qemu/block/nbd.c
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   1/*
   2 * QEMU Block driver for  NBD
   3 *
   4 * Copyright (C) 2008 Bull S.A.S.
   5 *     Author: Laurent Vivier <Laurent.Vivier@bull.net>
   6 *
   7 * Some parts:
   8 *    Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
   9 *
  10 * Permission is hereby granted, free of charge, to any person obtaining a copy
  11 * of this software and associated documentation files (the "Software"), to deal
  12 * in the Software without restriction, including without limitation the rights
  13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14 * copies of the Software, and to permit persons to whom the Software is
  15 * furnished to do so, subject to the following conditions:
  16 *
  17 * The above copyright notice and this permission notice shall be included in
  18 * all copies or substantial portions of the Software.
  19 *
  20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  26 * THE SOFTWARE.
  27 */
  28
  29#include "qemu/osdep.h"
  30#include "nbd-client.h"
  31#include "block/qdict.h"
  32#include "qapi/error.h"
  33#include "qemu/uri.h"
  34#include "block/block_int.h"
  35#include "qemu/module.h"
  36#include "qemu/option.h"
  37#include "qapi/qapi-visit-sockets.h"
  38#include "qapi/qobject-input-visitor.h"
  39#include "qapi/qobject-output-visitor.h"
  40#include "qapi/qmp/qdict.h"
  41#include "qapi/qmp/qstring.h"
  42#include "qemu/cutils.h"
  43
  44#define EN_OPTSTR ":exportname="
  45
  46typedef struct BDRVNBDState {
  47    NBDClientSession client;
  48
  49    /* For nbd_refresh_filename() */
  50    SocketAddress *saddr;
  51    char *export, *tlscredsid;
  52} BDRVNBDState;
  53
  54static int nbd_parse_uri(const char *filename, QDict *options)
  55{
  56    URI *uri;
  57    const char *p;
  58    QueryParams *qp = NULL;
  59    int ret = 0;
  60    bool is_unix;
  61
  62    uri = uri_parse(filename);
  63    if (!uri) {
  64        return -EINVAL;
  65    }
  66
  67    /* transport */
  68    if (!g_strcmp0(uri->scheme, "nbd")) {
  69        is_unix = false;
  70    } else if (!g_strcmp0(uri->scheme, "nbd+tcp")) {
  71        is_unix = false;
  72    } else if (!g_strcmp0(uri->scheme, "nbd+unix")) {
  73        is_unix = true;
  74    } else {
  75        ret = -EINVAL;
  76        goto out;
  77    }
  78
  79    p = uri->path ? uri->path : "/";
  80    p += strspn(p, "/");
  81    if (p[0]) {
  82        qdict_put_str(options, "export", p);
  83    }
  84
  85    qp = query_params_parse(uri->query);
  86    if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
  87        ret = -EINVAL;
  88        goto out;
  89    }
  90
  91    if (is_unix) {
  92        /* nbd+unix:///export?socket=path */
  93        if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
  94            ret = -EINVAL;
  95            goto out;
  96        }
  97        qdict_put_str(options, "server.type", "unix");
  98        qdict_put_str(options, "server.path", qp->p[0].value);
  99    } else {
 100        QString *host;
 101        char *port_str;
 102
 103        /* nbd[+tcp]://host[:port]/export */
 104        if (!uri->server) {
 105            ret = -EINVAL;
 106            goto out;
 107        }
 108
 109        /* strip braces from literal IPv6 address */
 110        if (uri->server[0] == '[') {
 111            host = qstring_from_substr(uri->server, 1,
 112                                       strlen(uri->server) - 1);
 113        } else {
 114            host = qstring_from_str(uri->server);
 115        }
 116
 117        qdict_put_str(options, "server.type", "inet");
 118        qdict_put(options, "server.host", host);
 119
 120        port_str = g_strdup_printf("%d", uri->port ?: NBD_DEFAULT_PORT);
 121        qdict_put_str(options, "server.port", port_str);
 122        g_free(port_str);
 123    }
 124
 125out:
 126    if (qp) {
 127        query_params_free(qp);
 128    }
 129    uri_free(uri);
 130    return ret;
 131}
 132
 133static bool nbd_has_filename_options_conflict(QDict *options, Error **errp)
 134{
 135    const QDictEntry *e;
 136
 137    for (e = qdict_first(options); e; e = qdict_next(options, e)) {
 138        if (!strcmp(e->key, "host") ||
 139            !strcmp(e->key, "port") ||
 140            !strcmp(e->key, "path") ||
 141            !strcmp(e->key, "export") ||
 142            strstart(e->key, "server.", NULL))
 143        {
 144            error_setg(errp, "Option '%s' cannot be used with a file name",
 145                       e->key);
 146            return true;
