source: freewrt/package/busybox/files/if-watchdog@ 621d5d2

#! /bin/sh

INTERFACE="$1"
REMOTE_IP="$2"

FAIL_COUNT=0
FAIL_LIMIT=3

while :; do
        LINK_OK=0
        if ip addr show "$INTERFACE" 2>/dev/null | grep -q UP; then
                LINK_OK=1
        fi
        if [ $LINK_OK -eq 0 ]; then
                FAIL_COUNT=$((FAIL_COUNT+1))
        else
                if [ -n "$REMOTE_IP" ]; then
                        if ping -c 1 -q $REMOTE_IP >/dev/null 2>&1; then
                                FAIL_COUNT=0
                        else
                                FAIL_COUNT=$((FAIL_COUNT+1))
                                logger "$0: remote IP not pingable, FAIL_COUNT: $FAIL_COUNT"
                        fi
                else
                        FAIL_COUNT=0
                fi
        fi
        if [ $FAIL_COUNT -ge $FAIL_LIMIT ]; then
                /sbin/reboot -f
        fi
        sleep 60
done