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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 | * ASSUMPTIONS | |
8 | * ----------- | |
9 | * o Feature negotiation is coordinated with connection setup (as in TCP), wild | |
10 | * changes of parameters of an established connection are not supported. | |
11 | * o All currently known SP features have 1-byte quantities. If in the future | |
12 | * extensions of RFCs 4340..42 define features with item lengths larger than | |
13 | * one byte, a feature-specific extension of the code will be required. | |
14 | * | |
15 | * This program is free software; you can redistribute it and/or | |
16 | * modify it under the terms of the GNU General Public License | |
17 | * as published by the Free Software Foundation; either version | |
18 | * 2 of the License, or (at your option) any later version. | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | ||
23 | #include "ccid.h" | |
24 | #include "feat.h" | |
25 | ||
26 | #define DCCP_FEAT_SP_NOAGREE (-123) | |
27 | ||
28 | static const struct { | |
29 | u8 feat_num; /* DCCPF_xxx */ | |
30 | enum dccp_feat_type rxtx; /* RX or TX */ | |
31 | enum dccp_feat_type reconciliation; /* SP or NN */ | |
32 | u8 default_value; /* as in 6.4 */ | |
33 | /* | |
34 | * Lookup table for location and type of features (from RFC 4340/4342) | |
35 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
36 | * | Feature | Location | Reconc. | Initial | Section | | |
37 | * | | RX | TX | SP | NN | Value | Reference | | |
38 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
39 | * | DCCPF_CCID | | X | X | | 2 | 10 | | |
40 | * | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 | | |
41 | * | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 | | |
42 | * | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 | | |
43 | * | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 | | |
44 | * | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 | | |
45 | * | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 | | |
46 | * | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 | | |
47 | * | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 | | |
48 | * | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 | | |
49 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
50 | */ | |
51 | } dccp_feat_table[] = { | |
52 | { DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2 }, | |
53 | { DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0 }, | |
54 | { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100 }, | |
55 | { DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0 }, | |
56 | { DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2 }, | |
57 | { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0 }, | |
58 | { DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0 }, | |
59 | { DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0 }, | |
60 | { DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0 }, | |
61 | { DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0 }, | |
62 | }; | |
63 | #define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table) | |
64 | ||
65 | /** | |
66 | * dccp_feat_index - Hash function to map feature number into array position | |
67 | * Returns consecutive array index or -1 if the feature is not understood. | |
68 | */ | |
69 | static int dccp_feat_index(u8 feat_num) | |
70 | { | |
71 | /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */ | |
72 | if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM) | |
73 | return feat_num - 1; | |
74 | ||
75 | /* | |
76 | * Other features: add cases for new feature types here after adding | |
77 | * them to the above table. | |
78 | */ | |
79 | switch (feat_num) { | |
80 | case DCCPF_SEND_LEV_RATE: | |
81 | return DCCP_FEAT_SUPPORTED_MAX - 1; | |
82 | } | |
83 | return -1; | |
84 | } | |
85 | ||
86 | static u8 dccp_feat_type(u8 feat_num) | |
87 | { | |
88 | int idx = dccp_feat_index(feat_num); | |
89 | ||
90 | if (idx < 0) | |
91 | return FEAT_UNKNOWN; | |
92 | return dccp_feat_table[idx].reconciliation; | |
93 | } | |
94 | ||
95 | static int dccp_feat_default_value(u8 feat_num) | |
96 | { | |
97 | int idx = dccp_feat_index(feat_num); | |
