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 #define NBD_META_ID_BASE_ALLOCATION 0 26 #define NBD_META_ID_DIRTY_BITMAP 1 27 28 /* NBD_MAX_BITMAP_EXTENTS: 1 mb of extents data. An empirical 29 * constant. If an increase is needed, note that the NBD protocol 30 * recommends no larger than 32 mb, so that the client won't consider 31 * the reply as a denial of service attack. */ 32 #define NBD_MAX_BITMAP_EXTENTS (0x100000 / 8) 33 34 static int system_errno_to_nbd_errno(int err) 35 { 36 switch (err) { 37 case 0: 38 return NBD_SUCCESS; 39 case EPERM: 40 case EROFS: 41 return NBD_EPERM; 42 case EIO: 43 return NBD_EIO; 44 case ENOMEM: 45 return NBD_ENOMEM; 46 #ifdef EDQUOT 47 case EDQUOT: 48 #endif 49 case EFBIG: 50 case ENOSPC: 51 return NBD_ENOSPC; 52 case EOVERFLOW: 53 return NBD_EOVERFLOW; 54 case ESHUTDOWN: 55 return NBD_ESHUTDOWN; 56 case EINVAL: 57 default: 58 return NBD_EINVAL; 59 } 60 } 61 62 /* Definitions for opaque data types */ 63 64 typedef struct NBDRequestData NBDRequestData; 65 66 struct NBDRequestData { 67 QSIMPLEQ_ENTRY(NBDRequestData) entry; 68 NBDClient *client; 69 uint8_t *data; 70 bool complete; 71 }; 72 73 struct NBDExport { 74 int refcount; 75 void (*close)(NBDExport *exp); 76 77 BlockBackend *blk; 78 char *name; 79 char *description; 80 uint64_t dev_offset; 81 uint64_t size; 82 uint16_t nbdflags; 83 QTAILQ_HEAD(, NBDClient) clients; 84 QTAILQ_ENTRY(NBDExport) next; 85 86 AioContext *ctx; 87 88 BlockBackend *eject_notifier_blk; 89 Notifier eject_notifier; 90 91 BdrvDirtyBitmap *export_bitmap; 92 char *export_bitmap_context; 93 }; 94 95 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 96 97 /* NBDExportMetaContexts represents a list of contexts to be exported, 98 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 99 * NBD_OPT_LIST_META_CONTEXT. */ 100 typedef struct NBDExportMetaContexts { 101 NBDExport *exp; 102 bool valid; /* means that negotiation of the option finished without 103 errors */ 104 bool base_allocation; /* export base:allocation context (block status) */ 105 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */ 106 } NBDExportMetaContexts; 107 108 struct NBDClient { 109 int refcount; 110 void (*close_fn)(NBDClient *client, bool negotiated); 111 112 NBDExport *exp; 113 QCryptoTLSCreds *tlscreds; 114 char *tlsauthz; 115 QIOChannelSocket *sioc; /* The underlying data channel */ 116 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 117 118 Coroutine *recv_coroutine; 119 120 CoMutex send_lock; 121 Coroutine *send_coroutine; 122 123 QTAILQ_ENTRY(NBDClient) next; 124 int nb_requests; 125 bool closing; 126 127 bool structured_reply; 128 NBDExportMetaContexts export_meta; 129 130 uint32_t opt; /* Current option being negotiated */ 131 uint32_t optlen; /* remaining length of data in ioc for the option being 132 negotiated now */ 133 }; 134 135 static void nbd_client_receive_next_request(NBDClient *client); 136 137 /* Basic flow for negotiation 138 139 Server Client 140 Negotiate 141 142 or 143 144 Server Client 145 Negotiate #1 146 Option 147 Negotiate #2 148 149 ---- 150 151 followed by 152 153 Server Client 154 Request 155 Response 156 Request 157 Response 158 ... 159 ... 160 Request (type == 2) 161 162 */ 163 164 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 165 uint32_t type, uint32_t length) 166 { 167 stq_be_p(&rep->magic, NBD_REP_MAGIC); 168 stl_be_p(&rep->option, option); 169 stl_be_p(&rep->type, type); 170 stl_be_p(&rep->length, length); 171 } 172 173 /* Send a reply header, including length, but no payload. 174 * Return -errno on error, 0 on success. */ 175 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 176 uint32_t len, Error **errp) 177 { 178 NBDOptionReply rep; 179 180 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 181 type, nbd_rep_lookup(type), len); 182 183 assert(len < NBD_MAX_BUFFER_SIZE); 184 185 set_be_option_rep(&rep, client->opt, type, len); 186 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 187 } 188 189 /* Send a reply header with default 0 length. 190 * Return -errno on error, 0 on success. */ 191 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 192 Error **errp) 193 { 194 return nbd_negotiate_send_rep_len(client, type, 0, errp); 195 } 196 197 /* Send an error reply. 198 * Return -errno on error, 0 on success. */ 199 static int GCC_FMT_ATTR(4, 0) 200 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 201 Error **errp, const char *fmt, va_list va) 202 { 203 char *msg; 204 int ret; 205 size_t len; 206 207 msg = g_strdup_vprintf(fmt, va); 208 len = strlen(msg); 209 assert(len < 4096); 210 trace_nbd_negotiate_send_rep_err(msg); 211 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 212 if (ret < 0) { 213 goto out; 214 } 215 if (nbd_write(client->ioc, msg, len, errp) < 0) { 216 error_prepend(errp, "write failed (error message): "); 217 ret = -EIO; 218 } else { 219 ret = 0; 220 } 221 222 out: 223 g_free(msg); 224 return ret; 225 } 226 227 /* Send an error reply. 228 * Return -errno on error, 0 on success. */ 229 static int GCC_FMT_ATTR(4, 5) 230 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 231 Error **errp, const char *fmt, ...) 232 { 233 va_list va; 234 int ret; 235 236 va_start(va, fmt); 237 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 238 va_end(va); 239 return ret; 240 } 241 242 /* Drop remainder of the current option, and send a reply with the 243 * given error type and message. Return -errno on read or write 244 * failure; or 0 if connection is still live. */ 245 static int GCC_FMT_ATTR(4, 0) 246 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 247 const char *fmt, va_list va) 248 { 249 int ret = nbd_drop(client->ioc, client->optlen, errp); 250 251 client->optlen = 0; 252 if (!ret) { 253 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 254 } 255 return ret; 256 } 257 258 static int GCC_FMT_ATTR(4, 5) 259 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 260 const char *fmt, ...) 261 { 262 int ret; 263 va_list va; 264 265 va_start(va, fmt); 266 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 267 va_end(va); 268 269 return ret; 270 } 271 272 static int GCC_FMT_ATTR(3, 4) 273 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 274 { 275 int ret; 276 va_list va; 277 278 va_start(va, fmt); 279 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 280 va_end(va); 281 282 return ret; 283 } 284 285 /* Read size bytes from the unparsed payload of the current option. 286 * Return -errno on I/O error, 0 if option was completely handled by 287 * sending a reply about inconsistent lengths, or 1 on success. */ 288 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 289 Error **errp) 290 { 291 if (size > client->optlen) { 292 return nbd_opt_invalid(client, errp, 293 "Inconsistent lengths in option %s", 294 nbd_opt_lookup(client->opt)); 295 } 296 client->optlen -= size; 297 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1; 298 } 299 300 /* Drop size bytes from the unparsed payload of the current option. 301 * Return -errno on I/O error, 0 if option was completely handled by 302 * sending a reply about inconsistent lengths, or 1 on success. */ 303 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 304 { 305 if (size > client->optlen) { 306 return nbd_opt_invalid(client, errp, 307 "Inconsistent lengths in option %s", 308 nbd_opt_lookup(client->opt)); 309 } 310 client->optlen -= size; 311 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 312 } 313 314 /* nbd_opt_read_name 315 * 316 * Read a string with the format: 317 * uint32_t len (<= NBD_MAX_NAME_SIZE) 318 * len bytes string (not 0-terminated) 319 * 320 * @name should be enough to store NBD_MAX_NAME_SIZE+1. 321 * If @length is non-null, it will be set to the actual string length. 322 * 323 * Return -errno on I/O error, 0 if option was completely handled by 324 * sending a reply about inconsistent lengths, or 1 on success. 