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623a4c97 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <netinet/tcp.h> | |
23 | ||
b5efdb8a | 24 | #include "alloc-util.h" |
3ffd4af2 | 25 | #include "fd-util.h" |
afc5dbf3 | 26 | #include "io-util.h" |
623a4c97 LP |
27 | #include "missing.h" |
28 | #include "resolved-dns-stream.h" | |
29 | ||
30 | #define DNS_STREAM_TIMEOUT_USEC (10 * USEC_PER_SEC) | |
31 | #define DNS_STREAMS_MAX 128 | |
32 | ||
33 | static void dns_stream_stop(DnsStream *s) { | |
34 | assert(s); | |
35 | ||
36 | s->io_event_source = sd_event_source_unref(s->io_event_source); | |
37 | s->timeout_event_source = sd_event_source_unref(s->timeout_event_source); | |
38 | s->fd = safe_close(s->fd); | |
39 | } | |
40 | ||
41 | static int dns_stream_update_io(DnsStream *s) { | |
42 | int f = 0; | |
43 | ||
44 | assert(s); | |
45 | ||
46 | if (s->write_packet && s->n_written < sizeof(s->write_size) + s->write_packet->size) | |
47 | f |= EPOLLOUT; | |
48 | if (!s->read_packet || s->n_read < sizeof(s->read_size) + s->read_packet->size) | |
49 | f |= EPOLLIN; | |
50 | ||
51 | return sd_event_source_set_io_events(s->io_event_source, f); | |
52 | } | |
53 | ||
b914e211 | 54 | static int dns_stream_complete(DnsStream *s, int error) { |
623a4c97 LP |
55 | assert(s); |
56 | ||
57 | dns_stream_stop(s); | |
58 | ||
59 | if (s->complete) | |
60 | s->complete(s, error); | |
61 | else | |
62 | dns_stream_free(s); | |
63 | ||
64 | return 0; | |
65 | } | |
66 | ||
b914e211 LP |
67 | static int dns_stream_identify(DnsStream *s) { |
68 | union { | |
69 | struct cmsghdr header; /* For alignment */ | |
40a1eebd | 70 | uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) |
b914e211 LP |
71 | + EXTRA_CMSG_SPACE /* kernel appears to require extra space */]; |
72 | } control; | |
73 | struct msghdr mh = {}; | |
74 | struct cmsghdr *cmsg; | |
75 | socklen_t sl; | |
76 | int r; | |
77 | ||
78 | assert(s); | |
79 | ||
80 | if (s->identified) | |
81 | return 0; | |
82 | ||
83 | /* Query the local side */ | |
84 | s->local_salen = sizeof(s->local); | |
85 | r = getsockname(s->fd, &s->local.sa, &s->local_salen); | |
86 | if (r < 0) | |
87 | return -errno; | |
88 | if (s->local.sa.sa_family == AF_INET6 && s->ifindex <= 0) | |
89 | s->ifindex = s->local.in6.sin6_scope_id; | |
90 | ||
91 | /* Query the remote side */ | |
92 | s->peer_salen = sizeof(s->peer); | |
93 | r = getpeername(s->fd, &s->peer.sa, &s->peer_salen); | |
94 | if (r < 0) | |
95 | return -errno; | |
96 | if (s->peer.sa.sa_family == AF_INET6 && s->ifindex <= 0) | |
97 | s->ifindex = s->peer.in6.sin6_scope_id; | |
98 | ||
99 | /* Check consistency */ | |
100 | assert(s->peer.sa.sa_family == s->local.sa.sa_family); | |
101 | assert(IN_SET(s->peer.sa.sa_family, AF_INET, AF_INET6)); | |
102 | ||
103 | /* Query connection meta information */ | |
104 | sl = sizeof(control); | |
105 | if (s->peer.sa.sa_family == AF_INET) { | |
106 | r = getsockopt(s->fd, IPPROTO_IP, IP_PKTOPTIONS, &control, &sl); | |
107 | if (r < 0) | |
108 | return -errno; | |
109 | } else if (s->peer.sa.sa_family == AF_INET6) { | |
110 | ||
111 | r = getsockopt(s->fd, IPPROTO_IPV6, IPV6_2292PKTOPTIONS, &control, &sl); | |
112 | if (r < 0) | |
113 | return -errno; | |
114 | } else | |
115 | return -EAFNOSUPPORT; | |
116 | ||
117 | mh.msg_control = &control; | |
118 | mh.msg_controllen = sl; | |
2a1288ff LP |
119 | |
120 | CMSG_FOREACH(cmsg, &mh) { | |
