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 22struct lpm_trie_node; 23 24struct 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 32struct 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 152static 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 */ 165static __always_inline 166size_t __longest_prefix_match(const struct lpm_trie *trie, 167 const struct lpm_trie_node *node, 168 const struct bpf_lpm_trie_key_u8 *key) 169{ 170 u32 limit = min(node->prefixlen, key->prefixlen); 171 u32 prefixlen = 0, i = 0; 172 173 BUILD_BUG_ON(offsetof(struct lpm_trie_node, data) % sizeof(u32)); 174 BUILD_BUG_ON(offsetof(struct bpf_lpm_trie_key_u8, data) % sizeof(u32)); 175 176#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(CONFIG_64BIT) 177 178 /* data_size >= 16 has very small probability. 179 * We do not use a loop for optimal code generation. 180 */ 181 if (trie->data_size >= 8) { 182 u64 diff = be64_to_cpu(*(__be64 *)node->data ^ 183 *(__be64 *)key->data); 184 185 prefixlen = 64 - fls64(diff); 186 if (prefixlen >= limit) 187 return limit; 188 if (diff) 189 return prefixlen; 190 i = 8; 191 } 192#endif 193 194 while (trie->data_size >= i + 4) { 195 u32 diff = be32_to_cpu(*(__be32 *)&node->data[i] ^ 196 *(__be32 *)&key->data[i]); 197 198 prefixlen += 32 - fls(diff); 199 if (prefixlen >= limit) 200 return limit; 201 if (diff) 202 return prefixlen; 203 i += 4; 204 } 205 206 if (trie->data_size >= i + 2) { 207 u16 diff = be16_to_cpu(*(__be16 *)&node->data[i] ^ 208 *(__be16 *)&key->data[i]); 209 210 prefixlen += 16 - fls(diff); 211 if (prefixlen >= limit) 212 return limit; 213 if (diff) 214 return prefixlen; 215 i += 2; 216 } 217 218 if (trie->data_size >= i + 1) { 219 prefixlen += 8 - fls(node->data[i] ^ key->data[i]); 220 221 if (prefixlen >= limit) 222 return limit; 223 } 224 225 return prefixlen; 226} 227 228static size_t longest_prefix_match(const struct lpm_trie *trie, 229 const struct lpm_trie_node *node, 230 const struct bpf_lpm_trie_key_u8 *key) 231{ 232 return __longest_prefix_match(trie, node, key); 233} 234 235/* Called from syscall or from eBPF program */ 236static void *trie_lookup_elem(struct bpf_map *map, void *_key) 237{ 238 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 239 struct lpm_trie_node *node, *found = NULL; 240 struct bpf_lpm_trie_key_u8 *key = _key; 241 242 if (key->prefixlen > trie->max_prefixlen) 243 return NULL; 244 245 /* Start walking the trie from the root node ... */ 246 247 for (node = rcu_dereference_check(trie->root, rcu_read_lock_bh_held()); 248 node;) { 249 unsigned int next_bit; 250 size_t matchlen; 251 252 /* Determine the longest prefix of @node that matches @key. 253 * If it's the maximum possible prefix for this trie, we have 254 * an exact match and can return it directly. 255 */ 256 matchlen = __longest_prefix_match(trie, node, key); 257 if (matchlen == trie->max_prefixlen) { 258 found = node; 259 break; 260 } 261 262 /* If the number of bits that match is smaller than the prefix 263 * length of @node, bail out and return the node we have seen 264 * last in the traversal (ie, the parent). 