2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 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"
35 #include "socket-util.h"
39 VLOG_DEFINE_THIS_MODULE(netlink_socket
);
41 COVERAGE_DEFINE(netlink_overflow
);
42 COVERAGE_DEFINE(netlink_received
);
43 COVERAGE_DEFINE(netlink_recv_jumbo
);
44 COVERAGE_DEFINE(netlink_sent
);
46 /* Linux header file confusion causes this to be undefined. */
48 #define SOL_NETLINK 270
51 /* A single (bad) Netlink message can in theory dump out many, many log
52 * messages, so the burst size is set quite high here to avoid missing useful
53 * information. Also, at high logging levels we log *all* Netlink messages. */
54 static struct vlog_rate_limit rl
= VLOG_RATE_LIMIT_INIT(60, 600);
56 static uint32_t nl_sock_allocate_seq(struct nl_sock
*, unsigned int n
);
57 static void log_nlmsg(const char *function
, int error
,
58 const void *message
, size_t size
, int protocol
);
60 /* Netlink sockets. */
67 unsigned int rcvbuf
; /* Receive buffer size (SO_RCVBUF). */
70 /* Compile-time limit on iovecs, so that we can allocate a maximum-size array
71 * of iovecs on the stack. */
74 /* Maximum number of iovecs that may be passed to sendmsg, capped at a
75 * minimum of _XOPEN_IOV_MAX (16) and a maximum of MAX_IOVS.
77 * Initialized by nl_sock_create(). */
80 static int nl_pool_alloc(int protocol
, struct nl_sock
**sockp
);
81 static void nl_pool_release(struct nl_sock
*);
83 /* Creates a new netlink socket for the given netlink 'protocol'
84 * (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the
85 * new socket if successful, otherwise returns a positive errno value. */
87 nl_sock_create(int protocol
, struct nl_sock
**sockp
)
89 static struct ovsthread_once once
= OVSTHREAD_ONCE_INITIALIZER
;
91 struct sockaddr_nl local
, remote
;
96 if (ovsthread_once_start(&once
)) {
97 int save_errno
= errno
;
100 max_iovs
= sysconf(_SC_UIO_MAXIOV
);
101 if (max_iovs
< _XOPEN_IOV_MAX
) {
102 if (max_iovs
== -1 && errno
) {
103 VLOG_WARN("sysconf(_SC_UIO_MAXIOV): %s", ovs_strerror(errno
));
105 max_iovs
= _XOPEN_IOV_MAX
;
106 } else if (max_iovs
> MAX_IOVS
) {
111 ovsthread_once_done(&once
);
115 sock
= xmalloc(sizeof *sock
);
117 sock
->fd
= socket(AF_NETLINK
, SOCK_RAW
, protocol
);
119 VLOG_ERR("fcntl: %s", ovs_strerror(errno
));
122 sock
->protocol
= protocol
;
125 rcvbuf
= 1024 * 1024;
126 if (setsockopt(sock
->fd
, SOL_SOCKET
, SO_RCVBUFFORCE
,
127 &rcvbuf
, sizeof rcvbuf
)) {
128 /* Only root can use SO_RCVBUFFORCE. Everyone else gets EPERM.
129 * Warn only if the failure is therefore unexpected. */
130 if (errno
!= EPERM
) {
131 VLOG_WARN_RL(&rl
, "setting %d-byte socket receive buffer failed "
132 "(%s)", rcvbuf
, ovs_strerror(errno
));
136 retval
= get_socket_rcvbuf(sock
->fd
);
141 sock
->rcvbuf
= retval
;
143 /* Connect to kernel (pid 0) as remote address. */
144 memset(&remote
, 0, sizeof remote
);
145 remote
.nl_family
= AF_NETLINK
;
147 if (connect(sock
->fd
, (struct sockaddr
*) &remote
, sizeof remote
) < 0) {
148 VLOG_ERR("connect(0): %s", ovs_strerror(errno
));
152 /* Obtain pid assigned by kernel. */
153 local_size
= sizeof local
;
154 if (getsockname(sock
->fd
, (struct sockaddr
*) &local
, &local_size
) < 0) {
155 VLOG_ERR("getsockname: %s", ovs_strerror(errno
));
158 if (local_size
< sizeof local
|| local
.nl_family
!= AF_NETLINK
) {
159 VLOG_ERR("getsockname returned bad Netlink name");
163 sock
->pid
= local
.nl_pid
;
182 /* Creates a new netlink socket for the same protocol as 'src'. Returns 0 and
183 * sets '*sockp' to the new socket if successful, otherwise returns a positive
186 nl_sock_clone(const struct nl_sock
*src
, struct nl_sock
**sockp
)
188 return nl_sock_create(src
->protocol
, sockp
);
191 /* Destroys netlink socket 'sock'. */
193 nl_sock_destroy(struct nl_sock
*sock
)
201 /* Tries to add 'sock' as a listener for 'multicast_group'. Returns 0 if
202 * successful, otherwise a positive errno value.
204 * A socket that is subscribed to a multicast group that receives asynchronous
205 * notifications must not be used for Netlink transactions or dumps, because
206 * transactions and dumps can cause notifications to be lost.
208 * Multicast group numbers are always positive.
