]>
Commit | Line | Data |
---|---|---|
db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
b30bf55d | 2 | |
ca8b62b5 YW |
3 | #include <net/if_arp.h> |
4 | ||
4ff9bc2e | 5 | #include "errno-util.h" |
b30bf55d | 6 | #include "fd-util.h" |
ef118d00 | 7 | #include "missing_network.h" |
af8b1384 | 8 | #include "missing_socket.h" |
b30bf55d | 9 | #include "resolved-dns-stub.h" |
1f05101f | 10 | #include "socket-netlink.h" |
b30bf55d | 11 | #include "socket-util.h" |
ae8f0ec3 | 12 | #include "string-table.h" |
b30bf55d LP |
13 | |
14 | /* The MTU of the loopback device is 64K on Linux, advertise that as maximum datagram size, but subtract the Ethernet, | |
15 | * IP and UDP header sizes */ | |
16 | #define ADVERTISE_DATAGRAM_SIZE_MAX (65536U-14U-20U-8U) | |
17 | ||
b370adb5 LP |
18 | /* On the extra stubs, use a more conservative choice */ |
19 | #define ADVERTISE_EXTRA_DATAGRAM_SIZE_MAX DNS_PACKET_UNICAST_SIZE_LARGE_MAX | |
20 | ||
b5febb3f | 21 | static int manager_dns_stub_fd_extra(Manager *m, DnsStubListenerExtra *l, int type); |
0354029b | 22 | |
ae8f0ec3 LP |
23 | static void dns_stub_listener_extra_hash_func(const DnsStubListenerExtra *a, struct siphash *state) { |
24 | assert(a); | |
25 | ||
26 | siphash24_compress(&a->mode, sizeof(a->mode), state); | |
27 | siphash24_compress(&a->family, sizeof(a->family), state); | |
28 | siphash24_compress(&a->address, FAMILY_ADDRESS_SIZE(a->family), state); | |
29 | siphash24_compress(&a->port, sizeof(a->port), state); | |
30 | } | |
31 | ||
32 | static int dns_stub_listener_extra_compare_func(const DnsStubListenerExtra *a, const DnsStubListenerExtra *b) { | |
33 | int r; | |
34 | ||
35 | assert(a); | |
36 | assert(b); | |
37 | ||
38 | r = CMP(a->mode, b->mode); | |
39 | if (r != 0) | |
40 | return r; | |
41 | ||
42 | r = CMP(a->family, b->family); | |
43 | if (r != 0) | |
44 | return r; | |
45 | ||
46 | r = memcmp(&a->address, &b->address, FAMILY_ADDRESS_SIZE(a->family)); | |
47 | if (r != 0) | |
48 | return r; | |
49 | ||
50 | return CMP(a->port, b->port); | |
51 | } | |
52 | ||
53 | DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR( | |
54 | dns_stub_listener_extra_hash_ops, | |
55 | DnsStubListenerExtra, | |
56 | dns_stub_listener_extra_hash_func, | |
57 | dns_stub_listener_extra_compare_func, | |
58 | dns_stub_listener_extra_free); | |
59 | ||
0354029b LP |
60 | int dns_stub_listener_extra_new( |
61 | Manager *m, | |
62 | DnsStubListenerExtra **ret) { | |
ae8f0ec3 | 63 | |
36aaabc3 | 64 | DnsStubListenerExtra *l; |
1f05101f | 65 | |
0354029b | 66 | l = new(DnsStubListenerExtra, 1); |
1f05101f SS |
67 | if (!l) |
68 | return -ENOMEM; | |
69 | ||
0354029b LP |
70 | *l = (DnsStubListenerExtra) { |
71 | .manager = m, | |
72 | }; | |
1f05101f | 73 | |
0354029b | 74 | *ret = TAKE_PTR(l); |
1f05101f SS |
75 | return 0; |
76 | } | |
77 | ||
36aaabc3 | 78 | DnsStubListenerExtra *dns_stub_listener_extra_free(DnsStubListenerExtra *p) { |
bf22f231 YW |
79 | if (!p) |
80 | return NULL; | |
81 | ||
82 | p->udp_event_source = sd_event_source_unref(p->udp_event_source); | |
83 | p->tcp_event_source = sd_event_source_unref(p->tcp_event_source); | |
bf22f231 | 84 | |
bde69bbd LP |
85 | hashmap_free(p->queries_by_packet); |
86 | ||
bf22f231 YW |
87 | return mfree(p); |
88 | } | |
89 | ||
49ef064c LP |
90 | uint16_t dns_stub_listener_extra_port(DnsStubListenerExtra *p) { |
91 | assert(p); | |
92 | ||
93 | if (p->port > 0) | |
94 | return p->port; | |
95 | ||
96 | return 53; | |
97 | } | |
98 | ||
bde69bbd LP |
99 | static void stub_packet_hash_func(const DnsPacket *p, struct siphash *state) { |
100 | assert(p); | |
101 | ||
102 | siphash24_compress(&p->protocol, sizeof(p->protocol), state); | |
103 | siphash24_compress(&p->family, sizeof(p->family), state); | |
104 | siphash24_compress(&p->sender, sizeof(p->sender), state); | |
105 | siphash24_compress(&p->ipproto, sizeof(p->ipproto), state); | |
106 | siphash24_compress(&p->sender_port, sizeof(p->sender_port), state); | |
107 | siphash24_compress(DNS_PACKET_HEADER(p), sizeof(DnsPacketHeader), state); | |
108 | ||
109 | /* We don't bother hashing the full packet here, just the header */ | |
110 | } | |
111 | ||
112 | static int stub_packet_compare_func(const DnsPacket *x, const DnsPacket *y) { | |
113 | int r; | |
114 | ||
115 | r = CMP(x->protocol, y->protocol); | |
116 | if (r != 0) | |
117 | return r; | |
118 | ||
119 | r = CMP(x->family, y->family); | |
120 | if (r != 0) | |
121 | return r; | |
122 | ||
123 | r = memcmp(&x->sender, &y->sender, sizeof(x->sender)); | |
124 | if (r != 0) | |
125 | return r; | |
126 | ||
127 | r = CMP(x->ipproto, y->ipproto); | |
128 | if (r != 0) | |
129 | return r; | |
130 | ||
131 | r = CMP(x->sender_port, y->sender_port); | |
132 | if (r != 0) | |
133 | return r; | |
134 | ||
135 | return memcmp(DNS_PACKET_HEADER(x), DNS_PACKET_HEADER(y), sizeof(DnsPacketHeader)); | |
136 | } | |
137 | ||
138 | DEFINE_HASH_OPS(stub_packet_hash_ops, DnsPacket, stub_packet_hash_func, stub_packet_compare_func); | |
139 | ||
775ae354 LP |
140 | static int dns_stub_collect_answer_by_question( |
141 | DnsAnswer **reply, | |
51027656 | 142 | DnsAnswer *answer, |
775ae354 LP |
143 | DnsQuestion *question, |
144 | bool with_rrsig) { /* Add RRSIG RR matching each RR */ | |
b30bf55d | 145 | |
775ae354 | 146 | DnsAnswerItem *item; |
b30bf55d LP |
147 | int r; |
148 | ||
775ae354 | 149 | assert(reply); |
e8d23f92 | 150 | |
775ae354 | 151 | /* Copies all RRs from 'answer' into 'reply', if they match 'question'. */ |
b30bf55d | 152 | |
775ae354 LP |
153 | DNS_ANSWER_FOREACH_ITEM(item, answer) { |
154 | ||
155 | if (question) { | |
156 | bool match = false; | |
b30bf55d | 157 | |
775ae354 LP |
158 | r = dns_question_matches_rr(question, item->rr, NULL); |
159 | if (r < 0) | |
160 | return r; | |
161 | else if (r > 0) | |
162 | match = true; | |
163 | else { | |
164 | r = dns_question_matches_cname_or_dname(question, item->rr, NULL); | |
165 | if (r < 0) | |
166 | return r; | |
167 | if (r > 0) | |
168 | match = true; | |
169 | } | |
170 | ||
171 | if (!match) | |
172 | continue; | |
173 | } | |
174 | ||
175 | r = dns_answer_add_extend(reply, item->rr, item->ifindex, item->flags, item->rrsig); | |
e8d23f92 LP |
176 | if (r < 0) |
177 | return r; | |
b30bf55d | 178 | |
775ae354 LP |
179 | if (with_rrsig && item->rrsig) { |
180 | r = dns_answer_add_extend(reply, item->rrsig, item->ifindex, item->flags, NULL); | |
181 | if (r < 0) | |
182 | return r; | |
183 | } | |
e8d23f92 | 184 | } |
b30bf55d | 185 | |
775ae354 LP |
186 | return 0; |
187 | } | |
e8d23f92 | 188 | |
775ae354 LP |
189 | static int dns_stub_collect_answer_by_section( |
190 | DnsAnswer **reply, | |
191 | DnsAnswer *answer, | |
192 | DnsAnswerFlags section, | |
193 | DnsAnswer *exclude1, | |
194 | DnsAnswer *exclude2, | |
195 | bool with_dnssec) { /* Include DNSSEC RRs. RRSIG, NSEC, … */ | |
b30bf55d | 196 | |
775ae354 LP |
197 | DnsAnswerItem *item; |
198 | unsigned c = 0; | |
199 | int r; | |
b30bf55d | 200 | |
775ae354 LP |
201 | assert(reply); |
202 | ||
203 | /* Copies all RRs from 'answer' into 'reply', if they originate from the specified section. Also, | |
204 | * avoid any RRs listed in 'exclude'. */ | |
205 | ||
206 | DNS_ANSWER_FOREACH_ITEM(item, answer) { | |
207 | ||
208 | if (dns_answer_contains(exclude1, item->rr) || | |
209 | dns_answer_contains(exclude2, item->rr)) | |
210 | continue; | |
211 | ||
212 | if (!with_dnssec && | |
213 | dns_type_is_dnssec(item->rr->key->type)) | |
214 | continue; | |
215 | ||
216 | if (((item->flags ^ section) & (DNS_ANSWER_SECTION_ANSWER|DNS_ANSWER_SECTION_AUTHORITY|DNS_ANSWER_SECTION_ADDITIONAL)) != 0) | |
217 | continue; | |
218 | ||
219 | r = dns_answer_add_extend(reply, item->rr, item->ifindex, item->flags, item->rrsig); | |
b30bf55d LP |
220 | if (r < 0) |
221 | return r; | |
222 | ||
223 | c++; | |
775ae354 LP |
224 | |
225 | if (with_dnssec && item->rrsig) { | |
226 | r = dns_answer_add_extend(reply, item->rrsig, item->ifindex, item->flags, NULL); | |
227 | if (r < 0) | |
228 | return r; | |
229 | ||
230 | c++; | |
231 | } | |
b30bf55d | 232 | } |
e8d23f92 | 233 | |
775ae354 LP |
234 | return (int) c; |
235 | } | |
236 | ||
237 | static int dns_stub_assign_sections( | |
238 | DnsQuery *q, | |
239 | DnsQuestion *question, | |
240 | bool edns0_do) { | |
241 | ||
242 | int r; | |
243 | ||
244 | assert(q); | |
245 | assert(question); | |
246 | ||
247 | /* Let's assign the 'answer' and 'answer_auxiliary' RRs we collected to their respective sections in | |
248 | * the reply datagram. We try to reproduce a section assignment similar to what the upstream DNS | |
249 | * server responded to us. We use the DNS_ANSWER_SECTION_xyz flags to match things up, which is where | |
250 | * the original upstream's packet section assignment is stored in the DnsAnswer object. Not all RRs | |
251 | * in the 'answer' and 'answer_auxiliary' objects come with section information though (for example, | |
252 | * because they were synthesized locally, and not from a DNS packet). To deal with that we extend the | |
253 | * assignment logic a bit: anything from the 'answer' object that directly matches the original | |
254 | * question is always put in the ANSWER section, regardless if it carries section info, or what that | |
255 | * section info says. Then, anything from the 'answer' and 'answer_auxiliary' objects that is from | |
256 | * the ANSWER or AUTHORITY sections, and wasn't already added to the ANSWER section is placed in the | |
257 | * AUTHORITY section. Everything else from either object is added to the ADDITIONAL section. */ | |
258 | ||
259 | /* Include all RRs that directly answer the question in the answer section */ | |
260 | r = dns_stub_collect_answer_by_question( | |
261 | &q->reply_answer, | |
262 | q->answer, | |
263 | question, | |
264 | edns0_do); | |
265 | if (r < 0) | |
266 | return r; | |
267 | ||
268 | /* Include all RRs that originate from the answer or authority sections, and aren't listed in the | |
269 | * answer section, in the authority section */ | |
270 | r = dns_stub_collect_answer_by_section( | |
271 | &q->reply_authoritative, | |
272 | q->answer, | |
273 | DNS_ANSWER_SECTION_ANSWER, | |
274 | q->reply_answer, NULL, | |
275 | edns0_do); | |
276 | if (r < 0) | |
277 | return r; | |
278 | ||
279 | /* Include all RRs that originate from the answer or authority sections, and aren't listed in the | |
280 | * answer section, in the authority section */ | |
281 | r = dns_stub_collect_answer_by_section( | |
282 | &q->reply_authoritative, | |
283 | q->answer, | |
284 | DNS_ANSWER_SECTION_AUTHORITY, | |
285 | q->reply_answer, NULL, | |
286 | edns0_do); | |
287 | if (r < 0) | |
288 | return r; | |
289 | ||
290 | /* Include all RRs that originate from the additional sections in the additional section (except if | |
291 | * already listed in the other two sections). Also add all RRs with no section marking. */ | |
292 | r = dns_stub_collect_answer_by_section( | |
293 | &q->reply_additional, | |
294 | q->answer, | |
295 | DNS_ANSWER_SECTION_ADDITIONAL, | |
296 | q->reply_answer, q->reply_authoritative, | |
297 | edns0_do); | |
298 | if (r < 0) | |
299 | return r; | |
300 | r = dns_stub_collect_answer_by_section( | |