b914e211 LP |
121 | |
122 | if (cmsg->cmsg_level == IPPROTO_IPV6) { | |
123 | assert(s->peer.sa.sa_family == AF_INET6); | |
124 | ||
125 | switch (cmsg->cmsg_type) { | |
126 | ||
127 | case IPV6_PKTINFO: { | |
128 | struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg); | |
129 | ||
130 | if (s->ifindex <= 0) | |
131 | s->ifindex = i->ipi6_ifindex; | |
132 | break; | |
133 | } | |
134 | ||
135 | case IPV6_HOPLIMIT: | |
136 | s->ttl = *(int *) CMSG_DATA(cmsg); | |
137 | break; | |
138 | } | |
139 | ||
140 | } else if (cmsg->cmsg_level == IPPROTO_IP) { | |
141 | assert(s->peer.sa.sa_family == AF_INET); | |
142 | ||
143 | switch (cmsg->cmsg_type) { | |
144 | ||
145 | case IP_PKTINFO: { | |
146 | struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg); | |
147 | ||
148 | if (s->ifindex <= 0) | |
149 | s->ifindex = i->ipi_ifindex; | |
150 | break; | |
151 | } | |
152 | ||
153 | case IP_TTL: | |
154 | s->ttl = *(int *) CMSG_DATA(cmsg); | |
155 | break; | |
156 | } | |
157 | } | |
158 | } | |
159 | ||
160 | /* The Linux kernel sets the interface index to the loopback | |
161 | * device if the connection came from the local host since it | |
162 | * avoids the routing table in such a case. Let's unset the | |
163 | * interface index in such a case. */ | |
a5f03596 | 164 | if (s->ifindex == LOOPBACK_IFINDEX) |
b914e211 LP |
165 | s->ifindex = 0; |
166 | ||
167 | /* If we don't know the interface index still, we look for the | |
168 | * first local interface with a matching address. Yuck! */ | |
169 | if (s->ifindex <= 0) | |
170 | s->ifindex = manager_find_ifindex(s->manager, s->local.sa.sa_family, s->local.sa.sa_family == AF_INET ? (union in_addr_union*) &s->local.in.sin_addr : (union in_addr_union*) &s->local.in6.sin6_addr); | |
171 | ||
172 | if (s->protocol == DNS_PROTOCOL_LLMNR && s->ifindex > 0) { | |
173 | uint32_t ifindex = htobe32(s->ifindex); | |
174 | ||
175 | /* Make sure all packets for this connection are sent on the same interface */ | |
176 | if (s->local.sa.sa_family == AF_INET) { | |
177 | r = setsockopt(s->fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex)); | |
178 | if (r < 0) | |
56f64d95 | 179 | log_debug_errno(errno, "Failed to invoke IP_UNICAST_IF: %m"); |
b914e211 LP |
180 | } else if (s->local.sa.sa_family == AF_INET6) { |
181 | r = setsockopt(s->fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex)); | |
182 | if (r < 0) | |
56f64d95 | 183 | log_debug_errno(errno, "Failed to invoke IPV6_UNICAST_IF: %m"); |
b914e211 LP |
184 | } |
185 | } | |
186 | ||
187 | s->identified = true; | |
188 | ||
189 | return 0; | |
190 | } | |
191 | ||
623a4c97 LP |
192 | static int on_stream_timeout(sd_event_source *es, usec_t usec, void *userdata) { |
193 | DnsStream *s = userdata; | |
194 | ||
195 | assert(s); | |
196 | ||
b914e211 | 197 | return dns_stream_complete(s, ETIMEDOUT); |
623a4c97 LP |
198 | } |
199 | ||
200 | static int on_stream_io(sd_event_source *es, int fd, uint32_t revents, void *userdata) { | |
201 | DnsStream *s = userdata; | |
202 | int r; | |
203 | ||
204 | assert(s); | |
205 | ||
b914e211 LP |
206 | r = dns_stream_identify(s); |
207 | if (r < 0) | |
208 | return dns_stream_complete(s, -r); | |
209 | ||
623a4c97 LP |
210 | if ((revents & EPOLLOUT) && |
211 | s->write_packet && | |
212 | s->n_written < sizeof(s->write_size) + s->write_packet->size) { | |
213 | ||
214 | struct iovec iov[2]; | |
