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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
b30bf55d LP |
2 | |
3 | #include "fd-util.h" | |
ef118d00 | 4 | #include "missing_network.h" |
b30bf55d LP |
5 | #include "resolved-dns-stub.h" |
6 | #include "socket-util.h" | |
7 | ||
8 | /* The MTU of the loopback device is 64K on Linux, advertise that as maximum datagram size, but subtract the Ethernet, | |
9 | * IP and UDP header sizes */ | |
10 | #define ADVERTISE_DATAGRAM_SIZE_MAX (65536U-14U-20U-8U) | |
11 | ||
424e490b ZJS |
12 | static int manager_dns_stub_udp_fd(Manager *m); |
13 | static int manager_dns_stub_tcp_fd(Manager *m); | |
14 | ||
b30bf55d | 15 | static int dns_stub_make_reply_packet( |
e8d23f92 | 16 | DnsPacket **p, |
51027656 | 17 | size_t max_size, |
b30bf55d | 18 | DnsQuestion *q, |
51027656 LP |
19 | DnsAnswer *answer, |
20 | bool *ret_truncated) { | |
b30bf55d | 21 | |
51027656 | 22 | bool truncated = false; |
b30bf55d LP |
23 | DnsResourceRecord *rr; |
24 | unsigned c = 0; | |
25 | int r; | |
26 | ||
e8d23f92 LP |
27 | assert(p); |
28 | ||
b30bf55d LP |
29 | /* Note that we don't bother with any additional RRs, as this is stub is for local lookups only, and hence |
30 | * roundtrips aren't expensive. */ | |
31 | ||
e8d23f92 | 32 | if (!*p) { |
51027656 | 33 | r = dns_packet_new(p, DNS_PROTOCOL_DNS, 0, max_size); |
e8d23f92 LP |
34 | if (r < 0) |
35 | return r; | |
b30bf55d | 36 | |
e8d23f92 LP |
37 | r = dns_packet_append_question(*p, q); |
38 | if (r < 0) | |
39 | return r; | |
b30bf55d | 40 | |
e8d23f92 LP |
41 | DNS_PACKET_HEADER(*p)->qdcount = htobe16(dns_question_size(q)); |
42 | } | |
b30bf55d LP |
43 | |
44 | DNS_ANSWER_FOREACH(rr, answer) { | |
e8d23f92 | 45 | |
b30bf55d LP |
46 | r = dns_question_matches_rr(q, rr, NULL); |
47 | if (r < 0) | |
48 | return r; | |
49 | if (r > 0) | |
50 | goto add; | |
51 | ||
52 | r = dns_question_matches_cname_or_dname(q, rr, NULL); | |
53 | if (r < 0) | |
54 | return r; | |
55 | if (r > 0) | |
56 | goto add; | |
57 | ||
58 | continue; | |
59 | add: | |
01c901e2 | 60 | r = dns_packet_append_rr(*p, rr, 0, NULL, NULL); |
51027656 LP |
61 | if (r == -EMSGSIZE) { |
62 | truncated = true; | |
63 | break; | |
64 | } | |
b30bf55d LP |
65 | if (r < 0) |
66 | return r; | |
67 | ||
68 | c++; | |
69 | } | |
e8d23f92 | 70 | |
51027656 LP |
71 | if (ret_truncated) |
72 | *ret_truncated = truncated; | |
73 | else if (truncated) | |
74 | return -EMSGSIZE; | |
75 | ||
e8d23f92 LP |
76 | DNS_PACKET_HEADER(*p)->ancount = htobe16(be16toh(DNS_PACKET_HEADER(*p)->ancount) + c); |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | static int dns_stub_finish_reply_packet( | |
82 | DnsPacket *p, | |
83 | uint16_t id, | |
84 | int rcode, | |
51027656 | 85 | bool tc, /* set the Truncated bit? */ |
e8d23f92 LP |
86 | bool add_opt, /* add an OPT RR to this packet? */ |
87 | bool edns0_do, /* set the EDNS0 DNSSEC OK bit? */ | |
88 | bool ad) { /* set the DNSSEC authenticated data bit? */ | |
89 | ||
90 | int r; | |
91 | ||
92 | assert(p); | |
93 | ||
941dd294 LP |
94 | if (!add_opt) { |
95 | /* If the client can't to EDNS0, don't do DO either */ | |
