include/block/nbd.h

   1 /*
   2  *  Copyright Red Hat
   3  *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
   4  *
   5  *  Network Block Device
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; under version 2 of the License.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #ifndef NBD_H
  21 #define NBD_H
  22
  23 #include "block/export.h"
  24 #include "io/channel-socket.h"
  25 #include "crypto/tlscreds.h"
  26 #include "qapi/error.h"
  27 #include "qemu/bswap.h"
  28
  29 typedef struct NBDExport NBDExport;
  30 typedef struct NBDClient NBDClient;
  31 typedef struct NBDClientConnection NBDClientConnection;
  32 typedef struct NBDMetaContexts NBDMetaContexts;
  33
  34 extern const BlockExportDriver blk_exp_nbd;
  35
  36 /* Handshake phase structs - this struct is passed on the wire */
  37
  38 typedef struct NBDOption {
  39     uint64_t magic; /* NBD_OPTS_MAGIC */
  40     uint32_t option; /* NBD_OPT_* */
  41     uint32_t length;
  42 } QEMU_PACKED NBDOption;
  43
  44 typedef struct NBDOptionReply {
  45     uint64_t magic; /* NBD_REP_MAGIC */
  46     uint32_t option; /* NBD_OPT_* */
  47     uint32_t type; /* NBD_REP_* */
  48     uint32_t length;
  49 } QEMU_PACKED NBDOptionReply;
  50
  51 typedef struct NBDOptionReplyMetaContext {
  52     NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */
  53     uint32_t context_id;
  54     /* metadata context name follows */
  55 } QEMU_PACKED NBDOptionReplyMetaContext;
  56
  57 /* Track results of negotiation */
  58 typedef enum NBDMode {
  59     /* Keep this list in a continuum of increasing features. */
  60     NBD_MODE_OLDSTYLE,     /* server lacks newstyle negotiation */
  61     NBD_MODE_EXPORT_NAME,  /* newstyle but only OPT_EXPORT_NAME safe */
  62     NBD_MODE_SIMPLE,       /* newstyle but only simple replies */
  63     NBD_MODE_STRUCTURED,   /* newstyle, structured replies enabled */
  64     NBD_MODE_EXTENDED,     /* newstyle, extended headers enabled */
  65 } NBDMode;
  66
  67 /* Transmission phase structs */
  68
  69 /*
  70  * Note: NBDRequest is _NOT_ the same as the network representation of an NBD
  71  * request!
  72  */
  73 typedef struct NBDRequest {
  74     uint64_t cookie;
  75     uint64_t from;  /* Offset touched by the command */
  76     uint64_t len;   /* Effect length; 32 bit limit without extended headers */
  77     uint16_t flags; /* NBD_CMD_FLAG_* */
  78     uint16_t type;  /* NBD_CMD_* */
  79     NBDMode mode;   /* Determines which network representation to use */
  80     NBDMetaContexts *contexts; /* Used by NBD_CMD_BLOCK_STATUS */
  81 } NBDRequest;
  82
  83 typedef struct NBDSimpleReply {
  84     uint32_t magic;  /* NBD_SIMPLE_REPLY_MAGIC */
  85     uint32_t error;
  86     uint64_t cookie;
  87 } QEMU_PACKED NBDSimpleReply;
  88
  89 /* Header of all structured replies */
  90 typedef struct NBDStructuredReplyChunk {
  91     uint32_t magic;  /* NBD_STRUCTURED_REPLY_MAGIC */
  92     uint16_t flags;  /* combination of NBD_REPLY_FLAG_* */
  93     uint16_t type;   /* NBD_REPLY_TYPE_* */
  94     uint64_t cookie; /* request handle */
  95     uint32_t length; /* length of payload */
  96 } QEMU_PACKED NBDStructuredReplyChunk;
  97
  98 typedef struct NBDExtendedReplyChunk {
  99     uint32_t magic;  /* NBD_EXTENDED_REPLY_MAGIC */
 100     uint16_t flags;  /* combination of NBD_REPLY_FLAG_* */
 101     uint16_t type;   /* NBD_REPLY_TYPE_* */
 102     uint64_t cookie; /* request handle */
 103     uint64_t offset; /* request offset */
 104     uint64_t length; /* length of payload */
 105 } QEMU_PACKED NBDExtendedReplyChunk;
 106
 107 typedef union NBDReply {
 108     NBDSimpleReply simple;
 109     NBDStructuredReplyChunk structured;
 110     NBDExtendedReplyChunk extended;
 111     struct {
 112         /*
 113          * @magic and @cookie fields have the same offset and size in all
 114          * forms of replies, so let them be accessible without ".simple.",
 115          * ".structured.", or ".extended." specifications.
