2 * Copyright (c) 2008, 2009, 2010, 2011, 2012 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"
23 #include <sys/types.h>
27 #include "dynamic-string.h"
31 #include "netlink-protocol.h"
33 #include "poll-loop.h"
34 #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_send
);
45 COVERAGE_DEFINE(netlink_sent
);
47 /* Linux header file confusion causes this to be undefined. */
49 #define SOL_NETLINK 270
52 /* A single (bad) Netlink message can in theory dump out many, many log
53 * messages, so the burst size is set quite high here to avoid missing useful
54 * information. Also, at high logging levels we log *all* Netlink messages. */
55 static struct vlog_rate_limit rl
= VLOG_RATE_LIMIT_INIT(60, 600);
57 static uint32_t nl_sock_allocate_seq(struct nl_sock
*, unsigned int n
);
58 static void log_nlmsg(const char *function
, int error
,
59 const void *message
, size_t size
, int protocol
);
61 /* Netlink sockets. */
70 unsigned int rcvbuf
; /* Receive buffer size (SO_RCVBUF). */
73 /* Compile-time limit on iovecs, so that we can allocate a maximum-size array
74 * of iovecs on the stack. */
77 /* Maximum number of iovecs that may be passed to sendmsg, capped at a
78 * minimum of _XOPEN_IOV_MAX (16) and a maximum of MAX_IOVS.
80 * Initialized by nl_sock_create(). */
83 static int nl_sock_cow__(struct nl_sock
*);
85 /* Creates a new netlink socket for the given netlink 'protocol'
86 * (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the
87 * new socket if successful, otherwise returns a positive errno value. */
89 nl_sock_create(int protocol
, struct nl_sock
**sockp
)
92 struct sockaddr_nl local
, remote
;
98 int save_errno
= errno
;
101 max_iovs
= sysconf(_SC_UIO_MAXIOV
);
102 if (max_iovs
< _XOPEN_IOV_MAX
) {
103 if (max_iovs
== -1 && errno
) {
104 VLOG_WARN("sysconf(_SC_UIO_MAXIOV): %s", strerror(errno
));
106 max_iovs
= _XOPEN_IOV_MAX
;
107 } else if (max_iovs
> MAX_IOVS
) {
115 sock
= malloc(sizeof *sock
);
120 sock
->fd
= socket(AF_NETLINK
, SOCK_RAW
, protocol
);
122 VLOG_ERR("fcntl: %s", strerror(errno
));
125 sock
->protocol
= protocol
;
129 rcvbuf
= 1024 * 1024;
130 if (setsockopt(sock
->fd
, SOL_SOCKET
, SO_RCVBUFFORCE
,
131 &rcvbuf
, sizeof rcvbuf
)) {
132 VLOG_WARN_RL(&rl
, "setting %d-byte socket receive buffer failed (%s)",
133 rcvbuf
, 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", 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", 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
)
205 /* Tries to add 'sock' as a listener for 'multicast_group'. Returns 0 if
206 * successful, otherwise a positive errno value.
208 * A socket that is subscribed to a multicast group that receives asynchronous
209 * notifications must not be used for Netlink transactions or dumps, because
210 * transactions and dumps can cause notifications to be lost.
212 * Multicast group numbers are always positive.
214 * It is not an error to attempt to join a multicast group to which a socket
215 * already belongs. */
217 nl_sock_join_mcgroup(struct nl_sock
*sock
, unsigned int multicast_group
)
219 int error
= nl_sock_cow__(sock
);
223 if (setsockopt(sock
->fd
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
,
224 &multicast_group
, sizeof multicast_group
) < 0) {
225 VLOG_WARN("could not join multicast group %u (%s)",
226 multicast_group
, strerror(errno
));
232 /* Tries to make 'sock' stop listening to 'multicast_group'. Returns 0 if
233 * successful, otherwise a positive errno value.
235 * Multicast group numbers are always positive.
