// SPDX-License-Identifier: GPL-2.0 /* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #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; }