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 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_IPV6) 42 static unsigned int 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 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 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 } 118 119 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_IPV6) 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 }; 162 163 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 } 178 179 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