check_reachable

#!/bin/bash

NAGIOS_OK=0
NAGIOS_WARNING=1
NAGIOS_CRITICAL=2
NAGIOS_UNKNOWN=3

PROGNAME="check_reachable"
VERSION="1.0"

print_usage() {
	echo "$PROGNAME $VERSION"
	echo "Usage:"
	echo "$PROGNAME -H TARGET -m HOP -r hop:ROUTE1[,hop2:ROUTE2[,:ROUTE3]]"
	echo " "
	echo "Example:"
	echo "$PROGNAME -H 8.8.8.8 -r 3:192.168.1.254,192.168.2.254"
}

declare -a ROUTE
while getopts dH:l:m:p:r:STw: OPT; do
    case "$OPT" in
        d) DEBUG=1;;
        H) TARGET="$OPTARG";;
        l) LIMIT="$OPTARG";;
        m) MAXTTL="$OPTARG";;
        p) PORT="$OPTARG";;
        r) ROUTE[${#ROUTE[@]}]="$OPTARG";;
        S) SUDO="sudo";;
        T) METHOD="-T";;
        w) WAIT="$OPTARG";;
    esac
done

if [ -z "$TARGET" ]; then
	print_usage
	exit $NAGIOS_UNKNOWN
fi

ERRCODE=$NAGIOS_OK

METHOD=${METHOD:-"-I"}
LIMIT=${LIMIT:-3}

declare -a output
coproc { $SUDO traceroute ${MAXTTL:+'-m'} $MAXTTL ${WAIT:+'-w'} $WAIT $METHOD ${PORT:+'-p'} $PORT $TARGET 2>&1; } &
while read -u ${COPROC[0]} hop line 2>/dev/null; do
    if [[ $hop =~ [[:digit:]][[:digit:]]* ]]; then
        output[$hop]="$hop: $line"
    elif [ $hop = "traceroute" ]; then
        header="$hop $line"
    else
        ERRCODE=$NAGIOS_UNKNOWN
        ERRMSG="$ERRMSG${ERRMSG:+ }$hop $line"
        output[${#output[@]}]="$hop $line"
    fi
    [ -n "$DEBUG" ] && echo "$hop: $line"
    if [ "$line" = "* * *" ]; then
            if [ -z "$unreachable" ]; then
                unreachable=$hop
            elif [ "$hop" -ge "$((unreachable + $LIMIT))" ]; then
                kill -TERM $COPROC_PID
                break
            fi
    else
        unreachable=
    fi
done
wait $COPROC_PID >/dev/null 2>&1
status=$?
[ -n "$DEBUG" ] && echo $status

if [ -n "$unreachable" ]; then
    echo "ERROR $TARGET: unreachable after hop $((unreachable - 1))"
    i=$((unreachable - 3))
    if [ $i -le 0 ]; then
        i=0
    fi
    while [ $i -le $unreachable ]; do
        echo "${output[$i]}"
        i=$((i + 1))
    done   
    exit $NAGIOS_CRITICAL
fi

k=0
while [ $k -lt ${#ROUTE[@]} ]; do
    oIFS="$IFS"
    IFS=",$IFS" 
    set -- ${ROUTE[$k]}
    IFS="$oIFS"

    found=
    declare -a gateways=($@)
    for gw in ${gateways[@]}; do
        case "$gw" in
            *:*)
		h=$(expr $gw : '\([1-9][0-9]*\):.*')
		r=$(expr $gw : '.*:{0,1}\(.*\)')
                ;;
            *)
		r="$gw"
                ;;
        esac
        if [ -n "$h" ]; then
	    case "${output[$h]}" in
		*"$r"*) found=$h;;
		*) ERRCODE=$NAGIOS_WARNING; break;;
	    esac
        else
            i=0
            while [ $i -le ${#output[@]} ]; do
		case "${output[$i]}" in
		    *"$r"*) found=$i; break;;
		esac
                i=$((i + 1))
            done
        fi
    done
    if [ -z "$found" ]; then
	ERRCODE=$NAGIOS_WARNING
	break
    fi
    k=$((k + 1))
done

hop=${#output[@]}
if [ "$ERRCODE" -eq "$NAGIOS_OK" ]; then
    echo "OK ${output[$hop]}"
else
    echo "ERROR $ERRMSG"
fi
exit $ERRCODE