netkitty/dist/lib/pcap/PCAPGenerator.js

Network tools kit

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.GeneratePCAPHeader = GeneratePCAPHeader;
exports.GeneratePCAPData = GeneratePCAPData;
exports.GeneratePCAP = GeneratePCAP;
/**
 * 由pcap-generator库改写
 * @see:https://github.com/onomondo/pcap-generator/tree/master
 */
const bignumber_js_1 = __importDefault(require("bignumber.js"));
const headerOptions = {
    majorVersion: 2,
    minorVersion: 4,
    gmtOffset: 0,
    timestampAccuracy: 0,
    snapshotLength: 65535,
    linkLayerType: 1
};
function generate(packets) {
    const globalHeader = GeneratePCAPHeader();
    const packetsBuffer = Buffer.concat(packets.map((packet) => GeneratePCAPData(packet)));
    return Buffer.concat([globalHeader, packetsBuffer]);
}
/**
 * Converts a timestamp in milliseconds to an integer of the seconds part and an integer of the microseconds part
 *
 * @param ms
 */
function convertMillisecond2Microsecond(ms) {
    const [seconds, microseconds] = new bignumber_js_1.default(ms).dividedBy(1000).toFixed(6).split('.').map(value => parseInt(value));
    return [seconds, microseconds];
}
function makeLessThanAMillion(i) {
    while (i > 1000000) {
        i = Math.floor(i / 10);
    }
    return i;
}
/**
 * Generate pcap file header's buffer
 * @constructor
 */
function GeneratePCAPHeader() {
    const globalHeader = Buffer.alloc(24);
    globalHeader.writeUInt32BE(2712847316, 0); // 4
    globalHeader.writeUInt16BE(headerOptions.majorVersion, 4); // 2
    globalHeader.writeUInt16BE(headerOptions.minorVersion, 6); // 2
    globalHeader.writeInt32BE(headerOptions.gmtOffset, 8); // 4
    globalHeader.writeUInt32BE(headerOptions.timestampAccuracy, 12); // 4
    globalHeader.writeUInt32BE(headerOptions.snapshotLength, 16); // 4
    globalHeader.writeUInt32BE(headerOptions.linkLayerType, 20); // 4
    return globalHeader;
}
/**
 * Generate single record data in pcap file
 * @param packet
 * @constructor
 */
function GeneratePCAPData(packet) {
    const packetHeader = Buffer.alloc(16);
    let seconds;
    let microseconds;
    if (packet.microsecond) {
        seconds = packet.microsecond.seconds;
        microseconds = packet.microsecond.microseconds;
    }
    else {
        if (packet.timestamp) {
            [seconds, microseconds] = convertMillisecond2Microsecond(packet.timestamp);
        }
        else {
            seconds = 0;
            microseconds = 0;
        }
    }
    packetHeader.writeUInt32BE(seconds, 0); // 4
    if (packet.microsecond) {
        packetHeader.writeUInt32BE(microseconds, 4); // 4 - if in microsecond precision then remove excess of 1,000,000 (see documentation)
    }
    else {
        packetHeader.writeUInt32BE(makeLessThanAMillion(microseconds), 4); // 4 - if in microsecond precision then remove excess of 1,000,000 (see documentation)
    }
    packetHeader.writeUInt32BE(packet.buffer.length, 8); // 4
    packetHeader.writeUInt32BE(packet.buffer.length, 12); // 4
    return Buffer.concat([packetHeader, packet.buffer]);
}
/**
 * Generate whole pcap file buffer data
 * @param packets
 * @constructor
 */
function GeneratePCAP(packets = []) {
    return generate(packets.map((packet) => ({
        timestamp: packet.timestamp,
        microsecond: packet.microsecond,
        buffer: Buffer.from(packet.frameBase64Data, 'base64')
    })));
}