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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; |
775ae354 LP |
39 | DnsResourceKey *key; /* The key for this item, i.e. the lookup key */ |
40 | DnsResourceRecord *rr; /* The RR for this item, i.e. the lookup value for positive queries */ | |
41 | DnsAnswer *answer; /* The full validated answer, if this is an RRset acquired via a "primary" lookup */ | |
42 | DnsPacket *full_packet; /* The full packet this information was acquired with */ | |
201d9958 | 43 | int rcode; |
d2579eec | 44 | |
623a4c97 | 45 | usec_t until; |
d2579eec | 46 | bool shared_owner:1; |
43fc4baa | 47 | uint64_t query_flags; /* SD_RESOLVED_AUTHENTICATED and/or SD_RESOLVED_CONFIDENTIAL */ |
775ae354 | 48 | DnssecResult dnssec_result; |
d2579eec | 49 | |
06d12754 | 50 | int ifindex; |
a4076574 LP |
51 | int owner_family; |
52 | union in_addr_union owner_address; | |
d2579eec LP |
53 | |
54 | unsigned prioq_idx; | |
623a4c97 LP |
55 | LIST_FIELDS(DnsCacheItem, by_key); |
56 | }; | |
57 | ||
775ae354 LP |
58 | /* Returns true if this is a cache item created as result of an explicit lookup, or created as "side-effect" |
59 | * of another request. "Primary" entries will carry the full answer data (with NSEC, …) that can aso prove | |
60 | * wildcard expansion, non-existance and such, while entries that were created as "side-effect" just contain | |
61 | * immediate RR data for the specified RR key, but nothing else. */ | |
62 | #define DNS_CACHE_ITEM_IS_PRIMARY(item) (!!(item)->answer) | |
63 | ||
201d9958 LP |
64 | static const char *dns_cache_item_type_to_string(DnsCacheItem *item) { |
65 | assert(item); | |
66 | ||
67 | switch (item->type) { | |
68 | ||
69 | case DNS_CACHE_POSITIVE: | |
70 | return "POSITIVE"; | |
71 | ||
72 | case DNS_CACHE_NODATA: | |
73 | return "NODATA"; | |
74 | ||
75 | case DNS_CACHE_NXDOMAIN: | |
76 | return "NXDOMAIN"; | |
77 | ||
78 | case DNS_CACHE_RCODE: | |
79 | return dns_rcode_to_string(item->rcode); | |
80 | } | |
81 | ||
82 | return NULL; | |
83 | } | |
84 | ||
75db809a | 85 | static DnsCacheItem* dns_cache_item_free(DnsCacheItem *i) { |
322345fd | 86 | if (!i) |
75db809a | 87 | return NULL; |
322345fd LP |
88 | |
89 | dns_resource_record_unref(i->rr); | |
7e8e0422 | 90 | dns_resource_key_unref(i->key); |
775ae354 LP |
91 | dns_answer_unref(i->answer); |
92 | dns_packet_unref(i->full_packet); | |
75db809a | 93 | return mfree(i); |
322345fd | 94 | } |
322345fd LP |
95 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsCacheItem*, dns_cache_item_free); |
96 | ||
39963f11 | 97 | static void dns_cache_item_unlink_and_free(DnsCache *c, DnsCacheItem *i) { |
322345fd LP |
98 | DnsCacheItem *first; |
99 | ||
100 | assert(c); | |
101 | ||
102 | if (!i) | |
103 | return; | |
104 | ||
7e8e0422 LP |
105 | first = hashmap_get(c->by_key, i->key); |
106 | LIST_REMOVE(by_key, first, i); | |
322345fd LP |
107 | |
108 | if (first) | |
7e8e0422 | 109 | assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); |
322345fd | 110 | else |
7e8e0422 | 111 | hashmap_remove(c->by_key, i->key); |
322345fd | 112 | |
7e8e0422 | 113 | prioq_remove(c->by_expiry, i, &i->prioq_idx); |
322345fd LP |
114 | |
115 | dns_cache_item_free(i); | |
116 | } | |
117 | ||
f5bdeb01 LP |
118 | static bool dns_cache_remove_by_rr(DnsCache *c, DnsResourceRecord *rr) { |
119 | DnsCacheItem *first, *i; | |
120 | int r; | |
121 | ||
122 | first = hashmap_get(c->by_key, rr->key); | |
123 | LIST_FOREACH(by_key, i, first) { | |
124 | r = dns_resource_record_equal(i->rr, rr); | |
125 | if (r < 0) | |
126 | return r; | |
127 | if (r > 0) { | |
39963f11 | 128 | dns_cache_item_unlink_and_free(c, i); |
f5bdeb01 LP |
129 | return true; |
130 | } | |
131 | } | |
132 | ||
133 | return false; | |
134 | } | |
135 | ||
2dda578f | 136 | static bool dns_cache_remove_by_key(DnsCache *c, DnsResourceKey *key) { |
1f97052f | 137 | DnsCacheItem *first, *i, *n; |
322345fd LP |
138 | |
139 | assert(c); | |
140 | assert(key); | |
141 | ||
1f97052f LP |
142 | first = hashmap_remove(c->by_key, key); |
143 | if (!first) | |
144 | return false; | |
145 | ||
146 | LIST_FOREACH_SAFE(by_key, i, n, first) { | |
147 | prioq_remove(c->by_expiry, i, &i->prioq_idx); | |
148 | dns_cache_item_free(i); | |
6b34a6c9 TG |
149 | } |
150 | ||
1f97052f | 151 | return true; |
322345fd LP |
152 | } |
153 | ||
ef9a3e3c LP |
154 | void dns_cache_flush(DnsCache *c) { |
155 | DnsResourceKey *key; | |
156 | ||
157 | assert(c); | |
158 | ||
159 | while ((key = hashmap_first_key(c->by_key))) | |
2dda578f | 160 | dns_cache_remove_by_key(c, key); |
ef9a3e3c LP |
161 | |
162 | assert(hashmap_size(c->by_key) == 0); | |
163 | assert(prioq_size(c->by_expiry) == 0); | |
164 | ||
165 | c->by_key = hashmap_free(c->by_key); | |
166 | c->by_expiry = prioq_free(c->by_expiry); | |
167 | } | |
168 | ||
322345fd LP |
169 | static void dns_cache_make_space(DnsCache *c, unsigned add) { |
170 | assert(c); | |
171 | ||
172 | if (add <= 0) | |
173 | return; | |
174 | ||
175 | /* Makes space for n new entries. Note that we actually allow | |
176 | * the cache to grow beyond CACHE_MAX, but only when we shall | |
177 | * add more RRs to the cache than CACHE_MAX at once. In that | |
178 | * case the cache will be emptied completely otherwise. */ | |
179 | ||
180 | for (;;) { | |
faa133f3 | 181 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; |
322345fd LP |
182 | DnsCacheItem *i; |
183 | ||
7e8e0422 | 184 | if (prioq_size(c->by_expiry) <= 0) |
322345fd LP |
185 | break; |
186 | ||
7e8e0422 | 187 | if (prioq_size(c->by_expiry) + add < CACHE_MAX) |
322345fd LP |
188 | break; |
189 | ||
7e8e0422 | 190 | i = prioq_peek(c->by_expiry); |
cbd4560e LP |
191 | assert(i); |
192 | ||
faa133f3 | 193 | /* Take an extra reference to the key so that it |
cbd4560e | 194 | * doesn't go away in the middle of the remove call */ |
7e8e0422 | 195 | key = dns_resource_key_ref(i->key); |
2dda578f | 196 | dns_cache_remove_by_key(c, key); |
322345fd LP |
197 | } |
198 | } | |
199 | ||
200 | void dns_cache_prune(DnsCache *c) { | |
201 | usec_t t = 0; | |
