Re: [net-next PATCH 11/11] net: ravb: Add VLAN checksum support

Sergey Shtylyov
2024-09-30T22:32:47Z

On 9/30/24 23:36, Sergey Shtylyov wrote:
[...]

>> From: Paul Barker <paul.barker.ct@bp.renesas.com>
>>
>> The GbEth IP supports offloading checksum calculation for VLAN-tagged
>> packets, provided that the EtherType is 0x8100 and only one VLAN tag is
>> present.
>>
>> Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
> [...]
>
>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>> index 832132d44fb4..eb7499d42a9b 100644
>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
>> @@ -2063,11 +2063,30 @@ static void ravb_tx_timeout_work(struct work_struct *work)
[...]
>> - switch (ntohs(skb->protocol)) {
>> + if (net_protocol == ETH_P_8021Q) {
>> + struct vlan_hdr vhdr, *vh;
>> +
>> + vh = skb_header_pointer(skb, ETH_HLEN, sizeof(vhdr), &vhdr);
>
> Hm, I thought the VLAN header starts at ETH_HLEN - 2, not at ETH_HLEN...

Wikipedia indeed says that the VLAN header begins with TPID word (0x8100)
and then the TCI word follows -- while in Linux, *struct* vlan_hgr starts with
the TCI word -- hence my confusion... :-)

> [...]

MBR, Sergey