plucky (3) nbd_get_tls_negotiated.3.gz

Provided by: libnbd-dev_1.22.0-1_amd64 bug

NAME
       nbd_get_tls_negotiated - find out if TLS was negotiated on a connection


SYNOPSIS
        #include <libnbd.h>

        int nbd_get_tls_negotiated (
              struct nbd_handle *h
            );


DESCRIPTION
       After connecting you may call this to find out if the connection is using TLS.

       This is normally useful only if you set the TLS request mode to "LIBNBD_TLS_ALLOW" (see nbd_set_tls(3)),
       because in this mode we try to use TLS but fall back to unencrypted if it was not available.  This
       function will tell you if TLS was negotiated or not.

       In "LIBNBD_TLS_REQUIRE" mode (the most secure) the connection would have failed if TLS could not be
       negotiated.  With "LIBNBD_TLS_DISABLE" mode, TLS is not tried automatically; but if the NBD server uses
       the less-common "SELECTIVETLS" mode, this function reports whether a manual nbd_opt_starttls(3) enabled
       TLS or if the connection is still plaintext.


RETURN VALUE
       This call returns a boolean value.


ERRORS
       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).


HANDLE STATE
       nbd_get_tls_negotiated can be called when the handle is in the following states:

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


VERSION
       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_GET_TLS_NEGOTIATED 1


SEE ALSO
       nbd_create(3), nbd_get_tls(3), nbd_opt_starttls(3), nbd_set_tls(3), libnbd(3).


AUTHORS
       Eric Blake

       Richard W.M. Jones


       Copyright Red Hat


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