2 * NetBIOS name service broadcast connection tracking helper
4 * (c) 2005 Patrick McHardy <kaber@trash.net>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 * This helper tracks locally originating NetBIOS name service
13 * requests by issuing permanent expectations (valid until
14 * timing out) matching all reply connections from the
15 * destination network. The only NetBIOS specific thing is
16 * actually the port number.
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
23 #include <net/netfilter/nf_conntrack.h>
24 #include <net/netfilter/nf_conntrack_helper.h>
25 #include <net/netfilter/nf_conntrack_expect.h>
29 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
30 MODULE_DESCRIPTION("NetBIOS name service broadcast connection tracking helper");
31 MODULE_LICENSE("GPL");
32 MODULE_ALIAS("ip_conntrack_netbios_ns");
33 MODULE_ALIAS_NFCT_HELPER("netbios_ns");
35 static unsigned int timeout __read_mostly = 3;
36 module_param(timeout, uint, 0400);
37 MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds");
39 static struct nf_conntrack_expect_policy exp_policy = {
43 static int netbios_ns_help(struct sk_buff *skb, unsigned int protoff,
45 enum ip_conntrack_info ctinfo)
47 return nf_conntrack_broadcast_help(skb, ct, ctinfo, timeout);
50 static struct nf_conntrack_helper helper __read_mostly = {
52 .tuple.src.l3num = NFPROTO_IPV4,
53 .tuple.src.u.udp.port = cpu_to_be16(NMBD_PORT),
54 .tuple.dst.protonum = IPPROTO_UDP,
56 .help = netbios_ns_help,
57 .expect_policy = &exp_policy,
60 static int __init nf_conntrack_netbios_ns_init(void)
62 NF_CT_HELPER_BUILD_BUG_ON(0);
64 exp_policy.timeout = timeout;
65 return nf_conntrack_helper_register(&helper);
68 static void __exit nf_conntrack_netbios_ns_fini(void)
70 nf_conntrack_helper_unregister(&helper);
73 module_init(nf_conntrack_netbios_ns_init);
74 module_exit(nf_conntrack_netbios_ns_fini);