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74b2466e LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
ad867662 LP |
22 | #include <netinet/tcp.h> |
23 | ||
46f08bea | 24 | #include "af-list.h" |
b5efdb8a | 25 | #include "alloc-util.h" |
4ad7f276 | 26 | #include "dns-domain.h" |
3ffd4af2 LP |
27 | #include "fd-util.h" |
28 | #include "hostname-util.h" | |
29 | #include "missing.h" | |
30 | #include "random-util.h" | |
74b2466e | 31 | #include "resolved-dns-scope.h" |
3ffd4af2 LP |
32 | #include "resolved-llmnr.h" |
33 | #include "socket-util.h" | |
34 | #include "strv.h" | |
74b2466e | 35 | |
aea2429d LP |
36 | #define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC) |
37 | #define MULTICAST_RATELIMIT_BURST 1000 | |
38 | ||
9df3ba6c TG |
39 | /* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */ |
40 | #define MULTICAST_RESEND_TIMEOUT_MIN_USEC (100 * USEC_PER_MSEC) | |
41 | #define MULTICAST_RESEND_TIMEOUT_MAX_USEC (1 * USEC_PER_SEC) | |
42 | ||
0dd25fb9 | 43 | int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) { |
74b2466e LP |
44 | DnsScope *s; |
45 | ||
46 | assert(m); | |
47 | assert(ret); | |
48 | ||
49 | s = new0(DnsScope, 1); | |
50 | if (!s) | |
51 | return -ENOMEM; | |
52 | ||
53 | s->manager = m; | |
1716f6dc LP |
54 | s->link = l; |
55 | s->protocol = protocol; | |
56 | s->family = family; | |
9df3ba6c | 57 | s->resend_timeout = MULTICAST_RESEND_TIMEOUT_MIN_USEC; |
74b2466e LP |
58 | |
59 | LIST_PREPEND(scopes, m->dns_scopes, s); | |
60 | ||
1716f6dc LP |
61 | dns_scope_llmnr_membership(s, true); |
62 | ||
46f08bea | 63 | log_debug("New scope on link %s, protocol %s, family %s", l ? l->name : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family)); |
1716f6dc | 64 | |
aea2429d LP |
65 | /* Enforce ratelimiting for the multicast protocols */ |
66 | RATELIMIT_INIT(s->ratelimit, MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST); | |
67 | ||
74b2466e LP |
68 | *ret = s; |
69 | return 0; | |
70 | } | |
71 | ||
72 | DnsScope* dns_scope_free(DnsScope *s) { | |
ec2c5e43 | 73 | DnsTransaction *t; |
a4076574 | 74 | DnsResourceRecord *rr; |
faa133f3 | 75 | |
74b2466e LP |
76 | if (!s) |
77 | return NULL; | |
78 | ||
46f08bea | 79 | log_debug("Removing scope on link %s, protocol %s, family %s", s->link ? s->link->name : "*", dns_protocol_to_string(s->protocol), s->family == AF_UNSPEC ? "*" : af_to_name(s->family)); |
1716f6dc LP |
80 | |
81 | dns_scope_llmnr_membership(s, false); | |
82 | ||
da0c630e | 83 | while ((t = hashmap_steal_first(s->transactions))) { |
faa133f3 LP |
84 | /* Abort the transaction, but make sure it is not |
85 | * freed while we still look at it */ | |
74b2466e | 86 | |
faa133f3 | 87 | t->block_gc++; |
ec2c5e43 | 88 | dns_transaction_complete(t, DNS_TRANSACTION_ABORTED); |
faa133f3 | 89 | t->block_gc--; |
74b2466e | 90 | |
ec2c5e43 | 91 | dns_transaction_free(t); |
74b2466e LP |
92 | } |
93 | ||
da0c630e LP |
94 | hashmap_free(s->transactions); |
95 | ||
1e43061b | 96 | while ((rr = ordered_hashmap_steal_first(s->conflict_queue))) |
a4076574 LP |
97 | dns_resource_record_unref(rr); |
98 | ||
1e43061b | 99 | ordered_hashmap_free(s->conflict_queue); |
a4076574 LP |
100 | sd_event_source_unref(s->conflict_event_source); |
101 | ||
322345fd | 102 | dns_cache_flush(&s->cache); |
623a4c97 | 103 | dns_zone_flush(&s->zone); |
322345fd | 104 | |
74b2466e LP |
105 | LIST_REMOVE(scopes, s->manager->dns_scopes, s); |
106 | strv_free(s->domains); | |
107 | free(s); | |
108 | ||
109 | return NULL; | |
110 | } | |
111 | ||
2c27fbca | 112 | DnsServer *dns_scope_get_dns_server(DnsScope *s) { |
74b2466e LP |
