// For names -> type A Query
// For IP addresses -> PTR + A -> will at least return itself
// Careful: for IP addresses with PTR, the hostname might yield different IP addresses!
public bool GetHostEntryAsync (SimpleResolverEventArgs args)
{
if (args == null)
throw new ArgumentNullException ("args");
if (args.HostName == null)
throw new ArgumentNullException ("args.HostName is null");
if (args.HostName.Length > 255)
throw new ArgumentException ("args.HostName is too long");
args.Reset (ResolverAsyncOperation.GetHostEntry);
string host = args.HostName;
if (host == "") {
GetLocalHost (args);
return false;
}
IPAddress addr;
if (IPAddress.TryParse (host, out addr)) {
IPHostEntry entry = new IPHostEntry ();
entry.HostName = host;
entry.Aliases = EmptyStrings;
entry.AddressList = new IPAddress [1] { addr };
args.HostEntry = entry;
args.PTRAddress = addr;
SendPTRQuery (args, true);
return true;
}
// 3. For IP addresses:
// 3.1 Parsing IP succeeds
// 3.2 Reverse lookup of the IP fills in HostName -> fails? HostName = IP
// 3.3 The hostname resulting from this is used to query DNS again to get the IP addresses
//
// Exclude IPv6 addresses if not supported by the system
// .Aliases is always empty
// Length > 255
SendAQuery (args, true);
return true;
}
// Type A query
// Might fill in Aliases
// -IPAddress -> return the same IPAddress
// -"" -> Local host ip addresses (filter out IPv6 if needed)
public bool GetHostAddressesAsync (SimpleResolverEventArgs args)
{
if (args == null)
throw new ArgumentNullException ("args");
if (args.HostName == null)
throw new ArgumentNullException ("args.HostName is null");
if (args.HostName.Length > 255)
throw new ArgumentException ("args.HostName is too long");
args.Reset (ResolverAsyncOperation.GetHostAddresses);
string host = args.HostName;
if (host == "") {
GetLocalHost (args);
return false;
}
IPAddress addr;
if (IPAddress.TryParse (host, out addr)) {
IPHostEntry entry = new IPHostEntry ();
entry.HostName = host;
entry.Aliases = EmptyStrings;
entry.AddressList = new IPAddress [1] { addr };
args.HostEntry = entry;
return false;
}
SendAQuery (args, true);
return true;
}