1 /* 2 * Copyright (C) 2016-2017 Red Hat, Inc. 3 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> 4 * 5 * Network Block Device Server Side 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 #include "qemu/osdep.h" 21 #include "qapi/error.h" 22 #include "trace.h" 23 #include "nbd-internal.h" 24 25 static int system_errno_to_nbd_errno(int err) 26 { 27 switch (err) { 28 case 0: 29 return NBD_SUCCESS; 30 case EPERM: 31 case EROFS: 32 return NBD_EPERM; 33 case EIO: 34 return NBD_EIO; 35 case ENOMEM: 36 return NBD_ENOMEM; 37 #ifdef EDQUOT 38 case EDQUOT: 39 #endif 40 case EFBIG: 41 case ENOSPC: 42 return NBD_ENOSPC; 43 case EOVERFLOW: 44 return NBD_EOVERFLOW; 45 case ESHUTDOWN: 46 return NBD_ESHUTDOWN; 47 case EINVAL: 48 default: 49 return NBD_EINVAL; 50 } 51 } 52 53 /* Definitions for opaque data types */ 54 55 typedef struct NBDRequestData NBDRequestData; 56 57 struct NBDRequestData { 58 QSIMPLEQ_ENTRY(NBDRequestData) entry; 59 NBDClient *client; 60 uint8_t *data; 61 bool complete; 62 }; 63 64 struct NBDExport { 65 int refcount; 66 void (*close)(NBDExport *exp); 67 68 BlockBackend *blk; 69 char *name; 70 char *description; 71 off_t dev_offset; 72 off_t size; 73 uint16_t nbdflags; 74 QTAILQ_HEAD(, NBDClient) clients; 75 QTAILQ_ENTRY(NBDExport) next; 76 77 AioContext *ctx; 78 79 BlockBackend *eject_notifier_blk; 80 Notifier eject_notifier; 81 }; 82 83 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 84 85 struct NBDClient { 86 int refcount; 87 void (*close_fn)(NBDClient *client, bool negotiated); 88 89 NBDExport *exp; 90 QCryptoTLSCreds *tlscreds; 91 char *tlsaclname; 92 QIOChannelSocket *sioc; /* The underlying data channel */ 93 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 94 95 Coroutine *recv_coroutine; 96 97 CoMutex send_lock; 98 Coroutine *send_coroutine; 99 100 QTAILQ_ENTRY(NBDClient) next; 101 int nb_requests; 102 bool closing; 103 104 bool structured_reply; 105 }; 106 107 /* That's all folks */ 108 109 static void nbd_client_receive_next_request(NBDClient *client); 110 111 /* Basic flow for negotiation 112 113 Server Client 114 Negotiate 115 116 or 117 118 Server Client 119 Negotiate #1 120 Option 121 Negotiate #2 122 123 ---- 124 125 followed by 126 127 Server Client 128 Request 129 Response 130 Request 131 Response 132 ... 133 ... 134 Request (type == 2) 135 136 */ 137 138 /* Send a reply header, including length, but no payload. 139 * Return -errno on error, 0 on success. */ 140 static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type, 141 uint32_t opt, uint32_t len, Error **errp) 142 { 143 uint64_t magic; 144 145 trace_nbd_negotiate_send_rep_len(opt, nbd_opt_lookup(opt), 146 type, nbd_rep_lookup(type), len); 147 148 assert(len < NBD_MAX_BUFFER_SIZE); 149 magic = cpu_to_be64(NBD_REP_MAGIC); 150 if (nbd_write(ioc, &magic, sizeof(magic), errp) < 0) { 151 error_prepend(errp, "write failed (rep magic): "); 152 return -EINVAL; 153 } 154 155 opt = cpu_to_be32(opt); 156 if (nbd_write(ioc, &opt, sizeof(opt), errp) < 0) { 157 error_prepend(errp, "write failed (rep opt): "); 158 return -EINVAL; 159 } 160 161 type = cpu_to_be32(type); 162 if (nbd_write(ioc, &type, sizeof(type), errp) < 0) { 163 error_prepend(errp, "write failed (rep type): "); 164 return -EINVAL; 165 } 166 167 len = cpu_to_be32(len); 168 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 169 error_prepend(errp, "write failed (rep data length): "); 170 return -EINVAL; 171 } 172 return 0; 173 } 174 175 /* Send a reply header with default 0 length. 176 * Return -errno on error, 0 on success. */ 177 static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt, 178 Error **errp) 179 { 180 return nbd_negotiate_send_rep_len(ioc, type, opt, 0, errp); 181 } 182 183 /* Send an error reply. 184 * Return -errno on error, 0 on success. */ 185 static int GCC_FMT_ATTR(5, 6) 186 nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type, 187 uint32_t opt, Error **errp, const char *fmt, ...) 188 { 189 va_list va; 190 char *msg; 191 int ret; 192 size_t len; 193 194 va_start(va, fmt); 195 msg = g_strdup_vprintf(fmt, va); 196 va_end(va); 197 len = strlen(msg); 198 assert(len < 4096); 199 trace_nbd_negotiate_send_rep_err(msg); 200 ret = nbd_negotiate_send_rep_len(ioc, type, opt, len, errp); 201 if (ret < 0) { 202 goto out; 203 } 204 if (nbd_write(ioc, msg, len, errp) < 0) { 205 error_prepend(errp, "write failed (error message): "); 206 ret = -EIO; 207 } else { 208 ret = 0; 209 } 210 211 out: 212 g_free(msg); 213 return ret; 214 } 215 216 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 217 * Return -errno on error, 0 on success. */ 218 static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp, 219 Error **errp) 220 { 221 size_t name_len, desc_len; 222 uint32_t len; 223 const char *name = exp->name ? exp->name : ""; 224 const char *desc = exp->description ? exp->description : ""; 225 int ret; 226 227 trace_nbd_negotiate_send_rep_list(name, desc); 228 name_len = strlen(name); 229 desc_len = strlen(desc); 230 len = name_len + desc_len + sizeof(len); 231 ret = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len, 232 errp); 233 if (ret < 0) { 234 return ret; 235 } 236 237 len = cpu_to_be32(name_len); 238 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 239 error_prepend(errp, "write failed (name length): "); 240 return -EINVAL; 241 } 242 243 if (nbd_write(ioc, name, name_len, errp) < 0) { 244 error_prepend(errp, "write failed (name buffer): "); 245 return -EINVAL; 246 } 247 248 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 249 error_prepend(errp, "write failed (description buffer): "); 250 return -EINVAL; 251 } 252 253 return 0; 254 } 255 256 /* Process the NBD_OPT_LIST command, with a potential series of replies. 