net/core/netevent.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Network event notifiers
   4  *
   5  *      Authors:
   6  *      Tom Tucker             <tom@opengridcomputing.com>
   7  *      Steve Wise             <swise@opengridcomputing.com>
   8  *
   9  *      Fixes:
  10  */
  11
  12 #include <linux/rtnetlink.h>
  13 #include <linux/notifier.h>
  14 #include <linux/export.h>
  15 #include <net/netevent.h>
  16
  17 static ATOMIC_NOTIFIER_HEAD(netevent_notif_chain);
  18
  19 /**
  20  *      register_netevent_notifier - register a netevent notifier block
  21  *      @nb: notifier
  22  *
  23  *      Register a notifier to be called when a netevent occurs.
  24  *      The notifier passed is linked into the kernel structures and must
  25  *      not be reused until it has been unregistered. A negative errno code
  26  *      is returned on a failure.
  27  */
  28 int register_netevent_notifier(struct notifier_block *nb)
  29 {
  30         return atomic_notifier_chain_register(&netevent_notif_chain, nb);
  31 }
  32 EXPORT_SYMBOL_GPL(register_netevent_notifier);
  33
  34 /**
  35  *      unregister_netevent_notifier - unregister a netevent notifier block
  36  *      @nb: notifier
  37  *
  38  *      Unregister a notifier previously registered by
  39  *      register_neigh_notifier(). The notifier is unlinked into the
  40  *      kernel structures and may then be reused. A negative errno code
  41  *      is returned on a failure.
  42  */
  43
  44 int unregister_netevent_notifier(struct notifier_block *nb)
  45 {
  46         return atomic_notifier_chain_unregister(&netevent_notif_chain, nb);
  47 }
  48 EXPORT_SYMBOL_GPL(unregister_netevent_notifier);
  49
  50 /**
  51  *      call_netevent_notifiers - call all netevent notifier blocks
  52  *      @val: value passed unmodified to notifier function
  53  *      @v:   pointer passed unmodified to notifier function
  54  *
  55  *      Call all neighbour notifier blocks.  Parameters and return value
  56  *      are as for notifier_call_chain().
  57  */
  58
  59 int call_netevent_notifiers(unsigned long val, void *v)
  60 {
  61         return atomic_notifier_call_chain(&netevent_notif_chain, val, v);
  62 }
  63 EXPORT_SYMBOL_GPL(call_netevent_notifiers);