#!/bin/sh
#
# A post-up/down hook to automatically create/delete a 'sec' VLAN
# device, and a dedicated, host-scoped, IP for IPSec (v4 only).
#
# Copyright 2013 Guilhem Moulin <guilhem@fripost.org>
#
# Licensed under the GNU GPL version 3 or higher.
#

set -ue
PATH=/usr/sbin:/usr/bin:/sbin:/bin

if=sec0
ip=172.16.0.1/32

# Ignore the loopback interface and non inet4 families.
[ "$IFACE" != lo -a "$ADDRFAM" = inet ] || exit 0

# Only the device with the default, globally-scoped route, is of
# interest here.
[ "$( /bin/ip -4 route show to default scope global \
    | sed -nr '/^default via \S+ dev (\S+).*/ {s//\1/p;q}' )" \
  = \
  "$IFACE" ] || exit 0

case "$MODE" in
    start) # Don't create $if if it's already there
           /bin/ip -o link show | grep -qE "^[0-9]+:\s+$if" && exit 0
        
           # Create a new VLAN $IFACE on physical device $if. This is
           # required otherwise charon thinks the left peer is that
           # host-scoped, non-routable IP.
           /bin/ip link    add link "$IFACE" name "$if" type vlan id 2713
           /bin/ip address add "$ip" dev "$if" scope host
           /bin/ip link    set dev "$if" up
    ;;
    stop)  # Don't create $if if it's no there
           /bin/ip -o link show | grep -qE "^[0-9]+:\s+$if" || exit 0
        
           # Deactivate the VLAN
           /bin/ip link set dev "$if" down
    ;;
esac