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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); | |
77ff72d5 | 237 | sock_put(sk); |
2a91aa39 AB |
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 | ||
77ff72d5 | 402 | static void ccid2_hc_tx_kill_rto_timer(struct sock *sk) |
2a91aa39 | 403 | { |
77ff72d5 AB |
404 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
405 | ||
406 | sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer); | |
407 | ccid2_pr_debug("deleted RTO timer\n"); | |
2a91aa39 AB |
408 | } |
409 | ||
410 | static inline void ccid2_new_ack(struct sock *sk, | |
411 | struct ccid2_seq *seqp, | |
412 | unsigned int *maxincr) | |
413 | { | |
414 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
415 | ||
416 | /* slow start */ | |
417 | if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) { | |
418 | hctx->ccid2hctx_acks = 0; | |
419 | ||
420 | /* We can increase cwnd at most maxincr [ack_ratio/2] */ | |
421 | if (*maxincr) { | |
422 | /* increase every 2 acks */ | |
423 | hctx->ccid2hctx_ssacks++; | |
424 | if (hctx->ccid2hctx_ssacks == 2) { | |
425 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1); | |
426 | hctx->ccid2hctx_ssacks = 0; | |
427 | *maxincr = *maxincr - 1; | |
428 | } | |
429 | } | |
430 | /* increased cwnd enough for this single ack */ | |
431 | else { | |
432 | hctx->ccid2hctx_ssacks = 0; | |
433 | } | |
434 | } | |
435 | else { | |
436 | hctx->ccid2hctx_ssacks = 0; | |
437 | hctx->ccid2hctx_acks++; | |
438 | ||
439 | if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) { | |
440 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1); | |
441 | hctx->ccid2hctx_acks = 0; | |
442 | } | |
443 | } | |
444 | ||
445 | /* update RTO */ | |
446 | if (hctx->ccid2hctx_srtt == -1 || | |
447 | (jiffies - hctx->ccid2hctx_lastrtt) >= hctx->ccid2hctx_srtt) { | |
448 | unsigned long r = jiffies - seqp->ccid2s_sent; | |
449 | int s; | |
450 | ||
451 | /* first measurement */ | |
452 | if (hctx->ccid2hctx_srtt == -1) { | |
453 | ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n", | |
454 | r, jiffies, seqp->ccid2s_seq); | |
455 | hctx->ccid2hctx_srtt = r; | |
456 | hctx->ccid2hctx_rttvar = r >> 1; | |
457 | } | |
458 | else { | |
459 | /* RTTVAR */ | |
460 | long tmp = hctx->ccid2hctx_srtt - r; | |
461 | if (tmp < 0) | |
462 | tmp *= -1; | |
463 | ||
464 | tmp >>= 2; | |
465 | hctx->ccid2hctx_rttvar *= 3; | |
466 | hctx->ccid2hctx_rttvar >>= 2; | |
467 | hctx->ccid2hctx_rttvar += tmp; | |
468 | ||
469 | /* SRTT */ | |
470 | hctx->ccid2hctx_srtt *= 7; | |
471 | hctx->ccid2hctx_srtt >>= 3; | |
472 | tmp = r >> 3; | |
473 | hctx->ccid2hctx_srtt += tmp; | |
474 | } | |
475 | s = hctx->ccid2hctx_rttvar << 2; | |
476 | /* clock granularity is 1 when based on jiffies */ | |
477 | if (!s) | |
478 | s = 1; | |
479 | hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s; | |
480 | ||
481 | /* must be at least a second */ | |
482 | s = hctx->ccid2hctx_rto / HZ; | |
483 | /* DCCP doesn't require this [but I like it cuz my code sux] */ | |
484 | #if 1 | |
485 | if (s < 1) | |
486 | hctx->ccid2hctx_rto = HZ; | |
487 | #endif | |
488 | /* max 60 seconds */ | |
489 | if (s > 60) | |
490 | hctx->ccid2hctx_rto = HZ * 60; | |
491 | ||
492 | hctx->ccid2hctx_lastrtt = jiffies; | |
493 | ||
494 | ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n", | |
495 | hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar, | |
496 | hctx->ccid2hctx_rto, HZ, r); | |
497 | hctx->ccid2hctx_sent = 0; | |
498 | } | |
499 | ||
500 | /* we got a new ack, so re-start RTO timer */ | |
77ff72d5 | 501 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
502 | ccid2_start_rto_timer(sk); |
503 | } | |
504 | ||
77ff72d5 | 505 | static void ccid2_hc_tx_dec_pipe(struct sock *sk) |
