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_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT))
11
12 static struct
13 {
14 struct ipt_replace repl;
15 struct ipt_standard entries[2];
16 struct ipt_error term;
17 } initial_table __net_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_INET_PRE_ROUTING] = 0,
25 [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard)
26 },
27 .underflow = {
28 [NF_INET_PRE_ROUTING] = 0,
29 [NF_INET_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
39 static struct xt_table packet_raw = {
40 .name = "raw",
41 .valid_hooks = RAW_VALID_HOOKS,
42 .lock = __RW_LOCK_UNLOCKED(packet_raw.lock),
43 .me = THIS_MODULE,
44 .af = AF_INET,
45 };
46
47 /* The work comes in here from netfilter.c. */
48 static unsigned int
ipt_hook(unsigned int hook,struct sk_buff * skb,const struct net_device * in,const struct net_device * out,int (* okfn)(struct sk_buff *))49 ipt_hook(unsigned int hook,
50 struct sk_buff *skb,
51 const struct net_device *in,
52 const struct net_device *out,
53 int (*okfn)(struct sk_buff *))
54 {
55 return ipt_do_table(skb, hook, in, out,
56 dev_net(in)->ipv4.iptable_raw);
57 }
58
59 static unsigned int
ipt_local_hook(unsigned int hook,struct sk_buff * skb,const struct net_device * in,const struct net_device * out,int (* okfn)(struct sk_buff *))60 ipt_local_hook(unsigned int hook,
61 struct sk_buff *skb,
62 const struct net_device *in,
63 const struct net_device *out,
64 int (*okfn)(struct sk_buff *))
65 {
66 /* root is playing with raw sockets. */
67 if (skb->len < sizeof(struct iphdr) ||
68 ip_hdrlen(skb) < sizeof(struct iphdr))
69 return NF_ACCEPT;
70 return ipt_do_table(skb, hook, in, out,
71 dev_net(out)->ipv4.iptable_raw);
72 }
73
74 /* 'raw' is the very first table. */
75 static struct nf_hook_ops ipt_ops[] __read_mostly = {
76 {
77 .hook = ipt_hook,
78 .pf = PF_INET,
79 .hooknum = NF_INET_PRE_ROUTING,
80 .priority = NF_IP_PRI_RAW,
81 .owner = THIS_MODULE,
82 },
83 {
84 .hook = ipt_local_hook,
85 .pf = PF_INET,
86 .hooknum = NF_INET_LOCAL_OUT,
87 .priority = NF_IP_PRI_RAW,
88 .owner = THIS_MODULE,
89 },
90 };
91
iptable_raw_net_init(struct net * net)92 static int __net_init iptable_raw_net_init(struct net *net)
93 {
94 /* Register table */
95 net->ipv4.iptable_raw =
96 ipt_register_table(net, &packet_raw, &initial_table.repl);
97 if (IS_ERR(net->ipv4.iptable_raw))
98 return PTR_ERR(net->ipv4.iptable_raw);
99 return 0;
100 }
101
iptable_raw_net_exit(struct net * net)102 static void __net_exit iptable_raw_net_exit(struct net *net)
103 {
104 ipt_unregister_table(net->ipv4.iptable_raw);
105 }
106
107 static struct pernet_operations iptable_raw_net_ops = {
108 .init = iptable_raw_net_init,
109 .exit = iptable_raw_net_exit,
110 };
111
iptable_raw_init(void)112 static int __init iptable_raw_init(void)
113 {
114 int ret;
115
116 ret = register_pernet_subsys(&iptable_raw_net_ops);
117 if (ret < 0)
118 return ret;
119
120 /* Register hooks */
121 ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
122 if (ret < 0)
123 goto cleanup_table;
124
125 return ret;
126
127 cleanup_table:
128 unregister_pernet_subsys(&iptable_raw_net_ops);
129 return ret;
130 }
131
iptable_raw_fini(void)132 static void __exit iptable_raw_fini(void)
133 {
134 nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
135 unregister_pernet_subsys(&iptable_raw_net_ops);
136 }
137
138 module_init(iptable_raw_init);
139 module_exit(iptable_raw_fini);
140 MODULE_LICENSE("GPL");
141