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hid_host: use state machine to parse HID Descriptor list with minimal attribute buffer

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This commit is contained in:
Matthias Ringwald 2023-10-15 15:53:13 +02:00
parent 483beab434
commit 1744e196a4
2 changed files with 139 additions and 27 deletions
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1
CHANGELOG.md
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@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
- HFP AG: fix setup of audio connection in service level established event
- HFP AG: fix BCM WBS setup
- HID Device: set Report Mode as default
- HID Host: support large HID Descriptors
- AVDTP: limit L2CAP MTU to largest BR/EDR packet, fixes A2DP Sink role for some Samsung TV
- AVRCP: reject incoming second l2cap connection
- AVRCP: generate command for avrcp_controller_get_element_attributes dynamically

165
src/classic/hid_host.c
View File

@ -388,7 +388,137 @@ static void hid_host_finalize_connection(hid_host_connection_t * connection){
btstack_linked_list_remove(&hid_host_connections, (btstack_linked_item_t*) connection);
btstack_memory_hid_host_connection_free(connection);
}
static void hid_host_handle_sdp_hid_descriptor_list(hid_host_connection_t * connection, uint16_t attribute_offset, uint8_t data){
// state machine
static uint16_t bytes_needed = 0;
static uint16_t bytes_received = 0;
static enum {
HID_DESCRIPTOR_LIST_ERROR,
HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_LIST_START,
HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_LIST_HEADER,
HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_START,
HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_HEADER,
HID_DESCRIPTOR_LIST_W4_ITEM_START,
HID_DESCRIPTOR_LIST_W4_ITEM_HEADER,
HID_DESCRIPTOR_LIST_W4_ITEM_COMPLETE,
HID_DESCRIPTOR_LIST_W4_STRING_HEADER,
HID_DESCRIPTOR_LIST_W4_STRING_COMPLETE,
HID_DESCRIPTOR_LIST_COMPLETE,
} state = HID_DESCRIPTOR_LIST_ERROR;
// init state machine
if (attribute_offset == 0){
state = HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_LIST_START;
bytes_received = 0;
}
// next step
bool stored;
bool error = false;
switch (state){
case HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_LIST_START:
hid_host_sdp_attribute_value[bytes_received++] = data;
if (de_get_element_type(hid_host_sdp_attribute_value) == DE_DES){
bytes_needed = de_get_header_size(hid_host_sdp_attribute_value);
state = HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_LIST_HEADER;
} else {
error = true;
}
break;
case HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_LIST_HEADER:
hid_host_sdp_attribute_value[bytes_received++] = data;
if (bytes_received == bytes_needed) {
bytes_received = 0;
state = HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_START;
}
break;
case HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_START:
hid_host_sdp_attribute_value[bytes_received++] = data;
if (de_get_element_type(hid_host_sdp_attribute_value) == DE_DES){
bytes_needed = de_get_header_size(hid_host_sdp_attribute_value);
state = HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_HEADER;
} else {
error = true;
}
break;
case HID_DESCRIPTOR_LIST_W4_DES_DESCRIPTOR_HEADER:
hid_host_sdp_attribute_value[bytes_received++] = data;
if (bytes_received == bytes_needed) {
bytes_received = 0;
state = HID_DESCRIPTOR_LIST_W4_ITEM_START;
}
break;
case HID_DESCRIPTOR_LIST_W4_ITEM_COMPLETE:
// ignore data for non-string item
bytes_received++;
if (bytes_received == bytes_needed) {
bytes_received = 0;
state = HID_DESCRIPTOR_LIST_W4_ITEM_START;
}
break;
case HID_DESCRIPTOR_LIST_W4_ITEM_START:
hid_host_sdp_attribute_value[bytes_received++] = data;
if (de_get_element_type(hid_host_sdp_attribute_value) == DE_STRING){