301 | &q->reply_additional, | |
302 | q->answer, | |
303 | 0, | |
304 | q->reply_answer, q->reply_authoritative, | |
305 | edns0_do); | |
306 | if (r < 0) | |
307 | return r; | |
308 | ||
309 | return 0; | |
310 | } | |
311 | ||
312 | static int dns_stub_make_reply_packet( | |
313 | DnsPacket **ret, | |
314 | size_t max_size, | |
315 | DnsQuestion *q, | |
316 | bool *ret_truncated) { | |
317 | ||
318 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
319 | bool tc = false; | |
320 | int r; | |
321 | ||
322 | assert(ret); | |
323 | ||
324 | r = dns_packet_new(&p, DNS_PROTOCOL_DNS, 0, max_size); | |
325 | if (r < 0) | |
326 | return r; | |
327 | ||
328 | r = dns_packet_append_question(p, q); | |
329 | if (r == -EMSGSIZE) | |
330 | tc = true; | |
331 | else if (r < 0) | |
332 | return r; | |
333 | ||
51027656 | 334 | if (ret_truncated) |
775ae354 LP |
335 | *ret_truncated = tc; |
336 | else if (tc) | |
51027656 LP |
337 | return -EMSGSIZE; |
338 | ||
775ae354 | 339 | DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q)); |
e8d23f92 | 340 | |
775ae354 LP |
341 | *ret = TAKE_PTR(p); |
342 | return 0; | |
343 | } | |
344 | ||
345 | static int dns_stub_add_reply_packet_body( | |
346 | DnsPacket *p, | |
347 | DnsAnswer *answer, | |
348 | DnsAnswer *authoritative, | |
349 | DnsAnswer *additional, | |
350 | bool edns0_do, /* Client expects DNSSEC RRs? */ | |
351 | bool *truncated) { | |
352 | ||
353 | unsigned n_answer = 0, n_authoritative = 0, n_additional = 0; | |
354 | bool tc = false; | |
355 | int r; | |
356 | ||
357 | assert(p); | |
358 | ||
359 | /* Add the three sections to the packet. If the answer section doesn't fit we'll signal that as | |
360 | * truncation. If the authoritative section doesn't fit and we are in DNSSEC mode, also signal | |
361 | * truncation. In all other cases where things don't fit don't signal truncation, as for those cases | |
362 | * the dropped RRs should not be essential. */ | |
363 | ||
364 | r = dns_packet_append_answer(p, answer, &n_answer); | |
365 | if (r == -EMSGSIZE) | |
366 | tc = true; | |
367 | else if (r < 0) | |
368 | return r; | |
369 | else { | |
370 | r = dns_packet_append_answer(p, authoritative, &n_authoritative); | |
371 | if (r == -EMSGSIZE) { | |
372 | if (edns0_do) | |
373 | tc = true; | |
374 | } else if (r < 0) | |
375 | return r; | |
376 | else { | |
377 | r = dns_packet_append_answer(p, additional, &n_additional); | |
378 | if (r < 0 && r != -EMSGSIZE) | |
379 | return r; | |
380 | } | |
381 | } | |
382 | ||
383 | if (tc) { | |
384 | if (!truncated) | |
385 | return -EMSGSIZE; | |
386 | ||
387 | *truncated = true; | |
388 | } | |
389 | ||
390 | DNS_PACKET_HEADER(p)->ancount = htobe16(n_answer); | |
391 | DNS_PACKET_HEADER(p)->nscount = htobe16(n_authoritative); | |
392 | DNS_PACKET_HEADER(p)->arcount = htobe16(n_additional); | |
e8d23f92 LP |
393 | return 0; |
394 | } | |
395 | ||
396 | static int dns_stub_finish_reply_packet( | |
397 | DnsPacket *p, | |
398 | uint16_t id, | |
399 | int rcode, | |
51027656 | 400 | bool tc, /* set the Truncated bit? */ |
e8d23f92 LP |
401 | bool add_opt, /* add an OPT RR to this packet? */ |
402 | bool edns0_do, /* set the EDNS0 DNSSEC OK bit? */ | |
b370adb5 | 403 | bool ad, /* set the DNSSEC authenticated data bit? */ |
775ae354 | 404 | bool cd, /* set the DNSSEC checking disabled bit? */ |
b370adb5 | 405 | uint16_t max_udp_size) { /* The maximum UDP datagram size to advertise to clients */ |
e8d23f92 LP |
406 | |
407 | int r; | |
408 | ||
409 | assert(p); | |
410 | ||
ff4caaae | 411 | if (add_opt) { |
b370adb5 | 412 | r = dns_packet_append_opt(p, max_udp_size, edns0_do, /* include_rfc6975 = */ false, rcode, NULL); |
ff4caaae LP |
413 | if (r == -EMSGSIZE) /* Hit the size limit? then indicate truncation */ |
414 | tc = true; | |
415 | else if (r < 0) | |
416 | return r; | |
ff4caaae | 417 | } else { |
941dd294 LP |
418 | /* If the client can't to EDNS0, don't do DO either */ |
419 | edns0_do = false; | |
420 | ||
775ae354 | 421 | /* If we don't do EDNS, clamp the rcode to 4 bit */ |
941dd294 LP |
422 | if (rcode > 0xF) |
423 | rcode = DNS_RCODE_SERVFAIL; | |
424 | } | |
425 | ||
8c9c68b5 LP |
426 | /* Don't set the CD bit unless DO is on, too */ |
427 | if (!edns0_do) | |
775ae354 LP |
428 | cd = false; |
429 | ||
8c9c68b5 LP |
430 | /* Note that we allow the AD bit to be set even if client didn't signal DO, as per RFC 6840, section |
431 | * 5.7 */ | |
e8d23f92 LP |
432 | |
433 | DNS_PACKET_HEADER(p)->id = id; | |
434 | ||
435 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( | |
51027656 LP |
436 | 1 /* qr */, |
437 | 0 /* opcode */, | |
438 | 0 /* aa */, | |
439 | tc /* tc */, | |
440 | 1 /* rd */, | |
441 | 1 /* ra */, | |
e8d23f92 | 442 | ad /* ad */, |
775ae354 | 443 | cd /* cd */, |
e8d23f92 | 444 | rcode)); |
b30bf55d | 445 | |
b30bf55d LP |
446 | return 0; |
447 | } | |
448 | ||
0354029b LP |
449 | static int dns_stub_send( |
450 | Manager *m, | |
451 | DnsStubListenerExtra *l, | |
452 | DnsStream *s, | |
453 | DnsPacket *p, | |
454 | DnsPacket *reply) { | |
455 | ||
b30bf55d LP |
456 | int r; |
457 | ||
458 | assert(m); | |
459 | assert(p); | |
460 | assert(reply); | |
461 | ||
462 | if (s) | |
463 | r = dns_stream_write_packet(s, reply); | |
0354029b | 464 | else |
b30bf55d LP |
465 | /* Note that it is essential here that we explicitly choose the source IP address for this packet. This |
466 | * is because otherwise the kernel will choose it automatically based on the routing table and will | |
467 | * thus pick 127.0.0.1 rather than 127.0.0.53. */ | |
0354029b | 468 | r = manager_send(m, |
b5febb3f | 469 | manager_dns_stub_fd_extra(m, l, SOCK_DGRAM), |
