[PATCH v2 net-next 3/3] selftests:net: Implement ptp4l sync test using netdevsim

[Maciek Machnikowski <maciek@machnikowski.net>]

Add PTP synchronization test using ptp4l and netdevsim.

The test creates two netdevsim adapters, links them together
and runs the ptp4l leader and ptp4l follower on two ends
of the netdevsim link and waits for the follower to report the
synchronized state (s2) in its output log.

This implementation runs the test runs over IPv4 link.

Signed-off-by: Maciek Machnikowski <maciek@machnikowski.net>
---
 tools/testing/selftests/net/ptp.sh | 93 ++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100755 tools/testing/selftests/net/ptp.sh

diff --git a/tools/testing/selftests/net/ptp.sh b/tools/testing/selftests/net/ptp.sh
new file mode 100755
index 000000000..8b1604b96
--- /dev/null
+++ b/tools/testing/selftests/net/ptp.sh
@@ -0,0 +1,93 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+source lib.sh
+
+NSIM_DEV_1_ID=$((256 + RANDOM % 256))
+NSIM_DEV_2_ID=$((512 + RANDOM % 256))
+
+NSIM_DEV_SYS_LINK=/sys/bus/netdevsim/link_device
+NSIM_DEV_SYS_UNLINK=/sys/bus/netdevsim/unlink_device
+PTP4L_SYNC_TIMEOUT=20
+
+setup_netdevsim()
+{
+	set -e
+	ip netns add nssv
+	ip netns add nscl
+
+	NSIM_DEV_1_NAME=$(create_netdevsim $NSIM_DEV_1_ID nssv)
+	NSIM_DEV_2_NAME=$(create_netdevsim $NSIM_DEV_2_ID nscl)
+
+	ip netns exec nssv ip addr add '192.168.1.1/24' dev $NSIM_DEV_1_NAME
+	ip netns exec nscl ip addr add '192.168.1.2/24' dev $NSIM_DEV_2_NAME
+
+	set +e
+}
+
+cleanup()
+{
+	[ -n "${PTP4L_LEADER_PID-}" ] && {
+		kill $PTP4L_LEADER_PID $PTP4L_FOLLOWER_PID 2>/dev/null
+		wait $PTP4L_LEADER_PID $PTP4L_FOLLOWER_PID 2>/dev/null
+		rm -f "$PTP4L_LEADER_LOG" "$PTP4L_FOLLOWER_LOG"
+	}
+
+	[ -n "${NSIM_DEV_1_FD-}" ] && [ -n "${NSIM_DEV_1_IFIDX-}" ] && \
+		echo "$NSIM_DEV_1_FD:$NSIM_DEV_1_IFIDX" > "$NSIM_DEV_SYS_UNLINK" 2>/dev/null
+	cleanup_netdevsim "${NSIM_DEV_2_ID-}" 2>/dev/null
+	cleanup_netdevsim "${NSIM_DEV_1_ID-}" 2>/dev/null
+
+	ip netns del nscl 2>/dev/null
+	ip netns del nssv 2>/dev/null
+
+	modprobe -r netdevsim 2>/dev/null
+}
+
+###
+### Code start
+###
+if [ ! -x "$(command -v ptp4l)" ]; then
+	echo "ptp4l command not found. Skipping PTP sync test"
+	exit 4
+fi
+
+trap cleanup EXIT
+
+setup_netdevsim
+
+# Link netdevsim1 with netdevsim2
+NSIM_DEV_1_FD=$((256 + RANDOM % 256))
+exec {NSIM_DEV_1_FD}</var/run/netns/nssv
+NSIM_DEV_1_IFIDX=$(ip netns exec nssv cat /sys/class/net/$NSIM_DEV_1_NAME/ifindex)
+
+NSIM_DEV_2_FD=$((512 + RANDOM % 256))
+exec {NSIM_DEV_2_FD}</var/run/netns/nscl
+NSIM_DEV_2_IFIDX=$(ip netns exec nscl cat /sys/class/net/$NSIM_DEV_2_NAME/ifindex)
+
+if ! echo "$NSIM_DEV_1_FD:$NSIM_DEV_1_IFIDX $NSIM_DEV_2_FD:$NSIM_DEV_2_IFIDX" > "$NSIM_DEV_SYS_LINK"; then
+	echo "linking netdevsim1 with netdevsim2 failed"
+	exit 1
+fi
+
+# PTP synchronization test: run ptp4l leader in nssv and follower in nscl,
+# then parse follower output to verify they synchronized (servo state s2 = locked).
+PTP4L_LEADER_LOG=$(mktemp)
+PTP4L_FOLLOWER_LOG=$(mktemp)
+ip netns exec nssv ptp4l -i "$NSIM_DEV_1_NAME" -m -4 -P \
+	> "$PTP4L_LEADER_LOG" 2>&1 &
+PTP4L_LEADER_PID=$!
+
+ip netns exec nscl ptp4l -i "$NSIM_DEV_2_NAME" -s -m -4 -P \
+	> "$PTP4L_FOLLOWER_LOG" 2>&1 &
+PTP4L_FOLLOWER_PID=$!
+
+
+for _ in $(seq 1 $PTP4L_SYNC_TIMEOUT); do
+	if grep -q ' s2 ' "$PTP4L_FOLLOWER_LOG" 2>/dev/null; then
+		exit 0
+	fi
+	sleep 1
+done
+
+echo "ptp4l follower did not reach locked state (s2) within ${PTP4L_SYNC_TIMEOUT}s"
+exit 1
\ No newline at end of file
-- 
2.53.0