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322345fd LP |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2014 Lennart Poettering | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
18 | ***/ | |
19 | ||
202b76ae ZJS |
20 | #include <net/if.h> |
21 | ||
22 | #include "af-list.h" | |
b5efdb8a | 23 | #include "alloc-util.h" |
58db254a | 24 | #include "dns-domain.h" |
02c2857b | 25 | #include "resolved-dns-answer.h" |
322345fd | 26 | #include "resolved-dns-cache.h" |
7e8e0422 | 27 | #include "resolved-dns-packet.h" |
58db254a | 28 | #include "string-util.h" |
322345fd | 29 | |
6af47493 LP |
30 | /* Never cache more than 4K entries. RFC 1536, Section 5 suggests to |
31 | * leave DNS caches unbounded, but that's crazy. */ | |
d98e5504 | 32 | #define CACHE_MAX 4096 |
cbd4560e | 33 | |
d98e5504 LP |
34 | /* We never keep any item longer than 2h in our cache */ |
35 | #define CACHE_TTL_MAX_USEC (2 * USEC_PER_HOUR) | |
322345fd | 36 | |
201d9958 LP |
37 | /* How long to cache strange rcodes, i.e. rcodes != SUCCESS and != NXDOMAIN (specifically: that's only SERVFAIL for |
38 | * now) */ | |
39 | #define CACHE_TTL_STRANGE_RCODE_USEC (30 * USEC_PER_SEC) | |
40 | ||
623a4c97 LP |
41 | typedef enum DnsCacheItemType DnsCacheItemType; |
42 | typedef struct DnsCacheItem DnsCacheItem; | |
43 | ||
44 | enum DnsCacheItemType { | |
45 | DNS_CACHE_POSITIVE, | |
46 | DNS_CACHE_NODATA, | |
47 | DNS_CACHE_NXDOMAIN, | |
201d9958 | 48 | DNS_CACHE_RCODE, /* "strange" RCODE (effective only SERVFAIL for now) */ |
623a4c97 LP |
49 | }; |
50 | ||
51 | struct DnsCacheItem { | |
d2579eec | 52 | DnsCacheItemType type; |
623a4c97 LP |
53 | DnsResourceKey *key; |
54 | DnsResourceRecord *rr; | |
201d9958 | 55 | int rcode; |
d2579eec | 56 | |
623a4c97 | 57 | usec_t until; |
d2579eec LP |
58 | bool authenticated:1; |
59 | bool shared_owner:1; | |
60 | ||
06d12754 | 61 | int ifindex; |
a4076574 LP |
62 | int owner_family; |
63 | union in_addr_union owner_address; | |
d2579eec LP |
64 | |
65 | unsigned prioq_idx; | |
623a4c97 LP |
66 | LIST_FIELDS(DnsCacheItem, by_key); |
67 | }; | |
68 | ||
201d9958 LP |
69 | static const char *dns_cache_item_type_to_string(DnsCacheItem *item) { |
70 | assert(item); | |
71 | ||
72 | switch (item->type) { | |
73 | ||
74 | case DNS_CACHE_POSITIVE: | |
75 | return "POSITIVE"; | |
76 | ||
77 | case DNS_CACHE_NODATA: | |
78 | return "NODATA"; | |
79 | ||
80 | case DNS_CACHE_NXDOMAIN: | |
81 | return "NXDOMAIN"; | |
82 | ||
83 | case DNS_CACHE_RCODE: | |
84 | return dns_rcode_to_string(item->rcode); | |
85 | } | |
86 | ||
87 | return NULL; | |
88 | } | |
89 | ||
322345fd LP |
90 | static void dns_cache_item_free(DnsCacheItem *i) { |
91 | if (!i) | |
92 | return; | |
93 | ||
94 | dns_resource_record_unref(i->rr); | |
7e8e0422 | 95 | dns_resource_key_unref(i->key); |
322345fd LP |
96 | free(i); |
97 | } | |
98 | ||
99 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsCacheItem*, dns_cache_item_free); | |
100 | ||
39963f11 | 101 | static void dns_cache_item_unlink_and_free(DnsCache *c, DnsCacheItem *i) { |
322345fd LP |
102 | DnsCacheItem *first; |
103 | ||
104 | assert(c); | |
105 | ||
106 | if (!i) | |
107 | return; | |
108 | ||
7e8e0422 LP |
109 | first = hashmap_get(c->by_key, i->key); |
110 | LIST_REMOVE(by_key, first, i); | |
322345fd LP |
111 | |
112 | if (first) | |
7e8e0422 | 113 | assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); |
322345fd | 114 | else |
7e8e0422 | 115 | hashmap_remove(c->by_key, i->key); |
322345fd | 116 | |
7e8e0422 | 117 | prioq_remove(c->by_expiry, i, &i->prioq_idx); |
322345fd LP |
118 | |
119 | dns_cache_item_free(i); | |
120 | } | |
121 | ||
f5bdeb01 LP |
122 | static bool dns_cache_remove_by_rr(DnsCache *c, DnsResourceRecord *rr) { |
123 | DnsCacheItem *first, *i; | |
124 | int r; | |
125 | ||
126 | first = hashmap_get(c->by_key, rr->key); | |
127 | LIST_FOREACH(by_key, i, first) { | |
128 | r = dns_resource_record_equal(i->rr, rr); | |
129 | if (r < 0) | |
130 | return r; | |
131 | if (r > 0) { | |
39963f11 | 132 | dns_cache_item_unlink_and_free(c, i); |
f5bdeb01 LP |
133 | return true; |
134 | } | |
135 | } | |
136 | ||
137 | return false; | |
138 | } | |
139 | ||
2dda578f | 140 | static bool dns_cache_remove_by_key(DnsCache *c, DnsResourceKey *key) { |
1f97052f | 141 | DnsCacheItem *first, *i, *n; |
322345fd LP |
142 | |
143 | assert(c); | |
144 | assert(key); | |
145 | ||
1f97052f LP |
146 | first = hashmap_remove(c->by_key, key); |
147 | if (!first) | |
148 | return false; | |
149 | ||
150 | LIST_FOREACH_SAFE(by_key, i, n, first) { | |
151 | prioq_remove(c->by_expiry, i, &i->prioq_idx); | |
152 | dns_cache_item_free(i); | |
6b34a6c9 TG |
153 | } |
154 | ||
1f97052f | 155 | return true; |
322345fd LP |
156 | } |
157 | ||
ef9a3e3c LP |
158 | void dns_cache_flush(DnsCache *c) { |
159 | DnsResourceKey *key; | |
160 | ||
161 | assert(c); | |
162 | ||
163 | while ((key = hashmap_first_key(c->by_key))) | |
2dda578f | 164 | dns_cache_remove_by_key(c, key); |
