Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Net / System / Net / NetworkInformation / NetworkAddressChange.cs / 1 / NetworkAddressChange.cs
namespace System.Net.NetworkInformation { using System.Net; using System.Net.NetworkInformation; using System.Net.Sockets; using System.Collections; using System.Collections.Specialized; using System.ComponentModel; using System.Threading; using System.Runtime.InteropServices; [Flags] internal enum StartIPOptions {Both = 3, None = 0, StartIPv4 = 1, StartIPv6 = 2} public class NetworkAvailabilityEventArgs:EventArgs{ bool isAvailable; internal NetworkAvailabilityEventArgs(bool isAvailable){ this.isAvailable = isAvailable; } public bool IsAvailable{ get{ return isAvailable; } } } public sealed class NetworkChange{ private NetworkChange(){} static public event NetworkAvailabilityChangedEventHandler NetworkAvailabilityChanged{ add{ if (! ComNetOS.IsWin2K) throw new PlatformNotSupportedException(SR.GetString(SR.Win2000Required)); AvailabilityChangeListener.Start(value); } remove{ AvailabilityChangeListener.Stop(value); } } static public event NetworkAddressChangedEventHandler NetworkAddressChanged{ add{ if (! ComNetOS.IsWin2K) throw new PlatformNotSupportedException(SR.GetString(SR.Win2000Required)); AddressChangeListener.Start(value); } remove{ AddressChangeListener.Stop(value); } } static internal bool CanListenForNetworkChanges { get{ if (! ComNetOS.IsWin2K ) return false; return true; } } /* Consider removing static internal void UnsafeListenForNetworkChanges(NetworkAddressChangedEventHandler handler) { if (!CanListenForNetworkChanges) { throw new PlatformNotSupportedException(SR.GetString(SR.Win2000Required)); } AddressChangeListener.UnsafeStart(handler); } */ internal static class AvailabilityChangeListener{ static object syncObject = new object(); static private ListDictionary s_availabilityCallerArray = null; static NetworkAddressChangedEventHandler addressChange = null; static bool isAvailable = false; private static ContextCallback s_RunHandlerCallback = new ContextCallback(RunHandlerCallback); private static void RunHandlerCallback(object state) { ((NetworkAvailabilityChangedEventHandler) state)(null, new NetworkAvailabilityEventArgs(isAvailable)); } private static void ChangedAddress(object sender, EventArgs eventArgs) { lock(syncObject){ bool isAvailableNow = SystemNetworkInterface.InternalGetIsNetworkAvailable(); if (isAvailableNow != isAvailable) { isAvailable = isAvailableNow; DictionaryEntry[] callerArray = new DictionaryEntry[s_availabilityCallerArray.Count]; s_availabilityCallerArray.CopyTo(callerArray, 0); for (int i = 0; i < callerArray.Length; i++) { NetworkAvailabilityChangedEventHandler handler = (NetworkAvailabilityChangedEventHandler) callerArray[i].Key; ExecutionContext context = (ExecutionContext) callerArray[i].Value; if (context == null) { handler(null, new NetworkAvailabilityEventArgs(isAvailable)); } else { ExecutionContext.Run(context.CreateCopy(), s_RunHandlerCallback, handler); } } } } } internal static void Start(NetworkAvailabilityChangedEventHandler caller){ lock(syncObject){ if (s_availabilityCallerArray == null) { s_availabilityCallerArray = new ListDictionary(); addressChange = new NetworkAddressChangedEventHandler(ChangedAddress); } if (s_availabilityCallerArray.Count == 0) { isAvailable = NetworkInterface.GetIsNetworkAvailable(); AddressChangeListener.UnsafeStart(addressChange); } if ((caller != null) && (!s_availabilityCallerArray.Contains(caller))) { s_availabilityCallerArray.Add(caller, ExecutionContext.Capture()); } } } internal static void Stop(NetworkAvailabilityChangedEventHandler caller) { lock(syncObject){ s_availabilityCallerArray.Remove(caller); if(s_availabilityCallerArray.Count == 0){ AddressChangeListener.Stop(addressChange); } } } } //helper class for detecting address change events. internal unsafe static class AddressChangeListener{ static private ListDictionary s_callerArray = new ListDictionary(); static private ContextCallback s_runHandlerCallback = new ContextCallback(RunHandlerCallback); static private RegisteredWaitHandle s_registeredWait; //need to keep the reference so it isn't GC'd before the native call executes static private bool s_isListening = false; static private bool s_isPending = false; static private SafeCloseSocketAndEvent s_ipv4Socket = null; static private SafeCloseSocketAndEvent s_ipv6Socket = null; static private WaitHandle s_ipv4WaitHandle = null; static private WaitHandle s_ipv6WaitHandle = null; //callback fired when an address change occurs private static void AddressChangedCallback(object stateObject, bool signaled) { lock (s_callerArray) { //the listener was cancelled, which would only happen if we aren't listening //for more events. s_isPending = false; if (!s_isListening) { return; } s_isListening = false; // Need to copy the array so the callback can call start and stop DictionaryEntry[] callerArray = new DictionaryEntry[s_callerArray.Count]; s_callerArray.CopyTo(callerArray, 0); //wait for the next address change StartHelper(null,false,(StartIPOptions)stateObject); for (int i = 0; i < callerArray.Length; i++) { NetworkAddressChangedEventHandler handler = (NetworkAddressChangedEventHandler) callerArray[i].Key; ExecutionContext context = (ExecutionContext) callerArray[i].Value; if (context == null) { handler(null, EventArgs.Empty); } else { ExecutionContext.Run(context.CreateCopy(), s_runHandlerCallback, handler); } } } } private static void RunHandlerCallback(object state) { ((NetworkAddressChangedEventHandler) state)(null, EventArgs.Empty); } //start listening internal static void Start(NetworkAddressChangedEventHandler caller) { StartHelper(caller, true, StartIPOptions.Both); } internal static void UnsafeStart(NetworkAddressChangedEventHandler caller) { StartHelper(caller, false, StartIPOptions.Both); } private static void StartHelper(NetworkAddressChangedEventHandler caller, bool captureContext, StartIPOptions startIPOptions) { lock (s_callerArray) { // setup changedEvent and native overlapped struct. if(s_ipv4Socket == null){ Socket.InitializeSockets(); int blocking; if(Socket.SupportsIPv4){ blocking = -1; s_ipv4Socket = SafeCloseSocketAndEvent.CreateWSASocketWithEvent(AddressFamily.InterNetwork, SocketType.Dgram, (ProtocolType)0, true, false); UnsafeNclNativeMethods.OSSOCK.ioctlsocket(s_ipv4Socket, IoctlSocketConstants.FIONBIO,ref blocking); s_ipv4WaitHandle = s_ipv4Socket.GetEventHandle(); } if(Socket.OSSupportsIPv6){ blocking = -1; s_ipv6Socket = SafeCloseSocketAndEvent.CreateWSASocketWithEvent(AddressFamily.InterNetworkV6, SocketType.Dgram, (ProtocolType)0, true, false); UnsafeNclNativeMethods.OSSOCK.ioctlsocket(s_ipv6Socket,IoctlSocketConstants.FIONBIO,ref blocking); s_ipv6WaitHandle = s_ipv6Socket.GetEventHandle(); } } if ((caller != null) && (!s_callerArray.Contains(caller))) { s_callerArray.Add(caller, captureContext ? ExecutionContext.Capture() : null); } //if s_listener is not null, it means we are already actively listening if (s_isListening || s_callerArray.Count == 0) { return; } if(!s_isPending){ int length; SocketError errorCode; if(Socket.SupportsIPv4 && (startIPOptions & StartIPOptions.StartIPv4) !=0){ s_registeredWait = ThreadPool.UnsafeRegisterWaitForSingleObject( s_ipv4WaitHandle, new WaitOrTimerCallback(AddressChangedCallback), StartIPOptions.StartIPv4, -1, true ); errorCode = (SocketError) UnsafeNclNativeMethods.OSSOCK.WSAIoctl_Blocking( s_ipv4Socket.DangerousGetHandle(), (int) IOControlCode.AddressListChange, null, 0, null, 0, out length, IntPtr.Zero, IntPtr.Zero); if (errorCode != SocketError.Success) { NetworkInformationException exception = new NetworkInformationException(); if (exception.ErrorCode != (uint)SocketError.WouldBlock) { throw exception; } } errorCode = (SocketError)UnsafeNclNativeMethods.OSSOCK.WSAEventSelect(s_ipv4Socket, s_ipv4Socket.GetEventHandle().SafeWaitHandle, AsyncEventBits.FdAddressListChange); if (errorCode != SocketError.Success) { throw new NetworkInformationException(); } } if(Socket.OSSupportsIPv6 && (startIPOptions & StartIPOptions.StartIPv6) !=0){ s_registeredWait = ThreadPool.UnsafeRegisterWaitForSingleObject( s_ipv6WaitHandle, new WaitOrTimerCallback(AddressChangedCallback), StartIPOptions.StartIPv6, -1, true ); errorCode = (SocketError) UnsafeNclNativeMethods.OSSOCK.WSAIoctl_Blocking( s_ipv6Socket.DangerousGetHandle(), (int) IOControlCode.AddressListChange, null, 0, null, 0, out length, IntPtr.Zero, IntPtr.Zero); if (errorCode != SocketError.Success) { NetworkInformationException exception = new NetworkInformationException(); if (exception.ErrorCode != (uint)SocketError.WouldBlock) { throw exception; } } errorCode = (SocketError)UnsafeNclNativeMethods.OSSOCK.WSAEventSelect(s_ipv6Socket, s_ipv6Socket.GetEventHandle().SafeWaitHandle, AsyncEventBits.FdAddressListChange); if (errorCode != SocketError.Success) { throw new NetworkInformationException(); } } } s_isListening = true; s_isPending = true; } } //stop listening internal static void Stop(object caller) { lock(s_callerArray){ s_callerArray.Remove(caller); if (s_callerArray.Count == 0 && s_isListening) { s_isListening = false; } } } //ends ignoreaddresschanges } } public delegate void NetworkAddressChangedEventHandler(object sender, EventArgs e); public delegate void NetworkAvailabilityChangedEventHandler(object sender, NetworkAvailabilityEventArgs e); }
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