#!/usr/bin/perl

use strict;
use warnings;

our $VERSION = '2.05'; # VERSION
# ABSTRACT: the mtpolicyd executable
# PODNAME: mtpolicyd

use Mail::MtPolicyd;

Mail::MtPolicyd->run();

__END__

=pod

=encoding UTF-8

=head1 NAME

mtpolicyd - the mtpolicyd executable

=head1 VERSION

version 2.05

=head1 DESCRIPTION

mtpolicyd is a policy daemon for postfix access delegation.

It can be configured to accept connections on several ports from a postfix MTA.
For each port a VirtualHost can be configured and for each VirtualHost several
Plugins can be configured.

=head1 NAME

mtpolicyd - a modular policy daemon for postfix

=head1 EXAMPLE

In postfix main.cf:

  smtpd_recipient_restrictions = check_policy_service inet:127.0.0.1:12345

In mtpolicyd.conf:

  # listen on port 12345 (multiple ports can be separated by ',')
  port="127.0.0.1:12345"

  # defined host for this port
  <VirtualHost 12345>
    name=example_vhost
    <Plugin spamhaus_bl>
      module="RBL"
      domain="sbl.spamhaus.org"
      mode=reject
    </Plugin>
  </VirtualHost>

This check will execute a simple RBL lookup against dbl.spamhaus.org.

=head1 COMMANDLINE OPTIONS

  mtpolicyd
    [-h|--help]
    [-c|--config=<file>]
    [-f|--foreground]
    [-l|--loglevel=<level>]
    [-d|--dump_vhosts]

=over

=item -h --help

Show available command line options.

=item -c --config=<file> (default: /etc/mtpolicyd/mtpolicyd.conf)

Specify the path to the configuration file.

=item -f --foreground

Do not fork to background and log to stdout.

=item -l --loglevel=<level>

Overwrite the log level specified in the configuration with the specified level.

=item -d --dump_vhosts

Parse VirtualHosts configuration, print it to stdout and exit.

=back

=head1 CONFIGURATION FILE

The configuration file is implementend with L<Config::General> which allows apache style
configuration files.

mtpolicyd accepts global configuration parameters in the style:

  key=value

Comments begin with '#'.

VirtualHosts must be configured with VirtualHost sections:

  <VirtualHost <portnumber>>
    name=<name of the vhost>
  </VirtualHost>

Each VirtualHost should contain at least on Plugin.

  <VirtualHost <portnumber>>
    name=<name of the vhost>
    <Plugin <name of check> >
      module = "<name of plugin>"
      # plugin options
      key=value
    </Plugin>
  </VirtualHost>

For individual plugin configuration options see the man page of the plugin:

  Mail::MtPolicyd::Plugin::<name of plugin>

=head2 GLOBAL CONFIGURATION OPTIONS

=over

=item user

user id to run as

=item group

group id to run as

=item pid_file

location of the pid file

=item log_level

Verbosity of logging: 0=>'err', 1=>'warning', 2=>'notice', 3=>'info', 4=>'debug'

=item host

ip address to bind to.

=item port

comma separated list of ports to listen on.

=item min_servers (default: 4)

The minimum number of client processes to start.

=item min_spare_servers (default: 4)

The minimum number of client processes that should hanging around idle
and wait for new connections.

If the number of free processes is below this threshold mtpolicyd will start
to create new child processes.

=item max_spare_servers (default: 12)

The maximum number of idle processes.

If the number of idle processes is over this threshold mtpolicyd will start
to shutdown child processes.

=item max_servers (default: 25)

The absolute maximum number of child processes to start.

=item max_requests (default: 1000)

=item max_keepalive (default: 0)

Number of requests after that mtpolicyd closes the connection
or no limit if set to zero.

Should be the same value as smtpd_policy_service_reuse_count_limit (postfix >2.12)
in postfix/smtpd configuration.

=item vhost_by_policy_context (default: 0)

Select VirtualHost by 'policy_context' request field.

The policy_context will be matched against the 'name' field of the VirtualHost.

For example in postfix main.cf use advanced syntax:

  check_policy_service { inet:localhost:12345, policy_context=reputation }
  ...
  check_policy_service { inet:localhost:12345, policy_context=accounting }

In mtpolicyd.conf:

  port="127.0.0.1:12345" # only 1 port
  vhost_by_policy_context=1
  <VirtualHost 12345>
    name=reputation
    ... plugins ...
  </VirtualHost>

  <VirtualHost 12345>
    name=accounting
    ... plugins ...
  </VirtualHost>

The policy_context feature will be available in postfix 3.1 and later.

If you just need small differentiations consider using the L<Mail::MtPolicyd::Plugin::Condition>
plugin to match against plugin_context field.

=item request_timeout

Maximum total time for one request.

=back

=head1 CONFIGURE CONNECTIONS

mtpolicyd has a global per process connection pool.

Connections could be registered within the connection pool using a <Connection>
block within the configuration. You must at least specify the name of the connection
and the module for the connection type.

