fff-babel: Make implementation runtime switchable

Some users might want to prefer one babel implementation over another
for various reasons. Having to compile the firmware from scratch can be
quite tedious in that case.

Instead, make the babel implementation switchable at runtime.

The implementation can be switched manually using the uci option
`babelimpl.impl.impl`, which currently is not upgrade-safe.

Signed-off-by: Fabian Bläse <fabian@blaese.de>
Acked-by: Christian Dresel <freifunk@dresel.systems>

src/packages/fff/fff-babel-bird2/Makefile

@@ -12,7 +12,6 @@ define Package/fff-babel-bird2
 	URL:=https://www.freifunk-franken.de
 	DEPENDS:=+bird2 +bird2c +owipcalc
 	PROVIDES:=fff-babel-implementation
-	CONFLICTS:=fff-babeld
 endef
 
 define Package/fff-babel-bird2/description

src/packages/fff/fff-babel-bird2/files/lib/functions/fff/babeldaemon/bird2

@@ -1,5 +1,9 @@
 # SPDX-License-Identifier: GPL-3.0-only
 
+babel_get_version() {
+	/usr/sbin/bird --version 2>&1 | sed "s/BIRD version /bird-/"
+}
+
 babel_add_interface() {
 	[ "$#" -ne "4" ] && return 1
 
@@ -49,7 +53,7 @@ babel_remove_custom_redistribute_filters() {
 	return 0
 }
 
-babel_apply() {
+babel_apply_implementation() {
 	# error output hidden because apply might be executed without a preceding configure step.
 	if [ -d /tmp/bird/fff ]; then
 		rm -rf /etc/bird/fff
@@ -59,7 +63,7 @@ babel_apply() {
 	return 0
 }
 
-babel_reload() {
+babel_reload_implementation() {
 	/etc/init.d/fff-bird reload
 }
 

src/packages/fff/fff-babel/files/lib/functions/fff/babel

@@ -1,4 +1,8 @@
-. /lib/functions/fff/babeldaemon
+
+implementation=$(uci -q get babelimpl.impl.impl)
+[ -z "$implementation" ] && implementation=babeld
+
+. /lib/functions/fff/babeldaemon/$implementation
 
 babel_add_iifrules() {
 	[ "$#" -ne "1" ] && return 1
@@ -73,3 +77,40 @@ babel_add_peer6addr() {
 
 	return 0
 }
+
+babel_reload() {
+	# switch implementation temporarily
+	case $implementation in
+		bird2)
+			/etc/init.d/babeld stop 2>/dev/null
+			/etc/init.d/fff-bird start
+			;;
+		babeld)
+			/etc/init.d/fff-bird stop 2>/dev/null
+			/etc/init.d/babeld start
+			;;
+	esac
+
+	# call implementation-specific reload commands
+	babel_reload_implementation
+
+	return 0
+}
+
+babel_apply() {
+	# switch implementation persistently
+	case $implementation in
+		bird2)
+			/etc/init.d/babeld disable
+			/etc/init.d/fff-bird enable
+			;;
+		babeld)
+			/etc/init.d/fff-bird disable
+			/etc/init.d/babeld enable
+			;;
+	esac
+
+	babel_apply_implementation
+
+	return 0
+}

src/packages/fff/fff-babeld/files/etc/uci-defaults/30-disable-babeld

@@ -0,0 +1,3 @@
+/etc/init.d/babeld disable
+
+exit 0

src/packages/fff/fff-babeld/files/lib/functions/fff/babeldaemon/babeld

@@ -1,5 +1,9 @@
 # SPDX-License-Identifier: GPL-3.0-only
 
+babel_get_version() {
+	/usr/sbin/babeld -V 2>&1
+}
+
 babel_add_interface() {
 	[ "$#" -ne "4" ] && return 1
 
@@ -86,11 +90,11 @@ babel_remove_custom_redistribute_filters() {
 	return 0
 }
 
-babel_apply() {
+babel_apply_implementation() {
 	uci commit babeld
 }
 
-babel_reload() {
+babel_reload_implementation() {
 	return 0
 }
 

src/packages/fff/fff-layer3/Makefile

@@ -13,6 +13,7 @@ define Package/fff-layer3
 	DEPENDS:=+fff-alfred-monitoring-proxy \
 	         +fff-babel \
 	         +fff-babeld \
+	         +fff-babel-bird2 \
 	         +fff-boardname \
 	         +fff-dhcp \
 	         +fff-layer3-config \

src/packages/fff/fff-nodewatcher/files/usr/lib/nodewatcher.d/10-systemdata.sh

@@ -74,10 +74,12 @@ if [ -x /usr/bin/fastd ]; then
 	SYSTEM_DATA="$SYSTEM_DATA<fastd_version>$(/usr/bin/fastd -v | awk '{ print $2 }')</fastd_version>"
 fi
 
-if [ -x /usr/sbin/babeld ]; then
-	SYSTEM_DATA="$SYSTEM_DATA<babel_version>$(/usr/sbin/babeld -V 2>&1)</babel_version>"
-elif [ -x /usr/sbin/bird ]; then
-	SYSTEM_DATA="$SYSTEM_DATA<babel_version>$(/usr/sbin/bird --version 2>&1 | sed "s/BIRD version /bird-/")</babel_version>"
+if [ -e /lib/functions/fff/babel ]; then
+	. /lib/functions/fff/babel
+	babel_version=$(babel_get_version)
+	if [ $? -eq 0 ]; then
+		SYSTEM_DATA="$SYSTEM_DATA<babel_version>$babel_version</babel_version>"
+	fi
 fi
 
 # example for /etc/openwrt_release: