1 // SPDX-License-Identifier: GPL-2.0
2 // Test of slow start when an outstanding flight of packets is
3 // less than the current cwnd, and not big enough to bump up cwnd.
4 //
5 // In this variant, the receiver ACKs every other packet,
6 // approximating standard delayed ACKs.
7
8 // Set up config.
9 `./defaults.sh`
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 +0 < 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 +0 < . 1:1(0) ack 1 win 257
19 +0 accept(3, ..., ...) = 4
20
21 // Only send 5 packets.
22 +0 write(4, ..., 5000) = 5000
23 +0 > P. 1:5001(5000) ack 1
24 +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }%
25
26 +0 < . 1:1(0) ack 2001 win 257
27 +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }%
28
29 +0 < . 1:1(0) ack 4001 win 257
30 +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }%
31
32 +0 < . 1:1(0) ack 5001 win 257
33 +0 %{ assert tcpi_snd_cwnd == 10, 'cwnd=%d' % tcpi_snd_cwnd }%
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