B.A.T.M.A.N.
Daemon HowTo
Wesley Tsai
January 25, 2009
Abstract
B.A.T.M.A.N stands for “better approach to mobile ad-hoc networking”,
this is a new routing protocol for multi-hop ad-hoc mesh networks. Go to
http://www.open-mesh.net to see more information.
The following document will explain how to install and use the B.A.T.M.A.N.
daemon.
1 Installing from source
1.1 Pre-requirements
• Compile environment and libraries.
1. gcc
2. libc6-dev
3. build-essential
4. binutils
5. makedev
6. GNU make
7. libpthread
• Download the B.A.T.M.A.N. daemon code from the website
http://www.open-mesh.net/wiki/Download
1.2 Compiling
All you have to do is untar and make, then you will see the executable file called
batmand.
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2 Usage
$ wget \
http://downloads.open-mesh.net/batman/stable/sources/batman/batman-0.3.tar.gz
$ tar xzvf batman-0.3.tar.gz
$ cd batman-0.3
$ make
If you want reduce the size of executable file, just strip it by executing:
$ strip batmand
Note that if you want to help us finding a bug in the daemon, please don’t strip it.
1.3 Installing
Copy batmand to a location somewhere in your path, for example
$ cp batmand /usr/sbin/
Or start it right from the directory where you compiled it
$ ./batmand
2 Usage
If you execute batmand -h or -H, you will see the help page, in the following we will
explain all parameters and how to work with them in a mesh network.
2.1 SYNOPSIS
batmand [options] interface [interface...]
2.2 DESCRIPTION
You can start batmand without specifying options, but you have to choose at least
one interface batmand runs on.
$ batmand eth1
If you have more interfaces, then you just add them behind the first.
$ batmand eth1 eth2 eth3
The B.A.T.M.A.N. daemon can also run on alias interfaces. Note that we use alias
interfaces to separate B.A.T.M.A.N. routing protocol and olsr routing protocol.
$ batmand eth1:test1 eth2:test2 eth3:test3
Note that the B.A.T.M.A.N. daemon will take the ip address and the broadcast
address from the given interfaces.
Note also that you have to check whether your essid, channel or wifi mode is correct
or not.
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2.2 DESCRIPTION
2.2.1 -a add announced network(s)
The daemon announces the availability of a connection to another network. This
option can be used multiple times and can be used to add networks dynamically while
the daemon is running. The parameter has to be in the form of ip-address/netmask.
For example, if you are the node A, and you can connect to other network, then
you can execute -a to announce the gateway.
B.A.T.M.A.N. network other network
B 192.168.1.101
A
Figure 1: Announce A as gateway to B
If the other nodes in the B.A.T.M.A.N. network want to connect to node B after
receiving the announce network information form node A, then they will know they
can use node A as gateway to reach node B. Now, you know what a announced
network is, but executing this command is wrong:
$ batmand -a 192.168.100.101 eth1
Because you have to specify the netmask parameter and different netmask param-
eters cause different results. Let’s make a example:
$ batmand -a 192.168.100.101/32 eth1
In this case, it means that node A can only connect to node B, because your parameter
is /32.
$ batmand -a 192.168.100.101/24 eth1
In this case, it means that node A can connect to the whole 192.168.100.x network,
because your parameter is /24. So, if you use different netmask values, then the
results are different.
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2 Usage
B.A.T.M.A.N. network
B 192.168.100.101
C 192.168.200.201
Figure 2: Two announced networks
Node A can announce more than one network. To announce two networks execute
the following command:
$ batmand -a 192.168.100.101/24 -a 192.168.200.201/24 eth1
Note that node A has to have a route to connect the node or network.
2.2.2 -A delete announced network(s)
Delete networks to the daemons list of available connections to another network(s).
This option can be used multiple times and can only be used while the daemon is
running. The parameter has to be in the form of ip-address/netmask.
2.2.3 -b run connection in batch mode
The debug information are updated after a period of time by default, so if you use
“-b” it will execute once and then stop.
$ batmand eth1
$ batmand -b -c -d 1
In this case, it means run debug level 1 once.
