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ovs/lib/netlink-socket.c
Xiao Liang fd016ae3fb lib: Move lib/poll-loop.h to include/openvswitch 
Poll-loop is the core to implement main loop. It should be available in
libopenvswitch.

Signed-off-by: Xiao Liang <shaw.leon@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
2017-11-03 10:47:55 -07:00

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/*
* Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2016 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "netlink-socket.h"
#include <errno.h>
#include <inttypes.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include "coverage.h"
#include "openvswitch/dynamic-string.h"
#include "hash.h"
#include "openvswitch/hmap.h"
#include "netlink.h"
#include "netlink-protocol.h"
#include "odp-netlink.h"
#include "openvswitch/ofpbuf.h"
#include "ovs-thread.h"
#include "openvswitch/poll-loop.h"
#include "seq.h"
#include "socket-util.h"
#include "util.h"
#include "openvswitch/vlog.h"
VLOG_DEFINE_THIS_MODULE(netlink_socket);
COVERAGE_DEFINE(netlink_overflow);
COVERAGE_DEFINE(netlink_received);
COVERAGE_DEFINE(netlink_recv_jumbo);
COVERAGE_DEFINE(netlink_sent);
/* Linux header file confusion causes this to be undefined. */
#ifndef SOL_NETLINK
#define SOL_NETLINK 270
#endif
/* A single (bad) Netlink message can in theory dump out many, many log
* messages, so the burst size is set quite high here to avoid missing useful
* information. Also, at high logging levels we log *all* Netlink messages. */
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 600);
static uint32_t nl_sock_allocate_seq(struct nl_sock *, unsigned int n);
static void log_nlmsg(const char *function, int error,
const void *message, size_t size, int protocol);
#ifdef _WIN32
static int get_sock_pid_from_kernel(struct nl_sock *sock);
static int set_sock_property(struct nl_sock *sock);
static int nl_sock_transact(struct nl_sock *sock, const struct ofpbuf *request,
struct ofpbuf **replyp);
/* In the case DeviceIoControl failed and GetLastError returns with
* ERROR_NOT_FOUND means we lost communication with the kernel device.
* CloseHandle will fail because the handle in 'theory' does not exist.
* The only remaining option is to crash and allow the service to be restarted
* via service manager. This is the only way to close the handle from both
* userspace and kernel. */
void
lost_communication(DWORD last_err)
{
if (last_err == ERROR_NOT_FOUND) {
ovs_abort(0, "lost communication with the kernel device");
}
}
#endif
/* Netlink sockets. */
struct nl_sock {
#ifdef _WIN32
HANDLE handle;
OVERLAPPED overlapped;
DWORD read_ioctl;
#else
int fd;
#endif
uint32_t next_seq;
uint32_t pid;
int protocol;
unsigned int rcvbuf; /* Receive buffer size (SO_RCVBUF). */
};
/* Compile-time limit on iovecs, so that we can allocate a maximum-size array
* of iovecs on the stack. */
#define MAX_IOVS 128
/* Maximum number of iovecs that may be passed to sendmsg, capped at a
* minimum of _XOPEN_IOV_MAX (16) and a maximum of MAX_IOVS.
*
* Initialized by nl_sock_create(). */
static int max_iovs;
static int nl_pool_alloc(int protocol, struct nl_sock **sockp);
static void nl_pool_release(struct nl_sock *);
/* Creates a new netlink socket for the given netlink 'protocol'
* (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the
* new socket if successful, otherwise returns a positive errno value. */
int
nl_sock_create(int protocol, struct nl_sock **sockp)
{
static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
struct nl_sock *sock;
#ifndef _WIN32
struct sockaddr_nl local, remote;
#endif
socklen_t local_size;
int rcvbuf;
int retval = 0;
if (ovsthread_once_start(&once)) {
int save_errno = errno;
errno = 0;
max_iovs = sysconf(_SC_UIO_MAXIOV);
if (max_iovs < _XOPEN_IOV_MAX) {
if (max_iovs == -1 && errno) {
VLOG_WARN("sysconf(_SC_UIO_MAXIOV): %s", ovs_strerror(errno));
}
max_iovs = _XOPEN_IOV_MAX;
} else if (max_iovs > MAX_IOVS) {
max_iovs = MAX_IOVS;
}
errno = save_errno;
ovsthread_once_done(&once);
}
*sockp = NULL;
sock = xmalloc(sizeof *sock);
#ifdef _WIN32
sock->overlapped.hEvent = NULL;
sock->handle = CreateFile(OVS_DEVICE_NAME_USER,
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL, OPEN_EXISTING,
FILE_FLAG_OVERLAPPED, NULL);
if (sock->handle == INVALID_HANDLE_VALUE) {
VLOG_ERR("fcntl: %s", ovs_lasterror_to_string());
goto error;
}
memset(&sock->overlapped, 0, sizeof sock->overlapped);
sock->overlapped.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
if (sock->overlapped.hEvent == NULL) {
VLOG_ERR("fcntl: %s", ovs_lasterror_to_string());
goto error;
}
/* Initialize the type/ioctl to Generic */
sock->read_ioctl = OVS_IOCTL_READ;
#else
sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
if (sock->fd < 0) {
VLOG_ERR("fcntl: %s", ovs_strerror(errno));
goto error;
}
#endif
sock->protocol = protocol;
sock->next_seq = 1;
rcvbuf = 1024 * 1024;
#ifdef _WIN32
sock->rcvbuf = rcvbuf;
retval = get_sock_pid_from_kernel(sock);
if (retval != 0) {
goto error;
}
retval = set_sock_property(sock);
if (retval != 0) {
goto error;
}
#else
if (setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUFFORCE,
&rcvbuf, sizeof rcvbuf)) {
/* Only root can use SO_RCVBUFFORCE. Everyone else gets EPERM.
* Warn only if the failure is therefore unexpected. */
if (errno != EPERM) {
VLOG_WARN_RL(&rl, "setting %d-byte socket receive buffer failed "
"(%s)", rcvbuf, ovs_strerror(errno));
}
}
retval = get_socket_rcvbuf(sock->fd);
if (retval < 0) {
retval = -retval;
goto error;
}
sock->rcvbuf = retval;
retval = 0;
/* Connect to kernel (pid 0) as remote address. */
memset(&remote, 0, sizeof remote);
remote.nl_family = AF_NETLINK;
remote.nl_pid = 0;
if (connect(sock->fd, (struct sockaddr *) &remote, sizeof remote) < 0) {
VLOG_ERR("connect(0): %s", ovs_strerror(errno));
goto error;
}
/* Obtain pid assigned by kernel. */
local_size = sizeof local;
if (getsockname(sock->fd, (struct sockaddr *) &local, &local_size) < 0) {
VLOG_ERR("getsockname: %s", ovs_strerror(errno));
goto error;
}
if (local_size < sizeof local || local.nl_family != AF_NETLINK) {
VLOG_ERR("getsockname returned bad Netlink name");
retval = EINVAL;
goto error;
}
sock->pid = local.nl_pid;
#endif
*sockp = sock;
return 0;
error:
if (retval == 0) {
retval = errno;
if (retval == 0) {
retval = EINVAL;
}
}
#ifdef _WIN32
if (sock->overlapped.hEvent) {
CloseHandle(sock->overlapped.hEvent);
}
if (sock->handle != INVALID_HANDLE_VALUE) {
CloseHandle(sock->handle);
}
#else
if (sock->fd >= 0) {
close(sock->fd);
}
#endif
free(sock);
return retval;
}
/* Creates a new netlink socket for the same protocol as 'src'. Returns 0 and
* sets '*sockp' to the new socket if successful, otherwise returns a positive
* errno value. */
int
nl_sock_clone(const struct nl_sock *src, struct nl_sock **sockp)
{
return nl_sock_create(src->protocol, sockp);
}
/* Destroys netlink socket 'sock'. */
void
nl_sock_destroy(struct nl_sock *sock)
{
if (sock) {
#ifdef _WIN32
if (sock->overlapped.hEvent) {
CloseHandle(sock->overlapped.hEvent);
}
CloseHandle(sock->handle);
#else
close(sock->fd);
#endif
free(sock);
}
}
#ifdef _WIN32
/* Reads the pid for 'sock' generated in the kernel datapath. The function
* uses a separate IOCTL instead of a transaction semantic to avoid unnecessary
* message overhead. */
static int
get_sock_pid_from_kernel(struct nl_sock *sock)
{
uint32_t pid = 0;
int retval = 0;
DWORD bytes = 0;
if (!DeviceIoControl(sock->handle, OVS_IOCTL_GET_PID,
NULL, 0, &pid, sizeof(pid),
&bytes, NULL)) {
lost_communication(GetLastError());
retval = EINVAL;
} else {
if (bytes < sizeof(pid)) {
retval = EINVAL;
} else {
sock->pid = pid;
}
}
return retval;
}
/* Used for setting and managing socket properties in userspace and kernel.
