/* Copyright (C) 2012-2016 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 . */ #include "network-coding.h" #include "main.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "hard-interface.h" #include "hash.h" #include "log.h" #include "originator.h" #include "packet.h" #include "routing.h" #include "send.h" #include "tvlv.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 * * Return: 0 on success or negative error number in case of failure */ 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, u8 flags, void *tvlv_value, u16 tvlv_value_len) { if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND) clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities); else set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities); } /** * batadv_nc_mesh_init - initialise coding hash table and start house keeping * @bat_priv: the bat priv with all the soft interface information * * Return: 0 on success or negative error number in case of failure */ 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, 0); 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_release - release nc_node from lists and queue for free after * rcu grace period * @ref: kref pointer of the nc_node */ static void batadv_nc_node_release(struct kref *ref) { struct batadv_nc_node *nc_node; nc_node = container_of(ref, struct batadv_nc_node, refcount); batadv_orig_node_put(nc_node->orig_node); kfree_rcu(nc_node, rcu); } /** * batadv_nc_node_put - decrement the nc_node refcounter and possibly * release it * @nc_node: nc_node to be free'd */ static void batadv_nc_node_put(struct batadv_nc_node *nc_node) { kref_put(&nc_node->refcount, batadv_nc_node_release); } /** * batadv_nc_path_release - release nc_path from lists and queue for free after * rcu grace period * @ref: kref pointer of the nc_path */ static void batadv_nc_path_release(struct kref *ref) { struct batadv_nc_path *nc_path; nc_path = container_of(ref, struct batadv_nc_path, refcount); kfree_rcu(nc_path, rcu); } /** * batadv_nc_path_put - decrement the nc_path refcounter and possibly * release it * @nc_path: nc_path to be free'd */ static void batadv_nc_path_put(struct batadv_nc_path *nc_path) { kref_put(&nc_path->refcount, batadv_nc_path_release); } /** * 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) { kfree_skb(nc_packet->skb); batadv_nc_path_put(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 * * Return: 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 * * Return: 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 * * Return: 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_put(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; u32 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 */ u32 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_put(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 * * Return: the selected index in the hash table for the given data. */ static u32 batadv_nc_hash_choose(const void *data, u32 size) { const struct batadv_nc_path *nc_path = data; u32 hash = 0; hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash); hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash); 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 * * Return: true if the two entry are the same, false otherwise */ static bool 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 (!batadv_compare_eth(nc_path1->prev_hop, nc_path2->prev_hop)) return false; if (!batadv_compare_eth(nc_path1->next_hop, nc_path2->next_hop)) return false; return true; } /** * batadv_nc_hash_find - search for an existing nc path and return it * @hash: hash table containing the nc path * @data: search key * * Return: 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 (!kref_get_unless_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_unicast_skb(nc_packet->skb, nc_packet->neigh_node); 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. * * Return: 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; lockdep_assert_held(&nc_path->packet_list_lock); /* 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. * * Return: 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; lockdep_assert_held(&nc_path->packet_list_lock); /* 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 = to_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 * * Return: 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; u32 last_real_seqno; u8 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_put(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 * * Return: 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 (!kref_get_unless_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 * * Return: 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; kref_get(&orig_neigh_node->refcount); /* 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; kref_init(&nc_node->refcount); kref_get(&nc_node->refcount); /* 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; } /** * 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; struct batadv_nc_node *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 (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities)) 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_put(in_nc_node); if (out_nc_node) batadv_nc_node_put(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 * * Return: 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, u8 *src, u8 *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); kref_init(&nc_path->refcount); kref_get(&nc_path->refcount); 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 * * Return: scaled tq value */ static u8 batadv_nc_random_weight_tq(u8 tq) { u8 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 * * Return: 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) { u8 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, *first_dest; struct batadv_neigh_node *router_coding = NULL, *second_dest; struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL; struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL; u8 *first_source, *second_source; __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->neigh_node; first_source = nc_packet->nc_path->prev_hop; second_dest = neigh_node; 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; first_source = ethhdr->h_source; second_dest = nc_packet->neigh_node; 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->addr); 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_unicast_skb(skb_dest, first_dest); res = true; out: if (router_neigh) batadv_neigh_node_put(router_neigh); if (router_coding) batadv_neigh_node_put(router_coding); if (router_neigh_ifinfo) batadv_neigh_ifinfo_put(router_neigh_ifinfo); if (router_coding_ifinfo) batadv_neigh_ifinfo_put(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. * * Return: true if coding of a decoded packet is allowed. */ static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *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 * * Return: 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, u8 *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 * * Return: 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, u8 *eth_dst, u8 *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_put(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, u8 *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. * * Return: 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 * * Return: 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 * * Return: 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_put(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_put(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 * * Return: 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; u8 *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 * * Return: 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; u8 *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 * * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP * otherwise. */ 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 * * Return: always 0 */ 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_put(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 * * Return: 0 on success or negative error number in case of failure */ 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; }