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Commit | Line | Data |
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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
74b2466e | 2 | |
ad867662 LP |
3 | #include <netinet/tcp.h> |
4 | ||
46f08bea | 5 | #include "af-list.h" |
b5efdb8a | 6 | #include "alloc-util.h" |
4ad7f276 | 7 | #include "dns-domain.h" |
d79677ab | 8 | #include "errno-util.h" |
3ffd4af2 LP |
9 | #include "fd-util.h" |
10 | #include "hostname-util.h" | |
f5947a5e | 11 | #include "missing_network.h" |
3ffd4af2 | 12 | #include "random-util.h" |
6db6a464 | 13 | #include "resolved-dnssd.h" |
74b2466e | 14 | #include "resolved-dns-scope.h" |
a2bf8a19 | 15 | #include "resolved-dns-zone.h" |
3ffd4af2 | 16 | #include "resolved-llmnr.h" |
b4f1862d | 17 | #include "resolved-mdns.h" |
3ffd4af2 LP |
18 | #include "socket-util.h" |
19 | #include "strv.h" | |
74b2466e | 20 | |
aea2429d LP |
21 | #define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC) |
22 | #define MULTICAST_RATELIMIT_BURST 1000 | |
23 | ||
9df3ba6c TG |
24 | /* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */ |
25 | #define MULTICAST_RESEND_TIMEOUT_MIN_USEC (100 * USEC_PER_MSEC) | |
26 | #define MULTICAST_RESEND_TIMEOUT_MAX_USEC (1 * USEC_PER_SEC) | |
27 | ||
0dd25fb9 | 28 | int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int family) { |
74b2466e LP |
29 | DnsScope *s; |
30 | ||
31 | assert(m); | |
32 | assert(ret); | |
33 | ||
9a1bbc66 | 34 | s = new(DnsScope, 1); |
74b2466e LP |
35 | if (!s) |
36 | return -ENOMEM; | |
37 | ||
9a1bbc66 LP |
38 | *s = (DnsScope) { |
39 | .manager = m, | |
40 | .link = l, | |
41 | .protocol = protocol, | |
42 | .family = family, | |
43 | .resend_timeout = MULTICAST_RESEND_TIMEOUT_MIN_USEC, | |
44 | }; | |
74b2466e | 45 | |
ad6c0475 LP |
46 | if (protocol == DNS_PROTOCOL_DNS) { |
47 | /* Copy DNSSEC mode from the link if it is set there, | |
48 | * otherwise take the manager's DNSSEC mode. Note that | |
49 | * we copy this only at scope creation time, and do | |
50 | * not update it from the on, even if the setting | |
51 | * changes. */ | |
52 | ||
d050561a | 53 | if (l) { |
c69fa7e3 | 54 | s->dnssec_mode = link_get_dnssec_mode(l); |
c9299be2 | 55 | s->dns_over_tls_mode = link_get_dns_over_tls_mode(l); |
d050561a | 56 | } else { |
c69fa7e3 | 57 | s->dnssec_mode = manager_get_dnssec_mode(m); |
c9299be2 | 58 | s->dns_over_tls_mode = manager_get_dns_over_tls_mode(m); |
d050561a | 59 | } |
5d67a7ae | 60 | |
5d67a7ae | 61 | } else { |
658f7f02 | 62 | s->dnssec_mode = DNSSEC_NO; |
c9299be2 | 63 | s->dns_over_tls_mode = DNS_OVER_TLS_NO; |
5d67a7ae | 64 | } |
ad6c0475 | 65 | |
74b2466e LP |
66 | LIST_PREPEND(scopes, m->dns_scopes, s); |
67 | ||
1716f6dc | 68 | dns_scope_llmnr_membership(s, true); |
0db4c90a | 69 | dns_scope_mdns_membership(s, true); |
1716f6dc | 70 | |
6ff79f76 | 71 | log_debug("New scope on link %s, protocol %s, family %s", l ? l->ifname : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family)); |
1716f6dc | 72 | |
aea2429d | 73 | /* Enforce ratelimiting for the multicast protocols */ |
8c227e7f | 74 | s->ratelimit = (RateLimit) { MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST }; |
aea2429d | 75 | |
74b2466e LP |
76 | *ret = s; |
77 | return 0; | |
78 | } | |
79 | ||
801ad6a6 | 80 | static void dns_scope_abort_transactions(DnsScope *s) { |
801ad6a6 | 81 | assert(s); |
1716f6dc | 82 | |
f9ebb22a LP |
83 | while (s->transactions) { |
84 | DnsTransaction *t = s->transactions; | |
85 | ||
faa133f3 LP |
86 | /* Abort the transaction, but make sure it is not |
87 | * freed while we still look at it */ | |
74b2466e | 88 | |
faa133f3 | 89 | t->block_gc++; |
f4e38037 LP |
90 | if (DNS_TRANSACTION_IS_LIVE(t->state)) |
91 | dns_transaction_complete(t, DNS_TRANSACTION_ABORTED); | |
faa133f3 | 92 | t->block_gc--; |
74b2466e | 93 | |
ec2c5e43 | 94 | dns_transaction_free(t); |
74b2466e | 95 | } |
801ad6a6 LP |
96 | } |
97 | ||
98 | DnsScope* dns_scope_free(DnsScope *s) { | |
801ad6a6 LP |
99 | if (!s) |
100 | return NULL; | |
101 | ||
6ff79f76 | 102 | log_debug("Removing scope on link %s, protocol %s, family %s", s->link ? s->link->ifname : "*", dns_protocol_to_string(s->protocol), s->family == AF_UNSPEC ? "*" : af_to_name(s->family)); |
801ad6a6 LP |
103 | |
104 | dns_scope_llmnr_membership(s, false); | |
0db4c90a | 105 | dns_scope_mdns_membership(s, false); |
801ad6a6 LP |
106 | dns_scope_abort_transactions(s); |
107 | ||
108 | while (s->query_candidates) | |
0e0fd08f | 109 | dns_query_candidate_unref(s->query_candidates); |
74b2466e | 110 | |
f9ebb22a | 111 | hashmap_free(s->transactions_by_key); |
da0c630e | 112 | |
224b0e7a | 113 | ordered_hashmap_free_with_destructor(s->conflict_queue, dns_resource_record_unref); |
97935302 | 114 | sd_event_source_disable_unref(s->conflict_event_source); |
a4076574 | 115 | |
97935302 | 116 | sd_event_source_disable_unref(s->announce_event_source); |
53fda2bb | 117 | |
322345fd | 118 | dns_cache_flush(&s->cache); |
623a4c97 | 119 | dns_zone_flush(&s->zone); |
322345fd | 120 | |
74b2466e | 121 | LIST_REMOVE(scopes, s->manager->dns_scopes, s); |
6b430fdb | 122 | return mfree(s); |
74b2466e LP |
123 | } |
124 | ||
2c27fbca | 125 | DnsServer *dns_scope_get_dns_server(DnsScope *s) { |
74b2466e LP |
126 | assert(s); |
127 | ||
1716f6dc LP |
128 | if (s->protocol != DNS_PROTOCOL_DNS) |
129 | return NULL; | |
130 | ||
74b2466e LP |
131 | if (s->link) |
132 | return link_get_dns_server(s->link); | |
133 | else | |
134 | return manager_get_dns_server(s->manager); | |
135 | } | |
136 | ||
44db02d0 LP |
137 | unsigned dns_scope_get_n_dns_servers(DnsScope *s) { |
138 | unsigned n = 0; | |
139 | DnsServer *i; | |
140 | ||
141 | assert(s); | |
142 | ||
143 | if (s->protocol != DNS_PROTOCOL_DNS) | |
144 | return 0; | |
145 | ||
146 | if (s->link) | |
147 | i = s->link->dns_servers; | |
148 | else | |
149 | i = s->manager->dns_servers; | |
150 | ||
151 | for (; i; i = i->servers_next) | |
152 | n++; | |
153 | ||
154 | return n; | |
155 | } | |
156 | ||
5e8bc852 | 157 | void dns_scope_next_dns_server(DnsScope *s, DnsServer *if_current) { |
74b2466e LP |
158 | assert(s); |
159 | ||
1716f6dc LP |
160 | if (s->protocol != DNS_PROTOCOL_DNS) |
161 | return; | |
162 | ||
5e8bc852 LP |
163 | /* Changes to the next DNS server in the list. If 'if_current' is passed will do so only if the |
164 | * current DNS server still matches it. */ | |
165 | ||
74b2466e | 166 | if (s->link) |
5e8bc852 | 167 | link_next_dns_server(s->link, if_current); |
74b2466e | 168 | else |
5e8bc852 | 169 | manager_next_dns_server(s->manager, if_current); |
74b2466e LP |
170 | } |
171 | ||
9df3ba6c TG |
172 | void dns_scope_packet_received(DnsScope *s, usec_t rtt) { |
173 | assert(s); | |
174 | ||
84129d46 LP |
175 | if (rtt <= s->max_rtt) |
176 | return; | |
177 | ||
178 | s->max_rtt = rtt; | |
179 | s->resend_timeout = MIN(MAX(MULTICAST_RESEND_TIMEOUT_MIN_USEC, s->max_rtt * 2), MULTICAST_RESEND_TIMEOUT_MAX_USEC); | |
9df3ba6c TG |
180 | } |
181 | ||
182 | void dns_scope_packet_lost(DnsScope *s, usec_t usec) { | |
183 | assert(s); | |
184 | ||
185 | if (s->resend_timeout <= usec) | |
186 | s->resend_timeout = MIN(s->resend_timeout * 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC); | |
187 | } | |
188 | ||
d79677ab LP |
189 | static int dns_scope_emit_one(DnsScope *s, int fd, int family, DnsPacket *p) { |
190 | int r; | |
74b2466e LP |
191 | |
192 | assert(s); | |
193 | assert(p); | |
1716f6dc | 194 | assert(p->protocol == s->protocol); |
ad867662 | 195 | |
d79677ab LP |
196 | if (family == AF_UNSPEC) { |
197 | if (s->family == AF_UNSPEC) | |
198 | return -EAFNOSUPPORT; | |
199 | ||
200 | family = s->family; | |
201 | } | |
74b2466e | 202 | |
106784eb | 203 | switch (s->protocol) { |
519ef046 | 204 | |
d79677ab LP |
205 | case DNS_PROTOCOL_DNS: { |
206 | size_t mtu, udp_size, min_mtu, socket_mtu = 0; | |
207 | ||
519ef046 | 208 | assert(fd >= 0); |
9c5e12a4 | 209 | |
d79677ab | 210 | if (DNS_PACKET_QDCOUNT(p) > 1) /* Classic DNS only allows one question per packet */ |
15411c0c | 211 | return -EOPNOTSUPP; |
623a4c97 | 212 | |
1716f6dc LP |
213 | if (p->size > DNS_PACKET_UNICAST_SIZE_MAX) |
