release/src-rt-6.x.4708/linux/linux-2.6.36/net/core/netevent.c

   1 /*
   2  *      Network event notifiers
   3  *
   4  *      Authors:
   5  *      Tom Tucker             <tom@opengridcomputing.com>
   6  *      Steve Wise             <swise@opengridcomputing.com>
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  *
  13  *      Fixes:
  14  */
  15
  16 #include <linux/rtnetlink.h>
  17 #include <linux/notifier.h>
  18 #include <net/netevent.h>
  19
  20 static ATOMIC_NOTIFIER_HEAD(netevent_notif_chain);
  21
  22 /**
  23  *      register_netevent_notifier - register a netevent notifier block
  24  *      @nb: notifier
  25  *
  26  *      Register a notifier to be called when a netevent occurs.
  27  *      The notifier passed is linked into the kernel structures and must
  28  *      not be reused until it has been unregistered. A negative errno code
  29  *      is returned on a failure.
  30  */
  31 int register_netevent_notifier(struct notifier_block *nb)
  32 {
  33         int err;
  34
  35         err = atomic_notifier_chain_register(&netevent_notif_chain, nb);
  36         return err;
  37 }
  38 EXPORT_SYMBOL_GPL(register_netevent_notifier);
  39
  40 /**
  41  *      netevent_unregister_notifier - unregister a netevent notifier block
  42  *      @nb: notifier
  43  *
  44  *      Unregister a notifier previously registered by
  45  *      register_neigh_notifier(). The notifier is unlinked into the
  46  *      kernel structures and may then be reused. A negative errno code
  47  *      is returned on a failure.
  48  */
  49
  50 int unregister_netevent_notifier(struct notifier_block *nb)
  51 {
  52         return atomic_notifier_chain_unregister(&netevent_notif_chain, nb);
  53 }
  54 EXPORT_SYMBOL_GPL(unregister_netevent_notifier);
  55
  56 /**
  57  *      call_netevent_notifiers - call all netevent notifier blocks
  58  *      @val: value passed unmodified to notifier function
  59  *      @v:   pointer passed unmodified to notifier function
  60  *
  61  *      Call all neighbour notifier blocks.  Parameters and return value
  62  *      are as for notifier_call_chain().
  63  */
  64
  65 int call_netevent_notifiers(unsigned long val, void *v)
  66 {
  67         return atomic_notifier_call_chain(&netevent_notif_chain, val, v);
  68 }
  69 EXPORT_SYMBOL_GPL(call_netevent_notifiers);