265 */ 266 if (matchlen < node->prefixlen) 267 break; 268 269 /* Consider this node as return candidate unless it is an 270 * artificially added intermediate one. 271 */ 272 if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) 273 found = node; 274 275 /* If the node match is fully satisfied, let's see if we can 276 * become more specific. Determine the next bit in the key and 277 * traverse down. 278 */ 279 next_bit = extract_bit(key->data, node->prefixlen); 280 node = rcu_dereference_check(node->child[next_bit], 281 rcu_read_lock_bh_held()); 282 } 283 284 if (!found) 285 return NULL; 286 287 return found->data + trie->data_size; 288} 289 290static struct lpm_trie_node *lpm_trie_node_alloc(const struct lpm_trie *trie, 291 const void *value) 292{ 293 struct lpm_trie_node *node; 294 size_t size = sizeof(struct lpm_trie_node) + trie->data_size; 295 296 if (value) 297 size += trie->map.value_size; 298 299 node = bpf_map_kmalloc_node(&trie->map, size, GFP_NOWAIT | __GFP_NOWARN, 300 trie->map.numa_node); 301 if (!node) 302 return NULL; 303 304 node->flags = 0; 305 306 if (value) 307 memcpy(node->data + trie->data_size, value, 308 trie->map.value_size); 309 310 return node; 311} 312 313/* Called from syscall or from eBPF program */ 314static long trie_update_elem(struct bpf_map *map, 315 void *_key, void *value, u64 flags) 316{ 317 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 318 struct lpm_trie_node *node, *im_node = NULL, *new_node = NULL; 319 struct lpm_trie_node *free_node = NULL; 320 struct lpm_trie_node __rcu **slot; 321 struct bpf_lpm_trie_key_u8 *key = _key; 322 unsigned long irq_flags; 323 unsigned int next_bit; 324 size_t matchlen = 0; 325 int ret = 0; 326 327 if (unlikely(flags > BPF_EXIST)) 328 return -EINVAL; 329 330 if (key->prefixlen > trie->max_prefixlen) 331 return -EINVAL; 332 333 spin_lock_irqsave(&trie->lock, irq_flags); 334 335 /* Allocate and fill a new node */ 336 337 if (trie->n_entries == trie->map.max_entries) { 338 ret = -ENOSPC; 339 goto out; 340 } 341 342 new_node = lpm_trie_node_alloc(trie, value); 343 if (!new_node) { 344 ret = -ENOMEM; 345 goto out; 346 } 347 348 trie->n_entries++; 349 350 new_node->prefixlen = key->prefixlen; 351 RCU_INIT_POINTER(new_node->child[0], NULL); 352 RCU_INIT_POINTER(new_node->child[1], NULL); 353 memcpy(new_node->data, key->data, trie->data_size); 354 355 /* Now find a slot to attach the new node. To do that, walk the tree 356 * from the root and match as many bits as possible for each node until 357 * we either find an empty slot or a slot that needs to be replaced by 358 * an intermediate node. 359 */ 360 slot = &trie->root; 361 362 while ((node = rcu_dereference_protected(*slot, 363 lockdep_is_held(&trie->lock)))) { 364 matchlen = longest_prefix_match(trie, node, key); 365 366 if (node->prefixlen != matchlen || 367 node->prefixlen == key->prefixlen || 368 node->prefixlen == trie->max_prefixlen) 369 break; 370 371 next_bit = extract_bit(key->data, node->prefixlen); 372 slot = &node->child[next_bit]; 373 } 374 375 /* If the slot is empty (a free child pointer or an empty root), 376 * simply assign the @new_node to that slot and be done. 377 */ 378 if (!node) { 379 rcu_assign_pointer(*slot, new_node); 380 goto out; 381 } 382 383 /* If the slot we picked already exists, replace it with @new_node 384 * which already has the correct data array set. 385 */ 386 if (node->prefixlen == matchlen) { 387 new_node->child[0] = node->child[0]; 388 new_node->child[1] = node->child[1]; 389 390 if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) 391 trie->n_entries--; 392 393 rcu_assign_pointer(*slot, new_node); 394 free_node = node; 395 396 goto out; 397 } 398 399 /* If the new node matches the prefix completely, it must be inserted 400 * as an ancestor. Simply insert it between @node and *@slot. 401 */ 402 if (matchlen == key->prefixlen) { 403 next_bit = extract_bit(node->data, matchlen); 404 rcu_assign_pointer(new_node->child[next_bit], node); 405 rcu_assign_pointer(*slot, new_node); 