LXR linux/net/ipv4/netfilter/nf_nat

   1/* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
   2 *
   3 * This program is free software; you can redistribute it and/or modify
   4 * it under the terms of the GNU General Public License version 2 as
   5 * published by the Free Software Foundation.
   6 */
   7
   8#include <linux/module.h>
   9#include <linux/udp.h>
  10
  11#include <net/netfilter/nf_nat_helper.h>
  12#include <net/netfilter/nf_nat_rule.h>
  13#include <net/netfilter/nf_conntrack_helper.h>
  14#include <net/netfilter/nf_conntrack_expect.h>
  15#include <linux/netfilter/nf_conntrack_tftp.h>
  16
  17MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
  18MODULE_DESCRIPTION("TFTP NAT helper");
  19MODULE_LICENSE("GPL");
  20MODULE_ALIAS("ip_nat_tftp");
  21
  22static unsigned int help(struct sk_buff *skb,
  23                         enum ip_conntrack_info ctinfo,
  24                         struct nf_conntrack_expect *exp)
  25{
  26        const struct nf_conn *ct = exp->master;
  27
  28        exp->saved_proto.udp.port
  29                = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
  30        exp->dir = IP_CT_DIR_REPLY;
  31        exp->expectfn = nf_nat_follow_master;
  32        if (nf_ct_expect_related(exp) != 0)
  33                return NF_DROP;
  34        return NF_ACCEPT;
  35}
  36
  37static void __exit nf_nat_tftp_fini(void)
  38{
  39        rcu_assign_pointer(nf_nat_tftp_hook, NULL);
  40        synchronize_rcu();
  41}
  42
  43static int __init nf_nat_tftp_init(void)
  44{
  45        BUG_ON(nf_nat_tftp_hook != NULL);
  46        rcu_assign_pointer(nf_nat_tftp_hook, help);
  47        return 0;
  48}
  49
  50module_init(nf_nat_tftp_init);
  51module_exit(nf_nat_tftp_fini);
  52