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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ | |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 Tom Gundersen <teg@jklm.no> | |
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 | ||
22 | #include <netinet/in.h> | |
23 | #include <resolv.h> | |
24 | ||
25 | #include "fd-util.h" | |
26 | #include "resolved-llmnr.h" | |
27 | #include "resolved-manager.h" | |
28 | ||
29 | void manager_llmnr_stop(Manager *m) { | |
30 | assert(m); | |
31 | ||
32 | m->llmnr_ipv4_udp_event_source = sd_event_source_unref(m->llmnr_ipv4_udp_event_source); | |
33 | m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd); | |
34 | ||
35 | m->llmnr_ipv6_udp_event_source = sd_event_source_unref(m->llmnr_ipv6_udp_event_source); | |
36 | m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd); | |
37 | ||
38 | m->llmnr_ipv4_tcp_event_source = sd_event_source_unref(m->llmnr_ipv4_tcp_event_source); | |
39 | m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd); | |
40 | ||
41 | m->llmnr_ipv6_tcp_event_source = sd_event_source_unref(m->llmnr_ipv6_tcp_event_source); | |
42 | m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd); | |
43 | } | |
44 | ||
45 | int manager_llmnr_start(Manager *m) { | |
46 | int r; | |
47 | ||
48 | assert(m); | |
49 | ||
50 | if (m->llmnr_support == SUPPORT_NO) | |
51 | return 0; | |
52 | ||
53 | r = manager_llmnr_ipv4_udp_fd(m); | |
54 | if (r == -EADDRINUSE) | |
55 | goto eaddrinuse; | |
56 | if (r < 0) | |
57 | return r; | |
58 | ||
59 | r = manager_llmnr_ipv4_tcp_fd(m); | |
60 | if (r == -EADDRINUSE) | |
61 | goto eaddrinuse; | |
62 | if (r < 0) | |
63 | return r; | |
64 | ||
65 | if (socket_ipv6_is_supported()) { | |
66 | r = manager_llmnr_ipv6_udp_fd(m); | |
67 | if (r == -EADDRINUSE) | |
68 | goto eaddrinuse; | |
69 | if (r < 0) | |
70 | return r; | |
71 | ||
72 | r = manager_llmnr_ipv6_tcp_fd(m); | |
73 | if (r == -EADDRINUSE) | |
74 | goto eaddrinuse; | |
75 | if (r < 0) | |
76 | return r; | |
77 | } | |
78 | ||
79 | return 0; | |
80 | ||
81 | eaddrinuse: | |
82 | log_warning("There appears to be another LLMNR responder running. Turning off LLMNR support."); | |
83 | m->llmnr_support = SUPPORT_NO; | |
84 | manager_llmnr_stop(m); | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
89 | static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
90 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
91 | DnsTransaction *t = NULL; | |
92 | Manager *m = userdata; | |
93 | DnsScope *scope; | |
94 | int r; | |
95 | ||
96 | r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p); | |
97 | if (r <= 0) | |
98 | return r; | |
99 | ||
100 | scope = manager_find_scope(m, p); | |
101 | if (!scope) { | |
102 | log_warning("Got LLMNR UDP packet on unknown scope. Ignoring."); | |
103 | return 0; | |
104 | } | |
105 | ||
106 | if (dns_packet_validate_reply(p) > 0) { | |
107 | log_debug("Got LLMNR reply packet for id %u", DNS_PACKET_ID(p)); | |
108 | ||
109 | dns_scope_check_conflicts(scope, p); | |
110 | ||
111 | t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); | |
112 | if (t) | |
113 | dns_transaction_process_reply(t, p); | |
114 | ||
115 | } else if (dns_packet_validate_query(p) > 0) { | |
116 | log_debug("Got LLMNR query packet for id %u", DNS_PACKET_ID(p)); | |
117 | ||
118 | dns_scope_process_query(scope, NULL, p); | |
119 | } else | |
120 | log_debug("Invalid LLMNR UDP packet."); | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | int manager_llmnr_ipv4_udp_fd(Manager *m) { | |
126 | union sockaddr_union sa = { | |
127 | .in.sin_family = AF_INET, | |
128 | .in.sin_port = htobe16(LLMNR_PORT), | |
129 | }; | |
130 | static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255; | |
131 | int r; | |
132 | ||
133 | assert(m); | |
134 | ||
135 | if (m->llmnr_ipv4_udp_fd >= 0) | |
136 | return m->llmnr_ipv4_udp_fd; | |
137 | ||
138 | m->llmnr_ipv4_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); | |
139 | if (m->llmnr_ipv4_udp_fd < 0) | |
140 | return -errno; | |
141 | ||
142 | /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ | |
143 | r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)); | |
144 | if (r < 0) { | |
145 | r = -errno; | |
146 | goto fail; | |
147 | } | |
148 | ||
149 | r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); | |
150 | if (r < 0) { | |
151 | r = -errno; | |
152 | goto fail; | |
153 | } | |
154 | ||
155 | r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one)); | |
