bpf: Test deletion in BPF_MAP_TYPE_LPM_TRIE

Extend the 'random' operation tests to include a delete operation
(delete half of the nodes from both lpm implementions and ensure
that lookups are still equivalent).

Also, add a simple IPv4 test which verifies lookup behavior as nodes
are deleted from the tree.

Signed-off-by: Craig Gallek <kraig@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/tools/testing/selftests/bpf/test_lpm_map.c b/tools/testing/selftests/bpf/test_lpm_map.c
index a5ed7c4..6fedb9f 100644 (file)
--- a/tools/testing/selftests/bpf/test_lpm_map.c
+++ b/tools/testing/selftests/bpf/test_lpm_map.c
@@ -104,6 +104,34 @@ static struct tlpm_node *tlpm_match(struct tlpm_node *list,
        return best;
 }
 
+static struct tlpm_node *tlpm_delete(struct tlpm_node *list,
+                                    const uint8_t *key,
+                                    size_t n_bits)
+{
+       struct tlpm_node *best = tlpm_match(list, key, n_bits);
+       struct tlpm_node *node;
+
+       if (!best || best->n_bits != n_bits)
+               return list;
+
+       if (best == list) {
+               node = best->next;
+               free(best);
+               return node;
+       }
+
+       for (node = list; node; node = node->next) {
+               if (node->next == best) {
+                       node->next = best->next;
+                       free(best);
+                       return list;
+               }
+       }
+       /* should never get here */
+       assert(0);
+       return list;
+}
+
 static void test_lpm_basic(void)
 {
        struct tlpm_node *list = NULL, *t1, *t2;
@@ -126,6 +154,13 @@ static void test_lpm_basic(void)
        assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 15));
        assert(!tlpm_match(list, (uint8_t[]){ 0x7f, 0xff }, 16));
 
+       list = tlpm_delete(list, (uint8_t[]){ 0xff, 0xff }, 16);
+       assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff }, 8));
+       assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 16));
+
+       list = tlpm_delete(list, (uint8_t[]){ 0xff }, 8);
+       assert(!tlpm_match(list, (uint8_t[]){ 0xff }, 8));
+
        tlpm_clear(list);
 }
 
@@ -170,7 +205,7 @@ static void test_lpm_order(void)
 
 static void test_lpm_map(int keysize)
 {
-       size_t i, j, n_matches, n_nodes, n_lookups;
+       size_t i, j, n_matches, n_matches_after_delete, n_nodes, n_lookups;
        struct tlpm_node *t, *list = NULL;
        struct bpf_lpm_trie_key *key;
        uint8_t *data, *value;
@@ -182,6 +217,7 @@ static void test_lpm_map(int keysize)
         */
 
        n_matches = 0;
+       n_matches_after_delete = 0;
        n_nodes = 1 << 8;
        n_lookups = 1 << 16;
 
@@ -235,15 +271,54 @@ static void test_lpm_map(int keysize)
                }
        }
 
+       /* Remove the first half of the elements in the tlpm and the
+        * corresponding nodes from the bpf-lpm.  Then run the same
+        * large number of random lookups in both and make sure they match.
+        * Note: we need to count the number of nodes actually inserted
+        * since there may have been duplicates.
+        */
+       for (i = 0, t = list; t; i++, t = t->next)
+               ;
+       for (j = 0; j < i / 2; ++j) {
+               key->prefixlen = list->n_bits;
+               memcpy(key->data, list->key, keysize);
+               r = bpf_map_delete_elem(map, key);
+               assert(!r);
+               list = tlpm_delete(list, list->key, list->n_bits);
+               assert(list);
+       }
+       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_after_delete;
+                       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);
+        *     printf("          nodes: %zu\n"
+        *            "        lookups: %zu\n"
+        *            "        matches: %zu\n"
+        *            "matches(delete): %zu\n",
+        *            n_nodes, n_lookups, n_matches, n_matches_after_delete);
         */
 }
 
@@ -343,6 +418,108 @@ static void test_lpm_ipaddr(void)
        close(map_fd_ipv6);
 }
 
