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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 | ||
8d424f6c | 38 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
2a91aa39 AB |
39 | #define ccid2_pr_debug(format, a...) \ |
40 | do { if (ccid2_debug) \ | |
41 | printk(KERN_DEBUG "%s: " format, __FUNCTION__, ##a); \ | |
42 | } while (0) | |
43 | #else | |
44 | #define ccid2_pr_debug(format, a...) | |
45 | #endif | |
46 | ||
8d424f6c | 47 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
2a91aa39 AB |
48 | static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) |
49 | { | |
50 | int len = 0; | |
2a91aa39 | 51 | int pipe = 0; |
c0c736db | 52 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqh; |
2a91aa39 AB |
53 | |
54 | /* there is data in the chain */ | |
55 | if (seqp != hctx->ccid2hctx_seqt) { | |
56 | seqp = seqp->ccid2s_prev; | |
57 | len++; | |
58 | if (!seqp->ccid2s_acked) | |
59 | pipe++; | |
60 | ||
61 | while (seqp != hctx->ccid2hctx_seqt) { | |
c0c736db | 62 | struct ccid2_seq *prev = seqp->ccid2s_prev; |
2a91aa39 | 63 | |
2a91aa39 AB |
64 | len++; |
65 | if (!prev->ccid2s_acked) | |
66 | pipe++; | |
67 | ||
68 | /* packets are sent sequentially */ | |
69 | BUG_ON(seqp->ccid2s_seq <= prev->ccid2s_seq); | |
29651cda AB |
70 | BUG_ON(time_before(seqp->ccid2s_sent, |
71 | prev->ccid2s_sent)); | |
2a91aa39 AB |
72 | |
73 | seqp = prev; | |
74 | } | |
75 | } | |
76 | ||
77 | BUG_ON(pipe != hctx->ccid2hctx_pipe); | |
78 | ccid2_pr_debug("len of chain=%d\n", len); | |
79 | ||
80 | do { | |
81 | seqp = seqp->ccid2s_prev; | |
82 | len++; | |
c0c736db | 83 | } while (seqp != hctx->ccid2hctx_seqh); |
2a91aa39 | 84 | |
2a91aa39 | 85 | ccid2_pr_debug("total len=%d\n", len); |
07978aab | 86 | BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN); |
2a91aa39 AB |
87 | } |
88 | #else | |
89 | #define ccid2_hc_tx_check_sanity(hctx) do {} while (0) | |
90 | #endif | |
91 | ||
07978aab AB |
92 | static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx, int num, |
93 | gfp_t gfp) | |
94 | { | |
95 | struct ccid2_seq *seqp; | |
96 | int i; | |
97 | ||
98 | /* check if we have space to preserve the pointer to the buffer */ | |
99 | if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) / | |
100 | sizeof(struct ccid2_seq*))) | |
101 | return -ENOMEM; | |
102 | ||
103 | /* allocate buffer and initialize linked list */ | |
104 | seqp = kmalloc(sizeof(*seqp) * num, gfp); | |
105 | if (seqp == NULL) | |
106 | return -ENOMEM; | |
107 | ||
108 | for (i = 0; i < (num - 1); i++) { | |
109 | seqp[i].ccid2s_next = &seqp[i + 1]; | |
110 | seqp[i + 1].ccid2s_prev = &seqp[i]; | |
111 | } | |
112 | seqp[num - 1].ccid2s_next = seqp; | |
113 | seqp->ccid2s_prev = &seqp[num - 1]; | |
114 | ||
115 | /* This is the first allocation. Initiate the head and tail. */ | |
116 | if (hctx->ccid2hctx_seqbufc == 0) | |
117 | hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp; | |
118 | else { | |
119 | /* link the existing list with the one we just created */ | |
120 | hctx->ccid2hctx_seqh->ccid2s_next = seqp; | |
121 | seqp->ccid2s_prev = hctx->ccid2hctx_seqh; | |
122 | ||
123 | hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[num - 1]; | |
124 | seqp[num - 1].ccid2s_next = hctx->ccid2hctx_seqt; | |
125 | } | |
126 | ||
127 | /* store the original pointer to the buffer so we can free it */ | |
128 | hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp; | |
