diff --git a/lib/l2cap.h b/lib/l2cap.h
index e59cfdd..bc87f72 100644
--- a/lib/l2cap.h
+++ b/lib/l2cap.h
@@ -83,6 +83,18 @@ struct l2cap_conninfo {
 #define L2CAP_INFO_REQ		0x0a
 #define L2CAP_INFO_RSP		0x0b
 
+/* L2CAP extended feature mask */
+#define L2CAP_FEAT_FLOWCTL	0x00000001
+#define L2CAP_FEAT_RETRANS	0x00000002
+#define L2CAP_FEAT_BIDIR_QOS	0x00000004
+#define L2CAP_FEAT_ERTM		0x00000008
+#define L2CAP_FEAT_STREAMING	0x00000010
+#define L2CAP_FEAT_FCS		0x00000020
+#define L2CAP_FEAT_EXT_FLOW	0x00000040
+#define L2CAP_FEAT_FIXED_CHAN	0x00000080
+#define L2CAP_FEAT_EXT_WINDOW	0x00000100
+#define L2CAP_FEAT_UCD		0x00000200
+
 /* L2CAP structures */
 typedef struct {
 	uint16_t	len;