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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 RFC 4341 | |
27 | */ | |
28 | ||
29 | #include "../ccid.h" | |
30 | #include "../dccp.h" | |
31 | #include "ccid2.h" | |
32 | ||
33 | ||
34 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG | |
35 | static int ccid2_debug; | |
36 | #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a) | |
37 | ||
38 | static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx) | |
39 | { | |
40 | int len = 0; | |
41 | int pipe = 0; | |
42 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqh; | |
43 | ||
44 | /* there is data in the chain */ | |
45 | if (seqp != hctx->ccid2hctx_seqt) { | |
46 | seqp = seqp->ccid2s_prev; | |
47 | len++; | |
48 | if (!seqp->ccid2s_acked) | |
49 | pipe++; | |
50 | ||
51 | while (seqp != hctx->ccid2hctx_seqt) { | |
52 | struct ccid2_seq *prev = seqp->ccid2s_prev; | |
53 | ||
54 | len++; | |
55 | if (!prev->ccid2s_acked) | |
56 | pipe++; | |
57 | ||
58 | /* packets are sent sequentially */ | |
59 | BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq, | |
60 | prev->ccid2s_seq ) >= 0); | |
61 | BUG_ON(time_before(seqp->ccid2s_sent, | |
62 | prev->ccid2s_sent)); | |
63 | ||
64 | seqp = prev; | |
65 | } | |
66 | } | |
67 | ||
68 | BUG_ON(pipe != hctx->ccid2hctx_pipe); | |
69 | ccid2_pr_debug("len of chain=%d\n", len); | |
70 | ||
71 | do { | |
72 | seqp = seqp->ccid2s_prev; | |
73 | len++; | |
74 | } while (seqp != hctx->ccid2hctx_seqh); | |
75 | ||
76 | ccid2_pr_debug("total len=%d\n", len); | |
77 | BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN); | |
78 | } | |
79 | #else | |
80 | #define ccid2_pr_debug(format, a...) | |
81 | #define ccid2_hc_tx_check_sanity(hctx) | |
82 | #endif | |
83 | ||
84 | static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx) | |
85 | { | |
86 | struct ccid2_seq *seqp; | |
87 | int i; | |
88 | ||
89 | /* check if we have space to preserve the pointer to the buffer */ | |
90 | if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) / | |
91 | sizeof(struct ccid2_seq*))) | |
92 | return -ENOMEM; | |
93 | ||
94 | /* allocate buffer and initialize linked list */ | |
95 | seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any()); | |
96 | if (seqp == NULL) | |
97 | return -ENOMEM; | |
98 | ||
99 | for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) { | |
100 | seqp[i].ccid2s_next = &seqp[i + 1]; | |
101 | seqp[i + 1].ccid2s_prev = &seqp[i]; | |
102 | } | |
103 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp; | |
104 | seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; | |
105 | ||
106 | /* This is the first allocation. Initiate the head and tail. */ | |
107 | if (hctx->ccid2hctx_seqbufc == 0) | |
108 | hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp; | |
109 | else { | |
110 | /* link the existing list with the one we just created */ | |
111 | hctx->ccid2hctx_seqh->ccid2s_next = seqp; | |
112 | seqp->ccid2s_prev = hctx->ccid2hctx_seqh; | |
113 | ||
114 | hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; | |
115 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->ccid2hctx_seqt; | |
116 | } | |
117 | ||
118 | /* store the original pointer to the buffer so we can free it */ | |
119 | hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp; | |
120 | hctx->ccid2hctx_seqbufc++; | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) | |
126 | { | |
127 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
128 | ||
129 | ccid2_pr_debug("pipe=%d cwnd=%d\n", hctx->ccid2hctx_pipe, | |
130 | hctx->ccid2hctx_cwnd); | |
131 | ||
132 | if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd) { | |
