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 /*
  37  * NBD_DEFAULT_HANDSHAKE_MAX_SECS: Number of seconds in which client must
  38  * succeed at NBD_OPT_GO before being forcefully dropped as too slow.
  39  */
  40 #define NBD_DEFAULT_HANDSHAKE_MAX_SECS 10
  41
  42 /*
  43  * NBD_DEFAULT_MAX_CONNECTIONS: Number of client sockets to allow at
  44  * once; must be large enough to allow a MULTI_CONN-aware client like
  45  * nbdcopy to create its typical number of 8-16 sockets.
  46  */
  47 #define NBD_DEFAULT_MAX_CONNECTIONS 100
  48
  49 /* Handshake phase structs - this struct is passed on the wire */
  50
  51 typedef struct NBDOption {
  52     uint64_t magic; /* NBD_OPTS_MAGIC */
  53     uint32_t option; /* NBD_OPT_* */
  54     uint32_t length;
  55 } QEMU_PACKED NBDOption;
  56
  57 typedef struct NBDOptionReply {
  58     uint64_t magic; /* NBD_REP_MAGIC */
  59     uint32_t option; /* NBD_OPT_* */
  60     uint32_t type; /* NBD_REP_* */
  61     uint32_t length;
  62 } QEMU_PACKED NBDOptionReply;
  63
  64 typedef struct NBDOptionReplyMetaContext {
  65     NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */
  66     uint32_t context_id;
  67     /* metadata context name follows */
  68 } QEMU_PACKED NBDOptionReplyMetaContext;
  69
  70 /* Track results of negotiation */
  71 typedef enum NBDMode {
  72     /* Keep this list in a continuum of increasing features. */
  73     NBD_MODE_OLDSTYLE,     /* server lacks newstyle negotiation */
  74     NBD_MODE_EXPORT_NAME,  /* newstyle but only OPT_EXPORT_NAME safe */
  75     NBD_MODE_SIMPLE,       /* newstyle but only simple replies */
  76     NBD_MODE_STRUCTURED,   /* newstyle, structured replies enabled */
  77     NBD_MODE_EXTENDED,     /* newstyle, extended headers enabled */
  78 } NBDMode;
  79
  80 /* Transmission phase structs */
  81
  82 /*
  83  * Note: NBDRequest is _NOT_ the same as the network representation of an NBD
  84  * request!
  85  */
  86 typedef struct NBDRequest {
  87     uint64_t cookie;
  88     uint64_t from;  /* Offset touched by the command */
  89     uint64_t len;   /* Effect length; 32 bit limit without extended headers */
  90     uint16_t flags; /* NBD_CMD_FLAG_* */
  91     uint16_t type;  /* NBD_CMD_* */
  92     NBDMode mode;   /* Determines which network representation to use */
  93     NBDMetaContexts *contexts; /* Used by NBD_CMD_BLOCK_STATUS */
  94 } NBDRequest;
  95
  96 typedef struct NBDSimpleReply {
  97     uint32_t magic;  /* NBD_SIMPLE_REPLY_MAGIC */
  98     uint32_t error;
  99     uint64_t cookie;
 100 } QEMU_PACKED NBDSimpleReply;
 101
 102 /* Header of all structured replies */
 103 typedef struct NBDStructuredReplyChunk {
 104     uint32_t magic;  /* NBD_STRUCTURED_REPLY_MAGIC */
 105     uint16_t flags;  /* combination of NBD_REPLY_FLAG_* */
 106     uint16_t type;   /* NBD_REPLY_TYPE_* */
 107     uint64_t cookie; /* request handle */
 108     uint32_t length; /* length of payload */
 109 } QEMU_PACKED NBDStructuredReplyChunk;
 110
 111 typedef struct NBDExtendedReplyChunk {
 112     uint32_t magic;  /* NBD_EXTENDED_REPLY_MAGIC */
 113     uint16_t flags;  /* combination of NBD_REPLY_FLAG_* */
 114     uint16_t type;   /* NBD_REPLY_TYPE_* */
 115     uint64_t cookie; /* request handle */
 116     uint64_t offset; /* request offset */
 117     uint64_t length; /* length of payload */
 118 } QEMU_PACKED NBDExtendedReplyChunk;
 119
 120 typedef union NBDReply {
 121     NBDSimpleReply simple;
 122     NBDStructuredReplyChunk structured;
 123     NBDExtendedReplyChunk extended;
 124     struct {
 125         /*
 126          * @magic and @cookie fields have the same offset and size in all
 127          * forms of replies, so let them be accessible without ".simple.",
 128          * ".structured.", or ".extended." specifications.
