1 /* 2 * Copyright (C) 2016-2020 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 22 #include "block/export.h" 23 #include "qapi/error.h" 24 #include "qemu/queue.h" 25 #include "trace.h" 26 #include "nbd-internal.h" 27 #include "qemu/units.h" 28 29 #define NBD_META_ID_BASE_ALLOCATION 0 30 #define NBD_META_ID_ALLOCATION_DEPTH 1 31 /* Dirty bitmaps use 'NBD_META_ID_DIRTY_BITMAP + i', so keep this id last. */ 32 #define NBD_META_ID_DIRTY_BITMAP 2 33 34 /* 35 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical 36 * constant. If an increase is needed, note that the NBD protocol 37 * recommends no larger than 32 mb, so that the client won't consider 38 * the reply as a denial of service attack. 39 */ 40 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) 41 42 static int system_errno_to_nbd_errno(int err) 43 { 44 switch (err) { 45 case 0: 46 return NBD_SUCCESS; 47 case EPERM: 48 case EROFS: 49 return NBD_EPERM; 50 case EIO: 51 return NBD_EIO; 52 case ENOMEM: 53 return NBD_ENOMEM; 54 #ifdef EDQUOT 55 case EDQUOT: 56 #endif 57 case EFBIG: 58 case ENOSPC: 59 return NBD_ENOSPC; 60 case EOVERFLOW: 61 return NBD_EOVERFLOW; 62 case ENOTSUP: 63 #if ENOTSUP != EOPNOTSUPP 64 case EOPNOTSUPP: 65 #endif 66 return NBD_ENOTSUP; 67 case ESHUTDOWN: 68 return NBD_ESHUTDOWN; 69 case EINVAL: 70 default: 71 return NBD_EINVAL; 72 } 73 } 74 75 /* Definitions for opaque data types */ 76 77 typedef struct NBDRequestData NBDRequestData; 78 79 struct NBDRequestData { 80 QSIMPLEQ_ENTRY(NBDRequestData) entry; 81 NBDClient *client; 82 uint8_t *data; 83 bool complete; 84 }; 85 86 struct NBDExport { 87 BlockExport common; 88 89 char *name; 90 char *description; 91 uint64_t size; 92 uint16_t nbdflags; 93 QTAILQ_HEAD(, NBDClient) clients; 94 QTAILQ_ENTRY(NBDExport) next; 95 96 BlockBackend *eject_notifier_blk; 97 Notifier eject_notifier; 98 99 bool allocation_depth; 100 BdrvDirtyBitmap **export_bitmaps; 101 size_t nr_export_bitmaps; 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 size_t count; /* number of negotiated contexts */ 112 bool base_allocation; /* export base:allocation context (block status) */ 113 bool allocation_depth; /* export qemu:allocation-depth */ 114 bool *bitmaps; /* 115 * export qemu:dirty-bitmap:<export bitmap name>, 116 * sized by exp->nr_export_bitmaps 117 */ 118 } NBDExportMetaContexts; 119 120 struct NBDClient { 121 int refcount; 122 void (*close_fn)(NBDClient *client, bool negotiated); 123 124 NBDExport *exp; 125 QCryptoTLSCreds *tlscreds; 126 char *tlsauthz; 127 QIOChannelSocket *sioc; /* The underlying data channel */ 128 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 129 130 Coroutine *recv_coroutine; 131 132 CoMutex send_lock; 133 Coroutine *send_coroutine; 134 135 bool read_yielding; 136 bool quiescing; 137 138 QTAILQ_ENTRY(NBDClient) next; 139 int nb_requests; 140 bool closing; 141 142 uint32_t check_align; /* If non-zero, check for aligned client requests */ 143 144 bool structured_reply; 145 NBDExportMetaContexts export_meta; 146 147 uint32_t opt; /* Current option being negotiated */ 148 uint32_t optlen; /* remaining length of data in ioc for the option being 149 negotiated now */ 150 }; 151 152 static void nbd_client_receive_next_request(NBDClient *client); 153 154 /* Basic flow for negotiation 155 156 Server Client 157 Negotiate 158 159 or 160 161 Server Client 162 Negotiate #1 163 Option 164 Negotiate #2 165 166 ---- 167 168 followed by 169 170 Server Client 171 Request 172 Response 173 Request 174 Response 175 ... 176 ... 177 Request (type == 2) 178 179 */ 180 181 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 182 uint32_t type, uint32_t length) 183 { 184 stq_be_p(&rep->magic, NBD_REP_MAGIC); 185 stl_be_p(&rep->option, option); 186 stl_be_p(&rep->type, type); 187 stl_be_p(&rep->length, length); 188 } 189 190 /* Send a reply header, including length, but no payload. 191 * Return -errno on error, 0 on success. */ 192 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 193 uint32_t len, Error **errp) 194 { 195 NBDOptionReply rep; 196 197 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 198 type, nbd_rep_lookup(type), len); 199 200 assert(len < NBD_MAX_BUFFER_SIZE); 201 202 set_be_option_rep(&rep, client->opt, type, len); 203 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 204 } 205 206 /* Send a reply header with default 0 length. 207 * Return -errno on error, 0 on success. */ 208 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 209 Error **errp) 210 { 211 return nbd_negotiate_send_rep_len(client, type, 0, errp); 212 } 213 214 /* Send an error reply. 215 * Return -errno on error, 0 on success. */ 216 static int GCC_FMT_ATTR(4, 0) 217 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 218 Error **errp, const char *fmt, va_list va) 219 { 220 ERRP_GUARD(); 221 g_autofree char *msg = NULL; 222 int ret; 223 size_t len; 224 225 msg = g_strdup_vprintf(fmt, va); 226 len = strlen(msg); 227 assert(len < NBD_MAX_STRING_SIZE); 228 trace_nbd_negotiate_send_rep_err(msg); 229 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 230 if (ret < 0) { 231 return ret; 232 } 233 if (nbd_write(client->ioc, msg, len, errp) < 0) { 234 error_prepend(errp, "write failed (error message): "); 235 return -EIO; 236 } 237 238 return 0; 239 } 240 241 /* 242 * Return a malloc'd copy of @name suitable for use in an error reply. 243 */ 244 static char * 245 nbd_sanitize_name(const char *name) 246 { 247 if (strnlen(name, 80) < 80) { 248 return g_strdup(name); 249 } 250 /* XXX Should we also try to sanitize any control characters? */ 251 return g_strdup_printf("%.80s...", name); 252 } 253 254 /* Send an error reply. 255 * Return -errno on error, 0 on success. */ 256 static int GCC_FMT_ATTR(4, 5) 257 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 258 Error **errp, const char *fmt, ...) 259 { 260 va_list va; 261 int ret; 262 263 va_start(va, fmt); 264 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 265 va_end(va); 266 return ret; 267 } 268 269 /* Drop remainder of the current option, and send a reply with the 270 * given error type and message. Return -errno on read or write 271 * failure; or 0 if connection is still live. */ 272 static int GCC_FMT_ATTR(4, 0) 273 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 274 const char *fmt, va_list va) 275 { 276 int ret = nbd_drop(client->ioc, client->optlen, errp); 277 278 client->optlen = 0; 279 if (!ret) { 280 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 281 } 282 return ret; 283 } 284 285 static int GCC_FMT_ATTR(4, 5) 286 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 287 const char *fmt, ...) 288 { 289 int ret; 290 va_list va; 291 292 va_start(va, fmt); 293 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 294 va_end(va); 295 296 return ret; 297 } 298 299 static int GCC_FMT_ATTR(3, 4) 300 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 301 { 302 int ret; 303 va_list va; 304 305 va_start(va, fmt); 306 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 307 va_end(va); 308 309 return ret; 310 } 311 312 /* Read size bytes from the unparsed payload of the current option. 313 * If @check_nul, require that no NUL bytes appear in buffer. 314 * Return -errno on I/O error, 0 if option was completely handled by 315 * sending a reply about inconsistent lengths, or 1 on success. */ 316 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 317 bool check_nul, Error **errp) 318 { 319 if (size > client->optlen) { 320 return nbd_opt_invalid(client, errp, 321 "Inconsistent lengths in option %s", 322 nbd_opt_lookup(client->opt)); 323 } 324 client->optlen -= size; 325 if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) { 326 return -EIO; 327 } 328 329 if (check_nul && strnlen(buffer, size) != size) { 330 return nbd_opt_invalid(client, errp, 331 "Unexpected embedded NUL in option %s", 332 nbd_opt_lookup(client->opt)); 333 } 334 return 1; 335 } 336 337 /* Drop size bytes from the unparsed payload of the current option. 338 * Return -errno on I/O error, 0 if option was completely handled by 339 * sending a reply about inconsistent lengths, or 1 on success. */ 340 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 341 { 342 if (size > client->optlen) { 343 return nbd_opt_invalid(client, errp, 344 "Inconsistent lengths in option %s", 345 nbd_opt_lookup(client->opt)); 346 } 347 client->optlen -= size; 348 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 349 } 350 351 /* nbd_opt_read_name 352 * 353 * Read a string with the format: 354 * uint32_t len (<= NBD_MAX_STRING_SIZE) 355 * len bytes string (not 0-terminated) 356 * 357 * On success, @name will be allocated. 358 * If @length is non-null, it will be set to the actual string length. 359 * 360 * Return -errno on I/O error, 0 if option was completely handled by 361 * sending a reply about inconsistent lengths, or 1 on success. 