2 * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
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>
26 #include "dynamic-string.h"
30 #include "netlink-protocol.h"
32 #include "poll-loop.h"
33 #include "socket-util.h"
37 VLOG_DEFINE_THIS_MODULE(netlink_socket);
39 COVERAGE_DEFINE(netlink_overflow);
40 COVERAGE_DEFINE(netlink_received);
41 COVERAGE_DEFINE(netlink_recv_retry);
42 COVERAGE_DEFINE(netlink_send);
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 void log_nlmsg(const char *function, int error,
56 const void *message, size_t size, int protocol);
58 /* Netlink sockets. */
69 static int alloc_pid(uint32_t *);
70 static void free_pid(uint32_t);
71 static int nl_sock_cow__(struct nl_sock *);
73 /* Creates a new netlink socket for the given netlink 'protocol'
74 * (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the
75 * new socket if successful, otherwise returns a positive errno value. */
77 nl_sock_create(int protocol, struct nl_sock **sockp)
80 struct sockaddr_nl local, remote;
84 sock = malloc(sizeof *sock);
89 sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
91 VLOG_ERR("fcntl: %s", strerror(errno));
94 sock->protocol = protocol;
95 sock->any_groups = false;
98 retval = alloc_pid(&sock->pid);
103 /* Bind local address as our selected pid. */
104 memset(&local, 0, sizeof local);
105 local.nl_family = AF_NETLINK;
106 local.nl_pid = sock->pid;
107 if (bind(sock->fd, (struct sockaddr *) &local, sizeof local) < 0) {
108 VLOG_ERR("bind(%"PRIu32"): %s", sock->pid, strerror(errno));
112 /* Bind remote address as the kernel (pid 0). */
113 memset(&remote, 0, sizeof remote);
114 remote.nl_family = AF_NETLINK;
116 if (connect(sock->fd, (struct sockaddr *) &remote, sizeof remote) < 0) {
117 VLOG_ERR("connect(0): %s", strerror(errno));
140 /* Creates a new netlink socket for the same protocol as 'src'. Returns 0 and
141 * sets '*sockp' to the new socket if successful, otherwise returns a positive
144 nl_sock_clone(const struct nl_sock *src, struct nl_sock **sockp)
146 return nl_sock_create(src->protocol, sockp);
149 /* Destroys netlink socket 'sock'. */
151 nl_sock_destroy(struct nl_sock *sock)
164 /* Tries to add 'sock' as a listener for 'multicast_group'. Returns 0 if
165 * successful, otherwise a positive errno value.
167 * Multicast group numbers are always positive.
169 * It is not an error to attempt to join a multicast group to which a socket
170 * already belongs. */
172 nl_sock_join_mcgroup(struct nl_sock *sock, unsigned int multicast_group)
174 int error = nl_sock_cow__(sock);
178 if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
179 &multicast_group, sizeof multicast_group) < 0) {
180 VLOG_WARN("could not join multicast group %u (%s)",
181 multicast_group, strerror(errno));
184 sock->any_groups = true;
188 /* Tries to make 'sock' stop listening to 'multicast_group'. Returns 0 if
189 * successful, otherwise a positive errno value.
191 * Multicast group numbers are always positive.
193 * It is not an error to attempt to leave a multicast group to which a socket
196 * On success, reading from 'sock' will still return any messages that were
197 * received on 'multicast_group' before the group was left. */
199 nl_sock_leave_mcgroup(struct nl_sock *sock, unsigned int multicast_group)
202 if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP,
203 &multicast_group, sizeof multicast_group) < 0) {
204 VLOG_WARN("could not leave multicast group %u (%s)",
205 multicast_group, strerror(errno));
212 nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg, bool wait)
214 struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg);
217 nlmsg->nlmsg_len = msg->size;
218 nlmsg->nlmsg_pid = sock->pid;
221 retval = send(sock->fd, msg->data, msg->size, wait ? 0 : MSG_DONTWAIT);
222 error = retval < 0 ? errno : 0;
223 } while (error == EINTR);
224 log_nlmsg(__func__, error, msg->data, msg->size, sock->protocol);
226 COVERAGE_INC(netlink_sent);
231 /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
232 * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, and
233 * nlmsg_pid will be set to 'sock''s pid, before the message is sent.
