LXR qemu/include/block/nbd.h

   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
  30struct NBDOption {
  31    uint64_t magic; /* NBD_OPTS_MAGIC */
  32    uint32_t option; /* NBD_OPT_* */
  33    uint32_t length;
  34} QEMU_PACKED;
  35typedef struct NBDOption NBDOption;
  36
  37struct 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;
  43typedef struct NBDOptionReply NBDOptionReply;
  44
  45typedef 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 */
  56struct 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};
  63typedef struct NBDRequest NBDRequest;
  64
  65typedef 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 */
  72typedef 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
  80typedef 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 */
  95typedef 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 */
 102typedef 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 */
 109typedef 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 */
 116typedef 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 */
 123typedef 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 */
 130enum {
 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 */
 210enum {
 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
 257static 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 */
 276struct 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};
 305typedef struct NBDExportInfo NBDExportInfo;
 306
 307int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
 308                          const char *hostname, QIOChannel **outioc,
 309                          NBDExportInfo *info, Error **errp);
 310void nbd_free_export_list(NBDExportInfo *info, int count);
 311int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
 312                            const char *hostname, NBDExportInfo **info,
 313                            Error **errp);
 314int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
 315             Error **errp);
 316int nbd_send_request(QIOChannel *ioc, NBDRequest *request);
 317int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
 318                                   NBDReply *reply, Error **errp);
 319int nbd_client(int fd);
 320int nbd_disconnect(int fd);
 321int nbd_errno_to_system_errno(int err);
 322
 323typedef struct NBDExport NBDExport;
 324typedef struct NBDClient NBDClient;
 325
 326NBDExport *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);
 331void nbd_export_close(NBDExport *exp);
 332void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
 333void nbd_export_get(NBDExport *exp);
 334void nbd_export_put(NBDExport *exp);
 335
 336BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
 337
 338NBDExport *nbd_export_find(const char *name);
 339void nbd_export_close_all(void);
 340
 341void nbd_client_new(QIOChannelSocket *sioc,
 342                    QCryptoTLSCreds *tlscreds,
 343                    const char *tlsauthz,
 344                    void (*close_fn)(NBDClient *, bool));
 345void nbd_client_get(NBDClient *client);
 346void nbd_client_put(NBDClient *client);
 347
 348void 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 */
 354static 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)                                            \
 370static 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
 381DEF_NBD_READ_N(16) /* Defines nbd_read16(). */
 382DEF_NBD_READ_N(32) /* Defines nbd_read32(). */
 383DEF_NBD_READ_N(64) /* Defines nbd_read64(). */
 384
 385#undef DEF_NBD_READ_N
 386
 387static inline bool nbd_reply_is_simple(NBDReply *reply)
 388{
 389    return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
 390}
 391
 392static inline bool nbd_reply_is_structured(NBDReply *reply)
 393{
 394    return reply->magic == NBD_STRUCTURED_REPLY_MAGIC;
 395}
 396
 397const char *nbd_reply_type_lookup(uint16_t type);
 398const char *nbd_opt_lookup(uint32_t opt);
 399const char *nbd_rep_lookup(uint32_t rep);
 400const char *nbd_info_lookup(uint16_t info);
 401const char *nbd_cmd_lookup(uint16_t info);
 402const char *nbd_err_lookup(int err);
 403
 404#endif
 405