Merge branch 'for-2.6.27' of git://git.marvell.com/mv643xx_eth into upstream-fixes
[linux-2.6] / net / ipv6 / netfilter / ip6table_mangle.c
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 #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
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))
23
24 static struct
25 {
26         struct ip6t_replace repl;
27         struct ip6t_standard entries[5];
28         struct ip6t_error term;
29 } initial_table __net_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 = {
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,
41                 },
42                 .underflow = {
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,
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 */
58 };
59
60 static struct xt_table packet_mangler = {
61         .name           = "mangle",
62         .valid_hooks    = MANGLE_VALID_HOOKS,
63         .lock           = __RW_LOCK_UNLOCKED(packet_mangler.lock),
64         .me             = THIS_MODULE,
65         .af             = AF_INET6,
66 };
67
68 /* The work comes in here from netfilter.c. */
69 static unsigned int
70 ip6t_route_hook(unsigned int hook,
71          struct sk_buff *skb,
72          const struct net_device *in,
73          const struct net_device *out,
74          int (*okfn)(struct sk_buff *))
75 {
76         return ip6t_do_table(skb, hook, in, out, init_net.ipv6.ip6table_mangle);
77 }
78
79 static unsigned int
80 ip6t_local_hook(unsigned int hook,
81                    struct sk_buff *skb,
82                    const struct net_device *in,
83                    const struct net_device *out,
84                    int (*okfn)(struct sk_buff *))
85 {
86
87         unsigned int ret;
88         struct in6_addr saddr, daddr;
89         u_int8_t hop_limit;
90         u_int32_t flowlabel, mark;
91
92 #if 0
93         /* root is playing with raw sockets. */
94         if (skb->len < sizeof(struct iphdr)
95             || ip_hdrlen(skb) < sizeof(struct iphdr)) {
96                 if (net_ratelimit())
97                         printk("ip6t_hook: happy cracking.\n");
98                 return NF_ACCEPT;
99         }
100 #endif
101
102         /* save source/dest address, mark, hoplimit, flowlabel, priority,  */
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;
107
108         /* flowlabel and prio (includes version, which shouldn't change either */
109         flowlabel = *((u_int32_t *)ipv6_hdr(skb));
110
111         ret = ip6t_do_table(skb, hook, in, out, init_net.ipv6.ip6table_mangle);
112
113         if (ret != NF_DROP && ret != NF_STOLEN
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;
119
120         return ret;
121 }
122
123 static struct nf_hook_ops ip6t_ops[] __read_mostly = {
124         {
125                 .hook           = ip6t_route_hook,
126                 .owner          = THIS_MODULE,
127                 .pf             = PF_INET6,
128                 .hooknum        = NF_INET_PRE_ROUTING,
129                 .priority       = NF_IP6_PRI_MANGLE,
130         },
131         {
132                 .hook           = ip6t_route_hook,
133                 .owner          = THIS_MODULE,
134                 .pf             = PF_INET6,
135                 .hooknum        = NF_INET_LOCAL_IN,
136                 .priority       = NF_IP6_PRI_MANGLE,
137         },
138         {
139                 .hook           = ip6t_route_hook,
140                 .owner          = THIS_MODULE,
141                 .pf             = PF_INET6,
142                 .hooknum        = NF_INET_FORWARD,
143                 .priority       = NF_IP6_PRI_MANGLE,
144         },
145         {
146                 .hook           = ip6t_local_hook,
147                 .owner          = THIS_MODULE,
148                 .pf             = PF_INET6,
149                 .hooknum        = NF_INET_LOCAL_OUT,
150                 .priority       = NF_IP6_PRI_MANGLE,
151         },
152         {
153                 .hook           = ip6t_route_hook,
154                 .owner          = THIS_MODULE,
155                 .pf             = PF_INET6,
156                 .hooknum        = NF_INET_POST_ROUTING,
157                 .priority       = NF_IP6_PRI_MANGLE,
158         },
159 };
160
161 static int __net_init ip6table_mangle_net_init(struct net *net)
162 {
163         /* Register table */
164         net->ipv6.ip6table_mangle =
165                 ip6t_register_table(net, &packet_mangler, &initial_table.repl);
166         if (IS_ERR(net->ipv6.ip6table_mangle))
167                 return PTR_ERR(net->ipv6.ip6table_mangle);
168         return 0;
169 }
170
171 static void __net_exit ip6table_mangle_net_exit(struct net *net)
172 {
173         ip6t_unregister_table(net->ipv6.ip6table_mangle);
174 }
175
176 static struct pernet_operations ip6table_mangle_net_ops = {
177         .init = ip6table_mangle_net_init,
178         .exit = ip6table_mangle_net_exit,
179 };
180
181 static int __init ip6table_mangle_init(void)
182 {
183         int ret;
184
185         ret = register_pernet_subsys(&ip6table_mangle_net_ops);
186         if (ret < 0)
187                 return ret;
188
189         /* Register hooks */
190         ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
191         if (ret < 0)
192                 goto cleanup_table;
193
194         return ret;
195
196  cleanup_table:
197         unregister_pernet_subsys(&ip6table_mangle_net_ops);
198         return ret;
199 }
200
201 static void __exit ip6table_mangle_fini(void)
202 {
203         nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
204         unregister_pernet_subsys(&ip6table_mangle_net_ops);
205 }
206
207 module_init(ip6table_mangle_init);
208 module_exit(ip6table_mangle_fini);