214 | return -EMSGSIZE; | |
215 | ||
d79677ab LP |
216 | /* Determine the local most accurate MTU */ |
217 | if (s->link) | |
218 | mtu = s->link->mtu; | |
219 | else | |
220 | mtu = manager_find_mtu(s->manager); | |
221 | ||
222 | /* Acquire the socket's PMDU MTU */ | |
223 | r = socket_get_mtu(fd, family, &socket_mtu); | |
224 | if (r < 0 && !ERRNO_IS_DISCONNECT(r)) /* Will return ENOTCONN if no information is available yet */ | |
225 | return log_debug_errno(r, "Failed to read socket MTU: %m"); | |
226 | ||
227 | /* Determine the appropriate UDP header size */ | |
228 | udp_size = udp_header_size(family); | |
229 | min_mtu = udp_size + DNS_PACKET_HEADER_SIZE; | |
230 | ||
231 | log_debug("Emitting UDP, link MTU is %zu, socket MTU is %zu, minimal MTU is %zu", | |
232 | mtu, socket_mtu, min_mtu); | |
233 | ||
234 | /* Clamp by the kernel's idea of the (path) MTU */ | |
235 | if (socket_mtu != 0 && socket_mtu < mtu) | |
236 | mtu = socket_mtu; | |
237 | ||
238 | /* Put a lower limit, in case all MTU data we acquired was rubbish */ | |
239 | if (mtu < min_mtu) | |
240 | mtu = min_mtu; | |
241 | ||
242 | /* Now check our packet size against the MTU we determined */ | |
243 | if (udp_size + p->size > mtu) | |
244 | return -EMSGSIZE; /* This means: try TCP instead */ | |
1716f6dc | 245 | |
72290734 TG |
246 | r = manager_write(s->manager, fd, p); |
247 | if (r < 0) | |
248 | return r; | |
249 | ||
106784eb | 250 | break; |
d79677ab LP |
251 | } |
252 | ||
253 | case DNS_PROTOCOL_LLMNR: { | |
254 | union in_addr_union addr; | |
1716f6dc | 255 | |
519ef046 LP |
256 | assert(fd < 0); |
257 | ||
1716f6dc | 258 | if (DNS_PACKET_QDCOUNT(p) > 1) |
15411c0c | 259 | return -EOPNOTSUPP; |
1716f6dc | 260 | |
7994ac1d | 261 | if (!ratelimit_below(&s->ratelimit)) |
aea2429d LP |
262 | return -EBUSY; |
263 | ||
1716f6dc LP |
264 | if (family == AF_INET) { |
265 | addr.in = LLMNR_MULTICAST_IPV4_ADDRESS; | |
1716f6dc LP |
266 | fd = manager_llmnr_ipv4_udp_fd(s->manager); |
267 | } else if (family == AF_INET6) { | |
268 | addr.in6 = LLMNR_MULTICAST_IPV6_ADDRESS; | |
269 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
1716f6dc LP |
270 | } else |
271 | return -EAFNOSUPPORT; | |
272 | if (fd < 0) | |
273 | return fd; | |
72290734 | 274 | |
d79677ab | 275 | r = manager_send(s->manager, fd, s->link->ifindex, family, &addr, LLMNR_PORT, NULL, p); |
b4f1862d DM |
276 | if (r < 0) |
277 | return r; | |
278 | ||
279 | break; | |
d79677ab | 280 | } |
b4f1862d | 281 | |
d79677ab LP |
282 | case DNS_PROTOCOL_MDNS: { |
283 | union in_addr_union addr; | |
519ef046 LP |
284 | assert(fd < 0); |
285 | ||
7994ac1d | 286 | if (!ratelimit_below(&s->ratelimit)) |
b4f1862d DM |
287 | return -EBUSY; |
288 | ||
b4f1862d | 289 | if (family == AF_INET) { |
84b0ff0e SB |
290 | if (in4_addr_is_null(&p->destination.in)) |
291 | addr.in = MDNS_MULTICAST_IPV4_ADDRESS; | |
292 | else | |
293 | addr = p->destination; | |
b4f1862d DM |
294 | fd = manager_mdns_ipv4_fd(s->manager); |
295 | } else if (family == AF_INET6) { | |
84b0ff0e SB |
296 | if (in6_addr_is_null(&p->destination.in6)) |
297 | addr.in6 = MDNS_MULTICAST_IPV6_ADDRESS; | |
298 | else | |
299 | addr = p->destination; | |
b4f1862d DM |
300 | fd = manager_mdns_ipv6_fd(s->manager); |
301 | } else | |
302 | return -EAFNOSUPPORT; | |
303 | if (fd < 0) | |
304 | return fd; | |
305 | ||
84b0ff0e | 306 | r = manager_send(s->manager, fd, s->link->ifindex, family, &addr, p->destination_port ?: MDNS_PORT, NULL, p); |
72290734 TG |
307 | if (r < 0) |
308 | return r; | |
106784eb DM |
309 | |
310 | break; | |
d79677ab | 311 | } |
106784eb DM |
312 | |
313 | default: | |
74b2466e | 314 | return -EAFNOSUPPORT; |
106784eb | 315 | } |
74b2466e | 316 | |
74b2466e LP |
317 | return 1; |
318 | } | |
319 | ||
d79677ab | 320 | int dns_scope_emit_udp(DnsScope *s, int fd, int af, DnsPacket *p) { |
80a62095 DM |
321 | int r; |
322 | ||
323 | assert(s); | |
324 | assert(p); | |
325 | assert(p->protocol == s->protocol); | |
519ef046 | 326 | assert((s->protocol == DNS_PROTOCOL_DNS) == (fd >= 0)); |
80a62095 DM |
327 | |
328 | do { | |
329 | /* If there are multiple linked packets, set the TC bit in all but the last of them */ | |
330 | if (p->more) { | |
331 | assert(p->protocol == DNS_PROTOCOL_MDNS); | |
261f3673 | 332 | dns_packet_set_flags(p, true, true); |
80a62095 DM |
333 | } |
334 | ||
d79677ab | 335 | r = dns_scope_emit_one(s, fd, af, p); |
80a62095 DM |
336 | if (r < 0) |
337 | return r; | |
338 | ||
339 | p = p->more; | |
519ef046 | 340 | } while (p); |
80a62095 DM |
341 | |
342 | return 0; | |
343 | } | |
344 | ||
519ef046 LP |
345 | static int dns_scope_socket( |
346 | DnsScope *s, | |
347 | int type, | |
348 | int family, | |
349 | const union in_addr_union *address, | |
350 | DnsServer *server, | |
91ccab1e IT |
351 | uint16_t port, |
352 | union sockaddr_union *ret_socket_address) { | |
519ef046 | 353 | |
ad867662 | 354 | _cleanup_close_ int fd = -1; |
91ccab1e | 355 | union sockaddr_union sa; |
ad867662 | 356 | socklen_t salen; |
c10d6bdb | 357 | int r, ifindex; |
ad867662 LP |
358 | |
359 | assert(s); | |
be808ea0 | 360 | |
519ef046 LP |
361 | if (server) { |
362 | assert(family == AF_UNSPEC); | |
363 | assert(!address); | |
be808ea0 | 364 | |
2817157b LP |
365 | ifindex = dns_server_ifindex(server); |
366 | ||
7b3bae21 YW |
367 | switch (server->family) { |
368 | case AF_INET: | |
369 | sa = (union sockaddr_union) { | |
370 | .in.sin_family = server->family, | |
371 | .in.sin_port = htobe16(port), | |
372 | .in.sin_addr = server->address.in, | |
373 | }; | |
623a4c97 | 374 | salen = sizeof(sa.in); |
7b3bae21 YW |
375 | break; |
376 | case AF_INET6: | |
377 | sa = (union sockaddr_union) { | |
378 | .in6.sin6_family = server->family, | |
379 | .in6.sin6_port = htobe16(port), | |
380 | .in6.sin6_addr = server->address.in6, | |
381 | .in6.sin6_scope_id = ifindex, | |
382 | }; | |
623a4c97 | 383 | salen = sizeof(sa.in6); |
7b3bae21 YW |
384 | break; |
385 | default: | |
623a4c97 | 386 | return -EAFNOSUPPORT; |
7b3bae21 | 387 | } |
623a4c97 | 388 | } else { |
519ef046 LP |
389 | assert(family != AF_UNSPEC); |
390 | assert(address); | |
391 | ||
2817157b | 392 | ifindex = s->link ? s->link->ifindex : 0; |
623a4c97 | 393 | |
7b3bae21 YW |
394 | switch (family) { |
395 | case AF_INET: | |
396 | sa = (union sockaddr_union) { | |
397 | .in.sin_family = family, | |
398 | .in.sin_port = htobe16(port), | |
399 | .in.sin_addr = address->in, | |
400 | }; | |
623a4c97 | 401 | salen = sizeof(sa.in); |
7b3bae21 YW |
402 | break; |
403 | case AF_INET6: | |
404 | sa = (union sockaddr_union) { | |
405 | .in6.sin6_family = family, | |
406 | .in6.sin6_port = htobe16(port), | |
407 | .in6.sin6_addr = address->in6, | |
408 | .in6.sin6_scope_id = ifindex, | |
409 | }; | |
623a4c97 | 410 | salen = sizeof(sa.in6); |
7b3bae21 YW |
411 | break; |
412 | default: | |
623a4c97 | 413 | return -EAFNOSUPPORT; |
7b3bae21 | 414 | } |
623a4c97 | 415 | } |
ad867662 | 416 | |
0db64366 | 417 | fd = socket(sa.sa.sa_family, type|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
ad867662 LP |
418 | if (fd < 0) |
419 | return -errno; | |
420 | ||
0db64366 | 421 | if (type == SOCK_STREAM) { |
2ff48e98 | 422 | r = setsockopt_int(fd, IPPROTO_TCP, TCP_NODELAY, true); |
0db64366 | 423 | if (r < 0) |
2ff48e98 | 424 | return r; |
0db64366 | 425 | } |
623a4c97 LP |
426 | |
427 | if (s->link) { | |
5d0fe423 LP |
428 | r = socket_set_unicast_if(fd, sa.sa.sa_family, ifindex); |
429 | if (r < 0) | |
430 | return r; | |
623a4c97 LP |
431 | } |
432 | ||
433 | if (s->protocol == DNS_PROTOCOL_LLMNR) { | |
bf3f1271 | 434 | /* RFC 4795, section 2.5 requires the TTL to be set to 1 */ |
5d0fe423 LP |
435 | r = socket_set_ttl(fd, sa.sa.sa_family, 1); |
436 | if (r < 0) | |
437 | return r; | |
623a4c97 | 438 | } |
ad867662 | 439 | |
9fcdab9c YW |
440 | if (type == SOCK_DGRAM) { |
441 | /* Set IP_RECVERR or IPV6_RECVERR to get ICMP error feedback. See discussion in #10345. */ | |
5d0fe423 LP |
442 | r = socket_set_recverr(fd, sa.sa.sa_family, true); |
443 | if (r < 0) | |
444 | return r; | |
c9e69182 | 445 | |
5d0fe423 LP |
446 | r = socket_set_recvpktinfo(fd, sa.sa.sa_family, true); |
447 | if (r < 0) | |
