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322345fd LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
b5efdb8a | 22 | #include "alloc-util.h" |
58db254a | 23 | #include "dns-domain.h" |
02c2857b | 24 | #include "resolved-dns-answer.h" |
322345fd | 25 | #include "resolved-dns-cache.h" |
7e8e0422 | 26 | #include "resolved-dns-packet.h" |
58db254a | 27 | #include "string-util.h" |
322345fd | 28 | |
cbd4560e | 29 | /* Never cache more than 1K entries */ |
322345fd | 30 | #define CACHE_MAX 1024 |
cbd4560e LP |
31 | |
32 | /* We never keep any item longer than 10min in our cache */ | |
322345fd LP |
33 | #define CACHE_TTL_MAX_USEC (10 * USEC_PER_MINUTE) |
34 | ||
623a4c97 LP |
35 | typedef enum DnsCacheItemType DnsCacheItemType; |
36 | typedef struct DnsCacheItem DnsCacheItem; | |
37 | ||
38 | enum DnsCacheItemType { | |
39 | DNS_CACHE_POSITIVE, | |
40 | DNS_CACHE_NODATA, | |
41 | DNS_CACHE_NXDOMAIN, | |
42 | }; | |
43 | ||
44 | struct DnsCacheItem { | |
45 | DnsResourceKey *key; | |
46 | DnsResourceRecord *rr; | |
47 | usec_t until; | |
48 | DnsCacheItemType type; | |
49 | unsigned prioq_idx; | |
931851e8 | 50 | bool authenticated; |
a4076574 LP |
51 | int owner_family; |
52 | union in_addr_union owner_address; | |
623a4c97 LP |
53 | LIST_FIELDS(DnsCacheItem, by_key); |
54 | }; | |
55 | ||
322345fd LP |
56 | static void dns_cache_item_free(DnsCacheItem *i) { |
57 | if (!i) | |
58 | return; | |
59 | ||
60 | dns_resource_record_unref(i->rr); | |
7e8e0422 | 61 | dns_resource_key_unref(i->key); |
322345fd LP |
62 | free(i); |
63 | } | |
64 | ||
65 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsCacheItem*, dns_cache_item_free); | |
66 | ||
67 | static void dns_cache_item_remove_and_free(DnsCache *c, DnsCacheItem *i) { | |
68 | DnsCacheItem *first; | |
69 | ||
70 | assert(c); | |
71 | ||
72 | if (!i) | |
73 | return; | |
74 | ||
7e8e0422 LP |
75 | first = hashmap_get(c->by_key, i->key); |
76 | LIST_REMOVE(by_key, first, i); | |
322345fd LP |
77 | |
78 | if (first) | |
7e8e0422 | 79 | assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); |
322345fd | 80 | else |
7e8e0422 | 81 | hashmap_remove(c->by_key, i->key); |
322345fd | 82 | |
7e8e0422 | 83 | prioq_remove(c->by_expiry, i, &i->prioq_idx); |
322345fd LP |
84 | |
85 | dns_cache_item_free(i); | |
86 | } | |
87 | ||
88 | void dns_cache_flush(DnsCache *c) { | |
89 | DnsCacheItem *i; | |
90 | ||
91 | assert(c); | |
92 | ||
7e8e0422 | 93 | while ((i = hashmap_first(c->by_key))) |
322345fd LP |
94 | dns_cache_item_remove_and_free(c, i); |
95 | ||
7e8e0422 LP |
96 | assert(hashmap_size(c->by_key) == 0); |
97 | assert(prioq_size(c->by_expiry) == 0); | |
322345fd | 98 | |
cab5b059 LP |
99 | c->by_key = hashmap_free(c->by_key); |
100 | c->by_expiry = prioq_free(c->by_expiry); | |
322345fd LP |
101 | } |
102 | ||
6b34a6c9 | 103 | static bool dns_cache_remove(DnsCache *c, DnsResourceKey *key) { |
322345fd | 104 | DnsCacheItem *i; |
6b34a6c9 | 105 | bool exist = false; |
322345fd LP |
106 | |
107 | assert(c); | |
108 | assert(key); | |
109 | ||
6b34a6c9 | 110 | while ((i = hashmap_get(c->by_key, key))) { |
322345fd | 111 | dns_cache_item_remove_and_free(c, i); |
6b34a6c9 TG |
112 | exist = true; |
113 | } | |
114 | ||
115 | return exist; | |
322345fd LP |
116 | } |
117 | ||
118 | static void dns_cache_make_space(DnsCache *c, unsigned add) { | |
119 | assert(c); | |
120 | ||
121 | if (add <= 0) | |
122 | return; | |
123 | ||
124 | /* Makes space for n new entries. Note that we actually allow | |
125 | * the cache to grow beyond CACHE_MAX, but only when we shall | |
126 | * add more RRs to the cache than CACHE_MAX at once. In that | |
