kvm-networking

#!/bin/bash
#
# Setups up a proxy aRP bridge to wlan0
#

#
# Note this will need to be chnaged to your user
KVM_USER=ewhite

kvm_if_up() {
  tunctl -u $KVM_USER -t tap0

  sysctl net.ipv4.ip_forward=1
  sysctl net.ipv4.conf.wlan0.proxy_arp=1
  sysctl net.ipv4.conf.tap0.proxy_arp=1

  ip link set dev tap0 up

  if [ -z ${KVM_IP_STATIC} ]; then
    echo "No route to guest configured!"
    echo "***"
    echo "Add one using:"
    echo "  sudo route add <IP> dev tap0"
    echo "***"
  else
    echo "Setting up a route to guest: ${KVM_IP_STATIC}"
    route add -host ${KVM_IP_STATIC} dev tap0
  fi

  route -n
}

kvm_if_dn() {
  sysctl net.ipv4.ip_forward=0
  sysctl net.ipv4.conf.wlan0.proxy_arp=0
  sysctl net.ipv4.conf.tap0.proxy_arp=0

  ip link set dev tap0 down

  tunctl -d tap0
}

if [[ $EUID -ne 0 ]]; then
  echo "This script must be run as root" 1>&2
  exit 1
else
  case "$1" in
    start)
      kvm_if_up
      ;;
    stop)
      kvm_if_dn
      ;;
    *)
      echo "Usage: $0 {start|stop}"
      ;;
    esac
fi

exit 0