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aba5acdf SH |
1 | /* |
2 | * libnetlink.c RTnetlink service routines. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | * | |
9 | * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <stdio.h> | |
14 | #include <stdlib.h> | |
15 | #include <unistd.h> | |
16 | #include <syslog.h> | |
17 | #include <fcntl.h> | |
18 | #include <net/if_arp.h> | |
19 | #include <sys/socket.h> | |
20 | #include <netinet/in.h> | |
21 | #include <string.h> | |
22 | #include <errno.h> | |
23 | #include <time.h> | |
24 | #include <sys/uio.h> | |
25 | ||
26 | #include "libnetlink.h" | |
27 | ||
28 | void rtnl_close(struct rtnl_handle *rth) | |
29 | { | |
30 | close(rth->fd); | |
31 | } | |
32 | ||
33 | int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions) | |
34 | { | |
35 | int addr_len; | |
36 | ||
37 | memset(rth, 0, sizeof(rth)); | |
38 | ||
39 | rth->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); | |
40 | if (rth->fd < 0) { | |
41 | perror("Cannot open netlink socket"); | |
42 | return -1; | |
43 | } | |
44 | ||
45 | memset(&rth->local, 0, sizeof(rth->local)); | |
46 | rth->local.nl_family = AF_NETLINK; | |
47 | rth->local.nl_groups = subscriptions; | |
48 | ||
49 | if (bind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local)) < 0) { | |
50 | perror("Cannot bind netlink socket"); | |
51 | return -1; | |
52 | } | |
53 | addr_len = sizeof(rth->local); | |
54 | if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) { | |
55 | perror("Cannot getsockname"); | |
56 | return -1; | |
57 | } | |
58 | if (addr_len != sizeof(rth->local)) { | |
59 | fprintf(stderr, "Wrong address length %d\n", addr_len); | |
60 | return -1; | |
61 | } | |
62 | if (rth->local.nl_family != AF_NETLINK) { | |
63 | fprintf(stderr, "Wrong address family %d\n", rth->local.nl_family); | |
64 | return -1; | |
65 | } | |
66 | rth->seq = time(NULL); | |
67 | return 0; | |
68 | } | |
69 | ||
70 | int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type) | |
71 | { | |
72 | struct { | |
73 | struct nlmsghdr nlh; | |
74 | struct rtgenmsg g; | |
75 | } req; | |
76 | struct sockaddr_nl nladdr; | |
77 | ||
78 | memset(&nladdr, 0, sizeof(nladdr)); | |
79 | nladdr.nl_family = AF_NETLINK; | |
80 | ||
81 | req.nlh.nlmsg_len = sizeof(req); | |
82 | req.nlh.nlmsg_type = type; | |
83 | req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST; | |
84 | req.nlh.nlmsg_pid = 0; | |
85 | req.nlh.nlmsg_seq = rth->dump = ++rth->seq; | |
86 | req.g.rtgen_family = family; | |
87 | ||
88 | return sendto(rth->fd, (void*)&req, sizeof(req), 0, (struct sockaddr*)&nladdr, sizeof(nladdr)); | |
89 | } | |
90 | ||
91 | int rtnl_send(struct rtnl_handle *rth, char *buf, int len) | |
92 | { | |
93 | struct sockaddr_nl nladdr; | |
94 | ||
95 | memset(&nladdr, 0, sizeof(nladdr)); | |
96 | nladdr.nl_family = AF_NETLINK; | |
97 | ||
98 | return sendto(rth->fd, buf, len, 0, (struct sockaddr*)&nladdr, sizeof(nladdr)); | |
99 | } | |
100 | ||
101 | int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) | |
102 | { | |
103 | struct nlmsghdr nlh; | |
104 | struct sockaddr_nl nladdr; | |
105 | struct iovec iov[2] = { { &nlh, sizeof(nlh) }, { req, len } }; | |
106 | struct msghdr msg = { | |
107 | (void*)&nladdr, sizeof(nladdr), | |
108 | iov, 2, | |
109 | NULL, 0, | |
110 | 0 | |
111 | }; | |
112 | ||
113 | memset(&nladdr, 0, sizeof(nladdr)); | |
114 | nladdr.nl_family = AF_NETLINK; | |
115 | ||
116 | nlh.nlmsg_len = NLMSG_LENGTH(len); | |
117 | nlh.nlmsg_type = type; | |
118 | nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST; | |
119 | nlh.nlmsg_pid = 0; | |
120 | nlh.nlmsg_seq = rth->dump = ++rth->seq; | |
121 | ||
122 | return sendmsg(rth->fd, &msg, 0); | |
123 | } | |
124 | ||
125 | int rtnl_dump_filter(struct rtnl_handle *rth, | |
126 | int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *), | |
