net: loopback: clear skb->tstamp before netif_rx()
authorEric Dumazet <edumazet@google.com>
Sat, 20 Oct 2018 02:11:26 +0000 (19:11 -0700)
committerDavid S. Miller <davem@davemloft.net>
Sat, 20 Oct 2018 08:01:28 +0000 (01:01 -0700)
At least UDP / TCP stacks can now cook skbs with a tstamp using
MONOTONIC base (or arbitrary values with SCM_TXTIME)

Since loopback driver does not call (directly or indirectly)
skb_scrub_packet(), we need to clear skb->tstamp so that
net_timestamp_check() can eventually resample the time,
using ktime_get_real().

Fixes: 0ac40e4e9536 ("net: Add a new socket option for a future transmit time.")
Fixes: fff99772a27e ("tcp/fq: move back to CLOCK_MONOTONIC")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/loopback.c

index a7207fa7e451311aed13cdeb100e0ea7922931bf..2df7f60fe05220c19896a251b6b15239f4b95112 100644 (file)
@@ -69,6 +69,10 @@ static netdev_tx_t loopback_xmit(struct sk_buff *skb,
        int len;
 
        skb_tx_timestamp(skb);
+
+       /* do not fool net_timestamp_check() with various clock bases */
+       skb->tstamp = 0;
+
        skb_orphan(skb);
 
        /* Before queueing this packet to netif_rx(),