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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
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 LP |
11 | #include "socket-util.h" |
12 | ||
13 | /* The MTU of the loopback device is 64K on Linux, advertise that as maximum datagram size, but subtract the Ethernet, | |
14 | * IP and UDP header sizes */ | |
15 | #define ADVERTISE_DATAGRAM_SIZE_MAX (65536U-14U-20U-8U) | |
16 | ||
424e490b ZJS |
17 | static int manager_dns_stub_udp_fd(Manager *m); |
18 | static int manager_dns_stub_tcp_fd(Manager *m); | |
19 | ||
bf22f231 | 20 | int dns_stub_listener_extra_new(DNSStubListenerExtra **ret) { |
1f05101f SS |
21 | DNSStubListenerExtra *l; |
22 | ||
7216a3b5 | 23 | l = new0(DNSStubListenerExtra, 1); |
1f05101f SS |
24 | if (!l) |
25 | return -ENOMEM; | |
26 | ||
1f05101f SS |
27 | *ret = TAKE_PTR(l); |
28 | ||
29 | return 0; | |
30 | } | |
31 | ||
bf22f231 YW |
32 | DNSStubListenerExtra *dns_stub_listener_extra_free(DNSStubListenerExtra *p) { |
33 | if (!p) | |
34 | return NULL; | |
35 | ||
36 | p->udp_event_source = sd_event_source_unref(p->udp_event_source); | |
37 | p->tcp_event_source = sd_event_source_unref(p->tcp_event_source); | |
bf22f231 YW |
38 | |
39 | return mfree(p); | |
40 | } | |
41 | ||
b30bf55d | 42 | static int dns_stub_make_reply_packet( |
e8d23f92 | 43 | DnsPacket **p, |
51027656 | 44 | size_t max_size, |
b30bf55d | 45 | DnsQuestion *q, |
51027656 LP |
46 | DnsAnswer *answer, |
47 | bool *ret_truncated) { | |
b30bf55d | 48 | |
51027656 | 49 | bool truncated = false; |
b30bf55d LP |
50 | DnsResourceRecord *rr; |
51 | unsigned c = 0; | |
52 | int r; | |
53 | ||
e8d23f92 LP |
54 | assert(p); |
55 | ||
b30bf55d LP |
56 | /* Note that we don't bother with any additional RRs, as this is stub is for local lookups only, and hence |
57 | * roundtrips aren't expensive. */ | |
58 | ||
e8d23f92 | 59 | if (!*p) { |
51027656 | 60 | r = dns_packet_new(p, DNS_PROTOCOL_DNS, 0, max_size); |
e8d23f92 LP |
61 | if (r < 0) |
62 | return r; | |
b30bf55d | 63 | |
e8d23f92 LP |
64 | r = dns_packet_append_question(*p, q); |
65 | if (r < 0) | |
66 | return r; | |
b30bf55d | 67 | |
e8d23f92 LP |
68 | DNS_PACKET_HEADER(*p)->qdcount = htobe16(dns_question_size(q)); |
69 | } | |
b30bf55d LP |
70 | |
71 | DNS_ANSWER_FOREACH(rr, answer) { | |
e8d23f92 | 72 | |
b30bf55d LP |
73 | r = dns_question_matches_rr(q, rr, NULL); |
74 | if (r < 0) | |
75 | return r; | |
76 | if (r > 0) | |
77 | goto add; | |
78 | ||
79 | r = dns_question_matches_cname_or_dname(q, rr, NULL); | |
80 | if (r < 0) | |
81 | return r; | |
82 | if (r > 0) | |
83 | goto add; | |
84 | ||
85 | continue; | |
86 | add: | |
01c901e2 | 87 | r = dns_packet_append_rr(*p, rr, 0, NULL, NULL); |
51027656 LP |
88 | if (r == -EMSGSIZE) { |
89 | truncated = true; | |
90 | break; | |
91 | } | |
b30bf55d LP |
92 | if (r < 0) |
93 | return r; | |
94 | ||
95 | c++; | |
96 | } | |
e8d23f92 | 97 | |
51027656 LP |
98 | if (ret_truncated) |
99 | *ret_truncated = truncated; | |
100 | else if (truncated) | |
101 | return -EMSGSIZE; | |
102 | ||
e8d23f92 LP |
103 | DNS_PACKET_HEADER(*p)->ancount = htobe16(be16toh(DNS_PACKET_HEADER(*p)->ancount) + c); |
104 | ||
105 | return 0; | |
106 | } | |
107 | ||
108 | static int dns_stub_finish_reply_packet( | |
109 | DnsPacket *p, | |
110 | uint16_t id, | |
111 | int rcode, | |
51027656 | 112 | bool tc, /* set the Truncated bit? */ |
e8d23f92 LP |
113 | bool add_opt, /* add an OPT RR to this packet? */ |
114 | bool edns0_do, /* set the EDNS0 DNSSEC OK bit? */ | |
115 | bool ad) { /* set the DNSSEC authenticated data bit? */ | |
116 | ||
117 | int r; | |
118 | ||
119 | assert(p); | |
120 | ||