 116          */
 117         uint32_t magic;
 118         uint32_t _skip;
 119         uint64_t cookie;
 120     };
 121 } NBDReply;
 122 QEMU_BUILD_BUG_ON(offsetof(NBDReply, simple.cookie) !=
 123                   offsetof(NBDReply, cookie));
 124 QEMU_BUILD_BUG_ON(offsetof(NBDReply, structured.cookie) !=
 125                   offsetof(NBDReply, cookie));
 126 QEMU_BUILD_BUG_ON(offsetof(NBDReply, extended.cookie) !=
 127                   offsetof(NBDReply, cookie));
 128
 129 /* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */
 130 typedef struct NBDStructuredReadData {
 131     /* header's .length >= 9 */
 132     uint64_t offset;
 133     /* At least one byte of data payload follows, calculated from h.length */
 134 } QEMU_PACKED NBDStructuredReadData;
 135
 136 /* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */
 137 typedef struct NBDStructuredReadHole {
 138     /* header's length == 12 */
 139     uint64_t offset;
 140     uint32_t length;
 141 } QEMU_PACKED NBDStructuredReadHole;
 142
 143 /* Header of all NBD_REPLY_TYPE_ERROR* errors */
 144 typedef struct NBDStructuredError {
 145     /* header's length >= 6 */
 146     uint32_t error;
 147     uint16_t message_length;
 148 } QEMU_PACKED NBDStructuredError;
 149
 150 /* Header of NBD_REPLY_TYPE_BLOCK_STATUS */
 151 typedef struct NBDStructuredMeta {
 152     /* header's length >= 12 (at least one extent) */
 153     uint32_t context_id;
 154     /* NBDExtent32 extents[] follows, array length implied by header */
 155 } QEMU_PACKED NBDStructuredMeta;
 156
 157 /* Extent array element for NBD_REPLY_TYPE_BLOCK_STATUS */
 158 typedef struct NBDExtent32 {
 159     uint32_t length;
 160     uint32_t flags; /* NBD_STATE_* */
 161 } QEMU_PACKED NBDExtent32;
 162
 163 /* Header of NBD_REPLY_TYPE_BLOCK_STATUS_EXT */
 164 typedef struct NBDExtendedMeta {
 165     /* header's length >= 24 (at least one extent) */
 166     uint32_t context_id;
 167     uint32_t count; /* header length must be count * 16 + 8 */
 168     /* NBDExtent64 extents[count] follows */
 169 } QEMU_PACKED NBDExtendedMeta;
 170
 171 /* Extent array element for NBD_REPLY_TYPE_BLOCK_STATUS_EXT */
 172 typedef struct NBDExtent64 {
 173     uint64_t length;
 174     uint64_t flags; /* NBD_STATE_* */
 175 } QEMU_PACKED NBDExtent64;
 176
 177 /* Client payload for limiting NBD_CMD_BLOCK_STATUS reply */
 178 typedef struct NBDBlockStatusPayload {
 179     uint64_t effect_length;
 180     /* uint32_t ids[] follows, array length implied by header */
 181 } QEMU_PACKED NBDBlockStatusPayload;
 182
 183 /* Transmission (export) flags: sent from server to client during handshake,
 184    but describe what will happen during transmission */
 185 enum {
 186     NBD_FLAG_HAS_FLAGS_BIT          =  0, /* Flags are there */
 187     NBD_FLAG_READ_ONLY_BIT          =  1, /* Device is read-only */