 129          */
 130         uint32_t magic;
 131         uint32_t _skip;
 132         uint64_t cookie;
 133     };
 134 } NBDReply;
 135 QEMU_BUILD_BUG_ON(offsetof(NBDReply, simple.cookie) !=
 136                   offsetof(NBDReply, cookie));
 137 QEMU_BUILD_BUG_ON(offsetof(NBDReply, structured.cookie) !=
 138                   offsetof(NBDReply, cookie));
 139 QEMU_BUILD_BUG_ON(offsetof(NBDReply, extended.cookie) !=
 140                   offsetof(NBDReply, cookie));
 141
 142 /* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */
 143 typedef struct NBDStructuredReadData {
 144     /* header's .length >= 9 */
 145     uint64_t offset;
 146     /* At least one byte of data payload follows, calculated from h.length */
 147 } QEMU_PACKED NBDStructuredReadData;
 148
 149 /* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */
 150 typedef struct NBDStructuredReadHole {
 151     /* header's length == 12 */
 152     uint64_t offset;
 153     uint32_t length;
 154 } QEMU_PACKED NBDStructuredReadHole;
 155
 156 /* Header of all NBD_REPLY_TYPE_ERROR* errors */
 157 typedef struct NBDStructuredError {
 158     /* header's length >= 6 */
 159     uint32_t error;
 160     uint16_t message_length;
 161 } QEMU_PACKED NBDStructuredError;
 162
 163 /* Header of NBD_REPLY_TYPE_BLOCK_STATUS */
 164 typedef struct NBDStructuredMeta {
 165     /* header's length >= 12 (at least one extent) */
 166     uint32_t context_id;
 167     /* NBDExtent32 extents[] follows, array length implied by header */
 168 } QEMU_PACKED NBDStructuredMeta;
 169
 170 /* Extent array element for NBD_REPLY_TYPE_BLOCK_STATUS */
 171 typedef struct NBDExtent32 {
 172     uint32_t length;
 173     uint32_t flags; /* NBD_STATE_* */
 174 } QEMU_PACKED NBDExtent32;
 175
 176 /* Header of NBD_REPLY_TYPE_BLOCK_STATUS_EXT */
 177 typedef struct NBDExtendedMeta {
 178     /* header's length >= 24 (at least one extent) */
 179     uint32_t context_id;
 180     uint32_t count; /* header length must be count * 16 + 8 */
 181     /* NBDExtent64 extents[count] follows */
 182 } QEMU_PACKED NBDExtendedMeta;
 183
 184 /* Extent array element for NBD_REPLY_TYPE_BLOCK_STATUS_EXT */
 185 typedef struct NBDExtent64 {
 186     uint64_t length;
 187     uint64_t flags; /* NBD_STATE_* */
 188 } QEMU_PACKED NBDExtent64;
 189
 190 /* Client payload for limiting NBD_CMD_BLOCK_STATUS reply */
 191 typedef struct NBDBlockStatusPayload {
 192     uint64_t effect_length;
 193     /* uint32_t ids[] follows, array length implied by header */
 194 } QEMU_PACKED NBDBlockStatusPayload;
 195
 196 /* Transmission (export) flags: sent from server to client during handshake,
 197    but describe what will happen during transmission */
 198 enum {
 199     NBD_FLAG_HAS_FLAGS_BIT          =  0, /* Flags are there */
 200     NBD_FLAG_READ_ONLY_BIT          =  1, /* Device is read-only */
 201     NBD_FLAG_SEND_FLUSH_BIT         =  2, /* Send FLUSH */
 202     NBD_FLAG_SEND_FUA_BIT           =  3, /* Send FUA (Force Unit Access) */
