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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
322345fd | 2 | |
202b76ae ZJS |
3 | #include <net/if.h> |
4 | ||
5 | #include "af-list.h" | |
b5efdb8a | 6 | #include "alloc-util.h" |
58db254a | 7 | #include "dns-domain.h" |
518a66ec | 8 | #include "format-util.h" |
02c2857b | 9 | #include "resolved-dns-answer.h" |
322345fd | 10 | #include "resolved-dns-cache.h" |
7e8e0422 | 11 | #include "resolved-dns-packet.h" |
58db254a | 12 | #include "string-util.h" |
322345fd | 13 | |
6af47493 LP |
14 | /* Never cache more than 4K entries. RFC 1536, Section 5 suggests to |
15 | * leave DNS caches unbounded, but that's crazy. */ | |
d98e5504 | 16 | #define CACHE_MAX 4096 |
cbd4560e | 17 | |
d98e5504 LP |
18 | /* We never keep any item longer than 2h in our cache */ |
19 | #define CACHE_TTL_MAX_USEC (2 * USEC_PER_HOUR) | |
322345fd | 20 | |
201d9958 LP |
21 | /* How long to cache strange rcodes, i.e. rcodes != SUCCESS and != NXDOMAIN (specifically: that's only SERVFAIL for |
22 | * now) */ | |
19bcef9d | 23 | #define CACHE_TTL_STRANGE_RCODE_USEC (10 * USEC_PER_SEC) |
201d9958 | 24 | |
43fc4baa | 25 | #define CACHEABLE_QUERY_FLAGS (SD_RESOLVED_AUTHENTICATED|SD_RESOLVED_CONFIDENTIAL) |
6f055e43 | 26 | |
623a4c97 LP |
27 | typedef enum DnsCacheItemType DnsCacheItemType; |
28 | typedef struct DnsCacheItem DnsCacheItem; | |
29 | ||
30 | enum DnsCacheItemType { | |
31 | DNS_CACHE_POSITIVE, | |
32 | DNS_CACHE_NODATA, | |
33 | DNS_CACHE_NXDOMAIN, | |
201d9958 | 34 | DNS_CACHE_RCODE, /* "strange" RCODE (effective only SERVFAIL for now) */ |
623a4c97 LP |
35 | }; |
36 | ||
37 | struct DnsCacheItem { | |
d2579eec | 38 | DnsCacheItemType type; |
8e95506a | 39 | int rcode; |
775ae354 LP |
40 | DnsResourceKey *key; /* The key for this item, i.e. the lookup key */ |
41 | DnsResourceRecord *rr; /* The RR for this item, i.e. the lookup value for positive queries */ | |
42 | DnsAnswer *answer; /* The full validated answer, if this is an RRset acquired via a "primary" lookup */ | |
43 | DnsPacket *full_packet; /* The full packet this information was acquired with */ | |
d2579eec | 44 | |
623a4c97 | 45 | usec_t until; |
43fc4baa | 46 | uint64_t query_flags; /* SD_RESOLVED_AUTHENTICATED and/or SD_RESOLVED_CONFIDENTIAL */ |
775ae354 | 47 | DnssecResult dnssec_result; |
d2579eec | 48 | |
06d12754 | 49 | int ifindex; |
a4076574 LP |
50 | int owner_family; |
51 | union in_addr_union owner_address; | |
d2579eec LP |
52 | |
53 | unsigned prioq_idx; | |
623a4c97 | 54 | LIST_FIELDS(DnsCacheItem, by_key); |
8e95506a YW |
55 | |
56 | bool shared_owner; | |
623a4c97 LP |
57 | }; |
58 | ||
775ae354 LP |
59 | /* Returns true if this is a cache item created as result of an explicit lookup, or created as "side-effect" |
60 | * of another request. "Primary" entries will carry the full answer data (with NSEC, …) that can aso prove | |
61 | * wildcard expansion, non-existance and such, while entries that were created as "side-effect" just contain | |
62 | * immediate RR data for the specified RR key, but nothing else. */ | |
63 | #define DNS_CACHE_ITEM_IS_PRIMARY(item) (!!(item)->answer) | |
64 | ||
201d9958 LP |
65 | static const char *dns_cache_item_type_to_string(DnsCacheItem *item) { |
66 | assert(item); | |
67 | ||
68 | switch (item->type) { | |
69 | ||
70 | case DNS_CACHE_POSITIVE: | |
71 | return "POSITIVE"; | |
72 | ||
73 | case DNS_CACHE_NODATA: | |
74 | return "NODATA"; | |
75 | ||
76 | case DNS_CACHE_NXDOMAIN: | |
77 | return "NXDOMAIN"; | |
78 | ||
79 | case DNS_CACHE_RCODE: | |
80 | return dns_rcode_to_string(item->rcode); | |
81 | } | |
82 | ||
83 | return NULL; | |
84 | } | |
85 | ||
75db809a | 86 | static DnsCacheItem* dns_cache_item_free(DnsCacheItem *i) { |
322345fd | 87 | if (!i) |
75db809a | 88 | return NULL; |
322345fd LP |
89 | |
90 | dns_resource_record_unref(i->rr); | |
7e8e0422 | 91 | dns_resource_key_unref(i->key); |
775ae354 LP |
92 | dns_answer_unref(i->answer); |
93 | dns_packet_unref(i->full_packet); | |
75db809a | 94 | return mfree(i); |
322345fd | 95 | } |
322345fd LP |
96 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsCacheItem*, dns_cache_item_free); |
97 | ||
39963f11 | 98 | static void dns_cache_item_unlink_and_free(DnsCache *c, DnsCacheItem *i) { |
322345fd LP |
99 | DnsCacheItem *first; |
100 | ||
101 | assert(c); | |
102 | ||
103 | if (!i) | |
104 | return; | |
105 | ||
7e8e0422 LP |
106 | first = hashmap_get(c->by_key, i->key); |
107 | LIST_REMOVE(by_key, first, i); | |
322345fd LP |
108 | |
109 | if (first) | |
7e8e0422 | 110 | assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); |
322345fd | 111 | else |
7e8e0422 | 112 | hashmap_remove(c->by_key, i->key); |
322345fd | 113 | |
7e8e0422 | 114 | prioq_remove(c->by_expiry, i, &i->prioq_idx); |
322345fd LP |
115 | |
116 | dns_cache_item_free(i); | |
117 | } | |
118 | ||
f5bdeb01 | 119 | static bool dns_cache_remove_by_rr(DnsCache *c, DnsResourceRecord *rr) { |
03677889 | 120 | DnsCacheItem *first; |
f5bdeb01 LP |
121 | int r; |
122 | ||
123 | first = hashmap_get(c->by_key, rr->key); | |
124 | LIST_FOREACH(by_key, i, first) { | |
125 | r = dns_resource_record_equal(i->rr, rr); | |
126 | if (r < 0) | |
127 | return r; | |
128 | if (r > 0) { | |
39963f11 | 129 | dns_cache_item_unlink_and_free(c, i); |
f5bdeb01 LP |
130 | return true; |
131 | } | |
132 | } | |
133 | ||
134 | return false; | |
135 | } | |
136 | ||
2dda578f | 137 | static bool dns_cache_remove_by_key(DnsCache *c, DnsResourceKey *key) { |
03677889 | 138 | DnsCacheItem *first; |
322345fd LP |
139 | |
140 | assert(c); | |
141 | assert(key); | |
142 | ||
1f97052f LP |
143 | first = hashmap_remove(c->by_key, key); |
144 | if (!first) | |
145 | return false; | |
146 | ||
80a226b2 | 147 | LIST_FOREACH(by_key, i, first) { |
1f97052f LP |
148 | prioq_remove(c->by_expiry, i, &i->prioq_idx); |
149 | dns_cache_item_free(i); | |
6b34a6c9 TG |
150 | } |
151 | ||
1f97052f | 152 | return true; |
322345fd LP |
153 | } |
154 | ||
ef9a3e3c LP |
155 | void dns_cache_flush(DnsCache *c) { |
156 | DnsResourceKey *key; | |
157 | ||
158 | assert(c); | |
159 | ||
160 | while ((key = hashmap_first_key(c->by_key))) | |
2dda578f | 161 | dns_cache_remove_by_key(c, key); |
ef9a3e3c LP |
162 | |
163 | assert(hashmap_size(c->by_key) == 0); | |
164 | assert(prioq_size(c->by_expiry) == 0); | |
165 | ||
166 | c->by_key = hashmap_free(c->by_key); | |
167 | c->by_expiry = prioq_free(c->by_expiry); | |
168 | } | |
169 | ||
322345fd LP |
