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 *free_node = NULL; 312 struct lpm_trie_node __rcu **slot; 313 struct bpf_lpm_trie_key_u8 *key = _key; 314 unsigned long irq_flags; 315 unsigned int next_bit; 316 size_t matchlen = 0; 317 int ret = 0; 318 319 if (unlikely(flags > BPF_EXIST)) 320 return -EINVAL; 321 322 if (key->prefixlen > trie->max_prefixlen) 323 return -EINVAL; 324 325 spin_lock_irqsave(&trie->lock, irq_flags); 326 327 /* Allocate and fill a new node */ 328 329 if (trie->n_entries == trie->map.max_entries) { 330 ret = -ENOSPC; 331 goto out; 332 } 333 334 new_node = lpm_trie_node_alloc(trie, value); 335 if (!new_node) { 336 ret = -ENOMEM; 337 goto out; 338 } 339 340 trie->n_entries++; 341 342 new_node->prefixlen = key->prefixlen; 343 RCU_INIT_POINTER(new_node->child[0], NULL); 344 RCU_INIT_POINTER(new_node->child[1], NULL); 345 memcpy(new_node->data, key->data, trie->data_size); 346 347 /* Now find a slot to attach the new node. To do that, walk the tree 348 * from the root and match as many bits as possible for each node until 349 * we either find an empty slot or a slot that needs to be replaced by 350 * an intermediate node. 351 */ 352 slot = &trie->root; 353 354 while ((node = rcu_dereference_protected(*slot, 355 lockdep_is_held(&trie->lock)))) { 356 matchlen = longest_prefix_match(trie, node, key); 357 358 if (node->prefixlen != matchlen || 359 node->prefixlen == key->prefixlen || 360 node->prefixlen == trie->max_prefixlen) 361 break; 362 363 next_bit = extract_bit(key->data, node->prefixlen); 364 slot = &node->child[next_bit]; 365 } 366 367 /* If the slot is empty (a free child pointer or an empty root), 368 * simply assign the @new_node to that slot and be done. 369 */ 370 if (!node) { 371 rcu_assign_pointer(*slot, new_node); 372 goto out; 373 } 374 375 /* If the slot we picked already exists, replace it with @new_node 376 * which already has the correct data array set. 377 */ 378 if (node->prefixlen == matchlen) { 379 new_node->child[0] = node->child[0]; 380 new_node->child[1] = node->child[1]; 381 382 if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) 383 trie->n_entries--; 384 385 rcu_assign_pointer(*slot, new_node); 386 free_node = node; 387 388 goto out; 389 } 390 391 /* If the new node matches the prefix completely, it must be inserted 392 * as an ancestor. Simply insert it between @node and *@slot. 393 */ 394 if (matchlen == key->prefixlen) { 395 next_bit = extract_bit(node->data, matchlen); 396 rcu_assign_pointer(new_node->child[next_bit], node); 397 rcu_assign_pointer(*slot, new_node); 398 goto out; 399 } 400 401 im_node = lpm_trie_node_alloc(trie, NULL); 402 if (!im_node) { 403 ret = -ENOMEM; 404 goto out; 405 } 406 407 im_node->prefixlen = matchlen; 408 im_node->flags |= LPM_TREE_NODE_FLAG_IM; 409 memcpy(im_node->data, node->data, trie->data_size); 410 411 /* Now determine which child to install in which slot */ 412 if (extract_bit(key->data, matchlen)) { 413 rcu_assign_pointer(im_node->child[0], node); 414 rcu_assign_pointer(im_node->child[1], new_node); 415 } else { 416 rcu_assign_pointer(im_node->child[0], new_node); 417 rcu_assign_pointer(im_node->child[1], node); 418 } 419 420 /* Finally, assign the intermediate node to the determined slot */ 421 rcu_assign_pointer(*slot, im_node); 422 423 out: 424 if (ret) { 