linux/net/batman-adv/originator.h
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   1/* Copyright (C) 2007-2012 B.A.T.M.A.N. contributors:
   2 *
   3 * Marek Lindner, Simon Wunderlich
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of version 2 of the GNU General Public
   7 * License as published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it will be useful, but
  10 * WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12 * General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17 * 02110-1301, USA
  18 */
  19
  20#ifndef _NET_BATMAN_ADV_ORIGINATOR_H_
  21#define _NET_BATMAN_ADV_ORIGINATOR_H_
  22
  23#include "hash.h"
  24
  25int batadv_originator_init(struct batadv_priv *bat_priv);
  26void batadv_originator_free(struct batadv_priv *bat_priv);
  27void batadv_purge_orig_ref(struct batadv_priv *bat_priv);
  28void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node);
  29struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
  30                                              const uint8_t *addr);
  31struct batadv_neigh_node *
  32batadv_neigh_node_new(struct batadv_hard_iface *hard_iface,
  33                      const uint8_t *neigh_addr, uint32_t seqno);
  34void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node);
  35struct batadv_neigh_node *
  36batadv_orig_node_get_router(struct batadv_orig_node *orig_node);
  37int batadv_orig_seq_print_text(struct seq_file *seq, void *offset);
  38int batadv_orig_hash_add_if(struct batadv_hard_iface *hard_iface,
  39                            int max_if_num);
  40int batadv_orig_hash_del_if(struct batadv_hard_iface *hard_iface,
  41                            int max_if_num);
  42
  43
  44/* hashfunction to choose an entry in a hash table of given size
  45 * hash algorithm from http://en.wikipedia.org/wiki/Hash_table
  46 */
  47static inline uint32_t batadv_choose_orig(const void *data, uint32_t size)
  48{
  49        const unsigned char *key = data;
  50        uint32_t hash = 0;
  51        size_t i;
  52
  53        for (i = 0; i < 6; i++) {
  54                hash += key[i];
  55                hash += (hash << 10);
  56                hash ^= (hash >> 6);
  57        }
  58
  59        hash += (hash << 3);
  60        hash ^= (hash >> 11);
  61        hash += (hash << 15);
  62
  63        return hash % size;
  64}
  65
  66static inline struct batadv_orig_node *
  67batadv_orig_hash_find(struct batadv_priv *bat_priv, const void *data)
  68{
  69        struct batadv_hashtable *hash = bat_priv->orig_hash;
  70        struct hlist_head *head;
  71        struct hlist_node *node;
  72        struct batadv_orig_node *orig_node, *orig_node_tmp = NULL;
  73        int index;
  74
  75        if (!hash)
  76                return NULL;
  77
  78        index = batadv_choose_orig(data, hash->size);
  79        head = &hash->table[index];
  80
  81        rcu_read_lock();
  82        hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
  83                if (!batadv_compare_eth(orig_node, data))
  84                        continue;
  85
  86                if (!atomic_inc_not_zero(&orig_node->refcount))
  87                        continue;
  88
  89                orig_node_tmp = orig_node;
  90                break;
  91        }
  92        rcu_read_unlock();
  93
  94        return orig_node_tmp;
  95}
  96
  97#endif /* _NET_BATMAN_ADV_ORIGINATOR_H_ */
  98
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