[NetworkInformation] Support network IP/status events

	Add support for the events in NetworkChanged (linux-only).

configure.in

@@ -368,6 +368,10 @@ AM_CONDITIONAL(NO_VERSION_SCRIPT, test x$no_version_script = xyes)
 
 AC_CHECK_HEADERS(sys/filio.h sys/sockio.h netdb.h utime.h sys/utime.h semaphore.h sys/un.h linux/rtc.h sys/syscall.h sys/mkdev.h sys/uio.h sys/param.h)
 AC_CHECK_HEADERS(sys/param.h sys/socket.h sys/ipc.h sys/sem.h sys/utsname.h alloca.h ucontext.h pwd.h sys/select.h netinet/tcp.h netinet/in.h unistd.h sys/types.h link.h asm/sigcontext.h)
+AC_CHECK_HEADERS([linux/netlink.h linux/rtnetlink.h],
+                  [], [], [#include <stddef.h>
+		  #include <sys/socket.h>
+		  #include <linux/socket.h>])
 
 AC_CHECK_HEADERS(sys/user.h, [], [],
 [

mcs/class/System/System.Net.NetworkInformation/NetworkChange.cs

@@ -4,7 +4,7 @@
 // Author:
 //	Gonzalo Paniagua Javier (gonzalo@novell.com)
 //
-// Copyright (c) 2006 Novell, Inc. (http://www.novell.com)
+// Copyright (c) 2006,2011 Novell, Inc. (http://www.novell.com)
 //
 // Permission is hereby granted, free of charge, to any person obtaining
 // a copy of this software and associated documentation files (the
@@ -25,19 +25,177 @@
 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
-#if NET_2_0
+
+using System.Net.Sockets;
+using System.Runtime.InteropServices;
+using System.Threading;
+
 namespace System.Net.NetworkInformation {
 	public sealed class NetworkChange {
+		[Flags]
+		enum EventType {
+			Availability = 1 << 0,
+			Address = 1 << 1,
+		}
+
+		static object _lock = new object ();
+		static Socket nl_sock;
+		static SocketAsyncEventArgs nl_args;
+		static EventType pending_events;
+		static Timer timer;
+
+		static NetworkAddressChangedEventHandler AddressChanged;
+		static NetworkAvailabilityChangedEventHandler AvailabilityChanged;
+
 		private NetworkChange ()
 		{
 		}
 
