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        return PTR_RET(net->ipv4.iptable_raw);
  52}
  53
  54static void __net_exit iptable_raw_net_exit(struct net *net)
  55{
  56        ipt_unregister_table(net, net->ipv4.iptable_raw);
  57}
  58
  59static struct pernet_operations iptable_raw_net_ops = {
  60        .init = iptable_raw_net_init,
  61        .exit = iptable_raw_net_exit,
  62};
  63
  64static int __init iptable_raw_init(void)
  65{
  66        int ret;
  67
  68        ret = register_pernet_subsys(&iptable_raw_net_ops);
  69        if (ret < 0)
  70                return ret;
  71
  72        /* Register hooks */
  73        rawtable_ops = xt_hook_link(&packet_raw, iptable_raw_hook);
  74        if (IS_ERR(rawtable_ops)) {
  75                ret = PTR_ERR(rawtable_ops);
  76                unregister_pernet_subsys(&iptable_raw_net_ops);
  77        }
  78
  79        return ret;
  80}
  81
  82static void __exit iptable_raw_fini(void)
  83{
  84        xt_hook_unlink(&packet_raw, rawtable_ops);
  85        unregister_pernet_subsys(&iptable_raw_net_ops);
  86}
  87
  88module_init(iptable_raw_init);
  89module_exit(iptable_raw_fini);
  90MODULE_LICENSE("GPL");
  91