network-coding.c 58 KB
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/* Copyright (C) 2012-2015 B.A.T.M.A.N. contributors:
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 *
 * Martin Hundebøll, Jeppe Ledet-Pedersen
 *
 * 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
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 * along with this program; if not, see <http://www.gnu.org/licenses/>.
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 */

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#include "network-coding.h"
#include "main.h"

#include <linux/atomic.h>
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#include <linux/bitops.h>
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#include <linux/byteorder/generic.h>
#include <linux/compiler.h>
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#include <linux/debugfs.h>
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#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/fs.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stat.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/workqueue.h>
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#include "hard-interface.h"
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#include "hash.h"
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#include "originator.h"
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#include "packet.h"
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#include "routing.h"
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#include "send.h"
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static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
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static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
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static void batadv_nc_worker(struct work_struct *work);
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static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
				       struct batadv_hard_iface *recv_if);
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/**
 * batadv_nc_init - one-time initialization for network coding
 */
int __init batadv_nc_init(void)
{
	int ret;

	/* Register our packet type */
	ret = batadv_recv_handler_register(BATADV_CODED,
					   batadv_nc_recv_coded_packet);

	return ret;
}

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/**
 * batadv_nc_start_timer - initialise the nc periodic worker
 * @bat_priv: the bat priv with all the soft interface information
 */
static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
{
	queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
			   msecs_to_jiffies(10));
}

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/**
 * batadv_nc_tvlv_container_update - update the network coding tvlv container
 *  after network coding setting change
 * @bat_priv: the bat priv with all the soft interface information
 */
static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
{
	char nc_mode;

	nc_mode = atomic_read(&bat_priv->network_coding);

	switch (nc_mode) {
	case 0:
		batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
		break;
	case 1:
		batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
					       NULL, 0);
		break;
	}
}

/**
 * batadv_nc_status_update - update the network coding tvlv container after
 *  network coding setting change
 * @net_dev: the soft interface net device
 */
void batadv_nc_status_update(struct net_device *net_dev)
{
	struct batadv_priv *bat_priv = netdev_priv(net_dev);
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	batadv_nc_tvlv_container_update(bat_priv);
}

/**
 * batadv_nc_tvlv_ogm_handler_v1 - process incoming nc tvlv container
 * @bat_priv: the bat priv with all the soft interface information
 * @orig: the orig_node of the ogm
 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
 * @tvlv_value: tvlv buffer containing the gateway data
 * @tvlv_value_len: tvlv buffer length
 */
static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
					  struct batadv_orig_node *orig,
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					  u8 flags,
					  void *tvlv_value, u16 tvlv_value_len)
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{
	if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
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		clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
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	else
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		set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
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}

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/**
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 * batadv_nc_mesh_init - initialise coding hash table and start house keeping
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 * @bat_priv: the bat priv with all the soft interface information
 */
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int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
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{
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	bat_priv->nc.timestamp_fwd_flush = jiffies;
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	bat_priv->nc.timestamp_sniffed_purge = jiffies;
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	if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
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		return 0;

	bat_priv->nc.coding_hash = batadv_hash_new(128);
	if (!bat_priv->nc.coding_hash)
		goto err;

	batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
				   &batadv_nc_coding_hash_lock_class_key);

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	bat_priv->nc.decoding_hash = batadv_hash_new(128);
	if (!bat_priv->nc.decoding_hash)
		goto err;

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	batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
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				   &batadv_nc_decoding_hash_lock_class_key);

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	INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
	batadv_nc_start_timer(bat_priv);

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	batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
				     NULL, BATADV_TVLV_NC, 1,
				     BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
	batadv_nc_tvlv_container_update(bat_priv);
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	return 0;
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err:
	return -ENOMEM;
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}

/**
 * batadv_nc_init_bat_priv - initialise the nc specific bat_priv variables
 * @bat_priv: the bat priv with all the soft interface information
 */
void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
{
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	atomic_set(&bat_priv->network_coding, 0);
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	bat_priv->nc.min_tq = 200;
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	bat_priv->nc.max_fwd_delay = 10;
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	bat_priv->nc.max_buffer_time = 200;
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}

/**
 * batadv_nc_init_orig - initialise the nc fields of an orig_node
 * @orig_node: the orig_node which is going to be initialised
 */
void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
{
	INIT_LIST_HEAD(&orig_node->in_coding_list);
	INIT_LIST_HEAD(&orig_node->out_coding_list);
	spin_lock_init(&orig_node->in_coding_list_lock);
	spin_lock_init(&orig_node->out_coding_list_lock);
}

/**
 * batadv_nc_node_free_rcu - rcu callback to free an nc node and remove
 *  its refcount on the orig_node
 * @rcu: rcu pointer of the nc node
 */
static void batadv_nc_node_free_rcu(struct rcu_head *rcu)
{
	struct batadv_nc_node *nc_node;

	nc_node = container_of(rcu, struct batadv_nc_node, rcu);
	batadv_orig_node_free_ref(nc_node->orig_node);
	kfree(nc_node);
}

/**
 * batadv_nc_node_free_ref - decrements the nc node refcounter and possibly
 * frees it
 * @nc_node: the nc node to free
 */
static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node)
{
	if (atomic_dec_and_test(&nc_node->refcount))
		call_rcu(&nc_node->rcu, batadv_nc_node_free_rcu);
}

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/**
 * batadv_nc_path_free_ref - decrements the nc path refcounter and possibly
 * frees it
 * @nc_path: the nc node to free
 */
static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path)
{
	if (atomic_dec_and_test(&nc_path->refcount))
		kfree_rcu(nc_path, rcu);
}

/**
 * batadv_nc_packet_free - frees nc packet
 * @nc_packet: the nc packet to free
 */
static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet)
{
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	kfree_skb(nc_packet->skb);
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	batadv_nc_path_free_ref(nc_packet->nc_path);
	kfree(nc_packet);
}

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/**
 * batadv_nc_to_purge_nc_node - checks whether an nc node has to be purged
 * @bat_priv: the bat priv with all the soft interface information
 * @nc_node: the nc node to check
 *
 * Returns true if the entry has to be purged now, false otherwise
 */
static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
				       struct batadv_nc_node *nc_node)
{
	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
		return true;

	return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
}

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/**
 * batadv_nc_to_purge_nc_path_coding - checks whether an nc path has timed out
 * @bat_priv: the bat priv with all the soft interface information
 * @nc_path: the nc path to check
 *
 * Returns true if the entry has to be purged now, false otherwise
 */
static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
					      struct batadv_nc_path *nc_path)
{
	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
		return true;

	/* purge the path when no packets has been added for 10 times the
	 * max_fwd_delay time
	 */
	return batadv_has_timed_out(nc_path->last_valid,
				    bat_priv->nc.max_fwd_delay * 10);
}

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/**
 * batadv_nc_to_purge_nc_path_decoding - checks whether an nc path has timed out
 * @bat_priv: the bat priv with all the soft interface information
 * @nc_path: the nc path to check
 *
 * Returns true if the entry has to be purged now, false otherwise
 */
static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
						struct batadv_nc_path *nc_path)
{
	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
		return true;