448 | return r; | |
eb170e75 LP |
449 | |
450 | /* Turn of path MTU discovery for security reasons */ | |
451 | r = socket_disable_pmtud(fd, sa.sa.sa_family); | |
452 | if (r < 0) | |
453 | log_debug_errno(r, "Failed to disable UDP PMTUD, ignoring: %m"); | |
20a001bd LP |
454 | |
455 | /* Learn about fragmentation taking place */ | |
456 | r = socket_set_recvfragsize(fd, sa.sa.sa_family, true); | |
457 | if (r < 0) | |
458 | log_debug_errno(r, "Failed to enable fragment size reception, ignoring: %m"); | |
9fcdab9c YW |
459 | } |
460 | ||
91ccab1e IT |
461 | if (ret_socket_address) |
462 | *ret_socket_address = sa; | |
463 | else { | |
d301c523 LP |
464 | bool bound = false; |
465 | ||
466 | /* Let's temporarily bind the socket to the specified ifindex. The kernel currently takes | |
467 | * only the SO_BINDTODEVICE/SO_BINDTOINDEX ifindex into account when making routing decisions | |
468 | * in connect() — and not IP_UNICAST_IF. We don't really want any of the other semantics of | |
469 | * SO_BINDTODEVICE/SO_BINDTOINDEX, hence we immediately unbind the socket after the fact | |
470 | * again. | |
471 | * | |
472 | * As a special exception we don't do this if we notice that the specified IP address is on | |
473 | * the local host. SO_BINDTODEVICE in combination with destination addresses on the local | |
474 | * host result in EHOSTUNREACH, since Linux won't send the packets out of the specified | |
475 | * interface, but delivers them directly to the local socket. */ | |
476 | if (s->link && | |
477 | !manager_find_link_address(s->manager, sa.sa.sa_family, sockaddr_in_addr(&sa.sa))) { | |
478 | r = socket_bind_to_ifindex(fd, ifindex); | |
479 | if (r < 0) | |
480 | return r; | |
481 | ||
482 | bound = true; | |
483 | } | |
484 | ||
91ccab1e IT |
485 | r = connect(fd, &sa.sa, salen); |
486 | if (r < 0 && errno != EINPROGRESS) | |
487 | return -errno; | |
d301c523 LP |
488 | |
489 | if (bound) { | |
490 | r = socket_bind_to_ifindex(fd, 0); | |
491 | if (r < 0) | |
492 | return r; | |
493 | } | |
91ccab1e | 494 | } |
ad867662 | 495 | |
c10d6bdb | 496 | return TAKE_FD(fd); |
ad867662 LP |
497 | } |
498 | ||
da9de738 YW |
499 | int dns_scope_socket_udp(DnsScope *s, DnsServer *server) { |
500 | return dns_scope_socket(s, SOCK_DGRAM, AF_UNSPEC, NULL, server, dns_server_port(server), NULL); | |
0db64366 TG |
501 | } |
502 | ||
91ccab1e | 503 | int dns_scope_socket_tcp(DnsScope *s, int family, const union in_addr_union *address, DnsServer *server, uint16_t port, union sockaddr_union *ret_socket_address) { |
5238e957 | 504 | /* If ret_socket_address is not NULL, the caller is responsible |
91ccab1e IT |
505 | * for calling connect() or sendmsg(). This is required by TCP |
506 | * Fast Open, to be able to send the initial SYN packet along | |
507 | * with the first data packet. */ | |
508 | return dns_scope_socket(s, SOCK_STREAM, family, address, server, port, ret_socket_address); | |
0db64366 TG |
509 | } |
510 | ||
c78735eb | 511 | static DnsScopeMatch match_link_local_reverse_lookups(const char *domain) { |
17508549 LP |
512 | assert(domain); |
513 | ||
514 | if (dns_name_endswith(domain, "254.169.in-addr.arpa") > 0) | |
515 | return DNS_SCOPE_YES_BASE + 4; /* 4 labels match */ | |
516 | ||
517 | if (dns_name_endswith(domain, "8.e.f.ip6.arpa") > 0 || | |
518 | dns_name_endswith(domain, "9.e.f.ip6.arpa") > 0 || | |
519 | dns_name_endswith(domain, "a.e.f.ip6.arpa") > 0 || | |
520 | dns_name_endswith(domain, "b.e.f.ip6.arpa") > 0) | |
521 | return DNS_SCOPE_YES_BASE + 5; /* 5 labels match */ | |
522 | ||
523 | return _DNS_SCOPE_MATCH_INVALID; | |
524 | } | |
525 | ||
13eb76ef LP |
526 | static DnsScopeMatch match_subnet_reverse_lookups( |
527 | DnsScope *s, | |
528 | const char *domain, | |
529 | bool exclude_own) { | |
530 | ||
531 | union in_addr_union ia; | |
13eb76ef LP |
532 | int f, r; |
533 | ||
534 | assert(s); | |
535 | assert(domain); | |
536 | ||
537 | /* Checks whether the specified domain is a reverse address domain (i.e. in the .in-addr.arpa or | |
538 | * .ip6.arpa area), and if so, whether the address matches any of the local subnets of the link the | |
539 | * scope is associated with. If so, our scope should consider itself relevant for any lookup in the | |
540 | * domain, since it apparently refers to hosts on this link's subnet. | |
541 | * | |
542 | * If 'exclude_own' is true this will return DNS_SCOPE_NO for any IP addresses assigned locally. This | |
543 | * is useful for LLMNR/mDNS as we never want to look up our own hostname on LLMNR/mDNS but always use | |
544 | * the locally synthesized one. */ | |
545 | ||
546 | if (!s->link) | |
547 | return _DNS_SCOPE_MATCH_INVALID; /* No link, hence no local addresses to check */ | |
548 | ||
549 | r = dns_name_address(domain, &f, &ia); | |
550 | if (r < 0) | |
551 | log_debug_errno(r, "Failed to determine whether '%s' is an address domain: %m", domain); | |
552 | if (r <= 0) | |
553 | return _DNS_SCOPE_MATCH_INVALID; | |
554 | ||
555 | if (s->family != AF_UNSPEC && f != s->family) | |
556 | return _DNS_SCOPE_MATCH_INVALID; /* Don't look for IPv4 addresses on LLMNR/mDNS over IPv6 and vice versa */ | |
557 | ||
558 | LIST_FOREACH(addresses, a, s->link->addresses) { | |
559 | ||
560 | if (a->family != f) | |
561 | continue; | |
562 | ||
563 | /* Equals our own address? nah, let's not use this scope. The local synthesizer will pick it up for us. */ | |
564 | if (exclude_own && | |
565 | in_addr_equal(f, &a->in_addr, &ia) > 0) | |
566 | return DNS_SCOPE_NO; | |
567 | ||
568 | if (a->prefixlen == UCHAR_MAX) /* don't know subnet mask */ | |
569 | continue; | |
570 | ||
571 | /* Check if the address is in the local subnet */ | |
572 | r = in_addr_prefix_covers(f, &a->in_addr, a->prefixlen, &ia); | |
573 | if (r < 0) | |
574 | log_debug_errno(r, "Failed to determine whether link address covers lookup address '%s': %m", domain); | |
575 | if (r > 0) | |
576 | /* Note that we only claim zero labels match. This is so that this is at the same | |
577 | * priority a DNS scope with "." as routing domain is. */ | |
578 | return DNS_SCOPE_YES_BASE + 0; | |
579 | } | |
580 | ||
581 | return _DNS_SCOPE_MATCH_INVALID; | |
582 | } | |
583 | ||
a97a3b25 LP |
584 | DnsScopeMatch dns_scope_good_domain( |
585 | DnsScope *s, | |
176a9a2c | 586 | DnsQuery *q) { |
a97a3b25 | 587 | |
176a9a2c | 588 | DnsQuestion *question; |
176a9a2c YW |
589 | const char *domain; |
590 | uint64_t flags; | |
591 | int ifindex; | |
74b2466e | 592 | |
a97a3b25 LP |
593 | /* This returns the following return values: |
594 | * | |
595 | * DNS_SCOPE_NO → This scope is not suitable for lookups of this domain, at all | |
596 | * DNS_SCOPE_MAYBE → This scope is suitable, but only if nothing else wants it | |
597 | * DNS_SCOPE_YES_BASE+n → This scope is suitable, and 'n' suffix labels match | |
598 | * | |
599 | * (The idea is that the caller will only use the scopes with the longest 'n' returned. If no scopes return | |
600 | * DNS_SCOPE_YES_BASE+n, then it should use those which returned DNS_SCOPE_MAYBE. It should never use those | |
601 | * which returned DNS_SCOPE_NO.) | |
602 | */ | |
603 | ||
74b2466e | 604 | assert(s); |
176a9a2c YW |
605 | assert(q); |
606 | ||
607 | question = dns_query_question_for_protocol(q, s->protocol); | |
608 | if (!question) | |
609 | return DNS_SCOPE_NO; | |
610 | ||
611 | domain = dns_question_first_name(question); | |
612 | if (!domain) | |
613 | return DNS_SCOPE_NO; | |
614 | ||
615 | ifindex = q->ifindex; | |
616 | flags = q->flags; | |
74b2466e | 617 | |
3d334c40 ZJS |
618 | /* Checks if the specified domain is something to look up on this scope. Note that this accepts |
619 | * non-qualified hostnames, i.e. those without any search path suffixed. */ | |
28b9b764 | 620 | |
51323288 LP |
621 | if (ifindex != 0 && (!s->link || s->link->ifindex != ifindex)) |
622 | return DNS_SCOPE_NO; | |
623 | ||
43fc4baa | 624 | if ((SD_RESOLVED_FLAGS_MAKE(s->protocol, s->family, false, false) & flags) == 0) |
51323288 LP |
625 | return DNS_SCOPE_NO; |
626 | ||
fbbc7218 LP |
627 | /* Never resolve any loopback hostname or IP address via DNS, LLMNR or mDNS. Instead, always rely on |
628 | * synthesized RRs for these. */ | |
