94 lines
2.5 KiB
C
94 lines
2.5 KiB
C
/* Kernel module to match connection tracking information. */
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/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2005 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 <net/netfilter/nf_conntrack.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_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("ip[6]_tables connection tracking state match module");
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MODULE_ALIAS("ipt_state");
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MODULE_ALIAS("ip6t_state");
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static bool
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state_mt(const struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, const struct xt_match *match,
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const void *matchinfo, int offset, unsigned int protoff,
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bool *hotdrop)
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{
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const struct xt_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 (nf_ct_is_untracked(skb))
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statebit = XT_STATE_UNTRACKED;
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else if (!nf_ct_get(skb, &ctinfo))
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statebit = XT_STATE_INVALID;
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else
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statebit = XT_STATE_BIT(ctinfo);
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return (sinfo->statemask & statebit);
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}
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static bool
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state_mt_check(const char *tablename, const void *inf,
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const struct xt_match *match, void *matchinfo,
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unsigned int hook_mask)
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{
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if (nf_ct_l3proto_try_module_get(match->family) < 0) {
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printk(KERN_WARNING "can't load conntrack support for "
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"proto=%u\n", match->family);
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return false;
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}
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return true;
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}
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static void state_mt_destroy(const struct xt_match *match, void *matchinfo)
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{
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nf_ct_l3proto_module_put(match->family);
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}
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static struct xt_match state_mt_reg[] __read_mostly = {
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{
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.name = "state",
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.family = AF_INET,
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.checkentry = state_mt_check,
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.match = state_mt,
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.destroy = state_mt_destroy,
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.matchsize = sizeof(struct xt_state_info),
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.me = THIS_MODULE,
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},
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{
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.name = "state",
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.family = AF_INET6,
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.checkentry = state_mt_check,
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.match = state_mt,
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.destroy = state_mt_destroy,
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.matchsize = sizeof(struct xt_state_info),
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.me = THIS_MODULE,
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},
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};
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static int __init state_mt_init(void)
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{
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return xt_register_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
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}
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static void __exit state_mt_exit(void)
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{
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xt_unregister_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
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}
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module_init(state_mt_init);
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module_exit(state_mt_exit);
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