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/*
* Copyright (C) 2014 BlueKitchen GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* 4. Any redistribution, use, or modification is done solely for
* personal benefit and not for any commercial purpose or for
* monetary gain.
*
* THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
* GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Please inquire about commercial licensing options at
* contact@bluekitchen-gmbh.com
*
*/
#define BTSTACK_FILE__ "att_server.c"
//
// ATT Server Globals
//
#include <stdint.h>
#include <string.h>
#include <inttypes.h>
#include "btstack_config.h"
#include "ble/att_dispatch.h"
#include "ble/att_db.h"
#include "ble/att_server.h"
#include "ble/core.h"
#include "ble/le_device_db.h"
#include "ble/sm.h"
#include "btstack_debug.h"
#include "btstack_event.h"
#include "btstack_memory.h"
#include "btstack_run_loop.h"
#include "gap.h"
#include "hci.h"
#include "hci_dump.h"
#include "l2cap.h"
#include "btstack_tlv.h"
#ifdef ENABLE_LE_SIGNED_WRITE
#include "ble/sm.h"
#include "bluetooth_psm.h"
#endif
#ifdef ENABLE_TESTING_SUPPORT
#include <stdio.h>
#endif
#ifndef NVN_NUM_GATT_SERVER_CCC
#define NVN_NUM_GATT_SERVER_CCC 20
#endif
#define ATT_SERVICE_FLAGS_DELAYED_RESPONSE (1<<0u)
static void att_run_for_context(att_server_t * att_server, att_connection_t * att_connection);
static att_write_callback_t att_server_write_callback_for_handle(uint16_t handle);
static btstack_packet_handler_t att_server_packet_handler_for_handle(uint16_t handle);
static void att_server_handle_can_send_now(void);
static void att_server_persistent_ccc_restore(att_server_t * att_server, att_connection_t * att_connection);
static void att_server_persistent_ccc_clear(att_server_t * att_server);
static void att_server_handle_att_pdu(att_server_t * att_server, att_connection_t * att_connection, uint8_t * packet, uint16_t size);
typedef enum {
ATT_SERVER_RUN_PHASE_1_REQUESTS = 0,
ATT_SERVER_RUN_PHASE_2_INDICATIONS,
ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS,
} att_server_run_phase_t;
//
typedef struct {
uint32_t seq_nr;
uint16_t att_handle;
uint8_t value;
uint8_t device_index;
} persistent_ccc_entry_t;
// global
static btstack_packet_callback_registration_t hci_event_callback_registration;
static btstack_packet_callback_registration_t sm_event_callback_registration;
static btstack_packet_handler_t att_client_packet_handler;
static btstack_linked_list_t service_handlers;
static btstack_context_callback_registration_t att_client_waiting_for_can_send_registration;
static att_read_callback_t att_server_client_read_callback;
static att_write_callback_t att_server_client_write_callback;
// round robin
static hci_con_handle_t att_server_last_can_send_now = HCI_CON_HANDLE_INVALID;
static uint8_t att_server_flags;
#ifdef ENABLE_GATT_OVER_EATT
typedef struct {
btstack_linked_item_t item;
att_server_t att_server;
att_connection_t att_connection;
uint8_t * receive_buffer;
uint8_t * send_buffer;
} att_server_eatt_bearer_t;
static att_server_eatt_bearer_t * att_server_eatt_bearer_for_con_handle(hci_con_handle_t con_handle);
static btstack_linked_list_t att_server_eatt_bearer_pool;
static btstack_linked_list_t att_server_eatt_bearer_active;
#endif
#ifdef ENABLE_LE_SIGNED_WRITE
static bool att_server_connections_for_state(att_server_state_t state, att_server_t ** att_server_out, att_connection_t ** att_connection_out){
btstack_linked_list_iterator_t it;
hci_connections_get_iterator(&it);
while(btstack_linked_list_iterator_has_next(&it)){
hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
if (hci_connection->att_server.state == state) {
*att_server_out = &hci_connection->att_server;
*att_connection_out = &hci_connection->att_connection;
return true;
}
}
#ifdef ENABLE_GATT_OVER_EATT
btstack_linked_list_iterator_init(&it, &att_server_eatt_bearer_active);
while(btstack_linked_list_iterator_has_next(&it)){
att_server_eatt_bearer_t * eatt_bearer = (att_server_eatt_bearer_t *) btstack_linked_list_iterator_next(&it);
if (eatt_bearer->att_server.state == state) {
*att_server_out = &eatt_bearer->att_server;
*att_connection_out = &eatt_bearer->att_connection;
return true;
}
}
#endif
return false;
}
#endif
static void att_server_request_can_send_now(att_server_t * att_server, att_connection_t * att_connection ){
switch (att_server->bearer_type){
case ATT_BEARER_UNENHANCED_LE:
#ifdef ENABLE_GATT_OVER_CLASSIC
case ATT_BEARER_UNENHANCED_CLASSIC:
/* fall through */
#endif
att_dispatch_server_request_can_send_now_event(att_connection->con_handle);
break;
#ifdef ENABLE_GATT_OVER_EATT
case ATT_BEARER_ENHANCED_LE:
l2cap_request_can_send_now_event(att_server->l2cap_cid);
break;
#endif
default:
btstack_unreachable();
break;
}
}
static bool att_server_can_send_packet(att_server_t * att_server, att_connection_t * att_connection){
switch (att_server->bearer_type) {
case ATT_BEARER_UNENHANCED_LE:
#ifdef ENABLE_GATT_OVER_CLASSIC
case ATT_BEARER_UNENHANCED_CLASSIC:
/* fall through */
#endif
return att_dispatch_server_can_send_now(att_connection->con_handle);
#ifdef ENABLE_GATT_OVER_EATT
case ATT_BEARER_ENHANCED_LE:
return l2cap_can_send_packet_now(att_server->l2cap_cid);
#endif
default:
btstack_unreachable();
break;
}
return false;
}
static void att_handle_value_indication_notify_client(uint8_t status, uint16_t client_handle, uint16_t attribute_handle){
btstack_packet_handler_t packet_handler = att_server_packet_handler_for_handle(attribute_handle);
if (!packet_handler) return;
uint8_t event[7];
int pos = 0;
event[pos++] = ATT_EVENT_HANDLE_VALUE_INDICATION_COMPLETE;
event[pos++] = sizeof(event) - 2u;
event[pos++] = status;
little_endian_store_16(event, pos, client_handle);
pos += 2;
little_endian_store_16(event, pos, attribute_handle);
(*packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event));
}
static void att_emit_event_to_all(const uint8_t * event, uint16_t size){
// dispatch to app level handler
if (att_client_packet_handler != NULL){
(*att_client_packet_handler)(HCI_EVENT_PACKET, 0, (uint8_t*) event, size);
}
// dispatch to service handlers
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &service_handlers);
while (btstack_linked_list_iterator_has_next(&it)){
att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it);
if (!handler->packet_handler) continue;
(*handler->packet_handler)(HCI_EVENT_PACKET, 0, (uint8_t*) event, size);
}
}
static void att_emit_mtu_event(hci_con_handle_t con_handle, uint16_t mtu){
uint8_t event[6];
int pos = 0;
event[pos++] = ATT_EVENT_MTU_EXCHANGE_COMPLETE;
event[pos++] = sizeof(event) - 2u;
little_endian_store_16(event, pos, con_handle);
pos += 2;
little_endian_store_16(event, pos, mtu);
// also dispatch to GATT Clients
att_dispatch_server_mtu_exchanged(con_handle, mtu);
// dispatch to app level handler and service handlers
att_emit_event_to_all(&event[0], sizeof(event));
}
static void att_emit_can_send_now_event(void * context){
UNUSED(context);
if (!att_client_packet_handler) return;
uint8_t event[] = { ATT_EVENT_CAN_SEND_NOW, 0};
(*att_client_packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event));
}
static void att_emit_connected_event(att_server_t * att_server, att_connection_t * att_connection){
uint8_t event[11];
int pos = 0;
event[pos++] = ATT_EVENT_CONNECTED;
event[pos++] = sizeof(event) - 2u;
event[pos++] = att_server->peer_addr_type;
reverse_bd_addr(att_server->peer_address, &event[pos]);
pos += 6;
