selftests: netdevsim: Test psample functionality

Test various aspects of psample functionality over netdevsim and in
particular test that the psample module correctly reports the provided
metadata.

Example:

 # ./psample.sh
 TEST: psample enable / disable                                      [ OK ]
 TEST: psample group number                                          [ OK ]
 TEST: psample metadata                                              [ OK ]
Signed-off-by: NIdo Schimmel <idosch@nvidia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/netdevsim/psample.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# This test is for checking the psample module. It makes use of netdevsim
+# which periodically generates "sampled" packets.
+
+lib_dir=$(dirname $0)/../../../net/forwarding
+
+ALL_TESTS="
+	psample_enable_test
+	psample_group_num_test
+	psample_md_test
+"
+NETDEVSIM_PATH=/sys/bus/netdevsim/
+DEV_ADDR=1337
+DEV=netdevsim${DEV_ADDR}
+DEVLINK_DEV=netdevsim/${DEV}
+SYSFS_NET_DIR=/sys/bus/netdevsim/devices/$DEV/net/
+PSAMPLE_DIR=/sys/kernel/debug/netdevsim/$DEV/psample/
+CAPTURE_FILE=$(mktemp)
+NUM_NETIFS=0
+source $lib_dir/lib.sh
+source $lib_dir/devlink_lib.sh
+
+# Available at https://github.com/Mellanox/libpsample
+require_command psample
+
+psample_capture()
+{
+	rm -f $CAPTURE_FILE
+
+	timeout 2 ip netns exec testns1 psample &> $CAPTURE_FILE
+}
+
+psample_enable_test()
+{
+	RET=0
+
+	echo 1 > $PSAMPLE_DIR/enable
+	check_err $? "Failed to enable sampling when should not"
+
+	echo 1 > $PSAMPLE_DIR/enable 2>/dev/null
+	check_fail $? "Sampling enablement succeeded when should fail"
+
+	psample_capture
+	if [ $(cat $CAPTURE_FILE | wc -l) -eq 0 ]; then
+		check_err 1 "Failed to capture sampled packets"
+	fi
+
+	echo 0 > $PSAMPLE_DIR/enable
+	check_err $? "Failed to disable sampling when should not"
+
+	echo 0 > $PSAMPLE_DIR/enable 2>/dev/null
+	check_fail $? "Sampling disablement succeeded when should fail"
+
+	psample_capture
+	if [ $(cat $CAPTURE_FILE | wc -l) -ne 0 ]; then
+		check_err 1 "Captured sampled packets when should not"
+	fi
+
+	log_test "psample enable / disable"
+}
+
+psample_group_num_test()
+{
+	RET=0
+
+	echo 1234 > $PSAMPLE_DIR/group_num
+	echo 1 > $PSAMPLE_DIR/enable
+
+	psample_capture
+	grep -q -e "group 1234" $CAPTURE_FILE
+	check_err $? "Sampled packets reported with wrong group number"
+
+	# New group number should only be used after disable / enable.
+	echo 4321 > $PSAMPLE_DIR/group_num
+
+	psample_capture
+	grep -q -e "group 4321" $CAPTURE_FILE
+	check_fail $? "Group number changed while sampling is active"
+
+	echo 0 > $PSAMPLE_DIR/enable && echo 1 > $PSAMPLE_DIR/enable
+
+	psample_capture
+	grep -q -e "group 4321" $CAPTURE_FILE
+	check_err $? "Group number did not change after restarting sampling"
+
+	log_test "psample group number"
+
+	echo 0 > $PSAMPLE_DIR/enable
+}
+
+psample_md_test()
+{
+	RET=0
+
+	echo 1 > $PSAMPLE_DIR/enable
+
+	echo 1234 > $PSAMPLE_DIR/in_ifindex
+	echo 4321 > $PSAMPLE_DIR/out_ifindex
+	psample_capture
+
+	grep -q -e "in-ifindex 1234" $CAPTURE_FILE
+	check_err $? "Sampled packets reported with wrong in-ifindex"
+
+	grep -q -e "out-ifindex 4321" $CAPTURE_FILE
+	check_err $? "Sampled packets reported with wrong out-ifindex"
+
+	echo 5 > $PSAMPLE_DIR/out_tc
+	psample_capture
+
+	grep -q -e "out-tc 5" $CAPTURE_FILE
+	check_err $? "Sampled packets reported with wrong out-tc"
+
+	echo $((2**16 - 1)) > $PSAMPLE_DIR/out_tc
+	psample_capture
+
+	grep -q -e "out-tc " $CAPTURE_FILE
+	check_fail $? "Sampled packets reported with out-tc when should not"
+
+	echo 1 > $PSAMPLE_DIR/out_tc
+	echo 10000 > $PSAMPLE_DIR/out_tc_occ_max
+	psample_capture
+
+	grep -q -e "out-tc-occ " $CAPTURE_FILE
+	check_err $? "Sampled packets not reported with out-tc-occ when should"
+
+	echo 0 > $PSAMPLE_DIR/out_tc_occ_max
+	psample_capture
+
+	grep -q -e "out-tc-occ " $CAPTURE_FILE
+	check_fail $? "Sampled packets reported with out-tc-occ when should not"
+
+	echo 10000 > $PSAMPLE_DIR/latency_max
+	psample_capture
+
+	grep -q -e "latency " $CAPTURE_FILE
+	check_err $? "Sampled packets not reported with latency when should"
+
+	echo 0 > $PSAMPLE_DIR/latency_max
+	psample_capture
+
+	grep -q -e "latency " $CAPTURE_FILE
+	check_fail $? "Sampled packets reported with latency when should not"
+
+	log_test "psample metadata"
+
+	echo 0 > $PSAMPLE_DIR/enable
+}
+
+setup_prepare()
+{
+	modprobe netdevsim &> /dev/null
+
+	echo "$DEV_ADDR 1" > ${NETDEVSIM_PATH}/new_device
+	while [ ! -d $SYSFS_NET_DIR ] ; do :; done
+
+	set -e
+
+	ip netns add testns1
+	devlink dev reload $DEVLINK_DEV netns testns1
+
+	set +e
+}
+
+cleanup()
+{
+	pre_cleanup
+	rm -f $CAPTURE_FILE
+	ip netns del testns1
+	echo "$DEV_ADDR" > ${NETDEVSIM_PATH}/del_device
+	modprobe -r netdevsim &> /dev/null
+}
+
+trap cleanup EXIT
+
+setup_prepare
+
+tests_run
+
+exit $EXIT_STATUS