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 "protocol.h"
  45
  46 int
  47 protocol_handshake_oldstyle (struct connection *conn)
  48 {
  49   struct old_handshake handshake;
  50   int64_t r;
  51   uint64_t exportsize;
  52   uint16_t gflags, eflags;
  53
  54   /* In --tls=require / FORCEDTLS mode, old style handshakes are
  55    * rejected because they cannot support TLS.
  56    */
  57   if (tls == 2) {
  58     nbdkit_error ("non-TLS client tried to connect in --tls=require mode");
  59     return -1;
  60   }
  61
  62   r = backend->get_size (backend, conn);
  63   if (r == -1)
  64     return -1;
  65   if (r < 0) {
  66     nbdkit_error (".get_size function returned invalid value "
  67                   "(%" PRIi64 ")", r);
  68     return -1;
  69   }
  70   exportsize = (uint64_t) r;
  71   conn->exportsize = exportsize;
  72
  73   gflags = 0;
  74   if (protocol_compute_eflags (conn, &eflags) < 0)
  75     return -1;
  76
  77   debug ("oldstyle negotiation: flags: global 0x%x export 0x%x",
  78          gflags, eflags);
  79
  80   memset (&handshake, 0, sizeof handshake);
  81   memcpy (handshake.nbdmagic, "NBDMAGIC", 8);
  82   handshake.version = htobe64 (OLD_VERSION);
  83   handshake.exportsize = htobe64 (exportsize);
  84   handshake.gflags = htobe16 (gflags);
  85   handshake.eflags = htobe16 (eflags);
  86
  87   if (conn->send (conn, &handshake, sizeof handshake, 0) == -1) {
  88     nbdkit_error ("write: %m");
  89     return -1;
  90   }
  91
  92   return 0;
  93 }