1. 前言
目前wifi调试，最重要的工具有两个：
-
- wpa_supplicant: WiFi Protected Access，网络安全访问
-
- wireless-tools:
wpa_supplicant是一个 独立运行的 守护进程，其核心是一个消息循环，在消息循环中处理WPA状态机、控制命令、驱动事件、配置信息等。
wpa_supplicant 重要包括两个可执行工具：
| 工具 | 说明 | 备注 |
|---|---|---|
| wpa_supplicant | wifi服务器 | 连接wifi，断开wifi，启动热点等 |
| wpa_cli | wifi客户端 | 通过本地socket连接wpa_supplicant，发送命令 |
本博主要讲解wpa_supplicant的用法！
2. wpa_supplicant
2.1 配置文件
指令：cat /etc/wifi/wpa_supplicant.conf
更换wifi可手动修改该配置文件
root@TinaLinux:/usr# cat /etc/wifi/wpa_supplicant.conf
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
update_config=1
ap_scan=1
network={
ssid="ZZ"
key_mgmt=WPA-PSK
psk="officeworking"
priority=2 ##加了优先级，貌似并没有什么卵用
}
network={
ssid="Jimmy"
key_mgmt=WPA-PSK
psk="12345678"
priority=1
}
Notice：详情可参考以下连接
wpa_supplicant.conf配置解析-1
wpa_supplicant.conf配置解析-2
| 选项 | 说明 | 备注 |
|---|---|---|
| ssid | 连接的wifi名称 | |
| key_mgmt | 加密级别 | 无密码为NONE |
| psk | wifi密码 | 无密码则无此项 |
| ctrl_interface | 控制接口 | 外部程序打开该控制接口； 从而管理wpa_supplicant； 默认为 /var/run/wpa_supplicant |
| ctrl_interface_group | 可控制wpa_supplicant的群组ID | 默认为root，ID=0 |
| update_config | 是否允许外部更新/覆盖该配置文件 | 默认是允许的 不允许只需要注释掉（加#） |
| ap_scan | 接入点的扫描和选择 | |
| network | 连接的路由器信息 | 可设置多个，按顺序连接； 第一个连接失败，会尝试第二个 |
2.2 wpa_supplicant 参数信息
| 选项 | 说明 |
|---|---|
| -b | optional bridge interface name |
| -B | run daemon in the background |
| -c | Configuration file |
| -C | ctrl_interface parameter (only used if -c is not) |
| -d | increase debugging verbosity (-dd even more) |
| -D | driver name (can be multiple drivers: nl80211,wext) |
| -e | entropy file |
| -g | global ctrl_interface |
| -G | global ctrl_interface group |
| -h | show this help text |
| -i | interface name |
| -I | additional configuration file |
| -K | include keys (passwords, etc.) in debug output |
| -L | show license (BSD) |
| -N | start describing new interface |
| -o | override driver parameter for new interfaces |
| -O | override ctrl_interface parameter for new interfaces |
| -p | driver parameters |
| -P | PID file |
| -q | decrease debugging verbosity (-qq even less) |
| -t | include timestamp in debug messages |
| -v | show version |
| -W | wait for a control interface monitor before starting |
最常用的指令有如下几个：
- i：指定端口
- c：指定配置文件
- D：指定使用的wifi驱动
如我的系统配置：
eg.
