/* Copyright (C) 2012-2013 B.A.T.M.A.N. contributors:
*
* 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
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*/
#include <linux/debugfs.h>
#include "main.h"
#include "hash.h"
#include "network-coding.h"
#include "send.h"
#include "originator.h"
#include "hard-interface.h"
#include "routing.h"
static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
static void batadv_nc_worker(struct work_struct *work);
static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if);
/**
* 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;
}
/**
* 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));
}
/**
* 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);
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,
uint8_t flags,
void *tvlv_value,
uint16_t tvlv_value_len)
{
if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_NC;
else
orig->capabilities |= BATADV_ORIG_CAPA_HAS_NC;
}
/**
* batadv_nc_mesh_init - initialise coding hash table and start house keeping
* @bat_priv: the bat priv with all the soft interface information
*/
int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
{
bat_priv->nc.timestamp_fwd_flush = jiffies;
bat_priv->nc.timestamp_sniffed_purge = jiffies;
if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
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);
bat_priv->nc.decoding_hash = batadv_hash_new(128);
if (!bat_priv->nc.decoding_hash)
goto err;
batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
&batadv_nc_decoding_hash_lock_class_key);
INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
batadv_nc_start_timer(bat_priv);
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);
return 0;
err:
return -ENOMEM;
}
/**
* 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)
{
atomic_set(&bat_priv->network_coding, 1);
bat_priv->nc.min_tq = 200;
bat_priv->nc.max_fwd_delay = 10;
bat_priv->nc.max_buffer_time = 200;
}
/**
* 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);
}
/**
* 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)
{
if (nc_packet->skb)
kfree_skb(nc_packet->skb);
batadv_nc_path_free_ref(nc_packet->nc_path);
kfree(nc_packet);
}
/**
* 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);
}
/**
* 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);
}
/**
* 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,
bat_priv->nc.max_buffer_time*10);
}
/**
* 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;
uint32_t i;
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();
}
}
/**
* 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 */
uint32_t i;
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.
*/
static uint32_t batadv_nc_hash_choose(const void *data, uint32_t size)
{
const struct batadv_nc_path *nc_path = data;
uint32_t hash = 0;
hash = batadv_hash_bytes(hash, &nc_path->prev_hop,
sizeof(nc_path->prev_hop));
hash = batadv_hash_bytes(hash, &nc_path->next_hop,
sizeof(nc_path->next_hop));
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
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);
}
/**
* 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;
/* 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;
}
/**
* 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;
/* 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();
}
}
/**
* 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;
unsigned long timeout;
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);
batadv_nc_purge_orig_hash(bat_priv);
batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
batadv_nc_to_purge_nc_path_coding);
batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
batadv_nc_to_purge_nc_path_decoding);
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;
}
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;
}
/* Schedule a new check */
batadv_nc_start_timer(bat_priv);
}
/**
* 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)
{
if (orig_node->last_real_seqno != ntohl(ogm_packet->seqno))
return false;
if (orig_node->last_ttl != ogm_packet->header.ttl + 1)
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);
memcpy(nc_node->addr, orig_node->orig, ETH_ALEN);
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;
}
/**
* batadv_nc_update_nc_node - updates stored incoming and outgoing nc node structs
* (best called on incoming OGMs)
* @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)
{
struct batadv_nc_node *in_nc_node = NULL, *out_nc_node = NULL;
/* Check if network coding is enabled */
if (!atomic_read(&bat_priv->network_coding))
goto out;
/* check if orig node is network coding enabled */
if (!(orig_node->capabilities & BATADV_ORIG_CAPA_HAS_NC))
goto out;
/* 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);
}
/**
* 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,
uint8_t *src,
uint8_t *dst)
{
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;
memcpy(nc_path->next_hop, dst, ETH_ALEN);
memcpy(nc_path->prev_hop, src, ETH_ALEN);
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;
}
/**
* 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
*/
static uint8_t batadv_nc_random_weight_tq(uint8_t tq)
{
uint8_t rand_val, rand_tq;
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)
{
uint8_t tq_weighted_neigh, tq_weighted_coding, tq_tmp;
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;
uint8_t *first_source, *first_dest, *second_source, *second_dest;
__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;
router_neigh = batadv_orig_node_get_router(neigh_node->orig_node);
if (!router_neigh)
goto out;
neigh_tmp = nc_packet->neigh_node;
router_coding = batadv_orig_node_get_router(neigh_tmp->orig_node);
if (!router_coding)
goto out;
tq_tmp = batadv_nc_random_weight_tq(router_neigh->bat_iv.tq_avg);
tq_weighted_neigh = tq_tmp;
tq_tmp = batadv_nc_random_weight_tq(router_coding->bat_iv.tq_avg);
tq_weighted_coding = tq_tmp;
/* 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);
coded_packet->header.packet_type = BATADV_CODED;
coded_packet->header.version = BATADV_COMPAT_VERSION;
coded_packet->header.ttl = packet1->header.ttl;
/* Info about first unicast packet */
memcpy(coded_packet->first_source, first_source, ETH_ALEN);
memcpy(coded_packet->first_orig_dest, packet1->dest, ETH_ALEN);
coded_packet->first_crc = packet_id1;
coded_packet->first_ttvn = packet1->ttvn;
/* Info about second unicast packet */
memcpy(coded_packet->second_dest, second_dest, ETH_ALEN);
memcpy(coded_packet->second_source, second_source, ETH_ALEN);
memcpy(coded_packet->second_orig_dest, packet2->dest, ETH_ALEN);
coded_packet->second_crc = packet_id2;
coded_packet->second_ttl = packet2->header.ttl;
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);
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.
*/
static bool batadv_nc_skb_coding_possible(struct sk_buff *skb,
uint8_t *dst, uint8_t *src)
{
if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
return false;
else
return true;
}
/**
* 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,
uint8_t *eth_dst)
{
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,
uint8_t *eth_dst,
uint8_t *eth_src,
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;
}
/**
* 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,
uint8_t *eth_dst_new)
{
struct ethhdr *ethhdr;
/* Copy skb header to change the mac header */
skb = pskb_copy(skb, GFP_ATOMIC);
if (!skb)
return;
/* Set the mac header as if we actually sent the packet uncoded */
ethhdr = eth_hdr(skb);
memcpy(ethhdr->h_source, ethhdr->h_dest, ETH_ALEN);
memcpy(ethhdr->h_dest, eth_dst_new, ETH_ALEN);
/* 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);
}
/**
* 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;
/* 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);
/* 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;
}
/**
* 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,
struct batadv_neigh_node *neigh_node)
{
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;
struct ethhdr *ethhdr = eth_hdr(skb);
__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;
if (packet->header.packet_type != BATADV_UNICAST)
goto out;
/* 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;
/* 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;
}
/**
* 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;
struct ethhdr *ethhdr = eth_hdr(skb);
__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;
if (packet->header.packet_type != BATADV_UNICAST)
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)
{
struct ethhdr *ethhdr = eth_hdr(skb);
if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
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);
}
/**
* batadv_nc_skb_decode_packet - decode given skb using the decode data stored
* in nc_packet
* @bat_priv: the bat priv with all the soft interface information
* @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 *
batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
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;
uint8_t *orig_dest, ttl, ttvn;
unsigned int coding_len;
int err;
/* Save headers temporarily */
memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
memcpy(ðhdr_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 */
ethhdr = eth_hdr(skb);
memcpy(ethhdr, ðhdr_tmp, sizeof(*ethhdr));
/* Select the correct unicast header information based on the location
* of our mac address in the coded_packet header
*/
if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
/* 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
*/
memcpy(ethhdr->h_dest, coded_packet_tmp.second_dest, ETH_ALEN);
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;
ttl = coded_packet_tmp.header.ttl;
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 */
if (nc_packet->skb->len > coding_len + h_size) {
err = pskb_trim_rcsum(skb, coding_len + h_size);
if (err)
return NULL;
}
/* Create decoded unicast packet */
unicast_packet = (struct batadv_unicast_packet *)skb->data;
unicast_packet->header.packet_type = BATADV_UNICAST;
unicast_packet->header.version = BATADV_COMPAT_VERSION;
unicast_packet->header.ttl = ttl;
memcpy(unicast_packet->dest, orig_dest, ETH_ALEN);
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;
uint8_t *dest, *source;
__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;
if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
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;
ethhdr = eth_hdr(skb);
/* Verify frame is destined for us */
if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
!batadv_is_my_mac(bat_priv, coded_packet->second_dest))
return NET_RX_DROP;
/* Update stat counter */
if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
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 */
unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
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;
}
/**
* batadv_nc_mesh_free - clean up network coding memory
* @bat_priv: the bat priv with all the soft interface information
*/
void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
{
batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
cancel_delayed_work_sync(&bat_priv->nc.work);
batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
batadv_hash_destroy(bat_priv->nc.coding_hash);
batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
batadv_hash_destroy(bat_priv->nc.decoding_hash);
}
/**
* 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) {
/* 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;
seq_printf(seq, "Node: %pM\n", orig_node->orig);
seq_puts(seq, " Ingoing: ");
/* 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);
seq_puts(seq, "\n");
seq_puts(seq, " Outgoing: ");
/* 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);
seq_puts(seq, "\n\n");
}
rcu_read_unlock();
}
out:
if (primary_if)
batadv_hardif_free_ref(primary_if);
return 0;
}
/**
* batadv_nc_init_debugfs - create nc folder and related files in debugfs
* @bat_priv: the bat priv with all the soft interface information
*/
int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
{
struct dentry *nc_dir, *file;
nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
if (!nc_dir)
goto out;
file = debugfs_create_u8("min_tq", S_IRUGO | S_IWUSR, nc_dir,
&bat_priv->nc.min_tq);
if (!file)
goto out;
file = debugfs_create_u32("max_fwd_delay", S_IRUGO | S_IWUSR, nc_dir,
&bat_priv->nc.max_fwd_delay);
if (!file)
goto out;
file = debugfs_create_u32("max_buffer_time", S_IRUGO | S_IWUSR, nc_dir,
&bat_priv->nc.max_buffer_time);
if (!file)
goto out;
return 0;
out:
return -ENOMEM;
}
