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/*
* Copyright (c) 2011 Gaetano Catalli.
*
* 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 <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/route.h>
#include <poll.h>
#include "coverage.h"
#include "socket-util.h"
#include "poll-loop.h"
#include "vlog.h"
#include "rtbsd.h"
VLOG_DEFINE_THIS_MODULE(rtbsd);
COVERAGE_DEFINE(rtbsd_changed);
/* PF_ROUTE socket. */
static int notify_sock = -1;
/* All registered notifiers. */
static struct list all_notifiers = LIST_INITIALIZER(&all_notifiers);
static void rtbsd_report_change(const struct if_msghdr *);
static void rtbsd_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.
*
* Returns 0 if successful, otherwise a positive errno value. */
int
rtbsd_notifier_register(struct rtbsd_notifier *notifier,
rtbsd_notify_func *cb, void *aux)
{
if (notify_sock < 0) {
int error;
notify_sock = socket(PF_ROUTE, SOCK_RAW, 0);
if (notify_sock < 0) {
VLOG_WARN("could not create PF_ROUTE socket: %s",
strerror(errno));
return errno;
}
error = set_nonblocking(notify_sock);
if (error) {
VLOG_WARN("error set_nonblocking PF_ROUTE socket: %s",
strerror(error));
return error;
}
} else {
/* Catch up on notification work so that the new notifier won't
* receive any stale notifications. XXX*/
rtbsd_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 rtbsd_notifier_register(). */
void
rtbsd_notifier_unregister(struct rtbsd_notifier *notifier)
{
list_remove(¬ifier->node);
if (list_is_empty(&all_notifiers)) {
close(notify_sock);
notify_sock = -1;
}
}
/* Calls all of the registered notifiers, passing along any as-yet-unreported
* netdev change events. */
void
rtbsd_notifier_run(void)
{
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
struct if_msghdr msg;
if (notify_sock < 0) {
return;
}
for (;;) {
int retval;
msg.ifm_type = RTM_IFINFO;
msg.ifm_version = RTM_VERSION; //XXX check if necessary
/* read from PF_ROUTE socket */
retval = read(notify_sock, (char *)&msg, sizeof(msg));
if (retval >= 0) {
/* received packet from PF_ROUTE socket
* XXX check for bad packets */
if (msg.ifm_type == RTM_IFINFO) {
rtbsd_report_change(&msg);
}
} else if (errno == EAGAIN) {
return;
} else {
if (errno == ENOBUFS) {
VLOG_WARN_RL(&rl, "PF_ROUTE receive buffer overflowed");
} else {
VLOG_WARN_RL(&rl, "error reading PF_ROUTE socket: %s",
strerror(errno));
}
rtbsd_report_notify_error();
}
}
}
/* Causes poll_block() to wake up when network device change notifications are
* ready. */
void
rtbsd_notifier_wait(void)
{
if (notify_sock >= 0) {
poll_fd_wait(notify_sock, POLLIN);
}
}
static void
rtbsd_report_change(const struct if_msghdr *msg)
{
struct rtbsd_notifier *notifier;
struct rtbsd_change change;
COVERAGE_INC(rtbsd_changed);
change.msg_type = msg->ifm_type; //XXX
change.if_index = msg->ifm_index;
if_indextoname(msg->ifm_index, change.if_name);
change.master_ifindex = 0; //XXX
LIST_FOR_EACH (notifier, node, &all_notifiers) {
notifier->cb(&change, notifier->aux);
}
}
/* If an error occurs the notifiers' callbacks are called with NULL changes */
static void
rtbsd_report_notify_error(void)
{
struct rtbsd_notifier *notifier;
LIST_FOR_EACH (notifier, node, &all_notifiers) {
notifier->cb(NULL, notifier->aux);
}
}
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