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afe00251 AB |
1 | /* |
2 | * net/dccp/feat.c | |
3 | * | |
4 | * An implementation of the DCCP protocol | |
5 | * Andrea Bittau <a.bittau@cs.ucl.ac.uk> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the License, or (at your option) any later version. | |
11 | */ | |
12 | ||
13 | #include <linux/config.h> | |
14 | #include <linux/module.h> | |
15 | ||
16 | #include "dccp.h" | |
17 | #include "feat.h" | |
18 | ||
19 | #define DCCP_FEAT_SP_NOAGREE (-123) | |
20 | ||
21 | int dccp_feat_change(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len, | |
22 | gfp_t gfp) | |
23 | { | |
24 | struct dccp_sock *dp = dccp_sk(sk); | |
25 | struct dccp_opt_pend *opt; | |
26 | ||
27 | dccp_pr_debug("feat change type=%d feat=%d\n", type, feature); | |
28 | ||
29 | /* check if that feature is already being negotiated */ | |
30 | list_for_each_entry(opt, &dp->dccps_options.dccpo_pending, | |
31 | dccpop_node) { | |
32 | /* ok we found a negotiation for this option already */ | |
33 | if (opt->dccpop_feat == feature && opt->dccpop_type == type) { | |
34 | dccp_pr_debug("Replacing old\n"); | |
35 | /* replace */ | |
36 | BUG_ON(opt->dccpop_val == NULL); | |
37 | kfree(opt->dccpop_val); | |
38 | opt->dccpop_val = val; | |
39 | opt->dccpop_len = len; | |
40 | opt->dccpop_conf = 0; | |
41 | return 0; | |
42 | } | |
43 | } | |
44 | ||
45 | /* negotiation for a new feature */ | |
46 | opt = kmalloc(sizeof(*opt), gfp); | |
47 | if (opt == NULL) | |
48 | return -ENOMEM; | |
49 | ||
50 | opt->dccpop_type = type; | |
51 | opt->dccpop_feat = feature; | |
52 | opt->dccpop_len = len; | |
53 | opt->dccpop_val = val; | |
54 | opt->dccpop_conf = 0; | |
55 | opt->dccpop_sc = NULL; | |
56 | ||
57 | BUG_ON(opt->dccpop_val == NULL); | |
58 | ||
59 | list_add_tail(&opt->dccpop_node, &dp->dccps_options.dccpo_pending); | |
60 | return 0; | |
61 | } | |
62 | ||
63 | EXPORT_SYMBOL_GPL(dccp_feat_change); | |
64 | ||
65 | /* XXX taking only u8 vals */ | |
66 | static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val) | |
67 | { | |
68 | /* FIXME implement */ | |
69 | dccp_pr_debug("changing [%d] feat %d to %d\n", type, feat, val); | |
70 | return 0; | |
71 | } | |
72 | ||
73 | static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt, | |
74 | u8 *rpref, u8 rlen) | |
75 | { | |
76 | struct dccp_sock *dp = dccp_sk(sk); | |
77 | u8 *spref, slen, *res = NULL; | |
78 | int i, j, rc, agree = 1; | |
79 | ||
80 | BUG_ON(rpref == NULL); | |
81 | ||
82 | /* check if we are the black sheep */ | |
83 | if (dp->dccps_role == DCCP_ROLE_CLIENT) { | |
84 | spref = rpref; | |
85 | slen = rlen; | |
86 | rpref = opt->dccpop_val; | |
87 | rlen = opt->dccpop_len; | |
88 | } else { | |
89 | spref = opt->dccpop_val; | |
90 | slen = opt->dccpop_len; | |
91 | } | |
92 | /* | |
93 | * Now we have server preference list in spref and client preference in | |
94 | * rpref | |
95 | */ | |
96 | BUG_ON(spref == NULL); | |
97 | BUG_ON(rpref == NULL); | |
98 | ||
99 | /* FIXME sanity check vals */ | |
100 | ||
101 | /* Are values in any order? XXX Lame "algorithm" here */ | |
102 | /* XXX assume values are 1 byte */ | |
103 | for (i = 0; i < slen; i++) { | |
104 | for (j = 0; j < rlen; j++) { | |
105 | if (spref[i] == rpref[j]) { | |
106 | res = &spref[i]; | |
107 | break; | |
108 | } | |
109 | } | |
110 | if (res) | |
111 | break; | |
112 | } | |
113 | ||
114 | /* we didn't agree on anything */ | |
115 | if (res == NULL) { | |
116 | /* confirm previous value */ | |
117 | switch (opt->dccpop_feat) { | |
118 | case DCCPF_CCID: | |
