1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
| | <!---
SPDX-License-Identifier: GPL-2.0-or-later
Copyright (c) 2025 Red Hat GmbH
Author: Stefano Brivio <sbrivio@redhat.com>
-->
Migration
=========
These test programs show a migration of a TCP connection from one process to
another using the TCP_REPAIR socket option.
The two processes are a mock of the matching implementation in passt(1), and run
unprivileged, so they rely on the passt-repair helper to connect to them and set
or clear TCP_REPAIR on the connection socket, transferred to the helper using
SCM_RIGHTS.
The passt-repair helper needs to have the CAP_NET_ADMIN capability, or run as
root.
Example of usage
----------------
* Start the test server
$ nc -l 9999
* Start the source side of the TCP client (mock of the source instance of passt)
$ ./source 127.0.0.1 9999 9998 /tmp/repair.sock
* The client sends a test string, and waits for a connection from passt-repair
# passt-repair /tmp/repair.sock
* The socket is now in repair mode, and `source` dumps sequences, then exits
sending sequence: 3244673313
receiving sequence: 2250449386
* Continue the connection on the target side, restarting from those sequences
$ ./target 127.0.0.1 9999 9998 /tmp/repair.sock 3244673313 2250449386
* The target side now waits for a connection from passt-repair
# passt-repair /tmp/repair.sock
* The target side asks passt-repair to switch the socket to repair mode, sets up
the TCP sequences, then asks passt-repair to clear repair mode, and sends a
test string to the server
|