ef9a3e3c LP |
165 | |
166 | assert(hashmap_size(c->by_key) == 0); | |
167 | assert(prioq_size(c->by_expiry) == 0); | |
168 | ||
169 | c->by_key = hashmap_free(c->by_key); | |
170 | c->by_expiry = prioq_free(c->by_expiry); | |
171 | } | |
172 | ||
322345fd LP |
173 | static void dns_cache_make_space(DnsCache *c, unsigned add) { |
174 | assert(c); | |
175 | ||
176 | if (add <= 0) | |
177 | return; | |
178 | ||
179 | /* Makes space for n new entries. Note that we actually allow | |
180 | * the cache to grow beyond CACHE_MAX, but only when we shall | |
181 | * add more RRs to the cache than CACHE_MAX at once. In that | |
182 | * case the cache will be emptied completely otherwise. */ | |
183 | ||
184 | for (;;) { | |
faa133f3 | 185 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; |
322345fd LP |
186 | DnsCacheItem *i; |
187 | ||
7e8e0422 | 188 | if (prioq_size(c->by_expiry) <= 0) |
322345fd LP |
189 | break; |
190 | ||
7e8e0422 | 191 | if (prioq_size(c->by_expiry) + add < CACHE_MAX) |
322345fd LP |
192 | break; |
193 | ||
7e8e0422 | 194 | i = prioq_peek(c->by_expiry); |
cbd4560e LP |
195 | assert(i); |
196 | ||
faa133f3 | 197 | /* Take an extra reference to the key so that it |
cbd4560e | 198 | * doesn't go away in the middle of the remove call */ |
7e8e0422 | 199 | key = dns_resource_key_ref(i->key); |
2dda578f | 200 | dns_cache_remove_by_key(c, key); |
322345fd LP |
201 | } |
202 | } | |
203 | ||
204 | void dns_cache_prune(DnsCache *c) { | |
205 | usec_t t = 0; | |
206 | ||
207 | assert(c); | |
208 | ||
209 | /* Remove all entries that are past their TTL */ | |
210 | ||
211 | for (;;) { | |
212 | DnsCacheItem *i; | |
202b76ae | 213 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
322345fd | 214 | |
7e8e0422 | 215 | i = prioq_peek(c->by_expiry); |
322345fd LP |
216 | if (!i) |
217 | break; | |
218 | ||
322345fd | 219 | if (t <= 0) |
240b589b | 220 | t = now(clock_boottime_or_monotonic()); |
322345fd | 221 | |
7e8e0422 | 222 | if (i->until > t) |
322345fd LP |
223 | break; |
224 | ||
d2579eec | 225 | /* Depending whether this is an mDNS shared entry |
202b76ae ZJS |
226 | * either remove only this one RR or the whole RRset */ |
227 | log_debug("Removing %scache entry for %s (expired "USEC_FMT"s ago)", | |
228 | i->shared_owner ? "shared " : "", | |
229 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), | |
230 | (t - i->until) / USEC_PER_SEC); | |
231 | ||
d2579eec | 232 | if (i->shared_owner) |
39963f11 | 233 | dns_cache_item_unlink_and_free(c, i); |
d2579eec LP |
234 | else { |
235 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; | |
236 | ||
237 | /* Take an extra reference to the key so that it | |
238 | * doesn't go away in the middle of the remove call */ | |
239 | key = dns_resource_key_ref(i->key); | |
2dda578f | 240 | dns_cache_remove_by_key(c, key); |
d2579eec | 241 | } |
322345fd LP |
242 | } |
243 | } | |
244 | ||
245 | static int dns_cache_item_prioq_compare_func(const void *a, const void *b) { | |
322345fd LP |
246 | const DnsCacheItem *x = a, *y = b; |
247 | ||
7e8e0422 | 248 | if (x->until < y->until) |
322345fd | 249 | return -1; |
7e8e0422 | 250 | if (x->until > y->until) |
322345fd LP |
251 | return 1; |
252 | return 0; | |
253 | } | |
254 | ||
623a4c97 | 255 | static int dns_cache_init(DnsCache *c) { |
7e8e0422 LP |
256 | int r; |
257 | ||
623a4c97 LP |
258 | assert(c); |
259 | ||
7e8e0422 LP |
260 | r = prioq_ensure_allocated(&c->by_expiry, dns_cache_item_prioq_compare_func); |
261 | if (r < 0) | |
262 | return r; | |
263 | ||
d5099efc | 264 | r = hashmap_ensure_allocated(&c->by_key, &dns_resource_key_hash_ops); |
7e8e0422 LP |
265 | if (r < 0) |
266 | return r; | |
267 | ||
268 | return r; | |
269 | } | |
270 | ||
271 | static int dns_cache_link_item(DnsCache *c, DnsCacheItem *i) { | |
272 | DnsCacheItem *first; | |
273 | int r; | |
274 | ||
322345fd LP |
275 | assert(c); |
276 | assert(i); | |
322345fd | 277 | |
7e8e0422 LP |
278 | r = prioq_put(c->by_expiry, i, &i->prioq_idx); |
279 | if (r < 0) | |
280 | return r; | |
322345fd | 281 | |
7e8e0422 LP |
282 | first = hashmap_get(c->by_key, i->key); |
283 | if (first) { | |
f57e3cd5 LP |
284 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL; |
285 | ||
286 | /* Keep a reference to the original key, while we manipulate the list. */ | |
287 | k = dns_resource_key_ref(first->key); | |
288 | ||
289 | /* Now, try to reduce the number of keys we keep */ | |
290 | dns_resource_key_reduce(&first->key, &i->key); | |
291 | ||
292 | if (first->rr) | |
293 | dns_resource_key_reduce(&first->rr->key, &i->key); | |
294 | if (i->rr) | |
295 | dns_resource_key_reduce(&i->rr->key, &i->key); | |
296 | ||
7e8e0422 LP |
297 | LIST_PREPEND(by_key, first, i); |
298 | assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); | |
299 | } else { | |
300 | r = hashmap_put(c->by_key, i->key, i); | |
301 | if (r < 0) { | |
302 | prioq_remove(c->by_expiry, i, &i->prioq_idx); | |
303 | return r; | |
304 | } | |
