1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2007-2014 Nicira, Inc. 4 */ 5 6 #include "flow.h" 7 #include "datapath.h" 8 #include "flow_netlink.h" 9 #include <linux/uaccess.h> 10 #include <linux/netdevice.h> 11 #include <linux/etherdevice.h> 12 #include <linux/if_ether.h> 13 #include <linux/if_vlan.h> 14 #include <net/llc_pdu.h> 15 #include <linux/kernel.h> 16 #include <linux/jhash.h> 17 #include <linux/jiffies.h> 18 #include <linux/llc.h> 19 #include <linux/module.h> 20 #include <linux/in.h> 21 #include <linux/rcupdate.h> 22 #include <linux/cpumask.h> 23 #include <linux/if_arp.h> 24 #include <linux/ip.h> 25 #include <linux/ipv6.h> 26 #include <linux/sctp.h> 27 #include <linux/tcp.h> 28 #include <linux/udp.h> 29 #include <linux/icmp.h> 30 #include <linux/icmpv6.h> 31 #include <linux/rculist.h> 32 #include <linux/sort.h> 33 #include <net/ip.h> 34 #include <net/ipv6.h> 35 #include <net/ndisc.h> 36 37 #define TBL_MIN_BUCKETS 1024 38 #define MASK_ARRAY_SIZE_MIN 16 39 #define REHASH_INTERVAL (10 * 60 * HZ) 40 41 #define MC_DEFAULT_HASH_ENTRIES 256 42 #define MC_HASH_SHIFT 8 43 #define MC_HASH_SEGS ((sizeof(uint32_t) * 8) / MC_HASH_SHIFT) 44 45 static struct kmem_cache *flow_cache; 46 struct kmem_cache *flow_stats_cache __read_mostly; 47 48 static u16 range_n_bytes(const struct sw_flow_key_range *range) 49 { 50 return range->end - range->start; 51 } 52 53 void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src, 54 bool full, const struct sw_flow_mask *mask) 55 { 56 int start = full ? 0 : mask->range.start; 57 int len = full ? sizeof *dst : range_n_bytes(&mask->range); 58 const long *m = (const long *)((const u8 *)&mask->key + start); 59 const long *s = (const long *)((const u8 *)src + start); 60 long *d = (long *)((u8 *)dst + start); 61 int i; 62 63 /* If 'full' is true then all of 'dst' is fully initialized. Otherwise, 64 * if 'full' is false the memory outside of the 'mask->range' is left 65 * uninitialized. This can be used as an optimization when further 66 * operations on 'dst' only use contents within 'mask->range'. 67 */ 68 for (i = 0; i < len; i += sizeof(long)) 69 *d++ = *s++ & *m++; 70 } 71 72 struct sw_flow *ovs_flow_alloc(void) 73 { 74 struct sw_flow *flow; 75 struct sw_flow_stats *stats; 76 77 flow = kmem_cache_zalloc(flow_cache, GFP_KERNEL); 78 if (!flow) 79 return ERR_PTR(-ENOMEM); 80 81 flow->stats_last_writer = -1; 82 flow->cpu_used_mask = (struct cpumask *)&flow->stats[nr_cpu_ids]; 83 84 /* Initialize the default stat node. */ 85 stats = kmem_cache_alloc_node(flow_stats_cache, 86 GFP_KERNEL | __GFP_ZERO, 87 node_online(0) ? 0 : NUMA_NO_NODE); 88 if (!stats) 89 goto err; 90 91 spin_lock_init(&stats->lock); 92 93 RCU_INIT_POINTER(flow->stats[0], stats); 94 95 cpumask_set_cpu(0, flow->cpu_used_mask); 96 97 return flow; 98 err: 99 kmem_cache_free(flow_cache, flow); 100 return ERR_PTR(-ENOMEM); 101 } 102 103 int ovs_flow_tbl_count(const struct flow_table *table) 104 { 105 return table->count; 106 } 107 108 static void flow_free(struct sw_flow *flow) 109 { 110 unsigned int cpu; 111 112 if (ovs_identifier_is_key(&flow->id)) 113 kfree(flow->id.unmasked_key); 114 if (flow->sf_acts) 115 ovs_nla_free_flow_actions((struct sw_flow_actions __force *) 116 flow->sf_acts); 117 118 for_each_cpu(cpu, flow->cpu_used_mask) { 119 if (flow->stats[cpu]) 120 kmem_cache_free(flow_stats_cache, 121 (struct sw_flow_stats __force *)flow->stats[cpu]); 122 } 123 124 kmem_cache_free(flow_cache, flow); 125 } 126 127 static void rcu_free_flow_callback(struct rcu_head *rcu) 128 { 129 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu); 130 131 flow_free(flow); 132 } 133 134 void ovs_flow_free(struct sw_flow *flow, bool deferred) 135 { 136 if (!flow) 137 return; 138 139 if (deferred) 140 call_rcu(&flow->rcu, rcu_free_flow_callback); 141 else 142 flow_free(flow); 143 } 144 145 static void __table_instance_destroy(struct table_instance *ti) 146 { 147 kvfree(ti->buckets); 148 kfree(ti); 149 } 150 151 static struct table_instance *table_instance_alloc(int new_size) 152 { 153 struct table_instance *ti = kmalloc_obj(*ti); 154 int i; 155 156 if (!ti) 157 return