tools/testing/selftests/net/packetdrill/tcp_eor_no-coalesce-retrans.pkt

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

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/net/packetdrill/tcp_eor_no-coalesce-retrans.pkt
Extension
.pkt
Size
2668 bytes
Lines
73
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 TCP does not append any data from consequent writes to the tail
// skb created for the chunk. Also, when packets are retransmitted, they
// will not be coalesce into the same skb.
`./defaults.sh
`

// Initialize connection
    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 32792 <mss 1000,sackOK,nop,nop,nop,wscale 10>
   +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>
 +.01 < . 1:1(0) ack 1 win 514

   +0 accept(3, ..., ...) = 4

// Write a 10400B chunk to fill the ICW, and have a 400 byte skb sitting on
// the tail.
   +0 write(4, ..., 10400) = 10400

// Write 10 400B chunks with no coalescing options.
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
   +0 send(4, ..., 400, MSG_EOR) = 400
// This chunk should not be appended to the skbs created for the previous chunk.
   +0 write(4, ..., 10000) = 10000

   +0 > P. 1:10001(10000) ack 1
+.001 < .  1:1(0) ack 10001 win 514
// Now we have enough room to send out the 2 x 400B packets out.
   +0 > P. 10001:10801(800) ack 1
// The 9 remaining 400B chunks should be sent as individual packets.
   +0 > P. 10801:11201(400) ack 1
   +0 > P. 11201:11601(400) ack 1
   +0 > P. 11601:12001(400) ack 1
   +0 > P. 12001:12401(400) ack 1
   +0 > P. 12401:12801(400) ack 1
   +0 > P. 12801:13201(400) ack 1
   +0 > P. 13201:13601(400) ack 1
   +0 > P. 13601:14001(400) ack 1
   +0 > P. 14001:14401(400) ack 1
// The last 10KB chunk should be sent separately.
   +0 > P. 14401:24401(10000) ack 1

+.001 < .  1:1(0) ack 10401 win 514
+.001 < .  1:1(0) ack 10801 win 514
+.001 < .  1:1(0) ack 11201 win 514
+.001 < .  1:1(0) ack 11601 win 514
+.001 < .  1:1(0) ack 12001 win 514 <sack 13201:14401,nop,nop>
// TCP should fill the hole but no coalescing should happen, and all
// retransmissions should be sent out as individual packets.

// Note : This is timeout based retransmit.
// Do not put +0 here or flakes will come back.
+.004~+.008 > P. 12001:12401(400) ack 1

+.001 < .  1:1(0) ack 12401 win 514 <sack 13201:14401,nop,nop>
   +0 > P. 12401:12801(400) ack 1
   +0 > P. 12801:13201(400) ack 1
+.001 < .  1:1(0) ack 12801 win 514 <sack 13201:14401,nop,nop>

Annotation

Implementation Notes