Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x. | |
3 | * | |
4 | * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling | |
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 | 10 | */ |
1da177e4 LT |
11 | #include <linux/module.h> |
12 | #include <linux/netfilter_ipv4/ip_tables.h> | |
13 | #include <linux/netdevice.h> | |
14 | #include <linux/skbuff.h> | |
15 | #include <net/sock.h> | |
16 | #include <net/route.h> | |
17 | #include <linux/ip.h> | |
c9bdd4b5 | 18 | #include <net/ip.h> |
1da177e4 LT |
19 | |
20 | MODULE_LICENSE("GPL"); | |
21 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
22 | MODULE_DESCRIPTION("iptables mangle table"); | |
23 | ||
6e23ae2a PM |
24 | #define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \ |
25 | (1 << NF_INET_LOCAL_IN) | \ | |
26 | (1 << NF_INET_FORWARD) | \ | |
27 | (1 << NF_INET_LOCAL_OUT) | \ | |
28 | (1 << NF_INET_POST_ROUTING)) | |
1da177e4 LT |
29 | |
30 | /* Ouch - five different hooks? Maybe this should be a config option..... -- BC */ | |
35aad0ff | 31 | static const struct |
1da177e4 LT |
32 | { |
33 | struct ipt_replace repl; | |
34 | struct ipt_standard entries[5]; | |
35 | struct ipt_error term; | |
9335f047 | 36 | } initial_table __net_initdata = { |
3c2ad469 PM |
37 | .repl = { |
38 | .name = "mangle", | |
39 | .valid_hooks = MANGLE_VALID_HOOKS, | |
40 | .num_entries = 6, | |
41 | .size = sizeof(struct ipt_standard) * 5 + sizeof(struct ipt_error), | |
42 | .hook_entry = { | |
6e23ae2a PM |
43 | [NF_INET_PRE_ROUTING] = 0, |
44 | [NF_INET_LOCAL_IN] = sizeof(struct ipt_standard), | |
45 | [NF_INET_FORWARD] = sizeof(struct ipt_standard) * 2, | |
46 | [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 3, | |
47 | [NF_INET_POST_ROUTING] = sizeof(struct ipt_standard) * 4, | |
3c2ad469 PM |
48 | }, |
49 | .underflow = { | |
6e23ae2a PM |
50 | [NF_INET_PRE_ROUTING] = 0, |
51 | [NF_INET_LOCAL_IN] = sizeof(struct ipt_standard), | |
52 | [NF_INET_FORWARD] = sizeof(struct ipt_standard) * 2, | |
53 | [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 3, | |
54 | [NF_INET_POST_ROUTING] = sizeof(struct ipt_standard) * 4, | |
3c2ad469 PM |
55 | }, |
56 | }, | |
57 | .entries = { | |
58 | IPT_STANDARD_INIT(NF_ACCEPT), /* PRE_ROUTING */ | |
59 | IPT_STANDARD_INIT(NF_ACCEPT), /* LOCAL_IN */ | |
60 | IPT_STANDARD_INIT(NF_ACCEPT), /* FORWARD */ | |
61 | IPT_STANDARD_INIT(NF_ACCEPT), /* LOCAL_OUT */ | |
62 | IPT_STANDARD_INIT(NF_ACCEPT), /* POST_ROUTING */ | |
63 | }, | |
64 | .term = IPT_ERROR_INIT, /* ERROR */ | |
1da177e4 LT |
65 | }; |
66 | ||
35aad0ff | 67 | static const struct xt_table packet_mangler = { |
1da177e4 LT |
68 | .name = "mangle", |
69 | .valid_hooks = MANGLE_VALID_HOOKS, | |
1da177e4 | 70 | .me = THIS_MODULE, |
f88e6a8a | 71 | .af = NFPROTO_IPV4, |
1da177e4 LT |
72 | }; |
73 | ||
74 | /* The work comes in here from netfilter.c. */ | |
75 | static unsigned int | |
666953df AD |
76 | ipt_pre_routing_hook(unsigned int hook, |
77 | struct sk_buff *skb, | |
78 | const struct net_device *in, | |
