1// SPDX-License-Identifier: GPL-2.0 2// 3// Test SYN+ACK RTX with 1s RTO. 4// 5`./defaults.sh 6 ./set_sysctls.py /proc/sys/net/ipv4/tcp_rto_max_ms=1000` 7 8// 9// Test 1: TFO SYN+ACK 10// 11 0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, 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 +0 setsockopt(3, SOL_TCP, TCP_FASTOPEN, [1], 4) = 0 16 17 +0 < S 0:10(10) win 1000 <mss 1460,sackOK,nop,nop,FO TFO_COOKIE,nop,nop> 18 +0 > S. 0:0(0) ack 11 <mss 1460,nop,nop,sackOK> 19 20// RTO must be capped to 1s 21 +1 > S. 0:0(0) ack 11 <mss 1460,nop,nop,sackOK> 22 +1 > S. 0:0(0) ack 11 <mss 1460,nop,nop,sackOK> 23 +1 > S. 0:0(0) ack 11 <mss 1460,nop,nop,sackOK> 24 25 +0 < . 11:11(0) ack 1 win 1000 <mss 1460,nop,nop,sackOK> 26 +0 accept(3, ..., ...) = 4 27 +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) != 0, tcpi_options }% 28 29 +0 close(4) = 0 30 +0 close(3) = 0 31 32 33// 34// Test 2: non-TFO SYN+ACK 35// 36 +0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3 37 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 38 +0 bind(3, ..., ...) = 0 39 +0 listen(3, 1) = 0 40 41 +0 < S 0:0(0) win 1000 <mss 1460,sackOK,nop,nop> 42 +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK> 43 44// RTO must be capped to 1s 45 +1 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK> 46 +1 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK> 47 +1 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK> 48 49 +0 < . 1:1(0) ack 1 win 1000 <mss 1460,nop,nop,sackOK> 50 +0 accept(3, ..., ...) = 4 51 +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) == 0, tcpi_options }% 52 53 +0 close(4) = 0 54 +0 close(3) = 0 55