 188     NBD_FLAG_SEND_FLUSH_BIT         =  2, /* Send FLUSH */
 189     NBD_FLAG_SEND_FUA_BIT           =  3, /* Send FUA (Force Unit Access) */
 190     NBD_FLAG_ROTATIONAL_BIT         =  4, /* Use elevator algorithm -
 191                                              rotational media */
 192     NBD_FLAG_SEND_TRIM_BIT          =  5, /* Send TRIM (discard) */
 193     NBD_FLAG_SEND_WRITE_ZEROES_BIT  =  6, /* Send WRITE_ZEROES */
 194     NBD_FLAG_SEND_DF_BIT            =  7, /* Send DF (Do not Fragment) */
 195     NBD_FLAG_CAN_MULTI_CONN_BIT     =  8, /* Multi-client cache consistent */
 196     NBD_FLAG_SEND_RESIZE_BIT        =  9, /* Send resize */
 197     NBD_FLAG_SEND_CACHE_BIT         = 10, /* Send CACHE (prefetch) */
 198     NBD_FLAG_SEND_FAST_ZERO_BIT     = 11, /* FAST_ZERO flag for WRITE_ZEROES */
 199     NBD_FLAG_BLOCK_STAT_PAYLOAD_BIT = 12, /* PAYLOAD flag for BLOCK_STATUS */
 200 };
 201
 202 #define NBD_FLAG_HAS_FLAGS          (1 << NBD_FLAG_HAS_FLAGS_BIT)
 203 #define NBD_FLAG_READ_ONLY          (1 << NBD_FLAG_READ_ONLY_BIT)
 204 #define NBD_FLAG_SEND_FLUSH         (1 << NBD_FLAG_SEND_FLUSH_BIT)
 205 #define NBD_FLAG_SEND_FUA           (1 << NBD_FLAG_SEND_FUA_BIT)
 206 #define NBD_FLAG_ROTATIONAL         (1 << NBD_FLAG_ROTATIONAL_BIT)
 207 #define NBD_FLAG_SEND_TRIM          (1 << NBD_FLAG_SEND_TRIM_BIT)
 208 #define NBD_FLAG_SEND_WRITE_ZEROES  (1 << NBD_FLAG_SEND_WRITE_ZEROES_BIT)
 209 #define NBD_FLAG_SEND_DF            (1 << NBD_FLAG_SEND_DF_BIT)
 210 #define NBD_FLAG_CAN_MULTI_CONN     (1 << NBD_FLAG_CAN_MULTI_CONN_BIT)
 211 #define NBD_FLAG_SEND_RESIZE        (1 << NBD_FLAG_SEND_RESIZE_BIT)
 212 #define NBD_FLAG_SEND_CACHE         (1 << NBD_FLAG_SEND_CACHE_BIT)
 213 #define NBD_FLAG_SEND_FAST_ZERO     (1 << NBD_FLAG_SEND_FAST_ZERO_BIT)
 214 #define NBD_FLAG_BLOCK_STAT_PAYLOAD (1 << NBD_FLAG_BLOCK_STAT_PAYLOAD_BIT)
 215
 216 /* New-style handshake (global) flags, sent from server to client, and
 217    control what will happen during handshake phase. */
 218 #define NBD_FLAG_FIXED_NEWSTYLE   (1 << 0) /* Fixed newstyle protocol. */
 219 #define NBD_FLAG_NO_ZEROES        (1 << 1) /* End handshake without zeroes. */
 220
 221 /* New-style client flags, sent from client to server to control what happens
 222    during handshake phase. */
 223 #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
 224 #define NBD_FLAG_C_NO_ZEROES      (1 << 1) /* End handshake without zeroes. */
 225
 226 /* Option requests. */
 227 #define NBD_OPT_EXPORT_NAME       (1)
 228 #define NBD_OPT_ABORT             (2)
 229 #define NBD_OPT_LIST              (3)
 230 /* #define NBD_OPT_PEEK_EXPORT    (4) not in use */
 231 #define NBD_OPT_STARTTLS          (5)
 232 #define NBD_OPT_INFO              (6)
 233 #define NBD_OPT_GO                (7)
 234 #define NBD_OPT_STRUCTURED_REPLY  (8)