113 | assert(s); |
114 | ||
1716f6dc LP |
115 | if (s->protocol != DNS_PROTOCOL_DNS) |
116 | return NULL; | |
117 | ||
74b2466e LP |
118 | if (s->link) |
119 | return link_get_dns_server(s->link); | |
120 | else | |
121 | return manager_get_dns_server(s->manager); | |
122 | } | |
123 | ||
124 | void dns_scope_next_dns_server(DnsScope *s) { | |
125 | assert(s); | |
126 | ||
1716f6dc LP |
127 | if (s->protocol != DNS_PROTOCOL_DNS) |
128 | return; | |
129 | ||
74b2466e LP |
130 | if (s->link) |
131 | link_next_dns_server(s->link); | |
132 | else | |
133 | manager_next_dns_server(s->manager); | |
134 | } | |
135 | ||
9df3ba6c TG |
136 | void dns_scope_packet_received(DnsScope *s, usec_t rtt) { |
137 | assert(s); | |
138 | ||
139 | if (rtt > s->max_rtt) { | |
140 | s->max_rtt = rtt; | |
141 | s->resend_timeout = MIN(MAX(MULTICAST_RESEND_TIMEOUT_MIN_USEC, s->max_rtt * 2), | |
142 | MULTICAST_RESEND_TIMEOUT_MAX_USEC); | |
143 | } | |
144 | } | |
145 | ||
146 | void dns_scope_packet_lost(DnsScope *s, usec_t usec) { | |
147 | assert(s); | |
148 | ||
149 | if (s->resend_timeout <= usec) | |
150 | s->resend_timeout = MIN(s->resend_timeout * 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC); | |
151 | } | |
152 | ||
471d40d9 | 153 | int dns_scope_emit(DnsScope *s, int fd, DnsPacket *p) { |
1716f6dc LP |
154 | union in_addr_union addr; |
155 | int ifindex = 0, r; | |
0dd25fb9 | 156 | int family; |
1716f6dc LP |
157 | uint16_t port; |
158 | uint32_t mtu; | |
74b2466e LP |
159 | |
160 | assert(s); | |
161 | assert(p); | |
1716f6dc | 162 | assert(p->protocol == s->protocol); |
471d40d9 | 163 | assert((s->protocol == DNS_PROTOCOL_DNS) != (fd < 0)); |
ad867662 LP |
164 | |
165 | if (s->link) { | |
1716f6dc | 166 | mtu = s->link->mtu; |
74b2466e | 167 | ifindex = s->link->ifindex; |
1716f6dc | 168 | } else |
e1c95994 | 169 | mtu = manager_find_mtu(s->manager); |
74b2466e | 170 | |
106784eb DM |
171 | switch (s->protocol) { |
172 | case DNS_PROTOCOL_DNS: | |
623a4c97 | 173 | if (DNS_PACKET_QDCOUNT(p) > 1) |
15411c0c | 174 | return -EOPNOTSUPP; |
623a4c97 | 175 | |
1716f6dc LP |
176 | if (p->size > DNS_PACKET_UNICAST_SIZE_MAX) |
177 | return -EMSGSIZE; | |
178 | ||
a0166609 | 179 | if (p->size + UDP_PACKET_HEADER_SIZE > mtu) |
1716f6dc LP |
180 | return -EMSGSIZE; |
181 | ||
72290734 TG |
182 | r = manager_write(s->manager, fd, p); |
183 | if (r < 0) | |
184 | return r; | |
185 | ||
106784eb | 186 | break; |
1716f6dc | 187 | |
106784eb | 188 | case DNS_PROTOCOL_LLMNR: |
1716f6dc | 189 | if (DNS_PACKET_QDCOUNT(p) > 1) |
15411c0c | 190 | return -EOPNOTSUPP; |
1716f6dc | 191 | |
aea2429d LP |
192 | if (!ratelimit_test(&s->ratelimit)) |
193 | return -EBUSY; | |
194 | ||
1716f6dc | 195 | family = s->family; |
22a37591 | 196 | port = LLMNR_PORT; |
1716f6dc LP |
197 | |
198 | if (family == AF_INET) { | |
199 | addr.in = LLMNR_MULTICAST_IPV4_ADDRESS; | |
1716f6dc LP |
200 | fd = manager_llmnr_ipv4_udp_fd(s->manager); |
201 | } else if (family == AF_INET6) { | |
202 | addr.in6 = LLMNR_MULTICAST_IPV6_ADDRESS; | |
203 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
1716f6dc LP |
204 | } else |
205 | return -EAFNOSUPPORT; | |
206 | if (fd < 0) | |
207 | return fd; | |
72290734 TG |
208 | |
209 | r = manager_send(s->manager, fd, ifindex, family, &addr, port, p); | |
210 | if (r < 0) | |
211 | return r; | |
106784eb DM |
212 | |
213 | break; | |
214 | ||
215 | default: | |
74b2466e | 216 | return -EAFNOSUPPORT; |
106784eb | 217 | } |
74b2466e | 218 | |
74b2466e LP |
219 | return 1; |
220 | } | |
221 | ||
0db64366 | 222 | static int dns_scope_socket(DnsScope *s, int type, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) { |
