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 "qemu/queue.h" 23 #include "trace.h" 24 #include "nbd-internal.h" 25 #include "qemu/units.h" 26 27 #define NBD_META_ID_BASE_ALLOCATION 0 28 #define NBD_META_ID_DIRTY_BITMAP 1 29 30 /* 31 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical 32 * constant. If an increase is needed, note that the NBD protocol 33 * recommends no larger than 32 mb, so that the client won't consider 34 * the reply as a denial of service attack. 35 */ 36 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) 37 38 static int system_errno_to_nbd_errno(int err) 39 { 40 switch (err) { 41 case 0: 42 return NBD_SUCCESS; 43 case EPERM: 44 case EROFS: 45 return NBD_EPERM; 46 case EIO: 47 return NBD_EIO; 48 case ENOMEM: 49 return NBD_ENOMEM; 50 #ifdef EDQUOT 51 case EDQUOT: 52 #endif 53 case EFBIG: 54 case ENOSPC: 55 return NBD_ENOSPC; 56 case EOVERFLOW: 57 return NBD_EOVERFLOW; 58 case ENOTSUP: 59 #if ENOTSUP != EOPNOTSUPP 60 case EOPNOTSUPP: 61 #endif 62 return NBD_ENOTSUP; 63 case ESHUTDOWN: 64 return NBD_ESHUTDOWN; 65 case EINVAL: 66 default: 67 return NBD_EINVAL; 68 } 69 } 70 71 /* Definitions for opaque data types */ 72 73 typedef struct NBDRequestData NBDRequestData; 74 75 struct NBDRequestData { 76 QSIMPLEQ_ENTRY(NBDRequestData) entry; 77 NBDClient *client; 78 uint8_t *data; 79 bool complete; 80 }; 81 82 struct NBDExport { 83 int refcount; 84 void (*close)(NBDExport *exp); 85 86 BlockBackend *blk; 87 char *name; 88 char *description; 89 uint64_t dev_offset; 90 uint64_t size; 91 uint16_t nbdflags; 92 QTAILQ_HEAD(, NBDClient) clients; 93 QTAILQ_ENTRY(NBDExport) next; 94 95 AioContext *ctx; 96 97 BlockBackend *eject_notifier_blk; 98 Notifier eject_notifier; 99 100 BdrvDirtyBitmap *export_bitmap; 101 char *export_bitmap_context; 102 }; 103 104 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 105 106 /* NBDExportMetaContexts represents a list of contexts to be exported, 107 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 108 * NBD_OPT_LIST_META_CONTEXT. */ 109 typedef struct NBDExportMetaContexts { 110 NBDExport *exp; 111 bool valid; /* means that negotiation of the option finished without 112 errors */ 113 bool base_allocation; /* export base:allocation context (block status) */ 114 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */ 115 } NBDExportMetaContexts; 116 117 struct NBDClient { 118 int refcount; 119 void (*close_fn)(NBDClient *client, bool negotiated); 120 121 NBDExport *exp; 122 QCryptoTLSCreds *tlscreds; 123 char *tlsauthz; 124 QIOChannelSocket *sioc; /* The underlying data channel */ 125 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 126 127 Coroutine *recv_coroutine; 128 129 CoMutex send_lock; 130 Coroutine *send_coroutine; 131 132 QTAILQ_ENTRY(NBDClient) next; 133 int nb_requests; 134 bool closing; 135 136 uint32_t check_align; /* If non-zero, check for aligned client requests */ 137 138 bool structured_reply; 139 NBDExportMetaContexts export_meta; 140 141 uint32_t opt; /* Current option being negotiated */ 142 uint32_t optlen; /* remaining length of data in ioc for the option being 143 negotiated now */ 144 }; 145 146 static void nbd_client_receive_next_request(NBDClient *client); 147 148 /* Basic flow for negotiation 149 150 Server Client 151 Negotiate 152 153 or 154 155 Server Client 156 Negotiate #1 157 Option 158 Negotiate #2 159 160 ---- 161 162 followed by 163 164 Server Client 165 Request 166 Response 167 Request 168 Response 169 ... 170 ... 171 Request (type == 2) 172 173 */ 174 175 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 176 uint32_t type, uint32_t length) 177 { 178 stq_be_p(&rep->magic, NBD_REP_MAGIC); 179 stl_be_p(&rep->option, option); 180 stl_be_p(&rep->type, type); 181 stl_be_p(&rep->length, length); 182 } 183 184 /* Send a reply header, including length, but no payload. 185 * Return -errno on error, 0 on success. */ 186 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 187 uint32_t len, Error **errp) 188 { 189 NBDOptionReply rep; 190 191 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 192 type, nbd_rep_lookup(type), len); 193 194 assert(len < NBD_MAX_BUFFER_SIZE); 195 196 set_be_option_rep(&rep, client->opt, type, len); 197 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 198 } 199 200 /* Send a reply header with default 0 length. 201 * Return -errno on error, 0 on success. */ 202 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 203 Error **errp) 204 { 205 return nbd_negotiate_send_rep_len(client, type, 0, errp); 206 } 207 208 /* Send an error reply. 209 * Return -errno on error, 0 on success. */ 210 static int GCC_FMT_ATTR(4, 0) 211 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 212 Error **errp, const char *fmt, va_list va) 213 { 214 g_autofree char *msg = NULL; 215 int ret; 216 size_t len; 217 218 msg = g_strdup_vprintf(fmt, va); 219 len = strlen(msg); 220 assert(len < 4096); 221 trace_nbd_negotiate_send_rep_err(msg); 222 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 223 if (ret < 0) { 224 return ret; 225 } 226 if (nbd_write(client->ioc, msg, len, errp) < 0) { 227 error_prepend(errp, "write failed (error message): "); 228 return -EIO; 229 } 230 231 return 0; 232 } 233 234 /* Send an error reply. 235 * Return -errno on error, 0 on success. */ 236 static int GCC_FMT_ATTR(4, 5) 237 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 238 Error **errp, const char *fmt, ...) 239 { 240 va_list va; 241 int ret; 242 243 va_start(va, fmt); 244 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 245 va_end(va); 246 return ret; 247 } 248 249 /* Drop remainder of the current option, and send a reply with the 250 * given error type and message. Return -errno on read or write 251 * failure; or 0 if connection is still live. */ 252 static int GCC_FMT_ATTR(4, 0) 253 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 254 const char *fmt, va_list va) 255 { 256 int ret = nbd_drop(client->ioc, client->optlen, errp); 257 258 client->optlen = 0; 259 if (!ret) { 260 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 261 } 262 return ret; 263 } 264 265 static int GCC_FMT_ATTR(4, 5) 266 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 267 const char *fmt, ...) 268 { 269 int ret; 270 va_list va; 271 272 va_start(va, fmt); 273 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 274 va_end(va); 275 276 return ret; 277 } 278 279 static int GCC_FMT_ATTR(3, 4) 280 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 281 { 282 int ret; 283 va_list va; 284 285 va_start(va, fmt); 286 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 287 va_end(va); 288 289 return ret; 290 } 291 292 /* Read size bytes from the unparsed payload of the current option. 293 * Return -errno on I/O error, 0 if option was completely handled by 294 * sending a reply about inconsistent lengths, or 1 on success. */ 295 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 296 Error **errp) 297 { 298 if (size > client->optlen) { 299 return nbd_opt_invalid(client, errp, 300 "Inconsistent lengths in option %s", 301 nbd_opt_lookup(client->opt)); 302 } 303 client->optlen -= size; 304 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1; 305 } 306 307 /* Drop size bytes from the unparsed payload of the current option. 308 * Return -errno on I/O error, 0 if option was completely handled by 309 * sending a reply about inconsistent lengths, or 1 on success. */ 310 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 311 { 312 if (size > client->optlen) { 313 return nbd_opt_invalid(client, errp, 314 "Inconsistent lengths in option %s", 315 nbd_opt_lookup(client->opt)); 316 } 317 client->optlen -= size; 318 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 319 } 320 321 /* nbd_opt_read_name 322 * 323 * Read a string with the format: 324 * uint32_t len (<= NBD_MAX_NAME_SIZE) 325 * len bytes string (not 0-terminated) 326 * 327 * @name should be enough to store NBD_MAX_NAME_SIZE+1. 328 * If @length is non-null, it will be set to the actual string length. 329 * 330 * Return -errno on I/O error, 0 if option was completely handled by 331 * sending a reply about inconsistent lengths, or 1 on success. 332 */ 333 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length, 334 Error **errp) 335 { 336 int ret; 337 uint32_t len; 338 339 ret = nbd_opt_read(client, &len, sizeof(len), errp); 340 if (ret <= 0) { 341 return ret; 342 } 343 len = cpu_to_be32(len); 344 345 if (len > NBD_MAX_NAME_SIZE) { 346 return nbd_opt_invalid(client, errp, 347 "Invalid name length: %" PRIu32, len); 348 } 349 350 ret = nbd_opt_read(client, name, len, errp); 351 if (ret <= 0) { 352 return ret; 353 } 354 name[len] = '\0'; 355 356 if (length) { 357 *length = len; 358 } 359 360 return 1; 361 } 362 363 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 364 * Return -errno on error, 0 on success. */ 365 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 366 Error **errp) 367 { 368 size_t name_len, desc_len; 369 uint32_t len; 370 const char *name = exp->name ? exp->name : ""; 371 const char *desc = exp->description ? exp->description : ""; 372 QIOChannel *ioc = client->ioc; 373 int ret; 374 375 trace_nbd_negotiate_send_rep_list(name, desc); 376 name_len = strlen(name); 377 desc_len = strlen(desc); 378 len = name_len + desc_len + sizeof(len); 379 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 380 if (ret < 0) { 381 return ret; 382 } 383 384 len = cpu_to_be32(name_len); 385 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 386 error_prepend(errp, "write failed (name length): "); 387 return -EINVAL; 388 } 389 390 if (nbd_write(ioc, name, name_len, errp) < 0) { 391 error_prepend(errp, "write failed (name buffer): "); 392 return -EINVAL; 393 } 394 395 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 396 error_prepend(errp, "write failed (description buffer): "); 397 return -EINVAL; 398 } 399 400 return 0; 401 } 402 403 /* Process the NBD_OPT_LIST command, with a potential series of replies. 404 * Return -errno on error, 0 on success. */ 405 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 406 { 407 NBDExport *exp; 408 assert(client->opt == NBD_OPT_LIST); 409 410 /* For each export, send a NBD_REP_SERVER reply. */ 411 QTAILQ_FOREACH(exp, &exports, next) { 412 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 413 return -EINVAL; 414 } 415 } 416 /* Finish with a NBD_REP_ACK. */ 417 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 418 } 419 420 static void nbd_check_meta_export(NBDClient *client) 421 { 422 client->export_meta.valid &= client->exp == client->export_meta.exp; 423 } 424 425 /* Send a reply to NBD_OPT_EXPORT_NAME. 426 * Return -errno on error, 0 on success. */ 427 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, 428 Error **errp) 429 { 430 char name[NBD_MAX_NAME_SIZE + 1]; 431 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 432 size_t len; 433 int ret; 434 uint16_t myflags; 435 436 /* Client sends: 437 [20 .. xx] export name (length bytes) 438 Server replies: 439 [ 0 .. 7] size 440 [ 8 .. 9] export flags 441 [10 .. 133] reserved (0) [unless no_zeroes] 442 */ 443 trace_nbd_negotiate_handle_export_name(); 444 if (client->optlen >= sizeof(name)) { 445 error_setg(errp, "Bad length received"); 446 return -EINVAL; 447 } 448 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 449 return -EIO; 450 } 451 name[client->optlen] = '\0'; 452 client->optlen = 0; 453 454 trace_nbd_negotiate_handle_export_name_request(name); 455 456 client->exp = nbd_export_find(name); 457 if (!client->exp) { 458 error_setg(errp, "export not found"); 459 return -EINVAL; 460 } 461 462 myflags = client->exp->nbdflags; 463 if (client->structured_reply) { 464 myflags |= NBD_FLAG_SEND_DF; 465 } 466 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags); 467 stq_be_p(buf, client->exp->size); 468 stw_be_p(buf + 8, myflags); 469 len = no_zeroes ? 10 : sizeof(buf); 470 ret = nbd_write(client->ioc, buf, len, errp); 471 if (ret < 0) { 472 error_prepend(errp, "write failed: "); 473 return ret; 474 } 475 476 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 477 nbd_export_get(client->exp); 478 nbd_check_meta_export(client); 479 480 return 0; 481 } 482 483 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 484 * The buffer does NOT include the info type prefix. 485 * Return -errno on error, 0 if ready to send more. */ 486 static int nbd_negotiate_send_info(NBDClient *client, 487 uint16_t info, uint32_t length, void *buf, 488 Error **errp) 489 { 490 int rc; 491 492 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 493 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 494 sizeof(info) + length, errp); 495 if (rc < 0) { 496 return rc; 497 } 498 info = cpu_to_be16(info); 499 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 500 return -EIO; 501 } 502 if (nbd_write(client->ioc, buf, length, errp) < 0) { 503 return -EIO; 504 } 505 return 0; 506 } 507 508 /* nbd_reject_length: Handle any unexpected payload. 509 * @fatal requests that we quit talking to the client, even if we are able 510 * to successfully send an error reply. 511 * Return: 512 * -errno transmission error occurred or @fatal was requested, errp is set 513 * 0 error message successfully sent to client, errp is not set 514 */ 515 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 516 { 517 int ret; 518 519 assert(client->optlen); 520 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 521 nbd_opt_lookup(client->opt)); 522 if (fatal && !ret) { 523 error_setg(errp, "option '%s' has unexpected length", 524 nbd_opt_lookup(client->opt)); 525 return -EINVAL; 526 } 527 return ret; 528 } 529 530 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 531 * Return -errno on error, 0 if ready for next option, and 1 to move 532 * into transmission phase. */ 533 static int nbd_negotiate_handle_info(NBDClient *client, Error **errp) 534 { 535 int rc; 536 char name[NBD_MAX_NAME_SIZE + 1]; 537 NBDExport *exp; 538 uint16_t requests; 539 uint16_t request; 540 uint32_t namelen; 541 bool sendname = false; 542 bool blocksize = false; 543 uint32_t sizes[3]; 544 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 545 uint32_t check_align = 0; 546 uint16_t myflags; 547 548 /* Client sends: 549 4 bytes: L, name length (can be 0) 550 L bytes: export name 551 2 bytes: N, number of requests (can be 0) 552 N * 2 bytes: N requests 553 */ 554 rc = nbd_opt_read_name(client, name, &namelen, errp); 555 if (rc <= 0) { 556 return rc; 557 } 558 trace_nbd_negotiate_handle_export_name_request(name); 559 560 rc = nbd_opt_read(client, &requests, sizeof(requests), errp); 561 if (rc <= 0) { 562 return rc; 563 } 564 requests = be16_to_cpu(requests); 565 trace_nbd_negotiate_handle_info_requests(requests); 566 while (requests--) { 567 rc = nbd_opt_read(client, &request, sizeof(request), errp); 568 if (rc <= 0) { 569 return rc; 570 } 571 request = be16_to_cpu(request); 572 trace_nbd_negotiate_handle_info_request(request, 573 nbd_info_lookup(request)); 574 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 575 * everything else is either a request we don't know or 576 * something we send regardless of request */ 577 switch (request) { 578 case NBD_INFO_NAME: 579 sendname = true; 580 break; 581 case NBD_INFO_BLOCK_SIZE: 582 blocksize = true; 583 break; 584 } 585 } 586 if (client->optlen) { 587 return nbd_reject_length(client, false, errp); 588 } 589 590 exp = nbd_export_find(name); 591 if (!exp) { 592 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 593 errp, "export '%s' not present", 594 name); 595 } 596 597 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 598 if (sendname) { 599 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 600 errp); 601 if (rc < 0) { 602 return rc; 603 } 604 } 605 606 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 607 * client request */ 608 if (exp->description) { 609 size_t len = strlen(exp->description); 610 611 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 612 len, exp->description, errp); 613 if (rc < 0) { 614 return rc; 615 } 616 } 617 618 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 619 * according to whether the client requested it, and according to 620 * whether this is OPT_INFO or OPT_GO. */ 621 /* minimum - 1 for back-compat, or actual if client will obey it. */ 622 if (client->opt == NBD_OPT_INFO || blocksize) { 623 check_align = sizes[0] = blk_get_request_alignment(exp->blk); 624 } else { 625 sizes[0] = 1; 626 } 627 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 628 /* preferred - Hard-code to 4096 for now. 629 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 630 sizes[1] = MAX(4096, sizes[0]); 631 /* maximum - At most 32M, but smaller as appropriate. */ 632 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE); 633 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 634 sizes[0] = cpu_to_be32(sizes[0]); 635 sizes[1] = cpu_to_be32(sizes[1]); 636 sizes[2] = cpu_to_be32(sizes[2]); 637 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 638 sizeof(sizes), sizes, errp); 639 if (rc < 0) { 640 return rc; 641 } 642 643 /* Send NBD_INFO_EXPORT always */ 644 myflags = exp->nbdflags; 645 if (client->structured_reply) { 646 myflags |= NBD_FLAG_SEND_DF; 647 } 648 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags); 649 stq_be_p(buf, exp->size); 650 stw_be_p(buf + 8, myflags); 651 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 652 sizeof(buf), buf, errp); 653 if (rc < 0) { 654 return rc; 655 } 656 657 /* 658 * If the client is just asking for NBD_OPT_INFO, but forgot to 659 * request block sizes in a situation that would impact 660 * performance, then return an error. But for NBD_OPT_GO, we 661 * tolerate all clients, regardless of alignments. 