// Test against classic ECN server
// Not-ECT on SYN and server sets 1|0|1 (AE is unused for classic ECN)

`./defaults.sh
sysctl -q net.ipv4.tcp_ecn=3
`

    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 4
+.002 ... 0.052 connect(4, ..., ...) = 0

+.002 > [noecn] SEWA 0:0(0) <mss 1460,sackOK,TS val 100 ecr 0,nop,wscale 8>
+0.05 < [noecn] SEA. 0:0(0) ack 1 win 32767 <mss 1460,sackOK,TS val 700 ecr 100,nop,wscale 8>
+.002 > [ect0] W. 1:1(0) ack 1 <nop, nop, TS val 200 ecr 700>

+0 write(4, ..., 100) = 100
+.002 > [ect0] P.5 1:101(100) ack 1 <nop,nop,TS val 300 ecr 700>
+0 close(4) = 0

+.002 > [ect0] F.5 101:101(0) ack 1 <nop,nop,TS val 400 ecr 700>
+0.1 < [noecn] R. 1:1(0) ack 102 win 4242