Subject: [PATCH net-next v2 10/12] net-timestamp: make bpf for tx timestamp work

From: Jason Xing <[email-masked]>
Date: Sat, 12 Oct 2024 12:06:49 +0800

From: Jason Xing <[email-masked]>

It's time to let bpf extension feature work. I extracted the part
of logic from tcp_tx_timestamp() for bpf extension use, like
TX timestamp flags.

Signed-off-by: Jason Xing <[email-masked]>
---
 net/ipv4/tcp.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 6c8968eb4427..d37e231b2737 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -477,11 +477,31 @@ void tcp_init_sock(struct sock *sk)
 }
 EXPORT_SYMBOL(tcp_init_sock);
 
+static void bpf_tx_timestamp(struct sock *sk, struct sk_buff *skb)
+{
+	u32 tsflags = READ_ONCE(sk->sk_tsflags[BPFPROG_TS_REQUESTOR]);
+
+	if (tsflags && skb) {
+		struct skb_shared_info *shinfo = skb_shinfo(skb);
+		struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+
+		__sock_tx_timestamp(tsflags, &shinfo->tx_flags);
+
+		if (tsflags & SOF_TIMESTAMPING_TX_ACK)
+			tcb->txstamp_ack = 1;
+		if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
+			shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
+	}
+}
+
 static void tcp_tx_timestamp(struct sock *sk, struct sockcm_cookie *sockc)
 {
 	struct sk_buff *skb = tcp_write_queue_tail(sk);
 	u32 tsflags = sockc->tsflags;
 
+	if (static_branch_unlikely(&bpf_tstamp_control))
+		bpf_tx_timestamp(sk, skb);
+
 	if (tsflags && skb) {
 		struct skb_shared_info *shinfo = skb_shinfo(skb);
 		struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
-- 
2.37.3