On Fri, 11 Feb 2005 01:07:55 +0100 (CET), Henrik Nordstrom wrote > On Thu, 10 Feb 2005, junk wrote: > > > i'm coding a virtual interface. That virtual interface has to receive packets > > coming on eth0. For that purpose, i'm using ipt_ROUTE. That works great, i can > > see my packets arriving on red0 (my virtual interface). > > > > The problem is that the destination MAC is the one of eth0, so, it seems the > > kernel doesn't really deliver the packet to my driver. I can see it in tcpdump > > but my driver receive function is never called. > > It is not due to the destination MAC, but to what ipt_ROUTE does. > > ipt_ROUTE reoutes the packet as if it came in on the other interface, > all done at the IP layer in the kernel, it does not resubmit the > packet to the driver level. > > The MAC is not modified as this is not relevant to the IP layer, and > there really isn't any reason why it should be modified either. The > MAC used in received skbufs is the MAC the sending station was > addressing the packet to, not the MAC of the receiving interface. > Usually they are the same, but not always. > > Can you give an more detailed example of what it is you are trying > to accomplish or why you need a custom virtual interface driver? It > is possible (or even likely) there is other better tools for the job. > > Also I am a little confused on your virtual interface driver. > Normally virtual interface drivers does not have a receive function, > only a transmit function called when packets are routed to be > transmitted on the interface.. How you make packets arrive at the > interface driver is up to you (emulated hardware or whatever). > > Regards > Henrik > > - > : send the line "unsubscribe linux-net" > in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo > info at http://vger.kernel.org/majordomo-info.html The purpose is to run a redundant network. My virtual interface has to duplicate packets it receive from software, and send each copy of it on eth0 and eth1 respectively. >From the application, there is only one interface: red0. red0 has to: - duplicate packets having red0 as outgoing interface (real output iface are eth0/eth1) - receive packets from eth0/eth1, discarding the copy (as eth0 and eth1 receive the same data), pass the packet to application - alert userland if eth0 or eth1 comes down The problem is that I want my driver to know about incoming packets, not only the software. - : send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