325 */ 326 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length, 327 Error **errp) 328 { 329 int ret; 330 uint32_t len; 331 332 ret = nbd_opt_read(client, &len, sizeof(len), errp); 333 if (ret <= 0) { 334 return ret; 335 } 336 len = cpu_to_be32(len); 337 338 if (len > NBD_MAX_NAME_SIZE) { 339 return nbd_opt_invalid(client, errp, 340 "Invalid name length: %" PRIu32, len); 341 } 342 343 ret = nbd_opt_read(client, name, len, errp); 344 if (ret <= 0) { 345 return ret; 346 } 347 name[len] = '\0'; 348 349 if (length) { 350 *length = len; 351 } 352 353 return 1; 354 } 355 356 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 357 * Return -errno on error, 0 on success. */ 358 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 359 Error **errp) 360 { 361 size_t name_len, desc_len; 362 uint32_t len; 363 const char *name = exp->name ? exp->name : ""; 364 const char *desc = exp->description ? exp->description : ""; 365 QIOChannel *ioc = client->ioc; 366 int ret; 367 368 trace_nbd_negotiate_send_rep_list(name, desc); 369 name_len = strlen(name); 370 desc_len = strlen(desc); 371 len = name_len + desc_len + sizeof(len); 372 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 373 if (ret < 0) { 374 return ret; 375 } 376 377 len = cpu_to_be32(name_len); 378 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 379 error_prepend(errp, "write failed (name length): "); 380 return -EINVAL; 381 } 382 383 if (nbd_write(ioc, name, name_len, errp) < 0) { 384 error_prepend(errp, "write failed (name buffer): "); 385 return -EINVAL; 386 } 387 388 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 389 error_prepend(errp, "write failed (description buffer): "); 390 return -EINVAL; 391 } 392 393 return 0; 394 } 395 396 /* Process the NBD_OPT_LIST command, with a potential series of replies. 397 * Return -errno on error, 0 on success. */ 398 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 399 { 400 NBDExport *exp; 401 assert(client->opt == NBD_OPT_LIST); 402 403 /* For each export, send a NBD_REP_SERVER reply. */ 404 QTAILQ_FOREACH(exp, &exports, next) { 405 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 406 return -EINVAL; 407 } 408 } 409 /* Finish with a NBD_REP_ACK. */ 410 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 411 } 412 413 static void nbd_check_meta_export(NBDClient *client) 414 { 415 client->export_meta.valid &= client->exp == client->export_meta.exp; 416 } 417 418 /* Send a reply to NBD_OPT_EXPORT_NAME. 419 * Return -errno on error, 0 on success. */ 420 static int nbd_negotiate_handle_export_name(NBDClient *client, 421 uint16_t myflags, bool no_zeroes, 422 Error **errp) 423 { 424 char name[NBD_MAX_NAME_SIZE + 1]; 425 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 426 size_t len; 427 int ret; 428 429 /* Client sends: 430 [20 .. xx] export name (length bytes) 431 Server replies: 432 [ 0 .. 7] size 433 [ 8 .. 9] export flags 434 [10 .. 133] reserved (0) [unless no_zeroes] 435 */ 436 trace_nbd_negotiate_handle_export_name(); 437 if (client->optlen >= sizeof(name)) { 438 error_setg(errp, "Bad length received"); 439 return -EINVAL; 440 } 441 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 442 return -EIO; 443 } 444 name[client->optlen] = '\0'; 445 client->optlen = 0; 446 447 trace_nbd_negotiate_handle_export_name_request(name); 448 449 client->exp = nbd_export_find(name); 450 if (!client->exp) { 451 error_setg(errp, "export not found"); 452 return -EINVAL; 453 } 454 455 trace_nbd_negotiate_new_style_size_flags(client->exp->size, 456 client->exp->nbdflags | myflags); 457 stq_be_p(buf, client->exp->size); 458 stw_be_p(buf + 8, client->exp->nbdflags | myflags); 459 len = no_zeroes ? 10 : sizeof(buf); 460 ret = nbd_write(client->ioc, buf, len, errp); 461 if (ret < 0) { 462 error_prepend(errp, "write failed: "); 463 return ret; 464 } 465 466 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 467 nbd_export_get(client->exp); 468 nbd_check_meta_export(client); 469 470 return 0; 471 } 472 473 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 474 * The buffer does NOT include the info type prefix. 475 * Return -errno on error, 0 if ready to send more. */ 476 static int nbd_negotiate_send_info(NBDClient *client, 477 uint16_t info, uint32_t length, void *buf, 478 Error **errp) 479 { 480 int rc; 481 482 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 483 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 484 sizeof(info) + length, errp); 485 if (rc < 0) { 486 return rc; 487 } 488 info = cpu_to_be16(info); 489 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 490 return -EIO; 491 } 492 if (nbd_write(client->ioc, buf, length, errp) < 0) { 493 return -EIO; 494 } 495 return 0; 496 } 497 498 /* nbd_reject_length: Handle any unexpected payload. 499 * @fatal requests that we quit talking to the client, even if we are able 500 * to successfully send an error reply. 501 * Return: 502 * -errno transmission error occurred or @fatal was requested, errp is set 503 * 0 error message successfully sent to client, errp is not set 504 */ 505 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 506 { 507 int ret; 508 509 assert(client->optlen); 510 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 511 nbd_opt_lookup(client->opt)); 512 if (fatal && !ret) { 513 error_setg(errp, "option '%s' has unexpected length", 514 nbd_opt_lookup(client->opt)); 515 return -EINVAL; 516 } 517 return ret; 518 } 519 520 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 521 * Return -errno on error, 0 if ready for next option, and 1 to move 522 * into transmission phase. */ 523 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags, 524 Error **errp) 525 { 526 int rc; 527 char name[NBD_MAX_NAME_SIZE + 1]; 528 NBDExport *exp; 529 uint16_t requests; 530 uint16_t request; 531 uint32_t namelen; 532 bool sendname = false; 533 bool blocksize = false; 534 uint32_t sizes[3]; 535 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 536 537 /* Client sends: 538 4 bytes: L, name length (can be 0) 539 L bytes: export name 540 2 bytes: N, number of requests (can be 0) 541 N * 2 bytes: N requests 542 */ 543 rc = nbd_opt_read_name(client, name, &namelen, errp); 544 if (rc <= 0) { 545 return rc; 546 } 547 trace_nbd_negotiate_handle_export_name_request(name); 548 549 rc = nbd_opt_read(client, &requests, sizeof(requests), errp); 550 if (rc <= 0) { 551 return rc; 552 } 553 requests = be16_to_cpu(requests); 554 trace_nbd_negotiate_handle_info_requests(requests); 555 while (requests--) { 556 rc = nbd_opt_read(client, &request, sizeof(request), errp); 557 if (rc <= 0) { 558 return rc; 559 } 560 request = be16_to_cpu(request); 561 trace_nbd_negotiate_handle_info_request(request, 562 nbd_info_lookup(request)); 563 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 564 * everything else is either a request we don't know or 565 * something we send regardless of request */ 566 switch (request) { 567 case NBD_INFO_NAME: 568 sendname = true; 569 break; 570 case NBD_INFO_BLOCK_SIZE: 571 blocksize = true; 572 break; 573 } 574 } 575 if (client->optlen) { 576 return nbd_reject_length(client, false, errp); 577 } 578 579 exp = nbd_export_find(name); 580 if (!exp) { 581 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 582 errp, "export '%s' not present", 583 name); 584 } 585 586 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 587 if (sendname) { 588 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 589 errp); 590 if (rc < 0) { 591 return rc; 592 } 593 } 594 595 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 596 * client request */ 597 if (exp->description) { 598 size_t len = strlen(exp->description); 599 600 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 601 len, exp->description, errp); 602 if (rc < 0) { 603 return rc; 604 } 605 } 606 607 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 608 * according to whether the client requested it, and according to 609 * whether this is OPT_INFO or OPT_GO. */ 610 /* minimum - 1 for back-compat, or actual if client will obey it. */ 611 if (client->opt == NBD_OPT_INFO || blocksize) { 612 sizes[0] = blk_get_request_alignment(exp->blk); 613 } else { 614 sizes[0] = 1; 615 } 616 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 617 /* preferred - Hard-code to 4096 for now. 618 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 619 sizes[1] = MAX(4096, sizes[0]); 620 /* maximum - At most 32M, but smaller as appropriate. */ 621 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 622 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 623 sizes[0] = cpu_to_be32(sizes[0]); 624 sizes[1] = cpu_to_be32(sizes[1]); 625 sizes[2] = cpu_to_be32(sizes[2]); 626 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 627 sizeof(sizes), sizes, errp); 628 if (rc < 0) { 629 return rc; 630 } 631 632 /* Send NBD_INFO_EXPORT always */ 633 trace_nbd_negotiate_new_style_size_flags(exp->size, 634 exp->nbdflags | myflags); 635 stq_be_p(buf, exp->size); 636 stw_be_p(buf + 8, exp->nbdflags | myflags); 637 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 638 sizeof(buf), buf, errp); 639 if (rc < 0) { 640 return rc; 641 } 642 643 /* If the client is just asking for NBD_OPT_INFO, but forgot to 644 * request block sizes, return an error. 