summaryrefslogtreecommitdiffstats
path: root/net/batman-adv/network-coding.c
Commit message (Collapse)AuthorAgeFilesLines
* batman-adv: Fix kerneldoc of network-coding functionsSven Eckelmann2016-02-021-0/+13
| | | | | | Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <a@unstable.cc>
* batman-adv: Fix kerneldoc parsing of return descriptionSven Eckelmann2016-02-021-21/+21
| | | | | | Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <a@unstable.cc>
* batman-adv: Avoid recursive call_rcu for batadv_nc_nodeSven Eckelmann2016-01-161-11/+8
| | | | | | | | | | | | | | | | | | | | | | The batadv_nc_node_free_ref function uses call_rcu to delay the free of the batadv_nc_node object until no (already started) rcu_read_lock is enabled anymore. This makes sure that no context is still trying to access the object which should be removed. But batadv_nc_node also contains a reference to orig_node which must be removed. The reference drop of orig_node was done in the call_rcu function batadv_nc_node_free_rcu but should actually be done in the batadv_nc_node_release function to avoid nested call_rcus. This is important because rcu_barrier (e.g. batadv_softif_free or batadv_exit) will not detect the inner call_rcu as relevant for its execution. Otherwise this barrier will most likely be inserted in the queue before the callback of the first call_rcu was executed. The caller of rcu_barrier will therefore continue to run before the inner call_rcu callback finished. Fixes: d56b1705e28c ("batman-adv: network coding - detect coding nodes and remove these after timeout") Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <a@unstable.cc>
* batman-adv: Delete unnecessary checks before the function call "kfree_skb"Markus Elfring2016-01-091-3/+1
| | | | | | | | | | | The kfree_skb() function tests whether its argument is NULL and then returns immediately. Thus the test around the calls is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <a@unstable.cc>
* batman-adv: Annotate deleting functions with external lock via lockdepSven Eckelmann2015-08-251-0/+4
| | | | | | | | | | | | | | Functions which use (h)list_del* are requiring correct locking when they operate on global lists. Most of the time the search in the list and the delete are done in the same function. All other cases should have it visible that they require a special lock to avoid race conditions. Lockdep asserts can be used to check these problem during runtime when the lockdep functionality is enabled. Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: Remove multiple assignment per lineSven Eckelmann2015-08-251-1/+2
| | | | | | | | | | The Linux CodingStyle disallows multiple assignments in a single line. (see chapter 1) Reported-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: Fix kerneldoc over 80 column linesSven Eckelmann2015-08-251-2/+2
| | | | | | | | | | | Kerneldoc required single line documentation in the past (before 2009). Therefore, the 80 columns limit per line check of checkpatch was disabled for kerneldoc. But kerneldoc is not excluded anymore from it and checkpatch now enabled the check again. Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: Replace C99 int types with kernel typeSven Eckelmann2015-08-251-23/+21
| | | | | | | | | | (s|u)(8|16|32|64) are the preferred types in the kernel. The use of the standard C99 types u?int(8|16|32|64)_t are objected by some people and even checkpatch now warns about using them. Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: Make NC capability changes atomicLinus Lüssing2015-08-141-3/+4
| | | | | | | | | | | | | Bitwise OR/AND assignments in C aren't guaranteed to be atomic. One OGM handler might undo the set/clear of a specific bit from another handler run in between. Fix this by using the atomic set_bit()/clear_bit()/test_bit() functions. Fixes: 3f4841ffb336 ("batman-adv: tvlv - add network coding container") Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: Add required includes to all filesSven Eckelmann2015-06-071-4/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The header files could not be build indepdent from each other. This is happened because headers didn't include the files for things they've used. This was problematic because the success of a build depended on the knowledge about the right order of local includes. Also source files were not including everything they've used explicitly. Instead they required that transitive includes are always stable. This is problematic because some transitive includes are not obvious, depend on config settings and may not be stable in the future. The order for include blocks are: * primary headers (main.h and the *.h file of a *.c file) * global linux headers * required local headers * extra forward declarations for pointers in function/struct declarations The only exceptions are linux/bitops.h and linux/if_ether.h in packet.h. This header file is shared with userspace applications like batctl and must therefore build together with userspace applications. The header linux/bitops.h is not part of the uapi headers and linux/if_ether.h conflicts with the musl implementation of netinet/if_ether.h. The maintainers rejected the use of __KERNEL__ preprocessor checks and thus these two headers are only in main.h. All files using packet.h first have to include main.h to work correctly. Reported-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: Use common Jenkins Hash implementationSven Eckelmann2015-06-071-8/+2