257 * Return -errno on error, 0 on success. */ 258 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 259 { 260 NBDExport *exp; 261 262 /* For each export, send a NBD_REP_SERVER reply. */ 263 QTAILQ_FOREACH(exp, &exports, next) { 264 if (nbd_negotiate_send_rep_list(client->ioc, exp, errp)) { 265 return -EINVAL; 266 } 267 } 268 /* Finish with a NBD_REP_ACK. */ 269 return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST, errp); 270 } 271 272 /* Send a reply to NBD_OPT_EXPORT_NAME. 273 * Return -errno on error, 0 on success. */ 274 static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length, 275 uint16_t myflags, bool no_zeroes, 276 Error **errp) 277 { 278 char name[NBD_MAX_NAME_SIZE + 1]; 279 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 280 size_t len; 281 int ret; 282 283 /* Client sends: 284 [20 .. xx] export name (length bytes) 285 Server replies: 286 [ 0 .. 7] size 287 [ 8 .. 9] export flags 288 [10 .. 133] reserved (0) [unless no_zeroes] 289 */ 290 trace_nbd_negotiate_handle_export_name(); 291 if (length >= sizeof(name)) { 292 error_setg(errp, "Bad length received"); 293 return -EINVAL; 294 } 295 if (nbd_read(client->ioc, name, length, errp) < 0) { 296 error_prepend(errp, "read failed: "); 297 return -EINVAL; 298 } 299 name[length] = '\0'; 300 301 trace_nbd_negotiate_handle_export_name_request(name); 302 303 client->exp = nbd_export_find(name); 304 if (!client->exp) { 305 error_setg(errp, "export not found"); 306 return -EINVAL; 307 } 308 309 trace_nbd_negotiate_new_style_size_flags(client->exp->size, 310 client->exp->nbdflags | myflags); 311 stq_be_p(buf, client->exp->size); 312 stw_be_p(buf + 8, client->exp->nbdflags | myflags); 313 len = no_zeroes ? 10 : sizeof(buf); 314 ret = nbd_write(client->ioc, buf, len, errp); 315 if (ret < 0) { 316 error_prepend(errp, "write failed: "); 317 return ret; 318 } 319 320 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 321 nbd_export_get(client->exp); 322 323 return 0; 324 } 325 326 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 327 * The buffer does NOT include the info type prefix. 328 * Return -errno on error, 0 if ready to send more. */ 329 static int nbd_negotiate_send_info(NBDClient *client, uint32_t opt, 330 uint16_t info, uint32_t length, void *buf, 331 Error **errp) 332 { 333 int rc; 334 335 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 336 rc = nbd_negotiate_send_rep_len(client->ioc, NBD_REP_INFO, opt, 337 sizeof(info) + length, errp); 338 if (rc < 0) { 339 return rc; 340 } 341 cpu_to_be16s(&info); 342 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 343 return -EIO; 344 } 345 if (nbd_write(client->ioc, buf, length, errp) < 0) { 346 return -EIO; 347 } 348 return 0; 349 } 350 351 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 352 * Return -errno on error, 0 if ready for next option, and 1 to move 353 * into transmission phase. */ 354 static int nbd_negotiate_handle_info(NBDClient *client, uint32_t length, 355 uint32_t opt, uint16_t myflags, 356 Error **errp) 357 { 358 int rc; 359 char name[NBD_MAX_NAME_SIZE + 1]; 360 NBDExport *exp; 361 uint16_t requests; 362 uint16_t request; 363 uint32_t namelen; 364 bool sendname = false; 365 bool blocksize = false; 366 uint32_t sizes[3]; 367 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 368 const char *msg; 369 370 /* Client sends: 371 4 bytes: L, name length (can be 0) 372 L bytes: export name 373 2 bytes: N, number of requests (can be 0) 374 N * 2 bytes: N requests 375 */ 376 if (length < sizeof(namelen) + sizeof(requests)) { 377 msg = "overall request too short"; 378 goto invalid; 379 } 380 if (nbd_read(client->ioc, &namelen, sizeof(namelen), errp) < 0) { 381 return -EIO; 382 } 383 be32_to_cpus(&namelen); 384 length -= sizeof(namelen); 385 if (namelen > length - sizeof(requests) || (length - namelen) % 2) { 386 msg = "name length is incorrect"; 387 goto invalid; 388 } 389 if (nbd_read(client->ioc, name, namelen, errp) < 0) { 390 return -EIO; 391 } 392 name[namelen] = '\0'; 393 length -= namelen; 394 trace_nbd_negotiate_handle_export_name_request(name); 395 396 if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) { 397 return -EIO; 398 } 399 be16_to_cpus(&requests); 400 length -= sizeof(requests); 401 trace_nbd_negotiate_handle_info_requests(requests); 402 if (requests != length / sizeof(request)) { 403 msg = "incorrect number of requests for overall length"; 404 goto invalid; 405 } 406 while (requests--) { 407 if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) { 408 return -EIO; 409 } 410 be16_to_cpus(&request); 411 length -= sizeof(request); 412 trace_nbd_negotiate_handle_info_request(request, 413 nbd_info_lookup(request)); 414 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 415 * everything else is either a request we don't know or 416 * something we send regardless of request */ 417 switch (request) { 418 case NBD_INFO_NAME: 419 sendname = true; 420 break; 421 case NBD_INFO_BLOCK_SIZE: 422 blocksize = true; 423 break; 424 } 425 } 426 427 exp = nbd_export_find(name); 428 if (!exp) { 429 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN, 430 opt, errp, "export '%s' not present", 431 name); 432 } 433 434 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 435 if (sendname) { 436 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, length, name, 437 errp); 438 if (rc < 0) { 439 return rc; 440 } 441 } 442 443 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 444 * client request */ 445 if (exp->description) { 446 size_t len = strlen(exp->description); 447 448 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION, 449 len, exp->description, errp); 450 if (rc < 0) { 451 return rc; 452 } 453 } 454 455 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 456 * according to whether the client requested it, and according to 457 * whether this is OPT_INFO or OPT_GO. */ 458 /* minimum - 1 for back-compat, or 512 if client is new enough. 459 * TODO: consult blk_bs(blk)->bl.request_alignment? */ 460 sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1; 461 /* preferred - Hard-code to 4096 for now. 462 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 463 sizes[1] = 4096; 464 /* maximum - At most 32M, but smaller as appropriate. */ 465 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 466 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 467 cpu_to_be32s(&sizes[0]); 468 cpu_to_be32s(&sizes[1]); 469 cpu_to_be32s(&sizes[2]); 470 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE, 471 sizeof(sizes), sizes, errp); 472 if (rc < 0) { 473 return rc; 474 } 475 476 /* Send NBD_INFO_EXPORT always */ 477 trace_nbd_negotiate_new_style_size_flags(exp->size, 478 exp->nbdflags | myflags); 479 stq_be_p(buf, exp->size); 480 stw_be_p(buf + 8, exp->nbdflags | myflags); 481 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT, 482 sizeof(buf), buf, errp); 483 if (rc < 0) { 484 return rc; 485 } 486 487 /* If the client is just asking for NBD_OPT_INFO, but forgot to 488 * request block sizes, return an error. 489 * TODO: consult blk_bs(blk)->request_align, and only error if it 490 * is not 1? */ 491 if (opt == NBD_OPT_INFO && !blocksize) { 492 return nbd_negotiate_send_rep_err(client->ioc, 493 NBD_REP_ERR_BLOCK_SIZE_REQD, opt, 494 errp, 495 "request NBD_INFO_BLOCK_SIZE to " 496 "use this export"); 497 } 498 499 /* Final reply */ 500 rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp); 501 if (rc < 0) { 502 return rc; 503 } 504 505 if (opt == NBD_OPT_GO) { 506 client->exp = exp; 507 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 508 nbd_export_get(client->exp); 509 rc = 1; 510 } 511 return rc; 512 513 invalid: 514 if (nbd_drop(client->ioc, length, errp) < 0) { 515 return -EIO; 516 } 517 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt, 518 errp, "%s", msg); 519 } 520 521 522 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 523 * new channel for all further (now-encrypted) communication. */ 524 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 525 Error **errp) 526 { 527 QIOChannel *ioc; 528 QIOChannelTLS *tioc; 529 struct NBDTLSHandshakeData data = { 0 }; 530 531 trace_nbd_negotiate_handle_starttls(); 532 ioc = client->ioc; 533 534 if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, 535 NBD_OPT_STARTTLS, errp) < 0) { 536 return NULL; 537 } 538 539 tioc = qio_channel_tls_new_server(ioc, 540 client->tlscreds, 541 client->tlsaclname, 542 errp); 543 if (!tioc) { 544 return NULL; 545 } 546 547 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 548 trace_nbd_negotiate_handle_starttls_handshake(); 549 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 550 qio_channel_tls_handshake(tioc, 551 nbd_tls_handshake, 552 &data, 553 NULL); 554 555 if (!data.complete) { 556 g_main_loop_run(data.loop); 557 } 558 g_main_loop_unref(data.loop); 559 if (data.error) { 560 object_unref(OBJECT(tioc)); 561 error_propagate(errp, data.error); 562 return NULL; 563 } 564 565 return QIO_CHANNEL(tioc); 566 } 567 568 /* nbd_reject_length: Handle any unexpected payload. 569 * @fatal requests that we quit talking to the client, even if we are able 570 * to successfully send an error to the guest. 571 * Return: 572 * -errno transmission error occurred or @fatal was requested, errp is set 573 * 0 error message successfully sent to client, errp is not set 574 */ 575 static int nbd_reject_length(NBDClient *client, uint32_t length, 576 uint32_t option, bool fatal, Error **errp) 577 { 578 int ret; 579 580 assert(length); 581 if (nbd_drop(client->ioc, length, errp) < 0) { 582 return -EIO; 583 } 584 ret = nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, 585 option, errp, 586 "option '%s' should have zero length", 587 nbd_opt_lookup(option)); 588 if (fatal && !ret) { 589 error_setg(errp, "option '%s' should have zero length", 590 nbd_opt_lookup(option)); 591 return -EINVAL; 592 } 593 return ret; 594 } 595 596 /* nbd_negotiate_options 597 * Process all NBD_OPT_* client option commands, during fixed newstyle 598 * negotiation. 599 * Return: 600 * -errno on error, errp is set 601 * 0 on successful negotiation, errp is not set 602 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 603 * errp is not set 604 */ 605 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 606 Error **errp) 607 { 608 uint32_t flags; 609 bool fixedNewstyle = false; 610 bool no_zeroes = false; 611 612 /* Client sends: 613 [ 0 .. 3] client flags 614 615 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 616 [ 0 .. 7] NBD_OPTS_MAGIC 617 [ 8 .. 11] NBD option 618 [12 .. 15] Data length 619 ... Rest of request 620 621 [ 0 .. 7] NBD_OPTS_MAGIC 622 [ 8 .. 11] Second NBD option 623 [12 .. 