NULL; 158 159 ti->buckets = kvmalloc_objs(struct hlist_head, new_size); 160 if (!ti->buckets) { 161 kfree(ti); 162 return NULL; 163 } 164 165 for (i = 0; i < new_size; i++) 166 INIT_HLIST_HEAD(&ti->buckets[i]); 167 168 ti->n_buckets = new_size; 169 ti->node_ver = 0; 170 ti->hash_seed = get_random_u32(); 171 172 return ti; 173 } 174 175 static void __mask_array_destroy(struct mask_array *ma) 176 { 177 free_percpu(ma->masks_usage_stats); 178 kfree(ma); 179 } 180 181 static void mask_array_rcu_cb(struct rcu_head *rcu) 182 { 183 struct mask_array *ma = container_of(rcu, struct mask_array, rcu); 184 185 __mask_array_destroy(ma); 186 } 187 188 static void tbl_mask_array_reset_counters(struct mask_array *ma) 189 { 190 int i, cpu; 191 192 /* As the per CPU counters are not atomic we can not go ahead and 193 * reset them from another CPU. To be able to still have an approximate 194 * zero based counter we store the value at reset, and subtract it 195 * later when processing. 196 */ 197 for (i = 0; i < ma->max; i++) { 198 ma->masks_usage_zero_cntr[i] = 0; 199 200 for_each_possible_cpu(cpu) { 201 struct mask_array_stats *stats; 202 unsigned int start; 203 u64 counter; 204 205 stats = per_cpu_ptr(ma->masks_usage_stats, cpu); 206 do { 207 start = u64_stats_fetch_begin(&stats->syncp); 208 counter = stats->usage_cntrs[i]; 209 } while (u64_stats_fetch_retry(&stats->syncp, start)); 210 211 ma->masks_usage_zero_cntr[i] += counter; 212 } 213 } 214 } 215 216 static struct mask_array *tbl_mask_array_alloc(int size) 217 { 218 struct mask_array *new; 219 220 size = max(MASK_ARRAY_SIZE_MIN, size); 221 new = kzalloc(struct_size(new, masks, size) + 222 sizeof(u64) * size, GFP_KERNEL); 223 if (!new) 224 return NULL; 225 226 new->masks_usage_zero_cntr = (u64 *)((u8 *)new + 227 struct_size(new, masks, size)); 228 229 new->masks_usage_stats = __alloc_percpu(sizeof(struct mask_array_stats) + 230 sizeof(u64) * size, 231 __alignof__(u64)); 232 if (!new->masks_usage_stats) { 233 kfree(new); 234 return NULL; 235 } 236 237 new->count = 0; 238 new->max = size; 239 240 return new; 241 } 242 243 static int tbl_mask_array_realloc(struct flow_table *tbl, int size) 244 { 245 struct mask_array *old; 246 struct mask_array *new; 247 248 new = tbl_mask_array_alloc(size); 249 if (!new) 250 return -ENOMEM; 251 252 old = ovsl_dereference(tbl->mask_array); 253 if (old) { 254 int i; 255 256 for (i = 0; i < old->max; i++) { 257 if (ovsl_dereference(old->masks[i])) 258 new->masks[new->count++] = old->masks[i]; 259 } 260 } 261 262 rcu_assign_pointer(tbl->mask_array, new); 263 264 if (old) 265 call_rcu(&old->rcu, mask_array_rcu_cb); 266 267 return 0; 268 } 269 270 static int tbl_mask_array_add_mask(struct flow_table *tbl, 271 struct sw_flow_mask *new) 272 { 273 struct mask_array *ma = ovsl_dereference(tbl->mask_array); 274 int err, ma_count = READ_ONCE(ma->count); 275 276 if (ma_count >= ma->max) { 277 err = tbl_mask_array_realloc(tbl, ma->max + 278 MASK_ARRAY_SIZE_MIN); 279 if (err) 280 return err; 281 282 ma = ovsl_dereference(tbl->mask_array); 283 } else { 284 /* On every add or delete we need to reset the counters so 285 * every new mask gets a fair chance of being prioritized. 286 */ 287 tbl_mask_array_reset_counters(ma); 288 } 289 290 BUG_ON(ovsl_dereference(ma->masks[ma_count])); 291 292 rcu_assign_pointer(ma->masks[ma_count], new); 293 WRITE_ONCE(ma->count, ma_count + 1); 294 295 return 0; 296 } 297 298 static void tbl_mask_array_del_mask(struct flow_table *tbl, 299 struct sw_flow_mask *mask) 300 { 301 struct mask_array *ma = ovsl_dereference(tbl->mask_array); 302 int i, ma_count = READ_ONCE(ma->count); 303 304 /* Remove the deleted mask pointers from the array */ 305 for (i = 0; i < ma_count; i++) { 306 if (mask == ovsl_dereference(ma->masks[i])) 307 goto found; 308 } 309 310 BUG(); 311 return; 312 313 found: 314 WRITE_ONCE(ma->count, ma_count - 1); 315 316 rcu_assign_pointer(ma->masks[i], ma->masks[ma_count - 1]); 317 RCU_INIT_POINTER(ma->masks[ma_count - 1], NULL); 318 319 kfree_rcu(mask, rcu); 320 321 /* Shrink the mask array if necessary. */ 322 if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) && 