net-timestamp: sock_tx_timestamp() fix

sock_tx_timestamp() should not ignore initial *tx_flags value, as TCP
stack can store SKBTX_SHARED_FRAG in it.

Also first argument (struct sock *) can be const.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 4ed2d765dfac ("net-timestamp: TCP timestamping")
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 7 deletions

diff --git a/net/socket.c b/net/socket.c
index ae89569a2db5..95ee7d8682e7 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -610,20 +610,26 @@ void sock_release(struct socket *sock)
 }
 EXPORT_SYMBOL(sock_release);
 
-void sock_tx_timestamp(struct sock *sk, __u8 *tx_flags)
+void sock_tx_timestamp(const struct sock *sk, __u8 *tx_flags)
 {
-        *tx_flags = 0;
+        u8 flags = *tx_flags;
+
         if (sk->sk_tsflags & SOF_TIMESTAMPING_TX_HARDWARE)
-                *tx_flags |= SKBTX_HW_TSTAMP;
+                flags |= SKBTX_HW_TSTAMP;
+
         if (sk->sk_tsflags & SOF_TIMESTAMPING_TX_SOFTWARE)
-                *tx_flags |= SKBTX_SW_TSTAMP;
+                flags |= SKBTX_SW_TSTAMP;
+
         if (sk->sk_tsflags & SOF_TIMESTAMPING_TX_SCHED)
-                *tx_flags |= SKBTX_SCHED_TSTAMP;
+                flags |= SKBTX_SCHED_TSTAMP;
+
         if (sk->sk_tsflags & SOF_TIMESTAMPING_TX_ACK)
-                *tx_flags |= SKBTX_ACK_TSTAMP;
+                flags |= SKBTX_ACK_TSTAMP;
 
         if (sock_flag(sk, SOCK_WIFI_STATUS))
-                *tx_flags |= SKBTX_WIFI_STATUS;
+                flags |= SKBTX_WIFI_STATUS;
+
+        *tx_flags = flags;
 }
 EXPORT_SYMBOL(sock_tx_timestamp);