#!/bin/bash
# This file is part of cloud-init.
# See LICENSE file for copyright and license info.
set -f
VERBOSITY=0
KVM_PID=""
DRY_RUN=false
TEMP_D=""
DEF_BRIDGE="virbr0"
TAPDEVS=( )
# OVS_CLEANUP gets populated with bridge:devname pairs used with ovs
OVS_CLEANUP=( )
MAC_PREFIX="52:54:00:12:34"
# allow this to be set externally.
_QEMU_SUPPORTS_FILE_LOCKING="${_QEMU_SUPPORTS_FILE_LOCKING}"
KVM="kvm"
declare -A KVM_DEVOPTS
error() { echo "$@" 1>&2; }
fail() { [ $# -eq 0 ] || error "$@"; exit 1; }
bad_Usage() { Usage 1>&2; [ $# -eq 0 ] || error "$@"; exit 1; }
randmac() {
# return random mac addr within final 3 tokens
local random=""
random=$(printf "%02x:%02x:%02x" \
"$((${RANDOM}%256))" "$((${RANDOM}%256))" "$((${RANDOM}%256))")
padmac "$random"
}
cleanup() {
[ -z "${TEMP_D}" -o ! -d "${TEMP_D}" ] || rm -Rf "${TEMP_D}"
[ -z "${KVM_PID}" ] || kill "$KVM_PID"
if [ ${#TAPDEVS[@]} -ne 0 ]; then
local name item
for item in "${TAPDEVS[@]}"; do
[ "${item}" = "skip" ] && continue
debug 1 "removing" "$item"
name="${item%:*}"
if $DRY_RUN; then
error ip tuntap del mode tap "$name"
else
ip tuntap del mode tap "$name"
fi
[ $? -eq 0 ] || error "failed removal of $name"
done
if [ ${#OVS_CLEANUP[@]} -ne 0 ]; then
# with linux bridges, there seems to be no harm in just deleting
# the device (not detaching from the bridge). However, with
# ovs, you have to remove them from the bridge, or later it
# will refuse to add the same name.
error "cleaning up ovs ports: ${OVS_CLEANUP[@]}"
if ${DRY_RUN}; then
error sudo "$0" tap-control ovs-cleanup "${OVS_CLEANUP[@]}"
else
sudo "$0" tap-control ovs-cleanup "${OVS_CLEANUP[@]}"
fi
fi
fi
}
debug() {
local level=${1}; shift;
[ "${level}" -gt "${VERBOSITY}" ] && return
error "${@}"
}
Usage() {
cat <<EOF
Usage: ${0##*/} [ options ] -- kvm-args [ ... ]
run kvm with a tap interface.
options:
-n | --netdev NETDEV netdev can be 'user' or a bridge.
default is to bridge to $DEF_BRIDGE
-d | --disk DISK.img attach DISK.img as a disk (via virtio)
--dry-run only report what would be done
--uefi boot with efi
--uefi-nvram=FILE boot with efi, using nvram settings in FILE
if FILE not present, copy from defaults.
NETDEV:
Above, 'NETDEV' is a comma delimited string
The first field must be
* bridge name: (br0 or virbr0): attach a device to this bridge
* literal 'user': use qemu user networking
Additional fields are optional, and can be anything that is acceptable
to kvm either as:
* '-device virtio-net-pci' option (see 'kvm -device virtio-net-pci,?')
* '-net [user|tap]' option
Example:
* xkvm --netdev br0,macaddr=:05 -- -drive file=disk.img,if=virtio -curses
attach a tap device to bridge 'br0' with mac address
'${MAC_PREFIX}:05'
* xkvm --netdev user,mac=random --netdev br1,model=e1000,mac=auto -- -curses
attach virtio user networking nic with random mac address
attach tap device to br1 bridge as e1000 with unspecified mac
* xkvm --disk disk1.img
EOF
}
isdevopt() {
local model="$1" input="${2%%=*}"
local out="" opt="" opts=()
if [ -z "${KVM_DEVOPTS[$model]}" ]; then
out=$($KVM -device "$model,?" 2>&1) &&
out=$(echo "$out" | sed -e "s,[^.]*[.],," -e 's,=.*,,') &&
KVM_DEVOPTS[$model]="$out" ||
{ error "bad device model $model?"; exit 1; }
fi
opts=( ${KVM_DEVOPTS[$model]} )
