lib/netdev-provider.h \
lib/netdev.c \
lib/netdev.h \
+ lib/netlink.c \
+ lib/netlink.h \
lib/nx-match.c \
lib/nx-match.def \
lib/nx-match.h \
lib/netdev-vport.c \
lib/netdev-vport.h \
lib/netlink-protocol.h \
- lib/netlink.c \
- lib/netlink.h \
+ lib/netlink-socket.c \
+ lib/netlink-socket.h \
lib/rtnetlink.c \
lib/rtnetlink.h
endif
#include "netdev-provider.h"
#include "netdev-vport.h"
#include "netlink.h"
+#include "netlink-socket.h"
#include "ofpbuf.h"
#include "openflow/openflow.h"
#include "packets.h"
--- /dev/null
+/*
+ * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ *
+ * 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 <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "coverage.h"
+#include "dynamic-string.h"
+#include "netlink.h"
+#include "netlink-protocol.h"
+#include "ofpbuf.h"
+#include "poll-loop.h"
+#include "stress.h"
+#include "vlog.h"
+
+VLOG_DEFINE_THIS_MODULE(netlink_socket);
+
+COVERAGE_DEFINE(netlink_overflow);
+COVERAGE_DEFINE(netlink_received);
+COVERAGE_DEFINE(netlink_recv_retry);
+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 void log_nlmsg(const char *function, int error,
+ const void *message, size_t size);
+\f
+/* Netlink sockets. */
+
+struct nl_sock
+{
+ int fd;
+ uint32_t pid;
+};
+
+static int alloc_pid(uint32_t *);
+static void free_pid(uint32_t);
+
+/* 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.
+ *
+ * If 'multicast_group' is nonzero, the new socket subscribes to the specified
+ * netlink multicast group. (A netlink socket may listen to an arbitrary
+ * number of multicast groups, but so far we only need one at a time.)
+ *
+ * Nonzero 'so_sndbuf' or 'so_rcvbuf' override the kernel default send or
+ * receive buffer size, respectively.
+ */
+int
+nl_sock_create(int protocol, int multicast_group,
+ size_t so_sndbuf, size_t so_rcvbuf, struct nl_sock **sockp)
+{
+ struct nl_sock *sock;
+ struct sockaddr_nl local, remote;
+ int retval = 0;
+
+ *sockp = NULL;
+ sock = malloc(sizeof *sock);
+ if (sock == NULL) {
+ return ENOMEM;
+ }
+
+ sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
+ if (sock->fd < 0) {
+ VLOG_ERR("fcntl: %s", strerror(errno));
+ goto error;
+ }
+
+ retval = alloc_pid(&sock->pid);
+ if (retval) {
+ goto error;
+ }
+
+ if (so_sndbuf != 0
+ && setsockopt(sock->fd, SOL_SOCKET, SO_SNDBUF,
+ &so_sndbuf, sizeof so_sndbuf) < 0) {
+ VLOG_ERR("setsockopt(SO_SNDBUF,%zu): %s", so_sndbuf, strerror(errno));
+ goto error_free_pid;
+ }
+
+ if (so_rcvbuf != 0
+ && setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUF,
+ &so_rcvbuf, sizeof so_rcvbuf) < 0) {
+ VLOG_ERR("setsockopt(SO_RCVBUF,%zu): %s", so_rcvbuf, strerror(errno));
+ goto error_free_pid;
+ }
+
+ /* Bind local address as our selected pid. */
+ memset(&local, 0, sizeof local);
+ local.nl_family = AF_NETLINK;
+ local.nl_pid = sock->pid;
+ if (multicast_group > 0 && multicast_group <= 32) {
+ /* This method of joining multicast groups is supported by old kernels,
+ * but it only allows 32 multicast groups per protocol. */
+ local.nl_groups |= 1ul << (multicast_group - 1);
+ }
+ if (bind(sock->fd, (struct sockaddr *) &local, sizeof local) < 0) {
+ VLOG_ERR("bind(%"PRIu32"): %s", sock->pid, strerror(errno));
+ goto error_free_pid;
+ }
+
+ /* Bind remote address as the kernel (pid 0). */
+ 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", strerror(errno));
+ goto error_free_pid;
+ }
+
+ /* Older kernel headers failed to define this macro. We want our programs
+ * to support the newer kernel features even if compiled with older
+ * headers, so define it ourselves in such a case. */
+#ifndef NETLINK_ADD_MEMBERSHIP
+#define NETLINK_ADD_MEMBERSHIP 1
+#endif
+
+ /* This method of joining multicast groups is only supported by newish
+ * kernels, but it allows for an arbitrary number of multicast groups. */
+ if (multicast_group > 32
+ && setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
+ &multicast_group, sizeof multicast_group) < 0) {
+ VLOG_ERR("setsockopt(NETLINK_ADD_MEMBERSHIP,%d): %s",
+ multicast_group, strerror(errno));
+ goto error_free_pid;
+ }
+
+ *sockp = sock;
+ return 0;
+
+error_free_pid:
+ free_pid(sock->pid);
+error:
+ if (retval == 0) {
+ retval = errno;
+ if (retval == 0) {
+ retval = EINVAL;
+ }
+ }
+ if (sock->fd >= 0) {
+ close(sock->fd);
+ }
+ free(sock);
+ return retval;
+}
+
+/* Destroys netlink socket 'sock'. */
+void
+nl_sock_destroy(struct nl_sock *sock)
+{
+ if (sock) {
+ close(sock->fd);
+ free_pid(sock->pid);
+ free(sock);
+ }
+}
+
+/* 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, and
+ * nlmsg_pid will be set to 'sock''s pid, 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)
+{
+ struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg);
+ int error;
+
+ nlmsg->nlmsg_len = msg->size;
+ 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);
+ if (!error) {
+ COVERAGE_INC(netlink_sent);
+ }
+ return error;
+}
+
+/* Tries to send the 'n_iov' chunks of data in 'iov' to the kernel on 'sock' as
+ * a single Netlink message. (The message must be fully formed and not require
+ * finalization of its nlmsg_len or nlmsg_pid fields.)
