2 * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
4 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
5 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
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.
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 <linux/slab.h>
17 #include <net/route.h>
21 MODULE_LICENSE("GPL");
22 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
23 MODULE_DESCRIPTION("iptables mangle table");
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))
31 static int __net_init
iptable_mangle_table_init(struct net
*net
);
33 static const struct xt_table packet_mangler
= {
35 .valid_hooks
= MANGLE_VALID_HOOKS
,
38 .priority
= NF_IP_PRI_MANGLE
,
39 .table_init
= iptable_mangle_table_init
,
43 ipt_mangle_out(struct sk_buff
*skb
, const struct nf_hook_state
*state
)
46 const struct iphdr
*iph
;
52 /* root is playing with raw sockets. */
53 if (skb
->len
< sizeof(struct iphdr
) ||
54 ip_hdrlen(skb
) < sizeof(struct iphdr
))
57 /* Save things which could affect route */
64 ret
= ipt_do_table(skb
, state
, state
->net
->ipv4
.iptable_mangle
);
65 /* Reroute for ANY change. */
66 if (ret
!= NF_DROP
&& ret
!= NF_STOLEN
) {
69 if (iph
->saddr
!= saddr
||
70 iph
->daddr
!= daddr
||
73 err
= ip_route_me_harder(state
->net
, skb
, RTN_UNSPEC
);
75 ret
= NF_DROP_ERR(err
);
82 /* The work comes in here from netfilter.c. */
84 iptable_mangle_hook(void *priv
,
86 const struct nf_hook_state
*state
)
88 if (state
->hook
== NF_INET_LOCAL_OUT
)
89 return ipt_mangle_out(skb
, state
);
90 return ipt_do_table(skb
, state
, state
->net
->ipv4
.iptable_mangle
);
93 static struct nf_hook_ops
*mangle_ops __read_mostly
;
94 static int __net_init
iptable_mangle_table_init(struct net
*net
)
96 struct ipt_replace
*repl
;
99 if (net
->ipv4
.iptable_mangle
)
102 repl
= ipt_alloc_initial_table(&packet_mangler
);
105 ret
= ipt_register_table(net
, &packet_mangler
, repl
, mangle_ops
,
106 &net
->ipv4
.iptable_mangle
);
111 static void __net_exit
iptable_mangle_net_exit(struct net
*net
)
113 if (!net
->ipv4
.iptable_mangle
)
115 ipt_unregister_table(net
, net
->ipv4
.iptable_mangle
, mangle_ops
);
116 net
->ipv4
.iptable_mangle
= NULL
;
119 static struct pernet_operations iptable_mangle_net_ops
= {
120 .exit
= iptable_mangle_net_exit
,
123 static int __init
iptable_mangle_init(void)
127 mangle_ops
= xt_hook_ops_alloc(&packet_mangler
, iptable_mangle_hook
);
128 if (IS_ERR(mangle_ops
)) {
129 ret
= PTR_ERR(mangle_ops
);
133 ret
= register_pernet_subsys(&iptable_mangle_net_ops
);
139 ret
= iptable_mangle_table_init(&init_net
);
141 unregister_pernet_subsys(&iptable_mangle_net_ops
);
148 static void __exit
iptable_mangle_fini(void)
150 unregister_pernet_subsys(&iptable_mangle_net_ops
);
154 module_init(iptable_mangle_init
);
155 module_exit(iptable_mangle_fini
);