Note that -b can only be used with -c and debug level 1 & 2.
2.2.4 -c connect via unix socket
The B.A.T.M.A.N. daemon offers a unix socket interface to which you can connect.
First, you have to create a B.A.T.M.A.N. daemon on your host, then use -c to connect
to its interface. Note you can create as many client sockets as you like. Deploy it
without any arguments to get the current configuration even if changed at runtime.
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2.2 DESCRIPTION
B.A.T.M.A.N.
Client 1
Client 2
Client 3
Figure 3: Multiple clients connected to B.A.T.M.A.N. interface
$ batmand eth1
$ batmand -c -d 1
In this case, you ask the daemon to output debug level 1 in your current shell. The
B.A.T.M.A.N. daemon will update the information after a period of time.
Note that if you use -c flag, then you only can use -d to see the debug level.
2.2.5 -d debug level
The debug level can be set to five values.
0 debug disabled (default)
1 list neighbors
2 list gateways
3 observe batmand
4 observe batmand (very verbose)
5 memory debug / cpu usage
Note that debug level 5 can be disabled at compile time.
For example, you can run in normal start:
$ batmand -d 1 eth1
5
2 Usage
Level 1 just lists the neighbors in your B.A.T.M.A.N. network.
Originator Router (#/128): Potential routers ... [B.A.T.M.A.N. 0.2, MainIF/IP:
eth2 105.131.131.175, UT: 0d 0h 3m]
105.131.83.2 105.131.1.3 ( 71): 105.131.1.3 ( 71)
105.131.1.2 105.131.1.2 ( 52): 105.131.1.2 ( 52)
105.131.56.10 105.131.1.4 ( 25): 105.131.1.4 ( 25),105.131.1.6 ( 15), 105.131.1.7 ( 10),..
105.131.131.70 105.131.131.70 (121): 105.131.131.70 (121)
• In the first line, we will see the version of the B.A.T.M.A.N. daemon, main
interface, main IP, and uptime.
• In the first column, we can see those IPs which we can reach.
• In the second column, we can see those IPs which we sent our packets to when
we want to reach the IP of the first column. The number in the parenthesis
indicates the link quality of the connection and the #/128 shows the maximum
number of packets.
• In the third column, we can see those IPs which are one hop neighbors and
rebroadcasted packets from the originator. The B.A.T.M.A.N. daemon will
choose the router with the best link quality from the potential router list.
In this case, 105.131.1.2 is a one hop neighbor of 105.131.131.175, because the
105.131.1.2 is originator, router and potential router at the same time. If 105.131.131.175
wants to exchange data with the 105.131.83.2, then it will sent its packets to the
105.131.1.3, because it is the router for this destination.
Level 2 just lists gateways in the B.A.T.M.A.N. network.
Gateway Router (#/128)
105.131.83.5 105.131.41.1 ( 57), gw class 11 −>6 MBit, reliability: 0
105.131.41.5 105.131.41.1 ( 53), gw class 11 −>6 MBit, reliability: 0
• In the first column, we can see those IPs which are our gateways.
• In the second column, we can see those IPs which we sent our packets to when
we want to reach the IP of the first column. The number in the parenthesis
indicates the link quality of the connection and the #/128 shows the maximum
number of packets. The gw_class means gateway class of the gateway and
11 ->6 MBit means how much bandwidth the gateway owner wants to share.
The reliability means how good the quality of the internet connection is. In
this case, 0 means this is the best quality. The reliability number will increase
if the quality is poor.
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2.2 DESCRIPTION
Level 3 has more information about the neighbors, or shows the error message
when you have an incorrect command. Note that if there is no neighbor in the
B.A.T.M.A.N. network, then it will display nothing.
Level 4 has so many information about the B.A.T.M.A.N. network, for example,
how many packets you sent, and sent to where, or how many packets you got, and
received from where etc.
2.2.6 -g gateway class
The gateway class is used to tell other nodes in the network your available internet
bandwidth. Just enter any number (optionally followed by “kbit” or “mbit”) and the
daemon will guess your appropriate gateway class. Use “/” to seperate the down-
and upload rates. You can omit the upload rate and batmand will assume an upload
of download
5
.
