一、目的

        4G模组拨号成功后，发现还是不能正常连接外网。

        这时还需要通过dhcp来获取ip，同时需要修改/etc/resolv.conf配置域名后才能正常上网；另外我们还担心网络是否会出现异常，此时需要守护网络的健康，让网络实时在线。

        这里记录调试过程，并提供编写的可用脚本和配置文件。

        主要包含：

1. 4G模组自动拨号上网脚本，自动设置DNS等网络操作
2. 网络守护脚本
3. 系统工具配置
4. 计划任务设置
5. 开机脚本自动运行配置

二、准备

1.移植L610到openwrt下，通过4G CAT1实现ECM拨号上网

        这步骤这里不重复介绍

2.openwrt开发板 MT7628D

        Barrier Breaker 版本号是14.07，linux内核版本3.10.14

3.编译host主机：ubuntu 14.04.5 LTS

4.L610和 MT726D通过USB连接

三、步骤

3.1 编译openwrt系统

进入主目录

# make menuconfig# make V=99

编译后的输出目录在builddir目录下

其中固件在bin/ramips/

3.2 修改openwrt配置

因为配置需要用到几个工具，需要配置起来，可以参考如下来设置

3.2.1 编译microcom工具

# make menuconfig

后找到microcom勾选，microcom是一个串口工具，是用于和4G模组的AT命令测试的。非必选，调试用。

3.2.2 编译comgt工具

同样方法找打comgt工具编译，comgt工具可以用来配置拨号脚本

配置好后，保存

# make V=99

系统中要配置到这里完成，重新烧录系统即可。

3.3 编写4G模组自动拨号上网脚本

整体流程如下：

• 按照模组手册提供的交互流程，配置好GCom脚本，实现自动拨号命令
• 拨号完成后用dhcp协议获取IP
• 配置udchpc命令对应DNS脚本
• 编辑网络监控守护脚本
• 开机自动拨号

3.3.1 配置comgt的gcom脚本

配置模组模式为ECM，详见dialog-ecm.gcom文件

opengt set com 115200n81 set comecho off set senddelay 0.02 waitquiet 0.2 0.2 flash 0.1:start send "AT+GTUSBMODE=74^m" waitfor 30 "OK","ERROR" if % = -1 Goto error if % = 0 goto ready if % = 1 goto error:error print $s," ***setusbmode ERROR***" exit 1:ready print "setusbmode OK\n" exit 0

配置模组自动拨号，详见dialog.gcom文件

opengt set com 115200n81 set comecho off set senddelay 0.02 waitquiet 0.2 0.2 flash 0.1:start send "AT+CPIN?^m" waitfor 30 "SIM PUK","SIM PIN","READY","ERROR","ERR" if % = -1 goto error if % = 0 goto ready if % = 1 goto error if % = 2 goto ready if % = 3 goto error if % = 4 goto error:error print $s," ***SIM ERROR***" print "Check device port configuration.\nCheck SIM is inserted\nTest SIM in a mobile phone?\n" exit 1:ready print "SIM ready\n":waitreg send "AT+CGREG?^m" waitfor 2 print $s:signal send "AT+CSQ?^m" get 2 "^m" $s get 2 "^m" $s let a=len($s) let a=a-6 let $s=$right($s,a) if $s <> "0,0" goto sigcont if c > 3 goto sigexit let c=c+1 pause 1 goto signal:sigexit print "Signal strength measure 0,0 too low!" exit 1:sigcont print "Signal Quality:",$s,"\n":SetGTRNDIS send "AT+GTRNDIS=1,1^m" waitfor 3 "OK","ERROR" print $s:GetGTRNDIS send "AT+GTRNDIS?^m" get 2 "^m" $s print $s get 2 "^m" $s print $s:OK print "Set LTE module OK\n"  exit 0  

