selftests/bpf: Add more test cases for LPM trie

Add more test cases for LPM trie in test_maps:

1) test_lpm_trie_update_flags
It constructs various use cases for BPF_EXIST and BPF_NOEXIST and check
whether the return value of update operation is expected.

2) test_lpm_trie_update_full_maps
It tests the update operations on a full LPM trie map. Adding new node
will fail and overwriting the value of existed node will succeed.

3) test_lpm_trie_iterate_strs and test_lpm_trie_iterate_ints
There two test cases test whether the iteration through get_next_key is
sorted and expected. These two test cases delete the minimal key after
each iteration and check whether next iteration returns the second
minimal key. The only difference between these two test cases is the
former one saves strings in the LPM trie and the latter saves integers.
Without the fix of get_next_key, these two cases will fail as shown
below:
test_lpm_trie_iterate_strs(1091):FAIL:iterate #2 got abc exp abS
test_lpm_trie_iterate_ints(1142):FAIL:iterate #1 got 0x2 exp 0x1

Signed-off-by: Hou Tao <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/testing/selftests/bpf/map_tests/lpm_trie_map_basic_ops.c

···
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
+#include <endian.h>
 #include <arpa/inet.h>
 #include <sys/time.h>
 
 #include <bpf/bpf.h>
+#include <test_maps.h>
 
 #include "bpf_util.h"
 
···
 	struct tlpm_node *next;
 	size_t n_bits;
 	uint8_t key[];
+};
+
+struct lpm_trie_bytes_key {
+	union {
+		struct bpf_lpm_trie_key_hdr hdr;
+		__u32 prefixlen;
+	};
+	unsigned char data[8];
+};
+
+struct lpm_trie_int_key {
+	union {
+		struct bpf_lpm_trie_key_hdr hdr;
+		__u32 prefixlen;
+	};
+	unsigned int data;
 };
 
 static struct tlpm_node *tlpm_match(struct tlpm_node *list,
···
 	close(map_fd);
 }
 
