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_DIRTY_BITMAP 1 31 32 /* 33 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical 34 * constant. If an increase is needed, note that the NBD protocol 35 * recommends no larger than 32 mb, so that the client won't consider 36 * the reply as a denial of service attack. 37 */ 38 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) 39 40 static int system_errno_to_nbd_errno(int err) 41 { 42 switch (err) { 43 case 0: 44 return NBD_SUCCESS; 45 case EPERM: 46 case EROFS: 47 return NBD_EPERM; 48 case EIO: 49 return NBD_EIO; 50 case ENOMEM: 51 return NBD_ENOMEM; 52 #ifdef EDQUOT 53 case EDQUOT: 54 #endif 55 case EFBIG: 56 case ENOSPC: 57 return NBD_ENOSPC; 58 case EOVERFLOW: 59 return NBD_EOVERFLOW; 60 case ENOTSUP: 61 #if ENOTSUP != EOPNOTSUPP 62 case EOPNOTSUPP: 63 #endif 64 return NBD_ENOTSUP; 65 case ESHUTDOWN: 66 return NBD_ESHUTDOWN; 67 case EINVAL: 68 default: 69 return NBD_EINVAL; 70 } 71 } 72 73 /* Definitions for opaque data types */ 74 75 typedef struct NBDRequestData NBDRequestData; 76 77 struct NBDRequestData { 78 QSIMPLEQ_ENTRY(NBDRequestData) entry; 79 NBDClient *client; 80 uint8_t *data; 81 bool complete; 82 }; 83 84 struct NBDExport { 85 BlockExport common; 86 87 char *name; 88 char *description; 89 uint64_t size; 90 uint16_t nbdflags; 91 QTAILQ_HEAD(, NBDClient) clients; 92 QTAILQ_ENTRY(NBDExport) next; 93 94 BlockBackend *eject_notifier_blk; 95 Notifier eject_notifier; 96 97 BdrvDirtyBitmap *export_bitmap; 98 char *export_bitmap_context; 99 }; 100 101 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 102 103 /* NBDExportMetaContexts represents a list of contexts to be exported, 104 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 105 * NBD_OPT_LIST_META_CONTEXT. */ 106 typedef struct NBDExportMetaContexts { 107 NBDExport *exp; 108 bool valid; /* means that negotiation of the option finished without 109 errors */ 110 bool base_allocation; /* export base:allocation context (block status) */ 111 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */ 112 } NBDExportMetaContexts; 113 114 struct NBDClient { 115 int refcount; 116 void (*close_fn)(NBDClient *client, bool negotiated); 117 118 NBDExport *exp; 119 QCryptoTLSCreds *tlscreds; 120 char *tlsauthz; 121 QIOChannelSocket *sioc; /* The underlying data channel */ 122 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 123 124 Coroutine *recv_coroutine; 125 126 CoMutex send_lock; 127 Coroutine *send_coroutine; 128 129 QTAILQ_ENTRY(NBDClient) next; 130 int nb_requests; 131 bool closing; 132 133 uint32_t check_align; /* If non-zero, check for aligned client requests */ 134 135 bool structured_reply; 136 NBDExportMetaContexts export_meta; 137 138 uint32_t opt; /* Current option being negotiated */ 139 uint32_t optlen; /* remaining length of data in ioc for the option being 140 negotiated now */ 141 }; 142 143 static void nbd_client_receive_next_request(NBDClient *client); 144 145 /* Basic flow for negotiation 146 147 Server Client 148 Negotiate 149 150 or 151 152 Server Client 153 Negotiate #1 154 Option 155 Negotiate #2 156 157 ---- 158 159 followed by 160 161 Server Client 162 Request 163 Response 164 Request 165 Response 166 ... 167 ... 168 Request (type == 2) 169 170 */ 171 172 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 173 uint32_t type, uint32_t length) 174 { 175 stq_be_p(&rep->magic, NBD_REP_MAGIC); 176 stl_be_p(&rep->option, option); 177 stl_be_p(&rep->type, type); 178 stl_be_p(&rep->length, length); 179 } 180 181 /* Send a reply header, including length, but no payload. 182 * Return -errno on error, 0 on success. */ 183 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 184 uint32_t len, Error **errp) 185 { 186 NBDOptionReply rep; 187 188 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 189 type, nbd_rep_lookup(type), len); 190 191 assert(len < NBD_MAX_BUFFER_SIZE); 192 193 set_be_option_rep(&rep, client->opt, type, len); 194 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 195 } 196 197 /* Send a reply header with default 0 length. 198 * Return -errno on error, 0 on success. */ 199 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 200 Error **errp) 201 { 202 return nbd_negotiate_send_rep_len(client, type, 0, errp); 203 } 204 205 /* Send an error reply. 206 * Return -errno on error, 0 on success. */ 207 static int GCC_FMT_ATTR(4, 0) 208 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 209 Error **errp, const char *fmt, va_list va) 210 { 211 ERRP_GUARD(); 212 g_autofree char *msg = NULL; 213 int ret; 214 size_t len; 215 216 msg = g_strdup_vprintf(fmt, va); 217 len = strlen(msg); 218 assert(len < NBD_MAX_STRING_SIZE); 219 trace_nbd_negotiate_send_rep_err(msg); 220 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 221 if (ret < 0) { 222 return ret; 223 } 224 if (nbd_write(client->ioc, msg, len, errp) < 0) { 225 error_prepend(errp, "write failed (error message): "); 226 return -EIO; 227 } 228 229 return 0; 230 } 231 232 /* 233 * Return a malloc'd copy of @name suitable for use in an error reply. 234 */ 235 static char * 236 nbd_sanitize_name(const char *name) 237 { 238 if (strnlen(name, 80) < 80) { 239 return g_strdup(name); 240 } 241 /* XXX Should we also try to sanitize any control characters? */ 242 return g_strdup_printf("%.80s...", name); 243 } 244 245 /* Send an error reply. 246 * Return -errno on error, 0 on success. */ 247 static int GCC_FMT_ATTR(4, 5) 248 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 249 Error **errp, const char *fmt, ...) 250 { 251 va_list va; 252 int ret; 253 254 va_start(va, fmt); 255 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 256 va_end(va); 257 return ret; 258 } 259 260 /* Drop remainder of the current option, and send a reply with the 261 * given error type and message. Return -errno on read or write 262 * failure; or 0 if connection is still live. */ 263 static int GCC_FMT_ATTR(4, 0) 264 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 265 const char *fmt, va_list va) 266 { 267 int ret = nbd_drop(client->ioc, client->optlen, errp); 268 269 client->optlen = 0; 270 if (!ret) { 271 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 272 } 273 return ret; 274 } 275 276 static int GCC_FMT_ATTR(4, 5) 277 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 278 const char *fmt, ...) 279 { 280 int ret; 281 va_list va; 282 283 va_start(va, fmt); 284 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 285 va_end(va); 286 287 return ret; 288 } 289 290 static int GCC_FMT_ATTR(3, 4) 291 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 292 { 293 int ret; 294 va_list va; 295 296 va_start(va, fmt); 297 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 298 va_end(va); 299 300 return ret; 301 } 302 303 /* Read size bytes from the unparsed payload of the current option. 304 * If @check_nul, require that no NUL bytes appear in buffer. 305 * Return -errno on I/O error, 0 if option was completely handled by 306 * sending a reply about inconsistent lengths, or 1 on success. */ 307 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 308 bool check_nul, Error **errp) 309 { 310 if (size > client->optlen) { 311 return nbd_opt_invalid(client, errp, 312 "Inconsistent lengths in option %s", 313 nbd_opt_lookup(client->opt)); 314 } 315 client->optlen -= size; 316 if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) { 317 return -EIO; 318 } 319 320 if (check_nul && strnlen(buffer, size) != size) { 321 return nbd_opt_invalid(client, errp, 322 "Unexpected embedded NUL in option %s", 323 nbd_opt_lookup(client->opt)); 324 } 325 return 1; 326 } 327 328 /* Drop size bytes from the unparsed payload of the current option. 329 * Return -errno on I/O error, 0 if option was completely handled by 330 * sending a reply about inconsistent lengths, or 1 on success. */ 331 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 332 { 333 if (size > client->optlen) { 334 return nbd_opt_invalid(client, errp, 335 "Inconsistent lengths in option %s", 336 nbd_opt_lookup(client->opt)); 337 } 338 client->optlen -= size; 339 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 340 } 341 342 /* nbd_opt_read_name 343 * 344 * Read a string with the format: 345 * uint32_t len (<= NBD_MAX_STRING_SIZE) 346 * len bytes string (not 0-terminated) 347 * 348 * On success, @name will be allocated. 349 * If @length is non-null, it will be set to the actual string length. 350 * 351 * Return -errno on I/O error, 0 if option was completely handled by 352 * sending a reply about inconsistent lengths, or 1 on success. 353 */ 354 static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length, 355 Error **errp) 356 { 357 int ret; 358 uint32_t len; 359 g_autofree char *local_name = NULL; 360 361 *name = NULL; 362 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 363 if (ret <= 0) { 364 return ret; 365 } 366 len = cpu_to_be32(len); 367 368 if (len > NBD_MAX_STRING_SIZE) { 369 return nbd_opt_invalid(client, errp, 370 "Invalid name length: %" PRIu32, len); 371 } 372 373 local_name = g_malloc(len + 1); 374 ret = nbd_opt_read(client, local_name, len, true, errp); 375 if (ret <= 0) { 376 return ret; 377 } 378 local_name[len] = '\0'; 379 380 if (length) { 381 *length = len; 382 } 383 *name = g_steal_pointer(&local_name); 384 385 return 1; 386 } 387 388 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 389 * Return -errno on error, 0 on success. */ 390 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 391 Error **errp) 392 { 393 ERRP_GUARD(); 394 size_t name_len, desc_len; 395 uint32_t len; 396 const char *name = exp->name ? exp->name : ""; 397 const char *desc = exp->description ? exp->description : ""; 398 QIOChannel *ioc = client->ioc; 399 int ret; 400 401 trace_nbd_negotiate_send_rep_list(name, desc); 402 name_len = strlen(name); 403 desc_len = strlen(desc); 404 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE); 405 len = name_len + desc_len + sizeof(len); 406 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 407 if (ret < 0) { 408 return ret; 409 } 410 411 len = cpu_to_be32(name_len); 412 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 413 error_prepend(errp, "write failed (name length): "); 414 return -EINVAL; 415 } 416 417 if (nbd_write(ioc, name, name_len, errp) < 0) { 418 error_prepend(errp, "write failed (name buffer): "); 419 return -EINVAL; 420 } 421 422 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 423 error_prepend(errp, "write failed (description buffer): "); 424 return -EINVAL; 425 } 426 427 return 0; 428 } 429 430 /* Process the NBD_OPT_LIST command, with a potential series of replies. 431 * Return -errno on error, 0 on success. */ 432 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 433 { 434 NBDExport *exp; 435 assert(client->opt == NBD_OPT_LIST); 436 437 /* For each export, send a NBD_REP_SERVER reply. */ 438 QTAILQ_FOREACH(exp, &exports, next) { 439 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 440 return -EINVAL; 441 } 442 } 443 /* Finish with a NBD_REP_ACK. */ 444 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 445 } 446 447 static void nbd_check_meta_export(NBDClient *client) 448 { 449 client->export_meta.valid &= client->exp == client->export_meta.exp; 450 } 451 452 /* Send a reply to NBD_OPT_EXPORT_NAME. 453 * Return -errno on error, 0 on success. */ 454 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, 455 Error **errp) 456 { 457 ERRP_GUARD(); 458 g_autofree char *name = NULL; 459 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 460 size_t len; 461 int ret; 462 uint16_t myflags; 463 464 /* Client sends: 465 [20 .. xx] export name (length bytes) 466 Server replies: 467 [ 0 .. 7] size 468 [ 8 .. 9] export flags 469 [10 .. 133] reserved (0) [unless no_zeroes] 470 */ 471 trace_nbd_negotiate_handle_export_name(); 472 if (client->optlen > NBD_MAX_STRING_SIZE) { 473 error_setg(errp, "Bad length received"); 474 return -EINVAL; 475 } 476 name = g_malloc(client->optlen + 1); 477 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 478 return -EIO; 479 } 480 name[client->optlen] = '\0'; 481 client->optlen = 0; 482 483 trace_nbd_negotiate_handle_export_name_request(name); 484 485 client->exp = nbd_export_find(name); 486 if (!client->exp) { 487 error_setg(errp, "export not found"); 488 return -EINVAL; 489 } 490 491 myflags = client->exp->nbdflags; 492 if (client->structured_reply) { 493 myflags |= NBD_FLAG_SEND_DF; 494 } 495 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags); 496 stq_be_p(buf, client->exp->size); 497 stw_be_p(buf + 8, myflags); 498 len = no_zeroes ? 10 : sizeof(buf); 499 ret = nbd_write(client->ioc, buf, len, errp); 500 if (ret < 0) { 501 error_prepend(errp, "write failed: "); 502 return ret; 503 } 504 505 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 506 blk_exp_ref(&client->exp->common); 507 nbd_check_meta_export(client); 508 509 return 0; 510 } 511 512 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 513 * The buffer does NOT include the info type prefix. 514 * Return -errno on error, 0 if ready to send more. */ 515 static int nbd_negotiate_send_info(NBDClient *client, 516 uint16_t info, uint32_t length, void *buf, 517 Error **errp) 518 { 519 int rc; 520 521 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 522 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 523 sizeof(info) + length, errp); 524 if (rc < 0) { 525 return rc; 526 } 527 info = cpu_to_be16(info); 528 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 529 return -EIO; 530 } 531 if (nbd_write(client->ioc, buf, length, errp) < 0) { 532 return -EIO; 533 } 534 return 0; 535 } 536 537 /* nbd_reject_length: Handle any unexpected payload. 538 * @fatal requests that we quit talking to the client, even if we are able 539 * to successfully send an error reply. 540 * Return: 541 * -errno transmission error occurred or @fatal was requested, errp is set 542 * 0 error message successfully sent to client, errp is not set 543 */ 544 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 545 { 546 int ret; 547 548 assert(client->optlen); 549 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 550 nbd_opt_lookup(client->opt)); 551 if (fatal && !ret) { 552 error_setg(errp, "option '%s' has unexpected length", 553 nbd_opt_lookup(client->opt)); 554 return -EINVAL; 555 } 556 return ret; 557 } 558 559 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 560 * Return -errno on error, 0 if ready for next option, and 1 to move 561 * into transmission phase. */ 562 static int nbd_negotiate_handle_info(NBDClient *client, Error **errp) 563 { 564 int rc; 565 g_autofree char *name = NULL; 566 NBDExport *exp; 567 uint16_t requests; 568 uint16_t request; 569 uint32_t namelen = 0; 570 bool sendname = false; 571 bool blocksize = false; 572 uint32_t sizes[3]; 573 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 574 uint32_t check_align = 0; 575 uint16_t myflags; 576 577 /* Client sends: 578 4 bytes: L, name length (can be 0) 579 L bytes: export name 580 2 bytes: N, number of requests (can be 0) 581 N * 2 bytes: N requests 582 */ 583 rc = nbd_opt_read_name(client, &name, &namelen, errp); 584 if (rc <= 0) { 585 return rc; 586 } 587 trace_nbd_negotiate_handle_export_name_request(name); 588 589 rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp); 590 if (rc <= 0) { 591 return rc; 592 } 593 requests = be16_to_cpu(requests); 594 trace_nbd_negotiate_handle_info_requests(requests); 595 while (requests--) { 596 rc = nbd_opt_read(client, &request, sizeof(request), false, errp); 597 if (rc <= 0) { 598 return rc; 599 } 600 request = be16_to_cpu(request); 601 trace_nbd_negotiate_handle_info_request(request, 602 nbd_info_lookup(request)); 603 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 604 * everything else is either a request we don't know or 605 * something we send regardless of request */ 606 switch (request) { 607 case NBD_INFO_NAME: 608 sendname = true; 609 break; 610 case NBD_INFO_BLOCK_SIZE: 611 blocksize = true; 612 break; 613 } 614 } 615 if (client->optlen) { 616 return nbd_reject_length(client, false, errp); 617 } 618 619 exp = nbd_export_find(name); 620 if (!exp) { 621 g_autofree char *sane_name = nbd_sanitize_name(name); 622 623 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 624 errp, "export '%s' not present", 625 sane_name); 626 } 627 628 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 629 if (sendname) { 630 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 631 errp); 632 if (rc < 0) { 633 return rc; 634 } 635 } 636 637 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 638 * client request */ 639 if (exp->description) { 640 size_t len = strlen(exp->description); 641 642 assert(len <= NBD_MAX_STRING_SIZE); 643 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 644 len, exp->description, errp); 645 if (rc < 0) { 646 return rc; 647 } 648 } 649 650 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 651 * according to whether the client requested it, and according to 652 * whether this is OPT_INFO or OPT_GO. */ 653 /* minimum - 1 for back-compat, or actual if client will obey it. */ 654 if (client->opt == NBD_OPT_INFO || blocksize) { 655 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk); 656 } else { 657 sizes[0] = 1; 658 } 659 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 660 /* preferred - Hard-code to 4096 for now. 661 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 662 sizes[1] = MAX(4096, sizes[0]); 663 /* maximum - At most 32M, but smaller as appropriate. */ 664 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE); 665 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 666 sizes[0] = cpu_to_be32(sizes[0]); 667 sizes[1] = cpu_to_be32(sizes[1]); 668 sizes[2] = cpu_to_be32(sizes[2]); 669 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 670 sizeof(sizes), sizes, errp); 671 if (rc < 0) { 672 return rc; 673 } 674 675 /* Send NBD_INFO_EXPORT always */ 676 myflags = exp->nbdflags; 677 if (client->structured_reply) { 678 myflags |= NBD_FLAG_SEND_DF; 679 } 680 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags); 681 stq_be_p(buf, exp->size); 682 stw_be_p(buf + 8, myflags); 683 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 684 sizeof(buf), buf, errp); 685 if (rc < 0) { 686 return rc; 687 } 688 689 /* 690 * If the client is just asking for NBD_OPT_INFO, but forgot to 691 * request block sizes in a situation that would impact 692 * performance, then return an error. But for NBD_OPT_GO, we 693 * tolerate all clients, regardless of alignments. 694 */ 695 if (client->opt == NBD_OPT_INFO && !blocksize && 696 blk_get_request_alignment(exp->common.blk) > 1) { 697 return nbd_negotiate_send_rep_err(client, 698 NBD_REP_ERR_BLOCK_SIZE_REQD, 699 errp, 700 "request NBD_INFO_BLOCK_SIZE to " 701 "use this export"); 702 } 703 704 /* Final reply */ 705 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 706 if (rc < 0) { 707 return rc; 708 } 709 710 if (client->opt == NBD_OPT_GO) { 711 client->exp = exp; 712 client->check_align = check_align; 713 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 714 blk_exp_ref(&client->exp->common); 715 nbd_check_meta_export(client); 716 rc = 1; 717 } 718 return rc; 719 } 720 721 722 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 723 * new channel for all further (now-encrypted) communication. */ 724 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 725 Error **errp) 726 { 727 QIOChannel *ioc; 728 QIOChannelTLS *tioc; 729 struct NBDTLSHandshakeData data = { 0 }; 730 731 assert(client->opt == NBD_OPT_STARTTLS); 732 733 trace_nbd_negotiate_handle_starttls(); 734 ioc = client->ioc; 735 736 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 737 return NULL; 738 } 739 740 tioc = qio_channel_tls_new_server(ioc, 741 client->tlscreds, 742 client->tlsauthz, 743 errp); 744 if (!tioc) { 745 return NULL; 746 } 747 748 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 749 trace_nbd_negotiate_handle_starttls_handshake(); 750 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 751 qio_channel_tls_handshake(tioc, 752 nbd_tls_handshake, 753 &data, 754 NULL, 755 NULL); 756 757 if (!data.complete) { 758 g_main_loop_run(data.loop); 759 } 760 g_main_loop_unref(data.loop); 761 if (data.error) { 762 object_unref(OBJECT(tioc)); 763 error_propagate(errp, data.error); 764 return NULL; 765 } 766 767 return QIO_CHANNEL(tioc); 768 } 769 770 /* nbd_negotiate_send_meta_context 771 * 772 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 773 * 774 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 775 */ 776 static int nbd_negotiate_send_meta_context(NBDClient *client, 777 const char *context, 778 uint32_t context_id, 779 Error **errp) 780 { 781 NBDOptionReplyMetaContext opt; 782 struct iovec iov[] = { 783 {.iov_base = &opt, .iov_len = sizeof(opt)}, 784 {.iov_base = (void *)context, .iov_len = strlen(context)} 785 }; 786 787 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE); 788 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 789 context_id = 0; 790 } 791 792 trace_nbd_negotiate_meta_query_reply(context, context_id); 793 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 794 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 795 stl_be_p(&opt.context_id, context_id); 796 797 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 798 } 799 800 /* 801 * Return true if @query matches @pattern, or if @query is empty when 802 * the @client is performing _LIST_. 803 */ 804 static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 805 const char *query) 806 { 807 if (!*query) { 808 trace_nbd_negotiate_meta_query_parse("empty"); 809 return client->opt == NBD_OPT_LIST_META_CONTEXT; 810 } 811 if (strcmp(query, pattern) == 0) { 812 trace_nbd_negotiate_meta_query_parse(pattern); 813 return true; 814 } 815 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 816 return false; 817 } 818 819 /* 820 * Return true and adjust @str in place if it begins with @prefix. 821 */ 822 static bool nbd_strshift(const char **str, const char *prefix) 823 { 824 size_t len = strlen(prefix); 825 826 if (strncmp(*str, prefix, len) == 0) { 827 *str += len; 828 return true; 829 } 830 return false; 831 } 832 833 /* nbd_meta_base_query 834 * 835 * Handle queries to 'base' namespace. For now, only the base:allocation 836 * context is available. Return true if @query has been handled. 837 */ 838 static bool nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 839 const char *query) 840 { 841 if (!nbd_strshift(&query, "base:")) { 842 return false; 843 } 844 trace_nbd_negotiate_meta_query_parse("base:"); 845 846 if (nbd_meta_empty_or_pattern(client, "allocation", query)) { 847 meta->base_allocation = true; 848 } 849 return true; 850 } 851 852 /* nbd_meta_qemu_query 853 * 854 * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap: 855 * context is available. Return true if @query has been handled. 856 */ 857 static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 858 const char *query) 859 { 860 if (!nbd_strshift(&query, "qemu:")) { 861 return false; 862 } 863 trace_nbd_negotiate_meta_query_parse("qemu:"); 864 865 if (!*query) { 866 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 867 meta->bitmap = !!meta->exp->export_bitmap; 868 } 869 trace_nbd_negotiate_meta_query_parse("empty"); 870 return true; 871 } 872 873 if (nbd_strshift(&query, "dirty-bitmap:")) { 874 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 875 if (!meta->exp->export_bitmap) { 876 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported"); 877 return true; 878 } 879 if (nbd_meta_empty_or_pattern(client, 880 meta->exp->export_bitmap_context + 881 strlen("qemu:dirty-bitmap:"), query)) { 882 meta->bitmap = true; 883 } 884 return true; 885 } 886 887 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap"); 888 return true; 889 } 890 891 /* nbd_negotiate_meta_query 892 * 893 * Parse namespace name and call corresponding function to parse body of the 894 * query. 895 * 896 * The only supported namespaces are 'base' and 'qemu'. 897 * 898 * Return -errno on I/O error, 0 if option was completely handled by 899 * sending a reply about inconsistent lengths, or 1 on success. */ 900 static int nbd_negotiate_meta_query(NBDClient *client, 901 NBDExportMetaContexts *meta, Error **errp) 902 { 903 int ret; 904 g_autofree char *query = NULL; 905 uint32_t len; 906 907 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 908 if (ret <= 0) { 909 return ret; 910 } 911 len = cpu_to_be32(len); 912 913 if (len > NBD_MAX_STRING_SIZE) { 914 trace_nbd_negotiate_meta_query_skip("length too long"); 915 return nbd_opt_skip(client, len, errp); 916 } 917 918 query = g_malloc(len + 1); 919 ret = nbd_opt_read(client, query, len, true, errp); 920 if (ret <= 0) { 921 return ret; 922 } 923 query[len] = '\0'; 924 925 if (nbd_meta_base_query(client, meta, query)) { 926 return 1; 927 } 928 if (nbd_meta_qemu_query(client, meta, query)) { 929 return 1; 930 } 931 932 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 933 return 1; 934 } 935 936 /* nbd_negotiate_meta_queries 937 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 938 * 939 * Return -errno on I/O error, or 0 if option was completely handled. */ 940 static int nbd_negotiate_meta_queries(NBDClient *client, 941 NBDExportMetaContexts *meta, Error **errp) 942 { 943 int ret; 944 g_autofree char *export_name = NULL; 945 NBDExportMetaContexts local_meta; 946 uint32_t nb_queries; 947 int i; 948 949 if (!client->structured_reply) { 950 return nbd_opt_invalid(client, errp, 951 "request option '%s' when structured reply " 952 "is not negotiated", 953 nbd_opt_lookup(client->opt)); 954 } 955 956 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 957 /* Only change the caller's meta on SET. */ 958 meta = &local_meta; 959 } 960 961 memset(meta, 0, sizeof(*meta)); 962 963 ret = nbd_opt_read_name(client, &export_name, NULL, errp); 964 if (ret <= 0) { 965 return ret; 966 } 967 968 meta->exp = nbd_export_find(export_name); 969 if (meta->exp == NULL) { 970 g_autofree char *sane_name = nbd_sanitize_name(export_name); 971 972 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 973 "export '%s' not present", sane_name); 974 } 975 976 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp); 977 if (ret <= 0) { 978 return ret; 979 } 980 nb_queries = cpu_to_be32(nb_queries); 981 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 982 export_name, nb_queries); 983 984 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 985 /* enable all known contexts */ 986 meta->base_allocation = true; 987 meta->bitmap = !!meta->exp->export_bitmap; 988 } else { 989 for (i = 0; i < nb_queries; ++i) { 990 ret = nbd_negotiate_meta_query(client, meta, errp); 991 if (ret <= 0) { 992 return ret; 993 } 994 } 995 } 996 997 if (meta->base_allocation) { 998 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 999 NBD_META_ID_BASE_ALLOCATION, 1000 errp); 1001 if (ret < 0) { 1002 return ret; 1003 } 1004 } 1005 1006 if (meta->bitmap) { 1007 ret = nbd_negotiate_send_meta_context(client, 1008 meta->exp->export_bitmap_context, 1009 NBD_META_ID_DIRTY_BITMAP, 1010 errp); 1011 if (ret < 0) { 1012 return ret; 1013 } 1014 } 1015 1016 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1017 if (ret == 0) { 1018 meta->valid = true; 1019 } 1020 1021 return ret; 1022 } 1023 1024 /* nbd_negotiate_options 1025 * Process all NBD_OPT_* client option commands, during fixed newstyle 1026 * negotiation. 