for opt in "${opts[@]}"; do
[ "$input" = "$opt" ] && return 0
done
return 1
}
qemu_supports_file_locking() {
# hackily check if qemu has file.locking in -drive params (LP: #1716028)
if [ -z "$_QEMU_SUPPORTS_FILE_LOCKING" ]; then
# The only way we could find to check presense of file.locking is
# qmp (query-qmp-schema). Simply checking if the virtio-blk driver
# supports 'share-rw' is expected to be equivalent and simpler.
isdevopt virtio-blk share-rw &&
_QEMU_SUPPORTS_FILE_LOCKING=true ||
_QEMU_SUPPORTS_FILE_LOCKING=false
debug 1 "qemu supports file locking = ${_QEMU_SUPPORTS_FILE_LOCKING}"
fi
[ "$_QEMU_SUPPORTS_FILE_LOCKING" = "true" ]
return
}
padmac() {
# return a full mac, given a subset.
# assume whatever is input is the last portion to be
# returned, and fill it out with entries from MAC_PREFIX
local mac="$1" num="$2" prefix="${3:-$MAC_PREFIX}" itoks="" ptoks=""
# if input is empty set to :$num
[ -n "$mac" ] || mac=$(printf "%02x" "$num") || return
itoks=( ${mac//:/ } )
ptoks=( ${prefix//:/ } )
rtoks=( )
for r in ${ptoks[@]:0:6-${#itoks[@]}} ${itoks[@]}; do
rtoks[${#rtoks[@]}]="0x$r"
done
_RET=$(printf "%02x:%02x:%02x:%02x:%02x:%02x" "${rtoks[@]}")
}
make_nics_Usage() {
cat <<EOF
Usage: ${0##*/} tap-control make-nics [options] bridge [bridge [..]]
make a tap device on each of bridges requested
outputs: 'tapname:type' for each input, or 'skip' if nothing needed.
type is one of 'brctl' or 'ovs'
EOF
}
make_nics() {
# takes input of list of bridges to create a tap device on
# and echos either 'skip' or
# <tapname>:<type> for each tap created
# type is one of "ovs" or "brctl"
local short_opts="v"
local long_opts="--verbose"
local getopt_out=""
getopt_out=$(getopt --name "${0##*/} make-nics" \
--options "${short_opts}" --long "${long_opts}" -- "$@") &&
eval set -- "${getopt_out}" || { make_nics_Usage 1>&2; return 1; }
local cur="" next=""
while [ $# -ne 0 ]; do
cur=${1}; next=${2};
case "$cur" in
-v|--verbose) VERBOSITY=$((${VERBOSITY}+1));;
--) shift; break;;
esac
shift;
done
[ $# -ne 0 ] || {
make_nics_Usage 1>&2; error "must give bridge";
return 1;
}
local owner="" ovsbrs="" tap="" tapnum="0" brtype="" bridge=""
[ "$(id -u)" = "0" ] || { error "must be root for make-nics"; return 1; }
owner="${SUDO_USER:-root}"
ovsbrs=""
if command -v ovs-vsctl >/dev/null 2>&1; then
out=$(ovs-vsctl list-br)
out=$(echo "$out" | sed "s/\n/,/")
ovsbrs=",$out,"
fi
for bridge in "$@"; do
[ "$bridge" = "user" ] && echo skip && continue
[ "${ovsbrs#*,${bridge},}" != "$ovsbrs" ] &&
btype="ovs" || btype="brctl"
tapnum=0;
while [ -e /sys/class/net/tapvm$tapnum ]; do tapnum=$(($tapnum+1)); done
tap="tapvm$tapnum"
debug 1 "creating $tap:$btype on $bridge" 1>&2
ip tuntap add mode tap user "$owner" "$tap" ||
{ error "failed to create tap '$tap' for '$owner'"; return 1; }
ip link set "$tap" up 1>&2 || {
error "failed to bring up $tap";
ip tuntap del mode tap "$tap";
return 1;
}
if [ "$btype" = "ovs" ]; then
ovs-vsctl add-port "$bridge" "$tap" 1>&2 || {
error "failed: ovs-vsctl add-port $bridge $tap";
ovs-vsctl del-port "$bridge" "$tap"
return 1;
}
else
ip link set "$tap" master "$bridge" 1>&2 || {
error "failed to add tap '$tap' to '$bridge'"
ip tuntap del mode tap "$tap";
return 1
}
fi
echo "$tap:$btype"
