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                         rcu_assign_pointer(*bucket, flow);
  64                         flow_deferred_free(old_flow);
  65                         retval = 1;
  66                 } else {
  67                         retval = 0;
  68                 }
  69         }
  70         return retval;
  71 }
  72
  73 static int table_hash_modify(struct sw_table *swt,
  74                 const struct sw_flow_key *key, uint16_t priority, int strict,
  75                 const struct ofp_action_header *actions, size_t actions_len)
  76 {
  77         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  78         unsigned int count = 0;
  79
  80         if (key->wildcards == 0) {
  81                 struct sw_flow **bucket = find_bucket(swt, key);
  82                 struct sw_flow *flow = *bucket;
  83                 if (flow && flow_matches_desc(&flow->key, key, strict)
  84                                 && (!strict || (flow->priority == priority))) {
  85                         flow_replace_acts(flow, actions, actions_len);
  86                         count = 1;
  87                 }
  88         } else {
  89                 unsigned int i;
  90
  91                 for (i = 0; i <= th->bucket_mask; i++) {
  92                         struct sw_flow **bucket = &th->buckets[i];
  93                         struct sw_flow *flow = *bucket;
  94                         if (flow && flow_matches_desc(&flow->key, key, strict)
  95                                         && (!strict || (flow->priority == priority))) {
  96                                 flow_replace_acts(flow, actions, actions_len);
  97                                 count++;
  98                         }
  99                 }
 100         }
 101         return count;
 102 }
 103
 104 /* Caller must update n_flows. */
 105 static int do_delete(struct sw_flow **bucket, struct sw_flow *flow)
 106 {
 107         rcu_assign_pointer(*bucket, NULL);
 108         flow_deferred_free(flow);
 109         return 1;
 110 }
 111
 112 /* Returns number of deleted flows.  We can ignore the priority
 113  * argument, since all exact-match entries are the same (highest)
 114  * priority. */
 115 static int table_hash_delete(struct sw_table *swt,
 116                                                          const struct sw_flow_key *key,
 117                                                          uint16_t priority, int strict)
 118 {
 119         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 120         unsigned int count = 0;
 121
 122         if (key->wildcards == 0) {
 123                 struct sw_flow **bucket = find_bucket(swt, key);
 124                 struct sw_flow *flow = *bucket;
 125                 if (flow && flow_keys_equal(&flow->key, key))
 126                         count = do_delete(bucket, flow);
 127         } else {
 128                 unsigned int i;
 129
 130                 for (i = 0; i <= th->bucket_mask; i++) {
 131                         struct sw_flow **bucket = &th->buckets[i];
 132                         struct sw_flow *flow = *bucket;
 133                         if (flow && flow_matches_desc(&flow->key, key, strict))
 134                                 count += do_delete(bucket, flow);
 135                 }
 136         }
 137         th->n_flows -= count;
 138         return count;
 139 }
 140
 141 static int table_hash_timeout(struct datapath *dp, struct sw_table *swt)
 142 {
 143         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 144         unsigned int i;
 145         int count = 0;
 146
 147         mutex_lock(&dp_mutex);
 148         for (i = 0; i <= th->bucket_mask; i++) {
 149                 struct sw_flow **bucket = &th->buckets[i];
 150                 struct sw_flow *flow = *bucket;
 151                 if (flow) {
 152                         int reason = flow_timeout(flow);
 153                         if (reason >= 0) {
 154                                 count += do_delete(bucket, flow);
 155                                 dp_send_flow_expired(dp, flow, reason);
 156                         }
 157                 }
 158         }
 159         th->n_flows -= count;
 160         mutex_unlock(&dp_mutex);
 161
 162         return count;
 163 }
 164
 165 static void table_hash_destroy(struct sw_table *swt)
 166 {
 167         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 168         unsigned int i;
 169         for (i = 0; i <= th->bucket_mask; i++)
 170         if (th->buckets[i])
 171                 flow_free(th->buckets[i]);
 172         kmem_free(th->buckets, (th->bucket_mask + 1) * sizeof *th->buckets);
 173         kfree(th);
 174 }
 175
 176 static int table_hash_iterate(struct sw_table *swt,
 177                               const struct sw_flow_key *key,
 178                               struct sw_table_position *position,
 179                               int (*callback)(struct sw_flow *, void *private),
 180                               void *private)
 181 {
 182         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 183
 184         if (position->private[0] > th->bucket_mask)
 185                 return 0;
 186
 187         if (key->wildcards == 0) {
 188                 struct sw_flow *flow;
 189                 int error;
 190
 191                 flow = table_hash_lookup(swt, key);
 192                 if (!flow)
 193                         return 0;
 194
 195                 error = callback(flow, private);
 196                 if (!error)
 197                         position->private[0] = -1;
 198                 return error;
 199         } else {
 200                 int i;
 201
 202                 for (i = position->private[0]; i <= th->bucket_mask; i++) {
 203                         struct sw_flow *flow = th->buckets[i];
 204                         if (flow && flow_matches_1wild(&flow->key, key)) {
 205                                 int error = callback(flow, private);
 206                                 if (error) {
