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         spinlock_t lock;
  25         struct crc32 crc32;
  26         atomic_t n_flows;
  27         unsigned int bucket_mask; /* Number of buckets minus 1. */
  28         struct sw_flow **buckets;
  29 };
  30
  31 static struct sw_flow **find_bucket(struct sw_table *swt,
  32                                                                         const struct sw_flow_key *key)
  33 {
  34         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  35         unsigned int crc = crc32_calculate(&th->crc32, key, sizeof *key);
  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 && !memcmp(&flow->key, key, sizeof *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         unsigned long int flags;
  51         int retval;
  52
  53         if (flow->key.wildcards != 0)
  54                 return 0;
  55
  56         spin_lock_irqsave(&th->lock, flags);
  57         bucket = find_bucket(swt, &flow->key);
  58         if (*bucket == NULL) {
  59                 atomic_inc(&th->n_flows);
  60                 rcu_assign_pointer(*bucket, flow);
  61                 retval = 1;
  62         } else {
  63                 struct sw_flow *old_flow = *bucket;
  64                 if (!memcmp(&old_flow->key, &flow->key, sizeof flow->key)
  65                                         && flow_del(old_flow)) {
  66                         rcu_assign_pointer(*bucket, flow);
  67                         flow_deferred_free(old_flow);
  68                         retval = 1;
  69                 } else {
  70                         retval = 0;
  71                 }
  72         }
  73         spin_unlock_irqrestore(&th->lock, flags);
  74         return retval;
  75 }
  76
  77 /* Caller must update n_flows. */
  78 static int do_delete(struct sw_flow **bucket, struct sw_flow *flow)
  79 {
  80         if (flow_del(flow)) {
  81                 rcu_assign_pointer(*bucket, NULL);
  82                 flow_deferred_free(flow);
  83                 return 1;
  84         }
  85         return 0;
  86 }
  87
  88 /* Returns number of deleted flows. */
  89 static int table_hash_delete(struct sw_table *swt,
  90                                                          const struct sw_flow_key *key, int strict)
  91 {
  92         struct sw_table_hash *th = (struct sw_table_hash *) swt;
  93         unsigned int count = 0;
  94
  95         if (key->wildcards == 0) {
  96                 struct sw_flow **bucket = find_bucket(swt, key);
  97                 struct sw_flow *flow = *bucket;
  98                 if (flow && !memcmp(&flow->key, key, sizeof *key))
  99                         count = do_delete(bucket, flow);
 100         } else {
 101                 unsigned int i;
 102
 103                 for (i = 0; i <= th->bucket_mask; i++) {
 104                         struct sw_flow **bucket = &th->buckets[i];
 105                         struct sw_flow *flow = *bucket;
 106                         if (flow && flow_del_matches(&flow->key, key, strict))
 107                                 count += do_delete(bucket, flow);
 108                 }
 109         }
 110         if (count)
 111                 atomic_sub(count, &th->n_flows);
 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         for (i = 0; i <= th->bucket_mask; i++) {
 122                 struct sw_flow **bucket = &th->buckets[i];
 123                 struct sw_flow *flow = *bucket;
 124                 if (flow && flow_timeout(flow)) {
 125                         count += do_delete(bucket, flow);
 126                         if (dp->flags & OFPC_SEND_FLOW_EXP)
 127                                 dp_send_flow_expired(dp, flow);
 128                 }
 129         }
 130
 131         if (count)
 132                 atomic_sub(count, &th->n_flows);
 133         return count;
 134 }
 135
 136 static void table_hash_destroy(struct sw_table *swt)
 137 {
 138         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 139         unsigned int i;
 140         for (i = 0; i <= th->bucket_mask; i++)
 141         if (th->buckets[i])
 142                 flow_free(th->buckets[i]);
 143         kmem_free(th->buckets, (th->bucket_mask + 1) * sizeof *th->buckets);
 144         kfree(th);
 145 }
 146
 147 static int table_hash_iterate(struct sw_table *swt,