133 | /* OK we can send... make sure previous packet was sent off */ | |
134 | if (!hctx->ccid2hctx_sendwait) { | |
135 | hctx->ccid2hctx_sendwait = 1; | |
136 | return 0; | |
137 | } | |
138 | } | |
139 | ||
140 | return 1; /* XXX CCID should dequeue when ready instead of polling */ | |
141 | } | |
142 | ||
143 | static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) | |
144 | { | |
145 | struct dccp_sock *dp = dccp_sk(sk); | |
146 | u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->ccid2hctx_cwnd, 2); | |
147 | ||
148 | /* | |
149 | * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from | |
150 | * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always | |
151 | * acceptable since this causes starvation/deadlock whenever cwnd < 2. | |
152 | * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled). | |
153 | */ | |
154 | if (val == 0 || val > max_ratio) { | |
155 | DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio); | |
156 | val = max_ratio; | |
157 | } | |
158 | if (val > 0xFFFF) /* RFC 4340, 11.3 */ | |
159 | val = 0xFFFF; | |
160 | ||
161 | if (val == dp->dccps_l_ack_ratio) | |
162 | return; | |
163 | ||
164 | ccid2_pr_debug("changing local ack ratio to %u\n", val); | |
165 | dp->dccps_l_ack_ratio = val; | |
166 | } | |
167 | ||
168 | static void ccid2_change_cwnd(struct ccid2_hc_tx_sock *hctx, u32 val) | |
169 | { | |
170 | hctx->ccid2hctx_cwnd = val? : 1; | |
171 | ccid2_pr_debug("changed cwnd to %u\n", hctx->ccid2hctx_cwnd); | |
172 | } | |
173 | ||
174 | static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val) | |
175 | { | |
176 | ccid2_pr_debug("change SRTT to %ld\n", val); | |
177 | hctx->ccid2hctx_srtt = val; | |
178 | } | |
179 | ||
180 | static void ccid2_change_pipe(struct ccid2_hc_tx_sock *hctx, long val) | |
181 | { | |
182 | hctx->ccid2hctx_pipe = val; | |
183 | } | |
184 | ||
185 | static void ccid2_start_rto_timer(struct sock *sk); | |
186 | ||
187 | static void ccid2_hc_tx_rto_expire(unsigned long data) | |
188 | { | |
189 | struct sock *sk = (struct sock *)data; | |
190 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
191 | long s; | |
192 | ||
193 | bh_lock_sock(sk); | |
194 | if (sock_owned_by_user(sk)) { | |
195 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
196 | jiffies + HZ / 5); | |
197 | goto out; | |
198 | } | |
199 | ||
200 | ccid2_pr_debug("RTO_EXPIRE\n"); | |
201 | ||
202 | ccid2_hc_tx_check_sanity(hctx); | |
203 | ||
204 | /* back-off timer */ | |
205 | hctx->ccid2hctx_rto <<= 1; | |
206 | ||
207 | s = hctx->ccid2hctx_rto / HZ; | |
208 | if (s > 60) | |
209 | hctx->ccid2hctx_rto = 60 * HZ; | |
210 | ||
211 | ccid2_start_rto_timer(sk); | |
212 | ||
213 | /* adjust pipe, cwnd etc */ | |
214 | ccid2_change_pipe(hctx, 0); | |
215 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd >> 1; | |
216 | if (hctx->ccid2hctx_ssthresh < 2) | |
217 | hctx->ccid2hctx_ssthresh = 2; | |
218 | ccid2_change_cwnd(hctx, 1); | |
219 | ||
220 | /* clear state about stuff we sent */ | |
221 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh; | |
222 | hctx->ccid2hctx_ssacks = 0; | |
223 | hctx->ccid2hctx_acks = 0; | |
224 | hctx->ccid2hctx_sent = 0; | |
225 | ||
226 | /* clear ack ratio state. */ | |
227 | hctx->ccid2hctx_rpseq = 0; | |
228 | hctx->ccid2hctx_rpdupack = -1; | |
229 | ccid2_change_l_ack_ratio(sk, 1); | |
230 | ccid2_hc_tx_check_sanity(hctx); | |
231 | out: | |
232 | bh_unlock_sock(sk); | |
233 | sock_put(sk); | |
234 | } | |
235 | ||
236 | static void ccid2_start_rto_timer(struct sock *sk) | |
237 | { | |
238 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
239 | ||
