OpenWrt – Rev 4
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#!/usr/bin/env bash
SELF="$0"
# Linux bridge for connecting lan and wan network of guest machines
BR_LAN="${BR_LAN:-br-lan}"
BR_WAN="${BR_WAN:-br-wan}"
# Host network interface providing internet access for guest machines
IF_INET="${IF_INET:-eth0}"
# qemu-bridge-helper does two things here
#
# - create tap interface
# - add the tap interface to bridge
#
# as such it requires CAP_NET_ADMIN to do its job. It will be convenient to
# have it as a root setuid program. Be aware of the security risks implied
#
# the helper has an acl list which defaults to deny all bridge. we need to add
# $BR_LAN and $BR_WAN to its allow list
#
# # sudo vim /etc/qemu/bridge.conf
# allow br-lan
# allow br-wan
#
# Other allowed directives can be 'allow all', 'deny all', 'include xxx', See
# qemu-bridge-helper.c of qemu source code for details.
#
# The helper can be provided by package qemu-system-common on debian, or
# qemu-kvm-common on rhel
#
HELPER="${HELPER:-/usr/libexec/qemu-bridge-helper}"
### end of global settings
__errmsg() {
echo "$*" >&2
}
do_setup() {
# setup bridge for LAN network
sudo ip link add dev "$BR_LAN" type bridge
sudo ip link set dev "$BR_LAN" up
sudo ip addr add 192.168.1.3/24 dev "$BR_LAN"
# setup bridge for WAN network
#
# minimal dnsmasq config for configuring guest wan network with dhcp
#
# # sudo apt-get install dnsmasq
# # sudo vi /etc/dnsmasq.conf
# interface=br-wan
# dhcp-range=192.168.7.50,192.168.7.150,255.255.255.0,30m
#
sudo ip link add dev "$BR_WAN" type bridge
sudo ip link set dev "$BR_WAN" up
sudo ip addr add 192.168.7.1/24 dev "$BR_WAN"
# guest internet access
sudo sysctl -w "net.ipv4.ip_forward=1"
sudo sysctl -w "net.ipv4.conf.$BR_WAN.proxy_arp=1"
while sudo iptables -t nat -D POSTROUTING -o "$IF_INET" -j MASQUERADE 2>/dev/null; do true; done
sudo iptables -t nat -A POSTROUTING -o "$IF_INET" -j MASQUERADE
}
check_setup_() {
ip link show "$BR_LAN" >/dev/null || return 1
ip link show "$BR_WAN" >/dev/null || return 1
[ -x "$HELPER" ] || {
__errmsg "helper $HELPER is not an executable"
return 1
}
}
check_setup() {
check_setup_ || {
__errmsg "please check the script content to see the environment requirement"
return 1
}
}
#do_setup; check_setup; exit $?
usage() {
cat >&2 <<EOF
Usage: $SELF [-h|--help]
$SELF <target>
[<subtarget> [<extra-qemu-options>]]
[--kernel <kernel>]
[--rootfs <rootfs>]
<subtarget> will default to "generic" and must be specified if
<extra-qemu-options> are present
e.g. <subtarget> for malta can be le, be, le64, be64, le-glibc, le64-glibc, etc
<kernel>, <rootfs> can be required or optional arguments to qemu depending on
the actual <target> in use. They will default to files under bin/targets/
Examples
$SELF x86 64
$SELF x86 64 -enable-kvm -device virtio-balloon-pci
$SELF x86 64 -incoming tcp:0:4444
$SELF x86 64-glibc
$SELF malta be -m 64
$SELF malta le64
$SELF malta be-glibc
$SELF armvirt 32 \\
--kernel bin/targets/armvirt/32/openwrt-armvirt-32-zImage \\
--rootfs bin/targets/armvirt/32/openwrt-armvirt-32-root.ext4
EOF
}
rand_mac() {
hexdump -n 3 -e '"52:54:00:" 2/1 "%02x:" 1/1 "%02x"' /dev/urandom
}
parse_args() {
o_qemu_extra=()
while [ "$#" -gt 0 ]; do
case "$1" in
--kernel) o_kernel="$2"; shift 2 ;;
--rootfs) o_rootfs="$2"; shift 2 ;;
--help|-h)
usage
exit 0
;;
*)
if [ -z "$o_target" ]; then
o_target="$1"
elif [ -z "$o_subtarget" ]; then
o_subtarget="$1"
else
o_qemu_extra+=("$1")
fi
shift
;;
esac
done
MAC_LAN="$(rand_mac)"
MAC_WAN="$(rand_mac)"
[ -n "$o_target" ] || {
usage
return 1
}
[ -n "$o_subtarget" ] || o_subtarget="generic"
o_bindir="bin/targets/$o_target/$o_subtarget"
}
start_qemu_armvirt() {
local kernel="$o_kernel"
local rootfs="$o_rootfs"
local cpu
local qemu_exe
case "${o_subtarget%-*}" in
32)
qemu_exe="qemu-system-arm"
cpu="cortex-a15"
[ -n "$kernel" ] || kernel="$o_bindir/openwrt-$o_target-${o_subtarget%-*}-zImage-initramfs"
;;
64)
qemu_exe="qemu-system-aarch64"
cpu="cortex-a57"
[ -n "$kernel" ] || kernel="$o_bindir/openwrt-$o_target-${o_subtarget%-*}-Image-initramfs"
;;
*)
__errmsg "target $o_target: unknown subtarget $o_subtarget"
return 1
;;
esac
[ -z "$rootfs" ] || {
if [ ! -f "$rootfs" -a -s "$rootfs.gz" ]; then
gunzip "$rootfs.gz"
fi
o_qemu_extra+=( \
"-drive" "file=$rootfs,format=raw,if=virtio" \
"-append" "root=/dev/vda rootwait" \
)
}
"$qemu_exe" -machine virt -cpu "$cpu" -nographic \
-netdev bridge,id=lan,br="$BR_LAN,helper=$HELPER" -device virtio-net-pci,id=devlan,netdev=lan,mac="$MAC_LAN" \
-netdev bridge,id=wan,br="$BR_WAN,helper=$HELPER" -device virtio-net-pci,id=devwan,netdev=wan,mac="$MAC_WAN" \
-kernel "$kernel" \
"${o_qemu_extra[@]}"
}
start_qemu_malta() {
local is64
local isel
local qemu_exe
local kernel="$o_kernel"
