2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
18 #include "netlink-socket.h"
22 #include <sys/types.h>
26 #include "dynamic-string.h"
30 #include "netlink-protocol.h"
32 #include "ovs-thread.h"
33 #include "poll-loop.h"
34 #include "socket-util.h"
38 VLOG_DEFINE_THIS_MODULE(netlink_socket
);
40 COVERAGE_DEFINE(netlink_overflow
);
41 COVERAGE_DEFINE(netlink_received
);
42 COVERAGE_DEFINE(netlink_recv_jumbo
);
43 COVERAGE_DEFINE(netlink_sent
);
45 /* Linux header file confusion causes this to be undefined. */
47 #define SOL_NETLINK 270
50 /* A single (bad) Netlink message can in theory dump out many, many log
51 * messages, so the burst size is set quite high here to avoid missing useful
52 * information. Also, at high logging levels we log *all* Netlink messages. */
53 static struct vlog_rate_limit rl
= VLOG_RATE_LIMIT_INIT(60, 600);
55 static uint32_t nl_sock_allocate_seq(struct nl_sock
*, unsigned int n
);
56 static void log_nlmsg(const char *function
, int error
,
57 const void *message
, size_t size
, int protocol
);
59 /* Netlink sockets. */
66 unsigned int rcvbuf
; /* Receive buffer size (SO_RCVBUF). */
69 /* Compile-time limit on iovecs, so that we can allocate a maximum-size array
70 * of iovecs on the stack. */
73 /* Maximum number of iovecs that may be passed to sendmsg, capped at a
74 * minimum of _XOPEN_IOV_MAX (16) and a maximum of MAX_IOVS.
76 * Initialized by nl_sock_create(). */
79 static int nl_pool_alloc(int protocol
, struct nl_sock
**sockp
);
80 static void nl_pool_release(struct nl_sock
*);
82 /* Creates a new netlink socket for the given netlink 'protocol'
83 * (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the
84 * new socket if successful, otherwise returns a positive errno value. */
86 nl_sock_create(int protocol
, struct nl_sock
**sockp
)
88 static struct ovsthread_once once
= OVSTHREAD_ONCE_INITIALIZER
;
90 struct sockaddr_nl local
, remote
;
95 if (ovsthread_once_start(&once
)) {
96 int save_errno
= errno
;
99 max_iovs
= sysconf(_SC_UIO_MAXIOV
);
100 if (max_iovs
< _XOPEN_IOV_MAX
) {
101 if (max_iovs
== -1 && errno
) {
102 VLOG_WARN("sysconf(_SC_UIO_MAXIOV): %s", ovs_strerror(errno
));
104 max_iovs
= _XOPEN_IOV_MAX
;
105 } else if (max_iovs
> MAX_IOVS
) {
110 ovsthread_once_done(&once
);
114 sock
= xmalloc(sizeof *sock
);
116 sock
->fd
= socket(AF_NETLINK
, SOCK_RAW
, protocol
);
118 VLOG_ERR("fcntl: %s", ovs_strerror(errno
));
121 sock
->protocol
= protocol
;
124 rcvbuf
= 1024 * 1024;
125 if (setsockopt(sock
->fd
, SOL_SOCKET
, SO_RCVBUFFORCE
,
126 &rcvbuf
, sizeof rcvbuf
)) {
127 /* Only root can use SO_RCVBUFFORCE. Everyone else gets EPERM.
128 * Warn only if the failure is therefore unexpected. */
129 if (errno
!= EPERM
) {
130 VLOG_WARN_RL(&rl
, "setting %d-byte socket receive buffer failed "
131 "(%s)", rcvbuf
, ovs_strerror(errno
));
135 retval
= get_socket_rcvbuf(sock
->fd
);
140 sock
->rcvbuf
= retval
;
142 /* Connect to kernel (pid 0) as remote address. */
143 memset(&remote
, 0, sizeof remote
);
144 remote
.nl_family
= AF_NETLINK
;
146 if (connect(sock
->fd
, (struct sockaddr
*) &remote
, sizeof remote
) < 0) {
147 VLOG_ERR("connect(0): %s", ovs_strerror(errno
));
151 /* Obtain pid assigned by kernel. */
152 local_size
= sizeof local
;
153 if (getsockname(sock
->fd
, (struct sockaddr
*) &local
, &local_size
) < 0) {
154 VLOG_ERR("getsockname: %s", ovs_strerror(errno
));
157 if (local_size
< sizeof local
|| local
.nl_family
!= AF_NETLINK
) {
158 VLOG_ERR("getsockname returned bad Netlink name");
162 sock
->pid
= local
.nl_pid
;
181 /* Creates a new netlink socket for the same protocol as 'src'. Returns 0 and
182 * sets '*sockp' to the new socket if successful, otherwise returns a positive
185 nl_sock_clone(const struct nl_sock
*src
, struct nl_sock
**sockp
)
187 return nl_sock_create(src
->protocol
, sockp
);
190 /* Destroys netlink socket 'sock'. */
192 nl_sock_destroy(struct nl_sock
*sock
)
200 /* Tries to add 'sock' as a listener for 'multicast_group'. Returns 0 if
201 * successful, otherwise a positive errno value.