240 | ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto); | |
241 | ||
242 | BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer)); | |
243 | sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer, | |
244 | jiffies + hctx->ccid2hctx_rto); | |
245 | } | |
246 | ||
247 | static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) | |
248 | { | |
249 | struct dccp_sock *dp = dccp_sk(sk); | |
250 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
251 | struct ccid2_seq *next; | |
252 | u64 seq; | |
253 | ||
254 | ccid2_hc_tx_check_sanity(hctx); | |
255 | ||
256 | BUG_ON(!hctx->ccid2hctx_sendwait); | |
257 | hctx->ccid2hctx_sendwait = 0; | |
258 | ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe + 1); | |
259 | BUG_ON(hctx->ccid2hctx_pipe < 0); | |
260 | ||
261 | /* There is an issue. What if another packet is sent between | |
262 | * packet_send() and packet_sent(). Then the sequence number would be | |
263 | * wrong. | |
264 | * -sorbo. | |
265 | */ | |
266 | seq = dp->dccps_gss; | |
267 | ||
268 | hctx->ccid2hctx_seqh->ccid2s_seq = seq; | |
269 | hctx->ccid2hctx_seqh->ccid2s_acked = 0; | |
270 | hctx->ccid2hctx_seqh->ccid2s_sent = jiffies; | |
271 | ||
272 | next = hctx->ccid2hctx_seqh->ccid2s_next; | |
273 | /* check if we need to alloc more space */ | |
274 | if (next == hctx->ccid2hctx_seqt) { | |
275 | if (ccid2_hc_tx_alloc_seq(hctx)) { | |
276 | DCCP_CRIT("packet history - out of memory!"); | |
277 | /* FIXME: find a more graceful way to bail out */ | |
278 | return; | |
279 | } | |
280 | next = hctx->ccid2hctx_seqh->ccid2s_next; | |
281 | BUG_ON(next == hctx->ccid2hctx_seqt); | |
282 | } | |
283 | hctx->ccid2hctx_seqh = next; | |
284 | ||
285 | ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd, | |
286 | hctx->ccid2hctx_pipe); | |
287 | ||
288 | hctx->ccid2hctx_sent++; | |
289 | ||
290 | /* | |
291 | * FIXME: The code below is broken and the variables have been removed | |
292 | * from the socket struct. The `ackloss' variable was always set to 0, | |
293 | * and with arsent there are several problems: | |
294 | * (i) it doesn't just count the number of Acks, but all sent packets; | |
295 | * (ii) it is expressed in # of packets, not # of windows, so the | |
296 | * comparison below uses the wrong formula: Appendix A of RFC 4341 | |
297 | * comes up with the number K = cwnd / (R^2 - R) of consecutive windows | |
298 | * of data with no lost or marked Ack packets. If arsent were the # of | |
299 | * consecutive Acks received without loss, then Ack Ratio needs to be | |
300 | * decreased by 1 when | |
301 | * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2) | |
302 | * where cwnd / R is the number of Acks received per window of data | |
303 | * (cf. RFC 4341, App. A). The problems are that | |
304 | * - arsent counts other packets as well; | |
305 | * - the comparison uses a formula different from RFC 4341; | |
306 | * - computing a cubic/quadratic equation each time is too complicated. | |
307 | * Hence a different algorithm is needed. | |
308 | */ | |
309 | #if 0 | |
310 | /* Ack Ratio. Need to maintain a concept of how many windows we sent */ | |
311 | hctx->ccid2hctx_arsent++; | |
312 | /* We had an ack loss in this window... */ | |
313 | if (hctx->ccid2hctx_ackloss) { | |
314 | if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) { | |
315 | hctx->ccid2hctx_arsent = 0; | |
316 | hctx->ccid2hctx_ackloss = 0; | |
317 | } | |
318 | } else { | |
319 | /* No acks lost up to now... */ | |
320 | /* decrease ack ratio if enough packets were sent */ | |
321 | if (dp->dccps_l_ack_ratio > 1) { | |
322 | /* XXX don't calculate denominator each time */ | |