127 | void *arg1, | |
128 | int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *), | |
129 | void *arg2) | |
130 | { | |
131 | char buf[8192]; | |
132 | struct sockaddr_nl nladdr; | |
133 | struct iovec iov = { buf, sizeof(buf) }; | |
134 | ||
135 | while (1) { | |
136 | int status; | |
137 | struct nlmsghdr *h; | |
138 | ||
139 | struct msghdr msg = { | |
140 | (void*)&nladdr, sizeof(nladdr), | |
141 | &iov, 1, | |
142 | NULL, 0, | |
143 | 0 | |
144 | }; | |
145 | ||
146 | status = recvmsg(rth->fd, &msg, 0); | |
147 | ||
148 | if (status < 0) { | |
149 | if (errno == EINTR) | |
150 | continue; | |
151 | perror("OVERRUN"); | |
152 | continue; | |
153 | } | |
154 | if (status == 0) { | |
155 | fprintf(stderr, "EOF on netlink\n"); | |
156 | return -1; | |
157 | } | |
158 | if (msg.msg_namelen != sizeof(nladdr)) { | |
159 | fprintf(stderr, "sender address length == %d\n", msg.msg_namelen); | |
160 | exit(1); | |
161 | } | |
162 | ||
163 | h = (struct nlmsghdr*)buf; | |
164 | while (NLMSG_OK(h, status)) { | |
165 | int err; | |
166 | ||
167 | if (h->nlmsg_pid != rth->local.nl_pid || | |
168 | h->nlmsg_seq != rth->dump) { | |
169 | if (junk) { | |
170 | err = junk(&nladdr, h, arg2); | |
171 | if (err < 0) | |
172 | return err; | |
173 | } | |
174 | goto skip_it; | |
175 | } | |
176 | ||
177 | if (h->nlmsg_type == NLMSG_DONE) | |
178 | return 0; | |
179 | if (h->nlmsg_type == NLMSG_ERROR) { | |
180 | struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h); | |
181 | if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) { | |
182 | fprintf(stderr, "ERROR truncated\n"); | |
183 | } else { | |
184 | errno = -err->error; | |
185 | perror("RTNETLINK answers"); | |
186 | } | |
187 | return -1; | |
188 | } | |
189 | err = filter(&nladdr, h, arg1); | |
190 | if (err < 0) | |
191 | return err; | |
192 | ||
193 | skip_it: | |
194 | h = NLMSG_NEXT(h, status); | |
195 | } | |
196 | if (msg.msg_flags & MSG_TRUNC) { | |
197 | fprintf(stderr, "Message truncated\n"); | |
198 | continue; | |
199 | } | |
200 | if (status) { | |
201 | fprintf(stderr, "!!!Remnant of size %d\n", status); | |
202 | exit(1); | |
203 | } | |
204 | } | |
205 | } | |
206 | ||
207 | int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer, | |
208 | unsigned groups, struct nlmsghdr *answer, | |
209 | int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *), | |
210 | void *jarg) | |
211 | { | |
212 | int status; | |
213 | unsigned seq; | |
214 | struct nlmsghdr *h; | |
215 | struct sockaddr_nl nladdr; | |
216 | struct iovec iov = { (void*)n, n->nlmsg_len }; | |
217 | char buf[8192]; | |
218 | struct msghdr msg = { | |
219 | (void*)&nladdr, sizeof(nladdr), | |
220 | &iov, 1, | |
221 | NULL, 0, | |
222 | 0 | |
223 | }; | |
224 | ||
225 | memset(&nladdr, 0, sizeof(nladdr)); | |
226 | nladdr.nl_family = AF_NETLINK; | |
227 | nladdr.nl_pid = peer; | |
228 | nladdr.nl_groups = groups; | |
229 | ||
230 | n->nlmsg_seq = seq = ++rtnl->seq; | |
231 | if (answer == NULL) | |
232 | n->nlmsg_flags |= NLM_F_ACK; | |
233 | ||
234 | status = sendmsg(rtnl->fd, &msg, 0); | |
235 | ||
236 | if (status < 0) { | |
237 | perror("Cannot talk to rtnetlink"); | |
238 | return -1; | |
239 | } | |
240 | ||
241 | iov.iov_base = buf; | |
242 | ||
243 | while (1) { | |
244 | iov.iov_len = sizeof(buf); | |
245 | status = recvmsg(rtnl->fd, &msg, 0); | |
246 | ||
247 | if (status < 0) { | |
248 | if (errno == EINTR) | |
249 | continue; | |
250 | perror("OVERRUN"); | |
251 | continue; | |
252 | } | |
253 | if (status == 0) { | |
254 | fprintf(stderr, "EOF on netlink\n"); | |
255 | return -1; | |
256 | } | |
257 | if (msg.msg_namelen != sizeof(nladdr)) { | |
258 | fprintf(stderr, "sender address length == %d\n", msg.msg_namelen); | |
259 | exit(1); | |
260 | } | |
261 | for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) { | |
262 | int err; | |