	/* purge the path when no packets has been added for 10 times the
	 * max_buffer time
	 */
	return batadv_has_timed_out(nc_path->last_valid,
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				    bat_priv->nc.max_buffer_time * 10);
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}

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/**
 * batadv_nc_purge_orig_nc_nodes - go through list of nc nodes and purge stale
 *  entries
 * @bat_priv: the bat priv with all the soft interface information
 * @list: list of nc nodes
 * @lock: nc node list lock
 * @to_purge: function in charge to decide whether an entry has to be purged or
 *	      not. This function takes the nc node as argument and has to return
 *	      a boolean value: true if the entry has to be deleted, false
 *	      otherwise
 */
static void
batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
			      struct list_head *list,
			      spinlock_t *lock,
			      bool (*to_purge)(struct batadv_priv *,
					       struct batadv_nc_node *))
{
	struct batadv_nc_node *nc_node, *nc_node_tmp;

	/* For each nc_node in list */
	spin_lock_bh(lock);
	list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
		/* if an helper function has been passed as parameter,
		 * ask it if the entry has to be purged or not
		 */
		if (to_purge && !to_purge(bat_priv, nc_node))
			continue;

		batadv_dbg(BATADV_DBG_NC, bat_priv,
			   "Removing nc_node %pM -> %pM\n",
			   nc_node->addr, nc_node->orig_node->orig);
		list_del_rcu(&nc_node->list);
		batadv_nc_node_free_ref(nc_node);
	}
	spin_unlock_bh(lock);
}

/**
 * batadv_nc_purge_orig - purges all nc node data attached of the given
 *  originator
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: orig_node with the nc node entries to be purged
 * @to_purge: function in charge to decide whether an entry has to be purged or
 *	      not. This function takes the nc node as argument and has to return
 *	      a boolean value: true is the entry has to be deleted, false
 *	      otherwise
 */
void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
			  struct batadv_orig_node *orig_node,
			  bool (*to_purge)(struct batadv_priv *,
					   struct batadv_nc_node *))
{
	/* Check ingoing nc_node's of this orig_node */
	batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
				      &orig_node->in_coding_list_lock,
				      to_purge);

	/* Check outgoing nc_node's of this orig_node */
	batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
				      &orig_node->out_coding_list_lock,
				      to_purge);
}

/**
 * batadv_nc_purge_orig_hash - traverse entire originator hash to check if they
 *  have timed out nc nodes
 * @bat_priv: the bat priv with all the soft interface information
 */
static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
{
	struct batadv_hashtable *hash = bat_priv->orig_hash;
	struct hlist_head *head;
	struct batadv_orig_node *orig_node;
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	u32 i;
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	if (!hash)
		return;

	/* For each orig_node */
	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(orig_node, head, hash_entry)
			batadv_nc_purge_orig(bat_priv, orig_node,
					     batadv_nc_to_purge_nc_node);
		rcu_read_unlock();
	}
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}

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/**
 * batadv_nc_purge_paths - traverse all nc paths part of the hash and remove
 *  unused ones
 * @bat_priv: the bat priv with all the soft interface information
 * @hash: hash table containing the nc paths to check
 * @to_purge: function in charge to decide whether an entry has to be purged or
 *	      not. This function takes the nc node as argument and has to return
 *	      a boolean value: true is the entry has to be deleted, false
 *	      otherwise
 */
static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
				  struct batadv_hashtable *hash,
				  bool (*to_purge)(struct batadv_priv *,
						   struct batadv_nc_path *))
{
	struct hlist_head *head;
	struct hlist_node *node_tmp;
	struct batadv_nc_path *nc_path;
	spinlock_t *lock; /* Protects lists in hash */
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	u32 i;
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	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];
		lock = &hash->list_locks[i];

		/* For each nc_path in this bin */
		spin_lock_bh(lock);
		hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
			/* if an helper function has been passed as parameter,
			 * ask it if the entry has to be purged or not
			 */
			if (to_purge && !to_purge(bat_priv, nc_path))
				continue;

			/* purging an non-empty nc_path should never happen, but
			 * is observed under high CPU load. Delay the purging
			 * until next iteration to allow the packet_list to be
			 * emptied first.
			 */
			if (!unlikely(list_empty(&nc_path->packet_list))) {
				net_ratelimited_function(printk,
							 KERN_WARNING
							 "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
							 nc_path->prev_hop,
							 nc_path->next_hop);
				continue;
			}

			/* nc_path is unused, so remove it */
			batadv_dbg(BATADV_DBG_NC, bat_priv,
				   "Remove nc_path %pM -> %pM\n",
				   nc_path->prev_hop, nc_path->next_hop);
			hlist_del_rcu(&nc_path->hash_entry);
			batadv_nc_path_free_ref(nc_path);
		}
		spin_unlock_bh(lock);
	}
}

/**
 * batadv_nc_hash_key_gen - computes the nc_path hash key
 * @key: buffer to hold the final hash key
 * @src: source ethernet mac address going into the hash key
 * @dst: destination ethernet mac address going into the hash key
 */
static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
				   const char *dst)
{
	memcpy(key->prev_hop, src, sizeof(key->prev_hop));
	memcpy(key->next_hop, dst, sizeof(key->next_hop));
}

/**
 * batadv_nc_hash_choose - compute the hash value for an nc path
 * @data: data to hash
 * @size: size of the hash table
 *
 * Returns the selected index in the hash table for the given data.
 */
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static u32 batadv_nc_hash_choose(const void *data, u32 size)
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{
	const struct batadv_nc_path *nc_path = data;
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	u32 hash = 0;
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	hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
	hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
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	return hash % size;
}

/**
 * batadv_nc_hash_compare - comparing function used in the network coding hash
 *  tables
 * @node: node in the local table
 * @data2: second object to compare the node to
 *
 * Returns 1 if the two entry are the same, 0 otherwise
 */
static int batadv_nc_hash_compare(const struct hlist_node *node,
				  const void *data2)
{
	const struct batadv_nc_path *nc_path1, *nc_path2;

	nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
	nc_path2 = data2;

	/* Return 1 if the two keys are identical */
	if (memcmp(nc_path1->prev_hop, nc_path2->prev_hop,
		   sizeof(nc_path1->prev_hop)) != 0)
		return 0;

	if (memcmp(nc_path1->next_hop, nc_path2->next_hop,
		   sizeof(nc_path1->next_hop)) != 0)
		return 0;

	return 1;
}

/**
 * batadv_nc_hash_find - search for an existing nc path and return it
 * @hash: hash table containing the nc path
 * @data: search key
 *
 * Returns the nc_path if found, NULL otherwise.
 */
static struct batadv_nc_path *
batadv_nc_hash_find(struct batadv_hashtable *hash,
		    void *data)
{
	struct hlist_head *head;
	struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
	int index;

	if (!hash)
		return NULL;

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

	rcu_read_lock();
	hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
		if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
			continue;