662 */ 663 if (client->opt == NBD_OPT_INFO && !blocksize && 664 blk_get_request_alignment(exp->blk) > 1) { 665 return nbd_negotiate_send_rep_err(client, 666 NBD_REP_ERR_BLOCK_SIZE_REQD, 667 errp, 668 "request NBD_INFO_BLOCK_SIZE to " 669 "use this export"); 670 } 671 672 /* Final reply */ 673 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 674 if (rc < 0) { 675 return rc; 676 } 677 678 if (client->opt == NBD_OPT_GO) { 679 client->exp = exp; 680 client->check_align = check_align; 681 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 682 nbd_export_get(client->exp); 683 nbd_check_meta_export(client); 684 rc = 1; 685 } 686 return rc; 687 } 688 689 690 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 691 * new channel for all further (now-encrypted) communication. */ 692 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 693 Error **errp) 694 { 695 QIOChannel *ioc; 696 QIOChannelTLS *tioc; 697 struct NBDTLSHandshakeData data = { 0 }; 698 699 assert(client->opt == NBD_OPT_STARTTLS); 700 701 trace_nbd_negotiate_handle_starttls(); 702 ioc = client->ioc; 703 704 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 705 return NULL; 706 } 707 708 tioc = qio_channel_tls_new_server(ioc, 709 client->tlscreds, 710 client->tlsauthz, 711 errp); 712 if (!tioc) { 713 return NULL; 714 } 715 716 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 717 trace_nbd_negotiate_handle_starttls_handshake(); 718 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 719 qio_channel_tls_handshake(tioc, 720 nbd_tls_handshake, 721 &data, 722 NULL, 723 NULL); 724 725 if (!data.complete) { 726 g_main_loop_run(data.loop); 727 } 728 g_main_loop_unref(data.loop); 729 if (data.error) { 730 object_unref(OBJECT(tioc)); 731 error_propagate(errp, data.error); 732 return NULL; 733 } 734 735 return QIO_CHANNEL(tioc); 736 } 737 738 /* nbd_negotiate_send_meta_context 739 * 740 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 741 * 742 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 743 */ 744 static int nbd_negotiate_send_meta_context(NBDClient *client, 745 const char *context, 746 uint32_t context_id, 747 Error **errp) 748 { 749 NBDOptionReplyMetaContext opt; 750 struct iovec iov[] = { 751 {.iov_base = &opt, .iov_len = sizeof(opt)}, 752 {.iov_base = (void *)context, .iov_len = strlen(context)} 753 }; 754 755 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 756 context_id = 0; 757 } 758 759 trace_nbd_negotiate_meta_query_reply(context, context_id); 760 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 761 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 762 stl_be_p(&opt.context_id, context_id); 763 764 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 765 } 766 767 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern. 768 * @match is never set to false. 769 * 770 * Return -errno on I/O error, 0 if option was completely handled by 771 * sending a reply about inconsistent lengths, or 1 on success. 772 * 773 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 774 * It only means that there are no errors. 775 */ 776 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match, 777 Error **errp) 778 { 779 int ret; 780 char *query; 781 size_t len = strlen(pattern); 782 783 assert(len); 784 785 query = g_malloc(len); 786 ret = nbd_opt_read(client, query, len, errp); 787 if (ret <= 0) { 788 g_free(query); 789 return ret; 790 } 791 792 if (strncmp(query, pattern, len) == 0) { 793 trace_nbd_negotiate_meta_query_parse(pattern); 794 *match = true; 795 } else { 796 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 797 } 798 g_free(query); 799 800 return 1; 801 } 802 803 /* 804 * Read @len bytes, and set @match to true if they match @pattern, or if @len 805 * is 0 and the client is performing _LIST_. @match is never set to false. 806 * 807 * Return -errno on I/O error, 0 if option was completely handled by 808 * sending a reply about inconsistent lengths, or 1 on success. 809 * 810 * Note: return code = 1 doesn't mean that we've read exactly @pattern. 811 * It only means that there are no errors. 812 */ 813 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 814 uint32_t len, bool *match, Error **errp) 815 { 816 if (len == 0) { 817 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 818 *match = true; 819 } 820 trace_nbd_negotiate_meta_query_parse("empty"); 821 return 1; 822 } 823 824 if (len != strlen(pattern)) { 825 trace_nbd_negotiate_meta_query_skip("different lengths"); 826 return nbd_opt_skip(client, len, errp); 827 } 828 829 return nbd_meta_pattern(client, pattern, match, errp); 830 } 831 832 /* nbd_meta_base_query 833 * 834 * Handle queries to 'base' namespace. For now, only the base:allocation 835 * context is available. 'len' is the amount of text remaining to be read from 836 * the current name, after the 'base:' portion has been stripped. 837 * 838 * Return -errno on I/O error, 0 if option was completely handled by 839 * sending a reply about inconsistent lengths, or 1 on success. 840 */ 841 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 842 uint32_t len, Error **errp) 843 { 844 return nbd_meta_empty_or_pattern(client, "allocation", len, 845 &meta->base_allocation, errp); 846 } 847 848 /* nbd_meta_bitmap_query 849 * 850 * Handle query to 'qemu:' namespace. 851 * @len is the amount of text remaining to be read from the current name, after 852 * the 'qemu:' portion has been stripped. 853 * 854 * Return -errno on I/O error, 0 if option was completely handled by 855 * sending a reply about inconsistent lengths, or 1 on success. */ 856 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 857 uint32_t len, Error **errp) 858 { 859 bool dirty_bitmap = false; 860 size_t dirty_bitmap_len = strlen("dirty-bitmap:"); 861 int ret; 862 863 if (!meta->exp->export_bitmap) { 864 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); 865 return nbd_opt_skip(client, len, errp); 866 } 867 868 if (len == 0) { 869 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 870 meta->bitmap = true; 871 } 872 trace_nbd_negotiate_meta_query_parse("empty"); 873 return 1; 874 } 875 876 if (len < dirty_bitmap_len) { 877 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 878 return nbd_opt_skip(client, len, errp); 879 } 880 881 len -= dirty_bitmap_len; 882 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp); 883 if (ret <= 0) { 884 return ret; 885 } 886 if (!dirty_bitmap) { 887 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:"); 888 return nbd_opt_skip(client, len, errp); 889 } 890 891 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 892 893 return nbd_meta_empty_or_pattern( 894 client, meta->exp->export_bitmap_context + 895 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp); 896 } 897 898 /* nbd_negotiate_meta_query 899 * 900 * Parse namespace name and call corresponding function to parse body of the 901 * query. 902 * 903 * The only supported namespace now is 'base'. 904 * 905 * The function aims not wasting time and memory to read long unknown namespace 906 * names. 907 * 908 * Return -errno on I/O error, 0 if option was completely handled by 909 * sending a reply about inconsistent lengths, or 1 on success. */ 910 static int nbd_negotiate_meta_query(NBDClient *client, 911 NBDExportMetaContexts *meta, Error **errp) 912 { 913 /* 914 * Both 'qemu' and 'base' namespaces have length = 5 including a 915 * colon. If another length namespace is later introduced, this 916 * should certainly be refactored. 917 */ 918 int ret; 919 size_t ns_len = 5; 920 char ns[5]; 921 uint32_t len; 922 923 ret = nbd_opt_read(client, &len, sizeof(len), errp); 924 if (ret <= 0) { 925 return ret; 926 } 927 len = cpu_to_be32(len); 928 929 if (len < ns_len) { 930 trace_nbd_negotiate_meta_query_skip("length too short"); 931 return nbd_opt_skip(client, len, errp); 932 } 933 934 len -= ns_len; 935 ret = nbd_opt_read(client, ns, ns_len, errp); 936 if (ret <= 0) { 937 return ret; 938 } 939 940 if (!strncmp(ns, "base:", ns_len)) { 941 trace_nbd_negotiate_meta_query_parse("base:"); 942 return nbd_meta_base_query(client, meta, len, errp); 943 } else if (!strncmp(ns, "qemu:", ns_len)) { 944 trace_nbd_negotiate_meta_query_parse("qemu:"); 945 return nbd_meta_qemu_query(client, meta, len, errp); 946 } 947 948 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 949 return nbd_opt_skip(client, len, errp); 950 } 951 952 /* nbd_negotiate_meta_queries 953 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 954 * 955 * Return -errno on I/O error, or 0 if option was completely handled. */ 956 static int nbd_negotiate_meta_queries(NBDClient *client, 957 NBDExportMetaContexts *meta, Error **errp) 958 { 959 int ret; 960 char export_name[NBD_MAX_NAME_SIZE + 1]; 961 NBDExportMetaContexts local_meta; 962 uint32_t nb_queries; 963 int i; 964 965 if (!client->structured_reply) { 966 return nbd_opt_invalid(client, errp, 967 "request option '%s' when