done
}
ovs_cleanup() {
[ "$(id -u)" = "0" ] ||
{ error "must be root for ovs-cleanup"; return 1; }
local item="" errors=0
# TODO: if get owner (SUDO_USERNAME) and if that isn't
# the owner, then do not delete.
for item in "$@"; do
name=${item#*:}
bridge=${item%:*}
ovs-vsctl del-port "$bridge" "$name" || errors=$((errors+1))
done
return $errors
}
quote_cmd() {
local quote='"' x="" vline=""
for x in "$@"; do
if [ "${x#* }" != "${x}" ]; then
if [ "${x#*$quote}" = "${x}" ]; then
x="\"$x\""
else
x="'$x'"
fi
fi
vline="${vline} $x"
done
echo "$vline"
}
get_bios_opts() {
# get_bios_opts(bios, uefi, nvram)
# bios is a explicit bios to boot.
# uefi is boolean indicating uefi
# nvram is optional and indicates that ovmf vars should be copied
# to that file if it does not exist. if it exists, use it.
local bios="$1" uefi="${2:-false}" nvram="$3"
local ovmf_dir="/usr/share/OVMF"
local bios_opts="" pflash_common="if=pflash,format=raw"
unset _RET
_RET=( )
if [ -n "$bios" ]; then
_RET=( -drive "${pflash_common},file=$bios" )
return 0
elif ! $uefi; then
return 0
fi
# ovmf in older releases (14.04) shipped only a single file
# /usr/share/ovmf/OVMF.fd
# newer ovmf ships split files
# /usr/share/OVMF/OVMF_CODE.fd
# /usr/share/OVMF/OVMF_VARS.fd
# with single file, pass only one file and read-write
# with split, pass code as readonly and vars as read-write
local joined="/usr/share/ovmf/OVMF.fd"
local code="/usr/share/OVMF/OVMF_CODE.fd"
local vars="/usr/share/OVMF/OVMF_VARS.fd"
local split="" nvram_src=""
if [ -e "$code" -o -e "$vars" ]; then
split=true
nvram_src="$vars"
elif [ -e "$joined" ]; then
split=false
nvram_src="$joined"
elif [ -n "$nvram" -a -e "$nvram" ]; then
error "WARN: nvram given, but did not find expected ovmf files."
error " assuming this is code and vars (OVMF.fd)"
split=false
else
error "uefi support requires ovmf bios: apt-get install -qy ovmf"
return 1
fi
if [ -n "$nvram" ]; then
if [ ! -f "$nvram" ]; then
cp "$nvram_src" "$nvram" ||
{ error "failed copy $nvram_src to $nvram"; return 1; }
debug 1 "copied $nvram_src to $nvram"
fi
else
debug 1 "uefi without --uefi-nvram storage." \
"nvram settings likely will not persist."
nvram="${nvram_src}"
fi
if [ ! -w "$nvram" ]; then
debug 1 "nvram file ${nvram} is readonly"
nvram_ro="readonly"
fi
if $split; then
# to ensure bootability firmware must be first, then variables
_RET=( -drive "${pflash_common},file=$code,readonly" )
fi
_RET=( "${_RET[@]}"
-drive "${pflash_common},file=$nvram${nvram_ro:+,${nvram_ro}}" )
}
main() {
local short_opts="hd:n:v"
local long_opts="bios:,help,dowait,disk:,dry-run,kvm:,no-dowait,netdev:,uefi,uefi-nvram:,verbose"
local getopt_out=""
getopt_out=$(getopt --name "${0##*/}" \
--options "${short_opts}" --long "${long_opts}" -- "$@") &&
eval set -- "${getopt_out}" || { bad_Usage; return 1; }
local bridge="$DEF_BRIDGE" oifs="$IFS"
local netdevs="" need_tap="" ret="" p="" i="" pt="" cur="" conn=""
local kvm="" kvmcmd="" archopts=""
local def_disk_driver=${DEF_DISK_DRIVER:-"virtio-blk"}
local def_netmodel=${DEF_NETMODEL:-"virtio-net-pci"}
local bios="" uefi=false uefi_nvram=""
archopts=( )
kvmcmd=( )
netdevs=( )
addargs=( )
diskdevs=( )
diskargs=( )
