public static string[] GetTXTRecord(string domain)
{
IntPtr ptr1 = IntPtr.Zero;
IntPtr ptr2 = IntPtr.Zero;
PDNS_TXT_RECORD DnsAnswer;
if (Environment.OSVersion.Platform != PlatformID.Win32NT)
{
throw new NotSupportedException();
}
ArrayList list1 = new ArrayList();
int num1 = DnsapiQuery.DnsQuery(ref domain, QueryTypes.DNS_TYPE_TXT, QueryOptions.DNS_QUERY_BYPASS_CACHE, 0, ref ptr1, 0);
if (num1 != 0)
{
throw new Win32Exception(num1);
}
for (ptr2 = ptr1; !ptr2.Equals(IntPtr.Zero); ptr2 = DnsAnswer.pNext)
{
DnsAnswer = (PDNS_TXT_RECORD)Marshal.PtrToStructure(ptr2, typeof(PDNS_TXT_RECORD));
QueryTypes recType = (QueryTypes)DnsAnswer.wType;
if (recType == QueryTypes.DNS_TYPE_TXT)
{
string Result = Marshal.PtrToStringAuto(DnsAnswer.pStringArray);
list1.Add(Result);
}
}
DnsapiQuery.DnsRecordListFree(ptr1, 0);
return((string[])list1.ToArray(typeof(string)));
}
// http://www.team-cymru.org/Services/ip-to-asn.html#dns
/// <summary>
/// Given an IP address, finds the origin AS number as advertised in BGP. Uses cymru.com DNS services to map IP to ASN.
/// </summary>
/// <param name="Address">IP address</param>
/// <returns>Bar-delimited field showing AS number, component prefix, countrry of origin, and date of ASN registration with RIR</returns>
public object FindASN(string Address)
{
IPAddress _addr;
if (!IPAddress.TryParse(Address, out _addr))
{
return(new ErrorWrapper((int)CVErrNum.ErrValue));
}
if (_addr.AddressFamily != AddressFamily.InterNetwork && _addr.AddressFamily != AddressFamily.InterNetworkV6)
{
return(new ErrorWrapper((int)CVErrNum.ErrValue));
}
StringBuilder sb = new StringBuilder();
List <string> AddrBytesStrings = new List <string>();
byte[] AddrBytes = _addr.GetAddressBytes();
bool FoundNonZeroValue = false;
for (int i = AddrBytes.Length - 1; i >= 0; i--)
{
if (AddrBytes[i] > 0 || (AddrBytes[i] == 0 && FoundNonZeroValue == true))
{
FoundNonZeroValue = true;
if (_addr.AddressFamily == AddressFamily.InterNetworkV6)
{
AddrBytesStrings.Add(String.Format("{0:x1}", AddrBytes[i] % 0x10));
AddrBytesStrings.Add(String.Format("{0:x1}", AddrBytes[i] / 0x10));
}
else
{
AddrBytesStrings.Add(String.Format("{0}", AddrBytes[i]));
}
}
}
sb.Append(String.Join(".", AddrBytesStrings));
if (_addr.AddressFamily == AddressFamily.InterNetworkV6)
{
sb.Append(".origin6.asn.cymru.com");
}
else
{
sb.Append(".origin.asn.cymru.com");
}
string[] output;
try
{
output = DnsapiQuery.GetTXTRecord(sb.ToString());
}
catch (Win32Exception e)
{
return(e.Message);
}
return(output[0]);
}
