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1 ==========
2 batman-adv
3 ==========
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
14 Batman advanced was implemented as a Linux kernel driver to reduce the overhead
15 to a minimum. It does not depend on any (other) network driver, and can be used
16 on wifi as well as ethernet lan, vpn, etc ... (anything with ethernet-style
17 layer 2).
18
19
20 Configuration
21 =============
22
23 Load the batman-adv module into your kernel::
24
25 $ insmod batman-adv.ko
26
27 The module is now waiting for activation. You must add some interfaces on which
28 batman can operate. After loading the module batman advanced will scan your
29 systems interfaces to search for compatible interfaces. Once found, it will
30 create subfolders in the ``/sys`` directories of each supported interface,
31 e.g.::
32
33 $ ls /sys/class/net/eth0/batman_adv/
34 elp_interval iface_status mesh_iface throughput_override
35
36 If an interface does not have the ``batman_adv`` subfolder, it probably is not
37 supported. Not supported interfaces are: loopback, non-ethernet and batman's
38 own interfaces.
39
40 Note: After the module was loaded it will continuously watch for new
41 interfaces to verify the compatibility. There is no need to reload the module
42 if you plug your USB wifi adapter into your machine after batman advanced was
43 initially loaded.
44
45 The batman-adv soft-interface can be created using the iproute2 tool ``ip``::
46
47 $ ip link add name bat0 type batadv
48
49 To activate a given interface simply attach it to the ``bat0`` interface::
50
51 $ ip link set dev eth0 master bat0
52
53 Repeat this step for all interfaces you wish to add. Now batman starts
54 using/broadcasting on this/these interface(s).
55
56 By reading the "iface_status" file you can check its status::
57
58 $ cat /sys/class/net/eth0/batman_adv/iface_status
59 active
60
61 To deactivate an interface you have to detach it from the "bat0" interface::
62
63 $ ip link set dev eth0 nomaster
64
65
66 All mesh wide settings can be found in batman's own interface folder::
67
68 $ ls /sys/class/net/bat0/mesh/
69 aggregated_ogms fragmentation isolation_mark routing_algo
70 ap_isolation gw_bandwidth log_level vlan0
71 bonding gw_mode multicast_mode
72 bridge_loop_avoidance gw_sel_class network_coding
73 distributed_arp_table hop_penalty orig_interval
74
75 There is a special folder for debugging information::
76
77 $ ls /sys/kernel/debug/batman_adv/bat0/
78 bla_backbone_table log neighbors transtable_local
79 bla_claim_table mcast_flags originators
80 dat_cache nc socket
81 gateways nc_nodes transtable_global
82
83 Some of the files contain all sort of status information regarding the mesh
84 network. For example, you can view the table of originators (mesh
85 participants) with::
86
87 $ cat /sys/kernel/debug/batman_adv/bat0/originators
88
89 Other files allow to change batman's behaviour to better fit your requirements.
90 For instance, you can check the current originator interval (value in
91 milliseconds which determines how often batman sends its broadcast packets)::
92
93 $ cat /sys/class/net/bat0/mesh/orig_interval
94 1000
95
96 and also change its value::
97
98 $ echo 3000 > /sys/class/net/bat0/mesh/orig_interval
99
100 In very mobile scenarios, you might want to adjust the originator interval to a
101 lower value. This will make the mesh more responsive to topology changes, but
102 will also increase the overhead.
103
104
105 Usage
106 =====
107
108 To make use of your newly created mesh, batman advanced provides a new
109 interface "bat0" which you should use from this point on. All interfaces added
110 to batman advanced are not relevant any longer because batman handles them for
111 you. Basically, one "hands over" the data by using the batman interface and
112 batman will make sure it reaches its destination.
113
114 The "bat0" interface can be used like any other regular interface. It needs an
115 IP address which can be either statically configured or dynamically (by using
116 DHCP or similar services)::
117
118 NodeA: ip link set up dev bat0
119 NodeA: ip addr add 192.168.0.1/24 dev bat0
120
121 NodeB: ip link set up dev bat0
122 NodeB: ip addr add 192.168.0.2/24 dev bat0
123 NodeB: ping 192.168.0.1
124
125 Note: In order to avoid problems remove all IP addresses previously assigned to
126 interfaces now used by batman advanced, e.g.::
127
128 $ ip addr flush dev eth0
129
130
131 Logging/Debugging
132 =================
133
134 All error messages, warnings and information messages are sent to the kernel
135 log. Depending on your operating system distribution this can be read in one of
136 a number of ways. Try using the commands: ``dmesg``, ``logread``, or looking in
137 the files ``/var/log/kern.log`` or ``/var/log/syslog``. All batman-adv messages
138 are prefixed with "batman-adv:" So to see just these messages try::
139
140 $ dmesg | grep batman-adv
141
142 When investigating problems with your mesh network, it is sometimes necessary to
143 see more detail debug messages. This must be enabled when compiling the
144 batman-adv module. When building batman-adv as part of kernel, use "make
145 menuconfig" and enable the option ``B.A.T.M.A.N. debugging``
146 (``CONFIG_BATMAN_ADV_DEBUG=y``).
147
148 Those additional debug messages can be accessed using a special file in
149 debugfs::
150
151 $ cat /sys/kernel/debug/batman_adv/bat0/log
152
153 The additional debug output is by default disabled. It can be enabled during
154 run time. Following log_levels are defined:
155
156 .. flat-table::
157
158 * - 0
159 - All debug output disabled
160 * - 1
161 - Enable messages related to routing / flooding / broadcasting
162 * - 2
163 - Enable messages related to route added / changed / deleted
164 * - 4
165 - Enable messages related to translation table operations
166 * - 8
167 - Enable messages related to bridge loop avoidance
168 * - 16
169 - Enable messages related to DAT, ARP snooping and parsing
170 * - 32
171 - Enable messages related to network coding
172 * - 64
173 - Enable messages related to multicast
174 * - 128
175 - Enable messages related to throughput meter
176 * - 255
177 - Enable all messages
178
179 The debug output can be changed at runtime using the file
180 ``/sys/class/net/bat0/mesh/log_level``. e.g.::
181
182 $ echo 6 > /sys/class/net/bat0/mesh/log_level
183
184 will enable debug messages for when routes change.
185
186 Counters for different types of packets entering and leaving the batman-adv
187 module are available through ethtool::
188
189 $ ethtool --statistics bat0
190
191
192 batctl
193 ======
194
195 As batman advanced operates on layer 2, all hosts participating in the virtual
196 switch are completely transparent for all protocols above layer 2. Therefore
197 the common diagnosis tools do not work as expected. To overcome these problems,
198 batctl was created. At the moment the batctl contains ping, traceroute, tcpdump
199 and interfaces to the kernel module settings.
200
201 For more information, please see the manpage (``man batctl``).
202
203 batctl is available on https://www.open-mesh.org/
204
205
206 Contact
207 =======
208
209 Please send us comments, experiences, questions, anything :)
210
211 IRC:
212 #batman on irc.freenode.org
213 Mailing-list:
214 b.a.t.m.a.n@open-mesh.org (optional subscription at
215 https://lists.open-mesh.org/mm/listinfo/b.a.t.m.a.n)
216
217 You can also contact the Authors:
218
219 * Marek Lindner <mareklindner@neomailbox.ch>
220 * Simon Wunderlich <sw@simonwunderlich.de>