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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * net/dccp/feat.c | |
4 | * | |
5 | * Feature negotiation for the DCCP protocol (RFC 4340, section 6) | |
6 | * | |
7 | * Copyright (c) 2008 Gerrit Renker <gerrit@erg.abdn.ac.uk> | |
8 | * Rewrote from scratch, some bits from earlier code by | |
9 | * Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk> | |
10 | * | |
11 | * ASSUMPTIONS | |
12 | * ----------- | |
13 | * o Feature negotiation is coordinated with connection setup (as in TCP), wild | |
14 | * changes of parameters of an established connection are not supported. | |
15 | * o Changing non-negotiable (NN) values is supported in state OPEN/PARTOPEN. | |
16 | * o All currently known SP features have 1-byte quantities. If in the future | |
17 | * extensions of RFCs 4340..42 define features with item lengths larger than | |
18 | * one byte, a feature-specific extension of the code will be required. | |
19 | */ | |
20 | #include <linux/module.h> | |
21 | #include <linux/slab.h> | |
22 | #include "ccid.h" | |
23 | #include "feat.h" | |
24 | ||
25 | /* feature-specific sysctls - initialised to the defaults from RFC 4340, 6.4 */ | |
26 | unsigned long sysctl_dccp_sequence_window __read_mostly = 100; | |
27 | int sysctl_dccp_rx_ccid __read_mostly = 2, | |
28 | sysctl_dccp_tx_ccid __read_mostly = 2; | |
29 | ||
30 | /* | |
31 | * Feature activation handlers. | |
32 | * | |
33 | * These all use an u64 argument, to provide enough room for NN/SP features. At | |
34 | * this stage the negotiated values have been checked to be within their range. | |
35 | */ | |
36 | static int dccp_hdlr_ccid(struct sock *sk, u64 ccid, bool rx) | |
37 | { | |
38 | struct dccp_sock *dp = dccp_sk(sk); | |
39 | struct ccid *new_ccid = ccid_new(ccid, sk, rx); | |
40 | ||
41 | if (new_ccid == NULL) | |
42 | return -ENOMEM; | |
43 | ||
44 | if (rx) { | |
45 | ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); | |
46 | dp->dccps_hc_rx_ccid = new_ccid; | |
47 | } else { | |
48 | ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); | |
49 | dp->dccps_hc_tx_ccid = new_ccid; | |
50 | } | |
51 | return 0; | |
52 | } | |
53 | ||
54 | static int dccp_hdlr_seq_win(struct sock *sk, u64 seq_win, bool rx) | |
55 | { | |
56 | struct dccp_sock *dp = dccp_sk(sk); | |
57 | ||
58 | if (rx) { | |
59 | dp->dccps_r_seq_win = seq_win; | |
60 | /* propagate changes to update SWL/SWH */ | |
61 | dccp_update_gsr(sk, dp->dccps_gsr); | |
62 | } else { | |
63 | dp->dccps_l_seq_win = seq_win; | |
64 | /* propagate changes to update AWL */ | |
65 | dccp_update_gss(sk, dp->dccps_gss); | |
66 | } | |
67 | return 0; | |
68 | } | |
69 | ||
70 | static int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx) | |
71 | { | |
72 | if (rx) | |
73 | dccp_sk(sk)->dccps_r_ack_ratio = ratio; | |
74 | else | |
75 | dccp_sk(sk)->dccps_l_ack_ratio = ratio; | |
76 | return 0; | |
77 | } | |
78 | ||
79 | static int dccp_hdlr_ackvec(struct sock *sk, u64 enable, bool rx) | |
80 | { | |
81 | struct dccp_sock *dp = dccp_sk(sk); | |
82 | ||
83 | if (rx) { | |
84 | if (enable && dp->dccps_hc_rx_ackvec == NULL) { | |
85 | dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(gfp_any()); | |
86 | if (dp->dccps_hc_rx_ackvec == NULL) | |
87 | return -ENOMEM; | |
88 | } else if (!enable) { | |
89 | dccp_ackvec_free(dp->dccps_hc_rx_ackvec); | |
90 | dp->dccps_hc_rx_ackvec = NULL; | |
91 | } | |
92 | } | |
93 | return 0; | |
94 | } | |
95 | ||
96 | static int dccp_hdlr_ndp(struct sock *sk, u64 enable, bool rx) | |
97 | { | |
98 | if (!rx) | |
99 | dccp_sk(sk)->dccps_send_ndp_count = (enable > 0); | |
100 | return 0; | |
101 | } | |
102 | ||
103 | /* | |
104 | * Minimum Checksum Coverage is located at the RX side (9.2.1). This means that | |
105 | * `rx' holds when the sending peer informs about his partial coverage via a | |
106 | * ChangeR() option. In the other case, we are the sender and the receiver | |
107 | * announces its coverage via ChangeL() options. The policy here is to honour | |
108 | * such communication by enabling the corresponding partial coverage - but only | |
109 | * if it has not been set manually before; the warning here means that all | |
110 | * packets will be dropped. | |
111 | */ | |
112 | static int dccp_hdlr_min_cscov(struct sock *sk, u64 cscov, bool rx) | |
113 | { | |
114 | struct dccp_sock *dp = dccp_sk(sk); | |
115 | ||
116 | if (rx) | |
117 | dp->dccps_pcrlen = cscov; | |
118 | else { | |
119 | if (dp->dccps_pcslen == 0) | |
120 | dp->dccps_pcslen = cscov; | |
121 | else if (cscov > dp->dccps_pcslen) | |
122 | DCCP_WARN("CsCov %u too small, peer requires >= %u\n", | |
123 | dp->dccps_pcslen, (u8)cscov); | |
124 | } | |
125 | return 0; | |
126 | } | |
127 | ||
128 | static const struct { | |
129 | u8 feat_num; /* DCCPF_xxx */ | |
130 | enum dccp_feat_type rxtx; /* RX or TX */ | |
131 | enum dccp_feat_type reconciliation; /* SP or NN */ | |
132 | u8 default_value; /* as in 6.4 */ | |
133 | int (*activation_hdlr)(struct sock *sk, u64 val, bool rx); | |
134 | /* | |
135 | * Lookup table for location and type of features (from RFC 4340/4342) | |
136 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
137 | * | Feature | Location | Reconc. | Initial | Section | | |
138 | * | | RX | TX | SP | NN | Value | Reference | | |
139 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
140 | * | DCCPF_CCID | | X | X | | 2 | 10 | | |
141 | * | DCCPF_SHORT_SEQNOS | | X | X | | 0 | 7.6.1 | | |
142 | * | DCCPF_SEQUENCE_WINDOW | | X | | X | 100 | 7.5.2 | | |
143 | * | DCCPF_ECN_INCAPABLE | X | | X | | 0 | 12.1 | | |
144 | * | DCCPF_ACK_RATIO | | X | | X | 2 | 11.3 | | |
145 | * | DCCPF_SEND_ACK_VECTOR | X | | X | | 0 | 11.5 | | |
146 | * | DCCPF_SEND_NDP_COUNT | | X | X | | 0 | 7.7.2 | | |
147 | * | DCCPF_MIN_CSUM_COVER | X | | X | | 0 | 9.2.1 | | |
148 | * | DCCPF_DATA_CHECKSUM | X | | X | | 0 | 9.3.1 | | |
149 | * | DCCPF_SEND_LEV_RATE | X | | X | | 0 | 4342/8.4 | | |
150 | * +--------------------------+----+-----+----+----+---------+-----------+ | |
151 | */ | |
152 | } dccp_feat_table[] = { | |
153 | { DCCPF_CCID, FEAT_AT_TX, FEAT_SP, 2, dccp_hdlr_ccid }, | |
154 | { DCCPF_SHORT_SEQNOS, FEAT_AT_TX, FEAT_SP, 0, NULL }, | |
155 | { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100, dccp_hdlr_seq_win }, | |
156 | { DCCPF_ECN_INCAPABLE, FEAT_AT_RX, FEAT_SP, 0, NULL }, | |
157 | { DCCPF_ACK_RATIO, FEAT_AT_TX, FEAT_NN, 2, dccp_hdlr_ack_ratio}, | |
158 | { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_ackvec }, | |
159 | { DCCPF_SEND_NDP_COUNT, FEAT_AT_TX, FEAT_SP, 0, dccp_hdlr_ndp }, | |
160 | { DCCPF_MIN_CSUM_COVER, FEAT_AT_RX, FEAT_SP, 0, dccp_hdlr_min_cscov}, | |
161 | { DCCPF_DATA_CHECKSUM, FEAT_AT_RX, FEAT_SP, 0, NULL }, | |
162 | { DCCPF_SEND_LEV_RATE, FEAT_AT_RX, FEAT_SP, 0, NULL }, | |
163 | }; | |
164 | #define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table) | |
165 | ||
166 | /** | |
167 | * dccp_feat_index - Hash function to map feature number into array position | |
168 | * Returns consecutive array index or -1 if the feature is not understood. | |
169 | */ | |
170 | static int dccp_feat_index(u8 feat_num) | |
171 | { | |
172 | /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */ | |
173 | if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM) | |
174 | return feat_num - 1; | |
175 | ||
176 | /* | |
177 | * Other features: add cases for new feature types here after adding | |
178 | * them to the above table. | |
179 | */ | |
180 | switch (feat_num) { | |
181 | case DCCPF_SEND_LEV_RATE: | |
182 | return DCCP_FEAT_SUPPORTED_MAX - 1; | |
183 | } | |