323 | int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio - | |
324 | dp->dccps_l_ack_ratio; | |
325 | ||
326 | denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom; | |
327 | ||
328 | if (hctx->ccid2hctx_arsent >= denom) { | |
329 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1); | |
330 | hctx->ccid2hctx_arsent = 0; | |
331 | } | |
332 | } else { | |
333 | /* we can't increase ack ratio further [1] */ | |
334 | hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/ | |
335 | } | |
336 | } | |
337 | #endif | |
338 | ||
339 | /* setup RTO timer */ | |
340 | if (!timer_pending(&hctx->ccid2hctx_rtotimer)) | |
341 | ccid2_start_rto_timer(sk); | |
342 | ||
343 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG | |
344 | ccid2_pr_debug("pipe=%d\n", hctx->ccid2hctx_pipe); | |
345 | ccid2_pr_debug("Sent: seq=%llu\n", (unsigned long long)seq); | |
346 | do { | |
347 | struct ccid2_seq *seqp = hctx->ccid2hctx_seqt; | |
348 | ||
349 | while (seqp != hctx->ccid2hctx_seqh) { | |
350 | ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n", | |
351 | (unsigned long long)seqp->ccid2s_seq, | |
352 | seqp->ccid2s_acked, seqp->ccid2s_sent); | |
353 | seqp = seqp->ccid2s_next; | |
354 | } | |
355 | } while (0); | |
356 | ccid2_pr_debug("=========\n"); | |
357 | ccid2_hc_tx_check_sanity(hctx); | |
358 | #endif | |
359 | } | |
360 | ||
361 | /* XXX Lame code duplication! | |
362 | * returns -1 if none was found. | |
363 | * else returns the next offset to use in the function call. | |
364 | */ | |
365 | static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset, | |
366 | unsigned char **vec, unsigned char *veclen) | |
367 | { | |
368 | const struct dccp_hdr *dh = dccp_hdr(skb); | |
369 | unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); | |
370 | unsigned char *opt_ptr; | |
371 | const unsigned char *opt_end = (unsigned char *)dh + | |
372 | (dh->dccph_doff * 4); | |
373 | unsigned char opt, len; | |
374 | unsigned char *value; | |
375 | ||
376 | BUG_ON(offset < 0); | |
377 | options += offset; | |
378 | opt_ptr = options; | |
379 | if (opt_ptr >= opt_end) | |
380 | return -1; | |
381 | ||
382 | while (opt_ptr != opt_end) { | |
383 | opt = *opt_ptr++; | |
384 | len = 0; | |
385 | value = NULL; | |
386 | ||
387 | /* Check if this isn't a single byte option */ | |
388 | if (opt > DCCPO_MAX_RESERVED) { | |
389 | if (opt_ptr == opt_end) | |
390 | goto out_invalid_option; | |
391 | ||
392 | len = *opt_ptr++; | |
393 | if (len < 3) | |
394 | goto out_invalid_option; | |
395 | /* | |
396 | * Remove the type and len fields, leaving | |
397 | * just the value size | |
398 | */ | |
399 | len -= 2; | |
400 | value = opt_ptr; | |
401 | opt_ptr += len; | |
402 | ||
403 | if (opt_ptr > opt_end) | |
404 | goto out_invalid_option; | |
405 | } | |
406 | ||
407 | switch (opt) { | |
408 | case DCCPO_ACK_VECTOR_0: | |
409 | case DCCPO_ACK_VECTOR_1: | |
410 | *vec = value; | |
411 | *veclen = len; | |
412 | return offset + (opt_ptr - options); | |
413 | } | |
414 | } | |
415 | ||
416 | return -1; | |
417 | ||
418 | out_invalid_option: | |
419 | DCCP_BUG("Invalid option - this should not happen (previous parsing)!"); | |
420 | return -1; | |
421 | } | |
422 | ||
423 | static void ccid2_hc_tx_kill_rto_timer(struct sock *sk) | |
424 | { | |
425 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
426 | ||
427 | sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer); | |
428 | ccid2_pr_debug("deleted RTO timer\n"); | |
429 | } | |
430 | ||
431 | static inline void ccid2_new_ack(struct sock *sk, | |
432 | struct ccid2_seq *seqp, | |
433 | unsigned int *maxincr) | |
434 | { | |
435 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