78c6a153 LP |
629 | if (is_localhost(domain) || |
630 | dns_name_endswith(domain, "127.in-addr.arpa") > 0 || | |
9436e8ca LP |
631 | 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) |
632 | return DNS_SCOPE_NO; | |
633 | ||
f4526f82 LP |
634 | /* Never respond to some of the domains listed in RFC6303 + RFC6761 */ |
635 | if (dns_name_dont_resolve(domain)) | |
7bcffc2e LP |
636 | return DNS_SCOPE_NO; |
637 | ||
ee18f107 LP |
638 | /* Never go to network for the _gateway or _outbound domain — they're something special, synthesized locally. */ |
639 | if (is_gateway_hostname(domain) || is_outbound_hostname(domain)) | |
fbbc7218 LP |
640 | return DNS_SCOPE_NO; |
641 | ||
106784eb | 642 | switch (s->protocol) { |
801ad6a6 | 643 | |
613dca46 | 644 | case DNS_PROTOCOL_DNS: { |
fea46786 | 645 | bool has_search_domains = false; |
13eb76ef | 646 | DnsScopeMatch m; |
a97a3b25 | 647 | int n_best = -1; |
613dca46 | 648 | |
30fa3aa1 YW |
649 | if (dns_name_is_empty(domain)) { |
650 | DnsResourceKey *t; | |
651 | bool found = false; | |
652 | ||
653 | /* Refuse empty name if only A and/or AAAA records are requested. */ | |
654 | ||
655 | DNS_QUESTION_FOREACH(t, question) | |
656 | if (!IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_AAAA)) { | |
657 | found = true; | |
658 | break; | |
659 | } | |
660 | ||
661 | if (!found) | |
662 | return DNS_SCOPE_NO; | |
663 | } | |
664 | ||
613dca46 | 665 | /* Never route things to scopes that lack DNS servers */ |
f76fa088 | 666 | if (!dns_scope_get_dns_server(s)) |
613dca46 LP |
667 | return DNS_SCOPE_NO; |
668 | ||
669 | /* Always honour search domains for routing queries, except if this scope lacks DNS servers. Note that | |
670 | * we return DNS_SCOPE_YES here, rather than just DNS_SCOPE_MAYBE, which means other wildcard scopes | |
671 | * won't be considered anymore. */ | |
fea46786 LP |
672 | LIST_FOREACH(domains, d, dns_scope_get_search_domains(s)) { |
673 | ||
674 | if (!d->route_only && !dns_name_is_root(d->name)) | |
675 | has_search_domains = true; | |
676 | ||
a97a3b25 LP |
677 | if (dns_name_endswith(domain, d->name) > 0) { |
678 | int c; | |
679 | ||
680 | c = dns_name_count_labels(d->name); | |
681 | if (c < 0) | |
682 | continue; | |
683 | ||
684 | if (c > n_best) | |
685 | n_best = c; | |
686 | } | |
fea46786 LP |
687 | } |
688 | ||
689 | /* If there's a true search domain defined for this scope, and the query is single-label, | |
690 | * then let's resolve things here, prefereably. Note that LLMNR considers itself | |
691 | * authoritative for single-label names too, at the same preference, see below. */ | |
692 | if (has_search_domains && dns_name_is_single_label(domain)) | |
693 | return DNS_SCOPE_YES_BASE + 1; | |
a97a3b25 | 694 | |
ff0a5070 JM |
695 | /* If ResolveUnicastSingleLabel=yes and the query is single-label, then bump match result |
696 | to prevent LLMNR monopoly among candidates. */ | |
697 | if (s->manager->resolve_unicast_single_label && dns_name_is_single_label(domain)) | |
698 | return DNS_SCOPE_YES_BASE + 1; | |
699 | ||
a97a3b25 LP |
700 | /* Let's return the number of labels in the best matching result */ |
701 | if (n_best >= 0) { | |
702 | assert(n_best <= DNS_SCOPE_YES_END - DNS_SCOPE_YES_BASE); | |
703 | return DNS_SCOPE_YES_BASE + n_best; | |
704 | } | |
613dca46 | 705 | |
c78735eb LP |
706 | /* Exclude link-local IP ranges */ |
707 | if (match_link_local_reverse_lookups(domain) >= DNS_SCOPE_YES_BASE || | |
708 | /* If networks use .local in their private setups, they are supposed to also add .local | |
709 | * to their search domains, which we already checked above. Otherwise, we consider .local | |
710 | * specific to mDNS and won't send such queries ordinary DNS servers. */ | |
711 | dns_name_endswith(domain, "local") > 0) | |
613dca46 | 712 | return DNS_SCOPE_NO; |
801ad6a6 | 713 | |
b480543c | 714 | /* If the IP address to look up matches the local subnet, then implicitly synthesizes |
13eb76ef LP |
715 | * DNS_SCOPE_YES_BASE + 0 on this interface, i.e. preferably resolve IP addresses via the DNS |
716 | * server belonging to this interface. */ | |
717 | m = match_subnet_reverse_lookups(s, domain, false); | |
718 | if (m >= 0) | |
719 | return m; | |
720 | ||
c78735eb LP |
721 | /* If there was no match at all, then see if this scope is suitable as default route. */ |
722 | if (!dns_scope_is_default_route(s)) | |
723 | return DNS_SCOPE_NO; | |
1716f6dc | 724 | |
c78735eb | 725 | return DNS_SCOPE_MAYBE; |
613dca46 | 726 | } |
1716f6dc | 727 | |
17508549 LP |
728 | case DNS_PROTOCOL_MDNS: { |
729 | DnsScopeMatch m; | |
730 | ||
c78735eb | 731 | m = match_link_local_reverse_lookups(domain); |
17508549 LP |
732 | if (m >= 0) |
733 | return m; | |
734 | ||
13eb76ef LP |
735 | m = match_subnet_reverse_lookups(s, domain, true); |
736 | if (m >= 0) | |
737 | return m; | |
738 | ||
78c6a153 | 739 | if ((s->family == AF_INET && dns_name_endswith(domain, "in-addr.arpa") > 0) || |
17508549 LP |
740 | (s->family == AF_INET6 && dns_name_endswith(domain, "ip6.arpa") > 0)) |
741 | return DNS_SCOPE_MAYBE; | |
742 | ||
743 | if ((dns_name_endswith(domain, "local") > 0 && /* only resolve names ending in .local via mDNS */ | |
78c6a153 LP |
744 | dns_name_equal(domain, "local") == 0 && /* but not the single-label "local" name itself */ |
745 | manager_is_own_hostname(s->manager, domain) <= 0)) /* never resolve the local hostname via mDNS */ | |
17508549 | 746 | return DNS_SCOPE_YES_BASE + 1; /* Return +1, as the top-level .local domain matches, i.e. one label */ |
74b2466e LP |
747 | |
748 | return DNS_SCOPE_NO; | |
17508549 LP |
749 | } |
750 | ||
751 | case DNS_PROTOCOL_LLMNR: { | |
752 | DnsScopeMatch m; | |
753 | ||
c78735eb | 754 | m = match_link_local_reverse_lookups(domain); |
17508549 LP |
755 | if (m >= 0) |
756 | return m; | |
74b2466e | 757 | |
13eb76ef LP |
758 | m = match_subnet_reverse_lookups(s, domain, true); |
759 | if (m >= 0) | |
760 | return m; | |
761 | ||
78c6a153 | 762 | if ((s->family == AF_INET && dns_name_endswith(domain, "in-addr.arpa") > 0) || |
17508549 LP |
763 | (s->family == AF_INET6 && dns_name_endswith(domain, "ip6.arpa") > 0)) |
764 | return DNS_SCOPE_MAYBE; | |
765 | ||
766 | if ((dns_name_is_single_label(domain) && /* only resolve single label names via LLMNR */ | |
fbbc7218 | 767 | !is_gateway_hostname(domain) && /* don't resolve "_gateway" with LLMNR, let local synthesizing logic handle that */ |
ee18f107 | 768 | !is_outbound_hostname(domain) && /* similar for "_outbound" */ |
088648d0 | 769 | dns_name_equal(domain, "local") == 0 && /* don't resolve "local" with LLMNR, it's the top-level domain of mDNS after all, see above */ |
78c6a153 | 770 | manager_is_own_hostname(s->manager, domain) <= 0)) /* never resolve the local hostname via LLMNR */ |
fea46786 LP |
771 | return DNS_SCOPE_YES_BASE + 1; /* Return +1, as we consider ourselves authoritative |
772 | * for single-label names, i.e. one label. This is | |
3b5bd7d6 | 773 | * particularly relevant as it means a "." route on some |
fea46786 LP |
774 | * other scope won't pull all traffic away from |
775 | * us. (If people actually want to pull traffic away | |
776 | * from us they should turn off LLMNR on the | |
777 | * link). Note that unicast DNS scopes with search | |
778 | * domains also consider themselves authoritative for | |
779 | * single-label domains, at the same preference (see | |
780 | * above). */ | |
74b2466e | 781 | |
1716f6dc | 782 | return DNS_SCOPE_NO; |
17508549 | 783 | } |
74b2466e | 784 | |
106784eb | 785 | default: |
04499a70 | 786 | assert_not_reached(); |
106784eb | 787 | } |
1716f6dc LP |
788 | } |
789 | ||
011696f7 LP |
790 | bool dns_scope_good_key(DnsScope *s, const DnsResourceKey *key) { |
791 | int key_family; | |
792 | ||
1716f6dc LP |
793 | assert(s); |
794 | assert(key); | |
795 | ||
d8f3836e LP |
796 | /* Check if it makes sense to resolve the specified key on this scope. Note that this call assumes a |
797 | * fully qualified name, i.e. the search suffixes already appended. */ | |
28b9b764 | 798 | |
d8f3836e | 799 | if (!IN_SET(key->class, DNS_CLASS_IN, DNS_CLASS_ANY)) |
011696f7 LP |
800 | return false; |
801 | ||
28b9b764 LP |
802 | if (s->protocol == DNS_PROTOCOL_DNS) { |