323 ma_count <= (ma->max / 3)) 324 tbl_mask_array_realloc(tbl, ma->max / 2); 325 else 326 tbl_mask_array_reset_counters(ma); 327 328 } 329 330 /* Remove 'mask' from the mask list, if it is not needed any more. */ 331 static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask) 332 { 333 if (mask) { 334 /* ovs-lock is required to protect mask-refcount and 335 * mask list. 336 */ 337 ASSERT_OVSL(); 338 BUG_ON(!mask->ref_count); 339 mask->ref_count--; 340 341 if (!mask->ref_count) 342 tbl_mask_array_del_mask(tbl, mask); 343 } 344 } 345 346 static void __mask_cache_destroy(struct mask_cache *mc) 347 { 348 free_percpu(mc->mask_cache); 349 kfree(mc); 350 } 351 352 static void mask_cache_rcu_cb(struct rcu_head *rcu) 353 { 354 struct mask_cache *mc = container_of(rcu, struct mask_cache, rcu); 355 356 __mask_cache_destroy(mc); 357 } 358 359 static struct mask_cache *tbl_mask_cache_alloc(u32 size) 360 { 361 struct mask_cache_entry __percpu *cache = NULL; 362 struct mask_cache *new; 363 364 /* Only allow size to be 0, or a power of 2, and does not exceed 365 * percpu allocation size. 366 */ 367 if ((!is_power_of_2(size) && size != 0) || 368 (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE) 369 return NULL; 370 371 new = kzalloc_obj(*new); 372 if (!new) 373 return NULL; 374 375 new->cache_size = size; 376 if (new->cache_size > 0) { 377 cache = __alloc_percpu(array_size(sizeof(struct mask_cache_entry), 378 new->cache_size), 379 __alignof__(struct mask_cache_entry)); 380 if (!cache) { 381 kfree(new); 382 return NULL; 383 } 384 } 385 386 new->mask_cache = cache; 387 return new; 388 } 389 int ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size) 390 { 391 struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache); 392 struct mask_cache *new; 393 394 if (size == mc->cache_size) 395 return 0; 396 397 if ((!is_power_of_2(size) && size != 0) || 398 (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE) 399 return -EINVAL; 400 401 new = tbl_mask_cache_alloc(size); 402 if (!new) 403 return -ENOMEM; 404 405 rcu_assign_pointer(table->mask_cache, new); 406 call_rcu(&mc->rcu, mask_cache_rcu_cb); 407 408 return 0; 409 } 410 411 int ovs_flow_tbl_init(struct flow_table *table) 412 { 413 struct table_instance *ti, *ufid_ti; 414 struct mask_cache *mc; 415 struct mask_array *ma; 416 417 mc = tbl_mask_cache_alloc(MC_DEFAULT_HASH_ENTRIES); 418 if (!mc) 419 return -ENOMEM; 420 421 ma = tbl_mask_array_alloc(MASK_ARRAY_SIZE_MIN); 422 if (!ma) 423 goto free_mask_cache; 424 425 ti = table_instance_alloc(TBL_MIN_BUCKETS); 426 if (!ti) 427 goto free_mask_array; 428 429 ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS); 430 if (!ufid_ti) 431 goto free_ti; 432 433 rcu_assign_pointer(table->ti, ti); 434 rcu_assign_pointer(table->ufid_ti, ufid_ti); 435 rcu_assign_pointer(table->mask_array, ma); 436 rcu_assign_pointer(table->mask_cache, mc); 437 table->last_rehash = jiffies; 438 table->count = 0; 439 table->ufid_count = 0; 440 return 0; 441 442 free_ti: 443 __table_instance_destroy(ti); 444 free_mask_array: 445 __mask_array_destroy(ma); 446 free_mask_cache: 447 __mask_cache_destroy(mc); 448 return -ENOMEM; 449 } 450 451 static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu) 452 { 453 struct table_instance *ti; 454 455 ti = container_of(rcu, struct table_instance, rcu); 456 __table_instance_destroy(ti); 457 } 458 459 static void table_instance_flow_free(struct flow_table *table, 460 struct table_instance *ti, 461 struct table_instance *ufid_ti, 462 struct sw_flow *flow) 463 { 464 hlist_del_rcu(&flow->flow_table.node[ti->node_ver]); 465 table->count--; 466 467 if (ovs_identifier_is_ufid(&flow->id)) { 468 hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]); 469 table->ufid_count--; 470 } 471 472 flow_mask_remove(table, flow->mask); 473 } 474 475 /* Must be called with OVS mutex held. */ 476 void table_instance_flow_flush(struct flow_table *table, 477 struct table_instance *ti, 478 struct table_instance *ufid_ti) 479 { 480 int i; 481 482 for (i = 0; i < ti->n_buckets; i++) { 483 struct hlist_head *head = &ti->buckets[i]; 484 struct hlist_node *n; 