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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 | |
2a91aa39 AB |
30 | */ |
31 | ||
2a91aa39 AB |
32 | #include "../ccid.h" |
33 | #include "../dccp.h" | |
34 | #include "ccid2.h" | |
35 | ||
36 | static int ccid2_debug; | |
37 | ||
c0c736db | 38 | #undef CCID2_DEBUG |
2a91aa39 AB |
39 | #ifdef CCID2_DEBUG |
40 | #define ccid2_pr_debug(format, a...) \ | |
41 | do { if (ccid2_debug) \ | |
42 | printk(KERN_DEBUG "%s: " format, __FUNCTION__, ##a); \ | |
43 | } while (0) | |
44 | #else | |
45 | #define ccid2_pr_debug(format, a...) | |
46 | #endif | |
47 | ||
48 | static const int ccid2_seq_len = 128; | |
49 | ||
2a91aa39 AB |
50 | #ifdef CCID2_DEBUG |
51 | static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) | |
52 | { | |
53 | int len = 0; | |
2a91aa39 | 54 | int pipe = 0; |
c0c736db | 55 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqh; |
2a91aa39 AB |
56 | |
57 | /* there is data in the chain */ | |
58 | if (seqp != hctx->ccid2hctx_seqt) { | |
59 | seqp = seqp->ccid2s_prev; | |
60 | len++; | |
61 | if (!seqp->ccid2s_acked) | |
62 | pipe++; | |
63 | ||
64 | while (seqp != hctx->ccid2hctx_seqt) { | |
c0c736db | 65 | struct ccid2_seq *prev = seqp->ccid2s_prev; |
2a91aa39 | 66 | |
2a91aa39 AB |
67 | len++; |
68 | if (!prev->ccid2s_acked) | |
69 | pipe++; | |
70 | ||
71 | /* packets are sent sequentially */ | |
72 | BUG_ON(seqp->ccid2s_seq <= prev->ccid2s_seq); | |
29651cda AB |
73 | BUG_ON(time_before(seqp->ccid2s_sent, |
74 | prev->ccid2s_sent)); | |
2a91aa39 AB |
75 | BUG_ON(len > ccid2_seq_len); |
76 | ||
77 | seqp = prev; | |
78 | } | |
79 | } | |
80 | ||
81 | BUG_ON(pipe != hctx->ccid2hctx_pipe); | |
82 | ccid2_pr_debug("len of chain=%d\n", len); | |
83 | ||
84 | do { | |
85 | seqp = seqp->ccid2s_prev; | |
86 | len++; | |
87 | BUG_ON(len > ccid2_seq_len); | |
c0c736db | 88 | } while (seqp != hctx->ccid2hctx_seqh); |
2a91aa39 AB |
89 | |
90 | BUG_ON(len != ccid2_seq_len); | |
91 | ccid2_pr_debug("total len=%d\n", len); | |
92 | } | |
93 | #else | |
94 | #define ccid2_hc_tx_check_sanity(hctx) do {} while (0) | |
95 | #endif | |
96 | ||
97 | static int ccid2_hc_tx_send_packet(struct sock *sk, | |
98 | struct sk_buff *skb, int len) | |
99 | { | |
100 | struct ccid2_hc_tx_sock *hctx; | |
101 | ||
102 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
103 | case 0: /* XXX data packets from userland come through like this */ | |
104 | case DCCP_PKT_DATA: | |
105 | case DCCP_PKT_DATAACK: | |
106 | break; | |
107 | /* No congestion control on other packets */ | |
108 | default: | |
109 | return 0; | |
110 | } | |
111 | ||
112 | hctx = ccid2_hc_tx_sk(sk); | |
113 | ||
114 | ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe, | |
115 | hctx->ccid2hctx_cwnd); | |
116 | ||
117 | if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) { | |
118 | /* OK we can send... make sure previous packet was sent off */ | |
119 | if (!hctx->ccid2hctx_sendwait) { | |
120 | hctx->ccid2hctx_sendwait = 1; | |
121 | return 0; | |
122 | } | |
123 | } | |
124 | ||
446dec30 | 125 | return 1; /* XXX CCID should dequeue when ready instead of polling */ |
2a91aa39 AB |
126 | } |
127 | ||
128 | static void ccid2_change_l_ack_ratio(struct sock *sk, int val) | |
