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>

3 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h
index 32b9dcda68c7..a0099e98b5c4 100644
--- a/include/linux/if_ether.h
+++ b/include/linux/if_ether.h
@@ -102,6 +102,7 @@
 #define ETH_P_HDLC      0x0019          /* HDLC frames                  */
 #define ETH_P_ARCNET    0x001A          /* 1A for ArcNet :-)            */
 #define ETH_P_DSA       0x001B          /* Distributed Switch Arch.     */
+#define ETH_P_TRAILER   0x001C          /* Trailer switch tagging       */
 #define ETH_P_PHONET    0x00F5          /* Nokia Phonet frames          */
 
 /*
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
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 72e509b6a12e..52e97bfca5a1 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -31,6 +31,7 @@ struct dsa_platform_data {
 };
 
 extern bool dsa_uses_dsa_tags(void *dsa_ptr);
+extern bool dsa_uses_trailer_tags(void *dsa_ptr);
 
 
 #endif