75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
/* Kernel module to match connection tracking information. */
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/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter_ipv4/ip_conntrack.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ipt_state.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
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MODULE_DESCRIPTION("iptables connection tracking state match module");
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static int
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match(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const void *matchinfo,
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int offset,
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int *hotdrop)
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{
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const struct ipt_state_info *sinfo = matchinfo;
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enum ip_conntrack_info ctinfo;
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unsigned int statebit;
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if (skb->nfct == &ip_conntrack_untracked.ct_general)
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statebit = IPT_STATE_UNTRACKED;
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else if (!ip_conntrack_get(skb, &ctinfo))
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statebit = IPT_STATE_INVALID;
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else
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statebit = IPT_STATE_BIT(ctinfo);
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return (sinfo->statemask & statebit);
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}
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static int check(const char *tablename,
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const struct ipt_ip *ip,
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void *matchinfo,
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unsigned int matchsize,
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unsigned int hook_mask)
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{
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if (matchsize != IPT_ALIGN(sizeof(struct ipt_state_info)))
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return 0;
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return 1;
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}
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static struct ipt_match state_match = {
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.name = "state",
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.match = &match,
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.checkentry = &check,
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.me = THIS_MODULE,
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};
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static int __init init(void)
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{
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need_ip_conntrack();
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return ipt_register_match(&state_match);
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}
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static void __exit fini(void)
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{
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ipt_unregister_match(&state_match);
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}
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module_init(init);
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module_exit(fini);
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