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

		nc_path_tmp = nc_path;
		break;
	}
	rcu_read_unlock();

	return nc_path_tmp;
}

/**
 * batadv_nc_send_packet - send non-coded packet and free nc_packet struct
 * @nc_packet: the nc packet to send
 */
static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
{
	batadv_send_skb_packet(nc_packet->skb,
			       nc_packet->neigh_node->if_incoming,
			       nc_packet->nc_path->next_hop);
	nc_packet->skb = NULL;
	batadv_nc_packet_free(nc_packet);
}

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/**
 * batadv_nc_sniffed_purge - Checks timestamp of given sniffed nc_packet.
 * @bat_priv: the bat priv with all the soft interface information
 * @nc_path: the nc path the packet belongs to
 * @nc_packet: the nc packet to be checked
 *
 * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
 * timeout. If so, the packet is no longer kept and the entry deleted from the
 * queue. Has to be called with the appropriate locks.
 *
 * Returns false as soon as the entry in the fifo queue has not been timed out
 * yet and true otherwise.
 */
static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
				    struct batadv_nc_path *nc_path,
				    struct batadv_nc_packet *nc_packet)
{
	unsigned long timeout = bat_priv->nc.max_buffer_time;
	bool res = false;

587
588
	lockdep_assert_held(&nc_path->packet_list_lock);

589
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	/* Packets are added to tail, so the remaining packets did not time
	 * out and we can stop processing the current queue
	 */
	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
	    !batadv_has_timed_out(nc_packet->timestamp, timeout))
		goto out;

	/* purge nc packet */
	list_del(&nc_packet->list);
	batadv_nc_packet_free(nc_packet);

	res = true;

out:
	return res;
}

606
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616
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621
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624
/**
 * batadv_nc_fwd_flush - Checks the timestamp of the given nc packet.
 * @bat_priv: the bat priv with all the soft interface information
 * @nc_path: the nc path the packet belongs to
 * @nc_packet: the nc packet to be checked
 *
 * Checks whether the given nc packet has hit its forward timeout. If so, the
 * packet is no longer delayed, immediately sent and the entry deleted from the
 * queue. Has to be called with the appropriate locks.
 *
 * Returns false as soon as the entry in the fifo queue has not been timed out
 * yet and true otherwise.
 */
static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
				struct batadv_nc_path *nc_path,
				struct batadv_nc_packet *nc_packet)
{
	unsigned long timeout = bat_priv->nc.max_fwd_delay;

625
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	lockdep_assert_held(&nc_path->packet_list_lock);

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	/* Packets are added to tail, so the remaining packets did not time
	 * out and we can stop processing the current queue
	 */
	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
	    !batadv_has_timed_out(nc_packet->timestamp, timeout))
		return false;

	/* Send packet */
	batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
	batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
			   nc_packet->skb->len + ETH_HLEN);
	list_del(&nc_packet->list);
	batadv_nc_send_packet(nc_packet);

	return true;
}

/**
 * batadv_nc_process_nc_paths - traverse given nc packet pool and free timed out
 *  nc packets
 * @bat_priv: the bat priv with all the soft interface information
 * @hash: to be processed hash table
 * @process_fn: Function called to process given nc packet. Should return true
 *	        to encourage this function to proceed with the next packet.
 *	        Otherwise the rest of the current queue is skipped.
 */
static void
batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
			   struct batadv_hashtable *hash,
			   bool (*process_fn)(struct batadv_priv *,
					      struct batadv_nc_path *,
					      struct batadv_nc_packet *))
{
	struct hlist_head *head;
	struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
	struct batadv_nc_path *nc_path;
	bool ret;
	int i;

	if (!hash)
		return;

	/* Loop hash table bins */
	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		/* Loop coding paths */
		rcu_read_lock();
		hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
			/* Loop packets */
			spin_lock_bh(&nc_path->packet_list_lock);
			list_for_each_entry_safe(nc_packet, nc_packet_tmp,
						 &nc_path->packet_list, list) {
				ret = process_fn(bat_priv, nc_path, nc_packet);
				if (!ret)
					break;
			}
			spin_unlock_bh(&nc_path->packet_list_lock);
		}
		rcu_read_unlock();
	}
}

690
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694
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698
/**
 * batadv_nc_worker - periodic task for house keeping related to network coding
 * @work: kernel work struct
 */
static void batadv_nc_worker(struct work_struct *work)
{
	struct delayed_work *delayed_work;
	struct batadv_priv_nc *priv_nc;
	struct batadv_priv *bat_priv;
699
	unsigned long timeout;
700
701
702
703
704

	delayed_work = container_of(work, struct delayed_work, work);
	priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
	bat_priv = container_of(priv_nc, struct batadv_priv, nc);

705
	batadv_nc_purge_orig_hash(bat_priv);
706
707
	batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
			      batadv_nc_to_purge_nc_path_coding);
708
709
	batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
			      batadv_nc_to_purge_nc_path_decoding);
710
711
712
713
714
715
716
717

	timeout = bat_priv->nc.max_fwd_delay;

	if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
		batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
					   batadv_nc_fwd_flush);
		bat_priv->nc.timestamp_fwd_flush = jiffies;
	}
718

719
720
721
722
723
724
725
	if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
				 bat_priv->nc.max_buffer_time)) {
		batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
					   batadv_nc_sniffed_purge);
		bat_priv->nc.timestamp_sniffed_purge = jiffies;
	}

726
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728
729
	/* Schedule a new check */
	batadv_nc_start_timer(bat_priv);
}

730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
/**
 * batadv_can_nc_with_orig - checks whether the given orig node is suitable for
 *  coding or not
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: neighboring orig node which may be used as nc candidate
 * @ogm_packet: incoming ogm packet also used for the checks
 *
 * Returns true if:
 *  1) The OGM must have the most recent sequence number.
 *  2) The TTL must be decremented by one and only one.
 *  3) The OGM must be received from the first hop from orig_node.
 *  4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
 */
static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
				    struct batadv_orig_node *orig_node,
				    struct batadv_ogm_packet *ogm_packet)
{
747
	struct batadv_orig_ifinfo *orig_ifinfo;
748
749
	u32 last_real_seqno;
	u8 last_ttl;
750
751
752

	orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
	if (!orig_ifinfo)
753
		return false;
754
755
756
757
758
759
760
761

	last_ttl = orig_ifinfo->last_ttl;
	last_real_seqno = orig_ifinfo->last_real_seqno;
	batadv_orig_ifinfo_free_ref(orig_ifinfo);

	if (last_real_seqno != ntohl(ogm_packet->seqno))
		return false;
	if (last_ttl != ogm_packet->ttl + 1)
762
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		return false;
	if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
		return false;
	if (ogm_packet->tq < bat_priv->nc.min_tq)
		return false;

	return true;
}

/**
 * batadv_nc_find_nc_node - search for an existing nc node and return it
 * @orig_node: orig node originating the ogm packet
 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 *  (can be equal to orig_node)
 * @in_coding: traverse incoming or outgoing network coding list
 *
 * Returns the nc_node if found, NULL otherwise.
 */
static struct batadv_nc_node
*batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
			struct batadv_orig_node *orig_neigh_node,
			bool in_coding)
{
	struct batadv_nc_node *nc_node, *nc_node_out = NULL;
	struct list_head *list;

	if (in_coding)
		list = &orig_neigh_node->in_coding_list;
	else
		list = &orig_neigh_node->out_coding_list;

