[PATCH net-next v4 05/11] net-timestamp: support SCM_TSTAMP_SND for bpf extension

[Jason Xing <kerneljasonxing@gmail.com>]

From: Jason Xing <kernelxing@tencent.com>

Support SCM_TSTAMP_SND case. Then we will get the timestamp
when the driver is about to send the skb.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 include/uapi/linux/bpf.h       |  5 +++++
 net/core/skbuff.c              | 13 ++++++++++---
 tools/include/uapi/linux/bpf.h |  5 +++++
 3 files changed, 20 insertions(+), 3 deletions(-)

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 fd4f06b88a2e..73b15d6277f7 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5550,6 +5550,9 @@ static void __skb_tstamp_tx_bpf(struct sock *sk, struct sk_buff *skb, 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;
 	}
@@ -5624,7 +5627,8 @@ static bool skb_tstamp_is_set(const struct sk_buff *skb, int tstype, bool bpf_mo
 			return true;
 		return false;
 	case SCM_TSTAMP_SND:
-		if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP))
+		flag = bpf_mode ? SKBTX_BPF : SKBTX_SW_TSTAMP;
+		if (unlikely(skb_shinfo(skb)->tx_flags & flag))
 			return true;
 		return false;
 	case SCM_TSTAMP_ACK:
@@ -5651,8 +5655,11 @@ EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
 void skb_tstamp_tx(struct sk_buff *orig_skb,
 		   struct skb_shared_hwtstamps *hwtstamps)
 {
-	return skb_tstamp_tx_output(orig_skb, NULL, hwtstamps, orig_skb->sk,
-				    SCM_TSTAMP_SND);
+	int tstype = SCM_TSTAMP_SND;
+
+	skb_tstamp_tx_output(orig_skb, NULL, hwtstamps, orig_skb->sk, tstype);
+	if (unlikely(skb_tstamp_is_set(orig_skb, tstype, true)))
+		__skb_tstamp_tx_bpf(orig_skb->sk, orig_skb, tstype);
 }
 EXPORT_SYMBOL_GPL(skb_tstamp_tx);
 
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
-- 
2.37.3