datapath/table-linear.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 "flow.h"
   9 #include "datapath.h"
  10
  11 #include <linux/rcupdate.h>
  12 #include <linux/slab.h>
  13 #include <linux/list.h>
  14
  15 struct sw_table_linear {
  16         struct sw_table swt;
  17
  18         spinlock_t lock;
  19         unsigned int max_flows;
  20         atomic_t n_flows;
  21         struct list_head flows;
  22 };
  23
  24 static struct sw_flow *table_linear_lookup(struct sw_table *swt,
  25                                          const struct sw_flow_key *key)
  26 {
  27         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
  28         struct sw_flow *flow;
  29         list_for_each_entry_rcu (flow, &tl->flows, u.node) {
  30                 if (flow_matches(&flow->key, key))
  31                         return flow;
  32         }
  33         return NULL;
  34 }
  35
  36 static int table_linear_insert(struct sw_table *swt, struct sw_flow *flow)
  37 {
  38         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
  39         unsigned long int flags;
  40         struct sw_flow *f;
  41
  42         /* Replace flows that match exactly. */
  43         spin_lock_irqsave(&tl->lock, flags);
  44         list_for_each_entry_rcu (f, &tl->flows, u.node) {
  45                 if (f->key.wildcards == flow->key.wildcards
  46                                 && flow_matches(&f->key, &flow->key)
  47                                 && flow_del(f)) {
  48                         list_replace_rcu(&f->u.node, &flow->u.node);
  49                         spin_unlock_irqrestore(&tl->lock, flags);
  50                         flow_deferred_free(f);
  51                         return 1;
  52                 }
  53         }
  54
  55         /* Table overflow? */
  56         if (atomic_read(&tl->n_flows) >= tl->max_flows) {
  57                 spin_unlock_irqrestore(&tl->lock, flags);
  58                 return 0;
  59         }
  60         atomic_inc(&tl->n_flows);
  61
  62         /* FIXME: need to order rules from most to least specific. */
  63         list_add_rcu(&flow->u.node, &tl->flows);
  64         spin_unlock_irqrestore(&tl->lock, flags);
  65         return 1;
  66 }
  67
  68 static int do_delete(struct sw_table *swt, struct sw_flow *flow)
  69 {
  70         if (flow_del(flow)) {
  71                 list_del_rcu(&flow->u.node);
  72                 flow_deferred_free(flow);
  73                 return 1;
  74         }
  75         return 0;
  76 }
  77
  78 static int table_linear_delete(struct sw_table *swt,
  79                                 const struct sw_flow_key *key, int strict)
  80 {
  81         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
  82         struct list_head *pos, *n;
  83         unsigned int count = 0;
  84
  85         list_for_each_safe_rcu (pos, n, &tl->flows) {
  86                 struct sw_flow *flow = list_entry(pos, struct sw_flow, u.node);
  87                 if (flow_del_matches(&flow->key, key, strict))
  88                         count += do_delete(swt, flow);
  89         }
  90         if (count)
  91                 atomic_sub(count, &tl->n_flows);
  92         return count;
  93 }
  94
  95 static int table_linear_timeout(struct datapath *dp, struct sw_table *swt)
  96 {
  97         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
  98         struct list_head *pos, *n;
  99         int count = 0;
 100
 101         list_for_each_safe_rcu (pos, n, &tl->flows) {
 102                 struct sw_flow *flow = list_entry(pos, struct sw_flow, u.node);
 103                 if (flow_timeout(flow)) {
 104                         count += do_delete(swt, flow);
 105                         if (dp->hello_flags & OFP_CHELLO_SEND_FLOW_EXP)
 106                                 dp_send_flow_expired(dp, flow);
 107                 }
 108         }
 109         if (count)
 110                 atomic_sub(count, &tl->n_flows);
 111         return count;
 112 }
 113
 114 static void table_linear_destroy(struct sw_table *swt)
 115 {
 116         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 117
 118         while (!list_empty(&tl->flows)) {
 119                 struct sw_flow *flow = list_entry(tl->flows.next,
 120                                                   struct sw_flow, u.node);
 121                 list_del(&flow->u.node);
 122                 flow_free(flow);
 123         }
 124         kfree(tl);
 125 }
 126
 127 /* Linear table's private data is just a pointer to the table */
 128
 129 static int table_linear_iterator(struct sw_table *swt,
 130                                  struct swt_iterator *swt_iter)
 131 {
 132         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 133
 134         swt_iter->private = tl;
 135
 136         if (atomic_read(&tl->n_flows) == 0)
 137                 swt_iter->flow = NULL;
 138         else
 139                 swt_iter->flow = list_entry(tl->flows.next,
 140                                 struct sw_flow, u.node);
 141
 142         return 1;
 143 }
 144
 145 static void table_linear_next(struct swt_iterator *swt_iter)
 146 {
 147         struct sw_table_linear *tl;
 148         struct list_head *next;
 149
 150         if (swt_iter->flow == NULL)
 151                 return;
 152
 153         tl = (struct sw_table_linear *) swt_iter->private;
 154
 155         next = swt_iter->flow->u.node.next;
 156         if (next == &tl->flows)
 157                 swt_iter->flow = NULL;
 158         else
 159                 swt_iter->flow = list_entry(next, struct sw_flow, u.node);
 160 }
 161
 162 static void table_linear_iterator_destroy(struct swt_iterator *swt_iter)
 163 {}
 164
 165 static void table_linear_stats(struct sw_table *swt,
 166                                 struct sw_table_stats *stats)
 167 {
 168         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 169         stats->name = "linear";
 170         stats->n_flows = atomic_read(&tl->n_flows);
 171         stats->max_flows = tl->max_flows;
 172 }
 173
 174
 175 struct sw_table *table_linear_create(unsigned int max_flows)
 176 {
 177         struct sw_table_linear *tl;
 178         struct sw_table *swt;
 179
 180         tl = kzalloc(sizeof *tl, GFP_KERNEL);
 181         if (tl == NULL)
 182                 return NULL;
 183
 184         swt = &tl->swt;
 185         swt->lookup = table_linear_lookup;
 186         swt->insert = table_linear_insert;
 187         swt->delete = table_linear_delete;
 188         swt->timeout = table_linear_timeout;
 189         swt->destroy = table_linear_destroy;
 190         swt->stats = table_linear_stats;
 191
 192                 swt->iterator = table_linear_iterator;
 193         swt->iterator_next = table_linear_next;
 194         swt->iterator_destroy = table_linear_iterator_destroy;
 195
 196         tl->max_flows = max_flows;
 197         atomic_set(&tl->n_flows, 0);
 198         INIT_LIST_HEAD(&tl->flows);
 199         spin_lock_init(&tl->lock);
 200
 201         return swt;
 202 }