184 | return -1; | |
185 | } | |
186 | ||
187 | static u8 dccp_feat_type(u8 feat_num) | |
188 | { | |
189 | int idx = dccp_feat_index(feat_num); | |
190 | ||
191 | if (idx < 0) | |
192 | return FEAT_UNKNOWN; | |
193 | return dccp_feat_table[idx].reconciliation; | |
194 | } | |
195 | ||
196 | static int dccp_feat_default_value(u8 feat_num) | |
197 | { | |
198 | int idx = dccp_feat_index(feat_num); | |
199 | /* | |
200 | * There are no default values for unknown features, so encountering a | |
201 | * negative index here indicates a serious problem somewhere else. | |
202 | */ | |
203 | DCCP_BUG_ON(idx < 0); | |
204 | ||
205 | return idx < 0 ? 0 : dccp_feat_table[idx].default_value; | |
206 | } | |
207 | ||
208 | /* | |
209 | * Debugging and verbose-printing section | |
210 | */ | |
211 | static const char *dccp_feat_fname(const u8 feat) | |
212 | { | |
213 | static const char *const feature_names[] = { | |
214 | [DCCPF_RESERVED] = "Reserved", | |
215 | [DCCPF_CCID] = "CCID", | |
216 | [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos", | |
217 | [DCCPF_SEQUENCE_WINDOW] = "Sequence Window", | |
218 | [DCCPF_ECN_INCAPABLE] = "ECN Incapable", | |
219 | [DCCPF_ACK_RATIO] = "Ack Ratio", | |
220 | [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector", | |
221 | [DCCPF_SEND_NDP_COUNT] = "Send NDP Count", | |
222 | [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage", | |
223 | [DCCPF_DATA_CHECKSUM] = "Send Data Checksum", | |
224 | }; | |
225 | if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC) | |
226 | return feature_names[DCCPF_RESERVED]; | |
227 | ||
228 | if (feat == DCCPF_SEND_LEV_RATE) | |
229 | return "Send Loss Event Rate"; | |
230 | if (feat >= DCCPF_MIN_CCID_SPECIFIC) | |
231 | return "CCID-specific"; | |
232 | ||
233 | return feature_names[feat]; | |
234 | } | |
235 | ||
236 | static const char *const dccp_feat_sname[] = { | |
237 | "DEFAULT", "INITIALISING", "CHANGING", "UNSTABLE", "STABLE", | |
238 | }; | |
239 | ||
240 | #ifdef CONFIG_IP_DCCP_DEBUG | |
241 | static const char *dccp_feat_oname(const u8 opt) | |
242 | { | |
243 | switch (opt) { | |
244 | case DCCPO_CHANGE_L: return "Change_L"; | |
245 | case DCCPO_CONFIRM_L: return "Confirm_L"; | |
246 | case DCCPO_CHANGE_R: return "Change_R"; | |
247 | case DCCPO_CONFIRM_R: return "Confirm_R"; | |
248 | } | |
249 | return NULL; | |
250 | } | |
251 | ||
252 | static void dccp_feat_printval(u8 feat_num, dccp_feat_val const *val) | |
253 | { | |
254 | u8 i, type = dccp_feat_type(feat_num); | |
255 | ||
256 | if (val == NULL || (type == FEAT_SP && val->sp.vec == NULL)) | |
257 | dccp_pr_debug_cat("(NULL)"); | |
258 | else if (type == FEAT_SP) | |
259 | for (i = 0; i < val->sp.len; i++) | |
260 | dccp_pr_debug_cat("%s%u", i ? " " : "", val->sp.vec[i]); | |
261 | else if (type == FEAT_NN) | |
262 | dccp_pr_debug_cat("%llu", (unsigned long long)val->nn); | |
263 | else | |
264 | dccp_pr_debug_cat("unknown type %u", type); | |
265 | } | |
266 | ||
267 | static void dccp_feat_printvals(u8 feat_num, u8 *list, u8 len) | |
268 | { | |
269 | u8 type = dccp_feat_type(feat_num); | |
270 | dccp_feat_val fval = { .sp.vec = list, .sp.len = len }; | |
271 | ||
272 | if (type == FEAT_NN) | |
273 | fval.nn = dccp_decode_value_var(list, len); | |
274 | dccp_feat_printval(feat_num, &fval); | |
275 | } | |
276 | ||
277 | static void dccp_feat_print_entry(struct dccp_feat_entry const *entry) | |
278 | { | |
279 | dccp_debug(" * %s %s = ", entry->is_local ? "local" : "remote", | |
280 | dccp_feat_fname(entry->feat_num)); | |
281 | dccp_feat_printval(entry->feat_num, &entry->val); | |
282 | dccp_pr_debug_cat(", state=%s %s\n", dccp_feat_sname[entry->state], | |
283 | entry->needs_confirm ? "(Confirm pending)" : ""); | |
284 | } | |
285 | ||
286 | #define dccp_feat_print_opt(opt, feat, val, len, mandatory) do { \ | |
287 | dccp_pr_debug("%s(%s, ", dccp_feat_oname(opt), dccp_feat_fname(feat));\ | |
288 | dccp_feat_printvals(feat, val, len); \ | |
289 | dccp_pr_debug_cat(") %s\n", mandatory ? "!" : ""); } while (0) | |
290 | ||
291 | #define dccp_feat_print_fnlist(fn_list) { \ | |
292 | const struct dccp_feat_entry *___entry; \ | |
293 | \ | |
294 | dccp_pr_debug("List Dump:\n"); \ | |
295 | list_for_each_entry(___entry, fn_list, node) \ | |
296 | dccp_feat_print_entry(___entry); \ | |
297 | } | |
298 | #else /* ! CONFIG_IP_DCCP_DEBUG */ | |
299 | #define dccp_feat_print_opt(opt, feat, val, len, mandatory) | |
300 | #define dccp_feat_print_fnlist(fn_list) | |
301 | #endif | |
302 | ||
303 | static int __dccp_feat_activate(struct sock *sk, const int idx, | |
304 | const bool is_local, dccp_feat_val const *fval) | |
305 | { | |
306 | bool rx; | |
307 | u64 val; | |
308 | ||
309 | if (idx < 0 || idx >= DCCP_FEAT_SUPPORTED_MAX) | |
310 | return -1; | |
311 | if (dccp_feat_table[idx].activation_hdlr == NULL) | |
312 | return 0; | |
313 | ||
314 | if (fval == NULL) { | |
315 | val = dccp_feat_table[idx].default_value; | |
316 | } else if (dccp_feat_table[idx].reconciliation == FEAT_SP) { | |
317 | if (fval->sp.vec == NULL) { | |
318 | /* | |
319 | * This can happen when an empty Confirm is sent | |
320 | * for an SP (i.e. known) feature. In this case | |
321 | * we would be using the default anyway. | |
322 | */ | |
323 | DCCP_CRIT("Feature #%d undefined: using default", idx); | |
324 | val = dccp_feat_table[idx].default_value; | |
325 | } else { | |
326 | val = fval->sp.vec[0]; | |
327 | } | |
328 | } else { | |
329 | val = fval->nn; | |
330 | } | |
331 | ||
332 | /* Location is RX if this is a local-RX or remote-TX feature */ | |
333 | rx = (is_local == (dccp_feat_table[idx].rxtx == FEAT_AT_RX)); | |
334 | ||
335 | dccp_debug(" -> activating %s %s, %sval=%llu\n", rx ? "RX" : "TX", | |
336 | dccp_feat_fname(dccp_feat_table[idx].feat_num), | |
337 | fval ? "" : "default ", (unsigned long long)val); | |
338 | ||
339 | return dccp_feat_table[idx].activation_hdlr(sk, val, rx); | |
340 | } | |
341 | ||
342 | /** | |
343 | * dccp_feat_activate - Activate feature value on socket | |
344 | * @sk: fully connected DCCP socket (after handshake is complete) | |
345 | * @feat_num: feature to activate, one of %dccp_feature_numbers | |
346 | * @local: whether local (1) or remote (0) @feat_num is meant | |
347 | * @fval: the value (SP or NN) to activate, or NULL to use the default value | |
348 | * | |
349 | * For general use this function is preferable over __dccp_feat_activate(). | |
350 | */ | |
351 | static int dccp_feat_activate(struct sock *sk, u8 feat_num, bool local, | |
352 | dccp_feat_val const *fval) | |
353 | { | |
354 | return __dccp_feat_activate(sk, dccp_feat_index(feat_num), local, fval); | |
355 | } | |
356 | ||
357 | /* Test for "Req'd" feature (RFC 4340, 6.4) */ | |
358 | static inline int dccp_feat_must_be_understood(u8 feat_num) | |
359 | { | |
360 | return feat_num == DCCPF_CCID || feat_num == DCCPF_SHORT_SEQNOS || | |
361 | feat_num == DCCPF_SEQUENCE_WINDOW; | |
362 | } | |
363 | ||
364 | /* copy constructor, fval must not already contain allocated memory */ | |
365 | static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len) | |
366 | { | |
367 | fval->sp.len = len; | |
368 | if (fval->sp.len > 0) { | |
369 | fval->sp.vec = kmemdup(val, len, gfp_any()); | |
370 | if (fval->sp.vec == NULL) { | |
371 | fval->sp.len = 0; | |
372 | return -ENOBUFS; | |
373 | } | |
374 | } | |
375 | return 0; | |
376 | } | |
377 | ||
378 | static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val) | |
379 | { | |
380 | if (unlikely(val == NULL)) | |
381 | return; | |
382 | if (dccp_feat_type(feat_num) == FEAT_SP) | |
383 | kfree(val->sp.vec); | |
