1/*
2 * 'raw' table, which is the very first hooked in at PRE_ROUTING and LOCAL_OUT .
3 *
4 * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
5 */
6#include <linux/module.h>
7#include <linux/netfilter_ipv4/ip_tables.h>
8#include <net/ip.h>
9
10#define RAW_VALID_HOOKS ((1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_OUT))
11
12static struct
13{
14	struct ipt_replace repl;
15	struct ipt_standard entries[2];
16	struct ipt_error term;
17} initial_table __initdata = {
18	.repl = {
19		.name = "raw",
20		.valid_hooks = RAW_VALID_HOOKS,
21		.num_entries = 3,
22		.size = sizeof(struct ipt_standard) * 2 + sizeof(struct ipt_error),
23		.hook_entry = {
24			[NF_IP_PRE_ROUTING] = 0,
25			[NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard)
26		},
27		.underflow = {
28			[NF_IP_PRE_ROUTING] = 0,
29			[NF_IP_LOCAL_OUT]  = sizeof(struct ipt_standard)
30		},
31	},
32	.entries = {
33		IPT_STANDARD_INIT(NF_ACCEPT),	/* PRE_ROUTING */
34		IPT_STANDARD_INIT(NF_ACCEPT),	/* LOCAL_OUT */
35	},
36	.term = IPT_ERROR_INIT,			/* ERROR */
37};
38
39static struct xt_table packet_raw = {
40	.name = "raw",
41	.valid_hooks =  RAW_VALID_HOOKS,
42	.lock = RW_LOCK_UNLOCKED,
43	.me = THIS_MODULE,
44	.af = AF_INET,
45};
46
47/* The work comes in here from netfilter.c. */
48static unsigned int
49ipt_hook(unsigned int hook,
50	 struct sk_buff **pskb,
51	 const struct net_device *in,
52	 const struct net_device *out,
53	 int (*okfn)(struct sk_buff *))
54{
55	return ipt_do_table(pskb, hook, in, out, &packet_raw);
56}
57
58static unsigned int
59ipt_local_hook(unsigned int hook,
60	       struct sk_buff **pskb,
61	       const struct net_device *in,
62	       const struct net_device *out,
63	       int (*okfn)(struct sk_buff *))
64{
65	/* root is playing with raw sockets. */
66	if ((*pskb)->len < sizeof(struct iphdr) ||
67	    ip_hdrlen(*pskb) < sizeof(struct iphdr)) {
68		if (net_ratelimit())
69			printk("iptable_raw: ignoring short SOCK_RAW"
70			       "packet.\n");
71		return NF_ACCEPT;
72	}
73	return ipt_do_table(pskb, hook, in, out, &packet_raw);
74}
75
76/* 'raw' is the very first table. */
77static struct nf_hook_ops ipt_ops[] = {
78	{
79		.hook = ipt_hook,
80		.pf = PF_INET,
81		.hooknum = NF_IP_PRE_ROUTING,
82		.priority = NF_IP_PRI_RAW,
83		.owner = THIS_MODULE,
84	},
85	{
86		.hook = ipt_local_hook,
87		.pf = PF_INET,
88		.hooknum = NF_IP_LOCAL_OUT,
89		.priority = NF_IP_PRI_RAW,
90		.owner = THIS_MODULE,
91	},
92};
93
94static int __init iptable_raw_init(void)
95{
96	int ret;
97
98	/* Register table */
99	ret = ipt_register_table(&packet_raw, &initial_table.repl);
100	if (ret < 0)
101		return ret;
102
103	/* Register hooks */
104	ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
105	if (ret < 0)
106		goto cleanup_table;
107
108	return ret;
109
110 cleanup_table:
111	ipt_unregister_table(&packet_raw);
112	return ret;
113}
114
115static void __exit iptable_raw_fini(void)
116{
117	nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
118	ipt_unregister_table(&packet_raw);
119}
120
121module_init(iptable_raw_init);
122module_exit(iptable_raw_fini);
123MODULE_LICENSE("GPL");
124