96 | edns0_do = false; | |
97 | ||
98 | /* If the client didn't do EDNS, clamp the rcode to 4 bit */ | |
99 | if (rcode > 0xF) | |
100 | rcode = DNS_RCODE_SERVFAIL; | |
101 | } | |
102 | ||
103 | /* Don't set the AD bit unless DO is on, too */ | |
104 | if (!edns0_do) | |
105 | ad = false; | |
e8d23f92 LP |
106 | |
107 | DNS_PACKET_HEADER(p)->id = id; | |
108 | ||
109 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( | |
51027656 LP |
110 | 1 /* qr */, |
111 | 0 /* opcode */, | |
112 | 0 /* aa */, | |
113 | tc /* tc */, | |
114 | 1 /* rd */, | |
115 | 1 /* ra */, | |
e8d23f92 | 116 | ad /* ad */, |
51027656 | 117 | 0 /* cd */, |
e8d23f92 | 118 | rcode)); |
b30bf55d LP |
119 | |
120 | if (add_opt) { | |
121 | r = dns_packet_append_opt(p, ADVERTISE_DATAGRAM_SIZE_MAX, edns0_do, rcode, NULL); | |
122 | if (r < 0) | |
123 | return r; | |
124 | } | |
125 | ||
b30bf55d LP |
126 | return 0; |
127 | } | |
128 | ||
129 | static void dns_stub_detach_stream(DnsStream *s) { | |
130 | assert(s); | |
131 | ||
132 | s->complete = NULL; | |
133 | s->on_packet = NULL; | |
134 | s->query = NULL; | |
135 | } | |
136 | ||
137 | static int dns_stub_send(Manager *m, DnsStream *s, DnsPacket *p, DnsPacket *reply) { | |
138 | int r; | |
139 | ||
140 | assert(m); | |
141 | assert(p); | |
142 | assert(reply); | |
143 | ||
144 | if (s) | |
145 | r = dns_stream_write_packet(s, reply); | |
146 | else { | |
147 | int fd; | |
148 | ||
b30bf55d LP |
149 | fd = manager_dns_stub_udp_fd(m); |
150 | if (fd < 0) | |
151 | return log_debug_errno(fd, "Failed to get reply socket: %m"); | |
152 | ||
153 | /* Note that it is essential here that we explicitly choose the source IP address for this packet. This | |
154 | * is because otherwise the kernel will choose it automatically based on the routing table and will | |
155 | * thus pick 127.0.0.1 rather than 127.0.0.53. */ | |
156 | ||
157 | r = manager_send(m, fd, LOOPBACK_IFINDEX, p->family, &p->sender, p->sender_port, &p->destination, reply); | |
158 | } | |
159 | if (r < 0) | |
160 | return log_debug_errno(r, "Failed to send reply packet: %m"); | |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
2b2d98c1 | 165 | static int dns_stub_send_failure(Manager *m, DnsStream *s, DnsPacket *p, int rcode, bool authenticated) { |
b30bf55d LP |
166 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; |
167 | int r; | |
168 | ||
169 | assert(m); | |
170 | assert(p); | |
171 | ||
51027656 | 172 | r = dns_stub_make_reply_packet(&reply, DNS_PACKET_PAYLOAD_SIZE_MAX(p), p->question, NULL, NULL); |
e8d23f92 LP |
173 | if (r < 0) |
174 | return log_debug_errno(r, "Failed to make failure packet: %m"); | |
175 | ||
51027656 | 176 | r = dns_stub_finish_reply_packet(reply, DNS_PACKET_ID(p), rcode, false, !!p->opt, DNS_PACKET_DO(p), authenticated); |
b30bf55d LP |
177 | if (r < 0) |
178 | return log_debug_errno(r, "Failed to build failure packet: %m"); | |
179 | ||
180 | return dns_stub_send(m, s, p, reply); | |
181 | } | |
182 | ||
183 | static void dns_stub_query_complete(DnsQuery *q) { | |
184 | int r; | |
185 | ||
186 | assert(q); | |
