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extmod/btstack: Add support for CCCD to allow client subscriptions. 

This allows gatts_write(..., send_update=True) to work, which will send
notifications/indications to subscribed clients.

btstack already created the CCCD but writes to it were ignored.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This commit is contained in:
Jim Mussared 2023-03-10 00:56:31 +11:00
parent f9b60a240a
commit bb4ee06d98
2 changed files with 52 additions and 9 deletions
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59
extmod/btstack/modbluetooth_btstack.c
View File

@ -935,7 +935,11 @@ STATIC int att_write_callback(hci_con_handle_t connection_handle, uint16_t att_h
entry->data_len = MIN(entry->data_alloc, buffer_size + append_offset);
memcpy(entry->data + append_offset, buffer, entry->data_len - append_offset);
mp_bluetooth_gatts_on_write(connection_handle, att_handle);
uint16_t handle_uuid = att_uuid_for_handle(att_handle);
if (handle_uuid != GATT_CLIENT_CHARACTERISTICS_CONFIGURATION) {
// Suppress the Python callback for writes to the CCCD.
mp_bluetooth_gatts_on_write(connection_handle, att_handle);
}
return 0;
}
@ -987,7 +991,7 @@ int mp_bluetooth_gatts_register_service(mp_obj_bluetooth_uuid_t *service_uuid, m
size_t handle_index = 0;
size_t descriptor_index = 0;
static uint8_t cccb_buf[2] = {0};
static uint8_t cccd_buf[2] = {0};
for (size_t i = 0; i < num_characteristics; ++i) {
uint16_t props = (characteristic_flags[i] & 0x7f) | ATT_PROPERTY_DYNAMIC;
@ -1003,11 +1007,11 @@ int mp_bluetooth_gatts_register_service(mp_obj_bluetooth_uuid_t *service_uuid, m
return MP_EINVAL;
}
mp_bluetooth_gatts_db_create_entry(MP_STATE_PORT(bluetooth_btstack_root_pointers)->gatts_db, handles[handle_index], MP_BLUETOOTH_DEFAULT_ATTR_LEN);
// If a NOTIFY or INDICATE characteristic is added, then we need to manage a value for the CCCB.
// If a NOTIFY or INDICATE characteristic is added, then we need to manage a value for the CCCD.
if (props & (ATT_PROPERTY_NOTIFY | ATT_PROPERTY_INDICATE)) {
// btstack creates the CCCB as the next handle.
mp_bluetooth_gatts_db_create_entry(MP_STATE_PORT(bluetooth_btstack_root_pointers)->gatts_db, handles[handle_index] + 1, MP_BLUETOOTH_CCCB_LEN);
int ret = mp_bluetooth_gatts_db_write(MP_STATE_PORT(bluetooth_btstack_root_pointers)->gatts_db, handles[handle_index] + 1, cccb_buf, sizeof(cccb_buf));
// btstack automatically creates the CCCD as the next handle if the notify or indicate properties are set.
mp_bluetooth_gatts_db_create_entry(MP_STATE_PORT(bluetooth_btstack_root_pointers)->gatts_db, handles[handle_index] + 1, MP_BLUETOOTH_CCCD_LEN);
int ret = mp_bluetooth_gatts_db_write(MP_STATE_PORT(bluetooth_btstack_root_pointers)->gatts_db, handles[handle_index] + 1, cccd_buf, sizeof(cccd_buf));
if (ret) {
return ret;
}
@ -1058,9 +1062,48 @@ int mp_bluetooth_gatts_write(uint16_t value_handle, const uint8_t *value, size_t
return ERRNO_BLUETOOTH_NOT_ACTIVE;
}
if (send_update) {
return MP_EOPNOTSUPP;
DEBUG_printf(" --> send_update\n");
// If a characteristic has notify or indicate set, then btstack automatically creates the CCCD as the next handle.
// So if the next handle is a CCCD, then this characteristic must have had notify/indicate set.
uint16_t next_handle_uuid = att_uuid_for_handle(value_handle + 1);
if (next_handle_uuid != GATT_CLIENT_CHARACTERISTICS_CONFIGURATION) {
return MP_EINVAL;
}
DEBUG_printf(" --> got handle for cccd: %d\n", value_handle + 1);
}
return mp_bluetooth_gatts_db_write(MP_STATE_PORT(bluetooth_btstack_root_pointers)->gatts_db, value_handle, value, value_len);
int err = mp_bluetooth_gatts_db_write(MP_STATE_PORT(bluetooth_btstack_root_pointers)->gatts_db, value_handle, value, value_len);
if (!send_update || err) {
return err;
}
// Read the CCCD value. TODO: These should be per-connection.
const uint8_t *cccd;
size_t cccd_len;
err = mp_bluetooth_gatts_db_read(MP_STATE_PORT(bluetooth_btstack_root_pointers)->gatts_db, value_handle + 1, &cccd, &cccd_len);
if (cccd_len != 2 || err) {
return err;
}
// Notify/indicate all active connections.
btstack_linked_list_iterator_t it;
hci_connections_get_iterator(&it);
while (btstack_linked_list_iterator_has_next(&it)) {
hci_connection_t *connection = (hci_connection_t *)btstack_linked_list_iterator_next(&it);
if (cccd[0] & 1) {
err = mp_bluetooth_gatts_notify_indicate(connection->con_handle, value_handle, MP_BLUETOOTH_GATTS_OP_NOTIFY, value, value_len);
if (err) {
return err;
}
}
if (cccd[0] & 2) {
err = mp_bluetooth_gatts_notify_indicate(connection->con_handle, value_handle, MP_BLUETOOTH_GATTS_OP_INDICATE, value, value_len);
if (err) {
return err;
}
}
}
return 0;
}
#if !MICROPY_TRACKED_ALLOC

2
extmod/modbluetooth.h
View File

@ -84,7 +84,7 @@
#define MP_BLUETOOTH_DEFAULT_ATTR_LEN (20)
#endif
#define MP_BLUETOOTH_CCCB_LEN (2)
#define MP_BLUETOOTH_CCCD_LEN (2)
// Advertisement packet lengths
#define MP_BLUETOOTH_GAP_ADV_MAX_LEN (32)