202 | ||
203 | assert(c); | |
204 | ||
205 | /* Remove all entries that are past their TTL */ | |
206 | ||
207 | for (;;) { | |
208 | DnsCacheItem *i; | |
202b76ae | 209 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
322345fd | 210 | |
7e8e0422 | 211 | i = prioq_peek(c->by_expiry); |
322345fd LP |
212 | if (!i) |
213 | break; | |
214 | ||
322345fd | 215 | if (t <= 0) |
240b589b | 216 | t = now(clock_boottime_or_monotonic()); |
322345fd | 217 | |
7e8e0422 | 218 | if (i->until > t) |
322345fd LP |
219 | break; |
220 | ||
d2579eec | 221 | /* Depending whether this is an mDNS shared entry |
202b76ae ZJS |
222 | * either remove only this one RR or the whole RRset */ |
223 | log_debug("Removing %scache entry for %s (expired "USEC_FMT"s ago)", | |
224 | i->shared_owner ? "shared " : "", | |
225 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), | |
226 | (t - i->until) / USEC_PER_SEC); | |
227 | ||
d2579eec | 228 | if (i->shared_owner) |
39963f11 | 229 | dns_cache_item_unlink_and_free(c, i); |
d2579eec LP |
230 | else { |
231 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; | |
232 | ||
233 | /* Take an extra reference to the key so that it | |
234 | * doesn't go away in the middle of the remove call */ | |
235 | key = dns_resource_key_ref(i->key); | |
2dda578f | 236 | dns_cache_remove_by_key(c, key); |
d2579eec | 237 | } |
322345fd LP |
238 | } |
239 | } | |
240 | ||
241 | static int dns_cache_item_prioq_compare_func(const void *a, const void *b) { | |
322345fd LP |
242 | const DnsCacheItem *x = a, *y = b; |
243 | ||
a0edd02e | 244 | return CMP(x->until, y->until); |
322345fd LP |
245 | } |
246 | ||
623a4c97 | 247 | static int dns_cache_init(DnsCache *c) { |
7e8e0422 LP |
248 | int r; |
249 | ||
623a4c97 LP |
250 | assert(c); |
251 | ||
7e8e0422 LP |
252 | r = prioq_ensure_allocated(&c->by_expiry, dns_cache_item_prioq_compare_func); |
253 | if (r < 0) | |
254 | return r; | |
255 | ||
d5099efc | 256 | r = hashmap_ensure_allocated(&c->by_key, &dns_resource_key_hash_ops); |
7e8e0422 LP |
257 | if (r < 0) |
258 | return r; | |
259 | ||
260 | return r; | |
261 | } | |
262 | ||
263 | static int dns_cache_link_item(DnsCache *c, DnsCacheItem *i) { | |
264 | DnsCacheItem *first; | |
265 | int r; | |
266 | ||
322345fd LP |
267 | assert(c); |
268 | assert(i); | |
322345fd | 269 | |
7e8e0422 LP |
270 | r = prioq_put(c->by_expiry, i, &i->prioq_idx); |
271 | if (r < 0) | |
272 | return r; | |
322345fd | 273 | |
7e8e0422 LP |
274 | first = hashmap_get(c->by_key, i->key); |
275 | if (first) { | |
f57e3cd5 LP |
276 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *k = NULL; |
277 | ||
278 | /* Keep a reference to the original key, while we manipulate the list. */ | |
279 | k = dns_resource_key_ref(first->key); | |
280 | ||
281 | /* Now, try to reduce the number of keys we keep */ | |
282 | dns_resource_key_reduce(&first->key, &i->key); | |
283 | ||
284 | if (first->rr) | |
285 | dns_resource_key_reduce(&first->rr->key, &i->key); | |
286 | if (i->rr) | |
287 | dns_resource_key_reduce(&i->rr->key, &i->key); | |
288 | ||
7e8e0422 LP |
289 | LIST_PREPEND(by_key, first, i); |
290 | assert_se(hashmap_replace(c->by_key, first->key, first) >= 0); | |
291 | } else { | |
292 | r = hashmap_put(c->by_key, i->key, i); | |
293 | if (r < 0) { | |
294 | prioq_remove(c->by_expiry, i, &i->prioq_idx); | |
295 | return r; | |
296 | } | |
322345fd LP |
297 | } |
298 | ||
7e8e0422 | 299 | return 0; |
322345fd LP |
300 | } |
301 | ||
faa133f3 LP |
302 | static DnsCacheItem* dns_cache_get(DnsCache *c, DnsResourceRecord *rr) { |
303 | DnsCacheItem *i; | |
304 | ||
305 | assert(c); | |
306 | assert(rr); | |
307 | ||
7e8e0422 | 308 | LIST_FOREACH(by_key, i, hashmap_get(c->by_key, rr->key)) |
3ef77d04 | 309 | if (i->rr && dns_resource_record_equal(i->rr, rr) > 0) |
faa133f3 LP |
310 | return i; |
311 | ||
312 | return NULL; | |
313 | } | |
314 | ||
d3760be0 | 315 | static usec_t calculate_until(DnsResourceRecord *rr, uint32_t nsec_ttl, usec_t timestamp, bool use_soa_minimum) { |
b211dc7e LP |
316 | uint32_t ttl; |
317 | usec_t u; | |
ee3d6aff LP |
318 | |
319 | assert(rr); | |
320 | ||
d3760be0 | 321 | ttl = MIN(rr->ttl, nsec_ttl); |
b211dc7e LP |
322 | if (rr->key->type == DNS_TYPE_SOA && use_soa_minimum) { |
323 | /* If this is a SOA RR, and it is requested, clamp to | |
324 | * the SOA's minimum field. This is used when we do | |
325 | * negative caching, to determine the TTL for the | |
326 | * negative caching entry. See RFC 2308, Section | |
327 | * 5. */ | |
ee3d6aff | 328 | |
b211dc7e LP |
329 | if (ttl > rr->soa.minimum) |
330 | ttl = rr->soa.minimum; | |
331 | } | |
332 | ||
333 | u = ttl * USEC_PER_SEC; | |
334 | if (u > CACHE_TTL_MAX_USEC) | |
335 | u = CACHE_TTL_MAX_USEC; | |
ee3d6aff LP |
336 | |
337 | if (rr->expiry != USEC_INFINITY) { | |
338 | usec_t left; | |
339 | ||
b211dc7e LP |
340 | /* Make use of the DNSSEC RRSIG expiry info, if we |
341 | * have it */ | |
ee3d6aff LP |
342 | |
343 | left = LESS_BY(rr->expiry, now(CLOCK_REALTIME)); | |
b211dc7e LP |
344 | if (u > left) |
345 | u = left; | |
ee3d6aff LP |
346 | } |
347 | ||
b211dc7e | 348 | return timestamp + u; |
ee3d6aff LP |
349 | } |
350 | ||
d2579eec LP |
351 | static void dns_cache_item_update_positive( |
352 | DnsCache *c, | |
353 | DnsCacheItem *i, | |
354 | DnsResourceRecord *rr, | |
775ae354 LP |
355 | DnsAnswer *answer, |
356 | DnsPacket *full_packet, | |
6f055e43 | 357 | uint64_t query_flags, |
d2579eec | 358 | bool shared_owner, |
775ae354 | 359 | DnssecResult dnssec_result, |
d2579eec | 360 | usec_t timestamp, |
06d12754 | 361 | int ifindex, |
d2579eec LP |
362 | int owner_family, |
363 | const union in_addr_union *owner_address) { | |
364 | ||
7e8e0422 LP |
365 | assert(c); |
366 | assert(i); | |
367 | assert(rr); | |
d2579eec | 368 | assert(owner_address); |
7e8e0422 LP |
369 | |
370 | i->type = DNS_CACHE_POSITIVE; | |
371 | ||
ece174c5 | 372 | if (!i->by_key_prev) |
7e8e0422 LP |
373 | /* We are the first item in the list, we need to |
374 | * update the key used in the hashmap */ | |
375 | ||
376 | assert_se(hashmap_replace(c->by_key, rr->key, i) >= 0); | |
7e8e0422 LP |
377 | |
378 | dns_resource_record_ref(rr); | |
379 | dns_resource_record_unref(i->rr); | |
380 | i->rr = rr; | |
381 | ||
382 | dns_resource_key_unref(i->key); | |
383 | i->key = dns_resource_key_ref(rr->key); | |
384 | ||
775ae354 LP |
385 | dns_answer_ref(answer); |
386 | dns_answer_unref(i->answer); | |
387 | i->answer = answer; | |
388 | ||
389 | dns_packet_ref(full_packet); | |
390 | dns_packet_unref(i->full_packet); | |
391 | i->full_packet = full_packet; | |
392 | ||
393 | i->until = calculate_until(rr, UINT32_MAX, timestamp, false); | |
6f055e43 | 394 | i->query_flags = query_flags & CACHEABLE_QUERY_FLAGS; |
d2579eec | 395 | i->shared_owner = shared_owner; |
775ae354 | 396 | i->dnssec_result = dnssec_result; |
d2579eec | 397 | |
06d12754 LP |
398 | i->ifindex = ifindex; |
399 | ||
d2579eec LP |
400 | i->owner_family = owner_family; |
401 | i->owner_address = *owner_address; | |
7e8e0422 LP |
402 | |
403 | prioq_reshuffle(c->by_expiry, i, &i->prioq_idx); | |
404 | } | |
405 | ||
a4076574 LP |
406 | static int dns_cache_put_positive( |
407 | DnsCache *c, | |
408 | DnsResourceRecord *rr, | |
775ae354 LP |
409 | DnsAnswer *answer, |
410 | DnsPacket *full_packet, | |
6f055e43 | 411 | uint64_t query_flags, |
d2579eec | 412 | bool shared_owner, |
775ae354 | 413 | DnssecResult dnssec_result, |
a4076574 | 414 | usec_t timestamp, |
06d12754 | 415 | int ifindex, |
a4076574 LP |
416 | int owner_family, |
417 | const union in_addr_union *owner_address) { | |
418 | ||
322345fd | 419 | _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; |
7e8e0422 | 420 | DnsCacheItem *existing; |
518a66ec | 421 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
a257f9d4 | 422 | int r, k; |
322345fd LP |
423 | |
424 | assert(c); | |
425 | assert(rr); | |
a4076574 | 426 | assert(owner_address); |
322345fd | 427 | |
222148b6 LP |
428 | /* Never cache pseudo RRs */ |
429 | if (dns_class_is_pseudo(rr->key->class)) | |
430 | return 0; | |
431 | if (dns_type_is_pseudo(rr->key->type)) | |
432 | return 0; | |
433 | ||
f5bdeb01 | 434 | /* New TTL is 0? Delete this specific entry... */ |
322345fd | 435 | if (rr->ttl <= 0) { |
f5bdeb01 | 436 | k = dns_cache_remove_by_rr(c, rr); |
202b76ae ZJS |
437 | log_debug("%s: %s", |
438 | k > 0 ? "Removed zero TTL entry from cache" : "Not caching zero TTL cache entry", | |
18665d1f | 439 | dns_resource_key_to_string(rr->key, key_str, sizeof key_str)); |
322345fd LP |
440 | return 0; |
441 | } | |
442 | ||
13e785f7 | 443 | /* Entry exists already? Update TTL, timestamp and owner */ |
322345fd LP |
444 | existing = dns_cache_get(c, rr); |
445 | if (existing) { | |
d2579eec LP |
446 | dns_cache_item_update_positive( |
447 | c, | |
448 | existing, | |
449 | rr, | |
775ae354 LP |
450 | answer, |
451 | full_packet, | |
6f055e43 | 452 | query_flags, |
d2579eec | 453 | shared_owner, |
775ae354 | 454 | dnssec_result, |
d2579eec | 455 | timestamp, |
06d12754 | 456 | ifindex, |
d2579eec LP |
457 | owner_family, |
458 | owner_address); | |
322345fd LP |
459 | return 0; |
460 | } | |
461 | ||
462 | /* Otherwise, add the new RR */ | |
623a4c97 | 463 | r = dns_cache_init(c); |
322345fd LP |
464 | if (r < 0) |
465 | return r; | |
466 | ||
7e8e0422 LP |
467 | dns_cache_make_space(c, 1); |
468 | ||
1ed31408 | 469 | i = new(DnsCacheItem, 1); |
7e8e0422 LP |
470 | if (!i) |
471 | return -ENOMEM; | |
472 | ||
1ed31408 LP |
473 | *i = (DnsCacheItem) { |
474 | .type = DNS_CACHE_POSITIVE, | |
475 | .key = dns_resource_key_ref(rr->key), | |
476 | .rr = dns_resource_record_ref(rr), | |
775ae354 LP |
477 | .answer = dns_answer_ref(answer), |
478 | .full_packet = dns_packet_ref(full_packet), | |
f5fbe71d | 479 | .until = calculate_until(rr, UINT32_MAX, timestamp, false), |
6f055e43 | 480 | .query_flags = query_flags & CACHEABLE_QUERY_FLAGS, |
1ed31408 | 481 | .shared_owner = shared_owner, |
775ae354 | 482 | .dnssec_result = dnssec_result, |
1ed31408 LP |
483 | .ifindex = ifindex, |
484 | .owner_family = owner_family, | |
485 | .owner_address = *owner_address, | |
486 | .prioq_idx = PRIOQ_IDX_NULL, | |
487 | }; | |
7e8e0422 LP |
488 | |
489 | r = dns_cache_link_item(c, i); | |
490 | if (r < 0) | |
491 | return r; | |
492 | ||
f1d34068 | 493 | if (DEBUG_LOGGING) { |
202b76ae | 494 | _cleanup_free_ char *t = NULL; |
518a66ec | 495 | char ifname[IF_NAMESIZE + 1]; |
202b76ae ZJS |
496 | |
497 | (void) in_addr_to_string(i->owner_family, &i->owner_address, &t); | |
498 | ||
43fc4baa | 499 | log_debug("Added positive %s %s%s cache entry for %s "USEC_FMT"s on %s/%s/%s", |
6f055e43 | 500 | FLAGS_SET(i->query_flags, SD_RESOLVED_AUTHENTICATED) ? "authenticated" : "unauthenticated", |
43fc4baa | 501 | FLAGS_SET(i->query_flags, SD_RESOLVED_CONFIDENTIAL) ? "confidential" : "non-confidential", |
202b76ae ZJS |
502 | i->shared_owner ? " shared" : "", |
503 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), | |
504 | (i->until - timestamp) / USEC_PER_SEC, | |
518a66ec | 505 | i->ifindex == 0 ? "*" : strna(format_ifname(i->ifindex, ifname)), |
202b76ae ZJS |
506 | af_to_name_short(i->owner_family), |
507 | strna(t)); | |
a257f9d4 | 508 | } |
6b34a6c9 | 509 | |
7e8e0422 LP |
510 | i = NULL; |
511 | return 0; | |
512 | } | |
513 | ||
a4076574 LP |
514 | static int dns_cache_put_negative( |
515 | DnsCache *c, | |
516 | DnsResourceKey *key, | |
517 | int rcode, | |
775ae354 LP |
518 | DnsAnswer *answer, |
519 | DnsPacket *full_packet, | |
6f055e43 | 520 | uint64_t query_flags, |
775ae354 | 521 | DnssecResult dnssec_result, |
d3760be0 | 522 | uint32_t nsec_ttl, |
a4076574 | 523 | usec_t timestamp, |
b211dc7e | 524 | DnsResourceRecord *soa, |
a4076574 LP |
525 | int owner_family, |
526 | const union in_addr_union *owner_address) { | |
527 | ||
7e8e0422 | 528 | _cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL; |
202b76ae | 529 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
7e8e0422 LP |
530 | int r; |
531 | ||
532 | assert(c); | |
533 | assert(key); | |
a4076574 | 534 | assert(owner_address); |
7e8e0422 | 535 | |
98b6be77 LP |
536 | /* Never cache pseudo RR keys. DNS_TYPE_ANY is particularly |
537 | * important to filter out as we use this as a pseudo-type for | |
538 | * NXDOMAIN entries */ | |
222148b6 | 539 | if (dns_class_is_pseudo(key->class)) |
ddf16339 | 540 | return 0; |
c33be4a6 | 541 | if (dns_type_is_pseudo(key->type)) |
ddf16339 | 542 | return 0; |
222148b6 | 543 | |
201d9958 LP |
544 | if (IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) { |
545 | if (!soa) | |
546 | return 0; | |
ddf16339 | 547 | |
201d9958 LP |
548 | /* For negative replies, check if we have a TTL of a SOA */ |
549 | if (nsec_ttl <= 0 || soa->soa.minimum <= 0 || soa->ttl <= 0) { | |
550 | log_debug("Not caching negative entry with zero SOA/NSEC/NSEC3 TTL: %s", | |
551 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
552 | return 0; | |
553 | } | |
554 | } else if (rcode != DNS_RCODE_SERVFAIL) | |
7e8e0422 LP |
555 | return 0; |
556 | ||
623a4c97 | 557 | r = dns_cache_init(c); |
322345fd LP |
558 | if (r < 0) |
559 | return r; | |
560 | ||
561 | dns_cache_make_space(c, 1); | |
562 | ||
1ed31408 | 563 | i = new(DnsCacheItem, 1); |
322345fd LP |
564 | if (!i) |
565 | return -ENOMEM; | |
566 | ||
1ed31408 LP |
567 | *i = (DnsCacheItem) { |
568 | .type = | |
569 | rcode == DNS_RCODE_SUCCESS ? DNS_CACHE_NODATA : | |
570 | rcode == DNS_RCODE_NXDOMAIN ? DNS_CACHE_NXDOMAIN : DNS_CACHE_RCODE, | |
6f055e43 | 571 | .query_flags = query_flags & CACHEABLE_QUERY_FLAGS, |
775ae354 | 572 | .dnssec_result = dnssec_result, |
1ed31408 LP |
573 | .owner_family = owner_family, |
574 | .owner_address = *owner_address, | |
575 | .prioq_idx = PRIOQ_IDX_NULL, | |
576 | .rcode = rcode, | |
775ae354 LP |
577 | .answer = dns_answer_ref(answer), |
578 | .full_packet = dns_packet_ref(full_packet), | |
1ed31408 | 579 | }; |
322345fd | 580 | |
eaa26948 LP |
581 | i->until = |
582 | i->type == DNS_CACHE_RCODE ? timestamp + CACHE_TTL_STRANGE_RCODE_USEC : | |
583 | calculate_until(soa, nsec_ttl, timestamp, true); | |
584 | ||
71e13669 TG |
585 | if (i->type == DNS_CACHE_NXDOMAIN) { |
586 | /* NXDOMAIN entries should apply equally to all types, so we use ANY as | |
587 | * a pseudo type for this purpose here. */ | |
1c02e7ba | 588 | i->key = dns_resource_key_new(key->class, DNS_TYPE_ANY, dns_resource_key_name(key)); |
71e13669 TG |
589 | if (!i->key) |
590 | return -ENOMEM; | |
a5444ca9 LP |
591 | |
592 | /* Make sure to remove any previous entry for this | |
593 | * specific ANY key. (For non-ANY keys the cache data | |
594 | * is already cleared by the caller.) Note that we | |
595 | * don't bother removing positive or NODATA cache | |
596 | * items in this case, because it would either be slow | |
597 | * or require explicit indexing by name */ | |
598 | dns_cache_remove_by_key(c, key); | |
71e13669 TG |
599 | } else |
600 | i->key = dns_resource_key_ref(key); | |
601 | ||
7e8e0422 | 602 | r = dns_cache_link_item(c, i); |
322345fd LP |
603 | if (r < 0) |
604 | return r; | |
605 | ||
202b76ae | 606 | log_debug("Added %s cache entry for %s "USEC_FMT"s", |
201d9958 | 607 | dns_cache_item_type_to_string(i), |
202b76ae ZJS |
608 | dns_resource_key_to_string(i->key, key_str, sizeof key_str), |
609 | (i->until - timestamp) / USEC_PER_SEC); | |
6b34a6c9 | 610 | |
322345fd | 611 | i = NULL; |
322345fd LP |
612 | return 0; |
613 | } | |
614 | ||
d2579eec LP |
615 | static void dns_cache_remove_previous( |
616 | DnsCache *c, | |
617 | DnsResourceKey *key, | |
618 | DnsAnswer *answer) { | |
619 | ||
620 | DnsResourceRecord *rr; | |
621 | DnsAnswerFlags flags; | |
622 | ||
623 | assert(c); | |
624 | ||
625 | /* First, if we were passed a key (i.e. on LLMNR/DNS, but | |
626 | * not on mDNS), delete all matching old RRs, so that we only | |
627 | * keep complete by_key in place. */ | |
628 | if (key) | |
2dda578f | 629 | dns_cache_remove_by_key(c, key); |
d2579eec LP |
630 | |
631 | /* Second, flush all entries matching the answer, unless this | |
632 | * is an RR that is explicitly marked to be "shared" between | |
633 | * peers (i.e. mDNS RRs without the flush-cache bit set). */ | |
634 | DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) { | |
635 | if ((flags & DNS_ANSWER_CACHEABLE) == 0) | |
636 | continue; | |
637 | ||
638 | if (flags & DNS_ANSWER_SHARED_OWNER) | |
639 | continue; | |
640 | ||
2dda578f | 641 | dns_cache_remove_by_key(c, rr->key); |
d2579eec LP |
642 | } |
643 | } | |
644 | ||
f6618dcd LP |
645 | static bool rr_eligible(DnsResourceRecord *rr) { |
646 | assert(rr); | |
647 | ||
648 | /* When we see an NSEC/NSEC3 RR, we'll only cache it if it is from the lower zone, not the upper zone, since | |
649 | * that's where the interesting bits are (with exception of DS RRs). Of course, this way we cannot derive DS | |
650 | * existence from any cached NSEC/NSEC3, but that should be fine. */ | |
651 | ||
652 | switch (rr->key->type) { | |
653 | ||
654 | case DNS_TYPE_NSEC: | |
655 | return !bitmap_isset(rr->nsec.types, DNS_TYPE_NS) || | |
656 | bitmap_isset(rr->nsec.types, DNS_TYPE_SOA); | |
657 | ||
658 | case DNS_TYPE_NSEC3: | |
659 | return !bitmap_isset(rr->nsec3.types, DNS_TYPE_NS) || | |
660 | bitmap_isset(rr->nsec3.types, DNS_TYPE_SOA); | |
661 | ||
662 | default: | |
663 | return true; | |
664 | } | |
665 | } | |
666 | ||
a4076574 LP |
667 | int dns_cache_put( |
668 | DnsCache *c, | |
37d7a7d9 | 669 | DnsCacheMode cache_mode, |
8e427d9b | 670 | DnsResourceKey *key, |
a4076574 LP |
671 | int rcode, |
672 | DnsAnswer *answer, | |
775ae354 | 673 | DnsPacket *full_packet, |
6f055e43 | 674 | uint64_t query_flags, |
775ae354 | 675 | DnssecResult dnssec_result, |
d3760be0 | 676 | uint32_t nsec_ttl, |
a4076574 LP |
677 | int owner_family, |
678 | const union in_addr_union *owner_address) { | |
679 | ||
9c5fcb8a | 680 | DnsResourceRecord *soa = NULL; |
201d9958 | 681 | bool weird_rcode = false; |
9c5fcb8a | 682 | DnsAnswerItem *item; |
105e1512 LP |
683 | DnsAnswerFlags flags; |
684 | unsigned cache_keys; | |
43475909 | 685 | usec_t timestamp; |
9c5fcb8a | 686 | int r; |
322345fd LP |
687 | |
688 | assert(c); | |
