1 /* 2 * Copyright (C) 2016-2018 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 uint32_t opt; /* Current option being negotiated */ 107 uint32_t optlen; /* remaining length of data in ioc for the option being 108 negotiated now */ 109 }; 110 111 static void nbd_client_receive_next_request(NBDClient *client); 112 113 /* Basic flow for negotiation 114 115 Server Client 116 Negotiate 117 118 or 119 120 Server Client 121 Negotiate #1 122 Option 123 Negotiate #2 124 125 ---- 126 127 followed by 128 129 Server Client 130 Request 131 Response 132 Request 133 Response 134 ... 135 ... 136 Request (type == 2) 137 138 */ 139 140 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 141 uint32_t type, uint32_t length) 142 { 143 stq_be_p(&rep->magic, NBD_REP_MAGIC); 144 stl_be_p(&rep->option, option); 145 stl_be_p(&rep->type, type); 146 stl_be_p(&rep->length, length); 147 } 148 149 /* Send a reply header, including length, but no payload. 150 * Return -errno on error, 0 on success. */ 151 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 152 uint32_t len, Error **errp) 153 { 154 NBDOptionReply rep; 155 156 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 157 type, nbd_rep_lookup(type), len); 158 159 assert(len < NBD_MAX_BUFFER_SIZE); 160 161 set_be_option_rep(&rep, client->opt, type, len); 162 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 163 } 164 165 /* Send a reply header with default 0 length. 166 * Return -errno on error, 0 on success. */ 167 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 168 Error **errp) 169 { 170 return nbd_negotiate_send_rep_len(client, type, 0, errp); 171 } 172 173 /* Send an error reply. 174 * Return -errno on error, 0 on success. */ 175 static int GCC_FMT_ATTR(4, 0) 176 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 177 Error **errp, const char *fmt, va_list va) 178 { 179 char *msg; 180 int ret; 181 size_t len; 182 183 msg = g_strdup_vprintf(fmt, va); 184 len = strlen(msg); 185 assert(len < 4096); 186 trace_nbd_negotiate_send_rep_err(msg); 187 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 188 if (ret < 0) { 189 goto out; 190 } 191 if (nbd_write(client->ioc, msg, len, errp) < 0) { 192 error_prepend(errp, "write failed (error message): "); 193 ret = -EIO; 194 } else { 195 ret = 0; 196 } 197 198 out: 199 g_free(msg); 200 return ret; 201 } 202 203 /* Send an error reply. 204 * Return -errno on error, 0 on success. */ 205 static int GCC_FMT_ATTR(4, 5) 206 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 207 Error **errp, const char *fmt, ...) 208 { 209 va_list va; 210 int ret; 211 212 va_start(va, fmt); 213 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 214 va_end(va); 215 return ret; 216 } 217 218 /* Drop remainder of the current option, and send a reply with the 219 * given error type and message. Return -errno on read or write 220 * failure; or 0 if connection is still live. */ 221 static int GCC_FMT_ATTR(4, 5) 222 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 223 const char *fmt, ...) 224 { 225 int ret = nbd_drop(client->ioc, client->optlen, errp); 226 va_list va; 227 228 client->optlen = 0; 229 if (!ret) { 230 va_start(va, fmt); 231 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 232 va_end(va); 233 } 234 return ret; 235 } 236 237 /* Read size bytes from the unparsed payload of the current option. 238 * Return -errno on I/O error, 0 if option was completely handled by 239 * sending a reply about inconsistent lengths, or 1 on success. */ 240 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 241 Error **errp) 242 { 243 if (size > client->optlen) { 244 return nbd_opt_drop(client, NBD_REP_ERR_INVALID, errp, 245 "Inconsistent lengths in option %s", 246 nbd_opt_lookup(client->opt)); 247 } 248 client->optlen -= size; 249 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1; 250 } 251 252 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 253 * Return -errno on error, 0 on success. */ 254 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 255 Error **errp) 256 { 257 size_t name_len, desc_len; 258 uint32_t len; 259 const char *name = exp->name ? exp->name : ""; 260 const char *desc = exp->description ? exp->description : ""; 261 QIOChannel *ioc = client->ioc; 262 int ret; 263 264 trace_nbd_negotiate_send_rep_list(name, desc); 265 name_len = strlen(name); 266 desc_len = strlen(desc); 267 len = name_len + desc_len + sizeof(len); 268 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 269 if (ret < 0) { 270 return ret; 271 } 272 273 len = cpu_to_be32(name_len); 274 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 275 error_prepend(errp, "write failed (name length): "); 276 return -EINVAL; 277 } 278 279 if (nbd_write(ioc, name, name_len, errp) < 0) { 280 error_prepend(errp, "write failed (name buffer): "); 281 return -EINVAL; 282 } 283 284 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 285 error_prepend(errp, "write failed (description buffer): "); 286 return -EINVAL; 287 } 288 289 return 0; 290 } 291 292 /* Process the NBD_OPT_LIST command, with a potential series of replies. 293 * Return -errno on error, 0 on success. */ 294 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 295 { 296 NBDExport *exp; 297 assert(client->opt == NBD_OPT_LIST); 298 299 /* For each export, send a NBD_REP_SERVER reply. */ 300 QTAILQ_FOREACH(exp, &exports, next) { 301 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 302 return -EINVAL; 303 } 304 } 305 /* Finish with a NBD_REP_ACK. */ 306 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 307 } 308 309 /* Send a reply to NBD_OPT_EXPORT_NAME. 310 * Return -errno on error, 0 on success. */ 311 static int nbd_negotiate_handle_export_name(NBDClient *client, 312 uint16_t myflags, bool no_zeroes, 313 Error **errp) 314 { 315 char name[NBD_MAX_NAME_SIZE + 1]; 316 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 317 size_t len; 318 int ret; 319 320 /* Client sends: 321 [20 .. xx] export name (length bytes) 322 Server replies: 323 [ 0 .. 