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/jhash.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 #include "datapath.h" 48 49 #define TBL_MIN_BUCKETS 1024 50 #define REHASH_INTERVAL (10 * 60 * HZ) 51 52 static struct kmem_cache *flow_cache; 53 54 static u16 range_n_bytes(const struct sw_flow_key_range *range) 55 { 56 return range->end - range->start; 57 } 58 59 void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src, 60 const struct sw_flow_mask *mask) 61 { 62 const long *m = (long *)((u8 *)&mask->key + mask->range.start); 63 const long *s = (long *)((u8 *)src + 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 79 flow = kmem_cache_alloc(flow_cache, GFP_KERNEL); 80 if (!flow) 81 return ERR_PTR(-ENOMEM); 82 83 spin_lock_init(&flow->lock); 84 flow->sf_acts = NULL; 85 flow->mask = NULL; 86 87 return flow; 88 } 89 90 int ovs_flow_tbl_count(struct flow_table *table) 91 { 92 return table->count; 93 } 94 95 static struct flex_array *alloc_buckets(unsigned int n_buckets) 96 { 97 struct flex_array *buckets; 98 int i, err; 99 100 buckets = flex_array_alloc(sizeof(struct hlist_head), 101 n_buckets, GFP_KERNEL); 102 if (!buckets) 103 return NULL; 104 105 err = flex_array_prealloc(buckets, 0, n_buckets, GFP_KERNEL); 106 if (err) { 107 flex_array_free(buckets); 108 return NULL; 109 } 110 111 for (i = 0; i < n_buckets; i++) 112 INIT_HLIST_HEAD((struct hlist_head *) 113 flex_array_get(buckets, i)); 114 115 return buckets; 116 } 117 118 static void flow_free(struct sw_flow *flow) 119 { 120 kfree((struct sf_flow_acts __force *)flow->sf_acts); 121 kmem_cache_free(flow_cache, flow); 122 } 123 124 static void rcu_free_flow_callback(struct rcu_head *rcu) 125 { 126 struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu); 127 128 flow_free(flow); 129 } 130 131 static void rcu_free_sw_flow_mask_cb(struct rcu_head *rcu) 132 { 133 struct sw_flow_mask *mask = container_of(rcu, struct sw_flow_mask, rcu); 134 135 kfree(mask); 136 } 137 138 static void flow_mask_del_ref(struct sw_flow_mask *mask, bool deferred) 139 { 140 if (!mask) 141 return; 142 143 BUG_ON(!mask->ref_count); 144 mask->ref_count--; 145 146 if (!mask->ref_count) { 147 list_del_rcu(&mask->list); 148 if (deferred) 149 call_rcu(&mask->rcu, rcu_free_sw_flow_mask_cb); 150 else 151 kfree(mask); 152 } 153 } 154 155 void ovs_flow_free(struct sw_flow *flow, bool deferred) 156 { 157 if (!flow) 158 return; 159 160 flow_mask_del_ref(flow->mask, deferred); 161 162 if (deferred) 163 call_rcu(&flow->rcu, rcu_free_flow_callback); 164 else 165 flow_free(flow); 166 } 167 168 static void free_buckets(struct flex_array *buckets) 169 { 170 flex_array_free(buckets); 171 } 172 173 static void __table_instance_destroy(struct table_instance *ti) 174 { 175 int i; 176 177 if (ti->keep_flows) 178 goto skip_flows; 179 180 for (i = 0; i < ti->n_buckets; i++) { 181 struct sw_flow *flow; 182 struct hlist_head *head = flex_array_get(ti->buckets, i); 183 struct hlist_node *n; 184 int ver = ti->node_ver; 185 186 hlist_for_each_entry_safe(flow, n, head, hash_node[ver]) { 187 hlist_del(&flow->hash_node[ver]); 188 ovs_flow_free(flow, false); 189 } 190 } 191 192 skip_flows: 193 free_buckets(ti->buckets); 194 kfree(ti); 195 } 196 197 static struct table_instance *table_instance_alloc(int new_size) 198 { 199 struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL); 200 201 if (!ti) 202 return NULL; 203 204 ti->buckets = alloc_buckets(new_size); 205 206 if (!ti->buckets) { 207 kfree(ti); 208 return NULL; 209 } 210 ti->n_buckets = new_size; 211 ti->node_ver = 0; 212 ti->keep_flows = false; 213 get_random_bytes(&ti->hash_seed, sizeof(u32)); 214 215 return ti; 216 } 217 218 int ovs_flow_tbl_init(struct flow_table *table) 219 { 220 struct table_instance *ti; 221 222 ti = table_instance_alloc(TBL_MIN_BUCKETS); 223 224 if (!ti) 225 return -ENOMEM; 226 227 rcu_assign_pointer(table->ti, ti); 228 INIT_LIST_HEAD(&table->mask_list); 229 table->last_rehash = jiffies; 230 table->count = 0; 231 return 0; 232 } 233 234 static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu) 235 { 236 struct table_instance *ti = container_of(rcu, struct table_instance, rcu); 237 238 __table_instance_destroy(ti); 239 } 240 241 static void table_instance_destroy(struct table_instance *ti, bool deferred) 242 { 243 if (!ti) 244 return; 245 246 if (deferred) 247 call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); 248 else 249 __table_instance_destroy(ti); 250 } 251 252 void ovs_flow_tbl_destroy(struct flow_table *table) 253 { 254 struct table_instance *ti = ovsl_dereference(table->ti); 255 256 table_instance_destroy(ti, false); 257 } 258 259 struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti, 260 u32 *bucket, u32 *last) 261 { 262 struct sw_flow *flow; 263 struct hlist_head *head; 264 int ver; 265 int i; 266 267 ver = ti->node_ver; 268 while (*bucket < ti->n_buckets) { 269 i = 0; 270 head = flex_array_get(ti->buckets, *bucket); 271 hlist_for_each_entry_rcu(flow, head, hash_node[ver]) { 272 if (i < *last) { 273 i++; 274 continue; 275 } 276 *last = i + 1; 277 return flow; 278 } 279 (*bucket)++; 280 *last = 0; 281 } 282 283 return NULL; 284 } 285 286 static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash) 287 { 288 hash = jhash_1word(hash, ti->hash_seed); 289 return flex_array_get(ti->buckets, 290 (hash & (ti->n_buckets - 1))); 291 } 292 293 static void table_instance_insert(struct table_instance *ti, struct sw_flow *flow) 294 { 295 struct hlist_head *head; 296 297 head = find_bucket(ti, flow->hash); 298 hlist_add_head_rcu(&flow->hash_node[ti->node_ver], head); 299 } 300 301 static void flow_table_copy_flows(struct table_instance *old, 302 struct table_instance *new) 303 { 304 int old_ver; 305 int i; 306 307 old_ver = old->node_ver; 308 new->node_ver = !old_ver; 309 310 /* Insert in new table. */ 311 for (i = 0; i < old->n_buckets; i++) { 312 struct sw_flow *flow; 313 struct hlist_head *head; 314 315 head = flex_array_get(old->buckets, i); 316 317 hlist_for_each_entry(flow, head, hash_node[old_ver]) 318 table_instance_insert(new, flow); 319 } 320 321 old->keep_flows = true; 322 } 323 324 static struct table_instance *table_instance_rehash(struct table_instance *ti, 325 int n_buckets) 326 { 327 struct table_instance *new_ti; 328 329 new_ti = table_instance_alloc(n_buckets); 330 if (!new_ti) 331 return NULL; 332 333 flow_table_copy_flows(ti, new_ti); 334 335 return new_ti; 336 } 337 338 int ovs_flow_tbl_flush(struct flow_table *flow_table) 339 { 340 struct table_instance *old_ti; 341 struct table_instance *new_ti; 342 343 old_ti = ovsl_dereference(flow_table->ti); 