322345fd LP |
305 | } |
306 | ||
7e8e0422 | 307 | return 0; |
322345fd LP |
308 | } |
309 | ||
faa133f3 LP |
310 | static DnsCacheItem* dns_cache_get(DnsCache *c, DnsResourceRecord *rr) { |
311 | DnsCacheItem *i; | |
312 | ||
313 | assert(c); | |
314 | assert(rr); | |
315 | ||
7e8e0422 | 316 | LIST_FOREACH(by_key, i, hashmap_get(c->by_key, rr->key)) |
3ef77d04 | 317 | if (i->rr && dns_resource_record_equal(i->rr, rr) > 0) |
faa133f3 LP |
318 | return i; |
319 | ||
320 | return NULL; | |
321 | } | |
322 | ||
d3760be0 | 323 | static usec_t calculate_until(DnsResourceRecord *rr, uint32_t nsec_ttl, usec_t timestamp, bool use_soa_minimum) { |
b211dc7e LP |
324 | uint32_t ttl; |
325 | usec_t u; | |
ee3d6aff LP |
326 | |
327 | assert(rr); | |
328 | ||
d3760be0 | 329 | ttl = MIN(rr->ttl, nsec_ttl); |
b211dc7e LP |
330 | if (rr->key->type == DNS_TYPE_SOA && use_soa_minimum) { |
331 | /* If this is a SOA RR, and it is requested, clamp to | |
332 | * the SOA's minimum field. This is used when we do | |
333 | * negative caching, to determine the TTL for the | |
334 | * negative caching entry. See RFC 2308, Section | |
335 | * 5. */ | |
ee3d6aff | 336 | |
b211dc7e LP |
337 | if (ttl > rr->soa.minimum) |
338 | ttl = rr->soa.minimum; | |
339 | } | |
340 | ||
341 | u = ttl * USEC_PER_SEC; | |
342 | if (u > CACHE_TTL_MAX_USEC) | |
343 | u = CACHE_TTL_MAX_USEC; | |
ee3d6aff LP |
344 | |
345 | if (rr->expiry != USEC_INFINITY) { | |
346 | usec_t left; | |
347 | ||
b211dc7e LP |
348 | /* Make use of the DNSSEC RRSIG expiry info, if we |
349 | * have it */ | |
ee3d6aff LP |
350 | |
351 | left = LESS_BY(rr->expiry, now(CLOCK_REALTIME)); | |
b211dc7e LP |
352 | if (u > left) |
353 | u = left; | |
ee3d6aff LP |
354 | } |
355 | ||
b211dc7e | 356 | return timestamp + u; |
ee3d6aff LP |
357 | } |
358 | ||
d2579eec LP |
359 | static void dns_cache_item_update_positive( |
360 | DnsCache *c, | |
361 | DnsCacheItem *i, | |
362 | DnsResourceRecord *rr, | |
363 | bool authenticated, | |
364 | bool shared_owner, | |
365 | usec_t timestamp, | |
06d12754 | 366 | int ifindex, |
d2579eec LP |
367 | int owner_family, |
368 | const union in_addr_union *owner_address) { | |
369 | ||
7e8e0422 LP |
370 | assert(c); |
371 | assert(i); | |
372 | assert(rr); | |
d2579eec | 373 | assert(owner_address); |
7e8e0422 LP |
374 | |
375 | i->type = DNS_CACHE_POSITIVE; | |
376 | ||
ece174c5 | 377 | if (!i->by_key_prev) |
7e8e0422 LP |
378 | /* We are the first item in the list, we need to |
379 | * update the key used in the hashmap */ | |
380 | ||
381 | assert_se(hashmap_replace(c->by_key, rr->key, i) >= 0); | |
7e8e0422 LP |
382 | |
383 | dns_resource_record_ref(rr); | |
384 | dns_resource_record_unref(i->rr); | |
385 | i->rr = rr; | |
386 | ||
387 | dns_resource_key_unref(i->key); | |
388 | i->key = dns_resource_key_ref(rr->key); | |
389 | ||
d3760be0 | 390 | i->until = calculate_until(rr, (uint32_t) -1, timestamp, false); |
d2579eec LP |
391 | i->authenticated = authenticated; |
392 | i->shared_owner = shared_owner; | |
393 | ||
06d12754 LP |
394 | i->ifindex = ifindex; |
395 | ||
d2579eec LP |
396 | i->owner_family = owner_family; |
397 | i->owner_address = *owner_address; | |
7e8e0422 LP |
398 | |
399 | prioq_reshuffle(c->by_expiry, i, &i->prioq_idx); | |
400 | } | |
401 | ||
a4076574 LP |
402 | static int dns_cache_put_positive( |
403 | DnsCache *c, | |
404 | DnsResourceRecord *rr, | |
931851e8 | 405 | bool authenticated, |
d2579eec | 406 | bool shared_owner, |
a4076574 | 407 | usec_t timestamp, |
06d12754 | 408 | int ifindex, |
a4076574 LP |
409 | int owner_family, |
410 | const union in_addr_union *owner_address) { | |
411 | ||
322345fd | 412 | _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; |
7e8e0422 | 413 | DnsCacheItem *existing; |
202b76ae | 414 | char key_str[DNS_RESOURCE_KEY_STRING_MAX], ifname[IF_NAMESIZE]; |
a257f9d4 | 415 | int r, k; |
322345fd LP |
416 | |
417 | assert(c); | |
418 | assert(rr); | |
a4076574 | 419 | assert(owner_address); |
322345fd | 420 | |
222148b6 LP |
421 | /* Never cache pseudo RRs */ |
422 | if (dns_class_is_pseudo(rr->key->class)) | |
423 | return 0; | |
424 | if (dns_type_is_pseudo(rr->key->type)) | |
425 | return 0; | |
426 | ||
f5bdeb01 | 427 | /* New TTL is 0? Delete this specific entry... */ |
322345fd | 428 | if (rr->ttl <= 0) { |
f5bdeb01 | 429 | k = dns_cache_remove_by_rr(c, rr); |
202b76ae ZJS |
430 | log_debug("%s: %s", |
431 | k > 0 ? "Removed zero TTL entry from cache" : "Not caching zero TTL cache entry", | |
18665d1f | 432 | dns_resource_key_to_string(rr->key, key_str, sizeof key_str)); |
322345fd LP |
433 | return 0; |
434 | } | |
435 | ||
13e785f7 | 436 | /* Entry exists already? Update TTL, timestamp and owner */ |
322345fd LP |
437 | existing = dns_cache_get(c, rr); |
438 | if (existing) { | |
d2579eec LP |
439 | dns_cache_item_update_positive( |
440 | c, | |
441 | existing, | |
442 | rr, | |
443 | authenticated, | |
444 | shared_owner, | |
445 | timestamp, | |
06d12754 | 446 | ifindex, |
