| /* 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_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); |
| |
| 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; |
| |
| /* 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; |
| 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_weighted_neigh = batadv_nc_random_weight_tq(router_neigh->tq_avg); |
| tq_weighted_coding = batadv_nc_random_weight_tq(router_coding->tq_avg); |
| |
| /* 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 = (struct ethhdr *)skb_mac_header(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 |
| * @ethhdr: pointer to the ethernet header inside the skb |
| * |
| * 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, |
| struct ethhdr *ethhdr) |
| { |
| 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; |
| __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 = (struct ethhdr *)skb_mac_header(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 = (struct ethhdr *)skb_mac_header(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 = (struct ethhdr *)skb_mac_header(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 = (struct ethhdr *)skb_mac_header(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) |
| { |
| 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) { |
| 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; |
| } |