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064af421 BP |
1 | /* |
2 | * Copyright (c) 2008, 2009 Nicira Networks. | |
3 | * | |
a14bc59f BP |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
064af421 | 7 | * |
a14bc59f BP |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
064af421 BP |
15 | */ |
16 | ||
17 | #include <config.h> | |
18 | #include "netlink.h" | |
19 | #include <assert.h> | |
20 | #include <errno.h> | |
21 | #include <inttypes.h> | |
22 | #include <stdio.h> | |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
25 | #include <time.h> | |
26 | #include <unistd.h> | |
27 | #include "coverage.h" | |
28 | #include "dynamic-string.h" | |
29 | #include "netlink-protocol.h" | |
30 | #include "ofpbuf.h" | |
31 | #include "poll-loop.h" | |
32 | #include "timeval.h" | |
33 | #include "util.h" | |
34 | ||
35 | #include "vlog.h" | |
36 | #define THIS_MODULE VLM_netlink | |
37 | ||
38 | /* Linux header file confusion causes this to be undefined. */ | |
39 | #ifndef SOL_NETLINK | |
40 | #define SOL_NETLINK 270 | |
41 | #endif | |
42 | ||
43 | /* A single (bad) Netlink message can in theory dump out many, many log | |
44 | * messages, so the burst size is set quite high here to avoid missing useful | |
45 | * information. Also, at high logging levels we log *all* Netlink messages. */ | |
46 | static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 600); | |
47 | ||
48 | static void log_nlmsg(const char *function, int error, | |
49 | const void *message, size_t size); | |
50 | \f | |
51 | /* Netlink sockets. */ | |
52 | ||
53 | struct nl_sock | |
54 | { | |
55 | int fd; | |
56 | uint32_t pid; | |
57 | }; | |
58 | ||
59 | /* Next nlmsghdr sequence number. | |
60 | * | |
61 | * This implementation uses sequence numbers that are unique process-wide, to | |
62 | * avoid a hypothetical race: send request, close socket, open new socket that | |
63 | * reuses the old socket's PID value, send request on new socket, receive reply | |
64 | * from kernel to old socket but with same PID and sequence number. (This race | |
65 | * could be avoided other ways, e.g. by preventing PIDs from being quickly | |
66 | * reused). */ | |
67 | static uint32_t next_seq; | |
68 | ||
69 | static int alloc_pid(uint32_t *); | |
70 | static void free_pid(uint32_t); | |
71 | ||
72 | /* Creates a new netlink socket for the given netlink 'protocol' | |
73 | * (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the | |
74 | * new socket if successful, otherwise returns a positive errno value. | |
75 | * | |
76 | * If 'multicast_group' is nonzero, the new socket subscribes to the specified | |
77 | * netlink multicast group. (A netlink socket may listen to an arbitrary | |
78 | * number of multicast groups, but so far we only need one at a time.) | |
79 | * | |
80 | * Nonzero 'so_sndbuf' or 'so_rcvbuf' override the kernel default send or | |
81 | * receive buffer size, respectively. | |
82 | */ | |
83 | int | |
84 | nl_sock_create(int protocol, int multicast_group, | |
85 | size_t so_sndbuf, size_t so_rcvbuf, struct nl_sock **sockp) | |
86 | { | |
87 | struct nl_sock *sock; | |
88 | struct sockaddr_nl local, remote; | |
89 | int retval = 0; | |
90 | ||
91 | if (next_seq == 0) { | |
92 | /* Pick initial sequence number. */ | |
93 | next_seq = getpid() ^ time_now(); | |
94 | } | |
95 | ||
96 | *sockp = NULL; | |
97 | sock = malloc(sizeof *sock); | |
98 | if (sock == NULL) { | |
99 | return ENOMEM; | |
100 | } | |
101 | ||
102 | sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol); | |
103 | if (sock->fd < 0) { | |
104 | VLOG_ERR("fcntl: %s", strerror(errno)); | |
105 | goto error; | |
106 | } | |
107 | ||
108 | retval = alloc_pid(&sock->pid); | |
109 | if (retval) { | |
110 | goto error; | |
111 | } | |
112 | ||
113 | if (so_sndbuf != 0 | |
114 | && setsockopt(sock->fd, SOL_SOCKET, SO_SNDBUF, | |
115 | &so_sndbuf, sizeof so_sndbuf) < 0) { | |
116 | VLOG_ERR("setsockopt(SO_SNDBUF,%zu): %s", so_sndbuf, strerror(errno)); | |
117 | goto error_free_pid; | |
118 | } | |
119 | ||
120 | if (so_rcvbuf != 0 | |
121 | && setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUF, | |
122 | &so_rcvbuf, sizeof so_rcvbuf) < 0) { | |
123 | VLOG_ERR("setsockopt(SO_RCVBUF,%zu): %s", so_rcvbuf, strerror(errno)); | |
124 | goto error_free_pid; | |
125 | } | |
126 | ||
127 | /* Bind local address as our selected pid. */ | |
128 | memset(&local, 0, sizeof local); | |
129 | local.nl_family = AF_NETLINK; | |
130 | local.nl_pid = sock->pid; | |
131 | if (multicast_group > 0 && multicast_group <= 32) { | |
132 | /* This method of joining multicast groups is supported by old kernels, | |
133 | * but it only allows 32 multicast groups per protocol. */ | |
134 | local.nl_groups |= 1ul << (multicast_group - 1); | |
135 | } | |
136 | if (bind(sock->fd, (struct sockaddr *) &local, sizeof local) < 0) { | |
137 | VLOG_ERR("bind(%"PRIu32"): %s", sock->pid, strerror(errno)); | |
138 | goto error_free_pid; | |
139 | } | |
140 | ||
141 | /* Bind remote address as the kernel (pid 0). */ | |
142 | memset(&remote, 0, sizeof remote); | |
143 | remote.nl_family = AF_NETLINK; | |