203 * A socket that is subscribed to a multicast group that receives asynchronous
204 * notifications must not be used for Netlink transactions or dumps, because
205 * transactions and dumps can cause notifications to be lost.
207 * Multicast group numbers are always positive.
209 * It is not an error to attempt to join a multicast group to which a socket
210 * already belongs. */
212 nl_sock_join_mcgroup(struct nl_sock
*sock
, unsigned int multicast_group
)
214 if (setsockopt(sock
->fd
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
,
215 &multicast_group
, sizeof multicast_group
) < 0) {
216 VLOG_WARN("could not join multicast group %u (%s)",
217 multicast_group
, ovs_strerror(errno
));
223 /* Tries to make 'sock' stop listening to 'multicast_group'. Returns 0 if
224 * successful, otherwise a positive errno value.
226 * Multicast group numbers are always positive.
228 * It is not an error to attempt to leave a multicast group to which a socket
231 * On success, reading from 'sock' will still return any messages that were
232 * received on 'multicast_group' before the group was left. */
234 nl_sock_leave_mcgroup(struct nl_sock
*sock
, unsigned int multicast_group
)
236 if (setsockopt(sock
->fd
, SOL_NETLINK
, NETLINK_DROP_MEMBERSHIP
,
237 &multicast_group
, sizeof multicast_group
) < 0) {
238 VLOG_WARN("could not leave multicast group %u (%s)",
239 multicast_group
, ovs_strerror(errno
));
246 nl_sock_send__(struct nl_sock
*sock
, const struct ofpbuf
*msg
,
247 uint32_t nlmsg_seq
, bool wait
)
249 struct nlmsghdr
*nlmsg
= nl_msg_nlmsghdr(msg
);
252 nlmsg
->nlmsg_len
= msg
->size
;
253 nlmsg
->nlmsg_seq
= nlmsg_seq
;
254 nlmsg
->nlmsg_pid
= sock
->pid
;
257 retval
= send(sock
->fd
, msg
->data
, msg
->size
, wait
? 0 : MSG_DONTWAIT
);
258 error
= retval
< 0 ? errno
: 0;
259 } while (error
== EINTR
);
260 log_nlmsg(__func__
, error
, msg
->data
, msg
->size
, sock
->protocol
);
262 COVERAGE_INC(netlink_sent
);
267 /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
268 * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
269 * will be set to 'sock''s pid, and nlmsg_seq will be initialized to a fresh
270 * sequence number, before the message is sent.
272 * Returns 0 if successful, otherwise a positive errno value. If
273 * 'wait' is true, then the send will wait until buffer space is ready;
274 * otherwise, returns EAGAIN if the 'sock' send buffer is full. */
276 nl_sock_send(struct nl_sock
*sock
, const struct ofpbuf
*msg
, bool wait
)
278 return nl_sock_send_seq(sock
, msg
, nl_sock_allocate_seq(sock
, 1), wait
);
281 /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
282 * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
283 * will be set to 'sock''s pid, and nlmsg_seq will be initialized to
284 * 'nlmsg_seq', before the message is sent.
286 * Returns 0 if successful, otherwise a positive errno value. If
287 * 'wait' is true, then the send will wait until buffer space is ready;
288 * otherwise, returns EAGAIN if the 'sock' send buffer is full.