406 goto out; 407 } 408 409 im_node = lpm_trie_node_alloc(trie, NULL); 410 if (!im_node) { 411 ret = -ENOMEM; 412 goto out; 413 } 414 415 im_node->prefixlen = matchlen; 416 im_node->flags |= LPM_TREE_NODE_FLAG_IM; 417 memcpy(im_node->data, node->data, trie->data_size); 418 419 /* Now determine which child to install in which slot */ 420 if (extract_bit(key->data, matchlen)) { 421 rcu_assign_pointer(im_node->child[0], node); 422 rcu_assign_pointer(im_node->child[1], new_node); 423 } else { 424 rcu_assign_pointer(im_node->child[0], new_node); 425 rcu_assign_pointer(im_node->child[1], node); 426 } 427 428 /* Finally, assign the intermediate node to the determined slot */ 429 rcu_assign_pointer(*slot, im_node); 430 431out: 432 if (ret) { 433 if (new_node) 434 trie->n_entries--; 435 436 kfree(new_node); 437 kfree(im_node); 438 } 439 440 spin_unlock_irqrestore(&trie->lock, irq_flags); 441 kfree_rcu(free_node, rcu); 442 443 return ret; 444} 445 446/* Called from syscall or from eBPF program */ 447static long trie_delete_elem(struct bpf_map *map, void *_key) 448{ 449 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 450 struct lpm_trie_node *free_node = NULL, *free_parent = NULL; 451 struct bpf_lpm_trie_key_u8 *key = _key; 452 struct lpm_trie_node __rcu **trim, **trim2; 453 struct lpm_trie_node *node, *parent; 454 unsigned long irq_flags; 455 unsigned int next_bit; 456 size_t matchlen = 0; 457 int ret = 0; 458 459 if (key->prefixlen > trie->max_prefixlen) 460 return -EINVAL; 461 462 spin_lock_irqsave(&trie->lock, irq_flags); 463 464 /* Walk the tree looking for an exact key/length match and keeping 465 * track of the path we traverse. We will need to know the node 466 * we wish to delete, and the slot that points to the node we want 467 * to delete. We may also need to know the nodes parent and the 468 * slot that contains it. 469 */ 470 trim = &trie->root; 471 trim2 = trim; 472 parent = NULL; 473 while ((node = rcu_dereference_protected( 474 *trim, lockdep_is_held(&trie->lock)))) { 475 matchlen = longest_prefix_match(trie, node, key); 476 477 if (node->prefixlen != matchlen || 478 node->prefixlen == key->prefixlen) 479 break; 480 481 parent = node; 482 trim2 = trim; 483 next_bit = extract_bit(key->data, node->prefixlen); 484 trim = &node->child[next_bit]; 485 } 486 487 if (!node || node->prefixlen != key->prefixlen || 488 node->prefixlen != matchlen || 489 (node->flags & LPM_TREE_NODE_FLAG_IM)) { 490 ret = -ENOENT; 491 goto out; 492 } 493 494 trie->n_entries--; 495 496 /* If the node we are removing has two children, simply mark it 497 * as intermediate and we are done. 498 */ 499 if (rcu_access_pointer(node->child[0]) && 500 rcu_access_pointer(node->child[1])) { 501 node->flags |= LPM_TREE_NODE_FLAG_IM; 502 goto out; 503 } 504 505 /* If the parent of the node we are about to delete is an intermediate 506 * node, and the deleted node doesn't have any children, we can delete 507 * the intermediate parent as well and promote its other child 508 * up the tree. Doing this maintains the invariant that all 509 * intermediate nodes have exactly 2 children and that there are no 510 * unnecessary intermediate nodes in the tree. 511 */ 512 if (parent && (parent->flags & LPM_TREE_NODE_FLAG_IM) && 513 !node->child[0] && !node->child[1]) { 514 if (node == rcu_access_pointer(parent->child[0])) 515 rcu_assign_pointer( 516 *trim2, rcu_access_pointer(parent->child[1])); 517 else 518 rcu_assign_pointer( 519 *trim2, rcu_access_pointer(parent->child[0])); 520 free_parent = parent; 521 free_node = node; 522 goto out; 