237 * It is not an error to attempt to leave a multicast group to which a socket
240 * On success, reading from 'sock' will still return any messages that were
241 * received on 'multicast_group' before the group was left. */
243 nl_sock_leave_mcgroup(struct nl_sock
*sock
, unsigned int multicast_group
)
246 if (setsockopt(sock
->fd
, SOL_NETLINK
, NETLINK_DROP_MEMBERSHIP
,
247 &multicast_group
, sizeof multicast_group
) < 0) {
248 VLOG_WARN("could not leave multicast group %u (%s)",
249 multicast_group
, strerror(errno
));
256 nl_sock_send__(struct nl_sock
*sock
, const struct ofpbuf
*msg
,
257 uint32_t nlmsg_seq
, bool wait
)
259 struct nlmsghdr
*nlmsg
= nl_msg_nlmsghdr(msg
);
262 nlmsg
->nlmsg_len
= msg
->size
;
263 nlmsg
->nlmsg_seq
= nlmsg_seq
;
264 nlmsg
->nlmsg_pid
= sock
->pid
;
267 retval
= send(sock
->fd
, msg
->data
, msg
->size
, wait
? 0 : MSG_DONTWAIT
);
268 error
= retval
< 0 ? errno
: 0;
269 } while (error
== EINTR
);
270 log_nlmsg(__func__
, error
, msg
->data
, msg
->size
, sock
->protocol
);
272 COVERAGE_INC(netlink_sent
);
277 /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
278 * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
279 * will be set to 'sock''s pid, and nlmsg_seq will be initialized to a fresh
280 * sequence number, before the message is sent.
282 * Returns 0 if successful, otherwise a positive errno value. If
283 * 'wait' is true, then the send will wait until buffer space is ready;
284 * otherwise, returns EAGAIN if the 'sock' send buffer is full. */
286 nl_sock_send(struct nl_sock
*sock
, const struct ofpbuf
*msg
, bool wait
)
288 return nl_sock_send_seq(sock
, msg
, nl_sock_allocate_seq(sock
, 1), wait
);
291 /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
292 * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
293 * will be set to 'sock''s pid, and nlmsg_seq will be initialized to
294 * 'nlmsg_seq', before the message is sent.
296 * Returns 0 if successful, otherwise a positive errno value. If
297 * 'wait' is true, then the send will wait until buffer space is ready;
298 * otherwise, returns EAGAIN if the 'sock' send buffer is full.
300 * This function is suitable for sending a reply to a request that was received
301 * with sequence number 'nlmsg_seq'. Otherwise, use nl_sock_send() instead. */
303 nl_sock_send_seq(struct nl_sock
*sock
, const struct ofpbuf
*msg
,
304 uint32_t nlmsg_seq
, bool wait
)
306 int error
= nl_sock_cow__(sock
);
310 return nl_sock_send__(sock
, msg
, nlmsg_seq
, wait
);
313 /* This stress option is useful for testing that OVS properly tolerates
314 * -ENOBUFS on NetLink sockets. Such errors are unavoidable because they can
315 * occur if the kernel cannot temporarily allocate enough GFP_ATOMIC memory to
316 * reply to a request. They can also occur if messages arrive on a multicast
317 * channel faster than OVS can process them. */
319 netlink_overflow
, "simulate netlink socket receive buffer overflow",
323 nl_sock_recv__(struct nl_sock
*sock
, struct ofpbuf
*buf
, bool wait
)
325 /* We can't accurately predict the size of the data to be received. The
326 * caller is supposed to have allocated enough space in 'buf' to handle the
327 * "typical" case. To handle exceptions, we make available enough space in
328 * 'tail' to allow Netlink messages to be up to 64 kB long (a reasonable
329 * figure since that's the maximum length of a Netlink attribute). */
330 struct nlmsghdr
*nlmsghdr
;
336 assert(buf
->allocated
>= sizeof *nlmsghdr
);
339 iov
[0].iov_base
= buf
->base
;
340 iov
[0].iov_len
= buf
->allocated
;
341 iov
[1].iov_base
= tail
;
342 iov
[1].iov_len
= sizeof tail
;
344 memset(&msg
, 0, sizeof msg
);
349 retval
= recvmsg(sock
->fd
, &msg
, wait
? 0 : MSG_DONTWAIT
);
350 } while (retval
< 0 && errno
== EINTR
);
354 if (error
== ENOBUFS
) {
355 /* Socket receive buffer overflow dropped one or more messages that
356 * the kernel tried to send to us. */
357 COVERAGE_INC(netlink_overflow
);
362 if (msg
.msg_flags
& MSG_TRUNC
) {
363 VLOG_ERR_RL(&rl
, "truncated message (longer than %zu bytes)",
368 nlmsghdr
= buf
->data
;
369 if (retval
< sizeof *nlmsghdr
370 || nlmsghdr
->nlmsg_len
< sizeof *nlmsghdr
371 || nlmsghdr
->nlmsg_len
> retval
) {
372 VLOG_ERR_RL(&rl
, "received invalid nlmsg (%zd bytes < %zu)",
373 retval
, sizeof *nlmsghdr
);
377 if (STRESS(netlink_overflow
)) {
381 buf
->size
= MIN(retval
, buf
->allocated
);
382 if (retval
> buf
->allocated
) {
383 COVERAGE_INC(netlink_recv_jumbo
);
384 ofpbuf_put(buf
, tail
, retval
- buf
->allocated
);
387 log_nlmsg(__func__
, 0, buf
->data
, buf
->size
, sock
->protocol
);
388 COVERAGE_INC(netlink_received
);
393 /* Tries to receive a Netlink message from the kernel on 'sock' into 'buf'. If
394 * 'wait' is true, waits for a message to be ready. Otherwise, fails with
395 * EAGAIN if the 'sock' receive buffer is empty.
