[PATCH bpf-next v9 05/12] net-timestamp: prepare for isolating two modes of SO_TIMESTAMPING

[Jason Xing <kerneljasonxing@gmail.com>]

No functional changes here, only add test to see if the orig_skb
matches the usage of application SO_TIMESTAMPING. And it's good to
support two modes in parallel later in this series.

Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
---
 net/core/skbuff.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a441613a1e6c..46530d516909 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5539,18 +5539,37 @@ void skb_complete_tx_timestamp(struct sk_buff *skb,
 }
 EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
 
+static bool skb_tstamp_tx_report_so_timestamping(struct sk_buff *skb,
+						 int tstype, bool sw)
+{
+	switch (tstype) {
+	case SCM_TSTAMP_SCHED:
+		return skb_shinfo(skb)->tx_flags & SKBTX_SCHED_TSTAMP;
+	case SCM_TSTAMP_SND:
+		return skb_shinfo(skb)->tx_flags & (sw ? SKBTX_SW_TSTAMP :
+						    SKBTX_HW_TSTAMP);
+	case SCM_TSTAMP_ACK:
+		return TCP_SKB_CB(skb)->txstamp_ack;
+	}
+
+	return false;
+}
+
 void __skb_tstamp_tx(struct sk_buff *orig_skb,
 		     const struct sk_buff *ack_skb,
 		     struct skb_shared_hwtstamps *hwtstamps,
 		     struct sock *sk, int tstype)
 {
+	bool tsonly, opt_stats = false, sw = hwtstamps ? false : true;
 	struct sk_buff *skb;
-	bool tsonly, opt_stats = false;
 	u32 tsflags;
 
 	if (!sk)
 		return;
 
+	if (!skb_tstamp_tx_report_so_timestamping(orig_skb, tstype, sw))
+		return;
+
 	tsflags = READ_ONCE(sk->sk_tsflags);
 	if (!hwtstamps && !(tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW) &&
 	    skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS)
-- 
2.43.5