hackenv_createbridge

#!/usr/bin/env bash

set -o errexit
set -o errtrace

datahome="${XDG_DATA_HOME:-$HOME/.local/share}"
readonly datahome="$datahome/hackenv"

readonly networkname='default'
readonly interfacename='virbr0'

if_network_exists() {
	sudo virsh net-list --all --name | grep "^$networkname\$" > /dev/null
}

# https://stackoverflow.com/a/52814732
create_network() {
	printf "Creating XML network description...\n" >&2

	cat <<- EOF > "$datahome/network.xml"
		<network>
		    <name>$networkname</name>
		    <bridge name="$interfacename"/>
		    <forward/>
		    <ip address="192.168.122.1" netmask="255.255.255.0">
		        <dhcp>
		            <range start="192.168.122.2" end="192.168.122.254"/>
		        </dhcp>
		    </ip>
		</network>
	EOF

	printf "Define the network...\n" >&2
	sudo virsh net-define "$datahome/network.xml"

	printf "Start the network...\n" >&2
	sudo virsh net-start "$networkname"

	printf "Flag the network to automatically start on boot...\n" >&2
	sudo virsh net-autostart "$networkname"

	if ! grep -q "allow $interfacename"; then
		sudo mkdir -p /etc/qemu
		echo "allow $interfacename" | sudo tee -a /etc/qemu/bridge.conf
		sudo chown -R :kvm /etc/qemu
		sudo chmod 640 /etc/qemu/bridge.conf
	fi
}

if_network_exists &&
	printf "Network already exists; exiting...\n" >&2 &&
	exit 0

create_network

printf "Verify that the network was created... " >&2
if_network_exists &&
	printf "success" >&2 ||
	printf "failure" >&2
printf "!\n" >&2