384 | memset(val, 0, sizeof(*val)); | |
385 | } | |
386 | ||
387 | static struct dccp_feat_entry * | |
388 | dccp_feat_clone_entry(struct dccp_feat_entry const *original) | |
389 | { | |
390 | struct dccp_feat_entry *new; | |
391 | u8 type = dccp_feat_type(original->feat_num); | |
392 | ||
393 | if (type == FEAT_UNKNOWN) | |
394 | return NULL; | |
395 | ||
396 | new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any()); | |
397 | if (new == NULL) | |
398 | return NULL; | |
399 | ||
400 | if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val, | |
401 | original->val.sp.vec, | |
402 | original->val.sp.len)) { | |
403 | kfree(new); | |
404 | return NULL; | |
405 | } | |
406 | return new; | |
407 | } | |
408 | ||
409 | static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry) | |
410 | { | |
411 | if (entry != NULL) { | |
412 | dccp_feat_val_destructor(entry->feat_num, &entry->val); | |
413 | kfree(entry); | |
414 | } | |
415 | } | |
416 | ||
417 | /* | |
418 | * List management functions | |
419 | * | |
420 | * Feature negotiation lists rely on and maintain the following invariants: | |
421 | * - each feat_num in the list is known, i.e. we know its type and default value | |
422 | * - each feat_num/is_local combination is unique (old entries are overwritten) | |
423 | * - SP values are always freshly allocated | |
424 | * - list is sorted in increasing order of feature number (faster lookup) | |
425 | */ | |
426 | static struct dccp_feat_entry *dccp_feat_list_lookup(struct list_head *fn_list, | |
427 | u8 feat_num, bool is_local) | |
428 | { | |
429 | struct dccp_feat_entry *entry; | |
430 | ||
431 | list_for_each_entry(entry, fn_list, node) { | |
432 | if (entry->feat_num == feat_num && entry->is_local == is_local) | |
433 | return entry; | |
434 | else if (entry->feat_num > feat_num) | |
435 | break; | |
436 | } | |
437 | return NULL; | |
438 | } | |
439 | ||
440 | /** | |
441 | * dccp_feat_entry_new - Central list update routine (called by all others) | |
442 | * @head: list to add to | |
443 | * @feat: feature number | |
444 | * @local: whether the local (1) or remote feature with number @feat is meant | |
445 | * | |
446 | * This is the only constructor and serves to ensure the above invariants. | |
447 | */ | |
448 | static struct dccp_feat_entry * | |
449 | dccp_feat_entry_new(struct list_head *head, u8 feat, bool local) | |
450 | { | |
451 | struct dccp_feat_entry *entry; | |
452 | ||
453 | list_for_each_entry(entry, head, node) | |
454 | if (entry->feat_num == feat && entry->is_local == local) { | |
455 | dccp_feat_val_destructor(entry->feat_num, &entry->val); | |
456 | return entry; | |
457 | } else if (entry->feat_num > feat) { | |
458 | head = &entry->node; | |
459 | break; | |
460 | } | |
461 | ||
462 | entry = kmalloc(sizeof(*entry), gfp_any()); | |
463 | if (entry != NULL) { | |
464 | entry->feat_num = feat; | |
465 | entry->is_local = local; | |
466 | list_add_tail(&entry->node, head); | |
467 | } | |
468 | return entry; | |
469 | } | |
470 | ||
471 | /** | |
472 | * dccp_feat_push_change - Add/overwrite a Change option in the list | |
473 | * @fn_list: feature-negotiation list to update | |
474 | * @feat: one of %dccp_feature_numbers | |
475 | * @local: whether local (1) or remote (0) @feat_num is meant | |
476 | * @mandatory: whether to use Mandatory feature negotiation options | |
477 | * @fval: pointer to NN/SP value to be inserted (will be copied) | |
478 | */ | |
479 | static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local, | |
480 | u8 mandatory, dccp_feat_val *fval) | |
481 | { | |
482 | struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); | |
483 | ||
484 | if (new == NULL) | |
485 | return -ENOMEM; | |
486 | ||
487 | new->feat_num = feat; | |
488 | new->is_local = local; | |
489 | new->state = FEAT_INITIALISING; | |
490 | new->needs_confirm = false; | |
491 | new->empty_confirm = false; | |
492 | new->val = *fval; | |
493 | new->needs_mandatory = mandatory; | |
494 | ||
495 | return 0; | |
496 | } | |
497 | ||
498 | /** | |
499 | * dccp_feat_push_confirm - Add a Confirm entry to the FN list | |
500 | * @fn_list: feature-negotiation list to add to | |
501 | * @feat: one of %dccp_feature_numbers | |
502 | * @local: whether local (1) or remote (0) @feat_num is being confirmed | |
503 | * @fval: pointer to NN/SP value to be inserted or NULL | |
504 | * | |
505 | * Returns 0 on success, a Reset code for further processing otherwise. | |
506 | */ | |
507 | static int dccp_feat_push_confirm(struct list_head *fn_list, u8 feat, u8 local, | |
508 | dccp_feat_val *fval) | |
509 | { | |
510 | struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local); | |
511 | ||
512 | if (new == NULL) | |
513 | return DCCP_RESET_CODE_TOO_BUSY; | |
514 | ||
515 | new->feat_num = feat; | |
516 | new->is_local = local; | |
517 | new->state = FEAT_STABLE; /* transition in 6.6.2 */ | |
518 | new->needs_confirm = true; | |
519 | new->empty_confirm = (fval == NULL); | |
520 | new->val.nn = 0; /* zeroes the whole structure */ | |
521 | if (!new->empty_confirm) | |
522 | new->val = *fval; | |
523 | new->needs_mandatory = false; | |
524 | ||
525 | return 0; | |
526 | } | |
527 | ||
528 | static int dccp_push_empty_confirm(struct list_head *fn_list, u8 feat, u8 local) | |
529 | { | |
530 | return dccp_feat_push_confirm(fn_list, feat, local, NULL); | |
531 | } | |
532 | ||
533 | static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry) | |
534 | { | |
535 | list_del(&entry->node); | |
536 | dccp_feat_entry_destructor(entry); | |
537 | } | |
538 | ||
539 | void dccp_feat_list_purge(struct list_head *fn_list) | |
540 | { | |
541 | struct dccp_feat_entry *entry, *next; | |
542 | ||
543 | list_for_each_entry_safe(entry, next, fn_list, node) | |
544 | dccp_feat_entry_destructor(entry); | |
545 | INIT_LIST_HEAD(fn_list); | |
546 | } | |
547 | EXPORT_SYMBOL_GPL(dccp_feat_list_purge); | |
548 | ||
549 | /* generate @to as full clone of @from - @to must not contain any nodes */ | |
550 | int dccp_feat_clone_list(struct list_head const *from, struct list_head *to) | |
551 | { | |
552 | struct dccp_feat_entry *entry, *new; | |
553 | ||
554 | INIT_LIST_HEAD(to); | |
555 | list_for_each_entry(entry, from, node) { | |
556 | new = dccp_feat_clone_entry(entry); | |
557 | if (new == NULL) | |
558 | goto cloning_failed; | |
559 | list_add_tail(&new->node, to); | |
560 | } | |
561 | return 0; | |
562 | ||
563 | cloning_failed: | |
564 | dccp_feat_list_purge(to); | |
565 | return -ENOMEM; | |
566 | } | |
567 | ||
568 | /** | |
569 | * dccp_feat_valid_nn_length - Enforce length constraints on NN options | |
570 | * Length is between 0 and %DCCP_OPTVAL_MAXLEN. Used for outgoing packets only, | |
571 | * incoming options are accepted as long as their values are valid. | |
572 | */ | |
573 | static u8 dccp_feat_valid_nn_length(u8 feat_num) | |
574 | { | |
575 | if (feat_num == DCCPF_ACK_RATIO) /* RFC 4340, 11.3 and 6.6.8 */ | |
576 | return 2; | |
577 | if (feat_num == DCCPF_SEQUENCE_WINDOW) /* RFC 4340, 7.5.2 and 6.5 */ | |
578 | return 6; | |
579 | return 0; | |
580 | } | |
581 | ||
582 | static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val) | |
583 | { | |
584 | switch (feat_num) { | |
585 | case DCCPF_ACK_RATIO: | |
586 | return val <= DCCPF_ACK_RATIO_MAX; | |
587 | case DCCPF_SEQUENCE_WINDOW: | |
588 | return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX; | |
589 | } | |
590 | return 0; /* feature unknown - so we can't tell */ | |
591 | } | |
592 | ||
593 | /* check that SP values are within the ranges defined in RFC 4340 */ | |
594 | static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val) | |
