Commit 792d1932 authored by Tom Tucker's avatar Tom Tucker Committed by David S. Miller

[NET]: Network Event Notifier Mechanism.

This patch uses notifier blocks to implement a network event
notifier mechanism.

Clients register their callback function by calling
register_netevent_notifier() like this:

static struct notifier_block nb = {
        .notifier_call = my_callback_func
};

...

register_netevent_notifier(&nb);
Signed-off-by: default avatarTom Tucker <tom@opengridcomputing.com>
Signed-off-by: default avatarSteve Wise <swise@opengridcomputing.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3687b1dc
#ifndef _NET_EVENT_H
#define _NET_EVENT_H
/*
* Generic netevent notifiers
*
* Authors:
* Tom Tucker <tom@opengridcomputing.com>
* Steve Wise <swise@opengridcomputing.com>
*
* Changes:
*/
#ifdef __KERNEL__
#include <net/dst.h>
struct netevent_redirect {
struct dst_entry *old;
struct dst_entry *new;
};
enum netevent_notif_type {
NETEVENT_NEIGH_UPDATE = 1, /* arg is struct neighbour ptr */
NETEVENT_PMTU_UPDATE, /* arg is struct dst_entry ptr */
NETEVENT_REDIRECT, /* arg is struct netevent_redirect ptr */
};
extern int register_netevent_notifier(struct notifier_block *nb);
extern int unregister_netevent_notifier(struct notifier_block *nb);
extern int call_netevent_notifiers(unsigned long val, void *v);
#endif
#endif
/*
* Network event notifiers
*
* Authors:
* Tom Tucker <tom@opengridcomputing.com>
* Steve Wise <swise@opengridcomputing.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Fixes:
*/
#include <linux/rtnetlink.h>
#include <linux/notifier.h>
static ATOMIC_NOTIFIER_HEAD(netevent_notif_chain);
/**
* register_netevent_notifier - register a netevent notifier block
* @nb: notifier
*
* Register a notifier to be called when a netevent occurs.
* The notifier passed is linked into the kernel structures and must
* not be reused until it has been unregistered. A negative errno code
* is returned on a failure.
*/
int register_netevent_notifier(struct notifier_block *nb)
{
int err;
err = atomic_notifier_chain_register(&netevent_notif_chain, nb);
return err;
}
/**
* netevent_unregister_notifier - unregister a netevent notifier block
* @nb: notifier
*
* Unregister a notifier previously registered by
* register_neigh_notifier(). The notifier is unlinked into the
* kernel structures and may then be reused. A negative errno code
* is returned on a failure.
*/
int unregister_netevent_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&netevent_notif_chain, nb);
}
/**
* call_netevent_notifiers - call all netevent notifier blocks
* @val: value passed unmodified to notifier function
* @v: pointer passed unmodified to notifier function
*
* Call all neighbour notifier blocks. Parameters and return value
* are as for notifier_call_chain().
*/
int call_netevent_notifiers(unsigned long val, void *v)
{
return atomic_notifier_call_chain(&netevent_notif_chain, val, v);
}
EXPORT_SYMBOL_GPL(register_netevent_notifier);
EXPORT_SYMBOL_GPL(unregister_netevent_notifier);
EXPORT_SYMBOL_GPL(call_netevent_notifiers);
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