Hi Marcel, > > No, as usual, that would break ABI. PAD is a regular attribute, just > > empty and ignored for aligning 64-bit values. > > then I do not grok on how the nla_put_u64_64bit works, but that is > fine. > > I assumed these are similar to the NL80211_SURVEY_INFO_MAX which we > also always move, but also not expected to be part of the API as a > fixed value.
No no, the _MAX is just the token we use for knowing what we want as the maximum when parsing etc. The _PAD is actually a real attribute, basically nla_put_u64_64bit() will do "nla_put_flag(_PAD)" if and only if "offset % 8 == 0", in order to actually 64-bit align the 64-bit value in the following attribute. (Note that offset % 8 can only be 0 or 4, due to the way netlink attributes work.) johannes
