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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
b30bf55d | 2 | |
ca8b62b5 | 3 | #include <net/if_arp.h> |
8624f128 | 4 | #include <netinet/tcp.h> |
ca8b62b5 | 5 | |
0398c084 | 6 | #include "capability-util.h" |
4ff9bc2e | 7 | #include "errno-util.h" |
b30bf55d | 8 | #include "fd-util.h" |
ef118d00 | 9 | #include "missing_network.h" |
af8b1384 | 10 | #include "missing_socket.h" |
b30bf55d | 11 | #include "resolved-dns-stub.h" |
1f05101f | 12 | #include "socket-netlink.h" |
b30bf55d | 13 | #include "socket-util.h" |
4a6eb824 | 14 | #include "stdio-util.h" |
ae8f0ec3 | 15 | #include "string-table.h" |
b30bf55d LP |
16 | |
17 | /* The MTU of the loopback device is 64K on Linux, advertise that as maximum datagram size, but subtract the Ethernet, | |
18 | * IP and UDP header sizes */ | |
19 | #define ADVERTISE_DATAGRAM_SIZE_MAX (65536U-14U-20U-8U) | |
20 | ||
b370adb5 LP |
21 | /* On the extra stubs, use a more conservative choice */ |
22 | #define ADVERTISE_EXTRA_DATAGRAM_SIZE_MAX DNS_PACKET_UNICAST_SIZE_LARGE_MAX | |
23 | ||
b5febb3f | 24 | static int manager_dns_stub_fd_extra(Manager *m, DnsStubListenerExtra *l, int type); |
a8d09063 | 25 | static int manager_dns_stub_fd(Manager *m, int family, const union in_addr_union *listen_address, int type); |
0354029b | 26 | |
ae8f0ec3 LP |
27 | static void dns_stub_listener_extra_hash_func(const DnsStubListenerExtra *a, struct siphash *state) { |
28 | assert(a); | |
29 | ||
30 | siphash24_compress(&a->mode, sizeof(a->mode), state); | |
31 | siphash24_compress(&a->family, sizeof(a->family), state); | |
32 | siphash24_compress(&a->address, FAMILY_ADDRESS_SIZE(a->family), state); | |
33 | siphash24_compress(&a->port, sizeof(a->port), state); | |
34 | } | |
35 | ||
36 | static int dns_stub_listener_extra_compare_func(const DnsStubListenerExtra *a, const DnsStubListenerExtra *b) { | |
37 | int r; | |
38 | ||
39 | assert(a); | |
40 | assert(b); | |
41 | ||
42 | r = CMP(a->mode, b->mode); | |
43 | if (r != 0) | |
44 | return r; | |
45 | ||
46 | r = CMP(a->family, b->family); | |
47 | if (r != 0) | |
48 | return r; | |
49 | ||
50 | r = memcmp(&a->address, &b->address, FAMILY_ADDRESS_SIZE(a->family)); | |
51 | if (r != 0) | |
52 | return r; | |
53 | ||
54 | return CMP(a->port, b->port); | |
55 | } | |
56 | ||
57 | DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR( | |
58 | dns_stub_listener_extra_hash_ops, | |
59 | DnsStubListenerExtra, | |
60 | dns_stub_listener_extra_hash_func, | |
61 | dns_stub_listener_extra_compare_func, | |
62 | dns_stub_listener_extra_free); | |
63 | ||
0354029b LP |
64 | int dns_stub_listener_extra_new( |
65 | Manager *m, | |
66 | DnsStubListenerExtra **ret) { | |
ae8f0ec3 | 67 | |
36aaabc3 | 68 | DnsStubListenerExtra *l; |
1f05101f | 69 | |
0354029b | 70 | l = new(DnsStubListenerExtra, 1); |
1f05101f SS |
71 | if (!l) |
72 | return -ENOMEM; | |
73 | ||
0354029b LP |
74 | *l = (DnsStubListenerExtra) { |
75 | .manager = m, | |
76 | }; | |
1f05101f | 77 | |
0354029b | 78 | *ret = TAKE_PTR(l); |
1f05101f SS |
79 | return 0; |
80 | } | |
81 | ||
36aaabc3 | 82 | DnsStubListenerExtra *dns_stub_listener_extra_free(DnsStubListenerExtra *p) { |
bf22f231 YW |
83 | if (!p) |
84 | return NULL; | |
85 | ||
97935302 ZJS |
86 | p->udp_event_source = sd_event_source_disable_unref(p->udp_event_source); |
87 | p->tcp_event_source = sd_event_source_disable_unref(p->tcp_event_source); | |
bf22f231 | 88 | |
bde69bbd LP |
89 | hashmap_free(p->queries_by_packet); |
90 | ||
bf22f231 YW |
91 | return mfree(p); |
92 | } | |
93 | ||
bde69bbd LP |
94 | static void stub_packet_hash_func(const DnsPacket *p, struct siphash *state) { |
95 | assert(p); | |
96 | ||
97 | siphash24_compress(&p->protocol, sizeof(p->protocol), state); | |
98 | siphash24_compress(&p->family, sizeof(p->family), state); | |
99 | siphash24_compress(&p->sender, sizeof(p->sender), state); | |
100 | siphash24_compress(&p->ipproto, sizeof(p->ipproto), state); | |
101 | siphash24_compress(&p->sender_port, sizeof(p->sender_port), state); | |
102 | siphash24_compress(DNS_PACKET_HEADER(p), sizeof(DnsPacketHeader), state); | |
103 | ||
104 | /* We don't bother hashing the full packet here, just the header */ | |
105 | } | |
106 | ||
107 | static int stub_packet_compare_func(const DnsPacket *x, const DnsPacket *y) { | |
108 | int r; | |
109 | ||
110 | r = CMP(x->protocol, y->protocol); | |
111 | if (r != 0) | |
112 | return r; | |
113 | ||
114 | r = CMP(x->family, y->family); | |
115 | if (r != 0) | |
116 | return r; | |
117 | ||
118 | r = memcmp(&x->sender, &y->sender, sizeof(x->sender)); | |
119 | if (r != 0) | |
120 | return r; | |
121 | ||
122 | r = CMP(x->ipproto, y->ipproto); | |
123 | if (r != 0) | |
124 | return r; | |
125 | ||
126 | r = CMP(x->sender_port, y->sender_port); | |
127 | if (r != 0) | |
128 | return r; | |
129 | ||
130 | return memcmp(DNS_PACKET_HEADER(x), DNS_PACKET_HEADER(y), sizeof(DnsPacketHeader)); | |
131 | } | |
132 | ||
133 | DEFINE_HASH_OPS(stub_packet_hash_ops, DnsPacket, stub_packet_hash_func, stub_packet_compare_func); | |
134 | ||
5bd7ebb3 LP |
135 | static int reply_add_with_rrsig( |
136 | DnsAnswer **reply, | |
137 | DnsResourceRecord *rr, | |
138 | int ifindex, | |
139 | DnsAnswerFlags flags, | |
140 | DnsResourceRecord *rrsig, | |
141 | bool with_rrsig) { | |
142 | int r; | |
143 | ||
144 | assert(reply); | |
145 | assert(rr); | |
146 | ||
147 | r = dns_answer_add_extend(reply, rr, ifindex, flags, rrsig); | |
148 | if (r < 0) | |
149 | return r; | |
150 | ||
151 | if (with_rrsig && rrsig) { | |
152 | r = dns_answer_add_extend(reply, rrsig, ifindex, flags, NULL); | |
153 | if (r < 0) | |
154 | return r; | |
155 | } | |
156 | ||
157 | return 0; | |
158 | } | |
159 | ||
775ae354 LP |
160 | static int dns_stub_collect_answer_by_question( |
161 | DnsAnswer **reply, | |
51027656 | 162 | DnsAnswer *answer, |
775ae354 LP |
163 | DnsQuestion *question, |
164 | bool with_rrsig) { /* Add RRSIG RR matching each RR */ | |
b30bf55d | 165 | |
775ae354 | 166 | DnsAnswerItem *item; |
b30bf55d LP |
167 | int r; |
168 | ||
775ae354 | 169 | assert(reply); |
e8d23f92 | 170 | |
915ba31c | 171 | /* Copies all RRs from 'answer' into 'reply', if they match 'question'. */ |
4838dc4f | 172 | |
915ba31c | 173 | DNS_ANSWER_FOREACH_ITEM(item, answer) { |
5bd7ebb3 | 174 | |
915ba31c LP |
175 | /* We have a question, let's see if this RR matches it */ |
176 | r = dns_question_matches_rr(question, item->rr, NULL); | |
177 | if (r < 0) | |
178 | return r; | |
179 | if (!r) { | |
180 | /* Maybe there's a CNAME/DNAME in here? If so, that's an answer too */ | |
181 | r = dns_question_matches_cname_or_dname(question, item->rr, NULL); | |
4838dc4f LP |
182 | if (r < 0) |
183 | return r; | |
915ba31c LP |
184 | if (!r) |
185 | continue; | |
4838dc4f | 186 | } |
5bd7ebb3 | 187 | |
915ba31c LP |
188 | /* Mask the section info, we want the primary answers to always go without section |
189 | * info, so that it is added to the answer section when we synthesize a reply. */ | |
5bd7ebb3 | 190 | |
915ba31c LP |
191 | r = reply_add_with_rrsig( |
192 | reply, | |
193 | item->rr, | |
194 | item->ifindex, | |
195 | item->flags & ~DNS_ANSWER_MASK_SECTIONS, | |
196 | item->rrsig, | |
197 | with_rrsig); | |