129 | hctx->ccid2hctx_seqbufc++; | |
130 | ||
131 | return 0; | |
132 | } | |
133 | ||
2a91aa39 AB |
134 | static int ccid2_hc_tx_send_packet(struct sock *sk, |
135 | struct sk_buff *skb, int len) | |
136 | { | |
137 | struct ccid2_hc_tx_sock *hctx; | |
138 | ||
139 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
140 | case 0: /* XXX data packets from userland come through like this */ | |
141 | case DCCP_PKT_DATA: | |
142 | case DCCP_PKT_DATAACK: | |
143 | break; | |
144 | /* No congestion control on other packets */ | |
145 | default: | |
146 | return 0; | |
147 | } | |
148 | ||
149 | hctx = ccid2_hc_tx_sk(sk); | |
150 | ||
151 | ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe, | |
152 | hctx->ccid2hctx_cwnd); | |
153 | ||
154 | if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) { | |
155 | /* OK we can send... make sure previous packet was sent off */ | |
156 | if (!hctx->ccid2hctx_sendwait) { | |
157 | hctx->ccid2hctx_sendwait = 1; | |
158 | return 0; | |
159 | } | |
160 | } | |
161 | ||
446dec30 | 162 | return 1; /* XXX CCID should dequeue when ready instead of polling */ |
2a91aa39 AB |
163 | } |
164 | ||
165 | static void ccid2_change_l_ack_ratio(struct sock *sk, int val) | |
166 | { | |
167 | struct dccp_sock *dp = dccp_sk(sk); | |
168 | /* | |
169 | * XXX I don't really agree with val != 2. If cwnd is 1, ack ratio | |
170 | * should be 1... it shouldn't be allowed to become 2. | |
171 | * -sorbo. | |
172 | */ | |
173 | if (val != 2) { | |
c0c736db | 174 | const struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
2a91aa39 AB |
175 | int max = hctx->ccid2hctx_cwnd / 2; |
176 | ||
177 | /* round up */ | |
178 | if (hctx->ccid2hctx_cwnd & 1) | |
179 | max++; | |
180 | ||
181 | if (val > max) | |
182 | val = max; | |
183 | } | |
184 | ||
185 | ccid2_pr_debug("changing local ack ratio to %d\n", val); | |
186 | WARN_ON(val <= 0); | |
187 | dp->dccps_l_ack_ratio = val; | |
188 | } | |
189 | ||
190 | static void ccid2_change_cwnd(struct sock *sk, int val) | |
191 | { | |
192 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
193 | ||
194 | if (val == 0) | |
195 | val = 1; | |
196 | ||
197 | /* XXX do we need to change ack ratio? */ | |
198 | ccid2_pr_debug("change cwnd to %d\n", val); | |
199 | ||
200 | BUG_ON(val < 1); | |
201 | hctx->ccid2hctx_cwnd = val; | |
202 | } | |
203 | ||
204 | static void ccid2_start_rto_timer(struct sock *sk); | |
205 | ||
206 | static void ccid2_hc_tx_rto_expire(unsigned long data) | |
207 | { | |
208 | struct sock *sk = (struct sock *)data; | |
209 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
210 | long s; | |
211 | ||
2a91aa39 AB |
212 | bh_lock_sock(sk); |
213 | if (sock_owned_by_user(sk)) { | |
214 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
215 | jiffies + HZ / 5); | |
216 | goto out; | |
217 | } | |
218 | ||
219 | ccid2_pr_debug("RTO_EXPIRE\n"); | |
220 | ||
221 | ccid2_hc_tx_check_sanity(hctx); | |
222 | ||
223 | /* back-off timer */ | |
224 | hctx->ccid2hctx_rto <<= 1; | |
225 | ||
226 | s = hctx->ccid2hctx_rto / HZ; | |
227 | if (s > 60) | |
228 | hctx->ccid2hctx_rto = 60 * HZ; | |
229 | ||
230 | ccid2_start_rto_timer(sk); | |
231 | ||
232 | /* adjust pipe, cwnd etc */ | |
233 | hctx->ccid2hctx_pipe = 0; | |
234 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1; | |
235 | if (hctx->ccid2hctx_ssthresh < 2) | |
236 | hctx->ccid2hctx_ssthresh = 2; | |
237 | ccid2_change_cwnd(sk, 1); | |
