114 lines
2.7 KiB
C
114 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
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* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
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*
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* Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6
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* NAT funded by Astaro.
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*/
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#include <linux/if.h>
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#include <linux/inetdevice.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/netfilter.h>
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#include <linux/types.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter_ipv6.h>
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#include <linux/netfilter/x_tables.h>
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#include <net/addrconf.h>
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#include <net/checksum.h>
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#include <net/protocol.h>
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#include <net/netfilter/nf_nat.h>
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#include <net/netfilter/nf_nat_redirect.h>
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static unsigned int
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nf_nat_redirect(struct sk_buff *skb, const struct nf_nat_range2 *range,
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const union nf_inet_addr *newdst)
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{
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struct nf_nat_range2 newrange;
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enum ip_conntrack_info ctinfo;
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struct nf_conn *ct;
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ct = nf_ct_get(skb, &ctinfo);
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memset(&newrange, 0, sizeof(newrange));
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newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
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newrange.min_addr = *newdst;
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newrange.max_addr = *newdst;
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newrange.min_proto = range->min_proto;
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newrange.max_proto = range->max_proto;
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return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
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}
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unsigned int
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nf_nat_redirect_ipv4(struct sk_buff *skb, const struct nf_nat_range2 *range,
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unsigned int hooknum)
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{
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union nf_inet_addr newdst = {};
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WARN_ON(hooknum != NF_INET_PRE_ROUTING &&
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hooknum != NF_INET_LOCAL_OUT);
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/* Local packets: make them go to loopback */
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if (hooknum == NF_INET_LOCAL_OUT) {
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newdst.ip = htonl(INADDR_LOOPBACK);
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} else {
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const struct in_device *indev;
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indev = __in_dev_get_rcu(skb->dev);
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if (indev) {
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const struct in_ifaddr *ifa;
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ifa = rcu_dereference(indev->ifa_list);
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if (ifa)
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newdst.ip = ifa->ifa_local;
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}
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if (!newdst.ip)
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return NF_DROP;
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}
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return nf_nat_redirect(skb, range, &newdst);
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}
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EXPORT_SYMBOL_GPL(nf_nat_redirect_ipv4);
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static const struct in6_addr loopback_addr = IN6ADDR_LOOPBACK_INIT;
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unsigned int
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nf_nat_redirect_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
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unsigned int hooknum)
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{
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union nf_inet_addr newdst = {};
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if (hooknum == NF_INET_LOCAL_OUT) {
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newdst.in6 = loopback_addr;
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} else {
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struct inet6_dev *idev;
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struct inet6_ifaddr *ifa;
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bool addr = false;
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idev = __in6_dev_get(skb->dev);
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if (idev != NULL) {
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read_lock_bh(&idev->lock);
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list_for_each_entry(ifa, &idev->addr_list, if_list) {
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newdst.in6 = ifa->addr;
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addr = true;
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break;
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}
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read_unlock_bh(&idev->lock);
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}
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if (!addr)
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return NF_DROP;
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}
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return nf_nat_redirect(skb, range, &newdst);
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}
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EXPORT_SYMBOL_GPL(nf_nat_redirect_ipv6);
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