qtunnel-connect

#!/bin/bash

###########################################################################
##  qtunnel-connect
##
## Handles DHCP-source DNS addresses & link notification for Qubes VPN VMs.
## To use, set as 'up' and 'down' script with parameter in your VPN config.
##
## Use 'tunnel_dns' environment var as override/alternative.
## In openvpn config, format is: setenv tunnel_dns 'X.X.X.X  Y.Y.Y.Y [...]'
##
## Christopher Laprise, 2018  -  https://github.com/tasket

set -e
export PATH="$PATH:/usr/sbin:/sbin:/bin"
nspath=/var/run/qubes/qubes-tunnel-ns
rm -f $nspath

case "$1" in
up|test-up)
    rm -f $nspath
    if [[ -z "$tunnel_dns" ]] ; then
        # Parses DHCP option variables to set DNS address translation:
        for optionname in ${!foreign_option_*} ; do
            option="${!optionname}"
            unset fops; fops=($option)
            if [ ${fops[1]} == "DNS" ] ; then tunnel_dns="${fops[2]} $tunnel_dns" ; fi
        done
    fi

;;&
up)
    if [[ -n "$tunnel_dns" ]] ; then
        # Set DNS address translation in firewall:
        echo "$tunnel_dns " >$nspath
        echo "Using DNS servers $tunnel_dns"
        iptables -t nat -F PR-QBS
        # Securely restart firewall (Qubes ver <4 only)
        if ! iptables -L QBS-FORWARD; then
            systemctl restart qubes-firewall
        else
            . /var/run/qubes/qubes-ns
            q_addr=""
            for DNS in $tunnel_dns; do
                iptables -t nat -I PR-QBS $q_addr -i vif+ -p tcp --dport 53 -j DNAT --to $DNS
                iptables -t nat -I PR-QBS $q_addr -i vif+ -p udp --dport 53 -j DNAT --to $DNS
                q_addr="-d $NS1"
            done
        fi
        su - -c 'notify-send "$(hostname): LINK IS UP." --icon=network-idle' user
    else
        su - -c 'notify-send "$(hostname): LINK UP, NO DNS!" --icon=dialog-error' user
    fi

;;
test-up)

##  Use test-up parameter to test your basic VPN link before enabling firewall script.
##  Do NOT use beyond testing period.
    if [[ -z "$tunnel_dns" ]]; then echo "NO DNS ADDRESS FOUND."; exit 0; fi
    [ -e /etc/resolv.vpnbak ] || cp -a /etc/resolv.conf /etc/resolv.vpnbak
    rm /etc/resolv.conf
    for DNS in $tunnel_dns; do
        echo "nameserver $DNS" >>/etc/resolv.conf
    done
    /usr/lib/qubes/qubes-setup-dnat-to-ns
    su - -c 'notify-send "$(hostname): TEST LINK IS UP." --icon=network-idle' user

;;
down)
    iptables -t nat -F PR-QBS
    su - -c 'notify-send "$(hostname): LINK IS DOWN !" --icon=dialog-error' user

;;
esac