290 * This function is suitable for sending a reply to a request that was received
291 * with sequence number 'nlmsg_seq'. Otherwise, use nl_sock_send() instead. */
293 nl_sock_send_seq(struct nl_sock
*sock
, const struct ofpbuf
*msg
,
294 uint32_t nlmsg_seq
, bool wait
)
296 return nl_sock_send__(sock
, msg
, nlmsg_seq
, wait
);
300 nl_sock_recv__(struct nl_sock
*sock
, struct ofpbuf
*buf
, bool wait
)
302 /* We can't accurately predict the size of the data to be received. The
303 * caller is supposed to have allocated enough space in 'buf' to handle the
304 * "typical" case. To handle exceptions, we make available enough space in
305 * 'tail' to allow Netlink messages to be up to 64 kB long (a reasonable
306 * figure since that's the maximum length of a Netlink attribute). */
307 struct nlmsghdr
*nlmsghdr
;
313 ovs_assert(buf
->allocated
>= sizeof *nlmsghdr
);
316 iov
[0].iov_base
= buf
->base
;
317 iov
[0].iov_len
= buf
->allocated
;
318 iov
[1].iov_base
= tail
;
319 iov
[1].iov_len
= sizeof tail
;
321 memset(&msg
, 0, sizeof msg
);
326 retval
= recvmsg(sock
->fd
, &msg
, wait
? 0 : MSG_DONTWAIT
);
327 } while (retval
< 0 && errno
== EINTR
);
331 if (error
== ENOBUFS
) {
332 /* Socket receive buffer overflow dropped one or more messages that
333 * the kernel tried to send to us. */
334 COVERAGE_INC(netlink_overflow
);
339 if (msg
.msg_flags
& MSG_TRUNC
) {
340 VLOG_ERR_RL(&rl
, "truncated message (longer than %"PRIuSIZE
" bytes)",
345 nlmsghdr
= buf
->data
;
346 if (retval
< sizeof *nlmsghdr
347 || nlmsghdr
->nlmsg_len
< sizeof *nlmsghdr
348 || nlmsghdr
->nlmsg_len
> retval
) {
349 VLOG_ERR_RL(&rl
, "received invalid nlmsg (%"PRIuSIZE
"d bytes < %"PRIuSIZE
")",
350 retval
, sizeof *nlmsghdr
);
354 buf
->size
= MIN(retval
, buf
->allocated
);
355 if (retval
> buf
->allocated
) {
356 COVERAGE_INC(netlink_recv_jumbo
);
357 ofpbuf_put(buf
, tail
, retval
- buf
->allocated
);
360 log_nlmsg(__func__
, 0, buf
->data
, buf
->size
, sock
->protocol
);
361 COVERAGE_INC(netlink_received
);
366 /* Tries to receive a Netlink message from the kernel on 'sock' into 'buf'. If
367 * 'wait' is true, waits for a message to be ready. Otherwise, fails with
368 * EAGAIN if the 'sock' receive buffer is empty.
370 * The caller must have initialized 'buf' with an allocation of at least
371 * NLMSG_HDRLEN bytes. For best performance, the caller should allocate enough
372 * space for a "typical" message.
374 * On success, returns 0 and replaces 'buf''s previous content by the received
375 * message. This function expands 'buf''s allocated memory, as necessary, to
376 * hold the actual size of the received message.
378 * On failure, returns a positive errno value and clears 'buf' to zero length.
379 * 'buf' retains its previous memory allocation.
381 * Regardless of success or failure, this function resets 'buf''s headroom to
384 nl_sock_recv(struct nl_sock
*sock
, struct ofpbuf
*buf
, bool wait
)
386 return nl_sock_recv__(sock
, buf
, wait
);
390 nl_sock_record_errors__(struct nl_transaction
**transactions
, size_t n
,
395 for (i
= 0; i
< n
; i
++) {
396 struct nl_transaction
*txn
= transactions
[i
];
400 ofpbuf_clear(txn
->reply
);
406 nl_sock_transact_multiple__(struct nl_sock
*sock
,
407 struct nl_transaction
**transactions
, size_t n
,
410 uint64_t tmp_reply_stub
[1024 / 8];
411 struct nl_transaction tmp_txn
;
412 struct ofpbuf tmp_reply
;
415 struct iovec iovs
[MAX_IOVS
];
420 base_seq
= nl_sock_allocate_seq(sock
, n
);
422 for (i
= 0; i
< n
; i
++) {
423 struct nl_transaction
*txn
= transactions
[i
];
424 struct nlmsghdr
*nlmsg
= nl_msg_nlmsghdr(txn
->request
);
426 nlmsg
->nlmsg_len
= txn
->request
->size
;
427 nlmsg
->nlmsg_seq
= base_seq
+ i
;
428 nlmsg
->nlmsg_pid
= sock
->pid
;
430 iovs
[i
].iov_base
= txn
->request
->data
;
431 iovs
[i
].iov_len
= txn
->request
->size
;
434 memset(&msg
, 0, sizeof msg
);
438 error
= sendmsg(sock
->fd
, &msg
, 0) < 0 ? errno
: 0;
439 } while (error
== EINTR
);
441 for (i
= 0; i
< n
; i
++) {
442 struct nl_transaction
*txn
= transactions
[i
];
444 log_nlmsg(__func__
, error
, txn
->request
->data
, txn
->request
->size
,
448 COVERAGE_ADD(netlink_sent
, n
);
455 ofpbuf_use_stub(&tmp_reply
, tmp_reply_stub
, sizeof tmp_reply_stub
);
456 tmp_txn
.request
= NULL
;
457 tmp_txn
.reply
= &tmp_reply
;
460 struct nl_transaction
*buf_txn
, *txn
;
463 /* Find a transaction whose buffer we can use for receiving a reply.
