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 (namelen >= sizeof(name)) { 390 msg = "name too long for qemu"; 391 goto invalid; 392 } 393 if (nbd_read(client->ioc, name, namelen, errp) < 0) { 394 return -EIO; 395 } 396 name[namelen] = '\0'; 397 length -= namelen; 398 trace_nbd_negotiate_handle_export_name_request(name); 399 400 if (nbd_read(client->ioc, &requests, sizeof(requests), errp) < 0) { 401 return -EIO; 402 } 403 be16_to_cpus(&requests); 404 length -= sizeof(requests); 405 trace_nbd_negotiate_handle_info_requests(requests); 406 if (requests != length / sizeof(request)) { 407 msg = "incorrect number of requests for overall length"; 408 goto invalid; 409 } 410 while (requests--) { 411 if (nbd_read(client->ioc, &request, sizeof(request), errp) < 0) { 412 return -EIO; 413 } 414 be16_to_cpus(&request); 415 length -= sizeof(request); 416 trace_nbd_negotiate_handle_info_request(request, 417 nbd_info_lookup(request)); 418 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 419 * everything else is either a request we don't know or 420 * something we send regardless of request */ 421 switch (request) { 422 case NBD_INFO_NAME: 423 sendname = true; 424 break; 425 case NBD_INFO_BLOCK_SIZE: 426 blocksize = true; 427 break; 428 } 429 } 430 assert(length == 0); 431 432 exp = nbd_export_find(name); 433 if (!exp) { 434 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_UNKNOWN, 435 opt, errp, "export '%s' not present", 436 name); 437 } 438 439 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 440 if (sendname) { 441 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_NAME, namelen, name, 442 errp); 443 if (rc < 0) { 444 return rc; 445 } 446 } 447 448 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 449 * client request */ 450 if (exp->description) { 451 size_t len = strlen(exp->description); 452 453 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_DESCRIPTION, 454 len, exp->description, errp); 455 if (rc < 0) { 456 return rc; 457 } 458 } 459 460 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 461 * according to whether the client requested it, and according to 462 * whether this is OPT_INFO or OPT_GO. */ 463 /* minimum - 1 for back-compat, or 512 if client is new enough. 464 * TODO: consult blk_bs(blk)->bl.request_alignment? */ 465 sizes[0] = (opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1; 466 /* preferred - Hard-code to 4096 for now. 467 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 468 sizes[1] = 4096; 469 /* maximum - At most 32M, but smaller as appropriate. */ 470 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 471 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 472 cpu_to_be32s(&sizes[0]); 473 cpu_to_be32s(&sizes[1]); 474 cpu_to_be32s(&sizes[2]); 475 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_BLOCK_SIZE, 476 sizeof(sizes), sizes, errp); 477 if (rc < 0) { 478 return rc; 479 } 480 481 /* Send NBD_INFO_EXPORT always */ 482 trace_nbd_negotiate_new_style_size_flags(exp->size, 483 exp->nbdflags | myflags); 484 stq_be_p(buf, exp->size); 485 stw_be_p(buf + 8, exp->nbdflags | myflags); 486 rc = nbd_negotiate_send_info(client, opt, NBD_INFO_EXPORT, 487 sizeof(buf), buf, errp); 488 if (rc < 0) { 489 return rc; 490 } 491 492 /* If the client is just asking for NBD_OPT_INFO, but forgot to 493 * request block sizes, return an error. 