 203     NBD_FLAG_ROTATIONAL_BIT         =  4, /* Use elevator algorithm -
 204                                              rotational media */
 205     NBD_FLAG_SEND_TRIM_BIT          =  5, /* Send TRIM (discard) */
 206     NBD_FLAG_SEND_WRITE_ZEROES_BIT  =  6, /* Send WRITE_ZEROES */
 207     NBD_FLAG_SEND_DF_BIT            =  7, /* Send DF (Do not Fragment) */
 208     NBD_FLAG_CAN_MULTI_CONN_BIT     =  8, /* Multi-client cache consistent */
 209     NBD_FLAG_SEND_RESIZE_BIT        =  9, /* Send resize */
 210     NBD_FLAG_SEND_CACHE_BIT         = 10, /* Send CACHE (prefetch) */
 211     NBD_FLAG_SEND_FAST_ZERO_BIT     = 11, /* FAST_ZERO flag for WRITE_ZEROES */
 212     NBD_FLAG_BLOCK_STAT_PAYLOAD_BIT = 12, /* PAYLOAD flag for BLOCK_STATUS */
 213 };
 214
 215 #define NBD_FLAG_HAS_FLAGS          (1 << NBD_FLAG_HAS_FLAGS_BIT)
 216 #define NBD_FLAG_READ_ONLY          (1 << NBD_FLAG_READ_ONLY_BIT)
 217 #define NBD_FLAG_SEND_FLUSH         (1 << NBD_FLAG_SEND_FLUSH_BIT)
 218 #define NBD_FLAG_SEND_FUA           (1 << NBD_FLAG_SEND_FUA_BIT)
 219 #define NBD_FLAG_ROTATIONAL         (1 << NBD_FLAG_ROTATIONAL_BIT)
 220 #define NBD_FLAG_SEND_TRIM          (1 << NBD_FLAG_SEND_TRIM_BIT)
 221 #define NBD_FLAG_SEND_WRITE_ZEROES  (1 << NBD_FLAG_SEND_WRITE_ZEROES_BIT)
 222 #define NBD_FLAG_SEND_DF            (1 << NBD_FLAG_SEND_DF_BIT)
 223 #define NBD_FLAG_CAN_MULTI_CONN     (1 << NBD_FLAG_CAN_MULTI_CONN_BIT)
 224 #define NBD_FLAG_SEND_RESIZE        (1 << NBD_FLAG_SEND_RESIZE_BIT)
 225 #define NBD_FLAG_SEND_CACHE         (1 << NBD_FLAG_SEND_CACHE_BIT)
 226 #define NBD_FLAG_SEND_FAST_ZERO     (1 << NBD_FLAG_SEND_FAST_ZERO_BIT)
 227 #define NBD_FLAG_BLOCK_STAT_PAYLOAD (1 << NBD_FLAG_BLOCK_STAT_PAYLOAD_BIT)
 228
 229 /* New-style handshake (global) flags, sent from server to client, and
 230    control what will happen during handshake phase. */
 231 #define NBD_FLAG_FIXED_NEWSTYLE   (1 << 0) /* Fixed newstyle protocol. */
 232 #define NBD_FLAG_NO_ZEROES        (1 << 1) /* End handshake without zeroes. */
 233
 234 /* New-style client flags, sent from client to server to control what happens
 235    during handshake phase. */
 236 #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
 237 #define NBD_FLAG_C_NO_ZEROES      (1 << 1) /* End handshake without zeroes. */
 238
 239 /* Option requests. */
 240 #define NBD_OPT_EXPORT_NAME       (1)
 241 #define NBD_OPT_ABORT             (2)
 242 #define NBD_OPT_LIST              (3)
 243 /* #define NBD_OPT_PEEK_EXPORT    (4) not in use */
 244 #define NBD_OPT_STARTTLS          (5)
 245 #define NBD_OPT_INFO              (6)
 246 #define NBD_OPT_GO                (7)
 247 #define NBD_OPT_STRUCTURED_REPLY  (8)
 248 #define NBD_OPT_LIST_META_CONTEXT (9)
 249 #define NBD_OPT_SET_META_CONTEXT  (10)
 250 #define NBD_OPT_EXTENDED_HEADERS  (11)
 251
 252 /* Option reply types. */
 253 #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value))
 254
