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 assert(!client->optlen); 1301 trace_nbd_negotiate_success(); 1302 1303 return 0; 1304 } 1305 1306 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1307 Error **errp) 1308 { 1309 uint8_t buf[NBD_REQUEST_SIZE]; 1310 uint32_t magic; 1311 int ret; 1312 1313 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1314 if (ret < 0) { 1315 return ret; 1316 } 1317 1318 /* Request 1319 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1320 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1321 [ 6 .. 7] type (NBD_CMD_READ, ...) 1322 [ 8 .. 15] handle 1323 [16 .. 23] from 1324 [24 .. 27] len 1325 */ 1326 1327 magic = ldl_be_p(buf); 1328 request->flags = lduw_be_p(buf + 4); 1329 request->type = lduw_be_p(buf + 6); 1330 request->handle = ldq_be_p(buf + 8); 1331 request->from = ldq_be_p(buf + 16); 1332 request->len = ldl_be_p(buf + 24); 1333 1334 trace_nbd_receive_request(magic, request->flags, request->type, 1335 request->from, request->len); 1336 1337 if (magic != NBD_REQUEST_MAGIC) { 1338 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1339 return -EINVAL; 1340 } 1341 return 0; 1342 } 1343 1344 #define MAX_NBD_REQUESTS 16 1345 1346 void nbd_client_get(NBDClient *client) 1347 { 1348 client->refcount++; 1349 } 1350 1351 void nbd_client_put(NBDClient *client) 1352 { 1353 if (--client->refcount == 0) { 1354 /* The last reference should be dropped by client->close, 1355 * which is called by client_close. 1356 */ 1357 assert(client->closing); 1358 1359 qio_channel_detach_aio_context(client->ioc); 1360 object_unref(OBJECT(client->sioc)); 1361 object_unref(OBJECT(client->ioc)); 1362 if (client->tlscreds) { 1363 object_unref(OBJECT(client->tlscreds)); 1364 } 1365 g_free(client->tlsauthz); 1366 if (client->exp) { 1367 QTAILQ_REMOVE(&client->exp->clients, client, next); 1368 nbd_export_put(client->exp); 1369 } 1370 g_free(client); 1371 } 1372 } 1373 1374 static void client_close(NBDClient *client, bool negotiated) 1375 { 1376 if (client->closing) { 1377 return; 1378 } 1379 1380 client->closing = true; 1381 1382 /* Force requests to finish. They will drop their own references, 1383 * then we'll close the socket and free the NBDClient. 1384 */ 1385 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1386 NULL); 1387 1388 /* Also tell the client, so that they release their reference. */ 1389 if (client->close_fn) { 1390 client->close_fn(client, negotiated); 1391 } 1392 } 1393 1394 static NBDRequestData *nbd_request_get(NBDClient *client) 1395 { 1396 NBDRequestData *req; 1397 1398 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1399 client->nb_requests++; 1400 1401 req = g_new0(NBDRequestData, 1); 1402 nbd_client_get(client); 1403 req->client = client; 1404 return req; 1405 } 1406 1407 static void nbd_request_put(NBDRequestData *req) 1408 { 1409 NBDClient *client = req->client; 1410 1411 if (req->data) { 1412 qemu_vfree(req->data); 1413 } 1414 g_free(req); 1415 1416 client->nb_requests--; 1417 nbd_client_receive_next_request(client); 1418 1419 nbd_client_put(client); 1420 } 1421 1422 static void blk_aio_attached(AioContext *ctx, void *opaque) 1423 { 1424 NBDExport *exp = opaque; 1425 NBDClient *client; 1426 1427 trace_nbd_blk_aio_attached(exp->name, ctx); 1428 1429 exp->ctx = ctx; 1430 1431 QTAILQ_FOREACH(client, &exp->clients, next) { 1432 qio_channel_attach_aio_context(client->ioc, ctx); 1433 if (client->recv_coroutine) { 1434 aio_co_schedule(ctx, client->recv_coroutine); 1435 } 1436 if (client->send_coroutine) { 1437 aio_co_schedule(ctx, client->send_coroutine); 1438 } 1439 } 1440 } 1441 1442 static void blk_aio_detach(void *opaque) 1443 { 1444 NBDExport *exp = opaque; 1445 NBDClient *client; 1446 1447 trace_nbd_blk_aio_detach(exp->name, exp->ctx); 1448 1449 QTAILQ_FOREACH(client, &exp->clients, next) { 1450 qio_channel_detach_aio_context(client->ioc); 1451 } 1452 1453 exp->ctx = NULL; 1454 } 1455 1456 static void nbd_eject_notifier(Notifier *n, void *data) 1457 { 1458 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1459 nbd_export_close(exp); 1460 } 1461 1462 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, 1463 uint64_t size, const char *name, const char *desc, 1464 const char *bitmap, bool readonly, bool shared, 1465 void (*close)(NBDExport *), bool writethrough, 1466 BlockBackend *on_eject_blk, Error **errp) 1467 { 1468 AioContext *ctx; 1469 BlockBackend *blk; 1470 NBDExport *exp = g_new0(NBDExport, 1); 1471 uint64_t perm; 1472 int ret; 1473 1474 /* 1475 * NBD exports are used for non-shared storage migration. Make sure 1476 * that BDRV_O_INACTIVE is cleared and the image is ready for write 1477 * access since the export could be available before migration handover. 