To use network coding efficiently, a relay must know when neighbor nodes are likely to have enough information to be able to decode a network coded packet. This is detected by using OGMs from batman-adv to discover when one neighbor is in range of another neighbor. The relay check the TLL to detect when an OGM is forwarded from one neighbor by another neighbor, and thereby knows that the two neighbors are in range and thus overhear packets sent by each other.

This information is saved in the orig_node struct to be used when searching for coding opportunities. Two lists are added to the orig_node struct: One for neighbors that can hear the orig_node (outgoing nc_nodes) and one for neighbors that the orig_node can hear (incoming nc_nodes).

Information about nc_nodes is kept for 10 seconds and is available through debugfs in batman_adv/nc_nodes to use when debugging network coding.

Signed-off-by: Martin Hundebøll martin@hundeboll.net --- v3: * Fixed typos in kernel doc v4: * Added missing kernel doc entry for struct batadv_priv_nc

bat_iv_ogm.c | 5 + debugfs.c | 18 +++ main.h | 2 + network-coding.c | 416 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ network-coding.h | 47 +++++++ originator.c | 6 + types.h | 32 +++++ 7 files changed, 526 insertions(+)

diff --git a/bat_iv_ogm.c b/bat_iv_ogm.c index 72fe1bb..7654b76 100644 --- a/bat_iv_ogm.c +++ b/bat_iv_ogm.c @@ -27,6 +27,7 @@ #include "hard-interface.h" #include "send.h" #include "bat_algo.h" +#include "network-coding.h"

static struct batadv_neigh_node * batadv_iv_ogm_neigh_new(struct batadv_hard_iface *hard_iface, @@ -1189,6 +1190,10 @@ static void batadv_iv_ogm_process(const struct ethhdr *ethhdr, if (!orig_neigh_node) goto out;

+ /* Update nc_nodes of the originator */ + batadv_nc_update_nc_node(bat_priv, orig_node, orig_neigh_node, + batadv_ogm_packet, is_single_hop_neigh); + orig_neigh_router = batadv_orig_node_get_router(orig_neigh_node);

/* drop packet if sender is not a direct neighbor and if we diff --git a/debugfs.c b/debugfs.c index 6ae8651..f186a55 100644 --- a/debugfs.c +++ b/debugfs.c @@ -32,6 +32,7 @@ #include "icmp_socket.h" #include "bridge_loop_avoidance.h" #include "distributed-arp-table.h" +#include "network-coding.h"

static struct dentry *batadv_debugfs;

@@ -310,6 +311,14 @@ struct batadv_debuginfo { const struct file_operations fops; };

+#ifdef CONFIG_BATMAN_ADV_NC +static int batadv_nc_nodes_open(struct inode *inode, struct file *file) +{ + struct net_device *net_dev = (struct net_device *)inode->i_private; + return single_open(file, batadv_nc_nodes_seq_print_text, net_dev); +} +#endif + #define BATADV_DEBUGINFO(_name, _mode, _open) \ struct batadv_debuginfo batadv_debuginfo_##_name = { \ .attr = { .name = __stringify(_name), \ @@ -348,6 +357,9 @@ static BATADV_DEBUGINFO(dat_cache, S_IRUGO, batadv_dat_cache_open); static BATADV_DEBUGINFO(transtable_local, S_IRUGO, batadv_transtable_local_open); static BATADV_DEBUGINFO(vis_data, S_IRUGO, batadv_vis_data_open); +#ifdef CONFIG_BATMAN_ADV_NC +static BATADV_DEBUGINFO(nc_nodes, S_IRUGO, batadv_nc_nodes_open); +#endif

static struct batadv_debuginfo *batadv_mesh_debuginfos[] = { &batadv_debuginfo_originators, @@ -362,6 +374,9 @@ static struct batadv_debuginfo *batadv_mesh_debuginfos[] = { #endif &batadv_debuginfo_transtable_local, &batadv_debuginfo_vis_data, +#ifdef CONFIG_BATMAN_ADV_NC + &batadv_debuginfo_nc_nodes, +#endif NULL, };

@@ -431,6 +446,9 @@ int batadv_debugfs_add_meshif(struct net_device *dev) } }

+ if (batadv_nc_init_debugfs(bat_priv) < 0) + goto rem_attr; + return 0; rem_attr: debugfs_remove_recursive(bat_priv->debug_dir); diff --git a/main.h b/main.h index bf70aed..4e81d93 100644 --- a/main.h +++ b/main.h @@ -105,6 +105,8 @@ #define BATADV_RESET_PROTECTION_MS 30000 #define BATADV_EXPECTED_SEQNO_RANGE 65536

+#define BATADV_NC_NODE_TIMEOUT 10000 /* Milliseconds */ + enum batadv_mesh_state { BATADV_MESH_INACTIVE, BATADV_MESH_ACTIVE, diff --git a/network-coding.c b/network-coding.c index 9c2d54b..0be0c75 100644 --- a/network-coding.c +++ b/network-coding.c @@ -17,8 +17,12 @@ * 02110-1301, USA */

+#include <linux/debugfs.h> + #include "main.h" #include "network-coding.h" +#include "originator.h" +#include "hard-interface.h"

static void batadv_nc_worker(struct work_struct *work);