425 if (new_node) 426 trie->n_entries--; 427 428 kfree(new_node); 429 kfree(im_node); 430 } 431 432 spin_unlock_irqrestore(&trie->lock, irq_flags); 433 kfree_rcu(free_node, rcu); 434 435 return ret; 436 } 437 438 /* Called from syscall or from eBPF program */ 439 static long trie_delete_elem(struct bpf_map *map, void *_key) 440 { 441 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 442 struct lpm_trie_node *free_node = NULL, *free_parent = NULL; 443 struct bpf_lpm_trie_key_u8 *key = _key; 444 struct lpm_trie_node __rcu **trim, **trim2; 445 struct lpm_trie_node *node, *parent; 446 unsigned long irq_flags; 447 unsigned int next_bit; 448 size_t matchlen = 0; 449 int ret = 0; 450 451 if (key->prefixlen > trie->max_prefixlen) 452 return -EINVAL; 453 454 spin_lock_irqsave(&trie->lock, irq_flags); 455 456 /* Walk the tree looking for an exact key/length match and keeping 457 * track of the path we traverse. We will need to know the node 458 * we wish to delete, and the slot that points to the node we want 459 * to delete. We may also need to know the nodes parent and the 460 * slot that contains it. 461 */ 462 trim = &trie->root; 463 trim2 = trim; 464 parent = NULL; 465 while ((node = rcu_dereference_protected( 466 *trim, lockdep_is_held(&trie->lock)))) { 467 matchlen = longest_prefix_match(trie, node, key); 468 469 if (node->prefixlen != matchlen || 470 node->prefixlen == key->prefixlen) 471 break; 472 473 parent = node; 474 trim2 = trim; 475 next_bit = extract_bit(key->data, node->prefixlen); 476 trim = &node->child[next_bit]; 477 } 478 479 if (!node || node->prefixlen != key->prefixlen || 480 node->prefixlen != matchlen || 481 (node->flags & LPM_TREE_NODE_FLAG_IM)) { 482 ret = -ENOENT; 483 goto out; 484 } 485 486 trie->n_entries--; 487 488 /* If the node we are removing has two children, simply mark it 489 * as intermediate and we are done. 490 */ 491 if (rcu_access_pointer(node->child[0]) && 492 rcu_access_pointer(node->child[1])) { 493 node->flags |= LPM_TREE_NODE_FLAG_IM; 494 goto out; 495 } 496 497 /* If the parent of the node we are about to delete is an intermediate 498 * node, and the deleted node doesn't have any children, we can delete 499 * the intermediate parent as well and promote its other child 500 * up the tree. Doing this maintains the invariant that all 501 * intermediate nodes have exactly 2 children and that there are no 502 * unnecessary intermediate nodes in the tree. 503 */ 504 if (parent && (parent->flags & LPM_TREE_NODE_FLAG_IM) && 505 !node->child[0] && !node->child[1]) { 506 if (node == rcu_access_pointer(parent->child[0])) 507 rcu_assign_pointer( 508 *trim2, rcu_access_pointer(parent->child[1])); 509 else 510 rcu_assign_pointer( 511 *trim2, rcu_access_pointer(parent->child[0])); 512 free_parent = parent; 513 free_node = node; 514 goto out; 515 } 516 517 /* The node we are removing has either zero or one child. If there 518 * is a child, move it into the removed node's slot then delete 519 * the node. Otherwise just clear the slot and delete the node. 520 */ 521 if (node->child[0]) 522 rcu_assign_pointer(*trim, rcu_access_pointer(node->child[0])); 523 else if (node->child[1]) 524 rcu_assign_pointer(*trim, rcu_access_pointer(node->child[1])); 525 else 526 RCU_INIT_POINTER(*trim, NULL); 527 free_node = node; 528 529 out: 530 