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 notifier_block notifier; 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 35 nf_dup_ipv4(skb, par->hooknum, &info->gw.in, info->priv->oif); 36 37 return XT_CONTINUE; 38 } 39 40 #if IS_ENABLED(CONFIG_NF_DUP_IPV6) 41 static unsigned int 42 tee_tg6(struct sk_buff *skb, const struct xt_action_param *par) 43 { 44 const struct xt_tee_tginfo *info = par->targinfo; 45 46 nf_dup_ipv6(skb, par->hooknum, &info->gw.in6, info->priv->oif); 47 48 return XT_CONTINUE; 49 } 50 #endif 51 52 static int tee_netdev_event(struct notifier_block *this, unsigned long event, 53 void *ptr) 54 { 55 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 56 struct xt_tee_priv *priv; 57 58 priv = container_of(this, struct xt_tee_priv, notifier); 59 switch (event) { 60 case NETDEV_REGISTER: 61 if (!strcmp(dev->name, priv->tginfo->oif)) 62 priv->oif = dev->ifindex; 63 break; 64 case NETDEV_UNREGISTER: 65 if (dev->ifindex == priv->oif) 66 priv->oif = -1; 67 break; 68 case NETDEV_CHANGENAME: 69 if (!strcmp(dev->name, priv->tginfo->oif)) 70 priv->oif = dev->ifindex; 71 else if (dev->ifindex == priv->oif) 72 priv->oif = -1; 73 break; 74 } 75 76 return NOTIFY_DONE; 77 } 78 79 static int tee_tg_check(const struct xt_tgchk_param *par) 80 { 81 struct xt_tee_tginfo *info = par->targinfo; 82 struct xt_tee_priv *priv; 83 84 /* 0.0.0.0 and :: not allowed */ 85 if (memcmp(&info->gw, &tee_zero_address, 86 sizeof(tee_zero_address)) == 0) 87 return -EINVAL; 88 89 if (info->oif[0]) { 90 if (info->oif[sizeof(info->oif)-1] != '\0') 91 return -EINVAL; 92 93 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 94 if (priv == NULL) 95 return -ENOMEM; 96 97 priv->tginfo = info; 98 priv->oif = -1; 99 priv->notifier.notifier_call = tee_netdev_event; 100 info->priv = priv; 101 102 register_netdevice_notifier(&priv->notifier); 103 } else 104 info->priv = NULL; 105 106 static_key_slow_inc(&xt_tee_enabled); 107 return 0; 108 } 109 110 static void tee_tg_destroy(const struct xt_tgdtor_param *par) 111 { 112 struct xt_tee_tginfo *info = par->targinfo; 113 114 if (info->priv) { 115 unregister_netdevice_notifier(&info->priv->notifier); 116 kfree(info->priv); 117 } 118 static_key_slow_dec(&xt_tee_enabled); 119 } 120 121 static struct xt_target tee_tg_reg[] __read_mostly = { 122 { 123 .name = "TEE", 124 .revision = 1, 125 .family = NFPROTO_IPV4, 126 .target = tee_tg4, 127 .targetsize = sizeof(struct xt_tee_tginfo), 128 .checkentry = tee_tg_check, 129 .destroy = tee_tg_destroy, 130 .me = THIS_MODULE, 131 }, 132 #if IS_ENABLED(CONFIG_NF_DUP_IPV6) 133 { 134 .name = "TEE", 135 .revision = 1, 136 .family = NFPROTO_IPV6, 137 .target = tee_tg6, 138 .targetsize = sizeof(struct xt_tee_tginfo), 139 .checkentry = tee_tg_check, 140 .destroy = tee_tg_destroy, 141 .me = THIS_MODULE, 142 }, 143 #endif 144 }; 145 146 static int __init tee_tg_init(void) 147 { 148 return xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); 149 } 150 151 static void __exit tee_tg_exit(void) 152 { 153 xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); 154 } 155 156 module_init(tee_tg_init); 157 module_exit(tee_tg_exit); 158 MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>"); 159 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); 160 MODULE_DESCRIPTION("Xtables: Reroute packet copy"); 161 MODULE_LICENSE("GPL"); 162 MODULE_ALIAS("ipt_TEE"); 163 MODULE_ALIAS("ip6t_TEE"); 164