1 // SPDX-License-Identifier: GPL-2.0-only
3 * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6
5 * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
6 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
8 #include <linux/module.h>
9 #include <linux/netfilter_ipv6/ip6_tables.h>
10 #include <linux/slab.h>
13 MODULE_LICENSE("GPL");
14 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
15 MODULE_DESCRIPTION("ip6tables mangle table");
17 #define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
18 (1 << NF_INET_LOCAL_IN) | \
19 (1 << NF_INET_FORWARD) | \
20 (1 << NF_INET_LOCAL_OUT) | \
21 (1 << NF_INET_POST_ROUTING))
23 static int __net_init ip6table_mangle_table_init(struct net *net);
25 static const struct xt_table packet_mangler = {
27 .valid_hooks = MANGLE_VALID_HOOKS,
30 .priority = NF_IP6_PRI_MANGLE,
31 .table_init = ip6table_mangle_table_init,
35 ip6t_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state)
38 struct in6_addr saddr, daddr;
40 u_int32_t flowlabel, mark;
43 /* save source/dest address, mark, hoplimit, flowlabel, priority, */
44 memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
45 memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
47 hop_limit = ipv6_hdr(skb)->hop_limit;
49 /* flowlabel and prio (includes version, which shouldn't change either */
50 flowlabel = *((u_int32_t *)ipv6_hdr(skb));
52 ret = ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle);
54 if (ret != NF_DROP && ret != NF_STOLEN &&
55 (!ipv6_addr_equal(&ipv6_hdr(skb)->saddr, &saddr) ||
56 !ipv6_addr_equal(&ipv6_hdr(skb)->daddr, &daddr) ||
58 ipv6_hdr(skb)->hop_limit != hop_limit ||
59 flowlabel != *((u_int32_t *)ipv6_hdr(skb)))) {
60 err = ip6_route_me_harder(state->net, state->sk, skb);
62 ret = NF_DROP_ERR(err);
68 /* The work comes in here from netfilter.c. */
70 ip6table_mangle_hook(void *priv, struct sk_buff *skb,
71 const struct nf_hook_state *state)
73 if (state->hook == NF_INET_LOCAL_OUT)
74 return ip6t_mangle_out(skb, state);
75 return ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle);
78 static struct nf_hook_ops *mangle_ops __read_mostly;
79 static int __net_init ip6table_mangle_table_init(struct net *net)
81 struct ip6t_replace *repl;
84 if (net->ipv6.ip6table_mangle)
87 repl = ip6t_alloc_initial_table(&packet_mangler);
90 ret = ip6t_register_table(net, &packet_mangler, repl, mangle_ops,
91 &net->ipv6.ip6table_mangle);
96 static void __net_exit ip6table_mangle_net_pre_exit(struct net *net)
98 if (net->ipv6.ip6table_mangle)
99 ip6t_unregister_table_pre_exit(net, net->ipv6.ip6table_mangle,
103 static void __net_exit ip6table_mangle_net_exit(struct net *net)
105 if (!net->ipv6.ip6table_mangle)
108 ip6t_unregister_table_exit(net, net->ipv6.ip6table_mangle);
109 net->ipv6.ip6table_mangle = NULL;
112 static struct pernet_operations ip6table_mangle_net_ops = {
113 .pre_exit = ip6table_mangle_net_pre_exit,
114 .exit = ip6table_mangle_net_exit,
117 static int __init ip6table_mangle_init(void)
121 mangle_ops = xt_hook_ops_alloc(&packet_mangler, ip6table_mangle_hook);
122 if (IS_ERR(mangle_ops))
123 return PTR_ERR(mangle_ops);
125 ret = register_pernet_subsys(&ip6table_mangle_net_ops);
131 ret = ip6table_mangle_table_init(&init_net);
133 unregister_pernet_subsys(&ip6table_mangle_net_ops);
139 static void __exit ip6table_mangle_fini(void)
141 unregister_pernet_subsys(&ip6table_mangle_net_ops);
145 module_init(ip6table_mangle_init);
146 module_exit(ip6table_mangle_fini);