1027 * Return: 1028 * -errno on error, errp is set 1029 * 0 on successful negotiation, errp is not set 1030 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1031 * errp is not set 1032 */ 1033 static int nbd_negotiate_options(NBDClient *client, Error **errp) 1034 { 1035 uint32_t flags; 1036 bool fixedNewstyle = false; 1037 bool no_zeroes = false; 1038 1039 /* Client sends: 1040 [ 0 .. 3] client flags 1041 1042 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1043 [ 0 .. 7] NBD_OPTS_MAGIC 1044 [ 8 .. 11] NBD option 1045 [12 .. 15] Data length 1046 ... Rest of request 1047 1048 [ 0 .. 7] NBD_OPTS_MAGIC 1049 [ 8 .. 11] Second NBD option 1050 [12 .. 15] Data length 1051 ... Rest of request 1052 */ 1053 1054 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1055 return -EIO; 1056 } 1057 trace_nbd_negotiate_options_flags(flags); 1058 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1059 fixedNewstyle = true; 1060 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1061 } 1062 if (flags & NBD_FLAG_C_NO_ZEROES) { 1063 no_zeroes = true; 1064 flags &= ~NBD_FLAG_C_NO_ZEROES; 1065 } 1066 if (flags != 0) { 1067 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1068 return -EINVAL; 1069 } 1070 1071 while (1) { 1072 int ret; 1073 uint32_t option, length; 1074 uint64_t magic; 1075 1076 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1077 return -EINVAL; 1078 } 1079 trace_nbd_negotiate_options_check_magic(magic); 1080 if (magic != NBD_OPTS_MAGIC) { 1081 error_setg(errp, "Bad magic received"); 1082 return -EINVAL; 1083 } 1084 1085 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1086 return -EINVAL; 1087 } 1088 client->opt = option; 1089 1090 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1091 return -EINVAL; 1092 } 1093 assert(!client->optlen); 1094 client->optlen = length; 1095 1096 if (length > NBD_MAX_BUFFER_SIZE) { 1097 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1098 length, NBD_MAX_BUFFER_SIZE); 1099 return -EINVAL; 1100 } 1101 1102 trace_nbd_negotiate_options_check_option(option, 1103 nbd_opt_lookup(option)); 1104 if (client->tlscreds && 1105 client->ioc == (QIOChannel *)client->sioc) { 1106 QIOChannel *tioc; 1107 if (!fixedNewstyle) { 1108 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1109 return -EINVAL; 1110 } 1111 switch (option) { 1112 case NBD_OPT_STARTTLS: 1113 if (length) { 1114 /* Unconditionally drop the connection if the client 1115 * can't start a TLS negotiation correctly */ 1116 return nbd_reject_length(client, true, errp); 1117 } 1118 tioc = nbd_negotiate_handle_starttls(client, errp); 1119 if (!tioc) { 1120 return -EIO; 1121 } 1122 ret = 0; 1123 object_unref(OBJECT(client->ioc)); 1124 client->ioc = QIO_CHANNEL(tioc); 1125 break; 1126 1127 case NBD_OPT_EXPORT_NAME: 1128 /* No way to return an error to client, so drop connection */ 1129 error_setg(errp, "Option 0x%x not permitted before TLS", 1130 option); 1131 return -EINVAL; 1132 1133 default: 1134 /* Let the client keep trying, unless they asked to 1135 * quit. Always try to give an error back to the 1136 * client; but when replying to OPT_ABORT, be aware 1137 * that the client may hang up before receiving the 1138 * error, in which case we are fine ignoring the 1139 * resulting EPIPE. */ 1140 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1141 option == NBD_OPT_ABORT ? NULL : errp, 1142 "Option 0x%" PRIx32 1143 " not permitted before TLS", option); 1144 if (option == NBD_OPT_ABORT) { 1145 return 1; 1146 } 1147 break; 1148 } 1149 } else if (fixedNewstyle) { 1150 switch (option) { 1151 case NBD_OPT_LIST: 1152 if (length) { 1153 ret = nbd_reject_length(client, false, errp); 1154 } else { 1155 ret = nbd_negotiate_handle_list(client, errp); 1156 } 1157 break; 1158 1159 case NBD_OPT_ABORT: 1160 /* NBD spec says we must try to reply before 1161 * disconnecting, but that we must also tolerate 1162 * guests that don't wait for our reply. */ 1163 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1164 return 1; 1165 1166 case NBD_OPT_EXPORT_NAME: 1167 return nbd_negotiate_handle_export_name(client, no_zeroes, 1168 errp); 1169 1170 case NBD_OPT_INFO: 1171 case NBD_OPT_GO: 1172 ret = nbd_negotiate_handle_info(client, errp); 1173 if (ret == 1) { 1174 assert(option == NBD_OPT_GO); 1175 return 0; 1176 } 1177 break; 1178 1179 case NBD_OPT_STARTTLS: 1180 if (length) { 1181 ret = nbd_reject_length(client, false, errp); 1182 } else if (client->tlscreds) { 1183 ret = nbd_negotiate_send_rep_err(client, 1184 NBD_REP_ERR_INVALID, errp, 1185 "TLS already enabled"); 1186 } else { 1187 ret = nbd_negotiate_send_rep_err(client, 1188 NBD_REP_ERR_POLICY, errp, 1189 "TLS not configured"); 1190 } 1191 break; 1192 1193 case NBD_OPT_STRUCTURED_REPLY: 1194 if (length) { 1195 ret = nbd_reject_length(client, false, errp); 1196 } else if (client->structured_reply) { 1197 ret = nbd_negotiate_send_rep_err( 1198 client, NBD_REP_ERR_INVALID, errp, 1199 "structured reply already negotiated"); 1200 } else { 1201 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1202 client->structured_reply = true; 1203 } 1204 break; 1205 1206 case NBD_OPT_LIST_META_CONTEXT: 1207 case NBD_OPT_SET_META_CONTEXT: 1208 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1209 errp); 1210 break; 1211 1212 default: 1213 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1214 "Unsupported option %" PRIu32 " (%s)", 1215 option, nbd_opt_lookup(option)); 1216 break; 1217 } 1218 } else { 1219 /* 1220 * If broken new-style we should drop the connection 1221 * for anything except NBD_OPT_EXPORT_NAME 1222 */ 1223 switch (option) { 1224 case NBD_OPT_EXPORT_NAME: 1225 return nbd_negotiate_handle_export_name(client, no_zeroes, 1226 errp); 1227 1228 default: 1229 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1230 option, nbd_opt_lookup(option)); 1231 return -EINVAL; 1232 } 1233 } 1234 if (ret < 0) { 1235 return ret; 1236 } 1237 } 1238 } 1239 1240 /* nbd_negotiate 1241 * Return: 1242 * -errno on error, errp is set 1243 * 0 on successful negotiation, errp is not set 1244 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1245 * errp is not set 1246 */ 1247 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1248 { 1249 ERRP_GUARD(); 1250 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1251 int ret; 1252 1253 /* Old style negotiation header, no room for options 1254 [ 0 .. 7] passwd ("NBDMAGIC") 1255 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1256 [16 .. 23] size 1257 [24 .. 27] export flags (zero-extended) 1258 [28 .. 151] reserved (0) 1259 1260 New style negotiation header, client can send options 1261 [ 0 .. 7] passwd ("NBDMAGIC") 1262 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1263 [16 .. 17] server flags (0) 1264 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1265 */ 1266 1267 qio_channel_set_blocking(client->ioc, false, NULL); 1268 1269 trace_nbd_negotiate_begin(); 1270 memcpy(buf, "NBDMAGIC", 8); 1271 1272 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1273 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1274 1275 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1276 error_prepend(errp, "write failed: "); 1277 return -EINVAL; 1278 } 1279 ret = nbd_negotiate_options(client, errp); 1280 if (ret != 0) { 1281 if (ret < 0) { 1282 error_prepend(errp, "option negotiation failed: "); 1283 } 1284 return ret; 1285 } 1286 1287 /* Attach the channel to the same AioContext as the export */ 1288 if (client->exp && client->exp->common.ctx) { 1289 qio_channel_attach_aio_context(client->ioc, client->exp->common.ctx); 1290 } 1291 1292 assert(!client->optlen); 1293 trace_nbd_negotiate_success(); 1294 1295 return 0; 1296 } 1297 1298 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1299 Error **errp) 1300 { 1301 uint8_t buf[NBD_REQUEST_SIZE]; 1302 uint32_t magic; 1303 int ret; 1304 1305 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1306 if (ret < 0) { 1307 return ret; 1308 } 1309 1310 /* Request 1311 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1312 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1313 [ 6 .. 