397 * The caller must have initialized 'buf' with an allocation of at least
398 * NLMSG_HDRLEN bytes. For best performance, the caller should allocate enough
399 * space for a "typical" message.
401 * On success, returns 0 and replaces 'buf''s previous content by the received
402 * message. This function expands 'buf''s allocated memory, as necessary, to
403 * hold the actual size of the received message.
405 * On failure, returns a positive errno value and clears 'buf' to zero length.
406 * 'buf' retains its previous memory allocation.
408 * Regardless of success or failure, this function resets 'buf''s headroom to
411 nl_sock_recv(struct nl_sock
*sock
, struct ofpbuf
*buf
, bool wait
)
413 int error
= nl_sock_cow__(sock
);
417 return nl_sock_recv__(sock
, buf
, wait
);
421 nl_sock_record_errors__(struct nl_transaction
**transactions
, size_t n
,
426 for (i
= 0; i
< n
; i
++) {
427 struct nl_transaction
*txn
= transactions
[i
];
431 ofpbuf_clear(txn
->reply
);
437 nl_sock_transact_multiple__(struct nl_sock
*sock
,
438 struct nl_transaction
**transactions
, size_t n
,
441 uint64_t tmp_reply_stub
[1024 / 8];
442 struct nl_transaction tmp_txn
;
443 struct ofpbuf tmp_reply
;
446 struct iovec iovs
[MAX_IOVS
];
451 base_seq
= nl_sock_allocate_seq(sock
, n
);
453 for (i
= 0; i
< n
; i
++) {
454 struct nl_transaction
*txn
= transactions
[i
];
455 struct nlmsghdr
*nlmsg
= nl_msg_nlmsghdr(txn
->request
);
457 nlmsg
->nlmsg_len
= txn
->request
->size
;
458 nlmsg
->nlmsg_seq
= base_seq
+ i
;
459 nlmsg
->nlmsg_pid
= sock
->pid
;
461 iovs
[i
].iov_base
= txn
->request
->data
;
462 iovs
[i
].iov_len
= txn
->request
->size
;
465 memset(&msg
, 0, sizeof msg
);
469 error
= sendmsg(sock
->fd
, &msg
, 0) < 0 ? errno
: 0;
470 } while (error
== EINTR
);
472 for (i
= 0; i
< n
; i
++) {
473 struct nl_transaction
*txn
= transactions
[i
];
475 log_nlmsg(__func__
, error
, txn
->request
->data
, txn
->request
->size
,
479 COVERAGE_ADD(netlink_sent
, n
);
486 ofpbuf_use_stub(&tmp_reply
, tmp_reply_stub
, sizeof tmp_reply_stub
);
487 tmp_txn
.request
= NULL
;
488 tmp_txn
.reply
= &tmp_reply
;
491 struct nl_transaction
*buf_txn
, *txn
;
494 /* Find a transaction whose buffer we can use for receiving a reply.
495 * If no such transaction is left, use tmp_txn. */
497 for (i
= 0; i
< n
; i
++) {
498 if (transactions
[i
]->reply
) {
499 buf_txn
= transactions
[i
];
504 /* Receive a reply. */
505 error
= nl_sock_recv__(sock
, buf_txn
->reply
, false);
507 if (error
== EAGAIN
) {
508 nl_sock_record_errors__(transactions
, n
, 0);
515 /* Match the reply up with a transaction. */
516 seq
= nl_msg_nlmsghdr(buf_txn
->reply
)->nlmsg_seq
;
517 if (seq
< base_seq
|| seq
>= base_seq
+ n
) {
518 VLOG_DBG_RL(&rl
, "ignoring unexpected seq %#"PRIx32
, seq
);
522 txn
= transactions
[i
];
524 /* Fill in the results for 'txn'. */
525 if (nl_msg_nlmsgerr(buf_txn
->reply
, &txn
->error
)) {
527 ofpbuf_clear(txn
->reply
);
530 VLOG_DBG_RL(&rl
, "received NAK error=%d (%s)",
531 error
, strerror(txn
->error
));
535 if (txn
->reply
&& txn
!= buf_txn
) {
537 struct ofpbuf
*reply
= buf_txn
->reply
;
538 buf_txn
->reply
= txn
->reply
;
543 /* Fill in the results for transactions before 'txn'. (We have to do
544 * this after the results for 'txn' itself because of the buffer swap
546 nl_sock_record_errors__(transactions
, i
, 0);
550 transactions
+= i
+ 1;
554 ofpbuf_uninit(&tmp_reply
);
559 /* Sends the 'request' member of the 'n' transactions in 'transactions' on
560 * 'sock', in order, and receives responses to all of them. Fills in the
561 * 'error' member of each transaction with 0 if it was successful, otherwise
562 * with a positive errno value. If 'reply' is nonnull, then it will be filled
563 * with the reply if the message receives a detailed reply. In other cases,
564 * i.e. where the request failed or had no reply beyond an indication of
565 * success, 'reply' will be cleared if it is nonnull.