7] size 324 [ 8 .. 9] export flags 325 [10 .. 133] reserved (0) [unless no_zeroes] 326 */ 327 trace_nbd_negotiate_handle_export_name(); 328 if (client->optlen >= sizeof(name)) { 329 error_setg(errp, "Bad length received"); 330 return -EINVAL; 331 } 332 if (nbd_read(client->ioc, name, client->optlen, errp) < 0) { 333 error_prepend(errp, "read failed: "); 334 return -EIO; 335 } 336 name[client->optlen] = '\0'; 337 client->optlen = 0; 338 339 trace_nbd_negotiate_handle_export_name_request(name); 340 341 client->exp = nbd_export_find(name); 342 if (!client->exp) { 343 error_setg(errp, "export not found"); 344 return -EINVAL; 345 } 346 347 trace_nbd_negotiate_new_style_size_flags(client->exp->size, 348 client->exp->nbdflags | myflags); 349 stq_be_p(buf, client->exp->size); 350 stw_be_p(buf + 8, client->exp->nbdflags | myflags); 351 len = no_zeroes ? 10 : sizeof(buf); 352 ret = nbd_write(client->ioc, buf, len, errp); 353 if (ret < 0) { 354 error_prepend(errp, "write failed: "); 355 return ret; 356 } 357 358 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 359 nbd_export_get(client->exp); 360 361 return 0; 362 } 363 364 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 365 * The buffer does NOT include the info type prefix. 366 * Return -errno on error, 0 if ready to send more. */ 367 static int nbd_negotiate_send_info(NBDClient *client, 368 uint16_t info, uint32_t length, void *buf, 369 Error **errp) 370 { 371 int rc; 372 373 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 374 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 375 sizeof(info) + length, errp); 376 if (rc < 0) { 377 return rc; 378 } 379 cpu_to_be16s(&info); 380 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 381 return -EIO; 382 } 383 if (nbd_write(client->ioc, buf, length, errp) < 0) { 384 return -EIO; 385 } 386 return 0; 387 } 388 389 /* nbd_reject_length: Handle any unexpected payload. 390 * @fatal requests that we quit talking to the client, even if we are able 391 * to successfully send an error reply. 392 * Return: 393 * -errno transmission error occurred or @fatal was requested, errp is set 394 * 0 error message successfully sent to client, errp is not set 395 */ 396 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 397 { 398 int ret; 399 400 assert(client->optlen); 401 ret = nbd_opt_drop(client, NBD_REP_ERR_INVALID, errp, 402 "option '%s' has unexpected length", 403 nbd_opt_lookup(client->opt)); 404 if (fatal && !ret) { 405 error_setg(errp, "option '%s' has unexpected length", 406 nbd_opt_lookup(client->opt)); 407 return -EINVAL; 408 } 409 return ret; 410 } 411 412 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 413 * Return -errno on error, 0 if ready for next option, and 1 to move 414 * into transmission phase. */ 415 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags, 416 Error **errp) 417 { 418 int rc; 419 char name[NBD_MAX_NAME_SIZE + 1]; 420 NBDExport *exp; 421 uint16_t requests; 422 uint16_t request; 423 uint32_t namelen; 424 bool sendname = false; 425 bool blocksize = false; 426 uint32_t sizes[3]; 427 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 428 429 /* Client sends: 430 4 bytes: L, name length (can be 0) 431 L bytes: export name 432 2 bytes: N, number of requests (can be 0) 433 N * 2 bytes: N requests 434 */ 435 rc = nbd_opt_read(client, &namelen, sizeof(namelen), errp); 436 if (rc <= 0) { 437 return rc; 438 } 439 be32_to_cpus(&namelen); 440 if (namelen >= sizeof(name)) { 441 return nbd_opt_drop(client, NBD_REP_ERR_INVALID, errp, 442 "name too long for qemu"); 443 } 444 rc = nbd_opt_read(client, name, namelen, errp); 445 if (rc <= 0) { 446 return rc; 447 } 448 name[namelen] = '\0'; 449 trace_nbd_negotiate_handle_export_name_request(name); 450 451 rc = nbd_opt_read(client, &requests, sizeof(requests), errp); 452 if (rc <= 0) { 453 return rc; 454 } 455 be16_to_cpus(&requests); 456 trace_nbd_negotiate_handle_info_requests(requests); 457 while (requests--) { 458 rc = nbd_opt_read(client, &request, sizeof(request), errp); 459 if (rc <= 0) { 460 return rc; 461 } 462 be16_to_cpus(&request); 463 trace_nbd_negotiate_handle_info_request(request, 464 nbd_info_lookup(request)); 465 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 466 * everything else is either a request we don't know or 467 * something we send regardless of request */ 468 switch (request) { 469 case NBD_INFO_NAME: 470 sendname = true; 471 break; 472 case NBD_INFO_BLOCK_SIZE: 473 blocksize = true; 474 break; 475 } 476 } 477 if (client->optlen) { 478 return nbd_reject_length(client, false, errp); 479 } 480 481 exp = nbd_export_find(name); 482 if (!exp) { 483 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 484 errp, "export '%s' not present", 485 name); 486 } 487 488 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 489 if (sendname) { 490 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 491 errp); 492 if (rc < 0) { 493 return rc; 494 } 495 } 496 497 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 498 * client request */ 499 if (exp->description) { 500 size_t len = strlen(exp->description); 501 502 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 503 len, exp->description, errp); 504 if (rc < 0) { 505 return rc; 506 } 507 } 508 509 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 510 * according to whether the client requested it, and according to 511 * whether this is OPT_INFO or OPT_GO. */ 512 /* minimum - 1 for back-compat, or 512 if client is new enough. 