| | | | | | | | | | | | | An unoptimized version of the Jenkins one-at-a-time hash function is used and partially copied all over the code wherever an hashtable is used. Instead the optimized version shared between the whole kernel should be used to reduce code duplication and use better optimized code. Only the DAT code must use the old implementation because it is used as distributed hash function which has to be common for all nodes. Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: checkpatch - spaces preferred around that '*'Marek Lindner2015-05-291-1/+1
| | | | Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: Use safer default config for optional featuresSven Eckelmann2015-05-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current default settings for optional features in batman-adv seems to be based around the idea that the user only compiles what he requires. They will automatically enabled when they are compiled in. For example the network coding part of batman-adv is by default disabled in the out-of-tree module but will be enabled when the code is compiled during the module build. But distributions like Debian just enable all features of the batman-adv kernel module and hope that more experimental features or features with possible negative effects have to be enabled using some runtime configuration interface. The network_coding feature can help in specific setups but also has drawbacks and is not disabled by default in the out-of-tree module. Disabling by default in the runtime config seems to be also quite sane. The bridge_loop_avoidance is the only feature which is disabled by default but may be necessary even in simple setups. Packet loops may even be created during the initial node setup when this is not enabled. This is different than STP on bridges because mesh is usually used on Adhoc WiFi. Having two nodes (by accident) in the same LAN segment and in the same mesh network is rather common in this situation. Signed-off-by: Sven Eckelmann <sven@narfation.org> Acked-by: Martin Hundebøll <martin@hundeboll.net> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: update copyright years for 2015Sven Eckelmann2015-05-291-1/+1
| | | | | Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: checkpatch - else is not generally useful after a break or returnAntonio Quartulli2015-01-071-2/+1
| | | | | Signed-off-by: Antonio Quartulli <antonio@meshcoding.com> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: fix lock class for decoding hash in network-coding.cMartin Hundebøll2015-01-061-1/+1
| | | | | | | | | | | | | batadv_has_set_lock_class() is called with the wrong hash table as first argument (probably due to a copy-paste error), which leads to false positives when running with lockdep. Introduced-by: 612d2b4fe0a1ff2f8389462a6f8be34e54124c05 ("batman-adv: network coding - save overheard and tx packets for decoding") Signed-off-by: Martin Hundebøll <martin@hundeboll.net> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* net: add __pskb_copy_fclone and pskb_copy_for_cloneOctavian Purdila2014-06-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are several instances where a pskb_copy or __pskb_copy is immediately followed by an skb_clone. Add a couple of new functions to allow the copy skb to be allocated from the fclone cache and thus speed up subsequent skb_clone calls. Cc: Alexander Smirnov <alex.bluesman.smirnov@gmail.com> Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> Cc: Marek Lindner <mareklindner@neomailbox.ch> Cc: Simon Wunderlich <sw@simonwunderlich.de> Cc: Antonio Quartulli <antonio@meshcoding.com> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: Arvid Brodin <arvid.brodin@alten.se> Cc: Patrick McHardy <kaber@trash.net> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org> Cc: Aloisio Almeida Jr <aloisio.almeida@openbossa.org> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Jon Maloy <jon.maloy@ericsson.com> Cc: Allan Stephens <allan.stephens@windriver.com> Cc: Andrew Hendry <andrew.hendry@gmail.com> Cc: Eric Dumazet <edumazet@google.com> Reviewed-by: Christoph Paasch <christoph.paasch@uclouvain.be> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* batman-adv: add blank line between declarations and the rest of the codeAntonio Quartulli2014-05-181-0/+1
