Commit | Line | Data |
---|---|---|
afe00251 AB |
1 | /* |
2 | * net/dccp/feat.c | |
3 | * | |
63b8e286 GR |
4 | * Feature negotiation for the DCCP protocol (RFC 4340, section 6) |
5 | * | |
6 | * Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk> | |
7 | * Rewrote from scratch, some bits from earlier code by | |
8 | * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk> | |
9 | * | |
afe00251 | 10 | * |
5cdae198 GR |
11 | * ASSUMPTIONS |
12 | * ----------- | |
f74e91b6 GR |
13 | * o Feature negotiation is coordinated with connection setup (as in TCP), wild |
14 | * changes of parameters of an established connection are not supported. | |
5cdae198 GR |
15 | * o All currently known SP features have 1-byte quantities. If in the future |
16 | * extensions of RFCs 4340..42 define features with item lengths larger than | |
17 | * one byte, a feature-specific extension of the code will be required. | |
18 | * | |
19 | * This program is free software; you can redistribute it and/or | |
20 | * modify it under the terms of the GNU General Public License | |
21 | * as published by the Free Software Foundation; either version | |
22 | * 2 of the License, or (at your option) any later version. | |
afe00251 | 23 | */ |
afe00251 | 24 | #include <linux/module.h> |
6ffd30fb | 25 | #include "ccid.h" |
afe00251 AB |
26 | #include "feat.h" |
27 | ||
422d9cdc GR |
28 | /* |
29 | * Feature activation handlers. | |
30 | * | |
31 | * These all use an u64 argument, to provide enough room for NN/SP features. At | |
32 | * this stage the negotiated values have been checked to be within their range. | |
33 | */ | |
34 | static int dccp_hdlr_ccid(struct sock *sk, u64 ccid, bool rx) | |
35 | { | |
36 | struct dccp_sock *dp = dccp_sk(sk); | |
e5fd56ca | 37 | struct ccid *new_ccid = ccid_new(ccid, sk, rx); |
422d9cdc GR |
38 | |
39 | if (new_ccid == NULL) | |
40 | return -ENOMEM; | |
41 | ||
42 | if (rx) { | |
43 | ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); | |
44 | dp->dccps_hc_rx_ccid = new_ccid; | |
45 | } else { | |
46 | ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); | |
47 | dp->dccps_hc_tx_ccid = new_ccid; | |
48 | } | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static int dccp_hdlr_seq_win(struct sock *sk, u64 seq_win, bool rx) | |
53 | { | |
54 | if (!rx) | |
55 | dccp_msk(sk)->dccpms_sequence_window = seq_win; | |
56 | return 0; | |
57 | } | |
58 | ||
59 | static int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx) | |
60 | { | |
61 | if (rx) | |
62 | dccp_sk(sk)->dccps_r_ack_ratio = ratio; | |
63 | else | |
64 | dccp_sk(sk)->dccps_l_ack_ratio = ratio; | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static int dccp_hdlr_ackvec(struct sock *sk, u64 enable, bool rx) | |
69 | { | |
70 | struct dccp_sock *dp = dccp_sk(sk); | |
71 | ||
72 | if (rx) { | |
73 | if (enable && dp->dccps_hc_rx_ackvec == NULL) { | |
74 | dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(gfp_any()); | |
75 | if (dp->dccps_hc_rx_ackvec == NULL) | |
76 | return -ENOMEM; | |
77 | } else if (!enable) { | |
78 | dccp_ackvec_free(dp->dccps_hc_rx_ackvec); | |
79 | dp->dccps_hc_rx_ackvec = NULL; | |
80 | } | |
81 | } | |
82 | return 0; | |
83 | } | |
84 | ||
85 | static int dccp_hdlr_ndp(struct sock *sk, u64 enable, bool rx) | |
86 | { | |
87 | if (!rx) | |
4098dce5 | 88 | dccp_sk(sk)->dccps_send_ndp_count = (enable > 0); |
422d9cdc GR |
89 | return 0; |
90 | } | |
91 | ||
92 | /* | |
93 | * Minimum Checksum Coverage is located at the RX side (9.2.1). This means that | |
94 | * `rx' holds when the sending peer informs about his partial coverage via a | |
95 | * ChangeR() option. In the other case, we are the sender and the receiver | |
96 | * announces its coverage via ChangeL() options. The policy here is to honour | |
97 | * such communication by enabling the corresponding partial coverage - but only | |
98 | * if it has not been set manually before; the warning here means that all | |
99 | * packets will be dropped. | |
100 | */ | |
101 | static int dccp_hdlr_min_cscov(struct sock *sk, u64 cscov, bool rx) | |
102 | { | |
103 | struct dccp_sock *dp = dccp_sk(sk); | |
104 | ||
105 | if (rx) | |
106 | dp->dccps_pcrlen = cscov; | |
107 | else { | |
108 | if (dp->dccps_pcslen == 0) | |
109 | dp->dccps_pcslen = cscov; | |
110 | else if (cscov > dp->dccps_pcslen) | |
111 | DCCP_WARN("CsCov %u too small, peer requires >= %u\n", | |
112 | dp->dccps_pcslen, (u8)cscov); | |
113 | } | |
114 | return 0; | |
115 | } | |
116 | ||
7d43d1a0 GR |
117 | static const struct { |
118 | u8 feat_num; /* DCCPF_xxx */ | |
119 | enum dccp_feat_type rxtx; /* RX or TX */ | |
120 | enum dccp_feat_type reconciliation; /* SP or NN */ | |
121 | u8 default_value; /* as in 6.4 */ | |
422d9cdc | 122 | int (*activation_hdlr)(struct sock *sk, u64 val, bool rx); |
7d43d1a0 GR |
123 | /* |
124 | * Lookup table for location and type of features (from RFC 4340/4342) | |
125 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
126 | * | Feature | Location | Reconc. | Initial | Section | | |
127 | * | | RX | TX | SP | NN | Value | Reference | | |
128 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
129 | * | DCCPF_CCID | | X | X | | 2 | 10 | | |
130 | * | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 | | |
131 | * | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 | | |
132 | * | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 | | |
133 | * | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 | | |
134 | * | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 | | |
135 | * | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 | | |
136 | * | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 | | |
137 | * | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 | | |
138 | * | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 | | |
139 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
140 | */ | |
141 | } dccp_feat_table[] = { | |
422d9cdc GR |
142 | { DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2, dccp_hdlr_ccid }, |
143 | { DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0, NULL }, | |
144 | { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100, dccp_hdlr_seq_win }, | |
145 | { DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0, NULL }, | |
146 | { DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2, dccp_hdlr_ack_ratio}, | |
147 | { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_ackvec }, | |
