docker-vpn/start-openvpn.sh

#!/usr/bin/env bash

set -o pipefail

OVPN_LOG_FILE=/tmp/ovpnlog.txt

change_hostname() {
    echo VPNDOCKER > /etc/hostname
}

create_net_dev() {
    mkdir -p /dev/net
    mknod /dev/net/tun c 10 200
    chmod 600 /dev/net/tun
}

connect_vpn() {
    sed -e 's|^up .*$|up /etc/openvpn/up.sh|' \
        -e 's|^down .*$|down /etc/openvpn/down.sh|' \
        -e 's|^auth-user-pass.*$|auth-user-pass|' \
        "$OVPN_CONFIGURATION_FILE" > /tmp/ovpn.conf
    openvpn --config /tmp/ovpn.conf --log "$OVPN_LOG_FILE" --daemon
}

get_ip() {
    nsout="$(nslookup -timeout=1 myip.opendns.com resolver1.opendns.com)"
    if [ "$?" != 0 ]; then
        echo "WARN: Failed to run nslookup" >&2
    fi
    echo "$nsout" | grep -o 'Address:.*' | grep -Eo '(\d+\.?){4}' | tail -n1
}

print_ip() {
    echo "VPN IP: $(get_ip)"
}

switch_user() {
    su -c "cd $OVPN_WORKDIR && "'$SHELL' -l "$OVPN_USER"
}

own_ip="$(get_ip)"
echo "OWN IP: $own_ip"
if [ "$own_ip" = "" ]; then
    echo "ERROR: Failed to lookup own ip, aborting" >&2
    exit 1
fi
change_hostname
create_net_dev
connect_vpn
for _ in {1..100}; do
    vpn_ip="$(get_ip)"
    if [ "$vpn_ip" = "$own_ip" ] || [ "$vpn_ip" = "" ]; then
        sleep .1
    else
        break
    fi
done
if [ "$vpn_ip" = "$own_ip" ] || [ "$vpn_ip" = "" ]; then
    echo "ERROR: Failed to connect to VPN (vpn_ip=$vpn_ip), aborting" >&2
    echo "Ovpn log:" >&2
    cat "$OVPN_LOG_FILE" >&2
    exit 1
fi
echo "VPN IP: $vpn_ip"
switch_user