// 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * batadv_nc_mesh_init() - initialise coding hash table and start housekeeping * @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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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 *)) { … } /** * 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 *)) { … } /** * 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) { … } /** * 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 *)) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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_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) { … } /** * 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) { … } /** * 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 *)) { … } /** * batadv_nc_worker() - periodic task for housekeeping related to network * coding * @work: kernel work struct */ static void batadv_nc_worker(struct work_struct *work) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … }
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