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