@@ -51,6 +55,152 @@ int batadv_nc_init(struct batadv_priv *bat_priv) void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv) { atomic_set(&bat_priv->network_coding, 1); + bat_priv->nc.min_tq = 200; +} + +/** + * batadv_nc_init_orig - initialise the nc fields of an orig_node + * @orig_node: the orig_node which is going to be initialised + */ +void batadv_nc_init_orig(struct batadv_orig_node *orig_node) +{ + INIT_LIST_HEAD(&orig_node->in_coding_list); + INIT_LIST_HEAD(&orig_node->out_coding_list); + spin_lock_init(&orig_node->in_coding_list_lock); + spin_lock_init(&orig_node->out_coding_list_lock); +} + +/** + * batadv_nc_node_free_rcu - rcu callback to free an nc node and remove + * its refcount on the orig_node + * @rcu: rcu pointer of the nc node + */ +static void batadv_nc_node_free_rcu(struct rcu_head *rcu) +{ + struct batadv_nc_node *nc_node; + + nc_node = container_of(rcu, struct batadv_nc_node, rcu); + batadv_orig_node_free_ref(nc_node->orig_node); + kfree(nc_node); +} + +/** + * batadv_nc_node_free_ref - decrements the nc node refcounter and possibly + * frees it + * @nc_node: the nc node to free + */ +static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node) +{ + if (atomic_dec_and_test(&nc_node->refcount)) + call_rcu(&nc_node->rcu, batadv_nc_node_free_rcu); +} + +/** + * batadv_nc_to_purge_nc_node - checks whether an nc node has to be purged + * @bat_priv: the bat priv with all the soft interface information + * @nc_node: the nc node to check + * + * Returns true if the entry has to be purged now, false otherwise + */ +static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv, + struct batadv_nc_node *nc_node) +{ + if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE) + return true; + + return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT); +} + +/** + * batadv_nc_purge_orig_nc_nodes - go through list of nc nodes and purge stale + * entries + * @bat_priv: the bat priv with all the soft interface information + * @list: list of nc nodes + * @lock: nc node list lock + * @to_purge: function in charge to decide whether an entry has to be purged or + * not. This function takes the nc node as argument and has to return + * a boolean value: true if the entry has to be deleted, false + * otherwise + */ +static void +batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv, + struct list_head *list, + spinlock_t *lock, + bool (*to_purge)(struct batadv_priv *, + struct batadv_nc_node *)) +{ + struct batadv_nc_node *nc_node, *nc_node_tmp; + + /* For each nc_node in list */ + spin_lock_bh(lock); + list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) { + /* if an helper function has been passed as parameter, + * ask it if the entry has to be purged or not + */ + if (to_purge && !to_purge(bat_priv, nc_node)) + continue; + + batadv_dbg(BATADV_DBG_NC, bat_priv, + "Removing nc_node %pM -> %pM\n", + nc_node->addr, nc_node->orig_node->orig); + list_del_rcu(&nc_node->list); + batadv_nc_node_free_ref(nc_node); + } + spin_unlock_bh(lock); +} + +/** + * batadv_nc_purge_orig - purges all nc node data attached of the given + * originator + * @bat_priv: the bat priv with all the soft interface information + * @orig_node: orig_node with the nc node entries to be purged + * @to_purge: function in charge to decide whether an entry has to be purged or + * not. This function takes the nc node as argument and has to return + * a boolean value: true is the entry has to be deleted, false + * otherwise + */ +void batadv_nc_purge_orig(struct batadv_priv *bat_priv, + struct batadv_orig_node *orig_node, + bool (*to_purge)(struct batadv_priv *, + struct batadv_nc_node *)) +{ + /* Check ingoing nc_node's of this orig_node */ + batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list, + &orig_node->in_coding_list_lock, + to_purge); + + /* Check outgoing nc_node's of this orig_node */ + batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list, + &orig_node->out_coding_list_lock, + to_purge); +} + +/** + * batadv_nc_purge_orig_hash - traverse entire originator hash to check if they + * have timed out nc nodes + * @bat_priv: the bat priv with all the soft interface information + */ +static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv) +{ + struct batadv_hashtable *hash = bat_priv->orig_hash; + struct hlist_node *node; + struct hlist_head *head; + struct batadv_orig_node *orig_node; + uint32_t i; + + if (!hash) + return; + + /* For each orig_node */ + for (i = 0; i < hash->size; i++) { + head = &hash->table[i]; + + rcu_read_lock(); + hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) + batadv_nc_purge_orig(bat_priv, orig_node, + batadv_nc_to_purge_nc_node); + rcu_read_unlock(); + } }

/** @@ -67,11 +217,197 @@ static void batadv_nc_worker(struct work_struct *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); + /* Schedule a new check */ batadv_nc_start_timer(bat_priv); }

