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 datapath *dp, struct sw_flow **bucket,
 106                         struct sw_flow *flow, enum nx_flow_end_reason reason)
 107 {
 108         dp_send_flow_end(dp, flow, reason);
 109         rcu_assign_pointer(*bucket, NULL);
 110         flow_deferred_free(flow);
 111         return 1;
 112 }
 113
 114 /* Returns number of deleted flows.  We can ignore the priority
 115  * argument, since all exact-match entries are the same (highest)
 116  * priority. */
 117 static int table_hash_delete(struct datapath *dp, struct sw_table *swt,
 118                                         const struct sw_flow_key *key,  uint16_t out_port,
 119                                         uint16_t priority, int strict)
 120 {
 121         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 122         unsigned int count = 0;
 123
 124         if (key->wildcards == 0) {
 125                 struct sw_flow **bucket = find_bucket(swt, key);
 126                 struct sw_flow *flow = *bucket;
 127                 if (flow && flow_keys_equal(&flow->key, key)
 128                                 && flow_has_out_port(flow, out_port))
 129                         count = do_delete(dp, bucket, flow, NXFER_DELETE);
 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_matches_desc(&flow->key, key, strict)
 137                                         && flow_has_out_port(flow, out_port))
 138                                 count = do_delete(dp, bucket, flow, NXFER_DELETE);
 139                 }
 140         }
 141         th->n_flows -= count;
 142         return count;
 143 }
 144
 145 static int table_hash_timeout(struct datapath *dp, struct sw_table *swt)
 146 {
 147         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 148         unsigned int i;
 149         int count = 0;
 150
 151         mutex_lock(&dp_mutex);
 152         for (i = 0; i <= th->bucket_mask; i++) {
 153                 struct sw_flow **bucket = &th->buckets[i];
 154                 struct sw_flow *flow = *bucket;
 155                 if (flow) {
 156                         int reason = flow_timeout(flow);
 157                         if (reason >= 0) {
 158                                 count += do_delete(dp, bucket, 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, uint16_t out_port,
 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 || !flow_has_out_port(flow, out_port))
 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                                         && flow_has_out_port(flow, out_port)) {
 209                                 int error = callback(flow, private);
 210                                 if (error) {
 211                                         position->private[0] = i;
 212                                         return error;
 213                                 }
 214                         }
 215                 }
 216                 return 0;
 217         }
 218 }
 219 static void table_hash_stats(struct sw_table *swt,
 220                                  struct sw_table_stats *stats)
 221 {
 222         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 223         stats->name = "hash";
 224         stats->wildcards = 0;          /* No wildcards are supported. */
 225         stats->n_flows   = th->n_flows;
 226         stats->max_flows = th->bucket_mask + 1;
 227         stats->n_lookup  = swt->n_lookup;
 228         stats->n_matched = swt->n_matched;
 229 }
 230
 231 struct sw_table *table_hash_create(unsigned int polynomial,
 232                         unsigned int n_buckets)
 233 {
 234         struct sw_table_hash *th;
 235         struct sw_table *swt;
 236
 237         th = kzalloc(sizeof *th, GFP_KERNEL);
 238         if (th == NULL)
 239                 return NULL;
 240
 241         BUG_ON(n_buckets & (n_buckets - 1));
 242         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 243         if (th->buckets == NULL) {
 244                 printk("failed to allocate %u buckets\n", n_buckets);
 245                 kfree(th);
 246                 return NULL;
 247         }
 248         th->bucket_mask = n_buckets - 1;
 249
 250         swt = &th->swt;
 251         swt->lookup = table_hash_lookup;
 252         swt->insert = table_hash_insert;
 253         swt->delete = table_hash_delete;
 254         swt->timeout = table_hash_timeout;
 255         swt->destroy = table_hash_destroy;
 256         swt->iterate = table_hash_iterate;
 257         swt->stats = table_hash_stats;
 258
 259         crc32_init(&th->crc32, polynomial);
 260         th->n_flows = 0;
 261
 262         return swt;
 263 }
 264
 265 /* Double-hashing table. */
 266
 267 struct sw_table_hash2 {
 268         struct sw_table swt;
 269         struct sw_table *subtable[2];
 270 };
 271
 272 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 273                                                                                   const struct sw_flow_key *key)
 274 {
 275         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 276         int i;
 277
 278         for (i = 0; i < 2; i++) {
 279                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 280                 if (flow && flow_keys_equal(&flow->key, key))
 281                         return flow;
 282         }
 283         return NULL;
 284 }
 285
 286 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 287 {
 288         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 289
 290         if (table_hash_insert(t2->subtable[0], flow))
 291                 return 1;
 292         return table_hash_insert(t2->subtable[1], flow);
 293 }
 294
 295 static int table_hash2_modify(struct sw_table *swt,
 296                 const struct sw_flow_key *key, uint16_t priority, int strict,