129 | { | |
130 | struct dccp_sock *dp = dccp_sk(sk); | |
131 | /* | |
132 | * XXX I don't really agree with val != 2. If cwnd is 1, ack ratio | |
133 | * should be 1... it shouldn't be allowed to become 2. | |
134 | * -sorbo. | |
135 | */ | |
136 | if (val != 2) { | |
c0c736db | 137 | const struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
2a91aa39 AB |
138 | int max = hctx->ccid2hctx_cwnd / 2; |
139 | ||
140 | /* round up */ | |
141 | if (hctx->ccid2hctx_cwnd & 1) | |
142 | max++; | |
143 | ||
144 | if (val > max) | |
145 | val = max; | |
146 | } | |
147 | ||
148 | ccid2_pr_debug("changing local ack ratio to %d\n", val); | |
149 | WARN_ON(val <= 0); | |
150 | dp->dccps_l_ack_ratio = val; | |
151 | } | |
152 | ||
153 | static void ccid2_change_cwnd(struct sock *sk, int val) | |
154 | { | |
155 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
156 | ||
157 | if (val == 0) | |
158 | val = 1; | |
159 | ||
160 | /* XXX do we need to change ack ratio? */ | |
161 | ccid2_pr_debug("change cwnd to %d\n", val); | |
162 | ||
163 | BUG_ON(val < 1); | |
164 | hctx->ccid2hctx_cwnd = val; | |
165 | } | |
166 | ||
167 | static void ccid2_start_rto_timer(struct sock *sk); | |
168 | ||
169 | static void ccid2_hc_tx_rto_expire(unsigned long data) | |
170 | { | |
171 | struct sock *sk = (struct sock *)data; | |
172 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
173 | long s; | |
174 | ||
2a91aa39 AB |
175 | bh_lock_sock(sk); |
176 | if (sock_owned_by_user(sk)) { | |
177 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
178 | jiffies + HZ / 5); | |
179 | goto out; | |
180 | } | |
181 | ||
182 | ccid2_pr_debug("RTO_EXPIRE\n"); | |
183 | ||
184 | ccid2_hc_tx_check_sanity(hctx); | |
185 | ||
186 | /* back-off timer */ | |
187 | hctx->ccid2hctx_rto <<= 1; | |
188 | ||
189 | s = hctx->ccid2hctx_rto / HZ; | |
190 | if (s > 60) | |
191 | hctx->ccid2hctx_rto = 60 * HZ; | |
192 | ||
193 | ccid2_start_rto_timer(sk); | |
194 | ||
195 | /* adjust pipe, cwnd etc */ | |
196 | hctx->ccid2hctx_pipe = 0; | |
197 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1; | |
198 | if (hctx->ccid2hctx_ssthresh < 2) | |
199 | hctx->ccid2hctx_ssthresh = 2; | |
200 | ccid2_change_cwnd(sk, 1); | |
201 | ||
202 | /* clear state about stuff we sent */ | |
203 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; | |
204 | hctx->ccid2hctx_ssacks = 0; | |
205 | hctx->ccid2hctx_acks = 0; | |
206 | hctx->ccid2hctx_sent = 0; | |
207 | ||
208 | /* clear ack ratio state. */ | |
209 | hctx->ccid2hctx_arsent = 0; | |
210 | hctx->ccid2hctx_ackloss = 0; | |
211 | hctx->ccid2hctx_rpseq = 0; | |
212 | hctx->ccid2hctx_rpdupack = -1; | |
213 | ccid2_change_l_ack_ratio(sk, 1); | |
214 | ccid2_hc_tx_check_sanity(hctx); | |
215 | out: | |
216 | bh_unlock_sock(sk); | |
77ff72d5 | 217 | sock_put(sk); |
2a91aa39 AB |
218 | } |
219 | ||
220 | static void ccid2_start_rto_timer(struct sock *sk) | |
221 | { | |
222 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
223 | ||
224 | ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto); | |
225 | ||
226 | BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer)); | |
227 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
228 | jiffies + hctx->ccid2hctx_rto); | |
229 | } | |
230 | ||
