1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0
3
4# for debugging set net.netfilter.nf_log_all_netns=1 in init_net
5# or do not use net namespaces.
6modprobe -q nf_conntrack
7sysctl -q net.netfilter.nf_conntrack_log_invalid=6
8
9# Flush old cached data (fastopen cookies).
10ip tcp_metrics flush all > /dev/null 2>&1
11
12# TCP min, default, and max receive and send buffer sizes.
13sysctl -q net.ipv4.tcp_rmem="4096 540000 $((15*1024*1024))"
14sysctl -q net.ipv4.tcp_wmem="4096 $((256*1024)) 4194304"
15
16# TCP congestion control.
17sysctl -q net.ipv4.tcp_congestion_control=cubic
18
19# TCP slow start after idle.
20sysctl -q net.ipv4.tcp_slow_start_after_idle=0
21
22# TCP Explicit Congestion Notification (ECN)
23sysctl -q net.ipv4.tcp_ecn=0
24
25sysctl -q net.ipv4.tcp_notsent_lowat=4294967295 > /dev/null 2>&1
26
27# Override the default qdisc on the tun device.
28# Many tests fail with timing errors if the default
29# is FQ and that paces their flows.
30tc qdisc add dev tun0 root pfifo
31
32# Enable conntrack
33$xtables -A INPUT -m conntrack --ctstate NEW -p tcp --syn
34