8300ba21 | 223 | DnsServer *srv = NULL; |
ad867662 LP |
224 | _cleanup_close_ int fd = -1; |
225 | union sockaddr_union sa = {}; | |
226 | socklen_t salen; | |
623a4c97 LP |
227 | static const int one = 1; |
228 | int ret, r; | |
ad867662 LP |
229 | |
230 | assert(s); | |
623a4c97 | 231 | assert((family == AF_UNSPEC) == !address); |
ad867662 | 232 | |
623a4c97 | 233 | if (family == AF_UNSPEC) { |
2c27fbca | 234 | srv = dns_scope_get_dns_server(s); |
623a4c97 LP |
235 | if (!srv) |
236 | return -ESRCH; | |
237 | ||
238 | sa.sa.sa_family = srv->family; | |
239 | if (srv->family == AF_INET) { | |
240 | sa.in.sin_port = htobe16(port); | |
241 | sa.in.sin_addr = srv->address.in; | |
242 | salen = sizeof(sa.in); | |
243 | } else if (srv->family == AF_INET6) { | |
244 | sa.in6.sin6_port = htobe16(port); | |
245 | sa.in6.sin6_addr = srv->address.in6; | |
246 | sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0; | |
247 | salen = sizeof(sa.in6); | |
248 | } else | |
249 | return -EAFNOSUPPORT; | |
250 | } else { | |
251 | sa.sa.sa_family = family; | |
252 | ||
253 | if (family == AF_INET) { | |
254 | sa.in.sin_port = htobe16(port); | |
255 | sa.in.sin_addr = address->in; | |
256 | salen = sizeof(sa.in); | |
257 | } else if (family == AF_INET6) { | |
258 | sa.in6.sin6_port = htobe16(port); | |
259 | sa.in6.sin6_addr = address->in6; | |
260 | sa.in6.sin6_scope_id = s->link ? s->link->ifindex : 0; | |
261 | salen = sizeof(sa.in6); | |
262 | } else | |
263 | return -EAFNOSUPPORT; | |
264 | } | |
ad867662 | 265 | |
0db64366 | 266 | fd = socket(sa.sa.sa_family, type|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
ad867662 LP |
267 | if (fd < 0) |
268 | return -errno; | |
269 | ||
0db64366 TG |
270 | if (type == SOCK_STREAM) { |
271 | r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)); | |
272 | if (r < 0) | |
273 | return -errno; | |
274 | } | |
623a4c97 LP |
275 | |
276 | if (s->link) { | |
277 | uint32_t ifindex = htobe32(s->link->ifindex); | |
278 | ||
279 | if (sa.sa.sa_family == AF_INET) { | |
280 | r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex)); | |
281 | if (r < 0) | |
282 | return -errno; | |
283 | } else if (sa.sa.sa_family == AF_INET6) { | |
284 | r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex)); | |
285 | if (r < 0) | |
286 | return -errno; | |
287 | } | |
288 | } | |
289 | ||
290 | if (s->protocol == DNS_PROTOCOL_LLMNR) { | |
bf3f1271 | 291 | /* RFC 4795, section 2.5 requires the TTL to be set to 1 */ |
623a4c97 LP |
292 | |
293 | if (sa.sa.sa_family == AF_INET) { | |
294 | r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); | |
295 | if (r < 0) | |
296 | return -errno; | |
297 | } else if (sa.sa.sa_family == AF_INET6) { | |
298 | r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); | |
299 | if (r < 0) | |
300 | return -errno; | |
301 | } | |
302 | } | |
ad867662 LP |
303 | |
304 | r = connect(fd, &sa.sa, salen); | |
305 | if (r < 0 && errno != EINPROGRESS) | |
306 | return -errno; | |
307 | ||
8300ba21 TG |
308 | if (server) |
309 | *server = srv; | |
310 | ||
ad867662 LP |
311 | ret = fd; |
312 | fd = -1; | |
623a4c97 | 313 | |
ad867662 LP |
314 | return ret; |
315 | } | |
316 | ||
0db64366 TG |
317 | int dns_scope_udp_dns_socket(DnsScope *s, DnsServer **server) { |
318 | return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, 53, server); | |
319 | } | |
320 | ||
321 | int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) { | |
322 | return dns_scope_socket(s, SOCK_STREAM, family, address, port, server); | |
323 | } | |
324 | ||
