int att_server_notify(uint16_t handle, uint8_t *value, uint16_t value_len){
if (!l2cap_can_send_fixed_channel_packet_now(att_connection.con_handle)) return BTSTACK_ACL_BUFFERS_FULL;
l2cap_reserve_packet_buffer();
uint8_t * packet_buffer = l2cap_get_outgoing_buffer();
uint16_t size = att_prepare_handle_value_notification(&att_connection, handle, value, value_len, packet_buffer);
return l2cap_send_prepared_connectionless(att_connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size);
}
int att_server_notify(hci_con_handle_t con_handle, uint16_t attribute_handle, uint8_t *value, uint16_t value_len){
att_server_t * att_server = att_server_for_handle(con_handle);
if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
if (!att_dispatch_server_can_send_now(con_handle)) return BTSTACK_ACL_BUFFERS_FULL;
l2cap_reserve_packet_buffer();
uint8_t * packet_buffer = l2cap_get_outgoing_buffer();
uint16_t size = att_prepare_handle_value_notification(&att_server->connection, attribute_handle, value, value_len, packet_buffer);
return l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size);
}
void send_ucd_packet(void){
l2cap_reserve_packet_buffer();
int ucd_size = 50;
uint8_t * ucd_buffer = l2cap_get_outgoing_buffer();
bt_store_16(ucd_buffer, 0, 0x2211);
int i;
for (i=2; i< ucd_size ; i++){
ucd_buffer[i] = i;
}
l2cap_send_prepared_connectionless(handle, L2CAP_CID_CONNECTIONLESS_CHANNEL, ucd_size);
}
// pre: att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED
// pre: can send now
// returns: 1 if packet was sent
static int att_server_process_validated_request(att_server_t * att_server){
l2cap_reserve_packet_buffer();
uint8_t * att_response_buffer = l2cap_get_outgoing_buffer();
uint16_t att_response_size = att_handle_request(&att_server->connection, att_server->request_buffer, att_server->request_size, att_response_buffer);
#ifdef ENABLE_ATT_DELAYED_READ_RESPONSE
if (att_response_size == ATT_READ_RESPONSE_PENDING){
// update state
att_server->state = ATT_SERVER_READ_RESPONSE_PENDING;
// callback with handle ATT_READ_RESPONSE_PENDING
att_server_client_read_callback(att_server->connection.con_handle, ATT_READ_RESPONSE_PENDING, 0, NULL, 0);
// free reserved buffer
l2cap_release_packet_buffer();
return 0;
}
#endif
// intercept "insufficient authorization" for authenticated connections to allow for user authorization
if ((att_response_size >= 4)
&& (att_response_buffer[0] == ATT_ERROR_RESPONSE)
&& (att_response_buffer[4] == ATT_ERROR_INSUFFICIENT_AUTHORIZATION)
&& (att_server->connection.authenticated)){
switch (gap_authorization_state(att_server->connection.con_handle)){
case AUTHORIZATION_UNKNOWN:
l2cap_release_packet_buffer();
sm_request_pairing(att_server->connection.con_handle);
return 0;
case AUTHORIZATION_PENDING:
l2cap_release_packet_buffer();
return 0;
default:
break;
}
}
att_server->state = ATT_SERVER_IDLE;
if (att_response_size == 0) {
l2cap_release_packet_buffer();
return 0;
}
l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, att_response_size);
// notify client about MTU exchange result
if (att_response_buffer[0] == ATT_EXCHANGE_MTU_RESPONSE){
att_emit_mtu_event(att_server->connection.con_handle, att_server->connection.mtu);
}
return 1;
}
int l2cap_send_connectionless(uint16_t handle, uint16_t cid, uint8_t *data, uint16_t len){
if (!hci_can_send_packet_now(HCI_ACL_DATA_PACKET)){
log_info("l2cap_send_internal cid %u, cannot send\n", cid);
return BTSTACK_ACL_BUFFERS_FULL;
}
uint8_t *acl_buffer = hci_get_outgoing_acl_packet_buffer();
memcpy(&acl_buffer[8], data, len);
return l2cap_send_prepared_connectionless(handle, cid, len);
}
int att_server_indicate(uint16_t handle, uint8_t *value, uint16_t value_len){
if (att_handle_value_indication_handle) return ATT_HANDLE_VALUE_INDICATION_IN_PORGRESS;
if (!l2cap_can_send_fixed_channel_packet_now(att_connection.con_handle)) return BTSTACK_ACL_BUFFERS_FULL;
// track indication
att_handle_value_indication_handle = handle;
run_loop_set_timer_handler(&att_handle_value_indication_timer, att_handle_value_indication_timeout);
run_loop_set_timer(&att_handle_value_indication_timer, ATT_TRANSACTION_TIMEOUT_MS);
run_loop_add_timer(&att_handle_value_indication_timer);
l2cap_reserve_packet_buffer();
uint8_t * packet_buffer = l2cap_get_outgoing_buffer();
