Commit 64e15820 authored by Kurt Kanzenbach's avatar Kurt Kanzenbach Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add BPF-helper test for CLOCK_TAI access 



Add BPF-helper test case for CLOCK_TAI access. The added test verifies that:

 * Timestamps are generated
 * Timestamps are moving forward
 * Timestamps are reasonable

Signed-off-by: default avatarKurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20220809060803.5773-3-kurt@linutronix.de


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c8996c98

tools/testing/selftests/bpf/prog_tests/time_tai.c

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (C) 2022 Linutronix GmbH */



#include <test_progs.h>

#include <network_helpers.h>



#include "test_time_tai.skel.h"



#include <time.h>

#include <stdint.h>



#define TAI_THRESHOLD	1000000000ULL /* 1s */

#define NSEC_PER_SEC	1000000000ULL



static __u64 ts_to_ns(const struct timespec *ts)

{

	return ts->tv_sec * NSEC_PER_SEC + ts->tv_nsec;

}



void test_time_tai(void)

{

	struct __sk_buff skb = {

		.cb[0] = 0,

		.cb[1] = 0,

		.tstamp = 0,

	};

	LIBBPF_OPTS(bpf_test_run_opts, topts,

		.data_in = &pkt_v4,

		.data_size_in = sizeof(pkt_v4),

		.ctx_in = &skb,

		.ctx_size_in = sizeof(skb),

		.ctx_out = &skb,

		.ctx_size_out = sizeof(skb),

	);

	struct test_time_tai *skel;

	struct timespec now_tai;

	__u64 ts1, ts2, now;

	int ret, prog_fd;



	/* Open and load */

	skel = test_time_tai__open_and_load();

	if (!ASSERT_OK_PTR(skel, "tai_open"))

		return;



	/* Run test program */

	prog_fd = bpf_program__fd(skel->progs.time_tai);

	ret = bpf_prog_test_run_opts(prog_fd, &topts);

	ASSERT_OK(ret, "test_run");



	/* Retrieve generated TAI timestamps */

	ts1 = skb.tstamp;

	ts2 = skb.cb[0] | ((__u64)skb.cb[1] << 32);



	/* TAI != 0 */

	ASSERT_NEQ(ts1, 0, "tai_ts1");

	ASSERT_NEQ(ts2, 0, "tai_ts2");



	/* TAI is moving forward only */

	ASSERT_GT(ts2, ts1, "tai_forward");



	/* Check for future */

	ret = clock_gettime(CLOCK_TAI, &now_tai);

	ASSERT_EQ(ret, 0, "tai_gettime");

	now = ts_to_ns(&now_tai);



	ASSERT_TRUE(now > ts1, "tai_future_ts1");

	ASSERT_TRUE(now > ts2, "tai_future_ts2");



	/* Check for reasonable range */

	ASSERT_TRUE(now - ts1 < TAI_THRESHOLD, "tai_range_ts1");

	ASSERT_TRUE(now - ts2 < TAI_THRESHOLD, "tai_range_ts2");



	test_time_tai__destroy(skel);

}

tools/testing/selftests/bpf/progs/test_time_tai.c

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (C) 2022 Linutronix GmbH */



#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>



char _license[] SEC("license") = "GPL";



SEC("tc")

int time_tai(struct __sk_buff *skb)

{

	__u64 ts1, ts2;



	/* Get TAI timestamps */

	ts1 = bpf_ktime_get_tai_ns();

	ts2 = bpf_ktime_get_tai_ns();



	/* Save TAI timestamps (Note: skb->hwtstamp is read-only) */

	skb->tstamp = ts1;

	skb->cb[0] = ts2 & 0xffffffff;

	skb->cb[1] = ts2 >> 32;



	return 0;

}