210 * It is not an error to attempt to join a multicast group to which a socket
211 * already belongs. */
213 nl_sock_join_mcgroup(struct nl_sock
*sock
, unsigned int multicast_group
)
215 if (setsockopt(sock
->fd
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
,
216 &multicast_group
, sizeof multicast_group
) < 0) {
217 VLOG_WARN("could not join multicast group %u (%s)",
218 multicast_group
, ovs_strerror(errno
));
224 /* Tries to make 'sock' stop listening to 'multicast_group'. Returns 0 if
225 * successful, otherwise a positive errno value.
227 * Multicast group numbers are always positive.
229 * It is not an error to attempt to leave a multicast group to which a socket
232 * On success, reading from 'sock' will still return any messages that were
233 * received on 'multicast_group' before the group was left. */
235 nl_sock_leave_mcgroup(struct nl_sock
*sock
, unsigned int multicast_group
)
237 if (setsockopt(sock
->fd
, SOL_NETLINK
, NETLINK_DROP_MEMBERSHIP
,
238 &multicast_group
, sizeof multicast_group
) < 0) {
239 VLOG_WARN("could not leave multicast group %u (%s)",
240 multicast_group
, ovs_strerror(errno
));
247 nl_sock_send__(struct nl_sock
*sock
, const struct ofpbuf
*msg
,
248 uint32_t nlmsg_seq
, bool wait
)
250 struct nlmsghdr
*nlmsg
= nl_msg_nlmsghdr(msg
);
253 nlmsg
->nlmsg_len
= ofpbuf_size(msg
);
254 nlmsg
->nlmsg_seq
= nlmsg_seq
;
255 nlmsg
->nlmsg_pid
= sock
->pid
;
258 retval
= send(sock
->fd
, ofpbuf_data(msg
), ofpbuf_size(msg
), wait
? 0 : MSG_DONTWAIT
);
259 error
= retval
< 0 ? errno
: 0;
260 } while (error
== EINTR
);
261 log_nlmsg(__func__
, error
, ofpbuf_data(msg
), ofpbuf_size(msg
), sock
->protocol
);
263 COVERAGE_INC(netlink_sent
);
268 /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
269 * 'sock'. nlmsg_len in 'msg' will be finalized to match ofpbuf_size(msg), nlmsg_pid
270 * will be set to 'sock''s pid, and nlmsg_seq will be initialized to a fresh
271 * sequence number, before the message is sent.
273 * Returns 0 if successful, otherwise a positive errno value. If
274 * 'wait' is true, then the send will wait until buffer space is ready;
275 * otherwise, returns EAGAIN if the 'sock' send buffer is full. */
277 nl_sock_send(struct nl_sock
*sock
, const struct ofpbuf
*msg
, bool wait
)
279 return nl_sock_send_seq(sock
, msg
, nl_sock_allocate_seq(sock
, 1), wait
);
282 /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
283 * 'sock'. nlmsg_len in 'msg' will be finalized to match ofpbuf_size(msg), nlmsg_pid
284 * will be set to 'sock''s pid, and nlmsg_seq will be initialized to
285 * 'nlmsg_seq', before the message is sent.
287 * Returns 0 if successful, otherwise a positive errno value. If
288 * 'wait' is true, then the send will wait until buffer space is ready;
289 * otherwise, returns EAGAIN if the 'sock' send buffer is full.
291 * This function is suitable for sending a reply to a request that was received
292 * with sequence number 'nlmsg_seq'. Otherwise, use nl_sock_send() instead. */
294 nl_sock_send_seq(struct nl_sock
*sock
, const struct ofpbuf
*msg
,
295 uint32_t nlmsg_seq
, bool wait
)
297 return nl_sock_send__(sock
, msg
, nlmsg_seq
, wait
);
301 nl_sock_recv__(struct nl_sock
*sock
, struct ofpbuf
*buf
, bool wait
)
303 /* We can't accurately predict the size of the data to be received. The
304 * caller is supposed to have allocated enough space in 'buf' to handle the
305 * "typical" case. To handle exceptions, we make available enough space in
306 * 'tail' to allow Netlink messages to be up to 64 kB long (a reasonable
307 * figure since that's the maximum length of a Netlink attribute). */
308 struct nlmsghdr
*nlmsghdr
;
315 ovs_assert(buf
->allocated
>= sizeof *nlmsghdr
);
318 iov
[0].iov_base
= ofpbuf_base(buf
);
319 iov
[0].iov_len
= buf
->allocated
;
320 iov
[1].iov_base
= tail
;
321 iov
[1].iov_len
= sizeof tail
;
323 memset(&msg
, 0, sizeof msg
);
327 /* Receive a Netlink message from the kernel.