# dowait: run qemu-system with a '&' and then 'wait' on the pid.
# the reason to do this or not do this has to do with interactivity
# if detached with &, then user input will not go to xkvm.
# if *not* detached, then signal handling is blocked until
# the foreground subprocess returns. which means we can't handle
# a sigterm and kill the qemu-system process.
# We default to dowait=false if input and output are a terminal
local dowait=""
[ -t 0 -a -t 1 ] && dowait=false || dowait=true
while [ $# -ne 0 ]; do
cur=${1}; next=${2};
case "$cur" in
-h|--help) Usage; exit 0;;
-d|--disk)
diskdevs[${#diskdevs[@]}]="$next"; shift;;
--dry-run) DRY_RUN=true;;
--kvm) kvm="$next"; shift;;
-n|--netdev)
netdevs[${#netdevs[@]}]=$next; shift;;
-v|--verbose) VERBOSITY=$((${VERBOSITY}+1));;
--dowait) dowait=true;;
--no-dowait) dowait=false;;
--bios) bios="$next"; shift;;
--uefi) uefi=true;;
--uefi-nvram) uefi=true; uefi_nvram="$next"; shift;;
--) shift; break;;
esac
shift;
done
[ ${#netdevs[@]} -eq 0 ] && netdevs=( "${DEF_BRIDGE}" )
pt=( "$@" )
local kvm_pkg="" virtio_scsi_bus="virtio-scsi-pci" virtio_rng_device="virtio-rng-pci"
[ -n "$kvm" ] && kvm_pkg="none"
case $(uname -m) in
i?86)
[ -n "$kvm" ] ||
{ kvm="qemu-system-i386"; kvm_pkg="qemu-system-x86"; }
;;
x86_64)
[ -n "$kvm" ] ||
{ kvm="qemu-system-x86_64"; kvm_pkg="qemu-system-x86"; }
;;
s390x)
[ -n "$kvm" ] ||
{ kvm="qemu-system-s390x"; kvm_pkg="qemu-system-misc"; }
def_netmodel=${DEF_NETMODEL:-"virtio-net-ccw"}
# disable virtio-scsi-bus
virtio_scsi_bus="virtio-scsi-ccw"
virtio_blk_bus="virtio-blk-ccw"
virtio_rng_device="virtio-rng-ccw"
;;
ppc64*)
[ -n "$kvm" ] ||
{ kvm="qemu-system-ppc64"; kvm_pkg="qemu-system-ppc"; }
def_netmodel="virtio-net-pci"
# virtio seems functional on in 14.10, but might want scsi here
#def_diskif="scsi"
archopts=( "${archopts[@]}" -machine pseries,usb=off )
archopts=( "${archopts[@]}" -device spapr-vscsi )
;;
*) kvm=qemu-system-$(uname -m);;
esac
KVM="$kvm"
kvmcmd=( $kvm -enable-kvm )
local bios_opts=""
if [ -n "$bios" ] && $uefi; then
error "--uefi (or --uefi-nvram) is incompatible with --bios"
return 1
fi
get_bios_opts "$bios" "$uefi" "$uefi_nvram" ||
{ error "failed to get bios opts"; return 1; }
bios_opts=( "${_RET[@]}" )
local out="" fmt="" bus="" unit="" index="" serial="" driver="" devopts=""
local busorindex="" driveopts="" cur="" val="" file="" wwn=""
for((i=0;i<${#diskdevs[@]};i++)); do
cur=${diskdevs[$i]}
IFS=","; set -- $cur; IFS="$oifs"
driver=""
id=$(printf "disk%02d" "$i")
file=""
fmt=""
bus=""
unit=""
index=""
serial=""
wwn=""
for tok in "$@"; do
[ "${tok#*=}" = "${tok}" -a -f "${tok}" -a -z "$file" ] && file="$tok"
val=${tok#*=}
case "$tok" in
driver=*) driver=$val;;
if=virtio) driver=virtio-blk;;
if=scsi) driver=scsi-hd;;
if=pflash) driver=;;
if=sd|if=mtd|floppy) fail "do not know what to do with $tok on $cur";;
id=*) id=$val;;
file=*) file=$val;;
fmt=*|format=*) fmt=$val;;
serial=*) serial=$val;;
wwn=*) wwn=$val;;
bus=*) bus=$val;;
unit=*) unit=$val;;
index=*) index=$val;;
esac
done
