Re: [PATCH libmnl v2 2/2] libmnl: add support for signed types

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Mon, Aug 08, 2022 at 05:46:50PM +0000, Keller, Jacob E wrote:
> 
> 
> > -----Original Message-----
> > From: Pablo Neira Ayuso <pablo@netfilter.org>
> > Sent: Monday, August 08, 2022 7:09 AM
> > To: Keller, Jacob E <jacob.e.keller@intel.com>
> > Cc: Netfilter Devel <netfilter-devel@vger.kernel.org>; Duncan Roe
> > <duncan_roe@optusnet.com.au>
> > Subject: Re: [PATCH libmnl v2 2/2] libmnl: add support for signed types
> > 
> > Hi,
> > 
> > On Fri, Aug 05, 2022 at 02:00:40PM -0700, Jacob Keller wrote:
> > > libmnl has get and put functions for unsigned integer types. It lacks
> > > support for the signed variations. On some level this is technically
> > > sufficient. A user could use the unsigned variations and then cast to a
> > > signed value at use. However, this makes resulting code in the application
> > > more difficult to follow. Introduce signed variations of the integer get
> > > and put functions.
> > >
> > > Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> > > ---
> > >  include/libmnl/libmnl.h |  16 ++++
> > >  src/attr.c              | 194 +++++++++++++++++++++++++++++++++++++++-
> > >  2 files changed, 209 insertions(+), 1 deletion(-)
> > >
> > [...]
> > > @@ -127,6 +139,10 @@ enum mnl_attr_data_type {
> > >  	MNL_TYPE_U16,
> > >  	MNL_TYPE_U32,
> > >  	MNL_TYPE_U64,
> > > +	MNL_TYPE_S8,
> > > +	MNL_TYPE_S16,
> > > +	MNL_TYPE_S32,
> > > +	MNL_TYPE_S64,
> > 
> > This breaks ABI, you have to add new types at the end of the
> > enumeration.
> > 
> 
> To clarify, I believe this would be at the end just before MNL_TYPE_MAX?

Right after MNL_TYPE_BINARY, it is ok to update MNL_TYPE_MAX.