/openvswitch/lib/netlink-socket.c
C | 1219 lines | 841 code | 139 blank | 239 comment | 165 complexity | 3913d49b11d2d3228717b73c7d9e9c88 MD5 | raw file
Possible License(s): BSD-3-Clause, GPL-3.0, LGPL-3.0, Apache-2.0, LGPL-2.1, GPL-2.0, MIT
- /*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at:
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #include <config.h>
- #include "netlink-socket.h"
- #include <errno.h>
- #include <inttypes.h>
- #include <stdlib.h>
- #include <sys/types.h>
- #include <sys/uio.h>
- #include <unistd.h>
- #include "coverage.h"
- #include "dynamic-string.h"
- #include "hash.h"
- #include "hmap.h"
- #include "netlink.h"
- #include "netlink-protocol.h"
- #include "ofpbuf.h"
- #include "ovs-thread.h"
- #include "poll-loop.h"
- #include "socket-util.h"
- #include "util.h"
- #include "vlog.h"
- VLOG_DEFINE_THIS_MODULE(netlink_socket);
- COVERAGE_DEFINE(netlink_overflow);
- COVERAGE_DEFINE(netlink_received);
- COVERAGE_DEFINE(netlink_recv_jumbo);
- COVERAGE_DEFINE(netlink_send);
- COVERAGE_DEFINE(netlink_sent);
- /* Linux header file confusion causes this to be undefined. */
- #ifndef SOL_NETLINK
- #define SOL_NETLINK 270
- #endif
- /* A single (bad) Netlink message can in theory dump out many, many log
- * messages, so the burst size is set quite high here to avoid missing useful
- * information. Also, at high logging levels we log *all* Netlink messages. */
- static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 600);
- static uint32_t nl_sock_allocate_seq(struct nl_sock *, unsigned int n);
- static void log_nlmsg(const char *function, int error,
- const void *message, size_t size, int protocol);
- /* Netlink sockets. */
- struct nl_sock {
- int fd;
- uint32_t next_seq;
- uint32_t pid;
- int protocol;
- unsigned int rcvbuf; /* Receive buffer size (SO_RCVBUF). */
- };
- /* Compile-time limit on iovecs, so that we can allocate a maximum-size array
- * of iovecs on the stack. */
- #define MAX_IOVS 128
- /* Maximum number of iovecs that may be passed to sendmsg, capped at a
- * minimum of _XOPEN_IOV_MAX (16) and a maximum of MAX_IOVS.
- *
- * Initialized by nl_sock_create(). */
- static int max_iovs;
- static int nl_pool_alloc(int protocol, struct nl_sock **sockp);
- static void nl_pool_release(struct nl_sock *);
- /* Creates a new netlink socket for the given netlink 'protocol'
- * (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the
- * new socket if successful, otherwise returns a positive errno value. */
- int
- nl_sock_create(int protocol, struct nl_sock **sockp)
- {
- static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
- struct nl_sock *sock;
- struct sockaddr_nl local, remote;
- socklen_t local_size;
- int rcvbuf;
- int retval = 0;
- if (ovsthread_once_start(&once)) {
- int save_errno = errno;
- errno = 0;
- max_iovs = sysconf(_SC_UIO_MAXIOV);
- if (max_iovs < _XOPEN_IOV_MAX) {
- if (max_iovs == -1 && errno) {
- VLOG_WARN("sysconf(_SC_UIO_MAXIOV): %s", ovs_strerror(errno));
- }
- max_iovs = _XOPEN_IOV_MAX;
- } else if (max_iovs > MAX_IOVS) {
- max_iovs = MAX_IOVS;
- }
- errno = save_errno;
- ovsthread_once_done(&once);
- }
- *sockp = NULL;
- sock = xmalloc(sizeof *sock);
- sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
- if (sock->fd < 0) {
- VLOG_ERR("fcntl: %s", ovs_strerror(errno));
- goto error;
- }
- sock->protocol = protocol;
- sock->next_seq = 1;
- rcvbuf = 1024 * 1024;
- if (setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUFFORCE,
- &rcvbuf, sizeof rcvbuf)) {
- /* Only root can use SO_RCVBUFFORCE. Everyone else gets EPERM.