645 * TODO: consult blk_bs(blk)->request_align, and only error if it 646 * is not 1? */ 647 if (client->opt == NBD_OPT_INFO && !blocksize) { 648 return nbd_negotiate_send_rep_err(client, 649 NBD_REP_ERR_BLOCK_SIZE_REQD, 650 errp, 651 "request NBD_INFO_BLOCK_SIZE to " 652 "use this export"); 653 } 654 655 /* Final reply */ 656 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 657 if (rc < 0) { 658 return rc; 659 } 660 661 if (client->opt == NBD_OPT_GO) { 662 client->exp = exp; 663 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 664 nbd_export_get(client->exp); 665 nbd_check_meta_export(client); 666 rc = 1; 667 } 668 return rc; 669 } 670 671 672 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 673 * new channel for all further (now-encrypted) communication. */ 674 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 675 Error **errp) 676 { 677 QIOChannel *ioc; 678 QIOChannelTLS *tioc; 679 struct NBDTLSHandshakeData data = { 0 }; 680 681 assert(client->opt == NBD_OPT_STARTTLS); 682 683 trace_nbd_negotiate_handle_starttls(); 684 ioc = client->ioc; 685 686 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 687 return NULL; 688 } 689 690 tioc = qio_channel_tls_new_server(ioc, 691 client->tlscreds, 692 client->tlsauthz, 693 errp); 694 if (!tioc) { 695 return NULL; 696 } 697 698 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 699 trace_nbd_negotiate_handle_starttls_handshake(); 700 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 701 qio_channel_tls_handshake(tioc, 702 nbd_tls_handshake, 703 &data, 704 NULL, 705 NULL); 706 707 if (!data.complete) { 708 g_main_loop_run(data.loop); 709 } 710 g_main_loop_unref(data.loop); 711 if (data.error) { 712 object_unref(OBJECT(tioc)); 713 error_propagate(errp, data.error); 714 return NULL; 715 } 716 717 return QIO_CHANNEL(tioc); 718 } 719 720 /* nbd_negotiate_send_meta_context 721 * 722 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 723 * 724 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 725 */ 726 static int nbd_negotiate_send_meta_context(NBDClient *client, 727 const char *context, 728 uint32_t context_id, 729 Error **errp) 730 { 731 NBDOptionReplyMetaContext opt; 732 struct iovec iov[] = { 733 {.iov_base = &opt, .iov_len = sizeof(opt)}, 734 {.iov_base = (void *)context, .iov_len = strlen(context)} 735 }; 736 737 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 738 context_id = 0; 739 } 740 741 trace_nbd_negotiate_meta_query_reply(context, context_id); 742 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 743 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 744 stl_be_p(&opt.context_id, context_id); 745 746 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 747 } 748 749 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern. 750 * @match is never set to false. 751 * 752 * Return -errno on I/O error, 0 if option was completely handled by 753 * sending a reply about inconsistent lengths, or 1 on success. 754 * 755 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 756 * It only means that there are no errors. 757 */ 758 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match, 759 Error **errp) 760 { 761 int ret; 762 char *query; 763 size_t len = strlen(pattern); 764 765 assert(len); 766 767 query = g_malloc(len); 768 ret = nbd_opt_read(client, query, len, errp); 769 if (ret <= 0) { 770 g_free(query); 771 return ret; 772 } 773 774 if (strncmp(query, pattern, len) == 0) { 775 trace_nbd_negotiate_meta_query_parse(pattern); 776 *match = true; 777 } else { 778 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 779 } 780 g_free(query); 781 782 return 1; 783 } 784 785 /* 786 * Read @len bytes, and set @match to true if they match @pattern, or if @len 787 * is 0 and the client is performing _LIST_. @match is never set to false. 788 * 789 * Return -errno on I/O error, 0 if option was completely handled by 790 * sending a reply about inconsistent lengths, or 1 on success. 791 * 792 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 793 * It only means that there are no errors. 794 */ 795 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 796 uint32_t len, bool *match, Error **errp) 797 { 798 if (len == 0) { 799 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 800 *match = true; 801 } 802 trace_nbd_negotiate_meta_query_parse("empty"); 803 return 1; 804 } 805 806 if (len != strlen(pattern)) { 807 trace_nbd_negotiate_meta_query_skip("different lengths"); 808 return nbd_opt_skip(client, len, errp); 809 } 810 811 return nbd_meta_pattern(client, pattern, match, errp); 812 } 813 814 /* nbd_meta_base_query 815 * 816 * Handle queries to 'base' namespace. For now, only the base:allocation 817 * context is available. 'len' is the amount of text remaining to be read from 818 * the current name, after the 'base:' portion has been stripped. 819 * 820 * Return -errno on I/O error, 0 if option was completely handled by 821 * sending a reply about inconsistent lengths, or 1 on success. 822 */ 823 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 824 uint32_t len, Error **errp) 825 { 826 return nbd_meta_empty_or_pattern(client, "allocation", len, 827 &meta->base_allocation, errp); 828 } 829 830 /* nbd_meta_bitmap_query 831 * 832 * Handle query to 'qemu:' namespace. 833 * @len is the amount of text remaining to be read from the current name, after 834 * the 'qemu:' portion has been stripped. 835 * 836 * Return -errno on I/O error, 0 if option was completely handled by 837 * sending a reply about inconsistent lengths, or 1 on success. */ 838 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 839 uint32_t len, Error **errp) 840 { 841 bool dirty_bitmap = false; 842 size_t dirty_bitmap_len = strlen("dirty-bitmap:"); 843 int ret; 844 845 if (!meta->exp->export_bitmap) { 846 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); 847 return nbd_opt_skip(client, len, errp); 848 } 849 850 if (len == 0) { 851 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 852 meta->bitmap = true; 853 } 854 trace_nbd_negotiate_meta_query_parse("empty"); 855 return 1; 856 } 857 858 if (len < dirty_bitmap_len) { 859 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 860 return nbd_opt_skip(client, len, errp); 861 } 862 863 len -= dirty_bitmap_len; 864 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); 865 if (ret <= 0) { 866 return ret; 867 } 868 if (!dirty_bitmap) { 869 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 870 return nbd_opt_skip(client, len, errp); 871 } 872 873 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 874 875 return nbd_meta_empty_or_pattern( 876 client, meta->exp->export_bitmap_context + 877 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp); 878 } 879 880 /* nbd_negotiate_meta_query 881 * 882 * Parse namespace name and call corresponding function to parse body of the 883 * query. 884 * 885 * The only supported namespace now is 'base'. 886 * 887 * The function aims not wasting time and memory to read long unknown namespace 888 * names. 889 * 890 * Return -errno on I/O error, 0 if option was completely handled by 891 * sending a reply about inconsistent lengths, or 1 on success. */ 892 static int nbd_negotiate_meta_query(NBDClient *client, 893 NBDExportMetaContexts *meta, Error **errp) 894 { 895 /* 896 * Both 'qemu' and 'base' namespaces have length = 5 including a 897 * colon. If another length namespace is later introduced, this 898 * should certainly be refactored. 