215 | ssize_t ss; | |
216 | ||
217 | iov[0].iov_base = &s->write_size; | |
218 | iov[0].iov_len = sizeof(s->write_size); | |
219 | iov[1].iov_base = DNS_PACKET_DATA(s->write_packet); | |
220 | iov[1].iov_len = s->write_packet->size; | |
221 | ||
222 | IOVEC_INCREMENT(iov, 2, s->n_written); | |
223 | ||
224 | ss = writev(fd, iov, 2); | |
225 | if (ss < 0) { | |
226 | if (errno != EINTR && errno != EAGAIN) | |
b914e211 | 227 | return dns_stream_complete(s, errno); |
623a4c97 LP |
228 | } else |
229 | s->n_written += ss; | |
230 | ||
231 | /* Are we done? If so, disable the event source for EPOLLOUT */ | |
232 | if (s->n_written >= sizeof(s->write_size) + s->write_packet->size) { | |
233 | r = dns_stream_update_io(s); | |
234 | if (r < 0) | |
b914e211 | 235 | return dns_stream_complete(s, -r); |
623a4c97 LP |
236 | } |
237 | } | |
238 | ||
239 | if ((revents & (EPOLLIN|EPOLLHUP|EPOLLRDHUP)) && | |
240 | (!s->read_packet || | |
241 | s->n_read < sizeof(s->read_size) + s->read_packet->size)) { | |
242 | ||
243 | if (s->n_read < sizeof(s->read_size)) { | |
244 | ssize_t ss; | |
245 | ||
246 | ss = read(fd, (uint8_t*) &s->read_size + s->n_read, sizeof(s->read_size) - s->n_read); | |
247 | if (ss < 0) { | |
248 | if (errno != EINTR && errno != EAGAIN) | |
b914e211 | 249 | return dns_stream_complete(s, errno); |
623a4c97 | 250 | } else if (ss == 0) |
b914e211 | 251 | return dns_stream_complete(s, ECONNRESET); |
623a4c97 LP |
252 | else |
253 | s->n_read += ss; | |
254 | } | |
255 | ||
256 | if (s->n_read >= sizeof(s->read_size)) { | |
257 | ||
258 | if (be16toh(s->read_size) < DNS_PACKET_HEADER_SIZE) | |
b914e211 | 259 | return dns_stream_complete(s, EBADMSG); |
623a4c97 LP |
260 | |
261 | if (s->n_read < sizeof(s->read_size) + be16toh(s->read_size)) { | |
262 | ssize_t ss; | |
263 | ||
264 | if (!s->read_packet) { | |
265 | r = dns_packet_new(&s->read_packet, s->protocol, be16toh(s->read_size)); | |
266 | if (r < 0) | |
b914e211 | 267 | return dns_stream_complete(s, -r); |
623a4c97 LP |
268 | |
269 | s->read_packet->size = be16toh(s->read_size); | |
270 | s->read_packet->ipproto = IPPROTO_TCP; | |
271 | s->read_packet->family = s->peer.sa.sa_family; | |
272 | s->read_packet->ttl = s->ttl; | |
273 | s->read_packet->ifindex = s->ifindex; | |
274 | ||
275 | if (s->read_packet->family == AF_INET) { | |
276 | s->read_packet->sender.in = s->peer.in.sin_addr; | |
277 | s->read_packet->sender_port = be16toh(s->peer.in.sin_port); | |
278 | s->read_packet->destination.in = s->local.in.sin_addr; | |
279 | s->read_packet->destination_port = be16toh(s->local.in.sin_port); | |
280 | } else { | |
281 | assert(s->read_packet->family == AF_INET6); | |
282 | s->read_packet->sender.in6 = s->peer.in6.sin6_addr; | |
283 | s->read_packet->sender_port = be16toh(s->peer.in6.sin6_port); | |
284 | s->read_packet->destination.in6 = s->local.in6.sin6_addr; | |
285 | s->read_packet->destination_port = be16toh(s->local.in6.sin6_port); | |
286 | ||
287 | if (s->read_packet->ifindex == 0) | |
288 | s->read_packet->ifindex = s->peer.in6.sin6_scope_id; | |
289 | if (s->read_packet->ifindex == 0) | |
290 | s->read_packet->ifindex = s->local.in6.sin6_scope_id; | |
291 | } | |
292 | } | |
293 | ||
294 | ss = read(fd, | |
295 | (uint8_t*) DNS_PACKET_DATA(s->read_packet) + s->n_read - sizeof(s->read_size), | |
296 | sizeof(s->read_size) + be16toh(s->read_size) - s->n_read); | |
297 | if (ss < 0) { | |