1478 */ 1479 assert(name); 1480 ctx = bdrv_get_aio_context(bs); 1481 aio_context_acquire(ctx); 1482 bdrv_invalidate_cache(bs, NULL); 1483 aio_context_release(ctx); 1484 1485 /* Don't allow resize while the NBD server is running, otherwise we don't 1486 * care what happens with the node. */ 1487 perm = BLK_PERM_CONSISTENT_READ; 1488 if (!readonly) { 1489 perm |= BLK_PERM_WRITE; 1490 } 1491 blk = blk_new(bdrv_get_aio_context(bs), perm, 1492 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1493 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); 1494 ret = blk_insert_bs(blk, bs, errp); 1495 if (ret < 0) { 1496 goto fail; 1497 } 1498 blk_set_enable_write_cache(blk, !writethrough); 1499 blk_set_allow_aio_context_change(blk, true); 1500 1501 exp->refcount = 1; 1502 QTAILQ_INIT(&exp->clients); 1503 exp->blk = blk; 1504 assert(dev_offset <= INT64_MAX); 1505 exp->dev_offset = dev_offset; 1506 exp->name = g_strdup(name); 1507 exp->description = g_strdup(desc); 1508 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1509 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1510 if (readonly) { 1511 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1512 if (shared) { 1513 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1514 } 1515 } else { 1516 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1517 NBD_FLAG_SEND_FAST_ZERO); 1518 } 1519 assert(size <= INT64_MAX - dev_offset); 1520 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1521 1522 if (bitmap) { 1523 BdrvDirtyBitmap *bm = NULL; 1524 1525 while (true) { 1526 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1527 if (bm != NULL || bs->backing == NULL) { 1528 break; 1529 } 1530 1531 bs = bs->backing->bs; 1532 } 1533 1534 if (bm == NULL) { 1535 error_setg(errp, "Bitmap '%s' is not found", bitmap); 1536 goto fail; 1537 } 1538 1539 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1540 goto fail; 1541 } 1542 1543 if (readonly && bdrv_is_writable(bs) && 1544 bdrv_dirty_bitmap_enabled(bm)) { 1545 error_setg(errp, 1546 "Enabled bitmap '%s' incompatible with readonly export", 1547 bitmap); 1548 goto fail; 1549 } 1550 1551 bdrv_dirty_bitmap_set_busy(bm, true); 1552 exp->export_bitmap = bm; 1553 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1554 bitmap); 1555 } 1556 1557 exp->close = close; 1558 exp->ctx = blk_get_aio_context(blk); 1559 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1560 1561 if (on_eject_blk) { 1562 blk_ref(on_eject_blk); 1563 exp->eject_notifier_blk = on_eject_blk; 1564 exp->eject_notifier.notify = nbd_eject_notifier; 1565 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier); 1566 } 1567 QTAILQ_INSERT_TAIL(&exports, exp, next); 1568 nbd_export_get(exp); 1569 return exp; 1570 1571 fail: 1572 blk_unref(blk); 1573 g_free(exp->name); 1574 g_free(exp->description); 1575 g_free(exp); 1576 return NULL; 1577 } 1578 1579 NBDExport *nbd_export_find(const char *name) 1580 { 1581 NBDExport *exp; 1582 QTAILQ_FOREACH(exp, &exports, next) { 1583 if (strcmp(name, exp->name) == 0) { 1584 return exp; 1585 } 1586 } 1587 1588 return NULL; 1589 } 1590 1591 void nbd_export_close(NBDExport *exp) 1592 { 1593 NBDClient *client, *next; 1594 1595 nbd_export_get(exp); 1596 /* 1597 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1598 * close mode that stops advertising the export to new clients but 1599 * still permits existing clients to run to completion? Because of 1600 * that possibility, nbd_export_close() can be called more than 1601 * once on an export. 