329 * This works around a kernel bug in which the kernel returns an error code
330 * as if it were the number of bytes read. It doesn't actually modify
331 * anything in the receive buffer in that case, so we can initialize the
332 * Netlink header with an impossible message length and then, upon success,
333 * check whether it changed. */
334 nlmsghdr
= ofpbuf_base(buf
);
336 nlmsghdr
->nlmsg_len
= UINT32_MAX
;
337 retval
= recvmsg(sock
->fd
, &msg
, wait
? 0 : MSG_DONTWAIT
);
338 error
= (retval
< 0 ? errno
339 : retval
== 0 ? ECONNRESET
/* not possible? */
340 : nlmsghdr
->nlmsg_len
!= UINT32_MAX
? 0
342 } while (error
== EINTR
);
344 if (error
== ENOBUFS
) {
345 /* Socket receive buffer overflow dropped one or more messages that
346 * the kernel tried to send to us. */
347 COVERAGE_INC(netlink_overflow
);
352 if (msg
.msg_flags
& MSG_TRUNC
) {
353 VLOG_ERR_RL(&rl
, "truncated message (longer than %"PRIuSIZE
" bytes)",
358 if (retval
< sizeof *nlmsghdr
359 || nlmsghdr
->nlmsg_len
< sizeof *nlmsghdr
360 || nlmsghdr
->nlmsg_len
> retval
) {
361 VLOG_ERR_RL(&rl
, "received invalid nlmsg (%"PRIuSIZE
" bytes < %"PRIuSIZE
")",
362 retval
, sizeof *nlmsghdr
);
366 ofpbuf_set_size(buf
, MIN(retval
, buf
->allocated
));
367 if (retval
> buf
->allocated
) {
368 COVERAGE_INC(netlink_recv_jumbo
);
369 ofpbuf_put(buf
, tail
, retval
- buf
->allocated
);
372 log_nlmsg(__func__
, 0, ofpbuf_data(buf
), ofpbuf_size(buf
), sock
->protocol
);
373 COVERAGE_INC(netlink_received
);
378 /* Tries to receive a Netlink message from the kernel on 'sock' into 'buf'. If
379 * 'wait' is true, waits for a message to be ready. Otherwise, fails with
380 * EAGAIN if the 'sock' receive buffer is empty.
382 * The caller must have initialized 'buf' with an allocation of at least
383 * NLMSG_HDRLEN bytes. For best performance, the caller should allocate enough
384 * space for a "typical" message.
386 * On success, returns 0 and replaces 'buf''s previous content by the received
387 * message. This function expands 'buf''s allocated memory, as necessary, to
388 * hold the actual size of the received message.
390 * On failure, returns a positive errno value and clears 'buf' to zero length.
391 * 'buf' retains its previous memory allocation.
393 * Regardless of success or failure, this function resets 'buf''s headroom to
396 nl_sock_recv(struct nl_sock
*sock
, struct ofpbuf
*buf
, bool wait
)
398 return nl_sock_recv__(sock
, buf
, wait
);
402 nl_sock_record_errors__(struct nl_transaction
**transactions
, size_t n
,
407 for (i
= 0; i
< n
; i
++) {
408 struct nl_transaction
*txn
= transactions
[i
];
412 ofpbuf_clear(txn
->reply
);
418 nl_sock_transact_multiple__(struct nl_sock
*sock
,
419 struct nl_transaction
**transactions
, size_t n
,
422 uint64_t tmp_reply_stub
[1024 / 8];
423 struct nl_transaction tmp_txn
;
424 struct ofpbuf tmp_reply
;
427 struct iovec iovs
[MAX_IOVS
];
432 base_seq
= nl_sock_allocate_seq(sock
, n
);
434 for (i
= 0; i
< n
; i
++) {
435 struct nl_transaction
*txn
= transactions
[i
];
436 struct nlmsghdr
*nlmsg
= nl_msg_nlmsghdr(txn
->request
);
438 nlmsg
->nlmsg_len
= ofpbuf_size(txn
->request
);
439 nlmsg
->nlmsg_seq
= base_seq
+ i
;
440 nlmsg
->nlmsg_pid
= sock
->pid
;
442 iovs
[i
].iov_base
= ofpbuf_data(txn
->request
);
443 iovs
[i
].iov_len
= ofpbuf_size(txn
->request
);
446 memset(&msg
, 0, sizeof msg
);
450 error
= sendmsg(sock
->fd
, &msg
, 0) < 0 ? errno
: 0;
451 } while (error
== EINTR
);
453 for (i
= 0; i
< n
; i
++) {
454 struct nl_transaction
*txn
= transactions
[i
];
456 log_nlmsg(__func__
, error
, ofpbuf_data(txn
->request
), ofpbuf_size(txn
->request
),
460 COVERAGE_ADD(netlink_sent
, n
);
467 ofpbuf_use_stub(&tmp_reply
, tmp_reply_stub
, sizeof tmp_reply_stub
);
468 tmp_txn
.request
= NULL
;
469 tmp_txn
.reply
= &tmp_reply
;
472 struct nl_transaction
*buf_txn
, *txn
;
475 /* Find a transaction whose buffer we can use for receiving a reply.
476 * If no such transaction is left, use tmp_txn. */
478 for (i
= 0; i
< n
; i
++) {
479 if (transactions
[i
]->reply
) {
480 buf_txn
= transactions
[i
];
485 /* Receive a reply. */
486 error
= nl_sock_recv__(sock
, buf_txn
->reply
, false);
488 if (error
== EAGAIN
) {
489 nl_sock_record_errors__(transactions
, n
, 0);
496 /* Match the reply up with a transaction. */
497 seq
= nl_msg_nlmsghdr(buf_txn
->reply
)->nlmsg_seq
;
498 if (seq
< base_seq
|| seq
>= base_seq
+ n
) {
499 VLOG_DBG_RL(&rl
, "ignoring unexpected seq %#"PRIx32
, seq
);
503 txn
= transactions
[i
];
505 /* Fill in the results for 'txn'. */
506 if (nl_msg_nlmsgerr(buf_txn
->reply
, &txn
->error
)) {
508 ofpbuf_clear(txn
->reply
);
511 VLOG_DBG_RL(&rl
, "received NAK error=%d (%s)",
512 error
, ovs_strerror(txn
->error
));
516 if (txn
->reply
&& txn
!= buf_txn
) {
518 struct ofpbuf
*reply
= buf_txn
->reply
;
519 buf_txn
->reply
= txn
->reply
;
524 /* Fill in the results for transactions before 'txn'. (We have to do
525 * this after the results for 'txn' itself because of the buffer swap
527 nl_sock_record_errors__(transactions
, i
, 0);
531 transactions
+= i
+ 1;
535 ofpbuf_uninit(&tmp_reply
);
540 /* Sends the 'request' member of the 'n' transactions in 'transactions' on
541 * 'sock', in order, and receives responses to all of them. Fills in the
542 * 'error' member of each transaction with 0 if it was successful, otherwise
543 * with a positive errno value. If 'reply' is nonnull, then it will be filled
544 * with the reply if the message receives a detailed reply. In other cases,
545 * i.e. where the request failed or had no reply beyond an indication of
546 * success, 'reply' will be cleared if it is nonnull.
548 * The caller is responsible for destroying each request and reply, and the
549 * transactions array itself.
551 * Before sending each message, this function will finalize nlmsg_len in each
552 * 'request' to match the ofpbuf's size, set nlmsg_pid to 'sock''s pid, and
553 * initialize nlmsg_seq.
555 * Bare Netlink is an unreliable transport protocol. This function layers
556 * reliable delivery and reply semantics on top of bare Netlink. See
557 * nl_sock_transact() for some caveats.
560 nl_sock_transact_multiple(struct nl_sock
*sock
,
561 struct nl_transaction
**transactions
, size_t n
)
570 /* In theory, every request could have a 64 kB reply. But the default and
571 * maximum socket rcvbuf size with typical Dom0 memory sizes both tend to
572 * be a bit below 128 kB, so that would only allow a single message in a
573 * "batch". So we assume that replies average (at most) 4 kB, which allows
574 * a good deal of batching.
576 * In practice, most of the requests that we batch either have no reply at
577 * all or a brief reply. */
578 max_batch_count
= MAX(sock
->rcvbuf
/ 4096, 1);
579 max_batch_count
= MIN(max_batch_count
, max_iovs
);
585 /* Batch up to 'max_batch_count' transactions. But cap it at about a
586 * page of requests total because big skbuffs are expensive to
587 * allocate in the kernel. */
588 #if defined(PAGESIZE)
589 enum { MAX_BATCH_BYTES
= MAX(1, PAGESIZE
- 512) };
591 enum { MAX_BATCH_BYTES
= 4096 - 512 };
593 bytes
= ofpbuf_size(transactions
[0]->request
);
594 for (count
= 1; count
< n
&& count
< max_batch_count
; count
++) {
595 if (bytes
+ ofpbuf_size(transactions
[count
]->request
) > MAX_BATCH_BYTES
) {
598 bytes
+= ofpbuf_size(transactions
[count
]->request
);
601 error
= nl_sock_transact_multiple__(sock
, transactions
, count
, &done
);
602 transactions
+= done
;
605 if (error
== ENOBUFS
) {
606 VLOG_DBG_RL(&rl
, "receive buffer overflow, resending request");
608 VLOG_ERR_RL(&rl
, "transaction error (%s)", ovs_strerror(error
));
609 nl_sock_record_errors__(transactions
, n
, error
);
614 /* Sends 'request' to the kernel via 'sock' and waits for a response. If
615 * successful, returns 0. On failure, returns a positive errno value.
617 * If 'replyp' is nonnull, then on success '*replyp' is set to the kernel's
618 * reply, which the caller is responsible for freeing with ofpbuf_delete(), and
619 * on failure '*replyp' is set to NULL. If 'replyp' is null, then the kernel's
620 * reply, if any, is discarded.
622 * Before the message is sent, nlmsg_len in 'request' will be finalized to
623 * match ofpbuf_size(msg), nlmsg_pid will be set to 'sock''s pid, and nlmsg_seq will
624 * be initialized, NLM_F_ACK will be set in nlmsg_flags.
626 * The caller is responsible for destroying 'request'.
628 * Bare Netlink is an unreliable transport protocol. This function layers
629 * reliable delivery and reply semantics on top of bare Netlink.
631 * In Netlink, sending a request to the kernel is reliable enough, because the
632 * kernel will tell us if the message cannot be queued (and we will in that
633 * case put it on the transmit queue and wait until it can be delivered).
635 * Receiving the reply is the real problem: if the socket buffer is full when
636 * the kernel tries to send the reply, the reply will be dropped. However, the
637 * kernel sets a flag that a reply has been dropped. The next call to recv
638 * then returns ENOBUFS. We can then re-send the request.
642 * 1. Netlink depends on sequence numbers to match up requests and
643 * replies. The sender of a request supplies a sequence number, and
644 * the reply echos back that sequence number.
