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