mirror of https://github.com/gchq/CyberChef.git
54 lines
1.2 KiB
JavaScript
54 lines
1.2 KiB
JavaScript
/**
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* @author n1474335 [n1474335@gmail.com]
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* @copyright Crown Copyright 2016
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* @license Apache-2.0
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*/
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import Operation from "../Operation";
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import Utils from "../Utils";
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/**
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* TCP/IP Checksum operation
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*/
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class TCPIPChecksum extends Operation {
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/**
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* TCPIPChecksum constructor
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*/
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constructor() {
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super();
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this.name = "TCP/IP Checksum";
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this.module = "Crypto";
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this.description = "Calculates the checksum for a TCP (Transport Control Protocol) or IP (Internet Protocol) header from an input of raw bytes.";
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this.infoURL = "https://wikipedia.org/wiki/IPv4_header_checksum";
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this.inputType = "byteArray";
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this.outputType = "string";
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this.args = [];
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}
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/**
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* @param {byteArray} input
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* @param {Object[]} args
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* @returns {string}
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*/
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run(input, args) {
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let csum = 0;
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for (let i = 0; i < input.length; i++) {
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if (i % 2 === 0) {
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csum += (input[i] << 8);
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} else {
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csum += input[i];
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}
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}
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csum = (csum >> 16) + (csum & 0xffff);
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return Utils.hex(0xffff - csum);
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}
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}
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export default TCPIPChecksum;
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