Automatically restart the device when the network is unavailabled

network-check.sh

#!/bin/bash

. /etc/profile > /dev/null 2>&1

# PUB_DNS='1.1.1.1'
# CHINA ONLY
PUB_DNS='223.5.5.5'

# percentage
REBOOT_THRESHOLD=80

MAXIMUM_TEST_COUNT=10
# second
TEST_INTERVAL=10

PING_COUNT=5

function show_info(){
    echo "TEST DNS: ${PUB_DNS}"
    echo "TEST INTERVAL: ${TEST_INTERVAL}"
    echo "TEST COUNT: ${MAXIMUM_TEST_COUNT}"
    echo "Ping Count: ${PING_COUNT}"
}

function main(){
    show_info

    unavailable_count=0
    for x in $(seq 1 ${MAXIMUM_TEST_COUNT})
    do
        ping -c ${PING_COUNT} ${PUB_DNS} &> /dev/null
        if [[ $? -ne 0 ]]
        then
            echo "The network may be unavailable. Test: ${x}"
            ((unavailable_count++))
        else
            echo "The network is available. Test: ${x}"
        fi
        sleep ${TEST_INTERVAL}s
    done
    unavailable_threshold=$(awk 'BEGIN{printf "%d\n",('${unavailable_count}'/'${MAXIMUM_TEST_COUNT}')*100}')
    if [[ ${unavailable_threshold} -ge ${REBOOT_THRESHOLD} ]]
    then
        echo "The network is unavailable and the device will be reboot."
        reboot
    fi
}

main