batman-adv

• Better Approach To Mobile Adhoc Network
• Implemented as a linux kernel module
• Operates on layer 2 of network stack

batman-adv

• All the packets are encapsulated and routed by batman-adv
• All the participating nodes appear to be link-local

batman-adv

• Supports anything on top of layer 2 : IPV4, IPV6, DHCP, IPX
• Nodes can participate in a mesh without having an IP
• Easy integration of non-mesh clients (think Android)

batctl

• A tool to configure and debug the batman-adv kernel module
• Interface to settings and status information of batman-adv
• Provides a layer-2 version of ping, traceroute and tcpdump(MAC)

Configuration

• Add and remove interfaces to the mesh network
• Set or change parameters of batman-adv module
• Enable or disable features of batman-adv

batctl

• Get the list of mesh nodes and non-mesh nodes in the network
• Log messages from batman-adv
• List of available gateways

Compatibility Check

Kernel Version

					uname -r # 3.19.0-25-generic
					

Find compatible versions

Dowload

Compile batman-adv

# compile
make -j4
# find module
ls *.ko
# insert module
sudo insmod batman-adv.ko
# check version
batctl -v
					

Compile batctl

# compile
make -j4
# install
sudo make install
# check version
batctl -v
					

Add Interface

Which interface to add to batman-adv to build the mesh network?

# Add an interface wlan0/eth0
batctl if add wlan0
# check interface
batctl if
						

bat0 : Virtual Interface

Simple Mesh Network

# kill network manager
sudo service network-manager stop
# load the module up
modprobe batman-adv
# setup network interfaces
ip link set up dev eth0
# set mtu compatible with batman
ip link set mtu 1532 dev wlan0
# configure the wlan interface to operate with mtus of 1532
#		(batman requires it) and turn enc off 
iwconfig wlan0 mode ad-hoc channel 6 essid PYMESH ap 02:12:34:56:78:9A enc off
# add wlan0 to the batman-adv virtual interface
# 	(so it can communicate with other batman-adv nodes)
batctl if add wlan0
# bringing up wireless ad-hoc interface
ifconfig wlan0 up
# bringing up bat0 interface
ifconfig bat0 192.168.1.4 up
						

How to kill BATMAN?

# disable kernel module
rmmod batman-adv
# restart network manager
service network-manager restart
					

Bridge

Need to bridge Adhoc and Infrastructure APs

To let non-mesh nodes (think Android) connect to the network

Setup Bridge Interface

ip link add name mesh-bridge type bridge
ip link set dev eth0 master mesh-bridge
ip link set dev bat0 master mesh-bridge
ip link set up dev eth0
ip link set up dev bat0
ip link set up dev mesh-bridge
					

Compatibility Check

Compiled Packages

Flashing your Router

LUCI Interface

IP Allocation. How?

Configuring DHCP

• Go to /etc/config/dhcp
• start : start address
• limit : number of devices to serve

/etc/config/dhcp

config dhcp 'lan'
      option interface 'lan'
      option start '100'
      option limit '100'
      option leasetime '12h'
		

/etc/config/network

config interface 'lan'
    option ipaddr '192.168.1.1'
    option netmask '255.255.255.0'
		

What is DNS?

• Domain Name Server
• Human readable names for services

How does it work?

How do we do it?

Dnsmasq Configuration

 192.168.1.162 pymesh.p2p

Dnsmasq Configuration

Dnsmasq Configuration

Use Cases

• Chat
• Voice Call
• Social Networking
• Micro-blogging
• File Sharing
• Personal Website : Portfolio
• Knowledge sharing

Serval Project

Serval Project

Batphone for Android

Rumble

Rumble

• Decentralized and delay-tolerant twitter-like mobile application
• Enables the spread of messages in an epidemic fashion using automatically formed and opportunistic local ad-hoc network
• Every message sent or received with are stored on the local database and pushed to every other device it meets
• Messages naturally propagates throughout the network using social links as the underlying infrastructure

Briar Project

Briar Project

• Peer-to-peer encrypted messaging and forums
• Messages are stored securely on your device, not in the cloud
• Connect directly with nearby contacts - no Internet access required
• Free and open source software
• Designed for activists, journalists, and anyone else who needs a safe, easy and robust way to communicate

Open Tracker

opentracker is a open and free bittorrent tracker project.

It aims for minimal resource usage and is intended to run at your wlan router.

Open Tracker

A torrent tracker basically is an http-Server that collects all clients ip addresses into pools sorted by one of the request strings parameters and answers all other clients that specified this exact same parameter a list of all other recent clients.

Kiwix

• An Offline web browser to browse wikipedia content
• Serves offline content from dump files called zim files

Zim Files

Download Kiwix

Download Kiwix from here.

Launch Kiwix

Run the executable file named kiwix.

Open Zim File

Choose Zim File

Browse Offline Content

Serve Local Content

Libre Digital Library

Motivation

In the current model of Internet, or any large network, both providing a service and connecting to a service are unnecessarily complicated.

To make a service visible, one needs to register a name as proxy to the service (IP + PORT).

To find a needed service, one needs support from a centralized DNS server.

This is where zeroconf comes in.

Pillars of Zero Conf

A set of technologies that automatically creates a usable computer network

Three Pillars of Zero Conf are

Service Discovery

• ZeroConf is a three-layered system with Service Discovery on top of naming and addressing
• Logical Services as primary entities on the network
• Discovery/Advertisement of services instead of hardware/software
• A new device connected to the network should learn the services available in the network rather than being manually configured by the user

Service Discovery

• Periodic (sensible) querying for services
• When a service is started it sends out multicast messages
• When a service stops its sends out multicast "good bye"
• Leases are given to services, if they are not renewed, the service name will not appear on the list of services on the client device

Address Selection

• Claiming an IP : ARP messages to know if the IP is already in use
• ARP Probe : An ARP request with Sender IP as all zeros is sent with a target address that is desired by the host
• Sender MAC address is put into the ARP req, to identify if the request is from the host itself or some other device desiring the same address

Announcement

• After claiming an IP address (by querying for desired IP using ARP requests), a host announces I am 10.4.2.45
• Announcing the claim is essential to flush the old MAC-IP mapping in the neighbours' ARP cache
• Announce the IP by sending Sender and Target addresses as same claimed address

Defending an IP

• When the host is offline for a while it needs to claim the address again, since some other device could have claimed the address while the host is offline
• Reply to ARP request from competitors looking to claim what is rightfully yours
• Back off and choose a different IP in time of conflict

Name Resolution

• Translate between names and IP addresses without a DNS server
• A multi-cast DNS (mDNS) server is a distributed DNS server that exists simply because all the machines on a local subnet run a special daemon
• Daemons running on either sides of a router can’t discover each other, so the .local domain is restricted to the local-link

How does it work?

• IP multicast query message that asks the host having that name to identify itself
• The target machine then multicasts a message that includes its IP address
• All machines in that subnet can then use that information to update their mDNS caches
• Devices can refer to the target computer by name, eg : ping my_name.local, ssh my_name.local, ftp my_name.local

Implementation

Apple's Bonjour

Bonjour is Apple's implementation of zero-configuration networking (zeroconf), a group of technologies that includes service discovery, address assignment, and hostname resolution. Bonjour locates devices such as printers, other computers, and the services that those devices offer on a local network using multicast Domain Name System (mDNS) service records.

Avahi

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. This enables you to plug your laptop or computer into a network and instantly be able to view other people who you can chat with, find printers to print to or find files being shared.