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>
A delayed_work struct does not need to be initialized each
every time before being enqueued. Therefore the
INIT_DELAYED_WORK() macro should be used during the
initialization process only.
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
The current timeout is set to one hour. However a client connected to the mesh
network will always generate traffic. In the worst case it will send ARP
requests every 4 or 5 minutes. On the other hand having a long timeout means
storing dead entries for one hour and it leads to very big trans-tables
containing useless clients.
This patch reduces the timeout to 10 minutes
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
this_cpu_add is an atomic operation.
and be more faster than per_cpu_ptr operation.
Signed-off-by: Shan Wei <davidshan@tencent.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
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>
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>
For some reasons (bridge forward delay, network device setup order, etc)
the initial bridge loop avoidance announcement packets may be lost. This
may lead to problems in finding other backbone gws, and therfore create
loops in the startup time.
Fix this by extending the waiting periods to 3 (define can be changed)
before allowing broadcast traffic.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
In case of an ARP message going in or out the soft_iface, it is intercepted and
a special action is performed. In particular the DHT helper functions previously
implemented are used to store all the ARP entries belonging to the network in
order to provide a fast and unicast lookup instead of the classic broadcast
flooding mechanism.
Each node stores the entries it is responsible for (following the DHT rules) in
its soft_iface ARP table. This makes it possible to reuse the kernel data
structures and functions for ARP management.
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Since batman-adv cannot inter-operate with the host ARP table, this patch
introduces a batman-adv private storage for ARP entries exchanged within DAT.
This storage will represent the node local cache in the DAT protocol.
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Add all the relevant functions in order to manage a Distributed Hash Table over
the B.A.T.M.A.N.-adv network. It will later be used to store several ARP entries
and implement DAT (Distributed ARP Table)
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
A new log level has been added to concentrate messages regarding DAT: ARP
snooping, requests, response and DHT related messages.
The new log level is named BATADV_DBG_DAT
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
New operations should not be started when they need an increased module
reference counter and try_module_get failed.
This patch addresses Coverity #712284: Unchecked return value
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
With the current TT mechanism a new client joining the network is not
immediately able to communicate with other hosts because its MAC address has not
been announced yet. This situation holds until the first OGM containing its
joining event will be spread over the mesh network.
This behaviour can be acceptable in networks where the originator interval is a
small value (e.g. 1sec) but if that value is set to an higher time (e.g. 5secs)
the client could suffer from several malfunctions like DHCP client timeouts,
etc.
This patch adds an early detection mechanism that makes nodes in the network
able to recognise "not yet announced clients" by means of the broadcast packets
they emitted on connection (e.g. ARP or DHCP request). The added client will
then be confirmed upon receiving the OGM claiming it or purged if such OGM
is not received within a fixed amount of time.
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Fix incorrect start markers, wrapped summary lines, missing section
breaks, incorrect separators, and some name mismatches.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Acked-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
All non-static symbols of batman-adv were prefixed with batadv_ to avoid
collisions with other symbols of the kernel. Other symbols of batman-adv
should use the same prefix to keep the naming scheme consistent.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
batman-adv doesn't follow the style for multiline comments that David S. Miller
prefers. All comments should be reformatted to follow this consistent style to
make the code slightly more readable.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
batman-adv can be compiled as part of the kernel instead of an module. In that
case the linker will see all non-static symbols of batman-adv and all other
non-static symbols of the kernel. This could lead to symbol collisions. A
prefix for the batman-adv symbols that defines their private namespace avoids
such a problem.
Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
batman-adv can be compiled as part of the kernel instead of an module. In that
case the linker will see all non-static symbols of batman-adv and all other
non-static symbols of the kernel. This could lead to symbol collisions. A
prefix for the batman-adv symbols that defines their private namespace avoids
such a problem.
Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Added additional counters in a bat_stats structure, which are exported
through the ethtool api. The counters are specific to batman-adv and
includes:
forwarded packets and bytes
management packets and bytes (aggregated OGMs at this point)
translation table packets
New counters are added by extending "enum bat_counters" in types.h and
adding corresponding descriptive string(s) to bat_counters_strings in
soft-iface.c.
Counters are increased by calling batadv_add_counter() and incremented
by one by calling batadv_inc_counter().
Signed-off-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
The packet handler array replaces the growing switch statement, thus
dealing with incoming packets in a more efficient way. It also adds
to possibility to register packet handlers on the fly.
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Acked-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
When multiple backbone gateways relay the same broadcast from the
backbone into the mesh, other nodes in the mesh may receive this
broadcast multiple times. To avoid this, the crc checksums of
received broadcasts are recorded and new broadcast packets with
the same content may be dropped if received by another gateway.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
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>
The functionality is to be replaced by an improved implementation,
so first clean up.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
bitarray.c consists mostly of functionality that is already available as part
of the standard kernel API. batman-adv could use architecture optimized code
and reduce the binary size by switching to the standard functions.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
To increase readability the has_timed_out() functions has been introduced.
This patch converts existing time_after() calls to use this wrapper
function (if applicable).
This patch also converts all timeouts to miliseconds to be consistent.
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Both translation tables and network coding use timeouts to do house
keeping, so we might as well share the function used to compare a
timestamp+timeout with current time.
For readability and simplicity, the function is renamed to
has_timed_out() and uses time_is_before_jiffies() instead of
time_after().
Signed-off-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Clients connected through a 802.11 device are now marked with the
TT_CLIENT_WIFI flag. This flag is also advertised with the tt
announcement.
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Several typos have been corrected and some sentences have been rephrased
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
The version number of modules build outside of the tree can get revision
numbers added. This is useful to give hints about the revision of a
distribution package and the used patchset. The prepended source number or
branch name doesn't add any additional information which would help to identify
problems and can therefore be omitted.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
If a client issues a DHCPREQUEST for renewal, the packet is dropped
if the old destination (the old gateway for the client) TQ is smaller
than the current best gateway TQ less GW_THRESHOLD
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>
