[PATCH bpf-next v4 2/2] selftests: bpf: test BPF_PROG_QUERY for progs attached to sockmap

[Di Zhu]

Add test for querying progs attached to sockmap. we use an existing
libbpf query interface to query prog cnt before and after progs
attaching to sockmap and check whether the queried prog id is right.

Signed-off-by: Di Zhu <zhudi2@xxxxxxxxxx>
---
 .../selftests/bpf/prog_tests/sockmap_basic.c  | 84 +++++++++++++++++++
 .../bpf/progs/test_sockmap_progs_query.c      | 24 ++++++
 2 files changed, 108 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
index 1352ec104149..7f3d5c5da6e1 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
@@ -8,6 +8,7 @@
 #include "test_sockmap_update.skel.h"
 #include "test_sockmap_invalid_update.skel.h"
 #include "test_sockmap_skb_verdict_attach.skel.h"
+#include "test_sockmap_progs_query.skel.h"
 #include "bpf_iter_sockmap.skel.h"
 
 #define TCP_REPAIR		19	/* TCP sock is under repair right now */
@@ -315,6 +316,83 @@ static void test_sockmap_skb_verdict_attach(enum bpf_attach_type first,
 	test_sockmap_skb_verdict_attach__destroy(skel);
 }
 
+static __u32 query_prog_id(int prog)
+{
+	struct bpf_prog_info info = {};
+	__u32 info_len = sizeof(info);
+	int err;
+
+	err = bpf_obj_get_info_by_fd(prog, &info, &info_len);
+	if (CHECK_FAIL(err || info_len != sizeof(info))) {
+		perror("bpf_obj_get_info_by_fd");
+		return 0;
+	}
+
+	return info.id;
+}
+
+static void test_sockmap_progs_query(enum bpf_attach_type attach_type)
+{
+	struct test_sockmap_progs_query *skel;
+	int err, map, verdict, duration = 0;
+	__u32 attach_flags = 0;
+	__u32 prog_ids[3] = {};
+	__u32 prog_cnt = 3;
+
+	skel = test_sockmap_progs_query__open_and_load();
+	if (CHECK_FAIL(!skel)) {
+		perror("test_sockmap_progs_query__open_and_load");
+		return;
+	}
+
+	map = bpf_map__fd(skel->maps.sock_map);
+
+	if (attach_type == BPF_SK_MSG_VERDICT)
+		verdict = bpf_program__fd(skel->progs.prog_skmsg_verdict);
+	else
+		verdict = bpf_program__fd(skel->progs.prog_skb_verdict);
+
+	err = bpf_prog_query(map, attach_type, 0 /* query flags */,
+			     &attach_flags, prog_ids, &prog_cnt);
+	if (CHECK(err, "bpf_prog_query", "failed\n"))
+		goto out;
+
+	if (CHECK(attach_flags != 0, "bpf_prog_query",
+		  "wrong attach_flags on query: %u", attach_flags))
+		goto out;
+
+	if (CHECK(prog_cnt != 0, "bpf_prog_query",
+		  "wrong program count on query: %u", prog_cnt))
+		goto out;
+
+	err = bpf_prog_attach(verdict, map, attach_type, 0);
+	if (CHECK(err, "bpf_prog_attach", "failed\n"))
+		goto out;
+
+	prog_cnt = 1;
+	err = bpf_prog_query(map, attach_type, 0 /* query flags */,
+			     &attach_flags, prog_ids, &prog_cnt);
+	if (CHECK(err, "bpf_prog_query", "failed\n"))
+		goto detach;
+
+	if (CHECK(attach_flags != 0, "bpf_prog_query attach_flags",
+		  "wrong attach_flags on query: %u", attach_flags))
+		goto detach;
+
+	if (CHECK(prog_cnt != 1, "bpf_prog_query prog_cnt",
+		  "wrong program count on query: %u", prog_cnt))
+		goto detach;
+
+	if (CHECK(prog_ids[0] != query_prog_id(verdict), "bpf_prog_query",
+		  "wrong prog_ids on query: %u", prog_ids[0]))
+		goto detach;
+
+detach:
+	bpf_prog_detach2(verdict, map, attach_type);
+out:
+	test_sockmap_progs_query__destroy(skel);
+}
+
 void test_sockmap_basic(void)
 {
 	if (test__start_subtest("sockmap create_update_free"))
@@ -341,4 +419,10 @@ void test_sockmap_basic(void)
 		test_sockmap_skb_verdict_attach(BPF_SK_SKB_STREAM_VERDICT,
 						BPF_SK_SKB_VERDICT);
 	}
+	if (test__start_subtest("sockmap progs query")) {
+		test_sockmap_progs_query(BPF_SK_MSG_VERDICT);
+		test_sockmap_progs_query(BPF_SK_SKB_STREAM_PARSER);
+		test_sockmap_progs_query(BPF_SK_SKB_STREAM_VERDICT);
+		test_sockmap_progs_query(BPF_SK_SKB_VERDICT);
+	}
 }
diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c b/tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c
new file mode 100644
index 000000000000..9d58d61c0dee
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_SOCKMAP);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, __u64);
+} sock_map SEC(".maps");
+
+SEC("sk_skb")
+int prog_skb_verdict(struct __sk_buff *skb)
+{
+	return SK_PASS;
+}
+
+SEC("sk_msg")
+int prog_skmsg_verdict(struct sk_msg_md *msg)
+{
+	return SK_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.27.0