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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. | |
10 | * | |
11 | * Extended to all five netfilter hooks by Brad Chapman & Harald Welte | |
12 | */ | |
13 | #include <linux/module.h> | |
14 | #include <linux/netfilter_ipv6/ip6_tables.h> | |
15 | ||
16 | MODULE_LICENSE("GPL"); | |
17 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
18 | MODULE_DESCRIPTION("ip6tables mangle table"); | |
19 | ||
20 | #define MANGLE_VALID_HOOKS ((1 << NF_IP6_PRE_ROUTING) | \ | |
21 | (1 << NF_IP6_LOCAL_IN) | \ | |
22 | (1 << NF_IP6_FORWARD) | \ | |
23 | (1 << NF_IP6_LOCAL_OUT) | \ | |
24 | (1 << NF_IP6_POST_ROUTING)) | |
25 | ||
26 | #if 0 | |
27 | #define DEBUGP(x, args...) printk(KERN_DEBUG x, ## args) | |
28 | #else | |
29 | #define DEBUGP(x, args...) | |
30 | #endif | |
31 | ||
32 | /* Standard entry. */ | |
33 | struct ip6t_standard | |
34 | { | |
35 | struct ip6t_entry entry; | |
36 | struct ip6t_standard_target target; | |
37 | }; | |
38 | ||
39 | struct ip6t_error_target | |
40 | { | |
41 | struct ip6t_entry_target target; | |
42 | char errorname[IP6T_FUNCTION_MAXNAMELEN]; | |
43 | }; | |
44 | ||
45 | struct ip6t_error | |
46 | { | |
47 | struct ip6t_entry entry; | |
48 | struct ip6t_error_target target; | |
49 | }; | |
50 | ||
51 | static struct | |
52 | { | |
53 | struct ip6t_replace repl; | |
54 | struct ip6t_standard entries[5]; | |
55 | struct ip6t_error term; | |
56 | } initial_table __initdata | |
57 | = { { "mangle", MANGLE_VALID_HOOKS, 6, | |
58 | sizeof(struct ip6t_standard) * 5 + sizeof(struct ip6t_error), | |
59 | { [NF_IP6_PRE_ROUTING] = 0, | |
60 | [NF_IP6_LOCAL_IN] = sizeof(struct ip6t_standard), | |
61 | [NF_IP6_FORWARD] = sizeof(struct ip6t_standard) * 2, | |
62 | [NF_IP6_LOCAL_OUT] = sizeof(struct ip6t_standard) * 3, | |
63 | [NF_IP6_POST_ROUTING] = sizeof(struct ip6t_standard) * 4}, | |
64 | { [NF_IP6_PRE_ROUTING] = 0, | |
65 | [NF_IP6_LOCAL_IN] = sizeof(struct ip6t_standard), | |
66 | [NF_IP6_FORWARD] = sizeof(struct ip6t_standard) * 2, | |
67 | [NF_IP6_LOCAL_OUT] = sizeof(struct ip6t_standard) * 3, | |
68 | [NF_IP6_POST_ROUTING] = sizeof(struct ip6t_standard) * 4}, | |
69 | 0, NULL, { } }, | |
70 | { | |
71 | /* PRE_ROUTING */ | |
72 | { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, | |
73 | 0, | |
74 | sizeof(struct ip6t_entry), | |
75 | sizeof(struct ip6t_standard), | |
76 | 0, { 0, 0 }, { } }, | |
77 | { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } }, | |
78 | -NF_ACCEPT - 1 } }, | |
79 | /* LOCAL_IN */ | |
80 | { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, | |
81 | 0, | |
82 | sizeof(struct ip6t_entry), | |
83 | sizeof(struct ip6t_standard), | |
84 | 0, { 0, 0 }, { } }, | |
85 | { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } }, | |
86 | -NF_ACCEPT - 1 } }, | |
87 | /* FORWARD */ | |
88 | { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, | |