0354029b LP |
470 | l ? p->ifindex : LOOPBACK_IFINDEX, /* force loopback iface if this is the main listener stub */ |
471 | p->family, &p->sender, p->sender_port, &p->destination, | |
472 | reply); | |
b30bf55d LP |
473 | if (r < 0) |
474 | return log_debug_errno(r, "Failed to send reply packet: %m"); | |
475 | ||
476 | return 0; | |
477 | } | |
478 | ||
775ae354 LP |
479 | static int dns_stub_send_reply( |
480 | DnsQuery *q, | |
481 | int rcode) { | |
482 | ||
483 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; | |
484 | bool truncated, edns0_do; | |
485 | int r; | |
486 | ||
487 | assert(q); | |
488 | ||
489 | /* Reply with DNSSEC DO set? Only if client supports it; and we did any DNSSEC verification | |
490 | * ourselves, or consider the data fully authenticated because we generated it locally, or | |
491 | * the client set cd */ | |
492 | edns0_do = | |
493 | DNS_PACKET_DO(q->request_packet) && | |
494 | (q->answer_dnssec_result >= 0 || /* we did proper DNSSEC validation … */ | |
495 | dns_query_fully_authenticated(q) || /* … or we considered it authentic otherwise … */ | |
496 | DNS_PACKET_CD(q->request_packet)); /* … or client set CD */ | |
497 | ||
498 | r = dns_stub_assign_sections( | |
499 | q, | |
500 | q->request_packet->question, | |
501 | edns0_do); | |
502 | if (r < 0) | |
503 | return log_debug_errno(r, "Failed to assign sections: %m"); | |
504 | ||
505 | r = dns_stub_make_reply_packet( | |
506 | &reply, | |
507 | DNS_PACKET_PAYLOAD_SIZE_MAX(q->request_packet), | |
508 | q->request_packet->question, | |
509 | &truncated); | |
510 | if (r < 0) | |
511 | return log_debug_errno(r, "Failed to build reply packet: %m"); | |
512 | ||
513 | r = dns_stub_add_reply_packet_body( | |
514 | reply, | |
515 | q->reply_answer, | |
516 | q->reply_authoritative, | |
517 | q->reply_additional, | |
518 | edns0_do, | |
519 | &truncated); | |
520 | if (r < 0) | |
521 | return log_debug_errno(r, "Failed to append reply packet body: %m"); | |
522 | ||
523 | r = dns_stub_finish_reply_packet( | |
524 | reply, | |
525 | DNS_PACKET_ID(q->request_packet), | |
526 | rcode, | |
527 | truncated, | |
528 | !!q->request_packet->opt, | |
529 | edns0_do, | |
8c9c68b5 | 530 | DNS_PACKET_AD(q->request_packet) && dns_query_fully_authenticated(q), |
775ae354 LP |
531 | DNS_PACKET_CD(q->request_packet), |
532 | q->stub_listener_extra ? ADVERTISE_EXTRA_DATAGRAM_SIZE_MAX : ADVERTISE_DATAGRAM_SIZE_MAX); | |
533 | if (r < 0) | |
534 | return log_debug_errno(r, "Failed to build failure packet: %m"); | |
535 | ||
536 | return dns_stub_send(q->manager, q->stub_listener_extra, q->request_stream, q->request_packet, reply); | |
537 | } | |
538 | ||
0354029b LP |
539 | static int dns_stub_send_failure( |
540 | Manager *m, | |
541 | DnsStubListenerExtra *l, | |
542 | DnsStream *s, | |
543 | DnsPacket *p, | |
544 | int rcode, | |
545 | bool authenticated) { | |
546 | ||
b30bf55d | 547 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; |
775ae354 | 548 | bool truncated; |
b30bf55d LP |
549 | int r; |
550 | ||
551 | assert(m); | |
552 | assert(p); | |
553 | ||
775ae354 LP |
554 | r = dns_stub_make_reply_packet( |
555 | &reply, | |
556 | DNS_PACKET_PAYLOAD_SIZE_MAX(p), | |
557 | p->question, | |
558 | &truncated); | |
e8d23f92 LP |
559 | if (r < 0) |
560 | return log_debug_errno(r, "Failed to make failure packet: %m"); | |
561 | ||
b370adb5 LP |
562 | r = dns_stub_finish_reply_packet( |
563 | reply, | |
564 | DNS_PACKET_ID(p), | |
565 | rcode, | |
775ae354 | 566 | truncated, |
b370adb5 LP |
567 | !!p->opt, |
568 | DNS_PACKET_DO(p), | |
8c9c68b5 | 569 | DNS_PACKET_AD(p) && authenticated, |
775ae354 | 570 | DNS_PACKET_CD(p), |
b370adb5 | 571 | l ? ADVERTISE_EXTRA_DATAGRAM_SIZE_MAX : ADVERTISE_DATAGRAM_SIZE_MAX); |
b30bf55d LP |
572 | if (r < 0) |
573 | return log_debug_errno(r, "Failed to build failure packet: %m"); | |
574 | ||
0354029b | 575 | return dns_stub_send(m, l, s, p, reply); |
b30bf55d LP |
576 | } |
577 | ||
775ae354 LP |
578 | static int dns_stub_patch_bypass_reply_packet( |
579 | DnsPacket **ret, /* Where to place the patched packet */ | |
580 | DnsPacket *original, /* The packet to patch */ | |
581 | DnsPacket *request) { /* The packet the patched packet shall look like a reply to */ | |
582 | _cleanup_(dns_packet_unrefp) DnsPacket *c = NULL; | |
583 | int r; | |
584 | ||
585 | assert(ret); | |
586 | assert(original); | |
587 | assert(request); | |
588 | ||
589 | r = dns_packet_dup(&c, original); | |
590 | if (r < 0) | |
591 | return r; | |
592 | ||
593 | /* Extract the packet, so that we know where the OPT field is */ | |
594 | r = dns_packet_extract(c); | |
595 | if (r < 0) | |
596 | return r; | |
597 | ||
598 | /* Copy over the original client request ID, so that we can make the upstream query look like our own reply. */ | |
599 | DNS_PACKET_HEADER(c)->id = DNS_PACKET_HEADER(request)->id; | |
600 | ||
601 | /* Patch in our own maximum datagram size, if EDNS0 was on */ | |
602 | r = dns_packet_patch_max_udp_size(c, ADVERTISE_DATAGRAM_SIZE_MAX); | |
603 | if (r < 0) | |
604 | return r; | |
605 | ||
606 | /* Lower all TTLs by the time passed since we received the datagram. */ | |
607 | if (timestamp_is_set(original->timestamp)) { | |
608 | r = dns_packet_patch_ttls(c, original->timestamp); | |
609 | if (r < 0) | |
610 | return r; | |
611 | } | |
612 | ||
613 | /* Our upstream connection might have supported larger DNS requests than our downstream one, hence | |
614 | * set the TC bit if our reply is larger than what the client supports, and truncate. */ | |
615 | if (c->size > DNS_PACKET_PAYLOAD_SIZE_MAX(request)) { | |
616 | log_debug("Artificially truncating stub response, as advertised size of client is smaller than upstream one."); | |
617 | dns_packet_truncate(c, DNS_PACKET_PAYLOAD_SIZE_MAX(request)); | |
618 | DNS_PACKET_HEADER(c)->flags = htobe16(be16toh(DNS_PACKET_HEADER(c)->flags) | DNS_PACKET_FLAG_TC); | |
619 | } | |
620 | ||
621 | *ret = TAKE_PTR(c); | |
622 | return 0; | |
623 | } | |
624 | ||
b30bf55d LP |
625 | static void dns_stub_query_complete(DnsQuery *q) { |
626 | int r; | |
627 | ||
628 | assert(q); | |
775ae354 | 629 | assert(q->request_packet); |
b30bf55d | 630 | |
775ae354 LP |
631 | if (q->question_bypass) { |
632 | /* This is a bypass reply. If so, let's propagate the upstream packet, if we have it and it | |
633 | * is regular DNS. (We can't do this if the upstream packet is LLMNR or mDNS, since the | |
634 | * packets are not 100% compatible.) */ | |
b30bf55d | 635 | |
775ae354 LP |
636 | if (q->answer_full_packet && |
637 | q->answer_full_packet->protocol == DNS_PROTOCOL_DNS) { | |
638 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; | |
e8d23f92 | 639 | |
775ae354 LP |
640 | r = dns_stub_patch_bypass_reply_packet(&reply, q->answer_full_packet, q->request_packet); |
641 | if (r < 0) | |
642 | log_debug_errno(r, "Failed to patch bypass reply packet: %m"); | |
643 | else | |
644 | (void) dns_stub_send(q->manager, q->stub_listener_extra, q->request_stream, q->request_packet, reply); | |
645 | ||
646 | dns_query_free(q); | |
647 | return; | |
e8d23f92 | 648 | } |
775ae354 | 649 | } |
b30bf55d | 650 | |
775ae354 LP |
651 | switch (q->state) { |
652 | ||
653 | case DNS_TRANSACTION_SUCCESS: | |
654 | /* Follow CNAMEs, and accumulate answers. Except if DNSSEC is requested, then let the client do that. */ | |
655 | if (!DNS_PACKET_DO(q->request_packet)) { | |
aa11cab9 | 656 | r = dns_query_process_cname(q); |
775ae354 LP |
657 | if (r == -ELOOP) { /* CNAME loop */ |
658 | (void) dns_stub_send_reply(q, DNS_RCODE_SERVFAIL); | |
aa11cab9 LP |
659 | break; |
660 | } | |
661 | if (r < 0) { | |
662 | log_debug_errno(r, "Failed to process CNAME: %m"); | |
663 | break; | |
664 | } | |
665 | if (r == DNS_QUERY_RESTARTED) | |
666 | return; | |
e8d23f92 | 667 | } |
e8d23f92 | 668 | |
775ae354 | 669 | (void) dns_stub_send_reply(q, q->answer_rcode); |
b30bf55d | 670 | break; |
b30bf55d LP |
671 | |
672 | case DNS_TRANSACTION_RCODE_FAILURE: | |
775ae354 | 673 | (void) dns_stub_send_reply(q, q->answer_rcode); |
b30bf55d LP |
674 | break; |
675 | ||
676 | case DNS_TRANSACTION_NOT_FOUND: | |
775ae354 | 677 | (void) dns_stub_send_reply(q, DNS_RCODE_NXDOMAIN); |
b30bf55d LP |
678 | break; |
679 | ||
680 | case DNS_TRANSACTION_TIMEOUT: | |
681 | case DNS_TRANSACTION_ATTEMPTS_MAX_REACHED: | |
682 | /* Propagate a timeout as a no packet, i.e. that the client also gets a timeout */ | |
683 | break; | |
684 | ||
685 | case DNS_TRANSACTION_NO_SERVERS: | |
686 | case DNS_TRANSACTION_INVALID_REPLY: | |
687 | case DNS_TRANSACTION_ERRNO: | |
688 | case DNS_TRANSACTION_ABORTED: | |
689 | case DNS_TRANSACTION_DNSSEC_FAILED: | |
690 | case DNS_TRANSACTION_NO_TRUST_ANCHOR: | |
691 | case DNS_TRANSACTION_RR_TYPE_UNSUPPORTED: | |
692 | case DNS_TRANSACTION_NETWORK_DOWN: | |
775ae354 | 693 | case DNS_TRANSACTION_NO_SOURCE: |
49ef064c | 694 | case DNS_TRANSACTION_STUB_LOOP: |
775ae354 | 695 | (void) dns_stub_send_reply(q, DNS_RCODE_SERVFAIL); |
b30bf55d LP |
696 | break; |
697 | ||
698 | case DNS_TRANSACTION_NULL: | |
699 | case DNS_TRANSACTION_PENDING: | |
700 | case DNS_TRANSACTION_VALIDATING: | |
701 | default: | |
702 | assert_not_reached("Impossible state"); | |
703 | } | |
704 | ||
b30bf55d LP |
705 | dns_query_free(q); |
706 | } | |
707 | ||
708 | static int dns_stub_stream_complete(DnsStream *s, int error) { | |
709 | assert(s); | |
710 | ||
b412af57 LP |
711 | log_debug_errno(error, "DNS TCP connection terminated, destroying queries: %m"); |
712 | ||
713 | for (;;) { | |
714 | DnsQuery *q; | |
715 | ||
716 | q = set_first(s->queries); | |
717 | if (!q) | |
718 | break; | |
b30bf55d | 719 | |
b412af57 LP |
720 | dns_query_free(q); |
721 | } | |
b30bf55d | 722 | |
b412af57 LP |
723 | /* This drops the implicit ref we keep around since it was allocated, as incoming stub connections |
724 | * should be kept as long as the client wants to. */ | |
725 | dns_stream_unref(s); | |
b30bf55d LP |
726 | return 0; |
727 | } | |
728 | ||
0354029b | 729 | static void dns_stub_process_query(Manager *m, DnsStubListenerExtra *l, DnsStream *s, DnsPacket *p) { |
ceb17827 | 730 | _cleanup_(dns_query_freep) DnsQuery *q = NULL; |
bde69bbd LP |
731 | Hashmap **queries_by_packet; |
732 | DnsQuery *existing; | |
b30bf55d LP |
733 | int r; |
734 | ||
735 | assert(m); | |
736 | assert(p); | |
737 | assert(p->protocol == DNS_PROTOCOL_DNS); | |
738 | ||
0354029b | 739 | if (!l && /* l == NULL if this is the main stub */ |
d1fb8cda YW |
740 | (in_addr_is_localhost(p->family, &p->sender) <= 0 || |
741 | in_addr_is_localhost(p->family, &p->destination) <= 0)) { | |
565147b7 | 742 | log_warning("Got packet on unexpected (i.e. non-localhost) IP range, ignoring."); |
ceb17827 | 743 | return; |
b30bf55d LP |
744 | } |
745 | ||
a9fd8837 LP |
746 | if (manager_packet_from_our_transaction(m, p)) { |
747 | log_debug("Got our own packet looped back, ignoring."); | |
748 | return; | |
749 | } | |
750 | ||
bde69bbd LP |
751 | queries_by_packet = l ? &l->queries_by_packet : &m->stub_queries_by_packet; |
752 | existing = hashmap_get(*queries_by_packet, p); | |
753 | if (existing && dns_packet_equal(existing->request_packet, p)) { | |
754 | log_debug("Got repeat packet from client, ignoring."); | |
