net: lan78xx: Use s/w csum check on VLANs without tag stripping

Observations of VLANs dropping packets due to invalid
checksums when not offloading VLAN tag receive.
With VLAN tag stripping enabled no issue is observed.

Drop back to s/w checksums if VLAN offload is disabled.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dave Stevenson 2018-06-25 15:07:15 +01:00 committed by David S. Miller
parent ec21ecf0aa
commit 9343ac87f2

View File

@ -3052,8 +3052,13 @@ static void lan78xx_rx_csum_offload(struct lan78xx_net *dev,
struct sk_buff *skb,
u32 rx_cmd_a, u32 rx_cmd_b)
{
/* HW Checksum offload appears to be flawed if used when not stripping
* VLAN headers. Drop back to S/W checksums under these conditions.
*/
if (!(dev->net->features & NETIF_F_RXCSUM) ||
unlikely(rx_cmd_a & RX_CMD_A_ICSM_)) {
unlikely(rx_cmd_a & RX_CMD_A_ICSM_) ||
((rx_cmd_a & RX_CMD_A_FVTG_) &&
!(dev->net->features & NETIF_F_HW_VLAN_CTAG_RX))) {
skb->ip_summed = CHECKSUM_NONE;
} else {
skb->csum = ntohs((u16)(rx_cmd_b >> RX_CMD_B_CSUM_SHIFT_));