2 files changed, 83 insertions, 23 deletions

diff --git a/include/linux/netfilter/xt_TEE.h b/include/linux/netfilter/xt_TEE.h
index 55d4a5011523..5c21d5c829af 100644
--- a/include/linux/netfilter/xt_TEE.h
+++ b/include/linux/netfilter/xt_TEE.h
@@ -4,6 +4,9 @@
 struct xt_tee_tginfo {
         union nf_inet_addr gw;
         char oif[16];
+
+        /* used internally by the kernel */
+        struct xt_tee_priv *priv __attribute__((aligned(8)));
 };
 
 #endif /* _XT_TEE_TARGET_H */
diff --git a/net/netfilter/xt_TEE.c b/net/netfilter/xt_TEE.c
index 842e7012eca7..49da6c05f4e0 100644
--- a/net/netfilter/xt_TEE.c
+++ b/net/netfilter/xt_TEE.c
@@ -15,6 +15,7 @@
 #include <linux/percpu.h>
 #include <linux/route.h>
 #include <linux/skbuff.h>
+#include <linux/notifier.h>
 #include <net/checksum.h>
 #include <net/icmp.h>
 #include <net/ip.h>
@@ -32,6 +33,12 @@
 #       define WITH_IPV6 1
 #endif
 
+struct xt_tee_priv {
+        struct notifier_block   notifier;
+        struct xt_tee_tginfo    *tginfo;
+        int                     oif;
+};
+
 static const union nf_inet_addr tee_zero_address;
 static DEFINE_PER_CPU(bool, tee_active);
 
@@ -49,20 +56,6 @@ static struct net *pick_net(struct sk_buff *skb)
         return &init_net;
 }
 
-static bool tee_tg_route_oif(struct flowi *f, struct net *net,
-                             const struct xt_tee_tginfo *info)
-{
-        const struct net_device *dev;
-
-        if (*info->oif != '\0')
-                return true;
-        dev = dev_get_by_name(net, info->oif);
-        if (dev == NULL)
-                return false;
-        f->oif = dev->ifindex;
-        return true;
-}
-
 static bool
 tee_tg_route4(struct sk_buff *skb, const struct xt_tee_tginfo *info)
 {
@@ -72,8 +65,11 @@ tee_tg_route4(struct sk_buff *skb, const struct xt_tee_tginfo *info)
         struct flowi fl;
 
         memset(&fl, 0, sizeof(fl));
-        if (!tee_tg_route_oif(&fl, net, info))
-                return false;
+        if (info->priv) {
+                if (info->priv->oif == -1)
+                        return false;
+                fl.oif = info->priv->oif;
+        }
         fl.nl_u.ip4_u.daddr = info->gw.ip;
         fl.nl_u.ip4_u.tos   = RT_TOS(iph->tos);
         fl.nl_u.ip4_u.scope = RT_SCOPE_UNIVERSE;
@@ -149,8 +145,11 @@ tee_tg_route6(struct sk_buff *skb, const struct xt_tee_tginfo *info)
         struct flowi fl;
 
         memset(&fl, 0, sizeof(fl));
-        if (!tee_tg_route_oif(&fl, net, info))
-                return false;
+        if (info->priv) {
+                if (info->priv->oif == -1)
+                        return false;
+                fl.oif = info->priv->oif;
+        }
         fl.nl_u.ip6_u.daddr = info->gw.in6;
         fl.nl_u.ip6_u.flowlabel = ((iph->flow_lbl[0] & 0xF) << 16) |
                                   (iph->flow_lbl[1] << 8) | iph->flow_lbl[2];
@@ -198,15 +197,71 @@ tee_tg6(struct sk_buff *skb, const struct xt_target_param *par)
 }
 #endif /* WITH_IPV6 */
 
+static int tee_netdev_event(struct notifier_block *this, unsigned long event,
+                            void *ptr)
+{
+        struct net_device *dev = ptr;
+        struct xt_tee_priv *priv;
+
+        priv = container_of(this, struct xt_tee_priv, notifier);
+        switch (event) {
+        case NETDEV_REGISTER:
+                if (!strcmp(dev->name, priv->tginfo->oif))
+                        priv->oif = dev->ifindex;
+                break;
+        case NETDEV_UNREGISTER:
+                if (dev->ifindex == priv->oif)
+                        priv->oif = -1;
+                break;
+        case NETDEV_CHANGENAME:
+                if (!strcmp(dev->name, priv->tginfo->oif))
+                        priv->oif = dev->ifindex;
+                else if (dev->ifindex == priv->oif)
+                        priv->oif = -1;
+                break;
+        }
+
+        return NOTIFY_DONE;
+}
+
 static int tee_tg_check(const struct xt_tgchk_param *par)
 {
-        const struct xt_tee_tginfo *info = par->targinfo;
+        struct xt_tee_tginfo *info = par->targinfo;
+        struct xt_tee_priv *priv;
 
-        if (info->oif[sizeof(info->oif)-1] != '\0')
-                return -EINVAL;
         /* 0.0.0.0 and :: not allowed */
-        return (memcmp(&info->gw, &tee_zero_address,
-               sizeof(tee_zero_address)) == 0) ? -EINVAL : 0;
+        if (memcmp(&info->gw, &tee_zero_address,
+                   sizeof(tee_zero_address)) == 0)
+                return -EINVAL;
+
+        if (info->oif[0]) {
+                if (info->oif[sizeof(info->oif)-1] != '\0')
+                        return -EINVAL;
+
+                priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+                if (priv == NULL)
+                        return -ENOMEM;
+
+                priv->tginfo  = info;
+                priv->oif     = -1;
+                priv->notifier.notifier_call = tee_netdev_event;
+                info->priv    = priv;
+
+                register_netdevice_notifier(&priv->notifier);
+        } else
+                info->priv = NULL;
+
+        return 0;
+}
+
+static void tee_tg_destroy(const struct xt_tgdtor_param *par)
+{
+        struct xt_tee_tginfo *info = par->targinfo;
+
+        if (info->priv) {
+                unregister_netdevice_notifier(&info->priv->notifier);
+                kfree(info->priv);
+        }
 }
 
 static struct xt_target tee_tg_reg[] __read_mostly = {
@@ -217,6 +272,7 @@ static struct xt_target tee_tg_reg[] __read_mostly = {
                 .target     = tee_tg4,
                 .targetsize = sizeof(struct xt_tee_tginfo),
                 .checkentry = tee_tg_check,
+                .destroy    = tee_tg_destroy,
                 .me         = THIS_MODULE,
         },
 #ifdef WITH_IPV6
@@ -227,6 +283,7 @@ static struct xt_target tee_tg_reg[] __read_mostly = {
                 .target     = tee_tg6,
                 .targetsize = sizeof(struct xt_tee_tginfo),
                 .checkentry = tee_tg_check,
+                .destroy    = tee_tg_destroy,
                 .me         = THIS_MODULE,
         },
 #endif