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diff --git a/Documentation/networking/batman-adv.txt b/Documentation/networking/batman-adv.txt new file mode 100644 index 00000000..88d4afbd --- /dev/null +++ b/Documentation/networking/batman-adv.txt @@ -0,0 +1,241 @@ +[state: 17-04-2011] + +BATMAN-ADV +---------- + +Batman advanced is a new approach to wireless networking which +does no longer operate on the IP basis. Unlike the batman daemon, +which exchanges information using UDP packets and sets routing +tables, batman-advanced operates on ISO/OSI Layer 2 only and uses +and routes (or better: bridges) Ethernet Frames. It emulates a +virtual network switch of all nodes participating. Therefore all +nodes appear to be link local, thus all higher operating proto- +cols won't be affected by any changes within the network. You can +run almost any protocol above batman advanced, prominent examples +are: IPv4, IPv6, DHCP, IPX. + +Batman advanced was implemented as a Linux kernel driver to re- +duce the overhead to a minimum. It does not depend on any (other) +network driver, and can be used on wifi as well as ethernet lan, +vpn, etc ... (anything with ethernet-style layer 2). + + +CONFIGURATION +------------- + +Load the batman-adv module into your kernel: + +# insmod batman-adv.ko + +The module is now waiting for activation. You must add some in- +terfaces on which batman can operate. After loading the module +batman advanced will scan your systems interfaces to search for +compatible interfaces. Once found, it will create subfolders in +the /sys directories of each supported interface, e.g. + +# ls /sys/class/net/eth0/batman_adv/ +# iface_status mesh_iface + +If an interface does not have the "batman_adv" subfolder it prob- +ably is not supported. Not supported interfaces are: loopback, +non-ethernet and batman's own interfaces. + +Note: After the module was loaded it will continuously watch for +new interfaces to verify the compatibility. There is no need to +reload the module if you plug your USB wifi adapter into your ma- +chine after batman advanced was initially loaded. + +To activate a given interface simply write "bat0" into its +"mesh_iface" file inside the batman_adv subfolder: + +# echo bat0 > /sys/class/net/eth0/batman_adv/mesh_iface + +Repeat this step for all interfaces you wish to add. Now batman +starts using/broadcasting on this/these interface(s). + +By reading the "iface_status" file you can check its status: + +# cat /sys/class/net/eth0/batman_adv/iface_status +# active + +To deactivate an interface you have to write "none" into its +"mesh_iface" file: + +# echo none > /sys/class/net/eth0/batman_adv/mesh_iface + + +All mesh wide settings can be found in batman's own interface +folder: + +# ls /sys/class/net/bat0/mesh/ +# aggregated_ogms gw_bandwidth hop_penalty +# bonding gw_mode orig_interval +# fragmentation gw_sel_class vis_mode + + +There is a special folder for debugging information: + +# ls /sys/kernel/debug/batman_adv/bat0/ +# gateways socket transtable_global vis_data +# originators softif_neigh transtable_local + + +Some of the files contain all sort of status information regard- +ing the mesh network. For example, you can view the table of +originators (mesh participants) with: + +# cat /sys/kernel/debug/batman_adv/bat0/originators + +Other files allow to change batman's behaviour to better fit your +requirements. For instance, you can check the current originator +interval (value in milliseconds which determines how often batman +sends its broadcast packets): + +# cat /sys/class/net/bat0/mesh/orig_interval +# 1000 + +and also change its value: + +# echo 3000 > /sys/class/net/bat0/mesh/orig_interval + +In very mobile scenarios, you might want to adjust the originator +interval to a lower value. This will make the mesh more respon- +sive to topology changes, but will also increase the overhead. + + +USAGE +----- + +To make use of your newly created mesh, batman advanced provides +a new interface "bat0" which you should use from this point on. +All interfaces added to batman advanced are not relevant any +longer because batman handles them for you. Basically, one "hands +over" the data by using the batman interface and batman will make +sure it reaches its destination. + +The "bat0" interface can be used like any other regular inter- +face. It needs an IP address which can be either statically