搭建树莓派无线路由器

1. 采购硬件

• 树莓派（去年买的Raspberry Pi 2 Model B 1GB 一直吃灰，不能忍）
• USB无线网卡(购买链接：http://item.jd.com/509932.html)，新版树莓派3自带无线模块，应该无需购买
• 选用设备
  • 网线（方便调试）

2. 装树莓派官方系统，更新，基础配置

• 略（不会配置，找个文档看看）

3. 安装 hostapd + udhcpd

apt-get install -y hostapd udhcpd

• udhcpd 配置

    root@raspberrypi:~# cat /etc/udhcpd.conf
    start 192.168.42.2 # This is the range of IPs that the hostspot will give to client devices.
    end 192.168.42.20
    interface wlan0 # The device uDHCP listens on.
    remaining yes
    #opt dns 8.8.8.8 4.2.2.2 # The DNS servers client devices will use.
    opt dns 223.5.5.5 223.6.6.6 # The DNS servers client devices will use.
    opt subnet 255.255.255.0
    opt router 192.168.42.1 # The Pi's IP address on wlan0 which we will set up shortly.
    opt lease 864000 # 10 day DHCP lease time in seconds

• hostapd 配置

  • 注意driver=rtl871xdrv 不是nl80211，因为奶茶东的usb网卡硬件不一样（rtl8192cu）
  • 替换/usr/sbin/hostapd这个二进制文件（外国友人链接：https://dl.dropboxusercontent.com/u/1663660/hostapd/hostapd）

  因为硬件的适配性问题，默默调试了3-4h，各种搜（树莓派3应该不存在这种问题）

    root@raspberrypi:~# lsusb |grep WLAN
            Bus 001 Device 004: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter
  
    root@raspberrypi:~# lshw -C network
    *-network:0
       description: Wireless interface
       physical id: 1
       bus info: usb@1:1.3
       logical name: wlan0
       serial: e8:4e:06:2a:5e:73
       capabilities: ethernet physical wireless
       configuration: broadcast=yes driver= rtl8192cu ip=192.168.42.1 multicast=yes wireless=IEEE 802.11bg

  hostapd配置

    root@raspberrypi:~# cat /etc/hostapd/hostapd.conf
    interface=wlan0
    driver=rtl871xdrv
    ssid=行者孙
    hw_mode=g
    channel=6
    macaddr_acl=0
    auth_algs=1
    ignore_broadcast_ssid=0
    wpa=2
    wpa_passphrase=haha1234
    wpa_key_mgmt=WPA-PSK
    wpa_pairwise=TKIP
    rsn_pairwise=CCMP

4. 内核 iptable 网络 配置 启动项

• 内核

    root@raspberrypi:~# grep net.ipv4.ip_forward=1 /etc/sysctl.conf
    net.ipv4.ip_forward=1

• iptables

    root@raspberrypi:~# cat /etc/iptables.ipv4.nat
    # Generated by iptables-save v1.4.14 on Sat Apr 30 16:59:41 2016
    *filter
    :INPUT ACCEPT [23:1360]
    :FORWARD ACCEPT [0:0]
    :OUTPUT ACCEPT [21:3136]
    -A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT
    -A FORWARD -i wlan0 -o eth0 -j ACCEPT
    COMMIT
    # Completed on Sat Apr 30 16:59:41 2016
    # Generated by iptables-save v1.4.14 on Sat Apr 30 16:59:41 2016
    *nat
    :PREROUTING ACCEPT [2:156]
    :INPUT ACCEPT [2:156]
    :OUTPUT ACCEPT [1:108]
    :POSTROUTING ACCEPT [0:0]
    -A POSTROUTING -o eth0 -j MASQUERADE
    COMMIT
    # Completed on Sat Apr 30 16:59:41 2016

• 网络配置

    root@raspberrypi:~# cat /etc/network/interfaces
    auto lo
    iface lo inet loopback
    iface eth0 inet dhcp
  
    auto eth0
    allow-hotplug eth0
  
    auto wlan0
    allow-hotplug wlan0
    iface wlan0 inet static
      address 192.168.42.1
      netmask 255.255.255.0
  
    pre-up iptables-restore < /etc/iptables.ipv4.nat

• 启动项

    root@raspberrypi:~# history | grep enable
      103  update-rc.d udhcpd enable
      104  update-rc.d hostapd enable

4. 手机电脑连接测试，效果感人

测试速度很快。主观自我肯定，客观硬件配置的确秒杀绝大部分路由器

ssid：行者孙
password: haha1234

5. 总结

Hi, GNU/linux 陪伴是最长情的告白，等我财务自由了我赚钱给你！

• 消灭没有女朋友的无聊的人山人海的五一假期
• 拥有一个自由控制的linux router
• 自我陶醉
• 物尽所用