Network coding exploits the 802.11 shared medium to allow multiple packets to be sent in a single transmission. In brief, a relay can XOR two packets, and send the coded packet to two destinations. The receivers can decode one of the original packets by XOR'ing the coded packet with the other original packet. This will lead to increased throughput in topologies where two packets cross one relay. In a simple topology with three nodes, it takes four transmissions without network coding to get one packet from Node A to Node B and one from Node B to Node A: 1. Node A ---- p1 ---> Node R Node B 2. Node A Node R <--- p2 ---- Node B 3. Node A <--- p2 ---- Node R Node B 4. Node A Node R ---- p1 ---> Node B With network coding, the relay only needs one transmission, which saves us one slot of valuable airtime: 1. Node A ---- p1 ---> Node R Node B 2. Node A Node R <--- p2 ---- Node B 3. Node A <- p1 x p2 - Node R - p1 x p2 -> Node B The same principle holds for a topology including five nodes. Here the packets from Node A and Node B are overheard by Node C and Node D, respectively. This allows Node R to send a network coded packet to save one transmission: Node A Node B | \ / | | p1 p2 | | \ / | p1 > Node R < p2 | | | / \ | | p1 x p2 p1 x p2 | v / \ v / \ Node C < > Node D More information is available on the open-mesh.org wiki[1]. This patch adds the initial code to support network coding in batman-adv. It sets up a worker thread to do house keeping and adds a sysfs file to enable/disable network coding. The feature is disabled by default, as it requires a wifi-driver with working promiscuous mode, and also because it adds a small delay at each hop. [1] http://www.open-mesh.org/projects/batman-adv/wiki/Catwoman Signed-off-by: Martin Hundebøll &lt;martin(a)hundeboll.net&gt; --- Makefile | 2 ++ Makefile.kbuild | 1 + gen-compat-autoconf.sh | 1 + main.c | 6 ++++ main.h | 4 ++- network-coding.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++ network-coding.h | 48 ++++++++++++++++++++++++++++++ soft-interface.c | 3 ++ sysfs-class-net-mesh | 8 +++++ sysfs.c | 6 ++++ types.h | 17 +++++++++++ 11 files changed, 176 insertions(+), 1 deletion(-) create mode 100644 network-coding.c create mode 100644 network-coding.h diff --git a/Makefile b/Makefile index 4d70e40..d41f947 100644 --- a/Makefile +++ b/Makefile @@ -25,6 +25,8 @@ export CONFIG_BATMAN_ADV_DEBUG=n export CONFIG_BATMAN_ADV_BLA=y # B.A.T.M.A.N. distributed ARP table: export CONFIG_BATMAN_ADV_DAT=y +# B.A.T.M.A.N network coding (catwoman): +export CONFIG_BATMAN_ADV_NC=n PWD:=$(shell pwd) KERNELPATH ?= /lib/modules/$(shell uname -r)/build diff --git a/Makefile.kbuild b/Makefile.kbuild index e45e3b4..4b8f192 100644 --- a/Makefile.kbuild +++ b/Makefile.kbuild @@ -30,6 +30,7 @@ batman-adv-y += hard-interface.o batman-adv-y += hash.o batman-adv-y += icmp_socket.o batman-adv-y += main.o +batman-adv-$(CONFIG_BATMAN_ADV_NC) += network-coding.o batman-adv-y += originator.o batman-adv-y += ring_buffer.o batman-adv-y += routing.o diff --git a/gen-compat-autoconf.sh b/gen-compat-autoconf.sh index 7ea42aa..78573e4 100755 --- a/gen-compat-autoconf.sh +++ b/gen-compat-autoconf.sh @@ -39,6 +39,7 @@ gen_config() { gen_config 'CONFIG_BATMAN_ADV_DEBUG' ${CONFIG_BATMAN_ADV_DEBUG:="n"} >> "${TMP}" gen_config 'CONFIG_BATMAN_ADV_BLA' ${CONFIG_BATMAN_ADV_BLA:="y"} >> "${TMP}" gen_config 'CONFIG_BATMAN_ADV_DAT' ${CONFIG_BATMAN_ADV_DAT:="y"} >> "${TMP}" +gen_config 'CONFIG_BATMAN_ADV_NC' ${CONFIG_BATMAN_ADV_NC:="n"} >> "${TMP}" # only regenerate compat-autoconf.h when config was changed diff "${TMP}" "${TARGET}" > /dev/null 2>&1 || cp "${TMP}" "${TARGET}" diff --git a/main.c b/main.c index f65a222..f08c057 100644 --- a/main.c +++ b/main.c @@ -35,6 +35,7 @@ #include "vis.h" #include "hash.h" #include "bat_algo.h" +#include "network-coding.h" /* List manipulations on hardif_list have to be rtnl_lock()'ed, @@ -135,6 +136,10 @@ int batadv_mesh_init(struct net_device *soft_iface) if (ret < 0) goto err; + ret = batadv_nc_init(bat_priv); + if (ret < 0) + goto err; + atomic_set(&bat_priv->gw.reselect, 0); atomic_set(&bat_priv->mesh_state, BATADV_MESH_ACTIVE); @@ -157,6 +162,7 @@ void batadv_mesh_free(struct net_device *soft_iface) batadv_gw_node_purge(bat_priv); batadv_originator_free(bat_priv); + batadv_nc_free(bat_priv); batadv_tt_free(bat_priv); diff --git a/main.h b/main.h index 2032de2..ee09f0f 100644 --- a/main.h +++ b/main.h @@ -185,6 +185,7 @@ __be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr); * @BATADV_DBG_TT: translation table messages * @BATADV_DBG_BLA: bridge loop avoidance messages * @BATADV_DBG_DAT: ARP snooping and DAT related messages + * @BATADV_DBG_NC: network coding related messages * @BATADV_DBG_ALL: the union of all the above log levels */ enum batadv_dbg_level { @@ -193,7 +194,8 @@ enum batadv_dbg_level { BATADV_DBG_TT = BIT(2), BATADV_DBG_BLA = BIT(3), BATADV_DBG_DAT = BIT(4), - BATADV_DBG_ALL = 31, + BATADV_DBG_NC = BIT(5), + BATADV_DBG_ALL = 63, }; #ifdef CONFIG_BATMAN_ADV_DEBUG diff --git a/network-coding.c b/network-coding.c new file mode 100644 index 0000000..4f0409d --- /dev/null +++ b/network-coding.c @@ -0,0 +1,81 @@ +/* Copyright (C) 2007-2012 B.A.T.M.A.N. contributors: + * + * Martin Hundebøll, Jeppe Ledet-Pedersen + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA + */ + +#include "main.h" +#include "network-coding.h" + +static void batadv_nc_worker(struct work_struct *work); + +/** + * batadv_nc_start_timer - initialise the nc periodic worker + * @bat_priv: the bat priv with all the soft interface information + */ +static void batadv_nc_start_timer(struct batadv_priv *bat_priv) +{ + queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work, + msecs_to_jiffies(10)); +} + +/** + * batadv_nc_init - initialise coding hash table and start house keeping + * @bat_priv: the bat priv with all the soft interface information + */ +int batadv_nc_init(struct batadv_priv *bat_priv) +{ + INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker); + batadv_nc_start_timer(bat_priv); + + return 0; +} + +/** + * batadv_nc_init_bat_priv - initialise the nc specific bat_priv variables + * @bat_priv: the bat priv with all the soft interface information + */ +void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv) +{ + atomic_set(&bat_priv->network_coding, 1); +} + +/** + * batadv_nc_worker - periodic task for house keeping related to network coding + * @work: kernel work struct + */ +static void batadv_nc_worker(struct work_struct *work) +{ + struct delayed_work *delayed_work; + struct batadv_priv_nc *priv_nc; + struct batadv_priv *bat_priv; + + delayed_work = container_of(work, struct delayed_work, work); + priv_nc = container_of(delayed_work, struct batadv_priv_nc, work); + bat_priv = container_of(priv_nc, struct batadv_priv, nc); + + /* Schedule a new check */ + batadv_nc_start_timer(bat_priv); +} + +/** + * 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) +{ + cancel_delayed_work_sync(&bat_priv->nc.work); +} diff --git a/network-coding.h b/network-coding.h new file mode 100644 index 0000000..b805899 --- /dev/null +++ b/network-coding.h @@ -0,0 +1,48 @@ +/* Copyright (C) 2007-2012 B.A.T.M.A.N. contributors: + * + * Martin Hundebøll, Jeppe Ledet-Pedersen + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA + */ + +#ifndef _NET_BATMAN_ADV_NETWORK_CODING_H +#define _NET_BATMAN_ADV_NETWORK_CODING_H + +#ifdef CONFIG_BATMAN_ADV_NC + +int batadv_nc_init(struct batadv_priv *bat_priv); +void batadv_nc_free(struct batadv_priv *bat_priv); +void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv); + +#else /* ifdef CONFIG_BATMAN_ADV_NC */ + +static inline int batadv_nc_init(struct batadv_priv *bat_priv) +{ + return 0; +} + +static inline void batadv_nc_free(struct batadv_priv *bat_priv) +{ + return; +} + +static inline void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv) +{ + return; +} + +#endif /* ifdef CONFIG_BATMAN_ADV_NC */ + +#endif /* _NET_BATMAN_ADV_NETWORK_CODING_H */ diff --git a/soft-interface.c b/soft-interface.c index fcf8acc..69ad5e2 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -37,6 +37,7 @@ #include <linux/if_ether.h> #include "unicast.h" #include "bridge_loop_avoidance.h" +#include "network-coding.h" static int batadv_get_settings(struct net_device *dev, struct ethtool_cmd *cmd); @@ -515,6 +516,8 @@ struct net_device *batadv_softif_create(const char *name) if (ret < 0) goto unreg_soft_iface; + batadv_nc_init_bat_priv(bat_priv); + ret = batadv_sysfs_add_meshif(soft_iface); if (ret < 0) goto unreg_soft_iface; diff --git a/sysfs-class-net-mesh b/sysfs-class-net-mesh index bc41da6..bdcd8b4 100644 --- a/sysfs-class-net-mesh +++ b/sysfs-class-net-mesh @@ -67,6 +67,14 @@ Description: Defines the penalty which will be applied to an originator message's tq-field on every hop. +What: /sys/class/net/<mesh_iface>/mesh/network_coding +Date: Nov 2012 +Contact: Martin Hundeboll &lt;martin(a)hundeboll.net&gt; +Description: + Controls whether Network Coding (using some magic + to send fewer wifi packets but still the same + content) is enabled or not. + What: /sys/class/net/<mesh_iface>/mesh/orig_interval Date: May 2010 Contact: Marek Lindner &lt;lindner_marek(a)yahoo.de&gt; diff --git a/sysfs.c b/sysfs.c index 84a55cb..e48a62b 100644 --- a/sysfs.c +++ b/sysfs.c @@ -442,6 +442,9 @@ static BATADV_ATTR(gw_bandwidth, S_IRUGO | S_IWUSR, batadv_show_gw_bwidth, #ifdef CONFIG_BATMAN_ADV_DEBUG BATADV_ATTR_SIF_UINT(log_level, S_IRUGO | S_IWUSR, 0, BATADV_DBG_ALL, NULL); #endif +#ifdef CONFIG_BATMAN_ADV_NC +BATADV_ATTR_SIF_BOOL(network_coding, S_IRUGO | S_IWUSR, NULL); +#endif static struct batadv_attribute *batadv_mesh_attrs[] = { &batadv_attr_aggregated_ogms, @@ -464,6 +467,9 @@ static struct batadv_attribute *batadv_mesh_attrs[] = { #ifdef CONFIG_BATMAN_ADV_DEBUG &batadv_attr_log_level, #endif +#ifdef CONFIG_BATMAN_ADV_NC + &batadv_attr_network_coding, +#endif NULL, }; diff --git a/types.h b/types.h index ae9ac9a..5451fc8 100644 --- a/types.h +++ b/types.h @@ -265,6 +265,19 @@ struct batadv_priv_dat { }; #endif +/** + * struct batadv_priv_nc - per mesh interface network coding private data + * @work: work queue callback item for cleanup + */ +struct batadv_priv_nc { + struct delayed_work work; +}; + +/** + * struct batadv_priv - per mesh interface private data + * @network_coding: enable/disable network coding + * @batadv_priv_nc: network coding private data + */ struct batadv_priv { atomic_t mesh_state; struct net_device_stats stats; @@ -308,6 +321,10 @@ struct batadv_priv { #ifdef CONFIG_BATMAN_ADV_DAT struct batadv_priv_dat dat; #endif +#ifdef CONFIG_BATMAN_ADV_NC + atomic_t network_coding; /* boolean */ + struct batadv_priv_nc nc; +#endif /* CONFIG_BATMAN_ADV_NC */ }; struct batadv_socket_client { -- 1.8.0.1