structured reply " 968 "is not negotiated", 969 nbd_opt_lookup(client->opt)); 970 } 971 972 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 973 /* Only change the caller's meta on SET. */ 974 meta = &local_meta; 975 } 976 977 memset(meta, 0, sizeof(*meta)); 978 979 ret = nbd_opt_read_name(client, export_name, NULL, errp); 980 if (ret <= 0) { 981 return ret; 982 } 983 984 meta->exp = nbd_export_find(export_name); 985 if (meta->exp == NULL) { 986 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 987 "export '%s' not present", export_name); 988 } 989 990 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); 991 if (ret <= 0) { 992 return ret; 993 } 994 nb_queries = cpu_to_be32(nb_queries); 995 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 996 export_name, nb_queries); 997 998 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 999 /* enable all known contexts */ 1000 meta->base_allocation = true; 1001 meta->bitmap = !!meta->exp->export_bitmap; 1002 } else { 1003 for (i = 0; i < nb_queries; ++i) { 1004 ret = nbd_negotiate_meta_query(client, meta, errp); 1005 if (ret <= 0) { 1006 return ret; 1007 } 1008 } 1009 } 1010 1011 if (meta->base_allocation) { 1012 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1013 NBD_META_ID_BASE_ALLOCATION, 1014 errp); 1015 if (ret < 0) { 1016 return ret; 1017 } 1018 } 1019 1020 if (meta->bitmap) { 1021 ret = nbd_negotiate_send_meta_context(client, 1022 meta->exp->export_bitmap_context, 1023 NBD_META_ID_DIRTY_BITMAP, 1024 errp); 1025 if (ret < 0) { 1026 return ret; 1027 } 1028 } 1029 1030 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1031 if (ret == 0) { 1032 meta->valid = true; 1033 } 1034 1035 return ret; 1036 } 1037 1038 /* nbd_negotiate_options 1039 * Process all NBD_OPT_* client option commands, during fixed newstyle 1040 * negotiation. 1041 * Return: 1042 * -errno on error, errp is set 1043 * 0 on successful negotiation, errp is not set 1044 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1045 * errp is not set 1046 */ 1047 static int nbd_negotiate_options(NBDClient *client, Error **errp) 1048 { 1049 uint32_t flags; 1050 bool fixedNewstyle = false; 1051 bool no_zeroes = false; 1052 1053 /* Client sends: 1054 [ 0 .. 3] client flags 1055 1056 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1057 [ 0 .. 7] NBD_OPTS_MAGIC 1058 [ 8 .. 11] NBD option 1059 [12 .. 15] Data length 1060 ... Rest of request 1061 1062 [ 0 .. 7] NBD_OPTS_MAGIC 1063 [ 8 .. 11] Second NBD option 1064 [12 .. 15] Data length 1065 ... Rest of request 1066 */ 1067 1068 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1069 return -EIO; 1070 } 1071 trace_nbd_negotiate_options_flags(flags); 1072 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1073 fixedNewstyle = true; 1074 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1075 } 1076 if (flags & NBD_FLAG_C_NO_ZEROES) { 1077 no_zeroes = true; 1078 flags &= ~NBD_FLAG_C_NO_ZEROES; 1079 } 1080 if (flags != 0) { 1081 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1082 return -EINVAL; 1083 } 1084 1085 while (1) { 1086 int ret; 1087 uint32_t option, length; 1088 uint64_t magic; 1089 1090 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1091 return -EINVAL; 1092 } 1093 trace_nbd_negotiate_options_check_magic(magic); 1094 if (magic != NBD_OPTS_MAGIC) { 1095 error_setg(errp, "Bad magic received"); 1096 return -EINVAL; 1097 } 1098 1099 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1100 return -EINVAL; 1101 } 1102 client->opt = option; 1103 1104 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1105 return -EINVAL; 1106 } 1107 assert(!client->optlen); 1108 client->optlen = length; 1109 1110 if (length > NBD_MAX_BUFFER_SIZE) { 1111 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1112 length, NBD_MAX_BUFFER_SIZE); 1113 return -EINVAL; 1114 } 1115 1116 trace_nbd_negotiate_options_check_option(option, 1117 nbd_opt_lookup(option)); 1118 if (client->tlscreds && 1119 client->ioc == (QIOChannel *)client->sioc) { 1120 QIOChannel *tioc; 1121 if (!fixedNewstyle) { 1122 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1123 return -EINVAL; 1124 } 1125 switch (option) { 1126 case NBD_OPT_STARTTLS: 1127 if (length) { 1128 /* Unconditionally drop the connection if the client 1129 * can't start a TLS negotiation correctly */ 1130 return nbd_reject_length(client, true, errp); 1131 } 1132 tioc = nbd_negotiate_handle_starttls(client, errp); 1133 if (!tioc) { 1134 return -EIO; 1135 } 1136 ret = 0; 1137 object_unref(OBJECT(client->ioc)); 1138 client->ioc = QIO_CHANNEL(tioc); 1139 break; 1140 1141 case NBD_OPT_EXPORT_NAME: 1142 /* No way to return an error to client, so drop connection */ 1143 error_setg(errp, "Option 0x%x not permitted before TLS", 1144 option); 1145 return -EINVAL; 1146 1147 default: 1148 /* Let the client keep trying, unless they asked to 1149 * quit. Always try to give an error back to the 1150 * client; but when replying to OPT_ABORT, be aware 1151 * that the client may hang up before receiving the 1152 * error, in which case we are fine ignoring the 1153 * resulting EPIPE. */ 1154 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1155 option == NBD_OPT_ABORT ? NULL : errp, 1156 "Option 0x%" PRIx32 1157 " not permitted before TLS", option); 1158 if (option == NBD_OPT_ABORT) { 1159 return 1; 1160 } 1161 break; 1162 } 1163 } else if (fixedNewstyle) { 1164 switch (option) { 1165 case NBD_OPT_LIST: 1166 if (length) { 1167 ret = nbd_reject_length(client, false, errp); 1168 } else { 1169 ret = nbd_negotiate_handle_list(client, errp); 1170 } 1171 break; 1172 1173 case NBD_OPT_ABORT: 1174 /* NBD spec says we must try to reply before 1175 * disconnecting, but that we must also tolerate 1176 * guests that don't wait for our reply. */ 1177 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1178 return 1; 1179 1180 case NBD_OPT_EXPORT_NAME: 1181 return nbd_negotiate_handle_export_name(client, no_zeroes, 1182 errp); 1183 1184 case NBD_OPT_INFO: 1185 case NBD_OPT_GO: 1186 ret = nbd_negotiate_handle_info(client, errp); 1187 if (ret == 1) { 1188 assert(option == NBD_OPT_GO); 1189 return 0; 1190 } 1191 break; 1192 1193 case NBD_OPT_STARTTLS: 1194 if (length) { 1195 ret = nbd_reject_length(client, false, errp); 1196 } else if (client->tlscreds) { 1197 ret = nbd_negotiate_send_rep_err(client, 1198 NBD_REP_ERR_INVALID, errp, 1199 "TLS already enabled"); 1200 } else { 1201 ret = nbd_negotiate_send_rep_err(client, 1202 NBD_REP_ERR_POLICY, errp, 1203 "TLS not configured"); 1204 } 1205 break; 1206 1207 case NBD_OPT_STRUCTURED_REPLY: 1208 if (length) { 1209 ret = nbd_reject_length(client, false, errp); 1210 } else if (client->structured_reply) { 1211 ret = nbd_negotiate_send_rep_err( 1212 client, NBD_REP_ERR_INVALID, errp, 1213 "structured reply already negotiated"); 1214 } else { 1215 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1216 client->structured_reply = true; 1217 } 1218 break; 1219 1220 case NBD_OPT_LIST_META_CONTEXT: 1221 case NBD_OPT_SET_META_CONTEXT: 1222 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1223 errp); 1224 break; 1225 1226 default: 1227 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1228 "Unsupported option %" PRIu32 " (%s)", 1229 option, nbd_opt_lookup(option)); 1230 break; 1231 } 1232 } else { 1233 /* 1234 * If broken new-style we should drop the connection 1235 * for anything except NBD_OPT_EXPORT_NAME 1236 */ 1237 switch (option) { 1238 case NBD_OPT_EXPORT_NAME: 1239 return nbd_negotiate_handle_export_name(client, no_zeroes, 1240 errp); 1241 1242 default: 1243 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1244 option, nbd_opt_lookup(option)); 1245 return -EINVAL; 1246 } 1247 } 1248 if (ret < 0) { 1249 return ret; 1250 } 1251 } 1252 } 1253 1254 /* nbd_negotiate 1255 * Return: 1256 * -errno on error, errp is set 1257 * 0 on successful negotiation, errp is not set 1258 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1259 * errp is not set 1260 */ 1261 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1262 { 1263 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1264 int ret; 1265 1266 /* Old style negotiation header, no room for options 1267 [ 0 .. 7] passwd ("NBDMAGIC") 1268 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1269 [16 .. 23] size 1270 [24 .. 27] export flags (zero-extended) 1271 [28 .. 151] reserved (0) 1272 1273 New style negotiation header, client can send options 1274 [ 0 .. 7] passwd ("NBDMAGIC") 1275 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1276 [16 .. 