198 | if (r < 0) | |
199 | return r; | |
e8d23f92 | 200 | } |
b30bf55d | 201 | |
775ae354 LP |
202 | return 0; |
203 | } | |
e8d23f92 | 204 | |
775ae354 LP |
205 | static int dns_stub_collect_answer_by_section( |
206 | DnsAnswer **reply, | |
207 | DnsAnswer *answer, | |
208 | DnsAnswerFlags section, | |
209 | DnsAnswer *exclude1, | |
210 | DnsAnswer *exclude2, | |
211 | bool with_dnssec) { /* Include DNSSEC RRs. RRSIG, NSEC, … */ | |
b30bf55d | 212 | |
775ae354 | 213 | DnsAnswerItem *item; |
775ae354 | 214 | int r; |
b30bf55d | 215 | |
775ae354 LP |
216 | assert(reply); |
217 | ||
218 | /* Copies all RRs from 'answer' into 'reply', if they originate from the specified section. Also, | |
219 | * avoid any RRs listed in 'exclude'. */ | |
220 | ||
221 | DNS_ANSWER_FOREACH_ITEM(item, answer) { | |
222 | ||
223 | if (dns_answer_contains(exclude1, item->rr) || | |
224 | dns_answer_contains(exclude2, item->rr)) | |
225 | continue; | |
226 | ||
227 | if (!with_dnssec && | |
228 | dns_type_is_dnssec(item->rr->key->type)) | |
229 | continue; | |
230 | ||
c4d98c3a | 231 | if (((item->flags ^ section) & DNS_ANSWER_MASK_SECTIONS) != 0) |
775ae354 LP |
232 | continue; |
233 | ||
5bd7ebb3 LP |
234 | r = reply_add_with_rrsig( |
235 | reply, | |
236 | item->rr, | |
237 | item->ifindex, | |
238 | item->flags, | |
239 | item->rrsig, | |
240 | with_dnssec); | |
b30bf55d LP |
241 | if (r < 0) |
242 | return r; | |
b30bf55d | 243 | } |
e8d23f92 | 244 | |
5bd7ebb3 | 245 | return 0; |
775ae354 LP |
246 | } |
247 | ||
248 | static int dns_stub_assign_sections( | |
249 | DnsQuery *q, | |
250 | DnsQuestion *question, | |
251 | bool edns0_do) { | |
252 | ||
253 | int r; | |
254 | ||
255 | assert(q); | |
256 | assert(question); | |
257 | ||
c6ebf89b LP |
258 | /* Let's assign the 'answer' RRs we collected to their respective sections in the reply datagram. We |
259 | * try to reproduce a section assignment similar to what the upstream DNS server responded to us. We | |
260 | * use the DNS_ANSWER_SECTION_xyz flags to match things up, which is where the original upstream's | |
261 | * packet section assignment is stored in the DnsAnswer object. Not all RRs in the 'answer' objects | |
262 | * come with section information though (for example, because they were synthesized locally, and not | |
263 | * from a DNS packet). To deal with that we extend the assignment logic a bit: anything from the | |
264 | * 'answer' object that directly matches the original question is always put in the ANSWER section, | |
265 | * regardless if it carries section info, or what that section info says. Then, anything from the | |
266 | * 'answer' objects that is from the ANSWER or AUTHORITY sections, and wasn't already added to the | |
267 | * ANSWER section is placed in the AUTHORITY section. Everything else from either object is added to | |
268 | * the ADDITIONAL section. */ | |
775ae354 LP |
269 | |
270 | /* Include all RRs that directly answer the question in the answer section */ | |
271 | r = dns_stub_collect_answer_by_question( | |
272 | &q->reply_answer, | |
273 | q->answer, | |
274 | question, | |
275 | edns0_do); | |
276 | if (r < 0) | |
277 | return r; | |
278 | ||
d451f0e8 | 279 | /* Include all RRs that originate from the authority sections, and aren't already listed in the |
775ae354 LP |
280 | * answer section, in the authority section */ |
281 | r = dns_stub_collect_answer_by_section( | |
282 | &q->reply_authoritative, | |
283 | q->answer, | |
d451f0e8 | 284 | DNS_ANSWER_SECTION_AUTHORITY, |
775ae354 LP |
285 | q->reply_answer, NULL, |
286 | edns0_do); | |
287 | if (r < 0) | |
288 | return r; | |
d451f0e8 LP |
289 | |
290 | /* Include all RRs that originate from the answer or additional sections in the additional section | |
291 | * (except if already listed in the other two sections). Also add all RRs with no section marking. */ | |
775ae354 | 292 | r = dns_stub_collect_answer_by_section( |
d451f0e8 | 293 | &q->reply_additional, |
775ae354 | 294 | q->answer, |
d451f0e8 LP |
295 | DNS_ANSWER_SECTION_ANSWER, |
296 | q->reply_answer, q->reply_authoritative, | |
775ae354 LP |
297 | edns0_do); |
298 | if (r < 0) | |
299 | return r; | |
775ae354 LP |
300 | r = dns_stub_collect_answer_by_section( |
301 | &q->reply_additional, | |
302 | q->answer, | |
303 | DNS_ANSWER_SECTION_ADDITIONAL, | |
304 | q->reply_answer, q->reply_authoritative, | |
305 | edns0_do); | |
306 | if (r < 0) | |
307 | return r; | |
308 | r = dns_stub_collect_answer_by_section( | |
309 | &q->reply_additional, | |
310 | q->answer, | |
311 | 0, | |
312 | q->reply_answer, q->reply_authoritative, | |
313 | edns0_do); | |
314 | if (r < 0) | |
315 | return r; | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | static int dns_stub_make_reply_packet( | |
321 | DnsPacket **ret, | |
322 | size_t max_size, | |
323 | DnsQuestion *q, | |
324 | bool *ret_truncated) { | |
325 | ||
326 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
327 | bool tc = false; | |
328 | int r; | |
329 | ||
330 | assert(ret); | |
331 | ||
332 | r = dns_packet_new(&p, DNS_PROTOCOL_DNS, 0, max_size); | |
333 | if (r < 0) | |
334 | return r; | |
335 | ||
336 | r = dns_packet_append_question(p, q); | |
337 | if (r == -EMSGSIZE) | |
338 | tc = true; | |
339 | else if (r < 0) | |
340 | return r; | |
341 | ||
51027656 | 342 | if (ret_truncated) |
775ae354 LP |
343 | *ret_truncated = tc; |
344 | else if (tc) | |
51027656 LP |
345 | return -EMSGSIZE; |
346 | ||
775ae354 | 347 | DNS_PACKET_HEADER(p)->qdcount = htobe16(dns_question_size(q)); |
e8d23f92 | 348 | |
775ae354 LP |
349 | *ret = TAKE_PTR(p); |
350 | return 0; | |
351 | } | |
352 | ||
353 | static int dns_stub_add_reply_packet_body( | |
354 | DnsPacket *p, | |
355 | DnsAnswer *answer, | |
356 | DnsAnswer *authoritative, | |
357 | DnsAnswer *additional, | |
358 | bool edns0_do, /* Client expects DNSSEC RRs? */ | |
359 | bool *truncated) { | |
360 | ||
361 | unsigned n_answer = 0, n_authoritative = 0, n_additional = 0; | |
362 | bool tc = false; | |
363 | int r; | |
364 | ||
365 | assert(p); | |
366 | ||
367 | /* Add the three sections to the packet. If the answer section doesn't fit we'll signal that as | |
368 | * truncation. If the authoritative section doesn't fit and we are in DNSSEC mode, also signal | |
369 | * truncation. In all other cases where things don't fit don't signal truncation, as for those cases | |
370 | * the dropped RRs should not be essential. */ | |
371 | ||
372 | r = dns_packet_append_answer(p, answer, &n_answer); | |
373 | if (r == -EMSGSIZE) | |
374 | tc = true; | |
375 | else if (r < 0) | |
376 | return r; | |
377 | else { | |
378 | r = dns_packet_append_answer(p, authoritative, &n_authoritative); | |
379 | if (r == -EMSGSIZE) { | |
380 | if (edns0_do) | |
381 | tc = true; | |
382 | } else if (r < 0) | |
383 | return r; | |
384 | else { | |
385 | r = dns_packet_append_answer(p, additional, &n_additional); | |
386 | if (r < 0 && r != -EMSGSIZE) | |
387 | return r; | |
388 | } | |
389 | } | |
390 | ||
391 | if (tc) { | |
392 | if (!truncated) | |
393 | return -EMSGSIZE; | |
394 | ||
395 | *truncated = true; | |
396 | } | |
397 | ||
398 | DNS_PACKET_HEADER(p)->ancount = htobe16(n_answer); | |
399 | DNS_PACKET_HEADER(p)->nscount = htobe16(n_authoritative); | |
