1 /* 2 * Copyright Red Hat 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/block_int.h" 23 #include "block/export.h" 24 #include "block/dirty-bitmap.h" 25 #include "qapi/error.h" 26 #include "qemu/queue.h" 27 #include "trace.h" 28 #include "nbd-internal.h" 29 #include "qemu/units.h" 30 #include "qemu/memalign.h" 31 32 #define NBD_META_ID_BASE_ALLOCATION 0 33 #define NBD_META_ID_ALLOCATION_DEPTH 1 34 /* Dirty bitmaps use 'NBD_META_ID_DIRTY_BITMAP + i', so keep this id last. */ 35 #define NBD_META_ID_DIRTY_BITMAP 2 36 37 /* 38 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical 39 * constant. If an increase is needed, note that the NBD protocol 40 * recommends no larger than 32 mb, so that the client won't consider 41 * the reply as a denial of service attack. 42 */ 43 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) 44 45 static int system_errno_to_nbd_errno(int err) 46 { 47 switch (err) { 48 case 0: 49 return NBD_SUCCESS; 50 case EPERM: 51 case EROFS: 52 return NBD_EPERM; 53 case EIO: 54 return NBD_EIO; 55 case ENOMEM: 56 return NBD_ENOMEM; 57 #ifdef EDQUOT 58 case EDQUOT: 59 #endif 60 case EFBIG: 61 case ENOSPC: 62 return NBD_ENOSPC; 63 case EOVERFLOW: 64 return NBD_EOVERFLOW; 65 case ENOTSUP: 66 #if ENOTSUP != EOPNOTSUPP 67 case EOPNOTSUPP: 68 #endif 69 return NBD_ENOTSUP; 70 case ESHUTDOWN: 71 return NBD_ESHUTDOWN; 72 case EINVAL: 73 default: 74 return NBD_EINVAL; 75 } 76 } 77 78 /* Definitions for opaque data types */ 79 80 typedef struct NBDRequestData NBDRequestData; 81 82 struct NBDRequestData { 83 NBDClient *client; 84 uint8_t *data; 85 bool complete; 86 }; 87 88 struct NBDExport { 89 BlockExport common; 90 91 char *name; 92 char *description; 93 uint64_t size; 94 uint16_t nbdflags; 95 QTAILQ_HEAD(, NBDClient) clients; 96 QTAILQ_ENTRY(NBDExport) next; 97 98 BlockBackend *eject_notifier_blk; 99 Notifier eject_notifier; 100 101 bool allocation_depth; 102 BdrvDirtyBitmap **export_bitmaps; 103 size_t nr_export_bitmaps; 104 }; 105 106 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 107 108 /* 109 * NBDMetaContexts represents a list of meta contexts in use, 110 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 111 * NBD_OPT_LIST_META_CONTEXT. 112 */ 113 struct NBDMetaContexts { 114 const NBDExport *exp; /* associated export */ 115 size_t count; /* number of negotiated contexts */ 116 bool base_allocation; /* export base:allocation context (block status) */ 117 bool allocation_depth; /* export qemu:allocation-depth */ 118 bool *bitmaps; /* 119 * export qemu:dirty-bitmap:<export bitmap name>, 120 * sized by exp->nr_export_bitmaps 121 */ 122 }; 123 124 struct NBDClient { 125 int refcount; /* atomic */ 126 void (*close_fn)(NBDClient *client, bool negotiated); 127 128 QemuMutex lock; 129 130 NBDExport *exp; 131 QCryptoTLSCreds *tlscreds; 132 char *tlsauthz; 133 QIOChannelSocket *sioc; /* The underlying data channel */ 134 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 135 136 Coroutine *recv_coroutine; /* protected by lock */ 137 138 CoMutex send_lock; 139 Coroutine *send_coroutine; 140 141 bool read_yielding; /* protected by lock */ 142 bool quiescing; /* protected by lock */ 143 144 QTAILQ_ENTRY(NBDClient) next; 145 int nb_requests; /* protected by lock */ 146 bool closing; /* protected by lock */ 147 148 uint32_t check_align; /* If non-zero, check for aligned client requests */ 149 150 NBDMode mode; 151 NBDMetaContexts contexts; /* Negotiated meta contexts */ 152 153 uint32_t opt; /* Current option being negotiated */ 154 uint32_t optlen; /* remaining length of data in ioc for the option being 155 negotiated now */ 156 }; 157 158 static void nbd_client_receive_next_request(NBDClient *client); 159 160 /* Basic flow for negotiation 161 162 Server Client 163 Negotiate 164 165 or 166 167 Server Client 168 Negotiate #1 169 Option 170 Negotiate #2 171 172 ---- 173 174 followed by 175 176 Server Client 177 Request 178 Response 179 Request 180 Response 181 ... 182 ... 183 Request (type == 2) 184 185 */ 186 187 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 188 uint32_t type, uint32_t length) 189 { 190 stq_be_p(&rep->magic, NBD_REP_MAGIC); 191 stl_be_p(&rep->option, option); 192 stl_be_p(&rep->type, type); 193 stl_be_p(&rep->length, length); 194 } 195 196 /* Send a reply header, including length, but no payload. 197 * Return -errno on error, 0 on success. */ 198 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 199 uint32_t len, Error **errp) 200 { 201 NBDOptionReply rep; 202 203 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 204 type, nbd_rep_lookup(type), len); 205 206 assert(len < NBD_MAX_BUFFER_SIZE); 207 208 set_be_option_rep(&rep, client->opt, type, len); 209 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 210 } 211 212 /* Send a reply header with default 0 length. 213 * Return -errno on error, 0 on success. */ 214 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 215 Error **errp) 216 { 217 return nbd_negotiate_send_rep_len(client, type, 0, errp); 218 } 219 220 /* Send an error reply. 221 * Return -errno on error, 0 on success. */ 222 static int G_GNUC_PRINTF(4, 0) 223 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 224 Error **errp, const char *fmt, va_list va) 225 { 226 ERRP_GUARD(); 227 g_autofree char *msg = NULL; 228 int ret; 229 size_t len; 230 231 msg = g_strdup_vprintf(fmt, va); 232 len = strlen(msg); 233 assert(len < NBD_MAX_STRING_SIZE); 234 trace_nbd_negotiate_send_rep_err(msg); 235 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 236 if (ret < 0) { 237 return ret; 238 } 239 if (nbd_write(client->ioc, msg, len, errp) < 0) { 240 error_prepend(errp, "write failed (error message): "); 241 return -EIO; 242 } 243 244 return 0; 245 } 246 247 /* 248 * Return a malloc'd copy of @name suitable for use in an error reply. 249 */ 250 static char * 251 nbd_sanitize_name(const char *name) 252 { 253 if (strnlen(name, 80) < 80) { 254 return g_strdup(name); 255 } 256 /* XXX Should we also try to sanitize any control characters? */ 257 return g_strdup_printf("%.80s...", name); 258 } 259 260 /* Send an error reply. 261 * Return -errno on error, 0 on success. */ 262 static int G_GNUC_PRINTF(4, 5) 263 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 264 Error **errp, const char *fmt, ...) 265 { 266 va_list va; 267 int ret; 268 269 va_start(va, fmt); 270 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 271 va_end(va); 272 return ret; 273 } 274 275 /* Drop remainder of the current option, and send a reply with the 276 * given error type and message. Return -errno on read or write 277 * failure; or 0 if connection is still live. */ 278 static int G_GNUC_PRINTF(4, 0) 279 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 280 const char *fmt, va_list va) 281 { 282 int ret = nbd_drop(client->ioc, client->optlen, errp); 283 284 client->optlen = 0; 285 if (!ret) { 286 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 287 } 288 return ret; 289 } 290 291 static int G_GNUC_PRINTF(4, 5) 292 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 293 const char *fmt, ...) 294 { 295 int ret; 296 va_list va; 297 298 va_start(va, fmt); 299 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 300 va_end(va); 301 302 return ret; 303 } 304 305 static int G_GNUC_PRINTF(3, 4) 306 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 307 { 308 int ret; 309 va_list va; 310 311 va_start(va, fmt); 312 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 313 va_end(va); 314 315 return ret; 316 } 317 318 /* Read size bytes from the unparsed payload of the current option. 