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linux-next/net/batman-adv/originator.h
Linus Lüssing e1a5382f97 batman-adv: Make orig_node->router an rcu protected pointer
The rcu protected macros rcu_dereference() and rcu_assign_pointer()
for the orig_node->router need to be used, as well as spin/rcu locking.
Otherwise we might end up using a router pointer pointing to already
freed memory.

Therefore this commit introduces the safe getter method
orig_node_get_router().

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-04-17 21:11:01 +02:00

104 lines
2.9 KiB
C

/*
* Copyright (C) 2007-2011 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 originator_init(struct bat_priv *bat_priv);
void originator_free(struct bat_priv *bat_priv);
void purge_orig_ref(struct bat_priv *bat_priv);
void orig_node_free_ref(struct orig_node *orig_node);
struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr);
struct neigh_node *create_neighbor(struct orig_node *orig_node,
struct orig_node *orig_neigh_node,
uint8_t *neigh,
struct hard_iface *if_incoming);
void neigh_node_free_ref(struct neigh_node *neigh_node);
struct neigh_node *orig_node_get_router(struct orig_node *orig_node);
int orig_seq_print_text(struct seq_file *seq, void *offset);
int orig_hash_add_if(struct hard_iface *hard_iface, int max_if_num);
int orig_hash_del_if(struct hard_iface *hard_iface, int max_if_num);
/* returns 1 if they are the same originator */
static inline int compare_orig(struct hlist_node *node, void *data2)
{
void *data1 = container_of(node, struct orig_node, hash_entry);
return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
}
/* hashfunction to choose an entry in a hash table of given size */
/* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */
static inline int choose_orig(void *data, int32_t size)
{
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 orig_node *orig_hash_find(struct bat_priv *bat_priv,
void *data)
{
struct hashtable_t *hash = bat_priv->orig_hash;
struct hlist_head *head;
struct hlist_node *node;
struct orig_node *orig_node, *orig_node_tmp = NULL;
int index;
if (!hash)
return NULL;
index = choose_orig(data, hash->size);
head = &hash->table[index];
rcu_read_lock();
hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
if (!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_ */