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 **pskb,
24			 enum ip_conntrack_info ctinfo,
25			 struct nf_conntrack_expect *exp)
26{
27	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_conntrack_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(rcu_dereference(nf_nat_tftp_hook));
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