Jan Engelhardt wrote: > while writing a netfilter match module I found that, when run, > skb->h.th is not set to the TCP header (it is assured that the packet > _is_ TCP), as this printk shows me: > > skb: h.th=cb5bc4dc nh.iph=cb5bc4dc mac.raw=cb5bc4ce head=cb5bc400 > data=cb5bc4dc tail=cb5bc510 end=cb5bc580 > > Is it intended that skb->h.th is not set to skb->data + length of ip > header (skb->data+protoff as far as netfilter matches are concerned)?
The netfilter hooks are placed in the network layer, therefore skb->h.th is not set in the input path since the packet did not reach the transport layer yet (prerouting/input), but it is set in the output path because it already passed by the transport layer (output/postrouting). BTW, I'm unsure that this can be of interest in the linux-kernel list, please there's no need to cc everyone. Use netfilter or linux-net instead next time. -- The dawn of the fourth age of Linux firewalling is coming; a time of great struggle and heroic deeds -- J.Kadlecsik got inspired by J.Morris - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