98 | /* | |
99 | * There are no default values for unknown features, so encountering a | |
100 | * negative index here indicates a serious problem somewhere else. | |
101 | */ | |
102 | DCCP_BUG_ON(idx < 0); | |
103 | ||
104 | return idx < 0 ? 0 : dccp_feat_table[idx].default_value; | |
105 | } | |
106 | ||
107 | /* copy constructor, fval must not already contain allocated memory */ | |
108 | static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len) | |
109 | { | |
110 | fval->sp.len = len; | |
111 | if (fval->sp.len > 0) { | |
112 | fval->sp.vec = kmemdup(val, len, gfp_any()); | |
113 | if (fval->sp.vec == NULL) { | |
114 | fval->sp.len = 0; | |
115 | return -ENOBUFS; | |
116 | } | |
117 | } | |
118 | return 0; | |
119 | } | |
120 | ||
121 | static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val) | |
122 | { | |
123 | if (unlikely(val == NULL)) | |
124 | return; | |
125 | if (dccp_feat_type(feat_num) == FEAT_SP) | |
126 | kfree(val->sp.vec); | |
127 | memset(val, 0, sizeof(*val)); | |
128 | } | |
129 | ||
130 | static struct dccp_feat_entry * | |
131 | dccp_feat_clone_entry(struct dccp_feat_entry const *original) | |
132 | { | |
133 | struct dccp_feat_entry *new; | |
134 | u8 type = dccp_feat_type(original->feat_num); | |
135 | ||
136 | if (type == FEAT_UNKNOWN) | |
137 | return NULL; | |
138 | ||
139 | new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any()); | |
140 | if (new == NULL) | |
141 | return NULL; | |
142 | ||
143 | if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val, | |
144 | original->val.sp.vec, | |
145 | original->val.sp.len)) { | |
146 | kfree(new); | |
147 | return NULL; | |
148 | } | |
149 | return new; | |
150 | } | |
151 | ||
152 | static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry) | |
153 | { | |
154 | if (entry != NULL) { | |
155 | dccp_feat_val_destructor(entry->feat_num, &entry->val); | |
156 | kfree(entry); | |
157 | } | |
158 | } | |
159 | ||
160 | /* | |
161 | * List management functions | |
162 | * | |
163 | * Feature negotiation lists rely on and maintain the following invariants: | |
164 | * - each feat_num in the list is known, i.e. we know its type and default value | |
165 | * - each feat_num/is_local combination is unique (old entries are overwritten) | |
166 | * - SP values are always freshly allocated | |
167 | * - list is sorted in increasing order of feature number (faster lookup) | |
168 | */ | |
169 | ||
170 | /** | |
171 | * dccp_feat_entry_new - Central list update routine (called by all others) | |
172 | * @head: list to add to | |
173 | * @feat: feature number | |
174 | * @local: whether the local (1) or remote feature with number @feat is meant | |
175 | * This is the only constructor and serves to ensure the above invariants. | |
176 | */ | |
177 | static struct dccp_feat_entry * | |
178 | dccp_feat_entry_new(struct list_head *head, u8 feat, bool local) | |
179 | { | |
180 | struct dccp_feat_entry *entry; | |
181 | ||
182 | list_for_each_entry(entry, head, node) | |
183 | if (entry->feat_num == feat && entry->is_local == local) { | |
184 | dccp_feat_val_destructor(entry->feat_num, &entry->val); | |
185 | return entry; | |
186 | } else if (entry->feat_num > feat) { | |
187 | head = &entry->node; | |
188 | break; | |
189 | } | |
190 | ||
191 | entry = kmalloc(sizeof(*entry), gfp_any()); | |
192 | if (entry != NULL) { | |
193 | entry->feat_num = feat; | |
194 | entry->is_local = local; | |
195 | list_add_tail(&entry->node, head); | |
196 | } | |
197 | return entry; | |
198 | } | |
199 | ||
200 | /** | |
201 | * dccp_feat_push_change - Add/overwrite a Change option in the list | |
202 | * @fn_list: feature-negotiation list to update | |
203 | * @feat: one of %dccp_feature_numbers | |
204 | * @local: whether local (1) or remote (0) @feat_num is meant | |
205 | * @needs_mandatory: whether to use Mandatory feature negotiation options | |
206 | * @fval: pointer to NN/SP value to be inserted (will be copied) | |
207 | */ | |
208 | static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local, | |
209 | u8 mandatory, dccp_feat_val *fval) | |
210 | { | |
211 | struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); | |
212 | ||