d2579eec | 689 | assert(owner_address); |
322345fd | 690 | |
d2579eec | 691 | dns_cache_remove_previous(c, key, answer); |
0ec7c46e | 692 | |
201d9958 LP |
693 | /* We only care for positive replies and NXDOMAINs, on all other replies we will simply flush the respective |
694 | * entries, and that's it. (Well, with one further exception: since some DNS zones (akamai!) return SERVFAIL | |
695 | * consistently for some lookups, and forwarders tend to propagate that we'll cache that too, but only for a | |
696 | * short time.) */ | |
6ff01a0d | 697 | |
201d9958 | 698 | if (IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN)) { |
201d9958 | 699 | if (dns_answer_size(answer) <= 0) { |
e55fc5b0 YW |
700 | if (key) { |
701 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; | |
201d9958 | 702 | |
e55fc5b0 YW |
703 | log_debug("Not caching negative entry without a SOA record: %s", |
704 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
705 | } | |
775ae354 | 706 | |
201d9958 LP |
707 | return 0; |
708 | } | |
709 | ||
710 | } else { | |
711 | /* Only cache SERVFAIL as "weird" rcode for now. We can add more later, should that turn out to be | |
712 | * beneficial. */ | |
713 | if (rcode != DNS_RCODE_SERVFAIL) | |
714 | return 0; | |
715 | ||
716 | weird_rcode = true; | |
c3cb6dc2 | 717 | } |
0ec7c46e | 718 | |
ea207b63 | 719 | cache_keys = dns_answer_size(answer); |
8e427d9b | 720 | if (key) |
313cefa1 | 721 | cache_keys++; |
eff91ee0 | 722 | |
7e8e0422 | 723 | /* Make some space for our new entries */ |
eff91ee0 | 724 | dns_cache_make_space(c, cache_keys); |
322345fd | 725 | |
43475909 | 726 | timestamp = now(clock_boottime_or_monotonic()); |
322345fd | 727 | |
7e8e0422 | 728 | /* Second, add in positive entries for all contained RRs */ |
9c5fcb8a | 729 | DNS_ANSWER_FOREACH_ITEM(item, answer) { |
775ae354 LP |
730 | int primary = false; |
731 | ||
732 | if (!FLAGS_SET(item->flags, DNS_ANSWER_CACHEABLE) || | |
9c5fcb8a | 733 | !rr_eligible(item->rr)) |
f6618dcd LP |
734 | continue; |
735 | ||
775ae354 LP |
736 | if (key) { |
737 | /* We store the auxiliary RRs and packet data in the cache only if they were in | |
738 | * direct response to the original query. If we cache an RR we also received, and | |
739 | * that is just auxiliary information we can't use the data, hence don't. */ | |
740 | ||
741 | primary = dns_resource_key_match_rr(key, item->rr, NULL); | |
742 | if (primary < 0) | |
743 | return primary; | |
744 | if (primary == 0) { | |
745 | primary = dns_resource_key_match_cname_or_dname(key, item->rr->key, NULL); | |
746 | if (primary < 0) | |
747 | return primary; | |
748 | } | |
749 | } | |
750 | ||
751 | if (!primary) { | |
752 | DnsCacheItem *first; | |
753 | ||
754 | /* Do not replace existing cache items for primary lookups with non-primary | |
755 | * data. After all the primary lookup data is a lot more useful. */ | |
756 | first = hashmap_get(c->by_key, item->rr->key); | |
757 | if (first && DNS_CACHE_ITEM_IS_PRIMARY(first)) | |
758 | return 0; | |
759 | } | |
760 | ||
d2579eec LP |
761 | r = dns_cache_put_positive( |
762 | c, | |
9c5fcb8a | 763 | item->rr, |
775ae354 LP |
764 | primary ? answer : NULL, |
765 | primary ? full_packet : NULL, | |
43fc4baa LP |
766 | ((item->flags & DNS_ANSWER_AUTHENTICATED) ? SD_RESOLVED_AUTHENTICATED : 0) | |
767 | (query_flags & SD_RESOLVED_CONFIDENTIAL), | |
9c5fcb8a | 768 | item->flags & DNS_ANSWER_SHARED_OWNER, |
775ae354 | 769 | dnssec_result, |
d2579eec | 770 | timestamp, |
9c5fcb8a | 771 | item->ifindex, |
775ae354 LP |
772 | owner_family, |
773 | owner_address); | |
7e8e0422 LP |
774 | if (r < 0) |
775 | goto fail; | |
776 | } | |
777 | ||
d2579eec | 778 | if (!key) /* mDNS doesn't know negative caching, really */ |
eff91ee0 DM |
779 | return 0; |
780 | ||
8e427d9b | 781 | /* Third, add in negative entries if the key has no RR */ |
105e1512 | 782 | r = dns_answer_match_key(answer, key, NULL); |
8e427d9b TG |
783 | if (r < 0) |
784 | goto fail; | |
785 | if (r > 0) | |
786 | return 0; | |
7e8e0422 | 787 | |
5d27351f TG |
788 | /* But not if it has a matching CNAME/DNAME (the negative |
789 | * caching will be done on the canonical name, not on the | |
790 | * alias) */ | |
105e1512 | 791 | r = dns_answer_find_cname_or_dname(answer, key, NULL, NULL); |
5d27351f TG |
792 | if (r < 0) |
793 | goto fail; | |
794 | if (r > 0) | |
795 | return 0; | |
796 | ||
201d9958 LP |
797 | /* See https://tools.ietf.org/html/rfc2308, which say that a matching SOA record in the packet is used to |
798 | * enable negative caching. We apply one exception though: if we are about to cache a weird rcode we do so | |
799 | * regardless of a SOA. */ | |
fd009cd8 | 800 | r = dns_answer_find_soa(answer, key, &soa, &flags); |
8e427d9b TG |
801 | if (r < 0) |
802 | goto fail; | |
201d9958 | 803 | if (r == 0 && !weird_rcode) |
fd009cd8 | 804 | return 0; |
201d9958 LP |
805 | if (r > 0) { |
806 | /* Refuse using the SOA data if it is unsigned, but the key is | |
807 | * signed */ | |
6f055e43 LP |
808 | if (FLAGS_SET(query_flags, SD_RESOLVED_AUTHENTICATED) && |
809 | (flags & DNS_ANSWER_AUTHENTICATED) == 0) | |
201d9958 LP |
810 | return 0; |
811 | } | |
fd009cd8 | 812 | |
37d7a7d9 JN |
813 | if (cache_mode == DNS_CACHE_MODE_NO_NEGATIVE) { |
814 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; | |
815 | log_debug("Not caching negative entry for: %s, cache mode set to no-negative", | |
816 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
817 | return 0; | |
818 | } | |
819 | ||
d2579eec LP |
820 | r = dns_cache_put_negative( |
821 | c, | |
822 | key, | |
823 | rcode, | |
775ae354 LP |
824 | answer, |
825 | full_packet, | |
6f055e43 | 826 | query_flags, |
775ae354 | 827 | dnssec_result, |
d3760be0 | 828 | nsec_ttl, |
d2579eec | 829 | timestamp, |
b211dc7e | 830 | soa, |
d2579eec | 831 | owner_family, owner_address); |
8e427d9b TG |
832 | if (r < 0) |
833 | goto fail; | |
322345fd LP |
834 | |
835 | return 0; | |
836 | ||
837 | fail: | |
838 | /* Adding all RRs failed. Let's clean up what we already | |
839 | * added, just in case */ | |