d2579eec LP |
447 | owner_family, |
448 | owner_address); | |
322345fd LP |
449 | return 0; |
450 | } | |
451 | ||
452 | /* Otherwise, add the new RR */ | |
623a4c97 | 453 | r = dns_cache_init(c); |
322345fd LP |
454 | if (r < 0) |
455 | return r; | |
456 | ||
7e8e0422 LP |
457 | dns_cache_make_space(c, 1); |
458 | ||
459 | i = new0(DnsCacheItem, 1); | |
460 | if (!i) | |
461 | return -ENOMEM; | |
462 | ||
463 | i->type = DNS_CACHE_POSITIVE; | |
464 | i->key = dns_resource_key_ref(rr->key); | |
465 | i->rr = dns_resource_record_ref(rr); | |
d3760be0 | 466 | i->until = calculate_until(rr, (uint32_t) -1, timestamp, false); |
d2579eec LP |
467 | i->authenticated = authenticated; |
468 | i->shared_owner = shared_owner; | |
06d12754 | 469 | i->ifindex = ifindex; |
a4076574 LP |
470 | i->owner_family = owner_family; |
471 | i->owner_address = *owner_address; | |
d2579eec | 472 | i->prioq_idx = PRIOQ_IDX_NULL; |
7e8e0422 LP |
473 | |
474 | r = dns_cache_link_item(c, i); | |
475 | if (r < 0) | |
476 | return r; | |
477 | ||
a257f9d4 | 478 | if (log_get_max_level() >= LOG_DEBUG) { |
202b76ae ZJS |
479 | _cleanup_free_ char *t = NULL; |
480 | ||
481 | (void) in_addr_to_string(i->owner_family, &i->owner_address, &t); | |
482 | ||
483 | log_debug("Added positive %s%s cache entry for %s "USEC_FMT"s on %s/%s/%s", | |
484 | i->authenticated ? "authenticated" : "unauthenticated", | |
485 | i->shared_owner ? " shared" : "", | |
486 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), | |
487 | (i->until - timestamp) / USEC_PER_SEC, | |
488 | i->ifindex == 0 ? "*" : strna(if_indextoname(i->ifindex, ifname)), | |
489 | af_to_name_short(i->owner_family), | |
490 | strna(t)); | |
a257f9d4 | 491 | } |
6b34a6c9 | 492 | |
7e8e0422 LP |
493 | i = NULL; |
494 | return 0; | |
495 | } | |
496 | ||
a4076574 LP |
497 | static int dns_cache_put_negative( |
498 | DnsCache *c, | |
499 | DnsResourceKey *key, | |
500 | int rcode, | |
931851e8 | 501 | bool authenticated, |
d3760be0 | 502 | uint32_t nsec_ttl, |
a4076574 | 503 | usec_t timestamp, |
b211dc7e | 504 | DnsResourceRecord *soa, |
a4076574 LP |
505 | int owner_family, |
506 | const union in_addr_union *owner_address) { | |
507 | ||
7e8e0422 | 508 | _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; |
202b76ae | 509 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
7e8e0422 LP |
510 | int r; |
511 | ||
512 | assert(c); | |
513 | assert(key); | |
a4076574 | 514 | assert(owner_address); |
7e8e0422 | 515 | |
98b6be77 LP |
516 | /* Never cache pseudo RR keys. DNS_TYPE_ANY is particularly |
517 | * important to filter out as we use this as a pseudo-type for | |
518 | * NXDOMAIN entries */ | |
222148b6 | 519 | if (dns_class_is_pseudo(key->class)) |
ddf16339 | 520 | return 0; |
c33be4a6 | 521 | if (dns_type_is_pseudo(key->type)) |
ddf16339 | 522 | return 0; |
222148b6 | 523 | |
201d9958 LP |
524 | if (IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) { |
525 | if (!soa) | |
526 | return 0; | |
ddf16339 | 527 | |
201d9958 LP |
528 | /* For negative replies, check if we have a TTL of a SOA */ |
529 | if (nsec_ttl <= 0 || soa->soa.minimum <= 0 || soa->ttl <= 0) { | |
530 | log_debug("Not caching negative entry with zero SOA/NSEC/NSEC3 TTL: %s", | |
531 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
532 | return 0; | |
533 | } | |
534 | } else if (rcode != DNS_RCODE_SERVFAIL) | |
7e8e0422 LP |
535 | return 0; |
536 | ||
623a4c97 | 537 | r = dns_cache_init(c); |
322345fd LP |
538 | if (r < 0) |
539 | return r; | |
540 | ||
541 | dns_cache_make_space(c, 1); | |
542 | ||
543 | i = new0(DnsCacheItem, 1); | |
544 | if (!i) | |
545 | return -ENOMEM; | |
546 | ||
201d9958 LP |
547 | i->type = |
548 | rcode == DNS_RCODE_SUCCESS ? DNS_CACHE_NODATA : | |
549 | rcode == DNS_RCODE_NXDOMAIN ? DNS_CACHE_NXDOMAIN : DNS_CACHE_RCODE; | |
550 | i->until = | |
551 | i->type == DNS_CACHE_RCODE ? timestamp + CACHE_TTL_STRANGE_RCODE_USEC : | |
552 | calculate_until(soa, nsec_ttl, timestamp, true); | |
d2579eec | 553 | i->authenticated = authenticated; |
a4076574 LP |
554 | i->owner_family = owner_family; |
555 | i->owner_address = *owner_address; | |
d2579eec | 556 | i->prioq_idx = PRIOQ_IDX_NULL; |
201d9958 | 557 | i->rcode = rcode; |
322345fd | 558 | |
71e13669 TG |
559 | if (i->type == DNS_CACHE_NXDOMAIN) { |
560 | /* NXDOMAIN entries should apply equally to all types, so we use ANY as | |
561 | * a pseudo type for this purpose here. */ | |
1c02e7ba | 562 | i->key = dns_resource_key_new(key->class, DNS_TYPE_ANY, dns_resource_key_name(key)); |
71e13669 TG |
563 | if (!i->key) |
564 | return -ENOMEM; | |
a5444ca9 LP |
565 | |
566 | /* Make sure to remove any previous entry for this | |
567 | * specific ANY key. (For non-ANY keys the cache data | |
568 | * is already cleared by the caller.) Note that we | |
569 | * don't bother removing positive or NODATA cache | |
570 | * items in this case, because it would either be slow | |
571 | * or require explicit indexing by name */ | |