1602 */ 1603 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1604 client_close(client, true); 1605 } 1606 if (exp->name) { 1607 nbd_export_put(exp); 1608 g_free(exp->name); 1609 exp->name = NULL; 1610 QTAILQ_REMOVE(&exports, exp, next); 1611 } 1612 g_free(exp->description); 1613 exp->description = NULL; 1614 nbd_export_put(exp); 1615 } 1616 1617 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) 1618 { 1619 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { 1620 nbd_export_close(exp); 1621 return; 1622 } 1623 1624 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE); 1625 1626 error_setg(errp, "export '%s' still in use", exp->name); 1627 error_append_hint(errp, "Use mode='hard' to force client disconnect\n"); 1628 } 1629 1630 void nbd_export_get(NBDExport *exp) 1631 { 1632 assert(exp->refcount > 0); 1633 exp->refcount++; 1634 } 1635 1636 void nbd_export_put(NBDExport *exp) 1637 { 1638 assert(exp->refcount > 0); 1639 if (exp->refcount == 1) { 1640 nbd_export_close(exp); 1641 } 1642 1643 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen 1644 * if someone calls nbd_export_put() on named export not through 1645 * nbd_export_set_name() when refcount is 1. So, let's assert that 1646 * it is > 0. 1647 */ 1648 assert(exp->refcount > 0); 1649 if (--exp->refcount == 0) { 1650 assert(exp->name == NULL); 1651 assert(exp->description == NULL); 1652 1653 if (exp->close) { 1654 exp->close(exp); 1655 } 1656 1657 if (exp->blk) { 1658 if (exp->eject_notifier_blk) { 1659 notifier_remove(&exp->eject_notifier); 1660 blk_unref(exp->eject_notifier_blk); 1661 } 1662 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, 1663 blk_aio_detach, exp); 1664 blk_unref(exp->blk); 1665 exp->blk = NULL; 1666 } 1667 1668 if (exp->export_bitmap) { 1669 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); 1670 g_free(exp->export_bitmap_context); 1671 } 1672 1673 g_free(exp); 1674 } 1675 } 1676 1677 BlockBackend *nbd_export_get_blockdev(NBDExport *exp) 1678 { 1679 return exp->blk; 1680 } 1681 1682 void nbd_export_close_all(void) 1683 { 1684 NBDExport *exp, *next; 1685 1686 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { 1687 nbd_export_close(exp); 1688 } 1689 } 1690 1691 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1692 unsigned niov, Error **errp) 1693 { 1694 int ret; 1695 1696 g_assert(qemu_in_coroutine()); 1697 qemu_co_mutex_lock(&client->send_lock); 1698 client->send_coroutine = qemu_coroutine_self(); 1699 1700 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1701 1702 client->send_coroutine = NULL; 1703 qemu_co_mutex_unlock(&client->send_lock); 1704 1705 return ret; 1706 } 1707 1708 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1709 uint64_t handle) 1710 { 1711 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1712 stl_be_p(&reply->error, error); 1713 stq_be_p(&reply->handle, handle); 1714 } 1715 1716 static int nbd_co_send_simple_reply(NBDClient *client, 1717 uint64_t handle, 1718 uint32_t error, 1719 void *data, 1720 size_t len, 1721 Error **errp) 1722 { 1723 NBDSimpleReply reply; 1724 int nbd_err = system_errno_to_nbd_errno(error); 1725 struct iovec iov[] = { 1726 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1727 {.iov_base = data, .iov_len = len} 1728 }; 1729 1730 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1731 len); 1732 set_be_simple_reply(&reply, nbd_err, handle); 1733 1734 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1735 } 1736 1737 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1738 uint16_t type, uint64_t handle, uint32_t length) 1739 { 1740 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1741 stw_be_p(&chunk->flags, flags); 1742 stw_be_p(&chunk->type, type); 1743 stq_be_p(&chunk->handle, handle); 1744 stl_be_p(&chunk->length, length); 1745 } 1746 1747 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1748 uint64_t handle, 1749 Error **errp) 1750 { 1751 NBDStructuredReplyChunk chunk; 1752 struct iovec iov[] = { 1753 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1754 }; 1755 1756 trace_nbd_co_send_structured_done(handle); 1757 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1758 1759 return nbd_co_send_iov(client, iov, 1, errp); 1760 } 1761 1762 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1763 uint64_t handle, 1764 uint64_t offset, 1765 void *data, 1766 size_t size, 1767 bool final, 1768 Error **errp) 1769 { 1770 NBDStructuredReadData chunk; 1771 struct iovec iov[] = { 1772 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1773 {.iov_base = data, .iov_len = size} 1774 }; 1775 1776 assert(size); 1777 trace_nbd_co_send_structured_read(handle, offset, data, size); 1778 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1779 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1780 sizeof(chunk) - sizeof(chunk.h) + size); 