/// <summary>Constructor.</summary>
/// <remarks>
/// Sets internal ScopedPdu class to the argument supplied instance of the
/// class. This is a good cheat that will allow you direct access to the internal ScopedPdu class
/// since it is not cloned but assigned to the internal variable.
/// </remarks>
/// <param name="pdu"><see cref="ScopedPdu"/> class assigned to the class</param>
public SnmpV3Packet(ScopedPdu pdu)
: this()
{
if (pdu != null)
{
scopedPdu = pdu;
}
}
/// <summary>Constructor</summary>
/// <remarks>
/// Create new SNMPv3 packet class and initialize security parameters and ScopedPdu.
/// </remarks>
/// <param name="param">SNMPv3 security parameters</param>
/// <param name="pdu">ScopedPdu assigned to the class</param>
public SnmpV3Packet(SecureAgentParameters param, ScopedPdu pdu)
: this(param)
{
if (pdu != null)
{
scopedPdu = pdu;
}
}
/// <summary>
/// Standard constructor.
/// </summary>
public SnmpV3Packet()
: base(SnmpVersion.Ver3)
{
_messageId = new Integer32();
_maxMessageSize = new Integer32(64 * 1024);
_msgFlags = new MsgFlags();
_msgFlags.Reportable = true; // Make sure reportable is set to true by default
_securityModel = new Integer32();
_userSecurityModel = new UserSecurityModel();
_scopedPdu = new ScopedPdu();
}
/// <summary>Standard constructor.</summary>
public SnmpV3Packet()
: base(ESnmpVersion.Ver3)
{
messageId = new Integer32();
maxMessageSize = new Integer32(64 * 1024);
messageFlags = new MsgFlags
{
Reportable = true, // Make sure reportable is set to true by default
};
securityModel = new Integer32();
userSecurityModel = new UserSecurityModel();
scopedPdu = new ScopedPdu();
}
/// <summary>
/// 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.
/// </summary>
/// <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>
/// <param name="responseCallback">Callback that receives the result of the async operation.</param>
/// <returns>True if async request was successfully initiated, otherwise false.</returns>
public bool RequestAsync(Pdu pdu, IAgentParameters agentParameters, SnmpAsyncResponse responseCallback)
{
if (IsBusy)
{
return(false); // class is busy
}
_response = null;
_response += responseCallback;
_agentParameters = agentParameters;
byte[] outPacket;
if (agentParameters.Version == SnmpVersion.Ver3)
{
SecureAgentParameters secparams = (SecureAgentParameters)agentParameters;
if (secparams.Authentication != AuthenticationDigests.None && secparams.AuthenticationSecret.Length <= 0)
{
// _response(AsyncRequestResult.AuthenticationError, null);
return(false);
}
if (secparams.Privacy != PrivacyProtocols.None && secparams.PrivacySecret.Length <= 0)
{
// _response(AsyncRequestResult.PrivacyError, null);
return(false);
}
_noSourceCheck = false; // this option is not valid for SNMP v3 requests
ScopedPdu outPdu = new ScopedPdu(pdu);
outPdu.ContextEngineId.Set(secparams.EngineId);
outPdu.ContextName.Set(secparams.ContextName);
SnmpV3Packet packet = new SnmpV3Packet(outPdu);
secparams.InitializePacket(packet);
try
{
if (secparams.HasCachedKeys)
{
outPacket = packet.encode(secparams.AuthenticationKey, secparams.PrivacyKey);
}
else
{
outPacket = packet.encode();
}
}
catch (Exception ex)
{
ex.GetType();
_response(AsyncRequestResult.EncodeError, packet);
return(false);
}
}
else if (agentParameters.Version == (int)SnmpVersion.Ver1)
{
AgentParameters param = (AgentParameters)agentParameters;
_noSourceCheck = param.DisableReplySourceCheck;
SnmpV1Packet packet = new SnmpV1Packet();
packet.Pdu.Set(pdu);
packet.Community.Set(param.Community);
try
{
outPacket = packet.encode();
}
catch (Exception ex)
{
ex.GetType();
_response(AsyncRequestResult.EncodeError, packet);
return(false);
}
}
else if (agentParameters.Version == SnmpVersion.Ver2)
{
AgentParameters param = (AgentParameters)agentParameters;
_noSourceCheck = param.DisableReplySourceCheck;
SnmpV2Packet packet = new SnmpV2Packet();
packet.Pdu.Set(pdu);
packet.Community.Set(param.Community);
try
{
outPacket = packet.encode();
}
catch (Exception ex)
{
ex.GetType();
_response(AsyncRequestResult.EncodeError, packet);
return(false);
}
}
else
{
throw new SnmpInvalidVersionException("Unsupported SNMP version.");
}
if (!base.RequestAsync(_address, _port, outPacket, outPacket.Length, _timeout, _retry, new SnmpAsyncCallback(AsyncResponse)))
{
return(false);
}
return(true);
}
/// <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);
}
/// <summary>
/// Constructor.
