Eric Lee / smarc-fsl-linux-kernel

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net/netfilter/nf_conntrack_snmp.c 2 KB
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2874c5fd2   Thomas Gleixner   treewide: Replace... 
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  // SPDX-License-Identifier: GPL-2.0-or-later
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  /*
   *      SNMP service broadcast connection tracking helper
   *
   *      (c) 2011 Jiri Olsa <jolsa@redhat.com>
93557f53e   Jiri Olsa   netfilter: nf_con... 
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   */
  #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>
5a406b0cd   stephen hemminger   netfilter: nf_ct_... 
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  #include <linux/netfilter/nf_conntrack_snmp.h>
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  #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;
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  module_param(timeout, uint, 0400);
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  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,
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  			       struct nf_conn *ct,
  			       enum ip_conntrack_info ctinfo)
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  {
  	typeof(nf_nat_snmp_hook) nf_nat_snmp;
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  	nf_conntrack_broadcast_help(skb, ct, ctinfo, timeout);
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  	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);