datapath/table-mac.c

   1 /*
   2  * Distributed under the terms of the GNU GPL version 2.
   3  * Copyright (c) 2007 The Board of Trustees of The Leland Stanford Junior Univer
   4 sity
   5  */
   6
   7 #include "table.h"
   8 #include "crc32.h"
   9 #include "flow.h"
  10 #include "openflow.h"
  11 #include "datapath.h"
  12
  13 #include <linux/slab.h>
  14
  15 struct sw_table_mac {
  16         struct sw_table swt;
  17         spinlock_t lock;
  18         struct crc32 crc32;
  19         atomic_t n_flows;
  20         unsigned int max_flows;
  21         unsigned int bucket_mask; /* Number of buckets minus 1. */
  22         struct hlist_head *buckets;
  23 };
  24
  25 static struct hlist_head *find_bucket(struct sw_table *swt,
  26                                                                          const struct sw_flow_key *key)
  27 {
  28         struct sw_table_mac *tm = (struct sw_table_mac *) swt;
  29         unsigned int crc = crc32_calculate(&tm->crc32, key, sizeof *key);
  30         return &tm->buckets[crc & tm->bucket_mask];
  31 }
  32
  33 static struct sw_flow *table_mac_lookup(struct sw_table *swt,
  34                                                                                 const struct sw_flow_key *key)
  35 {
  36         struct hlist_head *bucket = find_bucket(swt, key);
  37         struct hlist_node *pos;
  38         struct sw_flow *flow;
  39         hlist_for_each_entry_rcu (flow, pos, bucket, u.hnode)
  40                 if (!memcmp(key->dl_src, flow->key.dl_src, 6))
  41                         return flow;
  42         return NULL;
  43 }
  44
  45 static int table_mac_insert(struct sw_table *swt, struct sw_flow *flow)
  46 {
  47         struct sw_table_mac *tm = (struct sw_table_mac *) swt;
  48         struct hlist_head *bucket;
  49         struct hlist_node *pos;
  50         unsigned long int flags;
  51         struct sw_flow *f;
  52
  53         /* MAC table only handles flows that match on Ethernet
  54            source address and wildcard everything else. */
  55         if (likely(flow->key.wildcards != (OFPFW_ALL & ~OFPFW_DL_SRC)))
  56                         return 0;
  57         bucket = find_bucket(swt, &flow->key);
  58
  59         spin_lock_irqsave(&tm->lock, flags);
  60         hlist_for_each_entry_rcu (f, pos, bucket, u.hnode) {
  61                 if (!memcmp(f->key.dl_src, flow->key.dl_src, 6)
  62                                         && flow_del(f)) {
  63                         hlist_replace_rcu(&f->u.hnode, &flow->u.hnode);
  64                         spin_unlock_irqrestore(&tm->lock, flags);
  65                         flow_deferred_free(f);
  66                         return 1;
  67                 }
  68         }
  69
  70         /* Table overflow? */
  71         if (atomic_read(&tm->n_flows) >= tm->max_flows) {
  72                 spin_unlock_irqrestore(&tm->lock, flags);
  73                 return 0;
  74         }
  75         atomic_inc(&tm->n_flows);
  76
  77         hlist_add_head_rcu(&flow->u.hnode, bucket);
  78         spin_unlock_irqrestore(&tm->lock, flags);
  79         return 1;
  80 }
  81
  82 static int do_delete(struct sw_table *swt, struct sw_flow *flow)
  83 {
  84         if (flow_del(flow)) {
  85                 hlist_del_rcu(&flow->u.hnode);
  86                 flow_deferred_free(flow);
  87                 return 1;
  88         }
  89         return 0;
  90 }
  91
  92 /* Returns number of deleted flows. */
  93 static int table_mac_delete(struct sw_table *swt,
  94                         const struct sw_flow_key *key, int strict)
  95 {
  96                 struct sw_table_mac *tm = (struct sw_table_mac *) swt;
  97
  98         if (key->wildcards == (OFPFW_ALL & ~OFPFW_DL_SRC)) {
  99                 struct sw_flow *flow = table_mac_lookup(swt, key);
 100                 if (flow && do_delete(swt, flow)) {
 101                         atomic_dec(&tm->n_flows);
 102                         return 1;
 103                 }
 104                 return 0;
 105         } else {
 106                 unsigned int i;
 107                 int count = 0;
 108                 for (i = 0; i <= tm->bucket_mask; i++) {
 109                         struct hlist_head *bucket = &tm->buckets[i];
 110                         struct hlist_node *pos;
 111                         struct sw_flow *flow;
 112                         hlist_for_each_entry_rcu (flow, pos, bucket, u.hnode)
 113                                 if (flow_del_matches(&flow->key, key, strict))
 114                                         count += do_delete(swt, flow);
 115                 }
 116                 if (count)
 117                         atomic_sub(count, &tm->n_flows);
 118                 return count;
 119         }
 120 }
 121
 122 static int table_mac_timeout(struct datapath *dp, struct sw_table *swt)
 123 {
 124         struct sw_table_mac *tm = (struct sw_table_mac *) swt;
 125         unsigned int i;
 126         int count = 0;
 127
 128         for (i = 0; i <= tm->bucket_mask; i++) {
 129                 struct hlist_head *bucket = &tm->buckets[i];
 130                 struct hlist_node *pos;
