block/nbd.c

   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 "block/nbd-client.h"
  31 #include "qapi/error.h"
  32 #include "qemu/uri.h"
  33 #include "block/block_int.h"
  34 #include "qemu/module.h"
  35 #include "qapi-visit.h"
  36 #include "qapi/qobject-input-visitor.h"
  37 #include "qapi/qobject-output-visitor.h"
  38 #include "qapi/qmp/qdict.h"
  39 #include "qapi/qmp/qjson.h"
  40 #include "qapi/qmp/qstring.h"
  41 #include "qemu/cutils.h"
  42
  43 #define EN_OPTSTR ":exportname="
  44
  45 typedef struct BDRVNBDState {
  46     NBDClientSession client;
  47
  48     /* For nbd_refresh_filename() */
  49     SocketAddress *saddr;
  50     char *export, *tlscredsid;
  51 } BDRVNBDState;
  52
  53 static int nbd_parse_uri(const char *filename, QDict *options)
  54 {
  55     URI *uri;
  56     const char *p;
  57     QueryParams *qp = NULL;
  58     int ret = 0;
  59     bool is_unix;
  60
  61     uri = uri_parse(filename);
  62     if (!uri) {
  63         return -EINVAL;
  64     }
  65
  66     /* transport */
  67     if (!g_strcmp0(uri->scheme, "nbd")) {
  68         is_unix = false;
  69     } else if (!g_strcmp0(uri->scheme, "nbd+tcp")) {
  70         is_unix = false;
  71     } else if (!g_strcmp0(uri->scheme, "nbd+unix")) {
  72         is_unix = true;
  73     } else {
  74         ret = -EINVAL;
  75         goto out;
  76     }
  77
  78     p = uri->path ? uri->path : "/";
  79     p += strspn(p, "/");
  80     if (p[0]) {
  81         qdict_put_str(options, "export", p);
  82     }
  83
  84     qp = query_params_parse(uri->query);
  85     if (qp->n > 1 || (is_unix && !qp->n) || (!is_unix && qp->n)) {
  86         ret = -EINVAL;
  87         goto out;
  88     }
  89
  90     if (is_unix) {
  91         /* nbd+unix:///export?socket=path */
  92         if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {
  93             ret = -EINVAL;
  94             goto out;
  95         }
  96         qdict_put_str(options, "server.type", "unix");
  97         qdict_put_str(options, "server.path", qp->p[0].value);
  98     } else {
  99         QString *host;
 100         char *port_str;
 101
 102         /* nbd[+tcp]://host[:port]/export */
 103         if (!uri->server) {
 104             ret = -EINVAL;
 105             goto out;
 106         }
 107
 108         /* strip braces from literal IPv6 address */
 109         if (uri->server[0] == '[') {
 110             host = qstring_from_substr(uri->server, 1,
 111                                        strlen(uri->server) - 2);
 112         } else {
 113             host = qstring_from_str(uri->server);
 114         }
 115
 116         qdict_put_str(options, "server.type", "inet");
 117         qdict_put(options, "server.host", host);
 118
 119         port_str = g_strdup_printf("%d", uri->port ?: NBD_DEFAULT_PORT);
 120         qdict_put_str(options, "server.port", port_str);
 121         g_free(port_str);
 122     }
 123
 124 out:
 125     if (qp) {
 126         query_params_free(qp);
 127     }
 128     uri_free(uri);
 129     return ret;
 130 }
 131
 132 static bool nbd_has_filename_options_conflict(QDict *options, Error **errp)
 133 {
 134     const QDictEntry *e;
 135
 136     for (e = qdict_first(options); e; e = qdict_next(options, e)) {
 137         if (!strcmp(e->key, "host") ||
 138             !strcmp(e->key, "port") ||
 139             !strcmp(e->key, "path") ||
 140             !strcmp(e->key, "export") ||
 141             strstart(e->key, "server.", NULL))
 142         {
 143             error_setg(errp, "Option '%s' cannot be used with a file name",
 144                        e->key);
 145             return true;
 146         }
 147     }
 148
 149     return false;
 150 }
 151
 152 static void nbd_parse_filename(const char *filename, QDict *options,
 153                                Error **errp)
 154 {
 155     char *file;
 156     char *export_name;
 157     const char *host_spec;
 158     const char *unixpath;
 159
 160     if (nbd_has_filename_options_conflict(options, errp)) {
 161         return;
 162     }
 163