400 | DNS_PACKET_HEADER(p)->arcount = htobe16(n_additional); | |
e8d23f92 LP |
401 | return 0; |
402 | } | |
403 | ||
4a6eb824 LP |
404 | static const char *nsid_string(void) { |
405 | static char buffer[SD_ID128_STRING_MAX + STRLEN(".resolved.systemd.io")] = ""; | |
406 | sd_id128_t id; | |
407 | int r; | |
408 | ||
409 | /* Let's generate a string that we can use as RFC5001 NSID identifier. The string shall identify us | |
410 | * as systemd-resolved, and return a different string for each resolved instance without leaking host | |
411 | * identity. Hence let's use a fixed suffix that identifies resolved, and a prefix generated from the | |
412 | * machine ID but from which the machine ID cannot be determined. | |
413 | * | |
414 | * Clients can use this to determine whether an answer is originating locally or is proxied from | |
415 | * upstream. */ | |
416 | ||
417 | if (!isempty(buffer)) | |
418 | return buffer; | |
419 | ||
420 | r = sd_id128_get_machine_app_specific( | |
421 | SD_ID128_MAKE(ed,d3,12,5d,16,b9,41,f9,a1,49,5f,ab,15,62,ab,27), | |
422 | &id); | |
423 | if (r < 0) { | |
b480543c | 424 | log_debug_errno(r, "Failed to determine machine ID, ignoring: %m"); |
4a6eb824 LP |
425 | return NULL; |
426 | } | |
427 | ||
428 | xsprintf(buffer, SD_ID128_FORMAT_STR ".resolved.systemd.io", SD_ID128_FORMAT_VAL(id)); | |
429 | return buffer; | |
430 | } | |
431 | ||
e8d23f92 LP |
432 | static int dns_stub_finish_reply_packet( |
433 | DnsPacket *p, | |
434 | uint16_t id, | |
435 | int rcode, | |
51027656 | 436 | bool tc, /* set the Truncated bit? */ |
4ad017cd | 437 | bool aa, /* set the Authoritative Answer bit? */ |
da846b30 | 438 | bool rd, /* set the Recursion Desired bit? */ |
e8d23f92 LP |
439 | bool add_opt, /* add an OPT RR to this packet? */ |
440 | bool edns0_do, /* set the EDNS0 DNSSEC OK bit? */ | |
b370adb5 | 441 | bool ad, /* set the DNSSEC authenticated data bit? */ |
775ae354 | 442 | bool cd, /* set the DNSSEC checking disabled bit? */ |
4a6eb824 LP |
443 | uint16_t max_udp_size, /* The maximum UDP datagram size to advertise to clients */ |
444 | bool nsid) { /* whether to add NSID */ | |
e8d23f92 LP |
445 | |
446 | int r; | |
447 | ||
448 | assert(p); | |
449 | ||
ff4caaae | 450 | if (add_opt) { |
4a6eb824 | 451 | r = dns_packet_append_opt(p, max_udp_size, edns0_do, /* include_rfc6975 = */ false, nsid ? nsid_string() : NULL, rcode, NULL); |
ff4caaae LP |
452 | if (r == -EMSGSIZE) /* Hit the size limit? then indicate truncation */ |
453 | tc = true; | |
454 | else if (r < 0) | |
455 | return r; | |
ff4caaae | 456 | } else { |
941dd294 LP |
457 | /* If the client can't to EDNS0, don't do DO either */ |
458 | edns0_do = false; | |
459 | ||
775ae354 | 460 | /* If we don't do EDNS, clamp the rcode to 4 bit */ |
941dd294 LP |
461 | if (rcode > 0xF) |
462 | rcode = DNS_RCODE_SERVFAIL; | |
463 | } | |
464 | ||
8c9c68b5 LP |
465 | /* Don't set the CD bit unless DO is on, too */ |
466 | if (!edns0_do) | |
775ae354 LP |
467 | cd = false; |
468 | ||
8c9c68b5 LP |
469 | /* Note that we allow the AD bit to be set even if client didn't signal DO, as per RFC 6840, section |
470 | * 5.7 */ | |
e8d23f92 LP |
471 | |
472 | DNS_PACKET_HEADER(p)->id = id; | |
473 | ||
474 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( | |
51027656 LP |
475 | 1 /* qr */, |
476 | 0 /* opcode */, | |
4ad017cd | 477 | aa /* aa */, |
51027656 | 478 | tc /* tc */, |
da846b30 | 479 | rd /* rd */, |
51027656 | 480 | 1 /* ra */, |
e8d23f92 | 481 | ad /* ad */, |
775ae354 | 482 | cd /* cd */, |
e8d23f92 | 483 | rcode)); |
b30bf55d | 484 | |
b30bf55d LP |
485 | return 0; |
486 | } | |
487 | ||
a8d09063 LP |
488 | static bool address_is_proxy(int family, const union in_addr_union *a) { |
489 | assert(a); | |
490 | ||
491 | /* Returns true if the specified address is the DNS "proxy" stub, i.e. where we unconditionally enable bypass mode */ | |
492 | ||
493 | if (family != AF_INET) | |
494 | return false; | |
495 | ||
496 | return be32toh(a->in.s_addr) == INADDR_DNS_PROXY_STUB; | |
497 | } | |
498 | ||
499 | static int find_socket_fd( | |
500 | Manager *m, | |
501 | DnsStubListenerExtra *l, | |
502 | int family, | |
503 | const union in_addr_union *listen_address, | |
504 | int type) { | |
505 | ||
506 | assert(m); | |
507 | ||
508 | /* Finds the right socket to use for sending. If we know the extra listener, otherwise go via the | |
509 | * address to send from */ | |
510 | if (l) | |
511 | return manager_dns_stub_fd_extra(m, l, type); | |
512 | ||
513 | return manager_dns_stub_fd(m, family, listen_address, type); | |
514 | } | |
515 | ||
0354029b LP |
516 | static int dns_stub_send( |
517 | Manager *m, | |
518 | DnsStubListenerExtra *l, | |
519 | DnsStream *s, | |
520 | DnsPacket *p, | |
521 | DnsPacket *reply) { | |
522 | ||
b30bf55d LP |
523 | int r; |
524 | ||
525 | assert(m); | |
526 | assert(p); | |
527 | assert(reply); | |
528 | ||
529 | if (s) | |
530 | r = dns_stream_write_packet(s, reply); | |
a8d09063 | 531 | else { |
dfa14e28 | 532 | int fd, ifindex; |
a8d09063 | 533 | |
de777ffa | 534 | fd = find_socket_fd(m, l, p->family, &p->destination, SOCK_DGRAM); |
a8d09063 LP |
535 | if (fd < 0) |
536 | return fd; | |
537 | ||
dfa14e28 BF |
538 | if (address_is_proxy(p->family, &p->destination)) |
539 | /* Force loopback iface if this is the loopback proxy stub | |
540 | * and ifindex was normalized to 0 by manager_recv(). */ | |
541 | ifindex = p->ifindex ?: LOOPBACK_IFINDEX; | |
542 | else | |
543 | /* Force loopback iface if this is the main listener stub. */ | |
544 | ifindex = l ? p->ifindex : LOOPBACK_IFINDEX; | |
545 | ||
a8d09063 LP |
546 | /* Note that it is essential here that we explicitly choose the source IP address for this |
547 | * packet. This is because otherwise the kernel will choose it automatically based on the | |
dfa14e28 | 548 | * routing table and will thus pick 127.0.0.1 rather than 127.0.0.53/54. */ |
0354029b | 549 | r = manager_send(m, |
a8d09063 | 550 | fd, |
dfa14e28 | 551 | ifindex, |
0354029b LP |
552 | p->family, &p->sender, p->sender_port, &p->destination, |
553 | reply); | |
a8d09063 | 554 | } |
b30bf55d LP |
555 | if (r < 0) |
556 | return log_debug_errno(r, "Failed to send reply packet: %m"); | |
557 | ||
558 | return 0; | |
559 | } | |
560 | ||
39005e18 LP |
561 | static int dns_stub_reply_with_edns0_do(DnsQuery *q) { |
562 | assert(q); | |
563 | ||
564 | /* Reply with DNSSEC DO set? Only if client supports it; and we did any DNSSEC verification | |
565 | * ourselves, or consider the data fully authenticated because we generated it locally, or the client | |
566 | * set cd */ | |
567 | ||
568 | return DNS_PACKET_DO(q->request_packet) && | |
569 | (q->answer_dnssec_result >= 0 || /* we did proper DNSSEC validation … */ | |
570 | dns_query_fully_authenticated(q) || /* … or we considered it authentic otherwise … */ | |
571 | DNS_PACKET_CD(q->request_packet)); /* … or client set CD */ | |
572 | } | |
573 | ||
5d7da51e LP |
574 | static void dns_stub_suppress_duplicate_section_rrs(DnsQuery *q) { |
575 | /* If we follow a CNAME/DNAME chain we might end up populating our sections with redundant RRs | |
576 | * because we built up the sections from multiple reply packets (one from each CNAME/DNAME chain | |
