1 /* 2 * Copyright (C) 2016-2017 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 27 /* Handshake phase structs - this struct is passed on the wire */ 28 29 struct NBDOption { 30 uint64_t magic; /* NBD_OPTS_MAGIC */ 31 uint32_t option; /* NBD_OPT_* */ 32 uint32_t length; 33 } QEMU_PACKED; 34 typedef struct NBDOption NBDOption; 35 36 struct NBDOptionReply { 37 uint64_t magic; /* NBD_REP_MAGIC */ 38 uint32_t option; /* NBD_OPT_* */ 39 uint32_t type; /* NBD_REP_* */ 40 uint32_t length; 41 } QEMU_PACKED; 42 typedef struct NBDOptionReply NBDOptionReply; 43 44 typedef struct NBDOptionReplyMetaContext { 45 NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */ 46 uint32_t context_id; 47 /* meta context name follows */ 48 } QEMU_PACKED NBDOptionReplyMetaContext; 49 50 /* Transmission phase structs 51 * 52 * Note: these are _NOT_ the same as the network representation of an NBD 53 * request and reply! 54 */ 55 struct NBDRequest { 56 uint64_t handle; 57 uint64_t from; 58 uint32_t len; 59 uint16_t flags; /* NBD_CMD_FLAG_* */ 60 uint16_t type; /* NBD_CMD_* */ 61 }; 62 typedef struct NBDRequest NBDRequest; 63 64 typedef struct NBDSimpleReply { 65 uint32_t magic; /* NBD_SIMPLE_REPLY_MAGIC */ 66 uint32_t error; 67 uint64_t handle; 68 } QEMU_PACKED NBDSimpleReply; 69 70 /* Header of all structured replies */ 71 typedef struct NBDStructuredReplyChunk { 72 uint32_t magic; /* NBD_STRUCTURED_REPLY_MAGIC */ 73 uint16_t flags; /* combination of NBD_REPLY_FLAG_* */ 74 uint16_t type; /* NBD_REPLY_TYPE_* */ 75 uint64_t handle; /* request handle */ 76 uint32_t length; /* length of payload */ 77 } QEMU_PACKED NBDStructuredReplyChunk; 78 79 typedef union NBDReply { 80 NBDSimpleReply simple; 81 NBDStructuredReplyChunk structured; 82 struct { 83 /* @magic and @handle fields have the same offset and size both in 84 * simple reply and structured reply chunk, so let them be accessible 85 * without ".simple." or ".structured." specification 86 */ 87 uint32_t magic; 88 uint32_t _skip; 89 uint64_t handle; 90 } QEMU_PACKED; 91 } NBDReply; 92 93 /* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */ 94 typedef struct NBDStructuredReadData { 95 NBDStructuredReplyChunk h; /* h.length >= 9 */ 96 uint64_t offset; 97 /* At least one byte of data payload follows, calculated from h.length */ 98 } QEMU_PACKED NBDStructuredReadData; 99 100 /* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */ 101 typedef struct NBDStructuredReadHole { 102 NBDStructuredReplyChunk h; /* h.length == 12 */ 103 uint64_t offset; 104 uint32_t length; 105 } QEMU_PACKED NBDStructuredReadHole; 106 107 /* Header of all NBD_REPLY_TYPE_ERROR* errors */ 108 typedef struct NBDStructuredError { 109 NBDStructuredReplyChunk h; /* h.length >= 6 */ 110 uint32_t error; 111 uint16_t message_length; 112 } QEMU_PACKED NBDStructuredError; 113 114 /* Header of NBD_REPLY_TYPE_BLOCK_STATUS */ 115 typedef struct NBDStructuredMeta { 116 NBDStructuredReplyChunk h; /* h.length >= 12 (at least one extent) */ 117 uint32_t context_id; 118 /* extents follows */ 119 } QEMU_PACKED NBDStructuredMeta; 120 121 /* Extent chunk for NBD_REPLY_TYPE_BLOCK_STATUS */ 122 typedef struct NBDExtent { 123 uint32_t length; 124 uint32_t flags; /* NBD_STATE_* */ 125 } QEMU_PACKED NBDExtent; 126 127 /* Transmission (export) flags: sent from server to client during handshake, 128 but describe what will happen during transmission */ 129 #define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */ 130 #define NBD_FLAG_READ_ONLY (1 << 1) /* Device is read-only */ 131 #define NBD_FLAG_SEND_FLUSH (1 << 2) /* Send FLUSH */ 132 #define NBD_FLAG_SEND_FUA (1 << 3) /* Send FUA (Force Unit Access) */ 133 #define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm - 134 rotational media */ 135 #define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */ 136 #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */ 137 #define NBD_FLAG_SEND_DF (1 << 7) /* Send DF (Do not Fragment) */ 138 #define NBD_FLAG_CAN_MULTI_CONN (1 << 8) /* Multi-client cache consistent */ 139 #define NBD_FLAG_SEND_RESIZE (1 << 9) /* Send resize */ 140 #define NBD_FLAG_SEND_CACHE (1 << 10) /* Send CACHE (prefetch) */ 141 142 /* New-style handshake (global) flags, sent from server to client, and 143 control what will happen during handshake phase. */ 144 #define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ 145 #define NBD_FLAG_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ 146 147 /* New-style client flags, sent from client to server to control what happens 148 during handshake phase. */ 149 #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ 150 #define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ 151 152 /* Option requests. */ 153 #define NBD_OPT_EXPORT_NAME (1) 154 #define NBD_OPT_ABORT (2) 155 #define NBD_OPT_LIST (3) 156 /* #define NBD_OPT_PEEK_EXPORT (4) not in use */ 157 #define NBD_OPT_STARTTLS (5) 158 #define NBD_OPT_INFO (6) 159 #define NBD_OPT_GO (7) 160 #define NBD_OPT_STRUCTURED_REPLY (8) 161 #define NBD_OPT_LIST_META_CONTEXT (9) 162 #define NBD_OPT_SET_META_CONTEXT (10) 163 164 /* Option reply types. */ 165 #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value)) 166 167 #define NBD_REP_ACK (1) /* Data sending finished. */ 168 #define NBD_REP_SERVER (2) /* Export description. */ 169 #define NBD_REP_INFO (3) /* NBD_OPT_INFO/GO. */ 170 #define NBD_REP_META_CONTEXT (4) /* NBD_OPT_{LIST,SET}_META_CONTEXT */ 171 172 #define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */ 173 #define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */ 174 #define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */ 175 #define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */ 176 #define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */ 177 #define NBD_REP_ERR_UNKNOWN NBD_REP_ERR(6) /* Export unknown */ 178 #define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */ 179 #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8) /* Need INFO_BLOCK_SIZE */ 180 181 /* Info types, used during NBD_REP_INFO */ 182 #define NBD_INFO_EXPORT 0 183 #define NBD_INFO_NAME 1 184 #define NBD_INFO_DESCRIPTION 2 185 #define NBD_INFO_BLOCK_SIZE 3 186 187 /* Request flags, sent from client to server during transmission phase */ 188 #define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */ 189 #define NBD_CMD_FLAG_NO_HOLE (1 << 1) /* don't punch hole on zero run */ 190 #define NBD_CMD_FLAG_DF (1 << 2) /* don't fragment structured read */ 191 #define NBD_CMD_FLAG_REQ_ONE (1 << 3) /* only one extent in BLOCK_STATUS 192 * reply chunk */ 193 194 /* Supported request types */ 195 enum { 196 NBD_CMD_READ = 0, 197 NBD_CMD_WRITE = 1, 198 NBD_CMD_DISC = 2, 199 NBD_CMD_FLUSH = 3, 200 NBD_CMD_TRIM = 4, 201 NBD_CMD_CACHE = 5, 202 NBD_CMD_WRITE_ZEROES = 6, 203 NBD_CMD_BLOCK_STATUS = 7, 204 }; 205 206 #define NBD_DEFAULT_PORT 10809 207 208 /* Maximum size of a single READ/WRITE data buffer */ 209 #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024) 210 211 /* Maximum size of an export name. The NBD spec requires 256 and 212 * suggests that servers support up to 4096, but we stick to only the 213 * required size so that we can stack-allocate the names, and because 214 * going larger would require an audit of more code to make sure we 215 * aren't overflowing some other buffer. */ 216 #define NBD_MAX_NAME_SIZE 256 217 218 /* Two types of reply structures */ 219 #define NBD_SIMPLE_REPLY_MAGIC 0x67446698 220 #define NBD_STRUCTURED_REPLY_MAGIC 0x668e33ef 221 222 /* Structured reply flags */ 223 #define NBD_REPLY_FLAG_DONE (1 << 0) /* This reply-chunk is last */ 224 225 /* Structured reply types */ 226 #define NBD_REPLY_ERR(value) ((1 << 15) | (value)) 227 228 #define NBD_REPLY_TYPE_NONE 0 229 #define NBD_REPLY_TYPE_OFFSET_DATA 1 230 #define NBD_REPLY_TYPE_OFFSET_HOLE 2 231 #define NBD_REPLY_TYPE_BLOCK_STATUS 5 232 #define NBD_REPLY_TYPE_ERROR NBD_REPLY_ERR(1) 233 #define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_ERR(2) 234 235 /* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */ 236 #define NBD_STATE_HOLE (1 << 0) 237 #define NBD_STATE_ZERO (1 << 1) 238 239 /* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */ 240 #define NBD_STATE_DIRTY (1 << 0) 241 242 static inline bool nbd_reply_type_is_error(int type) 243 { 244 return type & (1 << 15); 245 } 246 247 /* NBD errors are based on errno numbers, so there is a 1:1 mapping, 248 * but only a limited set of errno values is specified in the protocol. 249 * Everything else is squashed to EINVAL. 250 */ 251 #define NBD_SUCCESS 0 252 #define NBD_EPERM 1 253 #define NBD_EIO 5 254 #define NBD_ENOMEM 12 255 #define NBD_EINVAL 22 256 #define NBD_ENOSPC 28 257 #define NBD_EOVERFLOW 75 258 #define NBD_ESHUTDOWN 108 259 260 /* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */ 261 struct NBDExportInfo { 262 /* Set by client before nbd_receive_negotiate() */ 263 bool request_sizes; 264 char *x_dirty_bitmap; 265 266 /* In-out fields, set by client before nbd_receive_negotiate() and 267 * updated by server results during nbd_receive_negotiate() */ 268 bool structured_reply; 269 bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */ 270 271 /* Set by server results during nbd_receive_negotiate() */ 272 uint64_t size; 273 uint16_t flags; 274 uint32_t min_block; 275 uint32_t opt_block; 276 uint32_t max_block; 277 278 uint32_t meta_base_allocation_id; 279 }; 280 typedef struct NBDExportInfo NBDExportInfo; 281 282 int nbd_receive_negotiate(QIOChannel *ioc, const char *name, 283 QCryptoTLSCreds *tlscreds, const char *hostname, 284 QIOChannel **outioc, NBDExportInfo *info, 285 Error **errp); 286 int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, 287 Error **errp); 288 int nbd_send_request(QIOChannel *ioc, NBDRequest *request); 289 int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp); 290 int nbd_client(int fd); 291 int nbd_disconnect(int fd); 292 int nbd_errno_to_system_errno(int err); 293 294 typedef struct NBDExport NBDExport; 295 typedef struct NBDClient NBDClient; 296 297 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, 298 uint16_t nbdflags, void (*close)(NBDExport *), 299 bool writethrough, BlockBackend *on_eject_blk, 300 Error **errp); 301 void nbd_export_close(NBDExport *exp); 302 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp); 303 void nbd_export_get(NBDExport *exp); 304 void nbd_export_put(NBDExport *exp); 305 306 BlockBackend *nbd_export_get_blockdev(NBDExport *exp); 307 308 NBDExport *nbd_export_find(const char *name); 309 void nbd_export_set_name(NBDExport *exp, const char *name); 310 void nbd_export_set_description(NBDExport *exp, const char *description); 311 void nbd_export_close_all(void); 312 313 void nbd_client_new(QIOChannelSocket *sioc, 314 QCryptoTLSCreds *tlscreds, 315 const char *tlsaclname, 316 void (*close_fn)(NBDClient *, bool)); 317 void nbd_client_get(NBDClient *client); 318 void nbd_client_put(NBDClient *client); 319 320 void nbd_server_start(SocketAddress *addr, const char *tls_creds, 321 Error **errp); 322 323 void nbd_export_bitmap(NBDExport *exp, const char *bitmap, 324 const char *bitmap_export_name, Error **errp); 325 326 /* nbd_read 327 * Reads @size bytes from @ioc. Returns 0 on success. 328 */ 329 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size, 330 Error **errp) 331 { 332 return qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0; 333 } 334 335 static inline bool nbd_reply_is_simple(NBDReply *reply) 336 { 337 return reply->magic == NBD_SIMPLE_REPLY_MAGIC; 338 } 339 340 static inline bool nbd_reply_is_structured(NBDReply *reply) 341 { 342 return reply->magic == NBD_STRUCTURED_REPLY_MAGIC; 343 } 344 345 const char *nbd_reply_type_lookup(uint16_t type); 346 347 #endif 348