464 * If no such transaction is left, use tmp_txn. */
466 for (i
= 0; i
< n
; i
++) {
467 if (transactions
[i
]->reply
) {
468 buf_txn
= transactions
[i
];
473 /* Receive a reply. */
474 error
= nl_sock_recv__(sock
, buf_txn
->reply
, false);
476 if (error
== EAGAIN
) {
477 nl_sock_record_errors__(transactions
, n
, 0);
484 /* Match the reply up with a transaction. */
485 seq
= nl_msg_nlmsghdr(buf_txn
->reply
)->nlmsg_seq
;
486 if (seq
< base_seq
|| seq
>= base_seq
+ n
) {
487 VLOG_DBG_RL(&rl
, "ignoring unexpected seq %#"PRIx32
, seq
);
491 txn
= transactions
[i
];
493 /* Fill in the results for 'txn'. */
494 if (nl_msg_nlmsgerr(buf_txn
->reply
, &txn
->error
)) {
496 ofpbuf_clear(txn
->reply
);
499 VLOG_DBG_RL(&rl
, "received NAK error=%d (%s)",
500 error
, ovs_strerror(txn
->error
));
504 if (txn
->reply
&& txn
!= buf_txn
) {
506 struct ofpbuf
*reply
= buf_txn
->reply
;
507 buf_txn
->reply
= txn
->reply
;
512 /* Fill in the results for transactions before 'txn'. (We have to do
513 * this after the results for 'txn' itself because of the buffer swap
515 nl_sock_record_errors__(transactions
, i
, 0);
519 transactions
+= i
+ 1;
523 ofpbuf_uninit(&tmp_reply
);
528 /* Sends the 'request' member of the 'n' transactions in 'transactions' on
529 * 'sock', in order, and receives responses to all of them. Fills in the
530 * 'error' member of each transaction with 0 if it was successful, otherwise
531 * with a positive errno value. If 'reply' is nonnull, then it will be filled
532 * with the reply if the message receives a detailed reply. In other cases,
533 * i.e. where the request failed or had no reply beyond an indication of
534 * success, 'reply' will be cleared if it is nonnull.
536 * The caller is responsible for destroying each request and reply, and the
537 * transactions array itself.
539 * Before sending each message, this function will finalize nlmsg_len in each
540 * 'request' to match the ofpbuf's size, set nlmsg_pid to 'sock''s pid, and
541 * initialize nlmsg_seq.
543 * Bare Netlink is an unreliable transport protocol. This function layers
544 * reliable delivery and reply semantics on top of bare Netlink. See
545 * nl_sock_transact() for some caveats.
548 nl_sock_transact_multiple(struct nl_sock
*sock
,
549 struct nl_transaction
**transactions
, size_t n
)
558 /* In theory, every request could have a 64 kB reply. But the default and
559 * maximum socket rcvbuf size with typical Dom0 memory sizes both tend to
560 * be a bit below 128 kB, so that would only allow a single message in a
561 * "batch". So we assume that replies average (at most) 4 kB, which allows
562 * a good deal of batching.
564 * In practice, most of the requests that we batch either have no reply at
565 * all or a brief reply. */
566 max_batch_count
= MAX(sock
->rcvbuf
/ 4096, 1);
567 max_batch_count
= MIN(max_batch_count
, max_iovs
);
573 /* Batch up to 'max_batch_count' transactions. But cap it at about a
574 * page of requests total because big skbuffs are expensive to
575 * allocate in the kernel. */
576 #if defined(PAGESIZE)
577 enum { MAX_BATCH_BYTES
= MAX(1, PAGESIZE
- 512) };
579 enum { MAX_BATCH_BYTES
= 4096 - 512 };
581 bytes
= transactions
[0]->request
->size
;
582 for (count
= 1; count
< n
&& count
< max_batch_count
; count
++) {
583 if (bytes
+ transactions
[count
]->request
->size
> MAX_BATCH_BYTES
) {
586 bytes
+= transactions
[count
]->request
->size
;
589 error
= nl_sock_transact_multiple__(sock
, transactions
, count
, &done
);
590 transactions
+= done
;
593 if (error
== ENOBUFS
) {
594 VLOG_DBG_RL(&rl
, "receive buffer overflow, resending request");
596 VLOG_ERR_RL(&rl
, "transaction error (%s)", ovs_strerror(error
));
597 nl_sock_record_errors__(transactions
, n
, error
);
602 /* Sends 'request' to the kernel via 'sock' and waits for a response. If
603 * successful, returns 0. On failure, returns a positive errno value.
605 * If 'replyp' is nonnull, then on success '*replyp' is set to the kernel's
606 * reply, which the caller is responsible for freeing with ofpbuf_delete(), and
607 * on failure '*replyp' is set to NULL. If 'replyp' is null, then the kernel's
608 * reply, if any, is discarded.
610 * Before the message is sent, nlmsg_len in 'request' will be finalized to
611 * match msg->size, nlmsg_pid will be set to 'sock''s pid, and nlmsg_seq will
612 * be initialized, NLM_F_ACK will be set in nlmsg_flags.
614 * The caller is responsible for destroying 'request'.
616 * Bare Netlink is an unreliable transport protocol. This function layers
617 * reliable delivery and reply semantics on top of bare Netlink.
