1 /*
2 * Randomized tests for eBPF longest-prefix-match maps
3 *
4 * This program runs randomized tests against the lpm-bpf-map. It implements a
5 * "Trivial Longest Prefix Match" (tlpm) based on simple, linear, singly linked
6 * lists. The implementation should be pretty straightforward.
7 *
8 * Based on tlpm, this inserts randomized data into bpf-lpm-maps and verifies
9 * the trie-based bpf-map implementation behaves the same way as tlpm.
10 */
11
12 #include <assert.h>
13 #include <errno.h>
14 #include <inttypes.h>
15 #include <linux/bpf.h>
16 #include <stdio.h>
17 #include <stdlib.h>
18 #include <string.h>
19 #include <time.h>
20 #include <unistd.h>
21 #include <arpa/inet.h>
22 #include <sys/time.h>
23 #include <sys/resource.h>
24
25 #include <bpf/bpf.h>
26 #include "bpf_util.h"
27
28 struct tlpm_node {
29 struct tlpm_node *next;
30 size_t n_bits;
31 uint8_t key[];
32 };
33
tlpm_add(struct tlpm_node * list,const uint8_t * key,size_t n_bits)34 static struct tlpm_node *tlpm_add(struct tlpm_node *list,
35 const uint8_t *key,
36 size_t n_bits)
37 {
38 struct tlpm_node *node;
39 size_t n;
40
41 /* add new entry with @key/@n_bits to @list and return new head */
42
43 n = (n_bits + 7) / 8;
44 node = malloc(sizeof(*node) + n);
45 assert(node);
46
47 node->next = list;
48 node->n_bits = n_bits;
49 memcpy(node->key, key, n);
50
51 return node;
52 }
53
tlpm_clear(struct tlpm_node * list)54 static void tlpm_clear(struct tlpm_node *list)
55 {
56 struct tlpm_node *node;
57
58 /* free all entries in @list */
59
60 while ((node = list)) {
61 list = list->next;
62 free(node);
63 }
64 }
65
tlpm_match(struct tlpm_node * list,const uint8_t * key,size_t n_bits)66 static struct tlpm_node *tlpm_match(struct tlpm_node *list,
67 const uint8_t *key,
68 size_t n_bits)
69 {
70 struct tlpm_node *best = NULL;
71 size_t i;
72
73 /* Perform longest prefix-match on @key/@n_bits. That is, iterate all
74 * entries and match each prefix against @key. Remember the "best"
75 * entry we find (i.e., the longest prefix that matches) and return it
76 * to the caller when done.
77 */
78
79 for ( ; list; list = list->next) {
80 for (i = 0; i < n_bits && i < list->n_bits; ++i) {
81 if ((key[i / 8] & (1 << (7 - i % 8))) !=
82 (list->key[i / 8] & (1 << (7 - i % 8))))
83 break;
84 }
85
86 if (i >= list->n_bits) {
87 if (!best || i > best->n_bits)
88 best = list;
89 }
90 }
91
92 return best;
93 }
94
test_lpm_basic(void)95 static void test_lpm_basic(void)
96 {
97 struct tlpm_node *list = NULL, *t1, *t2;
98
99 /* very basic, static tests to verify tlpm works as expected */
100
101 assert(!tlpm_match(list, (uint8_t[]){ 0xff }, 8));
102
103 t1 = list = tlpm_add(list, (uint8_t[]){ 0xff }, 8);
104 assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff }, 8));
105 assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 16));
106 assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0x00 }, 16));
107 assert(!tlpm_match(list, (uint8_t[]){ 0x7f }, 8));
108 assert(!tlpm_match(list, (uint8_t[]){ 0xfe }, 8));
109 assert(!tlpm_match(list, (uint8_t[]){ 0xff }, 7));
110
111 t2 = list = tlpm_add(list, (uint8_t[]){ 0xff, 0xff }, 16);
112 assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff }, 8));
113 assert(t2 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 16));
114 assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 15));
115 assert(!tlpm_match(list, (uint8_t[]){ 0x7f, 0xff }, 16));
116
117 tlpm_clear(list);
118 }
119
test_lpm_order(void)120 static void test_lpm_order(void)
121 {
122 struct tlpm_node *t1, *t2, *l1 = NULL, *l2 = NULL;
123 size_t i, j;
124
125 /* Verify the tlpm implementation works correctly regardless of the
126 * order of entries. Insert a random set of entries into @l1, and copy
127 * the same data in reverse order into @l2. Then verify a lookup of
128 * random keys will yield the same result in both sets.
