SCSI Network Card

SCSI Network Card emulation

The aim is to provide network capabilities through SCSI interface emulated by PiSCSI. This documentation is for developer who would like to contribute to this project.

Current status

This is not yet ready and still under development. Packets go through piscsi0 tun/tap and are read by PiSCSI service, and are sent to SCSI. I haven't been able to verify the packet arrived on the Mac yet.

How does it work?

Packets can come from wlan0 or from localhost, they are sent to a tun/tap virtual interface named piscsi0. The PiSCSI software connects to piscsi0 and reads the packets, then write those packets to the SCSI interface. On the Mac, the device driver, reads the packets from the SCSI physical port of the Mac and provide them to the System. Same operation happen in the other direction when packets are sent from the Mac to the SCSI (thanks the driver). PiSCSI reads the packets from the SCSI emulation and write then to the virtual network interface piscsi0, packets can then travel to the internet through wlan0.

 
 [  wlan0   ] <---> [   piscsi0      ] <---> [ PiSCSI + SCSI NIC Emulation ] <---> SCSI <--> [ Mac OS Device Driver ] <-> [ Mac System ]
 [ internet ]       [ tun virtual ]       [ read packets from piscsi0 and  ]
                    [  interface  ]       [ write them to the SCSI.     ]
                                          [ read the packets from SCSI  ]
                                          [ and write them to piscsi0.     ]

Tools to debug network

In order to debug how the packets are being transferred these tools can be useful.

sudo apt-get install iputils-arping tcpdump

Debugging

check the logs

tail -f /var/log/piscsi.log

Tools

arping

arping -c 5 -I piscsi0 D6:90:8C:7A:17:6E
arping -c 5 -I piscsi0 192.168.0.1

TCP Dump

Filter tcp traffic on the tun/tap interface

sudo tcpdump -I piscsi0 tcp