ff4caaae LP |
121 | if (add_opt) { |
122 | r = dns_packet_append_opt(p, ADVERTISE_DATAGRAM_SIZE_MAX, edns0_do, rcode, NULL); | |
123 | if (r == -EMSGSIZE) /* Hit the size limit? then indicate truncation */ | |
124 | tc = true; | |
125 | else if (r < 0) | |
126 | return r; | |
127 | ||
128 | } else { | |
941dd294 LP |
129 | /* If the client can't to EDNS0, don't do DO either */ |
130 | edns0_do = false; | |
131 | ||
132 | /* If the client didn't do EDNS, clamp the rcode to 4 bit */ | |
133 | if (rcode > 0xF) | |
134 | rcode = DNS_RCODE_SERVFAIL; | |
135 | } | |
136 | ||
137 | /* Don't set the AD bit unless DO is on, too */ | |
138 | if (!edns0_do) | |
139 | ad = false; | |
e8d23f92 LP |
140 | |
141 | DNS_PACKET_HEADER(p)->id = id; | |
142 | ||
143 | DNS_PACKET_HEADER(p)->flags = htobe16(DNS_PACKET_MAKE_FLAGS( | |
51027656 LP |
144 | 1 /* qr */, |
145 | 0 /* opcode */, | |
146 | 0 /* aa */, | |
147 | tc /* tc */, | |
148 | 1 /* rd */, | |
149 | 1 /* ra */, | |
e8d23f92 | 150 | ad /* ad */, |
51027656 | 151 | 0 /* cd */, |
e8d23f92 | 152 | rcode)); |
b30bf55d | 153 | |
b30bf55d LP |
154 | return 0; |
155 | } | |
156 | ||
b30bf55d LP |
157 | static int dns_stub_send(Manager *m, DnsStream *s, DnsPacket *p, DnsPacket *reply) { |
158 | int r; | |
159 | ||
160 | assert(m); | |
161 | assert(p); | |
162 | assert(reply); | |
163 | ||
164 | if (s) | |
165 | r = dns_stream_write_packet(s, reply); | |
166 | else { | |
167 | int fd; | |
168 | ||
b30bf55d LP |
169 | fd = manager_dns_stub_udp_fd(m); |
170 | if (fd < 0) | |
171 | return log_debug_errno(fd, "Failed to get reply socket: %m"); | |
172 | ||
173 | /* Note that it is essential here that we explicitly choose the source IP address for this packet. This | |
174 | * is because otherwise the kernel will choose it automatically based on the routing table and will | |
175 | * thus pick 127.0.0.1 rather than 127.0.0.53. */ | |
176 | ||
177 | r = manager_send(m, fd, LOOPBACK_IFINDEX, p->family, &p->sender, p->sender_port, &p->destination, reply); | |
178 | } | |
179 | if (r < 0) | |
180 | return log_debug_errno(r, "Failed to send reply packet: %m"); | |
181 | ||
182 | return 0; | |
183 | } | |
184 | ||
2b2d98c1 | 185 | static int dns_stub_send_failure(Manager *m, DnsStream *s, DnsPacket *p, int rcode, bool authenticated) { |
b30bf55d LP |
186 | _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL; |
187 | int r; | |
188 | ||
189 | assert(m); | |
190 | assert(p); | |
191 | ||
51027656 | 192 | r = dns_stub_make_reply_packet(&reply, DNS_PACKET_PAYLOAD_SIZE_MAX(p), p->question, NULL, NULL); |
e8d23f92 LP |
193 | if (r < 0) |
194 | return log_debug_errno(r, "Failed to make failure packet: %m"); | |
195 | ||
51027656 | 196 | r = dns_stub_finish_reply_packet(reply, DNS_PACKET_ID(p), rcode, false, !!p->opt, DNS_PACKET_DO(p), authenticated); |
b30bf55d LP |
197 | if (r < 0) |
198 | return log_debug_errno(r, "Failed to build failure packet: %m"); | |
199 | ||
200 | return dns_stub_send(m, s, p, reply); | |
201 | } | |
202 | ||
203 | static void dns_stub_query_complete(DnsQuery *q) { | |
204 | int r; | |
205 | ||
206 | assert(q); | |
207 | assert(q->request_dns_packet); | |
208 | ||
209 | switch (q->state) { | |
210 | ||
51027656 LP |
211 | case DNS_TRANSACTION_SUCCESS: { |
212 | bool truncated; | |
e8d23f92 | 213 | |
51027656 | 214 | r = dns_stub_make_reply_packet(&q->reply_dns_packet, DNS_PACKET_PAYLOAD_SIZE_MAX(q->request_dns_packet), q->question_idna, q->answer, &truncated); |
e8d23f92 LP |
215 | if (r < 0) { |
216 | log_debug_errno(r, "Failed to build reply packet: %m"); | |
217 | break; | |
218 | } | |
b30bf55d | 219 | |
aa11cab9 LP |
220 | if (!truncated) { |
