Allow a port to be specified in BindToAddress statements.

This can be used to let tinc listen on multiple ports for incoming connections.

doc/tinc.conf.5.in

@@ -129,7 +129,7 @@ If
 is selected, then depending on the operating system both IPv4 and IPv6 or just
 IPv6 listening sockets will be created.
 
-.It Va BindToAddress Li = Ar address Bq experimental
+.It Va BindToAddress Li = Ar address Oo Ar port Oc Bq experimental
 If your computer has more than one IPv4 or IPv6 address,
 .Nm tinc
 will by default listen on all of them for incoming connections.
@@ -137,7 +137,16 @@ Multiple
 .Va BindToAddress
 variables may be specified,
 in which case listening sockets for each specified address are made.
-
+.Pp
+If no
+.Ar port
+is specified, the socket will be bound to the port specified by the
+.Va Port
+option, or to port 655 if neither is given.
+To only bind to a specific port but not to a specific address, use
+.Li *
+for the
+.Ar address .
 .Pp
 This option may not work on all platforms.
 
@@ -452,7 +461,7 @@ Since host configuration files only contain public keys,
 no secrets are revealed by sending out this information.
 .Bl -tag -width indent
 
-.It Va Address Li = Ar address Oo port Oc Bq recommended
+.It Va Address Li = Ar address Oo Ar port Oc Bq recommended
 The IP address or hostname of this tinc daemon on the real network.
 This will only be used when trying to make an outgoing connection to this tinc daemon.
 Optionally, a port can be specified to use for this address.

doc/tinc.texi

@@ -756,12 +756,16 @@ If any is selected, then depending on the operating system
 both IPv4 and IPv6 or just IPv6 listening sockets will be created.
 
 @cindex BindToAddress
-@item BindToAddress = <@var{address}> [experimental]
+@item BindToAddress = <@var{address}> [<@var{port}>] [experimental]
 If your computer has more than one IPv4 or IPv6 address, tinc
 will by default listen on all of them for incoming connections.
 Multiple BindToAddress variables may be specified,
 in which case listening sockets for each specified address are made.
 
+If no @var{port} is specified, the socket will be bound to the port specified by the Port option,
+or to port 655 if neither is given.
+To only bind to a specific port but not to a specific address, use "*" for the @var{address}.
+
 This option may not work on all platforms.
 
 @cindex BindToInterface

src/net_setup.c

@@ -587,12 +587,25 @@ static bool setup_myself(void) {
 		if(cfg)
 			cfg = lookup_config_next(config_tree, cfg);
 
+		char *port = myport;
+
+		if(address) {
+			char *space = strchr(address, ' ');
+			if(space) {
+				*space++ = 0;
+				port = space;
+			}
+
+			if(!strcmp(address, "*"))
+				*address = 0;
+		}
+
 		hint.ai_family = addressfamily;
 		hint.ai_socktype = SOCK_STREAM;
 		hint.ai_protocol = IPPROTO_TCP;
 		hint.ai_flags = AI_PASSIVE;
 
-		err = getaddrinfo(address, myport, &hint, &ai);
+		err = getaddrinfo(address && *address ? address : NULL, port, &hint, &ai);
 		free(address);
 
 		if(err || !ai) {