Re: [PATCH 00/18] xfrm: Add compat layer

Dmitry Safonov <dima(a)arista.com&gt; wrote: > So, here I add a compatible layer to xfrm. > As xfrm uses netlink notifications, kernel should send them in ABI > format that an application will parse. The proposed solution is > to save the ABI of bind() syscall. The realization detail is > to create kernel-hidden, non visible to userspace netlink groups > for compat applications. Why not use exisiting netlink support? Just add the 32bit skb to skb64->frag_list and let netlink find if tasks needs 64 or 32 one. It only needs this small fix to properly signal the end of a dump: https://marc.info/?l=linux-netdev&m=126625240303351&w=2 I had started a second attempt to make xfrm compat work, but its still in early stage. One link that might still have some value: https://git.breakpoint.cc/cgit/fw/net-next.git/commit/?h=xfrm_config_comp... (compat structure definitions with BUILD_BUG_ON checking) My plan was to make xfrm compat work strictly as shrinker (64->32) and expander (32->64), i.e. no/little changes to exisiting code and pass all "expanded" skbs through existing xfrm rcv functions.