batman-adv.rst (5703B)
1.. SPDX-License-Identifier: GPL-2.0 2 3========== 4batman-adv 5========== 6 7Batman advanced is a new approach to wireless networking which does no longer 8operate on the IP basis. Unlike the batman daemon, which exchanges information 9using UDP packets and sets routing tables, batman-advanced operates on ISO/OSI 10Layer 2 only and uses and routes (or better: bridges) Ethernet Frames. It 11emulates a virtual network switch of all nodes participating. Therefore all 12nodes appear to be link local, thus all higher operating protocols won't be 13affected by any changes within the network. You can run almost any protocol 14above batman advanced, prominent examples are: IPv4, IPv6, DHCP, IPX. 15 16Batman advanced was implemented as a Linux kernel driver to reduce the overhead 17to a minimum. It does not depend on any (other) network driver, and can be used 18on wifi as well as ethernet lan, vpn, etc ... (anything with ethernet-style 19layer 2). 20 21 22Configuration 23============= 24 25Load the batman-adv module into your kernel:: 26 27 $ insmod batman-adv.ko 28 29The module is now waiting for activation. You must add some interfaces on which 30batman-adv can operate. The batman-adv soft-interface can be created using the 31iproute2 tool ``ip``:: 32 33 $ ip link add name bat0 type batadv 34 35To activate a given interface simply attach it to the ``bat0`` interface:: 36 37 $ ip link set dev eth0 master bat0 38 39Repeat this step for all interfaces you wish to add. Now batman-adv starts 40using/broadcasting on this/these interface(s). 41 42To deactivate an interface you have to detach it from the "bat0" interface:: 43 44 $ ip link set dev eth0 nomaster 45 46The same can also be done using the batctl interface subcommand:: 47 48 batctl -m bat0 interface create 49 batctl -m bat0 interface add -M eth0 50 51To detach eth0 and destroy bat0:: 52 53 batctl -m bat0 interface del -M eth0 54 batctl -m bat0 interface destroy 55 56There are additional settings for each batadv mesh interface, vlan and hardif 57which can be modified using batctl. Detailed information about this can be found 58in its manual. 59 60For instance, you can check the current originator interval (value 61in milliseconds which determines how often batman-adv sends its broadcast 62packets):: 63 64 $ batctl -M bat0 orig_interval 65 1000 66 67and also change its value:: 68 69 $ batctl -M bat0 orig_interval 3000 70 71In very mobile scenarios, you might want to adjust the originator interval to a 72lower value. This will make the mesh more responsive to topology changes, but 73will also increase the overhead. 74 75Information about the current state can be accessed via the batadv generic 76netlink family. batctl provides a human readable version via its debug tables 77subcommands. 78 79 80Usage 81===== 82 83To make use of your newly created mesh, batman advanced provides a new 84interface "bat0" which you should use from this point on. All interfaces added 85to batman advanced are not relevant any longer because batman handles them for 86you. Basically, one "hands over" the data by using the batman interface and 87batman will make sure it reaches its destination. 88 89The "bat0" interface can be used like any other regular interface. It needs an 90IP address which can be either statically configured or dynamically (by using 91DHCP or similar services):: 92 93 NodeA: ip link set up dev bat0 94 NodeA: ip addr add 192.168.0.1/24 dev bat0 95 96 NodeB: ip link set up dev bat0 97 NodeB: ip addr add 192.168.0.2/24 dev bat0 98 NodeB: ping 192.168.0.1 99 100Note: In order to avoid problems remove all IP addresses previously assigned to 101interfaces now used by batman advanced, e.g.:: 102 103 $ ip addr flush dev eth0 104 105 106Logging/Debugging 107================= 108 109All error messages, warnings and information messages are sent to the kernel 110log. Depending on your operating system distribution this can be read in one of 111a number of ways. Try using the commands: ``dmesg``, ``logread``, or looking in 112the files ``/var/log/kern.log`` or ``/var/log/syslog``. All batman-adv messages 113are prefixed with "batman-adv:" So to see just these messages try:: 114 115 $ dmesg | grep batman-adv 116 117When investigating problems with your mesh network, it is sometimes necessary to 118see more detailed debug messages. This must be enabled when compiling the 119batman-adv module. When building batman-adv as part of the kernel, use "make 120menuconfig" and enable the option ``B.A.T.M.A.N. debugging`` 121(``CONFIG_BATMAN_ADV_DEBUG=y``). 122 123Those additional debug messages can be accessed using the perf infrastructure:: 124 125 $ trace-cmd stream -e batadv:batadv_dbg 126 127The additional debug output is by default disabled. It can be enabled during 128run time:: 129 130 $ batctl -m bat0 loglevel routes tt 131 132will enable debug messages for when routes and translation table entries change. 133 134Counters for different types of packets entering and leaving the batman-adv 135module are available through ethtool:: 136 137 $ ethtool --statistics bat0 138 139 140batctl 141====== 142 143As batman advanced operates on layer 2, all hosts participating in the virtual 144switch are completely transparent for all protocols above layer 2. Therefore 145the common diagnosis tools do not work as expected. To overcome these problems, 146batctl was created. At the moment the batctl contains ping, traceroute, tcpdump 147and interfaces to the kernel module settings. 148 149For more information, please see the manpage (``man batctl``). 150 151batctl is available on https://www.open-mesh.org/ 152 153 154Contact 155======= 156 157Please send us comments, experiences, questions, anything :) 158 159IRC: 160 #batadv on ircs://irc.hackint.org/ 161Mailing-list: 162 b.a.t.m.a.n@open-mesh.org (optional subscription at 163 https://lists.open-mesh.org/mailman3/postorius/lists/b.a.t.m.a.n.lists.open-mesh.org/) 164 165You can also contact the Authors: 166 167* Marek Lindner <mareklindner@neomailbox.ch> 168* Simon Wunderlich <sw@simonwunderlich.de>