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 /* Caller must update n_flows. */
  79 static int do_delete(struct sw_flow **bucket, struct sw_flow *flow)
  80 {
  81         rcu_assign_pointer(*bucket, NULL);
  82         flow_deferred_free(flow);
  83         return 1;
  84 }
  85
  86 /* Returns number of deleted flows.  We can ignore the priority
  87  * argument, since all exact-match entries are the same (highest)
  88  * priority. */
  89 static int table_hash_delete(struct sw_table *swt,
  90                                                          const struct sw_flow_key *key,
  91                                                          uint16_t priority, int strict)
  92 {
  93         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  94         unsigned int count = 0;
  95
  96         if (key->wildcards == 0) {
  97                 struct sw_flow **bucket = find_bucket(swt, key);
  98                 struct sw_flow *flow = *bucket;
  99                 if (flow && flow_keys_equal(&flow->key, key))
 100                         count = do_delete(bucket, flow);
 101         } else {
 102                 unsigned int i;
 103
 104                 for (i = 0; i <= th->bucket_mask; i++) {
 105                         struct sw_flow **bucket = &th->buckets[i];
 106                         struct sw_flow *flow = *bucket;
 107                         if (flow && flow_del_matches(&flow->key, key, strict))
 108                                 count += do_delete(bucket, flow);
 109                 }
 110         }
 111         th->n_flows -= count;
 112         return count;
 113 }
 114
 115 static int table_hash_timeout(struct datapath *dp, struct sw_table *swt)
 116 {
 117         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 118         unsigned int i;
 119         int count = 0;
 120
 121         mutex_lock(&dp_mutex);
 122         for (i = 0; i <= th->bucket_mask; i++) {
 123                 struct sw_flow **bucket = &th->buckets[i];
 124                 struct sw_flow *flow = *bucket;
 125                 if (flow) {
 126                         int reason = flow_timeout(flow);
 127                         if (reason >= 0) {
 128                                 count += do_delete(bucket, flow);
 129                                 dp_send_flow_expired(dp, flow, reason);
 130                         }
 131                 }
 132         }
 133         th->n_flows -= count;
 134         mutex_unlock(&dp_mutex);
 135
 136         return count;
 137 }
 138
 139 static void table_hash_destroy(struct sw_table *swt)
 140 {
 141         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 142         unsigned int i;
 143         for (i = 0; i <= th->bucket_mask; i++)
 144         if (th->buckets[i])
 145                 flow_free(th->buckets[i]);
 146         kmem_free(th->buckets, (th->bucket_mask + 1) * sizeof *th->buckets);
 147         kfree(th);
 148 }
 149
 150 static int table_hash_iterate(struct sw_table *swt,
 151                               const struct sw_flow_key *key,
 152                               struct sw_table_position *position,
 153                               int (*callback)(struct sw_flow *, void *private),
 154                               void *private)
 155 {
 156         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 157
 158         if (position->private[0] > th->bucket_mask)
 159                 return 0;
 160
 161         if (key->wildcards == 0) {
 162                 struct sw_flow *flow;
 163                 int error;
 164
 165                 flow = table_hash_lookup(swt, key);
 166                 if (!flow)
 167                         return 0;
 168
 169                 error = callback(flow, private);
 170                 if (!error)
 171                         position->private[0] = -1;
 172                 return error;
 173         } else {
 174                 int i;
 175
 176                 for (i = position->private[0]; i <= th->bucket_mask; i++) {
 177                         struct sw_flow *flow = th->buckets[i];
 178                         if (flow && flow_matches_1wild(&flow->key, key)) {
 179                                 int error = callback(flow, private);
 180                                 if (error) {
 181                                         position->private[0] = i;
 182                                         return error;
 183                                 }
 184                         }
 185                 }
 186                 return 0;
 187         }
 188 }
 189 static void table_hash_stats(struct sw_table *swt,
 190                                  struct sw_table_stats *stats)
 191 {
 192         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 193         stats->name = "hash";
 194         stats->wildcards = 0;          /* No wildcards are supported. */
 195         stats->n_flows   = th->n_flows;
 196         stats->max_flows = th->bucket_mask + 1;
 197         stats->n_matched = swt->n_matched;
 198 }
 199
 200 struct sw_table *table_hash_create(unsigned int polynomial,
 201                         unsigned int n_buckets)
 202 {
 203         struct sw_table_hash *th;
 204         struct sw_table *swt;
 205
 206         th = kzalloc(sizeof *th, GFP_KERNEL);
 207         if (th == NULL)
 208                 return NULL;
 209
 210         BUG_ON(n_buckets & (n_buckets - 1));
 211         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 212         if (th->buckets == NULL) {
 213                 printk("failed to allocate %u buckets\n", n_buckets);
 214                 kfree(th);
 215                 return NULL;
 216         }
 217         th->bucket_mask = n_buckets - 1;
 218
 219         swt = &th->swt;
 220         swt->lookup = table_hash_lookup;
 221         swt->insert = table_hash_insert;
 222         swt->delete = table_hash_delete;
 223         swt->timeout = table_hash_timeout;
 224         swt->destroy = table_hash_destroy;
 225         swt->iterate = table_hash_iterate;
 226         swt->stats = table_hash_stats;
 227