| | | | | | | | Reported by checkpatch with the following message: "WARNING: Missing a blank line after declarations" Signed-off-by: Antonio Quartulli <antonio@meshcoding.com> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: prefer ether_addr_copy to memcpyAntonio Quartulli2014-03-221-12/+12
| | | | | | | | On some architectures ether_addr_copy() is slightly faster than memcpy() therefore use the former when possible. Signed-off-by: Antonio Quartulli <antonio@meshcoding.com> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: fix coccinelle warningsFengguang Wu2014-03-221-1/+1
| | | | | | | | | | net/batman-adv/network-coding.c:1535:1-7: Replace memcpy with struct assignment Generated by: coccinelle/misc/memcpy-assign.cocci Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Martin Hundebøll <martin@hundeboll.net> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: update copyright years for 2014Simon Wunderlich2014-01-121-1/+1
| | | | | | Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: split out router from orig_nodeSimon Wunderlich2014-01-121-4/+21
| | | | | | | | | | | | | | For the network wide multi interface optimization there are different routers for each outgoing interface (outgoing from the OGM perspective, incoming for payload traffic). To reflect this, change the router and associated data to a list of routers. While at it, rename batadv_orig_node_get_router() to batadv_orig_router_get() to follow the new naming scheme. Signed-off-by: Simon Wunderlich <simon@open-mesh.com> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: split tq information in neigh_node structSimon Wunderlich2014-01-121-4/+20
| | | | | | | | | | | | | | For the network wide multi interface optimization it is required to save metrics per outgoing interface in one neighbor. Therefore a new type is introduced to keep interface-specific information. This also requires some changes in access and list management. The compare and equiv_or_better API calls are changed to take the outgoing interface into consideration. Signed-off-by: Simon Wunderlich <simon@open-mesh.com> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: remove FSF address from GPL disclaimerAntonio Quartulli2014-01-081-3/+1
| | | | | | | | | | | | As suggested by checkpatch, remove all the references to the FSF address since the kernel already has one reference in its documentation. In this way it is easier to update it in case of future changes. Signed-off-by: Antonio Quartulli <antonio@meshcoding.com> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
* batman-adv: fix header alignment by unrolling batadv_headerSimon Wunderlich2013-12-281-11/+11
| | | | | | | | | | | | The size of the batadv_header of 3 is problematic on some architectures which automatically pad all structures to a 32 bit boundary. To not lose performance by packing this struct, better embed it into the various host structures. Reported-by: Russell King <linux@arm.linux.org.uk> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: make struct batadv_neigh_node algorithm agnosticAntonio Quartulli2013-10-231-3/+5
| | | | | | | | | | some of the fields in struct batadv_neigh_node are strictly related to the B.A.T.M.A.N. IV algorithm. In order to make the struct usable by any routing algorithm it has to be split and made more generic Signed-off-by: Antonio Quartulli <antonio@open-mesh.com> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
* batman-adv: tvlv - add network coding containerMarek Lindner2013-10-091-0/+63
| | | | | | | | Create network coding container to announce network coding capabilities (if enabled). Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: set up network coding packet handlers during module initMatthias Schiffer2013-10-021-10/+18
| | | | | | | | | | | | | | | | | | batman-adv saves its table of packet handlers as a global state, so handlers must be set up only once (and setting them up a second time will fail). The recently-added network coding support tries to set up its handler each time a new softif is registered, which obviously fails when more that one softif is used (and in consequence, the softif creation fails). Fix this by splitting up batadv_nc_init into batadv_nc_init (which is called only once) and batadv_nc_mesh_init (which is called for each softif); in addition batadv_nc_free is renamed to batadv_nc_mesh_free to keep naming consistent. Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net> Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
* batman-adv: Move call to batadv_nc_skb_forward() from routing.c to send.cMartin Hundebøll2013-05-291-3/+2
