selftests: bpf: Test iterating a sockmap

Add a test that exercises a basic sockmap / sockhash iteration. For
now we simply count the number of elements seen. Once sockmap update
from iterators works we can extend this to perform a full copy.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200909162712.221874-4-lmb@cloudflare.com

1 files changed, 43 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c b/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c
new file mode 100644
index 000000000000..0e27f73dd803
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_sockmap.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Cloudflare */
+#include "bpf_iter.h"
+#include "bpf_tracing_net.h"
+#include "bpf_iter_sockmap.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <errno.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+	__uint(type, BPF_MAP_TYPE_SOCKMAP);
+	__uint(max_entries, SOCKMAP_MAX_ENTRIES);
+	__type(key, __u32);
+	__type(value, __u64);
+} sockmap SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_SOCKHASH);
+	__uint(max_entries, SOCKMAP_MAX_ENTRIES);
+	__type(key, __u32);
+	__type(value, __u64);
+} sockhash SEC(".maps");
+
+__u32 elems = 0;
+__u32 socks = 0;
+
+SEC("iter/sockmap")
+int count_elems(struct bpf_iter__sockmap *ctx)
+{
+	struct sock *sk = ctx->sk;
+	__u32 tmp, *key = ctx->key;
+	int ret;
+
+	if (key)
+		elems++;
+
+	if (sk)
+		socks++;
+
+	return 0;
+}