bytes_needed = de_get_header_size(hid_host_sdp_attribute_value);
state = HID_DESCRIPTOR_LIST_W4_STRING_HEADER;
} else {
bytes_needed = de_get_header_size(hid_host_sdp_attribute_value);
if (bytes_needed > 1){
state = HID_DESCRIPTOR_LIST_W4_ITEM_HEADER;
} else {
bytes_needed = de_get_len(hid_host_sdp_attribute_value);
state = HID_DESCRIPTOR_LIST_W4_ITEM_COMPLETE;
}
}
break;
case HID_DESCRIPTOR_LIST_W4_ITEM_HEADER:
hid_host_sdp_attribute_value[bytes_received++] = data;
if (bytes_received == bytes_needed) {
bytes_needed = de_get_len(hid_host_sdp_attribute_value);
state = HID_DESCRIPTOR_LIST_W4_ITEM_COMPLETE;
}
break;
case HID_DESCRIPTOR_LIST_W4_STRING_HEADER:
hid_host_sdp_attribute_value[bytes_received++] = data;
if (bytes_received == bytes_needed) {
bytes_received = 0;
bytes_needed = de_get_data_size(hid_host_sdp_attribute_value);
state = HID_DESCRIPTOR_LIST_W4_STRING_COMPLETE;
}
break;
case HID_DESCRIPTOR_LIST_W4_STRING_COMPLETE:
stored = hid_descriptor_storage_store(connection, data);
if (stored) {
bytes_received++;
if (bytes_received == bytes_needed) {
connection->hid_descriptor_status = ERROR_CODE_SUCCESS;
log_info_hexdump(&hid_host_descriptor_storage[connection->hid_descriptor_offset],
connection->hid_descriptor_len);
state = HID_DESCRIPTOR_LIST_COMPLETE;
}
} else {
error = true;
}
break;
case HID_DESCRIPTOR_LIST_ERROR:
case HID_DESCRIPTOR_LIST_COMPLETE:
// ignore data
break;
default:
btstack_unreachable();
break;
}
if (error){
log_info("Descriptor List invalid, state %u", (int) state);
bytes_received = 0;
bytes_needed = 0;
state = HID_DESCRIPTOR_LIST_ERROR;
connection->hid_descriptor_status = ERROR_CODE_MEMORY_CAPACITY_EXCEEDED;
}
}
static void hid_host_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) {
UNUSED(packet_type);
UNUSED(channel);
@ -422,6 +552,13 @@ static void hid_host_handle_sdp_client_query_result(uint8_t packet_type, uint16_
attribute_id = sdp_event_query_attribute_byte_get_attribute_id(packet);
attribute_offset = sdp_event_query_attribute_byte_get_data_offset(packet);
attribute_data = sdp_event_query_attribute_byte_get_data(packet);
// process BLUETOOTH_ATTRIBUTE_HID_DESCRIPTOR_LIST with state machine
if (attribute_id == BLUETOOTH_ATTRIBUTE_HID_DESCRIPTOR_LIST){
hid_host_handle_sdp_hid_descriptor_list(connection, attribute_offset, attribute_data);
break;
}
if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= hid_host_sdp_attribute_value_buffer_size) {
hid_host_sdp_attribute_value[attribute_offset] = attribute_data;
@ -474,32 +611,6 @@ static void hid_host_handle_sdp_client_query_result(uint8_t packet_type, uint16_
}
break;
case BLUETOOTH_ATTRIBUTE_HID_DESCRIPTOR_LIST:
for (des_iterator_init(&attribute_list_it, hid_host_sdp_attribute_value); des_iterator_has_more(&attribute_list_it); des_iterator_next(&attribute_list_it)) {
if (des_iterator_get_type(&attribute_list_it) != DE_DES) continue;
des_element = des_iterator_get_element(&attribute_list_it);
for (des_iterator_init(&additional_des_it, des_element); des_iterator_has_more(&additional_des_it); des_iterator_next(&additional_des_it)) {
if (des_iterator_get_type(&additional_des_it) != DE_STRING) continue;
element = des_iterator_get_element(&additional_des_it);
const uint8_t * descriptor = de_get_string(element);
uint16_t descriptor_len = de_get_data_size(element);
uint16_t i;
bool stored = false;
connection->hid_descriptor_status = ERROR_CODE_SUCCESS;
for (i = 0; i < descriptor_len; i++){
stored = hid_descriptor_storage_store(connection, descriptor[i]);
if (!stored){
connection->hid_descriptor_status = ERROR_CODE_MEMORY_CAPACITY_EXCEEDED;
break;
}
}
}
}
break;
case BLUETOOTH_ATTRIBUTE_HIDSSR_HOST_MAX_LATENCY:
if (de_get_element_type(hid_host_sdp_attribute_value) == DE_UINT) {
uint16_t host_max_latency;