Two be able to network code two packets, one packet must be buffered until the next is available. This is done in a "coding buffer", which is essentially a hash table with lists of packets. Each entry in the hash table corresponds to a specific src-dst pair, which has a linked list of packets that are buffered. This patch adds skbs to the buffer just before forwarding them. The buffer is traversed every 10 ms, where timed skbs are removed from the buffer and transmitted. To allow experiments with the network coding scheme, the timeout is tunable through a file in debugfs. Signed-off-by: Martin Hundebøll &lt;martin(a)hundeboll.net&gt; --- compat.c | 10 ++ compat.h | 1 + main.h | 1 + network-coding.c | 495 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- network-coding.h | 10 ++ routing.c | 18 +- types.h | 49 ++++++ 7 files changed, 574 insertions(+), 10 deletions(-) diff --git a/compat.c b/compat.c index c8006c6..5664d90 100644 --- a/compat.c +++ b/compat.c @@ -74,4 +74,14 @@ void batadv_free_rcu_dat_entry(struct rcu_head *rcu) } #endif +#ifdef CONFIG_BATMAN_ADV_NC +void batadv_free_rcu_nc_path(struct rcu_head *rcu) +{ + struct batadv_nc_path *nc_path; + + nc_path = container_of(rcu, struct batadv_nc_path, rcu); + kfree(nc_path); +} +#endif + #endif /* < KERNEL_VERSION(3, 0, 0) */ diff --git a/compat.h b/compat.h index 07ac401..3c7ad44 100644 --- a/compat.h +++ b/compat.h @@ -145,6 +145,7 @@ void batadv_free_rcu_neigh_node(struct rcu_head *rcu); void batadv_free_rcu_tt_local_entry(struct rcu_head *rcu); void batadv_free_rcu_backbone_gw(struct rcu_head *rcu); void batadv_free_rcu_dat_entry(struct rcu_head *rcu); +void batadv_free_rcu_nc_path(struct rcu_head *rcu); static inline void skb_reset_mac_len(struct sk_buff *skb) { diff --git a/main.h b/main.h index 44945dc..9fd81b8 100644 --- a/main.h +++ b/main.h @@ -104,6 +104,7 @@ #define BATADV_EXPECTED_SEQNO_RANGE 65536 #define BATADV_NC_NODE_TIMEOUT 10000 /* Milliseconds */ +#define BATADV_NC_PATH_TIMEOUT 10000 /* Milliseconds */ enum batadv_mesh_state { BATADV_MESH_INACTIVE, diff --git a/network-coding.c b/network-coding.c index d9a601d..85288f2 100644 --- a/network-coding.c +++ b/network-coding.c @@ -20,10 +20,14 @@ #include <linux/debugfs.h> #include "main.h" +#include "hash.h" #include "network-coding.h" +#include "send.h" #include "originator.h" #include "hard-interface.h" +static struct lock_class_key batadv_nc_coding_hash_lock_class_key; + static void batadv_nc_worker(struct work_struct *work); /** @@ -42,10 +46,24 @@ static void batadv_nc_start_timer(struct batadv_priv *bat_priv) */ int batadv_nc_init(struct batadv_priv *bat_priv) { + bat_priv->nc.timestamp_fwd_flush = jiffies; + + if (bat_priv->nc.coding_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); + INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker); batadv_nc_start_timer(bat_priv); - return 0; + +err: + return -ENOMEM; } /** @@ -56,6 +74,7 @@ void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv) { atomic_set(&bat_priv->network_coding, 1); bat_priv->nc.min_tq = 200; + bat_priv->nc.max_fwd_delay = 10; } /** @@ -96,6 +115,30 @@ static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node) } /** + * batadv_nc_path_free_ref - decrements the nc path refcounter and possibly + * frees it + * @nc_path: the nc node to free + */ +static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path) +{ + if (atomic_dec_and_test(&nc_path->refcount)) + kfree_rcu(nc_path, rcu); +} + +/** + * batadv_nc_packet_free - frees nc packet + * @nc_packet: the nc packet to free + */ +static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet) +{ + if (nc_packet->skb) + kfree_skb(nc_packet->skb); + + batadv_nc_path_free_ref(nc_packet->nc_path); + kfree(nc_packet); +} + +/** * batadv_nc_to_purge_nc_node - checks whether an nc node has to be purged * @bat_priv: the bat priv with all the soft interface information * @nc_node: the nc node to check @@ -112,6 +155,26 @@ static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv, } /** + * batadv_nc_to_purge_nc_path_coding - checks whether an nc path has timed out + * @bat_priv: the bat priv with all the soft interface information + * @nc_path: the nc path to check + * + * Returns true if the entry has to be purged now, false otherwise + */ +static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv, + struct batadv_nc_path *nc_path) +{ + if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE) + return true; + + /* purge the path when no packets has been added for 10 times the + * max_fwd_delay time + */ + return batadv_has_timed_out(nc_path->last_valid, + bat_priv->nc.max_fwd_delay*10); +} + +/** * batadv_nc_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 @@ -204,6 +267,266 @@ 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 *)) +{ + struct hlist_head *head; + struct hlist_node *node, *node_tmp; + struct batadv_nc_path *nc_path; + spinlock_t *lock; /* Protects lists in hash */ + uint32_t i; + + for (i = 0; i < hash->size; i++) { + head = &hash->table[i]; + lock = &hash->list_locks[i]; + + /* For each nc_path in this bin */ + spin_lock_bh(lock); + hlist_for_each_entry_safe(nc_path, node, 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 and + * leaks memory, so warn about it + */ + 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(node); + batadv_nc_path_free_ref(nc_path); + } + spin_unlock_bh(lock); + } +} + +/** + * batadv_nc_hash_key_gen - computes the nc_path hash key + * @key: buffer to hold the final hash key + * @src: source ethernet mac address going into the hash key + * @dst: destination ethernet mac address going into the hash key + */ +static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, + const char *src, + const char *dst) +{ + memcpy(key->prev_hop, src, sizeof(key->prev_hop)); + memcpy(key->next_hop, dst, sizeof(key->next_hop)); +} + +/** + * batadv_nc_hash_choose - compute the hash value for an nc path + * @data: data to hash + * @size: size of the hash table + * + * Returns the selected index in the hash table for the given data. + */ +static uint32_t batadv_nc_hash_choose(const void *data, uint32_t size) +{ + const struct batadv_nc_path *nc_path = data; + uint32_t hash = 0; + + hash = batadv_hash_bytes(hash, &nc_path->prev_hop, + sizeof(nc_path->prev_hop)); + hash = batadv_hash_bytes(hash, &nc_path->next_hop, + sizeof(nc_path->next_hop)); + + hash += (hash << 3); + hash ^= (hash >> 11); + hash += (hash << 15); + + return hash % size; +} + +/** + * batadv_nc_hash_compare - comparing function used in the network coding hash + * tables + * @node: node in the local table + * @data2: second object to compare the node to + * + * Returns 1 if the two entry are the same, 0 otherwise + */ +static int batadv_nc_hash_compare(const struct hlist_node *node, + const void *data2) +{ + const struct batadv_nc_path *nc_path1, *nc_path2; + + nc_path1 = container_of(node, struct batadv_nc_path, hash_entry); + nc_path2 = data2; + + /* Return true if the two keys are identical */ + if (memcmp(nc_path1->prev_hop, nc_path2->prev_hop, + sizeof(nc_path1->prev_hop)) != 0) + return 0; + + if (memcmp(nc_path1->next_hop, nc_path2->next_hop, + sizeof(nc_path1->next_hop)) != 0) + return 0; + + return 1; +} + +/** + * batadv_nc_hash_find - search for an existing nc path and return it + * @hash: hash table containing the nc path + * @data: search key + * + * Returns the nc_path if found, NULL otherwise. + */ +static struct batadv_nc_path * +batadv_nc_hash_find(struct batadv_hashtable *hash, + void *data) +{ + struct hlist_head *head; + struct hlist_node *node; + 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, node, head, hash_entry) { + if (!batadv_nc_hash_compare(node, data)) + continue; + + if (!atomic_inc_not_zero(&nc_path->refcount)) + continue; + + nc_path_tmp = nc_path; + break; + } + rcu_read_unlock(); + + return nc_path_tmp; +} + +/** + * batadv_nc_send_packet - send non-coded packet and free nc_packet struct + * @nc_packet: the nc packet to send + */ +static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet) +{ + batadv_send_skb_packet(nc_packet->skb, + nc_packet->neigh_node->if_incoming, + nc_packet->nc_path->next_hop); + nc_packet->skb = NULL; + batadv_nc_packet_free(nc_packet); +} + +/** + * batadv_nc_fwd_flush - 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. + * @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 + * + * Returns false as soon as the entry in the fifo queue has not been timed out + * yet and true otherwise. + */ +static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv, + struct batadv_nc_path *nc_path, + struct batadv_nc_packet *nc_packet) +{ + unsigned long timeout = bat_priv->nc.max_fwd_delay; + + /* Packets are added to tail, so the remaining packets did not time + * out and we can stop processing the current queue + */ + if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE && + !batadv_has_timed_out(nc_packet->timestamp, timeout)) + return false; + + /* Send packet */ + batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD); + batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES, + nc_packet->skb->len + ETH_HLEN); + list_del(&nc_packet->list); + batadv_nc_send_packet(nc_packet); + + return true; +} + +/** + * batadv_nc_process_nc_paths - traverse given nc packet pool and + * @bat_priv: the bat priv with all the soft interface information + * @hash: to be processed hash table + * process_fn: Function called to process given nc packet. Should return true + * to encourage this function to proceed with the next packet. + * Otherwise the rest of the current queue is skipped. + */ +static void +batadv_nc_process_nc_paths(struct batadv_priv *bat_priv, + struct batadv_hashtable *hash, + bool (*process_fn)(struct batadv_priv *, + struct batadv_nc_path *, + struct batadv_nc_packet *)) +{ + struct hlist_node *node; + struct hlist_head *head; + spinlock_t *packet_list_lock; /* Protects lists in hash table */ + 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, node, head, hash_entry) { + packet_list_lock = &nc_path->packet_list_lock; + + /* Loop packets */ + spin_lock_bh(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(packet_list_lock); + } + rcu_read_unlock(); + } +} + +/** * batadv_nc_worker - periodic task for house keeping related to network coding * @work: kernel work struct */ @@ -212,20 +535,29 @@ static void batadv_nc_worker(struct work_struct *work) struct delayed_work *delayed_work; struct batadv_priv_nc *priv_nc; struct batadv_priv *bat_priv; + unsigned long timeout; delayed_work = container_of(work, struct delayed_work, work); priv_nc = container_of(delayed_work, struct batadv_priv_nc, work); bat_priv = container_of(priv_nc, struct batadv_priv, nc); batadv_nc_purge_orig_hash(bat_priv); + batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, + batadv_nc_to_purge_nc_path_coding); + + 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; + } /* Schedule a new check */ batadv_nc_start_timer(bat_priv); } /** -<<<<<<< HEAD -======= * 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 @@ -410,12 +742,164 @@ out: } /** + * batadv_nc_get_path - get existing nc_path or allocate a new one + * @bat_priv: the bat priv with all the soft interface information + * @hash: hash table containing the nc path + * @src: ethernet