Commit Graph

41 Commits

Author SHA1 Message Date
Sven Eckelmann bccb48c89f batman-adv: Fix typos and grammar in documentation
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2020-06-26 10:36:30 +02:00
Sven Eckelmann 9ad346c905 batman-adv: Revert "disable ethtool link speed detection when auto negotiation off"
The commit 8c46fcd783 ("batman-adv: disable ethtool link speed detection
when auto negotiation off") disabled the usage of ethtool's link_ksetting
when auto negotation was enabled due to invalid values when used with
tun/tap virtual net_devices. According to the patch, automatic measurements
should be used for these kind of interfaces.

But there are major flaws with this argumentation:

* automatic measurements are not implemented
* auto negotiation has nothing to do with the validity of the retrieved
  values

The first point has to be fixed by a longer patch series. The "validity"
part of the second point must be addressed in the same patch series by
dropping the usage of ethtool's link_ksetting (thus always doing automatic
measurements over ethernet).

Drop the patch again to have more default values for various net_device
types/configurations. The user can still overwrite them using the
batadv_hardif's BATADV_ATTR_THROUGHPUT_OVERRIDE.

Reported-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2020-05-26 09:23:33 +02:00
Sven Eckelmann 26893e7e92 batman-adv: Utilize prandom_u32_max for random [0, max) values
The kernel provides a function to create random values from 0 - (max-1)
since commit f337db64af ("random32: add prandom_u32_max and convert open
coded users"). Simply use this function to replace code sections which use
prandom_u32 and a handcrafted method to map it to the correct range.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
2020-04-21 10:07:31 +02:00
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
René Treffer 2b1aa5a4c6 batman-adv: ELP - use wifi tx bitrate as fallback throughput
Some wifi drivers (e.g. ath10k) provide per-station rx/tx values but no
estimated throughput. Setting a better estimate than the default 1 MBit
makes these devices work well with B.A.T.M.A.N. V.

Signed-off-by: René Treffer <treffer@measite.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2019-12-09 00:30:46 +01:00
David S. Miller f83f715195 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Minor comment merge conflict in mlx5.

Staging driver has a fixup due to the skb->xmit_more changes
in 'net-next', but was removed in 'net'.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-05 14:14:19 -07:00
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
Anders Roxell ca8c3b922e batman-adv: fix warning in function batadv_v_elp_get_throughput
When CONFIG_CFG80211 isn't enabled the compiler correcly warns about
'sinfo.pertid' may be unused. It can also happen for other error
conditions that it not warn about.

net/batman-adv/bat_v_elp.c: In function ‘batadv_v_elp_get_throughput.isra.0’:
include/net/cfg80211.h:6370:13: warning: ‘sinfo.pertid’ may be used
 uninitialized in this function [-Wmaybe-uninitialized]
  kfree(sinfo->pertid);
        ~~~~~^~~~~~~~

Rework so that we only release '&sinfo' if cfg80211_get_station returns
zero.

Fixes: 7d652669b6 ("batman-adv: release station info tidstats")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2019-03-25 09:31:19 +01:00
David S. Miller a655fe9f19 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
An ipvlan bug fix in 'net' conflicted with the abstraction away
of the IPV6 specific support in 'net-next'.

Similarly, a bug fix for mlx5 in 'net' conflicted with the flow
action conversion in 'net-next'.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-08 15:00:17 -08:00
Felix Fietkau 7d652669b6 batman-adv: release station info tidstats
With the addition of TXQ stats in the per-tid statistics the struct
station_info grew significantly. This resulted in stack size warnings
due to the structure itself being above the limit for the warnings.

To work around this, the TID array was allocated dynamically. Also a
function to free this content was introduced with commit 7ea3e110f2
("cfg80211: release station info tidstats where needed") but the necessary
changes were not provided for batman-adv's B.A.T.M.A.N. V implementation.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Fixes: 8689c051a2 ("cfg80211: dynamically allocate per-tid stats for station info")
[sven@narfation.org: add commit message]
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2019-01-25 09:04:41 +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
Sven Eckelmann f4156f9656 batman-adv: Use explicit tvlv padding for ELP packets
The announcement messages of batman-adv COMPAT_VERSION 15 have the
possibility to announce additional information via a dynamic TVLV part.
This part is optional for the ELP packets and currently not parsed by the
Linux implementation. Still out-of-tree versions are using it to transport
things like neighbor hashes to optimize the rebroadcast behavior.

