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
  19 static ATOMIC_NOTIFIER_HEAD(netevent_notif_chain);
  20
  21 /**
  22  *      register_netevent_notifier - register a netevent notifier block
  23  *      @nb: notifier
  24  *
  25  *      Register a notifier to be called when a netevent occurs.
  26  *      The notifier passed is linked into the kernel structures and must
  27  *      not be reused until it has been unregistered. A negative errno code
  28  *      is returned on a failure.
  29  */
  30 int register_netevent_notifier(struct notifier_block *nb)
  31 {
  32         int err;
  33
  34         err = atomic_notifier_chain_register(&netevent_notif_chain, nb);
  35         return err;
  36 }
  37
  38 /**
  39  *      netevent_unregister_notifier - unregister a netevent notifier block
  40  *      @nb: notifier
  41  *
  42  *      Unregister a notifier previously registered by
  43  *      register_neigh_notifier(). The notifier is unlinked into the
  44  *      kernel structures and may then be reused. A negative errno code
  45  *      is returned on a failure.
  46  */
  47
  48 int unregister_netevent_notifier(struct notifier_block *nb)
  49 {
  50         return atomic_notifier_chain_unregister(&netevent_notif_chain, nb);
  51 }
  52
  53 /**
  54  *      call_netevent_notifiers - call all netevent notifier blocks
  55  *      @val: value passed unmodified to notifier function
  56  *      @v:   pointer passed unmodified to notifier function
  57  *
  58  *      Call all neighbour notifier blocks.  Parameters and return value
  59  *      are as for notifier_call_chain().
  60  */
  61
  62 int call_netevent_notifiers(unsigned long val, void *v)
  63 {
  64         return atomic_notifier_call_chain(&netevent_notif_chain, val, v);
  65 }
  66
  67 EXPORT_SYMBOL_GPL(register_netevent_notifier);
  68 EXPORT_SYMBOL_GPL(unregister_netevent_notifier);
  69 EXPORT_SYMBOL_GPL(call_netevent_notifiers);