/* * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 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 #include "netlink-socket.h" #include #include #include #include #include #include #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 "seq.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_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 = ofpbuf_size(msg); nlmsg->nlmsg_seq = nlmsg_seq; nlmsg->nlmsg_pid = sock->pid; do { int retval; retval = send(sock->fd, ofpbuf_data(msg), ofpbuf_size(msg), wait ? 0 : MSG_DONTWAIT); error = retval < 0 ? errno : 0; } while (error == EINTR); log_nlmsg(__func__, error, ofpbuf_data(msg), ofpbuf_size(msg), 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 ofpbuf_size(msg), 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 ofpbuf_size(msg), 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 = ofpbuf_base(buf); 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 %"PRIuSIZE" bytes)", sizeof tail); return E2BIG; } nlmsghdr = ofpbuf_data(buf); if (retval < sizeof *nlmsghdr || nlmsghdr->nlmsg_len < sizeof *nlmsghdr || nlmsghdr->nlmsg_len > retval) { VLOG_ERR_RL(&rl, "received invalid nlmsg (%"PRIuSIZE"d bytes < %"PRIuSIZE")", retval, sizeof *nlmsghdr); return EPROTO; } ofpbuf_set_size(buf, MIN(retval, buf->allocated)); if (retval > buf->allocated) { COVERAGE_INC(netlink_recv_jumbo); ofpbuf_put(buf, tail, retval - buf->allocated); } log_nlmsg(__func__, 0, ofpbuf_data(buf), ofpbuf_size(buf), 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 = ofpbuf_size(txn->request); nlmsg->nlmsg_seq = base_seq + i; nlmsg->nlmsg_pid = sock->pid; iovs[i].iov_base = ofpbuf_data(txn->request); iovs[i].iov_len = ofpbuf_size(txn->request); } 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, ofpbuf_data(txn->request), ofpbuf_size(txn->request), 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 = ofpbuf_size(transactions[0]->request); for (count = 1; count < n && count < max_batch_count; count++) { if (bytes + ofpbuf_size(transactions[count]->request) > MAX_BATCH_BYTES) { break; } bytes += ofpbuf_size(transactions[count]->request); } 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 ofpbuf_size(msg), 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. * * 'request' must contain a Netlink message. Before sending the message, * nlmsg_len will be finalized to match request->size, and nlmsg_pid will be * set to the Netlink socket's pid. 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. nl_dump_done() provides an * error status for the entire dump operation. * * The caller must eventually destroy 'request'. */ void nl_dump_start(struct nl_dump *dump, int protocol, const struct ofpbuf *request) { int status = nl_pool_alloc(protocol, &dump->sock); if (status) { return; } nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK; status = nl_sock_send__(dump->sock, request, nl_sock_allocate_seq(dump->sock, 1), true); atomic_init(&dump->status, status << 1); dump->nl_seq = nl_msg_nlmsghdr(request)->nlmsg_seq; dump->status_seq = seq_create(); } /* Attempts to retrieve another reply from 'dump' into 'buffer'. 'dump' must * have been initialized with nl_dump_start(), and 'buffer' must have been * initialized. 'buffer' should be at least NL_DUMP_BUFSIZE bytes long. * * If successful, returns true and points 'reply->data' and 'ofpbuf_size(reply)' to * the message that was retrieved. The caller must not modify 'reply' (because * it points within 'buffer', which will be used by future calls to this * function). * * On failure, returns false and sets 'reply->data' to NULL and 'ofpbuf_size(reply)' * 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(). * * Multiple threads may call this function, passing the same nl_dump, however * each must provide independent buffers. This function may cache multiple * replies in the buffer, and these will be processed before more replies are * fetched. When this function returns false, other threads may continue to * process replies in their buffers, but they will not fetch more replies. */ bool nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply, struct ofpbuf *buffer) { struct nlmsghdr *nlmsghdr; int error = 0; ofpbuf_set_data(reply, NULL); ofpbuf_set_size(reply, 0); /* If 'buffer' is empty, fetch another batch of nlmsgs. */ while (!ofpbuf_size(buffer)) { unsigned int status; int retval, seq; seq = seq_read(dump->status_seq); atomic_read(&dump->status, &status); if (status) { return false; } retval = nl_sock_recv__(dump->sock, buffer, false); if (retval) { ofpbuf_clear(buffer); if (retval == EAGAIN) { nl_sock_wait(dump->sock, POLLIN); seq_wait(dump->status_seq, seq); poll_block(); continue; } else { error = retval; goto exit; } } nlmsghdr = nl_msg_nlmsghdr(buffer); if (dump->nl_seq != nlmsghdr->nlmsg_seq) { VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32, nlmsghdr->nlmsg_seq, dump->nl_seq); ofpbuf_clear(buffer); continue; } if (nl_msg_nlmsgerr(buffer, &retval) && retval) { VLOG_INFO_RL(&rl, "netlink dump request error (%s)", ovs_strerror(retval)); error = retval == EAGAIN ? EPROTO : retval; ofpbuf_clear(buffer); goto exit; } } /* Fetch the next nlmsg in the current batch. */ nlmsghdr = nl_msg_next(buffer, reply); if (!nlmsghdr) { VLOG_WARN_RL(&rl, "netlink dump reply contains message fragment"); error = EPROTO; } else if (nlmsghdr->nlmsg_type == NLMSG_DONE) { error = EOF; } exit: if (error == EOF) { unsigned int old; atomic_or(&dump->status, 1, &old); seq_change(dump->status_seq); } else if (error) { atomic_store(&dump->status, error << 1); seq_change(dump->status_seq); } return !error; } /* 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) { int status; /* 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. */ atomic_read(&dump->status, &status); if (!status) { uint64_t tmp_reply_stub[NL_DUMP_BUFSIZE / 8]; struct ofpbuf reply, buf; ofpbuf_use_stub(&buf, tmp_reply_stub, sizeof tmp_reply_stub); while (nl_dump_next(dump, &reply, &buf)) { /* Nothing to do. */ } atomic_read(&dump->status, &status); ovs_assert(status); ofpbuf_uninit(&buf); } nl_pool_release(dump->sock); seq_destroy(dump->status_seq); return status >> 1; } /* 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); }