- * Warn only if the failure is therefore unexpected. */
- if (errno != EPERM) {
- VLOG_WARN_RL(&rl, "setting %d-byte socket receive buffer failed "
- "(%s)", rcvbuf, ovs_strerror(errno));
- }
- }
- retval = get_socket_rcvbuf(sock->fd);
- if (retval < 0) {
- retval = -retval;
- goto error;
- }
- sock->rcvbuf = retval;
- /* Connect to kernel (pid 0) as remote address. */
- memset(&remote, 0, sizeof remote);
- remote.nl_family = AF_NETLINK;
- remote.nl_pid = 0;
- if (connect(sock->fd, (struct sockaddr *) &remote, sizeof remote) < 0) {
- VLOG_ERR("connect(0): %s", ovs_strerror(errno));
- goto error;
- }
- /* Obtain pid assigned by kernel. */
- local_size = sizeof local;
- if (getsockname(sock->fd, (struct sockaddr *) &local, &local_size) < 0) {
- VLOG_ERR("getsockname: %s", ovs_strerror(errno));
- goto error;
- }
- if (local_size < sizeof local || local.nl_family != AF_NETLINK) {
- VLOG_ERR("getsockname returned bad Netlink name");
- retval = EINVAL;
- goto error;
- }
- sock->pid = local.nl_pid;
- *sockp = sock;
- return 0;
- error:
- if (retval == 0) {
- retval = errno;
- if (retval == 0) {
- retval = EINVAL;
- }
- }
- if (sock->fd >= 0) {
- close(sock->fd);
- }
- free(sock);
- return retval;
- }
- /* Creates a new netlink socket for the same protocol as 'src'. Returns 0 and
- * sets '*sockp' to the new socket if successful, otherwise returns a positive
- * errno value. */
- int
- nl_sock_clone(const struct nl_sock *src, struct nl_sock **sockp)
- {
- return nl_sock_create(src->protocol, sockp);
- }
- /* Destroys netlink socket 'sock'. */
- void
- nl_sock_destroy(struct nl_sock *sock)
- {
- if (sock) {
- close(sock->fd);
- free(sock);
- }
- }
- /* Tries to add 'sock' as a listener for 'multicast_group'. Returns 0 if
- * successful, otherwise a positive errno value.
- *
- * A socket that is subscribed to a multicast group that receives asynchronous
- * notifications must not be used for Netlink transactions or dumps, because
- * transactions and dumps can cause notifications to be lost.
- *
- * Multicast group numbers are always positive.
- *
- * It is not an error to attempt to join a multicast group to which a socket
- * already belongs. */
- int
- nl_sock_join_mcgroup(struct nl_sock *sock, unsigned int multicast_group)
- {
- if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
- &multicast_group, sizeof multicast_group) < 0) {
- VLOG_WARN("could not join multicast group %u (%s)",
- multicast_group, ovs_strerror(errno));
- return errno;
- }
- return 0;
- }
- /* Tries to make 'sock' stop listening to 'multicast_group'. Returns 0 if
- * successful, otherwise a positive errno value.
- *
- * Multicast group numbers are always positive.
- *
- * It is not an error to attempt to leave a multicast group to which a socket
- * does not belong.
- *
- * On success, reading from 'sock' will still return any messages that were
- * received on 'multicast_group' before the group was left. */
- int
- nl_sock_leave_mcgroup(struct nl_sock *sock, unsigned int multicast_group)
- {
- if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP,
- &multicast_group, sizeof multicast_group) < 0) {
- VLOG_WARN("could not leave multicast group %u (%s)",
- multicast_group, ovs_strerror(errno));
- return errno;
- }
- return 0;
- }
- static int
- nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg,
- uint32_t nlmsg_seq, bool wait)
- {
- struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg);
- int error;
- nlmsg->nlmsg_len = msg->size;
- nlmsg->nlmsg_seq = nlmsg_seq;
- nlmsg->nlmsg_pid = sock->pid;
- do {
- int retval;
- retval = send(sock->fd, msg->data, msg->size, wait ? 0 : MSG_DONTWAIT);
- error = retval < 0 ? errno : 0;
- } while (error == EINTR);
- log_nlmsg(__func__, error, msg->data, msg->size, sock->protocol);
- if (!error) {
- COVERAGE_INC(netlink_sent);
- }
- return error;
- }
- /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
- * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
- * will be set to 'sock''s pid, and nlmsg_seq will be initialized to a fresh
- * sequence number, before the message is sent.
- *
- * Returns 0 if successful, otherwise a positive errno value. If
- * 'wait' is true, then the send will wait until buffer space is ready;
- * otherwise, returns EAGAIN if the 'sock' send buffer is full. */
- int
- nl_sock_send(struct nl_sock *sock, const struct ofpbuf *msg, bool wait)
- {
- return nl_sock_send_seq(sock, msg, nl_sock_allocate_seq(sock, 1), wait);
- }
- /* Tries to send 'msg', which must contain a Netlink message, to the kernel on
- * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
- * will be set to 'sock''s pid, and nlmsg_seq will be initialized to
- * 'nlmsg_seq', before the message is sent.
- *
- * Returns 0 if successful, otherwise a positive errno value. If
- * 'wait' is true, then the send will wait until buffer space is ready;
- * otherwise, returns EAGAIN if the 'sock' send buffer is full.