235 * Returns 0 if successful, otherwise a positive errno value. If
236 * 'wait' is true, then the send will wait until buffer space is ready;
237 * otherwise, returns EAGAIN if the 'sock' send buffer is full. */
239 nl_sock_send(struct nl_sock *sock, const struct ofpbuf *msg, bool wait)
241 int error = nl_sock_cow__(sock);
245 return nl_sock_send__(sock, msg, wait);
248 /* This stress option is useful for testing that OVS properly tolerates
249 * -ENOBUFS on NetLink sockets. Such errors are unavoidable because they can
250 * occur if the kernel cannot temporarily allocate enough GFP_ATOMIC memory to
251 * reply to a request. They can also occur if messages arrive on a multicast
252 * channel faster than OVS can process them. */
254 netlink_overflow, "simulate netlink socket receive buffer overflow",
258 nl_sock_recv__(struct nl_sock *sock, struct ofpbuf **bufp, bool wait)
261 ssize_t bufsize = 2048;
262 ssize_t nbytes, nbytes2;
264 struct nlmsghdr *nlmsghdr;
266 struct msghdr msg = {
276 buf = ofpbuf_new(bufsize);
280 /* Attempt to read the message. We don't know the size of the data
281 * yet, so we take a guess at 2048. If we're wrong, we keep trying
282 * and doubling the buffer size each time.
284 nlmsghdr = ofpbuf_put_uninit(buf, bufsize);
285 iov.iov_base = nlmsghdr;
286 iov.iov_len = bufsize;
288 nbytes = recvmsg(sock->fd, &msg, (wait ? 0 : MSG_DONTWAIT) | MSG_PEEK);
289 } while (nbytes < 0 && errno == EINTR);
294 if (msg.msg_flags & MSG_TRUNC) {
295 COVERAGE_INC(netlink_recv_retry);
297 ofpbuf_reinit(buf, bufsize);
302 /* We successfully read the message, so recv again to clear the queue */
306 nbytes2 = recvmsg(sock->fd, &msg, MSG_DONTWAIT);
307 } while (nbytes2 < 0 && errno == EINTR);
309 if (errno == ENOBUFS) {
310 /* The kernel is notifying us that a message it tried to send to us
311 * was dropped. We have to pass this along to the caller in case
312 * it wants to retry a request. So kill the buffer, which we can
313 * re-read next time. */
314 COVERAGE_INC(netlink_overflow);
318 VLOG_ERR_RL(&rl, "failed to remove nlmsg from socket: %s\n",
322 if (nbytes < sizeof *nlmsghdr
323 || nlmsghdr->nlmsg_len < sizeof *nlmsghdr
324 || nlmsghdr->nlmsg_len > nbytes) {
325 VLOG_ERR_RL(&rl, "received invalid nlmsg (%zd bytes < %d)",
326 bufsize, NLMSG_HDRLEN);
331 if (STRESS(netlink_overflow)) {
337 log_nlmsg(__func__, 0, buf->data, buf->size, sock->protocol);
338 COVERAGE_INC(netlink_received);
343 /* Tries to receive a netlink message from the kernel on 'sock'. If
344 * successful, stores the received message into '*bufp' and returns 0. The
345 * caller is responsible for destroying the message with ofpbuf_delete(). On
346 * failure, returns a positive errno value and stores a null pointer into
349 * If 'wait' is true, nl_sock_recv waits for a message to be ready; otherwise,
350 * returns EAGAIN if the 'sock' receive buffer is empty. */
352 nl_sock_recv(struct nl_sock *sock, struct ofpbuf **bufp, bool wait)
354 int error = nl_sock_cow__(sock);
358 return nl_sock_recv__(sock, bufp, wait);
361 /* Sends 'request' to the kernel via 'sock' and waits for a response. If
362 * successful, returns 0. On failure, returns a positive errno value.
364 * If 'replyp' is nonnull, then on success '*replyp' is set to the kernel's
365 * reply, which the caller is responsible for freeing with ofpbuf_delete(), and
366 * on failure '*replyp' is set to NULL. If 'replyp' is null, then the kernel's
367 * reply, if any, is discarded.
369 * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will
370 * be set to 'sock''s pid, before the message is sent. NLM_F_ACK will be set
373 * The caller is responsible for destroying 'request'.
375 * Bare Netlink is an unreliable transport protocol. This function layers
376 * reliable delivery and reply semantics on top of bare Netlink.
378 * In Netlink, sending a request to the kernel is reliable enough, because the
379 * kernel will tell us if the message cannot be queued (and we will in that
380 * case put it on the transmit queue and wait until it can be delivered).
382 * Receiving the reply is the real problem: if the socket buffer is full when
383 * the kernel tries to send the reply, the reply will be dropped. However, the
384 * kernel sets a flag that a reply has been dropped. The next call to recv
385 * then returns ENOBUFS. We can then re-send the request.
389 * 1. Netlink depends on sequence numbers to match up requests and
390 * replies. The sender of a request supplies a sequence number, and
391 * the reply echos back that sequence number.
393 * This is fine, but (1) some kernel netlink implementations are
394 * broken, in that they fail to echo sequence numbers and (2) this
395 * function will drop packets with non-matching sequence numbers, so
396 * that only a single request can be usefully transacted at a time.
398 * 2. Resending the request causes it to be re-executed, so the request
399 * needs to be idempotent.
402 nl_sock_transact(struct nl_sock *sock,
403 const struct ofpbuf *request, struct ofpbuf **replyp)
405 uint32_t seq = nl_msg_nlmsghdr(request)->nlmsg_seq;
406 struct nlmsghdr *nlmsghdr;
407 struct ofpbuf *reply;
414 /* Ensure that we get a reply even if this message doesn't ordinarily call
416 nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_ACK;
419 retval = nl_sock_send(sock, request, true);
425 retval = nl_sock_recv(sock, &reply, true);
427 if (retval == ENOBUFS) {
428 COVERAGE_INC(netlink_overflow);
429 VLOG_DBG_RL(&rl, "receive buffer overflow, resending request");
435 nlmsghdr = nl_msg_nlmsghdr(reply);
436 if (seq != nlmsghdr->nlmsg_seq) {
437 VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32,
438 nl_msg_nlmsghdr(reply)->nlmsg_seq, seq);
439 ofpbuf_delete(reply);
443 /* If the reply is an error, discard the reply and return the error code.
445 * Except: if the reply is just an acknowledgement (error code of 0), and
446 * the caller is interested in the reply (replyp != NULL), pass the reply
447 * up to the caller. Otherwise the caller will get a return value of 0
448 * and null '*replyp', which makes unwary callers likely to segfault. */
449 if (nl_msg_nlmsgerr(reply, &retval) && (retval || !replyp)) {
450 ofpbuf_delete(reply);
452 VLOG_DBG_RL(&rl, "received NAK error=%d (%s)",
453 retval, strerror(retval));
455 return retval != EAGAIN ? retval : EPROTO;
461 ofpbuf_delete(reply);
466 /* Drain all the messages currently in 'sock''s receive queue. */
468 nl_sock_drain(struct nl_sock *sock)
470 int error = nl_sock_cow__(sock);
474 return drain_rcvbuf(sock->fd);
477 /* The client is attempting some operation on 'sock'. If 'sock' has an ongoing
478 * dump operation, then replace 'sock''s fd with a new socket and hand 'sock''s
479 * old fd over to the dump. */
481 nl_sock_cow__(struct nl_sock *sock)
483 struct nl_sock *copy;
492 error = nl_sock_clone(sock, ©);
502 sock->pid = copy->pid;
505 sock->dump->sock = copy;
511 /* Starts a Netlink "dump" operation, by sending 'request' to the kernel via
512 * 'sock', and initializes 'dump' to reflect the state of the operation.
514 * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will
515 * be set to 'sock''s pid, before the message is sent. NLM_F_DUMP and
516 * NLM_F_ACK will be set in nlmsg_flags.
518 * This Netlink socket library is designed to ensure that the dump is reliable
519 * and that it will not interfere with other operations on 'sock', including
520 * destroying or sending and receiving messages on 'sock'. One corner case is
523 * - If 'sock' has been used to send a request (e.g. with nl_sock_send())
524 * whose response has not yet been received (e.g. with nl_sock_recv()).
525 * This is unusual: usually nl_sock_transact() is used to send a message
526 * and receive its reply all in one go.
528 * This function provides no status indication. An error status for the entire
529 * dump operation is provided when it is completed by calling nl_dump_done().