+ *
+ * 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_sendv(struct nl_sock *sock, const struct iovec iov[], size_t n_iov,
+ bool wait)
+{
+ struct msghdr msg;
+ int error;
+
+ COVERAGE_INC(netlink_send);
+ memset(&msg, 0, sizeof msg);
+ msg.msg_iov = (struct iovec *) iov;
+ msg.msg_iovlen = n_iov;
+ do {
+ int retval;
+ retval = sendmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
+ error = retval < 0 ? errno : 0;
+ } while (error == EINTR);
+ if (error != EAGAIN) {
+ log_nlmsg(__func__, error, iov[0].iov_base, iov[0].iov_len);
+ if (!error) {
+ COVERAGE_INC(netlink_sent);
+ }
+ }
+ return error;
+}
+
+/* This stress option is useful for testing that OVS properly tolerates
+ * -ENOBUFS on NetLink sockets. Such errors are unavoidable because they can
+ * occur if the kernel cannot temporarily allocate enough GFP_ATOMIC memory to
+ * reply to a request. They can also occur if messages arrive on a multicast
+ * channel faster than OVS can process them. */
+STRESS_OPTION(
+ netlink_overflow, "simulate netlink socket receive buffer overflow",
+ 5, 1, -1, 100);
+
+/* Tries to receive a netlink message from the kernel on 'sock'. If
+ * successful, stores the received message into '*bufp' and returns 0. The
+ * caller is responsible for destroying the message with ofpbuf_delete(). On
+ * failure, returns a positive errno value and stores a null pointer into
+ * '*bufp'.
+ *
+ * If 'wait' is true, nl_sock_recv waits for a message to be ready; otherwise,
+ * returns EAGAIN if the 'sock' receive buffer is empty. */
+int
+nl_sock_recv(struct nl_sock *sock, struct ofpbuf **bufp, bool wait)
+{
+ uint8_t tmp;
+ ssize_t bufsize = 2048;
+ ssize_t nbytes, nbytes2;
+ struct ofpbuf *buf;
+ struct nlmsghdr *nlmsghdr;
+ struct iovec iov;
+ struct msghdr msg = {
+ .msg_name = NULL,
+ .msg_namelen = 0,
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_control = NULL,
+ .msg_controllen = 0,
+ .msg_flags = 0
+ };
+
+ buf = ofpbuf_new(bufsize);
+ *bufp = NULL;
+
+try_again:
+ /* Attempt to read the message. We don't know the size of the data
+ * yet, so we take a guess at 2048. If we're wrong, we keep trying
+ * and doubling the buffer size each time.
+ */
+ nlmsghdr = ofpbuf_put_uninit(buf, bufsize);
+ iov.iov_base = nlmsghdr;
+ iov.iov_len = bufsize;
+ do {
+ nbytes = recvmsg(sock->fd, &msg, (wait ? 0 : MSG_DONTWAIT) | MSG_PEEK);
+ } while (nbytes < 0 && errno == EINTR);
+ if (nbytes < 0) {
+ ofpbuf_delete(buf);
+ return errno;
+ }
+ if (msg.msg_flags & MSG_TRUNC) {
+ COVERAGE_INC(netlink_recv_retry);
+ bufsize *= 2;
+ ofpbuf_reinit(buf, bufsize);
+ goto try_again;
+ }
+ buf->size = nbytes;
+
+ /* We successfully read the message, so recv again to clear the queue */
+ iov.iov_base = &tmp;
+ iov.iov_len = 1;
+ do {
+ nbytes2 = recvmsg(sock->fd, &msg, MSG_DONTWAIT);
+ } while (nbytes2 < 0 && errno == EINTR);
+ if (nbytes2 < 0) {
+ if (errno == ENOBUFS) {
+ /* The kernel is notifying us that a message it tried to send to us
+ * was dropped. We have to pass this along to the caller in case
+ * it wants to retry a request. So kill the buffer, which we can
+ * re-read next time. */
+ COVERAGE_INC(netlink_overflow);
+ ofpbuf_delete(buf);
+ return ENOBUFS;
+ } else {
+ VLOG_ERR_RL(&rl, "failed to remove nlmsg from socket: %s\n",
+ strerror(errno));
+ }
+ }
+ if (nbytes < sizeof *nlmsghdr
+ || nlmsghdr->nlmsg_len < sizeof *nlmsghdr
+ || nlmsghdr->nlmsg_len > nbytes) {
+ VLOG_ERR_RL(&rl, "received invalid nlmsg (%zd bytes < %d)",
+ bufsize, NLMSG_HDRLEN);
+ ofpbuf_delete(buf);
+ return EPROTO;
+ }
+
+ if (STRESS(netlink_overflow)) {
+ ofpbuf_delete(buf);
+ return ENOBUFS;
+ }
+
+ *bufp = buf;
+ log_nlmsg(__func__, 0, buf->data, buf->size);
+ COVERAGE_INC(netlink_received);
+
+ return 0;
+}
+
+/* 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.
+ *
+ * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will
+ * be set to 'sock''s pid, before the message is sent. 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)
+{
+ uint32_t seq = nl_msg_nlmsghdr(request)->nlmsg_seq;
+ struct nlmsghdr *nlmsghdr;
+ struct ofpbuf *reply;
+ int retval;
+
+ if (replyp) {
+ *replyp = NULL;
+ }
+
+ /* Ensure that we get a reply even if this message doesn't ordinarily call
+ * for one. */
+ nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_ACK;
+
+send:
+ retval = nl_sock_send(sock, request, true);
+ if (retval) {
+ return retval;
+ }
+
+recv:
+ retval = nl_sock_recv(sock, &reply, true);
+ if (retval) {
+ if (retval == ENOBUFS) {
+ COVERAGE_INC(netlink_overflow);
+ VLOG_DBG_RL(&rl, "receive buffer overflow, resending request");
+ goto send;
+ } else {
+ return retval;
+ }
+ }
+ nlmsghdr = nl_msg_nlmsghdr(reply);
+ if (seq != nlmsghdr->nlmsg_seq) {
+ VLOG_DBG_RL(&rl, "ignoring seq %"PRIu32" != expected %"PRIu32,
+ nl_msg_nlmsghdr(reply)->nlmsg_seq, seq);
+ ofpbuf_delete(reply);
+ goto recv;
+ }
+
+ /* If the reply is an error, discard the reply and return the error code.
