Rewrite bind_interface docs, update changelog.

ChangeLog.txt

@@ -7,16 +7,22 @@ Broker features:
 - auto_id_prefix now defaults to 'auto-'.
 - Add max_keepalive option, to allow a maximum keepalive value to be set for
   MQTT v5 clients only.
+- Add TLS Engine support.
+- Add `bind_interface` option which allows a listener to be bound to a
+  specific network interface, in a similar fashion to the `bind_address` option.
+  Linux only.
 
 Client library features:
 - Add mosquitto_subscribe_multiple() for sending subscriptions to multiple
   topics in one command.
+- Add TLS Engine support.
 
 Client features:
 - Add -E to mosquitto_sub, which causes it to exit immediately after having
   its subscriptions acknowledged. Use with -c to create a durable client
   session without requiring a message to be received.
 - -V now accepts `5, `311`, `31`, as well as `mqttv5` etc.
+- Add TLS Engine support.
 
 Client fixes:
 - mosquitto_pub wouldn't always publish all messages when using `-l` and

man/mosquitto.conf.5.xml

@@ -808,8 +808,24 @@
 					<listitem>
 						<para>Listen for incoming network connections only on
 							the specified interface. This is similar to the
-							preceding option but useful when an interface has
-							multiple addresses or the address may change.</para>
+							<option>bind_address</option> option but is useful
+							when an interface has multiple addresses or the
+							address may change.</para>
+						<para>It is valid to use this option together with
+							<option>bind_address</option> for the default
+							listener, or the <replaceable>bind
+								address/host</replaceable> part of the
+							<option>listener</option> definition.  Care should
+							be taken to ensure that the address being bound to
+							is on the interface being bound to.  If you set the
+							<option>bind_interface</option> to be
+							<replaceable>eth0</replaceable>, and
+							<option>bind_address</option> to
+							<replaceable>127.0.0.1</replaceable>, then the
+							broker will start correctly but you will be unable
+							to connect.</para>
+						<para>This option is currently only available on
+							Linux, and requires elevated privileges.</para>
 						<para>Not reloaded on reload signal.</para>
 					</listitem>
 				</varlistentry>

mosquitto.conf

@@ -208,9 +208,12 @@
 #port 1883
 
 # Bind the listener to a specific interface. This is similar to
-# bind_address above but useful when an interface has multiple
-# addresses or the address may change. Only available on Linux.
-#bind_interface eth0
+# bind_address above but is useful when an interface has multiple addresses or
+# the address may change. It is valid to use this with the bind_address option,
+# but take care that the interface you are binding to contains the address you
+# are binding to, otherwise you will not be able to connect.
+# Example: bind_interface eth0
+#bind_interface
 
 # The maximum number of client connections to allow. This is 
 # a per listener setting.
@@ -359,6 +362,17 @@
 # listener port-number [ip address/host name]
 #listener
 
+# Bind the listener to a specific interface. This is similar to
+# the [ip address/host name] part of the listener definition, but is useful
+# when an interface has multiple addresses or the address may change. It is
+# valid to use this with the [ip address/host name] part of the listener
+# definition, but take care that the interface you are binding to contains the
+# address you are binding to, otherwise you will not be able to connect.
+# Only available on Linux and requires elevated privileges.
+#
+# Example: bind_interface eth0
+#bind_interface
+
 # The maximum number of client connections to allow. This is 
 # a per listener setting.
 # Default is -1, which means unlimited connections.