436 | ||
437 | /* slow start */ | |
438 | if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) { | |
439 | hctx->ccid2hctx_acks = 0; | |
440 | ||
441 | /* We can increase cwnd at most maxincr [ack_ratio/2] */ | |
442 | if (*maxincr) { | |
443 | /* increase every 2 acks */ | |
444 | hctx->ccid2hctx_ssacks++; | |
445 | if (hctx->ccid2hctx_ssacks == 2) { | |
446 | ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd+1); | |
447 | hctx->ccid2hctx_ssacks = 0; | |
448 | *maxincr = *maxincr - 1; | |
449 | } | |
450 | } else { | |
451 | /* increased cwnd enough for this single ack */ | |
452 | hctx->ccid2hctx_ssacks = 0; | |
453 | } | |
454 | } else { | |
455 | hctx->ccid2hctx_ssacks = 0; | |
456 | hctx->ccid2hctx_acks++; | |
457 | ||
458 | if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) { | |
459 | ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd + 1); | |
460 | hctx->ccid2hctx_acks = 0; | |
461 | } | |
462 | } | |
463 | ||
464 | /* update RTO */ | |
465 | if (hctx->ccid2hctx_srtt == -1 || | |
466 | time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) { | |
467 | unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent; | |
468 | int s; | |
469 | ||
470 | /* first measurement */ | |
471 | if (hctx->ccid2hctx_srtt == -1) { | |
472 | ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n", | |
473 | r, jiffies, | |
474 | (unsigned long long)seqp->ccid2s_seq); | |
475 | ccid2_change_srtt(hctx, r); | |
476 | hctx->ccid2hctx_rttvar = r >> 1; | |
477 | } else { | |
478 | /* RTTVAR */ | |
479 | long tmp = hctx->ccid2hctx_srtt - r; | |
480 | long srtt; | |
481 | ||
482 | if (tmp < 0) | |
483 | tmp *= -1; | |
484 | ||
485 | tmp >>= 2; | |
486 | hctx->ccid2hctx_rttvar *= 3; | |
487 | hctx->ccid2hctx_rttvar >>= 2; | |
488 | hctx->ccid2hctx_rttvar += tmp; | |
489 | ||
490 | /* SRTT */ | |
491 | srtt = hctx->ccid2hctx_srtt; | |
492 | srtt *= 7; | |
493 | srtt >>= 3; | |
494 | tmp = r >> 3; | |
495 | srtt += tmp; | |
496 | ccid2_change_srtt(hctx, srtt); | |
497 | } | |
498 | s = hctx->ccid2hctx_rttvar << 2; | |
499 | /* clock granularity is 1 when based on jiffies */ | |
500 | if (!s) | |
501 | s = 1; | |
502 | hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s; | |
503 | ||
504 | /* must be at least a second */ | |
505 | s = hctx->ccid2hctx_rto / HZ; | |
506 | /* DCCP doesn't require this [but I like it cuz my code sux] */ | |
507 | #if 1 | |
508 | if (s < 1) | |
509 | hctx->ccid2hctx_rto = HZ; | |
510 | #endif | |
511 | /* max 60 seconds */ | |
512 | if (s > 60) | |
513 | hctx->ccid2hctx_rto = HZ * 60; | |
514 | ||
515 | hctx->ccid2hctx_lastrtt = jiffies; | |
516 | ||
517 | ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n", | |
518 | hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar, | |
519 | hctx->ccid2hctx_rto, HZ, r); | |
520 | hctx->ccid2hctx_sent = 0; | |
521 | } | |
522 | ||
523 | /* we got a new ack, so re-start RTO timer */ | |
524 | ccid2_hc_tx_kill_rto_timer(sk); | |
525 | ccid2_start_rto_timer(sk); | |
526 | } | |
527 | ||
528 | static void ccid2_hc_tx_dec_pipe(struct sock *sk) | |
529 | { | |
530 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
531 | ||
532 | ccid2_change_pipe(hctx, hctx->ccid2hctx_pipe-1); | |
533 | BUG_ON(hctx->ccid2hctx_pipe < 0); | |
534 | ||
535 | if (hctx->ccid2hctx_pipe == 0) | |
536 | ccid2_hc_tx_kill_rto_timer(sk); | |
537 | } | |
538 | ||
539 | static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp) | |
540 | { | |
541 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
542 | ||
543 | if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) { | |