319 * If @check_nul, require that no NUL bytes appear in buffer. 320 * Return -errno on I/O error, 0 if option was completely handled by 321 * sending a reply about inconsistent lengths, or 1 on success. */ 322 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 323 bool check_nul, Error **errp) 324 { 325 if (size > client->optlen) { 326 return nbd_opt_invalid(client, errp, 327 "Inconsistent lengths in option %s", 328 nbd_opt_lookup(client->opt)); 329 } 330 client->optlen -= size; 331 if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) { 332 return -EIO; 333 } 334 335 if (check_nul && strnlen(buffer, size) != size) { 336 return nbd_opt_invalid(client, errp, 337 "Unexpected embedded NUL in option %s", 338 nbd_opt_lookup(client->opt)); 339 } 340 return 1; 341 } 342 343 /* Drop size bytes from the unparsed payload of the current option. 344 * Return -errno on I/O error, 0 if option was completely handled by 345 * sending a reply about inconsistent lengths, or 1 on success. */ 346 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 347 { 348 if (size > client->optlen) { 349 return nbd_opt_invalid(client, errp, 350 "Inconsistent lengths in option %s", 351 nbd_opt_lookup(client->opt)); 352 } 353 client->optlen -= size; 354 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 355 } 356 357 /* nbd_opt_read_name 358 * 359 * Read a string with the format: 360 * uint32_t len (<= NBD_MAX_STRING_SIZE) 361 * len bytes string (not 0-terminated) 362 * 363 * On success, @name will be allocated. 364 * If @length is non-null, it will be set to the actual string length. 365 * 366 * Return -errno on I/O error, 0 if option was completely handled by 367 * sending a reply about inconsistent lengths, or 1 on success. 368 */ 369 static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length, 370 Error **errp) 371 { 372 int ret; 373 uint32_t len; 374 g_autofree char *local_name = NULL; 375 376 *name = NULL; 377 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 378 if (ret <= 0) { 379 return ret; 380 } 381 len = cpu_to_be32(len); 382 383 if (len > NBD_MAX_STRING_SIZE) { 384 return nbd_opt_invalid(client, errp, 385 "Invalid name length: %" PRIu32, len); 386 } 387 388 local_name = g_malloc(len + 1); 389 ret = nbd_opt_read(client, local_name, len, true, errp); 390 if (ret <= 0) { 391 return ret; 392 } 393 local_name[len] = '\0'; 394 395 if (length) { 396 *length = len; 397 } 398 *name = g_steal_pointer(&local_name); 399 400 return 1; 401 } 402 403 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 404 * Return -errno on error, 0 on success. */ 405 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 406 Error **errp) 407 { 408 ERRP_GUARD(); 409 size_t name_len, desc_len; 410 uint32_t len; 411 const char *name = exp->name ? exp->name : ""; 412 const char *desc = exp->description ? exp->description : ""; 413 QIOChannel *ioc = client->ioc; 414 int ret; 415 416 trace_nbd_negotiate_send_rep_list(name, desc); 417 name_len = strlen(name); 418 desc_len = strlen(desc); 419 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE); 420 len = name_len + desc_len + sizeof(len); 421 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 422 if (ret < 0) { 423 return ret; 424 } 425 426 len = cpu_to_be32(name_len); 427 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 428 error_prepend(errp, "write failed (name length): "); 429 return -EINVAL; 430 } 431 432 if (nbd_write(ioc, name, name_len, errp) < 0) { 433 error_prepend(errp, "write failed (name buffer): "); 434 return -EINVAL; 435 } 436 437 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 438 error_prepend(errp, "write failed (description buffer): "); 439 return -EINVAL; 440 } 441 442 return 0; 443 } 444 445 /* Process the NBD_OPT_LIST command, with a potential series of replies. 446 * Return -errno on error, 0 on success. */ 447 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 448 { 449 NBDExport *exp; 450 assert(client->opt == NBD_OPT_LIST); 451 452 /* For each export, send a NBD_REP_SERVER reply. */ 453 QTAILQ_FOREACH(exp, &exports, next) { 454 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 455 return -EINVAL; 456 } 457 } 458 /* Finish with a NBD_REP_ACK. */ 459 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 460 } 461 462 static void nbd_check_meta_export(NBDClient *client, NBDExport *exp) 463 { 464 if (exp != client->contexts.exp) { 465 client->contexts.count = 0; 466 } 467 } 468 469 /* Send a reply to NBD_OPT_EXPORT_NAME. 470 * Return -errno on error, 0 on success. */ 471 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, 472 Error **errp) 473 { 474 ERRP_GUARD(); 475 g_autofree char *name = NULL; 476 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 477 size_t len; 478 int ret; 479 uint16_t myflags; 480 481 /* Client sends: 482 [20 .. xx] export name (length bytes) 483 Server replies: 484 [ 0 .. 7] size 485 [ 8 .. 9] export flags 486 [10 .. 133] reserved (0) [unless no_zeroes] 487 */ 488 trace_nbd_negotiate_handle_export_name(); 489 if (client->mode >= NBD_MODE_EXTENDED) { 490 error_setg(errp, "Extended headers already negotiated"); 491 return -EINVAL; 492 } 493 if (client->optlen > NBD_MAX_STRING_SIZE) { 494 error_setg(errp, "Bad length received"); 495 return -EINVAL; 496 } 497 name = g_malloc(client->optlen + 1); 498 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 499 return -EIO; 500 } 501 name[client->optlen] = '\0'; 502 client->optlen = 0; 503 504 trace_nbd_negotiate_handle_export_name_request(name); 505 506 client->exp = nbd_export_find(name); 507 if (!client->exp) { 508 error_setg(errp, "export not found"); 509 return -EINVAL; 510 } 511 nbd_check_meta_export(client, client->exp); 512 513 myflags = client->exp->nbdflags; 514 if (client->mode >= NBD_MODE_STRUCTURED) { 515 myflags |= NBD_FLAG_SEND_DF; 516 } 517 if (client->mode >= NBD_MODE_EXTENDED && client->contexts.count) { 518 myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD; 519 } 520 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags); 521 stq_be_p(buf, client->exp->size); 522 stw_be_p(buf + 8, myflags); 523 len = no_zeroes ? 10 : sizeof(buf); 524 ret = nbd_write(client->ioc, buf, len, errp); 525 if (ret < 0) { 526 error_prepend(errp, "write failed: "); 527 return ret; 528 } 529 530 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 531 blk_exp_ref(&client->exp->common); 532 533 return 0; 534 } 535 536 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 537 * The buffer does NOT include the info type prefix. 538 * Return -errno on error, 0 if ready to send more. */ 539 static int nbd_negotiate_send_info(NBDClient *client, 540 uint16_t info, uint32_t length, void *buf, 541 Error **errp) 542 { 543 int rc; 544 545 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 546 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 547 sizeof(info) + length, errp); 548 if (rc < 0) { 549 return rc; 550 } 551 info = cpu_to_be16(info); 552 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 553 return -EIO; 554 } 555 if (nbd_write(client->ioc, buf, length, errp) < 0) { 556 return -EIO; 557 } 558 return 0; 559 } 560 561 /* nbd_reject_length: Handle any unexpected payload. 562 * @fatal requests that we quit talking to the client, even if we are able 563 * to successfully send an error reply. 564 * Return: 565 * -errno transmission error occurred or @fatal was requested, errp is set 566 * 0 error message successfully sent to client, errp is not set 567 */ 568 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 569 { 570 int ret; 571 572 assert(client->optlen); 573 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 574 nbd_opt_lookup(client->opt)); 575 if (fatal && !ret) { 576 error_setg(errp, "option '%s' has unexpected length", 577 nbd_opt_lookup(client->opt)); 578 return -EINVAL; 579 } 580 return ret; 581 } 582 583 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 584 * Return -errno on error, 0 if ready for next option, and 1 to move 585 * into transmission phase. */ 586 static int nbd_negotiate_handle_info(NBDClient *client, Error **errp) 587 { 588 int rc; 589 g_autofree char *name = NULL; 590 NBDExport *exp; 591 uint16_t requests; 592 uint16_t request; 593 uint32_t namelen = 0; 594 bool sendname = false; 595 bool blocksize = false; 596 uint32_t sizes[3]; 597 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 598 uint32_t check_align = 0; 599 uint16_t myflags; 600 601 /* Client sends: 602 4 bytes: L, name length (can be 0) 603 L bytes: export name 604 2 bytes: N, number of requests (can be 0) 605 N * 2 bytes: N requests 606 */ 607 rc = nbd_opt_read_name(client, &name, &namelen, errp); 608 if (rc <= 0) { 609 return rc; 610 } 611 trace_nbd_negotiate_handle_export_name_request(name); 612 613 rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp); 614 if (rc <= 0) { 615 return rc; 616 } 617 requests = be16_to_cpu(requests); 618 trace_nbd_negotiate_handle_info_requests(requests); 619 while (requests--) { 620 rc = nbd_opt_read(client, &request, sizeof(request), false, errp); 621 if (rc <= 0) { 622 return rc; 623 } 624 request = be16_to_cpu(request); 625 trace_nbd_negotiate_handle_info_request(request, 626 nbd_info_lookup(request)); 627 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 628 * everything else is either a request we don't know or 629 * something we send regardless of request */ 630 switch (request) { 631 case NBD_INFO_NAME: 632 sendname = true; 633 break; 634 case NBD_INFO_BLOCK_SIZE: 635 blocksize = true; 636 break; 637 } 638 } 639 if (client->optlen) { 640 return nbd_reject_length(client, false, errp); 641 } 642 643 exp = nbd_export_find(name); 644 if (!exp) { 645 g_autofree char *sane_name = nbd_sanitize_name(name); 646 647 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 648 errp, "export '%s' not present", 649 sane_name); 650 } 651 if (client->opt == NBD_OPT_GO) { 652 nbd_check_meta_export(client, exp); 653 } 654 655 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 656 if (sendname) { 657 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 658 errp); 659 if (rc < 0) { 660 return rc; 661 } 662 } 663 664 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 665 * client request */ 666 if (exp->description) { 667 size_t len = strlen(exp->description); 668 669 assert(len <= NBD_MAX_STRING_SIZE); 670 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 671 len, exp->description, errp); 672 if (rc < 0) { 673 return rc; 674 } 675 } 676 677 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 678 * according to whether the client requested it, and according to 679 * whether this is OPT_INFO or OPT_GO. */ 680 /* minimum - 1 for back-compat, or actual if client will obey it. */ 681 if (client->opt == NBD_OPT_INFO || blocksize) { 682 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk); 683 } else { 684 sizes[0] = 1; 685 } 686 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 687 /* preferred - Hard-code to 4096 for now. 688 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 689 sizes[1] = MAX(4096, sizes[0]); 690 /* maximum - At most 32M, but smaller as appropriate. */ 691 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE); 692 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 693 sizes[0] = cpu_to_be32(sizes[0]); 694 sizes[1] = cpu_to_be32(sizes[1]); 695 sizes[2] = cpu_to_be32(sizes[2]); 696 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 697 sizeof(sizes), sizes, errp); 698 if (rc < 0) { 699 return rc; 700 } 701 702 /* Send NBD_INFO_EXPORT always */ 703 myflags = exp->nbdflags; 704 if (client->mode >= NBD_MODE_STRUCTURED) { 705 myflags |= NBD_FLAG_SEND_DF; 706 } 707 if (client->mode >= NBD_MODE_EXTENDED && 708 (client->contexts.count || client->opt == NBD_OPT_INFO)) { 709 myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD; 710 } 711 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags); 712 stq_be_p(buf, exp->size); 713 stw_be_p(buf + 8, myflags); 714 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 715 sizeof(buf), buf, errp); 716 if (rc < 0) { 717 return rc; 718 } 719 720 /* 721 * If the client is just asking for NBD_OPT_INFO, but forgot to 722 * request block sizes in a situation that would impact 723 * performance, then return an error. But for NBD_OPT_GO, we 724 * tolerate all clients, regardless of alignments. 725 */ 726 if (client->opt == NBD_OPT_INFO && !blocksize && 727 blk_get_request_alignment(exp->common.blk) > 1) { 728 return nbd_negotiate_send_rep_err(client, 729 NBD_REP_ERR_BLOCK_SIZE_REQD, 730 errp, 731 "request NBD_INFO_BLOCK_SIZE to " 732 "use this export"); 733 } 734 735 /* Final reply */ 736 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 737 if (rc < 0) { 738 return rc; 739 } 740 741 if (client->opt == NBD_OPT_GO) { 742 client->exp = exp; 743 client->check_align = check_align; 744 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 745 blk_exp_ref(&client->exp->common); 746 rc = 1; 747 } 748 return rc; 749 } 750 751 752 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 753 * new channel for all further (now-encrypted) communication. */ 754 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 755 Error **errp) 756 { 757 QIOChannel *ioc; 758 QIOChannelTLS *tioc; 759 struct NBDTLSHandshakeData data = { 0 }; 760 761 assert(client->opt == NBD_OPT_STARTTLS); 762 763 trace_nbd_negotiate_handle_starttls(); 764 ioc = client->ioc; 765 766 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 767 return NULL; 768 } 769 770 tioc = qio_channel_tls_new_server(ioc, 771 client->tlscreds, 772 client->tlsauthz, 773 errp); 774 if (!tioc) { 775 return NULL; 776 } 777 778 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 779 trace_nbd_negotiate_handle_starttls_handshake(); 780 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 781 qio_channel_tls_handshake(tioc, 782 nbd_tls_handshake, 783 &data, 784 NULL, 785 NULL); 786 787 if (!data.complete) { 788 g_main_loop_run(data.loop); 789 } 790 g_main_loop_unref(data.loop); 791 if (data.error) { 792 object_unref(OBJECT(tioc)); 793 error_propagate(errp, data.error); 794 return NULL; 795 } 796 797 return QIO_CHANNEL(tioc); 798 } 799 800 /* nbd_negotiate_send_meta_context 801 * 802 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 803 * 804 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 805 */ 806 static int nbd_negotiate_send_meta_context(NBDClient *client, 807 const char *context, 808 uint32_t context_id, 809 Error **errp) 810 { 811 NBDOptionReplyMetaContext opt; 812 struct iovec iov[] = { 813 {.iov_base = &opt, .iov_len = sizeof(opt)}, 814 {.iov_base = (void *)context, .iov_len = strlen(context)} 815 }; 816 817 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE); 818 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 819 context_id = 0; 820 } 821 822 trace_nbd_negotiate_meta_query_reply(context, context_id); 823 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 824 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 825 stl_be_p(&opt.context_id, context_id); 826 827 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 828 } 829 830 /* 831 * Return true if @query matches @pattern, or if @query is empty when 832 * the @client is performing _LIST_. 833 */ 834 static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 835 const char *query) 836 { 837 if (!*query) { 838 trace_nbd_negotiate_meta_query_parse("empty"); 839 return client->opt == NBD_OPT_LIST_META_CONTEXT; 840 } 841 if (strcmp(query, pattern) == 0) { 842 trace_nbd_negotiate_meta_query_parse(pattern); 843 return true; 844 } 845 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 846 return false; 847 } 848 849 /* 850 * Return true and adjust @str in place if it begins with @prefix. 851 */ 852 static bool nbd_strshift(const char **str, const char *prefix) 853 { 854 size_t len = strlen(prefix); 855 856 if (strncmp(*str, prefix, len) == 0) { 857 *str += len; 858 return true; 859 } 860 return false; 861 } 862 863 /* nbd_meta_base_query 864 * 865 * Handle queries to 'base' namespace. For now, only the base:allocation 866 * context is available. Return true if @query has been handled. 867 */ 868 static bool nbd_meta_base_query(NBDClient *client, NBDMetaContexts *meta, 869 const char *query) 870 { 871 if (!nbd_strshift(&query, "base:")) { 872 return false; 873 } 874 trace_nbd_negotiate_meta_query_parse("base:"); 875 876 if (nbd_meta_empty_or_pattern(client, "allocation", query)) { 877 meta->base_allocation = true; 878 } 879 return true; 880 } 881 882 /* nbd_meta_qemu_query 883 * 884 * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap: 885 * and qemu:allocation-depth contexts are available. Return true if @query 886 * has been handled. 887 */ 888 static bool nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *meta, 889 const char *query) 890 { 891 size_t i; 892 893 if (!nbd_strshift(&query, "qemu:")) { 894 return false; 895 } 896 trace_nbd_negotiate_meta_query_parse("qemu:"); 897 898 if (!*query) { 899 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 900 meta->allocation_depth = meta->exp->allocation_depth; 901 if (meta->exp->nr_export_bitmaps) { 902 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 903 } 904 } 905 trace_nbd_negotiate_meta_query_parse("empty"); 906 return true; 907 } 908 909 if (strcmp(query, "allocation-depth") == 0) { 910 trace_nbd_negotiate_meta_query_parse("allocation-depth"); 911 meta->allocation_depth = meta->exp->allocation_depth; 912 return true; 913 } 914 915 if (nbd_strshift(&query, "dirty-bitmap:")) { 916 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 917 if (!*query) { 918 if (client->opt == NBD_OPT_LIST_META_CONTEXT && 919 meta->exp->nr_export_bitmaps) { 920 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 921 } 922 trace_nbd_negotiate_meta_query_parse("empty"); 923 return true; 924 } 925 926 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 927 const char *bm_name; 928 929 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 930 if (strcmp(bm_name, query) == 0) { 931 meta->bitmaps[i] = true; 932 trace_nbd_negotiate_meta_query_parse(query); 933 return true; 934 } 935 } 936 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap match"); 937 return true; 938 } 939 940 trace_nbd_negotiate_meta_query_skip("unknown qemu context"); 941 return true; 942 } 943 944 /* nbd_negotiate_meta_query 945 * 946 * Parse namespace name and call corresponding function to parse body of the 947 * query. 948 * 949 * The only supported namespaces are 'base' and 'qemu'. 950 * 951 * Return -errno on I/O error, 0 if option was completely handled by 952 * sending a reply about inconsistent lengths, or 1 on success. */ 953 static int nbd_negotiate_meta_query(NBDClient *client, 954 NBDMetaContexts *meta, Error **errp) 955 { 956 int ret; 957 g_autofree char *query = NULL; 958 uint32_t len; 959 960 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 961 if (ret <= 0) { 962 return ret; 963 } 964 len = cpu_to_be32(len); 965 966 if (len > NBD_MAX_STRING_SIZE) { 967 trace_nbd_negotiate_meta_query_skip("length too long"); 968 return nbd_opt_skip(client, len, errp); 969 } 970 971 query = g_malloc(len + 1); 972 ret = nbd_opt_read(client, query, len, true, errp); 973 if (ret <= 0) { 974 return ret; 975 } 976 query[len] = '\0'; 977 978 if (nbd_meta_base_query(client, meta, query)) { 979 return 1; 980 } 981 if (nbd_meta_qemu_query(client, meta, query)) { 982 return 1; 983 } 984 985 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 986 return 1; 987 } 988 989 /* nbd_negotiate_meta_queries 990 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 991 * 992 * Return -errno on I/O error, or 0 if option was completely handled. */ 993 static int nbd_negotiate_meta_queries(NBDClient *client, Error **errp) 994 { 995 int ret; 996 g_autofree char *export_name = NULL; 997 /* Mark unused to work around https://bugs.llvm.org/show_bug.cgi?id=3888 */ 998 g_autofree G_GNUC_UNUSED bool *bitmaps = NULL; 999 NBDMetaContexts local_meta = {0}; 1000 NBDMetaContexts *meta; 1001 uint32_t nb_queries; 1002 size_t i; 1003 size_t count = 0; 1004 1005 if (client->opt == NBD_OPT_SET_META_CONTEXT && 1006 client->mode < NBD_MODE_STRUCTURED) { 1007 return nbd_opt_invalid(client, errp, 1008 "request option '%s' when structured reply " 1009 "is not negotiated", 1010 nbd_opt_lookup(client->opt)); 1011 } 1012 1013 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1014 /* Only change the caller's meta on SET. */ 1015 meta = &local_meta; 1016 } else { 1017 meta = &client->contexts; 1018 } 1019 1020 g_free(meta->bitmaps); 1021 memset(meta, 0, sizeof(*meta)); 1022 1023 ret = nbd_opt_read_name(client, &export_name, NULL, errp); 1024 if (ret <= 0) { 1025 return ret; 1026 } 1027 1028 meta->exp = nbd_export_find(export_name); 1029 if (meta->exp == NULL) { 1030 g_autofree char *sane_name = nbd_sanitize_name(export_name); 1031 1032 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 1033 "export '%s' not present", sane_name); 1034 } 1035 meta->bitmaps = g_new0(bool, meta->exp->nr_export_bitmaps); 1036 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1037 bitmaps = meta->bitmaps; 1038 } 1039 1040 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp); 1041 if (ret <= 0) { 1042 return ret; 1043 } 1044 nb_queries = cpu_to_be32(nb_queries); 1045 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 1046 export_name, nb_queries); 1047 1048 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 1049 /* enable all known contexts */ 1050 meta->base_allocation = true; 1051 meta->allocation_depth = meta->exp->allocation_depth; 1052 if (meta->exp->nr_export_bitmaps) { 1053 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 1054 } 1055 } else { 1056 for (i = 0; i < nb_queries; ++i) { 1057 ret = nbd_negotiate_meta_query(client, meta, errp); 1058 if (ret <= 0) { 1059 return ret; 1060 } 1061 } 1062 } 1063 1064 if (meta->base_allocation) { 1065 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1066 NBD_META_ID_BASE_ALLOCATION, 1067 errp); 1068 if (ret < 0) { 1069 return ret; 1070 } 1071 count++; 1072 } 1073 1074 if (meta->allocation_depth) { 1075 ret = nbd_negotiate_send_meta_context(client, "qemu:allocation-depth", 1076 NBD_META_ID_ALLOCATION_DEPTH, 1077 errp); 1078 if (ret < 0) { 1079 return ret; 1080 } 1081 count++; 1082 } 1083 1084 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 1085 const char *bm_name; 1086 g_autofree char *context = NULL; 1087 1088 if (!meta->bitmaps[i]) { 1089 continue; 1090 } 1091 1092 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 1093 context = g_strdup_printf("qemu:dirty-bitmap:%s", bm_name); 1094 1095 ret = nbd_negotiate_send_meta_context(client, context, 1096 NBD_META_ID_DIRTY_BITMAP + i, 1097 errp); 1098 if (ret < 0) { 1099 return ret; 1100 } 1101 count++; 1102 } 1103 1104 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1105 if (ret == 0) { 1106 meta->count = count; 1107 } 1108 1109 return ret; 1110 } 1111 1112 /* nbd_negotiate_options 1113 * Process all NBD_OPT_* client option commands, during fixed newstyle 1114 * negotiation. 