	/* Traverse list of nc_nodes to orig_node */
	rcu_read_lock();
	list_for_each_entry_rcu(nc_node, list, list) {
		if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
			continue;

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

		/* Found a match */
		nc_node_out = nc_node;
		break;
	}
	rcu_read_unlock();

	return nc_node_out;
}

/**
 * batadv_nc_get_nc_node - retrieves an nc node or creates the entry if it was
 *  not found
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: orig node originating the ogm packet
 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 *  (can be equal to orig_node)
 * @in_coding: traverse incoming or outgoing network coding list
 *
 * Returns the nc_node if found or created, NULL in case of an error.
 */
static struct batadv_nc_node
*batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
		       struct batadv_orig_node *orig_node,
		       struct batadv_orig_node *orig_neigh_node,
		       bool in_coding)
{
	struct batadv_nc_node *nc_node;
	spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
	struct list_head *list;

	/* Check if nc_node is already added */
	nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);

	/* Node found */
	if (nc_node)
		return nc_node;

	nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
	if (!nc_node)
		return NULL;

	if (!atomic_inc_not_zero(&orig_neigh_node->refcount))
		goto free;

	/* Initialize nc_node */
	INIT_LIST_HEAD(&nc_node->list);
848
	ether_addr_copy(nc_node->addr, orig_node->orig);
849
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	nc_node->orig_node = orig_neigh_node;
	atomic_set(&nc_node->refcount, 2);

	/* Select ingoing or outgoing coding node */
	if (in_coding) {
		lock = &orig_neigh_node->in_coding_list_lock;
		list = &orig_neigh_node->in_coding_list;
	} else {
		lock = &orig_neigh_node->out_coding_list_lock;
		list = &orig_neigh_node->out_coding_list;
	}

	batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
		   nc_node->addr, nc_node->orig_node->orig);

	/* Add nc_node to orig_node */
	spin_lock_bh(lock);
	list_add_tail_rcu(&nc_node->list, list);
	spin_unlock_bh(lock);

	return nc_node;

free:
	kfree(nc_node);
	return NULL;
}

/**
877
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 * batadv_nc_update_nc_node - updates stored incoming and outgoing nc node
 *  structs (best called on incoming OGMs)
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890
891
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: orig node originating the ogm packet
 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 *  (can be equal to orig_node)
 * @ogm_packet: incoming ogm packet
 * @is_single_hop_neigh: orig_node is a single hop neighbor
 */
void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
			      struct batadv_orig_node *orig_node,
			      struct batadv_orig_node *orig_neigh_node,
			      struct batadv_ogm_packet *ogm_packet,
			      int is_single_hop_neigh)
{
892
893
	struct batadv_nc_node *in_nc_node = NULL;
	struct batadv_nc_node *out_nc_node = NULL;
894
895
896
897
898

	/* Check if network coding is enabled */
	if (!atomic_read(&bat_priv->network_coding))
		goto out;

899
	/* check if orig node is network coding enabled */
900
	if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
901
902
		goto out;

903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
	/* accept ogms from 'good' neighbors and single hop neighbors */
	if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
	    !is_single_hop_neigh)
		goto out;

	/* Add orig_node as in_nc_node on hop */
	in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
					   orig_neigh_node, true);
	if (!in_nc_node)
		goto out;

	in_nc_node->last_seen = jiffies;

	/* Add hop as out_nc_node on orig_node */
	out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
					    orig_node, false);
	if (!out_nc_node)
		goto out;

	out_nc_node->last_seen = jiffies;

out:
	if (in_nc_node)
		batadv_nc_node_free_ref(in_nc_node);
	if (out_nc_node)
		batadv_nc_node_free_ref(out_nc_node);
}

931
932
933
934
935
936
937
938
939
940
941
942
/**
 * batadv_nc_get_path - get existing nc_path or allocate a new one
 * @bat_priv: the bat priv with all the soft interface information
 * @hash: hash table containing the nc path
 * @src: ethernet source address - first half of the nc path search key
 * @dst: ethernet destination address - second half of the nc path search key
 *
 * Returns pointer to nc_path if the path was found or created, returns NULL
 * on error.
 */
static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
						 struct batadv_hashtable *hash,
943
944
						 u8 *src,
						 u8 *dst)
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
{
	int hash_added;
	struct batadv_nc_path *nc_path, nc_path_key;

	batadv_nc_hash_key_gen(&nc_path_key, src, dst);

	/* Search for existing nc_path */
	nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);

	if (nc_path) {
		/* Set timestamp to delay removal of nc_path */
		nc_path->last_valid = jiffies;
		return nc_path;
	}

	/* No existing nc_path was found; create a new */
	nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);

	if (!nc_path)
		return NULL;

	/* Initialize nc_path */
	INIT_LIST_HEAD(&nc_path->packet_list);
	spin_lock_init(&nc_path->packet_list_lock);
	atomic_set(&nc_path->refcount, 2);
	nc_path->last_valid = jiffies;
971
972
	ether_addr_copy(nc_path->next_hop, dst);
	ether_addr_copy(nc_path->prev_hop, src);
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990

	batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
		   nc_path->prev_hop,
		   nc_path->next_hop);

	/* Add nc_path to hash table */
	hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
				     batadv_nc_hash_choose, &nc_path_key,
				     &nc_path->hash_entry);

	if (hash_added < 0) {
		kfree(nc_path);
		return NULL;
	}

	return nc_path;
}

991
992
993
994
995
/**
 * batadv_nc_random_weight_tq - scale the receivers TQ-value to avoid unfair
 *  selection of a receiver with slightly lower TQ than the other
 * @tq: to be weighted tq value
 */
996
static u8 batadv_nc_random_weight_tq(u8 tq)
997
{
998
	u8 rand_val, rand_tq;
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042

	get_random_bytes(&rand_val, sizeof(rand_val));

	/* randomize the estimated packet loss (max TQ - estimated TQ) */
	rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq);

	/* normalize the randomized packet loss */
	rand_tq /= BATADV_TQ_MAX_VALUE;

	/* convert to (randomized) estimated tq again */
	return BATADV_TQ_MAX_VALUE - rand_tq;
}

/**
 * batadv_nc_memxor - XOR destination with source
 * @dst: byte array to XOR into
 * @src: byte array to XOR from
 * @len: length of destination array
 */
static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
{
	unsigned int i;

	for (i = 0; i < len; ++i)
		dst[i] ^= src[i];
}

/**
 * batadv_nc_code_packets - code a received unicast_packet with an nc packet
 *  into a coded_packet and send it
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: data skb to forward
 * @ethhdr: pointer to the ethernet header inside the skb
 * @nc_packet: structure containing the packet to the skb can be coded with
 * @neigh_node: next hop to forward packet to
 *
 * Returns true if both packets are consumed, false otherwise.
 */
static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
				   struct sk_buff *skb,
				   struct ethhdr *ethhdr,
				   struct batadv_nc_packet *nc_packet,
				   struct batadv_neigh_node *neigh_node)
{
1043
	u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1044
1045
1046
1047
1048
1049
	struct sk_buff *skb_dest, *skb_src;
	struct batadv_unicast_packet *packet1;
	struct batadv_unicast_packet *packet2;
	struct batadv_coded_packet *coded_packet;
	struct batadv_neigh_node *neigh_tmp, *router_neigh;
	struct batadv_neigh_node *router_coding = NULL;
1050
1051
	struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
	struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1052
	u8 *first_source, *first_dest, *second_source, *second_dest;
1053
1054
1055
1056
1057
1058
1059
1060
	__be32 packet_id1, packet_id2;
	size_t count;
	bool res = false;
	int coding_len;
	int unicast_size = sizeof(*packet1);
	int coded_size = sizeof(*coded_packet);
	int header_add = coded_size - unicast_size;

