【全志系统 - WIFI - 4】- STA模式

作者: Jimmy_Nie | 来源:发表于2020-12-14 15:43 被阅读0次

1. 前言

目前wifi调试，最重要的工具有两个：

1. wpa_supplicant: WiFi Protected Access，网络安全访问
1. 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 <j@w1.fi> 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：

1. 接入已有网络：即作为STA方式，此时DHCP为客户端
1. 做AP热点：即AP模式，DHCP此时为服务端
1. 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

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