On Mon, 2019-04-29 at 22:49 -0400, David Miller wrote:
> From: Johannes Berg <johan...@sipsolutions.net>
> Date: Fri, 26 Apr 2019 14:13:02 +0200
>
> > * NLA_POLICY_RANGE() macros.
> > + * NLA_U8,
> > + * NLA_U16,
> > + * NLA_U32,
> > + * NLA_U64 If the validation_type field instead is set to
> > + * NLA_VALIDATE_RANGE_PTR, `range' must be a
> > pointer
> > + * to a struct netlink_range_validation that
> > indicates
> > + * the min/max values.
> > + * Use NLA_POLICY_FULL_RANGE().
> > + * NLA_S8,
> > + * NLA_S16,
> > + * NLA_S32,
> > + * NLA_S64 If the validation_type field instead is set to
> > + * NLA_VALIDATE_RANGE_PTR, `range_signed' must be a
> > + * pointer to a struct
> > netlink_range_validation_signed
> > + * that indicates the min/max values.
> > + * Use NLA_POLICY_FULL_RANGE_SIGNED().
>
> Documentation and datastructure says that "range_signed" member should be set
> for signed ranges, however:
>
> > +#define NLA_POLICY_FULL_RANGE(tp, _range) { \
> > + .type = NLA_ENSURE_UINT_TYPE(tp), \
> > + .validation_type = NLA_VALIDATE_RANGE_PTR, \
> > + .range = _range, \
> > +}
> > +
> > +#define NLA_POLICY_FULL_RANGE_SIGNED(tp, _range) { \
> > + .type = NLA_ENSURE_SINT_TYPE(tp), \
> > + .validation_type = NLA_VALIDATE_RANGE_PTR, \
> > + .range = _range, \
> > +}
>
> The NLA_POLICY_FULL_RANGE_SIGNED macros sets 'range' not 'range_signed'.
D'oh. Copy/paste error, and I must've missed the compiler warning that
should appear here on usage then. At least I'm pretty sure I tested that
with the policy exposition patch.
Will fix.
> Also, since range and range_signed are in a union however there is only one
> NLA_VALIDATE_RANGE_PTR type, how does one differentiate between signed and
> unsigned ranges exactly?
Based on the type - NLA_S* or NLA_U*. See the NLA_ENSURE_SINT_TYPE() and
NLA_ENSURE_UINT_TYPE() in the macros - that ensures you can only use
NLA_POLICY_FULL_RANGE_SIGNED() with NLA_S*, and NLA_POLICY_FULL_RANGE()
with NLA_U*.
johannes
