internal static void Stop(NetworkAddressChangedEventHandler?caller)
{
if (caller != null)
{
lock (s_globalLock)
{
s_addressChangedSubscribers.Remove(caller);
if (s_addressChangedSubscribers.Count == 0 && s_isListening)
{
s_isListening = false;
}
}
}
}
private static void StartHelper(NetworkAddressChangedEventHandler?caller, bool captureContext, StartIPOptions startIPOptions)
{
lock (s_globalLock)
{
// Setup changedEvent and native overlapped struct.
if (s_ipv4Socket == null)
{
// Sockets will be initialized by the call to OSSupportsIP*.
if (Socket.OSSupportsIPv4)
{
s_ipv4Socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, 0)
{
Blocking = false
};
s_ipv4WaitHandle = new AutoResetEvent(false);
}
if (Socket.OSSupportsIPv6)
{
s_ipv6Socket = new Socket(AddressFamily.InterNetworkV6, SocketType.Dgram, 0)
{
Blocking = false
};
s_ipv6WaitHandle = new AutoResetEvent(false);
}
}
if (caller != null)
{
s_addressChangedSubscribers.TryAdd(caller, captureContext ? ExecutionContext.Capture() : null);
}
if (s_isListening || s_addressChangedSubscribers.Count == 0)
{
return;
}
if (!s_isPending)
{
if (Socket.OSSupportsIPv4 && (startIPOptions & StartIPOptions.StartIPv4) != 0)
{
ThreadPool.RegisterWaitForSingleObject(
s_ipv4WaitHandle !,
new WaitOrTimerCallback(AddressChangedCallback),
StartIPOptions.StartIPv4,
-1,
true);
SocketError errorCode = Interop.Winsock.WSAIoctl_Blocking(
s_ipv4Socket !.SafeHandle,
(int)IOControlCode.AddressListChange,
null, 0, null, 0,
out int length,
IntPtr.Zero, IntPtr.Zero);
if (errorCode != SocketError.Success)
{
NetworkInformationException exception = new NetworkInformationException();
if (exception.ErrorCode != (uint)SocketError.WouldBlock)
{
throw exception;
}
}
errorCode = Interop.Winsock.WSAEventSelect(
s_ipv4Socket.SafeHandle,
s_ipv4WaitHandle !.GetSafeWaitHandle(),
Interop.Winsock.AsyncEventBits.FdAddressListChange);
if (errorCode != SocketError.Success)
{
throw new NetworkInformationException();
}
}
if (Socket.OSSupportsIPv6 && (startIPOptions & StartIPOptions.StartIPv6) != 0)
{
ThreadPool.RegisterWaitForSingleObject(
s_ipv6WaitHandle !,
new WaitOrTimerCallback(AddressChangedCallback),
StartIPOptions.StartIPv6,
-1,
true);
SocketError errorCode = Interop.Winsock.WSAIoctl_Blocking(
s_ipv6Socket !.SafeHandle,
(int)IOControlCode.AddressListChange,
null, 0, null, 0,
out int length,
IntPtr.Zero, IntPtr.Zero);
if (errorCode != SocketError.Success)
{
NetworkInformationException exception = new NetworkInformationException();
if (exception.ErrorCode != (uint)SocketError.WouldBlock)
{
throw exception;
}
}
errorCode = Interop.Winsock.WSAEventSelect(
s_ipv6Socket.SafeHandle,
s_ipv6WaitHandle !.GetSafeWaitHandle(),
Interop.Winsock.AsyncEventBits.FdAddressListChange);
if (errorCode != SocketError.Success)
{
throw new NetworkInformationException();
}
}
}
s_isListening = true;
s_isPending = true;
}
}
internal static void UnsafeStart(NetworkAddressChangedEventHandler?caller)
{
StartHelper(caller, false, StartIPOptions.Both);
}