494 * TODO: consult blk_bs(blk)->request_align, and only error if it 495 * is not 1? */ 496 if (opt == NBD_OPT_INFO && !blocksize) { 497 return nbd_negotiate_send_rep_err(client->ioc, 498 NBD_REP_ERR_BLOCK_SIZE_REQD, opt, 499 errp, 500 "request NBD_INFO_BLOCK_SIZE to " 501 "use this export"); 502 } 503 504 /* Final reply */ 505 rc = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, opt, errp); 506 if (rc < 0) { 507 return rc; 508 } 509 510 if (opt == NBD_OPT_GO) { 511 client->exp = exp; 512 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 513 nbd_export_get(client->exp); 514 rc = 1; 515 } 516 return rc; 517 518 invalid: 519 if (nbd_drop(client->ioc, length, errp) < 0) { 520 return -EIO; 521 } 522 return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, opt, 523 errp, "%s", msg); 524 } 525 526 527 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 528 * new channel for all further (now-encrypted) communication. */ 529 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 530 Error **errp) 531 { 532 QIOChannel *ioc; 533 QIOChannelTLS *tioc; 534 struct NBDTLSHandshakeData data = { 0 }; 535 536 trace_nbd_negotiate_handle_starttls(); 537 ioc = client->ioc; 538 539 if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, 540 NBD_OPT_STARTTLS, errp) < 0) { 541 return NULL; 542 } 543 544 tioc = qio_channel_tls_new_server(ioc, 545 client->tlscreds, 546 client->tlsaclname, 547 errp); 548 if (!tioc) { 549 return NULL; 550 } 551 552 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 553 trace_nbd_negotiate_handle_starttls_handshake(); 554 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 555 qio_channel_tls_handshake(tioc, 556 nbd_tls_handshake, 557 &data, 558 NULL); 559 560 if (!data.complete) { 561 g_main_loop_run(data.loop); 562 } 563 g_main_loop_unref(data.loop); 564 if (data.error) { 565 object_unref(OBJECT(tioc)); 566 error_propagate(errp, data.error); 567 return NULL; 568 } 569 570 return QIO_CHANNEL(tioc); 571 } 572 573 /* nbd_reject_length: Handle any unexpected payload. 574 * @fatal requests that we quit talking to the client, even if we are able 575 * to successfully send an error to the guest. 576 * Return: 577 * -errno transmission error occurred or @fatal was requested, errp is set 578 * 0 error message successfully sent to client, errp is not set 579 */ 580 static int nbd_reject_length(NBDClient *client, uint32_t length, 581 uint32_t option, bool fatal, Error **errp) 582 { 583 int ret; 584 585 assert(length); 586 if (nbd_drop(client->ioc, length, errp) < 0) { 587 return -EIO; 588 } 589 ret = nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, 590 option, errp, 591 "option '%s' should have zero length", 592 nbd_opt_lookup(option)); 593 if (fatal && !ret) { 594 error_setg(errp, "option '%s' should have zero length", 595 nbd_opt_lookup(option)); 596 return -EINVAL; 597 } 598 return ret; 599 } 600 601 /* nbd_negotiate_options 602 * Process all NBD_OPT_* client option commands, during fixed newstyle 603 * negotiation. 604 * Return: 605 * -errno on error, errp is set 606 * 0 on successful negotiation, errp is not set 607 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 608 * errp is not set 609 */ 610 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 611 Error **errp) 612 { 613 uint32_t flags; 614 bool fixedNewstyle = false; 615 bool no_zeroes = false; 616 617 /* Client sends: 618 [ 0 .. 3] client flags 619 620 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 621 [ 0 .. 7] NBD_OPTS_MAGIC 622 [ 8 .. 11] NBD option 623 [12 .. 15] Data length 624 ... Rest of request 625 626 [ 0 .. 7] NBD_OPTS_MAGIC 627 [ 8 .. 11] Second NBD option 628 [12 .. 15] Data length 629 ... Rest of request 630 */ 631 632 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) { 633 error_prepend(errp, "read failed: "); 634 return -EIO; 635 } 636 be32_to_cpus(&flags); 637 trace_nbd_negotiate_options_flags(flags); 638 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 639 fixedNewstyle = true; 640 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 641 } 642 if (flags & NBD_FLAG_C_NO_ZEROES) { 643 no_zeroes = true; 644 flags &= ~NBD_FLAG_C_NO_ZEROES; 645 } 646 if (flags != 0) { 647 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 648 return -EINVAL; 649 } 650 651 while (1) { 652 