221 | r = dns_query_process_cname(q); | |
222 | if (r == -ELOOP) { | |
223 | (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_SERVFAIL, false); | |
224 | break; | |
225 | } | |
226 | if (r < 0) { | |
227 | log_debug_errno(r, "Failed to process CNAME: %m"); | |
228 | break; | |
229 | } | |
230 | if (r == DNS_QUERY_RESTARTED) | |
231 | return; | |
e8d23f92 | 232 | } |
e8d23f92 LP |
233 | |
234 | r = dns_stub_finish_reply_packet( | |
235 | q->reply_dns_packet, | |
b30bf55d LP |
236 | DNS_PACKET_ID(q->request_dns_packet), |
237 | q->answer_rcode, | |
51027656 | 238 | truncated, |
b30bf55d LP |
239 | !!q->request_dns_packet->opt, |
240 | DNS_PACKET_DO(q->request_dns_packet), | |
941dd294 | 241 | dns_query_fully_authenticated(q)); |
b30bf55d | 242 | if (r < 0) { |
e8d23f92 | 243 | log_debug_errno(r, "Failed to finish reply packet: %m"); |
b30bf55d LP |
244 | break; |
245 | } | |
246 | ||
e8d23f92 | 247 | (void) dns_stub_send(q->manager, q->request_dns_stream, q->request_dns_packet, q->reply_dns_packet); |
b30bf55d | 248 | break; |
51027656 | 249 | } |
b30bf55d LP |
250 | |
251 | case DNS_TRANSACTION_RCODE_FAILURE: | |
2b2d98c1 | 252 | (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, q->answer_rcode, dns_query_fully_authenticated(q)); |
b30bf55d LP |
253 | break; |
254 | ||
255 | case DNS_TRANSACTION_NOT_FOUND: | |
2b2d98c1 | 256 | (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_NXDOMAIN, dns_query_fully_authenticated(q)); |
b30bf55d LP |
257 | break; |
258 | ||
259 | case DNS_TRANSACTION_TIMEOUT: | |
260 | case DNS_TRANSACTION_ATTEMPTS_MAX_REACHED: | |
261 | /* Propagate a timeout as a no packet, i.e. that the client also gets a timeout */ | |
262 | break; | |
263 | ||
264 | case DNS_TRANSACTION_NO_SERVERS: | |
265 | case DNS_TRANSACTION_INVALID_REPLY: | |
266 | case DNS_TRANSACTION_ERRNO: | |
267 | case DNS_TRANSACTION_ABORTED: | |
268 | case DNS_TRANSACTION_DNSSEC_FAILED: | |
269 | case DNS_TRANSACTION_NO_TRUST_ANCHOR: | |
270 | case DNS_TRANSACTION_RR_TYPE_UNSUPPORTED: | |
271 | case DNS_TRANSACTION_NETWORK_DOWN: | |
2b2d98c1 | 272 | (void) dns_stub_send_failure(q->manager, q->request_dns_stream, q->request_dns_packet, DNS_RCODE_SERVFAIL, false); |
b30bf55d LP |
273 | break; |
274 | ||
275 | case DNS_TRANSACTION_NULL: | |
276 | case DNS_TRANSACTION_PENDING: | |
277 | case DNS_TRANSACTION_VALIDATING: | |
278 | default: | |
279 | assert_not_reached("Impossible state"); | |
280 | } | |
281 | ||
b30bf55d LP |
282 | dns_query_free(q); |
283 | } | |
284 | ||
285 | static int dns_stub_stream_complete(DnsStream *s, int error) { | |
286 | assert(s); | |
287 | ||
b412af57 LP |
288 | log_debug_errno(error, "DNS TCP connection terminated, destroying queries: %m"); |
289 | ||
290 | for (;;) { | |
291 | DnsQuery *q; | |
292 | ||
293 | q = set_first(s->queries); | |
294 | if (!q) | |
295 | break; | |
b30bf55d | 296 | |
b412af57 LP |
297 | dns_query_free(q); |
298 | } | |
b30bf55d | 299 | |
b412af57 LP |
300 | /* This drops the implicit ref we keep around since it was allocated, as incoming stub connections |
301 | * should be kept as long as the client wants to. */ | |
302 | dns_stream_unref(s); | |
b30bf55d LP |
303 | return 0; |
304 | } | |
305 | ||
306 | static void dns_stub_process_query(Manager *m, DnsStream *s, DnsPacket *p) { | |
ceb17827 | 307 | _cleanup_(dns_query_freep) DnsQuery *q = NULL; |
b30bf55d LP |
308 | int r; |
309 | ||
310 | assert(m); | |
311 | assert(p); | |
312 | assert(p->protocol == DNS_PROTOCOL_DNS); | |
313 | ||
b30bf55d LP |
314 | if (in_addr_is_localhost(p->family, &p->sender) <= 0 || |
315 | in_addr_is_localhost(p->family, &p->destination) <= 0) { | |
316 | log_error("Got packet on unexpected IP range, refusing."); | |