187 | assert(q->request_dns_packet); | |
188 | ||
189 | switch (q->state) { | |
190 | ||
51027656 LP |
191 | case DNS_TRANSACTION_SUCCESS: { |
192 | bool truncated; | |
e8d23f92 | 193 | |
51027656 | 194 | r = dns_stub_make_reply_packet(&q->reply_dns_packet, DNS_PACKET_PAYLOAD_SIZE_MAX(q->request_dns_packet), q->question_idna, q->answer, &truncated); |
e8d23f92 LP |
195 | if (r < 0) { |
196 | log_debug_errno(r, "Failed to build reply packet: %m"); | |
197 | break; | |
198 | } | |
b30bf55d | 199 | |
e8d23f92 LP |
200 | r = dns_query_process_cname(q); |
201 | if (r == -ELOOP) { | |
2b2d98c1 | 202 | (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_SERVFAIL, false); |
e8d23f92 LP |
203 | break; |
204 | } | |
205 | if (r < 0) { | |
206 | log_debug_errno(r, "Failed to process CNAME: %m"); | |
207 | break; | |
208 | } | |
209 | if (r == DNS_QUERY_RESTARTED) | |
210 | return; | |
211 | ||
212 | r = dns_stub_finish_reply_packet( | |
213 | q->reply_dns_packet, | |
b30bf55d LP |
214 | DNS_PACKET_ID(q->request_dns_packet), |
215 | q->answer_rcode, | |
51027656 | 216 | truncated, |
b30bf55d LP |
217 | !!q->request_dns_packet->opt, |
218 | DNS_PACKET_DO(q->request_dns_packet), | |
941dd294 | 219 | dns_query_fully_authenticated(q)); |
b30bf55d | 220 | if (r < 0) { |
e8d23f92 | 221 | log_debug_errno(r, "Failed to finish reply packet: %m"); |
b30bf55d LP |
222 | break; |
223 | } | |
224 | ||
e8d23f92 | 225 | (void) dns_stub_send(q->manager, q->request_dns_stream, q->request_dns_packet, q->reply_dns_packet); |
b30bf55d | 226 | break; |
51027656 | 227 | } |
b30bf55d LP |
228 | |
229 | case DNS_TRANSACTION_RCODE_FAILURE: | |
2b2d98c1 | 230 | (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, q->answer_rcode, dns_query_fully_authenticated(q)); |
b30bf55d LP |
231 | break; |
232 | ||
233 | case DNS_TRANSACTION_NOT_FOUND: | |
2b2d98c1 | 234 | (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_NXDOMAIN, dns_query_fully_authenticated(q)); |
b30bf55d LP |
235 | break; |
236 | ||
237 | case DNS_TRANSACTION_TIMEOUT: | |
238 | case DNS_TRANSACTION_ATTEMPTS_MAX_REACHED: | |
239 | /* Propagate a timeout as a no packet, i.e. that the client also gets a timeout */ | |
240 | break; | |
241 | ||
242 | case DNS_TRANSACTION_NO_SERVERS: | |
243 | case DNS_TRANSACTION_INVALID_REPLY: | |
244 | case DNS_TRANSACTION_ERRNO: | |
245 | case DNS_TRANSACTION_ABORTED: | |
246 | case DNS_TRANSACTION_DNSSEC_FAILED: | |
247 | case DNS_TRANSACTION_NO_TRUST_ANCHOR: | |
248 | case DNS_TRANSACTION_RR_TYPE_UNSUPPORTED: | |
249 | case DNS_TRANSACTION_NETWORK_DOWN: | |
2b2d98c1 | 250 | (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_SERVFAIL, false); |
b30bf55d LP |
251 | break; |
252 | ||
253 | case DNS_TRANSACTION_NULL: | |
254 | case DNS_TRANSACTION_PENDING: | |
255 | case DNS_TRANSACTION_VALIDATING: | |
256 | default: | |
257 | assert_not_reached("Impossible state"); | |
258 | } | |
259 | ||
260 | /* If there's a packet to write set, let's leave the stream around */ | |
261 | if (q->request_dns_stream && DNS_STREAM_QUEUED(q->request_dns_stream)) { | |
262 | ||
263 | /* Detach the stream from our query (make it an orphan), but do not drop the reference to it. The | |
