Subject: [PATCH net-next v5 08/15] net-timestamp: support sw SCM_TSTAMP_SND for bpf extension

From: Jason Xing <[email-masked]>
Date: Sun, 12 Jan 2025 19:37:41 +0800

Support SCM_TSTAMP_SND case. Then we will get the software
timestamp when the driver is about to send the skb. Later, I
will support the hardware timestamp.

Signed-off-by: Jason Xing <[email-masked]>
---
 include/linux/skbuff.h         | 2 +-
 include/uapi/linux/bpf.h       | 5 +++++
 net/core/skbuff.c              | 3 +++
 tools/include/uapi/linux/bpf.h | 5 +++++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 30901dfb4539..4f38c17c67a7 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4578,7 +4578,7 @@ void skb_sw_tstamp_tx(struct sk_buff *orig_skb);
 static inline void skb_tx_timestamp(struct sk_buff *skb)
 {
 	skb_clone_tx_timestamp(skb);
-	if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP)
+	if (skb_shinfo(skb)->tx_flags & (SKBTX_SW_TSTAMP | SKBTX_BPF))
 		skb_sw_tstamp_tx(skb);
 }
 
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 72f93c6e45c1..a6d761f07f67 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -7027,6 +7027,11 @@ enum {
 					 * feature is on. It indicates the
 					 * recorded timestamp.
 					 */
+	BPF_SOCK_OPS_TS_SW_OPT_CB,	/* Called when skb is about to send
+					 * to the nic when SO_TIMESTAMPING
+					 * feature is on. It indicates the
+					 * recorded timestamp.
+					 */
 };
 
 /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 169c6d03d698..0fb31df4ed95 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5578,6 +5578,9 @@ static void __skb_tstamp_tx_bpf(struct sk_buff *skb, struct sock *sk, int tstype
 	case SCM_TSTAMP_SCHED:
 		op = BPF_SOCK_OPS_TS_SCHED_OPT_CB;
 		break;
+	case SCM_TSTAMP_SND:
+		op = BPF_SOCK_OPS_TS_SW_OPT_CB;
+		break;
 	default:
 		return;
 	}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 891217ab6d2d..73fc0a95c9ca 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -7020,6 +7020,11 @@ enum {
 					 * feature is on. It indicates the
 					 * recorded timestamp.
 					 */
+	BPF_SOCK_OPS_TS_SW_OPT_CB,	/* Called when skb is about to send
+					 * to the nic when SO_TIMESTAMPING
+					 * feature is on. It indicates the
+					 * recorded timestamp.
+					 */
 };
 
 /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
-- 
2.43.5