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btstack/src/ble/att_server.c
Jakob Krantz b12646c53b att_dispatch: Propogate MTU update to both att_server and gatt_client. 
According to the BT 5.0 spec. A MTU negotiation shall only be required in one
direction. I.e. We must propogate the negotiated MTU between gatt_client
and att_server.
2018-01-30 19:12:33 +01:00

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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 MATTHIAS
* RINGWALD 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include "btstack_config.h"
#include "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"
#ifndef NVN_NUM_GATT_SERVER_CCC
#define NVN_NUM_GATT_SERVER_CCC 20
#endif
static void att_run_for_context(att_server_t * att_server);
static att_write_callback_t att_server_write_callback_for_handle(uint16_t handle);
static void att_server_persistent_ccc_restore(att_server_t * att_server);
static void att_server_persistent_ccc_clear(att_server_t * att_server);
//
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 = NULL;
static btstack_linked_list_t can_send_now_clients;
static btstack_linked_list_t service_handlers;
static uint8_t att_client_waiting_for_can_send;
static att_read_callback_t att_server_client_read_callback;
static att_write_callback_t att_server_client_write_callback;
// track CCC 1-entry cache
// static att_server_t * att_persistent_ccc_server;
// static hci_con_handle_t att_persistent_ccc_con_handle;
static att_server_t * att_server_for_handle(hci_con_handle_t con_handle){
hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
if (!hci_connection) return NULL;
return &hci_connection->att_server;
}
#ifdef ENABLE_LE_SIGNED_WRITE
static att_server_t * att_server_for_state(att_server_state_t state){
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;
if (att_server->state == state) return att_server;
}
return NULL;
}
#endif
static void att_handle_value_indication_notify_client(uint8_t status, uint16_t client_handle, uint16_t attribute_handle){
if (!att_client_packet_handler) return;
uint8_t event[7];
int pos = 0;
event[pos++] = ATT_EVENT_HANDLE_VALUE_INDICATION_COMPLETE;
event[pos++] = sizeof(event) - 2;
event[pos++] = status;
little_endian_store_16(event, pos, client_handle);
pos += 2;
little_endian_store_16(event, pos, attribute_handle);
(*att_client_packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event));
}
static void att_emit_mtu_event(hci_con_handle_t con_handle, uint16_t mtu){
if (!att_client_packet_handler) return;
uint8_t event[6];
int pos = 0;
event[pos++] = ATT_EVENT_MTU_EXCHANGE_COMPLETE;
event[pos++] = sizeof(event) - 2;
little_endian_store_16(event, pos, con_handle);
pos += 2;
little_endian_store_16(event, pos, mtu);
att_dispatch_server_mtu_exchanged(con_handle, mtu);
(*att_client_packet_handler)(HCI_EVENT_PACKET, 0, &event[0], sizeof(event));
}
static void att_emit_can_send_now_event(void){
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_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;
att_server_t * att_server = att_server_for_handle(con_handle);
if (!att_server) return;
uint16_t att_handle = att_server->value_indication_handle;
att_handle_value_indication_notify_client(ATT_HANDLE_VALUE_INDICATION_TIMEOUT, att_server->connection.con_handle, att_handle);
}
static void att_device_identified(att_server_t * att_server, uint8_t index){
att_server->ir_lookup_active = 0;
att_server->ir_le_device_db_index = index;
log_info("Remote device with conn 0%04x registered with index id %u", (int) att_server->connection.con_handle, att_server->ir_le_device_db_index);
att_run_for_context(att_server);
}
static void att_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;
hci_con_handle_t con_handle;
switch (packet_type) {
case HCI_EVENT_PACKET:
switch (hci_event_packet_get_type(packet)) {
case HCI_EVENT_LE_META:
switch (packet[2]) {
case HCI_SUBEVENT_LE_CONNECTION_COMPLETE:
con_handle = little_endian_read_16(packet, 4);
att_server = att_server_for_handle(con_handle);
if (!att_server) break;
// store connection info
att_server->peer_addr_type = packet[7];
reverse_bd_addr(&packet[8], att_server->peer_address);
att_server->connection.con_handle = con_handle;
// reset connection properties
att_server->state = ATT_SERVER_IDLE;
att_server->connection.mtu = ATT_DEFAULT_MTU;
att_server->connection.max_mtu = l2cap_max_le_mtu();
if (att_server->connection.max_mtu > ATT_REQUEST_BUFFER_SIZE){
att_server->connection.max_mtu = ATT_REQUEST_BUFFER_SIZE;
}
att_server->connection.encryption_key_size = 0;
att_server->connection.authenticated = 0;
att_server->connection.authorized = 0;
// 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->pairing_active = 0;
break;
default:
break;
}
break;
case HCI_EVENT_ENCRYPTION_CHANGE:
case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE:
// check handle
con_handle = little_endian_read_16(packet, 3);
att_server = att_server_for_handle(con_handle);
if (!att_server) break;
att_server->connection.encryption_key_size = gap_encryption_key_size(con_handle);
att_server->connection.authenticated = gap_authenticated(con_handle);
if (hci_event_packet_get_type(packet) == HCI_EVENT_ENCRYPTION_CHANGE){
// restore CCC values when encrypted
if (hci_event_encryption_change_get_encryption_enabled(packet)){
att_server_persistent_ccc_restore(att_server);
}
}
break;
case HCI_EVENT_DISCONNECTION_COMPLETE:
// check handle
con_handle = hci_event_disconnection_complete_get_connection_handle(packet);
att_server = att_server_for_handle(con_handle);
if (!att_server) break;
att_clear_transaction_queue(&att_server->connection);
att_server->connection.con_handle = 0;