 235 #define NBD_OPT_LIST_META_CONTEXT (9)
 236 #define NBD_OPT_SET_META_CONTEXT  (10)
 237 #define NBD_OPT_EXTENDED_HEADERS  (11)
 238
 239 /* Option reply types. */
 240 #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value))
 241
 242 #define NBD_REP_ACK             (1)    /* Data sending finished. */
 243 #define NBD_REP_SERVER          (2)    /* Export description. */
 244 #define NBD_REP_INFO            (3)    /* NBD_OPT_INFO/GO. */
 245 #define NBD_REP_META_CONTEXT    (4)    /* NBD_OPT_{LIST,SET}_META_CONTEXT */
 246
 247 #define NBD_REP_ERR_UNSUP           NBD_REP_ERR(1)  /* Unknown option */
 248 #define NBD_REP_ERR_POLICY          NBD_REP_ERR(2)  /* Server denied */
 249 #define NBD_REP_ERR_INVALID         NBD_REP_ERR(3)  /* Invalid length */
 250 #define NBD_REP_ERR_PLATFORM        NBD_REP_ERR(4)  /* Not compiled in */
 251 #define NBD_REP_ERR_TLS_REQD        NBD_REP_ERR(5)  /* TLS required */
 252 #define NBD_REP_ERR_UNKNOWN         NBD_REP_ERR(6)  /* Export unknown */
 253 #define NBD_REP_ERR_SHUTDOWN        NBD_REP_ERR(7)  /* Server shutting down */
 254 #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8)  /* Need INFO_BLOCK_SIZE */
 255 #define NBD_REP_ERR_TOO_BIG         NBD_REP_ERR(9)  /* Payload size overflow */
 256 #define NBD_REP_ERR_EXT_HEADER_REQD NBD_REP_ERR(10) /* Need extended headers */
 257
 258 /* Info types, used during NBD_REP_INFO */
 259 #define NBD_INFO_EXPORT         0
 260 #define NBD_INFO_NAME           1
 261 #define NBD_INFO_DESCRIPTION    2
 262 #define NBD_INFO_BLOCK_SIZE     3
 263
 264 /* Request flags, sent from client to server during transmission phase */
 265 #define NBD_CMD_FLAG_FUA         (1 << 0) /* 'force unit access' during write */
 266 #define NBD_CMD_FLAG_NO_HOLE     (1 << 1) /* don't punch hole on zero run */
 267 #define NBD_CMD_FLAG_DF          (1 << 2) /* don't fragment structured read */
 268 #define NBD_CMD_FLAG_REQ_ONE     (1 << 3) \
 269     /* only one extent in BLOCK_STATUS reply chunk */
 270 #define NBD_CMD_FLAG_FAST_ZERO   (1 << 4) /* fail if WRITE_ZEROES is not fast */
 271 #define NBD_CMD_FLAG_PAYLOAD_LEN (1 << 5) \
 272     /* length describes payload, not effect; only with ext header */
 273
 274 /* Supported request types */
 275 enum {
 276     NBD_CMD_READ = 0,
 277     NBD_CMD_WRITE = 1,
 278     NBD_CMD_DISC = 2,
 279     NBD_CMD_FLUSH = 3,
 280     NBD_CMD_TRIM = 4,
 281     NBD_CMD_CACHE = 5,
 282     NBD_CMD_WRITE_ZEROES = 6,
 283     NBD_CMD_BLOCK_STATUS = 7,
 284 };
 285
 286 #define NBD_DEFAULT_PORT        10809
 287
 288 /* Maximum size of a single READ/WRITE data buffer */
 289 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
 290
 291 /*
 292  * Maximum size of a protocol string (export name, metadata context name,
 293  * etc.).  Use malloc rather than stack allocation for storage of a
 294  * string.
