tools/testing/selftests/net/packetdrill/tcp_user_timeout_user-timeout-probe.pkt

Source file repositories/reference/linux-study-clean/tools/testing/selftests/net/packetdrill/tcp_user_timeout_user-timeout-probe.pkt

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/net/packetdrill/tcp_user_timeout_user-timeout-probe.pkt
Extension
.pkt
Size
1230 bytes
Lines
40
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

`./defaults.sh`

    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0


   +0 < S 0:0(0) win 0 <mss 1460>
   +0 > S. 0:0(0) ack 1 <mss 1460>

  +.1 < . 1:1(0) ack 1 win 65530
   +0 accept(3, ..., ...) = 4

   +0 setsockopt(4, SOL_TCP, TCP_USER_TIMEOUT, [3000], 4) = 0
   +0 write(4, ..., 24) = 24
   +0 > P. 1:25(24) ack 1
   +.1 < . 1:1(0) ack 25 win 65530
   +0 %{ assert tcpi_probes == 0, tcpi_probes; \
         assert tcpi_backoff == 0, tcpi_backoff }%

// install a qdisc dropping all packets
   +0 `tc qdisc delete dev tun0 root 2>/dev/null ; tc qdisc add dev tun0 root pfifo limit 0`

   +0 write(4, ..., 24) = 24
   // When qdisc is congested we retry every 500ms
   // (TCP_RESOURCE_PROBE_INTERVAL) and therefore
   // we retry 6 times before hitting 3s timeout.
   // First verify that the connection is alive:
+3 write(4, ..., 24) = 24

   // Now verify that shortly after that the socket is dead:
+1 write(4, ..., 24) = -1 ETIMEDOUT (Connection timed out)

   +0 %{ assert tcpi_probes == 6, tcpi_probes; \
         assert tcpi_backoff == 0, tcpi_backoff }%
   +0 close(4) = 0

Annotation

Implementation Notes