} // GetHostByName
// Does internal IPAddress reverse and then forward lookups (for Legacy and current public methods).
internal static IPHostEntry InternalGetHostByAddress(IPAddress address, bool includeIPv6)
{
if (GlobalLog.IsEnabled)
{
GlobalLog.Print("Dns.InternalGetHostByAddress: " + address.ToString());
}
//
// IPv6 Changes: We need to use the new getnameinfo / getaddrinfo functions
// for resolution of IPv6 addresses.
//
if (SocketProtocolSupportPal.OSSupportsIPv6 || includeIPv6)
{
//
// Try to get the data for the host from it's address
//
// We need to call getnameinfo first, because getaddrinfo w/ the ipaddress string
// will only return that address and not the full list.
// Do a reverse lookup to get the host name.
SocketError errorCode;
int nativeErrorCode;
string name = NameResolutionPal.TryGetNameInfo(address, out errorCode, out nativeErrorCode);
if (errorCode == SocketError.Success)
{
// Do the forward lookup to get the IPs for that host name
IPHostEntry hostEntry;
errorCode = NameResolutionPal.TryGetAddrInfo(name, out hostEntry, out nativeErrorCode);
if (errorCode == SocketError.Success)
{
return(hostEntry);
}
if (NetEventSource.Log.IsEnabled())
{
NetEventSource.Exception(NetEventSource.ComponentType.Socket, "DNS",
"InternalGetHostByAddress", new InternalSocketException(errorCode, nativeErrorCode));
}
// One of two things happened:
// 1. There was a ptr record in dns, but not a corollary A/AAA record.
// 2. The IP was a local (non-loopback) IP that resolved to a connection specific dns suffix.
// - Workaround, Check "Use this connection's dns suffix in dns registration" on that network
// adapter's advanced dns settings.
// Just return the resolved host name and no IPs.
return(hostEntry);
}
throw new InternalSocketException(errorCode, nativeErrorCode);
}
//
// If IPv6 is not enabled (maybe config switch) but we've been
// given an IPv6 address then we need to bail out now.
//
else
{
if (address.AddressFamily == AddressFamily.InterNetworkV6)
{
//
// Protocol not supported
//
throw new SocketException((int)SocketError.ProtocolNotSupported);
}
//
// Use gethostbyaddr() to try to resolve the IP address
//
// End IPv6 Changes
//
return(NameResolutionPal.GetHostByAddr(address));
}
} // InternalGetHostByAddress