Teach SQM hotplug tricks

Some interfaces like wan-pppoe go away, when the ppp connection is lost
and get recreated once the link is established again. SQM now
has its own hotplug script to re-enable itself on the interfae just hotplugged.
SQM will not touch other instances of itself running on other interfaces
if called by hotplug.d. The implementation now allows this functionality by
calling run.sh like:
/usr/lib/sqm/run.sh interface YOUR_INTERFACE_NAME_HERE
e.g.: /usr/lib/sqm/run.sh interface ge00-pppoe
If called with a specific interface SQM will only try to disable itself
on that interface to clean up all left over state and the re-enable
itself on just that interface. Hopefully that allows for better service
with instable interfaces like pppoe. The current code passes a simple manual
stop start test of the ge00-pppoe interface from the GUI and does seem
to do the right thing, at least on cerowrt 3.10.50-1...

net/sqm-scripts/Makefile

@@ -8,8 +8,8 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=sqm-scripts
-PKG_VERSION:=7
-PKG_RELEASE:=3
+PKG_VERSION:=8
+PKG_RELEASE:=1
 PKG_LICENSE:=GPLv2
 
 PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)
@@ -46,6 +46,8 @@ endef
 define Package/sqm-scripts/install
 	$(INSTALL_DIR) $(1)/etc/init.d
 	$(INSTALL_BIN) ./files/etc/init.d/sqm $(1)/etc/init.d/sqm
+	$(INSTALL_DIR) $(1)/etc/hotplug.d/iface
+	$(INSTALL_BIN) ./files/etc/hotplug.d/iface/11-sqm $(1)/etc/hotplug.d/iface/11-sqm
 	$(INSTALL_DIR) $(1)/etc/config
 	$(INSTALL_DATA) ./files/etc/config/sqm $(1)/etc/config/sqm
 	$(INSTALL_DIR) $(1)/usr/lib/sqm

net/sqm-scripts/files/etc/hotplug.d/iface/11-sqm

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+# teach SQM to re-enable itself when an interface re-appears
+logger -t SQM -s "hotplug on interface: ${DEVICE} action: ${ACTION}"
+
+[ "$ACTION" = ifup ] && /usr/lib/sqm/run.sh interface ${DEVICE}
+

net/sqm-scripts/files/usr/lib/sqm/run.sh

@@ -9,16 +9,37 @@
 
 . /lib/functions.sh
 
-STOP=$1
+STOP=
 ACTIVE_STATE_PREFIX="SQM_active_on_"
 ACTIVE_STATE_FILE_DIR="/var/run/SQM"
 mkdir -p ${ACTIVE_STATE_FILE_DIR}
+PROTO_STATE_FILE_LIST=$( ls ${ACTIVE_STATE_FILE_DIR}/${ACTIVE_STATE_PREFIX}* 2> /dev/null )
+
+
+case ${1} in
+    stop)
+        logger -t SQM -s "run.sh stop"
+	STOP=$1
+        ;;
+    interface)
+	START_ON_IF=$2	# only process this interface
+	logger -t SQM -s "Re/starting sqm on interface ${START_ON_IF}"
+	# TODO if $2 is empty just bail...
+	if [ -z ${START_ON_IF} ] ;
+	then
+	    logger -t SQM -s "Interface name missing, nothing to do, bailing out"
+	    return 0
+	fi
+	# only try to restart the just hotplugged interface, so reduce the list of interfaces to stop to the specified one
+	PROTO_STATE_FILE_LIST=${ACTIVE_STATE_FILE_DIR}/${ACTIVE_STATE_PREFIX}${START_ON_IF}
+	;;
+esac
+
 
 # the current uci config file does not necessarily contain sections for all interfaces with active
 # SQM instances, so use the ACTIVE_STATE_FILES to detect the interfaces on which to stop SQM.
 # Currently the .qos scripts start with stopping any existing traffic shaping so this should not
 # effectively change anything...
-PROTO_STATE_FILE_LIST=$( ls ${ACTIVE_STATE_FILE_DIR}/${ACTIVE_STATE_PREFIX}* 2> /dev/null )
 for STATE_FILE in ${PROTO_STATE_FILE_LIST} ; do
     if [ -f ${STATE_FILE} ] ;
     then
@@ -35,6 +56,11 @@ config_load sqm
 run_simple_qos() {
 	local section="$1"
 	export IFACE=$(config_get "$section" interface)
+
+	# If called explicitly for one interface only , so ignore anything else
+	[ -n "${START_ON_IF}" -a "$START_ON_IF" != "$IFACE" ] && return
+	#logger -t SQM -s "marching on..."
+
 	ACTIVE_STATE_FILE_FQN="${ACTIVE_STATE_FILE_DIR}/${ACTIVE_STATE_PREFIX}${IFACE}"	# this marks interfaces as active with SQM
 	[ -f "${ACTIVE_STATE_FILE_FQN}" ] && logger -t SQM -s "Uh, oh, ${ACTIVE_STATE_FILE_FQN} should already be stopped."	# Not supposed to happen
 

net/sqm-scripts/files/usr/lib/sqm/simple.qos

@@ -37,6 +37,9 @@ ipt -t mangle -A QOS_MARK_${IFACE} -m tos  --tos Minimize-Delay -j MARK --set-ma
 
 # Turn it on. Preserve classification if already performed
 
+#sm: is it correct to do this in $IFACE? Should ingress not be on $DEV? since HTB acts on $DEV?
+#	SQUASH also does not work on $DEV (that is the IFB will still see the incoming ToS bits whether we squash or not)
+#	SQUASH is still useful to protect internal machines...
 if [ "$SQUASH_DSCP" = "1" ]
 then
 sqm_logger "Squashing differentiated services code points (DSCP) from ingress."