2 * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6
4 * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
5 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 #include <linux/module.h>
12 #include <linux/netfilter_ipv6/ip6_tables.h>
13 #include <linux/slab.h>
16 MODULE_LICENSE("GPL");
17 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
18 MODULE_DESCRIPTION("ip6tables mangle table");
20 #define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
21 (1 << NF_INET_LOCAL_IN) | \
22 (1 << NF_INET_FORWARD) | \
23 (1 << NF_INET_LOCAL_OUT) | \
24 (1 << NF_INET_POST_ROUTING))
26 static const struct xt_table packet_mangler
= {
28 .valid_hooks
= MANGLE_VALID_HOOKS
,
31 .priority
= NF_IP6_PRI_MANGLE
,
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 /* root is playing with raw sockets. */
44 if (skb
->len
< sizeof(struct iphdr
) ||
45 ip_hdrlen(skb
) < sizeof(struct iphdr
)) {
46 net_warn_ratelimited("ip6t_hook: happy cracking\n");
51 /* save source/dest address, mark, hoplimit, flowlabel, priority, */
52 memcpy(&saddr
, &ipv6_hdr(skb
)->saddr
, sizeof(saddr
));
53 memcpy(&daddr
, &ipv6_hdr(skb
)->daddr
, sizeof(daddr
));
55 hop_limit
= ipv6_hdr(skb
)->hop_limit
;
57 /* flowlabel and prio (includes version, which shouldn't change either */
58 flowlabel
= *((u_int32_t
*)ipv6_hdr(skb
));
60 ret
= ip6t_do_table(skb
, state
, state
->net
->ipv6
.ip6table_mangle
);
62 if (ret
!= NF_DROP
&& ret
!= NF_STOLEN
&&
63 (!ipv6_addr_equal(&ipv6_hdr(skb
)->saddr
, &saddr
) ||
64 !ipv6_addr_equal(&ipv6_hdr(skb
)->daddr
, &daddr
) ||
66 ipv6_hdr(skb
)->hop_limit
!= hop_limit
||
67 flowlabel
!= *((u_int32_t
*)ipv6_hdr(skb
)))) {
68 err
= ip6_route_me_harder(skb
);
70 ret
= NF_DROP_ERR(err
);
76 /* The work comes in here from netfilter.c. */
78 ip6table_mangle_hook(void *priv
, struct sk_buff
*skb
,
79 const struct nf_hook_state
*state
)
81 if (state
->hook
== NF_INET_LOCAL_OUT
)
82 return ip6t_mangle_out(skb
, state
);
83 if (state
->hook
== NF_INET_POST_ROUTING
)
84 return ip6t_do_table(skb
, state
,
85 state
->net
->ipv6
.ip6table_mangle
);
87 return ip6t_do_table(skb
, state
, state
->net
->ipv6
.ip6table_mangle
);
90 static struct nf_hook_ops
*mangle_ops __read_mostly
;
91 static int __net_init
ip6table_mangle_net_init(struct net
*net
)
93 struct ip6t_replace
*repl
;
95 repl
= ip6t_alloc_initial_table(&packet_mangler
);
98 net
->ipv6
.ip6table_mangle
=
99 ip6t_register_table(net
, &packet_mangler
, repl
);
101 return PTR_ERR_OR_ZERO(net
->ipv6
.ip6table_mangle
);
104 static void __net_exit
ip6table_mangle_net_exit(struct net
*net
)
106 ip6t_unregister_table(net
, net
->ipv6
.ip6table_mangle
);
109 static struct pernet_operations ip6table_mangle_net_ops
= {
110 .init
= ip6table_mangle_net_init
,
111 .exit
= ip6table_mangle_net_exit
,
114 static int __init
ip6table_mangle_init(void)
118 ret
= register_pernet_subsys(&ip6table_mangle_net_ops
);
123 mangle_ops
= xt_hook_link(&packet_mangler
, ip6table_mangle_hook
);
124 if (IS_ERR(mangle_ops
)) {
125 ret
= PTR_ERR(mangle_ops
);
132 unregister_pernet_subsys(&ip6table_mangle_net_ops
);
136 static void __exit
ip6table_mangle_fini(void)
138 xt_hook_unlink(&packet_mangler
, mangle_ops
);
139 unregister_pernet_subsys(&ip6table_mangle_net_ops
);
142 module_init(ip6table_mangle_init
);
143 module_exit(ip6table_mangle_fini
);