577 | * element). E.g. it could be that an RR that was included in the first reply's additional section | |
578 | * ends up being relevant as main answer in a subsequent reply in the chain. Let's clean this up, and | |
579 | * remove everything in the "higher priority" sections from the "lower priority" sections. | |
580 | * | |
581 | * Note that this removal matches by RR keys instead of the full RRs. This is because RRsets should | |
582 | * always end up in one section fully or not at all, but never be split among sections. | |
583 | * | |
584 | * Specifically: we remove ANSWER section RRs from the AUTHORITATIVE and ADDITIONAL sections, as well | |
585 | * as AUTHORITATIVE section RRs from the ADDITIONAL section. */ | |
586 | ||
587 | dns_answer_remove_by_answer_keys(&q->reply_authoritative, q->reply_answer); | |
588 | dns_answer_remove_by_answer_keys(&q->reply_additional, q->reply_answer); | |
589 | dns_answer_remove_by_answer_keys(&q->reply_additional, q->reply_authoritative); | |
590 | } | |
591 | ||
775ae354 LP |
592 | static int dns_stub_send_reply( |
593 | DnsQuery *q, | |
594 | int rcode) { | |
595 | ||
596 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; | |
597 | bool truncated, edns0_do; | |
598 | int r; | |
599 | ||
600 | assert(q); | |
601 | ||
39005e18 | 602 | edns0_do = dns_stub_reply_with_edns0_do(q); /* let's check if we shall reply with EDNS0 DO? */ |
775ae354 | 603 | |
775ae354 LP |
604 | r = dns_stub_make_reply_packet( |
605 | &reply, | |
606 | DNS_PACKET_PAYLOAD_SIZE_MAX(q->request_packet), | |
607 | q->request_packet->question, | |
608 | &truncated); | |
609 | if (r < 0) | |
610 | return log_debug_errno(r, "Failed to build reply packet: %m"); | |
611 | ||
5d7da51e LP |
612 | dns_stub_suppress_duplicate_section_rrs(q); |
613 | ||
775ae354 LP |
614 | r = dns_stub_add_reply_packet_body( |
615 | reply, | |
616 | q->reply_answer, | |
617 | q->reply_authoritative, | |
618 | q->reply_additional, | |
619 | edns0_do, | |
620 | &truncated); | |
621 | if (r < 0) | |
622 | return log_debug_errno(r, "Failed to append reply packet body: %m"); | |
623 | ||
624 | r = dns_stub_finish_reply_packet( | |
625 | reply, | |
626 | DNS_PACKET_ID(q->request_packet), | |
627 | rcode, | |
628 | truncated, | |
9ddf099f | 629 | dns_query_fully_authoritative(q), |
da846b30 | 630 | DNS_PACKET_RD(q->request_packet), |
775ae354 LP |
631 | !!q->request_packet->opt, |
632 | edns0_do, | |
b553abd8 | 633 | (DNS_PACKET_AD(q->request_packet) || DNS_PACKET_DO(q->request_packet)) && dns_query_fully_authenticated(q), |
775ae354 | 634 | DNS_PACKET_CD(q->request_packet), |
4a6eb824 LP |
635 | q->stub_listener_extra ? ADVERTISE_EXTRA_DATAGRAM_SIZE_MAX : ADVERTISE_DATAGRAM_SIZE_MAX, |
636 | dns_packet_has_nsid_request(q->request_packet) > 0 && !q->stub_listener_extra); | |
775ae354 LP |
637 | if (r < 0) |
638 | return log_debug_errno(r, "Failed to build failure packet: %m"); | |
639 | ||
640 | return dns_stub_send(q->manager, q->stub_listener_extra, q->request_stream, q->request_packet, reply); | |
641 | } | |
642 | ||
0354029b LP |
643 | static int dns_stub_send_failure( |
644 | Manager *m, | |
645 | DnsStubListenerExtra *l, | |
646 | DnsStream *s, | |
647 | DnsPacket *p, | |
648 | int rcode, | |
649 | bool authenticated) { | |
650 | ||
b30bf55d | 651 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; |
775ae354 | 652 | bool truncated; |
b30bf55d LP |
653 | int r; |
654 | ||
655 | assert(m); | |
656 | assert(p); | |
657 | ||
775ae354 LP |
658 | r = dns_stub_make_reply_packet( |
659 | &reply, | |
660 | DNS_PACKET_PAYLOAD_SIZE_MAX(p), | |
661 | p->question, | |
662 | &truncated); | |
e8d23f92 LP |
663 | if (r < 0) |
664 | return log_debug_errno(r, "Failed to make failure packet: %m"); | |
665 | ||
b370adb5 LP |
666 | r = dns_stub_finish_reply_packet( |
667 | reply, | |
668 | DNS_PACKET_ID(p), | |
669 | rcode, | |
775ae354 | 670 | truncated, |
4ad017cd | 671 | false, |
da846b30 | 672 | DNS_PACKET_RD(p), |
b370adb5 LP |
673 | !!p->opt, |
674 | DNS_PACKET_DO(p), | |
b553abd8 | 675 | (DNS_PACKET_AD(p) || DNS_PACKET_DO(p)) && authenticated, |
775ae354 | 676 | DNS_PACKET_CD(p), |
4a6eb824 LP |
677 | l ? ADVERTISE_EXTRA_DATAGRAM_SIZE_MAX : ADVERTISE_DATAGRAM_SIZE_MAX, |
678 | dns_packet_has_nsid_request(p) > 0 && !l); | |
b30bf55d LP |
679 | if (r < 0) |
680 | return log_debug_errno(r, "Failed to build failure packet: %m"); | |
681 | ||
0354029b | 682 | return dns_stub_send(m, l, s, p, reply); |
b30bf55d LP |
683 | } |
684 | ||
775ae354 LP |
685 | static int dns_stub_patch_bypass_reply_packet( |
686 | DnsPacket **ret, /* Where to place the patched packet */ | |
687 | DnsPacket *original, /* The packet to patch */ | |
688 | DnsPacket *request) { /* The packet the patched packet shall look like a reply to */ | |
689 | _cleanup_(dns_packet_unrefp) DnsPacket *c = NULL; | |
690 | int r; | |
691 | ||
692 | assert(ret); | |
693 | assert(original); | |
694 | assert(request); | |
695 | ||
696 | r = dns_packet_dup(&c, original); | |
697 | if (r < 0) | |
698 | return r; | |
699 | ||
700 | /* Extract the packet, so that we know where the OPT field is */ | |
701 | r = dns_packet_extract(c); | |
702 | if (r < 0) | |
703 | return r; | |
704 | ||
705 | /* Copy over the original client request ID, so that we can make the upstream query look like our own reply. */ | |
706 | DNS_PACKET_HEADER(c)->id = DNS_PACKET_HEADER(request)->id; | |
707 | ||
708 | /* Patch in our own maximum datagram size, if EDNS0 was on */ | |
709 | r = dns_packet_patch_max_udp_size(c, ADVERTISE_DATAGRAM_SIZE_MAX); | |
710 | if (r < 0) | |
711 | return r; | |
712 | ||
713 | /* Lower all TTLs by the time passed since we received the datagram. */ | |
714 | if (timestamp_is_set(original->timestamp)) { | |
715 | r = dns_packet_patch_ttls(c, original->timestamp); | |
716 | if (r < 0) | |
717 | return r; | |
718 | } | |
719 | ||
720 | /* Our upstream connection might have supported larger DNS requests than our downstream one, hence | |
721 | * set the TC bit if our reply is larger than what the client supports, and truncate. */ | |
722 | if (c->size > DNS_PACKET_PAYLOAD_SIZE_MAX(request)) { | |
723 | log_debug("Artificially truncating stub response, as advertised size of client is smaller than upstream one."); | |
724 | dns_packet_truncate(c, DNS_PACKET_PAYLOAD_SIZE_MAX(request)); | |
725 | DNS_PACKET_HEADER(c)->flags = htobe16(be16toh(DNS_PACKET_HEADER(c)->flags) | DNS_PACKET_FLAG_TC); | |
726 | } | |
727 | ||
728 | *ret = TAKE_PTR(c); | |
729 | return 0; | |
730 | } | |
731 | ||
c704288c YW |
732 | static void dns_stub_query_complete(DnsQuery *query) { |
733 | _cleanup_(dns_query_freep) DnsQuery *q = query; | |
b30bf55d LP |
734 | int r; |
735 | ||
736 | assert(q); | |
775ae354 | 737 | assert(q->request_packet); |
b30bf55d | 738 | |
775ae354 LP |
739 | if (q->question_bypass) { |
740 | /* This is a bypass reply. If so, let's propagate the upstream packet, if we have it and it | |
741 | * is regular DNS. (We can't do this if the upstream packet is LLMNR or mDNS, since the | |
742 | * packets are not 100% compatible.) */ | |
b30bf55d | 743 | |
775ae354 LP |
744 | if (q->answer_full_packet && |
745 | q->answer_full_packet->protocol == DNS_PROTOCOL_DNS) { | |
746 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; | |