1115 * Return: 1116 * -errno on error, errp is set 1117 * 0 on successful negotiation, errp is not set 1118 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1119 * errp is not set 1120 */ 1121 static int nbd_negotiate_options(NBDClient *client, Error **errp) 1122 { 1123 uint32_t flags; 1124 bool fixedNewstyle = false; 1125 bool no_zeroes = false; 1126 1127 /* Client sends: 1128 [ 0 .. 3] client flags 1129 1130 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1131 [ 0 .. 7] NBD_OPTS_MAGIC 1132 [ 8 .. 11] NBD option 1133 [12 .. 15] Data length 1134 ... Rest of request 1135 1136 [ 0 .. 7] NBD_OPTS_MAGIC 1137 [ 8 .. 11] Second NBD option 1138 [12 .. 15] Data length 1139 ... Rest of request 1140 */ 1141 1142 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1143 return -EIO; 1144 } 1145 client->mode = NBD_MODE_EXPORT_NAME; 1146 trace_nbd_negotiate_options_flags(flags); 1147 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1148 fixedNewstyle = true; 1149 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1150 client->mode = NBD_MODE_SIMPLE; 1151 } 1152 if (flags & NBD_FLAG_C_NO_ZEROES) { 1153 no_zeroes = true; 1154 flags &= ~NBD_FLAG_C_NO_ZEROES; 1155 } 1156 if (flags != 0) { 1157 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1158 return -EINVAL; 1159 } 1160 1161 while (1) { 1162 int ret; 1163 uint32_t option, length; 1164 uint64_t magic; 1165 1166 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1167 return -EINVAL; 1168 } 1169 trace_nbd_negotiate_options_check_magic(magic); 1170 if (magic != NBD_OPTS_MAGIC) { 1171 error_setg(errp, "Bad magic received"); 1172 return -EINVAL; 1173 } 1174 1175 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1176 return -EINVAL; 1177 } 1178 client->opt = option; 1179 1180 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1181 return -EINVAL; 1182 } 1183 assert(!client->optlen); 1184 client->optlen = length; 1185 1186 if (length > NBD_MAX_BUFFER_SIZE) { 1187 error_setg(errp, "len (%" PRIu32 ") is larger than max len (%u)", 1188 length, NBD_MAX_BUFFER_SIZE); 1189 return -EINVAL; 1190 } 1191 1192 trace_nbd_negotiate_options_check_option(option, 1193 nbd_opt_lookup(option)); 1194 if (client->tlscreds && 1195 client->ioc == (QIOChannel *)client->sioc) { 1196 QIOChannel *tioc; 1197 if (!fixedNewstyle) { 1198 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1199 return -EINVAL; 1200 } 1201 switch (option) { 1202 case NBD_OPT_STARTTLS: 1203 if (length) { 1204 /* Unconditionally drop the connection if the client 1205 * can't start a TLS negotiation correctly */ 1206 return nbd_reject_length(client, true, errp); 1207 } 1208 tioc = nbd_negotiate_handle_starttls(client, errp); 1209 if (!tioc) { 1210 return -EIO; 1211 } 1212 ret = 0; 1213 object_unref(OBJECT(client->ioc)); 1214 client->ioc = tioc; 1215 break; 1216 1217 case NBD_OPT_EXPORT_NAME: 1218 /* No way to return an error to client, so drop connection */ 1219 error_setg(errp, "Option 0x%x not permitted before TLS", 1220 option); 1221 return -EINVAL; 1222 1223 default: 1224 /* Let the client keep trying, unless they asked to 1225 * quit. Always try to give an error back to the 1226 * client; but when replying to OPT_ABORT, be aware 1227 * that the client may hang up before receiving the 1228 * error, in which case we are fine ignoring the 1229 * resulting EPIPE. */ 1230 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1231 option == NBD_OPT_ABORT ? NULL : errp, 1232 "Option 0x%" PRIx32 1233 " not permitted before TLS", option); 1234 if (option == NBD_OPT_ABORT) { 1235 return 1; 1236 } 1237 break; 1238 } 1239 } else if (fixedNewstyle) { 1240 switch (option) { 1241 case NBD_OPT_LIST: 1242 if (length) { 1243 ret = nbd_reject_length(client, false, errp); 1244 } else { 1245 ret = nbd_negotiate_handle_list(client, errp); 1246 } 1247 break; 1248 1249 case NBD_OPT_ABORT: 1250 /* NBD spec says we must try to reply before 1251 * disconnecting, but that we must also tolerate 1252 * guests that don't wait for our reply. */ 1253 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1254 return 1; 1255 1256 case NBD_OPT_EXPORT_NAME: 1257 return nbd_negotiate_handle_export_name(client, no_zeroes, 1258 errp); 1259 1260 case NBD_OPT_INFO: 1261 case NBD_OPT_GO: 1262 ret = nbd_negotiate_handle_info(client, errp); 1263 if (ret == 1) { 1264 assert(option == NBD_OPT_GO); 1265 return 0; 1266 } 1267 break; 1268 1269 case NBD_OPT_STARTTLS: 1270 if (length) { 1271 ret = nbd_reject_length(client, false, errp); 1272 } else if (client->tlscreds) { 1273 ret = nbd_negotiate_send_rep_err(client, 1274 NBD_REP_ERR_INVALID, errp, 1275 "TLS already enabled"); 1276 } else { 1277 ret = nbd_negotiate_send_rep_err(client, 1278 NBD_REP_ERR_POLICY, errp, 1279 "TLS not configured"); 1280 } 1281 break; 1282 1283 case NBD_OPT_STRUCTURED_REPLY: 1284 if (length) { 1285 ret = nbd_reject_length(client, false, errp); 1286 } else if (client->mode >= NBD_MODE_EXTENDED) { 1287 ret = nbd_negotiate_send_rep_err( 1288 client, NBD_REP_ERR_EXT_HEADER_REQD, errp, 1289 "extended headers already negotiated"); 1290 } else if (client->mode >= NBD_MODE_STRUCTURED) { 1291 ret = nbd_negotiate_send_rep_err( 1292 client, NBD_REP_ERR_INVALID, errp, 1293 "structured reply already negotiated"); 1294 } else { 1295 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1296 client->mode = NBD_MODE_STRUCTURED; 1297 } 1298 break; 1299 1300 case NBD_OPT_LIST_META_CONTEXT: 1301 case NBD_OPT_SET_META_CONTEXT: 1302 ret = nbd_negotiate_meta_queries(client, errp); 1303 break; 1304 1305 case NBD_OPT_EXTENDED_HEADERS: 1306 if (length) { 1307 ret = nbd_reject_length(client, false, errp); 1308 } else if (client->mode >= NBD_MODE_EXTENDED) { 1309 ret = nbd_negotiate_send_rep_err( 1310 client, NBD_REP_ERR_INVALID, errp, 1311 "extended headers already negotiated"); 1312 } else { 1313 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1314 client->mode = NBD_MODE_EXTENDED; 1315 } 1316 break; 1317 1318 default: 1319 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1320 "Unsupported option %" PRIu32 " (%s)", 1321 option, nbd_opt_lookup(option)); 1322 break; 1323 } 1324 } else { 1325 /* 1326 * If broken new-style we should drop the connection 1327 * for anything except NBD_OPT_EXPORT_NAME 1328 */ 1329 switch (option) { 1330 case NBD_OPT_EXPORT_NAME: 1331 return nbd_negotiate_handle_export_name(client, no_zeroes, 1332 errp); 1333 1334 default: 1335 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1336 option, nbd_opt_lookup(option)); 1337 return -EINVAL; 1338 } 1339 } 1340 if (ret < 0) { 1341 return ret; 1342 } 1343 } 1344 } 1345 1346 /* nbd_negotiate 1347 * Return: 1348 * -errno on error, errp is set 1349 * 0 on successful negotiation, errp is not set 1350 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1351 * errp is not set 1352 */ 1353 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1354 { 1355 ERRP_GUARD(); 1356 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1357 int ret; 1358 1359 /* Old style negotiation header, no room for options 1360 [ 0 .. 7] passwd ("NBDMAGIC") 1361 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1362 [16 .. 23] size 1363 [24 .. 27] export flags (zero-extended) 1364 [28 .. 151] reserved (0) 1365 1366 New style negotiation header, client can send options 1367 [ 0 .. 7] passwd ("NBDMAGIC") 1368 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1369 [16 .. 