144 | remote.nl_pid = 0; | |
145 | if (connect(sock->fd, (struct sockaddr *) &remote, sizeof remote) < 0) { | |
146 | VLOG_ERR("connect(0): %s", strerror(errno)); | |
147 | goto error_free_pid; | |
148 | } | |
149 | ||
150 | /* Older kernel headers failed to define this macro. We want our programs | |
151 | * to support the newer kernel features even if compiled with older | |
152 | * headers, so define it ourselves in such a case. */ | |
153 | #ifndef NETLINK_ADD_MEMBERSHIP | |
154 | #define NETLINK_ADD_MEMBERSHIP 1 | |
155 | #endif | |
156 | ||
157 | /* This method of joining multicast groups is only supported by newish | |
158 | * kernels, but it allows for an arbitrary number of multicast groups. */ | |
159 | if (multicast_group > 32 | |
160 | && setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, | |
161 | &multicast_group, sizeof multicast_group) < 0) { | |
162 | VLOG_ERR("setsockopt(NETLINK_ADD_MEMBERSHIP,%d): %s", | |
163 | multicast_group, strerror(errno)); | |
164 | goto error_free_pid; | |
165 | } | |
166 | ||
167 | *sockp = sock; | |
168 | return 0; | |
169 | ||
170 | error_free_pid: | |
171 | free_pid(sock->pid); | |
172 | error: | |
173 | if (retval == 0) { | |
174 | retval = errno; | |
175 | if (retval == 0) { | |
176 | retval = EINVAL; | |
177 | } | |
178 | } | |
179 | if (sock->fd >= 0) { | |
180 | close(sock->fd); | |
181 | } | |
182 | free(sock); | |
183 | return retval; | |
184 | } | |
185 | ||
186 | /* Destroys netlink socket 'sock'. */ | |
187 | void | |
188 | nl_sock_destroy(struct nl_sock *sock) | |
189 | { | |
190 | if (sock) { | |
191 | close(sock->fd); | |
192 | free_pid(sock->pid); | |
193 | free(sock); | |
194 | } | |
195 | } | |
196 | ||
197 | /* Tries to send 'msg', which must contain a Netlink message, to the kernel on | |
198 | * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size before the | |
199 | * message is sent. | |
200 | * | |
201 | * Returns 0 if successful, otherwise a positive errno value. If | |
202 | * 'wait' is true, then the send will wait until buffer space is ready; | |
203 | * otherwise, returns EAGAIN if the 'sock' send buffer is full. */ | |
204 | int | |
205 | nl_sock_send(struct nl_sock *sock, const struct ofpbuf *msg, bool wait) | |
206 | { | |
207 | int error; | |
208 | ||
209 | nl_msg_nlmsghdr(msg)->nlmsg_len = msg->size; | |
210 | do { | |
211 | int retval; | |
212 | retval = send(sock->fd, msg->data, msg->size, wait ? 0 : MSG_DONTWAIT); | |
213 | error = retval < 0 ? errno : 0; | |
214 | } while (error == EINTR); | |
215 | log_nlmsg(__func__, error, msg->data, msg->size); | |
216 | if (!error) { | |
217 | COVERAGE_INC(netlink_sent); | |
218 | } | |
219 | return error; | |
220 | } | |
221 | ||
222 | /* Tries to send the 'n_iov' chunks of data in 'iov' to the kernel on 'sock' as | |
223 | * a single Netlink message. (The message must be fully formed and not require | |
224 | * finalization of its nlmsg_len field.) | |
225 | * | |
226 | * Returns 0 if successful, otherwise a positive errno value. If 'wait' is | |
227 | * true, then the send will wait until buffer space is ready; otherwise, | |
228 | * returns EAGAIN if the 'sock' send buffer is full. */ | |
229 | int | |
230 | nl_sock_sendv(struct nl_sock *sock, const struct iovec iov[], size_t n_iov, | |
231 | bool wait) | |
232 | { | |
233 | struct msghdr msg; | |
234 | int error; | |
235 | ||
236 | COVERAGE_INC(netlink_send); | |
237 | memset(&msg, 0, sizeof msg); | |
238 | msg.msg_iov = (struct iovec *) iov; | |
239 | msg.msg_iovlen = n_iov; | |
240 | do { | |
241 | int retval; | |
242 | retval = sendmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT); | |
243 | error = retval < 0 ? errno : 0; | |
244 | } while (error == EINTR); | |
245 | if (error != EAGAIN) { | |
246 | log_nlmsg(__func__, error, iov[0].iov_base, iov[0].iov_len); | |
247 | if (!error) { | |
248 | COVERAGE_INC(netlink_sent); | |
249 | } | |
250 | } | |
251 | return error; | |
252 | } | |
253 | ||
254 | /* Tries to receive a netlink message from the kernel on 'sock'. If | |
255 | * successful, stores the received message into '*bufp' and returns 0. The | |
256 | * caller is responsible for destroying the message with ofpbuf_delete(). On | |
257 | * failure, returns a positive errno value and stores a null pointer into | |
258 | * '*bufp'. | |
259 | * | |
260 | * If 'wait' is true, nl_sock_recv waits for a message to be ready; otherwise, | |
261 | * returns EAGAIN if the 'sock' receive buffer is empty. */ | |
262 | int | |
263 | nl_sock_recv(struct nl_sock *sock, struct ofpbuf **bufp, bool wait) | |
264 | { | |
265 | uint8_t tmp; | |
266 | ssize_t bufsize = 2048; | |
267 | ssize_t nbytes, nbytes2; | |
268 | struct ofpbuf *buf; | |
269 | struct nlmsghdr *nlmsghdr; | |
270 | struct iovec iov; | |
271 | struct msghdr msg = { | |
272 | .msg_name = NULL, | |
273 | .msg_namelen = 0, | |
274 | .msg_iov = &iov, | |
275 | .msg_iovlen = 1, | |
276 | .msg_control = NULL, | |
277 | .msg_controllen = 0, | |
278 | .msg_flags = 0 | |
279 | }; | |
280 | ||
281 | buf = ofpbuf_new(bufsize); | |
282 | *bufp = NULL; | |
283 | ||
284 | try_again: | |