/// </summary>
/// <remarks>
/// Sets internal ScopedPdu class to the argument supplied instance of the
/// class. This is a good cheat that will allow you direct access to the internal ScopedPdu class
/// since it is not cloned but assigned to the internal variable.
/// </remarks>
/// <param name="pdu"><see cref="ScopedPdu"/> class assigned to the class</param>
public SnmpV3Packet(ScopedPdu pdu)
: this()
{
if( pdu != null )
_scopedPdu = pdu;
}
/// <summary>
/// Constructor
/// </summary>
/// <remarks>
/// Create new SNMPv3 packet class and initialize security parameters and ScopedPdu.
/// </remarks>
/// <param name="param">SNMPv3 security parameters</param>
/// <param name="pdu">ScopedPdu assigned to the class</param>
public SnmpV3Packet(SecureAgentParameters param, ScopedPdu pdu)
: this(param)
{
if( pdu != null )
_scopedPdu = pdu;
}
/// <summary>
/// Standard constructor.
/// </summary>
public SnmpV3Packet()
: base(SnmpVersion.Ver3)
{
_messageId = new Integer32();
_maxMessageSize = new Integer32(64 * 1024);
_msgFlags = new MsgFlags();
_msgFlags.Reportable = true; // Make sure reportable is set to true by default
_securityModel = new Integer32();
_userSecurityModel = new UserSecurityModel();
_scopedPdu = new ScopedPdu();
}
/// <summary>
/// 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.
/// </summary>
/// <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>
/// <param name="responseCallback">Callback that receives the result of the async operation.</param>
/// <returns>True if async request was successfully initiated, otherwise false.</returns>
public bool RequestAsync(Pdu pdu, IAgentParameters agentParameters, SnmpAsyncResponse responseCallback)
{
if (IsBusy)
{
return false; // class is busy
}
_response = null;
_response += responseCallback;
_agentParameters = agentParameters;
byte[] outPacket;
if (agentParameters.Version == SnmpVersion.Ver3)
{
SecureAgentParameters secparams = (SecureAgentParameters)agentParameters;
if (secparams.Authentication != AuthenticationDigests.None && secparams.AuthenticationSecret.Length <= 0)
{
// _response(AsyncRequestResult.AuthenticationError, null);
return false;
}
if (secparams.Privacy != PrivacyProtocols.None && secparams.PrivacySecret.Length <= 0)
{
// _response(AsyncRequestResult.PrivacyError, null);
return false;
}
_noSourceCheck = false; // this option is not valid for SNMP v3 requests
ScopedPdu outPdu = new ScopedPdu(pdu);
outPdu.ContextEngineId.Set(secparams.EngineId);
outPdu.ContextName.Set(secparams.ContextName);
SnmpV3Packet packet = new SnmpV3Packet(outPdu);
secparams.InitializePacket(packet);
try
{
if (secparams.HasCachedKeys)
outPacket = packet.encode(secparams.AuthenticationKey, secparams.PrivacyKey);
else
outPacket = packet.encode();
}
catch( Exception ex )
{
ex.GetType();
_response(AsyncRequestResult.EncodeError, packet);
return false;
}
}
else if (agentParameters.Version == (int)SnmpVersion.Ver1)
{
AgentParameters param = (AgentParameters)agentParameters;
_noSourceCheck = param.DisableReplySourceCheck;
SnmpV1Packet packet = new SnmpV1Packet();
packet.Pdu.Set(pdu);
packet.Community.Set(param.Community);
try
{
outPacket = packet.encode();
}
catch( Exception ex)
{
ex.GetType();
_response(AsyncRequestResult.EncodeError, packet);
return false;
}
}
else if (agentParameters.Version == SnmpVersion.Ver2)
{
AgentParameters param = (AgentParameters)agentParameters;
_noSourceCheck = param.DisableReplySourceCheck;
SnmpV2Packet packet = new SnmpV2Packet();
packet.Pdu.Set(pdu);
packet.Community.Set(param.Community);
try
{
outPacket = packet.encode();
}
catch( Exception ex )
{
ex.GetType();
_response(AsyncRequestResult.EncodeError, packet);
return false;
}
}
else
{
throw new SnmpInvalidVersionException("Unsupported SNMP version.");
}
if( ! base.RequestAsync(_address, _port, outPacket, outPacket.Length, _timeout, _retry, new SnmpAsyncCallback(AsyncResponse) ) ) {
return false;
}
return true;
}
/// <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)
{
return null;
}
// 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;
}
/// <summary>
/// Encode SNMP version 3 packet
/// </summary>
/// <param name="authKey">Authentication key (not password)</param>
/// <param name="privKey">Privacy key (not password)</param>
/// <remarks>
/// Before encoding the packet into a byte array you need to ensure all required information is
/// set. Examples of required information is request type, Vbs (Oid + values pairs), USM settings including
/// SecretName, authentication method and secret (if needed), privacy method and secret (if needed), etc.