119 | /* XXX did i get this right? =P */ | |
120 | if (opt->dccpop_type == DCCPO_CHANGE_L) | |
121 | res = &dp->dccps_options.dccpo_tx_ccid; | |
122 | else | |
123 | res = &dp->dccps_options.dccpo_rx_ccid; | |
124 | break; | |
125 | ||
126 | default: | |
127 | WARN_ON(1); /* XXX implement res */ | |
128 | return -EFAULT; | |
129 | } | |
130 | ||
131 | dccp_pr_debug("Don't agree... reconfirming %d\n", *res); | |
132 | agree = 0; /* this is used for mandatory options... */ | |
133 | } | |
134 | ||
135 | /* need to put result and our preference list */ | |
136 | /* XXX assume 1 byte vals */ | |
137 | rlen = 1 + opt->dccpop_len; | |
138 | rpref = kmalloc(rlen, GFP_ATOMIC); | |
139 | if (rpref == NULL) | |
140 | return -ENOMEM; | |
141 | ||
142 | *rpref = *res; | |
143 | memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len); | |
144 | ||
145 | /* put it in the "confirm queue" */ | |
146 | if (opt->dccpop_sc == NULL) { | |
147 | opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC); | |
148 | if (opt->dccpop_sc == NULL) { | |
149 | kfree(rpref); | |
150 | return -ENOMEM; | |
151 | } | |
152 | } else { | |
153 | /* recycle the confirm slot */ | |
154 | BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); | |
155 | kfree(opt->dccpop_sc->dccpoc_val); | |
156 | dccp_pr_debug("recycling confirm slot\n"); | |
157 | } | |
158 | memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc)); | |
159 | ||
160 | opt->dccpop_sc->dccpoc_val = rpref; | |
161 | opt->dccpop_sc->dccpoc_len = rlen; | |
162 | ||
163 | /* update the option on our side [we are about to send the confirm] */ | |
164 | rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res); | |
165 | if (rc) { | |
166 | kfree(opt->dccpop_sc->dccpoc_val); | |
167 | kfree(opt->dccpop_sc); | |
168 | opt->dccpop_sc = 0; | |
169 | return rc; | |
170 | } | |
171 | ||
172 | dccp_pr_debug("Will confirm %d\n", *rpref); | |
173 | ||
174 | /* say we want to change to X but we just got a confirm X, suppress our | |
175 | * change | |
176 | */ | |
177 | if (!opt->dccpop_conf) { | |
178 | if (*opt->dccpop_val == *res) | |
179 | opt->dccpop_conf = 1; | |
180 | dccp_pr_debug("won't ask for change of same feature\n"); | |
181 | } | |
182 | ||
183 | return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */ | |
184 | } | |
185 | ||
186 | static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) | |
187 | { | |
188 | struct dccp_sock *dp = dccp_sk(sk); | |
189 | struct dccp_opt_pend *opt; | |
190 | int rc = 1; | |
191 | u8 t; | |
192 | ||
193 | /* | |
194 | * We received a CHANGE. We gotta match it against our own preference | |
195 | * list. If we got a CHANGE_R it means it's a change for us, so we need | |
196 | * to compare our CHANGE_L list. | |
197 | */ | |
198 | if (type == DCCPO_CHANGE_L) | |
199 | t = DCCPO_CHANGE_R; | |
200 | else | |
201 | t = DCCPO_CHANGE_L; | |
202 | ||
203 | /* find our preference list for this feature */ | |
204 | list_for_each_entry(opt, &dp->dccps_options.dccpo_pending, | |
205 | dccpop_node) { | |
206 | if (opt->dccpop_type != t || opt->dccpop_feat != feature) | |
207 | continue; | |
208 | ||
209 | /* find the winner from the two preference lists */ | |
210 | rc = dccp_feat_reconcile(sk, opt, val, len); | |
211 | break; | |
212 | } | |
213 | ||
214 | /* We didn't deal with the change. This can happen if we have no | |
215 | * preference list for the feature. In fact, it just shouldn't | |
216 | * happen---if we understand a feature, we should have a preference list | |
217 | * with at least the default value. | |
218 | */ | |
219 | BUG_ON(rc == 1); | |
