Hi, On Wed, Feb 19, 2014 at 04:13:37PM +0100, Dennis Jacobfeuerborn wrote: > On 18.02.2014 12:25, Pablo Neira Ayuso wrote: > >Hi, > > > >I have registered a subdomain for nftables that hosts the nftables > >user HOWTO, you can reach it via: > > > > http://wiki.nftables.org > > I checked out the HOWTO and it gives a really nice concise > introduction to how nftables work. Good work! > > After browsing through the pages I have two questions: > > Is it possible to comment rules like in iptables? Comments in > iptables made it really easy to manage rules on a logical level i.e. > I could define rule "types" by adding a special comment like > "TYPE:X" and then use that to grep for these rules to batch-remove > them or retrieve the counter values. It would be nice to be able to > tag rules like this. As Arturo said, that's not yet implemented. I've been trying to find a way which doesn't involve to store that comment string in the kernel, given that this information is not used by the kernel in any way, but all what I come out with was overly complicated and not nice. So, assuming we store this comment string in kernel-space, I see several possibilities at this moment: * Add an expression for comments, which is sort of abuse since we'll iterate in nft_do_chain() over one expression which does nothing, so it adds some runtime overhead to the packet handling. This is what the iptables comment match current does, btw. * Adding a comment field to nft_rule structure, which means that we have to consume a 4/8 extra bytes in the nft_rule structure for a feature that may not be used by everyone. * Attach this this at the end of the expression data area (but *not* abusing the expression infrastructure). I think this has no runtime overhead and no extra memory consumption for those that don't need this comment feature, so it's the way to go IMO. > How do I insert multiple rules? The insertion example show the > addition of a single rule after a known handle but what if I want to > add a second rule after that? As far as I can tell from the example > the add rule command does not return the handle of the inserted rule > so I have no idea where to insert the second rule. Even if the > command returned the handle it would still require scripting to add > multiple consecutive rules so there should be a way to specify to > add a list of rules (atomically?) after a given handle. That's not yet support either. I think we'll need to keep some context information in the batch handling so you can add several list after a given handle. -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