- *
- * This function is suitable for sending a reply to a request that was received
- * with sequence number 'nlmsg_seq'. Otherwise, use nl_sock_send() instead. */
- int
- nl_sock_send_seq(struct nl_sock *sock, const struct ofpbuf *msg,
- uint32_t nlmsg_seq, bool wait)
- {
- return nl_sock_send__(sock, msg, nlmsg_seq, wait);
- }
- static int
- nl_sock_recv__(struct nl_sock *sock, struct ofpbuf *buf, bool wait)
- {
- /* We can't accurately predict the size of the data to be received. The
- * caller is supposed to have allocated enough space in 'buf' to handle the
- * "typical" case. To handle exceptions, we make available enough space in
- * 'tail' to allow Netlink messages to be up to 64 kB long (a reasonable
- * figure since that's the maximum length of a Netlink attribute). */
- struct nlmsghdr *nlmsghdr;
- uint8_t tail[65536];
- struct iovec iov[2];
- struct msghdr msg;
- ssize_t retval;
- ovs_assert(buf->allocated >= sizeof *nlmsghdr);
- ofpbuf_clear(buf);
- iov[0].iov_base = buf->base;
- iov[0].iov_len = buf->allocated;
- iov[1].iov_base = tail;
- iov[1].iov_len = sizeof tail;
- memset(&msg, 0, sizeof msg);
- msg.msg_iov = iov;
- msg.msg_iovlen = 2;
- do {
- retval = recvmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
- } while (retval < 0 && errno == EINTR);
- if (retval < 0) {
- int error = errno;
- if (error == ENOBUFS) {
- /* Socket receive buffer overflow dropped one or more messages that
- * the kernel tried to send to us. */
- COVERAGE_INC(netlink_overflow);
- }
- return error;
- }
- if (msg.msg_flags & MSG_TRUNC) {
- VLOG_ERR_RL(&rl, "truncated message (longer than %zu bytes)",
- sizeof tail);
- return E2BIG;
- }
- nlmsghdr = buf->data;
- if (retval < sizeof *nlmsghdr
- || nlmsghdr->nlmsg_len < sizeof *nlmsghdr
- || nlmsghdr->nlmsg_len > retval) {
- VLOG_ERR_RL(&rl, "received invalid nlmsg (%zd bytes < %zu)",
- retval, sizeof *nlmsghdr);
- return EPROTO;
- }
- buf->size = MIN(retval, buf->allocated);
- if (retval > buf->allocated) {
- COVERAGE_INC(netlink_recv_jumbo);
- ofpbuf_put(buf, tail, retval - buf->allocated);
- }
- log_nlmsg(__func__, 0, buf->data, buf->size, sock->protocol);
- COVERAGE_INC(netlink_received);
- return 0;
- }
- /* Tries to receive a Netlink message from the kernel on 'sock' into 'buf'. If
- * 'wait' is true, waits for a message to be ready. Otherwise, fails with
- * EAGAIN if the 'sock' receive buffer is empty.
- *
- * The caller must have initialized 'buf' with an allocation of at least
- * NLMSG_HDRLEN bytes. For best performance, the caller should allocate enough
- * space for a "typical" message.
- *
- * On success, returns 0 and replaces 'buf''s previous content by the received
- * message. This function expands 'buf''s allocated memory, as necessary, to
- * hold the actual size of the received message.
- *
- * On failure, returns a positive errno value and clears 'buf' to zero length.
- * 'buf' retains its previous memory allocation.
- *
- * Regardless of success or failure, this function resets 'buf''s headroom to
- * 0. */
- int
- nl_sock_recv(struct nl_sock *sock, struct ofpbuf *buf, bool wait)
- {
- return nl_sock_recv__(sock, buf, wait);
- }
- static void
- nl_sock_record_errors__(struct nl_transaction **transactions, size_t n,
- int error)
- {
- size_t i;
- for (i = 0; i < n; i++) {
- struct nl_transaction *txn = transactions[i];
- txn->error = error;
- if (txn->reply) {
- ofpbuf_clear(txn->reply);
- }
- }
- }
- static int
- nl_sock_transact_multiple__(struct nl_sock *sock,
- struct nl_transaction **transactions, size_t n,
- size_t *done)
- {
- uint64_t tmp_reply_stub[1024 / 8];
- struct nl_transaction tmp_txn;
- struct ofpbuf tmp_reply;
- uint32_t base_seq;
- struct iovec iovs[MAX_IOVS];
- struct msghdr msg;
- int error;
- int i;
- base_seq = nl_sock_allocate_seq(sock, n);
- *done = 0;
- for (i = 0; i < n; i++) {
- struct nl_transaction *txn = transactions[i];
- struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(txn->request);
- nlmsg->nlmsg_len = txn->request->size;
- nlmsg->nlmsg_seq = base_seq + i;
- nlmsg->nlmsg_pid = sock->pid;
- iovs[i].iov_base = txn->request->data;
- iovs[i].iov_len = txn->request->size;
- }
- memset(&msg, 0, sizeof msg);
- msg.msg_iov = iovs;
- msg.msg_iovlen = n;
- do {
- error = sendmsg(sock->fd, &msg, 0) < 0 ? errno : 0;
- } while (error == EINTR);
- for (i = 0; i < n; i++) {
- struct nl_transaction *txn = transactions[i];
- log_nlmsg(__func__, error, txn->request->data, txn->request->size,
- sock->protocol);
- }
- if (!error) {
- COVERAGE_ADD(netlink_sent, n);
- }
- if (error) {
- return error;
- }
- ofpbuf_use_stub(&tmp_reply, tmp_reply_stub, sizeof tmp_reply_stub);
- tmp_txn.request = NULL;
- tmp_txn.reply = &tmp_reply;
- tmp_txn.error = 0;
- while (n > 0) {
- struct nl_transaction *buf_txn, *txn;
- uint32_t seq;
- /* Find a transaction whose buffer we can use for receiving a reply.
