socket: fix option SO_TIMESTAMPING_NEW

The comparison of optname with SO_TIMESTAMPING_NEW is wrong way around,
so SOCK_TSTAMP_NEW will first be set and than reset again. Additionally
move it out of the test for SOF_TIMESTAMPING_RX_SOFTWARE as this seems
unrelated.

This problem happens on 32 bit platforms were the libc has already
switched to struct timespec64 (from SO_TIMExxx_OLD to SO_TIMExxx_NEW
socket options). ptp4l complains with "missing timestamp on transmitted
peer delay request" because the wrong format is received (and
discarded).

Fixes: 9718475e ("socket: Add SO_TIMESTAMPING_NEW")
Signed-off-by: Christian Eggers <ceggers@arri.de>
Reviewed-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Reviewed-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/sock.c

@@ -1007,8 +1007,6 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 		__sock_set_timestamps(sk, valbool, true, true);
 		break;
 	case SO_TIMESTAMPING_NEW:
-		sock_set_flag(sk, SOCK_TSTAMP_NEW);
-		fallthrough;
 	case SO_TIMESTAMPING_OLD:
 		if (val & ~SOF_TIMESTAMPING_MASK) {
 			ret = -EINVAL;
@@ -1037,16 +1035,14 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 		}
 
 		sk->sk_tsflags = val;
+		sock_valbool_flag(sk, SOCK_TSTAMP_NEW, optname == SO_TIMESTAMPING_NEW);
+
 		if (val & SOF_TIMESTAMPING_RX_SOFTWARE)
 			sock_enable_timestamp(sk,
 					      SOCK_TIMESTAMPING_RX_SOFTWARE);
-		else {
-			if (optname == SO_TIMESTAMPING_NEW)
-				sock_reset_flag(sk, SOCK_TSTAMP_NEW);
-
+		else
 			sock_disable_timestamp(sk,
 					       (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE));
-		}
 		break;
 
 	case SO_RCVLOWAT: