1*e874be27SWillem de Bruijn// SPDX-License-Identifier: GPL-2.0
2*e874be27SWillem de Bruijn// Test of slow start when an outstanding flight of packets is
3*e874be27SWillem de Bruijn// less than the current cwnd, and not big enough to bump up cwnd.
4*e874be27SWillem de Bruijn//
5*e874be27SWillem de Bruijn// In this variant, the receiver ACKs every other packet,
6*e874be27SWillem de Bruijn// approximating standard delayed ACKs.
7*e874be27SWillem de Bruijn
8*e874be27SWillem de Bruijn// Set up config.
9*e874be27SWillem de Bruijn`./defaults.sh`
10*e874be27SWillem de Bruijn
11*e874be27SWillem de Bruijn    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
12*e874be27SWillem de Bruijn   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
13*e874be27SWillem de Bruijn   +0 bind(3, ..., ...) = 0
14*e874be27SWillem de Bruijn   +0 listen(3, 1) = 0
15*e874be27SWillem de Bruijn
16*e874be27SWillem de Bruijn   +0 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7>
17*e874be27SWillem de Bruijn   +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>
18*e874be27SWillem de Bruijn   +0 < . 1:1(0) ack 1 win 257
19*e874be27SWillem de Bruijn   +0 accept(3, ..., ...) = 4
20*e874be27SWillem de Bruijn
21*e874be27SWillem de Bruijn// Only send 5 packets.
22*e874be27SWillem de Bruijn   +0 write(4, ..., 5000) = 5000
23*e874be27SWillem de Bruijn   +0 > P. 1:5001(5000) ack 1
24*e874be27SWillem de Bruijn   +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }%
25*e874be27SWillem de Bruijn
26*e874be27SWillem de Bruijn   +0 < . 1:1(0) ack 2001 win 257
27*e874be27SWillem de Bruijn   +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }%
28*e874be27SWillem de Bruijn
29*e874be27SWillem de Bruijn   +0 < . 1:1(0) ack 4001 win 257
30*e874be27SWillem de Bruijn   +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }%
31*e874be27SWillem de Bruijn
32*e874be27SWillem de Bruijn   +0 < . 1:1(0) ack 5001 win 257
33*e874be27SWillem de Bruijn   +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }%
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