Listening on Virtual Interface

Question

My objective is to create a to create a virtual wireless interface and to attach a listener on that interface. I am trying to do this using a C program.

So far I have been able to create the virtual interface by the following methods :

• Using the linux iw commands : `

sudo iw phy phy0 interface add mySta1 type station

but I was unable to find the library to do the same using C program.

• Using Tun/Tap persistent interfaces :

  http://backreference.org/2010/03/26/tuntap-interface-tutorial/

char tun_name[IFNAMSIZ];
strcpy(tun_name, "MyTun");
tunfd = tun_alloc(tun_name, IFF_TUN | IFF_NO_PI);

where tun_alloc is my function which uses ioctl to create the interface

ioctl(fd, TUNSETIFF, (void *) &ifr)

but there is no wireless extensions for this interface

For listening on the interface :

nread = read(tunfd,buffer,sizeof(buffer));

But this only works on tun devices which I create using my program or programs like openvpn. When used with any other interface like wlan0, ioctl gives the error 'Invalid argument'

Is my approach to the problem correct ? Is there any other way to achieve this ? I want to know the following :

1. Is there a way of attaching the tun device on devices created by 'iw add interface' commands ?
2. Is there a way of making a virtual wireless tun/tap interface or changing the type of an existing tun interface to wireless ?

Answer 1

If you want to achieve "iw phy..." in C program - just look at "iw" program sources. Probably it is achieved by some ioctls or netlink.

Answers to your questions:

1. Virtual TUN/TAP device means that this device is independent of any hardware. It it only software solution. You cannot easily in userspace attach TUN/TAP device to wireless interface.

2. No, as I wrote in answer 1. the TUN/TAP is only virtual device and it cannot be converted to wifi device type.

Answer 2

i don't know about any existing libraries for this. If your only intention is to get this working from your code, why don't you follow this.

system("iw phy phy0 interface add mySta1 type station");

Its obviously ugly, but it does its purpose.