Commit Graph

37 Commits

Author SHA1 Message Date
Sven Eckelmann b2e55ca892 batman-adv: Disable CONFIG_BATMAN_ADV_SYSFS by default
The sysfs support in batman-adv is deprecated since a while and will be
removed completely next year.

All tools which were known to the batman-adv development team are
supporting the batman-adv netlink interface since a while. Thus
disabling CONFIG_BATMAN_ADV_SYSFS by default should not cause problems on
most systems. It is still possible to enable it in case it is still
required in a specific setup.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2020-01-01 00:57:07 +01:00
Sven Eckelmann 68e039f966 batman-adv: Update copyright years for 2020
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2020-01-01 00:00:33 +01:00
Krzysztof Kozlowski bf69abad27 net: Fix Kconfig indentation
Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
    $ sed -e 's/^        /\t/' -i */Kconfig

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-26 08:56:17 +02:00
Sven Eckelmann 0fa4c30d71 batman-adv: Make sysfs support optional
The sysfs files will be marked as deprecated in the near future. They are
already replaced by the batadv generic netlink family. Add an Kconfig
option to disable the sysfs support for users who want to test their tools
or want to safe some space. This setting should currently still be enabled
by default to keep backward compatible with legacy tools.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2019-03-25 10:01:11 +01:00
Sven Eckelmann 0d5f20c42b batman-adv: Drop license boilerplate
All files got a SPDX-License-Identifier with commit 7db7d9f369
("batman-adv: Add SPDX license identifier above copyright header"). All the
required information about the license conditions can be found in
LICENSES/.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2019-03-25 09:31:35 +01:00
Sven Eckelmann 7a79d717e0 batman-adv: Update copyright years for 2019
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2019-01-04 11:04:24 +01:00
Linus Lüssing 016fd28568 batman-adv: enable MCAST by default at compile time
Thanks to rigorous testing in wireless community mesh networks several
issues with multicast entries in the translation table were found and
fixed in the last 1.5 years. Now we see the first larger networks
(a few hundred nodes) with a batman-adv version with multicast
optimizations enabled arising, with no TT / multicast optimization
related issues so far.

Therefore it seems safe to enable multicast optimizations by default.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-11-12 10:41:51 +01:00
Sven Eckelmann fb939135a6 batman-adv: Move CRC16 dependency to BATMAN_ADV_BLA
The commit ced72933a5 ("batman-adv: use CRC32C instead of CRC16 in TT
code") switched the translation table code from crc16 to crc32c. The
(optional) bridge loop avoidance code is the only user of this function.

batman-adv should only select CRC16 when it is actually using it.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-11-12 10:41:51 +01:00
Sven Eckelmann 694127c1dd batman-adv: Fix description for BATMAN_ADV_DEBUG
The debug messages of batman-adv are not printed to the kernel log at all
but can be stored (depending on the compile setting) in the tracing buffer
or the batadv specific log buffer. There is also no debug module parameter
but a batadv netdev specific log_level setting to enable/disable different
classes of debug messages at runtime.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-11-12 10:41:50 +01:00
Sven Eckelmann 0dacc7fab6 batman-adv: Allow to use BATMAN_ADV_DEBUG without BATMAN_ADV_DEBUGFS
The BATMAN_ADV_DEBUGFS portion of batman-adv is marked as deprecated. Thus
all required functionality should be available without it. The debug log
was already modified to also output via the kernel tracing function but
still retained its BATMAN_ADV_DEBUGFS functionality.

Separate the entry point for the debug log from the debugfs portions to
make it possible to build with BATMAN_ADV_DEBUG and without
BATMAN_ADV_DEBUGFS.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-11-12 10:41:50 +01:00
Sven Eckelmann d331a73994 batman-adv: Provide debug messages as trace events
A private debug logging infrastructure is currently provided via
$debug_fs/batman_adv/*/log when CONFIG_BATMAN_ADV_DEBUG is enabled. This is
not well integrated in the rest of the tracing infrastructure of the
kernel.

Other components (like mac80211 or ath10k) allow to gather the debug
messages using generic trace events which are better integrated. This makes
it possible to interact with them using the existing userspace tools.

The tracepoint batadv:batadv_dbg will now be available when
CONFIG_BATMAN_ADV_DEBUG and CONFIG_BATMAN_ADV_TRACING is activated. The log
level mask is still used for filtering as usual.