att_server->value_indication_handle = 0; // reset error state
att_server->pairing_active = 0;
att_server->state = ATT_SERVER_IDLE;
break;
// Identity Resolving
case SM_EVENT_IDENTITY_RESOLVING_STARTED:
con_handle = sm_event_identity_resolving_started_get_handle(packet);
att_server = att_server_for_handle(con_handle);
if (!att_server) break;
log_info("SM_EVENT_IDENTITY_RESOLVING_STARTED");
att_server->ir_lookup_active = 1;
break;
case SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED:
con_handle = sm_event_identity_created_get_handle(packet);
att_server = att_server_for_handle(con_handle);
if (!att_server) return;
att_device_identified(att_server, sm_event_identity_resolving_succeeded_get_index(packet));
break;
case SM_EVENT_IDENTITY_RESOLVING_FAILED:
con_handle = sm_event_identity_resolving_failed_get_handle(packet);
att_server = att_server_for_handle(con_handle);
if (!att_server) break;
log_info("SM_EVENT_IDENTITY_RESOLVING_FAILED");
att_server->ir_lookup_active = 0;
att_server->ir_le_device_db_index = -1;
att_run_for_context(att_server);
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);
att_server = att_server_for_handle(con_handle);
if (!att_server) break;
att_server->pairing_active = 1;
log_info("SM Pairing started");
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;
// Pairing completed
case SM_EVENT_IDENTITY_CREATED:
con_handle = sm_event_identity_created_get_handle(packet);
att_server = att_server_for_handle(con_handle);
if (!att_server) return;
att_server->pairing_active = 0;
att_device_identified(att_server, sm_event_identity_created_get_index(packet));
break;
// Authorization
case SM_EVENT_AUTHORIZATION_RESULT: {
con_handle = sm_event_authorization_result_get_handle(packet);
att_server = att_server_for_handle(con_handle);
if (!att_server) break;
att_server->connection.authorized = sm_event_authorization_result_get_authorization_result(packet);
att_dispatch_server_request_can_send_now_event(con_handle);
break;
}
default:
break;
}
break;
default:
break;
}
}
#ifdef ENABLE_LE_SIGNED_WRITE
static void att_signed_write_handle_cmac_result(uint8_t hash[8]){
att_server_t * att_server = att_server_for_state(ATT_SERVER_W4_SIGNED_WRITE_VALIDATION);
if (!att_server) 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)){
log_info("ATT Signed Write, invalid signature");
att_server->state = ATT_SERVER_IDLE;
return;
}
log_info("ATT Signed Write, valid signature");
// 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_dispatch_server_request_can_send_now_event(att_server->connection.con_handle);
}
#endif
// 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);
// 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;
}
static void att_run_for_context(att_server_t * att_server){
switch (att_server->state){
case ATT_SERVER_REQUEST_RECEIVED:
// 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_dispatch_server_request_can_send_now_event(att_server->connection.con_handle);
break;
default:
break;
}
}
static void att_server_handle_can_send_now(void){
// NOTE: we get l2cap fixed channel instead of con_handle
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;
if (att_server->state == ATT_SERVER_REQUEST_RECEIVED_AND_VALIDATED){
int sent = att_server_process_validated_request(att_server);
if (sent && (att_client_waiting_for_can_send || !btstack_linked_list_empty(&can_send_now_clients))){
att_dispatch_server_request_can_send_now_event(att_server->connection.con_handle);
return;
}
}
}
while (!btstack_linked_list_empty(&can_send_now_clients)){
// handle first client
btstack_context_callback_registration_t * client = (btstack_context_callback_registration_t*) can_send_now_clients;
hci_con_handle_t con_handle = (uintptr_t) client->context;
btstack_linked_list_remove(&can_send_now_clients, (btstack_linked_item_t *) client);
client->callback(client->context);
// request again if needed
if (!att_dispatch_server_can_send_now(con_handle)){
if (!btstack_linked_list_empty(&can_send_now_clients) || att_client_waiting_for_can_send){
att_dispatch_server_request_can_send_now_event(con_handle);
}
return;
}
}
if (att_client_waiting_for_can_send){
att_client_waiting_for_can_send = 0;
att_emit_can_send_now_event();
}
}
static void att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
att_server_t * att_server;
switch (packet_type){
case HCI_EVENT_PACKET:
if (packet[0] != L2CAP_EVENT_CAN_SEND_NOW) break;
att_server_handle_can_send_now();
break;
case ATT_DATA_PACKET:
log_info("ATT Packet, handle 0x%04x", handle);
att_server = att_server_for_handle(handle);
if (!att_server) break;
// Gatt client have negotiated the mtu for this connection
if (packet[0] == ATT_EVENT_MTU_EXCHANGE_COMPLETE){
att_server->connection.mtu = little_endian_read_16(packet, 4);
}
// handle value indication confirms
if (packet[0] == ATT_HANDLE_VALUE_CONFIRMATION && att_server->value_indication_handle){
btstack_run_loop_remove_timer(&att_server->value_indication_timer);
uint16_t att_handle = att_server->value_indication_handle;
att_server->value_indication_handle = 0;
att_handle_value_indication_notify_client(0, att_server->connection.con_handle, att_handle);
return;
}
// directly process command
// note: signed write cannot be handled directly as authentication needs to be verified
if (packet[0] == ATT_WRITE_COMMAND){
att_handle_request(&att_server->connection, packet, size, 0);
return;
}
// check size
if (size > sizeof(att_server->request_buffer)) {
log_info("att_packet_handler: dropping att pdu 0x%02x as size %u > att_server->request_buffer %u", packet[0], size, (int) sizeof(att_server->request_buffer));
return;
}
// last request still in processing?
