[NET]: Introduce SIOCGSTAMPNS ioctl to get timestamps with nanosec resolution

Now network timestamps use ktime_t infrastructure, we can add a new
ioctl() SIOCGSTAMPNS command to get timestamps in 'struct timespec'.
User programs can thus access to nanosecond resolution.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
CC: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index f9866a8..6f8c72d 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1545,6 +1545,8 @@
 		}
 		case SIOCGSTAMP:
 			return sock_get_timestamp(sk, (struct timeval __user *)arg);
+		case SIOCGSTAMPNS:
+			return sock_get_timestampns(sk, (struct timespec __user *)arg);
 
 #ifdef CONFIG_INET
 		case SIOCADDRT: