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_IP6_LOCAL_IN) | (1 << NF_IP6_FORWARD) | (1 << NF_IP6_LOCAL_OUT))
  21
  22 /* Standard entry. */
  23 struct ip6t_standard
  24 {
  25         struct ip6t_entry entry;
  26         struct ip6t_standard_target target;
  27 };
  28
  29 struct ip6t_error_target
  30 {
  31         struct ip6t_entry_target target;
  32         char errorname[IP6T_FUNCTION_MAXNAMELEN];
  33 };
  34
  35 struct ip6t_error
  36 {
  37         struct ip6t_entry entry;
  38         struct ip6t_error_target target;
  39 };
  40
  41 static struct
  42 {
  43         struct ip6t_replace repl;
  44         struct ip6t_standard entries[3];
  45         struct ip6t_error term;
  46 } initial_table __initdata
  47 = { { "filter", FILTER_VALID_HOOKS, 4,
  48       sizeof(struct ip6t_standard) * 3 + sizeof(struct ip6t_error),
  49       { [NF_IP6_LOCAL_IN] = 0,
  50         [NF_IP6_FORWARD] = sizeof(struct ip6t_standard),
  51         [NF_IP6_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2 },
  52       { [NF_IP6_LOCAL_IN] = 0,
  53         [NF_IP6_FORWARD] = sizeof(struct ip6t_standard),
  54         [NF_IP6_LOCAL_OUT] = sizeof(struct ip6t_standard) * 2 },
  55       0, NULL, { } },
  56     {
  57             /* LOCAL_IN */
  58             { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },
  59                 0,
  60                 sizeof(struct ip6t_entry),
  61                 sizeof(struct ip6t_standard),
  62                 0, { 0, 0 }, { } },
  63               { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },
  64                 -NF_ACCEPT - 1 } },
  65             /* FORWARD */
  66             { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },
  67                 0,
  68                 sizeof(struct ip6t_entry),
  69                 sizeof(struct ip6t_standard),
  70                 0, { 0, 0 }, { } },
  71               { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },
  72                 -NF_ACCEPT - 1 } },
  73             /* LOCAL_OUT */
  74             { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },
  75                 0,
  76                 sizeof(struct ip6t_entry),
  77                 sizeof(struct ip6t_standard),
  78                 0, { 0, 0 }, { } },
  79               { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },
  80                 -NF_ACCEPT - 1 } }
  81     },
  82     /* ERROR */
  83     { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },
  84         0,
  85         sizeof(struct ip6t_entry),
  86         sizeof(struct ip6t_error),
  87         0, { 0, 0 }, { } },
  88       { { { { IP6T_ALIGN(sizeof(struct ip6t_error_target)), IP6T_ERROR_TARGET } },
  89           { } },
  90         "ERROR"
  91       }
  92     }
  93 };
  94
  95 static struct xt_table packet_filter = {
  96         .name           = "filter",
  97         .valid_hooks    = FILTER_VALID_HOOKS,
  98         .lock           = RW_LOCK_UNLOCKED,
  99         .me             = THIS_MODULE,
 100         .af             = AF_INET6,
 101 };
 102
 103 /* The work comes in here from netfilter.c. */
 104 static unsigned int
 105 ip6t_hook(unsigned int hook,
 106          struct sk_buff **pskb,
 107          const struct net_device *in,
 108          const struct net_device *out,
 109          int (*okfn)(struct sk_buff *))
 110 {
 111         return ip6t_do_table(pskb, hook, in, out, &packet_filter);
 112 }
 113
 114 static unsigned int
 115 ip6t_local_out_hook(unsigned int hook,
 116                    struct sk_buff **pskb,
 117                    const struct net_device *in,
 118                    const struct net_device *out,
 119                    int (*okfn)(struct sk_buff *))
 120 {
 121 #if 0
 122         /* root is playing with raw sockets. */
 123         if ((*pskb)->len < sizeof(struct iphdr)
 124             || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {
 125                 if (net_ratelimit())
 126                         printk("ip6t_hook: happy cracking.\n");
 127                 return NF_ACCEPT;
 128         }
 129 #endif
 130
 131         return ip6t_do_table(pskb, hook, in, out, &packet_filter);
 132 }
 133
 134 static struct nf_hook_ops ip6t_ops[] = {
 135         {
 136                 .hook           = ip6t_hook,
 137                 .owner          = THIS_MODULE,
 138                 .pf             = PF_INET6,
 139                 .hooknum        = NF_IP6_LOCAL_IN,
 140                 .priority       = NF_IP6_PRI_FILTER,
 141         },
 142         {
 143                 .hook           = ip6t_hook,
 144                 .owner          = THIS_MODULE,
 145                 .pf             = PF_INET6,
 146                 .hooknum        = NF_IP6_FORWARD,
 147                 .priority       = NF_IP6_PRI_FILTER,
 148         },
 149         {
 150                 .hook           = ip6t_local_out_hook,
 151                 .owner          = THIS_MODULE,
 152                 .pf             = PF_INET6,
 153                 .hooknum        = NF_IP6_LOCAL_OUT,
 154                 .priority       = NF_IP6_PRI_FILTER,
 155         },
 156 };
 157
 158 /* Default to forward because I got too much mail already. */
 159 static int forward = NF_ACCEPT;
 160 module_param(forward, bool, 0000);
 161
 162 static int __init ip6table_filter_init(void)
 163 {
 164         int ret;
 165
 166         if (forward < 0 || forward > NF_MAX_VERDICT) {
 167                 printk("iptables forward must be 0 or 1\n");
 168                 return -EINVAL;
 169         }
 170
 171         /* Entry 1 is the FORWARD hook */
 172         initial_table.entries[1].target.verdict = -forward - 1;
 173
 174         /* Register table */
 175         ret = ip6t_register_table(&packet_filter, &initial_table.repl);
 176         if (ret < 0)
 177                 return ret;
 178
 179         /* Register hooks */
 180         ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
 181         if (ret < 0)
 182                 goto cleanup_table;
 183
 184         return ret;
 185
 186  cleanup_table:
 187         ip6t_unregister_table(&packet_filter);
 188         return ret;
 189 }
 190
 191 static void __exit ip6table_filter_fini(void)
 192 {
 193         nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
 194         ip6t_unregister_table(&packet_filter);
 195 }
 196
 197 module_init(ip6table_filter_init);
 198 module_exit(ip6table_filter_fini);