* Currently two attributes are tracked - pid and protocol
* protocol - supplied by userspace based on the netlink family. Windows uses
* this property to set the value in kernel datapath.
* eg: (NETLINK_GENERIC/ NETLINK_NETFILTER)
* pid - generated by windows kernel and set in userspace. The property
* is not modified.
* Also verify if Protocol and PID in Kernel reflects the values in userspace
* */
static int
set_sock_property(struct nl_sock *sock)
{
static const struct nl_policy ovs_socket_policy[] = {
[OVS_NL_ATTR_SOCK_PROTO] = { .type = NL_A_BE32, .optional = true },
[OVS_NL_ATTR_SOCK_PID] = { .type = NL_A_BE32, .optional = true }
};
struct ofpbuf request, *reply;
struct ovs_header *ovs_header;
struct nlattr *attrs[ARRAY_SIZE(ovs_socket_policy)];
int retval = 0;
int error;
ofpbuf_init(&request, 0);
nl_msg_put_genlmsghdr(&request, 0, OVS_WIN_NL_CTRL_FAMILY_ID, 0,
OVS_CTRL_CMD_SOCK_PROP, OVS_WIN_CONTROL_VERSION);
ovs_header = ofpbuf_put_uninit(&request, sizeof *ovs_header);
ovs_header->dp_ifindex = 0;
nl_msg_put_be32(&request, OVS_NL_ATTR_SOCK_PROTO, sock->protocol);
/* pid is already set as part of get_sock_pid_from_kernel()
* This is added to maintain consistency
*/
nl_msg_put_be32(&request, OVS_NL_ATTR_SOCK_PID, sock->pid);
error = nl_sock_transact(sock, &request, &reply);
ofpbuf_uninit(&request);
if (error) {
retval = EINVAL;
}
if (!nl_policy_parse(reply,
NLMSG_HDRLEN + GENL_HDRLEN + sizeof *ovs_header,
ovs_socket_policy, attrs,
ARRAY_SIZE(ovs_socket_policy))) {
ofpbuf_delete(reply);
retval = EINVAL;
}
/* Verify if the properties are setup properly */
if (attrs[OVS_NL_ATTR_SOCK_PROTO]) {
int protocol = nl_attr_get_be32(attrs[OVS_NL_ATTR_SOCK_PROTO]);
if (protocol != sock->protocol) {
VLOG_ERR("Invalid protocol returned:%d expected:%d",
protocol, sock->protocol);
retval = EINVAL;
}
}
if (attrs[OVS_NL_ATTR_SOCK_PID]) {
int pid = nl_attr_get_be32(attrs[OVS_NL_ATTR_SOCK_PID]);
if (pid != sock->pid) {
VLOG_ERR("Invalid pid returned:%d expected:%d",
pid, sock->pid);
retval = EINVAL;
}
}
return retval;
}
#endif /* _WIN32 */
#ifdef _WIN32
static int __inline
nl_sock_mcgroup(struct nl_sock *sock, unsigned int multicast_group, bool join)
{
struct ofpbuf request;
uint64_t request_stub[128];
struct ovs_header *ovs_header;
struct nlmsghdr *nlmsg;
int error;
ofpbuf_use_stub(&request, request_stub, sizeof request_stub);
nl_msg_put_genlmsghdr(&request, 0, OVS_WIN_NL_CTRL_FAMILY_ID, 0,
OVS_CTRL_CMD_MC_SUBSCRIBE_REQ,
OVS_WIN_CONTROL_VERSION);
ovs_header = ofpbuf_put_uninit(&request, sizeof *ovs_header);
ovs_header->dp_ifindex = 0;
nl_msg_put_u32(&request, OVS_NL_ATTR_MCAST_GRP, multicast_group);
nl_msg_put_u8(&request, OVS_NL_ATTR_MCAST_JOIN, join ? 1 : 0);
error = nl_sock_send(sock, &request, true);
ofpbuf_uninit(&request);
return error;
}
#endif
/* Tries to add 'sock' as a listener for 'multicast_group'. Returns 0 if
* successful, otherwise a positive errno value.
*
* A socket that is subscribed to a multicast group that receives asynchronous
* notifications must not be used for Netlink transactions or dumps, because
* transactions and dumps can cause notifications to be lost.
*
* Multicast group numbers are always positive.
*
* It is not an error to attempt to join a multicast group to which a socket
* already belongs. */
int
nl_sock_join_mcgroup(struct nl_sock *sock, unsigned int multicast_group)
{
#ifdef _WIN32
/* Set the socket type as a "multicast" socket */
sock->read_ioctl = OVS_IOCTL_READ_EVENT;
int error = nl_sock_mcgroup(sock, multicast_group, true);
if (error) {
sock->read_ioctl = OVS_IOCTL_READ;
VLOG_WARN("could not join multicast group %u (%s)",
multicast_group, ovs_strerror(error));
return error;
}
#else
if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP,
&multicast_group, sizeof multicast_group) < 0) {
VLOG_WARN("could not join multicast group %u (%s)",
multicast_group, ovs_strerror(errno));
return errno;
}
#endif
return 0;
}
#ifdef _WIN32
int
nl_sock_subscribe_packet__(struct nl_sock *sock, bool subscribe)
{
struct ofpbuf request;
uint64_t request_stub[128];
struct ovs_header *ovs_header;
struct nlmsghdr *nlmsg;
int error;
ofpbuf_use_stub(&request, request_stub, sizeof request_stub);
nl_msg_put_genlmsghdr(&request, 0, OVS_WIN_NL_CTRL_FAMILY_ID, 0,
OVS_CTRL_CMD_PACKET_SUBSCRIBE_REQ,
OVS_WIN_CONTROL_VERSION);
ovs_header = ofpbuf_put_uninit(&request, sizeof *ovs_header);
ovs_header->dp_ifindex = 0;
nl_msg_put_u8(&request, OVS_NL_ATTR_PACKET_SUBSCRIBE, subscribe ? 1 : 0);
nl_msg_put_u32(&request, OVS_NL_ATTR_PACKET_PID, sock->pid);
error = nl_sock_send(sock, &request, true);
ofpbuf_uninit(&request);
return error;
}
int
nl_sock_subscribe_packets(struct nl_sock *sock)
{
int error;
if (sock->read_ioctl != OVS_IOCTL_READ) {
return EINVAL;
}
error = nl_sock_subscribe_packet__(sock, true);
if (error) {
VLOG_WARN("could not subscribe packets (%s)",
ovs_strerror(error));
return error;
}
sock->read_ioctl = OVS_IOCTL_READ_PACKET;
return 0;
}
int
nl_sock_unsubscribe_packets(struct nl_sock *sock)
{
ovs_assert(sock->read_ioctl == OVS_IOCTL_READ_PACKET);
int error = nl_sock_subscribe_packet__(sock, false);
if (error) {
VLOG_WARN("could not unsubscribe to packets (%s)",
ovs_strerror(error));
return error;
}
sock->read_ioctl = OVS_IOCTL_READ;
return 0;
}
#endif
/* Tries to make 'sock' stop listening to 'multicast_group'. Returns 0 if
* successful, otherwise a positive errno value.
