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 494