803 | ||
3b5bd7d6 ZJS |
804 | /* On classic DNS, looking up non-address RRs is always fine. (Specifically, we want to |
805 | * permit looking up DNSKEY and DS records on the root and top-level domains.) */ | |
28b9b764 LP |
806 | if (!dns_resource_key_is_address(key)) |
807 | return true; | |
808 | ||
3b5bd7d6 ZJS |
809 | /* Unless explicitly overridden, we refuse to look up A and AAAA RRs on the root and |
810 | * single-label domains, under the assumption that those should be resolved via LLMNR or | |
811 | * search path only, and should not be leaked onto the internet. */ | |
812 | const char* name = dns_resource_key_name(key); | |
813 | ||
814 | if (!s->manager->resolve_unicast_single_label && | |
815 | dns_name_is_single_label(name)) | |
816 | return false; | |
817 | ||
818 | return !dns_name_is_root(name); | |
28b9b764 | 819 | } |
1716f6dc | 820 | |
73b6fc77 LP |
821 | /* Never route DNSSEC RR queries to LLMNR/mDNS scopes */ |
822 | if (dns_type_is_dnssec(key->type)) | |
823 | return false; | |
824 | ||
d8f3836e | 825 | /* On mDNS and LLMNR, send A and AAAA queries only on the respective scopes */ |
1716f6dc | 826 | |
011696f7 LP |
827 | key_family = dns_type_to_af(key->type); |
828 | if (key_family < 0) | |
829 | return true; | |
1716f6dc | 830 | |
011696f7 | 831 | return key_family == s->family; |
1716f6dc LP |
832 | } |
833 | ||
0db4c90a | 834 | static int dns_scope_multicast_membership(DnsScope *s, bool b, struct in_addr in, struct in6_addr in6) { |
1716f6dc LP |
835 | int fd; |
836 | ||
5ba73e9b | 837 | assert(s); |
5ba73e9b LP |
838 | assert(s->link); |
839 | ||
1716f6dc LP |
840 | if (s->family == AF_INET) { |
841 | struct ip_mreqn mreqn = { | |
0db4c90a | 842 | .imr_multiaddr = in, |
1716f6dc LP |
843 | .imr_ifindex = s->link->ifindex, |
844 | }; | |
845 | ||
d37baf40 DR |
846 | if (s->protocol == DNS_PROTOCOL_LLMNR) |
847 | fd = manager_llmnr_ipv4_udp_fd(s->manager); | |
848 | else | |
849 | fd = manager_mdns_ipv4_fd(s->manager); | |
850 | ||
1716f6dc LP |
851 | if (fd < 0) |
852 | return fd; | |
853 | ||
7b4c2ee7 LP |
854 | /* Always first try to drop membership before we add |
855 | * one. This is necessary on some devices, such as | |
856 | * veth. */ | |
857 | if (b) | |
dc751688 | 858 | (void) setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)); |
7b4c2ee7 | 859 | |
1716f6dc LP |
860 | if (setsockopt(fd, IPPROTO_IP, b ? IP_ADD_MEMBERSHIP : IP_DROP_MEMBERSHIP, &mreqn, sizeof(mreqn)) < 0) |
861 | return -errno; | |
862 | ||
863 | } else if (s->family == AF_INET6) { | |
864 | struct ipv6_mreq mreq = { | |
0db4c90a | 865 | .ipv6mr_multiaddr = in6, |
1716f6dc LP |
866 | .ipv6mr_interface = s->link->ifindex, |
867 | }; | |
868 | ||
d37baf40 DR |
869 | if (s->protocol == DNS_PROTOCOL_LLMNR) |
870 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
871 | else | |
872 | fd = manager_mdns_ipv6_fd(s->manager); | |
873 | ||
1716f6dc LP |
874 | if (fd < 0) |
875 | return fd; | |
876 | ||
7b4c2ee7 | 877 | if (b) |
dc751688 | 878 | (void) setsockopt(fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); |
7b4c2ee7 | 879 | |
1716f6dc LP |
880 | if (setsockopt(fd, IPPROTO_IPV6, b ? IPV6_ADD_MEMBERSHIP : IPV6_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) |
881 | return -errno; | |
882 | } else | |
883 | return -EAFNOSUPPORT; | |
884 | ||
885 | return 0; | |
74b2466e | 886 | } |
623a4c97 | 887 | |
0db4c90a | 888 | int dns_scope_llmnr_membership(DnsScope *s, bool b) { |
f471bc11 | 889 | assert(s); |
0db4c90a DM |
890 | |
891 | if (s->protocol != DNS_PROTOCOL_LLMNR) | |
892 | return 0; | |
893 | ||
894 | return dns_scope_multicast_membership(s, b, LLMNR_MULTICAST_IPV4_ADDRESS, LLMNR_MULTICAST_IPV6_ADDRESS); | |
895 | } | |
896 | ||
897 | int dns_scope_mdns_membership(DnsScope *s, bool b) { | |
f471bc11 | 898 | assert(s); |
0db4c90a DM |
899 | |
900 | if (s->protocol != DNS_PROTOCOL_MDNS) | |
901 | return 0; | |
902 | ||
903 | return dns_scope_multicast_membership(s, b, MDNS_MULTICAST_IPV4_ADDRESS, MDNS_MULTICAST_IPV6_ADDRESS); | |
904 | } | |
905 | ||
3b991089 | 906 | int dns_scope_make_reply_packet( |
ec2c5e43 LP |
907 | DnsScope *s, |
908 | uint16_t id, | |
909 | int rcode, | |
910 | DnsQuestion *q, | |
911 | DnsAnswer *answer, | |
912 | DnsAnswer *soa, | |
913 | bool tentative, | |
914 | DnsPacket **ret) { | |
915 | ||
623a4c97 | 916 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
6f76e68a | 917 | unsigned n_answer = 0, n_soa = 0; |
623a4c97 | 918 | int r; |
bb4e030f | 919 | bool c_or_aa; |
623a4c97 LP |
920 | |
921 | assert(s); | |
a4076574 | 922 | assert(ret); |
623a4c97 | 923 | |
501e8eb0 LP |
924 | if (dns_question_isempty(q) && |
925 | dns_answer_isempty(answer) && | |
926 | dns_answer_isempty(soa)) | |
623a4c97 LP |
927 | return -EINVAL; |
928 | ||
51027656 | 929 | r = dns_packet_new(&p, s->protocol, 0, DNS_PACKET_SIZE_MAX); |
623a4c97 LP |
930 | if (r < 0) |
931 | return r; | |
932 | ||
bb4e030f SB |
933 | /* mDNS answers must have the Authoritative Answer bit set, see RFC 6762, section 18.4. */ |
934 | c_or_aa = s->protocol == DNS_PROTOCOL_MDNS; | |
935 | ||
623a4c97 | 936 | DNS_PACKET_HEADER(p)->id = id; |
ea917db9 LP |
937 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( |
938 | 1 /* qr */, | |
939 | 0 /* opcode */, | |
bb4e030f | 940 | c_or_aa, |
ea917db9 | 941 | 0 /* tc */, |
ec2c5e43 | 942 | tentative, |
ea917db9 LP |
943 | 0 /* (ra) */, |
944 | 0 /* (ad) */, | |
945 | 0 /* (cd) */, | |
946 | rcode)); | |
623a4c97 | 947 | |
f471bc11 LP |
948 | r = dns_packet_append_question(p, q); |
949 | if (r < 0) | |
950 | return r; | |
951 | DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q)); | |
8bf52d3d | 952 | |
6f76e68a | 953 | r = dns_packet_append_answer(p, answer, &n_answer); |
f471bc11 LP |
954 | if (r < 0) |
955 | return r; | |
6f76e68a | 956 | DNS_PACKET_HEADER(p)->ancount = htobe16(n_answer); |
8bf52d3d | 957 | |
6f76e68a | 958 | r = dns_packet_append_answer(p, soa, &n_soa); |
f471bc11 LP |
959 | if (r < 0) |
960 | return r; | |
6f76e68a | 961 | DNS_PACKET_HEADER(p)->arcount = htobe16(n_soa); |
623a4c97 | 962 | |
1cc6c93a | 963 | *ret = TAKE_PTR(p); |
623a4c97 LP |
964 | |
965 | return 0; | |
966 | } | |
967 | ||
a4076574 | 968 | static void dns_scope_verify_conflicts(DnsScope *s, DnsPacket *p) { |
2a3900d7 LP |
969 | DnsResourceRecord *rr; |
970 | DnsResourceKey *key; | |
a4076574 LP |
971 | |
972 | assert(s); | |
973 | assert(p); | |
974 | ||
2a3900d7 LP |
975 | DNS_QUESTION_FOREACH(key, p->question) |
976 | dns_zone_verify_conflicts(&s->zone, key); | |
977 | ||
978 | DNS_ANSWER_FOREACH(rr, p->answer) | |
979 | dns_zone_verify_conflicts(&s->zone, rr->key); | |
a4076574 LP |
980 | } |
981 | ||
623a4c97 | 982 | void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) { |
8bf52d3d | 983 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL; |
b30bf55d | 984 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; |
5032b16d | 985 | DnsResourceKey *key = NULL; |
ec2c5e43 | 986 | bool tentative = false; |
b30bf55d | 987 | int r; |
623a4c97 LP |
988 | |
989 | assert(s); | |
990 | assert(p); | |
991 | ||
992 | if (p->protocol != DNS_PROTOCOL_LLMNR) | |
993 | return; | |
994 | ||
2442b93d LP |
995 | if (p->ipproto == IPPROTO_UDP) { |
996 | /* Don't accept UDP queries directed to anything but | |
997 | * the LLMNR multicast addresses. See RFC 4795, | |
d076c6f9 | 998 | * section 2.5. */ |
2442b93d | 999 | |
94876904 | 1000 | if (p->family == AF_INET && !in4_addr_equal(&p->destination.in, &LLMNR_MULTICAST_IPV4_ADDRESS)) |
2442b93d LP |
1001 | return; |
1002 | ||
94876904 | 1003 | if (p->family == AF_INET6 && !in6_addr_equal(&p->destination.in6, &LLMNR_MULTICAST_IPV6_ADDRESS)) |
2442b93d LP |
1004 | return; |
1005 | } | |
1006 | ||
623a4c97 LP |
1007 | r = dns_packet_extract(p); |
1008 | if (r < 0) { | |
b30bf55d | 1009 | log_debug_errno(r, "Failed to extract resource records from incoming packet: %m"); |
623a4c97 LP |
1010 | return; |
1011 | } | |
1012 | ||
8b757a38 | 1013 | if (DNS_PACKET_LLMNR_C(p)) { |
a4076574 LP |
1014 | /* Somebody notified us about a possible conflict */ |
1015 | dns_scope_verify_conflicts(s, p); | |
ea917db9 LP |
1016 | return; |
1017 | } | |
1018 | ||
