|
public static GetHostByName ( string hostName ) : |
||
| hostName | string | |
| return | ||
private static IPHostEntry InternalGetHostByName(string hostName, bool includeIPv6)
{
if (NetEventSource.Log.IsEnabled())
{
NetEventSource.Enter(NetEventSource.ComponentType.Socket, "DNS", "GetHostByName", hostName);
}
IPHostEntry ipHostEntry = null;
if (GlobalLog.IsEnabled)
{
GlobalLog.Print("Dns.GetHostByName: " + hostName);
}
if (hostName.Length > MaxHostName || // If 255 chars, the last one must be a dot.
hostName.Length == MaxHostName && hostName[MaxHostName - 1] != '.')
{
throw new ArgumentOutOfRangeException(nameof(hostName), SR.Format(SR.net_toolong,
nameof(hostName), MaxHostName.ToString(NumberFormatInfo.CurrentInfo)));
}
//
// IPv6 Changes: IPv6 requires the use of getaddrinfo() rather
// than the traditional IPv4 gethostbyaddr() / gethostbyname().
// getaddrinfo() is also protocol independent in that it will also
// resolve IPv4 names / addresses. As a result, it is the preferred
// resolution mechanism on platforms that support it (Windows 5.1+).
// If getaddrinfo() is unsupported, IPv6 resolution does not work.
//
// Consider : If IPv6 is disabled, we could detect IPv6 addresses
// and throw an unsupported platform exception.
//
// Note : Whilst getaddrinfo is available on WinXP+, we only
// use it if IPv6 is enabled (platform is part of that
// decision). This is done to minimize the number of
// possible tests that are needed.
//
if (includeIPv6 || SocketProtocolSupportPal.OSSupportsIPv6)
{
//
// IPv6 enabled: use getaddrinfo() to obtain DNS information.
//
int nativeErrorCode;
SocketError errorCode = NameResolutionPal.TryGetAddrInfo(hostName, out ipHostEntry, out nativeErrorCode);
if (errorCode != SocketError.Success)
{
throw SocketExceptionFactory.CreateSocketException(errorCode, nativeErrorCode);
}
}
else
{
ipHostEntry = NameResolutionPal.GetHostByName(hostName);
}
if (NetEventSource.Log.IsEnabled())
{
NetEventSource.Exit(NetEventSource.ComponentType.Socket, "DNS", "GetHostByName", ipHostEntry);
}
return(ipHostEntry);
} // GetHostByName
private static IPHostEntry InternalGetHostByName(string hostName, bool includeIPv6)
{
if (NetEventSource.IsEnabled)
{
NetEventSource.Enter(null, hostName);
}
IPHostEntry ipHostEntry = null;
ValidateHostName(hostName);
//
// IPv6 Changes: IPv6 requires the use of getaddrinfo() rather
// than the traditional IPv4 gethostbyaddr() / gethostbyname().
// getaddrinfo() is also protocol independent in that it will also
// resolve IPv4 names / addresses. As a result, it is the preferred
// resolution mechanism on platforms that support it (Windows 5.1+).
// If getaddrinfo() is unsupported, IPv6 resolution does not work.
//
// Consider : If IPv6 is disabled, we could detect IPv6 addresses
// and throw an unsupported platform exception.
//
// Note : Whilst getaddrinfo is available on WinXP+, we only
// use it if IPv6 is enabled (platform is part of that
// decision). This is done to minimize the number of
// possible tests that are needed.
//
if (includeIPv6 || SocketProtocolSupportPal.OSSupportsIPv6)
{
//
// IPv6 enabled: use getaddrinfo() to obtain DNS information.
//
int nativeErrorCode;
SocketError errorCode = NameResolutionPal.TryGetAddrInfo(hostName, out ipHostEntry, out nativeErrorCode);
if (errorCode != SocketError.Success)
{
throw SocketExceptionFactory.CreateSocketException(errorCode, nativeErrorCode);
}
}
else
{
ipHostEntry = NameResolutionPal.GetHostByName(hostName);
}
if (NetEventSource.IsEnabled)
{
NetEventSource.Exit(null, ipHostEntry);
}
return(ipHostEntry);
} // GetHostByName