  <Connection [name of connection]>
    module = "[connection type]"
    # ... addditional parameters
  </Connection>

Connection modules may require additional parameters.

Currently supported connection modules:

=over

=item Sql

Perl DBI based connections for SQL databases.

L<Mail::MtPolicyd::Connection::Sql>

=item Memcached

Connection to a memcached server/cluster.

L<Mail::MtPolicyd::Connection::Memcached>

=item Ldap

Connection to an LDAP directory server.

L<Mail::MtPolicyd::Connection::Ldap>

=back

=head1 SESSION MANAGEMENT

mtpolicyd implements session managemend to cache data across
different checks for requests with the same instance id.

mtpolicy is able to generate a session for each mail passed to it and store it within the
session cache.
The attached session information will be available to all following plugins across
child processes, virtual hosts and ports.

Plugins will use this session information to cache lookup etc. across multiple requests
for the same mail. Postfix will send a query for each recipient and for each configured
check_policy_service call.

To enable the SessionCache specify a <SessionCache> block within your configuration:

  <SessionCache>
    module = "Memcached"
    expire = "300"
    lock_wait=50
    lock_max_retry=50
    lock_timeout=10
  </SessionCache>

The example requires that a connection of type "Memcached" and the name
"memcached" is configured within the connection pool.
For details read L<Mail::MtPolicyd::SessionCache::Memcached>.

As of version 2.00 it is possible to implement different session caches.

Currently there are 2 session cache modules:

=over

=item L<Mail::MtPolicyd::SessionCache::Memcached>

=item L<Mail::MtPolicyd::SessionCache::Redis>

=back

=head1 PROCESSING OF REQUEST

The policy daemon will process all plugins in the order they appear in the configuration file.
It will stop as soon as a plugin returns an action and will return this action to the MTA.

=head1 SCORING

Most plugins can be configured to not return an action if the performed check matched.

For example the RBL module could be set to passive mode and instead a score could be applied
to the request:

  <Plugin spamhaus>
    module = "RBL"
    mode = "passive"
    domain="zen.spamhaus.org"
    score=5
  </Plugin>

Check the documentation of the plugin for certain score/mode parameters.
Plugin may provide more than one mode/score parameters if the do several checks.

Now if you configure more than one RBL check the score will add up.
Later an action can be taken based on the score.
The ScoreAction plugin will return an action based on the score
and the AddScoreHeader plugin will prepend the score as a header to the mail:

  <Plugin ScoreReject>
    module = "ScoreAction"
    threshold = 15
    action = "reject sender ip %IP% is blocked (score=%SCORE%%SCORE_DETAIL%)"
  </Plugin>
  <Plugin ScoreTag>
    module = "AddScoreHeader"
    spam_score=5
  </Plugin>

=head1 UPGRADING

=head2 FROM 1.x to 2.x

With mtpolicyd 2.x configuration of connections and session cache has been changed.

=head3 Database Connections

In mtpolicyd 2.00 the connections defined globaly in the configuration file
have been replaced by a dynamic connection pool.

The global options db_* ldap_* and memcached_* have been removed.

Instead connections are registered within a connection pool.

You can define them using <Connection> blocks:

  <Connection myconn>
    module = "<adapter>"
    # parameter = "value"
    # ...
  </Connection>

In mtpolicyd 1.x:

  db_dsn=DBI:mysql:mtpolicyd
  db_user=mtpolicyd
  db_password=secret

In mtpolicyd 2.x:

  <Connection db>
     dsn = "DBI:mysql:mtpolicyd"
     user = "mtpolicyd"
     password = "secret"
  </Connection>

All SQL modules will by default use the connection registered as "db".

See modules in Mail::MtPolicyd::Connection::* for available connection adapters.

=head3 Session Cache

Starting with mtpolicyd 2.x it is possible to use other session caches then memcached.

The global session_* parameters have been removed.

Instead the session cache is defined by a <SessionCache> block:

  <SessionCache>
    module = "<module>"
    # parameter = "value"
    # ...
  </SessionCache>

A memcached session cache in mtpolicyd v1.x:

  memcached_servers="127.0.0.1:11211"

  session_lock_wait=50
  session_lock_max_retry=50
  session_lock_timeout=10

In mtpolicyd 2.x:

  <Connection memcached>
    servers = "127.0.0.1:11211"
  </Connection>

  <SessionCache>
    module = "Memcached"
    # defaults to connection "memcached"
    # memcached = "memcached"
    lock_wait = "50"
    lock_max_retry = "50"
    lock_timeout = "10"
  </SessionCache>

If no <SessionCache> is defined it will default to the
dummy session cache module "None".

See modules in Mail::MtPolicyd::SessionCache::* for available session
cache modules.

=head1 AUTHOR

Markus Benning <ich@markusbenning.de>

=head1 COPYRIGHT AND LICENSE

This software is Copyright (c) 2014 by Markus Benning <ich@markusbenning.de>.

This is free software, licensed under:

  The GNU General Public License, Version 2, June 1991

=cut