285 | /* Attempt to read the message. We don't know the size of the data | |
286 | * yet, so we take a guess at 2048. If we're wrong, we keep trying | |
287 | * and doubling the buffer size each time. | |
288 | */ | |
289 | nlmsghdr = ofpbuf_put_uninit(buf, bufsize); | |
290 | iov.iov_base = nlmsghdr; | |
291 | iov.iov_len = bufsize; | |
292 | do { | |
293 | nbytes = recvmsg(sock->fd, &msg, (wait ? 0 : MSG_DONTWAIT) | MSG_PEEK); | |
294 | } while (nbytes < 0 && errno == EINTR); | |
295 | if (nbytes < 0) { | |
296 | ofpbuf_delete(buf); | |
297 | return errno; | |
298 | } | |
299 | if (msg.msg_flags & MSG_TRUNC) { | |
300 | COVERAGE_INC(netlink_recv_retry); | |
301 | bufsize *= 2; | |
302 | ofpbuf_reinit(buf, bufsize); | |
303 | goto try_again; | |
304 | } | |
305 | buf->size = nbytes; | |
306 | ||
307 | /* We successfully read the message, so recv again to clear the queue */ | |
308 | iov.iov_base = &tmp; | |
309 | iov.iov_len = 1; | |
310 | do { | |
311 | nbytes2 = recvmsg(sock->fd, &msg, MSG_DONTWAIT); | |
312 | } while (nbytes2 < 0 && errno == EINTR); | |
313 | if (nbytes2 < 0) { | |
314 | if (errno == ENOBUFS) { | |
315 | /* The kernel is notifying us that a message it tried to send to us | |
316 | * was dropped. We have to pass this along to the caller in case | |
317 | * it wants to retry a request. So kill the buffer, which we can | |
318 | * re-read next time. */ | |
319 | COVERAGE_INC(netlink_overflow); | |
320 | ofpbuf_delete(buf); | |
321 | return ENOBUFS; | |
322 | } else { | |
323 | VLOG_ERR_RL(&rl, "failed to remove nlmsg from socket: %s\n", | |
324 | strerror(errno)); | |
325 | } | |
326 | } | |
327 | if (nbytes < sizeof *nlmsghdr | |
328 | || nlmsghdr->nlmsg_len < sizeof *nlmsghdr | |
329 | || nlmsghdr->nlmsg_len > nbytes) { | |
330 | VLOG_ERR_RL(&rl, "received invalid nlmsg (%zd bytes < %d)", | |
331 | bufsize, NLMSG_HDRLEN); | |
332 | ofpbuf_delete(buf); | |
333 | return EPROTO; | |
334 | } | |
335 | *bufp = buf; | |
336 | log_nlmsg(__func__, 0, buf->data, buf->size); | |
337 | COVERAGE_INC(netlink_received); | |
338 | return 0; | |
339 | } | |
340 | ||
341 | /* Sends 'request' to the kernel via 'sock' and waits for a response. If | |
342 | * successful, stores the reply into '*replyp' and returns 0. The caller is | |
343 | * responsible for destroying the reply with ofpbuf_delete(). On failure, | |
344 | * returns a positive errno value and stores a null pointer into '*replyp'. | |
345 | * | |
346 | * The caller is responsible for destroying 'request'. | |
347 | * | |
348 | * Bare Netlink is an unreliable transport protocol. This function layers | |
349 | * reliable delivery and reply semantics on top of bare Netlink. | |
350 | * | |
351 | * In Netlink, sending a request to the kernel is reliable enough, because the | |
352 | * kernel will tell us if the message cannot be queued (and we will in that | |
353 | * case put it on the transmit queue and wait until it can be delivered). | |
354 | * | |
355 | * Receiving the reply is the real problem: if the socket buffer is full when | |
356 | * the kernel tries to send the reply, the reply will be dropped. However, the | |
357 | * kernel sets a flag that a reply has been dropped. The next call to recv | |
358 | * then returns ENOBUFS. We can then re-send the request. | |
359 | * | |
360 | * Caveats: | |
361 | * | |
362 | * 1. Netlink depends on sequence numbers to match up requests and | |
363 | * replies. The sender of a request supplies a sequence number, and | |
364 | * the reply echos back that sequence number. | |
365 | * | |
366 | * This is fine, but (1) some kernel netlink implementations are | |
367 | * broken, in that they fail to echo sequence numbers and (2) this | |
368 | * function will drop packets with non-matching sequence numbers, so | |
369 | * that only a single request can be usefully transacted at a time. | |
370 | * | |
371 | * 2. Resending the request causes it to be re-executed, so the request | |
372 | * needs to be idempotent. | |
373 | */ | |
374 | int | |
375 | nl_sock_transact(struct nl_sock *sock, | |
376 | const struct ofpbuf *request, struct ofpbuf **replyp) | |
377 | { | |
378 | uint32_t seq = nl_msg_nlmsghdr(request)->nlmsg_seq; | |
379 | struct nlmsghdr *nlmsghdr; | |
380 | struct ofpbuf *reply; | |
381 | int retval; | |
382 | ||
383 | *replyp = NULL; | |
384 | ||
385 | /* Ensure that we get a reply even if this message doesn't ordinarily call | |
386 | * for one. */ | |
387 | nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_ACK; | |
388 | ||
389 | send: | |
390 | retval = nl_sock_send(sock, request, true); | |
391 | if (retval) { | |
392 | return retval; | |
393 | } | |
394 | ||
395 | recv: | |
396 | retval = nl_sock_recv(sock, &reply, true); | |
397 | if (retval) { | |
398 | if (retval == ENOBUFS) { | |
399 | COVERAGE_INC(netlink_overflow); | |
400 | VLOG_DBG_RL(&rl, "receive buffer overflow, resending request"); | |
401 | goto send; | |
402 | } else { | |
403 | return retval; | |
404 | } | |
405 | } | |
406 | nlmsghdr = nl_msg_nlmsghdr(reply); | |
407 | if (seq != nlmsghdr->nlmsg_seq) { | |
408 | VLOG_DBG_RL(&rl, "ignoring seq %"PRIu32" != expected %"PRIu32, | |
