1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Longest prefix match list implementation 4 * 5 * Copyright (c) 2016,2017 Daniel Mack 6 * Copyright (c) 2016 David Herrmann 7 */ 8 9 #include <linux/bpf.h> 10 #include <linux/btf.h> 11 #include <linux/err.h> 12 #include <linux/slab.h> 13 #include <linux/spinlock.h> 14 #include <linux/vmalloc.h> 15 #include <net/ipv6.h> 16 #include <uapi/linux/btf.h> 17 #include <linux/btf_ids.h> 18 19 /* Intermediate node */ 20 #define LPM_TREE_NODE_FLAG_IM BIT(0) 21 22 struct lpm_trie_node; 23 24 struct lpm_trie_node { 25 struct rcu_head rcu; 26 struct lpm_trie_node __rcu *child[2]; 27 u32 prefixlen; 28 u32 flags; 29 u8 data[]; 30 }; 31 32 struct lpm_trie { 33 struct bpf_map map; 34 struct lpm_trie_node __rcu *root; 35 size_t n_entries; 36 size_t max_prefixlen; 37 size_t data_size; 38 spinlock_t lock; 39 }; 40 41 /* This trie implements a longest prefix match algorithm that can be used to 42 * match IP addresses to a stored set of ranges. 43 * 44 * Data stored in @data of struct bpf_lpm_key and struct lpm_trie_node is 45 * interpreted as big endian, so data[0] stores the most significant byte. 46 * 47 * Match ranges are internally stored in instances of struct lpm_trie_node 48 * which each contain their prefix length as well as two pointers that may 49 * lead to more nodes containing more specific matches. Each node also stores 50 * a value that is defined by and returned to userspace via the update_elem 51 * and lookup functions. 52 * 53 * For instance, let's start with a trie that was created with a prefix length 54 * of 32, so it can be used for IPv4 addresses, and one single element that 55 * matches 192.168.0.0/16. The data array would hence contain 56 * [0xc0, 0xa8, 0x00, 0x00] in big-endian notation. This documentation will 57 * stick to IP-address notation for readability though. 58 * 59 * As the trie is empty initially, the new node (1) will be places as root 60 * node, denoted as (R) in the example below. As there are no other node, both 61 * child pointers are %NULL. 62 * 63 * +----------------+ 64 * | (1) (R) | 65 * | 192.168.0.0/16 | 66 * | value: 1 | 67 * | [0] [1] | 68 * +----------------+ 69 * 70 * Next, let's add a new node (2) matching 192.168.0.0/24. As there is already 71 * a node with the same data and a smaller prefix (ie, a less specific one), 72 * node (2) will become a child of (1). In child index depends on the next bit 73 * that is outside of what (1) matches, and that bit is 0, so (2) will be 74 * child[0] of (1): 75 * 76 * +----------------+ 77 * | (1) (R) | 78 * | 192.168.0.0/16 | 79 * | value: 1 | 80 * | [0] [1] | 81 * +----------------+ 82 * | 83 * +----------------+ 84 * | (2) | 85 * | 192.168.0.0/24 | 86 * | value: 2 | 87 * | [0] [1] | 88 * +----------------+ 89 * 90 * The child[1] slot of (1) could be filled with another node which has bit #17 91 * (the next bit after the ones that (1) matches on) set to 1. For instance, 92 * 192.168.128.0/24: 93 * 94 * +----------------+ 95 * | (1) (R) | 96 * | 192.168.0.0/16 | 97 * | value: 1 | 98 * | [0] [1] | 99 * +----------------+ 100 * | | 101 * +----------------+ +------------------+ 102 * | (2) | | (3) | 103 * | 192.168.0.0/24 | | 192.168.128.0/24 | 104 * | value: 2 | | value: 3 | 105 * | [0] [1] | | [0] [1] | 106 * +----------------+ +------------------+ 107 * 108 * Let's add another node (4) to the game for 192.168.1.0/24. In order to place 109 * it, node (1) is looked at first, and because (4) of the semantics laid out 110 * above (bit #17 is 0), it would normally be attached to (1) as child[0]. 111 * However, that slot is already allocated, so a new node is needed in between. 