055acd4d YW |
1019 | if (dns_question_size(p->question) != 1) |
1020 | return (void) log_debug("Received LLMNR query without question or multiple questions, ignoring."); | |
1021 | ||
ab715ddb | 1022 | key = dns_question_first_key(p->question); |
5032b16d | 1023 | |
97ebebbc | 1024 | r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative); |
623a4c97 | 1025 | if (r < 0) { |
105a1a36 | 1026 | log_debug_errno(r, "Failed to look up key: %m"); |
623a4c97 LP |
1027 | return; |
1028 | } | |
1029 | if (r == 0) | |
1030 | return; | |
1031 | ||
fcf57f9c LP |
1032 | if (answer) |
1033 | dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0); | |
af93291c | 1034 | |
ec2c5e43 | 1035 | r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, soa, tentative, &reply); |
623a4c97 | 1036 | if (r < 0) { |
da927ba9 | 1037 | log_debug_errno(r, "Failed to build reply packet: %m"); |
623a4c97 LP |
1038 | return; |
1039 | } | |
1040 | ||
b30bf55d | 1041 | if (stream) { |
623a4c97 | 1042 | r = dns_stream_write_packet(stream, reply); |
b30bf55d LP |
1043 | if (r < 0) { |
1044 | log_debug_errno(r, "Failed to enqueue reply packet: %m"); | |
1045 | return; | |
1046 | } | |
1047 | ||
1048 | /* Let's take an extra reference on this stream, so that it stays around after returning. The reference | |
1049 | * will be dangling until the stream is disconnected, and the default completion handler of the stream | |
1050 | * will then unref the stream and destroy it */ | |
1051 | if (DNS_STREAM_QUEUED(stream)) | |
1052 | dns_stream_ref(stream); | |
1053 | } else { | |
1054 | int fd; | |
1055 | ||
7994ac1d | 1056 | if (!ratelimit_below(&s->ratelimit)) |
aea2429d LP |
1057 | return; |
1058 | ||
623a4c97 LP |
1059 | if (p->family == AF_INET) |
1060 | fd = manager_llmnr_ipv4_udp_fd(s->manager); | |
1061 | else if (p->family == AF_INET6) | |
1062 | fd = manager_llmnr_ipv6_udp_fd(s->manager); | |
1063 | else { | |
1064 | log_debug("Unknown protocol"); | |
1065 | return; | |
1066 | } | |
1067 | if (fd < 0) { | |
da927ba9 | 1068 | log_debug_errno(fd, "Failed to get reply socket: %m"); |
623a4c97 LP |
1069 | return; |
1070 | } | |
1071 | ||
6e068472 LP |
1072 | /* Note that we always immediately reply to all LLMNR |
1073 | * requests, and do not wait any time, since we | |
1074 | * verified uniqueness for all records. Also see RFC | |
1075 | * 4795, Section 2.7 */ | |
1076 | ||
b30bf55d LP |
1077 | r = manager_send(s->manager, fd, p->ifindex, p->family, &p->sender, p->sender_port, NULL, reply); |
1078 | if (r < 0) { | |
1079 | log_debug_errno(r, "Failed to send reply packet: %m"); | |
1080 | return; | |
1081 | } | |
623a4c97 LP |
1082 | } |
1083 | } | |
ec2c5e43 | 1084 | |
775ae354 LP |
1085 | DnsTransaction *dns_scope_find_transaction( |
1086 | DnsScope *scope, | |
1087 | DnsResourceKey *key, | |
1088 | uint64_t query_flags) { | |
1089 | ||
03677889 | 1090 | DnsTransaction *first; |
ec2c5e43 LP |
1091 | |
1092 | assert(scope); | |
f52e61da | 1093 | assert(key); |
ec2c5e43 | 1094 | |
775ae354 LP |
1095 | /* Iterate through the list of transactions with a matching key */ |
1096 | first = hashmap_get(scope->transactions_by_key, key); | |
1097 | LIST_FOREACH(transactions_by_key, t, first) { | |
1098 | ||
1099 | /* These four flags must match exactly: we cannot use a validated response for a | |
1100 | * non-validating client, and we cannot use a non-validated response for a validating | |
1101 | * client. Similar, if the sources don't match things aren't usable either. */ | |
1102 | if (((query_flags ^ t->query_flags) & | |
1103 | (SD_RESOLVED_NO_VALIDATE| | |
1104 | SD_RESOLVED_NO_ZONE| | |
1105 | SD_RESOLVED_NO_TRUST_ANCHOR| | |
1106 | SD_RESOLVED_NO_NETWORK)) != 0) | |
1107 | continue; | |
1108 | ||
1109 | /* We can reuse a primary query if a regular one is requested, but not vice versa */ | |
1110 | if ((query_flags & SD_RESOLVED_REQUIRE_PRIMARY) && | |
1111 | !(t->query_flags & SD_RESOLVED_REQUIRE_PRIMARY)) | |
1112 | continue; | |
1113 | ||
1114 | /* Don't reuse a transaction that allowed caching when we got told not to use it */ | |
1115 | if ((query_flags & SD_RESOLVED_NO_CACHE) && | |
1116 | !(t->query_flags & SD_RESOLVED_NO_CACHE)) | |
1117 | continue; | |
1118 | ||
fa027117 | 1119 | /* If we are asked to clamp ttls an the existing transaction doesn't do it, we can't |
775ae354 LP |
1120 | * reuse */ |
1121 | if ((query_flags & SD_RESOLVED_CLAMP_TTL) && | |
1122 | !(t->query_flags & SD_RESOLVED_CLAMP_TTL)) | |
1123 | continue; | |
1124 | ||
1125 | return t; | |
1126 | } | |
ec2c5e43 | 1127 | |
775ae354 | 1128 | return NULL; |
ec2c5e43 | 1129 | } |
a4076574 LP |
1130 | |
1131 | static int dns_scope_make_conflict_packet( | |
1132 | DnsScope *s, | |
1133 | DnsResourceRecord *rr, | |
1134 | DnsPacket **ret) { | |
1135 | ||
1136 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1137 | int r; | |
1138 | ||
1139 | assert(s); | |
1140 | assert(rr); | |
1141 | assert(ret); | |
1142 | ||
51027656 | 1143 | r = dns_packet_new(&p, s->protocol, 0, DNS_PACKET_SIZE_MAX); |
a4076574 LP |
1144 | if (r < 0) |
1145 | return r; | |
1146 | ||
1147 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( | |
1148 | 0 /* qr */, | |
1149 | 0 /* opcode */, | |
1150 | 1 /* conflict */, | |
1151 | 0 /* tc */, | |
1152 | 0 /* t */, | |
1153 | 0 /* (ra) */, | |
1154 | 0 /* (ad) */, | |
1155 | 0 /* (cd) */, | |
1156 | 0)); | |
fe2dfc8b DM |
1157 | |
1158 | /* For mDNS, the transaction ID should always be 0 */ | |
1159 | if (s->protocol != DNS_PROTOCOL_MDNS) | |
1160 | random_bytes(&DNS_PACKET_HEADER(p)->id, sizeof(uint16_t)); | |
1161 | ||
a4076574 LP |
1162 | DNS_PACKET_HEADER(p)->qdcount = htobe16(1); |
1163 | DNS_PACKET_HEADER(p)->arcount = htobe16(1); | |
1164 | ||
58ab31d5 | 1165 | r = dns_packet_append_key(p, rr->key, 0, NULL); |
a4076574 LP |
1166 | if (r < 0) |
1167 | return r; | |
1168 | ||
58ab31d5 | 1169 | r = dns_packet_append_rr(p, rr, 0, NULL, NULL); |
a4076574 LP |
1170 | if (r < 0) |
1171 | return r; | |
1172 | ||
1cc6c93a | 1173 | *ret = TAKE_PTR(p); |
a4076574 LP |
1174 | |
1175 | return 0; | |
1176 | } | |
1177 | ||
1178 | static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata) { | |
99534007 | 1179 | DnsScope *scope = ASSERT_PTR(userdata); |
a4076574 LP |
1180 | int r; |
1181 | ||
1182 | assert(es); | |
a4076574 | 1183 | |
97935302 | 1184 | scope->conflict_event_source = sd_event_source_disable_unref(scope->conflict_event_source); |
a4076574 LP |
1185 | |
1186 | for (;;) { | |
432d108c | 1187 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; |
a4076574 LP |
1188 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; |
1189 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1190 | ||
432d108c DR |
1191 | key = ordered_hashmap_first_key(scope->conflict_queue); |
1192 | if (!key) | |
a4076574 LP |
1193 | break; |
1194 | ||
432d108c DR |
1195 | rr = ordered_hashmap_remove(scope->conflict_queue, key); |
1196 | assert(rr); | |
1197 | ||
a4076574 LP |
1198 | r = dns_scope_make_conflict_packet(scope, rr, &p); |
1199 | if (r < 0) { | |
da927ba9 | 1200 | log_error_errno(r, "Failed to make conflict packet: %m"); |
a4076574 LP |
1201 | return 0; |
1202 | } | |
1203 | ||
d79677ab | 1204 | r = dns_scope_emit_udp(scope, -1, AF_UNSPEC, p); |
a4076574 | 1205 | if (r < 0) |
da927ba9 | 1206 | log_debug_errno(r, "Failed to send conflict packet: %m"); |
a4076574 LP |
1207 | } |
1208 | ||
1209 | return 0; | |
1210 | } | |
1211 | ||
1212 | int dns_scope_notify_conflict(DnsScope *scope, DnsResourceRecord *rr) { | |
a4076574 LP |
1213 | int r; |
1214 | ||
1215 | assert(scope); | |
1216 | assert(rr); | |
1217 | ||
1218 | /* We don't send these queries immediately. Instead, we queue | |
1219 | * them, and send them after some jitter delay. */ | |
1e43061b | 1220 | r = ordered_hashmap_ensure_allocated(&scope->conflict_queue, &dns_resource_key_hash_ops); |
a4076574 LP |
1221 | if (r < 0) { |
1222 | log_oom(); | |
1223 | return r; | |
1224 | } | |
1225 | ||
1226 | /* We only place one RR per key in the conflict | |
1227 | * messages, not all of them. That should be enough to | |
1228 | * indicate where there might be a conflict */ | |
1e43061b | 1229 | r = ordered_hashmap_put(scope->conflict_queue, rr->key, rr); |
