### -*-m4-*-
###
### Transmission to remote hosts for distorted.org.uk Exim configuration.
###
### (c) 2012 Mark Wooding
###

###----- Licensing notice ---------------------------------------------------
###
### This program is free software; you can redistribute it and/or modify
### it under the terms of the GNU General Public License as published by
### the Free Software Foundation; either version 2 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 General Public License for more details.
###
### You should have received a copy of the GNU General Public License
### along with this program; if not, write to the Free Software Foundation,
### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

###--------------------------------------------------------------------------
### Listen for incoming connections.

SECTION(global, daemon)m4_dnl
daemon_smtp_ports = CONF_smtp_port : CONF_submission_port

DIVERT(null)
###--------------------------------------------------------------------------
### Check source addresses for apparently local senders.

SECTION(acl, mail-hooks)m4_dnl
	## Check that a submitted message's sender address is allowable.
	require	 acl = mail_client_addr

SECTION(acl, misc)m4_dnl
mail_client_addr:

	## If this is a message submission then that's handled elsewhere.
	accept	 condition = ${if eq{$acl_c_mode}{submission}}

	## Make sure that the sender matches the client address.  I feel like
	## I want to reject these, but that will break stuff.  For example,
	## if I send mail to an externally hosted address which is really a
	## distribution list containing some local address, then we'll
	## (approximately legitimately) receive mail with an apparently-local
	## sender from a remote host.
	warn	!hosts = ${LOOKUP_DOMAIN($sender_address_domain,
			   {KV(hosts, {$value}{+allnets})},
			   {${if match_domain {$sender_address_domain} \
					      {+public} \
				 {+allnets}{! +allnets}}})}
		  WARNING_HEADER(RCLNTLSNDR,
				 <:Apparently local sender, but received from remote \
				   server.\n\t\
				   sender=$sender_address \
				   host=$sender_host_address:>)

	## OK.
	accept

DIVERT(null)
###--------------------------------------------------------------------------
### Rename locally-meaningful headers in mail from outside.

m4_define(<:DISTORTED_HEADERS:>,
<:X-CONF_header_token-SpamAssassin-Score,
X-CONF_header_token-SpamAssassin-Status:>)

SECTION(acl, data)m4_dnl
	## If this message is coming from outside then rename headers which
	## look like the ones we're likely to add.  This is most relevant for
	## our spam-report headers, because I'm not sure I understand why
	## someone would want to fake an X-Distorted-Warning header.
	warn	!condition = ${if eq{$acl_c_mode}{submission}}
		!hosts = +allnets
		 set acl_m_hdradd = ${if def:acl_m_hdradd{$acl_m_hdradd}}\
			RENAME_HEADERS_ADD(<:DISTORTED_HEADERS:>)
		 set acl_m_hdrrm = ${if def:acl_m_hdrrm{$acl_m_hdrrm:}}\
			RENAME_HEADERS_REMOVE(<:DISTORTED_HEADERS:>)

DIVERT(null)
###--------------------------------------------------------------------------
### The obvious trivial router.

SECTION(routers, remote)m4_dnl
## Send mail on to a host in our own network.  We must apply extra security.
local:
	driver = dnslookup
	domains = ${if bool {${LOOKUP_DOMAIN($domain,
			       {KV(service, {$value}{true})},
			       {false})}} \
		       {}{ ! +public : \
			   CONF_master_domain : \
			   *.CONF_master_domain }}
	self = fail
	transport = smtp_local
	no_more

## Send mail on to unknown hosts.
remote:
	driver = dnslookup
	domains = ${if bool {${LOOKUP_DOMAIN($domain,
			       {KV(service, {$value}{true})},
			       {false})}} \
		       {}{ ! +public }}
	self = fail
	transport = smtp
	no_more

DIVERT(null)
###----- That's all, folks --------------------------------------------------