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