/// <summary>
/// Sends an <see cref="ISnmpMessage"/> and handles the response from agent.
/// </summary>
/// <param name="request">The <see cref="ISnmpMessage"/>.</param>
/// <param name="receiver">Agent.</param>
/// <param name="udpSocket">The UDP <see cref="Socket"/> to use to send/receive.</param>
/// <param name="registry">The user registry.</param>
/// <returns></returns>
public static async Task <ISnmpMessage> GetResponseAsync(this ISnmpMessage request, IPEndPoint receiver, UserRegistry registry, Socket udpSocket)
{
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
if (udpSocket == null)
{
throw new ArgumentNullException(nameof(udpSocket));
}
if (registry == null)
{
throw new ArgumentNullException(nameof(registry));
}
var requestCode = request.TypeCode();
if (requestCode == SnmpType.TrapV1Pdu || requestCode == SnmpType.TrapV2Pdu || requestCode == SnmpType.ReportPdu)
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, "not a request message: {0}", requestCode));
}
var bytes = request.ToBytes();
var bufSize = udpSocket.ReceiveBufferSize = Messenger.MaxMessageSize;
// Whatever you change, try to keep the Send and the Receive close to each other.
var info = SocketExtension.EventArgsFactory.Create();
info.RemoteEndPoint = receiver ?? throw new ArgumentNullException(nameof(receiver));
info.SetBuffer(bytes, 0, bytes.Length);
using (var awaitable1 = new SocketAwaitable(info))
{
await udpSocket.SendToAsync(awaitable1);
}
int count;
var reply = new byte[bufSize];
// IMPORTANT: follow http://blogs.msdn.com/b/pfxteam/archive/2011/12/15/10248293.aspx
var args = SocketExtension.EventArgsFactory.Create();
EndPoint remote = new IPEndPoint(IPAddress.Any, 0);
try
{
args.RemoteEndPoint = remote;
args.SetBuffer(reply, 0, bufSize);
using (var awaitable = new SocketAwaitable(args))
{
count = await udpSocket.ReceiveMessageFromAsync(awaitable);
}
}
catch (SocketException ex)
{
// IMPORTANT: Mono behavior (https://bugzilla.novell.com/show_bug.cgi?id=599488)
if (IsRunningOnMono && ex.SocketErrorCode == SocketError.WouldBlock)
{
throw TimeoutException.Create(receiver.Address, 0);
}
if (ex.SocketErrorCode == SocketError.TimedOut)
{
throw TimeoutException.Create(receiver.Address, 0);
}
throw;
}
// Passing 'count' is not necessary because ParseMessages should ignore it, but it offer extra safety (and would avoid an issue if parsing >1 response).
var response = MessageFactory.ParseMessages(reply, 0, count, registry)[0];
var responseCode = response.TypeCode();
if (responseCode == SnmpType.ResponsePdu || responseCode == SnmpType.ReportPdu)
{
var requestId = request.MessageId();
var responseId = response.MessageId();
if (responseId != requestId)
{
throw OperationException.Create(string.Format(CultureInfo.InvariantCulture, "wrong response sequence: expected {0}, received {1}", requestId, responseId), receiver.Address);
}
return(response);
}
throw OperationException.Create(string.Format(CultureInfo.InvariantCulture, "wrong response type: {0}", responseCode), receiver.Address);
}
/// <summary>
/// Sends an <see cref="ISnmpMessage"/> and handles the response from agent.
/// </summary>
/// <param name="request">The <see cref="ISnmpMessage"/>.</param>
/// <param name="timeout">The time-out value, in milliseconds. The default value is 0, which indicates an infinite time-out period. Specifying -1 also indicates an infinite time-out period.</param>
/// <param name="receiver">Agent.</param>
/// <param name="udpSocket">The UDP <see cref="Socket"/> to use to send/receive.</param>
/// <param name="registry">The user registry.</param>
/// <returns></returns>
public static ISnmpMessage GetResponse(this ISnmpMessage request, int timeout, IPEndPoint receiver, UserRegistry registry, Socket udpSocket)
{
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
if (udpSocket == null)
{
throw new ArgumentNullException(nameof(udpSocket));
}
if (receiver == null)
{
throw new ArgumentNullException(nameof(receiver));
}
if (registry == null)
{
throw new ArgumentNullException(nameof(registry));
}
var requestCode = request.TypeCode();
if (requestCode == SnmpType.TrapV1Pdu || requestCode == SnmpType.TrapV2Pdu || requestCode == SnmpType.ReportPdu)
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, "not a request message: {0}", requestCode));
}
var bytes = request.ToBytes();
var bufSize = udpSocket.ReceiveBufferSize = Messenger.MaxMessageSize;
var reply = new byte[bufSize];
// Whatever you change, try to keep the Send and the Receive close to each other.
udpSocket.SendTo(bytes, receiver);
udpSocket.ReceiveTimeout = timeout;
int count;
try
{
count = udpSocket.Receive(reply, 0, bufSize, SocketFlags.None);
}
catch (SocketException ex)
{
// IMPORTANT: Mono behavior.
if (IsRunningOnMono && ex.SocketErrorCode == SocketError.WouldBlock)
{
throw TimeoutException.Create(receiver.Address, timeout);
}
if (ex.SocketErrorCode == SocketError.TimedOut)
{
throw TimeoutException.Create(receiver.Address, timeout);
}
throw;
}
// Passing 'count' is not necessary because ParseMessages should ignore it, but it offer extra safety (and would avoid an issue if parsing >1 response).
var response = MessageFactory.ParseMessages(reply, 0, count, registry)[0];
var responseCode = response.TypeCode();
if (responseCode == SnmpType.ResponsePdu || responseCode == SnmpType.ReportPdu)
{
var requestId = request.MessageId();
var responseId = response.MessageId();
if (responseId != requestId)
{
throw OperationException.Create(string.Format(CultureInfo.InvariantCulture, "wrong response sequence: expected {0}, received {1}", requestId, responseId), receiver.Address);
}
return(response);
}
throw OperationException.Create(string.Format(CultureInfo.InvariantCulture, "wrong response type: {0}", responseCode), receiver.Address);
}