513 * TODO: consult blk_bs(blk)->bl.request_alignment? */ 514 sizes[0] = 515 (client->opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1; 516 /* preferred - Hard-code to 4096 for now. 517 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 518 sizes[1] = 4096; 519 /* maximum - At most 32M, but smaller as appropriate. */ 520 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 521 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 522 cpu_to_be32s(&sizes[0]); 523 cpu_to_be32s(&sizes[1]); 524 cpu_to_be32s(&sizes[2]); 525 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 526 sizeof(sizes), sizes, errp); 527 if (rc < 0) { 528 return rc; 529 } 530 531 /* Send NBD_INFO_EXPORT always */ 532 trace_nbd_negotiate_new_style_size_flags(exp->size, 533 exp->nbdflags | myflags); 534 stq_be_p(buf, exp->size); 535 stw_be_p(buf + 8, exp->nbdflags | myflags); 536 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 537 sizeof(buf), buf, errp); 538 if (rc < 0) { 539 return rc; 540 } 541 542 /* If the client is just asking for NBD_OPT_INFO, but forgot to 543 * request block sizes, return an error. 544 * TODO: consult blk_bs(blk)->request_align, and only error if it 545 * is not 1? */ 546 if (client->opt == NBD_OPT_INFO && !blocksize) { 547 return nbd_negotiate_send_rep_err(client, 548 NBD_REP_ERR_BLOCK_SIZE_REQD, 549 errp, 550 "request NBD_INFO_BLOCK_SIZE to " 551 "use this export"); 552 } 553 554 /* Final reply */ 555 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 556 if (rc < 0) { 557 return rc; 558 } 559 560 if (client->opt == NBD_OPT_GO) { 561 client->exp = exp; 562 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 563 nbd_export_get(client->exp); 564 rc = 1; 565 } 566 return rc; 567 } 568 569 570 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 571 * new channel for all further (now-encrypted) communication. */ 572 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 573 Error **errp) 574 { 575 QIOChannel *ioc; 576 QIOChannelTLS *tioc; 577 struct NBDTLSHandshakeData data = { 0 }; 578 579 assert(client->opt == NBD_OPT_STARTTLS); 580 581 trace_nbd_negotiate_handle_starttls(); 582 ioc = client->ioc; 583 584 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 585 return NULL; 586 } 587 588 tioc = qio_channel_tls_new_server(ioc, 589 client->tlscreds, 590 client->tlsaclname, 591 errp); 592 if (!tioc) { 593 return NULL; 594 } 595 596 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 597 trace_nbd_negotiate_handle_starttls_handshake(); 598 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 599 qio_channel_tls_handshake(tioc, 600 nbd_tls_handshake, 601 &data, 602 NULL); 603 604 if (!data.complete) { 605 g_main_loop_run(data.loop); 606 } 607 g_main_loop_unref(data.loop); 608 if (data.error) { 609 object_unref(OBJECT(tioc)); 610 error_propagate(errp, data.error); 611 return NULL; 612 } 613 614 return QIO_CHANNEL(tioc); 615 } 616 617 /* nbd_negotiate_options 618 * Process all NBD_OPT_* client option commands, during fixed newstyle 619 * negotiation. 620 * Return: 621 * -errno on error, errp is set 622 * 0 on successful negotiation, errp is not set 623 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 624 * errp is not set 625 */ 626 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 627 Error **errp) 628 { 629 uint32_t flags; 630 bool fixedNewstyle = false; 631 bool no_zeroes = false; 632 633 /* Client sends: 634 [ 0 .. 3] client flags 635 636 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 637 [ 0 .. 7] NBD_OPTS_MAGIC 638 [ 8 .. 11] NBD option 639 [12 .. 15] Data length 640 ... Rest of request 641 642 [ 0 .. 7] NBD_OPTS_MAGIC 643 [ 8 .. 11] Second NBD option 644 [12 .. 15] Data length 645 ... Rest of request 646 */ 647 648 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) { 649 error_prepend(errp, "read failed: "); 650 return -EIO; 651 } 652 be32_to_cpus(&flags); 653 trace_nbd_negotiate_options_flags(flags); 654 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 655 fixedNewstyle = true; 656 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 657 } 658 if (flags & NBD_FLAG_C_NO_ZEROES) { 659 no_zeroes = true; 660 flags &= ~NBD_FLAG_C_NO_ZEROES; 661 } 662 if (flags != 0) { 663 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 664 return -EINVAL; 665 } 666 667 while (1) { 668 int ret; 669 uint32_t option, length; 670 uint64_t magic; 671 672 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) { 673 error_prepend(errp, "read failed: "); 674 return -EINVAL; 675 } 676 magic = be64_to_cpu(magic); 677 trace_nbd_negotiate_options_check_magic(magic); 678 if (magic != NBD_OPTS_MAGIC) { 679 error_setg(errp, "Bad magic received"); 680 return -EINVAL; 681 } 682 683 if (nbd_read(client->ioc, &option, 684 sizeof(option), errp) < 0) { 685 error_prepend(errp, "read failed: "); 686 return -EINVAL; 687 } 688 option = be32_to_cpu(option); 689 client->opt = option; 690 691 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) { 692 error_prepend(errp, "read failed: "); 693 return -EINVAL; 694 } 695 length = be32_to_cpu(length); 696 assert(!client->optlen); 697 client->optlen = length; 698 699 if (length > NBD_MAX_BUFFER_SIZE) { 700 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 701 length, NBD_MAX_BUFFER_SIZE); 702 return -EINVAL; 703 } 704 705 trace_nbd_negotiate_options_check_option(option, 706 nbd_opt_lookup(option)); 707 if (client->tlscreds && 708 client->ioc == (QIOChannel *)client->sioc) { 709 QIOChannel *tioc; 710 if (!fixedNewstyle) { 711 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 712 return -EINVAL; 713 } 714 switch (option) { 715 case NBD_OPT_STARTTLS: 716 if (length) { 717 /* Unconditionally drop the connection if the client 718 * can't start a TLS negotiation