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89489ef7 TG |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2013 Tom Gundersen <teg@jklm.no> | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
18 | ***/ | |
19 | ||
20 | #include <netinet/in.h> | |
21 | #include <stdbool.h> | |
22 | #include <unistd.h> | |
23 | ||
07630cea LP |
24 | #include "sd-netlink.h" |
25 | ||
b5efdb8a | 26 | #include "alloc-util.h" |
89489ef7 | 27 | #include "formats-util.h" |
89489ef7 | 28 | #include "missing.h" |
89489ef7 TG |
29 | #include "netlink-internal.h" |
30 | #include "netlink-types.h" | |
07630cea LP |
31 | #include "netlink-util.h" |
32 | #include "refcnt.h" | |
33 | #include "socket-util.h" | |
34 | #include "util.h" | |
89489ef7 | 35 | |
b95cc756 TG |
36 | int socket_open(int family) { |
37 | int fd; | |
38 | ||
39 | fd = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, family); | |
40 | if (fd < 0) | |
41 | return -errno; | |
42 | ||
43 | return fd; | |
44 | } | |
45 | ||
9c5a882b TG |
46 | static int broadcast_groups_get(sd_netlink *nl) { |
47 | _cleanup_free_ uint32_t *groups = NULL; | |
48 | socklen_t len = 0, old_len; | |
49 | unsigned i, j; | |
50 | int r; | |
51 | ||
52 | assert(nl); | |
f78bc916 | 53 | assert(nl->fd >= 0); |
9c5a882b TG |
54 | |
55 | r = getsockopt(nl->fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, NULL, &len); | |
56 | if (r < 0) { | |
57 | if (errno == ENOPROTOOPT) { | |
58 | nl->broadcast_group_dont_leave = true; | |
59 | return 0; | |
60 | } else | |
61 | return -errno; | |
62 | } | |
63 | ||
64 | if (len == 0) | |
65 | return 0; | |
66 | ||
67 | groups = new0(uint32_t, len); | |
68 | if (!groups) | |
69 | return -ENOMEM; | |
70 | ||
71 | old_len = len; | |
72 | ||
73 | r = getsockopt(nl->fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, groups, &len); | |
74 | if (r < 0) | |
75 | return -errno; | |
76 | ||
77 | if (old_len != len) | |
78 | return -EIO; | |
79 | ||
80 | r = hashmap_ensure_allocated(&nl->broadcast_group_refs, NULL); | |
81 | if (r < 0) | |
82 | return r; | |
83 | ||
84 | for (i = 0; i < len; i++) { | |
85 | for (j = 0; j < sizeof(uint32_t) * 8; j ++) { | |
86 | uint32_t offset; | |
87 | unsigned group; | |
88 | ||
89 | offset = 1U << j; | |
90 | ||
91 | if (!(groups[i] & offset)) | |
92 | continue; | |
93 | ||
94 | group = i * sizeof(uint32_t) * 8 + j + 1; | |
95 | ||
96 | r = hashmap_put(nl->broadcast_group_refs, UINT_TO_PTR(group), UINT_TO_PTR(1)); | |
97 | if (r < 0) | |
98 | return r; | |
99 | } | |
100 | } | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
b95cc756 TG |
105 | int socket_bind(sd_netlink *nl) { |
106 | socklen_t addrlen; | |
107 | int r, one = 1; | |
108 | ||
109 | r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_PKTINFO, &one, sizeof(one)); | |
110 | if (r < 0) | |
111 | return -errno; | |
112 | ||
113 | addrlen = sizeof(nl->sockaddr); | |
114 | ||
115 | r = bind(nl->fd, &nl->sockaddr.sa, addrlen); | |
116 | /* ignore EINVAL to allow opening an already bound socket */ | |
117 | if (r < 0 && errno != EINVAL) | |
118 | return -errno; | |
119 | ||
120 | r = getsockname(nl->fd, &nl->sockaddr.sa, &addrlen); | |
121 | if (r < 0) | |
122 | return -errno; | |
123 | ||
9c5a882b TG |
124 | r = broadcast_groups_get(nl); |
125 | if (r < 0) | |
126 | return r; | |
127 | ||
b95cc756 TG |
128 | return 0; |
129 | } | |
130 | ||
9c5a882b TG |
131 | static unsigned broadcast_group_get_ref(sd_netlink *nl, unsigned group) { |
132 | assert(nl); | |
133 | ||
