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114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
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/* iptables module to match on related connections */
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/*
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* (C) 2001 Martin Josefsson <gandalf@wlug.westbo.se>
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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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* 19 Mar 2002 Harald Welte <laforge@gnumonks.org>:
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* - Port to newnat infrastructure
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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.h>
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#include <linux/netfilter_ipv4/ip_conntrack.h>
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#include <linux/netfilter_ipv4/ip_conntrack_core.h>
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#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ipt_helper.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>");
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MODULE_DESCRIPTION("iptables helper match module");
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#if 0
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#define DEBUGP printk
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#else
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#define DEBUGP(format, args...)
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#endif
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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_helper_info *info = matchinfo;
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struct ip_conntrack *ct;
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enum ip_conntrack_info ctinfo;
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int ret = info->invert;
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ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo);
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if (!ct) {
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DEBUGP("ipt_helper: Eek! invalid conntrack?\n");
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return ret;
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}
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if (!ct->master) {
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DEBUGP("ipt_helper: conntrack %p has no master\n", ct);
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return ret;
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}
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READ_LOCK(&ip_conntrack_lock);
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if (!ct->master->helper) {
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DEBUGP("ipt_helper: master ct %p has no helper\n",
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exp->expectant);
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goto out_unlock;
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}
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DEBUGP("master's name = %s , info->name = %s\n",
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ct->master->helper->name, info->name);
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if (info->name[0] == '\0')
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ret ^= 1;
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else
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ret ^= !strncmp(ct->master->helper->name, info->name,
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strlen(ct->master->helper->name));
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out_unlock:
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READ_UNLOCK(&ip_conntrack_lock);
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return ret;
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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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struct ipt_helper_info *info = matchinfo;
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info->name[29] = '\0';
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/* verify size */
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if (matchsize != IPT_ALIGN(sizeof(struct ipt_helper_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 helper_match = {
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.name = "helper",
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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(&helper_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(&helper_match);
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}
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module_init(init);
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module_exit(fini);
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