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, 7 insertions, 0 deletions

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index f8c549281c30..33e99462023a 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -217,6 +217,13 @@ bool dsa_uses_dsa_tags(void *dsa_ptr)
         return !!(ds->tag_protocol == htons(ETH_P_DSA));
 }
 
+bool dsa_uses_trailer_tags(void *dsa_ptr)
+{
+        struct dsa_switch *ds = dsa_ptr;
+
+        return !!(ds->tag_protocol == htons(ETH_P_TRAILER));
+}
+
 
 /* link polling *************************************************************/
 static void dsa_link_poll_work(struct work_struct *ugly)