755 | return; | |
756 | } | |
757 | ||
b30bf55d LP |
758 | r = dns_packet_extract(p); |
759 | if (r < 0) { | |
760 | log_debug_errno(r, "Failed to extract resources from incoming packet, ignoring packet: %m"); | |
0354029b | 761 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_FORMERR, false); |
ceb17827 | 762 | return; |
b30bf55d LP |
763 | } |
764 | ||
765 | if (!DNS_PACKET_VERSION_SUPPORTED(p)) { | |
766 | log_debug("Got EDNS OPT field with unsupported version number."); | |
0354029b | 767 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_BADVERS, false); |
ceb17827 | 768 | return; |
b30bf55d LP |
769 | } |
770 | ||
771 | if (dns_type_is_obsolete(p->question->keys[0]->type)) { | |
772 | log_debug("Got message with obsolete key type, refusing."); | |
30ee7071 | 773 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_REFUSED, false); |
ceb17827 | 774 | return; |
b30bf55d LP |
775 | } |
776 | ||
777 | if (dns_type_is_zone_transer(p->question->keys[0]->type)) { | |
778 | log_debug("Got request for zone transfer, refusing."); | |
30ee7071 | 779 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_REFUSED, false); |
ceb17827 | 780 | return; |
b30bf55d LP |
781 | } |
782 | ||
783 | if (!DNS_PACKET_RD(p)) { | |
784 | /* If the "rd" bit is off (i.e. recursion was not requested), then refuse operation */ | |
785 | log_debug("Got request with recursion disabled, refusing."); | |
0354029b | 786 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_REFUSED, false); |
ceb17827 | 787 | return; |
b30bf55d LP |
788 | } |
789 | ||
bde69bbd LP |
790 | r = hashmap_ensure_allocated(queries_by_packet, &stub_packet_hash_ops); |
791 | if (r < 0) { | |
792 | log_oom(); | |
793 | return; | |
794 | } | |
795 | ||
b30bf55d | 796 | if (DNS_PACKET_DO(p) && DNS_PACKET_CD(p)) { |
775ae354 LP |
797 | log_debug("Got request with DNSSEC checking disabled, enabling bypass logic."); |
798 | ||
799 | r = dns_query_new(m, &q, NULL, NULL, p, 0, | |
800 | SD_RESOLVED_PROTOCOLS_ALL| | |
801 | SD_RESOLVED_NO_CNAME| | |
802 | SD_RESOLVED_NO_SEARCH| | |
803 | SD_RESOLVED_NO_VALIDATE| | |
804 | SD_RESOLVED_REQUIRE_PRIMARY| | |
805 | SD_RESOLVED_CLAMP_TTL); | |
806 | } else | |
807 | r = dns_query_new(m, &q, p->question, p->question, NULL, 0, | |
808 | SD_RESOLVED_PROTOCOLS_ALL| | |
809 | SD_RESOLVED_NO_SEARCH| | |
810 | (DNS_PACKET_DO(p) ? SD_RESOLVED_NO_CNAME|SD_RESOLVED_REQUIRE_PRIMARY : 0)| | |
811 | SD_RESOLVED_CLAMP_TTL); | |
b30bf55d LP |
812 | if (r < 0) { |
813 | log_error_errno(r, "Failed to generate query object: %m"); | |
0354029b | 814 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_SERVFAIL, false); |
ceb17827 | 815 | return; |
b30bf55d LP |
816 | } |
817 | ||
775ae354 LP |
818 | q->request_packet = dns_packet_ref(p); |
819 | q->request_stream = dns_stream_ref(s); /* make sure the stream stays around until we can send a reply through it */ | |
0354029b | 820 | q->stub_listener_extra = l; |
b30bf55d LP |
821 | q->complete = dns_stub_query_complete; |
822 | ||
823 | if (s) { | |
b412af57 LP |
824 | /* Remember which queries belong to this stream, so that we can cancel them when the stream |
825 | * is disconnected early */ | |
826 | ||
ceb17827 | 827 | r = set_ensure_put(&s->queries, NULL, q); |
b412af57 LP |
828 | if (r < 0) { |
829 | log_oom(); | |
ceb17827 | 830 | return; |
b412af57 | 831 | } |
ceb17827 | 832 | assert(r > 0); |
b30bf55d LP |
833 | } |
834 | ||
bde69bbd LP |
835 | /* Add the query to the hash table we use to determine repeat packets now. We don't care about |
836 | * failures here, since in the worst case we'll not recognize duplicate incoming requests, which | |
837 | * isn't particularly bad. */ | |
838 | (void) hashmap_put(*queries_by_packet, q->request_packet, q); | |
839 | ||
b30bf55d LP |
840 | r = dns_query_go(q); |
841 | if (r < 0) { | |
842 | log_error_errno(r, "Failed to start query: %m"); | |
0354029b | 843 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_SERVFAIL, false); |
ceb17827 | 844 | return; |
b30bf55d LP |
845 | } |
846 | ||
52e63427 | 847 | log_debug("Processing query..."); |
ceb17827 | 848 | TAKE_PTR(q); |
b30bf55d LP |
849 | } |
850 | ||
0354029b | 851 | static int on_dns_stub_packet_internal(sd_event_source *s, int fd, uint32_t revents, Manager *m, DnsStubListenerExtra *l) { |
b30bf55d | 852 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
b30bf55d LP |
853 | int r; |
854 | ||
855 | r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p); | |
856 | if (r <= 0) | |
857 | return r; | |
858 | ||
859 | if (dns_packet_validate_query(p) > 0) { | |
860 | log_debug("Got DNS stub UDP query packet for id %u", DNS_PACKET_ID(p)); | |
861 | ||
0354029b | 862 | dns_stub_process_query(m, l, NULL, p); |
b30bf55d LP |
863 | } else |
864 | log_debug("Invalid DNS stub UDP packet, ignoring."); | |
865 | ||
866 | return 0; | |
867 | } | |
868 | ||
d1fb8cda | 869 | static int on_dns_stub_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
0354029b | 870 | return on_dns_stub_packet_internal(s, fd, revents, userdata, NULL); |
d1fb8cda YW |
871 | } |
872 | ||
873 | static int on_dns_stub_packet_extra(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
0354029b LP |
874 | DnsStubListenerExtra *l = userdata; |
875 | ||
876 | assert(l); | |
877 | ||
878 | return on_dns_stub_packet_internal(s, fd, revents, l->manager, l); | |
d1fb8cda YW |
879 | } |
880 | ||
e4bed40f ZJS |
881 | static int on_dns_stub_stream_packet(DnsStream *s) { |
882 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
883 | ||
884 | assert(s); | |
885 | ||
886 | p = dns_stream_take_read_packet(s); | |