220 | ||
221 | return rc; | |
222 | } | |
223 | ||
224 | static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) | |
225 | { | |
226 | struct dccp_opt_pend *opt; | |
227 | struct dccp_sock *dp = dccp_sk(sk); | |
228 | u8 *copy; | |
229 | int rc; | |
230 | ||
231 | /* NN features must be change L */ | |
232 | if (type == DCCPO_CHANGE_R) { | |
233 | dccp_pr_debug("received CHANGE_R %d for NN feat %d\n", | |
234 | type, feature); | |
235 | return -EFAULT; | |
236 | } | |
237 | ||
238 | /* XXX sanity check opt val */ | |
239 | ||
240 | /* copy option so we can confirm it */ | |
241 | opt = kzalloc(sizeof(*opt), GFP_ATOMIC); | |
242 | if (opt == NULL) | |
243 | return -ENOMEM; | |
244 | ||
245 | copy = kmalloc(len, GFP_ATOMIC); | |
246 | if (copy == NULL) { | |
247 | kfree(opt); | |
248 | return -ENOMEM; | |
249 | } | |
250 | memcpy(copy, val, len); | |
251 | ||
252 | opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */ | |
253 | opt->dccpop_feat = feature; | |
254 | opt->dccpop_val = copy; | |
255 | opt->dccpop_len = len; | |
256 | ||
257 | /* change feature */ | |
258 | rc = dccp_feat_update(sk, type, feature, *val); | |
259 | if (rc) { | |
260 | kfree(opt->dccpop_val); | |
261 | kfree(opt); | |
262 | return rc; | |
263 | } | |
264 | ||
265 | dccp_pr_debug("Confirming NN feature %d (val=%d)\n", feature, *copy); | |
266 | list_add_tail(&opt->dccpop_node, &dp->dccps_options.dccpo_conf); | |
267 | ||
268 | return 0; | |
269 | } | |
270 | ||
271 | static void dccp_feat_empty_confirm(struct sock *sk, u8 type, u8 feature) | |
272 | { | |
273 | struct dccp_sock *dp = dccp_sk(sk); | |
274 | /* XXX check if other confirms for that are queued and recycle slot */ | |
275 | struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC); | |
276 | ||
277 | if (opt == NULL) { | |
278 | /* XXX what do we do? Ignoring should be fine. It's a change | |
279 | * after all =P | |
280 | */ | |
281 | return; | |
282 | } | |
283 | ||
284 | opt->dccpop_type = type == DCCPO_CHANGE_L ? DCCPO_CONFIRM_R : | |
285 | DCCPO_CONFIRM_L; | |
286 | opt->dccpop_feat = feature; | |
287 | opt->dccpop_val = 0; | |
288 | opt->dccpop_len = 0; | |
289 | ||
290 | /* change feature */ | |
291 | dccp_pr_debug("Empty confirm feature %d type %d\n", feature, type); | |
292 | list_add_tail(&opt->dccpop_node, &dp->dccps_options.dccpo_conf); | |
293 | } | |
294 | ||
295 | static void dccp_feat_flush_confirm(struct sock *sk) | |
296 | { | |
297 | struct dccp_sock *dp = dccp_sk(sk); | |
298 | /* Check if there is anything to confirm in the first place */ | |
299 | int yes = !list_empty(&dp->dccps_options.dccpo_conf); | |
300 | ||
301 | if (!yes) { | |
302 | struct dccp_opt_pend *opt; | |
303 | ||
304 | list_for_each_entry(opt, &dp->dccps_options.dccpo_pending, | |
305 | dccpop_node) { | |
306 | if (opt->dccpop_conf) { | |
307 | yes = 1; | |
308 | break; | |
309 | } | |
310 | } | |
311 | } | |
312 | ||
313 | if (!yes) | |
314 | return; | |
315 | ||
316 | /* OK there is something to confirm... */ | |
317 | /* XXX check if packet is in flight? Send delayed ack?? */ | |
318 | if (sk->sk_state == DCCP_OPEN) | |
319 | dccp_send_ack(sk); | |
320 | } | |
321 | ||
322 | int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) | |
323 | { | |
324 | int rc; | |
325 | ||
326 | dccp_pr_debug("got feat change type=%d feat=%d\n", type, feature); | |
327 | ||
328 | /* figure out if it's SP or NN feature */ | |
329 | switch (feature) { | |
330 | /* deal with SP features */ | |
331 | case DCCPF_CCID: | |
332 | rc = dccp_feat_sp(sk, type, feature, val, len); | |