little_endian_store_16(event, pos, att_connection->con_handle);
pos += 2;
// dispatch to app level handler and service handlers
att_emit_event_to_all(&event[0], sizeof(event));
}
static void att_emit_disconnected_event(uint16_t con_handle){
uint8_t event[4];
int pos = 0;
event[pos++] = ATT_EVENT_DISCONNECTED;
event[pos++] = sizeof(event) - 2u;
little_endian_store_16(event, pos, con_handle);
pos += 2;
// dispatch to app level handler and service handlers
att_emit_event_to_all(&event[0], sizeof(event));
}
static void att_handle_value_indication_timeout(btstack_timer_source_t *ts){
void * context = btstack_run_loop_get_timer_context(ts);
hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) context;
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return;
// @note: after a transaction timeout, no more requests shall be sent over this ATT Bearer
// (that's why we don't reset the value_indication_handle)
att_server_t * att_server = &hci_connection->att_server;
uint16_t att_handle = att_server->value_indication_handle;
att_connection_t * att_connection = &hci_connection->att_connection;
att_handle_value_indication_notify_client((uint8_t)ATT_HANDLE_VALUE_INDICATION_TIMEOUT, att_connection->con_handle, att_handle);
}
static void att_server_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
UNUSED(channel); // ok: there is no channel
UNUSED(size); // ok: handling own l2cap events
att_server_t * att_server;
att_connection_t * att_connection;
hci_con_handle_t con_handle;
hci_connection_t * hci_connection;
switch (packet_type) {
case HCI_EVENT_PACKET:
switch (hci_event_packet_get_type(packet)) {
case HCI_EVENT_META_GAP:
switch (hci_event_gap_meta_get_subevent_code(packet)) {
case GAP_SUBEVENT_LE_CONNECTION_COMPLETE:
con_handle = gap_subevent_le_connection_complete_get_connection_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) break;
att_server = &hci_connection->att_server;
// store connection info
att_server->peer_addr_type = gap_subevent_le_connection_complete_get_peer_address_type(packet);
gap_subevent_le_connection_complete_get_peer_address(packet, att_server->peer_address);
att_connection = &hci_connection->att_connection;
att_connection->con_handle = con_handle;
// reset connection properties
att_server->state = ATT_SERVER_IDLE;
att_server->bearer_type = ATT_BEARER_UNENHANCED_LE;
att_connection->mtu = ATT_DEFAULT_MTU;
att_connection->max_mtu = l2cap_max_le_mtu();
if (att_connection->max_mtu > ATT_REQUEST_BUFFER_SIZE){
att_connection->max_mtu = ATT_REQUEST_BUFFER_SIZE;
}
att_connection->encryption_key_size = 0u;
att_connection->authenticated = 0u;
att_connection->authorized = 0u;
// workaround: identity resolving can already be complete, at least store result
att_server->ir_le_device_db_index = sm_le_device_index(con_handle);
att_server->ir_lookup_active = false;
att_server->pairing_active = false;
// notify all - new
att_emit_connected_event(att_server, att_connection);
break;
default:
break;
}
break;
case HCI_EVENT_LE_META:
switch (hci_event_le_meta_get_subevent_code(packet)) {
case HCI_SUBEVENT_LE_CONNECTION_COMPLETE:
// forward LE Connection Complete event to keep backward compatibility
// deprecated: please register hci handler with hci_add_event_handler or handle ATT_EVENT_CONNECTED
att_emit_event_to_all(packet, size);
break;
default:
break;
}
break;
case HCI_EVENT_ENCRYPTION_CHANGE:
case HCI_EVENT_ENCRYPTION_CHANGE_V2:
case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE:
// check handle
con_handle = little_endian_read_16(packet, 3);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) break;
if (gap_get_connection_type(con_handle) != GAP_CONNECTION_LE) break;
// update security params
att_server = &hci_connection->att_server;
att_connection = &hci_connection->att_connection;
att_connection->encryption_key_size = gap_encryption_key_size(con_handle);
att_connection->authenticated = gap_authenticated(con_handle) ? 1 : 0;
att_connection->secure_connection = gap_secure_connection(con_handle) ? 1 : 0;
log_info("encrypted key size %u, authenticated %u, secure connection %u",
att_connection->encryption_key_size, att_connection->authenticated, att_connection->secure_connection);
if (hci_event_packet_get_type(packet) == HCI_EVENT_ENCRYPTION_CHANGE){
// restore CCC values when encrypted for LE Connections
if (hci_event_encryption_change_get_encryption_enabled(packet) != 0){
att_server_persistent_ccc_restore(att_server, att_connection);
}
}
att_run_for_context(att_server, att_connection);
break;
case HCI_EVENT_DISCONNECTION_COMPLETE:
// check handle
con_handle = hci_event_disconnection_complete_get_connection_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) break;
att_server = &hci_connection->att_server;
att_connection = &hci_connection->att_connection;
att_clear_transaction_queue(att_connection);
att_connection->con_handle = 0;
att_server->pairing_active = false;
att_server->state = ATT_SERVER_IDLE;
if (att_server->value_indication_handle != 0u){
btstack_run_loop_remove_timer(&att_server->value_indication_timer);
uint16_t att_handle = att_server->value_indication_handle;
att_server->value_indication_handle = 0u; // reset error state
att_handle_value_indication_notify_client((uint8_t)ATT_HANDLE_VALUE_INDICATION_DISCONNECT, att_connection->con_handle, att_handle);
}
// notify all - new
att_emit_disconnected_event(con_handle);
// notify all - old
att_emit_event_to_all(packet, size);
break;
// Identity Resolving
case SM_EVENT_IDENTITY_RESOLVING_STARTED:
con_handle = sm_event_identity_resolving_started_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) break;
att_server = &hci_connection->att_server;
log_info("SM_EVENT_IDENTITY_RESOLVING_STARTED");
att_server->ir_lookup_active = true;
break;
case SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED:
con_handle = sm_event_identity_created_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return;
att_connection = &hci_connection->att_connection;
att_server = &hci_connection->att_server;
att_server->ir_lookup_active = false;
att_server->ir_le_device_db_index = sm_event_identity_resolving_succeeded_get_index(packet);
log_info("SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED");
att_run_for_context(att_server, att_connection);
break;
case SM_EVENT_IDENTITY_RESOLVING_FAILED:
con_handle = sm_event_identity_resolving_failed_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) break;
att_connection = &hci_connection->att_connection;
att_server = &hci_connection->att_server;
log_info("SM_EVENT_IDENTITY_RESOLVING_FAILED");
att_server->ir_lookup_active = false;
att_server->ir_le_device_db_index = -1;
att_run_for_context(att_server, att_connection);
break;
// Pairing started - delete stored CCC values
// - assumes pairing indicates either new device or re-pairing, in both cases there should be no stored CCC values
// - assumes that all events have the con handle as the first field
case SM_EVENT_JUST_WORKS_REQUEST:
case SM_EVENT_PASSKEY_DISPLAY_NUMBER:
case SM_EVENT_PASSKEY_INPUT_NUMBER:
case SM_EVENT_NUMERIC_COMPARISON_REQUEST:
con_handle = sm_event_just_works_request_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) break;
att_server = &hci_connection->att_server;
log_info("SM Pairing started");
att_server->pairing_active = true;
if (att_server->ir_le_device_db_index < 0) break;
att_server_persistent_ccc_clear(att_server);
// index not valid anymore
att_server->ir_le_device_db_index = -1;
break;
// Bonding completed
case SM_EVENT_IDENTITY_CREATED:
