server/protocol-handshake-oldstyle.c

   1 /* nbdkit
   2  * Copyright (C) 2013-2019 Red Hat Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <stdint.h>
  38 #include <inttypes.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41
  42 #include "internal.h"
  43 #include "byte-swapping.h"
  44 #include "nbd-protocol.h"
  45
  46 int
  47 protocol_handshake_oldstyle (struct connection *conn)
  48 {
  49   struct nbd_old_handshake handshake;
  50   uint64_t exportsize;
  51   uint16_t gflags, eflags;
  52
  53   assert (tls != 2); /* Already filtered in main */
  54
  55   /* With oldstyle, our only option if .open or friends fail is to
  56    * disconnect, as we cannot report the problem to the client.
  57    */
  58   if (protocol_common_open (conn, &exportsize, &eflags) == -1)
  59     return -1;
  60
  61   gflags = 0;
  62   debug ("oldstyle negotiation: flags: global 0x%x export 0x%x",
  63          gflags, eflags);
  64
  65   memset (&handshake, 0, sizeof handshake);
  66   handshake.nbdmagic = htobe64 (NBD_MAGIC);
  67   handshake.version = htobe64 (NBD_OLD_VERSION);
  68   handshake.exportsize = htobe64 (exportsize);
  69   handshake.gflags = htobe16 (gflags);
  70   handshake.eflags = htobe16 (eflags);
  71
  72   if (conn->send (conn, &handshake, sizeof handshake, 0) == -1) {
  73     nbdkit_error ("write: %m");
  74     return -1;
  75   }
  76
  77   return 0;
  78 }