10df4ca4dSimoerman# openwifi 22ee67178SXianjun Jiao<img src="./openwifi-arch.jpg" width="900"> 32ee67178SXianjun Jiao 4*38f76c01SJiao Xianjun**openwifi:** Linux mac80211 compatible full-stack IEEE802.11/Wi-Fi design based on SDR (Software Defined Radio). 52ee67178SXianjun Jiao 6eb247655SJiao XianjunThis repository includes Linux driver and software. [openwifi-hw](https://github.com/open-sdr/openwifi-hw) repository has the FPGA design. [[Detailed architecture](https://github.com/open-sdr/openwifi/tree/master/doc)] 72ee67178SXianjun Jiao 8a766ca29SJiao Xianjun[Demo [video](https://youtu.be/NpjEaszd5u4). Video [download](https://users.ugent.be/~xjiao/openwifi-low-aac.mp4)] [openwifi [maillist](https://lists.ugent.be/wws/subscribe/openwifi)] 92ee67178SXianjun Jiao 102ee67178SXianjun JiaoOpenwifi code has dual licenses. AGPLv3 is the opensource license. For non-opensource license, please contact [email protected]. Openwifi project also leverages some 3rd party modules. It is your duty to check and follow licenses of those modules according to your purpose. You can find [an example explanation from Analog Devices](https://github.com/analogdevicesinc/hdl/blob/master/LICENSE) for this compound license conditions. 112ee67178SXianjun Jiao 122ee67178SXianjun JiaoOpenwifi was born in [ORCA project](https://www.orca-project.eu/) (EU's Horizon2020 programme under agreement number 732174). 132ee67178SXianjun Jiao 142ee67178SXianjun Jiao**Features:** 152ee67178SXianjun Jiao 16a20313b8SJiao Xianjun* 802.11a/g 17a20313b8SJiao Xianjun* 802.11n MCS 0~7 (Only PHY rx for now. Full system support of 802.11n will come soon) 18a20313b8SJiao Xianjun* 20MHz bandwidth; 70 MHz to 6 GHz frequency range 192ee67178SXianjun Jiao* Mode tested: Ad-hoc; Station; AP 20836d8a87SJiao Xianjun* DCF (CSMA/CA) low MAC layer in FPGA (10us SIFS is achieved) 212ee67178SXianjun Jiao* Configurable channel access priority parameters: 222ee67178SXianjun Jiao * duration of RTS/CTS, CTS-to-self 232ee67178SXianjun Jiao * SIFS/DIFS/xIFS/slot-time/CW/etc 242ee67178SXianjun Jiao* Time slicing based on MAC address 252ee67178SXianjun Jiao* Easy to change bandwidth and frequency: 262ee67178SXianjun Jiao * 2MHz for 802.11ah in sub-GHz 272ee67178SXianjun Jiao * 10MHz for 802.11p/vehicle in 5.9GHz 282ee67178SXianjun Jiao* On roadmap: **802.11ax** 292ee67178SXianjun Jiao 302ee67178SXianjun Jiao**Performance (AP: openwifi at channel 44, client: TL-WDN4200 N900 Wireless Dual Band USB Adapter. iperf test):** 312ee67178SXianjun Jiao* AP --> client: 30.6Mbps(TCP), 38.8Mbps(UDP) 322ee67178SXianjun Jiao* client --> AP: 17.0Mbps(TCP), 21.5Mbps(UDP) 332ee67178SXianjun Jiao 342ee67178SXianjun Jiao**Supported SDR platforms:** 352ee67178SXianjun Jiao 3686bab9c1SJiao Xianjun* zc706 (Xilinx) + fmcomms2/fmcomms4 (Analog Devices) 372ee67178SXianjun Jiao* On roadmap: ADRV9361-Z7035/ADRV9364-Z7020 + ADRV1CRR-BOB (Analog Devices) 3886bab9c1SJiao Xianjun* On roadmap: zcu102 (Xilinx) + fmcomms2/fmcomms4/ADRV9371 (Analog Devices) 392ee67178SXianjun Jiao* Don't have any boards? Or you like JTAG boot instead of SD card? Check our test bed [w-iLab.t](https://doc.ilabt.imec.be/ilabt/wilab/tutorials/openwifi.html) tutorial. 