// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* "TEE" target extension for Xtables
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* Copyright © Sebastian Claßen, 2007
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* Jan Engelhardt, 2007-2010
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*
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* based on ipt_ROUTE.c from Cédric de Launois
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* <delaunois@info.ucl.be>
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/route.h>
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#include <linux/netfilter/x_tables.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include <net/route.h>
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#include <net/netfilter/ipv4/nf_dup_ipv4.h>
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#include <net/netfilter/ipv6/nf_dup_ipv6.h>
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#include <linux/netfilter/xt_TEE.h>
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struct xt_tee_priv {
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struct list_head list;
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struct xt_tee_tginfo *tginfo;
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int oif;
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};
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static unsigned int tee_net_id __read_mostly;
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static const union nf_inet_addr tee_zero_address;
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struct tee_net {
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struct list_head priv_list;
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/* lock protects the priv_list */
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struct mutex lock;
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};
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static unsigned int
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tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_tee_tginfo *info = par->targinfo;
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int oif = info->priv ? info->priv->oif : 0;
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nf_dup_ipv4(xt_net(par), skb, xt_hooknum(par), &info->gw.in, oif);
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return XT_CONTINUE;
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}
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#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
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static unsigned int
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tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_tee_tginfo *info = par->targinfo;
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int oif = info->priv ? info->priv->oif : 0;
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nf_dup_ipv6(xt_net(par), skb, xt_hooknum(par), &info->gw.in6, oif);
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return XT_CONTINUE;
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}
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#endif
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static int tee_netdev_event(struct notifier_block *this, unsigned long event,
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void *ptr)
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{
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struct net_device *dev = netdev_notifier_info_to_dev(ptr);
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struct net *net = dev_net(dev);
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struct tee_net *tn = net_generic(net, tee_net_id);
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struct xt_tee_priv *priv;
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mutex_lock(&tn->lock);
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list_for_each_entry(priv, &tn->priv_list, list) {
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switch (event) {
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case NETDEV_REGISTER:
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if (!strcmp(dev->name, priv->tginfo->oif))
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priv->oif = dev->ifindex;
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break;
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case NETDEV_UNREGISTER:
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if (dev->ifindex == priv->oif)
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priv->oif = -1;
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break;
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case NETDEV_CHANGENAME:
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if (!strcmp(dev->name, priv->tginfo->oif))
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priv->oif = dev->ifindex;
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else if (dev->ifindex == priv->oif)
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priv->oif = -1;
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break;
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}
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}
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mutex_unlock(&tn->lock);
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return NOTIFY_DONE;
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}
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static int tee_tg_check(const struct xt_tgchk_param *par)
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{
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struct tee_net *tn = net_generic(par->net, tee_net_id);
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struct xt_tee_tginfo *info = par->targinfo;
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struct xt_tee_priv *priv;
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/* 0.0.0.0 and :: not allowed */
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if (memcmp(&info->gw, &tee_zero_address,
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sizeof(tee_zero_address)) == 0)
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return -EINVAL;
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if (info->oif[0]) {
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struct net_device *dev;
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if (info->oif[sizeof(info->oif)-1] != '\0')
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return -EINVAL;
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (priv == NULL)
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return -ENOMEM;
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priv->tginfo = info;
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priv->oif = -1;
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info->priv = priv;
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dev = dev_get_by_name(par->net, info->oif);
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if (dev) {
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priv->oif = dev->ifindex;
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dev_put(dev);
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}
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mutex_lock(&tn->lock);
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list_add(&priv->list, &tn->priv_list);
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mutex_unlock(&tn->lock);
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} else
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info->priv = NULL;
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static_key_slow_inc(&xt_tee_enabled);
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return 0;
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}
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static void tee_tg_destroy(const struct xt_tgdtor_param *par)
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{
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struct tee_net *tn = net_generic(par->net, tee_net_id);
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struct xt_tee_tginfo *info = par->targinfo;
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if (info->priv) {
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mutex_lock(&tn->lock);
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list_del(&info->priv->list);
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mutex_unlock(&tn->lock);
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kfree(info->priv);
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}
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static_key_slow_dec(&xt_tee_enabled);
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}
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static struct xt_target tee_tg_reg[] __read_mostly = {
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{
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.name = "TEE",
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.revision = 1,
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.family = NFPROTO_IPV4,
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.target = tee_tg4,
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.targetsize = sizeof(struct xt_tee_tginfo),
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.usersize = offsetof(struct xt_tee_tginfo, priv),
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.checkentry = tee_tg_check,
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.destroy = tee_tg_destroy,
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.me = THIS_MODULE,
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},
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#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
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{
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.name = "TEE",
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.revision = 1,
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.family = NFPROTO_IPV6,
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.target = tee_tg6,
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.targetsize = sizeof(struct xt_tee_tginfo),
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.usersize = offsetof(struct xt_tee_tginfo, priv),
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.checkentry = tee_tg_check,
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.destroy = tee_tg_destroy,
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.me = THIS_MODULE,
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},
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#endif
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};
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static int __net_init tee_net_init(struct net *net)
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{
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struct tee_net *tn = net_generic(net, tee_net_id);
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INIT_LIST_HEAD(&tn->priv_list);
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mutex_init(&tn->lock);
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return 0;
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}
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static struct pernet_operations tee_net_ops = {
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.init = tee_net_init,
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.id = &tee_net_id,
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.size = sizeof(struct tee_net),
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};
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static struct notifier_block tee_netdev_notifier = {
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.notifier_call = tee_netdev_event,
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};
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static int __init tee_tg_init(void)
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{
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int ret;
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ret = register_pernet_subsys(&tee_net_ops);
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if (ret < 0)
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return ret;
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ret = xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
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if (ret < 0)
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goto cleanup_subsys;
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ret = register_netdevice_notifier(&tee_netdev_notifier);
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if (ret < 0)
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goto unregister_targets;
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return 0;
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unregister_targets:
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xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
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cleanup_subsys:
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unregister_pernet_subsys(&tee_net_ops);
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return ret;
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}
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static void __exit tee_tg_exit(void)
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{
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unregister_netdevice_notifier(&tee_netdev_notifier);
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xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
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unregister_pernet_subsys(&tee_net_ops);
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}
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module_init(tee_tg_init);
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module_exit(tee_tg_exit);
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MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
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MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
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MODULE_DESCRIPTION("Xtables: Reroute packet copy");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("ipt_TEE");
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MODULE_ALIAS("ip6t_TEE");
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