572 | dns_cache_remove_by_key(c, key); | |
71e13669 TG |
573 | } else |
574 | i->key = dns_resource_key_ref(key); | |
575 | ||
7e8e0422 | 576 | r = dns_cache_link_item(c, i); |
322345fd LP |
577 | if (r < 0) |
578 | return r; | |
579 | ||
202b76ae | 580 | log_debug("Added %s cache entry for %s "USEC_FMT"s", |
201d9958 | 581 | dns_cache_item_type_to_string(i), |
202b76ae ZJS |
582 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), |
583 | (i->until - timestamp) / USEC_PER_SEC); | |
6b34a6c9 | 584 | |
322345fd | 585 | i = NULL; |
322345fd LP |
586 | return 0; |
587 | } | |
588 | ||
d2579eec LP |
589 | static void dns_cache_remove_previous( |
590 | DnsCache *c, | |
591 | DnsResourceKey *key, | |
592 | DnsAnswer *answer) { | |
593 | ||
594 | DnsResourceRecord *rr; | |
595 | DnsAnswerFlags flags; | |
596 | ||
597 | assert(c); | |
598 | ||
599 | /* First, if we were passed a key (i.e. on LLMNR/DNS, but | |
600 | * not on mDNS), delete all matching old RRs, so that we only | |
601 | * keep complete by_key in place. */ | |
602 | if (key) | |
2dda578f | 603 | dns_cache_remove_by_key(c, key); |
d2579eec LP |
604 | |
605 | /* Second, flush all entries matching the answer, unless this | |
606 | * is an RR that is explicitly marked to be "shared" between | |
607 | * peers (i.e. mDNS RRs without the flush-cache bit set). */ | |
608 | DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { | |
609 | if ((flags & DNS_ANSWER_CACHEABLE) == 0) | |
610 | continue; | |
611 | ||
612 | if (flags & DNS_ANSWER_SHARED_OWNER) | |
613 | continue; | |
614 | ||
2dda578f | 615 | dns_cache_remove_by_key(c, rr->key); |
d2579eec LP |
616 | } |
617 | } | |
618 | ||
f6618dcd LP |
619 | static bool rr_eligible(DnsResourceRecord *rr) { |
620 | assert(rr); | |
621 | ||
622 | /* When we see an NSEC/NSEC3 RR, we'll only cache it if it is from the lower zone, not the upper zone, since | |
623 | * that's where the interesting bits are (with exception of DS RRs). Of course, this way we cannot derive DS | |
624 | * existence from any cached NSEC/NSEC3, but that should be fine. */ | |
625 | ||
626 | switch (rr->key->type) { | |
627 | ||
628 | case DNS_TYPE_NSEC: | |
629 | return !bitmap_isset(rr->nsec.types, DNS_TYPE_NS) || | |
630 | bitmap_isset(rr->nsec.types, DNS_TYPE_SOA); | |
631 | ||
632 | case DNS_TYPE_NSEC3: | |
633 | return !bitmap_isset(rr->nsec3.types, DNS_TYPE_NS) || | |
634 | bitmap_isset(rr->nsec3.types, DNS_TYPE_SOA); | |
635 | ||
636 | default: | |
637 | return true; | |
638 | } | |
639 | } | |
640 | ||
a4076574 LP |
641 | int dns_cache_put( |
642 | DnsCache *c, | |
8e427d9b | 643 | DnsResourceKey *key, |
a4076574 LP |
644 | int rcode, |
645 | DnsAnswer *answer, | |
931851e8 | 646 | bool authenticated, |
d3760be0 | 647 | uint32_t nsec_ttl, |
a4076574 LP |
648 | usec_t timestamp, |
649 | int owner_family, | |
650 | const union in_addr_union *owner_address) { | |
651 | ||
02c2857b | 652 | DnsResourceRecord *soa = NULL, *rr; |
201d9958 | 653 | bool weird_rcode = false; |
105e1512 LP |
654 | DnsAnswerFlags flags; |
655 | unsigned cache_keys; | |
06d12754 | 656 | int r, ifindex; |
322345fd LP |
657 | |
658 | assert(c); | |
d2579eec | 659 | assert(owner_address); |
322345fd | 660 | |
d2579eec | 661 | dns_cache_remove_previous(c, key, answer); |
0ec7c46e | 662 | |
201d9958 LP |
663 | /* We only care for positive replies and NXDOMAINs, on all other replies we will simply flush the respective |
664 | * entries, and that's it. (Well, with one further exception: since some DNS zones (akamai!) return SERVFAIL | |
665 | * consistently for some lookups, and forwarders tend to propagate that we'll cache that too, but only for a | |
666 | * short time.) */ | |
6ff01a0d | 667 | |
201d9958 | 668 | if (IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) { |
c3cb6dc2 | 669 | |
201d9958 LP |
670 | if (dns_answer_size(answer) <= 0) { |
671 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; | |
672 | ||
673 | log_debug("Not caching negative entry without a SOA record: %s", | |
674 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
675 | return 0; | |
676 | } | |
677 | ||
678 | } else { | |
679 | /* Only cache SERVFAIL as "weird" rcode for now. We can add more later, should that turn out to be | |
680 | * beneficial. */ | |
681 | if (rcode != DNS_RCODE_SERVFAIL) | |
682 | return 0; | |
683 | ||
684 | weird_rcode = true; | |
c3cb6dc2 | 685 | } |
0ec7c46e | 686 | |
ea207b63 | 687 | cache_keys = dns_answer_size(answer); |
8e427d9b | 688 | if (key) |
313cefa1 | 689 | cache_keys++; |
eff91ee0 | 690 | |
7e8e0422 | 691 | /* Make some space for our new entries */ |
eff91ee0 | 692 | dns_cache_make_space(c, cache_keys); |
322345fd | 693 | |
7e8e0422 | 694 | if (timestamp <= 0) |
240b589b | 695 | timestamp = now(clock_boottime_or_monotonic()); |
322345fd | 696 | |
7e8e0422 | 697 | /* Second, add in positive entries for all contained RRs */ |
06d12754 | 698 | DNS_ANSWER_FOREACH_FULL(rr, ifindex, flags, answer) { |
105e1512 LP |
