wifi的linux应用及配置

linux下应用wifi，AP侧运行程序hostapd，客户端运行wpa_supplicant。官网：http://w1.fi/。

不是所有的无线网卡都支持所有模式，可以查阅Wireless adapters/Chipset table（https://deviwiki.com/wiki/Wireless_adapters/Chipset_table了解芯片是否支持相应模式。

1. wpa_supplicant

wpa_supplicant本是开源项目源码，被谷歌修改后加入Android移动平台，它主要是用来支持WEP，WPA/WPA2和WAPI无线协议和加密认证的，而实际上的工作内容是通过socket（不管是wpa_supplicant与上层还是wpa_supplicant与驱动都采用socket通讯）与驱动交互上报数据给用户，而用户可以通过socket发送命令给wpa_supplicant调动驱动来对WiFi芯片操作。 简单的说，wpa_supplicant就是WiFi驱动和用户的中转站外加对协议和加密认证的支持。

目前可以使用wireless-tools 或wpa_supplicant工具来配置无线网络。请记住重要的一点是，对无线网络的配置是全局性的，而非针对具体的接口。

wpa_supplicant是一个较好的选择，但缺点是它不支持所有的驱动。请浏览wpa_supplicant网站获得它所支持的驱动列表。另外，wpa_supplicant目前只能连接到那些你已经配置好ESSID的无线网络。wireless-tools支持几乎所有的无线网卡和驱动，但它不能连接到那些只支持WPA的AP。

经过编译后的wpa_supplicant源程序可以看到两个主要的可执行工具：wpa_supplicant和wpa_cli。wpa_supplicant是核心程序，它和wpa_cli的关系就是服务和客户端的关系：后台运行wpa_supplicant，使用wpa_cli来搜索、设置、和连接网络。

wpa_supplicant [-BddfhKLqqtuvW] [-P<pid file>] [-g<globalctrl>] \
       [-G<group>] \
       -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>][-p<driver_param>] \
       [-b<br_ifname> [-MN -i<ifname> -c<conf>[-C<ctrl>] [-D<driver>] \
       [-p<driver_param>] [-b<br_ifname>] [-m<P2P Device configfile>] ...

选项

  -b= 可选的桥接接口名称

  -B= 后台运行

  -c= 配置文件路径

  -C= ctrl_interface 参数（仅在-c不使用的时候使用）

  -i= 接口名称

  -d= 增加调试信息详细程度（-dd显示更多）

  -D= 驱动名称

  -f= 将日志输出到默认日志位置（通常为/ tmp）

  -g= 全局ctrl_interface

  -G= 全局 ctrl_interface group

  -K= 包括密钥信息在调试中输出

  -t= 调试信息添加时间戳

  -h= 显示帮助文档

  -L= 显示许可证

  -p= 驱动程序参数

  -P= PID 文件

  -q= 减少调试信息详细程度（-qq更少）

  -u= 驱动 DBus control interface

  -v= 显示版本

  -W= 在启动之前等待control interface monitor

  -M= 开始描述匹配接口

  -N= 开始描述新接口

  -m= P2P Device的配置文件

驱动

 nl80211 = Linux nl80211/cfg80211
 wext = Linux wireless extensions (generic)
 wired = wpa_supplicant wired Ethernet driver
 roboswitch = wpa_supplicant Broadcom switch driver
 bsd= BSD 802.11 support (Atheros, etc.)
 ndis = Windows NDIS driver

