#!/bin/sh

#
# greylisting for qmail-qfilter
#
# Author: Joerg Backschues
#

# settings
#
# GREYLISTINGDATA    - greylisting data
# GREYLISTINGDELAY   - greylisting delay (in minutes)
# NOGREYLISTING      - disable greylisting
# NOGREYWHITELISTING - disable whitelisting after passing greylisting challenge
#

# disable greylisting, if environment variable NOGREYLISTING is set

EXIST_NOGREYLISTING=${NOGREYLISTING+1}
test -z "$EXIST_NOGREYLISTING" || { echo "qmail-qfilter: greylisting disabled due to NOGREYLISTING from $QMAILUSER@$QMAILHOST to $QMAILRCPTS at $TCPREMOTEIP" | /var/qmail/bin/splogger qmail ; exit 0; }

# settings

GREYLISTINGDB="/var/greylisting/" # path to greylisting db

# standard settings, if environment variables are not set

test -n "$GREYLISTINGDATA" || GREYLISTINGDATA="$TCPREMOTEIP $QMAILUSER@$QMAILHOST $QMAILRCPTS" # greylisting data
test -n "$GREYLISTINGDELAY" || GREYLISTINGDELAY=5                                              # greylisting delay (in minutes)

# disable greylisting for SMTP AUTH users

EXIST_TCPREMOTEINFO=${TCPREMOTEINFO+1}
test -z "$EXIST_TCPREMOTEINFO" || { echo "qmail-qfilter: greylisting disabled due to SMTP AUTH from $QMAILUSER@$QMAILHOST to $QMAILRCPTS at $TCPREMOTEIP" | /var/qmail/bin/splogger qmail ; exit 0; }

# check greylisting db

test -f "$GREYLISTINGDB$GREYLISTINGDATA" || touch "$GREYLISTINGDB$GREYLISTINGDATA"

for i in $(find "$GREYLISTINGDB" -name "$GREYLISTINGDATA" -type f ! -mmin +"$GREYLISTINGDELAY"); do
    echo "qmail-qfilter: greylisting from $QMAILUSER@$QMAILHOST to $QMAILRCPTS at $TCPREMOTEIP" | /var/qmail/bin/splogger qmail;
    echo -n "Zmessage temporary rejected. Please try again later." >&2;
    exit 82; 
done

# pass greylisting challenge

EXIST_NOGREYWHITELISTING=${NOGREYWHITELISTING+1}

if [ -z $EXIST_NOGREYWHITELISTING ] ; then

    # extend greylisting expiration
    
    test -s "$GREYLISTINGDB$GREYLISTINGDATA" || echo -n "1" > "$GREYLISTINGDB$GREYLISTINGDATA"
    touch -t `date -d "\`expr $GREYLISTINGDELAY + 1\` minute ago" +%y%m%d%H%M.%S` "$GREYLISTINGDB$GREYLISTINGDATA"
    echo "qmail-qfilter: greylisting expiration extended from $QMAILUSER@$QMAILHOST to $QMAILRCPTS at $TCPREMOTEIP" | /var/qmail/bin/splogger qmail
    exit 0

else 

    # pass greylisting challenge without greylisting expiration
    
    rm -f "$GREYLISTINGDB$GREYLISTINGDATA"
    echo "qmail-qfilter: pass greylisting challenge without greylisting expiration from $QMAILUSER@$QMAILHOST to $QMAILRCPTS at $TCPREMOTEIP" | /var/qmail/bin/splogger qmail
    exit 0
    
fi