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 | |
b9e69e12 FW |
31 | static int __net_init iptable_mangle_table_init(struct net *net); |
32 | ||
35aad0ff | 33 | static const struct xt_table packet_mangler = { |
1da177e4 LT |
34 | .name = "mangle", |
35 | .valid_hooks = MANGLE_VALID_HOOKS, | |
1da177e4 | 36 | .me = THIS_MODULE, |
f88e6a8a | 37 | .af = NFPROTO_IPV4, |
2b95efe7 | 38 | .priority = NF_IP_PRI_MANGLE, |
b9e69e12 | 39 | .table_init = iptable_mangle_table_init, |
1da177e4 LT |
40 | }; |
41 | ||
1da177e4 | 42 | static unsigned int |
1c491ba2 | 43 | ipt_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state) |
1da177e4 LT |
44 | { |
45 | unsigned int ret; | |
eddc9ec5 | 46 | const struct iphdr *iph; |
1da177e4 | 47 | u_int8_t tos; |
6a19d614 | 48 | __be32 saddr, daddr; |
82e91ffe | 49 | u_int32_t mark; |
c9e1673a | 50 | int err; |
1da177e4 LT |
51 | |
52 | /* root is playing with raw sockets. */ | |
3666ed1c JP |
53 | if (skb->len < sizeof(struct iphdr) || |
54 | ip_hdrlen(skb) < sizeof(struct iphdr)) | |
1da177e4 | 55 | return NF_ACCEPT; |
1da177e4 LT |
56 | |
57 | /* Save things which could affect route */ | |
3db05fea HX |
58 | mark = skb->mark; |
59 | iph = ip_hdr(skb); | |
eddc9ec5 ACM |
60 | saddr = iph->saddr; |
61 | daddr = iph->daddr; | |
62 | tos = iph->tos; | |
1da177e4 | 63 | |
6cb8ff3f | 64 | ret = ipt_do_table(skb, state, state->net->ipv4.iptable_mangle); |
1da177e4 | 65 | /* Reroute for ANY change. */ |
28a51ba5 | 66 | if (ret != NF_DROP && ret != NF_STOLEN) { |
3db05fea | 67 | iph = ip_hdr(skb); |
eddc9ec5 ACM |
68 | |
69 | if (iph->saddr != saddr || | |
70 | iph->daddr != daddr || | |
3db05fea | 71 | skb->mark != mark || |
c9e1673a | 72 | iph->tos != tos) { |
e45f5066 | 73 | err = ip_route_me_harder(state->net, skb, RTN_UNSPEC); |
c9e1673a PM |
74 | if (err < 0) |
75 | ret = NF_DROP_ERR(err); | |
76 | } | |
eddc9ec5 | 77 | } |
1da177e4 LT |
78 | |
79 | return ret; | |
80 | } | |
81 | ||
737535c5 JE |
82 | /* The work comes in here from netfilter.c. */ |
83 | static unsigned int | |
06198b34 | 84 | iptable_mangle_hook(void *priv, |
737535c5 | 85 | struct sk_buff *skb, |
238e54c9 | 86 | const struct nf_hook_state *state) |
737535c5 | 87 | { |
6cb8ff3f | 88 | if (state->hook == NF_INET_LOCAL_OUT) |
1c491ba2 | 89 | return ipt_mangle_out(skb, state); |
6cb8ff3f | 90 | return ipt_do_table(skb, state, state->net->ipv4.iptable_mangle); |
737535c5 JE |
91 | } |
92 | ||
2b95efe7 | 93 | static struct nf_hook_ops *mangle_ops __read_mostly; |
b9e69e12 | 94 | static int __net_init iptable_mangle_table_init(struct net *net) |
9335f047 | 95 | { |
e3eaa991 | 96 | struct ipt_replace *repl; |
a67dd266 | 97 | int ret; |
e3eaa991 | 98 | |
b9e69e12 FW |
99 | if (net->ipv4.iptable_mangle) |
100 | return 0; | |
101 | ||
e3eaa991 JE |
102 | repl = ipt_alloc_initial_table(&packet_mangler); |
103 | if (repl == NULL) | |
104 | return -ENOMEM; | |
a67dd266 FW |
105 | ret = ipt_register_table(net, &packet_mangler, repl, mangle_ops, |
106 | &net->ipv4.iptable_mangle); | |
e3eaa991 | 107 | kfree(repl); |
a67dd266 | 108 | return ret; |
9335f047 AD |
109 | } |
110 | ||
111 | static void __net_exit iptable_mangle_net_exit(struct net *net) | |
112 | { | |
b9e69e12 FW |
113 | if (!net->ipv4.iptable_mangle) |
114 | return; | |
a67dd266 | 115 | ipt_unregister_table(net, net->ipv4.iptable_mangle, mangle_ops); |
b9e69e12 | 116 | net->ipv4.iptable_mangle = NULL; |
9335f047 AD |
117 | } |
118 | ||
119 | static struct pernet_operations iptable_mangle_net_ops = { | |
9335f047 AD |
120 | .exit = iptable_mangle_net_exit, |
121 | }; | |
122 | ||
65b4b4e8 | 123 | static int __init iptable_mangle_init(void) |
1da177e4 LT |
124 | { |
125 | int ret; | |
126 | ||
b9e69e12 FW |
127 | mangle_ops = xt_hook_ops_alloc(&packet_mangler, iptable_mangle_hook); |
128 | if (IS_ERR(mangle_ops)) { | |
129 | ret = PTR_ERR(mangle_ops); | |
130 | return ret; | |
131 | } | |
132 | ||
9335f047 | 133 | ret = register_pernet_subsys(&iptable_mangle_net_ops); |
b9e69e12 FW |
134 | if (ret < 0) { |
135 | kfree(mangle_ops); | |
9335f047 | 136 | return ret; |
b9e69e12 | 137 | } |
1da177e4 | 138 | |
b9e69e12 FW |
139 | ret = iptable_mangle_table_init(&init_net); |
140 | if (ret) { | |
90efbed1 | 141 | unregister_pernet_subsys(&iptable_mangle_net_ops); |
b9e69e12 | 142 | kfree(mangle_ops); |
2b95efe7 | 143 | } |
1da177e4 | 144 | |
1da177e4 | 145 | return ret; |
1da177e4 LT |
146 | } |
147 | ||
65b4b4e8 | 148 | static void __exit iptable_mangle_fini(void) |
1da177e4 | 149 | { |
9335f047 | 150 | unregister_pernet_subsys(&iptable_mangle_net_ops); |
b9e69e12 | 151 | kfree(mangle_ops); |
1da177e4 LT |
152 | } |
153 | ||
65b4b4e8 AM |
154 | module_init(iptable_mangle_init); |
155 | module_exit(iptable_mangle_fini); |