646 * This is fine, but (1) some kernel netlink implementations are
647 * broken, in that they fail to echo sequence numbers and (2) this
648 * function will drop packets with non-matching sequence numbers, so
649 * that only a single request can be usefully transacted at a time.
651 * 2. Resending the request causes it to be re-executed, so the request
652 * needs to be idempotent.
655 nl_sock_transact(struct nl_sock
*sock
, const struct ofpbuf
*request
,
656 struct ofpbuf
**replyp
)
658 struct nl_transaction
*transactionp
;
659 struct nl_transaction transaction
;
661 transaction
.request
= CONST_CAST(struct ofpbuf
*, request
);
662 transaction
.reply
= replyp
? ofpbuf_new(1024) : NULL
;
663 transactionp
= &transaction
;
665 nl_sock_transact_multiple(sock
, &transactionp
, 1);
668 if (transaction
.error
) {
669 ofpbuf_delete(transaction
.reply
);
672 *replyp
= transaction
.reply
;
676 return transaction
.error
;
679 /* Drain all the messages currently in 'sock''s receive queue. */
681 nl_sock_drain(struct nl_sock
*sock
)
683 return drain_rcvbuf(sock
->fd
);
686 /* Starts a Netlink "dump" operation, by sending 'request' to the kernel on a
687 * Netlink socket created with the given 'protocol', and initializes 'dump' to
688 * reflect the state of the operation.
690 * 'request' must contain a Netlink message. Before sending the message,
691 * nlmsg_len will be finalized to match request->size, and nlmsg_pid will be
692 * set to the Netlink socket's pid. NLM_F_DUMP and NLM_F_ACK will be set in
695 * The design of this Netlink socket library ensures that the dump is reliable.
697 * This function provides no status indication. nl_dump_done() provides an
698 * error status for the entire dump operation.
700 * The caller must eventually destroy 'request'.
703 nl_dump_start(struct nl_dump
*dump
, int protocol
, const struct ofpbuf
*request
)
705 int status
= nl_pool_alloc(protocol
, &dump
->sock
);
711 nl_msg_nlmsghdr(request
)->nlmsg_flags
|= NLM_F_DUMP
| NLM_F_ACK
;
712 status
= nl_sock_send__(dump
->sock
, request
,
713 nl_sock_allocate_seq(dump
->sock
, 1), true);
714 atomic_init(&dump
->status
, status
<< 1);
715 dump
->nl_seq
= nl_msg_nlmsghdr(request
)->nlmsg_seq
;
716 dump
->status_seq
= seq_create();
717 ovs_mutex_init(&dump
->mutex
);
720 /* Attempts to retrieve another reply from 'dump' into 'buffer'. 'dump' must
721 * have been initialized with nl_dump_start(), and 'buffer' must have been
722 * initialized. 'buffer' should be at least NL_DUMP_BUFSIZE bytes long.
724 * If successful, returns true and points 'reply->data' and
725 * 'ofpbuf_size(reply)' to the message that was retrieved. The caller must not
726 * modify 'reply' (because it points within 'buffer', which will be used by
727 * future calls to this function).
729 * On failure, returns false and sets 'reply->data' to NULL and
730 * 'ofpbuf_size(reply)' to 0. Failure might indicate an actual error or merely
731 * the end of replies. An error status for the entire dump operation is
732 * provided when it is completed by calling nl_dump_done().
734 * Multiple threads may call this function, passing the same nl_dump, however
735 * each must provide independent buffers. This function may cache multiple
736 * replies in the buffer, and these will be processed before more replies are
737 * fetched. When this function returns false, other threads may continue to
738 * process replies in their buffers, but they will not fetch more replies.
741 nl_dump_next(struct nl_dump
*dump
, struct ofpbuf
*reply
, struct ofpbuf
*buffer
)
743 struct nlmsghdr
*nlmsghdr
;
746 ofpbuf_set_data(reply
, NULL
);
747 ofpbuf_set_size(reply
, 0);
749 /* If 'buffer' is empty, fetch another batch of nlmsgs. */
750 while (!ofpbuf_size(buffer
)) {
754 seq
= seq_read(dump
->status_seq
);
755 atomic_read(&dump
->status
, &status
);
760 /* Take the mutex here to avoid an in-kernel race. If two threads try
761 * to read from a Netlink dump socket at once, then the socket error
762 * can be set to EINVAL, which will be encountered on the next recv on
763 * that socket, which could be anywhere due to the way that we pool
764 * Netlink sockets. Serializing the recv calls avoids the issue. */
765 ovs_mutex_lock(&dump
->mutex
);
766 retval
= nl_sock_recv__(dump
->sock
, buffer
, false);
767 ovs_mutex_unlock(&dump
->mutex
);
770 ofpbuf_clear(buffer
);
771 if (retval
== EAGAIN
) {
772 nl_sock_wait(dump
->sock
, POLLIN
);
773 seq_wait(dump
->status_seq
, seq
);
782 nlmsghdr
= nl_msg_nlmsghdr(buffer
);
783 if (dump
->nl_seq
!= nlmsghdr
->nlmsg_seq
) {
784 VLOG_DBG_RL(&rl
, "ignoring seq %#"PRIx32
" != expected %#"PRIx32
,
785 nlmsghdr
->nlmsg_seq
, dump
->nl_seq
);
786 ofpbuf_clear(buffer
);
790 if (nl_msg_nlmsgerr(buffer
, &retval
) && retval
) {
791 VLOG_INFO_RL(&rl
, "netlink dump request error (%s)",
792 ovs_strerror(retval
));
793 error
= retval
== EAGAIN
? EPROTO
: retval
;
794 ofpbuf_clear(buffer
);
799 /* Fetch the next nlmsg in the current batch. */
800 nlmsghdr
= nl_msg_next(buffer
, reply
);
802 VLOG_WARN_RL(&rl
, "netlink dump reply contains message fragment");
804 } else if (nlmsghdr
->nlmsg_type
== NLMSG_DONE
) {
811 atomic_or(&dump
->status
, 1, &old
);
812 seq_change(dump
->status_seq
);
814 atomic_store(&dump
->status
, error
<< 1);
815 seq_change(dump
->status_seq
);
820 /* Completes Netlink dump operation 'dump', which must have been initialized
821 * with nl_dump_start(). Returns 0 if the dump operation was error-free,
822 * otherwise a positive errno value describing the problem. */
824 nl_dump_done(struct nl_dump
*dump
)
828 /* Drain any remaining messages that the client didn't read. Otherwise the
829 * kernel will continue to queue them up and waste buffer space.