17] server flags (0) 1370 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1371 */ 1372 1373 qio_channel_set_blocking(client->ioc, false, NULL); 1374 qio_channel_set_follow_coroutine_ctx(client->ioc, true); 1375 1376 trace_nbd_negotiate_begin(); 1377 memcpy(buf, "NBDMAGIC", 8); 1378 1379 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1380 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1381 1382 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1383 error_prepend(errp, "write failed: "); 1384 return -EINVAL; 1385 } 1386 ret = nbd_negotiate_options(client, errp); 1387 if (ret != 0) { 1388 if (ret < 0) { 1389 error_prepend(errp, "option negotiation failed: "); 1390 } 1391 return ret; 1392 } 1393 1394 assert(!client->optlen); 1395 trace_nbd_negotiate_success(); 1396 1397 return 0; 1398 } 1399 1400 /* nbd_read_eof 1401 * Tries to read @size bytes from @ioc. This is a local implementation of 1402 * qio_channel_readv_all_eof. We have it here because we need it to be 1403 * interruptible and to know when the coroutine is yielding. 1404 * Returns 1 on success 1405 * 0 on eof, when no data was read (errp is not set) 1406 * negative errno on failure (errp is set) 1407 */ 1408 static inline int coroutine_fn 1409 nbd_read_eof(NBDClient *client, void *buffer, size_t size, Error **errp) 1410 { 1411 bool partial = false; 1412 1413 assert(size); 1414 while (size > 0) { 1415 struct iovec iov = { .iov_base = buffer, .iov_len = size }; 1416 ssize_t len; 1417 1418 len = qio_channel_readv(client->ioc, &iov, 1, errp); 1419 if (len == QIO_CHANNEL_ERR_BLOCK) { 1420 WITH_QEMU_LOCK_GUARD(&client->lock) { 1421 client->read_yielding = true; 1422 1423 /* Prompt main loop thread to re-run nbd_drained_poll() */ 1424 aio_wait_kick(); 1425 } 1426 qio_channel_yield(client->ioc, G_IO_IN); 1427 WITH_QEMU_LOCK_GUARD(&client->lock) { 1428 client->read_yielding = false; 1429 if (client->quiescing) { 1430 return -EAGAIN; 1431 } 1432 } 1433 continue; 1434 } else if (len < 0) { 1435 return -EIO; 1436 } else if (len == 0) { 1437 if (partial) { 1438 error_setg(errp, 1439 "Unexpected end-of-file before all bytes were read"); 1440 return -EIO; 1441 } else { 1442 return 0; 1443 } 1444 } 1445 1446 partial = true; 1447 size -= len; 1448 buffer = (uint8_t *) buffer + len; 1449 } 1450 return 1; 1451 } 1452 1453 static int coroutine_fn nbd_receive_request(NBDClient *client, NBDRequest *request, 1454 Error **errp) 1455 { 1456 uint8_t buf[NBD_EXTENDED_REQUEST_SIZE]; 1457 uint32_t magic, expect; 1458 int ret; 1459 size_t size = client->mode >= NBD_MODE_EXTENDED ? 1460 NBD_EXTENDED_REQUEST_SIZE : NBD_REQUEST_SIZE; 1461 1462 ret = nbd_read_eof(client, buf, size, errp); 1463 if (ret < 0) { 1464 return ret; 1465 } 1466 if (ret == 0) { 1467 return -EIO; 1468 } 1469 1470 /* 1471 * Compact request 1472 * [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1473 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1474 * [ 6 .. 7] type (NBD_CMD_READ, ...) 1475 * [ 8 .. 15] cookie 1476 * [16 .. 23] from 1477 * [24 .. 27] len 1478 * Extended request 1479 * [ 0 .. 3] magic (NBD_EXTENDED_REQUEST_MAGIC) 1480 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, NBD_CMD_FLAG_PAYLOAD_LEN, ...) 1481 * [ 6 .. 7] type (NBD_CMD_READ, ...) 1482 * [ 8 .. 15] cookie 1483 * [16 .. 23] from 1484 * [24 .. 31] len 1485 */ 1486 1487 magic = ldl_be_p(buf); 1488 request->flags = lduw_be_p(buf + 4); 1489 request->type = lduw_be_p(buf + 6); 1490 request->cookie = ldq_be_p(buf + 8); 1491 request->from = ldq_be_p(buf + 16); 1492 if (client->mode >= NBD_MODE_EXTENDED) { 1493 request->len = ldq_be_p(buf + 24); 1494 expect = NBD_EXTENDED_REQUEST_MAGIC; 1495 } else { 1496 request->len = (uint32_t)ldl_be_p(buf + 24); /* widen 32 to 64 bits */ 1497 expect = NBD_REQUEST_MAGIC; 1498 } 1499 1500 trace_nbd_receive_request(magic, request->flags, request->type, 1501 request->from, request->len); 1502 1503 if (magic != expect) { 1504 error_setg(errp, "invalid magic (got 0x%" PRIx32 ", expected 0x%" 1505 PRIx32 ")", magic, expect); 1506 return -EINVAL; 1507 } 1508 return 0; 1509 } 1510 1511 #define MAX_NBD_REQUESTS 16 1512 1513 /* Runs in export AioContext and main loop thread */ 1514 void nbd_client_get(NBDClient *client) 1515 { 1516 qatomic_inc(&client->refcount); 1517 } 1518 1519 void nbd_client_put(NBDClient *client) 1520 { 1521 assert(qemu_in_main_thread()); 1522 1523 if (qatomic_fetch_dec(&client->refcount) == 1) { 1524 /* The last reference should be dropped by client->close, 1525 * which is called by client_close. 1526 */ 1527 assert(client->closing); 1528 1529 object_unref(OBJECT(client->sioc)); 1530 object_unref(OBJECT(client->ioc)); 1531 if (client->tlscreds) { 1532 object_unref(OBJECT(client->tlscreds)); 1533 } 1534 g_free(client->tlsauthz); 1535 if (client->exp) { 1536 QTAILQ_REMOVE(&client->exp->clients, client, next); 1537 blk_exp_unref(&client->exp->common); 1538 } 1539 g_free(client->contexts.bitmaps); 1540 qemu_mutex_destroy(&client->lock); 1541 g_free(client); 1542 } 1543 } 1544 1545 /* 1546 * Tries to release the reference to @client, but only if other references 1547 * remain. This is an optimization for the common case where we want to avoid 1548 * the expense of scheduling nbd_client_put() in the main loop thread. 1549 * 1550 * Returns true upon success or false if the reference was not released because 1551 * it is the last reference. 1552 */ 1553 static bool nbd_client_put_nonzero(NBDClient *client) 1554 { 1555 int old = qatomic_read(&client->refcount); 1556 int expected; 1557 1558 do { 1559 if (old == 1) { 1560 return false; 1561 } 1562 1563 expected = old; 1564 old = qatomic_cmpxchg(&client->refcount, expected, expected - 1); 1565 } while (old != expected); 1566 1567 return true; 1568 } 1569 1570 static void client_close(NBDClient *client, bool negotiated) 1571 { 1572 assert(qemu_in_main_thread()); 1573 1574 WITH_QEMU_LOCK_GUARD(&client->lock) { 1575 if (client->closing) { 1576 return; 1577 } 1578 1579 client->closing = true; 1580 } 1581 1582 /* Force requests to finish. They will drop their own references, 1583 * then we'll close the socket and free the NBDClient. 1584 */ 1585 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1586 NULL); 1587 1588 /* Also tell the client, so that they release their reference. */ 1589 if (client->close_fn) { 1590 client->close_fn(client, negotiated); 1591 } 1592 } 1593 1594 /* Runs in export AioContext with client->lock held */ 1595 static NBDRequestData *nbd_request_get(NBDClient *client) 1596 { 1597 NBDRequestData *req; 1598 1599 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1600 client->nb_requests++; 1601 1602 req = g_new0(NBDRequestData, 1); 1603 req->client = client; 1604 return req; 1605 } 1606 1607 /* Runs in export AioContext with client->lock held */ 1608 static void nbd_request_put(NBDRequestData *req) 1609 { 1610 NBDClient *client = req->client; 1611 1612 if (req->data) { 1613 qemu_vfree(req->data); 1614 } 1615 g_free(req); 1616 1617 client->nb_requests--; 1618 1619 if (client->quiescing && client->nb_requests == 0) { 1620 aio_wait_kick(); 1621 } 1622 1623 nbd_client_receive_next_request(client); 1624 } 1625 1626 static void blk_aio_attached(AioContext *ctx, void *opaque) 1627 { 1628 NBDExport *exp = opaque; 1629 NBDClient *client; 1630 1631 assert(qemu_in_main_thread()); 1632 1633 trace_nbd_blk_aio_attached(exp->name, ctx); 1634 1635 exp->common.ctx = ctx; 1636 1637 QTAILQ_FOREACH(client, &exp->clients, next) { 1638 WITH_QEMU_LOCK_GUARD(&client->lock) { 1639 assert(client->nb_requests == 0); 1640 assert(client->recv_coroutine == NULL); 1641 