- * If no such transaction is left, use tmp_txn. */
- buf_txn = &tmp_txn;
- for (i = 0; i < n; i++) {
- if (transactions[i]->reply) {
- buf_txn = transactions[i];
- break;
- }
- }
- /* Receive a reply. */
- error = nl_sock_recv__(sock, buf_txn->reply, false);
- if (error) {
- if (error == EAGAIN) {
- nl_sock_record_errors__(transactions, n, 0);
- *done += n;
- error = 0;
- }
- break;
- }
- /* Match the reply up with a transaction. */
- seq = nl_msg_nlmsghdr(buf_txn->reply)->nlmsg_seq;
- if (seq < base_seq || seq >= base_seq + n) {
- VLOG_DBG_RL(&rl, "ignoring unexpected seq %#"PRIx32, seq);
- continue;
- }
- i = seq - base_seq;
- txn = transactions[i];
- /* Fill in the results for 'txn'. */
- if (nl_msg_nlmsgerr(buf_txn->reply, &txn->error)) {
- if (txn->reply) {
- ofpbuf_clear(txn->reply);
- }
- if (txn->error) {
- VLOG_DBG_RL(&rl, "received NAK error=%d (%s)",
- error, ovs_strerror(txn->error));
- }
- } else {
- txn->error = 0;
- if (txn->reply && txn != buf_txn) {
- /* Swap buffers. */
- struct ofpbuf *reply = buf_txn->reply;
- buf_txn->reply = txn->reply;
- txn->reply = reply;
- }
- }
- /* Fill in the results for transactions before 'txn'. (We have to do
- * this after the results for 'txn' itself because of the buffer swap
- * above.) */
- nl_sock_record_errors__(transactions, i, 0);
- /* Advance. */
- *done += i + 1;
- transactions += i + 1;
- n -= i + 1;
- base_seq += i + 1;
- }
- ofpbuf_uninit(&tmp_reply);
- return error;
- }
- /* Sends the 'request' member of the 'n' transactions in 'transactions' on
- * 'sock', in order, and receives responses to all of them. Fills in the
- * 'error' member of each transaction with 0 if it was successful, otherwise
- * with a positive errno value. If 'reply' is nonnull, then it will be filled
- * with the reply if the message receives a detailed reply. In other cases,
- * i.e. where the request failed or had no reply beyond an indication of
- * success, 'reply' will be cleared if it is nonnull.
- *
- * The caller is responsible for destroying each request and reply, and the
- * transactions array itself.
- *
- * Before sending each message, this function will finalize nlmsg_len in each
- * 'request' to match the ofpbuf's size, set nlmsg_pid to 'sock''s pid, and
- * initialize nlmsg_seq.
- *
- * Bare Netlink is an unreliable transport protocol. This function layers
- * reliable delivery and reply semantics on top of bare Netlink. See
- * nl_sock_transact() for some caveats.
- */
- void
- nl_sock_transact_multiple(struct nl_sock *sock,
- struct nl_transaction **transactions, size_t n)
- {
- int max_batch_count;
- int error;
- if (!n) {
- return;
- }
- /* In theory, every request could have a 64 kB reply. But the default and
- * maximum socket rcvbuf size with typical Dom0 memory sizes both tend to
- * be a bit below 128 kB, so that would only allow a single message in a
- * "batch". So we assume that replies average (at most) 4 kB, which allows
- * a good deal of batching.
- *
- * In practice, most of the requests that we batch either have no reply at
- * all or a brief reply. */
- max_batch_count = MAX(sock->rcvbuf / 4096, 1);
- max_batch_count = MIN(max_batch_count, max_iovs);
- while (n > 0) {
- size_t count, bytes;
- size_t done;
- /* Batch up to 'max_batch_count' transactions. But cap it at about a
- * page of requests total because big skbuffs are expensive to
- * allocate in the kernel. */
- #if defined(PAGESIZE)
- enum { MAX_BATCH_BYTES = MAX(1, PAGESIZE - 512) };
- #else
- enum { MAX_BATCH_BYTES = 4096 - 512 };
- #endif
- bytes = transactions[0]->request->size;
- for (count = 1; count < n && count < max_batch_count; count++) {
- if (bytes + transactions[count]->request->size > MAX_BATCH_BYTES) {
- break;
- }
- bytes += transactions[count]->request->size;
- }
- error = nl_sock_transact_multiple__(sock, transactions, count, &done);
- transactions += done;
- n -= done;
- if (error == ENOBUFS) {
- VLOG_DBG_RL(&rl, "receive buffer overflow, resending request");
- } else if (error) {
- VLOG_ERR_RL(&rl, "transaction error (%s)", ovs_strerror(error));
- nl_sock_record_errors__(transactions, n, error);
- }
- }
- }
- /* Sends 'request' to the kernel via 'sock' and waits for a response. If
- * successful, returns 0. On failure, returns a positive errno value.
