# # This file is best read with ``perldoc plugins.pod'' # ### # Conventions: # plugin names: F, F # constants: I # smtp commands, answers: B, B<250 Queued!> # # Notes: # * due to restrictions of some POD parsers, no C<<$object->method()>> # are allowed, use C<$object-Emethod()> # =head1 SMTP hooks This section covers the hooks, which are run in a normal SMTP connection. The order of these hooks is like you will (probably) see them, while a mail is received. Every hook receives a C object of the currently running plugin as the first argument. A C object is the second argument of the current transaction in the most hooks, exceptions are noted in the description of the hook. If you need examples how the hook can be used, see the source of the plugins, which are given as example plugins. B: for some hooks (post-fork, post-connection, disconnect, deny, ok) the return values are ignored. This does B mean you can return anything you want. It just means the return value is discarded and you can not disconnect a client with I. The rule to return I to run the next plugin for this hook (or return I / I to stop processing) still applies. =head2 hook_pre_connection Called by a controlling process (e.g. forkserver or prefork) after accepting the remote server, but before beginning a new instance (or handing the connection to the worker process). Useful for load-management and rereading large config files at some frequency less than once per session. This hook is available in the F, F and F flavours. =cut NOT FOR: apache, -server and inetd/pperl =pod B You should not use this hook to do major work and / or use lookup methods which (I) take some time, like DNS lookups. This will slow down B incoming connections, no other connection will be accepted while this hook is running! Arguments this hook receives are (B: currently no C<%args> for F): my ($self,$transaction,%args) = @_; # %args is: # %args = ( remote_ip => inet_ntoa($iaddr), # remote_port => $port, # local_ip => inet_ntoa($laddr), # local_port => $lport, # max_conn_ip => $MAXCONNIP, # child_addrs => [values %childstatus], # ); B the C<$transaction> is of course C at this time. Allowed return codes are =over 4 =item DENY / DENY_DISCONNECT returns a B<550> to the client and ends the connection =item DENYSOFT / DENYSOFT_DISCONNECT returns a B<451> to the client and ends the connection =back Anything else is ignored. Example plugins are F and F. =head2 hook_connect It is called at the start of a connection before the greeting is sent to the connecting client. Arguments for this hook are my $self = shift; B in fact you get passed two more arguments, which are C at this early stage of the connection, so ignore them. Allowed return codes are =over 4 =item OK Stop processing plugins, give the default response =item DECLINED Process the next plugin =item DONE Stop processing plugins and dont give the default response, i.e. the plugin gave the response =item DENY Return hard failure code and disconnect =item DENYSOFT Return soft failure code and disconnect =back Example plugin for this hook is the F plugin. =head2 hook_helo / hook_ehlo It is called after the client sent B (hook_ehlo) or B (hook_helo) Allowed return codes are =over 4 =item DENY Return a 550 code =item DENYSOFT Return a B<450> code =item DENY_DISCONNECT / DENYSOFT_DISCONNECT as above but with disconnect =item DONE Qpsmtpd wont do anything, the plugin sent the message =item DECLINED Qpsmtpd will send the standard B/B answer, of course only if all plugins hooking I return I. =back Arguments of this hook are my ($self, $transaction, $host) = @_; # $host: the name the client sent in the # (EH|HE)LO line B C<$transaction> is C at this point. =head2 hook_mail_pre After the B line sent by the client is broken into pieces by the C, this hook recieves the results. This hook may be used to pre-accept adresses without the surrounding IE> (by adding them) or addresses like Iuser@example.com.E> or Iuser@example.com E> by removing the trailing I<"."> / C<" ">. Expected return values are I and an address which must be parseable by Cparse()> on success or any other constant to indicate failure. Arguments are my ($self, $transaction, $addr) = @_; =head2 hook_mail Called right after the envelope sender line is parsed (the B command). The plugin gets passed a C object, which means the parsing and verifying the syntax of the address (and just the syntax, no other checks) is already done. Default is to allow the sender address. The remaining arguments are the extensions defined in RFC 1869 (if sent by the client). B According to the SMTP protocol, you can not reject an invalid sender until after the B stage (except for protocol errors, i.e. syntax errors in address). So