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- /*
- * (C) 2007 by Sebastian Claßen <sebastian.classen@freenet.ag>
- * (C) 2007-2010 by Jan Engelhardt <jengelh@medozas.de>
- *
- * Extracted from xt_TEE.c
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 or later, as
- * published by the Free Software Foundation.
- */
- #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)
- {
- if (this_cpu_read(nf_skb_duplicated))
- return;
- skb = pskb_copy(skb, GFP_ATOMIC);
- if (skb == NULL)
- return;
- #if IS_ENABLED(CONFIG_NF_CONNTRACK)
- nf_conntrack_put(skb->nfct);
- skb->nfct = &nf_ct_untracked_get()->ct_general;
- skb->nfctinfo = IP_CT_NEW;
- nf_conntrack_get(skb->nfct);
- #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);
- }
- }
- 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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