On Thu, Aug 08, 2013 at 10:04:48AM +0200, Jesper Dangaard Brouer wrote: > > 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. Agreed, I've added a comment. > 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). I'm a bit reluctant to do the entire "make skb writable, change packet, update checksum" dance for a cosmetic issue when wireshark should in fact ignore the value since the ACK flag is not set. I'll give it a try and see how ugly it gets. > p.s. thanks for working on this module, which we discussed during the > Netfilter Workshop 2013. Well, I think its pretty cool considering the numbers ;) -- 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