*
* Multicast group numbers are always positive.
*
* It is not an error to attempt to leave a multicast group to which a socket
* does not belong.
*
* On success, reading from 'sock' will still return any messages that were
* received on 'multicast_group' before the group was left. */
int
nl_sock_leave_mcgroup(struct nl_sock *sock, unsigned int multicast_group)
{
#ifdef _WIN32
int error = nl_sock_mcgroup(sock, multicast_group, false);
if (error) {
VLOG_WARN("could not leave multicast group %u (%s)",
multicast_group, ovs_strerror(error));
return error;
}
sock->read_ioctl = OVS_IOCTL_READ;
#else
if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP,
&multicast_group, sizeof multicast_group) < 0) {
VLOG_WARN("could not leave multicast group %u (%s)",
multicast_group, ovs_strerror(errno));
return errno;
}
#endif
return 0;
}
static int
nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg,
uint32_t nlmsg_seq, bool wait)
{
struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg);
int error;
nlmsg->nlmsg_len = msg->size;
nlmsg->nlmsg_seq = nlmsg_seq;
nlmsg->nlmsg_pid = sock->pid;
do {
int retval;
#ifdef _WIN32
DWORD bytes;
if (!DeviceIoControl(sock->handle, OVS_IOCTL_WRITE,
msg->data, msg->size, NULL, 0,
&bytes, NULL)) {
lost_communication(GetLastError());
retval = -1;
/* XXX: Map to a more appropriate error based on GetLastError(). */
errno = EINVAL;
VLOG_DBG_RL(&rl, "fatal driver failure in write: %s",
ovs_lasterror_to_string());
} else {
retval = msg->size;
}
#else
retval = send(sock->fd, msg->data, msg->size,
wait ? 0 : MSG_DONTWAIT);
#endif
error = retval < 0 ? errno : 0;
} while (error == EINTR);
log_nlmsg(__func__, error, msg->data, msg->size, sock->protocol);
if (!error) {
COVERAGE_INC(netlink_sent);
}
return error;
}
/* Tries to send 'msg', which must contain a Netlink message, to the kernel on
* 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
* will be set to 'sock''s pid, and nlmsg_seq will be initialized to a fresh
* sequence number, before the message is sent.
*
* Returns 0 if successful, otherwise a positive errno value. If
* 'wait' is true, then the send will wait until buffer space is ready;
* otherwise, returns EAGAIN if the 'sock' send buffer is full. */
int
nl_sock_send(struct nl_sock *sock, const struct ofpbuf *msg, bool wait)
{
return nl_sock_send_seq(sock, msg, nl_sock_allocate_seq(sock, 1), wait);
}
/* Tries to send 'msg', which must contain a Netlink message, to the kernel on
* 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, nlmsg_pid
* will be set to 'sock''s pid, and nlmsg_seq will be initialized to
* 'nlmsg_seq', before the message is sent.
*
* Returns 0 if successful, otherwise a positive errno value. If
* 'wait' is true, then the send will wait until buffer space is ready;
* otherwise, returns EAGAIN if the 'sock' send buffer is full.
*
* This function is suitable for sending a reply to a request that was received
* with sequence number 'nlmsg_seq'. Otherwise, use nl_sock_send() instead. */
int
nl_sock_send_seq(struct nl_sock *sock, const struct ofpbuf *msg,
uint32_t nlmsg_seq, bool wait)
{
return nl_sock_send__(sock, msg, nlmsg_seq, wait);
}
static int
nl_sock_recv__(struct nl_sock *sock, struct ofpbuf *buf, bool wait)
{
/* We can't accurately predict the size of the data to be received. The
* caller is supposed to have allocated enough space in 'buf' to handle the
* "typical" case. To handle exceptions, we make available enough space in
* 'tail' to allow Netlink messages to be up to 64 kB long (a reasonable
* figure since that's the maximum length of a Netlink attribute). */
struct nlmsghdr *nlmsghdr;
uint8_t tail[65536];
struct iovec iov[2];
struct msghdr msg;
ssize_t retval;
int error;
ovs_assert(buf->allocated >= sizeof *nlmsghdr);
ofpbuf_clear(buf);
iov[0].iov_base = buf->base;
iov[0].iov_len = buf->allocated;
iov[1].iov_base = tail;
iov[1].iov_len = sizeof tail;
memset(&msg, 0, sizeof msg);
msg.msg_iov = iov;
msg.msg_iovlen = 2;
/* Receive a Netlink message from the kernel.
*
* This works around a kernel bug in which the kernel returns an error code
* as if it were the number of bytes read. It doesn't actually modify
* anything in the receive buffer in that case, so we can initialize the
* Netlink header with an impossible message length and then, upon success,
* check whether it changed. */
nlmsghdr = buf->base;
do {
nlmsghdr->nlmsg_len = UINT32_MAX;
#ifdef _WIN32
DWORD bytes;
if (!DeviceIoControl(sock->handle, sock->read_ioctl,
NULL, 0, tail, sizeof tail, &bytes, NULL)) {
lost_communication(GetLastError());
VLOG_DBG_RL(&rl, "fatal driver failure in transact: %s",
ovs_lasterror_to_string());
retval = -1;
/* XXX: Map to a more appropriate error. */
errno = EINVAL;
} else {
retval = bytes;
if (retval == 0) {
retval = -1;
errno = EAGAIN;
} else {
if (retval >= buf->allocated) {
ofpbuf_reinit(buf, retval);
nlmsghdr = buf->base;
nlmsghdr->nlmsg_len = UINT32_MAX;
}
memcpy(buf->data, tail, retval);
buf->size = retval;
}
}
#else
retval = recvmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
#endif
error = (retval < 0 ? errno
: retval == 0 ? ECONNRESET /* not possible? */
: nlmsghdr->nlmsg_len != UINT32_MAX ? 0
: retval);
} while (error == EINTR);
if (error) {
if (error == ENOBUFS) {
/* Socket receive buffer overflow dropped one or more messages that
* the kernel tried to send to us. */
COVERAGE_INC(netlink_overflow);
}
return error;
}
if (msg.msg_flags & MSG_TRUNC) {
VLOG_ERR_RL(&rl, "truncated message (longer than %"PRIuSIZE" bytes)",
sizeof tail);
return E2BIG;
}
if (retval < sizeof *nlmsghdr
|| nlmsghdr->nlmsg_len < sizeof *nlmsghdr
|| nlmsghdr->nlmsg_len > retval) {
VLOG_ERR_RL(&rl, "received invalid nlmsg (%"PRIuSIZE" bytes < %"PRIuSIZE")",
retval, sizeof *nlmsghdr);
return EPROTO;
}
#ifndef _WIN32
buf->size = MIN(retval, buf->allocated);
if (retval > buf->allocated) {
COVERAGE_INC(netlink_recv_jumbo);
ofpbuf_put(buf, tail, retval - buf->allocated);
}
#endif
log_nlmsg(__func__, 0, buf->data, buf->size, sock->protocol);
COVERAGE_INC(netlink_received);
return 0;
}
/* Tries to receive a Netlink message from the kernel on 'sock' into 'buf'. If
* 'wait' is true, waits for a message to be ready. Otherwise, fails with
* EAGAIN if the 'sock' receive buffer is empty.
