#!/bin/sh

verbose=0
if [[ "$1" = "-v" ]]
then
    verbose=1
    shift
fi

file=""
if [[ "$1" = "-f" ]]
then
    file="$2"
    shift 2
fi

updt=0
if [[ "$1" = "-u" ]]
then
    updt=1
    shift
    ntp_server=$1
else
    ntp_server=$1

    files=$(find /var/log/ntpstats/ntp_pool/$ntp_server -mmin -15 -name "monlist*")
    if [[ "$files" == "" ]]
    then
	updt=1
    else
	use_file=$( ls -tr $files | tail -1 )
    fi
fi

if [[ $# -ne 1 ]]
then
    echo "Usage: `basename $0` IP-address" 1>&2
    exit 1
fi

tmp=`tempfile -m 0600`

ntp_server_slash16=`echo $ntp_server | sed "s/\.[0-9][0-9]*\.[0-9][0-9]*$//"`

if [[ $updt -eq 1 ]]
then
    /usr/local/sbin/xntpdc -q -nc monlist $ntp_server \
	| tail +3 \
	| grep -v -e "^$ntp_server_slash16" \
		  -e "^127\.0\.0\.1" \
		  -e "^10\." \
		  -e "^192\.168\." \
		  >$tmp
else
    cat $use_file >$tmp
fi

[[ -n "$file" ]] && cat <$tmp >$file

cd /var/log/ntpstats/ntp_pool/ || exit 1

if [[ $updt -eq 1 ]]
then
    mkdir -p $ntp_server
    cd $ntp_server || exit 1

    cat <$tmp >monlist_$(date +"%y%m%dT%H%M%S")
fi

files=$(find . -mmin -120 -name "monlist_*")

clients=$( cat $files | sed 's/ .*//' | sort -n | uniq -c | grep -v "^ *1 " )
nclients=$( echo "$clients" | wc -l )

echo "ntp pool clients active on $ntp_server:" $nclients

if [[ $verbose -eq 1 ]]
then
    echo
    echo "Subnets with many clients:"
    echo "$clients" | sed "s/^ *[0-9][0-9]* \([0-9.]*\)\.[0-9][0-9]*$/\1/" \
	| sort | uniq -c | sort -nr | head -5

    echo
    echo "Clients with rapid updates:"
    cat $tmp | while read ip port localip count m ver code avgint lstint
    do 
	if [[ $count -gt 1000  &&  $avgint -lt 64 ]]
	then
	    printf "%-15s %6d %4d\n" $ip $count $avgint
	fi
    done | sort -k 2nr | head -10
fi

rm $tmp