wpa_cli

wpa_cli是一个基于文本的前端程序，用于与wpa_supplicant 进行交互。它用于查询当前状态，更改配置，触发事件并请求交互式用户输入。

wpa_cli支持两种模式：交互式和命令行。

wpa_cli命令：

status = 获取当前WPA/EAPOL/EAP 状态

  mib= 获取MIB变量

 help = 显示帮助文档

 interface [ifname] = 连接接口

 level <debug level> = 改变debug等级

license = 显示wpa_cli证书

 logoff = IEEE 802.1X EAPOL state machine logoff

 logon = IEEE 802.1X EAPOL state machine logon

 set= 设置变量

 pmksa = 显示PMKSA缓存

  reassociate= 强制重新连接

 reconfigure =强制wpa_supplicant重新读取配置文件

 preauthenticate <BSSID> = 强制预先认证

 identity <network id> <identity> = 为SSID配置身份

 password <network id> <password> =为SSID配置密码

  pin<network id> <pin> = 为SSID配置引脚

  otp<network id> <password> = 为SSID配置临时密钥

 passphrase <network id> <passphrase> =为SSID配置私钥

 bssid <network id> <BSSID> = 为SSID设置首选BSSID

 list_networks = 列举已经配置的网络

 select_network <network id> = 选择网络（关闭其他）

 enable_network <network id> = 启用网络

 disable_network <network id> = 禁用网络

 add_network = 添加网络

 remove_network <network id> = 删除网络

 set_network <network id> <variable> <value> =设置网络变量

  get_network<network id> <variable> = 获取网络变量

 save_config = 保存当前配置

 disconnect = 断开连接，等待重新连接命令

 scan = 扫描

 scan_results = 扫描结果

 get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = 获取能力

 terminate = 终止wpa_supplicant

 quit = 退出wpa_cli

wpa_cli [-p<path to ctrl sockets>][-i<ifname>] [-hvB] [-a<action file>] \

       [-P<pid file>] [-g<global ctrl>]  [command..]
  -h= 显示使用文档
  -v=显示版本信息
  -a= 以守护进程方式运行
  -B= 后台运行
  默认套接字路径: /var/run/wpa_supplicant
  默认接口:在套接字路径中找到的第一个接口

wpa_passphrase

使用wpa_passphrase快速连接到其SSID已知的网络，wpa_passphrase是一种命令行工具，可生成wpa_supplicant所需的最小配置。

$ wpa_passphrase MYSSID  密码

2. 模式切换

参考明远智睿MY-IMX6-EK200：MYZRIMX6EK200RTL8188EUSWIFIAP

参考正点原子：

#!/bin/sh
#正点原子@ALIENTEK 
#USB WIFI脚本 
#功能:脚本支持station模式、softap模式、bridge模式相互切换（若相互切换不成功，请重启板子）

#使用方法说明
usage_and_exit() {
    echo ""
    echo "*****************************************************************************************"
    echo "*usage: ${0##*/} [-m mode] [-i ssid] [-p psk] [-d device] [-e ethernet] [-h]*"
    echo "*                                                                                       *"
    echo "*station mode eg:${0##*/} -m station -i ssid -p psk -d wlan0                *"
    echo "*                                                                                       *"
    echo "*softap mode eg: ${0##*/} -m softap -d wlan0                                *"
    echo "*                                                                                       *"
    echo "*bridge mode eg:${0##*/} -m bridge -d wlan0 -e eth0                         *"
    echo "*eg: ${0##*/} -m mode mode=[ station | softap | bridge ]                    *" 
    echo "*****************************************************************************************"
    echo ""
    return
}

#使用方法举例：
#source ./alientek_usb_wifi_setup.sh -m bridge -d wlan0 -e eth0
#source ./alientek_usb_wifi_setup.sh -m station -i ALIENTEK -p 15902020353 -d wlan0
#source ./alientek_usb_wifi_setup.sh -m softap -d wlan0


#版本信息
version() {
    echo "version 1.0"
    echo "作者:DZM@ALIENTEK"
}

#获取参数
while [ $# -gt 0 ]; do
  case $1 in
    --help | -h)
      usage_and_exit $0;break;;
    -m) shift; mode=$1; shift; ;;
    -i) shift; ssid=$1; shift; ;;
    -p) shift; psk=$1; shift; ;;
    -d) shift; device=$1; shift; ;;
    -e) shift; ethernet=$1; shift; ;;
    --version) version $0; break;;
    *) usage_and_exit; break; ;;
  esac
done

