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 const struct xt_table packet_raw = {
  14        .name = "raw",
  15        .valid_hooks =  RAW_VALID_HOOKS,
  16        .me = THIS_MODULE,
  17        .af = NFPROTO_IPV4,
  18        .priority = NF_IP_PRI_RAW,
  19};
  20
  21/* The work comes in here from netfilter.c. */
  22static unsigned int
  23iptable_raw_hook(unsigned int hook, struct sk_buff *skb,
  24                 const struct net_device *in, const struct net_device *out,
  25                 int (*okfn)(struct sk_buff *))
  26{
  27        const struct net *net;
  28
  29        if (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        net = dev_net((in != NULL) ? in : out);
  36        return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_raw);
  37}
  38
  39static struct nf_hook_ops *rawtable_ops __read_mostly;
  40
  41static int __net_init iptable_raw_net_init(struct net *net)
  42{
  43        struct ipt_replace *repl;
  44
  45        repl = ipt_alloc_initial_table(&packet_raw);
  46        if (repl == NULL)
  47                return -ENOMEM;
  48        net->ipv4.iptable_raw =
  49                ipt_register_table(net, &packet_raw, repl);
  50        kfree(repl);
  51        if (IS_ERR(net->ipv4.iptable_raw))
  52                return PTR_ERR(net->ipv4.iptable_raw);
  53        return 0;
  54}
  55
  56static void __net_exit iptable_raw_net_exit(struct net *net)
  57{
  58        ipt_unregister_table(net, net->ipv4.iptable_raw);
  59}
  60
  61static struct pernet_operations iptable_raw_net_ops = {
  62        .init = iptable_raw_net_init,
  63        .exit = iptable_raw_net_exit,
  64};
  65
  66static int __init iptable_raw_init(void)
  67{
  68        int ret;
  69
  70        ret = register_pernet_subsys(&iptable_raw_net_ops);
  71        if (ret < 0)
  72                return ret;
  73
  74        /* Register hooks */
  75        rawtable_ops = xt_hook_link(&packet_raw, iptable_raw_hook);
  76        if (IS_ERR(rawtable_ops)) {
  77                ret = PTR_ERR(rawtable_ops);
  78                goto cleanup_table;
  79        }
  80
  81        return ret;
  82
  83 cleanup_table:
  84        unregister_pernet_subsys(&iptable_raw_net_ops);
  85        return ret;
  86}
  87
  88static void __exit iptable_raw_fini(void)
  89{
  90        xt_hook_unlink(&packet_raw, rawtable_ops);
  91        unregister_pernet_subsys(&iptable_raw_net_ops);
  92}
  93
  94module_init(iptable_raw_init);
  95module_exit(iptable_raw_fini);
  96MODULE_LICENSE("GPL");
  97