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 #define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */ 131 #define NBD_FLAG_READ_ONLY (1 << 1) /* Device is read-only */ 132 #define NBD_FLAG_SEND_FLUSH (1 << 2) /* Send FLUSH */ 133 #define NBD_FLAG_SEND_FUA (1 << 3) /* Send FUA (Force Unit Access) */ 134 #define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm - 135 rotational media */ 136 #define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */ 137 #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */ 138 #define NBD_FLAG_SEND_DF (1 << 7) /* Send DF (Do not Fragment) */ 139 #define NBD_FLAG_CAN_MULTI_CONN (1 << 8) /* Multi-client cache consistent */ 140 #define NBD_FLAG_SEND_RESIZE (1 << 9) /* Send resize */ 141 #define NBD_FLAG_SEND_CACHE (1 << 10) /* Send CACHE (prefetch) */ 142 143 /* New-style handshake (global) flags, sent from server to client, and 144 control what will happen during handshake phase. */ 145 #define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ 146 #define NBD_FLAG_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ 147 148 /* New-style client flags, sent from client to server to control what happens 149 during handshake phase. */ 150 #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ 151 #define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ 152 153 /* Option requests. */ 154 #define NBD_OPT_EXPORT_NAME (1) 155 #define NBD_OPT_ABORT (2) 156 #define NBD_OPT_LIST (3) 157 /* #define NBD_OPT_PEEK_EXPORT (4) not in use */ 158 #define NBD_OPT_STARTTLS (5) 159 #define NBD_OPT_INFO (6) 160 #define NBD_OPT_GO (7) 161 #define NBD_OPT_STRUCTURED_REPLY (8) 162 #define NBD_OPT_LIST_META_CONTEXT (9) 163 #define NBD_OPT_SET_META_CONTEXT (10) 164 165 /* Option reply types. */ 166 #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value)) 167 168 #define NBD_REP_ACK (1) /* Data sending finished. */ 169 #define NBD_REP_SERVER (2) /* Export description. */ 170 #define NBD_REP_INFO (3) /* NBD_OPT_INFO/GO. */ 171 #define NBD_REP_META_CONTEXT (4) /* NBD_OPT_{LIST,SET}_META_CONTEXT */ 172 173 #define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */ 174 #define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */ 175 #define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */ 176 #define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */ 177 #define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */ 178 #define NBD_REP_ERR_UNKNOWN NBD_REP_ERR(6) /* Export unknown */ 179 #define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */ 180 #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8) /* Need INFO_BLOCK_SIZE */ 181 182 /* Info types, used during NBD_REP_INFO */ 183 #define NBD_INFO_EXPORT 0 184 #define NBD_INFO_NAME 1 185 #define NBD_INFO_DESCRIPTION 2 186 #define NBD_INFO_BLOCK_SIZE 3 187 188 /* Request flags, sent from client to server during transmission phase */ 189 #define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */ 190 #define NBD_CMD_FLAG_NO_HOLE (1 << 1) /* don't punch hole on zero run */ 191 #define NBD_CMD_FLAG_DF (1 << 2) /* don't fragment structured read */ 192 #define NBD_CMD_FLAG_REQ_ONE (1 << 3) /* only one extent in BLOCK_STATUS 193 * reply chunk */ 194 195 /* Supported request types */ 196 enum { 197 NBD_CMD_READ = 0, 198 NBD_CMD_WRITE = 1, 199 NBD_CMD_DISC = 2, 200 NBD_CMD_FLUSH = 3, 201 NBD_CMD_TRIM = 4, 202 NBD_CMD_CACHE = 5, 203 NBD_CMD_WRITE_ZEROES = 6, 204 NBD_CMD_BLOCK_STATUS = 7, 205 }; 206 207 #define NBD_DEFAULT_PORT 10809 208 209 /* Maximum size of a single READ/WRITE data buffer */ 210 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024) 211 212 /* Maximum size of an export name. The NBD spec requires 256 and 213 * suggests that servers support up to 4096, but we stick to only the 214 * required size so that we can stack-allocate the names, and because 215 * going larger would require an audit of more code to make sure we 216 * aren't overflowing some other buffer. */ 217 #define NBD_MAX_NAME_SIZE 256 218 219 /* Two types of reply structures */ 220 #define NBD_SIMPLE_REPLY_MAGIC 0x67446698 221 #define NBD_STRUCTURED_REPLY_MAGIC 0x668e33ef 222 223 /* Structured reply flags */ 224 #define NBD_REPLY_FLAG_DONE (1 << 0) /* This reply-chunk is last */ 225 226 /* Structured reply types */ 227 #define NBD_REPLY_ERR(value) ((1 << 15) | (value)) 228 229 #define NBD_REPLY_TYPE_NONE 0 230 #define NBD_REPLY_TYPE_OFFSET_DATA 1 231 #define NBD_REPLY_TYPE_OFFSET_HOLE 2 232 #define NBD_REPLY_TYPE_BLOCK_STATUS 5 233 #define NBD_REPLY_TYPE_ERROR NBD_REPLY_ERR(1) 234 #define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_ERR(2) 235 236 /* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */ 237 #define NBD_STATE_HOLE (1 << 0) 238 #define NBD_STATE_ZERO (1 << 1) 239 240 /* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */ 241 #define NBD_STATE_DIRTY (1 << 0) 242 243 static inline bool nbd_reply_type_is_error(int type) 244 { 245 return type & (1 << 15); 246 } 247 248 /* NBD errors are based on errno numbers, so there is a 1:1 mapping, 249 * but only a limited set of errno values is specified in the protocol. 