 164     if (strstr(filename, "://")) {
 165         int ret = nbd_parse_uri(filename, options);
 166         if (ret < 0) {
 167             error_setg(errp, "No valid URL specified");
 168         }
 169         return;
 170     }
 171
 172     file = g_strdup(filename);
 173
 174     export_name = strstr(file, EN_OPTSTR);
 175     if (export_name) {
 176         if (export_name[strlen(EN_OPTSTR)] == 0) {
 177             goto out;
 178         }
 179         export_name[0] = 0; /* truncate 'file' */
 180         export_name += strlen(EN_OPTSTR);
 181
 182         qdict_put_str(options, "export", export_name);
 183     }
 184
 185     /* extract the host_spec - fail if it's not nbd:... */
 186     if (!strstart(file, "nbd:", &host_spec)) {
 187         error_setg(errp, "File name string for NBD must start with 'nbd:'");
 188         goto out;
 189     }
 190
 191     if (!*host_spec) {
 192         goto out;
 193     }
 194
 195     /* are we a UNIX or TCP socket? */
 196     if (strstart(host_spec, "unix:", &unixpath)) {
 197         qdict_put_str(options, "server.type", "unix");
 198         qdict_put_str(options, "server.path", unixpath);
 199     } else {
 200         InetSocketAddress *addr = g_new(InetSocketAddress, 1);
 201
 202         if (inet_parse(addr, host_spec, errp)) {
 203             goto out_inet;
 204         }
 205
 206         qdict_put_str(options, "server.type", "inet");
 207         qdict_put_str(options, "server.host", addr->host);
 208         qdict_put_str(options, "server.port", addr->port);
 209     out_inet:
 210         qapi_free_InetSocketAddress(addr);
 211     }
 212
 213 out:
 214     g_free(file);
 215 }
 216
 217 static bool nbd_process_legacy_socket_options(QDict *output_options,
 218                                               QemuOpts *legacy_opts,
 219                                               Error **errp)
 220 {
 221     const char *path = qemu_opt_get(legacy_opts, "path");
 222     const char *host = qemu_opt_get(legacy_opts, "host");
 223     const char *port = qemu_opt_get(legacy_opts, "port");
 224     const QDictEntry *e;
 225
 226     if (!path && !host && !port) {
 227         return true;
 228     }
 229
 230     for (e = qdict_first(output_options); e; e = qdict_next(output_options, e))
 231     {
 232         if (strstart(e->key, "server.", NULL)) {
 233             error_setg(errp, "Cannot use 'server' and path/host/port at the "
 234                        "same time");
 235             return false;
 236         }
 237     }
 238
 239     if (path && host) {
 240         error_setg(errp, "path and host may not be used at the same time");
 241         return false;
 242     } else if (path) {
 243         if (port) {
 244             error_setg(errp, "port may not be used without host");
 245             return false;
 246         }
 247
 248         qdict_put_str(output_options, "server.type", "unix");
 249         qdict_put_str(output_options, "server.path", path);
 250     } else if (host) {
 251         qdict_put_str(output_options, "server.type", "inet");
 252         qdict_put_str(output_options, "server.host", host);
 253         qdict_put_str(output_options, "server.port",
 254                       port ?: stringify(NBD_DEFAULT_PORT));
 255     }
 256
 257     return true;
 258 }
 259
 260 static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
 261                                  Error **errp)
 262 {
 263     SocketAddress *saddr = NULL;
 264     QDict *addr = NULL;
 265     QObject *crumpled_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     crumpled_addr = qdict_crumple(addr, errp);
 276     if (!crumpled_addr) {
 277         goto done;
 278     }
 279
 280     /*
 281      * FIXME .numeric, .to, .ipv4 or .ipv6 don't work with -drive
 282      * server.type=inet.  .to doesn't matter, it's ignored anyway.
 283      * That's because when @options come from -blockdev or
 284      * blockdev_add, members are typed according to the QAPI schema,
 285      * but when they come from -drive, they're all QString.  The
 286      * visitor expects the former.
