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