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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
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2 | /* |
3 | * NetBIOS name service broadcast connection tracking helper | |
4 | * | |
5 | * (c) 2005 Patrick McHardy <kaber@trash.net> | |
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6 | */ |
7 | /* | |
8 | * This helper tracks locally originating NetBIOS name service | |
9 | * requests by issuing permanent expectations (valid until | |
10 | * timing out) matching all reply connections from the | |
11 | * destination network. The only NetBIOS specific thing is | |
12 | * actually the port number. | |
13 | */ | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/init.h> | |
92703eee | 17 | #include <linux/in.h> |
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18 | |
19 | #include <net/netfilter/nf_conntrack.h> | |
20 | #include <net/netfilter/nf_conntrack_helper.h> | |
21 | #include <net/netfilter/nf_conntrack_expect.h> | |
22 | ||
0e906607 | 23 | #define HELPER_NAME "netbios-ns" |
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24 | #define NMBD_PORT 137 |
25 | ||
26 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
27 | MODULE_DESCRIPTION("NetBIOS name service broadcast connection tracking helper"); | |
28 | MODULE_LICENSE("GPL"); | |
29 | MODULE_ALIAS("ip_conntrack_netbios_ns"); | |
0e906607 | 30 | MODULE_ALIAS_NFCT_HELPER(HELPER_NAME); |
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31 | |
32 | static unsigned int timeout __read_mostly = 3; | |
d6444062 | 33 | module_param(timeout, uint, 0400); |
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34 | MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds"); |
35 | ||
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36 | static struct nf_conntrack_expect_policy exp_policy = { |
37 | .max_expected = 1, | |
38 | }; | |
39 | ||
93557f53 | 40 | static int netbios_ns_help(struct sk_buff *skb, unsigned int protoff, |
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41 | struct nf_conn *ct, |
42 | enum ip_conntrack_info ctinfo) | |
93557f53 | 43 | { |
433029ec | 44 | return nf_conntrack_broadcast_help(skb, ct, ctinfo, timeout); |
93557f53 JO |
45 | } |
46 | ||
92703eee | 47 | static struct nf_conntrack_helper helper __read_mostly = { |
0e906607 | 48 | .name = HELPER_NAME, |
93557f53 | 49 | .tuple.src.l3num = NFPROTO_IPV4, |
09640e63 | 50 | .tuple.src.u.udp.port = cpu_to_be16(NMBD_PORT), |
92703eee | 51 | .tuple.dst.protonum = IPPROTO_UDP, |
92703eee | 52 | .me = THIS_MODULE, |
93557f53 | 53 | .help = netbios_ns_help, |
6002f266 | 54 | .expect_policy = &exp_policy, |
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55 | }; |
56 | ||
57 | static int __init nf_conntrack_netbios_ns_init(void) | |
58 | { | |
dcf67740 FW |
59 | NF_CT_HELPER_BUILD_BUG_ON(0); |
60 | ||
6002f266 | 61 | exp_policy.timeout = timeout; |
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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); |