402ee67178SXianjun Jiao 412ee67178SXianjun Jiao**Quick start:** (Example instructions are verified on Ubuntu 16/18) 422ee67178SXianjun Jiao 43eb247655SJiao Xianjun* Download pre-built [openwifi Linux img file](https://users.ugent.be/~xjiao/openwifi-1.0.0-ghent.zip). Burn the img file to a 16G SD card: 442ee67178SXianjun Jiao 452ee67178SXianjun Jiao``` 4686bab9c1SJiao Xianjunsudo dd bs=4M if=openwifi-1.0.0-ghent.img of=/dev/mmcblk0 472ee67178SXianjun Jiao(mmcblk0 is the dev name of sdcard in Linux. Make sure you use the correct one in your situation!) 482ee67178SXianjun Jiao(Above command takes a while) 492ee67178SXianjun Jiao``` 5086bab9c1SJiao Xianjun* Connect RX/TX antenna to RX1A/TX2A ports of your zc706+fmcomms2 platform, and make two antennas orthogonal to each other for good isolation. Config zc706 to SD card boot mode by switches (Read zc706 board spec on internet). Insert the SD card to zc706. (For fmcomms4/ad9364, you may connect antennas to TXA/RXA) 512ee67178SXianjun Jiao 522ee67178SXianjun Jiao* Connect the board to PC. (PC IP address should be 192.168.10.1). Power on the board. Then from PC: 532ee67178SXianjun Jiao 542ee67178SXianjun Jiao``` 552ee67178SXianjun Jiaossh [email protected] 562ee67178SXianjun Jiao(password: openwifi) 572ee67178SXianjun Jiaocd openwifi 582ee67178SXianjun Jiaoservice network-manager stop 592ee67178SXianjun Jiao./wgd.sh 6086bab9c1SJiao Xianjun(For fmcomms4, you need an extra command: ./set_ant.sh rx1 tx1) 612ee67178SXianjun Jiaoifconfig sdr0 up 622ee67178SXianjun Jiaoiwlist sdr0 scan 632ee67178SXianjun Jiao(you should see the Wi-Fi scan result) 642ee67178SXianjun Jiao``` 6586bab9c1SJiao Xianjun* Setup openwifi hotspot over topology: client -- (sdr0)|board|(eth0) -- (***ethX***)|PC|(***ethY***) -- internet 6686bab9c1SJiao Xianjun * Enable IPv4 **IP forwarding** on both **board** and **PC** 672ee67178SXianjun Jiao * Then, on board: 682ee67178SXianjun Jiao 692ee67178SXianjun Jiao ifconfig sdr0 192.168.13.1 702ee67178SXianjun Jiao route add default gw 192.168.10.1 712ee67178SXianjun Jiao service isc-dhcp-server restart 722ee67178SXianjun Jiao hostapd hostapd-openwifi.conf 732ee67178SXianjun Jiao * Then, on PC: 742ee67178SXianjun Jiao 752ee67178SXianjun Jiao sudo iptables -t nat -A POSTROUTING -o ethY -j MASQUERADE 762ee67178SXianjun Jiao sudo ip route add 192.168.13.0/24 via 192.168.10.122 dev ethX 772ee67178SXianjun Jiao * Now you can connect openwifi by your devices (phone, laptop, etc) 782ee67178SXianjun Jiao* Connect openwifi to another hotspot. Terminate hostapd, edit wpa-connect.conf properly, then: 792ee67178SXianjun Jiao 802ee67178SXianjun Jiao ./wgd.sh 8186bab9c1SJiao Xianjun (For fmcomms4, you need an extra command: ./set_ant.sh rx1 tx1) 822ee67178SXianjun Jiao route del default gw 192.168.10.1 832ee67178SXianjun Jiao wpa_supplicant -i sdr0 -c wpa-connect.conf 842ee67178SXianjun Jiao (Wait for connection done, then open another ssh terminal) 852ee67178SXianjun Jiao dhclient sdr0 86da62eb45SJiao Xianjun (Wait for its done, then you should have connection) 872ee67178SXianjun Jiao 882ee67178SXianjun Jiao* ***Note***: If openwifi