dsa: add support for Trailer tagging format

This adds support for the Trailer switch tagging format.  This is
another tagging that doesn't explicitly mark tagged packets with a
distinct ethertype, so that we need to add a similar hack in the
receive path as for the Original DSA tagging format.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Tested-by: Byron Bradley <byron.bbradley@gmail.com>
Tested-by: Tim Ellis <tim.ellis@mac.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 97f0c64c152a..d3ea3de70a8a 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -812,6 +812,16 @@ static inline bool netdev_uses_dsa_tags(struct net_device *dev)
         return 0;
 }
 
+static inline bool netdev_uses_trailer_tags(struct net_device *dev)
+{
+#ifdef CONFIG_NET_DSA_TAG_TRAILER
+        if (dev->dsa_ptr != NULL)
+                return dsa_uses_trailer_tags(dev->dsa_ptr);
+#endif
+
+        return 0;
+}
+
 /**
  *      netdev_priv - access network device private data
  *      @dev: network device