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https://github.com/torvalds/linux
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6f56ad1b92
`nf_nat_redirect_ipv4` takes a `struct nf_nat_ipv4_multi_range_compat`, but converts it internally to a `struct nf_nat_range2`. Change the function to take the latter, factor out the code now shared with `nf_nat_redirect_ipv6`, move the conversion to the xt_REDIRECT module, and update the ipv4 range initialization in the nft_redir module. Replace a bare hex constant for 127.0.0.1 with a macro. Remove `WARN_ON`. `nf_nat_setup_info` calls `nf_ct_is_confirmed`: /* Can't setup nat info for confirmed ct. */ if (nf_ct_is_confirmed(ct)) return NF_ACCEPT; This means that `ct` cannot be null or the kernel will crash, and implies that `ctinfo` is `IP_CT_NEW` or `IP_CT_RELATED`. nft_redir has separate ipv4 and ipv6 call-backs which share much of their code, and an inet one switch containing a switch that calls one of the others based on the family of the packet. Merge the ipv4 and ipv6 ones into the inet one in order to get rid of the duplicate code. Const-qualify the `priv` pointer since we don't need to write through it. Assign `priv->flags` to the range instead of OR-ing it in. Set the `NF_NAT_RANGE_PROTO_SPECIFIED` flag once during init, rather than on every eval. Signed-off-by: Jeremy Sowden <jeremy@azazel.net> Signed-off-by: Florian Westphal <fw@strlen.de>
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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