264 | * default completion action of the stream will drop the reference. */ | |
265 | ||
266 | dns_stub_detach_stream(q->request_dns_stream); | |
267 | q->request_dns_stream = NULL; | |
268 | } | |
269 | ||
270 | dns_query_free(q); | |
271 | } | |
272 | ||
273 | static int dns_stub_stream_complete(DnsStream *s, int error) { | |
274 | assert(s); | |
275 | ||
276 | log_debug_errno(error, "DNS TCP connection terminated, destroying query: %m"); | |
277 | ||
278 | assert(s->query); | |
279 | dns_query_free(s->query); | |
280 | ||
281 | return 0; | |
282 | } | |
283 | ||
284 | static void dns_stub_process_query(Manager *m, DnsStream *s, DnsPacket *p) { | |
285 | DnsQuery *q = NULL; | |
286 | int r; | |
287 | ||
288 | assert(m); | |
289 | assert(p); | |
290 | assert(p->protocol == DNS_PROTOCOL_DNS); | |
291 | ||
292 | /* Takes ownership of the *s stream object */ | |
293 | ||
294 | if (in_addr_is_localhost(p->family, &p->sender) <= 0 || | |
295 | in_addr_is_localhost(p->family, &p->destination) <= 0) { | |
296 | log_error("Got packet on unexpected IP range, refusing."); | |
2b2d98c1 | 297 | dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false); |
b30bf55d LP |
298 | goto fail; |
299 | } | |
300 | ||
301 | r = dns_packet_extract(p); | |
302 | if (r < 0) { | |
303 | log_debug_errno(r, "Failed to extract resources from incoming packet, ignoring packet: %m"); | |
2b2d98c1 | 304 | dns_stub_send_failure(m, s, p, DNS_RCODE_FORMERR, false); |
b30bf55d LP |
305 | goto fail; |
306 | } | |
307 | ||
308 | if (!DNS_PACKET_VERSION_SUPPORTED(p)) { | |
309 | log_debug("Got EDNS OPT field with unsupported version number."); | |
2b2d98c1 | 310 | dns_stub_send_failure(m, s, p, DNS_RCODE_BADVERS, false); |
b30bf55d LP |
311 | goto fail; |
312 | } | |
313 | ||
314 | if (dns_type_is_obsolete(p->question->keys[0]->type)) { | |
315 | log_debug("Got message with obsolete key type, refusing."); | |
2b2d98c1 | 316 | dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false); |
b30bf55d LP |
317 | goto fail; |
318 | } | |
319 | ||
320 | if (dns_type_is_zone_transer(p->question->keys[0]->type)) { | |
321 | log_debug("Got request for zone transfer, refusing."); | |
2b2d98c1 | 322 | dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false); |
b30bf55d LP |
323 | goto fail; |
324 | } | |
325 | ||
326 | if (!DNS_PACKET_RD(p)) { | |
327 | /* If the "rd" bit is off (i.e. recursion was not requested), then refuse operation */ | |
328 | log_debug("Got request with recursion disabled, refusing."); | |
2b2d98c1 | 329 | dns_stub_send_failure(m, s, p, DNS_RCODE_REFUSED, false); |
b30bf55d LP |
330 | goto fail; |
331 | } | |
332 | ||
333 | if (DNS_PACKET_DO(p) && DNS_PACKET_CD(p)) { | |
334 | log_debug("Got request with DNSSEC CD bit set, refusing."); | |
2b2d98c1 | 335 | dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false); |
b30bf55d LP |
336 | goto fail; |
337 | } | |
338 | ||
e8d23f92 | 339 | r = dns_query_new(m, &q, p->question, p->question, 0, SD_RESOLVED_PROTOCOLS_ALL|SD_RESOLVED_NO_SEARCH); |
b30bf55d LP |
340 | if (r < 0) { |
