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 "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
  46 typedef struct BDRVNBDState {
  47     NBDClientSession client;
  48
  49     /* For nbd_refresh_filename() */
  50     SocketAddress *saddr;
  51     char *export, *tlscredsid;
  52 } BDRVNBDState;
  53
  54 static 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
 125 out:
 126     if (qp) {
 127         query_params_free(qp);
 128     }
 129     uri_free(uri);
 130     return ret;
 131 }
 132
 133 static 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
 153 static 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
 214 out:
 215     g_free(file);
 216 }
 217
 218 static 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
 261 static 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
 286 done:
 287     qobject_unref(addr);
 288     visit_free(iv);
 289     return saddr;
 290 }
 291
 292 NBDClientSession *nbd_get_client_session(BlockDriverState *bs)
 293 {
 294     BDRVNBDState *s = bs->opaque;
 295     return &s->client;
 296 }
 297
 298 static 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
 322 static 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
 352 static 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
 391 static 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
 465 static int nbd_co_flush(BlockDriverState *bs)
 466 {
 467     return nbd_client_co_flush(bs);
 468 }
 469
 470 static 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
 487 static 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
 498 static int64_t nbd_getlength(BlockDriverState *bs)
 499 {
 500     BDRVNBDState *s = bs->opaque;
 501
 502     return s->client.info.size;
 503 }
 504
 505 static void nbd_detach_aio_context(BlockDriverState *bs)
 506 {
 507     nbd_client_detach_aio_context(bs);
 508 }
 509
 510 static void nbd_attach_aio_context(BlockDriverState *bs,
 511                                    AioContext *new_context)
 512 {
 513     nbd_client_attach_aio_context(bs, new_context);
 514 }
 515
 516 static 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
 567 static 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
 587 static 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
 607 static 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
 627 static 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
 634 block_init(bdrv_nbd_init);