531 * The caller is responsible for destroying 'request'.
533 * The new 'dump' is independent of 'sock'. 'sock' and 'dump' may be destroyed
537 nl_dump_start(struct nl_dump *dump,
538 struct nl_sock *sock, const struct ofpbuf *request)
540 struct nlmsghdr *nlmsghdr = nl_msg_nlmsghdr(request);
541 nlmsghdr->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK;
542 dump->seq = nlmsghdr->nlmsg_seq;
544 if (sock->any_groups || sock->dump) {
545 /* 'sock' might belong to some multicast group, or it already has an
546 * onoging dump. Clone the socket to avoid possibly intermixing
547 * multicast messages or previous dump results with our results. */
548 dump->status = nl_sock_clone(sock, &dump->sock);
557 dump->status = nl_sock_send__(sock, request, true);
560 /* Helper function for nl_dump_next(). */
562 nl_dump_recv(struct nl_dump *dump, struct ofpbuf **bufferp)
564 struct nlmsghdr *nlmsghdr;
565 struct ofpbuf *buffer;
568 retval = nl_sock_recv__(dump->sock, bufferp, true);
570 return retval == EINTR ? EAGAIN : retval;
574 nlmsghdr = nl_msg_nlmsghdr(buffer);
575 if (dump->seq != nlmsghdr->nlmsg_seq) {
576 VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32,
577 nlmsghdr->nlmsg_seq, dump->seq);
581 if (nl_msg_nlmsgerr(buffer, &retval)) {
582 VLOG_INFO_RL(&rl, "netlink dump request error (%s)",
584 return retval && retval != EAGAIN ? retval : EPROTO;
590 /* Attempts to retrieve another reply from 'dump', which must have been
591 * initialized with nl_dump_start().
593 * If successful, returns true and points 'reply->data' and 'reply->size' to
594 * the message that was retrieved. The caller must not modify 'reply' (because
595 * it points into the middle of a larger buffer).
597 * On failure, returns false and sets 'reply->data' to NULL and 'reply->size'
598 * to 0. Failure might indicate an actual error or merely the end of replies.
599 * An error status for the entire dump operation is provided when it is
600 * completed by calling nl_dump_done().
603 nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply)
605 struct nlmsghdr *nlmsghdr;
613 if (dump->buffer && !dump->buffer->size) {
614 ofpbuf_delete(dump->buffer);
617 while (!dump->buffer) {
618 int retval = nl_dump_recv(dump, &dump->buffer);
620 ofpbuf_delete(dump->buffer);
622 if (retval != EAGAIN) {
623 dump->status = retval;
629 nlmsghdr = nl_msg_next(dump->buffer, reply);
631 VLOG_WARN_RL(&rl, "netlink dump reply contains message fragment");
632 dump->status = EPROTO;
634 } else if (nlmsghdr->nlmsg_type == NLMSG_DONE) {
642 /* Completes Netlink dump operation 'dump', which must have been initialized
643 * with nl_dump_start(). Returns 0 if the dump operation was error-free,
644 * otherwise a positive errno value describing the problem. */
646 nl_dump_done(struct nl_dump *dump)
648 /* Drain any remaining messages that the client didn't read. Otherwise the
649 * kernel will continue to queue them up and waste buffer space. */
650 while (!dump->status) {
652 if (!nl_dump_next(dump, &reply)) {
653 assert(dump->status);
658 if (dump->sock->dump) {
659 dump->sock->dump = NULL;
661 nl_sock_destroy(dump->sock);
664 ofpbuf_delete(dump->buffer);
665 return dump->status == EOF ? 0 : dump->status;
668 /* Causes poll_block() to wake up when any of the specified 'events' (which is
669 * a OR'd combination of POLLIN, POLLOUT, etc.) occur on 'sock'. */