619 * In Netlink, sending a request to the kernel is reliable enough, because the
620 * kernel will tell us if the message cannot be queued (and we will in that
621 * case put it on the transmit queue and wait until it can be delivered).
623 * Receiving the reply is the real problem: if the socket buffer is full when
624 * the kernel tries to send the reply, the reply will be dropped. However, the
625 * kernel sets a flag that a reply has been dropped. The next call to recv
626 * then returns ENOBUFS. We can then re-send the request.
630 * 1. Netlink depends on sequence numbers to match up requests and
631 * replies. The sender of a request supplies a sequence number, and
632 * the reply echos back that sequence number.
634 * This is fine, but (1) some kernel netlink implementations are
635 * broken, in that they fail to echo sequence numbers and (2) this
636 * function will drop packets with non-matching sequence numbers, so
637 * that only a single request can be usefully transacted at a time.
639 * 2. Resending the request causes it to be re-executed, so the request
640 * needs to be idempotent.
643 nl_sock_transact(struct nl_sock
*sock
, const struct ofpbuf
*request
,
644 struct ofpbuf
**replyp
)
646 struct nl_transaction
*transactionp
;
647 struct nl_transaction transaction
;
649 transaction
.request
= CONST_CAST(struct ofpbuf
*, request
);
650 transaction
.reply
= replyp
? ofpbuf_new(1024) : NULL
;
651 transactionp
= &transaction
;
653 nl_sock_transact_multiple(sock
, &transactionp
, 1);
656 if (transaction
.error
) {
657 ofpbuf_delete(transaction
.reply
);
660 *replyp
= transaction
.reply
;
664 return transaction
.error
;
667 /* Drain all the messages currently in 'sock''s receive queue. */
669 nl_sock_drain(struct nl_sock
*sock
)
671 return drain_rcvbuf(sock
->fd
);
674 /* Starts a Netlink "dump" operation, by sending 'request' to the kernel on a
675 * Netlink socket created with the given 'protocol', and initializes 'dump' to
676 * reflect the state of the operation.
678 * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will
679 * be set to the Netlink socket's pid, before the message is sent. NLM_F_DUMP
680 * and NLM_F_ACK will be set in nlmsg_flags.
682 * The design of this Netlink socket library ensures that the dump is reliable.
684 * This function provides no status indication. An error status for the entire
685 * dump operation is provided when it is completed by calling nl_dump_done().
687 * The caller is responsible for destroying 'request'.
690 nl_dump_start(struct nl_dump
*dump
, int protocol
, const struct ofpbuf
*request
)
692 ofpbuf_init(&dump
->buffer
, 4096);
693 dump
->status
= nl_pool_alloc(protocol
, &dump
->sock
);
698 nl_msg_nlmsghdr(request
)->nlmsg_flags
|= NLM_F_DUMP
| NLM_F_ACK
;
699 dump
->status
= nl_sock_send__(dump
->sock
, request
,
700 nl_sock_allocate_seq(dump
->sock
, 1), true);
701 dump
->seq
= nl_msg_nlmsghdr(request
)->nlmsg_seq
;
704 /* Helper function for nl_dump_next(). */
706 nl_dump_recv(struct nl_dump
*dump
)
708 struct nlmsghdr
*nlmsghdr
;
711 retval
= nl_sock_recv__(dump
->sock
, &dump
->buffer
, true);
713 return retval
== EINTR
? EAGAIN
: retval
;
716 nlmsghdr
= nl_msg_nlmsghdr(&dump
->buffer
);
717 if (dump
->seq
!= nlmsghdr
->nlmsg_seq
) {
718 VLOG_DBG_RL(&rl
, "ignoring seq %#"PRIx32
" != expected %#"PRIx32
,
719 nlmsghdr
->nlmsg_seq
, dump
->seq
);
723 if (nl_msg_nlmsgerr(&dump
->buffer
, &retval
)) {
724 VLOG_INFO_RL(&rl
, "netlink dump request error (%s)",
725 ovs_strerror(retval
));
726 return retval
&& retval
!= EAGAIN
? retval
: EPROTO
;
732 /* Attempts to retrieve another reply from 'dump', which must have been
733 * initialized with nl_dump_start().
735 * If successful, returns true and points 'reply->data' and 'reply->size' to
736 * the message that was retrieved. The caller must not modify 'reply' (because
737 * it points into the middle of a larger buffer).
739 * On failure, returns false and sets 'reply->data' to NULL and 'reply->size'
740 * to 0. Failure might indicate an actual error or merely the end of replies.
741 * An error status for the entire dump operation is provided when it is
742 * completed by calling nl_dump_done().
