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-rw-r--r--include/net/tcp.h1
-rw-r--r--net/ipv4/tcp_dctcp.c34
-rw-r--r--net/ipv4/tcp_output.c11
3 files changed, 13 insertions, 33 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 15564a2cc28c..521490fd8928 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -530,6 +530,7 @@ int tcp_send_synack(struct sock *);
bool tcp_syn_flood_action(struct sock *sk, const struct sk_buff *skb,
const char *proto);
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);
void tcp_send_delayed_ack(struct sock *sk);
void tcp_send_loss_probe(struct sock *sk);
diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c
index 33e74cb51b89..faab1c0e4c26 100644
--- a/net/ipv4/tcp_dctcp.c
+++ b/net/ipv4/tcp_dctcp.c
@@ -132,21 +132,8 @@ static void dctcp_ce_state_0_to_1(struct sock *sk)
* ACK has not sent yet.
*/
if (!ca->ce_state &&
- inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) {
- u32 tmp_rcv_nxt;
-
- /* Save current rcv_nxt. */
- tmp_rcv_nxt = tp->rcv_nxt;
-
- /* Generate previous ack with CE=0. */
- tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
- tp->rcv_nxt = ca->prior_rcv_nxt;
-
- tcp_send_ack(sk);
-
- /* Recover current rcv_nxt. */
- tp->rcv_nxt = tmp_rcv_nxt;
- }
+ inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER)
+ __tcp_send_ack(sk, ca->prior_rcv_nxt);
ca->prior_rcv_nxt = tp->rcv_nxt;
ca->ce_state = 1;
@@ -163,21 +150,8 @@ static void dctcp_ce_state_1_to_0(struct sock *sk)
* ACK has not sent yet.
*/
if (ca->ce_state &&
- inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) {
- u32 tmp_rcv_nxt;
-
- /* Save current rcv_nxt. */
- tmp_rcv_nxt = tp->rcv_nxt;
-
- /* Generate previous ack with CE=1. */
- tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
- tp->rcv_nxt = ca->prior_rcv_nxt;
-
- tcp_send_ack(sk);
-
- /* Recover current rcv_nxt. */
- tp->rcv_nxt = tmp_rcv_nxt;
- }
+ inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER)
+ __tcp_send_ack(sk, ca->prior_rcv_nxt);
ca->prior_rcv_nxt = tp->rcv_nxt;
ca->ce_state = 0;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 371ea9e76bd1..a3c701e079fd 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -183,8 +183,13 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
}
/* Account for an ACK we sent. */
-static inline void tcp_event_ack_sent(struct sock *sk, unsigned int pkts)
+static inline void tcp_event_ack_sent(struct sock *sk, unsigned int pkts,
+ u32 rcv_nxt)
{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (unlikely(rcv_nxt != tp->rcv_nxt))
+ return; /* Special ACK sent by DCTCP to reflect ECN */
tcp_dec_quickack_mode(sk, pkts);
inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
}
@@ -990,7 +995,7 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
icsk->icsk_af_ops->send_check(sk, skb);
if (likely(tcb->tcp_flags & TCPHDR_ACK))
- tcp_event_ack_sent(sk, tcp_skb_pcount(skb));
+ tcp_event_ack_sent(sk, tcp_skb_pcount(skb), rcv_nxt);
if (skb->len != tcp_header_size)
tcp_event_data_sent(tp, sk);
@@ -3258,12 +3263,12 @@ void __tcp_send_ack(struct sock *sk, u32 rcv_nxt)
skb_mstamp_get(&buff->skb_mstamp);
__tcp_transmit_skb(sk, buff, 0, sk_gfp_atomic(sk, GFP_ATOMIC), rcv_nxt);
}
+EXPORT_SYMBOL_GPL(__tcp_send_ack);
void tcp_send_ack(struct sock *sk)
{
__tcp_send_ack(sk, tcp_sk(sk)->rcv_nxt);
}
-EXPORT_SYMBOL_GPL(tcp_send_ack);
/* This routine sends a packet with an out of date sequence
* number. It assumes the other end will try to ack it.