openwrt 检测网络ping，无法连接国外互联网时重启网络接口

部分公网ip因不知原因无法访问国际互联网，但可以访问国内ip，例如百度可以访问，但亚马逊、必应、微软等国外网站无法访问，需要重新拨号，获取新的ip才有可能访问成功

openwrt 中创建重启脚本 pingtest.sh ，设置到 cron 中定时检测即可

#!/bin/sh

# Script to check connectivity and restart network if condition met
# Ping www.baidu.com 3 times successfully but 8.8.8.8 fails 3 times

# Function to check if ping succeeds (returns 0 if at least one packet received)
ping_check() {
    ping -c 3 -W 1 "$1" >/dev/null 2>&1
    return $?
}

# Check www.baidu.com
if ping_check "www.baidu.com"; then
    # If baidu succeeds, check 8.8.8.8
    if ! ping_check "8.8.8.8"; then
        # Condition met: restart network interface (assuming wan, adjust if needed)
        /etc/init.d/network restart
        logger "Network restarted due to baidu ping success but 8.8.8.8 failure"
    fi
fi