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

[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

include/net/netevent.h

0 → 100644
+33 −0
Original line number Diff line number Diff line 
#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

net/core/netevent.c

0 → 100644
+69 −0
Original line number Diff line number Diff line 
/*

 *	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);