51323288 | 325 | DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, const char *domain) { |
74b2466e LP |
326 | char **i; |
327 | ||
328 | assert(s); | |
329 | assert(domain); | |
330 | ||
51323288 LP |
331 | if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex)) |
332 | return DNS_SCOPE_NO; | |
333 | ||
334 | if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family) & flags) == 0) | |
335 | return DNS_SCOPE_NO; | |
336 | ||
faa133f3 | 337 | if (dns_name_root(domain) != 0) |
74b2466e LP |
338 | return DNS_SCOPE_NO; |
339 | ||
78c6a153 LP |
340 | /* Never resolve any loopback hostname or IP address via DNS, |
341 | * LLMNR or mDNS. Instead, always rely on synthesized RRs for | |
342 | * these. */ | |
343 | if (is_localhost(domain) || | |
344 | dns_name_endswith(domain, "127.in-addr.arpa") > 0 || | |
9436e8ca LP |
345 | dns_name_equal(domain, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0) |
346 | return DNS_SCOPE_NO; | |
347 | ||
9b644bf9 LP |
348 | STRV_FOREACH(i, s->domains) |
349 | if (dns_name_endswith(domain, *i) > 0) | |
350 | return DNS_SCOPE_YES; | |
351 | ||
106784eb DM |
352 | switch (s->protocol) { |
353 | case DNS_PROTOCOL_DNS: | |
faa133f3 LP |
354 | if (dns_name_endswith(domain, "254.169.in-addr.arpa") == 0 && |
355 | dns_name_endswith(domain, "0.8.e.f.ip6.arpa") == 0 && | |
356 | dns_name_single_label(domain) == 0) | |
357 | return DNS_SCOPE_MAYBE; | |
1716f6dc | 358 | |
faa133f3 | 359 | return DNS_SCOPE_NO; |
1716f6dc | 360 | |
106784eb | 361 | case DNS_PROTOCOL_MDNS: |
78c6a153 LP |
362 | if ((s->family == AF_INET && dns_name_endswith(domain, "in-addr.arpa") > 0) || |
363 | (s->family == AF_INET6 && dns_name_endswith(domain, "ip6.arpa") > 0) || | |
364 | (dns_name_endswith(domain, "local") > 0 && /* only resolve names ending in .local via mDNS */ | |
365 | dns_name_equal(domain, "local") == 0 && /* but not the single-label "local" name itself */ | |
366 | manager_is_own_hostname(s->manager, domain) <= 0)) /* never resolve the local hostname via mDNS */ | |
d8b7e75f | 367 | return DNS_SCOPE_MAYBE; |
74b2466e LP |
368 | |
369 | return DNS_SCOPE_NO; | |
74b2466e | 370 | |
106784eb | 371 | case DNS_PROTOCOL_LLMNR: |
78c6a153 LP |
372 | if ((s->family == AF_INET && dns_name_endswith(domain, "in-addr.arpa") > 0) || |
373 | (s->family == AF_INET6 && dns_name_endswith(domain, "ip6.arpa") > 0) || | |
374 | (dns_name_single_label(domain) > 0 && /* only resolve single label names via LLMNR */ | |
375 | !is_gateway_hostname(domain) && /* don't resolve "gateway" with LLMNR, let nss-myhostname handle this */ | |
376 | manager_is_own_hostname(s->manager, domain) <= 0)) /* never resolve the local hostname via LLMNR */ | |
1716f6dc | 377 | return DNS_SCOPE_MAYBE; |
74b2466e | 378 | |
1716f6dc | 379 | return DNS_SCOPE_NO; |
74b2466e | 380 | |
106784eb DM |
381 | default: |
382 | assert_not_reached("Unknown scope protocol"); | |
383 | } | |
1716f6dc LP |
384 | } |
385 | ||
386 | int dns_scope_good_key(DnsScope *s, DnsResourceKey *key) { | |
387 | assert(s); | |
388 | assert(key); | |
389 | ||
390 | if (s->protocol == DNS_PROTOCOL_DNS) | |
391 | return true; | |
392 | ||
393 | /* On mDNS and LLMNR, send A and AAAA queries only on the | |
394 | * respective scopes */ | |
395 | ||
396 | if (s->family == AF_INET && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_AAAA) | |
397 | return false; | |
398 | ||
399 | if (s->family == AF_INET6 && key->class == DNS_CLASS_IN && key->type == DNS_TYPE_A) | |
400 | return false; | |
401 | ||
402 | return true; | |
403 | } | |
404 | ||
405 | int dns_scope_llmnr_membership(DnsScope *s, bool b) { | |
406 | int fd; | |