+static int lpm_trie_create(unsigned int key_size, unsigned int value_size, unsigned int max_entries)
+{
+	LIBBPF_OPTS(bpf_map_create_opts, opts);
+	int fd;
+
+	opts.map_flags = BPF_F_NO_PREALLOC;
+	fd = bpf_map_create(BPF_MAP_TYPE_LPM_TRIE, "lpm_trie", key_size, value_size, max_entries,
+			    &opts);
+	CHECK(fd < 0, "bpf_map_create", "error %d\n", errno);
+
+	return fd;
+}
+
+static void test_lpm_trie_update_flags(void)
+{
+	struct lpm_trie_int_key key;
+	unsigned int value, got;
+	int fd, err;
+
+	fd = lpm_trie_create(sizeof(key), sizeof(value), 3);
+
+	/* invalid flags (Error) */
+	key.prefixlen = 32;
+	key.data = 0;
+	value = 0;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_F_LOCK);
+	CHECK(err != -EINVAL, "invalid update flag", "error %d\n", err);
+
+	/* invalid flags (Error) */
+	key.prefixlen = 32;
+	key.data = 0;
+	value = 0;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST | BPF_EXIST);
+	CHECK(err != -EINVAL, "invalid update flag", "error %d\n", err);
+
+	/* overwrite an empty qp-trie (Error) */
+	key.prefixlen = 32;
+	key.data = 0;
+	value = 2;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_EXIST);
+	CHECK(err != -ENOENT, "overwrite empty qp-trie", "error %d\n", err);
+
+	/* add a new node */
+	key.prefixlen = 16;
+	key.data = 0;
+	value = 1;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+	CHECK(err, "add new elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup elem", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* add the same node as new node (Error) */
+	err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+	CHECK(err != -EEXIST, "add new elem again", "error %d\n", err);
+
+	/* overwrite the existed node */
+	value = 4;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_EXIST);
+	CHECK(err, "overwrite elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup elem", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* overwrite the node */
+	value = 1;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_ANY);
+	CHECK(err, "update elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup elem", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* overwrite a non-existent node which is the prefix of the first
+	 * node (Error).
+	 */
+	key.prefixlen = 8;
+	key.data = 0;
+	value = 2;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_EXIST);
+	CHECK(err != -ENOENT, "overwrite nonexistent elem", "error %d\n", err);
+
+	/* add a new node which is the prefix of the first node */
+	err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+	CHECK(err, "add new elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup key", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* add another new node which will be the sibling of the first node */
+	key.prefixlen = 9;
+	key.data = htobe32(1 << 23);
+	value = 5;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+	CHECK(err, "add new elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup key", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* overwrite the third node */
+	value = 3;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_ANY);
+	CHECK(err, "overwrite elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup key", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* delete the second node to make it an intermediate node */
+	key.prefixlen = 8;
+	key.data = 0;
+	err = bpf_map_delete_elem(fd, &key);
+	CHECK(err, "del elem", "error %d\n", err);
+
+	/* overwrite the intermediate node (Error) */
+	value = 2;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_EXIST);
+	CHECK(err != -ENOENT, "overwrite nonexistent elem", "error %d\n", err);
+
+	close(fd);
+}
+
+static void test_lpm_trie_update_full_map(void)
+{
+	struct lpm_trie_int_key key;
+	int value, got;
+	int fd, err;
+
+	fd = lpm_trie_create(sizeof(key), sizeof(value), 3);
+
+	/* add a new node */
+	key.prefixlen = 16;
+	key.data = 0;
+	value = 0;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+	CHECK(err, "add new elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup elem", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* add new node */
+	key.prefixlen = 8;
+	key.data = 0;
+	value = 1;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+	CHECK(err, "add new elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup elem", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* add new node */
+	key.prefixlen = 9;
+	key.data = htobe32(1 << 23);
+	value = 2;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+	CHECK(err, "add new elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup elem", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* try to add more node (Error) */
+	key.prefixlen = 32;
+	key.data = 0;
+	value = 3;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_ANY);
+	CHECK(err != -ENOSPC, "add to full trie", "error %d\n", err);
+
+	/* update the value of an existed node with BPF_EXIST */
+	key.prefixlen = 16;
+	key.data = 0;
+	value = 4;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_EXIST);
+	CHECK(err, "overwrite elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup elem", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	/* update the value of an existed node with BPF_ANY */
+	key.prefixlen = 9;
+	key.data = htobe32(1 << 23);
+	value = 5;
+	err = bpf_map_update_elem(fd, &key, &value, BPF_ANY);
+	CHECK(err, "overwrite elem", "error %d\n", err);
+	got = 0;
+	err = bpf_map_lookup_elem(fd, &key, &got);
+	CHECK(err, "lookup elem", "error %d\n", err);
+	CHECK(got != value, "check value", "got %d exp %d\n", got, value);
+
+	close(fd);
+}
+
+static int cmp_str(const void *a, const void *b)
+{
+	const char *str_a = *(const char **)a, *str_b = *(const char **)b;
+
+	return strcmp(str_a, str_b);
+}
+
+/* Save strings in LPM trie. The trailing '\0' for each string will be
+ * accounted in the prefixlen. The strings returned during the iteration
+ * should be sorted as expected.
+ */