341 | log_error_errno(r, "Failed to generate query object: %m"); | |
2b2d98c1 | 342 | dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false); |
b30bf55d LP |
343 | goto fail; |
344 | } | |
345 | ||
346 | /* Request that the TTL is corrected by the cached time for this lookup, so that we return vaguely useful TTLs */ | |
347 | q->clamp_ttl = true; | |
348 | ||
349 | q->request_dns_packet = dns_packet_ref(p); | |
350 | q->request_dns_stream = dns_stream_ref(s); /* make sure the stream stays around until we can send a reply through it */ | |
351 | q->complete = dns_stub_query_complete; | |
352 | ||
353 | if (s) { | |
354 | s->on_packet = NULL; | |
355 | s->complete = dns_stub_stream_complete; | |
356 | s->query = q; | |
357 | } | |
358 | ||
359 | r = dns_query_go(q); | |
360 | if (r < 0) { | |
361 | log_error_errno(r, "Failed to start query: %m"); | |
2b2d98c1 | 362 | dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false); |
b30bf55d LP |
363 | goto fail; |
364 | } | |
365 | ||
52e63427 | 366 | log_debug("Processing query..."); |
b30bf55d LP |
367 | return; |
368 | ||
369 | fail: | |
370 | if (s && DNS_STREAM_QUEUED(s)) | |
371 | dns_stub_detach_stream(s); | |
372 | ||
373 | dns_query_free(q); | |
374 | } | |
375 | ||
376 | static int on_dns_stub_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
377 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
378 | Manager *m = userdata; | |
379 | int r; | |
380 | ||
381 | r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p); | |
382 | if (r <= 0) | |
383 | return r; | |
384 | ||
385 | if (dns_packet_validate_query(p) > 0) { | |
386 | log_debug("Got DNS stub UDP query packet for id %u", DNS_PACKET_ID(p)); | |
387 | ||
388 | dns_stub_process_query(m, NULL, p); | |
389 | } else | |
390 | log_debug("Invalid DNS stub UDP packet, ignoring."); | |
391 | ||
392 | return 0; | |
393 | } | |
394 | ||
424e490b | 395 | static int manager_dns_stub_udp_fd(Manager *m) { |
b30bf55d LP |
396 | union sockaddr_union sa = { |
397 | .in.sin_family = AF_INET, | |
398 | .in.sin_port = htobe16(53), | |
399 | .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), | |
400 | }; | |
424e490b | 401 | _cleanup_close_ int fd = -1; |
b30bf55d LP |
402 | int r; |
403 | ||
404 | if (m->dns_stub_udp_fd >= 0) | |
405 | return m->dns_stub_udp_fd; | |
406 | ||
424e490b ZJS |
407 | fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
408 | if (fd < 0) | |
b30bf55d LP |
409 | return -errno; |
410 | ||
2ff48e98 LP |
411 | r = setsockopt_int(fd, SOL_SOCKET, SO_REUSEADDR, true); |
412 | if (r < 0) | |
413 | return r; | |
b30bf55d | 414 | |
2ff48e98 LP |
415 | r = setsockopt_int(fd, IPPROTO_IP, IP_PKTINFO, true); |
416 | if (r < 0) | |
417 | return r; | |
b30bf55d | 418 | |
2ff48e98 LP |
419 | r = setsockopt_int(fd, IPPROTO_IP, IP_RECVTTL, true); |
420 | if (r < 0) | |
421 | return r; | |
b30bf55d LP |
422 | |
423 | /* Make sure no traffic from outside the local host can leak to onto this socket */ | |
424e490b ZJS |
424 | if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3) < 0) |
425 | return -errno; | |
b30bf55d | 426 | |
424e490b ZJS |
427 | if (bind(fd, &sa.sa, sizeof(sa.in)) < 0) |
