internal static List <ReadyToTransferPDU> GetReadyToTransferPDUs(SCSICommandPDU command, ConnectionParameters connection, out List <SCSICommandPDU> commandsToExecute)
{
// We return either SCSIResponsePDU or List<SCSIDataInPDU>
List <ReadyToTransferPDU> responseList = new List <ReadyToTransferPDU>();
commandsToExecute = new List <SCSICommandPDU>();
ISCSISession session = connection.Session;
if (command.Write && command.DataSegmentLength < command.ExpectedDataTransferLength)
{
uint transferTag = session.GetNextTransferTag();
// Create buffer for next segments (we only execute the command after receiving all of its data)
Array.Resize <byte>(ref command.Data, (int)command.ExpectedDataTransferLength);
// Send R2Ts:
uint bytesLeft = command.ExpectedDataTransferLength - command.DataSegmentLength;
uint nextOffset = command.DataSegmentLength;
if (!session.InitialR2T)
{
uint firstDataPDULength = Math.Min((uint)session.FirstBurstLength, command.ExpectedDataTransferLength) - command.DataSegmentLength;
bytesLeft -= firstDataPDULength;
nextOffset += firstDataPDULength;
}
int totalR2Ts = (int)Math.Ceiling((double)bytesLeft / connection.TargetMaxRecvDataSegmentLength);
int outgoingR2Ts = Math.Min(session.MaxOutstandingR2T, totalR2Ts);
for (uint index = 0; index < outgoingR2Ts; index++)
{
ReadyToTransferPDU response = new ReadyToTransferPDU();
response.InitiatorTaskTag = command.InitiatorTaskTag;
response.R2TSN = index; // R2Ts are sequenced per command and must start with 0 for each new command;
response.TargetTransferTag = transferTag;
response.BufferOffset = nextOffset;
response.DesiredDataTransferLength = Math.Min((uint)connection.TargetMaxRecvDataSegmentLength, command.ExpectedDataTransferLength - response.BufferOffset);
responseList.Add(response);
nextOffset += (uint)connection.TargetMaxRecvDataSegmentLength;
}
connection.AddTransfer(transferTag, command, (uint)outgoingR2Ts, nextOffset, (uint)totalR2Ts);
session.CommandsInTransfer.Add(command.CmdSN);
return(responseList);
}
if (session.IsPrecedingCommandPending(command.CmdSN))
{
session.DelayedCommands.Add(command);
}
else
{
commandsToExecute.Add(command);
}
return(responseList);
}
internal static ISCSIPDU GetSCSIDataOutResponsePDU(SCSIDataOutPDU request, ISCSITarget target, SessionParameters session, ConnectionParameters connection)
{
string connectionIdentifier = StateObject.GetConnectionIdentifier(session, connection);
TransferEntry transfer = connection.GetTransferEntry(request.TargetTransferTag);
if (transfer == null)
{
ISCSIServer.Log("[{0}][GetSCSIDataOutResponsePDU] Invalid TargetTransferTag {1}", connectionIdentifier, request.TargetTransferTag);
RejectPDU reject = new RejectPDU();
reject.InitiatorTaskTag = request.InitiatorTaskTag;
reject.Reason = RejectReason.InvalidPDUField;
reject.Data = ByteReader.ReadBytes(request.GetBytes(), 0, 48);
return(reject);
}
ushort LUN = (ushort)request.LUN;
Disk disk = target.Disks[LUN];
uint offset = request.BufferOffset;
uint totalLength = (uint)transfer.CommandDataBuffer.Length;
// Store segment (we only execute the command after receiving all of its data)
Array.Copy(request.Data, 0, transfer.CommandDataBuffer, offset, request.DataSegmentLength);
ISCSIServer.Log(String.Format("[{0}][GetSCSIDataOutResponsePDU] Buffer offset: {1}, Total length: {2}", connectionIdentifier, offset, totalLength));
if (offset + request.DataSegmentLength == totalLength)
{
// Last Data-out PDU
ISCSIServer.Log("[{0}][GetSCSIDataOutResponsePDU] Last Data-out PDU", connectionIdentifier);
byte[] scsiResponse;
SCSIStatusCodeName status = target.ExecuteCommand(transfer.CommandBytes, request.LUN, transfer.CommandDataBuffer, out scsiResponse);
SCSIResponsePDU response = new SCSIResponsePDU();
response.InitiatorTaskTag = request.InitiatorTaskTag;
response.Status = status;
response.Data = scsiResponse;
connection.RemoveTransfer(request.TargetTransferTag);
return(response);
