NAME

       nbd_connect_uri - connect to NBD URI

SYNOPSIS

        #include <libnbd.h>

        int nbd_connect_uri (struct nbd_handle *h, const char *uri);

DESCRIPTION

       Connect (synchronously) to an NBD server and export by specifying the NBD URI.  This call
       parses the URI and may call nbd_set_export_name(3) and nbd_set_tls(3) and other calls as
       needed, followed by nbd_connect_tcp(3) or nbd_connect_unix(3).  This call returns when the
       connection has been made.

   Example URIs supported
       "nbd://example.com"
           Connect over TCP, unencrypted, to "example.com" port 10809.

       "nbds://example.com"
           Connect over TCP with TLS, to "example.com" port 10809.  If the server does not
           support TLS then this will fail.

       "nbd+unix:///foo?socket=/tmp/nbd.sock"
           Connect over the Unix domain socket /tmp/nbd.sock to an NBD server running locally.
           The export name is set to "foo" (note without any leading "/" character).

       "nbd+vsock:///"
           In this scenario libnbd is running in a virtual machine.  Connect over "AF_VSOCK" to
           an NBD server running on the hypervisor.

   Supported URI formats
       The following schemes are supported in the current version of libnbd:

       "nbd:"
           Connect over TCP without using TLS.

       "nbds:"
           Connect over TCP.  TLS is required and the connection will fail if the server does not
           support TLS.

       "nbd+unix:"
       "nbds+unix:"
           Connect over a Unix domain socket, without or with TLS respectively.  The "socket"
           parameter is required.

       "nbd+vsock:"
       "nbds+vsock:"
           Connect over the "AF_VSOCK" transport, without or with TLS respectively.

       The authority part of the URI ("[username@][servername][:port]") is parsed depending on
       the transport.  For TCP it specifies the server to connect to and optional port number.
       For "+unix" it should not be present.  For "+vsock" the server name is the numeric CID
       (eg. 2 to connect to the host), and the optional port number may be present.  If the
       "username" is present it is used for TLS authentication.

       For all transports, an export name may be present, parsed in accordance with the NBD URI
       specification.

       Finally the query part of the URI can contain:

       socket=SOCKET
           Specifies the Unix domain socket to connect on.  Must be present for the "+unix"
           transport and must not be present for the other transports.

       tls-psk-file=PSKFILE
           Set the PSK file.  See nbd_set_tls_psk_file(3).  Note this is not allowed by default -
           see next section.

   Disable URI features
       For security reasons you might want to disable certain URI features.  Pre-filtering URIs
       is error-prone and should not be attempted.  Instead use the libnbd APIs below to control
       what can appear in URIs.  Note you must call these functions on the same handle before
       calling "nbd_connect_uri" or nbd_aio_connect_uri(3).

       TCP, Unix domain socket or "AF_VSOCK" transports
           Default: all allowed

           To select which transports are allowed call nbd_set_uri_allow_transports(3).

       TLS Default: both non-TLS and TLS connections allowed

           To force TLS off or on in URIs call nbd_set_uri_allow_tls(3).

       Connect to Unix domain socket in the local filesystem
           Default: allowed

           To prevent this you must disable the "+unix" transport using
           nbd_set_uri_allow_transports(3).

       Read from local files
           Default: denied

           To allow URIs to contain references to local files (eg. for parameters like
           "tls-psk-file") call nbd_set_uri_allow_local_file(3).

   Optional features
       This call will fail if libnbd was not compiled with libxml2; you can test whether this is
       the case with nbd_supports_uri(3).

       Support for URIs that require TLS will fail if libnbd was not compiled with gnutls; you
       can test whether this is the case with nbd_supports_tls(3).

RETURN VALUE

       If the call is successful the function returns 0.

ERRORS

       On error "-1" is returned.

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

HANDLE STATE

       The handle must be newly created, otherwise this call will return an error.

VERSION

       This function first appeared in libnbd 1.0.

       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_URI 1

SEE ALSO

       https://github.com/NetworkBlockDevice/nbd/blob/master/doc/uri.md, nbd_create(3),
       libnbd(3).

AUTHORS

       Eric Blake

       Richard W.M. Jones

COPYRIGHT

       Copyright (C) 2019 Red Hat Inc.

LICENSE

       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