887 | assert(p); | |
888 | ||
889 | if (dns_packet_validate_query(p) > 0) { | |
890 | log_debug("Got DNS stub TCP query packet for id %u", DNS_PACKET_ID(p)); | |
891 | ||
892 | dns_stub_process_query(s->manager, s->stub_listener_extra, s, p); | |
893 | } else | |
894 | log_debug("Invalid DNS stub TCP packet, ignoring."); | |
895 | ||
896 | return 0; | |
897 | } | |
898 | ||
899 | static int on_dns_stub_stream_internal(sd_event_source *s, int fd, uint32_t revents, Manager *m, DnsStubListenerExtra *l) { | |
900 | DnsStream *stream; | |
901 | int cfd, r; | |
902 | ||
903 | cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); | |
904 | if (cfd < 0) { | |
905 | if (ERRNO_IS_ACCEPT_AGAIN(errno)) | |
906 | return 0; | |
907 | ||
908 | return -errno; | |
909 | } | |
910 | ||
911 | r = dns_stream_new(m, &stream, DNS_STREAM_STUB, DNS_PROTOCOL_DNS, cfd, NULL); | |
912 | if (r < 0) { | |
913 | safe_close(cfd); | |
914 | return r; | |
915 | } | |
916 | ||
917 | stream->stub_listener_extra = l; | |
918 | stream->on_packet = on_dns_stub_stream_packet; | |
919 | stream->complete = dns_stub_stream_complete; | |
920 | ||
921 | /* We let the reference to the stream dangle here, it will be dropped later by the complete callback. */ | |
922 | ||
923 | return 0; | |
924 | } | |
925 | ||
926 | static int on_dns_stub_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
927 | return on_dns_stub_stream_internal(s, fd, revents, userdata, NULL); | |
928 | } | |
929 | ||
930 | static int on_dns_stub_stream_extra(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
931 | DnsStubListenerExtra *l = userdata; | |
932 | ||
933 | assert(l); | |
934 | return on_dns_stub_stream_internal(s, fd, revents, l->manager, l); | |
935 | } | |
936 | ||
af8b1384 | 937 | static int set_dns_stub_common_socket_options(int fd, int family) { |
1f05101f SS |
938 | int r; |
939 | ||
940 | assert(fd >= 0); | |
af8b1384 | 941 | assert(IN_SET(family, AF_INET, AF_INET6)); |
1f05101f SS |
942 | |
943 | r = setsockopt_int(fd, SOL_SOCKET, SO_REUSEADDR, true); | |
944 | if (r < 0) | |
945 | return r; | |
946 | ||
5d0fe423 LP |
947 | r = socket_set_recvpktinfo(fd, family, true); |
948 | if (r < 0) | |
949 | return r; | |
af8b1384 | 950 | |
5d0fe423 LP |
951 | r = socket_set_recvttl(fd, family, true); |
952 | if (r < 0) | |
953 | return r; | |
af8b1384 YW |
954 | |
955 | return 0; | |
1f05101f SS |
956 | } |
957 | ||
d491917c | 958 | static int manager_dns_stub_fd(Manager *m, int type) { |
b30bf55d LP |
959 | union sockaddr_union sa = { |
960 | .in.sin_family = AF_INET, | |
b30bf55d | 961 | .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), |
d491917c | 962 | .in.sin_port = htobe16(53), |
b30bf55d | 963 | }; |
424e490b | 964 | _cleanup_close_ int fd = -1; |
b30bf55d LP |
965 | int r; |
966 | ||
d491917c ZJS |
967 | assert(IN_SET(type, SOCK_DGRAM, SOCK_STREAM)); |
968 | ||
969 | sd_event_source **event_source = type == SOCK_DGRAM ? &m->dns_stub_udp_event_source : &m->dns_stub_tcp_event_source; | |
970 | if (*event_source) | |
971 | return sd_event_source_get_io_fd(*event_source); | |
b30bf55d | 972 | |
d491917c | 973 | fd = socket(AF_INET, type | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); |
424e490b | 974 | if (fd < 0) |
b30bf55d LP |
975 | return -errno; |
976 | ||
af8b1384 | 977 | r = set_dns_stub_common_socket_options(fd, AF_INET); |
2ff48e98 LP |
978 | if (r < 0) |
979 | return r; | |
b30bf55d LP |
980 | |
981 | /* Make sure no traffic from outside the local host can leak to onto this socket */ | |
953a02d1 LP |
982 | r = socket_bind_to_ifindex(fd, LOOPBACK_IFINDEX); |
983 | if (r < 0) | |
984 | return r; | |
b30bf55d | 985 | |
d491917c ZJS |
986 | r = setsockopt_int(fd, IPPROTO_IP, IP_TTL, 1); |
987 | if (r < 0) | |
988 | return r; | |
989 | ||
424e490b ZJS |
990 | if (bind(fd, &sa.sa, sizeof(sa.in)) < 0) |
991 | return -errno; | |
b30bf55d | 992 | |
d491917c ZJS |
993 | if (type == SOCK_STREAM && |
994 | listen(fd, SOMAXCONN) < 0) | |
995 | return -errno; | |
996 | ||
997 | r = sd_event_add_io(m->event, event_source, fd, EPOLLIN, | |
998 | type == SOCK_DGRAM ? on_dns_stub_packet : on_dns_stub_stream, | |
999 | m); | |
b30bf55d | 1000 | if (r < 0) |
424e490b | 1001 | return r; |
b30bf55d | 1002 | |
d491917c | 1003 | r = sd_event_source_set_io_fd_own(*event_source, true); |
7216a3b5 YW |
1004 | if (r < 0) |
1005 | return r; | |
1006 | ||
d491917c ZJS |
1007 | (void) sd_event_source_set_description(*event_source, |
1008 | type == SOCK_DGRAM ? "dns-stub-udp" : "dns-stub-tcp"); | |
b30bf55d | 1009 | |
7216a3b5 | 1010 | return TAKE_FD(fd); |
b30bf55d LP |
1011 | } |
1012 | ||
b5febb3f | 1013 | static int manager_dns_stub_fd_extra(Manager *m, DnsStubListenerExtra *l, int type) { |
1f05101f SS |
1014 | _cleanup_free_ char *pretty = NULL; |
1015 | _cleanup_close_ int fd = -1; | |
ca8b62b5 | 1016 | union sockaddr_union sa; |
1f05101f SS |
1017 | int r; |
1018 | ||
0354029b | 1019 | assert(m); |
b5febb3f | 1020 | assert(IN_SET(type, SOCK_DGRAM, SOCK_STREAM)); |
0354029b | 1021 | |
d491917c ZJS |
1022 | if (!l) |
1023 | return manager_dns_stub_fd(m, type); | |
0354029b | 1024 | |
b5febb3f ZJS |
1025 | sd_event_source **event_source = type == SOCK_DGRAM ? &l->udp_event_source : &l->tcp_event_source; |
1026 | if (*event_source) | |
1027 | return sd_event_source_get_io_fd(*event_source); | |
1f05101f | 1028 | |
ca8b62b5 YW |
1029 | if (l->family == AF_INET) |
1030 | sa = (union sockaddr_union) { | |
1031 | .in.sin_family = l->family, | |
49ef064c | 1032 | .in.sin_port = htobe16(dns_stub_listener_extra_port(l)), |
ca8b62b5 YW |
1033 | .in.sin_addr = l->address.in, |