15] Data length 624 ... Rest of request 625 */ 626 627 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) { 628 error_prepend(errp, "read failed: "); 629 return -EIO; 630 } 631 be32_to_cpus(&flags); 632 trace_nbd_negotiate_options_flags(flags); 633 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 634 fixedNewstyle = true; 635 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 636 } 637 if (flags & NBD_FLAG_C_NO_ZEROES) { 638 no_zeroes = true; 639 flags &= ~NBD_FLAG_C_NO_ZEROES; 640 } 641 if (flags != 0) { 642 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 643 return -EINVAL; 644 } 645 646 while (1) { 647 int ret; 648 uint32_t option, length; 649 uint64_t magic; 650 651 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) { 652 error_prepend(errp, "read failed: "); 653 return -EINVAL; 654 } 655 magic = be64_to_cpu(magic); 656 trace_nbd_negotiate_options_check_magic(magic); 657 if (magic != NBD_OPTS_MAGIC) { 658 error_setg(errp, "Bad magic received"); 659 return -EINVAL; 660 } 661 662 if (nbd_read(client->ioc, &option, 663 sizeof(option), errp) < 0) { 664 error_prepend(errp, "read failed: "); 665 return -EINVAL; 666 } 667 option = be32_to_cpu(option); 668 669 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) { 670 error_prepend(errp, "read failed: "); 671 return -EINVAL; 672 } 673 length = be32_to_cpu(length); 674 675 trace_nbd_negotiate_options_check_option(option, 676 nbd_opt_lookup(option)); 677 if (client->tlscreds && 678 client->ioc == (QIOChannel *)client->sioc) { 679 QIOChannel *tioc; 680 if (!fixedNewstyle) { 681 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 682 return -EINVAL; 683 } 684 switch (option) { 685 case NBD_OPT_STARTTLS: 686 if (length) { 687 /* Unconditionally drop the connection if the client 688 * can't start a TLS negotiation correctly */ 689 return nbd_reject_length(client, length, option, true, 690 errp); 691 } 692 tioc = nbd_negotiate_handle_starttls(client, errp); 693 if (!tioc) { 694 return -EIO; 695 } 696 ret = 0; 697 object_unref(OBJECT(client->ioc)); 698 client->ioc = QIO_CHANNEL(tioc); 699 break; 700 701 case NBD_OPT_EXPORT_NAME: 702 /* No way to return an error to client, so drop connection */ 703 error_setg(errp, "Option 0x%x not permitted before TLS", 704 option); 705 return -EINVAL; 706 707 default: 708 if (nbd_drop(client->ioc, length, errp) < 0) { 709 return -EIO; 710 } 711 ret = nbd_negotiate_send_rep_err(client->ioc, 712 NBD_REP_ERR_TLS_REQD, 713 option, errp, 714 "Option 0x%" PRIx32 715 "not permitted before TLS", 716 option); 717 /* Let the client keep trying, unless they asked to 718 * quit. In this mode, we've already sent an error, so 719 * we can't ack the abort. */ 720 if (option == NBD_OPT_ABORT) { 721 return 1; 722 } 723 break; 724 } 725 } else if (fixedNewstyle) { 726 switch (option) { 727 case NBD_OPT_LIST: 728 if (length) { 729 ret = nbd_reject_length(client, length, option, false, 730 errp); 731 } else { 732 ret = nbd_negotiate_handle_list(client, errp); 733 } 734 break; 735 736 case NBD_OPT_ABORT: 737 /* NBD spec says we must try to reply before 738 * disconnecting, but that we must also tolerate 739 * guests that don't wait for our reply. */ 740 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL); 741 return 1; 742 743 case NBD_OPT_EXPORT_NAME: 744 return nbd_negotiate_handle_export_name(client, length, 745 myflags, no_zeroes, 746 errp); 747 748 case NBD_OPT_INFO: 749 case NBD_OPT_GO: 750 ret = nbd_negotiate_handle_info(client, length, option, 751 myflags, errp); 752 if (ret == 1) { 753 assert(option == NBD_OPT_GO); 754 return 0; 755 } 756 break; 757 758 case NBD_OPT_STARTTLS: 759 if (length) { 760 ret = nbd_reject_length(client, length, option, false, 761 errp); 762 } else if (client->tlscreds) { 763 ret = nbd_negotiate_send_rep_err(client->ioc, 764 NBD_REP_ERR_INVALID, 765 option, errp, 766 "TLS already enabled"); 767 } else { 768 ret = nbd_negotiate_send_rep_err(client->ioc, 769 NBD_REP_ERR_POLICY, 770 option, errp, 771 "TLS not configured"); 772 } 773 break; 774 775 case NBD_OPT_STRUCTURED_REPLY: 776 if (length) { 777 ret = nbd_reject_length(client, length, option, false, 778 errp); 779 } else if (client->structured_reply) { 780 ret = nbd_negotiate_send_rep_err( 781 client->ioc, NBD_REP_ERR_INVALID, option, errp, 782 "structured reply already negotiated"); 783 } else { 784 ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, 785 option, errp); 786 client->structured_reply = true; 787 myflags |= NBD_FLAG_SEND_DF; 788 } 789 break; 790 791 default: 792 if (nbd_drop(client->ioc, length, errp) < 0) { 793 return -EIO; 794 } 795 ret = nbd_negotiate_send_rep_err(client->ioc, 796 NBD_REP_ERR_UNSUP, 797 option, errp, 798 "Unsupported option 0x%" 799 PRIx32 " (%s)", option, 800 nbd_opt_lookup(option)); 801 break; 802 } 803 } else { 804 /* 805 * If broken new-style we should drop the connection 806 * for anything except NBD_OPT_EXPORT_NAME 807 */ 808 switch (option) { 809 case NBD_OPT_EXPORT_NAME: 810 return nbd_negotiate_handle_export_name(client, length, 811 myflags, no_zeroes, 812 errp); 813 814 default: 815 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)", 816 option, nbd_opt_lookup(option)); 817 return -EINVAL; 818 } 819 } 820 if (ret < 0) { 821 return ret; 822 } 823 } 824 } 825 826 /* nbd_negotiate 827 * Return: 828 * -errno on error, errp is set 829 * 0 on successful negotiation, errp is not set 830 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 831 * errp is not set 832 */ 833 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 834 { 835 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 836 int ret; 837 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 838 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 839 NBD_FLAG_SEND_WRITE_ZEROES); 840 bool oldStyle; 841 842 /* Old style negotiation header, no room for options 843 [ 0 .. 