int ret; 653 uint32_t option, length; 654 uint64_t magic; 655 656 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) { 657 error_prepend(errp, "read failed: "); 658 return -EINVAL; 659 } 660 magic = be64_to_cpu(magic); 661 trace_nbd_negotiate_options_check_magic(magic); 662 if (magic != NBD_OPTS_MAGIC) { 663 error_setg(errp, "Bad magic received"); 664 return -EINVAL; 665 } 666 667 if (nbd_read(client->ioc, &option, 668 sizeof(option), errp) < 0) { 669 error_prepend(errp, "read failed: "); 670 return -EINVAL; 671 } 672 option = be32_to_cpu(option); 673 674 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) { 675 error_prepend(errp, "read failed: "); 676 return -EINVAL; 677 } 678 length = be32_to_cpu(length); 679 680 if (length > NBD_MAX_BUFFER_SIZE) { 681 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 682 length, NBD_MAX_BUFFER_SIZE); 683 return -EINVAL; 684 } 685 686 trace_nbd_negotiate_options_check_option(option, 687 nbd_opt_lookup(option)); 688 if (client->tlscreds && 689 client->ioc == (QIOChannel *)client->sioc) { 690 QIOChannel *tioc; 691 if (!fixedNewstyle) { 692 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 693 return -EINVAL; 694 } 695 switch (option) { 696 case NBD_OPT_STARTTLS: 697 if (length) { 698 /* Unconditionally drop the connection if the client 699 * can't start a TLS negotiation correctly */ 700 return nbd_reject_length(client, length, option, true, 701 errp); 702 } 703 tioc = nbd_negotiate_handle_starttls(client, errp); 704 if (!tioc) { 705 return -EIO; 706 } 707 ret = 0; 708 object_unref(OBJECT(client->ioc)); 709 client->ioc = QIO_CHANNEL(tioc); 710 break; 711 712 case NBD_OPT_EXPORT_NAME: 713 /* No way to return an error to client, so drop connection */ 714 error_setg(errp, "Option 0x%x not permitted before TLS", 715 option); 716 return -EINVAL; 717 718 default: 719 if (nbd_drop(client->ioc, length, errp) < 0) { 720 return -EIO; 721 } 722 ret = nbd_negotiate_send_rep_err(client->ioc, 723 NBD_REP_ERR_TLS_REQD, 724 option, errp, 725 "Option 0x%" PRIx32 726 "not permitted before TLS", 727 option); 728 /* Let the client keep trying, unless they asked to 729 * quit. In this mode, we've already sent an error, so 730 * we can't ack the abort. */ 731 if (option == NBD_OPT_ABORT) { 732 return 1; 733 } 734 break; 735 } 736 } else if (fixedNewstyle) { 737 switch (option) { 738 case NBD_OPT_LIST: 739 if (length) { 740 ret = nbd_reject_length(client, length, option, false, 741 errp); 742 } else { 743 ret = nbd_negotiate_handle_list(client, errp); 744 } 745 break; 746 747 case NBD_OPT_ABORT: 748 /* NBD spec says we must try to reply before 749 * disconnecting, but that we must also tolerate 750 * guests that don't wait for our reply. */ 751 nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, option, NULL); 752 return 1; 753 754 case NBD_OPT_EXPORT_NAME: 755 return nbd_negotiate_handle_export_name(client, length, 756 myflags, no_zeroes, 757 errp); 758 759 case NBD_OPT_INFO: 760 case NBD_OPT_GO: 761 ret = nbd_negotiate_handle_info(client, length, option, 762 myflags, errp); 763 if (ret == 1) { 764 assert(option == NBD_OPT_GO); 765 return 0; 766 } 767 break; 768 769 case NBD_OPT_STARTTLS: 770 if (length) { 771 ret = nbd_reject_length(client, length, option, false, 772 errp); 773 } else if (client->tlscreds) { 774 ret = nbd_negotiate_send_rep_err(client->ioc, 775 NBD_REP_ERR_INVALID, 776 option, errp, 777 "TLS already enabled"); 778 } else { 779 ret = nbd_negotiate_send_rep_err(client->ioc, 780 NBD_REP_ERR_POLICY, 781 option, errp, 782 "TLS not configured"); 783 } 784 break; 785 786 case NBD_OPT_STRUCTURED_REPLY: 787 if (length) { 788 ret = nbd_reject_length(client, length, option, false, 789 errp); 790 } else if (client->structured_reply) { 791 ret = nbd_negotiate_send_rep_err( 792 client->ioc, NBD_REP_ERR_INVALID, option, errp, 