 287      */
 288     iv = qobject_input_visitor_new(crumpled_addr);
 289     visit_type_SocketAddress(iv, NULL, &saddr, &local_err);
 290     if (local_err) {
 291         error_propagate(errp, local_err);
 292         goto done;
 293     }
 294
 295 done:
 296     QDECREF(addr);
 297     qobject_decref(crumpled_addr);
 298     visit_free(iv);
 299     return saddr;
 300 }
 301
 302 NBDClientSession *nbd_get_client_session(BlockDriverState *bs)
 303 {
 304     BDRVNBDState *s = bs->opaque;
 305     return &s->client;
 306 }
 307
 308 static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
 309                                                   Error **errp)
 310 {
 311     QIOChannelSocket *sioc;
 312     Error *local_err = NULL;
 313
 314     sioc = qio_channel_socket_new();
 315     qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
 316
 317     qio_channel_socket_connect_sync(sioc,
 318                                     saddr,
 319                                     &local_err);
 320     if (local_err) {
 321         object_unref(OBJECT(sioc));
 322         error_propagate(errp, local_err);
 323         return NULL;
 324     }
 325
 326     qio_channel_set_delay(QIO_CHANNEL(sioc), false);
 327
 328     return sioc;
 329 }
 330
 331
 332 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 333 {
 334     Object *obj;
 335     QCryptoTLSCreds *creds;
 336
 337     obj = object_resolve_path_component(
 338         object_get_objects_root(), id);
 339     if (!obj) {
 340         error_setg(errp, "No TLS credentials with id '%s'",
 341                    id);
 342         return NULL;
 343     }
 344     creds = (QCryptoTLSCreds *)
 345         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
 346     if (!creds) {
 347         error_setg(errp, "Object with id '%s' is not TLS credentials",
 348                    id);
 349         return NULL;
 350     }
 351
 352     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
 353         error_setg(errp,
 354                    "Expecting TLS credentials with a client endpoint");
 355         return NULL;
 356     }
 357     object_ref(obj);
 358     return creds;
 359 }
 360
 361
 362 static QemuOptsList nbd_runtime_opts = {
 363     .name = "nbd",
 364     .head = QTAILQ_HEAD_INITIALIZER(nbd_runtime_opts.head),
 365     .desc = {
 366         {
 367             .name = "host",
 368             .type = QEMU_OPT_STRING,
 369             .help = "TCP host to connect to",
 370         },
 371         {
 372             .name = "port",
 373             .type = QEMU_OPT_STRING,
 374             .help = "TCP port to connect to",
 375         },
 376         {
 377             .name = "path",
 378             .type = QEMU_OPT_STRING,
 379             .help = "Unix socket path to connect to",
 380         },
 381         {
 382             .name = "export",
 383             .type = QEMU_OPT_STRING,
 384             .help = "Name of the NBD export to open",
 385         },
 386         {
 387             .name = "tls-creds",
 388             .type = QEMU_OPT_STRING,
 389             .help = "ID of the TLS credentials to use",
 390         },
 391         { /* end of list */ }
 392     },
 393 };
 394
 395 static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
 396                     Error **errp)
 397 {
 398     BDRVNBDState *s = bs->opaque;
 399     QemuOpts *opts = NULL;
 400     Error *local_err = NULL;
 401     QIOChannelSocket *sioc = NULL;
 402     QCryptoTLSCreds *tlscreds = NULL;
 403     const char *hostname = NULL;
 404     int ret = -EINVAL;
 405
 406     opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
 407     qemu_opts_absorb_qdict(opts, options, &local_err);
 408     if (local_err) {
 409         error_propagate(errp, local_err);
 410         goto error;
 411     }
 412
 413     /* Translate @host, @port, and @path to a SocketAddress */
 414     if (!nbd_process_legacy_socket_options(options, opts, errp)) {
 415         goto error;
 416     }
 417
 418     /* Pop the config into our state object. Exit if invalid. */
 419     s->saddr = nbd_config(s, options, errp);
 420     if (!s->saddr) {
 421         goto error;
 422     }
 423
 424     s->export = g_strdup(qemu_opt_get(opts, "export"));
 425
 426     s->tlscredsid = g_strdup(qemu_opt_get(opts, "tls-creds"));
 427     if (s->tlscredsid) {
 428         tlscreds = nbd_get_tls_creds(s->tlscredsid, errp);
 429         if (!tlscreds) {
 430             goto error;
 431         }
 432
 433         /* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */
 434         if (s->saddr->type != SOCKET_ADDRESS_TYPE_INET) {
 435             error_setg(errp, "TLS only supported over IP sockets");
 436             goto error;
 437         }
 438         hostname = s->saddr->u.inet.host;
 439     }
 440
 441     /* establish TCP connection, return error if it fails
 442      * TODO: Configurable retry-until-timeout behaviour.