595 | { | |
596 | switch (feat_num) { | |
597 | case DCCPF_CCID: | |
598 | return val == DCCPC_CCID2 || val == DCCPC_CCID3; | |
599 | /* Type-check Boolean feature values: */ | |
600 | case DCCPF_SHORT_SEQNOS: | |
601 | case DCCPF_ECN_INCAPABLE: | |
602 | case DCCPF_SEND_ACK_VECTOR: | |
603 | case DCCPF_SEND_NDP_COUNT: | |
604 | case DCCPF_DATA_CHECKSUM: | |
605 | case DCCPF_SEND_LEV_RATE: | |
606 | return val < 2; | |
607 | case DCCPF_MIN_CSUM_COVER: | |
608 | return val < 16; | |
609 | } | |
610 | return 0; /* feature unknown */ | |
611 | } | |
612 | ||
613 | static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len) | |
614 | { | |
615 | if (sp_list == NULL || sp_len < 1) | |
616 | return 0; | |
617 | while (sp_len--) | |
618 | if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++)) | |
619 | return 0; | |
620 | return 1; | |
621 | } | |
622 | ||
623 | /** | |
624 | * dccp_feat_insert_opts - Generate FN options from current list state | |
625 | * @skb: next sk_buff to be sent to the peer | |
626 | * @dp: for client during handshake and general negotiation | |
627 | * @dreq: used by the server only (all Changes/Confirms in LISTEN/RESPOND) | |
628 | */ | |
629 | int dccp_feat_insert_opts(struct dccp_sock *dp, struct dccp_request_sock *dreq, | |
630 | struct sk_buff *skb) | |
631 | { | |
632 | struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg; | |
633 | struct dccp_feat_entry *pos, *next; | |
634 | u8 opt, type, len, *ptr, nn_in_nbo[DCCP_OPTVAL_MAXLEN]; | |
635 | bool rpt; | |
636 | ||
637 | /* put entries into @skb in the order they appear in the list */ | |
638 | list_for_each_entry_safe_reverse(pos, next, fn, node) { | |
639 | opt = dccp_feat_genopt(pos); | |
640 | type = dccp_feat_type(pos->feat_num); | |
641 | rpt = false; | |
642 | ||
643 | if (pos->empty_confirm) { | |
644 | len = 0; | |
645 | ptr = NULL; | |
646 | } else { | |
647 | if (type == FEAT_SP) { | |
648 | len = pos->val.sp.len; | |
649 | ptr = pos->val.sp.vec; | |
650 | rpt = pos->needs_confirm; | |
651 | } else if (type == FEAT_NN) { | |
652 | len = dccp_feat_valid_nn_length(pos->feat_num); | |
653 | ptr = nn_in_nbo; | |
654 | dccp_encode_value_var(pos->val.nn, ptr, len); | |
655 | } else { | |
656 | DCCP_BUG("unknown feature %u", pos->feat_num); | |
657 | return -1; | |
658 | } | |
659 | } | |
660 | dccp_feat_print_opt(opt, pos->feat_num, ptr, len, 0); | |
661 | ||
662 | if (dccp_insert_fn_opt(skb, opt, pos->feat_num, ptr, len, rpt)) | |
663 | return -1; | |
664 | if (pos->needs_mandatory && dccp_insert_option_mandatory(skb)) | |
665 | return -1; | |
666 | ||
667 | if (skb->sk->sk_state == DCCP_OPEN && | |
668 | (opt == DCCPO_CONFIRM_R || opt == DCCPO_CONFIRM_L)) { | |
669 | /* | |
670 | * Confirms don't get retransmitted (6.6.3) once the | |
671 | * connection is in state OPEN | |
672 | */ | |
673 | dccp_feat_list_pop(pos); | |
674 | } else { | |
675 | /* | |
676 | * Enter CHANGING after transmitting the Change | |
677 | * option (6.6.2). | |
678 | */ | |
679 | if (pos->state == FEAT_INITIALISING) | |
680 | pos->state = FEAT_CHANGING; | |
681 | } | |
682 | } | |
683 | return 0; | |
684 | } | |
685 | ||
686 | /** | |
687 | * __feat_register_nn - Register new NN value on socket | |
688 | * @fn: feature-negotiation list to register with | |
689 | * @feat: an NN feature from %dccp_feature_numbers | |
690 | * @mandatory: use Mandatory option if 1 | |
691 | * @nn_val: value to register (restricted to 4 bytes) | |
692 | * | |
693 | * Note that NN features are local by definition (RFC 4340, 6.3.2). | |
694 | */ | |
695 | static int __feat_register_nn(struct list_head *fn, u8 feat, | |
696 | u8 mandatory, u64 nn_val) | |
697 | { | |
698 | dccp_feat_val fval = { .nn = nn_val }; | |
699 | ||
700 | if (dccp_feat_type(feat) != FEAT_NN || | |
701 | !dccp_feat_is_valid_nn_val(feat, nn_val)) | |
702 | return -EINVAL; | |
703 | ||
704 | /* Don't bother with default values, they will be activated anyway. */ | |
705 | if (nn_val - (u64)dccp_feat_default_value(feat) == 0) | |
706 | return 0; | |
707 | ||
708 | return dccp_feat_push_change(fn, feat, 1, mandatory, &fval); | |
709 | } | |
710 | ||
711 | /** | |
712 | * __feat_register_sp - Register new SP value/list on socket | |
713 | * @fn: feature-negotiation list to register with | |
714 | * @feat: an SP feature from %dccp_feature_numbers | |
715 | * @is_local: whether the local (1) or the remote (0) @feat is meant | |
716 | * @mandatory: use Mandatory option if 1 | |
717 | * @sp_val: SP value followed by optional preference list | |
718 | * @sp_len: length of @sp_val in bytes | |
719 | */ | |
720 | static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local, | |
721 | u8 mandatory, u8 const *sp_val, u8 sp_len) | |
722 | { | |
723 | dccp_feat_val fval; | |
724 | ||
725 | if (dccp_feat_type(feat) != FEAT_SP || | |
726 | !dccp_feat_sp_list_ok(feat, sp_val, sp_len)) | |
727 | return -EINVAL; | |
728 | ||
729 | /* Avoid negotiating alien CCIDs by only advertising supported ones */ | |
730 | if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len)) | |
731 | return -EOPNOTSUPP; | |
732 | ||
733 | if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len)) | |
734 | return -ENOMEM; | |
735 | ||
736 | if (dccp_feat_push_change(fn, feat, is_local, mandatory, &fval)) { | |
737 | kfree(fval.sp.vec); | |
738 | return -ENOMEM; | |
739 | } | |
740 | ||
741 | return 0; | |
742 | } | |
743 | ||
744 | /** | |
745 | * dccp_feat_register_sp - Register requests to change SP feature values | |
746 | * @sk: client or listening socket | |
747 | * @feat: one of %dccp_feature_numbers | |
748 | * @is_local: whether the local (1) or remote (0) @feat is meant | |
749 | * @list: array of preferred values, in descending order of preference | |
750 | * @len: length of @list in bytes | |
751 | */ | |
752 | int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local, | |
753 | u8 const *list, u8 len) | |
754 | { /* any changes must be registered before establishing the connection */ | |
755 | if (sk->sk_state != DCCP_CLOSED) | |
756 | return -EISCONN; | |
757 | if (dccp_feat_type(feat) != FEAT_SP) | |
758 | return -EINVAL; | |
759 | return __feat_register_sp(&dccp_sk(sk)->dccps_featneg, feat, is_local, | |
760 | 0, list, len); | |
761 | } | |
762 | ||
763 | /** | |
764 | * dccp_feat_nn_get - Query current/pending value of NN feature | |
765 | * @sk: DCCP socket of an established connection | |
766 | * @feat: NN feature number from %dccp_feature_numbers | |
767 | * | |
768 | * For a known NN feature, returns value currently being negotiated, or | |
769 | * current (confirmed) value if no negotiation is going on. | |
770 | */ | |
771 | u64 dccp_feat_nn_get(struct sock *sk, u8 feat) | |
772 | { | |
773 | if (dccp_feat_type(feat) == FEAT_NN) { | |
774 | struct dccp_sock *dp = dccp_sk(sk); | |
775 | struct dccp_feat_entry *entry; | |
776 | ||
777 | entry = dccp_feat_list_lookup(&dp->dccps_featneg, feat, 1); | |
778 | if (entry != NULL) | |
779 | return entry->val.nn; | |
780 | ||
781 | switch (feat) { | |
782 | case DCCPF_ACK_RATIO: | |
783 | return dp->dccps_l_ack_ratio; | |
784 | case DCCPF_SEQUENCE_WINDOW: | |
785 | return dp->dccps_l_seq_win; | |
786 | } | |
787 | } | |
788 | DCCP_BUG("attempt to look up unsupported feature %u", feat); | |
789 | return 0; | |
790 | } | |
791 | EXPORT_SYMBOL_GPL(dccp_feat_nn_get); | |
792 | ||
793 | /** | |
794 | * dccp_feat_signal_nn_change - Update NN values for an established connection | |
795 | * @sk: DCCP socket of an established connection | |
796 | * @feat: NN feature number from %dccp_feature_numbers | |
