USB Switch using usbip

switch

#!/bin/bash
set -x

# This is a tool that emulates a usb switch by leveraging usbip
# The script is needed on two machines

#      PC: 1                                 PC: 2
#      ###############                       ##############
#      #             #    -- ./switch -->    #            #
#      #   SERVER    #                       #   CLIENT   #
#      #             #    <-- ./switch --    #            #
#      ###############                       ##############
#            |                                  ^
#           bus 1-2  - - - - - usbip - - - - - /  
#            |      		              |
#        #############                     + + + + + + +
#        # keyboard1 #                     + keyboard1 +
#        #############                     + + + + + + +

# TIP:  You can key-bind this script or call it from console

# NOTE: you need the usbipd service running on the server;
#       do: " sudo usbipd -D " or enable and start the usbipd service as usual

# NOTE: in void linux, the packaged usbipd service entry doesn't work... do it manually

sudo modprobe usbip_host usbip_core || exit 1

#######################
####  CONFIG START

## The $SERVER and $CLIENT are adresses; but the hostnames are
### 	in the machines' /etc/hostname files respectively
SERVER=${SERVER-svwork}
SERVER_HOSTNAME=${SERVER_HOSTNAME-svwork}

CLIENT=${CLIENT-hyrican}
CLIENT_HOSTNAME=${CLIENT_HOSTNAME-void-usb}

# Multiple are allowed, e.g.  usb_buses="1-5 1-3 1-7"
# Tip: to find out what devices you'd like to share from the server, do: sudo usbip list -l
usb_buses="1-5"

####  CONFIG END
######################

bind_usb() {
	sudo usbip bind -b $1
}

release_usb() {
	sudo usbip unbind -b $1
}

attach_usb() {
	ssh $CLIENT "sudo usbip attach -r $SERVER -b $1"
}

release_usb() {
	ssh $SERVER "sudo usbip unbind -b $1"
}

release_usb_locally() {
	sudo usbip unbind -b $1
}

check_client() {
	# Also loads vhci-hcd on client, just in case
	ssh -q -o "ConnectTimeout=1" $USER@$CLIENT "sudo modprobe vhci-hcd && exit"
	return $?
}

if [[ "$HOSTNAME" == "$CLIENT_HOSTNAME" ]] ; then
	echo "Releasing devices..."
	for bus in $usb_buses ; do release_usb $bus ; done ; exit
	elif check_client; then
		for bus in $usb_buses ; do
			if bind_usb $bus; then
				attach_usb $bus
			else
				release_usb_locally $bus
				release_usb $bus
			fi
		done
fi