path: root/net/batman-adv/routing.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich
 */

#include "routing.h"
#include "main.h"

#include <linux/atomic.h>
#include <linux/byteorder/generic.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/jiffies.h>
#include <linux/kref.h>
#include <linux/netdevice.h>
#include <linux/printk.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <uapi/linux/batadv_packet.h>

#include "bitarray.h"
#include "bridge_loop_avoidance.h"
#include "distributed-arp-table.h"
#include "fragmentation.h"
#include "hard-interface.h"
#include "log.h"
#include "network-coding.h"
#include "originator.h"
#include "send.h"
#include "soft-interface.h"
#include "tp_meter.h"
#include "translation-table.h"
#include "tvlv.h"

static int batadv_route_unicast_packet(struct sk_buff *skb,
				       struct batadv_hard_iface *recv_if);

/**
 * _batadv_update_route() - set the router for this originator
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: orig node which is to be configured
 * @recv_if: the receive interface for which this route is set
 * @neigh_node: neighbor which should be the next router
 *
 * This function does not perform any error checks
 */
static void _batadv_update_route(struct batadv_priv *bat_priv,
				 struct batadv_orig_node *orig_node,
				 struct batadv_hard_iface *recv_if,
				 struct batadv_neigh_node *neigh_node)
{
	struct batadv_orig_ifinfo *orig_ifinfo;
	struct batadv_neigh_node *curr_router;

	orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
	if (!orig_ifinfo)
		return;

	spin_lock_bh(&orig_node->neigh_list_lock);
	/* curr_router used earlier may not be the current orig_ifinfo->router
	 * anymore because it was dereferenced outside of the neigh_list_lock
	 * protected region. After the new best neighbor has replace the current
	 * best neighbor the reference counter needs to decrease. Consequently,
	 * the code needs to ensure the curr_router variable contains a pointer
	 * to the replaced best neighbor.
	 */

	/* increase refcount of new best neighbor */
	if (neigh_node)
		kref_get(&neigh_node->refcount);

	curr_router = rcu_replace_pointer(orig_ifinfo->router, neigh_node,
					  true);
	spin_unlock_bh(&orig_node->neigh_list_lock);
	batadv_orig_ifinfo_put(orig_ifinfo);

	/* route deleted */
	if (curr_router && !neigh_node) {
		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
			   "Deleting route towards: %pM\n", orig_node->orig);
		batadv_tt_global_del_orig(bat_priv, orig_node, -1,
					  "Deleted route towards originator");

	/* route added */
	} else if (!curr_router && neigh_node) {
		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
			   "Adding route towards: %pM (via %pM)\n",
			   orig_node->orig, neigh_node->addr);
	/* route changed */
	} else if (neigh_node && curr_router) {
		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
			   "Changing route towards: %pM (now via %pM - was via %pM)\n",
			   orig_node->orig, neigh_node->