A full system trace for offline parsing can be created (and read) using:

  $ batctl ll all
  $ trace-cmd record -e batadv:batadv_dbg
  $ trace-cmd report

The same can also be done without recording to a file

  $ batctl ll all
  $ trace-cmd stream -e batadv:batadv_dbg

The trace infrastructure is especially helpful when tracing processes:

  $ batctl ll all
  $ ./tools/perf/perf trace --event "batadv:*" batctl p 10.204.32.1
     0.000 batadv:batadv_dbg:batman_adv bat0 Parsing outgoing ARP REQUEST
     0.045 batadv:batadv_dbg:batman_adv bat0 ARP MSG = [src: a2:64:14:53:f8:22-10.204.32.185 dst: 00:00:00:00:00:00-10.204.32.1]
     0.067 batadv:batadv_dbg:batman_adv bat0 Entry updated: 10.204.32.185 a2:64:14:53:f8:22 (vid: -1)
     0.099 batadv:batadv_dbg:batman_adv bat0 batadv_dat_select_candidates(): IP=10.204.32.1 hash(IP)=48902
     0.757 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 0: selected fe:2c:91:68:29:2b addr=48977 dist=65460
     1.178 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 1: selected fe:81:ab:c5:e3:03 addr=49181 dist=65256
     1.809 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 2: selected 66:25:a7:48:37:fb addr=49328 dist=65109
     1.828 batadv:batadv_dbg:batman_adv bat0 DHT_SEND for 10.204.32.1

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-09-15 09:51:08 +02:00
Sven Eckelmann 55f949c4fa batman-adv: Remove "default n" in Kconfig
The "default n" is the default value for any bool or tristate Kconfig
setting. It is therefore not necessary to add it to a config entry.

Reported-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-06-23 10:30:06 +02:00
Antonio Quartulli ab4e58534d batman-adv: enable DAT by default at compile time
DAT (Distributed ARP Table) has been enabled by default
in the out-of-tree batman-adv kernel module for several
years already.
It can now be enabled in the kernel too.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-06-23 10:30:06 +02:00
Sven Eckelmann 951a06e78d batman-adv: Drop "experimental" from BATMAN_V Kconfig
The Kconfig option BATMAN_ADV_BATMAN_V is now enabled by default when the
BATMAN_ADV is enabled. A feature which is enabled by default for a module
should not be considered experimental.

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-06-23 10:30:06 +02:00
Marek Lindner 18cfb44cf1 batman-adv: enable B.A.T.M.A.N. V compilation by default
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Acked-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-05-14 09:31:17 +02:00
Sven Eckelmann 1ba93211e2 batman-adv: Disable CONFIG_BATMAN_ADV_DEBUGFS by default
All tools which were known to the batman-adv development team are
supporting the batman-adv netlink interface since a while. Also debugfs is
not supported for batman-adv interfaces in any non-default netns. Thus
disabling CONFIG_BATMAN_ADV_DEBUGFS by default should not cause problems on
most systems. It is still possible to enable it in case it is still
required in a specific setup.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-04-22 09:29:14 +02:00
Sven Eckelmann 6b1aea8cf2 batman-adv: Update copyright years for 2018
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-02-26 17:57:39 +01:00
Sven Eckelmann 9969ffa85f batman-adv: Add license header to Kconfig
The last remaining file without license notice and/or SPDX license
identifier under net/batman-adv/ is the Kconfig. It should have been
licensed under the same conditions as the rest of batman-adv and the
Makefile which uses the CONFIG_* variables from Kconfig.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-12-15 17:24:08 +01:00
Linus Lüssing 0566df307b batman-adv: Allow selecting BATMAN V if CFG80211 is not built
With the new stub for cfg80211_get_station(), we can now build the
BATMAN V protocol even with a kernel that was built without any
wireless support.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-10-17 16:28:48 +02:00
Sven Eckelmann dc1cbd145e batman-adv: Allow to disable debugfs support
The files provided by batman-adv via debugfs are currently converted to
netlink. Tools which are not yet converted to use the netlink interface may
still rely on the old debugfs files. But systems which already upgraded
their tools can save some space by disabling this feature. The default
configuration of batman-adv on amd64 can reduce the size of the module by
around 11% when this feature is disabled.

    $ size net/batman-adv/batman-adv.ko*
       text    data     bss     dec     hex filename
     150507   10395    4160  165062   284c6 net/batman-adv/batman-adv.ko.y
     137106    7099    2112  146317   23b8d net/batman-adv/batman-adv.ko.n

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-08-09 07:54:54 +02:00
Linus Lüssing 687937ab34 batman-adv: Add multicast optimization support for bridged setups
With this patch we are finally able to support multicast optimizations
in bridged setups, too. So far, if a bridge was added on top of a
soft-interface (e.g. bat0) the batman-adv multicast optimizations
needed to be disabled to avoid packetloss.

Current Linux bridge implementations and API can now provide us
with the so far missing information about interested but "remote"
multicast receivers behind bridge ports.

The Linux bridge performs the detection of remote participants
interested in multicast packets with its own and mature so
called IGMP and MLD snooping code and stores that in its
database. With the new API provided by the bridge batman-adv can
now simply hook into this database.

We then reliably announce the gathered multicast listeners to
other nodes through the batman-adv translation table.

Additionally, the Linux bridge provides us with the information about
whether an IGMP/MLD querier exists. If there is none then we need to
disable multicast optimizations as we cannot learn about multicast
listeners on external, bridged-in host then.

Tested-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-06-30 10:29:43 +02:00
Linus Lüssing bd2a979e53 batman-adv: Always flood IGMP/MLD reports
With this patch IGMP or MLD reports are always flooded. This is
necessary for the upcoming bridge integration to function without
multicast packet loss.

With the report handling so far bridges might miss interested multicast
listeners, leading to wrongly excluding ports from multicast packet
forwarding.

Currently we are treating IGMP/MLD reports, the messages bridges use to
learn about interested multicast listeners, just as any other multicast
packet: We try to send them to nodes matching its multicast destination.

Unfortunately, the destination address of reports of the older
IGMPv2/MLDv1 protocol families do not strictly adhere to their own
protocol: More precisely, the interested receiver, an IGMPv2 or MLDv1
querier, itself usually does not listen to the multicast destination
address of any reports.

Therefore with this patch we are simply excluding IGMP/MLD reports from
the multicast forwarding code path and keep flooding them. By that
any bridge receives them and can properly learn about listeners.

To avoid compatibility issues with older nodes not yet implementing this
report handling, we need to force them to flood reports: We do this by
bumping the multicast TVLV version to 2, effectively disabling their
multicast optimization.

Tested-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-06-30 10:29:43 +02:00
Arnd Bergmann fb653ebddc batman-adv: clarify CFG80211 dependency
The driver calls cfg80211_get_station, which may be part of a
module, so we must not enable BATMAN_ADV_BATMAN_V if
BATMAN_ADV=y and CFG80211=m:

net/built-in.o: In function `batadv_v_elp_get_throughput':
(text+0x5c62c): undefined reference to `cfg80211_get_station'

This clarifies the dependency to cover all combinations.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: c833484e5f ("batman-adv: ELP - compute the metric based on the estimated throughput")
Acked-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-02 13:45:47 -05:00
Antonio Quartulli c833484e5f batman-adv: ELP - compute the metric based on the estimated throughput
In case of wireless interface retrieve the throughput by
querying cfg80211. To perform this call a separate work
must be scheduled because the function may sleep and this
is not allowed within an RCU protected context (RCU in this
case is used to iterate over all the neighbours).

Use ethtool to retrieve information about an Ethernet link
like HALF/FULL_DUPLEX and advertised bandwidth (e.g.
100/10Mbps).

The metric is updated each time a new ELP packet is sent,
this way it is possible to timely react to a metric
variation which can imply (for example) a neighbour
disconnection.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
2016-02-29 16:25:06 +08:00
Linus Luessing d6f94d91f7 batman-adv: ELP - adding basic infrastructure
The B.A.T.M.A.N. protocol originally only used a single
message type (called OGM) to determine the link qualities to
the direct neighbors and spreading these link quality
information through the whole mesh. This procedure is
summarized on the BATMAN concept page and explained in
details in the RFC draft published in 2008.

This approach was chosen for its simplicity during the
protocol design phase and the implementation. However, it
also bears some drawbacks:

 *  Wireless interfaces usually come with some packet loss,
    therefore a higher broadcast rate is desirable to allow
    a fast reaction on flaky connections.
    Other interfaces of the same host might be connected to
    Ethernet LANs / VPNs / etc which rarely exhibit packet
    loss would benefit from a lower broadcast rate to reduce
    overhead.
 *  It generally is more desirable to detect local link
    quality changes at a faster rate than propagating all
    these changes through the entire mesh (the far end of
    the mesh does not need to care about local link quality
    changes that much). Other optimizations strategies, like
    reducing overhead, might be possible if OGMs weren't
    used for all tasks in the mesh at the same time.

As a result detecting local link qualities shall be handled
by an independent message type, ELP, whereas the OGM message
type remains responsible for flooding the mesh with these
link quality information and determining the overall path
transmit qualities.

Developed by Linus during a 6 months trainee study period in
Ascom (Switzerland) AG.

