[NET]: Adding SO_TIMESTAMPNS / SCM_TIMESTAMPNS support

Now that network timestamps use ktime_t infrastructure, we can add a new
SOL_SOCKET sockopt  SO_TIMESTAMPNS.

This command is similar to SO_TIMESTAMP, but permits transmission of
a 'timespec struct' instead of a 'timeval struct' control message.
(nanosecond resolution instead of microsecond)

Control message is labelled SCM_TIMESTAMPNS instead of SCM_TIMESTAMP

A socket cannot mix SO_TIMESTAMP and SO_TIMESTAMPNS : the two modes are
mutually exclusive.

sock_recv_timestamp() became too big to be fully inlined so I added a
__sock_recv_timestamp() helper function.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
CC: linux-arch@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 10 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 51246579592e..390c04700590 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -390,6 +390,7 @@ enum sock_flags {
         SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
         SOCK_DBG, /* %SO_DEBUG setting */
         SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
+        SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
         SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
         SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
 };
@@ -1283,21 +1284,17 @@ static inline int sock_intr_errno(long timeo)
         return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
 }
 
+extern void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
+        struct sk_buff *skb);
+
 static __inline__ void
 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
 {
         ktime_t kt = skb->tstamp;
 
-        if (sock_flag(sk, SOCK_RCVTSTAMP)) {
-                struct timeval tv;
-                /* Race occurred between timestamp enabling and packet
-                   receiving.  Fill in the current time for now. */
-                if (kt.tv64 == 0)
-                        kt = ktime_get_real();
-                skb->tstamp = kt;
-                tv = ktime_to_timeval(kt);
-                put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP, sizeof(tv), &tv);
-        } else
+        if (sock_flag(sk, SOCK_RCVTSTAMP))
+                __sock_recv_timestamp(msg, sk, skb);
+        else
                 sk->sk_stamp = kt;
 }