mpls: Per-device MPLS state

Add per-device MPLS state to supported interfaces. Use the presence of
this state in mpls_route_add to determine that this is a supported
interface.

Use the presence of mpls_dev to drop packets that arrived on an
unsupported interface - previously they were allowed through.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Robert Shearman <rshearma@brocade.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 55 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index bcbde799ec69..dae106a3a998 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -60,6 +60,7 @@ struct phy_device;
 struct wireless_dev;
 /* 802.15.4 specific */
 struct wpan_dev;
+struct mpls_dev;
 
 void netdev_set_default_ethtool_ops(struct net_device *dev,
                                     const struct ethtool_ops *ops);
@@ -1627,6 +1628,9 @@ struct net_device {
         void                    *ax25_ptr;
         struct wireless_dev     *ieee80211_ptr;
         struct wpan_dev         *ieee802154_ptr;
+#if IS_ENABLED(CONFIG_MPLS_ROUTING)
+        struct mpls_dev __rcu   *mpls_ptr;
+#endif
 
 /*
  * Cache lines mostly used on receive path (including eth_type_trans())
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index db8a2ea6d4de..ad45017eed99 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -53,6 +53,11 @@ static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned index)
         return rt;
 }
 
+static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)
+{
+        return rcu_dereference_rtnl(dev->mpls_ptr);
+}
+
 static bool mpls_output_possible(const struct net_device *dev)
 {
         return dev && (dev->flags & IFF_UP) && netif_carrier_ok(dev);
@@ -136,6 +141,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
         struct mpls_route *rt;
         struct mpls_entry_decoded dec;
         struct net_device *out_dev;
+        struct mpls_dev *mdev;
         unsigned int hh_len;
         unsigned int new_header_size;
         unsigned int mtu;
@@ -143,6 +149,10 @@ 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)
+                goto drop;
+
         if (skb->pkt_type != PACKET_HOST)
                 goto drop;
 
@@ -352,9 +362,9 @@ static int mpls_route_add(struct mpls_route_config *cfg)
         if (!dev)
                 goto errout;
 
-        /* For now just support ethernet devices */
+        /* Ensure this is a supported device */
         err = -EINVAL;
-        if ((dev->type != ARPHRD_ETHER) && (dev->type != ARPHRD_LOOPBACK))
+        if (!mpls_dev_get(dev))
                 goto errout;
 
         err = -EINVAL;
@@ -428,10 +438,27 @@ errout:
         return err;
 }
 
+static struct mpls_dev *mpls_add_dev(struct net_device *dev)
+{
+        struct mpls_dev *mdev;
+        int err = -ENOMEM;
+
+        ASSERT_RTNL();
+
+        mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+        if (!mdev)
+                return ERR_PTR(err);
+
+        rcu_assign_pointer(dev->mpls_ptr, mdev);
+
+        return mdev;
+}
+
 static void mpls_ifdown(struct net_device *dev)
 {
         struct mpls_route __rcu **platform_label;
         struct net *net = dev_net(dev);
+        struct mpls_dev *mdev;
         unsigned index;
 
         platform_label = rtnl_dereference(net->mpls.platform_label);
@@ -443,14 +470,33 @@ static void mpls_ifdown(struct net_device *dev)
                         continue;
                 rt->rt_dev = NULL;
         }
+
+        mdev = mpls_dev_get(dev);
+        if (!mdev)
+                return;
+
+        RCU_INIT_POINTER(dev->mpls_ptr, NULL);
+
+        kfree(mdev);
 }
 
 static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
                            void *ptr)
 {
         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+        struct mpls_dev *mdev;
 
         switch(event) {
+        case NETDEV_REGISTER:
+                /* For now just support ethernet devices */
+                if ((dev->type == ARPHRD_ETHER) ||
+                    (dev->type == ARPHRD_LOOPBACK)) {
+                        mdev = mpls_add_dev(dev);
+                        if (IS_ERR(mdev))
+                                return notifier_from_errno(PTR_ERR(mdev));
+                }
+                break;
+
         case NETDEV_UNREGISTER:
                 mpls_ifdown(dev);
                 break;
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index fb6de92052c4..8090cb3099b4 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -22,6 +22,9 @@ struct mpls_entry_decoded {
         u8 bos;
 };
 
+struct mpls_dev {
+};
+
 struct sk_buff;
 
 static inline struct mpls_shim_hdr *mpls_hdr(const struct sk_buff *skb)