 443      */
 444     sioc = nbd_establish_connection(s->saddr, errp);
 445     if (!sioc) {
 446         ret = -ECONNREFUSED;
 447         goto error;
 448     }
 449
 450     /* NBD handshake */
 451     ret = nbd_client_init(bs, sioc, s->export,
 452                           tlscreds, hostname, errp);
 453  error:
 454     if (sioc) {
 455         object_unref(OBJECT(sioc));
 456     }
 457     if (tlscreds) {
 458         object_unref(OBJECT(tlscreds));
 459     }
 460     if (ret < 0) {
 461         qapi_free_SocketAddress(s->saddr);
 462         g_free(s->export);
 463         g_free(s->tlscredsid);
 464     }
 465     qemu_opts_del(opts);
 466     return ret;
 467 }
 468
 469 static int nbd_co_flush(BlockDriverState *bs)
 470 {
 471     return nbd_client_co_flush(bs);
 472 }
 473
 474 static void nbd_refresh_limits(BlockDriverState *bs, Error **errp)
 475 {
 476     NBDClientSession *s = nbd_get_client_session(bs);
 477     uint32_t max = MIN_NON_ZERO(NBD_MAX_BUFFER_SIZE, s->info.max_block);
 478
 479     bs->bl.max_pdiscard = max;
 480     bs->bl.max_pwrite_zeroes = max;
 481     bs->bl.max_transfer = max;
 482
 483     if (s->info.opt_block &&
 484         s->info.opt_block > bs->bl.opt_transfer) {
 485         bs->bl.opt_transfer = s->info.opt_block;
 486     }
 487 }
 488
 489 static void nbd_close(BlockDriverState *bs)
 490 {
 491     BDRVNBDState *s = bs->opaque;
 492
 493     nbd_client_close(bs);
 494
 495     qapi_free_SocketAddress(s->saddr);
 496     g_free(s->export);
 497     g_free(s->tlscredsid);
 498 }
 499
 500 static int64_t nbd_getlength(BlockDriverState *bs)
 501 {
 502     BDRVNBDState *s = bs->opaque;
 503
 504     return s->client.info.size;
 505 }
 506
 507 static void nbd_detach_aio_context(BlockDriverState *bs)
 508 {
 509     nbd_client_detach_aio_context(bs);
 510 }
 511
 512 static void nbd_attach_aio_context(BlockDriverState *bs,
 513                                    AioContext *new_context)
 514 {
 515     nbd_client_attach_aio_context(bs, new_context);
 516 }
 517
 518 static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
 519 {
 520     BDRVNBDState *s = bs->opaque;
 521     QDict *opts = qdict_new();
 522     QObject *saddr_qdict;
 523     Visitor *ov;
 524     const char *host = NULL, *port = NULL, *path = NULL;
 525
 526     if (s->saddr->type == SOCKET_ADDRESS_TYPE_INET) {
 527         const InetSocketAddress *inet = &s->saddr->u.inet;
 528         if (!inet->has_ipv4 && !inet->has_ipv6 && !inet->has_to) {
 529             host = inet->host;
 530             port = inet->port;
 531         }
 532     } else if (s->saddr->type == SOCKET_ADDRESS_TYPE_UNIX) {
 533         path = s->saddr->u.q_unix.path;
 534     } /* else can't represent as pseudo-filename */
 535
 536     qdict_put_str(opts, "driver", "nbd");
 537
 538     if (path && s->export) {
 539         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 540                  "nbd+unix:///%s?socket=%s", s->export, path);
 541     } else if (path && !s->export) {
 542         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 543                  "nbd+unix://?socket=%s", path);
 544     } else if (host && s->export) {
 545         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 546                  "nbd://%s:%s/%s", host, port, s->export);
 547     } else if (host && !s->export) {
 548         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 549                  "nbd://%s:%s", host, port);
 550     }
 551
 552     ov = qobject_output_visitor_new(&saddr_qdict);
 553     visit_type_SocketAddress(ov, NULL, &s->saddr, &error_abort);
 554     visit_complete(ov, &saddr_qdict);
 555     visit_free(ov);
 556     qdict_put_obj(opts, "server", saddr_qdict);
 557
 558     if (s->export) {