485 struct sw_flow *flow; 486 487 hlist_for_each_entry_safe(flow, n, head, 488 flow_table.node[ti->node_ver]) { 489 490 table_instance_flow_free(table, ti, ufid_ti, 491 flow); 492 ovs_flow_free(flow, true); 493 } 494 } 495 496 if (WARN_ON(table->count != 0 || 497 table->ufid_count != 0)) { 498 table->count = 0; 499 table->ufid_count = 0; 500 } 501 } 502 503 static void table_instance_destroy(struct table_instance *ti, 504 struct table_instance *ufid_ti) 505 { 506 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); 507 call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb); 508 } 509 510 /* No need for locking this function is called from RCU callback or 511 * error path. 512 */ 513 void ovs_flow_tbl_destroy(struct flow_table *table) 514 { 515 struct table_instance *ti = rcu_dereference_raw(table->ti); 516 struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti); 517 struct mask_cache *mc = rcu_dereference_raw(table->mask_cache); 518 struct mask_array *ma = rcu_dereference_raw(table->mask_array); 519 520 call_rcu(&mc->rcu, mask_cache_rcu_cb); 521 call_rcu(&ma->rcu, mask_array_rcu_cb); 522 table_instance_destroy(ti, ufid_ti); 523 } 524 525 struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti, 526 u32 *bucket, u32 *last) 527 { 528 struct sw_flow *flow; 529 struct hlist_head *head; 530 int ver; 531 int i; 532 533 ver = ti->node_ver; 534 while (*bucket < ti->n_buckets) { 535 i = 0; 536 head = &ti->buckets[*bucket]; 537 hlist_for_each_entry_rcu(flow, head, flow_table.node[ver]) { 538 if (i < *last) { 539 i++; 540 continue; 541 } 542 *last = i + 1; 543 return flow; 544 } 545 (*bucket)++; 546 *last = 0; 547 } 548 549 return NULL; 550 } 551 552 static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash) 553 { 554 hash = jhash_1word(hash, ti->hash_seed); 555 return &ti->buckets[hash & (ti->n_buckets - 1)]; 556 } 557 558 static void table_instance_insert(struct table_instance *ti, 559 struct sw_flow *flow) 560 { 561 struct hlist_head *head; 562 563 head = find_bucket(ti, flow->flow_table.hash); 564 hlist_add_head_rcu(&flow->flow_table.node[ti->node_ver], head); 565 } 566 567 static void ufid_table_instance_insert(struct table_instance *ti, 568 struct sw_flow *flow) 569 { 570 struct hlist_head *head; 571 572 head = find_bucket(ti, flow->ufid_table.hash); 573 hlist_add_head_rcu(&flow->ufid_table.node[ti->node_ver], head); 574 } 575 576 static void flow_table_copy_flows(struct table_instance *old, 577 struct table_instance *new, bool ufid) 578 { 579 int old_ver; 580 int i; 581 582 old_ver = old->node_ver; 583 new->node_ver = !old_ver; 584 585 /* Insert in new table. */ 586 for (i = 0; i < old->n_buckets; i++) { 587 struct sw_flow *flow; 588 struct hlist_head *head = &old->buckets[i]; 589 590 if (ufid) 591 hlist_for_each_entry_rcu(flow, head, 592 ufid_table.node[old_ver], 593 lockdep_ovsl_is_held()) 594 ufid_table_instance_insert(new, flow); 595 else 596 hlist_for_each_entry_rcu(flow, head, 597 flow_table.node[old_ver], 598 lockdep_ovsl_is_held()) 599 table_instance_insert(new, flow); 600 } 601 } 602 603 static struct table_instance *table_instance_rehash(struct table_instance *ti, 604 int n_buckets, bool ufid) 605 { 606 struct table_instance *new_ti; 607 608 new_ti = table_instance_alloc(n_buckets); 609 if (!new_ti) 610 return NULL; 611 612 flow_table_copy_flows(ti, new_ti, ufid); 613 614 return new_ti; 615 } 616 617 int ovs_flow_tbl_flush(struct flow_table *flow_table) 618 { 619 struct table_instance *old_ti, *new_ti; 620 struct table_instance *old_ufid_ti, *new_ufid_ti; 621 622 new_ti = table_instance_alloc(TBL_MIN_BUCKETS); 623 if (!new_ti) 624 return -ENOMEM; 625 new_ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS); 626 if (!new_ufid_ti) 627 goto err_free_ti; 628 629 old_ti = ovsl_dereference(flow_table->ti); 630 old_ufid_ti = ovsl_dereference(flow_table->ufid_ti); 631 632 rcu_assign_pointer(flow_table->ti, new_ti); 633 rcu_assign_pointer(flow_table->ufid_ti, new_ufid_ti); 634 flow_table->last_rehash = jiffies; 635 636 table_instance_flow_flush(flow_table, old_ti, old_ufid_ti); 637 table_instance_destroy(old_ti, old_ufid_ti); 