LXR linux/net/ipv4/netfilter/iptable

   1/*
   2 * 'raw' table, which is the very first hooked in at PRE_ROUTING and LOCAL_OUT .
   3 *
   4 * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
   5 */
   6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7#include <linux/module.h>
   8#include <linux/netfilter_ipv4/ip_tables.h>
   9#include <linux/slab.h>
  10#include <net/ip.h>
  11
  12#define RAW_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT))
  13
  14static int __net_init iptable_raw_table_init(struct net *net);
  15
  16static bool raw_before_defrag __read_mostly;
  17MODULE_PARM_DESC(raw_before_defrag, "Enable raw table before defrag");
  18module_param(raw_before_defrag, bool, 0000);
  19
  20static const struct xt_table packet_raw = {
  21        .name = "raw",
  22        .valid_hooks =  RAW_VALID_HOOKS,
  23        .me = THIS_MODULE,
  24        .af = NFPROTO_IPV4,
  25        .priority = NF_IP_PRI_RAW,
  26        .table_init = iptable_raw_table_init,
  27};
  28
  29static const struct xt_table packet_raw_before_defrag = {
  30        .name = "raw",
  31        .valid_hooks =  RAW_VALID_HOOKS,
  32        .me = THIS_MODULE,
  33        .af = NFPROTO_IPV4,
  34        .priority = NF_IP_PRI_RAW_BEFORE_DEFRAG,
  35        .table_init = iptable_raw_table_init,
  36};
  37
  38/* The work comes in here from netfilter.c. */
  39static unsigned int
  40iptable_raw_hook(void *priv, struct sk_buff *skb,
  41                 const struct nf_hook_state *state)
  42{
  43        return ipt_do_table(skb, state, state->net->ipv4.iptable_raw);
  44}
  45
  46static struct nf_hook_ops *rawtable_ops __read_mostly;
  47
  48static int __net_init iptable_raw_table_init(struct net *net)
  49{
  50        struct ipt_replace *repl;
  51        const struct xt_table *table = &packet_raw;
  52        int ret;
  53
  54        if (raw_before_defrag)
  55                table = &packet_raw_before_defrag;
  56
  57        if (net->ipv4.iptable_raw)
  58                return 0;
  59
  60        repl = ipt_alloc_initial_table(table);
  61        if (repl == NULL)
  62                return -ENOMEM;
  63        ret = ipt_register_table(net, table, repl, rawtable_ops,
  64                                 &net->ipv4.iptable_raw);
  65        kfree(repl);
  66        return ret;
  67}
  68
  69static void __net_exit iptable_raw_net_pre_exit(struct net *net)
  70{
  71        if (net->ipv4.iptable_raw)
  72                ipt_unregister_table_pre_exit(net, net->ipv4.iptable_raw,
  73                                              rawtable_ops);
  74}
  75
  76static void __net_exit iptable_raw_net_exit(struct net *net)
  77{
  78        if (!net->ipv4.iptable_raw)
  79                return;
  80        ipt_unregister_table_exit(net, net->ipv4.iptable_raw);
  81        net->ipv4.iptable_raw = NULL;
  82}
  83
  84static struct pernet_operations iptable_raw_net_ops = {
  85        .pre_exit = iptable_raw_net_pre_exit,
  86        .exit = iptable_raw_net_exit,
  87};
  88
  89static int __init iptable_raw_init(void)
  90{
  91        int ret;
  92        const struct xt_table *table = &packet_raw;
  93
  94        if (raw_before_defrag) {
  95                table = &packet_raw_before_defrag;
  96
  97                pr_info("Enabling raw table before defrag\n");
  98        }
  99
 100        rawtable_ops = xt_hook_ops_alloc(table, iptable_raw_hook);
 101        if (IS_ERR(rawtable_ops))
 102                return PTR_ERR(rawtable_ops);
 103
 104        ret = register_pernet_subsys(&iptable_raw_net_ops);
 105        if (ret < 0) {
 106                kfree(rawtable_ops);
 107                return ret;
 108        }
 109
 110        ret = iptable_raw_table_init(&init_net);
 111        if (ret) {
 112                unregister_pernet_subsys(&iptable_raw_net_ops);
 113                kfree(rawtable_ops);
 114        }
 115
 116        return ret;
 117}
 118
 119static void __exit iptable_raw_fini(void)
 120{
 121        unregister_pernet_subsys(&iptable_raw_net_ops);
 122        kfree(rawtable_ops);
 123}
 124
 125module_init(iptable_raw_init);
 126module_exit(iptable_raw_fini);
 127MODULE_LICENSE("GPL");
 128