17] server flags (0) 1277 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1278 */ 1279 1280 qio_channel_set_blocking(client->ioc, false, NULL); 1281 1282 trace_nbd_negotiate_begin(); 1283 memcpy(buf, "NBDMAGIC", 8); 1284 1285 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1286 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1287 1288 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1289 error_prepend(errp, "write failed: "); 1290 return -EINVAL; 1291 } 1292 ret = nbd_negotiate_options(client, errp); 1293 if (ret != 0) { 1294 if (ret < 0) { 1295 error_prepend(errp, "option negotiation failed: "); 1296 } 1297 return ret; 1298 } 1299 1300 /* Attach the channel to the same AioContext as the export */ 1301 if (client->exp && client->exp->ctx) { 1302 qio_channel_attach_aio_context(client->ioc, client->exp->ctx); 1303 } 1304 1305 assert(!client->optlen); 1306 trace_nbd_negotiate_success(); 1307 1308 return 0; 1309 } 1310 1311 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1312 Error **errp) 1313 { 1314 uint8_t buf[NBD_REQUEST_SIZE]; 1315 uint32_t magic; 1316 int ret; 1317 1318 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1319 if (ret < 0) { 1320 return ret; 1321 } 1322 1323 /* Request 1324 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1325 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1326 [ 6 .. 7] type (NBD_CMD_READ, ...) 1327 [ 8 .. 15] handle 1328 [16 .. 23] from 1329 [24 .. 27] len 1330 */ 1331 1332 magic = ldl_be_p(buf); 1333 request->flags = lduw_be_p(buf + 4); 1334 request->type = lduw_be_p(buf + 6); 1335 request->handle = ldq_be_p(buf + 8); 1336 request->from = ldq_be_p(buf + 16); 1337 request->len = ldl_be_p(buf + 24); 1338 1339 trace_nbd_receive_request(magic, request->flags, request->type, 1340 request->from, request->len); 1341 1342 if (magic != NBD_REQUEST_MAGIC) { 1343 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1344 return -EINVAL; 1345 } 1346 return 0; 1347 } 1348 1349 #define MAX_NBD_REQUESTS 16 1350 1351 void nbd_client_get(NBDClient *client) 1352 { 1353 client->refcount++; 1354 } 1355 1356 void nbd_client_put(NBDClient *client) 1357 { 1358 if (--client->refcount == 0) { 1359 /* The last reference should be dropped by client->close, 1360 * which is called by client_close. 1361 */ 1362 assert(client->closing); 1363 1364 qio_channel_detach_aio_context(client->ioc); 1365 object_unref(OBJECT(client->sioc)); 1366 object_unref(OBJECT(client->ioc)); 1367 if (client->tlscreds) { 1368 object_unref(OBJECT(client->tlscreds)); 1369 } 1370 g_free(client->tlsauthz); 1371 if (client->exp) { 1372 QTAILQ_REMOVE(&client->exp->clients, client, next); 1373 nbd_export_put(client->exp); 1374 } 1375 g_free(client); 1376 } 1377 } 1378 1379 static void client_close(NBDClient *client, bool negotiated) 1380 { 1381 if (client->closing) { 1382 return; 1383 } 1384 1385 client->closing = true; 1386 1387 /* Force requests to finish. They will drop their own references, 1388 * then we'll close the socket and free the NBDClient. 1389 */ 1390 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1391 NULL); 1392 1393 /* Also tell the client, so that they release their reference. */ 1394 if (client->close_fn) { 1395 client->close_fn(client, negotiated); 1396 } 1397 } 1398 1399 static NBDRequestData *nbd_request_get(NBDClient *client) 1400 { 1401 NBDRequestData *req; 1402 1403 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1404 client->nb_requests++; 1405 1406 req = g_new0(NBDRequestData, 1); 1407 nbd_client_get(client); 1408 req->client = client; 1409 return req; 1410 } 1411 1412 static void nbd_request_put(NBDRequestData *req) 1413 { 1414 NBDClient *client = req->client; 1415 1416 if (req->data) { 1417 qemu_vfree(req->data); 1418 } 1419 g_free(req); 1420 1421 client->nb_requests--; 1422 nbd_client_receive_next_request(client); 1423 1424 nbd_client_put(client); 1425 } 1426 1427 static void blk_aio_attached(AioContext *ctx, void *opaque) 1428 { 1429 NBDExport *exp = opaque; 1430 NBDClient *client; 1431 1432 trace_nbd_blk_aio_attached(exp->name, ctx); 1433 1434 exp->ctx = ctx; 1435 1436 QTAILQ_FOREACH(client, &exp->clients, next) { 1437 qio_channel_attach_aio_context(client->ioc, ctx); 1438 if (client->recv_coroutine) { 1439 aio_co_schedule(ctx, client->recv_coroutine); 1440 } 1441 if (client->send_coroutine) { 1442 aio_co_schedule(ctx, client->send_coroutine); 1443 } 1444 } 1445 } 1446 1447 static void blk_aio_detach(void *opaque) 1448 { 1449 NBDExport *exp = opaque; 1450 NBDClient *client; 1451 1452 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1453 1454 QTAILQ_FOREACH(client, &exp->clients, next) { 1455 qio_channel_detach_aio_context(client->ioc); 1456 } 1457 1458 exp->ctx = NULL; 1459 } 1460 1461 static void nbd_eject_notifier(Notifier *n, void *data) 1462 { 1463 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1464 AioContext *aio_context; 1465 1466 aio_context = exp->ctx; 1467 aio_context_acquire(aio_context); 1468 nbd_export_close(exp); 1469 aio_context_release(aio_context); 1470 } 1471 1472 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, 1473 uint64_t size, const char *name, const char *desc, 1474 const char *bitmap, bool readonly, bool shared, 1475 void (*close)(NBDExport *), bool writethrough, 1476 BlockBackend *on_eject_blk, Error **errp) 1477 { 1478 AioContext *ctx; 1479 BlockBackend *blk; 1480 NBDExport *exp = g_new0(NBDExport, 1); 1481 uint64_t perm; 1482 int ret; 1483 1484 /* 1485 * NBD exports are used for non-shared storage migration. Make sure 1486 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1487 * access since the export could be available before migration handover. 1488 * ctx was acquired in the caller. 1489 */ 1490 assert(name); 1491 ctx = bdrv_get_aio_context(bs); 1492 bdrv_invalidate_cache(bs, NULL); 1493 1494 /* Don't allow resize while the NBD server is running, otherwise we don't 1495 * care what happens with the node. */ 1496 perm = BLK_PERM_CONSISTENT_READ; 1497 if (!readonly) { 1498 perm |= BLK_PERM_WRITE; 1499 } 1500 blk = blk_new(ctx, perm, 1501 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1502 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1503 ret = blk_insert_bs(blk, bs, errp); 1504 if (ret < 0) { 1505 goto fail; 1506 } 1507 blk_set_enable_write_cache(blk, !writethrough); 1508 blk_set_allow_aio_context_change(blk, true); 1509 1510 exp->refcount = 1; 1511 QTAILQ_INIT(&exp->clients); 1512 exp->blk = blk; 1513 assert(dev_offset <= INT64_MAX); 1514 exp->dev_offset = dev_offset; 1515 exp->name = g_strdup(name); 1516 exp->description = g_strdup(desc); 1517 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1518 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1519 if (readonly) { 1520 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1521 if (shared) { 1522 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1523 } 1524 } else { 1525 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1526 NBD_FLAG_SEND_FAST_ZERO); 1527 } 1528 assert(size <= INT64_MAX - dev_offset); 1529 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1530 1531 if (bitmap) { 1532 BdrvDirtyBitmap *bm = NULL; 1533 1534 while (true) { 1535 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1536 if (bm != NULL || bs->backing == NULL) { 1537 break; 1538 } 1539 1540 bs = bs->backing->bs; 1541 } 1542 1543 if (bm == NULL) { 1544 error_setg(errp, "Bitmap '%s' is not found", bitmap); 1545 goto fail; 1546 } 1547 1548 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1549 goto fail; 1550 } 1551 1552 if (readonly && bdrv_is_writable(bs) && 1553 bdrv_dirty_bitmap_enabled(bm)) { 1554 error_setg(errp, 1555 "Enabled bitmap '%s' incompatible with readonly export", 1556 bitmap); 1557 goto fail; 1558 } 1559 1560 bdrv_dirty_bitmap_set_busy(bm, true); 1561 exp->export_bitmap = bm; 1562 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1563 bitmap); 1564 } 1565 1566 exp->close = close; 1567 exp->ctx = ctx; 1568 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1569 1570 if (on_eject_blk) { 1571 blk_ref(on_eject_blk); 1572 exp->eject_notifier_blk = on_eject_blk; 1573 exp->eject_notifier.notify = nbd_eject_notifier; 1574 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1575 } 1576 QTAILQ_INSERT_TAIL(&exports, exp, next); 1577 nbd_export_get(exp); 1578 return exp; 1579 1580 fail: 1581 blk_unref(blk); 1582 g_free(exp->name); 1583 g_free(exp->description); 1584 g_free(exp); 1585 return NULL; 1586 } 1587 1588 NBDExport *nbd_export_find(const char *name) 1589 { 1590 NBDExport *exp; 1591 QTAILQ_FOREACH(exp, &exports, next) { 1592 if (strcmp(name, exp->name) == 0) { 1593 return exp; 1594 } 1595 } 1596 1597 return NULL; 1598 } 1599 1600 AioContext * 1601 nbd_export_aio_context(NBDExport *exp) 1602 { 1603 return exp->ctx; 1604 } 1605 1606 void nbd_export_close(NBDExport *exp) 1607 { 1608 NBDClient *client, *next; 1609 1610 nbd_export_get(exp); 1611 /* 1612 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1613 * close mode that stops advertising the export to new clients but 1614 * still permits existing clients to run to completion? Because of 1615 * that possibility, nbd_export_close() can be called more than 1616 * once on an export. 