899 */ 900 int ret; 901 size_t ns_len = 5; 902 char ns[5]; 903 uint32_t len; 904 905 ret = nbd_opt_read(client, &len, sizeof(len), errp); 906 if (ret <= 0) { 907 return ret; 908 } 909 len = cpu_to_be32(len); 910 911 if (len < ns_len) { 912 trace_nbd_negotiate_meta_query_skip("length too short"); 913 return nbd_opt_skip(client, len, errp); 914 } 915 916 len -= ns_len; 917 ret = nbd_opt_read(client, ns, ns_len, errp); 918 if (ret <= 0) { 919 return ret; 920 } 921 922 if (!strncmp(ns, "base:", ns_len)) { 923 trace_nbd_negotiate_meta_query_parse("base:"); 924 return nbd_meta_base_query(client, meta, len, errp); 925 } else if (!strncmp(ns, "qemu:", ns_len)) { 926 trace_nbd_negotiate_meta_query_parse("qemu:"); 927 return nbd_meta_qemu_query(client, meta, len, errp); 928 } 929 930 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 931 return nbd_opt_skip(client, len, errp); 932 } 933 934 /* nbd_negotiate_meta_queries 935 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 936 * 937 * Return -errno on I/O error, or 0 if option was completely handled. */ 938 static int nbd_negotiate_meta_queries(NBDClient *client, 939 NBDExportMetaContexts *meta, Error **errp) 940 { 941 int ret; 942 char export_name[NBD_MAX_NAME_SIZE + 1]; 943 NBDExportMetaContexts local_meta; 944 uint32_t nb_queries; 945 int i; 946 947 if (!client->structured_reply) { 948 return nbd_opt_invalid(client, errp, 949 "request option '%s' when structured reply " 950 "is not negotiated", 951 nbd_opt_lookup(client->opt)); 952 } 953 954 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 955 /* Only change the caller's meta on SET. */ 956 meta = &local_meta; 957 } 958 959 memset(meta, 0, sizeof(*meta)); 960 961 ret = nbd_opt_read_name(client, export_name, NULL, errp); 962 if (ret <= 0) { 963 return ret; 964 } 965 966 meta->exp = nbd_export_find(export_name); 967 if (meta->exp == NULL) { 968 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 969 "export '%s' not present", export_name); 970 } 971 972 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); 973 if (ret <= 0) { 974 return ret; 975 } 976 nb_queries = cpu_to_be32(nb_queries); 977 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 978 export_name, nb_queries); 979 980 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 981 /* enable all known contexts */ 982 meta->base_allocation = true; 983 meta->bitmap = !!meta->exp->export_bitmap; 984 } else { 985 for (i = 0; i < nb_queries; ++i) { 986 ret = nbd_negotiate_meta_query(client, meta, errp); 987 if (ret <= 0) { 988 return ret; 989 } 990 } 991 } 992 993 if (meta->base_allocation) { 994 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 995 NBD_META_ID_BASE_ALLOCATION, 996 errp); 997 if (ret < 0) { 998 return ret; 999 } 1000 } 1001 1002 if (meta->bitmap) { 1003 ret = nbd_negotiate_send_meta_context(client, 1004 meta->exp->export_bitmap_context, 1005 NBD_META_ID_DIRTY_BITMAP, 1006 errp); 1007 if (ret < 0) { 1008 return ret; 1009 } 1010 } 1011 1012 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1013 if (ret == 0) { 1014 meta->valid = true; 1015 } 1016 1017 return ret; 1018 } 1019 1020 /* nbd_negotiate_options 1021 * Process all NBD_OPT_* client option commands, during fixed newstyle 1022 * negotiation. 1023 * Return: 1024 * -errno on error, errp is set 1025 * 0 on successful negotiation, errp is not set 1026 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1027 * errp is not set 1028 */ 1029 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags, 1030 Error **errp) 1031 { 1032 uint32_t flags; 1033 bool fixedNewstyle = false; 1034 bool no_zeroes = false; 1035 1036 /* Client sends: 1037 [ 0 .. 3] client flags 1038 1039 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1040 [ 0 .. 7] NBD_OPTS_MAGIC 1041 [ 8 .. 11] NBD option 1042 [12 .. 15] Data length 1043 ... Rest of request 1044 1045 [ 0 .. 7] NBD_OPTS_MAGIC 1046 [ 8 .. 11] Second NBD option 1047 [12 .. 15] Data length 1048 ... Rest of request 1049 */ 1050 1051 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1052 return -EIO; 1053 } 1054 trace_nbd_negotiate_options_flags(flags); 1055 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1056 fixedNewstyle = true; 1057 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1058 } 1059 if (flags & NBD_FLAG_C_NO_ZEROES) { 1060 no_zeroes = true; 1061 flags &= ~NBD_FLAG_C_NO_ZEROES; 1062 } 1063 if (flags != 0) { 1064 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1065 return -EINVAL; 1066 } 1067 1068 while (1) { 1069 int ret; 1070 uint32_t option, length; 1071 uint64_t magic; 1072 1073 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1074 return -EINVAL; 1075 } 1076 trace_nbd_negotiate_options_check_magic(magic); 1077 if (magic != NBD_OPTS_MAGIC) { 1078 error_setg(errp, "Bad magic received"); 1079 return -EINVAL; 1080 } 1081 1082 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1083 return -EINVAL; 1084 } 1085 client->opt = option; 1086 1087 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1088 return -EINVAL; 1089 } 1090 assert(!client->optlen); 1091 client->optlen = length; 1092 1093 if (length > NBD_MAX_BUFFER_SIZE) { 1094 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1095 length, NBD_MAX_BUFFER_SIZE); 1096 return -EINVAL; 1097 } 1098 1099 trace_nbd_negotiate_options_check_option(option, 1100 nbd_opt_lookup(option)); 1101 if (client->tlscreds && 1102 client->ioc == (QIOChannel *)client->sioc) { 1103 QIOChannel *tioc; 1104 if (!fixedNewstyle) { 1105 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1106 return -EINVAL; 1107 } 1108 switch (option) { 1109 case NBD_OPT_STARTTLS: 1110 if (length) { 1111 /* Unconditionally drop the connection if the client 1112 * can't start a TLS negotiation correctly */ 1113 return nbd_reject_length(client, true, errp); 1114 } 1115 tioc = nbd_negotiate_handle_starttls(client, errp); 1116 if (!tioc) { 1117 return -EIO; 1118 } 1119 ret = 0; 1120 object_unref(OBJECT(client->ioc)); 1121 client->ioc = QIO_CHANNEL(tioc); 1122 break; 1123 1124 case NBD_OPT_EXPORT_NAME: 1125 /* No way to return an error to client, so drop connection */ 1126 error_setg(errp, "Option 0x%x not permitted before TLS", 1127 option); 1128 return -EINVAL; 1129 1130 default: 1131 /* Let the client keep trying, unless they asked to 1132 * quit. Always try to give an error back to the 1133 * client; but when replying to OPT_ABORT, be aware 1134 * that the client may hang up before receiving the 1135 * error, in which case we are fine ignoring the 1136 * resulting EPIPE. */ 1137 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1138 option == NBD_OPT_ABORT ? NULL : errp, 1139 "Option 0x%" PRIx32 1140 " not permitted before TLS", option); 1141 if (option == NBD_OPT_ABORT) { 1142 return 1; 1143 } 1144 break; 1145 } 1146 } else if (fixedNewstyle) { 1147 switch (option) { 1148 case NBD_OPT_LIST: 1149 if (length) { 1150 ret = nbd_reject_length(client, false, errp); 1151 } else { 1152 ret = nbd_negotiate_handle_list(client, errp); 1153 } 1154 break; 1155 1156 case NBD_OPT_ABORT: 1157 /* NBD spec says we must try to reply before 1158 * disconnecting, but that we must also tolerate 1159 * guests that don't wait for our reply. */ 1160 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1161 return 1; 1162 1163 case NBD_OPT_EXPORT_NAME: 1164 return nbd_negotiate_handle_export_name(client, 1165 myflags, no_zeroes, 1166 errp); 1167 1168 case NBD_OPT_INFO: 1169 case NBD_OPT_GO: 1170 ret = nbd_negotiate_handle_info(client, myflags, errp); 1171 if (ret == 1) { 1172 assert(option == NBD_OPT_GO); 1173 return 0; 1174 } 1175 break; 1176 1177 case NBD_OPT_STARTTLS: 1178 if (length) { 1179 ret = nbd_reject_length(client, false, errp); 1180 } else if (client->tlscreds) { 1181 ret = nbd_negotiate_send_rep_err(client, 1182 NBD_REP_ERR_INVALID, errp, 1183 "TLS already enabled"); 1184 } else { 1185 ret = nbd_negotiate_send_rep_err(client, 1186 NBD_REP_ERR_POLICY, errp, 1187 "TLS not configured"); 1188 } 1189 break; 1190 1191 case NBD_OPT_STRUCTURED_REPLY: 1192 if (length) { 1193 ret = nbd_reject_length(client, false, errp); 1194 } else if (client->structured_reply) { 1195 ret = nbd_negotiate_send_rep_err( 1196 client, NBD_REP_ERR_INVALID, errp, 1197 "structured reply already negotiated"); 1198 } else { 1199 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1200 client->structured_reply = true; 1201 myflags |= NBD_FLAG_SEND_DF; 1202 } 1203 break; 1204 1205 case NBD_OPT_LIST_META_CONTEXT: 1206 case NBD_OPT_SET_META_CONTEXT: 1207 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1208 errp); 1209 break; 1210 1211 default: 1212 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1213 "Unsupported option %" PRIu32 " (%s)", 1214 option, nbd_opt_lookup(option)); 1215 break; 1216 } 1217 } else { 1218 /* 1219 * If broken new-style we should drop the connection 1220 * for anything except NBD_OPT_EXPORT_NAME 1221 */ 1222 switch (option) { 1223 case NBD_OPT_EXPORT_NAME: 1224 return nbd_negotiate_handle_export_name(client, 1225 myflags, no_zeroes, 1226 errp); 1227 1228 default: 1229 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1230 option, nbd_opt_lookup(option)); 1231 return -EINVAL; 1232 } 1233 } 1234 if (ret < 0) { 1235 return ret; 1236 } 1237 } 1238 } 1239 1240 /* nbd_negotiate 1241 * Return: 1242 * -errno on error, errp is set 1243 * 0 on successful negotiation, errp is not set 1244 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1245 * errp is not set 1246 */ 1247 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1248 { 1249 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1250 int ret; 1251 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | 1252 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA | 1253 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE); 1254 1255 /* Old style negotiation header, no room for options 1256 [ 0 .. 