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Commit bf5d68c7 authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Daniel Borkmann
Browse files

tools: add selftest for BPF_F_ZERO_SEED 



Check that iterating two separate hash maps produces the same
order of keys if BPF_F_ZERO_SEED is used.

Signed-off-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 608114e4

tools/testing/selftests/bpf/test_maps.c

+55 −9
Original line number Diff line number Diff line
@@ -258,24 +258,36 @@ static void test_hashmap_percpu(int task, void *data) 
	close(fd);

}



static void test_hashmap_walk(int task, void *data)

static int helper_fill_hashmap(int max_entries)

{

	int fd, i, max_entries = 1000;

	long long key, value, next_key;

	bool next_key_valid = true;

	int i, fd, ret;

	long long key, value;



	fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(key), sizeof(value),

			    max_entries, map_flags);

	if (fd < 0) {

		printf("Failed to create hashmap '%s'!\n", strerror(errno));

		exit(1);

	}

	CHECK(fd < 0,

	      "failed to create hashmap",

	      "err: %s, flags: 0x%x\n", strerror(errno), map_flags);



	for (i = 0; i < max_entries; i++) {

		key = i; value = key;

		assert(bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST) == 0);

		ret = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);

		CHECK(ret != 0,

		      "can't update hashmap",

		      "err: %s\n", strerror(ret));

	}



	return fd;

}



static void test_hashmap_walk(int task, void *data)

{

	int fd, i, max_entries = 1000;

	long long key, value, next_key;

	bool next_key_valid = true;



	fd = helper_fill_hashmap(max_entries);



	for (i = 0; bpf_map_get_next_key(fd, !i ? NULL : &key,

					 &next_key) == 0; i++) {

		key = next_key;
@@ -306,6 +318,39 @@ static void test_hashmap_walk(int task, void *data) 
	close(fd);

}



static void test_hashmap_zero_seed(void)

{

	int i, first, second, old_flags;

	long long key, next_first, next_second;



	old_flags = map_flags;

	map_flags |= BPF_F_ZERO_SEED;



	first = helper_fill_hashmap(3);

	second = helper_fill_hashmap(3);



	for (i = 0; ; i++) {

		void *key_ptr = !i ? NULL : &key;



		if (bpf_map_get_next_key(first, key_ptr, &next_first) != 0)

			break;



		CHECK(bpf_map_get_next_key(second, key_ptr, &next_second) != 0,

		      "next_key for second map must succeed",

		      "key_ptr: %p", key_ptr);

		CHECK(next_first != next_second,

		      "keys must match",

		      "i: %d first: %lld second: %lld\n", i,

		      next_first, next_second);



		key = next_first;

	}



	map_flags = old_flags;

	close(first);

	close(second);

}



static void test_arraymap(int task, void *data)

{

	int key, next_key, fd;
@@ -1534,6 +1579,7 @@ static void run_all_tests(void) 
	test_hashmap(0, NULL);

	test_hashmap_percpu(0, NULL);

	test_hashmap_walk(0, NULL);

	test_hashmap_zero_seed();



	test_arraymap(0, NULL);

	test_arraymap_percpu(0, NULL);