 295  */
 296 #define NBD_MAX_STRING_SIZE 4096
 297
 298 /* Two types of request structures, a given client will only use 1 */
 299 #define NBD_REQUEST_MAGIC           0x25609513
 300 #define NBD_EXTENDED_REQUEST_MAGIC  0x21e41c71
 301
 302 /*
 303  * Three types of reply structures, but what a client expects depends
 304  * on NBD_OPT_STRUCTURED_REPLY and NBD_OPT_EXTENDED_HEADERS.
 305  */
 306 #define NBD_SIMPLE_REPLY_MAGIC      0x67446698
 307 #define NBD_STRUCTURED_REPLY_MAGIC  0x668e33ef
 308 #define NBD_EXTENDED_REPLY_MAGIC    0x6e8a278c
 309
 310 /* Chunk reply flags (for structured and extended replies) */
 311 #define NBD_REPLY_FLAG_DONE          (1 << 0) /* This reply-chunk is last */
 312
 313 /* Chunk reply types */
 314 #define NBD_REPLY_ERR(value)         ((1 << 15) | (value))
 315
 316 #define NBD_REPLY_TYPE_NONE              0
 317 #define NBD_REPLY_TYPE_OFFSET_DATA       1
 318 #define NBD_REPLY_TYPE_OFFSET_HOLE       2
 319 #define NBD_REPLY_TYPE_BLOCK_STATUS      5
 320 #define NBD_REPLY_TYPE_BLOCK_STATUS_EXT  6
 321 #define NBD_REPLY_TYPE_ERROR             NBD_REPLY_ERR(1)
 322 #define NBD_REPLY_TYPE_ERROR_OFFSET      NBD_REPLY_ERR(2)
 323
 324 /* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */
 325 #define NBD_STATE_HOLE (1 << 0)
 326 #define NBD_STATE_ZERO (1 << 1)
 327
 328 /* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */
 329 #define NBD_STATE_DIRTY (1 << 0)
 330
 331 /* No flags needed for qemu:allocation-depth in NBD_REPLY_TYPE_BLOCK_STATUS */
 332
 333 static inline bool nbd_reply_type_is_error(int type)
 334 {
 335     return type & (1 << 15);
 336 }
 337
 338 /* NBD errors are based on errno numbers, so there is a 1:1 mapping,
 339  * but only a limited set of errno values is specified in the protocol.
 340  * Everything else is squashed to EINVAL.
 341  */
 342 #define NBD_SUCCESS    0
 343 #define NBD_EPERM      1
 344 #define NBD_EIO        5
 345 #define NBD_ENOMEM     12
 346 #define NBD_EINVAL     22
 347 #define NBD_ENOSPC     28
 348 #define NBD_EOVERFLOW  75
 349 #define NBD_ENOTSUP    95
 350 #define NBD_ESHUTDOWN  108
 351
 352 /* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */
 353 typedef struct NBDExportInfo {
 354     /* Set by client before nbd_receive_negotiate() */
 355     bool request_sizes;
 356     char *x_dirty_bitmap;
 357
 358     /* Set by client before nbd_receive_negotiate(), or by server results
 359      * during nbd_receive_export_list() */
 360     char *name; /* must be non-NULL */
 361
 362     /* In-out fields, set by client before nbd_receive_negotiate() and
 363      * updated by server results during nbd_receive_negotiate() */
 364     NBDMode mode; /* input maximum mode tolerated; output actual mode chosen */
 365     bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */
 366
 367     /* Set by server results during nbd_receive_negotiate() and
 368      * nbd_receive_export_list() */
 369     uint64_t size;
 370     uint16_t flags;
 371     uint32_t min_block;
 372     uint32_t opt_block;
 373     uint32_t max_block;
 374
 375     uint32_t context_id;
 376
 377     /* Set by server results during nbd_receive_export_list() */
 378     char *description;
 379     int n_contexts;
 380     char **contexts;
 381 } NBDExportInfo;
 382
 383 int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
 384                           const char *hostname, QIOChannel **outioc,
 385                           NBDExportInfo *info, Error **errp);
 386 void nbd_free_export_list(NBDExportInfo *info, int count);
 387 int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
 388                             const char *hostname, NBDExportInfo **info,
 389                             Error **errp);
 390 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
 391              Error **errp);
 392 int nbd_send_request(QIOChannel *ioc, NBDRequest *request);
 393 int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
 394                                    NBDReply *reply, NBDMode mode,
 395                                    Error **errp);