127 | * case the cache will be emptied completely otherwise. */ | |
128 | ||
129 | for (;;) { | |
faa133f3 | 130 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; |
322345fd LP |
131 | DnsCacheItem *i; |
132 | ||
7e8e0422 | 133 | if (prioq_size(c->by_expiry) <= 0) |
322345fd LP |
134 | break; |
135 | ||
7e8e0422 | 136 | if (prioq_size(c->by_expiry) + add < CACHE_MAX) |
322345fd LP |
137 | break; |
138 | ||
7e8e0422 | 139 | i = prioq_peek(c->by_expiry); |
cbd4560e LP |
140 | assert(i); |
141 | ||
faa133f3 | 142 | /* Take an extra reference to the key so that it |
cbd4560e | 143 | * doesn't go away in the middle of the remove call */ |
7e8e0422 | 144 | key = dns_resource_key_ref(i->key); |
faa133f3 | 145 | dns_cache_remove(c, key); |
322345fd LP |
146 | } |
147 | } | |
148 | ||
149 | void dns_cache_prune(DnsCache *c) { | |
150 | usec_t t = 0; | |
151 | ||
152 | assert(c); | |
153 | ||
154 | /* Remove all entries that are past their TTL */ | |
155 | ||
156 | for (;;) { | |
faa133f3 | 157 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; |
322345fd | 158 | DnsCacheItem *i; |
322345fd | 159 | |
7e8e0422 | 160 | i = prioq_peek(c->by_expiry); |
322345fd LP |
161 | if (!i) |
162 | break; | |
163 | ||
322345fd | 164 | if (t <= 0) |
240b589b | 165 | t = now(clock_boottime_or_monotonic()); |
322345fd | 166 | |
7e8e0422 | 167 | if (i->until > t) |
322345fd LP |
168 | break; |
169 | ||
faa133f3 | 170 | /* Take an extra reference to the key so that it |
cbd4560e | 171 | * doesn't go away in the middle of the remove call */ |
7e8e0422 | 172 | key = dns_resource_key_ref(i->key); |
faa133f3 | 173 | dns_cache_remove(c, key); |
322345fd LP |
174 | } |
175 | } | |
176 | ||
177 | static int dns_cache_item_prioq_compare_func(const void *a, const void *b) { | |
322345fd LP |
178 | const DnsCacheItem *x = a, *y = b; |
179 | ||
7e8e0422 | 180 | if (x->until < y->until) |
322345fd | 181 | return -1; |
7e8e0422 | 182 | if (x->until > y->until) |
322345fd LP |
183 | return 1; |
184 | return 0; | |
185 | } | |
186 | ||
623a4c97 | 187 | static int dns_cache_init(DnsCache *c) { |
7e8e0422 LP |
188 | int r; |
189 | ||
623a4c97 LP |
190 | assert(c); |
191 | ||
7e8e0422 LP |
192 | r = prioq_ensure_allocated(&c->by_expiry, dns_cache_item_prioq_compare_func); |
193 | if (r < 0) | |
194 | return r; | |
195 | ||
d5099efc | 196 | r = hashmap_ensure_allocated(&c->by_key, &dns_resource_key_hash_ops); |
7e8e0422 LP |
197 | if (r < 0) |
198 | return r; | |
199 | ||
200 | return r; | |
201 | } | |
202 | ||
203 | static int dns_cache_link_item(DnsCache *c, DnsCacheItem *i) { | |
204 | DnsCacheItem *first; | |
205 | int r; | |
206 | ||
322345fd LP |
207 | assert(c); |
208 | assert(i); | |
322345fd | 209 | |
7e8e0422 LP |
210 | r = prioq_put(c->by_expiry, i, &i->prioq_idx); |
211 | if (r < 0) | |
212 | return r; | |
322345fd | 213 | |
7e8e0422 LP |
214 | first = hashmap_get(c->by_key, i->key); |
215 | if (first) { | |
216 | LIST_PREPEND(by_key, first, i); | |
217 | assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); | |
218 | } else { | |
219 | r = hashmap_put(c->by_key, i->key, i); | |
220 | if (r < 0) { | |
221 | prioq_remove(c->by_expiry, i, &i->prioq_idx); | |
222 | return r; | |
223 | } | |
322345fd LP |
224 | } |
225 | ||
7e8e0422 | 226 | return 0; |
322345fd LP |
227 | } |
228 | ||
faa133f3 LP |
229 | static DnsCacheItem* dns_cache_get(DnsCache *c, DnsResourceRecord *rr) { |
230 | DnsCacheItem *i; | |
231 | ||
232 | assert(c); | |
233 | assert(rr); | |
234 | ||
7e8e0422 | 235 | LIST_FOREACH(by_key, i, hashmap_get(c->by_key, rr->key)) |
3ef77d04 | 236 | if (i->rr && dns_resource_record_equal(i->rr, rr) > 0) |