con_handle = sm_event_identity_created_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return;
att_connection = &hci_connection->att_connection;
att_server = &hci_connection->att_server;
att_server->pairing_active = false;
att_server->ir_le_device_db_index = sm_event_identity_created_get_index(packet);
att_run_for_context(att_server, att_connection);
break;
// Pairing complete (with/without bonding=storing of pairing information)
case SM_EVENT_PAIRING_COMPLETE:
con_handle = sm_event_pairing_complete_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return;
att_connection = &hci_connection->att_connection;
att_server = &hci_connection->att_server;
att_server->pairing_active = false;
att_run_for_context(att_server, att_connection);
break;
// Authorization
case SM_EVENT_AUTHORIZATION_RESULT: {
con_handle = sm_event_authorization_result_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) break;
att_connection = &hci_connection->att_connection;
att_server = &hci_connection->att_server;
att_connection->authorized = sm_event_authorization_result_get_authorization_result(packet);
att_server_request_can_send_now(att_server, att_connection);
break;
}
default:
break;
}
break;
default:
break;
}
}
static uint8_t
att_server_send_prepared(const att_server_t *att_server, const att_connection_t *att_connection, uint8_t *buffer,
uint16_t size) {
UNUSED(buffer);
uint8_t status = ERROR_CODE_SUCCESS;
switch (att_server->bearer_type) {
case ATT_BEARER_UNENHANCED_LE:
status = l2cap_send_prepared_connectionless(att_connection->con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, size);
break;
#ifdef ENABLE_GATT_OVER_CLASSIC
case ATT_BEARER_UNENHANCED_CLASSIC:
status = l2cap_send_prepared(att_server->l2cap_cid, size);
break;
#endif
#ifdef ENABLE_GATT_OVER_EATT
case ATT_BEARER_ENHANCED_LE:
btstack_assert(buffer != NULL);
status = l2cap_send(att_server->l2cap_cid, buffer, size);
break;
#endif
default:
btstack_unreachable();
break;
}
return status;
}
#ifdef ENABLE_LE_SIGNED_WRITE
static void att_signed_write_handle_cmac_result(uint8_t hash[8]){
att_server_t * att_server = NULL;
att_connection_t * att_connection = NULL;
bool found = att_server_connections_for_state(ATT_SERVER_W4_SIGNED_WRITE_VALIDATION, &att_server, &att_connection);
if (found == false){
return;
}
uint8_t hash_flipped[8];
reverse_64(hash, hash_flipped);
if (memcmp(hash_flipped, &att_server->request_buffer[att_server->request_size-8], 8) != 0){
log_info("ATT Signed Write, invalid signature");
#ifdef ENABLE_TESTING_SUPPORT
printf("ATT Signed Write, invalid signature\n");
#endif
att_server->state = ATT_SERVER_IDLE;
return;
}
log_info("ATT Signed Write, valid signature");
#ifdef ENABLE_TESTING_SUPPORT
printf("ATT Signed Write, valid signature\n");
#endif
// update sequence number
uint32_t counter_packet = little_endian_read_32(att_server->request_buffer, att_server->request_size-12);
le_device_db_remote_counter_set(att_server->ir_le_device_db_index, counter_packet+1);
att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED;
att_server_request_can_send_now(att_server, att_connection);
}
#endif
#ifdef ENABLE_ATT_DELAYED_RESPONSE
static void att_server_handle_response_pending(att_server_t *att_server, const att_connection_t *att_connection,
const uint8_t *eatt_buffer,
uint16_t att_response_size) {
// free reserved buffer
if (eatt_buffer == NULL){
l2cap_release_packet_buffer();
}
// update state
att_server->state = ATT_SERVER_RESPONSE_PENDING;
// callback with handle ATT_READ_RESPONSE_PENDING for reads
if (att_response_size == ATT_READ_RESPONSE_PENDING){
// notify services that returned response pending
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &service_handlers);
while (btstack_linked_list_iterator_has_next(&it)) {
att_service_handler_t *handler = (att_service_handler_t *) btstack_linked_list_iterator_next(&it);
if ((handler->flags & ATT_SERVICE_FLAGS_DELAYED_RESPONSE) != 0){
handler->flags &= ~ATT_SERVICE_FLAGS_DELAYED_RESPONSE;
handler->read_callback(att_connection->con_handle, ATT_READ_RESPONSE_PENDING, 0, NULL, 0);
}
}
// notify main read callback if it returned response pending
if ((att_server_flags & ATT_SERVICE_FLAGS_DELAYED_RESPONSE) != 0){
// flag was set by read callback
btstack_assert(att_server_client_read_callback != NULL);
(*att_server_client_read_callback)(att_connection->con_handle, ATT_READ_RESPONSE_PENDING, 0, NULL, 0);
}
}
}
#endif
// pre: att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED
// pre: can send now
// uses l2cap outgoing buffer if no eatt_buffer provided
// returns: 1 if packet was sent
static int
att_server_process_validated_request(att_server_t *att_server, att_connection_t *att_connection, uint8_t *eatt_buffer) {
uint8_t * att_response_buffer;
if (eatt_buffer != NULL){
att_response_buffer = eatt_buffer;
} else {
l2cap_reserve_packet_buffer();
att_response_buffer = l2cap_get_outgoing_buffer();
}
uint16_t att_response_size = 0;
// Send Error Response for MTU Request over connection-oriented channel
if ((att_server->bearer_type != ATT_BEARER_UNENHANCED_LE) && (att_server->request_buffer[0] == ATT_EXCHANGE_MTU_REQUEST)){
att_response_size = 5;
att_response_buffer[0] = ATT_ERROR_RESPONSE;
att_response_buffer[1] = ATT_EXCHANGE_MTU_REQUEST;
att_response_buffer[2] = 0;
att_response_buffer[3] = 0;
att_response_buffer[4] = ATT_ERROR_REQUEST_NOT_SUPPORTED;
} else {
att_response_size = att_handle_request(att_connection, att_server->request_buffer, att_server->request_size, att_response_buffer);
}
#ifdef ENABLE_ATT_DELAYED_RESPONSE
if ((att_response_size == ATT_READ_RESPONSE_PENDING) || (att_response_size == ATT_INTERNAL_WRITE_RESPONSE_PENDING)){
att_server_handle_response_pending(att_server, att_connection, eatt_buffer, att_response_size);
return 0;
}
#endif
// intercept "insufficient authorization" for authenticated connections to allow for user authorization
if ((att_response_size >= 4u)
&& (att_response_buffer[0] == ATT_ERROR_RESPONSE)
&& (att_response_buffer[4] == ATT_ERROR_INSUFFICIENT_AUTHORIZATION)
&& (att_connection->authenticated != 0u)){
switch (gap_authorization_state(att_connection->con_handle)){
case AUTHORIZATION_UNKNOWN:
if (eatt_buffer == NULL){
l2cap_release_packet_buffer();
}
sm_request_pairing(att_connection->con_handle);
return 0;
case AUTHORIZATION_PENDING:
if (eatt_buffer == NULL){
l2cap_release_packet_buffer();
}
return 0;
default:
break;
}
}
att_server->state = ATT_SERVER_IDLE;
if (att_response_size == 0u) {
if (eatt_buffer == NULL){
l2cap_release_packet_buffer();
}
return 0;
}
(void) att_server_send_prepared(att_server, att_connection, eatt_buffer, 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);
}
return 1;
}
#ifdef ENABLE_ATT_DELAYED_RESPONSE
uint8_t att_server_response_ready(hci_con_handle_t con_handle){
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
att_server_t * att_server = &hci_connection->att_server;
att_connection_t * att_connection = &hci_connection->att_connection;
if (att_server->state != ATT_SERVER_RESPONSE_PENDING) return ERROR_CODE_COMMAND_DISALLOWED;
att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED;
att_server_request_can_send_now(att_server, att_connection);
return ERROR_CODE_SUCCESS;
}
#endif
static void att_run_for_context(att_server_t * att_server, att_connection_t * att_connection){
switch (att_server->state){
case ATT_SERVER_REQUEST_RECEIVED:
switch (att_server->bearer_type){
case ATT_BEARER_UNENHANCED_LE:
// wait until re-encryption as central is complete
