/// <summary>
/// Compares the current instance with another object of the same type.
/// </summary>
/// <param name="obj">An object to compare with this instance. </param>
/// <returns>Returns 0 if two objects are equal, returns negative value if this object is less,
/// returns positive value if this object is grater.</returns>
public int CompareTo(object obj)
{
if (obj == null)
{
throw new ArgumentNullException("obj");
}
if (!(obj is DnsRecord_MX))
{
throw new ArgumentException("Argument obj is not MX_Record !");
}
DnsRecord_MX mx = (DnsRecord_MX)obj;
if (this.Preference > mx.Preference)
{
return(1);
}
else if (this.Preference < mx.Preference)
{
return(-1);
}
else
{
return(0);
}
}
/// <summary>
/// Parses specified count of answers from query.
/// </summary>
/// <param name="reply">Server returned query.</param>
/// <param name="answerCount">Number of answers to parse.</param>
/// <param name="offset">Position from where to start parsing answers.</param>
/// <returns></returns>
private List <DnsRecord> ParseAnswers(byte[] reply, int answerCount, ref int offset)
{
/* RFC 1035 4.1.3. Resource record format
*
* 1 1 1 1 1 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |
| / /
| / NAME /
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TYPE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| CLASS |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TTL |
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| RDLENGTH |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
| / RDATA /
| / /
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*/
var answers = new List <DnsRecord>();
//---- Start parsing answers ------------------------------------------------------------------//
for (int i = 0; i < answerCount; i++)
{
string name = "";
if (!GetQName(reply, ref offset, ref name))
{
break;
}
int type = reply[offset++] << 8 | reply[offset++];
int rdClass = reply[offset++] << 8 | reply[offset++];
int ttl = reply[offset++] << 24 | reply[offset++] << 16 | reply[offset++] << 8 | reply[offset++];
int rdLength = reply[offset++] << 8 | reply[offset++];
var _type = (DnsRecordType)type;
if (_type == DnsRecordType.A)
{
answers.Add(DnsRecord_A.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.AAAA)
{
answers.Add(DnsRecord_AAAA.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.NS)
{
answers.Add(DnsRecord_NS.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.CNAME)
{
answers.Add(DnsRecord_CNAME.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.MX)
{
answers.Add(DnsRecord_MX.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.TXT)
{
answers.Add(DnsRecord_TXT.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.SOA)
{
answers.Add(DnsRecord_SOA.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.PTR)
{
answers.Add(DnsRecord_PTR.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.HINFO)
{
answers.Add(DnsRecord_HINFO.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.SRV)
{
answers.Add(DnsRecord_SRV.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.NAPTR)
{
answers.Add(DnsRecord_NAPTR.Parse(name, reply, ref offset, rdLength, ttl));
}
else if (_type == DnsRecordType.SPF)
{
answers.Add(DnsRecord_SPF.Parse(name, reply, ref offset, rdLength, ttl));
}
else
{
// Unknown record, skip it.
offset += rdLength;
}
}
return(answers);
}