170 | static void dns_cache_make_space(DnsCache *c, unsigned add) { |
171 | assert(c); | |
172 | ||
173 | if (add <= 0) | |
174 | return; | |
175 | ||
176 | /* Makes space for n new entries. Note that we actually allow | |
177 | * the cache to grow beyond CACHE_MAX, but only when we shall | |
178 | * add more RRs to the cache than CACHE_MAX at once. In that | |
179 | * case the cache will be emptied completely otherwise. */ | |
180 | ||
181 | for (;;) { | |
faa133f3 | 182 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; |
322345fd LP |
183 | DnsCacheItem *i; |
184 | ||
7e8e0422 | 185 | if (prioq_size(c->by_expiry) <= 0) |
322345fd LP |
186 | break; |
187 | ||
7e8e0422 | 188 | if (prioq_size(c->by_expiry) + add < CACHE_MAX) |
322345fd LP |
189 | break; |
190 | ||
7e8e0422 | 191 | i = prioq_peek(c->by_expiry); |
cbd4560e LP |
192 | assert(i); |
193 | ||
faa133f3 | 194 | /* Take an extra reference to the key so that it |
cbd4560e | 195 | * doesn't go away in the middle of the remove call */ |
7e8e0422 | 196 | key = dns_resource_key_ref(i->key); |
2dda578f | 197 | dns_cache_remove_by_key(c, key); |
322345fd LP |
198 | } |
199 | } | |
200 | ||
201 | void dns_cache_prune(DnsCache *c) { | |
202 | usec_t t = 0; | |
203 | ||
204 | assert(c); | |
205 | ||
206 | /* Remove all entries that are past their TTL */ | |
207 | ||
208 | for (;;) { | |
209 | DnsCacheItem *i; | |
202b76ae | 210 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
322345fd | 211 | |
7e8e0422 | 212 | i = prioq_peek(c->by_expiry); |
322345fd LP |
213 | if (!i) |
214 | break; | |
215 | ||
322345fd | 216 | if (t <= 0) |
ba4e0427 | 217 | t = now(CLOCK_BOOTTIME); |
322345fd | 218 | |
7e8e0422 | 219 | if (i->until > t) |
322345fd LP |
220 | break; |
221 | ||
d2579eec | 222 | /* Depending whether this is an mDNS shared entry |
202b76ae ZJS |
223 | * either remove only this one RR or the whole RRset */ |
224 | log_debug("Removing %scache entry for %s (expired "USEC_FMT"s ago)", | |
225 | i->shared_owner ? "shared " : "", | |
226 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), | |
227 | (t - i->until) / USEC_PER_SEC); | |
228 | ||
d2579eec | 229 | if (i->shared_owner) |
39963f11 | 230 | dns_cache_item_unlink_and_free(c, i); |
d2579eec LP |
231 | else { |
232 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; | |
233 | ||
234 | /* Take an extra reference to the key so that it | |
235 | * doesn't go away in the middle of the remove call */ | |
236 | key = dns_resource_key_ref(i->key); | |
2dda578f | 237 | dns_cache_remove_by_key(c, key); |
d2579eec | 238 | } |
322345fd LP |
239 | } |
240 | } | |
241 | ||
242 | static int dns_cache_item_prioq_compare_func(const void *a, const void *b) { | |
322345fd LP |
243 | const DnsCacheItem *x = a, *y = b; |
244 | ||
a0edd02e | 245 | return CMP(x->until, y->until); |
322345fd LP |
246 | } |
247 | ||
623a4c97 | 248 | static int dns_cache_init(DnsCache *c) { |
7e8e0422 LP |
249 | int r; |
250 | ||
623a4c97 LP |
251 | assert(c); |
252 | ||
7e8e0422 LP |
253 | r = prioq_ensure_allocated(&c->by_expiry, dns_cache_item_prioq_compare_func); |
254 | if (r < 0) | |
255 | return r; | |
256 | ||
d5099efc | 257 | r = hashmap_ensure_allocated(&c->by_key, &dns_resource_key_hash_ops); |
7e8e0422 LP |
258 | if (r < 0) |
259 | return r; | |
260 | ||
261 | return r; | |
262 | } | |
263 | ||
264 | static int dns_cache_link_item(DnsCache *c, DnsCacheItem *i) { | |
265 | DnsCacheItem *first; | |
266 | int r; | |
267 | ||
322345fd LP |
268 | assert(c); |
269 | assert(i); | |
322345fd | 270 | |
7e8e0422 LP |
271 | r = prioq_put(c->by_expiry, i, &i->prioq_idx); |
272 | if (r < 0) | |
273 | return r; | |
322345fd | 274 | |
7e8e0422 LP |
275 | first = hashmap_get(c->by_key, i->key); |
276 | if (first) { | |
d7ac0952 | 277 | _unused_ _cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL; |
f57e3cd5 LP |
278 | |
279 | /* Keep a reference to the original key, while we manipulate the list. */ | |
280 | k = dns_resource_key_ref(first->key); | |
281 | ||
282 | /* Now, try to reduce the number of keys we keep */ | |
283 | dns_resource_key_reduce(&first->key, &i->key); | |
284 | ||
285 | if (first->rr) | |
286 | dns_resource_key_reduce(&first->rr->key, &i->key); | |
287 | if (i->rr) | |
288 | dns_resource_key_reduce(&i->rr->key, &i->key); | |
289 | ||
7e8e0422 LP |
290 | LIST_PREPEND(by_key, first, i); |
291 | assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); | |
292 | } else { | |
293 | r = hashmap_put(c->by_key, i->key, i); | |
294 | if (r < 0) { | |
295 | prioq_remove(c->by_expiry, i, &i->prioq_idx); | |
296 | return r; | |
297 | } | |
322345fd LP |
298 | } |
299 | ||
7e8e0422 | 300 | return 0; |
322345fd LP |
301 | } |
302 | ||
faa133f3 | 303 | static DnsCacheItem* dns_cache_get(DnsCache *c, DnsResourceRecord *rr) { |
faa133f3 LP |
304 | assert(c); |
305 | assert(rr); | |
306 | ||
03677889 | 307 | LIST_FOREACH(by_key, i, (DnsCacheItem*) hashmap_get(c->by_key, rr->key)) |
3ef77d04 | 308 | if (i->rr && dns_resource_record_equal(i->rr, rr) > 0) |
faa133f3 LP |
309 | return i; |
310 | ||
311 | return NULL; | |
312 | } | |
313 | ||
b974211a LP |
314 | static usec_t calculate_until( |
315 | DnsResourceRecord *rr, | |
316 | uint32_t min_ttl, | |
317 | uint32_t nsec_ttl, | |
318 | usec_t timestamp, | |
319 | bool use_soa_minimum) { | |
320 | ||
b211dc7e LP |
321 | uint32_t ttl; |
322 | usec_t u; | |
ee3d6aff LP |
323 | |
324 | assert(rr); | |
325 | ||
b974211a | 326 | ttl = MIN(min_ttl, nsec_ttl); |
b211dc7e | 327 | if (rr->key->type == DNS_TYPE_SOA && use_soa_minimum) { |
3b7006cb LP |
328 | /* If this is a SOA RR, and it is requested, clamp to the SOA's minimum field. This is used |
329 | * when we do negative caching, to determine the TTL for the negative caching entry. See RFC | |
330 | * 2308, Section 5. */ | |
ee3d6aff | 331 | |
b211dc7e LP |
332 | if (ttl > rr->soa.minimum) |
333 | ttl = rr->soa.minimum; | |
334 | } | |
335 | ||
336 | u = ttl * USEC_PER_SEC; | |
337 | if (u > CACHE_TTL_MAX_USEC) | |
338 | u = CACHE_TTL_MAX_USEC; | |
ee3d6aff LP |
339 | |
340 | if (rr->expiry != USEC_INFINITY) { | |
341 | usec_t left; | |
342 | ||
3b7006cb | 343 | /* Make use of the DNSSEC RRSIG expiry info, if we have it */ |
ee3d6aff LP |
344 | |
345 | left = LESS_BY(rr->expiry, now(CLOCK_REALTIME)); | |
b211dc7e LP |
346 | if (u > left) |
347 | u = left; | |
ee3d6aff LP |
348 | } |
349 | ||
b211dc7e | 350 | return timestamp + u; |
ee3d6aff LP |
351 | } |
352 | ||
d2579eec LP |
353 | static void dns_cache_item_update_positive( |