213 | if (new == NULL) | |
214 | return -ENOMEM; | |
215 | ||
216 | new->feat_num = feat; | |
217 | new->is_local = local; | |
218 | new->state = FEAT_INITIALISING; | |
219 | new->needs_confirm = 0; | |
220 | new->empty_confirm = 0; | |
221 | new->val = *fval; | |
222 | new->needs_mandatory = mandatory; | |
223 | ||
224 | return 0; | |
225 | } | |
226 | ||
227 | static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry) | |
228 | { | |
229 | list_del(&entry->node); | |
230 | dccp_feat_entry_destructor(entry); | |
231 | } | |
232 | ||
233 | void dccp_feat_list_purge(struct list_head *fn_list) | |
234 | { | |
235 | struct dccp_feat_entry *entry, *next; | |
236 | ||
237 | list_for_each_entry_safe(entry, next, fn_list, node) | |
238 | dccp_feat_entry_destructor(entry); | |
239 | INIT_LIST_HEAD(fn_list); | |
240 | } | |
241 | EXPORT_SYMBOL_GPL(dccp_feat_list_purge); | |
242 | ||
243 | /* generate @to as full clone of @from - @to must not contain any nodes */ | |
244 | int dccp_feat_clone_list(struct list_head const *from, struct list_head *to) | |
245 | { | |
246 | struct dccp_feat_entry *entry, *new; | |
247 | ||
248 | INIT_LIST_HEAD(to); | |
249 | list_for_each_entry(entry, from, node) { | |
250 | new = dccp_feat_clone_entry(entry); | |
251 | if (new == NULL) | |
252 | goto cloning_failed; | |
253 | list_add_tail(&new->node, to); | |
254 | } | |
255 | return 0; | |
256 | ||
257 | cloning_failed: | |
258 | dccp_feat_list_purge(to); | |
259 | return -ENOMEM; | |
260 | } | |
261 | ||
262 | static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val) | |
263 | { | |
264 | switch (feat_num) { | |
265 | case DCCPF_ACK_RATIO: | |
266 | return val <= DCCPF_ACK_RATIO_MAX; | |
267 | case DCCPF_SEQUENCE_WINDOW: | |
268 | return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX; | |
269 | } | |
270 | return 0; /* feature unknown - so we can't tell */ | |
271 | } | |
272 | ||
273 | /* check that SP values are within the ranges defined in RFC 4340 */ | |
274 | static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val) | |
275 | { | |
276 | switch (feat_num) { | |
277 | case DCCPF_CCID: | |
278 | return val == DCCPC_CCID2 || val == DCCPC_CCID3; | |
279 | /* Type-check Boolean feature values: */ | |
280 | case DCCPF_SHORT_SEQNOS: | |
281 | case DCCPF_ECN_INCAPABLE: | |
282 | case DCCPF_SEND_ACK_VECTOR: | |
283 | case DCCPF_SEND_NDP_COUNT: | |
284 | case DCCPF_DATA_CHECKSUM: | |
285 | case DCCPF_SEND_LEV_RATE: | |
286 | return val < 2; | |
287 | case DCCPF_MIN_CSUM_COVER: | |
288 | return val < 16; | |
289 | } | |
290 | return 0; /* feature unknown */ | |
291 | } | |
292 | ||
293 | static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len) | |
294 | { | |
295 | if (sp_list == NULL || sp_len < 1) | |
296 | return 0; | |
297 | while (sp_len--) | |
298 | if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++)) | |
299 | return 0; | |
300 | return 1; | |
301 | } | |
302 | ||
303 | /** | |
304 | * __feat_register_nn - Register new NN value on socket | |
305 | * @fn: feature-negotiation list to register with | |
306 | * @feat: an NN feature from %dccp_feature_numbers | |
307 | * @mandatory: use Mandatory option if 1 | |
308 | * @nn_val: value to register (restricted to 4 bytes) | |
309 | * Note that NN features are local by definition (RFC 4340, 6.3.2). | |
310 | */ | |
311 | static int __feat_register_nn(struct list_head *fn, u8 feat, | |
312 | u8 mandatory, u64 nn_val) | |
313 | { | |
314 | dccp_feat_val fval = { .nn = nn_val }; | |
315 | ||
316 | if (dccp_feat_type(feat) != FEAT_NN || | |
317 | !dccp_feat_is_valid_nn_val(feat, nn_val)) | |
318 | return -EINVAL; | |
319 | ||
320 | /* Don't bother with default values, they will be activated anyway. */ | |
321 | if (nn_val - (u64)dccp_feat_default_value(feat) == 0) | |
322 | return 0; | |
323 | ||
324 | return dccp_feat_push_change(fn, feat, 1, mandatory, &fval); | |
325 | } | |
326 | ||
327 | /** | |
328 | * __feat_register_sp - Register new SP value/list on socket | |
329 | * @fn: feature-negotiation list to register with | |
330 | * @feat: an SP feature from %dccp_feature_numbers | |
331 | * @is_local: whether the local (1) or the remote (0) @feat is meant | |
