Add attribute id for additional protocol list
diff --git a/include/sdp.h b/include/sdp.h
index 13205b9..e62ab87 100644
--- a/include/sdp.h
+++ b/include/sdp.h
@@ -150,6 +150,7 @@
 #define SDP_ATTR_DOC_URL		0x000A
 #define SDP_ATTR_CLNT_EXEC_URL		0x000B
 #define SDP_ATTR_ICON_URL		0x000C
+#define SDP_ATTR_ADD_PROTO_DESC_LIST	0x000D
 
 #define SDP_ATTR_IP_SUBNET			0x0200
 #define SDP_ATTR_SERVICE_VERSION		0x0300