148 | { DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0, dccp_hdlr_ndp }, | |
149 | { DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_min_cscov}, | |
150 | { DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0, NULL }, | |
151 | { DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0, NULL }, | |
7d43d1a0 GR |
152 | }; |
153 | #define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table) | |
154 | ||
61e6473e GR |
155 | /** |
156 | * dccp_feat_index - Hash function to map feature number into array position | |
157 | * Returns consecutive array index or -1 if the feature is not understood. | |
158 | */ | |
159 | static int dccp_feat_index(u8 feat_num) | |
160 | { | |
161 | /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */ | |
162 | if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM) | |
163 | return feat_num - 1; | |
164 | ||
165 | /* | |
166 | * Other features: add cases for new feature types here after adding | |
167 | * them to the above table. | |
168 | */ | |
169 | switch (feat_num) { | |
170 | case DCCPF_SEND_LEV_RATE: | |
171 | return DCCP_FEAT_SUPPORTED_MAX - 1; | |
172 | } | |
173 | return -1; | |
174 | } | |
175 | ||
176 | static u8 dccp_feat_type(u8 feat_num) | |
177 | { | |
178 | int idx = dccp_feat_index(feat_num); | |
179 | ||
180 | if (idx < 0) | |
181 | return FEAT_UNKNOWN; | |
182 | return dccp_feat_table[idx].reconciliation; | |
183 | } | |
184 | ||
e8ef967a GR |
185 | static int dccp_feat_default_value(u8 feat_num) |
186 | { | |
187 | int idx = dccp_feat_index(feat_num); | |
188 | /* | |
189 | * There are no default values for unknown features, so encountering a | |
190 | * negative index here indicates a serious problem somewhere else. | |
191 | */ | |
192 | DCCP_BUG_ON(idx < 0); | |
193 | ||
194 | return idx < 0 ? 0 : dccp_feat_table[idx].default_value; | |
195 | } | |
196 | ||
422d9cdc GR |
197 | static int __dccp_feat_activate(struct sock *sk, const int idx, |
198 | const bool is_local, dccp_feat_val const *fval) | |
199 | { | |
200 | bool rx; | |
201 | u64 val; | |
202 | ||
203 | if (idx < 0 || idx >= DCCP_FEAT_SUPPORTED_MAX) | |
204 | return -1; | |
205 | if (dccp_feat_table[idx].activation_hdlr == NULL) | |
206 | return 0; | |
207 | ||
208 | if (fval == NULL) { | |
209 | val = dccp_feat_table[idx].default_value; | |
210 | } else if (dccp_feat_table[idx].reconciliation == FEAT_SP) { | |
211 | if (fval->sp.vec == NULL) { | |
212 | /* | |
213 | * This can happen when an empty Confirm is sent | |
214 | * for an SP (i.e. known) feature. In this case | |
215 | * we would be using the default anyway. | |
216 | */ | |
217 | DCCP_CRIT("Feature #%d undefined: using default", idx); | |
218 | val = dccp_feat_table[idx].default_value; | |
219 | } else { | |
220 | val = fval->sp.vec[0]; | |
221 | } | |
222 | } else { | |
223 | val = fval->nn; | |
224 | } | |
225 | ||
226 | /* Location is RX if this is a local-RX or remote-TX feature */ | |
227 | rx = (is_local == (dccp_feat_table[idx].rxtx == FEAT_AT_RX)); | |
228 | ||
229 | return dccp_feat_table[idx].activation_hdlr(sk, val, rx); | |
230 | } | |
231 | ||
b1ad0042 GR |
232 | /* Test for "Req'd" feature (RFC 4340, 6.4) */ |
233 | static inline int dccp_feat_must_be_understood(u8 feat_num) | |
234 | { | |
235 | return feat_num == DCCPF_CCID || feat_num == DCCPF_SHORT_SEQNOS || | |
236 | feat_num == DCCPF_SEQUENCE_WINDOW; | |
237 | } | |
238 | ||
ac75773c GR |
239 | /* copy constructor, fval must not already contain allocated memory */ |
240 | static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len) | |
241 | { | |
242 | fval->sp.len = len; | |
243 | if (fval->sp.len > 0) { | |
244 | fval->sp.vec = kmemdup(val, len, gfp_any()); | |
245 | if (fval->sp.vec == NULL) { | |
246 | fval->sp.len = 0; | |
247 | return -ENOBUFS; | |
248 | } | |
249 | } | |
250 | return 0; | |
251 | } | |
252 | ||
61e6473e GR |
253 | static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val) |
254 | { | |
255 | if (unlikely(val == NULL)) | |
256 | return; | |
257 | if (dccp_feat_type(feat_num) == FEAT_SP) | |
258 | kfree(val->sp.vec); | |
259 | memset(val, 0, sizeof(*val)); | |
260 | } | |
261 | ||
ac75773c GR |
262 | static struct dccp_feat_entry * |
263 | dccp_feat_clone_entry(struct dccp_feat_entry const *original) | |
264 | { | |
265 | struct dccp_feat_entry *new; | |
266 | u8 type = dccp_feat_type(original->feat_num); | |
267 | ||
268 | if (type == FEAT_UNKNOWN) | |
269 | return NULL; | |
270 | ||
271 | new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any()); | |
272 | if (new == NULL) | |
273 | return NULL; | |
274 | ||
275 | if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val, | |
276 | original->val.sp.vec, | |
277 | original->val.sp.len)) { | |
278 | kfree(new); | |
279 | return NULL; | |
280 | } | |
281 | return new; | |
282 | } | |
283 | ||
61e6473e GR |
284 | static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry) |
285 | { | |
286 | if (entry != NULL) { | |
287 | dccp_feat_val_destructor(entry->feat_num, &entry->val); | |
288 | kfree(entry); | |
289 | } | |
290 | } | |
291 | ||
292 | /* | |
293 | * List management functions | |
294 | * | |
295 | * Feature negotiation lists rely on and maintain the following invariants: | |
296 | * - each feat_num in the list is known, i.e. we know its type and default value | |
297 | * - each feat_num/is_local combination is unique (old entries are overwritten) | |
298 | * - SP values are always freshly allocated | |
299 | * - list is sorted in increasing order of feature number (faster lookup) | |
300 | */ | |
0c116839 GR |
301 | static struct dccp_feat_entry *dccp_feat_list_lookup(struct list_head *fn_list, |
302 | u8 feat_num, bool is_local) | |
303 | { | |
304 | struct dccp_feat_entry *entry; | |
305 | ||
3d3e35aa | 306 | list_for_each_entry(entry, fn_list, node) { |
0c116839 GR |
307 | if (entry->feat_num == feat_num && entry->is_local == is_local) |
308 | return entry; | |
309 | else if (entry->feat_num > feat_num) | |
310 | break; | |
3d3e35aa | 311 | } |
0c116839 GR |
312 | return NULL; |
313 | } | |
61e6473e | 314 | |
e8ef967a GR |
315 | /** |
316 | * dccp_feat_entry_new - Central list update routine (called by all others) | |
317 | * @head: list to add to | |
318 | * @feat: feature number | |
319 | * @local: whether the local (1) or remote feature with number @feat is meant | |