797 | * @nn_val: the new value to use | |
798 | * | |
799 | * This function is used to communicate NN updates out-of-band. | |
800 | */ | |
801 | int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val) | |
802 | { | |
803 | struct list_head *fn = &dccp_sk(sk)->dccps_featneg; | |
804 | dccp_feat_val fval = { .nn = nn_val }; | |
805 | struct dccp_feat_entry *entry; | |
806 | ||
807 | if (sk->sk_state != DCCP_OPEN && sk->sk_state != DCCP_PARTOPEN) | |
808 | return 0; | |
809 | ||
810 | if (dccp_feat_type(feat) != FEAT_NN || | |
811 | !dccp_feat_is_valid_nn_val(feat, nn_val)) | |
812 | return -EINVAL; | |
813 | ||
814 | if (nn_val == dccp_feat_nn_get(sk, feat)) | |
815 | return 0; /* already set or negotiation under way */ | |
816 | ||
817 | entry = dccp_feat_list_lookup(fn, feat, 1); | |
818 | if (entry != NULL) { | |
819 | dccp_pr_debug("Clobbering existing NN entry %llu -> %llu\n", | |
820 | (unsigned long long)entry->val.nn, | |
821 | (unsigned long long)nn_val); | |
822 | dccp_feat_list_pop(entry); | |
823 | } | |
824 | ||
825 | inet_csk_schedule_ack(sk); | |
826 | return dccp_feat_push_change(fn, feat, 1, 0, &fval); | |
827 | } | |
828 | EXPORT_SYMBOL_GPL(dccp_feat_signal_nn_change); | |
829 | ||
830 | /* | |
831 | * Tracking features whose value depend on the choice of CCID | |
832 | * | |
833 | * This is designed with an extension in mind so that a list walk could be done | |
834 | * before activating any features. However, the existing framework was found to | |
835 | * work satisfactorily up until now, the automatic verification is left open. | |
836 | * When adding new CCIDs, add a corresponding dependency table here. | |
837 | */ | |
838 | static const struct ccid_dependency *dccp_feat_ccid_deps(u8 ccid, bool is_local) | |
839 | { | |
840 | static const struct ccid_dependency ccid2_dependencies[2][2] = { | |
841 | /* | |
842 | * CCID2 mandates Ack Vectors (RFC 4341, 4.): as CCID is a TX | |
843 | * feature and Send Ack Vector is an RX feature, `is_local' | |
844 | * needs to be reversed. | |
845 | */ | |
846 | { /* Dependencies of the receiver-side (remote) CCID2 */ | |
847 | { | |
848 | .dependent_feat = DCCPF_SEND_ACK_VECTOR, | |
849 | .is_local = true, | |
850 | .is_mandatory = true, | |
851 | .val = 1 | |
852 | }, | |
853 | { 0, 0, 0, 0 } | |
854 | }, | |
855 | { /* Dependencies of the sender-side (local) CCID2 */ | |
856 | { | |
857 | .dependent_feat = DCCPF_SEND_ACK_VECTOR, | |
858 | .is_local = false, | |
859 | .is_mandatory = true, | |
860 | .val = 1 | |
861 | }, | |
862 | { 0, 0, 0, 0 } | |
863 | } | |
864 | }; | |
865 | static const struct ccid_dependency ccid3_dependencies[2][5] = { | |
866 | { /* | |
867 | * Dependencies of the receiver-side CCID3 | |
868 | */ | |
869 | { /* locally disable Ack Vectors */ | |
870 | .dependent_feat = DCCPF_SEND_ACK_VECTOR, | |
871 | .is_local = true, | |
872 | .is_mandatory = false, | |
873 | .val = 0 | |
874 | }, | |
875 | { /* see below why Send Loss Event Rate is on */ | |
876 | .dependent_feat = DCCPF_SEND_LEV_RATE, | |
877 | .is_local = true, | |
878 | .is_mandatory = true, | |
879 | .val = 1 | |
880 | }, | |
881 | { /* NDP Count is needed as per RFC 4342, 6.1.1 */ | |
882 | .dependent_feat = DCCPF_SEND_NDP_COUNT, | |
883 | .is_local = false, | |
884 | .is_mandatory = true, | |
885 | .val = 1 | |
886 | }, | |
887 | { 0, 0, 0, 0 }, | |
888 | }, | |
889 | { /* | |
890 | * CCID3 at the TX side: we request that the HC-receiver | |
891 | * will not send Ack Vectors (they will be ignored, so | |
892 | * Mandatory is not set); we enable Send Loss Event Rate | |
893 | * (Mandatory since the implementation does not support | |
894 | * the Loss Intervals option of RFC 4342, 8.6). | |
895 | * The last two options are for peer's information only. | |
896 | */ | |
897 | { | |
898 | .dependent_feat = DCCPF_SEND_ACK_VECTOR, | |
899 | .is_local = false, | |
900 | .is_mandatory = false, | |
901 | .val = 0 | |
902 | }, | |
903 | { | |
904 | .dependent_feat = DCCPF_SEND_LEV_RATE, | |
905 | .is_local = false, | |
906 | .is_mandatory = true, | |
907 | .val = 1 | |
908 | }, | |
909 | { /* this CCID does not support Ack Ratio */ | |
910 | .dependent_feat = DCCPF_ACK_RATIO, | |
911 | .is_local = true, | |
912 | .is_mandatory = false, | |
913 | .val = 0 | |
914 | }, | |
915 | { /* tell receiver we are sending NDP counts */ | |
916 | .dependent_feat = DCCPF_SEND_NDP_COUNT, | |
917 | .is_local = true, | |
918 | .is_mandatory = false, | |
919 | .val = 1 | |
920 | }, | |
921 | { 0, 0, 0, 0 } | |
922 | } | |
923 | }; | |
924 | switch (ccid) { | |
925 | case DCCPC_CCID2: | |
926 | return ccid2_dependencies[is_local]; | |
927 | case DCCPC_CCID3: | |
928 | return ccid3_dependencies[is_local]; | |
929 | default: | |
930 | return NULL; | |
931 | } | |
932 | } | |
933 | ||
934 | /** | |
935 | * dccp_feat_propagate_ccid - Resolve dependencies of features on choice of CCID | |
936 | * @fn: feature-negotiation list to update | |
937 | * @id: CCID number to track | |
938 | * @is_local: whether TX CCID (1) or RX CCID (0) is meant | |
939 | * | |
940 | * This function needs to be called after registering all other features. | |
941 | */ | |
942 | static int dccp_feat_propagate_ccid(struct list_head *fn, u8 id, bool is_local) | |
943 | { | |
944 | const struct ccid_dependency *table = dccp_feat_ccid_deps(id, is_local); | |
945 | int i, rc = (table == NULL); | |
946 | ||
947 | for (i = 0; rc == 0 && table[i].dependent_feat != DCCPF_RESERVED; i++) | |
948 | if (dccp_feat_type(table[i].dependent_feat) == FEAT_SP) | |
949 | rc = __feat_register_sp(fn, table[i].dependent_feat, | |
950 | table[i].is_local, | |
951 | table[i].is_mandatory, | |
952 | &table[i].val, 1); | |
953 | else | |
954 | rc = __feat_register_nn(fn, table[i].dependent_feat, | |
955 | table[i].is_mandatory, | |
956 | table[i].val); | |
957 | return rc; | |
958 | } | |
959 | ||
960 | /** | |
961 | * dccp_feat_finalise_settings - Finalise settings before starting negotiation | |
962 | * @dp: client or listening socket (settings will be inherited) | |
963 | * | |
964 | * This is called after all registrations (socket initialisation, sysctls, and | |
965 | * sockopt calls), and before sending the first packet containing Change options | |
966 | * (ie. client-Request or server-Response), to ensure internal consistency. | |
967 | */ | |
968 | int dccp_feat_finalise_settings(struct dccp_sock *dp) | |
969 | { | |
970 | struct list_head *fn = &dp->dccps_featneg; | |
971 | struct dccp_feat_entry *entry; | |
972 | int i = 2, ccids[2] = { -1, -1 }; | |
973 | ||
974 | /* | |
975 | * Propagating CCIDs: | |
976 | * 1) not useful to propagate CCID settings if this host advertises more | |
977 | * than one CCID: the choice of CCID may still change - if this is | |
978 | * the client, or if this is the server and the client sends | |
979 | * singleton CCID values. | |
980 | * 2) since is that propagate_ccid changes the list, we defer changing | |
981 | * the sorted list until after the traversal. | |
982 | */ | |
983 | list_for_each_entry(entry, fn, node) | |
984 | if (entry->feat_num == DCCPF_CCID && entry->val.sp.len == 1) | |
985 | ccids[entry->is_local] = entry->val.sp.vec[0]; | |
986 | while (i--) | |
987 | if (ccids[i] > 0 && dccp_feat_propagate_ccid(fn, ccids[i], i)) | |
988 | return -1; | |
989 | dccp_feat_print_fnlist(fn); | |
990 | return 0; | |
991 | } | |
992 | ||
993 | /** | |
994 | * dccp_feat_server_ccid_dependencies - Resolve CCID-dependent features | |
995 | * It is the server which resolves the dependencies once the CCID has been | |
996 | * fully negotiated. If no CCID has been negotiated, it uses the default CCID. | |