840 | ||
8e427d9b | 841 | if (key) |
2dda578f | 842 | dns_cache_remove_by_key(c, key); |
eff91ee0 | 843 | |
9c5fcb8a LP |
844 | DNS_ANSWER_FOREACH_ITEM(item, answer) { |
845 | if ((item->flags & DNS_ANSWER_CACHEABLE) == 0) | |
105e1512 LP |
846 | continue; |
847 | ||
9c5fcb8a | 848 | dns_cache_remove_by_key(c, item->rr->key); |
105e1512 | 849 | } |
322345fd LP |
850 | |
851 | return r; | |
852 | } | |
853 | ||
37da8931 | 854 | static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, DnsResourceKey *k) { |
58db254a LP |
855 | DnsCacheItem *i; |
856 | const char *n; | |
857 | int r; | |
5643c00a TG |
858 | |
859 | assert(c); | |
860 | assert(k); | |
861 | ||
58db254a LP |
862 | /* If we hit some OOM error, or suchlike, we don't care too |
863 | * much, after all this is just a cache */ | |
864 | ||
5643c00a | 865 | i = hashmap_get(c->by_key, k); |
d7ce6c94 | 866 | if (i) |
37da8931 LP |
867 | return i; |
868 | ||
1c02e7ba | 869 | n = dns_resource_key_name(k); |
37da8931 | 870 | |
71e13669 TG |
871 | /* Check if we have an NXDOMAIN cache item for the name, notice that we use |
872 | * the pseudo-type ANY for NXDOMAIN cache items. */ | |
873 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_ANY, n)); | |
874 | if (i && i->type == DNS_CACHE_NXDOMAIN) | |
875 | return i; | |
876 | ||
d3c7e913 | 877 | if (dns_type_may_redirect(k->type)) { |
d7ce6c94 TG |
878 | /* Check if we have a CNAME record instead */ |
879 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_CNAME, n)); | |
3740146a | 880 | if (i && i->type != DNS_CACHE_NODATA) |
d7ce6c94 | 881 | return i; |
5643c00a | 882 | |
d7ce6c94 TG |
883 | /* OK, let's look for cached DNAME records. */ |
884 | for (;;) { | |
d7ce6c94 TG |
885 | if (isempty(n)) |
886 | return NULL; | |
887 | ||
888 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_DNAME, n)); | |
3740146a | 889 | if (i && i->type != DNS_CACHE_NODATA) |
d7ce6c94 | 890 | return i; |
58db254a | 891 | |
d7ce6c94 | 892 | /* Jump one label ahead */ |
950b692b | 893 | r = dns_name_parent(&n); |
d7ce6c94 TG |
894 | if (r <= 0) |
895 | return NULL; | |
896 | } | |
897 | } | |
5643c00a | 898 | |
950b692b | 899 | if (k->type != DNS_TYPE_NSEC) { |
d7ce6c94 TG |
900 | /* Check if we have an NSEC record instead for the name. */ |
901 | i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_NSEC, n)); | |
58db254a LP |
902 | if (i) |
903 | return i; | |
58db254a LP |
904 | } |
905 | ||
906 | return NULL; | |
5643c00a TG |
907 | } |
908 | ||
775ae354 LP |
909 | static int answer_add_clamp_ttl( |
910 | DnsAnswer **answer, | |
911 | DnsResourceRecord *rr, | |
912 | int ifindex, | |
913 | DnsAnswerFlags answer_flags, | |
914 | DnsResourceRecord *rrsig, | |
915 | uint64_t query_flags, | |
916 | usec_t until, | |
917 | usec_t current) { | |
918 | ||
919 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *patched = NULL, *patched_rrsig = NULL; | |
920 | int r; | |
921 | ||
922 | assert(answer); | |
923 | assert(rr); | |
924 | ||
925 | if (FLAGS_SET(query_flags, SD_RESOLVED_CLAMP_TTL)) { | |
926 | patched = dns_resource_record_ref(rr); | |
927 | ||
928 | r = dns_resource_record_clamp_ttl(&patched, LESS_BY(until, current) / USEC_PER_SEC); | |
929 | if (r < 0) | |
930 | return r; | |
931 | ||
932 | rr = patched; | |
933 | ||
934 | if (rrsig) { | |
935 | patched_rrsig = dns_resource_record_ref(rrsig); | |
936 | r = dns_resource_record_clamp_ttl(&patched_rrsig, LESS_BY(until, current) / USEC_PER_SEC); | |
937 | if (r < 0) | |
938 | return r; | |
939 | ||
940 | rrsig = patched_rrsig; | |
941 | } | |
942 | } | |
943 | ||
944 | r = dns_answer_add_extend(answer, rr, ifindex, answer_flags, rrsig); | |
945 | if (r < 0) | |
946 | return r; | |
947 | ||
948 | return 0; | |
949 | } | |
950 | ||
951 | int dns_cache_lookup( | |
952 | DnsCache *c, | |
953 | DnsResourceKey *key, | |
954 | uint64_t query_flags, | |
955 | int *ret_rcode, | |
956 | DnsAnswer **ret_answer, | |
957 | DnsPacket **ret_full_packet, | |
6f055e43 | 958 | uint64_t *ret_query_flags, |
775ae354 LP |
959 | DnssecResult *ret_dnssec_result) { |
960 | ||
961 | _cleanup_(dns_packet_unrefp) DnsPacket *full_packet = NULL; | |
faa133f3 | 962 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; |
202b76ae | 963 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
f52e61da | 964 | unsigned n = 0; |
322345fd | 965 | int r; |
7e8e0422 | 966 | bool nxdomain = false; |
931851e8 | 967 | DnsCacheItem *j, *first, *nsec = NULL; |
43fc4baa | 968 | bool have_authenticated = false, have_non_authenticated = false, have_confidential = false, have_non_confidential = false; |
17c8de63 | 969 | usec_t current; |
201d9958 | 970 | int found_rcode = -1; |
775ae354 LP |
971 | DnssecResult dnssec_result = -1; |
972 | int have_dnssec_result = -1; | |
322345fd LP |
973 | |
974 | assert(c); | |
f52e61da | 975 | assert(key); |
322345fd | 976 | |
202b76ae | 977 | if (key->type == DNS_TYPE_ANY || key->class == DNS_CLASS_ANY) { |
775ae354 LP |
978 | /* If we have ANY lookups we don't use the cache, so that the caller refreshes via the |
979 | * network. */ | |
322345fd | 980 | |
202b76ae ZJS |
981 | log_debug("Ignoring cache for ANY lookup: %s", |
982 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
775ae354 | 983 | goto miss; |
f52e61da | 984 | } |
6b34a6c9 | 985 | |
37da8931 | 986 | first = dns_cache_get_by_key_follow_cname_dname_nsec(c, key); |
f52e61da LP |
987 | if (!first) { |
988 | /* If one question cannot be answered we need to refresh */ | |
ddf16339 | 989 | |
202b76ae ZJS |
990 | log_debug("Cache miss for %s", |
991 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
775ae354 LP |
992 | goto miss; |
993 | } | |
6b34a6c9 | 994 | |
775ae354 LP |
995 | if (FLAGS_SET(query_flags, SD_RESOLVED_CLAMP_TTL)) |
996 | current = now(clock_boottime_or_monotonic()); | |
a150ff5e | 997 | |
775ae354 LP |
998 | LIST_FOREACH(by_key, j, first) { |
999 | /* If the caller doesn't allow us to answer questions from cache data learned from | |
1000 | * "side-effect", skip this entry. */ | |
1001 | if (FLAGS_SET(query_flags, SD_RESOLVED_REQUIRE_PRIMARY) && | |