assert(client->send_coroutine == NULL); 1642 } 1643 } 1644 } 1645 1646 static void blk_aio_detach(void *opaque) 1647 { 1648 NBDExport *exp = opaque; 1649 1650 assert(qemu_in_main_thread()); 1651 1652 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx); 1653 1654 exp->common.ctx = NULL; 1655 } 1656 1657 static void nbd_drained_begin(void *opaque) 1658 { 1659 NBDExport *exp = opaque; 1660 NBDClient *client; 1661 1662 assert(qemu_in_main_thread()); 1663 1664 QTAILQ_FOREACH(client, &exp->clients, next) { 1665 WITH_QEMU_LOCK_GUARD(&client->lock) { 1666 client->quiescing = true; 1667 } 1668 } 1669 } 1670 1671 static void nbd_drained_end(void *opaque) 1672 { 1673 NBDExport *exp = opaque; 1674 NBDClient *client; 1675 1676 assert(qemu_in_main_thread()); 1677 1678 QTAILQ_FOREACH(client, &exp->clients, next) { 1679 WITH_QEMU_LOCK_GUARD(&client->lock) { 1680 client->quiescing = false; 1681 nbd_client_receive_next_request(client); 1682 } 1683 } 1684 } 1685 1686 /* Runs in export AioContext */ 1687 static void nbd_wake_read_bh(void *opaque) 1688 { 1689 NBDClient *client = opaque; 1690 qio_channel_wake_read(client->ioc); 1691 } 1692 1693 static bool nbd_drained_poll(void *opaque) 1694 { 1695 NBDExport *exp = opaque; 1696 NBDClient *client; 1697 1698 assert(qemu_in_main_thread()); 1699 1700 QTAILQ_FOREACH(client, &exp->clients, next) { 1701 WITH_QEMU_LOCK_GUARD(&client->lock) { 1702 if (client->nb_requests != 0) { 1703 /* 1704 * If there's a coroutine waiting for a request on nbd_read_eof() 1705 * enter it here so we don't depend on the client to wake it up. 1706 * 1707 * Schedule a BH in the export AioContext to avoid missing the 1708 * wake up due to the race between qio_channel_wake_read() and 1709 * qio_channel_yield(). 1710 */ 1711 if (client->recv_coroutine != NULL && client->read_yielding) { 1712 aio_bh_schedule_oneshot(nbd_export_aio_context(client->exp), 1713 nbd_wake_read_bh, client); 1714 } 1715 1716 return true; 1717 } 1718 } 1719 } 1720 1721 return false; 1722 } 1723 1724 static void nbd_eject_notifier(Notifier *n, void *data) 1725 { 1726 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1727 1728 assert(qemu_in_main_thread()); 1729 1730 blk_exp_request_shutdown(&exp->common); 1731 } 1732 1733 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) 1734 { 1735 NBDExport *nbd_exp = container_of(exp, NBDExport, common); 1736 assert(exp->drv == &blk_exp_nbd); 1737 assert(nbd_exp->eject_notifier_blk == NULL); 1738 1739 blk_ref(blk); 1740 nbd_exp->eject_notifier_blk = blk; 1741 nbd_exp->eject_notifier.notify = nbd_eject_notifier; 1742 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier); 1743 } 1744 1745 static const BlockDevOps nbd_block_ops = { 1746 .drained_begin = nbd_drained_begin, 1747 .drained_end = nbd_drained_end, 1748 .drained_poll = nbd_drained_poll, 1749 }; 1750 1751 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, 1752 Error **errp) 1753 { 1754 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1755 BlockExportOptionsNbd *arg = &exp_args->u.nbd; 1756 const char *name = arg->name ?: exp_args->node_name; 1757 BlockBackend *blk = blk_exp->blk; 1758 int64_t size; 1759 uint64_t perm, shared_perm; 1760 bool readonly = !exp_args->writable; 1761 BlockDirtyBitmapOrStrList *bitmaps; 1762 size_t i; 1763 int ret; 1764 1765 GLOBAL_STATE_CODE(); 1766 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); 1767 1768 if (!nbd_server_is_running()) { 1769 error_setg(errp, "NBD server not running"); 1770 return -EINVAL; 1771 } 1772 1773 if (strlen(name) > NBD_MAX_STRING_SIZE) { 1774 error_setg(errp, "export name '%s' too long", name); 1775 return -EINVAL; 1776 } 1777 1778 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) { 1779 error_setg(errp, "description '%s' too long", arg->description); 1780 return -EINVAL; 1781 } 1782 1783 if (nbd_export_find(name)) { 1784 error_setg(errp, "NBD server already has export named '%s'", name); 1785 return -EEXIST; 1786 } 1787 1788 size = blk_getlength(blk); 1789 if (size < 0) { 1790 error_setg_errno(errp, -size, 1791 "Failed to determine the NBD export's length"); 1792 return size; 1793 } 1794 1795 /* Don't allow resize while the NBD server is running, otherwise we don't 1796 * care what happens with the node. */ 1797 blk_get_perm(blk, &perm, &shared_perm); 1798 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); 1799 if (ret < 0) { 1800 return ret; 1801 } 1802 1803 QTAILQ_INIT(&exp->clients); 1804 exp->name = g_strdup(name); 1805 exp->description = g_strdup(arg->description); 1806 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1807 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1808 1809 if (nbd_server_max_connections() != 1) { 1810 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1811 } 1812 if (readonly) { 1813 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1814 } else { 1815 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1816 NBD_FLAG_SEND_FAST_ZERO); 1817 } 1818 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1819 1820 bdrv_graph_rdlock_main_loop(); 1821 1822 for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) { 1823 exp->nr_export_bitmaps++; 1824 } 1825 exp->export_bitmaps = g_new0(BdrvDirtyBitmap *, exp->nr_export_bitmaps); 1826 for (i = 0, bitmaps = arg->bitmaps; bitmaps; 1827 i++, bitmaps = bitmaps->next) 1828 { 1829 const char *bitmap; 1830 BlockDriverState *bs = blk_bs(blk); 1831 BdrvDirtyBitmap *bm = NULL; 1832 1833 switch (bitmaps->value->type) { 1834 case QTYPE_QSTRING: 1835 bitmap = bitmaps->value->u.local; 1836 while (bs) { 1837 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1838 if (bm != NULL) { 1839 break; 1840 } 1841 1842 bs = bdrv_filter_or_cow_bs(bs); 1843 } 1844 1845 if (bm == NULL) { 1846 ret = -ENOENT; 1847 error_setg(errp, "Bitmap '%s' is not found", 1848 bitmaps->value->u.local); 1849 goto fail; 1850 } 1851 1852 if (readonly && bdrv_is_writable(bs) && 1853 bdrv_dirty_bitmap_enabled(bm)) { 1854 ret = -EINVAL; 1855 error_setg(errp, "Enabled bitmap '%s' incompatible with " 1856 "readonly export", bitmap); 1857 goto fail; 1858 } 1859 break; 1860 case QTYPE_QDICT: 1861 bitmap = bitmaps->value->u.external.name; 1862 bm = block_dirty_bitmap_lookup(bitmaps->value->u.external.node, 1863 bitmap, NULL, errp); 1864 if (!bm) { 1865 ret = -ENOENT; 1866 goto fail; 1867 } 1868 break; 1869 default: 1870 abort(); 1871 } 1872 1873 assert(bm); 1874 1875 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1876 ret = -EINVAL; 1877 goto fail; 1878 } 1879 1880 exp->export_bitmaps[i] = bm; 1881 assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE); 1882 } 1883 1884 /* Mark bitmaps busy in a separate loop, to simplify roll-back concerns. */ 1885 for (i = 0; i < exp->nr_export_bitmaps; i++) { 1886 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true); 1887 } 1888 1889 exp->allocation_depth = arg->allocation_depth; 1890 1891 /* 1892 * We need to inhibit request queuing in the block layer to ensure we can 1893 * be properly quiesced when entering a drained section, as our coroutines 1894 * servicing pending requests might enter blk_pread(). 