/*
* Randomized tests for eBPF longest-prefix-match maps
*
* This program runs randomized tests against the lpm-bpf-map. It implements a
* "Trivial Longest Prefix Match" (tlpm) based on simple, linear, singly linked
* lists. The implementation should be pretty straightforward.
*
* Based on tlpm, this inserts randomized data into bpf-lpm-maps and verifies
* the trie-based bpf-map implementation behaves the same way as tlpm.
*/
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <linux/bpf.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <bpf/bpf.h>
#include "bpf_util.h"
struct tlpm_node {
struct tlpm_node *next;
size_t n_bits;
uint8_t key[];
};
static struct tlpm_node *tlpm_add(struct tlpm_node *list,
const uint8_t *key,
size_t n_bits)
{
struct tlpm_node *node;
size_t n;
/* add new entry with @key/@n_bits to @list and return new head */
n = (n_bits + 7) / 8;
node = malloc(sizeof(*node) + n);
assert(node);
node->next = list;
node->n_bits = n_bits;
memcpy(node->key, key, n);
return node;
}
static void tlpm_clear(struct tlpm_node *list)
{
struct tlpm_node *node;
/* free all entries in @list */
while ((node = list)) {
list = list->next;
free(node);
}
}
static struct tlpm_node *tlpm_match(struct tlpm_node *list,
const uint8_t *key,
size_t n_bits)
{
struct tlpm_node *best = NULL;
size_t i;
/* Perform longest prefix-match on @key/@n_bits. That is, iterate all
* entries and match each prefix against @key. Remember the "best"
* entry we find (i.e., the longest prefix that matches) and return it
* to the caller when done.
*/
for ( ; list; list = list->next) {
for (i = 0; i < n_bits && i < list->n_bits; ++i) {
if ((key[i / 8] & (1 << (7 - i % 8))) !=
(list->key[i / 8] & (1 << (7 - i % 8))))
break;
}
if (i >= list->n_bits) {
if (!best || i > best->n_bits)
best = list;
}
}
return best;
}
static void test_lpm_basic(void)
{
struct tlpm_node *list = NULL, *t1, *t2;
/* very basic, static tests to verify tlpm works as expected */
assert(!tlpm_match(list, (uint8_t[]){ 0xff }, 8));
t1 = list = tlpm_add(list, (uint8_t[]){ 0xff }, 8);
assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff }, 8));
assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 16));
assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0x00 }, 16));
assert(!tlpm_match(list, (uint8_t[]){ 0x7f }, 8));
assert(!tlpm_match(list, (uint8_t[]){ 0xfe }, 8));
assert(!tlpm_match(list, (uint8_t[]){ 0xff }, 7));
t2 = list = tlpm_add(list, (uint8_t[]){ 0xff, 0xff }, 16);
assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff }, 8));
assert(t2 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 16));
assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 15));
assert(!tlpm_match(list, (uint8_t[]){ 0x7f, 0xff }, 16));
tlpm_clear(list);
}
static void test_lpm_order(void)
{
struct tlpm_node *t1, *t2, *l1 = NULL, *l2 = NULL;
size_t i, j;
/* Verify the tlpm implementation works correctly regardless of the
* order of entries. Insert a random set of entries into @l1, and copy
* the same data in reverse order into @l2. Then verify a lookup of
* random keys will yield the same result in both sets.
*/
for (i = 0; i < (1 << 12); ++i)
l1 = tlpm_add(l1, (uint8_t[]){
rand() % 0xff,
rand() % 0xff,
}, rand() % 16 + 1);
for (t1 = l1; t1; t1 = t1->next)
l2 = tlpm_add(l2, t1->key, t1->n_bits);
for (i = 0; i < (1 << 8); ++i) {
uint8_t key[] = { rand() % 0xff, rand() % 0xff };
t1 = tlpm_match(l1, key, 16);
t2 = tlpm_match(l2, key, 16);
assert(!t1 == !t2);
if (t1) {
assert(t1->n_bits == t2->n_bits);
for (j = 0; j < t1->n_bits; ++j)
assert((t1->key[j / 8] & (1 << (7 - j % 8))) ==
(t2->key[j / 8] & (1 << (7 - j % 8))));
}
}
tlpm_clear(l1);
tlpm_clear(l2);
}
static void test_lpm_map(int keysize)
{
size_t i, j, n_matches, n_nodes, n_lookups;
struct tlpm_node *t, *list = NULL;
struct bpf_lpm_trie_key *key;
uint8_t *data, *value;
int r, map;
/* Compare behavior of tlpm vs. bpf-lpm. Create a randomized set of
* prefixes and insert it into both tlpm and bpf-lpm. Then run some
* randomized lookups and verify both maps return the same result.