320 | * This is the only constructor and serves to ensure the above invariants. | |
321 | */ | |
322 | static struct dccp_feat_entry * | |
323 | dccp_feat_entry_new(struct list_head *head, u8 feat, bool local) | |
324 | { | |
325 | struct dccp_feat_entry *entry; | |
326 | ||
327 | list_for_each_entry(entry, head, node) | |
328 | if (entry->feat_num == feat && entry->is_local == local) { | |
329 | dccp_feat_val_destructor(entry->feat_num, &entry->val); | |
330 | return entry; | |
331 | } else if (entry->feat_num > feat) { | |
332 | head = &entry->node; | |
333 | break; | |
334 | } | |
335 | ||
336 | entry = kmalloc(sizeof(*entry), gfp_any()); | |
337 | if (entry != NULL) { | |
338 | entry->feat_num = feat; | |
339 | entry->is_local = local; | |
340 | list_add_tail(&entry->node, head); | |
341 | } | |
342 | return entry; | |
343 | } | |
344 | ||
345 | /** | |
346 | * dccp_feat_push_change - Add/overwrite a Change option in the list | |
347 | * @fn_list: feature-negotiation list to update | |
348 | * @feat: one of %dccp_feature_numbers | |
349 | * @local: whether local (1) or remote (0) @feat_num is meant | |
350 | * @needs_mandatory: whether to use Mandatory feature negotiation options | |
351 | * @fval: pointer to NN/SP value to be inserted (will be copied) | |
352 | */ | |
353 | static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local, | |
354 | u8 mandatory, dccp_feat_val *fval) | |
355 | { | |
356 | struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); | |
357 | ||
358 | if (new == NULL) | |
359 | return -ENOMEM; | |
360 | ||
361 | new->feat_num = feat; | |
362 | new->is_local = local; | |
363 | new->state = FEAT_INITIALISING; | |
364 | new->needs_confirm = 0; | |
365 | new->empty_confirm = 0; | |
366 | new->val = *fval; | |
367 | new->needs_mandatory = mandatory; | |
368 | ||
369 | return 0; | |
370 | } | |
371 | ||
e77b8363 GR |
372 | /** |
373 | * dccp_feat_push_confirm - Add a Confirm entry to the FN list | |
374 | * @fn_list: feature-negotiation list to add to | |
375 | * @feat: one of %dccp_feature_numbers | |
376 | * @local: whether local (1) or remote (0) @feat_num is being confirmed | |
377 | * @fval: pointer to NN/SP value to be inserted or NULL | |
378 | * Returns 0 on success, a Reset code for further processing otherwise. | |
379 | */ | |
380 | static int dccp_feat_push_confirm(struct list_head *fn_list, u8 feat, u8 local, | |
381 | dccp_feat_val *fval) | |
382 | { | |
383 | struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); | |
384 | ||
385 | if (new == NULL) | |
386 | return DCCP_RESET_CODE_TOO_BUSY; | |
387 | ||
388 | new->feat_num = feat; | |
389 | new->is_local = local; | |
390 | new->state = FEAT_STABLE; /* transition in 6.6.2 */ | |
391 | new->needs_confirm = 1; | |
392 | new->empty_confirm = (fval == NULL); | |
393 | new->val.nn = 0; /* zeroes the whole structure */ | |
394 | if (!new->empty_confirm) | |
395 | new->val = *fval; | |
396 | new->needs_mandatory = 0; | |
397 | ||
398 | return 0; | |
399 | } | |
400 | ||
401 | static int dccp_push_empty_confirm(struct list_head *fn_list, u8 feat, u8 local) | |
402 | { | |
403 | return dccp_feat_push_confirm(fn_list, feat, local, NULL); | |
404 | } | |
405 | ||
61e6473e GR |
406 | static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry) |
407 | { | |
408 | list_del(&entry->node); | |
409 | dccp_feat_entry_destructor(entry); | |
410 | } | |
411 | ||
412 | void dccp_feat_list_purge(struct list_head *fn_list) | |
413 | { | |
414 | struct dccp_feat_entry *entry, *next; | |
415 | ||
416 | list_for_each_entry_safe(entry, next, fn_list, node) | |
417 | dccp_feat_entry_destructor(entry); | |
418 | INIT_LIST_HEAD(fn_list); | |
419 | } | |
420 | EXPORT_SYMBOL_GPL(dccp_feat_list_purge); | |
421 | ||
ac75773c GR |
422 | /* generate @to as full clone of @from - @to must not contain any nodes */ |
423 | int dccp_feat_clone_list(struct list_head const *from, struct list_head *to) | |
424 | { | |
425 | struct dccp_feat_entry *entry, *new; | |
426 | ||
427 | INIT_LIST_HEAD(to); | |
428 | list_for_each_entry(entry, from, node) { | |
429 | new = dccp_feat_clone_entry(entry); | |
430 | if (new == NULL) | |
431 | goto cloning_failed; | |
432 | list_add_tail(&new->node, to); | |
433 | } | |
434 | return 0; | |
435 | ||
436 | cloning_failed: | |
437 | dccp_feat_list_purge(to); | |
438 | return -ENOMEM; | |
439 | } | |
440 | ||
0971d17c GR |
441 | /** |
442 | * dccp_feat_valid_nn_length - Enforce length constraints on NN options | |
443 | * Length is between 0 and %DCCP_OPTVAL_MAXLEN. Used for outgoing packets only, | |
444 | * incoming options are accepted as long as their values are valid. | |
445 | */ | |
446 | static u8 dccp_feat_valid_nn_length(u8 feat_num) | |
447 | { | |
448 | if (feat_num == DCCPF_ACK_RATIO) /* RFC 4340, 11.3 and 6.6.8 */ | |
449 | return 2; | |
450 | if (feat_num == DCCPF_SEQUENCE_WINDOW) /* RFC 4340, 7.5.2 and 6.5 */ | |
451 | return 6; | |
452 | return 0; | |
453 | } | |
454 | ||
e8ef967a GR |
455 | static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val) |
456 | { | |
457 | switch (feat_num) { | |
458 | case DCCPF_ACK_RATIO: | |
459 | return val <= DCCPF_ACK_RATIO_MAX; | |
460 | case DCCPF_SEQUENCE_WINDOW: | |
461 | return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX; | |
462 | } | |
463 | return 0; /* feature unknown - so we can't tell */ | |
464 | } | |
465 | ||
466 | /* check that SP values are within the ranges defined in RFC 4340 */ | |
467 | static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val) | |
468 | { | |
469 | switch (feat_num) { | |
470 | case DCCPF_CCID: | |
471 | return val == DCCPC_CCID2 || val == DCCPC_CCID3; | |
472 | /* Type-check Boolean feature values: */ | |
473 | case DCCPF_SHORT_SEQNOS: | |
474 | case DCCPF_ECN_INCAPABLE: | |
475 | case DCCPF_SEND_ACK_VECTOR: | |
476 | case DCCPF_SEND_NDP_COUNT: | |
477 | case DCCPF_DATA_CHECKSUM: | |
478 | case DCCPF_SEND_LEV_RATE: | |
479 | return val < 2; | |
480 | case DCCPF_MIN_CSUM_COVER: | |
481 | return val < 16; | |
482 | } | |
483 | return 0; /* feature unknown */ | |
484 | } | |
485 | ||
486 | static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len) | |
487 | { | |
488 | if (sp_list == NULL || sp_len < 1) | |
489 | return 0; | |
490 | while (sp_len--) | |
491 | if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++)) | |
492 | return 0; | |
493 | return 1; | |
494 | } | |
495 | ||
0971d17c GR |