e8d23f92 | 747 | |
775ae354 LP |
748 | r = dns_stub_patch_bypass_reply_packet(&reply, q->answer_full_packet, q->request_packet); |
749 | if (r < 0) | |
750 | log_debug_errno(r, "Failed to patch bypass reply packet: %m"); | |
751 | else | |
752 | (void) dns_stub_send(q->manager, q->stub_listener_extra, q->request_stream, q->request_packet, reply); | |
753 | ||
775ae354 | 754 | return; |
e8d23f92 | 755 | } |
775ae354 | 756 | } |
b30bf55d | 757 | |
b97fc571 LP |
758 | /* Take all data from the current reply, and merge it into the three reply sections we are building |
759 | * up. We do this before processing CNAME redirects, so that we gradually build up our sections, and | |
760 | * and keep adding all RRs in the CNAME chain. */ | |
761 | r = dns_stub_assign_sections( | |
762 | q, | |
a7c0291c | 763 | dns_query_question_for_protocol(q, DNS_PROTOCOL_DNS), |
b97fc571 | 764 | dns_stub_reply_with_edns0_do(q)); |
c704288c YW |
765 | if (r < 0) |
766 | return (void) log_debug_errno(r, "Failed to assign sections: %m"); | |
2f4d8e57 | 767 | |
775ae354 LP |
768 | switch (q->state) { |
769 | ||
915ba31c LP |
770 | case DNS_TRANSACTION_SUCCESS: { |
771 | bool first = true; | |
772 | ||
773 | for (;;) { | |
774 | int cname_result; | |
775 | ||
776 | cname_result = dns_query_process_cname_one(q); | |
777 | if (cname_result == -ELOOP) { /* CNAME loop, let's send what we already have */ | |
fca212b0 | 778 | log_debug("Detected CNAME loop, returning what we already have."); |
915ba31c LP |
779 | (void) dns_stub_send_reply(q, q->answer_rcode); |
780 | break; | |
781 | } | |
782 | if (cname_result < 0) { | |
783 | log_debug_errno(cname_result, "Failed to process CNAME: %m"); | |
784 | break; | |
785 | } | |
786 | ||
787 | if (cname_result == DNS_QUERY_NOMATCH) { | |
788 | /* This answer doesn't contain any RR that would answer our question | |
789 | * positively, i.e. neither directly nor via CNAME. */ | |
790 | ||
791 | if (first) /* We never followed a CNAME and the answer doesn't match our | |
792 | * question at all? Then this is final, the empty answer is the | |
793 | * answer. */ | |
794 | break; | |
795 | ||
796 | /* Otherwise, we already followed a CNAME once within this packet, and the | |
797 | * packet doesn't answer our question. In that case let's restart the query, | |
798 | * now with the redirected question. We'll */ | |
799 | r = dns_query_go(q); | |
c704288c YW |
800 | if (r < 0) |
801 | return (void) log_debug_errno(r, "Failed to restart query: %m"); | |
915ba31c | 802 | |
c704288c | 803 | TAKE_PTR(q); |
915ba31c LP |
804 | return; |
805 | } | |
806 | ||
807 | r = dns_stub_assign_sections( | |
808 | q, | |
809 | dns_query_question_for_protocol(q, DNS_PROTOCOL_DNS), | |
810 | dns_stub_reply_with_edns0_do(q)); | |
c704288c YW |
811 | if (r < 0) |
812 | return (void) log_debug_errno(r, "Failed to assign sections: %m"); | |
915ba31c LP |
813 | |
814 | if (cname_result == DNS_QUERY_MATCH) /* A match? Then we are done, let's return what we got */ | |
815 | break; | |
816 | ||
817 | /* We followed a CNAME. and collected the RRs that answer the redirected question | |
818 | * successfully. Let's not try to do this again. */ | |
819 | assert(cname_result == DNS_QUERY_CNAME); | |
820 | first = false; | |
b97fc571 | 821 | } |
b97fc571 LP |
822 | |
823 | _fallthrough_; | |
915ba31c | 824 | } |
b97fc571 | 825 | |
b30bf55d | 826 | case DNS_TRANSACTION_RCODE_FAILURE: |
775ae354 | 827 | (void) dns_stub_send_reply(q, q->answer_rcode); |
b30bf55d LP |
828 | break; |
829 | ||
830 | case DNS_TRANSACTION_NOT_FOUND: | |
775ae354 | 831 | (void) dns_stub_send_reply(q, DNS_RCODE_NXDOMAIN); |
b30bf55d LP |
832 | break; |
833 | ||
834 | case DNS_TRANSACTION_TIMEOUT: | |
835 | case DNS_TRANSACTION_ATTEMPTS_MAX_REACHED: | |
836 | /* Propagate a timeout as a no packet, i.e. that the client also gets a timeout */ | |
837 | break; | |
838 | ||
839 | case DNS_TRANSACTION_NO_SERVERS: | |
840 | case DNS_TRANSACTION_INVALID_REPLY: | |
841 | case DNS_TRANSACTION_ERRNO: | |
842 | case DNS_TRANSACTION_ABORTED: | |
843 | case DNS_TRANSACTION_DNSSEC_FAILED: | |
844 | case DNS_TRANSACTION_NO_TRUST_ANCHOR: | |
845 | case DNS_TRANSACTION_RR_TYPE_UNSUPPORTED: | |
846 | case DNS_TRANSACTION_NETWORK_DOWN: | |
775ae354 | 847 | case DNS_TRANSACTION_NO_SOURCE: |
49ef064c | 848 | case DNS_TRANSACTION_STUB_LOOP: |
775ae354 | 849 | (void) dns_stub_send_reply(q, DNS_RCODE_SERVFAIL); |
b30bf55d LP |
850 | break; |
851 | ||
852 | case DNS_TRANSACTION_NULL: | |
853 | case DNS_TRANSACTION_PENDING: | |
854 | case DNS_TRANSACTION_VALIDATING: | |
855 | default: | |
04499a70 | 856 | assert_not_reached(); |
b30bf55d | 857 | } |
b30bf55d LP |
858 | } |
859 | ||
860 | static int dns_stub_stream_complete(DnsStream *s, int error) { | |
861 | assert(s); | |
862 | ||
b412af57 LP |
863 | log_debug_errno(error, "DNS TCP connection terminated, destroying queries: %m"); |
864 | ||
865 | for (;;) { | |
866 | DnsQuery *q; | |
867 | ||
868 | q = set_first(s->queries); | |
869 | if (!q) | |
870 | break; | |
b30bf55d | 871 | |
b412af57 LP |
872 | dns_query_free(q); |
873 | } | |
b30bf55d | 874 | |
b412af57 LP |
875 | /* This drops the implicit ref we keep around since it was allocated, as incoming stub connections |
876 | * should be kept as long as the client wants to. */ | |
877 | dns_stream_unref(s); | |
b30bf55d LP |
878 | return 0; |
879 | } | |
880 | ||
0354029b | 881 | static void dns_stub_process_query(Manager *m, DnsStubListenerExtra *l, DnsStream *s, DnsPacket *p) { |
a8d09063 | 882 | uint64_t protocol_flags = SD_RESOLVED_PROTOCOLS_ALL; |
ceb17827 | 883 | _cleanup_(dns_query_freep) DnsQuery *q = NULL; |
bde69bbd LP |
884 | Hashmap **queries_by_packet; |
885 | DnsQuery *existing; | |
a8d09063 | 886 | bool bypass = false; |
b30bf55d LP |
887 | int r; |
888 | ||
889 | assert(m); | |
890 | assert(p); | |
891 | assert(p->protocol == DNS_PROTOCOL_DNS); | |
892 | ||
0354029b | 893 | if (!l && /* l == NULL if this is the main stub */ |
a8d09063 | 894 | !address_is_proxy(p->family, &p->destination) && /* don't restrict needlessly for 127.0.0.54 */ |
d1fb8cda YW |
895 | (in_addr_is_localhost(p->family, &p->sender) <= 0 || |
896 | in_addr_is_localhost(p->family, &p->destination) <= 0)) { | |
565147b7 | 897 | log_warning("Got packet on unexpected (i.e. non-localhost) IP range, ignoring."); |
ceb17827 | 898 | return; |
b30bf55d LP |
899 | } |
900 | ||
a9fd8837 LP |
901 | if (manager_packet_from_our_transaction(m, p)) { |
902 | log_debug("Got our own packet looped back, ignoring."); | |
903 | return; | |
904 | } | |
905 | ||
bde69bbd LP |
906 | queries_by_packet = l ? &l->queries_by_packet : &m->stub_queries_by_packet; |
907 | existing = hashmap_get(*queries_by_packet, p); | |
908 | if (existing && dns_packet_equal(existing->request_packet, p)) { | |
909 | log_debug("Got repeat packet from client, ignoring."); | |
910 | return; | |
911 | } | |
912 | ||
b30bf55d LP |
913 | r = dns_packet_extract(p); |
914 | if (r < 0) { | |
915 | log_debug_errno(r, "Failed to extract resources from incoming packet, ignoring packet: %m"); | |
0354029b | 916 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_FORMERR, false); |
ceb17827 | 917 | return; |
b30bf55d LP |
918 | } |
919 | ||
920 | if (!DNS_PACKET_VERSION_SUPPORTED(p)) { | |