*
* The caller must have initialized 'buf' with an allocation of at least
* NLMSG_HDRLEN bytes. For best performance, the caller should allocate enough
* space for a "typical" message.
*
* On success, returns 0 and replaces 'buf''s previous content by the received
* message. This function expands 'buf''s allocated memory, as necessary, to
* hold the actual size of the received message.
*
* On failure, returns a positive errno value and clears 'buf' to zero length.
* 'buf' retains its previous memory allocation.
*
* Regardless of success or failure, this function resets 'buf''s headroom to
* 0. */
int
nl_sock_recv(struct nl_sock *sock, struct ofpbuf *buf, bool wait)
{
return nl_sock_recv__(sock, buf, wait);
}
static void
nl_sock_record_errors__(struct nl_transaction **transactions, size_t n,
int error)
{
size_t i;
for (i = 0; i < n; i++) {
struct nl_transaction *txn = transactions[i];
txn->error = error;
if (txn->reply) {
ofpbuf_clear(txn->reply);
}
}
}
static int
nl_sock_transact_multiple__(struct nl_sock *sock,
struct nl_transaction **transactions, size_t n,
size_t *done)
{
uint64_t tmp_reply_stub[1024 / 8];
struct nl_transaction tmp_txn;
struct ofpbuf tmp_reply;
uint32_t base_seq;
struct iovec iovs[MAX_IOVS];
struct msghdr msg;
int error;
int i;
base_seq = nl_sock_allocate_seq(sock, n);
*done = 0;
for (i = 0; i < n; i++) {
struct nl_transaction *txn = transactions[i];
struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(txn->request);
nlmsg->nlmsg_len = txn->request->size;
nlmsg->nlmsg_seq = base_seq + i;
nlmsg->nlmsg_pid = sock->pid;
iovs[i].iov_base = txn->request->data;
iovs[i].iov_len = txn->request->size;
}
#ifndef _WIN32
memset(&msg, 0, sizeof msg);
msg.msg_iov = iovs;
msg.msg_iovlen = n;
do {
error = sendmsg(sock->fd, &msg, 0) < 0 ? errno : 0;
} while (error == EINTR);
for (i = 0; i < n; i++) {
struct nl_transaction *txn = transactions[i];
log_nlmsg(__func__, error, txn->request->data,
txn->request->size, sock->protocol);
}
if (!error) {
COVERAGE_ADD(netlink_sent, n);
}
if (error) {
return error;
}
ofpbuf_use_stub(&tmp_reply, tmp_reply_stub, sizeof tmp_reply_stub);
tmp_txn.request = NULL;
tmp_txn.reply = &tmp_reply;
tmp_txn.error = 0;
while (n > 0) {
struct nl_transaction *buf_txn, *txn;
uint32_t seq;
/* Find a transaction whose buffer we can use for receiving a reply.
* If no such transaction is left, use tmp_txn. */
buf_txn = &tmp_txn;
for (i = 0; i < n; i++) {
if (transactions[i]->reply) {
buf_txn = transactions[i];
break;
}
}
/* Receive a reply. */
error = nl_sock_recv__(sock, buf_txn->reply, false);
if (error) {
if (error == EAGAIN) {
nl_sock_record_errors__(transactions, n, 0);
*done += n;
error = 0;
}
break;
}
/* Match the reply up with a transaction. */
seq = nl_msg_nlmsghdr(buf_txn->reply)->nlmsg_seq;
if (seq < base_seq || seq >= base_seq + n) {
VLOG_DBG_RL(&rl, "ignoring unexpected seq %#"PRIx32, seq);
continue;
}
i = seq - base_seq;
txn = transactions[i];
/* Fill in the results for 'txn'. */
if (nl_msg_nlmsgerr(buf_txn->reply, &txn->error)) {
if (txn->reply) {
ofpbuf_clear(txn->reply);
}
if (txn->error) {
VLOG_DBG_RL(&rl, "received NAK error=%d (%s)",
error, ovs_strerror(txn->error));
}
} else {
txn->error = 0;
if (txn->reply && txn != buf_txn) {
/* Swap buffers. */
struct ofpbuf *reply = buf_txn->reply;
buf_txn->reply = txn->reply;
txn->reply = reply;
}
}
/* Fill in the results for transactions before 'txn'. (We have to do
* this after the results for 'txn' itself because of the buffer swap
* above.) */
nl_sock_record_errors__(transactions, i, 0);
/* Advance. */
*done += i + 1;
transactions += i + 1;
n -= i + 1;
base_seq += i + 1;
}
ofpbuf_uninit(&tmp_reply);
#else
error = 0;
uint8_t reply_buf[65536];
for (i = 0; i < n; i++) {
DWORD reply_len;
bool ret;
struct nl_transaction *txn = transactions[i];
struct nlmsghdr *request_nlmsg, *reply_nlmsg;
ret = DeviceIoControl(sock->handle, OVS_IOCTL_TRANSACT,
txn->request->data,
txn->request->size,
reply_buf, sizeof reply_buf,
&reply_len, NULL);
if (ret && reply_len == 0) {
/*
* The current transaction did not produce any data to read and that
* is not an error as such. Continue with the remainder of the
* transactions.
*/
txn->error = 0;
if (txn->reply) {
ofpbuf_clear(txn->reply);
}
} else if (!ret) {
/* XXX: Map to a more appropriate error. */
lost_communication(GetLastError());
error = EINVAL;
VLOG_DBG_RL(&rl, "fatal driver failure: %s",
ovs_lasterror_to_string());
break;
}
if (reply_len != 0) {
request_nlmsg = nl_msg_nlmsghdr(txn->request);
if (reply_len < sizeof *reply_nlmsg) {
nl_sock_record_errors__(transactions, n, 0);
VLOG_DBG_RL(&rl, "insufficient length of reply %#"PRIu32
" for seq: %#"PRIx32, reply_len, request_nlmsg->nlmsg_seq);
break;
}
/* Validate the sequence number in the reply. */
reply_nlmsg = (struct nlmsghdr *)reply_buf;
if (request_nlmsg->nlmsg_seq != reply_nlmsg->nlmsg_seq) {
ovs_assert(request_nlmsg->nlmsg_seq == reply_nlmsg->nlmsg_seq);
VLOG_DBG_RL(&rl, "mismatched seq request %#"PRIx32
", reply %#"PRIx32, request_nlmsg->nlmsg_seq,
reply_nlmsg->nlmsg_seq);
break;
}
/* Handle errors embedded within the netlink message. */
ofpbuf_use_stub(&tmp_reply, reply_buf, sizeof reply_buf);
tmp_reply.size = sizeof reply_buf;
if (nl_msg_nlmsgerr(&tmp_reply, &txn->error)) {
if (txn->reply) {
ofpbuf_clear(txn->reply);
}
if (txn->error) {
VLOG_DBG_RL(&rl, "received NAK error=%d (%s)",
error, ovs_strerror(txn->error));
}
} else {
txn->error = 0;
if (txn->reply) {
/* Copy the reply to the buffer specified by the caller. */
if (reply_len > txn->reply->allocated) {
ofpbuf_reinit(txn->reply, reply_len);
}
memcpy(txn->reply->data, reply_buf, reply_len);
txn->reply->size = reply_len;
}
}
ofpbuf_uninit(&tmp_reply);
}
/* Count the number of successful transactions. */
(*done)++;
}
if (!error) {
COVERAGE_ADD(netlink_sent, n);
}
#endif
return error;
}
static void
nl_sock_transact_multiple(struct nl_sock *sock,
struct nl_transaction **transactions, size_t n)
{
int max_batch_count;
int error;
if (!n) {
return;
}
/* In theory, every request could have a 64 kB reply. But the default and
* maximum socket rcvbuf size with typical Dom0 memory sizes both tend to
* be a bit below 128 kB, so that would only allow a single message in a
* "batch". So we assume that replies average (at most) 4 kB, which allows
* a good deal of batching.