1002 | !DNS_CACHE_ITEM_IS_PRIMARY(j)) { | |
1003 | log_debug("Primary answer was requested for cache lookup for %s, which we don't have.", | |
1004 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
2d4a4e14 | 1005 | |
775ae354 LP |
1006 | goto miss; |
1007 | } | |
6b34a6c9 | 1008 | |
775ae354 LP |
1009 | if (j->type == DNS_CACHE_NXDOMAIN) |
1010 | nxdomain = true; | |
1011 | else if (j->type == DNS_CACHE_RCODE) | |
1012 | found_rcode = j->rcode; | |
1013 | else if (j->rr) { | |
37da8931 | 1014 | if (j->rr->key->type == DNS_TYPE_NSEC) |
931851e8 LP |
1015 | nsec = j; |
1016 | ||
f52e61da | 1017 | n++; |
775ae354 | 1018 | } |
931851e8 | 1019 | |
6f055e43 | 1020 | if (FLAGS_SET(j->query_flags, SD_RESOLVED_AUTHENTICATED)) |
931851e8 LP |
1021 | have_authenticated = true; |
1022 | else | |
1023 | have_non_authenticated = true; | |
775ae354 | 1024 | |
43fc4baa LP |
1025 | if (FLAGS_SET(j->query_flags, SD_RESOLVED_CONFIDENTIAL)) |
1026 | have_confidential = true; | |
1027 | else | |
1028 | have_non_confidential = true; | |
1029 | ||
775ae354 LP |
1030 | if (j->dnssec_result < 0) { |
1031 | have_dnssec_result = false; /* an entry without dnssec result? then invalidate things for good */ | |
1032 | dnssec_result = _DNSSEC_RESULT_INVALID; | |
1033 | } else if (have_dnssec_result < 0) { | |
1034 | have_dnssec_result = true; /* So far no result seen, let's pick this one up */ | |
1035 | dnssec_result = j->dnssec_result; | |
1036 | } else if (have_dnssec_result > 0 && j->dnssec_result != dnssec_result) { | |
1037 | have_dnssec_result = false; /* conflicting result seen? then invalidate for good */ | |
1038 | dnssec_result = _DNSSEC_RESULT_INVALID; | |
1039 | } | |
1040 | ||
1041 | /* Append the answer RRs to our answer. Ideally we have the answer object, which we | |
1042 | * preferably use. But if the cached entry was generated as "side-effect" of a reply, | |
1043 | * i.e. from validated auxiliary records rather than from the main reply, then we use the | |
1044 | * individual RRs only instead. */ | |
1045 | if (j->answer) { | |
1046 | ||
1047 | /* Minor optimization, if the full answer object of this and the previous RR is the | |
1048 | * same, don't bother adding it again. Typically we store a full RRset here, hence | |
1049 | * that should be the case. */ | |
1050 | if (!j->by_key_prev || j->answer != j->by_key_prev->answer) { | |
1051 | DnsAnswerItem *item; | |
1052 | ||
1053 | DNS_ANSWER_FOREACH_ITEM(item, j->answer) { | |
1054 | r = answer_add_clamp_ttl(&answer, item->rr, item->ifindex, item->flags, item->rrsig, query_flags, j->until, current); | |
1055 | if (r < 0) | |
1056 | return r; | |
1057 | } | |
1058 | } | |
1059 | ||
1060 | } else if (j->rr) { | |
6f055e43 LP |
1061 | r = answer_add_clamp_ttl(&answer, |
1062 | j->rr, | |
1063 | j->ifindex, | |
1064 | FLAGS_SET(j->query_flags, SD_RESOLVED_AUTHENTICATED) ? DNS_ANSWER_AUTHENTICATED : 0, | |
1065 | NULL, | |
1066 | query_flags, | |
1067 | j->until, | |
1068 | current); | |
775ae354 LP |
1069 | if (r < 0) |
1070 | return r; | |
1071 | } | |
1072 | ||
1073 | /* We'll return any packet we have for this. Typically all cache entries for the same key | |
1074 | * should come from the same packet anyway, hence it doesn't really matter which packet we | |
1075 | * return here, they should all resolve to the same anyway. */ | |
1076 | if (!full_packet && j->full_packet) | |
1077 | full_packet = dns_packet_ref(j->full_packet); | |
f52e61da | 1078 | } |
6b34a6c9 | 1079 | |
201d9958 LP |
1080 | if (found_rcode >= 0) { |
1081 | log_debug("RCODE %s cache hit for %s", | |
1082 | dns_rcode_to_string(found_rcode), | |
1083 | dns_resource_key_to_string(key, key_str, sizeof(key_str))); | |
1084 | ||
775ae354 LP |
1085 | if (ret_rcode) |
1086 | *ret_rcode = found_rcode; | |
1087 | if (ret_answer) | |
1088 | *ret_answer = TAKE_PTR(answer); | |
1089 | if (ret_full_packet) | |
1090 | *ret_full_packet = TAKE_PTR(full_packet); | |
6f055e43 LP |
1091 | if (ret_query_flags) |
1092 | *ret_query_flags = 0; | |
775ae354 LP |
1093 | if (ret_dnssec_result) |
1094 | *ret_dnssec_result = dnssec_result; | |
201d9958 LP |
1095 | |
1096 | c->n_hit++; | |
1097 | return 1; | |
1098 | } | |
1099 | ||
f6618dcd | 1100 | if (nsec && !IN_SET(key->type, DNS_TYPE_NSEC, DNS_TYPE_DS)) { |
775ae354 LP |
1101 | /* Note that we won't derive information for DS RRs from an NSEC, because we only cache NSEC |
1102 | * RRs from the lower-zone of a zone cut, but the DS RRs are on the upper zone. */ | |
f6618dcd | 1103 | |
202b76ae ZJS |
1104 | log_debug("NSEC NODATA cache hit for %s", |
1105 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
37da8931 | 1106 | |
775ae354 LP |
1107 | /* We only found an NSEC record that matches our name. If it says the type doesn't exist |
1108 | * report NODATA. Otherwise report a cache miss. */ | |
37da8931 | 1109 | |
775ae354 LP |
1110 | if (ret_rcode) |
1111 | *ret_rcode = DNS_RCODE_SUCCESS; | |
1112 | if (ret_answer) | |
1113 | *ret_answer = TAKE_PTR(answer); | |
1114 | if (ret_full_packet) | |
1115 | *ret_full_packet = TAKE_PTR(full_packet); | |
6f055e43 LP |
1116 | if (ret_query_flags) |
1117 | *ret_query_flags = nsec->query_flags; | |
775ae354 LP |
1118 | if (ret_dnssec_result) |
1119 | *ret_dnssec_result = nsec->dnssec_result; | |
37da8931 | 1120 | |
a150ff5e LP |
1121 | if (!bitmap_isset(nsec->rr->nsec.types, key->type) && |
1122 | !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_CNAME) && | |
1123 | !bitmap_isset(nsec->rr->nsec.types, DNS_TYPE_DNAME)) { | |
1124 | c->n_hit++; | |
1125 | return 1; | |
1126 | } | |
1127 | ||
1128 | c->n_miss++; | |
1129 | return 0; | |
37da8931 LP |
1130 | } |
1131 | ||
202b76ae ZJS |
1132 | log_debug("%s cache hit for %s", |
1133 | n > 0 ? "Positive" : | |
1134 | nxdomain ? "NXDOMAIN" : "NODATA", | |
1135 | dns_resource_key_to_string(key, key_str, sizeof key_str)); | |
faa133f3 | 1136 | |
7e8e0422 | 1137 | if (n <= 0) { |
a150ff5e LP |
1138 | c->n_hit++; |
1139 | ||
775ae354 LP |
1140 | if (ret_rcode) |
1141 | *ret_rcode = nxdomain ? DNS_RCODE_NXDOMAIN : DNS_RCODE_SUCCESS; | |