 147        }
 148    }
 149
 150    return false;
 151}
 152
 153static void nbd_parse_filename(const char *filename, QDict *options,
 154                               Error **errp)
 155{
 156    char *file;
 157    char *export_name;
 158    const char *host_spec;
 159    const char *unixpath;
 160
 161    if (nbd_has_filename_options_conflict(options, errp)) {
 162        return;
 163    }
 164
 165    if (strstr(filename, "://")) {
 166        int ret = nbd_parse_uri(filename, options);
 167        if (ret < 0) {
 168            error_setg(errp, "No valid URL specified");
 169        }
 170        return;
 171    }
 172
 173    file = g_strdup(filename);
 174
 175    export_name = strstr(file, EN_OPTSTR);
 176    if (export_name) {
 177        if (export_name[strlen(EN_OPTSTR)] == 0) {
 178            goto out;
 179        }
 180        export_name[0] = 0; /* truncate 'file' */
 181        export_name += strlen(EN_OPTSTR);
 182
 183        qdict_put_str(options, "export", export_name);
 184    }
 185
 186    /* extract the host_spec - fail if it's not nbd:... */
 187    if (!strstart(file, "nbd:", &host_spec)) {
 188        error_setg(errp, "File name string for NBD must start with 'nbd:'");
 189        goto out;
 190    }
 191
 192    if (!*host_spec) {
 193        goto out;
 194    }
 195
 196    /* are we a UNIX or TCP socket? */
 197    if (strstart(host_spec, "unix:", &unixpath)) {
 198        qdict_put_str(options, "server.type", "unix");
 199        qdict_put_str(options, "server.path", unixpath);
 200    } else {
 201        InetSocketAddress *addr = g_new(InetSocketAddress, 1);
 202
 203        if (inet_parse(addr, host_spec, errp)) {
 204            goto out_inet;
 205        }
 206
 207        qdict_put_str(options, "server.type", "inet");
 208        qdict_put_str(options, "server.host", addr->host);
 209        qdict_put_str(options, "server.port", addr->port);
 210    out_inet:
 211        qapi_free_InetSocketAddress(addr);
 212    }
 213
 214out:
 215    g_free(file);
 216}
 217
 218static bool nbd_process_legacy_socket_options(QDict *output_options,
 219                                              QemuOpts *legacy_opts,
 220                                              Error **errp)
 221{
 222    const char *path = qemu_opt_get(legacy_opts, "path");
 223    const char *host = qemu_opt_get(legacy_opts, "host");
 224    const char *port = qemu_opt_get(legacy_opts, "port");
 225    const QDictEntry *e;
 226
 227    if (!path && !host && !port) {
 228        return true;
 229    }
 230
 231    for (e = qdict_first(output_options); e; e = qdict_next(output_options, e))
 232    {
 233        if (strstart(e->key, "server.", NULL)) {
 234            error_setg(errp, "Cannot use 'server' and path/host/port at the "
 235                       "same time");
 236            return false;
 237        }
 238    }
 239
 240    if (path && host) {
 241        error_setg(errp, "path and host may not be used at the same time");
 242        return false;
 243    } else if (path) {
 244        if (port) {
 245            error_setg(errp, "port may not be used without host");
 246            return false;
 247        }
 248
 249        qdict_put_str(output_options, "server.type", "unix");
 250        qdict_put_str(output_options, "server.path", path);
 251    } else if (host) {
 252        qdict_put_str(output_options, "server.type", "inet");
 253        qdict_put_str(output_options, "server.host", host);
 254        qdict_put_str(output_options, "server.port",
 255                      port ?: stringify(NBD_DEFAULT_PORT));
 256    }
 257
 258    return true;
 259}
 260
 261static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
 262                                 Error **errp)
 263{
 264    SocketAddress *saddr = NULL;
 265    QDict *addr = NULL;
 266    Visitor *iv = NULL;
 267    Error *local_err = NULL;
 268
 269    qdict_extract_subqdict(options, &addr, "server.");
 270    if (!qdict_size(addr)) {
 271        error_setg(errp, "NBD server address missing");
 272        goto done;
 273    }
 274
 275    iv = qobject_input_visitor_new_flat_confused(addr, errp);
 276    if (!iv) {
 277        goto done;
 278    }
 279
 280    visit_type_SocketAddress(iv, NULL, &saddr, &local_err);
 281    if (local_err) {
 282        error_propagate(errp, local_err);
 283        goto done;
 284    }
 285
 286done:
 287    qobject_unref(addr);
 288    visit_free(iv);
 289    return saddr;
 290}
 291
 292NBDClientSession *nbd_get_client_session(BlockDriverState *bs)
 293{
 294    BDRVNBDState *s = bs->opaque;