store it in an C<$transaction-Enote()> and process it later in an rcpt hook. Allowed return codes are =over 4 =item OK sender allowed =item DENY Return a hard failure code =item DENYSOFT Return a soft failure code =item DENY_DISCONNECT / DENYSOFT_DISCONNECT as above but with disconnect =item DECLINED next plugin (if any) =item DONE skip further processing, plugin sent response =back Arguments for this hook are my ($self,$transaction, $sender, %args) = @_; # $sender: an Qpsmtpd::Address object for # sender of the message Example plugins for the C are F and F. =head2 hook_rcpt_pre See C, s/MAIL FROM:/RCPT TO:/. =head2 hook_rcpt This hook is called after the client sent an I command (after parsing the line). The given argument is parsed by C, then this hook is called. Default is to deny the mail with a soft error code. The remaining arguments are the extensions defined in RFC 1869 (if sent by the client). Allowed return codes =over 4 =item OK recipient allowed =item DENY Return a hard failure code, for example for an I message. =item DENYSOFT Return a soft failure code, for example if the connect to a user lookup database failed =item DENY_DISCONNECT / DENYSOFT_DISCONNECT as above but with disconnect =item DONE skip further processing, plugin sent response =back Arguments are my ($self, $transaction, $recipient, %args) = @_; # $rcpt = Qpsmtpd::Address object with # the given recipient address Example plugin is F. =head2 hook_data After the client sent the B command, before any data of the message was sent, this hook is called. B This hook, like B, B, B, B, is an endpoint of a pipelined command group (see RFC 1854) and may be used to detect ``early talkers''. Since svn revision 758 the F plugin may be configured to check at this hook for ``early talkers''. Allowed return codes are =over 4 =item DENY Return a hard failure code =item DENYSOFT Return a soft failure code =item DENY_DISCONNECT / DENYSOFT_DISCONNECT as above but with disconnect =item DONE Plugin took care of receiving data and calling the queue (not recommended) B The only real use for I is implementing other ways of receiving the message, than the default... for example the CHUNKING SMTP extension (RFC 1869, 1830/3030) ... a plugin for this exists at http://svn.perl.org/qpsmtpd/contrib/vetinari/experimental/chunking, but it was never tested ``in the wild''. =back Arguments: my ($self, $transaction) = @_; Example plugin is F. =head2 hook_received_line If you wish to provide your own Received header line, do it here. You can use or discard any of the given arguments (see below). Allowed return codes: =over 4 =item OK, $string use this string for the Received header. =item anything else use the default Received header =back Arguments are my ($self, $transaction, $smtp, $auth, $sslinfo) = @_; # $smtp - the SMTP type used (e.g. "SMTP" or "ESMTP"). # $auth - the Auth header additionals. # $sslinfo - information about SSL for the header. =head2 data_headers_end This hook fires after all header lines of the message data has been received. Defaults to doing nothing, just continue processing. At this step, the sender is not waiting for a reply, but we can try and prevent him from sending the entire message by disconnecting immediately. (Although it is likely the packets are already in flight due to buffering and pipelining). B BE CAREFUL! If you drop the connection legal MTAs will retry again and again, spammers will probably not. This is not RFC compliant and can lead to an unpredictable mess. Use with caution. B This hook does not currently work in async mode. Why this hook may be useful for you, see L, ff. Allowed return codes: =over 4 =item DENY_DISCONNECT Return B<554 Message denied> and disconnect =item DENYSOFT_DISCONNECT Return B<421 Message denied temporarily> and disconnect =item DECLINED Do nothing =back Arguments: my ($self, $transaction) = @_; B check arguments =head2 hook_data_post The C hook is called after the client sent the final C<.\r\n> of a message, before the mail is sent to the queue. Allowed return codes are =over 4 =item DENY Return a hard failure code =item DENYSOFT Return a soft failure code =item DENY_DISCONNECT / DENYSOFT_DISCONNECT as above but with disconnect =item DONE skip further processing (message will not be queued), plugin gave the response. B just returning I from a special queue plugin does (nearly) the same (i.e. dropping the mail to F) and you don't have to send the response on your own. If you want the mail to be queued, you have to queue it manually! =back Arguments: my ($self, $transaction) = @_; Example plugins: F, F =head2 hook_queue_pre This hook is run, just before the mail is queued to the ``backend''. You may modify the in-process transaction