362 */ 363 static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length, 364 Error **errp) 365 { 366 int ret; 367 uint32_t len; 368 g_autofree char *local_name = NULL; 369 370 *name = NULL; 371 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 372 if (ret <= 0) { 373 return ret; 374 } 375 len = cpu_to_be32(len); 376 377 if (len > NBD_MAX_STRING_SIZE) { 378 return nbd_opt_invalid(client, errp, 379 "Invalid name length: %" PRIu32, len); 380 } 381 382 local_name = g_malloc(len + 1); 383 ret = nbd_opt_read(client, local_name, len, true, errp); 384 if (ret <= 0) { 385 return ret; 386 } 387 local_name[len] = '\0'; 388 389 if (length) { 390 *length = len; 391 } 392 *name = g_steal_pointer(&local_name); 393 394 return 1; 395 } 396 397 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 398 * Return -errno on error, 0 on success. */ 399 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 400 Error **errp) 401 { 402 ERRP_GUARD(); 403 size_t name_len, desc_len; 404 uint32_t len; 405 const char *name = exp->name ? exp->name : ""; 406 const char *desc = exp->description ? exp->description : ""; 407 QIOChannel *ioc = client->ioc; 408 int ret; 409 410 trace_nbd_negotiate_send_rep_list(name, desc); 411 name_len = strlen(name); 412 desc_len = strlen(desc); 413 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE); 414 len = name_len + desc_len + sizeof(len); 415 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 416 if (ret < 0) { 417 return ret; 418 } 419 420 len = cpu_to_be32(name_len); 421 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 422 error_prepend(errp, "write failed (name length): "); 423 return -EINVAL; 424 } 425 426 if (nbd_write(ioc, name, name_len, errp) < 0) { 427 error_prepend(errp, "write failed (name buffer): "); 428 return -EINVAL; 429 } 430 431 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 432 error_prepend(errp, "write failed (description buffer): "); 433 return -EINVAL; 434 } 435 436 return 0; 437 } 438 439 /* Process the NBD_OPT_LIST command, with a potential series of replies. 440 * Return -errno on error, 0 on success. */ 441 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 442 { 443 NBDExport *exp; 444 assert(client->opt == NBD_OPT_LIST); 445 446 /* For each export, send a NBD_REP_SERVER reply. */ 447 QTAILQ_FOREACH(exp, &exports, next) { 448 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 449 return -EINVAL; 450 } 451 } 452 /* Finish with a NBD_REP_ACK. */ 453 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 454 } 455 456 static void nbd_check_meta_export(NBDClient *client) 457 { 458 if (client->exp != client->export_meta.exp) { 459 client->export_meta.count = 0; 460 } 461 } 462 463 /* Send a reply to NBD_OPT_EXPORT_NAME. 464 * Return -errno on error, 0 on success. */ 465 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, 466 Error **errp) 467 { 468 ERRP_GUARD(); 469 g_autofree char *name = NULL; 470 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 471 size_t len; 472 int ret; 473 uint16_t myflags; 474 475 /* Client sends: 476 [20 .. xx] export name (length bytes) 477 Server replies: 478 [ 0 .. 7] size 479 [ 8 .. 9] export flags 480 [10 .. 133] reserved (0) [unless no_zeroes] 481 */ 482 trace_nbd_negotiate_handle_export_name(); 483 if (client->optlen > NBD_MAX_STRING_SIZE) { 484 error_setg(errp, "Bad length received"); 485 return -EINVAL; 486 } 487 name = g_malloc(client->optlen + 1); 488 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 489 return -EIO; 490 } 491 name[client->optlen] = '\0'; 492 client->optlen = 0; 493 494 trace_nbd_negotiate_handle_export_name_request(name); 495 496 client->exp = nbd_export_find(name); 497 if (!client->exp) { 498 error_setg(errp, "export not found"); 499 return -EINVAL; 500 } 501 502 myflags = client->exp->nbdflags; 503 if (client->structured_reply) { 504 myflags |= NBD_FLAG_SEND_DF; 505 } 506 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags); 507 stq_be_p(buf, client->exp->size); 508 stw_be_p(buf + 8, myflags); 509 len = no_zeroes ? 10 : sizeof(buf); 510 ret = nbd_write(client->ioc, buf, len, errp); 511 if (ret < 0) { 512 error_prepend(errp, "write failed: "); 513 return ret; 514 } 515 516 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 517 blk_exp_ref(&client->exp->common); 518 nbd_check_meta_export(client); 519 520 return 0; 521 } 522 523 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 524 * The buffer does NOT include the info type prefix. 525 * Return -errno on error, 0 if ready to send more. */ 526 static int nbd_negotiate_send_info(NBDClient *client, 527 uint16_t info, uint32_t length, void *buf, 528 Error **errp) 529 { 530 int rc; 531 532 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 533 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 534 sizeof(info) + length, errp); 535 if (rc < 0) { 536 return rc; 537 } 538 info = cpu_to_be16(info); 539 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 540 return -EIO; 541 } 542 if (nbd_write(client->ioc, buf, length, errp) < 0) { 543 return -EIO; 544 } 545 return 0; 546 } 547 548 /* nbd_reject_length: Handle any unexpected payload. 549 * @fatal requests that we quit talking to the client, even if we are able 550 * to successfully send an error reply. 551 * Return: 552 * -errno transmission error occurred or @fatal was requested, errp is set 553 * 0 error message successfully sent to client, errp is not set 554 */ 555 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 556 { 557 int ret; 558 559 assert(client->optlen); 560 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 561 nbd_opt_lookup(client->opt)); 562 if (fatal && !ret) { 563 error_setg(errp, "option '%s' has unexpected length", 564 nbd_opt_lookup(client->opt)); 565 return -EINVAL; 566 } 567 return ret; 568 } 569 570 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 571 * Return -errno on error, 0 if ready for next option, and 1 to move 572 * into transmission phase. */ 573 static int nbd_negotiate_handle_info(NBDClient *client, Error **errp) 574 { 575 int rc; 576 g_autofree char *name = NULL; 577 NBDExport *exp; 578 uint16_t requests; 579 uint16_t request; 580 uint32_t namelen = 0; 581 bool sendname = false; 582 bool blocksize = false; 583 uint32_t sizes[3]; 584 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 585 uint32_t check_align = 0; 586 uint16_t myflags; 587 588 /* Client sends: 589 4 bytes: L, name length (can be 0) 590 L bytes: export name 591 2 bytes: N, number of requests (can be 0) 592 N * 2 bytes: N requests 593 */ 594 rc = nbd_opt_read_name(client, &name, &namelen, errp); 595 if (rc <= 0) { 596 return rc; 597 } 598 trace_nbd_negotiate_handle_export_name_request(name); 599 600 rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp); 601 if (rc <= 0) { 602 return rc; 603 } 604 requests = be16_to_cpu(requests); 605 trace_nbd_negotiate_handle_info_requests(requests); 606 while (requests--) { 607 rc = nbd_opt_read(client, &request, sizeof(request), false, errp); 608 if (rc <= 0) { 609 return rc; 610 } 611 request = be16_to_cpu(request); 612 trace_nbd_negotiate_handle_info_request(request, 613 nbd_info_lookup(request)); 614 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 615 * everything else is either a request we don't know or 616 * something we send regardless of request */ 617 switch (request) { 618 case NBD_INFO_NAME: 619 sendname = true; 620 break; 621 case NBD_INFO_BLOCK_SIZE: 622 blocksize = true; 623 break; 624 } 625 } 626 if (client->optlen) { 627 return nbd_reject_length(client, false, errp); 628 } 629 630 exp = nbd_export_find(name); 631 if (!exp) { 632 g_autofree char *sane_name = nbd_sanitize_name(name); 633 634 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 635 errp, "export '%s' not present", 636 sane_name); 637 } 638 639 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 640 if (sendname) { 641 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 642 errp); 643 if (rc < 0) { 644 return rc; 645 } 646 } 647 648 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 649 * client request */ 650 if (exp->description) { 651 size_t len = strlen(exp->description); 652 653 assert(len <= NBD_MAX_STRING_SIZE); 654 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 655 len, exp->description, errp); 656 if (rc < 0) { 657 return rc; 658 } 659 } 660 661 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 662 * according to whether the client requested it, and according to 663 * whether this is OPT_INFO or OPT_GO. */ 664 /* minimum - 1 for back-compat, or actual if client will obey it. */ 665 if (client->opt == NBD_OPT_INFO || blocksize) { 666 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk); 667 } else { 668 sizes[0] = 1; 669 } 670 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 671 /* preferred - Hard-code to 4096 for now. 672 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 673 sizes[1] = MAX(4096, sizes[0]); 674 /* maximum - At most 32M, but smaller as appropriate. */ 675 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE); 676 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 677 sizes[0] = cpu_to_be32(sizes[0]); 678 sizes[1] = cpu_to_be32(sizes[1]); 679 sizes[2] = cpu_to_be32(sizes[2]); 680 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 681 sizeof(sizes), sizes, errp); 682 if (rc < 0) { 683 return rc; 684 } 685 686 /* Send NBD_INFO_EXPORT always */ 687 myflags = exp->nbdflags; 688 if (client->structured_reply) { 689 myflags |= NBD_FLAG_SEND_DF; 690 } 691 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags); 692 stq_be_p(buf, exp->size); 693 stw_be_p(buf + 8, myflags); 694 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 695 sizeof(buf), buf, errp); 696 if (rc < 0) { 697 return rc; 698 } 699 700 /* 701 * If the client is just asking for NBD_OPT_INFO, but forgot to 702 * request block sizes in a situation that would impact 703 * performance, then return an error. But for NBD_OPT_GO, we 704 * tolerate all clients, regardless of alignments. 