7] passwd ("NBDMAGIC") 844 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 845 [16 .. 23] size 846 [24 .. 27] export flags (zero-extended) 847 [28 .. 151] reserved (0) 848 849 New style negotiation header, client can send options 850 [ 0 .. 7] passwd ("NBDMAGIC") 851 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 852 [16 .. 17] server flags (0) 853 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 854 */ 855 856 qio_channel_set_blocking(client->ioc, false, NULL); 857 858 trace_nbd_negotiate_begin(); 859 memcpy(buf, "NBDMAGIC", 8); 860 861 oldStyle = client->exp != NULL && !client->tlscreds; 862 if (oldStyle) { 863 trace_nbd_negotiate_old_style(client->exp->size, 864 client->exp->nbdflags | myflags); 865 stq_be_p(buf + 8, NBD_CLIENT_MAGIC); 866 stq_be_p(buf + 16, client->exp->size); 867 stl_be_p(buf + 24, client->exp->nbdflags | myflags); 868 869 if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) { 870 error_prepend(errp, "write failed: "); 871 return -EINVAL; 872 } 873 } else { 874 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 875 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 876 877 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 878 error_prepend(errp, "write failed: "); 879 return -EINVAL; 880 } 881 ret = nbd_negotiate_options(client, myflags, errp); 882 if (ret != 0) { 883 if (ret < 0) { 884 error_prepend(errp, "option negotiation failed: "); 885 } 886 return ret; 887 } 888 } 889 890 trace_nbd_negotiate_success(); 891 892 return 0; 893 } 894 895 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 896 Error **errp) 897 { 898 uint8_t buf[NBD_REQUEST_SIZE]; 899 uint32_t magic; 900 int ret; 901 902 ret = nbd_read(ioc, buf, sizeof(buf), errp); 903 if (ret < 0) { 904 return ret; 905 } 906 907 /* Request 908 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 909 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 910 [ 6 .. 7] type (NBD_CMD_READ, ...) 911 [ 8 .. 15] handle 912 [16 .. 23] from 913 [24 .. 27] len 914 */ 915 916 magic = ldl_be_p(buf); 917 request->flags = lduw_be_p(buf + 4); 918 request->type = lduw_be_p(buf + 6); 919 request->handle = ldq_be_p(buf + 8); 920 request->from = ldq_be_p(buf + 16); 921 request->len = ldl_be_p(buf + 24); 922 923 trace_nbd_receive_request(magic, request->flags, request->type, 924 request->from, request->len); 925 926 if (magic != NBD_REQUEST_MAGIC) { 927 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 928 return -EINVAL; 929 } 930 return 0; 931 } 932 933 #define MAX_NBD_REQUESTS 16 934 935 void nbd_client_get(NBDClient *client) 936 { 937 client->refcount++; 938 } 939 940 void nbd_client_put(NBDClient *client) 941 { 942 if (--client->refcount == 0) { 943 /* The last reference should be dropped by client->close, 944 * which is called by client_close. 945 */ 946 assert(client->closing); 947 948 qio_channel_detach_aio_context(client->ioc); 949 object_unref(OBJECT(client->sioc)); 950 object_unref(OBJECT(client->ioc)); 951 if (client->tlscreds) { 952 object_unref(OBJECT(client->tlscreds)); 953 } 954 g_free(client->tlsaclname); 955 if (client->exp) { 956 QTAILQ_REMOVE(&client->exp->clients, client, next); 957 nbd_export_put(client->exp); 958 } 959 g_free(client); 960 } 961 } 962 963 static void client_close(NBDClient *client, bool negotiated) 964 { 965 if (client->closing) { 966 return; 967 } 968 969 client->closing = true; 970 971 /* Force requests to finish. They will drop their own references, 972 * then we'll close the socket and free the NBDClient. 973 */ 974 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 975 NULL); 976 977 /* Also tell the client, so that they release their reference. */ 978 if (client->close_fn) { 979 client->close_fn(client, negotiated); 980 } 981 } 982 983 static NBDRequestData *nbd_request_get(NBDClient *client) 984 { 985 NBDRequestData *req; 986 987 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 988 client->nb_requests++; 989 990 req = g_new0(NBDRequestData, 1); 991 nbd_client_get(client); 992 req->client = client; 993 return req; 994 } 995 996 static void nbd_request_put(NBDRequestData *req) 997 { 998 NBDClient *client = req->client; 999 1000 if (req->data) { 1001 qemu_vfree(req->data); 1002 } 1003 g_free(req); 1004 1005 client->nb_requests--; 1006 nbd_client_receive_next_request(client); 1007 1008 nbd_client_put(client); 1009 } 1010 1011 static void blk_aio_attached(AioContext *ctx, void *opaque) 1012 { 1013 NBDExport *exp = opaque; 1014 NBDClient *client; 1015 1016 trace_nbd_blk_aio_attached(exp->name, ctx); 1017 1018 exp->ctx = ctx; 1019 1020 QTAILQ_FOREACH(client, &exp->clients, next) { 1021 qio_channel_attach_aio_context(client->ioc, ctx); 1022 if (client->recv_coroutine) { 1023 aio_co_schedule(ctx, client->recv_coroutine); 1024 } 1025 if (client->send_coroutine) { 1026 aio_co_schedule(ctx, client->send_coroutine); 1027 } 1028 } 1029 } 1030 1031 static void blk_aio_detach(void *opaque) 1032 { 1033 NBDExport *exp = opaque; 1034 NBDClient *client; 1035 1036 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1037 1038 QTAILQ_FOREACH(client, &exp->clients, next) { 1039 qio_channel_detach_aio_context(client->ioc); 1040 } 1041 1042 exp->ctx = NULL; 1043 } 1044 1045 static void nbd_eject_notifier(Notifier *n, void *data) 1046 { 1047 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1048 nbd_export_close(exp); 1049 } 1050 1051 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, 1052 uint16_t nbdflags, void (*close)(NBDExport *), 1053 bool writethrough, BlockBackend *on_eject_blk, 1054 Error **errp) 1055 { 1056 AioContext *ctx; 1057 BlockBackend *blk; 1058 NBDExport *exp = g_new0(NBDExport, 1); 1059 uint64_t perm; 1060 int ret; 1061 1062 /* 1063 * NBD exports are used for non-shared storage migration. Make sure 1064 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1065 * access since the export could be available before migration handover. 