[PATCH v4 net-next 12/14] tcp: Pass flags to __tcp_send_ack

[chia-yu.chang@xxxxxxxxxxxxxxxxxxx]

From: Ilpo Järvinen <ij@xxxxxxxxxx>

Accurate ECN needs to send custom flags to handle IP-ECN
field reflection during handshake.

Signed-off-by: Ilpo Järvinen <ij@xxxxxxxxxx>
Signed-off-by: Chia-Yu Chang <chia-yu.chang@xxxxxxxxxxxxxxxxxxx>
---
 include/net/tcp.h     | 2 +-
 net/ipv4/bpf_tcp_ca.c | 2 +-
 net/ipv4/tcp_dctcp.h  | 2 +-
 net/ipv4/tcp_output.c | 6 +++---
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index d348ea9be172..81efbe1195fc 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -704,7 +704,7 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority,
 			   enum sk_rst_reason reason);
 int tcp_send_synack(struct sock *);
 void tcp_push_one(struct sock *, unsigned int mss_now);
-void __tcp_send_ack(struct sock *sk, u32 rcv_nxt);
+void __tcp_send_ack(struct sock *sk, u32 rcv_nxt, u16 flags);
 void tcp_send_ack(struct sock *sk);
 void tcp_send_delayed_ack(struct sock *sk);
 void tcp_send_loss_probe(struct sock *sk);
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 554804774628..e01492234b0b 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -121,7 +121,7 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log,
 BPF_CALL_2(bpf_tcp_send_ack, struct tcp_sock *, tp, u32, rcv_nxt)
 {
 	/* bpf_tcp_ca prog cannot have NULL tp */
-	__tcp_send_ack((struct sock *)tp, rcv_nxt);
+	__tcp_send_ack((struct sock *)tp, rcv_nxt, 0);
 	return 0;
 }
 
diff --git a/net/ipv4/tcp_dctcp.h b/net/ipv4/tcp_dctcp.h
index d69a77cbd0c7..4b0259111d81 100644
--- a/net/ipv4/tcp_dctcp.h
+++ b/net/ipv4/tcp_dctcp.h
@@ -28,7 +28,7 @@ static inline void dctcp_ece_ack_update(struct sock *sk, enum tcp_ca_event evt,
 		 */
 		if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) {
 			dctcp_ece_ack_cwr(sk, *ce_state);
-			__tcp_send_ack(sk, *prior_rcv_nxt);
+			__tcp_send_ack(sk, *prior_rcv_nxt, 0);
 		}
 		inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW;
 	}
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index bb83ad43a4e2..556c2da2bc77 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -4232,7 +4232,7 @@ void tcp_send_delayed_ack(struct sock *sk)
 }
 
 /* This routine sends an ack and also updates the window. */
-void __tcp_send_ack(struct sock *sk, u32 rcv_nxt)
+void __tcp_send_ack(struct sock *sk, u32 rcv_nxt, u16 flags)
 {
 	struct sk_buff *buff;
 
@@ -4261,7 +4261,7 @@ void __tcp_send_ack(struct sock *sk, u32 rcv_nxt)
 
 	/* Reserve space for headers and prepare control bits. */
 	skb_reserve(buff, MAX_TCP_HEADER);
-	tcp_init_nondata_skb(buff, tcp_acceptable_seq(sk), TCPHDR_ACK);
+	tcp_init_nondata_skb(buff, tcp_acceptable_seq(sk), TCPHDR_ACK | flags);
 
 	/* We do not want pure acks influencing TCP Small Queues or fq/pacing
 	 * too much.
@@ -4276,7 +4276,7 @@ EXPORT_SYMBOL_GPL(__tcp_send_ack);
 
 void tcp_send_ack(struct sock *sk)
 {
-	__tcp_send_ack(sk, tcp_sk(sk)->rcv_nxt);
+	__tcp_send_ack(sk, tcp_sk(sk)->rcv_nxt, 0);
 }
 
 /* This routine sends a packet with an out of date sequence
-- 
2.34.1