/// </remarks>
/// <returns>Byte array BER encoded SNMP packet.</returns>
public byte[] Encode(byte[] authKey, byte[] privKey)
{
MutableByte buffer = new MutableByte();
// encode the global message data sequence header information
MutableByte globalMessageData = new MutableByte();
// if message id is 0 then generate a new, random message id
if (_messageId.Value == 0)
{
Random rand = new Random();
_messageId.Value = rand.Next(1, Int32.MaxValue);
}
// encode message id
_messageId.Encode(globalMessageData);
// encode max message size
_maxMessageSize.Encode(globalMessageData);
// message flags
MsgFlags.Encode(globalMessageData);
// security model code
_securityModel.Value = USM.Type;
_securityModel.Encode(globalMessageData);
// add global message data to the main buffer
// encode sequence header and add data
AsnType.BuildHeader(buffer, SnmpConstants.SMI_SEQUENCE, globalMessageData.Length);
buffer.Append(globalMessageData);
MutableByte packetHeader = new MutableByte(buffer);
// before going down this road, check if this is a discovery packet
OctetString savedUserName = new OctetString();
bool privacy = MsgFlags.Privacy;
bool authentication = MsgFlags.Authentication;
bool reportable = MsgFlags.Reportable;
if (USM.EngineId.Length <= 0)
{
// save USM settings prior to encoding a Discovery packet
savedUserName.Set(USM.SecurityName);
USM.SecurityName.Reset(); // delete security name for discovery packets
MsgFlags.Authentication = false;
MsgFlags.Privacy = false;
MsgFlags.Reportable = true;
}
USM.Encode(buffer);
if (USM.EngineId.Length <= 0)
{
// restore saved USM values
USM.SecurityName.Set(savedUserName);
MsgFlags.Authentication = authentication;
MsgFlags.Privacy = privacy;
MsgFlags.Reportable = reportable;
}
// Check if privacy encryption is required
MutableByte encodedPdu = new MutableByte();
if (MsgFlags.Privacy && USM.EngineId.Length > 0)
{
IPrivacyProtocol privacyProtocol = PrivacyProtocol.GetInstance(USM.Privacy);
if (privacyProtocol == null)
{
throw new SnmpException(SnmpException.UnsupportedPrivacyProtocol, "Specified privacy protocol is not supported.");
}
// Get BER encoded ScopedPdu
MutableByte unencryptedPdu = new MutableByte();
ScopedPdu.Encode(unencryptedPdu);
// we have to expand the key
IAuthenticationDigest auth = Authentication.GetInstance(USM.Authentication);
if (auth == null)
{
throw new SnmpException(SnmpException.UnsupportedNoAuthPriv, "Invalid authentication protocol. noAuthPriv mode not supported.");
}
byte[] encryptedBuffer = privacyProtocol.Encrypt(unencryptedPdu, 0, unencryptedPdu.Length, privKey, USM.EngineBoots, USM.EngineTime, out byte[] privacyParameters, auth);
USM.PrivacyParameters.Set(privacyParameters);
OctetString encryptedOctetString = new OctetString(encryptedBuffer);
encryptedOctetString.Encode(encodedPdu);
// now redo packet encoding
buffer.Reset();
buffer.Set(packetHeader);
USM.Encode(buffer);
int preEncodedLength = encodedPdu.Length;
buffer.Append(encodedPdu);
if (_maxMessageSize.Value != 0)
{
// verify compliance with maximum message size
if ((encodedPdu.Length - preEncodedLength) > _maxMessageSize)
{
throw new SnmpException(SnmpException.MaximumMessageSizeExceeded, "ScopedPdu exceeds maximum message size.");
}
}
}
else
{
ScopedPdu.Encode(encodedPdu);
buffer.Append(encodedPdu);
}
base.Encode(buffer);
if (MsgFlags.Authentication && USM.EngineId.Length > 0)
{
USM.Authenticate(authKey, ref buffer);
// Now re-encode the packet with the authentication information
USM.Encode(packetHeader);
packetHeader.Append(encodedPdu);
base.Encode(packetHeader);
buffer = packetHeader;
}
return(buffer);
}
/// <summary>
/// Decode SNMP version 3 packet. This method will perform authentication check and decode privacy protected <see cref="ScopedPdu"/>. This method will
/// not check for the timeliness of the packet, correct engine boot value or engine id because it does not have a reference to the engine time prior to this call.
