Commit 064e9aac authored by Mykyta Yatsenko's avatar Mykyta Yatsenko Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add tests for bpf_dynptr_copy 



Add XDP setup type for dynptr tests, enabling testing for
non-contiguous buffer.
Add 2 tests:
 - test_dynptr_copy - verify correctness for the fast (contiguous
 buffer) code path.
 - test_dynptr_copy_xdp - verifies code paths that handle
 non-contiguous buffer.

Signed-off-by: default avatarMykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250226183201.332713-4-mykyta.yatsenko5@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent daec295a

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

+21 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ enum test_setup_type { 
	SETUP_SYSCALL_SLEEP,

	SETUP_SKB_PROG,

	SETUP_SKB_PROG_TP,

	SETUP_XDP_PROG,

};



static struct {
@@ -18,6 +19,8 @@ static struct { 
} success_tests[] = {

	{"test_read_write", SETUP_SYSCALL_SLEEP},

	{"test_dynptr_data", SETUP_SYSCALL_SLEEP},

	{"test_dynptr_copy", SETUP_SYSCALL_SLEEP},

	{"test_dynptr_copy_xdp", SETUP_XDP_PROG},

	{"test_ringbuf", SETUP_SYSCALL_SLEEP},

	{"test_skb_readonly", SETUP_SKB_PROG},

	{"test_dynptr_skb_data", SETUP_SKB_PROG},
@@ -120,6 +123,24 @@ static void verify_success(const char *prog_name, enum test_setup_type setup_typ 


		break;

	}

	case SETUP_XDP_PROG:

	{

		char data[5000];

		int err, prog_fd;

		LIBBPF_OPTS(bpf_test_run_opts, opts,

			    .data_in = &data,

			    .data_size_in = sizeof(data),

			    .repeat = 1,

		);



		prog_fd = bpf_program__fd(prog);

		err = bpf_prog_test_run_opts(prog_fd, &opts);



		if (!ASSERT_OK(err, "test_run"))

			goto cleanup;



		break;

	}

	}



	ASSERT_EQ(skel->bss->err, 0, "err");

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

+118 −5
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2022 Facebook */



#include <vmlinux.h>

#include <string.h>

#include <stdbool.h>

#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "bpf_misc.h"

#include "bpf_kfuncs.h"

#include "errno.h"



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



int pid, err, val;



struct sample {

struct ringbuf_sample {

	int pid;

	int seq;

	long value;
@@ -121,7 +120,7 @@ int test_dynptr_data(void *ctx) 


static int ringbuf_callback(__u32 index, void *data)

{

	struct sample *sample;

	struct ringbuf_sample *sample;



	struct bpf_dynptr *ptr = (struct bpf_dynptr *)data;
@@ -138,7 +137,7 @@ SEC("?tp/syscalls/sys_enter_nanosleep") 
int test_ringbuf(void *ctx)

{

	struct bpf_dynptr ptr;

	struct sample *sample;

	struct ringbuf_sample *sample;



	if (bpf_get_current_pid_tgid() >> 32 != pid)

		return 0;
@@ -567,3 +566,117 @@ int BPF_PROG(test_dynptr_skb_tp_btf, void *skb, void *location) 


	return 1;

}



static inline int bpf_memcmp(const char *a, const char *b, u32 size)

{

	int i;



	bpf_for(i, 0, size) {

		if (a[i] != b[i])

			return a[i] < b[i] ? -1 : 1;

	}

	return 0;

}



SEC("?tp/syscalls/sys_enter_nanosleep")

int test_dynptr_copy(void *ctx)

{

	char data[] = "hello there, world!!";

	char buf[32] = {'\0'};

	__u32 sz = sizeof(data);

	struct bpf_dynptr src, dst;



	bpf_ringbuf_reserve_dynptr(&ringbuf, sz, 0, &src);

	bpf_ringbuf_reserve_dynptr(&ringbuf, sz, 0, &dst);



	/* Test basic case of copying contiguous memory backed dynptrs */

	err = bpf_dynptr_write(&src, 0, data, sz, 0);

	err = err ?: bpf_dynptr_copy(&dst, 0, &src, 0, sz);

	err = err ?: bpf_dynptr_read(buf, sz, &dst, 0, 0);

	err = err ?: bpf_memcmp(data, buf, sz);



	/* Test that offsets are handled correctly */

	err = err ?: bpf_dynptr_copy(&dst, 3, &src, 5, sz - 5);

	err = err ?: bpf_dynptr_read(buf, sz - 5, &dst, 3, 0);

	err = err ?: bpf_memcmp(data + 5, buf, sz - 5);



	bpf_ringbuf_discard_dynptr(&src, 0);

	bpf_ringbuf_discard_dynptr(&dst, 0);

	return 0;

}



SEC("xdp")

int test_dynptr_copy_xdp(struct xdp_md *xdp)

{

	struct bpf_dynptr ptr_buf, ptr_xdp;

	char data[] = "qwertyuiopasdfghjkl";

	char buf[32] = {'\0'};

	__u32 len = sizeof(data);

	int i, chunks = 200;



	/* ptr_xdp is backed by non-contiguous memory */

	bpf_dynptr_from_xdp(xdp, 0, &ptr_xdp);

	bpf_ringbuf_reserve_dynptr(&ringbuf, len * chunks, 0, &ptr_buf);



	/* Destination dynptr is backed by non-contiguous memory */

	bpf_for(i, 0, chunks) {

		err = bpf_dynptr_write(&ptr_buf, i * len, data, len, 0);

		if (err)

			goto out;

	}



	err = bpf_dynptr_copy(&ptr_xdp, 0, &ptr_buf, 0, len * chunks);

	if (err)

		goto out;



	bpf_for(i, 0, chunks) {

		__builtin_memset(buf, 0, sizeof(buf));

		err = bpf_dynptr_read(&buf, len, &ptr_xdp, i * len, 0);

		if (err)

			goto out;

		if (bpf_memcmp(data, buf, len) != 0)

			goto out;

	}



	/* Source dynptr is backed by non-contiguous memory */

	__builtin_memset(buf, 0, sizeof(buf));

	bpf_for(i, 0, chunks) {

		err = bpf_dynptr_write(&ptr_buf, i * len, buf, len, 0);

		if (err)

			goto out;

	}



	err = bpf_dynptr_copy(&ptr_buf, 0, &ptr_xdp, 0, len * chunks);

	if (err)

		goto out;



	bpf_for(i, 0, chunks) {

		__builtin_memset(buf, 0, sizeof(buf));

		err = bpf_dynptr_read(&buf, len, &ptr_buf, i * len, 0);

		if (err)

			goto out;

		if (bpf_memcmp(data, buf, len) != 0)

			goto out;

	}



	/* Both source and destination dynptrs are backed by non-contiguous memory */

	err = bpf_dynptr_copy(&ptr_xdp, 2, &ptr_xdp, len, len * (chunks - 1));

	if (err)

		goto out;



	bpf_for(i, 0, chunks - 1) {

		__builtin_memset(buf, 0, sizeof(buf));

		err = bpf_dynptr_read(&buf, len, &ptr_xdp, 2 + i * len, 0);

		if (err)

			goto out;

		if (bpf_memcmp(data, buf, len) != 0)

			goto out;

	}



	if (bpf_dynptr_copy(&ptr_xdp, 2000, &ptr_xdp, 0, len * chunks) != -E2BIG)

		err = 1;



out:

	bpf_ringbuf_discard_dynptr(&ptr_buf, 0);

	return XDP_DROP;

}