wpa_supplicant -Dnl80211 -iwlan0 -c/etc/wpa_supplicant.conf
驱动解释：
- nl80211 = Linux nl80211/cfg80211
- wext = Linux wireless extensions (generic)
- wired = Wired Ethernet driver
接口解释
| 接口 | IP | 说明 |
|---|---|---|
| Lo | 127.0.0.1 | Local Loopback，虚拟回环接口； 在系统内部接收和发送数据包； 无需驱动程序 |
| br0 | None | 网桥接口 可以将两个接口进行连接 对帧进行转发 |
| eth0 | ABC类网址内网地址 | 以太网接口与网卡对应 每个MAC对应一个以太网接口 其工作完全由网卡相应的驱动程序控制 |
| WLAN0 | 同上 | 无线网卡对应的接口 无线网卡需要对应的驱动程序才能工作 |
Notice
启动wpa_supplicant之前wifi必须先启动，wpa_supplicnat使用在wifi client端口上
wifi启动命令：ifconfig wlan0 up
2.3 wpa_cli 参数信息
shell中键入 wpa_cli后，进入一个交互界面，可输入如下指令进行对应的操作！
Notice：如果不想进入交互界面，可采用 wpa_cli [command]
| 指令 | 缩写 | 说明 |
|---|---|---|
| status | stat | displays the current connection status |
| disconnect | disc | prevents wpa_supplicant from connecting to any access point |
| quit | q | exits wpa_cli |
| terminate | term | kills wpa_supplicant |
| reconfigure | recon | reloads wpa_supplicant with the configuration file supplied (-c parameter) |
| scan | scan | scans for available access points (only scans it, doesn't display anything) |
| scan_result | scan_r | displays the results of the last scan |
| list_networks | list_n | displays a list of configured networks and their status (active or not, enabled or disabled) |
| select_network | select_n | select a network among those defined to initiate a connection (ie select_network 0) |
| enable_network | enable_n | makes a configured network available for selection (ie enable_network 0) |
| disable_network | disable_n | makes a configured network unavailable for selection (ie disable_network 0) |
| remove_network | remove_n | removes a network and its configuration from the list (ie remove_network 0) |
| add_network | add_n | adds a new network to the list. Its id will be created automatically |
| set_network | set_n | shows a very short list of available options to configure a network when supplied with no parameters. |
| get_network | get_n | displays the required parameter for the specified network. See next section for a list of parameters |
| save_config | save_c | saves the configuration |
2.4 手动连接流程
现在演示以下一个完整的联网过程：
0. 前提：启动wpa_supplicant
root@TinaLinux:/# wpa_supplicant -Dnl80211 -iwlan0 -c/etc/wifi/wpa_supplicant.conf -B
Successfully initialized wpa_supplicant
1. 启动wpa_cli
root@TinaLinux:/usr/ty# wpa_cli
wpa_cli v2.6
Copyright (c) 2004-2016, Jouni Malinen and contributors
This software may be distributed under the terms of the BSD license.
See README for more details.
Selected interface 'wlan0'
Interactive mode
2. 扫描附近的网络
> scan
OK
<3>CTRL-EVENT-SCAN-STARTED
<3>CTRL-EVENT-SCAN-RESULTS
<3>WPS-AP-AVAILABLE
<3>CTRL-EVENT-NETWORK-NOT-FOUND
3. 列出扫描到的网络
> scan_result
bssid / frequency / signal level / flags / ssid
30:23:03:d3:3f:bf 2452 -44 [WPA2-PSK-CCMP][WPS][ESS] SJoy Games
64:09:80:7a:49:05 2427 -48 [WPA-PSK-CCMP+TKIP][WPA2-PSK-CCMP+TKIP][WPS][ESS] Xiaomi_4904
30:23:03:d3:46:03 2422 -43 [WPA2-PSK-CCMP][ESS] SJoy Games
4c:ed:fb:82:27:c0 2422 -46 [WPA2-PSK-CCMP][WPS][ESS] AC1900-106
30:23:03:d3:3f:97 2422 -52 [WPA2-PSK-CCMP][WPS][ESS] SJoy Games
b2:52:16:c9:06:d9 2462 -56 [WPA2-PSK-CCMP][WPS][ESS] DIRECT-d9-HP M227f LaserJet
4. 列出当前的配置文件wpa_supplicant.conf中的配置网络
我的配置中没有任何信息
> list_network
network id / ssid / bssid / flags
5. 增加一个network
此处因为没有网络配置，所以从0开始加
> add_network 0