Since the ELP broadcast packets are smaller than the minimal ethernet
packet, it often has to be padded. This is often done (as specified in
RFC894) with octets of zero and thus work perfectly fine with the TVLV
part (making it a zero length and thus empty). But not all ethernet
compatible hardware seems to follow this advice. To avoid ambiguous
situations when parsing the TVLV header, just force the 4 bytes (TVLV
length + padding) after the required ELP header to zero.

Fixes: d6f94d91f7 ("batman-adv: ELP - adding basic infrastructure")
Reported-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 10:41:29 +01:00
Marek Lindner 4c4af69008 batman-adv: fix hardif_neigh refcount on queue_work() failure
The hardif_neigh refcounter is to be decreased by the queued work and
currently is never decreased if the queue_work() call fails.
Fix by checking the queue_work() return value and decrease refcount
if necessary.

Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-09-07 08:14:26 +02:00
Sven Eckelmann 88d0895d0e batman-adv: Avoid probe ELP information leak
The probe ELPs for WiFi interfaces are expanded to contain at least
BATADV_ELP_MIN_PROBE_SIZE bytes. This is usually a lot more than the
number of bytes which the template ELP packet requires.

These extra padding bytes were not initialized and thus could contain data
which were previously stored at the same location. It is therefore required
to set it to some predefined or random values to avoid leaking private
information from the system transmitting these kind of packets.

Fixes: e4623c913508 ("batman-adv: Avoid probe ELP information leak")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-09-06 13:54:47 +02:00
Marek Lindner 8c46fcd783 batman-adv: disable ethtool link speed detection when auto negotiation off
Virtual interface drivers such as tun / tap interfaces, VLAN, etc tend
to initialize the interface throughput with some value for the sake of
having a throughput number to export via ethtool. This exported
throughput leaves batman-adv to conclude the interface throughput is
genuine (reflecting reality), thus no measurements are necessary.

Based on the observation that those interface types also tend to set
the link auto-negotiation to 'off', batman-adv shall check this
setting to differentiate between genuine link throughput information
and placeholders installed by virtual interfaces.

The "default throughput" setting exported via sysfs still allows to
configure the batman-adv throughput for the interface, thus disabling
the measurements.

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 09:30:57 +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 fec149f5d3 batman-adv: Convert packet.h to uapi header
The header file is used by different userspace programs to inject packets
or to decode sniffed packets. It should therefore be available to them as
userspace header.

Also other components in the kernel (like the flow dissector) require
access to the packet definitions to be able to decode ETH_P_BATMAN ethernet
packets.

Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21 15:35:53 -05:00
Sven Eckelmann 7e9a8c2ce7 batman-adv: Use parentheses in function kernel-doc
The documentation describing kernel-doc comments for functions ("How to
format kernel-doc comments") uses parentheses at the end of the function
name. Using this format allows to use a consistent style when adding
documentation to a function and when referencing this function in a
different kernel-doc section.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-12-15 17:29:20 +01:00
Sven Eckelmann b92b94ac73 batman-adv: include gfp.h for GFP_* defines
The linux/gfp.h provides the GFP_ATOMIC and GFP_KERNEL define. It should
therefore be included instead of linux/fs.h.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-12-15 17:24:10 +01:00
Sven Eckelmann 7db7d9f369 batman-adv: Add SPDX license identifier above copyright header
The "Linux kernel licensing rules" require that each file has a SPDX
license identifier as first line (and sometimes as second line).

The FSFE REUSE practices [1] would also require the same tags but have no
restrictions on the placement in the source file. Using the "Linux kernel
licensing rules" is therefore also fulfilling the FSFE REUSE practices
requirements at the same time.

[1] https://reuse.software/practices/

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-12-15 17:22:45 +01:00
Sven Eckelmann 825ffe1f7b batman-adv: Remove unnecessary parentheses
checkpatch introduced with commit 63b7c73ec8 ("checkpatch: add --strict
check for ifs with unnecessary parentheses") an additional test which
identifies some unnecessary parentheses.

Remove these unnecessary parentheses to avoid the warnings and to unify the
coding style slightly more.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-09-28 17:20:45 +02:00
Johannes Berg b080db5853 networking: convert many more places to skb_put_zero()
There were many places that my previous spatch didn't find,
as pointed out by yuan linyu in various patches.

The following spatch found many more and also removes the
now unnecessary casts:

    @@
    identifier p, p2;
    expression len;
    expression skb;
    type t, t2;
    @@
    (
    -p = skb_put(skb, len);
    +p = skb_put_zero(skb, len);
    |
    -p = (t)skb_put(skb, len);
    +p = skb_put_zero(skb, len);
    )
    ... when != p
    (
    p2 = (t2)p;
    -memset(p2, 0, len);
    |
    -memset(p, 0, len);
    )

    @@
    type t, t2;
    identifier p, p2;
    expression skb;
    @@
    t *p;
    ...
    (
    -p = skb_put(skb, sizeof(t));
    +p = skb_put_zero(skb, sizeof(t));
    |
    -p = (t *)skb_put(skb, sizeof(t));
    +p = skb_put_zero(skb, sizeof(t));
    )
    ... when != p
    (
    p2 = (t2)p;
    -memset(p2, 0, sizeof(*p));
    |
    -memset(p, 0, sizeof(*p));
    )

    @@
    expression skb, len;
    @@
    -memset(skb_put(skb, len), 0, len);
    +skb_put_zero(skb, len);

Apply it to the tree (with one manual fixup to keep the
comment in vxlan.c, which spatch removed.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-16 11:48:35 -04:00
Sven Eckelmann d62890885e batman-adv: Accept only filled wifi station info
The wifi driver can decide to not provide parts of the station info. For
example, the expected throughput of the station can be omitted when the
used rate control doesn't provide this kind of information.

The B.A.T.M.A.N. V implementation must therefore check the filled bitfield
before it tries to access the expected_throughput of the returned
station_info.

Reported-by: Alvaro Antelo <alvaro.antelo@gmail.com>
Fixes: c833484e5f ("batman-adv: ELP - compute the metric based on the estimated throughput")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Reviewed-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-06-13 12:25:43 +02:00
Sven Eckelmann 3f3f87325d batman-adv: Use default throughput value on cfg80211 error
A wifi interface should never be handled like an ethernet devices. The
parser of the cfg80211 output must therefore skip the ethtool code when
cfg80211_get_station returned an error.

Fixes: f44a3ae9a2 ("batman-adv: refactor wifi interface detection")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Reviewed-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-06-13 12:24:02 +02:00
Sven Eckelmann ac79cbb96b batman-adv: update copyright years for 2017
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-01-26 08:34:19 +01:00
Marek Lindner 1942de1bba batman-adv: retrieve B.A.T.M.A.N. V WiFi neighbor stats from real interface
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
[sven.eckelmann@open-mesh.com: re-add batadv_get_real_netdev to take rtnl
 semaphore for batadv_get_real_netdevice]
Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-11-08 19:02:38 +01:00
Sven Eckelmann 10b1bbb46c batman-adv: Cache the type of wifi device for each hardif
batman-adv is requiring the type of wifi device in different contexts. Some
of them can take the rtnl semaphore and some of them already have the
semaphore taken. But even others don't allow that the semaphore will be
taken.

The data has to be retrieved when the hardif is added to batman-adv because
some of the wifi information for an hardif will only be available with rtnl
lock. It can then be cached in the batadv_hard_iface and the functions
is_wifi_netdev and is_cfg80211_netdev can just compare the correct bits
without imposing extra locking requirements.

Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-11-08 19:02:37 +01:00
Marek Lindner f44a3ae9a2 batman-adv: refactor wifi interface detection
The ELP protocol requires cfg80211 to auto-detect the WiFi througput
to a given neighbor. Use batadv_is_cfg80211_netdev() to determine
whether or not an interface is eligible.

Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-11-08 19:02:37 +01:00
Sven Eckelmann b91a2543b4 batman-adv: Consume skb in receive handlers
Receiving functions in Linux consume the supplied skbuff. Doing the same in
the batadv_rx_handler functions makes the behavior more similar to the rest
of the Linux network code.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-11-08 19:02:34 +01:00
Linus Lüssing 1e5d343b8f batman-adv: fix elp packet data reservation
The skb_reserve() call only reserved headroom for the mac header, but
not the elp packet header itself.

Fixing this by using skb_put()'ing towards the skb tail instead of
skb_push()'ing towards the skb head.

Fixes: d6f94d91f7 ("batman-adv: ELP - adding basic infrastructure")
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>
2016-08-26 15:22:31 +02:00
Antonio Quartulli 29824a55c0 batman-adv: split routing API data structure in subobjects
The routing API data structure contains several function
pointers that can easily be grouped together based on the
component they work with.

Split the API in subobjects in order to improve definition readability.

At the same time, remove the "bat_" prefix from the API object and
its fields names. These are batman-adv private structs and there is no
need to always prepend such prefix, which only makes function invocations
much much longer.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
Reviewed-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-07-04 12:37:19 +02:00
Sven Eckelmann ba412080fb batman-adv: Consolidate logging related functions
There are several places in batman-adv which provide logging related
functions. These should be grouped together in the log.* files to make them
easier to find.

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: Simon Wunderlich <sw@simonwunderlich.de>
2016-06-30 10:29:43 +02:00
Marek Lindner 7db682d1c3 batman-adv: init ELP tweaking options only once
The ELP interval and throughput override interface settings are initialized
with default settings on every time an interface is added to a mesh.
This patch prevents this behavior by moving the configuration init to the
interface detection routine which runs only once per interface.

Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
[a@unstable.cc: move initialization to batadv_v_hardif_init]
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2016-06-30 10:29:43 +02:00
Marek Lindner 6f0a6b5ee8 batman-adv: refactor batadv_neigh_node_* functions to follow common style
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
Marek Lindner ebe24cea95 batman-adv: initialize ELP orig address on secondary interfaces
This fix prevents nodes to wrongly create a 00:00:00:00:00:00 originator
which can potentially interfere with the rest of the neighbor statistics.

Fixes: d6f94d91f7 ("batman-adv: ELP - adding basic infrastructure")
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
2016-05-18 11:49:44 +08:00
Antonio Quartulli 8d2d499e08 batman-adv: ELP - send unicast ELP packets for throughput sampling
In case of an unused wireless link, the mac80211 throughput estimation
won't get updated further. Consequently, the reported throughput metric
will become obsolete.

With this patch unicast sampling is introduced by periodically sending
unicast ELP packets to each neighbor on idle WiFi links. These sampling
packets will fill an entire frame, so that the measurement is as
reliable as possible

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
2016-02-29 16:25:07 +08:00
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
Antonio Quartulli 95d392784d batman-adv: keep track of when unicast packets are sent
To enable ELP to send probing packets over wireless links
only if needed, batman-adv must keep track of the last time
it sent a unicast packet towards every neighbour.

For this purpose a 2 main changes are introduced:
1) a new member of the elp_neigh_node structure stores the
   last time a unicast packet was sent towards this neighbour;
2) a wrapper function for sending unicast packets is
   implemented. This function will simply update the member
   describe din point 1) and then forward the packet to the
   real sending routine.

Point 2) implies that any code-path leading to a unicast
sending now has to use the new wrapper.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
2016-02-29 16:05:32 +08:00
Antonio Quartulli 9323158ef9 batman-adv: OGMv2 - implement originators logic
Add the support for recognising new originators in the
network and rebroadcast their OGMs.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
2016-02-29 16:05:31 +08:00
Linus Luessing 162bd64c24 batman-adv: ELP - creating neighbor structures
Initially 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 16:05:30 +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