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#include <linux/module.h>
   7#include <linux/netfilter_ipv4/ip_tables.h>
   8#include <linux/slab.h>
   9#include <net/ip.h>
  10
  11#define RAW_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT))
  12
  13static int __net_init iptable_raw_table_init(struct net *net);
  14
  15static const struct xt_table packet_raw = {
  16        .name = "raw",
  17        .valid_hooks =  RAW_VALID_HOOKS,
  18        .me = THIS_MODULE,
  19        .af = NFPROTO_IPV4,
  20        .priority = NF_IP_PRI_RAW,
  21        .table_init = iptable_raw_table_init,
  22};
  23
  24/* The work comes in here from netfilter.c. */
  25static unsigned int
  26iptable_raw_hook(void *priv, struct sk_buff *skb,
  27                 const struct nf_hook_state *state)
  28{
  29        if (state->hook == NF_INET_LOCAL_OUT &&
  30            (skb->len < sizeof(struct iphdr) ||
  31             ip_hdrlen(skb) < sizeof(struct iphdr)))
  32                /* root is playing with raw sockets. */
  33                return NF_ACCEPT;
  34
  35        return ipt_do_table(skb, state, state->net->ipv4.iptable_raw);
  36}
  37
  38static struct nf_hook_ops *rawtable_ops __read_mostly;
  39
  40static int __net_init iptable_raw_table_init(struct net *net)
  41{
  42        struct ipt_replace *repl;
  43        int ret;
  44
  45        if (net->ipv4.iptable_raw)
  46                return 0;
  47
  48        repl = ipt_alloc_initial_table(&packet_raw);
  49        if (repl == NULL)
  50                return -ENOMEM;
  51        ret = ipt_register_table(net, &packet_raw, repl, rawtable_ops,
  52                                 &net->ipv4.iptable_raw);
  53        kfree(repl);
  54        return ret;
  55}
  56
  57static void __net_exit iptable_raw_net_exit(struct net *net)
  58{
  59        if (!net->ipv4.iptable_raw)
  60                return;
  61        ipt_unregister_table(net, net->ipv4.iptable_raw, rawtable_ops);
  62        net->ipv4.iptable_raw = NULL;
  63}
  64
  65static struct pernet_operations iptable_raw_net_ops = {
  66        .exit = iptable_raw_net_exit,
  67};
  68
  69static int __init iptable_raw_init(void)
  70{
  71        int ret;
  72
  73        rawtable_ops = xt_hook_ops_alloc(&packet_raw, iptable_raw_hook);
  74        if (IS_ERR(rawtable_ops))
  75                return PTR_ERR(rawtable_ops);
  76
  77        ret = register_pernet_subsys(&iptable_raw_net_ops);
  78        if (ret < 0) {
  79                kfree(rawtable_ops);
  80                return ret;
  81        }
  82
  83        ret = iptable_raw_table_init(&init_net);
  84        if (ret) {
  85                unregister_pernet_subsys(&iptable_raw_net_ops);
  86                kfree(rawtable_ops);
  87        }
  88
  89        return ret;
  90}
  91
  92static void __exit iptable_raw_fini(void)
  93{
  94        unregister_pernet_subsys(&iptable_raw_net_ops);
  95        kfree(rawtable_ops);
  96}
  97
  98module_init(iptable_raw_init);
  99module_exit(iptable_raw_fini);
 100MODULE_LICENSE("GPL");
 101