496 | /** |
497 | * dccp_feat_insert_opts - Generate FN options from current list state | |
498 | * @skb: next sk_buff to be sent to the peer | |
499 | * @dp: for client during handshake and general negotiation | |
500 | * @dreq: used by the server only (all Changes/Confirms in LISTEN/RESPOND) | |
501 | */ | |
502 | int dccp_feat_insert_opts(struct dccp_sock *dp, struct dccp_request_sock *dreq, | |
503 | struct sk_buff *skb) | |
504 | { | |
505 | struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg; | |
506 | struct dccp_feat_entry *pos, *next; | |
507 | u8 opt, type, len, *ptr, nn_in_nbo[DCCP_OPTVAL_MAXLEN]; | |
508 | bool rpt; | |
509 | ||
510 | /* put entries into @skb in the order they appear in the list */ | |
511 | list_for_each_entry_safe_reverse(pos, next, fn, node) { | |
512 | opt = dccp_feat_genopt(pos); | |
513 | type = dccp_feat_type(pos->feat_num); | |
514 | rpt = false; | |
515 | ||
516 | if (pos->empty_confirm) { | |
517 | len = 0; | |
518 | ptr = NULL; | |
519 | } else { | |
520 | if (type == FEAT_SP) { | |
521 | len = pos->val.sp.len; | |
522 | ptr = pos->val.sp.vec; | |
523 | rpt = pos->needs_confirm; | |
524 | } else if (type == FEAT_NN) { | |
525 | len = dccp_feat_valid_nn_length(pos->feat_num); | |
526 | ptr = nn_in_nbo; | |
527 | dccp_encode_value_var(pos->val.nn, ptr, len); | |
528 | } else { | |
529 | DCCP_BUG("unknown feature %u", pos->feat_num); | |
530 | return -1; | |
531 | } | |
532 | } | |
533 | ||
534 | if (dccp_insert_fn_opt(skb, opt, pos->feat_num, ptr, len, rpt)) | |
535 | return -1; | |
536 | if (pos->needs_mandatory && dccp_insert_option_mandatory(skb)) | |
537 | return -1; | |
538 | /* | |
539 | * Enter CHANGING after transmitting the Change option (6.6.2). | |
540 | */ | |
541 | if (pos->state == FEAT_INITIALISING) | |
542 | pos->state = FEAT_CHANGING; | |
543 | } | |
544 | return 0; | |
545 | } | |
546 | ||
e8ef967a GR |
547 | /** |
548 | * __feat_register_nn - Register new NN value on socket | |
549 | * @fn: feature-negotiation list to register with | |
550 | * @feat: an NN feature from %dccp_feature_numbers | |
551 | * @mandatory: use Mandatory option if 1 | |
552 | * @nn_val: value to register (restricted to 4 bytes) | |
553 | * Note that NN features are local by definition (RFC 4340, 6.3.2). | |
554 | */ | |
555 | static int __feat_register_nn(struct list_head *fn, u8 feat, | |
556 | u8 mandatory, u64 nn_val) | |
557 | { | |
558 | dccp_feat_val fval = { .nn = nn_val }; | |
559 | ||
560 | if (dccp_feat_type(feat) != FEAT_NN || | |
561 | !dccp_feat_is_valid_nn_val(feat, nn_val)) | |
562 | return -EINVAL; | |
563 | ||
564 | /* Don't bother with default values, they will be activated anyway. */ | |
565 | if (nn_val - (u64)dccp_feat_default_value(feat) == 0) | |
566 | return 0; | |
567 | ||
568 | return dccp_feat_push_change(fn, feat, 1, mandatory, &fval); | |
569 | } | |
570 | ||
571 | /** | |
572 | * __feat_register_sp - Register new SP value/list on socket | |
573 | * @fn: feature-negotiation list to register with | |
574 | * @feat: an SP feature from %dccp_feature_numbers | |
575 | * @is_local: whether the local (1) or the remote (0) @feat is meant | |
576 | * @mandatory: use Mandatory option if 1 | |
577 | * @sp_val: SP value followed by optional preference list | |
578 | * @sp_len: length of @sp_val in bytes | |
579 | */ | |
580 | static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local, | |
581 | u8 mandatory, u8 const *sp_val, u8 sp_len) | |
582 | { | |
583 | dccp_feat_val fval; | |
584 | ||
585 | if (dccp_feat_type(feat) != FEAT_SP || | |
586 | !dccp_feat_sp_list_ok(feat, sp_val, sp_len)) | |
587 | return -EINVAL; | |
588 | ||
d90ebcbf GR |
589 | /* Avoid negotiating alien CCIDs by only advertising supported ones */ |
590 | if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len)) | |
591 | return -EOPNOTSUPP; | |
592 | ||
e8ef967a GR |
593 | if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len)) |
594 | return -ENOMEM; | |
595 | ||
596 | return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval); | |
597 | } | |
598 | ||
49aebc66 GR |
599 | /** |
600 | * dccp_feat_register_sp - Register requests to change SP feature values | |
601 | * @sk: client or listening socket | |
602 | * @feat: one of %dccp_feature_numbers | |
603 | * @is_local: whether the local (1) or remote (0) @feat is meant | |
604 | * @list: array of preferred values, in descending order of preference | |
605 | * @len: length of @list in bytes | |
606 | */ | |
607 | int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local, | |
608 | u8 const *list, u8 len) | |
609 | { /* any changes must be registered before establishing the connection */ | |
610 | if (sk->sk_state != DCCP_CLOSED) | |
611 | return -EISCONN; | |
612 | if (dccp_feat_type(feat) != FEAT_SP) | |
19443178 | 613 | return -EINVAL; |
49aebc66 GR |
614 | return __feat_register_sp(&dccp_sk(sk)->dccps_featneg, feat, is_local, |
615 | 0, list, len); | |
afe00251 AB |
616 | } |
617 | ||
49aebc66 GR |
618 | /* Analogous to dccp_feat_register_sp(), but for non-negotiable values */ |
619 | int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val) | |
620 | { | |
621 | /* any changes must be registered before establishing the connection */ | |
622 | if (sk->sk_state != DCCP_CLOSED) | |
623 | return -EISCONN; | |
624 | if (dccp_feat_type(feat) != FEAT_NN) | |
625 | return -EINVAL; | |
626 | return __feat_register_nn(&dccp_sk(sk)->dccps_featneg, feat, 0, val); | |
627 | } | |
afe00251 | 628 | |
9eca0a47 GR |
629 | /* |
630 | * Tracking features whose value depend on the choice of CCID | |
631 | * | |
632 | * This is designed with an extension in mind so that a list walk could be done | |
633 | * before activating any features. However, the existing framework was found to | |
634 | * work satisfactorily up until now, the automatic verification is left open. | |
635 | * When adding new CCIDs, add a corresponding dependency table here. | |
636 | */ | |
637 | static const struct ccid_dependency *dccp_feat_ccid_deps(u8 ccid, bool is_local) | |
638 | { | |
639 | static const struct ccid_dependency ccid2_dependencies[2][2] = { | |
640 | /* | |
641 | * CCID2 mandates Ack Vectors (RFC 4341, 4.): as CCID is a TX | |
642 | * feature and Send Ack Vector is an RX feature, `is_local' | |
643 | * needs to be reversed. | |
644 | */ | |
645 | { /* Dependencies of the receiver-side (remote) CCID2 */ | |
646 | { | |