831 * XXX We could just destroy and discard the socket in this case. */
832 atomic_read(&dump
->status
, &status
);
834 uint64_t tmp_reply_stub
[NL_DUMP_BUFSIZE
/ 8];
835 struct ofpbuf reply
, buf
;
837 ofpbuf_use_stub(&buf
, tmp_reply_stub
, sizeof tmp_reply_stub
);
838 while (nl_dump_next(dump
, &reply
, &buf
)) {
841 atomic_read(&dump
->status
, &status
);
845 nl_pool_release(dump
->sock
);
846 seq_destroy(dump
->status_seq
);
847 ovs_mutex_destroy(&dump
->mutex
);
851 /* Causes poll_block() to wake up when any of the specified 'events' (which is
852 * a OR'd combination of POLLIN, POLLOUT, etc.) occur on 'sock'. */
854 nl_sock_wait(const struct nl_sock
*sock
, short int events
)
856 poll_fd_wait(sock
->fd
, events
);
859 /* Returns the underlying fd for 'sock', for use in "poll()"-like operations
860 * that can't use nl_sock_wait().
862 * It's a little tricky to use the returned fd correctly, because nl_sock does
863 * "copy on write" to allow a single nl_sock to be used for notifications,
864 * transactions, and dumps. If 'sock' is used only for notifications and
865 * transactions (and never for dump) then the usage is safe. */
867 nl_sock_fd(const struct nl_sock
*sock
)
872 /* Returns the PID associated with this socket. */
874 nl_sock_pid(const struct nl_sock
*sock
)
882 struct hmap_node hmap_node
;
887 static struct hmap genl_families
= HMAP_INITIALIZER(&genl_families
);
889 static const struct nl_policy family_policy
[CTRL_ATTR_MAX
+ 1] = {
890 [CTRL_ATTR_FAMILY_ID
] = {.type
= NL_A_U16
},
891 [CTRL_ATTR_MCAST_GROUPS
] = {.type
= NL_A_NESTED
, .optional
= true},
894 static struct genl_family
*
895 find_genl_family_by_id(uint16_t id
)
897 struct genl_family
*family
;
899 HMAP_FOR_EACH_IN_BUCKET (family
, hmap_node
, hash_int(id
, 0),
901 if (family
->id
== id
) {
909 define_genl_family(uint16_t id
, const char *name
)
911 struct genl_family
*family
= find_genl_family_by_id(id
);
914 if (!strcmp(family
->name
, name
)) {
919 family
= xmalloc(sizeof *family
);
921 hmap_insert(&genl_families
, &family
->hmap_node
, hash_int(id
, 0));
923 family
->name
= xstrdup(name
);
927 genl_family_to_name(uint16_t id
)
929 if (id
== GENL_ID_CTRL
) {
932 struct genl_family
*family
= find_genl_family_by_id(id
);
933 return family
? family
->name
: "unknown";
938 do_lookup_genl_family(const char *name
, struct nlattr
**attrs
,
939 struct ofpbuf
**replyp
)
941 struct nl_sock
*sock
;
942 struct ofpbuf request
, *reply
;
946 error
= nl_sock_create(NETLINK_GENERIC
, &sock
);
951 ofpbuf_init(&request
, 0);
952 nl_msg_put_genlmsghdr(&request
, 0, GENL_ID_CTRL
, NLM_F_REQUEST
,
953 CTRL_CMD_GETFAMILY
, 1);
954 nl_msg_put_string(&request
, CTRL_ATTR_FAMILY_NAME
, name
);
955 error
= nl_sock_transact(sock
, &request
, &reply
);
956 ofpbuf_uninit(&request
);
958 nl_sock_destroy(sock
);
962 if (!nl_policy_parse(reply
, NLMSG_HDRLEN
+ GENL_HDRLEN
,
963 family_policy
, attrs
, ARRAY_SIZE(family_policy
))
964 || nl_attr_get_u16(attrs
[CTRL_ATTR_FAMILY_ID
]) == 0) {
965 nl_sock_destroy(sock
);
966 ofpbuf_delete(reply
);
970 nl_sock_destroy(sock
);
975 /* Finds the multicast group called 'group_name' in genl family 'family_name'.
