Function parseDNSPacket

test/common/dns.js:52–165

(buffer)

}

function parseDNSPacket(buffer) {
  assert.ok(buffer.length > 12);

  const parsed = {
    id: buffer.readUInt16BE(0),
    flags: buffer.readUInt16BE(2),
  };

  const counts = [
    ['questions', buffer.readUInt16BE(4)],
    ['answers', buffer.readUInt16BE(6)],
    ['authorityAnswers', buffer.readUInt16BE(8)],
    ['additionalRecords', buffer.readUInt16BE(10)],
  ];

  let offset = 12;
  for (const [ sectionName, count ] of counts) {
    parsed[sectionName] = [];
    for (let i = 0; i < count; ++i) {
      const { nread, domain } = readDomainFromPacket(buffer, offset);
      offset += nread;

      const type = buffer.readUInt16BE(offset);

      const rr = {
        domain,
        cls: buffer.readUInt16BE(offset + 2),
      };
      offset += 4;

      for (const name in types) {
        if (types[name] === type)
          rr.type = name;
      }

      if (sectionName !== 'questions') {
        rr.ttl = buffer.readInt32BE(offset);
        const dataLength = buffer.readUInt16BE(offset);
        offset += 6;

        switch (type) {
          case types.A:
            assert.strictEqual(dataLength, 4);
            rr.address = `${buffer[offset + 0]}.${buffer[offset + 1]}.` +
                         `${buffer[offset + 2]}.${buffer[offset + 3]}`;
            break;
          case types.AAAA:
            assert.strictEqual(dataLength, 16);
            rr.address = buffer.toString('hex', offset, offset + 16)
                               .replace(/(.{4}(?!$))/g, '$1:');
            break;
          case types.TXT:
          {
            let position = offset;
            rr.entries = [];
            while (position < offset + dataLength) {
              const txtLength = buffer[offset];
              rr.entries.push(buffer.toString('utf8',