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         .name           = "broute",
  28         .valid_hooks    = 1 << NF_BR_BROUTING,
  29         .entries_size   = sizeof(struct ebt_entries),
  30         .hook_entry     = {
  31                 [NF_BR_BROUTING]        = &initial_chain,
  32         },
  33         .entries        = (char *)&initial_chain,
  34 };
  35
  36 static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
  37 {
  38         if (valid_hooks & ~(1 << NF_BR_BROUTING))
  39                 return -EINVAL;
  40         return 0;
  41 }
  42
  43 static const struct ebt_table broute_table = {
  44         .name           = "broute",
  45         .table          = &initial_table,
  46         .valid_hooks    = 1 << NF_BR_BROUTING,
  47         .check          = check,
  48         .me             = THIS_MODULE,
  49 };
  50
  51 static int ebt_broute(struct sk_buff *skb)
  52 {
  53         struct nf_hook_state state;
  54         int ret;
  55
  56         nf_hook_state_init(&state, NULL, NF_BR_BROUTING,
  57                            NFPROTO_BRIDGE, skb->dev, NULL, NULL,
  58                            dev_net(skb->dev), NULL);
  59
  60         ret = ebt_do_table(skb, &state, state.net->xt.broute_table);
  61         if (ret == NF_DROP)
  62                 return 1; /* route it */
  63         return 0; /* bridge it */
  64 }
  65
  66 static int __net_init broute_net_init(struct net *net)
  67 {
  68         net->xt.broute_table = ebt_register_table(net, &broute_table);
  69         return PTR_ERR_OR_ZERO(net->xt.broute_table);
  70 }
  71
  72 static void __net_exit broute_net_exit(struct net *net)
  73 {
  74         ebt_unregister_table(net, net->xt.broute_table);
  75 }
  76
  77 static struct pernet_operations broute_net_ops = {
  78         .init = broute_net_init,
  79         .exit = broute_net_exit,
  80 };
  81
  82 static int __init ebtable_broute_init(void)
  83 {
  84         int ret;
  85
  86         ret = register_pernet_subsys(&broute_net_ops);
  87         if (ret < 0)
  88                 return ret;
  89         /* see br_input.c */
  90         RCU_INIT_POINTER(br_should_route_hook,
  91                            (br_should_route_hook_t *)ebt_broute);
  92         return 0;
  93 }
  94
  95 static void __exit ebtable_broute_fini(void)
  96 {
  97         RCU_INIT_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");