*
* In practice, most of the requests that we batch either have no reply at
* all or a brief reply. */
max_batch_count = MAX(sock->rcvbuf / 4096, 1);
max_batch_count = MIN(max_batch_count, max_iovs);
while (n > 0) {
size_t count, bytes;
size_t done;
/* Batch up to 'max_batch_count' transactions. But cap it at about a
* page of requests total because big skbuffs are expensive to
* allocate in the kernel. */
#if defined(PAGESIZE)
enum { MAX_BATCH_BYTES = MAX(1, PAGESIZE - 512) };
#else
enum { MAX_BATCH_BYTES = 4096 - 512 };
#endif
bytes = transactions[0]->request->size;
for (count = 1; count < n && count < max_batch_count; count++) {
if (bytes + transactions[count]->request->size > MAX_BATCH_BYTES) {
break;
}
bytes += transactions[count]->request->size;
}
error = nl_sock_transact_multiple__(sock, transactions, count, &done);
transactions += done;
n -= done;
if (error == ENOBUFS) {
VLOG_DBG_RL(&rl, "receive buffer overflow, resending request");
} else if (error) {
VLOG_ERR_RL(&rl, "transaction error (%s)", ovs_strerror(error));
nl_sock_record_errors__(transactions, n, error);
if (error != EAGAIN) {
/* A fatal error has occurred. Abort the rest of
* transactions. */
break;
}
}
}
}
static int
nl_sock_transact(struct nl_sock *sock, const struct ofpbuf *request,
struct ofpbuf **replyp)
{
struct nl_transaction *transactionp;
struct nl_transaction transaction;
transaction.request = CONST_CAST(struct ofpbuf *, request);
transaction.reply = replyp ? ofpbuf_new(1024) : NULL;
transactionp = &transaction;
nl_sock_transact_multiple(sock, &transactionp, 1);
if (replyp) {
if (transaction.error) {
ofpbuf_delete(transaction.reply);
*replyp = NULL;
} else {
*replyp = transaction.reply;
}
}
return transaction.error;
}
/* Drain all the messages currently in 'sock''s receive queue. */
int
nl_sock_drain(struct nl_sock *sock)
{
#ifdef _WIN32
return 0;
#else
return drain_rcvbuf(sock->fd);
#endif
}
/* Starts a Netlink "dump" operation, by sending 'request' to the kernel on a
* Netlink socket created with the given 'protocol', and initializes 'dump' to
* reflect the state of the operation.
*
* 'request' must contain a Netlink message. Before sending the message,
* nlmsg_len will be finalized to match request->size, and nlmsg_pid will be
* set to the Netlink socket's pid. NLM_F_DUMP and NLM_F_ACK will be set in
* nlmsg_flags.
*
* The design of this Netlink socket library ensures that the dump is reliable.
*
* This function provides no status indication. nl_dump_done() provides an
* error status for the entire dump operation.
*
* The caller must eventually destroy 'request'.
*/
void
nl_dump_start(struct nl_dump *dump, int protocol, const struct ofpbuf *request)
{
nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK;
ovs_mutex_init(&dump->mutex);
ovs_mutex_lock(&dump->mutex);
dump->status = nl_pool_alloc(protocol, &dump->sock);
if (!dump->status) {
dump->status = nl_sock_send__(dump->sock, request,
nl_sock_allocate_seq(dump->sock, 1),
true);
}
dump->nl_seq = nl_msg_nlmsghdr(request)->nlmsg_seq;
ovs_mutex_unlock(&dump->mutex);
}
static int
nl_dump_refill(struct nl_dump *dump, struct ofpbuf *buffer)
OVS_REQUIRES(dump->mutex)
{
struct nlmsghdr *nlmsghdr;
int error;
while (!buffer->size) {
error = nl_sock_recv__(dump->sock, buffer, false);
if (error) {
/* The kernel never blocks providing the results of a dump, so
* error == EAGAIN means that we've read the whole thing, and
* therefore transform it into EOF. (The kernel always provides
* NLMSG_DONE as a sentinel. Some other thread must have received
* that already but not yet signaled it in 'status'.)
*
* Any other error is just an error. */
return error == EAGAIN ? EOF : error;
}
nlmsghdr = nl_msg_nlmsghdr(buffer);
if (dump->nl_seq != nlmsghdr->nlmsg_seq) {
VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32,
nlmsghdr->nlmsg_seq, dump->nl_seq);
ofpbuf_clear(buffer);
}
}
if (nl_msg_nlmsgerr(buffer, &error) && error) {
VLOG_INFO_RL(&rl, "netlink dump request error (%s)",
ovs_strerror(error));
ofpbuf_clear(buffer);
return error;
}
return 0;
}
static int
nl_dump_next__(struct ofpbuf *reply, struct ofpbuf *buffer)
{
struct nlmsghdr *nlmsghdr = nl_msg_next(buffer, reply);
if (!nlmsghdr) {
VLOG_WARN_RL(&rl, "netlink dump contains message fragment");
return EPROTO;
} else if (nlmsghdr->nlmsg_type == NLMSG_DONE) {
return EOF;
} else {
return 0;
}
}
/* Attempts to retrieve another reply from 'dump' into 'buffer'. 'dump' must
* have been initialized with nl_dump_start(), and 'buffer' must have been
* initialized. 'buffer' should be at least NL_DUMP_BUFSIZE bytes long.
*
* If successful, returns true and points 'reply->data' and
* 'reply->size' to the message that was retrieved. The caller must not
* modify 'reply' (because it points within 'buffer', which will be used by
* future calls to this function).
*
* On failure, returns false and sets 'reply->data' to NULL and
* '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().
*
* Multiple threads may call this function, passing the same nl_dump, however
* each must provide independent buffers. This function may cache multiple
* replies in the buffer, and these will be processed before more replies are
* fetched. When this function returns false, other threads may continue to
* process replies in their buffers, but they will not fetch more replies.
*/
bool
nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply, struct ofpbuf *buffer)
{
int retval = 0;
/* If the buffer is empty, refill it.
*
* If the buffer is not empty, we don't check the dump's status.
* Otherwise, we could end up skipping some of the dump results if thread A
* hits EOF while thread B is in the midst of processing a batch. */
if (!buffer->size) {
ovs_mutex_lock(&dump->mutex);
if (!dump->status) {
/* Take the mutex here to avoid an in-kernel race. If two threads
* try to read from a Netlink dump socket at once, then the socket
* error can be set to EINVAL, which will be encountered on the
* next recv on that socket, which could be anywhere due to the way
* that we pool Netlink sockets. Serializing the recv calls avoids
* the issue. */
dump->status = nl_dump_refill(dump, buffer);
}
retval = dump->status;
ovs_mutex_unlock(&dump->mutex);
}
/* Fetch the next message from the buffer. */
if (!retval) {
retval = nl_dump_next__(reply, buffer);
if (retval) {
/* Record 'retval' as the dump status, but don't overwrite an error
* with EOF. */
ovs_mutex_lock(&dump->mutex);
if (dump->status <= 0) {
dump->status = retval;
}
ovs_mutex_unlock(&dump->mutex);
}
}
if (retval) {
reply->data = NULL;
reply->size = 0;
}
return !retval;
}
/* Completes Netlink dump operation 'dump', which must have been initialized
* with nl_dump_start(). Returns 0 if the dump operation was error-free,
* otherwise a positive errno value describing the problem. */
int
nl_dump_done(struct nl_dump *dump)
{
int status;
ovs_mutex_lock(&dump->mutex);
status = dump->status;
ovs_mutex_unlock(&dump->mutex);
/* Drain any remaining messages that the client didn't read. Otherwise the
* kernel will continue to queue them up and waste buffer space.