}
else
{
// Send R2T
ReadyToTransferPDU response = new ReadyToTransferPDU();
response.InitiatorTaskTag = request.InitiatorTaskTag;
response.TargetTransferTag = request.TargetTransferTag;
response.R2TSN = transfer.NextR2NSN;
response.BufferOffset = offset + request.DataSegmentLength; // where we left off
response.DesiredDataTransferLength = Math.Min((uint)connection.TargetMaxRecvDataSegmentLength, totalLength - response.BufferOffset);
transfer.NextR2NSN++;
return(response);
}
}
internal static List <ReadyToTransferPDU> GetReadyToTransferPDUs(SCSIDataOutPDU request, ConnectionParameters connection, out List <SCSICommandPDU> commandsToExecute)
{
List <ReadyToTransferPDU> responseList = new List <ReadyToTransferPDU>();
commandsToExecute = new List <SCSICommandPDU>();
ISCSISession session = connection.Session;
TransferEntry transfer = connection.GetTransferEntry(request.TargetTransferTag);
if (transfer == null)
{
throw new InvalidTargetTransferTagException(request.TargetTransferTag);
}
uint offset = request.BufferOffset;
uint totalLength = (uint)transfer.Command.ExpectedDataTransferLength;
// Store segment (we only execute the command after receiving all of its data)
Array.Copy(request.Data, 0, transfer.Command.Data, offset, request.DataSegmentLength);
if (offset + request.DataSegmentLength == totalLength)
{
// Last Data-out PDU
connection.RemoveTransfer(request.TargetTransferTag);
session.CommandsInTransfer.Remove(transfer.Command.CmdSN);
if (session.IsPrecedingCommandPending(transfer.Command.CmdSN))
{
session.DelayedCommands.Add(transfer.Command);
}
else
{
commandsToExecute.Add(transfer.Command);
// Check if delayed commands are ready to be executed
List <SCSICommandPDU> pendingCommands = session.GetDelayedCommandsReadyForExecution();
foreach (SCSICommandPDU pendingCommand in pendingCommands)
{
commandsToExecute.Add(pendingCommand);
}
}
return(responseList);
}
else
{
// RFC 3720: An R2T MAY be answered with one or more SCSI Data-Out PDUs with a matching Target Transfer Tag.
// If an R2T is answered with a single Data-Out PDU, the Buffer Offset in the Data PDU MUST be the same as the one specified
// by the R2T, and the data length of the Data PDU MUST be the same as the Desired Data Transfer Length specified in the R2T.
// If the R2T is answered with a sequence of Data PDUs, the Buffer Offset and Length MUST be within
// the range of those specified by R2T, and the last PDU MUST have the F bit set to 1.
// An R2T is considered outstanding until the last data PDU is transferred.
if (request.Final)
{
// We already sent as many R2T as we could, we will only send R2T if any remained.
if (transfer.NextR2TSN < transfer.TotalR2Ts)
{
// Send R2T
ReadyToTransferPDU response = new ReadyToTransferPDU();
response.InitiatorTaskTag = request.InitiatorTaskTag;
response.TargetTransferTag = request.TargetTransferTag;
response.R2TSN = transfer.NextR2TSN;
response.BufferOffset = transfer.NextOffset; // where we left off
response.DesiredDataTransferLength = Math.Min((uint)connection.TargetMaxRecvDataSegmentLength, totalLength - response.BufferOffset);
responseList.Add(response);
transfer.NextR2TSN++;
transfer.NextOffset += (uint)connection.TargetMaxRecvDataSegmentLength;
}
}
return(responseList);
}
}
internal static List <ISCSIPDU> GetSCSIResponsePDU(SCSICommandPDU command, ISCSITarget target, SessionParameters session, ConnectionParameters connection)
{
// We return either SCSIResponsePDU or List<SCSIDataInPDU>
List <ISCSIPDU> responseList = new List <ISCSIPDU>();
string connectionIdentifier = StateObject.GetConnectionIdentifier(session, connection);
if (command.Write && command.DataSegmentLength < command.ExpectedDataTransferLength)
{
uint transferTag = session.GetNextTransferTag();
// Store segment (we only execute the command after receiving all of its data)
byte[] commandDataBuffer = new byte[command.ExpectedDataTransferLength];