976 * When successful, writes its result to 'multicast_group' and returns 0.
977 * Otherwise, clears 'multicast_group' and returns a positive error code.
980 nl_lookup_genl_mcgroup(const char *family_name
, const char *group_name
,
981 unsigned int *multicast_group
)
983 struct nlattr
*family_attrs
[ARRAY_SIZE(family_policy
)];
984 const struct nlattr
*mc
;
985 struct ofpbuf
*reply
;
989 *multicast_group
= 0;
990 error
= do_lookup_genl_family(family_name
, family_attrs
, &reply
);
995 if (!family_attrs
[CTRL_ATTR_MCAST_GROUPS
]) {
1000 NL_NESTED_FOR_EACH (mc
, left
, family_attrs
[CTRL_ATTR_MCAST_GROUPS
]) {
1001 static const struct nl_policy mc_policy
[] = {
1002 [CTRL_ATTR_MCAST_GRP_ID
] = {.type
= NL_A_U32
},
1003 [CTRL_ATTR_MCAST_GRP_NAME
] = {.type
= NL_A_STRING
},
1006 struct nlattr
*mc_attrs
[ARRAY_SIZE(mc_policy
)];
1007 const char *mc_name
;
1009 if (!nl_parse_nested(mc
, mc_policy
, mc_attrs
, ARRAY_SIZE(mc_policy
))) {
1014 mc_name
= nl_attr_get_string(mc_attrs
[CTRL_ATTR_MCAST_GRP_NAME
]);
1015 if (!strcmp(group_name
, mc_name
)) {
1017 nl_attr_get_u32(mc_attrs
[CTRL_ATTR_MCAST_GRP_ID
]);
1025 ofpbuf_delete(reply
);
1029 /* If '*number' is 0, translates the given Generic Netlink family 'name' to a
1030 * number and stores it in '*number'. If successful, returns 0 and the caller
1031 * may use '*number' as the family number. On failure, returns a positive
1032 * errno value and '*number' caches the errno value. */
1034 nl_lookup_genl_family(const char *name
, int *number
)
1037 struct nlattr
*attrs
[ARRAY_SIZE(family_policy
)];
1038 struct ofpbuf
*reply
;
1041 error
= do_lookup_genl_family(name
, attrs
, &reply
);
1043 *number
= nl_attr_get_u16(attrs
[CTRL_ATTR_FAMILY_ID
]);
1044 define_genl_family(*number
, name
);
1048 ofpbuf_delete(reply
);
1050 ovs_assert(*number
!= 0);
1052 return *number
> 0 ? 0 : -*number
;
1056 struct nl_sock
*socks
[16];
1060 static struct ovs_mutex pool_mutex
= OVS_MUTEX_INITIALIZER
;
1061 static struct nl_pool pools
[MAX_LINKS
] OVS_GUARDED_BY(pool_mutex
);
1064 nl_pool_alloc(int protocol
, struct nl_sock
**sockp
)
1066 struct nl_sock
*sock
= NULL
;
1067 struct nl_pool
*pool
;
1069 ovs_assert(protocol
>= 0 && protocol
< ARRAY_SIZE(pools
));
1071 ovs_mutex_lock(&pool_mutex
);
1072 pool
= &pools
[protocol
];
1074 sock
= pool
->socks
[--pool
->n
];
1076 ovs_mutex_unlock(&pool_mutex
);
1082 return nl_sock_create(protocol
, sockp
);
1087 nl_pool_release(struct nl_sock
*sock
)
1090 struct nl_pool
*pool
= &pools
[sock
->protocol
];
1092 ovs_mutex_lock(&pool_mutex
);
1093 if (pool
->n
< ARRAY_SIZE(pool
->socks
)) {
1094 pool
->socks
[pool
->n
++] = sock
;
1097 ovs_mutex_unlock(&pool_mutex
);
1099 nl_sock_destroy(sock
);
1104 nl_transact(int protocol
, const struct ofpbuf
*request
,
1105 struct ofpbuf
**replyp
)
1107 struct nl_sock
*sock
;
1110 error
= nl_pool_alloc(protocol
, &sock
);
1116 error
= nl_sock_transact(sock
, request
, replyp
);
1118 nl_pool_release(sock
);
1123 nl_transact_multiple(int protocol
,
1124 struct nl_transaction
**transactions
, size_t n
)
1126 struct nl_sock
*sock
;
1129 error
= nl_pool_alloc(protocol
, &sock
);
1131 nl_sock_transact_multiple(sock
, transactions
, n
);
1132 nl_pool_release(sock
);
1134 nl_sock_record_errors__(transactions
, n
, error
);
1140 nl_sock_allocate_seq(struct nl_sock
*sock
, unsigned int n
)
1142 uint32_t seq
= sock
->next_seq
;
1144 sock
->next_seq
+= n
;