spin_unlock_irqrestore(&trie->lock, irq_flags); 531 kfree_rcu(free_parent, rcu); 532 kfree_rcu(free_node, rcu); 533 534 return ret; 535 } 536 537 #define LPM_DATA_SIZE_MAX 256 538 #define LPM_DATA_SIZE_MIN 1 539 540 #define LPM_VAL_SIZE_MAX (KMALLOC_MAX_SIZE - LPM_DATA_SIZE_MAX - \ 541 sizeof(struct lpm_trie_node)) 542 #define LPM_VAL_SIZE_MIN 1 543 544 #define LPM_KEY_SIZE(X) (sizeof(struct bpf_lpm_trie_key_u8) + (X)) 545 #define LPM_KEY_SIZE_MAX LPM_KEY_SIZE(LPM_DATA_SIZE_MAX) 546 #define LPM_KEY_SIZE_MIN LPM_KEY_SIZE(LPM_DATA_SIZE_MIN) 547 548 #define LPM_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_NUMA_NODE | \ 549 BPF_F_ACCESS_MASK) 550 551 static struct bpf_map *trie_alloc(union bpf_attr *attr) 552 { 553 struct lpm_trie *trie; 554 555 /* check sanity of attributes */ 556 if (attr->max_entries == 0 || 557 !(attr->map_flags & BPF_F_NO_PREALLOC) || 558 attr->map_flags & ~LPM_CREATE_FLAG_MASK || 559 !bpf_map_flags_access_ok(attr->map_flags) || 560 attr->key_size < LPM_KEY_SIZE_MIN || 561 attr->key_size > LPM_KEY_SIZE_MAX || 562 attr->value_size < LPM_VAL_SIZE_MIN || 563 attr->value_size > LPM_VAL_SIZE_MAX) 564 return ERR_PTR(-EINVAL); 565 566 trie = bpf_map_area_alloc(sizeof(*trie), NUMA_NO_NODE); 567 if (!trie) 568 return ERR_PTR(-ENOMEM); 569 570 /* copy mandatory map attributes */ 571 bpf_map_init_from_attr(&trie->map, attr); 572 trie->data_size = attr->key_size - 573 offsetof(struct bpf_lpm_trie_key_u8, data); 574 trie->max_prefixlen = trie->data_size * 8; 575 576 spin_lock_init(&trie->lock); 577 578 return &trie->map; 579 } 580 581 static void trie_free(struct bpf_map *map) 582 { 583 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 584 struct lpm_trie_node __rcu **slot; 585 struct lpm_trie_node *node; 586 587 /* Always start at the root and walk down to a node that has no 588 * children. Then free that node, nullify its reference in the parent 589 * and start over. 590 */ 591 592 for (;;) { 593 slot = &trie->root; 594 595 for (;;) { 596 node = rcu_dereference_protected(*slot, 1); 597 if (!node) 598 goto out; 599 600 if (rcu_access_pointer(node->child[0])) { 601 slot = &node->child[0]; 602 continue; 603 } 604 605 if (rcu_access_pointer(node->child[1])) { 606 slot = &node->child[1]; 607 continue; 608 } 609 610 kfree(node); 611 RCU_INIT_POINTER(*slot, NULL); 612 break; 613 } 614 } 615 616 out: 617 bpf_map_area_free(trie); 618 } 619 620 static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key) 621 { 622 struct lpm_trie_node *node, *next_node = NULL, *parent, *search_root; 623 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 624 struct bpf_lpm_trie_key_u8 *key = _key, *next_key = _next_key; 625 struct lpm_trie_node **node_stack = NULL; 626 int err = 0, stack_ptr = -1; 627 unsigned int next_bit; 628 size_t matchlen; 629 630 /* The get_next_key follows postorder. For the 4 node example in 631 * the top of this file, the trie_get_next_key() returns the following 632 * one after another: 633 * 192.168.0.0/24 634 * 192.168.1.0/24 635 * 192.168.128.0/24 636 * 192.168.0.0/16 637 * 638 * The idea is to return more specific keys before less specific ones. 639 */ 640 641 /* Empty trie */ 642 search_root = rcu_dereference(trie->root); 643 if (!search_root) 644 return -ENOENT; 645 646 /* For invalid key, find the leftmost node in the trie */ 647 if (!key || key->prefixlen > trie->max_prefixlen) 648 goto find_leftmost; 649 650 node_stack = kmalloc_array(trie->max_prefixlen, 651 sizeof(struct lpm_trie_node *), 652 GFP_ATOMIC | __GFP_NOWARN); 653 if (!node_stack) 654 return -ENOMEM; 655 656 /* Try to find the exact node for the given key */ 657 for (node = search_root; node;) { 658 node_stack[++stack_ptr] = node; 659 matchlen = longest_prefix_match(trie, node, key); 660 if (node->prefixlen != matchlen || 661 node->prefixlen == key->prefixlen) 662 break; 663 664 next_bit = extract_bit(key->data, node->prefixlen); 665 node = rcu_dereference(node->child[next_bit]); 666 } 667 if (!node || node->prefixlen != key->prefixlen || 668 (node->flags & LPM_TREE_NODE_FLAG_IM)) 669 goto find_leftmost; 670 671 /* The node with the exactly-matching key has been found, 672 * find the first node in postorder after the matched node. 673 */ 674 node = node_stack[stack_ptr]; 675 while (stack_ptr > 0) { 676 parent = node_stack[stack_ptr - 1]; 677 if (rcu_dereference(parent->child[0]) == node) { 678 search_root = rcu_dereference(parent->child[1]); 679 if (search_root) 680 goto find_leftmost; 681 } 682 if (!(parent->flags & LPM_TREE_NODE_FLAG_IM)) { 683 next_node = parent; 684 goto do_copy; 685 } 686 687 node = parent; 688 stack_ptr--; 689 } 690 691 /* did not find anything */ 692 err = -ENOENT; 693 goto free_stack; 694 695 find_leftmost: 696 /* Find the leftmost non-intermediate node, all intermediate nodes 697 * have exact two children, so this function will never return NULL. 698 */ 699 for (node = search_root; node;) { 700 if (node->flags & LPM_TREE_NODE_FLAG_IM) { 701 node = rcu_dereference(node->child[0]); 702 } else { 703 next_node = node; 704 node = rcu_dereference(node->child[0]); 705 if (!node) 706 node = rcu_dereference(next_node->child[1]); 707 } 708 } 709 do_copy: 710 next_key->prefixlen = next_node->prefixlen; 711 memcpy((void *)next_key + offsetof(struct bpf_lpm_trie_key_u8, data), 712 next_node->data, trie->data_size); 713 free_stack: 714 kfree(node_stack); 715 return err; 716 } 717 718 static int trie_check_btf(const struct bpf_map *map, 719 const struct btf *btf, 720 const struct btf_type *key_type, 721 const struct btf_type *value_type) 722 { 723 /* Keys must have struct bpf_lpm_trie_key_u8 embedded. */ 724 return BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ? 725 -EINVAL : 0; 726 } 727 728 static u64 trie_mem_usage(const struct bpf_map *map) 729 { 730 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 731 u64 elem_size; 732 733 elem_size = sizeof(struct lpm_trie_node) + trie->data_size + 734 trie->map.value_size; 735 return elem_size * READ_ONCE(trie->n_entries); 736 } 737 738 BTF_ID_LIST_SINGLE(trie_map_btf_ids, struct, lpm_trie) 739 const struct bpf_map_ops trie_map_ops = { 740 .map_meta_equal = bpf_map_meta_equal, 741 .map_alloc = trie_alloc, 742 .map_free = trie_free, 743 .map_get_next_key = trie_get_next_key, 744 .map_lookup_elem = trie_lookup_elem, 745 .map_update_elem = trie_update_elem, 746 .map_delete_elem = trie_delete_elem, 747 .map_lookup_batch = generic_map_lookup_batch, 748 .map_update_batch = generic_map_update_batch, 749 .map_delete_batch = generic_map_delete_batch, 750 .map_check_btf = trie_check_btf, 751 .map_mem_usage = trie_mem_usage, 752 .map_btf_id = &trie_map_btf_ids[0], 753 }; 754