 295    return &s->client;
 296}
 297
 298static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
 299                                                  Error **errp)
 300{
 301    QIOChannelSocket *sioc;
 302    Error *local_err = NULL;
 303
 304    sioc = qio_channel_socket_new();
 305    qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
 306
 307    qio_channel_socket_connect_sync(sioc,
 308                                    saddr,
 309                                    &local_err);
 310    if (local_err) {
 311        object_unref(OBJECT(sioc));
 312        error_propagate(errp, local_err);
 313        return NULL;
 314    }
 315
 316    qio_channel_set_delay(QIO_CHANNEL(sioc), false);
 317
 318    return sioc;
 319}
 320
 321
 322static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 323{
 324    Object *obj;
 325    QCryptoTLSCreds *creds;
 326
 327    obj = object_resolve_path_component(
 328        object_get_objects_root(), id);
 329    if (!obj) {
 330        error_setg(errp, "No TLS credentials with id '%s'",
 331                   id);
 332        return NULL;
 333    }
 334    creds = (QCryptoTLSCreds *)
 335        object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 336    if (!creds) {
 337        error_setg(errp, "Object with id '%s' is not TLS credentials",
 338                   id);
 339        return NULL;
 340    }
 341
 342    if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
 343        error_setg(errp,
 344                   "Expecting TLS credentials with a client endpoint");
 345        return NULL;
 346    }
 347    object_ref(obj);
 348    return creds;
 349}
 350
 351
 352static QemuOptsList nbd_runtime_opts = {
 353    .name = "nbd",
 354    .head = QTAILQ_HEAD_INITIALIZER(nbd_runtime_opts.head),
 355    .desc = {
 356        {
 357            .name = "host",
 358            .type = QEMU_OPT_STRING,
 359            .help = "TCP host to connect to",
 360        },
 361        {
 362            .name = "port",
 363            .type = QEMU_OPT_STRING,
 364            .help = "TCP port to connect to",
 365        },
 366        {
 367            .name = "path",
 368            .type = QEMU_OPT_STRING,
 369            .help = "Unix socket path to connect to",
 370        },
 371        {
 372            .name = "export",
 373            .type = QEMU_OPT_STRING,
 374            .help = "Name of the NBD export to open",
 375        },
 376        {
 377            .name = "tls-creds",
 378            .type = QEMU_OPT_STRING,
 379            .help = "ID of the TLS credentials to use",
 380        },
 381        {
 382            .name = "x-dirty-bitmap",
 383            .type = QEMU_OPT_STRING,
 384            .help = "experimental: expose named dirty bitmap in place of "
 385                    "block status",
 386        },
 387        { /* end of list */ }
 388    },
 389};
 390
 391static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 392                    Error **errp)
 393{
 394    BDRVNBDState *s = bs->opaque;
 395    QemuOpts *opts = NULL;
 396    Error *local_err = NULL;
 397    QIOChannelSocket *sioc = NULL;
 398    QCryptoTLSCreds *tlscreds = NULL;
 399    const char *hostname = NULL;
 400    int ret = -EINVAL;
 401
 402    opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
 403    qemu_opts_absorb_qdict(opts, options, &local_err);
 404    if (local_err) {
 405        error_propagate(errp, local_err);
 406        goto error;
 407    }
 408
 409    /* Translate @host, @port, and @path to a SocketAddress */
 410    if (!nbd_process_legacy_socket_options(options, opts, errp)) {
 411        goto error;
 412    }
 413
 414    /* Pop the config into our state object. Exit if invalid. */
 415    s->saddr = nbd_config(s, options, errp);
 416    if (!s->saddr) {
 417        goto error;
 418    }
 419
 420    s->export = g_strdup(qemu_opt_get(opts, "export"));
 421
 422    s->tlscredsid = g_strdup(qemu_opt_get(opts, "tls-creds"));
 423    if (s->tlscredsid) {
 424        tlscreds = nbd_get_tls_creds(s->tlscredsid, errp);
 425        if (!tlscreds) {
 426            goto error;
 427        }
 428
 429        /* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */
 430        if (s->saddr->type != SOCKET_ADDRESS_TYPE_INET) {
 431            error_setg(errp, "TLS only supported over IP sockets");
 432            goto error;
 433        }
 434        hostname = s->saddr->u.inet.host;
 435    }
 436
 437    /* establish TCP connection, return error if it fails
 438     * TODO: Configurable retry-until-timeout behaviour.
