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92703eee PM |
1 | /* |
2 | * NetBIOS name service broadcast connection tracking helper | |
3 | * | |
4 | * (c) 2005 Patrick McHardy <kaber@trash.net> | |
5 | * | |
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. | |
10 | */ | |
11 | /* | |
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. | |
17 | */ | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/init.h> | |
92703eee | 21 | #include <linux/in.h> |
92703eee PM |
22 | |
23 | #include <net/netfilter/nf_conntrack.h> | |
24 | #include <net/netfilter/nf_conntrack_helper.h> | |
25 | #include <net/netfilter/nf_conntrack_expect.h> | |
26 | ||
27 | #define NMBD_PORT 137 | |
28 | ||
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"); | |
4dc06f96 | 33 | MODULE_ALIAS_NFCT_HELPER("netbios_ns"); |
92703eee PM |
34 | |
35 | static unsigned int timeout __read_mostly = 3; | |
93557f53 | 36 | module_param(timeout, uint, S_IRUSR); |
92703eee PM |
37 | MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds"); |
38 | ||
6002f266 PM |
39 | static struct nf_conntrack_expect_policy exp_policy = { |
40 | .max_expected = 1, | |
41 | }; | |
42 | ||
93557f53 JO |
43 | static int netbios_ns_help(struct sk_buff *skb, unsigned int protoff, |
44 | struct nf_conn *ct, enum ip_conntrack_info ctinfo) | |
45 | { | |
46 | return nf_conntrack_broadcast_help(skb, protoff, ct, ctinfo, timeout); | |
47 | } | |
48 | ||
92703eee PM |
49 | static struct nf_conntrack_helper helper __read_mostly = { |
50 | .name = "netbios-ns", | |
93557f53 | 51 | .tuple.src.l3num = NFPROTO_IPV4, |
09640e63 | 52 | .tuple.src.u.udp.port = cpu_to_be16(NMBD_PORT), |
92703eee | 53 | .tuple.dst.protonum = IPPROTO_UDP, |
92703eee | 54 | .me = THIS_MODULE, |
93557f53 | 55 | .help = netbios_ns_help, |
6002f266 | 56 | .expect_policy = &exp_policy, |
92703eee PM |
57 | }; |
58 | ||
59 | static int __init nf_conntrack_netbios_ns_init(void) | |
60 | { | |
6002f266 | 61 | exp_policy.timeout = timeout; |
92703eee PM |
62 | return nf_conntrack_helper_register(&helper); |
63 | } | |
64 | ||
65 | static void __exit nf_conntrack_netbios_ns_fini(void) | |
66 | { | |
67 | nf_conntrack_helper_unregister(&helper); | |
68 | } | |
69 | ||
70 | module_init(nf_conntrack_netbios_ns_init); | |
71 | module_exit(nf_conntrack_netbios_ns_fini); |