[PATCH v4 1/5] net: timestamp: add helper returning skb's tx tstamp

[Pavel Begunkov <asml.silence@gmail.com>]

Add a helper function skb_get_tx_timestamp() that returns a tx timestamp
associated with an error queue skb.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 include/net/sock.h |  9 +++++++++
 net/socket.c       | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/include/net/sock.h b/include/net/sock.h
index 92e7c1aae3cc..0b96196d8a34 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2677,6 +2677,15 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
 			     struct sk_buff *skb);
 
+enum {
+	NET_TIMESTAMP_ORIGIN_SW		= 0,
+	NET_TIMESTAMP_ORIGIN_HW		= 1,
+};
+
+bool skb_has_tx_timestamp(struct sk_buff *skb, const struct sock *sk);
+int skb_get_tx_timestamp(struct sk_buff *skb, struct sock *sk,
+			 struct timespec64 *ts);
+
 static inline void
 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
 {
diff --git a/net/socket.c b/net/socket.c
index 9a0e720f0859..eefbd730a9a2 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -843,6 +843,52 @@ static void put_ts_pktinfo(struct msghdr *msg, struct sk_buff *skb,
 		 sizeof(ts_pktinfo), &ts_pktinfo);
 }
 
+bool skb_has_tx_timestamp(struct sk_buff *skb, const struct sock *sk)
+{
+	const struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
+	u32 tsflags = READ_ONCE(sk->sk_tsflags);
+
+	if (serr->ee.ee_errno != ENOMSG ||
+	   serr->ee.ee_origin != SO_EE_ORIGIN_TIMESTAMPING)
+		return false;
+
+	/* software time stamp available and wanted */
+	if ((tsflags & SOF_TIMESTAMPING_SOFTWARE) && skb->tstamp)
+		return true;
+	/* hardware time stamps available and wanted */
+	return (tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
+		skb_hwtstamps(skb)->hwtstamp;
+}
+
+int skb_get_tx_timestamp(struct sk_buff *skb, struct sock *sk,
+			  struct timespec64 *ts)
+{
+	u32 tsflags = READ_ONCE(sk->sk_tsflags);
+	ktime_t hwtstamp;
+	int if_index = 0;
+
+	if ((tsflags & SOF_TIMESTAMPING_SOFTWARE) &&
+	    ktime_to_timespec64_cond(skb->tstamp, ts))
+		return NET_TIMESTAMP_ORIGIN_SW;
+
+	if (!(tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) ||
+	    skb_is_swtx_tstamp(skb, false))
+		return -ENOENT;
+
+	if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP_NETDEV)
+		hwtstamp = get_timestamp(sk, skb, &if_index);
+	else
+		hwtstamp = skb_hwtstamps(skb)->hwtstamp;
+
+	if (tsflags & SOF_TIMESTAMPING_BIND_PHC)
+		hwtstamp = ptp_convert_timestamp(&hwtstamp,
+						READ_ONCE(sk->sk_bind_phc));
+	if (!ktime_to_timespec64_cond(hwtstamp, ts))
+		return -ENOENT;
+
+	return NET_TIMESTAMP_ORIGIN_HW;
+}
+
 /*
  * called from sock_recv_timestamp() if sock_flag(sk, SOCK_RCVTSTAMP)
  */
-- 
2.49.0