112 * That node does not have a value attached to it and it will never be 113 * returned to users as result of a lookup. It is only there to differentiate 114 * the traversal further. It will get a prefix as wide as necessary to 115 * distinguish its two children: 116 * 117 * +----------------+ 118 * | (1) (R) | 119 * | 192.168.0.0/16 | 120 * | value: 1 | 121 * | [0] [1] | 122 * +----------------+ 123 * | | 124 * +----------------+ +------------------+ 125 * | (4) (I) | | (3) | 126 * | 192.168.0.0/23 | | 192.168.128.0/24 | 127 * | value: --- | | value: 3 | 128 * | [0] [1] | | [0] [1] | 129 * +----------------+ +------------------+ 130 * | | 131 * +----------------+ +----------------+ 132 * | (2) | | (5) | 133 * | 192.168.0.0/24 | | 192.168.1.0/24 | 134 * | value: 2 | | value: 5 | 135 * | [0] [1] | | [0] [1] | 136 * +----------------+ +----------------+ 137 * 138 * 192.168.1.1/32 would be a child of (5) etc. 139 * 140 * An intermediate node will be turned into a 'real' node on demand. In the 141 * example above, (4) would be re-used if 192.168.0.0/23 is added to the trie. 142 * 143 * A fully populated trie would have a height of 32 nodes, as the trie was 144 * created with a prefix length of 32. 145 * 146 * The lookup starts at the root node. If the current node matches and if there 147 * is a child that can be used to become more specific, the trie is traversed 148 * downwards. The last node in the traversal that is a non-intermediate one is 149 * returned. 150 */ 151 152 static inline int extract_bit(const u8 *data, size_t index) 153 { 154 return !!(data[index / 8] & (1 << (7 - (index % 8)))); 155 } 156 157 /** 158 * longest_prefix_match() - determine the longest prefix 159 * @trie: The trie to get internal sizes from 160 * @node: The node to operate on 161 * @key: The key to compare to @node 162 * 163 * Determine the longest prefix of @node that matches the bits in @key. 164 */ 165 static size_t longest_prefix_match(const struct lpm_trie *trie, 166 const struct lpm_trie_node *node, 167 const struct bpf_lpm_trie_key_u8 *key) 168 { 169 u32 limit = min(node->prefixlen, key->prefixlen); 170 u32 prefixlen = 0, i = 0; 171 172 BUILD_BUG_ON(offsetof(struct lpm_trie_node, data) % sizeof(u32)); 173 BUILD_BUG_ON(offsetof(struct bpf_lpm_trie_key_u8, data) % sizeof(u32)); 174 175 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(CONFIG_64BIT) 176 177 /* data_size >= 16 has very small probability. 178 * We do not use a loop for optimal code generation. 179 */ 180 if (trie->data_size >= 8) { 181 u64 diff = be64_to_cpu(*(__be64 *)node->data ^ 182 *(__be64 *)key->data); 183 184 prefixlen = 64 - fls64(diff); 185 if (prefixlen >= limit) 186 return limit; 187 if (diff) 188 return prefixlen; 189 i = 8; 190 } 191 #endif 192 193 while (trie->data_size >= i + 4) { 194 u32 diff = be32_to_cpu(*(__be32 *)&node->data[i] ^ 195 *(__be32 *)&key->data[i]); 196 197 prefixlen += 32 - fls(diff); 198 if (prefixlen >= limit) 199 return limit; 200 if (diff) 201 return prefixlen; 202 i += 4; 203 } 204 205 if (trie->data_size >= i + 2) { 206 u16 diff = be16_to_cpu(*(__be16 *)&node->data[i] ^ 207 *(__be16 *)&key->data[i]); 208 209 prefixlen += 16 - fls(diff); 210 if (prefixlen >= limit) 211 return limit; 212 if (diff) 213 return prefixlen; 214 i += 2; 215 } 216 217 if (trie->data_size >= i + 1) { 218 prefixlen += 8 - fls(node->data[i] ^ key->data[i]); 219 220 if (prefixlen >= limit) 221 return limit; 222 } 223 224 return prefixlen; 225 } 226 227 /* Called from syscall or from eBPF program */ 228 static void *trie_lookup_elem(struct bpf_map *map, void *_key) 229 { 230 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 231 struct lpm_trie_node *node, *found = NULL; 232 struct bpf_lpm_trie_key_u8 *key = _key; 233 234 if (key->prefixlen > trie->max_prefixlen) 235 return NULL; 236 237 /* Start walking the trie from the root node ... */ 238 239 for (node = rcu_dereference_check(trie->root, rcu_read_lock_bh_held()); 240 node;) { 241 unsigned int next_bit; 242 size_t matchlen; 243 244 /* Determine the longest prefix of @node that matches @key. 245 * If it's the maximum possible prefix for this trie, we have 246 * an exact match and can return it directly. 