567 * The caller is responsible for destroying each request and reply, and the
568 * transactions array itself.
570 * Before sending each message, this function will finalize nlmsg_len in each
571 * 'request' to match the ofpbuf's size, set nlmsg_pid to 'sock''s pid, and
572 * initialize nlmsg_seq.
574 * Bare Netlink is an unreliable transport protocol. This function layers
575 * reliable delivery and reply semantics on top of bare Netlink. See
576 * nl_sock_transact() for some caveats.
579 nl_sock_transact_multiple(struct nl_sock
*sock
,
580 struct nl_transaction
**transactions
, size_t n
)
589 error
= nl_sock_cow__(sock
);
591 nl_sock_record_errors__(transactions
, n
, error
);
595 /* In theory, every request could have a 64 kB reply. But the default and
596 * maximum socket rcvbuf size with typical Dom0 memory sizes both tend to
597 * be a bit below 128 kB, so that would only allow a single message in a
598 * "batch". So we assume that replies average (at most) 4 kB, which allows
599 * a good deal of batching.
601 * In practice, most of the requests that we batch either have no reply at
602 * all or a brief reply. */
603 max_batch_count
= MAX(sock
->rcvbuf
/ 4096, 1);
604 max_batch_count
= MIN(max_batch_count
, max_iovs
);
610 /* Batch up to 'max_batch_count' transactions. But cap it at about a
611 * page of requests total because big skbuffs are expensive to
612 * allocate in the kernel. */
613 #if defined(PAGESIZE)
614 enum { MAX_BATCH_BYTES
= MAX(1, PAGESIZE
- 512) };
616 enum { MAX_BATCH_BYTES
= 4096 - 512 };
618 bytes
= transactions
[0]->request
->size
;
619 for (count
= 1; count
< n
&& count
< max_batch_count
; count
++) {
620 if (bytes
+ transactions
[count
]->request
->size
> MAX_BATCH_BYTES
) {
623 bytes
+= transactions
[count
]->request
->size
;
626 error
= nl_sock_transact_multiple__(sock
, transactions
, count
, &done
);
627 transactions
+= done
;
630 if (error
== ENOBUFS
) {
631 VLOG_DBG_RL(&rl
, "receive buffer overflow, resending request");
633 VLOG_ERR_RL(&rl
, "transaction error (%s)", strerror(error
));
634 nl_sock_record_errors__(transactions
, n
, error
);
639 /* Sends 'request' to the kernel via 'sock' and waits for a response. If
640 * successful, returns 0. On failure, returns a positive errno value.
642 * If 'replyp' is nonnull, then on success '*replyp' is set to the kernel's
643 * reply, which the caller is responsible for freeing with ofpbuf_delete(), and
644 * on failure '*replyp' is set to NULL. If 'replyp' is null, then the kernel's
645 * reply, if any, is discarded.
647 * Before the message is sent, nlmsg_len in 'request' will be finalized to
648 * match msg->size, nlmsg_pid will be set to 'sock''s pid, and nlmsg_seq will
649 * be initialized, NLM_F_ACK will be set in nlmsg_flags.
651 * The caller is responsible for destroying 'request'.
653 * Bare Netlink is an unreliable transport protocol. This function layers
654 * reliable delivery and reply semantics on top of bare Netlink.
656 * In Netlink, sending a request to the kernel is reliable enough, because the
657 * kernel will tell us if the message cannot be queued (and we will in that
658 * case put it on the transmit queue and wait until it can be delivered).
660 * Receiving the reply is the real problem: if the socket buffer is full when
661 * the kernel tries to send the reply, the reply will be dropped. However, the
662 * kernel sets a flag that a reply has been dropped. The next call to recv
663 * then returns ENOBUFS. We can then re-send the request.
667 * 1. Netlink depends on sequence numbers to match up requests and
668 * replies. The sender of a request supplies a sequence number, and
669 * the reply echos back that sequence number.
