#!/bin/bash

# let host and guests talk to each other over macvlan
# configures a macvlan interface on the hypervisor
# run this on the hypervisor (e.g. in /etc/rc.local)
# made for IPv4; need modification for IPv6
# meant for a simple network setup with only eth0,
# and a static (manual) ip config
# Evert Mouw, 2013

HWLINK=eth0
MACVLN=macvlan0
TESTHOST=www.google.com

# ------------
# wait for network availability
# ------------

while ! ping -q -c 1 $TESTHOST > /dev/null
do
    echo "$0: Cannot ping $TESTHOST, waiting another 5 secs..."
    sleep 5
done

# ------------
# get network config
# ------------

IP=$(ip address show dev $HWLINK | grep "inet " | awk '{print $2}')
NETWORK=$(ip -o route | grep $HWLINK | grep -v default | awk '{print $1}')
GATEWAY=$(ip -o route | grep default | awk '{print $3}')

# ------------
# setting up $MACVLN interface
# ------------

ip link add link $HWLINK $MACVLN type macvlan mode bridge
ip address add $IP dev $MACVLN
ip link set dev $MACVLN up

# ------------
# routing table
# ------------

# empty routes
ip route flush dev $HWLINK
ip route flush dev $MACVLN

# add routes
ip route add $NETWORK dev $MACVLN metric 0

# add the default gateway
ip route add default via $GATEWAY

echo 1 > /sys/module/kvm/parameters/ignore_msrs