[PATCH net-next 3/4] i40e: add support for bpf_xdp_metadata_rx_vlan_tag()

[Tony Nguyen <anthony.l.nguyen@intel.com>]

From: Kohei Enju <kohei@enjuk.jp>

Introduce i40e_xdp_rx_vlan_tag() which takes the same approach as
i40e_process_skb_fields() to extract the VLAN tag from the RX
descriptor.

Tested with X710 adapter using xdp_hw_metadata, and confirmed that VLAN
tags match between bpf_xdp_metadata_rx_vlan_tag() and
skb->vlan_proto/vlan_tci.

Signed-off-by: Kohei Enju <kohei@enjuk.jp>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Patryk Holda <patryk.holda@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index e487d697a634..719f45b5cb40 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -13607,8 +13607,27 @@ static int i40e_xdp_rx_hash(const struct xdp_md *_ctx, u32 *hash,
 	return 0;
 }
 
+static int i40e_xdp_rx_vlan_tag(const struct xdp_md *_ctx, __be16 *vlan_proto,
+				u16 *vlan_tci)
+{
+	const struct i40e_xdp_buff *ctx = (const void *)_ctx;
+	const union i40e_rx_desc *desc = ctx->desc;
+	u64 status;
+
+	status = le64_to_cpu(desc->wb.qword1.status_error_len);
+
+	if (!(status & BIT(I40E_RX_DESC_STATUS_L2TAG1P_SHIFT)))
+		return -ENODATA;
+
+	*vlan_proto = cpu_to_be16(ETH_P_8021Q);
+	*vlan_tci = le16_to_cpu(desc->wb.qword0.lo_dword.l2tag1);
+
+	return 0;
+}
+
 static const struct xdp_metadata_ops i40e_xdp_metadata_ops = {
 	.xmo_rx_hash		= i40e_xdp_rx_hash,
+	.xmo_rx_vlan_tag	= i40e_xdp_rx_vlan_tag,
 };
 
 static const struct net_device_ops i40e_netdev_ops = {
-- 
2.47.1