671 nl_sock_wait(const struct nl_sock *sock, short int events)
673 poll_fd_wait(sock->fd, events);
679 struct hmap_node hmap_node;
684 static struct hmap genl_families = HMAP_INITIALIZER(&genl_families);
686 static const struct nl_policy family_policy[CTRL_ATTR_MAX + 1] = {
687 [CTRL_ATTR_FAMILY_ID] = {.type = NL_A_U16},
690 static struct genl_family *
691 find_genl_family_by_id(uint16_t id)
693 struct genl_family *family;
695 HMAP_FOR_EACH_IN_BUCKET (family, hmap_node, hash_int(id, 0),
697 if (family->id == id) {
705 define_genl_family(uint16_t id, const char *name)
707 struct genl_family *family = find_genl_family_by_id(id);
710 if (!strcmp(family->name, name)) {
715 family = xmalloc(sizeof *family);
717 hmap_insert(&genl_families, &family->hmap_node, hash_int(id, 0));
719 family->name = xstrdup(name);
723 genl_family_to_name(uint16_t id)
725 if (id == GENL_ID_CTRL) {
728 struct genl_family *family = find_genl_family_by_id(id);
729 return family ? family->name : "unknown";
733 static int do_lookup_genl_family(const char *name)
735 struct nl_sock *sock;
736 struct ofpbuf request, *reply;
737 struct nlattr *attrs[ARRAY_SIZE(family_policy)];
740 retval = nl_sock_create(NETLINK_GENERIC, &sock);
745 ofpbuf_init(&request, 0);
746 nl_msg_put_genlmsghdr(&request, 0, GENL_ID_CTRL, NLM_F_REQUEST,
747 CTRL_CMD_GETFAMILY, 1);
748 nl_msg_put_string(&request, CTRL_ATTR_FAMILY_NAME, name);
749 retval = nl_sock_transact(sock, &request, &reply);
750 ofpbuf_uninit(&request);
752 nl_sock_destroy(sock);
756 if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN,
757 family_policy, attrs, ARRAY_SIZE(family_policy))) {
758 nl_sock_destroy(sock);
759 ofpbuf_delete(reply);
763 retval = nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]);
767 define_genl_family(retval, name);
769 nl_sock_destroy(sock);
770 ofpbuf_delete(reply);
775 /* If '*number' is 0, translates the given Generic Netlink family 'name' to a
776 * number and stores it in '*number'. If successful, returns 0 and the caller
777 * may use '*number' as the family number. On failure, returns a positive
778 * errno value and '*number' caches the errno value. */
780 nl_lookup_genl_family(const char *name, int *number)
783 *number = do_lookup_genl_family(name);
784 assert(*number != 0);
786 return *number > 0 ? 0 : -*number;
791 * Every Netlink socket must be bound to a unique 32-bit PID. By convention,
792 * programs that have a single Netlink socket use their Unix process ID as PID,
793 * and programs with multiple Netlink sockets add a unique per-socket
794 * identifier in the bits above the Unix process ID.
796 * The kernel has Netlink PID 0.
799 /* Parameters for how many bits in the PID should come from the Unix process ID
800 * and how many unique per-socket. */
801 #define SOCKET_BITS 10
802 #define MAX_SOCKETS (1u << SOCKET_BITS)
804 #define PROCESS_BITS (32 - SOCKET_BITS)
805 #define MAX_PROCESSES (1u << PROCESS_BITS)
806 #define PROCESS_MASK ((uint32_t) (MAX_PROCESSES - 1))
808 /* Bit vector of unused socket identifiers. */
809 static uint32_t avail_sockets[ROUND_UP(MAX_SOCKETS, 32)];
811 /* Allocates and returns a new Netlink PID. */
813 alloc_pid(uint32_t *pid)
817 for (i = 0; i < MAX_SOCKETS; i++) {
818 if ((avail_sockets[i / 32] & (1u << (i % 32))) == 0) {
819 avail_sockets[i / 32] |= 1u << (i % 32);