faa133f3 LP |
237 | return i; |
238 | ||
239 | return NULL; | |
240 | } | |
241 | ||
931851e8 | 242 | static void dns_cache_item_update_positive(DnsCache *c, DnsCacheItem *i, DnsResourceRecord *rr, bool authenticated, usec_t timestamp) { |
7e8e0422 LP |
243 | assert(c); |
244 | assert(i); | |
245 | assert(rr); | |
246 | ||
247 | i->type = DNS_CACHE_POSITIVE; | |
248 | ||
ece174c5 | 249 | if (!i->by_key_prev) |
7e8e0422 LP |
250 | /* We are the first item in the list, we need to |
251 | * update the key used in the hashmap */ | |
252 | ||
253 | assert_se(hashmap_replace(c->by_key, rr->key, i) >= 0); | |
7e8e0422 LP |
254 | |
255 | dns_resource_record_ref(rr); | |
256 | dns_resource_record_unref(i->rr); | |
257 | i->rr = rr; | |
258 | ||
259 | dns_resource_key_unref(i->key); | |
260 | i->key = dns_resource_key_ref(rr->key); | |
261 | ||
931851e8 | 262 | i->authenticated = authenticated; |
7e8e0422 LP |
263 | i->until = timestamp + MIN(rr->ttl * USEC_PER_SEC, CACHE_TTL_MAX_USEC); |
264 | ||
265 | prioq_reshuffle(c->by_expiry, i, &i->prioq_idx); | |
266 | } | |
267 | ||
a4076574 LP |
268 | static int dns_cache_put_positive( |
269 | DnsCache *c, | |
270 | DnsResourceRecord *rr, | |
931851e8 | 271 | bool authenticated, |
a4076574 LP |
272 | usec_t timestamp, |
273 | int owner_family, | |
274 | const union in_addr_union *owner_address) { | |
275 | ||
322345fd | 276 | _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; |
6b34a6c9 | 277 | _cleanup_free_ char *key_str = NULL; |
7e8e0422 | 278 | DnsCacheItem *existing; |
a257f9d4 | 279 | int r, k; |
322345fd LP |
280 | |
281 | assert(c); | |
282 | assert(rr); | |
a4076574 | 283 | assert(owner_address); |
322345fd LP |
284 | |
285 | /* New TTL is 0? Delete the entry... */ | |
286 | if (rr->ttl <= 0) { | |
a257f9d4 | 287 | k = dns_cache_remove(c, rr->key); |
6b34a6c9 | 288 | |
a257f9d4 TG |
289 | if (log_get_max_level() >= LOG_DEBUG) { |
290 | r = dns_resource_key_to_string(rr->key, &key_str); | |
291 | if (r < 0) | |
292 | return r; | |
293 | ||
294 | if (k > 0) | |
295 | log_debug("Removed zero TTL entry from cache: %s", key_str); | |
296 | else | |
297 | log_debug("Not caching zero TTL cache entry: %s", key_str); | |
298 | } | |
6b34a6c9 | 299 | |
322345fd LP |
300 | return 0; |
301 | } | |
302 | ||
ddf16339 LP |
303 | if (rr->key->class == DNS_CLASS_ANY) |
304 | return 0; | |
c33be4a6 | 305 | if (dns_type_is_pseudo(rr->key->type)) |
ddf16339 LP |
306 | return 0; |
307 | ||
322345fd LP |
308 | /* Entry exists already? Update TTL and timestamp */ |
309 | existing = dns_cache_get(c, rr); | |
310 | if (existing) { | |
931851e8 | 311 | dns_cache_item_update_positive(c, existing, rr, authenticated, timestamp); |
322345fd LP |
312 | return 0; |
313 | } | |
314 | ||
315 | /* Otherwise, add the new RR */ | |
623a4c97 | 316 | r = dns_cache_init(c); |
322345fd LP |
317 | if (r < 0) |
318 | return r; | |
319 | ||
7e8e0422 LP |
320 | dns_cache_make_space(c, 1); |
321 | ||
322 | i = new0(DnsCacheItem, 1); | |
323 | if (!i) | |
324 | return -ENOMEM; | |
325 | ||
326 | i->type = DNS_CACHE_POSITIVE; | |
327 | i->key = dns_resource_key_ref(rr->key); | |
328 | i->rr = dns_resource_record_ref(rr); | |
329 | i->until = timestamp + MIN(i->rr->ttl * USEC_PER_SEC, CACHE_TTL_MAX_USEC); | |
330 | i->prioq_idx = PRIOQ_IDX_NULL; | |
a4076574 LP |
331 | i->owner_family = owner_family; |
332 | i->owner_address = *owner_address; | |
931851e8 | 333 | i->authenticated = authenticated; |
7e8e0422 LP |
334 | |
335 | r = dns_cache_link_item(c, i); | |
336 | if (r < 0) | |
337 | return r; | |
338 | ||
a257f9d4 TG |
339 | if (log_get_max_level() >= LOG_DEBUG) { |
