Add SMTPS/STARTTLS support.mta-smtps-starttls

 - Adds SMTP over SSL/TLS and STARTTLS support to the outgoing
   delivery by spliting the Connection class into three separate
   classes with logic for SMTP, SMTP over SSL/TLS and STARTTLS.
 - The Delivery class loads the added configuratio values and
   selects the appropriate connection based on the configured
   protocol.
 - This requires aiosmtpd at least 1.1a1 for tests to pass,
   as SMTPS support was added there in:
   https://github.com/aio-libs/aiosmtpd/commit/0d33554c4787e575b7dd31b574259c0876dcc9f8

1 files changed, 26 insertions, 5 deletions

diff --git a/src/mailman/mta/base.py b/src/mailman/mta/base.py
index 4cc7742e8..b182da027 100644
--- a/src/mailman/mta/base.py
+++ b/src/mailman/mta/base.py
@@ -22,9 +22,12 @@ import socket
 import logging
 import smtplib
 
+from lazr.config import as_boolean
 from mailman.config import config
+from mailman.interfaces.configuration import InvalidConfigurationError
 from mailman.interfaces.mta import IMailTransportAgentDelivery
-from mailman.mta.connection import Connection
+from mailman.mta.connection import (
+    SMTPConnection, SMTPSConnection, STARTTLSConnection)
 from public import public
 from zope.interface import implementer
 
@@ -39,12 +42,30 @@ class BaseDelivery:
 
     def __init__(self):
         """Create a basic deliverer."""
+        host = config.mta.smtp_host
+        port = int(config.mta.smtp_port)
         username = (config.mta.smtp_user if config.mta.smtp_user else None)
         password = (config.mta.smtp_pass if config.mta.smtp_pass else None)
-        self._connection = Connection(
-            config.mta.smtp_host, int(config.mta.smtp_port),
-            int(config.mta.max_sessions_per_connection),
-            username, password)
+        protocol = config.mta.smtp_protocol
+        verify_cert = as_boolean(config.mta.smtp_verify_cert)
+        verify_hostname = as_boolean(config.mta.smtp_verify_hostname)
+        max_session_count = int(config.mta.max_sessions_per_connection)
+
+        proto = protocol.lower()
+        if proto == 'smtp':
+            self._connection = SMTPConnection(host, port, max_session_count,
+                                              username, password)
+        elif proto == 'smtps':
+            self._connection = SMTPSConnection(host, port, max_session_count,
+                                               verify_cert, verify_hostname,
+                                               username, password)
+        elif proto == 'starttls':
+            self._connection = STARTTLSConnection(host, port,
+                                                  max_session_count,
+                                                  verify_cert, verify_hostname,
+                                                  username, password)
+        else:
+            raise InvalidConfigurationError('mta.smtp_protocol', protocol)
 
     def _deliver_to_recipients(self, mlist, msg, msgdata, recipients):
         """Low-level delivery to a set of recipients.