Run OpenWrt on QEMU virtual machines with LAN and WAN network.

host-network-setup.sh

#
# The following script will
#   - Create Linux bridge $BR_WAN, $BR_LAN
#   - Install IP addresses and basic routes
#   - Enable proxy_arp on $BR_WAN
#   - Enable ip_forward
#   - Enable MASQUERADE on $IF_INET

# - $BR_LAN, $BR_WAN has to be allowed in ~/.usr/etc/qemu/bridge.conf
#
#	Sample content:
#
#		allow br-lan
#		allow br-wan
#
#	See qemu-bridge-helper.c of QEMU source code for details (`allow all`, `deny all`, `include xxx` can also be used).
#
# config variables
BR_WAN="br-wan"
BR_LAN="br-lan"
IF_INET="eth0"

# - qemu-bridge-help has to be root setuid program.
HELPER="$HOME/.usr/libexec/qemu-bridge-helper"
mac_rand() {
	hexdump -n 3 -e '"52:54:00:" 2/1 "%02x:" 1/1 "%02x"' /dev/urandom
}

# 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 dev "$BR_LAN"
sudo ip route add 192.168.1.0/24 dev "$BR_LAN"

# setup bridge for WAN network
sudo ip link add dev "$BR_WAN" type bridge
sudo ip addr add 192.168.7.1 dev "$BR_WAN"
sudo ip link set dev "$BR_WAN" up
#sudo ip link set dev tap0 master "$BR_WAN"
sudo ip route add 192.168.7.0/24 dev "$BR_WAN"

# Internet access setup
sudo sysctl -w net.ipv4.ip_forward=1
sudo sysctl -w net.ipv4.conf."$BR_WAN".proxy_arp=1
sudo iptables -t nat -A POSTROUTING -o "$IF_INET" -j MASQUERADE

openwrt-wan-setup.sh

openwrt_wan_static() {
  # Run this within OpenWrt
  uci batch <<EOF
  delete network.wan
  set network.wan=interface
  set network.wan.ifname=eth1
  set network.wan.proto=static
  set network.wan.ipaddr=192.168.7.2
  set network.wan.netmask=255.255.255.0
  set network.wan.gateway=192.168.7.1
  add_list network.wan.dns=208.67.222.222
  add_list network.wan.dns=208.67.220.220
  commit
  EOF
  /etc/init.d/network reload
}

host_dnsmasq_br_wan() {
  # Run this within host machine
  #
  #sudo apt-get install dnsmasq
  #sudo vi /etc/dnsmasq.conf
  #
  # Minimal conf.  The netmask is needed as br-wan is a bridge otherwise dnsmasq would complain "no address range available for DHCP request via br-wan"
  #
  #   interface=br-wan
  #   dhcp-range=192.168.7.50,192.168.7.150,255.255.255.0,30m
}

start-malta-instance.sh

MAC_LAN="$(mac_rand)"
MAC_WAN="$(mac_rand)"
qemu-system-mipsel -M malta -kernel bin/malta/openwrt-malta-le-vmlinux-initramfs.elf -nographic -m 128 \
	-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"

start-realview-instance.sh

# TODO
#
# 1. Network device
# 2. How to get a EL-flavour arm
# 3. How to get ARMv7 
#
MAC_LAN="$(mac_rand)"
MAC_WAN="$(mac_rand)"
IMG=bin/realview/openwrt-realview-vmlinux-initramfs.elf

qemu-system-arm -M realview-eb-mpcore -nographic -m 128 \
	-kernel "$IMG"

start-x86-{64,generic}-instance.sh

# SATA and IDE interface? https://dev.openwrt.org/ticket/17947
#
# This should work for both subtargets 64 and generic
MAC_LAN="$(mac_rand)"
MAC_WAN="$(mac_rand)"
IMG=bin/x86/openwrt-x86-64-combined-ext4.img
if [ ! -s "$IMG" -a -s "$IMG.gz" ]; then
	zcat "$IMG.gz" >"$IMG"
fi
package/system/procd/files/hotplug.json
qemu-system-x86_64 -nographic -m 128 \
	-netdev bridge,id=lan,br="$BR_LAN,helper=$HELPER" -device e1000,netdev=lan,mac="$MAC_LAN" \
	-netdev bridge,id=wan,br="$BR_WAN,helper=$HELPER" -device e1000,netdev=wan,mac="$MAC_WAN" \
	-device ich9-ahci,id=ahci \
	-device ide-drive,drive=drv0,bus=ahci.0 \
	-drive "file=$IMG,format=raw,id=drv0,if=none" \

start-x86-{64,kvm_guest}-instance.sh

# 64,kvm_guest uses virtio drivers
#
# - List network information with `info network`
# - Delete device with `device_del devlan`
# - Delete network interface from host system (e.g. tap devices) with `netdev_del lan`
#
# Add/del actions operate by id and default id's like 'virtio-net-pci.0' won't work as per QEMU 2.3.0.  See "qdev: Assign a default device ID when none is p" for details, https://lists.nongnu.org/archive/html/qemu-devel/2014-01/msg01013.html
#
#    From Paolo Bonzini
#    > Without the patch, how does a user unplug a device for which he didn't specify
#    > an ID (eg. forgotten, added quickly...)
#    He doesn't. :)
#
# OpenWrt kvm_guest image enables CONFIG_VIRTIO_BALLOON by default.
#
# - `-balloon` is an alias of `-device virtio-balloon-pci`
# - a guest kernel thread `[vballoon]` is responsible for the interaction
# - `info balloon` to see the current actual memory reserved
# - `balloon 32` to resize the memory to 32MB
# - `ballone 65` will only resize the memory to 64MB
#
# - QEMU Internals: vhost architecture, http://blog.vmsplice.net/2011/09/qemu-internals-vhost-architecture.html
# - VIRTIO AND VHOST_NET, https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Virtualization_Tuning_and_Optimization_Guide/sect-Virtualization_Tuning_Optimization_Guide-Networking-Virtio_and_vhostnet.html
MAC_LAN="$(mac_rand)"
MAC_WAN="$(mac_rand)"
#IMG=bin/x86/openwrt-x86-kvm_guest-combined-ext4.img
IMG=bin/x86/openwrt-x86-64-combined-ext4.img
if [ ! -s "$IMG" -a -s "$IMG.gz" ]; then
	zcat "$IMG.gz" >"$IMG"
fi
qemu-system-x86_64 -nographic -m 64 \
	-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=$IMG,format=raw,if=virtio" \
	-device virtio-balloon-pci \
	-chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 \
	-device virtio-serial \
	-device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0 \