2b2d98c1 | 317 | dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false); |
ceb17827 | 318 | return; |
b30bf55d LP |
319 | } |
320 | ||
321 | r = dns_packet_extract(p); | |
322 | if (r < 0) { | |
323 | log_debug_errno(r, "Failed to extract resources from incoming packet, ignoring packet: %m"); | |
2b2d98c1 | 324 | dns_stub_send_failure(m, s, p, DNS_RCODE_FORMERR, false); |
ceb17827 | 325 | return; |
b30bf55d LP |
326 | } |
327 | ||
328 | if (!DNS_PACKET_VERSION_SUPPORTED(p)) { | |
329 | log_debug("Got EDNS OPT field with unsupported version number."); | |
2b2d98c1 | 330 | dns_stub_send_failure(m, s, p, DNS_RCODE_BADVERS, false); |
ceb17827 | 331 | return; |
b30bf55d LP |
332 | } |
333 | ||
334 | if (dns_type_is_obsolete(p->question->keys[0]->type)) { | |
335 | log_debug("Got message with obsolete key type, refusing."); | |
2b2d98c1 | 336 | dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false); |
ceb17827 | 337 | return; |
b30bf55d LP |
338 | } |
339 | ||
340 | if (dns_type_is_zone_transer(p->question->keys[0]->type)) { | |
341 | log_debug("Got request for zone transfer, refusing."); | |
2b2d98c1 | 342 | dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false); |
ceb17827 | 343 | return; |
b30bf55d LP |
344 | } |
345 | ||
346 | if (!DNS_PACKET_RD(p)) { | |
347 | /* If the "rd" bit is off (i.e. recursion was not requested), then refuse operation */ | |
348 | log_debug("Got request with recursion disabled, refusing."); | |
2b2d98c1 | 349 | dns_stub_send_failure(m, s, p, DNS_RCODE_REFUSED, false); |
ceb17827 | 350 | return; |
b30bf55d LP |
351 | } |
352 | ||
353 | if (DNS_PACKET_DO(p) && DNS_PACKET_CD(p)) { | |
354 | log_debug("Got request with DNSSEC CD bit set, refusing."); | |
2b2d98c1 | 355 | dns_stub_send_failure(m, s, p, DNS_RCODE_NOTIMP, false); |
ceb17827 | 356 | return; |
b30bf55d LP |
357 | } |
358 | ||
e8d23f92 | 359 | r = dns_query_new(m, &q, p->question, p->question, 0, SD_RESOLVED_PROTOCOLS_ALL|SD_RESOLVED_NO_SEARCH); |
b30bf55d LP |
360 | if (r < 0) { |
361 | log_error_errno(r, "Failed to generate query object: %m"); | |
2b2d98c1 | 362 | dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false); |
ceb17827 | 363 | return; |
b30bf55d LP |
364 | } |
365 | ||
366 | /* Request that the TTL is corrected by the cached time for this lookup, so that we return vaguely useful TTLs */ | |
367 | q->clamp_ttl = true; | |
368 | ||
369 | q->request_dns_packet = dns_packet_ref(p); | |
370 | q->request_dns_stream = dns_stream_ref(s); /* make sure the stream stays around until we can send a reply through it */ | |
371 | q->complete = dns_stub_query_complete; | |
372 | ||
373 | if (s) { | |
b412af57 LP |
374 | /* Remember which queries belong to this stream, so that we can cancel them when the stream |
375 | * is disconnected early */ | |
376 | ||
ceb17827 | 377 | r = set_ensure_put(&s->queries, NULL, q); |
b412af57 LP |
378 | if (r < 0) { |
379 | log_oom(); | |
ceb17827 | 380 | return; |
b412af57 | 381 | } |
ceb17827 | 382 | assert(r > 0); |
b30bf55d LP |
383 | } |
384 | ||
385 | r = dns_query_go(q); | |
386 | if (r < 0) { | |
387 | log_error_errno(r, "Failed to start query: %m"); | |
2b2d98c1 | 388 | dns_stub_send_failure(m, s, p, DNS_RCODE_SERVFAIL, false); |
ceb17827 | 389 | return; |
b30bf55d LP |
390 | } |
391 | ||
52e63427 | 392 | log_debug("Processing query..."); |
ceb17827 | 393 | TAKE_PTR(q); |
b30bf55d LP |
394 | } |
395 | ||
396 | static int on_dns_stub_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
397 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
398 | Manager *m = userdata; | |
399 | int r; | |
400 | ||
401 | r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p); | |