156 | if (r < 0) { | |
157 | r = -errno; | |
158 | goto fail; | |
159 | } | |
160 | ||
161 | r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); | |
162 | if (r < 0) { | |
163 | r = -errno; | |
164 | goto fail; | |
165 | } | |
166 | ||
167 | r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); | |
168 | if (r < 0) { | |
169 | r = -errno; | |
170 | goto fail; | |
171 | } | |
172 | ||
173 | r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); | |
174 | if (r < 0) { | |
175 | r = -errno; | |
176 | goto fail; | |
177 | } | |
178 | ||
179 | /* Disable Don't-Fragment bit in the IP header */ | |
180 | r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); | |
181 | if (r < 0) { | |
182 | r = -errno; | |
183 | goto fail; | |
184 | } | |
185 | ||
186 | r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in)); | |
187 | if (r < 0) { | |
188 | r = -errno; | |
189 | goto fail; | |
190 | } | |
191 | ||
192 | r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m); | |
193 | if (r < 0) | |
194 | goto fail; | |
195 | ||
196 | return m->llmnr_ipv4_udp_fd; | |
197 | ||
198 | fail: | |
199 | m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd); | |
200 | return r; | |
201 | } | |
202 | ||
203 | int manager_llmnr_ipv6_udp_fd(Manager *m) { | |
204 | union sockaddr_union sa = { | |
205 | .in6.sin6_family = AF_INET6, | |
206 | .in6.sin6_port = htobe16(LLMNR_PORT), | |
207 | }; | |
208 | static const int one = 1, ttl = 255; | |
209 | int r; | |
210 | ||
211 | assert(m); | |
212 | ||
213 | if (m->llmnr_ipv6_udp_fd >= 0) | |
214 | return m->llmnr_ipv6_udp_fd; | |
215 | ||
216 | m->llmnr_ipv6_udp_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); | |
217 | if (m->llmnr_ipv6_udp_fd < 0) | |
218 | return -errno; | |
219 | ||
220 | r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl)); | |
221 | if (r < 0) { | |
222 | r = -errno; | |
223 | goto fail; | |
224 | } | |
225 | ||
226 | /* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */ | |
227 | r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)); | |
228 | if (r < 0) { | |
229 | r = -errno; | |
230 | goto fail; | |
231 | } | |
232 | ||
233 | r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one)); | |
234 | if (r < 0) { | |
235 | r = -errno; | |
236 | goto fail; | |
237 | } | |
238 | ||
239 | r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); | |
240 | if (r < 0) { | |
241 | r = -errno; | |
242 | goto fail; | |
243 | } | |
244 | ||
245 | r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); | |
246 | if (r < 0) { | |
247 | r = -errno; | |
248 | goto fail; | |
249 | } | |
250 | ||
251 | r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); | |
252 | if (r < 0) { | |
253 | r = -errno; | |
254 | goto fail; | |
255 | } | |
256 | ||
257 | r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); | |
258 | if (r < 0) { | |
259 | r = -errno; | |
260 | goto fail; | |
261 | } | |
262 | ||
263 | r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6)); | |
264 | if (r < 0) { | |
265 | r = -errno; | |
266 | goto fail; | |
267 | } | |
268 | ||
269 | r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m); | |
270 | if (r < 0) { | |
271 | r = -errno; | |
272 | goto fail; | |
273 | } | |
274 | ||
275 | return m->llmnr_ipv6_udp_fd; | |
276 | ||
277 | fail: | |
278 | m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd); | |
279 | return r; | |
280 | } | |
281 | ||
282 | static int on_llmnr_stream_packet(DnsStream *s) { | |
283 | DnsScope *scope; | |
284 | ||
285 | assert(s); | |
286 | ||
287 | scope = manager_find_scope(s->manager, s->read_packet); | |
288 | if (!scope) { | |
289 | log_warning("Got LLMNR TCP packet on unknown scope. Ignroing."); | |
290 | return 0; | |
291 | } | |
292 | ||
293 | if (dns_packet_validate_query(s->read_packet) > 0) { | |
294 | log_debug("Got query packet for id %u", DNS_PACKET_ID(s->read_packet)); | |
295 | ||
296 | dns_scope_process_query(scope, s, s->read_packet); | |
297 | ||
298 | /* If no reply packet was set, we free the stream */ | |
299 | if (s->write_packet) | |
300 | return 0; | |
301 | } else | |
302 | log_debug("Invalid LLMNR TCP packet."); | |
303 | ||
304 | dns_stream_free(s); | |
305 | return 0; | |
306 | } | |
307 | ||
308 | static int on_llmnr_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
309 | DnsStream *stream; | |
310 | Manager *m = userdata; | |
311 | int cfd, r; | |
312 | ||
313 | cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); | |
314 | if (cfd < 0) { | |
315 | if (errno == EAGAIN || errno == EINTR) | |
316 | return 0; | |
317 | ||
318 | return -errno; | |
319 | } | |
320 | ||
321 | r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd); | |
322 | if (r < 0) { | |
323 | safe_close(cfd); | |
324 | return r; | |
325 | } | |
326 | ||
327 | stream->on_packet = on_llmnr_stream_packet; | |
328 | return 0; | |
329 | } | |
330 | ||
331 | int manager_llmnr_ipv4_tcp_fd(Manager *m) { | |
332 | union sockaddr_union sa = { | |
333 | .in.sin_family = AF_INET, | |
334 | .in.sin_port = htobe16(LLMNR_PORT), | |
335 | }; | |
336 | static const int one = 1, pmtu = IP_PMTUDISC_DONT; | |
337 | int r; | |
338 | ||
339 | assert(m); | |
340 | ||
341 | if (m->llmnr_ipv4_tcp_fd >= 0) | |
342 | return m->llmnr_ipv4_tcp_fd; | |
343 | ||
344 | m->llmnr_ipv4_tcp_fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); | |
345 | if (m->llmnr_ipv4_tcp_fd < 0) | |
346 | return -errno; | |
347 | ||
348 | /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */ | |
349 | r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); | |
350 | if (r < 0) { | |
351 | r = -errno; | |
352 | goto fail; | |
353 | } | |
354 | ||
355 | r = setsockopt(m->llmnr_ipv4_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); | |
356 | if (r < 0) { | |
357 | r = -errno; | |
358 | goto fail; | |
359 | } | |
360 | ||
361 | r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); | |
362 | if (r < 0) { | |
363 | r = -errno; | |
364 | goto fail; | |
365 | } | |
366 | ||
367 | r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); | |
368 | if (r < 0) { | |
369 | r = -errno; | |
370 | goto fail; | |
371 | } | |
372 | ||
373 | /* Disable Don't-Fragment bit in the IP header */ | |
374 | r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); | |
375 | if (r < 0) { | |
376 | r = -errno; | |
377 | goto fail; | |
378 | } | |
379 | ||
380 | r = bind(m->llmnr_ipv4_tcp_fd, &sa.sa, sizeof(sa.in)); | |
381 | if (r < 0) { | |
382 | r = -errno; | |
383 | goto fail; | |
384 | } | |
385 | ||
386 | r = listen(m->llmnr_ipv4_tcp_fd, SOMAXCONN); | |
387 | if (r < 0) { | |
388 | r = -errno; | |
389 | goto fail; | |
390 | } | |
391 | ||
392 | r = sd_event_add_io(m->event, &m->llmnr_ipv4_tcp_event_source, m->llmnr_ipv4_tcp_fd, EPOLLIN, on_llmnr_stream, m); | |
393 | if (r < 0) | |
394 | goto fail; | |
395 | ||
396 | return m->llmnr_ipv4_tcp_fd; | |
397 | ||
398 | fail: | |
399 | m->llmnr_ipv4_tcp_fd = safe_close(m->llmnr_ipv4_tcp_fd); | |
400 | return r; | |
401 | } | |
402 | ||
403 | int manager_llmnr_ipv6_tcp_fd(Manager *m) { | |
404 | union sockaddr_union sa = { | |
405 | .in6.sin6_family = AF_INET6, | |
406 | .in6.sin6_port = htobe16(LLMNR_PORT), | |
407 | }; | |
408 | static const int one = 1; | |
409 | int r; | |
410 | ||
411 | assert(m); | |
412 | ||
413 | if (m->llmnr_ipv6_tcp_fd >= 0) | |
414 | return m->llmnr_ipv6_tcp_fd; | |
415 | ||
416 | m->llmnr_ipv6_tcp_fd = socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); | |
417 | if (m->llmnr_ipv6_tcp_fd < 0) | |
418 | return -errno; | |
419 | ||
420 | /* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */ | |
421 | r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); | |
422 | if (r < 0) { | |
423 | r = -errno; | |
424 | goto fail; | |
425 | } | |
426 | ||
427 | r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); | |
428 | if (r < 0) { | |
429 | r = -errno; | |
430 | goto fail; | |
431 | } | |
432 | ||
433 | r = setsockopt(m->llmnr_ipv6_tcp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); | |
434 | if (r < 0) { | |
435 | r = -errno; | |
436 | goto fail; | |
437 | } | |
438 | ||
439 | r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); | |
440 | if (r < 0) { | |
441 | r = -errno; | |
442 | goto fail; | |
443 | } | |
444 | ||
445 | r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); | |
446 | if (r < 0) { | |
447 | r = -errno; | |
448 | goto fail; | |
449 | } | |
450 | ||
451 | r = bind(m->llmnr_ipv6_tcp_fd, &sa.sa, sizeof(sa.in6)); | |
452 | if (r < 0) { | |
453 | r = -errno; | |
454 | goto fail; | |
455 | } | |
456 | ||
457 | r = listen(m->llmnr_ipv6_tcp_fd, SOMAXCONN); | |
458 | if (r < 0) { | |
459 | r = -errno; | |
460 | goto fail; | |
461 | } | |
462 | ||
463 | r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m); | |
464 | if (r < 0) { | |
465 | r = -errno; | |
466 | goto fail; | |
467 | } | |
468 | ||
469 | return m->llmnr_ipv6_tcp_fd; | |
470 | ||
471 | fail: | |
472 | m->llmnr_ipv6_tcp_fd = safe_close(m->llmnr_ipv6_tcp_fd); | |
473 | return r; | |
474 | } |