340 | r = dns_resource_key_to_string(i->key, &key_str); | |
341 | if (r < 0) | |
342 | return r; | |
6b34a6c9 | 343 | |
a257f9d4 TG |
344 | log_debug("Added cache entry for %s", key_str); |
345 | } | |
6b34a6c9 | 346 | |
7e8e0422 LP |
347 | i = NULL; |
348 | return 0; | |
349 | } | |
350 | ||
a4076574 LP |
351 | static int dns_cache_put_negative( |
352 | DnsCache *c, | |
353 | DnsResourceKey *key, | |
354 | int rcode, | |
931851e8 | 355 | bool authenticated, |
a4076574 LP |
356 | usec_t timestamp, |
357 | uint32_t soa_ttl, | |
358 | int owner_family, | |
359 | const union in_addr_union *owner_address) { | |
360 | ||
7e8e0422 | 361 | _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; |
6b34a6c9 | 362 | _cleanup_free_ char *key_str = NULL; |
7e8e0422 LP |
363 | int r; |
364 | ||
365 | assert(c); | |
366 | assert(key); | |
a4076574 | 367 | assert(owner_address); |
7e8e0422 LP |
368 | |
369 | dns_cache_remove(c, key); | |
370 | ||
ddf16339 LP |
371 | if (key->class == DNS_CLASS_ANY) |
372 | return 0; | |
c33be4a6 LP |
373 | if (dns_type_is_pseudo(key->type)) |
374 | /* ANY is particularly important to filter out as we | |
375 | * use this as a pseudo-type for NXDOMAIN entries */ | |
ddf16339 | 376 | return 0; |
6b34a6c9 | 377 | if (soa_ttl <= 0) { |
a257f9d4 TG |
378 | if (log_get_max_level() >= LOG_DEBUG) { |
379 | r = dns_resource_key_to_string(key, &key_str); | |
380 | if (r < 0) | |
381 | return r; | |
6b34a6c9 | 382 | |
a257f9d4 TG |
383 | log_debug("Not caching negative entry with zero SOA TTL: %s", key_str); |
384 | } | |
6b34a6c9 | 385 | |
95dd6257 | 386 | return 0; |
6b34a6c9 | 387 | } |
ddf16339 | 388 | |
7e8e0422 LP |
389 | if (!IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) |
390 | return 0; | |
391 | ||
623a4c97 | 392 | r = dns_cache_init(c); |
322345fd LP |
393 | if (r < 0) |
394 | return r; | |
395 | ||
396 | dns_cache_make_space(c, 1); | |
397 | ||
398 | i = new0(DnsCacheItem, 1); | |
399 | if (!i) | |
400 | return -ENOMEM; | |
401 | ||
7e8e0422 | 402 | i->type = rcode == DNS_RCODE_SUCCESS ? DNS_CACHE_NODATA : DNS_CACHE_NXDOMAIN; |
7e8e0422 LP |
403 | i->until = timestamp + MIN(soa_ttl * USEC_PER_SEC, CACHE_TTL_MAX_USEC); |
404 | i->prioq_idx = PRIOQ_IDX_NULL; | |
a4076574 LP |
405 | i->owner_family = owner_family; |
406 | i->owner_address = *owner_address; | |
931851e8 | 407 | i->authenticated = authenticated; |
322345fd | 408 | |
71e13669 TG |
409 | if (i->type == DNS_CACHE_NXDOMAIN) { |
410 | /* NXDOMAIN entries should apply equally to all types, so we use ANY as | |
411 | * a pseudo type for this purpose here. */ | |
412 | i->key = dns_resource_key_new(key->class, DNS_TYPE_ANY, DNS_RESOURCE_KEY_NAME(key)); | |
413 | if (!i->key) | |
414 | return -ENOMEM; | |
415 | } else | |
416 | i->key = dns_resource_key_ref(key); | |
417 | ||
7e8e0422 | 418 | r = dns_cache_link_item(c, i); |
322345fd LP |
419 | if (r < 0) |
420 | return r; | |
421 | ||
a257f9d4 TG |
422 | if (log_get_max_level() >= LOG_DEBUG) { |
423 | r = dns_resource_key_to_string(i->key, &key_str); | |
424 | if (r < 0) | |
425 | return r; | |
6b34a6c9 | 426 | |
a257f9d4 TG |
427 | log_debug("Added %s cache entry for %s", i->type == DNS_CACHE_NODATA ? "NODATA" : "NXDOMAIN", key_str); |
428 | } | |
6b34a6c9 | 429 | |
322345fd | 430 | i = NULL; |
322345fd LP |
431 | return 0; |
432 | } | |
433 | ||
a4076574 LP |
434 | int dns_cache_put( |
435 | DnsCache *c, | |
8e427d9b | 436 | DnsResourceKey *key, |
a4076574 LP |
437 | int rcode, |
438 | DnsAnswer *answer, | |
439 | unsigned max_rrs, | |
931851e8 | 440 | bool authenticated, |
a4076574 LP |
441 | usec_t timestamp, |
442 | int owner_family, | |
443 | const union in_addr_union *owner_address) { | |
