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
  23 #include "qemu-common.h"
  24 #include "qemu/option.h"
  25 #include "io/channel-socket.h"
  26 #include "crypto/tlscreds.h"
  27
  28 /* Note: these are _NOT_ the same as the network representation of an NBD
  29  * request and reply!
  30  */
  31 struct nbd_request {
  32     uint64_t handle;
  33     uint64_t from;
  34     uint32_t len;
  35     uint32_t type;
  36 };
  37
  38 struct nbd_reply {
  39     uint64_t handle;
  40     uint32_t error;
  41 };
  42
  43 #define NBD_FLAG_HAS_FLAGS      (1 << 0)        /* Flags are there */
  44 #define NBD_FLAG_READ_ONLY      (1 << 1)        /* Device is read-only */
  45 #define NBD_FLAG_SEND_FLUSH     (1 << 2)        /* Send FLUSH */
  46 #define NBD_FLAG_SEND_FUA       (1 << 3)        /* Send FUA (Force Unit Access) */
  47 #define NBD_FLAG_ROTATIONAL     (1 << 4)        /* Use elevator algorithm - rotational media */
  48 #define NBD_FLAG_SEND_TRIM      (1 << 5)        /* Send TRIM (discard) */
  49
  50 /* New-style global flags. */
  51 #define NBD_FLAG_FIXED_NEWSTYLE     (1 << 0)    /* Fixed newstyle protocol. */
  52
  53 /* New-style client flags. */
  54 #define NBD_FLAG_C_FIXED_NEWSTYLE   (1 << 0)    /* Fixed newstyle protocol. */
  55
  56 /* Reply types. */
  57 #define NBD_REP_ACK             (1)             /* Data sending finished. */
  58 #define NBD_REP_SERVER          (2)             /* Export description. */
  59 #define NBD_REP_ERR_UNSUP       ((UINT32_C(1) << 31) | 1) /* Unknown option. */
  60 #define NBD_REP_ERR_POLICY      ((UINT32_C(1) << 31) | 2) /* Server denied */
  61 #define NBD_REP_ERR_INVALID     ((UINT32_C(1) << 31) | 3) /* Invalid length. */
  62 #define NBD_REP_ERR_TLS_REQD    ((UINT32_C(1) << 31) | 5) /* TLS required */
  63
  64
  65 #define NBD_CMD_MASK_COMMAND    0x0000ffff
  66 #define NBD_CMD_FLAG_FUA        (1 << 16)
  67
  68 enum {
  69     NBD_CMD_READ = 0,
  70     NBD_CMD_WRITE = 1,
  71     NBD_CMD_DISC = 2,
  72     NBD_CMD_FLUSH = 3,
  73     NBD_CMD_TRIM = 4
  74 };
  75
  76 #define NBD_DEFAULT_PORT        10809
  77
  78 /* Maximum size of a single READ/WRITE data buffer */
  79 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
  80 /* Maximum size of an export name. The NBD spec requires 256 and
  81  * suggests that servers support up to 4096, but we stick to only the
  82  * required size so that we can stack-allocate the names, and because
  83  * going larger would require an audit of more code to make sure we
  84  * aren't overflowing some other buffer. */
  85 #define NBD_MAX_NAME_SIZE 256
  86
  87 ssize_t nbd_wr_syncv(QIOChannel *ioc,
  88                      struct iovec *iov,
  89                      size_t niov,
  90                      size_t offset,
  91                      size_t length,
  92                      bool do_read);
  93 int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags,
  94                           QCryptoTLSCreds *tlscreds, const char *hostname,
  95                           QIOChannel **outioc,
  96                           off_t *size, Error **errp);
  97 int nbd_init(int fd, QIOChannelSocket *sioc, uint32_t flags, off_t size);
  98 ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request);
  99 ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply);
 100 int nbd_client(int fd);
 101 int nbd_disconnect(int fd);
 102
 103 typedef struct NBDExport NBDExport;
 104 typedef struct NBDClient NBDClient;
 105
 106 NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
 107                           uint32_t nbdflags, void (*close)(NBDExport *),
 108                           Error **errp);
 109 void nbd_export_close(NBDExport *exp);
 110 void nbd_export_get(NBDExport *exp);
 111 void nbd_export_put(NBDExport *exp);
 112
 113 BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
 114
 115 NBDExport *nbd_export_find(const char *name);
 116 void nbd_export_set_name(NBDExport *exp, const char *name);
 117 void nbd_export_close_all(void);
 118
 119 void nbd_client_new(NBDExport *exp,
 120                     QIOChannelSocket *sioc,
 121                     QCryptoTLSCreds *tlscreds,
 122                     const char *tlsaclname,
 123                     void (*close)(NBDClient *));
 124 void nbd_client_get(NBDClient *client);
 125 void nbd_client_put(NBDClient *client);
 126
 127 #endif