544 | ccid2_pr_debug("Multiple losses in an RTT---treating as one\n"); | |
545 | return; | |
546 | } | |
547 | ||
548 | hctx->ccid2hctx_last_cong = jiffies; | |
549 | ||
550 | ccid2_change_cwnd(hctx, hctx->ccid2hctx_cwnd >> 1); | |
551 | hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd; | |
552 | if (hctx->ccid2hctx_ssthresh < 2) | |
553 | hctx->ccid2hctx_ssthresh = 2; | |
554 | ||
555 | /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */ | |
556 | if (dccp_sk(sk)->dccps_l_ack_ratio > hctx->ccid2hctx_cwnd) | |
557 | ccid2_change_l_ack_ratio(sk, hctx->ccid2hctx_cwnd); | |
558 | } | |
559 | ||
560 | static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
561 | { | |
562 | struct dccp_sock *dp = dccp_sk(sk); | |
563 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
564 | u64 ackno, seqno; | |
565 | struct ccid2_seq *seqp; | |
566 | unsigned char *vector; | |
567 | unsigned char veclen; | |
568 | int offset = 0; | |
569 | int done = 0; | |
570 | unsigned int maxincr = 0; | |
571 | ||
572 | ccid2_hc_tx_check_sanity(hctx); | |
573 | /* check reverse path congestion */ | |
574 | seqno = DCCP_SKB_CB(skb)->dccpd_seq; | |
575 | ||
576 | /* XXX this whole "algorithm" is broken. Need to fix it to keep track | |
577 | * of the seqnos of the dupacks so that rpseq and rpdupack are correct | |
578 | * -sorbo. | |
579 | */ | |
580 | /* need to bootstrap */ | |
581 | if (hctx->ccid2hctx_rpdupack == -1) { | |
582 | hctx->ccid2hctx_rpdupack = 0; | |
583 | hctx->ccid2hctx_rpseq = seqno; | |
584 | } else { | |
585 | /* check if packet is consecutive */ | |
586 | if (dccp_delta_seqno(hctx->ccid2hctx_rpseq, seqno) == 1) | |
587 | hctx->ccid2hctx_rpseq = seqno; | |
588 | /* it's a later packet */ | |
589 | else if (after48(seqno, hctx->ccid2hctx_rpseq)) { | |
590 | hctx->ccid2hctx_rpdupack++; | |
591 | ||
592 | /* check if we got enough dupacks */ | |
593 | if (hctx->ccid2hctx_rpdupack >= | |
594 | hctx->ccid2hctx_numdupack) { | |
595 | hctx->ccid2hctx_rpdupack = -1; /* XXX lame */ | |
596 | hctx->ccid2hctx_rpseq = 0; | |
597 | ||
598 | ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio); | |
599 | } | |
600 | } | |
601 | } | |
602 | ||
603 | /* check forward path congestion */ | |
604 | /* still didn't send out new data packets */ | |
605 | if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt) | |
606 | return; | |
607 | ||
608 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
609 | case DCCP_PKT_ACK: | |
610 | case DCCP_PKT_DATAACK: | |
611 | break; | |
612 | default: | |
613 | return; | |
614 | } | |
615 | ||
616 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; | |
617 | if (after48(ackno, hctx->ccid2hctx_high_ack)) | |
618 | hctx->ccid2hctx_high_ack = ackno; | |
619 | ||
620 | seqp = hctx->ccid2hctx_seqt; | |
621 | while (before48(seqp->ccid2s_seq, ackno)) { | |
622 | seqp = seqp->ccid2s_next; | |
623 | if (seqp == hctx->ccid2hctx_seqh) { | |
624 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
625 | break; | |
626 | } | |
627 | } | |
628 | ||
629 | /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for | |
630 | * this single ack. I round up. | |
631 | * -sorbo. | |
632 | */ | |
633 | maxincr = dp->dccps_l_ack_ratio >> 1; | |
634 | maxincr++; | |
635 | ||
636 | /* go through all ack vectors */ | |
637 | while ((offset = ccid2_ackvector(sk, skb, offset, | |
638 | &vector, &veclen)) != -1) { | |
639 | /* go through this ack vector */ | |
640 | while (veclen--) { | |
641 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; | |
642 | u64 ackno_end_rl = SUB48(ackno, rl); | |
643 | ||
644 | ccid2_pr_debug("ackvec start:%llu end:%llu\n", | |
645 | (unsigned long long)ackno, | |
