3 files changed, 78 insertions, 2 deletions

diff --git a/Documentation/networking/mpls-sysctl.txt b/Documentation/networking/mpls-sysctl.txt
index 639ddf0ece9b..9ed15f86c17c 100644
--- a/Documentation/networking/mpls-sysctl.txt
+++ b/Documentation/networking/mpls-sysctl.txt
@@ -18,3 +18,12 @@ platform_labels - INTEGER
 
         Possible values: 0 - 1048575
         Default: 0
+
+conf/<interface>/input - BOOL
+        Control whether packets can be input on this interface.
+
+        If disabled, packets will be discarded without further
+        processing.
+
+        0 - disabled (default)
+        not 0 - enabled
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index ad45017eed99..9fdd94cba83e 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -150,7 +150,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
         /* Careful this entire function runs inside of an rcu critical section */
 
         mdev = mpls_dev_get(dev);
-        if (!mdev)
+        if (!mdev || !mdev->input_enabled)
                 goto drop;
 
         if (skb->pkt_type != PACKET_HOST)
@@ -438,6 +438,60 @@ errout:
         return err;
 }
 
+#define MPLS_PERDEV_SYSCTL_OFFSET(field)        \
+        (&((struct mpls_dev *)0)->field)
+
+static const struct ctl_table mpls_dev_table[] = {
+        {
+                .procname       = "input",
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec,
+                .data           = MPLS_PERDEV_SYSCTL_OFFSET(input_enabled),
+        },
+        { }
+};
+
+static int mpls_dev_sysctl_register(struct net_device *dev,
+                                    struct mpls_dev *mdev)
+{
+        char path[sizeof("net/mpls/conf/") + IFNAMSIZ];
+        struct ctl_table *table;
+        int i;
+
+        table = kmemdup(&mpls_dev_table, sizeof(mpls_dev_table), GFP_KERNEL);
+        if (!table)
+                goto out;
+
+        /* Table data contains only offsets relative to the base of
+         * the mdev at this point, so make them absolute.
+         */
+        for (i = 0; i < ARRAY_SIZE(mpls_dev_table); i++)
+                table[i].data = (char *)mdev + (uintptr_t)table[i].data;
+
+        snprintf(path, sizeof(path), "net/mpls/conf/%s", dev->name);
+
+        mdev->sysctl = register_net_sysctl(dev_net(dev), path, table);
+        if (!mdev->sysctl)
+                goto free;
+
+        return 0;
+
+free:
+        kfree(table);
+out:
+        return -ENOBUFS;
+}
+
+static void mpls_dev_sysctl_unregister(struct mpls_dev *mdev)
+{
+        struct ctl_table *table;
+
+        table = mdev->sysctl->ctl_table_arg;
+        unregister_net_sysctl_table(mdev->sysctl);
+        kfree(table);
+}
+
 static struct mpls_dev *mpls_add_dev(struct net_device *dev)
 {
         struct mpls_dev *mdev;
@@ -449,9 +503,17 @@ static struct mpls_dev *mpls_add_dev(struct net_device *dev)
         if (!mdev)
                 return ERR_PTR(err);
 
+        err = mpls_dev_sysctl_register(dev, mdev);
+        if (err)
+                goto free;
+
         rcu_assign_pointer(dev->mpls_ptr, mdev);
 
         return mdev;
+
+free:
+        kfree(mdev);
+        return ERR_PTR(err);
 }
 
 static void mpls_ifdown(struct net_device *dev)
@@ -475,6 +537,8 @@ static void mpls_ifdown(struct net_device *dev)
         if (!mdev)
                 return;
 
+        mpls_dev_sysctl_unregister(mdev);
+
         RCU_INIT_POINTER(dev->mpls_ptr, NULL);
 
         kfree(mdev);
@@ -958,7 +1022,7 @@ static int mpls_platform_labels(struct ctl_table *table, int write,
         return ret;
 }
 
-static struct ctl_table mpls_table[] = {
+static const struct ctl_table mpls_table[] = {
         {
                 .procname       = "platform_labels",
                 .data           = NULL,
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index 8090cb3099b4..693877d69606 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -23,6 +23,9 @@ struct mpls_entry_decoded {
 };
 
 struct mpls_dev {
+        int                     input_enabled;
+
+        struct ctl_table_header *sysctl;
 };
 
 struct sk_buff;