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 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);
}