793 "structured reply already negotiated"); 794 } else { 795 ret = nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, 796 option, errp); 797 client->structured_reply = true; 798 myflags |= NBD_FLAG_SEND_DF; 799 } 800 break; 801 802 default: 803 if (nbd_drop(client->ioc, length, errp) < 0) { 804 return -EIO; 805 } 806 ret = nbd_negotiate_send_rep_err(client->ioc, 807 NBD_REP_ERR_UNSUP, 808 option, errp, 809 "Unsupported option 0x%" 810 PRIx32 " (%s)", option, 811 nbd_opt_lookup(option)); 812 break; 813 } 814 } else { 815 /* 816 * If broken new-style we should drop the connection 817 * for anything except NBD_OPT_EXPORT_NAME 818 */ 819 switch (option) { 820 case NBD_OPT_EXPORT_NAME: 821 return nbd_negotiate_handle_export_name(client, length, 822 myflags, no_zeroes, 823 errp); 824 825 default: 826 error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)", 827 option, nbd_opt_lookup(option)); 828 return -EINVAL; 829 } 830 } 831 if (ret < 0) { 832 return ret; 833 } 834 } 835 } 836 837 /* nbd_negotiate 838 * Return: 839 * -errno on error, errp is set 840 * 0 on successful negotiation, errp is not set 841 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 842 * errp is not set 843 */ 844 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 845 { 846 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 847 int ret; 848 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 849 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 850 NBD_FLAG_SEND_WRITE_ZEROES); 851 bool oldStyle; 852 853 /* Old style negotiation header, no room for options 854 [ 0 .. 7] passwd ("NBDMAGIC") 855 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 856 [16 .. 23] size 857 [24 .. 27] export flags (zero-extended) 858 [28 .. 151] reserved (0) 859 860 New style negotiation header, client can send options 861 [ 0 .. 7] passwd ("NBDMAGIC") 862 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 863 [16 .. 17] server flags (0) 864 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 865 */ 866 867 qio_channel_set_blocking(client->ioc, false, NULL); 868 869 trace_nbd_negotiate_begin(); 870 memcpy(buf, "NBDMAGIC", 8); 871 872 oldStyle = client->exp != NULL && !client->tlscreds; 873 if (oldStyle) { 874 trace_nbd_negotiate_old_style(client->exp->size, 875 client->exp->nbdflags | myflags); 876 stq_be_p(buf + 8, NBD_CLIENT_MAGIC); 877 stq_be_p(buf + 16, client->exp->size); 878 stl_be_p(buf + 24, client->exp->nbdflags | myflags); 879 880 if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) { 881 error_prepend(errp, "write failed: "); 882 return -EINVAL; 883 } 884 } else { 885 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 886 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 887 888 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 889 error_prepend(errp, "write failed: "); 890 return -EINVAL; 891 } 892 ret = nbd_negotiate_options(client, myflags, errp); 893 if (ret != 0) { 894 if (ret < 0) { 895 error_prepend(errp, "option negotiation failed: "); 896 } 897 return ret; 898 } 899 } 900 901 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_get(NBDExport *exp) 1181 { 1182 assert(exp->refcount > 0); 1183 exp->refcount++; 1184 } 1185 1186 void nbd_export_put(NBDExport *exp) 1187 { 1188 assert(exp->refcount > 0); 1189 if (exp->refcount == 1) { 1190 nbd_export_close(exp); 1191 } 1192 1193 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1194 * if someone calls nbd_export_put() on named export not through 1195 * nbd_export_set_name() when refcount is 1. So, let's assert that 1196 * it is > 0. 