231 | static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, int len) | |
232 | { | |
233 | struct dccp_sock *dp = dccp_sk(sk); | |
234 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
235 | u64 seq; | |
236 | ||
237 | ccid2_hc_tx_check_sanity(hctx); | |
238 | ||
239 | BUG_ON(!hctx->ccid2hctx_sendwait); | |
240 | hctx->ccid2hctx_sendwait = 0; | |
241 | hctx->ccid2hctx_pipe++; | |
242 | BUG_ON(hctx->ccid2hctx_pipe < 0); | |
243 | ||
244 | /* There is an issue. What if another packet is sent between | |
245 | * packet_send() and packet_sent(). Then the sequence number would be | |
246 | * wrong. | |
247 | * -sorbo. | |
248 | */ | |
249 | seq = dp->dccps_gss; | |
250 | ||
251 | hctx->ccid2hctx_seqh->ccid2s_seq = seq; | |
252 | hctx->ccid2hctx_seqh->ccid2s_acked = 0; | |
253 | hctx->ccid2hctx_seqh->ccid2s_sent = jiffies; | |
254 | hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqh->ccid2s_next; | |
255 | ||
256 | ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd, | |
257 | hctx->ccid2hctx_pipe); | |
258 | ||
259 | if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) { | |
260 | /* XXX allocate more space */ | |
261 | WARN_ON(1); | |
262 | } | |
263 | ||
264 | hctx->ccid2hctx_sent++; | |
265 | ||
266 | /* Ack Ratio. Need to maintain a concept of how many windows we sent */ | |
267 | hctx->ccid2hctx_arsent++; | |
268 | /* We had an ack loss in this window... */ | |
269 | if (hctx->ccid2hctx_ackloss) { | |
270 | if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) { | |
c0c736db ACM |
271 | hctx->ccid2hctx_arsent = 0; |
272 | hctx->ccid2hctx_ackloss = 0; | |
2a91aa39 | 273 | } |
c0c736db ACM |
274 | } else { |
275 | /* No acks lost up to now... */ | |
2a91aa39 AB |
276 | /* decrease ack ratio if enough packets were sent */ |
277 | if (dp->dccps_l_ack_ratio > 1) { | |
278 | /* XXX don't calculate denominator each time */ | |
c0c736db ACM |
279 | int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio - |
280 | dp->dccps_l_ack_ratio; | |
2a91aa39 | 281 | |
2a91aa39 AB |
282 | denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom; |
283 | ||
284 | if (hctx->ccid2hctx_arsent >= denom) { | |
285 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1); | |
286 | hctx->ccid2hctx_arsent = 0; | |
287 | } | |
c0c736db ACM |
288 | } else { |
289 | /* we can't increase ack ratio further [1] */ | |
2a91aa39 AB |
290 | hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/ |
291 | } | |
292 | } | |
293 | ||
294 | /* setup RTO timer */ | |
c0c736db | 295 | if (!timer_pending(&hctx->ccid2hctx_rtotimer)) |
2a91aa39 | 296 | ccid2_start_rto_timer(sk); |
c0c736db | 297 | |
2a91aa39 AB |
298 | #ifdef CCID2_DEBUG |
299 | ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe); | |
300 | ccid2_pr_debug("Sent: seq=%llu\n", seq); | |
301 | do { | |
302 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqt; | |
303 | ||
304 | while (seqp != hctx->ccid2hctx_seqh) { | |
305 | ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n", | |
306 | seqp->ccid2s_seq, seqp->ccid2s_acked, | |
307 | seqp->ccid2s_sent); | |
308 | seqp = seqp->ccid2s_next; | |
309 | } | |
c0c736db | 310 | } while (0); |
2a91aa39 AB |
311 | ccid2_pr_debug("=========\n"); |
312 | ccid2_hc_tx_check_sanity(hctx); | |
313 | #endif | |
314 | } | |
