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 const struct ebt_table broute_table =
  45 {
  46         .name           = "broute",
  47         .table          = &initial_table,
  48         .valid_hooks    = 1 << NF_BR_BROUTING,
  49         .check          = check,
  50         .me             = THIS_MODULE,
  51 };
  52
  53 static int ebt_broute(struct sk_buff *skb)
  54 {
  55         int ret;
  56
  57         ret = ebt_do_table(NF_BR_BROUTING, skb, skb->dev, NULL,
  58                            dev_net(skb->dev)->xt.broute_table);
  59         if (ret == NF_DROP)
  60                 return 1; /* route it */
  61         return 0; /* bridge it */
  62 }
  63
  64 static int __net_init broute_net_init(struct net *net)
  65 {
  66         net->xt.broute_table = ebt_register_table(net, &broute_table);
  67         return PTR_ERR_OR_ZERO(net->xt.broute_table);
  68 }
  69
  70 static void __net_exit broute_net_exit(struct net *net)
  71 {
  72         ebt_unregister_table(net, net->xt.broute_table);
  73 }
  74
  75 static struct pernet_operations broute_net_ops = {
  76         .init = broute_net_init,
  77         .exit = broute_net_exit,
  78 };
  79
  80 static int __init ebtable_broute_init(void)
  81 {
  82         int ret;
  83
  84         ret = register_pernet_subsys(&broute_net_ops);
  85         if (ret < 0)
  86                 return ret;
  87         /* see br_input.c */
  88         RCU_INIT_POINTER(br_should_route_hook,
  89                            (br_should_route_hook_t *)ebt_broute);
  90         return 0;
  91 }
  92
  93 static void __exit ebtable_broute_fini(void)
  94 {
  95         RCU_INIT_POINTER(br_should_route_hook, NULL);
  96         synchronize_net();
  97         unregister_pernet_subsys(&broute_net_ops);
  98 }
  99
 100 module_init(ebtable_broute_init);
 101 module_exit(ebtable_broute_fini);
 102 MODULE_LICENSE("GPL");