409 | nl_msg_nlmsghdr(reply)->nlmsg_seq, seq); | |
410 | ofpbuf_delete(reply); | |
411 | goto recv; | |
412 | } | |
413 | if (nl_msg_nlmsgerr(reply, &retval)) { | |
414 | ofpbuf_delete(reply); | |
415 | if (retval) { | |
416 | VLOG_DBG_RL(&rl, "received NAK error=%d (%s)", | |
417 | retval, strerror(retval)); | |
418 | } | |
419 | return retval != EAGAIN ? retval : EPROTO; | |
420 | } | |
421 | ||
422 | *replyp = reply; | |
423 | return 0; | |
424 | } | |
425 | ||
426 | /* Causes poll_block() to wake up when any of the specified 'events' (which is | |
427 | * a OR'd combination of POLLIN, POLLOUT, etc.) occur on 'sock'. */ | |
428 | void | |
429 | nl_sock_wait(const struct nl_sock *sock, short int events) | |
430 | { | |
431 | poll_fd_wait(sock->fd, events); | |
432 | } | |
433 | \f | |
434 | /* Netlink messages. */ | |
435 | ||
436 | /* Returns the nlmsghdr at the head of 'msg'. | |
437 | * | |
438 | * 'msg' must be at least as large as a nlmsghdr. */ | |
439 | struct nlmsghdr * | |
440 | nl_msg_nlmsghdr(const struct ofpbuf *msg) | |
441 | { | |
442 | return ofpbuf_at_assert(msg, 0, NLMSG_HDRLEN); | |
443 | } | |
444 | ||
445 | /* Returns the genlmsghdr just past 'msg''s nlmsghdr. | |
446 | * | |
447 | * Returns a null pointer if 'msg' is not large enough to contain an nlmsghdr | |
448 | * and a genlmsghdr. */ | |
449 | struct genlmsghdr * | |
450 | nl_msg_genlmsghdr(const struct ofpbuf *msg) | |
451 | { | |
452 | return ofpbuf_at(msg, NLMSG_HDRLEN, GENL_HDRLEN); | |
453 | } | |
454 | ||
455 | /* If 'buffer' is a NLMSG_ERROR message, stores 0 in '*errorp' if it is an ACK | |
456 | * message, otherwise a positive errno value, and returns true. If 'buffer' is | |
457 | * not an NLMSG_ERROR message, returns false. | |
458 | * | |
459 | * 'msg' must be at least as large as a nlmsghdr. */ | |
460 | bool | |
461 | nl_msg_nlmsgerr(const struct ofpbuf *msg, int *errorp) | |
462 | { | |
463 | if (nl_msg_nlmsghdr(msg)->nlmsg_type == NLMSG_ERROR) { | |
464 | struct nlmsgerr *err = ofpbuf_at(msg, NLMSG_HDRLEN, sizeof *err); | |
465 | int code = EPROTO; | |
466 | if (!err) { | |
467 | VLOG_ERR_RL(&rl, "received invalid nlmsgerr (%zd bytes < %zd)", | |
468 | msg->size, NLMSG_HDRLEN + sizeof *err); | |
469 | } else if (err->error <= 0 && err->error > INT_MIN) { | |
470 | code = -err->error; | |
471 | } | |
472 | if (errorp) { | |
473 | *errorp = code; | |
474 | } | |
475 | return true; | |
476 | } else { | |
477 | return false; | |
478 | } | |
479 | } | |
480 | ||
481 | /* Ensures that 'b' has room for at least 'size' bytes plus netlink padding at | |
482 | * its tail end, reallocating and copying its data if necessary. */ | |
483 | void | |
484 | nl_msg_reserve(struct ofpbuf *msg, size_t size) | |
485 | { | |
486 | ofpbuf_prealloc_tailroom(msg, NLMSG_ALIGN(size)); | |
487 | } | |
488 | ||
489 | /* Puts a nlmsghdr at the beginning of 'msg', which must be initially empty. | |
490 | * Uses the given 'type' and 'flags'. 'sock' is used to obtain a PID and | |
491 | * sequence number for proper routing of replies. 'expected_payload' should be | |
492 | * an estimate of the number of payload bytes to be supplied; if the size of | |
493 | * the payload is unknown a value of 0 is acceptable. | |
494 | * | |
495 | * 'type' is ordinarily an enumerated value specific to the Netlink protocol | |
496 | * (e.g. RTM_NEWLINK, for NETLINK_ROUTE protocol). For Generic Netlink, 'type' | |
497 | * is the family number obtained via nl_lookup_genl_family(). | |
498 | * | |
499 | * 'flags' is a bit-mask that indicates what kind of request is being made. It | |
500 | * is often NLM_F_REQUEST indicating that a request is being made, commonly | |
501 | * or'd with NLM_F_ACK to request an acknowledgement. | |
502 | * | |
503 | * nl_msg_put_genlmsghdr is more convenient for composing a Generic Netlink | |
504 | * message. */ | |
505 | void | |
506 | nl_msg_put_nlmsghdr(struct ofpbuf *msg, struct nl_sock *sock, | |
507 | size_t expected_payload, uint32_t type, uint32_t flags) | |
508 | { | |
509 | struct nlmsghdr *nlmsghdr; | |
510 | ||
511 | assert(msg->size == 0); | |
512 | ||
513 | nl_msg_reserve(msg, NLMSG_HDRLEN + expected_payload); | |
514 | nlmsghdr = nl_msg_put_uninit(msg, NLMSG_HDRLEN); | |
515 | nlmsghdr->nlmsg_len = 0; | |
516 | nlmsghdr->nlmsg_type = type; | |
517 | nlmsghdr->nlmsg_flags = flags; | |
518 | nlmsghdr->nlmsg_seq = ++next_seq; | |
519 | nlmsghdr->nlmsg_pid = sock->pid; | |
520 | } | |
521 | ||
522 | /* Puts a nlmsghdr and genlmsghdr at the beginning of 'msg', which must be | |
523 | * initially empty. 'sock' is used to obtain a PID and sequence number for | |
524 | * proper routing of replies. 'expected_payload' should be an estimate of the | |
525 | * number of payload bytes to be supplied; if the size of the payload is | |
526 | * unknown a value of 0 is acceptable. | |
527 | * | |
528 | * 'family' is the family number obtained via nl_lookup_genl_family(). | |
529 | * | |
530 | * 'flags' is a bit-mask that indicates what kind of request is being made. It | |
531 | * is often NLM_F_REQUEST indicating that a request is being made, commonly | |