997 | */ | |
998 | int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq) | |
999 | { | |
1000 | struct list_head *fn = &dreq->dreq_featneg; | |
1001 | struct dccp_feat_entry *entry; | |
1002 | u8 is_local, ccid; | |
1003 | ||
1004 | for (is_local = 0; is_local <= 1; is_local++) { | |
1005 | entry = dccp_feat_list_lookup(fn, DCCPF_CCID, is_local); | |
1006 | ||
1007 | if (entry != NULL && !entry->empty_confirm) | |
1008 | ccid = entry->val.sp.vec[0]; | |
1009 | else | |
1010 | ccid = dccp_feat_default_value(DCCPF_CCID); | |
1011 | ||
1012 | if (dccp_feat_propagate_ccid(fn, ccid, is_local)) | |
1013 | return -1; | |
1014 | } | |
1015 | return 0; | |
1016 | } | |
1017 | ||
1018 | /* Select the first entry in @servlist that also occurs in @clilist (6.3.1) */ | |
1019 | static int dccp_feat_preflist_match(u8 *servlist, u8 slen, u8 *clilist, u8 clen) | |
1020 | { | |
1021 | u8 c, s; | |
1022 | ||
1023 | for (s = 0; s < slen; s++) | |
1024 | for (c = 0; c < clen; c++) | |
1025 | if (servlist[s] == clilist[c]) | |
1026 | return servlist[s]; | |
1027 | return -1; | |
1028 | } | |
1029 | ||
1030 | /** | |
1031 | * dccp_feat_prefer - Move preferred entry to the start of array | |
1032 | * Reorder the @array_len elements in @array so that @preferred_value comes | |
1033 | * first. Returns >0 to indicate that @preferred_value does occur in @array. | |
1034 | */ | |
1035 | static u8 dccp_feat_prefer(u8 preferred_value, u8 *array, u8 array_len) | |
1036 | { | |
1037 | u8 i, does_occur = 0; | |
1038 | ||
1039 | if (array != NULL) { | |
1040 | for (i = 0; i < array_len; i++) | |
1041 | if (array[i] == preferred_value) { | |
1042 | array[i] = array[0]; | |
1043 | does_occur++; | |
1044 | } | |
1045 | if (does_occur) | |
1046 | array[0] = preferred_value; | |
1047 | } | |
1048 | return does_occur; | |
1049 | } | |
1050 | ||
1051 | /** | |
1052 | * dccp_feat_reconcile - Reconcile SP preference lists | |
1053 | * @fv: SP list to reconcile into | |
1054 | * @arr: received SP preference list | |
1055 | * @len: length of @arr in bytes | |
1056 | * @is_server: whether this side is the server (and @fv is the server's list) | |
1057 | * @reorder: whether to reorder the list in @fv after reconciling with @arr | |
1058 | * When successful, > 0 is returned and the reconciled list is in @fval. | |
1059 | * A value of 0 means that negotiation failed (no shared entry). | |
1060 | */ | |
1061 | static int dccp_feat_reconcile(dccp_feat_val *fv, u8 *arr, u8 len, | |
1062 | bool is_server, bool reorder) | |
1063 | { | |
1064 | int rc; | |
1065 | ||
1066 | if (!fv->sp.vec || !arr) { | |
1067 | DCCP_CRIT("NULL feature value or array"); | |
1068 | return 0; | |
1069 | } | |
1070 | ||
1071 | if (is_server) | |
1072 | rc = dccp_feat_preflist_match(fv->sp.vec, fv->sp.len, arr, len); | |
1073 | else | |
1074 | rc = dccp_feat_preflist_match(arr, len, fv->sp.vec, fv->sp.len); | |
1075 | ||
1076 | if (!reorder) | |
1077 | return rc; | |
1078 | if (rc < 0) | |
1079 | return 0; | |
1080 | ||
1081 | /* | |
1082 | * Reorder list: used for activating features and in dccp_insert_fn_opt. | |
1083 | */ | |
1084 | return dccp_feat_prefer(rc, fv->sp.vec, fv->sp.len); | |
1085 | } | |
1086 | ||
1087 | /** | |
1088 | * dccp_feat_change_recv - Process incoming ChangeL/R options | |
1089 | * @fn: feature-negotiation list to update | |
1090 | * @is_mandatory: whether the Change was preceded by a Mandatory option | |
1091 | * @opt: %DCCPO_CHANGE_L or %DCCPO_CHANGE_R | |
1092 | * @feat: one of %dccp_feature_numbers | |
1093 | * @val: NN value or SP value/preference list | |
1094 | * @len: length of @val in bytes | |
1095 | * @server: whether this node is the server (1) or the client (0) | |
1096 | */ | |
1097 | static u8 dccp_feat_change_recv(struct list_head *fn, u8 is_mandatory, u8 opt, | |
1098 | u8 feat, u8 *val, u8 len, const bool server) | |
1099 | { | |
1100 | u8 defval, type = dccp_feat_type(feat); | |
1101 | const bool local = (opt == DCCPO_CHANGE_R); | |
1102 | struct dccp_feat_entry *entry; | |
1103 | dccp_feat_val fval; | |
1104 | ||
1105 | if (len == 0 || type == FEAT_UNKNOWN) /* 6.1 and 6.6.8 */ | |
1106 | goto unknown_feature_or_value; | |
1107 | ||
1108 | dccp_feat_print_opt(opt, feat, val, len, is_mandatory); | |
1109 | ||
1110 | /* | |
1111 | * Negotiation of NN features: Change R is invalid, so there is no | |
1112 | * simultaneous negotiation; hence we do not look up in the list. | |
1113 | */ | |
1114 | if (type == FEAT_NN) { | |
1115 | if (local || len > sizeof(fval.nn)) | |
1116 | goto unknown_feature_or_value; | |
1117 | ||
1118 | /* 6.3.2: "The feature remote MUST accept any valid value..." */ | |
1119 | fval.nn = dccp_decode_value_var(val, len); | |
1120 | if (!dccp_feat_is_valid_nn_val(feat, fval.nn)) | |
1121 | goto unknown_feature_or_value; | |
1122 | ||
1123 | return dccp_feat_push_confirm(fn, feat, local, &fval); | |
1124 | } | |
1125 | ||
1126 | /* | |
1127 | * Unidirectional/simultaneous negotiation of SP features (6.3.1) | |
1128 | */ | |
1129 | entry = dccp_feat_list_lookup(fn, feat, local); | |
1130 | if (entry == NULL) { | |
1131 | /* | |
1132 | * No particular preferences have been registered. We deal with | |
1133 | * this situation by assuming that all valid values are equally | |
1134 | * acceptable, and apply the following checks: | |
1135 | * - if the peer's list is a singleton, we accept a valid value; | |
1136 | * - if we are the server, we first try to see if the peer (the | |
1137 | * client) advertises the default value. If yes, we use it, | |
1138 | * otherwise we accept the preferred value; | |
1139 | * - else if we are the client, we use the first list element. | |
1140 | */ | |
1141 | if (dccp_feat_clone_sp_val(&fval, val, 1)) | |
1142 | return DCCP_RESET_CODE_TOO_BUSY; | |
1143 | ||
1144 | if (len > 1 && server) { | |
1145 | defval = dccp_feat_default_value(feat); | |
1146 | if (dccp_feat_preflist_match(&defval, 1, val, len) > -1) | |
1147 | fval.sp.vec[0] = defval; | |
1148 | } else if (!dccp_feat_is_valid_sp_val(feat, fval.sp.vec[0])) { | |
1149 | kfree(fval.sp.vec); | |
1150 | goto unknown_feature_or_value; | |
1151 | } | |
1152 | ||
1153 | /* Treat unsupported CCIDs like invalid values */ | |
1154 | if (feat == DCCPF_CCID && !ccid_support_check(fval.sp.vec, 1)) { | |
1155 | kfree(fval.sp.vec); | |
1156 | goto not_valid_or_not_known; | |
1157 | } | |
1158 | ||
1159 | return dccp_feat_push_confirm(fn, feat, local, &fval); | |
1160 | ||
1161 | } else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */ | |
1162 | return 0; | |
1163 | } | |
1164 | ||
1165 | if (dccp_feat_reconcile(&entry->val, val, len, server, true)) { | |
1166 | entry->empty_confirm = false; | |
1167 | } else if (is_mandatory) { | |
1168 | return DCCP_RESET_CODE_MANDATORY_ERROR; | |
1169 | } else if (entry->state == FEAT_INITIALISING) { | |
1170 | /* | |
1171 | * Failed simultaneous negotiation (server only): try to `save' | |
1172 | * the connection by checking whether entry contains the default | |
1173 | * value for @feat. If yes, send an empty Confirm to signal that | |
1174 | * the received Change was not understood - which implies using | |
1175 | * the default value. | |
1176 | * If this also fails, we use Reset as the last resort. | |
1177 | */ | |
1178 | WARN_ON(!server); | |
1179 | defval = dccp_feat_default_value(feat); | |
1180 | if (!dccp_feat_reconcile(&entry->val, &defval, 1, server, true)) | |
1181 | return DCCP_RESET_CODE_OPTION_ERROR; | |
1182 | entry->empty_confirm = true; | |
1183 | } | |
1184 | entry->needs_confirm = true; | |
1185 | entry->needs_mandatory = false; | |
1186 | entry->state = FEAT_STABLE; | |