89 | 0, | |
90 | sizeof(struct ip6t_entry), | |
91 | sizeof(struct ip6t_standard), | |
92 | 0, { 0, 0 }, { } }, | |
93 | { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } }, | |
94 | -NF_ACCEPT - 1 } }, | |
95 | /* LOCAL_OUT */ | |
96 | { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, | |
97 | 0, | |
98 | sizeof(struct ip6t_entry), | |
99 | sizeof(struct ip6t_standard), | |
100 | 0, { 0, 0 }, { } }, | |
101 | { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } }, | |
102 | -NF_ACCEPT - 1 } }, | |
103 | /* POST_ROUTING */ | |
104 | { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, | |
105 | 0, | |
106 | sizeof(struct ip6t_entry), | |
107 | sizeof(struct ip6t_standard), | |
108 | 0, { 0, 0 }, { } }, | |
109 | { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } }, | |
110 | -NF_ACCEPT - 1 } } | |
111 | }, | |
112 | /* ERROR */ | |
113 | { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 }, | |
114 | 0, | |
115 | sizeof(struct ip6t_entry), | |
116 | sizeof(struct ip6t_error), | |
117 | 0, { 0, 0 }, { } }, | |
118 | { { { { IP6T_ALIGN(sizeof(struct ip6t_error_target)), IP6T_ERROR_TARGET } }, | |
119 | { } }, | |
120 | "ERROR" | |
121 | } | |
122 | } | |
123 | }; | |
124 | ||
125 | static struct ip6t_table packet_mangler = { | |
126 | .name = "mangle", | |
127 | .valid_hooks = MANGLE_VALID_HOOKS, | |
128 | .lock = RW_LOCK_UNLOCKED, | |
129 | .me = THIS_MODULE, | |
2e4e6a17 | 130 | .af = AF_INET6, |
1da177e4 LT |
131 | }; |
132 | ||
133 | /* The work comes in here from netfilter.c. */ | |
134 | static unsigned int | |
135 | ip6t_route_hook(unsigned int hook, | |
136 | struct sk_buff **pskb, | |
137 | const struct net_device *in, | |
138 | const struct net_device *out, | |
139 | int (*okfn)(struct sk_buff *)) | |
140 | { | |
fe1cb108 | 141 | return ip6t_do_table(pskb, hook, in, out, &packet_mangler); |
1da177e4 LT |
142 | } |
143 | ||
144 | static unsigned int | |
145 | ip6t_local_hook(unsigned int hook, | |
146 | struct sk_buff **pskb, | |
147 | const struct net_device *in, | |
148 | const struct net_device *out, | |
149 | int (*okfn)(struct sk_buff *)) | |
150 | { | |
151 | ||
1da177e4 LT |
152 | unsigned int ret; |
153 | struct in6_addr saddr, daddr; | |
154 | u_int8_t hop_limit; | |
82e91ffe | 155 | u_int32_t flowlabel, mark; |
1da177e4 LT |
156 | |
157 | #if 0 | |
158 | /* root is playing with raw sockets. */ | |
159 | if ((*pskb)->len < sizeof(struct iphdr) | |
160 | || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) { | |
161 | if (net_ratelimit()) | |
162 | printk("ip6t_hook: happy cracking.\n"); | |
163 | return NF_ACCEPT; | |
164 | } | |
165 | #endif | |
166 | ||
82e91ffe | 167 | /* save source/dest address, mark, hoplimit, flowlabel, priority, */ |
1da177e4 LT |
168 | memcpy(&saddr, &(*pskb)->nh.ipv6h->saddr, sizeof(saddr)); |
169 | memcpy(&daddr, &(*pskb)->nh.ipv6h->daddr, sizeof(daddr)); | |