532 | * or'd with NLM_F_ACK to request an acknowledgement. | |
533 | * | |
534 | * 'cmd' is an enumerated value specific to the Generic Netlink family | |
535 | * (e.g. CTRL_CMD_NEWFAMILY for the GENL_ID_CTRL family). | |
536 | * | |
537 | * 'version' is a version number specific to the family and command (often 1). | |
538 | * | |
539 | * nl_msg_put_nlmsghdr should be used to compose Netlink messages that are not | |
540 | * Generic Netlink messages. */ | |
541 | void | |
542 | nl_msg_put_genlmsghdr(struct ofpbuf *msg, struct nl_sock *sock, | |
543 | size_t expected_payload, int family, uint32_t flags, | |
544 | uint8_t cmd, uint8_t version) | |
545 | { | |
546 | struct genlmsghdr *genlmsghdr; | |
547 | ||
548 | nl_msg_put_nlmsghdr(msg, sock, GENL_HDRLEN + expected_payload, | |
549 | family, flags); | |
550 | assert(msg->size == NLMSG_HDRLEN); | |
551 | genlmsghdr = nl_msg_put_uninit(msg, GENL_HDRLEN); | |
552 | genlmsghdr->cmd = cmd; | |
553 | genlmsghdr->version = version; | |
554 | genlmsghdr->reserved = 0; | |
555 | } | |
556 | ||
557 | /* Appends the 'size' bytes of data in 'p', plus Netlink padding if needed, to | |
558 | * the tail end of 'msg'. Data in 'msg' is reallocated and copied if | |
559 | * necessary. */ | |
560 | void | |
561 | nl_msg_put(struct ofpbuf *msg, const void *data, size_t size) | |
562 | { | |
563 | memcpy(nl_msg_put_uninit(msg, size), data, size); | |
564 | } | |
565 | ||
566 | /* Appends 'size' bytes of data, plus Netlink padding if needed, to the tail | |
567 | * end of 'msg', reallocating and copying its data if necessary. Returns a | |
568 | * pointer to the first byte of the new data, which is left uninitialized. */ | |
569 | void * | |
570 | nl_msg_put_uninit(struct ofpbuf *msg, size_t size) | |
571 | { | |
572 | size_t pad = NLMSG_ALIGN(size) - size; | |
573 | char *p = ofpbuf_put_uninit(msg, size + pad); | |
574 | if (pad) { | |
575 | memset(p + size, 0, pad); | |
576 | } | |
577 | return p; | |
578 | } | |
579 | ||
580 | /* Appends a Netlink attribute of the given 'type' and room for 'size' bytes of | |
581 | * data as its payload, plus Netlink padding if needed, to the tail end of | |
582 | * 'msg', reallocating and copying its data if necessary. Returns a pointer to | |
583 | * the first byte of data in the attribute, which is left uninitialized. */ | |
584 | void * | |
585 | nl_msg_put_unspec_uninit(struct ofpbuf *msg, uint16_t type, size_t size) | |
586 | { | |
587 | size_t total_size = NLA_HDRLEN + size; | |
588 | struct nlattr* nla = nl_msg_put_uninit(msg, total_size); | |
589 | assert(NLA_ALIGN(total_size) <= UINT16_MAX); | |
590 | nla->nla_len = total_size; | |
591 | nla->nla_type = type; | |
592 | return nla + 1; | |
593 | } | |
594 | ||
595 | /* Appends a Netlink attribute of the given 'type' and the 'size' bytes of | |
596 | * 'data' as its payload, to the tail end of 'msg', reallocating and copying | |
597 | * its data if necessary. Returns a pointer to the first byte of data in the | |
598 | * attribute, which is left uninitialized. */ | |
599 | void | |
600 | nl_msg_put_unspec(struct ofpbuf *msg, uint16_t type, | |
601 | const void *data, size_t size) | |
602 | { | |
603 | memcpy(nl_msg_put_unspec_uninit(msg, type, size), data, size); | |
604 | } | |
605 | ||
606 | /* Appends a Netlink attribute of the given 'type' and no payload to 'msg'. | |
607 | * (Some Netlink protocols use the presence or absence of an attribute as a | |
608 | * Boolean flag.) */ | |
609 | void | |
610 | nl_msg_put_flag(struct ofpbuf *msg, uint16_t type) | |
611 | { | |
612 | nl_msg_put_unspec(msg, type, NULL, 0); | |
613 | } | |
614 | ||
615 | /* Appends a Netlink attribute of the given 'type' and the given 8-bit 'value' | |
616 | * to 'msg'. */ | |
617 | void | |
618 | nl_msg_put_u8(struct ofpbuf *msg, uint16_t type, uint8_t value) | |
619 | { | |
620 | nl_msg_put_unspec(msg, type, &value, sizeof value); | |
621 | } | |
622 | ||
623 | /* Appends a Netlink attribute of the given 'type' and the given 16-bit 'value' | |
624 | * to 'msg'. */ | |
625 | void | |
626 | nl_msg_put_u16(struct ofpbuf *msg, uint16_t type, uint16_t value) | |
627 | { | |
628 | nl_msg_put_unspec(msg, type, &value, sizeof value); | |
629 | } | |
630 | ||
631 | /* Appends a Netlink attribute of the given 'type' and the given 32-bit 'value' | |
632 | * to 'msg'. */ | |
633 | void | |
634 | nl_msg_put_u32(struct ofpbuf *msg, uint16_t type, uint32_t value) | |
635 | { | |
636 | nl_msg_put_unspec(msg, type, &value, sizeof value); | |
637 | } | |
638 | ||
639 | /* Appends a Netlink attribute of the given 'type' and the given 64-bit 'value' | |
640 | * to 'msg'. */ | |
641 | void | |
642 | nl_msg_put_u64(struct ofpbuf *msg, uint16_t type, uint64_t value) | |
643 | { | |
644 | nl_msg_put_unspec(msg, type, &value, sizeof value); | |
645 | } | |
646 | ||
647 | /* Appends a Netlink attribute of the given 'type' and the given | |
648 | * null-terminated string 'value' to 'msg'. */ | |
649 | void | |
650 | nl_msg_put_string(struct ofpbuf *msg, uint16_t type, const char *value) | |
651 | { | |
652 | nl_msg_put_unspec(msg, type, value, strlen(value) + 1); | |
