On Wed, Oct 23, 2024 at 8:06 AM Willem de Bruijn
<willemdebruijn.kernel@xxxxxxxxx> wrote:
>
> Jason Xing wrote:
> > On Wed, Oct 16, 2024 at 5:56 AM Willem de Bruijn
> > <willemdebruijn.kernel@xxxxxxxxx> wrote:
> > >
> > > Martin KaFai Lau wrote:
> > > > On 10/11/24 9:06 PM, Jason Xing wrote:
> > > > > static int sol_socket_sockopt(struct sock *sk, int optname,
> > > > > char *optval, int *optlen,
> > > > > bool getopt)
> > > > > {
> > > > > + struct so_timestamping ts;
> > > > > + int ret = 0;
> > > > > +
> > > > > switch (optname) {
> > > > > case SO_REUSEADDR:
> > > > > case SO_SNDBUF:
> > > > > @@ -5225,6 +5245,13 @@ static int sol_socket_sockopt(struct sock *sk, int optname,
> > > > > break;
> > > > > case SO_BINDTODEVICE:
> > > > > break;
> > > > > + case SO_TIMESTAMPING_NEW:
> > > > > + case SO_TIMESTAMPING_OLD:
> > > >
> > > > How about remove the "_OLD" support ?
> > >
> > > +1 I forgot to mention that yesterday.
> >
> > Hello Willem, Martin,
> >
> > I did a test on this and found that if we only use
> > SO_TIMESTAMPING_NEW, we will never enter the real set sk_tsflags_bpf
> > logic, unless there is "case SO_TIMESTAMPING_OLD".
> >
> > And I checked SO_TIMESTAMPING in include/uapi/asm-generic/socket.h:
> > #if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))
> > /* on 64-bit and x32, avoid the ?: operator */
> > ...
> > #define SO_TIMESTAMPING SO_TIMESTAMPING_OLD
> > ...
> > #else
> > ...
> > #define SO_TIMESTAMPING (sizeof(time_t) == sizeof(__kernel_long_t) ?
> > SO_TIMESTAMPING_OLD : SO_TIMESTAMPING_NEW)
> > ...
> > #endif
> >
> > The SO_TIMESTAMPING is defined as SO_TIMESTAMPING_OLD. I wonder if I
> > missed something? Thanks in advance.
>
> The _NEW vs _OLD aim to deal with y2038 issues on 32-bit platforms.
>
> For new APIs, like BPF timestamping, we should always use the safe
> structs, such as timespec64.
Thanks, I learned a lot.
>
> Then we can just use SO_TIMESTAMPING without the NEW or OLD suffix.
Weird thing is that the SO_TIMESTAMPING would be converted to
SO_TIMESTAMPING_OLD in kernel if I use this :
bpf_setsockopt(skops, SOL_SOCKET, SO_TIMESTAMPING, &flags, sizeof(flags));
As I mentioned before, SO_TIMESTAMPING exists in
include/uapi/asm-generic/socket.h:
#if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__))
/* on 64-bit and x32, avoid the ?: operator */
...
#define SO_TIMESTAMPING SO_TIMESTAMPING_OLD
...
#else
...
#define SO_TIMESTAMPING (sizeof(time_t) == sizeof(__kernel_long_t) ?
SO_TIMESTAMPING_OLD : SO_TIMESTAMPING_NEW)
...
#endif
So I wonder if there is something unexpected?
BTW, I conducted the test on a VM with x86_64 cpu.
Thanks,
Jason
