Commit 05526361 authored by Daniel Borkmann's avatar Daniel Borkmann

Merge branch 'bpf-lpm-get-next-key'

Yonghong Song says:

====================
This patch set implements MAP_GET_NEXT_KEY command for LPM_TRIE map.
This command is really useful for key enumeration, and for key deletion
if what keys in the trie are unknown.

Patch #1 implements the functionality in the kernel and patch #2
adds a test case in tools/testing/selftests/bpf.
====================
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parents b7bcc0bb 8c417dc1
......@@ -591,9 +591,100 @@ static void trie_free(struct bpf_map *map)
raw_spin_unlock(&trie->lock);
}
static int trie_get_next_key(struct bpf_map *map, void *key, void *next_key)
static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key)
{
return -ENOTSUPP;
struct lpm_trie *trie = container_of(map, struct lpm_trie, map);
struct bpf_lpm_trie_key *key = _key, *next_key = _next_key;
struct lpm_trie_node *node, *next_node = NULL, *parent;
struct lpm_trie_node **node_stack = NULL;
struct lpm_trie_node __rcu **root;
int err = 0, stack_ptr = -1;
unsigned int next_bit;
size_t matchlen;
/* The get_next_key follows postorder. For the 4 node example in
* the top of this file, the trie_get_next_key() returns the following
* one after another:
* 192.168.0.0/24
* 192.168.1.0/24
* 192.168.128.0/24
* 192.168.0.0/16
*
* The idea is to return more specific keys before less specific ones.
*/
/* Empty trie */
if (!rcu_dereference(trie->root))
return -ENOENT;
/* For invalid key, find the leftmost node in the trie */
if (!key || key->prefixlen > trie->max_prefixlen) {
root = &trie->root;
goto find_leftmost;
}
node_stack = kmalloc(trie->max_prefixlen * sizeof(struct lpm_trie_node *),
GFP_USER | __GFP_NOWARN);
if (!node_stack)
return -ENOMEM;
/* Try to find the exact node for the given key */
for (node = rcu_dereference(trie->root); node;) {
node_stack[++stack_ptr] = node;
matchlen = longest_prefix_match(trie, node, key);
if (node->prefixlen != matchlen ||
node->prefixlen == key->prefixlen)
break;
next_bit = extract_bit(key->data, node->prefixlen);
node = rcu_dereference(node->child[next_bit]);
}
if (!node || node->prefixlen != key->prefixlen ||
(node->flags & LPM_TREE_NODE_FLAG_IM)) {
root = &trie->root;
goto find_leftmost;
}
/* The node with the exactly-matching key has been found,
* find the first node in postorder after the matched node.
*/
node = node_stack[stack_ptr];
while (stack_ptr > 0) {
parent = node_stack[stack_ptr - 1];
if (rcu_dereference(parent->child[0]) == node &&
rcu_dereference(parent->child[1])) {
root = &parent->child[1];
goto find_leftmost;
}
if (!(parent->flags & LPM_TREE_NODE_FLAG_IM)) {
next_node = parent;
goto do_copy;
}
node = parent;
stack_ptr--;
}
/* did not find anything */
err = -ENOENT;
goto free_stack;
find_leftmost:
/* Find the leftmost non-intermediate node, all intermediate nodes
* have exact two children, so this function will never return NULL.
*/
for (node = rcu_dereference(*root); node;) {
if (!(node->flags & LPM_TREE_NODE_FLAG_IM))
next_node = node;
node = rcu_dereference(node->child[0]);
}
do_copy:
next_key->prefixlen = next_node->prefixlen;
memcpy((void *)next_key + offsetof(struct bpf_lpm_trie_key, data),
next_node->data, trie->data_size);
free_stack:
kfree(node_stack);
return err;
}
const struct bpf_map_ops trie_map_ops = {
......
......@@ -521,6 +521,126 @@ static void test_lpm_delete(void)
close(map_fd);
}
static void test_lpm_get_next_key(void)
{
struct bpf_lpm_trie_key *key_p, *next_key_p;
size_t key_size;
__u32 value = 0;
int map_fd;
key_size = sizeof(*key_p) + sizeof(__u32);
key_p = alloca(key_size);
next_key_p = 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);
/* empty tree. get_next_key should return ENOENT */
assert(bpf_map_get_next_key(map_fd, NULL, key_p) == -1 &&
errno == ENOENT);
