SSHing to RNDIS device (custom distro running 4.4.0) from Ubuntu Server 22.04

Mithrandir_ · 02-23-2023, 09:41 AM

Hello,

I've had this issue forever now. Every time I need to SSH on to my device I need to boot up windows and use Bitvise or Putty to SSH on to my device - for some reason it just doesn't seem to want to initialize whatever needs to be initialized for the device to be recognized either on my native MacOS or on my Ubuntu Server VM.

I've given up on Mac as finding a working RNDIS driver seems to be a nightmare, is not supported by Apple etc. Okay, whatever, I'm pretty much running my linux server all the time anyway because I use it as a build machine for my software.

Now I am determined to get to the bottom of this and finally get my SSH working. I know next to nothing about networking so bear with me.

First things first I ran lsmod | grep rndis on both the target(device) and host(ubuntu server).

on the server I get:

Code:

rndis_wlan
rndis_host
cdc_ether

and some other stuff. So they both seem to have rndis drivers installed.

on the target I get:

Code:

usb_f_rndis            24576  2
u_ether                24576  1 usb_f_rndis
libcomposite           53248 12 usb_f_mass_storage,usb_f_rndis

next I ran ip addr show

server

Code:

 
usb0: <BROADCAST,MULTICAST> mtu 1500 disc noop state DOWN group default qlen 1000
link/ether 8e:92:............ brd ff:ff:ff...........

basically the same on the target:

Code:

2: usb0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 1000
    link/ether fe:af:37:71:a8:f3 brd ff:ff:ff:ff:ff:ff

lsusb yields:

server:

Code:

BUS 001 Device 004: ID 05e8:a4a1 ICC, Inc. NameOfDevice

target:

Code:

Bus 001 Device 001: ID 1d6b:0002

when I disconnect the USB cable and do dmsg I get

server:

Code:

usb 1-3: USB disconnect, device number 4
rndis_host 1-3:1.0 usb0: unregister 'rndis_host' usb-000:00;1d.7-3, RNDIS device

target:

Code:

configfs-gadget gadget: high-speed config #1: c

upon connect:

server:

Code:

rndis_host 1-3:1.0 usb0: register 'rndis_host' at usb-0000:00:1d.7-3, RNDIS device 02:4b:9d:8b:a8:a5

target, sometimes nothing, sometimes

Code:

configfs-gadget gadget: high-speed config #1: c

and ifconfig -a looking at usb0

server:

Code:

usb0: flags=4098<BROADCAST,MULTICAST> mtu 1500
ether 56:f6:0a..... txquelen 1000 (Ethernet)
RX packets 0
RX errors 0
TX packets 0
TX errors 0

target

Code:

usb0      Link encap:Ethernet  HWaddr FE:AF:37:....
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

I know that once the RNDIS driver is working the IP addres is supposed to be 192.168.236.2

This works fine on windows...

smallpond · 02-23-2023, 02:08 PM

How are you setting the IP on the server and bringing up the interfface? Is it using NetworkManager?

Mithrandir_ · 02-24-2023, 02:31 AM

Quote:

Originally Posted by smallpond

How are you setting the IP on the server and bringing up the interfface? Is it using NetworkManager?

The usb0 gadget pops up on its own when I plug in the device. AFAIK RNDIS is supposed to set up an ethernet-over-usb connection on its own, but for some reason it doesn't want to do that when it's connected to Linux. For windows it does everything on its own and I can just SSH on the device.

Not really sure what you mean by network manager? I have no GUI on either side - just terminals.

Mithrandir_ · 02-24-2023, 02:41 AM

I should probably mention that the Ubuntu server is running as a VM in Parallels on my Macbook Pro, which is the host. The network adapter is bridged between the two.

Mithrandir_ · 02-24-2023, 05:54 AM

I tried assigning both parties a static address with sudo ifconfig usb0 IPADDRESS netmask 255.255.255.0

They both look something like this now, but I am still unable to ping between them:

Code:

usb0      Link encap:Ethernet  HWaddr 9E:11:8A:58:16:AF
          inet addr:192.168.137.2  Bcast:192.168.137.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:139 errors:0 dropped:13 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:11072 (10.8 KiB)  TX bytes:516 (516.0 B)

smallpond · 02-28-2023, 08:29 AM

In addition to IP you also need to add a route to the routing table.