7] passwd ("NBDMAGIC") 1257 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1258 [16 .. 23] size 1259 [24 .. 27] export flags (zero-extended) 1260 [28 .. 151] reserved (0) 1261 1262 New style negotiation header, client can send options 1263 [ 0 .. 7] passwd ("NBDMAGIC") 1264 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1265 [16 .. 17] server flags (0) 1266 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1267 */ 1268 1269 qio_channel_set_blocking(client->ioc, false, NULL); 1270 1271 trace_nbd_negotiate_begin(); 1272 memcpy(buf, "NBDMAGIC", 8); 1273 1274 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1275 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1276 1277 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1278 error_prepend(errp, "write failed: "); 1279 return -EINVAL; 1280 } 1281 ret = nbd_negotiate_options(client, myflags, errp); 1282 if (ret != 0) { 1283 if (ret < 0) { 1284 error_prepend(errp, "option negotiation failed: "); 1285 } 1286 return ret; 1287 } 1288 1289 assert(!client->optlen); 1290 trace_nbd_negotiate_success(); 1291 1292 return 0; 1293 } 1294 1295 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1296 Error **errp) 1297 { 1298 uint8_t buf[NBD_REQUEST_SIZE]; 1299 uint32_t magic; 1300 int ret; 1301 1302 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1303 if (ret < 0) { 1304 return ret; 1305 } 1306 1307 /* Request 1308 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1309 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1310 [ 6 .. 7] type (NBD_CMD_READ, ...) 1311 [ 8 .. 15] handle 1312 [16 .. 23] from 1313 [24 .. 27] len 1314 */ 1315 1316 magic = ldl_be_p(buf); 1317 request->flags = lduw_be_p(buf + 4); 1318 request->type = lduw_be_p(buf + 6); 1319 request->handle = ldq_be_p(buf + 8); 1320 request->from = ldq_be_p(buf + 16); 1321 request->len = ldl_be_p(buf + 24); 1322 1323 trace_nbd_receive_request(magic, request->flags, request->type, 1324 request->from, request->len); 1325 1326 if (magic != NBD_REQUEST_MAGIC) { 1327 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1328 return -EINVAL; 1329 } 1330 return 0; 1331 } 1332 1333 #define MAX_NBD_REQUESTS 16 1334 1335 void nbd_client_get(NBDClient *client) 1336 { 1337 client->refcount++; 1338 } 1339 1340 void nbd_client_put(NBDClient *client) 1341 { 1342 if (--client->refcount == 0) { 1343 /* The last reference should be dropped by client->close, 1344 * which is called by client_close. 1345 */ 1346 assert(client->closing); 1347 1348 qio_channel_detach_aio_context(client->ioc); 1349 object_unref(OBJECT(client->sioc)); 1350 object_unref(OBJECT(client->ioc)); 1351 if (client->tlscreds) { 1352 object_unref(OBJECT(client->tlscreds)); 1353 } 1354 g_free(client->tlsauthz); 1355 if (client->exp) { 1356 QTAILQ_REMOVE(&client->exp->clients, client, next); 1357 nbd_export_put(client->exp); 1358 } 1359 g_free(client); 1360 } 1361 } 1362 1363 static void client_close(NBDClient *client, bool negotiated) 1364 { 1365 if (client->closing) { 1366 return; 1367 } 1368 1369 client->closing = true; 1370 1371 /* Force requests to finish. They will drop their own references, 1372 * then we'll close the socket and free the NBDClient. 1373 */ 1374 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1375 NULL); 1376 1377 /* Also tell the client, so that they release their reference. */ 1378 if (client->close_fn) { 1379 client->close_fn(client, negotiated); 1380 } 1381 } 1382 1383 static NBDRequestData *nbd_request_get(NBDClient *client) 1384 { 1385 NBDRequestData *req; 1386 1387 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1388 client->nb_requests++; 1389 1390 req = g_new0(NBDRequestData, 1); 1391 nbd_client_get(client); 1392 req->client = client; 1393 return req; 1394 } 1395 1396 static void nbd_request_put(NBDRequestData *req) 1397 { 1398 NBDClient *client = req->client; 1399 1400 if (req->data) { 1401 qemu_vfree(req->data); 1402 } 1403 g_free(req); 1404 1405 client->nb_requests--; 1406 nbd_client_receive_next_request(client); 1407 1408 nbd_client_put(client); 1409 } 1410 1411 static void blk_aio_attached(AioContext *ctx, void *opaque) 1412 { 1413 NBDExport *exp = opaque; 1414 NBDClient *client; 1415 1416 trace_nbd_blk_aio_attached(exp->name, ctx); 1417 1418 exp->ctx = ctx; 1419 1420 QTAILQ_FOREACH(client, &exp->clients, next) { 1421 qio_channel_attach_aio_context(client->ioc, ctx); 1422 if (client->recv_coroutine) { 1423 aio_co_schedule(ctx, client->recv_coroutine); 1424 } 1425 if (client->send_coroutine) { 1426 aio_co_schedule(ctx, client->send_coroutine); 1427 } 1428 } 1429 } 1430 1431 static void blk_aio_detach(void *opaque) 1432 { 1433 NBDExport *exp = opaque; 1434 NBDClient *client; 1435 1436 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1437 1438 QTAILQ_FOREACH(client, &exp->clients, next) { 1439 qio_channel_detach_aio_context(client->ioc); 1440 } 1441 1442 exp->ctx = NULL; 1443 } 1444 1445 static void nbd_eject_notifier(Notifier *n, void *data) 1446 { 1447 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1448 nbd_export_close(exp); 1449 } 1450 1451 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, 1452 uint64_t size, const char *name, const char *desc, 1453 const char *bitmap, uint16_t nbdflags, 1454 void (*close)(NBDExport *), bool writethrough, 1455 BlockBackend *on_eject_blk, Error **errp) 1456 { 1457 AioContext *ctx; 1458 BlockBackend *blk; 1459 NBDExport *exp = g_new0(NBDExport, 1); 1460 uint64_t perm; 1461 int ret; 1462 1463 /* 1464 * NBD exports are used for non-shared storage migration. Make sure 1465 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1466 * access since the export could be available before migration handover. 1467 */ 1468 assert(name); 1469 ctx = bdrv_get_aio_context(bs); 1470 aio_context_acquire(ctx); 1471 bdrv_invalidate_cache(bs, NULL); 1472 aio_context_release(ctx); 1473 1474 /* Don't allow resize while the NBD server is running, otherwise we don't 1475 * care what happens with the node. */ 1476 perm = BLK_PERM_CONSISTENT_READ; 1477 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { 1478 perm |= BLK_PERM_WRITE; 1479 } 1480 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1481 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1482 ret = blk_insert_bs(blk, bs, errp); 1483 if (ret < 0) { 1484 goto fail; 1485 } 1486 blk_set_enable_write_cache(blk, !writethrough); 1487 1488 exp->refcount = 1; 1489 QTAILQ_INIT(&exp->clients); 1490 exp->blk = blk; 1491 assert(dev_offset <= INT64_MAX); 1492 exp->dev_offset = dev_offset; 1493 exp->name = g_strdup(name); 1494 exp->description = g_strdup(desc); 1495 exp->nbdflags = nbdflags; 1496 assert(size <= INT64_MAX - dev_offset); 1497 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1498 1499 if (bitmap) { 1500 BdrvDirtyBitmap *bm = NULL; 1501 1502 while (true) { 1503 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1504 if (bm != NULL || bs->backing == NULL) { 1505 break; 1506 } 1507 1508 bs = bs->backing->bs; 1509 } 1510 1511 if (bm == NULL) { 1512 error_setg(errp, "Bitmap '%s' is not found", bitmap); 1513 goto fail; 1514 } 1515 1516 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1517 goto fail; 1518 } 1519 1520 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) && 1521 bdrv_dirty_bitmap_enabled(bm)) { 1522 error_setg(errp, 1523 "Enabled bitmap '%s' incompatible with readonly export", 1524 bitmap); 1525 goto fail; 1526 } 1527 1528 bdrv_dirty_bitmap_set_busy(bm, true); 1529 exp->export_bitmap = bm; 1530 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1531 bitmap); 1532 } 1533 1534 exp->close = close; 1535 exp->ctx = blk_get_aio_context(blk); 1536 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1537 1538 if (on_eject_blk) { 1539 blk_ref(on_eject_blk); 1540 exp->eject_notifier_blk = on_eject_blk; 1541 exp->eject_notifier.notify = nbd_eject_notifier; 1542 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1543 } 1544 QTAILQ_INSERT_TAIL(&exports, exp, next); 1545 nbd_export_get(exp); 1546 return exp; 1547 1548 fail: 1549 blk_unref(blk); 1550 g_free(exp->name); 1551 g_free(exp->description); 1552 g_free(exp); 1553 return NULL; 1554 } 1555 1556 NBDExport *nbd_export_find(const char *name) 1557 { 1558 NBDExport *exp; 1559 QTAILQ_FOREACH(exp, &exports, next) { 1560 if (strcmp(name, exp->name) == 0) { 1561 return exp; 1562 } 1563 } 1564 1565 return NULL; 1566 } 1567 1568 void nbd_export_close(NBDExport *exp) 1569 { 1570 NBDClient *client, *next; 1571 1572 nbd_export_get(exp); 1573 /* 1574 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1575 * close mode that stops advertising the export to new clients but 1576 * still permits existing clients to run to completion? Because of 1577 * that possibility, nbd_export_close() can be called more than 1578 * once on an export. 