From d566c3314bf64dce10648e2b95c11b23b32b3135 Mon Sep 17 00:00:00 2001
From: Louis Caron <louis.caron@intel.com>
Date: Fri, 11 Dec 2015 09:48:57 +0100
Subject: [PATCH] Bluetooth: add CUD descriptor support

In order to support more standard descriptors, the UD macro and helper
function are added.

Change-Id: Ic9a82658668107b40abc5c98002fe5091dc10f08
Signed-off-by: Louis Caron <louis.caron@intel.com>
---
 include/bluetooth/gatt.h | 41 ++++++++++++++++++++++++++++++++++------
 net/bluetooth/gatt.c     |  9 +++++++++
 2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/include/bluetooth/gatt.h b/include/bluetooth/gatt.h
index 76ef0e16d3c..58c6dbe2fb6 100644
--- a/include/bluetooth/gatt.h
+++ b/include/bluetooth/gatt.h
@@ -191,12 +191,6 @@ struct bt_gatt_cep {
 	uint16_t		properties;
 };
 
-/** @brief Characteristic User Description Attribute Value. */
-struct bt_gatt_cud {
-	/** Characteristic User Description string. */
-	char			*string;
-};
-
 /* Client Characteristic Configuration Values */
 
 /** @def BT_GATT_CCC_NOTIFY
@@ -523,6 +517,41 @@ int bt_gatt_attr_read_cep(struct bt_conn *conn,
 	.user_data = _value,						\
 }
 
+/** @brief Read Characteristic User Description Descriptor Attribute helper
+ *
+ *  Read CUD attribute value storing the result into buffer after
+ *  encoding it.
+ *  NOTE: Only use this with attributes which user_data is a NULL-terminated C string.
+ *
+ *  @param conn Connection object
+ *  @param attr Attribute to read
+ *  @param buf Buffer to store the value read
+ *  @param len Buffer length
+ *  @param offset Start offset
+ *
+ *  @return number of bytes read in case of success or negative values in
+ *  case of error.
+ */
+int bt_gatt_attr_read_cud(struct bt_conn *conn,
+			  const struct bt_gatt_attr *attr, void *buf,
+			  uint16_t len, uint16_t offset);
+
+/** @def BT_GATT_CUD
+ *  @brief Characteristic User Format Descriptor Declaration Macro.
+ *
+ *  Helper macro to declare a CUD attribute.
+ *
+ *  @param _value User description NULL-terminated C string.
+ *  @param _perm Descriptor attribute access permissions.
+ */
+#define BT_GATT_CUD(_value, _perm)					\
+{									\
+	.uuid = BT_UUID_GATT_CUD,					\
+	.perm = _perm,							\
+	.read = bt_gatt_attr_read_cud,					\
+	.user_data = _value,						\
+}
+
 /** @def BT_GATT_DESCRIPTOR
  *  @brief Descriptor Declaration Macro.
  *
diff --git a/net/bluetooth/gatt.c b/net/bluetooth/gatt.c
index f04e5dbcde0..6bf0b0c1ab0 100644
--- a/net/bluetooth/gatt.c
+++ b/net/bluetooth/gatt.c
@@ -349,6 +349,15 @@ int bt_gatt_attr_read_cep(struct bt_conn *conn,
 				 sizeof(props));
 }
 
+int bt_gatt_attr_read_cud(struct bt_conn *conn,
+			  const struct bt_gatt_attr *attr, void *buf,
+			  uint16_t len, uint16_t offset)
+{
+	char *value = attr->user_data;
+
+	return bt_gatt_attr_read(conn, attr, buf, len, offset, value, strlen(value));
+}
+
 struct notify_data {
 	const void *data;
 	size_t len;