Array.Copy(command.Data, 0, commandDataBuffer, 0, command.DataSegmentLength);
// Send R2T
ReadyToTransferPDU response = new ReadyToTransferPDU();
response.InitiatorTaskTag = command.InitiatorTaskTag;
response.R2TSN = 0; // R2Ts are sequenced per command and must start with 0 for each new command;
response.TargetTransferTag = transferTag;
response.BufferOffset = command.DataSegmentLength;
response.DesiredDataTransferLength = Math.Min((uint)connection.TargetMaxRecvDataSegmentLength, command.ExpectedDataTransferLength - response.BufferOffset);
connection.AddTransfer(transferTag, command.CommandDescriptorBlock, commandDataBuffer, 1);
responseList.Add(response);
return(responseList);
}
byte[] scsiResponse;
SCSIStatusCodeName status = target.ExecuteCommand(command.CommandDescriptorBlock, command.LUN, command.Data, out scsiResponse);
if (!command.Read || status != SCSIStatusCodeName.Good)
{
// RFC 3720: if the command is completed with an error, then the response and sense data MUST be sent in a SCSI Response PDU
SCSIResponsePDU response = new SCSIResponsePDU();
response.InitiatorTaskTag = command.InitiatorTaskTag;
response.Status = status;
response.Data = scsiResponse;
if (command.Read)
{
EnforceExpectedDataTransferLength(response, command.ExpectedDataTransferLength);
}
responseList.Add(response);
}
else if (scsiResponse.Length <= connection.InitiatorMaxRecvDataSegmentLength)
{
SCSIDataInPDU response = new SCSIDataInPDU();
response.InitiatorTaskTag = command.InitiatorTaskTag;
response.Status = status;
response.StatusPresent = true;
response.Final = true;
response.Data = scsiResponse;
EnforceExpectedDataTransferLength(response, command.ExpectedDataTransferLength);
responseList.Add(response);
}
else // we have to split the response to multiple Data-In PDUs
{
int bytesLeftToSend = scsiResponse.Length;
uint dataSN = 0;
while (bytesLeftToSend > 0)
{
int dataSegmentLength = Math.Min(connection.InitiatorMaxRecvDataSegmentLength, bytesLeftToSend);
int dataOffset = scsiResponse.Length - bytesLeftToSend;
SCSIDataInPDU response = new SCSIDataInPDU();
response.InitiatorTaskTag = command.InitiatorTaskTag;
if (bytesLeftToSend == dataSegmentLength)
{
// last Data-In PDU
response.Status = status;
response.StatusPresent = true;
response.Final = true;
}
response.BufferOffset = (uint)dataOffset;
response.DataSN = dataSN;
dataSN++;
response.Data = new byte[dataSegmentLength];
Array.Copy(scsiResponse, dataOffset, response.Data, 0, dataSegmentLength);
responseList.Add(response);
bytesLeftToSend -= dataSegmentLength;
}
}
return(responseList);
}
internal static List <SCSIDataOutPDU> GetWriteData(SessionParameters session, ConnectionParameters connection, ushort LUN, ulong sectorIndex, byte[] data, int bytesPerSector, ReadyToTransferPDU readyToTransfer)
{
List <SCSIDataOutPDU> result = new List <SCSIDataOutPDU>();
// if readyToTransfer.DesiredDataTransferLength <= connection.TargetMaxRecvDataSegmentLength we must send multiple Data-Out PDUs
// We assume DesiredDataTransferLength does not violate session.MaxBurstLength
int numberOfChunks = (int)Math.Ceiling((double)readyToTransfer.DesiredDataTransferLength / connection.TargetMaxRecvDataSegmentLength);
for (int chunkIndex = 0; chunkIndex < numberOfChunks; chunkIndex++)
{
int chunkOffset = chunkIndex * connection.TargetMaxRecvDataSegmentLength;
int chunkLength = (int)Math.Min(connection.TargetMaxRecvDataSegmentLength, readyToTransfer.DesiredDataTransferLength - chunkOffset);
SCSIDataOutPDU dataOut = new SCSIDataOutPDU();
dataOut.BufferOffset = readyToTransfer.BufferOffset + (uint)chunkOffset;
dataOut.Data = ByteReader.ReadBytes(data, (int)dataOut.BufferOffset, chunkLength);
dataOut.TargetTransferTag = readyToTransfer.TargetTransferTag;
dataOut.InitiatorTaskTag = readyToTransfer.InitiatorTaskTag;
if (chunkIndex == numberOfChunks - 1)
{
dataOut.Final = true;
}
result.Add(dataOut);
}
return(result);
}