fff-wireguard: Use babel type wired for wireguard babel peers

The babel interface type 'tunnel' has some disadvantageous properties for
our network.

First, babel tries to evaluate the tunnel performance using the rtt. However,
this makes the network quite unstable, as rtt might fluctuate a lot, especially
on less reliable connections (e.g. LTE). Instead of fully falling back to an alternate
route, this rtt evaluation leads to a lot of flapping routes. Additionally, rtt
evaluation changes the metric of routes quite often, which leads to many unnessessary
babel messages in our network.

Also, babeld disables split-horizon processing on 'tunnel' interfaces per default.
However, split-horizon processing can be done in our point-to-point tunnel setup without
any issues and has the advantage of significantly reduced babel messages on a link with
many uplink routes.

Therefore, wireguard babel peers now use the interface type 'wired'.

Signed-off-by: Fabian Bläse <fabian@blaese.de>
Reviewed-by: Johannes Kimmel <fff@bareminimum.eu>
Reviewed-by: Robert Langhammer <rlanghammer@web.de>
[bump PKG_RELEASE, adjust commit title prefix]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

src/packages/fff/fff-wireguard/Makefile

@@ -1,7 +1,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=fff-wireguard
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_BUILD_DIR:=$(BUILD_DIR)/fff-wireguard
 

src/packages/fff/fff-wireguard/files/etc/gateway.d/50-wireguard

@@ -126,7 +126,7 @@ configure() {
 		babel_add_iifrules "$prefixname" || { echo "ERROR: Could not add iif-rules for wgpeer $name"; exit 1; }
 
 		# add babel interface
-		babel_add_interface "$prefixname" "$prefixname" 'tunnel' "$rxcost" || { echo "ERROR: Could not add babeld interface for wgpeer $name"; exit 1; }
+		babel_add_interface "$prefixname" "$prefixname" 'wired' "$rxcost" || { echo "ERROR: Could not add babeld interface for wgpeer $name"; exit 1; }
 	}
 
 	config_load gateway