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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* (C) 2007 by Sebastian Claßen <sebastian.classen@freenet.ag>
* (C) 2007-2010 by Jan Engelhardt <jengelh@medozas.de>
*
* Extracted from xt_TEE.c
*/
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/netfilter/ipv6/nf_dup_ipv6.h>
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#include <net/netfilter/nf_conntrack.h>
#endif
static bool nf_dup_ipv6_route(struct net *net, struct sk_buff *skb,
const struct in6_addr *gw, int oif)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
struct dst_entry *dst;
struct flowi6 fl6;
memset(&fl6, 0, sizeof(fl6));
if (oif != -1)
fl6.flowi6_oif = oif;
fl6.daddr = *gw;
fl6.flowlabel = (__force __be32)(((iph->flow_lbl[0] & 0xF) << 16) |
(iph->flow_lbl[1] << 8) | iph->flow_lbl[2]);
fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
dst = ip6_route_output(net, NULL, &fl6);
if (dst->error) {
dst_release(dst);
return false;
}
skb_dst_drop(skb);
skb_dst_set(skb, dst);
skb->dev = dst->dev;
skb->protocol = htons(ETH_P_IPV6);
return true;
}
void nf_dup_ipv6(struct net *net, struct sk_buff *skb, unsigned int hooknum,
const struct in6_addr *gw, int oif)
{
local_bh_disable();
if (this_cpu_read(nf_skb_duplicated))
goto out;
skb = pskb_copy(skb, GFP_ATOMIC);
if (skb == NULL)
goto out;
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
nf_reset_ct(skb);
nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
#endif
if (hooknum == NF_INET_PRE_ROUTING ||
hooknum == NF_INET_LOCAL_IN) {
struct ipv6hdr *iph = ipv6_hdr(skb);
--iph->hop_limit;
}
if (nf_dup_ipv6_route(net, skb, gw, oif)) {
__this_cpu_write(nf_skb_duplicated, true);
ip6_local_out(net, skb->sk, skb);
__this_cpu_write(nf_skb_duplicated, false);
} else {
kfree_skb(skb);
}
out:
local_bh_enable();
}
EXPORT_SYMBOL_GPL(nf_dup_ipv6);
MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
MODULE_DESCRIPTION("nf_dup_ipv6: IPv6 packet duplication");
MODULE_LICENSE("GPL");
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