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 44 NAMESPACE="router" 45 rm -rf /data/vendor/var/run/netns/${NAMESPACE} 46 rm -rf /data/vendor/var/run/netns/${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 52 createns ${NAMESPACE} 53 # createns will have created a file that contains the process id (pid) of a 54 # process running in the network namespace. This pid is needed for some commands 55 # to access the namespace. 56 PID=$(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 61 sysctl -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 63 execns ${NAMESPACE} /system/bin/ip addr add 192.168.200.1/24 dev radio0-peer 64 execns ${NAMESPACE} sysctl -wq net.ipv6.conf.all.forwarding=1 65 execns ${NAMESPACE} /system/bin/ip link set radio0-peer up 66 # Start the dhcp client for eth0 to acquire an address 67 setprop 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. 73 execns ${NAMESPACE} /system/bin/iptables -w -W 50000 -t nat -A POSTROUTING -s 192.168.232.0/21 -o eth0 -j MASQUERADE 74 execns ${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 76 execns ${NAMESPACE} /system/bin/ip addr add 192.168.232.1/21 dev wlan1 77 execns ${NAMESPACE} /system/bin/ip link set wlan1 up 78 # Start the IPv6 proxy that will enable use of IPv6 in the main namespace 79 setprop ctl.start ipv6proxy 80 execns ${NAMESPACE} sysctl -wq net.ipv4.ip_forward=1 81 # Start hostapd, the access point software 82 setprop ctl.start emu_hostapd 83 # Start DHCP server for the wifi interface 84 setprop ctl.start dhcpserver 85 /system/bin/ip link set radio0 up 86
