net: Add STP demux layer

Add small STP demux layer for demuxing STP PDUs based on MAC address.
This is needed to run both GARP and STP in parallel (or even load the
modules) since both use LLC_SAP_BSPAN.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/stp.h b/include/net/stp.h
new file mode 100644
index 0000000..ad447f1
--- /dev/null
+++ b/include/net/stp.h
@@ -0,0 +1,14 @@
+#ifndef _NET_STP_H
+#define _NET_STP_H
+
+struct stp_proto {
+	unsigned char	group_address[ETH_ALEN];
+	void		(*rcv)(const struct stp_proto *, struct sk_buff *,
+			       struct net_device *);
+	void		*data;
+};
+
+extern int stp_proto_register(const struct stp_proto *proto);
+extern void stp_proto_unregister(const struct stp_proto *proto);
+
+#endif /* _NET_STP_H */