net/bridge/netfilter/ebtable_filter.c

   1 /*
   2  *  ebtable_filter
   3  *
   4  *      Authors:
   5  *      Bart De Schuymer <bdschuym@pandora.be>
   6  *
   7  *  April, 2002
   8  *
   9  */
  10
  11 #include <linux/netfilter_bridge/ebtables.h>
  12 #include <linux/module.h>
  13
  14 #define FILTER_VALID_HOOKS ((1 << NF_BR_LOCAL_IN) | (1 << NF_BR_FORWARD) | \
  15    (1 << NF_BR_LOCAL_OUT))
  16
  17 static struct ebt_entries initial_chains[] =
  18 {
  19         {
  20                 .name   = "INPUT",
  21                 .policy = EBT_ACCEPT,
  22         },
  23         {
  24                 .name   = "FORWARD",
  25                 .policy = EBT_ACCEPT,
  26         },
  27         {
  28                 .name   = "OUTPUT",
  29                 .policy = EBT_ACCEPT,
  30         },
  31 };
  32
  33 static struct ebt_replace_kernel initial_table =
  34 {
  35         .name           = "filter",
  36         .valid_hooks    = FILTER_VALID_HOOKS,
  37         .entries_size   = 3 * sizeof(struct ebt_entries),
  38         .hook_entry     = {
  39                 [NF_BR_LOCAL_IN]        = &initial_chains[0],
  40                 [NF_BR_FORWARD]         = &initial_chains[1],
  41                 [NF_BR_LOCAL_OUT]       = &initial_chains[2],
  42         },
  43         .entries        = (char *)initial_chains,
  44 };
  45
  46 static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
  47 {
  48         if (valid_hooks & ~FILTER_VALID_HOOKS)
  49                 return -EINVAL;
  50         return 0;
  51 }
  52
  53 static struct ebt_table frame_filter =
  54 {
  55         .name           = "filter",
  56         .table          = &initial_table,
  57         .valid_hooks    = FILTER_VALID_HOOKS,
  58         .lock           = RW_LOCK_UNLOCKED,
  59         .check          = check,
  60         .me             = THIS_MODULE,
  61 };
  62
  63 static unsigned int
  64 ebt_hook (unsigned int hook, struct sk_buff **pskb, const struct net_device *in,
  65    const struct net_device *out, int (*okfn)(struct sk_buff *))
  66 {
  67         return ebt_do_table(hook, pskb, in, out, &frame_filter);
  68 }
  69
  70 static struct nf_hook_ops ebt_ops_filter[] = {
  71         {
  72                 .hook           = ebt_hook,
  73                 .owner          = THIS_MODULE,
  74                 .pf             = PF_BRIDGE,
  75                 .hooknum        = NF_BR_LOCAL_IN,
  76                 .priority       = NF_BR_PRI_FILTER_BRIDGED,
  77         },
  78         {
  79                 .hook           = ebt_hook,
  80                 .owner          = THIS_MODULE,
  81                 .pf             = PF_BRIDGE,
  82                 .hooknum        = NF_BR_FORWARD,
  83                 .priority       = NF_BR_PRI_FILTER_BRIDGED,
  84         },
  85         {
  86                 .hook           = ebt_hook,
  87                 .owner          = THIS_MODULE,
  88                 .pf             = PF_BRIDGE,
  89                 .hooknum        = NF_BR_LOCAL_OUT,
  90                 .priority       = NF_BR_PRI_FILTER_OTHER,
  91         },
  92 };
  93
  94 static int __init ebtable_filter_init(void)
  95 {
  96         int i, j, ret;
  97
  98         ret = ebt_register_table(&frame_filter);
  99         if (ret < 0)
 100                 return ret;
 101         for (i = 0; i < ARRAY_SIZE(ebt_ops_filter); i++)
 102                 if ((ret = nf_register_hook(&ebt_ops_filter[i])) < 0)
 103                         goto cleanup;
 104         return ret;
 105 cleanup:
 106         for (j = 0; j < i; j++)
 107                 nf_unregister_hook(&ebt_ops_filter[j]);
 108         ebt_unregister_table(&frame_filter);
 109         return ret;
 110 }
 111
 112 static void __exit ebtable_filter_fini(void)
 113 {
 114         int i;
 115
 116         for (i = 0; i < ARRAY_SIZE(ebt_ops_filter); i++)
 117                 nf_unregister_hook(&ebt_ops_filter[i]);
 118         ebt_unregister_table(&frame_filter);
 119 }
 120
 121 module_init(ebtable_filter_init);
 122 module_exit(ebtable_filter_fini);
 123 MODULE_LICENSE("GPL");