238 | ||
239 | /* clear state about stuff we sent */ | |
240 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; | |
241 | hctx->ccid2hctx_ssacks = 0; | |
242 | hctx->ccid2hctx_acks = 0; | |
243 | hctx->ccid2hctx_sent = 0; | |
244 | ||
245 | /* clear ack ratio state. */ | |
246 | hctx->ccid2hctx_arsent = 0; | |
247 | hctx->ccid2hctx_ackloss = 0; | |
248 | hctx->ccid2hctx_rpseq = 0; | |
249 | hctx->ccid2hctx_rpdupack = -1; | |
250 | ccid2_change_l_ack_ratio(sk, 1); | |
251 | ccid2_hc_tx_check_sanity(hctx); | |
252 | out: | |
253 | bh_unlock_sock(sk); | |
77ff72d5 | 254 | sock_put(sk); |
2a91aa39 AB |
255 | } |
256 | ||
257 | static void ccid2_start_rto_timer(struct sock *sk) | |
258 | { | |
259 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
260 | ||
261 | ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto); | |
262 | ||
263 | BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer)); | |
264 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
265 | jiffies + hctx->ccid2hctx_rto); | |
266 | } | |
267 | ||
268 | static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, int len) | |
269 | { | |
270 | struct dccp_sock *dp = dccp_sk(sk); | |
271 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
07978aab | 272 | struct ccid2_seq *next; |
2a91aa39 AB |
273 | u64 seq; |
274 | ||
275 | ccid2_hc_tx_check_sanity(hctx); | |
276 | ||
277 | BUG_ON(!hctx->ccid2hctx_sendwait); | |
278 | hctx->ccid2hctx_sendwait = 0; | |
279 | hctx->ccid2hctx_pipe++; | |
280 | BUG_ON(hctx->ccid2hctx_pipe < 0); | |
281 | ||
282 | /* There is an issue. What if another packet is sent between | |
283 | * packet_send() and packet_sent(). Then the sequence number would be | |
284 | * wrong. | |
285 | * -sorbo. | |
286 | */ | |
287 | seq = dp->dccps_gss; | |
288 | ||
289 | hctx->ccid2hctx_seqh->ccid2s_seq = seq; | |
290 | hctx->ccid2hctx_seqh->ccid2s_acked = 0; | |
291 | hctx->ccid2hctx_seqh->ccid2s_sent = jiffies; | |
2a91aa39 | 292 | |
07978aab AB |
293 | next = hctx->ccid2hctx_seqh->ccid2s_next; |
294 | /* check if we need to alloc more space */ | |
295 | if (next == hctx->ccid2hctx_seqt) { | |
296 | int rc; | |
2a91aa39 | 297 | |
07978aab AB |
298 | ccid2_pr_debug("allocating more space in history\n"); |
299 | rc = ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, GFP_KERNEL); | |
300 | BUG_ON(rc); /* XXX what do we do? */ | |
301 | ||
302 | next = hctx->ccid2hctx_seqh->ccid2s_next; | |
303 | BUG_ON(next == hctx->ccid2hctx_seqt); | |
2a91aa39 | 304 | } |
07978aab AB |
305 | hctx->ccid2hctx_seqh = next; |
306 | ||
307 | ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd, | |
308 | hctx->ccid2hctx_pipe); | |
2a91aa39 AB |
309 | |
310 | hctx->ccid2hctx_sent++; | |
311 | ||
312 | /* Ack Ratio. Need to maintain a concept of how many windows we sent */ | |
313 | hctx->ccid2hctx_arsent++; | |
314 | /* We had an ack loss in this window... */ | |
315 | if (hctx->ccid2hctx_ackloss) { | |
316 | if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) { | |
c0c736db ACM |
317 | hctx->ccid2hctx_arsent = 0; |
318 | hctx->ccid2hctx_ackloss = 0; | |
2a91aa39 | 319 | } |
c0c736db ACM |
320 | } else { |
321 | /* No acks lost up to now... */ | |
2a91aa39 AB |
322 | /* decrease ack ratio if enough packets were sent */ |
323 | if (dp->dccps_l_ack_ratio > 1) { | |
324 | /* XXX don't calculate denominator each time */ | |
c0c736db ACM |
325 | int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio - |
326 | dp->dccps_l_ack_ratio; | |
2a91aa39 | 327 | |
2a91aa39 AB |
328 | denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom; |
329 | ||
330 | if (hctx->ccid2hctx_arsent >= denom) { | |
331 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1); | |
332 | hctx->ccid2hctx_arsent = 0; | |
333 | } | |
c0c736db ACM |
334 | } else { |
335 | /* we can't increase ack ratio further [1] */ | |
2a91aa39 AB |
336 | hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/ |
337 | } | |
338 | } | |
339 | ||
340 | /* setup RTO timer */ | |
c0c736db | 341 | if (!timer_pending(&hctx->ccid2hctx_rtotimer)) |
2a91aa39 | 342 | ccid2_start_rto_timer(sk); |
c0c736db | 343 | |
8d424f6c | 344 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
2a91aa39 AB |
345 | ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe); |
346 | ccid2_pr_debug("Sent: seq=%llu\n", seq); | |
347 | do { | |
348 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqt; | |
349 | ||
350 | while (seqp != hctx->ccid2hctx_seqh) { | |
351 | ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n", | |
352 | seqp->ccid2s_seq, seqp->ccid2s_acked, | |
353 | seqp->ccid2s_sent); | |
354 | seqp = seqp->ccid2s_next; | |
355 | } | |
c0c736db | 356 | } while (0); |
2a91aa39 AB |
357 | ccid2_pr_debug("=========\n"); |
358 | ccid2_hc_tx_check_sanity(hctx); | |
359 | #endif | |
360 | } | |
361 | ||
362 | /* XXX Lame code duplication! | |
363 | * returns -1 if none was found. | |
364 | * else returns the next offset to use in the function call. | |
365 | */ | |
366 | static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset, | |
367 | unsigned char **vec, unsigned char *veclen) | |
368 | { | |
369 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
370 | unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); | |
371 | unsigned char *opt_ptr; | |
372 | const unsigned char *opt_end = (unsigned char *)dh + | |
373 | (dh->dccph_doff * 4); | |
374 | unsigned char opt, len; | |
375 | unsigned char *value; | |
376 | ||
377 | BUG_ON(offset < 0); | |
378 | options += offset; | |
379 | opt_ptr = options; | |
380 | if (opt_ptr >= opt_end) | |
381 | return -1; | |
382 | ||
383 | while (opt_ptr != opt_end) { | |
384 | opt = *opt_ptr++; | |
385 | len = 0; | |
386 | value = NULL; | |
387 | ||
388 | /* Check if this isn't a single byte option */ | |
389 | if (opt > DCCPO_MAX_RESERVED) { | |
390 | if (opt_ptr == opt_end) | |
391 | goto out_invalid_option; | |
392 | ||
393 | len = *opt_ptr++; | |
394 | if (len < 3) | |
395 | goto out_invalid_option; | |
396 | /* | |
397 | * Remove the type and len fields, leaving | |
398 | * just the value size | |
399 | */ | |
400 | len -= 2; | |
401 | value = opt_ptr; | |
402 | opt_ptr += len; | |
403 | ||
404 | if (opt_ptr > opt_end) | |
405 | goto out_invalid_option; | |
406 | } | |
407 | ||
408 | switch (opt) { | |
409 | case DCCPO_ACK_VECTOR_0: | |
410 | case DCCPO_ACK_VECTOR_1: | |
411 | *vec = value; | |
412 | *veclen = len; | |
413 | return offset + (opt_ptr - options); | |
2a91aa39 AB |
414 | } |
415 | } | |
416 | ||
417 | return -1; | |
418 | ||
419 | out_invalid_option: | |
420 | BUG_ON(1); /* should never happen... options were previously parsed ! */ | |
421 | return -1; | |
422 | } | |
423 | ||
77ff72d5 | 424 | static void ccid2_hc_tx_kill_rto_timer(struct sock *sk) |
2a91aa39 | 425 | { |
77ff72d5 AB |
426 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