object (e.g. adding headers) or add something like a footer to the mail (the latter is not recommended). Allowed return codes are =over 4 =item DONE no queuing is done =item OK / DECLINED queue the mail =back =head2 hook_queue When all C hooks accepted the message, this hook is called. It is used to queue the message to the ``backend''. Allowed return codes: =over 4 =item DONE skip further processing (plugin gave response code) =item OK Return success message, i.e. tell the client the message was queued (this may be used to drop the message silently). =item DENY Return hard failure code =item DENYSOFT Return soft failure code, i.e. if disk full or other temporary queuing problems =back Arguments: my ($self, $transaction) = @_; Example plugins: all F plugins =head2 hook_queue_post This hook is called always after C. If the return code is B I, a message (all remaining return values) with level I is written to the log. Arguments are my $self = shift; B C<$transaction> is not valid at this point, therefore not mentioned. =head2 hook_reset_transaction This hook will be called several times. At the beginning of a transaction (i.e. when the client sends a B command the first time), after queueing the mail and every time a client sends a B command. Arguments are my ($self, $transaction) = @_; B don't rely on C<$transaction> being valid at this point. =head2 hook_quit After the client sent a B command, this hook is called (before the C). Allowed return codes =over 4 =item DONE plugin sent response =item DECLINED next plugin and / or qpsmtpd sends response =back Arguments: the only argument is C<$self> =cut ### XXX: FIXME pass the rest of the line to this hook? =pod Expample plugin is the F plugin. =head2 hook_disconnect This hook will be called from several places: After a plugin returned I, before connection is disconnected or after the client sent the B command, AFTER the quit hook and ONLY if no plugin hooking C returned I. All return values are ignored, arguments are just C<$self> Example plugin is F =head2 hook_post_connection This is the counter part of the C hook, it is called directly before the connection is finished, for example, just before the qpsmtpd-forkserver instance exits or if the client drops the connection without notice (without a B). This hook is not called if the qpsmtpd instance is killed. =cut FIXME: we should run this hook on a ``SIGHUP'' or some other signal? =pod The only argument is C<$self> and all return codes are ignored, it would be too late anyway :-). Example: F =head1 Parsing Hooks Before the line from the client is parsed by Cparse()> with the built in parser, these hooks are called. They can be used to supply a parsing function for the line, which will be used instead of the built in parser. The hook must return two arguments, the first is (currently) ignored, the second argument must be a (CODE) reference to a sub routine. This sub routine receives three arguments: =over 4 =item $self the plugin object =item $cmd the command (i.e. the first word of the line) sent by the client =item $line the line sent by the client without the first word =back Expected return values from this sub are I and a reason which is sent to the client or I and the C<$line> broken into pieces according to the syntax rules for the command. B, the C hook was never implemented,...> =head2 hook_helo_parse / hook_ehlo_parse The provided sub routine must return two or more values. The first is discarded, the second is the hostname (sent by the client as argument to the B / B command). All other values are passed to the helo / ehlo hook. This hook may be used to change the hostname the client sent... not recommended, but if your local policy says only to accept I hosts with FQDNs and you have a legal client which can not be changed to send his FQDN, this is the right place. =head2 hook_mail_parse / hook_rcpt_parse The provided sub routine must return two or more values. The first is either I to indicate that parsing of the line was successfull or anything else to bail out with I<501 Syntax error in command>. In case of failure the second argument is used as the error message for the client. If parsing was successfull, the second argument is the sender's / recipient's address (this may be without the surrounding I> and I>, don't add them here, use the C / C methods for this). All other arguments are sent to the C hook as B / B parameters (see RFC 1869 I for more info). Note that the mail and rcpt hooks expect a list of key/value pairs as the last arguments. =head2 hook_auth_parse B =head1 Special hooks Now some special hooks follow. Some of these hooks are some internal hooks, which may be used to alter the logging or retrieving config values