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netlink: Split into generic and Linux-specific parts.
The parts of the netlink module that are related to sockets are Linux-specific, since only Linux has AF_NETLINK sockets. The rest can be built anywhere. This commit breaks them into two modules, and builds the generic one on all platforms. Acked-by: Jesse Gross <jesse@nicira.com>
This commit is contained in:
Ben Pfaff
814
lib/netlink-socket.c
Normal file
814
lib/netlink-socket.c
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@@ -0,0 +1,814 @@
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/*
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* Copyright (c) 2008, 2009, 2010 Nicira Networks.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include "netlink-socket.h"
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#include <assert.h>
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#include <errno.h>
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#include <inttypes.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "coverage.h"
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#include "dynamic-string.h"
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#include "netlink.h"
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#include "netlink-protocol.h"
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#include "ofpbuf.h"
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#include "poll-loop.h"
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#include "stress.h"
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#include "vlog.h"
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VLOG_DEFINE_THIS_MODULE(netlink_socket);
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COVERAGE_DEFINE(netlink_overflow);
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COVERAGE_DEFINE(netlink_received);
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COVERAGE_DEFINE(netlink_recv_retry);
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COVERAGE_DEFINE(netlink_send);
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COVERAGE_DEFINE(netlink_sent);
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/* Linux header file confusion causes this to be undefined. */
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#ifndef SOL_NETLINK
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#define SOL_NETLINK 270
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#endif
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/* A single (bad) Netlink message can in theory dump out many, many log
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* messages, so the burst size is set quite high here to avoid missing useful
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* information. Also, at high logging levels we log *all* Netlink messages. */
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static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 600);
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static void log_nlmsg(const char *function, int error,
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const void *message, size_t size);
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/* Netlink sockets. */
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struct nl_sock
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{
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int fd;
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uint32_t pid;
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};
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static int alloc_pid(uint32_t *);
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static void free_pid(uint32_t);
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/* Creates a new netlink socket for the given netlink 'protocol'
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* (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the
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* new socket if successful, otherwise returns a positive errno value.
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*
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* If 'multicast_group' is nonzero, the new socket subscribes to the specified
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* netlink multicast group. (A netlink socket may listen to an arbitrary
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* number of multicast groups, but so far we only need one at a time.)
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*
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* Nonzero 'so_sndbuf' or 'so_rcvbuf' override the kernel default send or
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* receive buffer size, respectively.
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*/
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int
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nl_sock_create(int protocol, int multicast_group,
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size_t so_sndbuf, size_t so_rcvbuf, struct nl_sock **sockp)
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{
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struct nl_sock *sock;
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struct sockaddr_nl local, remote;
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int retval = 0;
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*sockp = NULL;
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sock = malloc(sizeof *sock);
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if (sock == NULL) {
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return ENOMEM;
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}
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sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
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if (sock->fd < 0) {
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VLOG_ERR("fcntl: %s", strerror(errno));
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goto error;
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}
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retval = alloc_pid(&sock->pid);
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if (retval) {
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goto error;
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}
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if (so_sndbuf != 0
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&& setsockopt(sock->fd, SOL_SOCKET, SO_SNDBUF,
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&so_sndbuf, sizeof so_sndbuf) < 0) {
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VLOG_ERR("setsockopt(SO_SNDBUF,%zu): %s", so_sndbuf, strerror(errno));
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goto error_free_pid;
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}
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if (so_rcvbuf != 0
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&& setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUF,
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&so_rcvbuf, sizeof so_rcvbuf) < 0) {
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VLOG_ERR("setsockopt(SO_RCVBUF,%zu): %s", so_rcvbuf, strerror(errno));
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goto error_free_pid;
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}
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/* Bind local address as our selected pid. */