uint16_t size = att_prepare_handle_value_indication(&att_connection, handle, value, value_len, packet_buffer);
l2cap_send_prepared_connectionless(att_connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size);
return 0;
}
int att_server_indicate(hci_con_handle_t con_handle, uint16_t attribute_handle, uint8_t *value, uint16_t value_len){
att_server_t * att_server = att_server_for_handle(con_handle);
if (!att_server) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
if (att_server->value_indication_handle) return ATT_HANDLE_VALUE_INDICATION_IN_PROGRESS;
if (!att_dispatch_server_can_send_now(con_handle)) return BTSTACK_ACL_BUFFERS_FULL;
// track indication
att_server->value_indication_handle = attribute_handle;
btstack_run_loop_set_timer_handler(&att_server->value_indication_timer, att_handle_value_indication_timeout);
btstack_run_loop_set_timer(&att_server->value_indication_timer, ATT_TRANSACTION_TIMEOUT_MS);
btstack_run_loop_add_timer(&att_server->value_indication_timer);
l2cap_reserve_packet_buffer();
uint8_t * packet_buffer = l2cap_get_outgoing_buffer();
uint16_t size = att_prepare_handle_value_indication(&att_server->connection, attribute_handle, value, value_len, packet_buffer);
l2cap_send_prepared_connectionless(att_server->connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size);
return 0;
}
static void att_run(void){
switch (att_server_state){
case ATT_SERVER_IDLE:
case ATT_SERVER_W4_SIGNED_WRITE_VALIDATION:
return;
case ATT_SERVER_REQUEST_RECEIVED:
if (att_request_buffer[0] == ATT_SIGNED_WRITE_COMMAND){
log_info("ATT Signed Write!");
if (!sm_cmac_ready()) {
log_info("ATT Signed Write, sm_cmac engine not ready. Abort");
att_server_state = ATT_SERVER_IDLE;
return;
}
if (att_request_size < (3 + 12)) {
log_info("ATT Signed Write, request to short. Abort.");
att_server_state = ATT_SERVER_IDLE;
return;
}
if (att_ir_lookup_active){
return;
}
if (att_ir_le_device_db_index < 0){
log_info("ATT Signed Write, CSRK not available");
att_server_state = ATT_SERVER_IDLE;
return;
}
// check counter
uint32_t counter_packet = READ_BT_32(att_request_buffer, att_request_size-12);
uint32_t counter_db = le_device_db_remote_counter_get(att_ir_le_device_db_index);
log_info("ATT Signed Write, DB counter %u, packet counter %u", counter_db, counter_packet);
if (counter_packet < counter_db){
log_info("ATT Signed Write, db reports higher counter, abort");
att_server_state = ATT_SERVER_IDLE;
return;
}
// signature is { sequence counter, secure hash }
sm_key_t csrk;
le_device_db_csrk_get(att_ir_le_device_db_index, csrk);
att_server_state = ATT_SERVER_W4_SIGNED_WRITE_VALIDATION;
log_info("Orig Signature: ");
hexdump( &att_request_buffer[att_request_size-8], 8);
sm_cmac_start(csrk, att_request_size - 12, att_request_buffer, counter_packet, att_signed_write_handle_cmac_result);
return;
}
// NOTE: fall through for regular commands
case ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED:
if (!l2cap_can_send_fixed_channel_packet_now(att_connection.con_handle)) return;
l2cap_reserve_packet_buffer();
uint8_t * att_response_buffer = l2cap_get_outgoing_buffer();
uint16_t att_response_size = att_handle_request(&att_connection, att_request_buffer, att_request_size, att_response_buffer);
// intercept "insufficient authorization" for authenticated connections to allow for user authorization
if ((att_response_size >= 4)
&& (att_response_buffer[0] == ATT_ERROR_RESPONSE)
&& (att_response_buffer[4] == ATT_ERROR_INSUFFICIENT_AUTHORIZATION)
&& (att_connection.authenticated)){
switch (sm_authorization_state(att_client_addr_type, att_client_address)){
case AUTHORIZATION_UNKNOWN:
l2cap_release_packet_buffer();
sm_request_authorization(att_client_addr_type, att_client_address);
return;
case AUTHORIZATION_PENDING:
l2cap_release_packet_buffer();
return;
default:
break;
}
}
att_server_state = ATT_SERVER_IDLE;
if (att_response_size == 0) {
l2cap_release_packet_buffer();
return;
}
l2cap_send_prepared_connectionless(att_connection.con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, att_response_size);
// notify client about MTU exchange result
if (att_response_buffer[0] == ATT_EXCHANGE_MTU_RESPONSE){
att_emit_mtu_event(att_connection.con_handle, att_connection.mtu);
}
break;
}
}