1 /* 2 * Copyright (C) 2016-2019 Red Hat, Inc. 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 "qapi/qapi-types-block.h" 24 #include "io/channel-socket.h" 25 #include "crypto/tlscreds.h" 26 #include "qapi/error.h" 27 28 /* Handshake phase structs - this struct is passed on the wire */ 29 30 struct NBDOption { 31 uint64_t magic; /* NBD_OPTS_MAGIC */ 32 uint32_t option; /* NBD_OPT_* */ 33 uint32_t length; 34 } QEMU_PACKED; 35 typedef struct NBDOption NBDOption; 36 37 struct NBDOptionReply { 38 uint64_t magic; /* NBD_REP_MAGIC */ 39 uint32_t option; /* NBD_OPT_* */ 40 uint32_t type; /* NBD_REP_* */ 41 uint32_t length; 42 } QEMU_PACKED; 43 typedef struct NBDOptionReply NBDOptionReply; 44 45 typedef struct NBDOptionReplyMetaContext { 46 NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */ 47 uint32_t context_id; 48 /* meta context name follows */ 49 } QEMU_PACKED NBDOptionReplyMetaContext; 50 51 /* Transmission phase structs 52 * 53 * Note: these are _NOT_ the same as the network representation of an NBD 54 * request and reply! 55 */ 56 struct NBDRequest { 57 uint64_t handle; 58 uint64_t from; 59 uint32_t len; 60 uint16_t flags; /* NBD_CMD_FLAG_* */ 61 uint16_t type; /* NBD_CMD_* */ 62 }; 63 typedef struct NBDRequest NBDRequest; 64 65 typedef struct NBDSimpleReply { 66 uint32_t magic; /* NBD_SIMPLE_REPLY_MAGIC */ 67 uint32_t error; 68 uint64_t handle; 69 } QEMU_PACKED NBDSimpleReply; 70 71 /* Header of all structured replies */ 72 typedef struct NBDStructuredReplyChunk { 73 uint32_t magic; /* NBD_STRUCTURED_REPLY_MAGIC */ 74 uint16_t flags; /* combination of NBD_REPLY_FLAG_* */ 75 uint16_t type; /* NBD_REPLY_TYPE_* */ 76 uint64_t handle; /* request handle */ 77 uint32_t length; /* length of payload */ 78 } QEMU_PACKED NBDStructuredReplyChunk; 79 80 typedef union NBDReply { 81 NBDSimpleReply simple; 82 NBDStructuredReplyChunk structured; 83 struct { 84 /* @magic and @handle fields have the same offset and size both in 85 * simple reply and structured reply chunk, so let them be accessible 86 * without ".simple." or ".structured." specification 87 */ 88 uint32_t magic; 89 uint32_t _skip; 90 uint64_t handle; 91 } QEMU_PACKED; 92 } NBDReply; 93 94 /* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */ 95 typedef struct NBDStructuredReadData { 96 NBDStructuredReplyChunk h; /* h.length >= 9 */ 97 uint64_t offset; 98 /* At least one byte of data payload follows, calculated from h.length */ 99 } QEMU_PACKED NBDStructuredReadData; 100 101 /* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */ 102 typedef struct NBDStructuredReadHole { 103 NBDStructuredReplyChunk h; /* h.length == 12 */ 104 uint64_t offset; 105 uint32_t length; 106 } QEMU_PACKED NBDStructuredReadHole; 107 108 /* Header of all NBD_REPLY_TYPE_ERROR* errors */ 109 typedef struct NBDStructuredError { 110 NBDStructuredReplyChunk h; /* h.length >= 6 */ 111 uint32_t error; 112 uint16_t message_length; 113 } QEMU_PACKED NBDStructuredError; 114 115 /* Header of NBD_REPLY_TYPE_BLOCK_STATUS */ 116 typedef struct NBDStructuredMeta { 117 NBDStructuredReplyChunk h; /* h.length >= 12 (at least one extent) */ 118 uint32_t context_id; 119 /* extents follows */ 120 } QEMU_PACKED NBDStructuredMeta; 121 122 /* Extent chunk for NBD_REPLY_TYPE_BLOCK_STATUS */ 123 typedef struct NBDExtent { 124 uint32_t length; 125 uint32_t flags; /* NBD_STATE_* */ 126 } QEMU_PACKED NBDExtent; 127 128 /* Transmission (export) flags: sent from server to client during handshake, 129 but describe what will happen during transmission */ 130 enum { 131 NBD_FLAG_HAS_FLAGS_BIT = 0, /* Flags are there */ 132 NBD_FLAG_READ_ONLY_BIT = 1, /* Device is read-only */ 133 NBD_FLAG_SEND_FLUSH_BIT = 2, /* Send FLUSH */ 134 NBD_FLAG_SEND_FUA_BIT = 3, /* Send FUA (Force Unit Access) */ 135 NBD_FLAG_ROTATIONAL_BIT = 4, /* Use elevator algorithm - 136 rotational media */ 137 NBD_FLAG_SEND_TRIM_BIT = 5, /* Send TRIM (discard) */ 138 NBD_FLAG_SEND_WRITE_ZEROES_BIT = 6, /* Send WRITE_ZEROES */ 139 NBD_FLAG_SEND_DF_BIT = 7, /* Send DF (Do not Fragment) */ 140 NBD_FLAG_CAN_MULTI_CONN_BIT = 8, /* Multi-client cache consistent */ 141 NBD_FLAG_SEND_RESIZE_BIT = 9, /* Send resize */ 142 NBD_FLAG_SEND_CACHE_BIT = 10, /* Send CACHE (prefetch) */ 143 }; 144 145 #define NBD_FLAG_HAS_FLAGS (1 << NBD_FLAG_HAS_FLAGS_BIT) 146 #define NBD_FLAG_READ_ONLY (1 << NBD_FLAG_READ_ONLY_BIT) 147 #define NBD_FLAG_SEND_FLUSH (1 << NBD_FLAG_SEND_FLUSH_BIT) 148 #define NBD_FLAG_SEND_FUA (1 << NBD_FLAG_SEND_FUA_BIT) 149 #define NBD_FLAG_ROTATIONAL (1 << NBD_FLAG_ROTATIONAL_BIT) 150 #define NBD_FLAG_SEND_TRIM (1 << NBD_FLAG_SEND_TRIM_BIT) 151 #define NBD_FLAG_SEND_WRITE_ZEROES (1 << NBD_FLAG_SEND_WRITE_ZEROES_BIT) 152 #define NBD_FLAG_SEND_DF (1 << NBD_FLAG_SEND_DF_BIT) 153 #define NBD_FLAG_CAN_MULTI_CONN (1 << NBD_FLAG_CAN_MULTI_CONN_BIT) 154 #define NBD_FLAG_SEND_RESIZE (1 << NBD_FLAG_SEND_RESIZE_BIT) 155 #define NBD_FLAG_SEND_CACHE (1 << NBD_FLAG_SEND_CACHE_BIT) 156 157 /* New-style handshake (global) flags, sent from server to client, and 158 control what will happen during handshake phase. */ 159 #define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ 160 #define NBD_FLAG_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ 161 162 /* New-style client flags, sent from client to server to control what happens 163 during handshake phase. */ 164 #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ 165 #define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ 166 167 /* Option requests. */ 168 #define NBD_OPT_EXPORT_NAME (1) 169 #define NBD_OPT_ABORT (2) 170 #define NBD_OPT_LIST (3) 171 /* #define NBD_OPT_PEEK_EXPORT (4) not in use */ 172 #define NBD_OPT_STARTTLS (5) 173 #define NBD_OPT_INFO (6) 174 #define NBD_OPT_GO (7) 175 #define NBD_OPT_STRUCTURED_REPLY (8) 176 #define NBD_OPT_LIST_META_CONTEXT (9) 177 #define NBD_OPT_SET_META_CONTEXT (10) 178 179 /* Option reply types. */ 180 #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value)) 181 182 #define NBD_REP_ACK (1) /* Data sending finished. */ 183 #define NBD_REP_SERVER (2) /* Export description. */ 184 #define NBD_REP_INFO (3) /* NBD_OPT_INFO/GO. */ 185 #define NBD_REP_META_CONTEXT (4) /* NBD_OPT_{LIST,SET}_META_CONTEXT */ 186 187 #define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */ 188 #define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */ 189 #define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */ 190 #define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */ 191 #define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */ 192 #define NBD_REP_ERR_UNKNOWN NBD_REP_ERR(6) /* Export unknown */ 193 #define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */ 194 #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8) /* Need INFO_BLOCK_SIZE */ 195 196 /* Info types, used during NBD_REP_INFO */ 197 #define NBD_INFO_EXPORT 0 198 #define