internal static DnsEntry Create(Linux.LDnsHeader head, Linux.LDnsReader reader)
{
switch (head.Type)
{
case (ushort)DnsRecordType.A:
case (ushort)DnsRecordType.AAAA:
return(new DnsHostEntry(head, reader));
case (ushort)DnsRecordType.NS:
case (ushort)DnsRecordType.PTR:
case (ushort)DnsRecordType.CNAME:
return(new DnsPointerEntry(head, reader));
case (ushort)DnsRecordType.MX:
return(new DnsMailExchangeEntry(head, reader));
case (ushort)DnsRecordType.SRV:
return(new DnsServiceEntry(head, reader));
case (ushort)DnsRecordType.TXT:
return(new DnsTextEntry(head, reader));
default:
//reader.Current += head.DataLen;
throw new NotSupportedException();
}
}
internal DnsEntry(Linux.LDnsHeader head)
{
Type = (DnsRecordType)head.Type;
Name = head.Name;
TimeToLive = TimeSpan.FromSeconds(head.TTL);
Expires = DateTime.UtcNow.Add(TimeToLive);
}
internal DnsServiceEntry(Linux.LDnsHeader head, Linux.LDnsReader reader) : base(head)
{
// Read Order Matters
Priority = reader.UInt16();
Weight = reader.UInt16();
Port = reader.UInt16();
Host = reader.Name();
}
internal DnsHostEntry(Linux.LDnsHeader head, Linux.LDnsReader reader) : base(head)
{
int byteCount = (Type == DnsRecordType.AAAA) ? 16 : 4;
byte[] addrBytes = reader.Bytes(byteCount);
Address = new IPAddress(addrBytes);
}
internal unsafe DnsTextEntry(Linux.LDnsHeader head, Linux.LDnsReader reader) : base(head)
{
var strings = new List <String>();
byte *pDataEnd = reader.Current + head.DataLen;
while (reader.Current < pDataEnd)
{
byte strLen = reader.Bytes(1)[0];
if (strLen > 0)
{
string s = reader.Text(strLen);
strings.Add(s);
}
}
Text = strings.ToArray();
}
public unsafe Task <DnsEntry[]> TryResolve()
{
var records = new List <DnsEntry>();
byte[] dataBuffer = new byte[1024];
int dataLen = LinuxLib.res_query(Query, C_IN, (int)Type, dataBuffer, dataBuffer.Length);
if (dataLen > 0)
{
GCHandle handle = GCHandle.Alloc(dataBuffer, GCHandleType.Pinned);
try
{
fixed(byte *pBuffer = dataBuffer)
{
var reader = new LDnsReader
{
Buffer = pBuffer,
Current = pBuffer,
End = pBuffer + dataLen
};
// Response Header
int queryId = reader.UInt16(); // Query Identifier (Read & Ignore)
byte[] hBits = reader.Bytes(2); // Header Bits & Flags (Read & Ignore)
int qdCount = reader.UInt16(); // Question Count (Use Below)
int anCount = reader.UInt16(); // Answer Count (Use Below)
int nsCount = reader.UInt16(); // NameServer Count (Read & Ignore)
int arCount = reader.UInt16(); // Resource Count (Read & Ignore)
// Question Section (read and ignore)
for (int q = 0; q < qdCount && reader.OK(); q++)
{
string qName = reader.Name();
ushort qType = reader.UInt16();
ushort qClass = reader.UInt16();
}
// Answers (the good stuff)
for (int a = 0; a < anCount && reader.OK(); a++)
{
var ansHead = new LDnsHeader(reader);
DnsEntry dnsEntry = DnsEntry.Create(ansHead, reader);
records.Add(dnsEntry);
}
}
}
finally
{
handle.Free();
}
}
_allRecords = records.ToArray();
_typeRecords = records.Where(r => r.Type == Type).ToArray();
if (Type == DnsRecordType.SRV || Type == DnsRecordType.MX) // sort
{
_typeRecords = _typeRecords.OrderBy(r => ((IOrderedDnsEntry)r).SortOrder).ToArray();
}
return(Task.FromResult(_typeRecords));
}
internal DnsPointerEntry(Linux.LDnsHeader head, Linux.LDnsReader reader) : base(head)
{
Target = reader.Name();
}
internal DnsMailExchangeEntry(Linux.LDnsHeader head, Linux.LDnsReader reader) : base(head)
{
// Read Order Matters
Preference = reader.UInt16();
Exchanger = reader.Name();
}