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