 255 #define NBD_REP_ACK             (1)    /* Data sending finished. */
 256 #define NBD_REP_SERVER          (2)    /* Export description. */
 257 #define NBD_REP_INFO            (3)    /* NBD_OPT_INFO/GO. */
 258 #define NBD_REP_META_CONTEXT    (4)    /* NBD_OPT_{LIST,SET}_META_CONTEXT */
 259
 260 #define NBD_REP_ERR_UNSUP           NBD_REP_ERR(1)  /* Unknown option */
 261 #define NBD_REP_ERR_POLICY          NBD_REP_ERR(2)  /* Server denied */
 262 #define NBD_REP_ERR_INVALID         NBD_REP_ERR(3)  /* Invalid length */
 263 #define NBD_REP_ERR_PLATFORM        NBD_REP_ERR(4)  /* Not compiled in */
 264 #define NBD_REP_ERR_TLS_REQD        NBD_REP_ERR(5)  /* TLS required */
 265 #define NBD_REP_ERR_UNKNOWN         NBD_REP_ERR(6)  /* Export unknown */
 266 #define NBD_REP_ERR_SHUTDOWN        NBD_REP_ERR(7)  /* Server shutting down */
 267 #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8)  /* Need INFO_BLOCK_SIZE */
 268 #define NBD_REP_ERR_TOO_BIG         NBD_REP_ERR(9)  /* Payload size overflow */
 269 #define NBD_REP_ERR_EXT_HEADER_REQD NBD_REP_ERR(10) /* Need extended headers */
 270
 271 /* Info types, used during NBD_REP_INFO */
 272 #define NBD_INFO_EXPORT         0
 273 #define NBD_INFO_NAME           1
 274 #define NBD_INFO_DESCRIPTION    2
 275 #define NBD_INFO_BLOCK_SIZE     3
 276
 277 /* Request flags, sent from client to server during transmission phase */
 278 #define NBD_CMD_FLAG_FUA         (1 << 0) /* 'force unit access' during write */
 279 #define NBD_CMD_FLAG_NO_HOLE     (1 << 1) /* don't punch hole on zero run */
 280 #define NBD_CMD_FLAG_DF          (1 << 2) /* don't fragment structured read */
 281 #define NBD_CMD_FLAG_REQ_ONE     (1 << 3) \
 282     /* only one extent in BLOCK_STATUS reply chunk */
 283 #define NBD_CMD_FLAG_FAST_ZERO   (1 << 4) /* fail if WRITE_ZEROES is not fast */
 284 #define NBD_CMD_FLAG_PAYLOAD_LEN (1 << 5) \
 285     /* length describes payload, not effect; only with ext header */
 286
 287 /* Supported request types */
 288 enum {
 289     NBD_CMD_READ = 0,
 290     NBD_CMD_WRITE = 1,
 291     NBD_CMD_DISC = 2,
 292     NBD_CMD_FLUSH = 3,
 293     NBD_CMD_TRIM = 4,
 294     NBD_CMD_CACHE = 5,
 295     NBD_CMD_WRITE_ZEROES = 6,
 296     NBD_CMD_BLOCK_STATUS = 7,
 297 };
 298
 299 #define NBD_DEFAULT_PORT        10809
 300
 301 /* Maximum size of a single READ/WRITE data buffer */
 302 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
 303
 304 /*
 305  * Maximum size of a protocol string (export name, metadata context name,
 306  * etc.).  Use malloc rather than stack allocation for storage of a
 307  * string.
 308  */
 309 #define NBD_MAX_STRING_SIZE 4096
 310
 311 /* Two types of request structures, a given client will only use 1 */
 312 #define NBD_REQUEST_MAGIC           0x25609513
 313 #define NBD_EXTENDED_REQUEST_MAGIC  0x21e41c71
 314
 315 /*
 316  * Three types of reply structures, but what a client expects depends
 317  * on NBD_OPT_STRUCTURED_REPLY and NBD_OPT_EXTENDED_HEADERS.