315 | ||
316 | /* XXX Lame code duplication! | |
317 | * returns -1 if none was found. | |
318 | * else returns the next offset to use in the function call. | |
319 | */ | |
320 | static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset, | |
321 | unsigned char **vec, unsigned char *veclen) | |
322 | { | |
323 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
324 | unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); | |
325 | unsigned char *opt_ptr; | |
326 | const unsigned char *opt_end = (unsigned char *)dh + | |
327 | (dh->dccph_doff * 4); | |
328 | unsigned char opt, len; | |
329 | unsigned char *value; | |
330 | ||
331 | BUG_ON(offset < 0); | |
332 | options += offset; | |
333 | opt_ptr = options; | |
334 | if (opt_ptr >= opt_end) | |
335 | return -1; | |
336 | ||
337 | while (opt_ptr != opt_end) { | |
338 | opt = *opt_ptr++; | |
339 | len = 0; | |
340 | value = NULL; | |
341 | ||
342 | /* Check if this isn't a single byte option */ | |
343 | if (opt > DCCPO_MAX_RESERVED) { | |
344 | if (opt_ptr == opt_end) | |
345 | goto out_invalid_option; | |
346 | ||
347 | len = *opt_ptr++; | |
348 | if (len < 3) | |
349 | goto out_invalid_option; | |
350 | /* | |
351 | * Remove the type and len fields, leaving | |
352 | * just the value size | |
353 | */ | |
354 | len -= 2; | |
355 | value = opt_ptr; | |
356 | opt_ptr += len; | |
357 | ||
358 | if (opt_ptr > opt_end) | |
359 | goto out_invalid_option; | |
360 | } | |
361 | ||
362 | switch (opt) { | |
363 | case DCCPO_ACK_VECTOR_0: | |
364 | case DCCPO_ACK_VECTOR_1: | |
365 | *vec = value; | |
366 | *veclen = len; | |
367 | return offset + (opt_ptr - options); | |
2a91aa39 AB |
368 | } |
369 | } | |
370 | ||
371 | return -1; | |
372 | ||
373 | out_invalid_option: | |
374 | BUG_ON(1); /* should never happen... options were previously parsed ! */ | |
375 | return -1; | |
376 | } | |
377 | ||
77ff72d5 | 378 | static void ccid2_hc_tx_kill_rto_timer(struct sock *sk) |
2a91aa39 | 379 | { |
77ff72d5 AB |
380 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
381 | ||
382 | sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer); | |
383 | ccid2_pr_debug("deleted RTO timer\n"); | |
2a91aa39 AB |
384 | } |
385 | ||
386 | static inline void ccid2_new_ack(struct sock *sk, | |
387 | struct ccid2_seq *seqp, | |
388 | unsigned int *maxincr) | |
389 | { | |
390 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
391 | ||
392 | /* slow start */ | |
393 | if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) { | |
394 | hctx->ccid2hctx_acks = 0; | |
395 | ||
396 | /* We can increase cwnd at most maxincr [ack_ratio/2] */ | |
397 | if (*maxincr) { | |
398 | /* increase every 2 acks */ | |
399 | hctx->ccid2hctx_ssacks++; | |
400 | if (hctx->ccid2hctx_ssacks == 2) { | |
401 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1); | |
402 | hctx->ccid2hctx_ssacks = 0; | |
403 | *maxincr = *maxincr - 1; | |
404 | } | |
c0c736db ACM |
405 | } else { |
406 | /* increased cwnd enough for this single ack */ | |
2a91aa39 AB |
407 | hctx->ccid2hctx_ssacks = 0; |
408 | } | |
c0c736db | 409 | } else { |
2a91aa39 AB |
410 | hctx->ccid2hctx_ssacks = 0; |
411 | hctx->ccid2hctx_acks++; | |
412 | ||
413 | if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) { | |
