This patch makes CCC writes via bt_gatt_client_register_notify
cancellable. The following changes have been introduced:
1. bt_gatt_client_register_notify now returns the id immediately
instead of returning it in a callback. The callback is still
used to communicate ATT protocol errors.
2. A notify callback is immediately registered, so that if the
remote end sends any ATT notifications/indications, the caller
will start receiving them right away.
---
src/shared/gatt-client.c | 116 +++++++++++++++++++++++++++--------------------
src/shared/gatt-client.h | 7 ++-
tools/btgatt-client.c | 17 ++++---
3 files changed, 79 insertions(+), 61 deletions(-)
diff --git a/src/shared/gatt-client.c b/src/shared/gatt-client.c
index 04fb4cb..66d0b63 100644
--- a/src/shared/gatt-client.c
+++ b/src/shared/gatt-client.c
@@ -168,9 +168,10 @@ struct notify_data {
struct bt_gatt_client *client;
bool invalid;
unsigned int id;
+ unsigned int att_id;
int ref_count;
struct notify_chrc *chrc;
- bt_gatt_client_notify_id_callback_t callback;
+ bt_gatt_client_register_callback_t callback;
bt_gatt_client_notify_callback_t notify;
void *user_data;
bt_gatt_client_destroy_func_t destroy;
@@ -1011,22 +1012,20 @@ struct service_changed_op {
uint16_t end_handle;
};
-static void service_changed_reregister_cb(unsigned int id, uint16_t att_ecode,
- void *user_data)
+static void service_changed_reregister_cb(uint16_t att_ecode, void *user_data)
{
struct bt_gatt_client *client = user_data;
- if (!id || att_ecode) {
+ if (!att_ecode) {
util_debug(client->debug_callback, client->debug_data,
- "Failed to register handler for \"Service Changed\"");
+ "Re-registered handler for \"Service Changed\" after "
+ "change in GATT service");
return;
}
- client->svc_chngd_ind_id = id;
-
util_debug(client->debug_callback, client->debug_data,
- "Re-registered handler for \"Service Changed\" after change in "
- "GATT service");
+ "Failed to register handler for \"Service Changed\"");
+ client->svc_chngd_ind_id = 0;
}
static void process_service_changed(struct bt_gatt_client *client,
@@ -1090,11 +1089,12 @@ static void service_changed_complete(struct discovery_op *op, bool success,
/* The GATT service was modified. Re-register the handler for
* indications from the "Service Changed" characteristic.
*/
- if (bt_gatt_client_register_notify(client,
+ client->svc_chngd_ind_id = bt_gatt_client_register_notify(client,
gatt_db_attribute_get_handle(attr),
service_changed_reregister_cb,
service_changed_cb,
- client, NULL))
+ client, NULL);
+ if (client->svc_chngd_ind_id)
return;
util_debug(client->debug_callback, client->debug_data,
@@ -1184,24 +1184,24 @@ static void service_changed_cb(uint16_t value_handle, const uint8_t *value,
queue_push_tail(client->svc_chngd_queue, op);
}
-static void service_changed_register_cb(unsigned int id, uint16_t att_ecode,
- void *user_data)
+static void service_changed_register_cb(uint16_t att_ecode, void *user_data)
{
bool success;
struct bt_gatt_client *client = user_data;
- if (!id || att_ecode) {
+ if (att_ecode) {
util_debug(client->debug_callback, client->debug_data,
"Failed to register handler for \"Service Changed\"");
success = false;
+ client->svc_chngd_ind_id = 0;
goto done;
}
- client->svc_chngd_ind_id = id;
client->ready = true;
success = true;
util_debug(client->debug_callback, client->debug_data,
- "Registered handler for \"Service Changed\": %u", id);
+ "Registered handler for \"Service Changed\": %u",
+ client->svc_chngd_ind_id);
done:
notify_client_ready(client, success, att_ecode);
@@ -1211,7 +1211,6 @@ static void init_complete(struct discovery_op *op, bool success,
uint8_t att_ecode)
{
struct bt_gatt_client *client = op->client;
- bool registered;
struct gatt_db_attribute *attr = NULL;
bt_uuid_t uuid;
@@ -1235,14 +1234,14 @@ static void init_complete(struct discovery_op *op, bool success,
* the handler using the existing framework.
*/
client->ready = true;
- registered = bt_gatt_client_register_notify(client,
+ client->svc_chngd_ind_id = bt_gatt_client_register_notify(client,
gatt_db_attribute_get_handle(attr),
service_changed_register_cb,
service_changed_cb,
client, NULL);
client->ready = false;
- if (registered)
+ if (client->svc_chngd_ind_id)
return;
util_debug(client->debug_callback, client->debug_data,
@@ -1301,24 +1300,15 @@ static void complete_notify_request(void *data)
/* Increment the per-characteristic ref count of notify handlers */
__sync_fetch_and_add(¬ify_data->chrc->notify_count, 1);
- /* Add the handler to the bt_gatt_client's general list */
- queue_push_tail(notify_data->client->notify_list,
- notify_data_ref(notify_data));
-
- /* Assign an ID to the handler and notify the caller that it was
- * successfully registered.
