passt-repair(1) General Commands Manual passt-repair(1)

# [NAME](#NAME)

**passt-repair** - Helper setting TCP\_REPAIR socket options for [**passt**(1)](/man/enterprise-packages/passt/passt.1)

# [SYNOPSIS](#SYNOPSIS)

**passt-repair** *PATH*

# [DESCRIPTION](#DESCRIPTION)

**passt-repair** is a privileged helper setting and clearing repair mode on TCP sockets on behalf of [**passt**(1)](/man/enterprise-packages/passt/passt.1), as instructed via single-byte commands over a UNIX domain socket.

It can be used to migrate TCP connections between guests without granting additional capabilities to [**passt**(1)](/man/enterprise-packages/passt/passt.1) itself: to migrate TCP connections, [**passt**(1)](/man/enterprise-packages/passt/passt.1) leverages repair mode, which needs the **CAP\_NET\_ADMIN** capability (see [**capabilities**(7)](/man/enterprise-packages/passt/capabilities.7)) to be set or cleared.

If *PATH* represents a UNIX domain socket, [**passt-repair**(1)](/man/enterprise-packages/passt/passt-repair.1) attempts to connect to it. If it is a directory, [**passt-repair**(1)](/man/enterprise-packages/passt/passt-repair.1) waits until a file ending with *.repair* appears in it, and then attempts to connect to it.

# [PROTOCOL](#PROTOCOL)

[**passt-repair**(1)](/man/enterprise-packages/passt/passt-repair.1) connects to [**passt**(1)](/man/enterprise-packages/passt/passt.1) using the socket specified via *--repair-path* option in [**passt**(1)](/man/enterprise-packages/passt/passt.1) itself. By default, the name is the same as the UNIX domain socket used for guest communication, suffixed by *.repair*.

The messages consist of one 8-bit signed integer that can be [*TCP\_REPAIR\_ON*(1)](/man/enterprise-packages/passt/TCP_REPAIR_ON.1), *TCP\_REPAIR\_OFF* (0), or *TCP\_REPAIR\_OFF\_NO\_WP* (-1), as defined by the Linux kernel user API, and one to SCM\_MAX\_FD (253) sockets as SCM\_RIGHTS (see [**unix**(7)](/man/enterprise-packages/passt/unix.7)) ancillary message, sent by the server, [**passt**(1)](/man/enterprise-packages/passt/passt.1).

The client, [**passt-repair**(1)](/man/enterprise-packages/passt/passt-repair.1), replies with the same byte (and no ancillary message) to indicate success, and closes the connection on failure.

The server closes the connection on error or completion.

# [NOTES](#NOTES)

[**passt-repair**(1)](/man/enterprise-packages/passt/passt-repair.1) can be granted the **CAP\_NET\_ADMIN** capability (preferred, as it limits privileges to the strictly necessary ones), or it can be run as root.

# [AUTHOR](#AUTHOR)

Stefano Brivio <sbrivio@redhat.com>.

# [REPORTING BUGS](#REPORTING_BUGS)

Please report issues on the bug tracker at https://bugs.passt.top/, or send a message to the passt-user@passt.top mailing list, see https://lists.passt.top/.

# [COPYRIGHT](#COPYRIGHT)

Copyright (c) 2025 Red Hat GmbH.

**passt-repair** is free software: you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version.

# [SEE ALSO](#SEE_ALSO)

[**passt**(1)](/man/enterprise-packages/passt/passt.1), [**qemu**(1)](/man/enterprise-packages/passt/qemu.1), [**capabilities**(7)](/man/enterprise-packages/passt/capabilities.7), [**unix**(7)](/man/enterprise-packages/passt/unix.7).

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Document: passt-repair(1) from passt 2026.10.02-r2 (Chainguard OS)
Source: https://passt.top/passt