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/netfilter_ipv6/ip6_tables.h>
  14
  15 MODULE_LICENSE("GPL");
  16 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
  17 MODULE_DESCRIPTION("ip6tables filter table");
  18
  19 #define FILTER_VALID_HOOKS ((1 << NF_IP6_LOCAL_IN) | (1 << NF_IP6_FORWARD) | (1 << NF_IP6_LOCAL_OUT))
  20
  21 /* Standard entry. */
  22 struct ip6t_standard
  23 {
  24         struct ip6t_entry entry;
  25         struct ip6t_standard_target target;
  26 };
  27
  28 struct ip6t_error_target
  29 {
  30         struct ip6t_entry_target target;
  31         char errorname[IP6T_FUNCTION_MAXNAMELEN];
  32 };
  33
  34 struct ip6t_error
  35 {
  36         struct ip6t_entry entry;
  37         struct ip6t_error_target target;
  38 };
  39
  40 static struct
  41 {
  42         struct ip6t_replace repl;
  43         struct ip6t_standard entries[3];
  44         struct ip6t_error term;
  45 } initial_table __initdata
  46 = { { "filter", FILTER_VALID_HOOKS, 4,
  47       sizeof(struct ip6t_standard) * 3 + sizeof(struct ip6t_error),
  48       { [NF_IP6_LOCAL_IN] = 0,
  49         [NF_IP6_FORWARD] = sizeof(struct ip6t_standard),
  50         [NF_IP6_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2 },
  51       { [NF_IP6_LOCAL_IN] = 0,
  52         [NF_IP6_FORWARD] = sizeof(struct ip6t_standard),
  53         [NF_IP6_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2 },
  54       0, NULL, { } },
  55     {
  56             /* LOCAL_IN */
  57             { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },
  58                 0,
  59                 sizeof(struct ip6t_entry),
  60                 sizeof(struct ip6t_standard),
  61                 0, { 0, 0 }, { } },
  62               { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },
  63                 -NF_ACCEPT - 1 } },
  64             /* FORWARD */
  65             { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },
  66                 0,
  67                 sizeof(struct ip6t_entry),
  68                 sizeof(struct ip6t_standard),
  69                 0, { 0, 0 }, { } },
  70               { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },
  71                 -NF_ACCEPT - 1 } },
  72             /* LOCAL_OUT */
  73             { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },
  74                 0,
  75                 sizeof(struct ip6t_entry),
  76                 sizeof(struct ip6t_standard),
  77                 0, { 0, 0 }, { } },
  78               { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },
  79                 -NF_ACCEPT - 1 } }
  80     },
  81     /* ERROR */
  82     { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },
  83         0,
  84         sizeof(struct ip6t_entry),
  85         sizeof(struct ip6t_error),
  86         0, { 0, 0 }, { } },
  87       { { { { IP6T_ALIGN(sizeof(struct ip6t_error_target)), IP6T_ERROR_TARGET } },
  88           { } },
  89         "ERROR"
  90       }
  91     }
  92 };
  93
  94 static struct ip6t_table packet_filter = {
  95         .name           = "filter",
  96         .table          = &initial_table.repl,
  97         .valid_hooks    = FILTER_VALID_HOOKS,
  98         .lock           = RW_LOCK_UNLOCKED,
  99         .me             = THIS_MODULE,
 100 };
 101
 102 /* The work comes in here from netfilter.c. */
 103 static unsigned int
 104 ip6t_hook(unsigned int hook,
 105          struct sk_buff **pskb,
 106          const struct net_device *in,
 107          const struct net_device *out,
 108          int (*okfn)(struct sk_buff *))
 109 {
 110         return ip6t_do_table(pskb, hook, in, out, &packet_filter, NULL);
 111 }
 112
 113 static unsigned int
 114 ip6t_local_out_hook(unsigned int hook,
 115                    struct sk_buff **pskb,
 116                    const struct net_device *in,
 117                    const struct net_device *out,
 118                    int (*okfn)(struct sk_buff *))
 119 {
 120 #if 0
 121         /* root is playing with raw sockets. */
 122         if ((*pskb)->len < sizeof(struct iphdr)
 123             || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {
 124                 if (net_ratelimit())
 125                         printk("ip6t_hook: happy cracking.\n");
 126                 return NF_ACCEPT;
 127         }
 128 #endif
 129
 130         return ip6t_do_table(pskb, hook, in, out, &packet_filter, NULL);
 131 }
 132
 133 static struct nf_hook_ops ip6t_ops[] = {
 134         {
 135                 .hook           = ip6t_hook,
 136                 .owner          = THIS_MODULE,
 137                 .pf             = PF_INET6,
 138                 .hooknum        = NF_IP6_LOCAL_IN,
 139                 .priority       = NF_IP6_PRI_FILTER,
 140         },
 141         {
 142                 .hook           = ip6t_hook,
 143                 .owner          = THIS_MODULE,
 144                 .pf             = PF_INET6,
 145                 .hooknum        = NF_IP6_FORWARD,
 146                 .priority       = NF_IP6_PRI_FILTER,
 147         },
 148         {
 149                 .hook           = ip6t_local_out_hook,
 150                 .owner          = THIS_MODULE,
 151                 .pf             = PF_INET6,
 152                 .hooknum        = NF_IP6_LOCAL_OUT,
 153                 .priority       = NF_IP6_PRI_FILTER,
 154         },
 155 };
 156
 157 /* Default to forward because I got too much mail already. */
 158 static int forward = NF_ACCEPT;
 159 MODULE_PARM(forward, "i");
 160
 161 static int __init init(void)
 162 {
 163         int ret;
 164
 165         if (forward < 0 || forward > NF_MAX_VERDICT) {
 166                 printk("iptables forward must be 0 or 1\n");
 167                 return -EINVAL;
 168         }
 169
 170         /* Entry 1 is the FORWARD hook */
 171         initial_table.entries[1].target.verdict = -forward - 1;
 172
 173         /* Register table */
 174         ret = ip6t_register_table(&packet_filter);
 175         if (ret < 0)
 176                 return ret;
 177
 178         /* Register hooks */
 179         ret = nf_register_hook(&ip6t_ops[0]);
 180         if (ret < 0)
 181                 goto cleanup_table;
 182
 183         ret = nf_register_hook(&ip6t_ops[1]);
 184         if (ret < 0)
 185                 goto cleanup_hook0;
 186
 187         ret = nf_register_hook(&ip6t_ops[2]);
 188         if (ret < 0)
 189                 goto cleanup_hook1;
 190
 191         return ret;
 192
 193  cleanup_hook1:
 194         nf_unregister_hook(&ip6t_ops[1]);
 195  cleanup_hook0:
 196         nf_unregister_hook(&ip6t_ops[0]);
 197  cleanup_table:
 198         ip6t_unregister_table(&packet_filter);
 199
 200         return ret;
 201 }
 202
 203 static void __exit fini(void)
 204 {
 205         unsigned int i;
 206
 207         for (i = 0; i < sizeof(ip6t_ops)/sizeof(struct nf_hook_ops); i++)
 208                 nf_unregister_hook(&ip6t_ops[i]);
 209
 210         ip6t_unregister_table(&packet_filter);
 211 }
 212
 213 module_init(init);
 214 module_exit(fini);