1781 stq_be_p(&chunk.offset, offset); 1782 1783 return nbd_co_send_iov(client, iov, 2, errp); 1784 } 1785 1786 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1787 uint64_t handle, 1788 uint32_t error, 1789 const char *msg, 1790 Error **errp) 1791 { 1792 NBDStructuredError chunk; 1793 int nbd_err = system_errno_to_nbd_errno(error); 1794 struct iovec iov[] = { 1795 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1796 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1797 }; 1798 1799 assert(nbd_err); 1800 trace_nbd_co_send_structured_error(handle, nbd_err, 1801 nbd_err_lookup(nbd_err), msg ? msg : ""); 1802 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1803 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1804 stl_be_p(&chunk.error, nbd_err); 1805 stw_be_p(&chunk.message_length, iov[1].iov_len); 1806 1807 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1808 } 1809 1810 /* Do a sparse read and send the structured reply to the client. 1811 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1812 * reported to the client, at which point this function succeeds. 1813 */ 1814 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1815 uint64_t handle, 1816 uint64_t offset, 1817 uint8_t *data, 1818 size_t size, 1819 Error **errp) 1820 { 1821 int ret = 0; 1822 NBDExport *exp = client->exp; 1823 size_t progress = 0; 1824 1825 while (progress < size) { 1826 int64_t pnum; 1827 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL, 1828 offset + progress, 1829 size - progress, &pnum, NULL, 1830 NULL); 1831 bool final; 1832 1833 if (status < 0) { 1834 char *msg = g_strdup_printf("unable to check for holes: %s", 1835 strerror(-status)); 1836 1837 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1838 errp); 1839 g_free(msg); 1840 return ret; 1841 } 1842 assert(pnum && pnum <= size - progress); 1843 final = progress + pnum == size; 1844 if (status & BDRV_BLOCK_ZERO) { 1845 NBDStructuredReadHole chunk; 1846 struct iovec iov[] = { 1847 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1848 }; 1849 1850 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1851 pnum); 1852 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1853 NBD_REPLY_TYPE_OFFSET_HOLE, 1854 handle, sizeof(chunk) - sizeof(chunk.h)); 1855 stq_be_p(&chunk.offset, offset + progress); 1856 stl_be_p(&chunk.length, pnum); 1857 ret = nbd_co_send_iov(client, iov, 1, errp); 1858 } else { 1859 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, 1860 data + progress, pnum); 1861 if (ret < 0) { 1862 error_setg_errno(errp, -ret, "reading from file failed"); 1863 break; 1864 } 1865 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1866 data + progress, pnum, final, 1867 errp); 1868 } 1869 1870 if (ret < 0) { 1871 break; 1872 } 1873 progress += pnum; 1874 } 1875 return ret; 1876 } 1877 1878 /* 1879 * Populate @extents from block status. Update @bytes to be the actual 1880 * length encoded (which may be smaller than the original), and update 1881 * @nb_extents to the number of extents used. 1882 * 1883 * Returns zero on success and -errno on bdrv_block_status_above failure. 1884 */ 1885 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1886 uint64_t *bytes, NBDExtent *extents, 1887 unsigned int *nb_extents) 1888 { 1889 uint64_t remaining_bytes = *bytes; 1890 NBDExtent *extent = extents, *extents_end = extents + *nb_extents; 1891 bool first_extent = true; 1892 1893 assert(*nb_extents); 1894 while (remaining_bytes) { 1895 uint32_t flags; 1896 int64_t num; 1897 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes, 1898 &num, NULL, NULL); 1899 1900 if (ret < 0) { 1901 return ret; 1902 } 1903 1904 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1905 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1906 1907 if (first_extent) { 1908 extent->flags = flags; 1909 extent->length = num; 1910 first_extent = false; 1911 } else if (flags == extent->flags) { 1912 /* extend current extent */ 1913 extent->length += num; 1914 } else { 1915 if (extent + 1 == extents_end) { 1916 break; 1917 } 1918 1919 /* start new extent */ 1920 extent++; 1921 extent->flags = flags; 1922 extent->length = num; 1923 } 1924 offset += num; 1925 remaining_bytes -= num; 1926 } 1927 1928 extents_end = extent + 1; 1929 1930 for (extent = extents; extent < extents_end; extent++) { 1931 extent->flags = cpu_to_be32(extent->flags); 1932 extent->length = cpu_to_be32(extent->length); 1933 } 1934 1935 *bytes -= remaining_bytes; 1936 *nb_extents = extents_end - extents; 1937 1938 return 0; 1939 } 1940 1941 /* nbd_co_send_extents 1942 * 1943 * @length is only for tracing purposes (and may be smaller or larger 1944 * than the client's original request). @last controls whether 1945 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in 1946 * big-endian format. 