+ *
+ * Except: if the reply is just an acknowledgement (error code of 0), and
+ * the caller is interested in the reply (replyp != NULL), pass the reply
+ * up to the caller. Otherwise the caller will get a return value of 0
+ * and null '*replyp', which makes unwary callers likely to segfault. */
+ if (nl_msg_nlmsgerr(reply, &retval) && (retval || !replyp)) {
+ ofpbuf_delete(reply);
+ if (retval) {
+ VLOG_DBG_RL(&rl, "received NAK error=%d (%s)",
+ retval, strerror(retval));
+ }
+ return retval != EAGAIN ? retval : EPROTO;
+ }
+
+ if (replyp) {
+ *replyp = reply;
+ } else {
+ ofpbuf_delete(reply);
+ }
+ return 0;
+}
+
+/* Starts a Netlink "dump" operation, by sending 'request' to the kernel via
+ * 'sock', 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 'sock''s pid, before the message is sent. NLM_F_DUMP and
+ * NLM_F_ACK will be set in nlmsg_flags.
+ *
+ * The properties of Netlink make dump operations reliable as long as all of
+ * the following are true:
+ *
+ * - At most a single dump is in progress at a time on a given nl_sock.
+ *
+ * - The nl_sock is not subscribed to any multicast groups.
+ *
+ * - The nl_sock is not used to send any other messages before the dump
+ * operation is complete.
+ *
+ * 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'. The caller must not
+ * close 'sock' before it completes the dump operation (by calling
+ * nl_dump_done()).
+ */
+void
+nl_dump_start(struct nl_dump *dump,
+ struct nl_sock *sock, const struct ofpbuf *request)
+{
+ struct nlmsghdr *nlmsghdr = nl_msg_nlmsghdr(request);
+ nlmsghdr->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK;
+ dump->seq = nlmsghdr->nlmsg_seq;
+ dump->sock = sock;
+ dump->status = nl_sock_send(sock, request, true);
+ dump->buffer = NULL;
+}
+
+/* Helper function for nl_dump_next(). */
+static int
+nl_dump_recv(struct nl_dump *dump, struct ofpbuf **bufferp)
+{
+ struct nlmsghdr *nlmsghdr;
+ struct ofpbuf *buffer;
+ int retval;
+
+ retval = nl_sock_recv(dump->sock, bufferp, true);
+ if (retval) {
+ return retval == EINTR ? EAGAIN : retval;
+ }
+ buffer = *bufferp;
+
+ nlmsghdr = nl_msg_nlmsghdr(buffer);
+ if (dump->seq != nlmsghdr->nlmsg_seq) {
+ VLOG_DBG_RL(&rl, "ignoring seq %"PRIu32" != expected %"PRIu32,
+ nlmsghdr->nlmsg_seq, dump->seq);
+ return EAGAIN;
+ }
+
+ if (nl_msg_nlmsgerr(buffer, &retval)) {
+ VLOG_INFO_RL(&rl, "netlink dump request error (%s)",
+ 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;
+ }
+
+ if (dump->buffer && !dump->buffer->size) {
+ ofpbuf_delete(dump->buffer);
+ dump->buffer = NULL;
+ }
+ while (!dump->buffer) {
+ int retval = nl_dump_recv(dump, &dump->buffer);
+ if (retval) {
+ ofpbuf_delete(dump->buffer);
+ dump->buffer = NULL;
+ 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. */
+ while (!dump->status) {
+ struct ofpbuf reply;
+ if (!nl_dump_next(dump, &reply)) {
+ assert(dump->status);
+ }
+ }
+
+ ofpbuf_delete(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);
+}
+\f
+/* Miscellaneous. */
+
+static const struct nl_policy family_policy[CTRL_ATTR_MAX + 1] = {
+ [CTRL_ATTR_FAMILY_ID] = {.type = NL_A_U16},
+};
+
+static int do_lookup_genl_family(const char *name)
+{
+ struct nl_sock *sock;
+ struct ofpbuf request, *reply;
+ struct nlattr *attrs[ARRAY_SIZE(family_policy)];
+ int retval;
+
+ retval = nl_sock_create(NETLINK_GENERIC, 0, 0, 0, &sock);
+ if (retval) {
+ return -retval;
+ }
+
+ 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);
+ retval = nl_sock_transact(sock, &request, &reply);
+ ofpbuf_uninit(&request);
+ if (retval) {
+ nl_sock_destroy(sock);
+ return -retval;
+ }
+
+ if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN,
+ family_policy, attrs, ARRAY_SIZE(family_policy))) {
+ nl_sock_destroy(sock);
+ ofpbuf_delete(reply);
+ return -EPROTO;
+ }
+
+ retval = nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]);
+ if (retval == 0) {
+ retval = -EPROTO;
+ }
+ nl_sock_destroy(sock);
+ ofpbuf_delete(reply);
+ return retval;
+}
+
+/* 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) {
+ *number = do_lookup_genl_family(name);
+ assert(*number != 0);
+ }
+ return *number > 0 ? 0 : -*number;
+}
+\f
+/* Netlink PID.
+ *
+ * Every Netlink socket must be bound to a unique 32-bit PID. By convention,
+ * programs that have a single Netlink socket use their Unix process ID as PID,
+ * and programs with multiple Netlink sockets add a unique per-socket
+ * identifier in the bits above the Unix process ID.
+ *
+ * The kernel has Netlink PID 0.