1617 */ 1618 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1619 client_close(client, true); 1620 } 1621 if (exp->name) { 1622 nbd_export_put(exp); 1623 g_free(exp->name); 1624 exp->name = NULL; 1625 QTAILQ_REMOVE(&exports, exp, next); 1626 } 1627 g_free(exp->description); 1628 exp->description = NULL; 1629 nbd_export_put(exp); 1630 } 1631 1632 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1633 { 1634 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1635 nbd_export_close(exp); 1636 return; 1637 } 1638 1639 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1640 1641 error_setg(errp, "export '%s' still in use", exp->name); 1642 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1643 } 1644 1645 void nbd_export_get(NBDExport *exp) 1646 { 1647 assert(exp->refcount > 0); 1648 exp->refcount++; 1649 } 1650 1651 void nbd_export_put(NBDExport *exp) 1652 { 1653 assert(exp->refcount > 0); 1654 if (exp->refcount == 1) { 1655 nbd_export_close(exp); 1656 } 1657 1658 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1659 * if someone calls nbd_export_put() on named export not through 1660 * nbd_export_set_name() when refcount is 1. So, let's assert that 1661 * it is > 0. 1662 */ 1663 assert(exp->refcount > 0); 1664 if (--exp->refcount == 0) { 1665 assert(exp->name == NULL); 1666 assert(exp->description == NULL); 1667 1668 if (exp->close) { 1669 exp->close(exp); 1670 } 1671 1672 if (exp->blk) { 1673 if (exp->eject_notifier_blk) { 1674 notifier_remove(&exp->eject_notifier); 1675 blk_unref(exp->eject_notifier_blk); 1676 } 1677 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1678 blk_aio_detach, exp); 1679 blk_unref(exp->blk); 1680 exp->blk = NULL; 1681 } 1682 1683 if (exp->export_bitmap) { 1684 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); 1685 g_free(exp->export_bitmap_context); 1686 } 1687 1688 g_free(exp); 1689 } 1690 } 1691 1692 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1693 { 1694 return exp->blk; 1695 } 1696 1697 void nbd_export_close_all(void) 1698 { 1699 NBDExport *exp, *next; 1700 AioContext *aio_context; 1701 1702 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1703 aio_context = exp->ctx; 1704 aio_context_acquire(aio_context); 1705 nbd_export_close(exp); 1706 aio_context_release(aio_context); 1707 } 1708 } 1709 1710 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1711 unsigned niov, Error **errp) 1712 { 1713 int ret; 1714 1715 g_assert(qemu_in_coroutine()); 1716 qemu_co_mutex_lock(&client->send_lock); 1717 client->send_coroutine = qemu_coroutine_self(); 1718 1719 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1720 1721 client->send_coroutine = NULL; 1722 qemu_co_mutex_unlock(&client->send_lock); 1723 1724 return ret; 1725 } 1726 1727 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1728 uint64_t handle) 1729 { 1730 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1731 stl_be_p(&reply->error, error); 1732 stq_be_p(&reply->handle, handle); 1733 } 1734 1735 static int nbd_co_send_simple_reply(NBDClient *client, 1736 uint64_t handle, 1737 uint32_t error, 1738 void *data, 1739 size_t len, 1740 Error **errp) 1741 { 1742 NBDSimpleReply reply; 1743 int nbd_err = system_errno_to_nbd_errno(error); 1744 struct iovec iov[] = { 1745 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1746 {.iov_base = data, .iov_len = len} 1747 }; 1748 1749 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1750 len); 1751 set_be_simple_reply(&reply, nbd_err, handle); 1752 1753 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1754 } 1755 1756 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1757 uint16_t type, uint64_t handle, uint32_t length) 1758 { 1759 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1760 stw_be_p(&chunk->flags, flags); 1761 stw_be_p(&chunk->type, type); 1762 stq_be_p(&chunk->handle, handle); 1763 stl_be_p(&chunk->length, length); 1764 } 1765 1766 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1767 uint64_t handle, 1768 Error **errp) 1769 { 1770 NBDStructuredReplyChunk chunk; 1771 struct iovec iov[] = { 1772 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1773 }; 1774 1775 trace_nbd_co_send_structured_done(handle); 1776 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1777 1778 return nbd_co_send_iov(client, iov, 1, errp); 1779 } 1780 1781 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1782 uint64_t handle, 1783 uint64_t offset, 1784 void *data, 1785 size_t size, 1786 bool final, 1787 Error **errp) 1788 { 1789 NBDStructuredReadData chunk; 1790 struct iovec iov[] = { 1791 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1792 {.iov_base = data, .iov_len = size} 1793 }; 1794 1795 assert(size); 1796 trace_nbd_co_send_structured_read(handle, offset, data, size); 1797 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1798 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1799 sizeof(chunk) - sizeof(chunk.h) + size); 1800 stq_be_p(&chunk.offset, offset); 1801 1802 return nbd_co_send_iov(client, iov, 2, errp); 1803 } 1804 1805 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1806 uint64_t handle, 1807 uint32_t error, 1808 const char *msg, 1809 Error **errp) 1810 { 1811 NBDStructuredError chunk; 1812 int nbd_err = system_errno_to_nbd_errno(error); 1813 struct iovec iov[] = { 1814 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1815 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1816 }; 1817 1818 assert(nbd_err); 1819 trace_nbd_co_send_structured_error(handle, nbd_err, 1820 nbd_err_lookup(nbd_err), msg ? msg : ""); 1821 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1822 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1823 stl_be_p(&chunk.error, nbd_err); 1824 stw_be_p(&chunk.message_length, iov[1].iov_len); 1825 1826 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1827 } 1828 1829 /* Do a sparse read and send the structured reply to the client. 1830 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1831 * reported to the client, at which point this function succeeds. 1832 */ 1833 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1834 uint64_t handle, 1835 uint64_t offset, 1836 uint8_t *data, 1837 size_t size, 1838 Error **errp) 1839 { 1840 int ret = 0; 1841 NBDExport *exp = client->exp; 1842 size_t progress = 0; 1843 1844 while (progress < size) { 1845 int64_t pnum; 1846 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1847 offset + progress, 1848 size - progress, &pnum, NULL, 1849 NULL); 1850 bool final; 1851 1852 if (status < 0) { 1853 char *msg = g_strdup_printf("unable to check for holes: %s", 1854 strerror(-status)); 1855 1856 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1857 errp); 1858 g_free(msg); 1859 return ret; 1860 } 1861 assert(pnum && pnum <= size - progress); 1862 final = progress + pnum == size; 1863 if (status & BDRV_BLOCK_ZERO) { 1864 NBDStructuredReadHole chunk; 1865 struct iovec iov[] = { 1866 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1867 }; 1868 1869 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1870 pnum); 1871 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1872 NBD_REPLY_TYPE_OFFSET_HOLE, 1873 handle, sizeof(chunk) - sizeof(chunk.h)); 1874 stq_be_p(&chunk.offset, offset + progress); 1875 stl_be_p(&chunk.length, pnum); 1876 ret = nbd_co_send_iov(client, iov, 1, errp); 1877 } else { 1878 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1879 data + progress, pnum); 1880 if (ret < 0) { 1881 error_setg_errno(errp, -ret, "reading from file failed"); 1882 break; 1883 } 1884 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1885 data + progress, pnum, final, 1886 errp); 1887 } 1888 1889 if (ret < 0) { 1890 break; 1891 } 1892 progress += pnum; 1893 } 1894 return ret; 1895 } 1896 1897 /* 1898 * Populate @extents from block status. Update @bytes to be the actual 1899 * length encoded (which may be smaller than the original), and update 1900 * @nb_extents to the number of extents used. 1901 * 1902 * Returns zero on success and -errno on bdrv_block_status_above failure. 1903 */ 1904 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1905 uint64_t *bytes, NBDExtent *extents, 1906 unsigned int *nb_extents) 1907 { 1908 uint64_t remaining_bytes = *bytes; 1909 NBDExtent *extent = extents, *extents_end = extents + *nb_extents; 1910 bool first_extent = true; 1911 1912 assert(*nb_extents); 1913 while (remaining_bytes) { 1914 uint32_t flags; 1915 int64_t num; 1916 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, 1917 &num, NULL, NULL); 1918 1919 if (ret < 0) { 1920 return ret; 1921 } 1922 1923 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1924 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1925 1926 if (first_extent) { 1927 extent->flags = flags; 1928 extent->length = num; 1929 first_extent = false; 1930 } else if (flags == extent->flags) { 1931 /* extend current extent */ 1932 extent->length += num; 1933 } else { 1934 if (extent + 1 == extents_end) { 1935 break; 1936 } 1937 1938 /* start new extent */ 1939 extent++; 1940 extent->flags = flags; 1941 extent->length = num; 1942 } 1943 offset += num; 1944 remaining_bytes -= num; 1945 } 1946 1947 extents_end = extent + 1; 1948 1949 for (extent = extents; extent < extents_end; extent++) { 1950 extent->flags = cpu_to_be32(extent->flags); 1951 extent->length = cpu_to_be32(extent->length); 1952 } 1953 1954 *bytes -= remaining_bytes; 1955 *nb_extents = extents_end - extents; 1956 1957 return 0; 1958 } 1959 1960 /* nbd_co_send_extents 1961 * 1962 * @length is only for tracing purposes (and may be smaller or larger 1963 * than the client's original request). @last controls whether 1964 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in 1965 * big-endian format. 