79 | const struct net_device *out, | |
80 | int (*okfn)(struct sk_buff *)) | |
81 | { | |
82 | return ipt_do_table(skb, hook, in, out, | |
48dc7865 | 83 | dev_net(in)->ipv4.iptable_mangle); |
666953df AD |
84 | } |
85 | ||
86 | static unsigned int | |
87 | ipt_post_routing_hook(unsigned int hook, | |
88 | struct sk_buff *skb, | |
89 | const struct net_device *in, | |
90 | const struct net_device *out, | |
91 | int (*okfn)(struct sk_buff *)) | |
92 | { | |
93 | return ipt_do_table(skb, hook, in, out, | |
48dc7865 | 94 | dev_net(out)->ipv4.iptable_mangle); |
666953df AD |
95 | } |
96 | ||
97 | static unsigned int | |
98 | ipt_local_in_hook(unsigned int hook, | |
99 | struct sk_buff *skb, | |
100 | const struct net_device *in, | |
101 | const struct net_device *out, | |
102 | int (*okfn)(struct sk_buff *)) | |
103 | { | |
104 | return ipt_do_table(skb, hook, in, out, | |
48dc7865 | 105 | dev_net(in)->ipv4.iptable_mangle); |
666953df AD |
106 | } |
107 | ||
108 | static unsigned int | |
109 | ipt_forward_hook(unsigned int hook, | |
3db05fea | 110 | struct sk_buff *skb, |
1da177e4 LT |
111 | const struct net_device *in, |
112 | const struct net_device *out, | |
113 | int (*okfn)(struct sk_buff *)) | |
114 | { | |
666953df | 115 | return ipt_do_table(skb, hook, in, out, |
48dc7865 | 116 | dev_net(in)->ipv4.iptable_mangle); |
1da177e4 LT |
117 | } |
118 | ||
119 | static unsigned int | |
120 | ipt_local_hook(unsigned int hook, | |
3db05fea | 121 | struct sk_buff *skb, |
1da177e4 LT |
122 | const struct net_device *in, |
123 | const struct net_device *out, | |
124 | int (*okfn)(struct sk_buff *)) | |
125 | { | |
126 | unsigned int ret; | |
eddc9ec5 | 127 | const struct iphdr *iph; |
1da177e4 | 128 | u_int8_t tos; |
6a19d614 | 129 | __be32 saddr, daddr; |
82e91ffe | 130 | u_int32_t mark; |
1da177e4 LT |
131 | |
132 | /* root is playing with raw sockets. */ | |
3db05fea | 133 | if (skb->len < sizeof(struct iphdr) |
88843104 | 134 | || ip_hdrlen(skb) < sizeof(struct iphdr)) |
1da177e4 | 135 | return NF_ACCEPT; |
1da177e4 LT |
136 | |
137 | /* Save things which could affect route */ | |
3db05fea HX |
138 | mark = skb->mark; |
139 | iph = ip_hdr(skb); | |
eddc9ec5 ACM |
140 | saddr = iph->saddr; |
141 | daddr = iph->daddr; | |
142 | tos = iph->tos; | |
1da177e4 | 143 | |
666953df | 144 | ret = ipt_do_table(skb, hook, in, out, |
48dc7865 | 145 | dev_net(out)->ipv4.iptable_mangle); |
1da177e4 | 146 | /* Reroute for ANY change. */ |
eddc9ec5 | 147 | if (ret != NF_DROP && ret != NF_STOLEN && ret != NF_QUEUE) { |
3db05fea | 148 | iph = ip_hdr(skb); |
eddc9ec5 ACM |
149 | |
150 | if (iph->saddr != saddr || | |
151 | iph->daddr != daddr || | |
3db05fea | 152 | skb->mark != mark || |
eddc9ec5 | 153 | iph->tos != tos) |
3db05fea | 154 | if (ip_route_me_harder(skb, RTN_UNSPEC)) |
eddc9ec5 ACM |
155 | ret = NF_DROP; |
156 | } | |
1da177e4 LT |
157 | |
158 | return ret; | |
159 | } | |
160 | ||
1999414a | 161 | static struct nf_hook_ops ipt_ops[] __read_mostly = { |
