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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> | |
13 | ||
14 | MODULE_LICENSE("GPL"); | |
15 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
16 | MODULE_DESCRIPTION("ip6tables mangle table"); | |
17 | ||
6e23ae2a PM |
18 | #define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \ |
19 | (1 << NF_INET_LOCAL_IN) | \ | |
20 | (1 << NF_INET_FORWARD) | \ | |
21 | (1 << NF_INET_LOCAL_OUT) | \ | |
22 | (1 << NF_INET_POST_ROUTING)) | |
1da177e4 | 23 | |
1da177e4 LT |
24 | static struct |
25 | { | |
26 | struct ip6t_replace repl; | |
27 | struct ip6t_standard entries[5]; | |
28 | struct ip6t_error term; | |
3c2ad469 PM |
29 | } initial_table __initdata = { |
30 | .repl = { | |
31 | .name = "mangle", | |
32 | .valid_hooks = MANGLE_VALID_HOOKS, | |
33 | .num_entries = 6, | |
34 | .size = sizeof(struct ip6t_standard) * 5 + sizeof(struct ip6t_error), | |
35 | .hook_entry = { | |
6e23ae2a PM |
36 | [NF_INET_PRE_ROUTING] = 0, |
37 | [NF_INET_LOCAL_IN] = sizeof(struct ip6t_standard), | |
38 | [NF_INET_FORWARD] = sizeof(struct ip6t_standard) * 2, | |
39 | [NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 3, | |
40 | [NF_INET_POST_ROUTING] = sizeof(struct ip6t_standard) * 4, | |
3c2ad469 PM |
41 | }, |
42 | .underflow = { | |
6e23ae2a PM |
43 | [NF_INET_PRE_ROUTING] = 0, |
44 | [NF_INET_LOCAL_IN] = sizeof(struct ip6t_standard), | |
45 | [NF_INET_FORWARD] = sizeof(struct ip6t_standard) * 2, | |
46 | [NF_INET_LOCAL_OUT] = sizeof(struct ip6t_standard) * 3, | |
47 | [NF_INET_POST_ROUTING] = sizeof(struct ip6t_standard) * 4, | |
3c2ad469 PM |
48 | }, |
49 | }, | |
50 | .entries = { | |
51 | IP6T_STANDARD_INIT(NF_ACCEPT), /* PRE_ROUTING */ | |
52 | IP6T_STANDARD_INIT(NF_ACCEPT), /* LOCAL_IN */ | |
53 | IP6T_STANDARD_INIT(NF_ACCEPT), /* FORWARD */ | |
54 | IP6T_STANDARD_INIT(NF_ACCEPT), /* LOCAL_OUT */ | |
55 | IP6T_STANDARD_INIT(NF_ACCEPT), /* POST_ROUTING */ | |
56 | }, | |
57 | .term = IP6T_ERROR_INIT, /* ERROR */ | |
1da177e4 LT |
58 | }; |
59 | ||
e60a13e0 | 60 | static struct xt_table packet_mangler = { |
1da177e4 LT |
61 | .name = "mangle", |
62 | .valid_hooks = MANGLE_VALID_HOOKS, | |
63 | .lock = RW_LOCK_UNLOCKED, | |
64 | .me = THIS_MODULE, | |
2e4e6a17 | 65 | .af = AF_INET6, |
1da177e4 LT |
66 | }; |
67 | ||
68 | /* The work comes in here from netfilter.c. */ | |
69 | static unsigned int | |
70 | ip6t_route_hook(unsigned int hook, | |
3db05fea | 71 | struct sk_buff *skb, |
1da177e4 LT |
72 | const struct net_device *in, |
73 | const struct net_device *out, | |
74 | int (*okfn)(struct sk_buff *)) | |
75 | { | |
3db05fea | 76 | return ip6t_do_table(skb, hook, in, out, &packet_mangler); |
1da177e4 LT |
77 | } |
78 | ||
79 | static unsigned int | |
80 | ip6t_local_hook(unsigned int hook, | |
3db05fea | 81 | struct sk_buff *skb, |
1da177e4 LT |
82 | const struct net_device *in, |
83 | const struct net_device *out, | |
84 | int (*okfn)(struct sk_buff *)) | |
85 | { | |
86 | ||
1da177e4 LT |
87 | unsigned int ret; |
88 | struct in6_addr saddr, daddr; | |
89 | u_int8_t hop_limit; | |
82e91ffe | 90 | u_int32_t flowlabel, mark; |
1da177e4 LT |
91 | |
92 | #if 0 | |
93 | /* root is playing with raw sockets. */ | |
3db05fea HX |
94 | if (skb->len < sizeof(struct iphdr) |
95 | || ip_hdrlen(skb) < sizeof(struct iphdr)) { | |
1da177e4 LT |
