protocol-handshake-oldstyle.c

/* nbdkit
 * Copyright Red Hat
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of Red Hat nor the names of its contributors may be
 * used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>

#include "internal.h"
#include "byte-swapping.h"
#include "nbd-protocol.h"

int
protocol_handshake_oldstyle (void)
{
  GET_CONN;
  struct nbd_old_handshake handshake;
  uint64_t exportsize;
  uint16_t gflags, eflags;

  assert (tls != 2); /* Already filtered in main */

  /* With oldstyle, our only option if .open or friends fail is to
   * disconnect, as we cannot report the problem to the client.
   */
  if (protocol_common_open (&exportsize, &eflags, "") == -1)
    return -1;

  gflags = 0;
  debug ("oldstyle negotiation: flags: global 0x%x export 0x%x",
         gflags, eflags);

  memset (&handshake, 0, sizeof handshake);
  handshake.nbdmagic = htobe64 (NBD_MAGIC);
  handshake.version = htobe64 (NBD_OLD_VERSION);
  handshake.exportsize = htobe64 (exportsize);
  handshake.gflags = htobe16 (gflags);
  handshake.eflags = htobe16 (eflags);

  if (conn->send (&handshake, sizeof handshake, 0) == -1) {
    nbdkit_error ("write: %m");
    return -1;
  }

  return 0;
}