Re: NLMSG_* macros (was: Re: ULOG comments)

[Andi Kleen <ak@xxxxxx>]

On Tue, Aug 15, 2000 at 05:54:03PM +0200, Jan Echternach wrote:
> [Cc'ed to netdev]
> 
> On Sat, Aug 12, 2000 at 01:22:53AM +1000, James Morris wrote:
> > The NLMSG_ macros must be used when modifing or accessing a netlink
> > bytestream.  See netlink(3) and netlink(7).
> 
> But why?  IMHO, NLMSG_* just add an uneccessary wrapper for messages
> that can't ever have multiple parts.  I don't see it as a clean
> interface in this case.

It is strongly recommended to use the NLMSG_* macros to avoid alignment problems
on other architectures than i386.

> 
> And are netlink(3) and netlink(7) really accurate for
> NETLINK_FIREWALL?  They seem to concentrate on NETLINK_ROUTE.  For
> example, both man pages refer to libnetlink which only supports
> NETLINK_ROUTE.

They are accurate as far as I know (but missing some stuff) 

> 
> Should NLMSG_* be used by netfilter targets for all kinds of netlink
> messages over NETLINK_FIREWALL or NETLINK_NFLOG type sockets?

Yes.


-Andi

-- 
This is like TV. I don't like TV.