--- /dev/null
+/* Copyright (C) 2012-2014 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#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.decoding_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)
+{
+ struct batadv_orig_ifinfo *orig_ifinfo;
+ uint32_t last_real_seqno;
+ uint8_t last_ttl;
+
+ orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
+ if (!orig_ifinfo)
+ return false;
+
+ 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)
+ 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);
+ ether_addr_copy(nc_node->addr, orig_node->orig);
+ 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;
+ ether_addr_copy(nc_path->next_hop, dst);
+ ether_addr_copy(nc_path->prev_hop, src);
+
+ 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;
+ struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
+ struct batadv_neigh_ifinfo *router_coding_ifinfo = 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;
+
+ /* 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);
+ if (!router_neigh)
+ goto out;
+
+ router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
+ BATADV_IF_DEFAULT);
+ if (!router_neigh_ifinfo)
+ goto out;
+
+ neigh_tmp = nc_packet->neigh_node;
+ router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
+ BATADV_IF_DEFAULT);
+ if (!router_coding)
+ goto out;
+
+ 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);
+
+ /* 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->packet_type = BATADV_CODED;
+ coded_packet->version = BATADV_COMPAT_VERSION;
+ coded_packet->ttl = packet1->ttl;
+
+ /* Info about first unicast packet */
+ ether_addr_copy(coded_packet->first_source, first_source);
+ ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
+ coded_packet->first_crc = packet_id1;
+ coded_packet->first_ttvn = packet1->ttvn;
+
+ /* Info about second unicast packet */
+ 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);
+ coded_packet->second_crc = packet_id2;
+ coded_packet->second_ttl = packet2->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);
+ if (router_neigh_ifinfo)
+ batadv_neigh_ifinfo_free_ref(router_neigh_ifinfo);
+ if (router_coding_ifinfo)
+ batadv_neigh_ifinfo_free_ref(router_coding_ifinfo);
+ 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;
+ 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_for_clone(skb, GFP_ATOMIC);
+ if (!skb)
+ return;
+
+ /* Set the mac header as if we actually sent the packet uncoded */
+ ethhdr = eth_hdr(skb);
+ ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
+ ether_addr_copy(ethhdr->h_dest, eth_dst_new);
+
+ /* 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->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->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);
+ *ethhdr = ethhdr_tmp;
+
+ /* 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
+ */
+ ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
+ 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.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->packet_type = BATADV_UNICAST;
+ unicast_packet->version = BATADV_COMPAT_VERSION;
+ unicast_packet->ttl = ttl;
+ ether_addr_copy(unicast_packet->dest, orig_dest);
+ 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;
+}
Code Review / kvmfornfv.git / blobdiff