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/rculist.h>
  14
  15 struct sw_table_linear {
  16         struct sw_table swt;
  17
  18         unsigned int max_flows;
  19         unsigned int n_flows;
  20         struct list_head flows;
  21         struct list_head iter_flows;
  22         unsigned long int next_serial;
  23 };
  24
  25 static struct sw_flow *table_linear_lookup(struct sw_table *swt,
  26                                          const struct sw_flow_key *key)
  27 {
  28         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
  29         struct sw_flow *flow;
  30         list_for_each_entry_rcu (flow, &tl->flows, node) {
  31                 if (flow_matches_1wild(key, &flow->key))
  32                         return flow;
  33         }
  34         return NULL;
  35 }
  36
  37 static int table_linear_insert(struct sw_table *swt, struct sw_flow *flow)
  38 {
  39         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
  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         list_for_each_entry (f, &tl->flows, node) {
  48                 if (f->priority == flow->priority
  49                                 && f->key.wildcards == flow->key.wildcards
  50                                 && flow_matches_2wild(&f->key, &flow->key)) {
  51                         /* Keep stats from the original flow */
  52                         flow->init_time = f->init_time;
  53                         flow->packet_count = f->packet_count;
  54                         flow->byte_count = f->byte_count;
  55
  56                         flow->serial = f->serial;
  57                         list_replace_rcu(&f->node, &flow->node);
  58                         list_replace_rcu(&f->iter_node, &flow->iter_node);
  59                         flow_deferred_free(f);
  60                         return 1;
  61                 }
  62
  63                 if (f->priority < flow->priority)
  64                         break;
  65         }
  66
  67         /* Make sure there's room in the table. */
  68         if (tl->n_flows >= tl->max_flows) {
  69                 return 0;
  70         }
  71         tl->n_flows++;
  72
  73         /* Insert the entry immediately in front of where we're pointing. */
  74         flow->serial = tl->next_serial++;
  75         list_add_tail_rcu(&flow->node, &f->node);
  76         list_add_rcu(&flow->iter_node, &tl->iter_flows);
  77         return 1;
  78 }
  79
  80 static int do_delete(struct sw_table *swt, struct sw_flow *flow)
  81 {
  82         list_del_rcu(&flow->node);
  83         list_del_rcu(&flow->iter_node);
  84         flow_deferred_free(flow);
  85         return 1;
  86 }
  87
  88 static int table_linear_delete(struct sw_table *swt,
  89                                 const struct sw_flow_key *key, uint16_t priority, int strict)
  90 {
  91         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
  92         struct sw_flow *flow;
  93         unsigned int count = 0;
  94
  95         list_for_each_entry (flow, &tl->flows, node) {
  96                 if (flow_del_matches(&flow->key, key, strict)
  97                                 && (!strict || (flow->priority == priority)))
  98                         count += do_delete(swt, flow);
  99         }
 100         tl->n_flows -= count;
 101         return count;
 102 }
 103
 104 static int table_linear_timeout(struct datapath *dp, struct sw_table *swt)
 105 {
 106         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 107         struct sw_flow *flow;
 108         int count = 0;
 109
 110         mutex_lock(&dp_mutex);
 111         list_for_each_entry (flow, &tl->flows, node) {
 112                 int reason = flow_timeout(flow);
 113                 if (reason >= 0) {
 114                         count += do_delete(swt, flow);
 115                         dp_send_flow_expired(dp, flow, reason);
 116                 }
 117         }
 118         tl->n_flows -= count;
 119         mutex_unlock(&dp_mutex);
 120         return count;
 121 }
 122
 123 static void table_linear_destroy(struct sw_table *swt)
 124 {
 125         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 126
 127         while (!list_empty(&tl->flows)) {
 128                 struct sw_flow *flow = list_entry(tl->flows.next,
 129                                                   struct sw_flow, node);
 130                 list_del(&flow->node);
 131                 flow_free(flow);
 132         }
 133         kfree(tl);
 134 }
 135
 136 static int table_linear_iterate(struct sw_table *swt,
 137                                 const struct sw_flow_key *key,
 138                                 struct sw_table_position *position,
 139                                 int (*callback)(struct sw_flow *, void *),
 140                                 void *private)
 141 {
 142         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 143         struct sw_flow *flow;
 144         unsigned long start;
 145
 146         start = position->private[0];
 147         list_for_each_entry (flow, &tl->iter_flows, iter_node) {
 148                 if (flow->serial >= start
 149                     && flow_matches_2wild(key, &flow->key)) {
 150                         int error = callback(flow, private);
 151                         if (error) {
 152                                 position->private[0] = flow->serial;
 153                                 return error;
 154                         }
 155                 }
 156         }
 157         return 0;
 158 }
 159
 160 static void table_linear_stats(struct sw_table *swt,
 161                                 struct sw_table_stats *stats)
 162 {
 163         struct sw_table_linear *tl = (struct sw_table_linear *) swt;
 164         stats->name = "linear";
 165         stats->wildcards = OFPFW_ALL;
 166         stats->n_flows   = tl->n_flows;
 167         stats->max_flows = tl->max_flows;
 168         stats->n_matched = swt->n_matched;
 169 }
 170
 171
 172 struct sw_table *table_linear_create(unsigned int max_flows)
 173 {
 174         struct sw_table_linear *tl;
 175         struct sw_table *swt;
 176
 177         tl = kzalloc(sizeof *tl, GFP_KERNEL);
 178         if (tl == NULL)
 179                 return NULL;
 180
 181         swt = &tl->swt;
 182         swt->lookup = table_linear_lookup;
 183         swt->insert = table_linear_insert;
 184         swt->delete = table_linear_delete;
 185         swt->timeout = table_linear_timeout;
 186         swt->destroy = table_linear_destroy;
 187         swt->iterate = table_linear_iterate;
 188         swt->stats = table_linear_stats;
 189
 190         tl->max_flows = max_flows;
 191         tl->n_flows = 0;
 192         INIT_LIST_HEAD(&tl->flows);
 193         INIT_LIST_HEAD(&tl->iter_flows);
 194         tl->next_serial = 0;
 195
 196         return swt;
 197 }