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netfilter: Rework xt_TEE netdevice notifier

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Register netdevice notifier for every iptable entry
is not good, since this breaks modularity, and
the hidden synchronization is based on rtnl_lock().

This patch reworks the synchronization via new lock,
while the rest of logic remains as it was before.
This is required for the next patch.

Tested via:

while :; do
	unshare -n iptables -t mangle -A OUTPUT -j TEE --gateway 1.1.1.2 --oif lo;
done

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kirill Tkhai 2018-03-29 17:03:35 +03:00 committed by David S. Miller
parent e9a441b6e7
commit 9e2f6c5d78
1 changed files with 46 additions and 27 deletions
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73
net/netfilter/xt_TEE.c
View File

@ -20,7 +20,7 @@
#include <linux/netfilter/xt_TEE.h> #include <linux/netfilter/xt_TEE.h>
struct xt_tee_priv { struct xt_tee_priv {
struct notifier_block notifier; struct list_head list;
struct xt_tee_tginfo *tginfo; struct xt_tee_tginfo *tginfo;
int oif; int oif;
}; };
@ -51,29 +51,35 @@ tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
} }
#endif #endif
static DEFINE_MUTEX(priv_list_mutex);
static LIST_HEAD(priv_list);
static int tee_netdev_event(struct notifier_block *this, unsigned long event, static int tee_netdev_event(struct notifier_block *this, unsigned long event,
void *ptr) void *ptr)
{ {
struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct xt_tee_priv *priv; struct xt_tee_priv *priv;
priv = container_of(this, struct xt_tee_priv, notifier); mutex_lock(&priv_list_mutex);
switch (event) { list_for_each_entry(priv, &priv_list, list) {
case NETDEV_REGISTER: switch (event) {
if (!strcmp(dev->name, priv->tginfo->oif)) case NETDEV_REGISTER:
priv->oif = dev->ifindex; if (!strcmp(dev->name, priv->tginfo->oif))
break; priv->oif = dev->ifindex;
case NETDEV_UNREGISTER: break;
if (dev->ifindex == priv->oif) case NETDEV_UNREGISTER:
priv->oif = -1; if (dev->ifindex == priv->oif)
break; priv->oif = -1;
case NETDEV_CHANGENAME: break;
if (!strcmp(dev->name, priv->tginfo->oif)) case NETDEV_CHANGENAME:
priv->oif = dev->ifindex; if (!strcmp(dev->name, priv->tginfo->oif))
else if (dev->ifindex == priv->oif) priv->oif = dev->ifindex;
priv->oif = -1; else if (dev->ifindex == priv->oif)
break; priv->oif = -1;
break;
}
} }
mutex_unlock(&priv_list_mutex);
return NOTIFY_DONE; return NOTIFY_DONE;
} }
@ -89,8 +95,6 @@ static int tee_tg_check(const struct xt_tgchk_param *par)
return -EINVAL; return -EINVAL;
if (info->oif[0]) { if (info->oif[0]) {
int ret;
if (info->oif[sizeof(info->oif)-1] != '\0') if (info->oif[sizeof(info->oif)-1] != '\0')
return -EINVAL; return -EINVAL;
@ -100,14 +104,11 @@ static int tee_tg_check(const struct xt_tgchk_param *par)
priv->tginfo = info; priv->tginfo = info;
priv->oif = -1; priv->oif = -1;
priv->notifier.notifier_call = tee_netdev_event;
info->priv = priv; info->priv = priv;
ret = register_netdevice_notifier(&priv->notifier); mutex_lock(&priv_list_mutex);
if (ret) { list_add(&priv->list, &priv_list);
kfree(priv); mutex_unlock(&priv_list_mutex);
return ret;
}
} else } else
info->priv = NULL; info->priv = NULL;
@ -120,7 +121,9 @@ static void tee_tg_destroy(const struct xt_tgdtor_param *par)
struct xt_tee_tginfo *info = par->targinfo; struct xt_tee_tginfo *info = par->targinfo;
if (info->priv) { if (info->priv) {
unregister_netdevice_notifier(&info->priv->notifier); mutex_lock(&priv_list_mutex);
list_del(&info->priv->list);
mutex_unlock(&priv_list_mutex);
kfree(info->priv); kfree(info->priv);
} }
static_key_slow_dec(&xt_tee_enabled); static_key_slow_dec(&xt_tee_enabled);
@ -153,13 +156,29 @@ static struct xt_target tee_tg_reg[] __read_mostly = {
#endif #endif
}; };
static struct notifier_block tee_netdev_notifier = {
.notifier_call = tee_netdev_event,
};
static int __init tee_tg_init(void) static int __init tee_tg_init(void)
{ {
return xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); int ret;
ret = xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
if (ret)
return ret;
ret = register_netdevice_notifier(&tee_netdev_notifier);
if (ret) {
xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
return ret;
}
return 0;
} }
static void __exit tee_tg_exit(void) static void __exit tee_tg_exit(void)
{ {
unregister_netdevice_notifier(&tee_netdev_notifier);
xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg)); xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
} }