Some experimental filters for OpenSMTPD.

README.md

Warning: Filter API is not stable yet.

Filters are not triggered when sending e-mail directly using the sendmail command.

dummy_filter.py

# coding=utf-8
#
# Dummy filter from Gilles Chehade (poolpOrg) written in Python.
#
import filter

def on_connect(id, local, remote, hostname):
    print("on_connect: ", hex(id), local, remote, hostname)
    return filter.accept(id)

def on_helo(id, helo):
    print("on_helo: ", hex(id), helo)
    return filter.accept(id)

def on_mail(id, mail):
    print("on_mail: ", hex(id), mail)
    return filter.accept(id)

def on_rcpt(id, rcpt):
    print("on_rcpt: ", hex(id), rcpt)
    return filter.accept(id)

def on_data(id):
    print("on_data: ", hex(id))
    return filter.accept(id)

def on_dataline(id, line):
    print("on_dataline: ", hex(id), line)
    return filter.writeln(id, line)

def on_eom(id, size):
    print("on_eom: ", hex(id), size)
    return filter.accept(id)

def on_commit(id):
    print("on_commit: ", hex(id))
    return filter.accept(id)

def on_rollback(id):
    print("on_rollback: ", hex(id))
    return filter.accept(id)

def on_disconnect(id):
    print("on_disconnect: ", hex(id))

pushover_filter.pl

#!/usr/bin/perl

# Copyright (c) 2014 Sunil Nimmagadda <[email protected]>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

use 5.20.1;
use warnings;
use experimental 'signatures';

use HTTP::Tiny;

my $hdrs_ref = {};

sub on_data ($id) { $hdrs_ref->{$id} = {}; }

sub on_dataline ($id, $line) {
    smtpd::filter_api_writeln($id, $line);
    my $h = $hdrs_ref->{$id};

    $h->{is_done} = 1 if $line =~ /^$/;    # end of headers
    return if $h->{is_done};

    $h->{From}    = $line if $line =~ /^From:/;
    $h->{To}      = $line if $line =~ /^To:/;
    $h->{Cc}      = $line if $line =~ /^Cc:/;
    $h->{Subject} = $line if $line =~ /^Subject:/;
}

sub on_commit ($id) {
    my $mailaddr = '[email protected]';
    my $h        = $hdrs_ref->{$id};
    my $subject  = $h->{Subject};
    my $from     = $h->{From};

    pushover( $from, $subject ) if grep { /$mailaddr/ } ( $h->{To}, $h->{Cc} );
    delete $hdrs_ref->{$id};
}

sub on_disconnect ($id) { delete $hdrs_ref->{$id}; }

sub on_reset ($id) { delete $hdrs_ref->{$id}; }

sub on_rollback ($id) { delete $hdrs_ref->{$id}; }

sub pushover ($from, $subject) {
    my $token = 'xxxxxx';
    my $user  = 'yyyyyy';
    my $url   = 'https://api.pushover.net/1/messages.json';

    my $pid = fork;
    if ( !defined $pid ) {
        say 'Pushover: fork failed';
        return;
    }
    return if $pid;    # parent exits

    my $res = HTTP::Tiny->new->post_form(
        $url,
        {
            token   => $token,
            user    => $user,
            message => $subject,
            title   => $from
        }
    );

    say "Pushover: ", $res->{status}, " ", $res->{reason};
}

smtpd.conf

filter dummy python "/etc/opensmtpd/dummy_filter.py"

listen on lo filter dummy