xref: /linux/tools/testing/selftests/net/packetdrill/tcp_blocking_blocking-write.pkt (revision 0ad9617c78acbc71373fb341a6f75d4012b01d69)
1*6f669205SSoham Chakradeo// SPDX-License-Identifier: GPL-2.0
2*6f669205SSoham Chakradeo// Test for blocking write.
3*6f669205SSoham Chakradeo--tolerance_usecs=10000
4*6f669205SSoham Chakradeo
5*6f669205SSoham Chakradeo`./defaults.sh
6*6f669205SSoham Chakradeo./set_sysctls.py /proc/sys/net/ipv4/tcp_min_tso_segs=10
7*6f669205SSoham Chakradeo`
8*6f669205SSoham Chakradeo
9*6f669205SSoham Chakradeo// Establish a connection.
10*6f669205SSoham Chakradeo    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
11*6f669205SSoham Chakradeo   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
12*6f669205SSoham Chakradeo   +0 bind(3, ..., ...) = 0
13*6f669205SSoham Chakradeo   +0 listen(3, 1) = 0
14*6f669205SSoham Chakradeo
15*6f669205SSoham Chakradeo  +.1 < S 0:0(0) win 50000 <mss 1000,nop,wscale 0>
16*6f669205SSoham Chakradeo   +0 > S. 0:0(0) ack 1 <mss 1460,nop,wscale 8>
17*6f669205SSoham Chakradeo  +.1 < . 1:1(0) ack 1 win 50000
18*6f669205SSoham Chakradeo   +0 accept(3, ..., ...) = 4
19*6f669205SSoham Chakradeo
20*6f669205SSoham Chakradeo// Kernel doubles our value -> sk->sk_sndbuf is set to 42000
21*6f669205SSoham Chakradeo   +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF,  [21000], 4) = 0
22*6f669205SSoham Chakradeo   +0 getsockopt(4, SOL_SOCKET, SO_SNDBUF,  [42000], [4]) = 0
23*6f669205SSoham Chakradeo
24*6f669205SSoham Chakradeo// A write of 60000 does not block.
25*6f669205SSoham Chakradeo   +0...0.300 write(4, ..., 61000) = 61000    // this write() blocks
26*6f669205SSoham Chakradeo
27*6f669205SSoham Chakradeo  +.1 < . 1:1(0) ack 10001 win 50000
28*6f669205SSoham Chakradeo
29*6f669205SSoham Chakradeo  +.1 < . 1:1(0) ack 30001 win 50000
30*6f669205SSoham Chakradeo
31*6f669205SSoham Chakradeo// This ACK should wakeup the write(). An ACK of 35001 does not.
32*6f669205SSoham Chakradeo  +.1 < . 1:1(0) ack 36001 win 50000
33*6f669205SSoham Chakradeo
34*6f669205SSoham Chakradeo// Reset to sysctls defaults.
35*6f669205SSoham Chakradeo`/tmp/sysctl_restore_${PPID}.sh`
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