705 */ 706 if (client->opt == NBD_OPT_INFO && !blocksize && 707 blk_get_request_alignment(exp->common.blk) > 1) { 708 return nbd_negotiate_send_rep_err(client, 709 NBD_REP_ERR_BLOCK_SIZE_REQD, 710 errp, 711 "request NBD_INFO_BLOCK_SIZE to " 712 "use this export"); 713 } 714 715 /* Final reply */ 716 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 717 if (rc < 0) { 718 return rc; 719 } 720 721 if (client->opt == NBD_OPT_GO) { 722 client->exp = exp; 723 client->check_align = check_align; 724 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 725 blk_exp_ref(&client->exp->common); 726 nbd_check_meta_export(client); 727 rc = 1; 728 } 729 return rc; 730 } 731 732 733 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 734 * new channel for all further (now-encrypted) communication. */ 735 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 736 Error **errp) 737 { 738 QIOChannel *ioc; 739 QIOChannelTLS *tioc; 740 struct NBDTLSHandshakeData data = { 0 }; 741 742 assert(client->opt == NBD_OPT_STARTTLS); 743 744 trace_nbd_negotiate_handle_starttls(); 745 ioc = client->ioc; 746 747 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 748 return NULL; 749 } 750 751 tioc = qio_channel_tls_new_server(ioc, 752 client->tlscreds, 753 client->tlsauthz, 754 errp); 755 if (!tioc) { 756 return NULL; 757 } 758 759 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 760 trace_nbd_negotiate_handle_starttls_handshake(); 761 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 762 qio_channel_tls_handshake(tioc, 763 nbd_tls_handshake, 764 &data, 765 NULL, 766 NULL); 767 768 if (!data.complete) { 769 g_main_loop_run(data.loop); 770 } 771 g_main_loop_unref(data.loop); 772 if (data.error) { 773 object_unref(OBJECT(tioc)); 774 error_propagate(errp, data.error); 775 return NULL; 776 } 777 778 return QIO_CHANNEL(tioc); 779 } 780 781 /* nbd_negotiate_send_meta_context 782 * 783 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 784 * 785 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 786 */ 787 static int nbd_negotiate_send_meta_context(NBDClient *client, 788 const char *context, 789 uint32_t context_id, 790 Error **errp) 791 { 792 NBDOptionReplyMetaContext opt; 793 struct iovec iov[] = { 794 {.iov_base = &opt, .iov_len = sizeof(opt)}, 795 {.iov_base = (void *)context, .iov_len = strlen(context)} 796 }; 797 798 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE); 799 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 800 context_id = 0; 801 } 802 803 trace_nbd_negotiate_meta_query_reply(context, context_id); 804 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 805 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 806 stl_be_p(&opt.context_id, context_id); 807 808 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 809 } 810 811 /* 812 * Return true if @query matches @pattern, or if @query is empty when 813 * the @client is performing _LIST_. 814 */ 815 static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 816 const char *query) 817 { 818 if (!*query) { 819 trace_nbd_negotiate_meta_query_parse("empty"); 820 return client->opt == NBD_OPT_LIST_META_CONTEXT; 821 } 822 if (strcmp(query, pattern) == 0) { 823 trace_nbd_negotiate_meta_query_parse(pattern); 824 return true; 825 } 826 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 827 return false; 828 } 829 830 /* 831 * Return true and adjust @str in place if it begins with @prefix. 832 */ 833 static bool nbd_strshift(const char **str, const char *prefix) 834 { 835 size_t len = strlen(prefix); 836 837 if (strncmp(*str, prefix, len) == 0) { 838 *str += len; 839 return true; 840 } 841 return false; 842 } 843 844 /* nbd_meta_base_query 845 * 846 * Handle queries to 'base' namespace. For now, only the base:allocation 847 * context is available. Return true if @query has been handled. 848 */ 849 static bool nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 850 const char *query) 851 { 852 if (!nbd_strshift(&query, "base:")) { 853 return false; 854 } 855 trace_nbd_negotiate_meta_query_parse("base:"); 856 857 if (nbd_meta_empty_or_pattern(client, "allocation", query)) { 858 meta->base_allocation = true; 859 } 860 return true; 861 } 862 863 /* nbd_meta_qemu_query 864 * 865 * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap: 866 * and qemu:allocation-depth contexts are available. Return true if @query 867 * has been handled. 868 */ 869 static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 870 const char *query) 871 { 872 size_t i; 873 874 if (!nbd_strshift(&query, "qemu:")) { 875 return false; 876 } 877 trace_nbd_negotiate_meta_query_parse("qemu:"); 878 879 if (!*query) { 880 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 881 meta->allocation_depth = meta->exp->allocation_depth; 882 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 883 } 884 trace_nbd_negotiate_meta_query_parse("empty"); 885 return true; 886 } 887 888 if (strcmp(query, "allocation-depth") == 0) { 889 trace_nbd_negotiate_meta_query_parse("allocation-depth"); 890 meta->allocation_depth = meta->exp->allocation_depth; 891 return true; 892 } 893 894 if (nbd_strshift(&query, "dirty-bitmap:")) { 895 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 896 if (!*query) { 897 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 898 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 899 } 900 trace_nbd_negotiate_meta_query_parse("empty"); 901 return true; 902 } 903 904 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 905 const char *bm_name; 906 907 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 908 if (strcmp(bm_name, query) == 0) { 909 meta->bitmaps[i] = true; 910 trace_nbd_negotiate_meta_query_parse(query); 911 return true; 912 } 913 } 914 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap match"); 915 return true; 916 } 917 918 trace_nbd_negotiate_meta_query_skip("unknown qemu context"); 919 return true; 920 } 921 922 /* nbd_negotiate_meta_query 923 * 924 * Parse namespace name and call corresponding function to parse body of the 925 * query. 926 * 927 * The only supported namespaces are 'base' and 'qemu'. 928 * 929 * Return -errno on I/O error, 0 if option was completely handled by 930 * sending a reply about inconsistent lengths, or 1 on success. */ 931 static int nbd_negotiate_meta_query(NBDClient *client, 932 NBDExportMetaContexts *meta, Error **errp) 933 { 934 int ret; 935 g_autofree char *query = NULL; 936 uint32_t len; 937 938 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 939 if (ret <= 0) { 940 return ret; 941 } 942 len = cpu_to_be32(len); 943 944 if (len > NBD_MAX_STRING_SIZE) { 945 trace_nbd_negotiate_meta_query_skip("length too long"); 946 return nbd_opt_skip(client, len, errp); 947 } 948 949 query = g_malloc(len + 1); 950 ret = nbd_opt_read(client, query, len, true, errp); 951 if (ret <= 0) { 952 return ret; 953 } 954 query[len] = '\0'; 955 956 if (nbd_meta_base_query(client, meta, query)) { 957 return 1; 958 } 959 if (nbd_meta_qemu_query(client, meta, query)) { 960 return 1; 961 } 962 963 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 964 return 1; 965 } 966 967 /* nbd_negotiate_meta_queries 968 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 969 * 970 * Return -errno on I/O error, or 0 if option was completely handled. */ 971 static int nbd_negotiate_meta_queries(NBDClient *client, 972 NBDExportMetaContexts *meta, Error **errp) 973 { 974 int ret; 975 g_autofree char *export_name = NULL; 976 g_autofree bool *bitmaps = NULL; 977 NBDExportMetaContexts local_meta = {0}; 978 uint32_t nb_queries; 979 size_t i; 980 size_t count = 0; 981 982 if (!client->structured_reply) { 983 return nbd_opt_invalid(client, errp, 984 "request option '%s' when structured reply " 985 "is not negotiated", 986 nbd_opt_lookup(client->opt)); 987 } 988 989 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 990 /* Only change the caller's meta on SET. */ 991 meta = &local_meta; 992 } 993 994 g_free(meta->bitmaps); 995 memset(meta, 0, sizeof(*meta)); 996 997 ret = nbd_opt_read_name(client, &export_name, NULL, errp); 998 if (ret <= 0) { 999 return ret; 1000 } 1001 1002 meta->exp = nbd_export_find(export_name); 1003 if (meta->exp == NULL) { 1004 g_autofree char *sane_name = nbd_sanitize_name(export_name); 1005 1006 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 1007 "export '%s' not present", sane_name); 1008 } 1009 meta->bitmaps = g_new0(bool, meta->exp->nr_export_bitmaps); 1010 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1011 bitmaps = meta->bitmaps; 1012 } 1013 1014 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp); 1015 if (ret <= 0) { 1016 return ret; 1017 } 1018 nb_queries = cpu_to_be32(nb_queries); 1019 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 1020 export_name, nb_queries); 1021 1022 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 1023 /* enable all known contexts */ 1024 meta->base_allocation = true; 1025 meta->allocation_depth = meta->exp->allocation_depth; 1026 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 1027 } else { 1028 for (i = 0; i < nb_queries; ++i) { 1029 ret = nbd_negotiate_meta_query(client, meta, errp); 1030 if (ret <= 0) { 1031 return ret; 1032 } 1033 } 1034 } 1035 1036 if (meta->base_allocation) { 1037 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1038 NBD_META_ID_BASE_ALLOCATION, 1039 errp); 1040 if (ret < 0) { 1041 return ret; 1042 } 1043 count++; 1044 } 1045 1046 if (meta->allocation_depth) { 1047 ret = nbd_negotiate_send_meta_context(client, "qemu:allocation-depth", 1048 NBD_META_ID_ALLOCATION_DEPTH, 1049 errp); 1050 if (ret < 0) { 1051 return ret; 1052 } 1053 count++; 1054 } 1055 1056 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 1057 const char *bm_name; 1058 g_autofree char *context = NULL; 1059 1060 if (!meta->bitmaps[i]) { 1061 continue; 1062 } 1063 1064 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 1065 context = g_strdup_printf("qemu:dirty-bitmap:%s", bm_name); 1066 1067 ret = nbd_negotiate_send_meta_context(client, context, 1068 NBD_META_ID_DIRTY_BITMAP + i, 1069 errp); 1070 if (ret < 0) { 1071 return ret; 1072 } 1073 count++; 1074 } 1075 1076 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1077 if (ret == 0) { 1078 meta->count = count; 1079 } 1080 1081 return ret; 1082 } 1083 1084 /* nbd_negotiate_options 1085 * Process all NBD_OPT_* client option commands, during fixed newstyle 1086 * negotiation. 