- */
- if (notify_data->client->next_reg_id < 1)
- notify_data->client->next_reg_id = 1;
-
- notify_data->id = notify_data->client->next_reg_id++;
- notify_data->callback(notify_data->id, 0, notify_data->user_data);
+ notify_data->att_id = 0;
+ notify_data->callback(0, notify_data->user_data);
}
static bool notify_data_write_ccc(struct notify_data *notify_data, bool enable,
bt_att_response_func_t callback)
{
uint8_t pdu[4];
+ unsigned int att_id;
assert(notify_data->chrc->ccc_handle);
memset(pdu, 0, sizeof(pdu));
@@ -1338,13 +1328,13 @@ static bool notify_data_write_ccc(struct notify_data *notify_data, bool enable,
return false;
}
- notify_data->chrc->ccc_write_id = bt_att_send(notify_data->client->att,
- BT_ATT_OP_WRITE_REQ,
- pdu, sizeof(pdu),
- callback,
- notify_data, notify_data_unref);
+ att_id = bt_att_send(notify_data->client->att, BT_ATT_OP_WRITE_REQ,
+ pdu, sizeof(pdu), callback,
+ notify_data_ref(notify_data),
+ notify_data_unref);
+ notify_data->chrc->ccc_write_id = notify_data->att_id = att_id;
- return !!notify_data->chrc->ccc_write_id;
+ return !!att_id;
}
static uint8_t process_error(const void *pdu, uint16_t length)
@@ -1377,7 +1367,8 @@ static void enable_ccc_callback(uint8_t opcode, const void *pdu,
* the next one in the queue. If there was an error sending the
* write request, then just move on to the next queued entry.
*/
- notify_data->callback(0, att_ecode, notify_data->user_data);
+ queue_remove(notify_data->client->notify_list, notify_data);
+ notify_data->callback(att_ecode, notify_data->user_data);
while ((notify_data = queue_pop_head(
notify_data->chrc->reg_notify_queue))) {
@@ -1426,6 +1417,16 @@ static void complete_unregister_notify(void *data)
{
struct notify_data *notify_data = data;
+ /*
+ * If a procedure to enable the CCC is still pending, then cancel it and
+ * return.
+ */
+ if (notify_data->att_id) {
+ bt_att_cancel(notify_data->client->att, notify_data->att_id);
+ notify_data_unref(notify_data);
+ return;
+ }
+
if (__sync_sub_and_fetch(¬ify_data->chrc->notify_count, 1)) {
notify_data_unref(notify_data);
return;
@@ -1449,6 +1450,10 @@ static void notify_handler(void *data, void *user_data)
if (pdu_data->length > 2)
value = pdu_data->pdu + 2;
+ /*
+ * Even if the notify data has a pending ATT request to write to the
+ * CCC, there is really no reason not to notify the handlers.
+ */
if (notify_data->notify)
notify_data->notify(value_handle, value, pdu_data->length - 2,
notify_data->user_data);
@@ -2569,9 +2574,9 @@ static bool match_notify_chrc_value_handle(const void *a, const void *b)
return chrc->value_handle == value_handle;
}
-bool bt_gatt_client_register_notify(struct bt_gatt_client *client,
+unsigned int bt_gatt_client_register_notify(struct bt_gatt_client *client,
uint16_t chrc_value_handle,
- bt_gatt_client_notify_id_callback_t callback,
+ bt_gatt_client_register_callback_t callback,
bt_gatt_client_notify_callback_t notify,
void *user_data,
bt_gatt_client_destroy_func_t destroy)
@@ -2580,10 +2585,10 @@ bool bt_gatt_client_register_notify(struct bt_gatt_client *client,
struct notify_chrc *chrc = NULL;
if (!client || !client->db || !chrc_value_handle || !callback)
- return false;
+ return 0;
if (!bt_gatt_client_is_ready(client) || client->in_svc_chngd)
- return false;
+ return 0;
/* Check if a characteristic ref count has been started already */
chrc = queue_find(client->notify_chrcs, match_notify_chrc_value_handle,
@@ -2596,17 +2601,16 @@ bool bt_gatt_client_register_notify(struct bt_gatt_client *client,
*/
chrc = notify_chrc_create(client, chrc_value_handle);
if (!chrc)
- return false;
-
+ return 0;
}
/* Fail if we've hit the maximum allowed notify sessions */
if (chrc->notify_count == INT_MAX)
- return false;
+ return 0;
notify_data = new0(struct notify_data, 1);
if (!notify_data)
- return false;
+ return 0;
notify_data->client = client;
notify_data->ref_count = 1;
@@ -2616,13 +2620,24 @@ bool bt_gatt_client_register_notify(struct bt_gatt_client *client,
notify_data->user_data = user_data;
notify_data->destroy = destroy;
+ /* Add the handler to the bt_gatt_client's general list */
+ queue_push_tail(client->notify_list, notify_data);
+
+ /* Assign an ID to the handler and notify the caller that it was
+ * successfully registered.