402 | if (r <= 0) | |
403 | return r; | |
404 | ||
405 | if (dns_packet_validate_query(p) > 0) { | |
406 | log_debug("Got DNS stub UDP query packet for id %u", DNS_PACKET_ID(p)); | |
407 | ||
408 | dns_stub_process_query(m, NULL, p); | |
409 | } else | |
410 | log_debug("Invalid DNS stub UDP packet, ignoring."); | |
411 | ||
412 | return 0; | |
413 | } | |
414 | ||
af8b1384 | 415 | static int set_dns_stub_common_socket_options(int fd, int family) { |
1f05101f SS |
416 | int r; |
417 | ||
418 | assert(fd >= 0); | |
af8b1384 | 419 | assert(IN_SET(family, AF_INET, AF_INET6)); |
1f05101f SS |
420 | |
421 | r = setsockopt_int(fd, SOL_SOCKET, SO_REUSEADDR, true); | |
422 | if (r < 0) | |
423 | return r; | |
424 | ||
af8b1384 YW |
425 | if (family == AF_INET) { |
426 | r = setsockopt_int(fd, IPPROTO_IP, IP_PKTINFO, true); | |
427 | if (r < 0) | |
428 | return r; | |
1f05101f | 429 | |
af8b1384 YW |
430 | r = setsockopt_int(fd, IPPROTO_IP, IP_RECVTTL, true); |
431 | if (r < 0) | |
432 | return r; | |
433 | } else { | |
434 | r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, true); | |
435 | if (r < 0) | |
436 | return r; | |
437 | ||
438 | r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, true); | |
439 | if (r < 0) | |
440 | return r; | |
441 | } | |
442 | ||
443 | return 0; | |
1f05101f SS |
444 | } |
445 | ||
424e490b | 446 | static int manager_dns_stub_udp_fd(Manager *m) { |
b30bf55d LP |
447 | union sockaddr_union sa = { |
448 | .in.sin_family = AF_INET, | |
449 | .in.sin_port = htobe16(53), | |
450 | .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), | |
451 | }; | |
424e490b | 452 | _cleanup_close_ int fd = -1; |
b30bf55d LP |
453 | int r; |
454 | ||
7216a3b5 YW |
455 | if (m->dns_stub_udp_event_source) |
456 | return sd_event_source_get_io_fd(m->dns_stub_udp_event_source); | |
b30bf55d | 457 | |
424e490b ZJS |
458 | fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
459 | if (fd < 0) | |
b30bf55d LP |
460 | return -errno; |
461 | ||
af8b1384 | 462 | r = set_dns_stub_common_socket_options(fd, AF_INET); |
2ff48e98 LP |
463 | if (r < 0) |
464 | return r; | |
b30bf55d LP |
465 | |
466 | /* Make sure no traffic from outside the local host can leak to onto this socket */ | |
953a02d1 LP |
467 | r = socket_bind_to_ifindex(fd, LOOPBACK_IFINDEX); |
468 | if (r < 0) | |
469 | return r; | |
b30bf55d | 470 | |
424e490b ZJS |
471 | if (bind(fd, &sa.sa, sizeof(sa.in)) < 0) |
472 | return -errno; | |
b30bf55d | 473 | |
424e490b | 474 | r = sd_event_add_io(m->event, &m->dns_stub_udp_event_source, fd, EPOLLIN, on_dns_stub_packet, m); |
b30bf55d | 475 | if (r < 0) |
424e490b | 476 | return r; |
b30bf55d | 477 | |
7216a3b5 YW |
478 | r = sd_event_source_set_io_fd_own(m->dns_stub_udp_event_source, true); |
479 | if (r < 0) | |
480 | return r; | |
481 | ||
b30bf55d LP |
482 | (void) sd_event_source_set_description(m->dns_stub_udp_event_source, "dns-stub-udp"); |
483 | ||
7216a3b5 | 484 | return TAKE_FD(fd); |
b30bf55d LP |
485 | } |
486 | ||
1f05101f SS |
487 | static int manager_dns_stub_udp_fd_extra(Manager *m, DNSStubListenerExtra *l) { |
488 | _cleanup_free_ char *pretty = NULL; | |
489 | _cleanup_close_ int fd = -1; | |
ca8b62b5 | 490 | union sockaddr_union sa; |
1f05101f SS |
491 | int r; |
492 | ||
7216a3b5 | 493 | if (l->udp_event_source) |
1f05101f SS |
494 | return 0; |
495 | ||
ca8b62b5 YW |
496 | if (l->family == AF_INET) |
497 | sa = (union sockaddr_union) { | |
498 | .in.sin_family = l->family, | |
499 | .in.sin_port = htobe16(l->port != 0 ? l->port : 53U), | |
500 | .in.sin_addr = l->address.in, | |
501 | }; | |
502 | else | |
503 | sa = (union sockaddr_union) { | |
504 | .in6.sin6_family = l->family, | |