414 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1); | |
415 | hctx->ccid2hctx_acks = 0; | |
416 | } | |
417 | } | |
418 | ||
419 | /* update RTO */ | |
420 | if (hctx->ccid2hctx_srtt == -1 || | |
29651cda AB |
421 | time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) { |
422 | unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent; | |
2a91aa39 AB |
423 | int s; |
424 | ||
425 | /* first measurement */ | |
426 | if (hctx->ccid2hctx_srtt == -1) { | |
427 | ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n", | |
428 | r, jiffies, seqp->ccid2s_seq); | |
429 | hctx->ccid2hctx_srtt = r; | |
430 | hctx->ccid2hctx_rttvar = r >> 1; | |
c0c736db | 431 | } else { |
2a91aa39 AB |
432 | /* RTTVAR */ |
433 | long tmp = hctx->ccid2hctx_srtt - r; | |
434 | if (tmp < 0) | |
435 | tmp *= -1; | |
436 | ||
437 | tmp >>= 2; | |
438 | hctx->ccid2hctx_rttvar *= 3; | |
439 | hctx->ccid2hctx_rttvar >>= 2; | |
440 | hctx->ccid2hctx_rttvar += tmp; | |
441 | ||
442 | /* SRTT */ | |
443 | hctx->ccid2hctx_srtt *= 7; | |
444 | hctx->ccid2hctx_srtt >>= 3; | |
445 | tmp = r >> 3; | |
446 | hctx->ccid2hctx_srtt += tmp; | |
447 | } | |
448 | s = hctx->ccid2hctx_rttvar << 2; | |
449 | /* clock granularity is 1 when based on jiffies */ | |
450 | if (!s) | |
451 | s = 1; | |
452 | hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s; | |
453 | ||
454 | /* must be at least a second */ | |
455 | s = hctx->ccid2hctx_rto / HZ; | |
456 | /* DCCP doesn't require this [but I like it cuz my code sux] */ | |
457 | #if 1 | |
458 | if (s < 1) | |
459 | hctx->ccid2hctx_rto = HZ; | |
460 | #endif | |
461 | /* max 60 seconds */ | |
462 | if (s > 60) | |
463 | hctx->ccid2hctx_rto = HZ * 60; | |
464 | ||
465 | hctx->ccid2hctx_lastrtt = jiffies; | |
466 | ||
467 | ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n", | |
468 | hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar, | |
469 | hctx->ccid2hctx_rto, HZ, r); | |
470 | hctx->ccid2hctx_sent = 0; | |
471 | } | |
472 | ||
473 | /* we got a new ack, so re-start RTO timer */ | |
77ff72d5 | 474 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
475 | ccid2_start_rto_timer(sk); |
476 | } | |
477 | ||
77ff72d5 | 478 | static void ccid2_hc_tx_dec_pipe(struct sock *sk) |
2a91aa39 | 479 | { |
77ff72d5 AB |
480 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
481 | ||
2a91aa39 AB |
482 | hctx->ccid2hctx_pipe--; |
483 | BUG_ON(hctx->ccid2hctx_pipe < 0); | |
484 | ||
485 | if (hctx->ccid2hctx_pipe == 0) | |
77ff72d5 | 486 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
487 | } |
488 | ||
489 | static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
490 | { | |
491 | struct dccp_sock *dp = dccp_sk(sk); | |
492 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
493 | u64 ackno, seqno; | |
494 | struct ccid2_seq *seqp; | |
495 | unsigned char *vector; | |
496 | unsigned char veclen; | |
497 | int offset = 0; | |
498 | int done = 0; | |
499 | int loss = 0; | |
500 | unsigned int maxincr = 0; | |
501 | ||
502 | ccid2_hc_tx_check_sanity(hctx); | |
503 | /* check reverse path congestion */ | |
504 | seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
505 | ||
506 | /* XXX this whole "algorithm" is broken. Need to fix it to keep track | |
