On Sun, Oct 13, 2024 at 09:43:19PM +0200, Pablo Neira Ayuso wrote:
> This function is modelled after rta_getattr_uint() in libnetlink to fetch the
> netlink attribute payload of NLA_UINT, although it was extended to make it
> universal for 8-bit, 16-bit, 32-bit and 64-bit integers.
>
> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> ---
> v2: fix reference to bytes instead of bits per Phil Sutter.
>
> src/attr.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/src/attr.c b/src/attr.c
> index 399318eebaa8..20e99b195ab7 100644
> --- a/src/attr.c
> +++ b/src/attr.c
> @@ -393,7 +393,24 @@ EXPORT_SYMBOL uint64_t mnl_attr_get_u64(const struct nlattr *attr)
> * mnl_attr_get_uint - returns 64-bit unsigned integer attribute.
> * \param attr pointer to netlink attribute
> *
> - * This function returns the 64-bit value of the attribute payload.
> + * This helper function reads the variable-length netlink attribute NLA_UINT
> + * that provides a 32-bit or 64-bit integer payload. Its use is recommended only
> + * in these cases.
> + *
> + * Recommended validation for NLA_UINT is:
> + *
> + * \verbatim
> + if (!mnl_attr_validate(attr, NLA_U32) &&
> + !mnl_attr_validate(attr, NLA_U64)) {
> + perror("mnl_attr_validate");
> + return MNL_CB_ERROR;
> + }
> +\endverbatim
> + *
> + * \returns the 64-bit value of the attribute payload. On error, it returns
> + * UINT64_MAX if the length of the netlink attribute is not an 8-bit, 16-bit,
> + * 32-bit and 64-bit integer. Therefore, there is no way to distinguish between
~~~
Nit: This should be "or", since the length is expected to be either one
of the listed values.
That aside:
Acked-by: Phil Sutter <phil@xxxxxx>
Thanks!
