135 lines
3.7 KiB
C
135 lines
3.7 KiB
C
/*
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* iptables module to match inet_addr_type() of an ip.
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*
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* Copyright (c) 2004 Patrick McHardy <kaber@trash.net>
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* (C) 2007 Laszlo Attila Toth <panther@balabit.hu>
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/ip.h>
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#include <net/route.h>
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#include <linux/netfilter_ipv4/ipt_addrtype.h>
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#include <linux/netfilter/x_tables.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_DESCRIPTION("Xtables: address type match for IPv4");
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static inline bool match_type(struct net *net, const struct net_device *dev,
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__be32 addr, u_int16_t mask)
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{
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return !!(mask & (1 << inet_dev_addr_type(net, dev, addr)));
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}
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static bool
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addrtype_mt_v0(const struct sk_buff *skb, struct xt_action_param *par)
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{
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struct net *net = dev_net(par->in ? par->in : par->out);
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const struct ipt_addrtype_info *info = par->matchinfo;
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const struct iphdr *iph = ip_hdr(skb);
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bool ret = true;
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if (info->source)
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ret &= match_type(net, NULL, iph->saddr, info->source) ^
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info->invert_source;
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if (info->dest)
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ret &= match_type(net, NULL, iph->daddr, info->dest) ^
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info->invert_dest;
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return ret;
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}
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static bool
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addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
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{
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struct net *net = dev_net(par->in ? par->in : par->out);
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const struct ipt_addrtype_info_v1 *info = par->matchinfo;
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const struct iphdr *iph = ip_hdr(skb);
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const struct net_device *dev = NULL;
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bool ret = true;
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if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN)
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dev = par->in;
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else if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT)
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dev = par->out;
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if (info->source)
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ret &= match_type(net, dev, iph->saddr, info->source) ^
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(info->flags & IPT_ADDRTYPE_INVERT_SOURCE);
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if (ret && info->dest)
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ret &= match_type(net, dev, iph->daddr, info->dest) ^
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!!(info->flags & IPT_ADDRTYPE_INVERT_DEST);
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return ret;
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}
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static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par)
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{
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struct ipt_addrtype_info_v1 *info = par->matchinfo;
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if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN &&
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info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT) {
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pr_info("both incoming and outgoing "
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"interface limitation cannot be selected\n");
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return -EINVAL;
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}
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if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) |
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(1 << NF_INET_LOCAL_IN)) &&
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info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT) {
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pr_info("output interface limitation "
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"not valid in PREROUTING and INPUT\n");
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return -EINVAL;
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}
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if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) |
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(1 << NF_INET_LOCAL_OUT)) &&
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info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN) {
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pr_info("input interface limitation "
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"not valid in POSTROUTING and OUTPUT\n");
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return -EINVAL;
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}
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return 0;
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}
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static struct xt_match addrtype_mt_reg[] __read_mostly = {
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{
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.name = "addrtype",
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.family = NFPROTO_IPV4,
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.match = addrtype_mt_v0,
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.matchsize = sizeof(struct ipt_addrtype_info),
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.me = THIS_MODULE
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},
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{
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.name = "addrtype",
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.family = NFPROTO_IPV4,
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.revision = 1,
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.match = addrtype_mt_v1,
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.checkentry = addrtype_mt_checkentry_v1,
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.matchsize = sizeof(struct ipt_addrtype_info_v1),
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.me = THIS_MODULE
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}
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};
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static int __init addrtype_mt_init(void)
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{
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return xt_register_matches(addrtype_mt_reg,
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ARRAY_SIZE(addrtype_mt_reg));
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}
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static void __exit addrtype_mt_exit(void)
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{
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xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg));
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}
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module_init(addrtype_mt_init);
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module_exit(addrtype_mt_exit);
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