129 */
130
131 for (i = 0; i < (1 << 12); ++i)
132 l1 = tlpm_add(l1, (uint8_t[]){
133 rand() % 0xff,
134 rand() % 0xff,
135 }, rand() % 16 + 1);
136
137 for (t1 = l1; t1; t1 = t1->next)
138 l2 = tlpm_add(l2, t1->key, t1->n_bits);
139
140 for (i = 0; i < (1 << 8); ++i) {
141 uint8_t key[] = { rand() % 0xff, rand() % 0xff };
142
143 t1 = tlpm_match(l1, key, 16);
144 t2 = tlpm_match(l2, key, 16);
145
146 assert(!t1 == !t2);
147 if (t1) {
148 assert(t1->n_bits == t2->n_bits);
149 for (j = 0; j < t1->n_bits; ++j)
150 assert((t1->key[j / 8] & (1 << (7 - j % 8))) ==
151 (t2->key[j / 8] & (1 << (7 - j % 8))));
152 }
153 }
154
155 tlpm_clear(l1);
156 tlpm_clear(l2);
157 }
158
test_lpm_map(int keysize)159 static void test_lpm_map(int keysize)
160 {
161 size_t i, j, n_matches, n_nodes, n_lookups;
162 struct tlpm_node *t, *list = NULL;
163 struct bpf_lpm_trie_key *key;
164 uint8_t *data, *value;
165 int r, map;
166
167 /* Compare behavior of tlpm vs. bpf-lpm. Create a randomized set of
168 * prefixes and insert it into both tlpm and bpf-lpm. Then run some
169 * randomized lookups and verify both maps return the same result.
170 */
171
172 n_matches = 0;
173 n_nodes = 1 << 8;
174 n_lookups = 1 << 16;
175
176 data = alloca(keysize);
177 memset(data, 0, keysize);
178
179 value = alloca(keysize + 1);
180 memset(value, 0, keysize + 1);
181
182 key = alloca(sizeof(*key) + keysize);
183 memset(key, 0, sizeof(*key) + keysize);
184
185 map = bpf_create_map(BPF_MAP_TYPE_LPM_TRIE,
186 sizeof(*key) + keysize,
187 keysize + 1,
188 4096,
189 BPF_F_NO_PREALLOC);
190 assert(map >= 0);
191
192 for (i = 0; i < n_nodes; ++i) {
193 for (j = 0; j < keysize; ++j)
194 value[j] = rand() & 0xff;
195 value[keysize] = rand() % (8 * keysize + 1);
196
197 list = tlpm_add(list, value, value[keysize]);
198
199 key->prefixlen = value[keysize];
200 memcpy(key->data, value, keysize);
201 r = bpf_map_update_elem(map, key, value, 0);
202 assert(!r);
203 }
204
205 for (i = 0; i < n_lookups; ++i) {
206 for (j = 0; j < keysize; ++j)
207 data[j] = rand() & 0xff;
208
209 t = tlpm_match(list, data, 8 * keysize);
210
211 key->prefixlen = 8 * keysize;
212 memcpy(key->data, data, keysize);
213 r = bpf_map_lookup_elem(map, key, value);
214 assert(!r || errno == ENOENT);
215 assert(!t == !!r);
216
217 if (t) {
218 ++n_matches;
219 assert(t->n_bits == value[keysize]);
220 for (j = 0; j < t->n_bits; ++j)
221 assert((t->key[j / 8] & (1 << (7 - j % 8))) ==
222 (value[j / 8] & (1 << (7 - j % 8))));
223 }
224 }
225
226 close(map);
227 tlpm_clear(list);
228
229 /* With 255 random nodes in the map, we are pretty likely to match
230 * something on every lookup. For statistics, use this:
231 *
232 * printf(" nodes: %zu\n"
233 * "lookups: %zu\n"
234 * "matches: %zu\n", n_nodes, n_lookups, n_matches);
235 */
236 }
237
238 /* Test the implementation with some 'real world' examples */
239
test_lpm_ipaddr(void)240 static void test_lpm_ipaddr(void)
241 {
242 struct bpf_lpm_trie_key *key_ipv4;
243 struct bpf_lpm_trie_key *key_ipv6;
244 size_t key_size_ipv4;
245 size_t key_size_ipv6;
246 int map_fd_ipv4;
247 int map_fd_ipv6;
248 __u64 value;
249
250 key_size_ipv4 = sizeof(*key_ipv4) + sizeof(__u32);
251 key_size_ipv6 = sizeof(*key_ipv6) + sizeof(__u32) * 4;
252 key_ipv4 = alloca(key_size_ipv4);
253 key_ipv6 = alloca(key_size_ipv6);
254
255 map_fd_ipv4 = bpf_create_map(BPF_MAP_TYPE_LPM_TRIE,