| | | | | | | | | | | | | | The call to batadv_nc_skb_forward() fits better in batadv_send_skb_to_orig(), as this is where the actual next hop is looked up. To let the caller of batadv_send_skb_to_orig() know wether the skb is transmitted, buffered or failed, the return value is changed from boolean to int. Signed-off-by: Martin Hundebøll <martin@hundeboll.net> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* batman-adv: do not print orig nodes without nc neighbors on nc table printMarek Lindner2013-05-291-0/+7
| | | | | Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* batman-adv: use eth_hdr() when it makes senseAntonio Quartulli2013-05-291-5/+5
| | | | | | | | | Instead of casting the result of skb_mac_header() to "struct ethhdr *" every time, the eth_hdr inline function can be use to beautify the code and improve its readability. Signed-off-by: Antonio Quartulli <ordex@autistici.org> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
* batman-adv: check return value of pskb_trim_rcsum()Marek Lindner2013-05-091-2/+6
| | | | | | | Reported-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Acked-by: Martin Hundebøll <martin@hundeboll.net> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2013-04-221-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: drivers/net/ethernet/emulex/benet/be_main.c drivers/net/ethernet/intel/igb/igb_main.c drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c include/net/scm.h net/batman-adv/routing.c net/ipv4/tcp_input.c The e{uid,gid} --> {uid,gid} credentials fix conflicted with the cleanup in net-next to now pass cred structs around. The be2net driver had a bug fix in 'net' that overlapped with the VLAN interface changes by Patrick McHardy in net-next. An IGB conflict existed because in 'net' the build_skb() support was reverted, and in 'net-next' there was a comment style fix within that code. Several batman-adv conflicts were resolved by making sure that all calls to batadv_is_my_mac() are changed to have a new bat_priv first argument. Eric Dumazet's TS ECR fix in TCP in 'net' conflicted with the F-RTO rewrite in 'net-next', mostly overlapping changes. Thanks to Stephen Rothwell and Antonio Quartulli for help with several of these merge resolutions. Signed-off-by: David S. Miller <davem@davemloft.net>
* batman-adv: use seq_puts instead of seq_printf when the format is constantAntonio Quartulli2013-03-271-4/+4
| | | | | | | | | As reported by checkpatch, seq_puts has to be preferred with respect to seq_printf when the format is a constant string (no va_args) Signed-off-by: Antonio Quartulli <ordex@autistici.org> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
* batman-adv: Fix endianness errors for network codingMartin Hundebøll2013-03-271-1/+1
| | | | | | | | | | | | | | | | | | Add a htonl() in network_coding.c when reading the sequence number from received ogm_packet, to avoid wrong byte ordering when comparing with a host value. This bug was introduced in 3ed7ada3f0bbcd058567bc0a8f9729a73eba7db6 ("batman-adv: network coding - detect coding nodes and remove these after timeout"). Change the type of coded_packet->coded_len from uint16 to __be16 to avoid wrong assumptions about endianness in later uses. Introduced in c3289f3650d34b60296000a629c99f2488f7c3dd ("batman-adv: network coding - code and transmit packets if possible"). Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Martin Hundebøll <martin@hundeboll.net> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* batman-adv: network coding - receive coded packets and decode themMartin Hundebøll2013-03-131-0/+232
| | | | | | | | | | | | 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> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* batman-adv: network coding - save overheard and tx packets for decodingMartin Hundebøll2013-03-131-1/+207
| | | | | | | | | | | | | | | 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 <martin@hundeboll.net> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* batman-adv: network coding - code and transmit packets if possibleMartin Hundebøll2013-03-131-0/+401
| | | | | | | | | | | | | | | | | 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> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* batman-adv: network coding - buffer unicast packets before forwardMartin Hundebøll2013-03-131-0/+487
| | | | | | | | | | | | | | | | | 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 <martin@hundeboll.net> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* batman-adv: network coding - detect coding nodes and remove these after timeoutMartin Hundebøll2013-03-131-0/+414
| | | | | | | | | | | | | | | | | | | | | | | | 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> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
* batman-adv: network coding - add the initial infrastructure codeMartin Hundebøll2013-03-131-0/+81
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 <martin@hundeboll.net> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
OpenPOWER on IntegriCloud