hi, I'm not very sure about if I can ask questions about xen here. I have tow questions. The first one is that I'm looking for methods about inter-domain communication for xen. I know besides network, VMs on the same physical machine can exchange information by event channel and grant table. But are these two ways working in kernel mode as part of drivers, or can I directly use them just like network socket in user mode? I've tried to google it but only got something I can't fully understand. The second questions is I want to do some extra jobs (like check tcp/ip header and change some bits) to packages in the virtual network of xen. As all domUs' packages are passing the back driver of dom0, I want to put this extra action to network back driver of dom0. But I'm not sure which part of the source code has the function of receiving packages from front driver. I think it may be function xen_netbk_tx_action. I'll be very appreciated if someone knows the answer. Thanks! summerxyt