[ -z "$file" ] && fail "did not read a file from $cur"
if [ -f "$file" -a -z "$fmt" ]; then
out=$(LANG=C qemu-img info "$file") &&
fmt=$(echo "$out" | awk '$0 ~ /^file format:/ { print $3 }') ||
{ error "failed to determine format of $file"; return 1; }
elif [ -z "$fmt" ]; then
fmt=raw
fi
if [ -z "$driver" ]; then
driver="$def_disk_driver"
fi
if [ -z "$serial" ]; then
# use filename as serial if not provided a wwn
if [ -n "$wwn" ]; then
serial="$wwn"
else
serial="${file##*/}"
fi
fi
# make sure we add either bus= or index=
if [ -n "$bus" -o "$unit" ] && [ -n "$index" ]; then
fail "bus and index cant be specified together: $cur"
elif [ -z "$bus" -a -z "$unit" -a -z "$index" ]; then
index=$i
elif [ -n "$bus" -a -z "$unit" ]; then
unit=$i
fi
busorindex="${bus:+bus=$bus,unit=$unit}${index:+index=${index}}"
diskopts="file=${file},id=$id,if=none,format=$fmt,$busorindex"
devopts="$driver,drive=$id${serial:+,serial=${serial}}"
for tok in "$@"; do
case "$tok" in
id=*|if=*|driver=*|$file|file=*) continue;;
fmt=*|format=*) continue;;
serial=*|bus=*|unit=*|index=*) continue;;
file.locking=*)
qemu_supports_file_locking || {
debug 2 "qemu has no file locking." \
"Dropping '$tok' from: $cur"
continue
};;
esac
isdevopt "$driver" "$tok" && devopts="${devopts},$tok" ||
diskopts="${diskopts},${tok}"
done
case $driver in
virtio-blk-ccw)
# disable scsi when using virtio-blk-ccw
devopts="${devopts},scsi=off";;
esac
diskargs=( "${diskargs[@]}" -drive "$diskopts" -device "$devopts" )
done
local mnics_vflag=""
for((i=0;i<${VERBOSITY}-1;i++)); do mnics_vflag="${mnics_vflag}v"; done
[ -n "$mnics_vflag" ] && mnics_vflag="-${mnics_vflag}"
# now go through and split out options
# -device virtio-net-pci,netdev=virtnet0,mac=52:54:31:15:63:02
# -netdev type=tap,id=virtnet0,vhost=on,script=/etc/kvm/kvm-ifup.br0,downscript=no
local netopts="" devopts="" id="" need_taps=0 model=""
local device_args netdev_args
device_args=( )
netdev_args=( )
connections=( )
for((i=0;i<${#netdevs[@]};i++)); do
id=$(printf "net%02d" "$i")
netopts="";
devopts=""
# mac=auto is 'unspecified' (let qemu assign one)
mac="auto"
#vhost="off"
IFS=","; set -- ${netdevs[$i]}; IFS="$oifs"
bridge=$1; shift;
if [ "$bridge" = "user" ]; then
netopts="type=user"
ntype="user"
connections[$i]="user"
else
need_taps=1
ntype="tap"
netopts="type=tap"
connections[$i]="$bridge"
fi
netopts="${netopts},id=$id"
[ "$ntype" = "tap" ] && netopts="${netopts},script=no,downscript=no"
model="${def_netmodel}"
for tok in "$@"; do
[ "${tok#model=}" = "${tok}" ] && continue
case "${tok#model=}" in
virtio) model=virtio-net-pci;;
*) model=${tok#model=};;
esac
done
for tok in "$@"; do
case "$tok" in
mac=*) mac="${tok#mac=}"; continue;;
macaddr=*) mac=${tok#macaddr=}; continue;;
model=*) continue;;
esac
isdevopt "$model" "$tok" && devopts="${devopts},$tok" ||
netopts="${netopts},${tok}"
done
devopts=${devopts#,}
netopts=${netopts#,}
if [ "$mac" != "auto" ]; then
[ "$mac" = "random" ] && randmac && mac="$_RET"
padmac "$mac" "$i"
devopts="${devopts:+${devopts},}mac=$_RET"
fi