134 | return PTR_TO_UINT(hashmap_get(nl->broadcast_group_refs, UINT_TO_PTR(group))); | |
135 | } | |
136 | ||
137 | static int broadcast_group_set_ref(sd_netlink *nl, unsigned group, unsigned n_ref) { | |
138 | int r; | |
139 | ||
140 | assert(nl); | |
141 | ||
142 | r = hashmap_replace(nl->broadcast_group_refs, UINT_TO_PTR(group), UINT_TO_PTR(n_ref)); | |
143 | if (r < 0) | |
144 | return r; | |
145 | ||
146 | return 0; | |
147 | } | |
b95cc756 | 148 | |
9c5a882b | 149 | static int broadcast_group_join(sd_netlink *nl, unsigned group) { |
b95cc756 TG |
150 | int r; |
151 | ||
152 | assert(nl); | |
153 | assert(nl->fd >= 0); | |
154 | assert(group > 0); | |
155 | ||
156 | r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group)); | |
157 | if (r < 0) | |
158 | return -errno; | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
9c5a882b TG |
163 | int socket_broadcast_group_ref(sd_netlink *nl, unsigned group) { |
164 | unsigned n_ref; | |
165 | int r; | |
166 | ||
167 | assert(nl); | |
168 | ||
169 | n_ref = broadcast_group_get_ref(nl, group); | |
170 | ||
171 | n_ref ++; | |
172 | ||
173 | r = hashmap_ensure_allocated(&nl->broadcast_group_refs, NULL); | |
174 | if (r < 0) | |
175 | return r; | |
176 | ||
177 | r = broadcast_group_set_ref(nl, group, n_ref); | |
178 | if (r < 0) | |
179 | return r; | |
180 | ||
181 | if (n_ref > 1) | |
182 | /* not yet in the group */ | |
183 | return 0; | |
184 | ||
185 | r = broadcast_group_join(nl, group); | |
186 | if (r < 0) | |
187 | return r; | |
188 | ||
189 | return 0; | |
190 | } | |
191 | ||
192 | static int broadcast_group_leave(sd_netlink *nl, unsigned group) { | |
193 | int r; | |
194 | ||
195 | assert(nl); | |
196 | assert(nl->fd >= 0); | |
197 | assert(group > 0); | |
198 | ||
199 | if (nl->broadcast_group_dont_leave) | |
200 | return 0; | |
201 | ||
202 | r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, &group, sizeof(group)); | |
203 | if (r < 0) | |
204 | return -errno; | |
205 | ||
206 | return 0; | |
207 | } | |
208 | ||
209 | int socket_broadcast_group_unref(sd_netlink *nl, unsigned group) { | |
210 | unsigned n_ref; | |
211 | int r; | |
212 | ||
213 | assert(nl); | |
214 | ||
215 | n_ref = broadcast_group_get_ref(nl, group); | |
216 | ||
217 | assert(n_ref > 0); | |
218 | ||
219 | n_ref --; | |
220 | ||
221 | r = broadcast_group_set_ref(nl, group, n_ref); | |
222 | if (r < 0) | |
223 | return r; | |
224 | ||
225 | if (n_ref > 0) | |
226 | /* still refs left */ | |
227 | return 0; | |
228 | ||
229 | r = broadcast_group_leave(nl, group); | |
230 | if (r < 0) | |
231 | return r; | |
232 | ||
233 | return 0; | |
234 | } | |
235 | ||
89489ef7 TG |
236 | /* returns the number of bytes sent, or a negative error code */ |
237 | int socket_write_message(sd_netlink *nl, sd_netlink_message *m) { | |
238 | union { | |
239 | struct sockaddr sa; | |
240 | struct sockaddr_nl nl; | |
241 | } addr = { | |
242 | .nl.nl_family = AF_NETLINK, | |
243 | }; | |
244 | ssize_t k; | |
245 | ||
246 | assert(nl); | |
247 | assert(m); | |
248 | assert(m->hdr); | |
249 | ||
250 | k = sendto(nl->fd, m->hdr, m->hdr->nlmsg_len, | |
251 | 0, &addr.sa, sizeof(addr)); | |
252 | if (k < 0) | |
253 | return -errno; | |
254 | ||
255 | return k; | |
256 | } | |
257 | ||
258 | static int socket_recv_message(int fd, struct iovec *iov, uint32_t *_group, bool peek) { | |
259 | union sockaddr_union sender; | |
260 | uint8_t cmsg_buffer[CMSG_SPACE(sizeof(struct nl_pktinfo))]; | |
261 | struct msghdr msg = { | |
262 | .msg_iov = iov, | |
263 | .msg_iovlen = 1, | |
264 | .msg_name = &sender, | |
265 | .msg_namelen = sizeof(sender), | |
266 | .msg_control = cmsg_buffer, | |
267 | .msg_controllen = sizeof(cmsg_buffer), | |
268 | }; | |
269 | struct cmsghdr *cmsg; | |
270 | uint32_t group = 0; | |
271 | int r; | |
272 | ||
273 | assert(fd >= 0); | |
274 | assert(iov); | |
275 | ||
276 | r = recvmsg(fd, &msg, MSG_TRUNC | (peek ? MSG_PEEK : 0)); | |
277 | if (r < 0) { | |
278 | /* no data */ | |
279 | if (errno == ENOBUFS) | |
280 | log_debug("rtnl: kernel receive buffer overrun"); | |
281 | else if (errno == EAGAIN) | |
282 | log_debug("rtnl: no data in socket"); | |
283 | ||
284 | return (errno == EAGAIN || errno == EINTR) ? 0 : -errno; | |
285 | } | |
286 | ||
287 | if (sender.nl.nl_pid != 0) { | |
288 | /* not from the kernel, ignore */ | |
289 | log_debug("rtnl: ignoring message from portid %"PRIu32, sender.nl.nl_pid); | |
290 | ||
291 | if (peek) { | |
292 | /* drop the message */ | |
293 | r = recvmsg(fd, &msg, 0); | |
294 | if (r < 0) | |
295 | return (errno == EAGAIN || errno == EINTR) ? 0 : -errno; | |
296 | } | |
297 | ||
298 | return 0; | |
299 | } | |
300 | ||
301 | CMSG_FOREACH(cmsg, &msg) { | |
302 | if (cmsg->cmsg_level == SOL_NETLINK && | |
303 | cmsg->cmsg_type == NETLINK_PKTINFO && | |
304 | cmsg->cmsg_len == CMSG_LEN(sizeof(struct nl_pktinfo))) { | |
305 | struct nl_pktinfo *pktinfo = (void *)CMSG_DATA(cmsg); | |
306 | ||
307 | /* multi-cast group */ | |
308 | group = pktinfo->group; | |
309 | } | |
310 | } | |
311 | ||
312 | if (_group) | |
313 | *_group = group; | |
314 | ||
315 | return r; | |
316 | } | |
317 | ||
318 | /* On success, the number of bytes received is returned and *ret points to the received message | |
319 | * which has a valid header and the correct size. | |
320 | * If nothing useful was received 0 is returned. | |
321 | * On failure, a negative error code is returned. | |
322 | */ | |
323 | int socket_read_message(sd_netlink *rtnl) { | |
4afd3348 | 324 | _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *first = NULL; |
89489ef7 TG |
325 | struct iovec iov = {}; |
326 | uint32_t group = 0; | |
327 | bool multi_part = false, done = false; | |
328 | struct nlmsghdr *new_msg; | |
329 | size_t len; | |
330 | int r; | |
331 | unsigned i = 0; | |
332 | ||
333 | assert(rtnl); | |
334 | assert(rtnl->rbuffer); | |
335 | assert(rtnl->rbuffer_allocated >= sizeof(struct nlmsghdr)); | |
336 | ||
337 | /* read nothing, just get the pending message size */ | |
338 | r = socket_recv_message(rtnl->fd, &iov, NULL, true); | |
339 | if (r <= 0) | |
340 | return r; | |
341 | else | |
342 | len = (size_t)r; | |
343 | ||
344 | /* make room for the pending message */ | |
345 | if (!greedy_realloc((void **)&rtnl->rbuffer, | |
346 | &rtnl->rbuffer_allocated, | |
347 | len, sizeof(uint8_t))) | |
348 | return -ENOMEM; | |
349 | ||
350 | iov.iov_base = rtnl->rbuffer; | |
351 | iov.iov_len = rtnl->rbuffer_allocated; | |
352 | ||
353 | /* read the pending message */ | |
354 | r = socket_recv_message(rtnl->fd, &iov, &group, false); | |
355 | if (r <= 0) | |
356 | return r; | |
357 | else | |
358 | len = (size_t)r; | |
359 | ||
360 | if (len > rtnl->rbuffer_allocated) | |
361 | /* message did not fit in read buffer */ | |
362 | return -EIO; | |
363 | ||
364 | if (NLMSG_OK(rtnl->rbuffer, len) && rtnl->rbuffer->nlmsg_flags & NLM_F_MULTI) { | |
365 | multi_part = true; | |
366 | ||
367 | for (i = 0; i < rtnl->rqueue_partial_size; i++) { | |
