net/batman-adv/originator.h

   1 /*
   2  * Copyright (C) 2007-2011 B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner, Simon Wunderlich
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #ifndef _NET_BATMAN_ADV_ORIGINATOR_H_
  23 #define _NET_BATMAN_ADV_ORIGINATOR_H_
  24
  25 #include "hash.h"
  26
  27 int originator_init(struct bat_priv *bat_priv);
  28 void originator_free(struct bat_priv *bat_priv);
  29 void purge_orig_ref(struct bat_priv *bat_priv);
  30 void orig_node_free_ref(struct orig_node *orig_node);
  31 struct orig_node *get_orig_node(struct bat_priv *bat_priv, const uint8_t *addr);
  32 struct neigh_node *create_neighbor(struct orig_node *orig_node,
  33                                    struct orig_node *orig_neigh_node,
  34                                    const uint8_t *neigh,
  35                                    struct hard_iface *if_incoming);
  36 void neigh_node_free_ref(struct neigh_node *neigh_node);
  37 struct neigh_node *orig_node_get_router(struct orig_node *orig_node);
  38 int orig_seq_print_text(struct seq_file *seq, void *offset);
  39 int orig_hash_add_if(struct hard_iface *hard_iface, int max_if_num);
  40 int orig_hash_del_if(struct hard_iface *hard_iface, int max_if_num);
  41
  42
  43 /* hashfunction to choose an entry in a hash table of given size */
  44 /* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */
  45 static inline int choose_orig(const void *data, int32_t size)
  46 {
  47         const unsigned char *key = data;
  48         uint32_t hash = 0;
  49         size_t i;
  50
  51         for (i = 0; i < 6; i++) {
  52                 hash += key[i];
  53                 hash += (hash << 10);
  54                 hash ^= (hash >> 6);
  55         }
  56
  57         hash += (hash << 3);
  58         hash ^= (hash >> 11);
  59         hash += (hash << 15);
  60
  61         return hash % size;
  62 }
  63
  64 static inline struct orig_node *orig_hash_find(struct bat_priv *bat_priv,
  65                                                const void *data)
  66 {
  67         struct hashtable_t *hash = bat_priv->orig_hash;
  68         struct hlist_head *head;
  69         struct hlist_node *node;
  70         struct orig_node *orig_node, *orig_node_tmp = NULL;
  71         int index;
  72
  73         if (!hash)
  74                 return NULL;
  75
  76         index = choose_orig(data, hash->size);
  77         head = &hash->table[index];
  78
  79         rcu_read_lock();
  80         hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
  81                 if (!compare_eth(orig_node, data))
  82                         continue;
  83
  84                 if (!atomic_inc_not_zero(&orig_node->refcount))
  85                         continue;
  86
  87                 orig_node_tmp = orig_node;
  88                 break;
  89         }
  90         rcu_read_unlock();
  91
  92         return orig_node_tmp;
  93 }
  94
  95 #endif /* _NET_BATMAN_ADV_ORIGINATOR_H_ */