1947 */ 1948 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1949 NBDExtent *extents, unsigned int nb_extents, 1950 uint64_t length, bool last, 1951 uint32_t context_id, Error **errp) 1952 { 1953 NBDStructuredMeta chunk; 1954 1955 struct iovec iov[] = { 1956 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1957 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])} 1958 }; 1959 1960 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last); 1961 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1962 NBD_REPLY_TYPE_BLOCK_STATUS, 1963 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1964 stl_be_p(&chunk.context_id, context_id); 1965 1966 return nbd_co_send_iov(client, iov, 2, errp); 1967 } 1968 1969 /* Get block status from the exported device and send it to the client */ 1970 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1971 BlockDriverState *bs, uint64_t offset, 1972 uint32_t length, bool dont_fragment, 1973 bool last, uint32_t context_id, 1974 Error **errp) 1975 { 1976 int ret; 1977 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 1978 NBDExtent *extents = g_new(NBDExtent, nb_extents); 1979 uint64_t final_length = length; 1980 1981 ret = blockstatus_to_extents(bs, offset, &final_length, extents, 1982 &nb_extents); 1983 if (ret < 0) { 1984 g_free(extents); 1985 return nbd_co_send_structured_error( 1986 client, handle, -ret, "can't get block status", errp); 1987 } 1988 1989 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 1990 final_length, last, context_id, errp); 1991 1992 g_free(extents); 1993 1994 return ret; 1995 } 1996 1997 /* 1998 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the 1999 * final extent may exceed the original @length. Store in @length the 2000 * byte length encoded (which may be smaller or larger than the 2001 * original), and return the number of extents used. 2002 */ 2003 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset, 2004 uint64_t *length, NBDExtent *extents, 2005 unsigned int nb_extents, 2006 bool dont_fragment) 2007 { 2008 uint64_t begin = offset, end = offset; 2009 uint64_t overall_end = offset + *length; 2010 unsigned int i = 0; 2011 BdrvDirtyBitmapIter *it; 2012 bool dirty; 2013 2014 bdrv_dirty_bitmap_lock(bitmap); 2015 2016 it = bdrv_dirty_iter_new(bitmap); 2017 dirty = bdrv_dirty_bitmap_get_locked(bitmap, offset); 2018 2019 assert(begin < overall_end && nb_extents); 2020 while (begin < overall_end && i < nb_extents) { 2021 bool next_dirty = !dirty; 2022 2023 if (dirty) { 2024 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX); 2025 } else { 2026 bdrv_set_dirty_iter(it, begin); 2027 end = bdrv_dirty_iter_next(it); 2028 } 2029 if (end == -1 || end - begin > UINT32_MAX) { 2030 /* Cap to an aligned value < 4G beyond begin. */ 2031 end = MIN(bdrv_dirty_bitmap_size(bitmap), 2032 begin + UINT32_MAX + 1 - 2033 bdrv_dirty_bitmap_granularity(bitmap)); 2034 next_dirty = dirty; 2035 } 2036 if (dont_fragment && end > overall_end) { 2037 end = overall_end; 2038 } 2039 2040 extents[i].length = cpu_to_be32(end - begin); 2041 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0); 2042 i++; 2043 begin = end; 2044 dirty = next_dirty; 2045 } 2046 2047 bdrv_dirty_iter_free(it); 2048 2049 bdrv_dirty_bitmap_unlock(bitmap); 2050 2051 assert(offset < end); 2052 *length = end - offset; 2053 return i; 2054 } 2055 2056 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2057 BdrvDirtyBitmap *bitmap, uint64_t offset, 2058 uint32_t length, bool dont_fragment, bool last, 2059 uint32_t context_id, Error **errp) 2060 { 2061 int ret; 2062 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2063 NBDExtent *extents = g_new(NBDExtent, nb_extents); 2064 uint64_t final_length = length; 2065 2066 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents, 2067 nb_extents, dont_fragment); 2068 2069 ret = nbd_co_send_extents(client, handle, extents, nb_extents, 2070 final_length, last, context_id, errp); 2071 2072 g_free(extents); 2073 2074 return ret; 2075 } 2076 2077 /* nbd_co_receive_request 2078 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2079 * connection right away, and any other negative value to report an error to 2080 * the client (although the caller may still need to disconnect after reporting 2081 * the error). 