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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> | |
5a0e3ad6 | 15 | #include <linux/slab.h> |
1da177e4 LT |
16 | #include <net/sock.h> |
17 | #include <net/route.h> | |
18 | #include <linux/ip.h> | |
c9bdd4b5 | 19 | #include <net/ip.h> |
1da177e4 LT |
20 | |
21 | MODULE_LICENSE("GPL"); | |
22 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
23 | MODULE_DESCRIPTION("iptables mangle table"); | |
24 | ||
6e23ae2a PM |
25 | #define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \ |
26 | (1 << NF_INET_LOCAL_IN) | \ | |
27 | (1 << NF_INET_FORWARD) | \ | |
28 | (1 << NF_INET_LOCAL_OUT) | \ | |
29 | (1 << NF_INET_POST_ROUTING)) | |
1da177e4 | 30 | |
35aad0ff | 31 | static const struct xt_table packet_mangler = { |
1da177e4 LT |
32 | .name = "mangle", |
33 | .valid_hooks = MANGLE_VALID_HOOKS, | |
1da177e4 | 34 | .me = THIS_MODULE, |
f88e6a8a | 35 | .af = NFPROTO_IPV4, |
2b95efe7 | 36 | .priority = NF_IP_PRI_MANGLE, |
1da177e4 LT |
37 | }; |
38 | ||
1da177e4 | 39 | static unsigned int |
fa96a0e2 | 40 | ipt_mangle_out(struct sk_buff *skb, const struct net_device *out) |
1da177e4 LT |
41 | { |
42 | unsigned int ret; | |
eddc9ec5 | 43 | const struct iphdr *iph; |
1da177e4 | 44 | u_int8_t tos; |
6a19d614 | 45 | __be32 saddr, daddr; |
82e91ffe | 46 | u_int32_t mark; |
1da177e4 LT |
47 | |
48 | /* root is playing with raw sockets. */ | |
3666ed1c JP |
49 | if (skb->len < sizeof(struct iphdr) || |
50 | ip_hdrlen(skb) < sizeof(struct iphdr)) | |
1da177e4 | 51 | return NF_ACCEPT; |
1da177e4 LT |
52 | |
53 | /* Save things which could affect route */ | |
3db05fea HX |
54 | mark = skb->mark; |
55 | iph = ip_hdr(skb); | |
eddc9ec5 ACM |
56 | saddr = iph->saddr; |
57 | daddr = iph->daddr; | |
58 | tos = iph->tos; | |
1da177e4 | 59 | |
fa96a0e2 | 60 | ret = ipt_do_table(skb, NF_INET_LOCAL_OUT, NULL, out, |
48dc7865 | 61 | dev_net(out)->ipv4.iptable_mangle); |
1da177e4 | 62 | /* Reroute for ANY change. */ |
eddc9ec5 | 63 | if (ret != NF_DROP && ret != NF_STOLEN && ret != NF_QUEUE) { |
3db05fea | 64 | iph = ip_hdr(skb); |
eddc9ec5 ACM |
65 | |
66 | if (iph->saddr != saddr || | |
67 | iph->daddr != daddr || | |
3db05fea | 68 | skb->mark != mark || |
eddc9ec5 | 69 | iph->tos != tos) |
3db05fea | 70 | if (ip_route_me_harder(skb, RTN_UNSPEC)) |
eddc9ec5 ACM |
71 | ret = NF_DROP; |
72 | } | |
1da177e4 LT |
73 | |
74 | return ret; | |
75 | } | |
76 | ||
737535c5 JE |
77 | /* The work comes in here from netfilter.c. */ |
78 | static unsigned int | |
79 | iptable_mangle_hook(unsigned int hook, | |
80 | struct sk_buff *skb, | |
81 | const struct net_device *in, | |
82 | const struct net_device *out, | |
83 | int (*okfn)(struct sk_buff *)) | |
84 | { | |
85 | if (hook == NF_INET_LOCAL_OUT) | |
fa96a0e2 | 86 | return ipt_mangle_out(skb, out); |
b2907e50 AD |
87 | if (hook == NF_INET_POST_ROUTING) |
88 | return ipt_do_table(skb, hook, in, out, | |
89 | dev_net(out)->ipv4.iptable_mangle); | |
737535c5 JE |
90 | /* PREROUTING/INPUT/FORWARD: */ |
91 | return ipt_do_table(skb, hook, in, out, | |
92 | dev_net(in)->ipv4.iptable_mangle); | |
93 | } | |
94 | ||
2b95efe7 | 95 | static struct nf_hook_ops *mangle_ops __read_mostly; |
1da177e4 | 96 | |
9335f047 AD |
97 | static int __net_init iptable_mangle_net_init(struct net *net) |
98 | { | |
e3eaa991 JE |
99 | struct ipt_replace *repl; |
100 | ||
101 | repl = ipt_alloc_initial_table(&packet_mangler); | |
102 | if (repl == NULL) | |
103 | return -ENOMEM; | |
9335f047 | 104 | net->ipv4.iptable_mangle = |
e3eaa991 JE |
105 | ipt_register_table(net, &packet_mangler, repl); |
106 | kfree(repl); | |
9335f047 AD |
107 | if (IS_ERR(net->ipv4.iptable_mangle)) |
108 | return PTR_ERR(net->ipv4.iptable_mangle); | |
109 | return 0; | |
110 | } | |
111 | ||
112 | static void __net_exit iptable_mangle_net_exit(struct net *net) | |
113 | { | |
f54e9367 | 114 | ipt_unregister_table(net, net->ipv4.iptable_mangle); |
9335f047 AD |
115 | } |
116 | ||
117 | static struct pernet_operations iptable_mangle_net_ops = { | |
118 | .init = iptable_mangle_net_init, | |
119 | .exit = iptable_mangle_net_exit, | |
120 | }; | |
121 | ||
65b4b4e8 | 122 | static int __init iptable_mangle_init(void) |
1da177e4 LT |
123 | { |
124 | int ret; | |
125 | ||
9335f047 AD |
126 | ret = register_pernet_subsys(&iptable_mangle_net_ops); |
127 | if (ret < 0) | |
128 | return ret; | |
1da177e4 LT |
129 | |
130 | /* Register hooks */ | |
2b95efe7 JE |
131 | mangle_ops = xt_hook_link(&packet_mangler, iptable_mangle_hook); |
132 | if (IS_ERR(mangle_ops)) { | |
133 | ret = PTR_ERR(mangle_ops); | |
1da177e4 | 134 | goto cleanup_table; |
2b95efe7 | 135 | } |
1da177e4 | 136 | |
1da177e4 LT |
137 | return ret; |
138 | ||
1da177e4 | 139 | cleanup_table: |
9335f047 | 140 | unregister_pernet_subsys(&iptable_mangle_net_ops); |
1da177e4 LT |
141 | return ret; |
142 | } | |
143 | ||
65b4b4e8 | 144 | static void __exit iptable_mangle_fini(void) |
1da177e4 | 145 | { |
2b95efe7 | 146 | xt_hook_unlink(&packet_mangler, mangle_ops); |
9335f047 | 147 | unregister_pernet_subsys(&iptable_mangle_net_ops); |
1da177e4 LT |
148 | } |
149 | ||
65b4b4e8 AM |
150 | module_init(iptable_mangle_init); |
151 | module_exit(iptable_mangle_fini); |