1087 * Return: 1088 * -errno on error, errp is set 1089 * 0 on successful negotiation, errp is not set 1090 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1091 * errp is not set 1092 */ 1093 static int nbd_negotiate_options(NBDClient *client, Error **errp) 1094 { 1095 uint32_t flags; 1096 bool fixedNewstyle = false; 1097 bool no_zeroes = false; 1098 1099 /* Client sends: 1100 [ 0 .. 3] client flags 1101 1102 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1103 [ 0 .. 7] NBD_OPTS_MAGIC 1104 [ 8 .. 11] NBD option 1105 [12 .. 15] Data length 1106 ... Rest of request 1107 1108 [ 0 .. 7] NBD_OPTS_MAGIC 1109 [ 8 .. 11] Second NBD option 1110 [12 .. 15] Data length 1111 ... Rest of request 1112 */ 1113 1114 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1115 return -EIO; 1116 } 1117 trace_nbd_negotiate_options_flags(flags); 1118 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1119 fixedNewstyle = true; 1120 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1121 } 1122 if (flags & NBD_FLAG_C_NO_ZEROES) { 1123 no_zeroes = true; 1124 flags &= ~NBD_FLAG_C_NO_ZEROES; 1125 } 1126 if (flags != 0) { 1127 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1128 return -EINVAL; 1129 } 1130 1131 while (1) { 1132 int ret; 1133 uint32_t option, length; 1134 uint64_t magic; 1135 1136 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1137 return -EINVAL; 1138 } 1139 trace_nbd_negotiate_options_check_magic(magic); 1140 if (magic != NBD_OPTS_MAGIC) { 1141 error_setg(errp, "Bad magic received"); 1142 return -EINVAL; 1143 } 1144 1145 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1146 return -EINVAL; 1147 } 1148 client->opt = option; 1149 1150 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1151 return -EINVAL; 1152 } 1153 assert(!client->optlen); 1154 client->optlen = length; 1155 1156 if (length > NBD_MAX_BUFFER_SIZE) { 1157 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1158 length, NBD_MAX_BUFFER_SIZE); 1159 return -EINVAL; 1160 } 1161 1162 trace_nbd_negotiate_options_check_option(option, 1163 nbd_opt_lookup(option)); 1164 if (client->tlscreds && 1165 client->ioc == (QIOChannel *)client->sioc) { 1166 QIOChannel *tioc; 1167 if (!fixedNewstyle) { 1168 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1169 return -EINVAL; 1170 } 1171 switch (option) { 1172 case NBD_OPT_STARTTLS: 1173 if (length) { 1174 /* Unconditionally drop the connection if the client 1175 * can't start a TLS negotiation correctly */ 1176 return nbd_reject_length(client, true, errp); 1177 } 1178 tioc = nbd_negotiate_handle_starttls(client, errp); 1179 if (!tioc) { 1180 return -EIO; 1181 } 1182 ret = 0; 1183 object_unref(OBJECT(client->ioc)); 1184 client->ioc = QIO_CHANNEL(tioc); 1185 break; 1186 1187 case NBD_OPT_EXPORT_NAME: 1188 /* No way to return an error to client, so drop connection */ 1189 error_setg(errp, "Option 0x%x not permitted before TLS", 1190 option); 1191 return -EINVAL; 1192 1193 default: 1194 /* Let the client keep trying, unless they asked to 1195 * quit. Always try to give an error back to the 1196 * client; but when replying to OPT_ABORT, be aware 1197 * that the client may hang up before receiving the 1198 * error, in which case we are fine ignoring the 1199 * resulting EPIPE. */ 1200 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1201 option == NBD_OPT_ABORT ? NULL : errp, 1202 "Option 0x%" PRIx32 1203 " not permitted before TLS", option); 1204 if (option == NBD_OPT_ABORT) { 1205 return 1; 1206 } 1207 break; 1208 } 1209 } else if (fixedNewstyle) { 1210 switch (option) { 1211 case NBD_OPT_LIST: 1212 if (length) { 1213 ret = nbd_reject_length(client, false, errp); 1214 } else { 1215 ret = nbd_negotiate_handle_list(client, errp); 1216 } 1217 break; 1218 1219 case NBD_OPT_ABORT: 1220 /* NBD spec says we must try to reply before 1221 * disconnecting, but that we must also tolerate 1222 * guests that don't wait for our reply. */ 1223 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1224 return 1; 1225 1226 case NBD_OPT_EXPORT_NAME: 1227 return nbd_negotiate_handle_export_name(client, no_zeroes, 1228 errp); 1229 1230 case NBD_OPT_INFO: 1231 case NBD_OPT_GO: 1232 ret = nbd_negotiate_handle_info(client, errp); 1233 if (ret == 1) { 1234 assert(option == NBD_OPT_GO); 1235 return 0; 1236 } 1237 break; 1238 1239 case NBD_OPT_STARTTLS: 1240 if (length) { 1241 ret = nbd_reject_length(client, false, errp); 1242 } else if (client->tlscreds) { 1243 ret = nbd_negotiate_send_rep_err(client, 1244 NBD_REP_ERR_INVALID, errp, 1245 "TLS already enabled"); 1246 } else { 1247 ret = nbd_negotiate_send_rep_err(client, 1248 NBD_REP_ERR_POLICY, errp, 1249 "TLS not configured"); 1250 } 1251 break; 1252 1253 case NBD_OPT_STRUCTURED_REPLY: 1254 if (length) { 1255 ret = nbd_reject_length(client, false, errp); 1256 } else if (client->structured_reply) { 1257 ret = nbd_negotiate_send_rep_err( 1258 client, NBD_REP_ERR_INVALID, errp, 1259 "structured reply already negotiated"); 1260 } else { 1261 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1262 client->structured_reply = true; 1263 } 1264 break; 1265 1266 case NBD_OPT_LIST_META_CONTEXT: 1267 case NBD_OPT_SET_META_CONTEXT: 1268 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1269 errp); 1270 break; 1271 1272 default: 1273 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1274 "Unsupported option %" PRIu32 " (%s)", 1275 option, nbd_opt_lookup(option)); 1276 break; 1277 } 1278 } else { 1279 /* 1280 * If broken new-style we should drop the connection 1281 * for anything except NBD_OPT_EXPORT_NAME 1282 */ 1283 switch (option) { 1284 case NBD_OPT_EXPORT_NAME: 1285 return nbd_negotiate_handle_export_name(client, no_zeroes, 1286 errp); 1287 1288 default: 1289 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1290 option, nbd_opt_lookup(option)); 1291 return -EINVAL; 1292 } 1293 } 1294 if (ret < 0) { 1295 return ret; 1296 } 1297 } 1298 } 1299 1300 /* nbd_negotiate 1301 * Return: 1302 * -errno on error, errp is set 1303 * 0 on successful negotiation, errp is not set 1304 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1305 * errp is not set 1306 */ 1307 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1308 { 1309 ERRP_GUARD(); 1310 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1311 int ret; 1312 1313 /* Old style negotiation header, no room for options 1314 [ 0 .. 7] passwd ("NBDMAGIC") 1315 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1316 [16 .. 23] size 1317 [24 .. 27] export flags (zero-extended) 1318 [28 .. 151] reserved (0) 1319 1320 New style negotiation header, client can send options 1321 [ 0 .. 7] passwd ("NBDMAGIC") 1322 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1323 [16 .. 17] server flags (0) 1324 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1325 */ 1326 1327 qio_channel_set_blocking(client->ioc, false, NULL); 1328 1329 trace_nbd_negotiate_begin(); 1330 memcpy(buf, "NBDMAGIC", 8); 1331 1332 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1333 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1334 1335 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1336 error_prepend(errp, "write failed: "); 1337 return -EINVAL; 1338 } 1339 ret = nbd_negotiate_options(client, errp); 1340 if (ret != 0) { 1341 if (ret < 0) { 1342 error_prepend(errp, "option negotiation failed: "); 1343 } 1344 return ret; 1345 } 1346 1347 /* Attach the channel to the same AioContext as the export */ 1348 if (client->exp && client->exp->common.ctx) { 1349 qio_channel_attach_aio_context(client->ioc, client->exp->common.ctx); 1350 } 1351 1352 assert(!client->optlen); 1353 trace_nbd_negotiate_success(); 1354 1355 return 0; 1356 } 1357 1358 /* nbd_read_eof 1359 * Tries to read @size bytes from @ioc. This is a local implementation of 1360 * qio_channel_readv_all_eof. We have it here because we need it to be 1361 * interruptible and to know when the coroutine is yielding. 