428 | return -errno; | |
b30bf55d | 429 | |
424e490b | 430 | r = sd_event_add_io(m->event, &m->dns_stub_udp_event_source, fd, EPOLLIN, on_dns_stub_packet, m); |
b30bf55d | 431 | if (r < 0) |
424e490b | 432 | return r; |
b30bf55d LP |
433 | |
434 | (void) sd_event_source_set_description(m->dns_stub_udp_event_source, "dns-stub-udp"); | |
435 | ||
c10d6bdb | 436 | return m->dns_stub_udp_fd = TAKE_FD(fd); |
b30bf55d LP |
437 | } |
438 | ||
439 | static int on_dns_stub_stream_packet(DnsStream *s) { | |
aa337a5e LP |
440 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
441 | ||
b30bf55d | 442 | assert(s); |
b30bf55d | 443 | |
aa337a5e LP |
444 | p = dns_stream_take_read_packet(s); |
445 | assert(p); | |
446 | ||
447 | if (dns_packet_validate_query(p) > 0) { | |
448 | log_debug("Got DNS stub TCP query packet for id %u", DNS_PACKET_ID(p)); | |
b30bf55d | 449 | |
aa337a5e | 450 | dns_stub_process_query(s->manager, s, p); |
b30bf55d LP |
451 | } else |
452 | log_debug("Invalid DNS stub TCP packet, ignoring."); | |
453 | ||
454 | /* Drop the reference to the stream. Either a query was created and added its own reference to the stream now, | |
455 | * or that didn't happen in which case we want to free the stream */ | |
456 | dns_stream_unref(s); | |
457 | ||
458 | return 0; | |
459 | } | |
460 | ||
461 | static int on_dns_stub_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
462 | DnsStream *stream; | |
463 | Manager *m = userdata; | |
464 | int cfd, r; | |
465 | ||
466 | cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); | |
467 | if (cfd < 0) { | |
3742095b | 468 | if (IN_SET(errno, EAGAIN, EINTR)) |
b30bf55d LP |
469 | return 0; |
470 | ||
471 | return -errno; | |
472 | } | |
473 | ||
91ccab1e | 474 | r = dns_stream_new(m, &stream, DNS_PROTOCOL_DNS, cfd, NULL); |
b30bf55d LP |
475 | if (r < 0) { |
476 | safe_close(cfd); | |
477 | return r; | |
478 | } | |
479 | ||
480 | stream->on_packet = on_dns_stub_stream_packet; | |
481 | ||
482 | /* We let the reference to the stream dangling here, it will either be dropped by the default "complete" action | |
483 | * of the stream, or by our packet callback, or when the manager is shut down. */ | |
484 | ||
485 | return 0; | |
486 | } | |
487 | ||
424e490b | 488 | static int manager_dns_stub_tcp_fd(Manager *m) { |
b30bf55d LP |
489 | union sockaddr_union sa = { |
490 | .in.sin_family = AF_INET, | |
491 | .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), | |
492 | .in.sin_port = htobe16(53), | |
493 | }; | |
424e490b | 494 | _cleanup_close_ int fd = -1; |
b30bf55d LP |
495 | int r; |
496 | ||
497 | if (m->dns_stub_tcp_fd >= 0) | |
498 | return m->dns_stub_tcp_fd; | |
499 | ||
424e490b ZJS |
500 | fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
501 | if (fd < 0) | |
b30bf55d LP |
502 | return -errno; |
503 | ||
2ff48e98 LP |
504 | r = setsockopt_int(fd, IPPROTO_IP, IP_TTL, true); |
505 | if (r < 0) | |
506 | return r; | |
b30bf55d | 507 | |
2ff48e98 LP |
508 | r = setsockopt_int(fd, SOL_SOCKET, SO_REUSEADDR, true); |
509 | if (r < 0) | |
510 | return r; | |
b30bf55d | 511 | |
2ff48e98 LP |