332 | * @mandatory: use Mandatory option if 1 | |
333 | * @sp_val: SP value followed by optional preference list | |
334 | * @sp_len: length of @sp_val in bytes | |
335 | */ | |
336 | static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local, | |
337 | u8 mandatory, u8 const *sp_val, u8 sp_len) | |
338 | { | |
339 | dccp_feat_val fval; | |
340 | ||
341 | if (dccp_feat_type(feat) != FEAT_SP || | |
342 | !dccp_feat_sp_list_ok(feat, sp_val, sp_len)) | |
343 | return -EINVAL; | |
344 | ||
345 | /* Avoid negotiating alien CCIDs by only advertising supported ones */ | |
346 | if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len)) | |
347 | return -EOPNOTSUPP; | |
348 | ||
349 | if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len)) | |
350 | return -ENOMEM; | |
351 | ||
352 | return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval); | |
353 | } | |
354 | ||
355 | int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature, | |
356 | u8 *val, u8 len, gfp_t gfp) | |
357 | { | |
358 | struct dccp_opt_pend *opt; | |
359 | ||
360 | dccp_feat_debug(type, feature, *val); | |
361 | ||
362 | if (len > 3) { | |
363 | DCCP_WARN("invalid length %d\n", len); | |
364 | return -EINVAL; | |
365 | } | |
366 | /* XXX add further sanity checks */ | |
367 | ||
368 | /* check if that feature is already being negotiated */ | |
369 | list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { | |
370 | /* ok we found a negotiation for this option already */ | |
371 | if (opt->dccpop_feat == feature && opt->dccpop_type == type) { | |
372 | dccp_pr_debug("Replacing old\n"); | |
373 | /* replace */ | |
374 | BUG_ON(opt->dccpop_val == NULL); | |
375 | kfree(opt->dccpop_val); | |
376 | opt->dccpop_val = val; | |
377 | opt->dccpop_len = len; | |
378 | opt->dccpop_conf = 0; | |
379 | return 0; | |
380 | } | |
381 | } | |
382 | ||
383 | /* negotiation for a new feature */ | |
384 | opt = kmalloc(sizeof(*opt), gfp); | |
385 | if (opt == NULL) | |
386 | return -ENOMEM; | |
387 | ||
388 | opt->dccpop_type = type; | |
389 | opt->dccpop_feat = feature; | |
390 | opt->dccpop_len = len; | |
391 | opt->dccpop_val = val; | |
392 | opt->dccpop_conf = 0; | |
393 | opt->dccpop_sc = NULL; | |
394 | ||
395 | BUG_ON(opt->dccpop_val == NULL); | |
396 | ||
397 | list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending); | |
398 | return 0; | |
399 | } | |
400 | ||
401 | EXPORT_SYMBOL_GPL(dccp_feat_change); | |
402 | ||
403 | static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr) | |
404 | { | |
405 | struct dccp_sock *dp = dccp_sk(sk); | |
406 | struct dccp_minisock *dmsk = dccp_msk(sk); | |
407 | /* figure out if we are changing our CCID or the peer's */ | |
408 | const int rx = type == DCCPO_CHANGE_R; | |
409 | const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid; | |
410 | struct ccid *new_ccid; | |
411 | ||
412 | /* Check if nothing is being changed. */ | |
413 | if (ccid_nr == new_ccid_nr) | |
414 | return 0; | |
415 | ||
416 | new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC); | |
417 | if (new_ccid == NULL) | |
418 | return -ENOMEM; | |
419 | ||
420 | if (rx) { | |
421 | ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); | |
422 | dp->dccps_hc_rx_ccid = new_ccid; | |
423 | dmsk->dccpms_rx_ccid = new_ccid_nr; | |
424 | } else { | |
425 | ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); | |
426 | dp->dccps_hc_tx_ccid = new_ccid; | |
427 | dmsk->dccpms_tx_ccid = new_ccid_nr; | |
428 | } | |
429 | ||
430 | return 0; | |
431 | } | |
432 | ||
433 | static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val) | |
434 | { | |
435 | dccp_feat_debug(type, feat, val); | |
436 | ||
437 | switch (feat) { | |
438 | case DCCPF_CCID: | |
439 | return dccp_feat_update_ccid(sk, type, val); | |
440 | default: | |
441 | dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n", | |
442 | dccp_feat_typename(type), feat); | |
443 | break; | |
444 | } | |
445 | return 0; | |
446 | } | |
447 | ||
448 | static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt, | |
449 | u8 *rpref, u8 rlen) | |
450 | { | |
451 | struct dccp_sock *dp = dccp_sk(sk); | |
452 | u8 *spref, slen, *res = NULL; | |
453 | int i, j, rc, agree = 1; | |
