feat: add bootloader DFU protocol validation

This commit is contained in:
2026-04-29 17:56:32 +02:00
parent eb26c759e8
commit b673c9100d
7 changed files with 534 additions and 86 deletions

View File

@ -3,6 +3,39 @@ import 'dart:typed_data';
import 'package:abawo_bt_app/model/shifter_types.dart';
const int _startPayloadLength = 11;
const int _bootloaderStartPayloadLength = 19;
class BootloaderDfuStartPayload {
const BootloaderDfuStartPayload({
required this.totalLength,
required this.imageCrc32,
this.appStart = universalShifterDfuAppStart,
this.imageVersion = 0,
required this.sessionId,
required this.flags,
});
final int totalLength;
final int imageCrc32;
final int appStart;
final int imageVersion;
final int sessionId;
final int flags;
}
class BootloaderDfuDataFrame {
const BootloaderDfuDataFrame({
required this.sessionId,
required this.offset,
required this.payloadLength,
required this.bytes,
});
final int sessionId;
final int offset;
final int payloadLength;
final Uint8List bytes;
}
class DfuStartPayload {
const DfuStartPayload({
@ -135,3 +168,145 @@ class DfuProtocol {
return value & 0xFF;
}
}
class BootloaderDfuProtocol {
const BootloaderDfuProtocol._();
static Uint8List encodeStartPayload(BootloaderDfuStartPayload payload) {
final data = ByteData(_bootloaderStartPayloadLength);
data.setUint8(0, universalShifterDfuOpcodeStart);
data.setUint32(1, payload.totalLength, Endian.little);
data.setUint32(5, payload.imageCrc32, Endian.little);
data.setUint32(9, payload.appStart, Endian.little);
data.setUint32(13, payload.imageVersion, Endian.little);
data.setUint8(17, payload.sessionId & 0xFF);
data.setUint8(18, payload.flags & 0xFF);
return data.buffer.asUint8List();
}
static Uint8List encodeFinishPayload(int sessionId) {
return Uint8List.fromList([
universalShifterDfuOpcodeFinish,
sessionId & 0xFF,
]);
}
static Uint8List encodeAbortPayload(int sessionId) {
return Uint8List.fromList([
universalShifterDfuOpcodeAbort,
sessionId & 0xFF,
]);
}
static Uint8List encodeGetStatusPayload() {
return Uint8List.fromList([universalShifterDfuOpcodeGetStatus]);
}
static BootloaderDfuDataFrame buildDataFrame({
required List<int> imageBytes,
required int sessionId,
required int offset,
int payloadSize = universalShifterBootloaderDfuMaxPayloadSizeBytes,
}) {
if (offset < 0 || offset >= imageBytes.length) {
throw RangeError.range(offset, 0, imageBytes.length - 1, 'offset');
}
if (payloadSize <= 0 ||
payloadSize > universalShifterBootloaderDfuMaxPayloadSizeBytes) {
throw RangeError.range(
payloadSize,
1,
universalShifterBootloaderDfuMaxPayloadSizeBytes,
'payloadSize',
);
}
final remaining = imageBytes.length - offset;
final payloadLength = remaining < payloadSize ? remaining : payloadSize;
final payloadEnd = offset + payloadLength;
final payload = imageBytes.sublist(offset, payloadEnd);
final frame = Uint8List(
universalShifterBootloaderDfuDataHeaderSizeBytes + payloadLength,
);
frame[0] = sessionId & 0xFF;
final data = ByteData.view(frame.buffer);
data.setUint32(1, offset, Endian.little);
data.setUint32(5, crc32(payload), Endian.little);
frame.setRange(
universalShifterBootloaderDfuDataHeaderSizeBytes,
universalShifterBootloaderDfuDataHeaderSizeBytes + payloadLength,
payload,
);
return BootloaderDfuDataFrame(
sessionId: sessionId & 0xFF,
offset: offset,
payloadLength: payloadLength,
bytes: frame,
);
}
static List<BootloaderDfuDataFrame> buildDataFrames({
required List<int> imageBytes,
required int sessionId,
int payloadSize = universalShifterBootloaderDfuMaxPayloadSizeBytes,
}) {
final frames = <BootloaderDfuDataFrame>[];
var offset = 0;
while (offset < imageBytes.length) {
final frame = buildDataFrame(
imageBytes: imageBytes,
sessionId: sessionId,
offset: offset,
payloadSize: payloadSize,
);
frames.add(frame);
offset += frame.payloadLength;
}
return frames;
}
static int maxPayloadSizeForMtu(int negotiatedMtu) {
final writePayloadBytes =
negotiatedMtu - universalShifterAttWriteOverheadBytes;
final availablePayload =
writePayloadBytes - universalShifterBootloaderDfuDataHeaderSizeBytes;
if (availablePayload <= 0) {
return 0;
}
if (availablePayload > universalShifterBootloaderDfuMaxPayloadSizeBytes) {
return universalShifterBootloaderDfuMaxPayloadSizeBytes;
}
return availablePayload;
}
static DfuBootloaderStatus parseStatusPayload(List<int> payload) {
if (payload.length != universalShifterBootloaderDfuStatusSizeBytes) {
throw const FormatException(
'DFU status payload must be exactly 6 bytes.');
}
final data = ByteData.sublistView(Uint8List.fromList(payload));
final rawCode = data.getUint8(0);
return DfuBootloaderStatus(
code: DfuBootloaderStatusCode.fromRaw(rawCode),
rawCode: rawCode,
sessionId: data.getUint8(1),
expectedOffset: data.getUint32(2, Endian.little),
);
}
static const int crc32Initial = DfuProtocol.crc32Initial;
static int crc32Update(int crc, List<int> bytes) {
return DfuProtocol.crc32Update(crc, bytes);
}
static int crc32Finalize(int crc) {
return DfuProtocol.crc32Finalize(crc);
}
static int crc32(List<int> bytes) {
return DfuProtocol.crc32(bytes);
}
}