#判断参数
if [ -n "$mode" ]; then
echo "您的WIFI配置信息是："
echo "mode  : $mode"
fi

if [ -n "$ssid" ]; then
echo "ssid  : $ssid"
echo "psk   : $psk"
fi

if [ -n "$device" ]; then
echo "device: $device"
fi

if [ -n "$ethernet" ]; then
echo "ethernet  : $ethernet"
fi

#kill掉相关进程
processkill()
{
a=$(ps -aux |grep -E "hostapd" | grep -v grep | awk '{print $2}')
if [ -n "$a" ];then
    kill -9 $a
fi

a=$(ps -aux |grep -E "udhcpd" | grep -v grep  | awk '{print $2}')
if [ -n "$a" ];then
    kill -9 $a
fi

a=$(ps -aux |grep -E "wpa_supplicant" | grep -v grep | awk '{print $2}')
if [ -n "$a" ];then
    kill -9 $a
fi

a=$(ps -aux |grep -E "udhcpc" | grep -v grep | awk '{print $2}')
if [ -n "$a" ];then
    kill -9 $a
fi
}

#创建配置wifi的信息
touch /$PWD/wifi.conf
wifi_conf="/$PWD/wifi.conf"

#bridge Mode(桥接模式)
if [ "$mode" == "bridge" ]; then 
    ifconfig $device down
    ifconfig $device up
    ifconfig $ethernet down
    ifconfig $ethernet up 
    sleep 2
    if [ "$WIFI_MODE" == "station" ]; then 
        wpa_supplicant -B -D wext -i $device -c /etc/wpa_supplicant.conf
    fi
    processkill
    sleep 1
    sync
    echo -ne "interface=wlan0\nssid=alientek_bridge\ndriver=rtl871xdrv\nchannel=6\nhw_mode=g\nignore_broadcast_ssid=0\n
auth_algs=1\nwpa=3\nwpa_passphrase=12345678\nwpa_key_mgmt=WPA-PSK\nwpa_pairwise=TKIP\nrsn_pairwise=CCMP\nbridge=br0" > $wifi_conf
    rm -rf /var/lib/misc/*
    touch /var/lib/misc/udhcpd.leases
    udhcpd -fS /etc/udhcpd.conf & 
    ifconfig $device 0.0.0.0
    brctl addbr br0       
    ifconfig $ethernet 0.0.0.0
    brctl addif br0 $ethernet 
    brctl addif br0 $device         
    ifconfig br0 192.168.1.39 netmask 255.255.255.0
    hostapd $wifi_conf -B
    export WIFI_MODE=bridge
fi

#softap Mode（热点模式）
if [ "$mode" == "softap" ]; then
    processkill
    sleep 1
    sync
    echo -ne "interface=wlan0\nssid=alientek_softap\ndriver=rtl871xdrv\nchannel=6\nhw_mode=g\nignore_broadcast_ssid=0\n
auth_algs=1\nwpa=3\nwpa_passphrase=12345678\nwpa_key_mgmt=WPA-PSK\nwpa_pairwise=TKIP\nrsn_pairwise=CCMP" > $wifi_conf
    a=$(ifconfig |grep -E "br0" | grep -v grep | awk '{print $0}')
    if [ -n "$a" ];then
        brctl delif br0 $device
        brctl delif br0 $device
        ifconfig br0 down
    fi     
    rm -rf /var/lib/misc/*
    touch /var/lib/misc/udhcpd.leases
    ifconfig $device up
    sleep 2
    ifconfig $device 192.168.1.38 netmask 255.255.255.0
    udhcpd -fS /etc/udhcpd.conf     &
    hostapd $wifi_conf -B
    export WIFI_MODE=softap
fi

#station Mode（上网模式）
if [ "$mode" == "station" ]; then 
    processkill
    sleep 1
    sync
    a=$(ifconfig |grep -E "br0" | grep -v grep | awk '{print $0}')
    if [ -n "$a" ];then
        brctl delif br0 $device
        brctl delif br0 $device
        ifconfig br0 down
    fi 
    echo -ne "ctrl_interface=/var/run/wpa_supplicant\n
update_config=1\nnetwork={\nssid=\"$ssid\"\npsk=\"$psk\"\n}\n" > $wifi_conf
    rm -rf /var/lib/misc/*
    ifconfig eth0 down
    ifconfig eth1 down
    ifconfig waln0 down
    ifconfig wlan0 up
    sleep 2
    wpa_supplicant -B -D wext -i $device -c $wifi_conf
    udhcpc -R -b -i wlan0
    route add default gw 192.168.1.1
    export WIFI_MODE=station
fi

