Re: [PATCH V2 net-next 4/6] tun: Add support for SCTP checksum offload

On 05/02/2018 10:56 AM, Marcelo Ricardo Leitner wrote:

On Wed, May 02, 2018 at 11:53:47AM -0300, Marcelo Ricardo Leitner wrote:

quoted

On Tue, May 01, 2018 at 10:07:37PM -0400, Vladislav Yasevich wrote:

quoted

Adds a new tun offload flag to allow for SCTP checksum offload.
The flag has to be set by the user and defaults to "no offload".

I'm confused here:

quoted

+++ b/drivers/net/tun.c

@@ -216,7 +216,7 @@ struct tun_struct {
 	struct net_device	*dev;
 	netdev_features_t	set_features;
 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
-			  NETIF_F_TSO6)
+			  NETIF_F_TSO6|NETIF_F_SCTP_CRC)

Doesn't adding it here mean it defaults to "offload", instead?

later on, it does:
                dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
                                   TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
                                   NETIF_F_HW_VLAN_STAG_TX;

Missed to paste the next line too:
                dev->features = dev->hw_features | NETIF_F_LLTX;

Yes, as a software device, we can default it to on.  However, qemu will 0-out
the features and then set them up based on the guest (just like regular checksum).

-vlad