1362 * Returns 1 on success 1363 * 0 on eof, when no data was read (errp is not set) 1364 * negative errno on failure (errp is set) 1365 */ 1366 static inline int coroutine_fn 1367 nbd_read_eof(NBDClient *client, void *buffer, size_t size, Error **errp) 1368 { 1369 bool partial = false; 1370 1371 assert(size); 1372 while (size > 0) { 1373 struct iovec iov = { .iov_base = buffer, .iov_len = size }; 1374 ssize_t len; 1375 1376 len = qio_channel_readv(client->ioc, &iov, 1, errp); 1377 if (len == QIO_CHANNEL_ERR_BLOCK) { 1378 client->read_yielding = true; 1379 qio_channel_yield(client->ioc, G_IO_IN); 1380 client->read_yielding = false; 1381 if (client->quiescing) { 1382 return -EAGAIN; 1383 } 1384 continue; 1385 } else if (len < 0) { 1386 return -EIO; 1387 } else if (len == 0) { 1388 if (partial) { 1389 error_setg(errp, 1390 "Unexpected end-of-file before all bytes were read"); 1391 return -EIO; 1392 } else { 1393 return 0; 1394 } 1395 } 1396 1397 partial = true; 1398 size -= len; 1399 buffer = (uint8_t *) buffer + len; 1400 } 1401 return 1; 1402 } 1403 1404 static int nbd_receive_request(NBDClient *client, NBDRequest *request, 1405 Error **errp) 1406 { 1407 uint8_t buf[NBD_REQUEST_SIZE]; 1408 uint32_t magic; 1409 int ret; 1410 1411 ret = nbd_read_eof(client, buf, sizeof(buf), errp); 1412 if (ret < 0) { 1413 return ret; 1414 } 1415 1416 /* Request 1417 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1418 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1419 [ 6 .. 7] type (NBD_CMD_READ, ...) 1420 [ 8 .. 15] handle 1421 [16 .. 23] from 1422 [24 .. 27] len 1423 */ 1424 1425 magic = ldl_be_p(buf); 1426 request->flags = lduw_be_p(buf + 4); 1427 request->type = lduw_be_p(buf + 6); 1428 request->handle = ldq_be_p(buf + 8); 1429 request->from = ldq_be_p(buf + 16); 1430 request->len = ldl_be_p(buf + 24); 1431 1432 trace_nbd_receive_request(magic, request->flags, request->type, 1433 request->from, request->len); 1434 1435 if (magic != NBD_REQUEST_MAGIC) { 1436 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1437 return -EINVAL; 1438 } 1439 return 0; 1440 } 1441 1442 #define MAX_NBD_REQUESTS 16 1443 1444 void nbd_client_get(NBDClient *client) 1445 { 1446 client->refcount++; 1447 } 1448 1449 void nbd_client_put(NBDClient *client) 1450 { 1451 if (--client->refcount == 0) { 1452 /* The last reference should be dropped by client->close, 1453 * which is called by client_close. 1454 */ 1455 assert(client->closing); 1456 1457 qio_channel_detach_aio_context(client->ioc); 1458 object_unref(OBJECT(client->sioc)); 1459 object_unref(OBJECT(client->ioc)); 1460 if (client->tlscreds) { 1461 object_unref(OBJECT(client->tlscreds)); 1462 } 1463 g_free(client->tlsauthz); 1464 if (client->exp) { 1465 QTAILQ_REMOVE(&client->exp->clients, client, next); 1466 blk_exp_unref(&client->exp->common); 1467 } 1468 g_free(client->export_meta.bitmaps); 1469 g_free(client); 1470 } 1471 } 1472 1473 static void client_close(NBDClient *client, bool negotiated) 1474 { 1475 if (client->closing) { 1476 return; 1477 } 1478 1479 client->closing = true; 1480 1481 /* Force requests to finish. They will drop their own references, 1482 * then we'll close the socket and free the NBDClient. 1483 */ 1484 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1485 NULL); 1486 1487 /* Also tell the client, so that they release their reference. */ 1488 if (client->close_fn) { 1489 client->close_fn(client, negotiated); 1490 } 1491 } 1492 1493 static NBDRequestData *nbd_request_get(NBDClient *client) 1494 { 1495 NBDRequestData *req; 1496 1497 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1498 client->nb_requests++; 1499 1500 req = g_new0(NBDRequestData, 1); 1501 nbd_client_get(client); 1502 req->client = client; 1503 return req; 1504 } 1505 1506 static void nbd_request_put(NBDRequestData *req) 1507 { 1508 NBDClient *client = req->client; 1509 1510 if (req->data) { 1511 qemu_vfree(req->data); 1512 } 1513 g_free(req); 1514 1515 client->nb_requests--; 1516 nbd_client_receive_next_request(client); 1517 1518 nbd_client_put(client); 1519 } 1520 1521 static void blk_aio_attached(AioContext *ctx, void *opaque) 1522 { 1523 NBDExport *exp = opaque; 1524 NBDClient *client; 1525 1526 trace_nbd_blk_aio_attached(exp->name, ctx); 1527 1528 exp->common.ctx = ctx; 1529 1530 QTAILQ_FOREACH(client, &exp->clients, next) { 1531 qio_channel_attach_aio_context(client->ioc, ctx); 1532 1533 assert(client->recv_coroutine == NULL); 1534 assert(client->send_coroutine == NULL); 1535 1536 if (client->quiescing) { 1537 client->quiescing = false; 1538 nbd_client_receive_next_request(client); 1539 } 1540 } 1541 } 1542 1543 static void nbd_aio_detach_bh(void *opaque) 1544 { 1545 NBDExport *exp = opaque; 1546 NBDClient *client; 1547 1548 QTAILQ_FOREACH(client, &exp->clients, next) { 1549 qio_channel_detach_aio_context(client->ioc); 1550 client->quiescing = true; 1551 1552 if (client->recv_coroutine) { 1553 if (client->read_yielding) { 1554 qemu_aio_coroutine_enter(exp->common.ctx, 1555 client->recv_coroutine); 1556 } else { 1557 AIO_WAIT_WHILE(exp->common.ctx, client->recv_coroutine != NULL); 1558 } 1559 } 1560 1561 if (client->send_coroutine) { 1562 AIO_WAIT_WHILE(exp->common.ctx, client->send_coroutine != NULL); 1563 } 1564 } 1565 } 1566 1567 static void blk_aio_detach(void *opaque) 1568 { 1569 NBDExport *exp = opaque; 1570 1571 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx); 1572 1573 aio_wait_bh_oneshot(exp->common.ctx, nbd_aio_detach_bh, exp); 1574 1575 exp->common.ctx = NULL; 1576 } 1577 1578 static void nbd_eject_notifier(Notifier *n, void *data) 1579 { 1580 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1581 1582 blk_exp_request_shutdown(&exp->common); 1583 } 1584 1585 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) 1586 { 1587 NBDExport *nbd_exp = container_of(exp, NBDExport, common); 1588 assert(exp->drv == &blk_exp_nbd); 1589 assert(nbd_exp->eject_notifier_blk == NULL); 1590 1591 blk_ref(blk); 1592 nbd_exp->eject_notifier_blk = blk; 1593 nbd_exp->eject_notifier.notify = nbd_eject_notifier; 1594 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier); 1595 } 1596 1597 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, 1598 Error **errp) 1599 { 1600 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1601 BlockExportOptionsNbd *arg = &exp_args->u.nbd; 1602 BlockBackend *blk = blk_exp->blk; 1603 int64_t size; 1604 uint64_t perm, shared_perm; 1605 bool readonly = !exp_args->writable; 1606 bool shared = !exp_args->writable; 1607 strList *bitmaps; 1608 size_t i; 1609 int ret; 1610 1611 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); 1612 1613 if (!nbd_server_is_running()) { 1614 error_setg(errp, "NBD server not running"); 1615 return -EINVAL; 1616 } 1617 1618 if (!arg->has_name) { 1619 arg->name = exp_args->node_name; 1620 } 1621 1622 if (strlen(arg->name) > NBD_MAX_STRING_SIZE) { 1623 error_setg(errp, "export name '%s' too long", arg->name); 1624 return -EINVAL; 1625 } 1626 1627 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) { 1628 error_setg(errp, "description '%s' too long", arg->description); 1629 return -EINVAL; 1630 } 1631 1632 if (nbd_export_find(arg->name)) { 1633 error_setg(errp, "NBD server already has export named '%s'", arg->name); 1634 return -EEXIST; 1635 } 1636 1637 size = blk_getlength(blk); 1638 if (size < 0) { 1639 error_setg_errno(errp, -size, 1640 "Failed to determine the NBD export's length"); 1641 return size; 1642 } 1643 1644 /* Don't allow resize while the NBD server is running, otherwise we don't 1645 * care what happens with the node. */ 1646 blk_get_perm(blk, &perm, &shared_perm); 1647 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); 1648 if (ret < 0) { 1649 return ret; 1650 } 1651 1652 QTAILQ_INIT(&exp->clients); 1653 exp->name = g_strdup(arg->name); 1654 exp->description = g_strdup(arg->description); 1655 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1656 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1657 if (readonly) { 1658 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1659 if (shared) { 1660 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1661 } 1662 } else { 1663 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1664 NBD_FLAG_SEND_FAST_ZERO); 1665 } 1666 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1667 1668 for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) { 1669 exp->nr_export_bitmaps++; 1670 } 1671 exp->export_bitmaps = g_new0(BdrvDirtyBitmap *, exp->nr_export_bitmaps); 1672 for (i = 0, bitmaps = arg->bitmaps; bitmaps; 1673 i++, bitmaps = bitmaps->next) { 1674 const char *bitmap = bitmaps->value; 1675 BlockDriverState *bs = blk_bs(blk); 1676 BdrvDirtyBitmap *bm = NULL; 1677 1678 while (bs) { 1679 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1680 if (bm != NULL) { 1681 break; 1682 } 1683 1684 bs = bdrv_filter_or_cow_bs(bs); 1685 } 1686 1687 if (bm == NULL) { 1688 ret = -ENOENT; 1689 error_setg(errp, "Bitmap '%s' is not found", bitmap); 1690 goto fail; 1691 } 1692 1693 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1694 ret = -EINVAL; 1695 goto fail; 1696 } 1697 1698 if (readonly && bdrv_is_writable(bs) && 1699 bdrv_dirty_bitmap_enabled(bm)) { 1700 ret = -EINVAL; 1701 error_setg(errp, 1702 "Enabled bitmap '%s' incompatible with readonly export", 1703 bitmap); 1704 goto fail; 1705 } 1706 1707 exp->export_bitmaps[i] = bm; 1708 assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE); 1709 } 1710 1711 /* Mark bitmaps busy in a separate loop, to simplify roll-back concerns. */ 1712 for (i = 0; i < exp->nr_export_bitmaps; i++) { 1713 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true); 1714 } 1715 1716 exp->allocation_depth = arg->allocation_depth; 1717 1718 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1719 1720 QTAILQ_INSERT_TAIL(&exports, exp, next); 1721 1722 return 0; 1723 1724 fail: 1725 g_free(exp->export_bitmaps); 1726 g_free(exp->name); 1727 g_free(exp->description); 1728 return ret; 1729 } 1730 1731 NBDExport *nbd_export_find(const char *name) 1732 { 1733 NBDExport *exp; 1734 QTAILQ_FOREACH(exp, &exports, next) { 1735 if (strcmp(name, exp->name) == 0) { 1736 return exp; 1737 } 1738 } 1739 1740 return NULL; 1741 } 1742 1743 AioContext * 1744 nbd_export_aio_context(NBDExport *exp) 1745 { 1746 return exp->common.ctx; 1747 } 1748 1749 static void nbd_export_request_shutdown(BlockExport *blk_exp) 1750 { 1751 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1752 NBDClient *client, *next; 1753 1754 blk_exp_ref(&exp->common); 1755 /* 1756 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1757 * close mode that stops advertising the export to new clients but 1758 * still permits existing clients to run to completion? Because of 1759 * that possibility, nbd_export_close() can be called more than 1760 * once on an export. 