2a91aa39 | 506 | { |
77ff72d5 AB |
507 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
508 | ||
2a91aa39 AB |
509 | hctx->ccid2hctx_pipe--; |
510 | BUG_ON(hctx->ccid2hctx_pipe < 0); | |
511 | ||
512 | if (hctx->ccid2hctx_pipe == 0) | |
77ff72d5 | 513 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
514 | } |
515 | ||
516 | static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
517 | { | |
518 | struct dccp_sock *dp = dccp_sk(sk); | |
519 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
520 | u64 ackno, seqno; | |
521 | struct ccid2_seq *seqp; | |
522 | unsigned char *vector; | |
523 | unsigned char veclen; | |
524 | int offset = 0; | |
525 | int done = 0; | |
526 | int loss = 0; | |
527 | unsigned int maxincr = 0; | |
528 | ||
529 | ccid2_hc_tx_check_sanity(hctx); | |
530 | /* check reverse path congestion */ | |
531 | seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
532 | ||
533 | /* XXX this whole "algorithm" is broken. Need to fix it to keep track | |
534 | * of the seqnos of the dupacks so that rpseq and rpdupack are correct | |
535 | * -sorbo. | |
536 | */ | |
537 | /* need to bootstrap */ | |
538 | if (hctx->ccid2hctx_rpdupack == -1) { | |
539 | hctx->ccid2hctx_rpdupack = 0; | |
540 | hctx->ccid2hctx_rpseq = seqno; | |
541 | } | |
542 | else { | |
543 | /* check if packet is consecutive */ | |
544 | if ((hctx->ccid2hctx_rpseq + 1) == seqno) { | |
545 | hctx->ccid2hctx_rpseq++; | |
546 | } | |
547 | /* it's a later packet */ | |
548 | else if (after48(seqno, hctx->ccid2hctx_rpseq)) { | |
549 | hctx->ccid2hctx_rpdupack++; | |
550 | ||
551 | /* check if we got enough dupacks */ | |
552 | if (hctx->ccid2hctx_rpdupack >= | |
553 | hctx->ccid2hctx_numdupack) { | |
554 | ||
555 | hctx->ccid2hctx_rpdupack = -1; /* XXX lame */ | |
556 | hctx->ccid2hctx_rpseq = 0; | |
557 | ||
558 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1); | |
559 | } | |
560 | } | |
561 | } | |
562 | ||
563 | /* check forward path congestion */ | |
564 | /* still didn't send out new data packets */ | |
565 | if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) | |
566 | return; | |
567 | ||
568 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
569 | case DCCP_PKT_ACK: | |
570 | case DCCP_PKT_DATAACK: | |
571 | break; | |
572 | ||
573 | default: | |
574 | return; | |
575 | } | |
576 | ||
577 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
578 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
579 | ||
580 | /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for | |
581 | * this single ack. I round up. | |
582 | * -sorbo. | |
583 | */ | |
584 | maxincr = dp->dccps_l_ack_ratio >> 1; | |
585 | maxincr++; | |
586 | ||
587 | /* go through all ack vectors */ | |
588 | while ((offset = ccid2_ackvector(sk, skb, offset, | |
589 | &vector, &veclen)) != -1) { | |
590 | /* go through this ack vector */ | |
591 | while (veclen--) { | |
592 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
593 | u64 ackno_end_rl; | |
594 | ||
595 | dccp_set_seqno(&ackno_end_rl, ackno - rl); | |
596 | ccid2_pr_debug("ackvec start:%llu end:%llu\n", ackno, | |
597 | ackno_end_rl); | |
598 | /* if the seqno we are analyzing is larger than the | |
599 | * current ackno, then move towards the tail of our | |
600 | * seqnos. | |
601 | */ | |
602 | while (after48(seqp->ccid2s_seq, ackno)) { | |
603 | if (seqp == hctx->ccid2hctx_seqt) { | |
604 | done = 1; | |
605 | break; | |
606 | } | |
607 | seqp = seqp->ccid2s_prev; | |
608 | } | |
609 | if (done) | |
610 | break; | |
611 | ||
612 | /* check all seqnos in the range of the vector | |
613 | * run length | |
614 | */ | |
615 | while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { | |
616 | const u8 state = (*vector & | |
617 | DCCP_ACKVEC_STATE_MASK) >> 6; | |
