private static unsafe void GetAddressInfoExCallback([In] int error, [In] int bytes, [In] NativeOverlapped *overlapped)
{
// Can be casted directly to GetAddrInfoExContext* because the overlapped is its first field
GetAddrInfoExContext *context = (GetAddrInfoExContext *)overlapped;
ProcessResult((SocketError)error, context);
}
public static unsafe void GetAddrInfoAsync(DnsResolveAsyncResult asyncResult)
{
GetAddrInfoExContext *context = GetAddrInfoExContext.AllocateContext();
try
{
var state = new GetAddrInfoExState(asyncResult);
context->QueryStateHandle = state.CreateHandle();
}
catch
{
GetAddrInfoExContext.FreeContext(context);
throw;
}
AddressInfoEx hints = new AddressInfoEx();
hints.ai_flags = AddressInfoHints.AI_CANONNAME;
hints.ai_family = AddressFamily.Unspecified; // Gets all address families
SocketError errorCode =
(SocketError)Interop.Winsock.GetAddrInfoExW(asyncResult.HostName, null, 0 /* NS_ALL*/, IntPtr.Zero, ref hints, out context->Result, IntPtr.Zero, ref context->Overlapped, s_getAddrInfoExCallback, out context->CancelHandle);
if (errorCode != SocketError.IOPending)
{
ProcessResult(errorCode, context);
}
}
public static void FreeContext(GetAddrInfoExContext *context)
{
if (context->Result != null)
{
Interop.Winsock.FreeAddrInfoExW(context->Result);
}
Marshal.FreeHGlobal((IntPtr)context);
}
public CancellationToken UnregisterAndGetCancellationToken()
{
lock (this)
{
_cancellationContext = null;
_cancellationRegistration.Unregister();
}
return(_cancellationRegistration.Token);
}
public GetAddrInfoExState(GetAddrInfoExContext *context, string hostName, bool justAddresses)
{
_cancellationContext = context;
HostName = hostName;
JustAddresses = justAddresses;
if (justAddresses)
{
IPAddressArrayBuilder = AsyncTaskMethodBuilder <IPAddress[]> .Create();
_ = IPAddressArrayBuilder.Task; // force initialization
}
else
{
IPHostEntryBuilder = AsyncTaskMethodBuilder <IPHostEntry> .Create();
_ = IPHostEntryBuilder.Task; // force initialization
}
}
public void RegisterForCancellation(CancellationToken cancellationToken)
{
if (!cancellationToken.CanBeCanceled)
{
return;
}
lock (this)
{
if (_cancellationContext == null)
{
// The operation completed before registration could be done.
return;
}
_cancellationRegistration = cancellationToken.UnsafeRegister(o =>
{
var @this = (GetAddrInfoExState)o !;
int cancelResult = 0;
lock (@this)
{
GetAddrInfoExContext *context = @this._cancellationContext;
if (context != null)
{
// An outstanding operation will be completed with WSA_E_CANCELLED, and GetAddrInfoExCancel will return NO_ERROR.
// If this thread has lost the race between cancellation and completion, this will be a NOP
// with GetAddrInfoExCancel returning WSA_INVALID_HANDLE.
cancelResult = Interop.Winsock.GetAddrInfoExCancel(&context->CancelHandle);
}
}
if (cancelResult != 0 && cancelResult != Interop.Winsock.WSA_INVALID_HANDLE && NetEventSource.Log.IsEnabled())
{
NetEventSource.Info(@this, $"GetAddrInfoExCancel returned error {cancelResult}");
}
}, this);
}
}
public GetAddrInfoExState(string hostName, bool justAddresses)
: base(true)
{
HostName = hostName;
JustAddresses = justAddresses;
if (justAddresses)
{
IPAddressArrayBuilder = AsyncTaskMethodBuilder <IPAddress[]> .Create();
_ = IPAddressArrayBuilder.Task; // force initialization
}
else
{
IPHostEntryBuilder = AsyncTaskMethodBuilder <IPHostEntry> .Create();
_ = IPHostEntryBuilder.Task; // force initialization
}
GetAddrInfoExContext *context = GetAddrInfoExContext.AllocateContext();
context->QueryStateHandle = CreateHandle();
SetHandle((IntPtr)context);
}
private static unsafe void ProcessResult(SocketError errorCode, GetAddrInfoExContext *context)
{
try
{
GetAddrInfoExState state = GetAddrInfoExState.FromHandleAndFree(context->QueryStateHandle);
if (errorCode != SocketError.Success)
{
state.CompleteAsyncResult(new SocketException((int)errorCode));
return;
}
AddressInfoEx *result = context->Result;
string canonicalName = null;
List <IPAddress> addresses = new List <IPAddress>();
while (result != null)
{
if (canonicalName == null && result->ai_canonname != IntPtr.Zero)
{
canonicalName = Marshal.PtrToStringUni(result->ai_canonname);
}
var socketAddress = new ReadOnlySpan <byte>(result->ai_addr, result->ai_addrlen);
if (result->ai_family == AddressFamily.InterNetwork)
{
if (socketAddress.Length == SocketAddressPal.IPv4AddressSize)
{
addresses.Add(CreateIPv4Address(socketAddress));
}
}
else if (SocketProtocolSupportPal.OSSupportsIPv6 && result->ai_family == AddressFamily.InterNetworkV6)
{
if (socketAddress.Length == SocketAddressPal.IPv6AddressSize)
{
addresses.Add(CreateIPv6Address(socketAddress));
}
}
result = result->ai_next;
}
if (canonicalName == null)
{
canonicalName = state.HostName;
}
state.CompleteAsyncResult(new IPHostEntry
{
HostName = canonicalName,
Aliases = Array.Empty <string>(),
AddressList = addresses.ToArray()
});
}
finally
{
GetAddrInfoExContext.FreeContext(context);
}
}