1761 */ 1762 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1763 client_close(client, true); 1764 } 1765 if (exp->name) { 1766 g_free(exp->name); 1767 exp->name = NULL; 1768 QTAILQ_REMOVE(&exports, exp, next); 1769 } 1770 blk_exp_unref(&exp->common); 1771 } 1772 1773 static void nbd_export_delete(BlockExport *blk_exp) 1774 { 1775 size_t i; 1776 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1777 1778 assert(exp->name == NULL); 1779 assert(QTAILQ_EMPTY(&exp->clients)); 1780 1781 g_free(exp->description); 1782 exp->description = NULL; 1783 1784 if (exp->common.blk) { 1785 if (exp->eject_notifier_blk) { 1786 notifier_remove(&exp->eject_notifier); 1787 blk_unref(exp->eject_notifier_blk); 1788 } 1789 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached, 1790 blk_aio_detach, exp); 1791 } 1792 1793 for (i = 0; i < exp->nr_export_bitmaps; i++) { 1794 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], false); 1795 } 1796 } 1797 1798 const BlockExportDriver blk_exp_nbd = { 1799 .type = BLOCK_EXPORT_TYPE_NBD, 1800 .instance_size = sizeof(NBDExport), 1801 .create = nbd_export_create, 1802 .delete = nbd_export_delete, 1803 .request_shutdown = nbd_export_request_shutdown, 1804 }; 1805 1806 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1807 unsigned niov, Error **errp) 1808 { 1809 int ret; 1810 1811 g_assert(qemu_in_coroutine()); 1812 qemu_co_mutex_lock(&client->send_lock); 1813 client->send_coroutine = qemu_coroutine_self(); 1814 1815 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1816 1817 client->send_coroutine = NULL; 1818 qemu_co_mutex_unlock(&client->send_lock); 1819 1820 return ret; 1821 } 1822 1823 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1824 uint64_t handle) 1825 { 1826 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1827 stl_be_p(&reply->error, error); 1828 stq_be_p(&reply->handle, handle); 1829 } 1830 1831 static int nbd_co_send_simple_reply(NBDClient *client, 1832 uint64_t handle, 1833 uint32_t error, 1834 void *data, 1835 size_t len, 1836 Error **errp) 1837 { 1838 NBDSimpleReply reply; 1839 int nbd_err = system_errno_to_nbd_errno(error); 1840 struct iovec iov[] = { 1841 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1842 {.iov_base = data, .iov_len = len} 1843 }; 1844 1845 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1846 len); 1847 set_be_simple_reply(&reply, nbd_err, handle); 1848 1849 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1850 } 1851 1852 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1853 uint16_t type, uint64_t handle, uint32_t length) 1854 { 1855 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1856 stw_be_p(&chunk->flags, flags); 1857 stw_be_p(&chunk->type, type); 1858 stq_be_p(&chunk->handle, handle); 1859 stl_be_p(&chunk->length, length); 1860 } 1861 1862 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1863 uint64_t handle, 1864 Error **errp) 1865 { 1866 NBDStructuredReplyChunk chunk; 1867 struct iovec iov[] = { 1868 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1869 }; 1870 1871 trace_nbd_co_send_structured_done(handle); 1872 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1873 1874 return nbd_co_send_iov(client, iov, 1, errp); 1875 } 1876 1877 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1878 uint64_t handle, 1879 uint64_t offset, 1880 void *data, 1881 size_t size, 1882 bool final, 1883 Error **errp) 1884 { 1885 NBDStructuredReadData chunk; 1886 struct iovec iov[] = { 1887 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1888 {.iov_base = data, .iov_len = size} 1889 }; 1890 1891 assert(size); 1892 trace_nbd_co_send_structured_read(handle, offset, data, size); 1893 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1894 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1895 sizeof(chunk) - sizeof(chunk.h) + size); 1896 stq_be_p(&chunk.offset, offset); 1897 1898 return nbd_co_send_iov(client, iov, 2, errp); 1899 } 1900 1901 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1902 uint64_t handle, 1903 uint32_t error, 1904 const char *msg, 1905 Error **errp) 1906 { 1907 NBDStructuredError chunk; 1908 int nbd_err = system_errno_to_nbd_errno(error); 1909 struct iovec iov[] = { 1910 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1911 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1912 }; 1913 1914 assert(nbd_err); 1915 trace_nbd_co_send_structured_error(handle, nbd_err, 1916 nbd_err_lookup(nbd_err), msg ? msg : ""); 1917 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1918 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1919 stl_be_p(&chunk.error, nbd_err); 1920 stw_be_p(&chunk.message_length, iov[1].iov_len); 1921 1922 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1923 } 1924 1925 /* Do a sparse read and send the structured reply to the client. 1926 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1927 * reported to the client, at which point this function succeeds. 1928 */ 1929 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1930 uint64_t handle, 1931 uint64_t offset, 1932 uint8_t *data, 1933 size_t size, 1934 Error **errp) 1935 { 1936 int ret = 0; 1937 NBDExport *exp = client->exp; 1938 size_t progress = 0; 1939 1940 while (progress < size) { 1941 int64_t pnum; 1942 int status = bdrv_block_status_above(blk_bs(exp->common.blk), NULL, 1943 offset + progress, 1944 size - progress, &pnum, NULL, 1945 NULL); 1946 bool final; 1947 1948 if (status < 0) { 1949 char *msg = g_strdup_printf("unable to check for holes: %s", 1950 strerror(-status)); 1951 1952 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1953 errp); 1954 g_free(msg); 1955 return ret; 1956 } 1957 assert(pnum && pnum <= size - progress); 1958 final = progress + pnum == size; 1959 if (status & BDRV_BLOCK_ZERO) { 1960 NBDStructuredReadHole chunk; 1961 struct iovec iov[] = { 1962 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1963 }; 1964 1965 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1966 pnum); 1967 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1968 NBD_REPLY_TYPE_OFFSET_HOLE, 1969 handle, sizeof(chunk) - sizeof(chunk.h)); 1970 stq_be_p(&chunk.offset, offset + progress); 1971 stl_be_p(&chunk.length, pnum); 1972 ret = nbd_co_send_iov(client, iov, 1, errp); 1973 } else { 1974 ret = blk_pread(exp->common.blk, offset + progress, 1975 data + progress, pnum); 1976 if (ret < 0) { 1977 error_setg_errno(errp, -ret, "reading from file failed"); 1978 break; 1979 } 1980 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1981 data + progress, pnum, final, 1982 errp); 1983 } 1984 1985 if (ret < 0) { 1986 break; 1987 } 1988 progress += pnum; 1989 } 1990 return ret; 1991 } 1992 1993 typedef struct NBDExtentArray { 1994 NBDExtent *extents; 1995 unsigned int nb_alloc; 1996 unsigned int count; 1997 uint64_t total_length; 1998 bool can_add; 1999 bool converted_to_be; 2000 } NBDExtentArray; 2001 2002 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc) 2003 { 2004 NBDExtentArray *ea = g_new0(NBDExtentArray, 1); 2005 2006 ea->nb_alloc = nb_alloc; 2007 ea->extents = g_new(NBDExtent, nb_alloc); 2008 ea->can_add = true; 2009 2010 return ea; 2011 } 2012 2013 static void nbd_extent_array_free(NBDExtentArray *ea) 2014 { 2015 g_free(ea->extents); 2016 g_free(ea); 2017 } 2018 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free); 2019 2020 /* Further modifications of the array after conversion are abandoned */ 2021 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea) 2022 { 2023 int i; 2024 2025 assert(!ea->converted_to_be); 2026 ea->can_add = false; 2027 ea->converted_to_be = true; 2028 2029 for (i = 0; i < ea->count; i++) { 2030 ea->extents[i].flags = cpu_to_be32(ea->extents[i].flags); 2031 ea->extents[i].length = cpu_to_be32(ea->extents[i].length); 2032 } 2033 } 2034 2035 /* 2036 * Add extent to NBDExtentArray. If extent can't be added (no available space), 2037 * return -1. 2038 * For safety, when returning -1 for the first time, .can_add is set to false, 2039 * further call to nbd_extent_array_add() will crash. 