1034 | }; | |
1035 | else | |
1036 | sa = (union sockaddr_union) { | |
1037 | .in6.sin6_family = l->family, | |
49ef064c | 1038 | .in6.sin6_port = htobe16(dns_stub_listener_extra_port(l)), |
ca8b62b5 YW |
1039 | .in6.sin6_addr = l->address.in6, |
1040 | }; | |
1041 | ||
b5febb3f | 1042 | fd = socket(l->family, type | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); |
1f05101f SS |
1043 | if (fd < 0) { |
1044 | r = -errno; | |
1045 | goto fail; | |
1046 | } | |
1047 | ||
af8b1384 | 1048 | r = set_dns_stub_common_socket_options(fd, l->family); |
1f05101f SS |
1049 | if (r < 0) |
1050 | goto fail; | |
1051 | ||
69e3234d | 1052 | /* Do not set IP_TTL for extra DNS stub listeners, as the address may not be local and in that case |
b5febb3f ZJS |
1053 | * people may want ttl > 1. */ |
1054 | ||
5d0fe423 | 1055 | r = socket_set_freebind(fd, l->family, true); |
b5febb3f ZJS |
1056 | if (r < 0) |
1057 | goto fail; | |
1058 | ||
ca8b62b5 | 1059 | if (bind(fd, &sa.sa, SOCKADDR_LEN(sa)) < 0) { |
1f05101f SS |
1060 | r = -errno; |
1061 | goto fail; | |
1062 | } | |
1063 | ||
b5febb3f ZJS |
1064 | if (type == SOCK_STREAM && |
1065 | listen(fd, SOMAXCONN) < 0) { | |
1066 | r = -errno; | |
1067 | goto fail; | |
1068 | } | |
1069 | ||
1070 | r = sd_event_add_io(m->event, event_source, fd, EPOLLIN, | |
1071 | type == SOCK_DGRAM ? on_dns_stub_packet_extra : on_dns_stub_stream_extra, | |
1072 | l); | |
1f05101f SS |
1073 | if (r < 0) |
1074 | goto fail; | |
1075 | ||
b5febb3f | 1076 | r = sd_event_source_set_io_fd_own(*event_source, true); |
7216a3b5 YW |
1077 | if (r < 0) |
1078 | goto fail; | |
1079 | ||
b5febb3f ZJS |
1080 | (void) sd_event_source_set_description(*event_source, |
1081 | type == SOCK_DGRAM ? "dns-stub-udp-extra" : "dns-stub-tcp-extra"); | |
1f05101f SS |
1082 | |
1083 | if (DEBUG_LOGGING) { | |
ca8b62b5 | 1084 | (void) in_addr_port_to_string(l->family, &l->address, l->port, &pretty); |
b5febb3f ZJS |
1085 | log_debug("Listening on %s socket %s.", |
1086 | type == SOCK_DGRAM ? "UDP" : "TCP", | |
1087 | strnull(pretty)); | |
1f05101f SS |
1088 | } |
1089 | ||
7216a3b5 | 1090 | return TAKE_FD(fd); |
1f05101f | 1091 | |
b4b7ea1b | 1092 | fail: |
1c17bcb3 | 1093 | assert(r < 0); |
ca8b62b5 | 1094 | (void) in_addr_port_to_string(l->family, &l->address, l->port, &pretty); |
b5febb3f ZJS |
1095 | return log_warning_errno(r, |
1096 | r == -EADDRINUSE ? "Another process is already listening on %s socket %s: %m" : | |
1097 | "Failed to listen on %s socket %s: %m", | |
1098 | type == SOCK_DGRAM ? "UDP" : "TCP", | |
1099 | strnull(pretty)); | |
1f05101f SS |
1100 | } |
1101 | ||
b30bf55d | 1102 | int manager_dns_stub_start(Manager *m) { |
424e490b | 1103 | const char *t = "UDP"; |
01b0669e | 1104 | int r = 0; |
b30bf55d LP |
1105 | |
1106 | assert(m); | |
1107 | ||
d5da7707 ZJS |
1108 | if (m->dns_stub_listener_mode == DNS_STUB_LISTENER_NO) |
1109 | log_debug("Not creating stub listener."); | |
1110 | else | |
1111 | log_debug("Creating stub listener using %s.", | |
1112 | m->dns_stub_listener_mode == DNS_STUB_LISTENER_UDP ? "UDP" : | |
1113 | m->dns_stub_listener_mode == DNS_STUB_LISTENER_TCP ? "TCP" : | |
1114 | "UDP/TCP"); | |
1115 | ||
88d2cb7c | 1116 | if (FLAGS_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_UDP)) |
d491917c | 1117 | r = manager_dns_stub_fd(m, SOCK_DGRAM); |
b30bf55d | 1118 | |
424e490b | 1119 | if (r >= 0 && |
88d2cb7c | 1120 | FLAGS_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_TCP)) { |
424e490b | 1121 | t = "TCP"; |
d491917c | 1122 | r = manager_dns_stub_fd(m, SOCK_STREAM); |
1ae43295 | 1123 | } |
b30bf55d | 1124 | |
0f4db364 | 1125 | if (IN_SET(r, -EADDRINUSE, -EPERM)) { |
d491917c ZJS |
1126 | log_warning_errno(r, |
1127 | r == -EADDRINUSE ? "Another process is already listening on %s socket 127.0.0.53:53.\n" | |
1128 | "Turning off local DNS stub support." : | |
1129 | "Failed to listen on %s socket 127.0.0.53:53: %m.\n" | |
1130 | "Turning off local DNS stub support.", | |
1131 | t); | |
424e490b ZJS |
1132 | manager_dns_stub_stop(m); |
1133 | } else if (r < 0) | |
1134 | return log_error_errno(r, "Failed to listen on %s socket 127.0.0.53:53: %m", t); | |
b30bf55d | 1135 | |
1f05101f | 1136 | if (!ordered_set_isempty(m->dns_extra_stub_listeners)) { |
36aaabc3 | 1137 | DnsStubListenerExtra *l; |
1f05101f | 1138 | |
dce65cd4 | 1139 | log_debug("Creating extra stub listeners."); |
1f05101f | 1140 | |
90e74a66 | 1141 | ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners) { |
7314b397 | 1142 | if (FLAGS_SET(l->mode, DNS_STUB_LISTENER_UDP)) |
b5febb3f | 1143 | (void) manager_dns_stub_fd_extra(m, l, SOCK_DGRAM); |
7314b397 | 1144 | if (FLAGS_SET(l->mode, DNS_STUB_LISTENER_TCP)) |
b5febb3f | 1145 | (void) manager_dns_stub_fd_extra(m, l, SOCK_STREAM); |
7314b397 | 1146 | } |
1f05101f SS |
1147 | } |
1148 | ||
b30bf55d LP |
1149 | return 0; |
1150 | } | |
1151 | ||
1152 | void manager_dns_stub_stop(Manager *m) { | |
1153 | assert(m); | |
1154 | ||
1155 | m->dns_stub_udp_event_source = sd_event_source_unref(m->dns_stub_udp_event_source); | |
1156 | m->dns_stub_tcp_event_source = sd_event_source_unref(m->dns_stub_tcp_event_source); | |
b30bf55d | 1157 | } |
ae8f0ec3 LP |
1158 | |
1159 | static const char* const dns_stub_listener_mode_table[_DNS_STUB_LISTENER_MODE_MAX] = { | |
1160 | [DNS_STUB_LISTENER_NO] = "no", | |
1161 | [DNS_STUB_LISTENER_UDP] = "udp", | |
1162 | [DNS_STUB_LISTENER_TCP] = "tcp", | |
1163 | [DNS_STUB_LISTENER_YES] = "yes", | |
1164 | }; | |
1165 | DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(dns_stub_listener_mode, DnsStubListenerMode, DNS_STUB_LISTENER_YES); |