921 | log_debug("Got EDNS OPT field with unsupported version number."); | |
0354029b | 922 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_BADVERS, false); |
ceb17827 | 923 | return; |
b30bf55d LP |
924 | } |
925 | ||
ab715ddb | 926 | if (dns_type_is_obsolete(dns_question_first_key(p->question)->type)) { |
b30bf55d | 927 | log_debug("Got message with obsolete key type, refusing."); |
30ee7071 | 928 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_REFUSED, false); |
ceb17827 | 929 | return; |
b30bf55d LP |
930 | } |
931 | ||
d4fd7fb5 | 932 | if (dns_type_is_zone_transfer(dns_question_first_key(p->question)->type)) { |
b30bf55d | 933 | log_debug("Got request for zone transfer, refusing."); |
30ee7071 | 934 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_REFUSED, false); |
ceb17827 | 935 | return; |
b30bf55d LP |
936 | } |
937 | ||
938 | if (!DNS_PACKET_RD(p)) { | |
939 | /* If the "rd" bit is off (i.e. recursion was not requested), then refuse operation */ | |
940 | log_debug("Got request with recursion disabled, refusing."); | |
0354029b | 941 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_REFUSED, false); |
ceb17827 | 942 | return; |
b30bf55d LP |
943 | } |
944 | ||
bde69bbd LP |
945 | r = hashmap_ensure_allocated(queries_by_packet, &stub_packet_hash_ops); |
946 | if (r < 0) { | |
947 | log_oom(); | |
948 | return; | |
949 | } | |
950 | ||
a8d09063 LP |
951 | if (address_is_proxy(p->family, &p->destination)) { |
952 | _cleanup_free_ char *dipa = NULL; | |
953 | ||
954 | r = in_addr_to_string(p->family, &p->destination, &dipa); | |
e1158539 LP |
955 | if (r < 0) |
956 | return (void) log_error_errno(r, "Failed to format destination address: %m"); | |
a8d09063 LP |
957 | |
958 | log_debug("Got request to DNS proxy address 127.0.0.54, enabling bypass logic."); | |
959 | bypass = true; | |
960 | protocol_flags = SD_RESOLVED_DNS|SD_RESOLVED_NO_ZONE; /* Turn off mDNS/LLMNR for proxy stub. */ | |
961 | } else if ((DNS_PACKET_DO(p) && DNS_PACKET_CD(p))) { | |
775ae354 | 962 | log_debug("Got request with DNSSEC checking disabled, enabling bypass logic."); |
a8d09063 LP |
963 | bypass = true; |
964 | } | |
775ae354 | 965 | |
a8d09063 | 966 | if (bypass) |
775ae354 | 967 | r = dns_query_new(m, &q, NULL, NULL, p, 0, |
a8d09063 | 968 | protocol_flags| |
775ae354 LP |
969 | SD_RESOLVED_NO_CNAME| |
970 | SD_RESOLVED_NO_SEARCH| | |
971 | SD_RESOLVED_NO_VALIDATE| | |
972 | SD_RESOLVED_REQUIRE_PRIMARY| | |
973 | SD_RESOLVED_CLAMP_TTL); | |
a8d09063 | 974 | else |
775ae354 | 975 | r = dns_query_new(m, &q, p->question, p->question, NULL, 0, |
a8d09063 | 976 | protocol_flags| |
775ae354 | 977 | SD_RESOLVED_NO_SEARCH| |
2f4d8e57 | 978 | (DNS_PACKET_DO(p) ? SD_RESOLVED_REQUIRE_PRIMARY : 0)| |
775ae354 | 979 | SD_RESOLVED_CLAMP_TTL); |
b30bf55d LP |
980 | if (r < 0) { |
981 | log_error_errno(r, "Failed to generate query object: %m"); | |
0354029b | 982 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_SERVFAIL, false); |
ceb17827 | 983 | return; |
b30bf55d LP |
984 | } |
985 | ||
775ae354 LP |
986 | q->request_packet = dns_packet_ref(p); |
987 | q->request_stream = dns_stream_ref(s); /* make sure the stream stays around until we can send a reply through it */ | |
0354029b | 988 | q->stub_listener_extra = l; |
b30bf55d LP |
989 | q->complete = dns_stub_query_complete; |
990 | ||
991 | if (s) { | |
b412af57 LP |
992 | /* Remember which queries belong to this stream, so that we can cancel them when the stream |
993 | * is disconnected early */ | |
994 | ||
ceb17827 | 995 | r = set_ensure_put(&s->queries, NULL, q); |
b412af57 LP |
996 | if (r < 0) { |
997 | log_oom(); | |
ceb17827 | 998 | return; |
b412af57 | 999 | } |
ceb17827 | 1000 | assert(r > 0); |
b30bf55d LP |
1001 | } |
1002 | ||
bde69bbd LP |
1003 | /* Add the query to the hash table we use to determine repeat packets now. We don't care about |
1004 | * failures here, since in the worst case we'll not recognize duplicate incoming requests, which | |
1005 | * isn't particularly bad. */ | |
1006 | (void) hashmap_put(*queries_by_packet, q->request_packet, q); | |
1007 | ||
b30bf55d LP |
1008 | r = dns_query_go(q); |
1009 | if (r < 0) { | |
1010 | log_error_errno(r, "Failed to start query: %m"); | |
0354029b | 1011 | dns_stub_send_failure(m, l, s, p, DNS_RCODE_SERVFAIL, false); |
ceb17827 | 1012 | return; |
b30bf55d LP |
1013 | } |
1014 | ||
52e63427 | 1015 | log_debug("Processing query..."); |
ceb17827 | 1016 | TAKE_PTR(q); |
b30bf55d LP |
1017 | } |
1018 | ||
0354029b | 1019 | static int on_dns_stub_packet_internal(sd_event_source *s, int fd, uint32_t revents, Manager *m, DnsStubListenerExtra *l) { |
b30bf55d | 1020 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
b30bf55d LP |
1021 | int r; |
1022 | ||
1023 | r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p); | |
1024 | if (r <= 0) | |
1025 | return r; | |
1026 | ||
1027 | if (dns_packet_validate_query(p) > 0) { | |
1028 | log_debug("Got DNS stub UDP query packet for id %u", DNS_PACKET_ID(p)); | |
1029 | ||
0354029b | 1030 | dns_stub_process_query(m, l, NULL, p); |
b30bf55d LP |
1031 | } else |
1032 | log_debug("Invalid DNS stub UDP packet, ignoring."); | |
1033 | ||
1034 | return 0; | |
1035 | } | |
1036 | ||
d1fb8cda | 1037 | static int on_dns_stub_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
0354029b | 1038 | return on_dns_stub_packet_internal(s, fd, revents, userdata, NULL); |
d1fb8cda YW |
1039 | } |
1040 | ||
1041 | static int on_dns_stub_packet_extra(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
99534007 | 1042 | DnsStubListenerExtra *l = ASSERT_PTR(userdata); |
0354029b LP |
1043 | |
1044 | return on_dns_stub_packet_internal(s, fd, revents, l->manager, l); | |
d1fb8cda YW |
1045 | } |
1046 | ||
624f907e | 1047 | static int on_dns_stub_stream_packet(DnsStream *s, DnsPacket *p) { |
e4bed40f | 1048 | assert(s); |
624f907e | 1049 | assert(s->manager); |
e4bed40f ZJS |
1050 | assert(p); |
1051 | ||
1052 | if (dns_packet_validate_query(p) > 0) { | |
1053 | log_debug("Got DNS stub TCP query packet for id %u", DNS_PACKET_ID(p)); | |
1054 | ||
1055 | dns_stub_process_query(s->manager, s->stub_listener_extra, s, p); | |
1056 | } else | |
1057 | log_debug("Invalid DNS stub TCP packet, ignoring."); | |
1058 | ||
1059 | return 0; | |
1060 | } | |
1061 | ||
1062 | static int on_dns_stub_stream_internal(sd_event_source *s, int fd, uint32_t revents, Manager *m, DnsStubListenerExtra *l) { | |
1063 | DnsStream *stream; | |
1064 | int cfd, r; | |
1065 | ||
1066 | cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); | |
1067 | if (cfd < 0) { | |
1068 | if (ERRNO_IS_ACCEPT_AGAIN(errno)) | |
1069 | return 0; | |
1070 | ||
1071 | return -errno; | |
1072 | } | |
1073 | ||
18230451 YW |
1074 | r = dns_stream_new(m, &stream, DNS_STREAM_STUB, DNS_PROTOCOL_DNS, cfd, NULL, |
1075 | on_dns_stub_stream_packet, dns_stub_stream_complete, DNS_STREAM_STUB_TIMEOUT_USEC); | |
e4bed40f ZJS |
1076 | if (r < 0) { |
1077 | safe_close(cfd); | |
1078 | return r; | |
1079 | } | |
1080 | ||
1081 | stream->stub_listener_extra = l; | |
e4bed40f ZJS |
1082 | |
1083 | /* We let the reference to the stream dangle here, it will be dropped later by the complete callback. */ | |
1084 | ||
1085 | return 0; | |
1086 | } | |
1087 | ||