1066 */ 1067 ctx = bdrv_get_aio_context(bs); 1068 aio_context_acquire(ctx); 1069 bdrv_invalidate_cache(bs, NULL); 1070 aio_context_release(ctx); 1071 1072 /* Don't allow resize while the NBD server is running, otherwise we don't 1073 * care what happens with the node. */ 1074 perm = BLK_PERM_CONSISTENT_READ; 1075 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1076 perm |= BLK_PERM_WRITE; 1077 } 1078 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1079 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1080 ret = blk_insert_bs(blk, bs, errp); 1081 if (ret < 0) { 1082 goto fail; 1083 } 1084 blk_set_enable_write_cache(blk, !writethrough); 1085 1086 exp->refcount = 1; 1087 QTAILQ_INIT(&exp->clients); 1088 exp->blk = blk; 1089 exp->dev_offset = dev_offset; 1090 exp->nbdflags = nbdflags; 1091 exp->size = size < 0 ? blk_getlength(blk) : size; 1092 if (exp->size < 0) { 1093 error_setg_errno(errp, -exp->size, 1094 "Failed to determine the NBD export's length"); 1095 goto fail; 1096 } 1097 exp->size -= exp->size % BDRV_SECTOR_SIZE; 1098 1099 exp->close = close; 1100 exp->ctx = blk_get_aio_context(blk); 1101 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1102 1103 if (on_eject_blk) { 1104 blk_ref(on_eject_blk); 1105 exp->eject_notifier_blk = on_eject_blk; 1106 exp->eject_notifier.notify = nbd_eject_notifier; 1107 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1108 } 1109 return exp; 1110 1111 fail: 1112 blk_unref(blk); 1113 g_free(exp); 1114 return NULL; 1115 } 1116 1117 NBDExport *nbd_export_find(const char *name) 1118 { 1119 NBDExport *exp; 1120 QTAILQ_FOREACH(exp, &exports, next) { 1121 if (strcmp(name, exp->name) == 0) { 1122 return exp; 1123 } 1124 } 1125 1126 return NULL; 1127 } 1128 1129 void nbd_export_set_name(NBDExport *exp, const char *name) 1130 { 1131 if (exp->name == name) { 1132 return; 1133 } 1134 1135 nbd_export_get(exp); 1136 if (exp->name != NULL) { 1137 g_free(exp->name); 1138 exp->name = NULL; 1139 QTAILQ_REMOVE(&exports, exp, next); 1140 nbd_export_put(exp); 1141 } 1142 if (name != NULL) { 1143 nbd_export_get(exp); 1144 exp->name = g_strdup(name); 1145 QTAILQ_INSERT_TAIL(&exports, exp, next); 1146 } 1147 nbd_export_put(exp); 1148 } 1149 1150 void nbd_export_set_description(NBDExport *exp, const char *description) 1151 { 1152 g_free(exp->description); 1153 exp->description = g_strdup(description); 1154 } 1155 1156 void nbd_export_close(NBDExport *exp) 1157 { 1158 NBDClient *client, *next; 1159 1160 nbd_export_get(exp); 1161 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1162 client_close(client, true); 1163 } 1164 nbd_export_set_name(exp, NULL); 1165 nbd_export_set_description(exp, NULL); 1166 nbd_export_put(exp); 1167 } 1168 1169 void nbd_export_get(NBDExport *exp) 1170 { 1171 assert(exp->refcount > 0); 1172 exp->refcount++; 1173 } 1174 1175 void nbd_export_put(NBDExport *exp) 1176 { 1177 assert(exp->refcount > 0); 1178 if (exp->refcount == 1) { 1179 nbd_export_close(exp); 1180 } 1181 1182 if (--exp->refcount == 0) { 1183 assert(exp->name == NULL); 1184 assert(exp->description == NULL); 1185 1186 if (exp->close) { 1187 exp->close(exp); 1188 } 1189 1190 if (exp->blk) { 1191 if (exp->eject_notifier_blk) { 1192 notifier_remove(&exp->eject_notifier); 1193 blk_unref(exp->eject_notifier_blk); 1194 } 1195 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1196 blk_aio_detach, exp); 1197 blk_unref(exp->blk); 1198 exp->blk = NULL; 1199 } 1200 1201 g_free(exp); 1202 } 1203 } 1204 1205 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1206 { 1207 return exp->blk; 1208 } 1209 1210 void nbd_export_close_all(void) 1211 { 1212 NBDExport *exp, *next; 1213 1214 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1215 nbd_export_close(exp); 1216 } 1217 } 1218 1219 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1220 unsigned niov, Error **errp) 1221 { 1222 int ret; 1223 1224 g_assert(qemu_in_coroutine()); 1225 qemu_co_mutex_lock(&client->send_lock); 1226 client->send_coroutine = qemu_coroutine_self(); 1227 1228 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1229 1230 client->send_coroutine = NULL; 1231 qemu_co_mutex_unlock(&client->send_lock); 1232 1233 return ret; 1234 } 1235 1236 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1237 uint64_t handle) 1238 { 1239 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1240 stl_be_p(&reply->error, error); 1241 stq_be_p(&reply->handle, handle); 1242 } 1243 1244 static int nbd_co_send_simple_reply(NBDClient *client, 1245 uint64_t handle, 1246 uint32_t error, 1247 void *data, 1248 size_t len, 1249 Error **errp) 1250 { 1251 NBDSimpleReply reply; 1252 int nbd_err = system_errno_to_nbd_errno(error); 1253 struct iovec iov[] = { 1254 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1255 {.iov_base = data, .iov_len = len} 1256 }; 1257 1258 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1259 len); 1260 set_be_simple_reply(&reply, nbd_err, handle); 1261 1262 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1263 } 1264 1265 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1266 uint16_t type, uint64_t handle, uint32_t length) 1267 { 1268 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1269 