Yet Another Overlay Software Defined Network

Until Java bindings for libtuntap are implemented, YAOSDN uses clj-linux-net which is Linux only. Well, I'll consider creating JNI/JNA interface on my spare time, but don't know how much would it take.

Install prerequisites for Fedora / CentOS / RHEL:

sudo dnf update
sudo dnf install iproute git java-1.8.0-openjdk

Install prerequisites for Debian / Ubuntu:

sudo apt-get update
sudo apt-get install iproute2 git openjdk-8-jre

Install Leiningen.

Get YAOSDN sources:

git clone https://github.com/yaosdn/yaosdn.git
cd yaosdn

On the first console do the following to create tun2 interface with 10.0.2.2/24 ip address:

export TUN_IF=tun2
export TUN_IP=10.0.2.2/24

sudo ip tuntap add dev $TUN_IF mode tun user $USER
sudo ip addr add $TUN_IP dev $TUN_IF
sudo ip link set $TUN_IF up
sudo tcpdump -vnni $TUN_IF

One the second console do the same operation for tun3 interface with 10.0.3.3/24 ip address:

export TUN_IF=tun3
export TUN_IP=10.0.3.3/24

sudo ip tuntap add dev $TUN_IF mode tun user $USER
sudo ip addr add $TUN_IP dev $TUN_IF
sudo ip link set $TUN_IF up
sudo tcpdump -vnni $TUN_IF

So, now we've got two IPs in two separate networks. How do we send pings between them? Well, SD in YAOSDN means Software Defined and thus we may simply mangle IP addresses as we wish.

Let packets transmitted through tun2 to 10.0.2.0/24 network increase their third octet for source and destination fields so that pinging 10.0.2.3 would internally mean sending packets from 10.0.3.2 to 10.0.3.3. And vice versa for tun3 let's decrease packets' third octet number. So, answering to 10.0.3.2 would internally mean sending packet with source 10.0.2.3 and destination 10.0.2.2.

When mangling ICMP packets by simply changing source and destination, the checksum will actually broke. We will fix that rebuilding packets when sending them using automatic checksum correction - internally used pcap4j allows us to do that.

Open the third terminal and run YAOSDN REPL:

lein repl

Now start procedure that I've written for some simplification of doing the above:

(repl-test-local-node "tun2" inc)

Do the same for the fourth terminal:

lein repl

For tun3 we do mirrored operation - we decrease third octet in IP:

(repl-test-local-node "tun3" dec)

Here we just use ping command to check out if this actually works:

ping 10.0.2.3

You should see packets (source and destination IPs) in each opened console and successful pinging. If something is not working - don't hesitate to create an issue here so I may try to help you.

On each node create tun0 interface where 0 is a number of your choice by using snippets from the above. Assign any non-conflicting IP address (preferably from the private range) to freshly created tun0.

Start YAOSDN on each node:

lein run tun0

If nodes are in the same subnet and multicast packets are allowed then they should find each other automatically. Otherwise you should consider configuring Apache Ingite which is used as a broker internally.

Copyright © 2018 Sergey Sobko

Distributed under the MIT License.