private bool ValidateCommandNumbering(ISCSIPDU pdu, ConnectionState state)
{
if (state.Session == null)
{
return(true);
}
uint?cmdSN = PDUHelper.GetCmdSN(pdu);
Log(Severity.Verbose, "[{0}] Received PDU from initiator, Operation: {1}, Size: {2}, CmdSN: {3}", state.ConnectionIdentifier, (ISCSIOpCodeName)pdu.OpCode, pdu.Length, cmdSN);
// RFC 3720: On any connection, the iSCSI initiator MUST send the commands in increasing order of CmdSN,
// except for commands that are retransmitted due to digest error recovery and connection recovery.
if (cmdSN.HasValue)
{
if (state.Session.CommandNumberingStarted)
{
if (cmdSN != state.Session.ExpCmdSN)
{
return(false);
}
}
else
{
state.Session.ExpCmdSN = cmdSN.Value;
state.Session.CommandNumberingStarted = true;
}
if (pdu is LogoutRequestPDU || pdu is TextRequestPDU || pdu is SCSICommandPDU || pdu is RejectPDU)
{
if (!pdu.ImmediateDelivery)
{
state.Session.ExpCmdSN++;
}
}
}
return(true);
}
public void ProcessPDU(ISCSIPDU pdu, StateObject state)
{
Socket clientSocket = state.ClientSocket;
uint?cmdSN = PDUHelper.GetCmdSN(pdu);
Log(LogLevel.Debug, "[{0}][ProcessPDU] Received PDU from initiator, Operation: {1}, Size: {2}, CmdSN: {3}", state.ConnectionIdentifier, (ISCSIOpCodeName)pdu.OpCode, pdu.Length, cmdSN);
// RFC 3720: On any connection, the iSCSI initiator MUST send the commands in increasing order of CmdSN,
// except for commands that are retransmitted due to digest error recovery and connection recovery.
if (cmdSN.HasValue)
{
if (state.SessionParameters.CommandNumberingStarted)
{
if (cmdSN != state.SessionParameters.ExpCmdSN)
{
Log(LogLevel.Warning, "[{0}][ProcessPDU] CmdSN outside of expected range", state.ConnectionIdentifier);
// We ignore this PDU
return;
}
}
else
{
state.SessionParameters.ExpCmdSN = cmdSN.Value;
state.SessionParameters.CommandNumberingStarted = true;
}
if (pdu is LogoutRequestPDU || pdu is TextRequestPDU || pdu is SCSICommandPDU || pdu is RejectPDU)
{
if (!pdu.ImmediateDelivery)
{
state.SessionParameters.ExpCmdSN++;
}
}
}
if (pdu is LoginRequestPDU)
{
LoginRequestPDU request = (LoginRequestPDU)pdu;
Log(LogLevel.Information, "[{0}][ReceiveCallback] Login Request, current stage: {1}, next stage: {2}, parameters: {3}", state.ConnectionIdentifier, request.CurrentStage, request.NextStage, KeyValuePairUtils.ToString(request.LoginParameters));
if (request.TSIH != 0)
{
// RFC 3720: A Login Request with a non-zero TSIH and a CID equal to that of an existing
// connection implies a logout of the connection followed by a Login
lock (m_activeConnectionsLock)
{
int existingConnectionIndex = GetStateObjectIndex(m_activeConnections, request.ISID, request.TSIH, request.CID);
if (existingConnectionIndex >= 0)
{
// Perform implicit logout
Log(LogLevel.Information, "[{0}][ProcessPDU] Initiating implicit logout", state.ConnectionIdentifier);
SocketUtils.ReleaseSocket(m_activeConnections[existingConnectionIndex].ClientSocket);
if (m_activeConnections[existingConnectionIndex].Target != null)
{
lock (m_activeConnections[existingConnectionIndex].Target.IOLock)
{
// Wait for pending I/O to complete.
}
}
m_activeConnections.RemoveAt(existingConnectionIndex);
Log(LogLevel.Information, "[{0}][ProcessPDU] Implicit logout completed", state.ConnectionIdentifier);
}
}
}
LoginResponsePDU response = ServerResponseHelper.GetLoginResponsePDU(request, m_targets, state.SessionParameters, state.ConnectionParameters, ref state.Target, GetNextTSIH);
if (state.SessionParameters.IsFullFeaturePhase)
{
state.SessionParameters.ISID = request.ISID;
state.ConnectionParameters.CID = request.CID;
lock (m_activeConnectionsLock)
{
m_activeConnections.Add(state);
}
}
Log(LogLevel.Information, "[{0}][ReceiveCallback] Login Response parameters: {1}", state.ConnectionIdentifier, KeyValuePairUtils.ToString(response.LoginParameters));
TrySendPDU(state, response);
}
else if (!state.SessionParameters.IsFullFeaturePhase)
{
// Before the Full Feature Phase is established, only Login Request and Login Response PDUs are allowed.
