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