221 lines
6.5 KiB
JavaScript
221 lines
6.5 KiB
JavaScript
;(function (exports) {
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'use strict';
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var pdns = exports.DNS_PARSER = {};
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var classes = exports.DNS_CLASSES || require('./dns.classes.js').DNS_CLASSES;
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var types = exports.DNS_TYPES || require('./dns.types.js').DNS_TYPES;
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// Order http://www.zytrax.com/books/dns/ch15/
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var packet = {};
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pdns.unpackHeader = function (i) {
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// i is one element from a Uint16Array (as a 16-bit unsigned integer)
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var header = {
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id: 0 // added here to preserve console.log order
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, qr: (i & 0x8000) >> 15 // Query Response (0 is question, 1 is response)
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, opcode: (i & 0x7800) >> 11 // 0 is question
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, aa: (i & 0x400) >> 10 // Authoritative Answer (response-only)
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, tc: (i & 0x200) >> 9 // TrunCated - expect another packet with same (?) id
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, rd: (i & 0x100) >> 8 // Recursion Desired
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, ra: (i & 0x80) >> 7
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, res1: (i & 0x40) >> 6 // z
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, res2: (i & 0x20) >> 5 // ad
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, res3: (i & 0x10) >> 4 // cd
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, rcode: (i & 0xF) // Error Code (response-only)
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};
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return header;
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};
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pdns._unpackLabels = exports.DNS_UNPACK_LABELS || require('./dns.unpack-labels.js').DNS_UNPACK_LABELS;
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pdns.unpack = function (ab) {
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if (ab.buffer) {
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ab = ab.buffer;
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}
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// SANITY Check
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if (ab.byteLength < 12) {
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throw new Error(
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"A DNS header has a minimum length of 12 bytes but this packet has only " + ab.byteLength + "bytes."
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);
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}
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// DO: new Uint8Array(arrayBuffer);
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// DO NOT: Uint8Array.from(arrayBuffer); // WILL NOT WORK
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// DO: new DataView(arrayBuffer).getUint16(7, false);
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// DO NOT: arrayBuffer.slice();
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//
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// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer
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// https://developer.mozilla.org/en-US/docs/Web/API/ArrayBufferView
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// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
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// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/slice
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// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView
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var dv = new DataView(ab);
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var id = dv.getUint16(0, false);
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packet.header = pdns.unpackHeader(dv.getUint16(2, false));
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packet.qdcount = dv.getUint16(4, false); // query count
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packet.ancount = dv.getUint16(6, false); // answer count
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packet.nscount = dv.getUint16(8, false); // authority count
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packet.arcount = dv.getUint16(10, false); // additional count
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var total = 12;
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var i;
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var rec;
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var ui8 = new Uint8Array(ab);
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// TODO move to pdns.unpackQuestion to make testable
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function unpackQuestion(ab, dv, ui8, total) {
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var ototal = total;
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var q = pdns._unpackLabels(ui8, total, {
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name: '' // ex: daplie.com
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, type: 0 // ex: 1
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, typeName: '' // ex: A
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, class: 0 // ex: 1
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, className: '' // ex: IN
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, byteLength: 0 // the total byte length (including pointers, but not their labels)
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, labels: [] // an array of the labels individually
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, cpcount: 0 // the number of compression pointers traversed
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});
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//console.log('unpackQuestion QNAME:');
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//console.log(q);
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total += q.byteLength;
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if (ab.byteLength - total < 4) {
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// console.error(str.join(''));
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throw new Error(
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"Expected a 2-byte QTYPE and 2-byte QCLASS following " + total + "-byte QNAME"
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+ " but packet itself has " + (ab.byteLength - total) + " bytes remaining"
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);
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}
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q.type = dv.getUint16(total, false);
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total += 2;
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q.class = dv.getUint16(total, false);
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total += 2;
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q.byteLength = total - ototal;
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q.className = classes[q.class];
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q.typeName = types[q.type];
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return q;
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}
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function unpackAnswer(ab, dv, ui8, total) {
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var ototal = total;
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var err;
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var q = pdns._unpackLabels(ui8, total, {
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name: ''
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, type: 0
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, typeName: ''
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, class: 0
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, className: ''
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, byteLength: 0
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, labels: []
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, cpcount: 0
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, rdstart: 0
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//, rdata: 0
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, rdlength: 0
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});
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//console.log('unpackAnswer [Q]NAME:');
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//console.log(q);
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total += q.byteLength;
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q.className = classes[q.class];
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q.typeName = types[q.type];
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if (ab.byteLength - total < 10) {
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// console.error(str.join(''));
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//console.error(JSON.stringify(packet, null, 1));
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//console.error(JSON.stringify(q, null, 1));
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err = new Error(
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"Expected a 2-byte QTYPE, 2-byte QCLASS, 4-byte TTL, and 2-byte RDLENGTH following " + total + "-byte QNAME"
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+ " but packet itself has " + (ab.byteLength - total) + " bytes remaining"
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);
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err.packet = packet;
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err.record = q;
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throw err;
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}
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q.type = dv.getUint16(total, false);
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total += 2;
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q.class = dv.getUint16(total, false);
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total += 2;
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q.ttl = dv.getUint32(total, false);
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total += 4;
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q.rdlength = dv.getUint16(total, false);
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total += 2;
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q.className = classes[q.class];
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q.typeName = types[q.type];
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// TODO actually parse RDATA
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q.rdstart = total;
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// console.log('q.rdata', q.rdlength, 'bytes:');
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// console.log(new Uint8Array(ab).slice(total, total + q.rdlength));
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//q.rdata = Array.prototype.slice.apply(q.rdata);
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//q.rdend = q.rdstart + q.rdlength;
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total += q.rdlength;
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q.byteLength = total - ototal;
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return q;
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}
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packet.header.id = id;
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console.log('qdcount', packet.qdcount);
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packet.question = [];
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for (i = 0; i < packet.qdcount; i += 1) {
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rec = unpackQuestion(ab, dv, ui8, total);
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total += rec.byteLength;
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packet.question.push(rec);
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}
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console.log('ancount', packet.ancount);
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packet.answer = [];
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for (i = 0; i < packet.ancount; i += 1) {
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rec = unpackAnswer(ab, dv, ui8, total);
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total += rec.byteLength;
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packet.answer.push(rec);
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}
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console.log('nscount', packet.nscount);
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packet.authority = [];
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for (i = 0; i < packet.nscount; i += 1) {
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rec = unpackAnswer(ab, dv, ui8, total);
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total += rec.byteLength;
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packet.authority.push(rec);
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}
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console.log('arcount', packet.arcount);
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packet.additional = [];
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for (i = 0; i < packet.arcount; i += 1) {
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rec = unpackAnswer(ab, dv, ui8, total);
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total += rec.byteLength;
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packet.additional.push(rec);
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}
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if (ab.byteLength !== total) {
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throw new Error(
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"Parsed " + total + " bytes, but packet is " + ab.byteLength + " bytes."
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);
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}
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packet.byteLength = total;
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return packet;
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};
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pdns.unpackRdata = exports.DNS_RDATA_PARSE || require('./dns.rdata.parse.js').DNS_RDATA_PARSE;
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}('undefined' !== typeof window ? window : exports));
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