1146 /* Make it impossible for the next request for sequence numbers to wrap
1147 * around to 0. Start over with 1 to avoid ever using a sequence number of
1148 * 0, because the kernel uses sequence number 0 for notifications. */
1149 if (sock
->next_seq
>= UINT32_MAX
/ 2) {
1157 nlmsghdr_to_string(const struct nlmsghdr
*h
, int protocol
, struct ds
*ds
)
1163 static const struct nlmsg_flag flags
[] = {
1164 { NLM_F_REQUEST
, "REQUEST" },
1165 { NLM_F_MULTI
, "MULTI" },
1166 { NLM_F_ACK
, "ACK" },
1167 { NLM_F_ECHO
, "ECHO" },
1168 { NLM_F_DUMP
, "DUMP" },
1169 { NLM_F_ROOT
, "ROOT" },
1170 { NLM_F_MATCH
, "MATCH" },
1171 { NLM_F_ATOMIC
, "ATOMIC" },
1173 const struct nlmsg_flag
*flag
;
1174 uint16_t flags_left
;
1176 ds_put_format(ds
, "nl(len:%"PRIu32
", type=%"PRIu16
,
1177 h
->nlmsg_len
, h
->nlmsg_type
);
1178 if (h
->nlmsg_type
== NLMSG_NOOP
) {
1179 ds_put_cstr(ds
, "(no-op)");
1180 } else if (h
->nlmsg_type
== NLMSG_ERROR
) {
1181 ds_put_cstr(ds
, "(error)");
1182 } else if (h
->nlmsg_type
== NLMSG_DONE
) {
1183 ds_put_cstr(ds
, "(done)");
1184 } else if (h
->nlmsg_type
== NLMSG_OVERRUN
) {
1185 ds_put_cstr(ds
, "(overrun)");
1186 } else if (h
->nlmsg_type
< NLMSG_MIN_TYPE
) {
1187 ds_put_cstr(ds
, "(reserved)");
1188 } else if (protocol
== NETLINK_GENERIC
) {
1189 ds_put_format(ds
, "(%s)", genl_family_to_name(h
->nlmsg_type
));
1191 ds_put_cstr(ds
, "(family-defined)");
1193 ds_put_format(ds
, ", flags=%"PRIx16
, h
->nlmsg_flags
);
1194 flags_left
= h
->nlmsg_flags
;
1195 for (flag
= flags
; flag
< &flags
[ARRAY_SIZE(flags
)]; flag
++) {
1196 if ((flags_left
& flag
->bits
) == flag
->bits
) {
1197 ds_put_format(ds
, "[%s]", flag
->name
);
1198 flags_left
&= ~flag
->bits
;
1202 ds_put_format(ds
, "[OTHER:%"PRIx16
"]", flags_left
);
1204 ds_put_format(ds
, ", seq=%"PRIx32
", pid=%"PRIu32
,
1205 h
->nlmsg_seq
, h
->nlmsg_pid
);
1209 nlmsg_to_string(const struct ofpbuf
*buffer
, int protocol
)
1211 struct ds ds
= DS_EMPTY_INITIALIZER
;
1212 const struct nlmsghdr
*h
= ofpbuf_at(buffer
, 0, NLMSG_HDRLEN
);
1214 nlmsghdr_to_string(h
, protocol
, &ds
);
1215 if (h
->nlmsg_type
== NLMSG_ERROR
) {
1216 const struct nlmsgerr
*e
;
1217 e
= ofpbuf_at(buffer
, NLMSG_HDRLEN
,
1218 NLMSG_ALIGN(sizeof(struct nlmsgerr
)));
1220 ds_put_format(&ds
, " error(%d", e
->error
);
1222 ds_put_format(&ds
, "(%s)", ovs_strerror(-e
->error
));
1224 ds_put_cstr(&ds
, ", in-reply-to(");
1225 nlmsghdr_to_string(&e
->msg
, protocol
, &ds
);
1226 ds_put_cstr(&ds
, "))");
1228 ds_put_cstr(&ds
, " error(truncated)");
1230 } else if (h
->nlmsg_type
== NLMSG_DONE
) {
1231 int *error
= ofpbuf_at(buffer
, NLMSG_HDRLEN
, sizeof *error
);
1233 ds_put_format(&ds
, " done(%d", *error
);
1235 ds_put_format(&ds
, "(%s)", ovs_strerror(-*error
));
1237 ds_put_cstr(&ds
, ")");
1239 ds_put_cstr(&ds
, " done(truncated)");
1241 } else if (protocol
== NETLINK_GENERIC
) {
1242 struct genlmsghdr
*genl
= nl_msg_genlmsghdr(buffer
);
1244 ds_put_format(&ds
, ",genl(cmd=%"PRIu8
",version=%"PRIu8
")",
1245 genl
->cmd
, genl
->version
);
1249 ds_put_cstr(&ds
, "nl(truncated)");
1255 log_nlmsg(const char *function
, int error
,
1256 const void *message
, size_t size
, int protocol
)
1258 struct ofpbuf buffer
;
1261 if (!VLOG_IS_DBG_ENABLED()) {
1265 ofpbuf_use_const(&buffer
, message
, size
);
1266 nlmsg
= nlmsg_to_string(&buffer
, protocol
);
1267 VLOG_DBG_RL(&rl
, "%s (%s): %s", function
, ovs_strerror(error
), nlmsg
);