2082 */ 2083 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2084 Error **errp) 2085 { 2086 NBDClient *client = req->client; 2087 int valid_flags; 2088 2089 g_assert(qemu_in_coroutine()); 2090 assert(client->recv_coroutine == qemu_coroutine_self()); 2091 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2092 return -EIO; 2093 } 2094 2095 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2096 nbd_cmd_lookup(request->type)); 2097 2098 if (request->type != NBD_CMD_WRITE) { 2099 /* No payload, we are ready to read the next request. */ 2100 req->complete = true; 2101 } 2102 2103 if (request->type == NBD_CMD_DISC) { 2104 /* Special case: we're going to disconnect without a reply, 2105 * whether or not flags, from, or len are bogus */ 2106 return -EIO; 2107 } 2108 2109 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2110 request->type == NBD_CMD_CACHE) 2111 { 2112 if (request->len > NBD_MAX_BUFFER_SIZE) { 2113 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2114 request->len, NBD_MAX_BUFFER_SIZE); 2115 return -EINVAL; 2116 } 2117 2118 if (request->type != NBD_CMD_CACHE) { 2119 req->data = blk_try_blockalign(client->exp->blk, request->len); 2120 if (req->data == NULL) { 2121 error_setg(errp, "No memory"); 2122 return -ENOMEM; 2123 } 2124 } 2125 } 2126 2127 if (request->type == NBD_CMD_WRITE) { 2128 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2129 errp) < 0) 2130 { 2131 return -EIO; 2132 } 2133 req->complete = true; 2134 2135 trace_nbd_co_receive_request_payload_received(request->handle, 2136 request->len); 2137 } 2138 2139 /* Sanity checks. */ 2140 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2141 (request->type == NBD_CMD_WRITE || 2142 request->type == NBD_CMD_WRITE_ZEROES || 2143 request->type == NBD_CMD_TRIM)) { 2144 error_setg(errp, "Export is read-only"); 2145 return -EROFS; 2146 } 2147 if (request->from > client->exp->size || 2148 request->len > client->exp->size - request->from) { 2149 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2150 ", Size: %" PRIu64, request->from, request->len, 2151 client->exp->size); 2152 return (request->type == NBD_CMD_WRITE || 2153 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2154 } 2155 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2156 client->check_align)) { 2157 /* 2158 * The block layer gracefully handles unaligned requests, but 2159 * it's still worth tracing client non-compliance 2160 */ 2161 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2162 request->from, 2163 request->len, 2164 client->check_align); 2165 } 2166 valid_flags = NBD_CMD_FLAG_FUA; 2167 if (request->type == NBD_CMD_READ && client->structured_reply) { 2168 valid_flags |= NBD_CMD_FLAG_DF; 2169 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2170 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2171 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2172 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2173 } 2174 if (request->flags & ~valid_flags) { 2175 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2176 nbd_cmd_lookup(request->type), request->flags); 2177 return -EINVAL; 2178 } 2179 2180 return 0; 2181 } 2182 2183 /* Send simple reply without a payload, or a structured error 2184 * @error_msg is ignored if @ret >= 0 2185 * Returns 0 if connection is still live, -errno on failure to talk to client 2186 */ 2187 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2188 uint64_t handle, 2189 int ret, 2190 const char *error_msg, 2191 Error **errp) 2192 { 2193 if (client->structured_reply && ret < 0) { 2194 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2195 errp); 2196 } else { 2197 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2198 NULL, 0, errp); 2199 } 2200 } 2201 2202 /* Handle NBD_CMD_READ request. 