 131                 struct sw_flow *flow;
 132                 hlist_for_each_entry_rcu (flow, pos, bucket, u.hnode) {
 133                         if (flow_timeout(flow)) {
 134                                 count += do_delete(swt, flow);
 135                                 if (dp->hello_flags & OFP_CHELLO_SEND_FLOW_EXP)
 136                                         dp_send_flow_expired(dp, flow);
 137                         }
 138                 }
 139         }
 140         if (count)
 141                 atomic_sub(count, &tm->n_flows);
 142         return count;
 143 }
 144
 145 static void table_mac_destroy(struct sw_table *swt)
 146 {
 147         struct sw_table_mac *tm = (struct sw_table_mac *) swt;
 148         unsigned int i;
 149         for (i = 0; i <= tm->bucket_mask; i++) {
 150                 struct hlist_head *hlist = &tm->buckets[i];
 151                 while (!hlist_empty(hlist)) {
 152                         struct sw_flow *flow = hlist_entry(hlist->first,
 153                                            struct sw_flow, u.hnode);
 154                         hlist_del(&flow->u.hnode);
 155                         flow_free(flow);
 156                         }
 157         }
 158         kfree(tm->buckets);
 159         kfree(tm);
 160 }
 161
 162 struct swt_iterator_mac {
 163         struct sw_table_mac *tm;
 164         unsigned int bucket_i;
 165 };
 166
 167 static struct sw_flow *next_head_flow(struct swt_iterator_mac *im)
 168 {
 169         for (; im->bucket_i <= im->tm->bucket_mask; im->bucket_i++) {
 170                 struct hlist_node *first = im->tm->buckets[im->bucket_i].first;
 171                 if (first != NULL) {
 172                         struct sw_flow *f = hlist_entry(first,
 173                                                         struct sw_flow,
 174                                                         u.hnode);
 175                         return f;
 176                 }
 177         }
 178         return NULL;
 179 }
 180
 181 static int table_mac_iterator(struct sw_table *swt,
 182                                   struct swt_iterator *swt_iter)
 183 {
 184         struct swt_iterator_mac *im;
 185
 186         swt_iter->private = im = kmalloc(sizeof *im, GFP_KERNEL);
 187         if (im == NULL)
 188                 return 0;
 189
 190         im->tm = (struct sw_table_mac *) swt;
 191
 192         if (atomic_read(&im->tm->n_flows) == 0)
 193                 swt_iter->flow = NULL;
 194         else {
 195                 im->bucket_i = 0;
 196                 swt_iter->flow = next_head_flow(im);
 197         }
 198
 199         return 1;
 200 }
 201
 202 static void table_mac_next(struct swt_iterator *swt_iter)
 203 {
 204         struct swt_iterator_mac *im;
 205         struct hlist_node *next;
 206
 207         if (swt_iter->flow == NULL)
 208                 return;
 209
 210         im = (struct swt_iterator_mac *) swt_iter->private;
 211
 212         next = swt_iter->flow->u.hnode.next;
 213         if (next != NULL) {
 214                 swt_iter->flow = hlist_entry(next, struct sw_flow, u.hnode);
 215         } else {
 216                 im->bucket_i++;
 217                 swt_iter->flow = next_head_flow(im);
 218         }
 219 }
 220
 221 static void table_mac_iterator_destroy(struct swt_iterator *swt_iter)
 222 {
 223         kfree(swt_iter->private);
 224 }
 225
 226 static void table_mac_stats(struct sw_table *swt, struct sw_table_stats *stats)
 227 {
 228         struct sw_table_mac *tm = (struct sw_table_mac *) swt;
 229         stats->name = "mac";
 230         stats->n_flows = atomic_read(&tm->n_flows);
 231         stats->max_flows = tm->max_flows;
 232 }
 233
 234 struct sw_table *table_mac_create(unsigned int n_buckets,
 235                                                                   unsigned int max_flows)
 236 {
 237         struct sw_table_mac *tm;
 238         struct sw_table *swt;
 239
 240         tm = kzalloc(sizeof *tm, GFP_KERNEL);
 241         if (tm == NULL)
 242                 return NULL;
 243
 244         BUG_ON(n_buckets & (n_buckets - 1));
 245
 246         tm->buckets = kzalloc(n_buckets * sizeof *tm->buckets, GFP_KERNEL);
 247         if (tm->buckets == NULL) {
 248                 printk("failed to allocate %u buckets\n", n_buckets);
 249                 kfree(tm);
 250                 return NULL;
 251         }
 252         tm->bucket_mask = n_buckets - 1;
 253
 254         swt = &tm->swt;
 255         swt->lookup = table_mac_lookup;
 256         swt->insert = table_mac_insert;
 257         swt->delete = table_mac_delete;
 258         swt->timeout = table_mac_timeout;
 259         swt->destroy = table_mac_destroy;
 260         swt->stats = table_mac_stats;
 261
 262         swt->iterator = table_mac_iterator;
 263         swt->iterator_next = table_mac_next;
 264         swt->iterator_destroy = table_mac_iterator_destroy;
 265
 266         crc32_init(&tm->crc32, 0x04C11DB7); /* Ethernet CRC. */
 267         atomic_set(&tm->n_flows, 0);
 268         tm->max_flows = max_flows;
 269         spin_lock_init(&tm->lock);
 270
 271         return swt;
 272 }