Hi, I need to test the behavior of a kernel module when it is probed for data while some of its expected packets have arrived and some have not. Normally, this module expects to be polled when all packets are sure to have arrived. The network is a deterministic one (called EtherCAT). The solution that came to me was to put a bridge in between the network and introduce a delay between the packets being forwarded. This way, I can deterministically poll the kernel module in question when some of its packets have arrived while the rest not. If you are interested in knowing more, you can read these two questions that I asked elsewhere: http://serverfault.com/questions/360466/how-to-write-a-netfilter-kernel-module-and-use-it http://stackoverflow.com/questions/9313088/how-to-write-custom-module-for-ebtables Unfortunately, I could not find an answer to my problem anywhere, nor could anyone answer them. What I am trying to do is basically this: - Put a bridge in the middle of the network (successfully done using blctr) - Write a kernel module, checking all the packets that pass through the bridge. * In this phase, stall inside one of the functions to make sure there is a certain delay between packets being forward. - Make ebtables use my filter I took a code from linux-source/net/bridge/netfilter/ebt_ip.c, made the match and check functions simply return true (so they match all the packets) and use xt_register_match in init_module as was done in ebt_ip.c This is the registration data I am using: static struct xt_match reg __read_mostly = { .name = "any", // I tried "ip" also, but that didn't change anything .revision = 0, .family = NFPROTO_BRIDGE, .match = match, .checkentry = check, .matchsize = XT_ALIGN(4), // I have no idea what this is! I just gave it 4 as if its an int .me = THIS_MODULE }; By the way, I'm talking about Linux 2.6.32 Now I put some log inside match and check functions to make sure they are called, but they are not. I have no clue how to make it work and I can't find anything useful on the net. My question is, how can I make ebtables call my match and check functions before forwarding the messages? That is, how can I put my filter in effect? Thank you, Shahbaz -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
