1 /*
2 * (C) 2007 by Sebastian Claßen <sebastian.classen@freenet.ag>
3 * (C) 2007-2010 by Jan Engelhardt <jengelh@medozas.de>
4 *
5 * Extracted from xt_TEE.c
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 or later, as
9 * published by the Free Software Foundation.
10 */
11 #include <linux/module.h>
12 #include <linux/percpu.h>
13 #include <linux/skbuff.h>
14 #include <linux/netfilter.h>
15 #include <net/ipv6.h>
16 #include <net/ip6_route.h>
17 #include <net/netfilter/ipv6/nf_dup_ipv6.h>
18 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
19 #include <net/netfilter/nf_conntrack.h>
20 #endif
21
22 static bool nf_dup_ipv6_route(struct net *net, struct sk_buff *skb,
23 const struct in6_addr *gw, int oif)
24 {
25 const struct ipv6hdr *iph = ipv6_hdr(skb);
26 struct dst_entry *dst;
27 struct flowi6 fl6;
28
29 memset(&fl6, 0, sizeof(fl6));
30 if (oif != -1)
31 fl6.flowi6_oif = oif;
32
33 fl6.daddr = *gw;
34 fl6.flowlabel = (__force __be32)(((iph->flow_lbl[0] & 0xF) << 16) |
35 (iph->flow_lbl[1] << 8) | iph->flow_lbl[2]);
36 fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
37 dst = ip6_route_output(net, NULL, &fl6);
38 if (dst->error) {
39 dst_release(dst);
40 return false;
41 }
42 skb_dst_drop(skb);
43 skb_dst_set(skb, dst);
44 skb->dev = dst->dev;
45 skb->protocol = htons(ETH_P_IPV6);
46
47 return true;
48 }
49
50 void nf_dup_ipv6(struct net *net, struct sk_buff *skb, unsigned int hooknum,
51 const struct in6_addr *gw, int oif)
52 {
53 if (this_cpu_read(nf_skb_duplicated))
54 return;
55 skb = pskb_copy(skb, GFP_ATOMIC);
56 if (skb == NULL)
57 return;
58
59 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
60 nf_reset(skb);
61 nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
62 #endif
63 if (hooknum == NF_INET_PRE_ROUTING ||
64 hooknum == NF_INET_LOCAL_IN) {
65 struct ipv6hdr *iph = ipv6_hdr(skb);
66 --iph->hop_limit;
67 }
68 if (nf_dup_ipv6_route(net, skb, gw, oif)) {
69 __this_cpu_write(nf_skb_duplicated, true);
70 ip6_local_out(net, skb->sk, skb);
71 __this_cpu_write(nf_skb_duplicated, false);
72 } else {
73 kfree_skb(skb);
74 }
75 }
76 EXPORT_SYMBOL_GPL(nf_dup_ipv6);
77
78 MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
79 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
80 MODULE_DESCRIPTION("nf_dup_ipv6: IPv6 packet duplication");
81 MODULE_LICENSE("GPL");
82
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