originator.h

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/* Copyright (C) 2007-2012 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#ifndef _NET_BATMAN_ADV_ORIGINATOR_H_
#define _NET_BATMAN_ADV_ORIGINATOR_H_

#include "hash.h"

int batadv_originator_init(struct batadv_priv *bat_priv);
void batadv_originator_free(struct batadv_priv *bat_priv);
void batadv_purge_orig_ref(struct batadv_priv *bat_priv);
void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node);
struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
                          const uint8_t *addr);
struct batadv_neigh_node *
batadv_neigh_node_new(struct batadv_hard_iface *hard_iface,
              const uint8_t *neigh_addr, uint32_t seqno);
void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node);
struct batadv_neigh_node *
batadv_orig_node_get_router(struct batadv_orig_node *orig_node);
int batadv_orig_seq_print_text(struct seq_file *seq, void *offset);
int batadv_orig_hash_add_if(struct batadv_hard_iface *hard_iface,
                int max_if_num);
int batadv_orig_hash_del_if(struct batadv_hard_iface *hard_iface,
                int max_if_num);


/* hashfunction to choose an entry in a hash table of given size
 * hash algorithm from http://en.wikipedia.org/wiki/Hash_table
 */
static inline uint32_t batadv_choose_orig(const void *data, uint32_t size)
{
    const unsigned char *key = data;
    uint32_t hash = 0;
    size_t i;

    for (i = 0; i < 6; i++) {
        hash += key[i];
        hash += (hash << 10);
        hash ^= (hash >> 6);
    }

    hash += (hash << 3);
    hash ^= (hash >> 11);
    hash += (hash << 15);

    return hash % size;
}

static inline struct batadv_orig_node *
batadv_orig_hash_find(struct batadv_priv *bat_priv, const void *data)
{
    struct batadv_hashtable *hash = bat_priv->orig_hash;
    struct hlist_head *head;
    struct hlist_node *node;
    struct batadv_orig_node *orig_node, *orig_node_tmp = NULL;
    int index;

    if (!hash)
        return NULL;

    index = batadv_choose_orig(data, hash->size);
    head = &hash->table[index];

    rcu_read_lock();
    hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
        if (!batadv_compare_eth(orig_node, data))
            continue;

        if (!atomic_inc_not_zero(&orig_node->refcount))
            continue;

        orig_node_tmp = orig_node;
        break;
    }
    rcu_read_unlock();

    return orig_node_tmp;
}

#endif /* _NET_BATMAN_ADV_ORIGINATOR_H_ */