- *
- * If 'replyp' is nonnull, then on success '*replyp' is set to the kernel's
- * reply, which the caller is responsible for freeing with ofpbuf_delete(), and
- * on failure '*replyp' is set to NULL. If 'replyp' is null, then the kernel's
- * reply, if any, is discarded.
- *
- * Before the message is sent, nlmsg_len in 'request' will be finalized to
- * match msg->size, nlmsg_pid will be set to 'sock''s pid, and nlmsg_seq will
- * be initialized, NLM_F_ACK will be set in nlmsg_flags.
- *
- * The caller is responsible for destroying 'request'.
- *
- * Bare Netlink is an unreliable transport protocol. This function layers
- * reliable delivery and reply semantics on top of bare Netlink.
- *
- * In Netlink, sending a request to the kernel is reliable enough, because the
- * kernel will tell us if the message cannot be queued (and we will in that
- * case put it on the transmit queue and wait until it can be delivered).
- *
- * Receiving the reply is the real problem: if the socket buffer is full when
- * the kernel tries to send the reply, the reply will be dropped. However, the
- * kernel sets a flag that a reply has been dropped. The next call to recv
- * then returns ENOBUFS. We can then re-send the request.
- *
- * Caveats:
- *
- * 1. Netlink depends on sequence numbers to match up requests and
- * replies. The sender of a request supplies a sequence number, and
- * the reply echos back that sequence number.
- *
- * This is fine, but (1) some kernel netlink implementations are
- * broken, in that they fail to echo sequence numbers and (2) this
- * function will drop packets with non-matching sequence numbers, so
- * that only a single request can be usefully transacted at a time.
- *
- * 2. Resending the request causes it to be re-executed, so the request
- * needs to be idempotent.
- */
- int
- nl_sock_transact(struct nl_sock *sock, const struct ofpbuf *request,
- struct ofpbuf **replyp)
- {
- struct nl_transaction *transactionp;
- struct nl_transaction transaction;
- transaction.request = CONST_CAST(struct ofpbuf *, request);
- transaction.reply = replyp ? ofpbuf_new(1024) : NULL;
- transactionp = &transaction;
- nl_sock_transact_multiple(sock, &transactionp, 1);
- if (replyp) {
- if (transaction.error) {
- ofpbuf_delete(transaction.reply);
- *replyp = NULL;
- } else {
- *replyp = transaction.reply;
- }
- }
- return transaction.error;
- }
- /* Drain all the messages currently in 'sock''s receive queue. */
- int
- nl_sock_drain(struct nl_sock *sock)
- {
- return drain_rcvbuf(sock->fd);
- }
- /* Starts a Netlink "dump" operation, by sending 'request' to the kernel on a
- * Netlink socket created with the given 'protocol', and initializes 'dump' to
- * reflect the state of the operation.
- *
- * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will
- * be set to the Netlink socket's pid, before the message is sent. NLM_F_DUMP
- * and NLM_F_ACK will be set in nlmsg_flags.
- *
- * The design of this Netlink socket library ensures that the dump is reliable.
- *
- * This function provides no status indication. An error status for the entire
- * dump operation is provided when it is completed by calling nl_dump_done().
- *
- * The caller is responsible for destroying 'request'.
- */
- void
- nl_dump_start(struct nl_dump *dump, int protocol, const struct ofpbuf *request)
- {
- ofpbuf_init(&dump->buffer, 4096);
- dump->status = nl_pool_alloc(protocol, &dump->sock);
- if (dump->status) {
- return;
- }
- nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK;
- dump->status = nl_sock_send__(dump->sock, request,
- nl_sock_allocate_seq(dump->sock, 1), true);
- dump->seq = nl_msg_nlmsghdr(request)->nlmsg_seq;
- }
- /* Helper function for nl_dump_next(). */
- static int
- nl_dump_recv(struct nl_dump *dump)
- {
- struct nlmsghdr *nlmsghdr;
- int retval;
- retval = nl_sock_recv__(dump->sock, &dump->buffer, true);
- if (retval) {
- return retval == EINTR ? EAGAIN : retval;
- }
- nlmsghdr = nl_msg_nlmsghdr(&dump->buffer);
- if (dump->seq != nlmsghdr->nlmsg_seq) {
- VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32,
- nlmsghdr->nlmsg_seq, dump->seq);
- return EAGAIN;
- }
- if (nl_msg_nlmsgerr(&dump->buffer, &retval)) {
- VLOG_INFO_RL(&rl, "netlink dump request error (%s)",
- ovs_strerror(retval));
- return retval && retval != EAGAIN ? retval : EPROTO;
- }
- return 0;
- }
- /* Attempts to retrieve another reply from 'dump', which must have been
- * initialized with nl_dump_start().
- *
- * If successful, returns true and points 'reply->data' and 'reply->size' to
- * the message that was retrieved. The caller must not modify 'reply' (because
- * it points into the middle of a larger buffer).
- *
- * On failure, returns false and sets 'reply->data' to NULL and 'reply->size'
- * to 0. Failure might indicate an actual error or merely the end of replies.
- * An error status for the entire dump operation is provided when it is
- * completed by calling nl_dump_done().