444 | ||
02c2857b | 445 | DnsResourceRecord *soa = NULL, *rr; |
eff91ee0 | 446 | unsigned cache_keys, i; |
322345fd LP |
447 | int r; |
448 | ||
449 | assert(c); | |
322345fd | 450 | |
8e427d9b TG |
451 | if (key) { |
452 | /* First, if we were passed a key, delete all matching old RRs, | |
eff91ee0 | 453 | * so that we only keep complete by_key in place. */ |
8e427d9b | 454 | dns_cache_remove(c, key); |
eff91ee0 | 455 | } |
0ec7c46e | 456 | |
c3cb6dc2 | 457 | if (!answer) { |
a257f9d4 TG |
458 | if (log_get_max_level() >= LOG_DEBUG) { |
459 | _cleanup_free_ char *key_str = NULL; | |
c3cb6dc2 | 460 | |
a257f9d4 TG |
461 | r = dns_resource_key_to_string(key, &key_str); |
462 | if (r < 0) | |
463 | return r; | |
c3cb6dc2 | 464 | |
a257f9d4 TG |
465 | log_debug("Not caching negative entry without a SOA record: %s", key_str); |
466 | } | |
c3cb6dc2 | 467 | |
0ec7c46e | 468 | return 0; |
c3cb6dc2 | 469 | } |
0ec7c46e | 470 | |
02c2857b TG |
471 | DNS_ANSWER_FOREACH(rr, answer) |
472 | if (rr->key->cache_flush) | |
473 | dns_cache_remove(c, rr->key); | |
322345fd | 474 | |
7e8e0422 LP |
475 | /* We only care for positive replies and NXDOMAINs, on all |
476 | * other replies we will simply flush the respective entries, | |
477 | * and that's it */ | |
478 | ||
479 | if (!IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) | |
480 | return 0; | |
481 | ||
eff91ee0 DM |
482 | cache_keys = answer->n_rrs; |
483 | ||
8e427d9b TG |
484 | if (key) |
485 | cache_keys ++; | |
eff91ee0 | 486 | |
7e8e0422 | 487 | /* Make some space for our new entries */ |
eff91ee0 | 488 | dns_cache_make_space(c, cache_keys); |
322345fd | 489 | |
7e8e0422 | 490 | if (timestamp <= 0) |
240b589b | 491 | timestamp = now(clock_boottime_or_monotonic()); |
322345fd | 492 | |
7e8e0422 | 493 | /* Second, add in positive entries for all contained RRs */ |
d2f47562 | 494 | for (i = 0; i < MIN(max_rrs, answer->n_rrs); i++) { |
02c2857b | 495 | rr = answer->items[i].rr; |
90325e8c DM |
496 | |
497 | r = dns_cache_put_positive(c, rr, authenticated, timestamp, owner_family, owner_address); | |
7e8e0422 LP |
498 | if (r < 0) |
499 | goto fail; | |
500 | } | |
501 | ||
8e427d9b | 502 | if (!key) |
eff91ee0 DM |
503 | return 0; |
504 | ||
8e427d9b | 505 | /* Third, add in negative entries if the key has no RR */ |
547973de | 506 | r = dns_answer_match_key(answer, key); |
8e427d9b TG |
507 | if (r < 0) |
508 | goto fail; | |
509 | if (r > 0) | |
510 | return 0; | |
7e8e0422 | 511 | |
5d27351f TG |
512 | /* But not if it has a matching CNAME/DNAME (the negative |
513 | * caching will be done on the canonical name, not on the | |
514 | * alias) */ | |
515 | r = dns_answer_find_cname_or_dname(answer, key, NULL); | |
516 | if (r < 0) | |
517 | goto fail; | |
518 | if (r > 0) | |
519 | return 0; | |
520 | ||
547973de LP |
521 | /* See https://tools.ietf.org/html/rfc2308, which say that a |
522 | * matching SOA record in the packet is used to to enable | |
523 | * negative caching. */ | |
0a18f3e5 | 524 | |
8e427d9b TG |
525 | r = dns_answer_find_soa(answer, key, &soa); |
526 | if (r < 0) | |
527 | goto fail; | |
528 | if (r == 0) | |
529 | return 0; | |
7e8e0422 | 530 | |
931851e8 | 531 | r = dns_cache_put_negative(c, key, rcode, authenticated, timestamp, MIN(soa->soa.minimum, soa->ttl), owner_family, owner_address); |
8e427d9b TG |
532 | if (r < 0) |
533 | goto fail; | |
322345fd LP |
534 | |
535 | return 0; | |
536 | ||
537 | fail: | |
538 | /* Adding all RRs failed. Let's clean up what we already | |
539 | * added, just in case */ | |
540 | ||
8e427d9b TG |
541 | if (key) |
542 | dns_cache_remove(c, key); | |