505 | .in6.sin6_port = htobe16(l->port != 0 ? l->port : 53U), | |
506 | .in6.sin6_addr = l->address.in6, | |
507 | }; | |
508 | ||
509 | fd = socket(l->family, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); | |
1f05101f SS |
510 | if (fd < 0) { |
511 | r = -errno; | |
512 | goto fail; | |
513 | } | |
514 | ||
af8b1384 YW |
515 | if (l->family == AF_INET) { |
516 | r = setsockopt_int(fd, IPPROTO_IP, IP_FREEBIND, true); | |
517 | if (r < 0) | |
518 | goto fail; | |
519 | } | |
1f05101f | 520 | |
af8b1384 | 521 | r = set_dns_stub_common_socket_options(fd, l->family); |
1f05101f SS |
522 | if (r < 0) |
523 | goto fail; | |
524 | ||
ca8b62b5 | 525 | if (bind(fd, &sa.sa, SOCKADDR_LEN(sa)) < 0) { |
1f05101f SS |
526 | r = -errno; |
527 | goto fail; | |
528 | } | |
529 | ||
7314b397 | 530 | r = sd_event_add_io(m->event, &l->udp_event_source, fd, EPOLLIN, on_dns_stub_packet, m); |
1f05101f SS |
531 | if (r < 0) |
532 | goto fail; | |
533 | ||
7216a3b5 YW |
534 | r = sd_event_source_set_io_fd_own(l->udp_event_source, true); |
535 | if (r < 0) | |
536 | goto fail; | |
537 | ||
7314b397 | 538 | (void) sd_event_source_set_description(l->udp_event_source, "dns-stub-udp-extra"); |
1f05101f SS |
539 | |
540 | if (DEBUG_LOGGING) { | |
ca8b62b5 | 541 | (void) in_addr_port_to_string(l->family, &l->address, l->port, &pretty); |
1f05101f SS |
542 | log_debug("Listening on UDP socket %s.", strnull(pretty)); |
543 | } | |
544 | ||
7216a3b5 | 545 | return TAKE_FD(fd); |
1f05101f | 546 | |
b4b7ea1b | 547 | fail: |
1c17bcb3 | 548 | assert(r < 0); |
ca8b62b5 | 549 | (void) in_addr_port_to_string(l->family, &l->address, l->port, &pretty); |
b4b7ea1b | 550 | if (r == -EADDRINUSE) |
1c17bcb3 YW |
551 | return log_warning_errno(r, "Another process is already listening on UDP socket %s: %m", strnull(pretty)); |
552 | return log_warning_errno(r, "Failed to listen on UDP socket %s: %m", strnull(pretty)); | |
1f05101f SS |
553 | } |
554 | ||
b30bf55d | 555 | static int on_dns_stub_stream_packet(DnsStream *s) { |
aa337a5e LP |
556 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
557 | ||
b30bf55d | 558 | assert(s); |
b30bf55d | 559 | |
aa337a5e LP |
560 | p = dns_stream_take_read_packet(s); |
561 | assert(p); | |
562 | ||
563 | if (dns_packet_validate_query(p) > 0) { | |
564 | log_debug("Got DNS stub TCP query packet for id %u", DNS_PACKET_ID(p)); | |
b30bf55d | 565 | |
aa337a5e | 566 | dns_stub_process_query(s->manager, s, p); |
b30bf55d LP |
567 | } else |
568 | log_debug("Invalid DNS stub TCP packet, ignoring."); | |
569 | ||
b30bf55d LP |
570 | return 0; |
571 | } | |
572 | ||
573 | static int on_dns_stub_stream(sd_event_source *s, int fd, uint32_t revents, void *userdata) { | |
574 | DnsStream *stream; | |
575 | Manager *m = userdata; | |
576 | int cfd, r; | |
577 | ||
578 | cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); | |
579 | if (cfd < 0) { | |
4ff9bc2e | 580 | if (ERRNO_IS_ACCEPT_AGAIN(errno)) |
b30bf55d LP |
581 | return 0; |
582 | ||
583 | return -errno; | |
584 | } | |
585 | ||
652ba568 | 586 | r = dns_stream_new(m, &stream, DNS_STREAM_STUB, DNS_PROTOCOL_DNS, cfd, NULL); |
b30bf55d LP |
587 | if (r < 0) { |
588 | safe_close(cfd); | |
589 | return r; | |
590 | } | |
591 | ||
592 | stream->on_packet = on_dns_stub_stream_packet; | |
b412af57 | 593 | stream->complete = dns_stub_stream_complete; |
b30bf55d | 594 | |
b412af57 | 595 | /* We let the reference to the stream dangle here, it will be dropped later by the complete callback. */ |
b30bf55d LP |
596 | |
597 | return 0; | |
598 | } | |
599 | ||
424e490b | 600 | static int manager_dns_stub_tcp_fd(Manager *m) { |
b30bf55d LP |
601 | union sockaddr_union sa = { |
