ext_if="ng0"
int_if="re0"
int_net="192.168.1.0/24"
vpn_if="tap0"
vpn_net="10.117.35.202"
ext_gw="109.195.67.254"

nat on $ext_if from !($ext_if) -> ($ext_if)
nat on $vpn_if from $int_if:network -> ($vpn_if)

pass in log on $ext_if reply-to ($ext_if $ext_gw) from any to any keep state
pass out log on $ext_if from any to any