4c701096 | 1230 | if (IN_SET(r, 0, -EEXIST)) |
a4076574 | 1231 | return 0; |
f647962d MS |
1232 | if (r < 0) |
1233 | return log_debug_errno(r, "Failed to queue conflicting RR: %m"); | |
a4076574 | 1234 | |
432d108c | 1235 | dns_resource_key_ref(rr->key); |
a4076574 LP |
1236 | dns_resource_record_ref(rr); |
1237 | ||
1238 | if (scope->conflict_event_source) | |
1239 | return 0; | |
1240 | ||
39cf0351 LP |
1241 | r = sd_event_add_time_relative( |
1242 | scope->manager->event, | |
1243 | &scope->conflict_event_source, | |
ba4e0427 | 1244 | CLOCK_BOOTTIME, |
765647ba YW |
1245 | random_u64_range(LLMNR_JITTER_INTERVAL_USEC), |
1246 | 0, | |
39cf0351 | 1247 | on_conflict_dispatch, scope); |
f647962d MS |
1248 | if (r < 0) |
1249 | return log_debug_errno(r, "Failed to add conflict dispatch event: %m"); | |
a4076574 | 1250 | |
aa4a9deb LP |
1251 | (void) sd_event_source_set_description(scope->conflict_event_source, "scope-conflict"); |
1252 | ||
a4076574 LP |
1253 | return 0; |
1254 | } | |
1255 | ||
1256 | void dns_scope_check_conflicts(DnsScope *scope, DnsPacket *p) { | |
c1227a18 | 1257 | DnsResourceRecord *rr; |
a4076574 LP |
1258 | int r; |
1259 | ||
1260 | assert(scope); | |
1261 | assert(p); | |
1262 | ||
53fda2bb | 1263 | if (!IN_SET(p->protocol, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) |
a4076574 LP |
1264 | return; |
1265 | ||
1266 | if (DNS_PACKET_RRCOUNT(p) <= 0) | |
1267 | return; | |
1268 | ||
53fda2bb DR |
1269 | if (p->protocol == DNS_PROTOCOL_LLMNR) { |
1270 | if (DNS_PACKET_LLMNR_C(p) != 0) | |
1271 | return; | |
a4076574 | 1272 | |
53fda2bb DR |
1273 | if (DNS_PACKET_LLMNR_T(p) != 0) |
1274 | return; | |
1275 | } | |
a4076574 | 1276 | |
94378145 | 1277 | if (manager_packet_from_local_address(scope->manager, p)) |
a4076574 LP |
1278 | return; |
1279 | ||
1280 | r = dns_packet_extract(p); | |
1281 | if (r < 0) { | |
da927ba9 | 1282 | log_debug_errno(r, "Failed to extract packet: %m"); |
a4076574 LP |
1283 | return; |
1284 | } | |
1285 | ||
1286 | log_debug("Checking for conflicts..."); | |
1287 | ||
c1227a18 | 1288 | DNS_ANSWER_FOREACH(rr, p->answer) { |
cfcc8dcc | 1289 | /* No conflict if it is DNS-SD RR used for service enumeration. */ |
c1227a18 | 1290 | if (dns_resource_key_is_dnssd_ptr(rr->key)) |
cfcc8dcc DR |
1291 | continue; |
1292 | ||
a4076574 LP |
1293 | /* Check for conflicts against the local zone. If we |
1294 | * found one, we won't check any further */ | |
c1227a18 | 1295 | r = dns_zone_check_conflicts(&scope->zone, rr); |
a4076574 LP |
1296 | if (r != 0) |
1297 | continue; | |
1298 | ||
1299 | /* Check for conflicts against the local cache. If so, | |
1300 | * send out an advisory query, to inform everybody */ | |
c1227a18 | 1301 | r = dns_cache_check_conflicts(&scope->cache, rr, p->family, &p->sender); |
a4076574 LP |
1302 | if (r <= 0) |
1303 | continue; | |
1304 | ||
c1227a18 | 1305 | dns_scope_notify_conflict(scope, rr); |
a4076574 LP |
1306 | } |
1307 | } | |
4d506d6b LP |
1308 | |
1309 | void dns_scope_dump(DnsScope *s, FILE *f) { | |
1310 | assert(s); | |
1311 | ||
1312 | if (!f) | |
1313 | f = stdout; | |
1314 | ||
1315 | fputs("[Scope protocol=", f); | |
1316 | fputs(dns_protocol_to_string(s->protocol), f); | |
1317 | ||
1318 | if (s->link) { | |
1319 | fputs(" interface=", f); | |
6ff79f76 | 1320 | fputs(s->link->ifname, f); |
4d506d6b LP |
1321 | } |
1322 | ||
1323 | if (s->family != AF_UNSPEC) { | |
1324 | fputs(" family=", f); | |
1325 | fputs(af_to_name(s->family), f); | |
1326 | } | |
1327 | ||
1328 | fputs("]\n", f); | |
1329 | ||
1330 | if (!dns_zone_is_empty(&s->zone)) { | |
1331 | fputs("ZONE:\n", f); | |
1332 | dns_zone_dump(&s->zone, f); | |
1333 | } | |
1334 | ||
1335 | if (!dns_cache_is_empty(&s->cache)) { | |
1336 | fputs("CACHE:\n", f); | |
ca9fab88 | 1337 | dns_cache_dump(&s->cache, f); |
4d506d6b LP |
1338 | } |
1339 | } | |
a51c1048 LP |
1340 | |
1341 | DnsSearchDomain *dns_scope_get_search_domains(DnsScope *s) { | |
801ad6a6 LP |
1342 | assert(s); |
1343 | ||
a51c1048 LP |
1344 | if (s->protocol != DNS_PROTOCOL_DNS) |
1345 | return NULL; | |
1346 | ||
1347 | if (s->link) | |
1348 | return s->link->search_domains; | |
1349 | ||
28b9b764 | 1350 | return s->manager->search_domains; |
801ad6a6 LP |
1351 | } |
1352 | ||
3b5bd7d6 | 1353 | bool dns_scope_name_wants_search_domain(DnsScope *s, const char *name) { |
801ad6a6 LP |
1354 | assert(s); |
1355 | ||
1356 | if (s->protocol != DNS_PROTOCOL_DNS) | |
dc477e73 | 1357 | return false; |
801ad6a6 | 1358 | |
dc477e73 | 1359 | return dns_name_is_single_label(name); |
801ad6a6 | 1360 | } |
edbcc1fd LP |
1361 | |
1362 | bool dns_scope_network_good(DnsScope *s) { | |
edbcc1fd LP |
1363 | /* Checks whether the network is in good state for lookups on this scope. For mDNS/LLMNR/Classic DNS scopes |
1364 | * bound to links this is easy, as they don't even exist if the link isn't in a suitable state. For the global | |
de4a0138 LP |
1365 | * DNS scope we check whether there are any links that are up and have an address. |
1366 | * | |
1367 | * Note that Linux routing is complex and even systems that superficially have no IPv4 address might | |
1368 | * be able to route IPv4 (and similar for IPv6), hence let's make a check here independent of address | |
1369 | * family. */ | |
edbcc1fd LP |
1370 | |
1371 | if (s->link) | |
1372 | return true; | |
1373 | ||
de4a0138 | 1374 | return manager_routable(s->manager); |
edbcc1fd | 1375 | } |
97ebebbc LP |
1376 | |
1377 | int dns_scope_ifindex(DnsScope *s) { | |
1378 | assert(s); | |
1379 | ||
1380 | if (s->link) | |
1381 | return s->link->ifindex; | |
1382 | ||
1383 | return 0; | |
1384 | } | |
53fda2bb DR |
1385 | |
1386 | static int on_announcement_timeout(sd_event_source *s, usec_t usec, void *userdata) { | |
1387 | DnsScope *scope = userdata; | |
1388 | ||
1389 | assert(s); | |
1390 | ||
97935302 | 1391 | scope->announce_event_source = sd_event_source_disable_unref(scope->announce_event_source); |
53fda2bb | 1392 | |
1a63fc54 | 1393 | (void) dns_scope_announce(scope, false); |
53fda2bb DR |
1394 | return 0; |
1395 | } | |
1396 | ||
1a63fc54 | 1397 | int dns_scope_announce(DnsScope *scope, bool goodbye) { |
53fda2bb DR |
1398 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; |
1399 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
a2bf8a19 | 1400 | _cleanup_set_free_ Set *types = NULL; |
03677889 | 1401 | DnsZoneItem *z; |
a2bf8a19 | 1402 | unsigned size = 0; |
a2bf8a19 | 1403 | char *service_type; |
53fda2bb DR |
1404 | int r; |
1405 | ||
1406 | if (!scope) | |
1a63fc54 | 1407 | return 0; |
53fda2bb DR |
1408 | |
1409 | if (scope->protocol != DNS_PROTOCOL_MDNS) | |
1a63fc54 | 1410 | return 0; |
53fda2bb | 1411 | |
a2bf8a19 DR |
1412 | /* Check if we're done with probing. */ |
1413 | LIST_FOREACH(transactions_by_scope, t, scope->transactions) | |
1414 | if (DNS_TRANSACTION_IS_LIVE(t->state)) | |
1415 | return 0; | |
1416 | ||
e7c1b0e4 DR |
1417 | /* Check if there're services pending conflict resolution. */ |
1418 | if (manager_next_dnssd_names(scope->manager)) | |
1419 | return 0; /* we reach this point only if changing hostname didn't help */ | |
1420 | ||
a2bf8a19 | 1421 | /* Calculate answer's size. */ |
90e74a66 | 1422 | HASHMAP_FOREACH(z, scope->zone.by_key) { |
a2bf8a19 DR |
1423 | if (z->state != DNS_ZONE_ITEM_ESTABLISHED) |
1424 | continue; | |
1425 | ||
1426 | if (z->rr->key->type == DNS_TYPE_PTR && | |
1427 | !dns_zone_contains_name(&scope->zone, z->rr->ptr.name)) { | |
1428 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; | |
1429 | ||
1430 | log_debug("Skip PTR RR <%s> since its counterparts seem to be withdrawn", dns_resource_key_to_string(z->rr->key, key_str, sizeof key_str)); | |
1431 | z->state = DNS_ZONE_ITEM_WITHDRAWN; | |
1432 | continue; | |
1433 | } | |
1434 | ||
1435 | /* Collect service types for _services._dns-sd._udp.local RRs in a set */ | |
1436 | if (!scope->announced && | |
1437 | dns_resource_key_is_dnssd_ptr(z->rr->key)) { | |
1438 | if (!set_contains(types, dns_resource_key_name(z->rr->key))) { | |
de7fef4b | 1439 | r = set_ensure_put(&types, &dns_name_hash_ops, dns_resource_key_name(z->rr->key)); |
a2bf8a19 DR |
1440 | if (r < 0) |
