From: Herbert Xu <[EMAIL PROTECTED]> Date: Tue, 29 Nov 2005 18:34:41 +1100
> On Tue, Nov 29, 2005 at 08:02:34AM +0100, Patrick McHardy wrote: > > It seems in most places where only IPCB(skb)->opt is cleared > > the entire CB should be cleared. A couple of spots also look > > completely unnecessary, for example all places clearing the CB > > before passing the packet to netif_rx. I would expect the next > > user beeing responsible for clearing the space he needs if > > neccessary. > > Agreed. However, it seems that ip_rcv() only clears the CB options > if ihl is greater than 5. So until that's changed the people feeding > netif_rx will have to clear the CB. I wonder if that stuff can be simplified somehow. We only use those options in two ways: 1) To process early in input via ip_options_compile() and the source route check in ip_rcv_finish() 2) To do forwarding processing on options in ip_forward_finish() and the multicast equivalent in ipmr.c 3) For locally destined packets, when the options are to be passed to the user via a recvmsg() CMSG. Well, there is a 4th, which is what we're talking about here, which is all of the zero'ing out of the thing during encapsulation which is mostly a waste. I think #1 and #2 can be handled by an on-stack copy of "struct ip_options" high enough in the call chain, but #3 is a bit less trivial to cope with like that. It would be nice to kill the IPCB() copy, and give us 12 bytes back in skb->cb[] :-) - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