+ */
+
+/* Parameters for how many bits in the PID should come from the Unix process ID
+ * and how many unique per-socket. */
+#define SOCKET_BITS 10
+#define MAX_SOCKETS (1u << SOCKET_BITS)
+
+#define PROCESS_BITS (32 - SOCKET_BITS)
+#define MAX_PROCESSES (1u << PROCESS_BITS)
+#define PROCESS_MASK ((uint32_t) (MAX_PROCESSES - 1))
+
+/* Bit vector of unused socket identifiers. */
+static uint32_t avail_sockets[ROUND_UP(MAX_SOCKETS, 32)];
+
+/* Allocates and returns a new Netlink PID. */
+static int
+alloc_pid(uint32_t *pid)
+{
+ int i;
+
+ for (i = 0; i < MAX_SOCKETS; i++) {
+ if ((avail_sockets[i / 32] & (1u << (i % 32))) == 0) {
+ avail_sockets[i / 32] |= 1u << (i % 32);
+ *pid = (getpid() & PROCESS_MASK) | (i << PROCESS_BITS);
+ return 0;
+ }
+ }
+ VLOG_ERR("netlink pid space exhausted");
+ return ENOBUFS;
+}
+
+/* Makes the specified 'pid' available for reuse. */
+static void
+free_pid(uint32_t pid)
+{
+ int sock = pid >> PROCESS_BITS;
+ assert(avail_sockets[sock / 32] & (1u << (sock % 32)));
+ avail_sockets[sock / 32] &= ~(1u << (sock % 32));
+}
+\f
+static void
+nlmsghdr_to_string(const struct nlmsghdr *h, 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 {
+ 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"(%d:%d))",
+ h->nlmsg_seq, h->nlmsg_pid,
+ (int) (h->nlmsg_pid & PROCESS_MASK),
+ (int) (h->nlmsg_pid >> PROCESS_BITS));
+}
+
+static char *
+nlmsg_to_string(const struct ofpbuf *buffer)
+{
+ struct ds ds = DS_EMPTY_INITIALIZER;
+ const struct nlmsghdr *h = ofpbuf_at(buffer, 0, NLMSG_HDRLEN);
+ if (h) {
+ nlmsghdr_to_string(h, &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)", strerror(-e->error));
+ }
+ ds_put_cstr(&ds, ", in-reply-to(");
+ nlmsghdr_to_string(&e->msg, &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)", strerror(-*error));
+ }
+ ds_put_cstr(&ds, ")");
+ } else {
+ ds_put_cstr(&ds, " done(truncated)");
+ }
+ }
+ } 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)
+{
+ struct ofpbuf buffer;
+ char *nlmsg;
+
+ if (!VLOG_IS_DBG_ENABLED()) {
+ return;
+ }
+
+ ofpbuf_use_const(&buffer, message, size);
+ nlmsg = nlmsg_to_string(&buffer);
+ VLOG_DBG_RL(&rl, "%s (%s): %s", function, strerror(error), nlmsg);
+ free(nlmsg);
+}
+
+
--- /dev/null
+/*
+ * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ *
+ * 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.
+ */
+
+#ifndef NETLINK_SOCKET_H
+#define NETLINK_SOCKET_H 1
+
+/* Netlink socket definitions.
+ *
+ * Netlink is a datagram-based network protocol primarily for communication
+ * between user processes and the kernel, and mainly on Linux. Netlink is
+ * specified in RFC 3549, "Linux Netlink as an IP Services Protocol".
+ *
+ * Netlink is not suitable for use in physical networks of heterogeneous
+ * machines because host byte order is used throughout.
+ *
+ * This header file defines functions for working with Netlink sockets, which
+ * are Linux-specific. For Netlink protocol definitions, see
+ * netlink-protocol.h. For helper functions for working with Netlink messages,
+ * see netlink.h.
+ */
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/uio.h>
+
+struct ofpbuf;
+struct nl_sock;
+
+#ifndef HAVE_NETLINK
+#error "netlink-socket.h is only for hosts that support Netlink sockets"
+#endif
+
+/* Netlink sockets. */
+int nl_sock_create(int protocol, int multicast_group,
+ size_t so_sndbuf, size_t so_rcvbuf,
+ struct nl_sock **);
+void nl_sock_destroy(struct nl_sock *);
+
+int nl_sock_send(struct nl_sock *, const struct ofpbuf *, bool wait);
+int nl_sock_sendv(struct nl_sock *sock, const struct iovec iov[], size_t n_iov,
+ bool wait);
+int nl_sock_recv(struct nl_sock *, struct ofpbuf **, bool wait);
+int nl_sock_transact(struct nl_sock *, const struct ofpbuf *request,
+ struct ofpbuf **reply);
+
+void nl_sock_wait(const struct nl_sock *, short int events);
+
+/* Table dumping. */
+struct nl_dump {
+ struct nl_sock *sock; /* Socket being dumped. */
+ uint32_t seq; /* Expected nlmsg_seq for replies. */
+ struct ofpbuf *buffer; /* Receive buffer currently being iterated. */
+ int status; /* 0=OK, EOF=done, or positive errno value. */
+};
+
+void nl_dump_start(struct nl_dump *, struct nl_sock *,
+ const struct ofpbuf *request);
+bool nl_dump_next(struct nl_dump *, struct ofpbuf *reply);
+int nl_dump_done(struct nl_dump *);
+
+/* Miscellaneous */
+int nl_lookup_genl_family(const char *name, int *number);
+
+#endif /* netlink-socket.h */
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
+#include <sys/types.h>
#include <unistd.h>
#include "coverage.h"
-#include "dynamic-string.h"
#include "netlink-protocol.h"
#include "ofpbuf.h"
-#include "poll-loop.h"
-#include "stress.h"
#include "timeval.h"
-#include "util.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(netlink);
-COVERAGE_DEFINE(netlink_overflow);
-COVERAGE_DEFINE(netlink_received);
-COVERAGE_DEFINE(netlink_recv_retry);
-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 void log_nlmsg(const char *function, int error,
- const void *message, size_t size);
-\f
-/* Netlink sockets. */
-
-struct nl_sock
-{
- int fd;
- uint32_t pid;
-};
-
-/* Next nlmsghdr sequence number.
