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-rw-r--r--net/ipv4/tcp_dctcp.c52
-rw-r--r--net/ipv4/tcp_input.c3
-rw-r--r--net/ipv4/tcp_output.c32
3 files changed, 42 insertions, 45 deletions
diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c
index 5869f89ca656..8b637f9f23a2 100644
--- a/net/ipv4/tcp_dctcp.c
+++ b/net/ipv4/tcp_dctcp.c
@@ -129,24 +129,14 @@ static void dctcp_ce_state_0_to_1(struct sock *sk)
struct dctcp *ca = inet_csk_ca(sk);
struct tcp_sock *tp = tcp_sk(sk);
- /* State has changed from CE=0 to CE=1 and delayed
- * 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;
+ if (!ca->ce_state) {
+ /* State has changed from CE=0 to CE=1, force an immediate
+ * ACK to reflect the new CE state. If an ACK was delayed,
+ * send that first to reflect the prior CE state.
+ */
+ if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER)
+ __tcp_send_ack(sk, ca->prior_rcv_nxt);
+ tcp_enter_quickack_mode(sk, 1);
}
ca->prior_rcv_nxt = tp->rcv_nxt;
@@ -160,24 +150,14 @@ static void dctcp_ce_state_1_to_0(struct sock *sk)
struct dctcp *ca = inet_csk_ca(sk);
struct tcp_sock *tp = tcp_sk(sk);
- /* State has changed from CE=1 to CE=0 and delayed
- * 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;
+ if (ca->ce_state) {
+ /* State has changed from CE=1 to CE=0, force an immediate
+ * ACK to reflect the new CE state. If an ACK was delayed,
+ * send that first to reflect the prior CE state.
+ */
+ if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER)
+ __tcp_send_ack(sk, ca->prior_rcv_nxt);
+ tcp_enter_quickack_mode(sk, 1);
}
ca->prior_rcv_nxt = tp->rcv_nxt;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 8e5522c6833a..6bade06aaf72 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -215,7 +215,7 @@ static void tcp_incr_quickack(struct sock *sk, unsigned int max_quickacks)
icsk->icsk_ack.quick = quickacks;
}
-static void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks)
+void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks)
{
struct inet_connection_sock *icsk = inet_csk(sk);
@@ -223,6 +223,7 @@ static void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks)
icsk->icsk_ack.pingpong = 0;
icsk->icsk_ack.ato = TCP_ATO_MIN;
}
+EXPORT_SYMBOL(tcp_enter_quickack_mode);
/* Send ACKs quickly, if "quick" count is not exhausted
* and the session is not interactive.
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 00e5a300ddb9..c4172c1fb198 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -160,7 +160,8 @@ 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);
@@ -171,6 +172,9 @@ static inline void tcp_event_ack_sent(struct sock *sk, unsigned int pkts)
if (hrtimer_try_to_cancel(&tp->compressed_ack_timer) == 1)
__sock_put(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);
}
@@ -1023,8 +1027,8 @@ static void tcp_update_skb_after_send(struct tcp_sock *tp, struct sk_buff *skb)
* We are working here with either a clone of the original
* SKB, or a fresh unique copy made by the retransmit engine.
*/
-static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
- gfp_t gfp_mask)
+static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
+ int clone_it, gfp_t gfp_mask, u32 rcv_nxt)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct inet_sock *inet;
@@ -1100,7 +1104,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
th->source = inet->inet_sport;
th->dest = inet->inet_dport;
th->seq = htonl(tcb->seq);
- th->ack_seq = htonl(tp->rcv_nxt);
+ th->ack_seq = htonl(rcv_nxt);
*(((__be16 *)th) + 6) = htons(((tcp_header_size >> 2) << 12) |
tcb->tcp_flags);
@@ -1141,7 +1145,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
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);
@@ -1178,6 +1182,13 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
return err;
}
+static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
+ gfp_t gfp_mask)
+{
+ return __tcp_transmit_skb(sk, skb, clone_it, gfp_mask,
+ tcp_sk(sk)->rcv_nxt);
+}
+
/* This routine just queues the buffer for sending.
*
* NOTE: probe0 timer is not checked, do not forget tcp_push_pending_frames,
@@ -3571,7 +3582,7 @@ 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)
+void __tcp_send_ack(struct sock *sk, u32 rcv_nxt)
{
struct sk_buff *buff;
@@ -3604,9 +3615,14 @@ void tcp_send_ack(struct sock *sk)
skb_set_tcp_pure_ack(buff);
/* Send it off, this clears delayed acks for us. */
- tcp_transmit_skb(sk, buff, 0, (__force gfp_t)0);
+ __tcp_transmit_skb(sk, buff, 0, (__force gfp_t)0, 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.
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 17:05:02 +0000