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/moduleparam.h>
  10#include <linux/udp.h>
  11
  12#include <net/netfilter/nf_nat_helper.h>
  13#include <net/netfilter/nf_nat_rule.h>
  14#include <net/netfilter/nf_conntrack_helper.h>
  15#include <net/netfilter/nf_conntrack_expect.h>
  16#include <linux/netfilter/nf_conntrack_tftp.h>
  17
  18MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
  19MODULE_DESCRIPTION("TFTP NAT helper");
  20MODULE_LICENSE("GPL");
  21MODULE_ALIAS("ip_nat_tftp");
  22
  23static unsigned int help(struct sk_buff *skb,
  24                         enum ip_conntrack_info ctinfo,
  25                         struct nf_conntrack_expect *exp)
  26{
  27        const struct nf_conn *ct = exp->master;
  28
  29        exp->saved_proto.udp.port
  30                = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
  31        exp->dir = IP_CT_DIR_REPLY;
  32        exp->expectfn = nf_nat_follow_master;
  33        if (nf_ct_expect_related(exp) != 0)
  34                return NF_DROP;
  35        return NF_ACCEPT;
  36}
  37
  38static void __exit nf_nat_tftp_fini(void)
  39{
  40        rcu_assign_pointer(nf_nat_tftp_hook, NULL);
  41        synchronize_rcu();
  42}
  43
  44static int __init nf_nat_tftp_init(void)
  45{
  46        BUG_ON(nf_nat_tftp_hook != NULL);
  47        rcu_assign_pointer(nf_nat_tftp_hook, help);
  48        return 0;
  49}
  50
  51module_init(nf_nat_tftp_init);
  52module_exit(nf_nat_tftp_fini);
  53