public DnsResponseMessage GetResponseMessage(ArraySegment <byte> responseData)
{
var reader = new DnsDatagramReader(responseData);
var id = reader.ReadUInt16NetworkOrder();
var flags = reader.ReadUInt16NetworkOrder();
var questionCount = reader.ReadUInt16NetworkOrder();
var answerCount = reader.ReadUInt16NetworkOrder();
var nameServerCount = reader.ReadUInt16NetworkOrder();
var additionalCount = reader.ReadUInt16NetworkOrder();
var header = new DnsResponseHeader(id, flags, questionCount, answerCount, additionalCount, nameServerCount);
var response = new DnsResponseMessage(header, responseData.Count);
for (var questionIndex = 0; questionIndex < questionCount; questionIndex++)
{
var questionQueryString = reader.ReadQuestionQueryString();
var queryTypeValue = reader.ReadUInt16NetworkOrder();
var queryClass = reader.ReadUInt16NetworkOrder();
if (!_queryTypes.TryGetValue(queryTypeValue, out var queryType))
{
queryType = new PseudoResourceRecordType(
abbreviation: "Unknown",
value: queryTypeValue
);
}
var question = new DnsQuestion(questionQueryString, queryType, (QueryClass)queryClass);
response.AddQuestion(question);
}
for (var answerIndex = 0; answerIndex < answerCount; answerIndex++)
{
var info = ReadRecordInfo(reader);
var record = _dnsRecordFactory.GetRecord(info, reader);
response.AddAnswer(record);
}
for (var serverIndex = 0; serverIndex < nameServerCount; serverIndex++)
{
var info = ReadRecordInfo(reader);
var record = _dnsRecordFactory.GetRecord(info, reader);
response.AddAuthority(record);
}
for (var additionalIndex = 0; additionalIndex < additionalCount; additionalIndex++)
{
var info = ReadRecordInfo(reader);
var record = _dnsRecordFactory.GetRecord(info, reader);
response.AddAdditional(record);
}
return(response);
}
/// <summary>
/// Reads a <see cref="ResourceRecord"/> from this <see cref="DnsDatagramReader"/>.
/// </summary>
private ResourceRecord ReadRecordInfo(DnsDatagramReader reader)
{
var queryString = reader.ReadQuestionQueryString();
var type = reader.ReadUInt16NetworkOrder();
if (!_resourceRecordTypes.TryGetValue(type, out var resourceRecordType))
{
resourceRecordType = new PseudoResourceRecordType(
abbreviation: "Unknown - machine generated",
value: type
);
}
var queryClass = reader.ReadUInt16NetworkOrder();
var ttl = reader.ReadUInt32NetworkOrder();
var rdLength = reader.ReadUInt16NetworkOrder();
return(new ResourceRecord(
queryString, // name
resourceRecordType, // type
(QueryClass)queryClass, // class
(int)ttl, // ttl - 32bit!!
rdLength)); // RDLength
}
/// <summary>
/// Initializes a new instance of the <see cref="DnsQuestion"/> class.
/// </summary>
/// <param name="query">The query.</param>
/// <param name="questionType">Type of the question.</param>
/// <param name="questionClass">The question class.</param>
/// <exception cref="ArgumentNullException">If <paramref name="query"/> is null.</exception>
public DnsQuestion(DnsString query, PseudoResourceRecordType questionType, QueryClass questionClass)
{
QueryName = query ?? throw new ArgumentNullException(nameof(query));
QuestionType = questionType;
QuestionClass = questionClass;
}
/// <summary>
/// Initializes a new instance of the <see cref="DnsQuestion"/> class.
/// </summary>
/// <param name="query">The query.</param>
/// <param name="questionType">Type of the question.</param>
/// <param name="questionClass">The question class.</param>
/// <exception cref="ArgumentNullException">If <paramref name="query"/> is null.</exception>
public DnsQuestion(string query, PseudoResourceRecordType questionType, QueryClass questionClass)
: this(DnsString.Parse(query), questionType, questionClass)
{
}
private void Add(PseudoResourceRecordType type) => _dictionary[type.Value] = type;
/// <summary>
/// Filters the elements of an <see cref="IEnumerable{T}"/> to return <see cref="DnsResourceRecord"/>s
/// which have the <paramref name="type"/>.
/// </summary>
/// <param name="records">The records.</param>
/// <param name="type">The <see cref="PseudoResourceRecordType"/> to filter for.</param>
/// <returns>The list of <see cref="ARecord"/>.</returns>
public static IEnumerable <DnsResourceRecord> OfRecordType(this IEnumerable <DnsResourceRecord> records, PseudoResourceRecordType type)
{
return(records.Where(p => p.RecordType == type));
}