1061
1062
1063
1064
1065
	/* TODO: do we need to consider the outgoing interface for
	 * coded packets?
	 */
	router_neigh = batadv_orig_router_get(neigh_node->orig_node,
					      BATADV_IF_DEFAULT);
1066
1067
1068
	if (!router_neigh)
		goto out;

1069
1070
1071
1072
1073
	router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
						      BATADV_IF_DEFAULT);
	if (!router_neigh_ifinfo)
		goto out;

1074
	neigh_tmp = nc_packet->neigh_node;
1075
1076
	router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
					       BATADV_IF_DEFAULT);
1077
1078
1079
	if (!router_coding)
		goto out;

1080
1081
1082
1083
1084
1085
1086
1087
1088
	router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
						       BATADV_IF_DEFAULT);
	if (!router_coding_ifinfo)
		goto out;

	tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
	tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
	tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
	tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
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1131
1132
1133
1134
1135
1136
1137
1138

	/* Select one destination for the MAC-header dst-field based on
	 * weighted TQ-values.
	 */
	if (tq_weighted_neigh >= tq_weighted_coding) {
		/* Destination from nc_packet is selected for MAC-header */
		first_dest = nc_packet->nc_path->next_hop;
		first_source = nc_packet->nc_path->prev_hop;
		second_dest = neigh_node->addr;
		second_source = ethhdr->h_source;
		packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
		packet2 = (struct batadv_unicast_packet *)skb->data;
		packet_id1 = nc_packet->packet_id;
		packet_id2 = batadv_skb_crc32(skb,
					      skb->data + sizeof(*packet2));
	} else {
		/* Destination for skb is selected for MAC-header */
		first_dest = neigh_node->addr;
		first_source = ethhdr->h_source;
		second_dest = nc_packet->nc_path->next_hop;
		second_source = nc_packet->nc_path->prev_hop;
		packet1 = (struct batadv_unicast_packet *)skb->data;
		packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
		packet_id1 = batadv_skb_crc32(skb,
					      skb->data + sizeof(*packet1));
		packet_id2 = nc_packet->packet_id;
	}

	/* Instead of zero padding the smallest data buffer, we
	 * code into the largest.
	 */
	if (skb->len <= nc_packet->skb->len) {
		skb_dest = nc_packet->skb;
		skb_src = skb;
	} else {
		skb_dest = skb;
		skb_src = nc_packet->skb;
	}

	/* coding_len is used when decoding the packet shorter packet */
	coding_len = skb_src->len - unicast_size;

	if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
		goto out;

	skb_push(skb_dest, header_add);

	coded_packet = (struct batadv_coded_packet *)skb_dest->data;
	skb_reset_mac_header(skb_dest);

1139
1140
1141
	coded_packet->packet_type = BATADV_CODED;
	coded_packet->version = BATADV_COMPAT_VERSION;
	coded_packet->ttl = packet1->ttl;
1142
1143

	/* Info about first unicast packet */
1144
1145
	ether_addr_copy(coded_packet->first_source, first_source);
	ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1146
1147
1148
1149
	coded_packet->first_crc = packet_id1;
	coded_packet->first_ttvn = packet1->ttvn;

	/* Info about second unicast packet */
1150
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1152
	ether_addr_copy(coded_packet->second_dest, second_dest);
	ether_addr_copy(coded_packet->second_source, second_source);
	ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1153
	coded_packet->second_crc = packet_id2;
1154
	coded_packet->second_ttl = packet2->ttl;
1155
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	coded_packet->second_ttvn = packet2->ttvn;
	coded_packet->coded_len = htons(coding_len);

	/* This is where the magic happens: Code skb_src into skb_dest */
	batadv_nc_memxor(skb_dest->data + coded_size,
			 skb_src->data + unicast_size, coding_len);

	/* Update counters accordingly */
	if (BATADV_SKB_CB(skb_src)->decoded &&
	    BATADV_SKB_CB(skb_dest)->decoded) {
		/* Both packets are recoded */
		count = skb_src->len + ETH_HLEN;
		count += skb_dest->len + ETH_HLEN;
		batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
		batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
	} else if (!BATADV_SKB_CB(skb_src)->decoded &&
		   !BATADV_SKB_CB(skb_dest)->decoded) {
		/* Both packets are newly coded */
		count = skb_src->len + ETH_HLEN;
		count += skb_dest->len + ETH_HLEN;
		batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
		batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
	} else if (BATADV_SKB_CB(skb_src)->decoded &&
		   !BATADV_SKB_CB(skb_dest)->decoded) {
		/* skb_src recoded and skb_dest is newly coded */
		batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
		batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
				   skb_src->len + ETH_HLEN);
		batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
		batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
				   skb_dest->len + ETH_HLEN);
	} else if (!BATADV_SKB_CB(skb_src)->decoded &&
		   BATADV_SKB_CB(skb_dest)->decoded) {
		/* skb_src is newly coded and skb_dest is recoded */
		batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
		batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
				   skb_src->len + ETH_HLEN);
		batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
		batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
				   skb_dest->len + ETH_HLEN);
	}

	/* skb_src is now coded into skb_dest, so free it */
	kfree_skb(skb_src);

	/* avoid duplicate free of skb from nc_packet */
	nc_packet->skb = NULL;
	batadv_nc_packet_free(nc_packet);

	/* Send the coded packet and return true */
	batadv_send_skb_packet(skb_dest, neigh_node->if_incoming, first_dest);
	res = true;
out:
	if (router_neigh)
		batadv_neigh_node_free_ref(router_neigh);
	if (router_coding)
		batadv_neigh_node_free_ref(router_coding);
1212
1213
1214
1215
	if (router_neigh_ifinfo)
		batadv_neigh_ifinfo_free_ref(router_neigh_ifinfo);
	if (router_coding_ifinfo)
		batadv_neigh_ifinfo_free_ref(router_coding_ifinfo);
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
	return res;
}