+static void test_lpm_trie_iterate_strs(void)
+{
+	static const char * const keys[] = {
+		"ab", "abO", "abc", "abo", "abS", "abcd",
+	};
+	const char *sorted_keys[ARRAY_SIZE(keys)];
+	struct lpm_trie_bytes_key key, next_key;
+	unsigned int value, got, i, j, len;
+	struct lpm_trie_bytes_key *cur;
+	int fd, err;
+
+	fd = lpm_trie_create(sizeof(key), sizeof(value), ARRAY_SIZE(keys));
+
+	for (i = 0; i < ARRAY_SIZE(keys); i++) {
+		unsigned int flags;
+
+		/* add i-th element */
+		flags = i % 2 ? BPF_NOEXIST : 0;
+		len = strlen(keys[i]);
+		/* include the trailing '\0' */
+		key.prefixlen = (len + 1) * 8;
+		memset(key.data, 0, sizeof(key.data));
+		memcpy(key.data, keys[i], len);
+		value = i + 100;
+		err = bpf_map_update_elem(fd, &key, &value, flags);
+		CHECK(err, "add elem", "#%u error %d\n", i, err);
+
+		err = bpf_map_lookup_elem(fd, &key, &got);
+		CHECK(err, "lookup elem", "#%u error %d\n", i, err);
+		CHECK(got != value, "lookup elem", "#%u expect %u got %u\n", i, value, got);
+
+		/* re-add i-th element (Error) */
+		err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+		CHECK(err != -EEXIST, "re-add elem", "#%u error %d\n", i, err);
+
+		/* Overwrite i-th element */
+		flags = i % 2 ? 0 : BPF_EXIST;
+		value = i;
+		err = bpf_map_update_elem(fd, &key, &value, flags);
+		CHECK(err, "update elem", "error %d\n", err);
+
+		/* Lookup #[0~i] elements */
+		for (j = 0; j <= i; j++) {
+			len = strlen(keys[j]);
+			key.prefixlen = (len + 1) * 8;
+			memset(key.data, 0, sizeof(key.data));
+			memcpy(key.data, keys[j], len);
+			err = bpf_map_lookup_elem(fd, &key, &got);
+			CHECK(err, "lookup elem", "#%u/%u error %d\n", i, j, err);
+			CHECK(got != j, "lookup elem", "#%u/%u expect %u got %u\n",
+			      i, j, value, got);
+		}
+	}
+
+	/* Add element to a full qp-trie (Error) */
+	key.prefixlen = sizeof(key.data) * 8;
+	memset(key.data, 0, sizeof(key.data));
+	value = 0;
+	err = bpf_map_update_elem(fd, &key, &value, 0);
+	CHECK(err != -ENOSPC, "add to full qp-trie", "error %d\n", err);
+
+	/* Iterate sorted elements: no deletion */
+	memcpy(sorted_keys, keys, sizeof(keys));
+	qsort(sorted_keys, ARRAY_SIZE(sorted_keys), sizeof(sorted_keys[0]), cmp_str);
+	cur = NULL;
+	for (i = 0; i < ARRAY_SIZE(sorted_keys); i++) {
+		len = strlen(sorted_keys[i]);
+		err = bpf_map_get_next_key(fd, cur, &next_key);
+		CHECK(err, "iterate", "#%u error %d\n", i, err);
+		CHECK(next_key.prefixlen != (len + 1) * 8, "iterate",
+		      "#%u invalid len %u expect %u\n",
+		      i, next_key.prefixlen, (len + 1) * 8);
+		CHECK(memcmp(sorted_keys[i], next_key.data, len + 1), "iterate",
+		      "#%u got %.*s exp %.*s\n", i, len, next_key.data, len, sorted_keys[i]);
+
+		cur = &next_key;
+	}
+	err = bpf_map_get_next_key(fd, cur, &next_key);
+	CHECK(err != -ENOENT, "more element", "error %d\n", err);
+
+	/* Iterate sorted elements: delete the found key after each iteration */
+	cur = NULL;
+	for (i = 0; i < ARRAY_SIZE(sorted_keys); i++) {
+		len = strlen(sorted_keys[i]);
+		err = bpf_map_get_next_key(fd, cur, &next_key);
+		CHECK(err, "iterate", "#%u error %d\n", i, err);
+		CHECK(next_key.prefixlen != (len + 1) * 8, "iterate",
+		      "#%u invalid len %u expect %u\n",
+		      i, next_key.prefixlen, (len + 1) * 8);
+		CHECK(memcmp(sorted_keys[i], next_key.data, len + 1), "iterate",
+		      "#%u got %.*s exp %.*s\n", i, len, next_key.data, len, sorted_keys[i]);
+
+		cur = &next_key;
+
+		err = bpf_map_delete_elem(fd, cur);
+		CHECK(err, "delete", "#%u error %d\n", i, err);
+	}
+	err = bpf_map_get_next_key(fd, cur, &next_key);
+	CHECK(err != -ENOENT, "non-empty qp-trie", "error %d\n", err);
+
+	close(fd);
+}
+
+/* Use the fixed prefixlen (32) and save integers in LPM trie. The iteration of
+ * LPM trie will return these integers in big-endian order, therefore, convert
+ * these integers to big-endian before update. After each iteration, delete the
+ * found key (the smallest integer) and expect the next iteration will return
+ * the second smallest number.
+ */
+static void test_lpm_trie_iterate_ints(void)
+{
+	struct lpm_trie_int_key key, next_key;
+	unsigned int i, max_entries;
+	struct lpm_trie_int_key *cur;
+	unsigned int *data_set;
+	int fd, err;
+	bool value;
+
+	max_entries = 4096;
+	data_set = calloc(max_entries, sizeof(*data_set));
+	CHECK(!data_set, "malloc", "no mem\n");
+	for (i = 0; i < max_entries; i++)
+		data_set[i] = i;
+
+	fd = lpm_trie_create(sizeof(key), sizeof(value), max_entries);
+	value = true;
+	for (i = 0; i < max_entries; i++) {
+		key.prefixlen = 32;
+		key.data = htobe32(data_set[i]);
+
+		err = bpf_map_update_elem(fd, &key, &value, BPF_NOEXIST);
+		CHECK(err, "add elem", "#%u error %d\n", i, err);
+	}
+
+	cur = NULL;
+	for (i = 0; i < max_entries; i++) {
+		err = bpf_map_get_next_key(fd, cur, &next_key);
+		CHECK(err, "iterate", "#%u error %d\n", i, err);
+		CHECK(next_key.prefixlen != 32, "iterate", "#%u invalid len %u\n",
+		      i, next_key.prefixlen);
+		CHECK(be32toh(next_key.data) != data_set[i], "iterate", "#%u got 0x%x exp 0x%x\n",
+		      i, be32toh(next_key.data), data_set[i]);
+		cur = &next_key;
+
+		/*
+		 * Delete the minimal key, the next call of bpf_get_next_key()
+		 * will return the second minimal key.
+		 */
+		err = bpf_map_delete_elem(fd, &next_key);
+		CHECK(err, "del elem", "#%u elem error %d\n", i, err);
+	}
+	err = bpf_map_get_next_key(fd, cur, &next_key);
+	CHECK(err != -ENOENT, "more element", "error %d\n", err);
+
+	err = bpf_map_get_next_key(fd, NULL, &next_key);
+	CHECK(err != -ENOENT, "no-empty qp-trie", "error %d\n", err);
+
+	free(data_set);
+
+	close(fd);
+}
+
 void test_lpm_trie_map_basic_ops(void)
 {
 	int i;
···
 	test_lpm_delete();
 	test_lpm_get_next_key();
 	test_lpm_multi_thread();
+
+	test_lpm_trie_update_flags();
+	test_lpm_trie_update_full_map();
+	test_lpm_trie_iterate_strs();
+	test_lpm_trie_iterate_ints();
 
 	printf("%s: PASS\n", __func__);
 }