stw_be_p(&chunk->flags, flags); 1270 stw_be_p(&chunk->type, type); 1271 stq_be_p(&chunk->handle, handle); 1272 stl_be_p(&chunk->length, length); 1273 } 1274 1275 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1276 uint64_t handle, 1277 uint64_t offset, 1278 void *data, 1279 size_t size, 1280 Error **errp) 1281 { 1282 NBDStructuredRead chunk; 1283 struct iovec iov[] = { 1284 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1285 {.iov_base = data, .iov_len = size} 1286 }; 1287 1288 trace_nbd_co_send_structured_read(handle, offset, data, size); 1289 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_OFFSET_DATA, 1290 handle, sizeof(chunk) - sizeof(chunk.h) + size); 1291 stq_be_p(&chunk.offset, offset); 1292 1293 return nbd_co_send_iov(client, iov, 2, errp); 1294 } 1295 1296 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1297 uint64_t handle, 1298 uint32_t error, 1299 const char *msg, 1300 Error **errp) 1301 { 1302 NBDStructuredError chunk; 1303 int nbd_err = system_errno_to_nbd_errno(error); 1304 struct iovec iov[] = { 1305 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1306 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1307 }; 1308 1309 assert(nbd_err); 1310 trace_nbd_co_send_structured_error(handle, nbd_err, 1311 nbd_err_lookup(nbd_err), msg ? msg : ""); 1312 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1313 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1314 stl_be_p(&chunk.error, nbd_err); 1315 stw_be_p(&chunk.message_length, iov[1].iov_len); 1316 1317 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1318 } 1319 1320 /* nbd_co_receive_request 1321 * Collect a client request. Return 0 if request looks valid, -EIO to drop 1322 * connection right away, and any other negative value to report an error to 1323 * the client (although the caller may still need to disconnect after reporting 1324 * the error). 1325 */ 1326 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 1327 Error **errp) 1328 { 1329 NBDClient *client = req->client; 1330 int valid_flags; 1331 1332 g_assert(qemu_in_coroutine()); 1333 assert(client->recv_coroutine == qemu_coroutine_self()); 1334 if (nbd_receive_request(client->ioc, request, errp) < 0) { 1335 return -EIO; 1336 } 1337 1338 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 1339 nbd_cmd_lookup(request->type)); 1340 1341 if (request->type != NBD_CMD_WRITE) { 1342 /* No payload, we are ready to read the next request. */ 1343 req->complete = true; 1344 } 1345 1346 if (request->type == NBD_CMD_DISC) { 1347 /* Special case: we're going to disconnect without a reply, 1348 * whether or not flags, from, or len are bogus */ 1349 return -EIO; 1350 } 1351 1352 /* Check for sanity in the parameters, part 1. Defer as many 1353 * checks as possible until after reading any NBD_CMD_WRITE 1354 * payload, so we can try and keep the connection alive. */ 1355 if ((request->from + request->len) < request->from) { 1356 error_setg(errp, 1357 "integer overflow detected, you're probably being attacked"); 1358 return -EINVAL; 1359 } 1360 1361 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) { 1362 if (request->len > NBD_MAX_BUFFER_SIZE) { 1363 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1364 request->len, NBD_MAX_BUFFER_SIZE); 1365 return -EINVAL; 1366 } 1367 1368 req->data = blk_try_blockalign(client->exp->blk, request->len); 1369 if (req->data == NULL) { 1370 error_setg(errp, "No memory"); 1371 return -ENOMEM; 1372 } 1373 } 1374 if (request->type == NBD_CMD_WRITE) { 1375 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) { 1376 error_prepend(errp, "reading from socket failed: "); 1377 return -EIO; 1378 } 1379 req->complete = true; 1380 1381 trace_nbd_co_receive_request_payload_received(request->handle, 1382 request->len); 1383 } 1384 1385 /* Sanity checks, part 2. */ 1386 if (request->from + request->len > client->exp->size) { 1387 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 1388 ", Size: %" PRIu64, request->from, request->len, 1389 (uint64_t)client->exp->size); 1390 return request->type == NBD_CMD_WRITE ? -ENOSPC : -EINVAL; 1391 } 1392 valid_flags = NBD_CMD_FLAG_FUA; 1393 if (request->type == NBD_CMD_READ && client->structured_reply) { 1394 valid_flags |= NBD_CMD_FLAG_DF; 1395 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 1396 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 1397 } 1398 if (request->flags & ~valid_flags) { 1399 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 1400 nbd_cmd_lookup(request->type), request->flags); 1401 return -EINVAL; 1402 } 1403 1404 return 0; 1405 } 1406 1407 /* Owns a reference to the NBDClient passed as opaque. */ 1408 static coroutine_fn void nbd_trip(void *opaque) 1409 { 1410 NBDClient *client = opaque; 1411 NBDExport *exp = client->exp; 1412 NBDRequestData *req; 1413 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 1414 int ret; 1415 int flags; 1416 int reply_data_len = 0; 1417 Error *local_err = NULL; 1418 char *msg = NULL; 1419 1420 trace_nbd_trip(); 1421 if (client->closing) { 1422 nbd_client_put(client); 1423 return; 1424 } 1425 1426 req = nbd_request_get(client); 1427 ret = nbd_co_receive_request(req, &request, &local_err); 1428 client->recv_coroutine = NULL; 1429 nbd_client_receive_next_request(client); 1430 if (ret == -EIO) { 1431 goto disconnect; 1432 } 1433 1434 if (ret < 0) { 1435 goto reply; 1436 } 1437 1438 if (client->closing) { 1439 /* 1440 * The client may be closed when we are blocked in 1441 * nbd_co_receive_request() 1442 */ 1443 goto done; 1444 } 1445 1446 switch (request.type) { 1447 case NBD_CMD_READ: 1448 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 1449 if (request.flags & NBD_CMD_FLAG_FUA) { 1450 ret = blk_co_flush(exp->blk); 1451 if (ret < 0) { 1452 error_setg_errno(&local_err, -ret, "flush failed"); 1453 break; 1454 } 1455 } 1456 1457 ret = blk_pread(exp->blk, request.from + exp->dev_offset, 1458 req->data, request.len); 1459 if (ret < 0) { 1460 error_setg_errno(&local_err, -ret, "reading from file failed"); 1461 break; 1462 } 1463 1464 reply_data_len = request.len; 1465 1466 break; 1467 case NBD_CMD_WRITE: 1468 if (exp->nbdflags & NBD_FLAG_READ_ONLY) { 1469 error_setg(&local_err, "Export is read-only"); 1470 ret = -EROFS; 1471 break; 1472 } 1473 1474 flags = 0; 1475 if (request.flags & NBD_CMD_FLAG_FUA) { 1476 flags |= BDRV_REQ_FUA; 1477 } 1478 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset, 1479 req->data, request.len, flags); 1480 if (ret < 0) { 1481 error_setg_errno(&local_err, -ret, "writing to file failed"); 1482 } 1483 1484 break; 1485 case NBD_CMD_WRITE_ZEROES: 1486 if (exp->nbdflags & NBD_FLAG_READ_ONLY) { 1487 error_setg(&local_err, "Export is read-only"); 1488 ret = -EROFS; 1489 break; 1490 } 1491 1492 flags = 0; 1493 if (request.flags & NBD_CMD_FLAG_FUA) { 1494 flags |= BDRV_REQ_FUA; 1495 } 1496 if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) { 1497 flags |= BDRV_REQ_MAY_UNMAP; 1498 } 1499 ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset, 1500 request.len, flags); 1501 if (ret < 0) { 1502 error_setg_errno(&local_err, -ret, "writing to file failed"); 1503 } 1504 1505 break; 1506 case NBD_CMD_DISC: 1507 /* unreachable, thanks to special case in nbd_co_receive_request() */ 1508 abort(); 1509 1510 case NBD_CMD_FLUSH: 1511 ret = blk_co_flush(exp->blk); 1512 if (ret < 0) { 1513 error_setg_errno(&local_err, -ret, "flush failed"); 1514 } 1515 1516 break; 1517 case NBD_CMD_TRIM: 1518 ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset, 1519 request.len); 1520 if (ret < 0) { 1521 error_setg_errno(&local_err, -ret, "discard failed"); 1522 } 1523 1524 break; 1525 default: 1526 error_setg(&local_err, "invalid request type (%" PRIu32 ") received", 1527 request.type); 1528 ret = -EINVAL; 1529 } 1530 1531 reply: 1532 if (local_err) { 1533 /* If we get here, local_err was not a fatal error, and should be sent 1534 * to the client. */ 1535 assert(ret < 0); 1536 msg = g_strdup(error_get_pretty(local_err)); 1537 error_report_err(local_err); 1538 local_err = NULL; 1539 } 1540 1541 if (client->structured_reply && 1542 (ret < 0 || request.type == NBD_CMD_READ)) { 1543 if (ret < 0) { 1544 ret = nbd_co_send_structured_error(req->client, request.handle, 1545 -ret, msg, &local_err); 1546 } else { 1547 ret = nbd_co_send_structured_read(req->client, request.handle, 1548 request.from, req->data, 1549 reply_data_len, &local_err); 1550 } 1551 } else { 1552 ret = nbd_co_send_simple_reply(req->client, request.handle, 1553 ret < 0 ? -ret : 0, 1554 req->data, reply_data_len, &local_err); 1555 } 1556 g_free(msg); 1557 if (ret < 0) { 1558 error_prepend(&local_err, "Failed to send reply: "); 1559 goto disconnect; 1560 } 1561 1562 /* We must disconnect after NBD_CMD_WRITE if we did not 1563 * read the payload. 1564 */ 1565 if (!req->complete) { 1566 error_setg(&local_err, "Request handling failed in intermediate state"); 1567 goto disconnect; 1568 } 1569 1570 done: 1571 nbd_request_put(req); 1572 nbd_client_put(client); 1573 return; 1574 1575 disconnect: 1576 if (local_err) { 1577 error_reportf_err(local_err, "Disconnect client, due to: "); 1578 } 1579 nbd_request_put(req); 1580 client_close(client, true); 1581 nbd_client_put(client); 1582 } 1583 1584 static void nbd_client_receive_next_request(NBDClient *client) 1585 { 1586 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 1587 nbd_client_get(client); 1588 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 1589 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 1590 } 1591 } 1592 1593 static coroutine_fn void nbd_co_client_start(void *opaque) 1594 { 1595 NBDClient *client = opaque; 1596 NBDExport *exp = client->exp; 1597 Error *local_err = NULL; 1598 1599 if (exp) { 1600 nbd_export_get(exp); 1601 QTAILQ_INSERT_TAIL(&exp->clients, client, next); 1602 } 1603 qemu_co_mutex_init(&client->send_lock); 1604 1605 if (nbd_negotiate(client, &local_err)) { 1606 if (local_err) { 1607 error_report_err(local_err); 1608 } 1609 client_close(client, false); 1610 return; 1611 } 1612 1613 nbd_client_receive_next_request(client); 1614 } 1615 1616 /* 1617 * Create a new client listener on the given export @exp, using the 1618 * given channel @sioc. Begin servicing it in a coroutine. When the 1619 * connection closes, call @close_fn with an indication of whether the 1620 * client completed negotiation. 1621 */ 1622 void nbd_client_new(NBDExport *exp, 1623 QIOChannelSocket *sioc, 1624 QCryptoTLSCreds *tlscreds, 1625 const char *tlsaclname, 1626 void (*close_fn)(NBDClient *, bool)) 1627 { 1628 NBDClient *client; 1629 Coroutine *co; 1630 1631 client = g_new0(NBDClient, 1); 1632 client->refcount = 1; 1633 client->exp = exp; 1634 client->tlscreds = tlscreds; 1635 if (tlscreds) { 1636 object_ref(OBJECT(client->tlscreds)); 1637 } 1638 client->tlsaclname = g_strdup(tlsaclname); 1639 client->sioc = sioc; 1640 object_ref(OBJECT(client->sioc)); 1641 client->ioc = QIO_CHANNEL(sioc); 1642 object_ref(OBJECT(client->ioc)); 1643 client->close_fn = close_fn; 1644 1645 co = qemu_coroutine_create(nbd_co_client_start, client); 1646 qemu_coroutine_enter(co); 1647 } 1648