7] type (NBD_CMD_READ, ...) 1314 [ 8 .. 15] handle 1315 [16 .. 23] from 1316 [24 .. 27] len 1317 */ 1318 1319 magic = ldl_be_p(buf); 1320 request->flags = lduw_be_p(buf + 4); 1321 request->type = lduw_be_p(buf + 6); 1322 request->handle = ldq_be_p(buf + 8); 1323 request->from = ldq_be_p(buf + 16); 1324 request->len = ldl_be_p(buf + 24); 1325 1326 trace_nbd_receive_request(magic, request->flags, request->type, 1327 request->from, request->len); 1328 1329 if (magic != NBD_REQUEST_MAGIC) { 1330 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1331 return -EINVAL; 1332 } 1333 return 0; 1334 } 1335 1336 #define MAX_NBD_REQUESTS 16 1337 1338 void nbd_client_get(NBDClient *client) 1339 { 1340 client->refcount++; 1341 } 1342 1343 void nbd_client_put(NBDClient *client) 1344 { 1345 if (--client->refcount == 0) { 1346 /* The last reference should be dropped by client->close, 1347 * which is called by client_close. 1348 */ 1349 assert(client->closing); 1350 1351 qio_channel_detach_aio_context(client->ioc); 1352 object_unref(OBJECT(client->sioc)); 1353 object_unref(OBJECT(client->ioc)); 1354 if (client->tlscreds) { 1355 object_unref(OBJECT(client->tlscreds)); 1356 } 1357 g_free(client->tlsauthz); 1358 if (client->exp) { 1359 QTAILQ_REMOVE(&client->exp->clients, client, next); 1360 blk_exp_unref(&client->exp->common); 1361 } 1362 g_free(client); 1363 } 1364 } 1365 1366 static void client_close(NBDClient *client, bool negotiated) 1367 { 1368 if (client->closing) { 1369 return; 1370 } 1371 1372 client->closing = true; 1373 1374 /* Force requests to finish. They will drop their own references, 1375 * then we'll close the socket and free the NBDClient. 1376 */ 1377 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1378 NULL); 1379 1380 /* Also tell the client, so that they release their reference. */ 1381 if (client->close_fn) { 1382 client->close_fn(client, negotiated); 1383 } 1384 } 1385 1386 static NBDRequestData *nbd_request_get(NBDClient *client) 1387 { 1388 NBDRequestData *req; 1389 1390 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1391 client->nb_requests++; 1392 1393 req = g_new0(NBDRequestData, 1); 1394 nbd_client_get(client); 1395 req->client = client; 1396 return req; 1397 } 1398 1399 static void nbd_request_put(NBDRequestData *req) 1400 { 1401 NBDClient *client = req->client; 1402 1403 if (req->data) { 1404 qemu_vfree(req->data); 1405 } 1406 g_free(req); 1407 1408 client->nb_requests--; 1409 nbd_client_receive_next_request(client); 1410 1411 nbd_client_put(client); 1412 } 1413 1414 static void blk_aio_attached(AioContext *ctx, void *opaque) 1415 { 1416 NBDExport *exp = opaque; 1417 NBDClient *client; 1418 1419 trace_nbd_blk_aio_attached(exp->name, ctx); 1420 1421 exp->common.ctx = ctx; 1422 1423 QTAILQ_FOREACH(client, &exp->clients, next) { 1424 qio_channel_attach_aio_context(client->ioc, ctx); 1425 if (client->recv_coroutine) { 1426 aio_co_schedule(ctx, client->recv_coroutine); 1427 } 1428 if (client->send_coroutine) { 1429 aio_co_schedule(ctx, client->send_coroutine); 1430 } 1431 } 1432 } 1433 1434 static void blk_aio_detach(void *opaque) 1435 { 1436 NBDExport *exp = opaque; 1437 NBDClient *client; 1438 1439 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx); 1440 1441 QTAILQ_FOREACH(client, &exp->clients, next) { 1442 qio_channel_detach_aio_context(client->ioc); 1443 } 1444 1445 exp->common.ctx = NULL; 1446 } 1447 1448 static void nbd_eject_notifier(Notifier *n, void *data) 1449 { 1450 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1451 1452 blk_exp_request_shutdown(&exp->common); 1453 } 1454 1455 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) 1456 { 1457 NBDExport *nbd_exp = container_of(exp, NBDExport, common); 1458 assert(exp->drv == &blk_exp_nbd); 1459 assert(nbd_exp->eject_notifier_blk == NULL); 1460 1461 blk_ref(blk); 1462 nbd_exp->eject_notifier_blk = blk; 1463 nbd_exp->eject_notifier.notify = nbd_eject_notifier; 1464 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier); 1465 } 1466 1467 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, 1468 Error **errp) 1469 { 1470 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1471 BlockExportOptionsNbd *arg = &exp_args->u.nbd; 1472 BlockBackend *blk = blk_exp->blk; 1473 int64_t size; 1474 uint64_t perm, shared_perm; 1475 bool readonly = !exp_args->writable; 1476 bool shared = !exp_args->writable; 1477 int ret; 1478 1479 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); 1480 1481 if (!nbd_server_is_running()) { 1482 error_setg(errp, "NBD server not running"); 1483 return -EINVAL; 1484 } 1485 1486 if (!arg->has_name) { 1487 arg->name = exp_args->node_name; 1488 } 1489 1490 if (strlen(arg->name) > NBD_MAX_STRING_SIZE) { 1491 error_setg(errp, "export name '%s' too long", arg->name); 1492 return -EINVAL; 1493 } 1494 1495 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) { 1496 error_setg(errp, "description '%s' too long", arg->description); 1497 return -EINVAL; 1498 } 1499 1500 if (nbd_export_find(arg->name)) { 1501 error_setg(errp, "NBD server already has export named '%s'", arg->name); 1502 return -EEXIST; 1503 } 1504 1505 size = blk_getlength(blk); 1506 if (size < 0) { 1507 error_setg_errno(errp, -size, 1508 "Failed to determine the NBD export's length"); 1509 return size; 1510 } 1511 1512 /* Don't allow resize while the NBD server is running, otherwise we don't 1513 * care what happens with the node. */ 1514 blk_get_perm(blk, &perm, &shared_perm); 1515 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); 1516 if (ret < 0) { 1517 return ret; 1518 } 1519 1520 blk_set_allow_aio_context_change(blk, true); 1521 1522 QTAILQ_INIT(&exp->clients); 1523 exp->name = g_strdup(arg->name); 1524 exp->description = g_strdup(arg->description); 1525 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1526 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1527 if (readonly) { 1528 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1529 if (shared) { 1530 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1531 } 1532 } else { 1533 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1534 NBD_FLAG_SEND_FAST_ZERO); 1535 } 1536 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1537 1538 if (arg->bitmap) { 1539 BlockDriverState *bs = blk_bs(blk); 1540 BdrvDirtyBitmap *bm = NULL; 1541 1542 while (bs) { 1543 bm = bdrv_find_dirty_bitmap(bs, arg->bitmap); 1544 if (bm != NULL) { 1545 break; 1546 } 1547 1548 bs = bdrv_filter_or_cow_bs(bs); 1549 } 1550 1551 if (bm == NULL) { 1552 ret = -ENOENT; 1553 error_setg(errp, "Bitmap '%s' is not found", arg->bitmap); 1554 goto fail; 1555 } 1556 1557 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1558 ret = -EINVAL; 1559 goto fail; 1560 } 1561 1562 if (readonly && bdrv_is_writable(bs) && 1563 bdrv_dirty_bitmap_enabled(bm)) { 1564 ret = -EINVAL; 1565 error_setg(errp, 1566 "Enabled bitmap '%s' incompatible with readonly export", 1567 arg->bitmap); 1568 goto fail; 1569 } 1570 1571 bdrv_dirty_bitmap_set_busy(bm, true); 1572 exp->export_bitmap = bm; 1573 assert(strlen(arg->bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE); 1574 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s", 1575 arg->bitmap); 1576 assert(strlen(exp->export_bitmap_context) < NBD_MAX_STRING_SIZE); 1577 } 1578 1579 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1580 1581 QTAILQ_INSERT_TAIL(&exports, exp, next); 1582 1583 return 0; 1584 1585 fail: 1586 g_free(exp->name); 1587 g_free(exp->description); 1588 return ret; 1589 } 1590 1591 NBDExport *nbd_export_find(const char *name) 1592 { 1593 NBDExport *exp; 1594 QTAILQ_FOREACH(exp, &exports, next) { 1595 if (strcmp(name, exp->name) == 0) { 1596 return exp; 1597 } 1598 } 1599 1600 return NULL; 1601 } 1602 1603 AioContext * 1604 nbd_export_aio_context(NBDExport *exp) 1605 { 1606 return exp->common.ctx; 1607 } 1608 1609 static void nbd_export_request_shutdown(BlockExport *blk_exp) 1610 { 1611 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1612 NBDClient *client, *next; 1613 1614 blk_exp_ref(&exp->common); 1615 /* 1616 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1617 * close mode that stops advertising the export to new clients but 1618 * still permits existing clients to run to completion? Because of 1619 * that possibility, nbd_export_close() can be called more than 1620 * once on an export. 