354 | DnsCache *c, | |
355 | DnsCacheItem *i, | |
356 | DnsResourceRecord *rr, | |
775ae354 LP |
357 | DnsAnswer *answer, |
358 | DnsPacket *full_packet, | |
b974211a | 359 | uint32_t min_ttl, |
6f055e43 | 360 | uint64_t query_flags, |
d2579eec | 361 | bool shared_owner, |
775ae354 | 362 | DnssecResult dnssec_result, |
d2579eec | 363 | usec_t timestamp, |
06d12754 | 364 | int ifindex, |
d2579eec LP |
365 | int owner_family, |
366 | const union in_addr_union *owner_address) { | |
367 | ||
7e8e0422 LP |
368 | assert(c); |
369 | assert(i); | |
370 | assert(rr); | |
d2579eec | 371 | assert(owner_address); |
7e8e0422 LP |
372 | |
373 | i->type = DNS_CACHE_POSITIVE; | |
374 | ||
ece174c5 | 375 | if (!i->by_key_prev) |
7e8e0422 LP |
376 | /* We are the first item in the list, we need to |
377 | * update the key used in the hashmap */ | |
378 | ||
379 | assert_se(hashmap_replace(c->by_key, rr->key, i) >= 0); | |
7e8e0422 | 380 | |
7daeec3e | 381 | DNS_RR_REPLACE(i->rr, dns_resource_record_ref(rr)); |
7e8e0422 | 382 | |
57318441 | 383 | DNS_RESOURCE_KEY_REPLACE(i->key, dns_resource_key_ref(rr->key)); |
7e8e0422 | 384 | |
1117a960 | 385 | DNS_ANSWER_REPLACE(i->answer, dns_answer_ref(answer)); |
775ae354 LP |
386 | |
387 | dns_packet_ref(full_packet); | |
388 | dns_packet_unref(i->full_packet); | |
389 | i->full_packet = full_packet; | |
390 | ||
b974211a | 391 | i->until = calculate_until(rr, min_ttl, UINT32_MAX, timestamp, false); |
6f055e43 | 392 | i->query_flags = query_flags & CACHEABLE_QUERY_FLAGS; |
d2579eec | 393 | i->shared_owner = shared_owner; |
775ae354 | 394 | i->dnssec_result = dnssec_result; |
d2579eec | 395 | |
06d12754 LP |
396 | i->ifindex = ifindex; |
397 | ||
d2579eec LP |
398 | i->owner_family = owner_family; |
399 | i->owner_address = *owner_address; | |
7e8e0422 LP |
400 | |
401 | prioq_reshuffle(c->by_expiry, i, &i->prioq_idx); | |
402 | } | |
403 | ||
a4076574 LP |
404 | static int dns_cache_put_positive( |
405 | DnsCache *c, | |
406 | DnsResourceRecord *rr, | |
775ae354 LP |
407 | DnsAnswer *answer, |
408 | DnsPacket *full_packet, | |
6f055e43 | 409 | uint64_t query_flags, |
d2579eec | 410 | bool shared_owner, |
775ae354 | 411 | DnssecResult dnssec_result, |
a4076574 | 412 | usec_t timestamp, |
06d12754 | 413 | int ifindex, |
a4076574 LP |
414 | int owner_family, |
415 | const union in_addr_union *owner_address) { | |
416 | ||
322345fd | 417 | _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; |
518a66ec | 418 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
b974211a LP |
419 | DnsCacheItem *existing; |
420 | uint32_t min_ttl; | |
f6d80c36 | 421 | int r; |
322345fd LP |
422 | |
423 | assert(c); | |
424 | assert(rr); | |
a4076574 | 425 | assert(owner_address); |
322345fd | 426 | |
222148b6 LP |
427 | /* Never cache pseudo RRs */ |
428 | if (dns_class_is_pseudo(rr->key->class)) | |
429 | return 0; | |
430 | if (dns_type_is_pseudo(rr->key->type)) | |
431 | return 0; | |
432 | ||
b974211a LP |
433 | /* Determine the minimal TTL of all RRs in the answer plus the one by the main RR we are supposed to |
434 | * cache. Since we cache whole answers to questions we should never return answers where only some | |
435 | * RRs are still valid, hence find the lowest here */ | |
18da9364 | 436 | min_ttl = MIN(dns_answer_min_ttl(answer), rr->ttl); |
b974211a | 437 | |
f5bdeb01 | 438 | /* New TTL is 0? Delete this specific entry... */ |
b974211a | 439 | if (min_ttl <= 0) { |
f6d80c36 | 440 | r = dns_cache_remove_by_rr(c, rr); |
202b76ae | 441 | log_debug("%s: %s", |
f6d80c36 | 442 | r > 0 ? "Removed zero TTL entry from cache" : "Not caching zero TTL cache entry", |
18665d1f | 443 | dns_resource_key_to_string(rr->key, key_str, sizeof key_str)); |
322345fd LP |
444 | return 0; |
445 | } | |
446 | ||
13e785f7 | 447 | /* Entry exists already? Update TTL, timestamp and owner */ |
322345fd LP |
448 | existing = dns_cache_get(c, rr); |
449 | if (existing) { | |
d2579eec LP |
450 | dns_cache_item_update_positive( |
451 | c, | |
452 | existing, | |
453 | rr, | |
775ae354 LP |
454 | answer, |
455 | full_packet, | |
b974211a | 456 | min_ttl, |
6f055e43 | 457 | query_flags, |
d2579eec | 458 | shared_owner, |
775ae354 | 459 | dnssec_result, |
d2579eec | 460 | timestamp, |
06d12754 | 461 | ifindex, |
d2579eec LP |
462 | owner_family, |
463 | owner_address); | |
322345fd LP |
464 | return 0; |
465 | } | |
466 | ||
467 | /* Otherwise, add the new RR */ | |
623a4c97 | 468 | r = dns_cache_init(c); |
322345fd LP |
469 | if (r < 0) |
470 | return r; | |
471 | ||
7e8e0422 LP |
472 | dns_cache_make_space(c, 1); |
473 | ||
1ed31408 | 474 | i = new(DnsCacheItem, 1); |
7e8e0422 LP |
475 | if (!i) |
476 | return -ENOMEM; | |
477 | ||
1ed31408 LP |
478 | *i = (DnsCacheItem) { |
479 | .type = DNS_CACHE_POSITIVE, | |
480 | .key = dns_resource_key_ref(rr->key), | |
481 | .rr = dns_resource_record_ref(rr), | |
775ae354 LP |
482 | .answer = dns_answer_ref(answer), |
483 | .full_packet = dns_packet_ref(full_packet), | |
b974211a | 484 | .until = calculate_until(rr, min_ttl, UINT32_MAX, timestamp, false), |
6f055e43 | 485 | .query_flags = query_flags & CACHEABLE_QUERY_FLAGS, |
1ed31408 | 486 | .shared_owner = shared_owner, |
775ae354 | 487 | .dnssec_result = dnssec_result, |
1ed31408 LP |
488 | .ifindex = ifindex, |
489 | .owner_family = owner_family, | |
490 | .owner_address = *owner_address, | |
491 | .prioq_idx = PRIOQ_IDX_NULL, | |
492 | }; | |
7e8e0422 LP |
493 | |
494 | r = dns_cache_link_item(c, i); | |
495 | if (r < 0) | |
496 | return r; | |
497 | ||
f1d34068 | 498 | if (DEBUG_LOGGING) { |
202b76ae ZJS |
499 | _cleanup_free_ char *t = NULL; |
500 | ||
501 | (void) in_addr_to_string(i->owner_family, &i->owner_address, &t); | |
502 | ||
43fc4baa | 503 | log_debug("Added positive %s %s%s cache entry for %s "USEC_FMT"s on %s/%s/%s", |
6f055e43 | 504 | FLAGS_SET(i->query_flags, SD_RESOLVED_AUTHENTICATED) ? "authenticated" : "unauthenticated", |
43fc4baa | 505 | FLAGS_SET(i->query_flags, SD_RESOLVED_CONFIDENTIAL) ? "confidential" : "non-confidential", |
202b76ae ZJS |
506 | i->shared_owner ? " shared" : "", |
507 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), | |
508 | (i->until - timestamp) / USEC_PER_SEC, | |
01afd0f7 | 509 | i->ifindex == 0 ? "*" : FORMAT_IFNAME(i->ifindex), |
202b76ae ZJS |
510 | af_to_name_short(i->owner_family), |
511 | strna(t)); | |
a257f9d4 | 512 | } |
6b34a6c9 | 513 | |
7e8e0422 LP |
514 | i = NULL; |
515 | return 0; | |
516 | } | |