82e91ffe | 170 | mark = (*pskb)->mark; |
1da177e4 LT |
171 | hop_limit = (*pskb)->nh.ipv6h->hop_limit; |
172 | ||
173 | /* flowlabel and prio (includes version, which shouldn't change either */ | |
174 | flowlabel = *((u_int32_t *) (*pskb)->nh.ipv6h); | |
175 | ||
fe1cb108 | 176 | ret = ip6t_do_table(pskb, hook, in, out, &packet_mangler); |
1da177e4 LT |
177 | |
178 | if (ret != NF_DROP && ret != NF_STOLEN | |
179 | && (memcmp(&(*pskb)->nh.ipv6h->saddr, &saddr, sizeof(saddr)) | |
180 | || memcmp(&(*pskb)->nh.ipv6h->daddr, &daddr, sizeof(daddr)) | |
82e91ffe | 181 | || (*pskb)->mark != mark |
9123de2c PM |
182 | || (*pskb)->nh.ipv6h->hop_limit != hop_limit)) |
183 | return ip6_route_me_harder(*pskb) == 0 ? ret : NF_DROP; | |
1da177e4 LT |
184 | |
185 | return ret; | |
186 | } | |
187 | ||
188 | static struct nf_hook_ops ip6t_ops[] = { | |
189 | { | |
190 | .hook = ip6t_route_hook, | |
191 | .owner = THIS_MODULE, | |
192 | .pf = PF_INET6, | |
193 | .hooknum = NF_IP6_PRE_ROUTING, | |
194 | .priority = NF_IP6_PRI_MANGLE, | |
195 | }, | |
196 | { | |
197 | .hook = ip6t_local_hook, | |
198 | .owner = THIS_MODULE, | |
199 | .pf = PF_INET6, | |
200 | .hooknum = NF_IP6_LOCAL_IN, | |
201 | .priority = NF_IP6_PRI_MANGLE, | |
202 | }, | |
203 | { | |
204 | .hook = ip6t_route_hook, | |
205 | .owner = THIS_MODULE, | |
206 | .pf = PF_INET6, | |
207 | .hooknum = NF_IP6_FORWARD, | |
208 | .priority = NF_IP6_PRI_MANGLE, | |
209 | }, | |
210 | { | |
211 | .hook = ip6t_local_hook, | |
212 | .owner = THIS_MODULE, | |
213 | .pf = PF_INET6, | |
214 | .hooknum = NF_IP6_LOCAL_OUT, | |
215 | .priority = NF_IP6_PRI_MANGLE, | |
216 | }, | |
217 | { | |
218 | .hook = ip6t_route_hook, | |
219 | .owner = THIS_MODULE, | |
220 | .pf = PF_INET6, | |
221 | .hooknum = NF_IP6_POST_ROUTING, | |
222 | .priority = NF_IP6_PRI_MANGLE, | |
223 | }, | |
224 | }; | |
225 | ||
65b4b4e8 | 226 | static int __init ip6table_mangle_init(void) |
1da177e4 LT |
227 | { |
228 | int ret; | |
229 | ||
230 | /* Register table */ | |
231 | ret = ip6t_register_table(&packet_mangler, &initial_table.repl); | |
232 | if (ret < 0) | |
233 | return ret; | |
234 | ||
235 | /* Register hooks */ | |
964ddaa1 | 236 | ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); |
1da177e4 LT |
237 | if (ret < 0) |
238 | goto cleanup_table; | |
239 | ||
1da177e4 LT |
240 | return ret; |
241 | ||
1da177e4 LT |
242 | cleanup_table: |
243 | ip6t_unregister_table(&packet_mangler); | |
1da177e4 LT |
244 | return ret; |
245 | } | |
246 | ||
65b4b4e8 | 247 | static void __exit ip6table_mangle_fini(void) |
1da177e4 | 248 | { |
964ddaa1 | 249 | nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops)); |
1da177e4 LT |
250 | ip6t_unregister_table(&packet_mangler); |
251 | } | |
252 | ||
65b4b4e8 AM |
253 | module_init(ip6table_mangle_init); |
254 | module_exit(ip6table_mangle_fini); |