1187 | return 0; | |
1188 | ||
1189 | unknown_feature_or_value: | |
1190 | if (!is_mandatory) | |
1191 | return dccp_push_empty_confirm(fn, feat, local); | |
1192 | ||
1193 | not_valid_or_not_known: | |
1194 | return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR | |
1195 | : DCCP_RESET_CODE_OPTION_ERROR; | |
1196 | } | |
1197 | ||
1198 | /** | |
1199 | * dccp_feat_confirm_recv - Process received Confirm options | |
1200 | * @fn: feature-negotiation list to update | |
1201 | * @is_mandatory: whether @opt was preceded by a Mandatory option | |
1202 | * @opt: %DCCPO_CONFIRM_L or %DCCPO_CONFIRM_R | |
1203 | * @feat: one of %dccp_feature_numbers | |
1204 | * @val: NN value or SP value/preference list | |
1205 | * @len: length of @val in bytes | |
1206 | * @server: whether this node is server (1) or client (0) | |
1207 | */ | |
1208 | static u8 dccp_feat_confirm_recv(struct list_head *fn, u8 is_mandatory, u8 opt, | |
1209 | u8 feat, u8 *val, u8 len, const bool server) | |
1210 | { | |
1211 | u8 *plist, plen, type = dccp_feat_type(feat); | |
1212 | const bool local = (opt == DCCPO_CONFIRM_R); | |
1213 | struct dccp_feat_entry *entry = dccp_feat_list_lookup(fn, feat, local); | |
1214 | ||
1215 | dccp_feat_print_opt(opt, feat, val, len, is_mandatory); | |
1216 | ||
1217 | if (entry == NULL) { /* nothing queued: ignore or handle error */ | |
1218 | if (is_mandatory && type == FEAT_UNKNOWN) | |
1219 | return DCCP_RESET_CODE_MANDATORY_ERROR; | |
1220 | ||
1221 | if (!local && type == FEAT_NN) /* 6.3.2 */ | |
1222 | goto confirmation_failed; | |
1223 | return 0; | |
1224 | } | |
1225 | ||
1226 | if (entry->state != FEAT_CHANGING) /* 6.6.2 */ | |
1227 | return 0; | |
1228 | ||
1229 | if (len == 0) { | |
1230 | if (dccp_feat_must_be_understood(feat)) /* 6.6.7 */ | |
1231 | goto confirmation_failed; | |
1232 | /* | |
1233 | * Empty Confirm during connection setup: this means reverting | |
1234 | * to the `old' value, which in this case is the default. Since | |
1235 | * we handle default values automatically when no other values | |
1236 | * have been set, we revert to the old value by removing this | |
1237 | * entry from the list. | |
1238 | */ | |
1239 | dccp_feat_list_pop(entry); | |
1240 | return 0; | |
1241 | } | |
1242 | ||
1243 | if (type == FEAT_NN) { | |
1244 | if (len > sizeof(entry->val.nn)) | |
1245 | goto confirmation_failed; | |
1246 | ||
1247 | if (entry->val.nn == dccp_decode_value_var(val, len)) | |
1248 | goto confirmation_succeeded; | |
1249 | ||
1250 | DCCP_WARN("Bogus Confirm for non-existing value\n"); | |
1251 | goto confirmation_failed; | |
1252 | } | |
1253 | ||
1254 | /* | |
1255 | * Parsing SP Confirms: the first element of @val is the preferred | |
1256 | * SP value which the peer confirms, the remainder depends on @len. | |
1257 | * Note that only the confirmed value need to be a valid SP value. | |
1258 | */ | |
1259 | if (!dccp_feat_is_valid_sp_val(feat, *val)) | |
1260 | goto confirmation_failed; | |
1261 | ||
1262 | if (len == 1) { /* peer didn't supply a preference list */ | |
1263 | plist = val; | |
1264 | plen = len; | |
1265 | } else { /* preferred value + preference list */ | |
1266 | plist = val + 1; | |
1267 | plen = len - 1; | |
1268 | } | |
1269 | ||
1270 | /* Check whether the peer got the reconciliation right (6.6.8) */ | |
1271 | if (dccp_feat_reconcile(&entry->val, plist, plen, server, 0) != *val) { | |
1272 | DCCP_WARN("Confirm selected the wrong value %u\n", *val); | |
1273 | return DCCP_RESET_CODE_OPTION_ERROR; | |
1274 | } | |
1275 | entry->val.sp.vec[0] = *val; | |
1276 | ||
1277 | confirmation_succeeded: | |
1278 | entry->state = FEAT_STABLE; | |
1279 | return 0; | |
1280 | ||
1281 | confirmation_failed: | |
1282 | DCCP_WARN("Confirmation failed\n"); | |
1283 | return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR | |
1284 | : DCCP_RESET_CODE_OPTION_ERROR; | |
1285 | } | |
1286 | ||
1287 | /** | |
1288 | * dccp_feat_handle_nn_established - Fast-path reception of NN options | |
1289 | * @sk: socket of an established DCCP connection | |
1290 | * @mandatory: whether @opt was preceded by a Mandatory option | |
1291 | * @opt: %DCCPO_CHANGE_L | %DCCPO_CONFIRM_R (NN only) | |
1292 | * @feat: NN number, one of %dccp_feature_numbers | |
1293 | * @val: NN value | |
1294 | * @len: length of @val in bytes | |
1295 | * | |
1296 | * This function combines the functionality of change_recv/confirm_recv, with | |
1297 | * the following differences (reset codes are the same): | |
1298 | * - cleanup after receiving the Confirm; | |
1299 | * - values are directly activated after successful parsing; | |
1300 | * - deliberately restricted to NN features. | |
1301 | * The restriction to NN features is essential since SP features can have non- | |
1302 | * predictable outcomes (depending on the remote configuration), and are inter- | |
1303 | * dependent (CCIDs for instance cause further dependencies). | |
1304 | */ | |
1305 | static u8 dccp_feat_handle_nn_established(struct sock *sk, u8 mandatory, u8 opt, | |
1306 | u8 feat, u8 *val, u8 len) | |
1307 | { | |
1308 | struct list_head *fn = &dccp_sk(sk)->dccps_featneg; | |
1309 | const bool local = (opt == DCCPO_CONFIRM_R); | |
1310 | struct dccp_feat_entry *entry; | |
1311 | u8 type = dccp_feat_type(feat); | |
1312 | dccp_feat_val fval; | |
1313 | ||
1314 | dccp_feat_print_opt(opt, feat, val, len, mandatory); | |
1315 | ||
1316 | /* Ignore non-mandatory unknown and non-NN features */ | |
1317 | if (type == FEAT_UNKNOWN) { | |
1318 | if (local && !mandatory) | |
1319 | return 0; | |
1320 | goto fast_path_unknown; | |
1321 | } else if (type != FEAT_NN) { | |
1322 | return 0; | |
1323 | } | |
1324 | ||
1325 | /* | |
1326 | * We don't accept empty Confirms, since in fast-path feature | |
1327 | * negotiation the values are enabled immediately after sending | |
1328 | * the Change option. | |
1329 | * Empty Changes on the other hand are invalid (RFC 4340, 6.1). | |
1330 | */ | |
1331 | if (len == 0 || len > sizeof(fval.nn)) | |
1332 | goto fast_path_unknown; | |
1333 | ||
1334 | if (opt == DCCPO_CHANGE_L) { | |
1335 | fval.nn = dccp_decode_value_var(val, len); | |
1336 | if (!dccp_feat_is_valid_nn_val(feat, fval.nn)) | |
1337 | goto fast_path_unknown; | |
1338 | ||
1339 | if (dccp_feat_push_confirm(fn, feat, local, &fval) || | |
1340 | dccp_feat_activate(sk, feat, local, &fval)) | |
1341 | return DCCP_RESET_CODE_TOO_BUSY; | |
1342 | ||
1343 | /* set the `Ack Pending' flag to piggyback a Confirm */ | |
1344 | inet_csk_schedule_ack(sk); | |
1345 | ||
1346 | } else if (opt == DCCPO_CONFIRM_R) { | |
1347 | entry = dccp_feat_list_lookup(fn, feat, local); | |
1348 | if (entry == NULL || entry->state != FEAT_CHANGING) | |
1349 | return 0; | |
1350 | ||
1351 | fval.nn = dccp_decode_value_var(val, len); | |
1352 | /* | |
1353 | * Just ignore a value that doesn't match our current value. | |
1354 | * If the option changes twice within two RTTs, then at least | |
1355 | * one CONFIRM will be received for the old value after a | |
1356 | * new CHANGE was sent. | |
1357 | */ | |
1358 | if (fval.nn != entry->val.nn) | |
1359 | return 0; | |
1360 | ||
1361 | /* Only activate after receiving the Confirm option (6.6.1). */ | |
1362 | dccp_feat_activate(sk, feat, local, &fval); | |
1363 | ||
1364 | /* It has been confirmed - so remove the entry */ | |
1365 | dccp_feat_list_pop(entry); | |
1366 | ||
1367 | } else { | |
1368 | DCCP_WARN("Received illegal option %u\n", opt); | |
1369 | goto fast_path_failed; | |
1370 | } | |
1371 | return 0; | |
1372 | ||
1373 | fast_path_unknown: | |
1374 | if (!mandatory) | |