1966 */ 1967 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1968 NBDExtent *extents, unsigned int nb_extents, 1969 uint64_t length, bool last, 1970 uint32_t context_id, Error **errp) 1971 { 1972 NBDStructuredMeta chunk; 1973 1974 struct iovec iov[] = { 1975 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1976 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} 1977 }; 1978 1979 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); 1980 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1981 NBD_REPLY_TYPE_BLOCK_STATUS, 1982 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1983 stl_be_p(&chunk.context_id, context_id); 1984 1985 return nbd_co_send_iov(client, iov, 2, errp); 1986 } 1987 1988 /* Get block status from the exported device and send it to the client */ 1989 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1990 BlockDriverState *bs, uint64_t offset, 1991 uint32_t length, bool dont_fragment, 1992 bool last, uint32_t context_id, 1993 Error **errp) 1994 { 1995 int ret; 1996 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 1997 NBDExtent *extents = g_new(NBDExtent, nb_extents); 1998 uint64_t final_length = length; 1999 2000 ret = blockstatus_to_extents(bs, offset, &final_length, extents, 2001 &nb_extents); 2002 if (ret < 0) { 2003 g_free(extents); 2004 return nbd_co_send_structured_error( 2005 client, handle, -ret, "can't get block status", errp); 2006 } 2007 2008 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2009 final_length, last, context_id, errp); 2010 2011 g_free(extents); 2012 2013 return ret; 2014 } 2015 2016 /* 2017 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the 2018 * final extent may exceed the original @length. Store in @length the 2019 * byte length encoded (which may be smaller or larger than the 2020 * original), and return the number of extents used. 2021 */ 2022 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, 2023 uint64_t *length, NBDExtent *extents, 2024 unsigned int nb_extents, 2025 bool dont_fragment) 2026 { 2027 uint64_t begin = offset, end = offset; 2028 uint64_t overall_end = offset + *length; 2029 unsigned int i = 0; 2030 BdrvDirtyBitmapIter *it; 2031 bool dirty; 2032 2033 bdrv_dirty_bitmap_lock(bitmap); 2034 2035 it = bdrv_dirty_iter_new(bitmap); 2036 dirty = bdrv_dirty_bitmap_get_locked(bitmap, offset); 2037 2038 assert(begin < overall_end && nb_extents); 2039 while (begin < overall_end && i < nb_extents) { 2040 bool next_dirty = !dirty; 2041 2042 if (dirty) { 2043 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX); 2044 } else { 2045 bdrv_set_dirty_iter(it, begin); 2046 end = bdrv_dirty_iter_next(it); 2047 } 2048 if (end == -1 || end - begin > UINT32_MAX) { 2049 /* Cap to an aligned value < 4G beyond begin. */ 2050 end = MIN(bdrv_dirty_bitmap_size(bitmap), 2051 begin + UINT32_MAX + 1 - 2052 bdrv_dirty_bitmap_granularity(bitmap)); 2053 next_dirty = dirty; 2054 } 2055 if (dont_fragment && end > overall_end) { 2056 end = overall_end; 2057 } 2058 2059 extents[i].length = cpu_to_be32(end - begin); 2060 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); 2061 i++; 2062 begin = end; 2063 dirty = next_dirty; 2064 } 2065 2066 bdrv_dirty_iter_free(it); 2067 2068 bdrv_dirty_bitmap_unlock(bitmap); 2069 2070 assert(offset < end); 2071 *length = end - offset; 2072 return i; 2073 } 2074 2075 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2076 BdrvDirtyBitmap *bitmap, uint64_t offset, 2077 uint32_t length, bool dont_fragment, bool last, 2078 uint32_t context_id, Error **errp) 2079 { 2080 int ret; 2081 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2082 NBDExtent *extents = g_new(NBDExtent, nb_extents); 2083 uint64_t final_length = length; 2084 2085 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, 2086 nb_extents, dont_fragment); 2087 2088 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2089 final_length, last, context_id, errp); 2090 2091 g_free(extents); 2092 2093 return ret; 2094 } 2095 2096 /* nbd_co_receive_request 2097 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2098 * connection right away, and any other negative value to report an error to 2099 * the client (although the caller may still need to disconnect after reporting 2100 * the error). 2101 */ 2102 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2103 Error **errp) 2104 { 2105 NBDClient *client = req->client; 2106 int valid_flags; 2107 2108 g_assert(qemu_in_coroutine()); 2109 assert(client->recv_coroutine == qemu_coroutine_self()); 2110 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2111 return -EIO; 2112 } 2113 2114 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2115 nbd_cmd_lookup(request->type)); 2116 2117 if (request->type != NBD_CMD_WRITE) { 2118 /* No payload, we are ready to read the next request. */ 2119 req->complete = true; 2120 } 2121 2122 if (request->type == NBD_CMD_DISC) { 2123 /* Special case: we're going to disconnect without a reply, 2124 * whether or not flags, from, or len are bogus */ 2125 return -EIO; 2126 } 2127 2128 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2129 request->type == NBD_CMD_CACHE) 2130 { 2131 if (request->len > NBD_MAX_BUFFER_SIZE) { 2132 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2133 request->len, NBD_MAX_BUFFER_SIZE); 2134 return -EINVAL; 2135 } 2136 2137 if (request->type != NBD_CMD_CACHE) { 2138 req->data = blk_try_blockalign(client->exp->blk, request->len); 2139 if (req->data == NULL) { 2140 error_setg(errp, "No memory"); 2141 return -ENOMEM; 2142 } 2143 } 2144 } 2145 2146 if (request->type == NBD_CMD_WRITE) { 2147 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2148 errp) < 0) 2149 { 2150 return -EIO; 2151 } 2152 req->complete = true; 2153 2154 trace_nbd_co_receive_request_payload_received(request->handle, 2155 request->len); 2156 } 2157 2158 /* Sanity checks. */ 2159 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2160 (request->type == NBD_CMD_WRITE || 2161 request->type == NBD_CMD_WRITE_ZEROES || 2162 request->type == NBD_CMD_TRIM)) { 2163 error_setg(errp, "Export is read-only"); 2164 return -EROFS; 2165 } 2166 if (request->from > client->exp->size || 2167 request->len > client->exp->size - request->from) { 2168 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2169 ", Size: %" PRIu64, request->from, request->len, 2170 client->exp->size); 2171 return (request->type == NBD_CMD_WRITE || 2172 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2173 } 2174 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2175 client->check_align)) { 2176 /* 2177 * The block layer gracefully handles unaligned requests, but 2178 * it's still worth tracing client non-compliance 2179 */ 2180 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2181 request->from, 2182 request->len, 2183 client->check_align); 2184 } 2185 valid_flags = NBD_CMD_FLAG_FUA; 2186 if (request->type == NBD_CMD_READ && client->structured_reply) { 2187 valid_flags |= NBD_CMD_FLAG_DF; 2188 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2189 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2190 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2191 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2192 } 2193 if (request->flags & ~valid_flags) { 2194 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2195 nbd_cmd_lookup(request->type), request->flags); 2196 return -EINVAL; 2197 } 2198 2199 return 0; 2200 } 2201 2202 /* Send simple reply without a payload, or a structured error 2203 * @error_msg is ignored if @ret >= 0 2204 * Returns 0 if connection is still live, -errno on failure to talk to client 2205 */ 2206 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2207 uint64_t handle, 2208 int ret, 2209 const char *error_msg, 2210 Error **errp) 2211 { 2212 if (client->structured_reply && ret < 0) { 2213 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2214 errp); 2215 } else { 2216 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2217 NULL, 0, errp); 2218 } 2219 } 2220 2221 /* Handle NBD_CMD_READ request. 