671 * This is fine, but (1) some kernel netlink implementations are
672 * broken, in that they fail to echo sequence numbers and (2) this
673 * function will drop packets with non-matching sequence numbers, so
674 * that only a single request can be usefully transacted at a time.
676 * 2. Resending the request causes it to be re-executed, so the request
677 * needs to be idempotent.
680 nl_sock_transact(struct nl_sock
*sock
, const struct ofpbuf
*request
,
681 struct ofpbuf
**replyp
)
683 struct nl_transaction
*transactionp
;
684 struct nl_transaction transaction
;
686 transaction
.request
= (struct ofpbuf
*) request
;
687 transaction
.reply
= replyp
? ofpbuf_new(1024) : NULL
;
688 transactionp
= &transaction
;
690 nl_sock_transact_multiple(sock
, &transactionp
, 1);
693 if (transaction
.error
) {
694 ofpbuf_delete(transaction
.reply
);
697 *replyp
= transaction
.reply
;
701 return transaction
.error
;
704 /* Drain all the messages currently in 'sock''s receive queue. */
706 nl_sock_drain(struct nl_sock
*sock
)
708 int error
= nl_sock_cow__(sock
);
712 return drain_rcvbuf(sock
->fd
);
715 /* The client is attempting some operation on 'sock'. If 'sock' has an ongoing
716 * dump operation, then replace 'sock''s fd with a new socket and hand 'sock''s
717 * old fd over to the dump. */
719 nl_sock_cow__(struct nl_sock
*sock
)
721 struct nl_sock
*copy
;
730 error
= nl_sock_clone(sock
, ©
);
740 sock
->pid
= copy
->pid
;
743 sock
->dump
->sock
= copy
;
749 /* Starts a Netlink "dump" operation, by sending 'request' to the kernel via
750 * 'sock', and initializes 'dump' to reflect the state of the operation.
752 * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will
753 * be set to 'sock''s pid, before the message is sent. NLM_F_DUMP and
754 * NLM_F_ACK will be set in nlmsg_flags.
756 * This Netlink socket library is designed to ensure that the dump is reliable
757 * and that it will not interfere with other operations on 'sock', including
758 * destroying or sending and receiving messages on 'sock'. One corner case is
761 * - If 'sock' has been used to send a request (e.g. with nl_sock_send())
762 * whose response has not yet been received (e.g. with nl_sock_recv()).
763 * This is unusual: usually nl_sock_transact() is used to send a message
764 * and receive its reply all in one go.
766 * This function provides no status indication. An error status for the entire
767 * dump operation is provided when it is completed by calling nl_dump_done().
769 * The caller is responsible for destroying 'request'.
771 * The new 'dump' is independent of 'sock'. 'sock' and 'dump' may be destroyed
775 nl_dump_start(struct nl_dump
*dump
,
776 struct nl_sock
*sock
, const struct ofpbuf
*request
)
778 ofpbuf_init(&dump
->buffer
, 4096);
780 /* 'sock' already has an ongoing dump. Clone the socket because
781 * Netlink only allows one dump at a time. */
782 dump
->status
= nl_sock_clone(sock
, &dump
->sock
);
792 nl_msg_nlmsghdr(request
)->nlmsg_flags
|= NLM_F_DUMP
| NLM_F_ACK
;
793 dump
->status
= nl_sock_send__(sock
, request
, nl_sock_allocate_seq(sock
, 1),
795 dump
->seq
= nl_msg_nlmsghdr(request
)->nlmsg_seq
;
798 /* Helper function for nl_dump_next(). */
800 nl_dump_recv(struct nl_dump
*dump
)
802 struct nlmsghdr
*nlmsghdr
;
805 retval
= nl_sock_recv__(dump
->sock
, &dump
->buffer
, true);
807 return retval
== EINTR
? EAGAIN
: retval
;
810 nlmsghdr
= nl_msg_nlmsghdr(&dump
->buffer
);
811 if (dump
->seq
!= nlmsghdr
->nlmsg_seq
) {
812 VLOG_DBG_RL(&rl
, "ignoring seq %#"PRIx32
" != expected %#"PRIx32
,
813 nlmsghdr
->nlmsg_seq
, dump
->seq
);
817 if (nl_msg_nlmsgerr(&dump
->buffer
, &retval
)) {
818 VLOG_INFO_RL(&rl
, "netlink dump request error (%s)",
820 return retval
&& retval
!= EAGAIN
? retval
: EPROTO
;
826 /* Attempts to retrieve another reply from 'dump', which must have been
827 * initialized with nl_dump_start().
829 * If successful, returns true and points 'reply->data' and 'reply->size' to
830 * the message that was retrieved. The caller must not modify 'reply' (because
831 * it points into the middle of a larger buffer).
833 * On failure, returns false and sets 'reply->data' to NULL and 'reply->size'
834 * to 0. Failure might indicate an actual error or merely the end of replies.
835 * An error status for the entire dump operation is provided when it is
836 * completed by calling nl_dump_done().
839 nl_dump_next(struct nl_dump
*dump
, struct ofpbuf
*reply
)
841 struct nlmsghdr
*nlmsghdr
;
849 while (!dump
->buffer
.size
) {
850 int retval
= nl_dump_recv(dump
);
852 ofpbuf_clear(&dump
->buffer
);
853 if (retval
!= EAGAIN
) {
854 dump
->status
= retval
;
860 nlmsghdr
= nl_msg_next(&dump
->buffer
, reply
);
862 VLOG_WARN_RL(&rl
, "netlink dump reply contains message fragment");
863 dump
->status
= EPROTO
;
865 } else if (nlmsghdr
->nlmsg_type
== NLMSG_DONE
) {
873 /* Completes Netlink dump operation 'dump', which must have been initialized
874 * with nl_dump_start(). Returns 0 if the dump operation was error-free,
875 * otherwise a positive errno value describing the problem. */
877 nl_dump_done(struct nl_dump
*dump
)
879 /* Drain any remaining messages that the client didn't read. Otherwise the
880 * kernel will continue to queue them up and waste buffer space. */
881 while (!dump
->status
) {
883 if (!nl_dump_next(dump
, &reply
)) {
884 assert(dump
->status
);
889 if (dump
->sock
->dump
) {
890 dump
->sock
->dump
= NULL
;
892 nl_sock_destroy(dump
->sock
);
895 ofpbuf_uninit(&dump
->buffer
);
896 return dump
->status
== EOF
? 0 : dump
->status
;
899 /* Causes poll_block() to wake up when any of the specified 'events' (which is
900 * a OR'd combination of POLLIN, POLLOUT, etc.) occur on 'sock'. */
902 nl_sock_wait(const struct nl_sock
*sock
, short int events
)
904 poll_fd_wait(sock
->fd
, events
);
907 /* Returns the underlying fd for 'sock', for use in "poll()"-like operations
908 * that can't use nl_sock_wait().
910 * It's a little tricky to use the returned fd correctly, because nl_sock does
911 * "copy on write" to allow a single nl_sock to be used for notifications,
912 * transactions, and dumps. If 'sock' is used only for notifications and
913 * transactions (and never for dump) then the usage is safe. */
915 nl_sock_fd(const struct nl_sock
*sock
)
920 /* Returns the PID associated with this socket. */
922 nl_sock_pid(const struct nl_sock
*sock
)
930 struct hmap_node hmap_node
;
935 static struct hmap genl_families
= HMAP_INITIALIZER(&genl_families
);
937 static const struct nl_policy family_policy
[CTRL_ATTR_MAX
+ 1] = {
938 [CTRL_ATTR_FAMILY_ID
] = {.type
= NL_A_U16
},
939 [CTRL_ATTR_MCAST_GROUPS
] = {.type
= NL_A_NESTED
, .optional
= true},
942 static struct genl_family
*
943 find_genl_family_by_id(uint16_t id
)
945 struct genl_family
*family
;
947 HMAP_FOR_EACH_IN_BUCKET (family
, hmap_node
, hash_int(id
, 0),
949 if (family
->id
== id
) {
957 define_genl_family(uint16_t id
, const char *name
)
959 struct genl_family
*family
= find_genl_family_by_id(id
);
962 if (!strcmp(family
->name
, name
)) {
967 family
= xmalloc(sizeof *family
);
969 hmap_insert(&genl_families
, &family
->hmap_node
, hash_int(id
, 0));
971 family
->name
= xstrdup(name
);
975 genl_family_to_name(uint16_t id
)
977 if (id
== GENL_ID_CTRL
) {
980 struct genl_family
*family
= find_genl_family_by_id(id
);
981 return family
? family
->name
: "unknown";
986 do_lookup_genl_family(const char *name
, struct nlattr
**attrs
,
987 struct ofpbuf
**replyp
)
989 struct nl_sock
*sock
;
990 struct ofpbuf request
, *reply
;
994 error
= nl_sock_create(NETLINK_GENERIC
, &sock
);
999 ofpbuf_init(&request
, 0);
1000 nl_msg_put_genlmsghdr(&request
, 0, GENL_ID_CTRL
, NLM_F_REQUEST
,
1001 CTRL_CMD_GETFAMILY
, 1);
1002 nl_msg_put_string(&request
, CTRL_ATTR_FAMILY_NAME
, name
);
1003 error
= nl_sock_transact(sock
, &request
, &reply
);
1004 ofpbuf_uninit(&request
);
1006 nl_sock_destroy(sock
);
1010 if (!nl_policy_parse(reply
, NLMSG_HDRLEN
+ GENL_HDRLEN
,
1011 family_policy
, attrs
, ARRAY_SIZE(family_policy
))
1012 || nl_attr_get_u16(attrs
[CTRL_ATTR_FAMILY_ID
]) == 0) {
1013 nl_sock_destroy(sock
);
1014 ofpbuf_delete(reply
);
1018 nl_sock_destroy(sock
);
1023 /* Finds the multicast group called 'group_name' in genl family 'family_name'.