427 | ||
428 | sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer); | |
429 | ccid2_pr_debug("deleted RTO timer\n"); | |
2a91aa39 AB |
430 | } |
431 | ||
432 | static inline void ccid2_new_ack(struct sock *sk, | |
433 | struct ccid2_seq *seqp, | |
434 | unsigned int *maxincr) | |
435 | { | |
436 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
437 | ||
438 | /* slow start */ | |
439 | if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) { | |
440 | hctx->ccid2hctx_acks = 0; | |
441 | ||
442 | /* We can increase cwnd at most maxincr [ack_ratio/2] */ | |
443 | if (*maxincr) { | |
444 | /* increase every 2 acks */ | |
445 | hctx->ccid2hctx_ssacks++; | |
446 | if (hctx->ccid2hctx_ssacks == 2) { | |
447 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1); | |
448 | hctx->ccid2hctx_ssacks = 0; | |
449 | *maxincr = *maxincr - 1; | |
450 | } | |
c0c736db ACM |
451 | } else { |
452 | /* increased cwnd enough for this single ack */ | |
2a91aa39 AB |
453 | hctx->ccid2hctx_ssacks = 0; |
454 | } | |
c0c736db | 455 | } else { |
2a91aa39 AB |
456 | hctx->ccid2hctx_ssacks = 0; |
457 | hctx->ccid2hctx_acks++; | |
458 | ||
459 | if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) { | |
460 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd + 1); | |
461 | hctx->ccid2hctx_acks = 0; | |
462 | } | |
463 | } | |
464 | ||
465 | /* update RTO */ | |
466 | if (hctx->ccid2hctx_srtt == -1 || | |
29651cda AB |
467 | time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) { |
468 | unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent; | |
2a91aa39 AB |
469 | int s; |
470 | ||
471 | /* first measurement */ | |
472 | if (hctx->ccid2hctx_srtt == -1) { | |
473 | ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n", | |
474 | r, jiffies, seqp->ccid2s_seq); | |
475 | hctx->ccid2hctx_srtt = r; | |
476 | hctx->ccid2hctx_rttvar = r >> 1; | |
c0c736db | 477 | } else { |
2a91aa39 AB |
478 | /* RTTVAR */ |
479 | long tmp = hctx->ccid2hctx_srtt - r; | |
480 | if (tmp < 0) | |
481 | tmp *= -1; | |
482 | ||
483 | tmp >>= 2; | |
484 | hctx->ccid2hctx_rttvar *= 3; | |
485 | hctx->ccid2hctx_rttvar >>= 2; | |
486 | hctx->ccid2hctx_rttvar += tmp; | |
487 | ||
488 | /* SRTT */ | |
489 | hctx->ccid2hctx_srtt *= 7; | |
490 | hctx->ccid2hctx_srtt >>= 3; | |
491 | tmp = r >> 3; | |
492 | hctx->ccid2hctx_srtt += tmp; | |
493 | } | |
494 | s = hctx->ccid2hctx_rttvar << 2; | |
495 | /* clock granularity is 1 when based on jiffies */ | |
496 | if (!s) | |
497 | s = 1; | |
498 | hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s; | |
499 | ||
500 | /* must be at least a second */ | |
501 | s = hctx->ccid2hctx_rto / HZ; | |
502 | /* DCCP doesn't require this [but I like it cuz my code sux] */ | |
503 | #if 1 | |
504 | if (s < 1) | |
505 | hctx->ccid2hctx_rto = HZ; | |
506 | #endif | |
507 | /* max 60 seconds */ | |
508 | if (s > 60) | |
509 | hctx->ccid2hctx_rto = HZ * 60; | |
510 | ||
511 | hctx->ccid2hctx_lastrtt = jiffies; | |
512 | ||
513 | ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n", | |
514 | hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar, | |
515 | hctx->ccid2hctx_rto, HZ, r); | |
516 | hctx->ccid2hctx_sent = 0; | |
517 | } | |
518 | ||
519 | /* we got a new ack, so re-start RTO timer */ | |
77ff72d5 | 520 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
521 | ccid2_start_rto_timer(sk); |
522 | } | |
523 | ||
