linux/net/batman-adv/main.c
Simon Wunderlich 23721387c4 batman-adv: add basic bridge loop avoidance code
This second version of the bridge loop avoidance for batman-adv
avoids loops between the mesh and a backbone (usually a LAN).

By connecting multiple batman-adv mesh nodes to the same ethernet
segment a loop can be created when the soft-interface is bridged
into that ethernet segment. A simple visualization of the loop
involving the most common case - a LAN as ethernet segment:

node1  <-- LAN  -->  node2
  |                   |
wifi   <-- mesh -->  wifi

Packets from the LAN (e.g. ARP broadcasts) will circle forever from
node1 or node2 over the mesh back into the LAN.

With this patch, batman recognizes backbone gateways, nodes which are
part of the mesh and backbone/LAN at the same time. Each backbone
gateway "claims" clients from within the mesh to handle them
exclusively. By restricting that only responsible backbone gateways
may handle their claimed clients traffic, loops are effectively
avoided.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
2012-04-11 14:28:58 +02:00

293 lines
6.7 KiB
C

/*
* 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
*
*/
#include "main.h"
#include "bat_sysfs.h"
#include "bat_debugfs.h"
#include "routing.h"
#include "send.h"
#include "originator.h"
#include "soft-interface.h"
#include "icmp_socket.h"
#include "translation-table.h"
#include "hard-interface.h"
#include "gateway_client.h"
#include "bridge_loop_avoidance.h"
#include "vis.h"
#include "hash.h"
#include "bat_algo.h"
/* List manipulations on hardif_list have to be rtnl_lock()'ed,
* list traversals just rcu-locked */
struct list_head hardif_list;
char bat_routing_algo[20] = "BATMAN IV";
static struct hlist_head bat_algo_list;
unsigned char broadcast_addr[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
struct workqueue_struct *bat_event_workqueue;
static int __init batman_init(void)
{
INIT_LIST_HEAD(&hardif_list);
INIT_HLIST_HEAD(&bat_algo_list);
bat_iv_init();
/* the name should not be longer than 10 chars - see
* http://lwn.net/Articles/23634/ */
bat_event_workqueue = create_singlethread_workqueue("bat_events");
if (!bat_event_workqueue)
return -ENOMEM;
bat_socket_init();
debugfs_init();
register_netdevice_notifier(&hard_if_notifier);
pr_info("B.A.T.M.A.N. advanced %s (compatibility version %i) loaded\n",
SOURCE_VERSION, COMPAT_VERSION);
return 0;
}
static void __exit batman_exit(void)
{
debugfs_destroy();
unregister_netdevice_notifier(&hard_if_notifier);
hardif_remove_interfaces();
flush_workqueue(bat_event_workqueue);
destroy_workqueue(bat_event_workqueue);
bat_event_workqueue = NULL;
rcu_barrier();
}
int mesh_init(struct net_device *soft_iface)
{
struct bat_priv *bat_priv = netdev_priv(soft_iface);
spin_lock_init(&bat_priv->forw_bat_list_lock);
spin_lock_init(&bat_priv->forw_bcast_list_lock);
spin_lock_init(&bat_priv->tt_changes_list_lock);
spin_lock_init(&bat_priv->tt_req_list_lock);
spin_lock_init(&bat_priv->tt_roam_list_lock);
spin_lock_init(&bat_priv->tt_buff_lock);
spin_lock_init(&bat_priv->gw_list_lock);
spin_lock_init(&bat_priv->vis_hash_lock);
spin_lock_init(&bat_priv->vis_list_lock);
INIT_HLIST_HEAD(&bat_priv->forw_bat_list);
INIT_HLIST_HEAD(&bat_priv->forw_bcast_list);
INIT_HLIST_HEAD(&bat_priv->gw_list);
INIT_LIST_HEAD(&bat_priv->tt_changes_list);
INIT_LIST_HEAD(&bat_priv->tt_req_list);
INIT_LIST_HEAD(&bat_priv->tt_roam_list);
if (originator_init(bat_priv) < 1)
goto err;
if (tt_init(bat_priv) < 1)
