1// SPDX-License-Identifier: GPL-2.0 2// Test for blocking write. 3--tolerance_usecs=10000 4 5`./defaults.sh 6./set_sysctls.py /proc/sys/net/ipv4/tcp_min_tso_segs=10 7` 8 9// Establish a connection. 10 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 11 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 12 +0 bind(3, ..., ...) = 0 13 +0 listen(3, 1) = 0 14 15 +.1 < S 0:0(0) win 50000 <mss 1000,nop,wscale 0> 16 +0 > S. 0:0(0) ack 1 <mss 1460,nop,wscale 8> 17 +.1 < . 1:1(0) ack 1 win 50000 18 +0 accept(3, ..., ...) = 4 19 20// Kernel doubles our value -> sk->sk_sndbuf is set to 42000 21 +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [21000], 4) = 0 22 +0 getsockopt(4, SOL_SOCKET, SO_SNDBUF, [42000], [4]) = 0 23 24// A write of 60000 does not block. 25 +0...0.300 write(4, ..., 61000) = 61000 // this write() blocks 26 27 +.1 < . 1:1(0) ack 10001 win 50000 28 29 +.1 < . 1:1(0) ack 30001 win 50000 30 31// This ACK should wakeup the write(). An ACK of 35001 does not. 32 +.1 < . 1:1(0) ack 36001 win 50000 33 34// Reset to sysctls defaults. 35`/tmp/sysctl_restore_${PPID}.sh` 36