 148                               const struct sw_flow_key *key,
 149                               struct sw_table_position *position,
 150                               int (*callback)(struct sw_flow *, void *private),
 151                               void *private)
 152 {
 153         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 154
 155         if (position->private[0] > th->bucket_mask)
 156                 return 0;
 157
 158         if (key->wildcards == 0) {
 159                 struct sw_flow *flow = table_hash_lookup(swt, key);
 160                 position->private[0] = -1;
 161                 return flow ? callback(flow, private) : 0;
 162         } else {
 163                 int i;
 164
 165                 for (i = position->private[0]; i <= th->bucket_mask; i++) {
 166                         struct sw_flow *flow = th->buckets[i];
 167                         if (flow && flow_matches(key, &flow->key)) {
 168                                 int error = callback(flow, private);
 169                                 if (error) {
 170                                         position->private[0] = i + 1;
 171                                         return error;
 172                                 }
 173                         }
 174                 }
 175                 return 0;
 176         }
 177 }
 178 static void table_hash_stats(struct sw_table *swt,
 179                                  struct sw_table_stats *stats)
 180 {
 181         struct sw_table_hash *th = (struct sw_table_hash *) swt;
 182         stats->name = "hash";
 183         stats->n_flows = atomic_read(&th->n_flows);
 184         stats->max_flows = th->bucket_mask + 1;
 185 }
 186
 187 struct sw_table *table_hash_create(unsigned int polynomial,
 188                         unsigned int n_buckets)
 189 {
 190         struct sw_table_hash *th;
 191         struct sw_table *swt;
 192
 193         th = kmalloc(sizeof *th, GFP_KERNEL);
 194         if (th == NULL)
 195                 return NULL;
 196
 197         BUG_ON(n_buckets & (n_buckets - 1));
 198         th->buckets = kmem_zalloc(n_buckets * sizeof *th->buckets);
 199         if (th->buckets == NULL) {
 200                 printk("failed to allocate %u buckets\n", n_buckets);
 201                 kfree(th);
 202                 return NULL;
 203         }
 204         th->bucket_mask = n_buckets - 1;
 205
 206         swt = &th->swt;
 207         swt->lookup = table_hash_lookup;
 208         swt->insert = table_hash_insert;
 209         swt->delete = table_hash_delete;
 210         swt->timeout = table_hash_timeout;
 211         swt->destroy = table_hash_destroy;
 212         swt->iterate = table_hash_iterate;
 213         swt->stats = table_hash_stats;
 214
 215         spin_lock_init(&th->lock);
 216         crc32_init(&th->crc32, polynomial);
 217         atomic_set(&th->n_flows, 0);
 218
 219         return swt;
 220 }
 221
 222 /* Double-hashing table. */
 223
 224 struct sw_table_hash2 {
 225         struct sw_table swt;
 226         struct sw_table *subtable[2];
 227 };
 228
 229 static struct sw_flow *table_hash2_lookup(struct sw_table *swt,
 230                                                                                   const struct sw_flow_key *key)
 231 {
 232         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 233         int i;
 234
 235         for (i = 0; i < 2; i++) {
 236                 struct sw_flow *flow = *find_bucket(t2->subtable[i], key);
 237                 if (flow && !memcmp(&flow->key, key, sizeof *key))
 238                         return flow;
 239         }
 240         return NULL;
 241 }
 242
 243 static int table_hash2_insert(struct sw_table *swt, struct sw_flow *flow)
 244 {
 245         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 246
 247         if (table_hash_insert(t2->subtable[0], flow))
 248                 return 1;
 249         return table_hash_insert(t2->subtable[1], flow);
 250 }
 251
 252 static int table_hash2_delete(struct sw_table *swt,
 253                                                           const struct sw_flow_key *key, int strict)
 254 {
 255         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 256         return (table_hash_delete(t2->subtable[0], key, strict)
 257                         + table_hash_delete(t2->subtable[1], key, strict));
 258 }
 259