/* get and verify the first key, get the second one should fail. */
key_p->prefixlen = 16;
inet_pton(AF_INET, "192.168.0.0", key_p->data);
assert(bpf_map_update_elem(map_fd, key_p, &value, 0) == 0);
memset(key_p, 0, key_size);
assert(bpf_map_get_next_key(map_fd, NULL, key_p) == 0);
assert(key_p->prefixlen == 16 && key_p->data[0] == 192 &&
key_p->data[1] == 168);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == -1 &&
errno == ENOENT);
/* no exact matching key should get the first one in post order. */
key_p->prefixlen = 8;
assert(bpf_map_get_next_key(map_fd, NULL, key_p) == 0);
assert(key_p->prefixlen == 16 && key_p->data[0] == 192 &&
key_p->data[1] == 168);
/* add one more element (total two) */
key_p->prefixlen = 24;
inet_pton(AF_INET, "192.168.0.0", key_p->data);
assert(bpf_map_update_elem(map_fd, key_p, &value, 0) == 0);
memset(key_p, 0, key_size);
assert(bpf_map_get_next_key(map_fd, NULL, key_p) == 0);
assert(key_p->prefixlen == 24 && key_p->data[0] == 192 &&
key_p->data[1] == 168 && key_p->data[2] == 0);
memset(next_key_p, 0, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == 0);
assert(next_key_p->prefixlen == 16 && next_key_p->data[0] == 192 &&
next_key_p->data[1] == 168);
memcpy(key_p, next_key_p, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == -1 &&
errno == ENOENT);
/* Add one more element (total three) */
key_p->prefixlen = 24;
inet_pton(AF_INET, "192.168.128.0", key_p->data);
assert(bpf_map_update_elem(map_fd, key_p, &value, 0) == 0);
memset(key_p, 0, key_size);
assert(bpf_map_get_next_key(map_fd, NULL, key_p) == 0);
assert(key_p->prefixlen == 24 && key_p->data[0] == 192 &&
key_p->data[1] == 168 && key_p->data[2] == 0);
memset(next_key_p, 0, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == 0);
assert(next_key_p->prefixlen == 24 && next_key_p->data[0] == 192 &&
next_key_p->data[1] == 168 && next_key_p->data[2] == 128);
memcpy(key_p, next_key_p, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == 0);
assert(next_key_p->prefixlen == 16 && next_key_p->data[0] == 192 &&
next_key_p->data[1] == 168);
memcpy(key_p, next_key_p, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == -1 &&
errno == ENOENT);
/* Add one more element (total four) */
key_p->prefixlen = 24;
inet_pton(AF_INET, "192.168.1.0", key_p->data);
assert(bpf_map_update_elem(map_fd, key_p, &value, 0) == 0);
memset(key_p, 0, key_size);
assert(bpf_map_get_next_key(map_fd, NULL, key_p) == 0);
assert(key_p->prefixlen == 24 && key_p->data[0] == 192 &&
key_p->data[1] == 168 && key_p->data[2] == 0);
memset(next_key_p, 0, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == 0);
assert(next_key_p->prefixlen == 24 && next_key_p->data[0] == 192 &&
next_key_p->data[1] == 168 && next_key_p->data[2] == 1);
memcpy(key_p, next_key_p, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == 0);
assert(next_key_p->prefixlen == 24 && next_key_p->data[0] == 192 &&
next_key_p->data[1] == 168 && next_key_p->data[2] == 128);
memcpy(key_p, next_key_p, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == 0);
assert(next_key_p->prefixlen == 16 && next_key_p->data[0] == 192 &&
next_key_p->data[1] == 168);
memcpy(key_p, next_key_p, key_size);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == -1 &&
errno == ENOENT);
/* no exact matching key should return the first one in post order */
key_p->prefixlen = 22;
inet_pton(AF_INET, "192.168.1.0", key_p->data);
assert(bpf_map_get_next_key(map_fd, key_p, next_key_p) == 0);
assert(next_key_p->prefixlen == 24 && next_key_p->data[0] == 192 &&
next_key_p->data[1] == 168 && next_key_p->data[2] == 0);
close(map_fd);
}
int main(void)
{
struct rlimit limit = { RLIM_INFINITY, RLIM_INFINITY };
......@@ -545,6 +665,8 @@ int main(void)
test_lpm_delete();
test_lpm_get_next_key();
printf("test_lpm: OK\n");
return 0;
}
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