correctly */ 719 return nbd_reject_length(client, true, errp); 720 } 721 tioc = nbd_negotiate_handle_starttls(client, errp); 722 if (!tioc) { 723 return -EIO; 724 } 725 ret = 0; 726 object_unref(OBJECT(client->ioc)); 727 client->ioc = QIO_CHANNEL(tioc); 728 break; 729 730 case NBD_OPT_EXPORT_NAME: 731 /* No way to return an error to client, so drop connection */ 732 error_setg(errp, "Option 0x%x not permitted before TLS", 733 option); 734 return -EINVAL; 735 736 default: 737 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, errp, 738 "Option 0x%" PRIx32 739 "not permitted before TLS", option); 740 /* Let the client keep trying, unless they asked to 741 * quit. In this mode, we've already sent an error, so 742 * we can't ack the abort. */ 743 if (option == NBD_OPT_ABORT) { 744 return 1; 745 } 746 break; 747 } 748 } else if (fixedNewstyle) { 749 switch (option) { 750 case NBD_OPT_LIST: 751 if (length) { 752 ret = nbd_reject_length(client, false, errp); 753 } else { 754 ret = nbd_negotiate_handle_list(client, errp); 755 } 756 break; 757 758 case NBD_OPT_ABORT: 759 /* NBD spec says we must try to reply before 760 * disconnecting, but that we must also tolerate 761 * guests that don't wait for our reply. */ 762 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 763 return 1; 764 765 case NBD_OPT_EXPORT_NAME: 766 return nbd_negotiate_handle_export_name(client, 767 myflags, no_zeroes, 768 errp); 769 770 case NBD_OPT_INFO: 771 case NBD_OPT_GO: 772 ret = nbd_negotiate_handle_info(client, myflags, errp); 773 if (ret == 1) { 774 assert(option == NBD_OPT_GO); 775 return 0; 776 } 777 break; 778 779 case NBD_OPT_STARTTLS: 780 if (length) { 781 ret = nbd_reject_length(client, false, errp); 782 } else if (client->tlscreds) { 783 ret = nbd_negotiate_send_rep_err(client, 784 NBD_REP_ERR_INVALID, errp, 785 "TLS already enabled"); 786 } else { 787 ret = nbd_negotiate_send_rep_err(client, 788 NBD_REP_ERR_POLICY, errp, 789 "TLS not configured"); 790 } 791 break; 792 793 case NBD_OPT_STRUCTURED_REPLY: 794 if (length) { 795 ret = nbd_reject_length(client, false, errp); 796 } else if (client->structured_reply) { 797 ret = nbd_negotiate_send_rep_err( 798 client, NBD_REP_ERR_INVALID, errp, 799 "structured reply already negotiated"); 800 } else { 801 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 802 client->structured_reply = true; 803 myflags |= NBD_FLAG_SEND_DF; 804 } 805 break; 806 807 default: 808 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 809 "Unsupported option 0x%" PRIx32 " (%s)", 810 option, nbd_opt_lookup(option)); 811 break; 812 } 813 } else { 814 /* 815 * If broken new-style we should drop the connection 816 * for anything except NBD_OPT_EXPORT_NAME 817 */ 818 switch (option) { 819 case NBD_OPT_EXPORT_NAME: 820 return nbd_negotiate_handle_export_name(client, 821 myflags, no_zeroes, 822 errp); 823 824 default: 825 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)", 826 option, nbd_opt_lookup(option)); 827 return -EINVAL; 828 } 829 } 830 if (ret < 0) { 831 return ret; 832 } 833 } 834 } 835 836 /* nbd_negotiate 837 * Return: 838 * -errno on error, errp is set 839 * 0 on successful negotiation, errp is not set 840 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 841 * errp is not set 842 */ 843 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 844 { 845 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 846 int ret; 847 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 848 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 849 NBD_FLAG_SEND_WRITE_ZEROES); 850 bool oldStyle; 851 852 /* Old style negotiation header, no room for options 853 [ 0 .. 7] passwd ("NBDMAGIC") 854 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 855 [16 .. 23] size 856 [24 .. 27] export flags (zero-extended) 857 [28 .. 151] reserved (0) 858 859 New style negotiation header, client can send options 860 [ 0 .. 7] passwd ("NBDMAGIC") 861 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 862 [16 .. 17] server flags (0) 863 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 864 */ 865 866 qio_channel_set_blocking(client->ioc, false, NULL); 867 868 trace_nbd_negotiate_begin(); 869 memcpy(buf, "NBDMAGIC", 8); 870 871 oldStyle = client->exp != NULL && !client->tlscreds; 872 if (oldStyle) { 873 trace_nbd_negotiate_old_style(client->exp->size, 874 client->exp->nbdflags | myflags); 875 stq_be_p(buf + 8, NBD_CLIENT_MAGIC); 876 stq_be_p(buf + 16, client->exp->size); 877 stl_be_p(buf + 24, client->exp->nbdflags | myflags); 878 879 if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) { 880 error_prepend(errp, "write failed: "); 881 return -EINVAL; 882 } 883 } else { 884 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 885 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 886 887 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 888 error_prepend(errp, "write failed: "); 889 return -EINVAL; 890 } 891 ret = nbd_negotiate_options(client, myflags, errp); 892 if (ret != 0) { 893 if (ret < 0) { 894 error_prepend(errp, "option negotiation failed: "); 895 } 896 return ret; 897 } 898 } 899 900 assert(!client->optlen); 901 trace_nbd_negotiate_success(); 902 903 return 0; 904 } 905 906 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 907 Error **errp) 908 { 909 uint8_t buf[NBD_REQUEST_SIZE]; 910 uint32_t magic; 911 int ret; 912 913 ret = nbd_read(ioc, buf, sizeof(buf), errp); 914 if (ret < 0) { 915 return ret; 916 } 917 918 /* Request 919 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 920 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 921 [ 6 .. 7] type (NBD_CMD_READ, ...) 922 [ 8 .. 15] handle 923 [16 .. 23] from 924 [24 .. 27] len 925 */ 926 927 magic = ldl_be_p(buf); 928 request->flags = lduw_be_p(buf + 4); 929 request->type = lduw_be_p(buf + 6); 930 request->handle = ldq_be_p(buf + 8); 931 request->from = ldq_be_p(buf + 16); 932 request->len = ldl_be_p(buf + 24); 933 934 trace_nbd_receive_request(magic, request->flags, request->type, 935 request->from, request->len); 936 937 if (magic != NBD_REQUEST_MAGIC) { 938 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 939 return -EINVAL; 940 } 941 return 0; 942 } 943 944 #define MAX_NBD_REQUESTS 16 945 946 void nbd_client_get(NBDClient *client) 947 { 948 client->refcount++; 949 } 950 951 void nbd_client_put(NBDClient *client) 952 { 953 if (--client->refcount == 0) { 954 /* The last reference should be dropped by client->close, 955 * which is called by client_close. 956 */ 957 assert(client->closing); 958 959 qio_channel_detach_aio_context(client->ioc); 960 object_unref(OBJECT(client->sioc)); 961 object_unref(OBJECT(client->ioc)); 962 if (client->tlscreds) { 963 object_unref(OBJECT(client->tlscreds)); 964 } 965 g_free(client->tlsaclname); 966 if (client->exp) { 967 QTAILQ_REMOVE(&client->exp->clients, client, next); 968 nbd_export_put(client->exp); 969 } 970 g_free(client); 971 } 972 } 973 974 static void client_close(NBDClient *client, bool negotiated) 975 { 976 if (client->closing) { 977 return; 978 } 979 980 client->closing = true; 981 982 /* Force requests to finish. They will drop their own references, 983 * then we'll close the socket and free the NBDClient. 984 */ 985 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 986 NULL); 987 988 /* Also tell the client, so that they release their reference. */ 989 if (client->close_fn) { 990 client->close_fn(client, negotiated); 991 } 992 } 993 994 static NBDRequestData *nbd_request_get(NBDClient *client) 995 { 996 NBDRequestData *req; 997 998 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 999 client->nb_requests++; 1000 1001 req = g_new0(NBDRequestData, 1); 1002 nbd_client_get(client); 1003 req->client = client; 1004 return req; 1005 } 1006 1007 static void nbd_request_put(NBDRequestData *req) 1008 { 1009 NBDClient *client = req->client; 1010 1011 if (req->data) { 1012 qemu_vfree(req->data); 1013 } 1014 g_free(req); 1015 1016 client->nb_requests--; 1017 nbd_client_receive_next_request(client); 1018 1019 nbd_client_put(client); 1020 } 1021 1022 static void blk_aio_attached(AioContext *ctx, void *opaque) 1023 { 1024 NBDExport *exp = opaque; 1025 NBDClient *client; 1026 1027 trace_nbd_blk_aio_attached(exp->name, ctx); 1028 1029 exp->ctx = ctx; 1030 1031 QTAILQ_FOREACH(client, &exp->clients, next) { 1032 qio_channel_attach_aio_context(client->ioc, ctx); 1033 if (client->recv_coroutine) { 1034 aio_co_schedule(ctx, client->recv_coroutine); 1035 } 1036 if (client->send_coroutine) { 1037 aio_co_schedule(ctx, client->send_coroutine); 1038 } 1039 } 1040 } 1041 1042 static void blk_aio_detach(void *opaque) 1043 { 1044 NBDExport *exp = opaque; 1045 NBDClient *client; 1046 1047 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1048 1049 QTAILQ_FOREACH(client, &exp->clients, next) { 1050 qio_channel_detach_aio_context(client->ioc); 1051 } 1052 1053 exp->ctx = NULL; 1054 } 1055 1056 static void nbd_eject_notifier(Notifier *n, void *data) 1057 { 1058 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1059 nbd_export_close(exp); 1060 } 1061 1062 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, 1063 uint16_t nbdflags, void (*close)(NBDExport *), 1064 bool writethrough, BlockBackend *on_eject_blk, 1065 Error **errp) 1066 { 1067 AioContext *ctx; 1068 BlockBackend *blk; 1069 NBDExport *exp = g_new0(NBDExport, 1); 1070 uint64_t perm; 1071 int ret; 1072 1073 /* 1074 * NBD exports are used for non-shared storage migration. Make sure 1075 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1076 * access since the export could be available before migration handover. 1077 */ 1078 ctx = bdrv_get_aio_context(bs); 1079 aio_context_acquire(ctx); 1080 bdrv_invalidate_cache(bs, NULL); 1081 aio_context_release(ctx); 1082 1083 /* Don't allow resize while the NBD server is running, otherwise we don't 1084 * care what happens with the node. */ 1085 perm = BLK_PERM_CONSISTENT_READ; 1086 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1087 perm |= BLK_PERM_WRITE; 1088 } 1089 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1090 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1091 ret = blk_insert_bs(blk, bs, errp); 1092 if (ret < 0) { 1093 goto fail; 1094 } 1095 blk_set_enable_write_cache(blk, !writethrough); 1096 1097 exp->refcount = 1; 1098 QTAILQ_INIT(&exp->clients); 1099 exp->blk = blk; 1100 exp->dev_offset = dev_offset; 1101 exp->nbdflags = nbdflags; 1102 exp->size = size < 0 ? blk_getlength(blk) : size; 1103 if (exp->size < 0) { 1104 error_setg_errno(errp, -exp->size, 1105 "Failed to determine the NBD export's length"); 1106 goto fail; 1107 } 1108 exp->size -= exp->size % BDRV_SECTOR_SIZE; 1109 1110 exp->close = close; 1111 exp->ctx = blk_get_aio_context(blk); 1112 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1113 1114 if (on_eject_blk) { 1115 blk_ref(on_eject_blk); 1116 exp->eject_notifier_blk = on_eject_blk; 1117 exp->eject_notifier.notify = nbd_eject_notifier; 1118 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1119 } 1120 return exp; 1121 1122 fail: 1123 blk_unref(blk); 1124 g_free(exp); 1125 return NULL; 1126 } 1127 1128 NBDExport *nbd_export_find(const char *name) 1129 { 1130 NBDExport *exp; 1131 QTAILQ_FOREACH(exp, &exports, next) { 1132 if (strcmp(name, exp->name) == 0) { 1133 return exp; 1134 } 1135 } 1136 1137 return NULL; 1138 } 1139 1140 void nbd_export_set_name(NBDExport *exp, const char *name) 1141 { 1142 if (exp->name == name) { 1143 return; 1144 } 1145 1146 nbd_export_get(exp); 1147 if (exp->name != NULL) { 1148 g_free(exp->name); 1149 exp->name = NULL; 1150 QTAILQ_REMOVE(&exports, exp, next); 1151 nbd_export_put(exp); 1152 } 1153 if (name != NULL) { 1154 nbd_export_get(exp); 1155 exp->name = g_strdup(name); 1156 QTAILQ_INSERT_TAIL(&exports, exp, next); 1157 } 1158 nbd_export_put(exp); 1159 } 1160 1161 void nbd_export_set_description(NBDExport *exp, const char *description) 1162 { 1163 g_free(exp->description); 1164 exp->description = g_strdup(description); 1165 } 1166 1167 void nbd_export_close(NBDExport *exp) 1168 { 1169 NBDClient *client, *next; 1170 1171 nbd_export_get(exp); 1172 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1173 client_close(client, true); 1174 } 1175 nbd_export_set_name(exp, NULL); 1176 nbd_export_set_description(exp, NULL); 1177 nbd_export_put(exp); 1178 } 1179 1180 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1181 { 1182 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1183 nbd_export_close(exp); 1184 return; 1185 } 1186 1187 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1188 1189 error_setg(errp, "export '%s' still in use", exp->name); 1190 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1191 } 1192 1193 void nbd_export_get(NBDExport *exp) 1194 { 1195 assert(exp->refcount > 0); 1196 exp->refcount++; 1197 } 1198 1199 void nbd_export_put(NBDExport *exp) 1200 { 1201 assert(exp->refcount > 0); 1202 if (exp->refcount == 1) { 1203 nbd_export_close(exp); 1204 } 1205 1206 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1207 * if someone calls nbd_export_put() on named export not through 1208 * nbd_export_set_name() when refcount is 1. So, let's assert that 1209 * it is > 0. 1210 */ 1211 assert(exp->refcount > 0); 1212 if (--exp->refcount == 0) { 1213 assert(exp->name == NULL); 1214 assert(exp->description == NULL); 1215 1216 if (exp->close) { 1217 exp->close(exp); 1218 } 1219 1220 if (exp->blk) { 1221 if (exp->eject_notifier_blk) { 1222 notifier_remove(&exp->eject_notifier); 1223 blk_unref(exp->eject_notifier_blk); 1224 } 1225 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1226 blk_aio_detach, exp); 1227 blk_unref(exp->blk); 1228 exp->blk = NULL; 1229 } 1230 1231 g_free(exp); 1232 } 1233 } 1234 1235 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1236 { 1237 return exp->blk; 1238 } 1239 1240 void nbd_export_close_all(void) 1241 { 1242 NBDExport *exp, *next; 1243 1244 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1245 nbd_export_close(exp); 1246 } 1247 } 1248 1249 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1250 unsigned niov, Error **errp) 1251 { 1252 int ret; 1253 1254 g_assert(qemu_in_coroutine()); 1255 qemu_co_mutex_lock(&client->send_lock); 1256 client->send_coroutine = qemu_coroutine_self(); 1257 1258 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1259 1260 client->send_coroutine = NULL; 1261 qemu_co_mutex_unlock(&client->send_lock); 1262 1263 return ret; 1264 } 1265 1266 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1267 uint64_t handle) 1268 { 1269 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1270 stl_be_p(&reply->error, error); 1271 stq_be_p(&reply->handle, handle); 1272 } 1273 1274 static int nbd_co_send_simple_reply(NBDClient *client, 1275 uint64_t handle, 1276 uint32_t error, 1277 void *data, 1278 size_t len, 1279 Error **errp) 1280 { 1281 NBDSimpleReply reply; 1282 int nbd_err = system_errno_to_nbd_errno(error); 1283 struct iovec iov[] = { 1284 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1285 {.iov_base = data, .iov_len = len} 1286 }; 1287 1288 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1289 len); 1290 set_be_simple_reply(&reply, nbd_err, handle); 1291 1292 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1293 } 1294 1295 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1296 uint16_t type, uint64_t handle, uint32_t length) 1297 { 1298 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1299 stw_be_p(&chunk->flags, flags); 1300 stw_be_p(&chunk->type, type); 1301 stq_be_p(&chunk->handle, handle); 1302 stl_be_p(&chunk->length, length); 1303 } 1304 1305 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1306 uint64_t handle, 1307 Error **errp) 1308 { 1309 NBDStructuredReplyChunk chunk; 1310 struct iovec iov[] = { 1311 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1312 }; 1313 1314 trace_nbd_co_send_structured_done(handle); 1315 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1316 1317 return nbd_co_send_iov(client, iov, 1, errp); 1318 } 1319 1320 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1321 uint64_t handle, 1322 uint64_t offset, 1323 void *data, 1324 size_t size, 1325 bool final, 1326 Error **errp) 1327 { 1328 NBDStructuredReadData chunk; 1329 struct iovec iov[] = { 1330 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1331 {.iov_base = data, .iov_len = size} 1332 }; 1333 1334 assert(size); 1335 trace_nbd_co_send_structured_read(handle, offset, data, size); 1336 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1337 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1338 sizeof(chunk) - sizeof(chunk.h) + size); 1339 stq_be_p(&chunk.offset, offset); 1340 1341 return nbd_co_send_iov(client, iov, 2, errp); 1342 } 1343 1344 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1345 uint64_t handle, 1346 uint64_t offset, 1347 uint8_t *data, 1348 size_t size, 1349 Error **errp) 1350 { 1351 int ret = 0; 1352 NBDExport *exp = client->exp; 1353 size_t progress = 0; 1354 1355 while (progress < size) { 1356 int64_t pnum; 1357 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1358 offset + progress, 1359 size - progress, &pnum, NULL, 1360 NULL); 1361 bool final; 1362 1363 if (status < 0) { 1364 error_setg_errno(errp, -status, "unable