selftests/bpf: Add tests for attaching XDP programs

// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>

#define IFINDEX_LO 1

#define XDP_FLAGS_REPLACE		(1U << 4)

void test_xdp_attach(void)

{

	struct bpf_object *obj1, *obj2, *obj3;

	const char *file = "./test_xdp.o";

	int err, fd1, fd2, fd3;

	__u32 duration = 0;

	DECLARE_LIBBPF_OPTS(bpf_xdp_set_link_opts, opts,

			    .old_fd = -1);

	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_set_link_xdp_fd_opts(IFINDEX_LO, fd1, XDP_FLAGS_REPLACE,

				       &opts);

	if (CHECK(err, "load_ok", "initial load failed"))

		goto out_close;

	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd2, XDP_FLAGS_REPLACE,

				       &opts);

	if (CHECK(!err, "load_fail", "load with expected id didn't fail"))

		goto out;

	opts.old_fd = fd1;

	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd2, 0, &opts);

	if (CHECK(err, "replace_ok", "replace valid old_fd failed"))

		goto out;

	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, fd3, 0, &opts);

	if (CHECK(!err, "replace_fail", "replace invalid old_fd 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_fd didn't fail"))

		goto out;

	opts.old_fd = fd2;

	err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, 0, &opts);

	if (CHECK(err, "remove_ok", "remove valid old_fd 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);

}