/** + * batadv_can_nc_with_orig - checks whether the given orig node is suitable for + * coding or not + * @bat_priv: the bat priv with all the soft interface information + * @orig_node: neighboring orig node which may be used as nc candidate + * @ogm_packet: incoming ogm packet also used for the checks + * + * Returns true if: + * 1) The OGM must have the most recent sequence number. + * 2) The TTL must be decremented by one and only one. + * 3) The OGM must be received from the first hop from orig_node. + * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq. + */ +static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv, + struct batadv_orig_node *orig_node, + struct batadv_ogm_packet *ogm_packet) +{ + if (orig_node->last_real_seqno != ogm_packet->seqno) + return false; + if (orig_node->last_ttl != ogm_packet->header.ttl + 1) + return false; + if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender)) + return false; + if (ogm_packet->tq < bat_priv->nc.min_tq) + return false; + + return true; +} + +/** + * batadv_nc_find_nc_node - search for an existing nc node and return it + * @orig_node: orig node originating the ogm packet + * @orig_neigh_node: neighboring orig node from which we received the ogm packet + * (can be equal to orig_node) + * @in_coding: traverse incoming or outgoing network coding list + * + * Returns the nc_node if found, NULL otherwise. + */ +static struct batadv_nc_node +*batadv_nc_find_nc_node(struct batadv_orig_node *orig_node, + struct batadv_orig_node *orig_neigh_node, + bool in_coding) +{ + struct batadv_nc_node *nc_node, *nc_node_out = NULL; + struct list_head *list; + + if (in_coding) + list = &orig_neigh_node->in_coding_list; + else + list = &orig_neigh_node->out_coding_list; + + /* Traverse list of nc_nodes to orig_node */ + rcu_read_lock(); + list_for_each_entry_rcu(nc_node, list, list) { + if (!batadv_compare_eth(nc_node->addr, orig_node->orig)) + continue; + + if (!atomic_inc_not_zero(&nc_node->refcount)) + continue; + + /* Found a match */ + nc_node_out = nc_node; + break; + } + rcu_read_unlock(); + + return nc_node_out; +} + +/** + * batadv_nc_get_nc_node - retrieves an nc node or creates the entry if it was + * not found + * @bat_priv: the bat priv with all the soft interface information + * @orig_node: orig node originating the ogm packet + * @orig_neigh_node: neighboring orig node from which we received the ogm packet + * (can be equal to orig_node) + * @in_coding: traverse incoming or outgoing network coding list + * + * Returns the nc_node if found or created, NULL in case of an error. + */ +static struct batadv_nc_node +*batadv_nc_get_nc_node(struct batadv_priv *bat_priv, + struct batadv_orig_node *orig_node, + struct batadv_orig_node *orig_neigh_node, + bool in_coding) +{ + struct batadv_nc_node *nc_node; + spinlock_t *lock; /* Used to lock list selected by "int in_coding" */ + struct list_head *list; + + /* Check if nc_node is already added */ + nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding); + + /* Node found */ + if (nc_node) + return nc_node; + + nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC); + if (!nc_node) + return NULL; + + if (!atomic_inc_not_zero(&orig_neigh_node->refcount)) + goto free; + + /* Initialize nc_node */ + INIT_LIST_HEAD(&nc_node->list); + memcpy(nc_node->addr, orig_node->orig, ETH_ALEN); + nc_node->orig_node = orig_neigh_node; + atomic_set(&nc_node->refcount, 2); + + /* Select ingoing or outgoing coding node */ + if (in_coding) { + lock = &orig_neigh_node->in_coding_list_lock; + list = &orig_neigh_node->in_coding_list; + } else { + lock = &orig_neigh_node->out_coding_list_lock; + list = &orig_neigh_node->out_coding_list; + } + + batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n", + nc_node->addr, nc_node->orig_node->orig); + + /* Add nc_node to orig_node */ + spin_lock_bh(lock); + list_add_tail_rcu(&nc_node->list, list); + spin_unlock_bh(lock); + + return nc_node; + +free: + kfree(nc_node); + return NULL; +} + +/** + * batadv_nc_update_nc_node - updates stored incoming and outgoing nc node structs + * (best called on incoming OGMs) + * @bat_priv: the bat priv with all the soft interface information + * @orig_node: orig node originating the ogm packet + * @orig_neigh_node: neighboring orig node from which we received the ogm packet + * (can be equal to orig_node) + * @ogm_packet: incoming ogm packet + * @is_single_hop_neigh: orig_node is a single hop neighbor + */ +void batadv_nc_update_nc_node(struct batadv_priv *bat_priv, + struct batadv_orig_node *orig_node, + struct batadv_orig_node *orig_neigh_node, + struct batadv_ogm_packet *ogm_packet, + int is_single_hop_neigh) +{ + struct batadv_nc_node *in_nc_node = NULL, *out_nc_node = NULL; + + /* Check if network coding is enabled */ + if (!atomic_read(&bat_priv->network_coding)) + goto out; + + /* accept ogms from 'good' neighbors and single hop neighbors */ + if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) && + !is_single_hop_neigh) + goto out; + + /* Add orig_node as in_nc_node on hop */ + in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node, + orig_neigh_node, true); + if (!in_nc_node) + goto out; + + in_nc_node->last_seen = jiffies; + + /* Add hop as out_nc_node on orig_node */ + out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node, + orig_node, false); + if (!out_nc_node) + goto out; + + out_nc_node->last_seen = jiffies; + +out: + if (in_nc_node) + batadv_nc_node_free_ref(in_nc_node); + if (out_nc_node) + batadv_nc_node_free_ref(out_nc_node); +} + +/** * batadv_nc_free - clean up network coding memory * @bat_priv: the bat priv with all the soft interface information */ @@ -79,3 +415,83 @@ void batadv_nc_free(struct batadv_priv *bat_priv) { cancel_delayed_work_sync(&bat_priv->nc.work); } + +/** + * batadv_nc_nodes_seq_print_text - print the nc node information + * @seq: seq file to print on + * @offset: not used + */ +int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset) +{ + struct net_device *net_dev = (struct net_device *)seq->private; + struct batadv_priv *bat_priv = netdev_priv(net_dev); + struct batadv_hashtable *hash = bat_priv->orig_hash; + struct batadv_hard_iface *primary_if; + struct hlist_node *node; + 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, node, head, hash_entry) { + seq_printf(seq, "Node: %pM\n", orig_node->orig); + + seq_printf(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_printf(seq, "\n"); + + seq_printf(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_printf(seq, "\n\n"); + } + rcu_read_unlock(); + } + +out: + if (primary_if) + batadv_hardif_free_ref(primary_if); + return 0; +} + +/** + * batadv_nc_init_debugfs - create nc folder and related files in debugfs + * @bat_priv: the bat priv with all the soft interface information + */ +int batadv_nc_init_debugfs(struct batadv_priv *bat_priv) +{ + struct dentry *nc_dir, *file; + + nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir); + if (!nc_dir) + goto out; + + file = debugfs_create_u8("min_tq", S_IRUGO | S_IWUSR, nc_dir, + &bat_priv->nc.min_tq); + if (!file) + goto out; + + return 0; + +out: + return -ENOMEM; +} diff --git a/network-coding.h b/network-coding.h index 8ee4046..55e5a7b 100644 --- a/network-coding.h +++ b/network-coding.h @@ -24,7 +24,19 @@

int batadv_nc_init(struct batadv_priv *bat_priv); void batadv_nc_free(struct batadv_priv *bat_priv); +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); +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 *)); void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv); +void batadv_nc_init_orig(struct batadv_orig_node *orig_node); +int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset); +int batadv_nc_init_debugfs(struct batadv_priv *bat_priv);

#else /* ifdef CONFIG_BATMAN_ADV_NC */

@@ -38,11 +50,46 @@ static inline void batadv_nc_free(struct batadv_priv *bat_priv) return; }

+static inline 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) +{ + return; +} + +static inline 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 *)) +{ + return; +} + static inline void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv) { return; }

+static inline void batadv_nc_init_orig(struct batadv_orig_node *orig_node) +{ + return; +} + +static inline int batadv_nc_nodes_seq_print_text(struct seq_file *seq, + void *offset) +{ + return 0; +} + +static inline int batadv_nc_init_debugfs(struct batadv_priv *bat_priv) +{ + return 0; +} + #endif /* ifdef CONFIG_BATMAN_ADV_NC */

#endif /* _NET_BATMAN_ADV_NETWORK_CODING_H */ diff --git a/originator.c b/originator.c index 457ea44..9bedd50 100644 --- a/originator.c +++ b/originator.c @@ -28,6 +28,7 @@ #include "unicast.h" #include "soft-interface.h" #include "bridge_loop_avoidance.h" +#include "network-coding.h"

/* hash class keys */ static struct lock_class_key batadv_orig_hash_lock_class_key; @@ -142,6 +143,9 @@ static void batadv_orig_node_free_rcu(struct rcu_head *rcu)

spin_unlock_bh(&orig_node->neigh_list_lock);

