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/*
* Copyright (c) 2009, 2010, 2011 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 <poll.h>
#include <stdlib.h>
#include "coverage.h"
#include "netlink.h"
#include "netlink-socket.h"
#include "ofpbuf.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(rtnetlink);
COVERAGE_DEFINE(rtnetlink_changed);
static void rtnetlink_report(struct rtnetlink *rtn, void *change);
struct rtnetlink {
struct nl_sock *notify_sock; /* Rtnetlink socket. */
struct list all_notifiers; /* All rtnetlink notifiers. */
/* Passed in by rtnetlink_create(). */
int multicast_group; /* Multicast group we listen on. */
rtnetlink_parse_func *parse; /* Message parsing function. */
void *change; /* Change passed to parse. */
};
/* Creates an rtnetlink handle which may be used to manage change
* notifications. The created handle will listen for rtnetlink messages on
* 'multicast_group'. Incoming messages will be parsed with 'parse' which will
* be passed 'change' as an argument. */
struct rtnetlink *
rtnetlink_create(int multicast_group, rtnetlink_parse_func *parse,
void *change)
{
struct rtnetlink *rtn;
rtn = xzalloc(sizeof *rtn);
rtn->notify_sock = 0;
rtn->multicast_group = multicast_group;
rtn->parse = parse;
rtn->change = change;
list_init(&rtn->all_notifiers);
return rtn;
}
/* Destroys 'rtn' by freeing any memory it has reserved and closing any sockets
* it has opened. */
void
rtnetlink_destroy(struct rtnetlink *rtn)
{
if (rtn) {
nl_sock_destroy(rtn->notify_sock);
free(rtn);
}
}
/* Registers 'cb' to be called with auxiliary data 'aux' with change
* notifications. The notifier is stored in 'notifier', which the caller must
* not modify or free.
*
* This is probably not the function you want. You should probably be using
* message specific notifiers like rtnetlink_link_notifier_register().
*
* Returns 0 if successful, otherwise a positive errno value. */
int
rtnetlink_notifier_register(struct rtnetlink *rtn,
struct rtnetlink_notifier *notifier,
rtnetlink_notify_func *cb, void *aux)
{
if (!rtn->notify_sock) {
struct nl_sock *sock;
int error;
error = nl_sock_create(NETLINK_ROUTE, &sock);
if (!error) {
error = nl_sock_join_mcgroup(sock, rtn->multicast_group);
}
if (error) {
nl_sock_destroy(sock);
VLOG_WARN("could not create rtnetlink socket: %s",
strerror(error));
return error;
}
rtn->notify_sock = sock;
} else {
/* Catch up on notification work so that the new notifier won't
* receive any stale notifications. */
rtnetlink_notifier_run(rtn);
}
list_push_back(&rtn->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 *rtn,
struct rtnetlink_notifier *notifier)
{
list_remove(¬ifier->node);
if (list_is_empty(&rtn->all_notifiers)) {
nl_sock_destroy(rtn->notify_sock);
rtn->notify_sock = NULL;
}
}
/* Calls all of the registered notifiers, passing along any as-yet-unreported
* change events. */
void
rtnetlink_notifier_run(struct rtnetlink *rtn)
{
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
if (!rtn->notify_sock) {
return;
}
for (;;) {
struct ofpbuf *buf;
int error;
error = nl_sock_recv(rtn->notify_sock, &buf, false);
if (!error) {
if (rtn->parse(buf, rtn->change)) {
rtnetlink_report(rtn, rtn->change);
} else {
VLOG_WARN_RL(&rl, "received bad rtnl message");
rtnetlink_report(rtn, NULL);
}
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(rtn, NULL);
}
}
}
/* Causes poll_block() to wake up when change notifications are ready. */
void
rtnetlink_notifier_wait(struct rtnetlink *rtn)
{
if (rtn->notify_sock) {
nl_sock_wait(rtn->notify_sock, POLLIN);
}
}
static void
rtnetlink_report(struct rtnetlink *rtn, void *change)
{
struct rtnetlink_notifier *notifier;
if (change) {
COVERAGE_INC(rtnetlink_changed);
}
LIST_FOR_EACH (notifier, node, &rtn->all_notifiers) {
notifier->cb(change, notifier->aux);
}
}
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