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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
93557f53 JO |
2 | /* |
3 | * SNMP service broadcast connection tracking helper | |
4 | * | |
5 | * (c) 2011 Jiri Olsa <jolsa@redhat.com> | |
93557f53 JO |
6 | */ |
7 | #include <linux/kernel.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/in.h> | |
11 | ||
12 | #include <net/netfilter/nf_conntrack.h> | |
13 | #include <net/netfilter/nf_conntrack_helper.h> | |
14 | #include <net/netfilter/nf_conntrack_expect.h> | |
5a406b0c | 15 | #include <linux/netfilter/nf_conntrack_snmp.h> |
93557f53 JO |
16 | |
17 | #define SNMP_PORT 161 | |
18 | ||
19 | MODULE_AUTHOR("Jiri Olsa <jolsa@redhat.com>"); | |
20 | MODULE_DESCRIPTION("SNMP service broadcast connection tracking helper"); | |
21 | MODULE_LICENSE("GPL"); | |
22 | MODULE_ALIAS_NFCT_HELPER("snmp"); | |
23 | ||
24 | static unsigned int timeout __read_mostly = 30; | |
d6444062 | 25 | module_param(timeout, uint, 0400); |
93557f53 JO |
26 | MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds"); |
27 | ||
28 | int (*nf_nat_snmp_hook)(struct sk_buff *skb, | |
29 | unsigned int protoff, | |
30 | struct nf_conn *ct, | |
31 | enum ip_conntrack_info ctinfo); | |
32 | EXPORT_SYMBOL_GPL(nf_nat_snmp_hook); | |
33 | ||
34 | static int snmp_conntrack_help(struct sk_buff *skb, unsigned int protoff, | |
433029ec TY |
35 | struct nf_conn *ct, |
36 | enum ip_conntrack_info ctinfo) | |
93557f53 JO |
37 | { |
38 | typeof(nf_nat_snmp_hook) nf_nat_snmp; | |
39 | ||
433029ec | 40 | nf_conntrack_broadcast_help(skb, ct, ctinfo, timeout); |
93557f53 JO |
41 | |
42 | nf_nat_snmp = rcu_dereference(nf_nat_snmp_hook); | |
43 | if (nf_nat_snmp && ct->status & IPS_NAT_MASK) | |
44 | return nf_nat_snmp(skb, protoff, ct, ctinfo); | |
45 | ||
46 | return NF_ACCEPT; | |
47 | } | |
48 | ||
49 | static struct nf_conntrack_expect_policy exp_policy = { | |
50 | .max_expected = 1, | |
51 | }; | |
52 | ||
53 | static struct nf_conntrack_helper helper __read_mostly = { | |
54 | .name = "snmp", | |
55 | .tuple.src.l3num = NFPROTO_IPV4, | |
56 | .tuple.src.u.udp.port = cpu_to_be16(SNMP_PORT), | |
57 | .tuple.dst.protonum = IPPROTO_UDP, | |
58 | .me = THIS_MODULE, | |
59 | .help = snmp_conntrack_help, | |
60 | .expect_policy = &exp_policy, | |
61 | }; | |
62 | ||
63 | static int __init nf_conntrack_snmp_init(void) | |
64 | { | |
65 | exp_policy.timeout = timeout; | |
66 | return nf_conntrack_helper_register(&helper); | |
67 | } | |
68 | ||
69 | static void __exit nf_conntrack_snmp_fini(void) | |
70 | { | |
71 | nf_conntrack_helper_unregister(&helper); | |
72 | } | |
73 | ||
74 | module_init(nf_conntrack_snmp_init); | |
75 | module_exit(nf_conntrack_snmp_fini); |