517 | ||
a4076574 LP |
518 | static int dns_cache_put_negative( |
519 | DnsCache *c, | |
520 | DnsResourceKey *key, | |
521 | int rcode, | |
775ae354 LP |
522 | DnsAnswer *answer, |
523 | DnsPacket *full_packet, | |
6f055e43 | 524 | uint64_t query_flags, |
775ae354 | 525 | DnssecResult dnssec_result, |
d3760be0 | 526 | uint32_t nsec_ttl, |
a4076574 | 527 | usec_t timestamp, |
b211dc7e | 528 | DnsResourceRecord *soa, |
a4076574 LP |
529 | int owner_family, |
530 | const union in_addr_union *owner_address) { | |
531 | ||
7e8e0422 | 532 | _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; |
202b76ae | 533 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
7e8e0422 LP |
534 | int r; |
535 | ||
536 | assert(c); | |
537 | assert(key); | |
a4076574 | 538 | assert(owner_address); |
7e8e0422 | 539 | |
98b6be77 LP |
540 | /* Never cache pseudo RR keys. DNS_TYPE_ANY is particularly |
541 | * important to filter out as we use this as a pseudo-type for | |
542 | * NXDOMAIN entries */ | |
222148b6 | 543 | if (dns_class_is_pseudo(key->class)) |
ddf16339 | 544 | return 0; |
c33be4a6 | 545 | if (dns_type_is_pseudo(key->type)) |
ddf16339 | 546 | return 0; |
222148b6 | 547 | |
201d9958 LP |
548 | if (IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) { |
549 | if (!soa) | |
550 | return 0; | |
ddf16339 | 551 | |
201d9958 LP |
552 | /* For negative replies, check if we have a TTL of a SOA */ |
553 | if (nsec_ttl <= 0 || soa->soa.minimum <= 0 || soa->ttl <= 0) { | |
554 | log_debug("Not caching negative entry with zero SOA/NSEC/NSEC3 TTL: %s", | |
555 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
556 | return 0; | |
557 | } | |
558 | } else if (rcode != DNS_RCODE_SERVFAIL) | |
7e8e0422 LP |
559 | return 0; |
560 | ||
623a4c97 | 561 | r = dns_cache_init(c); |
322345fd LP |
562 | if (r < 0) |
563 | return r; | |
564 | ||
565 | dns_cache_make_space(c, 1); | |
566 | ||
1ed31408 | 567 | i = new(DnsCacheItem, 1); |
322345fd LP |
568 | if (!i) |
569 | return -ENOMEM; | |
570 | ||
1ed31408 LP |
571 | *i = (DnsCacheItem) { |
572 | .type = | |
573 | rcode == DNS_RCODE_SUCCESS ? DNS_CACHE_NODATA : | |
574 | rcode == DNS_RCODE_NXDOMAIN ? DNS_CACHE_NXDOMAIN : DNS_CACHE_RCODE, | |
6f055e43 | 575 | .query_flags = query_flags & CACHEABLE_QUERY_FLAGS, |
775ae354 | 576 | .dnssec_result = dnssec_result, |
1ed31408 LP |
577 | .owner_family = owner_family, |
578 | .owner_address = *owner_address, | |
579 | .prioq_idx = PRIOQ_IDX_NULL, | |
580 | .rcode = rcode, | |
775ae354 LP |
581 | .answer = dns_answer_ref(answer), |
582 | .full_packet = dns_packet_ref(full_packet), | |
1ed31408 | 583 | }; |
322345fd | 584 | |
b974211a LP |
585 | /* Determine how long to cache this entry. In case we have some RRs in the answer use the lowest TTL |
586 | * of any of them. Typically that's the SOA's TTL, which is OK, but could possibly be lower because | |
587 | * of some other RR. Let's better take the lowest option here than a needlessly high one */ | |
eaa26948 LP |
588 | i->until = |
589 | i->type == DNS_CACHE_RCODE ? timestamp + CACHE_TTL_STRANGE_RCODE_USEC : | |
b974211a | 590 | calculate_until(soa, dns_answer_min_ttl(answer), nsec_ttl, timestamp, true); |
eaa26948 | 591 | |
71e13669 TG |
592 | if (i->type == DNS_CACHE_NXDOMAIN) { |
593 | /* NXDOMAIN entries should apply equally to all types, so we use ANY as | |
594 | * a pseudo type for this purpose here. */ | |
1c02e7ba | 595 | i->key = dns_resource_key_new(key->class, DNS_TYPE_ANY, dns_resource_key_name(key)); |
71e13669 TG |
596 | if (!i->key) |
597 | return -ENOMEM; | |
a5444ca9 LP |
598 | |
599 | /* Make sure to remove any previous entry for this | |
600 | * specific ANY key. (For non-ANY keys the cache data | |
601 | * is already cleared by the caller.) Note that we | |
602 | * don't bother removing positive or NODATA cache | |
603 | * items in this case, because it would either be slow | |
604 | * or require explicit indexing by name */ | |
605 | dns_cache_remove_by_key(c, key); | |
71e13669 TG |
606 | } else |
607 | i->key = dns_resource_key_ref(key); | |
608 | ||
7e8e0422 | 609 | r = dns_cache_link_item(c, i); |
322345fd LP |
610 | if (r < 0) |
611 | return r; | |
612 | ||
202b76ae | 613 | log_debug("Added %s cache entry for %s "USEC_FMT"s", |
201d9958 | 614 | dns_cache_item_type_to_string(i), |
202b76ae ZJS |
615 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), |
616 | (i->until - timestamp) / USEC_PER_SEC); | |
6b34a6c9 | 617 | |
322345fd | 618 | i = NULL; |
322345fd LP |
619 | return 0; |
620 | } | |
621 | ||
d2579eec LP |
622 | static void dns_cache_remove_previous( |
623 | DnsCache *c, | |
624 | DnsResourceKey *key, | |
625 | DnsAnswer *answer) { | |
626 | ||
627 | DnsResourceRecord *rr; | |
628 | DnsAnswerFlags flags; | |
629 | ||
630 | assert(c); | |
631 | ||
632 | /* First, if we were passed a key (i.e. on LLMNR/DNS, but | |
633 | * not on mDNS), delete all matching old RRs, so that we only | |
634 | * keep complete by_key in place. */ | |
635 | if (key) | |
2dda578f | 636 | dns_cache_remove_by_key(c, key); |
d2579eec LP |
637 | |
638 | /* Second, flush all entries matching the answer, unless this | |
639 | * is an RR that is explicitly marked to be "shared" between | |
640 | * peers (i.e. mDNS RRs without the flush-cache bit set). */ | |
641 | DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { | |
642 | if ((flags & DNS_ANSWER_CACHEABLE) == 0) | |
643 | continue; | |
644 | ||
645 | if (flags & DNS_ANSWER_SHARED_OWNER) | |
646 | continue; | |
647 | ||
2dda578f | 648 | dns_cache_remove_by_key(c, rr->key); |
d2579eec LP |
649 | } |
650 | } | |
651 | ||
f6618dcd LP |
652 | static bool rr_eligible(DnsResourceRecord *rr) { |
653 | assert(rr); | |
654 | ||
655 | /* When we see an NSEC/NSEC3 RR, we'll only cache it if it is from the lower zone, not the upper zone, since | |
656 | * that's where the interesting bits are (with exception of DS RRs). Of course, this way we cannot derive DS | |
657 | * existence from any cached NSEC/NSEC3, but that should be fine. */ | |
658 | ||
659 | switch (rr->key->type) { | |
660 | ||
661 | case DNS_TYPE_NSEC: | |
662 | return !bitmap_isset(rr->nsec.types, DNS_TYPE_NS) || | |
663 | bitmap_isset(rr->nsec.types, DNS_TYPE_SOA); | |
664 | ||
665 | case DNS_TYPE_NSEC3: | |
666 | return !bitmap_isset(rr->nsec3.types, DNS_TYPE_NS) || | |
667 | bitmap_isset(rr->nsec3.types, DNS_TYPE_SOA); | |
668 | ||
669 | default: | |
670 | return true; | |
671 | } | |
672 | } | |
673 | ||
a4076574 LP |
