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/*
* Copyright (c) 2009, 2010 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "rtnetlink.h"
#include <errno.h>
#include <sys/socket.h>
#include <linux/rtnetlink.h>
#include <net/if.h>
#include <poll.h>
#include "coverage.h"
#include "netlink.h"
#include "ofpbuf.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(rtnetlink)
/* rtnetlink socket. */
static struct nl_sock *notify_sock;
/* All registered notifiers. */
static struct list all_notifiers = LIST_INITIALIZER(&all_notifiers);
static void rtnetlink_report_change(const struct nlmsghdr *,
const struct ifinfomsg *,
struct nlattr *attrs[]);
static void rtnetlink_report_notify_error(void);
/* Registers 'cb' to be called with auxiliary data 'aux' with network device
* change notifications. The notifier is stored in 'notifier', which the
* caller must not modify or free.
*
* This is probably not the function that you want. You should probably be
* using xfif_port_poll() or netdev_monitor_create(), which unlike this
* function are not Linux-specific.
*
* Returns 0 if successful, otherwise a positive errno value. */
int
rtnetlink_notifier_register(struct rtnetlink_notifier *notifier,
rtnetlink_notify_func *cb, void *aux)
{
if (!notify_sock) {
int error = nl_sock_create(NETLINK_ROUTE, RTNLGRP_LINK, 0, 0,
¬ify_sock);
if (error) {
VLOG_WARN("could not create rtnetlink socket: %s",
strerror(error));
return error;
}
} else {
/* Catch up on notification work so that the new notifier won't
* receive any stale notifications. */
rtnetlink_notifier_run();
}
list_push_back(&all_notifiers, ¬ifier->node);
notifier->cb = cb;
notifier->aux = aux;
return 0;
}
/* Cancels notification on 'notifier', which must have previously been
* registered with rtnetlink_notifier_register(). */
void
rtnetlink_notifier_unregister(struct rtnetlink_notifier *notifier)
{
list_remove(¬ifier->node);
if (list_is_empty(&all_notifiers)) {
nl_sock_destroy(notify_sock);
notify_sock = NULL;
}
}
/* Calls all of the registered notifiers, passing along any as-yet-unreported
* netdev change events. */
void
rtnetlink_notifier_run(void)
{
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
if (!notify_sock) {
return;
}
for (;;) {
/* Policy for RTNLGRP_LINK messages.
*
* There are *many* more fields in these messages, but currently we
* only care about these fields. */
static const struct nl_policy rtnetlink_policy[] = {
[IFLA_IFNAME] = { .type = NL_A_STRING, .optional = false },
[IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
};
struct nlattr *attrs[ARRAY_SIZE(rtnetlink_policy)];
struct ofpbuf *buf;
int error;
error = nl_sock_recv(notify_sock, &buf, false);
if (!error) {
if (nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
rtnetlink_policy,
attrs, ARRAY_SIZE(rtnetlink_policy))) {
struct ifinfomsg *ifinfo;
ifinfo = (void *) ((char *) buf->data + NLMSG_HDRLEN);
rtnetlink_report_change(buf->data, ifinfo, attrs);
} else {
VLOG_WARN_RL(&rl, "received bad rtnl message");
rtnetlink_report_notify_error();
}
ofpbuf_delete(buf);
} else if (error == EAGAIN) {
return;
} else {
if (error == ENOBUFS) {
VLOG_WARN_RL(&rl, "rtnetlink receive buffer overflowed");
} else {
VLOG_WARN_RL(&rl, "error reading rtnetlink socket: %s",
strerror(error));
}
rtnetlink_report_notify_error();
}
}
}
/* Causes poll_block() to wake up when network device change notifications are
* ready. */
void
rtnetlink_notifier_wait(void)
{
if (notify_sock) {
nl_sock_wait(notify_sock, POLLIN);
}
}
static void
rtnetlink_report_change(const struct nlmsghdr *nlmsg,
const struct ifinfomsg *ifinfo,
struct nlattr *attrs[])
{
struct rtnetlink_notifier *notifier;
struct rtnetlink_change change;
COVERAGE_INC(rtnetlink_changed);
change.nlmsg_type = nlmsg->nlmsg_type;
change.ifi_index = ifinfo->ifi_index;
change.ifname = nl_attr_get_string(attrs[IFLA_IFNAME]);
change.master_ifindex = (attrs[IFLA_MASTER]
? nl_attr_get_u32(attrs[IFLA_MASTER]) : 0);
LIST_FOR_EACH (notifier, struct rtnetlink_notifier, node,
&all_notifiers) {
notifier->cb(&change, notifier->aux);
}
}
static void
rtnetlink_report_notify_error(void)
{
struct rtnetlink_notifier *notifier;
LIST_FOR_EACH (notifier, struct rtnetlink_notifier, node,
&all_notifiers) {
notifier->cb(NULL, notifier->aux);
}
}
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