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