647 | .dependent_feat = DCCPF_SEND_ACK_VECTOR, | |
648 | .is_local = true, | |
649 | .is_mandatory = true, | |
650 | .val = 1 | |
651 | }, | |
652 | { 0, 0, 0, 0 } | |
653 | }, | |
654 | { /* Dependencies of the sender-side (local) CCID2 */ | |
655 | { | |
656 | .dependent_feat = DCCPF_SEND_ACK_VECTOR, | |
657 | .is_local = false, | |
658 | .is_mandatory = true, | |
659 | .val = 1 | |
660 | }, | |
661 | { 0, 0, 0, 0 } | |
662 | } | |
663 | }; | |
664 | static const struct ccid_dependency ccid3_dependencies[2][5] = { | |
665 | { /* | |
666 | * Dependencies of the receiver-side CCID3 | |
667 | */ | |
668 | { /* locally disable Ack Vectors */ | |
669 | .dependent_feat = DCCPF_SEND_ACK_VECTOR, | |
670 | .is_local = true, | |
671 | .is_mandatory = false, | |
672 | .val = 0 | |
673 | }, | |
674 | { /* see below why Send Loss Event Rate is on */ | |
675 | .dependent_feat = DCCPF_SEND_LEV_RATE, | |
676 | .is_local = true, | |
677 | .is_mandatory = true, | |
678 | .val = 1 | |
679 | }, | |
680 | { /* NDP Count is needed as per RFC 4342, 6.1.1 */ | |
681 | .dependent_feat = DCCPF_SEND_NDP_COUNT, | |
682 | .is_local = false, | |
683 | .is_mandatory = true, | |
684 | .val = 1 | |
685 | }, | |
686 | { 0, 0, 0, 0 }, | |
687 | }, | |
688 | { /* | |
689 | * CCID3 at the TX side: we request that the HC-receiver | |
690 | * will not send Ack Vectors (they will be ignored, so | |
691 | * Mandatory is not set); we enable Send Loss Event Rate | |
692 | * (Mandatory since the implementation does not support | |
693 | * the Loss Intervals option of RFC 4342, 8.6). | |
694 | * The last two options are for peer's information only. | |
695 | */ | |
696 | { | |
697 | .dependent_feat = DCCPF_SEND_ACK_VECTOR, | |
698 | .is_local = false, | |
699 | .is_mandatory = false, | |
700 | .val = 0 | |
701 | }, | |
702 | { | |
703 | .dependent_feat = DCCPF_SEND_LEV_RATE, | |
704 | .is_local = false, | |
705 | .is_mandatory = true, | |
706 | .val = 1 | |
707 | }, | |
708 | { /* this CCID does not support Ack Ratio */ | |
709 | .dependent_feat = DCCPF_ACK_RATIO, | |
710 | .is_local = true, | |
711 | .is_mandatory = false, | |
712 | .val = 0 | |
713 | }, | |
714 | { /* tell receiver we are sending NDP counts */ | |
715 | .dependent_feat = DCCPF_SEND_NDP_COUNT, | |
716 | .is_local = true, | |
717 | .is_mandatory = false, | |
718 | .val = 1 | |
719 | }, | |
720 | { 0, 0, 0, 0 } | |
721 | } | |
722 | }; | |
723 | switch (ccid) { | |
724 | case DCCPC_CCID2: | |
725 | return ccid2_dependencies[is_local]; | |
726 | case DCCPC_CCID3: | |
727 | return ccid3_dependencies[is_local]; | |
728 | default: | |
729 | return NULL; | |
730 | } | |
731 | } | |
732 | ||
733 | /** | |
734 | * dccp_feat_propagate_ccid - Resolve dependencies of features on choice of CCID | |
735 | * @fn: feature-negotiation list to update | |
736 | * @id: CCID number to track | |
737 | * @is_local: whether TX CCID (1) or RX CCID (0) is meant | |
738 | * This function needs to be called after registering all other features. | |
739 | */ | |
740 | static int dccp_feat_propagate_ccid(struct list_head *fn, u8 id, bool is_local) | |
741 | { | |
742 | const struct ccid_dependency *table = dccp_feat_ccid_deps(id, is_local); | |
743 | int i, rc = (table == NULL); | |
744 | ||
745 | for (i = 0; rc == 0 && table[i].dependent_feat != DCCPF_RESERVED; i++) | |
746 | if (dccp_feat_type(table[i].dependent_feat) == FEAT_SP) | |
747 | rc = __feat_register_sp(fn, table[i].dependent_feat, | |
748 | table[i].is_local, | |
749 | table[i].is_mandatory, | |
750 | &table[i].val, 1); | |
751 | else | |
752 | rc = __feat_register_nn(fn, table[i].dependent_feat, | |
753 | table[i].is_mandatory, | |
754 | table[i].val); | |
755 | return rc; | |
756 | } | |
757 | ||
758 | /** | |
759 | * dccp_feat_finalise_settings - Finalise settings before starting negotiation | |
760 | * @dp: client or listening socket (settings will be inherited) | |
761 | * This is called after all registrations (socket initialisation, sysctls, and | |
762 | * sockopt calls), and before sending the first packet containing Change options | |
763 | * (ie. client-Request or server-Response), to ensure internal consistency. | |
764 | */ | |
765 | int dccp_feat_finalise_settings(struct dccp_sock *dp) | |
766 | { | |
767 | struct list_head *fn = &dp->dccps_featneg; | |
768 | struct dccp_feat_entry *entry; | |
769 | int i = 2, ccids[2] = { -1, -1 }; | |
770 | ||
771 | /* | |
772 | * Propagating CCIDs: | |
773 | * 1) not useful to propagate CCID settings if this host advertises more | |
774 | * than one CCID: the choice of CCID may still change - if this is | |
775 | * the client, or if this is the server and the client sends | |
776 | * singleton CCID values. | |
777 | * 2) since is that propagate_ccid changes the list, we defer changing | |
778 | * the sorted list until after the traversal. | |
779 | */ | |
780 | list_for_each_entry(entry, fn, node) | |
781 | if (entry->feat_num == DCCPF_CCID && entry->val.sp.len == 1) | |
782 | ccids[entry->is_local] = entry->val.sp.vec[0]; | |
783 | while (i--) | |
784 | if (ccids[i] > 0 && dccp_feat_propagate_ccid(fn, ccids[i], i)) | |
785 | return -1; | |
786 | return 0; | |
787 | } | |
788 | ||
0c116839 GR |
789 | /** |
790 | * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features | |
791 | * It is the server which resolves the dependencies once the CCID has been | |
792 | * fully negotiated. If no CCID has been negotiated, it uses the default CCID. | |
793 | */ | |
794 | int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq) | |
795 | { | |
796 | struct list_head *fn = &dreq->dreq_featneg; | |
797 | struct dccp_feat_entry *entry; | |
798 | u8 is_local, ccid; | |
799 | ||
800 | for (is_local = 0; is_local <= 1; is_local++) { | |
801 | entry = dccp_feat_list_lookup(fn, DCCPF_CCID, is_local); | |
802 | ||
803 | if (entry != NULL && !entry->empty_confirm) | |
804 | ccid = entry->val.sp.vec[0]; | |
805 | else | |
806 | ccid = dccp_feat_default_value(DCCPF_CCID); | |
807 | ||
808 | if (dccp_feat_propagate_ccid(fn, ccid, is_local)) | |
809 | return -1; | |
810 | } | |
811 | return 0; | |
812 | } | |
813 | ||
75757a7d GR |
814 | /* Select the first entry in @servlist that also occurs in @clilist (6.3.1) */ |
815 | static int dccp_feat_preflist_match(u8 *servlist, u8 slen, u8 *clilist, u8 clen) | |
816 | { | |
817 | u8 c, s; | |
818 | ||
819 | for (s = 0; s < slen; s++) | |