if (gap_reconnect_security_setup_active(att_connection->con_handle)) {
return;
};
break;
#if defined(ENABLE_GATT_OVER_CLASSIC) || defined (ENABLE_GATT_OVER_EATT)
#ifdef ENABLE_GATT_OVER_CLASSIC
case ATT_BEARER_UNENHANCED_CLASSIC:
/* fall through */
#endif
#ifdef ENABLE_GATT_OVER_EATT
case ATT_BEARER_ENHANCED_LE:
#endif
// ok
break;
#endif
default:
btstack_unreachable();
break;
}
// wait until pairing is complete
if (att_server->pairing_active) break;
#ifdef ENABLE_LE_SIGNED_WRITE
if (att_server->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_server->request_size < (3 + 12)) {
log_info("ATT Signed Write, request to short. Abort.");
att_server->state = ATT_SERVER_IDLE;
return;
}
if (att_server->ir_lookup_active){
return;
}
if (att_server->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 = little_endian_read_32(att_server->request_buffer, att_server->request_size-12);
uint32_t counter_db = le_device_db_remote_counter_get(att_server->ir_le_device_db_index);
log_info("ATT Signed Write, DB counter %"PRIu32", packet counter %"PRIu32, 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_remote_csrk_get(att_server->ir_le_device_db_index, csrk);
att_server->state = ATT_SERVER_W4_SIGNED_WRITE_VALIDATION;
log_info("Orig Signature: ");
log_info_hexdump( &att_server->request_buffer[att_server->request_size-8], 8);
uint16_t attribute_handle = little_endian_read_16(att_server->request_buffer, 1);
sm_cmac_signed_write_start(csrk, att_server->request_buffer[0], attribute_handle, att_server->request_size - 15, &att_server->request_buffer[3], counter_packet, att_signed_write_handle_cmac_result);
return;
}
#endif
// move on
att_server->state = ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED;
att_server_request_can_send_now(att_server, att_connection);
break;
default:
break;
}
}
static bool att_server_data_ready_for_phase(att_server_t * att_server, att_server_run_phase_t phase){
switch (phase){
case ATT_SERVER_RUN_PHASE_1_REQUESTS:
return att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED;
case ATT_SERVER_RUN_PHASE_2_INDICATIONS:
return (!btstack_linked_list_empty(&att_server->indication_requests) && (att_server->value_indication_handle == 0u));
case ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS:
return (!btstack_linked_list_empty(&att_server->notification_requests));
default:
btstack_assert(false);
return false;
}
}
static void att_server_trigger_send_for_phase(att_server_t * att_server, att_connection_t * att_connection, att_server_run_phase_t phase){
btstack_context_callback_registration_t * client;
switch (phase){
case ATT_SERVER_RUN_PHASE_1_REQUESTS:
att_server_process_validated_request(att_server, att_connection, NULL);
break;
case ATT_SERVER_RUN_PHASE_2_INDICATIONS:
client = (btstack_context_callback_registration_t*) att_server->indication_requests;
btstack_linked_list_remove(&att_server->indication_requests, (btstack_linked_item_t *) client);
client->callback(client->context);
break;
case ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS:
client = (btstack_context_callback_registration_t*) att_server->notification_requests;
btstack_linked_list_remove(&att_server->notification_requests, (btstack_linked_item_t *) client);
client->callback(client->context);
break;
default:
btstack_assert(false);
break;
}
}
static void att_server_handle_can_send_now(void){
hci_con_handle_t last_send_con_handle = HCI_CON_HANDLE_INVALID;
hci_connection_t * request_hci_connection = NULL;
bool can_send_now = true;
uint8_t phase_index;
for (phase_index = ATT_SERVER_RUN_PHASE_1_REQUESTS; phase_index <= ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS; phase_index++){
att_server_run_phase_t phase = (att_server_run_phase_t) phase_index;
hci_con_handle_t skip_connections_until = att_server_last_can_send_now;
while (true){
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);
att_server_t * att_server = &connection->att_server;
att_connection_t * att_connection = &connection->att_connection;
bool data_ready = att_server_data_ready_for_phase(att_server, phase);
// log_debug("phase %u, handle 0x%04x, skip until 0x%04x, data ready %u", phase, att_connection->con_handle, skip_connections_until, data_ready);
// skip until last sender found (which is also skipped)
if (skip_connections_until != HCI_CON_HANDLE_INVALID){
if (data_ready && (request_hci_connection == NULL)){
request_hci_connection = connection;
}
if (skip_connections_until == att_connection->con_handle){
skip_connections_until = HCI_CON_HANDLE_INVALID;
}
continue;
};
if (data_ready){
if (can_send_now){
att_server_trigger_send_for_phase(att_server, att_connection, phase);
last_send_con_handle = att_connection->con_handle;
can_send_now = att_server_can_send_packet(att_server, att_connection);
data_ready = att_server_data_ready_for_phase(att_server, phase);
if (data_ready && (request_hci_connection == NULL)){
request_hci_connection = connection;
}
} else {
request_hci_connection = connection;
break;
}
}
}
// stop skipping (handles disconnect by last send connection)
skip_connections_until = HCI_CON_HANDLE_INVALID;
// Exit loop, if we cannot send
if (!can_send_now) break;
// Exit loop, if we can send but there are also no further request
if (request_hci_connection == NULL) break;
// Finally, if we still can send and there are requests, just try again
request_hci_connection = NULL;
}
// update last send con handle for round robin
if (last_send_con_handle != HCI_CON_HANDLE_INVALID){
att_server_last_can_send_now = last_send_con_handle;
}
}
if (request_hci_connection == NULL) return;
att_server_t * att_server = &request_hci_connection->att_server;
att_connection_t * att_connection = &request_hci_connection->att_connection;
att_server_request_can_send_now(att_server, att_connection);
}
static void att_server_handle_att_pdu(att_server_t * att_server, att_connection_t * att_connection, uint8_t * packet, uint16_t size){
uint8_t opcode = packet[0u];
uint8_t method = opcode & 0x03fu;
bool invalid = method > ATT_MULTIPLE_HANDLE_VALUE_NTF;
bool command = (opcode & 0x40u) != 0u;
// ignore invalid commands
if (invalid && command){
return;
}
// handle value indication confirms
if ((opcode == ATT_HANDLE_VALUE_CONFIRMATION) && (att_server->value_indication_handle != 0u)){
btstack_run_loop_remove_timer(&att_server->value_indication_timer);
uint16_t att_handle = att_server->value_indication_handle;
att_server->value_indication_handle = 0u;
att_handle_value_indication_notify_client(0u, att_connection->con_handle, att_handle);
att_server_request_can_send_now(att_server, att_connection);
return;
}
// directly process command
// note: signed write cannot be handled directly as authentication needs to be verified
if (opcode == ATT_WRITE_COMMAND){
att_handle_request(att_connection, packet, size, NULL);
return;
}
// check size
if (size > sizeof(att_server->request_buffer)) {
log_info("drop att pdu 0x%02x as size %u > att_server->request_buffer %u", packet[0], size, (int) sizeof(att_server->request_buffer));
return;
}
#ifdef ENABLE_LE_SIGNED_WRITE
// abort signed write validation if a new request comes in (but finish previous signed write if possible)
if (att_server->state == ATT_SERVER_W4_SIGNED_WRITE_VALIDATION){
if (packet[0] == ATT_SIGNED_WRITE_COMMAND){
log_info("skip new signed write request as previous is in validation");
return;
} else {
log_info("abort signed write validation to process new request");
att_server->state = ATT_SERVER_IDLE;
}
}
#endif
// last request still in processing?
