[PATCH bpf-next v3 4/4] selftests/bpf: Add tests for attaching XDP programs

["Toke Høiland-Jørgensen" <toke@redhat.com>]

From: Toke Høiland-Jørgensen <toke@redhat.com>

This adds tests for the various replacement operations using
IFLA_XDP_EXPECTED_ID.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
 .../testing/selftests/bpf/prog_tests/xdp_attach.c  |   74 ++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_attach.c

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
new file mode 100644
index 000000000000..190df7599107
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+
+#define IFINDEX_LO 1
+#define XDP_FLAGS_EXPECT_ID		(1U << 4)
+
+void test_xdp_attach(void)
+{
+	struct bpf_object *obj1, *obj2, *obj3;
+	const char *file = "./test_xdp.o";
+	struct bpf_prog_info info = {};
+	__u32 duration = 0, id1, id2;
+	__u32 len = sizeof(info);
+	int err, fd1, fd2, fd3;
+	DECLARE_LIBBPF_OPTS(bpf_xdp_set_link_opts, opts);
+
+	err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj1, &fd1);
+	if (CHECK_FAIL(err))
+		return;
+	err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj2, &fd2);
+	if (CHECK_FAIL(err))
+		goto out_1;
+	err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj3, &fd3);
+	if (CHECK_FAIL(err))
+		goto out_2;
+
+	err = bpf_obj_get_info_by_fd(fd1, &info, &len);
+	if (CHECK_FAIL(err))
+		goto out_2;
+	id1 = info.id;
+
+	memset(&info, 0, sizeof(info));
+	err = bpf_obj_get_info_by_fd(fd2, &info, &len);
+	if (CHECK_FAIL(err))
+		goto out_2;
+	id2 = info.id;
+
+	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd1, XDP_FLAGS_EXPECT_ID,
+				       &opts);
+	if (CHECK(err, "load_ok", "initial load failed"))
+		goto out_close;
+
+	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd2, XDP_FLAGS_EXPECT_ID,
+				       &opts);
+	if (CHECK(!err, "load_fail", "load with expected id didn't fail"))
+		goto out;
+
+	opts.old_id = id1;
+	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd2, 0, &opts);
+	if (CHECK(err, "replace_ok", "replace valid old_id failed"))
+		goto out;
+
+	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd3, 0, &opts);
+	if (CHECK(!err, "replace_fail", "replace invalid old_id didn't fail"))
+		goto out;
+
+	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, 0, &opts);
+	if (CHECK(!err, "remove_fail", "remove invalid old_id didn't fail"))
+		goto out;
+
+	opts.old_id = id2;
+	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, 0, &opts);
+	if (CHECK(err, "remove_ok", "remove valid old_id failed"))
+		goto out;
+
+out:
+	bpf_set_link_xdp_fd(IFINDEX_LO, -1, 0);
+out_close:
+	bpf_object__close(obj3);
+out_2:
+	bpf_object__close(obj2);
+out_1:
+	bpf_object__close(obj1);
+}