Transfer files between Host OS and Mininet VM

It is possible to transfer files between mininet VM and the host OS. The protocol that is used for doing this is called SCP(Secure Copy Protocol).It is based on Secure Shell Protocol(SSH). It is a means of securely transferring computer files between a local host and and a remote host or between two remote hosts.

Follow the steps below to achieve this.


Step 1: Make sure that the mininet VM has a host-only network adapter configured.

In virtualbox network setting make sure that you have a NAT interface enabled that allows you to connect to internet. It will have an ip address like this : 192.168.56.103 ie a class C address.

Step 2: Install WinSCP

Download WinSCP from this link (Download WinSCP) and install the program.

A window like below will appear after installation.

3. Enter the credentials and connect

File Protocol: SCP

Host Name : 192.168.56.103 (or the ip in your host only adapter interface)

User name : mininet

Password : mininet

Click on Login. A window like below will appear.

Connecting Mininet Hosts to Internet

While working on my project on open vswitch I had to connect mininet hosts to internet to enable some functionalities in mininet hosts. After working on it for two days, I came to realise that its just 4 easy steps. If you are struggling with the same here is the solution.

Step 1: Make sure that your guest OS ie mininet OS is connected to the internet.

In virtualbox network setting make sure that you have a NAT interface enabled that allows you to connect to internet. It will have an ip address like this : 10.0.3.15 ie a class A address
Test by pinging www.google.com to make sure you are connected to internet from the guest OS ie Mininet OS.

Step 2: Start the network

Start a mininet netowrk with a switch and a host or any topology you prefer.

sudo mn  --switch ovsk --mac --topo single,2

The above command creates a network with single switch and two hosts.
This will create a switch s1 and two hosts h1 and h2.

Step 3: Connect the guest interface(that connects to the internet) to the ovs bridge

The command used to achieve this is an ovs-vsctl command which is used for quering and configuring openvswitchd(this is a process of openvswitch).

Open an xterm window for s1 as this command does not run directly on mininet.For this you need to ssh the guest OS from the host OS. If you don't know how to do this, you can refer to my earlier post titled "Error: Cannot Connect to Display"

Check the openvswitch configuration using the command: ovs-vsctl show
My switch had the following configuration.

root@mininet-vm:~# ovs-vsctl show
d27a9060-3edf-4ee7-a4cf-09e705c93f56
    Bridge "s1"
        Controller "ptcp:6634"
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "s1-eth1"
            Interface "s1-eth1"
        Port "s1-eth2"
            Interface "s1-eth2"
        Port "s1"
            Interface "s1"
                type: internal
    ovs_version: "2.0.1"

Now, run the following command to connect eth1 to s1: ovs-vsctl add-port s1 eth1

Check the configuration again using ovs-vsctl show. The new interface that is added has been highlighted in red.

root@mininet-vm:~# ovs-vsctl show
d27a9060-3edf-4ee7-a4cf-09e705c93f56
    Bridge "s1"
        Controller "ptcp:6634"
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "eth1"
            Interface "eth1"
        Port "s1-eth1"
            Interface "s1-eth1"
        Port "s1-eth2"
            Interface "s1-eth2"
        Port "s1"
            Interface "s1"
                type: internal
    ovs_version: "2.0.1"

Step 4: Run dhclient on hosts.

Open  xterm windows for h1 and h2 and run the following commands. The first command removes the ip from h1-eth0,the second command gets the ip address for h1-eth0 from dhcp server. The second command shows the interface description.

root@mininet-vm:~# ifconfig h1-eth0 0
root@mininet-vm:~# dhclient h1-eth0
root@mininet-vm:~# ifconfig
h1-eth0   Link encap:Ethernet  HWaddr 00:00:00:00:00:01
          inet addr:10.0.3.16  Bcast:10.0.3.255  Mask:255.255.255.0
          inet6 addr: fe80::200:ff:fe00:1/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:24 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3304 (3.3 KB)  TX bytes:1764 (1.7 KB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:1252 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1252 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:151432 (151.4 KB)  TX bytes:151432 (151.4 KB)

Now check the internet connectivity using ping.

root@mininet-vm:~# ping www.google.com
PING www.google.com (216.58.216.164) 56(84) bytes of data.
64 bytes from sea15s02-in-f4.1e100.net (216.58.216.164): icmp_seq=14 ttl=54 time=61.9 ms
64 bytes from sea15s02-in-f4.1e100.net (216.58.216.164): icmp_seq=15 ttl=54 time=60.7 ms
^C
--- www.google.com ping statistics ---
15 packets transmitted, 2 received, 86% packet loss, time 14065ms
rtt min/avg/max/mdev = 60.707/61.336/61.965/0.629 ms

Summary:

The command that we have used to achieve internet connectivity to hosts are:

ovs-vsctl add-port s1 eth1
ifconfig h1-eth0 0
dhclient h1-eth0

Error: Cannot Connect to display

In some virtual box images which does not have GUI support, the error mentioned in the title is encountered. This is because it does not support GUI and so it cannot display a graphical interface.

However, whether you are using Windows or Linux,there is a solution to this.

Step 1: Make sure you have host only networking adapter on your vm.

Make sure that you add an adapter with host only networking enabled on that adapter.
If you have host-only networking enabled, you will see an interface on your image with a class C ip address.
The IP Address is a class C address like 192.168.56.103.

To know this address use the commands ifconfig(if your image is linux based) or ipconfig(if your host is windows based.)

It will also have a class A address like 10.0.0.3 if you have NAT adapter enabled. This is used for connecting the virtualbox to the internet.

Step 2: Connecting to guest from host.

If you are accessing the guest using a command line, use the following command to access the guest and you do not need to follow step 3.

ssh -X username@address        ----------where -X enables X11 forwarding, username is the username  of the image and address is the host-only address of the guest.

If you are using a Windows host.

Make sure that you enable X11 forwarding in the ssh client(Eg, Putty, Secure Crt) you are using.

In Putty,Go to Connection > SSH > X11 > Check mark the X11 Forwarding option.
In Secure Crt, Go to Connection--> Port Forwarding--> Remote/X11 and check the Enforce X11 authentication checkbox

Step 3: Start Xming(If you are using Windows host)

Download Link : http://www.straightrunning.com/XmingNotes/

If you are using the Windows as a host you will need to start Xming first, which is a display server for Windows.

Now, to display the GUI for applications use the command xterm to open the GUI.
For eg.: In case of mininet use 'xterm s1' to display the xterm window for switch 1.