*/
n_matches = 0;
n_nodes = 1 << 8;
n_lookups = 1 << 16;
data = alloca(keysize);
memset(data, 0, keysize);
value = alloca(keysize + 1);
memset(value, 0, keysize + 1);
key = alloca(sizeof(*key) + keysize);
memset(key, 0, sizeof(*key) + keysize);
map = bpf_create_map(BPF_MAP_TYPE_LPM_TRIE,
sizeof(*key) + keysize,
keysize + 1,
4096,
BPF_F_NO_PREALLOC);
assert(map >= 0);
for (i = 0; i < n_nodes; ++i) {
for (j = 0; j < keysize; ++j)
value[j] = rand() & 0xff;
value[keysize] = rand() % (8 * keysize + 1);
list = tlpm_add(list, value, value[keysize]);
key->prefixlen = value[keysize];
memcpy(key->data, value, keysize);
r = bpf_map_update_elem(map, key, value, 0);
assert(!r);
}
for (i = 0; i < n_lookups; ++i) {
for (j = 0; j < keysize; ++j)
data[j] = rand() & 0xff;
t = tlpm_match(list, data, 8 * keysize);
key->prefixlen = 8 * keysize;
memcpy(key->data, data, keysize);
r = bpf_map_lookup_elem(map, key, value);
assert(!r || errno == ENOENT);
assert(!t == !!r);
if (t) {
++n_matches;
assert(t->n_bits == value[keysize]);
for (j = 0; j < t->n_bits; ++j)
assert((t->key[j / 8] & (1 << (7 - j % 8))) ==
(value[j / 8] & (1 << (7 - j % 8))));
}
}
close(map);
tlpm_clear(list);
/* With 255 random nodes in the map, we are pretty likely to match
* something on every lookup. For statistics, use this:
*
* printf(" nodes: %zu\n"
* "lookups: %zu\n"
* "matches: %zu\n", n_nodes, n_lookups, n_matches);
*/
}
/* Test the implementation with some 'real world' examples */
static void test_lpm_ipaddr(void)
{
struct bpf_lpm_trie_key *key_ipv4;
struct bpf_lpm_trie_key *key_ipv6;
size_t key_size_ipv4;
size_t key_size_ipv6;
int map_fd_ipv4;
int map_fd_ipv6;
__u64 value;
key_size_ipv4 = sizeof(*key_ipv4) + sizeof(__u32);
key_size_ipv6 = sizeof(*key_ipv6) + sizeof(__u32) * 4;
key_ipv4 = alloca(key_size_ipv4);
key_ipv6 = alloca(key_size_ipv6);
map_fd_ipv4 = bpf_create_map(BPF_MAP_TYPE_LPM_TRIE,
key_size_ipv4, sizeof(value),
100, BPF_F_NO_PREALLOC);
assert(map_fd_ipv4 >= 0);
map_fd_ipv6 = bpf_create_map(BPF_MAP_TYPE_LPM_TRIE,
key_size_ipv6, sizeof(value),
100, BPF_F_NO_PREALLOC);
assert(map_fd_ipv6 >= 0);
/* Fill data some IPv4 and IPv6 address ranges */
value = 1;
key_ipv4->prefixlen = 16;
inet_pton(AF_INET, "192.168.0.0", key_ipv4->data);
assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
value = 2;
key_ipv4->prefixlen = 24;
inet_pton(AF_INET, "192.168.0.0", key_ipv4->data);
assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
value = 3;
key_ipv4->prefixlen = 24;
inet_pton(AF_INET, "192.168.128.0", key_ipv4->data);
assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
value = 5;
key_ipv4->prefixlen = 24;
inet_pton(AF_INET, "192.168.1.0", key_ipv4->data);
assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
value = 4;
key_ipv4->prefixlen = 23;
inet_pton(AF_INET, "192.168.0.0", key_ipv4->data);
assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
value = 0xdeadbeef;
key_ipv6->prefixlen = 64;
inet_pton(AF_INET6, "2a00:1450:4001:814::200e", key_ipv6->data);
assert(bpf_map_update_elem(map_fd_ipv6, key_ipv6, &value, 0) == 0);
/* Set tprefixlen to maximum for lookups */
key_ipv4->prefixlen = 32;
key_ipv6->prefixlen = 128;
/* Test some lookups that should come back with a value */
inet_pton(AF_INET, "192.168.128.23", key_ipv4->data);
assert(bpf_map_lookup_elem(map_fd_ipv4, key_ipv4, &value) == 0);
assert(value == 3);
inet_pton(AF_INET, "192.168.0.1", key_ipv4->data);
assert(bpf_map_lookup_elem(map_fd_ipv4, key_ipv4, &value) == 0);
assert(value == 2);
inet_pton(AF_INET6, "2a00:1450:4001:814::", key_ipv6->data);
assert(bpf_map_lookup_elem(map_fd_ipv6, key_ipv6, &value) == 0);
assert(value == 0xdeadbeef);
inet_pton(AF_INET6, "2a00:1450:4001:814::1", key_ipv6->data);
assert(bpf_map_lookup_elem(map_fd_ipv6, key_ipv6, &value) == 0);
assert(value == 0xdeadbeef);
/* Test some lookups that should not match any entry */
inet_pton(AF_INET, "10.0.0.1", key_ipv4->data);
assert(bpf_map_lookup_elem(map_fd_ipv4, key_ipv4, &value) == -1 &&
errno == ENOENT);
inet_pton(AF_INET, "11.11.11.11", key_ipv4->data);
assert(bpf_map_lookup_elem(map_fd_ipv4, key_ipv4, &value) == -1 &&
errno == ENOENT);
inet_pton(AF_INET6, "2a00:ffff::", key_ipv6->data);
assert(bpf_map_lookup_elem(map_fd_ipv6, key_ipv6, &value) == -1 &&
errno == ENOENT);
close(map_fd_ipv4);
close(map_fd_ipv6);
}
int main(void)
{
struct rlimit limit = { RLIM_INFINITY, RLIM_INFINITY };
int i, ret;
/* we want predictable, pseudo random tests */
srand(0xf00ba1);
/* allow unlimited locked memory */
ret = setrlimit(RLIMIT_MEMLOCK, &limit);
if (ret < 0)
perror("Unable to lift memlock rlimit");
test_lpm_basic();
test_lpm_order();
/* Test with 8, 16, 24, 32, ... 128 bit prefix length */
for (i = 1; i <= 16; ++i)
test_lpm_map(i);
test_lpm_ipaddr();
printf("test_lpm: OK\n");
return 0;
}