407 | ||
5ba73e9b | 408 | assert(s); |
4de120ee LP |
409 | |
410 | if (s->protocol != DNS_PROTOCOL_LLMNR) | |
411 | return 0; | |
412 | ||
5ba73e9b LP |
413 | assert(s->link); |
414 | ||
1716f6dc LP |
415 | if (s->family == AF_INET) { |
416 | struct ip_mreqn mreqn = { | |
417 | .imr_multiaddr = LLMNR_MULTICAST_IPV4_ADDRESS, | |
418 | .imr_ifindex = s->link->ifindex, | |
419 | }; | |
420 | ||
421 | fd = manager_llmnr_ipv4_udp_fd(s->manager); | |
422 | if (fd < 0) | |
423 | return fd; | |
424 | ||
7b4c2ee7 LP |
425 | /* Always first try to drop membership before we add |
426 | * one. This is necessary on some devices, such as | |
427 | * veth. */ | |
428 | if (b) | |
dc751688 | 429 | (void) setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)); |
7b4c2ee7 | 430 | |
1716f6dc LP |
431 | if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0) |
432 | return -errno; | |
433 | ||
434 | } else if (s->family == AF_INET6) { | |
435 | struct ipv6_mreq mreq = { | |
436 | .ipv6mr_multiaddr = LLMNR_MULTICAST_IPV6_ADDRESS, | |
437 | .ipv6mr_interface = s->link->ifindex, | |
438 | }; | |
439 | ||
440 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
441 | if (fd < 0) | |
442 | return fd; | |
443 | ||
7b4c2ee7 | 444 | if (b) |
dc751688 | 445 | (void) setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); |
7b4c2ee7 | 446 | |
1716f6dc LP |
447 | if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) |
448 | return -errno; | |
449 | } else | |
450 | return -EAFNOSUPPORT; | |
451 | ||
452 | return 0; | |
74b2466e | 453 | } |
623a4c97 | 454 | |
ec2c5e43 LP |
455 | static int dns_scope_make_reply_packet( |
456 | DnsScope *s, | |
457 | uint16_t id, | |
458 | int rcode, | |
459 | DnsQuestion *q, | |
460 | DnsAnswer *answer, | |
461 | DnsAnswer *soa, | |
462 | bool tentative, | |
463 | DnsPacket **ret) { | |
464 | ||
623a4c97 LP |
465 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
466 | unsigned i; | |
467 | int r; | |
468 | ||
469 | assert(s); | |
a4076574 | 470 | assert(ret); |
623a4c97 | 471 | |
75cd513e TA |
472 | if ((!q || q->n_keys <= 0) |
473 | && (!answer || answer->n_rrs <= 0) | |
474 | && (!soa || soa->n_rrs <= 0)) | |
623a4c97 LP |
475 | return -EINVAL; |
476 | ||
477 | r = dns_packet_new(&p, s->protocol, 0); | |
478 | if (r < 0) | |
479 | return r; | |
480 | ||
481 | DNS_PACKET_HEADER(p)->id = id; | |
ea917db9 LP |
482 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( |
483 | 1 /* qr */, | |
484 | 0 /* opcode */, | |
485 | 0 /* c */, | |
486 | 0 /* tc */, | |
ec2c5e43 | 487 | tentative, |
ea917db9 LP |
488 | 0 /* (ra) */, |
489 | 0 /* (ad) */, | |
490 | 0 /* (cd) */, | |
491 | rcode)); | |
623a4c97 LP |
492 | |
493 | if (q) { | |
494 | for (i = 0; i < q->n_keys; i++) { | |
495 | r = dns_packet_append_key(p, q->keys[i], NULL); | |
496 | if (r < 0) | |
497 | return r; | |
498 | } | |
499 | ||
500 | DNS_PACKET_HEADER(p)->qdcount = htobe16(q->n_keys); | |
501 | } | |
502 | ||
8bf52d3d LP |
503 | if (answer) { |
504 | for (i = 0; i < answer->n_rrs; i++) { | |
78c6a153 | 505 | r = dns_packet_append_rr(p, answer->items[i].rr, NULL); |
623a4c97 LP |
506 | if (r < 0) |
507 | return r; | |
508 | } | |
509 | ||
8bf52d3d LP |
510 | DNS_PACKET_HEADER(p)->ancount = htobe16(answer->n_rrs); |
511 | } | |
512 | ||
513 | if (soa) { | |
514 | for (i = 0; i < soa->n_rrs; i++) { | |
78c6a153 | 515 | r = dns_packet_append_rr(p, soa->items[i].rr, NULL); |
8bf52d3d LP |
516 | if (r < 0) |
517 | return r; | |
518 | } | |
519 | ||
520 | DNS_PACKET_HEADER(p)->arcount = htobe16(soa->n_rrs); | |
623a4c97 LP |
521 | } |
522 | ||
523 | *ret = p; | |
524 | p = NULL; | |
