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 *actions, int n_actions)
  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, n_actions);
  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, n_actions);
  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_matched = swt->n_matched;
 224 }
 225
 226 struct sw_table *table_hash_create(unsigned int polynomial,
 227                         unsigned int n_buckets)
 228 {
 229         struct sw_table_hash *th;
 230         struct sw_table *swt;
 231
 232         th = kzalloc(sizeof *th, GFP_KERNEL);
 233         if (th == NULL)
 234                 return NULL;
 235
 236         BUG_ON(n_buckets & (n_buckets - 1));
 237         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 238         if (th->buckets == NULL) {
 239                 printk("failed to allocate %u buckets\n", n_buckets);
 240                 kfree(th);
 241                 return NULL;
 242         }
 243         th->bucket_mask = n_buckets - 1;
 244
 245         swt = &th->swt;
 246         swt->lookup = table_hash_lookup;
 247         swt->insert = table_hash_insert;
 248         swt->delete = table_hash_delete;
 249         swt->timeout = table_hash_timeout;
 250         swt->destroy = table_hash_destroy;
 251         swt->iterate = table_hash_iterate;
 252         swt->stats = table_hash_stats;
 253
 254         crc32_init(&th->crc32, polynomial);
 255         th->n_flows = 0;
 256
 257         return swt;
 258 }
 259
 260 /* Double-hashing table. */
 261
 262 struct sw_table_hash2 {
 263         struct sw_table swt;
 264         struct sw_table *subtable[2];
 265 };
 266
 267 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 268                                                                                   const struct sw_flow_key *key)
 269 {
 270         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 271         int i;
 272
 273         for (i = 0; i < 2; i++) {
 274                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 275                 if (flow && flow_keys_equal(&flow->key, key))
 276                         return flow;
 277         }
 278         return NULL;
 279 }
 280
 281 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 282 {
 283         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 284
 285         if (table_hash_insert(t2->subtable[0], flow))
 286                 return 1;
 287         return table_hash_insert(t2->subtable[1], flow);
 288 }
 289
 290 static int table_hash2_modify(struct sw_table *swt,
 291                 const struct sw_flow_key *key, uint16_t priority, int strict,
 292                 const struct ofp_action *actions, int n_actions)
 293 {
 294         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 295         return (table_hash_modify(t2->subtable[0], key, priority, strict,
 296                                         actions, n_actions)
 297                         + table_hash_modify(t2->subtable[1], key, priority, strict,
 298                                         actions, n_actions));
 299 }
 300
 301 static int table_hash2_delete(struct sw_table *swt,
 302                                                           const struct sw_flow_key *key,
 303                                                           uint16_t priority, int strict)
 304 {
 305         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 306         return (table_hash_delete(t2->subtable[0], key, priority, strict)
 307                         + table_hash_delete(t2->subtable[1], key, priority, strict));
 308 }
 309
 310 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 311 {
 312         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 313         return (table_hash_timeout(dp, t2->subtable[0])
 314                         + table_hash_timeout(dp, t2->subtable[1]));
 315 }
 316
 317 static void table_hash2_destroy(struct sw_table *swt)
 318 {
 319         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 320         table_hash_destroy(t2->subtable[0]);
 321         table_hash_destroy(t2->subtable[1]);
 322         kfree(t2);
 323 }
 324
 325 static int table_hash2_iterate(struct sw_table *swt,
 326                                const struct sw_flow_key *key,
 327                                struct sw_table_position *position,
 328                                int (*callback)(struct sw_flow *, void *),
 329                                void *private)
 330 {
 331         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 332         int i;
 333
 334         for (i = position->private[1]; i < 2; i++) {
 335                 int error = table_hash_iterate(t2->subtable[i], key, position,
 336                                                callback, private);
 337                 if (error) {
 338                         return error;
 339                 }
 340                 position->private[0] = 0;
 341                 position->private[1]++;
 342         }
 343         return 0;
 344 }
 345
 346 static void table_hash2_stats(struct sw_table *swt,
 347                                  struct sw_table_stats *stats)
 348 {
 349         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 350         struct sw_table_stats substats[2];
 351         int i;
 352
 353         for (i = 0; i < 2; i++)
 354                 table_hash_stats(t2->subtable[i], &substats[i]);
 355         stats->name = "hash2";
 356         stats->wildcards = 0;          /* No wildcards are supported. */
 357         stats->n_flows   = substats[0].n_flows + substats[1].n_flows;
 358         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 359         stats->n_matched = swt->n_matched;
 360 }
 361
 362 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 363                                                                         unsigned int poly1, unsigned int buckets1)
 364
 365 {
 366         struct sw_table_hash2 *t2;
 367         struct sw_table *swt;
 368
 369         t2 = kzalloc(sizeof *t2, GFP_KERNEL);
 370         if (t2 == NULL)
 371                 return NULL;
 372
 373         t2->subtable[0] = table_hash_create(poly0, buckets0);
 374         if (t2->subtable[0] == NULL)
 375                 goto out_free_t2;
 376
 377         t2->subtable[1] = table_hash_create(poly1, buckets1);
 378         if (t2->subtable[1] == NULL)
 379                 goto out_free_subtable0;
 380
 381         swt = &t2->swt;
 382         swt->lookup = table_hash2_lookup;
 383         swt->insert = table_hash2_insert;
 384         swt->modify = table_hash2_modify;
 385         swt->delete = table_hash2_delete;
 386         swt->timeout = table_hash2_timeout;
 387         swt->destroy = table_hash2_destroy;
 388         swt->iterate = table_hash2_iterate;
 389         swt->stats = table_hash2_stats;
 390
 391         return swt;
 392
 393 out_free_subtable0:
 394         table_hash_destroy(t2->subtable[0]);
 395 out_free_t2:
 396         kfree(t2);
 397         return NULL;
 398 }
 399
 400 /* From fs/xfs/linux-2.4/kmem.c. */
 401
 402 static void *
 403 kmem_alloc(size_t size)
 404 {
 405         void *ptr;
 406
 407 #ifdef KMALLOC_MAX_SIZE
 408         if (size > KMALLOC_MAX_SIZE)
 409                 return NULL;
 410 #endif
 411         ptr = kmalloc(size, GFP_KERNEL);
 412         if (!ptr) {
 413                 ptr = vmalloc(size);
 414                 if (ptr)
 415                         printk("openflow: used vmalloc for %lu bytes\n",
 416                                         (unsigned long)size);
 417         }
 418         return ptr;
 419 }
 420
 421 static void *
 422 kmem_zalloc(size_t size)
 423 {
 424         void *ptr = kmem_alloc(size);
 425         if (ptr)
 426                 memset(ptr, 0, size);
 427         return ptr;
 428 }
 429
 430 static void
 431 kmem_free(void *ptr, size_t size)
 432 {
 433         if (((unsigned long)ptr < VMALLOC_START) ||
 434                 ((unsigned long)ptr >= VMALLOC_END)) {
 435                 kfree(ptr);
 436         } else {
 437                 vfree(ptr);
 438         }
 439 }