source address - first half of the nc path search key + * @dst: ethernet destination address - second half of the nc path search key + * + * Returns pointer to nc_path if the path was found or created, returns NULL + * on error. + */ +static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv, + struct batadv_hashtable *hash, + uint8_t *src, + uint8_t *dst) +{ + int hash_added; + struct batadv_nc_path *nc_path, nc_path_key; + + batadv_nc_hash_key_gen(&nc_path_key, src, dst); + + /* Search for existing nc_path */ + nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key); + + if (nc_path) { + /* Set timestamp to delay removal of nc_path */ + nc_path->last_valid = jiffies; + return nc_path; + } + + /* No existing nc_path was found; create a new */ + nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC); + + if (!nc_path) + return NULL; + + /* Initialize nc_path */ + INIT_LIST_HEAD(&nc_path->packet_list); + spin_lock_init(&nc_path->packet_list_lock); + atomic_set(&nc_path->refcount, 2); + nc_path->last_valid = jiffies; + memcpy(nc_path->next_hop, dst, ETH_ALEN); + memcpy(nc_path->prev_hop, src, ETH_ALEN); + + batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n", + nc_path->prev_hop, + nc_path->next_hop); + + /* Add nc_path to hash table */ + hash_added = batadv_hash_add(hash, batadv_nc_hash_compare, + batadv_nc_hash_choose, + (void *)&nc_path_key, + &nc_path->hash_entry); + + if (hash_added < 0) { + kfree(nc_path); + return NULL; + } + + return nc_path; +} + +/** + * batadv_nc_skb_add_to_path - buffer skb for later encoding / decoding + * @skb: skb to add to path + * @nc_path: path to add skb to + * @neigh_node: next hop to forward packet to + * @packet_id: checksum to identify packet + * + * Returns true if the packet was buffered or false in case of an error. + */ +static bool batadv_nc_skb_add_to_path(struct sk_buff *skb, + struct batadv_nc_path *nc_path, + struct batadv_neigh_node *neigh_node, + __be32 packet_id) +{ + struct batadv_nc_packet *nc_packet; + + nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC); + if (!nc_packet) + return false; + + /* Initialize nc_packet */ + nc_packet->timestamp = jiffies; + nc_packet->packet_id = packet_id; + nc_packet->skb = skb; + nc_packet->neigh_node = neigh_node; + nc_packet->nc_path = nc_path; + + /* Add coding packet to list */ + spin_lock_bh(&nc_path->packet_list_lock); + list_add_tail(&nc_packet->list, &nc_path->packet_list); + spin_unlock_bh(&nc_path->packet_list_lock); + + return true; +} + +/** + * batadv_nc_skb_forward - try to code a packet or add it to the coding packet + * buffer + * @skb: data skb to forward + * @neigh_node: next hop to forward packet to + * @ethhdr: pointer to the ethernet header inside the skb + * + * Returns true if the skb was consumed (encoded packet sent) or false otherwise + */ +bool batadv_nc_skb_forward(struct sk_buff *skb, + struct batadv_neigh_node *neigh_node, + struct ethhdr *ethhdr) +{ + const struct net_device *netdev = neigh_node->if_incoming->soft_iface; + struct batadv_priv *bat_priv = netdev_priv(netdev); + struct batadv_unicast_packet *packet; + struct batadv_nc_path *nc_path; + __be32 packet_id; + u8 *payload; + + /* Check if network coding is enabled */ + if (!atomic_read(&bat_priv->network_coding)) + goto out; + + /* We only handle unicast packets */ + payload = skb_network_header(skb); + packet = (struct batadv_unicast_packet *)payload; + if (packet->header.packet_type != BATADV_UNICAST) + goto out; + + /* Find or create a nc_path for this src-dst pair */ + nc_path = batadv_nc_get_path(bat_priv, + bat_priv->nc.coding_hash, + ethhdr->h_source, + neigh_node->addr); + + if (!nc_path) + goto out; + + /* Add skb to nc_path */ + packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet)); + if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id)) + goto free_nc_path; + + /* Packet is consumed */ + return true; + +free_nc_path: + batadv_nc_path_free_ref(nc_path); +out: + /* Packet is not consumed */ + return false; +} + +/** * batadv_nc_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) { 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); } /** @@ -492,6 +976,11 @@ int batadv_nc_init_debugfs(struct batadv_priv *bat_priv) if (!file) goto out; + file = debugfs_create_u32("max_fwd_delay", S_IRUGO | S_IWUSR, nc_dir, + &bat_priv->nc.max_fwd_delay); + if (!file) + goto out; + return 0; out: diff --git a/network-coding.h b/network-coding.h index 56dadfd..970dbde 100644 --- a/network-coding.h +++ b/network-coding.h @@ -35,6 +35,9 @@ void batadv_nc_purge_orig(struct batadv_priv *bat_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); +bool batadv_nc_skb_forward(struct sk_buff *skb, + struct batadv_neigh_node *neigh_node, + struct ethhdr *ethhdr); int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset); int batadv_nc_init_debugfs(struct batadv_priv *bat_priv); @@ -79,6 +82,13 @@ static inline void batadv_nc_init_orig(struct batadv_orig_node *orig_node) return; } +static inline bool batadv_nc_skb_forward(struct sk_buff *skb, + struct batadv_neigh_node *neigh_node, + struct ethhdr *ethhdr) +{ + return false; +} + static inline int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset) { diff --git a/routing.c b/routing.c index 1aa1722..d7bd4d1 100644 --- a/routing.c +++ b/routing.c @@ -29,6 +29,7 @@ #include "unicast.h" #include "bridge_loop_avoidance.h" #include "distributed-arp-table.h" +#include "network-coding.h" static int batadv_route_unicast_packet(struct sk_buff *skb, struct batadv_hard_iface *recv_if); @@ -855,14 +856,17 @@ static int batadv_route_unicast_packet(struct sk_buff *skb, /* decrement ttl */ unicast_packet->header.ttl--; - /* Update stats counter */ - batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD); - batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES, - skb->len + ETH_HLEN); - - /* route it */ - if (batadv_send_skb_to_orig(skb, orig_node, recv_if)) + /* network code packet if possible */ + if (batadv_nc_skb_forward(skb, neigh_node, ethhdr)) { ret = NET_RX_SUCCESS; + } else if (batadv_send_skb_to_orig(skb, orig_node, recv_if)) { + ret = NET_RX_SUCCESS; + + /* Update stats counter */ + batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD); + batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES, + skb->len + ETH_HLEN); + } out: if (neigh_node) diff --git a/types.h b/types.h index beb84f4..b34fde7 100644 --- a/types.h +++ b/types.h @@ -275,11 +275,19 @@ struct batadv_priv_dat { * struct batadv_priv_nc - per mesh interface network coding private data * @work: work queue callback item for cleanup * @min_tq: only consider neighbors for encoding if neigh_tq > min_tq + * @max_fwd_delay: maximum packet forward delay to allow coding of packets + * @timestamp_fwd_flush: timestamp of last forward packet queue flush + * @coding_hash: Hash table used to buffer skbs while waiting for another + * incoming skb to code it with. Skbs are added to the buffer just before being + * forwarded in routing.c */ struct batadv_priv_nc { struct delayed_work work; struct dentry *debug_dir; u8 min_tq; + u32 max_fwd_delay; + unsigned long timestamp_fwd_flush; + struct batadv_hashtable *coding_hash; }; /** @@ -441,6 +449,47 @@ struct batadv_nc_node { unsigned long last_seen; }; +/** + * struct batadv_nc_path - network coding path + * @hash_entry: next and prev pointer for the list handling + * @rcu: struct used for freeing in an RCU-safe manner + * @refcount: number of contexts the object is used by + * @packet_list: list of buffered packets for this path + * @packet_list_lock: access lock for packet list + * @next_hop: next hop (destination) of path + * @prev_hop: previous hop (source) of path + * @last_valid: timestamp for last validation of path + */ +struct batadv_nc_path { + struct hlist_node hash_entry; + struct rcu_head rcu; + atomic_t refcount; + struct list_head packet_list; + spinlock_t packet_list_lock; /* Protects packet_list */ + uint8_t next_hop[ETH_ALEN]; + uint8_t prev_hop[ETH_ALEN]; + unsigned long last_valid; +}; + +/** + * struct batadv_nc_packet - network coding packet used when coding and + * decoding packets + * @list: next and prev pointer for the list handling + * @packet_id: crc32 checksum of skb data + * @timestamp: field containing the info when the packet was added to path + * @neigh_node: pointer to original next hop neighbor of skb + * @skb: skb which can be encoded or used for decoding + * @nc_path: pointer to path this nc packet is attached to + */ +struct batadv_nc_packet { + struct list_head list; + __be32 packet_id; + unsigned long timestamp; + struct batadv_neigh_node *neigh_node; + struct sk_buff *skb; + struct batadv_nc_path *nc_path; +}; + /* forw_packet - structure for forw_list maintaining packets to be * send/forwarded */ -- 1.8.0.1

To be able to decode a network coded packet, a node must already know one of the two coded packets. This is done by buffering skbs before transmission and buffering packets sniffed with promiscuous mode from other hosts. Packets are kept in a buffer similar to the one with forward-skbs: A hash table, where each entry, which corresponds to a src-dst pair, has a linked list packets. Signed-off-by: Martin Hundebøll &lt;martin(a)hundeboll.net&gt; --- network-coding.c | 207 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- network-coding.h | 18 +++++ routing.c | 8 ++- send.c | 5 ++ soft-interface.c | 1 + types.h | 10 +++ 6 files changed, 247 insertions(+), 2 deletions(-) diff --git a/network-coding.c b/network-coding.c index ebbe0e9..3b603ae 100644 --- a/network-coding.c +++ b/network-coding.c @@ -27,6 +27,7 @@ #include "hard-interface.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); @@ -47,8 +48,9 @@ static void batadv_nc_start_timer(struct batadv_priv *bat_priv) int batadv_nc_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) + if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash) return 0; bat_priv->nc.coding_hash = batadv_hash_new(128); @@ -58,6 +60,13 @@ int batadv_nc_init(struct batadv_priv *bat_priv) batadv_hash_set_lock_class(bat_priv->nc.coding_hash, &batadv_nc_coding_hash_lock_class_key); + bat_priv->nc.decoding_hash = batadv_hash_new(128); + if (!bat_priv->nc.decoding_hash) + goto err; + + batadv_hash_set_lock_class(bat_priv->nc.coding_hash, + &batadv_nc_decoding_hash_lock_class_key); + INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker); batadv_nc_start_timer(bat_priv); return 0; @@ -75,6 +84,7 @@ void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv) atomic_set(&bat_priv->network_coding, 1); bat_priv->nc.min_tq = 200; bat_priv->nc.max_fwd_delay = 10; + bat_priv->nc.max_buffer_time = 200; } /** @@ -175,6 +185,26 @@ static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv, } /** + * batadv_nc_to_purge_nc_path_decoding - checks whether an nc path has timed out + * @bat_priv: the bat priv with all the soft interface information + * @nc_path: the nc path to check + * + * Returns true if the entry has to be purged now, false otherwise + */ +static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv, + struct