packet: tx timestamping on tpacket ring

When transmit timestamping is enabled at the socket level, record a
timestamp on packets written to a PACKET_TX_RING. Tx timestamps are
always looped to the application over the socket error queue. Software
timestamps are also written back into the packet frame header in the
packet ring.

Reported-by: Paul Chavent <paul.chavent@onera.fr>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 6 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 898cf5c566f9..af9185d0be6a 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3327,12 +3327,8 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
         if (!sk)
                 return;
 
-        skb = skb_clone(orig_skb, GFP_ATOMIC);
-        if (!skb)
-                return;
-
         if (hwtstamps) {
-                *skb_hwtstamps(skb) =
+                *skb_hwtstamps(orig_skb) =
                         *hwtstamps;
         } else {
                 /*
@@ -3340,9 +3336,13 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
                  * so keep the shared tx_flags and only
                  * store software time stamp
                  */
-                skb->tstamp = ktime_get_real();
+                orig_skb->tstamp = ktime_get_real();
         }
 
+        skb = skb_clone(orig_skb, GFP_ATOMIC);
+        if (!skb)
+                return;
+
         serr = SKB_EXT_ERR(skb);
         memset(serr, 0, sizeof(*serr));
         serr->ee.ee_errno = ENOMSG;