pintos-os.org Git - openvswitch/blob - datapath/table-hash.c

   1 /*
   2  * Distributed under the terms of the GNU GPL version 2.
   3  * Copyright (c) 2007, 2008 The Board of Trustees of The Leland
   4  * Stanford Junior University
   5  */
   6
   7 #include "table.h"
   8 #include "crc32.h"
   9 #include "flow.h"
  10 #include "datapath.h"
  11
  12 #include <linux/slab.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/mm.h>
  15 #include <linux/highmem.h>
  16 #include <asm/pgtable.h>
  17
  18 static void *kmem_alloc(size_t);
  19 static void *kmem_zalloc(size_t);
  20 static void kmem_free(void *, size_t);
  21
  22 struct sw_table_hash {
  23         struct sw_table swt;
  24         struct crc32 crc32;
  25         unsigned int n_flows;
  26         unsigned int bucket_mask; /* Number of buckets minus 1. */
  27         struct sw_flow **buckets;
  28 };
  29
  30 static struct sw_flow **find_bucket(struct sw_table *swt,
  31                                                                         const struct sw_flow_key *key)
  32 {
  33         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  34         unsigned int crc = crc32_calculate(&th->crc32, key,
  35                                 offsetof(struct sw_flow_key, wildcards));
  36         return &th->buckets[crc & th->bucket_mask];
  37 }
  38
  39 static struct sw_flow *table_hash_lookup(struct sw_table *swt,
  40                                                                                  const struct sw_flow_key *key)
  41 {
  42         struct sw_flow *flow = *find_bucket(swt, key);
  43         return flow && flow_keys_equal(&flow->key, key) ? flow : NULL;
  44 }
  45
  46 static int table_hash_insert(struct sw_table *swt, struct sw_flow *flow)
  47 {
  48         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  49         struct sw_flow **bucket;
  50         int retval;
  51
  52         if (flow->key.wildcards != 0)
  53                 return 0;
  54
  55         bucket = find_bucket(swt, &flow->key);
  56         if (*bucket == NULL) {
  57                 th->n_flows++;
  58                 rcu_assign_pointer(*bucket, flow);
  59                 retval = 1;
  60         } else {
  61                 struct sw_flow *old_flow = *bucket;
  62                 if (flow_keys_equal(&old_flow->key, &flow->key)) {
  63                         /* Keep stats from the original flow */
  64                         flow->init_time = old_flow->init_time;
  65                         flow->packet_count = old_flow->packet_count;
  66                         flow->byte_count = old_flow->byte_count;
  67
  68                         rcu_assign_pointer(*bucket, flow);
  69                         flow_deferred_free(old_flow);
  70                         retval = 1;
  71                 } else {
  72                         retval = 0;
  73                 }
  74         }
  75         return retval;
  76 }
  77
  78 static int table_hash_modify(struct sw_table *swt,
  79                 const struct sw_flow_key *key,
  80                 const struct ofp_action *actions, int n_actions)
  81 {
  82         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  83         unsigned int count = 0;
  84
  85         if (key->wildcards == 0) {
  86                 struct sw_flow **bucket = find_bucket(swt, key);
  87                 struct sw_flow *flow = *bucket;
  88                 if (flow && flow_matches_1wild(&flow->key, key)) {
  89                         flow_replace_acts(flow, actions, n_actions);
  90                         count = 1;
  91                 }
  92         } else {
  93                 unsigned int i;
  94
  95                 for (i = 0; i <= th->bucket_mask; i++) {
  96                         struct sw_flow **bucket = &th->buckets[i];
  97                         struct sw_flow *flow = *bucket;
  98                         if (flow && flow_matches_1wild(&flow->key, key)) {
  99                                 flow_replace_acts(flow, actions, n_actions);
 100                                 count++;
 101                         }
 102                 }
 103         }
 104         return count;
 105 }
 106
 107 /* Caller must update n_flows. */
 108 static int do_delete(struct sw_flow **bucket, struct sw_flow *flow)
 109 {
 110         rcu_assign_pointer(*bucket, NULL);
 111         flow_deferred_free(flow);
 112         return 1;
 113 }
 114
 115 /* Returns number of deleted flows.  We can ignore the priority
 116  * argument, since all exact-match entries are the same (highest)
 117  * priority. */
 118 static int table_hash_delete(struct sw_table *swt,
 119                                                          const struct sw_flow_key *key,
 120                                                          uint16_t priority, int strict)
 121 {
 122         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 123         unsigned int count = 0;
 124
 125         if (key->wildcards == 0) {
 126                 struct sw_flow **bucket = find_bucket(swt, key);
 127                 struct sw_flow *flow = *bucket;
 128                 if (flow && flow_keys_equal(&flow->key, key))
 129                         count = do_delete(bucket, flow);
 130         } else {
 131                 unsigned int i;
 132
 133                 for (i = 0; i <= th->bucket_mask; i++) {
 134                         struct sw_flow **bucket = &th->buckets[i];
 135                         struct sw_flow *flow = *bucket;
 136                         if (flow && flow_del_matches(&flow->key, key, strict))