1142 | if (ret_answer) | |
1143 | *ret_answer = TAKE_PTR(answer); | |
1144 | if (ret_full_packet) | |
1145 | *ret_full_packet = TAKE_PTR(full_packet); | |
6f055e43 | 1146 | if (ret_query_flags) |
43fc4baa LP |
1147 | *ret_query_flags = |
1148 | ((have_authenticated && !have_non_authenticated) ? SD_RESOLVED_AUTHENTICATED : 0) | | |
1149 | ((have_confidential && !have_non_confidential) ? SD_RESOLVED_CONFIDENTIAL : 0); | |
775ae354 LP |
1150 | if (ret_dnssec_result) |
1151 | *ret_dnssec_result = dnssec_result; | |
17c8de63 | 1152 | |
775ae354 | 1153 | return 1; |
322345fd LP |
1154 | } |
1155 | ||
a150ff5e LP |
1156 | c->n_hit++; |
1157 | ||
775ae354 LP |
1158 | if (ret_rcode) |
1159 | *ret_rcode = DNS_RCODE_SUCCESS; | |
1160 | if (ret_answer) | |
1161 | *ret_answer = TAKE_PTR(answer); | |
1162 | if (ret_full_packet) | |
1163 | *ret_full_packet = TAKE_PTR(full_packet); | |
6f055e43 | 1164 | if (ret_query_flags) |
43fc4baa LP |
1165 | *ret_query_flags = |
1166 | ((have_authenticated && !have_non_authenticated) ? SD_RESOLVED_AUTHENTICATED : 0) | | |
1167 | ((have_confidential && !have_non_confidential) ? SD_RESOLVED_CONFIDENTIAL : 0); | |
775ae354 LP |
1168 | if (ret_dnssec_result) |
1169 | *ret_dnssec_result = dnssec_result; | |
faa133f3 LP |
1170 | |
1171 | return n; | |
775ae354 LP |
1172 | |
1173 | miss: | |
1174 | if (ret_rcode) | |
1175 | *ret_rcode = DNS_RCODE_SUCCESS; | |
1176 | if (ret_answer) | |
1177 | *ret_answer = NULL; | |
1178 | if (ret_full_packet) | |
1179 | *ret_full_packet = NULL; | |
6f055e43 LP |
1180 | if (ret_query_flags) |
1181 | *ret_query_flags = 0; | |
775ae354 LP |
1182 | if (ret_dnssec_result) |
1183 | *ret_dnssec_result = _DNSSEC_RESULT_INVALID; | |
1184 | ||
1185 | c->n_miss++; | |
1186 | return 0; | |
322345fd | 1187 | } |
a4076574 LP |
1188 | |
1189 | int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_family, const union in_addr_union *owner_address) { | |
1190 | DnsCacheItem *i, *first; | |
1191 | bool same_owner = true; | |
1192 | ||
1193 | assert(cache); | |
1194 | assert(rr); | |
1195 | ||
1196 | dns_cache_prune(cache); | |
1197 | ||
1198 | /* See if there's a cache entry for the same key. If there | |
1199 | * isn't there's no conflict */ | |
1200 | first = hashmap_get(cache->by_key, rr->key); | |
1201 | if (!first) | |
1202 | return 0; | |
1203 | ||
1204 | /* See if the RR key is owned by the same owner, if so, there | |
1205 | * isn't a conflict either */ | |
1206 | LIST_FOREACH(by_key, i, first) { | |
1207 | if (i->owner_family != owner_family || | |
1208 | !in_addr_equal(owner_family, &i->owner_address, owner_address)) { | |
1209 | same_owner = false; | |
1210 | break; | |
1211 | } | |
1212 | } | |
1213 | if (same_owner) | |
1214 | return 0; | |
1215 | ||
1216 | /* See if there's the exact same RR in the cache. If yes, then | |
1217 | * there's no conflict. */ | |
1218 | if (dns_cache_get(cache, rr)) | |
1219 | return 0; | |
1220 | ||
1221 | /* There's a conflict */ | |
1222 | return 1; | |
1223 | } | |
4d506d6b | 1224 | |
7778dfff DM |
1225 | int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p) { |
1226 | unsigned ancount = 0; | |
7778dfff DM |
1227 | DnsCacheItem *i; |
1228 | int r; | |
1229 | ||
1230 | assert(cache); | |
261f3673 | 1231 | assert(p); |
7778dfff | 1232 | |
90e74a66 | 1233 | HASHMAP_FOREACH(i, cache->by_key) { |
7778dfff DM |
1234 | DnsCacheItem *j; |
1235 | ||
1236 | LIST_FOREACH(by_key, j, i) { | |
7778dfff DM |
1237 | if (!j->rr) |
1238 | continue; | |
1239 | ||
d2579eec | 1240 | if (!j->shared_owner) |
7778dfff DM |
1241 | continue; |
1242 | ||
58ab31d5 | 1243 | r = dns_packet_append_rr(p, j->rr, 0, NULL, NULL); |
261f3673 DM |
1244 | if (r == -EMSGSIZE && p->protocol == DNS_PROTOCOL_MDNS) { |
1245 | /* For mDNS, if we're unable to stuff all known answers into the given packet, | |
1246 | * allocate a new one, push the RR into that one and link it to the current one. | |
1247 | */ | |
1248 | ||
1249 | DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); | |
1250 | ancount = 0; | |
1251 | ||
1252 | r = dns_packet_new_query(&p->more, p->protocol, 0, true); | |
1253 | if (r < 0) | |
1254 | return r; | |
1255 | ||
1256 | /* continue with new packet */ | |
1257 | p = p->more; | |
58ab31d5 | 1258 | r = dns_packet_append_rr(p, j->rr, 0, NULL, NULL); |
261f3673 DM |
1259 | } |
1260 | ||
7778dfff DM |
1261 | if (r < 0) |
1262 | return r; | |
1263 | ||
313cefa1 | 1264 | ancount++; |
7778dfff DM |
1265 | } |
1266 | } | |
1267 | ||
1268 | DNS_PACKET_HEADER(p)->ancount = htobe16(ancount); | |
1269 | ||
1270 | return 0; | |
1271 | } | |
1272 | ||
ca9fab88 | 1273 | void dns_cache_dump(DnsCache *cache, FILE *f) { |
4d506d6b | 1274 | DnsCacheItem *i; |
4d506d6b LP |
1275 | |
1276 | if (!cache) | |
1277 | return; | |
1278 | ||
1279 | if (!f) | |
1280 | f = stdout; | |
1281 | ||
90e74a66 | 1282 | HASHMAP_FOREACH(i, cache->by_key) { |
4d506d6b LP |
1283 | DnsCacheItem *j; |
1284 | ||
1285 | LIST_FOREACH(by_key, j, i) { | |
4d506d6b LP |
1286 | |
1287 | fputc('\t', f); | |
1288 | ||
1289 | if (j->rr) { | |
7b50eb2e LP |
1290 | const char *t; |
1291 | t = dns_resource_record_to_string(j->rr); | |
1292 | if (!t) { | |
4d506d6b LP |
1293 | log_oom(); |
1294 | continue; | |
1295 | } | |
1296 | ||
1297 | fputs(t, f); | |
1298 | fputc('\n', f); | |
1299 | } else { | |
202b76ae | 1300 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
4d506d6b | 1301 | |
202b76ae | 1302 | fputs(dns_resource_key_to_string(j->key, key_str, sizeof key_str), f); |
4d506d6b | 1303 | fputs(" -- ", f); |
201d9958 | 1304 | fputs(dns_cache_item_type_to_string(j), f); |
4d506d6b LP |
1305 | fputc('\n', f); |
1306 | } | |
1307 | } | |
1308 | } | |
1309 | } | |
1310 | ||
1311 | bool dns_cache_is_empty(DnsCache *cache) { | |
1312 | if (!cache) | |
1313 | return true; | |
1314 | ||
1315 | return hashmap_isempty(cache->by_key); | |
1316 | } | |
a150ff5e LP |
1317 | |
1318 | unsigned dns_cache_size(DnsCache *cache) { | |
1319 | if (!cache) | |
1320 | return 0; | |
1321 | ||
1322 | return hashmap_size(cache->by_key); | |
1323 | } |