1088 | static int on_dns_stub_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
1089 | return on_dns_stub_stream_internal(s, fd, revents, userdata, NULL); | |
1090 | } | |
1091 | ||
1092 | static int on_dns_stub_stream_extra(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
99534007 | 1093 | DnsStubListenerExtra *l = ASSERT_PTR(userdata); |
e4bed40f | 1094 | |
e4bed40f ZJS |
1095 | return on_dns_stub_stream_internal(s, fd, revents, l->manager, l); |
1096 | } | |
1097 | ||
af8b1384 | 1098 | static int set_dns_stub_common_socket_options(int fd, int family) { |
1f05101f SS |
1099 | int r; |
1100 | ||
1101 | assert(fd >= 0); | |
af8b1384 | 1102 | assert(IN_SET(family, AF_INET, AF_INET6)); |
1f05101f SS |
1103 | |
1104 | r = setsockopt_int(fd, SOL_SOCKET, SO_REUSEADDR, true); | |
1105 | if (r < 0) | |
1106 | return r; | |
1107 | ||
5d0fe423 LP |
1108 | r = socket_set_recvpktinfo(fd, family, true); |
1109 | if (r < 0) | |
1110 | return r; | |
af8b1384 | 1111 | |
5d0fe423 LP |
1112 | r = socket_set_recvttl(fd, family, true); |
1113 | if (r < 0) | |
1114 | return r; | |
af8b1384 YW |
1115 | |
1116 | return 0; | |
1f05101f SS |
1117 | } |
1118 | ||
8624f128 LP |
1119 | static int set_dns_stub_common_tcp_socket_options(int fd) { |
1120 | int r; | |
1121 | ||
1122 | assert(fd >= 0); | |
1123 | ||
1124 | r = setsockopt_int(fd, IPPROTO_TCP, TCP_FASTOPEN, 5); /* Everybody appears to pick qlen=5, let's do the same here. */ | |
1125 | if (r < 0) | |
1126 | log_debug_errno(r, "Failed to enable TCP_FASTOPEN on TCP listening socket, ignoring: %m"); | |
1127 | ||
1128 | r = setsockopt_int(fd, IPPROTO_TCP, TCP_NODELAY, true); | |
1129 | if (r < 0) | |
1130 | log_debug_errno(r, "Failed to enable TCP_NODELAY mode, ignoring: %m"); | |
1131 | ||
1132 | return 0; | |
1133 | } | |
1134 | ||
a8d09063 LP |
1135 | static int manager_dns_stub_fd( |
1136 | Manager *m, | |
1137 | int family, | |
1138 | const union in_addr_union *listen_addr, | |
1139 | int type) { | |
1140 | ||
1141 | sd_event_source **event_source; | |
254d1313 | 1142 | _cleanup_close_ int fd = -EBADF; |
a8d09063 | 1143 | union sockaddr_union sa; |
b30bf55d LP |
1144 | int r; |
1145 | ||
e1158539 LP |
1146 | assert(m); |
1147 | assert(listen_addr); | |
1148 | ||
a8d09063 LP |
1149 | if (type == SOCK_DGRAM) |
1150 | event_source = address_is_proxy(family, listen_addr) ? &m->dns_proxy_stub_udp_event_source : &m->dns_stub_udp_event_source; | |
1151 | else if (type == SOCK_STREAM) | |
1152 | event_source = address_is_proxy(family, listen_addr) ? &m->dns_proxy_stub_tcp_event_source : &m->dns_stub_tcp_event_source; | |
1153 | else | |
1154 | return -EPROTONOSUPPORT; | |
d491917c | 1155 | |
d491917c ZJS |
1156 | if (*event_source) |
1157 | return sd_event_source_get_io_fd(*event_source); | |
b30bf55d | 1158 | |
a8d09063 | 1159 | fd = socket(family, type | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); |
424e490b | 1160 | if (fd < 0) |
b30bf55d LP |
1161 | return -errno; |
1162 | ||
a8d09063 | 1163 | r = set_dns_stub_common_socket_options(fd, family); |
2ff48e98 LP |
1164 | if (r < 0) |
1165 | return r; | |
b30bf55d | 1166 | |
8624f128 LP |
1167 | if (type == SOCK_STREAM) { |
1168 | r = set_dns_stub_common_tcp_socket_options(fd); | |
1169 | if (r < 0) | |
1170 | return r; | |
1171 | } | |
1172 | ||
a8d09063 LP |
1173 | /* Set slightly different socket options for the non-proxy and the proxy binding. The former we want |
1174 | * to be accessible only from the local host, for the latter it's OK if people use NAT redirects or | |
1175 | * so to redirect external traffic to it. */ | |
1176 | ||
1177 | if (!address_is_proxy(family, listen_addr)) { | |
1178 | /* Make sure no traffic from outside the local host can leak to onto this socket */ | |
1179 | r = socket_bind_to_ifindex(fd, LOOPBACK_IFINDEX); | |
1180 | if (r < 0) | |
1181 | return r; | |
1182 | ||
1183 | r = socket_set_ttl(fd, family, 1); | |
1184 | if (r < 0) | |
1185 | return r; | |
1186 | } else if (type == SOCK_DGRAM) { | |
e1158539 LP |
1187 | /* Turn off Path MTU Discovery for UDP, for security reasons. See socket_disable_pmtud() for |
1188 | * a longer discussion. (We only do this for sockets that are potentially externally | |
1189 | * accessible, i.e. the proxy stub one. For the non-proxy one we instead set the TTL to 1, | |
1190 | * see above, so that packets don't get routed at all.) */ | |
a8d09063 LP |
1191 | r = socket_disable_pmtud(fd, family); |
1192 | if (r < 0) | |
1193 | log_debug_errno(r, "Failed to disable UDP PMTUD, ignoring: %m"); | |
1194 | ||
1195 | r = socket_set_recvfragsize(fd, family, true); | |
1196 | if (r < 0) | |
1197 | log_debug_errno(r, "Failed to enable fragment size reception, ignoring: %m"); | |
1198 | } | |
b30bf55d | 1199 | |
a8d09063 | 1200 | r = sockaddr_set_in_addr(&sa, family, listen_addr, 53); |
d491917c ZJS |
1201 | if (r < 0) |
1202 | return r; | |
1203 | ||
424e490b ZJS |
1204 | if (bind(fd, &sa.sa, sizeof(sa.in)) < 0) |
1205 | return -errno; | |
b30bf55d | 1206 | |
d491917c | 1207 | if (type == SOCK_STREAM && |
768fcd77 | 1208 | listen(fd, SOMAXCONN_DELUXE) < 0) |
d491917c ZJS |
1209 | return -errno; |
1210 | ||
1211 | r = sd_event_add_io(m->event, event_source, fd, EPOLLIN, | |
1212 | type == SOCK_DGRAM ? on_dns_stub_packet : on_dns_stub_stream, | |
1213 | m); | |
b30bf55d | 1214 | if (r < 0) |
424e490b | 1215 | return r; |
b30bf55d | 1216 | |
d491917c | 1217 | r = sd_event_source_set_io_fd_own(*event_source, true); |
7216a3b5 YW |
1218 | if (r < 0) |
1219 | return r; | |
1220 | ||
d491917c ZJS |
1221 | (void) sd_event_source_set_description(*event_source, |
1222 | type == SOCK_DGRAM ? "dns-stub-udp" : "dns-stub-tcp"); | |
b30bf55d | 1223 | |
7216a3b5 | 1224 | return TAKE_FD(fd); |
b30bf55d LP |
1225 | } |
1226 | ||
b5febb3f | 1227 | static int manager_dns_stub_fd_extra(Manager *m, DnsStubListenerExtra *l, int type) { |
1f05101f | 1228 | _cleanup_free_ char *pretty = NULL; |
254d1313 | 1229 | _cleanup_close_ int fd = -EBADF; |
ca8b62b5 | 1230 | union sockaddr_union sa; |
1f05101f SS |
1231 | int r; |
1232 | ||
0354029b | 1233 | assert(m); |
a8d09063 | 1234 | assert(l); |
b5febb3f | 1235 | assert(IN_SET(type, SOCK_DGRAM, SOCK_STREAM)); |
0354029b | 1236 | |
b5febb3f ZJS |
1237 | sd_event_source **event_source = type == SOCK_DGRAM ? &l->udp_event_source : &l->tcp_event_source; |
1238 | if (*event_source) | |
1239 | return sd_event_source_get_io_fd(*event_source); | |
1f05101f | 1240 | |
0398c084 DDM |
1241 | if (!have_effective_cap(CAP_NET_BIND_SERVICE) && dns_stub_listener_extra_port(l) < 1024) { |
1242 | log_warning("Missing CAP_NET_BIND_SERVICE capability, not creating extra stub listener on port %hu.", | |
1243 | dns_stub_listener_extra_port(l)); | |
1244 | return 0; | |
1245 | } | |
1246 | ||
ca8b62b5 YW |
1247 | if (l->family == AF_INET) |
1248 | sa = (union sockaddr_union) { | |
1249 | .in.sin_family = l->family, | |
49ef064c | 1250 | .in.sin_port = htobe16(dns_stub_listener_extra_port(l)), |
ca8b62b5 YW |
1251 | .in.sin_addr = l->address.in, |
1252 | }; | |
1253 | else | |
1254 | sa = (union sockaddr_union) { | |
1255 | .in6.sin6_family = l->family, | |
49ef064c | 1256 | .in6.sin6_port = htobe16(dns_stub_listener_extra_port(l)), |
ca8b62b5 YW |
1257 | .in6.sin6_addr = l->address.in6, |
