nbd_connect_vsock - connect to NBD server over AF_VSOCK protocol

       Eric Blake

       Richard W.M. Jones

       Copyright Red Hat

       Connect (synchronously) over the "AF_VSOCK" protocol from a virtual machine to an NBD server, usually
       running on the host.  The "cid" and "port" parameters specify the server address.  Usually "cid" should
       be 2 (to connect to the host), and "port" might be 10809 or another port number assigned to you by the
       host administrator.

       Not all systems support "AF_VSOCK"; to determine if libnbd was built on a system with vsock support, see
       nbd_supports_vsock(3).

       This call returns when the connection has been made.  By default, this proceeds all the way to
       transmission phase, but nbd_set_opt_mode(3) can be used for manual control over option negotiation
       performed before transmission phase.

       On error -1 is returned.

       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.

       The following parameters must not be NULL: "h".  For more information see "Non-NULL parameters" in
       libnbd(3).

       nbd_connect_vsock can be called when the handle is in the following state:

        ┌─────────────────────────────────────┬─────────────────────────┐
        │ Handle created, before connecting   │ ✅ allowed              │
        │ Connecting                          │ ❌ error                │
        │ Connecting & handshaking (opt_mode) │ ❌ error                │
        │ Connected to the server             │ ❌ error                │
        │ Connection shut down                │ ❌ error                │
        │ Handle dead                         │ ❌ error                │
        └─────────────────────────────────────┴─────────────────────────┘

       This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser
       General Public License as published by the Free Software Foundation; either version 2 of the License, or
       (at your option) any later version.

       This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
       the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
       Public License for more details.

       You should have received a copy of the GNU Lesser General Public License along with this library; if not,
       write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

libnbd-1.22.2                                      2025-06-16                               nbd_connect_vsock(3)

       nbd_connect_vsock - connect to NBD server over AF_VSOCK protocol

       If the call is successful the function returns 0.

nbd_aio_connect_vsock(3), nbd_create(3), nbd_set_opt_mode(3), nbd_supports_vsock(3), libnbd(3), vsock(7).

        #include <libnbd.h>

        int nbd_connect_vsock (
              struct nbd_handle *h, uint32_t cid, uint32_t port
            );

       This function first appeared in libnbd 1.2.

       If you need to test if this function is available at compile time check if the following macro is
       defined:

        #define LIBNBD_HAVE_NBD_CONNECT_VSOCK 1