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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 | ||
38 | static 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 | ||
53 | static const int ccid2_seq_len = 128; | |
54 | ||
55 | static 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 | ||
60 | static 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 | |
66 | static 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 | ||
114 | static 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 | ||
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 | 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 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 | ||
184 | static void ccid2_start_rto_timer(struct sock *sk); | |
185 | ||
186 | static 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); | |
235 | out: | |
236 | bh_unlock_sock(sk); | |
237 | /* sock_put(sk); */ | |
238 | } | |
239 | ||
240 | static 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 | ||
251 | static 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 | */ | |
343 | static 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 | ||
397 | out_invalid_option: | |
398 | BUG_ON(1); /* should never happen... options were previously parsed ! */ | |
399 | return -1; | |
400 | } | |
401 | ||
402 | static 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 | ||
408 | static 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 | ||
503 | static 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 | ||
512 | static 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 | ||
706 | static 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 | ||
760 | static 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 | ||
773 | static 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 | ||
790 | static 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 | ||
798 | static 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 | ||
806 | static 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 | ||
820 | module_param(ccid2_debug, int, 0444); | |
821 | MODULE_PARM_DESC(ccid2_debug, "Enable debug messages"); | |
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 CCID2 CCID"); | |
837 | MODULE_LICENSE("GPL"); | |
838 | MODULE_ALIAS("net-dccp-ccid-2"); |