256 key_size_ipv4, sizeof(value),
257 100, BPF_F_NO_PREALLOC);
258 assert(map_fd_ipv4 >= 0);
259
260 map_fd_ipv6 = bpf_create_map(BPF_MAP_TYPE_LPM_TRIE,
261 key_size_ipv6, sizeof(value),
262 100, BPF_F_NO_PREALLOC);
263 assert(map_fd_ipv6 >= 0);
264
265 /* Fill data some IPv4 and IPv6 address ranges */
266 value = 1;
267 key_ipv4->prefixlen = 16;
268 inet_pton(AF_INET, "192.168.0.0", key_ipv4->data);
269 assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
270
271 value = 2;
272 key_ipv4->prefixlen = 24;
273 inet_pton(AF_INET, "192.168.0.0", key_ipv4->data);
274 assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
275
276 value = 3;
277 key_ipv4->prefixlen = 24;
278 inet_pton(AF_INET, "192.168.128.0", key_ipv4->data);
279 assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
280
281 value = 5;
282 key_ipv4->prefixlen = 24;
283 inet_pton(AF_INET, "192.168.1.0", key_ipv4->data);
284 assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
285
286 value = 4;
287 key_ipv4->prefixlen = 23;
288 inet_pton(AF_INET, "192.168.0.0", key_ipv4->data);
289 assert(bpf_map_update_elem(map_fd_ipv4, key_ipv4, &value, 0) == 0);
290
291 value = 0xdeadbeef;
292 key_ipv6->prefixlen = 64;
293 inet_pton(AF_INET6, "2a00:1450:4001:814::200e", key_ipv6->data);
294 assert(bpf_map_update_elem(map_fd_ipv6, key_ipv6, &value, 0) == 0);
295
296 /* Set tprefixlen to maximum for lookups */
297 key_ipv4->prefixlen = 32;
298 key_ipv6->prefixlen = 128;
299
300 /* Test some lookups that should come back with a value */
301 inet_pton(AF_INET, "192.168.128.23", key_ipv4->data);
302 assert(bpf_map_lookup_elem(map_fd_ipv4, key_ipv4, &value) == 0);
303 assert(value == 3);
304
305 inet_pton(AF_INET, "192.168.0.1", key_ipv4->data);
306 assert(bpf_map_lookup_elem(map_fd_ipv4, key_ipv4, &value) == 0);
307 assert(value == 2);
308
309 inet_pton(AF_INET6, "2a00:1450:4001:814::", key_ipv6->data);
310 assert(bpf_map_lookup_elem(map_fd_ipv6, key_ipv6, &value) == 0);
311 assert(value == 0xdeadbeef);
312
313 inet_pton(AF_INET6, "2a00:1450:4001:814::1", key_ipv6->data);
314 assert(bpf_map_lookup_elem(map_fd_ipv6, key_ipv6, &value) == 0);
315 assert(value == 0xdeadbeef);
316
317 /* Test some lookups that should not match any entry */
318 inet_pton(AF_INET, "10.0.0.1", key_ipv4->data);
319 assert(bpf_map_lookup_elem(map_fd_ipv4, key_ipv4, &value) == -1 &&
320 errno == ENOENT);
321
322 inet_pton(AF_INET, "11.11.11.11", key_ipv4->data);
323 assert(bpf_map_lookup_elem(map_fd_ipv4, key_ipv4, &value) == -1 &&
324 errno == ENOENT);
325
326 inet_pton(AF_INET6, "2a00:ffff::", key_ipv6->data);
327 assert(bpf_map_lookup_elem(map_fd_ipv6, key_ipv6, &value) == -1 &&
328 errno == ENOENT);
329
330 close(map_fd_ipv4);
331 close(map_fd_ipv6);
332 }
333
main(void)334 int main(void)
335 {
336 struct rlimit limit = { RLIM_INFINITY, RLIM_INFINITY };
337 int i, ret;
338
339 /* we want predictable, pseudo random tests */
340 srand(0xf00ba1);
341
342 /* allow unlimited locked memory */
343 ret = setrlimit(RLIMIT_MEMLOCK, &limit);
344 if (ret < 0)
345 perror("Unable to lift memlock rlimit");
346
347 test_lpm_basic();
348 test_lpm_order();
349
350 /* Test with 8, 16, 24, 32, ... 128 bit prefix length */
351 for (i = 1; i <= 16; ++i)
352 test_lpm_map(i);
353
354 test_lpm_ipaddr();
355
356 printf("test_lpm: OK\n");
357 return 0;
358 }
359