674 | int dns_cache_put( |
675 | DnsCache *c, | |
37d7a7d9 | 676 | DnsCacheMode cache_mode, |
8e427d9b | 677 | DnsResourceKey *key, |
a4076574 LP |
678 | int rcode, |
679 | DnsAnswer *answer, | |
775ae354 | 680 | DnsPacket *full_packet, |
6f055e43 | 681 | uint64_t query_flags, |
775ae354 | 682 | DnssecResult dnssec_result, |
d3760be0 | 683 | uint32_t nsec_ttl, |
a4076574 LP |
684 | int owner_family, |
685 | const union in_addr_union *owner_address) { | |
686 | ||
9c5fcb8a | 687 | DnsResourceRecord *soa = NULL; |
201d9958 | 688 | bool weird_rcode = false; |
9c5fcb8a | 689 | DnsAnswerItem *item; |
105e1512 LP |
690 | DnsAnswerFlags flags; |
691 | unsigned cache_keys; | |
43475909 | 692 | usec_t timestamp; |
9c5fcb8a | 693 | int r; |
322345fd LP |
694 | |
695 | assert(c); | |
d2579eec | 696 | assert(owner_address); |
322345fd | 697 | |
d2579eec | 698 | dns_cache_remove_previous(c, key, answer); |
0ec7c46e | 699 | |
201d9958 LP |
700 | /* We only care for positive replies and NXDOMAINs, on all other replies we will simply flush the respective |
701 | * entries, and that's it. (Well, with one further exception: since some DNS zones (akamai!) return SERVFAIL | |
702 | * consistently for some lookups, and forwarders tend to propagate that we'll cache that too, but only for a | |
703 | * short time.) */ | |
6ff01a0d | 704 | |
201d9958 | 705 | if (IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) { |
77db3cae | 706 | if (dns_answer_isempty(answer)) { |
e55fc5b0 YW |
707 | if (key) { |
708 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; | |
201d9958 | 709 | |
e55fc5b0 YW |
710 | log_debug("Not caching negative entry without a SOA record: %s", |
711 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
712 | } | |
775ae354 | 713 | |
201d9958 LP |
714 | return 0; |
715 | } | |
716 | ||
717 | } else { | |
718 | /* Only cache SERVFAIL as "weird" rcode for now. We can add more later, should that turn out to be | |
719 | * beneficial. */ | |
720 | if (rcode != DNS_RCODE_SERVFAIL) | |
721 | return 0; | |
722 | ||
723 | weird_rcode = true; | |
c3cb6dc2 | 724 | } |
0ec7c46e | 725 | |
ea207b63 | 726 | cache_keys = dns_answer_size(answer); |
8e427d9b | 727 | if (key) |
313cefa1 | 728 | cache_keys++; |
eff91ee0 | 729 | |
7e8e0422 | 730 | /* Make some space for our new entries */ |
eff91ee0 | 731 | dns_cache_make_space(c, cache_keys); |
322345fd | 732 | |
ba4e0427 | 733 | timestamp = now(CLOCK_BOOTTIME); |
322345fd | 734 | |
7e8e0422 | 735 | /* Second, add in positive entries for all contained RRs */ |
9c5fcb8a | 736 | DNS_ANSWER_FOREACH_ITEM(item, answer) { |
775ae354 LP |
737 | int primary = false; |
738 | ||
739 | if (!FLAGS_SET(item->flags, DNS_ANSWER_CACHEABLE) || | |
9c5fcb8a | 740 | !rr_eligible(item->rr)) |
f6618dcd LP |
741 | continue; |
742 | ||
775ae354 LP |
743 | if (key) { |
744 | /* We store the auxiliary RRs and packet data in the cache only if they were in | |
745 | * direct response to the original query. If we cache an RR we also received, and | |
746 | * that is just auxiliary information we can't use the data, hence don't. */ | |
747 | ||
748 | primary = dns_resource_key_match_rr(key, item->rr, NULL); | |
749 | if (primary < 0) | |
750 | return primary; | |
751 | if (primary == 0) { | |
752 | primary = dns_resource_key_match_cname_or_dname(key, item->rr->key, NULL); | |
753 | if (primary < 0) | |
754 | return primary; | |
755 | } | |
756 | } | |
757 | ||
758 | if (!primary) { | |
759 | DnsCacheItem *first; | |
760 | ||
761 | /* Do not replace existing cache items for primary lookups with non-primary | |
762 | * data. After all the primary lookup data is a lot more useful. */ | |
763 | first = hashmap_get(c->by_key, item->rr->key); | |
764 | if (first && DNS_CACHE_ITEM_IS_PRIMARY(first)) | |
765 | return 0; | |
766 | } | |
767 | ||
d2579eec LP |
768 | r = dns_cache_put_positive( |
769 | c, | |
9c5fcb8a | 770 | item->rr, |
775ae354 LP |
771 | primary ? answer : NULL, |
772 | primary ? full_packet : NULL, | |
43fc4baa LP |
773 | ((item->flags & DNS_ANSWER_AUTHENTICATED) ? SD_RESOLVED_AUTHENTICATED : 0) | |
774 | (query_flags & SD_RESOLVED_CONFIDENTIAL), | |
9c5fcb8a | 775 | item->flags & DNS_ANSWER_SHARED_OWNER, |
775ae354 | 776 | dnssec_result, |
d2579eec | 777 | timestamp, |
9c5fcb8a | 778 | item->ifindex, |
775ae354 LP |
779 | owner_family, |
780 | owner_address); | |
7e8e0422 LP |
781 | if (r < 0) |
782 | goto fail; | |
783 | } | |
784 | ||
d2579eec | 785 | if (!key) /* mDNS doesn't know negative caching, really */ |
eff91ee0 DM |
786 | return 0; |
787 | ||
8e427d9b | 788 | /* Third, add in negative entries if the key has no RR */ |
105e1512 | 789 | r = dns_answer_match_key(answer, key, NULL); |
8e427d9b TG |
790 | if (r < 0) |
791 | goto fail; | |
792 | if (r > 0) | |
793 | return 0; | |
7e8e0422 | 794 | |
3b7006cb LP |
795 | /* But not if it has a matching CNAME/DNAME (the negative caching will be done on the canonical name, |
796 | * not on the alias) */ | |
105e1512 | 797 | r = dns_answer_find_cname_or_dname(answer, key, NULL, NULL); |
5d27351f TG |
798 | if (r < 0) |
799 | goto fail; | |
800 | if (r > 0) | |
801 | return 0; | |
802 | ||
201d9958 LP |
803 | /* See https://tools.ietf.org/html/rfc2308, which say that a matching SOA record in the packet is used to |
804 | * enable negative caching. We apply one exception though: if we are about to cache a weird rcode we do so | |
805 | * regardless of a SOA. */ | |
fd009cd8 | 806 | r = dns_answer_find_soa(answer, key, &soa, &flags); |
8e427d9b TG |
807 | if (r < 0) |
808 | goto fail; | |
201d9958 | 809 | if (r == 0 && !weird_rcode) |
fd009cd8 | 810 | return 0; |
201d9958 | 811 | if (r > 0) { |
3b7006cb | 812 | /* Refuse using the SOA data if it is unsigned, but the key is signed */ |
6f055e43 LP |
813 | if (FLAGS_SET(query_flags, SD_RESOLVED_AUTHENTICATED) && |
814 | (flags & DNS_ANSWER_AUTHENTICATED) == 0) | |
201d9958 LP |
815 | return 0; |
816 | } | |
fd009cd8 | 817 | |
37d7a7d9 JN |
818 | if (cache_mode == DNS_CACHE_MODE_NO_NEGATIVE) { |
819 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; | |
820 | log_debug("Not caching negative entry for: %s, cache mode set to no-negative", | |
b12058e8 | 821 | dns_resource_key_to_string(key, key_str, sizeof key_str)); |
37d7a7d9 JN |
822 | return 0; |
823 | } | |
824 | ||
d2579eec LP |
825 | r = dns_cache_put_negative( |
826 | c, | |
827 | key, | |
828 | rcode, | |
775ae354 LP |
829 | answer, |
830 | full_packet, | |
6f055e43 | 831 | query_flags, |
775ae354 | 832 | dnssec_result, |
