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Commit 9343ac87 authored by Dave Stevenson's avatar Dave Stevenson Committed by David S. Miller
Browse files

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: default avatarDave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ec21ecf0

drivers/net/usb/lan78xx.c

+6 −1
Original line number Diff line number Diff line
@@ -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_));