1 /* 2 * Copyright (c) 2007-2013 Nicira, Inc. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of version 2 of the GNU General Public 6 * License as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 16 * 02110-1301, USA 17 */ 18 19 #include "flow.h" 20 #include "datapath.h" 21 #include <linux/uaccess.h> 22 #include <linux/netdevice.h> 23 #include <linux/etherdevice.h> 24 #include <linux/if_ether.h> 25 #include <linux/if_vlan.h> 26 #include <net/llc_pdu.h> 27 #include <linux/kernel.h> 28 #include <linux/hash.h> 29 #include <linux/jiffies.h> 30 #include <linux/llc.h> 31 #include <linux/module.h> 32 #include <linux/in.h> 33 #include <linux/rcupdate.h> 34 #include <linux/if_arp.h> 35 #include <linux/ip.h> 36 #include <linux/ipv6.h> 37 #include <linux/sctp.h> 38 #include <linux/tcp.h> 39 #include <linux/udp.h> 40 #include <linux/icmp.h> 41 #include <linux/icmpv6.h> 42 #include <linux/rculist.h> 43 #include <net/ip.h> 44 #include <net/ipv6.h> 45 #include <net/ndisc.h> 46 47 #define TBL_MIN_BUCKETS 1024 48 #define REHASH_INTERVAL (10 * 60 * HZ) 49 50 static struct kmem_cache *flow_cache; 51 52 static u16 range_n_bytes(const struct sw_flow_key_range *range) 53 { 54 return range->end - range->start; 55 } 56 57 void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src, 58 const struct sw_flow_mask *mask) 59 { 60 const long *m = (const long *)((const u8 *)&mask->key + 61 mask->range.start); 62 const long *s = (const long *)((const u8 *)src + 63 mask->range.start); 64 long *d = (long *)((u8 *)dst + mask->range.start); 65 int i; 66 67 /* The memory outside of the 'mask->range' are not set since 68 * further operations on 'dst' only uses contents within 69 * 'mask->range'. 70 */ 71 for (i = 0; i < range_n_bytes(&mask->range); i += sizeof(long)) 72 *d++ = *s++ & *m++; 73 } 74 75 struct sw_flow *ovs_flow_alloc(void) 76 { 77 struct sw_flow *flow; 78 int cpu; 79 80 flow = kmem_cache_alloc(flow_cache, GFP_KERNEL); 81 if (!flow) 82 return ERR_PTR(-ENOMEM); 83 84 flow->sf_acts = NULL; 85 flow->mask = NULL; 86 87 flow->stats = alloc_percpu(struct flow_stats); 88 if (!flow->stats) 89 goto err; 90 91 for_each_possible_cpu(cpu) { 92 struct flow_stats *cpu_stats; 93 94 cpu_stats = per_cpu_ptr(flow->stats, cpu); 95 spin_lock_init(&cpu_stats->lock); 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(struct flow_table *table) 104 { 105 return table->count; 106 } 107 108 static struct flex_array *alloc_buckets(unsigned int n_buckets) 109 { 110 struct flex_array *buckets; 111 int i, err; 112 113 buckets = flex_array_alloc(sizeof(struct hlist_head), 114 n_buckets, GFP_KERNEL); 115 if (!buckets) 116 return NULL; 117 118 err = flex_array_prealloc(buckets, 0, n_buckets, GFP_KERNEL); 119 if (err) { 120 flex_array_free(buckets); 121 return NULL; 122 } 123 124 for (i = 0; i < n_buckets; i++) 125 INIT_HLIST_HEAD((struct hlist_head *) 126 flex_array_get(buckets, i)); 127 128 return buckets; 129 } 130 131 static void flow_free(struct sw_flow *flow) 132 { 133 kfree((struct sf_flow_acts __force *)flow->sf_acts); 134 free_percpu(flow->stats); 135 kmem_cache_free(flow_cache, flow); 136 } 137 138 static void rcu_free_flow_callback(struct rcu_head *rcu) 139 { 140 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu); 141 142 flow_free(flow); 143 } 144 145 void ovs_flow_free(struct sw_flow *flow, bool deferred) 146 { 147 if (!flow) 148 return; 149 150 if (flow->mask) { 151 struct sw_flow_mask *mask = flow->mask; 152 153 /* ovs-lock is required to protect mask-refcount and 154 * mask list. 155 */ 156 ASSERT_OVSL(); 157 BUG_ON(!mask->ref_count); 158 mask->ref_count--; 159 160 if (!mask->ref_count) { 161 list_del_rcu(&mask->list); 162 