0ecec701cb448dc23224182aec2489ddf43f9e49
[linux-2.6.git] / net / ipv4 / netfilter / nf_nat_tftp.c
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
18 MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
19 MODULE_DESCRIPTION("TFTP NAT helper");
20 MODULE_LICENSE("GPL");
21 MODULE_ALIAS("ip_nat_tftp");
22
23 static unsigned int help(struct sk_buff *skb,
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_ct_expect_related(exp) != 0)
34                 return NF_DROP;
35         return NF_ACCEPT;
36 }
37
38 static void __exit nf_nat_tftp_fini(void)
39 {
40         rcu_assign_pointer(nf_nat_tftp_hook, NULL);
41         synchronize_rcu();
42 }
43
44 static 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
51 module_init(nf_nat_tftp_init);
52 module_exit(nf_nat_tftp_fini);