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memset(&local, 0, sizeof local);
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local.nl_family = AF_NETLINK;
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local.nl_pid = sock->pid;
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if (multicast_group > 0 && multicast_group <= 32) {
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/* This method of joining multicast groups is supported by old kernels,
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* but it only allows 32 multicast groups per protocol. */
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local.nl_groups |= 1ul << (multicast_group - 1);
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}
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if (bind(sock->fd, (struct sockaddr *) &local, sizeof local) < 0) {
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VLOG_ERR("bind(%"PRIu32"): %s", sock->pid, strerror(errno));
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goto error_free_pid;
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}
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/* Bind remote address as the kernel (pid 0). */
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memset(&remote, 0, sizeof remote);
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remote.nl_family = AF_NETLINK;
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remote.nl_pid = 0;
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if (connect(sock->fd, (struct sockaddr *) &remote, sizeof remote) < 0) {
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VLOG_ERR("connect(0): %s", strerror(errno));
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goto error_free_pid;
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}
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/* Older kernel headers failed to define this macro. We want our programs
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* to support the newer kernel features even if compiled with older
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* headers, so define it ourselves in such a case. */
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#ifndef NETLINK_ADD_MEMBERSHIP
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#define NETLINK_ADD_MEMBERSHIP 1
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#endif
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/* This method of joining multicast groups is only supported by newish
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* kernels, but it allows for an arbitrary number of multicast groups. */
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if (multicast_group > 32
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&& setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
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&multicast_group, sizeof multicast_group) < 0) {
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VLOG_ERR("setsockopt(NETLINK_ADD_MEMBERSHIP,%d): %s",
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multicast_group, strerror(errno));
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goto error_free_pid;
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}
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*sockp = sock;
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return 0;
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error_free_pid:
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free_pid(sock->pid);
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error:
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if (retval == 0) {
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retval = errno;
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if (retval == 0) {
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retval = EINVAL;
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}
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}
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if (sock->fd >= 0) {
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close(sock->fd);
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}
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free(sock);
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return retval;
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}
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/* Destroys netlink socket 'sock'. */
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void
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nl_sock_destroy(struct nl_sock *sock)
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{
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if (sock) {
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close(sock->fd);
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free_pid(sock->pid);
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free(sock);
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}
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}
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/* Tries to send 'msg', which must contain a Netlink message, to the kernel on
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* 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, and
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* nlmsg_pid will be set to 'sock''s pid, before the message is sent.
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*
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* Returns 0 if successful, otherwise a positive errno value. If
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* 'wait' is true, then the send will wait until buffer space is ready;
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* otherwise, returns EAGAIN if the 'sock' send buffer is full. */
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int
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nl_sock_send(struct nl_sock *sock, const struct ofpbuf *msg, bool wait)
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{
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struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg);
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int error;
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nlmsg->nlmsg_len = msg->size;
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nlmsg->nlmsg_pid = sock->pid;
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do {
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int retval;
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retval = send(sock->fd, msg->data, msg->size, wait ? 0 : MSG_DONTWAIT);
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error = retval < 0 ? errno : 0;
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} while (error == EINTR);
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log_nlmsg(__func__, error, msg->data, msg->size);
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if (!error) {
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COVERAGE_INC(netlink_sent);
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}
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return error;
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}
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/* Tries to send the 'n_iov' chunks of data in 'iov' to the kernel on 'sock' as
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* a single Netlink message. (The message must be fully formed and not require
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* finalization of its nlmsg_len or nlmsg_pid fields.)
