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1da177e4 LT |
1 | /* |
2 | * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6 | |
3 | * | |
4 | * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org> | |
5 | * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org> | |
6 | * | |
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. | |
1da177e4 LT |
10 | */ |
11 | #include <linux/module.h> | |
12 | #include <linux/netfilter_ipv6/ip6_tables.h> | |
5a0e3ad6 | 13 | #include <linux/slab.h> |
d9e85655 | 14 | #include <net/ipv6.h> |
1da177e4 LT |
15 | |
16 | MODULE_LICENSE("GPL"); | |
17 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
18 | MODULE_DESCRIPTION("ip6tables mangle table"); | |
19 | ||
6e23ae2a PM |
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)) | |
1da177e4 | 25 | |
b9e69e12 FW |
26 | static int __net_init ip6table_mangle_table_init(struct net *net); |
27 | ||
35aad0ff | 28 | static const struct xt_table packet_mangler = { |
1da177e4 LT |
29 | .name = "mangle", |
30 | .valid_hooks = MANGLE_VALID_HOOKS, | |
1da177e4 | 31 | .me = THIS_MODULE, |
f88e6a8a | 32 | .af = NFPROTO_IPV6, |
2b95efe7 | 33 | .priority = NF_IP6_PRI_MANGLE, |
b9e69e12 | 34 | .table_init = ip6table_mangle_table_init, |
1da177e4 LT |
35 | }; |
36 | ||
7dd1b8da | 37 | static unsigned int |
8f8a3715 | 38 | ip6t_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state) |
1da177e4 | 39 | { |
1da177e4 LT |
40 | unsigned int ret; |
41 | struct in6_addr saddr, daddr; | |
42 | u_int8_t hop_limit; | |
82e91ffe | 43 | u_int32_t flowlabel, mark; |
58e35d14 | 44 | int err; |
1da177e4 LT |
45 | #if 0 |
46 | /* root is playing with raw sockets. */ | |
3666ed1c JP |
47 | if (skb->len < sizeof(struct iphdr) || |
48 | ip_hdrlen(skb) < sizeof(struct iphdr)) { | |
e87cc472 | 49 | net_warn_ratelimited("ip6t_hook: happy cracking\n"); |
1da177e4 LT |
50 | return NF_ACCEPT; |
51 | } | |
52 | #endif | |
53 | ||
82e91ffe | 54 | /* save source/dest address, mark, hoplimit, flowlabel, priority, */ |
3db05fea HX |
55 | memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr)); |
56 | memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr)); | |
57 | mark = skb->mark; | |
58 | hop_limit = ipv6_hdr(skb)->hop_limit; | |
1da177e4 LT |
59 | |
60 | /* flowlabel and prio (includes version, which shouldn't change either */ | |
3db05fea | 61 | flowlabel = *((u_int32_t *)ipv6_hdr(skb)); |
1da177e4 | 62 | |
6cb8ff3f | 63 | ret = ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle); |
1da177e4 | 64 | |
3666ed1c | 65 | if (ret != NF_DROP && ret != NF_STOLEN && |
d9e85655 YH |
66 | (!ipv6_addr_equal(&ipv6_hdr(skb)->saddr, &saddr) || |
67 | !ipv6_addr_equal(&ipv6_hdr(skb)->daddr, &daddr) || | |
3666ed1c | 68 | skb->mark != mark || |
b169f6db | 69 | ipv6_hdr(skb)->hop_limit != hop_limit || |
58e35d14 | 70 | flowlabel != *((u_int32_t *)ipv6_hdr(skb)))) { |
5f5d74d7 | 71 | err = ip6_route_me_harder(state->net, skb); |
58e35d14 PM |
72 | if (err < 0) |
73 | ret = NF_DROP_ERR(err); | |
74 | } | |
1da177e4 LT |
75 | |
76 | return ret; | |
77 | } | |
78 | ||
737535c5 JE |
79 | /* The work comes in here from netfilter.c. */ |
80 | static unsigned int | |
06198b34 | 81 | ip6table_mangle_hook(void *priv, struct sk_buff *skb, |
238e54c9 | 82 | const struct nf_hook_state *state) |
737535c5 | 83 | { |
6cb8ff3f | 84 | if (state->hook == NF_INET_LOCAL_OUT) |
8f8a3715 | 85 | return ip6t_mangle_out(skb, state); |
6cb8ff3f | 86 | return ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle); |
737535c5 JE |
87 | } |
88 | ||
2b95efe7 | 89 | static struct nf_hook_ops *mangle_ops __read_mostly; |
b9e69e12 | 90 | static int __net_init ip6table_mangle_table_init(struct net *net) |
8280aa61 | 91 | { |
e3eaa991 | 92 | struct ip6t_replace *repl; |
a67dd266 | 93 | int ret; |
e3eaa991 | 94 | |
b9e69e12 FW |
95 | if (net->ipv6.ip6table_mangle) |
96 | return 0; | |
97 | ||
e3eaa991 JE |
98 | repl = ip6t_alloc_initial_table(&packet_mangler); |
99 | if (repl == NULL) | |
100 | return -ENOMEM; | |
a67dd266 FW |
101 | ret = ip6t_register_table(net, &packet_mangler, repl, mangle_ops, |
102 | &net->ipv6.ip6table_mangle); | |
e3eaa991 | 103 | kfree(repl); |
a67dd266 | 104 | return ret; |
8280aa61 AD |
105 | } |
106 | ||
107 | static void __net_exit ip6table_mangle_net_exit(struct net *net) | |
108 | { | |
b9e69e12 FW |
109 | if (!net->ipv6.ip6table_mangle) |
110 | return; | |
111 | ||
a67dd266 | 112 | ip6t_unregister_table(net, net->ipv6.ip6table_mangle, mangle_ops); |
b9e69e12 | 113 | net->ipv6.ip6table_mangle = NULL; |
8280aa61 AD |
114 | } |
115 | ||
116 | static struct pernet_operations ip6table_mangle_net_ops = { | |
8280aa61 AD |
117 | .exit = ip6table_mangle_net_exit, |
118 | }; | |
119 | ||
65b4b4e8 | 120 | static int __init ip6table_mangle_init(void) |
1da177e4 LT |
121 | { |
122 | int ret; | |
123 | ||
b9e69e12 FW |
124 | mangle_ops = xt_hook_ops_alloc(&packet_mangler, ip6table_mangle_hook); |
125 | if (IS_ERR(mangle_ops)) | |
126 | return PTR_ERR(mangle_ops); | |
127 | ||
8280aa61 | 128 | ret = register_pernet_subsys(&ip6table_mangle_net_ops); |
b9e69e12 FW |
129 | if (ret < 0) { |
130 | kfree(mangle_ops); | |
8280aa61 | 131 | return ret; |
2b95efe7 | 132 | } |
1da177e4 | 133 | |
b9e69e12 FW |
134 | ret = ip6table_mangle_table_init(&init_net); |
135 | if (ret) { | |
136 | unregister_pernet_subsys(&ip6table_mangle_net_ops); | |
137 | kfree(mangle_ops); | |
138 | } | |
1da177e4 LT |
139 | return ret; |
140 | } | |
141 | ||
65b4b4e8 | 142 | static void __exit ip6table_mangle_fini(void) |
1da177e4 | 143 | { |
8280aa61 | 144 | unregister_pernet_subsys(&ip6table_mangle_net_ops); |
b9e69e12 | 145 | kfree(mangle_ops); |
1da177e4 LT |
146 | } |
147 | ||
65b4b4e8 AM |
148 | module_init(ip6table_mangle_init); |
149 | module_exit(ip6table_mangle_fini); |