+ /* Free nc_nodes */ + batadv_nc_purge_orig(orig_node->bat_priv, orig_node, NULL); + batadv_frag_list_free(&orig_node->frag_list); batadv_tt_global_del_orig(orig_node->bat_priv, orig_node, "originator timed out"); @@ -219,6 +223,8 @@ struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv, spin_lock_init(&orig_node->neigh_list_lock); spin_lock_init(&orig_node->tt_buff_lock);

+ batadv_nc_init_orig(orig_node); + /* extra reference for return */ atomic_set(&orig_node->refcount, 2);

diff --git a/types.h b/types.h index 20de752..f759f33 100644 --- a/types.h +++ b/types.h @@ -128,6 +128,10 @@ struct batadv_hard_iface { * @bond_list: list of bonding candidates * @refcount: number of contexts the object is used * @rcu: struct used for freeing in an RCU-safe manner + * @in_coding_list: list of nodes this orig can hear + * @out_coding_list: list of nodes that can hear this orig + * @in_coding_list_lock: protects in_coding_list + * @out_coding_list_lock: protects out_coding_list */ struct batadv_orig_node { uint8_t orig[ETH_ALEN]; @@ -171,6 +175,12 @@ struct batadv_orig_node { struct list_head bond_list; atomic_t refcount; struct rcu_head rcu; +#ifdef CONFIG_BATMAN_ADV_NC + struct list_head in_coding_list; + struct list_head out_coding_list; + spinlock_t in_coding_list_lock; /* Protects in_coding_list */ + spinlock_t out_coding_list_lock; /* Protects out_coding_list */ +#endif };

/** @@ -430,9 +440,13 @@ struct batadv_priv_dat { /** * struct batadv_priv_nc - per mesh interface network coding private data * @work: work queue callback item for cleanup + * @debug_dir: dentry for nc subdir in batman-adv directory in debugfs + * @min_tq: only consider neighbors for encoding if neigh_tq > min_tq */ struct batadv_priv_nc { struct delayed_work work; + struct dentry *debug_dir; + u8 min_tq; };

/** @@ -716,6 +730,24 @@ struct batadv_tt_roam_node { };

/** + * struct batadv_nc_node - network coding node + * @list: next and prev pointer for the list handling + * @addr: the node's mac address + * @refcount: number of contexts the object is used by + * @rcu: struct used for freeing in an RCU-safe manner + * @orig_node: pointer to corresponding orig node struct + * @last_seen: timestamp of last ogm received from this node + */ +struct batadv_nc_node { + struct list_head list; + uint8_t addr[ETH_ALEN]; + atomic_t refcount; + struct rcu_head rcu; + struct batadv_orig_node *orig_node; + unsigned long last_seen; +}; + +/** * struct batadv_forw_packet - structure for bcast packets to be sent/forwarded * @list: list node for batadv_socket_client::queue_list * @send_time: execution time for delayed_work (packet sending)

Before adding forward-skbs to the coding buffer, the buffer is searched for a potential coding opportunity. If one is found, the two packets are network coded and transmitted right away. If not, the forward-skb is added to the buffer.

Network coded packets are transmitted with information about the two receivers and the two coded packets. The first receiver is given by the MAC header, while the second is given in the payload/bat-header. The second receiver uses promiscuous mode to receive the packet and check the second destination.

Signed-off-by: Martin Hundebøll martin@hundeboll.net --- v3: * Fix header-diff in batadv_nc_code_packets() v4: * Add missing kernel doc entry for enum batadv_counters

main.h | 6 + network-coding.c | 403 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ packet.h | 33 +++++ soft-interface.c | 6 + types.h | 20 +++ 5 files changed, 468 insertions(+)

diff --git a/main.h b/main.h index 4e81d93..8a9caa0 100644 --- a/main.h +++ b/main.h @@ -304,4 +304,10 @@ static inline uint64_t batadv_sum_counter(struct batadv_priv *bat_priv, return sum; }

+/* Define a macro to reach the control buffer of the skb. The members of the + * control buffer are defined in struct batadv_skb_cb in types.h. + * The macro is inspired by the similar macro TCP_SKB_CB() in tcp.h. + */ +#define BATADV_SKB_CB(__skb) ((struct batadv_skb_cb *)&((__skb)->cb[0])) + #endif /* _NET_BATMAN_ADV_MAIN_H_ */ diff --git a/network-coding.c b/network-coding.c index 0843cb7..3c5249d 100644 --- a/network-coding.c +++ b/network-coding.c @@ -804,6 +804,405 @@ static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv, }