2203 * Return -errno if sending fails. Other errors are reported directly to the 2204 * client as an error reply. */ 2205 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2206 uint8_t *data, Error **errp) 2207 { 2208 int ret; 2209 NBDExport *exp = client->exp; 2210 2211 assert(request->type == NBD_CMD_READ); 2212 2213 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2214 if (request->flags & NBD_CMD_FLAG_FUA) { 2215 ret = blk_co_flush(exp->blk); 2216 if (ret < 0) { 2217 return nbd_send_generic_reply(client, request->handle, ret, 2218 "flush failed", errp); 2219 } 2220 } 2221 2222 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2223 request->len) 2224 { 2225 return nbd_co_send_sparse_read(client, request->handle, request->from, 2226 data, request->len, errp); 2227 } 2228 2229 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, 2230 request->len); 2231 if (ret < 0) { 2232 return nbd_send_generic_reply(client, request->handle, ret, 2233 "reading from file failed", errp); 2234 } 2235 2236 if (client->structured_reply) { 2237 if (request->len) { 2238 return nbd_co_send_structured_read(client, request->handle, 2239 request->from, data, 2240 request->len, true, errp); 2241 } else { 2242 return nbd_co_send_structured_done(client, request->handle, errp); 2243 } 2244 } else { 2245 return nbd_co_send_simple_reply(client, request->handle, 0, 2246 data, request->len, errp); 2247 } 2248 } 2249 2250 /* 2251 * nbd_do_cmd_cache 2252 * 2253 * Handle NBD_CMD_CACHE request. 2254 * Return -errno if sending fails. Other errors are reported directly to the 2255 * client as an error reply. 2256 */ 2257 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2258 Error **errp) 2259 { 2260 int ret; 2261 NBDExport *exp = client->exp; 2262 2263 assert(request->type == NBD_CMD_CACHE); 2264 2265 ret = blk_co_preadv(exp->blk, request->from + exp->dev_offset, request->len, 2266 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2267 2268 return nbd_send_generic_reply(client, request->handle, ret, 2269 "caching data failed", errp); 2270 } 2271 2272 /* Handle NBD request. 2273 * Return -errno if sending fails. Other errors are reported directly to the 2274 * client as an error reply. */ 2275 static coroutine_fn int nbd_handle_request(NBDClient *client, 2276 NBDRequest *request, 2277 uint8_t *data, Error **errp) 2278 { 2279 int ret; 2280 int flags; 2281 NBDExport *exp = client->exp; 2282 char *msg; 2283 2284 switch (request->type) { 2285 case NBD_CMD_CACHE: 2286 return nbd_do_cmd_cache(client, request, errp); 2287 2288 case NBD_CMD_READ: 2289 return nbd_do_cmd_read(client, request, data, errp); 2290 2291 case NBD_CMD_WRITE: 2292 flags = 0; 2293 if (request->flags & NBD_CMD_FLAG_FUA) { 2294 flags |= BDRV_REQ_FUA; 2295 } 2296 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, 2297 data, request->len, flags); 2298 return nbd_send_generic_reply(client, request->handle, ret, 2299 "writing to file failed", errp); 2300 2301 case NBD_CMD_WRITE_ZEROES: 2302 flags = 0; 2303 if (request->flags & NBD_CMD_FLAG_FUA) { 2304 flags |= BDRV_REQ_FUA; 2305 } 2306 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2307 flags |= BDRV_REQ_MAY_UNMAP; 2308 } 2309 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2310 flags |= BDRV_REQ_NO_FALLBACK; 2311 } 2312 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, 2313 request->len, flags); 2314 return nbd_send_generic_reply(client, request->handle, ret, 2315 "writing to file failed", errp); 2316 2317 case NBD_CMD_DISC: 2318 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2319 abort(); 2320 2321 case NBD_CMD_FLUSH: 2322 ret = blk_co_flush(exp->blk); 2323 return nbd_send_generic_reply(client, request->handle, ret, 2324 "flush failed", errp); 2325 2326 case NBD_CMD_TRIM: 2327 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, 2328 request->len); 2329 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { 2330 ret = blk_co_flush(exp->blk); 2331 } 2332 return nbd_send_generic_reply(client, request->handle, ret, 2333 "discard failed", errp); 2334 2335 case NBD_CMD_BLOCK_STATUS: 2336 if (!request->len) { 2337 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2338 "need non-zero length", errp); 2339 } 2340 if (client->export_meta.valid && 2341 (client->export_meta.base_allocation || 2342 client->export_meta.bitmap)) 2343 { 2344 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2345 2346 if (client->export_meta.base_allocation) { 2347 ret = nbd_co_send_block_status(client, request->handle, 2348 blk_bs(exp->blk), request->from, 2349 