tools/testing/selftests/net/packetdrill/tcp_tcp_info_tcp-info-rwnd-limited.pkt

Source file repositories/reference/linux-study-clean/tools/testing/selftests/net/packetdrill/tcp_tcp_info_tcp-info-rwnd-limited.pkt

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/net/packetdrill/tcp_tcp_info_tcp-info-rwnd-limited.pkt
Extension
.pkt
Size
1894 bytes
Lines
55
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: tools
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
// Test rwnd limited time in tcp_info for client side.

`./defaults.sh`

// Create a socket and set it to non-blocking.
    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 fcntl(3, F_GETFL) = 0x2 (flags O_RDWR)
   +0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0

   +0 connect(3, ..., ...) = -1 EINPROGRESS (Operation now in progress)
   +0 > S 0:0(0) <mss 1460,sackOK,TS val 100 ecr 0,nop,wscale 8>

// Server advertises 0 receive window.
 +.01 < S. 0:0(0) ack 1 win 0 <mss 1000,nop,nop,sackOK>

   +0 > . 1:1(0) ack 1
   +0 getsockopt(3, SOL_SOCKET, SO_ERROR, [0], [4]) = 0
   +0 fcntl(3, F_SETFL, O_RDWR) = 0   // set back to blocking

// Make sure that initial rwnd limited time is 0.
   +0 %{ assert tcpi_rwnd_limited == 0, tcpi_rwnd_limited }%

// Receive window limited time starts here.
   +0 write(3, ..., 1000) = 1000

// Check that rwnd limited time in tcp_info is around 0.1s.
  +.1 %{ assert 98000 <= tcpi_rwnd_limited <= 110000, tcpi_rwnd_limited }%

// Server opens the receive window.
  +.1 < . 1:1(0) ack 1 win 2000

// Check that rwnd limited time in tcp_info is around 0.2s.
   +0 %{ assert 198000 <= tcpi_rwnd_limited <= 210000, tcpi_rwnd_limited }%

   +0 > P. 1:1001(1000) ack 1

// Server advertises a very small receive window.
 +.03 < . 1:1(0) ack 1001 win 10

// Receive window limited time starts again.
   +0 write(3, ..., 1000) = 1000

// Server opens the receive window again.
  +.1 < . 1:1(0) ack 1001 win 2000
// Check that rwnd limited time in tcp_info is around 0.3s
// and busy time is 0.3 + 0.03 (server opened small window temporarily).
   +0 %{ assert 298000 <= tcpi_rwnd_limited <= 310000, tcpi_rwnd_limited;\
         assert 328000 <= tcpi_busy_time <= 340000, tcpi_busy_time;\
}%

   +0 > P. 1001:2001(1000) ack 1
 +.02 < . 1:1(0) ack 2001 win 2000
   +0 %{ assert 348000 <= tcpi_busy_time <= 360000, tcpi_busy_time }%

Annotation

Implementation Notes