 439     */
 440    sioc = nbd_establish_connection(s->saddr, errp);
 441    if (!sioc) {
 442        ret = -ECONNREFUSED;
 443        goto error;
 444    }
 445
 446    /* NBD handshake */
 447    ret = nbd_client_init(bs, sioc, s->export, tlscreds, hostname,
 448                          qemu_opt_get(opts, "x-dirty-bitmap"), errp);
 449 error:
 450    if (sioc) {
 451        object_unref(OBJECT(sioc));
 452    }
 453    if (tlscreds) {
 454        object_unref(OBJECT(tlscreds));
 455    }
 456    if (ret < 0) {
 457        qapi_free_SocketAddress(s->saddr);
 458        g_free(s->export);
 459        g_free(s->tlscredsid);
 460    }
 461    qemu_opts_del(opts);
 462    return ret;
 463}
 464
 465static int nbd_co_flush(BlockDriverState *bs)
 466{
 467    return nbd_client_co_flush(bs);
 468}
 469
 470static void nbd_refresh_limits(BlockDriverState *bs, Error **errp)
 471{
 472    NBDClientSession *s = nbd_get_client_session(bs);
 473    uint32_t min = s->info.min_block;
 474    uint32_t max = MIN_NON_ZERO(NBD_MAX_BUFFER_SIZE, s->info.max_block);
 475
 476    bs->bl.request_alignment = min ? min : BDRV_SECTOR_SIZE;
 477    bs->bl.max_pdiscard = max;
 478    bs->bl.max_pwrite_zeroes = max;
 479    bs->bl.max_transfer = max;
 480
 481    if (s->info.opt_block &&
 482        s->info.opt_block > bs->bl.opt_transfer) {
 483        bs->bl.opt_transfer = s->info.opt_block;
 484    }
 485}
 486
 487static void nbd_close(BlockDriverState *bs)
 488{
 489    BDRVNBDState *s = bs->opaque;
 490
 491    nbd_client_close(bs);
 492
 493    qapi_free_SocketAddress(s->saddr);
 494    g_free(s->export);
 495    g_free(s->tlscredsid);
 496}
 497
 498static int64_t nbd_getlength(BlockDriverState *bs)
 499{
 500    BDRVNBDState *s = bs->opaque;
 501
 502    return s->client.info.size;
 503}
 504
 505static void nbd_detach_aio_context(BlockDriverState *bs)
 506{
 507    nbd_client_detach_aio_context(bs);
 508}
 509
 510static void nbd_attach_aio_context(BlockDriverState *bs,
 511                                   AioContext *new_context)
 512{
 513    nbd_client_attach_aio_context(bs, new_context);
 514}
 515
 516static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
 517{
 518    BDRVNBDState *s = bs->opaque;
 519    QDict *opts = qdict_new();
 520    QObject *saddr_qdict;
 521    Visitor *ov;
 522    const char *host = NULL, *port = NULL, *path = NULL;
 523
 524    if (s->saddr->type == SOCKET_ADDRESS_TYPE_INET) {
 525        const InetSocketAddress *inet = &s->saddr->u.inet;
 526        if (!inet->has_ipv4 && !inet->has_ipv6 && !inet->has_to) {
 527            host = inet->host;
 528            port = inet->port;
 529        }
 530    } else if (s->saddr->type == SOCKET_ADDRESS_TYPE_UNIX) {
 531        path = s->saddr->u.q_unix.path;
 532    } /* else can't represent as pseudo-filename */
 533
 534    qdict_put_str(opts, "driver", "nbd");
 535
 536    if (path && s->export) {
 537        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 538                 "nbd+unix:///%s?socket=%s", s->export, path);
 539    } else if (path && !s->export) {
 540        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 541                 "nbd+unix://?socket=%s", path);
 542    } else if (host && s->export) {
 543        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 544                 "nbd://%s:%s/%s", host, port, s->export);
 545    } else if (host && !s->export) {
 546        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 547                 "nbd://%s:%s", host, port);
 548    }
 549
 550    ov = qobject_output_visitor_new(&saddr_qdict);
 551    visit_type_SocketAddress(ov, NULL, &s->saddr, &error_abort);