602 | .in.sin_family = AF_INET, | |
603 | .in.sin_addr.s_addr = htobe32(INADDR_DNS_STUB), | |
604 | .in.sin_port = htobe16(53), | |
605 | }; | |
424e490b | 606 | _cleanup_close_ int fd = -1; |
b30bf55d LP |
607 | int r; |
608 | ||
7216a3b5 YW |
609 | if (m->dns_stub_tcp_event_source) |
610 | return sd_event_source_get_io_fd(m->dns_stub_tcp_event_source); | |
b30bf55d | 611 | |
424e490b ZJS |
612 | fd = socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
613 | if (fd < 0) | |
b30bf55d LP |
614 | return -errno; |
615 | ||
af8b1384 | 616 | r = set_dns_stub_common_socket_options(fd, AF_INET); |
2ff48e98 LP |
617 | if (r < 0) |
618 | return r; | |
b30bf55d | 619 | |
5b496410 | 620 | r = setsockopt_int(fd, IPPROTO_IP, IP_TTL, 1); |
2ff48e98 LP |
621 | if (r < 0) |
622 | return r; | |
b30bf55d LP |
623 | |
624 | /* Make sure no traffic from outside the local host can leak to onto this socket */ | |
953a02d1 LP |
625 | r = socket_bind_to_ifindex(fd, LOOPBACK_IFINDEX); |
626 | if (r < 0) | |
627 | return r; | |
b30bf55d | 628 | |
424e490b ZJS |
629 | if (bind(fd, &sa.sa, sizeof(sa.in)) < 0) |
630 | return -errno; | |
b30bf55d | 631 | |
424e490b ZJS |
632 | if (listen(fd, SOMAXCONN) < 0) |
633 | return -errno; | |
b30bf55d | 634 | |
424e490b | 635 | r = sd_event_add_io(m->event, &m->dns_stub_tcp_event_source, fd, EPOLLIN, on_dns_stub_stream, m); |
b30bf55d | 636 | if (r < 0) |
424e490b | 637 | return r; |
b30bf55d | 638 | |
7216a3b5 YW |
639 | r = sd_event_source_set_io_fd_own(m->dns_stub_tcp_event_source, true); |
640 | if (r < 0) | |
641 | return r; | |
642 | ||
b30bf55d LP |
643 | (void) sd_event_source_set_description(m->dns_stub_tcp_event_source, "dns-stub-tcp"); |
644 | ||
7216a3b5 | 645 | return TAKE_FD(fd); |
b30bf55d LP |
646 | } |
647 | ||
1f05101f SS |
648 | static int manager_dns_stub_tcp_fd_extra(Manager *m, DNSStubListenerExtra *l) { |
649 | _cleanup_free_ char *pretty = NULL; | |
650 | _cleanup_close_ int fd = -1; | |
ca8b62b5 | 651 | union sockaddr_union sa; |
1f05101f SS |
652 | int r; |
653 | ||
7216a3b5 YW |
654 | if (l->tcp_event_source) |
655 | return sd_event_source_get_io_fd(l->tcp_event_source);; | |
1f05101f | 656 | |
ca8b62b5 YW |
657 | if (l->family == AF_INET) |
658 | sa = (union sockaddr_union) { | |
659 | .in.sin_family = l->family, | |
660 | .in.sin_port = htobe16(l->port != 0 ? l->port : 53U), | |
661 | .in.sin_addr = l->address.in, | |
662 | }; | |
663 | else | |
664 | sa = (union sockaddr_union) { | |
665 | .in6.sin6_family = l->family, | |
666 | .in6.sin6_port = htobe16(l->port != 0 ? l->port : 53U), | |
667 | .in6.sin6_addr = l->address.in6, | |
668 | }; | |
669 | ||
670 | fd = socket(l->family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); | |
1f05101f SS |
671 | if (fd < 0) { |
672 | r = -errno; | |
673 | goto fail; | |
674 | } | |
675 | ||
af8b1384 | 676 | r = set_dns_stub_common_socket_options(fd, l->family); |
1f05101f SS |
677 | if (r < 0) |
678 | goto fail; | |
679 | ||
d40f00d7 YW |
680 | /* Do not set IP_TTL for extra DNS stub listners, as the address may not be local and in that |
681 | * case people may want ttl > 1. */ | |
1f05101f | 682 | |
af8b1384 YW |
683 | if (l->family == AF_INET) |
684 | r = setsockopt_int(fd, IPPROTO_IP, IP_FREEBIND, true); | |
685 | else | |
686 | r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_FREEBIND, true); | |
1f05101f SS |
687 | if (r < 0) |
688 | goto fail; | |
689 | ||
ca8b62b5 | 690 | if (bind(fd, &sa.sa, SOCKADDR_LEN(sa)) < 0) { |
1f05101f SS |
691 | r = -errno; |
692 | goto fail; | |
693 | } | |
694 | ||
695 | if (listen(fd, SOMAXCONN) < 0) { | |
696 | r = -errno; | |
697 | goto fail; | |
698 | } | |
699 | ||