- *
- * This implementation uses sequence numbers that are unique process-wide, to
- * avoid a hypothetical race: send request, close socket, open new socket that
- * reuses the old socket's PID value, send request on new socket, receive reply
- * from kernel to old socket but with same PID and sequence number. (This race
- * could be avoided other ways, e.g. by preventing PIDs from being quickly
- * reused). */
-static uint32_t next_seq;
-
-static int alloc_pid(uint32_t *);
-static void free_pid(uint32_t);
-
-/* 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.
- *
- * If 'multicast_group' is nonzero, the new socket subscribes to the specified
- * netlink multicast group. (A netlink socket may listen to an arbitrary
- * number of multicast groups, but so far we only need one at a time.)
- *
- * Nonzero 'so_sndbuf' or 'so_rcvbuf' override the kernel default send or
- * receive buffer size, respectively.
- */
-int
-nl_sock_create(int protocol, int multicast_group,
- size_t so_sndbuf, size_t so_rcvbuf, struct nl_sock **sockp)
-{
- struct nl_sock *sock;
- struct sockaddr_nl local, remote;
- int retval = 0;
-
- if (next_seq == 0) {
- /* Pick initial sequence number. */
- next_seq = getpid() ^ time_wall();
- }
-
- *sockp = NULL;
- sock = malloc(sizeof *sock);
- if (sock == NULL) {
- return ENOMEM;
- }
-
- sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
- if (sock->fd < 0) {
- VLOG_ERR("fcntl: %s", strerror(errno));
- goto error;
- }
-
- retval = alloc_pid(&sock->pid);
- if (retval) {
- goto error;
- }
-
- if (so_sndbuf != 0
- && setsockopt(sock->fd, SOL_SOCKET, SO_SNDBUF,
- &so_sndbuf, sizeof so_sndbuf) < 0) {
- VLOG_ERR("setsockopt(SO_SNDBUF,%zu): %s", so_sndbuf, strerror(errno));
- goto error_free_pid;
- }
-
- if (so_rcvbuf != 0
- && setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUF,
- &so_rcvbuf, sizeof so_rcvbuf) < 0) {
- VLOG_ERR("setsockopt(SO_RCVBUF,%zu): %s", so_rcvbuf, strerror(errno));
- goto error_free_pid;
- }
-
- /* Bind local address as our selected pid. */
- memset(&local, 0, sizeof local);
- local.nl_family = AF_NETLINK;
- local.nl_pid = sock->pid;
- if (multicast_group > 0 && multicast_group <= 32) {
- /* This method of joining multicast groups is supported by old kernels,
- * but it only allows 32 multicast groups per protocol. */
- local.nl_groups |= 1ul << (multicast_group - 1);
- }
- if (bind(sock->fd, (struct sockaddr *) &local, sizeof local) < 0) {
- VLOG_ERR("bind(%"PRIu32"): %s", sock->pid, strerror(errno));
- goto error_free_pid;
- }
-
- /* Bind remote address as the kernel (pid 0). */
- 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", strerror(errno));
- goto error_free_pid;
- }
-
- /* Older kernel headers failed to define this macro. We want our programs
- * to support the newer kernel features even if compiled with older
- * headers, so define it ourselves in such a case. */
-#ifndef NETLINK_ADD_MEMBERSHIP
-#define NETLINK_ADD_MEMBERSHIP 1
-#endif
-
- /* This method of joining multicast groups is only supported by newish
- * kernels, but it allows for an arbitrary number of multicast groups. */
- if (multicast_group > 32
- && setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
- &multicast_group, sizeof multicast_group) < 0) {
- VLOG_ERR("setsockopt(NETLINK_ADD_MEMBERSHIP,%d): %s",
- multicast_group, strerror(errno));
- goto error_free_pid;
- }
-
- *sockp = sock;
- return 0;
-
-error_free_pid:
- free_pid(sock->pid);
-error:
- if (retval == 0) {
- retval = errno;
- if (retval == 0) {
- retval = EINVAL;
- }
- }
- if (sock->fd >= 0) {
- close(sock->fd);
- }
- free(sock);
- return retval;
-}
-
-/* Destroys netlink socket 'sock'. */
-void
-nl_sock_destroy(struct nl_sock *sock)
-{
- if (sock) {
- close(sock->fd);
- free_pid(sock->pid);
- free(sock);
- }
-}
-
-/* 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, and
- * nlmsg_pid will be set to 'sock''s pid, 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)
-{
- struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg);
- int error;
-
- nlmsg->nlmsg_len = msg->size;
- 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);
- if (!error) {
- COVERAGE_INC(netlink_sent);
- }
- return error;
-}
-
-/* Tries to send the 'n_iov' chunks of data in 'iov' to the kernel on 'sock' as
- * a single Netlink message. (The message must be fully formed and not require
- * finalization of its nlmsg_len or nlmsg_pid fields.)
- *
- * 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_sendv(struct nl_sock *sock, const struct iovec iov[], size_t n_iov,
- bool wait)
-{
- struct msghdr msg;
- int error;
-
- COVERAGE_INC(netlink_send);
- memset(&msg, 0, sizeof msg);
- msg.msg_iov = (struct iovec *) iov;
- msg.msg_iovlen = n_iov;
- do {
- int retval;
- retval = sendmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
- error = retval < 0 ? errno : 0;
- } while (error == EINTR);
- if (error != EAGAIN) {
- log_nlmsg(__func__, error, iov[0].iov_base, iov[0].iov_len);
- if (!error) {
- COVERAGE_INC(netlink_sent);
- }
- }
- return error;
-}
-
-/* This stress option is useful for testing that OVS properly tolerates
- * -ENOBUFS on NetLink sockets. Such errors are unavoidable because they can
- * occur if the kernel cannot temporarily allocate enough GFP_ATOMIC memory to
- * reply to a request. They can also occur if messages arrive on a multicast
- * channel faster than OVS can process them. */
-STRESS_OPTION(
- netlink_overflow, "simulate netlink socket receive buffer overflow",
- 5, 1, -1, 100);
-
-/* Tries to receive a netlink message from the kernel on 'sock'. If
- * successful, stores the received message into '*bufp' and returns 0. The
- * caller is responsible for destroying the message with ofpbuf_delete(). On
- * failure, returns a positive errno value and stores a null pointer into
- * '*bufp'.
- *
- * If 'wait' is true, nl_sock_recv waits for a message to be ready; otherwise,
- * returns EAGAIN if the 'sock' receive buffer is empty. */
-int
-nl_sock_recv(struct nl_sock *sock, struct ofpbuf **bufp, bool wait)
-{
- uint8_t tmp;
- ssize_t bufsize = 2048;
- ssize_t nbytes, nbytes2;
- struct ofpbuf *buf;
- struct nlmsghdr *nlmsghdr;
- struct iovec iov;
- struct msghdr msg = {
- .msg_name = NULL,
- .msg_namelen = 0,
- .msg_iov = &iov,
- .msg_iovlen = 1,
- .msg_control = NULL,
- .msg_controllen = 0,
- .msg_flags = 0
- };
-
- buf = ofpbuf_new(bufsize);
- *bufp = NULL;
-
-try_again:
- /* Attempt to read the message. We don't know the size of the data
- * yet, so we take a guess at 2048. If we're wrong, we keep trying
- * and doubling the buffer size each time.
- */
- nlmsghdr = ofpbuf_put_uninit(buf, bufsize);
- iov.iov_base = nlmsghdr;
- iov.iov_len = bufsize;
- do {
- nbytes = recvmsg(sock->fd, &msg, (wait ? 0 : MSG_DONTWAIT) | MSG_PEEK);
- } while (nbytes < 0 && errno == EINTR);
- if (nbytes < 0) {
- ofpbuf_delete(buf);
- return errno;
- }
- if (msg.msg_flags & MSG_TRUNC) {
- COVERAGE_INC(netlink_recv_retry);
- bufsize *= 2;
- ofpbuf_reinit(buf, bufsize);
- goto try_again;
- }
- buf->size = nbytes;
-
- /* We successfully read the message, so recv again to clear the queue */
- iov.iov_base = &tmp;
- iov.iov_len = 1;
- do {
- nbytes2 = recvmsg(sock->fd, &msg, MSG_DONTWAIT);
- } while (nbytes2 < 0 && errno == EINTR);
- if (nbytes2 < 0) {
- if (errno == ENOBUFS) {
- /* The kernel is notifying us that a message it tried to send to us
- * was dropped. We have to pass this along to the caller in case
- * it wants to retry a request. So kill the buffer, which we can
- * re-read next time. */
- COVERAGE_INC(netlink_overflow);
- ofpbuf_delete(buf);
- return ENOBUFS;
- } else {
- VLOG_ERR_RL(&rl, "failed to remove nlmsg from socket: %s\n",
- strerror(errno));
- }
- }
- if (nbytes < sizeof *nlmsghdr
- || nlmsghdr->nlmsg_len < sizeof *nlmsghdr
- || nlmsghdr->nlmsg_len > nbytes) {
- VLOG_ERR_RL(&rl, "received invalid nlmsg (%zd bytes < %d)",
- bufsize, NLMSG_HDRLEN);
- ofpbuf_delete(buf);
- return EPROTO;
- }
-
- if (STRESS(netlink_overflow)) {
- ofpbuf_delete(buf);
- return ENOBUFS;
- }
-
- *bufp = buf;
- log_nlmsg(__func__, 0, buf->data, buf->size);
- COVERAGE_INC(netlink_received);
-
- return 0;
-}
-
-/* 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.
- *
- * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will
- * be set to 'sock''s pid, before the message is sent. 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)
-{
- uint32_t seq = nl_msg_nlmsghdr(request)->nlmsg_seq;
- struct nlmsghdr *nlmsghdr;
- struct ofpbuf *reply;
- int retval;
-
- if (replyp) {
- *replyp = NULL;
- }
-
- /* Ensure that we get a reply even if this message doesn't ordinarily call
- * for one. */
- nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_ACK;
-
-send:
- retval = nl_sock_send(sock, request, true);
- if (retval) {
- return retval;
- }
-
-recv:
- retval = nl_sock_recv(sock, &reply, true);
- if (retval) {
- if (retval == ENOBUFS) {
- COVERAGE_INC(netlink_overflow);
- VLOG_DBG_RL(&rl, "receive buffer overflow, resending request");
- goto send;
- } else {
- return retval;
- }
- }
- nlmsghdr = nl_msg_nlmsghdr(reply);
- if (seq != nlmsghdr->nlmsg_seq) {
- VLOG_DBG_RL(&rl, "ignoring seq %"PRIu32" != expected %"PRIu32,
- nl_msg_nlmsghdr(reply)->nlmsg_seq, seq);
- ofpbuf_delete(reply);
- goto recv;
- }
-
- /* If the reply is an error, discard the reply and return the error code.
- *
- * Except: if the reply is just an acknowledgement (error code of 0), and
- * the caller is interested in the reply (replyp != NULL), pass the reply
- * up to the caller. Otherwise the caller will get a return value of 0
- * and null '*replyp', which makes unwary callers likely to segfault. */
- if (nl_msg_nlmsgerr(reply, &retval) && (retval || !replyp)) {
- ofpbuf_delete(reply);
- if (retval) {
- VLOG_DBG_RL(&rl, "received NAK error=%d (%s)",
- retval, strerror(retval));
- }
- return retval != EAGAIN ? retval : EPROTO;
- }
-
- if (replyp) {
- *replyp = reply;
- } else {
- ofpbuf_delete(reply);
- }
- return 0;
-}
-
-/* Starts a Netlink "dump" operation, by sending 'request' to the kernel via
- * 'sock', 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 'sock''s pid, before the message is sent. NLM_F_DUMP and
- * NLM_F_ACK will be set in nlmsg_flags.
- *
- * The properties of Netlink make dump operations reliable as long as all of
- * the following are true:
- *
- * - At most a single dump is in progress at a time on a given nl_sock.
- *
- * - The nl_sock is not subscribed to any multicast groups.