638 return 0; 639 640 err_free_ti: 641 __table_instance_destroy(new_ti); 642 return -ENOMEM; 643 } 644 645 static u32 flow_hash(const struct sw_flow_key *key, 646 const struct sw_flow_key_range *range) 647 { 648 const u32 *hash_key = (const u32 *)((const u8 *)key + range->start); 649 650 /* Make sure number of hash bytes are multiple of u32. */ 651 int hash_u32s = range_n_bytes(range) >> 2; 652 653 return jhash2(hash_key, hash_u32s, 0); 654 } 655 656 static int flow_key_start(const struct sw_flow_key *key) 657 { 658 if (key->tun_proto) 659 return 0; 660 else 661 return rounddown(offsetof(struct sw_flow_key, phy), 662 sizeof(long)); 663 } 664 665 static bool cmp_key(const struct sw_flow_key *key1, 666 const struct sw_flow_key *key2, 667 int key_start, int key_end) 668 { 669 const long *cp1 = (const long *)((const u8 *)key1 + key_start); 670 const long *cp2 = (const long *)((const u8 *)key2 + key_start); 671 int i; 672 673 for (i = key_start; i < key_end; i += sizeof(long)) 674 if (*cp1++ ^ *cp2++) 675 return false; 676 677 return true; 678 } 679 680 static bool flow_cmp_masked_key(const struct sw_flow *flow, 681 const struct sw_flow_key *key, 682 const struct sw_flow_key_range *range) 683 { 684 return cmp_key(&flow->key, key, range->start, range->end); 685 } 686 687 static bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow, 688 const struct sw_flow_match *match) 689 { 690 struct sw_flow_key *key = match->key; 691 int key_start = flow_key_start(key); 692 int key_end = match->range.end; 693 694 BUG_ON(ovs_identifier_is_ufid(&flow->id)); 695 return cmp_key(flow->id.unmasked_key, key, key_start, key_end); 696 } 697 698 static struct sw_flow *masked_flow_lookup(struct table_instance *ti, 699 const struct sw_flow_key *unmasked, 700 const struct sw_flow_mask *mask, 701 u32 *n_mask_hit) 702 { 703 struct sw_flow *flow; 704 struct hlist_head *head; 705 u32 hash; 706 struct sw_flow_key masked_key; 707 708 ovs_flow_mask_key(&masked_key, unmasked, false, mask); 709 hash = flow_hash(&masked_key, &mask->range); 710 head = find_bucket(ti, hash); 711 (*n_mask_hit)++; 712 713 hlist_for_each_entry_rcu(flow, head, flow_table.node[ti->node_ver], 714 lockdep_ovsl_is_held()) { 715 if (flow->mask == mask && flow->flow_table.hash == hash && 716 flow_cmp_masked_key(flow, &masked_key, &mask->range)) 717 return flow; 718 } 719 return NULL; 720 } 721 722 /* Flow lookup does full lookup on flow table. It starts with 723 * mask from index passed in *index. 724 * This function MUST be called with BH disabled due to the use 725 * of CPU specific variables. 726 */ 727 static struct sw_flow *flow_lookup(struct flow_table *tbl, 728 struct table_instance *ti, 729 struct mask_array *ma, 730 const struct sw_flow_key *key, 731 u32 *n_mask_hit, 732 u32 *n_cache_hit, 733 u32 *index) 734 { 735 struct mask_array_stats *stats = this_cpu_ptr(ma->masks_usage_stats); 736 struct sw_flow *flow; 737 struct sw_flow_mask *mask; 738 int i; 739 740 if (likely(*index < ma->max)) { 741 mask = rcu_dereference_ovsl(ma->masks[*index]); 742 if (mask) { 743 flow = masked_flow_lookup(ti, key, mask, n_mask_hit); 744 if (flow) { 745 u64_stats_update_begin(&stats->syncp); 746 stats->usage_cntrs[*index]++; 747 u64_stats_update_end(&stats->syncp); 748 (*n_cache_hit)++; 749 return flow; 750 } 751 } 752 } 753 754 for (i = 0; i < ma->max; i++) { 755 756 if (i == *index) 757 continue; 758 759 mask = rcu_dereference_ovsl(ma->masks[i]); 760 if (unlikely(!mask)) 761 break; 762 763 flow = masked_flow_lookup(ti, key, mask, n_mask_hit); 764 if (flow) { /* Found */ 765 *index = i; 766 u64_stats_update_begin(&stats->syncp); 767 stats->usage_cntrs[*index]++; 768 u64_stats_update_end(&stats->syncp); 769 return flow; 770 } 771 } 772 773 return NULL; 774 } 775 776 /* 777 * mask_cache maps flow to probable mask. This cache is not tightly 778 * coupled cache, It means updates to mask list can result in inconsistent 779 * cache entry in mask cache. 780 * This is per cpu cache and is divided in MC_HASH_SEGS segments. 781 * In case of a hash collision the entry is hashed in next segment. 