 137                                 count += do_delete(bucket, flow);
 138                 }
 139         }
 140         th->n_flows -= count;
 141         return count;
 142 }
 143
 144 static int table_hash_timeout(struct datapath *dp, struct sw_table *swt)
 145 {
 146         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 147         unsigned int i;
 148         int count = 0;
 149
 150         mutex_lock(&dp_mutex);
 151         for (i = 0; i <= th->bucket_mask; i++) {
 152                 struct sw_flow **bucket = &th->buckets[i];
 153                 struct sw_flow *flow = *bucket;
 154                 if (flow) {
 155                         int reason = flow_timeout(flow);
 156                         if (reason >= 0) {
 157                                 count += do_delete(bucket, flow);
 158                                 dp_send_flow_expired(dp, flow, reason);
 159                         }
 160                 }
 161         }
 162         th->n_flows -= count;
 163         mutex_unlock(&dp_mutex);
 164
 165         return count;
 166 }
 167
 168 static void table_hash_destroy(struct sw_table *swt)
 169 {
 170         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 171         unsigned int i;
 172         for (i = 0; i <= th->bucket_mask; i++)
 173         if (th->buckets[i])
 174                 flow_free(th->buckets[i]);
 175         kmem_free(th->buckets, (th->bucket_mask + 1) * sizeof *th->buckets);
 176         kfree(th);
 177 }
 178
 179 static int table_hash_iterate(struct sw_table *swt,
 180                               const struct sw_flow_key *key,
 181                               struct sw_table_position *position,
 182                               int (*callback)(struct sw_flow *, void *private),
 183                               void *private)
 184 {
 185         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 186
 187         if (position->private[0] > th->bucket_mask)
 188                 return 0;
 189
 190         if (key->wildcards == 0) {
 191                 struct sw_flow *flow;
 192                 int error;
 193
 194                 flow = table_hash_lookup(swt, key);
 195                 if (!flow)
 196                         return 0;
 197
 198                 error = callback(flow, private);
 199                 if (!error)
 200                         position->private[0] = -1;
 201                 return error;
 202         } else {
 203                 int i;
 204
 205                 for (i = position->private[0]; i <= th->bucket_mask; i++) {
 206                         struct sw_flow *flow = th->buckets[i];
 207                         if (flow && flow_matches_1wild(&flow->key, key)) {
 208                                 int error = callback(flow, private);
 209                                 if (error) {
 210                                         position->private[0] = i;
 211                                         return error;
 212                                 }
 213                         }
 214                 }
 215                 return 0;
 216         }
 217 }
 218 static void table_hash_stats(struct sw_table *swt,
 219                                  struct sw_table_stats *stats)
 220 {
 221         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 222         stats->name = "hash";
 223         stats->wildcards = 0;          /* No wildcards are supported. */
 224         stats->n_flows   = th->n_flows;
 225         stats->max_flows = th->bucket_mask + 1;
 226         stats->n_matched = swt->n_matched;
 227 }
 228
 229 struct sw_table *table_hash_create(unsigned int polynomial,
 230                         unsigned int n_buckets)
 231 {
 232         struct sw_table_hash *th;
 233         struct sw_table *swt;
 234
 235         th = kzalloc(sizeof *th, GFP_KERNEL);
 236         if (th == NULL)
 237                 return NULL;
 238
 239         BUG_ON(n_buckets & (n_buckets - 1));
 240         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 241         if (th->buckets == NULL) {
 242                 printk("failed to allocate %u buckets\n", n_buckets);
 243                 kfree(th);
 244                 return NULL;
 245         }
 246         th->bucket_mask = n_buckets - 1;
 247
 248         swt = &th->swt;
 249         swt->lookup = table_hash_lookup;
 250         swt->insert = table_hash_insert;
 251         swt->delete = table_hash_delete;
 252         swt->timeout = table_hash_timeout;
 253         swt->destroy = table_hash_destroy;
 254         swt->iterate = table_hash_iterate;
 255         swt->stats = table_hash_stats;
 256
 257         crc32_init(&th->crc32, polynomial);
 258         th->n_flows = 0;
 259
 260         return swt;
 261 }
 262
 263 /* Double-hashing table. */
 264
 265 struct sw_table_hash2 {
 266         struct sw_table swt;
 267         struct sw_table *subtable[2];
 268 };
 269
 270 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 271                                                                                   const struct sw_flow_key *key)
 272 {
 273         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 274         int i;
 275
 276         for (i = 0; i < 2; i++) {
 277                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 278                 if (flow && flow_keys_equal(&flow->key, key))
 279                         return flow;
 280         }
 281         return NULL;
 282 }
 283
 284 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 285 {
 286         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 287