- *
- * - The nl_sock is not used to send any other messages before the dump
- * operation is complete.
- *
- * 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'. The caller must not
- * close 'sock' before it completes the dump operation (by calling
- * nl_dump_done()).
- */
-void
-nl_dump_start(struct nl_dump *dump,
- struct nl_sock *sock, const struct ofpbuf *request)
-{
- struct nlmsghdr *nlmsghdr = nl_msg_nlmsghdr(request);
- nlmsghdr->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK;
- dump->seq = nlmsghdr->nlmsg_seq;
- dump->sock = sock;
- dump->status = nl_sock_send(sock, request, true);
- dump->buffer = NULL;
-}
-
-/* Helper function for nl_dump_next(). */
-static int
-nl_dump_recv(struct nl_dump *dump, struct ofpbuf **bufferp)
-{
- struct nlmsghdr *nlmsghdr;
- struct ofpbuf *buffer;
- int retval;
-
- retval = nl_sock_recv(dump->sock, bufferp, true);
- if (retval) {
- return retval == EINTR ? EAGAIN : retval;
- }
- buffer = *bufferp;
-
- nlmsghdr = nl_msg_nlmsghdr(buffer);
- if (dump->seq != nlmsghdr->nlmsg_seq) {
- VLOG_DBG_RL(&rl, "ignoring seq %"PRIu32" != expected %"PRIu32,
- nlmsghdr->nlmsg_seq, dump->seq);
- return EAGAIN;
- }
-
- if (nl_msg_nlmsgerr(buffer, &retval)) {
- VLOG_INFO_RL(&rl, "netlink dump request error (%s)",
- 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;
- }
-
- if (dump->buffer && !dump->buffer->size) {
- ofpbuf_delete(dump->buffer);
- dump->buffer = NULL;
- }
- while (!dump->buffer) {
- int retval = nl_dump_recv(dump, &dump->buffer);
- if (retval) {
- ofpbuf_delete(dump->buffer);
- dump->buffer = NULL;
- 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. */
- while (!dump->status) {
- struct ofpbuf reply;
- if (!nl_dump_next(dump, &reply)) {
- assert(dump->status);
- }
- }
-
- ofpbuf_delete(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);
-}
-\f
-/* Netlink messages. */
-
/* Returns the nlmsghdr at the head of 'msg'.
*
* 'msg' must be at least as large as a nlmsghdr. */
ofpbuf_prealloc_tailroom(msg, NLMSG_ALIGN(size));
}
+static uint32_t
+get_nlmsg_seq(void)
+{
+ /* Next nlmsghdr sequence number.
+ *
+ * This implementation uses sequence numbers that are unique process-wide,
+ * to avoid a hypothetical race: send request, close socket, open new
+ * socket that reuses the old socket's PID value, send request on new
+ * socket, receive reply from kernel to old socket but with same PID and
+ * sequence number. (This race could be avoided other ways, e.g. by
+ * preventing PIDs from being quickly reused). */
+ static uint32_t next_seq;
+
+ if (next_seq == 0) {
+ /* Pick initial sequence number. */
+ next_seq = getpid() ^ time_wall();
+ }
+ return next_seq++;
+}
+
/* Puts a nlmsghdr at the beginning of 'msg', which must be initially empty.
* Uses the given 'type' and 'flags'. 'expected_payload' should be
* an estimate of the number of payload bytes to be supplied; if the size of
nlmsghdr->nlmsg_len = 0;
nlmsghdr->nlmsg_type = type;
nlmsghdr->nlmsg_flags = flags;
- nlmsghdr->nlmsg_seq = ++next_seq;
+ nlmsghdr->nlmsg_seq = get_nlmsg_seq();
nlmsghdr->nlmsg_pid = 0;
}
nl_attr_get_nested(nla, &buf);
return nl_policy_parse(&buf, 0, policy, attrs, n_attrs);
}
-\f
-/* Miscellaneous. */
-
-static const struct nl_policy family_policy[CTRL_ATTR_MAX + 1] = {
- [CTRL_ATTR_FAMILY_ID] = {.type = NL_A_U16},
-};
-
-static int do_lookup_genl_family(const char *name)
-{
- struct nl_sock *sock;
- struct ofpbuf request, *reply;
- struct nlattr *attrs[ARRAY_SIZE(family_policy)];
- int retval;
-
- retval = nl_sock_create(NETLINK_GENERIC, 0, 0, 0, &sock);
- if (retval) {
- return -retval;
- }
-
- 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);
- retval = nl_sock_transact(sock, &request, &reply);
- ofpbuf_uninit(&request);
- if (retval) {
- nl_sock_destroy(sock);
- return -retval;
- }
-
- if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN,
- family_policy, attrs, ARRAY_SIZE(family_policy))) {
- nl_sock_destroy(sock);
- ofpbuf_delete(reply);
- return -EPROTO;
- }
-
- retval = nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]);
- if (retval == 0) {
- retval = -EPROTO;
- }
- nl_sock_destroy(sock);
- ofpbuf_delete(reply);
- return retval;
-}
-
-/* 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) {
- *number = do_lookup_genl_family(name);
- assert(*number != 0);
- }
- return *number > 0 ? 0 : -*number;
-}
-\f
-/* Netlink PID.
- *
- * Every Netlink socket must be bound to a unique 32-bit PID. By convention,
- * programs that have a single Netlink socket use their Unix process ID as PID,
- * and programs with multiple Netlink sockets add a unique per-socket
- * identifier in the bits above the Unix process ID.
- *
- * The kernel has Netlink PID 0.