1375 | return dccp_push_empty_confirm(fn, feat, local); | |
1376 | ||
1377 | fast_path_failed: | |
1378 | return mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR | |
1379 | : DCCP_RESET_CODE_OPTION_ERROR; | |
1380 | } | |
1381 | ||
1382 | /** | |
1383 | * dccp_feat_parse_options - Process Feature-Negotiation Options | |
1384 | * @sk: for general use and used by the client during connection setup | |
1385 | * @dreq: used by the server during connection setup | |
1386 | * @mandatory: whether @opt was preceded by a Mandatory option | |
1387 | * @opt: %DCCPO_CHANGE_L | %DCCPO_CHANGE_R | %DCCPO_CONFIRM_L | %DCCPO_CONFIRM_R | |
1388 | * @feat: one of %dccp_feature_numbers | |
1389 | * @val: value contents of @opt | |
1390 | * @len: length of @val in bytes | |
1391 | * | |
1392 | * Returns 0 on success, a Reset code for ending the connection otherwise. | |
1393 | */ | |
1394 | int dccp_feat_parse_options(struct sock *sk, struct dccp_request_sock *dreq, | |
1395 | u8 mandatory, u8 opt, u8 feat, u8 *val, u8 len) | |
1396 | { | |
1397 | struct dccp_sock *dp = dccp_sk(sk); | |
1398 | struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg; | |
1399 | bool server = false; | |
1400 | ||
1401 | switch (sk->sk_state) { | |
1402 | /* | |
1403 | * Negotiation during connection setup | |
1404 | */ | |
1405 | case DCCP_LISTEN: | |
1406 | server = true; /* fall through */ | |
1407 | case DCCP_REQUESTING: | |
1408 | switch (opt) { | |
1409 | case DCCPO_CHANGE_L: | |
1410 | case DCCPO_CHANGE_R: | |
1411 | return dccp_feat_change_recv(fn, mandatory, opt, feat, | |
1412 | val, len, server); | |
1413 | case DCCPO_CONFIRM_R: | |
1414 | case DCCPO_CONFIRM_L: | |
1415 | return dccp_feat_confirm_recv(fn, mandatory, opt, feat, | |
1416 | val, len, server); | |
1417 | } | |
1418 | break; | |
1419 | /* | |
1420 | * Support for exchanging NN options on an established connection. | |
1421 | */ | |
1422 | case DCCP_OPEN: | |
1423 | case DCCP_PARTOPEN: | |
1424 | return dccp_feat_handle_nn_established(sk, mandatory, opt, feat, | |
1425 | val, len); | |
1426 | } | |
1427 | return 0; /* ignore FN options in all other states */ | |
1428 | } | |
1429 | ||
1430 | /** | |
1431 | * dccp_feat_init - Seed feature negotiation with host-specific defaults | |
1432 | * This initialises global defaults, depending on the value of the sysctls. | |
1433 | * These can later be overridden by registering changes via setsockopt calls. | |
1434 | * The last link in the chain is finalise_settings, to make sure that between | |
1435 | * here and the start of actual feature negotiation no inconsistencies enter. | |
1436 | * | |
1437 | * All features not appearing below use either defaults or are otherwise | |
1438 | * later adjusted through dccp_feat_finalise_settings(). | |
1439 | */ | |
1440 | int dccp_feat_init(struct sock *sk) | |
1441 | { | |
1442 | struct list_head *fn = &dccp_sk(sk)->dccps_featneg; | |
1443 | u8 on = 1, off = 0; | |
1444 | int rc; | |
1445 | struct { | |
1446 | u8 *val; | |
1447 | u8 len; | |
1448 | } tx, rx; | |
1449 | ||
1450 | /* Non-negotiable (NN) features */ | |
1451 | rc = __feat_register_nn(fn, DCCPF_SEQUENCE_WINDOW, 0, | |
1452 | sysctl_dccp_sequence_window); | |
1453 | if (rc) | |
1454 | return rc; | |
1455 | ||
1456 | /* Server-priority (SP) features */ | |
1457 | ||
1458 | /* Advertise that short seqnos are not supported (7.6.1) */ | |
1459 | rc = __feat_register_sp(fn, DCCPF_SHORT_SEQNOS, true, true, &off, 1); | |
1460 | if (rc) | |
1461 | return rc; | |
1462 | ||
1463 | /* RFC 4340 12.1: "If a DCCP is not ECN capable, ..." */ | |
1464 | rc = __feat_register_sp(fn, DCCPF_ECN_INCAPABLE, true, true, &on, 1); | |
1465 | if (rc) | |
1466 | return rc; | |
1467 | ||
1468 | /* | |
1469 | * We advertise the available list of CCIDs and reorder according to | |
1470 | * preferences, to avoid failure resulting from negotiating different | |
1471 | * singleton values (which always leads to failure). | |
1472 | * These settings can still (later) be overridden via sockopts. | |
1473 | */ | |
1474 | if (ccid_get_builtin_ccids(&tx.val, &tx.len)) | |
1475 | return -ENOBUFS; | |
1476 | if (ccid_get_builtin_ccids(&rx.val, &rx.len)) { | |
1477 | kfree(tx.val); | |
1478 | return -ENOBUFS; | |
1479 | } | |
1480 | ||
1481 | if (!dccp_feat_prefer(sysctl_dccp_tx_ccid, tx.val, tx.len) || | |
1482 | !dccp_feat_prefer(sysctl_dccp_rx_ccid, rx.val, rx.len)) | |
1483 | goto free_ccid_lists; | |
1484 | ||
1485 | rc = __feat_register_sp(fn, DCCPF_CCID, true, false, tx.val, tx.len); | |
1486 | if (rc) | |
1487 | goto free_ccid_lists; | |
1488 | ||
1489 | rc = __feat_register_sp(fn, DCCPF_CCID, false, false, rx.val, rx.len); | |
1490 | ||
1491 | free_ccid_lists: | |
1492 | kfree(tx.val); | |
1493 | kfree(rx.val); | |
1494 | return rc; | |
1495 | } | |
1496 | ||
1497 | int dccp_feat_activate_values(struct sock *sk, struct list_head *fn_list) | |
1498 | { | |
1499 | struct dccp_sock *dp = dccp_sk(sk); | |
1500 | struct dccp_feat_entry *cur, *next; | |
1501 | int idx; | |
1502 | dccp_feat_val *fvals[DCCP_FEAT_SUPPORTED_MAX][2] = { | |
1503 | [0 ... DCCP_FEAT_SUPPORTED_MAX-1] = { NULL, NULL } | |
1504 | }; | |
1505 | ||
1506 | list_for_each_entry(cur, fn_list, node) { | |
1507 | /* | |
1508 | * An empty Confirm means that either an unknown feature type | |
1509 | * or an invalid value was present. In the first case there is | |
1510 | * nothing to activate, in the other the default value is used. | |
1511 | */ | |
1512 | if (cur->empty_confirm) | |
1513 | continue; | |
1514 | ||
1515 | idx = dccp_feat_index(cur->feat_num); | |
1516 | if (idx < 0) { | |
1517 | DCCP_BUG("Unknown feature %u", cur->feat_num); | |
1518 | goto activation_failed; | |
1519 | } | |
1520 | if (cur->state != FEAT_STABLE) { | |
1521 | DCCP_CRIT("Negotiation of %s %s failed in state %s", | |
1522 | cur->is_local ? "local" : "remote", | |
1523 | dccp_feat_fname(cur->feat_num), | |
1524 | dccp_feat_sname[cur->state]); | |
1525 | goto activation_failed; | |
1526 | } | |
1527 | fvals[idx][cur->is_local] = &cur->val; | |
1528 | } | |
1529 | ||
1530 | /* | |
1531 | * Activate in decreasing order of index, so that the CCIDs are always | |
1532 | * activated as the last feature. This avoids the case where a CCID | |
1533 | * relies on the initialisation of one or more features that it depends | |
1534 | * on (e.g. Send NDP Count, Send Ack Vector, and Ack Ratio features). | |
1535 | */ | |
1536 | for (idx = DCCP_FEAT_SUPPORTED_MAX; --idx >= 0;) | |
1537 | if (__dccp_feat_activate(sk, idx, 0, fvals[idx][0]) || | |
1538 | __dccp_feat_activate(sk, idx, 1, fvals[idx][1])) { | |
1539 | DCCP_CRIT("Could not activate %d", idx); | |
1540 | goto activation_failed; | |
1541 | } | |
1542 | ||
1543 | /* Clean up Change options which have been confirmed already */ | |
1544 | list_for_each_entry_safe(cur, next, fn_list, node) | |
1545 | if (!cur->needs_confirm) | |
1546 | dccp_feat_list_pop(cur); | |
1547 | ||
1548 | dccp_pr_debug("Activation OK\n"); | |
1549 | return 0; | |
1550 | ||
1551 | activation_failed: | |
1552 | /* | |
1553 | * We clean up everything that may have been allocated, since | |
1554 | * it is difficult to track at which stage negotiation failed. | |
1555 | * This is ok, since all allocation functions below are robust | |
1556 | * against NULL arguments. | |
1557 | */ | |
1558 | ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); | |
1559 | ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); | |
1560 | dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL; | |
1561 | dccp_ackvec_free(dp->dccps_hc_rx_ackvec); | |
1562 | dp->dccps_hc_rx_ackvec = NULL; | |
1563 | return -1; | |
1564 | } |