On Wed, 7 Aug 2013 22:56:03 +0200 Patrick McHardy <kaber@xxxxxxxxx> wrote: > On Wed, Aug 07, 2013 at 10:26:00PM +0200, Jesper Dangaard Brouer wrote: > > On Wed, 7 Aug 2013 19:42:49 +0200 Patrick McHardy <kaber@xxxxxxxxx> wrote: [...] > > Besides shouldn't nth->ack_seq be zero, in a SYN packet? This is the > > SYN "replayed" towards the server right? > > > > I also pointed to this in an earlier patch Martin showed me, but he > > reported that changing this resulted in bad behavior. So, I would > > request Martin to re-test this part. > > Right, it should be zero, but it doesn't matter since the ACK flag isn't > set. This is used to propagate the sequence number to the hook function > to initialize the sequence adjustment data. While in the target function, > we don't have any connection tracking state to store this in. We could > set it to zero after that, but it shouldn't matter. I think it deserves a comment in the code, that you are using ack_seq, to relay this information to the hook, as its not obvious. And I think we should set it to zero after that, else it will be visible on the wire, and wireshark complains (with a warning) when it sees pure SYN packets with a non-zero ACK number (Martin send me a dump some time ago, and I just checked). p.s. thanks for working on this module, which we discussed during the Netfilter Workshop 2013. -- Best regards, Jesper Dangaard Brouer MSc.CS, Sr. Network Kernel Developer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