507 | * of the seqnos of the dupacks so that rpseq and rpdupack are correct | |
508 | * -sorbo. | |
509 | */ | |
510 | /* need to bootstrap */ | |
511 | if (hctx->ccid2hctx_rpdupack == -1) { | |
512 | hctx->ccid2hctx_rpdupack = 0; | |
513 | hctx->ccid2hctx_rpseq = seqno; | |
c0c736db | 514 | } else { |
2a91aa39 | 515 | /* check if packet is consecutive */ |
c0c736db | 516 | if ((hctx->ccid2hctx_rpseq + 1) == seqno) |
2a91aa39 | 517 | hctx->ccid2hctx_rpseq++; |
2a91aa39 AB |
518 | /* it's a later packet */ |
519 | else if (after48(seqno, hctx->ccid2hctx_rpseq)) { | |
520 | hctx->ccid2hctx_rpdupack++; | |
521 | ||
522 | /* check if we got enough dupacks */ | |
523 | if (hctx->ccid2hctx_rpdupack >= | |
524 | hctx->ccid2hctx_numdupack) { | |
2a91aa39 AB |
525 | hctx->ccid2hctx_rpdupack = -1; /* XXX lame */ |
526 | hctx->ccid2hctx_rpseq = 0; | |
527 | ||
528 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1); | |
529 | } | |
530 | } | |
531 | } | |
532 | ||
533 | /* check forward path congestion */ | |
534 | /* still didn't send out new data packets */ | |
535 | if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) | |
536 | return; | |
537 | ||
538 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
539 | case DCCP_PKT_ACK: | |
540 | case DCCP_PKT_DATAACK: | |
541 | break; | |
2a91aa39 AB |
542 | default: |
543 | return; | |
544 | } | |
545 | ||
546 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
547 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
548 | ||
549 | /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for | |
550 | * this single ack. I round up. | |
551 | * -sorbo. | |
552 | */ | |
553 | maxincr = dp->dccps_l_ack_ratio >> 1; | |
554 | maxincr++; | |
555 | ||
556 | /* go through all ack vectors */ | |
557 | while ((offset = ccid2_ackvector(sk, skb, offset, | |
558 | &vector, &veclen)) != -1) { | |
559 | /* go through this ack vector */ | |
560 | while (veclen--) { | |
561 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
562 | u64 ackno_end_rl; | |
563 | ||
564 | dccp_set_seqno(&ackno_end_rl, ackno - rl); | |
565 | ccid2_pr_debug("ackvec start:%llu end:%llu\n", ackno, | |
566 | ackno_end_rl); | |
567 | /* if the seqno we are analyzing is larger than the | |
568 | * current ackno, then move towards the tail of our | |
569 | * seqnos. | |
570 | */ | |
571 | while (after48(seqp->ccid2s_seq, ackno)) { | |
572 | if (seqp == hctx->ccid2hctx_seqt) { | |
573 | done = 1; | |
574 | break; | |
575 | } | |
576 | seqp = seqp->ccid2s_prev; | |
577 | } | |
578 | if (done) | |
579 | break; | |
580 | ||
581 | /* check all seqnos in the range of the vector | |
582 | * run length | |
583 | */ | |
584 | while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { | |
8e27e465 AB |
585 | const u8 state = *vector & |
586 | DCCP_ACKVEC_STATE_MASK; | |
2a91aa39 AB |
587 | |
588 | /* new packet received or marked */ | |
589 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && | |
590 | !seqp->ccid2s_acked) { | |
591 | if (state == | |
592 | DCCP_ACKVEC_STATE_ECN_MARKED) { | |
593 | loss = 1; | |
c0c736db | 594 | } else |
2a91aa39 AB |
595 | ccid2_new_ack(sk, seqp, |
596 | &maxincr); | |
2a91aa39 AB |
597 | |
598 | seqp->ccid2s_acked = 1; | |
599 | ccid2_pr_debug("Got ack for %llu\n", | |
600 | seqp->ccid2s_seq); | |