stops working after ~2 hours, it means the evaluation license of Xilinx Viterbi decoder has expired. You need to power cycle the board. Run this command several times on board to confirm: 892ee67178SXianjun Jiao 902ee67178SXianjun Jiao root@analog:~/openwifi# ./sdrctl dev sdr0 get reg rx 20 912ee67178SXianjun Jiao SENDaddr: 00040050 922ee67178SXianjun Jiao reg val: 34be0123 932ee67178SXianjun Jiao (If the last number of reg val is always 3, that means the Viterbi decoder stops working) 94eb247655SJiao Xianjun* Real-time control/config via sdrctl (time slice config, etc), please go to openwifi/doc. 952ee67178SXianjun Jiao 962ee67178SXianjun Jiao**Build openwifi Linux img based on openwifi FPGA and driver:** 972ee67178SXianjun Jiao 985ae382e0SJiao Xianjun* Install Vivado/SDK 2017.4.1 (If you don't need to re-compile FPGA, WebPack version without license is enough) 995ae382e0SJiao Xianjun* Get pre-built FPGA files from openwifi-hw repository. 1002ee67178SXianjun Jiao 1012ee67178SXianjun Jiao``` 1022ee67178SXianjun Jiaogit submodule init openwifi-hw 1032ee67178SXianjun Jiaogit submodule update openwifi-hw 1042ee67178SXianjun Jiaocd openwifi-hw 10596be0adbSJiao Xianjungit checkout master 1062ee67178SXianjun Jiaogit pull 1072ee67178SXianjun Jiao``` 1082ee67178SXianjun Jiao* Build Linux kernel and modules: 1092ee67178SXianjun Jiao 1102ee67178SXianjun Jiao``` 1112ee67178SXianjun Jiaoexport XILINX_DIR=your_Xilinx_directory 1122ee67178SXianjun Jiaocd openwifi 1132ee67178SXianjun Jiaogit submodule init adi-linux 1142ee67178SXianjun Jiaogit submodule update adi-linux 1152ee67178SXianjun Jiao(Will take a while) 1162ee67178SXianjun Jiaocd adi-linux 1172ee67178SXianjun Jiaogit reset --hard 4220d5d24c6c7589fc702db4f941f0632b5ad767 1182ee67178SXianjun Jiaocp ../kernel_boot/kernel_config ./.config 1192ee67178SXianjun Jiaosource $XILINX_DIR/SDK/2017.4/settings64.sh 1202ee67178SXianjun Jiaoexport ARCH=arm 1212ee67178SXianjun Jiaoexport CROSS_COMPILE=arm-linux-gnueabihf- 1222ee67178SXianjun Jiaomake -j12 UIMAGE_LOADADDR=0x8000 uImage 1232ee67178SXianjun Jiao(Answer "y" to Xilinx DMA Engines (XILINX_DMA_ENGINES) [N/y/?] (NEW)) 1242ee67178SXianjun Jiaomake modules 1252ee67178SXianjun Jiao``` 1262ee67178SXianjun Jiao* Build openwifi Linux driver modules: 1272ee67178SXianjun Jiao 1282ee67178SXianjun Jiao``` 1292ee67178SXianjun Jiaoexport OPENWIFI_DIR=your_openwifi_directory 1302ee67178SXianjun Jiaocd $OPENWIFI_DIR/driver 1312ee67178SXianjun Jiao./make_all.sh $XILINX_DIR/SDK/2017.4/ $OPENWIFI_DIR/adi-linux/ 1322ee67178SXianjun Jiao``` 1332ee67178SXianjun Jiao* Build openwifi Linux devicetree: 1342ee67178SXianjun Jiao 1352ee67178SXianjun Jiao``` 1362ee67178SXianjun Jiaocd $OPENWIFI_DIR/kernel_boot 1372ee67178SXianjun Jiaodtc -I dts -O dtb -o devicetree.dtb devicetree.dts 1382ee67178SXianjun Jiao``` 1392ee67178SXianjun Jiao* Build openwifi BOOT.BIN based on FPGA files generated in openwifi-hw: 1402ee67178SXianjun Jiao 1412ee67178SXianjun Jiao``` 1422ee67178SXianjun Jiaocd $OPENWIFI_DIR/kernel_boot 143c017e305SJiao Xianjunsource $XILINX_DIR/SDK/2017.4/settings64.sh 1442ee67178SXianjun Jiao./build_boot_bin.sh ../openwifi-hw/zc706_fmcs2/sdk/system_top_hw_platform_0/system.hdf u-boot-zc70x.elf 1452ee67178SXianjun Jiao(u-boot-zc70x.elf is included in the original Analog Devices Linux img) 1462ee67178SXianjun Jiao``` 1472ee67178SXianjun Jiao* Download [2017_R1-2018_01_29.img.xz](http://swdownloads.analog.com/cse/2017_R1-2018_01_29.img.xz) from [Analog Devices Wiki](https://wiki.analog.com/resources/tools-software/linux-software/zynq_images). Burn it into a SD card via your PC. 1489e8d5e4aSJiao Xianjun* Mount SD card BOOT/rootfs partitions to SDCARD_DIR directory of your PC (If it is mounted automatically, find the directory). Then copy built files to SD card via your PC. (You can also update files over ftp/ssh after your full system runs. Please check next section. Read carefully user_space/sdcard_boot_update.sh and set your ftp root directory to $OPENWIFI_DIR in your PC): 1492ee67178SXianjun Jiao 1502ee67178SXianjun Jiao``` 1512ee67178SXianjun Jiaoexport SDCARD_DIR=sdcard_mount_point 1522ee67178SXianjun Jiaocp $OPENWIFI_DIR/kernel_boot/devicetree.dtb $SDCARD_DIR/BOOT 1532ee67178SXianjun Jiaocp $OPENWIFI_DIR/kernel_boot/output_boot_bin/BOOT.BIN $SDCARD_DIR/BOOT 1542ee67178SXianjun Jiaocp $OPENWIFI_DIR/adi-linux/arch/arm/boot/uImage $SDCARD_DIR/BOOT 1552ee67178SXianjun Jiaocd $SDCARD_DIR/BOOT 1562ee67178SXianjun Jiaosync 1572ee67178SXianjun Jiao 1582ee67178SXianjun Jiaosudo mkdir $SDCARD_DIR/rootfs/root/openwifi 1592ee67178SXianjun Jiaosudo find $OPENWIFI_DIR/driver -name \*.ko -exec cp {} $SDCARD_DIR/rootfs/root/openwifi/ \; 1602ee67178SXianjun Jiaosudo cp $OPENWIFI_DIR/user_space/* $SDCARD_DIR/rootfs/root/openwifi/ 1612ee67178SXianjun Jiao 1622ee67178SXianjun Jiaosudo mkdir $SDCARD_DIR/rootfs/lib/modules 1632ee67178SXianjun Jiaosudo mkdir $SDCARD_DIR/rootfs/lib/modules/4.14.0-g4220d5d24c6c 1642ee67178SXianjun Jiaosudo find $OPENWIFI_DIR/adi-linux -name \*.ko -exec cp {} $SDCARD_DIR/rootfs/lib/modules/4.14.0-g4220d5d24c6c/ \; 1652ee67178SXianjun Jiaosudo rm $SDCARD_DIR/rootfs/lib/modules/4.14.0-g4220d5d24c6c/{axidmatest.ko,xilinx_dma.ko,adi_axi_hdmi.ko,ad9361_drv.ko} -f 1662ee67178SXianjun Jiao 1672ee67178SXianjun Jiaosudo rm $SDCARD_DIR/rootfs/etc/udev/rules.d/70-persistent-net.rules 1682ee67178SXianjun Jiaosudo cp $OPENWIFI_DIR/kernel_boot/70-persistent-net.rules $SDCARD_DIR/rootfs/etc/udev/rules.d/ 1692ee67178SXianjun Jiao(Above rule will auto-rename wlan0 to sdr0 which is the openwifi NIC name) 1702ee67178SXianjun Jiaocd $SDCARD_DIR/rootfs 1712ee67178SXianjun Jiaosync 1722ee67178SXianjun Jiao``` 1732ee67178SXianjun Jiao**Run Linux and do some post-config:** 1742ee67178SXianjun Jiao 1752ee67178SXianjun Jiao* Insert the SD card to the board, power on and run serial console (such as minicom) from a PC via USB-UART cable to the board. After booting completes, in the PC serial console: 1762ee67178SXianjun Jiao 1772ee67178SXianjun Jiao``` 1782ee67178SXianjun Jiaoln -s /lib/modules/4.14.0-g4220d5d24c6c /lib/modules/4.14.0-g4220d5d 1792ee67178SXianjun Jiao(in case some Linux use short hash) 1802ee67178SXianjun Jiaodepmod 1812ee67178SXianjun Jiao(Ignore the error messages) 1822ee67178SXianjun Jiaomodprobe mac80211 1832ee67178SXianjun Jiaocd