 318  */
 319 #define NBD_SIMPLE_REPLY_MAGIC      0x67446698
 320 #define NBD_STRUCTURED_REPLY_MAGIC  0x668e33ef
 321 #define NBD_EXTENDED_REPLY_MAGIC    0x6e8a278c
 322
 323 /* Chunk reply flags (for structured and extended replies) */
 324 #define NBD_REPLY_FLAG_DONE          (1 << 0) /* This reply-chunk is last */
 325
 326 /* Chunk reply types */
 327 #define NBD_REPLY_ERR(value)         ((1 << 15) | (value))
 328
 329 #define NBD_REPLY_TYPE_NONE              0
 330 #define NBD_REPLY_TYPE_OFFSET_DATA       1
 331 #define NBD_REPLY_TYPE_OFFSET_HOLE       2
 332 #define NBD_REPLY_TYPE_BLOCK_STATUS      5
 333 #define NBD_REPLY_TYPE_BLOCK_STATUS_EXT  6
 334 #define NBD_REPLY_TYPE_ERROR             NBD_REPLY_ERR(1)
 335 #define NBD_REPLY_TYPE_ERROR_OFFSET      NBD_REPLY_ERR(2)
 336
 337 /* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */
 338 #define NBD_STATE_HOLE (1 << 0)
 339 #define NBD_STATE_ZERO (1 << 1)
 340
 341 /* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */
 342 #define NBD_STATE_DIRTY (1 << 0)
 343
 344 /* No flags needed for qemu:allocation-depth in NBD_REPLY_TYPE_BLOCK_STATUS */
 345
 346 static inline bool nbd_reply_type_is_error(int type)
 347 {
 348     return type & (1 << 15);
 349 }
 350
 351 /* NBD errors are based on errno numbers, so there is a 1:1 mapping,
 352  * but only a limited set of errno values is specified in the protocol.
 353  * Everything else is squashed to EINVAL.
 354  */
 355 #define NBD_SUCCESS    0
 356 #define NBD_EPERM      1
 357 #define NBD_EIO        5
 358 #define NBD_ENOMEM     12
 359 #define NBD_EINVAL     22
 360 #define NBD_ENOSPC     28
 361 #define NBD_EOVERFLOW  75
 362 #define NBD_ENOTSUP    95
 363 #define NBD_ESHUTDOWN  108
 364
 365 /* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */
 366 typedef struct NBDExportInfo {
 367     /* Set by client before nbd_receive_negotiate() */
 368     bool request_sizes;
 369     char *x_dirty_bitmap;
 370
 371     /* Set by client before nbd_receive_negotiate(), or by server results
 372      * during nbd_receive_export_list() */
 373     char *name; /* must be non-NULL */
 374
 375     /* In-out fields, set by client before nbd_receive_negotiate() and
 376      * updated by server results during nbd_receive_negotiate() */
 377     NBDMode mode; /* input maximum mode tolerated; output actual mode chosen */
 378     bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */
 379
 380     /* Set by server results during nbd_receive_negotiate() and
 381      * nbd_receive_export_list() */
 382     uint64_t size;
 383     uint16_t flags;
 384     uint32_t min_block;
 385     uint32_t opt_block;
 386     uint32_t max_block;
 387
 388     uint32_t context_id;
 389
 390     /* Set by server results during nbd_receive_export_list() */
 391     char *description;
 392     int n_contexts;
 393     char **contexts;
 394 } NBDExportInfo;
 395
 396 int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
 397                           const char *hostname, QIOChannel **outioc,
 398                           NBDExportInfo *info, Error **errp);
 399 void nbd_free_export_list(NBDExportInfo *info, int count);
 400 int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
 401                             const char *hostname, NBDExportInfo **info,
 402                             Error **errp);
 403 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
 404              Error **errp);
 405 int nbd_send_request(QIOChannel *ioc, NBDRequest *request);
 406 int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
 407                                    NBDReply *reply, NBDMode mode,
 408                                    Error **errp);
 409 int nbd_client(int fd);
 410 int nbd_disconnect(int fd);
 411 int nbd_errno_to_system_errno(int err);
 412
 413 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk);
 414
 415 AioContext *nbd_export_aio_context(NBDExport *exp);
 416 NBDExport *nbd_export_find(const char *name);
