batman-adv.rst 5.6 KB

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  1. .. SPDX-License-Identifier: GPL-2.0
  2. ==========
  3. batman-adv
  4. ==========
  5. Batman advanced is a new approach to wireless networking which does no longer
  6. operate on the IP basis. Unlike the batman daemon, which exchanges information
  7. using UDP packets and sets routing tables, batman-advanced operates on ISO/OSI
  8. Layer 2 only and uses and routes (or better: bridges) Ethernet Frames. It
  9. emulates a virtual network switch of all nodes participating. Therefore all
  10. nodes appear to be link local, thus all higher operating protocols won't be
  11. affected by any changes within the network. You can run almost any protocol
  12. above batman advanced, prominent examples are: IPv4, IPv6, DHCP, IPX.
  13. Batman advanced was implemented as a Linux kernel driver to reduce the overhead
  14. to a minimum. It does not depend on any (other) network driver, and can be used
  15. on wifi as well as ethernet lan, vpn, etc ... (anything with ethernet-style
  16. layer 2).
  17. Configuration
  18. =============
  19. Load the batman-adv module into your kernel::
  20. $ insmod batman-adv.ko
  21. The module is now waiting for activation. You must add some interfaces on which
  22. batman-adv can operate. The batman-adv soft-interface can be created using the
  23. iproute2 tool ``ip``::
  24. $ ip link add name bat0 type batadv
  25. To activate a given interface simply attach it to the ``bat0`` interface::
  26. $ ip link set dev eth0 master bat0
  27. Repeat this step for all interfaces you wish to add. Now batman-adv starts
  28. using/broadcasting on this/these interface(s).
  29. To deactivate an interface you have to detach it from the "bat0" interface::
  30. $ ip link set dev eth0 nomaster
  31. The same can also be done using the batctl interface subcommand::
  32. batctl -m bat0 interface create
  33. batctl -m bat0 interface add -M eth0
  34. To detach eth0 and destroy bat0::
  35. batctl -m bat0 interface del -M eth0
  36. batctl -m bat0 interface destroy
  37. There are additional settings for each batadv mesh interface, vlan and hardif
  38. which can be modified using batctl. Detailed information about this can be found
  39. in its manual.
  40. For instance, you can check the current originator interval (value
  41. in milliseconds which determines how often batman-adv sends its broadcast
  42. packets)::
  43. $ batctl -M bat0 orig_interval
  44. 1000
  45. and also change its value::
  46. $ batctl -M bat0 orig_interval 3000
  47. In very mobile scenarios, you might want to adjust the originator interval to a
  48. lower value. This will make the mesh more responsive to topology changes, but
  49. will also increase the overhead.
  50. Information about the current state can be accessed via the batadv generic
  51. netlink family. batctl provides a human readable version via its debug tables
  52. subcommands.
  53. Usage
  54. =====
  55. To make use of your newly created mesh, batman advanced provides a new
  56. interface "bat0" which you should use from this point on. All interfaces added
  57. to batman advanced are not relevant any longer because batman handles them for
  58. you. Basically, one "hands over" the data by using the batman interface and
  59. batman will make sure it reaches its destination.
  60. The "bat0" interface can be used like any other regular interface. It needs an
  61. IP address which can be either statically configured or dynamically (by using
  62. DHCP or similar services)::
  63. NodeA: ip link set up dev bat0
  64. NodeA: ip addr add 192.168.0.1/24 dev bat0
  65. NodeB: ip link set up dev bat0
  66. NodeB: ip addr add 192.168.0.2/24 dev bat0
  67. NodeB: ping 192.168.0.1
  68. Note: In order to avoid problems remove all IP addresses previously assigned to
  69. interfaces now used by batman advanced, e.g.::
  70. $ ip addr flush dev eth0
  71. Logging/Debugging
  72. =================
  73. All error messages, warnings and information messages are sent to the kernel
  74. log. Depending on your operating system distribution this can be read in one of
  75. a number of ways. Try using the commands: ``dmesg``, ``logread``, or looking in
  76. the files ``/var/log/kern.log`` or ``/var/log/syslog``. All batman-adv messages
  77. are prefixed with "batman-adv:" So to see just these messages try::
  78. $ dmesg | grep batman-adv
  79. When investigating problems with your mesh network, it is sometimes necessary to
  80. see more detailed debug messages. This must be enabled when compiling the
  81. batman-adv module. When building batman-adv as part of the kernel, use "make
  82. menuconfig" and enable the option ``B.A.T.M.A.N. debugging``
  83. (``CONFIG_BATMAN_ADV_DEBUG=y``).
  84. Those additional debug messages can be accessed using the perf infrastructure::
  85. $ trace-cmd stream -e batadv:batadv_dbg
  86. The additional debug output is by default disabled. It can be enabled during
  87. run time::
  88. $ batctl -m bat0 loglevel routes tt
  89. will enable debug messages for when routes and translation table entries change.
  90. Counters for different types of packets entering and leaving the batman-adv
  91. module are available through ethtool::
  92. $ ethtool --statistics bat0
  93. batctl
  94. ======
  95. As batman advanced operates on layer 2, all hosts participating in the virtual
  96. switch are completely transparent for all protocols above layer 2. Therefore
  97. the common diagnosis tools do not work as expected. To overcome these problems,
  98. batctl was created. At the moment the batctl contains ping, traceroute, tcpdump
  99. and interfaces to the kernel module settings.
  100. For more information, please see the manpage (``man batctl``).
  101. batctl is available on https://www.open-mesh.org/
  102. Contact
  103. =======
  104. Please send us comments, experiences, questions, anything :)
  105. IRC:
  106. #batman on irc.freenode.org
  107. Mailing-list:
  108. b.a.t.m.a.n@open-mesh.org (optional subscription at
  109. https://lists.open-mesh.org/mailman3/postorius/lists/b.a.t.m.a.n.lists.open-mesh.org/)
  110. You can also contact the Authors:
  111. * Marek Lindner <mareklindner@neomailbox.ch>
  112. * Simon Wunderlich <sw@simonwunderlich.de>