263 | int len = h->nlmsg_len; | |
264 | int l = len - sizeof(*h); | |
265 | ||
266 | if (l<0 || len>status) { | |
267 | if (msg.msg_flags & MSG_TRUNC) { | |
268 | fprintf(stderr, "Truncated message\n"); | |
269 | return -1; | |
270 | } | |
271 | fprintf(stderr, "!!!malformed message: len=%d\n", len); | |
272 | exit(1); | |
273 | } | |
274 | ||
275 | if (h->nlmsg_pid != rtnl->local.nl_pid || | |
276 | h->nlmsg_seq != seq) { | |
277 | if (junk) { | |
278 | err = junk(&nladdr, h, jarg); | |
279 | if (err < 0) | |
280 | return err; | |
281 | } | |
282 | continue; | |
283 | } | |
284 | ||
285 | if (h->nlmsg_type == NLMSG_ERROR) { | |
286 | struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h); | |
287 | if (l < sizeof(struct nlmsgerr)) { | |
288 | fprintf(stderr, "ERROR truncated\n"); | |
289 | } else { | |
290 | errno = -err->error; | |
291 | if (errno == 0) { | |
292 | if (answer) | |
293 | memcpy(answer, h, h->nlmsg_len); | |
294 | return 0; | |
295 | } | |
296 | perror("RTNETLINK answers"); | |
297 | } | |
298 | return -1; | |
299 | } | |
300 | if (answer) { | |
301 | memcpy(answer, h, h->nlmsg_len); | |
302 | return 0; | |
303 | } | |
304 | ||
305 | fprintf(stderr, "Unexpected reply!!!\n"); | |
306 | ||
307 | status -= NLMSG_ALIGN(len); | |
308 | h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len)); | |
309 | } | |
310 | if (msg.msg_flags & MSG_TRUNC) { | |
311 | fprintf(stderr, "Message truncated\n"); | |
312 | continue; | |
313 | } | |
314 | if (status) { | |
315 | fprintf(stderr, "!!!Remnant of size %d\n", status); | |
316 | exit(1); | |
317 | } | |
318 | } | |
319 | } | |
320 | ||
321 | int rtnl_listen(struct rtnl_handle *rtnl, | |
322 | int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *), | |
323 | void *jarg) | |
324 | { | |
325 | int status; | |
326 | struct nlmsghdr *h; | |
327 | struct sockaddr_nl nladdr; | |
328 | struct iovec iov; | |
329 | char buf[8192]; | |
330 | struct msghdr msg = { | |
331 | (void*)&nladdr, sizeof(nladdr), | |
332 | &iov, 1, | |
333 | NULL, 0, | |
334 | 0 | |
335 | }; | |
336 | ||
337 | memset(&nladdr, 0, sizeof(nladdr)); | |
338 | nladdr.nl_family = AF_NETLINK; | |
339 | nladdr.nl_pid = 0; | |
340 | nladdr.nl_groups = 0; | |
341 | ||
342 | ||
343 | iov.iov_base = buf; | |
344 | ||
345 | while (1) { | |
346 | iov.iov_len = sizeof(buf); | |
347 | status = recvmsg(rtnl->fd, &msg, 0); | |
348 | ||
349 | if (status < 0) { | |
350 | if (errno == EINTR) | |
351 | continue; | |
352 | perror("OVERRUN"); | |
353 | continue; | |
354 | } | |
355 | if (status == 0) { | |
356 | fprintf(stderr, "EOF on netlink\n"); | |
357 | return -1; | |
358 | } | |
359 | if (msg.msg_namelen != sizeof(nladdr)) { | |
360 | fprintf(stderr, "Sender address length == %d\n", msg.msg_namelen); | |
361 | exit(1); | |
362 | } | |
363 | for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) { | |
364 | int err; | |
365 | int len = h->nlmsg_len; | |
366 | int l = len - sizeof(*h); | |
367 | ||
368 | if (l<0 || len>status) { | |
369 | if (msg.msg_flags & MSG_TRUNC) { | |
370 | fprintf(stderr, "Truncated message\n"); | |
371 | return -1; | |
372 | } | |
373 | fprintf(stderr, "!!!malformed message: len=%d\n", len); | |
374 | exit(1); | |
375 | } | |
376 | ||
377 | err = handler(&nladdr, h, jarg); | |
378 | if (err < 0) | |
379 | return err; | |
380 | ||
381 | status -= NLMSG_ALIGN(len); | |
382 | h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len)); | |
383 | } | |
384 | if (msg.msg_flags & MSG_TRUNC) { | |
385 | fprintf(stderr, "Message truncated\n"); | |
386 | continue; | |
387 | } | |
388 | if (status) { | |
389 | fprintf(stderr, "!!!Remnant of size %d\n", status); | |
390 | exit(1); | |
391 | } | |
392 | } | |
393 | } | |
394 | ||
395 | int rtnl_from_file(FILE *rtnl, | |
396 | int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *), | |
397 | void *jarg) | |
398 | { | |