/** + * batadv_nc_random_weight_tq - scale the receivers TQ-value to avoid unfair + * selection of a receiver with slightly lower TQ than the other + * @tq: to be weighted tq value + */ +static uint8_t batadv_nc_random_weight_tq(uint8_t tq) +{ + uint8_t rand_val, rand_tq; + + get_random_bytes(&rand_val, sizeof(rand_val)); + + /* randomize the estimated packet loss (max TQ - estimated TQ) */ + rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq); + + /* normalize the randomized packet loss */ + rand_tq /= BATADV_TQ_MAX_VALUE; + + /* convert to (randomized) estimated tq again */ + return BATADV_TQ_MAX_VALUE - rand_tq; +} + +/** + * batadv_nc_memxor - XOR destination with source + * @dst: byte array to XOR into + * @src: byte array to XOR from + * @len: length of destination array + */ +static void batadv_nc_memxor(char *dst, const char *src, unsigned int len) +{ + unsigned int i; + + for (i = 0; i < len; ++i) + dst[i] ^= src[i]; +} + +/** + * batadv_nc_code_packets - code a received unicast_packet with an nc packet + * into a coded_packet and send it + * @bat_priv: the bat priv with all the soft interface information + * @skb: data skb to forward + * @ethhdr: pointer to the ethernet header inside the skb + * @nc_packet: structure containing the packet to the skb can be coded with + * @neigh_node: next hop to forward packet to + * + * Returns true if both packets are consumed, false otherwise. + */ +static bool batadv_nc_code_packets(struct batadv_priv *bat_priv, + struct sk_buff *skb, + struct ethhdr *ethhdr, + struct batadv_nc_packet *nc_packet, + struct batadv_neigh_node *neigh_node) +{ + uint8_t tq_weighted_neigh, tq_weighted_coding; + struct sk_buff *skb_dest, *skb_src; + struct batadv_unicast_packet *packet1; + struct batadv_unicast_packet *packet2; + struct batadv_coded_packet *coded_packet; + struct batadv_neigh_node *neigh_tmp, *router_neigh; + struct batadv_neigh_node *router_coding = NULL; + uint8_t *first_source, *first_dest, *second_source, *second_dest; + __be32 packet_id1, packet_id2; + size_t count; + bool res = false; + int coding_len; + int unicast_size = sizeof(*packet1); + int coded_size = sizeof(*coded_packet); + int header_add = coded_size - unicast_size; + + router_neigh = batadv_orig_node_get_router(neigh_node->orig_node); + if (!router_neigh) + goto out; + + neigh_tmp = nc_packet->neigh_node; + router_coding = batadv_orig_node_get_router(neigh_tmp->orig_node); + if (!router_coding) + goto out; + + tq_weighted_neigh = batadv_nc_random_weight_tq(router_neigh->tq_avg); + tq_weighted_coding = batadv_nc_random_weight_tq(router_coding->tq_avg); + + /* Select one destination for the MAC-header dst-field based on + * weighted TQ-values. + */ + if (tq_weighted_neigh >= tq_weighted_coding) { + /* Destination from nc_packet is selected for MAC-header */ + first_dest = nc_packet->nc_path->next_hop; + first_source = nc_packet->nc_path->prev_hop; + second_dest = neigh_node->addr; + second_source = ethhdr->h_source; + packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data; + packet2 = (struct batadv_unicast_packet *)skb->data; + packet_id1 = nc_packet->packet_id; + packet_id2 = batadv_skb_crc32(skb, + skb->data + sizeof(*packet2)); + } else { + /* Destination for skb is selected for MAC-header */ + first_dest = neigh_node->addr; + first_source = ethhdr->h_source; + second_dest = nc_packet->nc_path->next_hop; + second_source = nc_packet->nc_path->prev_hop; + packet1 = (struct batadv_unicast_packet *)skb->data; + packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data; + packet_id1 = batadv_skb_crc32(skb, + skb->data + sizeof(*packet1)); + packet_id2 = nc_packet->packet_id; + } + + /* Instead of zero padding the smallest data buffer, we + * code into the largest. + */ + if (skb->len <= nc_packet->skb->len) { + skb_dest = nc_packet->skb; + skb_src = skb; + } else { + skb_dest = skb; + skb_src = nc_packet->skb; + } + + /* coding_len is used when decoding the packet shorter packet */ + coding_len = skb_src->len - unicast_size; + + if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0) + goto out; + + skb_push(skb_dest, header_add); + + coded_packet = (struct batadv_coded_packet *)skb_dest->data; + skb_reset_mac_header(skb_dest); + + coded_packet->header.packet_type = BATADV_CODED; + coded_packet->header.version = BATADV_COMPAT_VERSION; + coded_packet->header.ttl = packet1->header.ttl; + + /* Info about first unicast packet */ + memcpy(coded_packet->first_source, first_source, ETH_ALEN); + memcpy(coded_packet->first_orig_dest, packet1->dest, ETH_ALEN); + coded_packet->first_crc = packet_id1; + coded_packet->first_ttvn = packet1->ttvn; + + /* Info about second unicast packet */ + memcpy(coded_packet->second_dest, second_dest, ETH_ALEN); + memcpy(coded_packet->second_source, second_source, ETH_ALEN); + memcpy(coded_packet->second_orig_dest, packet2->dest, ETH_ALEN); + coded_packet->second_crc = packet_id2; + coded_packet->second_ttl = packet2->header.ttl; + coded_packet->second_ttvn = packet2->ttvn; + coded_packet->coded_len = htons(coding_len); + + /* This is where the magic happens: Code skb_src into skb_dest */ + batadv_nc_memxor(skb_dest->data + coded_size, + skb_src->data + unicast_size, coding_len); + + /* Update counters accordingly */ + if (BATADV_SKB_CB(skb_src)->decoded && + BATADV_SKB_CB(skb_dest)->decoded) { + /* Both packets are recoded */ + count = skb_src->len + ETH_HLEN; + count += skb_dest->len + ETH_HLEN; + batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2); + batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count); + } else if (!BATADV_SKB_CB(skb_src)->decoded && + !BATADV_SKB_CB(skb_dest)->decoded) { + /* Both packets are newly coded */ + count = skb_src->len + ETH_HLEN; + count += skb_dest->len + ETH_HLEN; + batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2); + batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count); + } else if (BATADV_SKB_CB(skb_src)->decoded && + !BATADV_SKB_CB(skb_dest)->decoded) { + /* skb_src recoded and skb_dest is newly coded */ + batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE); + batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, + skb_src->len + ETH_HLEN); + batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE); + batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, + skb_dest->len + ETH_HLEN); + } else if (!BATADV_SKB_CB(skb_src)->decoded && + BATADV_SKB_CB(skb_dest)->decoded) { + /* skb_src is newly coded and skb_dest is recoded */ + batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE); + batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, + skb_src->len + ETH_HLEN); + batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE); + batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, + skb_dest->len + ETH_HLEN); + } + + /* skb_src is now coded into skb_dest, so free it */ + kfree_skb(skb_src); + + /* avoid duplicate free of skb from nc_packet */ + nc_packet->skb = NULL; + batadv_nc_packet_free(nc_packet); + + /* Send the coded packet and return true */ + batadv_send_skb_packet(skb_dest, neigh_node->if_incoming, first_dest); + res = true; +out: + if (router_neigh) + batadv_neigh_node_free_ref(router_neigh); + if (router_coding) + batadv_neigh_node_free_ref(router_coding); + return res; +} + +/** + * batadv_nc_skb_coding_possible - true if a decoded skb is available at dst. + * @skb: data skb to forward + * @dst: destination mac address of the other skb to code with + * @src: source mac address of skb + * + * Whenever we network code a packet we have to check whether we received it in + * a network coded form. If so, we may not be able to use it for coding because + * some neighbors may also have received (overheard) the packet in the network + * coded form without being able to decode it. It is hard to know which of the + * neighboring nodes was able to decode the packet, therefore we can only + * re-code the packet if the source of the previous encoded packet is involved. + * Since the source encoded the packet we can be certain it has all necessary + * decode information. + * + * Returns true if coding of a decoded packet is allowed. + */ +static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, + uint8_t *dst, + uint8_t *src) +{ + if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src)) + return false; + else + return true; +} + +/** + * batadv_nc_path_search - Find the coding path matching in_nc_node and + * out_nc_node to retrieve a buffered packet that can be used for coding. + * @bat_priv: the bat priv with all the soft interface information + * @in_nc_node: pointer to skb next hop's neighbor nc node + * @out_nc_node: pointer to skb source's neighbor nc node + * @skb: data skb to forward + * @eth_dst: next hop mac address of skb + * + * Returns true if coding of a decoded skb is allowed. + */ +static struct batadv_nc_packet * +batadv_nc_path_search(struct batadv_priv *bat_priv, + struct batadv_nc_node *in_nc_node, + struct batadv_nc_node *out_nc_node, + struct sk_buff *skb, + uint8_t *eth_dst) +{ + struct batadv_nc_path *nc_path, nc_path_key; + struct batadv_nc_packet *nc_packet_out = NULL; + struct batadv_nc_packet *nc_packet, *nc_packet_tmp; + struct hlist_node *node; + 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, node, &hash->table[idx], hash_entry) { + if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr)) + continue; + + if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr)) + continue; + + spin_lock_bh(&nc_path->packet_list_lock); + if (list_empty(&nc_path->packet_list)) { + spin_unlock_bh(&nc_path->packet_list_lock); + continue; + } + + list_for_each_entry_safe(nc_packet, nc_packet_tmp, + &nc_path->packet_list, list) { + if (!batadv_nc_skb_coding_possible(nc_packet->skb, + eth_dst, + in_nc_node->addr)) + continue; + + /* Coding opportunity is found! */ + list_del(&nc_packet->list); + nc_packet_out = nc_packet; + break; + } + + spin_unlock_bh(&nc_path->packet_list_lock); + break; + } + rcu_read_unlock(); + + return nc_packet_out; +} + +/** + * batadv_nc_skb_src_search - Loops through the list of neighoring nodes of the + * skb's sender (may be equal to the originator). + * @bat_priv: the bat priv with all the soft interface information + * @skb: data skb to forward + * @eth_dst: next hop mac address of skb + * @eth_src: source mac address of skb + * @in_nc_node: pointer to skb next hop's neighbor nc node + * + * Returns an nc packet if a suitable coding packet was found, NULL otherwise. + */ +static struct batadv_nc_packet * +batadv_nc_skb_src_search(struct batadv_priv *bat_priv, + struct sk_buff *skb, + uint8_t *eth_dst, + uint8_t *eth_src, + struct batadv_nc_node *in_nc_node) +{ + struct batadv_orig_node *orig_node; + struct batadv_nc_node *out_nc_node; + struct batadv_nc_packet *nc_packet = NULL; + + orig_node = batadv_orig_hash_find(bat_priv, eth_src); + if (!orig_node) + return NULL; + + rcu_read_lock(); + list_for_each_entry_rcu(out_nc_node, + &orig_node->out_coding_list, list) { + /* Check if the skb is decoded and if recoding is possible */ + if (!batadv_nc_skb_coding_possible(skb, + out_nc_node->addr, eth_src)) + continue; + + /* Search for an opportunity in this nc_path */ + nc_packet = batadv_nc_path_search(bat_priv, in_nc_node, + out_nc_node, skb, eth_dst); + if (nc_packet) + break; + } + rcu_read_unlock(); + + batadv_orig_node_free_ref(orig_node); + return nc_packet; +} + +/** + * batadv_nc_skb_dst_search - Loops through list of neighboring nodes to dst. + * @skb: data skb to forward + * @neigh_node: next hop to forward packet to + * @ethhdr: pointer to the ethernet header inside the skb + * + * Loops through list of neighboring nodes the next hop has a good connection to + * (receives OGMs with a sufficient quality). We need to find a neighbor of our + * next hop that potentially sent a packet which our next hop also received + * (overheard) and has stored for later decoding. + * + * Returns true if the skb was consumed (encoded packet sent) or false otherwise + */ +static bool batadv_nc_skb_dst_search(struct sk_buff *skb, + struct batadv_neigh_node *neigh_node, + struct ethhdr *ethhdr) +{ + struct net_device *netdev = neigh_node->if_incoming->soft_iface; + struct batadv_priv *bat_priv = netdev_priv(netdev); + struct batadv_orig_node *orig_node = neigh_node->orig_node; + struct batadv_nc_node *nc_node; + struct batadv_nc_packet *nc_packet = NULL; + + rcu_read_lock(); + list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) { + /* Search for coding opportunity with this in_nc_node */ + nc_packet = batadv_nc_skb_src_search(bat_priv, skb, + neigh_node->addr, + ethhdr->h_source, nc_node); + + /* Opportunity was found, so stop searching */ + if (nc_packet) + break; + } + rcu_read_unlock(); + + if (!nc_packet) + return false; + + /* 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 @@ -868,6 +1267,10 @@ bool batadv_nc_skb_forward(struct sk_buff *skb, if (packet->header.packet_type != BATADV_UNICAST) goto out;