if (att_server->state != ATT_SERVER_IDLE){
log_info("skip att pdu 0x%02x as server not idle (state %u)", packet[0], att_server->state);
return;
}
// store request
att_server->state = ATT_SERVER_REQUEST_RECEIVED;
att_server->request_size = size;
(void)memcpy(att_server->request_buffer, packet, size);
att_run_for_context(att_server, att_connection);
}
static void att_server_dispatch_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
hci_connection_t * hci_connection;
att_connection_t * att_connection;
att_server_t * att_server;
#ifdef ENABLE_GATT_OVER_CLASSIC
hci_con_handle_t con_handle;
bd_addr_t address;
btstack_linked_list_iterator_t it;
#endif
switch (packet_type){
case HCI_EVENT_PACKET:
switch (packet[0]){
#ifdef ENABLE_GATT_OVER_CLASSIC
case L2CAP_EVENT_CHANNEL_OPENED:
con_handle = l2cap_event_channel_opened_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) break;
att_server = &hci_connection->att_server;
// store connection info
att_server->bearer_type = ATT_BEARER_UNENHANCED_CLASSIC;
att_server->peer_addr_type = BD_ADDR_TYPE_ACL;
l2cap_event_channel_opened_get_address(packet, att_server->peer_address);
att_connection = &hci_connection->att_connection;
att_connection->con_handle = con_handle;
// reset connection properties
att_server->state = ATT_SERVER_IDLE;
att_connection->mtu = l2cap_event_channel_opened_get_remote_mtu(packet);
att_connection->max_mtu = l2cap_max_mtu();
if (att_connection->max_mtu > ATT_REQUEST_BUFFER_SIZE){
att_connection->max_mtu = ATT_REQUEST_BUFFER_SIZE;
}
log_info("Connection opened %s, l2cap cid %04x, mtu %u", bd_addr_to_str(address), att_server->l2cap_cid, att_connection->mtu);
// update security params
att_connection->encryption_key_size = gap_encryption_key_size(con_handle);
att_connection->authenticated = gap_authenticated(con_handle);
att_connection->secure_connection = gap_secure_connection(con_handle);
log_info("encrypted key size %u, authenticated %u, secure connection %u",
att_connection->encryption_key_size, att_connection->authenticated, att_connection->secure_connection);
// notify connection opened
att_emit_connected_event(att_server, att_connection);
// restore persisten ccc if encrypted
if ( gap_security_level(con_handle) >= LEVEL_2){
att_server_persistent_ccc_restore(att_server, att_connection);
}
// TODO: what to do about le device db?
att_server->pairing_active = 0;
break;
#endif
case L2CAP_EVENT_CAN_SEND_NOW:
att_server_handle_can_send_now();
break;
case ATT_EVENT_MTU_EXCHANGE_COMPLETE:
// GATT client has negotiated the mtu for this connection
hci_connection = hci_connection_for_handle(channel);
if (!hci_connection) break;
att_connection = &hci_connection->att_connection;
att_connection->mtu = little_endian_read_16(packet, 4);
break;
default:
break;
}
break;
case ATT_DATA_PACKET:
log_debug("ATT Packet, handle 0x%04x", channel);
hci_connection = hci_connection_for_handle(channel);
if (!hci_connection) break;
att_server = &hci_connection->att_server;
att_connection = &hci_connection->att_connection;
att_server_handle_att_pdu(att_server, att_connection, packet, size);
break;
#ifdef ENABLE_GATT_OVER_CLASSIC
case L2CAP_DATA_PACKET:
hci_connections_get_iterator(&it);
while(btstack_linked_list_iterator_has_next(&it)){
hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it);
att_server = &hci_connection->att_server;
att_connection = &hci_connection->att_connection;
if (att_server->l2cap_cid == channel) {
att_server_handle_att_pdu(att_server, att_connection, packet, size);
break;
}
}
break;
#endif
default:
break;
}
}
// ---------------------
// persistent CCC writes
static uint32_t att_server_persistent_ccc_tag_for_index(uint8_t index){
return ('B' << 24u) | ('T' << 16u) | ('C' << 8u) | index;
}
static void att_server_persistent_ccc_write(hci_con_handle_t con_handle, uint16_t att_handle, uint16_t value){
// lookup att_server instance
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return;
att_server_t * att_server = &hci_connection->att_server;
int le_device_index = att_server->ir_le_device_db_index;
log_info("Store CCC value 0x%04x for handle 0x%04x of remote %s, le device id %d", value, att_handle, bd_addr_to_str(att_server->peer_address), le_device_index);
// check if bonded
if (le_device_index < 0) return;
// get btstack_tlv
const btstack_tlv_t * tlv_impl = NULL;
void * tlv_context;
btstack_tlv_get_instance(&tlv_impl, &tlv_context);
if (!tlv_impl) return;
// update ccc tag
int index;
uint32_t highest_seq_nr = 0;
uint32_t lowest_seq_nr = 0;
uint32_t tag_for_lowest_seq_nr = 0;
uint32_t tag_for_empty = 0;
persistent_ccc_entry_t entry;
for (index=0; index<NVN_NUM_GATT_SERVER_CCC; index++){
uint32_t tag = att_server_persistent_ccc_tag_for_index(index);
int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t));
// empty/invalid tag
if (len != sizeof(persistent_ccc_entry_t)){
tag_for_empty = tag;
continue;
}
// update highest seq nr
if (entry.seq_nr > highest_seq_nr){
highest_seq_nr = entry.seq_nr;
}
// find entry with lowest seq nr
if ((tag_for_lowest_seq_nr == 0u) || (entry.seq_nr < lowest_seq_nr)){
tag_for_lowest_seq_nr = tag;
lowest_seq_nr = entry.seq_nr;
}
if (entry.device_index != le_device_index) continue;
if (entry.att_handle != att_handle) continue;
// found matching entry
if (value != 0){
// update
if (entry.value == value) {
log_info("CCC Index %u: Up-to-date", index);
return;
}
entry.value = (uint8_t) value;
entry.seq_nr = highest_seq_nr + 1u;
log_info("CCC Index %u: Store", index);
int result = tlv_impl->store_tag(tlv_context, tag, (const uint8_t *) &entry, sizeof(persistent_ccc_entry_t));
if (result != 0){
log_error("Store tag index %u failed", index);
}
} else {
// delete
log_info("CCC Index %u: Delete", index);
tlv_impl->delete_tag(tlv_context, tag);
}
return;
}
static void att_server_persistent_ccc_clear(att_server_t * att_server){
int le_device_index = att_server->ir_le_device_db_index;
log_info("Clear CCC values of remote %s, le device id %d", bd_addr_to_str(att_server->peer_address), le_device_index);
// check if bonded
if (le_device_index < 0) return;
// get btstack_tlv
const btstack_tlv_t * tlv_impl = NULL;
void * tlv_context;
btstack_tlv_get_instance(&tlv_impl, &tlv_context);
if (!tlv_impl) return;
// get all ccc tag
int index;
persistent_ccc_entry_t entry;
for (index=0;index<NVN_NUM_GATT_SERVER_CCC;index++){
uint32_t tag = att_server_persistent_ccc_tag_for_index(index);
int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t));
if (len != sizeof(persistent_ccc_entry_t)) continue;
if (entry.device_index != le_device_index) continue;