to check for holes"); 1365 return status; 1366 } 1367 assert(pnum && pnum <= size - progress); 1368 final = progress + pnum == size; 1369 if (status & BDRV_BLOCK_ZERO) { 1370 NBDStructuredReadHole chunk; 1371 struct iovec iov[] = { 1372 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1373 }; 1374 1375 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1376 pnum); 1377 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1378 NBD_REPLY_TYPE_OFFSET_HOLE, 1379 handle, sizeof(chunk) - sizeof(chunk.h)); 1380 stq_be_p(&chunk.offset, offset + progress); 1381 stl_be_p(&chunk.length, pnum); 1382 ret = nbd_co_send_iov(client, iov, 1, errp); 1383 } else { 1384 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1385 data + progress, pnum); 1386 if (ret < 0) { 1387 error_setg_errno(errp, -ret, "reading from file failed"); 1388 break; 1389 } 1390 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1391 data + progress, pnum, final, 1392 errp); 1393 } 1394 1395 if (ret < 0) { 1396 break; 1397 } 1398 progress += pnum; 1399 } 1400 return ret; 1401 } 1402 1403 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1404 uint64_t handle, 1405 uint32_t error, 1406 const char *msg, 1407 Error **errp) 1408 { 1409 NBDStructuredError chunk; 1410 int nbd_err = system_errno_to_nbd_errno(error); 1411 struct iovec iov[] = { 1412 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1413 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1414 }; 1415 1416 assert(nbd_err); 1417 trace_nbd_co_send_structured_error(handle, nbd_err, 1418 nbd_err_lookup(nbd_err), msg ? msg : ""); 1419 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1420 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1421 stl_be_p(&chunk.error, nbd_err); 1422 stw_be_p(&chunk.message_length, iov[1].iov_len); 1423 1424 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1425 } 1426 1427 /* nbd_co_receive_request 1428 * Collect a client request. Return 0 if request looks valid, -EIO to drop 1429 * connection right away, and any other negative value to report an error to 1430 * the client (although the caller may still need to disconnect after reporting 1431 * the error). 1432 */ 1433 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 1434 Error **errp) 1435 { 1436 NBDClient *client = req->client; 1437 int valid_flags; 1438 1439 g_assert(qemu_in_coroutine()); 1440 assert(client->recv_coroutine == qemu_coroutine_self()); 1441 if (nbd_receive_request(client->ioc, request, errp) < 0) { 1442 return -EIO; 1443 } 1444 1445 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 1446 nbd_cmd_lookup(request->type)); 1447 1448 if (request->type != NBD_CMD_WRITE) { 1449 /* No payload, we are ready to read the next request. */ 1450 req->complete = true; 1451 } 1452 1453 if (request->type == NBD_CMD_DISC) { 1454 /* Special case: we're going to disconnect without a reply, 1455 * whether or not flags, from, or len are bogus */ 1456 return -EIO; 1457 } 1458 1459 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) { 1460 if (request->len > NBD_MAX_BUFFER_SIZE) { 1461 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1462 request->len, NBD_MAX_BUFFER_SIZE); 1463 return -EINVAL; 1464 } 1465 1466 req->data = blk_try_blockalign(client->exp->blk, request->len); 1467 if (req->data == NULL) { 1468 error_setg(errp, "No memory"); 1469 return -ENOMEM; 1470 } 1471 } 1472 if (request->type == NBD_CMD_WRITE) { 1473 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) { 1474 error_prepend(errp, "reading from socket failed: "); 1475 return -EIO; 1476 } 1477 req->complete = true; 1478 1479 trace_nbd_co_receive_request_payload_received(request->handle, 1480 request->len); 1481 } 1482 1483 /* Sanity checks. */ 1484 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 1485 (request->type == NBD_CMD_WRITE || 1486 request->type == NBD_CMD_WRITE_ZEROES || 1487 request->type == NBD_CMD_TRIM)) { 1488 error_setg(errp, "Export is read-only"); 1489 return -EROFS; 1490 } 1491 if (request->from > client->exp->size || 1492 request->from + request->len > client->exp->size) { 1493 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 1494 ", Size: %" PRIu64, request->from, request->len, 1495 (uint64_t)client->exp->size); 1496 return (request->type == NBD_CMD_WRITE || 1497 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 1498 } 1499 valid_flags = NBD_CMD_FLAG_FUA; 1500 if (request->type == NBD_CMD_READ && client->structured_reply) { 1501 valid_flags |= NBD_CMD_FLAG_DF; 1502 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 1503 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 1504 } 1505 if (request->flags & ~valid_flags) { 1506 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 1507 nbd_cmd_lookup(request->type), request->flags); 1508 return -EINVAL; 1509 } 1510 1511 return 0; 1512 } 1513 1514 /* Owns a reference to the NBDClient passed as opaque. */ 1515 static coroutine_fn void nbd_trip(void *opaque) 1516 { 1517 NBDClient *client = opaque; 1518 NBDExport *exp = client->exp; 1519 NBDRequestData *req; 1520 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 1521 int ret; 1522 int flags; 1523 int reply_data_len = 0; 1524 Error *local_err = NULL; 1525 char *msg = NULL; 1526 1527 trace_nbd_trip(); 1528 if (client->closing) { 1529 nbd_client_put(client); 1530 return; 1531 } 1532 1533 req = nbd_request_get(client); 1534 ret = nbd_co_receive_request(req, &request, &local_err); 1535 client->recv_coroutine = NULL; 1536 nbd_client_receive_next_request(client); 1537 if (ret == -EIO) { 1538 goto disconnect; 1539 } 1540 1541 if (ret < 0) { 1542 goto reply; 1543 } 1544 1545 if (client->closing) { 1546 /* 1547 * The client may be closed when we are blocked in 1548 * nbd_co_receive_request() 1549 */ 1550 goto done; 1551 } 1552 1553 switch (request.type) { 1554 case NBD_CMD_READ: 1555 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 1556 if (request.flags & NBD_CMD_FLAG_FUA) { 1557 ret = blk_co_flush(exp->blk); 1558 if (ret < 0) { 1559 error_setg_errno(&local_err, -ret, "flush failed"); 1560 break; 1561 } 1562 } 1563 1564 if (client->structured_reply && !