[PATCH bpf-next 3/3] selftests/bpf: add tests for bpf_dynptr_copy

[Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>]

From: Mykyta Yatsenko <yatsenko@meta.com>

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: Mykyta Yatsenko <yatsenko@meta.com>
---
 tools/testing/selftests/bpf/bpf_kfuncs.h      |  8 ++
 .../testing/selftests/bpf/prog_tests/dynptr.c | 25 ++++++
 .../selftests/bpf/progs/dynptr_success.c      | 77 +++++++++++++++++++
 3 files changed, 110 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_kfuncs.h b/tools/testing/selftests/bpf/bpf_kfuncs.h
index 8215c9b3115e..e9c193036c82 100644
--- a/tools/testing/selftests/bpf/bpf_kfuncs.h
+++ b/tools/testing/selftests/bpf/bpf_kfuncs.h
@@ -43,6 +43,14 @@ extern bool bpf_dynptr_is_rdonly(const struct bpf_dynptr *ptr) __ksym __weak;
 extern __u32 bpf_dynptr_size(const struct bpf_dynptr *ptr) __ksym __weak;
 extern int bpf_dynptr_clone(const struct bpf_dynptr *ptr, struct bpf_dynptr *clone__init) __ksym __weak;
 
+/* Description
+ *  Copy data from one dynptr to another
+ * Returns
+ *  Error code
+ */
+extern int bpf_dynptr_copy(struct bpf_dynptr *dst, __u32 dst_off,
+			   struct bpf_dynptr *src, __u32 src_off, __u32 size) __ksym __weak;
+
 /* Description
  *  Modify the address of a AF_UNIX sockaddr.
  * Returns
diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c
index b614a5272dfd..247618958155 100644
--- a/tools/testing/selftests/bpf/prog_tests/dynptr.c
+++ b/tools/testing/selftests/bpf/prog_tests/dynptr.c
@@ -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 +123,28 @@ 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);
+		if (!ASSERT_GE(prog_fd, 0, "prog_fd"))
+			goto cleanup;
+
+		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");
diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c
index bfcc85686cf0..8a6b35418e39 100644
--- a/tools/testing/selftests/bpf/progs/dynptr_success.c
+++ b/tools/testing/selftests/bpf/progs/dynptr_success.c
@@ -567,3 +567,80 @@ int BPF_PROG(test_dynptr_skb_tp_btf, void *skb, void *location)
 
 	return 1;
 }
+
+SEC("?tp/syscalls/sys_enter_nanosleep")
+int test_dynptr_copy(void *ctx)
+{
+	char *data = "hello there, world!!";
+	char buf[32] = {'\0'};
+	__u32 sz = strlen(data);
+	struct bpf_dynptr src, dst;
+
+	bpf_ringbuf_reserve_dynptr(&ringbuf, sz, 0, &src);
+	bpf_ringbuf_reserve_dynptr(&ringbuf, sz, 0, &dst);
+
+	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 ?: __builtin_memcmp(data, buf, sz);
+
+	err = err ?: bpf_dynptr_copy(&dst, 3, &src, 5, sz - 5);
+	err = err ?: bpf_dynptr_read(buf, sz - 5, &dst, 3, 0);
+	err = err ?: __builtin_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 = strlen(data);
+	int i, chunks = 200;
+
+	bpf_dynptr_from_xdp(xdp, 0, &ptr_xdp);
+	bpf_ringbuf_reserve_dynptr(&ringbuf, len * chunks, 0, &ptr_buf);
+
+	bpf_for(i, 0, chunks) {
+		err =  err ?: bpf_dynptr_write(&ptr_buf, i * len, data, len, 0);
+	}
+
+	err = err ?: bpf_dynptr_copy(&ptr_xdp, 0, &ptr_buf, 0, len * chunks);
+
+	bpf_for(i, 0, chunks) {
+		memset(buf, 0, sizeof(buf));
+		err = err ?: bpf_dynptr_read(&buf, len, &ptr_xdp, i * len, 0);
+		err = err ?: memcmp(data, buf, len);
+	}
+
+	memset(buf, 0, sizeof(buf));
+	bpf_for(i, 0, chunks) {
+		err = err ?: bpf_dynptr_write(&ptr_buf, i * len, buf, len, 0);
+	}
+
+	err = err ?: bpf_dynptr_copy(&ptr_buf, 0, &ptr_xdp, 0, len * chunks);
+
+	bpf_for(i, 0, chunks) {
+		memset(buf, 0, sizeof(buf));
+		err = err ?: bpf_dynptr_read(&buf, len, &ptr_buf, i * len, 0);
+		err = err ?: memcmp(data, buf, len);
+	}
+
+	bpf_ringbuf_discard_dynptr(&ptr_buf, 0);
+
+	err = err ?: bpf_dynptr_copy(&ptr_xdp, 2, &ptr_xdp, len, len * (chunks - 1));
+
+	bpf_for(i, 0, chunks - 1) {
+		memset(buf, 0, sizeof(buf));
+		err = err ?: bpf_dynptr_read(&buf, len, &ptr_xdp, 2 + i * len, 0);
+		err = err ?: memcmp(data, buf, len);
+	}
+
+	err = err ?: (bpf_dynptr_copy(&ptr_xdp, 2000, &ptr_xdp, 0, len * chunks) == -E2BIG ? 0 : 1);
+
+	return XDP_DROP;
+}
-- 
2.48.1