From 9343ac87f2a4e09bf6e27b5f31e72e9e3a82abff Mon Sep 17 00:00:00 2001 From: Dave Stevenson Date: Mon, 25 Jun 2018 15:07:15 +0100 Subject: 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 Signed-off-by: David S. Miller --- drivers/net/usb/lan78xx.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/net') diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index 28da296f8cf7..2e4130746c40 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -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_)); -- cgit v1.2.3