454 | ||
455 | BUG_ON(rpref == NULL); | |
456 | ||
457 | /* check if we are the black sheep */ | |
458 | if (dp->dccps_role == DCCP_ROLE_CLIENT) { | |
459 | spref = rpref; | |
460 | slen = rlen; | |
461 | rpref = opt->dccpop_val; | |
462 | rlen = opt->dccpop_len; | |
463 | } else { | |
464 | spref = opt->dccpop_val; | |
465 | slen = opt->dccpop_len; | |
466 | } | |
467 | /* | |
468 | * Now we have server preference list in spref and client preference in | |
469 | * rpref | |
470 | */ | |
471 | BUG_ON(spref == NULL); | |
472 | BUG_ON(rpref == NULL); | |
473 | ||
474 | /* FIXME sanity check vals */ | |
475 | ||
476 | /* Are values in any order? XXX Lame "algorithm" here */ | |
477 | for (i = 0; i < slen; i++) { | |
478 | for (j = 0; j < rlen; j++) { | |
479 | if (spref[i] == rpref[j]) { | |
480 | res = &spref[i]; | |
481 | break; | |
482 | } | |
483 | } | |
484 | if (res) | |
485 | break; | |
486 | } | |
487 | ||
488 | /* we didn't agree on anything */ | |
489 | if (res == NULL) { | |
490 | /* confirm previous value */ | |
491 | switch (opt->dccpop_feat) { | |
492 | case DCCPF_CCID: | |
493 | /* XXX did i get this right? =P */ | |
494 | if (opt->dccpop_type == DCCPO_CHANGE_L) | |
495 | res = &dccp_msk(sk)->dccpms_tx_ccid; | |
496 | else | |
497 | res = &dccp_msk(sk)->dccpms_rx_ccid; | |
498 | break; | |
499 | ||
500 | default: | |
501 | DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat); | |
502 | /* XXX implement res */ | |
503 | return -EFAULT; | |
504 | } | |
505 | ||
506 | dccp_pr_debug("Don't agree... reconfirming %d\n", *res); | |
507 | agree = 0; /* this is used for mandatory options... */ | |
508 | } | |
509 | ||
510 | /* need to put result and our preference list */ | |
511 | rlen = 1 + opt->dccpop_len; | |
512 | rpref = kmalloc(rlen, GFP_ATOMIC); | |
513 | if (rpref == NULL) | |
514 | return -ENOMEM; | |
515 | ||
516 | *rpref = *res; | |
517 | memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len); | |
518 | ||
519 | /* put it in the "confirm queue" */ | |
520 | if (opt->dccpop_sc == NULL) { | |
521 | opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC); | |
522 | if (opt->dccpop_sc == NULL) { | |
523 | kfree(rpref); | |
524 | return -ENOMEM; | |
525 | } | |
526 | } else { | |
527 | /* recycle the confirm slot */ | |
528 | BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); | |
529 | kfree(opt->dccpop_sc->dccpoc_val); | |
530 | dccp_pr_debug("recycling confirm slot\n"); | |
531 | } | |
532 | memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc)); | |
533 | ||
534 | opt->dccpop_sc->dccpoc_val = rpref; | |
535 | opt->dccpop_sc->dccpoc_len = rlen; | |
536 | ||
537 | /* update the option on our side [we are about to send the confirm] */ | |
538 | rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res); | |
539 | if (rc) { | |
540 | kfree(opt->dccpop_sc->dccpoc_val); | |
541 | kfree(opt->dccpop_sc); | |
542 | opt->dccpop_sc = NULL; | |
543 | return rc; | |
544 | } | |
545 | ||
546 | dccp_pr_debug("Will confirm %d\n", *rpref); | |
547 | ||
548 | /* say we want to change to X but we just got a confirm X, suppress our | |
549 | * change | |
550 | */ | |
551 | if (!opt->dccpop_conf) { | |
552 | if (*opt->dccpop_val == *res) | |
553 | opt->dccpop_conf = 1; | |
554 | dccp_pr_debug("won't ask for change of same feature\n"); | |
555 | } | |
556 | ||
557 | return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */ | |
558 | } | |
559 | ||
560 | static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) | |
561 | { | |
562 | struct dccp_minisock *dmsk = dccp_msk(sk); | |
563 | struct dccp_opt_pend *opt; | |
564 | int rc = 1; | |
565 | u8 t; | |
566 | ||
567 | /* | |
568 | * We received a CHANGE. We gotta match it against our own preference | |
569 | * list. If we got a CHANGE_R it means it's a change for us, so we need | |
570 | * to compare our CHANGE_L list. | |
571 | */ | |
572 | if (type == DCCPO_CHANGE_L) | |
573 | t = DCCPO_CHANGE_R; | |
574 | else | |
575 | t = DCCPO_CHANGE_L; | |
576 | ||
577 | /* find our preference list for this feature */ | |
578 | list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { | |
579 | if (opt->dccpop_type != t || opt->dccpop_feat != feature) | |