// delete entry
log_info("CCC Index %u: Delete", index);
tlv_impl->delete_tag(tlv_context, tag);
}
static void att_server_persistent_ccc_restore(att_server_t * att_server, att_connection_t * att_connection){
int le_device_index = att_server->ir_le_device_db_index;
log_info("Restore CCC values of remote %s, le device id %d", bd_addr_to_str(att_server->peer_address), le_device_index);
// check if bonded
if (le_device_index < 0) return;
// get btstack_tlv
const btstack_tlv_t * tlv_impl = NULL;
void * tlv_context;
btstack_tlv_get_instance(&tlv_impl, &tlv_context);
if (!tlv_impl) return;
// get all ccc tag
int index;
persistent_ccc_entry_t entry;
for (index=0;index<NVN_NUM_GATT_SERVER_CCC;index++){
uint32_t tag = att_server_persistent_ccc_tag_for_index(index);
int len = tlv_impl->get_tag(tlv_context, tag, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t));
if (len != sizeof(persistent_ccc_entry_t)) continue;
if (entry.device_index != le_device_index) continue;
// simulate write callback
uint16_t attribute_handle = entry.att_handle;
uint8_t value[2];
little_endian_store_16(value, 0, entry.value);
att_write_callback_t callback = att_server_write_callback_for_handle(attribute_handle);
if (!callback) continue;
log_info("CCC Index %u: Set Attribute handle 0x%04x to value 0x%04x", index, attribute_handle, entry.value );
(*callback)(att_connection->con_handle, attribute_handle, ATT_TRANSACTION_MODE_NONE, 0, value, sizeof(value));
}
// persistent CCC writes
// ---------------------
// gatt service management
static att_service_handler_t * att_service_handler_for_handle(uint16_t handle){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &service_handlers);
while (btstack_linked_list_iterator_has_next(&it)){
att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it);
if (handler->start_handle > handle) continue;
if (handler->end_handle < handle) continue;
return handler;
}
return NULL;
}
static att_write_callback_t att_server_write_callback_for_handle(uint16_t handle){
att_service_handler_t * handler = att_service_handler_for_handle(handle);
if (handler != NULL) return handler->write_callback;
return att_server_client_write_callback;
}
static btstack_packet_handler_t att_server_packet_handler_for_handle(uint16_t handle){
att_service_handler_t * handler = att_service_handler_for_handle(handle);
if (handler != NULL) return handler->packet_handler;
return att_client_packet_handler;
}
static void att_notify_write_callbacks(hci_con_handle_t con_handle, uint16_t transaction_mode){
// notify all callbacks
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &service_handlers);
while (btstack_linked_list_iterator_has_next(&it)){
att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it);
if (!handler->write_callback) continue;
(*handler->write_callback)(con_handle, 0, transaction_mode, 0, NULL, 0);
}
if (!att_server_client_write_callback) return;
(*att_server_client_write_callback)(con_handle, 0, transaction_mode, 0, NULL, 0);
}
// returns first reported error or 0
static uint8_t att_validate_prepared_write(hci_con_handle_t con_handle){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &service_handlers);
while (btstack_linked_list_iterator_has_next(&it)){
att_service_handler_t * handler = (att_service_handler_t*) btstack_linked_list_iterator_next(&it);
if (!handler->write_callback) continue;
uint8_t error_code = (*handler->write_callback)(con_handle, 0, ATT_TRANSACTION_MODE_VALIDATE, 0, NULL, 0);
if (error_code != 0u) return error_code;
}
if (!att_server_client_write_callback) return 0;
return (*att_server_client_write_callback)(con_handle, 0, ATT_TRANSACTION_MODE_VALIDATE, 0, NULL, 0);
}
static uint16_t att_server_read_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
att_service_handler_t * service = att_service_handler_for_handle(attribute_handle);
att_read_callback_t read_callback = (service != NULL) ? service->read_callback : att_server_client_read_callback;
uint16_t result = 0;
if (read_callback != NULL){
result = (*read_callback)(con_handle, attribute_handle, offset, buffer, buffer_size);
#ifdef ENABLE_ATT_DELAYED_RESPONSE
if (result == ATT_READ_RESPONSE_PENDING){
if (service == NULL){
att_server_flags |= ATT_SERVICE_FLAGS_DELAYED_RESPONSE;
} else {
service->flags |= ATT_SERVICE_FLAGS_DELAYED_RESPONSE;
}
}
#endif
}
return result;
}
static int att_server_write_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t transaction_mode, uint16_t offset, uint8_t *buffer, uint16_t buffer_size){
switch (transaction_mode){
case ATT_TRANSACTION_MODE_VALIDATE:
return att_validate_prepared_write(con_handle);
case ATT_TRANSACTION_MODE_EXECUTE:
case ATT_TRANSACTION_MODE_CANCEL:
att_notify_write_callbacks(con_handle, transaction_mode);
return 0;
default:
break;
}
// track CCC writes
if (att_is_persistent_ccc(attribute_handle) && (offset == 0u) && (buffer_size == 2u)){
att_server_persistent_ccc_write(con_handle, attribute_handle, little_endian_read_16(buffer, 0));
}
att_write_callback_t callback = att_server_write_callback_for_handle(attribute_handle);
if (!callback) return 0;
return (*callback)(con_handle, attribute_handle, transaction_mode, offset, buffer, buffer_size);
}
/**
* @brief register read/write callbacks for specific handle range
* @param att_service_handler_t
*/
void att_server_register_service_handler(att_service_handler_t * handler){
bool att_server_registered = false;
if (att_service_handler_for_handle(handler->start_handle) != NULL){
att_server_registered = true;
}
if (att_service_handler_for_handle(handler->end_handle) != NULL){
att_server_registered = true;
}
if (att_server_registered){
log_error("handler for range 0x%04x-0x%04x already registered", handler->start_handle, handler->end_handle);
return;
}
handler->flags = 0;
btstack_linked_list_add(&service_handlers, (btstack_linked_item_t*) handler);
}
void att_server_init(uint8_t const * db, att_read_callback_t read_callback, att_write_callback_t write_callback){
// store callbacks
att_server_client_read_callback = read_callback;
att_server_client_write_callback = write_callback;
// register for HCI Events
hci_event_callback_registration.callback = &att_server_event_packet_handler;
hci_add_event_handler(&hci_event_callback_registration);
// register for SM events
sm_event_callback_registration.callback = &att_server_event_packet_handler;
sm_add_event_handler(&sm_event_callback_registration);
// and L2CAP ATT Server PDUs
att_dispatch_register_server(att_server_dispatch_packet_handler);
#ifdef ENABLE_GATT_OVER_CLASSIC
// setup l2cap service
