selftests: net: tsn_lib: allow running ptp4l on multiple interfaces

Switch ports will want to act as Boundary Clocks, which are configured
using ptp4l by specifying the "-i" argument multiple times.

Since we track a log file and a pid file for each ptp4l instance, and we
want to be compatible with the existing single-port callers of
ptp4l_start and ptp4l_stop, pass the interface list as a single string
of space-separated values. Based on this, we create a label for each
ptp4l instance, where the spaces are replaced with underscores
(ptp4l_start "eth0 eth1" generates "ptp4l_pid_eth0_eth1").

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/forwarding/tsn_lib.sh

@@ -53,15 +53,27 @@ phc2sys_stop()
 	rm "${phc2sys_log}" 2> /dev/null
 }
 
+# Replace space separators from interface list with underscores
+if_names_to_label()
+{
+	local if_name_list="$1"
+
+	echo "${if_name_list/ /_}"
+}
+
 ptp4l_start()
 {
-	local if_name=$1
+	local if_names="$1"
 	local slave_only=$2
 	local uds_address=$3
-	local log="ptp4l_log_${if_name}"
-	local pid="ptp4l_pid_${if_name}"
+	local log="ptp4l_log_$(if_names_to_label ${if_names})"
+	local pid="ptp4l_pid_$(if_names_to_label ${if_names})"
 	local extra_args=""
 
+	for if_name in ${if_names}; do
+		extra_args="${extra_args} -i ${if_name}"
+	done
+
 	if [ "${slave_only}" = true ]; then
 		extra_args="${extra_args} -s"
 	fi
@@ -71,7 +83,6 @@ ptp4l_start()
 	declare -g "${log}=$(mktemp)"
 
 	chrt -f 10 ptp4l -m -2 -P \
-		-i ${if_name} \
 		--step_threshold 0.00002 \
 		--first_step_threshold 0.00002 \
 		--tx_timestamp_timeout 100 \
@@ -80,16 +91,16 @@ ptp4l_start()
 		> "${!log}" 2>&1 &
 	declare -g "${pid}=$!"
 
-	echo "ptp4l for interface ${if_name} logs to ${!log} and has pid ${!pid}"
+	echo "ptp4l for interfaces ${if_names} logs to ${!log} and has pid ${!pid}"
 
 	sleep 1
 }
 
 ptp4l_stop()
 {
-	local if_name=$1
-	local log="ptp4l_log_${if_name}"
-	local pid="ptp4l_pid_${if_name}"
+	local if_names="$1"
+	local log="ptp4l_log_$(if_names_to_label ${if_names})"
+	local pid="ptp4l_pid_$(if_names_to_label ${if_names})"
 
 	{ kill ${!pid} && wait ${!pid}; } 2> /dev/null
 	rm "${!log}" 2> /dev/null