selftests/bpf: Add BPF ringbuf selftests

Both singleton BPF ringbuf and BPF ringbuf with map-in-map use cases are tested.
Also reserve+submit/discards and output variants of API are validated.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200529075424.3139988-4-andriin@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 77 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
new file mode 100644
index 000000000000..edf3b6953533
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct sample {
+	int pid;
+	int seq;
+	long value;
+	char comm[16];
+};
+
+struct ringbuf_map {
+	__uint(type, BPF_MAP_TYPE_RINGBUF);
+	__uint(max_entries, 1 << 12);
+} ringbuf1 SEC(".maps"),
+  ringbuf2 SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
+	__uint(max_entries, 4);
+	__type(key, int);
+	__array(values, struct ringbuf_map);
+} ringbuf_arr SEC(".maps") = {
+	.values = {
+		[0] = &ringbuf1,
+		[2] = &ringbuf2,
+	},
+};
+
+/* inputs */
+int pid = 0;
+int target_ring = 0;
+long value = 0;
+
+/* outputs */
+long total = 0;
+long dropped = 0;
+long skipped = 0;
+
+SEC("tp/syscalls/sys_enter_getpgid")
+int test_ringbuf(void *ctx)
+{
+	int cur_pid = bpf_get_current_pid_tgid() >> 32;
+	struct sample *sample;
+	void *rb;
+	int zero = 0;
+
+	if (cur_pid != pid)
+		return 0;
+
+	rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring);
+	if (!rb) {
+		skipped += 1;
+		return 1;
+	}
+
+	sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0);
+	if (!sample) {
+		dropped += 1;
+		return 1;
+	}
+
+	sample->pid = pid;
+	bpf_get_current_comm(sample->comm, sizeof(sample->comm));
+	sample->value = value;
+
+	sample->seq = total;
+	total += 1;
+
+	bpf_ringbuf_submit(sample, 0);
+
+	return 0;
+}