1441 | return log_debug_errno(r, "Failed to add item to set: %m"); | |
1442 | } | |
1443 | } | |
1444 | ||
400f54fb DR |
1445 | LIST_FOREACH(by_key, i, z) |
1446 | size++; | |
a2bf8a19 DR |
1447 | } |
1448 | ||
1449 | answer = dns_answer_new(size + set_size(types)); | |
1a63fc54 LP |
1450 | if (!answer) |
1451 | return log_oom(); | |
1452 | ||
a2bf8a19 | 1453 | /* Second iteration, actually add RRs to the answer. */ |
90e74a66 | 1454 | HASHMAP_FOREACH(z, scope->zone.by_key) |
400f54fb DR |
1455 | LIST_FOREACH (by_key, i, z) { |
1456 | DnsAnswerFlags flags; | |
a2bf8a19 | 1457 | |
400f54fb DR |
1458 | if (i->state != DNS_ZONE_ITEM_ESTABLISHED) |
1459 | continue; | |
a2bf8a19 | 1460 | |
400f54fb DR |
1461 | if (dns_resource_key_is_dnssd_ptr(i->rr->key)) |
1462 | flags = goodbye ? DNS_ANSWER_GOODBYE : 0; | |
1463 | else | |
1464 | flags = goodbye ? (DNS_ANSWER_GOODBYE|DNS_ANSWER_CACHE_FLUSH) : DNS_ANSWER_CACHE_FLUSH; | |
a2bf8a19 | 1465 | |
04617bf8 | 1466 | r = dns_answer_add(answer, i->rr, 0, flags, NULL); |
400f54fb DR |
1467 | if (r < 0) |
1468 | return log_debug_errno(r, "Failed to add RR to announce: %m"); | |
1469 | } | |
a2bf8a19 DR |
1470 | |
1471 | /* Since all the active services are in the zone make them discoverable now. */ | |
90e74a66 | 1472 | SET_FOREACH(service_type, types) { |
c2b2df60 | 1473 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; |
a2bf8a19 DR |
1474 | |
1475 | rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_PTR, | |
1476 | "_services._dns-sd._udp.local"); | |
c73f413d FS |
1477 | if (!rr) |
1478 | return log_oom(); | |
7ac29d2d | 1479 | |
a2bf8a19 | 1480 | rr->ptr.name = strdup(service_type); |
7ac29d2d LP |
1481 | if (!rr->ptr.name) |
1482 | return log_oom(); | |
1483 | ||
a2bf8a19 DR |
1484 | rr->ttl = MDNS_DEFAULT_TTL; |
1485 | ||
1486 | r = dns_zone_put(&scope->zone, scope, rr, false); | |
1a63fc54 | 1487 | if (r < 0) |
7ac29d2d | 1488 | log_warning_errno(r, "Failed to add DNS-SD PTR record to MDNS zone, ignoring: %m"); |
1a63fc54 | 1489 | |
04617bf8 | 1490 | r = dns_answer_add(answer, rr, 0, 0, NULL); |
1a63fc54 | 1491 | if (r < 0) |
a2bf8a19 | 1492 | return log_debug_errno(r, "Failed to add RR to announce: %m"); |
53fda2bb DR |
1493 | } |
1494 | ||
1495 | if (dns_answer_isempty(answer)) | |
1a63fc54 | 1496 | return 0; |
53fda2bb DR |
1497 | |
1498 | r = dns_scope_make_reply_packet(scope, 0, DNS_RCODE_SUCCESS, NULL, answer, NULL, false, &p); | |
1a63fc54 LP |
1499 | if (r < 0) |
1500 | return log_debug_errno(r, "Failed to build reply packet: %m"); | |
1501 | ||
d79677ab | 1502 | r = dns_scope_emit_udp(scope, -1, AF_UNSPEC, p); |
1a63fc54 LP |
1503 | if (r < 0) |
1504 | return log_debug_errno(r, "Failed to send reply packet: %m"); | |
53fda2bb DR |
1505 | |
1506 | /* In section 8.3 of RFC6762: "The Multicast DNS responder MUST send at least two unsolicited | |
1507 | * responses, one second apart." */ | |
1508 | if (!scope->announced) { | |
53fda2bb DR |
1509 | scope->announced = true; |
1510 | ||
39cf0351 | 1511 | r = sd_event_add_time_relative( |
53fda2bb DR |
1512 | scope->manager->event, |
1513 | &scope->announce_event_source, | |
ba4e0427 | 1514 | CLOCK_BOOTTIME, |
39cf0351 | 1515 | MDNS_ANNOUNCE_DELAY, |
765647ba | 1516 | 0, |
53fda2bb DR |
1517 | on_announcement_timeout, scope); |
1518 | if (r < 0) | |
1a63fc54 | 1519 | return log_debug_errno(r, "Failed to schedule second announcement: %m"); |
19fee3ef LP |
1520 | |
1521 | (void) sd_event_source_set_description(scope->announce_event_source, "mdns-announce"); | |
53fda2bb | 1522 | } |
1a63fc54 LP |
1523 | |
1524 | return 0; | |
53fda2bb | 1525 | } |
6db6a464 DR |
1526 | |
1527 | int dns_scope_add_dnssd_services(DnsScope *scope) { | |
6db6a464 DR |
1528 | DnssdService *service; |
1529 | int r; | |
1530 | ||
1531 | assert(scope); | |
1532 | ||
1533 | if (hashmap_size(scope->manager->dnssd_services) == 0) | |
1534 | return 0; | |
1535 | ||
1536 | scope->announced = false; | |
1537 | ||
90e74a66 | 1538 | HASHMAP_FOREACH(service, scope->manager->dnssd_services) { |
c3036641 DR |
1539 | service->withdrawn = false; |
1540 | ||
6db6a464 DR |
1541 | r = dns_zone_put(&scope->zone, scope, service->ptr_rr, false); |
1542 | if (r < 0) | |
1543 | log_warning_errno(r, "Failed to add PTR record to MDNS zone: %m"); | |
1544 | ||
1545 | r = dns_zone_put(&scope->zone, scope, service->srv_rr, true); | |
1546 | if (r < 0) | |
1547 | log_warning_errno(r, "Failed to add SRV record to MDNS zone: %m"); | |
1548 | ||
400f54fb DR |
1549 | LIST_FOREACH(items, txt_data, service->txt_data_items) { |
1550 | r = dns_zone_put(&scope->zone, scope, txt_data->rr, true); | |
1551 | if (r < 0) | |
1552 | log_warning_errno(r, "Failed to add TXT record to MDNS zone: %m"); | |
1553 | } | |
6db6a464 DR |
1554 | } |
1555 | ||
1556 | return 0; | |
1557 | } | |
1558 | ||
1559 | int dns_scope_remove_dnssd_services(DnsScope *scope) { | |
1560 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; | |
6db6a464 DR |
1561 | DnssdService *service; |
1562 | int r; | |
1563 | ||
1564 | assert(scope); | |
1565 | ||
1566 | key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_PTR, | |
1567 | "_services._dns-sd._udp.local"); | |
1568 | if (!key) | |
1569 | return log_oom(); | |
1570 | ||
1571 | r = dns_zone_remove_rrs_by_key(&scope->zone, key); | |
1572 | if (r < 0) | |
1573 | return r; | |
1574 | ||
90e74a66 | 1575 | HASHMAP_FOREACH(service, scope->manager->dnssd_services) { |
6db6a464 DR |
1576 | dns_zone_remove_rr(&scope->zone, service->ptr_rr); |
1577 | dns_zone_remove_rr(&scope->zone, service->srv_rr); | |
400f54fb DR |
1578 | LIST_FOREACH(items, txt_data, service->txt_data_items) |
1579 | dns_zone_remove_rr(&scope->zone, txt_data->rr); | |
6db6a464 DR |
1580 | } |
1581 | ||
1582 | return 0; | |
1583 | } | |
f76fa088 | 1584 | |
ca5394d2 | 1585 | static bool dns_scope_has_route_only_domains(DnsScope *scope) { |
03677889 | 1586 | DnsSearchDomain *first; |
f76fa088 LP |
1587 | bool route_only = false; |
1588 | ||
ca5394d2 LP |
1589 | assert(scope); |
1590 | assert(scope->protocol == DNS_PROTOCOL_DNS); | |
f76fa088 | 1591 | |
ca5394d2 LP |
1592 | /* Returns 'true' if this scope is suitable for queries to specific domains only. For that we check |
1593 | * if there are any route-only domains on this interface, as a heuristic to discern VPN-style links | |
1594 | * from non-VPN-style links. Returns 'false' for all other cases, i.e. if the scope is intended to | |
1595 | * take queries to arbitrary domains, i.e. has no routing domains set. */ | |
f76fa088 LP |
1596 | |
1597 | if (scope->link) | |
1598 | first = scope->link->search_domains; | |
1599 | else | |
1600 | first = scope->manager->search_domains; | |
1601 | ||
1602 | LIST_FOREACH(domains, domain, first) { | |
ca5394d2 LP |
1603 | /* "." means "any domain", thus the interface takes any kind of traffic. Thus, we exit early |
1604 | * here, as it doesn't really matter whether this link has any route-only domains or not, | |
1605 | * "~." really trumps everything and clearly indicates that this interface shall receive all | |
1606 | * traffic it can get. */ | |
f76fa088 LP |
1607 | if (dns_name_is_root(DNS_SEARCH_DOMAIN_NAME(domain))) |
1608 | return false; | |
1609 | ||
1610 | if (domain->route_only) | |
1611 | route_only = true; | |
1612 | } | |
1613 | ||
1614 | return route_only; | |
1615 | } | |
ca5394d2 LP |
1616 | |
1617 | bool dns_scope_is_default_route(DnsScope *scope) { | |
1618 | assert(scope); | |
1619 | ||
1620 | /* Only use DNS scopes as default routes */ | |
1621 | if (scope->protocol != DNS_PROTOCOL_DNS) | |
1622 | return false; | |
1623 | ||
1624 | /* The global DNS scope is always suitable as default route */ | |
1625 | if (!scope->link) | |
1626 | return true; | |
1627 | ||
1628 | /* Honour whatever is explicitly configured. This is really the best approach, and trumps any | |
1629 | * automatic logic. */ | |
1630 | if (scope->link->default_route >= 0) | |
1631 | return scope->link->default_route; | |
1632 | ||
1633 | /* Otherwise check if we have any route-only domains, as a sensible heuristic: if so, let's not | |
1634 | * volunteer as default route. */ | |
1635 | return !dns_scope_has_route_only_domains(scope); | |
1636 | } |