 228         crc32_init(&th->crc32, polynomial);
 229         th->n_flows = 0;
 230
 231         return swt;
 232 }
 233
 234 /* Double-hashing table. */
 235
 236 struct sw_table_hash2 {
 237         struct sw_table swt;
 238         struct sw_table *subtable[2];
 239 };
 240
 241 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 242                                                                                   const struct sw_flow_key *key)
 243 {
 244         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 245         int i;
 246
 247         for (i = 0; i < 2; i++) {
 248                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 249                 if (flow && flow_keys_equal(&flow->key, key))
 250                         return flow;
 251         }
 252         return NULL;
 253 }
 254
 255 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 256 {
 257         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 258
 259         if (table_hash_insert(t2->subtable[0], flow))
 260                 return 1;
 261         return table_hash_insert(t2->subtable[1], flow);
 262 }
 263
 264 static int table_hash2_delete(struct sw_table *swt,
 265                                                           const struct sw_flow_key *key,
 266                                                           uint16_t priority, int strict)
 267 {
 268         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 269         return (table_hash_delete(t2->subtable[0], key, priority, strict)
 270                         + table_hash_delete(t2->subtable[1], key, priority, strict));
 271 }
 272
 273 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 274 {
 275         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 276         return (table_hash_timeout(dp, t2->subtable[0])
 277                         + table_hash_timeout(dp, t2->subtable[1]));
 278 }
 279
 280 static void table_hash2_destroy(struct sw_table *swt)
 281 {
 282         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 283         table_hash_destroy(t2->subtable[0]);
 284         table_hash_destroy(t2->subtable[1]);
 285         kfree(t2);
 286 }
 287
 288 static int table_hash2_iterate(struct sw_table *swt,
 289                                const struct sw_flow_key *key,
 290                                struct sw_table_position *position,
 291                                int (*callback)(struct sw_flow *, void *),
 292                                void *private)
 293 {
 294         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 295         int i;
 296
 297         for (i = position->private[1]; i < 2; i++) {
 298                 int error = table_hash_iterate(t2->subtable[i], key, position,
 299                                                callback, private);
 300                 if (error) {
 301                         return error;
 302                 }
 303                 position->private[0] = 0;
 304                 position->private[1]++;
 305         }
 306         return 0;
 307 }
 308
 309 static void table_hash2_stats(struct sw_table *swt,
 310                                  struct sw_table_stats *stats)
 311 {
 312         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 313         struct sw_table_stats substats[2];
 314         int i;
 315
 316         for (i = 0; i < 2; i++)
 317                 table_hash_stats(t2->subtable[i], &substats[i]);
 318         stats->name = "hash2";
 319         stats->wildcards = 0;          /* No wildcards are supported. */
 320         stats->n_flows   = substats[0].n_flows + substats[1].n_flows;
 321         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 322         stats->n_matched = swt->n_matched;
 323 }
 324
 325 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 326                                                                         unsigned int poly1, unsigned int buckets1)
 327
 328 {
 329         struct sw_table_hash2 *t2;
 330         struct sw_table *swt;
 331
 332         t2 = kzalloc(sizeof *t2, GFP_KERNEL);
 333         if (t2 == NULL)
 334                 return NULL;
 335
 336         t2->subtable[0] = table_hash_create(poly0, buckets0);
 337         if (t2->subtable[0] == NULL)
 338                 goto out_free_t2;
 339
 340         t2->subtable[1] = table_hash_create(poly1, buckets1);
 341         if (t2->subtable[1] == NULL)
 342                 goto out_free_subtable0;
 343
 344         swt = &t2->swt;
 345         swt->lookup = table_hash2_lookup;
 346         swt->insert = table_hash2_insert;
 347         swt->delete = table_hash2_delete;
 348         swt->timeout = table_hash2_timeout;
 349         swt->destroy = table_hash2_destroy;
 350         swt->iterate = table_hash2_iterate;
 351         swt->stats = table_hash2_stats;
 352
 353         return swt;
 354
 355 out_free_subtable0:
 356         table_hash_destroy(t2->subtable[0]);
 357 out_free_t2:
 358         kfree(t2);
 359         return NULL;
 360 }
 361
 362 /* From fs/xfs/linux-2.4/kmem.c. */
 363
 364 static void *
 365 kmem_alloc(size_t size)
 366 {
 367         void *ptr;
 368
 369 #ifdef KMALLOC_MAX_SIZE
 370         if (size > KMALLOC_MAX_SIZE)
 371                 return NULL;
 372 #endif
 373         ptr = kmalloc(size, GFP_KERNEL);
 374         if (!ptr) {
 375                 ptr = vmalloc(size);
 376                 if (ptr)
 377                         printk("openflow: used vmalloc for %lu bytes\n",
 378                                         (unsigned long)size);
 379         }
 380         return ptr;
 381 }
 382
 383 static void *
 384 kmem_zalloc(size_t size)
 385 {
 386         void *ptr = kmem_alloc(size);
 387         if (ptr)
 388                 memset(ptr, 0, size);
 389         return ptr;
 390 }
 391
 392 static void
 393 kmem_free(void *ptr, size_t size)
 394 {
 395         if (((unsigned long)ptr < VMALLOC_START) ||
 396                 ((unsigned long)ptr >= VMALLOC_END)) {
 397                 kfree(ptr);
 398         } else {
 399                 vfree(ptr);
 400         }
 401 }