openwifi 1842ee67178SXianjun Jiao./wgd.sh 18586bab9c1SJiao Xianjun(For fmcomms4, you need an extra command: ./set_ant.sh rx1 tx1) 1862ee67178SXianjun Jiao(Wait for the completion) 1872ee67178SXianjun Jiaoifconfig 1882ee67178SXianjun Jiao(You should see sdr0 interface) 1892ee67178SXianjun Jiaoiwlist sdr0 scan 1902ee67178SXianjun Jiao(You should see the Wi-Fi scan results) 1912ee67178SXianjun Jiao``` 1922ee67178SXianjun Jiao* Config ssh server and ethernet IP address of the board. In the PC serial console: 1932ee67178SXianjun Jiao 1942ee67178SXianjun Jiao``` 1952ee67178SXianjun Jiaopasswd 1962ee67178SXianjun Jiao(ssh server needs a password, such as "openwifi") 1972ee67178SXianjun JiaoAdd "UseDNS no" to /etc/ssh/sshd_config, otherwise ssh login takes too long time 1982ee67178SXianjun JiaoSet static IP to board (If you have DHCP server on PC, you can skip this step) 1992ee67178SXianjun JiaoAdd following content to /etc/network/interfaces 2002ee67178SXianjun Jiao auto lo eth0 2012ee67178SXianjun Jiao iface lo inet loopback 2022ee67178SXianjun Jiao iface eth0 inet static 2032ee67178SXianjun Jiao address 192.168.10.122 2042ee67178SXianjun Jiao netmask 255.255.255.0 2052ee67178SXianjun JiaoAdd following content to /etc/resolv.conf 2062ee67178SXianjun Jiao nameserver 8.8.8.8 2072ee67178SXianjun Jiao nameserver 4.4.4.4 2082ee67178SXianjun Jiao 2092ee67178SXianjun JiaoDisable update (long time hang) on boot or ssh session: 2102ee67178SXianjun Jiao sudo chmod -x /etc/update-motd.d/90-updates-available 2112ee67178SXianjun Jiao sudo chmod -x /etc/update-motd.d/91-release-upgrade 2122ee67178SXianjun Jiao 2139e8d5e4aSJiao Xianjunreboot the board, and set proper IP (192.168.10.1) of the connected PC, then from the PC: 2142ee67178SXianjun Jiaossh [email protected] 2152ee67178SXianjun Jiao(password: openwifi) 2162ee67178SXianjun Jiao``` 2179e8d5e4aSJiao Xianjun* Make on board file update easier: 2189e8d5e4aSJiao Xianjun * Option 1: Access the board disk/rootfs from Ubuntu PC: "File manager --> Connect to Server...", input: sftp://[email protected]/root . Then you can operate files on board like normal files on your disk. To update files that need to be in boot partition (BOOT.BIN, uImage and devicetree.dtb), you can transfer those files to rootfs firstly, then on board: 2199e8d5e4aSJiao Xianjun 2209e8d5e4aSJiao Xianjun mount /dev/mmcblk0p1 /sdcard 2219e8d5e4aSJiao Xianjun (Create /sdcard directory firstly if it doesn't exist) 2229e8d5e4aSJiao Xianjun cp file /sdcard 2239e8d5e4aSJiao Xianjun cd /sdcard 2249e8d5e4aSJiao Xianjun sync 2259e8d5e4aSJiao Xianjun cd / 2269e8d5e4aSJiao Xianjun umount /sdcard 2279e8d5e4aSJiao Xianjun (Remember to power cycle the board) 2289e8d5e4aSJiao Xianjun * Option 2: Setup [ftp server](https://help.ubuntu.com/lts/serverguide/ftp-server.html) on PC, allow anonymous and change ftp root directory to $OPENWIFI_DIR. Then on board: 2299e8d5e4aSJiao Xianjun 2309e8d5e4aSJiao Xianjun ./sdcard_boot_update.sh 2319e8d5e4aSJiao Xianjun (Above command downloads uImage, BOOT.BIN and devicetree.dtb, then copy them into boot partition. Remember to power cycle) 2329e8d5e4aSJiao Xianjun ./wgd.sh remote 2339e8d5e4aSJiao