523 } 524 525 /* The node we are removing has either zero or one child. If there 526 * is a child, move it into the removed node's slot then delete 527 * the node. Otherwise just clear the slot and delete the node. 528 */ 529 if (node->child[0]) 530 rcu_assign_pointer(*trim, rcu_access_pointer(node->child[0])); 531 else if (node->child[1]) 532 rcu_assign_pointer(*trim, rcu_access_pointer(node->child[1])); 533 else 534 RCU_INIT_POINTER(*trim, NULL); 535 free_node = node; 536 537out: 538 spin_unlock_irqrestore(&trie->lock, irq_flags); 539 kfree_rcu(free_parent, rcu); 540 kfree_rcu(free_node, rcu); 541 542 return ret; 543} 544 545#define LPM_DATA_SIZE_MAX 256 546#define LPM_DATA_SIZE_MIN 1 547 548#define LPM_VAL_SIZE_MAX (KMALLOC_MAX_SIZE - LPM_DATA_SIZE_MAX - \ 549 sizeof(struct lpm_trie_node)) 550#define LPM_VAL_SIZE_MIN 1 551 552#define LPM_KEY_SIZE(X) (sizeof(struct bpf_lpm_trie_key_u8) + (X)) 553#define LPM_KEY_SIZE_MAX LPM_KEY_SIZE(LPM_DATA_SIZE_MAX) 554#define LPM_KEY_SIZE_MIN LPM_KEY_SIZE(LPM_DATA_SIZE_MIN) 555 556#define LPM_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_NUMA_NODE | \ 557 BPF_F_ACCESS_MASK) 558 559static struct bpf_map *trie_alloc(union bpf_attr *attr) 560{ 561 struct lpm_trie *trie; 562 563 /* check sanity of attributes */ 564 if (attr->max_entries == 0 || 565 !(attr->map_flags & BPF_F_NO_PREALLOC) || 566 attr->map_flags & ~LPM_CREATE_FLAG_MASK || 567 !bpf_map_flags_access_ok(attr->map_flags) || 568 attr->key_size < LPM_KEY_SIZE_MIN || 569 attr->key_size > LPM_KEY_SIZE_MAX || 570 attr->value_size < LPM_VAL_SIZE_MIN || 571 attr->value_size > LPM_VAL_SIZE_MAX) 572 return ERR_PTR(-EINVAL); 573 574 trie = bpf_map_area_alloc(sizeof(*trie), NUMA_NO_NODE); 575 if (!trie) 576 return ERR_PTR(-ENOMEM); 577 578 /* copy mandatory map attributes */ 579 bpf_map_init_from_attr(&trie->map, attr); 580 trie->data_size = attr->key_size - 581 offsetof(struct bpf_lpm_trie_key_u8, data); 582 trie->max_prefixlen = trie->data_size * 8; 583 584 spin_lock_init(&trie->lock); 585 586 return &trie->map; 587} 588 589static void trie_free(struct bpf_map *map) 590{ 591 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 592 struct lpm_trie_node __rcu **slot; 593 struct lpm_trie_node *node; 594 595 /* Always start at the root and walk down to a node that has no 596 * children. Then free that node, nullify its reference in the parent 597 * and start over. 598 */ 599 600 for (;;) { 601 slot = &trie->root; 602 603 for (;;) { 604 node = rcu_dereference_protected(*slot, 1); 605 if (!node) 606 goto out; 607 608 if (rcu_access_pointer(node->child[0])) { 609 slot = &node->child[0]; 610 continue; 611 } 612 613 if (rcu_access_pointer(node->child[1])) { 614 slot = &node->child[1]; 615 continue; 616 } 617 618 kfree(node); 619 RCU_INIT_POINTER(*slot, NULL); 620 break; 621 } 622 } 623 624out: 625 bpf_map_area_free(trie); 626} 627 628static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key) 629{ 630 struct lpm_trie_node *node, *next_node = NULL, *parent, *search_root; 631 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 632 struct bpf_lpm_trie_key_u8 *key = _key, *next_key = _next_key; 633 struct lpm_trie_node **node_stack = NULL; 634 int err = 0, stack_ptr = -1; 635 unsigned int next_bit; 636 size_t matchlen; 637 638 /* The get_next_key follows postorder. For the 4 node example in 639 * the top of this file, the trie_get_next_key() returns the following 640 * one after another: 641 * 192.168.0.0/24 642 * 192.168.1.0/24 643 * 192.168.128.0/24 644 * 192.168.0.0/16 645 * 646 * The idea is to return