399 | int status; | |
400 | struct sockaddr_nl nladdr; | |
401 | char buf[8192]; | |
402 | struct nlmsghdr *h = (void*)buf; | |
403 | ||
404 | memset(&nladdr, 0, sizeof(nladdr)); | |
405 | nladdr.nl_family = AF_NETLINK; | |
406 | nladdr.nl_pid = 0; | |
407 | nladdr.nl_groups = 0; | |
408 | ||
409 | while (1) { | |
410 | int err, len, type; | |
411 | int l; | |
412 | ||
413 | status = fread(&buf, 1, sizeof(*h), rtnl); | |
414 | ||
415 | if (status < 0) { | |
416 | if (errno == EINTR) | |
417 | continue; | |
418 | perror("rtnl_from_file: fread"); | |
419 | return -1; | |
420 | } | |
421 | if (status == 0) | |
422 | return 0; | |
423 | ||
424 | len = h->nlmsg_len; | |
425 | type= h->nlmsg_type; | |
426 | l = len - sizeof(*h); | |
427 | ||
428 | if (l<0 || len>sizeof(buf)) { | |
429 | fprintf(stderr, "!!!malformed message: len=%d @%lu\n", | |
430 | len, ftell(rtnl)); | |
431 | return -1; | |
432 | } | |
433 | ||
434 | status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl); | |
435 | ||
436 | if (status < 0) { | |
437 | perror("rtnl_from_file: fread"); | |
438 | return -1; | |
439 | } | |
440 | if (status < l) { | |
441 | fprintf(stderr, "rtnl-from_file: truncated message\n"); | |
442 | return -1; | |
443 | } | |
444 | ||
445 | err = handler(&nladdr, h, jarg); | |
446 | if (err < 0) | |
447 | return err; | |
448 | } | |
449 | } | |
450 | ||
451 | int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data) | |
452 | { | |
453 | int len = RTA_LENGTH(4); | |
454 | struct rtattr *rta; | |
455 | if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen) | |
456 | return -1; | |
457 | rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len)); | |
458 | rta->rta_type = type; | |
459 | rta->rta_len = len; | |
460 | memcpy(RTA_DATA(rta), &data, 4); | |
461 | n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len; | |
462 | return 0; | |
463 | } | |
464 | ||
465 | int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen) | |
466 | { | |
467 | int len = RTA_LENGTH(alen); | |
468 | struct rtattr *rta; | |
469 | ||
470 | if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen) | |
471 | return -1; | |
472 | rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len)); | |
473 | rta->rta_type = type; | |
474 | rta->rta_len = len; | |
475 | memcpy(RTA_DATA(rta), data, alen); | |
476 | n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len; | |
477 | return 0; | |
478 | } | |
479 | ||
480 | int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data) | |
481 | { | |
482 | int len = RTA_LENGTH(4); | |
483 | struct rtattr *subrta; | |
484 | ||
485 | if (RTA_ALIGN(rta->rta_len) + len > maxlen) | |
486 | return -1; | |
487 | subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len)); | |
488 | subrta->rta_type = type; | |
489 | subrta->rta_len = len; | |
490 | memcpy(RTA_DATA(subrta), &data, 4); | |
491 | rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len; | |
492 | return 0; | |
493 | } | |
494 | ||
495 | int rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen) | |
496 | { | |
497 | struct rtattr *subrta; | |
498 | int len = RTA_LENGTH(alen); | |
499 | ||
500 | if (RTA_ALIGN(rta->rta_len) + len > maxlen) | |
501 | return -1; | |
502 | subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len)); | |
503 | subrta->rta_type = type; | |
504 | subrta->rta_len = len; | |
505 | memcpy(RTA_DATA(subrta), data, alen); | |
506 | rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len; | |
507 | return 0; | |
508 | } | |
509 | ||
510 | ||
511 | int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len) | |
512 | { | |
513 | while (RTA_OK(rta, len)) { | |
514 | if (rta->rta_type <= max) | |
515 | tb[rta->rta_type] = rta; | |
516 | rta = RTA_NEXT(rta,len); | |
517 | } | |
518 | if (len) | |
519 | fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len); | |
520 | return 0; | |
521 | } |