699 | if ((flags & DNS_ANSWER_CACHEABLE) == 0) |
700 | continue; | |
701 | ||
f6618dcd LP |
702 | r = rr_eligible(rr); |
703 | if (r < 0) | |
704 | return r; | |
705 | if (r == 0) | |
706 | continue; | |
707 | ||
d2579eec LP |
708 | r = dns_cache_put_positive( |
709 | c, | |
710 | rr, | |
711 | flags & DNS_ANSWER_AUTHENTICATED, | |
712 | flags & DNS_ANSWER_SHARED_OWNER, | |
713 | timestamp, | |
06d12754 | 714 | ifindex, |
d2579eec | 715 | owner_family, owner_address); |
7e8e0422 LP |
716 | if (r < 0) |
717 | goto fail; | |
718 | } | |
719 | ||
d2579eec | 720 | if (!key) /* mDNS doesn't know negative caching, really */ |
eff91ee0 DM |
721 | return 0; |
722 | ||
8e427d9b | 723 | /* Third, add in negative entries if the key has no RR */ |
105e1512 | 724 | r = dns_answer_match_key(answer, key, NULL); |
8e427d9b TG |
725 | if (r < 0) |
726 | goto fail; | |
727 | if (r > 0) | |
728 | return 0; | |
7e8e0422 | 729 | |
5d27351f TG |
730 | /* But not if it has a matching CNAME/DNAME (the negative |
731 | * caching will be done on the canonical name, not on the | |
732 | * alias) */ | |
105e1512 | 733 | r = dns_answer_find_cname_or_dname(answer, key, NULL, NULL); |
5d27351f TG |
734 | if (r < 0) |
735 | goto fail; | |
736 | if (r > 0) | |
737 | return 0; | |
738 | ||
201d9958 LP |
739 | /* See https://tools.ietf.org/html/rfc2308, which say that a matching SOA record in the packet is used to |
740 | * enable negative caching. We apply one exception though: if we are about to cache a weird rcode we do so | |
741 | * regardless of a SOA. */ | |
fd009cd8 | 742 | r = dns_answer_find_soa(answer, key, &soa, &flags); |
8e427d9b TG |
743 | if (r < 0) |
744 | goto fail; | |
201d9958 | 745 | if (r == 0 && !weird_rcode) |
fd009cd8 | 746 | return 0; |
201d9958 LP |
747 | if (r > 0) { |
748 | /* Refuse using the SOA data if it is unsigned, but the key is | |
749 | * signed */ | |
750 | if (authenticated && (flags & DNS_ANSWER_AUTHENTICATED) == 0) | |
751 | return 0; | |
752 | } | |
fd009cd8 | 753 | |
d2579eec LP |
754 | r = dns_cache_put_negative( |
755 | c, | |
756 | key, | |
757 | rcode, | |
758 | authenticated, | |
d3760be0 | 759 | nsec_ttl, |
d2579eec | 760 | timestamp, |
b211dc7e | 761 | soa, |
d2579eec | 762 | owner_family, owner_address); |
8e427d9b TG |
763 | if (r < 0) |
764 | goto fail; | |
322345fd LP |
765 | |
766 | return 0; | |
767 | ||
768 | fail: | |
769 | /* Adding all RRs failed. Let's clean up what we already | |
770 | * added, just in case */ | |
771 | ||
8e427d9b | 772 | if (key) |
2dda578f | 773 | dns_cache_remove_by_key(c, key); |
eff91ee0 | 774 | |
105e1512 LP |
775 | DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { |
776 | if ((flags & DNS_ANSWER_CACHEABLE) == 0) | |
777 | continue; | |
778 | ||
2dda578f | 779 | dns_cache_remove_by_key(c, rr->key); |
105e1512 | 780 | } |
322345fd LP |
781 | |
782 | return r; | |
783 | } | |
784 | ||
37da8931 | 785 | static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, DnsResourceKey *k) { |
58db254a LP |
786 | DnsCacheItem *i; |
787 | const char *n; | |
788 | int r; | |
5643c00a TG |
789 | |
790 | assert(c); | |
791 | assert(k); | |
792 | ||
58db254a LP |
793 | /* If we hit some OOM error, or suchlike, we don't care too |
794 | * much, after all this is just a cache */ | |
795 | ||
5643c00a | 796 | i = hashmap_get(c->by_key, k); |
d7ce6c94 | 797 | if (i) |
37da8931 LP |
798 | return i; |
799 | ||
1c02e7ba | 800 | n = dns_resource_key_name(k); |
37da8931 | 801 | |
71e13669 TG |
802 | /* Check if we have an NXDOMAIN cache item for the name, notice that we use |
803 | * the pseudo-type ANY for NXDOMAIN cache items. */ | |
804 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_ANY, n)); | |
805 | if (i && i->type == DNS_CACHE_NXDOMAIN) | |
806 | return i; | |
807 | ||
d3c7e913 | 808 | if (dns_type_may_redirect(k->type)) { |
d7ce6c94 TG |
809 | /* Check if we have a CNAME record instead */ |
810 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_CNAME, n)); | |
811 | if (i) | |
812 | return i; | |
5643c00a | 813 | |
d7ce6c94 TG |
814 | /* OK, let's look for cached DNAME records. */ |
815 | for (;;) { | |
d7ce6c94 TG |
816 | if (isempty(n)) |
817 | return NULL; | |
818 | ||
819 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_DNAME, n)); | |
820 | if (i) | |
821 | return i; | |
58db254a | 822 | |
d7ce6c94 | 823 | /* Jump one label ahead */ |
950b692b | 824 | r = dns_name_parent(&n); |
d7ce6c94 TG |
825 | if (r <= 0) |
826 | return NULL; | |
827 | } | |
828 | } | |
5643c00a | 829 | |
950b692b | 830 | if (k->type != DNS_TYPE_NSEC) { |
d7ce6c94 TG |
831 | /* Check if we have an NSEC record instead for the name. */ |
832 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_NSEC, n)); | |
58db254a LP |
833 | if (i) |
834 | return i; | |
58db254a LP |
835 | } |
836 | ||
837 | return NULL; | |
5643c00a TG |
838 | } |
839 | ||
17c8de63 | 840 | int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, bool clamp_ttl, int *rcode, DnsAnswer **ret, bool *authenticated) { |