att_dispatch_classic_register_service();
#endif
att_set_db(db);
att_set_read_callback(att_server_read_callback);
att_set_write_callback(att_server_write_callback);
}
void att_server_register_packet_handler(btstack_packet_handler_t handler){
att_client_packet_handler = handler;
}
// to be deprecated
int att_server_can_send_packet_now(hci_con_handle_t con_handle){
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return 0;
att_server_t * att_server = &hci_connection->att_server;
att_connection_t * att_connection = &hci_connection->att_connection;
return att_server_can_send_packet(att_server, att_connection);
}
uint8_t att_server_register_can_send_now_callback(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){
return att_server_request_to_send_notification(callback_registration, con_handle);
}
void att_server_request_can_send_now_event(hci_con_handle_t con_handle){
att_client_waiting_for_can_send_registration.callback = &att_emit_can_send_now_event;
att_server_request_to_send_notification(&att_client_waiting_for_can_send_registration, con_handle);
}
// end of deprecated
uint8_t att_server_request_to_send_notification(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
att_server_t * att_server = &hci_connection->att_server;
att_connection_t * att_connection = &hci_connection->att_connection;
bool added = btstack_linked_list_add_tail(&att_server->notification_requests, (btstack_linked_item_t*) callback_registration);
att_server_request_can_send_now(att_server, att_connection);
if (added){
return ERROR_CODE_SUCCESS;
} else {
return ERROR_CODE_COMMAND_DISALLOWED;
}
}
uint8_t att_server_request_to_send_indication(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
att_server_t * att_server = &hci_connection->att_server;
att_connection_t * att_connection = &hci_connection->att_connection;
bool added = btstack_linked_list_add_tail(&att_server->indication_requests, (btstack_linked_item_t*) callback_registration);
att_server_request_can_send_now(att_server, att_connection);
if (added){
return ERROR_CODE_SUCCESS;
} else {
return ERROR_CODE_COMMAND_DISALLOWED;
}
}
static uint8_t att_server_prepare_server_message(hci_con_handle_t con_handle, att_server_t ** out_att_server, att_connection_t ** out_att_connection, uint8_t ** out_packet_buffer){
att_server_t * att_server = NULL;
att_connection_t * att_connection = NULL;
uint8_t * packet_buffer = NULL;
// prefer enhanced bearer
#ifdef ENABLE_GATT_OVER_EATT
att_server_eatt_bearer_t * eatt_bearer = att_server_eatt_bearer_for_con_handle(con_handle);
if (eatt_bearer != NULL){
att_server = &eatt_bearer->att_server;
att_connection = &eatt_bearer->att_connection;
packet_buffer = eatt_bearer->send_buffer;
} else
#endif
{
hci_connection_t *hci_connection = hci_connection_for_handle(con_handle);
if (hci_connection != NULL) {
att_server = &hci_connection->att_server;
att_connection = &hci_connection->att_connection;
}
}
if (att_server == NULL) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
if (!att_server_can_send_packet(att_server, att_connection)) return BTSTACK_ACL_BUFFERS_FULL;
if (packet_buffer == NULL){
l2cap_reserve_packet_buffer();
packet_buffer = l2cap_get_outgoing_buffer();
}
*out_att_connection = att_connection;
*out_att_server = att_server;
*out_packet_buffer = packet_buffer;
return ERROR_CODE_SUCCESS;
}
uint8_t att_server_notify(hci_con_handle_t con_handle, uint16_t attribute_handle, const uint8_t *value, uint16_t value_len){
att_server_t * att_server = NULL;
att_connection_t * att_connection = NULL;
uint8_t * packet_buffer = NULL;
uint8_t status = att_server_prepare_server_message(con_handle, &att_server, &att_connection, &packet_buffer);
if (status != ERROR_CODE_SUCCESS){
return status;
}
uint16_t size = att_prepare_handle_value_notification(att_connection, attribute_handle, value, value_len, packet_buffer);
return att_server_send_prepared(att_server, att_connection, NULL, size);
}
/**
* @brief notify client about multiple attribute value changes
* @param con_handle
* @param num_attributes
* @param attribute_handles[]
* @param values_data[]
* @param values_len[]
* @return 0 if ok, error otherwise
*/
uint8_t att_server_multiple_notify(hci_con_handle_t con_handle, uint8_t num_attributes,
const uint16_t * attribute_handles, const uint8_t ** values_data, const uint16_t * values_len){
att_server_t * att_server = NULL;
att_connection_t * att_connection = NULL;
uint8_t * packet_buffer = NULL;
uint8_t status = att_server_prepare_server_message(con_handle, &att_server, &att_connection, &packet_buffer);
if (status != ERROR_CODE_SUCCESS){
return status;
}
uint16_t size = att_prepare_handle_value_multiple_notification(att_connection, num_attributes, attribute_handles, values_data, values_len, packet_buffer);
return att_server_send_prepared(att_server, att_connection, packet_buffer, size);
}
uint8_t att_server_indicate(hci_con_handle_t con_handle, uint16_t attribute_handle, const uint8_t *value, uint16_t value_len){
att_server_t * att_server = NULL;
att_connection_t * att_connection = NULL;
uint8_t * packet_buffer = NULL;
uint8_t status = att_server_prepare_server_message(con_handle, &att_server, &att_connection, &packet_buffer);
if (status != ERROR_CODE_SUCCESS){
return status;
}
if (att_server->value_indication_handle != 0u) {
// free reserved packet buffer
if (att_server->bearer_type == ATT_BEARER_ENHANCED_LE){
l2cap_release_packet_buffer();
}
return ATT_HANDLE_VALUE_INDICATION_IN_PROGRESS;
}
// 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);
uint16_t size = att_prepare_handle_value_indication(att_connection, attribute_handle, value, value_len, packet_buffer);
return att_server_send_prepared(att_server, att_connection, NULL, size);
}
uint16_t att_server_get_mtu(hci_con_handle_t con_handle){
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return 0;
att_connection_t * att_connection = &hci_connection->att_connection;
return att_connection->mtu;
}
void att_server_deinit(void){
att_server_client_read_callback = NULL;
att_server_client_write_callback = NULL;
att_client_packet_handler = NULL;
service_handlers = NULL;
att_server_flags = 0;
}
#ifdef ENABLE_GATT_OVER_EATT
#define MAX_NR_EATT_CHANNELS 5
static uint16_t att_server_eatt_receive_buffer_size;
static uint16_t att_server_eatt_send_buffer_size;
static att_server_eatt_bearer_t * att_server_eatt_bearer_for_cid(uint16_t cid){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &att_server_eatt_bearer_active);
while(btstack_linked_list_iterator_has_next(&it)){