820 | for (c = 0; c < clen; c++) | |
821 | if (servlist[s] == clilist[c]) | |
822 | return servlist[s]; | |
823 | return -1; | |
824 | } | |
825 | ||
826 | /** | |
827 | * dccp_feat_prefer - Move preferred entry to the start of array | |
828 | * Reorder the @array_len elements in @array so that @preferred_value comes | |
829 | * first. Returns >0 to indicate that @preferred_value does occur in @array. | |
830 | */ | |
831 | static u8 dccp_feat_prefer(u8 preferred_value, u8 *array, u8 array_len) | |
832 | { | |
833 | u8 i, does_occur = 0; | |
834 | ||
835 | if (array != NULL) { | |
836 | for (i = 0; i < array_len; i++) | |
837 | if (array[i] == preferred_value) { | |
838 | array[i] = array[0]; | |
839 | does_occur++; | |
840 | } | |
841 | if (does_occur) | |
842 | array[0] = preferred_value; | |
843 | } | |
844 | return does_occur; | |
845 | } | |
846 | ||
847 | /** | |
848 | * dccp_feat_reconcile - Reconcile SP preference lists | |
849 | * @fval: SP list to reconcile into | |
850 | * @arr: received SP preference list | |
851 | * @len: length of @arr in bytes | |
852 | * @is_server: whether this side is the server (and @fv is the server's list) | |
853 | * @reorder: whether to reorder the list in @fv after reconciling with @arr | |
854 | * When successful, > 0 is returned and the reconciled list is in @fval. | |
855 | * A value of 0 means that negotiation failed (no shared entry). | |
856 | */ | |
857 | static int dccp_feat_reconcile(dccp_feat_val *fv, u8 *arr, u8 len, | |
858 | bool is_server, bool reorder) | |
859 | { | |
860 | int rc; | |
861 | ||
862 | if (!fv->sp.vec || !arr) { | |
863 | DCCP_CRIT("NULL feature value or array"); | |
864 | return 0; | |
865 | } | |
866 | ||
867 | if (is_server) | |
868 | rc = dccp_feat_preflist_match(fv->sp.vec, fv->sp.len, arr, len); | |
869 | else | |
870 | rc = dccp_feat_preflist_match(arr, len, fv->sp.vec, fv->sp.len); | |
871 | ||
872 | if (!reorder) | |
873 | return rc; | |
874 | if (rc < 0) | |
875 | return 0; | |
876 | ||
877 | /* | |
878 | * Reorder list: used for activating features and in dccp_insert_fn_opt. | |
879 | */ | |
880 | return dccp_feat_prefer(rc, fv->sp.vec, fv->sp.len); | |
881 | } | |
882 | ||
e77b8363 GR |
883 | /** |
884 | * dccp_feat_change_recv - Process incoming ChangeL/R options | |
885 | * @fn: feature-negotiation list to update | |
886 | * @is_mandatory: whether the Change was preceded by a Mandatory option | |
887 | * @opt: %DCCPO_CHANGE_L or %DCCPO_CHANGE_R | |
888 | * @feat: one of %dccp_feature_numbers | |
889 | * @val: NN value or SP value/preference list | |
890 | * @len: length of @val in bytes | |
891 | * @server: whether this node is the server (1) or the client (0) | |
892 | */ | |
893 | static u8 dccp_feat_change_recv(struct list_head *fn, u8 is_mandatory, u8 opt, | |
894 | u8 feat, u8 *val, u8 len, const bool server) | |
895 | { | |
896 | u8 defval, type = dccp_feat_type(feat); | |
897 | const bool local = (opt == DCCPO_CHANGE_R); | |
898 | struct dccp_feat_entry *entry; | |
899 | dccp_feat_val fval; | |
900 | ||
901 | if (len == 0 || type == FEAT_UNKNOWN) /* 6.1 and 6.6.8 */ | |
902 | goto unknown_feature_or_value; | |
903 | ||
904 | /* | |
905 | * Negotiation of NN features: Change R is invalid, so there is no | |
906 | * simultaneous negotiation; hence we do not look up in the list. | |
907 | */ | |
908 | if (type == FEAT_NN) { | |
909 | if (local || len > sizeof(fval.nn)) | |
910 | goto unknown_feature_or_value; | |
911 | ||
912 | /* 6.3.2: "The feature remote MUST accept any valid value..." */ | |
913 | fval.nn = dccp_decode_value_var(val, len); | |
914 | if (!dccp_feat_is_valid_nn_val(feat, fval.nn)) | |
915 | goto unknown_feature_or_value; | |
916 | ||
917 | return dccp_feat_push_confirm(fn, feat, local, &fval); | |
918 | } | |
919 | ||
920 | /* | |
921 | * Unidirectional/simultaneous negotiation of SP features (6.3.1) | |
922 | */ | |
923 | entry = dccp_feat_list_lookup(fn, feat, local); | |
924 | if (entry == NULL) { | |
925 | /* | |
926 | * No particular preferences have been registered. We deal with | |
927 | * this situation by assuming that all valid values are equally | |
928 | * acceptable, and apply the following checks: | |
929 | * - if the peer's list is a singleton, we accept a valid value; | |
930 | * - if we are the server, we first try to see if the peer (the | |
931 | * client) advertises the default value. If yes, we use it, | |
932 | * otherwise we accept the preferred value; | |
933 | * - else if we are the client, we use the first list element. | |
934 | */ | |
935 | if (dccp_feat_clone_sp_val(&fval, val, 1)) | |
936 | return DCCP_RESET_CODE_TOO_BUSY; | |
937 | ||
938 | if (len > 1 && server) { | |
939 | defval = dccp_feat_default_value(feat); | |
940 | if (dccp_feat_preflist_match(&defval, 1, val, len) > -1) | |
941 | fval.sp.vec[0] = defval; | |
942 | } else if (!dccp_feat_is_valid_sp_val(feat, fval.sp.vec[0])) { | |
943 | kfree(fval.sp.vec); | |
944 | goto unknown_feature_or_value; | |
945 | } | |
946 | ||
947 | /* Treat unsupported CCIDs like invalid values */ | |
948 | if (feat == DCCPF_CCID && !ccid_support_check(fval.sp.vec, 1)) { | |
949 | kfree(fval.sp.vec); | |
950 | goto not_valid_or_not_known; | |
951 | } | |
952 | ||
953 | return dccp_feat_push_confirm(fn, feat, local, &fval); | |
954 | ||
955 | } else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */ | |
956 | return 0; | |
957 | } | |
958 | ||
959 | if (dccp_feat_reconcile(&entry->val, val, len, server, true)) { | |
960 | entry->empty_confirm = 0; | |
961 | } else if (is_mandatory) { | |
962 | return DCCP_RESET_CODE_MANDATORY_ERROR; | |
963 | } else if (entry->state == FEAT_INITIALISING) { | |
964 | /* | |
965 | * Failed simultaneous negotiation (server only): try to `save' | |
966 | * the connection by checking whether entry contains the default | |
967 | * value for @feat. If yes, send an empty Confirm to signal that | |
968 | * the received Change was not understood - which implies using | |
969 | * the default value. | |
970 | * If this also fails, we use Reset as the last resort. | |
971 | */ | |
972 | WARN_ON(!server); | |
973 | defval = dccp_feat_default_value(feat); | |
974 | if (!dccp_feat_reconcile(&entry->val, &defval, 1, server, true)) | |
975 | return DCCP_RESET_CODE_OPTION_ERROR; | |
976 | entry->empty_confirm = 1; | |
977 | } | |
978 | entry->needs_confirm = 1; | |
979 | entry->needs_mandatory = 0; | |
