169 строки
5.6 KiB
ReStructuredText
169 строки
5.6 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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==========
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batman-adv
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==========
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Batman advanced is a new approach to wireless networking which does no longer
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operate on the IP basis. Unlike the batman daemon, which exchanges information
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using UDP packets and sets routing tables, batman-advanced operates on ISO/OSI
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Layer 2 only and uses and routes (or better: bridges) Ethernet Frames. It
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emulates a virtual network switch of all nodes participating. Therefore all
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nodes appear to be link local, thus all higher operating protocols won't be
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affected by any changes within the network. You can run almost any protocol
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above batman advanced, prominent examples are: IPv4, IPv6, DHCP, IPX.
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Batman advanced was implemented as a Linux kernel driver to reduce the overhead
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to a minimum. It does not depend on any (other) network driver, and can be used
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on wifi as well as ethernet lan, vpn, etc ... (anything with ethernet-style
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layer 2).
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Configuration
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=============
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Load the batman-adv module into your kernel::
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$ insmod batman-adv.ko
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The module is now waiting for activation. You must add some interfaces on which
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batman-adv can operate. The batman-adv soft-interface can be created using the
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iproute2 tool ``ip``::
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$ ip link add name bat0 type batadv
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To activate a given interface simply attach it to the ``bat0`` interface::
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$ ip link set dev eth0 master bat0
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Repeat this step for all interfaces you wish to add. Now batman-adv starts
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using/broadcasting on this/these interface(s).
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To deactivate an interface you have to detach it from the "bat0" interface::
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$ ip link set dev eth0 nomaster
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The same can also be done using the batctl interface subcommand::
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batctl -m bat0 interface create
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batctl -m bat0 interface add -M eth0
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To detach eth0 and destroy bat0::
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batctl -m bat0 interface del -M eth0
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batctl -m bat0 interface destroy
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There are additional settings for each batadv mesh interface, vlan and hardif
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which can be modified using batctl. Detailed information about this can be found
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in its manual.
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For instance, you can check the current originator interval (value
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in milliseconds which determines how often batman-adv sends its broadcast
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packets)::
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$ batctl -M bat0 orig_interval
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1000
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and also change its value::
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$ batctl -M bat0 orig_interval 3000
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In very mobile scenarios, you might want to adjust the originator interval to a
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lower value. This will make the mesh more responsive to topology changes, but
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will also increase the overhead.
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Information about the current state can be accessed via the batadv generic
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netlink family. batctl provides a human readable version via its debug tables
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subcommands.
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Usage
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=====
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To make use of your newly created mesh, batman advanced provides a new
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interface "bat0" which you should use from this point on. All interfaces added
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to batman advanced are not relevant any longer because batman handles them for
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you. Basically, one "hands over" the data by using the batman interface and
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batman will make sure it reaches its destination.
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The "bat0" interface can be used like any other regular interface. It needs an
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IP address which can be either statically configured or dynamically (by using
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DHCP or similar services)::
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NodeA: ip link set up dev bat0
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NodeA: ip addr add 192.168.0.1/24 dev bat0
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NodeB: ip link set up dev bat0
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NodeB: ip addr add 192.168.0.2/24 dev bat0
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NodeB: ping 192.168.0.1
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Note: In order to avoid problems remove all IP addresses previously assigned to
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interfaces now used by batman advanced, e.g.::
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$ ip addr flush dev eth0
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Logging/Debugging
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=================
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All error messages, warnings and information messages are sent to the kernel
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log. Depending on your operating system distribution this can be read in one of
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a number of ways. Try using the commands: ``dmesg``, ``logread``, or looking in
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the files ``/var/log/kern.log`` or ``/var/log/syslog``. All batman-adv messages
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are prefixed with "batman-adv:" So to see just these messages try::
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$ dmesg | grep batman-adv
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When investigating problems with your mesh network, it is sometimes necessary to
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see more detailed debug messages. This must be enabled when compiling the
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batman-adv module. When building batman-adv as part of the kernel, use "make
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menuconfig" and enable the option ``B.A.T.M.A.N. debugging``
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(``CONFIG_BATMAN_ADV_DEBUG=y``).
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Those additional debug messages can be accessed using the perf infrastructure::
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$ trace-cmd stream -e batadv:batadv_dbg
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The additional debug output is by default disabled. It can be enabled during
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run time::
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$ batctl -m bat0 loglevel routes tt
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will enable debug messages for when routes and translation table entries change.
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Counters for different types of packets entering and leaving the batman-adv
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module are available through ethtool::
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$ ethtool --statistics bat0
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batctl
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======
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As batman advanced operates on layer 2, all hosts participating in the virtual
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switch are completely transparent for all protocols above layer 2. Therefore
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the common diagnosis tools do not work as expected. To overcome these problems,
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batctl was created. At the moment the batctl contains ping, traceroute, tcpdump
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and interfaces to the kernel module settings.
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For more information, please see the manpage (``man batctl``).
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batctl is available on https://www.open-mesh.org/
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Contact
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=======
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Please send us comments, experiences, questions, anything :)
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IRC:
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#batadv on ircs://irc.hackint.org/
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Mailing-list:
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b.a.t.m.a.n@open-mesh.org (optional subscription at
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https://lists.open-mesh.org/mailman3/postorius/lists/b.a.t.m.a.n.lists.open-mesh.org/)
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You can also contact the Authors:
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* Marek Lindner <mareklindner@neomailbox.ch>
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* Simon Wunderlich <sw@simonwunderlich.de>
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