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, uint8_t *addr);
  32 struct neigh_node *create_neighbor(struct orig_node *orig_node,
  33                                    struct orig_node *orig_neigh_node,
  34                                    uint8_t *neigh,
  35                                    struct hard_iface *if_incoming);
  36 void neigh_node_free_ref(struct neigh_node *neigh_node);
  37 int orig_seq_print_text(struct seq_file *seq, void *offset);
  38 int orig_hash_add_if(struct hard_iface *hard_iface, int max_if_num);
  39 int orig_hash_del_if(struct hard_iface *hard_iface, int max_if_num);
  40
  41
  42 /* returns 1 if they are the same originator */
  43 static inline int compare_orig(struct hlist_node *node, void *data2)
  44 {
  45         void *data1 = container_of(node, struct orig_node, hash_entry);
  46
  47         return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
  48 }
  49
  50 /* hashfunction to choose an entry in a hash table of given size */
  51 /* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */
  52 static inline int choose_orig(void *data, int32_t size)
  53 {
  54         unsigned char *key = data;
  55         uint32_t hash = 0;
  56         size_t i;
  57
  58         for (i = 0; i < 6; i++) {
  59                 hash += key[i];
  60                 hash += (hash << 10);
  61                 hash ^= (hash >> 6);
  62         }
  63
  64         hash += (hash << 3);
  65         hash ^= (hash >> 11);
  66         hash += (hash << 15);
  67
  68         return hash % size;
  69 }
  70
  71 static inline struct orig_node *orig_hash_find(struct bat_priv *bat_priv,
  72                                                void *data)
  73 {
  74         struct hashtable_t *hash = bat_priv->orig_hash;
  75         struct hlist_head *head;
  76         struct hlist_node *node;
  77         struct orig_node *orig_node, *orig_node_tmp = NULL;
  78         int index;
  79
  80         if (!hash)
  81                 return NULL;
  82
  83         index = choose_orig(data, hash->size);
  84         head = &hash->table[index];
  85
  86         rcu_read_lock();
  87         hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
  88                 if (!compare_eth(orig_node, data))
  89                         continue;
  90
  91                 if (!atomic_inc_not_zero(&orig_node->refcount))
  92                         continue;
  93
  94                 orig_node_tmp = orig_node;
  95                 break;
  96         }
  97         rcu_read_unlock();
  98
  99         return orig_node_tmp;
 100 }
 101
 102 #endif /* _NET_BATMAN_ADV_ORIGINATOR_H_ */