- */
- bool
- nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply)
- {
- struct nlmsghdr *nlmsghdr;
- reply->data = NULL;
- reply->size = 0;
- if (dump->status) {
- return false;
- }
- while (!dump->buffer.size) {
- int retval = nl_dump_recv(dump);
- if (retval) {
- ofpbuf_clear(&dump->buffer);
- if (retval != EAGAIN) {
- dump->status = retval;
- return false;
- }
- }
- }
- nlmsghdr = nl_msg_next(&dump->buffer, reply);
- if (!nlmsghdr) {
- VLOG_WARN_RL(&rl, "netlink dump reply contains message fragment");
- dump->status = EPROTO;
- return false;
- } else if (nlmsghdr->nlmsg_type == NLMSG_DONE) {
- dump->status = EOF;
- return false;
- }
- return true;
- }
- /* Completes Netlink dump operation 'dump', which must have been initialized
- * with nl_dump_start(). Returns 0 if the dump operation was error-free,
- * otherwise a positive errno value describing the problem. */
- int
- nl_dump_done(struct nl_dump *dump)
- {
- /* Drain any remaining messages that the client didn't read. Otherwise the
- * kernel will continue to queue them up and waste buffer space.
- *
- * XXX We could just destroy and discard the socket in this case. */
- while (!dump->status) {
- struct ofpbuf reply;
- if (!nl_dump_next(dump, &reply)) {
- ovs_assert(dump->status);
- }
- }
- nl_pool_release(dump->sock);
- ofpbuf_uninit(&dump->buffer);
- return dump->status == EOF ? 0 : dump->status;
- }
- /* Causes poll_block() to wake up when any of the specified 'events' (which is
- * a OR'd combination of POLLIN, POLLOUT, etc.) occur on 'sock'. */
- void
- nl_sock_wait(const struct nl_sock *sock, short int events)
- {
- poll_fd_wait(sock->fd, events);
- }
- /* Returns the underlying fd for 'sock', for use in "poll()"-like operations
- * that can't use nl_sock_wait().
- *
- * It's a little tricky to use the returned fd correctly, because nl_sock does
- * "copy on write" to allow a single nl_sock to be used for notifications,
- * transactions, and dumps. If 'sock' is used only for notifications and
- * transactions (and never for dump) then the usage is safe. */
- int
- nl_sock_fd(const struct nl_sock *sock)
- {
- return sock->fd;
- }
- /* Returns the PID associated with this socket. */
- uint32_t
- nl_sock_pid(const struct nl_sock *sock)
- {
- return sock->pid;
- }
- /* Miscellaneous. */
- struct genl_family {
- struct hmap_node hmap_node;
- uint16_t id;
- char *name;
- };
- static struct hmap genl_families = HMAP_INITIALIZER(&genl_families);
- static const struct nl_policy family_policy[CTRL_ATTR_MAX + 1] = {
- [CTRL_ATTR_FAMILY_ID] = {.type = NL_A_U16},
- [CTRL_ATTR_MCAST_GROUPS] = {.type = NL_A_NESTED, .optional = true},
- };
- static struct genl_family *
- find_genl_family_by_id(uint16_t id)
- {
- struct genl_family *family;
- HMAP_FOR_EACH_IN_BUCKET (family, hmap_node, hash_int(id, 0),
- &genl_families) {
- if (family->id == id) {
- return family;
- }
- }
- return NULL;
- }
- static void
- define_genl_family(uint16_t id, const char *name)
- {
- struct genl_family *family = find_genl_family_by_id(id);
- if (family) {
- if (!strcmp(family->name, name)) {
- return;
- }
- free(family->name);
- } else {
- family = xmalloc(sizeof *family);
- family->id = id;
- hmap_insert(&genl_families, &family->hmap_node, hash_int(id, 0));
- }
- family->name = xstrdup(name);
- }
- static const char *
- genl_family_to_name(uint16_t id)
- {
- if (id == GENL_ID_CTRL) {
- return "control";
- } else {
- struct genl_family *family = find_genl_family_by_id(id);
- return family ? family->name : "unknown";
- }
- }
- static int
- do_lookup_genl_family(const char *name, struct nlattr **attrs,
- struct ofpbuf **replyp)
- {
- struct nl_sock *sock;
- struct ofpbuf request, *reply;
- int error;
- *replyp = NULL;
- error = nl_sock_create(NETLINK_GENERIC, &sock);
- if (error) {
- return error;
- }
- ofpbuf_init(&request, 0);
- nl_msg_put_genlmsghdr(&request, 0, GENL_ID_CTRL, NLM_F_REQUEST,
- CTRL_CMD_GETFAMILY, 1);
- nl_msg_put_string(&request, CTRL_ATTR_FAMILY_NAME, name);
- error = nl_sock_transact(sock, &request, &reply);
- ofpbuf_uninit(&request);
- if (error) {
- nl_sock_destroy(sock);
- return error;
- }
- if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN,
- family_policy, attrs, ARRAY_SIZE(family_policy))
- || nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]) == 0) {
- nl_sock_destroy(sock);
- ofpbuf_delete(reply);
- return EPROTO;
- }
- nl_sock_destroy(sock);
- *replyp = reply;
- return 0;
- }
- /* Finds the multicast group called 'group_name' in genl family 'family_name'.