333 | break; | |
334 | ||
335 | /* deal with NN features */ | |
336 | case DCCPF_ACK_RATIO: | |
337 | rc = dccp_feat_nn(sk, type, feature, val, len); | |
338 | break; | |
339 | ||
340 | /* XXX implement other features */ | |
341 | default: | |
342 | rc = -EFAULT; | |
343 | break; | |
344 | } | |
345 | ||
346 | /* check if there were problems changing features */ | |
347 | if (rc) { | |
348 | /* If we don't agree on SP, we sent a confirm for old value. | |
349 | * However we propagate rc to caller in case option was | |
350 | * mandatory | |
351 | */ | |
352 | if (rc != DCCP_FEAT_SP_NOAGREE) | |
353 | dccp_feat_empty_confirm(sk, type, feature); | |
354 | } | |
355 | ||
356 | /* generate the confirm [if required] */ | |
357 | dccp_feat_flush_confirm(sk); | |
358 | ||
359 | return rc; | |
360 | } | |
361 | ||
362 | EXPORT_SYMBOL_GPL(dccp_feat_change_recv); | |
363 | ||
364 | int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, | |
365 | u8 *val, u8 len) | |
366 | { | |
367 | u8 t; | |
368 | struct dccp_opt_pend *opt; | |
369 | struct dccp_sock *dp = dccp_sk(sk); | |
370 | int rc = 1; | |
371 | int all_confirmed = 1; | |
372 | ||
373 | dccp_pr_debug("got feat confirm type=%d feat=%d\n", type, feature); | |
374 | ||
375 | /* XXX sanity check type & feat */ | |
376 | ||
377 | /* locate our change request */ | |
378 | t = type == DCCPO_CONFIRM_L ? DCCPO_CHANGE_R : DCCPO_CHANGE_L; | |
379 | ||
380 | list_for_each_entry(opt, &dp->dccps_options.dccpo_pending, | |
381 | dccpop_node) { | |
382 | if (!opt->dccpop_conf && opt->dccpop_type == t && | |
383 | opt->dccpop_feat == feature) { | |
384 | /* we found it */ | |
385 | /* XXX do sanity check */ | |
386 | ||
387 | opt->dccpop_conf = 1; | |
388 | ||
389 | /* We got a confirmation---change the option */ | |
390 | dccp_feat_update(sk, opt->dccpop_type, | |
391 | opt->dccpop_feat, *val); | |
392 | ||
393 | dccp_pr_debug("feat %d type %d confirmed %d\n", | |
394 | feature, type, *val); | |
395 | rc = 0; | |
396 | break; | |
397 | } | |
398 | ||
399 | if (!opt->dccpop_conf) | |
400 | all_confirmed = 0; | |
401 | } | |
402 | ||
403 | /* fix re-transmit timer */ | |
404 | /* XXX gotta make sure that no option negotiation occurs during | |
405 | * connection shutdown. Consider that the CLOSEREQ is sent and timer is | |
406 | * on. if all options are confirmed it might kill timer which should | |
407 | * remain alive until close is received. | |
408 | */ | |
409 | if (all_confirmed) { | |
410 | dccp_pr_debug("clear feat negotiation timer %p\n", sk); | |
411 | inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); | |
412 | } | |
413 | ||
414 | if (rc) | |
415 | dccp_pr_debug("feat %d type %d never requested\n", | |
416 | feature, type); | |
417 | return 0; | |
418 | } | |
419 | ||
420 | EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv); | |
421 | ||
422 | void dccp_feat_clean(struct sock *sk) | |
423 | { | |
424 | struct dccp_sock *dp = dccp_sk(sk); | |
425 | struct dccp_opt_pend *opt, *next; | |
426 | ||
427 | list_for_each_entry_safe(opt, next, &dp->dccps_options.dccpo_pending, | |
428 | dccpop_node) { | |
429 | BUG_ON(opt->dccpop_val == NULL); | |
430 | kfree(opt->dccpop_val); | |
431 | ||
432 | if (opt->dccpop_sc != NULL) { | |
433 | BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); | |
434 | kfree(opt->dccpop_sc->dccpoc_val); | |
435 | kfree(opt->dccpop_sc); | |
436 | } | |
437 | ||
438 | kfree(opt); | |
439 | } | |
440 | INIT_LIST_HEAD(&dp->dccps_options.dccpo_pending); | |
441 | ||
442 | list_for_each_entry_safe(opt, next, &dp->dccps_options.dccpo_conf, | |