 396 int nbd_client(int fd);
 397 int nbd_disconnect(int fd);
 398 int nbd_errno_to_system_errno(int err);
 399
 400 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk);
 401
 402 AioContext *nbd_export_aio_context(NBDExport *exp);
 403 NBDExport *nbd_export_find(const char *name);
 404
 405 void nbd_client_new(QIOChannelSocket *sioc,
 406                     QCryptoTLSCreds *tlscreds,
 407                     const char *tlsauthz,
 408                     void (*close_fn)(NBDClient *, bool));
 409 void nbd_client_get(NBDClient *client);
 410 void nbd_client_put(NBDClient *client);
 411
 412 void nbd_server_is_qemu_nbd(int max_connections);
 413 bool nbd_server_is_running(void);
 414 int nbd_server_max_connections(void);
 415 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
 416                       const char *tls_authz, uint32_t max_connections,
 417                       Error **errp);
 418 void nbd_server_start_options(NbdServerOptions *arg, Error **errp);
 419
 420 /* nbd_read
 421  * Reads @size bytes from @ioc. Returns 0 on success.
 422  */
 423 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
 424                            const char *desc, Error **errp)
 425 {
 426     ERRP_GUARD();
 427     int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
 428
 429     if (ret < 0) {
 430         if (desc) {
 431             error_prepend(errp, "Failed to read %s: ", desc);
 432         }
 433         return ret;
 434     }
 435
 436     return 0;
 437 }
 438
 439 #define DEF_NBD_READ_N(bits)                                            \
 440 static inline int nbd_read##bits(QIOChannel *ioc,                       \
 441                                  uint##bits##_t *val,                   \
 442                                  const char *desc, Error **errp)        \
 443 {                                                                       \
 444     int ret = nbd_read(ioc, val, sizeof(*val), desc, errp);             \
 445     if (ret < 0) {                                                      \
 446         return ret;                                                     \
 447     }                                                                   \
 448     *val = be##bits##_to_cpu(*val);                                     \
 449     return 0;                                                           \
 450 }
 451
 452 DEF_NBD_READ_N(16) /* Defines nbd_read16(). */
 453 DEF_NBD_READ_N(32) /* Defines nbd_read32(). */
 454 DEF_NBD_READ_N(64) /* Defines nbd_read64(). */
 455
 456 #undef DEF_NBD_READ_N
 457
 458 static inline bool nbd_reply_is_simple(NBDReply *reply)
 459 {
 460     return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
 461 }
 462
 463 static inline bool nbd_reply_is_structured(NBDReply *reply)
 464 {
 465     return reply->magic == NBD_STRUCTURED_REPLY_MAGIC;
 466 }
 467
 468 const char *nbd_reply_type_lookup(uint16_t type);
 469 const char *nbd_opt_lookup(uint32_t opt);
 470 const char *nbd_rep_lookup(uint32_t rep);
 471 const char *nbd_info_lookup(uint16_t info);
 472 const char *nbd_cmd_lookup(uint16_t info);
 473 const char *nbd_err_lookup(int err);
 474 const char *nbd_mode_lookup(NBDMode mode);
 475
 476 /* nbd/client-connection.c */
 477 void nbd_client_connection_enable_retry(NBDClientConnection *conn);
 478
 479 NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr,
 480                                                bool do_negotiation,
 481                                                const char *export_name,
 482                                                const char *x_dirty_bitmap,
 483                                                QCryptoTLSCreds *tlscreds,
 484                                                const char *tlshostname);
 485 void nbd_client_connection_release(NBDClientConnection *conn);
 486
 487 QIOChannel *coroutine_fn
 488 nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info,
 489                             bool blocking, Error **errp);
 490
 491 void nbd_co_establish_connection_cancel(NBDClientConnection *conn);
 492
 493 #endif