1579 */ 1580 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1581 client_close(client, true); 1582 } 1583 if (exp->name) { 1584 nbd_export_put(exp); 1585 g_free(exp->name); 1586 exp->name = NULL; 1587 QTAILQ_REMOVE(&exports, exp, next); 1588 } 1589 g_free(exp->description); 1590 exp->description = NULL; 1591 nbd_export_put(exp); 1592 } 1593 1594 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1595 { 1596 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1597 nbd_export_close(exp); 1598 return; 1599 } 1600 1601 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1602 1603 error_setg(errp, "export '%s' still in use", exp->name); 1604 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1605 } 1606 1607 void nbd_export_get(NBDExport *exp) 1608 { 1609 assert(exp->refcount > 0); 1610 exp->refcount++; 1611 } 1612 1613 void nbd_export_put(NBDExport *exp) 1614 { 1615 assert(exp->refcount > 0); 1616 if (exp->refcount == 1) { 1617 nbd_export_close(exp); 1618 } 1619 1620 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1621 * if someone calls nbd_export_put() on named export not through 1622 * nbd_export_set_name() when refcount is 1. So, let's assert that 1623 * it is > 0. 1624 */ 1625 assert(exp->refcount > 0); 1626 if (--exp->refcount == 0) { 1627 assert(exp->name == NULL); 1628 assert(exp->description == NULL); 1629 1630 if (exp->close) { 1631 exp->close(exp); 1632 } 1633 1634 if (exp->blk) { 1635 if (exp->eject_notifier_blk) { 1636 notifier_remove(&exp->eject_notifier); 1637 blk_unref(exp->eject_notifier_blk); 1638 } 1639 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1640 blk_aio_detach, exp); 1641 blk_unref(exp->blk); 1642 exp->blk = NULL; 1643 } 1644 1645 if (exp->export_bitmap) { 1646 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); 1647 g_free(exp->export_bitmap_context); 1648 } 1649 1650 g_free(exp); 1651 } 1652 } 1653 1654 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1655 { 1656 return exp->blk; 1657 } 1658 1659 void nbd_export_close_all(void) 1660 { 1661 NBDExport *exp, *next; 1662 1663 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1664 nbd_export_close(exp); 1665 } 1666 } 1667 1668 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1669 unsigned niov, Error **errp) 1670 { 1671 int ret; 1672 1673 g_assert(qemu_in_coroutine()); 1674 qemu_co_mutex_lock(&client->send_lock); 1675 client->send_coroutine = qemu_coroutine_self(); 1676 1677 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1678 1679 client->send_coroutine = NULL; 1680 qemu_co_mutex_unlock(&client->send_lock); 1681 1682 return ret; 1683 } 1684 1685 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1686 uint64_t handle) 1687 { 1688 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1689 stl_be_p(&reply->error, error); 1690 stq_be_p(&reply->handle, handle); 1691 } 1692 1693 static int nbd_co_send_simple_reply(NBDClient *client, 1694 uint64_t handle, 1695 uint32_t error, 1696 void *data, 1697 size_t len, 1698 Error **errp) 1699 { 1700 NBDSimpleReply reply; 1701 int nbd_err = system_errno_to_nbd_errno(error); 1702 struct iovec iov[] = { 1703 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1704 {.iov_base = data, .iov_len = len} 1705 }; 1706 1707 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1708 len); 1709 set_be_simple_reply(&reply, nbd_err, handle); 1710 1711 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1712 } 1713 1714 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1715 uint16_t type, uint64_t handle, uint32_t length) 1716 { 1717 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1718 stw_be_p(&chunk->flags, flags); 1719 stw_be_p(&chunk->type, type); 1720 stq_be_p(&chunk->handle, handle); 1721 stl_be_p(&chunk->length, length); 1722 } 1723 1724 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1725 uint64_t handle, 1726 Error **errp) 1727 { 1728 NBDStructuredReplyChunk chunk; 1729 struct iovec iov[] = { 1730 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1731 }; 1732 1733 trace_nbd_co_send_structured_done(handle); 1734 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1735 1736 return nbd_co_send_iov(client, iov, 1, errp); 1737 } 1738 1739 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1740 uint64_t handle, 1741 uint64_t offset, 1742 void *data, 1743 size_t size, 1744 bool final, 1745 Error **errp) 1746 { 1747 NBDStructuredReadData chunk; 1748 struct iovec iov[] = { 1749 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1750 {.iov_base = data, .iov_len = size} 1751 }; 1752 1753 assert(size); 1754 trace_nbd_co_send_structured_read(handle, offset, data, size); 1755 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1756 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1757 sizeof(chunk) - sizeof(chunk.h) + size); 1758 stq_be_p(&chunk.offset, offset); 1759 1760 return nbd_co_send_iov(client, iov, 2, errp); 1761 } 1762 1763 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1764 uint64_t handle, 1765 uint32_t error, 1766 const char *msg, 1767 Error **errp) 1768 { 1769 NBDStructuredError chunk; 1770 int nbd_err = system_errno_to_nbd_errno(error); 1771 struct iovec iov[] = { 1772 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1773 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1774 }; 1775 1776 assert(nbd_err); 1777 trace_nbd_co_send_structured_error(handle, nbd_err, 1778 nbd_err_lookup(nbd_err), msg ? msg : ""); 1779 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1780 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1781 stl_be_p(&chunk.error, nbd_err); 1782 stw_be_p(&chunk.message_length, iov[1].iov_len); 1783 1784 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1785 } 1786 1787 /* Do a sparse read and send the structured reply to the client. 1788 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1789 * reported to the client, at which point this function succeeds. 1790 */ 1791 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1792 uint64_t handle, 1793 uint64_t offset, 1794 uint8_t *data, 1795 size_t size, 1796 Error **errp) 1797 { 1798 int ret = 0; 1799 NBDExport *exp = client->exp; 1800 size_t progress = 0; 1801 1802 while (progress < size) { 1803 int64_t pnum; 1804 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1805 offset + progress, 1806 size - progress, &pnum, NULL, 1807 NULL); 1808 bool final; 1809 1810 if (status < 0) { 1811 char *msg = g_strdup_printf("unable to check for holes: %s", 1812 strerror(-status)); 1813 1814 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1815 errp); 1816 g_free(msg); 1817 return ret; 1818 } 1819 assert(pnum && pnum <= size - progress); 1820 final = progress + pnum == size; 1821 if (status & BDRV_BLOCK_ZERO) { 1822 NBDStructuredReadHole chunk; 1823 struct iovec iov[] = { 1824 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1825 }; 1826 1827 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1828 pnum); 1829 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1830 NBD_REPLY_TYPE_OFFSET_HOLE, 1831 handle, sizeof(chunk) - sizeof(chunk.h)); 1832 stq_be_p(&chunk.offset, offset + progress); 1833 stl_be_p(&chunk.length, pnum); 1834 ret = nbd_co_send_iov(client, iov, 1, errp); 1835 } else { 1836 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1837 data + progress, pnum); 1838 if (ret < 0) { 1839 error_setg_errno(errp, -ret, "reading from file failed"); 1840 break; 1841 } 1842 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1843 data + progress, pnum, final, 1844 errp); 1845 } 1846 1847 if (ret < 0) { 1848 break; 1849 } 1850 progress += pnum; 1851 } 1852 return ret; 1853 } 1854 1855 /* 1856 * Populate @extents from block status. Update @bytes to be the actual 1857 * length encoded (which may be smaller than the original), and update 1858 * @nb_extents to the number of extents used. 1859 * 1860 * Returns zero on success and -errno on bdrv_block_status_above failure. 