980 | entry->state = FEAT_STABLE; | |
981 | return 0; | |
982 | ||
983 | unknown_feature_or_value: | |
984 | if (!is_mandatory) | |
985 | return dccp_push_empty_confirm(fn, feat, local); | |
986 | ||
987 | not_valid_or_not_known: | |
988 | return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR | |
989 | : DCCP_RESET_CODE_OPTION_ERROR; | |
990 | } | |
991 | ||
b1ad0042 GR |
992 | /** |
993 | * dccp_feat_confirm_recv - Process received Confirm options | |
994 | * @fn: feature-negotiation list to update | |
995 | * @is_mandatory: whether @opt was preceded by a Mandatory option | |
996 | * @opt: %DCCPO_CONFIRM_L or %DCCPO_CONFIRM_R | |
997 | * @feat: one of %dccp_feature_numbers | |
998 | * @val: NN value or SP value/preference list | |
999 | * @len: length of @val in bytes | |
1000 | * @server: whether this node is server (1) or client (0) | |
1001 | */ | |
1002 | static u8 dccp_feat_confirm_recv(struct list_head *fn, u8 is_mandatory, u8 opt, | |
1003 | u8 feat, u8 *val, u8 len, const bool server) | |
1004 | { | |
1005 | u8 *plist, plen, type = dccp_feat_type(feat); | |
1006 | const bool local = (opt == DCCPO_CONFIRM_R); | |
1007 | struct dccp_feat_entry *entry = dccp_feat_list_lookup(fn, feat, local); | |
1008 | ||
1009 | if (entry == NULL) { /* nothing queued: ignore or handle error */ | |
1010 | if (is_mandatory && type == FEAT_UNKNOWN) | |
1011 | return DCCP_RESET_CODE_MANDATORY_ERROR; | |
1012 | ||
1013 | if (!local && type == FEAT_NN) /* 6.3.2 */ | |
1014 | goto confirmation_failed; | |
1015 | return 0; | |
1016 | } | |
1017 | ||
1018 | if (entry->state != FEAT_CHANGING) /* 6.6.2 */ | |
1019 | return 0; | |
1020 | ||
1021 | if (len == 0) { | |
1022 | if (dccp_feat_must_be_understood(feat)) /* 6.6.7 */ | |
1023 | goto confirmation_failed; | |
1024 | /* | |
1025 | * Empty Confirm during connection setup: this means reverting | |
1026 | * to the `old' value, which in this case is the default. Since | |
1027 | * we handle default values automatically when no other values | |
1028 | * have been set, we revert to the old value by removing this | |
1029 | * entry from the list. | |
1030 | */ | |
1031 | dccp_feat_list_pop(entry); | |
1032 | return 0; | |
1033 | } | |
1034 | ||
1035 | if (type == FEAT_NN) { | |
1036 | if (len > sizeof(entry->val.nn)) | |
1037 | goto confirmation_failed; | |
1038 | ||
1039 | if (entry->val.nn == dccp_decode_value_var(val, len)) | |
1040 | goto confirmation_succeeded; | |
1041 | ||
1042 | DCCP_WARN("Bogus Confirm for non-existing value\n"); | |
1043 | goto confirmation_failed; | |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * Parsing SP Confirms: the first element of @val is the preferred | |
1048 | * SP value which the peer confirms, the remainder depends on @len. | |
1049 | * Note that only the confirmed value need to be a valid SP value. | |
1050 | */ | |
1051 | if (!dccp_feat_is_valid_sp_val(feat, *val)) | |
1052 | goto confirmation_failed; | |
1053 | ||
1054 | if (len == 1) { /* peer didn't supply a preference list */ | |
1055 | plist = val; | |
1056 | plen = len; | |
1057 | } else { /* preferred value + preference list */ | |
1058 | plist = val + 1; | |
1059 | plen = len - 1; | |
1060 | } | |
1061 | ||
1062 | /* Check whether the peer got the reconciliation right (6.6.8) */ | |
1063 | if (dccp_feat_reconcile(&entry->val, plist, plen, server, 0) != *val) { | |
1064 | DCCP_WARN("Confirm selected the wrong value %u\n", *val); | |
1065 | return DCCP_RESET_CODE_OPTION_ERROR; | |
1066 | } | |
1067 | entry->val.sp.vec[0] = *val; | |
1068 | ||
1069 | confirmation_succeeded: | |
1070 | entry->state = FEAT_STABLE; | |
1071 | return 0; | |
1072 | ||
1073 | confirmation_failed: | |
1074 | DCCP_WARN("Confirmation failed\n"); | |
1075 | return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR | |
1076 | : DCCP_RESET_CODE_OPTION_ERROR; | |
1077 | } | |
1078 | ||
e77b8363 GR |
1079 | /** |
1080 | * dccp_feat_parse_options - Process Feature-Negotiation Options | |
1081 | * @sk: for general use and used by the client during connection setup | |
1082 | * @dreq: used by the server during connection setup | |
1083 | * @mandatory: whether @opt was preceded by a Mandatory option | |
1084 | * @opt: %DCCPO_CHANGE_L | %DCCPO_CHANGE_R | %DCCPO_CONFIRM_L | %DCCPO_CONFIRM_R | |
1085 | * @feat: one of %dccp_feature_numbers | |
1086 | * @val: value contents of @opt | |
1087 | * @len: length of @val in bytes | |
1088 | * Returns 0 on success, a Reset code for ending the connection otherwise. | |
1089 | */ | |
1090 | int dccp_feat_parse_options(struct sock *sk, struct dccp_request_sock *dreq, | |
1091 | u8 mandatory, u8 opt, u8 feat, u8 *val, u8 len) | |
1092 | { | |
1093 | struct dccp_sock *dp = dccp_sk(sk); | |
1094 | struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg; | |
1095 | bool server = false; | |
1096 | ||
1097 | switch (sk->sk_state) { | |
1098 | /* | |
1099 | * Negotiation during connection setup | |
1100 | */ | |
1101 | case DCCP_LISTEN: | |
1102 | server = true; /* fall through */ | |
1103 | case DCCP_REQUESTING: | |
1104 | switch (opt) { | |
1105 | case DCCPO_CHANGE_L: | |
1106 | case DCCPO_CHANGE_R: | |
1107 | return dccp_feat_change_recv(fn, mandatory, opt, feat, | |
1108 | val, len, server); | |
b1ad0042 GR |
1109 | case DCCPO_CONFIRM_R: |
1110 | case DCCPO_CONFIRM_L: | |
1111 | return dccp_feat_confirm_recv(fn, mandatory, opt, feat, | |
1112 | val, len, server); | |
e77b8363 GR |
1113 | } |
1114 | } | |
1115 | return 0; /* ignore FN options in all other states */ | |
1116 | } | |
1117 | ||
f90f92ee GR |
1118 | /** |
1119 | * dccp_feat_init - Seed feature negotiation with host-specific defaults | |
1120 | * This initialises global defaults, depending on the value of the sysctls. | |
1121 | * These can later be overridden by registering changes via setsockopt calls. | |
1122 | * The last link in the chain is finalise_settings, to make sure that between | |
1123 | * here and the start of actual feature negotiation no inconsistencies enter. | |
1124 | * | |
1125 | * All features not appearing below use either defaults or are otherwise | |
1126 | * later adjusted through dccp_feat_finalise_settings(). | |
1127 | */ | |
e8ef967a | 1128 | int dccp_feat_init(struct sock *sk) |
afe00251 | 1129 | { |
f90f92ee GR |
1130 | struct list_head *fn = &dccp_sk(sk)->dccps_featneg; |
1131 | u8 on = 1, off = 0; | |
afe00251 | 1132 | int rc; |
f90f92ee GR |