77ff72d5 | 524 | static void ccid2_hc_tx_dec_pipe(struct sock *sk) |
2a91aa39 | 525 | { |
77ff72d5 AB |
526 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
527 | ||
2a91aa39 AB |
528 | hctx->ccid2hctx_pipe--; |
529 | BUG_ON(hctx->ccid2hctx_pipe < 0); | |
530 | ||
531 | if (hctx->ccid2hctx_pipe == 0) | |
77ff72d5 | 532 | ccid2_hc_tx_kill_rto_timer(sk); |
2a91aa39 AB |
533 | } |
534 | ||
535 | static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
536 | { | |
537 | struct dccp_sock *dp = dccp_sk(sk); | |
538 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
539 | u64 ackno, seqno; | |
540 | struct ccid2_seq *seqp; | |
541 | unsigned char *vector; | |
542 | unsigned char veclen; | |
543 | int offset = 0; | |
544 | int done = 0; | |
545 | int loss = 0; | |
546 | unsigned int maxincr = 0; | |
547 | ||
548 | ccid2_hc_tx_check_sanity(hctx); | |
549 | /* check reverse path congestion */ | |
550 | seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
551 | ||
552 | /* XXX this whole "algorithm" is broken. Need to fix it to keep track | |
553 | * of the seqnos of the dupacks so that rpseq and rpdupack are correct | |
554 | * -sorbo. | |
555 | */ | |
556 | /* need to bootstrap */ | |
557 | if (hctx->ccid2hctx_rpdupack == -1) { | |
558 | hctx->ccid2hctx_rpdupack = 0; | |
559 | hctx->ccid2hctx_rpseq = seqno; | |
c0c736db | 560 | } else { |
2a91aa39 | 561 | /* check if packet is consecutive */ |
c0c736db | 562 | if ((hctx->ccid2hctx_rpseq + 1) == seqno) |
2a91aa39 | 563 | hctx->ccid2hctx_rpseq++; |
2a91aa39 AB |
564 | /* it's a later packet */ |
565 | else if (after48(seqno, hctx->ccid2hctx_rpseq)) { | |
566 | hctx->ccid2hctx_rpdupack++; | |
567 | ||
568 | /* check if we got enough dupacks */ | |
569 | if (hctx->ccid2hctx_rpdupack >= | |
570 | hctx->ccid2hctx_numdupack) { | |
2a91aa39 AB |
571 | hctx->ccid2hctx_rpdupack = -1; /* XXX lame */ |
572 | hctx->ccid2hctx_rpseq = 0; | |
573 | ||
574 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio << 1); | |
575 | } | |
576 | } | |
577 | } | |
578 | ||
579 | /* check forward path congestion */ | |
580 | /* still didn't send out new data packets */ | |
581 | if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) | |
582 | return; | |
583 | ||
584 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
585 | case DCCP_PKT_ACK: | |
586 | case DCCP_PKT_DATAACK: | |
587 | break; | |
2a91aa39 AB |
588 | default: |
589 | return; | |
590 | } | |
591 | ||
592 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
593 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
594 | ||
595 | /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for | |
596 | * this single ack. I round up. | |
597 | * -sorbo. | |
598 | */ | |
599 | maxincr = dp->dccps_l_ack_ratio >> 1; | |
600 | maxincr++; | |
601 | ||
602 | /* go through all ack vectors */ | |
603 | while ((offset = ccid2_ackvector(sk, skb, offset, | |
604 | &vector, &veclen)) != -1) { | |
605 | /* go through this ack vector */ | |
606 | while (veclen--) { | |
607 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
608 | u64 ackno_end_rl; | |
609 | ||
610 | dccp_set_seqno(&ackno_end_rl, ackno - rl); | |
611 | ccid2_pr_debug("ackvec start:%llu end:%llu\n", ackno, | |
612 | ackno_end_rl); | |
613 | /* if the seqno we are analyzing is larger than the | |
614 | * current ackno, then move towards the tail of our | |
615 | * seqnos. | |
616 | */ | |
617 | while (after48(seqp->ccid2s_seq, ackno)) { | |
