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);
}
}
