net/bridge/netfilter/ebtable_broute.c

   1 /*
   2  *  ebtable_broute
   3  *
   4  *      Authors:
   5  *      Bart De Schuymer <bdschuym@pandora.be>
   6  *
   7  *  April, 2002
   8  *
   9  *  This table lets you choose between routing and bridging for frames
  10  *  entering on a bridge enslaved nic. This table is traversed before any
  11  *  other ebtables table. See net/bridge/br_input.c.
  12  */
  13
  14 #include <linux/netfilter_bridge/ebtables.h>
  15 #include <linux/module.h>
  16 #include <linux/if_bridge.h>
  17
  18 /* EBT_ACCEPT means the frame will be bridged
  19  * EBT_DROP means the frame will be routed
  20  */
  21 static struct ebt_entries initial_chain = {
  22         .name           = "BROUTING",
  23         .policy         = EBT_ACCEPT,
  24 };
  25
  26 static struct ebt_replace_kernel initial_table =
  27 {
  28         .name           = "broute",
  29         .valid_hooks    = 1 << NF_BR_BROUTING,
  30         .entries_size   = sizeof(struct ebt_entries),
  31         .hook_entry     = {
  32                 [NF_BR_BROUTING]        = &initial_chain,
  33         },
  34         .entries        = (char *)&initial_chain,
  35 };
  36
  37 static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
  38 {
  39         if (valid_hooks & ~(1 << NF_BR_BROUTING))
  40                 return -EINVAL;
  41         return 0;
  42 }
  43
  44 static struct ebt_table broute_table =
  45 {
  46         .name           = "broute",
  47         .table          = &initial_table,
  48         .valid_hooks    = 1 << NF_BR_BROUTING,
  49         .lock           = __RW_LOCK_UNLOCKED(broute_table.lock),
  50         .check          = check,
  51         .me             = THIS_MODULE,
  52 };
  53
  54 static int ebt_broute(struct sk_buff *skb)
  55 {
  56         int ret;
  57
  58         ret = ebt_do_table(NF_BR_BROUTING, skb, skb->dev, NULL,
  59                            dev_net(skb->dev)->xt.broute_table);
  60         if (ret == NF_DROP)
  61                 return 1; /* route it */
  62         return 0; /* bridge it */
  63 }
  64
  65 static int __net_init broute_net_init(struct net *net)
  66 {
  67         net->xt.broute_table = ebt_register_table(net, &broute_table);
  68         if (IS_ERR(net->xt.broute_table))
  69                 return PTR_ERR(net->xt.broute_table);
  70         return 0;
  71 }
  72
  73 static void __net_exit broute_net_exit(struct net *net)
  74 {
  75         ebt_unregister_table(net->xt.broute_table);
  76 }
  77
  78 static struct pernet_operations broute_net_ops = {
  79         .init = broute_net_init,
  80         .exit = broute_net_exit,
  81 };
  82
  83 static int __init ebtable_broute_init(void)
  84 {
  85         int ret;
  86
  87         ret = register_pernet_subsys(&broute_net_ops);
  88         if (ret < 0)
  89                 return ret;
  90         /* see br_input.c */
  91         rcu_assign_pointer(br_should_route_hook, ebt_broute);
  92         return 0;
  93 }
  94
  95 static void __exit ebtable_broute_fini(void)
  96 {
  97         rcu_assign_pointer(br_should_route_hook, NULL);
  98         synchronize_net();
  99         unregister_pernet_subsys(&broute_net_ops);
 100 }
 101
 102 module_init(ebtable_broute_init);
 103 module_exit(ebtable_broute_fini);
 104 MODULE_LICENSE("GPL");