if (deferred) 163 kfree_rcu(mask, rcu); 164 else 165 kfree(mask); 166 } 167 } 168 169 if (deferred) 170 call_rcu(&flow->rcu, rcu_free_flow_callback); 171 else 172 flow_free(flow); 173 } 174 175 static void free_buckets(struct flex_array *buckets) 176 { 177 flex_array_free(buckets); 178 } 179 180 181 static void __table_instance_destroy(struct table_instance *ti) 182 { 183 free_buckets(ti->buckets); 184 kfree(ti); 185 } 186 187 static struct table_instance *table_instance_alloc(int new_size) 188 { 189 struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL); 190 191 if (!ti) 192 return NULL; 193 194 ti->buckets = alloc_buckets(new_size); 195 196 if (!ti->buckets) { 197 kfree(ti); 198 return NULL; 199 } 200 ti->n_buckets = new_size; 201 ti->node_ver = 0; 202 ti->keep_flows = false; 203 get_random_bytes(&ti->hash_seed, sizeof(u32)); 204 205 return ti; 206 } 207 208 int ovs_flow_tbl_init(struct flow_table *table) 209 { 210 struct table_instance *ti; 211 212 ti = table_instance_alloc(TBL_MIN_BUCKETS); 213 214 if (!ti) 215 return -ENOMEM; 216 217 rcu_assign_pointer(table->ti, ti); 218 INIT_LIST_HEAD(&table->mask_list); 219 table->last_rehash = jiffies; 220 table->count = 0; 221 return 0; 222 } 223 224 static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu) 225 { 226 struct table_instance *ti = container_of(rcu, struct table_instance, rcu); 227 228 __table_instance_destroy(ti); 229 } 230 231 static void table_instance_destroy(struct table_instance *ti, bool deferred) 232 { 233 int i; 234 235 if (!ti) 236 return; 237 238 if (ti->keep_flows) 239 goto skip_flows; 240 241 for (i = 0; i < ti->n_buckets; i++) { 242 struct sw_flow *flow; 243 struct hlist_head *head = flex_array_get(ti->buckets, i); 244 struct hlist_node *n; 245 int ver = ti->node_ver; 246 247 hlist_for_each_entry_safe(flow, n, head, hash_node[ver]) { 248 hlist_del_rcu(&flow->hash_node[ver]); 249 ovs_flow_free(flow, deferred); 250 } 251 } 252 253 skip_flows: 254 if (deferred) 255 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); 256 else 257 __table_instance_destroy(ti); 258 } 259 260 void ovs_flow_tbl_destroy(struct flow_table *table, bool deferred) 261 { 262 struct table_instance *ti = ovsl_dereference(table->ti); 263 264 table_instance_destroy(ti, deferred); 265 } 266 267 struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti, 268 u32 *bucket, u32 *last) 269 { 270 struct sw_flow *flow; 271 struct hlist_head *head; 272 int ver; 273 int i; 274 275 ver = ti->node_ver; 276 while (*bucket < ti->n_buckets) { 277 i = 0; 278 head = flex_array_get(ti->buckets, *bucket); 279 hlist_for_each_entry_rcu(flow, head, hash_node[ver]) { 280 if (i < *last) { 281 i++; 282 continue; 283 } 284 *last = i + 1; 285 return flow; 286 } 287 (*bucket)++; 288 *last = 0; 289 } 290 291 return NULL; 292 } 293 294 static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash) 295 { 296 hash = jhash_1word(hash, ti->hash_seed); 297 return flex_array_get(ti->buckets, 298 (hash & (ti->n_buckets - 1))); 299 } 300 301 static void table_instance_insert(struct table_instance *ti, struct sw_flow *flow) 302 { 303 struct hlist_head *head; 304 305 head = find_bucket(ti, flow->hash); 306 hlist_add_head_rcu(&flow->hash_node[ti->node_ver], head); 307 } 308 309 static void flow_table_copy_flows(struct table_instance *old, 310 struct table_instance *new) 311 { 312 int old_ver; 313 int i; 314 315 old_ver = old->node_ver; 316 new->node_ver = !old_ver; 317 318 /* Insert in new table. */ 319 for (i = 0; i < old->n_buckets; i++) { 320 struct sw_flow *flow; 321 struct hlist_head *head; 322 323 head = flex_array_get(old->buckets, i); 324 325 hlist_for_each_entry(flow, head, hash_node[old_ver]) 