250 * Everything else is squashed to EINVAL. 251 */ 252 #define NBD_SUCCESS 0 253 #define NBD_EPERM 1 254 #define NBD_EIO 5 255 #define NBD_ENOMEM 12 256 #define NBD_EINVAL 22 257 #define NBD_ENOSPC 28 258 #define NBD_EOVERFLOW 75 259 #define NBD_ESHUTDOWN 108 260 261 /* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */ 262 struct NBDExportInfo { 263 /* Set by client before nbd_receive_negotiate() */ 264 bool request_sizes; 265 char *x_dirty_bitmap; 266 267 /* Set by client before nbd_receive_negotiate(), or by server results 268 * during nbd_receive_export_list() */ 269 char *name; /* must be non-NULL */ 270 271 /* In-out fields, set by client before nbd_receive_negotiate() and 272 * updated by server results during nbd_receive_negotiate() */ 273 bool structured_reply; 274 bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */ 275 276 /* Set by server results during nbd_receive_negotiate() and 277 * nbd_receive_export_list() */ 278 uint64_t size; 279 uint16_t flags; 280 uint32_t min_block; 281 uint32_t opt_block; 282 uint32_t max_block; 283 284 uint32_t context_id; 285 286 /* Set by server results during nbd_receive_export_list() */ 287 char *description; 288 int n_contexts; 289 char **contexts; 290 }; 291 typedef struct NBDExportInfo NBDExportInfo; 292 293 int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 294 const char *hostname, QIOChannel **outioc, 295 NBDExportInfo *info, Error **errp); 296 void nbd_free_export_list(NBDExportInfo *info, int count); 297 int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 298 const char *hostname, NBDExportInfo **info, 299 Error **errp); 300 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, 301 Error **errp); 302 int nbd_send_request(QIOChannel *ioc, NBDRequest *request); 303 int coroutine_fn nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, 304 Error **errp); 305 int nbd_client(int fd); 306 int nbd_disconnect(int fd); 307 int nbd_errno_to_system_errno(int err); 308 309 typedef struct NBDExport NBDExport; 310 typedef struct NBDClient NBDClient; 311 312 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, 313 uint64_t size, const char *name, const char *desc, 314 const char *bitmap, uint16_t nbdflags, 315 void (*close)(NBDExport *), bool writethrough, 316 BlockBackend *on_eject_blk, Error **errp); 317 void nbd_export_close(NBDExport *exp); 318 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp); 319 void nbd_export_get(NBDExport *exp); 320 void nbd_export_put(NBDExport *exp); 321 322 BlockBackend *nbd_export_get_blockdev(NBDExport *exp); 323 324 NBDExport *nbd_export_find(const char *name); 325 void nbd_export_close_all(void); 326 327 void nbd_client_new(QIOChannelSocket *sioc, 328 QCryptoTLSCreds *tlscreds, 329 const char *tlsaclname, 330 void (*close_fn)(NBDClient *, bool)); 331 void nbd_client_get(NBDClient *client); 332 void nbd_client_put(NBDClient *client); 333 334 void nbd_server_start(SocketAddress *addr, const char *tls_creds, 335 Error **errp); 336 337 /* nbd_read 338 * Reads @size bytes from @ioc. Returns 0 on success. 339 */ 340 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size, 341 const char *desc, Error **errp) 342 { 343 int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0; 344 345 if (ret < 0) { 346 if (desc) { 347 error_prepend(errp, "Failed to read %s: ", desc); 348 } 349 return -1; 350 } 351 352 return 0; 353 } 354 355 #define DEF_NBD_READ_N(bits) \ 356 static inline int nbd_read##bits(QIOChannel *ioc, \ 357 uint##bits##_t *val, \ 358 const char *desc, Error **errp) \ 359 { \ 360 if (nbd_read(ioc, val, sizeof(*val), desc, errp) < 0) { \ 361 return -1; \ 362 } \ 363 *val = be##bits##_to_cpu(*val); \ 364 return 0; \ 365 } 366 367 DEF_NBD_READ_N(16) /* Defines nbd_read16(). */ 368 DEF_NBD_READ_N(32) /* Defines nbd_read32(). */ 369 DEF_NBD_READ_N(64) /* Defines nbd_read64(). */ 370 371 #undef DEF_NBD_READ_N 372 373 static inline bool nbd_reply_is_simple(NBDReply *reply) 374 { 375 return reply->magic == NBD_SIMPLE_REPLY_MAGIC; 376 } 377 378 static inline bool nbd_reply_is_structured(NBDReply *reply) 379 { 380 return reply->magic == NBD_STRUCTURED_REPLY_MAGIC; 381 } 382 383 const char *nbd_reply_type_lookup(uint16_t type); 384 const char *nbd_opt_lookup(uint32_t opt); 385 const char *nbd_rep_lookup(uint32_t rep); 386 const char *nbd_info_lookup(uint16_t info); 387 const char *nbd_cmd_lookup(uint16_t info); 388 const char *nbd_err_lookup(int err); 389 390 #endif 391