1024 * When successful, writes its result to 'multicast_group' and returns 0.
1025 * Otherwise, clears 'multicast_group' and returns a positive error code.
1027 * Some kernels do not support looking up a multicast group with this function.
1028 * In this case, 'multicast_group' will be populated with 'fallback'. */
1030 nl_lookup_genl_mcgroup(const char *family_name
, const char *group_name
,
1031 unsigned int *multicast_group
, unsigned int fallback
)
1033 struct nlattr
*family_attrs
[ARRAY_SIZE(family_policy
)];
1034 const struct nlattr
*mc
;
1035 struct ofpbuf
*reply
;
1039 *multicast_group
= 0;
1040 error
= do_lookup_genl_family(family_name
, family_attrs
, &reply
);
1045 if (!family_attrs
[CTRL_ATTR_MCAST_GROUPS
]) {
1046 *multicast_group
= fallback
;
1047 VLOG_WARN("%s-%s: has no multicast group, using fallback %d",
1048 family_name
, group_name
, *multicast_group
);
1053 NL_NESTED_FOR_EACH (mc
, left
, family_attrs
[CTRL_ATTR_MCAST_GROUPS
]) {
1054 static const struct nl_policy mc_policy
[] = {
1055 [CTRL_ATTR_MCAST_GRP_ID
] = {.type
= NL_A_U32
},
1056 [CTRL_ATTR_MCAST_GRP_NAME
] = {.type
= NL_A_STRING
},
1059 struct nlattr
*mc_attrs
[ARRAY_SIZE(mc_policy
)];
1060 const char *mc_name
;
1062 if (!nl_parse_nested(mc
, mc_policy
, mc_attrs
, ARRAY_SIZE(mc_policy
))) {
1067 mc_name
= nl_attr_get_string(mc_attrs
[CTRL_ATTR_MCAST_GRP_NAME
]);
1068 if (!strcmp(group_name
, mc_name
)) {
1070 nl_attr_get_u32(mc_attrs
[CTRL_ATTR_MCAST_GRP_ID
]);
1078 ofpbuf_delete(reply
);
1082 /* If '*number' is 0, translates the given Generic Netlink family 'name' to a
1083 * number and stores it in '*number'. If successful, returns 0 and the caller
1084 * may use '*number' as the family number. On failure, returns a positive
1085 * errno value and '*number' caches the errno value. */
1087 nl_lookup_genl_family(const char *name
, int *number
)
1090 struct nlattr
*attrs
[ARRAY_SIZE(family_policy
)];
1091 struct ofpbuf
*reply
;
1094 error
= do_lookup_genl_family(name
, attrs
, &reply
);
1096 *number
= nl_attr_get_u16(attrs
[CTRL_ATTR_FAMILY_ID
]);
1097 define_genl_family(*number
, name
);
1101 ofpbuf_delete(reply
);
1103 assert(*number
!= 0);
1105 return *number
> 0 ? 0 : -*number
;
1109 nl_sock_allocate_seq(struct nl_sock
*sock
, unsigned int n
)
1111 uint32_t seq
= sock
->next_seq
;
1113 sock
->next_seq
+= n
;
1115 /* Make it impossible for the next request for sequence numbers to wrap
1116 * around to 0. Start over with 1 to avoid ever using a sequence number of
1117 * 0, because the kernel uses sequence number 0 for notifications. */
1118 if (sock
->next_seq
>= UINT32_MAX
/ 2) {
1126 nlmsghdr_to_string(const struct nlmsghdr
*h
, int protocol
, struct ds
*ds
)
1132 static const struct nlmsg_flag flags
[] = {
1133 { NLM_F_REQUEST
, "REQUEST" },
1134 { NLM_F_MULTI
, "MULTI" },
1135 { NLM_F_ACK
, "ACK" },
1136 { NLM_F_ECHO
, "ECHO" },
1137 { NLM_F_DUMP