580 | continue; | |
581 | ||
582 | /* find the winner from the two preference lists */ | |
583 | rc = dccp_feat_reconcile(sk, opt, val, len); | |
584 | break; | |
585 | } | |
586 | ||
587 | /* We didn't deal with the change. This can happen if we have no | |
588 | * preference list for the feature. In fact, it just shouldn't | |
589 | * happen---if we understand a feature, we should have a preference list | |
590 | * with at least the default value. | |
591 | */ | |
592 | BUG_ON(rc == 1); | |
593 | ||
594 | return rc; | |
595 | } | |
596 | ||
597 | static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) | |
598 | { | |
599 | struct dccp_opt_pend *opt; | |
600 | struct dccp_minisock *dmsk = dccp_msk(sk); | |
601 | u8 *copy; | |
602 | int rc; | |
603 | ||
604 | /* NN features must be Change L (sec. 6.3.2) */ | |
605 | if (type != DCCPO_CHANGE_L) { | |
606 | dccp_pr_debug("received %s for NN feature %d\n", | |
607 | dccp_feat_typename(type), feature); | |
608 | return -EFAULT; | |
609 | } | |
610 | ||
611 | /* XXX sanity check opt val */ | |
612 | ||
613 | /* copy option so we can confirm it */ | |
614 | opt = kzalloc(sizeof(*opt), GFP_ATOMIC); | |
615 | if (opt == NULL) | |
616 | return -ENOMEM; | |
617 | ||
618 | copy = kmemdup(val, len, GFP_ATOMIC); | |
619 | if (copy == NULL) { | |
620 | kfree(opt); | |
621 | return -ENOMEM; | |
622 | } | |
623 | ||
624 | opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */ | |
625 | opt->dccpop_feat = feature; | |
626 | opt->dccpop_val = copy; | |
627 | opt->dccpop_len = len; | |
628 | ||
629 | /* change feature */ | |
630 | rc = dccp_feat_update(sk, type, feature, *val); | |
631 | if (rc) { | |
632 | kfree(opt->dccpop_val); | |
633 | kfree(opt); | |
634 | return rc; | |
635 | } | |
636 | ||
637 | dccp_feat_debug(type, feature, *copy); | |
638 | ||
639 | list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); | |
640 | ||
641 | return 0; | |
642 | } | |
643 | ||
644 | static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk, | |
645 | u8 type, u8 feature) | |
646 | { | |
647 | /* XXX check if other confirms for that are queued and recycle slot */ | |
648 | struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC); | |
649 | ||
650 | if (opt == NULL) { | |
651 | /* XXX what do we do? Ignoring should be fine. It's a change | |
652 | * after all =P | |
653 | */ | |
654 | return; | |
655 | } | |
656 | ||
657 | switch (type) { | |
658 | case DCCPO_CHANGE_L: | |
659 | opt->dccpop_type = DCCPO_CONFIRM_R; | |
660 | break; | |
661 | case DCCPO_CHANGE_R: | |
662 | opt->dccpop_type = DCCPO_CONFIRM_L; | |
663 | break; | |
664 | default: | |
665 | DCCP_WARN("invalid type %d\n", type); | |
666 | kfree(opt); | |
667 | return; | |
668 | } | |
669 | opt->dccpop_feat = feature; | |
670 | opt->dccpop_val = NULL; | |
671 | opt->dccpop_len = 0; | |
672 | ||
673 | /* change feature */ | |
674 | dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature); | |
675 | ||
676 | list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); | |
677 | } | |
678 | ||
679 | static void dccp_feat_flush_confirm(struct sock *sk) | |
680 | { | |
681 | struct dccp_minisock *dmsk = dccp_msk(sk); | |
682 | /* Check if there is anything to confirm in the first place */ | |
683 | int yes = !list_empty(&dmsk->dccpms_conf); | |
684 | ||
685 | if (!yes) { | |
686 | struct dccp_opt_pend *opt; | |
687 | ||
688 | list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { | |
689 | if (opt->dccpop_conf) { | |
690 | yes = 1; | |
691 | break; | |
692 | } | |
693 | } | |
694 | } | |
695 | ||
696 | if (!yes) | |
697 | return; | |
698 | ||
699 | /* OK there is something to confirm... */ | |
700 | /* XXX check if packet is in flight? Send delayed ack?? */ | |
701 | if (sk->sk_state == DCCP_OPEN) | |
702 | dccp_send_ack(sk); | |
703 | } | |
704 | ||
705 | int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) | |
706 | { | |
707 | int rc; | |
708 | ||
709 | /* Ignore Change requests other than during connection setup */ | |
710 | if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING) | |
711 | return 0; | |
712 | dccp_feat_debug(type, feature, *val); | |
713 | ||
714 | /* figure out if it's SP or NN feature */ | |
