#!/bin/sh
set -e
sleeptime='10'
tmpfile='/var/tmp/node_exporter/.pfctl_exporter.prom.tmp'
dstfile='/var/tmp/node_exporter/pfctl_exporter.prom'
counters_pat='/var/tmp/node_exporter/.counters.pat'
tracking_pat='/var/tmp/node_exporter/.tracking.pat'

create_patterns() {
    echo x - ${counters_pat}
    sed -E 's/^ *X//' >${counters_pat} << '    COUNTERS'
        X^match .*
        X^bad_offset .*
        X^fragment .*
        X^short .*
        X^normalize .*
        X^memory .*
        X^bad_timestamp .*
        X^congestion .*
        X^ip_option .*
        X^proto_cksum .*
        X^state_mismatch .*
        X^state_insert .*
        X^state_limit .*
        X^src_limit .*
        X^synproxy .*
        X^map_failed .*
        X^max_states_per_rule .*
        X^max_src_states .*
        X^max_src_nodes .*
        X^max_src_conn .*
        X^max_src_conn_rate .*
        X^overload_table_insertion .*
        X^overload_flush_states .*
        X^synfloods_detected .*
    COUNTERS

    echo x - ${tracking_pat}
    sed -E 's/^ *X//' >${tracking_pat} << '    TRACKING'
        X^current_entries .*
        X^searches .*
        X^inserts .*
        X^removals .*
    TRACKING
}

startup() {
    local jail="$1"

    if [ -z "${jail}" ] || ! jpath=$(jls -j "${jail}" path 2>/dev/null) ; then
        echo "Jail not specified or not running" 1>&2
        return 1
    fi

    if ! [ -c "${jpath}/dev/pf" ] ; then
        echo "No /dev/pf in ${jpath}!" 1>&2
        return 1
    fi

    if [ -s "${jpath}/sbin/pfctl" ] &&
       [ -s "{jpath}/libexec/ld-elf.so.1" ] ; then
            J_LD_LIBRARY_PATH='/lib'
            pfctl='/sbin/pfctl'
    elif [ "${jpath%%/root}" = "$jpath" ] &&
         [ -s "${jpath}/root/sbin/pfctl" ] &&
         [ -s "{jpath}/root/libexec/ld-elf.so.1" ]; then
            J_LD_LIBRARY_PATH='/root/lib'
            pfctl='/root/libexec/ld-elf.so.1 /root/sbin/pfctl'
    else
        echo "pfctl binary and/or supporting libraries not found in ${jpath}."
        return 1
    fi
}

jail_collect_stats() {
    local jail="$1"
    LD_LIBRARY_PATH="${J_LD_LIBRARY_PATH}" jexec "${jail}" $pfctl -vvsi 2>/dev/null | \
        tr '-' '_' | \
        /usr/bin/sed -E -e 's/([^ ]) ([^ ])/\1_\2/g' -e 's/^ *//g' | \
        cut -f 1,2 -w | \
        tr '\t' ' '
}

jail_parse_stats() {
    local jail="$1"
    local stats="$2"

    # State tracking table
    IFS="$(printf "\n\r")"
    for l in $(echo "$stats" | grep -f ${tracking_pat} | head -"$(wc -l < ${tracking_pat} | tr -d ' ')") ; do
        unset IFS
        set -- $l
        name=$1 ; value=$2
        echo "jail_pf_states_${name}{name=\"${jail}\"} ${value}"
    done

    # Source tracking table
    IFS="$(printf "\n\r")"
    for l in $(echo "$stats" | grep -f ${tracking_pat} | tail -"$(wc -l < ${tracking_pat} | tr -d ' ')") ; do
        unset IFS
        set -- $l
        name=$1 ; value=$2
        echo "jail_pf_sources_${name}{name=\"${jail}\"} ${value}"
    done

    # Syncookies
    IFS="$(printf "\n\r")"
    tags="name=\"${jail}\""
    for l in $(echo "$stats" | grep -E 'highwater|lowwater|mode|active') ; do
        unset IFS
        set -- $l
        name=$1 ; value=${2%%_%}
        [ "$name" = 'highwater' ] && name='highwater_pct'
        [ "$name" = 'lowwater' ] && name='lowwater_pct'
        tags="${tags},${name}=\"${value}\""
    done
    IFS="$(printf "\n\r")"
    for l in $(echo "$stats" | grep -E 'syncookies|halfopen') ; do
        unset IFS
        set -- $l
        name=${1##syncookies_} ; value=$2
        echo "jail_pf_syncookies_${name}{${tags}} ${value}"
    done

    # Counters
    IFS="$(printf "\n\r")"
    for l in $(echo "$stats" | grep -f ${counters_pat}) ; do
        unset IFS
        set -- $l
        name=$1 ; value=$2
        echo "jail_pf_counters{name=\"${jail}\",counter=\"${name}\"} ${value}"
    done
}

echo "$(date) - Starting up"
create_patterns
if [ ! -s ${tracking_pat} ] || [ ! -s ${counters_pat} ] ; then
    echo "Pattern files not found in $(pwd)"
    exit 1
fi

while sleep "$sleeptime" ; do
    for j in $(jls name) ; do
        echo "Running for ${j}.." 1>&2
        if startup "$j" ; then
            if stats="$(jail_collect_stats "$j")" ; then
                jail_parse_stats "$j" "$stats" >> "$tmpfile"
            else
                echo "$(date) - Failed to collect stats for ${j} - did jail disappear?"
            fi
        else
            echo "Skipping ${j}.." 1>&2
        fi
    done

    if [ "$?" -eq 0 ] ; then
        mv "$tmpfile" "$dstfile"
    else
        rm -f "$dstfile"
    fi
    echo "Sleeping.." 1>&2
done
rm -f ${counters_pat} ${tracking_pat}