618 | ||
619 | /* new packet received or marked */ | |
620 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && | |
621 | !seqp->ccid2s_acked) { | |
622 | if (state == | |
623 | DCCP_ACKVEC_STATE_ECN_MARKED) { | |
624 | loss = 1; | |
625 | } | |
626 | else { | |
627 | ccid2_new_ack(sk, seqp, | |
628 | &maxincr); | |
629 | } | |
630 | ||
631 | seqp->ccid2s_acked = 1; | |
632 | ccid2_pr_debug("Got ack for %llu\n", | |
633 | seqp->ccid2s_seq); | |
77ff72d5 | 634 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 AB |
635 | } |
636 | if (seqp == hctx->ccid2hctx_seqt) { | |
637 | done = 1; | |
638 | break; | |
639 | } | |
640 | seqp = seqp->ccid2s_next; | |
641 | } | |
642 | if (done) | |
643 | break; | |
644 | ||
645 | ||
646 | dccp_set_seqno(&ackno, ackno_end_rl - 1); | |
647 | vector++; | |
648 | } | |
649 | if (done) | |
650 | break; | |
651 | } | |
652 | ||
653 | /* The state about what is acked should be correct now | |
654 | * Check for NUMDUPACK | |
655 | */ | |
656 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
657 | done = 0; | |
658 | while (1) { | |
659 | if (seqp->ccid2s_acked) { | |
660 | done++; | |
661 | if (done == hctx->ccid2hctx_numdupack) { | |
662 | break; | |
663 | } | |
664 | } | |
665 | if (seqp == hctx->ccid2hctx_seqt) { | |
666 | break; | |
667 | } | |
668 | seqp = seqp->ccid2s_prev; | |
669 | } | |
670 | ||
671 | /* If there are at least 3 acknowledgements, anything unacknowledged | |
672 | * below the last sequence number is considered lost | |
673 | */ | |
674 | if (done == hctx->ccid2hctx_numdupack) { | |
675 | struct ccid2_seq *last_acked = seqp; | |
676 | ||
677 | /* check for lost packets */ | |
678 | while (1) { | |
679 | if (!seqp->ccid2s_acked) { | |
680 | loss = 1; | |
77ff72d5 | 681 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 AB |
682 | } |
683 | if (seqp == hctx->ccid2hctx_seqt) | |
684 | break; | |
685 | seqp = seqp->ccid2s_prev; | |
686 | } | |
687 | ||
688 | hctx->ccid2hctx_seqt = last_acked; | |
689 | } | |
690 | ||
691 | /* trim acked packets in tail */ | |
692 | while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) { | |
693 | if (!hctx->ccid2hctx_seqt->ccid2s_acked) | |
694 | break; | |
695 | ||
696 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next; | |
697 | } | |
698 | ||
699 | if (loss) { | |
700 | /* XXX do bit shifts guarantee a 0 as the new bit? */ | |
701 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd >> 1); | |
702 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd; | |
703 | if (hctx->ccid2hctx_ssthresh < 2) | |
704 | hctx->ccid2hctx_ssthresh = 2; | |
705 | } | |
706 | ||
707 | ccid2_hc_tx_check_sanity(hctx); | |
708 | } | |
709 | ||
710 | static int ccid2_hc_tx_init(struct sock *sk) | |
711 | { | |
712 | struct dccp_sock *dp = dccp_sk(sk); | |
713 | struct ccid2_hc_tx_sock *hctx; | |
714 | int seqcount = ccid2_seq_len; | |
715 | int i; | |
716 | ||
717 | dp->dccps_hc_tx_ccid_private = kzalloc(sizeof(*hctx), gfp_any()); | |
718 | if (dp->dccps_hc_tx_ccid_private == NULL) | |
719 | return -ENOMEM; | |
720 | ||
721 | hctx = ccid2_hc_tx_sk(sk); | |
722 | ||
723 | /* XXX init variables with proper values */ | |
724 | hctx->ccid2hctx_cwnd = 1; | |
725 | hctx->ccid2hctx_ssthresh = 10; | |
726 | hctx->ccid2hctx_numdupack = 3; | |
727 | ||
728 | /* XXX init ~ to window size... */ | |
729 | hctx->ccid2hctx_seqbuf = kmalloc(sizeof(*hctx->ccid2hctx_seqbuf) * | |
730 | seqcount, gfp_any()); | |
731 | if (hctx->ccid2hctx_seqbuf == NULL) { | |
732 | kfree(dp->dccps_hc_tx_ccid_private); | |
733 | dp->dccps_hc_tx_ccid_private = NULL; | |
734 | return -ENOMEM; | |
735 | } | |
736 | for (i = 0; i < (seqcount - 1); i++) { | |
737 | hctx->ccid2hctx_seqbuf[i].ccid2s_next = | |
738 | &hctx->ccid2hctx_seqbuf[i + 1]; | |