247 */ 248 matchlen = longest_prefix_match(trie, node, key); 249 if (matchlen == trie->max_prefixlen) { 250 found = node; 251 break; 252 } 253 254 /* If the number of bits that match is smaller than the prefix 255 * length of @node, bail out and return the node we have seen 256 * last in the traversal (ie, the parent). 257 */ 258 if (matchlen < node->prefixlen) 259 break; 260 261 /* Consider this node as return candidate unless it is an 262 * artificially added intermediate one. 263 */ 264 if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) 265 found = node; 266 267 /* If the node match is fully satisfied, let's see if we can 268 * become more specific. Determine the next bit in the key and 269 * traverse down. 270 */ 271 next_bit = extract_bit(key->data, node->prefixlen); 272 node = rcu_dereference_check(node->child[next_bit], 273 rcu_read_lock_bh_held()); 274 } 275 276 if (!found) 277 return NULL; 278 279 return found->data + trie->data_size; 280 } 281 282 static struct lpm_trie_node *lpm_trie_node_alloc(const struct lpm_trie *trie, 283 const void *value) 284 { 285 struct lpm_trie_node *node; 286 size_t size = sizeof(struct lpm_trie_node) + trie->data_size; 287 288 if (value) 289 size += trie->map.value_size; 290 291 node = bpf_map_kmalloc_node(&trie->map, size, GFP_NOWAIT | __GFP_NOWARN, 292 trie->map.numa_node); 293 if (!node) 294 return NULL; 295 296 node->flags = 0; 297 298 if (value) 299 memcpy(node->data + trie->data_size, value, 300 trie->map.value_size); 301 302 return node; 303 } 304 305 /* Called from syscall or from eBPF program */ 306 static long trie_update_elem(struct bpf_map *map, 307 void *_key, void *value, u64 flags) 308 { 309 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 310 struct lpm_trie_node *node, *im_node = NULL, *new_node = NULL; 311 struct lpm_trie_node __rcu **slot; 312 struct bpf_lpm_trie_key_u8 *key = _key; 313 unsigned long irq_flags; 314 unsigned int next_bit; 315 size_t matchlen = 0; 316 int ret = 0; 317 318 if (unlikely(flags > BPF_EXIST)) 319 return -EINVAL; 320 321 if (key->prefixlen > trie->max_prefixlen) 322 return -EINVAL; 323 324 spin_lock_irqsave(&trie->lock, irq_flags); 325 326 /* Allocate and fill a new node */ 327 328 if (trie->n_entries == trie->map.max_entries) { 329 ret = -ENOSPC; 330 goto out; 331 } 332 333 new_node = lpm_trie_node_alloc(trie, value); 334 if (!new_node) { 335 ret = -ENOMEM; 336 goto out; 337 } 338 339 trie->n_entries++; 340 341 new_node->prefixlen = key->prefixlen; 342 RCU_INIT_POINTER(new_node->child[0], NULL); 343 RCU_INIT_POINTER(new_node->child[1], NULL); 344 memcpy(new_node->data, key->data, trie->data_size); 345 346 /* Now find a slot to attach the new node. To do that, walk the tree 347 * from the root and match as many bits as possible for each node until 348 * we either find an empty slot or a slot that needs to be replaced by 349 * an intermediate node. 350 */ 351 slot = &trie->root; 352 353 while ((node = rcu_dereference_protected(*slot, 354 lockdep_is_held(&trie->lock)))) { 355 matchlen = longest_prefix_match(trie, node, key); 356 357 if (node->prefixlen != matchlen || 358 node->prefixlen == key->prefixlen || 359 node->prefixlen == trie->max_prefixlen) 360 break; 361 362 next_bit = extract_bit(key->data, node->prefixlen); 363 slot = &node->child[next_bit]; 364 } 365 366 /* If the slot is empty (a free child pointer or an empty root), 367 * simply assign the @new_node to that slot and be done. 368 */ 369 if (!node) { 370 rcu_assign_pointer(*slot, new_node); 