From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/net/ipv4/tcp_dctcp.c | 110 ++++++++++++-------------------------------------------
1 files changed, 24 insertions(+), 86 deletions(-)
diff --git a/kernel/net/ipv4/tcp_dctcp.c b/kernel/net/ipv4/tcp_dctcp.c
index 5205c5a..79f7054 100644
--- a/kernel/net/ipv4/tcp_dctcp.c
+++ b/kernel/net/ipv4/tcp_dctcp.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/* DataCenter TCP (DCTCP) congestion control.
*
* http://simula.stanford.edu/~alizade/Site/DCTCP.html
@@ -33,24 +34,19 @@
* Daniel Borkmann <dborkman@redhat.com>
* Florian Westphal <fw@strlen.de>
* Glenn Judd <glenn.judd@morganstanley.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or (at
- * your option) any later version.
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <net/tcp.h>
#include <linux/inet_diag.h>
+#include "tcp_dctcp.h"
#define DCTCP_MAX_ALPHA 1024U
struct dctcp {
- u32 acked_bytes_ecn;
- u32 acked_bytes_total;
- u32 prior_snd_una;
+ u32 old_delivered;
+ u32 old_delivered_ce;
u32 prior_rcv_nxt;
u32 dctcp_alpha;
u32 next_seq;
@@ -72,8 +68,8 @@
{
ca->next_seq = tp->snd_nxt;
- ca->acked_bytes_ecn = 0;
- ca->acked_bytes_total = 0;
+ ca->old_delivered = tp->delivered;
+ ca->old_delivered_ce = tp->delivered_ce;
}
static void dctcp_init(struct sock *sk)
@@ -85,7 +81,6 @@
sk->sk_state == TCP_CLOSE)) {
struct dctcp *ca = inet_csk_ca(sk);
- ca->prior_snd_una = tp->snd_una;
ca->prior_rcv_nxt = tp->rcv_nxt;
ca->dctcp_alpha = min(dctcp_alpha_on_init, DCTCP_MAX_ALPHA);
@@ -113,89 +108,29 @@
return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->dctcp_alpha) >> 11U), 2U);
}
-/* Minimal DCTP CE state machine:
- *
- * S: 0 <- last pkt was non-CE
- * 1 <- last pkt was CE
- */
-
-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);
-
- 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);
- inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW;
- }
-
- ca->prior_rcv_nxt = tp->rcv_nxt;
- ca->ce_state = 1;
-
- tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
-}
-
-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);
-
- 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);
- inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW;
- }
-
- ca->prior_rcv_nxt = tp->rcv_nxt;
- ca->ce_state = 0;
-
- tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
-}
-
static void dctcp_update_alpha(struct sock *sk, u32 flags)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct dctcp *ca = inet_csk_ca(sk);
- u32 acked_bytes = tp->snd_una - ca->prior_snd_una;
-
- /* If ack did not advance snd_una, count dupack as MSS size.
- * If ack did update window, do not count it at all.
- */
- if (acked_bytes == 0 && !(flags & CA_ACK_WIN_UPDATE))
- acked_bytes = inet_csk(sk)->icsk_ack.rcv_mss;
- if (acked_bytes) {
- ca->acked_bytes_total += acked_bytes;
- ca->prior_snd_una = tp->snd_una;
-
- if (flags & CA_ACK_ECE)
- ca->acked_bytes_ecn += acked_bytes;
- }
/* Expired RTT */
if (!before(tp->snd_una, ca->next_seq)) {
- u64 bytes_ecn = ca->acked_bytes_ecn;
+ u32 delivered_ce = tp->delivered_ce - ca->old_delivered_ce;
u32 alpha = ca->dctcp_alpha;
/* alpha = (1 - g) * alpha + g * F */
alpha -= min_not_zero(alpha, alpha >> dctcp_shift_g);
- if (bytes_ecn) {
- /* If dctcp_shift_g == 1, a 32bit value would overflow
- * after 8 Mbytes.
- */
- bytes_ecn <<= (10 - dctcp_shift_g);
- do_div(bytes_ecn, max(1U, ca->acked_bytes_total));
+ if (delivered_ce) {
+ u32 delivered = tp->delivered - ca->old_delivered;
- alpha = min(alpha + (u32)bytes_ecn, DCTCP_MAX_ALPHA);
+ /* If dctcp_shift_g == 1, a 32bit value would overflow
+ * after 8 M packets.
+ */
+ delivered_ce <<= (10 - dctcp_shift_g);
+ delivered_ce /= max(1U, delivered);
+
+ alpha = min(alpha + delivered_ce, DCTCP_MAX_ALPHA);
}
/* dctcp_alpha can be read from dctcp_get_info() without
* synchro, so we ask compiler to not use dctcp_alpha
@@ -227,12 +162,12 @@
static void dctcp_cwnd_event(struct sock *sk, enum tcp_ca_event ev)
{
+ struct dctcp *ca = inet_csk_ca(sk);
+
switch (ev) {
case CA_EVENT_ECN_IS_CE:
- dctcp_ce_state_0_to_1(sk);
- break;
case CA_EVENT_ECN_NO_CE:
- dctcp_ce_state_1_to_0(sk);
+ dctcp_ece_ack_update(sk, ev, &ca->prior_rcv_nxt, &ca->ce_state);
break;
case CA_EVENT_LOSS:
dctcp_react_to_loss(sk);
@@ -247,6 +182,7 @@
union tcp_cc_info *info)
{
const struct dctcp *ca = inet_csk_ca(sk);
+ const struct tcp_sock *tp = tcp_sk(sk);
/* Fill it also in case of VEGASINFO due to req struct limits.
* We can still correctly retrieve it later.
@@ -258,8 +194,10 @@
info->dctcp.dctcp_enabled = 1;
info->dctcp.dctcp_ce_state = (u16) ca->ce_state;
info->dctcp.dctcp_alpha = ca->dctcp_alpha;
- info->dctcp.dctcp_ab_ecn = ca->acked_bytes_ecn;
- info->dctcp.dctcp_ab_tot = ca->acked_bytes_total;
+ info->dctcp.dctcp_ab_ecn = tp->mss_cache *
+ (tp->delivered_ce - ca->old_delivered_ce);
+ info->dctcp.dctcp_ab_tot = tp->mss_cache *
+ (tp->delivered - ca->old_delivered);
}
*attr = INET_DIAG_DCTCPINFO;
--
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