745 nl_dump_next(struct nl_dump
*dump
, struct ofpbuf
*reply
)
747 struct nlmsghdr
*nlmsghdr
;
755 while (!dump
->buffer
.size
) {
756 int retval
= nl_dump_recv(dump
);
758 ofpbuf_clear(&dump
->buffer
);
759 if (retval
!= EAGAIN
) {
760 dump
->status
= retval
;
766 nlmsghdr
= nl_msg_next(&dump
->buffer
, reply
);
768 VLOG_WARN_RL(&rl
, "netlink dump reply contains message fragment");
769 dump
->status
= EPROTO
;
771 } else if (nlmsghdr
->nlmsg_type
== NLMSG_DONE
) {
779 /* Completes Netlink dump operation 'dump', which must have been initialized
780 * with nl_dump_start(). Returns 0 if the dump operation was error-free,
781 * otherwise a positive errno value describing the problem. */
783 nl_dump_done(struct nl_dump
*dump
)
785 /* Drain any remaining messages that the client didn't read. Otherwise the
786 * kernel will continue to queue them up and waste buffer space.
788 * XXX We could just destroy and discard the socket in this case. */
789 while (!dump
->status
) {
791 if (!nl_dump_next(dump
, &reply
)) {
792 ovs_assert(dump
->status
);
795 nl_pool_release(dump
->sock
);
796 ofpbuf_uninit(&dump
->buffer
);
797 return dump
->status
== EOF
? 0 : dump
->status
;
800 /* Causes poll_block() to wake up when any of the specified 'events' (which is
801 * a OR'd combination of POLLIN, POLLOUT, etc.) occur on 'sock'. */
803 nl_sock_wait(const struct nl_sock
*sock
, short int events
)
805 poll_fd_wait(sock
->fd
, events
);
808 /* Returns the underlying fd for 'sock', for use in "poll()"-like operations
809 * that can't use nl_sock_wait().
811 * It's a little tricky to use the returned fd correctly, because nl_sock does
812 * "copy on write" to allow a single nl_sock to be used for notifications,
813 * transactions, and dumps. If 'sock' is used only for notifications and
814 * transactions (and never for dump) then the usage is safe. */
816 nl_sock_fd(const struct nl_sock
*sock
)
821 /* Returns the PID associated with this socket. */
823 nl_sock_pid(const struct nl_sock
*sock
)
831 struct hmap_node hmap_node
;
836 static struct hmap genl_families
= HMAP_INITIALIZER(&genl_families
);
838 static const struct nl_policy family_policy
[CTRL_ATTR_MAX
+ 1] = {
839 [CTRL_ATTR_FAMILY_ID
] = {.type
= NL_A_U16
},
840 [CTRL_ATTR_MCAST_GROUPS
] = {.type
= NL_A_NESTED
, .optional
= true},
843 static struct genl_family
*
844 find_genl_family_by_id(uint16_t id
)
846 struct genl_family
*family
;
848 HMAP_FOR_EACH_IN_BUCKET (family
, hmap_node
, hash_int(id
, 0),
850 if (family
->id
== id
) {
858 define_genl_family(uint16_t id
, const char *name
)
860 struct genl_family
*family
= find_genl_family_by_id(id
);
863 if (!strcmp(family
->name
, name
)) {
868 family
= xmalloc(sizeof *family
);
870 hmap_insert(&genl_families
, &family
->hmap_node
, hash_int(id
, 0));
872 family
->name
= xstrdup(name
);
876 genl_family_to_name(uint16_t id
)
878 if (id
== GENL_ID_CTRL
) {
881 struct genl_family
*family
= find_genl_family_by_id(id
);
882 return family
? family
->name
: "unknown";
887 do_lookup_genl_family(const char *name
, struct nlattr
**attrs
,
888 struct ofpbuf
**replyp
)
890 struct nl_sock
*sock
;
891 struct ofpbuf request
, *reply
;
895 error
= nl_sock_create(NETLINK_GENERIC
, &sock
);
900 ofpbuf_init(&request
, 0);
901 nl_msg_put_genlmsghdr(&request
, 0, GENL_ID_CTRL
, NLM_F_REQUEST
,
902 CTRL_CMD_GETFAMILY
, 1);
903 nl_msg_put_string(&request
, CTRL_ATTR_FAMILY_NAME
, name
);
904 error
= nl_sock_transact(sock
, &request
, &reply
);
905 ofpbuf_uninit(&request
);
907 nl_sock_destroy(sock
);
911 if (!nl_policy_parse(reply
, NLMSG_HDRLEN
+ GENL_HDRLEN
,
912 family_policy
, attrs
, ARRAY_SIZE(family_policy
))
913 || nl_attr_get_u16(attrs
[CTRL_ATTR_FAMILY_ID
]) == 0) {
914 nl_sock_destroy(sock
);
915 ofpbuf_delete(reply
);
919 nl_sock_destroy(sock
);
924 /* Finds the multicast group called 'group_name' in genl family 'family_name'.
925 * When successful, writes its result to 'multicast_group' and returns 0.
926 * Otherwise, clears 'multicast_group' and returns a positive error code.