-		// Disable the warnings about the events not being used.
-#pragma warning disable 67
-		public static event NetworkAddressChangedEventHandler NetworkAddressChanged;
-		public static event NetworkAvailabilityChangedEventHandler NetworkAvailabilityChanged;
-#pragma warning restore
+		public static event NetworkAddressChangedEventHandler NetworkAddressChanged {
+			add { Register (value); }
+			remove { Unregister (value); }
+		}
+
+		public static event NetworkAvailabilityChangedEventHandler NetworkAvailabilityChanged {
+			add { Register (value); }
+			remove { Unregister (value); }
+		}
+
+		//internal Socket (AddressFamily family, SocketType type, ProtocolType proto, IntPtr sock)
+
+		static bool EnsureSocket ()
+		{
+			lock (_lock) {
+				if (nl_sock != null)
+					return true;
+				IntPtr fd = CreateNLSocket ();
+				if (fd.ToInt64 () == -1)
+					return false;
+
+				nl_sock = new Socket (0, SocketType.Raw, ProtocolType.Udp, fd);
+				nl_args = new SocketAsyncEventArgs ();
+				nl_args.SetBuffer (new byte [8192], 0, 8192);
+				nl_args.Completed += OnDataAvailable;
+				nl_sock.ReceiveAsync (nl_args);
+			}
+			return true;
+		}
+
+		// _lock is held by the caller
+		static void MaybeCloseSocket ()
+		{
+			if (nl_sock == null || AvailabilityChanged != null || AddressChanged != null)
+				return;
+
+			CloseNLSocket (nl_sock.Handle);
+			GC.SuppressFinalize (nl_sock);
+			nl_sock = null;
+			nl_args = null;
+		}
+
+		static bool GetAvailability ()
+		{
+			NetworkInterface [] adapters = NetworkInterface.GetAllNetworkInterfaces ();
+			foreach (NetworkInterface n in adapters) {
+				// TODO: also check for a default route present?
+				if (n.NetworkInterfaceType == NetworkInterfaceType.Loopback)
+					continue;
+				if (n.OperationalStatus == OperationalStatus.Up)
+					return true;
+			}
+			return false;
+		}
+
+		static void OnAvailabilityChanged (object unused)
+		{
+			NetworkAvailabilityChangedEventHandler d = AvailabilityChanged;
+			d (null, new NetworkAvailabilityEventArgs (GetAvailability ()));
+		}
+
+		static void OnAddressChanged (object unused)
+		{
+			NetworkAddressChangedEventHandler d = AddressChanged;
+			d (null, EventArgs.Empty);
+		}
+
+		static void OnEventDue (object unused)
+		{
+			EventType evts;
+			lock (_lock) {
+				evts = pending_events;
+				pending_events = 0;
+				timer.Change (-1, -1);
+			}
+			if ((evts & EventType.Availability) != 0)
+				ThreadPool.QueueUserWorkItem (OnAvailabilityChanged);
+			if ((evts & EventType.Address) != 0)
+				ThreadPool.QueueUserWorkItem (OnAddressChanged);
+		}
+
+		static void QueueEvent (EventType type)
+		{
+			lock (_lock) {
+				if (timer == null)
+					timer = new Timer (OnEventDue);
+				if (pending_events == 0)
+					timer.Change (150, -1);
+				pending_events |= type;
+			}
+		}
+
+		unsafe static void OnDataAvailable (object sender, SocketAsyncEventArgs args)
+		{
+			EventType type;
+			fixed (byte *ptr = args.Buffer) {	
+				type = ReadEvents (nl_sock.Handle, new IntPtr (ptr), args.BytesTransferred, 8192);
+			}
+			nl_sock.ReceiveAsync (nl_args);
+			if (type != 0)
+				QueueEvent (type);
+		}
+
+		static void Register (NetworkAddressChangedEventHandler d)
+		{
+			EnsureSocket ();
+			AddressChanged += d;
+		}
+
+		static void Register (NetworkAvailabilityChangedEventHandler d)
+		{
+			EnsureSocket ();
+			AvailabilityChanged += d;
+		}
+
+		static void Unregister (NetworkAddressChangedEventHandler d)
+		{
+			lock (_lock) {
+				AddressChanged -= d;
+				MaybeCloseSocket ();
+			}
+		}
+
+		static void Unregister (NetworkAvailabilityChangedEventHandler d)
+		{
+			lock (_lock) {
+				AvailabilityChanged -= d;
+				MaybeCloseSocket ();
+			}
+		}
+
+#if MONOTOUCH || MONODROID
+		const string LIBNAME = "__Internal";
+#else
+		const string LIBNAME = "MonoPosixHelper";
+#endif
+
+		[DllImport (LIBNAME, CallingConvention=CallingConvention.Cdecl)]
+		static extern IntPtr CreateNLSocket ();
+
+		[DllImport (LIBNAME, CallingConvention=CallingConvention.Cdecl)]
+		static extern EventType ReadEvents (IntPtr sock, IntPtr buffer, int count, int size);
+
+		[DllImport (LIBNAME, CallingConvention=CallingConvention.Cdecl)]
+		static extern IntPtr CloseNLSocket (IntPtr sock);
 	}
 }
-#endif
 

mcs/class/System/System.Net.NetworkInformation/NetworkInterface.cs

@@ -52,7 +52,6 @@ protected NetworkInterface ()
 		{
 		}
 
-		[MonoTODO("Only works on Linux and Windows")]
 		public static NetworkInterface [] GetAllNetworkInterfaces ()
 		{
 			if (runningOnUnix) {

support/Makefile.am

@@ -32,6 +32,8 @@ MPH_UNIX_SOURCE =				\
 	fstab.c					\
 	grp.c					\
 	macros.c				\
+	nl.c					\
+	nl.h					\
 	old-map.c				\
 	old-map.h				\
 	pwd.c					\