eff91ee0 | 543 | |
7e8e0422 | 544 | for (i = 0; i < answer->n_rrs; i++) |
78c6a153 | 545 | dns_cache_remove(c, answer->items[i].rr->key); |
322345fd LP |
546 | |
547 | return r; | |
548 | } | |
549 | ||
37da8931 | 550 | static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, DnsResourceKey *k) { |
58db254a LP |
551 | DnsCacheItem *i; |
552 | const char *n; | |
553 | int r; | |
5643c00a TG |
554 | |
555 | assert(c); | |
556 | assert(k); | |
557 | ||
58db254a LP |
558 | /* If we hit some OOM error, or suchlike, we don't care too |
559 | * much, after all this is just a cache */ | |
560 | ||
5643c00a | 561 | i = hashmap_get(c->by_key, k); |
d7ce6c94 | 562 | if (i) |
37da8931 LP |
563 | return i; |
564 | ||
565 | n = DNS_RESOURCE_KEY_NAME(k); | |
566 | ||
71e13669 TG |
567 | /* Check if we have an NXDOMAIN cache item for the name, notice that we use |
568 | * the pseudo-type ANY for NXDOMAIN cache items. */ | |
569 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_ANY, n)); | |
570 | if (i && i->type == DNS_CACHE_NXDOMAIN) | |
571 | return i; | |
572 | ||
d7ce6c94 TG |
573 | /* The following record types should never be redirected. See |
574 | * <https://tools.ietf.org/html/rfc4035#section-2.5>. */ | |
575 | if (!IN_SET(k->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME, | |
576 | DNS_TYPE_NSEC3, DNS_TYPE_NSEC, DNS_TYPE_RRSIG, | |
577 | DNS_TYPE_NXT, DNS_TYPE_SIG, DNS_TYPE_KEY)) { | |
578 | /* Check if we have a CNAME record instead */ | |
579 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_CNAME, n)); | |
580 | if (i) | |
581 | return i; | |
5643c00a | 582 | |
d7ce6c94 TG |
583 | /* OK, let's look for cached DNAME records. */ |
584 | for (;;) { | |
585 | char label[DNS_LABEL_MAX]; | |
58db254a | 586 | |
d7ce6c94 TG |
587 | if (isempty(n)) |
588 | return NULL; | |
589 | ||
590 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_DNAME, n)); | |
591 | if (i) | |
592 | return i; | |
58db254a | 593 | |
d7ce6c94 TG |
594 | /* Jump one label ahead */ |
595 | r = dns_label_unescape(&n, label, sizeof(label)); | |
596 | if (r <= 0) | |
597 | return NULL; | |
598 | } | |
599 | } | |
5643c00a | 600 | |
d7ce6c94 TG |
601 | if (k-> type != DNS_TYPE_NSEC) { |
602 | /* Check if we have an NSEC record instead for the name. */ | |
603 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_NSEC, n)); | |
58db254a LP |
604 | if (i) |
605 | return i; | |
58db254a LP |
606 | } |
607 | ||
608 | return NULL; | |
5643c00a TG |
609 | } |
610 | ||
931851e8 | 611 | int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, int *rcode, DnsAnswer **ret, bool *authenticated) { |
faa133f3 | 612 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; |
f52e61da | 613 | unsigned n = 0; |
322345fd | 614 | int r; |
7e8e0422 | 615 | bool nxdomain = false; |
f52e61da | 616 | _cleanup_free_ char *key_str = NULL; |
931851e8 LP |
617 | DnsCacheItem *j, *first, *nsec = NULL; |
618 | bool have_authenticated = false, have_non_authenticated = false; | |
322345fd LP |
619 | |
620 | assert(c); | |
f52e61da | 621 | assert(key); |
623a4c97 | 622 | assert(rcode); |
faa133f3 | 623 | assert(ret); |
931851e8 | 624 | assert(authenticated); |
322345fd | 625 | |
f52e61da LP |
626 | if (key->type == DNS_TYPE_ANY || |
627 | key->class == DNS_CLASS_ANY) { | |
322345fd | 628 | |
931851e8 LP |
629 | /* If we have ANY lookups we don't use the cache, so |
630 | * that the caller refreshes via the network. */ | |
322345fd | 631 | |
a257f9d4 TG |
632 | if (log_get_max_level() >= LOG_DEBUG) { |
633 | r = dns_resource_key_to_string(key, &key_str); | |
634 | if (r < 0) | |
635 | return r; | |
6b34a6c9 | 636 | |
a257f9d4 TG |