- * When successful, writes its result to 'multicast_group' and returns 0.
- * Otherwise, clears 'multicast_group' and returns a positive error code.
- */
- int
- nl_lookup_genl_mcgroup(const char *family_name, const char *group_name,
- unsigned int *multicast_group)
- {
- struct nlattr *family_attrs[ARRAY_SIZE(family_policy)];
- const struct nlattr *mc;
- struct ofpbuf *reply;
- unsigned int left;
- int error;
- *multicast_group = 0;
- error = do_lookup_genl_family(family_name, family_attrs, &reply);
- if (error) {
- return error;
- }
- if (!family_attrs[CTRL_ATTR_MCAST_GROUPS]) {
- error = EPROTO;
- goto exit;
- }
- NL_NESTED_FOR_EACH (mc, left, family_attrs[CTRL_ATTR_MCAST_GROUPS]) {
- static const struct nl_policy mc_policy[] = {
- [CTRL_ATTR_MCAST_GRP_ID] = {.type = NL_A_U32},
- [CTRL_ATTR_MCAST_GRP_NAME] = {.type = NL_A_STRING},
- };
- struct nlattr *mc_attrs[ARRAY_SIZE(mc_policy)];
- const char *mc_name;
- if (!nl_parse_nested(mc, mc_policy, mc_attrs, ARRAY_SIZE(mc_policy))) {
- error = EPROTO;
- goto exit;
- }
- mc_name = nl_attr_get_string(mc_attrs[CTRL_ATTR_MCAST_GRP_NAME]);
- if (!strcmp(group_name, mc_name)) {
- *multicast_group =
- nl_attr_get_u32(mc_attrs[CTRL_ATTR_MCAST_GRP_ID]);
- error = 0;
- goto exit;
- }
- }
- error = EPROTO;
- exit:
- ofpbuf_delete(reply);
- return error;
- }
- /* If '*number' is 0, translates the given Generic Netlink family 'name' to a
- * number and stores it in '*number'. If successful, returns 0 and the caller
- * may use '*number' as the family number. On failure, returns a positive
- * errno value and '*number' caches the errno value. */
- int
- nl_lookup_genl_family(const char *name, int *number)
- {
- if (*number == 0) {
- struct nlattr *attrs[ARRAY_SIZE(family_policy)];
- struct ofpbuf *reply;
- int error;
- error = do_lookup_genl_family(name, attrs, &reply);
- if (!error) {
- *number = nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]);
- define_genl_family(*number, name);
- } else {
- *number = -error;
- }
- ofpbuf_delete(reply);
- ovs_assert(*number != 0);
- }
- return *number > 0 ? 0 : -*number;
- }
- struct nl_pool {
- struct nl_sock *socks[16];
- int n;
- };
- static struct ovs_mutex pool_mutex = OVS_MUTEX_INITIALIZER;
- static struct nl_pool pools[MAX_LINKS] OVS_GUARDED_BY(pool_mutex);
- static int
- nl_pool_alloc(int protocol, struct nl_sock **sockp)
- {
- struct nl_sock *sock = NULL;
- struct nl_pool *pool;
- ovs_assert(protocol >= 0 && protocol < ARRAY_SIZE(pools));
- ovs_mutex_lock(&pool_mutex);
- pool = &pools[protocol];
- if (pool->n > 0) {
- sock = pool->socks[--pool->n];
- }
- ovs_mutex_unlock(&pool_mutex);
- if (sock) {
- *sockp = sock;
- return 0;
- } else {
- return nl_sock_create(protocol, sockp);
- }
- }
- static void
- nl_pool_release(struct nl_sock *sock)
- {
- if (sock) {
- struct nl_pool *pool = &pools[sock->protocol];
- ovs_mutex_lock(&pool_mutex);
- if (pool->n < ARRAY_SIZE(pool->socks)) {
- pool->socks[pool->n++] = sock;
- sock = NULL;
- }
- ovs_mutex_unlock(&pool_mutex);
- nl_sock_destroy(sock);
- }
- }
- int
- nl_transact(int protocol, const struct ofpbuf *request,
- struct ofpbuf **replyp)
- {
- struct nl_sock *sock;
- int error;
- error = nl_pool_alloc(protocol, &sock);
- if (error) {
- *replyp = NULL;
- return error;
- }
- error = nl_sock_transact(sock, request, replyp);
- nl_pool_release(sock);
- return error;
- }
- void
- nl_transact_multiple(int protocol,
- struct nl_transaction **transactions, size_t n)
- {
- struct nl_sock *sock;
- int error;
- error = nl_pool_alloc(protocol, &sock);
- if (!error) {
- nl_sock_transact_multiple(sock, transactions, n);
- nl_pool_release(sock);
- } else {
- nl_sock_record_errors__(transactions, n, error);
