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
  43         /* Loop through the existing list of entries.  New entries will
  44          * always be placed behind those with equal priority.  Just replace
  45          * any flows that match exactly.
  46          */
  47         spin_lock_irqsave(&tl->lock, flags);
  48         list_for_each_entry_rcu (f, &tl->flows, u.node) {
  49                 if (f->priority == flow->priority
  50                                 && f->key.wildcards == flow->key.wildcards
  51                                 && flow_matches(&f->key, &flow->key)
  52                                 && flow_del(f)) {
  53                         list_replace_rcu(&f->u.node, &flow->u.node);
  54                         spin_unlock_irqrestore(&tl->lock, flags);
  55                         flow_deferred_free(f);
  56                         return 1;
  57                 }
  58
  59                 if (f->priority < flow->priority)
  60                         break;
  61         }
  62
  63         /* Make sure there's room in the table. */
  64         if (atomic_read(&tl->n_flows) >= tl->max_flows) {
  65                 spin_unlock_irqrestore(&tl->lock, flags);
  66                 return 0;
  67         }
  68         atomic_inc(&tl->n_flows);
  69
  70         /* Insert the entry immediately in front of where we're pointing. */
  71         list_add_tail_rcu(&flow->u.node, &f->u.node);
  72         spin_unlock_irqrestore(&tl->lock, flags);
  73         return 1;
  74 }
  75
  76 static int do_delete(struct sw_table *swt, struct sw_flow *flow)
  77 {
  78         if (flow_del(flow)) {
  79                 list_del_rcu(&flow->u.node);
  80                 flow_deferred_free(flow);
  81                 return 1;
  82         }
  83         return 0;
  84 }
  85
  86 static int table_linear_delete(struct sw_table *swt,
  87                                 const struct sw_flow_key *key, int strict)
  88 {
  89         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
  90         struct list_head *pos, *n;
  91         unsigned int count = 0;
  92
  93         list_for_each_safe_rcu (pos, n, &tl->flows) {
  94                 struct sw_flow *flow = list_entry(pos, struct sw_flow, u.node);
  95                 if (flow_del_matches(&flow->key, key, strict))
  96                         count += do_delete(swt, flow);
  97         }
  98         if (count)
  99                 atomic_sub(count, &tl->n_flows);
 100         return count;
 101 }
 102
 103 static int table_linear_timeout(struct datapath *dp, struct sw_table *swt)
 104 {
 105         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 106         struct list_head *pos, *n;
 107         int count = 0;
 108
 109         list_for_each_safe_rcu (pos, n, &tl->flows) {
 110                 struct sw_flow *flow = list_entry(pos, struct sw_flow, u.node);
 111                 if (flow_timeout(flow)) {
 112                         count += do_delete(swt, flow);
 113                         if (dp->flags & OFPC_SEND_FLOW_EXP)
 114                                 dp_send_flow_expired(dp, flow);
 115                 }
 116         }
 117         if (count)
 118                 atomic_sub(count, &tl->n_flows);
 119         return count;
 120 }
 121
 122 static void table_linear_destroy(struct sw_table *swt)
 123 {
 124         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 125
 126         while (!list_empty(&tl->flows)) {
 127                 struct sw_flow *flow = list_entry(tl->flows.next,
 128                                                   struct sw_flow, u.node);
 129                 list_del(&flow->u.node);
 130                 flow_free(flow);
 131         }
 132         kfree(tl);
 133 }
 134
 135 /* Linear table's private data is just a pointer to the table */
 136
 137 static int table_linear_iterator(struct sw_table *swt,
 138                                  struct swt_iterator *swt_iter)
 139 {
 140         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 141
 142         swt_iter->private = tl;
 143
 144         if (atomic_read(&tl->n_flows) == 0)
 145                 swt_iter->flow = NULL;
 146         else
 147                 swt_iter->flow = list_entry(tl->flows.next,
 148                                 struct sw_flow, u.node);
 149
 150         return 1;
 151 }
 152
 153 static void table_linear_next(struct swt_iterator *swt_iter)
 154 {
 155         struct sw_table_linear *tl;
 156         struct list_head *next;
 157
 158         if (swt_iter->flow == NULL)
 159                 return;
 160
 161         tl = (struct sw_table_linear *) swt_iter->private;
 162
 163         next = swt_iter->flow->u.node.next;
 164         if (next == &tl->flows)
 165                 swt_iter->flow = NULL;
 166         else
 167                 swt_iter->flow = list_entry(next, struct sw_flow, u.node);
 168 }
 169
 170 static void table_linear_iterator_destroy(struct swt_iterator *swt_iter)
 171 {}
 172
 173 static void table_linear_stats(struct sw_table *swt,
 174                                 struct sw_table_stats *stats)
 175 {
 176         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 177         stats->name = "linear";
 178         stats->n_flows = atomic_read(&tl->n_flows);
 179         stats->max_flows = tl->max_flows;
 180 }
 181
 182
 183 struct sw_table *table_linear_create(unsigned int max_flows)
 184 {
 185         struct sw_table_linear *tl;
 186         struct sw_table *swt;
 187
 188         tl = kzalloc(sizeof *tl, GFP_KERNEL);
 189         if (tl == NULL)
 190                 return NULL;
 191
 192         swt = &tl->swt;
 193         swt->lookup = table_linear_lookup;
 194         swt->insert = table_linear_insert;
 195         swt->delete = table_linear_delete;
 196         swt->timeout = table_linear_timeout;
 197         swt->destroy = table_linear_destroy;
 198         swt->stats = table_linear_stats;
 199
 200                 swt->iterator = table_linear_iterator;
 201         swt->iterator_next = table_linear_next;
 202         swt->iterator_destroy = table_linear_iterator_destroy;
 203
 204         tl->max_flows = max_flows;
 205         atomic_set(&tl->n_flows, 0);
 206         INIT_LIST_HEAD(&tl->flows);
 207         spin_lock_init(&tl->lock);
 208
 209         return swt;
 210 }