/// <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("request");
}
if (udpSocket == null)
{
throw new ArgumentNullException("udpSocket");
}
if (receiver == null)
{
throw new ArgumentNullException("receiver");
}
if (registry == null)
{
throw new ArgumentNullException("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();
#if CF
int bufSize = 8192;
#else
var bufSize = udpSocket.ReceiveBufferSize;
#endif
var reply = new byte[bufSize];
// Whatever you change, try to keep the Send and the Receive close to each other.
udpSocket.SendTo(bytes, receiver);
int count;
// IMPORTANT: follow http://blogs.msdn.com/b/pfxteam/archive/2011/12/15/10248293.aspx
var args = new SocketAsyncEventArgs();
try
{
args.SetBuffer(reply, 0, bufSize);
var awaitable = new SocketAwaitable(args);
count = await SocketExtensions.ReceiveAsync(udpSocket, awaitable);
}
catch (SocketException ex)
{
// FIXME: If you use a Mono build without the fix for this issue (https://bugzilla.novell.com/show_bug.cgi?id=599488), please uncomment this code.
/*
* if (SnmpMessageExtension.IsRunningOnMono && ex.ErrorCode == 10035)
* {
* throw TimeoutException.Create(receiver.Address, timeout);
* }
* // */
if (ex.SocketErrorCode == SocketError.TimedOut)
{
throw TimeoutException.Create(receiver.Address, 0);
}
throw;
}
finally
{
args.Dispose();
}
// 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);
}
