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Subject: [PATCH bpf V5 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>,
        =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.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, tariqt@nvidia.com
Date:   Fri, 31 Mar 2023 20:55:14 +0200
Message-ID: <168028891417.4030852.6359930131140625813.stgit@firesoul>
In-Reply-To: <168028882260.4030852.1100965689789226162.stgit@firesoul>
References: <168028882260.4030852.1100965689789226162.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.

Fixes: 306531f0249f ("veth: Support RX XDP metadata")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
---
 drivers/net/veth.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 424e8876a16b..e1b38fbf1dd9 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1652,11 +1652,14 @@ 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;
 }