#!/bin/sh

: << =cut

=head1 NAME

senderbase - Gives the current SenderBase reputation for a mail host.

SenderBase is a mail server reputation service run by Cisco.  It's
basically a measure of how likely or unlikely they think it is for the
server in question to be sending spam, rated on a scale of -10 (near-100%
chance of spam) to 10 (near-0% chance of spam).  The SenderBase score for
a server is one of several criteria that may be used when doing spam
filtering; consequently, it's useful for the operator of a mail server to
track their current reputation score.

=head1 CONFIGURATION

By default, the script will use the first IP address returned by
C<hostname -I>.  If that's not the right address to use, set the
C<ip_address> environment variable to the appropriate value.  (Note that
if a host has multiple IP addresses, there's no guaranteed ordering for
C<hostname -I>, so you should set the address explicitly in that case.)

 [senderbase]
   env.ip_address 8.8.8.8

=head1 AUTHOR

Phil! Gold <phil_g@pobox.com>

=head1 LICENSE

This plugin is made available under a CC0 waiver:

  https://creativecommons.org/publicdomain/zero/1.0/

=head1 MAGIC MARKERS

 #%# family=auto
 #%# capabilities=autoconf

=cut

if which dig >/dev/null; then
    query_program=dig
    do_query () {
        hostname=$1
        dig +short $hostname TXT | sed 's/"//g' | head -1
    }
elif which host >/dev/null; then
    query_program=host
    do_query () {
        hostname=$1
        host -t TXT $hostname | grep -m 1 'descriptive text' | cut -d\" -f2
    }
else
    query_program=
    do_query () {
        true
    }
fi

real_ip_address="${ip_address:-$(hostname -I | awk '{print $1}')}"
ip_reversed="$(echo $real_ip_address | sed -re 's/^([0-9]+)\.([0-9]+)\.([0-9]+)\.([0-9]+)$/\4.\3.\2.\1/')"
query_host="${ip_reversed}.rf.senderbase.org"

if [ "$1" = "autoconf" ]; then
    if [ -z "$query_program" ]; then
        echo 'no (No "dig" or "host" executable found.)'
    elif [ -z "$(do_query "$query_host")" ]; then
        echo "no (No SenderBase reputation for IP address ${ip_address}.)"
    else
        echo 'yes'
    fi
    exit 0
fi

if [ "$1" = "config" ]; then
    cat <<EOF
graph_category mail
graph_title SenderBase Reputation for $real_ip_address
graph_info Current reputation from senderbase.org.  Ranges from -10 (very poor) through 0 (neutral) to 10 (very good).
graph_args --lower-limit -10 --upper-limit 10
reputation.label Reputation
reputation.warning 0:
reputation.critical -5:
EOF
    exit 0
fi

value="$(do_query "$query_host")"
echo reputation.value "${value:-U}"