from other sources (other than flat files) like SQL databases. =head2 hook_logging This hook is called when a log message is written, for example in a plugin it fires if someone calls C<$self-Elog($level, $msg);>. Allowed return codes are =over 4 =item DECLINED next logging plugin =item OK (not I, as some might expect!) ok, plugin logged the message =back Arguments are my ($self, $transaction, $trace, $hook, $plugin, @log) = @_; # $trace: level of message, for example # LOGWARN, LOGDEBUG, ... # $hook: the hook in/for which this logging # was called # $plugin: the plugin calling this hook # @log: the log message B C<$transaction> may be C, depending when / where this hook is called. It's probably best not to try acessing it. All F plugins can be used as example plugins. =head2 hook_deny This hook is called after a plugin returned I, I, I or I. All return codes are ignored, arguments are my ($self, $transaction, $prev_plugin, $return, $return_text) = @_; B C<$transaction> may be C, depending when / where this hook is called. It's probably best not to try acessing it. Example plugin for this hook is F. =head2 hook_ok The counter part of C, it is called after a plugin B return I, I, I or I. All return codes are ignored, arguments are my ( $self, $transaction, $prev_plugin, $return, $return_text ) = @_; B C<$transaction> may be C, depending when / where this hook is called. It's probably best not to try acessing it. =head2 hook_config Called when a config file is requested, for example in a plugin it fires if someone calls Cqp-Econfig($cfg_name);>. Allowed return codes are =over 4 =item DECLINED plugin didn't find the requested value =item OK requested values as C<@list>, example: return (OK, @{$config{$value}}) if exists $config{$value}; return (DECLINED); =back Arguments: my ($self,$transaction,$value) = @_; # $value: the requested config item(s) B C<$transaction> may be C, depending when / where this hook is called. It's probably best not to try acessing it. Example plugin is F from the qpsmtpd distribution. =head2 hook_unrecognized_command This is called if the client sent a command unknown to the core of qpsmtpd. This can be used to implement new SMTP commands or just count the number of unknown commands from the client, see below for examples. Allowed return codes: =over 4 =item DENY_DISCONNECT Return B<521> and disconnect the client =item DENY Return B<500> =item DONE Qpsmtpd wont do anything; the plugin responded, this is what you want to return, if you are implementing new commands =item Anything else... Return B<500 Unrecognized command> =back Arguments: my ($self, $transaction, $cmd, @args) = @_; # $cmd = the first "word" of the line # sent by the client # @args = all the other "words" of the # line sent by the client # "word(s)": white space split() line B C<$transaction> may be C, depending when / where this hook is called. It's probably best not to try acessing it. Example plugin is F. =head2 hook_help This hook triggers if a client sends the B command, allowed return codes are: =over 4 =item DONE Plugin gave the answer. =item DENY The client will get a C message, probably not what you want, better use $self->qp->respond(502, "Not implemented."); return DONE; =back Anything else will be send as help answer. Arguments are my ($self, $transaction, @args) = @_; with C<@args> being the arguments from the client's command. =head2 hook_vrfy If the client sents the B command, this hook is called. Default is to return a message telling the user to just try sending the message. Allowed return codes: =over 4 =item OK Recipient Exists =item DENY Return a hard failure code =item DONE Return nothing and move on =item Anything Else... Return a B<252> =back Arguments are: my ($self) = shift; =cut FIXME: this sould be changed in Qpsmtpd::SMTP to pass the rest of the line as arguments to the hook =pod =head2 hook_noop If the client sents the B command, this hook is called. Default is to return C<250 OK>. Allowed return codes are: =over 4 =item DONE Plugin gave the answer =item DENY_DISCONNECT Return error code and disconnect client =item DENY Return error code. =item Anything Else... Give the default answer of B<250 OK>. =back Arguments are my ($self,$transaction,@args) = @_; =head2 hook_post_fork B This hook is only available in qpsmtpd-async. It is called while starting qpsmtpd-async. You can run more than one instance of qpsmtpd-async (one per CPU probably). This hook is called after forking one instance. Arguments: my $self = shift; The return values of this hook are discarded. =head1 Authentication hooks =cut B auth_parse #=head2 auth B #=head2 auth-plain B #=head2 auth-login B #=head2 auth-cram-md5 B =pod See F. =cut # vim: ts=2 sw=2 expandtab