[PATCH bpf RFC 3/4] veth: bpf_xdp_metadata_rx_hash return xdp rss hash type

Update API for bpf_xdp_metadata_rx_hash() by returning xdp rss hash type.

The veth driver currently only support XDP-hints based on SKB code path.
The SKB have lost information about the RSS hash type, by compressing
the information down to a single bitfield skb->l4_hash, that only knows
if this was a L4 hash value.

In preparation for veth, the xdp_rss_hash_type have an L4 indication
bit that allow us to return a meaningful L4 indication when working
with SKB based packets.

Signed-off-by: Jesper Dangaard Brouer <redacted>
---
 drivers/net/veth.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 046461ee42ea..6b1084e39b25 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c

@@ -1624,7 +1624,7 @@ static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
 		return -ENODATA;
 
 	*hash = skb_get_hash(_ctx->skb);
-	return 0;
+	return _ctx->skb->l4_hash ? XDP_RSS_TYPE_L4_BIT : XDP_RSS_TYPE_NONE;
 }
 
 static const struct net_device_ops veth_netdev_ops = {