512 | r = setsockopt_int(fd, IPPROTO_IP, IP_PKTINFO, true); |
513 | if (r < 0) | |
514 | return r; | |
b30bf55d | 515 | |
2ff48e98 LP |
516 | r = setsockopt_int(fd, IPPROTO_IP, IP_RECVTTL, true); |
517 | if (r < 0) | |
518 | return r; | |
b30bf55d LP |
519 | |
520 | /* Make sure no traffic from outside the local host can leak to onto this socket */ | |
424e490b ZJS |
521 | if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, "lo", 3) < 0) |
522 | return -errno; | |
b30bf55d | 523 | |
424e490b ZJS |
524 | if (bind(fd, &sa.sa, sizeof(sa.in)) < 0) |
525 | return -errno; | |
b30bf55d | 526 | |
424e490b ZJS |
527 | if (listen(fd, SOMAXCONN) < 0) |
528 | return -errno; | |
b30bf55d | 529 | |
424e490b | 530 | r = sd_event_add_io(m->event, &m->dns_stub_tcp_event_source, fd, EPOLLIN, on_dns_stub_stream, m); |
b30bf55d | 531 | if (r < 0) |
424e490b | 532 | return r; |
b30bf55d LP |
533 | |
534 | (void) sd_event_source_set_description(m->dns_stub_tcp_event_source, "dns-stub-tcp"); | |
535 | ||
c10d6bdb | 536 | return m->dns_stub_tcp_fd = TAKE_FD(fd); |
b30bf55d LP |
537 | } |
538 | ||
539 | int manager_dns_stub_start(Manager *m) { | |
424e490b | 540 | const char *t = "UDP"; |
01b0669e | 541 | int r = 0; |
b30bf55d LP |
542 | |
543 | assert(m); | |
544 | ||
d5da7707 ZJS |
545 | if (m->dns_stub_listener_mode == DNS_STUB_LISTENER_NO) |
546 | log_debug("Not creating stub listener."); | |
547 | else | |
548 | log_debug("Creating stub listener using %s.", | |
549 | m->dns_stub_listener_mode == DNS_STUB_LISTENER_UDP ? "UDP" : | |
550 | m->dns_stub_listener_mode == DNS_STUB_LISTENER_TCP ? "TCP" : | |
551 | "UDP/TCP"); | |
552 | ||
424e490b | 553 | if (IN_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_YES, DNS_STUB_LISTENER_UDP)) |
1ae43295 | 554 | r = manager_dns_stub_udp_fd(m); |
b30bf55d | 555 | |
424e490b ZJS |
556 | if (r >= 0 && |
557 | IN_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_YES, DNS_STUB_LISTENER_TCP)) { | |
558 | t = "TCP"; | |
1ae43295 | 559 | r = manager_dns_stub_tcp_fd(m); |
1ae43295 | 560 | } |
b30bf55d | 561 | |
0f4db364 ZJS |
562 | if (IN_SET(r, -EADDRINUSE, -EPERM)) { |
563 | if (r == -EADDRINUSE) | |
564 | log_warning_errno(r, | |
565 | "Another process is already listening on %s socket 127.0.0.53:53.\n" | |
566 | "Turning off local DNS stub support.", t); | |
567 | else | |
568 | log_warning_errno(r, | |
569 | "Failed to listen on %s socket 127.0.0.53:53: %m.\n" | |
570 | "Turning off local DNS stub support.", t); | |
424e490b ZJS |
571 | manager_dns_stub_stop(m); |
572 | } else if (r < 0) | |
573 | return log_error_errno(r, "Failed to listen on %s socket 127.0.0.53:53: %m", t); | |
b30bf55d LP |
574 | |
575 | return 0; | |
576 | } | |
577 | ||
578 | void manager_dns_stub_stop(Manager *m) { | |
579 | assert(m); | |
580 | ||
581 | m->dns_stub_udp_event_source = sd_event_source_unref(m->dns_stub_udp_event_source); | |
582 | m->dns_stub_tcp_event_source = sd_event_source_unref(m->dns_stub_tcp_event_source); | |
583 | ||
584 | m->dns_stub_udp_fd = safe_close(m->dns_stub_udp_fd); | |
585 | m->dns_stub_tcp_fd = safe_close(m->dns_stub_tcp_fd); | |
586 | } |