782 * */ 783 struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl, 784 const struct sw_flow_key *key, 785 u32 skb_hash, 786 u32 *n_mask_hit, 787 u32 *n_cache_hit) 788 { 789 struct mask_cache *mc = rcu_dereference(tbl->mask_cache); 790 struct mask_array *ma = rcu_dereference(tbl->mask_array); 791 struct table_instance *ti = rcu_dereference(tbl->ti); 792 struct mask_cache_entry *entries, *ce; 793 struct sw_flow *flow; 794 u32 hash; 795 int seg; 796 797 *n_mask_hit = 0; 798 *n_cache_hit = 0; 799 if (unlikely(!skb_hash || mc->cache_size == 0)) { 800 u32 mask_index = 0; 801 u32 cache = 0; 802 803 return flow_lookup(tbl, ti, ma, key, n_mask_hit, &cache, 804 &mask_index); 805 } 806 807 /* Pre and post recirulation flows usually have the same skb_hash 808 * value. To avoid hash collisions, rehash the 'skb_hash' with 809 * 'recirc_id'. */ 810 if (key->recirc_id) 811 skb_hash = jhash_1word(skb_hash, key->recirc_id); 812 813 ce = NULL; 814 hash = skb_hash; 815 entries = this_cpu_ptr(mc->mask_cache); 816 817 /* Find the cache entry 'ce' to operate on. */ 818 for (seg = 0; seg < MC_HASH_SEGS; seg++) { 819 int index = hash & (mc->cache_size - 1); 820 struct mask_cache_entry *e; 821 822 e = &entries[index]; 823 if (e->skb_hash == skb_hash) { 824 flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, 825 n_cache_hit, &e->mask_index); 826 if (!flow) 827 e->skb_hash = 0; 828 return flow; 829 } 830 831 if (!ce || e->skb_hash < ce->skb_hash) 832 ce = e; /* A better replacement cache candidate. */ 833 834 hash >>= MC_HASH_SHIFT; 835 } 836 837 /* Cache miss, do full lookup. */ 838 flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, n_cache_hit, 839 &ce->mask_index); 840 if (flow) 841 ce->skb_hash = skb_hash; 842 843 *n_cache_hit = 0; 844 return flow; 845 } 846 847 struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl, 848 const struct sw_flow_key *key) 849 { 850 struct table_instance *ti = rcu_dereference_ovsl(tbl->ti); 851 struct mask_array *ma = rcu_dereference_ovsl(tbl->mask_array); 852 u32 __always_unused n_mask_hit; 853 u32 __always_unused n_cache_hit; 854 struct sw_flow *flow; 855 u32 index = 0; 856 857 /* This function gets called trough the netlink interface and therefore 858 * is preemptible. However, flow_lookup() function needs to be called 859 * with BH disabled due to CPU specific variables. 860 */ 861 local_bh_disable(); 862 flow = flow_lookup(tbl, ti, ma, key, &n_mask_hit, &n_cache_hit, &index); 863 local_bh_enable(); 864 return flow; 865 } 866 867 struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl, 868 const struct sw_flow_match *match) 869 { 870 struct mask_array *ma = ovsl_dereference(tbl->mask_array); 871 int i; 872 873 /* Always called under ovs-mutex. */ 874 for (i = 0; i < ma->max; i++) { 875 struct table_instance *ti = rcu_dereference_ovsl(tbl->ti); 876 u32 __always_unused n_mask_hit; 877 struct sw_flow_mask *mask; 878 struct sw_flow *flow; 879 880 mask = ovsl_dereference(ma->masks[i]); 881 if (!mask) 882 continue; 883 884 flow = masked_flow_lookup(ti, match->key, mask, &n_mask_hit); 885 if (flow && ovs_identifier_is_key(&flow->id) && 886 ovs_flow_cmp_unmasked_key(flow, match)) { 887 return flow; 888 } 889 } 890 891 return NULL; 892 } 893 894 static u32 ufid_hash(const struct sw_flow_id *sfid) 895 { 896 return jhash(sfid->ufid, sfid->ufid_len, 0); 897 } 898 899 static bool ovs_flow_cmp_ufid(const struct sw_flow *flow, 900 const struct sw_flow_id *sfid) 901 { 902 if (flow->id.ufid_len != sfid->ufid_len) 903 return false; 904 905 return !memcmp(flow->id.ufid, sfid->ufid, sfid->ufid_len); 906 } 907 908 bool ovs_flow_cmp(const struct sw_flow *flow, 909 const struct sw_flow_match *match) 910 { 911 if (ovs_identifier_is_ufid(&flow->id)) 912 return flow_cmp_masked_key(flow, match->key, &match->range); 913 914 return ovs_flow_cmp_unmasked_key(flow, match); 915 } 916 917 struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl, 918 const struct sw_flow_id *ufid) 919 { 920 struct table_instance *ti = rcu_dereference_ovsl(tbl->ufid_ti); 921 struct sw_flow *flow; 922 struct hlist_head *head; 923 u32 hash; 924 925 hash = ufid_hash(ufid); 926 head = find_bucket(ti, hash); 927 