+ /* Try to find a coding opportunity and send the skb if one is found */ + if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr)) + return true; + /* Find or create a nc_path for this src-dst pair */ nc_path = batadv_nc_get_path(bat_priv, bat_priv->nc.coding_hash, diff --git a/packet.h b/packet.h index ed0aa89..a079958 100644 --- a/packet.h +++ b/packet.h @@ -30,6 +30,7 @@ enum batadv_packettype { BATADV_TT_QUERY = 0x07, BATADV_ROAM_ADV = 0x08, BATADV_UNICAST_4ADDR = 0x09, + BATADV_CODED = 0x0a, };

/** @@ -278,4 +279,36 @@ struct batadv_tt_change { uint8_t addr[ETH_ALEN]; } __packed;

+/** + * struct batadv_coded_packet - network coded packet + * @header: common batman packet header and ttl of first included packet + * @reserved: Align following fields to 2-byte boundaries + * @first_source: original source of first included packet + * @first_orig_dest: original destinal of first included packet + * @first_crc: checksum of first included packet + * @first_ttvn: tt-version number of first included packet + * @second_ttl: ttl of second packet + * @second_dest: second receiver of this coded packet + * @second_source: original source of second included packet + * @second_orig_dest: original destination of second included packet + * @second_crc: checksum of second included packet + * @second_ttvn: tt version number of second included packet + * @coded_len: length of network coded part of the payload + */ +struct batadv_coded_packet { + struct batadv_header header; + uint8_t first_ttvn; + /* uint8_t first_dest[ETH_ALEN]; - saved in mac header destination */ + uint8_t first_source[ETH_ALEN]; + uint8_t first_orig_dest[ETH_ALEN]; + __be32 first_crc; + uint8_t second_ttl; + uint8_t second_ttvn; + uint8_t second_dest[ETH_ALEN]; + uint8_t second_source[ETH_ALEN]; + uint8_t second_orig_dest[ETH_ALEN]; + __be32 second_crc; + uint16_t coded_len; +}; + #endif /* _NET_BATMAN_ADV_PACKET_H_ */ diff --git a/soft-interface.c b/soft-interface.c index 7188e07..7e463c3 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -665,6 +665,12 @@ static const struct { { "dat_put_rx" }, { "dat_cached_reply_tx" }, #endif +#ifdef CONFIG_BATMAN_ADV_NC + { "nc_code" }, + { "nc_code_bytes" }, + { "nc_recode" }, + { "nc_recode_bytes" }, +#endif };

static void batadv_get_strings(struct net_device *dev, uint32_t stringset, diff --git a/types.h b/types.h index 6f19d08..8d72160 100644 --- a/types.h +++ b/types.h @@ -275,6 +275,10 @@ struct batadv_bcast_duplist_entry { * @BATADV_CNT_DAT_PUT_RX: received dht PUT traffic packet counter * @BATADV_CNT_DAT_CACHED_REPLY_TX: transmitted dat cache reply traffic packet * counter + * @BATADV_CNT_NC_CODE: transmitted nc-combined traffic packet counter + * @BATADV_CNT_NC_CODE_BYTES: transmitted nc-combined traffic bytes counter + * @BATADV_CNT_NC_RECODE: transmitted nc-recombined traffic packet counter + * @BATADV_CNT_NC_RECODE_BYTES: transmitted nc-recombined traffic bytes counter * @BATADV_CNT_NUM: number of traffic counters */ enum batadv_counters { @@ -302,6 +306,12 @@ enum batadv_counters { BATADV_CNT_DAT_PUT_RX, BATADV_CNT_DAT_CACHED_REPLY_TX, #endif +#ifdef CONFIG_BATMAN_ADV_NC + BATADV_CNT_NC_CODE, + BATADV_CNT_NC_CODE_BYTES, + BATADV_CNT_NC_RECODE, + BATADV_CNT_NC_RECODE_BYTES, +#endif BATADV_CNT_NUM, };

@@ -797,6 +807,16 @@ struct batadv_nc_packet { };

/** + * batadv_skb_cb - control buffer structure used to store private data relevant + * to batman-adv in the skb->cb buffer in skbs. + * @decoded: Marks a skb as decoded, which is checked when searching for coding + * opportunities in network-coding.c + */ +struct batadv_skb_cb { + bool decoded; +}; + +/** * struct batadv_forw_packet - structure for bcast packets to be sent/forwarded * @list: list node for batadv_socket_client::queue_list * @send_time: execution time for delayed_work (packet sending)

When receiving a network coded packet, the decoding buffer is searched for a packet to use for decoding. The source, destination, and crc32 from the coded packet is used to identify the wanted packet. The decoded packet is passed to the usual unicast receiver function, as had it never been network coded.

Signed-off-by: Martin Hundebøll martin@hundeboll.net --- v3: * Free nc_packet in batadv_nc_recv_coded_packet() to avoid mem-leaks v4: * Add missing kernel doc entry for enum batadv_counters

network-coding.c | 234 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ soft-interface.c | 4 + types.h | 10 +++ 3 files changed, 248 insertions(+)

diff --git a/network-coding.c b/network-coding.c index af96211..57069ae 100644 --- a/network-coding.c +++ b/network-coding.c @@ -25,11 +25,14 @@ #include "send.h" #include "originator.h" #include "hard-interface.h" +#include "routing.h"

static struct lock_class_key batadv_nc_coding_hash_lock_class_key; static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;

static void batadv_nc_worker(struct work_struct *work); +static int batadv_nc_recv_coded_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if);

/** * batadv_nc_start_timer - initialise the nc periodic worker @@ -67,6 +70,11 @@ int batadv_nc_init(struct batadv_priv *bat_priv) batadv_hash_set_lock_class(bat_priv->nc.coding_hash, &batadv_nc_decoding_hash_lock_class_key);

+ /* Register our packet type */ + if (batadv_recv_handler_register(BATADV_CODED, + batadv_nc_recv_coded_packet) < 0) + goto err; + INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker); batadv_nc_start_timer(bat_priv);

@@ -1494,11 +1502,237 @@ void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv, }

