Subject: [PATCH net-next v2 08/12] net-timestamp: introduce TS_ACK_OPT_CB to generate tcp acked timestamp

From: Jason Xing <[email-masked]>
Date: Sat, 12 Oct 2024 12:06:47 +0800

From: Jason Xing <[email-masked]>

When the last sent skb in each sendmsg() is acknowledged in TCP layer,
we can print timestamp by setting BPF_SOCK_OPS_TS_ACK_OPT_CB in
bpf program.

Signed-off-by: Jason Xing <[email-masked]>
---
 include/uapi/linux/bpf.h       | 5 +++++
 net/core/skbuff.c              | 3 +++
 tools/include/uapi/linux/bpf.h | 5 +++++
 3 files changed, 13 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0d00539f247a..1b478ec18ac2 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -7029,6 +7029,11 @@ enum {
 					 * feature is on. It indicates the
 					 * recorded timestamp.
 					 */
+	BPF_SOCK_OPS_TS_ACK_OPT_CB,	/* Called when all the skbs are
+					 * acknowledged 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 832d53de9874..e18305b03a01 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5644,6 +5644,9 @@ static void bpf_skb_tstamp_tx_output(struct sock *sk, int tstype,
 		case SCM_TSTAMP_SND:
 			cb_flag = BPF_SOCK_OPS_TS_SW_OPT_CB;
 			break;
+		case SCM_TSTAMP_ACK:
+			cb_flag = BPF_SOCK_OPS_TS_ACK_OPT_CB;
+			break;
 		default:
 			return;
 		}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 020ec14ffae6..fc9b94de19f2 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -7028,6 +7028,11 @@ enum {
 					 * feature is on. It indicates the
 					 * recorded timestamp.
 					 */
+	BPF_SOCK_OPS_TS_ACK_OPT_CB,	/* Called when all the skbs are
+					 * acknowledged 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
-- 
2.37.3