637 | log_debug("Ignoring cache for ANY lookup: %s", key_str); |
638 | } | |
6b34a6c9 | 639 | |
f52e61da LP |
640 | *ret = NULL; |
641 | *rcode = DNS_RCODE_SUCCESS; | |
642 | return 0; | |
643 | } | |
6b34a6c9 | 644 | |
37da8931 | 645 | first = dns_cache_get_by_key_follow_cname_dname_nsec(c, key); |
f52e61da LP |
646 | if (!first) { |
647 | /* If one question cannot be answered we need to refresh */ | |
ddf16339 | 648 | |
a257f9d4 TG |
649 | if (log_get_max_level() >= LOG_DEBUG) { |
650 | r = dns_resource_key_to_string(key, &key_str); | |
651 | if (r < 0) | |
652 | return r; | |
6b34a6c9 | 653 | |
a257f9d4 TG |
654 | log_debug("Cache miss for %s", key_str); |
655 | } | |
6b34a6c9 | 656 | |
f52e61da LP |
657 | *ret = NULL; |
658 | *rcode = DNS_RCODE_SUCCESS; | |
659 | return 0; | |
660 | } | |
6b34a6c9 | 661 | |
f52e61da | 662 | LIST_FOREACH(by_key, j, first) { |
37da8931 LP |
663 | if (j->rr) { |
664 | if (j->rr->key->type == DNS_TYPE_NSEC) | |
931851e8 LP |
665 | nsec = j; |
666 | ||
f52e61da | 667 | n++; |
37da8931 | 668 | } else if (j->type == DNS_CACHE_NXDOMAIN) |
f52e61da | 669 | nxdomain = true; |
931851e8 LP |
670 | |
671 | if (j->authenticated) | |
672 | have_authenticated = true; | |
673 | else | |
674 | have_non_authenticated = true; | |
f52e61da | 675 | } |
6b34a6c9 | 676 | |
37da8931 | 677 | if (nsec && key->type != DNS_TYPE_NSEC) { |
a257f9d4 TG |
678 | if (log_get_max_level() >= LOG_DEBUG) { |
679 | r = dns_resource_key_to_string(key, &key_str); | |
680 | if (r < 0) | |
681 | return r; | |
682 | ||
683 | log_debug("NSEC NODATA cache hit for %s", key_str); | |
684 | } | |
37da8931 LP |
685 | |
686 | /* We only found an NSEC record that matches our name. | |
a257f9d4 | 687 | * If it says the type doesn't exist report |
37da8931 LP |
688 | * NODATA. Otherwise report a cache miss. */ |
689 | ||
690 | *ret = NULL; | |
691 | *rcode = DNS_RCODE_SUCCESS; | |
931851e8 | 692 | *authenticated = nsec->authenticated; |
37da8931 | 693 | |
931851e8 LP |
694 | return !bitmap_isset(nsec->rr->nsec.types, key->type) && |
695 | !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_CNAME) && | |
696 | !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_DNAME); | |
37da8931 LP |
697 | } |
698 | ||
a257f9d4 TG |
699 | if (log_get_max_level() >= LOG_DEBUG) { |
700 | r = dns_resource_key_to_string(key, &key_str); | |
701 | if (r < 0) | |
702 | return r; | |
703 | ||
704 | log_debug("%s cache hit for %s", | |
705 | n > 0 ? "Positive" : | |
706 | nxdomain ? "NXDOMAIN" : "NODATA", | |
707 | key_str); | |
708 | } | |
faa133f3 | 709 | |
7e8e0422 LP |
710 | if (n <= 0) { |
711 | *ret = NULL; | |
712 | *rcode = nxdomain ? DNS_RCODE_NXDOMAIN : DNS_RCODE_SUCCESS; | |
931851e8 | 713 | *authenticated = have_authenticated && !have_non_authenticated; |
7e8e0422 LP |
714 | return 1; |
715 | } | |
faa133f3 LP |
716 | |
717 | answer = dns_answer_new(n); | |
718 | if (!answer) | |
719 | return -ENOMEM; | |
322345fd | 720 | |
f52e61da LP |
721 | LIST_FOREACH(by_key, j, first) { |
722 | if (!j->rr) | |
723 | continue; | |
724 | ||
725 | r = dns_answer_add(answer, j->rr, 0); | |
726 | if (r < 0) | |
727 | return r; | |
322345fd LP |
728 | } |
729 | ||
faa133f3 | 730 | *ret = answer; |
7e8e0422 | 731 | *rcode = DNS_RCODE_SUCCESS; |
931851e8 | 732 | *authenticated = have_authenticated && !have_non_authenticated; |
faa133f3 LP |
733 | answer = NULL; |
734 | ||
735 | return n; | |
322345fd | 736 | } |
a4076574 LP |
737 | |
738 | int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_family, const union in_addr_union *owner_address) { | |
739 | DnsCacheItem *i, *first; | |
740 | bool same_owner = true; | |
741 | ||
742 | assert(cache); | |