618 | if (seqp == hctx->ccid2hctx_seqt) { | |
619 | done = 1; | |
620 | break; | |
621 | } | |
622 | seqp = seqp->ccid2s_prev; | |
623 | } | |
624 | if (done) | |
625 | break; | |
626 | ||
627 | /* check all seqnos in the range of the vector | |
628 | * run length | |
629 | */ | |
630 | while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { | |
8e27e465 AB |
631 | const u8 state = *vector & |
632 | DCCP_ACKVEC_STATE_MASK; | |
2a91aa39 AB |
633 | |
634 | /* new packet received or marked */ | |
635 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && | |
636 | !seqp->ccid2s_acked) { | |
637 | if (state == | |
638 | DCCP_ACKVEC_STATE_ECN_MARKED) { | |
639 | loss = 1; | |
c0c736db | 640 | } else |
2a91aa39 AB |
641 | ccid2_new_ack(sk, seqp, |
642 | &maxincr); | |
2a91aa39 AB |
643 | |
644 | seqp->ccid2s_acked = 1; | |
645 | ccid2_pr_debug("Got ack for %llu\n", | |
646 | seqp->ccid2s_seq); | |
77ff72d5 | 647 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 AB |
648 | } |
649 | if (seqp == hctx->ccid2hctx_seqt) { | |
650 | done = 1; | |
651 | break; | |
652 | } | |
653 | seqp = seqp->ccid2s_next; | |
654 | } | |
655 | if (done) | |
656 | break; | |
657 | ||
658 | ||
659 | dccp_set_seqno(&ackno, ackno_end_rl - 1); | |
660 | vector++; | |
661 | } | |
662 | if (done) | |
663 | break; | |
664 | } | |
665 | ||
666 | /* The state about what is acked should be correct now | |
667 | * Check for NUMDUPACK | |
668 | */ | |
669 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
670 | done = 0; | |
671 | while (1) { | |
672 | if (seqp->ccid2s_acked) { | |
673 | done++; | |
c0c736db | 674 | if (done == hctx->ccid2hctx_numdupack) |
2a91aa39 | 675 | break; |
2a91aa39 | 676 | } |
c0c736db | 677 | if (seqp == hctx->ccid2hctx_seqt) |
2a91aa39 | 678 | break; |
2a91aa39 AB |
679 | seqp = seqp->ccid2s_prev; |
680 | } | |
681 | ||
682 | /* If there are at least 3 acknowledgements, anything unacknowledged | |
683 | * below the last sequence number is considered lost | |
684 | */ | |
685 | if (done == hctx->ccid2hctx_numdupack) { | |
686 | struct ccid2_seq *last_acked = seqp; | |
687 | ||
688 | /* check for lost packets */ | |
689 | while (1) { | |
690 | if (!seqp->ccid2s_acked) { | |
691 | loss = 1; | |
77ff72d5 | 692 | ccid2_hc_tx_dec_pipe(sk); |
2a91aa39 AB |
693 | } |
694 | if (seqp == hctx->ccid2hctx_seqt) | |
695 | break; | |
696 | seqp = seqp->ccid2s_prev; | |
697 | } | |
698 | ||
699 | hctx->ccid2hctx_seqt = last_acked; | |
700 | } | |
701 | ||
702 | /* trim acked packets in tail */ | |
703 | while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) { | |
704 | if (!hctx->ccid2hctx_seqt->ccid2s_acked) | |
705 | break; | |
706 | ||
707 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next; | |
708 | } | |
709 | ||
710 | if (loss) { | |
711 | /* XXX do bit shifts guarantee a 0 as the new bit? */ | |
712 | ccid2_change_cwnd(sk, hctx->ccid2hctx_cwnd >> 1); | |
713 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd; | |
714 | if (hctx->ccid2hctx_ssthresh < 2) | |
715 | hctx->ccid2hctx_ssthresh = 2; | |
716 | } | |
717 | ||
718 | ccid2_hc_tx_check_sanity(hctx); | |
719 | } | |
720 | ||
91f0ebf7 | 721 | static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) |
2a91aa39 | 722 | { |
91f0ebf7 | 723 | struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid); |
2a91aa39 | 724 | |
2a91aa39 | 725 | hctx->ccid2hctx_cwnd = 1; |
d458c25c AB |