faa133f3 | 841 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; |
202b76ae | 842 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
f52e61da | 843 | unsigned n = 0; |
322345fd | 844 | int r; |
7e8e0422 | 845 | bool nxdomain = false; |
931851e8 LP |
846 | DnsCacheItem *j, *first, *nsec = NULL; |
847 | bool have_authenticated = false, have_non_authenticated = false; | |
17c8de63 | 848 | usec_t current; |
201d9958 | 849 | int found_rcode = -1; |
322345fd LP |
850 | |
851 | assert(c); | |
f52e61da | 852 | assert(key); |
623a4c97 | 853 | assert(rcode); |
faa133f3 | 854 | assert(ret); |
931851e8 | 855 | assert(authenticated); |
322345fd | 856 | |
202b76ae | 857 | if (key->type == DNS_TYPE_ANY || key->class == DNS_CLASS_ANY) { |
931851e8 LP |
858 | /* If we have ANY lookups we don't use the cache, so |
859 | * that the caller refreshes via the network. */ | |
322345fd | 860 | |
202b76ae ZJS |
861 | log_debug("Ignoring cache for ANY lookup: %s", |
862 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
6b34a6c9 | 863 | |
a150ff5e LP |
864 | c->n_miss++; |
865 | ||
f52e61da LP |
866 | *ret = NULL; |
867 | *rcode = DNS_RCODE_SUCCESS; | |
2d4a4e14 LP |
868 | *authenticated = false; |
869 | ||
f52e61da LP |
870 | return 0; |
871 | } | |
6b34a6c9 | 872 | |
37da8931 | 873 | first = dns_cache_get_by_key_follow_cname_dname_nsec(c, key); |
f52e61da LP |
874 | if (!first) { |
875 | /* If one question cannot be answered we need to refresh */ | |
ddf16339 | 876 | |
202b76ae ZJS |
877 | log_debug("Cache miss for %s", |
878 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
6b34a6c9 | 879 | |
a150ff5e LP |
880 | c->n_miss++; |
881 | ||
f52e61da LP |
882 | *ret = NULL; |
883 | *rcode = DNS_RCODE_SUCCESS; | |
2d4a4e14 LP |
884 | *authenticated = false; |
885 | ||
f52e61da LP |
886 | return 0; |
887 | } | |
6b34a6c9 | 888 | |
f52e61da | 889 | LIST_FOREACH(by_key, j, first) { |
37da8931 LP |
890 | if (j->rr) { |
891 | if (j->rr->key->type == DNS_TYPE_NSEC) | |
931851e8 LP |
892 | nsec = j; |
893 | ||
f52e61da | 894 | n++; |
37da8931 | 895 | } else if (j->type == DNS_CACHE_NXDOMAIN) |
f52e61da | 896 | nxdomain = true; |
201d9958 LP |
897 | else if (j->type == DNS_CACHE_RCODE) |
898 | found_rcode = j->rcode; | |
931851e8 LP |
899 | |
900 | if (j->authenticated) | |
901 | have_authenticated = true; | |
902 | else | |
903 | have_non_authenticated = true; | |
f52e61da | 904 | } |
6b34a6c9 | 905 | |
201d9958 LP |
906 | if (found_rcode >= 0) { |
907 | log_debug("RCODE %s cache hit for %s", | |
908 | dns_rcode_to_string(found_rcode), | |
909 | dns_resource_key_to_string(key, key_str, sizeof(key_str))); | |
910 | ||
911 | *ret = NULL; | |
912 | *rcode = found_rcode; | |
913 | *authenticated = false; | |
914 | ||
915 | c->n_hit++; | |
916 | return 1; | |
917 | } | |
918 | ||
f6618dcd LP |
919 | if (nsec && !IN_SET(key->type, DNS_TYPE_NSEC, DNS_TYPE_DS)) { |
920 | /* Note that we won't derive information for DS RRs from an NSEC, because we only cache NSEC RRs from | |
921 | * the lower-zone of a zone cut, but the DS RRs are on the upper zone. */ | |
922 | ||
202b76ae ZJS |
923 | log_debug("NSEC NODATA cache hit for %s", |
924 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
37da8931 LP |
925 | |
926 | /* We only found an NSEC record that matches our name. | |
a257f9d4 | 927 | * If it says the type doesn't exist report |
37da8931 LP |
928 | * NODATA. Otherwise report a cache miss. */ |
929 | ||
930 | *ret = NULL; | |
931 | *rcode = DNS_RCODE_SUCCESS; | |
931851e8 | 932 | *authenticated = nsec->authenticated; |
37da8931 | 933 | |
a150ff5e LP |
934 | if (!bitmap_isset(nsec->rr->nsec.types, key->type) && |
935 | !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_CNAME) && | |
936 | !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_DNAME)) { | |
937 | c->n_hit++; | |
938 | return 1; | |
939 | } | |
940 | ||
941 | c->n_miss++; | |
942 | return 0; | |
37da8931 LP |
943 | } |
944 | ||
202b76ae ZJS |
945 | log_debug("%s cache hit for %s", |
946 | n > 0 ? "Positive" : | |
947 | nxdomain ? "NXDOMAIN" : "NODATA", | |
948 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
faa133f3 | 949 | |
7e8e0422 | 950 | if (n <= 0) { |
a150ff5e LP |
951 | c->n_hit++; |
952 | ||
7e8e0422 LP |
953 | *ret = NULL; |
954 | *rcode = nxdomain ? DNS_RCODE_NXDOMAIN : DNS_RCODE_SUCCESS; | |
931851e8 | 955 | *authenticated = have_authenticated && !have_non_authenticated; |
7e8e0422 LP |
956 | return 1; |
957 | } | |
faa133f3 LP |
958 | |
959 | answer = dns_answer_new(n); | |
960 | if (!answer) | |
961 | return -ENOMEM; | |
322345fd | 962 | |
17c8de63 LP |
963 | if (clamp_ttl) |
964 | current = now(clock_boottime_or_monotonic()); | |
965 | ||
f52e61da | 966 | LIST_FOREACH(by_key, j, first) { |
17c8de63 LP |
967 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; |
968 | ||
f52e61da LP |
969 | if (!j->rr) |
970 | continue; | |
971 | ||
17c8de63 LP |
972 | if (clamp_ttl) { |
973 | rr = dns_resource_record_ref(j->rr); | |