1621 */ 1622 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1623 client_close(client, true); 1624 } 1625 if (exp->name) { 1626 g_free(exp->name); 1627 exp->name = NULL; 1628 QTAILQ_REMOVE(&exports, exp, next); 1629 } 1630 blk_exp_unref(&exp->common); 1631 } 1632 1633 static void nbd_export_delete(BlockExport *blk_exp) 1634 { 1635 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1636 1637 assert(exp->name == NULL); 1638 assert(QTAILQ_EMPTY(&exp->clients)); 1639 1640 g_free(exp->description); 1641 exp->description = NULL; 1642 1643 if (exp->common.blk) { 1644 if (exp->eject_notifier_blk) { 1645 notifier_remove(&exp->eject_notifier); 1646 blk_unref(exp->eject_notifier_blk); 1647 } 1648 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached, 1649 blk_aio_detach, exp); 1650 } 1651 1652 if (exp->export_bitmap) { 1653 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); 1654 g_free(exp->export_bitmap_context); 1655 } 1656 } 1657 1658 const BlockExportDriver blk_exp_nbd = { 1659 .type = BLOCK_EXPORT_TYPE_NBD, 1660 .instance_size = sizeof(NBDExport), 1661 .create = nbd_export_create, 1662 .delete = nbd_export_delete, 1663 .request_shutdown = nbd_export_request_shutdown, 1664 }; 1665 1666 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1667 unsigned niov, Error **errp) 1668 { 1669 int ret; 1670 1671 g_assert(qemu_in_coroutine()); 1672 qemu_co_mutex_lock(&client->send_lock); 1673 client->send_coroutine = qemu_coroutine_self(); 1674 1675 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1676 1677 client->send_coroutine = NULL; 1678 qemu_co_mutex_unlock(&client->send_lock); 1679 1680 return ret; 1681 } 1682 1683 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1684 uint64_t handle) 1685 { 1686 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1687 stl_be_p(&reply->error, error); 1688 stq_be_p(&reply->handle, handle); 1689 } 1690 1691 static int nbd_co_send_simple_reply(NBDClient *client, 1692 uint64_t handle, 1693 uint32_t error, 1694 void *data, 1695 size_t len, 1696 Error **errp) 1697 { 1698 NBDSimpleReply reply; 1699 int nbd_err = system_errno_to_nbd_errno(error); 1700 struct iovec iov[] = { 1701 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1702 {.iov_base = data, .iov_len = len} 1703 }; 1704 1705 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1706 len); 1707 set_be_simple_reply(&reply, nbd_err, handle); 1708 1709 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1710 } 1711 1712 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1713 uint16_t type, uint64_t handle, uint32_t length) 1714 { 1715 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1716 stw_be_p(&chunk->flags, flags); 1717 stw_be_p(&chunk->type, type); 1718 stq_be_p(&chunk->handle, handle); 1719 stl_be_p(&chunk->length, length); 1720 } 1721 1722 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1723 uint64_t handle, 1724 Error **errp) 1725 { 1726 NBDStructuredReplyChunk chunk; 1727 struct iovec iov[] = { 1728 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1729 }; 1730 1731 trace_nbd_co_send_structured_done(handle); 1732 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1733 1734 return nbd_co_send_iov(client, iov, 1, errp); 1735 } 1736 1737 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1738 uint64_t handle, 1739 uint64_t offset, 1740 void *data, 1741 size_t size, 1742 bool final, 1743 Error **errp) 1744 { 1745 NBDStructuredReadData chunk; 1746 struct iovec iov[] = { 1747 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1748 {.iov_base = data, .iov_len = size} 1749 }; 1750 1751 assert(size); 1752 trace_nbd_co_send_structured_read(handle, offset, data, size); 1753 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1754 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1755 sizeof(chunk) - sizeof(chunk.h) + size); 1756 stq_be_p(&chunk.offset, offset); 1757 1758 return nbd_co_send_iov(client, iov, 2, errp); 1759 } 1760 1761 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1762 uint64_t handle, 1763 uint32_t error, 1764 const char *msg, 1765 Error **errp) 1766 { 1767 NBDStructuredError chunk; 1768 int nbd_err = system_errno_to_nbd_errno(error); 1769 struct iovec iov[] = { 1770 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1771 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1772 }; 1773 1774 assert(nbd_err); 1775 trace_nbd_co_send_structured_error(handle, nbd_err, 1776 nbd_err_lookup(nbd_err), msg ? msg : ""); 1777 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1778 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1779 stl_be_p(&chunk.error, nbd_err); 1780 stw_be_p(&chunk.message_length, iov[1].iov_len); 1781 1782 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1783 } 1784 1785 /* Do a sparse read and send the structured reply to the client. 1786 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1787 * reported to the client, at which point this function succeeds. 1788 */ 1789 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1790 uint64_t handle, 1791 uint64_t offset, 1792 uint8_t *data, 1793 size_t size, 1794 Error **errp) 1795 { 1796 int ret = 0; 1797 NBDExport *exp = client->exp; 1798 size_t progress = 0; 1799 1800 while (progress < size) { 1801 int64_t pnum; 1802 int status = bdrv_block_status_above(blk_bs(exp->common.blk), NULL, 1803 offset + progress, 1804 size - progress, &pnum, NULL, 1805 NULL); 1806 bool final; 1807 1808 if (status < 0) { 1809 char *msg = g_strdup_printf("unable to check for holes: %s", 1810 strerror(-status)); 1811 1812 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1813 errp); 1814 g_free(msg); 1815 return ret; 1816 } 1817 assert(pnum && pnum <= size - progress); 1818 final = progress + pnum == size; 1819 if (status & BDRV_BLOCK_ZERO) { 1820 NBDStructuredReadHole chunk; 1821 struct iovec iov[] = { 1822 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1823 }; 1824 1825 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1826 pnum); 1827 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1828 NBD_REPLY_TYPE_OFFSET_HOLE, 1829 handle, sizeof(chunk) - sizeof(chunk.h)); 1830 stq_be_p(&chunk.offset, offset + progress); 1831 stl_be_p(&chunk.length, pnum); 1832 ret = nbd_co_send_iov(client, iov, 1, errp); 1833 } else { 1834 ret = blk_pread(exp->common.blk, offset + progress, 1835 data + progress, pnum); 1836 if (ret < 0) { 1837 error_setg_errno(errp, -ret, "reading from file failed"); 1838 break; 1839 } 1840 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1841 data + progress, pnum, final, 1842 errp); 1843 } 1844 1845 if (ret < 0) { 1846 break; 1847 } 1848 progress += pnum; 1849 } 1850 return ret; 1851 } 1852 1853 typedef struct NBDExtentArray { 1854 NBDExtent *extents; 1855 unsigned int nb_alloc; 1856 unsigned int count; 1857 uint64_t total_length; 1858 bool can_add; 1859 bool converted_to_be; 1860 } NBDExtentArray; 1861 1862 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc) 1863 { 1864 NBDExtentArray *ea = g_new0(NBDExtentArray, 1); 1865 1866 ea->nb_alloc = nb_alloc; 1867 ea->extents = g_new(NBDExtent, nb_alloc); 1868 ea->can_add = true; 1869 1870 return ea; 1871 } 1872 1873 static void nbd_extent_array_free(NBDExtentArray *ea) 1874 { 1875 g_free(ea->extents); 1876 g_free(ea); 1877 } 1878 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free); 1879 1880 /* Further modifications of the array after conversion are abandoned */ 1881 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea) 1882 { 1883 int i; 1884 1885 assert(!ea->converted_to_be); 1886 ea->can_add = false; 1887 ea->converted_to_be = true; 1888 1889 for (i = 0; i < ea->count; i++) { 1890 ea->extents[i].flags = cpu_to_be32(ea->extents[i].flags); 1891 ea->extents[i].length = cpu_to_be32(ea->extents[i].length); 1892 } 1893 } 1894 1895 /* 1896 * Add extent to NBDExtentArray. If extent can't be added (no available space), 1897 * return -1. 1898 * For safety, when returning -1 for the first time, .can_add is set to false, 1899 * further call to nbd_extent_array_add() will crash. 