, "DUMP" },
1138 { NLM_F_ROOT
, "ROOT" },
1139 { NLM_F_MATCH
, "MATCH" },
1140 { NLM_F_ATOMIC
, "ATOMIC" },
1142 const struct nlmsg_flag
*flag
;
1143 uint16_t flags_left
;
1145 ds_put_format(ds
, "nl(len:%"PRIu32
", type=%"PRIu16
,
1146 h
->nlmsg_len
, h
->nlmsg_type
);
1147 if (h
->nlmsg_type
== NLMSG_NOOP
) {
1148 ds_put_cstr(ds
, "(no-op)");
1149 } else if (h
->nlmsg_type
== NLMSG_ERROR
) {
1150 ds_put_cstr(ds
, "(error)");
1151 } else if (h
->nlmsg_type
== NLMSG_DONE
) {
1152 ds_put_cstr(ds
, "(done)");
1153 } else if (h
->nlmsg_type
== NLMSG_OVERRUN
) {
1154 ds_put_cstr(ds
, "(overrun)");
1155 } else if (h
->nlmsg_type
< NLMSG_MIN_TYPE
) {
1156 ds_put_cstr(ds
, "(reserved)");
1157 } else if (protocol
== NETLINK_GENERIC
) {
1158 ds_put_format(ds
, "(%s)", genl_family_to_name(h
->nlmsg_type
));
1160 ds_put_cstr(ds
, "(family-defined)");
1162 ds_put_format(ds
, ", flags=%"PRIx16
, h
->nlmsg_flags
);
1163 flags_left
= h
->nlmsg_flags
;
1164 for (flag
= flags
; flag
< &flags
[ARRAY_SIZE(flags
)]; flag
++) {
1165 if ((flags_left
& flag
->bits
) == flag
->bits
) {
1166 ds_put_format(ds
, "[%s]", flag
->name
);
1167 flags_left
&= ~flag
->bits
;
1171 ds_put_format(ds
, "[OTHER:%"PRIx16
"]", flags_left
);
1173 ds_put_format(ds
, ", seq=%"PRIx32
", pid=%"PRIu32
,
1174 h
->nlmsg_seq
, h
->nlmsg_pid
);
1178 nlmsg_to_string(const struct ofpbuf
*buffer
, int protocol
)
1180 struct ds ds
= DS_EMPTY_INITIALIZER
;
1181 const struct nlmsghdr
*h
= ofpbuf_at(buffer
, 0, NLMSG_HDRLEN
);
1183 nlmsghdr_to_string(h
, protocol
, &ds
);
1184 if (h
->nlmsg_type
== NLMSG_ERROR
) {
1185 const struct nlmsgerr
*e
;
1186 e
= ofpbuf_at(buffer
, NLMSG_HDRLEN
,
1187 NLMSG_ALIGN(sizeof(struct nlmsgerr
)));
1189 ds_put_format(&ds
, " error(%d", e
->error
);
1191 ds_put_format(&ds
, "(%s)", strerror(-e
->error
));
1193 ds_put_cstr(&ds
, ", in-reply-to(");
1194 nlmsghdr_to_string(&e
->msg
, protocol
, &ds
);
1195 ds_put_cstr(&ds
, "))");
1197 ds_put_cstr(&ds
, " error(truncated)");
1199 } else if (h
->nlmsg_type
== NLMSG_DONE
) {
1200 int *error
= ofpbuf_at(buffer
, NLMSG_HDRLEN
, sizeof *error
);
1202 ds_put_format(&ds
, " done(%d", *error
);
1204 ds_put_format(&ds
, "(%s)", strerror(-*error
));
1206 ds_put_cstr(&ds
, ")");
1208 ds_put_cstr(&ds
, " done(truncated)");
1210 } else if (protocol
== NETLINK_GENERIC
) {
1211 struct genlmsghdr
*genl
= nl_msg_genlmsghdr(buffer
);
1213 ds_put_format(&ds
, ",genl(cmd=%"PRIu8
",version=%"PRIu8
")",
1214 genl
->cmd
, genl
->version
);
1218 ds_put_cstr(&ds
, "nl(truncated)");
1224 log_nlmsg(const char *function
, int error
,
1225 const void *message
, size_t size
, int protocol
)
1227 struct ofpbuf buffer
;
1230 if (!VLOG_IS_DBG_ENABLED()) {
1234 ofpbuf_use_const(&buffer
, message
, size
);
1235 nlmsg
= nlmsg_to_string(&buffer
, protocol
);
1236 VLOG_DBG_RL(&rl
, "%s (%s): %s", function
, strerror(error
), nlmsg
);