# o_subtarget can be le, be, le64, be64, le-glibc, le64-glibc, etc..
is64="$(echo $o_subtarget | grep -o 64)"
[ "$(echo "$o_subtarget" | grep -o '^..')" = "le" ] && isel="el"
qemu_exe="qemu-system-mips$is64$isel"
[ -n "$kernel" ] || kernel="$o_bindir/openwrt-malta-${o_subtarget%-*}-vmlinux-initramfs.elf"
# NOTE: order of wan, lan -device arguments matters as it will affect which
# one will be actually used as the wan, lan network interface inside the
# guest machine
"$qemu_exe" -machine malta -nographic \
-netdev bridge,id=wan,br="$BR_WAN,helper=$HELPER" -device pcnet,netdev=wan,mac="$MAC_WAN" \
-netdev bridge,id=lan,br="$BR_LAN,helper=$HELPER" -device pcnet,netdev=lan,mac="$MAC_LAN" \
-kernel "$kernel" \
"${o_qemu_extra[@]}"
}
start_qemu_x86() {
local rootfs="$o_rootfs"
local qemu_exe
[ -n "$rootfs" ] || {
rootfs="$o_bindir/openwrt-$o_target-${o_subtarget%-*}-combined-ext4.img"
if [ ! -f "$rootfs" -a -s "$rootfs.gz" ]; then
gunzip "$rootfs.gz"
fi
}
#
# generic: 32-bit, pentium4 (CONFIG_MPENTIUM4), kvm guest, virtio
# legacy: 32-bit, i486 (CONFIG_M486)
# 64: 64-bit, kvm guest, virtio
#
case "${o_subtarget%-*}" in
legacy) qemu_exe="qemu-system-i386" ;;
generic|64) qemu_exe="qemu-system-x86_64" ;;
*)
__errmsg "target $o_target: unknown subtarget $o_subtarget"
return 1
;;
esac
case "${o_subtarget%-*}" in
legacy)
# use IDE (PATA) disk instead of AHCI (SATA). Refer to link
# [1] for related discussions
#
# To use AHCI interface
#
# -device ich9-ahci,id=ahci \
# -device ide-drive,drive=drv0,bus=ahci.0 \
# -drive "file=$rootfs,format=raw,id=drv0,if=none" \
#
# [1] https://dev.openwrt.org/ticket/17947
"$qemu_exe" -nographic \
-netdev bridge,id=lan,br="$BR_LAN,helper=$HELPER" -device e1000,id=devlan,netdev=lan,mac="$MAC_LAN" \
-netdev bridge,id=wan,br="$BR_WAN,helper=$HELPER" -device e1000,id=devwan,netdev=wan,mac="$MAC_WAN" \
-device ide-drive,drive=drv0 \
-drive "file=$rootfs,format=raw,id=drv0,if=none" \
"${o_qemu_extra[@]}"
;;
generic|64)
"$qemu_exe" -nographic \
-netdev bridge,id=lan,br="$BR_LAN,helper=$HELPER" -device virtio-net-pci,id=devlan,netdev=lan,mac="$MAC_LAN" \
-netdev bridge,id=wan,br="$BR_WAN,helper=$HELPER" -device virtio-net-pci,id=devwan,netdev=wan,mac="$MAC_WAN" \
-drive "file=$rootfs,format=raw,if=virtio" \
"${o_qemu_extra[@]}"
;;
esac
}
start_qemu() {
case "$o_target" in
armvirt) start_qemu_armvirt ;;
malta) start_qemu_malta ;;
x86) start_qemu_x86 ;;
*)
__errmsg "target $o_target is not supported yet"
return 1
;;
esac
}
check_setup \
&& parse_args "$@" \
&& start_qemu