2040 * (to avoid the situation, when after failing to add an extent (returned -1), 2041 * user miss this failure and add another extent, which is successfully added 2042 * (array is full, but new extent may be squashed into the last one), then we 2043 * have invalid array with skipped extent) 2044 */ 2045 static int nbd_extent_array_add(NBDExtentArray *ea, 2046 uint32_t length, uint32_t flags) 2047 { 2048 assert(ea->can_add); 2049 2050 if (!length) { 2051 return 0; 2052 } 2053 2054 /* Extend previous extent if flags are the same */ 2055 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) { 2056 uint64_t sum = (uint64_t)length + ea->extents[ea->count - 1].length; 2057 2058 if (sum <= UINT32_MAX) { 2059 ea->extents[ea->count - 1].length = sum; 2060 ea->total_length += length; 2061 return 0; 2062 } 2063 } 2064 2065 if (ea->count >= ea->nb_alloc) { 2066 ea->can_add = false; 2067 return -1; 2068 } 2069 2070 ea->total_length += length; 2071 ea->extents[ea->count] = (NBDExtent) {.length = length, .flags = flags}; 2072 ea->count++; 2073 2074 return 0; 2075 } 2076 2077 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 2078 uint64_t bytes, NBDExtentArray *ea) 2079 { 2080 while (bytes) { 2081 uint32_t flags; 2082 int64_t num; 2083 int ret = bdrv_block_status_above(bs, NULL, offset, bytes, &num, 2084 NULL, NULL); 2085 2086 if (ret < 0) { 2087 return ret; 2088 } 2089 2090 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 2091 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 2092 2093 if (nbd_extent_array_add(ea, num, flags) < 0) { 2094 return 0; 2095 } 2096 2097 offset += num; 2098 bytes -= num; 2099 } 2100 2101 return 0; 2102 } 2103 2104 static int blockalloc_to_extents(BlockDriverState *bs, uint64_t offset, 2105 uint64_t bytes, NBDExtentArray *ea) 2106 { 2107 while (bytes) { 2108 int64_t num; 2109 int ret = bdrv_is_allocated_above(bs, NULL, false, offset, bytes, 2110 &num); 2111 2112 if (ret < 0) { 2113 return ret; 2114 } 2115 2116 if (nbd_extent_array_add(ea, num, ret) < 0) { 2117 return 0; 2118 } 2119 2120 offset += num; 2121 bytes -= num; 2122 } 2123 2124 return 0; 2125 } 2126 2127 /* 2128 * nbd_co_send_extents 2129 * 2130 * @ea is converted to BE by the function 2131 * @last controls whether NBD_REPLY_FLAG_DONE is sent. 2132 */ 2133 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 2134 NBDExtentArray *ea, 2135 bool last, uint32_t context_id, Error **errp) 2136 { 2137 NBDStructuredMeta chunk; 2138 struct iovec iov[] = { 2139 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2140 {.iov_base = ea->extents, .iov_len = ea->count * sizeof(ea->extents[0])} 2141 }; 2142 2143 nbd_extent_array_convert_to_be(ea); 2144 2145 trace_nbd_co_send_extents(handle, ea->count, context_id, ea->total_length, 2146 last); 2147 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 2148 NBD_REPLY_TYPE_BLOCK_STATUS, 2149 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 2150 stl_be_p(&chunk.context_id, context_id); 2151 2152 return nbd_co_send_iov(client, iov, 2, errp); 2153 } 2154 2155 /* Get block status from the exported device and send it to the client */ 2156 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 2157 BlockDriverState *bs, uint64_t offset, 2158 uint32_t length, bool dont_fragment, 2159 bool last, uint32_t context_id, 2160 Error **errp) 2161 { 2162 int ret; 2163 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2164 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); 2165 2166 if (context_id == NBD_META_ID_BASE_ALLOCATION) { 2167 ret = blockstatus_to_extents(bs, offset, length, ea); 2168 } else { 2169 ret = blockalloc_to_extents(bs, offset, length, ea); 2170 } 2171 if (ret < 0) { 2172 return nbd_co_send_structured_error( 2173 client, handle, -ret, "can't get block status", errp); 2174 } 2175 2176 return nbd_co_send_extents(client, handle, ea, last, context_id, errp); 2177 } 2178 2179 /* Populate @ea from a dirty bitmap. */ 2180 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap, 2181 uint64_t offset, uint64_t length, 2182 NBDExtentArray *es) 2183 { 2184 int64_t start, dirty_start, dirty_count; 2185 int64_t end = offset + length; 2186 bool full = false; 2187 2188 bdrv_dirty_bitmap_lock(bitmap); 2189 2190 for (start = offset; 2191 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX, 2192 &dirty_start, &dirty_count); 2193 start = dirty_start + dirty_count) 2194 { 2195 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) || 2196 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0)) 2197 { 2198 full = true; 2199 break; 2200 } 2201 } 2202 2203 if (!full) { 2204 /* last non dirty extent, nothing to do if array is now full */ 2205 (void) nbd_extent_array_add(es, end - start, 0); 2206 } 2207 2208 bdrv_dirty_bitmap_unlock(bitmap); 2209 } 2210 2211 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2212 BdrvDirtyBitmap *bitmap, uint64_t offset, 2213 uint32_t length, bool dont_fragment, bool last, 2214 uint32_t context_id, Error **errp) 2215 { 2216 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2217 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); 2218 2219 bitmap_to_extents(bitmap, offset, length, ea); 2220 2221 return nbd_co_send_extents(client, handle, ea, last, context_id, errp); 2222 } 2223 2224 /* nbd_co_receive_request 2225 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2226 * connection right away, -EAGAIN to indicate we were interrupted and the 2227 * channel should be quiesced, and any other negative value to report an error 2228 * to the client (although the caller may still need to disconnect after 2229 * reporting the error). 2230 */ 2231 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2232 Error **errp) 2233 { 2234 NBDClient *client = req->client; 2235 int valid_flags; 2236 int ret; 2237 2238 g_assert(qemu_in_coroutine()); 2239 assert(client->recv_coroutine == qemu_coroutine_self()); 2240 ret = nbd_receive_request(client, request, errp); 2241 if (ret < 0) { 2242 return ret; 2243 } 2244 2245 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2246 nbd_cmd_lookup(request->type)); 2247 2248 if (request->type != NBD_CMD_WRITE) { 2249 /* No payload, we are ready to read the next request. */ 2250 req->complete = true; 2251 } 2252 2253 if (request->type == NBD_CMD_DISC) { 2254 /* Special case: we're going to disconnect without a reply, 2255 * whether or not flags, from, or len are bogus */ 2256 return -EIO; 2257 } 2258 2259 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2260 request->type == NBD_CMD_CACHE) 2261 { 2262 if (request->len > NBD_MAX_BUFFER_SIZE) { 2263 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2264 request->len, NBD_MAX_BUFFER_SIZE); 2265 return -EINVAL; 2266 } 2267 2268 if (request->type != NBD_CMD_CACHE) { 2269 req->data = blk_try_blockalign(client->exp->common.blk, 2270 request->len); 2271 if (req->data == NULL) { 2272 error_setg(errp, "No memory"); 2273 return -ENOMEM; 2274 } 2275 } 2276 } 2277 2278 if (request->type == NBD_CMD_WRITE) { 2279 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2280 errp) < 0) 2281 { 2282 return -EIO; 2283 } 2284 req->complete = true; 2285 2286 trace_nbd_co_receive_request_payload_received(request->handle, 2287 request->len); 2288 } 2289 2290 /* Sanity checks. */ 2291 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2292 (request->type == NBD_CMD_WRITE || 2293 request->type == NBD_CMD_WRITE_ZEROES || 2294 request->type == NBD_CMD_TRIM)) { 2295 error_setg(errp, "Export is read-only"); 2296 return -EROFS; 2297 } 2298 if (request->from > client->exp->size || 2299 request->len > client->exp->size - request->from) { 2300 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2301 ", Size: %" PRIu64, request->from, request->len, 2302 client->exp->size); 2303 return (request->type == NBD_CMD_WRITE || 2304 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2305 } 2306 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2307 client->check_align)) { 2308 /* 2309 * The block layer gracefully handles unaligned requests, but 2310 * it's still worth tracing client non-compliance 2311 */ 2312 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2313 request->from, 2314 request->len, 2315 client->check_align); 2316 } 2317 valid_flags = NBD_CMD_FLAG_FUA; 2318 if (request->type == NBD_CMD_READ && client->structured_reply) { 2319 valid_flags |= NBD_CMD_FLAG_DF; 2320 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2321 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2322 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2323 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2324 } 2325 if (request->flags & ~valid_flags) { 2326 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2327 nbd_cmd_lookup(request->type), request->flags); 2328 return -EINVAL; 2329 } 2330 2331 return 0; 2332 } 2333 2334 /* Send simple reply without a payload, or a structured error 2335 * @error_msg is ignored if @ret >= 0 2336 * Returns 0 if connection is still live, -errno on failure to talk to client 2337 */ 2338 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2339 uint64_t handle, 2340 int ret, 2341 const char *error_msg, 2342 Error **errp) 2343 { 2344 if (client->structured_reply && ret < 0) { 2345 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2346 errp); 2347 } else { 2348 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2349 NULL, 0, errp); 2350 } 2351 } 2352 2353 /* Handle NBD_CMD_READ request. 2354 * Return -errno if sending fails. Other errors are reported directly to the 2355 * client as an error reply. */ 2356 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2357 uint8_t *data, Error **errp) 2358 { 2359 int ret; 2360 NBDExport *exp = client->exp; 2361 2362 assert(request->type == NBD_CMD_READ); 2363 2364 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2365 if (request->flags & NBD_CMD_FLAG_FUA) { 2366 ret = blk_co_flush(exp->common.blk); 2367 if (ret < 0) { 2368 return nbd_send_generic_reply(client, request->handle, ret, 2369 "flush failed", errp); 2370 } 2371 } 2372 2373 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2374 request->len) 2375 { 2376 return nbd_co_send_sparse_read(client, request->handle, request->from, 2377 data, request->len, errp); 2378 } 2379 2380 ret = blk_pread(exp->common.blk, request->from, data, request->len); 2381 if (ret < 0) { 2382 return nbd_send_generic_reply(client, request->handle, ret, 2383 "reading from file failed", errp); 2384 } 2385 2386 if (client->structured_reply) { 2387 if (request->len) { 2388 return nbd_co_send_structured_read(client, request->handle, 2389 request->from, data, 2390 request->len, true, errp); 2391 } else { 2392 return nbd_co_send_structured_done(client, request->handle, errp); 2393 } 2394 } else { 2395 return nbd_co_send_simple_reply(client, request->handle, 0, 2396 data, request->len, errp); 2397 } 2398 } 2399 2400 /* 2401 * nbd_do_cmd_cache 2402 * 2403 * Handle NBD_CMD_CACHE request. 2404 * Return -errno if sending fails. Other errors are reported directly to the 2405 * client as an error reply. 2406 */ 2407 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2408 Error **errp) 2409 { 2410 int ret; 2411 NBDExport *exp = client->exp; 2412 2413 assert(request->type == NBD_CMD_CACHE); 2414 2415 ret = blk_co_preadv(exp->common.blk, request->from, request->len, 2416 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2417 2418 return nbd_send_generic_reply(client, request->handle, ret, 2419 "caching data failed", errp); 2420 } 2421 2422 /* Handle NBD request. 2423 * Return -errno if sending fails. Other errors are reported directly to the 2424 * client as an error reply. */ 2425 static coroutine_fn int nbd_handle_request(NBDClient *client, 2426 NBDRequest *request, 2427 uint8_t *data, Error **errp) 2428 { 2429 int ret; 2430 int flags; 2431 NBDExport *exp = client->exp; 2432 char *msg; 2433 size_t i; 2434 2435 switch (request->type) { 2436 case NBD_CMD_CACHE: 2437 return nbd_do_cmd_cache(client, request, errp); 2438 2439 case NBD_CMD_READ: 2440 return nbd_do_cmd_read(client, request, data, errp); 2441 2442 case NBD_CMD_WRITE: 2443 flags = 0; 2444 if (request->flags & NBD_CMD_FLAG_FUA) { 2445 flags |= BDRV_REQ_FUA; 2446 } 2447 ret = blk_pwrite(exp->common.blk, request->from, data, request->len, 2448 flags); 2449 return nbd_send_generic_reply(client, request->handle, ret, 2450 "writing to file failed", errp); 2451 2452 case NBD_CMD_WRITE_ZEROES: 2453 flags = 0; 2454 if (request->flags & NBD_CMD_FLAG_FUA) { 2455 flags |= BDRV_REQ_FUA; 2456 } 2457 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2458 flags |= BDRV_REQ_MAY_UNMAP; 2459 } 2460 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2461 flags |= BDRV_REQ_NO_FALLBACK; 2462 } 2463 ret = 0; 2464 /* FIXME simplify this when blk_pwrite_zeroes switches to 64-bit */ 2465 while (ret >= 0 && request->len) { 2466 int align = client->check_align ?: 1; 2467 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, 2468 align)); 2469 ret = blk_pwrite_zeroes(exp->common.blk, request->from, len, flags); 2470 request->len -= len; 2471 request->from += len; 2472 } 2473 return nbd_send_generic_reply(client, request->handle, ret, 2474 "writing to file failed", errp); 2475 2476 case NBD_CMD_DISC: 2477 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2478 abort(); 2479 2480 case NBD_CMD_FLUSH: 2481 ret = blk_co_flush(exp->common.blk); 2482 return nbd_send_generic_reply(client, request->handle, ret, 2483 "flush failed", errp); 2484 2485 case NBD_CMD_TRIM: 2486 ret = 0; 2487 /* FIXME simplify this when blk_co_pdiscard switches to 64-bit */ 2488 while (ret >= 0 && request->len) { 2489 int align = client->check_align ?: 1; 2490 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, 2491 align)); 2492 ret = blk_co_pdiscard(exp->common.blk, request->from, len); 2493 request->len -= len; 2494 request->from += len; 2495 } 2496 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) { 2497 ret = blk_co_flush(exp->common.blk); 2498 } 2499 return nbd_send_generic_reply(client, request->handle, ret, 2500 "discard failed", errp); 2501 2502 case NBD_CMD_BLOCK_STATUS: 2503 if (!request->len) { 2504 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2505 "need non-zero length", errp); 2506 } 2507 if (client->export_meta.count) { 2508 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2509 int contexts_remaining = client->export_meta.count; 2510 2511 if (client->export_meta.base_allocation) { 2512 ret = nbd_co_send_block_status(client, request->handle, 2513 blk_bs(exp->common.blk), 2514 request->from, 2515 request->len, dont_fragment, 2516 !--contexts_remaining, 2517 NBD_META_ID_BASE_ALLOCATION, 2518 errp); 2519 if (ret < 0) { 2520 return ret; 2521 } 2522 } 2523 2524 if (client->export_meta.allocation_depth) { 2525 ret = nbd_co_send_block_status(client, request->handle, 2526 blk_bs(exp->common.blk), 2527 request->from, request->len, 2528 dont_fragment, 2529 !--contexts_remaining, 2530 NBD_META_ID_ALLOCATION_DEPTH, 2531 errp); 2532 if (ret < 0) { 2533 return ret; 2534 } 2535 } 2536 2537 for (i = 0; i < client->exp->nr_export_bitmaps; i++) { 2538 if (!client->export_meta.bitmaps[i]) { 2539 continue; 2540 } 2541 ret = nbd_co_send_bitmap(client, request->handle, 2542 client->exp->export_bitmaps[i], 2543 request->from, request->len, 2544 dont_fragment, !--contexts_remaining, 2545 NBD_META_ID_DIRTY_BITMAP + i, errp); 2546 if (ret < 0) { 2547 return ret; 2548 } 2549 } 2550 2551 assert(!contexts_remaining); 2552 2553 return 0; 2554 } else { 2555 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2556 "CMD_BLOCK_STATUS not negotiated", 2557 errp); 2558 } 2559 2560 default: 2561 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2562 request->type); 2563 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2564 errp); 2565 g_free(msg); 2566 return ret; 2567 } 2568 } 2569 2570 /* Owns a reference to the NBDClient passed as opaque. */ 2571 static coroutine_fn void nbd_trip(void *opaque) 2572 { 2573 NBDClient *client = opaque; 2574 NBDRequestData *req; 2575 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2576 int ret; 2577 Error *local_err = NULL; 2578 2579 trace_nbd_trip(); 2580 if (client->closing) { 2581 nbd_client_put(client); 2582 return; 2583 } 2584 2585 if (client->quiescing) { 2586 /* 2587 * We're switching between AIO contexts. Don't attempt to receive a new 2588 * request and kick the main context which may be waiting for us. 2589 */ 2590 nbd_client_put(client); 2591 client->recv_coroutine = NULL; 2592 aio_wait_kick(); 2593 return; 2594 } 2595 2596 req = nbd_request_get(client); 2597 ret = nbd_co_receive_request(req, &request, &local_err); 2598 client->recv_coroutine = NULL; 2599 2600 if (client->closing) { 2601 /* 2602 * The client may be closed when we are blocked in 2603 * nbd_co_receive_request() 2604 */ 2605 goto done; 2606 } 2607 2608 if (ret == -EAGAIN) { 2609 assert(client->quiescing); 2610 goto done; 2611 } 2612 2613 nbd_client_receive_next_request(client); 2614 if (ret == -EIO) { 2615 goto disconnect; 2616 } 2617 2618 if (ret < 0) { 2619 /* It wans't -EIO, so, according to nbd_co_receive_request() 2620 * semantics, we should return the error to the client. */ 2621 Error *export_err = local_err; 2622 2623 local_err = NULL; 2624 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2625 error_get_pretty(export_err), &local_err); 2626 error_free(export_err); 2627 } else { 2628 ret = nbd_handle_request(client, &request, req->data, &local_err); 2629 } 2630 if (ret < 0) { 2631 error_prepend(&local_err, "Failed to send reply: "); 2632 goto disconnect; 2633 } 2634 2635 /* We must disconnect after NBD_CMD_WRITE if we did not 2636 * read the payload. 2637 */ 2638 if (!req->complete) { 2639 error_setg(&local_err, "Request handling failed in intermediate state"); 2640 goto disconnect; 2641 } 2642 2643 done: 2644 nbd_request_put(req); 2645 nbd_client_put(client); 2646 return; 2647 2648 disconnect: 2649 if (local_err) { 2650 error_reportf_err(local_err, "Disconnect client, due to: "); 2651 } 2652 nbd_request_put(req); 2653 client_close(client, true); 2654 nbd_client_put(client); 2655 } 2656 2657 static void nbd_client_receive_next_request(NBDClient *client) 2658 { 2659 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS && 2660 !client->quiescing) { 2661 nbd_client_get(client); 2662 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2663 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine); 2664 } 2665 } 2666 2667 static coroutine_fn void nbd_co_client_start(void *opaque) 2668 { 2669 NBDClient *client = opaque; 2670 Error *local_err = NULL; 2671 2672 qemu_co_mutex_init(&client->send_lock); 2673 2674 if (nbd_negotiate(client, &local_err)) { 2675 if (local_err) { 2676 error_report_err(local_err); 2677 } 2678 client_close(client, false); 2679 return; 2680 } 2681 2682 nbd_client_receive_next_request(client); 2683 } 2684 2685 /* 2686 * Create a new client listener using the given channel @sioc. 2687 * Begin servicing it in a coroutine. When the connection closes, call 2688 * @close_fn with an indication of whether the client completed negotiation. 2689 */ 2690 void nbd_client_new(QIOChannelSocket *sioc, 2691 QCryptoTLSCreds *tlscreds, 2692 const char *tlsauthz, 2693 void (*close_fn)(NBDClient *, bool)) 2694 { 2695 NBDClient *client; 2696 Coroutine *co; 2697 2698 client = g_new0(NBDClient, 1); 2699 client->refcount = 1; 2700 client->tlscreds = tlscreds; 2701 if (tlscreds) { 2702 object_ref(OBJECT(client->tlscreds)); 2703 } 2704 client->tlsauthz = g_strdup(tlsauthz); 2705 client->sioc = sioc; 2706 object_ref(OBJECT(client->sioc)); 2707 client->ioc = QIO_CHANNEL(sioc); 2708 object_ref(OBJECT(client->ioc)); 2709 client->close_fn = close_fn; 2710 2711 co = qemu_coroutine_create(nbd_co_client_start, client); 2712 qemu_coroutine_enter(co); 2713 } 2714