+static void test_lpm_delete(void)
+{
+       struct bpf_lpm_trie_key *key;
+       size_t key_size;
+       int map_fd;
+       __u64 value;
+
+       key_size = sizeof(*key) + sizeof(__u32);
+       key = alloca(key_size);
+
+       map_fd = bpf_create_map(BPF_MAP_TYPE_LPM_TRIE,
+                               key_size, sizeof(value),
+                               100, BPF_F_NO_PREALLOC);
+       assert(map_fd >= 0);
+
+       /* Add nodes:
+        * 192.168.0.0/16   (1)
+        * 192.168.0.0/24   (2)
+        * 192.168.128.0/24 (3)
+        * 192.168.1.0/24   (4)
+        *
+        *         (1)
+        *        /   \
+         *     (IM)    (3)
+        *    /   \
+         *   (2)  (4)
+        */
+       value = 1;
+       key->prefixlen = 16;
+       inet_pton(AF_INET, "192.168.0.0", key->data);
+       assert(bpf_map_update_elem(map_fd, key, &value, 0) == 0);
+
+       value = 2;
+       key->prefixlen = 24;
+       inet_pton(AF_INET, "192.168.0.0", key->data);
+       assert(bpf_map_update_elem(map_fd, key, &value, 0) == 0);
+
+       value = 3;
+       key->prefixlen = 24;
+       inet_pton(AF_INET, "192.168.128.0", key->data);
+       assert(bpf_map_update_elem(map_fd, key, &value, 0) == 0);
+
+       value = 4;
+       key->prefixlen = 24;
+       inet_pton(AF_INET, "192.168.1.0", key->data);
+       assert(bpf_map_update_elem(map_fd, key, &value, 0) == 0);
+
+       /* remove non-existent node */
+       key->prefixlen = 32;
+       inet_pton(AF_INET, "10.0.0.1", key->data);
+       assert(bpf_map_lookup_elem(map_fd, key, &value) == -1 &&
+               errno == ENOENT);
+
+       /* assert initial lookup */
+       key->prefixlen = 32;
+       inet_pton(AF_INET, "192.168.0.1", key->data);
+       assert(bpf_map_lookup_elem(map_fd, key, &value) == 0);
+       assert(value == 2);
+
+       /* remove leaf node */
+       key->prefixlen = 24;
+       inet_pton(AF_INET, "192.168.0.0", key->data);
+       assert(bpf_map_delete_elem(map_fd, key) == 0);
+
+       key->prefixlen = 32;
+       inet_pton(AF_INET, "192.168.0.1", key->data);
+       assert(bpf_map_lookup_elem(map_fd, key, &value) == 0);
+       assert(value == 1);
+
+       /* remove leaf (and intermediary) node */
+       key->prefixlen = 24;
+       inet_pton(AF_INET, "192.168.1.0", key->data);
+       assert(bpf_map_delete_elem(map_fd, key) == 0);
+
+       key->prefixlen = 32;
+       inet_pton(AF_INET, "192.168.1.1", key->data);
+       assert(bpf_map_lookup_elem(map_fd, key, &value) == 0);
+       assert(value == 1);
+
+       /* remove root node */
+       key->prefixlen = 16;
+       inet_pton(AF_INET, "192.168.0.0", key->data);
+       assert(bpf_map_delete_elem(map_fd, key) == 0);
+
+       key->prefixlen = 32;
+       inet_pton(AF_INET, "192.168.128.1", key->data);
+       assert(bpf_map_lookup_elem(map_fd, key, &value) == 0);
+       assert(value == 3);
+
+       /* remove last node */
+       key->prefixlen = 24;
+       inet_pton(AF_INET, "192.168.128.0", key->data);
+       assert(bpf_map_delete_elem(map_fd, key) == 0);
+
+       key->prefixlen = 32;
+       inet_pton(AF_INET, "192.168.128.1", key->data);
+       assert(bpf_map_lookup_elem(map_fd, key, &value) == -1 &&
+               errno == ENOENT);
+
+       close(map_fd);
+}
+
 int main(void)
 {
        struct rlimit limit  = { RLIM_INFINITY, RLIM_INFINITY };
@@ -365,6 +542,8 @@ int main(void)
 
        test_lpm_ipaddr();
 
+       test_lpm_delete();
+
        printf("test_lpm: OK\n");
        return 0;
 }