/// </summary>
/// <param name="berBuffer">BER encoded SNMP version 3 packet buffer</param>
/// <param name="length">Buffer length</param>
/// <param name="authKey">Authentication key (not password)</param>
/// <param name="privKey">Privacy key (not password)</param>
public int Decode(byte[] berBuffer, int length, byte[] authKey, byte[] privKey)
{
MutableByte buffer = new MutableByte(berBuffer, length);
int offset = 0;
// let base class parse first sequence and SNMP version number
offset = base.Decode(buffer, length);
// check for correct SNMP protocol version
if (_protocolVersion != (int)SnmpVersion.Ver3)
{
throw new SnmpInvalidVersionException("Expecting SNMP version 3.");
}
// now grab the global message data sequence header information
byte asnType = AsnType.ParseHeader(buffer, ref offset, out int len);
if (asnType != SnmpConstants.SMI_SEQUENCE)
{
throw new SnmpDecodingException("Invalid sequence type in global message data sequence.");
}
// check that packet size can accommodate the length specified in the header
if (len > (buffer.Length - offset))
{
throw new OverflowException("Packet is too small to contain the data described in the header.");
}
// retrieve message id
offset = _messageId.Decode(buffer, offset);
// max message size
offset = _maxMessageSize.Decode(buffer, offset);
// message flags
offset = MsgFlags.Decode(buffer, offset);
// verify that a valid authentication/privacy configuration is present in the packet
if (MsgFlags.Authentication == false && MsgFlags.Privacy == true)
{
throw new SnmpException(SnmpException.UnsupportedNoAuthPriv, "SNMP version 3 noAuthPriv security combination is not supported.");
}
// security model code
offset = _securityModel.Decode(buffer, offset);
// we only support USM. code = 0x03
if (_securityModel.Value != USM.Type)
{
throw new SnmpException(SnmpException.UnsupportedSecurityModel, "Class only support SNMP Version 3 User Security Model.");
}
// parse user security model
offset = USM.Decode(buffer, offset);
// Authenticate message if authentication flag is set and packet is not a discovery packet
if (MsgFlags.Authentication && USM.EngineId.Length > 0)
{
// Authenticate packet
if (USM.AuthenticationParameters.Length != 12)
{
throw new SnmpAuthenticationException("Invalid authentication parameter field length.");
}
if (!USM.IsAuthentic(authKey, buffer))
{
throw new SnmpAuthenticationException("Authentication of the incoming packet failed.");
}
}
// Decode ScopedPdu if it is privacy protected and packet is not a discovery packet
if (MsgFlags.Privacy && USM.EngineId.Length > 0)
{
IPrivacyProtocol privacyProtocol = PrivacyProtocol.GetInstance(USM.Privacy);
if (privacyProtocol == null)
{
throw new SnmpException(SnmpException.UnsupportedPrivacyProtocol, "Privacy protocol requested is not supported.");
}
if (USM.PrivacyParameters.Length != privacyProtocol.PrivacyParametersLength)
{
throw new SnmpException(SnmpException.InvalidPrivacyParameterLength, "Invalid privacy parameters field length.");
}
// Initialize a temporary OctetString class to hold encrypted ScopedPdu
OctetString encryptedScopedPdu = new OctetString();
offset = encryptedScopedPdu.Decode(buffer, offset);
// decode encrypted packet
byte[] decryptedScopedPdu = privacyProtocol.Decrypt(encryptedScopedPdu, 0, encryptedScopedPdu.Length, privKey, USM.EngineBoots, USM.EngineTime, USM.PrivacyParameters);
int tempOffset = 0;
offset = ScopedPdu.Decode(decryptedScopedPdu, tempOffset);
}
else
{
offset = ScopedPdu.Decode(buffer, offset);
}
return(offset);
}