/**
 * batadv_nc_skb_coding_possible - true if a decoded skb is available at dst.
 * @skb: data skb to forward
 * @dst: destination mac address of the other skb to code with
 * @src: source mac address of skb
 *
 * Whenever we network code a packet we have to check whether we received it in
 * a network coded form. If so, we may not be able to use it for coding because
 * some neighbors may also have received (overheard) the packet in the network
 * coded form without being able to decode it. It is hard to know which of the
 * neighboring nodes was able to decode the packet, therefore we can only
 * re-code the packet if the source of the previous encoded packet is involved.
 * Since the source encoded the packet we can be certain it has all necessary
 * decode information.
 *
 * Returns true if coding of a decoded packet is allowed.
 */
1236
static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1237
1238
1239
{
	if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
		return false;
1240
	return true;
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
}

/**
 * batadv_nc_path_search - Find the coding path matching in_nc_node and
 *  out_nc_node to retrieve a buffered packet that can be used for coding.
 * @bat_priv: the bat priv with all the soft interface information
 * @in_nc_node: pointer to skb next hop's neighbor nc node
 * @out_nc_node: pointer to skb source's neighbor nc node
 * @skb: data skb to forward
 * @eth_dst: next hop mac address of skb
 *
 * Returns true if coding of a decoded skb is allowed.
 */
static struct batadv_nc_packet *
batadv_nc_path_search(struct batadv_priv *bat_priv,
		      struct batadv_nc_node *in_nc_node,
		      struct batadv_nc_node *out_nc_node,
		      struct sk_buff *skb,
1259
		      u8 *eth_dst)
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
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1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
{
	struct batadv_nc_path *nc_path, nc_path_key;
	struct batadv_nc_packet *nc_packet_out = NULL;
	struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
	struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
	int idx;

	if (!hash)
		return NULL;

	/* Create almost path key */
	batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
			       out_nc_node->addr);
	idx = batadv_nc_hash_choose(&nc_path_key, hash->size);

	/* Check for coding opportunities in this nc_path */
	rcu_read_lock();
	hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
		if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
			continue;

		if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
			continue;

		spin_lock_bh(&nc_path->packet_list_lock);
		if (list_empty(&nc_path->packet_list)) {
			spin_unlock_bh(&nc_path->packet_list_lock);
			continue;
		}

		list_for_each_entry_safe(nc_packet, nc_packet_tmp,
					 &nc_path->packet_list, list) {
			if (!batadv_nc_skb_coding_possible(nc_packet->skb,
							   eth_dst,
							   in_nc_node->addr))
				continue;

			/* Coding opportunity is found! */
			list_del(&nc_packet->list);
			nc_packet_out = nc_packet;
			break;
		}

		spin_unlock_bh(&nc_path->packet_list_lock);
		break;
	}
	rcu_read_unlock();

	return nc_packet_out;
}

/**
 * batadv_nc_skb_src_search - Loops through the list of neighoring nodes of the
 *  skb's sender (may be equal to the originator).
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: data skb to forward
 * @eth_dst: next hop mac address of skb
 * @eth_src: source mac address of skb
 * @in_nc_node: pointer to skb next hop's neighbor nc node
 *
 * Returns an nc packet if a suitable coding packet was found, NULL otherwise.
 */
static struct batadv_nc_packet *
batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
			 struct sk_buff *skb,
1325
1326
			 u8 *eth_dst,
			 u8 *eth_src,
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
			 struct batadv_nc_node *in_nc_node)
{
	struct batadv_orig_node *orig_node;
	struct batadv_nc_node *out_nc_node;
	struct batadv_nc_packet *nc_packet = NULL;

	orig_node = batadv_orig_hash_find(bat_priv, eth_src);
	if (!orig_node)
		return NULL;

	rcu_read_lock();
	list_for_each_entry_rcu(out_nc_node,
				&orig_node->out_coding_list, list) {
		/* Check if the skb is decoded and if recoding is possible */
		if (!batadv_nc_skb_coding_possible(skb,
						   out_nc_node->addr, eth_src))
			continue;

		/* Search for an opportunity in this nc_path */
		nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
						  out_nc_node, skb, eth_dst);
		if (nc_packet)
			break;
	}
	rcu_read_unlock();

	batadv_orig_node_free_ref(orig_node);
	return nc_packet;
}

1357
1358
1359
1360
1361
1362
1363
1364
1365
/**
 * batadv_nc_skb_store_before_coding - set the ethernet src and dst of the
 *  unicast skb before it is stored for use in later decoding
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: data skb to store
 * @eth_dst_new: new destination mac address of skb
 */
static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
					      struct sk_buff *skb,
1366
					      u8 *eth_dst_new)
1367
1368
1369
1370
{
	struct ethhdr *ethhdr;

	/* Copy skb header to change the mac header */
1371
	skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1372
1373
1374
1375
	if (!skb)
		return;

	/* Set the mac header as if we actually sent the packet uncoded */
1376
	ethhdr = eth_hdr(skb);
1377
1378
	ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
	ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391

	/* Set data pointer to MAC header to mimic packets from our tx path */
	skb_push(skb, ETH_HLEN);

	/* Add the packet to the decoding packet pool */
	batadv_nc_skb_store_for_decoding(bat_priv, skb);

	/* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
	 * our ref
	 */
	kfree_skb(skb);
}

1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
/**
 * batadv_nc_skb_dst_search - Loops through list of neighboring nodes to dst.
 * @skb: data skb to forward
 * @neigh_node: next hop to forward packet to
 * @ethhdr: pointer to the ethernet header inside the skb
 *
 * Loops through list of neighboring nodes the next hop has a good connection to
 * (receives OGMs with a sufficient quality). We need to find a neighbor of our
 * next hop that potentially sent a packet which our next hop also received
 * (overheard) and has stored for later decoding.
 *
 * Returns true if the skb was consumed (encoded packet sent) or false otherwise
 */
static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
				     struct batadv_neigh_node *neigh_node,
				     struct ethhdr *ethhdr)
{
	struct net_device *netdev = neigh_node->if_incoming->soft_iface;
	struct batadv_priv *bat_priv = netdev_priv(netdev);
	struct batadv_orig_node *orig_node = neigh_node->orig_node;
	struct batadv_nc_node *nc_node;
	struct batadv_nc_packet *nc_packet = NULL;

	rcu_read_lock();
	list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
		/* Search for coding opportunity with this in_nc_node */
		nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
						     neigh_node->addr,
						     ethhdr->h_source, nc_node);

		/* Opportunity was found, so stop searching */
		if (nc_packet)
			break;
	}
	rcu_read_unlock();

	if (!nc_packet)
		return false;

1431
1432
1433
1434
1435
1436
	/* Save packets for later decoding */
	batadv_nc_skb_store_before_coding(bat_priv, skb,
					  neigh_node->addr);
	batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
					  nc_packet->neigh_node->addr);

1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
	/* Code and send packets */
	if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
				   neigh_node))
		return true;

	/* out of mem ? Coding failed - we have to free the buffered packet
	 * to avoid memleaks. The skb passed as argument will be dealt with
	 * by the calling function.
	 */
	batadv_nc_send_packet(nc_packet);
	return false;
}

1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
/**
 * batadv_nc_skb_add_to_path - buffer skb for later encoding / decoding
 * @skb: skb to add to path
 * @nc_path: path to add skb to
 * @neigh_node: next hop to forward packet to
 * @packet_id: checksum to identify packet
 *
 * Returns true if the packet was buffered or false in case of an error.
 */
static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
				      struct batadv_nc_path *nc_path,
				      struct batadv_neigh_node *neigh_node,
				      __be32 packet_id)
{
	struct batadv_nc_packet *nc_packet;

	nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
	if (!nc_packet)
		return false;