646 | (unsigned long long)ackno_end_rl); | |
647 | /* if the seqno we are analyzing is larger than the | |
648 | * current ackno, then move towards the tail of our | |
649 | * seqnos. | |
650 | */ | |
651 | while (after48(seqp->ccid2s_seq, ackno)) { | |
652 | if (seqp == hctx->ccid2hctx_seqt) { | |
653 | done = 1; | |
654 | break; | |
655 | } | |
656 | seqp = seqp->ccid2s_prev; | |
657 | } | |
658 | if (done) | |
659 | break; | |
660 | ||
661 | /* check all seqnos in the range of the vector | |
662 | * run length | |
663 | */ | |
664 | while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { | |
665 | const u8 state = *vector & | |
666 | DCCP_ACKVEC_STATE_MASK; | |
667 | ||
668 | /* new packet received or marked */ | |
669 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && | |
670 | !seqp->ccid2s_acked) { | |
671 | if (state == | |
672 | DCCP_ACKVEC_STATE_ECN_MARKED) { | |
673 | ccid2_congestion_event(sk, | |
674 | seqp); | |
675 | } else | |
676 | ccid2_new_ack(sk, seqp, | |
677 | &maxincr); | |
678 | ||
679 | seqp->ccid2s_acked = 1; | |
680 | ccid2_pr_debug("Got ack for %llu\n", | |
681 | (unsigned long long)seqp->ccid2s_seq); | |
682 | ccid2_hc_tx_dec_pipe(sk); | |
683 | } | |
684 | if (seqp == hctx->ccid2hctx_seqt) { | |
685 | done = 1; | |
686 | break; | |
687 | } | |
688 | seqp = seqp->ccid2s_prev; | |
689 | } | |
690 | if (done) | |
691 | break; | |
692 | ||
693 | ackno = SUB48(ackno_end_rl, 1); | |
694 | vector++; | |
695 | } | |
696 | if (done) | |
697 | break; | |
698 | } | |
699 | ||
700 | /* The state about what is acked should be correct now | |
701 | * Check for NUMDUPACK | |
702 | */ | |
703 | seqp = hctx->ccid2hctx_seqt; | |
704 | while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) { | |
705 | seqp = seqp->ccid2s_next; | |
706 | if (seqp == hctx->ccid2hctx_seqh) { | |
707 | seqp = hctx->ccid2hctx_seqh->ccid2s_prev; | |
708 | break; | |
709 | } | |
710 | } | |
711 | done = 0; | |
712 | while (1) { | |
713 | if (seqp->ccid2s_acked) { | |
714 | done++; | |
715 | if (done == hctx->ccid2hctx_numdupack) | |
716 | break; | |
717 | } | |
718 | if (seqp == hctx->ccid2hctx_seqt) | |
719 | break; | |
720 | seqp = seqp->ccid2s_prev; | |
721 | } | |
722 | ||
723 | /* If there are at least 3 acknowledgements, anything unacknowledged | |
724 | * below the last sequence number is considered lost | |
725 | */ | |
726 | if (done == hctx->ccid2hctx_numdupack) { | |
727 | struct ccid2_seq *last_acked = seqp; | |
728 | ||
729 | /* check for lost packets */ | |
730 | while (1) { | |
731 | if (!seqp->ccid2s_acked) { | |
732 | ccid2_pr_debug("Packet lost: %llu\n", | |
733 | (unsigned long long)seqp->ccid2s_seq); | |
734 | /* XXX need to traverse from tail -> head in | |
735 | * order to detect multiple congestion events in | |
736 | * one ack vector. | |
737 | */ | |
738 | ccid2_congestion_event(sk, seqp); | |
739 | ccid2_hc_tx_dec_pipe(sk); | |
740 | } | |
741 | if (seqp == hctx->ccid2hctx_seqt) | |
742 | break; | |
743 | seqp = seqp->ccid2s_prev; | |
744 | } | |
745 | ||
746 | hctx->ccid2hctx_seqt = last_acked; | |
747 | } | |
748 | ||
749 | /* trim acked packets in tail */ | |
750 | while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) { | |
751 | if (!hctx->ccid2hctx_seqt->ccid2s_acked) | |
752 | break; | |
753 | ||
754 | hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next; | |
755 | } | |
756 | ||
757 | ccid2_hc_tx_check_sanity(hctx); | |
758 | } | |
759 | ||
760 | static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) | |
761 | { | |
762 | struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid); | |
763 | struct dccp_sock *dp = dccp_sk(sk); | |
764 | u32 max_ratio; | |