 288         if (table_hash_insert(t2->subtable[0], flow))
 289                 return 1;
 290         return table_hash_insert(t2->subtable[1], flow);
 291 }
 292
 293 static int table_hash2_modify(struct sw_table *swt,
 294                 const struct sw_flow_key *key,
 295                 const struct ofp_action *actions, int n_actions)
 296 {
 297         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 298         return (table_hash_modify(t2->subtable[0], key, actions, n_actions)
 299                         + table_hash_modify(t2->subtable[1], key, actions, n_actions));
 300 }
 301
 302 static int table_hash2_delete(struct sw_table *swt,
 303                                                           const struct sw_flow_key *key,
 304                                                           uint16_t priority, int strict)
 305 {
 306         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 307         return (table_hash_delete(t2->subtable[0], key, priority, strict)
 308                         + table_hash_delete(t2->subtable[1], key, priority, strict));
 309 }
 310
 311 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 312 {
 313         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 314         return (table_hash_timeout(dp, t2->subtable[0])
 315                         + table_hash_timeout(dp, t2->subtable[1]));
 316 }
 317
 318 static void table_hash2_destroy(struct sw_table *swt)
 319 {
 320         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 321         table_hash_destroy(t2->subtable[0]);
 322         table_hash_destroy(t2->subtable[1]);
 323         kfree(t2);
 324 }
 325
 326 static int table_hash2_iterate(struct sw_table *swt,
 327                                const struct sw_flow_key *key,
 328                                struct sw_table_position *position,
 329                                int (*callback)(struct sw_flow *, void *),
 330                                void *private)
 331 {
 332         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 333         int i;
 334
 335         for (i = position->private[1]; i < 2; i++) {
 336                 int error = table_hash_iterate(t2->subtable[i], key, position,
 337                                                callback, private);
 338                 if (error) {
 339                         return error;
 340                 }
 341                 position->private[0] = 0;
 342                 position->private[1]++;
 343         }
 344         return 0;
 345 }
 346
 347 static void table_hash2_stats(struct sw_table *swt,
 348                                  struct sw_table_stats *stats)
 349 {
 350         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 351         struct sw_table_stats substats[2];
 352         int i;
 353
 354         for (i = 0; i < 2; i++)
 355                 table_hash_stats(t2->subtable[i], &substats[i]);
 356         stats->name = "hash2";
 357         stats->wildcards = 0;          /* No wildcards are supported. */
 358         stats->n_flows   = substats[0].n_flows + substats[1].n_flows;
 359         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 360         stats->n_matched = swt->n_matched;
 361 }
 362
 363 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 364                                                                         unsigned int poly1, unsigned int buckets1)
 365
 366 {
 367         struct sw_table_hash2 *t2;
 368         struct sw_table *swt;
 369
 370         t2 = kzalloc(sizeof *t2, GFP_KERNEL);
 371         if (t2 == NULL)
 372                 return NULL;
 373
 374         t2->subtable[0] = table_hash_create(poly0, buckets0);
 375         if (t2->subtable[0] == NULL)
 376                 goto out_free_t2;
 377
 378         t2->subtable[1] = table_hash_create(poly1, buckets1);
 379         if (t2->subtable[1] == NULL)
 380                 goto out_free_subtable0;
 381
 382         swt = &t2->swt;
 383         swt->lookup = table_hash2_lookup;
 384         swt->insert = table_hash2_insert;
 385         swt->modify = table_hash2_modify;
 386         swt->delete = table_hash2_delete;
 387         swt->timeout = table_hash2_timeout;
 388         swt->destroy = table_hash2_destroy;
 389         swt->iterate = table_hash2_iterate;
 390         swt->stats = table_hash2_stats;
 391
 392         return swt;
 393
 394 out_free_subtable0:
 395         table_hash_destroy(t2->subtable[0]);
 396 out_free_t2:
 397         kfree(t2);
 398         return NULL;
 399 }
 400
 401 /* From fs/xfs/linux-2.4/kmem.c. */
 402
 403 static void *
 404 kmem_alloc(size_t size)
 405 {
 406         void *ptr;
 407
 408 #ifdef KMALLOC_MAX_SIZE
 409         if (size > KMALLOC_MAX_SIZE)
 410                 return NULL;
 411 #endif
 412         ptr = kmalloc(size, GFP_KERNEL);
 413         if (!ptr) {
 414                 ptr = vmalloc(size);
 415                 if (ptr)
 416                         printk("openflow: used vmalloc for %lu bytes\n",
 417                                         (unsigned long)size);
 418         }
 419         return ptr;
 420 }
 421
 422 static void *
 423 kmem_zalloc(size_t size)
 424 {
 425         void *ptr = kmem_alloc(size);
 426         if (ptr)
 427                 memset(ptr, 0, size);
 428         return ptr;
 429 }
 430
 431 static void
 432 kmem_free(void *ptr, size_t size)
 433 {
 434         if (((unsigned long)ptr < VMALLOC_START) ||
 435                 ((unsigned long)ptr >= VMALLOC_END)) {
 436                 kfree(ptr);
 437         } else {
 438                 vfree(ptr);
 439         }
 440 }