[PATCH] net/af_xdp: add Rx metadata and dynamic timestamping support

[PATCH] net/af_xdp: add Rx metadata and dynamic timestamping support

[Mark Blasko]

Enable dynamic RX timestamping in the AF_XDP Poll Mode Driver.
This extracts the ingress timestamp prepended to the packet
headroom by the XDP program and populates it in the mbuf.

Signed-off-by: Mark Blasko <blasko@google.com>
Reviewed-by: Joshua Washington <joshwash@google.com>
Reviewed-by: Jasper Tran O'Leary <jtranoleary@google.com>
---
 doc/guides/rel_notes/release_26_07.rst |  5 +++
 drivers/net/af_xdp/rte_eth_af_xdp.c    | 56 +++++++++++++++++++++++++-
 2 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/doc/guides/rel_notes/release_26_07.rst b/doc/guides/rel_notes/release_26_07.rst
index 6eba91a5e9..727442258f 100644
--- a/doc/guides/rel_notes/release_26_07.rst
+++ b/doc/guides/rel_notes/release_26_07.rst
@@ -63,6 +63,11 @@ New Features
     ``rte_eal_init`` and the application is responsible for probing each device,
   * ``--auto-probing`` enables the initial bus probing, which is the current default behavior.
 
+* **Updated AF_XDP ethernet driver.**
+
+  * Added support for dynamic RX metadata and timestamping offload
+    (``RTE_ETH_RX_OFFLOAD_TIMESTAMP``).
+
 * **Added LinkData sxe2 ethernet driver.**
 
   Added network driver for the LinkData network adapters.
diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c
index 2cdb533276..c90e232d57 100644
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -62,6 +62,13 @@
 #define PF_XDP AF_XDP
 #endif
 
+struct af_xdp_rx_metadata {
+	uint64_t rx_timestamp;
+};
+
+static int timestamp_dynfield_offset = -1;
+static uint64_t timestamp_dynflag;
+
 RTE_LOG_REGISTER_DEFAULT(af_xdp_logtype, NOTICE);
 #define RTE_LOGTYPE_NET_AF_XDP af_xdp_logtype
 
@@ -144,6 +151,7 @@ struct pkt_rx_queue {
 	struct pollfd fds[1];
 	int xsk_queue_idx;
 	int busy_budget;
+	bool rx_timestamp_enabled;
 };
 
 struct tx_stats {
@@ -398,6 +406,20 @@ af_xdp_rx_zc(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 
 		rte_pktmbuf_pkt_len(bufs[i]) = len;
 		rte_pktmbuf_data_len(bufs[i]) = len;
+
+		if (rxq->rx_timestamp_enabled &&
+		    timestamp_dynfield_offset >= 0) {
+			struct af_xdp_rx_metadata *meta;
+
+			meta = (struct af_xdp_rx_metadata *)
+				((char *)rte_pktmbuf_mtod(bufs[i], void *) -
+				 sizeof(struct af_xdp_rx_metadata));
+			*RTE_MBUF_DYNFIELD(bufs[i],
+					   timestamp_dynfield_offset,
+					   uint64_t *) = meta->rx_timestamp;
+			bufs[i]->ol_flags |= timestamp_dynflag;
+		}
+
 		rx_bytes += len;
 	}
 
@@ -457,6 +479,18 @@ af_xdp_rx_cp(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 		len = desc->len;
 		pkt = xsk_umem__get_data(rxq->umem->mz->addr, addr);
 
+		if (rxq->rx_timestamp_enabled &&
+		    timestamp_dynfield_offset >= 0) {
+			struct af_xdp_rx_metadata *meta;
+
+			meta = (struct af_xdp_rx_metadata *)((char *)pkt -
+				sizeof(struct af_xdp_rx_metadata));
+			*RTE_MBUF_DYNFIELD(mbufs[i],
+					   timestamp_dynfield_offset,
+					   uint64_t *) = meta->rx_timestamp;
+			mbufs[i]->ol_flags |= timestamp_dynflag;
+		}
+
 		rte_memcpy(rte_pktmbuf_mtod(mbufs[i], void *), pkt, len);
 		rte_ring_enqueue(umem->buf_ring, (void *)addr);
 		rte_pktmbuf_pkt_len(mbufs[i]) = len;
@@ -743,6 +777,23 @@ eth_dev_start(struct rte_eth_dev *dev)
 {
 	uint16_t i;
 
+	if (dev->data->dev_conf.rxmode.offloads &
+	    RTE_ETH_RX_OFFLOAD_TIMESTAMP) {
+		int rc;
+
+		rc = rte_mbuf_dyn_rx_timestamp_register(
+				&timestamp_dynfield_offset,
+				&timestamp_dynflag);
+		if (rc) {
+			AF_XDP_LOG_LINE(ERR,
+				"Failed to register mbuf timestamp field");
+			return rc;
+		}
+		AF_XDP_LOG_LINE(INFO,
+			"Registered mbuf timestamp field, offset: %d",
+			timestamp_dynfield_offset);
+	}
+
 	dev->data->dev_link.link_status = RTE_ETH_LINK_UP;
 	for (i = 0; i < dev->data->nb_rx_queues; i++) {
 		dev->data->rx_queue_state[i] = RTE_ETH_QUEUE_STATE_STARTED;
@@ -870,6 +921,8 @@ eth_dev_info(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 	dev_info->max_rx_queues = internals->queue_cnt;
 	dev_info->max_tx_queues = internals->queue_cnt;
 
+	dev_info->rx_offload_capa = RTE_ETH_RX_OFFLOAD_TIMESTAMP;
+
 	dev_info->min_mtu = RTE_ETHER_MIN_MTU;
 #if defined(XDP_UMEM_UNALIGNED_CHUNK_FLAG)
 	dev_info->max_rx_pktlen = getpagesize() -
@@ -1873,7 +1926,8 @@ eth_rx_queue_setup(struct rte_eth_dev *dev,
 	process_private->rxq_xsk_fds[rx_queue_id] = rxq->fds[0].fd;
 
 	rxq->port = dev->data->port_id;
-
+	rxq->rx_timestamp_enabled = !!(dev->data->dev_conf.rxmode.offloads &
+					RTE_ETH_RX_OFFLOAD_TIMESTAMP);
 	dev->data->rx_queues[rx_queue_id] = rxq;
 	return 0;
 
-- 
2.55.0.rc0.799.gd6f94ed593-goog

Re: [PATCH] net/af_xdp: add Rx metadata and dynamic timestamping support

[Stephen Hemminger]

On Tue, 23 Jun 2026 21:53:24 +0000
Mark Blasko <blasko@google.com> wrote:

> +		if (rxq->rx_timestamp_enabled &&
> +		    timestamp_dynfield_offset >= 0) {
> +			struct af_xdp_rx_metadata *meta;
> +
> +			meta = (struct af_xdp_rx_metadata *)
> +				((char *)rte_pktmbuf_mtod(bufs[i], void *) -
> +				 sizeof(struct af_xdp_rx_metadata));
> +			*RTE_MBUF_DYNFIELD(bufs[i],
> +					   timestamp_dynfield_offset,
> +					   uint64_t *) = meta->rx_timestamp;
> +			bufs[i]->ol_flags |= timestamp_dynflag;
> +		}
> +

Why does XDP time stamp need to be different than how other drivers
already do timestamps. See AF_PACKET and TAP device?

Should not be driver specific here.