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 * Extended to all five netfilter hooks by Brad Chapman & Harald Welte
13 #include <linux/module.h>
14 #include <linux/netfilter_ipv4/ip_tables.h>
15 #include <linux/netdevice.h>
16 #include <linux/skbuff.h>
18 #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_IP_PRE_ROUTING) | \
26 (1 << NF_IP_LOCAL_IN) | \
27 (1 << NF_IP_FORWARD) | \
28 (1 << NF_IP_LOCAL_OUT) | \
29 (1 << NF_IP_POST_ROUTING))
31 /* Ouch - five different hooks? Maybe this should be a config option..... -- BC */
34 struct ipt_replace repl
;
35 struct ipt_standard entries
[5];
36 struct ipt_error term
;
37 } initial_table __initdata
38 = { { "mangle", MANGLE_VALID_HOOKS
, 6,
39 sizeof(struct ipt_standard
) * 5 + sizeof(struct ipt_error
),
40 { [NF_IP_PRE_ROUTING
] = 0,
41 [NF_IP_LOCAL_IN
] = sizeof(struct ipt_standard
),
42 [NF_IP_FORWARD
] = sizeof(struct ipt_standard
) * 2,
43 [NF_IP_LOCAL_OUT
] = sizeof(struct ipt_standard
) * 3,
44 [NF_IP_POST_ROUTING
] = sizeof(struct ipt_standard
) * 4 },
45 { [NF_IP_PRE_ROUTING
] = 0,
46 [NF_IP_LOCAL_IN
] = sizeof(struct ipt_standard
),
47 [NF_IP_FORWARD
] = sizeof(struct ipt_standard
) * 2,
48 [NF_IP_LOCAL_OUT
] = sizeof(struct ipt_standard
) * 3,
49 [NF_IP_POST_ROUTING
] = sizeof(struct ipt_standard
) * 4 },
53 { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
55 sizeof(struct ipt_entry
),
56 sizeof(struct ipt_standard
),
58 { { { { IPT_ALIGN(sizeof(struct ipt_standard_target
)), "" } }, { } },
61 { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
63 sizeof(struct ipt_entry
),
64 sizeof(struct ipt_standard
),
66 { { { { IPT_ALIGN(sizeof(struct ipt_standard_target
)), "" } }, { } },
69 { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
71 sizeof(struct ipt_entry
),
72 sizeof(struct ipt_standard
),
74 { { { { IPT_ALIGN(sizeof(struct ipt_standard_target
)), "" } }, { } },
77 { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
79 sizeof(struct ipt_entry
),
80 sizeof(struct ipt_standard
),
82 { { { { IPT_ALIGN(sizeof(struct ipt_standard_target
)), "" } }, { } },
85 { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
87 sizeof(struct ipt_entry
),
88 sizeof(struct ipt_standard
),
90 { { { { IPT_ALIGN(sizeof(struct ipt_standard_target
)), "" } }, { } },
94 { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
96 sizeof(struct ipt_entry
),
97 sizeof(struct ipt_error
),
99 { { { { IPT_ALIGN(sizeof(struct ipt_error_target
)), IPT_ERROR_TARGET
} },
106 static struct ipt_table packet_mangler
= {
108 .valid_hooks
= MANGLE_VALID_HOOKS
,
109 .lock
= RW_LOCK_UNLOCKED
,
114 /* The work comes in here from netfilter.c. */
116 ipt_route_hook(unsigned int hook
,
117 struct sk_buff
**pskb
,
118 const struct net_device
*in
,
119 const struct net_device
*out
,
120 int (*okfn
)(struct sk_buff
*))
122 return ipt_do_table(pskb
, hook
, in
, out
, &packet_mangler
);
126 ipt_local_hook(unsigned int hook
,
127 struct sk_buff
**pskb
,
128 const struct net_device
*in
,
129 const struct net_device
*out
,
130 int (*okfn
)(struct sk_buff
*))
137 /* root is playing with raw sockets. */
138 if ((*pskb
)->len
< sizeof(struct iphdr
)
139 || (*pskb
)->nh
.iph
->ihl
* 4 < sizeof(struct iphdr
)) {
141 printk("ipt_hook: happy cracking.\n");
145 /* Save things which could affect route */
146 mark
= (*pskb
)->mark
;
147 saddr
= (*pskb
)->nh
.iph
->saddr
;
148 daddr
= (*pskb
)->nh
.iph
->daddr
;
149 tos
= (*pskb
)->nh
.iph
->tos
;
151 ret
= ipt_do_table(pskb
, hook
, in
, out
, &packet_mangler
);
152 /* Reroute for ANY change. */
153 if (ret
!= NF_DROP
&& ret
!= NF_STOLEN
&& ret
!= NF_QUEUE
154 && ((*pskb
)->nh
.iph
->saddr
!= saddr
155 || (*pskb
)->nh
.iph
->daddr
!= daddr
156 || (*pskb
)->mark
!= mark
157 || (*pskb
)->nh
.iph
->tos
!= tos
))
158 if (ip_route_me_harder(pskb
, RTN_UNSPEC
))
164 static struct nf_hook_ops ipt_ops
[] = {
166 .hook
= ipt_route_hook
,
167 .owner
= THIS_MODULE
,
169 .hooknum
= NF_IP_PRE_ROUTING
,
170 .priority
= NF_IP_PRI_MANGLE
,
173 .hook
= ipt_route_hook
,
174 .owner
= THIS_MODULE
,
176 .hooknum
= NF_IP_LOCAL_IN
,
177 .priority
= NF_IP_PRI_MANGLE
,
180 .hook
= ipt_route_hook
,
181 .owner
= THIS_MODULE
,
183 .hooknum
= NF_IP_FORWARD
,
184 .priority
= NF_IP_PRI_MANGLE
,
187 .hook
= ipt_local_hook
,
188 .owner
= THIS_MODULE
,
190 .hooknum
= NF_IP_LOCAL_OUT
,
191 .priority
= NF_IP_PRI_MANGLE
,
194 .hook
= ipt_route_hook
,
195 .owner
= THIS_MODULE
,
197 .hooknum
= NF_IP_POST_ROUTING
,
198 .priority
= NF_IP_PRI_MANGLE
,
202 static int __init
iptable_mangle_init(void)
207 ret
= ipt_register_table(&packet_mangler
, &initial_table
.repl
);
212 ret
= nf_register_hooks(ipt_ops
, ARRAY_SIZE(ipt_ops
));
219 ipt_unregister_table(&packet_mangler
);
223 static void __exit
iptable_mangle_fini(void)
225 nf_unregister_hooks(ipt_ops
, ARRAY_SIZE(ipt_ops
));
226 ipt_unregister_table(&packet_mangler
);
229 module_init(iptable_mangle_init
);
230 module_exit(iptable_mangle_fini
);