How-to and virtualization issues

[Fustaccio]

Hello.
I need to modify some internal modules about networking issues in linux kernel, specifically I have to modify the maximum dimension of packets and other stuff. I have 2 questions:
1) Would you use a real machine for debugging or virtualization?In case of virtualization, what's the best choice for these issues among KVM, VirtualBox or something else? Does a VM give complete access to all HW devices and simulates real networking?

2) Is it possible to unload modules (e.g. ARP) and re-load a hacked version of it without having to compile all kernel again?

Thanks in advance.

[pcmattman]

Hi,

Does a VM give complete access to all HW devices and simulates real networking?

It does. VirtualBox for instance bridges the VM network adapter to a NIC on the host. QEMU's usermode network stack emulates a virtual network.

specifically I have to modify the maximum dimension of packets and other stuff.

What do you mean by this, exactly?

Cheers,
Matt

[Fustaccio]

Hi, thanks for answer.
I mean I have to introduce a MPLS solution for some reasons, i.e. putting space for a further header; it follows I have to reduce maximum dimension of expected data.

So I can develop my hacked kernel and test it on Virtual Box, letting two Virtual Boxes on two different machines comunicate? Can you help me on the other questions I asked?

Thanks again. Cheers

[pcmattman]

Hi,

So I can develop my hacked kernel and test it on Virtual Box, letting two Virtual Boxes on two different machines comunicate?

You can.

Can you help me on the other questions I asked?

I'm not well-versed on Linux and Linux modules in particular, so I would prefer not to provide incorrect information. I'm certain someone else will be able to answer the module question far better than I could.

Cheers,
Matt