|
public ValidateIncomingPacket ( |
||
| packet | Received and parsed SNMP version 3 packet. | |
| return | bool | |
internal void AsyncResponse(AsyncRequestResult result, IPEndPoint peer, byte[] buffer, int buflen)
{
if (result != AsyncRequestResult.NoError)
{
_response(result, null);
}
else
{
if (buffer == null || buffer.Length <= 0 || buflen <= 0)
{
_response(AsyncRequestResult.NoDataReceived, null);
return;
}
// verify packet
if (_agentParameters.Version == (int)SnmpVersion.Ver1)
{
SnmpV1Packet packet = new SnmpV1Packet();
try
{
packet.decode(buffer, buflen);
}
catch (Exception ex)
{
ex.GetType();
// Console.WriteLine("Exception while decoding SNMP packet: " + ex.ToString());
_response(AsyncRequestResult.DecodeError, packet);
return;
}
_response(AsyncRequestResult.NoError, packet);
return;
}
else if (_agentParameters.Version == SnmpVersion.Ver2)
{
SnmpV2Packet packet = new SnmpV2Packet();
try
{
packet.decode(buffer, buflen);
}
catch (Exception ex)
{
ex.GetType();
// Console.WriteLine("Exception while decoding SNMP packet: " + ex.ToString());
// MutableByte b = new MutableByte(buffer, buflen);
// Console.WriteLine("Buffer length {0}", buflen);
// SnmpConstants.DumpHex(b);
_response(AsyncRequestResult.DecodeError, packet);
return;
}
_response(AsyncRequestResult.NoError, packet);
}
else if (_agentParameters.Version == SnmpVersion.Ver3)
{
SnmpV3Packet packet = new SnmpV3Packet();
SecureAgentParameters secparams = (SecureAgentParameters)_agentParameters;
secparams.InitializePacket(packet);
try {
if (secparams.HasCachedKeys)
{
packet.decode(buffer, buflen, secparams.AuthenticationKey, secparams.PrivacyKey);
}
else
{
packet.decode(buffer, buflen);
}
}
catch
{
_response(AsyncRequestResult.DecodeError, packet);
return;
}
if (!secparams.ValidateIncomingPacket(packet))
{
_response(AsyncRequestResult.AuthenticationError, packet);
}
else
{
secparams.UpdateDiscoveryValues(packet); // update time, etc. values
_response(AsyncRequestResult.NoError, packet);
}
}
}
}
/// <summary>Make SNMP Request</summary>
/// <remarks>
/// Make SNMP request. With this method you can make blocked SNMP version 1, 2 and 3 requests of type GET,
/// GET-NEXT, GET-BULK, SET and REPORT (request types have to compatible with the SNMP protocol version you
/// are using).
///
/// This method will pass through any exceptions thrown by parsing classes/methods so see individual packet
/// classes, ASN.1 type classes, authentication, privacy, etc. classes for exceptions thrown.
/// </remarks>
/// <param name="pdu">Pdu class (do not pass ScopedPdu)</param>
/// <param name="agentParameters">Security information for the request. Use <see cref="AgentParameters"/>
/// for SNMP versions 1 and 2 requests. Use <see cref="SecureAgentParameters"/> for SNMP version 3
/// requests.</param>
/// <returns>Appropriate SNMP packet class for the reply received (<see cref="SnmpV1Packet"/>,
/// <see cref="SnmpV2Packet"/>, or <see cref="SnmpV3Packet"/>. Null value if there was an error
/// with the request.</returns>
/// <exception cref="SnmpAuthenticationException">Thrown on SNMPv3 requests when authentication password
/// is not specified on authNoPriv or authPriv requests in SecureAgentParameters or if incoming packet
/// authentication check failed.