2222 * Return -errno if sending fails. Other errors are reported directly to the 2223 * client as an error reply. */ 2224 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2225 uint8_t *data, Error **errp) 2226 { 2227 int ret; 2228 NBDExport *exp = client->exp; 2229 2230 assert(request->type == NBD_CMD_READ); 2231 2232 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2233 if (request->flags & NBD_CMD_FLAG_FUA) { 2234 ret = blk_co_flush(exp->blk); 2235 if (ret < 0) { 2236 return nbd_send_generic_reply(client, request->handle, ret, 2237 "flush failed", errp); 2238 } 2239 } 2240 2241 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2242 request->len) 2243 { 2244 return nbd_co_send_sparse_read(client, request->handle, request->from, 2245 data, request->len, errp); 2246 } 2247 2248 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, 2249 request->len); 2250 if (ret < 0) { 2251 return nbd_send_generic_reply(client, request->handle, ret, 2252 "reading from file failed", errp); 2253 } 2254 2255 if (client->structured_reply) { 2256 if (request->len) { 2257 return nbd_co_send_structured_read(client, request->handle, 2258 request->from, data, 2259 request->len, true, errp); 2260 } else { 2261 return nbd_co_send_structured_done(client, request->handle, errp); 2262 } 2263 } else { 2264 return nbd_co_send_simple_reply(client, request->handle, 0, 2265 data, request->len, errp); 2266 } 2267 } 2268 2269 /* 2270 * nbd_do_cmd_cache 2271 * 2272 * Handle NBD_CMD_CACHE request. 2273 * Return -errno if sending fails. Other errors are reported directly to the 2274 * client as an error reply. 2275 */ 2276 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2277 Error **errp) 2278 { 2279 int ret; 2280 NBDExport *exp = client->exp; 2281 2282 assert(request->type == NBD_CMD_CACHE); 2283 2284 ret = blk_co_preadv(exp->blk, request->from + exp->dev_offset, request->len, 2285 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2286 2287 return nbd_send_generic_reply(client, request->handle, ret, 2288 "caching data failed", errp); 2289 } 2290 2291 /* Handle NBD request. 2292 * Return -errno if sending fails. Other errors are reported directly to the 2293 * client as an error reply. */ 2294 static coroutine_fn int nbd_handle_request(NBDClient *client, 2295 NBDRequest *request, 2296 uint8_t *data, Error **errp) 2297 { 2298 int ret; 2299 int flags; 2300 NBDExport *exp = client->exp; 2301 char *msg; 2302 2303 switch (request->type) { 2304 case NBD_CMD_CACHE: 2305 return nbd_do_cmd_cache(client, request, errp); 2306 2307 case NBD_CMD_READ: 2308 return nbd_do_cmd_read(client, request, data, errp); 2309 2310 case NBD_CMD_WRITE: 2311 flags = 0; 2312 if (request->flags & NBD_CMD_FLAG_FUA) { 2313 flags |= BDRV_REQ_FUA; 2314 } 2315 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, 2316 data, request->len, flags); 2317 return nbd_send_generic_reply(client, request->handle, ret, 2318 "writing to file failed", errp); 2319 2320 case NBD_CMD_WRITE_ZEROES: 2321 flags = 0; 2322 if (request->flags & NBD_CMD_FLAG_FUA) { 2323 flags |= BDRV_REQ_FUA; 2324 } 2325 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2326 flags |= BDRV_REQ_MAY_UNMAP; 2327 } 2328 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2329 flags |= BDRV_REQ_NO_FALLBACK; 2330 } 2331 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, 2332 request->len, flags); 2333 return nbd_send_generic_reply(client, request->handle, ret, 2334 "writing to file failed", errp); 2335 2336 case NBD_CMD_DISC: 2337 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2338 abort(); 2339 2340 case NBD_CMD_FLUSH: 2341 ret = blk_co_flush(exp->blk); 2342 return nbd_send_generic_reply(client, request->handle, ret, 2343 "flush failed", errp); 2344 2345 case NBD_CMD_TRIM: 2346 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, 2347 request->len); 2348 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { 2349 ret = blk_co_flush(exp->blk); 2350 } 2351 return nbd_send_generic_reply(client, request->handle, ret, 2352 "discard failed", errp); 2353 2354 case NBD_CMD_BLOCK_STATUS: 2355 if (!request->len) { 2356 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2357 "need non-zero length", errp); 2358 } 2359 if (client->export_meta.valid && 2360 (client->export_meta.base_allocation || 2361 client->export_meta.bitmap)) 2362 { 2363 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2364 2365 if (client->export_meta.base_allocation) { 2366 ret = nbd_co_send_block_status(client, request->handle, 2367 blk_bs(exp->blk), request->from, 2368 request->len, dont_fragment, 2369 !client->export_meta.bitmap, 2370 NBD_META_ID_BASE_ALLOCATION, 2371 errp); 2372 if (ret < 0) { 2373 return ret; 2374 } 2375 } 2376 2377 if (client->export_meta.bitmap) { 2378 ret = nbd_co_send_bitmap(client, request->handle, 2379 client->exp->export_bitmap, 2380 request->from, request->len, 2381 dont_fragment, 2382 true, NBD_META_ID_DIRTY_BITMAP, errp); 2383 if (ret < 0) { 2384 return ret; 2385 } 2386 } 2387 2388 return ret; 2389 } else { 2390 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2391 "CMD_BLOCK_STATUS not negotiated", 2392 errp); 2393 } 2394 2395 default: 2396 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2397 request->type); 2398 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2399 errp); 2400 g_free(msg); 2401 return ret; 2402 } 2403 } 2404 2405 /* Owns a reference to the NBDClient passed as opaque. */ 2406 static coroutine_fn void nbd_trip(void *opaque) 2407 { 2408 NBDClient *client = opaque; 2409 NBDRequestData *req; 2410 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2411 int ret; 2412 Error *local_err = NULL; 2413 2414 trace_nbd_trip(); 2415 if (client->closing) { 2416 nbd_client_put(client); 2417 return; 2418 } 2419 2420 req = nbd_request_get(client); 2421 ret = nbd_co_receive_request(req, &request, &local_err); 2422 client->recv_coroutine = NULL; 2423 2424 if (client->closing) { 2425 /* 2426 * The client may be closed when we are blocked in 2427 * nbd_co_receive_request() 2428 */ 2429 goto done; 2430 } 2431 2432 nbd_client_receive_next_request(client); 2433 if (ret == -EIO) { 2434 goto disconnect; 2435 } 2436 2437 if (ret < 0) { 2438 /* It wans't -EIO, so, according to nbd_co_receive_request() 2439 * semantics, we should return the error to the client. */ 2440 Error *export_err = local_err; 2441 2442 local_err = NULL; 2443 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2444 error_get_pretty(export_err), &local_err); 2445 error_free(export_err); 2446 } else { 2447 ret = nbd_handle_request(client, &request, req->data, &local_err); 2448 } 2449 if (ret < 0) { 2450 error_prepend(&local_err, "Failed to send reply: "); 2451 goto disconnect; 2452 } 2453 2454 /* We must disconnect after NBD_CMD_WRITE if we did not 2455 * read the payload. 2456 */ 2457 if (!req->complete) { 2458 error_setg(&local_err, "Request handling failed in intermediate state"); 2459 goto disconnect; 2460 } 2461 2462 done: 2463 nbd_request_put(req); 2464 nbd_client_put(client); 2465 return; 2466 2467 disconnect: 2468 if (local_err) { 2469 error_reportf_err(local_err, "Disconnect client, due to: "); 2470 } 2471 nbd_request_put(req); 2472 client_close(client, true); 2473 nbd_client_put(client); 2474 } 2475 2476 static void nbd_client_receive_next_request(NBDClient *client) 2477 { 2478 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2479 nbd_client_get(client); 2480 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2481 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 2482 } 2483 } 2484 2485 static coroutine_fn void nbd_co_client_start(void *opaque) 2486 { 2487 NBDClient *client = opaque; 2488 Error *local_err = NULL; 2489 2490 qemu_co_mutex_init(&client->send_lock); 2491 2492 if (nbd_negotiate(client, &local_err)) { 2493 if (local_err) { 2494 error_report_err(local_err); 2495 } 2496 client_close(client, false); 2497 return; 2498 } 2499 2500 nbd_client_receive_next_request(client); 2501 } 2502 2503 /* 2504 * Create a new client listener using the given channel @sioc. 2505 * Begin servicing it in a coroutine. When the connection closes, call 2506 * @close_fn with an indication of whether the client completed negotiation. 2507 */ 2508 void nbd_client_new(QIOChannelSocket *sioc, 2509 QCryptoTLSCreds *tlscreds, 2510 const char *tlsauthz, 2511 void (*close_fn)(NBDClient *, bool)) 2512 { 2513 NBDClient *client; 2514 Coroutine *co; 2515 2516 client = g_new0(NBDClient, 1); 2517 client->refcount = 1; 2518 client->tlscreds = tlscreds; 2519 if (tlscreds) { 2520 object_ref(OBJECT(client->tlscreds)); 2521 } 2522 client->tlsauthz = g_strdup(tlsauthz); 2523 client->sioc = sioc; 2524 object_ref(OBJECT(client->sioc)); 2525 client->ioc = QIO_CHANNEL(sioc); 2526 object_ref(OBJECT(client->ioc)); 2527 client->close_fn = close_fn; 2528 2529 co = qemu_coroutine_create(nbd_co_client_start, client); 2530 qemu_coroutine_enter(co); 2531 } 2532