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 */
 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 */
 196enum {
 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
 243static 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 */
 262struct 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};
 291typedef struct NBDExportInfo NBDExportInfo;
 292
 293int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
 294                          const char *hostname, QIOChannel **outioc,
 295                          NBDExportInfo *info, Error **errp);
 296void nbd_free_export_list(NBDExportInfo *info, int count);
 297int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
 298                            const char *hostname, NBDExportInfo **info,
 299                            Error **errp);
 300int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
 301             Error **errp);
 302int nbd_send_request(QIOChannel *ioc, NBDRequest *request);
 303int coroutine_fn nbd_receive_reply(BlockDriverState *bs, QIOChannel *ioc,
 304                                   NBDReply *reply, Error **errp);
 305int nbd_client(int fd);
 306int nbd_disconnect(int fd);
 307int nbd_errno_to_system_errno(int err);
 308
 309typedef struct NBDExport NBDExport;
 310typedef struct NBDClient NBDClient;
 311
 312NBDExport *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);
 317void nbd_export_close(NBDExport *exp);
 318void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
 319void nbd_export_get(NBDExport *exp);
 320void nbd_export_put(NBDExport *exp);
 321
 322BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
 323
 324NBDExport *nbd_export_find(const char *name);
 325void nbd_export_close_all(void);
 326
 327void nbd_client_new(QIOChannelSocket *sioc,
 328                    QCryptoTLSCreds *tlscreds,
 329                    const char *tlsauthz,
 330                    void (*close_fn)(NBDClient *, bool));
 331void nbd_client_get(NBDClient *client);
 332void nbd_client_put(NBDClient *client);
 333
 334void nbd_server_start(SocketAddress *addr, const char *tls_creds,
 335                      const char *tls_authz, Error **errp);
 336
 337/* nbd_read
 338 * Reads @size bytes from @ioc. Returns 0 on success.
 339 */
 340static 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)                                            \
 356static 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
 367DEF_NBD_READ_N(16) /* Defines nbd_read16(). */
 368DEF_NBD_READ_N(32) /* Defines nbd_read32(). */
 369DEF_NBD_READ_N(64) /* Defines nbd_read64(). */
 370
 371#undef DEF_NBD_READ_N
 372
 373static inline bool nbd_reply_is_simple(NBDReply *reply)
 374{
 375    return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
 376}
 377
 378static inline bool nbd_reply_is_structured(NBDReply *reply)
 379{
 380    return reply->magic == NBD_STRUCTURED_REPLY_MAGIC;
 381}
 382
 383const char *nbd_reply_type_lookup(uint16_t type);
 384const char *nbd_opt_lookup(uint32_t opt);
 385const char *nbd_rep_lookup(uint32_t rep);
 386const char *nbd_info_lookup(uint16_t info);
 387const char *nbd_cmd_lookup(uint16_t info);
 388const char *nbd_err_lookup(int err);
 389
 390#endif
 391