log ipv6 disconnection

watchdog.sh

#!/bin/bash

TEST_URL="http://www.gstatic.com/generate_204"
TRACE_IP="2607:f130:0:ee::1"
STATUS=0

while true; do
    result=$(curl -6 -sS -m 2 "$TEST_URL" 2>&1)
    if [ $? -ne 0 ]; then
        if [ $STATUS -eq 0 ]; then
            STATUS=1
            #echo "$(date -u): $result" >> curl.log
            echo "$(date -u): ipv6 down" >> traceroute.log
            traceroute6 -I -n $TRACE_IP 2>&1 >> traceroute.log
        fi
    else
        if [ $STATUS -eq 1 ]; then
            STATUS=0
            echo "$(date -u): ipv6 restored" >> traceroute.log
            echo '' >> traceroute.log
        fi
    fi
    sleep 20s
done