veth: Implement VLAN tag XDP hint

JIRA: https://issues.redhat.com/browse/RHEL-31890

Upstream commit(s):
commit fca7837
Author: Larysa Zaremba <larysa.zaremba@intel.com>
Date:   Tue Dec 5 22:08:41 2023 +0100

    veth: Implement VLAN tag XDP hint

    In order to test VLAN tag hint in hardware-independent selftests, implement
    newly added hint in veth driver.

    Acked-by: Stanislav Fomichev <sdf@google.com>
    Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
    Link: https://lore.kernel.org/r/20231205210847.28460-13-larysa.zaremba@intel.com
    Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Signed-off-by: Petr Oros <poros@redhat.com>

Author: orosp

drivers/net/veth.c

@@ -1683,6 +1683,24 @@ static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
 	return 0;
 }
 
+static int veth_xdp_rx_vlan_tag(const struct xdp_md *ctx, __be16 *vlan_proto,
+				u16 *vlan_tci)
+{
+	const struct veth_xdp_buff *_ctx = (void *)ctx;
+	const struct sk_buff *skb = _ctx->skb;
+	int err;
+
+	if (!skb)
+		return -ENODATA;
+
+	err = __vlan_hwaccel_get_tag(skb, vlan_tci);
+	if (err)
+		return err;
+
+	*vlan_proto = skb->vlan_proto;
+	return err;
+}
+
 static const struct net_device_ops veth_netdev_ops = {
 	.ndo_init            = veth_dev_init,
 	.ndo_open            = veth_open,
@@ -1707,6 +1725,7 @@ static const struct net_device_ops veth_netdev_ops = {
 static const struct xdp_metadata_ops veth_xdp_metadata_ops = {
 	.xmo_rx_timestamp		= veth_xdp_rx_timestamp,
 	.xmo_rx_hash			= veth_xdp_rx_hash,
+	.xmo_rx_vlan_tag		= veth_xdp_rx_vlan_tag,
 };
 
 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \