testing a network driver with different buffer layouts

[Zoltan Kiss]

Hi,

I'm looking for a way to test our netback/netfront drivers with various 
buffer layouts, and I'm interested to see whether packetdrill can be 
used for that purpose.
These drivers are used in Xen based systems to facilitate network 
communication between guests and the control domain. Technically 
speaking, I want to inject skbs at one end (i.e. call the device's 
start_xmit with my skb), and see what turned up on the other end. The 
most important things I want to tinker with are the sizes of the linear 
buffer and the frags, frag_lists and so on.
Do you think there is a way to  make packetdrill to do that for me 
somehow? As far as I see it works on a much higher level, and lives in 
the userspace, so I guess it would be a bit hard to specify the exact 
buffer layouts from there.

Regards,

Zoltan Kiss

[Neal Cardwell]

Agreed. I don't think packetdrill would work well for your purposes.
It sounds like you want an in-kernel tool so that you can construct
arbitrary skbs.

Perhaps pktgen?
net/core/pktgen.c
and
https://www.kernel.org/doc/Documentation/networking/pktgen.txt

neal

[Zoltan Kiss]

Yes, thanks, with some modifications it could be used for my purposes!

Zoli