• 5000
• 5000kbit
• 5mbit
• 5mbit/1024
• 5mbit/1024kbit
• 5mbit/1mbit
You only can set the value in a normal start
$ batmand -g 5mbit/1024 -d 3 eth1
Note that if you use debug level 3, then you will know whether you succeed setting
the gateway class or not.
2.2.7 -o originator interval in ms
A node transmits broadcast messages (we call them originator message or OGM) to
inform the neighboring nodes about it’s existence. Originator interval is the time to
wait after sending one message and before sending the next message. The default
value is 1000 ms (1 second). In a mobile network, you may want to detect network
changes very quickly, so you need to send message very often, for example, use a
value of 500 ms. In a static network, you can save bandwidth by using a higher
value. This option is only available in daemon mode.
$ batmand -o 2000 eth1
In this case, batmand will wait 2 second until sending the next OGMs.
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2 Usage
2.2.8 -p preferred gateway
Set the internet gateway by yourself.
Note that this automatically switches your B.A.T.M.A.N. daemon to “internet
search modus” with “-r 1” unless “-r” is given. If the preferred gateway is not found
the gateway selection will use the current routing class to choose a gateway.
$ batmand -r 3 -d 3 -p 192.168.1.1 eth1
In this case, you set 192.168.1.1 as your preferred gateway, so all of your internet
packets will be sent to the 192.168.1.1.
2.2.9 -r routing class
The routing class can be set to four values - it enables “internet search modus”.
The daemon will choose an internet gateway based on certain criteria (unless “-p” is
specified):
0 set no default route (default)
1 use fast connection
2 use stable connection
3 use fast-switch connection
XX use late-switch connection
Level 1 B.A.T.M.A.N tries to find the best available connection by watching the
uplinks throughput and the link quality.
Level 2 B.A.T.M.A.N compares the link quality of the internet node and chooses
the one with the best connection.
Level 3 B.A.T.M.A.N compares the link quality of the internet node and chooses
the one with the best connection but switches to another gateway as soon as a better
connection is found.
Level XX B.A.T.M.A.N compares the link quality of the internet node and chooses
the one with the best link quality but switches to another gateway as soon as this
gateway has a TQ value which is XX better than the currently selected gateway.
XX ist a number between 3 and 256
$ batmand -r 3 -d 3 eth1
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In this case, the B.A.T.M.A.N. daemon will choose the best statistic internet con-
nection for you. Note that if you use debug level 3, then you will know whether you
succeeded setting the routing class or not.
2.2.10 -s visualization server
Since no topology database is computed by the protocol an additional solution to
create topology graphs has been implemented, the vis server. B.A.T.M.A.N. daemons
may send their local view about their single-hop neighbors to the vis server. It collects
the information and provides data in a format similar to OLSR’s topology information
output. Therefore existing solutions to draw topology graphs developed for OLSR
can be used to visualize mesh-clouds using B.A.T.M.A.N.
2.2.11 --policy-routing-script
This option disables the policy routing feature of batmand - all routing changes are
send to the script which can make use of this information or not. Firmware and
package maintainers can use this option to tightly integrate batmand into their own
routing policies. This option is only available in daemon mode.
3 Reference Links
• http://www.open-mesh.net/
• http://www.olsr.org/
4 Troubleshooting
4.1 Why the B.A.T.M.A.N. daemon doesn’t reload the setting after I fixed
the main IP?
You have to restart the B.A.T.M.A.N. daemon after you modified any network con-
figuration, otherwise the B.A.T.M.A.N. daemon won’t use the new settings.
$ killall batmand
$ batmand eth1
4.2 Why I can’t connect to the Internet after setting the default gateway?
You have to use NAT on your gateway or firewall if you use the -r or -p options to
set default route.
$ iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
Note that you don’t set the default route by yourself.
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4 Troubleshooting
Copyright
This work is licensed under the Creative Commons Attribution-Noncommercial-Share
Alike 3.0 License. To view a copy of this license, visit http://creativecommons.
org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 559 Nathan
Abbott Way, Stanford, California 94305, USA.
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