1258 | }; | |
1259 | ||
b5febb3f | 1260 | fd = socket(l->family, type | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); |
1f05101f SS |
1261 | if (fd < 0) { |
1262 | r = -errno; | |
1263 | goto fail; | |
1264 | } | |
1265 | ||
af8b1384 | 1266 | r = set_dns_stub_common_socket_options(fd, l->family); |
1f05101f SS |
1267 | if (r < 0) |
1268 | goto fail; | |
1269 | ||
8624f128 LP |
1270 | if (type == SOCK_STREAM) { |
1271 | r = set_dns_stub_common_tcp_socket_options(fd); | |
1272 | if (r < 0) | |
1273 | goto fail; | |
1274 | } | |
1275 | ||
69e3234d | 1276 | /* Do not set IP_TTL for extra DNS stub listeners, as the address may not be local and in that case |
b5febb3f ZJS |
1277 | * people may want ttl > 1. */ |
1278 | ||
5d0fe423 | 1279 | r = socket_set_freebind(fd, l->family, true); |
b5febb3f ZJS |
1280 | if (r < 0) |
1281 | goto fail; | |
1282 | ||
eb170e75 LP |
1283 | if (type == SOCK_DGRAM) { |
1284 | r = socket_disable_pmtud(fd, l->family); | |
1285 | if (r < 0) | |
1286 | log_debug_errno(r, "Failed to disable UDP PMTUD, ignoring: %m"); | |
20a001bd LP |
1287 | |
1288 | r = socket_set_recvfragsize(fd, l->family, true); | |
1289 | if (r < 0) | |
1290 | log_debug_errno(r, "Failed to enable fragment size reception, ignoring: %m"); | |
eb170e75 LP |
1291 | } |
1292 | ||
ded15213 LP |
1293 | r = RET_NERRNO(bind(fd, &sa.sa, SOCKADDR_LEN(sa))); |
1294 | if (r < 0) | |
1f05101f | 1295 | goto fail; |
1f05101f | 1296 | |
b5febb3f | 1297 | if (type == SOCK_STREAM && |
768fcd77 | 1298 | listen(fd, SOMAXCONN_DELUXE) < 0) { |
b5febb3f ZJS |
1299 | r = -errno; |
1300 | goto fail; | |
1301 | } | |
1302 | ||
1303 | r = sd_event_add_io(m->event, event_source, fd, EPOLLIN, | |
1304 | type == SOCK_DGRAM ? on_dns_stub_packet_extra : on_dns_stub_stream_extra, | |
1305 | l); | |
1f05101f SS |
1306 | if (r < 0) |
1307 | goto fail; | |
1308 | ||
b5febb3f | 1309 | r = sd_event_source_set_io_fd_own(*event_source, true); |
7216a3b5 YW |
1310 | if (r < 0) |
1311 | goto fail; | |
1312 | ||
b5febb3f ZJS |
1313 | (void) sd_event_source_set_description(*event_source, |
1314 | type == SOCK_DGRAM ? "dns-stub-udp-extra" : "dns-stub-tcp-extra"); | |
1f05101f SS |
1315 | |
1316 | if (DEBUG_LOGGING) { | |
ca8b62b5 | 1317 | (void) in_addr_port_to_string(l->family, &l->address, l->port, &pretty); |
b5febb3f ZJS |
1318 | log_debug("Listening on %s socket %s.", |
1319 | type == SOCK_DGRAM ? "UDP" : "TCP", | |
1320 | strnull(pretty)); | |
1f05101f SS |
1321 | } |
1322 | ||
7216a3b5 | 1323 | return TAKE_FD(fd); |
1f05101f | 1324 | |
b4b7ea1b | 1325 | fail: |
1c17bcb3 | 1326 | assert(r < 0); |
ca8b62b5 | 1327 | (void) in_addr_port_to_string(l->family, &l->address, l->port, &pretty); |
b5febb3f ZJS |
1328 | return log_warning_errno(r, |
1329 | r == -EADDRINUSE ? "Another process is already listening on %s socket %s: %m" : | |
1330 | "Failed to listen on %s socket %s: %m", | |
1331 | type == SOCK_DGRAM ? "UDP" : "TCP", | |
1332 | strnull(pretty)); | |
1f05101f SS |
1333 | } |
1334 | ||
b30bf55d | 1335 | int manager_dns_stub_start(Manager *m) { |
a8d09063 | 1336 | int r; |
b30bf55d LP |
1337 | |
1338 | assert(m); | |
1339 | ||
d5da7707 ZJS |
1340 | if (m->dns_stub_listener_mode == DNS_STUB_LISTENER_NO) |
1341 | log_debug("Not creating stub listener."); | |
0398c084 DDM |
1342 | else if (!have_effective_cap(CAP_NET_BIND_SERVICE)) |
1343 | log_warning("Missing CAP_NET_BIND_SERVICE capability, not creating stub listener on port 53."); | |
a8d09063 LP |
1344 | else { |
1345 | static const struct { | |
1346 | uint32_t addr; | |
1347 | int socket_type; | |
1348 | } stub_sockets[] = { | |
1349 | { INADDR_DNS_STUB, SOCK_DGRAM }, | |
1350 | { INADDR_DNS_STUB, SOCK_STREAM }, | |
1351 | { INADDR_DNS_PROXY_STUB, SOCK_DGRAM }, | |
1352 | { INADDR_DNS_PROXY_STUB, SOCK_STREAM }, | |
1353 | }; | |
1354 | ||
d5da7707 ZJS |
1355 | log_debug("Creating stub listener using %s.", |
1356 | m->dns_stub_listener_mode == DNS_STUB_LISTENER_UDP ? "UDP" : | |
1357 | m->dns_stub_listener_mode == DNS_STUB_LISTENER_TCP ? "TCP" : | |
1358 | "UDP/TCP"); | |
1359 | ||
a8d09063 LP |
1360 | for (size_t i = 0; i < ELEMENTSOF(stub_sockets); i++) { |
1361 | union in_addr_union a = { | |
1362 | .in.s_addr = htobe32(stub_sockets[i].addr), | |
1363 | }; | |
b30bf55d | 1364 | |
a8d09063 LP |
1365 | if (m->dns_stub_listener_mode == DNS_STUB_LISTENER_UDP && stub_sockets[i].socket_type == SOCK_STREAM) |
1366 | continue; | |
1367 | if (m->dns_stub_listener_mode == DNS_STUB_LISTENER_TCP && stub_sockets[i].socket_type == SOCK_DGRAM) | |
1368 | continue; | |
1369 | ||
1370 | r = manager_dns_stub_fd(m, AF_INET, &a, stub_sockets[i].socket_type); | |
1371 | if (r < 0) { | |
1372 | _cleanup_free_ char *busy_socket = NULL; | |
1373 | ||
1374 | if (asprintf(&busy_socket, | |
1375 | "%s socket " IPV4_ADDRESS_FMT_STR ":53", | |
1376 | stub_sockets[i].socket_type == SOCK_DGRAM ? "UDP" : "TCP", | |
1377 | IPV4_ADDRESS_FMT_VAL(a.in)) < 0) | |
1378 | return log_oom(); | |
1379 | ||
1380 | if (IN_SET(r, -EADDRINUSE, -EPERM)) { | |
1381 | log_warning_errno(r, | |
1382 | r == -EADDRINUSE ? "Another process is already listening on %s.\n" | |
1383 | "Turning off local DNS stub support." : | |
1384 | "Failed to listen on %s: %m.\n" | |
1385 | "Turning off local DNS stub support.", | |
1386 | busy_socket); | |
1387 | manager_dns_stub_stop(m); | |
1388 | break; | |
1389 | } | |
b30bf55d | 1390 | |
a8d09063 LP |
1391 | return log_error_errno(r, "Failed to listen on %s: %m", busy_socket); |
1392 | } | |
1393 | } | |
1394 | } | |
b30bf55d | 1395 | |
1f05101f | 1396 | if (!ordered_set_isempty(m->dns_extra_stub_listeners)) { |
36aaabc3 | 1397 | DnsStubListenerExtra *l; |
1f05101f | 1398 | |
dce65cd4 | 1399 | log_debug("Creating extra stub listeners."); |
1f05101f | 1400 | |
90e74a66 | 1401 | ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners) { |
7314b397 | 1402 | if (FLAGS_SET(l->mode, DNS_STUB_LISTENER_UDP)) |
b5febb3f | 1403 | (void) manager_dns_stub_fd_extra(m, l, SOCK_DGRAM); |
7314b397 | 1404 | if (FLAGS_SET(l->mode, DNS_STUB_LISTENER_TCP)) |
b5febb3f | 1405 | (void) manager_dns_stub_fd_extra(m, l, SOCK_STREAM); |
7314b397 | 1406 | } |
1f05101f SS |
1407 | } |
1408 | ||
b30bf55d LP |
1409 | return 0; |
1410 | } | |
1411 | ||
1412 | void manager_dns_stub_stop(Manager *m) { | |
1413 | assert(m); | |
1414 | ||
97935302 ZJS |
1415 | m->dns_stub_udp_event_source = sd_event_source_disable_unref(m->dns_stub_udp_event_source); |
1416 | m->dns_stub_tcp_event_source = sd_event_source_disable_unref(m->dns_stub_tcp_event_source); | |
a8d09063 LP |
1417 | m->dns_proxy_stub_udp_event_source = sd_event_source_disable_unref(m->dns_proxy_stub_udp_event_source); |
1418 | m->dns_proxy_stub_tcp_event_source = sd_event_source_disable_unref(m->dns_proxy_stub_tcp_event_source); | |
b30bf55d | 1419 | } |
ae8f0ec3 LP |
1420 | |
1421 | static const char* const dns_stub_listener_mode_table[_DNS_STUB_LISTENER_MODE_MAX] = { | |
97935302 | 1422 | [DNS_STUB_LISTENER_NO] = "no", |
ae8f0ec3 LP |
1423 | [DNS_STUB_LISTENER_UDP] = "udp", |
1424 | [DNS_STUB_LISTENER_TCP] = "tcp", | |
1425 | [DNS_STUB_LISTENER_YES] = "yes", | |
1426 | }; | |
1427 | DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(dns_stub_listener_mode, DnsStubListenerMode, DNS_STUB_LISTENER_YES); |