	/* Initialize nc_packet */
	nc_packet->timestamp = jiffies;
	nc_packet->packet_id = packet_id;
	nc_packet->skb = skb;
	nc_packet->neigh_node = neigh_node;
	nc_packet->nc_path = nc_path;

	/* Add coding packet to list */
	spin_lock_bh(&nc_path->packet_list_lock);
	list_add_tail(&nc_packet->list, &nc_path->packet_list);
	spin_unlock_bh(&nc_path->packet_list_lock);

	return true;
}

/**
 * batadv_nc_skb_forward - try to code a packet or add it to the coding packet
 *  buffer
 * @skb: data skb to forward
 * @neigh_node: next hop to forward packet to
 *
 * Returns true if the skb was consumed (encoded packet sent) or false otherwise
 */
bool batadv_nc_skb_forward(struct sk_buff *skb,
1494
			   struct batadv_neigh_node *neigh_node)
1495
1496
1497
1498
1499
{
	const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
	struct batadv_priv *bat_priv = netdev_priv(netdev);
	struct batadv_unicast_packet *packet;
	struct batadv_nc_path *nc_path;
1500
	struct ethhdr *ethhdr = eth_hdr(skb);
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
	__be32 packet_id;
	u8 *payload;

	/* Check if network coding is enabled */
	if (!atomic_read(&bat_priv->network_coding))
		goto out;

	/* We only handle unicast packets */
	payload = skb_network_header(skb);
	packet = (struct batadv_unicast_packet *)payload;
1511
	if (packet->packet_type != BATADV_UNICAST)
1512
1513
		goto out;

1514
1515
1516
1517
	/* Try to find a coding opportunity and send the skb if one is found */
	if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
		return true;

1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
	/* Find or create a nc_path for this src-dst pair */
	nc_path = batadv_nc_get_path(bat_priv,
				     bat_priv->nc.coding_hash,
				     ethhdr->h_source,
				     neigh_node->addr);

	if (!nc_path)
		goto out;

	/* Add skb to nc_path */
	packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
	if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
		goto free_nc_path;

	/* Packet is consumed */
	return true;

free_nc_path:
	batadv_nc_path_free_ref(nc_path);
out:
	/* Packet is not consumed */
	return false;
}

1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
/**
 * batadv_nc_skb_store_for_decoding - save a clone of the skb which can be used
 *  when decoding coded packets
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: data skb to store
 */
void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
				      struct sk_buff *skb)
{
	struct batadv_unicast_packet *packet;
	struct batadv_nc_path *nc_path;
1553
	struct ethhdr *ethhdr = eth_hdr(skb);
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
	__be32 packet_id;
	u8 *payload;

	/* Check if network coding is enabled */
	if (!atomic_read(&bat_priv->network_coding))
		goto out;

	/* Check for supported packet type */
	payload = skb_network_header(skb);
	packet = (struct batadv_unicast_packet *)payload;
1564
	if (packet->packet_type != BATADV_UNICAST)
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
		goto out;

	/* Find existing nc_path or create a new */
	nc_path = batadv_nc_get_path(bat_priv,
				     bat_priv->nc.decoding_hash,
				     ethhdr->h_source,
				     ethhdr->h_dest);

	if (!nc_path)
		goto out;

	/* Clone skb and adjust skb->data to point at batman header */
	skb = skb_clone(skb, GFP_ATOMIC);
	if (unlikely(!skb))
		goto free_nc_path;

	if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
		goto free_skb;

	if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
		goto free_skb;

	/* Add skb to nc_path */
	packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
	if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
		goto free_skb;

	batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
	return;

free_skb:
	kfree_skb(skb);
free_nc_path:
	batadv_nc_path_free_ref(nc_path);
out:
	return;
}

/**
 * batadv_nc_skb_store_sniffed_unicast - check if a received unicast packet
 *  should be saved in the decoding buffer and, if so, store it there
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: unicast skb to store
 */
void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
					 struct sk_buff *skb)
{
1612
	struct ethhdr *ethhdr = eth_hdr(skb);
1613

1614
	if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1615
1616
1617
1618
1619
1620
1621
1622
		return;

	/* Set data pointer to MAC header to mimic packets from our tx path */
	skb_push(skb, ETH_HLEN);

	batadv_nc_skb_store_for_decoding(bat_priv, skb);
}

1623
1624
1625
/**
 * batadv_nc_skb_decode_packet - decode given skb using the decode data stored
 *  in nc_packet
1626
 * @bat_priv: the bat priv with all the soft interface information
1627
1628
1629
1630
1631
1632
1633
 * @skb: unicast skb to decode
 * @nc_packet: decode data needed to decode the skb
 *
 * Returns pointer to decoded unicast packet if the packet was decoded or NULL
 * in case of an error.
 */
static struct batadv_unicast_packet *
1634
batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1635
1636
1637
1638
1639
1640
1641
			    struct batadv_nc_packet *nc_packet)
{
	const int h_size = sizeof(struct batadv_unicast_packet);
	const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
	struct batadv_unicast_packet *unicast_packet;
	struct batadv_coded_packet coded_packet_tmp;
	struct ethhdr *ethhdr, ethhdr_tmp;
1642
	u8 *orig_dest, ttl, ttvn;
1643
	unsigned int coding_len;
1644
	int err;
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662

	/* Save headers temporarily */
	memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
	memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));

	if (skb_cow(skb, 0) < 0)
		return NULL;

	if (unlikely(!skb_pull_rcsum(skb, h_diff)))
		return NULL;

	/* Data points to batman header, so set mac header 14 bytes before
	 * and network to data
	 */
	skb_set_mac_header(skb, -ETH_HLEN);
	skb_reset_network_header(skb);

	/* Reconstruct original mac header */
1663
	ethhdr = eth_hdr(skb);
1664
	*ethhdr = ethhdr_tmp;
1665
1666
1667
1668

	/* Select the correct unicast header information based on the location
	 * of our mac address in the coded_packet header
	 */
1669
	if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1670
1671
1672
1673
		/* If we are the second destination the packet was overheard,
		 * so the Ethernet address must be copied to h_dest and
		 * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
		 */
1674
		ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1675
1676
1677
1678
1679
1680
1681
		skb->pkt_type = PACKET_HOST;

		orig_dest = coded_packet_tmp.second_orig_dest;
		ttl = coded_packet_tmp.second_ttl;
		ttvn = coded_packet_tmp.second_ttvn;
	} else {
		orig_dest = coded_packet_tmp.first_orig_dest;
1682
		ttl = coded_packet_tmp.ttl;
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
		ttvn = coded_packet_tmp.first_ttvn;
	}

	coding_len = ntohs(coded_packet_tmp.coded_len);

	if (coding_len > skb->len)
		return NULL;

	/* Here the magic is reversed:
	 *   extract the missing packet from the received coded packet
	 */
	batadv_nc_memxor(skb->data + h_size,
			 nc_packet->skb->data + h_size,
			 coding_len);