1861 */ 1862 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1863 uint64_t *bytes, NBDExtent *extents, 1864 unsigned int *nb_extents) 1865 { 1866 uint64_t remaining_bytes = *bytes; 1867 NBDExtent *extent = extents, *extents_end = extents + *nb_extents; 1868 bool first_extent = true; 1869 1870 assert(*nb_extents); 1871 while (remaining_bytes) { 1872 uint32_t flags; 1873 int64_t num; 1874 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, 1875 &num, NULL, NULL); 1876 1877 if (ret < 0) { 1878 return ret; 1879 } 1880 1881 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1882 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1883 offset += num; 1884 remaining_bytes -= num; 1885 1886 if (first_extent) { 1887 extent->flags = flags; 1888 extent->length = num; 1889 first_extent = false; 1890 continue; 1891 } 1892 1893 if (flags == extent->flags) { 1894 /* extend current extent */ 1895 extent->length += num; 1896 } else { 1897 if (extent + 1 == extents_end) { 1898 break; 1899 } 1900 1901 /* start new extent */ 1902 extent++; 1903 extent->flags = flags; 1904 extent->length = num; 1905 } 1906 } 1907 1908 extents_end = extent + 1; 1909 1910 for (extent = extents; extent < extents_end; extent++) { 1911 extent->flags = cpu_to_be32(extent->flags); 1912 extent->length = cpu_to_be32(extent->length); 1913 } 1914 1915 *bytes -= remaining_bytes; 1916 *nb_extents = extents_end - extents; 1917 1918 return 0; 1919 } 1920 1921 /* nbd_co_send_extents 1922 * 1923 * @length is only for tracing purposes (and may be smaller or larger 1924 * than the client's original request). @last controls whether 1925 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in 1926 * big-endian format. 1927 */ 1928 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1929 NBDExtent *extents, unsigned int nb_extents, 1930 uint64_t length, bool last, 1931 uint32_t context_id, Error **errp) 1932 { 1933 NBDStructuredMeta chunk; 1934 1935 struct iovec iov[] = { 1936 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1937 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} 1938 }; 1939 1940 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); 1941 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1942 NBD_REPLY_TYPE_BLOCK_STATUS, 1943 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1944 stl_be_p(&chunk.context_id, context_id); 1945 1946 return nbd_co_send_iov(client, iov, 2, errp); 1947 } 1948 1949 /* Get block status from the exported device and send it to the client */ 1950 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1951 BlockDriverState *bs, uint64_t offset, 1952 uint32_t length, bool dont_fragment, 1953 bool last, uint32_t context_id, 1954 Error **errp) 1955 { 1956 int ret; 1957 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 1958 NBDExtent *extents = g_new(NBDExtent, nb_extents); 1959 uint64_t final_length = length; 1960 1961 ret = blockstatus_to_extents(bs, offset, &final_length, extents, 1962 &nb_extents); 1963 if (ret < 0) { 1964 g_free(extents); 1965 return nbd_co_send_structured_error( 1966 client, handle, -ret, "can't get block status", errp); 1967 } 1968 1969 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 1970 final_length, last, context_id, errp); 1971 1972 g_free(extents); 1973 1974 return ret; 1975 } 1976 1977 /* 1978 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the 1979 * final extent may exceed the original @length. Store in @length the 1980 * byte length encoded (which may be smaller or larger than the 1981 * original), and return the number of extents used. 1982 */ 1983 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, 1984 uint64_t *length, NBDExtent *extents, 1985 unsigned int nb_extents, 1986 bool dont_fragment) 1987 { 1988 uint64_t begin = offset, end = offset; 1989 uint64_t overall_end = offset + *length; 1990 unsigned int i = 0; 1991 BdrvDirtyBitmapIter *it; 1992 bool dirty; 1993 1994 bdrv_dirty_bitmap_lock(bitmap); 1995 1996 it = bdrv_dirty_iter_new(bitmap); 1997 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset); 1998 1999 assert(begin < overall_end && nb_extents); 2000 while (begin < overall_end && i < nb_extents) { 2001 bool next_dirty = !dirty; 2002 2003 if (dirty) { 2004 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX); 2005 } else { 2006 bdrv_set_dirty_iter(it, begin); 2007 end = bdrv_dirty_iter_next(it); 2008 } 2009 if (end == -1 || end - begin > UINT32_MAX) { 2010 /* Cap to an aligned value < 4G beyond begin. */ 2011 end = MIN(bdrv_dirty_bitmap_size(bitmap), 2012 begin + UINT32_MAX + 1 - 2013 bdrv_dirty_bitmap_granularity(bitmap)); 2014 next_dirty = dirty; 2015 } 2016 if (dont_fragment && end > overall_end) { 2017 end = overall_end; 2018 } 2019 2020 extents[i].length = cpu_to_be32(end - begin); 2021 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); 2022 i++; 2023 begin = end; 2024 dirty = next_dirty; 2025 } 2026 2027 bdrv_dirty_iter_free(it); 2028 2029 bdrv_dirty_bitmap_unlock(bitmap); 2030 2031 assert(offset < end); 2032 *length = end - offset; 2033 return i; 2034 } 2035 2036 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2037 BdrvDirtyBitmap *bitmap, uint64_t offset, 2038 uint32_t length, bool dont_fragment, bool last, 2039 uint32_t context_id, Error **errp) 2040 { 2041 int ret; 2042 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; 2043 NBDExtent *extents = g_new(NBDExtent, nb_extents); 2044 uint64_t final_length = length; 2045 2046 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, 2047 nb_extents, dont_fragment); 2048 2049 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2050 final_length, last, context_id, errp); 2051 2052 g_free(extents); 2053 2054 return ret; 2055 } 2056 2057 /* nbd_co_receive_request 2058 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2059 * connection right away, and any other negative value to report an error to 2060 * the client (although the caller may still need to disconnect after reporting 2061 * the error). 2062 */ 2063 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2064 Error **errp) 2065 { 2066 NBDClient *client = req->client; 2067 int valid_flags; 2068 2069 g_assert(qemu_in_coroutine()); 2070 assert(client->recv_coroutine == qemu_coroutine_self()); 2071 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2072 return -EIO; 2073 } 2074 2075 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2076 nbd_cmd_lookup(request->type)); 2077 2078 if (request->type != NBD_CMD_WRITE) { 2079 /* No payload, we are ready to read the next request. */ 2080 req->complete = true; 2081 } 2082 2083 if (request->type == NBD_CMD_DISC) { 2084 /* Special case: we're going to disconnect without a reply, 2085 * whether or not flags, from, or len are bogus */ 2086 return -EIO; 2087 } 2088 2089 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2090 request->type == NBD_CMD_CACHE) 2091 { 2092 if (request->len > NBD_MAX_BUFFER_SIZE) { 2093 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2094 request->len, NBD_MAX_BUFFER_SIZE); 2095 return -EINVAL; 2096 } 2097 2098 req->data = blk_try_blockalign(client->exp->blk, request->len); 2099 if (req->data == NULL) { 2100 error_setg(errp, "No memory"); 2101 return -ENOMEM; 2102 } 2103 } 2104 if (request->type == NBD_CMD_WRITE) { 2105 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2106 errp) < 0) 2107 { 2108 return -EIO; 2109 } 2110 req->complete = true; 2111 2112 trace_nbd_co_receive_request_payload_received(request->handle, 2113 request->len); 2114 } 2115 2116 /* Sanity checks. */ 2117 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2118 (request->type == NBD_CMD_WRITE || 2119 request->type == NBD_CMD_WRITE_ZEROES || 2120 request->type == NBD_CMD_TRIM)) { 2121 error_setg(errp, "Export is read-only"); 2122 return -EROFS; 2123 } 2124 if (request->from > client->exp->size || 2125 request->len > client->exp->size - request->from) { 2126 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2127 ", Size: %" PRIu64, request->from, request->len, 2128 client->exp->size); 2129 return (request->type == NBD_CMD_WRITE || 2130 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2131 } 2132 valid_flags = NBD_CMD_FLAG_FUA; 2133 if (request->type == NBD_CMD_READ && client->structured_reply) { 2134 valid_flags |= NBD_CMD_FLAG_DF; 2135 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2136 valid_flags |= NBD_CMD_FLAG_NO_HOLE; 2137 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2138 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2139 } 2140 if (request->flags & ~valid_flags) { 2141 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2142 nbd_cmd_lookup(request->type), request->flags); 2143 return -EINVAL; 2144 } 2145 2146 return 0; 2147 } 2148 2149 /* Send simple reply without a payload, or a structured error 2150 * @error_msg is ignored if @ret >= 0 2151 * Returns 0 if connection is still live, -errno on failure to talk to client 2152 */ 2153 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2154 uint64_t handle, 2155 int ret, 2156 const char *error_msg, 2157 Error **errp) 2158 { 2159 if (client->structured_reply && ret < 0) { 2160 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2161 errp); 2162 } else { 2163 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2164 NULL, 0, errp); 2165 } 2166 } 2167 2168 /* Handle NBD_CMD_READ request. 