Log(LogLevel.Warning, "[{0}][ProcessPDU] Improper command during login phase, OpCode: 0x{1}", state.ConnectionIdentifier, pdu.OpCode.ToString("x"));
// A target receiving any PDU except a Login request before the Login phase is started MUST
// immediately terminate the connection on which the PDU was received.
// Once the Login phase has started, if the target receives any PDU except a Login request,
// it MUST send a Login reject (with Status "invalid during login") and then disconnect.
clientSocket.Dispose();
}
else // Logged in
{
if (pdu is TextRequestPDU)
{
TextRequestPDU request = (TextRequestPDU)pdu;
TextResponsePDU response = ServerResponseHelper.GetTextResponsePDU(request, m_targets);
TrySendPDU(state, response);
}
else if (pdu is LogoutRequestPDU)
{
lock (m_activeConnectionsLock)
{
int connectionIndex = GetStateObjectIndex(m_activeConnections, state.SessionParameters.ISID, state.SessionParameters.TSIH, state.ConnectionParameters.CID);
if (connectionIndex >= 0)
{
if (m_activeConnections[connectionIndex].Target != null)
{
lock (m_activeConnections[connectionIndex].Target.IOLock)
{
// Wait for pending I/O to complete.
}
}
m_activeConnections.RemoveAt(connectionIndex);
}
}
LogoutRequestPDU request = (LogoutRequestPDU)pdu;
LogoutResponsePDU response = ServerResponseHelper.GetLogoutResponsePDU(request);
TrySendPDU(state, response);
clientSocket.Dispose(); // We can close the connection now
}
else if (state.SessionParameters.IsDiscovery)
{
// The target MUST ONLY accept text requests with the SendTargets key and a logout
// request with the reason "close the session". All other requests MUST be rejected.
Log(LogLevel.Warning, "[{0}][ProcessPDU] Improper command during discovery session, OpCode: 0x{1}", state.ConnectionIdentifier, pdu.OpCode.ToString("x"));
RejectPDU reject = new RejectPDU();
reject.Reason = RejectReason.ProtocolError;
reject.Data = ByteReader.ReadBytes(pdu.GetBytes(), 0, 48);
TrySendPDU(state, reject);
}
else if (pdu is NOPOutPDU)
{
NOPOutPDU request = (NOPOutPDU)pdu;
if (request.InitiatorTaskTag != 0xFFFFFFFF)
{
NOPInPDU response = ServerResponseHelper.GetNOPResponsePDU(request);
TrySendPDU(state, response);
}
}
else if (pdu is SCSIDataOutPDU)
{
// FIXME: the iSCSI target layer MUST deliver the commands for execution (to the SCSI execution engin) in the order specified by CmdSN
// e.g. read requests should not be executed while previous write request data is being received (via R2T)
SCSIDataOutPDU request = (SCSIDataOutPDU)pdu;
Log(LogLevel.Debug, "[{0}][ProcessPDU] SCSIDataOutPDU: Target transfer tag: {1}, LUN: {2}, Buffer offset: {3}, Data segment length: {4}, DataSN: {5}, Final: {6}", state.ConnectionIdentifier, request.TargetTransferTag, (ushort)request.LUN, request.BufferOffset, request.DataSegmentLength, request.DataSN, request.Final);
ISCSIPDU response = TargetResponseHelper.GetSCSIDataOutResponsePDU(request, state.Target, state.SessionParameters, state.ConnectionParameters);
TrySendPDU(state, response);
}
else if (pdu is SCSICommandPDU)
{
SCSICommandPDU command = (SCSICommandPDU)pdu;
Log(LogLevel.Debug, "[{0}][ProcessPDU] SCSICommandPDU: CmdSN: {1}, LUN: {2}, Data segment length: {3}, Expected Data Transfer Length: {4}, Final: {5}", state.ConnectionIdentifier, command.CmdSN, (ushort)command.LUN, command.DataSegmentLength, command.ExpectedDataTransferLength, command.Final);
List <ISCSIPDU> scsiResponseList = TargetResponseHelper.GetSCSIResponsePDU(command, state.Target, state.SessionParameters, state.ConnectionParameters);
foreach (ISCSIPDU response in scsiResponseList)
{
TrySendPDU(state, response);
if (!clientSocket.Connected)
{
return;
}
}
}
else
{
Log(LogLevel.Warning, "[{0}][ProcessPDU] Unsupported command, OpCode: 0x{1}", state.ConnectionIdentifier, pdu.OpCode.ToString("x"));
}
}
}