 552    visit_complete(ov, &saddr_qdict);
 553    visit_free(ov);
 554    qdict_put_obj(opts, "server", saddr_qdict);
 555
 556    if (s->export) {
 557        qdict_put_str(opts, "export", s->export);
 558    }
 559    if (s->tlscredsid) {
 560        qdict_put_str(opts, "tls-creds", s->tlscredsid);
 561    }
 562
 563    qdict_flatten(opts);
 564    bs->full_open_options = opts;
 565}
 566
 567static BlockDriver bdrv_nbd = {
 568    .format_name                = "nbd",
 569    .protocol_name              = "nbd",
 570    .instance_size              = sizeof(BDRVNBDState),
 571    .bdrv_parse_filename        = nbd_parse_filename,
 572    .bdrv_file_open             = nbd_open,
 573    .bdrv_co_preadv             = nbd_client_co_preadv,
 574    .bdrv_co_pwritev            = nbd_client_co_pwritev,
 575    .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 576    .bdrv_close                 = nbd_close,
 577    .bdrv_co_flush_to_os        = nbd_co_flush,
 578    .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 579    .bdrv_refresh_limits        = nbd_refresh_limits,
 580    .bdrv_getlength             = nbd_getlength,
 581    .bdrv_detach_aio_context    = nbd_detach_aio_context,
 582    .bdrv_attach_aio_context    = nbd_attach_aio_context,
 583    .bdrv_refresh_filename      = nbd_refresh_filename,
 584    .bdrv_co_block_status       = nbd_client_co_block_status,
 585};
 586
 587static BlockDriver bdrv_nbd_tcp = {
 588    .format_name                = "nbd",
 589    .protocol_name              = "nbd+tcp",
 590    .instance_size              = sizeof(BDRVNBDState),
 591    .bdrv_parse_filename        = nbd_parse_filename,
 592    .bdrv_file_open             = nbd_open,
 593    .bdrv_co_preadv             = nbd_client_co_preadv,
 594    .bdrv_co_pwritev            = nbd_client_co_pwritev,
 595    .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 596    .bdrv_close                 = nbd_close,
 597    .bdrv_co_flush_to_os        = nbd_co_flush,
 598    .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 599    .bdrv_refresh_limits        = nbd_refresh_limits,
 600    .bdrv_getlength             = nbd_getlength,
 601    .bdrv_detach_aio_context    = nbd_detach_aio_context,
 602    .bdrv_attach_aio_context    = nbd_attach_aio_context,
 603    .bdrv_refresh_filename      = nbd_refresh_filename,
 604    .bdrv_co_block_status       = nbd_client_co_block_status,
 605};
 606
 607static BlockDriver bdrv_nbd_unix = {
 608    .format_name                = "nbd",
 609    .protocol_name              = "nbd+unix",
 610    .instance_size              = sizeof(BDRVNBDState),
 611    .bdrv_parse_filename        = nbd_parse_filename,
 612    .bdrv_file_open             = nbd_open,
 613    .bdrv_co_preadv             = nbd_client_co_preadv,
 614    .bdrv_co_pwritev            = nbd_client_co_pwritev,
 615    .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 616    .bdrv_close                 = nbd_close,
 617    .bdrv_co_flush_to_os        = nbd_co_flush,
 618    .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 619    .bdrv_refresh_limits        = nbd_refresh_limits,
 620    .bdrv_getlength             = nbd_getlength,
 621    .bdrv_detach_aio_context    = nbd_detach_aio_context,
 622    .bdrv_attach_aio_context    = nbd_attach_aio_context,
 623    .bdrv_refresh_filename      = nbd_refresh_filename,
 624    .bdrv_co_block_status       = nbd_client_co_block_status,
 625};
 626
 627static void bdrv_nbd_init(void)
 628{
 629    bdrv_register(&bdrv_nbd);
 630    bdrv_register(&bdrv_nbd_tcp);
 631    bdrv_register(&bdrv_nbd_unix);
 632}
 633
 634block_init(bdrv_nbd_init);
 635