linux下移植wifi之安装DHCP及其操作（七）

﹏ヽ暗。殇╰゛Y 2022-05-19 00:10 440阅读 0赞

1、 下载、解压  
    输入dh看有哪些应用程序，输入dhclient -v查看一下相关信息，源码获取的网址:https://www.isc.org/software/dhcp/  
    dhcp : 使得WIFI网卡动态获取IP  
    下载地址：  
    tar -xzf dhcp-4.4.1.tar.gz  
    cd dhcp-4.4.1  
      
2、 编译、安装  
    ./configure --host=arm-linux ac\_cv\_file\_\_dev\_random=yes --with-randomdev=no

cd bind  
    修改Makefile:  
    ./configure BUILD\_CC=gcc ac\_cv\_file\_\_dev\_random=yes --host=arm-linux --disable-kqueue

tar xzf bind.tar.gz  
    cd bind-9.8.4-P2  
    修改 lib/export/dns/Makefile.in   
    gen: $\{srcdir\}/gen.c  
            $\{CC\} $\{ALL\_CFLAGS\} $\{LDFLAGS\} -o $@ $\{srcdir\}/gen.c $\{LIBS\}  
    改为  
    gen: $\{srcdir\}/gen.c  
            $\{BUILD\_CC\} $\{ALL\_CFLAGS\} $\{LDFLAGS\} -o $@ $\{srcdir\}/gen.c $\{LIBS\}

cd ../..  
    make DESTDIR=$PWD/tmp install

把文件复制到NFS  
    cd tmp/usr/local  
      
    cp bin/\* /opt/rootfs/bin/  
    cp sbin/\* /opt/rootfs/sbin/  
    cp etc/dhclient.conf.example /opt/rootfs/etc/dhclient.conf  
    cp etc/dhcpd.conf.example /opt/rootfs/etc/dhcpd.conf

cp client/scripts/linux /opt/rootfs/etc/dhclient-script  
    chmod +x /opt/rootfs/etc/dhclient-script  
    并修改   
    \#!/bin/bash  
    改为 /\*linux 下是sh\*/  
    \#!/bin/sh

3、 使用命令：  
    mkdir -p /var/db  
    wpa\_supplicant -B -c/etc/wpa\_wpa2.conf  -iwlan0  
    dhclient wlan0

4、将命令写成脚本去执行  
4.1、 wpa\_action.sh：  
    vim /sbin/wpa\_action.sh   
    \#!/bin/sh  
    IFNAME=$1  
    CMD=$2  
    if \[ "$CMD" = "CONNECTED" \]; then  
       echo connect $IFNAME, dhclient for it > /dev/console  
       dhclient $IFNAME  
    fi  
    if \[ "$CMD" = "DISCONNECTED" \]; then  
       echo disconnect $IFNAME, kill dhclient for it > /dev/console  
       killall dhclient  
    fi  
      
4.2、auto\_wifi.sh   
    vim /sbin/auto\_wifi.sh  
    \#!/bin/sh  
    if \[ $ACTION = "add" \];  
    then                                                
       wpa\_supplicant -B -c/etc/wpa\_wpa2.conf  -iwlan0  
       wpa\_cli -a/sbin/wpa\_action.sh -B  
    else                       
       killall wpa\_supplicant  
       killall wpa\_cli   
       killall dhclient  
    fi

chmod +x /sbin/auto\_wifi.sh   
      
      
4.3、      
    一接入WIFI网卡，就自动执行wpa\_supplicant、wpa\_cli、dhclient。

vim /etc/mdev.conf   
    wlan0 0:0 777 \* /sbin/auto\_wifi.sh

注意点： wlan0没有ip的时候，dhclient wlan0 -d 可以查看调试信息。-d, 调试参数

扩展：  
wpa\_cli command line options

wpa\_cli \[-p<path to ctrl sockets>\] \[-i<ifname>\] \[-hvB\] \[-a<action file>\] \\  
        \[-P<pid file>\] \[-g<global ctrl>\]  \[command..\]  
  -h = help (show this usage text)  
  -v = shown version information  
  -a = run in daemon mode executing the action file based on events from  
       wpa\_supplicant  
  -B = run a daemon in the background  
  default path: /var/run/wpa\_supplicant  
  default interface: first interface found in socket path

Using wpa\_cli to run external program on connect/disconnect  
\-----------------------------------------------------------

wpa\_cli can used to run external programs whenever wpa\_supplicant  
connects or disconnects from a network. This can be used, e.g., to  
update network configuration and/or trigget DHCP client to update IP  
addresses, etc.

One wpa\_cli process in "action" mode needs to be started for each  
interface. For example, the following command starts wpa\_cli for the  
default interface (-i can be used to select the interface in case of  
more than one interface being used at the same time):

wpa\_cli -a/sbin/wpa\_action.sh -B

The action file (-a option, /sbin/wpa\_action.sh in this example) will  
be executed whenever wpa\_supplicant completes authentication (connect  
event) or detects disconnection). The action script will be called  
with two command line arguments: interface name and event (CONNECTED  
or DISCONNECTED). If the action script needs to get more information  
about the current network, it can use 'wpa\_cli status' to query  
wpa\_supplicant for more information.

Following example can be used as a simple template for an action  
script:

\#!/bin/sh

IFNAME=$1  
CMD=$2

if \[ "$CMD" = "CONNECTED" \]; then  
    SSID=\`wpa\_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=\`  
    \# configure network, signal DHCP client, etc.  
fi

if \[ "$CMD" = "DISCONNECTED" \]; then  
    \# remove network configuration, if needed  
    SSID=  
fi