From 5a89a875c96a9d038715c42f5f712002ce5124d0 Mon Sep 17 00:00:00 2001 From: Hamish Martin Date: Tue, 22 Dec 2015 10:23:58 +1300 Subject: [PATCH] staging: octeon-ethernet: fix TCP/UDP checksum calc If the network portion of a frame is preceded by more than 14 bytes of data, the checksum calculated in the HW is done over the wrong data and is put in the wrong place. In our use case an Octeon ethernet controller is connected to a Broadcom switch chip. Extra data is included in the frame prior to egressing the Octeon ethernet (i.e. 4 bytes of an 802.1Q tag, 4 bytes of a proprietary BCM tag later stripped by the switch chip). This extra data causes the checksum calculation to be incorrect. The fix in this patch is to make use of the network header offset of the skb. This enables the checksum to be calculated correctly. This has been tested in both the configuration with the switch chip in the egress path (as described above) and in a simple connection direct to the wire. Reviewed-by: Richard Laing Reviewed-by: Tim Beale Reviewed-by: Chris Packham Signed-off-by: Hamish Martin Signed-off-by: Greg Kroah-Hartman --- drivers/staging/octeon/ethernet-tx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/staging/octeon/ethernet-tx.c b/drivers/staging/octeon/ethernet-tx.c index c053c4a..5611a02 100644 --- a/drivers/staging/octeon/ethernet-tx.c +++ b/drivers/staging/octeon/ethernet-tx.c @@ -403,7 +403,7 @@ dont_put_skbuff_in_hw: ((ip_hdr(skb)->protocol == IPPROTO_TCP) || (ip_hdr(skb)->protocol == IPPROTO_UDP))) { /* Use hardware checksum calc */ - pko_command.s.ipoffp1 = sizeof(struct ethhdr) + 1; + pko_command.s.ipoffp1 = skb_network_offset(skb) + 1; } if (USE_ASYNC_IOBDMA) { -- 2.7.4