*
* XXX We could just destroy and discard the socket in this case. */
if (!status) {
uint64_t tmp_reply_stub[NL_DUMP_BUFSIZE / 8];
struct ofpbuf reply, buf;
ofpbuf_use_stub(&buf, tmp_reply_stub, sizeof tmp_reply_stub);
while (nl_dump_next(dump, &reply, &buf)) {
/* Nothing to do. */
}
ofpbuf_uninit(&buf);
ovs_mutex_lock(&dump->mutex);
status = dump->status;
ovs_mutex_unlock(&dump->mutex);
ovs_assert(status);
}
nl_pool_release(dump->sock);
ovs_mutex_destroy(&dump->mutex);
return status == EOF ? 0 : status;
}
#ifdef _WIN32
/* Pend an I/O request in the driver. The driver completes the I/O whenever
* an event or a packet is ready to be read. Once the I/O is completed
* the overlapped structure event associated with the pending I/O will be set
*/
static int
pend_io_request(struct nl_sock *sock)
{
struct ofpbuf request;
uint64_t request_stub[128];
struct ovs_header *ovs_header;
struct nlmsghdr *nlmsg;
uint32_t seq;
int retval = 0;
int error;
DWORD bytes;
OVERLAPPED *overlapped = CONST_CAST(OVERLAPPED *, &sock->overlapped);
uint16_t cmd = OVS_CTRL_CMD_WIN_PEND_PACKET_REQ;
ovs_assert(sock->read_ioctl == OVS_IOCTL_READ_PACKET ||
sock->read_ioctl == OVS_IOCTL_READ_EVENT);
if (sock->read_ioctl == OVS_IOCTL_READ_EVENT) {
cmd = OVS_CTRL_CMD_WIN_PEND_REQ;
}
int ovs_msg_size = sizeof (struct nlmsghdr) + sizeof (struct genlmsghdr) +
sizeof (struct ovs_header);
ofpbuf_use_stub(&request, request_stub, sizeof request_stub);
seq = nl_sock_allocate_seq(sock, 1);
nl_msg_put_genlmsghdr(&request, 0, OVS_WIN_NL_CTRL_FAMILY_ID, 0,
cmd, OVS_WIN_CONTROL_VERSION);
nlmsg = nl_msg_nlmsghdr(&request);
nlmsg->nlmsg_seq = seq;
nlmsg->nlmsg_pid = sock->pid;
ovs_header = ofpbuf_put_uninit(&request, sizeof *ovs_header);
ovs_header->dp_ifindex = 0;
nlmsg->nlmsg_len = request.size;
if (!DeviceIoControl(sock->handle, OVS_IOCTL_WRITE,
request.data, request.size,
NULL, 0, &bytes, overlapped)) {
error = GetLastError();
/* Check if the I/O got pended */
if (error != ERROR_IO_INCOMPLETE && error != ERROR_IO_PENDING) {
lost_communication(error);
VLOG_ERR("nl_sock_wait failed - %s\n", ovs_format_message(error));
retval = EINVAL;
}
} else {
retval = EAGAIN;
}
done:
ofpbuf_uninit(&request);
return retval;
}
#endif /* _WIN32 */
/* 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'.
* On Windows, 'sock' is not treated as const, and may be modified. */
void
nl_sock_wait(const struct nl_sock *sock, short int events)
{
#ifdef _WIN32
if (sock->overlapped.Internal != STATUS_PENDING) {
int ret = pend_io_request(CONST_CAST(struct nl_sock *, sock));
if (ret == 0) {
poll_wevent_wait(sock->overlapped.hEvent);
} else {
poll_immediate_wake();
}
} else {
poll_wevent_wait(sock->overlapped.hEvent);
}
#else
poll_fd_wait(sock->fd, events);
#endif
}
#ifndef _WIN32
/* Returns the underlying fd for 'sock', for use in "poll()"-like operations
* that can't use nl_sock_wait().
*
* It's a little tricky to use the returned fd correctly, because nl_sock does
* "copy on write" to allow a single nl_sock to be used for notifications,
* transactions, and dumps. If 'sock' is used only for notifications and
* transactions (and never for dump) then the usage is safe. */
int
nl_sock_fd(const struct nl_sock *sock)
{
return sock->fd;
}
#endif
/* Returns the PID associated with this socket. */
uint32_t
nl_sock_pid(const struct nl_sock *sock)
{
return sock->pid;
}
/* Miscellaneous. */
struct genl_family {
struct hmap_node hmap_node;
uint16_t id;
char *name;
};
static struct hmap genl_families = HMAP_INITIALIZER(&genl_families);
static const struct nl_policy family_policy[CTRL_ATTR_MAX + 1] = {
[CTRL_ATTR_FAMILY_ID] = {.type = NL_A_U16},
[CTRL_ATTR_MCAST_GROUPS] = {.type = NL_A_NESTED, .optional = true},
};
static struct genl_family *
find_genl_family_by_id(uint16_t id)
{
struct genl_family *family;
HMAP_FOR_EACH_IN_BUCKET (family, hmap_node, hash_int(id, 0),
&genl_families) {
if (family->id == id) {
return family;
}
}
return NULL;
}
static void
define_genl_family(uint16_t id, const char *name)
{
struct genl_family *family = find_genl_family_by_id(id);
if (family) {
if (!strcmp(family->name, name)) {
return;
}
free(family->name);
} else {
family = xmalloc(sizeof *family);
family->id = id;
hmap_insert(&genl_families, &family->hmap_node, hash_int(id, 0));
}
family->name = xstrdup(name);
}
static const char *
genl_family_to_name(uint16_t id)
{
if (id == GENL_ID_CTRL) {
return "control";
} else {
struct genl_family *family = find_genl_family_by_id(id);
return family ? family->name : "unknown";
}
}
#ifndef _WIN32
static int
do_lookup_genl_family(const char *name, struct nlattr **attrs,
struct ofpbuf **replyp)
{
struct nl_sock *sock;
struct ofpbuf request, *reply;
int error;
*replyp = NULL;
error = nl_sock_create(NETLINK_GENERIC, &sock);
if (error) {
return error;
}
ofpbuf_init(&request, 0);
nl_msg_put_genlmsghdr(&request, 0, GENL_ID_CTRL, NLM_F_REQUEST,
CTRL_CMD_GETFAMILY, 1);
nl_msg_put_string(&request, CTRL_ATTR_FAMILY_NAME, name);
error = nl_sock_transact(sock, &request, &reply);
ofpbuf_uninit(&request);
if (error) {
nl_sock_destroy(sock);
return error;
}
if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN,
family_policy, attrs, ARRAY_SIZE(family_policy))
|| nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]) == 0) {
nl_sock_destroy(sock);
ofpbuf_delete(reply);
return EPROTO;
}
nl_sock_destroy(sock);
*replyp = reply;
return 0;
}
#else
static int
do_lookup_genl_family(const char *name, struct nlattr **attrs,
struct ofpbuf **replyp)
{
struct nlmsghdr *nlmsg;
struct ofpbuf *reply;
int error;
uint16_t family_id;
const char *family_name;
uint32_t family_version;
uint32_t family_attrmax;
uint32_t mcgrp_id = OVS_WIN_NL_INVALID_MCGRP_ID;
const char *mcgrp_name = NULL;
*replyp = NULL;
reply = ofpbuf_new(1024);