View File

@ -75,7 +75,7 @@ class FirmwareFileSelectionService {
final FirmwareFilePicker _filePicker;
final SessionIdGenerator _sessionIdGenerator;
Future<FirmwareFileSelectionResult> selectAndPrepareDfuV1() async {
Future<FirmwareFileSelectionResult> selectAndPrepareBootloaderDfu() async {
final FirmwarePickerSelection? selection;
try {
selection = await _filePicker.pickFirmwareFile();
@ -127,15 +127,30 @@ class FirmwareFileSelectionService {
);
}
final metadata = DfuV1FirmwareMetadata(
final imageValidationFailure = _validateBootloaderImage(
selection.fileBytes,
fileName,
);
if (imageValidationFailure != null) {
return FirmwareFileSelectionResult.failed(imageValidationFailure);
}
final vectorStackPointer = _readLeU32(selection.fileBytes, 0);
final vectorReset = _readLeU32(selection.fileBytes, 4);
final metadata = BootloaderDfuFirmwareMetadata(
totalLength: selection.fileBytes.length,
crc32: DfuProtocol.crc32(selection.fileBytes),
crc32: BootloaderDfuProtocol.crc32(selection.fileBytes),
appStart: universalShifterDfuAppStart,
imageVersion: 0,
sessionId: _sessionIdGenerator() & 0xFF,
flags: universalShifterDfuFlagNone,
vectorStackPointer: vectorStackPointer,
vectorReset: vectorReset,
);
return FirmwareFileSelectionResult.success(
DfuV1PreparedFirmware(
BootloaderDfuPreparedFirmware(
fileName: fileName,
filePath: selection.filePath,
fileBytes: selection.fileBytes,
@ -148,6 +163,58 @@ class FirmwareFileSelectionService {
return fileName.toLowerCase().endsWith('.bin');
}
FirmwareSelectionFailure? _validateBootloaderImage(
Uint8List imageBytes,
String fileName,
) {
if (imageBytes.length < universalShifterDfuMinimumImageLengthBytes) {
return FirmwareSelectionFailure(
reason: FirmwareSelectionFailureReason.imageTooSmall,
message:
'Selected firmware file "$fileName" is too small for a bootloader application image. Need at least $universalShifterDfuMinimumImageLengthBytes bytes.',
);
}
if (imageBytes.length > universalShifterDfuAppSlotSizeBytes) {
return FirmwareSelectionFailure(
reason: FirmwareSelectionFailureReason.imageTooLarge,
message:
'Selected firmware file "$fileName" is ${imageBytes.length} bytes, which exceeds the $universalShifterDfuAppSlotSizeBytes byte application slot.',
);
}
final vectorStackPointer = _readLeU32(imageBytes, 0);
final vectorReset = _readLeU32(imageBytes, 4);
final resetAddress = vectorReset & ~0x1;
final imageEnd = universalShifterDfuAppStart + imageBytes.length;
if (vectorStackPointer < universalShifterDfuRamStart ||
vectorStackPointer > universalShifterDfuRamEnd ||
(vectorStackPointer & 0x3) != 0) {
return FirmwareSelectionFailure(
reason: FirmwareSelectionFailureReason.invalidVectorTable,
message:
'Selected firmware file "$fileName" has an invalid initial stack pointer (0x${vectorStackPointer.toRadixString(16).padLeft(8, '0').toUpperCase()}).',
);
}
if ((vectorReset & 0x1) == 0 ||
resetAddress < universalShifterDfuAppStart + 8 ||
resetAddress >= imageEnd) {
return FirmwareSelectionFailure(
reason: FirmwareSelectionFailureReason.invalidVectorTable,
message:
'Selected firmware file "$fileName" has an invalid reset vector (0x${vectorReset.toRadixString(16).padLeft(8, '0').toUpperCase()}). Ensure the image starts at application address 0x${universalShifterDfuAppStart.toRadixString(16).padLeft(8, '0').toUpperCase()}.',
);
}
return null;
}
int _readLeU32(Uint8List bytes, int offset) {
return ByteData.sublistView(bytes).getUint32(offset, Endian.little);
}
static int _randomSessionId() {
return Random.secure().nextInt(256);
}