runners: Expose a 'cleanup' action for silent cleanup of an interface

If a network interface is removed before SQM is stopped on that interface,
removing the qdisc from that interface will result in errors in the log.
Whereas not running the 'stop' action will result in leftover state
files (and possibly an IFB interface).

While the right thing to do would be to stop SQM before removing the
interface, this is not always possible; for instance, pppd doesn't have a
'pre-down' hook. So to accommodate this use case, add a new 'cleanup'
action, which just unwinds the firewall rules, removes the IFB
interface (but silently in case it does not exist), and deletes the state
file.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>

Author: tohojo

platform/linux/sqm-bin

@@ -3,14 +3,20 @@
 . /etc/sqm/sqm.conf
 ACTION="$1"
 RUN_IFACE="$2"
+CLEANUP=0
+
+if [ "$ACTION" = "cleanup" ]; then
+    CLEANUP=1
+    ACTION=stop
+fi
 
 if [ "$(id -u)" -ne "0" ]; then
     echo "This script must be run as root." >&2
     exit 1
 fi
 
 if [ "$ACTION" != "start" -a "$ACTION" != "stop" -a "$ACTION" != "reload" ]; then
-    echo "Usage: $0 <start|stop|reload> [iface]." >&2
+    echo "Usage: $0 <start|stop|reload|cleanup> [iface]." >&2
     exit 1
 fi
 
@@ -20,7 +26,7 @@ if [ "$ACTION" = "stop" -a -z "$RUN_IFACE" ]; then
     for f in ${SQM_STATE_DIR}/*.state; do
         # Source the state file prior to stopping; we need the $IFACE and
         # $SCRIPT variables saved in there.
-        [ -f "$f" ] && ( . $f; IFACE=$IFACE SCRIPT=$SCRIPT SQM_DEBUG=$SQM_DEBUG SQM_DEBUG_LOG=$SQM_DEBUG_LOG OUTPUT_TARGET=$OUTPUT_TARGET ${SQM_LIB_DIR}/stop-sqm )
+        [ -f "$f" ] && ( . $f; IFACE=$IFACE SCRIPT=$SCRIPT CLEANUP=$CLEANUP SQM_DEBUG=$SQM_DEBUG SQM_DEBUG_LOG=$SQM_DEBUG_LOG OUTPUT_TARGET=$OUTPUT_TARGET ${SQM_LIB_DIR}/stop-sqm )
     done
     exit 0
 fi

src/defaults.sh

@@ -104,6 +104,10 @@ fi
 # particular command
 SILENT=0
 
+# If set to 1, stop-sqm will run the (silent) cleanup function instead of a full
+# stop operation
+[ -z "$CLEANUP" ] && CLEANUP=0
+
 # Transaction log for unwinding ipt rules
 IPT_TRANS_LOG="${SQM_STATE_DIR}/${IFACE}.iptables.log"
 

src/run-openwrt.sh

@@ -16,6 +16,12 @@ ACTION="${1:-start}"
 RUN_IFACE="$2"
 LOCKDIR="${SQM_STATE_DIR}/sqm-run.lock"
 
+CLEANUP=0
+if [ "$ACTION" = "cleanup" ]; then
+    CLEANUP=1
+    ACTION=stop
+fi
+
 check_state_dir
 [ -d "${SQM_QDISC_STATE_DIR}" ] || ${SQM_LIB_DIR}/update-available-qdiscs
 
@@ -26,7 +32,7 @@ stop_statefile() {
     # there.
     [ -f "$f" ] && ( . "$f";
                      IFACE=$IFACE SCRIPT=$SCRIPT SQM_DEBUG=$SQM_DEBUG \
-                          SQM_DEBUG_LOG=$SQM_DEBUG_LOG \
+                          SQM_DEBUG_LOG=$SQM_DEBUG_LOG CLEANUP=$CLEANUP \
                           SQM_VERBOSITY_MAX=$SQM_VERBOSITY_MAX \
                           SQM_VERBOSITY_MIN=$SQM_VERBOSITY_MIN \
                           OUTPUT_TARGET=$OUTPUT_TARGET ${SQM_LIB_DIR}/stop-sqm )

src/stop-sqm

@@ -35,7 +35,6 @@ if [ -z "${SCRIPT}" ] ; then
 fi
 
 sqm_trace; sqm_trace "$(date): Stopping." # Add some space and a date stamp to verbose log output and log files to separate runs
-sqm_log "Stopping SQM on ${IFACE}"
 
 # make sure to only delete the ifb associated with the current interface
 CUR_IFB=$( get_ifb_associated_with_if ${IFACE} )
@@ -48,7 +47,13 @@ fi
 
 . "${SQM_LIB_DIR}/$SCRIPT"
 
-sqm_stop
+if [ "$CLEANUP" -eq "1" ]; then
+    sqm_log "Cleaning up SQM state on ${IFACE}"
+    sqm_cleanup 1
+else
+    sqm_log "Stopping SQM on ${IFACE}"
+    sqm_stop
+fi
 rm -f "${STATE_FILE}"
 
 exit 0