NAME

       passt-repair - Helper setting TCP_REPAIR socket options for passt(1)

SYNOPSIS

       passt-repair PATH

DESCRIPTION

       passt-repair  is  a  privileged  helper  setting  and  clearing  repair  mode on TCP sockets on behalf of
       passt(1), as instructed via single-byte commands over a UNIX domain socket, specified by PATH.

       It can be used to migrate TCP connections between guests  without  granting  additional  capabilities  to
       passt(1)   itself:  to  migrate  TCP  connections,  passt(1)  leverages  repair  mode,  which  needs  the
       CAP_NET_ADMIN capability (see capabilities(7)) to be set or cleared.

PROTOCOL

       passt-repair(1) connects to passt(1) using the socket specified  via  --repair-path  option  in  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), 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)) ancillary message, sent by the server, passt(1).

       The  client,  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

       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

       Stefano Brivio <sbrivio@redhat.com>.

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 (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

       passt(1), qemu(1), capabilities(7), unix(7).

                                                                                                 passt-repair(1)