/// <summary> /// Discovers agents of the specified version in a specific time interval. /// </summary> /// <param name="version">The version.</param> /// <param name="broadcastAddress">The broadcast address.</param> /// <param name="community">The community.</param> /// <param name="interval">The discovering time interval, in milliseconds.</param> /// <remarks><paramref name="broadcastAddress"/> must be an IPv4 address. IPv6 is not yet supported here.</remarks> public void Discover(VersionCode version, IPEndPoint broadcastAddress, OctetString community, int interval) { if (broadcastAddress == null) { throw new ArgumentNullException(nameof(broadcastAddress)); } if (version != VersionCode.V3 && community == null) { throw new ArgumentNullException(nameof(community)); } AddressFamily addressFamily = broadcastAddress.AddressFamily; if (addressFamily == AddressFamily.InterNetworkV6) { throw new ArgumentException("IP v6 is not yet supported.", nameof(broadcastAddress)); } byte[] bytes; _requestId = Messenger.NextRequestId; if (version == VersionCode.V3) { // throw new NotSupportedException("SNMP v3 is not supported"); Discovery discovery = new Discovery(Messenger.NextMessageId, _requestId, Messenger.MaxMessageSize); bytes = discovery.ToBytes(); } else { GetRequestMessage message = new GetRequestMessage(_requestId, version, community, _defaultVariables); bytes = message.ToBytes(); } using (UdpClient udp = new UdpClient(addressFamily)) { #if (!CF) udp.EnableBroadcast = true; #endif #if NET471 udp.Send(bytes, bytes.Length, broadcastAddress); #else AsyncHelper.RunSync(() => udp.SendAsync(bytes, bytes.Length, broadcastAddress)); #endif int activeBefore = Interlocked.CompareExchange(ref _active, Active, Inactive); if (activeBefore == Active) { // If already started, we've nothing to do. return; } _bufferSize = udp.Client.ReceiveBufferSize = Messenger.MaxMessageSize; #if ASYNC Task.Factory.StartNew(() => AsyncBeginReceive(udp.Client)); #else Task.Factory.StartNew(() => AsyncReceive(udp.Client)); #endif Thread.Sleep(interval); Interlocked.CompareExchange(ref _active, Inactive, Active); #if NET471 udp.Close(); #endif } }
/// <summary> /// Discovers agents of the specified version in a specific time interval. /// </summary> /// <param name="version">The version.</param> /// <param name="broadcastAddress">The broadcast address.</param> /// <param name="community">The community.</param> /// <param name="interval">The discovering time interval, in milliseconds.</param> /// <remarks><paramref name="broadcastAddress"/> must be an IPv4 address. IPv6 is not yet supported here.</remarks> public async Task DiscoverAsync(VersionCode version, IPEndPoint broadcastAddress, OctetString community, int interval) { if (broadcastAddress == null) { throw new ArgumentNullException(nameof(broadcastAddress)); } if (version != VersionCode.V3 && community == null) { throw new ArgumentNullException(nameof(community)); } AddressFamily addressFamily = broadcastAddress.AddressFamily; if (addressFamily == AddressFamily.InterNetworkV6) { throw new ArgumentException("IP v6 is not yet supported.", nameof(broadcastAddress)); } byte[] bytes; _requestId = Messenger.NextRequestId; if (version == VersionCode.V3) { // throw new NotSupportedException("SNMP v3 is not supported"); Discovery discovery = new Discovery(Messenger.NextMessageId, _requestId, Messenger.MaxMessageSize); bytes = discovery.ToBytes(); } else { GetRequestMessage message = new GetRequestMessage(_requestId, version, community, _defaultVariables); bytes = message.ToBytes(); } using (Socket udp = new Socket(addressFamily, SocketType.Dgram, ProtocolType.Udp)) { udp.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, true); SocketAsyncEventArgs info = SocketExtension.EventArgsFactory.Create(); info.RemoteEndPoint = broadcastAddress; info.SetBuffer(bytes, 0, bytes.Length); using (SocketAwaitable awaitable1 = new SocketAwaitable(info)) { await udp.SendToAsync(awaitable1); } int activeBefore = Interlocked.CompareExchange(ref _active, Active, Inactive); if (activeBefore == Active) { // If already started, we've nothing to do. return; } _bufferSize = udp.ReceiveBufferSize; await Task.WhenAny( ReceiveAsync(udp), Task.Delay(interval)); Interlocked.CompareExchange(ref _active, Inactive, Active); try { udp.Shutdown(SocketShutdown.Both); } catch (SocketException ex) { // This exception is thrown in .NET Core <=2.1.4 on non-Windows systems. // However, the shutdown call is necessary to release the socket binding. if (!SnmpMessageExtension.IsRunningOnWindows && ex.SocketErrorCode == SocketError.NotConnected) { } } } }