653 | } | |
654 | ||
655 | /* Appends a Netlink attribute of the given 'type' and the given buffered | |
656 | * netlink message in 'nested_msg' to 'msg'. The nlmsg_len field in | |
657 | * 'nested_msg' is finalized to match 'nested_msg->size'. */ | |
658 | void | |
659 | nl_msg_put_nested(struct ofpbuf *msg, | |
660 | uint16_t type, struct ofpbuf *nested_msg) | |
661 | { | |
662 | nl_msg_nlmsghdr(nested_msg)->nlmsg_len = nested_msg->size; | |
663 | nl_msg_put_unspec(msg, type, nested_msg->data, nested_msg->size); | |
664 | } | |
665 | ||
666 | /* Returns the first byte in the payload of attribute 'nla'. */ | |
667 | const void * | |
668 | nl_attr_get(const struct nlattr *nla) | |
669 | { | |
670 | assert(nla->nla_len >= NLA_HDRLEN); | |
671 | return nla + 1; | |
672 | } | |
673 | ||
674 | /* Returns the number of bytes in the payload of attribute 'nla'. */ | |
675 | size_t | |
676 | nl_attr_get_size(const struct nlattr *nla) | |
677 | { | |
678 | assert(nla->nla_len >= NLA_HDRLEN); | |
679 | return nla->nla_len - NLA_HDRLEN; | |
680 | } | |
681 | ||
682 | /* Asserts that 'nla''s payload is at least 'size' bytes long, and returns the | |
683 | * first byte of the payload. */ | |
684 | const void * | |
685 | nl_attr_get_unspec(const struct nlattr *nla, size_t size) | |
686 | { | |
687 | assert(nla->nla_len >= NLA_HDRLEN + size); | |
688 | return nla + 1; | |
689 | } | |
690 | ||
691 | /* Returns true if 'nla' is nonnull. (Some Netlink protocols use the presence | |
692 | * or absence of an attribute as a Boolean flag.) */ | |
693 | bool | |
694 | nl_attr_get_flag(const struct nlattr *nla) | |
695 | { | |
696 | return nla != NULL; | |
697 | } | |
698 | ||
699 | #define NL_ATTR_GET_AS(NLA, TYPE) \ | |
700 | (*(TYPE*) nl_attr_get_unspec(nla, sizeof(TYPE))) | |
701 | ||
702 | /* Returns the 8-bit value in 'nla''s payload. | |
703 | * | |
704 | * Asserts that 'nla''s payload is at least 1 byte long. */ | |
705 | uint8_t | |
706 | nl_attr_get_u8(const struct nlattr *nla) | |
707 | { | |
708 | return NL_ATTR_GET_AS(nla, uint8_t); | |
709 | } | |
710 | ||
711 | /* Returns the 16-bit value in 'nla''s payload. | |
712 | * | |
713 | * Asserts that 'nla''s payload is at least 2 bytes long. */ | |
714 | uint16_t | |
715 | nl_attr_get_u16(const struct nlattr *nla) | |
716 | { | |
717 | return NL_ATTR_GET_AS(nla, uint16_t); | |
718 | } | |
719 | ||
720 | /* Returns the 32-bit value in 'nla''s payload. | |
721 | * | |
722 | * Asserts that 'nla''s payload is at least 4 bytes long. */ | |
723 | uint32_t | |
724 | nl_attr_get_u32(const struct nlattr *nla) | |
725 | { | |
726 | return NL_ATTR_GET_AS(nla, uint32_t); | |
727 | } | |
728 | ||
729 | /* Returns the 64-bit value in 'nla''s payload. | |
730 | * | |
731 | * Asserts that 'nla''s payload is at least 8 bytes long. */ | |
732 | uint64_t | |
733 | nl_attr_get_u64(const struct nlattr *nla) | |
734 | { | |
735 | return NL_ATTR_GET_AS(nla, uint64_t); | |
736 | } | |
737 | ||
738 | /* Returns the null-terminated string value in 'nla''s payload. | |
739 | * | |
740 | * Asserts that 'nla''s payload contains a null-terminated string. */ | |
741 | const char * | |
742 | nl_attr_get_string(const struct nlattr *nla) | |
743 | { | |
744 | assert(nla->nla_len > NLA_HDRLEN); | |
745 | assert(memchr(nl_attr_get(nla), '\0', nla->nla_len - NLA_HDRLEN) != NULL); | |
746 | return nl_attr_get(nla); | |
747 | } | |
748 | ||
749 | /* Default minimum and maximum payload sizes for each type of attribute. */ | |
750 | static const size_t attr_len_range[][2] = { | |
751 | [0 ... N_NL_ATTR_TYPES - 1] = { 0, SIZE_MAX }, | |
752 | [NL_A_U8] = { 1, 1 }, | |
753 | [NL_A_U16] = { 2, 2 }, | |
754 | [NL_A_U32] = { 4, 4 }, | |
755 | [NL_A_U64] = { 8, 8 }, | |
756 | [NL_A_STRING] = { 1, SIZE_MAX }, | |
757 | [NL_A_FLAG] = { 0, SIZE_MAX }, | |
758 | [NL_A_NESTED] = { NLMSG_HDRLEN, SIZE_MAX }, | |
759 | }; | |
760 | ||
761 | /* Parses the 'msg' starting at the given 'nla_offset' as a sequence of Netlink | |
762 | * attributes. 'policy[i]', for 0 <= i < n_attrs, specifies how the attribute | |
763 | * with nla_type == i is parsed; a pointer to attribute i is stored in | |
764 | * attrs[i]. Returns true if successful, false on failure. | |
765 | * | |
766 | * If the Netlink attributes in 'msg' follow a Netlink header and a Generic | |
767 | * Netlink header, then 'nla_offset' should be NLMSG_HDRLEN + GENL_HDRLEN. */ | |
768 | bool | |
769 | nl_policy_parse(const struct ofpbuf *msg, size_t nla_offset, | |
770 | const struct nl_policy policy[], | |
771 | struct nlattr *attrs[], size_t n_attrs) | |
772 | { | |
773 | void *p, *tail; | |
774 | size_t n_required; | |
775 | size_t i; | |
776 | ||
777 | n_required = 0; | |
778 | for (i = 0; i < n_attrs; i++) { | |
779 | attrs[i] = NULL; | |
780 | ||
781 | assert(policy[i].type < N_NL_ATTR_TYPES); | |
782 | if (policy[i].type != NL_A_NO_ATTR | |
783 | && policy[i].type != NL_A_FLAG | |
784 | && !policy[i].optional) { | |
785 | n_required++; | |
786 | } | |
787 | } | |
788 | ||
789 | p = ofpbuf_at(msg, nla_offset, 0); | |
790 | if (p == NULL) { | |