request->len, dont_fragment, 2350 !client->export_meta.bitmap, 2351 NBD_META_ID_BASE_ALLOCATION, 2352 errp); 2353 if (ret < 0) { 2354 return ret; 2355 } 2356 } 2357 2358 if (client->export_meta.bitmap) { 2359 ret = nbd_co_send_bitmap(client, request->handle, 2360 client->exp->export_bitmap, 2361 request->from, request->len, 2362 dont_fragment, 2363 true, NBD_META_ID_DIRTY_BITMAP, errp); 2364 if (ret < 0) { 2365 return ret; 2366 } 2367 } 2368 2369 return ret; 2370 } else { 2371 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2372 "CMD_BLOCK_STATUS not negotiated", 2373 errp); 2374 } 2375 2376 default: 2377 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2378 request->type); 2379 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2380 errp); 2381 g_free(msg); 2382 return ret; 2383 } 2384 } 2385 2386 /* Owns a reference to the NBDClient passed as opaque. */ 2387 static coroutine_fn void nbd_trip(void *opaque) 2388 { 2389 NBDClient *client = opaque; 2390 NBDRequestData *req; 2391 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2392 int ret; 2393 Error *local_err = NULL; 2394 2395 trace_nbd_trip(); 2396 if (client->closing) { 2397 nbd_client_put(client); 2398 return; 2399 } 2400 2401 req = nbd_request_get(client); 2402 ret = nbd_co_receive_request(req, &request, &local_err); 2403 client->recv_coroutine = NULL; 2404 2405 if (client->closing) { 2406 /* 2407 * The client may be closed when we are blocked in 2408 * nbd_co_receive_request() 2409 */ 2410 goto done; 2411 } 2412 2413 nbd_client_receive_next_request(client); 2414 if (ret == -EIO) { 2415 goto disconnect; 2416 } 2417 2418 if (ret < 0) { 2419 /* It wans't -EIO, so, according to nbd_co_receive_request() 2420 * semantics, we should return the error to the client. */ 2421 Error *export_err = local_err; 2422 2423 local_err = NULL; 2424 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2425 error_get_pretty(export_err), &local_err); 2426 error_free(export_err); 2427 } else { 2428 ret = nbd_handle_request(client, &request, req->data, &local_err); 2429 } 2430 if (ret < 0) { 2431 error_prepend(&local_err, "Failed to send reply: "); 2432 goto disconnect; 2433 } 2434 2435 /* We must disconnect after NBD_CMD_WRITE if we did not 2436 * read the payload. 2437 */ 2438 if (!req->complete) { 2439 error_setg(&local_err, "Request handling failed in intermediate state"); 2440 goto disconnect; 2441 } 2442 2443 done: 2444 nbd_request_put(req); 2445 nbd_client_put(client); 2446 return; 2447 2448 disconnect: 2449 if (local_err) { 2450 error_reportf_err(local_err, "Disconnect client, due to: "); 2451 } 2452 nbd_request_put(req); 2453 client_close(client, true); 2454 nbd_client_put(client); 2455 } 2456 2457 static void nbd_client_receive_next_request(NBDClient *client) 2458 { 2459 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2460 nbd_client_get(client); 2461 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2462 aio_co_schedule(client->exp->ctx, client->recv_coroutine); 2463 } 2464 } 2465 2466 static coroutine_fn void nbd_co_client_start(void *opaque) 2467 { 2468 NBDClient *client = opaque; 2469 Error *local_err = NULL; 2470 2471 qemu_co_mutex_init(&client->send_lock); 2472 2473 if (nbd_negotiate(client, &local_err)) { 2474 if (local_err) { 2475 error_report_err(local_err); 2476 } 2477 client_close(client, false); 2478 return; 2479 } 2480 2481 nbd_client_receive_next_request(client); 2482 } 2483 2484 /* 2485 * Create a new client listener using the given channel @sioc. 2486 * Begin servicing it in a coroutine. When the connection closes, call 2487 * @close_fn with an indication of whether the client completed negotiation. 2488 */ 2489 void nbd_client_new(QIOChannelSocket *sioc, 2490 QCryptoTLSCreds *tlscreds, 2491 const char *tlsauthz, 2492 void (*close_fn)(NBDClient *, bool)) 2493 { 2494 NBDClient *client; 2495 Coroutine *co; 2496 2497 client = g_new0(NBDClient, 1); 2498 client->refcount = 1; 2499 client->tlscreds = tlscreds; 2500 if (tlscreds) { 2501 object_ref(OBJECT(client->tlscreds)); 2502 } 2503 client->tlsauthz = g_strdup(tlsauthz); 2504 client->sioc = sioc; 2505 object_ref(OBJECT(client->sioc)); 2506 client->ioc = QIO_CHANNEL(sioc); 2507 object_ref(OBJECT(client->ioc)); 2508 client->close_fn = close_fn; 2509 2510 co = qemu_coroutine_create(nbd_co_client_start, client); 2511 qemu_coroutine_enter(co); 2512 } 2513