d3760be0 | 833 | nsec_ttl, |
d2579eec | 834 | timestamp, |
b211dc7e | 835 | soa, |
d2579eec | 836 | owner_family, owner_address); |
8e427d9b TG |
837 | if (r < 0) |
838 | goto fail; | |
322345fd LP |
839 | |
840 | return 0; | |
841 | ||
842 | fail: | |
843 | /* Adding all RRs failed. Let's clean up what we already | |
844 | * added, just in case */ | |
845 | ||
8e427d9b | 846 | if (key) |
2dda578f | 847 | dns_cache_remove_by_key(c, key); |
eff91ee0 | 848 | |
9c5fcb8a LP |
849 | DNS_ANSWER_FOREACH_ITEM(item, answer) { |
850 | if ((item->flags & DNS_ANSWER_CACHEABLE) == 0) | |
105e1512 LP |
851 | continue; |
852 | ||
9c5fcb8a | 853 | dns_cache_remove_by_key(c, item->rr->key); |
105e1512 | 854 | } |
322345fd LP |
855 | |
856 | return r; | |
857 | } | |
858 | ||
37da8931 | 859 | static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, DnsResourceKey *k) { |
58db254a LP |
860 | DnsCacheItem *i; |
861 | const char *n; | |
862 | int r; | |
5643c00a TG |
863 | |
864 | assert(c); | |
865 | assert(k); | |
866 | ||
58db254a LP |
867 | /* If we hit some OOM error, or suchlike, we don't care too |
868 | * much, after all this is just a cache */ | |
869 | ||
5643c00a | 870 | i = hashmap_get(c->by_key, k); |
d7ce6c94 | 871 | if (i) |
37da8931 LP |
872 | return i; |
873 | ||
1c02e7ba | 874 | n = dns_resource_key_name(k); |
37da8931 | 875 | |
71e13669 TG |
876 | /* Check if we have an NXDOMAIN cache item for the name, notice that we use |
877 | * the pseudo-type ANY for NXDOMAIN cache items. */ | |
878 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_ANY, n)); | |
879 | if (i && i->type == DNS_CACHE_NXDOMAIN) | |
880 | return i; | |
881 | ||
d3c7e913 | 882 | if (dns_type_may_redirect(k->type)) { |
d7ce6c94 TG |
883 | /* Check if we have a CNAME record instead */ |
884 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_CNAME, n)); | |
3740146a | 885 | if (i && i->type != DNS_CACHE_NODATA) |
d7ce6c94 | 886 | return i; |
5643c00a | 887 | |
d7ce6c94 TG |
888 | /* OK, let's look for cached DNAME records. */ |
889 | for (;;) { | |
d7ce6c94 TG |
890 | if (isempty(n)) |
891 | return NULL; | |
892 | ||
893 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_DNAME, n)); | |
3740146a | 894 | if (i && i->type != DNS_CACHE_NODATA) |
d7ce6c94 | 895 | return i; |
58db254a | 896 | |
d7ce6c94 | 897 | /* Jump one label ahead */ |
950b692b | 898 | r = dns_name_parent(&n); |
d7ce6c94 TG |
899 | if (r <= 0) |
900 | return NULL; | |
901 | } | |
902 | } | |
5643c00a | 903 | |
950b692b | 904 | if (k->type != DNS_TYPE_NSEC) { |
d7ce6c94 TG |
905 | /* Check if we have an NSEC record instead for the name. */ |
906 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_NSEC, n)); | |
58db254a LP |
907 | if (i) |
908 | return i; | |
58db254a LP |
909 | } |
910 | ||
911 | return NULL; | |
5643c00a TG |
912 | } |
913 | ||
775ae354 LP |
914 | static int answer_add_clamp_ttl( |
915 | DnsAnswer **answer, | |
916 | DnsResourceRecord *rr, | |
917 | int ifindex, | |
918 | DnsAnswerFlags answer_flags, | |
919 | DnsResourceRecord *rrsig, | |
920 | uint64_t query_flags, | |
921 | usec_t until, | |
922 | usec_t current) { | |
923 | ||
924 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *patched = NULL, *patched_rrsig = NULL; | |
925 | int r; | |
926 | ||
927 | assert(answer); | |
928 | assert(rr); | |
929 | ||
930 | if (FLAGS_SET(query_flags, SD_RESOLVED_CLAMP_TTL)) { | |
a1acc6e3 LP |
931 | uint32_t left_ttl; |
932 | ||
e7d48709 ZJS |
933 | assert(current > 0); |
934 | ||
a1acc6e3 LP |
935 | /* Let's determine how much time is left for this cache entry. Note that we round down, but |
936 | * clamp this to be 1s at minimum, since we usually want records to remain cached better too | |
937 | * short a time than too long a time, but otoh don't want to return 0 ever, since that has | |
938 | * special semantics in various contexts — in particular in mDNS */ | |
939 | ||
940 | left_ttl = MAX(1U, LESS_BY(until, current) / USEC_PER_SEC); | |
941 | ||
775ae354 LP |
942 | patched = dns_resource_record_ref(rr); |
943 | ||
a1acc6e3 | 944 | r = dns_resource_record_clamp_ttl(&patched, left_ttl); |
775ae354 LP |
945 | if (r < 0) |
946 | return r; | |
947 | ||
948 | rr = patched; | |
949 | ||
950 | if (rrsig) { | |
951 | patched_rrsig = dns_resource_record_ref(rrsig); | |
a1acc6e3 | 952 | r = dns_resource_record_clamp_ttl(&patched_rrsig, left_ttl); |
775ae354 LP |
953 | if (r < 0) |
954 | return r; | |
955 | ||
956 | rrsig = patched_rrsig; | |
957 | } | |
958 | } | |
959 | ||
960 | r = dns_answer_add_extend(answer, rr, ifindex, answer_flags, rrsig); | |
961 | if (r < 0) | |
962 | return r; | |
963 | ||
964 | return 0; | |
965 | } | |
966 | ||
967 | int dns_cache_lookup( | |
968 | DnsCache *c, | |
969 | DnsResourceKey *key, | |
970 | uint64_t query_flags, | |
971 | int *ret_rcode, | |
972 | DnsAnswer **ret_answer, | |
973 | DnsPacket **ret_full_packet, | |
6f055e43 | 974 | uint64_t *ret_query_flags, |
775ae354 LP |
975 | DnssecResult *ret_dnssec_result) { |
976 | ||
977 | _cleanup_(dns_packet_unrefp) DnsPacket *full_packet = NULL; | |
faa133f3 | 978 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; |
202b76ae | 979 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
f52e61da | 980 | unsigned n = 0; |
322345fd | 981 | int r; |
7e8e0422 | 982 | bool nxdomain = false; |
03677889 | 983 | DnsCacheItem *first, *nsec = NULL; |
43fc4baa | 984 | bool have_authenticated = false, have_non_authenticated = false, have_confidential = false, have_non_confidential = false; |
e7d48709 | 985 | usec_t current = 0; |
201d9958 | 986 | int found_rcode = -1; |
775ae354 LP |
987 | DnssecResult dnssec_result = -1; |
988 | int have_dnssec_result = -1; | |
322345fd LP |
989 | |
990 | assert(c); | |
f52e61da | 991 | assert(key); |
322345fd | 992 | |
202b76ae | 993 | if (key->type == DNS_TYPE_ANY || key->class == DNS_CLASS_ANY) { |
775ae354 LP |
994 | /* If we have ANY lookups we don't use the cache, so that the caller refreshes via the |
995 | * network. */ | |
322345fd | 996 | |
202b76ae ZJS |
997 | log_debug("Ignoring cache for ANY lookup: %s", |
998 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
775ae354 | 999 | goto miss; |
f52e61da | 1000 | } |
6b34a6c9 | 1001 | |
37da8931 | 1002 | first = dns_cache_get_by_key_follow_cname_dname_nsec(c, key); |
f52e61da LP |
1003 | if (!first) { |
1004 | /* If one question cannot be answered we need to refresh */ | |
ddf16339 | 1005 | |
202b76ae ZJS |
1006 | log_debug("Cache miss for %s", |