goto err;
tt_local_add(soft_iface, soft_iface->dev_addr, NULL_IFINDEX);
if (vis_init(bat_priv) < 1)
goto err;
if (bla_init(bat_priv) < 1)
goto err;
atomic_set(&bat_priv->gw_reselect, 0);
atomic_set(&bat_priv->mesh_state, MESH_ACTIVE);
goto end;
err:
mesh_free(soft_iface);
return -1;
end:
return 0;
}
void mesh_free(struct net_device *soft_iface)
{
struct bat_priv *bat_priv = netdev_priv(soft_iface);
atomic_set(&bat_priv->mesh_state, MESH_DEACTIVATING);
purge_outstanding_packets(bat_priv, NULL);
vis_quit(bat_priv);
gw_node_purge(bat_priv);
originator_free(bat_priv);
tt_free(bat_priv);
bla_free(bat_priv);
atomic_set(&bat_priv->mesh_state, MESH_INACTIVE);
}
void inc_module_count(void)
{
try_module_get(THIS_MODULE);
}
void dec_module_count(void)
{
module_put(THIS_MODULE);
}
int is_my_mac(const uint8_t *addr)
{
const struct hard_iface *hard_iface;
rcu_read_lock();
list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
if (hard_iface->if_status != IF_ACTIVE)
continue;
if (compare_eth(hard_iface->net_dev->dev_addr, addr)) {
rcu_read_unlock();
return 1;
}
}
rcu_read_unlock();
return 0;
}
static struct bat_algo_ops *bat_algo_get(char *name)
{
struct bat_algo_ops *bat_algo_ops = NULL, *bat_algo_ops_tmp;
struct hlist_node *node;
hlist_for_each_entry(bat_algo_ops_tmp, node, &bat_algo_list, list) {
if (strcmp(bat_algo_ops_tmp->name, name) != 0)
continue;
bat_algo_ops = bat_algo_ops_tmp;
break;
}
return bat_algo_ops;
}
int bat_algo_register(struct bat_algo_ops *bat_algo_ops)
{
struct bat_algo_ops *bat_algo_ops_tmp;
int ret = -1;
bat_algo_ops_tmp = bat_algo_get(bat_algo_ops->name);
if (bat_algo_ops_tmp) {
pr_info("Trying to register already registered routing algorithm: %s\n",
bat_algo_ops->name);
goto out;
}
/* all algorithms must implement all ops (for now) */
if (!bat_algo_ops->bat_ogm_init ||
!bat_algo_ops->bat_ogm_init_primary ||
!bat_algo_ops->bat_ogm_update_mac ||
!bat_algo_ops->bat_ogm_schedule ||
!bat_algo_ops->bat_ogm_emit ||
!bat_algo_ops->bat_ogm_receive) {
pr_info("Routing algo '%s' does not implement required ops\n",
bat_algo_ops->name);
goto out;
}
INIT_HLIST_NODE(&bat_algo_ops->list);
hlist_add_head(&bat_algo_ops->list, &bat_algo_list);
ret = 0;
out:
return ret;
}
int bat_algo_select(struct bat_priv *bat_priv, char *name)
{
struct bat_algo_ops *bat_algo_ops;
int ret = -1;
bat_algo_ops = bat_algo_get(name);
if (!bat_algo_ops)
goto out;
bat_priv->bat_algo_ops = bat_algo_ops;
ret = 0;
out:
return ret;
}
int bat_algo_seq_print_text(struct seq_file *seq, void *offset)
{
struct bat_algo_ops *bat_algo_ops;
struct hlist_node *node;
seq_printf(seq, "Available routing algorithms:\n");
hlist_for_each_entry(bat_algo_ops, node, &bat_algo_list, list) {
seq_printf(seq, "%s\n", bat_algo_ops->name);
}
return 0;
}
static int param_set_ra(const char *val, const struct kernel_param *kp)
{
struct bat_algo_ops *bat_algo_ops;
bat_algo_ops = bat_algo_get((char *)val);
if (!bat_algo_ops) {
pr_err("Routing algorithm '%s' is not supported\n", val);
return -EINVAL;
}
return param_set_copystring(val, kp);
}
static const struct kernel_param_ops param_ops_ra = {
.set = param_set_ra,
.get = param_get_string,
};
static struct kparam_string __param_string_ra = {
.maxlen = sizeof(bat_routing_algo),
.string = bat_routing_algo,
};
module_param_cb(routing_algo, &param_ops_ra, &__param_string_ra, 0644);
module_init(batman_init);
module_exit(batman_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_SUPPORTED_DEVICE(DRIVER_DEVICE);
MODULE_VERSION(SOURCE_VERSION);