 207                                         position->private[0] = i;
 208                                         return error;
 209                                 }
 210                         }
 211                 }
 212                 return 0;
 213         }
 214 }
 215 static void table_hash_stats(struct sw_table *swt,
 216                                  struct sw_table_stats *stats)
 217 {
 218         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 219         stats->name = "hash";
 220         stats->wildcards = 0;          /* No wildcards are supported. */
 221         stats->n_flows   = th->n_flows;
 222         stats->max_flows = th->bucket_mask + 1;
 223         stats->n_lookup  = swt->n_lookup;
 224         stats->n_matched = swt->n_matched;
 225 }
 226
 227 struct sw_table *table_hash_create(unsigned int polynomial,
 228                         unsigned int n_buckets)
 229 {
 230         struct sw_table_hash *th;
 231         struct sw_table *swt;
 232
 233         th = kzalloc(sizeof *th, GFP_KERNEL);
 234         if (th == NULL)
 235                 return NULL;
 236
 237         BUG_ON(n_buckets & (n_buckets - 1));
 238         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 239         if (th->buckets == NULL) {
 240                 printk("failed to allocate %u buckets\n", n_buckets);
 241                 kfree(th);
 242                 return NULL;
 243         }
 244         th->bucket_mask = n_buckets - 1;
 245
 246         swt = &th->swt;
 247         swt->lookup = table_hash_lookup;
 248         swt->insert = table_hash_insert;
 249         swt->delete = table_hash_delete;
 250         swt->timeout = table_hash_timeout;
 251         swt->destroy = table_hash_destroy;
 252         swt->iterate = table_hash_iterate;
 253         swt->stats = table_hash_stats;
 254
 255         crc32_init(&th->crc32, polynomial);
 256         th->n_flows = 0;
 257
 258         return swt;
 259 }
 260
 261 /* Double-hashing table. */
 262
 263 struct sw_table_hash2 {
 264         struct sw_table swt;
 265         struct sw_table *subtable[2];
 266 };
 267
 268 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 269                                                                                   const struct sw_flow_key *key)
 270 {
 271         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 272         int i;
 273
 274         for (i = 0; i < 2; i++) {
 275                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 276                 if (flow && flow_keys_equal(&flow->key, key))
 277                         return flow;
 278         }
 279         return NULL;
 280 }
 281
 282 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 283 {
 284         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 285
 286         if (table_hash_insert(t2->subtable[0], flow))
 287                 return 1;
 288         return table_hash_insert(t2->subtable[1], flow);
 289 }
 290
 291 static int table_hash2_modify(struct sw_table *swt,
 292                 const struct sw_flow_key *key, uint16_t priority, int strict,
 293                 const struct ofp_action_header *actions, size_t actions_len)
 294 {
 295         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 296         return (table_hash_modify(t2->subtable[0], key, priority, strict,
 297                                         actions, actions_len)
 298                         + table_hash_modify(t2->subtable[1], key, priority, strict,
 299                                         actions, actions_len));
 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_lookup  = swt->n_lookup;
 361         stats->n_matched = swt->n_matched;
 362 }
 363
 364 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 365                                                                         unsigned int poly1, unsigned int buckets1)
 366
 367 {
 368         struct sw_table_hash2 *t2;
 369         struct sw_table *swt;
 370
 371         t2 = kzalloc(sizeof *t2, GFP_KERNEL);
 372         if (t2 == NULL)
 373                 return NULL;
 374
 375         t2->subtable[0] = table_hash_create(poly0, buckets0);
 376         if (t2->subtable[0] == NULL)
 377                 goto out_free_t2;
 378
 379         t2->subtable[1] = table_hash_create(poly1, buckets1);
 380         if (t2->subtable[1] == NULL)
 381                 goto out_free_subtable0;
 382
 383         swt = &t2->swt;
 384         swt->lookup = table_hash2_lookup;
 385         swt->insert = table_hash2_insert;
 386         swt->modify = table_hash2_modify;
 387         swt->delete = table_hash2_delete;
 388         swt->timeout = table_hash2_timeout;
 389         swt->destroy = table_hash2_destroy;
 390         swt->iterate = table_hash2_iterate;
 391         swt->stats = table_hash2_stats;
 392
 393         return swt;
 394
 395 out_free_subtable0:
 396         table_hash_destroy(t2->subtable[0]);
 397 out_free_t2:
 398         kfree(t2);
 399         return NULL;
 400 }
 401
 402 /* From fs/xfs/linux-2.4/kmem.c. */
 403
 404 static void *
 405 kmem_alloc(size_t size)
 406 {
 407         void *ptr;
 408
 409 #ifdef KMALLOC_MAX_SIZE
 410         if (size > KMALLOC_MAX_SIZE)
 411                 return NULL;
 412 #endif
 413         ptr = kmalloc(size, GFP_KERNEL);
 414         if (!ptr) {
 415                 ptr = vmalloc(size);
 416                 if (ptr)
 417                         printk("openflow: used vmalloc for %lu bytes\n",
 418                                         (unsigned long)size);
 419         }
 420         return ptr;
 421 }
 422
 423 static void *
 424 kmem_zalloc(size_t size)
 425 {
 426         void *ptr = kmem_alloc(size);
 427         if (ptr)
 428                 memset(ptr, 0, size);
 429         return ptr;
 430 }
 431
 432 static void
 433 kmem_free(void *ptr, size_t size)
 434 {
 435         if (((unsigned long)ptr < VMALLOC_START) ||
 436                 ((unsigned long)ptr >= VMALLOC_END)) {
 437                 kfree(ptr);
 438         } else {
 439                 vfree(ptr);
 440         }
 441 }