/** + * batadv_nc_skb_decode_packet - decode given skb using the decode data stored + * in nc_packet + * @skb: unicast skb to decode + * @nc_packet: decode data needed to decode the skb + * + * Returns pointer to decoded unicast packet if the packet was decoded or NULL + * in case of an error. + */ +static struct batadv_unicast_packet * +batadv_nc_skb_decode_packet(struct sk_buff *skb, + struct batadv_nc_packet *nc_packet) +{ + const int h_size = sizeof(struct batadv_unicast_packet); + const int h_diff = sizeof(struct batadv_coded_packet) - h_size; + struct batadv_unicast_packet *unicast_packet; + struct batadv_coded_packet coded_packet_tmp; + struct ethhdr *ethhdr, ethhdr_tmp; + uint8_t *orig_dest, ttl, ttvn; + unsigned int coding_len; + + /* Save headers temporarily */ + memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp)); + memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp)); + + if (skb_cow(skb, 0) < 0) + return NULL; + + if (unlikely(!skb_pull_rcsum(skb, h_diff))) + return NULL; + + /* Data points to batman header, so set mac header 14 bytes before + * and network to data + */ + skb_set_mac_header(skb, -ETH_HLEN); + skb_reset_network_header(skb); + + /* Reconstruct original mac header */ + ethhdr = (struct ethhdr *)skb_mac_header(skb); + memcpy(ethhdr, &ethhdr_tmp, sizeof(*ethhdr)); + + /* Select the correct unicast header information based on the location + * of our mac address in the coded_packet header + */ + if (batadv_is_my_mac(coded_packet_tmp.second_dest)) { + /* If we are the second destination the packet was overheard, + * so the Ethernet address must be copied to h_dest and + * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST + */ + memcpy(ethhdr->h_dest, coded_packet_tmp.second_dest, ETH_ALEN); + skb->pkt_type = PACKET_HOST; + + orig_dest = coded_packet_tmp.second_orig_dest; + ttl = coded_packet_tmp.second_ttl; + ttvn = coded_packet_tmp.second_ttvn; + } else { + orig_dest = coded_packet_tmp.first_orig_dest; + ttl = coded_packet_tmp.header.ttl; + ttvn = coded_packet_tmp.first_ttvn; + } + + coding_len = ntohs(coded_packet_tmp.coded_len); + + if (coding_len > skb->len) + return NULL; + + /* Here the magic is reversed: + * extract the missing packet from the received coded packet + */ + batadv_nc_memxor(skb->data + h_size, + nc_packet->skb->data + h_size, + coding_len); + + /* Resize decoded skb if decoded with larger packet */ + if (nc_packet->skb->len > coding_len + h_size) + pskb_trim_rcsum(skb, coding_len + h_size); + + /* Create decoded unicast packet */ + unicast_packet = (struct batadv_unicast_packet *)skb->data; + unicast_packet->header.packet_type = BATADV_UNICAST; + unicast_packet->header.version = BATADV_COMPAT_VERSION; + unicast_packet->header.ttl = ttl; + memcpy(unicast_packet->dest, orig_dest, ETH_ALEN); + unicast_packet->ttvn = ttvn; + + batadv_nc_packet_free(nc_packet); + return unicast_packet; +} + +/** + * batadv_nc_find_decoding_packet - search through buffered decoding data to + * find the data needed to decode the coded packet + * @bat_priv: the bat priv with all the soft interface information + * @ethhdr: pointer to the ethernet header inside the coded packet + * @coded: coded packet we try to find decode data for + * + * Returns pointer to nc packet if the needed data was found or NULL otherwise. + */ +static struct batadv_nc_packet * +batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv, + struct ethhdr *ethhdr, + struct batadv_coded_packet *coded) +{ + struct batadv_hashtable *hash = bat_priv->nc.decoding_hash; + struct hlist_node *hnode; + struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL; + struct batadv_nc_path *nc_path, nc_path_key; + uint8_t *dest, *source; + __be32 packet_id; + int index; + + if (!hash) + return NULL; + + /* Select the correct packet id based on the location of our mac-addr */ + dest = ethhdr->h_source; + if (!batadv_is_my_mac(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, hnode, &hash->table[index], + hash_entry) { + /* Find matching nc_packet */ + spin_lock_bh(&nc_path->packet_list_lock); + list_for_each_entry(tmp_nc_packet, + &nc_path->packet_list, list) { + if (packet_id == tmp_nc_packet->packet_id) { + list_del(&tmp_nc_packet->list); + + nc_packet = tmp_nc_packet; + break; + } + } + spin_unlock_bh(&nc_path->packet_list_lock); + + if (nc_packet) + break; + } + rcu_read_unlock(); + + if (!nc_packet) + batadv_dbg(BATADV_DBG_NC, bat_priv, + "No decoding packet found for %u\n", packet_id); + + return nc_packet; +} + +/** + * batadv_nc_recv_coded_packet - try to decode coded packet and enqueue the + * resulting unicast packet + * @skb: incoming coded packet + * @recv_if: pointer to interface this packet was received on + */ +static int batadv_nc_recv_coded_packet(struct sk_buff *skb, + struct batadv_hard_iface *recv_if) +{ + struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface); + struct batadv_unicast_packet *unicast_packet; + struct batadv_coded_packet *coded_packet; + struct batadv_nc_packet *nc_packet; + struct ethhdr *ethhdr; + int hdr_size = sizeof(*coded_packet); + + /* Check if network coding is enabled */ + if (!atomic_read(&bat_priv->network_coding)) + return NET_RX_DROP; + + /* Make sure we can access (and remove) header */ + if (unlikely(!pskb_may_pull(skb, hdr_size))) + return NET_RX_DROP; + + coded_packet = (struct batadv_coded_packet *)skb->data; + ethhdr = (struct ethhdr *)skb_mac_header(skb); + + /* Verify frame is destined for us */ + if (!batadv_is_my_mac(ethhdr->h_dest) && + !batadv_is_my_mac(coded_packet->second_dest)) + return NET_RX_DROP; + + /* Update stat counter */ + if (batadv_is_my_mac(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(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_free - clean up network coding memory * @bat_priv: the bat priv with all the soft interface information */ void batadv_nc_free(struct batadv_priv *bat_priv) { + batadv_recv_handler_unregister(BATADV_CODED); cancel_delayed_work_sync(&bat_priv->nc.work);

batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL); diff --git a/soft-interface.c b/soft-interface.c index 75204ec..f93ae42 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -671,6 +671,10 @@ static const struct { { "nc_recode" }, { "nc_recode_bytes" }, { "nc_buffer" }, + { "nc_decode" }, + { "nc_decode_bytes" }, + { "nc_decode_failed" }, + { "nc_sniffed" }, #endif };

diff --git a/types.h b/types.h index 08a3c30..76dec7c 100644 --- a/types.h +++ b/types.h @@ -280,6 +280,12 @@ struct batadv_bcast_duplist_entry { * @BATADV_CNT_NC_RECODE: transmitted nc-recombined traffic packet counter * @BATADV_CNT_NC_RECODE_BYTES: transmitted nc-recombined traffic bytes counter * @BATADV_CNT_NC_BUFFER: counter for packets buffered for later nc decoding + * @BATADV_CNT_NC_DECODE: received and nc-decoded traffic packet counter + * @BATADV_CNT_NC_DECODE_BYTES: received and nc-decoded traffic bytes counter + * @BATADV_CNT_NC_DECODE_FAILED: received and decode-failed traffic packet + * counter + * @BATADV_CNT_NC_SNIFFED: counter for nc-decoded packets received in promisc + * mode. * @BATADV_CNT_NUM: number of traffic counters */ enum batadv_counters { @@ -313,6 +319,10 @@ enum batadv_counters { BATADV_CNT_NC_RECODE, BATADV_CNT_NC_RECODE_BYTES, BATADV_CNT_NC_BUFFER, + BATADV_CNT_NC_DECODE, + BATADV_CNT_NC_DECODE_BYTES, + BATADV_CNT_NC_DECODE_FAILED, + BATADV_CNT_NC_SNIFFED, #endif BATADV_CNT_NUM, };