(request.flags & NBD_CMD_FLAG_DF) && 1565 request.len) { 1566 ret = nbd_co_send_sparse_read(req->client, request.handle, 1567 request.from, req->data, request.len, 1568 &local_err); 1569 if (ret < 0) { 1570 goto reply; 1571 } 1572 goto done; 1573 } 1574 1575 ret = blk_pread(exp->blk, request.from + exp->dev_offset, 1576 req->data, request.len); 1577 if (ret < 0) { 1578 error_setg_errno(&local_err, -ret, "reading from file failed"); 1579 break; 1580 } 1581 1582 reply_data_len = request.len; 1583 1584 break; 1585 case NBD_CMD_WRITE: 1586 flags = 0; 1587 if (request.flags & NBD_CMD_FLAG_FUA) { 1588 flags |= BDRV_REQ_FUA; 1589 } 1590 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset, 1591 req->data, request.len, flags); 1592 if (ret < 0) { 1593 error_setg_errno(&local_err, -ret, "writing to file failed"); 1594 } 1595 1596 break; 1597 case NBD_CMD_WRITE_ZEROES: 1598 flags = 0; 1599 if (request.flags & NBD_CMD_FLAG_FUA) { 1600 flags |= BDRV_REQ_FUA; 1601 } 1602 if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) { 1603 flags |= BDRV_REQ_MAY_UNMAP; 1604 } 1605 ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset, 1606 request.len, flags); 1607 if (ret < 0) { 1608 error_setg_errno(&local_err, -ret, "writing to file failed"); 1609 } 1610 1611 break; 1612 case NBD_CMD_DISC: 1613 /* unreachable, thanks to special case in nbd_co_receive_request() */ 1614 abort(); 1615 1616 case NBD_CMD_FLUSH: 1617 ret = blk_co_flush(exp->blk); 1618 if (ret < 0) { 1619 error_setg_errno(&local_err, -ret, "flush failed"); 1620 } 1621 1622 break; 1623 case NBD_CMD_TRIM: 1624 ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset, 1625 request.len); 1626 if (ret < 0) { 1627 error_setg_errno(&local_err, -ret, "discard failed"); 1628 } 1629 1630 break; 1631 default: 1632 error_setg(&local_err, "invalid request type (%" PRIu32 ") received", 1633 request.type); 1634 ret = -EINVAL; 1635 } 1636 1637 reply: 1638 if (local_err) { 1639 /* If we get here, local_err was not a fatal error, and should be sent 1640 * to the client. */ 1641 assert(ret < 0); 1642 msg = g_strdup(error_get_pretty(local_err)); 1643 error_report_err(local_err); 1644 local_err = NULL; 1645 } 1646 1647 if (client->structured_reply && 1648 (ret < 0 || request.type == NBD_CMD_READ)) { 1649 if (ret < 0) { 1650 ret = nbd_co_send_structured_error(req->client, request.handle, 1651 -ret, msg, &local_err); 1652 } else if (reply_data_len) { 1653 ret = nbd_co_send_structured_read(req->client, request.handle, 1654 request.from, req->data, 1655 reply_data_len, true, 1656 &local_err); 1657 } else { 1658 ret = nbd_co_send_structured_done(req->client, request.handle, 1659 &local_err); 1660 } 1661 } else { 1662 ret = nbd_co_send_simple_reply(req->client, request.handle, 1663 ret < 0 ? -ret : 0, 1664 req->data, reply_data_len, &local_err); 1665 } 1666 g_free(msg); 1667 if (ret < 0) { 1668 error_prepend(&local_err, "Failed to send reply: "); 1669 goto disconnect; 1670 } 1671 1672 /* We must disconnect after NBD_CMD_WRITE if we did not 1673 * read the payload. 1674 */ 1675 if (!req->complete) { 1676 error_setg(&local_err, "Request handling failed in intermediate state"); 1677 goto disconnect; 1678 } 1679 1680 done: 1681 nbd_request_put(req); 1682 nbd_client_put(client); 1683 return; 1684 1685 disconnect: 1686 if (local_err) { 1687 error_reportf_err(local_err, "Disconnect client, due to: "); 1688 } 1689 nbd_request_put(req); 1690 client_close(client, true); 1691 nbd_client_put(client); 1692 } 1693 1694 static void nbd_client_receive_next_request(NBDClient *client) 1695 { 1696 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 1697 nbd_client_get(client); 1698 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 1699 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 1700 } 1701 } 1702 1703 static coroutine_fn void nbd_co_client_start(void *opaque) 1704 { 1705 NBDClient *client = opaque; 1706 NBDExport *exp = client->exp; 1707 Error *local_err = NULL; 1708 1709 if (exp) { 1710 nbd_export_get(exp); 1711 QTAILQ_INSERT_TAIL(&exp->clients, client, next); 1712 } 1713 qemu_co_mutex_init(&client->send_lock); 1714 1715 if (nbd_negotiate(client, &local_err)) { 1716 if (local_err) { 1717 error_report_err(local_err); 1718 } 1719 client_close(client, false); 1720 return; 1721 } 1722 1723 nbd_client_receive_next_request(client); 1724 } 1725 1726 /* 1727 * Create a new client listener on the given export @exp, using the 1728 * given channel @sioc. Begin servicing it in a coroutine. When the 1729 * connection closes, call @close_fn with an indication of whether the 1730 * client completed negotiation. 1731 */ 1732 void nbd_client_new(NBDExport *exp, 1733 QIOChannelSocket *sioc, 1734 QCryptoTLSCreds *tlscreds, 1735 const char *tlsaclname, 1736 void (*close_fn)(NBDClient *, bool)) 1737 { 1738 NBDClient *client; 1739 Coroutine *co; 1740 1741 client = g_new0(NBDClient, 1); 1742 client->refcount = 1; 1743 client->exp = exp; 1744 client->tlscreds = tlscreds; 1745 if (tlscreds) { 1746 object_ref(OBJECT(client->tlscreds)); 1747 } 1748 client->tlsaclname = g_strdup(tlsaclname); 1749 client->sioc = sioc; 1750 object_ref(OBJECT(client->sioc)); 1751 client->ioc = QIO_CHANNEL(sioc); 1752 object_ref(OBJECT(client->ioc)); 1753 client->close_fn = close_fn; 1754 1755 co = qemu_coroutine_create(nbd_co_client_start, client); 1756 qemu_coroutine_enter(co); 1757 } 1758