123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778 |
- /*
- * SNMP service broadcast connection tracking helper
- *
- * (c) 2011 Jiri Olsa <jolsa@redhat.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/init.h>
- #include <linux/in.h>
- #include <net/netfilter/nf_conntrack.h>
- #include <net/netfilter/nf_conntrack_helper.h>
- #include <net/netfilter/nf_conntrack_expect.h>
- #include <linux/netfilter/nf_conntrack_snmp.h>
- #define SNMP_PORT 161
- MODULE_AUTHOR("Jiri Olsa <jolsa@redhat.com>");
- MODULE_DESCRIPTION("SNMP service broadcast connection tracking helper");
- MODULE_LICENSE("GPL");
- MODULE_ALIAS_NFCT_HELPER("snmp");
- static unsigned int timeout __read_mostly = 30;
- module_param(timeout, uint, S_IRUSR);
- MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds");
- int (*nf_nat_snmp_hook)(struct sk_buff *skb,
- unsigned int protoff,
- struct nf_conn *ct,
- enum ip_conntrack_info ctinfo);
- EXPORT_SYMBOL_GPL(nf_nat_snmp_hook);
- static int snmp_conntrack_help(struct sk_buff *skb, unsigned int protoff,
- struct nf_conn *ct, enum ip_conntrack_info ctinfo)
- {
- typeof(nf_nat_snmp_hook) nf_nat_snmp;
- nf_conntrack_broadcast_help(skb, protoff, ct, ctinfo, timeout);
- nf_nat_snmp = rcu_dereference(nf_nat_snmp_hook);
- if (nf_nat_snmp && ct->status & IPS_NAT_MASK)
- return nf_nat_snmp(skb, protoff, ct, ctinfo);
- return NF_ACCEPT;
- }
- static struct nf_conntrack_expect_policy exp_policy = {
- .max_expected = 1,
- };
- static struct nf_conntrack_helper helper __read_mostly = {
- .name = "snmp",
- .tuple.src.l3num = NFPROTO_IPV4,
- .tuple.src.u.udp.port = cpu_to_be16(SNMP_PORT),
- .tuple.dst.protonum = IPPROTO_UDP,
- .me = THIS_MODULE,
- .help = snmp_conntrack_help,
- .expect_policy = &exp_policy,
- };
- static int __init nf_conntrack_snmp_init(void)
- {
- exp_policy.timeout = timeout;
- return nf_conntrack_helper_register(&helper);
- }
- static void __exit nf_conntrack_snmp_fini(void)
- {
- nf_conntrack_helper_unregister(&helper);
- }
- module_init(nf_conntrack_snmp_init);
- module_exit(nf_conntrack_snmp_fini);
|