NBD_INFO_NAME 1 199 #define NBD_INFO_DESCRIPTION 2 200 #define NBD_INFO_BLOCK_SIZE 3 201 202 /* Request flags, sent from client to server during transmission phase */ 203 #define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */ 204 #define NBD_CMD_FLAG_NO_HOLE (1 << 1) /* don't punch hole on zero run */ 205 #define NBD_CMD_FLAG_DF (1 << 2) /* don't fragment structured read */ 206 #define NBD_CMD_FLAG_REQ_ONE (1 << 3) /* only one extent in BLOCK_STATUS 207 * reply chunk */ 208 209 /* Supported request types */ 210 enum { 211 NBD_CMD_READ = 0, 212 NBD_CMD_WRITE = 1, 213 NBD_CMD_DISC = 2, 214 NBD_CMD_FLUSH = 3, 215 NBD_CMD_TRIM = 4, 216 NBD_CMD_CACHE = 5, 217 NBD_CMD_WRITE_ZEROES = 6, 218 NBD_CMD_BLOCK_STATUS = 7, 219 }; 220 221 #define NBD_DEFAULT_PORT 10809 222 223 /* Maximum size of a single READ/WRITE data buffer */ 224 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024) 225 226 /* Maximum size of an export name. The NBD spec requires 256 and 227 * suggests that servers support up to 4096, but we stick to only the 228 * required size so that we can stack-allocate the names, and because 229 * going larger would require an audit of more code to make sure we 230 * aren't overflowing some other buffer. */ 231 #define NBD_MAX_NAME_SIZE 256 232 233 /* Two types of reply structures */ 234 #define NBD_SIMPLE_REPLY_MAGIC 0x67446698 235 #define NBD_STRUCTURED_REPLY_MAGIC 0x668e33ef 236 237 /* Structured reply flags */ 238 #define NBD_REPLY_FLAG_DONE (1 << 0) /* This reply-chunk is last */ 239 240 /* Structured reply types */ 241 #define NBD_REPLY_ERR(value) ((1 << 15) | (value)) 242 243 #define NBD_REPLY_TYPE_NONE 0 244 #define NBD_REPLY_TYPE_OFFSET_DATA 1 245 #define NBD_REPLY_TYPE_OFFSET_HOLE 2 246 #define NBD_REPLY_TYPE_BLOCK_STATUS 5 247 #define NBD_REPLY_TYPE_ERROR NBD_REPLY_ERR(1) 248 #define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_ERR(2) 249 250 /* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */ 251 #define NBD_STATE_HOLE (1 << 0) 252 #define NBD_STATE_ZERO (1 << 1) 253 254 /* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */ 255 #define NBD_STATE_DIRTY (1 << 0) 256 257 static inline bool nbd_reply_type_is_error(int type) 258 { 259 return type & (1 << 15); 260 } 261 262 /* NBD errors are based on errno numbers, so there is a 1:1 mapping, 263 * but only a limited set of errno values is specified in the protocol. 264 * Everything else is squashed to EINVAL. 265 */ 266 #define NBD_SUCCESS 0 267 #define NBD_EPERM 1 268 #define NBD_EIO 5 269 #define NBD_ENOMEM 12 270 #define NBD_EINVAL 22 271 #define NBD_ENOSPC 28 272 #define NBD_EOVERFLOW 75 273 #define NBD_ESHUTDOWN 108 274 275 /* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */ 276 struct NBDExportInfo { 277 /* Set by client before nbd_receive_negotiate() */ 278 bool request_sizes; 279 char *x_dirty_bitmap; 280 281 /* Set by client before nbd_receive_negotiate(), or by server results 282 * during nbd_receive_export_list() */ 283 char *name; /* must be non-NULL */ 284 285 /* In-out fields, set by client before nbd_receive_negotiate() and 286 * updated by server results during nbd_receive_negotiate() */ 287 bool structured_reply; 288 bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */ 289 290 /* Set by server results during nbd_receive_negotiate() and 291 * nbd_receive_export_list() */ 292 uint64_t size; 293 uint16_t flags; 294 uint32_t min_block; 295 uint32_t opt_block; 296 