77ff72d5 | 601 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 AB |
602 | } |
603 | if (seqp == hctx->ccid2hctx_seqt) { | |
604 | done = 1; | |
605 | break; | |
606 | } | |
607 | seqp = seqp->ccid2s_next; | |
608 | } | |
609 | if (done) | |
610 | break; | |
611 | ||
612 | ||
613 | dccp_set_seqno(&ackno, ackno_end_rl - 1); | |
614 | vector++; | |
615 | } | |
616 | if (done) | |
617 | break; | |
618 | } | |
619 | ||
620 | /* The state about what is acked should be correct now | |
621 | * Check for NUMDUPACK | |
622 | */ | |
623 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
624 | done = 0; | |
625 | while (1) { | |
626 | if (seqp->ccid2s_acked) { | |
627 | done++; | |
c0c736db | 628 | if (done == hctx->ccid2hctx_numdupack) |
2a91aa39 | 629 | break; |
2a91aa39 | 630 | } |
c0c736db | 631 | if (seqp == hctx->ccid2hctx_seqt) |
2a91aa39 | 632 | break; |
2a91aa39 AB |
633 | seqp = seqp->ccid2s_prev; |
634 | } | |
635 | ||
636 | /* If there are at least 3 acknowledgements, anything unacknowledged | |
637 | * below the last sequence number is considered lost | |
638 | */ | |
639 | if (done == hctx->ccid2hctx_numdupack) { | |
640 | struct ccid2_seq *last_acked = seqp; | |
641 | ||
642 | /* check for lost packets */ | |
643 | while (1) { | |
644 | if (!seqp->ccid2s_acked) { | |
645 | loss = 1; | |
77ff72d5 | 646 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 AB |
647 | } |
648 | if (seqp == hctx->ccid2hctx_seqt) | |
649 | break; | |
650 | seqp = seqp->ccid2s_prev; | |
651 | } | |
652 | ||
653 | hctx->ccid2hctx_seqt = last_acked; | |
654 | } | |
655 | ||
656 | /* trim acked packets in tail */ | |
657 | while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) { | |
658 | if (!hctx->ccid2hctx_seqt->ccid2s_acked) | |
659 | break; | |
660 | ||
661 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next; | |
662 | } | |
663 | ||
664 | if (loss) { | |
665 | /* XXX do bit shifts guarantee a 0 as the new bit? */ | |
666 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd >> 1); | |
667 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd; | |
668 | if (hctx->ccid2hctx_ssthresh < 2) | |
669 | hctx->ccid2hctx_ssthresh = 2; | |
670 | } | |
671 | ||
672 | ccid2_hc_tx_check_sanity(hctx); | |
673 | } | |
674 | ||
91f0ebf7 | 675 | static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) |
2a91aa39 | 676 | { |
91f0ebf7 | 677 | struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid); |
2a91aa39 AB |
678 | int seqcount = ccid2_seq_len; |
679 | int i; | |
680 | ||
2a91aa39 | 681 | hctx->ccid2hctx_cwnd = 1; |
d458c25c AB |
682 | /* Initialize ssthresh to infinity. This means that we will exit the |
683 | * initial slow-start after the first packet loss. This is what we | |
684 | * want. | |
685 | */ | |
686 | hctx->ccid2hctx_ssthresh = ~0; | |
2a91aa39 AB |
687 | hctx->ccid2hctx_numdupack = 3; |
688 | ||
689 | /* XXX init ~ to window size... */ | |
690 | hctx->ccid2hctx_seqbuf = kmalloc(sizeof(*hctx->ccid2hctx_seqbuf) * | |
691 | seqcount, gfp_any()); | |
91f0ebf7 | 692 | if (hctx->ccid2hctx_seqbuf == NULL) |
2a91aa39 | 693 | return -ENOMEM; |
91f0ebf7 | 694 | |
2a91aa39 AB |
695 | for (i = 0; i < (seqcount - 1); i++) { |
696 | hctx->ccid2hctx_seqbuf[i].ccid2s_next = | |
697 | &hctx->ccid2hctx_seqbuf[i + 1]; | |