3.3.2 编辑网络监控守护脚本

这里把拨号获取dhcp以及配置dns写到一个脚本中

详见watch_network.sh文件

#!/bin/sh#sleep 100DATE=`date +%Y-%m-%d-%H:%M:%S`tries=0HOST_URL="aliyuncs.com"USB_MODE_CMD="comgt -d /dev/ttyUSB0 -s /root/arm-target/dialog-ecm.gcom"DIALOG_CMD="comgt -d /dev/ttyUSB0 -s /root/arm-target/dialog.gcom"KILL_UDHCPC_CMD="ps | grep udhcpc | grep -v grep |  awk '{print $1}'|xargs kill -9"LOG_FILE="/tmp/watch_network.log"echo $DATE --- watch network start --- >> $LOG_FILEwhile [[ $tries -lt 3 ]]do        if /bin/ping -c 1 $HOST_URL >/dev/null        then                echo $DATE --- exit --- >> $LOG_FILE                echo $DATE OK >> $LOG_FILE                exit 0        fi        tries=$((tries+1))        sleep 5#       echo $DATE tries: $tries >>watch_network.logdone echo $DATE network restart >> $LOG_FILE# rerst LTEgpio setdir 37 1gpio write 37 1sleep 1gpio write 37 0sleep 5# set ecmmode$USB_MODE_CMD# rerst LTE againgpio setdir 37 1gpio write 37 1sleep 1gpio write 37 0sleep 5# call comgt dialog$DIALOG_CMDsleep 3# udhcpc# kill udhcpc tiwce$KILL_UDHCPC_CMD$KILL_UDHCPC_CMDecho $DATE start dhcpc >> $LOG_FILEudhcpc -i eth1 -s /usr/share/udhcpc/default-dns.script#/etc/init.d/network restart#echo $DATE reboot >>watch_network.log#reboot1

3.3.3 配置udchpc命令对应DNS脚本

上传default-dns.script文件到板子的目录：/usr/share/udhcpc/default-dns.script，并给权限

# chmod 775 /usr/share/udhcpc/default-dns.script

#!/bin/sh# udhcpc script edited by Tim Riker  RESOLV_CONF="/etc/resolv.conf" [ -n "$1" ] || { echo "Error: should be called from udhcpc"; exit 1; } NETMASK=""[ -n "$subnet" ] && NETMASK="netmask $subnet"BROADCAST="broadcast +"[ -n "$broadcast" ] && BROADCAST="broadcast $broadcast" case "$1" in        deconfig)                echo "Setting IP address 0.0.0.0 on $interface"                busybox ifconfig $interface 0.0.0.0                ;;         renew|bound)                echo "Setting IP address $ip on $interface"                busybox ifconfig $interface $ip $NETMASK $BROADCAST                 if [ -n "$router" ] ; then                        echo "Deleting routers"                        while busybox route del default gw 0.0.0.0 dev $interface ; do    :                        done                         metric=0                        for i in $router ; do    echo "Adding router $i"    busybox route add default gw $i dev $interface metric $metric    : $(( metric += 1 ))                        done                fi                 echo "Recreating $RESOLV_CONF"                # If the file is a symlink somewhere (like /etc/resolv.conf                # pointing to /run/resolv.conf), make sure things work.                realconf=$(readlink -f "$RESOLV_CONF" 2>/dev/null || echo "$RESOLV_CONF")                tmpfile="$realconf-$$"                > "$tmpfile"                [ -n "$domain" ] && echo "search $domain" >> "$tmpfile"                for i in $dns ; do                        echo " Adding DNS server $i"                        echo "nameserver $i" >> "$tmpfile"                done                busybox mv "$tmpfile" "$realconf"                ;;esac exit 0

3.3.4 计划任务

在cron中增加网络监控守护脚本，每5分钟执行一次：

# crontab -e

输入内容：

*/5 * * * * /root/arm-target/watch_network.sh

按ESC后，按： 输入qw

查看任务

# crontab -l

3.3.5 开机自动拨号

开机自动拨号可以在上电初次的时候，增加拨号速度，而不用每次等待网络监控守护脚本的执行周期

上传文件到板子：/etc/init.d/startAutoDialog

给权限

# chmod 775 /etc/init.d/startAutoDialog

#!/bin/sh # /etc/init.d/startAutoDialogSTART=95start(){/root/run_dialog.sh &}stop(){}

创建链接

# ln -s /etc/init.d/startAutoDialog /etc/rc.d/S95startAutoDialog

#!/bin/sh # /root/run_dialog.shPROJECT_DIR="/root/"DATE=`date +%Y-%m-%d-%H:%M:%S`echo $DATE run dialog > $PROJECT_DIR/auto_dialog.log# start LTEcd $PROJECT_DIR/./watch_network.sh &

四、验证

以上配置完成后，检查sim卡，天线硬件连接OK后，重启板子。

ping 测试网络

# ping www.baidu.com

来源地址：https://blog.csdn.net/fzhenyu/article/details/126408605