1133 | struct { |
1134 | u8 *val; | |
1135 | u8 len; | |
1136 | } tx, rx; | |
1137 | ||
1138 | /* Non-negotiable (NN) features */ | |
1139 | rc = __feat_register_nn(fn, DCCPF_SEQUENCE_WINDOW, 0, | |
1140 | sysctl_dccp_feat_sequence_window); | |
1141 | if (rc) | |
1142 | return rc; | |
1143 | ||
1144 | /* Server-priority (SP) features */ | |
1145 | ||
1146 | /* Advertise that short seqnos are not supported (7.6.1) */ | |
1147 | rc = __feat_register_sp(fn, DCCPF_SHORT_SEQNOS, true, true, &off, 1); | |
1148 | if (rc) | |
1149 | return rc; | |
afe00251 | 1150 | |
f90f92ee GR |
1151 | /* RFC 4340 12.1: "If a DCCP is not ECN capable, ..." */ |
1152 | rc = __feat_register_sp(fn, DCCPF_ECN_INCAPABLE, true, true, &on, 1); | |
1153 | if (rc) | |
1154 | return rc; | |
1155 | ||
1156 | /* | |
1157 | * We advertise the available list of CCIDs and reorder according to | |
1158 | * preferences, to avoid failure resulting from negotiating different | |
1159 | * singleton values (which always leads to failure). | |
1160 | * These settings can still (later) be overridden via sockopts. | |
1161 | */ | |
1162 | if (ccid_get_builtin_ccids(&tx.val, &tx.len) || | |
1163 | ccid_get_builtin_ccids(&rx.val, &rx.len)) | |
1164 | return -ENOBUFS; | |
afe00251 | 1165 | |
f90f92ee GR |
1166 | if (!dccp_feat_prefer(sysctl_dccp_feat_tx_ccid, tx.val, tx.len) || |
1167 | !dccp_feat_prefer(sysctl_dccp_feat_rx_ccid, rx.val, rx.len)) | |
1168 | goto free_ccid_lists; | |
1169 | ||
1170 | rc = __feat_register_sp(fn, DCCPF_CCID, true, false, tx.val, tx.len); | |
1171 | if (rc) | |
1172 | goto free_ccid_lists; | |
1173 | ||
1174 | rc = __feat_register_sp(fn, DCCPF_CCID, false, false, rx.val, rx.len); | |
1175 | ||
1176 | free_ccid_lists: | |
1177 | kfree(tx.val); | |
1178 | kfree(rx.val); | |
afe00251 AB |
1179 | return rc; |
1180 | } | |
1181 | ||
422d9cdc GR |
1182 | int dccp_feat_activate_values(struct sock *sk, struct list_head *fn_list) |
1183 | { | |
1184 | struct dccp_sock *dp = dccp_sk(sk); | |
1185 | struct dccp_feat_entry *cur, *next; | |
1186 | int idx; | |
1187 | dccp_feat_val *fvals[DCCP_FEAT_SUPPORTED_MAX][2] = { | |
1188 | [0 ... DCCP_FEAT_SUPPORTED_MAX-1] = { NULL, NULL } | |
1189 | }; | |
1190 | ||
1191 | list_for_each_entry(cur, fn_list, node) { | |
1192 | /* | |
1193 | * An empty Confirm means that either an unknown feature type | |
1194 | * or an invalid value was present. In the first case there is | |
1195 | * nothing to activate, in the other the default value is used. | |
1196 | */ | |
1197 | if (cur->empty_confirm) | |
1198 | continue; | |
1199 | ||
1200 | idx = dccp_feat_index(cur->feat_num); | |
1201 | if (idx < 0) { | |
1202 | DCCP_BUG("Unknown feature %u", cur->feat_num); | |
1203 | goto activation_failed; | |
1204 | } | |
1205 | if (cur->state != FEAT_STABLE) { | |
1206 | DCCP_CRIT("Negotiation of %s %u failed in state %u", | |
1207 | cur->is_local ? "local" : "remote", | |
1208 | cur->feat_num, cur->state); | |
1209 | goto activation_failed; | |
1210 | } | |
1211 | fvals[idx][cur->is_local] = &cur->val; | |
1212 | } | |
1213 | ||
1214 | /* | |
1215 | * Activate in decreasing order of index, so that the CCIDs are always | |
1216 | * activated as the last feature. This avoids the case where a CCID | |
1217 | * relies on the initialisation of one or more features that it depends | |
1218 | * on (e.g. Send NDP Count, Send Ack Vector, and Ack Ratio features). | |
1219 | */ | |
1220 | for (idx = DCCP_FEAT_SUPPORTED_MAX; --idx >= 0;) | |
1221 | if (__dccp_feat_activate(sk, idx, 0, fvals[idx][0]) || | |
1222 | __dccp_feat_activate(sk, idx, 1, fvals[idx][1])) { | |
1223 | DCCP_CRIT("Could not activate %d", idx); | |
1224 | goto activation_failed; | |
1225 | } | |
1226 | ||
1227 | /* Clean up Change options which have been confirmed already */ | |
1228 | list_for_each_entry_safe(cur, next, fn_list, node) | |
1229 | if (!cur->needs_confirm) | |
1230 | dccp_feat_list_pop(cur); | |
1231 | ||
1232 | dccp_pr_debug("Activation OK\n"); | |
1233 | return 0; | |
1234 | ||
1235 | activation_failed: | |
1236 | /* | |
1237 | * We clean up everything that may have been allocated, since | |
1238 | * it is difficult to track at which stage negotiation failed. | |
1239 | * This is ok, since all allocation functions below are robust | |
1240 | * against NULL arguments. | |
1241 | */ | |
1242 | ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); | |
1243 | ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); | |
1244 | dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL; | |
1245 | dccp_ackvec_free(dp->dccps_hc_rx_ackvec); | |
1246 | dp->dccps_hc_rx_ackvec = NULL; | |
1247 | return -1; | |
1248 | } | |
1249 | ||
c02fdc0e GR |
1250 | #ifdef CONFIG_IP_DCCP_DEBUG |
1251 | const char *dccp_feat_typename(const u8 type) | |
1252 | { | |
1253 | switch(type) { | |
1254 | case DCCPO_CHANGE_L: return("ChangeL"); | |
1255 | case DCCPO_CONFIRM_L: return("ConfirmL"); | |
1256 | case DCCPO_CHANGE_R: return("ChangeR"); | |
1257 | case DCCPO_CONFIRM_R: return("ConfirmR"); | |
1258 | /* the following case must not appear in feature negotation */ | |
8109b02b | 1259 | default: dccp_pr_debug("unknown type %d [BUG!]\n", type); |
c02fdc0e GR |
1260 | } |
1261 | return NULL; | |
1262 | } | |
1263 | ||
c02fdc0e GR |
1264 | const char *dccp_feat_name(const u8 feat) |
1265 | { | |
1266 | static const char *feature_names[] = { | |
1267 | [DCCPF_RESERVED] = "Reserved", | |
1268 | [DCCPF_CCID] = "CCID", | |
1269 | [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos", | |
1270 | [DCCPF_SEQUENCE_WINDOW] = "Sequence Window", | |
1271 | [DCCPF_ECN_INCAPABLE] = "ECN Incapable", | |
1272 | [DCCPF_ACK_RATIO] = "Ack Ratio", | |
1273 | [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector", | |
1274 | [DCCPF_SEND_NDP_COUNT] = "Send NDP Count", | |
1275 | [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage", | |
1276 | [DCCPF_DATA_CHECKSUM] = "Send Data Checksum", | |
1277 | }; | |
dd6303df GR |
1278 | if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC) |
1279 | return feature_names[DCCPF_RESERVED]; | |
1280 | ||
7d43d1a0 GR |
1281 | if (feat == DCCPF_SEND_LEV_RATE) |
1282 | return "Send Loss Event Rate"; | |
c02fdc0e GR |
1283 | if (feat >= DCCPF_MIN_CCID_SPECIFIC) |
1284 | return "CCID-specific"; | |
1285 | ||
c02fdc0e GR |
1286 | return feature_names[feat]; |
1287 | } | |
c02fdc0e | 1288 | #endif /* CONFIG_IP_DCCP_DEBUG */ |