791 | VLOG_DBG_RL(&rl, "missing headers in nl_policy_parse"); | |
792 | return false; | |
793 | } | |
794 | tail = ofpbuf_tail(msg); | |
795 | ||
796 | while (p < tail) { | |
797 | size_t offset = (char*)p - (char*)msg->data; | |
798 | struct nlattr *nla = p; | |
799 | size_t len, aligned_len; | |
800 | uint16_t type; | |
801 | ||
802 | /* Make sure its claimed length is plausible. */ | |
803 | if (nla->nla_len < NLA_HDRLEN) { | |
804 | VLOG_DBG_RL(&rl, "%zu: attr shorter than NLA_HDRLEN (%"PRIu16")", | |
805 | offset, nla->nla_len); | |
806 | return false; | |
807 | } | |
808 | len = nla->nla_len - NLA_HDRLEN; | |
809 | aligned_len = NLA_ALIGN(len); | |
810 | if (aligned_len > (char*)tail - (char*)p) { | |
811 | VLOG_DBG_RL(&rl, "%zu: attr %"PRIu16" aligned data len (%zu) " | |
812 | "> bytes left (%tu)", | |
813 | offset, nla->nla_type, aligned_len, | |
814 | (char*)tail - (char*)p); | |
815 | return false; | |
816 | } | |
817 | ||
818 | type = nla->nla_type; | |
819 | if (type < n_attrs && policy[type].type != NL_A_NO_ATTR) { | |
820 | const struct nl_policy *p = &policy[type]; | |
821 | size_t min_len, max_len; | |
822 | ||
823 | /* Validate length and content. */ | |
824 | min_len = p->min_len ? p->min_len : attr_len_range[p->type][0]; | |
825 | max_len = p->max_len ? p->max_len : attr_len_range[p->type][1]; | |
826 | if (len < min_len || len > max_len) { | |
827 | VLOG_DBG_RL(&rl, "%zu: attr %"PRIu16" length %zu not in " | |
828 | "allowed range %zu...%zu", | |
829 | offset, type, len, min_len, max_len); | |
830 | return false; | |
831 | } | |
832 | if (p->type == NL_A_STRING) { | |
833 | if (((char *) nla)[nla->nla_len - 1]) { | |
834 | VLOG_DBG_RL(&rl, "%zu: attr %"PRIu16" lacks null at end", | |
835 | offset, type); | |
836 | return false; | |
837 | } | |
838 | if (memchr(nla + 1, '\0', len - 1) != NULL) { | |
839 | VLOG_DBG_RL(&rl, "%zu: attr %"PRIu16" has bad length", | |
840 | offset, type); | |
841 | return false; | |
842 | } | |
843 | } | |
844 | if (!p->optional && attrs[type] == NULL) { | |
845 | assert(n_required > 0); | |
846 | --n_required; | |
847 | } | |
848 | attrs[type] = nla; | |
849 | } else { | |
850 | /* Skip attribute type that we don't care about. */ | |
851 | } | |
852 | p = (char*)p + NLA_ALIGN(nla->nla_len); | |
853 | } | |
854 | if (n_required) { | |
855 | VLOG_DBG_RL(&rl, "%zu required attrs missing", n_required); | |
856 | return false; | |
857 | } | |
858 | return true; | |
859 | } | |
860 | \f | |
861 | /* Miscellaneous. */ | |
862 | ||
863 | static const struct nl_policy family_policy[CTRL_ATTR_MAX + 1] = { | |
864 | [CTRL_ATTR_FAMILY_ID] = {.type = NL_A_U16}, | |
865 | }; | |
866 | ||
867 | static int do_lookup_genl_family(const char *name) | |
868 | { | |
869 | struct nl_sock *sock; | |
870 | struct ofpbuf request, *reply; | |
871 | struct nlattr *attrs[ARRAY_SIZE(family_policy)]; | |
872 | int retval; | |
873 | ||
874 | retval = nl_sock_create(NETLINK_GENERIC, 0, 0, 0, &sock); | |
875 | if (retval) { | |
876 | return -retval; | |
877 | } | |
878 | ||
879 | ofpbuf_init(&request, 0); | |
880 | nl_msg_put_genlmsghdr(&request, sock, 0, GENL_ID_CTRL, NLM_F_REQUEST, | |
881 | CTRL_CMD_GETFAMILY, 1); | |
882 | nl_msg_put_string(&request, CTRL_ATTR_FAMILY_NAME, name); | |
883 | retval = nl_sock_transact(sock, &request, &reply); | |
884 | ofpbuf_uninit(&request); | |
885 | if (retval) { | |
886 | nl_sock_destroy(sock); | |
887 | return -retval; | |
888 | } | |
889 | ||
890 | if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN, | |
891 | family_policy, attrs, ARRAY_SIZE(family_policy))) { | |
892 | nl_sock_destroy(sock); | |
893 | ofpbuf_delete(reply); | |
894 | return -EPROTO; | |
895 | } | |
896 | ||
897 | retval = nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]); | |
898 | if (retval == 0) { | |
899 | retval = -EPROTO; | |
900 | } | |
901 | nl_sock_destroy(sock); | |
902 | ofpbuf_delete(reply); | |
903 | return retval; | |
904 | } | |
905 | ||
906 | /* If '*number' is 0, translates the given Generic Netlink family 'name' to a | |
907 | * number and stores it in '*number'. If successful, returns 0 and the caller | |
908 | * may use '*number' as the family number. On failure, returns a positive | |
909 | * errno value and '*number' caches the errno value. */ | |
910 | int | |
911 | nl_lookup_genl_family(const char *name, int *number) | |
912 | { | |
913 | if (*number == 0) { | |
914 | *number = do_lookup_genl_family(name); | |
915 | assert(*number != 0); | |
916 | } | |
917 | return *number > 0 ? 0 : -*number; | |
918 | } | |
919 | \f | |
920 | /* Netlink PID. | |
921 | * | |
922 | * Every Netlink socket must be bound to a unique 32-bit PID. By convention, | |
923 | * programs that have a single Netlink socket use their Unix process ID as PID, | |
924 | * and programs with multiple Netlink sockets add a unique per-socket | |
925 | * identifier in the bits above the Unix process ID. | |
926 | * | |
927 | * The kernel has Netlink PID 0. | |
928 | */ | |
929 | ||
930 | /* Parameters for how many bits in the PID should come from the Unix process ID | |
931 | * and how many unique per-socket. */ | |