1007 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
775ae354 LP |
1008 | goto miss; |
1009 | } | |
6b34a6c9 | 1010 | |
e7d48709 ZJS |
1011 | if (FLAGS_SET(query_flags, SD_RESOLVED_CLAMP_TTL)) { |
1012 | /* 'current' is always passed to answer_add_clamp_ttl(), but is only used conditionally. | |
1013 | * We'll do the same assert there to make sure that it was initialized properly. */ | |
ba4e0427 | 1014 | current = now(CLOCK_BOOTTIME); |
e7d48709 ZJS |
1015 | assert(current > 0); |
1016 | } | |
a150ff5e | 1017 | |
775ae354 LP |
1018 | LIST_FOREACH(by_key, j, first) { |
1019 | /* If the caller doesn't allow us to answer questions from cache data learned from | |
1020 | * "side-effect", skip this entry. */ | |
1021 | if (FLAGS_SET(query_flags, SD_RESOLVED_REQUIRE_PRIMARY) && | |
1022 | !DNS_CACHE_ITEM_IS_PRIMARY(j)) { | |
1023 | log_debug("Primary answer was requested for cache lookup for %s, which we don't have.", | |
1024 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
2d4a4e14 | 1025 | |
775ae354 LP |
1026 | goto miss; |
1027 | } | |
6b34a6c9 | 1028 | |
775ae354 LP |
1029 | if (j->type == DNS_CACHE_NXDOMAIN) |
1030 | nxdomain = true; | |
1031 | else if (j->type == DNS_CACHE_RCODE) | |
1032 | found_rcode = j->rcode; | |
1033 | else if (j->rr) { | |
37da8931 | 1034 | if (j->rr->key->type == DNS_TYPE_NSEC) |
931851e8 LP |
1035 | nsec = j; |
1036 | ||
f52e61da | 1037 | n++; |
775ae354 | 1038 | } |
931851e8 | 1039 | |
6f055e43 | 1040 | if (FLAGS_SET(j->query_flags, SD_RESOLVED_AUTHENTICATED)) |
931851e8 LP |
1041 | have_authenticated = true; |
1042 | else | |
1043 | have_non_authenticated = true; | |
775ae354 | 1044 | |
43fc4baa LP |
1045 | if (FLAGS_SET(j->query_flags, SD_RESOLVED_CONFIDENTIAL)) |
1046 | have_confidential = true; | |
1047 | else | |
1048 | have_non_confidential = true; | |
1049 | ||
775ae354 LP |
1050 | if (j->dnssec_result < 0) { |
1051 | have_dnssec_result = false; /* an entry without dnssec result? then invalidate things for good */ | |
1052 | dnssec_result = _DNSSEC_RESULT_INVALID; | |
1053 | } else if (have_dnssec_result < 0) { | |
1054 | have_dnssec_result = true; /* So far no result seen, let's pick this one up */ | |
1055 | dnssec_result = j->dnssec_result; | |
1056 | } else if (have_dnssec_result > 0 && j->dnssec_result != dnssec_result) { | |
1057 | have_dnssec_result = false; /* conflicting result seen? then invalidate for good */ | |
1058 | dnssec_result = _DNSSEC_RESULT_INVALID; | |
1059 | } | |
1060 | ||
1061 | /* Append the answer RRs to our answer. Ideally we have the answer object, which we | |
1062 | * preferably use. But if the cached entry was generated as "side-effect" of a reply, | |
1063 | * i.e. from validated auxiliary records rather than from the main reply, then we use the | |
1064 | * individual RRs only instead. */ | |
1065 | if (j->answer) { | |
1066 | ||
1067 | /* Minor optimization, if the full answer object of this and the previous RR is the | |
1068 | * same, don't bother adding it again. Typically we store a full RRset here, hence | |
1069 | * that should be the case. */ | |
1070 | if (!j->by_key_prev || j->answer != j->by_key_prev->answer) { | |
1071 | DnsAnswerItem *item; | |
1072 | ||
1073 | DNS_ANSWER_FOREACH_ITEM(item, j->answer) { | |
b974211a LP |
1074 | r = answer_add_clamp_ttl( |
1075 | &answer, | |
1076 | item->rr, | |
1077 | item->ifindex, | |
1078 | item->flags, | |
1079 | item->rrsig, | |
1080 | query_flags, | |
1081 | j->until, | |
1082 | current); | |
775ae354 LP |
1083 | if (r < 0) |
1084 | return r; | |
1085 | } | |
1086 | } | |
1087 | ||
1088 | } else if (j->rr) { | |
b974211a LP |
1089 | r = answer_add_clamp_ttl( |
1090 | &answer, | |
1091 | j->rr, | |
1092 | j->ifindex, | |
1093 | FLAGS_SET(j->query_flags, SD_RESOLVED_AUTHENTICATED) ? DNS_ANSWER_AUTHENTICATED : 0, | |
1094 | NULL, | |
1095 | query_flags, | |
1096 | j->until, | |
1097 | current); | |
775ae354 LP |
1098 | if (r < 0) |
1099 | return r; | |
1100 | } | |
1101 | ||
1102 | /* We'll return any packet we have for this. Typically all cache entries for the same key | |
1103 | * should come from the same packet anyway, hence it doesn't really matter which packet we | |
1104 | * return here, they should all resolve to the same anyway. */ | |
1105 | if (!full_packet && j->full_packet) | |
1106 | full_packet = dns_packet_ref(j->full_packet); | |
f52e61da | 1107 | } |
6b34a6c9 | 1108 | |
201d9958 LP |
1109 | if (found_rcode >= 0) { |
1110 | log_debug("RCODE %s cache hit for %s", | |
1111 | dns_rcode_to_string(found_rcode), | |
1112 | dns_resource_key_to_string(key, key_str, sizeof(key_str))); | |
1113 | ||
775ae354 LP |
1114 | if (ret_rcode) |
1115 | *ret_rcode = found_rcode; | |
1116 | if (ret_answer) | |
1117 | *ret_answer = TAKE_PTR(answer); | |
1118 | if (ret_full_packet) | |
1119 | *ret_full_packet = TAKE_PTR(full_packet); | |
6f055e43 LP |
1120 | if (ret_query_flags) |
1121 | *ret_query_flags = 0; | |
775ae354 LP |
1122 | if (ret_dnssec_result) |
1123 | *ret_dnssec_result = dnssec_result; | |
201d9958 LP |
1124 | |
1125 | c->n_hit++; | |
1126 | return 1; | |
1127 | } | |
1128 | ||
f6618dcd | 1129 | if (nsec && !IN_SET(key->type, DNS_TYPE_NSEC, DNS_TYPE_DS)) { |
775ae354 LP |
1130 | /* Note that we won't derive information for DS RRs from an NSEC, because we only cache NSEC |
1131 | * RRs from the lower-zone of a zone cut, but the DS RRs are on the upper zone. */ | |
f6618dcd | 1132 | |
202b76ae ZJS |
1133 | log_debug("NSEC NODATA cache hit for %s", |
1134 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
37da8931 | 1135 | |
775ae354 LP |
1136 | /* We only found an NSEC record that matches our name. If it says the type doesn't exist |
1137 | * report NODATA. Otherwise report a cache miss. */ | |
37da8931 | 1138 | |
775ae354 LP |
1139 | if (ret_rcode) |
1140 | *ret_rcode = DNS_RCODE_SUCCESS; | |
1141 | if (ret_answer) | |
1142 | *ret_answer = TAKE_PTR(answer); | |
1143 | if (ret_full_packet) | |
1144 | *ret_full_packet = TAKE_PTR(full_packet); | |
6f055e43 LP |
1145 | if (ret_query_flags) |
1146 | *ret_query_flags = nsec->query_flags; | |
775ae354 LP |
1147 | if (ret_dnssec_result) |
1148 | *ret_dnssec_result = nsec->dnssec_result; | |
37da8931 | 1149 | |
a150ff5e LP |
1150 | if (!bitmap_isset(nsec->rr->nsec.types, key->type) && |
1151 | !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_CNAME) && | |
1152 | !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_DNAME)) { | |
1153 | c->n_hit++; | |
1154 | return 1; | |
1155 | } | |
