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

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

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/net/packetdrill/tcp_accecn_syn_ack_ace_flags_acked_after_retransmit.pkt
Extension
.pkt
Size
1007 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

// Test that SYN-ACK with ACE flags was Acked
// after 2nd retransmission. In this case,
// since we got the last ACK that supports Accurate
// ECN, we consider this as successful negotiation

`./defaults.sh
sysctl -q net.ipv4.tcp_ecn=3
sysctl -q net.ipv4.tcp_ecn_option=2
`

+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 < [noecn] SEWA 0:0(0) win 32792 <mss 1460,nop,nop,sackOK,nop,wscale 8>
+.002 > [noecn] SW. 0:0(0) ack 1 <mss 1460,ECN e1b 1 ceb 0 e0b 1,nop,nop,nop,sackOK,nop,wscale 8>

// Retransmit SYN-ACK without option
+1~+1.1 > [noecn] SW. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>

// SYN-ACK maybe getting blackholed, disable ECN
+2~+2.2 > [noecn] S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>

// Received an ACK with ACE flags, state should be set to negotiation succeeded
+0.1 < [noecn] W. 1:1(0) ack 1 win 320 <ECN e0b 1 ceb 0 e1b 1,nop>
+.002 accept(3, ..., ...) = 4

Annotation

Implementation Notes