[NET]: Network Event Notifier Mechanism.

#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);