743 | assert(rr); | |
744 | ||
745 | dns_cache_prune(cache); | |
746 | ||
747 | /* See if there's a cache entry for the same key. If there | |
748 | * isn't there's no conflict */ | |
749 | first = hashmap_get(cache->by_key, rr->key); | |
750 | if (!first) | |
751 | return 0; | |
752 | ||
753 | /* See if the RR key is owned by the same owner, if so, there | |
754 | * isn't a conflict either */ | |
755 | LIST_FOREACH(by_key, i, first) { | |
756 | if (i->owner_family != owner_family || | |
757 | !in_addr_equal(owner_family, &i->owner_address, owner_address)) { | |
758 | same_owner = false; | |
759 | break; | |
760 | } | |
761 | } | |
762 | if (same_owner) | |
763 | return 0; | |
764 | ||
765 | /* See if there's the exact same RR in the cache. If yes, then | |
766 | * there's no conflict. */ | |
767 | if (dns_cache_get(cache, rr)) | |
768 | return 0; | |
769 | ||
770 | /* There's a conflict */ | |
771 | return 1; | |
772 | } | |
4d506d6b | 773 | |
7778dfff DM |
774 | int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p) { |
775 | unsigned ancount = 0; | |
776 | Iterator iterator; | |
777 | DnsCacheItem *i; | |
778 | int r; | |
779 | ||
780 | assert(cache); | |
261f3673 | 781 | assert(p); |
7778dfff DM |
782 | |
783 | HASHMAP_FOREACH(i, cache->by_key, iterator) { | |
784 | DnsCacheItem *j; | |
785 | ||
786 | LIST_FOREACH(by_key, j, i) { | |
7778dfff DM |
787 | if (!j->rr) |
788 | continue; | |
789 | ||
790 | if (!dns_key_is_shared(j->rr->key)) | |
791 | continue; | |
792 | ||
793 | r = dns_packet_append_rr(p, j->rr, NULL, NULL); | |
261f3673 DM |
794 | if (r == -EMSGSIZE && p->protocol == DNS_PROTOCOL_MDNS) { |
795 | /* For mDNS, if we're unable to stuff all known answers into the given packet, | |
796 | * allocate a new one, push the RR into that one and link it to the current one. | |
797 | */ | |
798 | ||
799 | DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); | |
800 | ancount = 0; | |
801 | ||
802 | r = dns_packet_new_query(&p->more, p->protocol, 0, true); | |
803 | if (r < 0) | |
804 | return r; | |
805 | ||
806 | /* continue with new packet */ | |
807 | p = p->more; | |
808 | r = dns_packet_append_rr(p, j->rr, NULL, NULL); | |
809 | } | |
810 | ||
7778dfff DM |
811 | if (r < 0) |
812 | return r; | |
813 | ||
814 | ancount ++; | |
815 | } | |
816 | } | |
817 | ||
818 | DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); | |
819 | ||
820 | return 0; | |
821 | } | |
822 | ||
4d506d6b LP |
823 | void dns_cache_dump(DnsCache *cache, FILE *f) { |
824 | Iterator iterator; | |
825 | DnsCacheItem *i; | |
826 | int r; | |
827 | ||
828 | if (!cache) | |
829 | return; | |
830 | ||
831 | if (!f) | |
832 | f = stdout; | |
833 | ||
834 | HASHMAP_FOREACH(i, cache->by_key, iterator) { | |
835 | DnsCacheItem *j; | |
836 | ||
837 | LIST_FOREACH(by_key, j, i) { | |
838 | _cleanup_free_ char *t = NULL; | |
839 | ||
840 | fputc('\t', f); | |
841 | ||
842 | if (j->rr) { | |
843 | r = dns_resource_record_to_string(j->rr, &t); | |
844 | if (r < 0) { | |
845 | log_oom(); | |
846 | continue; | |
847 | } | |
848 | ||
849 | fputs(t, f); | |
850 | fputc('\n', f); | |
851 | } else { | |
852 | r = dns_resource_key_to_string(j->key, &t); | |
853 | if (r < 0) { | |
854 | log_oom(); | |
855 | continue; | |
856 | } | |
857 | ||
858 | fputs(t, f); | |
859 | fputs(" -- ", f); | |
860 | fputs(j->type == DNS_CACHE_NODATA ? "NODATA" : "NXDOMAIN", f); | |
861 | fputc('\n', f); | |
862 | } | |
863 | } | |
864 | } | |
865 | } | |
866 | ||
867 | bool dns_cache_is_empty(DnsCache *cache) { | |
868 | if (!cache) | |
869 | return true; | |
870 | ||
871 | return hashmap_isempty(cache->by_key); | |
872 | } |