820 *pid = (getpid() & PROCESS_MASK) | (i << PROCESS_BITS);
824 VLOG_ERR("netlink pid space exhausted");
828 /* Makes the specified 'pid' available for reuse. */
830 free_pid(uint32_t pid)
832 int sock = pid >> PROCESS_BITS;
833 assert(avail_sockets[sock / 32] & (1u << (sock % 32)));
834 avail_sockets[sock / 32] &= ~(1u << (sock % 32));
838 nlmsghdr_to_string(const struct nlmsghdr *h, int protocol, struct ds *ds)
844 static const struct nlmsg_flag flags[] = {
845 { NLM_F_REQUEST, "REQUEST" },
846 { NLM_F_MULTI, "MULTI" },
847 { NLM_F_ACK, "ACK" },
848 { NLM_F_ECHO, "ECHO" },
849 { NLM_F_DUMP, "DUMP" },
850 { NLM_F_ROOT, "ROOT" },
851 { NLM_F_MATCH, "MATCH" },
852 { NLM_F_ATOMIC, "ATOMIC" },
854 const struct nlmsg_flag *flag;
857 ds_put_format(ds, "nl(len:%"PRIu32", type=%"PRIu16,
858 h->nlmsg_len, h->nlmsg_type);
859 if (h->nlmsg_type == NLMSG_NOOP) {
860 ds_put_cstr(ds, "(no-op)");
861 } else if (h->nlmsg_type == NLMSG_ERROR) {
862 ds_put_cstr(ds, "(error)");
863 } else if (h->nlmsg_type == NLMSG_DONE) {
864 ds_put_cstr(ds, "(done)");
865 } else if (h->nlmsg_type == NLMSG_OVERRUN) {
866 ds_put_cstr(ds, "(overrun)");
867 } else if (h->nlmsg_type < NLMSG_MIN_TYPE) {
868 ds_put_cstr(ds, "(reserved)");
869 } else if (protocol == NETLINK_GENERIC) {
870 ds_put_format(ds, "(%s)", genl_family_to_name(h->nlmsg_type));
872 ds_put_cstr(ds, "(family-defined)");
874 ds_put_format(ds, ", flags=%"PRIx16, h->nlmsg_flags);
875 flags_left = h->nlmsg_flags;
876 for (flag = flags; flag < &flags[ARRAY_SIZE(flags)]; flag++) {
877 if ((flags_left & flag->bits) == flag->bits) {
878 ds_put_format(ds, "[%s]", flag->name);
879 flags_left &= ~flag->bits;
883 ds_put_format(ds, "[OTHER:%"PRIx16"]", flags_left);
885 ds_put_format(ds, ", seq=%"PRIx32", pid=%"PRIu32"(%d:%d))",
886 h->nlmsg_seq, h->nlmsg_pid,
887 (int) (h->nlmsg_pid & PROCESS_MASK),
888 (int) (h->nlmsg_pid >> PROCESS_BITS));
892 nlmsg_to_string(const struct ofpbuf *buffer, int protocol)
894 struct ds ds = DS_EMPTY_INITIALIZER;
895 const struct nlmsghdr *h = ofpbuf_at(buffer, 0, NLMSG_HDRLEN);
897 nlmsghdr_to_string(h, protocol, &ds);
898 if (h->nlmsg_type == NLMSG_ERROR) {
899 const struct nlmsgerr *e;
900 e = ofpbuf_at(buffer, NLMSG_HDRLEN,
901 NLMSG_ALIGN(sizeof(struct nlmsgerr)));
903 ds_put_format(&ds, " error(%d", e->error);
905 ds_put_format(&ds, "(%s)", strerror(-e->error));
907 ds_put_cstr(&ds, ", in-reply-to(");
908 nlmsghdr_to_string(&e->msg, protocol, &ds);
909 ds_put_cstr(&ds, "))");
911 ds_put_cstr(&ds, " error(truncated)");
913 } else if (h->nlmsg_type == NLMSG_DONE) {
914 int *error = ofpbuf_at(buffer, NLMSG_HDRLEN, sizeof *error);
916 ds_put_format(&ds, " done(%d", *error);
918 ds_put_format(&ds, "(%s)", strerror(-*error));
920 ds_put_cstr(&ds, ")");
922 ds_put_cstr(&ds, " done(truncated)");
924 } else if (protocol == NETLINK_GENERIC) {
925 struct genlmsghdr *genl = nl_msg_genlmsghdr(buffer);
927 ds_put_format(&ds, ",genl(cmd=%"PRIu8",version=%"PRIu8")",
928 genl->cmd, genl->version);
932 ds_put_cstr(&ds, "nl(truncated)");
938 log_nlmsg(const char *function, int error,
939 const void *message, size_t size, int protocol)
941 struct ofpbuf buffer;
944 if (!VLOG_IS_DBG_ENABLED()) {
948 ofpbuf_use_const(&buffer, message, size);
949 nlmsg = nlmsg_to_string(&buffer, protocol);
950 VLOG_DBG_RL(&rl, "%s (%s): %s", function, strerror(error), nlmsg);