726 | /* Initialize ssthresh to infinity. This means that we will exit the |
727 | * initial slow-start after the first packet loss. This is what we | |
728 | * want. | |
729 | */ | |
730 | hctx->ccid2hctx_ssthresh = ~0; | |
2a91aa39 | 731 | hctx->ccid2hctx_numdupack = 3; |
07978aab | 732 | hctx->ccid2hctx_seqbufc = 0; |
2a91aa39 AB |
733 | |
734 | /* XXX init ~ to window size... */ | |
07978aab | 735 | if (ccid2_hc_tx_alloc_seq(hctx, CCID2_SEQBUF_LEN, GFP_ATOMIC) != 0) |
2a91aa39 | 736 | return -ENOMEM; |
91f0ebf7 | 737 | |
2a91aa39 AB |
738 | hctx->ccid2hctx_sent = 0; |
739 | hctx->ccid2hctx_rto = 3 * HZ; | |
740 | hctx->ccid2hctx_srtt = -1; | |
741 | hctx->ccid2hctx_rttvar = -1; | |
742 | hctx->ccid2hctx_lastrtt = 0; | |
743 | hctx->ccid2hctx_rpdupack = -1; | |
744 | ||
745 | hctx->ccid2hctx_rtotimer.function = &ccid2_hc_tx_rto_expire; | |
746 | hctx->ccid2hctx_rtotimer.data = (unsigned long)sk; | |
747 | init_timer(&hctx->ccid2hctx_rtotimer); | |
748 | ||
749 | ccid2_hc_tx_check_sanity(hctx); | |
750 | return 0; | |
751 | } | |
752 | ||
753 | static void ccid2_hc_tx_exit(struct sock *sk) | |
754 | { | |
77ff72d5 | 755 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); |
07978aab | 756 | int i; |
2a91aa39 | 757 | |
77ff72d5 | 758 | ccid2_hc_tx_kill_rto_timer(sk); |
07978aab AB |
759 | |
760 | for (i = 0; i < hctx->ccid2hctx_seqbufc; i++) | |
761 | kfree(hctx->ccid2hctx_seqbuf[i]); | |
762 | hctx->ccid2hctx_seqbufc = 0; | |
2a91aa39 AB |
763 | } |
764 | ||
765 | static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
766 | { | |
767 | const struct dccp_sock *dp = dccp_sk(sk); | |
768 | struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk); | |
769 | ||
770 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
771 | case DCCP_PKT_DATA: | |
772 | case DCCP_PKT_DATAACK: | |
773 | hcrx->ccid2hcrx_data++; | |
774 | if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) { | |
775 | dccp_send_ack(sk); | |
776 | hcrx->ccid2hcrx_data = 0; | |
777 | } | |
778 | break; | |
779 | } | |
780 | } | |
781 | ||
91f0ebf7 | 782 | static struct ccid_operations ccid2 = { |
2a91aa39 AB |
783 | .ccid_id = 2, |
784 | .ccid_name = "ccid2", | |
785 | .ccid_owner = THIS_MODULE, | |
91f0ebf7 | 786 | .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), |
2a91aa39 AB |
787 | .ccid_hc_tx_init = ccid2_hc_tx_init, |
788 | .ccid_hc_tx_exit = ccid2_hc_tx_exit, | |
789 | .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, | |
790 | .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, | |
791 | .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, | |
91f0ebf7 | 792 | .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), |
2a91aa39 AB |
793 | .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, |
794 | }; | |
795 | ||
796 | module_param(ccid2_debug, int, 0444); | |
797 | MODULE_PARM_DESC(ccid2_debug, "Enable debug messages"); | |
798 | ||
799 | static __init int ccid2_module_init(void) | |
800 | { | |
801 | return ccid_register(&ccid2); | |
802 | } | |
803 | module_init(ccid2_module_init); | |
804 | ||
805 | static __exit void ccid2_module_exit(void) | |
806 | { | |
807 | ccid_unregister(&ccid2); | |
808 | } | |
809 | module_exit(ccid2_module_exit); | |
810 | ||
811 | MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>"); | |
c0c736db | 812 | MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID"); |
2a91aa39 AB |
813 | MODULE_LICENSE("GPL"); |
814 | MODULE_ALIAS("net-dccp-ccid-2"); |