con- +figured or dynamically (by using DHCP or similar services): + +# NodeA: ifconfig bat0 192.168.0.1 +# NodeB: ifconfig bat0 192.168.0.2 +# NodeB: ping 192.168.0.1 + +Note: In order to avoid problems remove all IP addresses previ- +ously assigned to interfaces now used by batman advanced, e.g. + +# ifconfig eth0 0.0.0.0 + + +VISUALIZATION +------------- + +If you want topology visualization, at least one mesh node must +be configured as VIS-server: + +# echo "server" > /sys/class/net/bat0/mesh/vis_mode + +Each node is either configured as "server" or as "client" (de- +fault: "client"). Clients send their topology data to the server +next to them, and server synchronize with other servers. If there +is no server configured (default) within the mesh, no topology +information will be transmitted. With these "synchronizing +servers", there can be 1 or more vis servers sharing the same (or +at least very similar) data. + +When configured as server, you can get a topology snapshot of +your mesh: + +# cat /sys/kernel/debug/batman_adv/bat0/vis_data + +This raw output is intended to be easily parsable and convertable +with other tools. Have a look at the batctl README if you want a +vis output in dot or json format for instance and how those out- +puts could then be visualised in an image. + +The raw format consists of comma separated values per entry where +each entry is giving information about a certain source inter- +face. Each entry can/has to have the following values: +-> "mac" - mac address of an originator's source interface + (each line begins with it) +-> "TQ mac value" - src mac's link quality towards mac address + of a neighbor originator's interface which + is being used for routing +-> "TT mac" - TT announced by source mac +-> "PRIMARY" - this is a primary interface +-> "SEC mac" - secondary mac address of source + (requires preceding PRIMARY) + +The TQ value has a range from 4 to 255 with 255 being the best. +The TT entries are showing which hosts are connected to the mesh +via bat0 or being bridged into the mesh network. The PRIMARY/SEC +values are only applied on primary interfaces + + +LOGGING/DEBUGGING +----------------- + +All error messages, warnings and information messages are sent to +the kernel log. Depending on your operating system distribution +this can be read in one of a number of ways. Try using the com- +mands: dmesg, logread, or looking in the files /var/log/kern.log +or /var/log/syslog. All batman-adv messages are prefixed with +"batman-adv:" So to see just these messages try + +# dmesg | grep batman-adv + +When investigating problems with your mesh network it is some- +times necessary to see more detail debug messages. This must be +enabled when compiling the batman-adv module. When building bat- +man-adv as part of kernel, use "make menuconfig" and enable the +option "B.A.T.M.A.N. debugging". + +Those additional debug messages can be accessed using a special +file in debugfs + +# cat /sys/kernel/debug/batman_adv/bat0/log + +The additional debug output is by default disabled. It can be en- +abled during run time. Following log_levels are defined: + +0 - All debug output disabled +1 - Enable messages related to routing / flooding / broadcasting +2 - Enable route or tt entry added / changed / deleted +3 - Enable all messages + +The debug output can be changed at runtime using the file +/sys/class/net/bat0/mesh/log_level. e.g. + +# echo 2 > /sys/class/net/bat0/mesh/log_level + +will enable debug messages for when routes or TTs change. + + +BATCTL +------ + +As batman advanced operates on layer 2 all hosts participating in +the virtual switch are completely transparent for all protocols +above layer 2. Therefore the common diagnosis tools do not work +as expected. To overcome these problems batctl was created. At +the moment the batctl contains ping, traceroute, tcpdump and +interfaces to the kernel module settings. + +For more information, please see the manpage (man batctl). + +batctl is available on http://www.open-mesh.org/ + + +CONTACT +------- + +Please send us comments, experiences, questions, anything :) + +IRC: #batman on irc.freenode.org +Mailing-list: b.a.t.m.a.n@open-mesh.org (optional subscription + at https://lists.open-mesh.org/mm/listinfo/b.a.t.m.a.n) + +You can also contact the Authors: + +Marek Lindner <lindner_marek@yahoo.de> +Simon Wunderlich <siwu@hrz.tu-chemnitz.de> |