 260 static int table_hash2_timeout(struct datapath *dp, struct sw_table *swt)
 261 {
 262         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 263         return (table_hash_timeout(dp, t2->subtable[0])
 264                         + table_hash_timeout(dp, t2->subtable[1]));
 265 }
 266
 267 static void table_hash2_destroy(struct sw_table *swt)
 268 {
 269         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 270         table_hash_destroy(t2->subtable[0]);
 271         table_hash_destroy(t2->subtable[1]);
 272         kfree(t2);
 273 }
 274
 275 static int table_hash2_iterate(struct sw_table *swt,
 276                                const struct sw_flow_key *key,
 277                                struct sw_table_position *position,
 278                                int (*callback)(struct sw_flow *, void *),
 279                                void *private)
 280 {
 281         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 282         int i;
 283
 284         for (i = position->private[1]; i < 2; i++) {
 285                 int error = table_hash_iterate(t2->subtable[i], key, position,
 286                                                callback, private);
 287                 if (error) {
 288                         return error;
 289                 }
 290                 position->private[0] = 0;
 291                 position->private[1]++;
 292         }
 293         return 0;
 294 }
 295
 296 static void table_hash2_stats(struct sw_table *swt,
 297                                  struct sw_table_stats *stats)
 298 {
 299         struct sw_table_hash2 *t2 = (struct sw_table_hash2 *) swt;
 300         struct sw_table_stats substats[2];
 301         int i;
 302
 303         for (i = 0; i < 2; i++)
 304                 table_hash_stats(t2->subtable[i], &substats[i]);
 305         stats->name = "hash2";
 306         stats->n_flows = substats[0].n_flows + substats[1].n_flows;
 307         stats->max_flows = substats[0].max_flows + substats[1].max_flows;
 308 }
 309
 310 struct sw_table *table_hash2_create(unsigned int poly0, unsigned int buckets0,
 311                                                                         unsigned int poly1, unsigned int buckets1)
 312
 313 {
 314         struct sw_table_hash2 *t2;
 315         struct sw_table *swt;
 316
 317         t2 = kmalloc(sizeof *t2, GFP_KERNEL);
 318         if (t2 == NULL)
 319                 return NULL;
 320
 321         t2->subtable[0] = table_hash_create(poly0, buckets0);
 322         if (t2->subtable[0] == NULL)
 323                 goto out_free_t2;
 324
 325         t2->subtable[1] = table_hash_create(poly1, buckets1);
 326         if (t2->subtable[1] == NULL)
 327                 goto out_free_subtable0;
 328
 329         swt = &t2->swt;
 330         swt->lookup = table_hash2_lookup;
 331         swt->insert = table_hash2_insert;
 332         swt->delete = table_hash2_delete;
 333         swt->timeout = table_hash2_timeout;
 334         swt->destroy = table_hash2_destroy;
 335         swt->iterate = table_hash2_iterate;
 336         swt->stats = table_hash2_stats;
 337
 338         return swt;
 339
 340 out_free_subtable0:
 341         table_hash_destroy(t2->subtable[0]);
 342 out_free_t2:
 343         kfree(t2);
 344         return NULL;
 345 }
 346
 347 /* From fs/xfs/linux-2.4/kmem.c. */
 348
 349 static void *
 350 kmem_alloc(size_t size)
 351 {
 352         void *ptr;
 353
 354 #ifdef KMALLOC_MAX_SIZE
 355         if (size > KMALLOC_MAX_SIZE)
 356                 return NULL;
 357 #endif
 358         ptr = kmalloc(size, GFP_KERNEL);
 359         if (!ptr) {
 360                 ptr = vmalloc(size);
 361                 if (ptr)
 362                         printk("openflow: used vmalloc for %lu bytes\n",
 363                                         (unsigned long)size);
 364         }
 365         return ptr;
 366 }
 367
 368 static void *
 369 kmem_zalloc(size_t size)
 370 {
 371         void *ptr = kmem_alloc(size);
 372         if (ptr)
 373                 memset(ptr, 0, size);
 374         return ptr;
 375 }
 376
 377 static void
 378 kmem_free(void *ptr, size_t size)
 379 {
 380         if (((unsigned long)ptr < VMALLOC_START) ||
 381                 ((unsigned long)ptr >= VMALLOC_END)) {
 382                 kfree(ptr);
 383         } else {
 384                 vfree(ptr);
 385         }
 386 }