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![Jan Engelhardt](/assets/img/avatar_default.png)
Combine more modules since the actual code is so small anyway that the kmod metadata and the module in its loaded state totally outweighs the combined actual code size. IP_NF_TARGET_REDIRECT becomes a compat option; IP6_NF_TARGET_REDIRECT is completely eliminated since it has not see a release yet. Signed-off-by: Jan Engelhardt <jengelh@inai.de> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
190 lines
4.9 KiB
C
190 lines
4.9 KiB
C
/*
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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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* 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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* 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/ip.h>
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#include <linux/kernel.h>
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#include <linux/module.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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static const struct in6_addr loopback_addr = IN6ADDR_LOOPBACK_INIT;
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static unsigned int
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redirect_tg6(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct nf_nat_range *range = par->targinfo;
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struct nf_nat_range newrange;
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struct in6_addr newdst;
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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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if (par->hooknum == NF_INET_LOCAL_OUT)
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newdst = 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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rcu_read_lock();
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idev = __in6_dev_get(skb->dev);
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if (idev != NULL) {
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list_for_each_entry(ifa, &idev->addr_list, if_list) {
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newdst = ifa->addr;
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addr = true;
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break;
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}
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}
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rcu_read_unlock();
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if (!addr)
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return NF_DROP;
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}
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newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
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newrange.min_addr.in6 = newdst;
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newrange.max_addr.in6 = 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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static int redirect_tg6_checkentry(const struct xt_tgchk_param *par)
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{
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const struct nf_nat_range *range = par->targinfo;
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if (range->flags & NF_NAT_RANGE_MAP_IPS)
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return -EINVAL;
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return 0;
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}
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/* FIXME: Take multiple ranges --RR */
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static int redirect_tg4_check(const struct xt_tgchk_param *par)
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{
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const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
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if (mr->range[0].flags & NF_NAT_RANGE_MAP_IPS) {
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pr_debug("bad MAP_IPS.\n");
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return -EINVAL;
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}
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if (mr->rangesize != 1) {
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pr_debug("bad rangesize %u.\n", mr->rangesize);
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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 unsigned int
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redirect_tg4(struct sk_buff *skb, const struct xt_action_param *par)
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{
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struct nf_conn *ct;
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enum ip_conntrack_info ctinfo;
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__be32 newdst;
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const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
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struct nf_nat_range newrange;
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NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING ||
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par->hooknum == NF_INET_LOCAL_OUT);
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ct = nf_ct_get(skb, &ctinfo);
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NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
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/* Local packets: make them go to loopback */
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if (par->hooknum == NF_INET_LOCAL_OUT)
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newdst = htonl(0x7F000001);
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else {
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struct in_device *indev;
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struct in_ifaddr *ifa;
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newdst = 0;
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rcu_read_lock();
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indev = __in_dev_get_rcu(skb->dev);
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if (indev && (ifa = indev->ifa_list))
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newdst = ifa->ifa_local;
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rcu_read_unlock();
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if (!newdst)
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return NF_DROP;
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}
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/* Transfer from original range. */
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memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
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memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
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newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
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newrange.min_addr.ip = newdst;
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newrange.max_addr.ip = newdst;
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newrange.min_proto = mr->range[0].min;
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newrange.max_proto = mr->range[0].max;
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/* Hand modified range to generic setup. */
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return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
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}
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static struct xt_target redirect_tg_reg[] __read_mostly = {
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{
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.name = "REDIRECT",
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.family = NFPROTO_IPV6,
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.revision = 0,
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.table = "nat",
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.checkentry = redirect_tg6_checkentry,
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.target = redirect_tg6,
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.targetsize = sizeof(struct nf_nat_range),
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.hooks = (1 << NF_INET_PRE_ROUTING) |
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(1 << NF_INET_LOCAL_OUT),
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.me = THIS_MODULE,
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},
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{
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.name = "REDIRECT",
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.family = NFPROTO_IPV4,
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.revision = 0,
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.table = "nat",
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.target = redirect_tg4,
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.checkentry = redirect_tg4_check,
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.targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
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.hooks = (1 << NF_INET_PRE_ROUTING) |
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(1 << NF_INET_LOCAL_OUT),
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.me = THIS_MODULE,
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},
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};
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static int __init redirect_tg_init(void)
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{
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return xt_register_targets(redirect_tg_reg,
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ARRAY_SIZE(redirect_tg_reg));
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}
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static void __exit redirect_tg_exit(void)
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{
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xt_unregister_targets(redirect_tg_reg, ARRAY_SIZE(redirect_tg_reg));
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}
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module_init(redirect_tg_init);
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module_exit(redirect_tg_exit);
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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: Connection redirection to localhost");
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MODULE_ALIAS("ip6t_REDIRECT");
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MODULE_ALIAS("ipt_REDIRECT");
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