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*
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* Returns 0 if successful, otherwise a positive errno value. If 'wait' is
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* true, then the send will wait until buffer space is ready; otherwise,
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* returns EAGAIN if the 'sock' send buffer is full. */
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int
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nl_sock_sendv(struct nl_sock *sock, const struct iovec iov[], size_t n_iov,
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bool wait)
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{
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struct msghdr msg;
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int error;
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COVERAGE_INC(netlink_send);
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memset(&msg, 0, sizeof msg);
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msg.msg_iov = (struct iovec *) iov;
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msg.msg_iovlen = n_iov;
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do {
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int retval;
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retval = sendmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
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error = retval < 0 ? errno : 0;
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} while (error == EINTR);
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if (error != EAGAIN) {
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log_nlmsg(__func__, error, iov[0].iov_base, iov[0].iov_len);
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if (!error) {
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COVERAGE_INC(netlink_sent);
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}
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}
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return error;
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}
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/* This stress option is useful for testing that OVS properly tolerates
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* -ENOBUFS on NetLink sockets. Such errors are unavoidable because they can
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* occur if the kernel cannot temporarily allocate enough GFP_ATOMIC memory to
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* reply to a request. They can also occur if messages arrive on a multicast
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* channel faster than OVS can process them. */
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STRESS_OPTION(
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netlink_overflow, "simulate netlink socket receive buffer overflow",
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5, 1, -1, 100);
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/* Tries to receive a netlink message from the kernel on 'sock'. If
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* successful, stores the received message into '*bufp' and returns 0. The
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* caller is responsible for destroying the message with ofpbuf_delete(). On
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* failure, returns a positive errno value and stores a null pointer into
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* '*bufp'.
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*
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* If 'wait' is true, nl_sock_recv waits for a message to be ready; otherwise,
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* returns EAGAIN if the 'sock' receive buffer is empty. */
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int
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nl_sock_recv(struct nl_sock *sock, struct ofpbuf **bufp, bool wait)
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{
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uint8_t tmp;
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ssize_t bufsize = 2048;
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ssize_t nbytes, nbytes2;
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struct ofpbuf *buf;
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struct nlmsghdr *nlmsghdr;
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struct iovec iov;
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struct msghdr msg = {
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.msg_name = NULL,
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.msg_namelen = 0,
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.msg_iov = &iov,
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.msg_iovlen = 1,
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.msg_control = NULL,
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.msg_controllen = 0,
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.msg_flags = 0
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};
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buf = ofpbuf_new(bufsize);
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*bufp = NULL;
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try_again:
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/* Attempt to read the message. We don't know the size of the data
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* yet, so we take a guess at 2048. If we're wrong, we keep trying
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* and doubling the buffer size each time.
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*/
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nlmsghdr = ofpbuf_put_uninit(buf, bufsize);
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iov.iov_base = nlmsghdr;
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iov.iov_len = bufsize;
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do {
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nbytes = recvmsg(sock->fd, &msg, (wait ? 0 : MSG_DONTWAIT) | MSG_PEEK);
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} while (nbytes < 0 && errno == EINTR);
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if (nbytes < 0) {
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ofpbuf_delete(buf);
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return errno;
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}
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if (msg.msg_flags & MSG_TRUNC) {
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COVERAGE_INC(netlink_recv_retry);
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bufsize *= 2;
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ofpbuf_reinit(buf, bufsize);
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goto try_again;
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}
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buf->size = nbytes;
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/* We successfully read the message, so recv again to clear the queue */
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iov.iov_base = &tmp;
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iov.iov_len = 1;
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do {
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nbytes2 = recvmsg(sock->fd, &msg, MSG_DONTWAIT);
|
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} while (nbytes2 < 0 && errno == EINTR);
|
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if (nbytes2 < 0) {
|
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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. */
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||||
COVERAGE_INC(netlink_overflow);
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||||
ofpbuf_delete(buf);
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||||
return ENOBUFS;
|
||||
} else {
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||||
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);
|
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ofpbuf_delete(buf);
|
||||
return EPROTO;
|
||||
}
|
||||
|
||||
if (STRESS(netlink_overflow)) {
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||||
ofpbuf_delete(buf);
|
||||
return ENOBUFS;
|
||||
}
|
||||
|
||||
*bufp = buf;
|
||||
log_nlmsg(__func__, 0, buf->data, buf->size);
|
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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);
|
||||
}
|
||||
|
||||
/* 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;
|
||||
}
|
||||
|
||||
/* 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));
|
||||
}
|
||||
|
||||
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);
|
||||
}
|
||||
|
||||
|
||||
Reference in New Issue
Block a user