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debug:修复WebSocket数据不完整导致解析异常的问题 #322

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debug:修复WebSocket数据不完整导致解析异常的问题 #322

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6 changes: 1 addition & 5 deletions lib/network/handler.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -329,11 +329,7 @@ class WebSocketChannelHandler extends ChannelHandler<Uint8List> {
void channelRead(ChannelContext channelContext, Channel channel, Uint8List msg) {
proxyChannel.write(msg);
WebSocketFrame? frame;
try {
frame = decoder.decode(msg);
} catch (e) {
log.e("websocket decode error", error: e);
}
frame = decoder.decode(msg);
if (frame == null) {
return;
}
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151 changes: 100 additions & 51 deletions lib/network/http/websocket.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,8 @@ import 'dart:io';
import 'dart:math';
import 'dart:typed_data';

import '../util/logger.dart';

class WebSocketFrame {
final bool fin;

Expand Down Expand Up @@ -67,92 +69,138 @@ class WebSocketFrame {
}
}

class WebSocketHeader {
final bool fin; // 当前帧是否结束
final int rsv; // 是否压缩
final int opcode; //4bit 当前帧类型
final bool mask; //1bit 是否有掩码
final int maskingKey; // 掩码
final int payloadStart; // 消息体起始位置
final int payloadLength; // 消息体大小

WebSocketHeader({
required this.fin,
required this.rsv,
required this.opcode,
required this.mask,
required this.maskingKey,
required this.payloadStart,
required this.payloadLength,
});
}

///websocket 解码器
class WebSocketDecoder {
List<int> buffer = []; // 单独创建一个缓存,以解决数据帧不完整的问题

WebSocketFrame? decode(Uint8List byteBuf) {
var frame = _parseWebSocketFrame(byteBuf);
WebSocketFrame? frame;
buffer.addAll(byteBuf); // 所有的数据都从缓存中读取
try {
//先解析WebSocket Header
if (buffer.length < 2) {
// logger.w("报文缓存中的大小不够,无法解析Socket头 => ${buffer.length}");
return null;
}
var reader = ByteData.sublistView(Uint8List.fromList(buffer));
WebSocketHeader frameHeader = parseWebSocketHeader(reader);
// 大小不足时不解析Frame
if (buffer.length < frameHeader.payloadStart + frameHeader.payloadLength) {
return null;
}
// 处理报文
var payloadData = Uint8List.fromList(buffer).sublist(
frameHeader.payloadStart,
frameHeader.payloadStart + frameHeader.payloadLength);
// 先解掩码
if (frameHeader.mask) {
payloadData = unmaskPayload(payloadData, frameHeader.maskingKey);
}
// 再解压
if (frameHeader.rsv == 1) {
payloadData = decompress(payloadData);
}
// 构建Frame
frame = WebSocketFrame(
fin: frameHeader.fin,
opcode: frameHeader.opcode,
mask: frameHeader.mask,
payloadLength: frameHeader.payloadLength,
maskingKey: frameHeader.maskingKey,
payloadData: payloadData);
// 整理buffer
buffer =
buffer.sublist(frameHeader.payloadStart + frameHeader.payloadLength);
} catch (e, s) {
logger.e("websocket decode error", error: e, stackTrace: s);
}
return frame;
}

bool canParseWebSocketFrame(Uint8List data) {
if (data.length < 2) {
return false;
}

var reader = ByteData.sublistView(data);
WebSocketHeader parseWebSocketHeader(ByteData reader) {
var fin = reader.getUint8(0) >> 7;
//解析 rsv1 todo - 待支持rsv2,rsv3
var rsv1 = (reader.getUint8(0) >> 6) & 0x01;

var opcode = reader.getUint8(0) & 0x0f;
if (opcode > 0xA) {
return false;
}

var mask = reader.getUint8(1) >> 7;
int payloadStart = 2;
if (mask == 1) {
payloadStart += 4;
}

var payloadLength = reader.getUint8(1) & 0x7f;

int payloadStart = 2;

if (payloadLength == 126) {
payloadLength = reader.getUint16(2, Endian.big);
payloadStart += 2;
} else if (payloadLength == 127) {
payloadLength = reader.getUint64(2, Endian.big);
payloadStart += 8;
}
var maskingKey = 0;
if (mask == 1) {
maskingKey = reader.getUint32(payloadStart);
payloadStart += 4;
}
return WebSocketHeader(
fin: fin == 1,
rsv: rsv1,
opcode: opcode,
mask: mask == 1,
maskingKey: maskingKey,
payloadStart: payloadStart,
payloadLength: payloadLength);
}

if (data.length < payloadStart + payloadLength) {
bool canParseWebSocketFrame(Uint8List data) {
if (data.length < 2) {
return false;
}
return true;
}

WebSocketFrame _parseWebSocketFrame(Uint8List data) {
var reader = ByteData.sublistView(data);

var fin = reader.getUint8(0) >> 7;
//解析 rsv1
var rsv1 = (reader.getUint8(0) >> 6) & 0x01;

var opcode = reader.getUint8(0) & 0x0f;
if (opcode > 0xA) {
return false; // opCode超出范围说明是异常的
}

var mask = reader.getUint8(1) >> 7;

var payloadLength = reader.getUint8(1) & 0x7f;

int payloadStart = 2;
if (mask == 1) {
payloadStart += 4;
}

var payloadLength = reader.getUint8(1) & 0x7f;
if (payloadLength == 126) {
payloadLength = reader.getUint16(2);
payloadStart += 2;
} else if (payloadLength == 127) {
payloadLength = reader.getUint64(2);
payloadStart += 8;
}

var maskingKey = 0;
if (mask == 1) {
maskingKey = reader.getUint32(payloadStart);
payloadStart += 4;
}

var payloadData = data.sublist(payloadStart, min(payloadStart + payloadLength, data.length));

//根据maskKey解密内容
if (mask == 1) {
payloadData = unmaskPayload(payloadData, maskingKey);
}

if (rsv1 == 1) {
//inflate
payloadData = decompress(payloadData);
if (data.length < payloadStart + payloadLength) {
return false;
}
return WebSocketFrame(
fin: fin == 1,
opcode: opcode,
mask: mask == 1,
maskingKey: maskingKey,
payloadLength: payloadLength,
payloadData: payloadData,
);
return true;
}

ZLibDecoder? _decoder;
Expand All @@ -161,6 +209,7 @@ class WebSocketDecoder {

Uint8List decompress(Uint8List msg) {
try {
// todo - 这个方法没有办法正确解析rsv1为1的payload.
return Uint8List.fromList(_ensureDecoder().convert(msg));
} catch (e) {
return msg;
Expand Down