929 nl_lookup_genl_mcgroup(const char *family_name
, const char *group_name
,
930 unsigned int *multicast_group
)
932 struct nlattr
*family_attrs
[ARRAY_SIZE(family_policy
)];
933 const struct nlattr
*mc
;
934 struct ofpbuf
*reply
;
938 *multicast_group
= 0;
939 error
= do_lookup_genl_family(family_name
, family_attrs
, &reply
);
944 if (!family_attrs
[CTRL_ATTR_MCAST_GROUPS
]) {
949 NL_NESTED_FOR_EACH (mc
, left
, family_attrs
[CTRL_ATTR_MCAST_GROUPS
]) {
950 static const struct nl_policy mc_policy
[] = {
951 [CTRL_ATTR_MCAST_GRP_ID
] = {.type
= NL_A_U32
},
952 [CTRL_ATTR_MCAST_GRP_NAME
] = {.type
= NL_A_STRING
},
955 struct nlattr
*mc_attrs
[ARRAY_SIZE(mc_policy
)];
958 if (!nl_parse_nested(mc
, mc_policy
, mc_attrs
, ARRAY_SIZE(mc_policy
))) {
963 mc_name
= nl_attr_get_string(mc_attrs
[CTRL_ATTR_MCAST_GRP_NAME
]);
964 if (!strcmp(group_name
, mc_name
)) {
966 nl_attr_get_u32(mc_attrs
[CTRL_ATTR_MCAST_GRP_ID
]);
974 ofpbuf_delete(reply
);
978 /* If '*number' is 0, translates the given Generic Netlink family 'name' to a
979 * number and stores it in '*number'. If successful, returns 0 and the caller
980 * may use '*number' as the family number. On failure, returns a positive
981 * errno value and '*number' caches the errno value. */
983 nl_lookup_genl_family(const char *name
, int *number
)
986 struct nlattr
*attrs
[ARRAY_SIZE(family_policy
)];
987 struct ofpbuf
*reply
;
990 error
= do_lookup_genl_family(name
, attrs
, &reply
);
992 *number
= nl_attr_get_u16(attrs
[CTRL_ATTR_FAMILY_ID
]);
993 define_genl_family(*number
, name
);
997 ofpbuf_delete(reply
);
999 ovs_assert(*number
!= 0);
1001 return *number
> 0 ? 0 : -*number
;
1005 struct nl_sock
*socks
[16];
1009 static struct ovs_mutex pool_mutex
= OVS_MUTEX_INITIALIZER
;
1010 static struct nl_pool pools
[MAX_LINKS
] OVS_GUARDED_BY(pool_mutex
);
1013 nl_pool_alloc(int protocol
, struct nl_sock
**sockp
)
1015 struct nl_sock
*sock
= NULL
;
1016 struct nl_pool
*pool
;
1018 ovs_assert(protocol
>= 0 && protocol
< ARRAY_SIZE(pools
));
1020 ovs_mutex_lock(&pool_mutex
);
1021 pool
= &pools
[protocol
];
1023 sock
= pool
->socks
[--pool
->n
];
1025 ovs_mutex_unlock(&pool_mutex
);
1031 return nl_sock_create(protocol
, sockp
);
1036 nl_pool_release(struct nl_sock
*sock
)
1039 struct nl_pool
*pool
= &pools
[sock
->protocol
];
1041 ovs_mutex_lock(&pool_mutex
);
1042 if (pool
->n
< ARRAY_SIZE(pool
->socks
)) {
1043 pool
->socks
[pool
->n
++] = sock
;
1046 ovs_mutex_unlock(&pool_mutex
);
1048 nl_sock_destroy(sock
);
1053 nl_transact(int protocol
, const struct ofpbuf
*request
,
1054 struct ofpbuf
**replyp
)
1056 struct nl_sock
*sock
;
1059 error
= nl_pool_alloc(protocol
, &sock
);
1065 error
= nl_sock_transact(sock
, request
, replyp
);
1067 nl_pool_release(sock
);
1072 nl_transact_multiple(int protocol
,
1073 struct nl_transaction
**transactions
, size_t n
)
1075 struct nl_sock
*sock
;
1078 error
= nl_pool_alloc(protocol
, &sock
);
1080 nl_sock_transact_multiple(sock
, transactions
, n
);
1081 nl_pool_release(sock
);
1083 nl_sock_record_errors__(transactions
, n
, error
);
1089 nl_sock_allocate_seq(struct nl_sock
*sock
, unsigned int n
)
1091 uint32_t seq
= sock
->next_seq
;
1093 sock
->next_seq
+= n
;
1095 /* Make it impossible for the next request for sequence numbers to wrap
1096 * around to 0. Start over with 1 to avoid ever using a sequence number of
