1 #!/bin/bash
2 # SPDX-License-Identifier: GPL-2.0
3 #
4 # Set standard production config values that relate to TCP behavior.
5
6 # Flush old cached data (fastopen cookies).
7 ip tcp_metrics flush all > /dev/null 2>&1
8
9 # TCP min, default, and max receive and send buffer sizes.
10 sysctl -q net.ipv4.tcp_rmem="4096 540000 $((15*1024*1024))"
11 sysctl -q net.ipv4.tcp_wmem="4096 $((256*1024)) 4194304"
12
13 # TCP timestamps.
14 sysctl -q net.ipv4.tcp_timestamps=1
15
16 # TCP SYN(ACK) retry thresholds
17 sysctl -q net.ipv4.tcp_syn_retries=5
18 sysctl -q net.ipv4.tcp_synack_retries=5
19
20 # TCP Forward RTO-Recovery, RFC 5682.
21 sysctl -q net.ipv4.tcp_frto=2
22
23 # TCP Selective Acknowledgements (SACK)
24 sysctl -q net.ipv4.tcp_sack=1
25
26 # TCP Duplicate Selective Acknowledgements (DSACK)
27 sysctl -q net.ipv4.tcp_dsack=1
28
29 # TCP FACK (Forward Acknowldgement)
30 sysctl -q net.ipv4.tcp_fack=0
31
32 # TCP reordering degree ("dupthresh" threshold for entering Fast Recovery).
33 sysctl -q net.ipv4.tcp_reordering=3
34
35 # TCP congestion control.
36 sysctl -q net.ipv4.tcp_congestion_control=cubic
37
38 # TCP slow start after idle.
39 sysctl -q net.ipv4.tcp_slow_start_after_idle=0
40
41 # TCP RACK and TLP.
42 sysctl -q net.ipv4.tcp_early_retrans=4 net.ipv4.tcp_recovery=1
43
44 # TCP method for deciding when to defer sending to accumulate big TSO packets.
45 sysctl -q net.ipv4.tcp_tso_win_divisor=3
46
47 # TCP Explicit Congestion Notification (ECN)
48 sysctl -q net.ipv4.tcp_ecn=0
49
50 sysctl -q net.ipv4.tcp_pacing_ss_ratio=200
51 sysctl -q net.ipv4.tcp_pacing_ca_ratio=120
52 sysctl -q net.ipv4.tcp_notsent_lowat=4294967295 > /dev/null 2>&1
53
54 sysctl -q net.ipv4.tcp_fastopen=0x70403
55 sysctl -q net.ipv4.tcp_fastopen_key=a1a1a1a1-b2b2b2b2-c3c3c3c3-d4d4d4d4
56
57 sysctl -q net.ipv4.tcp_syncookies=1
58
59 # Override the default qdisc on the tun device.
60 # Many tests fail with timing errors if the default
61 # is FQ and that paces their flows.
62 tc qdisc add dev tun0 root pfifo
63
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