SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/ipv6/netfilter/ip6table_filter.c

   1 /*
   2  * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
   3  *
   4  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
   5  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/netfilter_ipv6/ip6_tables.h>
  15
  16 MODULE_LICENSE("GPL");
  17 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
  18 MODULE_DESCRIPTION("ip6tables filter table");
  19
  20 #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
  21                             (1 << NF_INET_FORWARD) | \
  22                             (1 << NF_INET_LOCAL_OUT))
  23
  24 static struct
  25 {
  26         struct ip6t_replace repl;
  27         struct ip6t_standard entries[3];
  28         struct ip6t_error term;
  29 } initial_table __initdata = {
  30         .repl = {
  31                 .name = "filter",
  32                 .valid_hooks = FILTER_VALID_HOOKS,
  33                 .num_entries = 4,
  34                 .size = sizeof(struct ip6t_standard) * 3 + sizeof(struct ip6t_error),
  35                 .hook_entry = {
  36                         [NF_INET_LOCAL_IN] = 0,
  37                         [NF_INET_FORWARD] = sizeof(struct ip6t_standard),
  38                         [NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2
  39                 },
  40                 .underflow = {
  41                         [NF_INET_LOCAL_IN] = 0,
  42                         [NF_INET_FORWARD] = sizeof(struct ip6t_standard),
  43                         [NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2
  44                 },
  45         },
  46         .entries = {
  47                 IP6T_STANDARD_INIT(NF_ACCEPT),  /* LOCAL_IN */
  48                 IP6T_STANDARD_INIT(NF_ACCEPT),  /* FORWARD */
  49                 IP6T_STANDARD_INIT(NF_ACCEPT),  /* LOCAL_OUT */
  50         },
  51         .term = IP6T_ERROR_INIT,                /* ERROR */
  52 };
  53
  54 static struct xt_table packet_filter = {
  55         .name           = "filter",
  56         .valid_hooks    = FILTER_VALID_HOOKS,
  57         .lock           = RW_LOCK_UNLOCKED,
  58         .me             = THIS_MODULE,
  59         .af             = AF_INET6,
  60 };
  61
  62 /* The work comes in here from netfilter.c. */
  63 static unsigned int
  64 ip6t_hook(unsigned int hook,
  65          struct sk_buff *skb,
  66          const struct net_device *in,
  67          const struct net_device *out,
  68          int (*okfn)(struct sk_buff *))
  69 {
  70         return ip6t_do_table(skb, hook, in, out, &packet_filter);
  71 }
  72
  73 static unsigned int
  74 ip6t_local_out_hook(unsigned int hook,
  75                    struct sk_buff *skb,
  76                    const struct net_device *in,
  77                    const struct net_device *out,
  78                    int (*okfn)(struct sk_buff *))
  79 {
  80 #if 0
  81         /* root is playing with raw sockets. */
  82         if (skb->len < sizeof(struct iphdr)
  83             || ip_hdrlen(skb) < sizeof(struct iphdr)) {
  84                 if (net_ratelimit())
  85                         printk("ip6t_hook: happy cracking.\n");
  86                 return NF_ACCEPT;
  87         }
  88 #endif
  89
  90         return ip6t_do_table(skb, hook, in, out, &packet_filter);
  91 }
  92
  93 static struct nf_hook_ops ip6t_ops[] = {
  94         {
  95                 .hook           = ip6t_hook,
  96                 .owner          = THIS_MODULE,
  97                 .pf             = PF_INET6,
  98                 .hooknum        = NF_INET_LOCAL_IN,
  99                 .priority       = NF_IP6_PRI_FILTER,
 100         },
 101         {
 102                 .hook           = ip6t_hook,
 103                 .owner          = THIS_MODULE,
 104                 .pf             = PF_INET6,
 105                 .hooknum        = NF_INET_FORWARD,
 106                 .priority       = NF_IP6_PRI_FILTER,
 107         },
 108         {
 109                 .hook           = ip6t_local_out_hook,
 110                 .owner          = THIS_MODULE,
 111                 .pf             = PF_INET6,
 112                 .hooknum        = NF_INET_LOCAL_OUT,
 113                 .priority       = NF_IP6_PRI_FILTER,
 114         },
 115 };
 116
 117 /* Default to forward because I got too much mail already. */
 118 static int forward = NF_ACCEPT;
 119 module_param(forward, bool, 0000);
 120
 121 static int __init ip6table_filter_init(void)
 122 {
 123         int ret;
 124
 125         if (forward < 0 || forward > NF_MAX_VERDICT) {
 126                 printk("iptables forward must be 0 or 1\n");
 127                 return -EINVAL;
 128         }
 129
 130         /* Entry 1 is the FORWARD hook */
 131         initial_table.entries[1].target.verdict = -forward - 1;
 132
 133         /* Register table */
 134         ret = ip6t_register_table(&packet_filter, &initial_table.repl);
 135         if (ret < 0)
 136                 return ret;
 137
 138         /* Register hooks */
 139         ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
 140         if (ret < 0)
 141                 goto cleanup_table;
 142
 143         return ret;
 144
 145  cleanup_table:
 146         ip6t_unregister_table(&packet_filter);
 147         return ret;
 148 }
 149
 150 static void __exit ip6table_filter_fini(void)
 151 {
 152         nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
 153         ip6t_unregister_table(&packet_filter);
 154 }
 155
 156 module_init(ip6table_filter_init);
 157 module_exit(ip6table_filter_fini);