if (att_server->state != ATT_SERVER_IDLE){
log_info("att_packet_handler: skipping 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;
memcpy(att_server->request_buffer, packet, size);
att_run_for_context(att_server);
break;
}
}
// ---------------------
// persistent CCC writes
static uint32_t att_server_persistent_ccc_tag_for_index(uint8_t index){
return 'B' << 24 | 'T' << 16 | 'C' << 8 | 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
att_server_t * att_server = att_server_for_handle(con_handle);
if (!att_server) return;
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 == 0) || (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){
// update
if (entry.value == value) {
log_info("CCC Index %u: Up-to-date", index);
return;
}
entry.value = value;
entry.seq_nr = highest_seq_nr + 1;
log_info("CCC Index %u: Store", index);
tlv_impl->store_tag(tlv_context, tag, (const uint8_t *) &entry, sizeof(persistent_ccc_entry_t));
} else {
// delete
log_info("CCC Index %u: Delete", index);
tlv_impl->delete_tag(tlv_context, tag);
}
return;
}
log_info("tag_for_empy %x, tag_for_lowest_seq_nr %x", tag_for_empty, tag_for_lowest_seq_nr);
if (value == 0){
// done
return;
}
uint32_t tag_to_use = 0;
if (tag_for_empty){
tag_to_use = tag_for_empty;
} else if (tag_for_lowest_seq_nr){
tag_to_use = tag_for_lowest_seq_nr;
} else {
// should not happen
return;
}
// store ccc tag
entry.seq_nr = highest_seq_nr + 1;
entry.device_index = le_device_index;
entry.att_handle = att_handle;
entry.value = value;
tlv_impl->store_tag(tlv_context, tag_to_use, (uint8_t *) &entry, sizeof(persistent_ccc_entry_t));
}
static void att_server_persistent_ccc_clear(att_server_t * att_server){
if (!att_server) return;
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){
if (!att_server) return;
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);
// 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_server->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_read_callback_t att_server_read_callback_for_handle(uint16_t handle){
att_service_handler_t * handler = att_service_handler_for_handle(handle);
if (handler) return handler->read_callback;
return att_server_client_read_callback;
}
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) return handler->write_callback;
return att_server_client_write_callback;
}
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) 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_read_callback_t callback = att_server_read_callback_for_handle(attribute_handle);
if (!callback) return 0;
return (*callback)(con_handle, attribute_handle, offset, buffer, buffer_size);
}
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 == 0 && buffer_size == 2){
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){
if (att_service_handler_for_handle(handler->start_handle) ||
att_service_handler_for_handle(handler->end_handle)){
log_error("handler for range 0x%04x-0x%04x already registered", handler->start_handle, handler->end_handle);
return;
}
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_event_packet_handler;
hci_add_event_handler(&hci_event_callback_registration);
// register for SM events
sm_event_callback_registration.callback = &att_event_packet_handler;
sm_add_event_handler(&sm_event_callback_registration);
// and L2CAP ATT Server PDUs
att_dispatch_register_server(att_packet_handler);
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;
}
int att_server_can_send_packet_now(hci_con_handle_t con_handle){
return att_dispatch_server_can_send_now(con_handle);
}
void att_server_request_can_send_now_event(hci_con_handle_t con_handle){
log_debug("att_server_request_can_send_now_event 0x%04x", con_handle);
att_client_waiting_for_can_send = 1;
att_dispatch_server_request_can_send_now_event(con_handle);
}
void att_server_register_can_send_now_callback(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){
// check if can send already
if (att_dispatch_server_can_send_now(con_handle)){
callback_registration->callback(callback_registration->context);
return;
}
callback_registration->context = (void*)(uintptr_t) con_handle;
btstack_linked_list_add_tail(&can_send_now_clients, (btstack_linked_item_t*) callback_registration);
att_dispatch_server_request_can_send_now_event(con_handle);
}
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);
}
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;
}
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