326 table_instance_insert(new, flow); 327 } 328 329 old->keep_flows = true; 330 } 331 332 static struct table_instance *table_instance_rehash(struct table_instance *ti, 333 int n_buckets) 334 { 335 struct table_instance *new_ti; 336 337 new_ti = table_instance_alloc(n_buckets); 338 if (!new_ti) 339 return NULL; 340 341 flow_table_copy_flows(ti, new_ti); 342 343 return new_ti; 344 } 345 346 int ovs_flow_tbl_flush(struct flow_table *flow_table) 347 { 348 struct table_instance *old_ti; 349 struct table_instance *new_ti; 350 351 old_ti = ovsl_dereference(flow_table->ti); 352 new_ti = table_instance_alloc(TBL_MIN_BUCKETS); 353 if (!new_ti) 354 return -ENOMEM; 355 356 rcu_assign_pointer(flow_table->ti, new_ti); 357 flow_table->last_rehash = jiffies; 358 flow_table->count = 0; 359 360 table_instance_destroy(old_ti, true); 361 return 0; 362 } 363 364 static u32 flow_hash(const struct sw_flow_key *key, int key_start, 365 int key_end) 366 { 367 const u32 *hash_key = (const u32 *)((const u8 *)key + key_start); 368 int hash_u32s = (key_end - key_start) >> 2; 369 370 /* Make sure number of hash bytes are multiple of u32. */ 371 BUILD_BUG_ON(sizeof(long) % sizeof(u32)); 372 373 return arch_fast_hash2(hash_key, hash_u32s, 0); 374 } 375 376 static int flow_key_start(const struct sw_flow_key *key) 377 { 378 if (key->tun_key.ipv4_dst) 379 return 0; 380 else 381 return rounddown(offsetof(struct sw_flow_key, phy), 382 sizeof(long)); 383 } 384 385 static bool cmp_key(const struct sw_flow_key *key1, 386 const struct sw_flow_key *key2, 387 int key_start, int key_end) 388 { 389 const long *cp1 = (const long *)((const u8 *)key1 + key_start); 390 const long *cp2 = (const long *)((const u8 *)key2 + key_start); 391 long diffs = 0; 392 int i; 393 394 for (i = key_start; i < key_end; i += sizeof(long)) 395 diffs |= *cp1++ ^ *cp2++; 396 397 return diffs == 0; 398 } 399 400 static bool flow_cmp_masked_key(const struct sw_flow *flow, 401 const struct sw_flow_key *key, 402 int key_start, int key_end) 403 { 404 return cmp_key(&flow->key, key, key_start, key_end); 405 } 406 407 bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow, 408 struct sw_flow_match *match) 409 { 410 struct sw_flow_key *key = match->key; 411 int key_start = flow_key_start(key); 412 int key_end = match->range.end; 413 414 return cmp_key(&flow->unmasked_key, key, key_start, key_end); 415 } 416 417 static struct sw_flow *masked_flow_lookup(struct table_instance *ti, 418 const struct sw_flow_key *unmasked, 419 struct sw_flow_mask *mask) 420 { 421 struct sw_flow *flow; 422 struct hlist_head *head; 423 int key_start = mask->range.start; 424 int key_end = mask->range.end; 425 u32 hash; 426 struct sw_flow_key masked_key; 427 428 ovs_flow_mask_key(&masked_key, unmasked, mask); 429 hash = flow_hash(&masked_key, key_start, key_end); 430 head = find_bucket(ti, hash); 431 hlist_for_each_entry_rcu(flow, head, hash_node[ti->node_ver]) { 432 if (flow->mask == mask && flow->hash == hash && 433 flow_cmp_masked_key(flow, &masked_key, 434 key_start, key_end)) 435 return flow; 436 } 437 return NULL; 438 } 439 440 struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl, 441 const struct sw_flow_key *key, 442 u32 *n_mask_hit) 443 { 444 struct table_instance *ti = rcu_dereference_ovsl(tbl->ti); 445 struct sw_flow_mask *mask; 446 struct sw_flow *flow; 447 448 *n_mask_hit = 0; 449 list_for_each_entry_rcu(mask, &tbl->mask_list, list) { 450 (*n_mask_hit)++; 451 flow = masked_flow_lookup(ti, key, mask); 452 if (flow) /* Found */ 453 return flow; 454 } 455 return NULL; 456 } 457 458 struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl, 459 const struct sw_flow_key *key) 460 { 461 u32 __always_unused n_mask_hit; 462 463 return ovs_flow_tbl_lookup_stats(tbl, key, &n_mask_hit); 464 } 465 466 int ovs_flow_tbl_num_masks(const struct flow_table *table) 467 { 468 struct sw_flow_mask *mask; 469 int num = 0; 470 471 list_for_each_entry(mask, &table->mask_list, list) 472 num++; 473 474 return num; 475 } 476 477 static struct table_instance *table_instance_expand(struct table_instance *ti) 478 { 479 return table_instance_rehash(ti, ti->n_buckets * 2); 480 } 481 482 void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow) 483 { 484 struct table_instance *ti = ovsl_dereference(table->ti); 485 486 BUG_ON(table->count == 0); 487 hlist_del_rcu(&flow->hash_node[ti->node_ver]); 488 table->count--; 489 } 490 491 static struct sw_flow_mask *mask_alloc(void) 492 { 493 struct sw_flow_mask *mask; 494 495 mask = kmalloc(sizeof(*mask), GFP_KERNEL); 496 if (mask) 497 mask->ref_count = 1; 498 499 return mask; 500 } 501 502 static bool mask_equal(const struct sw_flow_mask *a, 503 const struct sw_flow_mask *b) 504 { 505 const u8 *a_ = (const u8 *)&a->key + a->range.start; 506 const u8 *b_ = (const u8 *)&b->key + b->range.start; 507 508 return (a->range.end == b->range.end) 509 && (a->range.start == b->range.start) 510 && (memcmp(a_, b_, range_n_bytes(&a->range)) == 0); 511 } 512 513 static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl, 514 const struct sw_flow_mask *mask) 515 { 516 struct list_head *ml; 517 518 list_for_each(ml, &tbl->mask_list) { 519 struct sw_flow_mask *m; 520 m = container_of(ml, struct sw_flow_mask, list); 521 if (mask_equal(mask, m)) 522 return m; 523 } 524 525 return NULL; 526 } 527 528 /* Add 'mask' into the mask list, if it is not already there. */ 529 static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow, 530 struct sw_flow_mask *new) 531 { 532 struct sw_flow_mask *mask; 533 mask = flow_mask_find(tbl, new); 534 if (!mask) { 535 /* Allocate a new mask if none exsits. */ 536 mask = mask_alloc(); 537 if (!mask) 538 return -ENOMEM; 539 mask->key = new->key; 540 mask->range = new->range; 541 list_add_rcu(&mask->list, &tbl->mask_list); 542 } else { 543 BUG_ON(!mask->ref_count); 544 mask->ref_count++; 545 } 546 547 flow->mask = mask; 548 return 0; 549 } 550 551 int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow, 552 struct sw_flow_mask *mask) 553 { 554 struct table_instance *new_ti = NULL; 555 struct table_instance *ti; 556 int err; 557 558 err = flow_mask_insert(table, flow, mask); 559 if (err) 560 return err; 561 562 flow->hash = flow_hash(&flow->key, flow->mask->range.start, 563 flow->mask->range.end); 564 ti = ovsl_dereference(table->ti); 565 table_instance_insert(ti, flow); 566 table->count++; 567 568 /* Expand table, if necessary, to make room. */ 569 if (table->count > ti->n_buckets) 570 new_ti = table_instance_expand(ti); 571 else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL)) 572 new_ti = table_instance_rehash(ti, ti->n_buckets); 573 574 if (new_ti) { 575 rcu_assign_pointer(table->ti, new_ti); 576 table_instance_destroy(ti, true); 577 table->last_rehash = jiffies; 578 } 579 return 0; 580 } 581 582 /* Initializes the flow module. 583 * Returns zero if successful or a negative error code. */ 584 int ovs_flow_init(void) 585 { 586 BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long)); 587 BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long)); 588 589 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0, 590 0, NULL); 591 if (flow_cache == NULL) 592 return -ENOMEM; 593 594 return 0; 595 } 596 597 /* Uninitializes the flow module. */ 598 void ovs_flow_exit(void) 599 { 600 kmem_cache_destroy(flow_cache); 601 } 602