#删除wifi.conf
rm -rf /$PWD/wifi.conf
case $mode in
    softap|station|bridge)echo "WIFI设置$mode模式完成!"
    ;;

esac

#卸载环境变量
unset device
unset wifi_conf
unset a
unset ethernet
unset mode
unset ssid
unset psk

sync

# Sample udhcpd configuration file (/etc/udhcpd.conf)

# The start and end of the IP lease block

start        192.168.111.20    #default: 192.168.0.20
end        192.168.111.254    #default: 192.168.0.254


# The interface that udhcpd will use

interface    wlp4s0        #default: eth0


# The maximim number of leases (includes addressesd reserved
# by OFFER's, DECLINE's, and ARP conficts

#max_leases    254        #default: 254


# If remaining is true (default), udhcpd will store the time
# remaining for each lease in the udhcpd leases file. This is
# for embedded systems that cannot keep time between reboots.
# If you set remaining to no, the absolute time that the lease
# expires at will be stored in the dhcpd.leases file.

#remaining    yes        #default: yes


# The time period at which udhcpd will write out a dhcpd.leases
# file. If this is 0, udhcpd will never automatically write a
# lease file. (specified in seconds)

#auto_time    7200        #default: 7200 (2 hours)


# The amount of time that an IP will be reserved (leased) for if a
# DHCP decline message is received (seconds).

#decline_time    3600        #default: 3600 (1 hour)


# The amount of time that an IP will be reserved (leased) for if an
# ARP conflct occurs. (seconds

#conflict_time    3600        #default: 3600 (1 hour)


# How long an offered address is reserved (leased) in seconds

#offer_time    60        #default: 60 (1 minute)

# If a lease to be given is below this value, the full lease time is
# instead used (seconds).

#min_lease    60        #defult: 60


# The location of the leases file

#lease_file    /var/lib/misc/udhcpd.leases    #defualt: /var/lib/misc/udhcpd.leases

# The location of the pid file
#pidfile    /var/run/udhcpd.pid    #default: /var/run/udhcpd.pid

# Everytime udhcpd writes a leases file, the below script will be called.
# Useful for writing the lease file to flash every few hours.

#notify_file                #default: (no script)

#notify_file    dumpleases    # <--- useful for debugging

# The following are bootp specific options, setable by udhcpd.

#siaddr        192.168.0.22        #default: 0.0.0.0

#sname        zorak            #default: (none)

#boot_file    /var/nfs_root        #default: (none)

# The remainer of options are DHCP options and can be specifed with the
# keyword 'opt' or 'option'. If an option can take multiple items, such
# as the dns option, they can be listed on the same line, or multiple
# lines. The only option with a default is 'lease'.

#Examles
opt    dns    114.114.114.114 8.8.8.8 
option    subnet    255.255.255.0
opt    router    192.168.111.11
opt    wins    192.168.111.10
option    dns    129.219.13.81    # appened to above DNS servers for a total of 3
option    domain    local
option    lease    864000        # 10 days of seconds


# Currently supported options, for more info, see options.c
#opt subnet
#opt timezone
#opt router
#opt timesrv
#opt namesrv
#opt dns
#opt logsrv
#opt cookiesrv
#opt lprsrv
#opt bootsize
#opt domain
#opt swapsrv
#opt rootpath
#opt ipttl
#opt mtu
#opt broadcast
#opt wins
#opt lease
#opt ntpsrv
#opt tftp
#opt bootfile
#opt wpad

# Static leases map
#static_lease 00:60:08:11:CE:4E 192.168.0.54
#static_lease 00:60:08:11:CE:3E 192.168.0.44

udhcpd.conf