371 goto out; 372 } 373 374 /* If the slot we picked already exists, replace it with @new_node 375 * which already has the correct data array set. 376 */ 377 if (node->prefixlen == matchlen) { 378 new_node->child[0] = node->child[0]; 379 new_node->child[1] = node->child[1]; 380 381 if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) 382 trie->n_entries--; 383 384 rcu_assign_pointer(*slot, new_node); 385 kfree_rcu(node, rcu); 386 387 goto out; 388 } 389 390 /* If the new node matches the prefix completely, it must be inserted 391 * as an ancestor. Simply insert it between @node and *@slot. 392 */ 393 if (matchlen == key->prefixlen) { 394 next_bit = extract_bit(node->data, matchlen); 395 rcu_assign_pointer(new_node->child[next_bit], node); 396 rcu_assign_pointer(*slot, new_node); 397 goto out; 398 } 399 400 im_node = lpm_trie_node_alloc(trie, NULL); 401 if (!im_node) { 402 ret = -ENOMEM; 403 goto out; 404 } 405 406 im_node->prefixlen = matchlen; 407 im_node->flags |= LPM_TREE_NODE_FLAG_IM; 408 memcpy(im_node->data, node->data, trie->data_size); 409 410 /* Now determine which child to install in which slot */ 411 if (extract_bit(key->data, matchlen)) { 412 rcu_assign_pointer(im_node->child[0], node); 413 rcu_assign_pointer(im_node->child[1], new_node); 414 } else { 415 rcu_assign_pointer(im_node->child[0], new_node); 416 rcu_assign_pointer(im_node->child[1], node); 417 } 418 419 /* Finally, assign the intermediate node to the determined slot */ 420 rcu_assign_pointer(*slot, im_node); 421 422 out: 423 if (ret) { 424 if (new_node) 425 trie->n_entries--; 426 427 kfree(new_node); 428 kfree(im_node); 429 } 430 431 spin_unlock_irqrestore(&trie->lock, irq_flags); 432 433 return ret; 434 } 435 436 /* Called from syscall or from eBPF program */ 437 static long trie_delete_elem(struct bpf_map *map, void *_key) 438 { 439 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 440 struct bpf_lpm_trie_key_u8 *key = _key; 441 struct lpm_trie_node __rcu **trim, **trim2; 442 struct lpm_trie_node *node, *parent; 443 unsigned long irq_flags; 444 unsigned int next_bit; 445 size_t matchlen = 0; 446 int ret = 0; 447 448 if (key->prefixlen > trie->max_prefixlen) 449 return -EINVAL; 450 451 spin_lock_irqsave(&trie->lock, irq_flags); 452 453 /* Walk the tree looking for an exact key/length match and keeping 454 * track of the path we traverse. We will need to know the node 455 * we wish to delete, and the slot that points to the node we want 456 * to delete. We may also need to know the nodes parent and the 457 * slot that contains it. 458 */ 459 trim = &trie->root; 460 trim2 = trim; 461 parent = NULL; 462 while ((node = rcu_dereference_protected( 463 *trim, lockdep_is_held(&trie->lock)))) { 464 matchlen = longest_prefix_match(trie, node, key); 465 466 if (node->prefixlen != matchlen || 467 node->prefixlen == key->prefixlen) 468 break; 469 470 parent = node; 471 trim2 = trim; 472 next_bit = extract_bit(key->data, node->prefixlen); 473 trim = &node->child[next_bit]; 474 } 475 476 if (!node || node->prefixlen != key->prefixlen || 477 node->prefixlen != matchlen || 478 (node->flags & LPM_TREE_NODE_FLAG_IM)) { 479 ret = -ENOENT; 480 goto out; 481 } 482 483 trie->n_entries--; 484 485 /* If the node we are removing has two children, simply mark it 486 * as intermediate and we are done. 487 */ 488 if (rcu_access_pointer(node->child[0]) && 489 rcu_access_pointer(node->child[1])) { 490 node->flags |= LPM_TREE_NODE_FLAG_IM; 491 goto out; 492 } 493 494 /* If the parent of the node we are about to delete is an intermediate 495 * node, and the deleted node doesn't have any children, we can delete 496 * the intermediate parent as well and promote its other child 497 * up the tree. Doing this maintains the invariant that all 498 * intermediate