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 int oif = info->priv ? info->priv->oif : 0; 35 36 nf_dup_ipv4(par->net, skb, par->hooknum, &info->gw.in, oif); 37 38 return XT_CONTINUE; 39 } 40 41 #if IS_ENABLED(CONFIG_NF_DUP_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(par->net, skb, par->hooknum, &info->gw.in6, oif); 49 50 return XT_CONTINUE; 51 } 52 #endif 53 54 static int tee_netdev_event(struct notifier_block *this, unsigned long event, 55 void *ptr) 56 { 57 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 58 struct xt_tee_priv *priv; 59 60 priv = container_of(this, struct xt_tee_priv, notifier); 61 switch (event) { 62 case NETDEV_REGISTER: 63 if (!strcmp(dev->name, priv->tginfo->oif)) 64 priv->oif = dev->ifindex; 65 break; 66 case NETDEV_UNREGISTER: 67 if (dev->ifindex == priv->oif) 68 priv->oif = -1; 69 break; 70 case NETDEV_CHANGENAME: 71 if (!strcmp(dev->name, priv->tginfo->oif)) 72 priv->oif = dev->ifindex; 73 else if (dev->ifindex == priv->oif) 74 priv->oif = -1; 75 break; 76 } 77 78 return NOTIFY_DONE; 79 } 80 81 static int tee_tg_check(const struct xt_tgchk_param *par) 82 { 83 struct xt_tee_tginfo *info = par->targinfo; 84 struct xt_tee_priv *priv; 85 86 /* 0.0.0.0 and :: not allowed */ 87 if (memcmp(&info->gw, &tee_zero_address, 88 sizeof(tee_zero_address)) == 0) 89 return -EINVAL; 90 91 if (info->oif[0]) { 92 if (info->oif[sizeof(info->oif)-1] != '\0') 93 return -EINVAL; 94 95 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 96 if (priv == NULL) 97 return -ENOMEM; 98 99 priv->tginfo = info; 100 priv->oif = -1; 101 priv->notifier.notifier_call = tee_netdev_event; 102 info->priv = priv; 103 104 register_netdevice_notifier(&priv->notifier); 105 } else 106 info->priv = NULL; 107 108 static_key_slow_inc(&xt_tee_enabled); 109 return 0; 110 } 111 112 static void tee_tg_destroy(const struct xt_tgdtor_param *par) 113 { 114 struct xt_tee_tginfo *info = par->targinfo; 115 116 if (info->priv) { 117 unregister_netdevice_notifier(&info->priv->notifier); 118 kfree(info->priv); 119 } 120 static_key_slow_dec(&xt_tee_enabled); 121 } 122 123 static struct xt_target tee_tg_reg[] __read_mostly = { 124 { 125 .name = "TEE", 126 .revision = 1, 127 .family = NFPROTO_IPV4, 128 .target = tee_tg4, 129 .targetsize = sizeof(struct xt_tee_tginfo), 130 .checkentry = tee_tg_check, 131 .destroy = tee_tg_destroy, 132 .me = THIS_MODULE, 133 }, 134 #if IS_ENABLED(CONFIG_NF_DUP_IPV6) 135 { 136 .name = "TEE", 137 .revision = 1, 138 .family = NFPROTO_IPV6, 139 .target = tee_tg6, 140 .targetsize = sizeof(struct xt_tee_tginfo), 141 .checkentry = tee_tg_check, 142 .destroy = tee_tg_destroy, 143 .me = THIS_MODULE, 144 }, 145 #endif 146 }; 147 148 static int __init tee_tg_init(void) 149 { 150 return xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); 151 } 152 153 static void __exit tee_tg_exit(void) 154 { 155 xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); 156 } 157 158 module_init(tee_tg_init); 159 module_exit(tee_tg_exit); 160 MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>"); 161 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); 162 MODULE_DESCRIPTION("Xtables: Reroute packet copy"); 163 MODULE_LICENSE("GPL"); 164 MODULE_ALIAS("ipt_TEE"); 165 MODULE_ALIAS("ip6t_TEE"); 166