 417
 418 void nbd_client_new(QIOChannelSocket *sioc,
 419                     uint32_t handshake_max_secs,
 420                     QCryptoTLSCreds *tlscreds,
 421                     const char *tlsauthz,
 422                     void (*close_fn)(NBDClient *, bool),
 423                     void *owner);
 424 void *nbd_client_owner(NBDClient *client);
 425 void nbd_client_get(NBDClient *client);
 426 void nbd_client_put(NBDClient *client);
 427
 428 void nbd_server_is_qemu_nbd(int max_connections);
 429 bool nbd_server_is_running(void);
 430 int nbd_server_max_connections(void);
 431 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
 432                       const char *tls_authz, uint32_t max_connections,
 433                       Error **errp);
 434 void nbd_server_start_options(NbdServerOptions *arg, Error **errp);
 435
 436 /* nbd_read
 437  * Reads @size bytes from @ioc. Returns 0 on success.
 438  */
 439 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
 440                            const char *desc, Error **errp)
 441 {
 442     ERRP_GUARD();
 443     int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
 444
 445     if (ret < 0) {
 446         if (desc) {
 447             error_prepend(errp, "Failed to read %s: ", desc);
 448         }
 449         return ret;
 450     }
 451
 452     return 0;
 453 }
 454
 455 #define DEF_NBD_READ_N(bits)                                            \
 456 static inline int nbd_read##bits(QIOChannel *ioc,                       \
 457                                  uint##bits##_t *val,                   \
 458                                  const char *desc, Error **errp)        \
 459 {                                                                       \
 460     int ret = nbd_read(ioc, val, sizeof(*val), desc, errp);             \
 461     if (ret < 0) {                                                      \
 462         return ret;                                                     \
 463     }                                                                   \
 464     *val = be##bits##_to_cpu(*val);                                     \
 465     return 0;                                                           \
 466 }
 467
 468 DEF_NBD_READ_N(16) /* Defines nbd_read16(). */
 469 DEF_NBD_READ_N(32) /* Defines nbd_read32(). */
 470 DEF_NBD_READ_N(64) /* Defines nbd_read64(). */
 471
 472 #undef DEF_NBD_READ_N
 473
 474 static inline bool nbd_reply_is_simple(NBDReply *reply)
 475 {
 476     return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
 477 }
 478
 479 static inline bool nbd_reply_is_structured(NBDReply *reply)
 480 {
 481     return reply->magic == NBD_STRUCTURED_REPLY_MAGIC;
 482 }
 483
 484 const char *nbd_reply_type_lookup(uint16_t type);
 485 const char *nbd_opt_lookup(uint32_t opt);
 486 const char *nbd_rep_lookup(uint32_t rep);
 487 const char *nbd_info_lookup(uint16_t info);
 488 const char *nbd_cmd_lookup(uint16_t info);
 489 const char *nbd_err_lookup(int err);
 490 const char *nbd_mode_lookup(NBDMode mode);
 491
 492 /* nbd/client-connection.c */
 493 void nbd_client_connection_enable_retry(NBDClientConnection *conn);
 494
 495 NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr,
 496                                                bool do_negotiation,
 497                                                const char *export_name,
 498                                                const char *x_dirty_bitmap,
 499                                                QCryptoTLSCreds *tlscreds,
 500                                                const char *tlshostname);
 501 void nbd_client_connection_release(NBDClientConnection *conn);
 502
 503 QIOChannel *coroutine_fn
 504 nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info,
 505                             bool blocking, Error **errp);
 506
 507 void nbd_co_establish_connection_cancel(NBDClientConnection *conn);
 508
 509 #endif