Xianjun (Above command downloads driver files, and brings up sdr0) 23486bab9c1SJiao Xianjun (For fmcomms4, you need an extra command: ./set_ant.sh rx1 tx1) 2359e8d5e4aSJiao Xianjun 23686bab9c1SJiao Xianjun**Compile sdrctl on the board** ("On the board" means that you login to the board via ssh) 2372ee67178SXianjun Jiao 2382ee67178SXianjun Jiao``` 2392ee67178SXianjun Jiaosudo apt-get install libnl-3-dev 2402ee67178SXianjun Jiaosudo apt-get install libnl-genl-3-dev 241ffe9541bSJiao Xianjun(Please find the next section to see how to connect board to the internet via your PC) 2422ee67178SXianjun Jiao(or find out .deb files by above commands and copy .deb to the board, if you do not have internet) 2432ee67178SXianjun Jiao 24486bab9c1SJiao Xianjuncopy $OPENWIFI_DIR/user_space/sdrctl_src to the board, then on the board: 2452ee67178SXianjun Jiaocd sdrctl_src 2462ee67178SXianjun Jiaochmod +x version.sh 2472ee67178SXianjun Jiaomake 2482ee67178SXianjun Jiao``` 2492ee67178SXianjun Jiao**Internet config** 25086bab9c1SJiao Xianjun* Connect board to internet. Topology: board|(eth0) -- (***ethX***)|PC|(***ethY***) -- internet 25186bab9c1SJiao Xianjun * Enable IPv4 **IP forwarding** on both **board** and **PC** 25286bab9c1SJiao Xianjun * On board: 25386bab9c1SJiao Xianjun ``` 25486bab9c1SJiao Xianjun route add default gw 192.168.10.1 25586bab9c1SJiao Xianjun ``` 2562ee67178SXianjun Jiao * On PC. After this your board should have internet via NAT through your PC. 2572ee67178SXianjun Jiao 2582ee67178SXianjun Jiao ``` 2592ee67178SXianjun Jiao sudo iptables -t nat -A POSTROUTING -o ethY -j MASQUERADE 2602ee67178SXianjun Jiao ``` 26186bab9c1SJiao Xianjun* Setup AP for Wi-Fi client. Topology: client -- (sdr0)|board|(eth0) -- (***ethX***)|PC|(***ethY***) -- internet 2622ee67178SXianjun Jiao * On board: Install dhcp server preparing for serving your openwifi clients via hostapd. 2632ee67178SXianjun Jiao 2642ee67178SXianjun Jiao ``` 2652ee67178SXianjun Jiao sudo apt-get install isc-dhcp-server 2662ee67178SXianjun Jiao sudo apt-get install Haveged 26786bab9c1SJiao Xianjun sudo apt-get install hostapd 2682ee67178SXianjun Jiao ``` 2692ee67178SXianjun Jiao * Put user_space/dhcpd.conf into (overwrite) /etc/dhcp/dhcpd.conf on board. 2702ee67178SXianjun Jiao * On board: 2712ee67178SXianjun Jiao 2722ee67178SXianjun Jiao ``` 2732ee67178SXianjun Jiao cd openwifi 2742ee67178SXianjun Jiao service network-manager stop 2752ee67178SXianjun Jiao ./wgd.sh 27686bab9c1SJiao Xianjun (For fmcomms4, you need an extra command: ./set_ant.sh rx1 tx1) 2772ee67178SXianjun Jiao ifconfig sdr0 up 2782ee67178SXianjun Jiao ifconfig sdr0 192.168.13.1 2792ee67178SXianjun Jiao route add default gw 192.168.10.1 2802ee67178SXianjun Jiao service isc-dhcp-server restart 2812ee67178SXianjun Jiao hostapd hostapd-openwifi.conf 2822ee67178SXianjun Jiao ``` 2832ee67178SXianjun Jiao * On PC: 2842ee67178SXianjun Jiao 2852ee67178SXianjun Jiao ``` 2862ee67178SXianjun Jiao sudo ip route add 192.168.13.0/24 via 192.168.10.122 dev ethX 2872ee67178SXianjun Jiao ``` 288ffe9541bSJiao Xianjun * Now you can connect openwifi hotspot from your phone/laptop and access the internet. 289