nodes have exactly 2 children and that there are no 499 * unnecessary intermediate nodes in the tree. 500 */ 501 if (parent && (parent->flags & LPM_TREE_NODE_FLAG_IM) && 502 !node->child[0] && !node->child[1]) { 503 if (node == rcu_access_pointer(parent->child[0])) 504 rcu_assign_pointer( 505 *trim2, rcu_access_pointer(parent->child[1])); 506 else 507 rcu_assign_pointer( 508 *trim2, rcu_access_pointer(parent->child[0])); 509 kfree_rcu(parent, rcu); 510 kfree_rcu(node, rcu); 511 goto out; 512 } 513 514 /* The node we are removing has either zero or one child. If there 515 * is a child, move it into the removed node's slot then delete 516 * the node. Otherwise just clear the slot and delete the node. 517 */ 518 if (node->child[0]) 519 rcu_assign_pointer(*trim, rcu_access_pointer(node->child[0])); 520 else if (node->child[1]) 521 rcu_assign_pointer(*trim, rcu_access_pointer(node->child[1])); 522 else 523 RCU_INIT_POINTER(*trim, NULL); 524 kfree_rcu(node, rcu); 525 526 out: 527 spin_unlock_irqrestore(&trie->lock, irq_flags); 528 529 return ret; 530 } 531 532 #define LPM_DATA_SIZE_MAX 256 533 #define LPM_DATA_SIZE_MIN 1 534 535 #define LPM_VAL_SIZE_MAX (KMALLOC_MAX_SIZE - LPM_DATA_SIZE_MAX - \ 536 sizeof(struct lpm_trie_node)) 537 #define LPM_VAL_SIZE_MIN 1 538 539 #define LPM_KEY_SIZE(X) (sizeof(struct bpf_lpm_trie_key_u8) + (X)) 540 #define LPM_KEY_SIZE_MAX LPM_KEY_SIZE(LPM_DATA_SIZE_MAX) 541 #define LPM_KEY_SIZE_MIN LPM_KEY_SIZE(LPM_DATA_SIZE_MIN) 542 543 #define LPM_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_NUMA_NODE | \ 544 BPF_F_ACCESS_MASK) 545 546 static struct bpf_map *trie_alloc(union bpf_attr *attr) 547 { 548 struct lpm_trie *trie; 549 550 /* check sanity of attributes */ 551 if (attr->max_entries == 0 || 552 !(attr->map_flags & BPF_F_NO_PREALLOC) || 553 attr->map_flags & ~LPM_CREATE_FLAG_MASK || 554 !bpf_map_flags_access_ok(attr->map_flags) || 555 attr->key_size < LPM_KEY_SIZE_MIN || 556 attr->key_size > LPM_KEY_SIZE_MAX || 557 attr->value_size < LPM_VAL_SIZE_MIN || 558 attr->value_size > LPM_VAL_SIZE_MAX) 559 return ERR_PTR(-EINVAL); 560 561 trie = bpf_map_area_alloc(sizeof(*trie), NUMA_NO_NODE); 562 if (!trie) 563 return ERR_PTR(-ENOMEM); 564 565 /* copy mandatory map attributes */ 566 bpf_map_init_from_attr(&trie->map, attr); 567 trie->data_size = attr->key_size - 568 offsetof(struct bpf_lpm_trie_key_u8, data); 569 trie->max_prefixlen = trie->data_size * 8; 570 571 spin_lock_init(&trie->lock); 572 573 return &trie->map; 574 } 575 576 static void trie_free(struct bpf_map *map) 577 { 578 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 579 struct lpm_trie_node __rcu **slot; 580 struct lpm_trie_node *node; 581 582 /* Always start at the root and walk down to a node that has no 583 * children. Then free that node, nullify its reference in the parent 584 * and start over. 585 */ 586 587 for (;;) { 588 slot = &trie->root; 589 590 for (;;) { 591 node = rcu_dereference_protected(*slot, 1); 592 if (!node) 593 goto out; 594 595 if (rcu_access_pointer(node->child[0])) { 596 slot = &node->child[0]; 597 continue; 598 } 599 600 if (rcu_access_pointer(node->child[1])) { 601 slot = &node->child[1]; 602 continue; 603 } 604 605 kfree(node); 606 RCU_INIT_POINTER(*slot, NULL); 607 break; 608 } 609 } 610 611 out: 612 bpf_map_area_free(trie); 613 } 614 615 static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key) 616 { 617 struct lpm_trie_node *node, *next_node = NULL, *parent, *search_root; 618 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 619 struct bpf_lpm_trie_key_u8 *key = _key, *next_key = _next_key; 620 struct lpm_trie_node **node_stack = NULL; 621 int err = 0, stack_ptr = -1; 622 unsigned int next_bit; 623 size_t matchlen; 624 625 /* The get_next_key follows postorder. For the 4 node example