tools/testing/selftests/net/packetdrill/tcp_ts_recent_invalid_ack.pkt

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

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/net/packetdrill/tcp_ts_recent_invalid_ack.pkt
Extension
.pkt
Size
1014 bytes
Lines
28
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 that we reject TS val updates on a packet with invalid ACK sequence

`./defaults.sh
`

// Create a socket.
    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

// Establish a connection.
  +.1 < S 0:0(0) win 20000 <mss 1000,sackOK,TS val 100 ecr 0>
   +0 > S. 0:0(0) ack 1 <mss 1460,sackOK,TS val 100 ecr 100>
  +.1 < . 1:1(0) ack 1 win 20000 <nop,nop,TS val 200 ecr 100>
   +0 accept(3, ..., ...) = 4

// bad packet with high tsval (its ACK sequence is above our sndnxt)
   +0 < F. 1:1(0) ack 9999 win 20000 <nop,nop,TS val 200000 ecr 100>
// Challenge ACK for SEG.ACK > SND.NXT (RFC 5961 5.2 / RFC 793 3.9).
// ecr=200 (not 200000) proves ts_recent was not updated from the bad packet.
   +0 > . 1:1(0) ack 1 <nop,nop,TS val 200 ecr 200>

   +0 < . 1:1001(1000) ack 1 win 20000 <nop,nop,TS val 201 ecr 100>
   +0 > . 1:1(0) ack 1001 <nop,nop,TS val 200 ecr 201>

Annotation

Implementation Notes