715 | switch (feature) { | |
716 | /* deal with SP features */ | |
717 | case DCCPF_CCID: | |
718 | rc = dccp_feat_sp(sk, type, feature, val, len); | |
719 | break; | |
720 | ||
721 | /* deal with NN features */ | |
722 | case DCCPF_ACK_RATIO: | |
723 | rc = dccp_feat_nn(sk, type, feature, val, len); | |
724 | break; | |
725 | ||
726 | /* XXX implement other features */ | |
727 | default: | |
728 | dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n", | |
729 | dccp_feat_typename(type), feature); | |
730 | rc = -EFAULT; | |
731 | break; | |
732 | } | |
733 | ||
734 | /* check if there were problems changing features */ | |
735 | if (rc) { | |
736 | /* If we don't agree on SP, we sent a confirm for old value. | |
737 | * However we propagate rc to caller in case option was | |
738 | * mandatory | |
739 | */ | |
740 | if (rc != DCCP_FEAT_SP_NOAGREE) | |
741 | dccp_feat_empty_confirm(dccp_msk(sk), type, feature); | |
742 | } | |
743 | ||
744 | /* generate the confirm [if required] */ | |
745 | dccp_feat_flush_confirm(sk); | |
746 | ||
747 | return rc; | |
748 | } | |
749 | ||
750 | EXPORT_SYMBOL_GPL(dccp_feat_change_recv); | |
751 | ||
752 | int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, | |
753 | u8 *val, u8 len) | |
754 | { | |
755 | u8 t; | |
756 | struct dccp_opt_pend *opt; | |
757 | struct dccp_minisock *dmsk = dccp_msk(sk); | |
758 | int found = 0; | |
759 | int all_confirmed = 1; | |
760 | ||
761 | /* Ignore Confirm options other than during connection setup */ | |
762 | if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING) | |
763 | return 0; | |
764 | dccp_feat_debug(type, feature, *val); | |
765 | ||
766 | /* locate our change request */ | |
767 | switch (type) { | |
768 | case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break; | |
769 | case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break; | |
770 | default: DCCP_WARN("invalid type %d\n", type); | |
771 | return 1; | |
772 | ||
773 | } | |
774 | /* XXX sanity check feature value */ | |
775 | ||
776 | list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { | |
777 | if (!opt->dccpop_conf && opt->dccpop_type == t && | |
778 | opt->dccpop_feat == feature) { | |
779 | found = 1; | |
780 | dccp_pr_debug("feature %d found\n", opt->dccpop_feat); | |
781 | ||
782 | /* XXX do sanity check */ | |
783 | ||
784 | opt->dccpop_conf = 1; | |
785 | ||
786 | /* We got a confirmation---change the option */ | |
787 | dccp_feat_update(sk, opt->dccpop_type, | |
788 | opt->dccpop_feat, *val); | |
789 | ||
790 | /* XXX check the return value of dccp_feat_update */ | |
791 | break; | |
792 | } | |
793 | ||
794 | if (!opt->dccpop_conf) | |
795 | all_confirmed = 0; | |
796 | } | |
797 | ||
798 | if (!found) | |
799 | dccp_pr_debug("%s(%d, ...) never requested\n", | |
800 | dccp_feat_typename(type), feature); | |
801 | return 0; | |
802 | } | |
803 | ||
804 | EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv); | |
805 | ||
806 | void dccp_feat_clean(struct dccp_minisock *dmsk) | |
807 | { | |
808 | struct dccp_opt_pend *opt, *next; | |
809 | ||
810 | list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending, | |
811 | dccpop_node) { | |
812 | BUG_ON(opt->dccpop_val == NULL); | |
813 | kfree(opt->dccpop_val); | |
814 | ||
815 | if (opt->dccpop_sc != NULL) { | |
816 | BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); | |
817 | kfree(opt->dccpop_sc->dccpoc_val); | |
818 | kfree(opt->dccpop_sc); | |
819 | } | |
820 | ||
821 | kfree(opt); | |
822 | } | |
823 | INIT_LIST_HEAD(&dmsk->dccpms_pending); | |
824 | ||
825 | list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) { | |
826 | BUG_ON(opt == NULL); | |
827 | if (opt->dccpop_val != NULL) | |
828 | kfree(opt->dccpop_val); | |
829 | kfree(opt); | |
830 | } | |
831 | INIT_LIST_HEAD(&dmsk->dccpms_conf); | |
832 | } | |
833 | ||
834 | EXPORT_SYMBOL_GPL(dccp_feat_clean); | |
835 | ||
836 | /* this is to be called only when a listening sock creates its child. It is | |
837 | * assumed by the function---the confirm is not duplicated, but rather it is | |
838 | * "passed on". | |
839 | */ | |
840 | int dccp_feat_clone(struct sock *oldsk, struct sock *newsk) | |
841 | { | |
