diff options
Diffstat (limited to 'net/batman-adv/network-coding.c')
| -rw-r--r-- | net/batman-adv/network-coding.c | 1878 |
1 files changed, 0 insertions, 1878 deletions
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c deleted file mode 100644 index af97d077369f..000000000000 --- a/net/batman-adv/network-coding.c +++ /dev/null @@ -1,1878 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* Copyright (C) B.A.T.M.A.N. contributors: - * - * Martin Hundebøll, Jeppe Ledet-Pedersen - */ - -#include "network-coding.h" -#include "main.h" - -#include <linux/atomic.h> -#include <linux/bitops.h> -#include <linux/byteorder/generic.h> -#include <linux/compiler.h> -#include <linux/container_of.h> -#include <linux/errno.h> -#include <linux/etherdevice.h> -#include <linux/gfp.h> -#include <linux/if_ether.h> -#include <linux/if_packet.h> -#include <linux/init.h> -#include <linux/jhash.h> -#include <linux/jiffies.h> -#include <linux/kref.h> -#include <linux/list.h> -#include <linux/lockdep.h> -#include <linux/net.h> -#include <linux/netdevice.h> -#include <linux/printk.h> -#include <linux/random.h> -#include <linux/rculist.h> -#include <linux/rcupdate.h> -#include <linux/skbuff.h> -#include <linux/slab.h> -#include <linux/spinlock.h> -#include <linux/stddef.h> -#include <linux/string.h> -#include <linux/workqueue.h> -#include <uapi/linux/batadv_packet.h> - -#include "hash.h" -#include "log.h" -#include "originator.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) -{ - /* Register our packet type */ - return batadv_recv_handler_register(BATADV_CODED, - batadv_nc_recv_coded_packet); -} - -/** - * batadv_nc_start_timer() - initialise the nc periodic worker - * @bat_priv: the bat priv with all the mesh 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 mesh 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 mesh 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 mesh 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 housekeeping - * @bat_priv: the bat priv with all the mesh 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) { - batadv_hash_destroy(bat_priv->nc.coding_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, 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 mesh 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) -{ - if (!nc_node) - return; - - 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) -{ - if (!nc_path) - return; - - kref_put(&nc_path->refcount, batadv_nc_path_release); -} - -/** - * batadv_nc_packet_free() - frees nc packet - * @nc_packet: the nc packet to free - * @dropped: whether the packet is freed because is dropped - */ -static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet, - bool dropped) -{ - if (dropped) - kfree_skb(nc_packet->skb); - else - consume_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 mesh 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 mesh 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 mesh 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 mesh 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 mesh 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 mesh 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 mesh 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, false); -} - -/** - * batadv_nc_sniffed_purge() - Checks timestamp of given sniffed nc_packet. - * @bat_priv: the bat priv with all the mesh 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, true); - - 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 mesh 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 mesh 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 housekeeping 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 mesh 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 mesh 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; - - /* 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; - } - - spin_lock_bh(lock); - - /* 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) - goto unlock; - - nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC); - if (!nc_node) - goto unlock; - - /* Initialize nc_node */ - INIT_LIST_HEAD(&nc_node->list); - kref_init(&nc_node->refcount); - ether_addr_copy(nc_node->addr, orig_node->orig); - kref_get(&orig_neigh_node->refcount); - nc_node->orig_node = orig_neigh_node; - - 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 */ - kref_get(&nc_node->refcount); - list_add_tail_rcu(&nc_node->list, list); - -unlock: - 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 mesh 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: - batadv_nc_node_put(in_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 mesh 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); - 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 */ - kref_get(&nc_path->refcount); - 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) -{ - /* randomize the estimated packet loss (max TQ - estimated TQ) */ - u8 rand_tq = get_random_u32_below(BATADV_TQ_MAX_VALUE + 1 - tq); - - /* 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 mesh 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 */ - consume_skb(skb_src); - - /* avoid duplicate free of skb from nc_packet */ - nc_packet->skb = NULL; - batadv_nc_packet_free(nc_packet, false); - - /* Send the coded packet and return true */ - batadv_send_unicast_skb(skb_dest, first_dest); - res = true; -out: - batadv_neigh_node_put(router_neigh); - batadv_neigh_node_put(router_coding); - batadv_neigh_ifinfo_put(router_neigh_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 mesh 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 neighboring nodes of - * the skb's sender (may be equal to the originator). - * @bat_priv: the bat priv with all the mesh 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 mesh 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 - */ - consume_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 the 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->mesh_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->mesh_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 mesh 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 mesh 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 mesh 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); - - /* ensure dst buffer is large enough (payload only) */ - if (coding_len + h_size > skb->len) - return NULL; - - /* ensure src buffer is large enough (payload only) */ - if (coding_len + h_size > nc_packet->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, false); - 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 mesh 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->mesh_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)) - goto free_skb; - - /* Make sure we can access (and remove) header */ - if (unlikely(!pskb_may_pull(skb, hdr_size))) - goto free_skb; - - 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)) - goto free_skb; - - /* 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); - goto free_skb; - } - - /* 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, true); -free_skb: - kfree_skb(skb); - - return NET_RX_DROP; -} - -/** - * batadv_nc_mesh_free() - clean up network coding memory - * @bat_priv: the bat priv with all the mesh 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); -} |