devopts="$model,netdev=$id${devopts:+,${devopts}}"
#netopts="${netopts},vhost=${vhost}"
device_args[$i]="$devopts"
netdev_args[$i]="$netopts"
done
trap cleanup EXIT
reqs=( "$kvm" )
pkgs=( "$kvm_pkg" )
for((i=0;i<${#reqs[@]};i++)); do
req=${reqs[$i]}
pkg=${pkgs[$i]}
[ "$pkg" = "none" ] && continue
command -v "$req" >/dev/null || {
missing="${missing:+${missing} }${req}"
missing_pkgs="${missing_pkgs:+${missing_pkgs} }$pkg"
}
done
if [ -n "$missing" ]; then
local reply cmd=""
cmd=( sudo apt-get --quiet install ${missing_pkgs} )
error "missing prereqs: $missing";
error "install them now with the following?: ${cmd[*]}"
read reply && [ "$reply" = "y" -o "$reply" = "Y" ] ||
{ error "run: apt-get install ${missing_pkgs}"; return 1; }
"${cmd[@]}" || { error "failed to install packages"; return 1; }
fi
if [ $need_taps -ne 0 ]; then
local missing="" missing_pkgs="" reqs="" req="" pkgs="" pkg=""
for i in "${connections[@]}"; do
[ "$i" = "user" -o -e "/sys/class/net/$i" ] ||
missing="${missing} $i"
done
[ -z "$missing" ] || {
error "cannot create connection on: ${missing# }."
error "bridges do not exist.";
return 1;
}
error "creating tap devices: ${connections[*]}"
if $DRY_RUN; then
error "sudo $0 tap-control make-nics" \
$mnics_vflag "${connections[@]}"
taps=""
for((i=0;i<${#connections[@]};i++)); do
if [ "${connections[$i]}" = "user" ]; then
taps="${taps} skip"
else
taps="${taps} dryruntap$i:brctl"
fi
done
else
taps=$(sudo "$0" tap-control make-nics \
${mnics_vflag} "${connections[@]}") ||
{ error "$failed to make-nics ${connections[*]}"; return 1; }
fi
TAPDEVS=( ${taps} )
for((i=0;i<${#TAPDEVS[@]};i++)); do
cur=${TAPDEVS[$i]}
[ "${cur#*:}" = "ovs" ] || continue
conn=${connections[$i]}
OVS_CLEANUP[${#OVS_CLEANUP[@]}]="${conn}:${cur%:*}"
done
debug 2 "tapdevs='${TAPDEVS[@]}'"
[ ${#OVS_CLEANUP[@]} -eq 0 ] || error "OVS_CLEANUP='${OVS_CLEANUP[*]}'"
for((i=0;i<${#TAPDEVS[@]};i++)); do
cur=${TAPDEVS[$i]}
[ "$cur" = "skip" ] && continue
netdev_args[$i]="${netdev_args[$i]},ifname=${cur%:*}";
done
fi
netargs=()
for((i=0;i<${#device_args[@]};i++)); do
netargs=( "${netargs[@]}" -device "${device_args[$i]}"
-netdev "${netdev_args[$i]}")
done
local bus_devices
if [ -n "${virtio_scsi_bus}" ]; then
bus_devices=( -device "$virtio_scsi_bus,id=virtio-scsi-xkvm" )
fi
local rng_devices
rng_devices=( -object "rng-random,filename=/dev/urandom,id=objrng0"
-device "$virtio_rng_device,rng=objrng0,id=rng0" )
cmd=( "${kvmcmd[@]}" "${archopts[@]}"
"${bios_opts[@]}"
"${bus_devices[@]}"
"${rng_devices[@]}"
"${netargs[@]}"
"${diskargs[@]}" "${pt[@]}" )
local pcmd=$(quote_cmd "${cmd[@]}")
error "$pcmd"
${DRY_RUN} && return 0
if $dowait; then
"${cmd[@]}" &
KVM_PID=$!
debug 1 "kvm pid=$KVM_PID. my pid=$$"
wait
ret=$?
KVM_PID=""
else
"${cmd[@]}"
ret=$?
fi
return $ret
}
if [ "$1" = "tap-control" ]; then
shift
mode=$1
shift || fail "must give mode to tap-control"
case "$mode" in
make-nics) make_nics "$@";;
ovs-cleanup) ovs_cleanup "$@";;
*) fail "tap mode must be either make-nics or ovs-cleanup";;
esac
else
main "$@"
fi
# vi: ts=4 expandtab syntax=sh