- }
- }
- static uint32_t
- nl_sock_allocate_seq(struct nl_sock *sock, unsigned int n)
- {
- uint32_t seq = sock->next_seq;
- sock->next_seq += n;
- /* Make it impossible for the next request for sequence numbers to wrap
- * around to 0. Start over with 1 to avoid ever using a sequence number of
- * 0, because the kernel uses sequence number 0 for notifications. */
- if (sock->next_seq >= UINT32_MAX / 2) {
- sock->next_seq = 1;
- }
- return seq;
- }
- static void
- nlmsghdr_to_string(const struct nlmsghdr *h, int protocol, struct ds *ds)
- {
- struct nlmsg_flag {
- unsigned int bits;
- const char *name;
- };
- static const struct nlmsg_flag flags[] = {
- { NLM_F_REQUEST, "REQUEST" },
- { NLM_F_MULTI, "MULTI" },
- { NLM_F_ACK, "ACK" },
- { NLM_F_ECHO, "ECHO" },
- { NLM_F_DUMP, "DUMP" },
- { NLM_F_ROOT, "ROOT" },
- { NLM_F_MATCH, "MATCH" },
- { NLM_F_ATOMIC, "ATOMIC" },
- };
- const struct nlmsg_flag *flag;
- uint16_t flags_left;
- ds_put_format(ds, "nl(len:%"PRIu32", type=%"PRIu16,
- h->nlmsg_len, h->nlmsg_type);
- if (h->nlmsg_type == NLMSG_NOOP) {
- ds_put_cstr(ds, "(no-op)");
- } else if (h->nlmsg_type == NLMSG_ERROR) {
- ds_put_cstr(ds, "(error)");
- } else if (h->nlmsg_type == NLMSG_DONE) {
- ds_put_cstr(ds, "(done)");
- } else if (h->nlmsg_type == NLMSG_OVERRUN) {
- ds_put_cstr(ds, "(overrun)");
- } else if (h->nlmsg_type < NLMSG_MIN_TYPE) {
- ds_put_cstr(ds, "(reserved)");
- } else if (protocol == NETLINK_GENERIC) {
- ds_put_format(ds, "(%s)", genl_family_to_name(h->nlmsg_type));
- } else {
- ds_put_cstr(ds, "(family-defined)");
- }
- ds_put_format(ds, ", flags=%"PRIx16, h->nlmsg_flags);
- flags_left = h->nlmsg_flags;
- for (flag = flags; flag < &flags[ARRAY_SIZE(flags)]; flag++) {
- if ((flags_left & flag->bits) == flag->bits) {
- ds_put_format(ds, "[%s]", flag->name);
- flags_left &= ~flag->bits;
- }
- }
- if (flags_left) {
- ds_put_format(ds, "[OTHER:%"PRIx16"]", flags_left);
- }
- ds_put_format(ds, ", seq=%"PRIx32", pid=%"PRIu32,
- h->nlmsg_seq, h->nlmsg_pid);
- }
- static char *
- nlmsg_to_string(const struct ofpbuf *buffer, int protocol)
- {
- struct ds ds = DS_EMPTY_INITIALIZER;
- const struct nlmsghdr *h = ofpbuf_at(buffer, 0, NLMSG_HDRLEN);
- if (h) {
- nlmsghdr_to_string(h, protocol, &ds);
- if (h->nlmsg_type == NLMSG_ERROR) {
- const struct nlmsgerr *e;
- e = ofpbuf_at(buffer, NLMSG_HDRLEN,
- NLMSG_ALIGN(sizeof(struct nlmsgerr)));
- if (e) {
- ds_put_format(&ds, " error(%d", e->error);
- if (e->error < 0) {
- ds_put_format(&ds, "(%s)", ovs_strerror(-e->error));
- }
- ds_put_cstr(&ds, ", in-reply-to(");
- nlmsghdr_to_string(&e->msg, protocol, &ds);
- ds_put_cstr(&ds, "))");
- } else {
- ds_put_cstr(&ds, " error(truncated)");
- }
- } else if (h->nlmsg_type == NLMSG_DONE) {
- int *error = ofpbuf_at(buffer, NLMSG_HDRLEN, sizeof *error);
- if (error) {
- ds_put_format(&ds, " done(%d", *error);
- if (*error < 0) {
- ds_put_format(&ds, "(%s)", ovs_strerror(-*error));
- }
- ds_put_cstr(&ds, ")");
- } else {
- ds_put_cstr(&ds, " done(truncated)");
- }
- } else if (protocol == NETLINK_GENERIC) {
- struct genlmsghdr *genl = nl_msg_genlmsghdr(buffer);
- if (genl) {
- ds_put_format(&ds, ",genl(cmd=%"PRIu8",version=%"PRIu8")",
- genl->cmd, genl->version);
- }
- }
- } else {
- ds_put_cstr(&ds, "nl(truncated)");
- }
- return ds.string;
- }
- static void
- log_nlmsg(const char *function, int error,
- const void *message, size_t size, int protocol)
- {
- struct ofpbuf buffer;
- char *nlmsg;
- if (!VLOG_IS_DBG_ENABLED()) {
- return;
- }
- ofpbuf_use_const(&buffer, message, size);
- nlmsg = nlmsg_to_string(&buffer, protocol);
- VLOG_DBG_RL(&rl, "%s (%s): %s", function, ovs_strerror(error), nlmsg);
- free(nlmsg);
- }