0
> set_network 0 ssid "APP-TEST1" 【设置SSID】
OK
> list_network 【列出当前网络】
network id / ssid / bssid / flags
0 APP-TEST1 any [DISABLED]
> set_network 0 psk "SetPwdYourself" 【设置密码】
OK
> get_network 0 psk
*
6. 使能添加的网络
> enable_network 0
OK
<3>CTRL-EVENT-SCAN-STARTED
<3>CTRL-EVENT-SCAN-RESULTS
<3>WPS-AP-AVAILABLE
> list_network
network id / ssid / bssid / flags
0 APP-TEST1 any [CURRENT]
7. 将刚配置的信息写入到配置文件
> save_config
OK
8. 查看配置文件信息
wpa_supplicant.conf
2.5 自动连接流程
自动连接需要提前配置wpa_supplicant.conf文件，具体配置方式见 2.1节
此处采用shell脚本的形式，避免一条条的手动输入，麻烦！！
#!/bin/sh
# Copyright (C) 2006 OpenWrt.org
#Autor: Jimmy
#Date: 2020-11-06
#Version: v1.0
start_sta() {
echo 0 > /sys/module/bcmdhd/parameters/op_mode
echo /lib/firmware/fw_bcm43438a0.bin > /sys/module/bcmdhd/parameters/firmware_path
ifconfig wlan0 up
if [[ -e "/var/run/wpa_supplicant/wlan0" ]]; then
rm "/var/run/wpa_supplicant/wlan0"
fi
wpa_supplicant -i wlan0 -c /etc/wifi/wpa_supplicant.conf -B
udhcpc -i wlan0 &
}
stop_sta() {
killall wpa_supplicant
killall hostapd
killall udhcpc
killall dnsmasq
ifconfig wlan0 down
}
restart_sta() {
stop_sta
sleep 1s
start_sta
}
start_ap() {
if [[ -z "$1" ]]; then
mac_addr=$(ifconfig wlan0|awk '{print $5}'|cut -c 13-|tr -d ' :\n')
ap_name="SmartLife-$mac_addr"
softap_up $ap_name
else
softap_up $1
fi
}
stop_ap() {
softap_down
}
restart_ap() {
stop_ap
sleep 1s
start_ap $1
}
case $1 in
start_sta)
start_sta
;;
stop_sta)
stop_sta
;;
restart_sta)
restart_sta
;;
start_ap)
start_ap $2
;;
stop_ap)
stop_ap
;;
restart_ap)
restart_ap $2
;;
*)
echo "Input option: $1 was error"
;;
esac
3. udhcpc
DHCP (Dynamic Host Configuration Protocol) ，目的就是方便管理区域网络內的裝置，当一台 PC 连接到区域网络时，可向 DHCP Server 自动获取可用的 IP，并取得 subnet mask，gateway。
既然是网络通信，肯定是要用DHCP的，网络通信方式一般包括如下三种：
-
- 接入已有网络：即作为STA方式，此时DHCP为客户端
-
- 做AP热点：即AP模式，DHCP此时为服务端
-
- 固定IP：DHCP不工作
DHCP的参数如下：
root@TinaLinux:/usr/ty# udhcpc -h
udhcpc: option requires an argument: h
BusyBox v1.24.1 () multi-call binary.
Usage: udhcpc [-fbqRB] [-t N] [-T SEC] [-A SEC/-n]
[-i IFACE] [-s PROG] [-p PIDFILE]
[-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]...
-i,--interface IFACE Interface to use (default eth0)
-s,--script PROG Run PROG at DHCP events (default /usr/share/udhcpc/default.script)
-p,--pidfile FILE Create pidfile
-B,--broadcast Request broadcast replies
-t,--retries N Send up to N discover packets (default 3)
-T,--timeout SEC Pause between packets (default 3)
-A,--tryagain SEC Wait if lease is not obtained (default 20)
-n,--now Exit if lease is not obtained
-q,--quit Exit after obtaining lease
-R,--release Release IP on exit
-f,--foreground Run in foreground
-b,--background Background if lease is not obtained
-S,--syslog Log to syslog too
-r,--request IP Request this IP address
-o,--no-default-options Don't request any options (unless -O is given)
-O,--request-option OPT Request option OPT from server (cumulative)
-x OPT:VAL Include option OPT in sent packets (cumulative)
Examples of string, numeric, and hex byte opts:
-x hostname:bbox - option 12
-x lease:3600 - option 51 (lease time)
-x 0x3d:0100BEEFC0FFEE - option 61 (client id)
-F,--fqdn NAME Ask server to update DNS mapping for NAME
-V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')
-C,--clientid-none Don't send MAC as client identifier
Signals:
USR1 Renew lease
USR2 Release lease