368 | if (rtnl_message_get_serial(rtnl->rqueue_partial[i]) == | |
369 | rtnl->rbuffer->nlmsg_seq) { | |
370 | first = rtnl->rqueue_partial[i]; | |
371 | break; | |
372 | } | |
373 | } | |
374 | } | |
375 | ||
376 | for (new_msg = rtnl->rbuffer; NLMSG_OK(new_msg, len) && !done; new_msg = NLMSG_NEXT(new_msg, len)) { | |
4afd3348 | 377 | _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL; |
89489ef7 TG |
378 | const NLType *nl_type; |
379 | ||
380 | if (!group && new_msg->nlmsg_pid != rtnl->sockaddr.nl.nl_pid) | |
381 | /* not broadcast and not for us */ | |
382 | continue; | |
383 | ||
384 | if (new_msg->nlmsg_type == NLMSG_NOOP) | |
385 | /* silently drop noop messages */ | |
386 | continue; | |
387 | ||
388 | if (new_msg->nlmsg_type == NLMSG_DONE) { | |
389 | /* finished reading multi-part message */ | |
390 | done = true; | |
391 | ||
392 | /* if first is not defined, put NLMSG_DONE into the receive queue. */ | |
393 | if (first) | |
394 | continue; | |
395 | } | |
396 | ||
397 | /* check that we support this message type */ | |
846a6b3d | 398 | r = type_system_get_type(&type_system_root, &nl_type, new_msg->nlmsg_type); |
89489ef7 TG |
399 | if (r < 0) { |
400 | if (r == -EOPNOTSUPP) | |
401 | log_debug("sd-netlink: ignored message with unknown type: %i", | |
402 | new_msg->nlmsg_type); | |
403 | ||
404 | continue; | |
405 | } | |
406 | ||
407 | /* check that the size matches the message type */ | |
817d1cd8 | 408 | if (new_msg->nlmsg_len < NLMSG_LENGTH(type_get_size(nl_type))) { |
89489ef7 TG |
409 | log_debug("sd-netlink: message larger than expected, dropping"); |
410 | continue; | |
411 | } | |
412 | ||
413 | r = message_new_empty(rtnl, &m); | |
414 | if (r < 0) | |
415 | return r; | |
416 | ||
417 | m->broadcast = !!group; | |
418 | ||
419 | m->hdr = memdup(new_msg, new_msg->nlmsg_len); | |
420 | if (!m->hdr) | |
421 | return -ENOMEM; | |
422 | ||
423 | /* seal and parse the top-level message */ | |
424 | r = sd_netlink_message_rewind(m); | |
425 | if (r < 0) | |
426 | return r; | |
427 | ||
428 | /* push the message onto the multi-part message stack */ | |
429 | if (first) | |
430 | m->next = first; | |
431 | first = m; | |
432 | m = NULL; | |
433 | } | |
434 | ||
435 | if (len) | |
436 | log_debug("sd-netlink: discarding %zu bytes of incoming message", len); | |
437 | ||
438 | if (!first) | |
439 | return 0; | |
440 | ||
441 | if (!multi_part || done) { | |
442 | /* we got a complete message, push it on the read queue */ | |
443 | r = rtnl_rqueue_make_room(rtnl); | |
444 | if (r < 0) | |
445 | return r; | |
446 | ||
447 | rtnl->rqueue[rtnl->rqueue_size ++] = first; | |
448 | first = NULL; | |
449 | ||
450 | if (multi_part && (i < rtnl->rqueue_partial_size)) { | |
451 | /* remove the message form the partial read queue */ | |
452 | memmove(rtnl->rqueue_partial + i,rtnl->rqueue_partial + i + 1, | |
453 | sizeof(sd_netlink_message*) * (rtnl->rqueue_partial_size - i - 1)); | |
454 | rtnl->rqueue_partial_size --; | |
455 | } | |
456 | ||
457 | return 1; | |
458 | } else { | |
459 | /* we only got a partial multi-part message, push it on the | |
460 | partial read queue */ | |
461 | if (i < rtnl->rqueue_partial_size) { | |
462 | rtnl->rqueue_partial[i] = first; | |
463 | } else { | |
464 | r = rtnl_rqueue_partial_make_room(rtnl); | |
465 | if (r < 0) | |
466 | return r; | |
467 | ||
468 | rtnl->rqueue_partial[rtnl->rqueue_partial_size ++] = first; | |
469 | } | |
470 | first = NULL; | |
471 | ||
472 | return 0; | |
473 | } | |
474 | } |