/* CTRL_ATTR_MCAST_GROUPS is supported only for VPORT family. */
if (!strcmp(name, OVS_WIN_CONTROL_FAMILY)) {
family_id = OVS_WIN_NL_CTRL_FAMILY_ID;
family_name = OVS_WIN_CONTROL_FAMILY;
family_version = OVS_WIN_CONTROL_VERSION;
family_attrmax = OVS_WIN_CONTROL_ATTR_MAX;
} else if (!strcmp(name, OVS_DATAPATH_FAMILY)) {
family_id = OVS_WIN_NL_DATAPATH_FAMILY_ID;
family_name = OVS_DATAPATH_FAMILY;
family_version = OVS_DATAPATH_VERSION;
family_attrmax = OVS_DP_ATTR_MAX;
} else if (!strcmp(name, OVS_PACKET_FAMILY)) {
family_id = OVS_WIN_NL_PACKET_FAMILY_ID;
family_name = OVS_PACKET_FAMILY;
family_version = OVS_PACKET_VERSION;
family_attrmax = OVS_PACKET_ATTR_MAX;
} else if (!strcmp(name, OVS_VPORT_FAMILY)) {
family_id = OVS_WIN_NL_VPORT_FAMILY_ID;
family_name = OVS_VPORT_FAMILY;
family_version = OVS_VPORT_VERSION;
family_attrmax = OVS_VPORT_ATTR_MAX;
mcgrp_id = OVS_WIN_NL_VPORT_MCGRP_ID;
mcgrp_name = OVS_VPORT_MCGROUP;
} else if (!strcmp(name, OVS_FLOW_FAMILY)) {
family_id = OVS_WIN_NL_FLOW_FAMILY_ID;
family_name = OVS_FLOW_FAMILY;
family_version = OVS_FLOW_VERSION;
family_attrmax = OVS_FLOW_ATTR_MAX;
} else if (!strcmp(name, OVS_WIN_NETDEV_FAMILY)) {
family_id = OVS_WIN_NL_NETDEV_FAMILY_ID;
family_name = OVS_WIN_NETDEV_FAMILY;
family_version = OVS_WIN_NETDEV_VERSION;
family_attrmax = OVS_WIN_NETDEV_ATTR_MAX;
} else {
ofpbuf_delete(reply);
return EINVAL;
}
nl_msg_put_genlmsghdr(reply, 0, GENL_ID_CTRL, 0,
CTRL_CMD_NEWFAMILY, family_version);
/* CTRL_ATTR_HDRSIZE and CTRL_ATTR_OPS are not populated, but the
* callers do not seem to need them. */
nl_msg_put_u16(reply, CTRL_ATTR_FAMILY_ID, family_id);
nl_msg_put_string(reply, CTRL_ATTR_FAMILY_NAME, family_name);
nl_msg_put_u32(reply, CTRL_ATTR_VERSION, family_version);
nl_msg_put_u32(reply, CTRL_ATTR_MAXATTR, family_attrmax);
if (mcgrp_id != OVS_WIN_NL_INVALID_MCGRP_ID) {
size_t mcgrp_ofs1 = nl_msg_start_nested(reply, CTRL_ATTR_MCAST_GROUPS);
size_t mcgrp_ofs2= nl_msg_start_nested(reply,
OVS_WIN_NL_VPORT_MCGRP_ID - OVS_WIN_NL_MCGRP_START_ID);
nl_msg_put_u32(reply, CTRL_ATTR_MCAST_GRP_ID, mcgrp_id);
ovs_assert(mcgrp_name != NULL);
nl_msg_put_string(reply, CTRL_ATTR_MCAST_GRP_NAME, mcgrp_name);
nl_msg_end_nested(reply, mcgrp_ofs2);
nl_msg_end_nested(reply, mcgrp_ofs1);
}
/* Set the total length of the netlink message. */
nlmsg = nl_msg_nlmsghdr(reply);
nlmsg->nlmsg_len = reply->size;
if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN,
family_policy, attrs, ARRAY_SIZE(family_policy))
|| nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]) == 0) {
ofpbuf_delete(reply);
return EPROTO;
}
*replyp = reply;
return 0;
}
#endif
/* Finds the multicast group called 'group_name' in genl family 'family_name'.
* When successful, writes its result to 'multicast_group' and returns 0.
* Otherwise, clears 'multicast_group' and returns a positive error code.
*/
int
nl_lookup_genl_mcgroup(const char *family_name, const char *group_name,
unsigned int *multicast_group)
{
struct nlattr *family_attrs[ARRAY_SIZE(family_policy)];
const struct nlattr *mc;
struct ofpbuf *reply;
unsigned int left;
int error;
*multicast_group = 0;
error = do_lookup_genl_family(family_name, family_attrs, &reply);
if (error) {
return error;
}
if (!family_attrs[CTRL_ATTR_MCAST_GROUPS]) {
error = EPROTO;
goto exit;
}
NL_NESTED_FOR_EACH (mc, left, family_attrs[CTRL_ATTR_MCAST_GROUPS]) {
static const struct nl_policy mc_policy[] = {
[CTRL_ATTR_MCAST_GRP_ID] = {.type = NL_A_U32},
[CTRL_ATTR_MCAST_GRP_NAME] = {.type = NL_A_STRING},
};
struct nlattr *mc_attrs[ARRAY_SIZE(mc_policy)];
const char *mc_name;
if (!nl_parse_nested(mc, mc_policy, mc_attrs, ARRAY_SIZE(mc_policy))) {
error = EPROTO;
goto exit;
}
mc_name = nl_attr_get_string(mc_attrs[CTRL_ATTR_MCAST_GRP_NAME]);
if (!strcmp(group_name, mc_name)) {
*multicast_group =
nl_attr_get_u32(mc_attrs[CTRL_ATTR_MCAST_GRP_ID]);
error = 0;
goto exit;
}
}
error = EPROTO;
exit:
ofpbuf_delete(reply);
return error;
}
/* If '*number' is 0, translates the given Generic Netlink family 'name' to a
* number and stores it in '*number'. If successful, returns 0 and the caller
* may use '*number' as the family number. On failure, returns a positive
* errno value and '*number' caches the errno value. */
int
nl_lookup_genl_family(const char *name, int *number)
{
if (*number == 0) {
struct nlattr *attrs[ARRAY_SIZE(family_policy)];
struct ofpbuf *reply;
int error;
error = do_lookup_genl_family(name, attrs, &reply);
if (!error) {
*number = nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]);
define_genl_family(*number, name);
} else {
*number = -error;
}
ofpbuf_delete(reply);
ovs_assert(*number != 0);
}
return *number > 0 ? 0 : -*number;
}
struct nl_pool {
struct nl_sock *socks[16];
int n;
};
static struct ovs_mutex pool_mutex = OVS_MUTEX_INITIALIZER;
static struct nl_pool pools[MAX_LINKS] OVS_GUARDED_BY(pool_mutex);
static int
nl_pool_alloc(int protocol, struct nl_sock **sockp)
{
struct nl_sock *sock = NULL;
struct nl_pool *pool;
ovs_assert(protocol >= 0 && protocol < ARRAY_SIZE(pools));
ovs_mutex_lock(&pool_mutex);
pool = &pools[protocol];
if (pool->n > 0) {
sock = pool->socks[--pool->n];
}
ovs_mutex_unlock(&pool_mutex);
if (sock) {
*sockp = sock;
return 0;
} else {
return nl_sock_create(protocol, sockp);
}
}
static void
nl_pool_release(struct nl_sock *sock)
{
if (sock) {
struct nl_pool *pool = &pools[sock->protocol];
ovs_mutex_lock(&pool_mutex);
if (pool->n < ARRAY_SIZE(pool->socks)) {
pool->socks[pool->n++] = sock;
sock = NULL;
}
ovs_mutex_unlock(&pool_mutex);
nl_sock_destroy(sock);
}
}
/* Sends 'request' to the kernel on a Netlink socket for the given 'protocol'
* (e.g. NETLINK_ROUTE or NETLINK_GENERIC) and waits for a response. If
* successful, returns 0. On failure, returns a positive errno value.
