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		nf_ct_helper_log(skb, exp->master, "cannot add expectation");
33		return NF_DROP;
34	}
35	return NF_ACCEPT;
36}
37
38static void __exit nf_nat_tftp_fini(void)
39{
40	RCU_INIT_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_INIT_POINTER(nf_nat_tftp_hook, help);
48	return 0;
49}
50
51module_init(nf_nat_tftp_init);
52module_exit(nf_nat_tftp_fini);
53