On Mon, Feb 19, 2018 at 06:09:39PM +0100, Phil Sutter wrote:
> What puzzles me about your argumentation is that you seem to propose for
> the kernel to cover up flaws in userspace. Spinning this concept further
> would mean that if there would be an old bug in iproute2 we should think
> of adding a workaround to rtnetlink interface in kernel because
> containers will keep the old iproute2 binary? Or am I (hopefully) just
> missing your point?
Actually, that's what we already do. This is from rtnl_dump_ifinfo():
/* A hack to preserve kernel<->userspace interface.
* The correct header is ifinfomsg. It is consistent with rtnl_getlink.
* However, before Linux v3.9 the code here assumed rtgenmsg and that's
* what iproute2 < v3.9.0 used.
* We can detect the old iproute2. Even including the IFLA_EXT_MASK
* attribute, its netlink message is shorter than struct ifinfomsg.
*/
(There are, in fact, even current tools using rtgenmsg but that's
another story.)
Michal Kubecek
