1 // SPDX-License-Identifier: GPL-2.0
2 // Test of slow start when not application-limited, so that
3 // the cwnd continues to grow.
4 // In this variant, the receiver sends one ACK per 4 packets.
5
6 // Set up config. To keep things simple, disable the
7 // mechanism that defers sending in order to send bigger TSO packets.
8 `./defaults.sh
9 sysctl -q net.ipv4.tcp_tso_win_divisor=100`
10
11 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
12 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
13 +0 bind(3, ..., ...) = 0
14 +0 listen(3, 1) = 0
15
16 +.1 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7>
17 +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>
18 +.1 < . 1:1(0) ack 1 win 257
19 +0 accept(3, ..., ...) = 4
20 +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0
21
22 +0 write(4, ..., 30000) = 30000
23 +0 > P. 1:10001(10000) ack 1
24 +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }%
25
26 +.11 < . 1:1(0) ack 4001 win 257
27 +0 > P. 10001:18001(8000) ack 1
28
29 +.01 < . 1:1(0) ack 8001 win 257
30 +0 > P. 18001:26001(8000) ack 1
31
32 +.005 < . 1:1(0) ack 10001 win 257
33 +0 > P. 26001:30001(4000) ack 1
34
35 +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }%
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