711 int i;
712
713 dp->dccps_hc_tx_ccid_private = kzalloc(sizeof(*hctx), gfp_any());
714 if (dp->dccps_hc_tx_ccid_private == NULL)
715 return -ENOMEM;
716
717 hctx = ccid2_hc_tx_sk(sk);
718
719 /* XXX init variables with proper values */
720 hctx->ccid2hctx_cwnd = 1;
721 hctx->ccid2hctx_ssthresh = 10;
722 hctx->ccid2hctx_numdupack = 3;
723
724 /* XXX init ~ to window size... */
725 hctx->ccid2hctx_seqbuf = kmalloc(sizeof(*hctx->ccid2hctx_seqbuf) *
726 seqcount, gfp_any());
727 if (hctx->ccid2hctx_seqbuf == NULL) {
728 kfree(dp->dccps_hc_tx_ccid_private);
729 dp->dccps_hc_tx_ccid_private = NULL;
730 return -ENOMEM;
731 }
732 for (i = 0; i < (seqcount - 1); i++) {
733 hctx->ccid2hctx_seqbuf[i].ccid2s_next =
734 &hctx->ccid2hctx_seqbuf[i + 1];
735 hctx->ccid2hctx_seqbuf[i + 1].ccid2s_prev =
736 &hctx->ccid2hctx_seqbuf[i];
737 }
738 hctx->ccid2hctx_seqbuf[seqcount - 1].ccid2s_next =
739 hctx->ccid2hctx_seqbuf;
740 hctx->ccid2hctx_seqbuf->ccid2s_prev =
741 &hctx->ccid2hctx_seqbuf[seqcount - 1];
742
743 hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqbuf;
744 hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
745 hctx->ccid2hctx_sent = 0;
746 hctx->ccid2hctx_rto = 3 * HZ;
747 hctx->ccid2hctx_srtt = -1;
748 hctx->ccid2hctx_rttvar = -1;
749 hctx->ccid2hctx_lastrtt = 0;
750 hctx->ccid2hctx_rpdupack = -1;
751
752 hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire;
753 hctx->ccid2hctx_rtotimer.data = (unsigned long)sk;
754 init_timer(&hctx->ccid2hctx_rtotimer);
755
756 ccid2_hc_tx_check_sanity(hctx);
757 return 0;
758}
759
760static void ccid2_hc_tx_exit(struct sock *sk)
761{
762 struct dccp_sock *dp = dccp_sk(sk);
763 struct ccid2_hc_tx_sock *hctx = dp->dccps_hc_tx_ccid_private;
764
765 ccid2_hc_tx_kill_rto_timer(hctx);
766
767 kfree(hctx->ccid2hctx_seqbuf);
768
769 kfree(dp->dccps_hc_tx_ccid_private);
770 dp->dccps_hc_tx_ccid_private = NULL;
771}
772
773static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
774{
775 const struct dccp_sock *dp = dccp_sk(sk);
776 struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
777
778 switch (DCCP_SKB_CB(skb)->dccpd_type) {
779 case DCCP_PKT_DATA:
780 case DCCP_PKT_DATAACK:
781 hcrx->ccid2hcrx_data++;
782 if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
783 dccp_send_ack(sk);
784 hcrx->ccid2hcrx_data = 0;
785 }
786 break;
787 }
788}
789
790static int ccid2_hc_rx_init(struct sock *sk)
791{
792 struct dccp_sock *dp = dccp_sk(sk);
793 dp->dccps_hc_rx_ccid_private = kzalloc(sizeof(struct ccid2_hc_rx_sock),
794 gfp_any());
795 return dp->dccps_hc_rx_ccid_private == NULL ? -ENOMEM : 0;
796}
797
798static void ccid2_hc_rx_exit(struct sock *sk)
799{
800 struct dccp_sock *dp = dccp_sk(sk);
801
802 kfree(dp->dccps_hc_rx_ccid_private);
803 dp->dccps_hc_rx_ccid_private = NULL;
804}
805
806static struct ccid ccid2 = {
807 .ccid_id = 2,
808 .ccid_name = "ccid2",
809 .ccid_owner = THIS_MODULE,
810 .ccid_hc_tx_init = ccid2_hc_tx_init,
811 .ccid_hc_tx_exit = ccid2_hc_tx_exit,
812 .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
813 .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
814 .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
815 .ccid_hc_rx_init = ccid2_hc_rx_init,
816 .ccid_hc_rx_exit = ccid2_hc_rx_exit,
817 .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
818};
819
820module_param(ccid2_debug, int, 0444);
821MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
822
823static __init int ccid2_module_init(void)
824{
825 return ccid_register(&ccid2);
826}
827module_init(ccid2_module_init);
828
829static __exit void ccid2_module_exit(void)
830{
831 ccid_unregister(&ccid2);
832}
833module_exit(ccid2_module_exit);
834
835MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
836MODULE_DESCRIPTION("DCCP TCP CCID2 CCID");
837MODULE_LICENSE("GPL");
838MODULE_ALIAS("net-dccp-ccid-2");
kernel source for telekom puls (alcatel/mediatek)