2169 * Return -errno if sending fails. Other errors are reported directly to the 2170 * client as an error reply. */ 2171 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2172 uint8_t *data, Error **errp) 2173 { 2174 int ret; 2175 NBDExport *exp = client->exp; 2176 2177 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE); 2178 2179 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2180 if (request->flags & NBD_CMD_FLAG_FUA) { 2181 ret = blk_co_flush(exp->blk); 2182 if (ret < 0) { 2183 return nbd_send_generic_reply(client, request->handle, ret, 2184 "flush failed", errp); 2185 } 2186 } 2187 2188 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2189 request->len && request->type != NBD_CMD_CACHE) 2190 { 2191 return nbd_co_send_sparse_read(client, request->handle, request->from, 2192 data, request->len, errp); 2193 } 2194 2195 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, 2196 request->len); 2197 if (ret < 0 || request->type == NBD_CMD_CACHE) { 2198 return nbd_send_generic_reply(client, request->handle, ret, 2199 "reading from file failed", errp); 2200 } 2201 2202 if (client->structured_reply) { 2203 if (request->len) { 2204 return nbd_co_send_structured_read(client, request->handle, 2205 request->from, data, 2206 request->len, true, errp); 2207 } else { 2208 return nbd_co_send_structured_done(client, request->handle, errp); 2209 } 2210 } else { 2211 return nbd_co_send_simple_reply(client, request->handle, 0, 2212 data, request->len, errp); 2213 } 2214 } 2215 2216 /* Handle NBD request. 2217 * Return -errno if sending fails. Other errors are reported directly to the 2218 * client as an error reply. */ 2219 static coroutine_fn int nbd_handle_request(NBDClient *client, 2220 NBDRequest *request, 2221 uint8_t *data, Error **errp) 2222 { 2223 int ret; 2224 int flags; 2225 NBDExport *exp = client->exp; 2226 char *msg; 2227 2228 switch (request->type) { 2229 case NBD_CMD_READ: 2230 case NBD_CMD_CACHE: 2231 return nbd_do_cmd_read(client, request, data, errp); 2232 2233 case NBD_CMD_WRITE: 2234 flags = 0; 2235 if (request->flags & NBD_CMD_FLAG_FUA) { 2236 flags |= BDRV_REQ_FUA; 2237 } 2238 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, 2239 data, request->len, flags); 2240 return nbd_send_generic_reply(client, request->handle, ret, 2241 "writing to file failed", errp); 2242 2243 case NBD_CMD_WRITE_ZEROES: 2244 flags = 0; 2245 if (request->flags & NBD_CMD_FLAG_FUA) { 2246 flags |= BDRV_REQ_FUA; 2247 } 2248 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2249 flags |= BDRV_REQ_MAY_UNMAP; 2250 } 2251 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, 2252 request->len, flags); 2253 return nbd_send_generic_reply(client, request->handle, ret, 2254 "writing to file failed", errp); 2255 2256 case NBD_CMD_DISC: 2257 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2258 abort(); 2259 2260 case NBD_CMD_FLUSH: 2261 ret = blk_co_flush(exp->blk); 2262 return nbd_send_generic_reply(client, request->handle, ret, 2263 "flush failed", errp); 2264 2265 case NBD_CMD_TRIM: 2266 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, 2267 request->len); 2268 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { 2269 ret = blk_co_flush(exp->blk); 2270 } 2271 return nbd_send_generic_reply(client, request->handle, ret, 2272 "discard failed", errp); 2273 2274 case NBD_CMD_BLOCK_STATUS: 2275 if (!request->len) { 2276 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2277 "need non-zero length", errp); 2278 } 2279 if (client->export_meta.valid && 2280 (client->export_meta.base_allocation || 2281 client->export_meta.bitmap)) 2282 { 2283 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2284 2285 if (client->export_meta.base_allocation) { 2286 ret = nbd_co_send_block_status(client, request->handle, 2287 blk_bs(exp->blk), request->from, 2288 request->len, dont_fragment, 2289 !client->export_meta.bitmap, 2290 NBD_META_ID_BASE_ALLOCATION, 2291 errp); 2292 if (ret < 0) { 2293 return ret; 2294 } 2295 } 2296 2297 if (client->export_meta.bitmap) { 2298 ret = nbd_co_send_bitmap(client, request->handle, 2299 client->exp->export_bitmap, 2300 request->from, request->len, 2301 dont_fragment, 2302 true, NBD_META_ID_DIRTY_BITMAP, errp); 2303 if (ret < 0) { 2304 return ret; 2305 } 2306 } 2307 2308 return ret; 2309 } else { 2310 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2311 "CMD_BLOCK_STATUS not negotiated", 2312 errp); 2313 } 2314 2315 default: 2316 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2317 request->type); 2318 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2319 errp); 2320 g_free(msg); 2321 return ret; 2322 } 2323 } 2324 2325 /* Owns a reference to the NBDClient passed as opaque. */ 2326 static coroutine_fn void nbd_trip(void *opaque) 2327 { 2328 NBDClient *client = opaque; 2329 NBDRequestData *req; 2330 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2331 int ret; 2332 Error *local_err = NULL; 2333 2334 trace_nbd_trip(); 2335 if (client->closing) { 2336 nbd_client_put(client); 2337 return; 2338 } 2339 2340 req = nbd_request_get(client); 2341 ret = nbd_co_receive_request(req, &request, &local_err); 2342 client->recv_coroutine = NULL; 2343 2344 if (client->closing) { 2345 /* 2346 * The client may be closed when we are blocked in 2347 * nbd_co_receive_request() 2348 */ 2349 goto done; 2350 } 2351 2352 nbd_client_receive_next_request(client); 2353 if (ret == -EIO) { 2354 goto disconnect; 2355 } 2356 2357 if (ret < 0) { 2358 /* It wans't -EIO, so, according to nbd_co_receive_request() 2359 * semantics, we should return the error to the client. */ 2360 Error *export_err = local_err; 2361 2362 local_err = NULL; 2363 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2364 error_get_pretty(export_err), &local_err); 2365 error_free(export_err); 2366 } else { 2367 ret = nbd_handle_request(client, &request, req->data, &local_err); 2368 } 2369 if (ret < 0) { 2370 error_prepend(&local_err, "Failed to send reply: "); 2371 goto disconnect; 2372 } 2373 2374 /* We must disconnect after NBD_CMD_WRITE if we did not 2375 * read the payload. 2376 */ 2377 if (!req->complete) { 2378 error_setg(&local_err, "Request handling failed in intermediate state"); 2379 goto disconnect; 2380 } 2381 2382 done: 2383 nbd_request_put(req); 2384 nbd_client_put(client); 2385 return; 2386 2387 disconnect: 2388 if (local_err) { 2389 error_reportf_err(local_err, "Disconnect client, due to: "); 2390 } 2391 nbd_request_put(req); 2392 client_close(client, true); 2393 nbd_client_put(client); 2394 } 2395 2396 static void nbd_client_receive_next_request(NBDClient *client) 2397 { 2398 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2399 nbd_client_get(client); 2400 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2401 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 2402 } 2403 } 2404 2405 static coroutine_fn void nbd_co_client_start(void *opaque) 2406 { 2407 NBDClient *client = opaque; 2408 Error *local_err = NULL; 2409 2410 qemu_co_mutex_init(&client->send_lock); 2411 2412 if (nbd_negotiate(client, &local_err)) { 2413 if (local_err) { 2414 error_report_err(local_err); 2415 } 2416 client_close(client, false); 2417 return; 2418 } 2419 2420 nbd_client_receive_next_request(client); 2421 } 2422 2423 /* 2424 * Create a new client listener using the given channel @sioc. 2425 * Begin servicing it in a coroutine. When the connection closes, call 2426 * @close_fn with an indication of whether the client completed negotiation. 2427 */ 2428 void nbd_client_new(QIOChannelSocket *sioc, 2429 QCryptoTLSCreds *tlscreds, 2430 const char *tlsauthz, 2431 void (*close_fn)(NBDClient *, bool)) 2432 { 2433 NBDClient *client; 2434 Coroutine *co; 2435 2436 client = g_new0(NBDClient, 1); 2437 client->refcount = 1; 2438 client->tlscreds = tlscreds; 2439 if (tlscreds) { 2440 object_ref(OBJECT(client->tlscreds)); 2441 } 2442 client->tlsauthz = g_strdup(tlsauthz); 2443 client->sioc = sioc; 2444 object_ref(OBJECT(client->sioc)); 2445 client->ioc = QIO_CHANNEL(sioc); 2446 object_ref(OBJECT(client->ioc)); 2447 client->close_fn = close_fn; 2448 2449 co = qemu_coroutine_create(nbd_co_client_start, client); 2450 qemu_coroutine_enter(co); 2451 } 2452