698 | hctx->ccid2hctx_seqbuf[i + 1].ccid2s_prev = | |
699 | &hctx->ccid2hctx_seqbuf[i]; | |
700 | } | |
701 | hctx->ccid2hctx_seqbuf[seqcount - 1].ccid2s_next = | |
702 | hctx->ccid2hctx_seqbuf; | |
703 | hctx->ccid2hctx_seqbuf->ccid2s_prev = | |
704 | &hctx->ccid2hctx_seqbuf[seqcount - 1]; | |
705 | ||
706 | hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqbuf; | |
707 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; | |
708 | hctx->ccid2hctx_sent = 0; | |
709 | hctx->ccid2hctx_rto = 3 * HZ; | |
710 | hctx->ccid2hctx_srtt = -1; | |
711 | hctx->ccid2hctx_rttvar = -1; | |
712 | hctx->ccid2hctx_lastrtt = 0; | |
713 | hctx->ccid2hctx_rpdupack = -1; | |
714 | ||
715 | hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire; | |
716 | hctx->ccid2hctx_rtotimer.data = (unsigned long)sk; | |
717 | init_timer(&hctx->ccid2hctx_rtotimer); | |
718 | ||
719 | ccid2_hc_tx_check_sanity(hctx); | |
720 | return 0; | |
721 | } | |
722 | ||
723 | static void ccid2_hc_tx_exit(struct sock *sk) | |
724 | { | |
77ff72d5 | 725 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
2a91aa39 | 726 | |
77ff72d5 | 727 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 | 728 | kfree(hctx->ccid2hctx_seqbuf); |
91f0ebf7 | 729 | hctx->ccid2hctx_seqbuf = NULL; |
2a91aa39 AB |
730 | } |
731 | ||
732 | static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
733 | { | |
734 | const struct dccp_sock *dp = dccp_sk(sk); | |
735 | struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk); | |
736 | ||
737 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
738 | case DCCP_PKT_DATA: | |
739 | case DCCP_PKT_DATAACK: | |
740 | hcrx->ccid2hcrx_data++; | |
741 | if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) { | |
742 | dccp_send_ack(sk); | |
743 | hcrx->ccid2hcrx_data = 0; | |
744 | } | |
745 | break; | |
746 | } | |
747 | } | |
748 | ||
91f0ebf7 | 749 | static struct ccid_operations ccid2 = { |
2a91aa39 AB |
750 | .ccid_id = 2, |
751 | .ccid_name = "ccid2", | |
752 | .ccid_owner = THIS_MODULE, | |
91f0ebf7 | 753 | .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), |
2a91aa39 AB |
754 | .ccid_hc_tx_init = ccid2_hc_tx_init, |
755 | .ccid_hc_tx_exit = ccid2_hc_tx_exit, | |
756 | .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, | |
757 | .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, | |
758 | .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, | |
91f0ebf7 | 759 | .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), |
2a91aa39 AB |
760 | .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, |
761 | }; | |
762 | ||
763 | module_param(ccid2_debug, int, 0444); | |
764 | MODULE_PARM_DESC(ccid2_debug, "Enable debug messages"); | |
765 | ||
766 | static __init int ccid2_module_init(void) | |
767 | { | |
768 | return ccid_register(&ccid2); | |
769 | } | |
770 | module_init(ccid2_module_init); | |
771 | ||
772 | static __exit void ccid2_module_exit(void) | |
773 | { | |
774 | ccid_unregister(&ccid2); | |
775 | } | |
776 | module_exit(ccid2_module_exit); | |
777 | ||
778 | MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>"); | |
c0c736db | 779 | MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID"); |
2a91aa39 AB |
780 | MODULE_LICENSE("GPL"); |
781 | MODULE_ALIAS("net-dccp-ccid-2"); |