344 new_ti = table_instance_alloc(TBL_MIN_BUCKETS); 345 if (!new_ti) 346 return -ENOMEM; 347 348 rcu_assign_pointer(flow_table->ti, new_ti); 349 flow_table->last_rehash = jiffies; 350 flow_table->count = 0; 351 352 table_instance_destroy(old_ti, true); 353 return 0; 354 } 355 356 static u32 flow_hash(const struct sw_flow_key *key, int key_start, 357 int key_end) 358 { 359 u32 *hash_key = (u32 *)((u8 *)key + key_start); 360 int hash_u32s = (key_end - key_start) >> 2; 361 362 /* Make sure number of hash bytes are multiple of u32. */ 363 BUILD_BUG_ON(sizeof(long) % sizeof(u32)); 364 365 return jhash2(hash_key, hash_u32s, 0); 366 } 367 368 static int flow_key_start(const struct sw_flow_key *key) 369 { 370 if (key->tun_key.ipv4_dst) 371 return 0; 372 else 373 return rounddown(offsetof(struct sw_flow_key, phy), 374 sizeof(long)); 375 } 376 377 static bool cmp_key(const struct sw_flow_key *key1, 378 const struct sw_flow_key *key2, 379 int key_start, int key_end) 380 { 381 const long *cp1 = (long *)((u8 *)key1 + key_start); 382 const long *cp2 = (long *)((u8 *)key2 + key_start); 383 long diffs = 0; 384 int i; 385 386 for (i = key_start; i < key_end; i += sizeof(long)) 387 diffs |= *cp1++ ^ *cp2++; 388 389 return diffs == 0; 390 } 391 392 static bool flow_cmp_masked_key(const struct sw_flow *flow, 393 const struct sw_flow_key *key, 394 int key_start, int key_end) 395 { 396 return cmp_key(&flow->key, key, key_start, key_end); 397 } 398 399 bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow, 400 struct sw_flow_match *match) 401 { 402 struct sw_flow_key *key = match->key; 403 int key_start = flow_key_start(key); 404 int key_end = match->range.end; 405 406 return cmp_key(&flow->unmasked_key, key, key_start, key_end); 407 } 408 409 static struct sw_flow *masked_flow_lookup(struct table_instance *ti, 410 const struct sw_flow_key *unmasked, 411 struct sw_flow_mask *mask) 412 { 413 struct sw_flow *flow; 414 struct hlist_head *head; 415 int key_start = mask->range.start; 416 int key_end = mask->range.end; 417 u32 hash; 418 struct sw_flow_key masked_key; 419 420 ovs_flow_mask_key(&masked_key, unmasked, mask); 421 hash = flow_hash(&masked_key, key_start, key_end); 422 head = find_bucket(ti, hash); 423 hlist_for_each_entry_rcu(flow, head, hash_node[ti->node_ver]) { 424 if (flow->mask == mask && flow->hash == hash && 425 flow_cmp_masked_key(flow, &masked_key, 426 key_start, key_end)) 427 return flow; 428 } 429 return NULL; 430 } 431 432 struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl, 433 const struct sw_flow_key *key, 434 u32 *n_mask_hit) 435 { 436 struct table_instance *ti = rcu_dereference(tbl->ti); 437 struct sw_flow_mask *mask; 438 struct sw_flow *flow; 439 440 *n_mask_hit = 0; 441 list_for_each_entry_rcu(mask, &tbl->mask_list, list) { 442 (*n_mask_hit)++; 443 flow = masked_flow_lookup(ti, key, mask); 444 if (flow) /* Found */ 445 return flow; 446 } 447 return NULL; 448 } 449 450 int ovs_flow_tbl_num_masks(const struct flow_table *table) 451 { 452 struct sw_flow_mask *mask; 453 int num = 0; 454 455 list_for_each_entry(mask, &table->mask_list, list) 456 num++; 457 458 return num; 459 } 460 461 static struct table_instance *table_instance_expand(struct table_instance *ti) 462 { 463 return table_instance_rehash(ti, ti->n_buckets * 2); 464 } 465 