release/src-rt-6.x/linux/linux-2.6/net/ipv4/netfilter/arptable_filter.c

   1 /*
   2  * Filtering ARP tables module.
   3  *
   4  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   5  *
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/netfilter_arp/arp_tables.h>
  10
  11 MODULE_LICENSE("GPL");
  12 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  13 MODULE_DESCRIPTION("arptables filter table");
  14
  15 #define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
  16                            (1 << NF_ARP_FORWARD))
  17
  18 static struct
  19 {
  20         struct arpt_replace repl;
  21         struct arpt_standard entries[3];
  22         struct arpt_error term;
  23 } initial_table __initdata = {
  24         .repl = {
  25                 .name = "filter",
  26                 .valid_hooks = FILTER_VALID_HOOKS,
  27                 .num_entries = 4,
  28                 .size = sizeof(struct arpt_standard) * 3 + sizeof(struct arpt_error),
  29                 .hook_entry = {
  30                         [NF_ARP_IN] = 0,
  31                         [NF_ARP_OUT] = sizeof(struct arpt_standard),
  32                         [NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard),
  33                 },
  34                 .underflow = {
  35                         [NF_ARP_IN] = 0,
  36                         [NF_ARP_OUT] = sizeof(struct arpt_standard),
  37                         [NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard),
  38                 },
  39         },
  40         .entries = {
  41                 ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_IN */
  42                 ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_OUT */
  43                 ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_FORWARD */
  44         },
  45         .term = ARPT_ERROR_INIT,
  46 };
  47
  48 static struct arpt_table packet_filter = {
  49         .name           = "filter",
  50         .valid_hooks    = FILTER_VALID_HOOKS,
  51         .me             = THIS_MODULE,
  52         .af             = NF_ARP,
  53 };
  54
  55 /* The work comes in here from netfilter.c */
  56 static unsigned int arpt_hook(unsigned int hook,
  57                               struct sk_buff *skb,
  58                               const struct net_device *in,
  59                               const struct net_device *out,
  60                               int (*okfn)(struct sk_buff *))
  61 {
  62         return arpt_do_table(skb, hook, in, out, &packet_filter);
  63 }
  64
  65 static struct nf_hook_ops arpt_ops[] = {
  66         {
  67                 .hook           = arpt_hook,
  68                 .owner          = THIS_MODULE,
  69                 .pf             = NF_ARP,
  70                 .hooknum        = NF_ARP_IN,
  71         },
  72         {
  73                 .hook           = arpt_hook,
  74                 .owner          = THIS_MODULE,
  75                 .pf             = NF_ARP,
  76                 .hooknum        = NF_ARP_OUT,
  77         },
  78         {
  79                 .hook           = arpt_hook,
  80                 .owner          = THIS_MODULE,
  81                 .pf             = NF_ARP,
  82                 .hooknum        = NF_ARP_FORWARD,
  83         },
  84 };
  85
  86 static int __init arptable_filter_init(void)
  87 {
  88         int ret;
  89
  90         /* Register table */
  91         ret = arpt_register_table(&packet_filter, &initial_table.repl);
  92         if (ret < 0)
  93                 return ret;
  94
  95         ret = nf_register_hooks(arpt_ops, ARRAY_SIZE(arpt_ops));
  96         if (ret < 0)
  97                 goto cleanup_table;
  98         return ret;
  99
 100 cleanup_table:
 101         arpt_unregister_table(&packet_filter);
 102         return ret;
 103 }
 104
 105 static void __exit arptable_filter_fini(void)
 106 {
 107         nf_unregister_hooks(arpt_ops, ARRAY_SIZE(arpt_ops));
 108         arpt_unregister_table(&packet_filter);
 109 }
 110
 111 module_init(arptable_filter_init);
 112 module_exit(arptable_filter_fini);