- */
-
-/* Parameters for how many bits in the PID should come from the Unix process ID
- * and how many unique per-socket. */
-#define SOCKET_BITS 10
-#define MAX_SOCKETS (1u << SOCKET_BITS)
-
-#define PROCESS_BITS (32 - SOCKET_BITS)
-#define MAX_PROCESSES (1u << PROCESS_BITS)
-#define PROCESS_MASK ((uint32_t) (MAX_PROCESSES - 1))
-
-/* Bit vector of unused socket identifiers. */
-static uint32_t avail_sockets[ROUND_UP(MAX_SOCKETS, 32)];
-
-/* Allocates and returns a new Netlink PID. */
-static int
-alloc_pid(uint32_t *pid)
-{
- int i;
-
- for (i = 0; i < MAX_SOCKETS; i++) {
- if ((avail_sockets[i / 32] & (1u << (i % 32))) == 0) {
- avail_sockets[i / 32] |= 1u << (i % 32);
- *pid = (getpid() & PROCESS_MASK) | (i << PROCESS_BITS);
- return 0;
- }
- }
- VLOG_ERR("netlink pid space exhausted");
- return ENOBUFS;
-}
-
-/* Makes the specified 'pid' available for reuse. */
-static void
-free_pid(uint32_t pid)
-{
- int sock = pid >> PROCESS_BITS;
- assert(avail_sockets[sock / 32] & (1u << (sock % 32)));
- avail_sockets[sock / 32] &= ~(1u << (sock % 32));
-}
-\f
-static void
-nlmsghdr_to_string(const struct nlmsghdr *h, 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 {
- 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"(%d:%d))",
- h->nlmsg_seq, h->nlmsg_pid,
- (int) (h->nlmsg_pid & PROCESS_MASK),
- (int) (h->nlmsg_pid >> PROCESS_BITS));
-}
-
-static char *
-nlmsg_to_string(const struct ofpbuf *buffer)
-{
- struct ds ds = DS_EMPTY_INITIALIZER;
- const struct nlmsghdr *h = ofpbuf_at(buffer, 0, NLMSG_HDRLEN);
- if (h) {
- nlmsghdr_to_string(h, &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)", strerror(-e->error));
- }
- ds_put_cstr(&ds, ", in-reply-to(");
- nlmsghdr_to_string(&e->msg, &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)", strerror(-*error));
- }
- ds_put_cstr(&ds, ")");
- } else {
- ds_put_cstr(&ds, " done(truncated)");
- }
- }
- } 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)
-{
- struct ofpbuf buffer;
- char *nlmsg;
-
- if (!VLOG_IS_DBG_ENABLED()) {
- return;
- }
-
- ofpbuf_use_const(&buffer, message, size);
- nlmsg = nlmsg_to_string(&buffer);
- VLOG_DBG_RL(&rl, "%s (%s): %s", function, strerror(error), nlmsg);
- free(nlmsg);
-}
-
#ifndef NETLINK_H
#define NETLINK_H 1
-/* Netlink interface.
+/* Netlink message helpers.
*
* Netlink is a datagram-based network protocol primarily for communication
* between user processes and the kernel, and mainly on Linux. Netlink is
* specified in RFC 3549, "Linux Netlink as an IP Services Protocol".
*
* Netlink is not suitable for use in physical networks of heterogeneous
- * machines because host byte order is used throughout. */
+ * machines because host byte order is used throughout.
+ *
+ * This header file defines helper functions for working with Netlink messages.
+ * For Netlink protocol definitions, see netlink-protocol.h. For
+ * Linux-specific definitions for Netlink sockets, see netlink-socket.h.
+ */
#include <stdbool.h>
-#include <sys/uio.h>
+#include <stddef.h>
#include <stdint.h>
struct ofpbuf;
-struct nl_sock;
struct nlattr;
-/* Netlink sockets. */
-
-int nl_sock_create(int protocol, int multicast_group,
- size_t so_sndbuf, size_t so_rcvbuf,
- struct nl_sock **);
-void nl_sock_destroy(struct nl_sock *);
-
-int nl_sock_send(struct nl_sock *, const struct ofpbuf *, bool wait);
-int nl_sock_sendv(struct nl_sock *sock, const struct iovec iov[], size_t n_iov,
- bool wait);
-int nl_sock_recv(struct nl_sock *, struct ofpbuf **, bool wait);
-int nl_sock_transact(struct nl_sock *, const struct ofpbuf *request,
- struct ofpbuf **reply);
-
-void nl_sock_wait(const struct nl_sock *, short int events);
-
-/* Table dumping. */
-struct nl_dump {
- struct nl_sock *sock; /* Socket being dumped. */
- uint32_t seq; /* Expected nlmsg_seq for replies. */
- struct ofpbuf *buffer; /* Receive buffer currently being iterated. */
- int status; /* 0=OK, EOF=done, or positive errno value. */
-};
-
-void nl_dump_start(struct nl_dump *, struct nl_sock *,
- const struct ofpbuf *request);
-bool nl_dump_next(struct nl_dump *, struct ofpbuf *reply);
-int nl_dump_done(struct nl_dump *);
-\f
-/* Netlink messages. */
-
/* Accessing headers and data. */
struct nlmsghdr *nl_msg_nlmsghdr(const struct ofpbuf *);
struct genlmsghdr *nl_msg_genlmsghdr(const struct ofpbuf *);
struct nlattr *[], size_t n_attrs);
bool nl_parse_nested(const struct nlattr *, const struct nl_policy[],
struct nlattr *[], size_t n_attrs);
-\f
-/* Miscellaneous. */
-
-int nl_lookup_genl_family(const char *name, int *number);
#endif /* netlink.h */
#include "coverage.h"
#include "netlink.h"
+#include "netlink-socket.h"
#include "ofpbuf.h"
#include "vlog.h"
#include <stddef.h>
#include <linux/rtnetlink.h>
#include "netlink.h"
+#include "netlink-socket.h"
#include "ofpbuf.h"
#include "poll-loop.h"
#include "timeval.h"
#include "leak-checker.h"
#include "netdev.h"
#include "netlink.h"
+#include "netlink-socket.h"
#include "ofpbuf.h"
#include "openvswitch/brcompat-netlink.h"
#include "ovsdb-idl.h"
#include "dynamic-string.h"
#include "hash.h"
#include "netlink-protocol.h"
+#include "netlink-socket.h"
#include "netlink.h"
#include "ofpbuf.h"
#include "openvswitch/brcompat-netlink.h"
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