466 void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow) 467 { 468 struct table_instance *ti = ovsl_dereference(table->ti); 469 470 BUG_ON(table->count == 0); 471 hlist_del_rcu(&flow->hash_node[ti->node_ver]); 472 table->count--; 473 } 474 475 static struct sw_flow_mask *mask_alloc(void) 476 { 477 struct sw_flow_mask *mask; 478 479 mask = kmalloc(sizeof(*mask), GFP_KERNEL); 480 if (mask) 481 mask->ref_count = 0; 482 483 return mask; 484 } 485 486 static void mask_add_ref(struct sw_flow_mask *mask) 487 { 488 mask->ref_count++; 489 } 490 491 static bool mask_equal(const struct sw_flow_mask *a, 492 const struct sw_flow_mask *b) 493 { 494 u8 *a_ = (u8 *)&a->key + a->range.start; 495 u8 *b_ = (u8 *)&b->key + b->range.start; 496 497 return (a->range.end == b->range.end) 498 && (a->range.start == b->range.start) 499 && (memcmp(a_, b_, range_n_bytes(&a->range)) == 0); 500 } 501 502 static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl, 503 const struct sw_flow_mask *mask) 504 { 505 struct list_head *ml; 506 507 list_for_each(ml, &tbl->mask_list) { 508 struct sw_flow_mask *m; 509 m = container_of(ml, struct sw_flow_mask, list); 510 if (mask_equal(mask, m)) 511 return m; 512 } 513 514 return NULL; 515 } 516 517 /** 518 * add a new mask into the mask list. 519 * The caller needs to make sure that 'mask' is not the same 520 * as any masks that are already on the list. 521 */ 522 static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow, 523 struct sw_flow_mask *new) 524 { 525 struct sw_flow_mask *mask; 526 mask = flow_mask_find(tbl, new); 527 if (!mask) { 528 /* Allocate a new mask if none exsits. */ 529 mask = mask_alloc(); 530 if (!mask) 531 return -ENOMEM; 532 mask->key = new->key; 533 mask->range = new->range; 534 list_add_rcu(&mask->list, &tbl->mask_list); 535 } 536 537 mask_add_ref(mask); 538 flow->mask = mask; 539 return 0; 540 } 541 542 int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow, 543 struct sw_flow_mask *mask) 544 { 545 struct table_instance *new_ti = NULL; 546 struct table_instance *ti; 547 int err; 548 549 err = flow_mask_insert(table, flow, mask); 550 if (err) 551 return err; 552 553 flow->hash = flow_hash(&flow->key, flow->mask->range.start, 554 flow->mask->range.end); 555 ti = ovsl_dereference(table->ti); 556 table_instance_insert(ti, flow); 557 table->count++; 558 559 /* Expand table, if necessary, to make room. */ 560 if (table->count > ti->n_buckets) 561 new_ti = table_instance_expand(ti); 562 else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL)) 563 new_ti = table_instance_rehash(ti, ti->n_buckets); 564 565 if (new_ti) { 566 rcu_assign_pointer(table->ti, new_ti); 567 table_instance_destroy(ti, true); 568 table->last_rehash = jiffies; 569 } 570 return 0; 571 } 572 573 /* Initializes the flow module. 574 * Returns zero if successful or a negative error code. */ 575 int ovs_flow_init(void) 576 { 577 BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long)); 578 BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long)); 579 580 flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0, 581 0, NULL); 582 if (flow_cache == NULL) 583 return -ENOMEM; 584 585 return 0; 586 } 587 588 /* Uninitializes the flow module. */ 589 void ovs_flow_exit(void) 590 { 591 kmem_cache_destroy(flow_cache); 592 } 593