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Subject: [PATCH bpf RFC-V3 3/5] veth: bpf_xdp_metadata_rx_hash add xdp rss
 hash type
From:   Jesper Dangaard Brouer <brouer@redhat.com>
To:     bpf@vger.kernel.org, Stanislav Fomichev <sdf@google.com>
Cc:     Jesper Dangaard Brouer <brouer@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, martin.lau@kernel.org,
        ast@kernel.org, daniel@iogearbox.net, alexandr.lobakin@intel.com,
        larysa.zaremba@intel.com, xdp-hints@xdp-project.net,
        anthony.l.nguyen@intel.com, yoong.siang.song@intel.com,
        boon.leong.ong@intel.com, intel-wired-lan@lists.osuosl.org,
        pabeni@redhat.com, jesse.brandeburg@intel.com, kuba@kernel.org,
        edumazet@google.com, john.fastabend@gmail.com, hawk@kernel.org,
        davem@davemloft.net
Date:   Thu, 30 Mar 2023 19:07:55 +0200
Message-ID: <168019607588.3557870.8079404138352729694.stgit@firesoul>
In-Reply-To: <168019602958.3557870.9960387532660882277.stgit@firesoul>
References: <168019602958.3557870.9960387532660882277.stgit@firesoul>
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Update API for bpf_xdp_metadata_rx_hash() with arg for 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 <brouer@redhat.com>
---
 drivers/net/veth.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index c1178915496d..f5381e7c9310 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1648,14 +1648,19 @@ static int veth_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
 	return 0;
 }
 
-static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash)
+static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
+			    enum xdp_rss_hash_type *rss_type)
+
 {
 	struct veth_xdp_buff *_ctx = (void *)ctx;
+	struct sk_buff *skb = _ctx->skb;
 
-	if (!_ctx->skb)
+	if (!skb)
 		return -ENODATA;
 
-	*hash = skb_get_hash(_ctx->skb);
+	*hash = skb_get_hash(skb);
+	*rss_type = skb->l4_hash ? XDP_RSS_TYPE_L4_ANY : XDP_RSS_TYPE_NONE;
+
 	return 0;
 }