in 626 * the top of this file, the trie_get_next_key() returns the following 627 * one after another: 628 * 192.168.0.0/24 629 * 192.168.1.0/24 630 * 192.168.128.0/24 631 * 192.168.0.0/16 632 * 633 * The idea is to return more specific keys before less specific ones. 634 */ 635 636 /* Empty trie */ 637 search_root = rcu_dereference(trie->root); 638 if (!search_root) 639 return -ENOENT; 640 641 /* For invalid key, find the leftmost node in the trie */ 642 if (!key || key->prefixlen > trie->max_prefixlen) 643 goto find_leftmost; 644 645 node_stack = kmalloc_array(trie->max_prefixlen, 646 sizeof(struct lpm_trie_node *), 647 GFP_ATOMIC | __GFP_NOWARN); 648 if (!node_stack) 649 return -ENOMEM; 650 651 /* Try to find the exact node for the given key */ 652 for (node = search_root; node;) { 653 node_stack[++stack_ptr] = node; 654 matchlen = longest_prefix_match(trie, node, key); 655 if (node->prefixlen != matchlen || 656 node->prefixlen == key->prefixlen) 657 break; 658 659 next_bit = extract_bit(key->data, node->prefixlen); 660 node = rcu_dereference(node->child[next_bit]); 661 } 662 if (!node || node->prefixlen != key->prefixlen || 663 (node->flags & LPM_TREE_NODE_FLAG_IM)) 664 goto find_leftmost; 665 666 /* The node with the exactly-matching key has been found, 667 * find the first node in postorder after the matched node. 668 */ 669 node = node_stack[stack_ptr]; 670 while (stack_ptr > 0) { 671 parent = node_stack[stack_ptr - 1]; 672 if (rcu_dereference(parent->child[0]) == node) { 673 search_root = rcu_dereference(parent->child[1]); 674 if (search_root) 675 goto find_leftmost; 676 } 677 if (!(parent->flags & LPM_TREE_NODE_FLAG_IM)) { 678 next_node = parent; 679 goto do_copy; 680 } 681 682 node = parent; 683 stack_ptr--; 684 } 685 686 /* did not find anything */ 687 err = -ENOENT; 688 goto free_stack; 689 690 find_leftmost: 691 /* Find the leftmost non-intermediate node, all intermediate nodes 692 * have exact two children, so this function will never return NULL. 693 */ 694 for (node = search_root; node;) { 695 if (node->flags & LPM_TREE_NODE_FLAG_IM) { 696 node = rcu_dereference(node->child[0]); 697 } else { 698 next_node = node; 699 node = rcu_dereference(node->child[0]); 700 if (!node) 701 node = rcu_dereference(next_node->child[1]); 702 } 703 } 704 do_copy: 705 next_key->prefixlen = next_node->prefixlen; 706 memcpy((void *)next_key + offsetof(struct bpf_lpm_trie_key_u8, data), 707 next_node->data, trie->data_size); 708 free_stack: 709 kfree(node_stack); 710 return err; 711 } 712 713 static int trie_check_btf(const struct bpf_map *map, 714 const struct btf *btf, 715 const struct btf_type *key_type, 716 const struct btf_type *value_type) 717 { 718 /* Keys must have struct bpf_lpm_trie_key_u8 embedded. */ 719 return BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ? 720 -EINVAL : 0; 721 } 722 723 static u64 trie_mem_usage(const struct bpf_map *map) 724 { 725 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 726 u64 elem_size; 727 728 elem_size = sizeof(struct lpm_trie_node) + trie->data_size + 729 trie->map.value_size; 730 return elem_size * READ_ONCE(trie->n_entries); 731 } 732 733 BTF_ID_LIST_SINGLE(trie_map_btf_ids, struct, lpm_trie) 734 const struct bpf_map_ops trie_map_ops = { 735 .map_meta_equal = bpf_map_meta_equal, 736 .map_alloc = trie_alloc, 737 .map_free = trie_free, 738 .map_get_next_key = trie_get_next_key, 739 .map_lookup_elem = trie_lookup_elem, 740 .map_update_elem = trie_update_elem, 741 .map_delete_elem = trie_delete_elem, 742 .map_lookup_batch = generic_map_lookup_batch, 743 .map_update_batch = generic_map_update_batch, 744 .map_delete_batch = generic_map_delete_batch, 745 .map_check_btf = trie_check_btf, 746 .map_mem_usage = trie_mem_usage, 747 .map_btf_id = &trie_map_btf_ids[0], 748 }; 749