932 | #define SOCKET_BITS 10 | |
933 | #define MAX_SOCKETS (1u << SOCKET_BITS) | |
934 | ||
935 | #define PROCESS_BITS (32 - SOCKET_BITS) | |
936 | #define MAX_PROCESSES (1u << PROCESS_BITS) | |
937 | #define PROCESS_MASK ((uint32_t) (MAX_PROCESSES - 1)) | |
938 | ||
939 | /* Bit vector of unused socket identifiers. */ | |
940 | static uint32_t avail_sockets[ROUND_UP(MAX_SOCKETS, 32)]; | |
941 | ||
942 | /* Allocates and returns a new Netlink PID. */ | |
943 | static int | |
944 | alloc_pid(uint32_t *pid) | |
945 | { | |
946 | int i; | |
947 | ||
948 | for (i = 0; i < MAX_SOCKETS; i++) { | |
949 | if ((avail_sockets[i / 32] & (1u << (i % 32))) == 0) { | |
950 | avail_sockets[i / 32] |= 1u << (i % 32); | |
951 | *pid = (getpid() & PROCESS_MASK) | (i << PROCESS_BITS); | |
952 | return 0; | |
953 | } | |
954 | } | |
955 | VLOG_ERR("netlink pid space exhausted"); | |
956 | return ENOBUFS; | |
957 | } | |
958 | ||
959 | /* Makes the specified 'pid' available for reuse. */ | |
960 | static void | |
961 | free_pid(uint32_t pid) | |
962 | { | |
963 | int sock = pid >> PROCESS_BITS; | |
964 | assert(avail_sockets[sock / 32] & (1u << (sock % 32))); | |
965 | avail_sockets[sock / 32] &= ~(1u << (sock % 32)); | |
966 | } | |
967 | \f | |
968 | static void | |
969 | nlmsghdr_to_string(const struct nlmsghdr *h, struct ds *ds) | |
970 | { | |
971 | struct nlmsg_flag { | |
972 | unsigned int bits; | |
973 | const char *name; | |
974 | }; | |
975 | static const struct nlmsg_flag flags[] = { | |
976 | { NLM_F_REQUEST, "REQUEST" }, | |
977 | { NLM_F_MULTI, "MULTI" }, | |
978 | { NLM_F_ACK, "ACK" }, | |
979 | { NLM_F_ECHO, "ECHO" }, | |
980 | { NLM_F_DUMP, "DUMP" }, | |
981 | { NLM_F_ROOT, "ROOT" }, | |
982 | { NLM_F_MATCH, "MATCH" }, | |
983 | { NLM_F_ATOMIC, "ATOMIC" }, | |
984 | }; | |
985 | const struct nlmsg_flag *flag; | |
986 | uint16_t flags_left; | |
987 | ||
988 | ds_put_format(ds, "nl(len:%"PRIu32", type=%"PRIu16, | |
989 | h->nlmsg_len, h->nlmsg_type); | |
990 | if (h->nlmsg_type == NLMSG_NOOP) { | |
991 | ds_put_cstr(ds, "(no-op)"); | |
992 | } else if (h->nlmsg_type == NLMSG_ERROR) { | |
993 | ds_put_cstr(ds, "(error)"); | |
994 | } else if (h->nlmsg_type == NLMSG_DONE) { | |
995 | ds_put_cstr(ds, "(done)"); | |
996 | } else if (h->nlmsg_type == NLMSG_OVERRUN) { | |
997 | ds_put_cstr(ds, "(overrun)"); | |
998 | } else if (h->nlmsg_type < NLMSG_MIN_TYPE) { | |
999 | ds_put_cstr(ds, "(reserved)"); | |
1000 | } else { | |
1001 | ds_put_cstr(ds, "(family-defined)"); | |
1002 | } | |
1003 | ds_put_format(ds, ", flags=%"PRIx16, h->nlmsg_flags); | |
1004 | flags_left = h->nlmsg_flags; | |
1005 | for (flag = flags; flag < &flags[ARRAY_SIZE(flags)]; flag++) { | |
1006 | if ((flags_left & flag->bits) == flag->bits) { | |
1007 | ds_put_format(ds, "[%s]", flag->name); | |
1008 | flags_left &= ~flag->bits; | |
1009 | } | |
1010 | } | |
1011 | if (flags_left) { | |
1012 | ds_put_format(ds, "[OTHER:%"PRIx16"]", flags_left); | |
1013 | } | |
1014 | ds_put_format(ds, ", seq=%"PRIx32", pid=%"PRIu32"(%d:%d))", | |
1015 | h->nlmsg_seq, h->nlmsg_pid, | |
1016 | (int) (h->nlmsg_pid & PROCESS_MASK), | |
1017 | (int) (h->nlmsg_pid >> PROCESS_BITS)); | |
1018 | } | |
1019 | ||
1020 | static char * | |
1021 | nlmsg_to_string(const struct ofpbuf *buffer) | |
1022 | { | |
1023 | struct ds ds = DS_EMPTY_INITIALIZER; | |
1024 | const struct nlmsghdr *h = ofpbuf_at(buffer, 0, NLMSG_HDRLEN); | |
1025 | if (h) { | |
1026 | nlmsghdr_to_string(h, &ds); | |
1027 | if (h->nlmsg_type == NLMSG_ERROR) { | |
1028 | const struct nlmsgerr *e; | |
1029 | e = ofpbuf_at(buffer, NLMSG_HDRLEN, | |
1030 | NLMSG_ALIGN(sizeof(struct nlmsgerr))); | |
1031 | if (e) { | |
1032 | ds_put_format(&ds, " error(%d", e->error); | |
1033 | if (e->error < 0) { | |
1034 | ds_put_format(&ds, "(%s)", strerror(-e->error)); | |
1035 | } | |
1036 | ds_put_cstr(&ds, ", in-reply-to("); | |
1037 | nlmsghdr_to_string(&e->msg, &ds); | |
1038 | ds_put_cstr(&ds, "))"); | |
1039 | } else { | |
1040 | ds_put_cstr(&ds, " error(truncated)"); | |
1041 | } | |
1042 | } else if (h->nlmsg_type == NLMSG_DONE) { | |
1043 | int *error = ofpbuf_at(buffer, NLMSG_HDRLEN, sizeof *error); | |
1044 | if (error) { | |
1045 | ds_put_format(&ds, " done(%d", *error); | |
1046 | if (*error < 0) { | |
1047 | ds_put_format(&ds, "(%s)", strerror(-*error)); | |
1048 | } | |
1049 | ds_put_cstr(&ds, ")"); | |
1050 | } else { | |
1051 | ds_put_cstr(&ds, " done(truncated)"); | |
1052 | } | |
1053 | } | |
1054 | } else { | |
1055 | ds_put_cstr(&ds, "nl(truncated)"); | |
1056 | } | |
1057 | return ds.string; | |
1058 | } | |
1059 | ||
1060 | static void | |
1061 | log_nlmsg(const char *function, int error, | |
1062 | const void *message, size_t size) | |
1063 | { | |
1064 | struct ofpbuf buffer; | |
1065 | char *nlmsg; | |
1066 | ||
1067 | if (!VLOG_IS_DBG_ENABLED()) { | |
1068 | return; | |
1069 | } | |
1070 | ||
1071 | buffer.data = (void *) message; | |
1072 | buffer.size = size; | |
1073 | nlmsg = nlmsg_to_string(&buffer); | |
1074 | VLOG_DBG_RL(&rl, "%s (%s): %s", function, strerror(error), nlmsg); | |
1075 | free(nlmsg); | |
1076 | } | |
1077 |