525 | ||
526 | return 0; | |
527 | } | |
528 | ||
a4076574 LP |
529 | static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) { |
530 | unsigned n; | |
531 | ||
532 | assert(s); | |
533 | assert(p); | |
534 | ||
535 | if (p->question) | |
536 | for (n = 0; n < p->question->n_keys; n++) | |
537 | dns_zone_verify_conflicts(&s->zone, p->question->keys[n]); | |
538 | if (p->answer) | |
539 | for (n = 0; n < p->answer->n_rrs; n++) | |
78c6a153 | 540 | dns_zone_verify_conflicts(&s->zone, p->answer->items[n].rr->key); |
a4076574 LP |
541 | } |
542 | ||
623a4c97 LP |
543 | void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { |
544 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; | |
8bf52d3d | 545 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL; |
5032b16d | 546 | DnsResourceKey *key = NULL; |
ec2c5e43 | 547 | bool tentative = false; |
623a4c97 LP |
548 | int r, fd; |
549 | ||
550 | assert(s); | |
551 | assert(p); | |
552 | ||
553 | if (p->protocol != DNS_PROTOCOL_LLMNR) | |
554 | return; | |
555 | ||
2442b93d LP |
556 | if (p->ipproto == IPPROTO_UDP) { |
557 | /* Don't accept UDP queries directed to anything but | |
558 | * the LLMNR multicast addresses. See RFC 4795, | |
d076c6f9 | 559 | * section 2.5. */ |
2442b93d LP |
560 | |
561 | if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS)) | |
562 | return; | |
563 | ||
564 | if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS)) | |
565 | return; | |
566 | } | |
567 | ||
623a4c97 LP |
568 | r = dns_packet_extract(p); |
569 | if (r < 0) { | |
da927ba9 | 570 | log_debug_errno(r, "Failed to extract resources from incoming packet: %m"); |
623a4c97 LP |
571 | return; |
572 | } | |
573 | ||
8b757a38 | 574 | if (DNS_PACKET_LLMNR_C(p)) { |
a4076574 LP |
575 | /* Somebody notified us about a possible conflict */ |
576 | dns_scope_verify_conflicts(s, p); | |
ea917db9 LP |
577 | return; |
578 | } | |
579 | ||
5032b16d LP |
580 | assert(p->question->n_keys == 1); |
581 | key = p->question->keys[0]; | |
582 | ||
583 | r = dns_zone_lookup(&s->zone, key, &answer, &soa, &tentative); | |
623a4c97 | 584 | if (r < 0) { |
da927ba9 | 585 | log_debug_errno(r, "Failed to lookup key: %m"); |
623a4c97 LP |
586 | return; |
587 | } | |
588 | if (r == 0) | |
589 | return; | |
590 | ||
fcf57f9c LP |
591 | if (answer) |
592 | dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0); | |
af93291c | 593 | |
ec2c5e43 | 594 | r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply); |
623a4c97 | 595 | if (r < 0) { |
da927ba9 | 596 | log_debug_errno(r, "Failed to build reply packet: %m"); |
623a4c97 LP |
597 | return; |
598 | } | |
599 | ||
600 | if (stream) | |
601 | r = dns_stream_write_packet(stream, reply); | |
602 | else { | |
aea2429d LP |
603 | if (!ratelimit_test(&s->ratelimit)) |
604 | return; | |
605 | ||
623a4c97 LP |
606 | if (p->family == AF_INET) |
607 | fd = manager_llmnr_ipv4_udp_fd(s->manager); | |
608 | else if (p->family == AF_INET6) | |
609 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
610 | else { | |
611 | log_debug("Unknown protocol"); | |
612 | return; | |
613 | } | |
614 | if (fd < 0) { | |
da927ba9 | 615 | log_debug_errno(fd, "Failed to get reply socket: %m"); |
623a4c97 LP |
616 | return; |
617 | } | |
618 | ||
6e068472 LP |
619 | /* Note that we always immediately reply to all LLMNR |
620 | * requests, and do not wait any time, since we | |
621 | * verified uniqueness for all records. Also see RFC | |
622 | * 4795, Section 2.7 */ | |
623 | ||
623a4c97 LP |
624 | r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, reply); |
625 | } | |
626 | ||
627 | if (r < 0) { | |
da927ba9 | 628 | log_debug_errno(r, "Failed to send reply packet: %m"); |
623a4c97 LP |
629 | return; |
630 | } | |
631 | } | |
ec2c5e43 | 632 | |
f52e61da | 633 | DnsTransaction *dns_scope_find_transaction(DnsScope *scope, DnsResourceKey *key, bool cache_ok) { |
ec2c5e43 LP |
634 | DnsTransaction *t; |
635 | ||
636 | assert(scope); | |
f52e61da | 637 | assert(key); |
ec2c5e43 | 638 | |
da0c630e LP |
639 | /* Try to find an ongoing transaction that is a equal to the |
640 | * specified question */ | |
641 | t = hashmap_get(scope->transactions, key); | |
642 | if (!t) | |
643 | return NULL; | |
dc4d47e2 | 644 | |
da0c630e LP |
645 | /* Refuse reusing transactions that completed based on cached |
646 | * data instead of a real packet, if that's requested. */ | |
647 | if (!cache_ok && | |
648 | IN_SET(t->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE) && | |
649 | !t->received) | |
650 | return NULL; | |
ec2c5e43 | 651 | |
da0c630e | 652 | return t; |
ec2c5e43 | 653 | } |
a4076574 LP |
654 | |
655 | static int dns_scope_make_conflict_packet( | |
656 | DnsScope *s, | |
657 | DnsResourceRecord *rr, | |
658 | DnsPacket **ret) { | |
659 | ||
660 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
661 | int r; | |
662 | ||
663 | assert(s); | |
664 | assert(rr); | |
665 | assert(ret); | |
666 | ||
667 | r = dns_packet_new(&p, s->protocol, 0); | |
668 | if (r < 0) | |
669 | return r; | |
670 | ||
671 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( | |
672 | 0 /* qr */, | |
673 | 0 /* opcode */, | |
674 | 1 /* conflict */, | |
675 | 0 /* tc */, | |
676 | 0 /* t */, | |
677 | 0 /* (ra) */, | |
678 | 0 /* (ad) */, | |
679 | 0 /* (cd) */, | |
680 | 0)); | |
681 | random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t)); | |
682 | DNS_PACKET_HEADER(p)->qdcount = htobe16(1); | |
683 | DNS_PACKET_HEADER(p)->arcount = htobe16(1); | |
684 | ||
685 | r = dns_packet_append_key(p, rr->key, NULL); | |
686 | if (r < 0) | |
687 | return r; | |
688 | ||
689 | r = dns_packet_append_rr(p, rr, NULL); | |
690 | if (r < 0) | |
691 | return r; | |
692 | ||
693 | *ret = p; | |
694 | p = NULL; | |
695 | ||
696 | return 0; | |
697 | } | |
698 | ||
699 | static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata) { | |
700 | DnsScope *scope = userdata; | |
701 | int r; | |
702 | ||
703 | assert(es); | |
704 | assert(scope); | |
705 | ||
706 | scope->conflict_event_source = sd_event_source_unref(scope->conflict_event_source); | |
707 | ||
708 | for (;;) { | |
709 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; | |
710 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
711 | ||
1e43061b | 712 | rr = ordered_hashmap_steal_first(scope->conflict_queue); |
a4076574 LP |
713 | if (!rr) |
714 | break; | |
715 | ||
716 | r = dns_scope_make_conflict_packet(scope, rr, &p); | |
717 | if (r < 0) { | |
da927ba9 | 718 | log_error_errno(r, "Failed to make conflict packet: %m"); |
a4076574 LP |
719 | return 0; |
720 | } | |
721 | ||
471d40d9 | 722 | r = dns_scope_emit(scope, -1, p); |
a4076574 | 723 | if (r < 0) |
da927ba9 | 724 | log_debug_errno(r, "Failed to send conflict packet: %m"); |
a4076574 LP |
725 | } |
726 | ||
727 | return 0; | |
728 | } | |
729 | ||
730 | int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) { | |
731 | usec_t jitter; | |
732 | int r; | |
733 | ||
734 | assert(scope); | |
735 | assert(rr); | |
736 | ||
737 | /* We don't send these queries immediately. Instead, we queue | |
738 | * them, and send them after some jitter delay. */ | |
1e43061b | 739 | r = ordered_hashmap_ensure_allocated(&scope->conflict_queue, &dns_resource_key_hash_ops); |
