1 /*
2 * "TEE" target extension for Xtables
3 * Copyright © Sebastian Claßen, 2007
4 * Jan Engelhardt, 2007-2010
5 *
6 * based on ipt_ROUTE.c from Cédric de Launois
7 * <delaunois@info.ucl.be>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * version 2 or later, as published by the Free Software Foundation.
12 */
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/route.h>
16 #include <linux/netfilter/x_tables.h>
17 #include <net/route.h>
18 #include <net/netfilter/ipv4/nf_dup_ipv4.h>
19 #include <net/netfilter/ipv6/nf_dup_ipv6.h>
20 #include <linux/netfilter/xt_TEE.h>
21
22 struct xt_tee_priv {
23 struct list_head list;
24 struct xt_tee_tginfo *tginfo;
25 int oif;
26 };
27
28 static const union nf_inet_addr tee_zero_address;
29
30 static unsigned int
tee_tg4(struct sk_buff * skb,const struct xt_action_param * par)31 tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
32 {
33 const struct xt_tee_tginfo *info = par->targinfo;
34 int oif = info->priv ? info->priv->oif : 0;
35
36 nf_dup_ipv4(xt_net(par), skb, xt_hooknum(par), &info->gw.in, oif);
37
38 return XT_CONTINUE;
39 }
40
41 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
42 static unsigned int
tee_tg6(struct sk_buff * skb,const struct xt_action_param * par)43 tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
44 {
45 const struct xt_tee_tginfo *info = par->targinfo;
46 int oif = info->priv ? info->priv->oif : 0;
47
48 nf_dup_ipv6(xt_net(par), skb, xt_hooknum(par), &info->gw.in6, oif);
49
50 return XT_CONTINUE;
51 }
52 #endif
53
54 static DEFINE_MUTEX(priv_list_mutex);
55 static LIST_HEAD(priv_list);
56
tee_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)57 static int tee_netdev_event(struct notifier_block *this, unsigned long event,
58 void *ptr)
59 {
60 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
61 struct xt_tee_priv *priv;
62
63 mutex_lock(&priv_list_mutex);
64 list_for_each_entry(priv, &priv_list, list) {
65 switch (event) {
66 case NETDEV_REGISTER:
67 if (!strcmp(dev->name, priv->tginfo->oif))
68 priv->oif = dev->ifindex;
69 break;
70 case NETDEV_UNREGISTER:
71 if (dev->ifindex == priv->oif)
72 priv->oif = -1;
73 break;
74 case NETDEV_CHANGENAME:
75 if (!strcmp(dev->name, priv->tginfo->oif))
76 priv->oif = dev->ifindex;
77 else if (dev->ifindex == priv->oif)
78 priv->oif = -1;
79 break;
80 }
81 }
82 mutex_unlock(&priv_list_mutex);
83
84 return NOTIFY_DONE;
85 }
86
tee_tg_check(const struct xt_tgchk_param * par)87 static int tee_tg_check(const struct xt_tgchk_param *par)
88 {
89 struct xt_tee_tginfo *info = par->targinfo;
90 struct xt_tee_priv *priv;
91
92 /* 0.0.0.0 and :: not allowed */
93 if (memcmp(&info->gw, &tee_zero_address,
94 sizeof(tee_zero_address)) == 0)
95 return -EINVAL;
96
97 if (info->oif[0]) {
98 if (info->oif[sizeof(info->oif)-1] != '\0')
99 return -EINVAL;
100
101 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
102 if (priv == NULL)
103 return -ENOMEM;
104
105 priv->tginfo = info;
106 priv->oif = -1;
107 info->priv = priv;
108
109 mutex_lock(&priv_list_mutex);
110 list_add(&priv->list, &priv_list);
111 mutex_unlock(&priv_list_mutex);
112 } else
113 info->priv = NULL;
114
115 static_key_slow_inc(&xt_tee_enabled);
116 return 0;
117 }
118
tee_tg_destroy(const struct xt_tgdtor_param * par)119 static void tee_tg_destroy(const struct xt_tgdtor_param *par)
120 {
121 struct xt_tee_tginfo *info = par->targinfo;
122
123 if (info->priv) {
124 mutex_lock(&priv_list_mutex);
125 list_del(&info->priv->list);
126 mutex_unlock(&priv_list_mutex);
127 kfree(info->priv);
128 }
129 static_key_slow_dec(&xt_tee_enabled);
130 }
131
132 static struct xt_target tee_tg_reg[] __read_mostly = {
133 {
134 .name = "TEE",
135 .revision = 1,
136 .family = NFPROTO_IPV4,
137 .target = tee_tg4,
138 .targetsize = sizeof(struct xt_tee_tginfo),
139 .usersize = offsetof(struct xt_tee_tginfo, priv),
140 .checkentry = tee_tg_check,
141 .destroy = tee_tg_destroy,
142 .me = THIS_MODULE,
143 },
144 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
145 {
146 .name = "TEE",
147 .revision = 1,
148 .family = NFPROTO_IPV6,
149 .target = tee_tg6,
150 .targetsize = sizeof(struct xt_tee_tginfo),
151 .usersize = offsetof(struct xt_tee_tginfo, priv),
152 .checkentry = tee_tg_check,
153 .destroy = tee_tg_destroy,
154 .me = THIS_MODULE,
155 },
156 #endif
157 };
158
159 static struct notifier_block tee_netdev_notifier = {
160 .notifier_call = tee_netdev_event,
161 };
162
tee_tg_init(void)163 static int __init tee_tg_init(void)
164 {
165 int ret;
166
167 ret = xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
168 if (ret)
169 return ret;
170 ret = register_netdevice_notifier(&tee_netdev_notifier);
171 if (ret) {
172 xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
173 return ret;
174 }
175
176 return 0;
177 }
178
tee_tg_exit(void)179 static void __exit tee_tg_exit(void)
180 {
181 unregister_netdevice_notifier(&tee_netdev_notifier);
182 xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
183 }
184
185 module_init(tee_tg_init);
186 module_exit(tee_tg_exit);
187 MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
188 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
189 MODULE_DESCRIPTION("Xtables: Reroute packet copy");
190 MODULE_LICENSE("GPL");
191 MODULE_ALIAS("ipt_TEE");
192 MODULE_ALIAS("ip6t_TEE");
193