more specific keys before less specific ones. 647 */ 648 649 /* Empty trie */ 650 search_root = rcu_dereference(trie->root); 651 if (!search_root) 652 return -ENOENT; 653 654 /* For invalid key, find the leftmost node in the trie */ 655 if (!key || key->prefixlen > trie->max_prefixlen) 656 goto find_leftmost; 657 658 node_stack = kmalloc_array(trie->max_prefixlen, 659 sizeof(struct lpm_trie_node *), 660 GFP_ATOMIC | __GFP_NOWARN); 661 if (!node_stack) 662 return -ENOMEM; 663 664 /* Try to find the exact node for the given key */ 665 for (node = search_root; node;) { 666 node_stack[++stack_ptr] = node; 667 matchlen = longest_prefix_match(trie, node, key); 668 if (node->prefixlen != matchlen || 669 node->prefixlen == key->prefixlen) 670 break; 671 672 next_bit = extract_bit(key->data, node->prefixlen); 673 node = rcu_dereference(node->child[next_bit]); 674 } 675 if (!node || node->prefixlen != key->prefixlen || 676 (node->flags & LPM_TREE_NODE_FLAG_IM)) 677 goto find_leftmost; 678 679 /* The node with the exactly-matching key has been found, 680 * find the first node in postorder after the matched node. 681 */ 682 node = node_stack[stack_ptr]; 683 while (stack_ptr > 0) { 684 parent = node_stack[stack_ptr - 1]; 685 if (rcu_dereference(parent->child[0]) == node) { 686 search_root = rcu_dereference(parent->child[1]); 687 if (search_root) 688 goto find_leftmost; 689 } 690 if (!(parent->flags & LPM_TREE_NODE_FLAG_IM)) { 691 next_node = parent; 692 goto do_copy; 693 } 694 695 node = parent; 696 stack_ptr--; 697 } 698 699 /* did not find anything */ 700 err = -ENOENT; 701 goto free_stack; 702 703find_leftmost: 704 /* Find the leftmost non-intermediate node, all intermediate nodes 705 * have exact two children, so this function will never return NULL. 706 */ 707 for (node = search_root; node;) { 708 if (node->flags & LPM_TREE_NODE_FLAG_IM) { 709 node = rcu_dereference(node->child[0]); 710 } else { 711 next_node = node; 712 node = rcu_dereference(node->child[0]); 713 if (!node) 714 node = rcu_dereference(next_node->child[1]); 715 } 716 } 717do_copy: 718 next_key->prefixlen = next_node->prefixlen; 719 memcpy((void *)next_key + offsetof(struct bpf_lpm_trie_key_u8, data), 720 next_node->data, trie->data_size); 721free_stack: 722 kfree(node_stack); 723 return err; 724} 725 726static int trie_check_btf(const struct bpf_map *map, 727 const struct btf *btf, 728 const struct btf_type *key_type, 729 const struct btf_type *value_type) 730{ 731 /* Keys must have struct bpf_lpm_trie_key_u8 embedded. */ 732 return BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ? 733 -EINVAL : 0; 734} 735 736static u64 trie_mem_usage(const struct bpf_map *map) 737{ 738 struct lpm_trie *trie = container_of(map, struct lpm_trie, map); 739 u64 elem_size; 740 741 elem_size = sizeof(struct lpm_trie_node) + trie->data_size + 742 trie->map.value_size; 743 return elem_size * READ_ONCE(trie->n_entries); 744} 745 746BTF_ID_LIST_SINGLE(trie_map_btf_ids, struct, lpm_trie) 747const struct bpf_map_ops trie_map_ops = { 748 .map_meta_equal = bpf_map_meta_equal, 749 .map_alloc = trie_alloc, 750 .map_free = trie_free, 751 .map_get_next_key = trie_get_next_key, 752 .map_lookup_elem = trie_lookup_elem, 753 .map_update_elem = trie_update_elem, 754 .map_delete_elem = trie_delete_elem, 755 .map_lookup_batch = generic_map_lookup_batch, 756 .map_update_batch = generic_map_update_batch, 757 .map_delete_batch = generic_map_delete_batch, 758 .map_check_btf = trie_check_btf, 759 .map_mem_usage = trie_mem_usage, 760 .map_btf_id = &trie_map_btf_ids[0], 761}; 762