765 | ||
766 | /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */ | |
767 | hctx->ccid2hctx_ssthresh = ~0; | |
768 | hctx->ccid2hctx_numdupack = 3; | |
769 | ||
770 | /* | |
771 | * RFC 4341, 5: "The cwnd parameter is initialized to at most four | |
772 | * packets for new connections, following the rules from [RFC3390]". | |
773 | * We need to convert the bytes of RFC3390 into the packets of RFC 4341. | |
774 | */ | |
775 | hctx->ccid2hctx_cwnd = min(4U, max(2U, 4380U / dp->dccps_mss_cache)); | |
776 | ||
777 | /* Make sure that Ack Ratio is enabled and within bounds. */ | |
778 | max_ratio = DIV_ROUND_UP(hctx->ccid2hctx_cwnd, 2); | |
779 | if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio) | |
780 | dp->dccps_l_ack_ratio = max_ratio; | |
781 | ||
782 | /* XXX init ~ to window size... */ | |
783 | if (ccid2_hc_tx_alloc_seq(hctx)) | |
784 | return -ENOMEM; | |
785 | ||
786 | hctx->ccid2hctx_rto = 3 * HZ; | |
787 | ccid2_change_srtt(hctx, -1); | |
788 | hctx->ccid2hctx_rttvar = -1; | |
789 | hctx->ccid2hctx_rpdupack = -1; | |
790 | hctx->ccid2hctx_last_cong = jiffies; | |
791 | setup_timer(&hctx->ccid2hctx_rtotimer, ccid2_hc_tx_rto_expire, | |
792 | (unsigned long)sk); | |
793 | ||
794 | ccid2_hc_tx_check_sanity(hctx); | |
795 | return 0; | |
796 | } | |
797 | ||
798 | static void ccid2_hc_tx_exit(struct sock *sk) | |
799 | { | |
800 | struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk); | |
801 | int i; | |
802 | ||
803 | ccid2_hc_tx_kill_rto_timer(sk); | |
804 | ||
805 | for (i = 0; i < hctx->ccid2hctx_seqbufc; i++) | |
806 | kfree(hctx->ccid2hctx_seqbuf[i]); | |
807 | hctx->ccid2hctx_seqbufc = 0; | |
808 | } | |
809 | ||
810 | static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) | |
811 | { | |
812 | const struct dccp_sock *dp = dccp_sk(sk); | |
813 | struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk); | |
814 | ||
815 | switch (DCCP_SKB_CB(skb)->dccpd_type) { | |
816 | case DCCP_PKT_DATA: | |
817 | case DCCP_PKT_DATAACK: | |
818 | hcrx->ccid2hcrx_data++; | |
819 | if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) { | |
820 | dccp_send_ack(sk); | |
821 | hcrx->ccid2hcrx_data = 0; | |
822 | } | |
823 | break; | |
824 | } | |
825 | } | |
826 | ||
827 | static struct ccid_operations ccid2 = { | |
828 | .ccid_id = DCCPC_CCID2, | |
829 | .ccid_name = "ccid2", | |
830 | .ccid_owner = THIS_MODULE, | |
831 | .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), | |
832 | .ccid_hc_tx_init = ccid2_hc_tx_init, | |
833 | .ccid_hc_tx_exit = ccid2_hc_tx_exit, | |
834 | .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, | |
835 | .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, | |
836 | .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, | |
837 | .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), | |
838 | .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, | |
839 | }; | |
840 | ||
841 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG | |
842 | module_param(ccid2_debug, bool, 0444); | |
843 | MODULE_PARM_DESC(ccid2_debug, "Enable debug messages"); | |
844 | #endif | |
845 | ||
846 | static __init int ccid2_module_init(void) | |
847 | { | |
848 | return ccid_register(&ccid2); | |
849 | } | |
850 | module_init(ccid2_module_init); | |
851 | ||
852 | static __exit void ccid2_module_exit(void) | |
853 | { | |
854 | ccid_unregister(&ccid2); | |
855 | } | |
856 | module_exit(ccid2_module_exit); | |
857 | ||
858 | MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>"); | |
859 | MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID"); | |
860 | MODULE_LICENSE("GPL"); | |
861 | MODULE_ALIAS("net-dccp-ccid-2"); |