Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
137 lines
3.2 KiB
C
137 lines
3.2 KiB
C
/* 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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#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 <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_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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MODULE_ALIAS("ipt_helper");
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MODULE_ALIAS("ip6t_helper");
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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 struct xt_match *match,
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const void *matchinfo,
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int offset,
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unsigned int protoff,
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int *hotdrop)
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{
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const struct xt_helper_info *info = matchinfo;
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struct nf_conn *ct;
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struct nf_conn_help *master_help;
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enum ip_conntrack_info ctinfo;
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int ret = info->invert;
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ct = nf_ct_get((struct sk_buff *)skb, &ctinfo);
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if (!ct) {
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DEBUGP("xt_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("xt_helper: conntrack %p has no master\n", ct);
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return ret;
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}
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read_lock_bh(&nf_conntrack_lock);
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master_help = nfct_help(ct->master);
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if (!master_help || !master_help->helper) {
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DEBUGP("xt_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(master_help->helper->name, info->name,
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strlen(master_help->helper->name));
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out_unlock:
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read_unlock_bh(&nf_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 void *inf,
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const struct xt_match *match,
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void *matchinfo,
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unsigned int hook_mask)
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{
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struct xt_helper_info *info = matchinfo;
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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=%d\n", match->family);
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return 0;
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}
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info->name[29] = '\0';
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return 1;
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}
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static void
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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 xt_helper_match[] = {
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{
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.name = "helper",
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.family = AF_INET,
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.checkentry = check,
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.match = match,
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.destroy = destroy,
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.matchsize = sizeof(struct xt_helper_info),
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.me = THIS_MODULE,
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},
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{
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.name = "helper",
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.family = AF_INET6,
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.checkentry = check,
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.match = match,
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.destroy = destroy,
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.matchsize = sizeof(struct xt_helper_info),
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.me = THIS_MODULE,
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},
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};
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static int __init xt_helper_init(void)
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{
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return xt_register_matches(xt_helper_match,
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ARRAY_SIZE(xt_helper_match));
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}
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static void __exit xt_helper_fini(void)
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{
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xt_unregister_matches(xt_helper_match, ARRAY_SIZE(xt_helper_match));
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}
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module_init(xt_helper_init);
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module_exit(xt_helper_fini);
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