batadv_nc_path *nc_path) +{ + if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE) + return true; + + /* purge the path when no packets has been added for 10 times the + * max_buffer time + */ + return batadv_has_timed_out(nc_path->last_valid, + bat_priv->nc.max_buffer_time*10); +} + +/** * batadv_nc_purge_orig_nc_nodes - go through list of nc nodes and purge stale * entries * @bat_priv: the bat priv with all the soft interface information @@ -443,6 +473,42 @@ static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet) } /** + * batadv_nc_sniffed_purge - 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. + * @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 + * + * Returns false as soon as the entry in the fifo queue has not been timed out + * yet and true otherwise. + */ +static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv, + struct batadv_nc_path *nc_path, + struct batadv_nc_packet *nc_packet) +{ + unsigned long timeout = bat_priv->nc.max_buffer_time; + bool res = false; + + /* Packets are added to tail, so the remaining packets did not time + * out and we can stop processing the current queue + */ + if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE && + !batadv_has_timed_out(nc_packet->timestamp, timeout)) + goto out; + + /* purge nc packet */ + list_del(&nc_packet->list); + batadv_nc_packet_free(nc_packet); + + res = true; + +out: + return res; +} + +/** * batadv_nc_fwd_flush - Checks 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. @@ -544,6 +610,8 @@ static void batadv_nc_worker(struct work_struct *work) 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; @@ -553,6 +621,13 @@ static void batadv_nc_worker(struct work_struct *work) 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); } @@ -1143,6 +1218,41 @@ batadv_nc_skb_src_search(struct batadv_priv *bat_priv, } /** + * batadv_nc_skb_store_before_coding - set the ethernet src and dst of the + * unicast skb before it is stored for use in later decoding + * @bat_priv: the bat priv with all the soft interface information + * @skb: data skb to store + * @eth_dst_new: new destination mac address of skb + */ +static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv, + struct sk_buff *skb, + uint8_t *eth_dst_new) +{ + struct ethhdr *ethhdr; + + /* Copy skb header to change the mac header */ + skb = pskb_copy(skb, GFP_ATOMIC); + if (!skb) + return; + + /* Set the mac header as if we actually sent the packet uncoded */ + ethhdr = (struct ethhdr *)skb_mac_header(skb); + memcpy(ethhdr->h_source, ethhdr->h_dest, ETH_ALEN); + memcpy(ethhdr->h_dest, eth_dst_new, ETH_ALEN); + + /* Set data pointer to MAC header to mimic packets from our tx path */ + skb_push(skb, ETH_HLEN); + + /* Add the packet to the decoding packet pool */ + batadv_nc_skb_store_for_decoding(bat_priv, skb); + + /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free + * our ref + */ + kfree_skb(skb); +} + +/** * batadv_nc_skb_dst_search - Loops through list of neighboring nodes 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 @@ -1179,6 +1289,12 @@ static bool batadv_nc_skb_dst_search(struct sk_buff *skb, 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)) @@ -1286,14 +1402,98 @@ out: } /** + * batadv_nc_skb_store_for_decoding - save a clone of the skb which can be used + * when decoding coded packets + * @bat_priv: the bat priv with all the soft interface information + * @skb: data skb to store + */ +void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + struct batadv_unicast_packet *packet; + struct batadv_nc_path *nc_path; + struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb); + __be32 packet_id; + u8 *payload; + + /* Check if network coding is enabled */ + if (!atomic_read(&bat_priv->network_coding)) + goto out; + + /* Check for supported packet type */ + payload = skb_network_header(skb); + packet = (struct batadv_unicast_packet *)payload; + if (packet->header.packet_type != BATADV_UNICAST) + goto out; + + /* Find existing nc_path or create a new */ + nc_path = batadv_nc_get_path(bat_priv, + bat_priv->nc.decoding_hash, + ethhdr->h_source, + ethhdr->h_dest); + + if (!nc_path) + goto out; + + /* Clone skb and adjust skb->data to point at batman header */ + skb = skb_clone(skb, GFP_ATOMIC); + if (unlikely(!skb)) + goto free_nc_path; + + if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) + goto free_skb; + + if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN))) + goto free_skb; + + /* Add skb to nc_path */ + packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet)); + if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id)) + goto free_skb; + + batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER); + return; + +free_skb: + kfree_skb(skb); +free_nc_path: + batadv_nc_path_free_ref(nc_path); +out: + return; +} + +/** + * batadv_nc_skb_store_sniffed_unicast - check if a received unicast packet + * should be saved in the decoding buffer and, if so, store it there + * @bat_priv: the bat priv with all the soft interface information + * @skb: unicast skb to store + */ +void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb); + + if (batadv_is_my_mac(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_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) { 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); } /** @@ -1375,6 +1575,11 @@ int batadv_nc_init_debugfs(struct batadv_priv *bat_priv) if (!file) goto out; + file = debugfs_create_u32("max_buffer_time", S_IRUGO | S_IWUSR, nc_dir, + &bat_priv->nc.max_buffer_time); + if (!file) + goto out; + return 0; out: diff --git a/network-coding.h b/network-coding.h index 970dbde..7b4140d 100644 --- a/network-coding.h +++ b/network-coding.h @@ -38,6 +38,10 @@ void batadv_nc_init_orig(struct batadv_orig_node *orig_node); bool batadv_nc_skb_forward(struct sk_buff *skb, struct batadv_neigh_node *neigh_node, struct ethhdr *ethhdr); +void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv, + struct sk_buff *skb); +void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv, + struct sk_buff *skb); int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset); int batadv_nc_init_debugfs(struct batadv_priv *bat_priv); @@ -89,6 +93,20 @@ static inline bool batadv_nc_skb_forward(struct sk_buff *skb, return false; } +static inline void +batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + return; +} + +static inline void +batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + return; +} + static inline int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset) { diff --git a/routing.c b/routing.c index d7bd4d1..59e1894 100644 --- a/routing.c +++ b/routing.c @@ -1053,8 +1053,14 @@ int batadv_recv_unicast_packet(struct sk_buff *skb, if (is4addr) hdr_size = sizeof(*unicast_4addr_packet); - if (batadv_check_unicast_packet(skb, hdr_size) < 0) + if (batadv_check_unicast_packet(skb, hdr_size) < 0) { + /* Even though the packet is to be dropped, we might save + * it to use for decoding a later received coded packet + */ + batadv_nc_skb_store_sniffed_unicast(bat_priv, skb); + return NET_RX_DROP; + } if (!batadv_check_unicast_ttvn(bat_priv, skb)) return NET_RX_DROP; diff --git a/send.c b/send.c index 4425af9..8482b85 100644 --- a/send.c +++ b/send.c @@ -27,6 +27,7 @@ #include "vis.h" #include "gateway_common.h" #include "originator.h" +#include "network-coding.h" #include <linux/if_ether.h> @@ -39,6 +40,7 @@ int batadv_send_skb_packet(struct sk_buff *skb, struct batadv_hard_iface *hard_iface, const uint8_t *dst_addr) { + struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface); struct ethhdr *ethhdr; if (hard_iface->if_status != BATADV_IF_ACTIVE) @@ -70,6 +72,9 @@ int batadv_send_skb_packet(struct sk_buff *skb, skb->dev = hard_iface->net_dev; + /* Save a clone of the skb to use when decoding coded packets */ + batadv_nc_skb_store_for_decoding(bat_priv, skb); + /* dev_queue_xmit() returns a negative result on error. However on * congestion and traffic shaping, it drops and returns NET_XMIT_DROP * (which is > 0). This will not be treated as an error. diff --git a/soft-interface.c b/soft-interface.c index 83abdf9..8f8a433 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -641,6 +641,7 @@ static const struct { { "nc_code_bytes" }, { "nc_recode" }, { "nc_recode_bytes" }, + { "nc_buffer" }, #endif }; diff --git a/types.h b/types.h index a44e948..90df980 100644 --- a/types.h +++ b/types.h @@ -197,6 +197,7 @@ enum batadv_counters { BATADV_CNT_NC_CODE_BYTES, BATADV_CNT_NC_RECODE, BATADV_CNT_NC_RECODE_BYTES, + BATADV_CNT_NC_BUFFER, #endif BATADV_CNT_NUM, }; @@ -282,18 +283,27 @@ struct batadv_priv_dat { * @work: work queue callback item for cleanup * @min_tq: only consider neighbors for encoding if neigh_tq > min_tq * @max_fwd_delay: maximum packet forward delay to allow coding of packets + * @max_buffer_time: buffer time for sniffed packets used to decoding * @timestamp_fwd_flush: timestamp of last forward packet queue flush + * @timestamp_sniffed_purge: timestamp of last sniffed packet queue purge * @coding_hash: Hash table used to buffer skbs while waiting for another * incoming skb to code it with. Skbs are added to the buffer just before being * forwarded in routing.c + * @decoding_hash: Hash table used to buffer skbs that might be needed to decode + * a received coded skb. The buffer is used for 1) skbs arriving on the + * soft-interface; 2) skbs overheard on the hard-interface; and 3) skbs + * forwarded by batman-adv. */ struct batadv_priv_nc { struct delayed_work work; struct dentry *debug_dir; u8 min_tq; u32 max_fwd_delay; + u32 max_buffer_time; unsigned long timestamp_fwd_flush; + unsigned long timestamp_sniffed_purge; struct batadv_hashtable *coding_hash; + struct batadv_hashtable *decoding_hash; }; /** -- 1.8.0.1

On Fri, Nov 30, 2012 at 04:08:33PM +0100, Martin Hundebøll wrote: is it batadv? ^^^ namespace: why didn't you put _nc_ here? is this computation worth a comment? with the short description I got "why", but it would be nice to understand "how", so that we don't forget in the future what we are doing here exactly? and here? we just have a discussion about assignment over multiple lines like this. It seems that David doesn't like it that much..please refactor it so that you don't have a two line assignment. + [...] what's the purpose of this cow()? might be? what if it is not? or it IS always so? Here I would suggest the same as the other description (in the other patch). Move the core of the description below and leave here just the flavour, in order to immediately grasp what this function is about, but without entering the details. [...] ehm.. :-) Cheers, -- Antonio Quartulli ..each of us alone is worth nothing.. Ernesto "Che" Guevara

On Sat, Dec 01, 2012 at 12:01:50PM +0100, Antonio Quartulli wrote: Sorry, I'm wrong here. Returning -ENOMEM will make the caller function proceed with the cleaning up. Therefore you can ignore this comment. Cheers, -- Antonio Quartulli ..each of us alone is worth nothing.. Ernesto "Che" Guevara