1da177e4 | 162 | { |
666953df | 163 | .hook = ipt_pre_routing_hook, |
1da177e4 | 164 | .owner = THIS_MODULE, |
24c232d8 | 165 | .pf = NFPROTO_IPV4, |
6e23ae2a | 166 | .hooknum = NF_INET_PRE_ROUTING, |
1da177e4 LT |
167 | .priority = NF_IP_PRI_MANGLE, |
168 | }, | |
169 | { | |
666953df | 170 | .hook = ipt_local_in_hook, |
1da177e4 | 171 | .owner = THIS_MODULE, |
24c232d8 | 172 | .pf = NFPROTO_IPV4, |
6e23ae2a | 173 | .hooknum = NF_INET_LOCAL_IN, |
1da177e4 LT |
174 | .priority = NF_IP_PRI_MANGLE, |
175 | }, | |
176 | { | |
666953df | 177 | .hook = ipt_forward_hook, |
1da177e4 | 178 | .owner = THIS_MODULE, |
24c232d8 | 179 | .pf = NFPROTO_IPV4, |
6e23ae2a | 180 | .hooknum = NF_INET_FORWARD, |
1da177e4 LT |
181 | .priority = NF_IP_PRI_MANGLE, |
182 | }, | |
183 | { | |
184 | .hook = ipt_local_hook, | |
185 | .owner = THIS_MODULE, | |
24c232d8 | 186 | .pf = NFPROTO_IPV4, |
6e23ae2a | 187 | .hooknum = NF_INET_LOCAL_OUT, |
1da177e4 LT |
188 | .priority = NF_IP_PRI_MANGLE, |
189 | }, | |
190 | { | |
666953df | 191 | .hook = ipt_post_routing_hook, |
1da177e4 | 192 | .owner = THIS_MODULE, |
24c232d8 | 193 | .pf = NFPROTO_IPV4, |
6e23ae2a | 194 | .hooknum = NF_INET_POST_ROUTING, |
1da177e4 LT |
195 | .priority = NF_IP_PRI_MANGLE, |
196 | }, | |
197 | }; | |
198 | ||
9335f047 AD |
199 | static int __net_init iptable_mangle_net_init(struct net *net) |
200 | { | |
201 | /* Register table */ | |
202 | net->ipv4.iptable_mangle = | |
203 | ipt_register_table(net, &packet_mangler, &initial_table.repl); | |
204 | if (IS_ERR(net->ipv4.iptable_mangle)) | |
205 | return PTR_ERR(net->ipv4.iptable_mangle); | |
206 | return 0; | |
207 | } | |
208 | ||
209 | static void __net_exit iptable_mangle_net_exit(struct net *net) | |
210 | { | |
211 | ipt_unregister_table(net->ipv4.iptable_mangle); | |
212 | } | |
213 | ||
214 | static struct pernet_operations iptable_mangle_net_ops = { | |
215 | .init = iptable_mangle_net_init, | |
216 | .exit = iptable_mangle_net_exit, | |
217 | }; | |
218 | ||
65b4b4e8 | 219 | static int __init iptable_mangle_init(void) |
1da177e4 LT |
220 | { |
221 | int ret; | |
222 | ||
9335f047 AD |
223 | ret = register_pernet_subsys(&iptable_mangle_net_ops); |
224 | if (ret < 0) | |
225 | return ret; | |
1da177e4 LT |
226 | |
227 | /* Register hooks */ | |
964ddaa1 | 228 | ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); |
1da177e4 LT |
229 | if (ret < 0) |
230 | goto cleanup_table; | |
231 | ||
1da177e4 LT |
232 | return ret; |
233 | ||
1da177e4 | 234 | cleanup_table: |
9335f047 | 235 | unregister_pernet_subsys(&iptable_mangle_net_ops); |
1da177e4 LT |
236 | return ret; |
237 | } | |
238 | ||
65b4b4e8 | 239 | static void __exit iptable_mangle_fini(void) |
1da177e4 | 240 | { |
964ddaa1 | 241 | nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); |
9335f047 | 242 | unregister_pernet_subsys(&iptable_mangle_net_ops); |
1da177e4 LT |
243 | } |
244 | ||
65b4b4e8 AM |
245 | module_init(iptable_mangle_init); |
246 | module_exit(iptable_mangle_fini); |