739 | hctx->ccid2hctx_seqbuf[i + 1].ccid2s_prev = | |
740 | &hctx->ccid2hctx_seqbuf[i]; | |
741 | } | |
742 | hctx->ccid2hctx_seqbuf[seqcount - 1].ccid2s_next = | |
743 | hctx->ccid2hctx_seqbuf; | |
744 | hctx->ccid2hctx_seqbuf->ccid2s_prev = | |
745 | &hctx->ccid2hctx_seqbuf[seqcount - 1]; | |
746 | ||
747 | hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqbuf; | |
748 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; | |
749 | hctx->ccid2hctx_sent = 0; | |
750 | hctx->ccid2hctx_rto = 3 * HZ; | |
751 | hctx->ccid2hctx_srtt = -1; | |
752 | hctx->ccid2hctx_rttvar = -1; | |
753 | hctx->ccid2hctx_lastrtt = 0; | |
754 | hctx->ccid2hctx_rpdupack = -1; | |
755 | ||
756 | hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire; | |
757 | hctx->ccid2hctx_rtotimer.data = (unsigned long)sk; | |
758 | init_timer(&hctx->ccid2hctx_rtotimer); | |
759 | ||
760 | ccid2_hc_tx_check_sanity(hctx); | |
761 | return 0; | |
762 | } | |
763 | ||
764 | static void ccid2_hc_tx_exit(struct sock *sk) | |
765 | { | |
766 | struct dccp_sock *dp = dccp_sk(sk); | |
77ff72d5 | 767 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
2a91aa39 | 768 | |
77ff72d5 | 769 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
770 | |
771 | kfree(hctx->ccid2hctx_seqbuf); | |
772 | ||
773 | kfree(dp->dccps_hc_tx_ccid_private); | |
774 | dp->dccps_hc_tx_ccid_private = NULL; | |
775 | } | |
776 | ||
777 | static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
778 | { | |
779 | const struct dccp_sock *dp = dccp_sk(sk); | |
780 | struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk); | |
781 | ||
782 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
783 | case DCCP_PKT_DATA: | |
784 | case DCCP_PKT_DATAACK: | |
785 | hcrx->ccid2hcrx_data++; | |
786 | if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) { | |
787 | dccp_send_ack(sk); | |
788 | hcrx->ccid2hcrx_data = 0; | |
789 | } | |
790 | break; | |
791 | } | |
792 | } | |
793 | ||
794 | static int ccid2_hc_rx_init(struct sock *sk) | |
795 | { | |
796 | struct dccp_sock *dp = dccp_sk(sk); | |
797 | dp->dccps_hc_rx_ccid_private = kzalloc(sizeof(struct ccid2_hc_rx_sock), | |
798 | gfp_any()); | |
799 | return dp->dccps_hc_rx_ccid_private == NULL ? -ENOMEM : 0; | |
800 | } | |
801 | ||
802 | static void ccid2_hc_rx_exit(struct sock *sk) | |
803 | { | |
804 | struct dccp_sock *dp = dccp_sk(sk); | |
805 | ||
806 | kfree(dp->dccps_hc_rx_ccid_private); | |
807 | dp->dccps_hc_rx_ccid_private = NULL; | |
808 | } | |
809 | ||
810 | static struct ccid ccid2 = { | |
811 | .ccid_id = 2, | |
812 | .ccid_name = "ccid2", | |
813 | .ccid_owner = THIS_MODULE, | |
814 | .ccid_hc_tx_init = ccid2_hc_tx_init, | |
815 | .ccid_hc_tx_exit = ccid2_hc_tx_exit, | |
816 | .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, | |
817 | .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, | |
818 | .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, | |
819 | .ccid_hc_rx_init = ccid2_hc_rx_init, | |
820 | .ccid_hc_rx_exit = ccid2_hc_rx_exit, | |
821 | .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, | |
822 | }; | |
823 | ||
824 | module_param(ccid2_debug, int, 0444); | |
825 | MODULE_PARM_DESC(ccid2_debug, "Enable debug messages"); | |
826 | ||
827 | static __init int ccid2_module_init(void) | |
828 | { | |
829 | return ccid_register(&ccid2); | |
830 | } | |
831 | module_init(ccid2_module_init); | |
832 | ||
833 | static __exit void ccid2_module_exit(void) | |
834 | { | |
835 | ccid_unregister(&ccid2); | |
836 | } | |
837 | module_exit(ccid2_module_exit); | |
838 | ||
839 | MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>"); | |
840 | MODULE_DESCRIPTION("DCCP TCP CCID2 CCID"); | |
841 | MODULE_LICENSE("GPL"); | |
842 | MODULE_ALIAS("net-dccp-ccid-2"); |