att_server_eatt_bearer_t * eatt_bearer = (att_server_eatt_bearer_t *) btstack_linked_list_iterator_next(&it);
if (eatt_bearer->att_server.l2cap_cid == cid) {
return eatt_bearer;
}
}
return NULL;
}
static att_server_eatt_bearer_t * att_server_eatt_bearer_for_con_handle(hci_con_handle_t con_handle){
btstack_linked_list_iterator_t it;
btstack_linked_list_iterator_init(&it, &att_server_eatt_bearer_active);
while(btstack_linked_list_iterator_has_next(&it)){
att_server_eatt_bearer_t * eatt_bearer = (att_server_eatt_bearer_t *) btstack_linked_list_iterator_next(&it);
if (eatt_bearer->att_connection.con_handle == con_handle) {
return eatt_bearer;
}
}
return NULL;
}
static void att_server_eatt_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
uint16_t cid;
uint8_t status;
uint16_t remote_mtu;
uint8_t i;
uint8_t num_requested_bearers;
uint8_t num_accepted_bearers;
uint16_t initial_credits = L2CAP_LE_AUTOMATIC_CREDITS;
uint8_t * receive_buffers[MAX_NR_EATT_CHANNELS];
uint16_t cids[MAX_NR_EATT_CHANNELS];
att_server_eatt_bearer_t * eatt_bearers[MAX_NR_EATT_CHANNELS];
att_server_eatt_bearer_t * eatt_bearer;
att_server_t * att_server;
att_connection_t * att_connection;
hci_con_handle_t con_handle;
hci_connection_t * hci_connection;
switch (packet_type) {
case L2CAP_DATA_PACKET:
eatt_bearer = att_server_eatt_bearer_for_cid(channel);
btstack_assert(eatt_bearer != NULL);
att_server = &eatt_bearer->att_server;
att_connection = &eatt_bearer->att_connection;
att_server_handle_att_pdu(att_server, att_connection, packet, size);
break;
case HCI_EVENT_PACKET:
switch (packet[0]) {
case L2CAP_EVENT_CAN_SEND_NOW:
cid = l2cap_event_packet_sent_get_local_cid(packet);
eatt_bearer = att_server_eatt_bearer_for_cid(cid);
btstack_assert(eatt_bearer != NULL);
att_server = &eatt_bearer->att_server;
att_connection = &eatt_bearer->att_connection;
// only used for EATT request responses
btstack_assert(att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED);
att_server_process_validated_request(att_server, att_connection, eatt_bearer->send_buffer);
break;
case L2CAP_EVENT_PACKET_SENT:
cid = l2cap_event_packet_sent_get_local_cid(packet);
eatt_bearer = att_server_eatt_bearer_for_cid(cid);
btstack_assert(eatt_bearer != NULL);
att_server = &eatt_bearer->att_server;
att_connection = &eatt_bearer->att_connection;
att_server_handle_att_pdu(att_server, att_connection, packet, size);
break;
case L2CAP_EVENT_ECBM_INCOMING_CONNECTION:
cid = l2cap_event_ecbm_incoming_connection_get_local_cid(packet);
// reject if outgoing l2cap connection active, L2CAP/TIM/BV-01-C
con_handle = l2cap_event_ecbm_incoming_connection_get_handle(packet);
hci_connection = hci_connection_for_handle(con_handle);
btstack_assert(hci_connection != NULL);
if (hci_connection->att_server.eatt_outgoing_active) {
hci_connection->att_server.incoming_connection_request = true;
l2cap_ecbm_decline_channels(cid, L2CAP_ECBM_CONNECTION_RESULT_SOME_REFUSED_INSUFFICIENT_RESOURCES_AVAILABLE );
log_info("Decline incoming connection from %s", bd_addr_to_str(hci_connection->address));
} else {
num_requested_bearers = l2cap_event_ecbm_incoming_connection_get_num_channels(packet);
for (i = 0; i < num_requested_bearers; i++){
eatt_bearers[i] = (att_server_eatt_bearer_t *) btstack_linked_list_pop(&att_server_eatt_bearer_pool);
if (eatt_bearers[i] == NULL) {
break;
}
eatt_bearers[i]->att_connection.con_handle = l2cap_event_ecbm_incoming_connection_get_handle(packet);
eatt_bearers[i]->att_server.bearer_type = ATT_BEARER_ENHANCED_LE;
receive_buffers[i] = eatt_bearers[i]->receive_buffer;
btstack_linked_list_add(&att_server_eatt_bearer_active, (btstack_linked_item_t *) eatt_bearers[i]);
}
num_accepted_bearers = i;
status = l2cap_ecbm_accept_channels(cid, num_accepted_bearers, initial_credits, att_server_eatt_receive_buffer_size, receive_buffers, cids);
btstack_assert(status == ERROR_CODE_SUCCESS);
log_info("requested %u, accepted %u", num_requested_bearers, num_accepted_bearers);
for (i=0;i<num_accepted_bearers;i++){
log_info("eatt l2cap cid: 0x%04x", cids[i]);
eatt_bearers[i]->att_server.l2cap_cid = cids[i];
}
break;
case L2CAP_EVENT_ECBM_CHANNEL_OPENED:
cid = l2cap_event_ecbm_channel_opened_get_local_cid(packet);
status = l2cap_event_ecbm_channel_opened_get_status(packet);
remote_mtu = l2cap_event_ecbm_channel_opened_get_remote_mtu(packet);
eatt_bearer = att_server_eatt_bearer_for_cid(cid);
btstack_assert(eatt_bearer != NULL);
eatt_bearer->att_connection.mtu_exchanged = true;
eatt_bearer->att_connection.mtu = remote_mtu;
eatt_bearer->att_connection.max_mtu = remote_mtu;
log_info("L2CAP_EVENT_ECBM_CHANNEL_OPENED - cid 0x%04x mtu %u, status 0x%02x", cid, remote_mtu, status);
break;
case L2CAP_EVENT_ECBM_RECONFIGURED:
break;
case L2CAP_EVENT_CHANNEL_CLOSED:
eatt_bearer = att_server_eatt_bearer_for_cid(l2cap_event_channel_closed_get_local_cid(packet));
btstack_assert(eatt_bearers != NULL);
// TODO: finalize - abort queued writes
btstack_linked_list_remove(&att_server_eatt_bearer_active, (btstack_linked_item_t *) eatt_bearer);
btstack_linked_list_add(&att_server_eatt_bearer_pool, (btstack_linked_item_t *) eatt_bearer);
break;
default:
break;
}
break;
default:
btstack_unreachable();
break;
}
}
// create eatt bearers
uint8_t att_server_eatt_init(uint8_t num_eatt_bearers, uint8_t * storage_buffer, uint16_t storage_size){
uint16_t size_for_structs = num_eatt_bearers * sizeof(att_server_eatt_bearer_t);
if (storage_size < size_for_structs) {
return ERROR_CODE_MEMORY_CAPACITY_EXCEEDED;
}
// TODO: The minimum ATT_MTU for an Enhanced ATT bearer is 64 octets.
memset(storage_buffer, 0, storage_size);
uint16_t buffer_size_per_bearer = ((storage_size - size_for_structs) / num_eatt_bearers);
att_server_eatt_receive_buffer_size = buffer_size_per_bearer / 2;
att_server_eatt_send_buffer_size = buffer_size_per_bearer / 2;
uint8_t * bearer_buffer = &storage_buffer[size_for_structs];
uint8_t i;
att_server_eatt_bearer_t * eatt_bearer = (att_server_eatt_bearer_t *) storage_buffer;
log_info("%u EATT bearers with receive buffer size %u",
num_eatt_bearers, att_server_eatt_receive_buffer_size);
for (i=0;i<num_eatt_bearers;i++){
eatt_bearer->att_connection.con_handle = HCI_CON_HANDLE_INVALID;
eatt_bearer->receive_buffer = bearer_buffer;
bearer_buffer += att_server_eatt_receive_buffer_size;
eatt_bearer->send_buffer = bearer_buffer;
bearer_buffer += att_server_eatt_send_buffer_size;
btstack_linked_list_add(&att_server_eatt_bearer_pool, (btstack_linked_item_t *) eatt_bearer);
eatt_bearer++;
}
#endif
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