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: 80b14dee2bea ("net: Add a new socket option for a future transmit time.")
Fixes: fb420d5d91c1 ("tcp/fq: move back to CLOCK_MONOTONIC")
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Willem de Bruijn <will...@google.com>
Cc: Soheil Hassas Yeganeh <soh...@google.com>
---
drivers/net/loopback.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index
a7207fa7e451311aed13cdeb100e0ea7922931bf..2df7f60fe05220c19896a251b6b15239f4b95112
100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -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(),
--
2.19.1.568.g152ad8e336-goog