1197 */ 1198 assert(exp->refcount > 0); 1199 if (--exp->refcount == 0) { 1200 assert(exp->name == NULL); 1201 assert(exp->description == NULL); 1202 1203 if (exp->close) { 1204 exp->close(exp); 1205 } 1206 1207 if (exp->blk) { 1208 if (exp->eject_notifier_blk) { 1209 notifier_remove(&exp->eject_notifier); 1210 blk_unref(exp->eject_notifier_blk); 1211 } 1212 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1213 blk_aio_detach, exp); 1214 blk_unref(exp->blk); 1215 exp->blk = NULL; 1216 } 1217 1218 g_free(exp); 1219 } 1220 } 1221 1222 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1223 { 1224 return exp->blk; 1225 } 1226 1227 void nbd_export_close_all(void) 1228 { 1229 NBDExport *exp, *next; 1230 1231 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1232 nbd_export_close(exp); 1233 } 1234 } 1235 1236 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1237 unsigned niov, Error **errp) 1238 { 1239 int ret; 1240 1241 g_assert(qemu_in_coroutine()); 1242 qemu_co_mutex_lock(&client->send_lock); 1243 client->send_coroutine = qemu_coroutine_self(); 1244 1245 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1246 1247 client->send_coroutine = NULL; 1248 qemu_co_mutex_unlock(&client->send_lock); 1249 1250 return ret; 1251 } 1252 1253 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1254 uint64_t handle) 1255 { 1256 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1257 stl_be_p(&reply->error, error); 1258 stq_be_p(&reply->handle, handle); 1259 } 1260 1261 static int nbd_co_send_simple_reply(NBDClient *client, 1262 uint64_t handle, 1263 uint32_t error, 1264 void *data, 1265 size_t len, 1266 Error **errp) 1267 { 1268 NBDSimpleReply reply; 1269 int nbd_err = system_errno_to_nbd_errno(error); 1270 struct iovec iov[] = { 1271 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1272 {.iov_base = data, .iov_len = len} 1273 }; 1274 1275 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1276 len); 1277 set_be_simple_reply(&reply, nbd_err, handle); 1278 1279 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1280 } 1281 1282 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1283 uint16_t type, uint64_t handle, uint32_t length) 1284 { 1285 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1286 stw_be_p(&chunk->flags, flags); 1287 stw_be_p(&chunk->type, type); 1288 stq_be_p(&chunk->handle, handle); 1289 stl_be_p(&chunk->length, length); 1290 } 1291 1292 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1293 uint64_t handle, 1294 Error **errp) 1295 { 1296 NBDStructuredReplyChunk chunk; 1297 struct iovec iov[] = { 1298 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1299 }; 1300 1301 trace_nbd_co_send_structured_done(handle); 1302 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1303 1304 return nbd_co_send_iov(client, iov, 1, errp); 1305 } 1306 1307 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1308 uint64_t handle, 1309 uint64_t offset, 1310 void *data, 1311 size_t size, 1312 bool final, 1313 Error **errp) 1314 { 1315 NBDStructuredReadData chunk; 1316 struct iovec iov[] = { 1317 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1318 {.iov_base = data, .iov_len = size} 1319 }; 1320 1321 assert(size); 1322 trace_nbd_co_send_structured_read(handle, offset, data, size); 1323 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1324 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1325 sizeof(chunk) - sizeof(chunk.h) + size); 1326 stq_be_p(&chunk.offset, offset); 1327 1328 return nbd_co_send_iov(client, iov, 2, errp); 1329 } 1330 1331 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1332 uint64_t handle, 1333 uint64_t offset, 1334 uint8_t *data, 1335 size_t size, 1336 Error **errp) 1337 { 1338 int ret = 0; 1339 NBDExport *exp = client->exp; 1340 size_t progress = 0; 1341 1342 while (progress < size) { 1343 int64_t pnum; 1344 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1345 offset + progress, 1346 size - progress, &pnum, NULL, 1347 NULL); 1348 bool final; 1349 1350 if (status < 0) { 1351 error_setg_errno(errp, -status, "unable to check for