1900 * (to avoid the situation, when after failing to add an extent (returned -1), 1901 * user miss this failure and add another extent, which is successfully added 1902 * (array is full, but new extent may be squashed into the last one), then we 1903 * have invalid array with skipped extent) 1904 */ 1905 static int nbd_extent_array_add(NBDExtentArray *ea, 1906 uint32_t length, uint32_t flags) 1907 { 1908 assert(ea->can_add); 1909 1910 if (!length) { 1911 return 0; 1912 } 1913 1914 /* Extend previous extent if flags are the same */ 1915 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) { 1916 uint64_t sum = (uint64_t)length + ea->extents[ea->count - 1].length; 1917 1918 if (sum <= UINT32_MAX) { 1919 ea->extents[ea->count - 1].length = sum; 1920 ea->total_length += length; 1921 return 0; 1922 } 1923 } 1924 1925 if (ea->count >= ea->nb_alloc) { 1926 ea->can_add = false; 1927 return -1; 1928 } 1929 1930 ea->total_length += length; 1931 ea->extents[ea->count] = (NBDExtent) {.length = length, .flags = flags}; 1932 ea->count++; 1933 1934 return 0; 1935 } 1936 1937 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 1938 uint64_t bytes, NBDExtentArray *ea) 1939 { 1940 while (bytes) { 1941 uint32_t flags; 1942 int64_t num; 1943 int ret = bdrv_block_status_above(bs, NULL, offset, bytes, &num, 1944 NULL, NULL); 1945 1946 if (ret < 0) { 1947 return ret; 1948 } 1949 1950 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 1951 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 1952 1953 if (nbd_extent_array_add(ea, num, flags) < 0) { 1954 return 0; 1955 } 1956 1957 offset += num; 1958 bytes -= num; 1959 } 1960 1961 return 0; 1962 } 1963 1964 /* 1965 * nbd_co_send_extents 1966 * 1967 * @ea is converted to BE by the function 1968 * @last controls whether NBD_REPLY_FLAG_DONE is sent. 1969 */ 1970 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 1971 NBDExtentArray *ea, 1972 bool last, uint32_t context_id, Error **errp) 1973 { 1974 NBDStructuredMeta chunk; 1975 struct iovec iov[] = { 1976 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1977 {.iov_base = ea->extents, .iov_len = ea->count * sizeof(ea->extents[0])} 1978 }; 1979 1980 nbd_extent_array_convert_to_be(ea); 1981 1982 trace_nbd_co_send_extents(handle, ea->count, context_id, ea->total_length, 1983 last); 1984 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 1985 NBD_REPLY_TYPE_BLOCK_STATUS, 1986 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1987 stl_be_p(&chunk.context_id, context_id); 1988 1989 return nbd_co_send_iov(client, iov, 2, errp); 1990 } 1991 1992 /* Get block status from the exported device and send it to the client */ 1993 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 1994 BlockDriverState *bs, uint64_t offset, 1995 uint32_t length, bool dont_fragment, 1996 bool last, uint32_t context_id, 1997 Error **errp) 1998 { 1999 int ret; 2000 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2001 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); 2002 2003 ret = blockstatus_to_extents(bs, offset, length, ea); 2004 if (ret < 0) { 2005 return nbd_co_send_structured_error( 2006 client, handle, -ret, "can't get block status", errp); 2007 } 2008 2009 return nbd_co_send_extents(client, handle, ea, last, context_id, errp); 2010 } 2011 2012 /* Populate @ea from a dirty bitmap. */ 2013 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap, 2014 uint64_t offset, uint64_t length, 2015 NBDExtentArray *es) 2016 { 2017 int64_t start, dirty_start, dirty_count; 2018 int64_t end = offset + length; 2019 bool full = false; 2020 2021 bdrv_dirty_bitmap_lock(bitmap); 2022 2023 for (start = offset; 2024 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX, 2025 &dirty_start, &dirty_count); 2026 start = dirty_start + dirty_count) 2027 { 2028 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) || 2029 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0)) 2030 { 2031 full = true; 2032 break; 2033 } 2034 } 2035 2036 if (!full) { 2037 /* last non dirty extent */ 2038 nbd_extent_array_add(es, end - start, 0); 2039 } 2040 2041 bdrv_dirty_bitmap_unlock(bitmap); 2042 } 2043 2044 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2045 BdrvDirtyBitmap *bitmap, uint64_t offset, 2046 uint32_t length, bool dont_fragment, bool last, 2047 uint32_t context_id, Error **errp) 2048 { 2049 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2050 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); 2051 2052 bitmap_to_extents(bitmap, offset, length, ea); 2053 2054 return nbd_co_send_extents(client, handle, ea, last, context_id, errp); 2055 } 2056 2057 /* nbd_co_receive_request 2058 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2059 * connection right away, and any other negative value to report an error to 2060 * the client (although the caller may still need to disconnect after reporting 2061 * the error). 2062 */ 2063 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2064 Error **errp) 2065 { 2066 NBDClient *client = req->client; 2067 int valid_flags; 2068 2069 g_assert(qemu_in_coroutine()); 2070 assert(client->recv_coroutine == qemu_coroutine_self()); 2071 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2072 return -EIO; 2073 } 2074 2075 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2076 nbd_cmd_lookup(request->type)); 2077 2078 if (request->type != NBD_CMD_WRITE) { 2079 /* No payload, we are ready to read the next request. */ 2080 req->complete = true; 2081 } 2082 2083 if (request->type == NBD_CMD_DISC) { 2084 /* Special case: we're going to disconnect without a reply, 2085 * whether or not flags, from, or len are bogus */ 2086 return -EIO; 2087 } 2088 2089 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2090 request->type == NBD_CMD_CACHE) 2091 { 2092 if (request->len > NBD_MAX_BUFFER_SIZE) { 2093 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2094 request->len, NBD_MAX_BUFFER_SIZE); 2095 return -EINVAL; 2096 } 2097 2098 if (request->type != NBD_CMD_CACHE) { 2099 req->data = blk_try_blockalign(client->exp->common.blk, 2100 request->len); 2101 if (req->data == NULL) { 2102 error_setg(errp, "No memory"); 2103 return -ENOMEM; 2104 } 2105 } 2106 } 2107 2108 if (request->type == NBD_CMD_WRITE) { 2109 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2110 errp) < 0) 2111 { 2112 return -EIO; 2113 } 2114 req->complete = true; 2115 2116 trace_nbd_co_receive_request_payload_received(request->handle, 2117 request->len); 2118 } 2119 2120 /* Sanity checks. */ 2121 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2122 (request->type == NBD_CMD_WRITE || 2123 request->type == NBD_CMD_WRITE_ZEROES || 2124 request->type == NBD_CMD_TRIM)) { 2125 error_setg(errp, "Export is read-only"); 2126 return -EROFS; 2127 } 2128 if (request->from > client->exp->size || 2129 request->len > client->exp->size - request->from) { 2130 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2131 ", Size: %" PRIu64, request->from, request->len, 2132 client->exp->size); 2133 return (request->type == NBD_CMD_WRITE || 2134 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2135 } 2136 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2137 client->check_align)) { 2138 /* 2139 * The block layer gracefully handles unaligned requests, but 2140 * it's still worth tracing client non-compliance 2141 */ 2142 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2143 request->from, 2144 request->len, 2145 client->check_align); 2146 } 2147 valid_flags = NBD_CMD_FLAG_FUA; 2148 if (request->type == NBD_CMD_READ && client->structured_reply) { 2149 valid_flags |= NBD_CMD_FLAG_DF; 2150 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2151 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2152 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2153 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2154 } 2155 if (request->flags & ~valid_flags) { 2156 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2157 nbd_cmd_lookup(request->type), request->flags); 2158 return -EINVAL; 2159 } 2160 2161 return 0; 2162 } 2163 2164 /* Send simple reply without a payload, or a structured error 2165 * @error_msg is ignored if @ret >= 0 2166 * Returns 0 if connection is still live, -errno on failure to talk to client 2167 */ 2168 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2169 uint64_t handle, 2170 int ret, 2171 const char *error_msg, 2172 Error **errp) 2173 { 2174 if (client->structured_reply && ret < 0) { 2175 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2176 errp); 2177 } else { 2178 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2179 NULL, 0, errp); 2180 } 2181 } 2182 2183 /* Handle NBD_CMD_READ request. 