Some useful dlfunc functions for Exim

ip2country

Get country from reverse dns country tld or from MaxMind GeoIP if not possible (minimizes GeoIP outdated database records). Requires GeoIP C API.

Usage: ${dlfunc{/usr/local/exim/exim-ext.so}{ip2country}{$sender_host_address}}
returns: 2 letter iso code for given ip address or "--" if not found.

get_env

Return given enviroment variable content.

Usage: ${dlfunc{/usr/local/exim/exim-ext.so}{get_env}{PATH}}
returns: enviroment variable content "" if not found.

pipe_message

Runs program injecting current message or file into it's stdin and returning the stdout output.

Usage: ${dlfunc{/usr/local/exim/exim-ext.so}{pipe_message}{app}{file}}
If {file} is ommited, the current message is piped to the application.
returns: application stdout output.

DSpam usage example::

# the trick here is to call dspam in deliver=summary mode, which will
# return only the dspam header, so you only need to add this header
# to the message (no need to reinject it):

  warn    set acl_m13    = ${dlfunc{/usr/local/exim/exim-ext.so}{pipe_message}\
                            {/usr/local/bin/dspam --deliver=summary --client \
                             --mode=teft --user global}}
          set acl_m14    = ${extract {result}{$acl_m13}}
          set acl_m15    = ${extract {signature}{$acl_m13}}

# now you get in acl_m13 the dspam header, the signature in acl_m15
# (if you need it for logging or something else) and the result
# in acl_m14

# you could optionally retrain it if it comes from a very trusted sender:

warn      condition      = [VERY TRUSTED SENDER]
          condition      = ${if match {$acl_m14}{Spam}}
          set acl_m13    = ${dlfunc{/usr/local/exim/exim-ext.so}{pipe_message}\
                           {/usr/local/bin/dspam --user global --client \
                           --class=innocent --source=error \
                           --deliver=summary --signature=$acl_m15}}
          set acl_m14    = Innocent (retrained)
          set acl_m15    =

# deny at SMTP time if it's spam:

deny      condition      = ${if match {$acl_m14}{Spam}}
          message        = Spam not welcome

# and if accepted add the proper header so it could be latter retrained
# if need:

  warn    condition      = ${if def:acl_m14}
          add_header     = $acl_m13

This enables exim to run dspam and add the result header to the message (both at data acl or at transport/router time) without having to run ugly transports which reinject the message again into exim.

surbl

Scans file for url's and test found urls against SURBL and URIBL. Has to be run in mime ACL. Requires libCURL.

Usage: ${dlfunc{/usr/local/exim/exim-ext.so}{surbl}{file}}
returns: surbl result
example::

  warn   set acl_m9     = 0
         decode         = default
          
  warn   condition      = ${if eq{${lc:$mime_content_type}}\
                          {text/plain}}
         set acl_m9     = ${dlfunc{/usr/local/exim/exim-ext.so}\
                          {surbl}{$mime_decoded_filename}}

  warn   condition      = ${if eq{${lc:$mime_content_type}}\
                          {text/html}}
         set acl_m9     = ${dlfunc{/usr/local/exim/exim-ext.so}\
                          {surbl}{$mime_decoded_filename}}

  deny   !condition     = ${if eq {$acl_m9}{0}}
         message        = SPAM not welcome ($acl_m9)
         log_message    = DATA detected SPAM ($acl_m9)

Files

 Name                    Last modified      Size  Description
 Parent Directory                             -   
 Makefile                10-Feb-2007 11:56  779   Makefile
 geoip.c                 10-Feb-2007 11:56  1.0K  Smart ip country detection
 geoip.o                 26-Jul-2006 19:53  9.6K  
 getenv.c                10-Feb-2007 11:56  439   Get enviroment variables
 getenv.o                26-Jul-2006 19:53  5.0K  
 mp-exim.o               26-Jul-2006 19:53  7.3K  
 pipe.c                  10-Feb-2007 11:56  6.0K  Pipe message or file to application and get stdout result
 surbl.c                 10-Feb-2007 11:56  5.6K  Find url's in file and check against SURBL
 surbl.o                 26-Jul-2006 19:53   24K  

By David Saez david (at) ols . es