1156 | ||
1157 | c->n_miss++; | |
1158 | return 0; | |
37da8931 LP |
1159 | } |
1160 | ||
202b76ae ZJS |
1161 | log_debug("%s cache hit for %s", |
1162 | n > 0 ? "Positive" : | |
1163 | nxdomain ? "NXDOMAIN" : "NODATA", | |
1164 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
faa133f3 | 1165 | |
7e8e0422 | 1166 | if (n <= 0) { |
a150ff5e LP |
1167 | c->n_hit++; |
1168 | ||
775ae354 LP |
1169 | if (ret_rcode) |
1170 | *ret_rcode = nxdomain ? DNS_RCODE_NXDOMAIN : DNS_RCODE_SUCCESS; | |
1171 | if (ret_answer) | |
1172 | *ret_answer = TAKE_PTR(answer); | |
1173 | if (ret_full_packet) | |
1174 | *ret_full_packet = TAKE_PTR(full_packet); | |
6f055e43 | 1175 | if (ret_query_flags) |
43fc4baa LP |
1176 | *ret_query_flags = |
1177 | ((have_authenticated && !have_non_authenticated) ? SD_RESOLVED_AUTHENTICATED : 0) | | |
1178 | ((have_confidential && !have_non_confidential) ? SD_RESOLVED_CONFIDENTIAL : 0); | |
775ae354 LP |
1179 | if (ret_dnssec_result) |
1180 | *ret_dnssec_result = dnssec_result; | |
17c8de63 | 1181 | |
775ae354 | 1182 | return 1; |
322345fd LP |
1183 | } |
1184 | ||
a150ff5e LP |
1185 | c->n_hit++; |
1186 | ||
775ae354 LP |
1187 | if (ret_rcode) |
1188 | *ret_rcode = DNS_RCODE_SUCCESS; | |
1189 | if (ret_answer) | |
1190 | *ret_answer = TAKE_PTR(answer); | |
1191 | if (ret_full_packet) | |
1192 | *ret_full_packet = TAKE_PTR(full_packet); | |
6f055e43 | 1193 | if (ret_query_flags) |
43fc4baa LP |
1194 | *ret_query_flags = |
1195 | ((have_authenticated && !have_non_authenticated) ? SD_RESOLVED_AUTHENTICATED : 0) | | |
1196 | ((have_confidential && !have_non_confidential) ? SD_RESOLVED_CONFIDENTIAL : 0); | |
775ae354 LP |
1197 | if (ret_dnssec_result) |
1198 | *ret_dnssec_result = dnssec_result; | |
faa133f3 LP |
1199 | |
1200 | return n; | |
775ae354 LP |
1201 | |
1202 | miss: | |
1203 | if (ret_rcode) | |
1204 | *ret_rcode = DNS_RCODE_SUCCESS; | |
1205 | if (ret_answer) | |
1206 | *ret_answer = NULL; | |
1207 | if (ret_full_packet) | |
1208 | *ret_full_packet = NULL; | |
6f055e43 LP |
1209 | if (ret_query_flags) |
1210 | *ret_query_flags = 0; | |
775ae354 LP |
1211 | if (ret_dnssec_result) |
1212 | *ret_dnssec_result = _DNSSEC_RESULT_INVALID; | |
1213 | ||
1214 | c->n_miss++; | |
1215 | return 0; | |
322345fd | 1216 | } |
a4076574 LP |
1217 | |
1218 | int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_family, const union in_addr_union *owner_address) { | |
03677889 | 1219 | DnsCacheItem *first; |
a4076574 LP |
1220 | bool same_owner = true; |
1221 | ||
1222 | assert(cache); | |
1223 | assert(rr); | |
1224 | ||
1225 | dns_cache_prune(cache); | |
1226 | ||
1227 | /* See if there's a cache entry for the same key. If there | |
1228 | * isn't there's no conflict */ | |
1229 | first = hashmap_get(cache->by_key, rr->key); | |
1230 | if (!first) | |
1231 | return 0; | |
1232 | ||
1233 | /* See if the RR key is owned by the same owner, if so, there | |
1234 | * isn't a conflict either */ | |
1235 | LIST_FOREACH(by_key, i, first) { | |
1236 | if (i->owner_family != owner_family || | |
1237 | !in_addr_equal(owner_family, &i->owner_address, owner_address)) { | |
1238 | same_owner = false; | |
1239 | break; | |
1240 | } | |
1241 | } | |
1242 | if (same_owner) | |
1243 | return 0; | |
1244 | ||
1245 | /* See if there's the exact same RR in the cache. If yes, then | |
1246 | * there's no conflict. */ | |
1247 | if (dns_cache_get(cache, rr)) | |
1248 | return 0; | |
1249 | ||
1250 | /* There's a conflict */ | |
1251 | return 1; | |
1252 | } | |
4d506d6b | 1253 | |
7778dfff DM |
1254 | int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p) { |
1255 | unsigned ancount = 0; | |
7778dfff DM |
1256 | DnsCacheItem *i; |
1257 | int r; | |
1258 | ||
1259 | assert(cache); | |
261f3673 | 1260 | assert(p); |
7778dfff | 1261 | |
03677889 | 1262 | HASHMAP_FOREACH(i, cache->by_key) |
7778dfff | 1263 | LIST_FOREACH(by_key, j, i) { |
7778dfff DM |
1264 | if (!j->rr) |
1265 | continue; | |
1266 | ||
d2579eec | 1267 | if (!j->shared_owner) |
7778dfff DM |
1268 | continue; |
1269 | ||
58ab31d5 | 1270 | r = dns_packet_append_rr(p, j->rr, 0, NULL, NULL); |
261f3673 DM |
1271 | if (r == -EMSGSIZE && p->protocol == DNS_PROTOCOL_MDNS) { |
1272 | /* For mDNS, if we're unable to stuff all known answers into the given packet, | |
1273 | * allocate a new one, push the RR into that one and link it to the current one. | |
1274 | */ | |
1275 | ||
1276 | DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); | |
1277 | ancount = 0; | |
1278 | ||
1279 | r = dns_packet_new_query(&p->more, p->protocol, 0, true); | |
1280 | if (r < 0) | |
1281 | return r; | |
1282 | ||
1283 | /* continue with new packet */ | |
1284 | p = p->more; | |
58ab31d5 | 1285 | r = dns_packet_append_rr(p, j->rr, 0, NULL, NULL); |
261f3673 DM |
1286 | } |
1287 | ||
7778dfff DM |
1288 | if (r < 0) |
1289 | return r; | |
1290 | ||
313cefa1 | 1291 | ancount++; |
7778dfff | 1292 | } |
7778dfff DM |
1293 | |
1294 | DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); | |
1295 | ||
1296 | return 0; | |
1297 | } | |
1298 | ||
ca9fab88 | 1299 | void dns_cache_dump(DnsCache *cache, FILE *f) { |
4d506d6b | 1300 | DnsCacheItem *i; |
4d506d6b LP |
1301 | |
1302 | if (!cache) | |
1303 | return; | |
1304 | ||
1305 | if (!f) | |
1306 | f = stdout; | |
1307 | ||
03677889 | 1308 | HASHMAP_FOREACH(i, cache->by_key) |
4d506d6b | 1309 | LIST_FOREACH(by_key, j, i) { |
4d506d6b LP |
1310 | |
1311 | fputc('\t', f); | |
1312 | ||
1313 | if (j->rr) { | |
7b50eb2e LP |
1314 | const char *t; |
1315 | t = dns_resource_record_to_string(j->rr); | |
1316 | if (!t) { | |
4d506d6b LP |
1317 | log_oom(); |
1318 | continue; | |
1319 | } | |
1320 | ||
1321 | fputs(t, f); | |
1322 | fputc('\n', f); | |
1323 | } else { | |
202b76ae | 1324 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
4d506d6b | 1325 | |
202b76ae | 1326 | fputs(dns_resource_key_to_string(j->key, key_str, sizeof key_str), f); |
4d506d6b | 1327 | fputs(" -- ", f); |
201d9958 | 1328 | fputs(dns_cache_item_type_to_string(j), f); |
4d506d6b LP |
1329 | fputc('\n', f); |
1330 | } | |
1331 | } | |
4d506d6b LP |
1332 | } |
1333 | ||
1334 | bool dns_cache_is_empty(DnsCache *cache) { | |
1335 | if (!cache) | |
1336 | return true; | |
1337 | ||
1338 | return hashmap_isempty(cache->by_key); | |
1339 | } | |
a150ff5e LP |
1340 | |
1341 | unsigned dns_cache_size(DnsCache *cache) { | |
1342 | if (!cache) | |
1343 | return 0; | |
1344 | ||
1345 | return hashmap_size(cache->by_key); | |
1346 | } |