	/* Resize decoded skb if decoded with larger packet */
1699
1700
1701
1702
1703
	if (nc_packet->skb->len > coding_len + h_size) {
		err = pskb_trim_rcsum(skb, coding_len + h_size);
		if (err)
			return NULL;
	}
1704
1705
1706

	/* Create decoded unicast packet */
	unicast_packet = (struct batadv_unicast_packet *)skb->data;
1707
1708
1709
	unicast_packet->packet_type = BATADV_UNICAST;
	unicast_packet->version = BATADV_COMPAT_VERSION;
	unicast_packet->ttl = ttl;
1710
	ether_addr_copy(unicast_packet->dest, orig_dest);
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
	unicast_packet->ttvn = ttvn;

	batadv_nc_packet_free(nc_packet);
	return unicast_packet;
}

/**
 * batadv_nc_find_decoding_packet - search through buffered decoding data to
 *  find the data needed to decode the coded packet
 * @bat_priv: the bat priv with all the soft interface information
 * @ethhdr: pointer to the ethernet header inside the coded packet
 * @coded: coded packet we try to find decode data for
 *
 * Returns pointer to nc packet if the needed data was found or NULL otherwise.
 */
static struct batadv_nc_packet *
batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
			       struct ethhdr *ethhdr,
			       struct batadv_coded_packet *coded)
{
	struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
	struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
	struct batadv_nc_path *nc_path, nc_path_key;
1734
	u8 *dest, *source;
1735
1736
1737
1738
1739
1740
1741
1742
	__be32 packet_id;
	int index;

	if (!hash)
		return NULL;

	/* Select the correct packet id based on the location of our mac-addr */
	dest = ethhdr->h_source;
1743
	if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
		source = coded->second_source;
		packet_id = coded->second_crc;
	} else {
		source = coded->first_source;
		packet_id = coded->first_crc;
	}

	batadv_nc_hash_key_gen(&nc_path_key, source, dest);
	index = batadv_nc_hash_choose(&nc_path_key, hash->size);

	/* Search for matching coding path */
	rcu_read_lock();
	hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
		/* Find matching nc_packet */
		spin_lock_bh(&nc_path->packet_list_lock);
		list_for_each_entry(tmp_nc_packet,
				    &nc_path->packet_list, list) {
			if (packet_id == tmp_nc_packet->packet_id) {
				list_del(&tmp_nc_packet->list);

				nc_packet = tmp_nc_packet;
				break;
			}
		}
		spin_unlock_bh(&nc_path->packet_list_lock);

		if (nc_packet)
			break;
	}
	rcu_read_unlock();

	if (!nc_packet)
		batadv_dbg(BATADV_DBG_NC, bat_priv,
			   "No decoding packet found for %u\n", packet_id);

	return nc_packet;
}

/**
 * batadv_nc_recv_coded_packet - try to decode coded packet and enqueue the
 *  resulting unicast packet
 * @skb: incoming coded packet
 * @recv_if: pointer to interface this packet was received on
 */
static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
				       struct batadv_hard_iface *recv_if)
{
	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
	struct batadv_unicast_packet *unicast_packet;
	struct batadv_coded_packet *coded_packet;
	struct batadv_nc_packet *nc_packet;
	struct ethhdr *ethhdr;
	int hdr_size = sizeof(*coded_packet);

	/* Check if network coding is enabled */
	if (!atomic_read(&bat_priv->network_coding))
		return NET_RX_DROP;

	/* Make sure we can access (and remove) header */
	if (unlikely(!pskb_may_pull(skb, hdr_size)))
		return NET_RX_DROP;

	coded_packet = (struct batadv_coded_packet *)skb->data;
1807
	ethhdr = eth_hdr(skb);
1808
1809

	/* Verify frame is destined for us */
1810
1811
	if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
	    !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1812
1813
1814
		return NET_RX_DROP;

	/* Update stat counter */
1815
	if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
		batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);

	nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
						   coded_packet);
	if (!nc_packet) {
		batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
		return NET_RX_DROP;
	}

	/* Make skb's linear, because decoding accesses the entire buffer */
	if (skb_linearize(skb) < 0)
		goto free_nc_packet;

	if (skb_linearize(nc_packet->skb) < 0)
		goto free_nc_packet;

	/* Decode the packet */
1833
	unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
	if (!unicast_packet) {
		batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
		goto free_nc_packet;
	}

	/* Mark packet as decoded to do correct recoding when forwarding */
	BATADV_SKB_CB(skb)->decoded = true;
	batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
	batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
			   skb->len + ETH_HLEN);
	return batadv_recv_unicast_packet(skb, recv_if);

free_nc_packet:
	batadv_nc_packet_free(nc_packet);
	return NET_RX_DROP;
}

1851
/**
1852
 * batadv_nc_mesh_free - clean up network coding memory
1853
1854
 * @bat_priv: the bat priv with all the soft interface information
 */
1855
void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1856
{
1857
1858
	batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
	batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1859
	cancel_delayed_work_sync(&bat_priv->nc.work);
1860

1861
1862
	batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
	batadv_hash_destroy(bat_priv->nc.coding_hash);
1863
1864
	batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
	batadv_hash_destroy(bat_priv->nc.decoding_hash);
1865
}
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893

/**
 * batadv_nc_nodes_seq_print_text - print the nc node information
 * @seq: seq file to print on
 * @offset: not used
 */
int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
{
	struct net_device *net_dev = (struct net_device *)seq->private;
	struct batadv_priv *bat_priv = netdev_priv(net_dev);
	struct batadv_hashtable *hash = bat_priv->orig_hash;
	struct batadv_hard_iface *primary_if;
	struct hlist_head *head;
	struct batadv_orig_node *orig_node;
	struct batadv_nc_node *nc_node;
	int i;

	primary_if = batadv_seq_print_text_primary_if_get(seq);
	if (!primary_if)
		goto out;

	/* Traverse list of originators */
	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		/* For each orig_node in this bin */
		rcu_read_lock();
		hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1894
1895
1896
1897
1898
1899
1900
			/* no need to print the orig node if it does not have
			 * network coding neighbors
			 */
			if (list_empty(&orig_node->in_coding_list) &&
			    list_empty(&orig_node->out_coding_list))
				continue;

1901
1902
			seq_printf(seq, "Node:      %pM\n", orig_node->orig);

1903
			seq_puts(seq, " Ingoing:  ");
1904
1905
1906
1907
1908
1909
			/* For each in_nc_node to this orig_node */
			list_for_each_entry_rcu(nc_node,
						&orig_node->in_coding_list,
						list)
				seq_printf(seq, "%pM ",
					   nc_node->addr);
1910
			seq_puts(seq, "\n");
1911

1912
			seq_puts(seq, " Outgoing: ");
1913
1914
1915
1916
1917
1918
			/* For out_nc_node to this orig_node */
			list_for_each_entry_rcu(nc_node,
						&orig_node->out_coding_list,
						list)
				seq_printf(seq, "%pM ",
					   nc_node->addr);