net/ipv4/fib_notifier.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/rtnetlink.h>
   3 #include <linux/notifier.h>
   4 #include <linux/socket.h>
   5 #include <linux/kernel.h>
   6 #include <linux/export.h>
   7 #include <net/net_namespace.h>
   8 #include <net/fib_notifier.h>
   9 #include <net/ip_fib.h>
  10
  11 int call_fib4_notifier(struct notifier_block *nb,
  12                        enum fib_event_type event_type,
  13                        struct fib_notifier_info *info)
  14 {
  15         info->family = AF_INET;
  16         return call_fib_notifier(nb, event_type, info);
  17 }
  18
  19 int call_fib4_notifiers(struct net *net, enum fib_event_type event_type,
  20                         struct fib_notifier_info *info)
  21 {
  22         ASSERT_RTNL();
  23
  24         info->family = AF_INET;
  25         /* Paired with READ_ONCE() in fib4_seq_read() */
  26         WRITE_ONCE(net->ipv4.fib_seq, net->ipv4.fib_seq + 1);
  27         return call_fib_notifiers(net, event_type, info);
  28 }
  29
  30 static unsigned int fib4_seq_read(const struct net *net)
  31 {
  32         /* Paired with WRITE_ONCE() in call_fib4_notifiers() */
  33         return READ_ONCE(net->ipv4.fib_seq) + fib4_rules_seq_read(net);
  34 }
  35
  36 static int fib4_dump(struct net *net, struct notifier_block *nb,
  37                      struct netlink_ext_ack *extack)
  38 {
  39         int err;
  40
  41         err = fib4_rules_dump(net, nb, extack);
  42         if (err)
  43                 return err;
  44
  45         return fib_notify(net, nb, extack);
  46 }
  47
  48 static const struct fib_notifier_ops fib4_notifier_ops_template = {
  49         .family         = AF_INET,
  50         .fib_seq_read   = fib4_seq_read,
  51         .fib_dump       = fib4_dump,
  52         .owner          = THIS_MODULE,
  53 };
  54
  55 int __net_init fib4_notifier_init(struct net *net)
  56 {
  57         struct fib_notifier_ops *ops;
  58
  59         net->ipv4.fib_seq = 0;
  60
  61         ops = fib_notifier_ops_register(&fib4_notifier_ops_template, net);
  62         if (IS_ERR(ops))
  63                 return PTR_ERR(ops);
  64         net->ipv4.notifier_ops = ops;
  65
  66         return 0;
  67 }
  68
  69 void __net_exit fib4_notifier_exit(struct net *net)
  70 {
  71         fib_notifier_ops_unregister(net->ipv4.notifier_ops);
  72 }