2184 * Return -errno if sending fails. Other errors are reported directly to the 2185 * client as an error reply. */ 2186 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2187 uint8_t *data, Error **errp) 2188 { 2189 int ret; 2190 NBDExport *exp = client->exp; 2191 2192 assert(request->type == NBD_CMD_READ); 2193 2194 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2195 if (request->flags & NBD_CMD_FLAG_FUA) { 2196 ret = blk_co_flush(exp->common.blk); 2197 if (ret < 0) { 2198 return nbd_send_generic_reply(client, request->handle, ret, 2199 "flush failed", errp); 2200 } 2201 } 2202 2203 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2204 request->len) 2205 { 2206 return nbd_co_send_sparse_read(client, request->handle, request->from, 2207 data, request->len, errp); 2208 } 2209 2210 ret = blk_pread(exp->common.blk, request->from, data, request->len); 2211 if (ret < 0) { 2212 return nbd_send_generic_reply(client, request->handle, ret, 2213 "reading from file failed", errp); 2214 } 2215 2216 if (client->structured_reply) { 2217 if (request->len) { 2218 return nbd_co_send_structured_read(client, request->handle, 2219 request->from, data, 2220 request->len, true, errp); 2221 } else { 2222 return nbd_co_send_structured_done(client, request->handle, errp); 2223 } 2224 } else { 2225 return nbd_co_send_simple_reply(client, request->handle, 0, 2226 data, request->len, errp); 2227 } 2228 } 2229 2230 /* 2231 * nbd_do_cmd_cache 2232 * 2233 * Handle NBD_CMD_CACHE request. 2234 * Return -errno if sending fails. Other errors are reported directly to the 2235 * client as an error reply. 2236 */ 2237 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2238 Error **errp) 2239 { 2240 int ret; 2241 NBDExport *exp = client->exp; 2242 2243 assert(request->type == NBD_CMD_CACHE); 2244 2245 ret = blk_co_preadv(exp->common.blk, request->from, request->len, 2246 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2247 2248 return nbd_send_generic_reply(client, request->handle, ret, 2249 "caching data failed", errp); 2250 } 2251 2252 /* Handle NBD request. 2253 * Return -errno if sending fails. Other errors are reported directly to the 2254 * client as an error reply. */ 2255 static coroutine_fn int nbd_handle_request(NBDClient *client, 2256 NBDRequest *request, 2257 uint8_t *data, Error **errp) 2258 { 2259 int ret; 2260 int flags; 2261 NBDExport *exp = client->exp; 2262 char *msg; 2263 2264 switch (request->type) { 2265 case NBD_CMD_CACHE: 2266 return nbd_do_cmd_cache(client, request, errp); 2267 2268 case NBD_CMD_READ: 2269 return nbd_do_cmd_read(client, request, data, errp); 2270 2271 case NBD_CMD_WRITE: 2272 flags = 0; 2273 if (request->flags & NBD_CMD_FLAG_FUA) { 2274 flags |= BDRV_REQ_FUA; 2275 } 2276 ret = blk_pwrite(exp->common.blk, request->from, data, request->len, 2277 flags); 2278 return nbd_send_generic_reply(client, request->handle, ret, 2279 "writing to file failed", errp); 2280 2281 case NBD_CMD_WRITE_ZEROES: 2282 flags = 0; 2283 if (request->flags & NBD_CMD_FLAG_FUA) { 2284 flags |= BDRV_REQ_FUA; 2285 } 2286 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2287 flags |= BDRV_REQ_MAY_UNMAP; 2288 } 2289 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2290 flags |= BDRV_REQ_NO_FALLBACK; 2291 } 2292 ret = 0; 2293 /* FIXME simplify this when blk_pwrite_zeroes switches to 64-bit */ 2294 while (ret >= 0 && request->len) { 2295 int align = client->check_align ?: 1; 2296 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, 2297 align)); 2298 ret = blk_pwrite_zeroes(exp->common.blk, request->from, len, flags); 2299 request->len -= len; 2300 request->from += len; 2301 } 2302 return nbd_send_generic_reply(client, request->handle, ret, 2303 "writing to file failed", errp); 2304 2305 case NBD_CMD_DISC: 2306 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2307 abort(); 2308 2309 case NBD_CMD_FLUSH: 2310 ret = blk_co_flush(exp->common.blk); 2311 return nbd_send_generic_reply(client, request->handle, ret, 2312 "flush failed", errp); 2313 2314 case NBD_CMD_TRIM: 2315 ret = 0; 2316 /* FIXME simplify this when blk_co_pdiscard switches to 64-bit */ 2317 while (ret >= 0 && request->len) { 2318 int align = client->check_align ?: 1; 2319 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, 2320 align)); 2321 ret = blk_co_pdiscard(exp->common.blk, request->from, len); 2322 request->len -= len; 2323 request->from += len; 2324 } 2325 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) { 2326 ret = blk_co_flush(exp->common.blk); 2327 } 2328 return nbd_send_generic_reply(client, request->handle, ret, 2329 "discard failed", errp); 2330 2331 case NBD_CMD_BLOCK_STATUS: 2332 if (!request->len) { 2333 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2334 "need non-zero length", errp); 2335 } 2336 if (client->export_meta.valid && 2337 (client->export_meta.base_allocation || 2338 client->export_meta.bitmap)) 2339 { 2340 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2341 2342 if (client->export_meta.base_allocation) { 2343 ret = nbd_co_send_block_status(client, request->handle, 2344 blk_bs(exp->common.blk), 2345 request->from, 2346 request->len, dont_fragment, 2347 !client->export_meta.bitmap, 2348 NBD_META_ID_BASE_ALLOCATION, 2349 errp); 2350 if (ret < 0) { 2351 return ret; 2352 } 2353 } 2354 2355 if (client->export_meta.bitmap) { 2356 ret = nbd_co_send_bitmap(client, request->handle, 2357 client->exp->export_bitmap, 2358 request->from, request->len, 2359 dont_fragment, 2360 true, NBD_META_ID_DIRTY_BITMAP, errp); 2361 if (ret < 0) { 2362 return ret; 2363 } 2364 } 2365 2366 return 0; 2367 } else { 2368 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2369 "CMD_BLOCK_STATUS not negotiated", 2370 errp); 2371 } 2372 2373 default: 2374 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2375 request->type); 2376 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2377 errp); 2378 g_free(msg); 2379 return ret; 2380 } 2381 } 2382 2383 /* Owns a reference to the NBDClient passed as opaque. */ 2384 static coroutine_fn void nbd_trip(void *opaque) 2385 { 2386 NBDClient *client = opaque; 2387 NBDRequestData *req; 2388 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2389 int ret; 2390 Error *local_err = NULL; 2391 2392 trace_nbd_trip(); 2393 if (client->closing) { 2394 nbd_client_put(client); 2395 return; 2396 } 2397 2398 req = nbd_request_get(client); 2399 ret = nbd_co_receive_request(req, &request, &local_err); 2400 client->recv_coroutine = NULL; 2401 2402 if (client->closing) { 2403 /* 2404 * The client may be closed when we are blocked in 2405 * nbd_co_receive_request() 2406 */ 2407 goto done; 2408 } 2409 2410 nbd_client_receive_next_request(client); 2411 if (ret == -EIO) { 2412 goto disconnect; 2413 } 2414 2415 if (ret < 0) { 2416 /* It wans't -EIO, so, according to nbd_co_receive_request() 2417 * semantics, we should return the error to the client. */ 2418 Error *export_err = local_err; 2419 2420 local_err = NULL; 2421 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2422 error_get_pretty(export_err), &local_err); 2423 error_free(export_err); 2424 } else { 2425 ret = nbd_handle_request(client, &request, req->data, &local_err); 2426 } 2427 if (ret < 0) { 2428 error_prepend(&local_err, "Failed to send reply: "); 2429 goto disconnect; 2430 } 2431 2432 /* We must disconnect after NBD_CMD_WRITE if we did not 2433 * read the payload. 2434 */ 2435 if (!req->complete) { 2436 error_setg(&local_err, "Request handling failed in intermediate state"); 2437 goto disconnect; 2438 } 2439 2440 done: 2441 nbd_request_put(req); 2442 nbd_client_put(client); 2443 return; 2444 2445 disconnect: 2446 if (local_err) { 2447 error_reportf_err(local_err, "Disconnect client, due to: "); 2448 } 2449 nbd_request_put(req); 2450 client_close(client, true); 2451 nbd_client_put(client); 2452 } 2453 2454 static void nbd_client_receive_next_request(NBDClient *client) 2455 { 2456 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2457 nbd_client_get(client); 2458 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2459 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine); 2460 } 2461 } 2462 2463 static coroutine_fn void nbd_co_client_start(void *opaque) 2464 { 2465 NBDClient *client = opaque; 2466 Error *local_err = NULL; 2467 2468 qemu_co_mutex_init(&client->send_lock); 2469 2470 if (nbd_negotiate(client, &local_err)) { 2471 if (local_err) { 2472 error_report_err(local_err); 2473 } 2474 client_close(client, false); 2475 return; 2476 } 2477 2478 nbd_client_receive_next_request(client); 2479 } 2480 2481 /* 2482 * Create a new client listener using the given channel @sioc. 2483 * Begin servicing it in a coroutine. When the connection closes, call 2484 * @close_fn with an indication of whether the client completed negotiation. 2485 */ 2486 void nbd_client_new(QIOChannelSocket *sioc, 2487 QCryptoTLSCreds *tlscreds, 2488 const char *tlsauthz, 2489 void (*close_fn)(NBDClient *, bool)) 2490 { 2491 NBDClient *client; 2492 Coroutine *co; 2493 2494 client = g_new0(NBDClient, 1); 2495 client->refcount = 1; 2496 client->tlscreds = tlscreds; 2497 if (tlscreds) { 2498 object_ref(OBJECT(client->tlscreds)); 2499 } 2500 client->tlsauthz = g_strdup(tlsauthz); 2501 client->sioc = sioc; 2502 object_ref(OBJECT(client->sioc)); 2503 client->ioc = QIO_CHANNEL(sioc); 2504 object_ref(OBJECT(client->ioc)); 2505 client->close_fn = close_fn; 2506 2507 co = qemu_coroutine_create(nbd_co_client_start, client); 2508 qemu_coroutine_enter(co); 2509 } 2510