Re: libnetfilter_*: Use uint*_t instead of u_int*_t

[Felix Janda <felix.janda@posteo.de>]

Pablo Neira Ayuso wrote:
> On Fri, May 15, 2015 at 09:10:39PM +0200, Felix Janda wrote:
> > Hello,
> > 
> > I've been trying to build many netfilter.org projects on a system with
> > the musl libc library. Alas, I often get errors about undeclared
> > u_int8_t, ... musl will declare these types when <sys/types.h> is
> > included and _GNU_SOURCE or _BSD_SOURCE is set. However many
> > netfilter.org projects don't include <sys/types.h>.
> 
> I suspected this when I applied the patch from the Alpine Linux guy
> for libnetfilter_log just a while.

libnetfilter_log compiles fine right now (except for libipulog). I would
however change the types there as well for consistency.

Hmm, actually of the libraries only libnfnetlink is problematic, I have
seen the errors mostly when trying to compile the applications.
(arptables, ebtables, conntrack-tools, possibly also ulogd2)

> > On the other hand, changing the types to the <stdint.h> uint*_t works
> > in most cases because <netinet/in.h> is often included, which (by POSIX)
> > includes <inttypes.h> which includes <stdint.h>. (Sometimes <stdint.h> or
> > <inttypes.h> is also directly included.)
> 
> Last time I looked into this, my conclusion was that it was safe to
> migrate to uint*_t stdint types, but it would be good to double check.
> 
> > In some cases u_int*_t and uint*_t types are mixed, so I am going to
> > prepare a patch series which changing them and making sure that the
> > public headers explicitly include <stdint.h> if they use these types.
> > 
> > Assuming these (relatively invasive in terms of changed lines of code)
> > changes are acceptable, I have some questions:
> > 
> > Are the linux_nfnetlink_*.h only used as includes from other headers?
> > (so that they don't need an explicit #include <stdint.h>)
> 
> You can refresh those header files to get them in sync with the
> kernel, that can come in several initial patches. They are cached
> copies of what we have in the kernel, as a result you'll get __u*
> types.
> 
> Then, the follow up patch can convert them to uint*

ok.

> > Is there anything I need to be careful about?
> > 
> > There are also kernel types (e.g. __u8) in some places. Should I also
> > bother about these while I'm at it? These were not problematic for me
> > since these (mostly?) kernel headers include <linux/types.h>.
> 
> Those should remain there, as they are part of a cached copy of what
> we have in the linux kernel tree. The idea is basically to ensure
> compilation of libraries independently of what linux headers you have
> in your system (eg. people with very old header files).

ok.

Felix