On 17.01, Herbert Xu wrote: > On Sat, Jan 17, 2015 at 09:51:46AM +0000, Patrick McHardy wrote: > > > > I agree, however at least in the case of nftables you can easily do the same thing by adding millions of rules. > > I think that's a problem in itself. If a single packet can kill > the CPU through millions of rules, then namespaces would be a joke. > There has to be a limit to the number of rules or the processing > has to be deferred into thread context (thus subject to scheduler > control) at some point. I think that's a problem that's unrelated to netfilter. Its quite easy to configure something that will make the network stack eat up all the CPU, consider f.i.: bridge name bridge id STP enabled interfaces br0 8000.625dda62a3d4 no veth0 veth1 Now thing of bridging, veth, TC actions, iptables, routing, all in combination. Sure, single cases can be caught it might be possible to restrict them, but I don't believe that in the near term we will be able to handle this properly. And even if all loops etc are handled, what keeps the user from creating a million veth devices and putting them into a long chain? This needs to be fixed on a different level in my opinion. > > It doesn't make things worse. > > So I don't think that's a valid justification for ignoring this > hash table problem. -- 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