uint32_t max_block; 297 298 uint32_t context_id; 299 300 /* Set by server results during nbd_receive_export_list() */ 301 char *description; 302 int n_contexts; 303 char **contexts; 304 }; 305 typedef struct NBDExportInfo NBDExportInfo; 306 307 int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 308 const char *hostname, QIOChannel **outioc, 309 NBDExportInfo *info, Error **errp); 310 void nbd_free_export_list(NBDExportInfo *info, int count); 311 int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 312 const char *hostname, NBDExportInfo **info, 313 Error **errp); 314 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, 315 Error **errp); 316 int nbd_send_request(QIOChannel *ioc, NBDRequest *request); 317 int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc, 318 NBDReply *reply, Error **errp); 319 int nbd_client(int fd); 320 int nbd_disconnect(int fd); 321 int nbd_errno_to_system_errno(int err); 322 323 typedef struct NBDExport NBDExport; 324 typedef struct NBDClient NBDClient; 325 326 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, 327 uint64_t size, const char *name, const char *desc, 328 const char *bitmap, uint16_t nbdflags, 329 void (*close)(NBDExport *), bool writethrough, 330 BlockBackend *on_eject_blk, Error **errp); 331 void nbd_export_close(NBDExport *exp); 332 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp); 333 void nbd_export_get(NBDExport *exp); 334 void nbd_export_put(NBDExport *exp); 335 336 BlockBackend *nbd_export_get_blockdev(NBDExport *exp); 337 338 NBDExport *nbd_export_find(const char *name); 339 void nbd_export_close_all(void); 340 341 void nbd_client_new(QIOChannelSocket *sioc, 342 QCryptoTLSCreds *tlscreds, 343 const char *tlsauthz, 344 void (*close_fn)(NBDClient *, bool)); 345 void nbd_client_get(NBDClient *client); 346 void nbd_client_put(NBDClient *client); 347 348 void nbd_server_start(SocketAddress *addr, const char *tls_creds, 349 const char *tls_authz, Error **errp); 350 351 /* nbd_read 352 * Reads @size bytes from @ioc. Returns 0 on success. 353 */ 354 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size, 355 const char *desc, Error **errp) 356 { 357 int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0; 358 359 if (ret < 0) { 360 if (desc) { 361 error_prepend(errp, "Failed to read %s: ", desc); 362 } 363 return -1; 364 } 365 366 return 0; 367 } 368 369 #define DEF_NBD_READ_N(bits) \ 370 static inline int nbd_read##bits(QIOChannel *ioc, \ 371 uint##bits##_t *val, \ 372 const char *desc, Error **errp) \ 373 { \ 374 if (nbd_read(ioc, val, sizeof(*val), desc, errp) < 0) { \ 375 return -1; \ 376 } \ 377 *val = be##bits##_to_cpu(*val); \ 378 return 0; \ 379 } 380 381 DEF_NBD_READ_N(16) /* Defines nbd_read16(). */ 382 DEF_NBD_READ_N(32) /* Defines nbd_read32(). */ 383 DEF_NBD_READ_N(64) /* Defines nbd_read64(). */ 384 385 #undef DEF_NBD_READ_N 386 387 static inline bool nbd_reply_is_simple(NBDReply *reply) 388 { 389 return reply->magic == NBD_SIMPLE_REPLY_MAGIC; 390 } 391 392 static inline bool nbd_reply_is_structured(NBDReply *reply) 393 { 394 return reply->magic == NBD_STRUCTURED_REPLY_MAGIC; 395 } 396 397 const char *nbd_reply_type_lookup(uint16_t type); 398 const char *nbd_opt_lookup(uint32_t opt); 399 const char *nbd_rep_lookup(uint32_t rep); 400 const char *nbd_info_lookup(uint16_t info); 401 const char *nbd_cmd_lookup(uint16_t info); 402 const char *nbd_err_lookup(int err); 403 404 #endif 405