*
* If 'replyp' is nonnull, then on success '*replyp' is set to the kernel's
* reply, which the caller is responsible for freeing with ofpbuf_delete(), and
* on failure '*replyp' is set to NULL. If 'replyp' is null, then the kernel's
* reply, if any, is discarded.
*
* Before the message is sent, nlmsg_len in 'request' will be finalized to
* match msg->size, nlmsg_pid will be set to the pid of the socket used
* for sending the request, and nlmsg_seq will be initialized.
*
* 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_transact(int protocol, const struct ofpbuf *request,
struct ofpbuf **replyp)
{
struct nl_sock *sock;
int error;
error = nl_pool_alloc(protocol, &sock);
if (error) {
if (replyp) {
*replyp = NULL;
}
return error;
}
error = nl_sock_transact(sock, request, replyp);
nl_pool_release(sock);
return error;
}
/* Sends the 'request' member of the 'n' transactions in 'transactions' on a
* Netlink socket for the given 'protocol' (e.g. NETLINK_ROUTE or
* NETLINK_GENERIC), in order, and receives responses to all of them. Fills in
* the 'error' member of each transaction with 0 if it was successful,
* otherwise with a positive errno value. If 'reply' is nonnull, then it will
* be filled with the reply if the message receives a detailed reply. In other
* cases, i.e. where the request failed or had no reply beyond an indication of
* success, 'reply' will be cleared if it is nonnull.
*
* The caller is responsible for destroying each request and reply, and the
* transactions array itself.
*
* Before sending each message, this function will finalize nlmsg_len in each
* 'request' to match the ofpbuf's size, set nlmsg_pid to the pid of the socket
* used for the transaction, and initialize nlmsg_seq.
*
* Bare Netlink is an unreliable transport protocol. This function layers
* reliable delivery and reply semantics on top of bare Netlink. See
* nl_transact() for some caveats.
*/
void
nl_transact_multiple(int protocol,
struct nl_transaction **transactions, size_t n)
{
struct nl_sock *sock;
int error;
error = nl_pool_alloc(protocol, &sock);
if (!error) {
nl_sock_transact_multiple(sock, transactions, n);
nl_pool_release(sock);
} else {
nl_sock_record_errors__(transactions, n, error);
}
}
static uint32_t
nl_sock_allocate_seq(struct nl_sock *sock, unsigned int n)
{
uint32_t seq = sock->next_seq;
sock->next_seq += n;
/* Make it impossible for the next request for sequence numbers to wrap
* around to 0. Start over with 1 to avoid ever using a sequence number of
* 0, because the kernel uses sequence number 0 for notifications. */
if (sock->next_seq >= UINT32_MAX / 2) {
sock->next_seq = 1;
}
return seq;
}
static void
nlmsghdr_to_string(const struct nlmsghdr *h, int protocol, struct ds *ds)
{
struct nlmsg_flag {
unsigned int bits;
const char *name;
};
static const struct nlmsg_flag flags[] = {
{ NLM_F_REQUEST, "REQUEST" },
{ NLM_F_MULTI, "MULTI" },
{ NLM_F_ACK, "ACK" },
{ NLM_F_ECHO, "ECHO" },
{ NLM_F_DUMP, "DUMP" },
{ NLM_F_ROOT, "ROOT" },
{ NLM_F_MATCH, "MATCH" },
{ NLM_F_ATOMIC, "ATOMIC" },
};
const struct nlmsg_flag *flag;
uint16_t flags_left;
ds_put_format(ds, "nl(len:%"PRIu32", type=%"PRIu16,
h->nlmsg_len, h->nlmsg_type);
if (h->nlmsg_type == NLMSG_NOOP) {
ds_put_cstr(ds, "(no-op)");
} else if (h->nlmsg_type == NLMSG_ERROR) {
ds_put_cstr(ds, "(error)");
} else if (h->nlmsg_type == NLMSG_DONE) {
ds_put_cstr(ds, "(done)");
} else if (h->nlmsg_type == NLMSG_OVERRUN) {
ds_put_cstr(ds, "(overrun)");
} else if (h->nlmsg_type < NLMSG_MIN_TYPE) {
ds_put_cstr(ds, "(reserved)");
} else if (protocol == NETLINK_GENERIC) {
ds_put_format(ds, "(%s)", genl_family_to_name(h->nlmsg_type));
} else {
ds_put_cstr(ds, "(family-defined)");
}
ds_put_format(ds, ", flags=%"PRIx16, h->nlmsg_flags);
flags_left = h->nlmsg_flags;
for (flag = flags; flag < &flags[ARRAY_SIZE(flags)]; flag++) {
if ((flags_left & flag->bits) == flag->bits) {
ds_put_format(ds, "[%s]", flag->name);
flags_left &= ~flag->bits;
}
}
if (flags_left) {
ds_put_format(ds, "[OTHER:%"PRIx16"]", flags_left);
}
ds_put_format(ds, ", seq=%"PRIx32", pid=%"PRIu32,
h->nlmsg_seq, h->nlmsg_pid);
}
static char *
nlmsg_to_string(const struct ofpbuf *buffer, int protocol)
{
struct ds ds = DS_EMPTY_INITIALIZER;
const struct nlmsghdr *h = ofpbuf_at(buffer, 0, NLMSG_HDRLEN);
if (h) {
nlmsghdr_to_string(h, protocol, &ds);
if (h->nlmsg_type == NLMSG_ERROR) {
const struct nlmsgerr *e;
e = ofpbuf_at(buffer, NLMSG_HDRLEN,
NLMSG_ALIGN(sizeof(struct nlmsgerr)));
if (e) {
ds_put_format(&ds, " error(%d", e->error);
if (e->error < 0) {
ds_put_format(&ds, "(%s)", ovs_strerror(-e->error));
}
ds_put_cstr(&ds, ", in-reply-to(");
nlmsghdr_to_string(&e->msg, protocol, &ds);
ds_put_cstr(&ds, "))");
} else {
ds_put_cstr(&ds, " error(truncated)");
}
} else if (h->nlmsg_type == NLMSG_DONE) {
int *error = ofpbuf_at(buffer, NLMSG_HDRLEN, sizeof *error);
if (error) {
ds_put_format(&ds, " done(%d", *error);
if (*error < 0) {
ds_put_format(&ds, "(%s)", ovs_strerror(-*error));
}
ds_put_cstr(&ds, ")");
} else {
ds_put_cstr(&ds, " done(truncated)");
}
} else if (protocol == NETLINK_GENERIC) {
struct genlmsghdr *genl = nl_msg_genlmsghdr(buffer);
if (genl) {
ds_put_format(&ds, ",genl(cmd=%"PRIu8",version=%"PRIu8")",
genl->cmd, genl->version);
}
}
} else {
ds_put_cstr(&ds, "nl(truncated)");
}
return ds.string;
}
static void
log_nlmsg(const char *function, int error,
const void *message, size_t size, int protocol)
{
if (!VLOG_IS_DBG_ENABLED()) {
return;
}
struct ofpbuf buffer = ofpbuf_const_initializer(message, size);
char *nlmsg = nlmsg_to_string(&buffer, protocol);
VLOG_DBG_RL(&rl, "%s (%s): %s", function, ovs_strerror(error), nlmsg);
free(nlmsg);
}
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