net/batman-adv/originator.h

   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
  25 int batadv_originator_init(struct batadv_priv *bat_priv);
  26 void batadv_originator_free(struct batadv_priv *bat_priv);
  27 void batadv_purge_orig_ref(struct batadv_priv *bat_priv);
  28 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node);
  29 struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
  30                                               const uint8_t *addr);
  31 struct batadv_neigh_node *
  32 batadv_neigh_node_new(struct batadv_hard_iface *hard_iface,
  33                       const uint8_t *neigh_addr, uint32_t seqno);
  34 void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node);
  35 struct batadv_neigh_node *
  36 batadv_orig_node_get_router(struct batadv_orig_node *orig_node);
  37 int batadv_orig_seq_print_text(struct seq_file *seq, void *offset);
  38 int batadv_orig_hash_add_if(struct batadv_hard_iface *hard_iface,
  39                             int max_if_num);
  40 int 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  */
  47 static 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
  66 static inline struct batadv_orig_node *
  67 batadv_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_ */