1097 * 0, because the kernel uses sequence number 0 for notifications. */
1098 if (sock
->next_seq
>= UINT32_MAX
/ 2) {
1106 nlmsghdr_to_string(const struct nlmsghdr
*h
, int protocol
, struct ds
*ds
)
1112 static const struct nlmsg_flag flags
[] = {
1113 { NLM_F_REQUEST
, "REQUEST" },
1114 { NLM_F_MULTI
, "MULTI" },
1115 { NLM_F_ACK
, "ACK" },
1116 { NLM_F_ECHO
, "ECHO" },
1117 { NLM_F_DUMP
, "DUMP" },
1118 { NLM_F_ROOT
, "ROOT" },
1119 { NLM_F_MATCH
, "MATCH" },
1120 { NLM_F_ATOMIC
, "ATOMIC" },
1122 const struct nlmsg_flag
*flag
;
1123 uint16_t flags_left
;
1125 ds_put_format(ds
, "nl(len:%"PRIu32
", type=%"PRIu16
,
1126 h
->nlmsg_len
, h
->nlmsg_type
);
1127 if (h
->nlmsg_type
== NLMSG_NOOP
) {
1128 ds_put_cstr(ds
, "(no-op)");
1129 } else if (h
->nlmsg_type
== NLMSG_ERROR
) {
1130 ds_put_cstr(ds
, "(error)");
1131 } else if (h
->nlmsg_type
== NLMSG_DONE
) {
1132 ds_put_cstr(ds
, "(done)");
1133 } else if (h
->nlmsg_type
== NLMSG_OVERRUN
) {
1134 ds_put_cstr(ds
, "(overrun)");
1135 } else if (h
->nlmsg_type
< NLMSG_MIN_TYPE
) {
1136 ds_put_cstr(ds
, "(reserved)");
1137 } else if (protocol
== NETLINK_GENERIC
) {
1138 ds_put_format(ds
, "(%s)", genl_family_to_name(h
->nlmsg_type
));
1140 ds_put_cstr(ds
, "(family-defined)");
1142 ds_put_format(ds
, ", flags=%"PRIx16
, h
->nlmsg_flags
);
1143 flags_left
= h
->nlmsg_flags
;
1144 for (flag
= flags
; flag
< &flags
[ARRAY_SIZE(flags
)]; flag
++) {
1145 if ((flags_left
& flag
->bits
) == flag
->bits
) {
1146 ds_put_format(ds
, "[%s]", flag
->name
);
1147 flags_left
&= ~flag
->bits
;
1151 ds_put_format(ds
, "[OTHER:%"PRIx16
"]", flags_left
);
1153 ds_put_format(ds
, ", seq=%"PRIx32
", pid=%"PRIu32
,
1154 h
->nlmsg_seq
, h
->nlmsg_pid
);
1158 nlmsg_to_string(const struct ofpbuf
*buffer
, int protocol
)
1160 struct ds ds
= DS_EMPTY_INITIALIZER
;
1161 const struct nlmsghdr
*h
= ofpbuf_at(buffer
, 0, NLMSG_HDRLEN
);
1163 nlmsghdr_to_string(h
, protocol
, &ds
);
1164 if (h
->nlmsg_type
== NLMSG_ERROR
) {
1165 const struct nlmsgerr
*e
;
1166 e
= ofpbuf_at(buffer
, NLMSG_HDRLEN
,
1167 NLMSG_ALIGN(sizeof(struct nlmsgerr
)));
1169 ds_put_format(&ds
, " error(%d", e
->error
);
1171 ds_put_format(&ds
, "(%s)", ovs_strerror(-e
->error
));
1173 ds_put_cstr(&ds
, ", in-reply-to(");
1174 nlmsghdr_to_string(&e
->msg
, protocol
, &ds
);
1175 ds_put_cstr(&ds
, "))");
1177 ds_put_cstr(&ds
, " error(truncated)");
1179 } else if (h
->nlmsg_type
== NLMSG_DONE
) {
1180 int *error
= ofpbuf_at(buffer
, NLMSG_HDRLEN
, sizeof *error
);
1182 ds_put_format(&ds
, " done(%d", *error
);
1184 ds_put_format(&ds
, "(%s)", ovs_strerror(-*error
));
1186 ds_put_cstr(&ds
, ")");
1188 ds_put_cstr(&ds
, " done(truncated)");
1190 } else if (protocol
== NETLINK_GENERIC
) {
1191 struct genlmsghdr
*genl
= nl_msg_genlmsghdr(buffer
);
1193 ds_put_format(&ds
, ",genl(cmd=%"PRIu8
",version=%"PRIu8
")",
1194 genl
->cmd
, genl
->version
);
1198 ds_put_cstr(&ds
, "nl(truncated)");
1204 log_nlmsg(const char *function
, int error
,
1205 const void *message
, size_t size
, int protocol
)
1207 struct ofpbuf buffer
;
1210 if (!VLOG_IS_DBG_ENABLED()) {
1214 ofpbuf_use_const(&buffer
, message
, size
);
1215 nlmsg
= nlmsg_to_string(&buffer
, protocol
);
1216 VLOG_DBG_RL(&rl
, "%s (%s): %s", function
, ovs_strerror(error
), nlmsg
);