This patch adds the Client Characteristic discovery of the Service
Changed Changed characteristic.
---
profiles/gatt/gas.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 102 insertions(+), 5 deletions(-)
diff --git a/profiles/gatt/gas.c b/profiles/gatt/gas.c
index 01017fe..d36a457 100644
--- a/profiles/gatt/gas.c
+++ b/profiles/gatt/gas.c
@@ -43,6 +43,8 @@ struct gas {
struct att_range gatt; /* GATT Primary service range */
GAttrib *attrib;
guint attioid;
+ guint changed_ind;
+ uint16_t changed_handle;
};
static GSList *devices = NULL;
@@ -98,6 +100,26 @@ done:
att_data_list_free(list);
}
+static void indication_cb(const uint8_t *pdu, uint16_t len, gpointer user_data)
+{
+ struct gas *gas = user_data;
+ uint16_t handle, start, end;
+
+ if (len < 7) { /* 1-byte opcode + 2-byte handle + 4 range */
+ error("Malformed ATT notification");
+ return;
+ }
+
+ handle = att_get_u16(&pdu[1]);
+ start = att_get_u16(&pdu[3]);
+ end = att_get_u16(&pdu[5]);
+
+ if (handle != gas->changed_handle)
+ return;
+
+ DBG("Service Changed start: 0x%04X end: 0x%04X", start, end);
+}
+
static void gatt_service_changed_cb(guint8 status, const guint8 *pdu,
guint16 plen, gpointer user_data)
{
@@ -120,14 +142,76 @@ static void gatt_service_changed_cb(guint8 status, const guint8 *pdu,
DBG("GATT Service Changed start: 0x%04X end: 0x%04X", start, end);
}
+static void gatt_descriptors_cb(guint8 status, const guint8 *pdu, guint16 len,
+ gpointer user_data)
+{
+ struct att_data_list *list;
+ int i;
+ uint8_t format;
+
+ if (status) {
+ error("Discover all GATT characteristic descriptors: %s",
+ att_ecode2str(status));
+ return;
+ }
+
+ list = dec_find_info_resp(pdu, len, &format);
+ if (list == NULL)
+ return;
+
+ if (format != 0x01)
+ goto done;
+
+ for (i = 0; i < list->num; i++) {
+ uint16_t uuid16, ccc;
+ uint8_t *value;
+
+ value = list->data[i];
+ ccc = att_get_u16(value);
+ uuid16 = att_get_u16(&value[2]);
+ DBG("CCC: 0x%04x UUID: 0x%04x", ccc, uuid16);
+ }
+
+done:
+ att_data_list_free(list);
+}
+
+static void gatt_characteristic_cb(GSList *characteristics, guint8 status,
+ gpointer user_data)
+{
+ struct gas *gas = user_data;
+ struct gatt_char *chr;
+ uint16_t start, end;
+
+ if (status) {
+ error("Discover Service Changed handle: %s", att_ecode2str(status));
+ return;
+ }
+
+ chr = characteristics->data;
+
+ start = chr->value_handle + 1;
+ end = gas->gatt.end;
+
+ if (start <= end) {
+ error("Inconsistent database: Service Changed CCC missing");
+ return;
+ }
+
+ gas->changed_handle = chr->value_handle;
+ gatt_find_info(gas->attrib, start, end, gatt_descriptors_cb, gas);
+}
+
static void attio_connected_cb(GAttrib *attrib, gpointer user_data)
{
struct gas *gas = user_data;
- bt_uuid_t changed_uuid;
uint16_t app;
gas->attrib = g_attrib_ref(attrib);
+ gas->changed_ind = g_attrib_register(gas->attrib, ATT_OP_HANDLE_IND,
+ indication_cb, gas, NULL);
+
if (device_get_appearance(gas->device, &app) < 0) {
bt_uuid_t uuid;
@@ -143,18 +227,31 @@ static void attio_connected_cb(GAttrib *attrib, gpointer user_data)
/*
* Always read the characteristic value in the first connection
* since attribute handles caching is not supported at the moment.
+ * When re-connecting <<Service Changed>> handle and characteristic
+ * value doesn't need to read again: known information from the
+ * previous interaction.
*/
- bt_uuid16_create(&changed_uuid, GATT_CHARAC_SERVICE_CHANGED);
+ if (gas->changed_handle == 0) {
+ bt_uuid_t uuid;
+
+ bt_uuid16_create(&uuid, GATT_CHARAC_SERVICE_CHANGED);
- gatt_read_char_by_uuid(gas->attrib, gas->gatt.start,
- gas->gatt.end, &changed_uuid,
- gatt_service_changed_cb, gas);
+ gatt_read_char_by_uuid(gas->attrib, gas->gatt.start,
+ gas->gatt.end, &uuid,
+ gatt_service_changed_cb, gas);
+
+ gatt_discover_char(gas->attrib, gas->gatt.start, gas->gatt.end,
+ &uuid, gatt_characteristic_cb, gas);
+ }
}
static void attio_disconnected_cb(gpointer user_data)
{
struct gas *gas = user_data;
+ g_attrib_unregister(gas->attrib, gas->changed_ind);
+ gas->changed_ind = 0;
+
g_attrib_unref(gas->attrib);
gas->attrib = NULL;
}
--
1.7.8.6
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