[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>

1 files changed, 16 insertions, 0 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index 6ddb3664b993..cb48fa0e1249 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1567,6 +1567,22 @@ int sock_get_timestamp(struct sock *sk, struct timeval __user *userstamp)
 }
 EXPORT_SYMBOL(sock_get_timestamp);
 
+int sock_get_timestampns(struct sock *sk, struct timespec __user *userstamp)
+{
+        struct timespec ts;
+        if (!sock_flag(sk, SOCK_TIMESTAMP))
+                sock_enable_timestamp(sk);
+        ts = ktime_to_timespec(sk->sk_stamp);
+        if (ts.tv_sec == -1)
+                return -ENOENT;
+        if (ts.tv_sec == 0) {
+                sk->sk_stamp = ktime_get_real();
+                ts = ktime_to_timespec(sk->sk_stamp);
+        }
+        return copy_to_user(userstamp, &ts, sizeof(ts)) ? -EFAULT : 0;
+}
+EXPORT_SYMBOL(sock_get_timestampns);
+
 void sock_enable_timestamp(struct sock *sk)
 {
         if (!sock_flag(sk, SOCK_TIMESTAMP)) {