974 | ||
975 | r = dns_resource_record_clamp_ttl(&rr, LESS_BY(j->until, current) / USEC_PER_SEC); | |
976 | if (r < 0) | |
977 | return r; | |
978 | } | |
979 | ||
980 | r = dns_answer_add(answer, rr ?: j->rr, j->ifindex, j->authenticated ? DNS_ANSWER_AUTHENTICATED : 0); | |
f52e61da LP |
981 | if (r < 0) |
982 | return r; | |
322345fd LP |
983 | } |
984 | ||
a150ff5e LP |
985 | c->n_hit++; |
986 | ||
faa133f3 | 987 | *ret = answer; |
7e8e0422 | 988 | *rcode = DNS_RCODE_SUCCESS; |
931851e8 | 989 | *authenticated = have_authenticated && !have_non_authenticated; |
faa133f3 LP |
990 | answer = NULL; |
991 | ||
992 | return n; | |
322345fd | 993 | } |
a4076574 LP |
994 | |
995 | int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_family, const union in_addr_union *owner_address) { | |
996 | DnsCacheItem *i, *first; | |
997 | bool same_owner = true; | |
998 | ||
999 | assert(cache); | |
1000 | assert(rr); | |
1001 | ||
1002 | dns_cache_prune(cache); | |
1003 | ||
1004 | /* See if there's a cache entry for the same key. If there | |
1005 | * isn't there's no conflict */ | |
1006 | first = hashmap_get(cache->by_key, rr->key); | |
1007 | if (!first) | |
1008 | return 0; | |
1009 | ||
1010 | /* See if the RR key is owned by the same owner, if so, there | |
1011 | * isn't a conflict either */ | |
1012 | LIST_FOREACH(by_key, i, first) { | |
1013 | if (i->owner_family != owner_family || | |
1014 | !in_addr_equal(owner_family, &i->owner_address, owner_address)) { | |
1015 | same_owner = false; | |
1016 | break; | |
1017 | } | |
1018 | } | |
1019 | if (same_owner) | |
1020 | return 0; | |
1021 | ||
1022 | /* See if there's the exact same RR in the cache. If yes, then | |
1023 | * there's no conflict. */ | |
1024 | if (dns_cache_get(cache, rr)) | |
1025 | return 0; | |
1026 | ||
1027 | /* There's a conflict */ | |
1028 | return 1; | |
1029 | } | |
4d506d6b | 1030 | |
7778dfff DM |
1031 | int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p) { |
1032 | unsigned ancount = 0; | |
1033 | Iterator iterator; | |
1034 | DnsCacheItem *i; | |
1035 | int r; | |
1036 | ||
1037 | assert(cache); | |
261f3673 | 1038 | assert(p); |
7778dfff DM |
1039 | |
1040 | HASHMAP_FOREACH(i, cache->by_key, iterator) { | |
1041 | DnsCacheItem *j; | |
1042 | ||
1043 | LIST_FOREACH(by_key, j, i) { | |
7778dfff DM |
1044 | if (!j->rr) |
1045 | continue; | |
1046 | ||
d2579eec | 1047 | if (!j->shared_owner) |
7778dfff DM |
1048 | continue; |
1049 | ||
58ab31d5 | 1050 | r = dns_packet_append_rr(p, j->rr, 0, NULL, NULL); |
261f3673 DM |
1051 | if (r == -EMSGSIZE && p->protocol == DNS_PROTOCOL_MDNS) { |
1052 | /* For mDNS, if we're unable to stuff all known answers into the given packet, | |
1053 | * allocate a new one, push the RR into that one and link it to the current one. | |
1054 | */ | |
1055 | ||
1056 | DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); | |
1057 | ancount = 0; | |
1058 | ||
1059 | r = dns_packet_new_query(&p->more, p->protocol, 0, true); | |
1060 | if (r < 0) | |
1061 | return r; | |
1062 | ||
1063 | /* continue with new packet */ | |
1064 | p = p->more; | |
58ab31d5 | 1065 | r = dns_packet_append_rr(p, j->rr, 0, NULL, NULL); |
261f3673 DM |
1066 | } |
1067 | ||
7778dfff DM |
1068 | if (r < 0) |
1069 | return r; | |
1070 | ||
313cefa1 | 1071 | ancount++; |
7778dfff DM |
1072 | } |
1073 | } | |
1074 | ||
1075 | DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); | |
1076 | ||
1077 | return 0; | |
1078 | } | |
1079 | ||
4d506d6b LP |
1080 | void dns_cache_dump(DnsCache *cache, FILE *f) { |
1081 | Iterator iterator; | |
1082 | DnsCacheItem *i; | |
4d506d6b LP |
1083 | |
1084 | if (!cache) | |
1085 | return; | |
1086 | ||
1087 | if (!f) | |
1088 | f = stdout; | |
1089 | ||
1090 | HASHMAP_FOREACH(i, cache->by_key, iterator) { | |
1091 | DnsCacheItem *j; | |
1092 | ||
1093 | LIST_FOREACH(by_key, j, i) { | |
4d506d6b LP |
1094 | |
1095 | fputc('\t', f); | |
1096 | ||
1097 | if (j->rr) { | |
7b50eb2e LP |
1098 | const char *t; |
1099 | t = dns_resource_record_to_string(j->rr); | |
1100 | if (!t) { | |
4d506d6b LP |
1101 | log_oom(); |
1102 | continue; | |
1103 | } | |
1104 | ||
1105 | fputs(t, f); | |
1106 | fputc('\n', f); | |
1107 | } else { | |
202b76ae | 1108 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
4d506d6b | 1109 | |
202b76ae | 1110 | fputs(dns_resource_key_to_string(j->key, key_str, sizeof key_str), f); |
4d506d6b | 1111 | fputs(" -- ", f); |
201d9958 | 1112 | fputs(dns_cache_item_type_to_string(j), f); |
4d506d6b LP |
1113 | fputc('\n', f); |
1114 | } | |
1115 | } | |
1116 | } | |
1117 | } | |
1118 | ||
1119 | bool dns_cache_is_empty(DnsCache *cache) { | |
1120 | if (!cache) | |
1121 | return true; | |
1122 | ||
1123 | return hashmap_isempty(cache->by_key); | |
1124 | } | |
a150ff5e LP |
1125 | |
1126 | unsigned dns_cache_size(DnsCache *cache) { | |
1127 | if (!cache) | |
1128 | return 0; | |
1129 | ||
1130 | return hashmap_size(cache->by_key); | |
1131 | } |