[PATCH bpf-next V1 4/7] net: xdp: Set skb hw metadata from xdp_frame

Jesper Dangaard Brouer
2025-06-03T17:46:20Z

From: Lorenzo Bianconi <lorenzo@kernel.org>

Update the following hw metadata provided by the NIC building the skb
from a xdp_frame.
- rx hash
- rx vlan
- rx hw-ts

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
include/net/xdp.h | 15 +++++++++++++++
net/core/xdp.c | 29 ++++++++++++++++++++++++++++-
2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index ef73f0bcc441..1ecbfe2053f2 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -310,6 +310,21 @@ xdp_frame_is_frag_pfmemalloc(const struct xdp_frame *frame)
return !!(frame->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC);
}

+static __always_inline bool xdp_frame_has_rx_meta_hash(struct xdp_frame *frame)
+{
+ return !!(frame->flags & XDP_FLAGS_META_RX_HASH);
+}
+
+static __always_inline bool xdp_frame_has_rx_meta_vlan(struct xdp_frame *frame)
+{
+ return !!(frame->flags & XDP_FLAGS_META_RX_VLAN);
+}
+
+static __always_inline bool xdp_frame_has_rx_meta_ts(struct xdp_frame *frame)
+{
+ return !!(frame->flags & XDP_FLAGS_META_RX_TS);
+}
+
#define XDP_BULK_QUEUE_SIZE 16
struct xdp_frame_bulk {
int count;
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 7d59543d7916..69077cf4c541 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -786,6 +786,23 @@ struct sk_buff *xdp_build_skb_from_zc(struct xdp_buff *xdp)
}
EXPORT_SYMBOL_GPL(xdp_build_skb_from_zc);

+static void xdp_set_skb_rx_hash_from_meta(struct xdp_frame *frame,
+ struct sk_buff *skb)
+{
+ enum pkt_hash_types hash_type = PKT_HASH_TYPE_NONE;
+
+ if (!xdp_frame_has_rx_meta_hash(frame))
+ return;
+
+ if (frame->rx_meta.hash.type & XDP_RSS_TYPE_L4_ANY)
+ hash_type = PKT_HASH_TYPE_L4;
+ else if (frame->rx_meta.hash.type & (XDP_RSS_TYPE_L3_IPV4 |
+ XDP_RSS_TYPE_L3_IPV6))
+ hash_type = PKT_HASH_TYPE_L3;
+
+ skb_set_hash(skb, frame->rx_meta.hash.val, hash_type);
+}
+
struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
struct sk_buff *skb,
struct net_device *dev)
@@ -794,11 +811,15 @@ struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
unsigned int headroom, frame_size;
void *hard_start;
u8 nr_frags;
+ u64 ts;

/* xdp frags frame */
if (unlikely(xdp_frame_has_frags(xdpf)))
nr_frags = sinfo->nr_frags;

+ if (unlikely(xdp_frame_has_rx_meta_ts(xdpf)))
+ ts = sinfo->hwtstamps.hwtstamp;
+
/* Part of headroom was reserved to xdpf */
headroom = sizeof(*xdpf) + xdpf->headroom;

@@ -826,9 +847,15 @@ struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
/* Essential SKB info: protocol and skb->dev */
skb->protocol = eth_type_trans(skb, dev);

+ xdp_set_skb_rx_hash_from_meta(xdpf, skb);
+ if (xdp_frame_has_rx_meta_vlan(xdpf))
+ __vlan_hwaccel_put_tag(skb, xdpf->rx_meta.vlan.proto,
+ xdpf->rx_meta.vlan.tci);
+ if (unlikely(xdp_frame_has_rx_meta_ts(xdpf)))
+ skb_hwtstamps(skb)->hwtstamp = ts;
+
/* Optional SKB info, currently missing:
* - HW checksum info (skb->ip_summed)
- * - HW RX hash (skb_set_hash)
* - RX ring dev queue index (skb_record_rx_queue)
*/