7314b397 | 700 | r = sd_event_add_io(m->event, &l->tcp_event_source, fd, EPOLLIN, on_dns_stub_packet, m); |
1f05101f SS |
701 | if (r < 0) |
702 | goto fail; | |
703 | ||
7216a3b5 YW |
704 | r = sd_event_source_set_io_fd_own(l->tcp_event_source, true); |
705 | if (r < 0) | |
706 | goto fail; | |
707 | ||
7314b397 | 708 | (void) sd_event_source_set_description(l->tcp_event_source, "dns-stub-tcp-extra"); |
1f05101f SS |
709 | |
710 | if (DEBUG_LOGGING) { | |
ca8b62b5 | 711 | (void) in_addr_port_to_string(l->family, &l->address, l->port, &pretty); |
1f05101f SS |
712 | log_debug("Listening on TCP socket %s.", strnull(pretty)); |
713 | } | |
714 | ||
7216a3b5 | 715 | return TAKE_FD(fd); |
1f05101f | 716 | |
b4b7ea1b | 717 | fail: |
1c17bcb3 | 718 | assert(r < 0); |
ca8b62b5 | 719 | (void) in_addr_port_to_string(l->family, &l->address, l->port, &pretty); |
b4b7ea1b | 720 | if (r == -EADDRINUSE) |
1c17bcb3 YW |
721 | return log_warning_errno(r, "Another process is already listening on TCP socket %s: %m", strnull(pretty)); |
722 | return log_warning_errno(r, "Failed to listen on TCP socket %s: %m", strnull(pretty)); | |
1f05101f SS |
723 | } |
724 | ||
b30bf55d | 725 | int manager_dns_stub_start(Manager *m) { |
424e490b | 726 | const char *t = "UDP"; |
01b0669e | 727 | int r = 0; |
b30bf55d LP |
728 | |
729 | assert(m); | |
730 | ||
d5da7707 ZJS |
731 | if (m->dns_stub_listener_mode == DNS_STUB_LISTENER_NO) |
732 | log_debug("Not creating stub listener."); | |
733 | else | |
734 | log_debug("Creating stub listener using %s.", | |
735 | m->dns_stub_listener_mode == DNS_STUB_LISTENER_UDP ? "UDP" : | |
736 | m->dns_stub_listener_mode == DNS_STUB_LISTENER_TCP ? "TCP" : | |
737 | "UDP/TCP"); | |
738 | ||
88d2cb7c | 739 | if (FLAGS_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_UDP)) |
1ae43295 | 740 | r = manager_dns_stub_udp_fd(m); |
b30bf55d | 741 | |
424e490b | 742 | if (r >= 0 && |
88d2cb7c | 743 | FLAGS_SET(m->dns_stub_listener_mode, DNS_STUB_LISTENER_TCP)) { |
424e490b | 744 | t = "TCP"; |
1ae43295 | 745 | r = manager_dns_stub_tcp_fd(m); |
1ae43295 | 746 | } |
b30bf55d | 747 | |
0f4db364 ZJS |
748 | if (IN_SET(r, -EADDRINUSE, -EPERM)) { |
749 | if (r == -EADDRINUSE) | |
750 | log_warning_errno(r, | |
751 | "Another process is already listening on %s socket 127.0.0.53:53.\n" | |
752 | "Turning off local DNS stub support.", t); | |
753 | else | |
754 | log_warning_errno(r, | |
755 | "Failed to listen on %s socket 127.0.0.53:53: %m.\n" | |
756 | "Turning off local DNS stub support.", t); | |
424e490b ZJS |
757 | manager_dns_stub_stop(m); |
758 | } else if (r < 0) | |
759 | return log_error_errno(r, "Failed to listen on %s socket 127.0.0.53:53: %m", t); | |
b30bf55d | 760 | |
1f05101f SS |
761 | if (!ordered_set_isempty(m->dns_extra_stub_listeners)) { |
762 | DNSStubListenerExtra *l; | |
763 | Iterator i; | |
764 | ||
dce65cd4 | 765 | log_debug("Creating extra stub listeners."); |
1f05101f | 766 | |
7314b397 YW |
767 | ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners, i) { |
768 | if (FLAGS_SET(l->mode, DNS_STUB_LISTENER_UDP)) | |
1f05101f | 769 | (void) manager_dns_stub_udp_fd_extra(m, l); |
7314b397 | 770 | if (FLAGS_SET(l->mode, DNS_STUB_LISTENER_TCP)) |
1f05101f | 771 | (void) manager_dns_stub_tcp_fd_extra(m, l); |
7314b397 | 772 | } |
1f05101f SS |
773 | } |
774 | ||
b30bf55d LP |
775 | return 0; |
776 | } | |
777 | ||
778 | void manager_dns_stub_stop(Manager *m) { | |
779 | assert(m); | |
780 | ||
781 | m->dns_stub_udp_event_source = sd_event_source_unref(m->dns_stub_udp_event_source); | |
782 | m->dns_stub_tcp_event_source = sd_event_source_unref(m->dns_stub_tcp_event_source); | |
b30bf55d | 783 | } |