]>
Commit | Line | Data |
---|---|---|
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> | |
21 | #include <linux/skbuff.h> | |
22 | #include <linux/netdevice.h> | |
23 | #include <linux/inetdevice.h> | |
24 | #include <linux/if_addr.h> | |
25 | #include <linux/in.h> | |
26 | #include <linux/ip.h> | |
1863f096 | 27 | #include <linux/netfilter.h> |
92703eee PM |
28 | #include <net/route.h> |
29 | ||
30 | #include <net/netfilter/nf_conntrack.h> | |
31 | #include <net/netfilter/nf_conntrack_helper.h> | |
32 | #include <net/netfilter/nf_conntrack_expect.h> | |
33 | ||
34 | #define NMBD_PORT 137 | |
35 | ||
36 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
37 | MODULE_DESCRIPTION("NetBIOS name service broadcast connection tracking helper"); | |
38 | MODULE_LICENSE("GPL"); | |
39 | MODULE_ALIAS("ip_conntrack_netbios_ns"); | |
4dc06f96 | 40 | MODULE_ALIAS_NFCT_HELPER("netbios_ns"); |
92703eee PM |
41 | |
42 | static unsigned int timeout __read_mostly = 3; | |
43 | module_param(timeout, uint, 0400); | |
44 | MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds"); | |
45 | ||
3db05fea | 46 | static int help(struct sk_buff *skb, unsigned int protoff, |
601e68e1 | 47 | struct nf_conn *ct, enum ip_conntrack_info ctinfo) |
92703eee PM |
48 | { |
49 | struct nf_conntrack_expect *exp; | |
3db05fea | 50 | struct iphdr *iph = ip_hdr(skb); |
ee6b9673 | 51 | struct rtable *rt = skb->rtable; |
92703eee PM |
52 | struct in_device *in_dev; |
53 | __be32 mask = 0; | |
54 | ||
55 | /* we're only interested in locally generated packets */ | |
3db05fea | 56 | if (skb->sk == NULL) |
92703eee PM |
57 | goto out; |
58 | if (rt == NULL || !(rt->rt_flags & RTCF_BROADCAST)) | |
59 | goto out; | |
60 | if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) | |
61 | goto out; | |
62 | ||
63 | rcu_read_lock(); | |
64 | in_dev = __in_dev_get_rcu(rt->u.dst.dev); | |
65 | if (in_dev != NULL) { | |
66 | for_primary_ifa(in_dev) { | |
67 | if (ifa->ifa_broadcast == iph->daddr) { | |
68 | mask = ifa->ifa_mask; | |
69 | break; | |
70 | } | |
71 | } endfor_ifa(in_dev); | |
72 | } | |
73 | rcu_read_unlock(); | |
74 | ||
75 | if (mask == 0) | |
76 | goto out; | |
77 | ||
6823645d | 78 | exp = nf_ct_expect_alloc(ct); |
92703eee PM |
79 | if (exp == NULL) |
80 | goto out; | |
81 | ||
82 | exp->tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple; | |
83 | exp->tuple.src.u.udp.port = htons(NMBD_PORT); | |
84 | ||
85 | exp->mask.src.u3.ip = mask; | |
86 | exp->mask.src.u.udp.port = htons(0xFFFF); | |
92703eee PM |
87 | |
88 | exp->expectfn = NULL; | |
89 | exp->flags = NF_CT_EXPECT_PERMANENT; | |
6002f266 | 90 | exp->class = NF_CT_EXPECT_CLASS_DEFAULT; |
88044c8c | 91 | exp->helper = NULL; |
92703eee | 92 | |
6823645d PM |
93 | nf_ct_expect_related(exp); |
94 | nf_ct_expect_put(exp); | |
92703eee | 95 | |
3db05fea | 96 | nf_ct_refresh(ct, skb, timeout * HZ); |
92703eee PM |
97 | out: |
98 | return NF_ACCEPT; | |
99 | } | |
100 | ||
6002f266 PM |
101 | static struct nf_conntrack_expect_policy exp_policy = { |
102 | .max_expected = 1, | |
103 | }; | |
104 | ||
92703eee PM |
105 | static struct nf_conntrack_helper helper __read_mostly = { |
106 | .name = "netbios-ns", | |
107 | .tuple.src.l3num = AF_INET, | |
108 | .tuple.src.u.udp.port = __constant_htons(NMBD_PORT), | |
109 | .tuple.dst.protonum = IPPROTO_UDP, | |
92703eee PM |
110 | .me = THIS_MODULE, |
111 | .help = help, | |
6002f266 | 112 | .expect_policy = &exp_policy, |
92703eee PM |
113 | }; |
114 | ||
115 | static int __init nf_conntrack_netbios_ns_init(void) | |
116 | { | |
6002f266 | 117 | exp_policy.timeout = timeout; |
92703eee PM |
118 | return nf_conntrack_helper_register(&helper); |
119 | } | |
120 | ||
121 | static void __exit nf_conntrack_netbios_ns_fini(void) | |
122 | { | |
123 | nf_conntrack_helper_unregister(&helper); | |
124 | } | |
125 | ||
126 | module_init(nf_conntrack_netbios_ns_init); | |
127 | module_exit(nf_conntrack_netbios_ns_fini); |