holes"); 1352 return status; 1353 } 1354 assert(pnum && pnum <= size - progress); 1355 final = progress + pnum == size; 1356 if (status & BDRV_BLOCK_ZERO) { 1357 NBDStructuredReadHole chunk; 1358 struct iovec iov[] = { 1359 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1360 }; 1361 1362 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1363 pnum); 1364 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1365 NBD_REPLY_TYPE_OFFSET_HOLE, 1366 handle, sizeof(chunk) - sizeof(chunk.h)); 1367 stq_be_p(&chunk.offset, offset + progress); 1368 stl_be_p(&chunk.length, pnum); 1369 ret = nbd_co_send_iov(client, iov, 1, errp); 1370 } else { 1371 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1372 data + progress, pnum); 1373 if (ret < 0) { 1374 error_setg_errno(errp, -ret, "reading from file failed"); 1375 break; 1376 } 1377 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1378 data + progress, pnum, final, 1379 errp); 1380 } 1381 1382 if (ret < 0) { 1383 break; 1384 } 1385 progress += pnum; 1386 } 1387 return ret; 1388 } 1389 1390 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1391 uint64_t handle, 1392 uint32_t error, 1393 const char *msg, 1394 Error **errp) 1395 { 1396 NBDStructuredError chunk; 1397 int nbd_err = system_errno_to_nbd_errno(error); 1398 struct iovec iov[] = { 1399 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1400 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1401 }; 1402 1403 assert(nbd_err); 1404 trace_nbd_co_send_structured_error(handle, nbd_err, 1405 nbd_err_lookup(nbd_err), msg ? msg : ""); 1406 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1407 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1408 stl_be_p(&chunk.error, nbd_err); 1409 stw_be_p(&chunk.message_length, iov[1].iov_len); 1410 1411 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1412 } 1413 1414 /* nbd_co_receive_request 1415 * Collect a client request. Return 0 if request looks valid, -EIO to drop 1416 * connection right away, and any other negative value to report an error to 1417 * the client (although the caller may still need to disconnect after reporting 1418 * the error). 1419 */ 1420 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 1421 Error **errp) 1422 { 1423 NBDClient *client = req->client; 1424 int valid_flags; 1425 1426 g_assert(qemu_in_coroutine()); 1427 assert(client->recv_coroutine == qemu_coroutine_self()); 1428 if (nbd_receive_request(client->ioc, request, errp) < 0) { 1429 return -EIO; 1430 } 1431 1432 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 1433 nbd_cmd_lookup(request->type)); 1434 1435 if (request->type != NBD_CMD_WRITE) { 1436 /* No payload, we are ready to read the next request. */ 1437 req->complete = true; 1438 } 1439 1440 if (request->type == NBD_CMD_DISC) { 1441 /* Special case: we're going to disconnect without a reply, 1442 * whether or not flags, from, or len are bogus */ 1443 return -EIO; 1444 } 1445 1446 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) { 1447 if (request->len > NBD_MAX_BUFFER_SIZE) { 1448 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1449 request->len, NBD_MAX_BUFFER_SIZE); 1450 return -EINVAL; 1451 } 1452 1453 req->data = blk_try_blockalign(client->exp->blk, request->len); 1454 if (req->data == NULL) { 1455 error_setg(errp, "No memory"); 1456 return -ENOMEM; 1457 } 1458 } 1459 if (request->type == NBD_CMD_WRITE) { 1460 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) { 1461 error_prepend(errp, "reading from socket failed: "); 1462 return -EIO; 1463 } 1464 req->complete = true; 1465 1466 trace_nbd_co_receive_request_payload_received(request->handle, 1467 request->len); 1468 } 1469 1470 /* Sanity checks. */ 1471 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 1472 (request->type == NBD_CMD_WRITE || 1473 request->type == NBD_CMD_WRITE_ZEROES || 1474 request->type == NBD_CMD_TRIM)) { 1475 error_setg(errp, "Export is read-only"); 1476 return -EROFS; 1477 } 1478 if (request->from > client->exp->size || 1479 request->from + request->len > client->exp->size) { 1480 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 1481 ", Size: %" PRIu64, request->from, request->len, 1482 (uint64_t)client->exp->size); 1483 return (request->type == NBD_CMD_WRITE || 1484 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 1485 } 1486 valid_flags = NBD_CMD_FLAG_FUA; 1487 if (request->type == NBD_CMD_READ && client->structured_reply) { 1488 valid_flags |= NBD_CMD_FLAG_DF; 1489 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 1490 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 1491 } 1492 if (request->flags & ~valid_flags) { 1493 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 1494 nbd_cmd_lookup(request->type), request->flags); 1495 return -EINVAL; 1496 } 1497 1498 return 0; 1499 } 1500 1501 /* Owns a reference to the NBDClient passed as opaque. */ 1502 static coroutine_fn void nbd_trip(void *opaque) 1503 { 1504 NBDClient *client = opaque; 1505 NBDExport *exp = client->exp; 1506 NBDRequestData *req; 1507 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 1508 int ret; 1509 int flags; 1510 int reply_data_len = 0; 1511 Error *local_err = NULL; 1512 char *msg = NULL; 1513 1514 trace_nbd_trip(); 1515 if (client->closing) { 1516 nbd_client_put(client); 1517 return; 1518 } 1519 1520 req = nbd_request_get(client); 1521 ret = nbd_co_receive_request(req, &request, &local_err); 1522 client->recv_coroutine = NULL; 1523 nbd_client_receive_next_request(client); 1524 if (ret == -EIO) { 1525 goto disconnect; 1526 } 1527 1528 if (ret < 0) { 1529 goto reply; 1530 } 1531 1532 if (client->closing) { 1533 /* 1534 * The client may be closed when we are blocked in 1535 * nbd_co_receive_request() 1536 */ 1537 goto done; 1538 } 1539 1540 switch (request.type) { 1541 case NBD_CMD_READ: 1542 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 1543 if (request.flags & NBD_CMD_FLAG_FUA) { 1544 ret = blk_co_flush(exp->blk); 1545 if (ret < 0) { 1546 error_setg_errno(&local_err, -ret, "flush failed"); 1547 break; 1548 } 1549 } 1550 1551 if (client->structured_reply && !(request.flags & NBD_CMD_FLAG_DF) && 1552 request.len) { 1553 ret = nbd_co_send_sparse_read(req->client, request.handle, 1554 request.from, req->data, request.len, 1555 &local_err); 1556 if (ret < 0) { 1557 goto reply; 1558 } 1559 goto done; 1560 } 1561 1562 ret = blk_pread(exp->blk, request.from + exp->dev_offset, 1563 req->data, request.len); 1564 if (ret < 0) { 1565 error_setg_errno(&local_err, -ret, "reading from file failed"); 1566 break; 1567 } 1568 1569 reply_data_len = request.len; 1570 1571 break; 1572 case NBD_CMD_WRITE: 1573 flags = 0; 1574 if (request.flags & NBD_CMD_FLAG_FUA) { 1575 flags |= BDRV_REQ_FUA; 1576 } 1577 ret = blk_pwrite(exp->blk, request.from + exp->dev_offset, 1578 req->data, request.len, flags); 1579 if (ret < 0) { 1580 error_setg_errno(&local_err, -ret, "writing to file failed"); 1581 } 1582 1583 break; 1584 case NBD_CMD_WRITE_ZEROES: 1585 flags = 0; 1586 if (request.flags & NBD_CMD_FLAG_FUA) { 1587 flags |= BDRV_REQ_FUA; 1588 } 1589 if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) { 1590 flags |= BDRV_REQ_MAY_UNMAP; 1591 } 1592 ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset, 1593 request.len, flags); 1594 if (ret < 0) { 1595 error_setg_errno(&local_err, -ret, "writing to file failed"); 1596 } 1597 1598 break; 1599 case NBD_CMD_DISC: 1600 /* unreachable, thanks to special case in nbd_co_receive_request() */ 1601 abort(); 1602 1603 case NBD_CMD_FLUSH: 1604 ret = blk_co_flush(exp->blk); 1605 if (ret < 0) { 1606 error_setg_errno(&local_err, -ret, "flush failed"); 1607 } 1608 1609 