mldpoker: initial package

A small utility that pokes sleepy devices for MLD Reports.

A workaround for:

* Roaming issues with Linux <= 4.9:
  -> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a088d1d73a4bcfd7bc482f8d08375b9b665dc3e5

* Android devices being unresponsive to MLD Queries in sleep mode:
  -> freifunk-gluon/gluon#1832
  -> https://issuetracker.google.com/issues/149630944

net/mldpoker/Makefile

@@ -0,0 +1,51 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=mldpoker
+PKG_VERSION:=1
+PKG_RELEASE:=1
+
+PKG_LICENSE:=GPLv2
+PKG_LICENSE_FILES:=
+
+PKG_SOURCE_URL:=https://github.com/T-X/mldpoker.git
+PKG_SOURCE_PROTO:=git
+PKG_SOURCE_DATE:=2019-03-08
+PKG_SOURCE_VERSION:=1b14b2da34239b7954767e7a9c6c759bab3d72de
+PKG_MIRROR_HASH:=skip
+
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/mldpoker
+  TITLE:=A small utility that pokes sleepy devices for MLD Reports
+  SECTION:=net
+  CATEGORY:=Network
+endef
+
+define Package/mldpoker/description
+	A small utility that pokes sleepy devices for MLD Reports
+
+	If a host behind IFNAME newly appeared or was unresponsive for
+	at least 15 seconds and now reappeared then MLD Poker sends a
+	general MLDv1 Query with an MLD Maximum Query Response Delay of
+	0 to it (request for an immediate, undelayed MLD Report). The
+	MLD Query is sent to the target host directly via its unicast MAC
+	address.
+
+	This tool was written to work around the following two issues:
+
+	Roaming issues with Linux <= 4.9:
+	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a088d1d73a4bcfd7bc482f8d08375b9b665dc3e5
+
+	Android devices being unresponsive to MLD Queries in sleep mode:
+	https://github.com/freifunk-gluon/gluon/issues/1832
+	https://issuetracker.google.com/issues/149630944
+endef
+
+define Package/mldpoker/install
+	$(CP) ./files/* $(1)/
+	$(INSTALL_DIR) $(1)/usr/sbin/
+	$(CP) $(PKG_BUILD_DIR)/mldpoker $(1)/usr/sbin/mldpoker
+endef
+
+$(eval $(call BuildPackage,mldpoker))

net/mldpoker/files/etc/hotplug.d/iface/60-mldpoker

@@ -0,0 +1,41 @@
+mldpoker_start_check() {
+	local brtype="`uci get network.$INTERFACE.type`"
+
+	if [ ! "$brtype" = "bridge" ] ||
+	   [ ! "`cat /sys/class/net/$DEVICE/bridge/multicast_snooping`" = "1" ] ||
+	   [ ! "`cat /sys/class/net/$DEVICE/bridge/multicast_querier`" = "1" ]; then
+		return 1
+	fi
+
+	return 0
+}
+
+mldpoker_start() {
+	local iface
+
+	mldpoker_start_check || exit 0
+
+	for iface in /sys/class/net/$DEVICE/brif/*; do
+		/etc/init.d/mldpoker start "${iface##*/}"
+	done
+}
+
+mldpoker_stop() {
+	for iface in /sys/class/net/$DEVICE/brif/*; do
+		/etc/init.d/mldpoker stop "${iface##*/}"
+	done
+}
+
+
+[ "`uci get mldpoker.@general[0].disabled`" = "1" ] && exit 0
+
+
+if [ "$ACTION" = "ifup" ]; then
+	logger -t mldpoker "Hotplug: Starting mldpokers for bridge $DEVICE"
+	mldpoker_start
+elif ["$ACTION" = "ifdown" ]; then
+	logger -t mldpoker "Hotplug: Stopping mldpokers for bridge $DEVICE"
+	mldpoker_stop
+else
+	logger -t mldpoker "Hotplug: Unknown ACTION: $ACTION for $DEVICE"
+fi

net/mldpoker/files/etc/init.d/mldpoker

@@ -0,0 +1,105 @@
+#!/bin/sh /etc/rc.common
+
+USE_PROCD=1
+
+br_is_querier() {
+	local brport="$1"
+	local has_snooping="`cat /sys/class/net/$brport/brport/bridge/bridge/multicast_snooping 2>/dev/null`"
+	local has_querier="`cat /sys/class/net/$brport/brport/bridge/bridge/multicast_querier 2>/dev/null`"
+
+	[ "$has_snooping" = "1" ] && [ "$has_querier" = "1" ] && \
+		return 0
+
+	return 1
+}
+
+check_blacklisted() {
+	local iface="$1"
+	local ret=0
+
+	for blk in `uci get mldpoker.@blacklist[0].ifname`; do
+		echo "$blk" | grep -q "^$iface\$" && {
+			ret=1
+			break
+		}
+	done
+
+	return $ret
+}
+
+start_instance() {
+	local iface="$1"
+	local briface
+
+	briface="`grep "INTERFACE" /sys/class/net/bat0/brport/bridge/uevent 2>/dev/null`"
+	briface="${briface#*=}"
+
+	check_blacklisted "$iface" || return
+
+        procd_open_instance "mldpoker-$iface"
+        procd_set_param command /usr/sbin/mldpoker $iface
+
+        # respawn automatically if something died, be careful if you have an alternative process supervisor
+        # if process dies sooner than respawn_threshold, it is considered crashed and after 5 retries the service is stopped
+        procd_set_param respawn ${respawn_threshold:-3600} ${respawn_timeout:-5} ${respawn_retry:-5}
+
+        procd_set_param netdev $iface # likewise, except if dev's ifindex changes.
+        procd_set_param stdout 0 # forward stdout of the command to logd
+        procd_set_param stderr 1 # same for stderr
+        procd_set_param pidfile /var/run/mldpoker-$iface.pid # write a pid file on instance start and remove it on stop
+        procd_close_instance
+
+	logger -t mldpoker "Starting mldpoker instance for $iface on $briface"
+}
+
+start_all_instances() {
+	for brport in /sys/class/net/*/brport/; do
+		brport=${brport%/*/}
+		brport=${brport##*/}
+
+		br_is_querier "$brport" || continue
+
+		start_instance "$brport"
+	done
+}
+
+start_service() {
+	[ "`uci get mldpoker.@general[0].disabled 2> /dev/null`" = "1" ] && exit 0
+
+	if [ $# -eq 0 ]; then
+		start_all_instances
+	elif [ $# -gt 0 ] && [ -n "$1" ]; then
+		start_instance "$1"
+	else
+		echo "Error: Unknown start command: $@" >&2
+		exit 1
+	fi
+}
+
+stop_instance() {
+	procd_kill mldpoker mldpoker-$1
+}
+
+stop_all_instances() {
+	local brport
+
+	for brport in /sys/class/net/*/brport/; do
+		brport=${brport%/*/}
+		brport=${brport##*/}
+
+		br_is_querier "$brport" || continue
+
+		stop_instance "$brport"
+	done
+}
+
+stop_service() {
+	if [ $# -eq 0 ]; then
+		stop_all_instances
+	elif [ $# -gt 0 ] && [ -n "$1" ]; then
+		stop_instance "$1"
+	else
+		echo "Error: Unknown stop command: $@" >&2
+		exit 1
+	fi
+}