96 | if (net_ratelimit()) |
97 | printk("ip6t_hook: happy cracking.\n"); | |
98 | return NF_ACCEPT; | |
99 | } | |
100 | #endif | |
101 | ||
82e91ffe | 102 | /* save source/dest address, mark, hoplimit, flowlabel, priority, */ |
3db05fea HX |
103 | memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr)); |
104 | memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr)); | |
105 | mark = skb->mark; | |
106 | hop_limit = ipv6_hdr(skb)->hop_limit; | |
1da177e4 LT |
107 | |
108 | /* flowlabel and prio (includes version, which shouldn't change either */ | |
3db05fea | 109 | flowlabel = *((u_int32_t *)ipv6_hdr(skb)); |
1da177e4 | 110 | |
3db05fea | 111 | ret = ip6t_do_table(skb, hook, in, out, &packet_mangler); |
1da177e4 | 112 | |
1ab1457c | 113 | if (ret != NF_DROP && ret != NF_STOLEN |
3db05fea HX |
114 | && (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) |
115 | || memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) | |
116 | || skb->mark != mark | |
117 | || ipv6_hdr(skb)->hop_limit != hop_limit)) | |
118 | return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP; | |
1da177e4 LT |
119 | |
120 | return ret; | |
121 | } | |
122 | ||
1999414a | 123 | static struct nf_hook_ops ip6t_ops[] __read_mostly = { |
1da177e4 LT |
124 | { |
125 | .hook = ip6t_route_hook, | |
126 | .owner = THIS_MODULE, | |
127 | .pf = PF_INET6, | |
6e23ae2a | 128 | .hooknum = NF_INET_PRE_ROUTING, |
1da177e4 LT |
129 | .priority = NF_IP6_PRI_MANGLE, |
130 | }, | |
131 | { | |
132 | .hook = ip6t_local_hook, | |
133 | .owner = THIS_MODULE, | |
134 | .pf = PF_INET6, | |
6e23ae2a | 135 | .hooknum = NF_INET_LOCAL_IN, |
1da177e4 LT |
136 | .priority = NF_IP6_PRI_MANGLE, |
137 | }, | |
138 | { | |
139 | .hook = ip6t_route_hook, | |
140 | .owner = THIS_MODULE, | |
141 | .pf = PF_INET6, | |
6e23ae2a | 142 | .hooknum = NF_INET_FORWARD, |
1da177e4 LT |
143 | .priority = NF_IP6_PRI_MANGLE, |
144 | }, | |
145 | { | |
146 | .hook = ip6t_local_hook, | |
147 | .owner = THIS_MODULE, | |
148 | .pf = PF_INET6, | |
6e23ae2a | 149 | .hooknum = NF_INET_LOCAL_OUT, |
1da177e4 LT |
150 | .priority = NF_IP6_PRI_MANGLE, |
151 | }, | |
152 | { | |
153 | .hook = ip6t_route_hook, | |
154 | .owner = THIS_MODULE, | |
155 | .pf = PF_INET6, | |
6e23ae2a | 156 | .hooknum = NF_INET_POST_ROUTING, |
1da177e4 LT |
157 | .priority = NF_IP6_PRI_MANGLE, |
158 | }, | |
159 | }; | |
160 | ||
65b4b4e8 | 161 | static int __init ip6table_mangle_init(void) |
1da177e4 LT |
162 | { |
163 | int ret; | |
164 | ||
165 | /* Register table */ | |
166 | ret = ip6t_register_table(&packet_mangler, &initial_table.repl); | |
167 | if (ret < 0) | |
168 | return ret; | |
169 | ||
170 | /* Register hooks */ | |
964ddaa1 | 171 | ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); |
1da177e4 LT |
172 | if (ret < 0) |
173 | goto cleanup_table; | |
174 | ||
1da177e4 LT |
175 | return ret; |
176 | ||
1da177e4 LT |
177 | cleanup_table: |
178 | ip6t_unregister_table(&packet_mangler); | |
1da177e4 LT |
179 | return ret; |
180 | } | |
181 | ||
65b4b4e8 | 182 | static void __exit ip6table_mangle_fini(void) |
1da177e4 | 183 | { |
964ddaa1 | 184 | nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); |
1da177e4 LT |
185 | ip6t_unregister_table(&packet_mangler); |
186 | } | |
187 | ||
65b4b4e8 AM |
188 | module_init(ip6table_mangle_init); |
189 | module_exit(ip6table_mangle_fini); |