Fix wildcard relay rule

According to Postfix's behavior, we can implement rule priority in this
evaluation order:

1. Recipient rules, by domain or full address
2. Sender rules, by domain or full address
3. Wildcard rule, if none of the above matches

postfix/README.md

@@ -107,5 +107,5 @@ defined with this method:
 
 - `relayrules` Relay host configuration matching a sender or a destination
   pattern. Implementation of sender/recipient based relay rules.
-  Default/fallback "relayhost" (smarthost) is implemented as a wildcard
-  rule.
+  Default/fallback "relayhost" (smarthost) is configured with
+  "default_transport" to support SMTPS too.

postfix/etc/postfix/relaydest.cf

@@ -7,5 +7,5 @@ dbpath = /srv/pcdb.sqlite
 query = SELECT FORMAT('%%s:[%%s]:%%s', transport, host, port) AS route
   FROM relayrules
   WHERE enabled = 1 AND (
-    rule_subject = '%s' AND rule_type IN ('recipient', 'always-bcc', 'wildcard')
+    rule_subject = '%s' AND rule_type IN ('recipient', 'always-bcc')
   )

postfix/usr/local/bin/reload-config

@@ -87,6 +87,11 @@ else
     tmpl_smtp_sender_dependent_authentication='no'
 fi
 tmpl_always_bcc="${POSTFIX_ALWAYS_BCC}"
+tmpl_default_transport=$(pcdbquery "SELECT transport FROM relayrules WHERE rule_type='wildcard' AND rule_subject='*'")
+if [ -z "${tmpl_default_transport}"]; then
+    tmpl_default_transport=smtp
+fi
+tmpl_relayhost=$(pcdbquery "SELECT FORMAT('[%%s]:%%s', host, port) FROM relayrules WHERE rule_type='wildcard' AND rule_subject='*'")
 set +a
 
 envsubst >/etc/postfix/main.cf <"${TEMPLATES_DIR:?}/main.cf"

postfix/usr/local/lib/templates/main.cf

@@ -77,6 +77,8 @@ address_verify_cache_cleanup_interval = 4h
 #
 # Relay authentication rules, SMTP server passwords and TLS policy
 #
+default_transport = ${tmpl_default_transport}
+relayhost = ${tmpl_relayhost}
 smtpd_sender_login_maps = sqlite:${S}meta_directory/senderlogin.cf,
 smtp_sasl_password_maps = sqlite:${S}meta_directory/relaycredentials.cf,
 sender_dependent_relayhost_maps = sqlite:${S}meta_directory/relaysender_nexthop.cf,