hlist_for_each_entry_rcu(flow, head, ufid_table.node[ti->node_ver], 928 lockdep_ovsl_is_held()) { 929 if (flow->ufid_table.hash == hash && 930 ovs_flow_cmp_ufid(flow, ufid)) 931 return flow; 932 } 933 return NULL; 934 } 935 936 int ovs_flow_tbl_num_masks(const struct flow_table *table) 937 { 938 struct mask_array *ma = rcu_dereference_ovsl(table->mask_array); 939 return READ_ONCE(ma->count); 940 } 941 942 u32 ovs_flow_tbl_masks_cache_size(const struct flow_table *table) 943 { 944 struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache); 945 946 return READ_ONCE(mc->cache_size); 947 } 948 949 static struct table_instance *table_instance_expand(struct table_instance *ti, 950 bool ufid) 951 { 952 return table_instance_rehash(ti, ti->n_buckets * 2, ufid); 953 } 954 955 /* Must be called with OVS mutex held. */ 956 void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow) 957 { 958 struct table_instance *ti = ovsl_dereference(table->ti); 959 struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti); 960 961 BUG_ON(table->count == 0); 962 table_instance_flow_free(table, ti, ufid_ti, flow); 963 } 964 965 static struct sw_flow_mask *mask_alloc(void) 966 { 967 struct sw_flow_mask *mask; 968 969 mask = kmalloc_obj(*mask); 970 if (mask) 971 mask->ref_count = 1; 972 973 return mask; 974 } 975 976 static bool mask_equal(const struct sw_flow_mask *a, 977 const struct sw_flow_mask *b) 978 { 979 const u8 *a_ = (const u8 *)&a->key + a->range.start; 980 const u8 *b_ = (const u8 *)&b->key + b->range.start; 981 982 return (a->range.end == b->range.end) 983 && (a->range.start == b->range.start) 984 && (memcmp(a_, b_, range_n_bytes(&a->range)) == 0); 985 } 986 987 static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl, 988 const struct sw_flow_mask *mask) 989 { 990 struct mask_array *ma; 991 int i; 992 993 ma = ovsl_dereference(tbl->mask_array); 994 for (i = 0; i < ma->max; i++) { 995 struct sw_flow_mask *t; 996 t = ovsl_dereference(ma->masks[i]); 997 998 if (t && mask_equal(mask, t)) 999 return t; 1000 } 1001 1002 return NULL; 1003 } 1004 1005 /* Add 'mask' into the mask list, if it is not already there. */ 1006 static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow, 1007 const struct sw_flow_mask *new) 1008 { 1009 struct sw_flow_mask *mask; 1010 1011 mask = flow_mask_find(tbl, new); 1012 if (!mask) { 1013 /* Allocate a new mask if none exists. */ 1014 mask = mask_alloc(); 1015 if (!mask) 1016 return -ENOMEM; 1017 mask->key = new->key; 1018 mask->range = new->range; 1019 1020 /* Add mask to mask-list. */ 1021 if (tbl_mask_array_add_mask(tbl, mask)) { 1022 kfree(mask); 1023 return -ENOMEM; 1024 } 1025 } else { 1026 BUG_ON(!mask->ref_count); 1027 mask->ref_count++; 1028 } 1029 1030 flow->mask = mask; 1031 return 0; 1032 } 1033 1034 /* Must be called with OVS mutex held. */ 1035 static void flow_key_insert(struct flow_table *table, struct sw_flow *flow) 1036 { 1037 struct table_instance *new_ti = NULL; 1038 struct table_instance *ti; 1039 1040 flow->flow_table.hash = flow_hash(&flow->key, &flow->mask->range); 1041 ti = ovsl_dereference(table->ti); 1042 table_instance_insert(ti, flow); 1043 table->count++; 1044 1045 /* Expand table, if necessary, to make room. */ 1046 if (table->count > ti->n_buckets) 1047 new_ti = table_instance_expand(ti, false); 1048 else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL)) 1049 new_ti = table_instance_rehash(ti, ti->n_buckets, false); 1050 1051 if (new_ti) { 1052 rcu_assign_pointer(table->ti, new_ti); 1053 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); 1054 table->last_rehash = jiffies; 1055 } 1056 } 1057 1058 /* Must be called with OVS mutex held. */ 1059 static void flow_ufid_insert(struct flow_table *table, struct sw_flow *flow) 1060 { 1061 struct table_instance *ti; 1062 1063 flow->ufid_table.hash = ufid_hash(&flow->id); 1064 ti = ovsl_dereference(table->ufid_ti); 1065 ufid_table_instance_insert(ti, flow); 1066 table->ufid_count++; 1067 1068 /* Expand table, if necessary, to make room. */ 1069 if (table->ufid_count > ti->n_buckets) { 1070 struct table_instance *new_ti; 1071 1072 new_ti = table_instance_expand(ti, true); 1073 if (new_ti) { 1074 rcu_assign_pointer(table->ufid_ti, new_ti); 1075 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); 1076 } 1077 } 1078 } 1079 1080 /* Must be called with OVS mutex held. */ 1081 int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow, 1082 const struct sw_flow_mask *mask) 1083 { 1084 int err; 1085 1086 err = flow_mask_insert(table, flow, mask); 1087 if (err) 1088 return err; 1089 flow_key_insert(table, flow); 1090 if (ovs_identifier_is_ufid(&flow->id)) 1091 flow_ufid_insert(table, flow); 1092 1093 return 0; 1094 } 1095 1096 static int compare_mask_and_count(const void *a, const void *b) 1097 { 1098 const struct mask_count *mc_a = a; 1099 const struct mask_count *mc_b = b; 1100 1101 return (s64)mc_b->counter - (s64)mc_a->counter; 1102 } 1103 1104 /* Must be called with OVS mutex held. */ 1105 void ovs_flow_masks_rebalance(struct flow_table *table) 1106 { 1107 struct mask_array *ma = rcu_dereference_ovsl(table->mask_array); 1108 struct mask_count *masks_and_count; 1109 struct mask_array *new; 1110 int masks_entries = 0; 1111 int i; 1112 1113 /* Build array of all current entries with use counters. */ 1114 masks_and_count = kmalloc_objs(*masks_and_count, ma->max); 1115 if (!masks_and_count) 1116 return; 1117 1118 for (i = 0; i < ma->max; i++) { 1119 struct sw_flow_mask *mask; 1120 int cpu; 1121 1122 mask = rcu_dereference_ovsl(ma->masks[i]); 1123 if (unlikely(!mask)) 1124 break; 1125 1126 masks_and_count[i].index = i; 1127 masks_and_count[i].counter = 0; 1128 1129 for_each_possible_cpu(cpu) { 1130 struct mask_array_stats *stats; 1131 unsigned int start; 1132 u64 counter; 1133 1134 stats = per_cpu_ptr(ma->masks_usage_stats, cpu); 1135 do { 1136 start = u64_stats_fetch_begin(&stats->syncp); 1137 counter = stats->usage_cntrs[i]; 1138 } while (u64_stats_fetch_retry(&stats->syncp, start)); 1139 1140 masks_and_count[i].counter += counter; 1141 } 1142 1143 /* Subtract the zero count value. */ 1144 masks_and_count[i].counter -= ma->masks_usage_zero_cntr[i]; 1145 1146 /* Rather than calling tbl_mask_array_reset_counters() 1147 * below when no change is needed, do it inline here. 1148 */ 1149 ma->masks_usage_zero_cntr[i] += masks_and_count[i].counter; 1150 } 1151 1152 if (i == 0) 1153 goto free_mask_entries; 1154 1155 /* Sort the entries */ 1156 masks_entries = i; 1157 sort(masks_and_count, masks_entries, sizeof(*masks_and_count), 1158 compare_mask_and_count, NULL); 1159 1160 /* If the order is the same, nothing to do... */ 1161 for (i = 0; i < masks_entries; i++) { 1162 if (i != masks_and_count[i].index) 1163 break; 1164 } 1165 if (i == masks_entries) 1166 goto free_mask_entries; 1167 1168 /* Rebuilt the new list in order of usage. */ 1169 new = tbl_mask_array_alloc(ma->max); 1170 if (!new) 1171 goto free_mask_entries; 1172 1173 for (i = 0; i < masks_entries; i++) { 1174 int index = masks_and_count[i].index; 1175 1176 if (ovsl_dereference(ma->masks[index])) 1177 new->masks[new->count++] = ma->masks[index]; 1178 } 1179 1180 rcu_assign_pointer(table->mask_array, new); 1181 call_rcu(&ma->rcu, mask_array_rcu_cb); 1182 1183 free_mask_entries: 1184 kfree(masks_and_count); 1185 } 1186 1187 /* Initializes the flow module. 1188 * Returns zero if successful or a negative error code. */ 1189 int ovs_flow_init(void) 1190 { 1191 BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long)); 1192 BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long)); 1193 1194 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow) 1195 + (nr_cpu_ids 1196 * sizeof(struct sw_flow_stats *)) 1197 + cpumask_size(), 1198 0, 0, NULL); 1199 if (flow_cache == NULL) 1200 return -ENOMEM; 1201 1202 flow_stats_cache 1203 = kmem_cache_create("sw_flow_stats", sizeof(struct sw_flow_stats), 1204 0, SLAB_HWCACHE_ALIGN, NULL); 1205 if (flow_stats_cache == NULL) { 1206 kmem_cache_destroy(flow_cache); 1207 flow_cache = NULL; 1208 return -ENOMEM; 1209 } 1210 1211 return 0; 1212 } 1213 1214 /* Uninitializes the flow module. */ 1215 void ovs_flow_exit(void) 1216 { 1217 kmem_cache_destroy(flow_stats_cache); 1218 kmem_cache_destroy(flow_cache); 1219 } 1220