443 | dccpop_node) { | |
444 | BUG_ON(opt == NULL); | |
445 | if (opt->dccpop_val != NULL) | |
446 | kfree(opt->dccpop_val); | |
447 | kfree(opt); | |
448 | } | |
449 | INIT_LIST_HEAD(&dp->dccps_options.dccpo_conf); | |
450 | } | |
451 | ||
452 | EXPORT_SYMBOL_GPL(dccp_feat_clean); | |
453 | ||
454 | /* this is to be called only when a listening sock creates its child. It is | |
455 | * assumed by the function---the confirm is not duplicated, but rather it is | |
456 | * "passed on". | |
457 | */ | |
458 | int dccp_feat_clone(struct sock *oldsk, struct sock *newsk) | |
459 | { | |
460 | struct dccp_sock *olddp = dccp_sk(oldsk); | |
461 | struct dccp_sock *newdp = dccp_sk(newsk); | |
462 | struct dccp_opt_pend *opt; | |
463 | int rc = 0; | |
464 | ||
465 | INIT_LIST_HEAD(&newdp->dccps_options.dccpo_pending); | |
466 | INIT_LIST_HEAD(&newdp->dccps_options.dccpo_conf); | |
467 | ||
468 | list_for_each_entry(opt, &olddp->dccps_options.dccpo_pending, | |
469 | dccpop_node) { | |
470 | struct dccp_opt_pend *newopt; | |
471 | /* copy the value of the option */ | |
472 | u8 *val = kmalloc(opt->dccpop_len, GFP_ATOMIC); | |
473 | ||
474 | if (val == NULL) | |
475 | goto out_clean; | |
476 | memcpy(val, opt->dccpop_val, opt->dccpop_len); | |
477 | ||
478 | newopt = kmalloc(sizeof(*newopt), GFP_ATOMIC); | |
479 | if (newopt == NULL) { | |
480 | kfree(val); | |
481 | goto out_clean; | |
482 | } | |
483 | ||
484 | /* insert the option */ | |
485 | memcpy(newopt, opt, sizeof(*newopt)); | |
486 | newopt->dccpop_val = val; | |
487 | list_add_tail(&newopt->dccpop_node, | |
488 | &newdp->dccps_options.dccpo_pending); | |
489 | ||
490 | /* XXX what happens with backlogs and multiple connections at | |
491 | * once... | |
492 | */ | |
493 | /* the master socket no longer needs to worry about confirms */ | |
494 | opt->dccpop_sc = 0; /* it's not a memleak---new socket has it */ | |
495 | ||
496 | /* reset state for a new socket */ | |
497 | opt->dccpop_conf = 0; | |
498 | } | |
499 | ||
500 | /* XXX not doing anything about the conf queue */ | |
501 | ||
502 | out: | |
503 | return rc; | |
504 | ||
505 | out_clean: | |
506 | dccp_feat_clean(newsk); | |
507 | rc = -ENOMEM; | |
508 | goto out; | |
509 | } | |
510 | ||
511 | EXPORT_SYMBOL_GPL(dccp_feat_clone); | |
512 | ||
513 | static int __dccp_feat_init(struct sock *sk, u8 type, u8 feat, u8 *val, u8 len) | |
514 | { | |
515 | int rc = -ENOMEM; | |
516 | u8 *copy = kmalloc(len, GFP_KERNEL); | |
517 | ||
518 | if (copy != NULL) { | |
519 | memcpy(copy, val, len); | |
520 | rc = dccp_feat_change(sk, type, feat, copy, len, GFP_KERNEL); | |
521 | if (rc) | |
522 | kfree(copy); | |
523 | } | |
524 | return rc; | |
525 | } | |
526 | ||
527 | int dccp_feat_init(struct sock *sk) | |
528 | { | |
529 | struct dccp_sock *dp = dccp_sk(sk); | |
530 | int rc; | |
531 | ||
532 | INIT_LIST_HEAD(&dp->dccps_options.dccpo_pending); | |
533 | INIT_LIST_HEAD(&dp->dccps_options.dccpo_conf); | |
534 | ||
535 | /* CCID L */ | |
536 | rc = __dccp_feat_init(sk, DCCPO_CHANGE_L, DCCPF_CCID, | |
537 | &dp->dccps_options.dccpo_tx_ccid, 1); | |
538 | if (rc) | |
539 | goto out; | |
540 | ||
541 | /* CCID R */ | |
542 | rc = __dccp_feat_init(sk, DCCPO_CHANGE_R, DCCPF_CCID, | |
543 | &dp->dccps_options.dccpo_rx_ccid, 1); | |
544 | if (rc) | |
545 | goto out; | |
546 | ||
547 | /* Ack ratio */ | |
548 | rc = __dccp_feat_init(sk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO, | |
549 | &dp->dccps_options.dccpo_ack_ratio, 1); | |
550 | out: | |
551 | return rc; | |
552 | } | |
553 | ||
554 | EXPORT_SYMBOL_GPL(dccp_feat_init); |