#!/bin/sh
###########################
## Creates greylist entry for Spamcop's top offending /24 (CIDR) IP blocks.
## Usage: greylist-spamcop-offenders [-n] [NUMBER]
##   -n      Show what would be done without modifying the config file.
##           (This lets you paste the results if you don't want automation.)
##   NUMBER  Number of top offending /24 CIDR blocks to list (default=12)
## 
## Edit greylist.conf with an entry like:
##   racl greylist list "spamcop bad 24-blocks" delay 45m autowhite 2d
## 
## Run this from /etc/cron.daily (or root's crontab) for optimal usage.
## Source: http://spamcop.net/w3m?action=map;net=cmaxcnt;mask=65535;sort=spamcnt
## 
## greylist-spamcop-offenders 0.4 (c) 2009 Adam Katz <scriptsATkhopiscom>, AGPL3
###########################
#### This program is free software: you can redistribute it and/or modify
#### it under the terms of the GNU Affero General Public License as
#### published by the Free Software Foundation, either version 3 of the
#### License, or (at your option) any later version.
#### 
#### This program is distributed in the hope that it will be useful,
#### but WITHOUT ANY WARRANTY; without even the implied warranty of
#### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#### GNU Affero General Public License at <http://www.gnu.org/licenses>.
#### 
#### Explicit permission is given to Emmanuel Dreyfus to include this code in
#### the official milter-greylist with the BSD license.
###########################
### Depends on greylist-milter, GNU sed (probably), and POSIX-compliant /bin/sh
### 
### Changelog:
### 0.4, 2009-03-28: up to spec on license
### 0.3, 2008-04-23: restart the milter when done (not needed?)
### 0.2, 2008-04-16: lots of hand-holding options
###########################


prog=`which $0 2>/dev/null||echo $0`
conf=`ls -t /etc/greylist.conf /etc/milter-greylist/greylist.conf /etc/mail/greylist.conf 2>/dev/null |head -n1` # find config file
if ! [ -s "$conf" ]; then
  echo "Can't find/read greylist.conf.  Please install milter-greylist." >&2
  exit 1
fi
tmp=`tempfile 2>/dev/null || mktemp 2>/dev/null || echo /tmp/tmp.gso.$$`
trap "rm -f $tmp" 0 1 2 5 15
spam_ip_blocks='http://spamcop.net/w3m?action=map;net=cmaxcnt;mask=65535;sort=spamcnt;format=text'

unset TEST NUM_TOP_OFFENDERS
while [ -n "$1" ]; do
  if [ "x$1" = "x-n" ] 
    then TEST=true
    elif [ "$1" -ge 1 ] 2>/dev/null # "not a number" errors return false
      then NUM_TOP_OFFENDERS="$1"
    elif echo "x$1" |grep "x--*h" >/dev/null # --help is parsed here
      then sed -e '/^## /!d;s///' -e "s:greylist.conf:$conf:" "$prog"; exit 0
    else echo "${0%%*/}: Skipping unknown argument '$1'" >&2
  fi
  shift
done

start_regex='^list .spamcop bad 24-blocks'
START=`sed -n "/$start_regex/{=;q}" $conf`
[ -n "$START" ] && END=`sed -n "$START,/}/=" $conf |tail -n1` # '}' after $START
TOTAL=`sed -n '$=' $conf`

# If there is no prior entry, we stick it in front of the first list
if [ -z "$END" ] || [ "$END" -ge "$TOTAL" ]; then
  NEW=true

  START=`sed -n "n;/^list /{=;q}" $conf` # skip line 1 (can't subtract 1)

  # Try to back up over comments and blanks
  # before $START; /find non-comments/ {next line; show line num} |get last one
  NON_COMMENT=`sed -n "1,$(($START-1))!d;/^[^#]/{n;=}" $conf |tail -n1`
  [ "$NON_COMMENT" -gt 1 ] 2>/dev/null && START="$NON_COMMENT"

  # We use "lines 0 to (start-1)" + "offenders" + "lines (end+1) to end" ...
  # So if the first list is start=4, we want start=4 and end=3
  # so that we build "lines 0 to 3" + "offenders" + "lines 4 to end"
  END=$(($START-1))
fi

if [ -n "$TEST" ]; then
  echo '"spamcop bad 24-blocks" is currently:'
  if [ "$START" -ge "$END" ] # the hack for no prior entry in the "if" above
    then echo '  (not present in config)'
    else sed -e "$START,$END!d" -e 's/^/  /' $conf
  fi
  echo ''
fi

(
  sed "1,$(($START-1))!d" $conf	# conf before this section
  [ -n "$NEW" ] && echo ''
  echo 'list "spamcop bad 24-blocks" addr { \ # DO NOT EDIT THIS SECTION!'
  unset line i
  for block in `wget -qq -O - "$spam_ip_blocks" 2>/dev/null \
    |sed -e "/\/24\t/!d" -e "s/\t.*//g" -e $((1+${NUM_TOP_OFFENDERS:-12}))q`
  do
    while [ ${#block} -lt 16 ]; do block=" $block"; done # spacing for columns
    line="$line$block "
    i=$((${i:-1}+1)) # increment (to 2 if this is a new row)
    [ $i -gt 4 ] && echo "	$line \\" && unset line i
  done
  [ -n "$i" ] && echo  "	$line \\"
  echo "} # updated by $prog on `date +%Y-%m-%d`"
  [ -n "$NEW" ] && echo ''
  sed "$(($END+1)),\$!d" $conf	# conf after this section
) > $tmp
touch --reference $conf $tmp 2>/dev/null # prep date sync (see touch line below)

if [ -n "$TEST" ]
  then echo '"spamcop bad 24-blocks" would become:'
       sed -e "/$start_regex/,/\}/!d" -e 's/^/  /' $tmp
       echo -n "View proposed configuration file ($tmp) [yN]? "
       read YN
       [ "$YN" = "${YN#[Yy]}" ] || less $tmp
       echo "Discarded changes.  (Run it without '-n' to make it write)."
  elif ! diff -sq $tmp $conf >/dev/null 2>&1; then # only do stuff if new data
    if cp $tmp $conf 2>/dev/null; then # no reminder when the copy fails
         touch --reference $tmp $conf 2>/dev/null # timestamp = manual update
         [ -n "$NEW" ] && echo "Don't forget to activate it!  (See '$0 --help')"
      else echo "${0##*/}: ERROR: Could not write to '$conf'" >&2; exit 1
    fi
    /etc/init.d/milter-greylist reload >/dev/null 2>&1
fi
exit 0