///
/// With SNMP ver1 and ver2c, authentication check fails when invalid community name is parsed in the reply.</exception>
/// <exception cref="SnmpPrivacyException">Thrown on SNMPv3 requests when privacy password is not
/// specified in SecureAgentParameters on authPriv requests.</exception>
/// <exception cref="SnmpException">Thrown in following cases:
///
/// * IAgentParameters.Valid() returned false. SnmpException.ErrorCode is set to SnmpException.InvalidIAgentParameters
/// * No data received on request. SnmpException.ErrorCode is set to SnmpException.NoDataReceived
/// * Invalid RequestId in reply. SnmpException.ErrorCode is set to SnmpException.InvalidRequestId
/// </exception>
public SnmpPacket Request(Pdu pdu, IAgentParameters agentParameters)
{
byte[] outPacket;
if (agentParameters.Version == SnmpVersion.Ver3)
{
SecureAgentParameters secparams = (SecureAgentParameters)agentParameters;
if (secparams.Authentication != AuthenticationDigests.None && secparams.AuthenticationSecret.Length <= 0)
{
throw new SnmpAuthenticationException("Authentication password not specified.");
}
if (secparams.Privacy != PrivacyProtocols.None && secparams.PrivacySecret.Length <= 0)
{
throw new SnmpPrivacyException("Privacy password not specified.");
}
_noSourceCheck = false; // this option is not valid for SNMP v3 requests
ScopedPdu outPdu = new ScopedPdu(pdu);
SnmpV3Packet packet = new SnmpV3Packet(outPdu);
secparams.InitializePacket(packet);
if (secparams.HasCachedKeys)
{
outPacket = packet.encode(secparams.AuthenticationKey, secparams.PrivacyKey);
}
else
{
outPacket = packet.encode();
}
}
else if (agentParameters.Version == SnmpVersion.Ver1)
{
AgentParameters param = (AgentParameters)agentParameters;
if (!param.Valid())
{
throw new SnmpException(SnmpException.InvalidIAgentParameters, "Invalid AgentParameters. Unable to process request.");
}
SnmpV1Packet packet = new SnmpV1Packet();
packet.Pdu.Set(pdu);
packet.Community.Set(param.Community);
outPacket = packet.encode();
_noSourceCheck = param.DisableReplySourceCheck;
}
else if (agentParameters.Version == SnmpVersion.Ver2)
{
AgentParameters param = (AgentParameters)agentParameters;
if (!param.Valid())
{
throw new SnmpException(SnmpException.InvalidIAgentParameters, "Invalid AgentParameters. Unable to process request.");
}
SnmpV2Packet packet = new SnmpV2Packet();
packet.Pdu.Set(pdu);
packet.Community.Set(param.Community);
_noSourceCheck = param.DisableReplySourceCheck;
outPacket = packet.encode();
}
else
{
throw new SnmpInvalidVersionException("Unsupported SNMP version.");
}
byte[] inBuffer = base.Request(_address, _port, outPacket, outPacket.Length, _timeout, _retry);
if (inBuffer == null || inBuffer.Length <= 0)
{
throw new SnmpException(SnmpException.NoDataReceived, "No data received on request.");
}
// verify packet
if (agentParameters.Version == SnmpVersion.Ver1)
{
SnmpV1Packet packet = new SnmpV1Packet();
AgentParameters param = (AgentParameters)agentParameters;
packet.decode(inBuffer, inBuffer.Length);
if (packet.Community != param.Community)
{
// invalid community name received. Ignore the rest of the packet
throw new SnmpAuthenticationException("Invalid community name in reply.");
}
if (packet.Pdu.RequestId != pdu.RequestId)
{
// invalid request id. unmatched response ignored
throw new SnmpException(SnmpException.InvalidRequestId, "Invalid request id in reply.");
}
return(packet);
}
else if (agentParameters.Version == SnmpVersion.Ver2)
{
SnmpV2Packet packet = new SnmpV2Packet();
AgentParameters param = (AgentParameters)agentParameters;
packet.decode(inBuffer, inBuffer.Length);
if (packet.Community != param.Community)
{
// invalid community name received. Ignore the rest of the packet
throw new SnmpAuthenticationException("Invalid community name in reply.");
}
if (packet.Pdu.RequestId != pdu.RequestId)
{
// invalid request id. unmatched response ignored
throw new SnmpException(SnmpException.InvalidRequestId, "Invalid request id in reply.");
}
return(packet);
}
else if (agentParameters.Version == SnmpVersion.Ver3)
{
SnmpV3Packet packet = new SnmpV3Packet();
SecureAgentParameters secparams = (SecureAgentParameters)agentParameters;
secparams.InitializePacket(packet);
if (secparams.HasCachedKeys)
{
packet.decode(inBuffer, inBuffer.Length, secparams.AuthenticationKey, secparams.PrivacyKey);
}
else
{
packet.decode(inBuffer, inBuffer.Length);
}
// first check if packet is a discovery response and process it
if (packet.Pdu.Type == PduType.Report && packet.Pdu.VbCount > 0 && packet.Pdu.VbList[0].Oid.Equals(SnmpConstants.usmStatsUnknownEngineIDs))
{
secparams.UpdateDiscoveryValues(packet);
return(packet);
}
else
{
if (!secparams.ValidateIncomingPacket(packet))
{
return(null);
}
else
{
secparams.UpdateDiscoveryValues(packet); // update time, etc. values
return(packet);
}
}
}
return(null);
}