[PATCH v3] net/af_packet: add timestamp offloading support

[Stefan Laesser <stefan.laesser@omicronenergy.com>]

Add the packet timestamp from TPACKET_V2 to the mbuf
dynamic rx timestamp register if offload RTE_ETH_RX_OFFLOAD_TIMESTAMP
is enabled.

TPACKET_V2 provides the timestamp with nanosecond resolution
and UNIX origo, i.e. time since 1-JAN-1970 UTC.

Signed-off-by: Stefan Laesser <stefan.laesser@omicronenergy.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
---

v3:
* fixed compilation errors

v2:
* mentioned that timestamp is since 1-JAN-1970 UTC
* made the two timestamp_dynflag variables private and removed prefix
* undo moving of counter variable in eth_dev_start() to reduce code changes

 .mailmap                                  |  1 +
 doc/guides/nics/af_packet.rst             |  8 +++---
 drivers/net/af_packet/rte_eth_af_packet.c | 30 ++++++++++++++++++++++-
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/.mailmap b/.mailmap
index 4a508bafad..69314e34a0 100644
--- a/.mailmap
+++ b/.mailmap
@@ -1414,6 +1414,7 @@ Steeven Lee <steeven@gmail.com>
 Steeven Li <steeven.li@broadcom.com>
 Stefan Baranoff <sbaranoff@gmail.com>
 Stefan Hajnoczi <stefanha@redhat.com>
+Stefan Laesser <stefan.laesser@omicronenergy.com>
 Stefan Puiu <stefan.puiu@gmail.com>
 Stefan Wegrzyn <stefan.wegrzyn@intel.com>
 Stepan Sojka <stepan.sojka@adaptivemobile.com>
diff --git a/doc/guides/nics/af_packet.rst b/doc/guides/nics/af_packet.rst
index 66b977e1a2..a343d3a961 100644
--- a/doc/guides/nics/af_packet.rst
+++ b/doc/guides/nics/af_packet.rst
@@ -69,6 +69,8 @@ framecnt=512):
 Features and Limitations
 ------------------------
 
-The PMD will re-insert the VLAN tag transparently to the packet if the kernel
-strips it, as long as the ``RTE_ETH_RX_OFFLOAD_VLAN_STRIP`` is not enabled by the
-application.
+*  The PMD will re-insert the VLAN tag transparently to the packet if the kernel
+   strips it, as long as the ``RTE_ETH_RX_OFFLOAD_VLAN_STRIP`` is not enabled by the
+   application.
+*  The PMD will add the kernel packet timestamp with nanoseconds resolution and
+   UNIX origo, i.e. time since 1-JAN-1970 UTC, if ``RTE_ETH_RX_OFFLOAD_TIMESTAMP`` is enabled.
diff --git a/drivers/net/af_packet/rte_eth_af_packet.c b/drivers/net/af_packet/rte_eth_af_packet.c
index 6b7b16f348..d532105745 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -40,6 +40,9 @@
 #define DFLT_FRAME_SIZE		(1 << 11)
 #define DFLT_FRAME_COUNT	(1 << 9)
 
+static uint64_t timestamp_dynflag;
+static int timestamp_dynfield_offset = -1;
+
 struct __rte_cache_aligned pkt_rx_queue {
 	int sockfd;
 
@@ -51,6 +54,7 @@ struct __rte_cache_aligned pkt_rx_queue {
 	struct rte_mempool *mb_pool;
 	uint16_t in_port;
 	uint8_t vlan_strip;
+	uint8_t timestamp_offloading;
 
 	volatile unsigned long rx_pkts;
 	volatile unsigned long rx_bytes;
@@ -82,6 +86,7 @@ struct pmd_internals {
 	struct pkt_rx_queue *rx_queue;
 	struct pkt_tx_queue *tx_queue;
 	uint8_t vlan_strip;
+	uint8_t timestamp_offloading;
 };
 
 static const char *valid_arguments[] = {
@@ -157,6 +162,16 @@ eth_af_packet_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 				PMD_LOG(ERR, "Failed to reinsert VLAN tag");
 		}
 
+		/* add kernel provided timestamp when offloading is enabled */
+		if (pkt_q->timestamp_offloading) {
+			/* since TPACKET_V2 timestamps are provided in nanoseconds resolution */
+			*RTE_MBUF_DYNFIELD(mbuf, timestamp_dynfield_offset,
+				rte_mbuf_timestamp_t *) =
+					(uint64_t)ppd->tp_sec * 1000000000 + ppd->tp_nsec;
+
+			mbuf->ol_flags |= timestamp_dynflag;
+		}
+
 		/* release incoming frame and advance ring buffer */
 		ppd->tp_status = TP_STATUS_KERNEL;
 		if (++framenum >= framecount)
@@ -317,6 +332,16 @@ eth_dev_start(struct rte_eth_dev *dev)
 	struct pmd_internals *internals = dev->data->dev_private;
 	uint16_t i;
 
+	if (internals->timestamp_offloading) {
+		/* Register mbuf field and flag for Rx timestamp */
+		int rc = rte_mbuf_dyn_rx_timestamp_register(&timestamp_dynfield_offset,
+				&timestamp_dynflag);
+		if (rc) {
+			PMD_LOG(ERR, "Cannot register mbuf field/flag for timestamp");
+			return rc;
+		}
+	}
+
 	dev->data->dev_link.link_status = RTE_ETH_LINK_UP;
 	for (i = 0; i < internals->nb_queues; i++) {
 		dev->data->rx_queue_state[i] = RTE_ETH_QUEUE_STATE_STARTED;
@@ -365,6 +390,7 @@ eth_dev_configure(struct rte_eth_dev *dev __rte_unused)
 	struct pmd_internals *internals = dev->data->dev_private;
 
 	internals->vlan_strip = !!(rxmode->offloads & RTE_ETH_RX_OFFLOAD_VLAN_STRIP);
+	internals->timestamp_offloading = !!(rxmode->offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP);
 	return 0;
 }
 
@@ -381,7 +407,8 @@ eth_dev_info(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 	dev_info->min_rx_bufsize = 0;
 	dev_info->tx_offload_capa = RTE_ETH_TX_OFFLOAD_MULTI_SEGS |
 		RTE_ETH_TX_OFFLOAD_VLAN_INSERT;
-	dev_info->rx_offload_capa = RTE_ETH_RX_OFFLOAD_VLAN_STRIP;
+	dev_info->rx_offload_capa = RTE_ETH_RX_OFFLOAD_VLAN_STRIP |
+		RTE_ETH_RX_OFFLOAD_TIMESTAMP;
 
 	return 0;
 }
@@ -508,6 +535,7 @@ eth_rx_queue_setup(struct rte_eth_dev *dev,
 	dev->data->rx_queues[rx_queue_id] = pkt_q;
 	pkt_q->in_port = dev->data->port_id;
 	pkt_q->vlan_strip = internals->vlan_strip;
+	pkt_q->timestamp_offloading = internals->timestamp_offloading;
 
 	return 0;
 }
-- 
2.34.1