break; 1610 case NBD_CMD_TRIM: 1611 ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset, 1612 request.len); 1613 if (ret < 0) { 1614 error_setg_errno(&local_err, -ret, "discard failed"); 1615 } 1616 1617 break; 1618 default: 1619 error_setg(&local_err, "invalid request type (%" PRIu32 ") received", 1620 request.type); 1621 ret = -EINVAL; 1622 } 1623 1624 reply: 1625 if (local_err) { 1626 /* If we get here, local_err was not a fatal error, and should be sent 1627 * to the client. */ 1628 assert(ret < 0); 1629 msg = g_strdup(error_get_pretty(local_err)); 1630 error_report_err(local_err); 1631 local_err = NULL; 1632 } 1633 1634 if (client->structured_reply && 1635 (ret < 0 || request.type == NBD_CMD_READ)) { 1636 if (ret < 0) { 1637 ret = nbd_co_send_structured_error(req->client, request.handle, 1638 -ret, msg, &local_err); 1639 } else if (reply_data_len) { 1640 ret = nbd_co_send_structured_read(req->client, request.handle, 1641 request.from, req->data, 1642 reply_data_len, true, 1643 &local_err); 1644 } else { 1645 ret = nbd_co_send_structured_done(req->client, request.handle, 1646 &local_err); 1647 } 1648 } else { 1649 ret = nbd_co_send_simple_reply(req->client, request.handle, 1650 ret < 0 ? -ret : 0, 1651 req->data, reply_data_len, &local_err); 1652 } 1653 g_free(msg); 1654 if (ret < 0) { 1655 error_prepend(&local_err, "Failed to send reply: "); 1656 goto disconnect; 1657 } 1658 1659 /* We must disconnect after NBD_CMD_WRITE if we did not 1660 * read the payload. 1661 */ 1662 if (!req->complete) { 1663 error_setg(&local_err, "Request handling failed in intermediate state"); 1664 goto disconnect; 1665 } 1666 1667 done: 1668 nbd_request_put(req); 1669 nbd_client_put(client); 1670 return; 1671 1672 disconnect: 1673 if (local_err) { 1674 error_reportf_err(local_err, "Disconnect client, due to: "); 1675 } 1676 nbd_request_put(req); 1677 client_close(client, true); 1678 nbd_client_put(client); 1679 } 1680 1681 static void nbd_client_receive_next_request(NBDClient *client) 1682 { 1683 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 1684 nbd_client_get(client); 1685 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 1686 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 1687 } 1688 } 1689 1690 static coroutine_fn void nbd_co_client_start(void *opaque) 1691 { 1692 NBDClient *client = opaque; 1693 NBDExport *exp = client->exp; 1694 Error *local_err = NULL; 1695 1696 if (exp) { 1697 nbd_export_get(exp); 1698 QTAILQ_INSERT_TAIL(&exp->clients, client, next); 1699 } 1700 qemu_co_mutex_init(&client->send_lock); 1701 1702 if (nbd_negotiate(client, &local_err)) { 1703 if (local_err) { 1704 error_report_err(local_err); 1705 } 1706 client_close(client, false); 1707 return; 1708 } 1709 1710 nbd_client_receive_next_request(client); 1711 } 1712 1713 /* 1714 * Create a new client listener on the given export @exp, using the 1715 * given channel @sioc. Begin servicing it in a coroutine. When the 1716 * connection closes, call @close_fn with an indication of whether the 1717 * client completed negotiation. 1718 */ 1719 void nbd_client_new(NBDExport *exp, 1720 QIOChannelSocket *sioc, 1721 QCryptoTLSCreds *tlscreds, 1722 const char *tlsaclname, 1723 void (*close_fn)(NBDClient *, bool)) 1724 { 1725 NBDClient *client; 1726 Coroutine *co; 1727 1728 client = g_new0(NBDClient, 1); 1729 client->refcount = 1; 1730 client->exp = exp; 1731 client->tlscreds = tlscreds; 1732 if (tlscreds) { 1733 object_ref(OBJECT(client->tlscreds)); 1734 } 1735 client->tlsaclname = g_strdup(tlsaclname); 1736 client->sioc = sioc; 1737 object_ref(OBJECT(client->sioc)); 1738 client->ioc = QIO_CHANNEL(sioc); 1739 object_ref(OBJECT(client->ioc)); 1740 client->close_fn = close_fn; 1741 1742 co = qemu_coroutine_create(nbd_co_client_start, client); 1743 qemu_coroutine_enter(co); 1744 } 1745