// SPDX-License-Identifier: GPL-2.0
#include "bpf/libbpf.h"
#include "changes_pkt_data_freplace.skel.h"
#include "changes_pkt_data.skel.h"
#include <test_progs.h>

static void print_verifier_log(const char *log)
{
	if (env.verbosity >= VERBOSE_VERY)
		fprintf(stdout, "VERIFIER LOG:\n=============\n%s=============\n", log);
}

static void test_aux(const char *main_prog_name,
		     const char *to_be_replaced,
		     const char *replacement,
		     bool expect_load)
{
	struct changes_pkt_data_freplace *freplace = NULL;
	struct bpf_program *freplace_prog = NULL;
	struct bpf_program *main_prog = NULL;
	LIBBPF_OPTS(bpf_object_open_opts, opts);
	struct changes_pkt_data *main = NULL;
	char log[16*1024];
	int err;

	opts.kernel_log_buf = log;
	opts.kernel_log_size = sizeof(log);
	if (env.verbosity >= VERBOSE_SUPER)
		opts.kernel_log_level = 1 | 2 | 4;
	main = changes_pkt_data__open_opts(&opts);
	if (!ASSERT_OK_PTR(main, "changes_pkt_data__open"))
		goto out;
	main_prog = bpf_object__find_program_by_name(main->obj, main_prog_name);
	if (!ASSERT_OK_PTR(main_prog, "main_prog"))
		goto out;
	bpf_program__set_autoload(main_prog, true);
	err = changes_pkt_data__load(main);
	print_verifier_log(log);
	if (!ASSERT_OK(err, "changes_pkt_data__load"))
		goto out;
	freplace = changes_pkt_data_freplace__open_opts(&opts);
	if (!ASSERT_OK_PTR(freplace, "changes_pkt_data_freplace__open"))
		goto out;
	freplace_prog = bpf_object__find_program_by_name(freplace->obj, replacement);
	if (!ASSERT_OK_PTR(freplace_prog, "freplace_prog"))
		goto out;
	bpf_program__set_autoload(freplace_prog, true);
	bpf_program__set_autoattach(freplace_prog, true);
	bpf_program__set_attach_target(freplace_prog,
				       bpf_program__fd(main_prog),
				       to_be_replaced);
	err = changes_pkt_data_freplace__load(freplace);
	print_verifier_log(log);
	if (expect_load) {
		ASSERT_OK(err, "changes_pkt_data_freplace__load");
	} else {
		ASSERT_ERR(err, "changes_pkt_data_freplace__load");
		ASSERT_HAS_SUBSTR(log, "Extension program changes packet data", "error log");
	}

out:
	changes_pkt_data_freplace__destroy(freplace);
	changes_pkt_data__destroy(main);
}

/* There are two global subprograms in both changes_pkt_data.skel.h:
 * - one changes packet data;
 * - another does not.
 * It is ok to freplace subprograms that change packet data with those
 * that either do or do not. It is only ok to freplace subprograms
 * that do not change packet data with those that do not as well.
 * The below tests check outcomes for each combination of such freplace.
 * Also test a case when main subprogram itself is replaced and is a single
 * subprogram in a program.
 */
void test_changes_pkt_data_freplace(void)
{
	struct {
		const char *main;
		const char *to_be_replaced;
		bool changes;
	} mains[] = {
		{ "main_with_subprogs",   "changes_pkt_data",         true },
		{ "main_with_subprogs",   "does_not_change_pkt_data", false },
		{ "main_changes",         "main_changes",             true },
		{ "main_does_not_change", "main_does_not_change",     false },
	};
	struct {
		const char *func;
		bool changes;
	} replacements[] = {
		{ "changes_pkt_data",         true },
		{ "does_not_change_pkt_data", false }
	};
	char buf[64];

	for (int i = 0; i < ARRAY_SIZE(mains); ++i) {
		for (int j = 0; j < ARRAY_SIZE(replacements); ++j) {
			snprintf(buf, sizeof(buf), "%s_with_%s",
				 mains[i].to_be_replaced, replacements[j].func);
			if (!test__start_subtest(buf))
				continue;
			test_aux(mains[i].main, mains[i].to_be_replaced, replacements[j].func,
				 mains[i].changes || !replacements[j].changes);
		}
	}
}