+ */
+ if (client->next_reg_id < 1)
+ client->next_reg_id = 1;
+
+ notify_data->id = client->next_reg_id++;
+
/*
* If a write to the CCC descriptor is in progress, then queue this
* request.
*/
if (chrc->ccc_write_id) {
queue_push_tail(chrc->reg_notify_queue, notify_data);
- return true;
+ return notify_data->id;
}
/*
@@ -2630,16 +2645,17 @@ bool bt_gatt_client_register_notify(struct bt_gatt_client *client,
*/
if (chrc->notify_count > 0) {
complete_notify_request(notify_data);
- return true;
+ return notify_data->id;
}
/* Write to the CCC descriptor */
if (!notify_data_write_ccc(notify_data, true, enable_ccc_callback)) {
+ queue_remove(client->notify_list, notify_data);
free(notify_data);
- return false;
+ return 0;
}
- return true;
+ return notify_data->id;
}
bool bt_gatt_client_unregister_notify(struct bt_gatt_client *client,
diff --git a/src/shared/gatt-client.h b/src/shared/gatt-client.h
index 9a00feb..b84fa13 100644
--- a/src/shared/gatt-client.h
+++ b/src/shared/gatt-client.h
@@ -49,8 +49,7 @@ typedef void (*bt_gatt_client_write_long_callback_t)(bool success,
typedef void (*bt_gatt_client_notify_callback_t)(uint16_t value_handle,
const uint8_t *value, uint16_t length,
void *user_data);
-typedef void (*bt_gatt_client_notify_id_callback_t)(unsigned int id,
- uint16_t att_ecode,
+typedef void (*bt_gatt_client_register_callback_t)(uint16_t att_ecode,
void *user_data);
typedef void (*bt_gatt_client_service_changed_callback_t)(uint16_t start_handle,
uint16_t end_handle,
@@ -110,9 +109,9 @@ unsigned int bt_gatt_client_write_long_value(struct bt_gatt_client *client,
void *user_data,
bt_gatt_client_destroy_func_t destroy);
-bool bt_gatt_client_register_notify(struct bt_gatt_client *client,
+unsigned int bt_gatt_client_register_notify(struct bt_gatt_client *client,
uint16_t chrc_value_handle,
- bt_gatt_client_notify_id_callback_t callback,
+ bt_gatt_client_register_callback_t callback,
bt_gatt_client_notify_callback_t notify,
void *user_data,
bt_gatt_client_destroy_func_t destroy);
diff --git a/tools/btgatt-client.c b/tools/btgatt-client.c
index 62c4d3e..8bda89b 100644
--- a/tools/btgatt-client.c
+++ b/tools/btgatt-client.c
@@ -856,16 +856,15 @@ static void notify_cb(uint16_t value_handle, const uint8_t *value,
PRLOG("\n");
}
-static void register_notify_cb(unsigned int id, uint16_t att_ecode,
- void *user_data)
+static void register_notify_cb(uint16_t att_ecode, void *user_data)
{
- if (!id) {
+ if (att_ecode) {
PRLOG("Failed to register notify handler "
"- error code: 0x%02x\n", att_ecode);
return;
}
- PRLOG("Registered notify handler with id: %u\n", id);
+ PRLOG("Registered notify handler!");
}
static void cmd_register_notify(struct client *cli, char *cmd_str)
@@ -873,6 +872,7 @@ static void cmd_register_notify(struct client *cli, char *cmd_str)
char *argv[2];
int argc = 0;
uint16_t value_handle;
+ unsigned int id;
char *endptr = NULL;
if (!bt_gatt_client_is_ready(cli->gatt)) {
@@ -891,12 +891,15 @@ static void cmd_register_notify(struct client *cli, char *cmd_str)
return;
}
- if (!bt_gatt_client_register_notify(cli->gatt, value_handle,
+ id = bt_gatt_client_register_notify(cli->gatt, value_handle,
register_notify_cb,
- notify_cb, NULL, NULL))
+ notify_cb, NULL, NULL);
+ if (!id) {
printf("Failed to register notify handler\n");
+ return;
+ }
- printf("\n");
+ PRLOG("Registering notify handler with id: %u\n", id);
}
static void unregister_notify_usage(void)
--
2.2.0.rc0.207.ga3a616c
--
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