a4076574 LP |
740 | if (r < 0) { |
741 | log_oom(); | |
742 | return r; | |
743 | } | |
744 | ||
745 | /* We only place one RR per key in the conflict | |
746 | * messages, not all of them. That should be enough to | |
747 | * indicate where there might be a conflict */ | |
1e43061b | 748 | r = ordered_hashmap_put(scope->conflict_queue, rr->key, rr); |
a4076574 LP |
749 | if (r == -EEXIST || r == 0) |
750 | return 0; | |
f647962d MS |
751 | if (r < 0) |
752 | return log_debug_errno(r, "Failed to queue conflicting RR: %m"); | |
a4076574 LP |
753 | |
754 | dns_resource_record_ref(rr); | |
755 | ||
756 | if (scope->conflict_event_source) | |
757 | return 0; | |
758 | ||
759 | random_bytes(&jitter, sizeof(jitter)); | |
760 | jitter %= LLMNR_JITTER_INTERVAL_USEC; | |
761 | ||
762 | r = sd_event_add_time(scope->manager->event, | |
763 | &scope->conflict_event_source, | |
764 | clock_boottime_or_monotonic(), | |
765 | now(clock_boottime_or_monotonic()) + jitter, | |
766 | LLMNR_JITTER_INTERVAL_USEC, | |
767 | on_conflict_dispatch, scope); | |
f647962d MS |
768 | if (r < 0) |
769 | return log_debug_errno(r, "Failed to add conflict dispatch event: %m"); | |
a4076574 LP |
770 | |
771 | return 0; | |
772 | } | |
773 | ||
774 | void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p) { | |
775 | unsigned i; | |
776 | int r; | |
777 | ||
778 | assert(scope); | |
779 | assert(p); | |
780 | ||
781 | if (p->protocol != DNS_PROTOCOL_LLMNR) | |
782 | return; | |
783 | ||
784 | if (DNS_PACKET_RRCOUNT(p) <= 0) | |
785 | return; | |
786 | ||
8b757a38 | 787 | if (DNS_PACKET_LLMNR_C(p) != 0) |
a4076574 LP |
788 | return; |
789 | ||
8b757a38 | 790 | if (DNS_PACKET_LLMNR_T(p) != 0) |
a4076574 LP |
791 | return; |
792 | ||
793 | if (manager_our_packet(scope->manager, p)) | |
794 | return; | |
795 | ||
796 | r = dns_packet_extract(p); | |
797 | if (r < 0) { | |
da927ba9 | 798 | log_debug_errno(r, "Failed to extract packet: %m"); |
a4076574 LP |
799 | return; |
800 | } | |
801 | ||
802 | log_debug("Checking for conflicts..."); | |
803 | ||
804 | for (i = 0; i < p->answer->n_rrs; i++) { | |
805 | ||
806 | /* Check for conflicts against the local zone. If we | |
807 | * found one, we won't check any further */ | |
78c6a153 | 808 | r = dns_zone_check_conflicts(&scope->zone, p->answer->items[i].rr); |
a4076574 LP |
809 | if (r != 0) |
810 | continue; | |
811 | ||
812 | /* Check for conflicts against the local cache. If so, | |
813 | * send out an advisory query, to inform everybody */ | |
78c6a153 | 814 | r = dns_cache_check_conflicts(&scope->cache, p->answer->items[i].rr, p->family, &p->sender); |
a4076574 LP |
815 | if (r <= 0) |
816 | continue; | |
817 | ||
78c6a153 | 818 | dns_scope_notify_conflict(scope, p->answer->items[i].rr); |
a4076574 LP |
819 | } |
820 | } | |
4d506d6b LP |
821 | |
822 | void dns_scope_dump(DnsScope *s, FILE *f) { | |
823 | assert(s); | |
824 | ||
825 | if (!f) | |
826 | f = stdout; | |
827 | ||
828 | fputs("[Scope protocol=", f); | |
829 | fputs(dns_protocol_to_string(s->protocol), f); | |
830 | ||
831 | if (s->link) { | |
832 | fputs(" interface=", f); | |
833 | fputs(s->link->name, f); | |
834 | } | |
835 | ||
836 | if (s->family != AF_UNSPEC) { | |
837 | fputs(" family=", f); | |
838 | fputs(af_to_name(s->family), f); | |
839 | } | |
840 | ||
841 | fputs("]\n", f); | |
842 | ||
843 | if (!dns_zone_is_empty(&s->zone)) { | |
844 | fputs("ZONE:\n", f); | |
845 | dns_zone_dump(&s->zone, f); | |
846 | } | |
847 | ||
848 | if (!dns_cache_is_empty(&s->cache)) { | |
849 | fputs("CACHE:\n", f); | |
850 | dns_cache_dump(&s->cache, f); | |
851 | } | |
852 | } |