1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * 'raw' table, which is the very first hooked in at PRE_ROUTING and LOCAL_OUT .
4  *
5  * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@netfilter.org>
6  */
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 #include <linux/module.h>
9 #include <linux/netfilter_ipv4/ip_tables.h>
10 #include <linux/slab.h>
11 #include <net/ip.h>
12 
13 #define RAW_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT))
14 
15 static bool raw_before_defrag __read_mostly;
16 MODULE_PARM_DESC(raw_before_defrag, "Enable raw table before defrag");
17 module_param(raw_before_defrag, bool, 0000);
18 
19 static const struct xt_table packet_raw = {
20 	.name = "raw",
21 	.valid_hooks =  RAW_VALID_HOOKS,
22 	.me = THIS_MODULE,
23 	.af = NFPROTO_IPV4,
24 	.priority = NF_IP_PRI_RAW,
25 };
26 
27 static const struct xt_table packet_raw_before_defrag = {
28 	.name = "raw",
29 	.valid_hooks =  RAW_VALID_HOOKS,
30 	.me = THIS_MODULE,
31 	.af = NFPROTO_IPV4,
32 	.priority = NF_IP_PRI_RAW_BEFORE_DEFRAG,
33 };
34 
35 static struct nf_hook_ops *rawtable_ops __read_mostly;
36 
iptable_raw_table_init(struct net * net)37 static int iptable_raw_table_init(struct net *net)
38 {
39 	struct ipt_replace *repl;
40 	const struct xt_table *table = &packet_raw;
41 	int ret;
42 
43 	if (raw_before_defrag)
44 		table = &packet_raw_before_defrag;
45 
46 	repl = ipt_alloc_initial_table(table);
47 	if (repl == NULL)
48 		return -ENOMEM;
49 	ret = ipt_register_table(net, table, repl, rawtable_ops);
50 	kfree(repl);
51 	return ret;
52 }
53 
iptable_raw_net_pre_exit(struct net * net)54 static void __net_exit iptable_raw_net_pre_exit(struct net *net)
55 {
56 	ipt_unregister_table_pre_exit(net, "raw");
57 }
58 
iptable_raw_net_exit(struct net * net)59 static void __net_exit iptable_raw_net_exit(struct net *net)
60 {
61 	ipt_unregister_table_exit(net, "raw");
62 }
63 
64 static struct pernet_operations iptable_raw_net_ops = {
65 	.pre_exit = iptable_raw_net_pre_exit,
66 	.exit = iptable_raw_net_exit,
67 };
68 
iptable_raw_init(void)69 static int __init iptable_raw_init(void)
70 {
71 	int ret;
72 	const struct xt_table *table = &packet_raw;
73 
74 	if (raw_before_defrag) {
75 		table = &packet_raw_before_defrag;
76 
77 		pr_info("Enabling raw table before defrag\n");
78 	}
79 
80 	ret = xt_register_template(table,
81 				   iptable_raw_table_init);
82 	if (ret < 0)
83 		return ret;
84 
85 	rawtable_ops = xt_hook_ops_alloc(table, ipt_do_table);
86 	if (IS_ERR(rawtable_ops)) {
87 		xt_unregister_template(table);
88 		return PTR_ERR(rawtable_ops);
89 	}
90 
91 	ret = register_pernet_subsys(&iptable_raw_net_ops);
92 	if (ret < 0) {
93 		xt_unregister_template(table);
94 		kfree(rawtable_ops);
95 		return ret;
96 	}
97 
98 	return ret;
99 }
100 
iptable_raw_fini(void)101 static void __exit iptable_raw_fini(void)
102 {
103 	unregister_pernet_subsys(&iptable_raw_net_ops);
104 	kfree(rawtable_ops);
105 	xt_unregister_template(&packet_raw);
106 }
107 
108 module_init(iptable_raw_init);
109 module_exit(iptable_raw_fini);
110 MODULE_LICENSE("GPL");
111