103 lines
2.7 KiB
JavaScript
103 lines
2.7 KiB
JavaScript
'use strict';
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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var _crypto = require('crypto');
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var _crypto2 = _interopRequireDefault(_crypto);
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var _defs = require('./defs');
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var _utils = require('../utils');
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
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class ObfsRandomPaddingPreset extends _defs.IPreset {
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constructor(...args) {
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var _temp;
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return _temp = super(...args), this._adBuf = null, _temp;
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}
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onInit() {
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this._adBuf = new _utils.AdvancedBuffer({ getPacketLength: this.onReceiving.bind(this) });
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this._adBuf.on('data', this.onChunkReceived.bind(this));
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}
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onDestroy() {
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this._adBuf.clear();
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this._adBuf = null;
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}
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getRandomBytesLength(dataLen) {
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if (dataLen > 1440) {
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return 0;
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}
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const rand = _crypto2.default.randomBytes(1)[0];
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let random_bytes_len;
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if (dataLen > 1300) {
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random_bytes_len = rand % 31;
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} else if (dataLen > 900) {
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random_bytes_len = rand % 127;
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} else if (dataLen > 400) {
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random_bytes_len = rand % 521;
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} else {
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random_bytes_len = rand % 1021;
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}
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return random_bytes_len;
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}
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beforeOut({ buffer }) {
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const chunks = (0, _utils.getRandomChunks)(buffer, 0x3fff, 0xffff).map(data => {
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const pLen = this.getRandomBytesLength(data.length);
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const padding = _crypto2.default.randomBytes(pLen);
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return Buffer.concat([(0, _utils.numberToBuffer)(pLen, 1), padding, (0, _utils.numberToBuffer)(data.length), data]);
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});
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return Buffer.concat(chunks);
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}
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beforeIn({ buffer, next }) {
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this._adBuf.put(buffer, { next });
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}
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onReceiving(buffer) {
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if (buffer.length < 3) {
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return;
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}
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const pLen = buffer[0];
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if (buffer.length < 1 + pLen + 2) {
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return;
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}
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const dLen = buffer.readUInt16BE(1 + pLen);
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if (buffer.length < 1 + pLen + 2 + dLen) {
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return;
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}
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return 1 + pLen + 2 + dLen;
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}
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onChunkReceived(chunk, { next }) {
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const pLen = chunk[0];
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next(chunk.slice(1 + pLen + 2));
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}
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beforeOutUdp({ buffer }) {
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const pLen = _crypto2.default.randomBytes(1)[0] % 128;
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const padding = _crypto2.default.randomBytes(pLen);
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return Buffer.concat([(0, _utils.numberToBuffer)(pLen, 1), padding, buffer]);
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}
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beforeInUdp({ buffer, fail }) {
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if (buffer.length < 1) {
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return fail(`too short to get PaddingLen, len=${buffer.length} dump=${buffer.toString('hex')}`);
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}
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const pLen = buffer[0];
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if (buffer.length < 1 + pLen) {
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return fail(`too short to drop Padding, len=${buffer.length} dump=${buffer.slice(0, 60).toString('hex')}`);
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}
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return buffer.slice(1 + pLen);
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}
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}
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exports.default = ObfsRandomPaddingPreset; |