842 | struct dccp_minisock *olddmsk = dccp_msk(oldsk); | |
843 | struct dccp_minisock *newdmsk = dccp_msk(newsk); | |
844 | struct dccp_opt_pend *opt; | |
845 | int rc = 0; | |
846 | ||
847 | INIT_LIST_HEAD(&newdmsk->dccpms_pending); | |
848 | INIT_LIST_HEAD(&newdmsk->dccpms_conf); | |
849 | ||
850 | list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) { | |
851 | struct dccp_opt_pend *newopt; | |
852 | /* copy the value of the option */ | |
853 | u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC); | |
854 | ||
855 | if (val == NULL) | |
856 | goto out_clean; | |
857 | ||
858 | newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC); | |
859 | if (newopt == NULL) { | |
860 | kfree(val); | |
861 | goto out_clean; | |
862 | } | |
863 | ||
864 | /* insert the option */ | |
865 | newopt->dccpop_val = val; | |
866 | list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending); | |
867 | ||
868 | /* XXX what happens with backlogs and multiple connections at | |
869 | * once... | |
870 | */ | |
871 | /* the master socket no longer needs to worry about confirms */ | |
872 | opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */ | |
873 | ||
874 | /* reset state for a new socket */ | |
875 | opt->dccpop_conf = 0; | |
876 | } | |
877 | ||
878 | /* XXX not doing anything about the conf queue */ | |
879 | ||
880 | out: | |
881 | return rc; | |
882 | ||
883 | out_clean: | |
884 | dccp_feat_clean(newdmsk); | |
885 | rc = -ENOMEM; | |
886 | goto out; | |
887 | } | |
888 | ||
889 | EXPORT_SYMBOL_GPL(dccp_feat_clone); | |
890 | ||
891 | int dccp_feat_init(struct sock *sk) | |
892 | { | |
893 | struct dccp_sock *dp = dccp_sk(sk); | |
894 | struct dccp_minisock *dmsk = dccp_msk(sk); | |
895 | int rc; | |
896 | ||
897 | INIT_LIST_HEAD(&dmsk->dccpms_pending); /* XXX no longer used */ | |
898 | INIT_LIST_HEAD(&dmsk->dccpms_conf); /* XXX no longer used */ | |
899 | ||
900 | /* CCID L */ | |
901 | rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0, | |
902 | &dmsk->dccpms_tx_ccid, 1); | |
903 | if (rc) | |
904 | goto out; | |
905 | ||
906 | /* CCID R */ | |
907 | rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0, | |
908 | &dmsk->dccpms_rx_ccid, 1); | |
909 | if (rc) | |
910 | goto out; | |
911 | ||
912 | /* Ack ratio */ | |
913 | rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0, | |
914 | dmsk->dccpms_ack_ratio); | |
915 | out: | |
916 | return rc; | |
917 | } | |
918 | ||
919 | EXPORT_SYMBOL_GPL(dccp_feat_init); | |
920 | ||
921 | #ifdef CONFIG_IP_DCCP_DEBUG | |
922 | const char *dccp_feat_typename(const u8 type) | |
923 | { | |
924 | switch(type) { | |
925 | case DCCPO_CHANGE_L: return("ChangeL"); | |
926 | case DCCPO_CONFIRM_L: return("ConfirmL"); | |
927 | case DCCPO_CHANGE_R: return("ChangeR"); | |
928 | case DCCPO_CONFIRM_R: return("ConfirmR"); | |
929 | /* the following case must not appear in feature negotation */ | |
930 | default: dccp_pr_debug("unknown type %d [BUG!]\n", type); | |
931 | } | |
932 | return NULL; | |
933 | } | |
934 | ||
935 | EXPORT_SYMBOL_GPL(dccp_feat_typename); | |
936 | ||
937 | const char *dccp_feat_name(const u8 feat) | |
938 | { | |
939 | static const char *feature_names[] = { | |
940 | [DCCPF_RESERVED] = "Reserved", | |
941 | [DCCPF_CCID] = "CCID", | |
942 | [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos", | |
943 | [DCCPF_SEQUENCE_WINDOW] = "Sequence Window", | |
944 | [DCCPF_ECN_INCAPABLE] = "ECN Incapable", | |
945 | [DCCPF_ACK_RATIO] = "Ack Ratio", | |
946 | [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector", | |
947 | [DCCPF_SEND_NDP_COUNT] = "Send NDP Count", | |
948 | [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage", | |
949 | [DCCPF_DATA_CHECKSUM] = "Send Data Checksum", | |
950 | }; | |
951 | if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC) | |
952 | return feature_names[DCCPF_RESERVED]; | |
953 | ||
954 | if (feat == DCCPF_SEND_LEV_RATE) | |
955 | return "Send Loss Event Rate"; | |
956 | if (feat >= DCCPF_MIN_CCID_SPECIFIC) | |
957 | return "CCID-specific"; | |
958 | ||
959 | return feature_names[feat]; | |
960 | } | |
961 | ||
962 | EXPORT_SYMBOL_GPL(dccp_feat_name); | |
963 | #endif /* CONFIG_IP_DCCP_DEBUG */ |