Error: Cannot find device "usb0" under Ubuntu 18.04

[nasser]

My PW1, PW3 and KT3 were connecting fine, both over USB0 and Wi-Fi, with my PC OS being Ubuntu version 14.04 (32-bit).
I recently upgraded the PC to Ubuntu version 18.04 (64-bit) and was slowly restoring all my old programs and tweaks.
But now I find that I'm only able to connect through ssh over Wi-Fi to all the 3 Kindles - from the command line or through midnight commander's "shell link" option.
Connecting through USB0 doesn't work anymore. I keep getting these error messages:

• Cannot find device "usb0"
• Requesting an ethernet connection address for "Wired connection 1"

I've regenerated the ssh-keygen file from PC side and copied it as "authorized_keys" to all the kindles under /mnt/us/usbnet/etc.

Any clue to fixing this?

[NiLuJe]

Check dmesg, some distributions rename network interfaces based on their hardware "location", to make them unique.

i.e., my usual USB port is lovingly named enp0s20f0u10 on my box.

[nasser]

Thanks a lot, NiLuJe!
I found the following lines in dmesg output(as soon as I connected my PW1):

[20228.272172] usb 1-1: new high-speed USB device number 5 using ehci-pci
[20228.435300] usb 1-1: New USB device found, idVendor=0525, idProduct=a4a2
[20228.435311] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[20228.435317] usb 1-1: Product: RNDIS/Ethernet Gadget
[20228.435324] usb 1-1: Manufacturer: Linux 2.6.31-rt11-lab126 with fsl-usb2-udc
[20229.149081] cdc_ether 1-1:1.0 usb0: register 'cdc_ether' at usb-0000:00:1d.7-1, CDC Ethernet Device, ee:49:00:00:00:00
[20229.149330] usbcore: registered new interface driver cdc_ether
[20229.152421] usbcore: registered new interface driver cdc_subset
[20229.280413] cdc_ether 1-1:1.0 enp0s29f7u1: renamed from usb0

From the last line, I copied enp0s29f7u1 into my old USB0 script, replacing USB0:

sudo ip address add 192.168.15.201 peer 192.168.15.244 dev enp0s29f7u1

Now it works!

[NiLuJe]

That name won't change *for this specific USB port*, if you happen to plug it in somewhere else, you'll have to check for the proper name again .

[nasser]

Thanks again for the tips, NiLuJe!
I tried the 3 available ports on my PC and I got these:

• enp0s29f7u1
• enp0s29f7u2
• enp0s29f7u4

Only the last character is changing.

Maybe a script can be made which changes the device name based on which port the kindle is plugged in...

I tried a brute force script:

sudo ip address add 192.168.15.201 peer 192.168.15.244 dev enp0s29f7u1
sudo ip address add 192.168.15.201 peer 192.168.15.244 dev enp0s29f7u2
sudo ip address add 192.168.15.201 peer 192.168.15.244 dev enp0s29f7u4

...which surprisingly seems to work!

[NiLuJe]

IIRC, there's an udev command to decipher those, too .

As well as possibly doing away with the rename entirely, although that may not be an option anymore on distros that made the switch to systemd (or at all)...

[nasser]

I tried this "all-in-one" script to cater to all the 9 combinations of 3 kindle models(or even 3 same model kindles) and 3 USB ports on the PC:

for i in 244 245 246
  do
    for j in enp0s29f7u1 enp0s29f7u2 enp0s29f7u4
      do
        sudo ip address add 192.168.15.201 peer 192.168.15.$i dev $j
      done
  done

But, both here as well as in a single port/single kindle version of the script, a prior manual disconnect is required, to stop the PC's network from futilely trying to connect to a non-existent ethernet network. If this is not done, it is possible to login to the kindle, but the ssh session soon freezes and becomes unresponsive.

Of course, there are always some error messages referring to the 2 unconnected USB ports, but these don't seem to do any other harm.

Any script possible to automate the manual disconnect? I tried sudo ifconfig enp0s29f7u1 down, but it didn't work. Trying to login to the kindle gave a message that no route was found.

[knc1]

As posted elsewhere here, disable network manager.