 559         qdict_put_str(opts, "export", s->export);
 560     }
 561     if (s->tlscredsid) {
 562         qdict_put_str(opts, "tls-creds", s->tlscredsid);
 563     }
 564
 565     qdict_flatten(opts);
 566     bs->full_open_options = opts;
 567 }
 568
 569 static int nbd_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 570 {
 571     if (bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP) {
 572         bdi->can_write_zeroes_with_unmap = true;
 573     }
 574     return 0;
 575 }
 576
 577 static BlockDriver bdrv_nbd = {
 578     .format_name                = "nbd",
 579     .protocol_name              = "nbd",
 580     .instance_size              = sizeof(BDRVNBDState),
 581     .bdrv_parse_filename        = nbd_parse_filename,
 582     .bdrv_file_open             = nbd_open,
 583     .bdrv_co_preadv             = nbd_client_co_preadv,
 584     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 585     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 586     .bdrv_close                 = nbd_close,
 587     .bdrv_co_flush_to_os        = nbd_co_flush,
 588     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 589     .bdrv_refresh_limits        = nbd_refresh_limits,
 590     .bdrv_getlength             = nbd_getlength,
 591     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 592     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 593     .bdrv_refresh_filename      = nbd_refresh_filename,
 594     .bdrv_get_info              = nbd_get_info,
 595 };
 596
 597 static BlockDriver bdrv_nbd_tcp = {
 598     .format_name                = "nbd",
 599     .protocol_name              = "nbd+tcp",
 600     .instance_size              = sizeof(BDRVNBDState),
 601     .bdrv_parse_filename        = nbd_parse_filename,
 602     .bdrv_file_open             = nbd_open,
 603     .bdrv_co_preadv             = nbd_client_co_preadv,
 604     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 605     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 606     .bdrv_close                 = nbd_close,
 607     .bdrv_co_flush_to_os        = nbd_co_flush,
 608     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 609     .bdrv_refresh_limits        = nbd_refresh_limits,
 610     .bdrv_getlength             = nbd_getlength,
 611     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 612     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 613     .bdrv_refresh_filename      = nbd_refresh_filename,
 614     .bdrv_get_info              = nbd_get_info,
 615 };
 616
 617 static BlockDriver bdrv_nbd_unix = {
 618     .format_name                = "nbd",
 619     .protocol_name              = "nbd+unix",
 620     .instance_size              = sizeof(BDRVNBDState),
 621     .bdrv_parse_filename        = nbd_parse_filename,
 622     .bdrv_file_open             = nbd_open,
 623     .bdrv_co_preadv             = nbd_client_co_preadv,
 624     .bdrv_co_pwritev            = nbd_client_co_pwritev,
 625     .bdrv_co_pwrite_zeroes      = nbd_client_co_pwrite_zeroes,
 626     .bdrv_close                 = nbd_close,
 627     .bdrv_co_flush_to_os        = nbd_co_flush,
 628     .bdrv_co_pdiscard           = nbd_client_co_pdiscard,
 629     .bdrv_refresh_limits        = nbd_refresh_limits,
 630     .bdrv_getlength             = nbd_getlength,
 631     .bdrv_detach_aio_context    = nbd_detach_aio_context,
 632     .bdrv_attach_aio_context    = nbd_attach_aio_context,
 633     .bdrv_refresh_filename      = nbd_refresh_filename,
 634     .bdrv_get_info              = nbd_get_info,
 635 };
 636
 637 static void bdrv_nbd_init(void)
 638 {
 639     bdrv_register(&bdrv_nbd);
 640     bdrv_register(&bdrv_nbd_tcp);
 641     bdrv_register(&bdrv_nbd_unix);
 642 }
 643
 644 block_init(bdrv_nbd_init);