Signed-off-by: Linus Luessing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
2016-02-29 16:05:29 +08:00
Sven Eckelmann 7b5e739619 batman-adv: Switch to HTTPS version of links
open-mesh.org and its subdomains can only be accessed via HTTPS. HTTP-only
requests are currently redirected automatically to HTTPS but references in
the source code should be only https.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
2016-02-03 09:54:39 +08:00
Markus Pargmann 9535395640 batman-adv: Kconfig, Add missing DEBUG_FS dependency
BATMAN_ADV_DEBUG is using debugfs files for the debugging log. So it
depends on DEBUG_FS which is missing as dependency in the Kconfig file.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
2015-01-07 22:17:11 +01:00
Linus Lüssing c5caf4ef34 batman-adv: Multicast Listener Announcements via Translation Table
With this patch a node which has no bridge interface on top of its soft
interface announces its local multicast listeners via the translation
table.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
2014-03-22 09:18:56 +01:00
Martin Hundebøll d353d8d4d9 batman-adv: network coding - add the initial infrastructure code
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>
2013-03-13 22:53:48 +01:00
Sven Eckelmann 95a066d82c batman-adv: Add function to calculate crc32c for the skb payload
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
2012-11-21 12:35:41 +01:00
Antonio Quartulli 1722447482 batman-adv: Distributed ARP Table - add compile option
This patch makes it possible to decide whether to include DAT within the
batman-adv binary or not.
It is extremely useful when the user wants to reduce the size of the resulting
module by cutting off any not needed feature.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
2012-11-07 20:00:22 +01:00
Antonio Quartulli 5c3a0e5535 batman-adv: Distributed ARP Table - add ARP parsing functions
ARP messages are now parsed to make it possible to trigger special actions
depending on their types (snooping).

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
2012-11-07 20:00:20 +01:00
Simon Wunderlich 7a5cc24277 batman-adv: add bridge loop avoidance compile option
The define CONFIG_BATMAN_ADV_BLA switches the bridge loop avoidance
on - skip it, and the bridge loop avoidance is not compiled in.

This is useful if binary size should be saved or the feature is
not needed.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
2012-04-11 14:29:00 +02:00
Simon Wunderlich 23721387c4 batman-adv: add basic bridge loop avoidance code
This second version of the bridge loop avoidance for batman-adv
avoids loops between the mesh and a backbone (usually a LAN).

By connecting multiple batman-adv mesh nodes to the same ethernet
segment a loop can be created when the soft-interface is bridged
into that ethernet segment. A simple visualization of the loop
involving the most common case - a LAN as ethernet segment:

node1  <-- LAN  -->  node2
  |                   |
wifi   <-- mesh -->  wifi

Packets from the LAN (e.g. ARP broadcasts) will circle forever from
node1 or node2 over the mesh back into the LAN.

With this patch, batman recognizes backbone gateways, nodes which are
part of the mesh and backbone/LAN at the same time. Each backbone
gateway "claims" clients from within the mesh to handle them
exclusively. By restricting that only responsible backbone gateways
may handle their claimed clients traffic, loops are effectively
avoided.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
2012-04-11 14:28:58 +02:00
Antonio Quartulli 10e3cd6a25 batman-adv: clean up Kconfig
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
2012-04-11 14:28:58 +02:00
Antonio Quartulli a73105b8d4 batman-adv: improved client announcement mechanism
The client announcement mechanism informs every mesh node in the network
of any connected non-mesh client, in order to find the path towards that
client from any given point in the mesh.

The old implementation was based on the simple idea of appending a data
buffer to each OGM containing all the client MAC addresses the node is
serving. All other nodes can populate their global translation tables
(table which links client MAC addresses to node addresses) using this
MAC address buffer and linking it to the node's address contained in the
OGM. A node that wants to contact a client has to lookup the node the
client is connected to and its address in the global translation table.

It is easy to understand that this implementation suffers from several
issues:
 - big overhead (each and every OGM contains the entire list of
   connected clients)
 - high latencies for client route updates due to long OGM trip time and
   OGM losses

The new implementation addresses these issues by appending client
changes (new client joined or a client left) to the OGM instead of
filling it with all the client addresses each time. In this way nodes
can modify their global tables by means of "updates", thus reducing the
overhead within the OGMs.

To keep the entire network in sync each node maintains a translation
table version number (ttvn) and a translation table checksum. These
values are spread with the OGM to allow all the network participants to
determine whether or not they need to update their translation table
information.

When a translation table lookup is performed in order to send a packet
to a client attached to another node, the destination's ttvn is added to
the payload packet. Forwarding nodes can compare the packet's ttvn with
their destination's ttvn (this node could have a fresher information
than the source) and re-route the packet if necessary. This greatly
reduces the packet loss of clients roaming from one AP to the next.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-06-20 11:37:24 +02:00
Sven Eckelmann c6c8fea297 net: Add batman-adv meshing protocol
B.A.T.M.A.N. (better approach to mobile ad-hoc networking) is a routing
protocol for multi-hop ad-hoc mesh networks. The networks may be wired or
wireless. See http://www.open-mesh.org/ for more information and user space
tools.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-16 13:44:24 -08:00