298 | if (errno != EINTR && errno != EAGAIN) | |
b914e211 | 299 | return dns_stream_complete(s, errno); |
623a4c97 | 300 | } else if (ss == 0) |
b914e211 | 301 | return dns_stream_complete(s, ECONNRESET); |
623a4c97 LP |
302 | else |
303 | s->n_read += ss; | |
304 | } | |
305 | ||
306 | /* Are we done? If so, disable the event source for EPOLLIN */ | |
307 | if (s->n_read >= sizeof(s->read_size) + be16toh(s->read_size)) { | |
308 | r = dns_stream_update_io(s); | |
309 | if (r < 0) | |
b914e211 | 310 | return dns_stream_complete(s, -r); |
623a4c97 LP |
311 | |
312 | /* If there's a packet handler | |
313 | * installed, call that. Note that | |
314 | * this is optional... */ | |
315 | if (s->on_packet) | |
316 | return s->on_packet(s); | |
317 | } | |
318 | } | |
319 | } | |
320 | ||
321 | if ((s->write_packet && s->n_written >= sizeof(s->write_size) + s->write_packet->size) && | |
322 | (s->read_packet && s->n_read >= sizeof(s->read_size) + s->read_packet->size)) | |
b914e211 | 323 | return dns_stream_complete(s, 0); |
623a4c97 LP |
324 | |
325 | return 0; | |
326 | } | |
327 | ||
328 | DnsStream *dns_stream_free(DnsStream *s) { | |
329 | if (!s) | |
330 | return NULL; | |
331 | ||
332 | dns_stream_stop(s); | |
333 | ||
334 | if (s->manager) { | |
335 | LIST_REMOVE(streams, s->manager->dns_streams, s); | |
336 | s->manager->n_dns_streams--; | |
337 | } | |
338 | ||
339 | dns_packet_unref(s->write_packet); | |
340 | dns_packet_unref(s->read_packet); | |
341 | ||
342 | free(s); | |
343 | ||
344 | return 0; | |
345 | } | |
346 | ||
347 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsStream*, dns_stream_free); | |
348 | ||
349 | int dns_stream_new(Manager *m, DnsStream **ret, DnsProtocol protocol, int fd) { | |
623a4c97 | 350 | _cleanup_(dns_stream_freep) DnsStream *s = NULL; |
623a4c97 LP |
351 | int r; |
352 | ||
353 | assert(m); | |
354 | assert(fd >= 0); | |
355 | ||
356 | if (m->n_dns_streams > DNS_STREAMS_MAX) | |
357 | return -EBUSY; | |
358 | ||
359 | s = new0(DnsStream, 1); | |
360 | if (!s) | |
361 | return -ENOMEM; | |
362 | ||
363 | s->fd = -1; | |
364 | s->protocol = protocol; | |
365 | ||
623a4c97 LP |
366 | r = sd_event_add_io(m->event, &s->io_event_source, fd, EPOLLIN, on_stream_io, s); |
367 | if (r < 0) | |
368 | return r; | |
369 | ||
aa4a9deb LP |
370 | (void) sd_event_source_set_description(s->io_event_source, "dns-stream-io"); |
371 | ||
9a015429 LP |
372 | r = sd_event_add_time( |
373 | m->event, | |
374 | &s->timeout_event_source, | |
375 | clock_boottime_or_monotonic(), | |
376 | now(clock_boottime_or_monotonic()) + DNS_STREAM_TIMEOUT_USEC, 0, | |
377 | on_stream_timeout, s); | |
623a4c97 LP |
378 | if (r < 0) |
379 | return r; | |
380 | ||
aa4a9deb LP |
381 | (void) sd_event_source_set_description(s->timeout_event_source, "dns-stream-timeout"); |
382 | ||
623a4c97 LP |
383 | LIST_PREPEND(streams, m->dns_streams, s); |
384 | s->manager = m; | |
385 | s->fd = fd; | |
386 | m->n_dns_streams++; | |
387 | ||
388 | *ret = s; | |
389 | s = NULL; | |
390 | ||
391 | return 0; | |
392 | } | |
393 | ||
394 | int dns_stream_write_packet(DnsStream *s, DnsPacket *p) { | |
395 | assert(s); | |
396 | ||
397 | if (s->write_packet) | |
398 | return -EBUSY; | |
399 | ||
400 | s->write_packet = dns_packet_ref(p); | |
401 | s->write_size = htobe16(p->size); | |
402 | s->n_written = 0; | |
403 | ||
404 | return dns_stream_update_io(s); | |
405 | } |