1#!/vendor/bin/sh 2 3# Do all the setup required for WiFi. 4# The kernel driver mac80211_hwsim has already created two virtual wifi devices 5# us. These devices are connected so that everything that's sent on one device 6# is recieved on the other and vice versa. This allows us to create a fake 7# WiFi network with an access point running inside the guest. Here is the setup 8# for that and the basics of how it works. 9# 10# Create a namespace named router and move eth0 to it. Create a virtual ethernet 11# pair of devices and move both one virtual ethernet interface and one virtual 12# wifi interface into the router namespace. Then set up NAT networking for those 13# interfaces so that traffic flowing through them reach eth0 and eventually the 14# host and the internet. The main network namespace will now only see the other 15# ends of those pipes and send traffic on them depending on if WiFi or radio is 16# used. Finally run hostapd in the network namespace to create an access point 17# for the guest to connect to and dnsmasq to serve as a DHCP server for the WiFi 18# connection. 19# 20# main namespace router namespace 21# ------- ---------- | --------------- 22# | ril |<----->| radio0 |<--+--->| radio0-peer |<-------+ 23# ------- ---------- | --------------- | 24# | ^ | 25# | | | 26# | v v 27# | ************* -------- 28# | * ipv6proxy *<--->| eth0 |<--+ 29# | ************* -------- | 30# | ^ ^ | 31# | | | | 32# | v | | 33# ------------------ --------- | --------- | | 34# | wpa_supplicant |<->| wlan0 |<--+------->| wlan1 |<---------+ | 35# ------------------ --------- | --------- | 36# | ^ ^ | 37# | | | v 38# | v v -------- 39# | *********** *********** | host | 40# | * hostapd * * dnsmasq * -------- 41# | *********** *********** 42# 43 44NAMESPACE="router" 45rm -rf /data/vendor/var/run/netns/${NAMESPACE} 46rm -rf /data/vendor/var/run/netns/${NAMESPACE}.pid 47# We need to fake a mac address to pass CTS 48# And the kernel only accept mac addresses with some special format 49# (Like, begin with 02) 50/system/bin/ip link set dev wlan0 address 02:00:00:44:55:66 51 52createns ${NAMESPACE} 53# createns will have created a file that contains the process id (pid) of a 54# process running in the network namespace. This pid is needed for some commands 55# to access the namespace. 56PID=$(cat /data/vendor/var/run/netns/${NAMESPACE}.pid) 57/system/bin/ip link set eth0 netns ${PID} 58/system/bin/ip link add radio0 type veth peer name radio0-peer 59/system/bin/ip link set radio0-peer netns ${PID} 60# Enable privacy addresses for radio0, this is done by the framework for wlan0 61sysctl -wq net.ipv6.conf.radio0.use_tempaddr=2 62/system/bin/ip addr add 192.168.200.2/24 broadcast 192.168.200.255 dev radio0 63execns ${NAMESPACE} /system/bin/ip addr add 192.168.200.1/24 dev radio0-peer 64execns ${NAMESPACE} sysctl -wq net.ipv6.conf.all.forwarding=1 65execns ${NAMESPACE} /system/bin/ip link set radio0-peer up 66# Start the dhcp client for eth0 to acquire an address 67setprop ctl.start dhcpclient_rtr 68# Create iptables entries. -w will cause an indefinite wait for the exclusive 69# lock. Without this flag iptables can sporadically fail if something else is 70# modifying the iptables at the same time. -W indicates the number of micro- 71# seconds between each retry. The default is one second which seems like a long 72# time. Keep this short so we don't slow down startup too much. 73execns ${NAMESPACE} /system/bin/iptables -w -W 50000 -t nat -A POSTROUTING -s 192.168.232.0/21 -o eth0 -j MASQUERADE 74execns ${NAMESPACE} /system/bin/iptables -w -W 50000 -t nat -A POSTROUTING -s 192.168.200.0/24 -o eth0 -j MASQUERADE 75/system/bin/iw phy phy1 set netns $PID 76execns ${NAMESPACE} /system/bin/ip addr add 192.168.232.1/21 dev wlan1 77execns ${NAMESPACE} /system/bin/ip link set wlan1 up 78# Start the IPv6 proxy that will enable use of IPv6 in the main namespace 79setprop ctl.start ipv6proxy 80execns ${NAMESPACE} sysctl -wq net.ipv4.ip_forward=1 81# Start hostapd, the access point software 82setprop ctl.start emu_hostapd 83# Start DHCP server for the wifi interface 84setprop ctl.start dhcpserver 85/system/bin/ip link set radio0 up 86