This is a project to provide an implementation of the SCSI protocol as well as iSCSI protocol written in .NET Core 3.
This project makes heavy use of the Span<> funtionality of C# and as a result the code, which I believe is quite well structured suffers a few limitations in architecture. Since it's not possible to use fixed position fields in structures in C# and it's also impossible to define fixed sized arrays in structures, the project gets a little ugly at times by employing private padding fields to make the structures the right sizes.
[StructLayout(LayoutKind.Sequential,Pack=1)]
public struct BasicHeaderSegment : ISCSISegment
{
private uint OpcodeFieldsBE;
private uint LengthsBE;
private ulong LunOpcodeSpecificFieldsBE;
private uint InitiatorTaskTagBE;
private ulong OpcodeSpecificFields1BE;
private ulong OpcodeSpecificFields2BE;
private ulong OpcodeSpecificFields3BE;
private uint OpcodeSpecificFields4BE;
...
}This is an example of ugly padding which was added to make things line up.
First of all, I can't seem to find any memory safe implementations of iSCSI on the Internet. Pretty much all implementationsa I can find are written in C and the code is pretty much unmaintainable.
I need an iSCSI or FCoE implementation of a SCSI target capable of supporting automated server management. This doesn't sound very difficult, but using existing implementations of iSCSI, it's a bit of a mess. In my case, using Cisco UCS, I want to be able to have a different LUN 0 for each target, but it should be differentiated by initiator and authentication. I want to use the same target name and LUN for all blades.
In addition, I want to support disk image files. I'm considering just supporting RAM disk, QCOW2 and Linux LVM at this time, but I may add support for more later on.
At the moment, I'm making use of the iscsi-scsi-10TB-data-device.zip sample file found on the Wireshark Wiki as a starting point for development.
At this time, the code is capable of fully parsing and reproducing the first 8 packets of the file. This is quite a bit further along than it sounds. From what I can see, there are only about 2-dozen packet types needed to implement iSCSI at least at a fairly privative level. Not to mention that there's a LOT of code coverage in place for unit tests on this code.