mirror of
https://github.com/Ylianst/MeshCentral.git
synced 2024-11-30 23:12:13 +03:00
112 lines
2.8 KiB
JavaScript
112 lines
2.8 KiB
JavaScript
/*
|
|
* Copyright (c) 2014-2015 Sylvain Peyrefitte
|
|
*
|
|
* This file is part of node-rdpjs.
|
|
*
|
|
* node-rdpjs is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
var type = require('../core').type;
|
|
var log = require('../core').log;
|
|
var error = require('../core').error;
|
|
|
|
/**
|
|
* Parse tag(T) field of BER TLV
|
|
* And check with expected tag
|
|
* @param s {type.Stream}
|
|
* @param tag {spec.tag}
|
|
* @returns {Boolean} True for valid tag matching
|
|
*/
|
|
function decodeTag(s, tag) {
|
|
var nextTag = new type.UInt8().read(s).value;
|
|
if (tag.tagNumber > 30) {
|
|
nextTagNumber = new type.UInt8().read(s).value;
|
|
}
|
|
else {
|
|
nextTagNumber = nextTag & 0x1F;
|
|
}
|
|
|
|
return ((nextTag & 0xE0) === (tag.tagClass | tag.tagFormat)) && (nextTagNumber === tag.tagNumber);
|
|
};
|
|
|
|
/**
|
|
* Parse length(L) field of BER TLV
|
|
* @param s {type.Stream}
|
|
* @returns {integer}
|
|
*/
|
|
function decodeLength(s) {
|
|
var size = new type.UInt8().read(s).value;
|
|
if(size & 0x80) {
|
|
size &= ~0x80;
|
|
if(size === 1) {
|
|
size = new type.UInt8().read(s).value;
|
|
}
|
|
else if(size === 2) {
|
|
size = new type.UInt16Be().read(s).value;
|
|
}
|
|
else{
|
|
throw new error.ProtocolError('NODE_RDP_ASN1_BER_INVALID_LENGTH');
|
|
}
|
|
}
|
|
return size;
|
|
};
|
|
|
|
/**
|
|
* Decode tuple TLV (Tag Length Value) of BER
|
|
* @param s {type.Stream}
|
|
* @param tag {spec.Asn1Tag} expected tag
|
|
* @returns {type.BinaryString} Value of tuple
|
|
*/
|
|
function decode(s, tag) {
|
|
if (!decodeTag(s, tag)) {
|
|
throw new error.ProtocolError('NODE_RDP_ASN1_BER_INVALID_TAG');
|
|
}
|
|
var length = decodeLength(s);
|
|
|
|
if (length === 0) {
|
|
return new type.Stream(0);
|
|
}
|
|
return new type.BinaryString(null,{ readLength : new type.CallableValue(length) }).read(s);
|
|
};
|
|
|
|
function encodeTag(tag) {
|
|
if(tag.tagNumber > 30) {
|
|
return new type.Component([new type.UInt8(tag.tagClass | tag.tagFormat | 0x1F), new type.UInt8(tag.tagNumber)]);
|
|
}
|
|
else {
|
|
return new type.UInt8((tag.tagClass | tag.tagFormat) | (tag.tagNumber & 0x1F));
|
|
}
|
|
}
|
|
|
|
function encodeLength(length) {
|
|
if(length > 0x7f) {
|
|
return new type.Component([new type.UInt8(0x82), new type.UInt16Be(length)]);
|
|
}
|
|
else {
|
|
return new type.UInt8(length);
|
|
}
|
|
}
|
|
|
|
function encode(tag, buffer) {
|
|
return new type.Component([encodeTag(tag), encodeLength(buffer.size()), buffer]);
|
|
}
|
|
|
|
/**
|
|
* Module Export
|
|
*/
|
|
module.exports = {
|
|
decode : decode,
|
|
encode : encode
|
|
};
|