choose_vpn_config.sh

#!/usr/bin/env bash

# base URL of control server (default https://controlplane.tailscale.com)
TAILSCALE_LOGIN_SERVER="https://controlplane.tailscale.com"

# Unix username to allow to operate on tailscaled without sudo
TAILSCALE_OPERATOR="$(whoami)"

# case-insensitive matching, 7 rows, select row with index 1 by default (the "up" option)
ROFI_ARGS="-theme Arc-Dark -p Tailscale -i -lines 7 -selected-row 1"

# define common options
declare -A options
options[" up"]="up \
                 --login-server ${TAILSCALE_LOGIN_SERVER} \
                 --operator ${TAILSCALE_OPERATOR} \
                 --accept-routes \
                 --shields-up \
                 --reset"
options[" down"]="down"

# get tailscale status, then add one rofi option per available exit node
status=$(curl --silent --fail --unix-socket /var/run/tailscale/tailscaled.sock http://local-tailscaled.sock/localapi/v0/status)
for dnsname in $(echo ${status} | jq --raw-output '.Peer[] | select(.ExitNodeOption) | .DNSName'); do
    options[" up (${dnsname} as exit node)"]="up \
                                                --login-server ${TAILSCALE_LOGIN_SERVER} \
                                                --operator ${TAILSCALE_OPERATOR} \
                                                --exit-node ${dnsname} \
                                                --accept-routes \
                                                --shields-up \
                                                --reset"
done

main() {
    # print the options separated by newline characters, sort them, then call rofi
    result=$(echo -e "$(printf "%s\n" "${!options[@]}" | sort)" | rofi -dmenu $ROFI_ARGS)

    # rofi exit code == 0: normal operation
    # 10 <= exit code <= 28: keybindings used
    # anything else: canceled or something unforeseen happened
    if [[ $? == 0 || ($? -ge 10 && $? -le 28) ]]; then
        command=${options[$result]}
        tailscale $command

        # alternative if you want to use polkit for rights elevation instead of the '--operator' option:
        # pkexec tailscale $command
    fi
}

main