include/block/nbd.h

   1 /*
   2  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   3  *
   4  *  Network Block Device
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; under version 2 of the License.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #ifndef NBD_H
  20 #define NBD_H
  21
  22 #include <sys/types.h>
  23
  24 #include "qemu-common.h"
  25 #include "qemu/option.h"
  26
  27 struct nbd_request {
  28     uint32_t magic;
  29     uint32_t type;
  30     uint64_t handle;
  31     uint64_t from;
  32     uint32_t len;
  33 } QEMU_PACKED;
  34
  35 struct nbd_reply {
  36     uint32_t magic;
  37     uint32_t error;
  38     uint64_t handle;
  39 } QEMU_PACKED;
  40
  41 #define NBD_FLAG_HAS_FLAGS      (1 << 0)        /* Flags are there */
  42 #define NBD_FLAG_READ_ONLY      (1 << 1)        /* Device is read-only */
  43 #define NBD_FLAG_SEND_FLUSH     (1 << 2)        /* Send FLUSH */
  44 #define NBD_FLAG_SEND_FUA       (1 << 3)        /* Send FUA (Force Unit Access) */
  45 #define NBD_FLAG_ROTATIONAL     (1 << 4)        /* Use elevator algorithm - rotational media */
  46 #define NBD_FLAG_SEND_TRIM      (1 << 5)        /* Send TRIM (discard) */
  47
  48 /* New-style global flags. */
  49 #define NBD_FLAG_FIXED_NEWSTYLE     (1 << 0)    /* Fixed newstyle protocol. */
  50
  51 /* New-style client flags. */
  52 #define NBD_FLAG_C_FIXED_NEWSTYLE   (1 << 0)    /* Fixed newstyle protocol. */
  53
  54 /* Reply types. */
  55 #define NBD_REP_ACK             (1)             /* Data sending finished. */
  56 #define NBD_REP_SERVER          (2)             /* Export description. */
  57 #define NBD_REP_ERR_UNSUP       ((1 << 31) | 1) /* Unknown option. */
  58 #define NBD_REP_ERR_INVALID     ((1 << 31) | 3) /* Invalid length. */
  59
  60 #define NBD_CMD_MASK_COMMAND    0x0000ffff
  61 #define NBD_CMD_FLAG_FUA        (1 << 16)
  62
  63 enum {
  64     NBD_CMD_READ = 0,
  65     NBD_CMD_WRITE = 1,
  66     NBD_CMD_DISC = 2,
  67     NBD_CMD_FLUSH = 3,
  68     NBD_CMD_TRIM = 4
  69 };
  70
  71 #define NBD_DEFAULT_PORT        10809
  72
  73 /* Maximum size of a single READ/WRITE data buffer */
  74 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
  75
  76 ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
  77 int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
  78                           off_t *size, size_t *blocksize);
  79 int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize);
  80 ssize_t nbd_send_request(int csock, struct nbd_request *request);
  81 ssize_t nbd_receive_reply(int csock, struct nbd_reply *reply);
  82 int nbd_client(int fd);
  83 int nbd_disconnect(int fd);
  84
  85 typedef struct NBDExport NBDExport;
  86 typedef struct NBDClient NBDClient;
  87
  88 NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
  89                           uint32_t nbdflags, void (*close)(NBDExport *));
  90 void nbd_export_close(NBDExport *exp);
  91 void nbd_export_get(NBDExport *exp);
  92 void nbd_export_put(NBDExport *exp);
  93
  94 BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
  95
  96 NBDExport *nbd_export_find(const char *name);
  97 void nbd_export_set_name(NBDExport *exp, const char *name);
  98 void nbd_export_close_all(void);
  99
 100 NBDClient *nbd_client_new(NBDExport *exp, int csock,
 101                           void (*close)(NBDClient *));
 102 void nbd_client_close(NBDClient *client);
 103 void nbd_client_get(NBDClient *client);
 104 void nbd_client_put(NBDClient *client);
 105
 106 #endif