 297                 const struct ofp_action_header *actions, size_t actions_len)
 298 {
 299         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 300         return (table_hash_modify(t2->subtable[0], key, priority, strict,
 301                                         actions, actions_len)
 302                         + table_hash_modify(t2->subtable[1], key, priority, strict,
 303                                         actions, actions_len));
 304 }
 305
 306 static int table_hash2_delete(struct datapath *dp, struct sw_table *swt,
 307                                                           const struct sw_flow_key *key,
 308                                                           uint16_t out_port,
 309                                                           uint16_t priority, int strict)
 310 {
 311         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 312         return (table_hash_delete(dp, t2->subtable[0], key, out_port,
 313                                 priority, strict)
 314                         + table_hash_delete(dp, t2->subtable[1], key, out_port,
 315                                 priority, strict));
 316 }
 317
 318 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 319 {
 320         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 321         return (table_hash_timeout(dp, t2->subtable[0])
 322                         + table_hash_timeout(dp, t2->subtable[1]));
 323 }
 324
 325 static void table_hash2_destroy(struct sw_table *swt)
 326 {
 327         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 328         table_hash_destroy(t2->subtable[0]);
 329         table_hash_destroy(t2->subtable[1]);
 330         kfree(t2);
 331 }
 332
 333 static int table_hash2_iterate(struct sw_table *swt,
 334                                const struct sw_flow_key *key, uint16_t out_port,
 335                                struct sw_table_position *position,
 336                                int (*callback)(struct sw_flow *, void *),
 337                                void *private)
 338 {
 339         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 340         int i;
 341
 342         for (i = position->private[1]; i < 2; i++) {
 343                 int error = table_hash_iterate(t2->subtable[i], key, out_port,
 344                                 position, callback, private);
 345                 if (error) {
 346                         return error;
 347                 }
 348                 position->private[0] = 0;
 349                 position->private[1]++;
 350         }
 351         return 0;
 352 }
 353
 354 static void table_hash2_stats(struct sw_table *swt,
 355                                  struct sw_table_stats *stats)
 356 {
 357         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 358         struct sw_table_stats substats[2];
 359         int i;
 360
 361         for (i = 0; i < 2; i++)
 362                 table_hash_stats(t2->subtable[i], &substats[i]);
 363         stats->name = "hash2";
 364         stats->wildcards = 0;          /* No wildcards are supported. */
 365         stats->n_flows   = substats[0].n_flows + substats[1].n_flows;
 366         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 367         stats->n_lookup  = swt->n_lookup;
 368         stats->n_matched = swt->n_matched;
 369 }
 370
 371 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 372                                                                         unsigned int poly1, unsigned int buckets1)
 373
 374 {
 375         struct sw_table_hash2 *t2;
 376         struct sw_table *swt;
 377
 378         t2 = kzalloc(sizeof *t2, GFP_KERNEL);
 379         if (t2 == NULL)
 380                 return NULL;
 381
 382         t2->subtable[0] = table_hash_create(poly0, buckets0);
 383         if (t2->subtable[0] == NULL)
 384                 goto out_free_t2;
 385
 386         t2->subtable[1] = table_hash_create(poly1, buckets1);
 387         if (t2->subtable[1] == NULL)
 388                 goto out_free_subtable0;
 389
 390         swt = &t2->swt;
 391         swt->lookup = table_hash2_lookup;
 392         swt->insert = table_hash2_insert;
 393         swt->modify = table_hash2_modify;
 394         swt->delete = table_hash2_delete;
 395         swt->timeout = table_hash2_timeout;
 396         swt->destroy = table_hash2_destroy;
 397         swt->iterate = table_hash2_iterate;
 398         swt->stats = table_hash2_stats;
 399
 400         return swt;
 401
 402 out_free_subtable0:
 403         table_hash_destroy(t2->subtable[0]);
 404 out_free_t2:
 405         kfree(t2);
 406         return NULL;
 407 }
 408
 409 /* From fs/xfs/linux-2.4/kmem.c. */
 410
 411 static void *
 412 kmem_alloc(size_t size)
 413 {
 414         void *ptr;
 415
 416 #ifdef KMALLOC_MAX_SIZE
 417         if (size > KMALLOC_MAX_SIZE)
 418                 return NULL;
 419 #endif
 420         ptr = kmalloc(size, GFP_KERNEL);
 421         if (!ptr) {
 422                 ptr = vmalloc(size);
 423                 if (ptr)
 424                         printk("openflow: used vmalloc for %lu bytes\n",
 425                                         (unsigned long)size);
 426         }
 427         return ptr;
 428 }
 429
 430 static void *
 431 kmem_zalloc(size_t size)
 432 {
 433         void *ptr = kmem_alloc(size);
 434         if (ptr)
 435                 memset(ptr, 0, size);
 436         return ptr;
 437 }
 438
 439 static void
 440 kmem_free(void *ptr, size_t size)
 441 {
 442         if (((unsigned long)ptr < VMALLOC_START) ||
 443                 ((unsigned long)ptr >= VMALLOC_END)) {
 444                 kfree(ptr);
 445         } else {
 446                 vfree(ptr);
 447         }
 448 }