1895 */ 1896 blk_set_disable_request_queuing(blk, true); 1897 1898 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1899 1900 blk_set_dev_ops(blk, &nbd_block_ops, exp); 1901 1902 QTAILQ_INSERT_TAIL(&exports, exp, next); 1903 1904 bdrv_graph_rdunlock_main_loop(); 1905 1906 return 0; 1907 1908 fail: 1909 bdrv_graph_rdunlock_main_loop(); 1910 g_free(exp->export_bitmaps); 1911 g_free(exp->name); 1912 g_free(exp->description); 1913 return ret; 1914 } 1915 1916 NBDExport *nbd_export_find(const char *name) 1917 { 1918 NBDExport *exp; 1919 QTAILQ_FOREACH(exp, &exports, next) { 1920 if (strcmp(name, exp->name) == 0) { 1921 return exp; 1922 } 1923 } 1924 1925 return NULL; 1926 } 1927 1928 AioContext * 1929 nbd_export_aio_context(NBDExport *exp) 1930 { 1931 return exp->common.ctx; 1932 } 1933 1934 static void nbd_export_request_shutdown(BlockExport *blk_exp) 1935 { 1936 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1937 NBDClient *client, *next; 1938 1939 blk_exp_ref(&exp->common); 1940 /* 1941 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1942 * close mode that stops advertising the export to new clients but 1943 * still permits existing clients to run to completion? Because of 1944 * that possibility, nbd_export_close() can be called more than 1945 * once on an export. 1946 */ 1947 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1948 client_close(client, true); 1949 } 1950 if (exp->name) { 1951 g_free(exp->name); 1952 exp->name = NULL; 1953 QTAILQ_REMOVE(&exports, exp, next); 1954 } 1955 blk_exp_unref(&exp->common); 1956 } 1957 1958 static void nbd_export_delete(BlockExport *blk_exp) 1959 { 1960 size_t i; 1961 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1962 1963 assert(exp->name == NULL); 1964 assert(QTAILQ_EMPTY(&exp->clients)); 1965 1966 g_free(exp->description); 1967 exp->description = NULL; 1968 1969 if (exp->eject_notifier_blk) { 1970 notifier_remove(&exp->eject_notifier); 1971 blk_unref(exp->eject_notifier_blk); 1972 } 1973 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached, 1974 blk_aio_detach, exp); 1975 blk_set_disable_request_queuing(exp->common.blk, false); 1976 1977 for (i = 0; i < exp->nr_export_bitmaps; i++) { 1978 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], false); 1979 } 1980 } 1981 1982 const BlockExportDriver blk_exp_nbd = { 1983 .type = BLOCK_EXPORT_TYPE_NBD, 1984 .instance_size = sizeof(NBDExport), 1985 .create = nbd_export_create, 1986 .delete = nbd_export_delete, 1987 .request_shutdown = nbd_export_request_shutdown, 1988 }; 1989 1990 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1991 unsigned niov, Error **errp) 1992 { 1993 int ret; 1994 1995 g_assert(qemu_in_coroutine()); 1996 qemu_co_mutex_lock(&client->send_lock); 1997 client->send_coroutine = qemu_coroutine_self(); 1998 1999 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 2000 2001 client->send_coroutine = NULL; 2002 qemu_co_mutex_unlock(&client->send_lock); 2003 2004 return ret; 2005 } 2006 2007 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 2008 uint64_t cookie) 2009 { 2010 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 2011 stl_be_p(&reply->error, error); 2012 stq_be_p(&reply->cookie, cookie); 2013 } 2014 2015 static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client, 2016 NBDRequest *request, 2017 uint32_t error, 2018 void *data, 2019 uint64_t len, 2020 Error **errp) 2021 { 2022 NBDSimpleReply reply; 2023 int nbd_err = system_errno_to_nbd_errno(error); 2024 struct iovec iov[] = { 2025 {.iov_base = &reply, .iov_len = sizeof(reply)}, 2026 {.iov_base = data, .iov_len = len} 2027 }; 2028 2029 assert(!len || !nbd_err); 2030 assert(len <= NBD_MAX_BUFFER_SIZE); 2031 assert(client->mode < NBD_MODE_STRUCTURED || 2032 (client->mode == NBD_MODE_STRUCTURED && 2033 request->type != NBD_CMD_READ)); 2034 trace_nbd_co_send_simple_reply(request->cookie, nbd_err, 2035 nbd_err_lookup(nbd_err), len); 2036 set_be_simple_reply(&reply, nbd_err, request->cookie); 2037 2038 return nbd_co_send_iov(client, iov, 2, errp); 2039 } 2040 2041 /* 2042 * Prepare the header of a reply chunk for network transmission. 2043 * 2044 * On input, @iov is partially initialized: iov[0].iov_base must point 2045 * to an uninitialized NBDReply, while the remaining @niov elements 2046 * (if any) must be ready for transmission. This function then 2047 * populates iov[0] for transmission. 2048 */ 2049 static inline void set_be_chunk(NBDClient *client, struct iovec *iov, 2050 size_t niov, uint16_t flags, uint16_t type, 2051 NBDRequest *request) 2052 { 2053 size_t i, length = 0; 2054 2055 for (i = 1; i < niov; i++) { 2056 length += iov[i].iov_len; 2057 } 2058 assert(length <= NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData)); 2059 2060 if (client->mode >= NBD_MODE_EXTENDED) { 2061 NBDExtendedReplyChunk *chunk = iov->iov_base; 2062 2063 iov[0].iov_len = sizeof(*chunk); 2064 stl_be_p(&chunk->magic, NBD_EXTENDED_REPLY_MAGIC); 2065 stw_be_p(&chunk->flags, flags); 2066 stw_be_p(&chunk->type, type); 2067 stq_be_p(&chunk->cookie, request->cookie); 2068 stq_be_p(&chunk->offset, request->from); 2069 stq_be_p(&chunk->length, length); 2070 } else { 2071 NBDStructuredReplyChunk *chunk = iov->iov_base; 2072 2073 iov[0].iov_len = sizeof(*chunk); 2074 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 2075 stw_be_p(&chunk->flags, flags); 2076 stw_be_p(&chunk->type, type); 2077 stq_be_p(&chunk->cookie, request->cookie); 2078 stl_be_p(&chunk->length, length); 2079 } 2080 } 2081 2082 static int coroutine_fn nbd_co_send_chunk_done(NBDClient *client, 2083 NBDRequest *request, 2084 Error **errp) 2085 { 2086 NBDReply hdr; 2087 struct iovec iov[] = { 2088 {.iov_base = &hdr}, 2089 }; 2090 2091 trace_nbd_co_send_chunk_done(request->cookie); 2092 set_be_chunk(client, iov, 1, NBD_REPLY_FLAG_DONE, 2093 NBD_REPLY_TYPE_NONE, request); 2094 return nbd_co_send_iov(client, iov, 1, errp); 2095 } 2096 2097 static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client, 2098 NBDRequest *request, 2099 uint64_t offset, 2100 void *data, 2101 uint64_t size, 2102 bool final, 2103 Error **errp) 2104 { 2105 NBDReply hdr; 2106 NBDStructuredReadData chunk; 2107 struct iovec iov[] = { 2108 {.iov_base = &hdr}, 2109 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2110 {.iov_base = data, .iov_len = size} 2111 }; 2112 2113 assert(size && size <= NBD_MAX_BUFFER_SIZE); 2114 trace_nbd_co_send_chunk_read(request->cookie, offset, data, size); 2115 set_be_chunk(client, iov, 3, final ? NBD_REPLY_FLAG_DONE : 0, 2116 NBD_REPLY_TYPE_OFFSET_DATA, request); 2117 stq_be_p(&chunk.offset, offset); 2118 2119 return nbd_co_send_iov(client, iov, 3, errp); 2120 } 2121 2122 static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client, 2123 NBDRequest *request, 2124 uint32_t error, 2125 const char *msg, 2126 Error **errp) 2127 { 2128 NBDReply hdr; 2129 NBDStructuredError chunk; 2130 int nbd_err = system_errno_to_nbd_errno(error); 2131 struct iovec iov[] = { 2132 {.iov_base = &hdr}, 2133 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2134 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 2135 }; 2136 2137 assert(nbd_err); 2138 trace_nbd_co_send_chunk_error(request->cookie, nbd_err, 2139 nbd_err_lookup(nbd_err), msg ? msg : ""); 2140 set_be_chunk(client, iov, 3, NBD_REPLY_FLAG_DONE, 2141 NBD_REPLY_TYPE_ERROR, request); 2142 stl_be_p(&chunk.error, nbd_err); 2143 stw_be_p(&chunk.message_length, iov[2].iov_len); 2144 2145 return nbd_co_send_iov(client, iov, 3, errp); 2146 } 2147 2148 /* Do a sparse read and send the structured reply to the client. 2149 * Returns -errno if sending fails. blk_co_block_status_above() failure is 2150 * reported to the client, at which point this function succeeds. 2151 */ 2152 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 2153 NBDRequest *request, 2154 uint64_t offset, 2155 uint8_t *data, 2156 uint64_t size, 2157 Error **errp) 2158 { 2159 int ret = 0; 2160 NBDExport *exp = client->exp; 2161 size_t progress = 0; 2162 2163 assert(size <= NBD_MAX_BUFFER_SIZE); 2164 while (progress < size) { 2165 int64_t pnum; 2166 int status = blk_co_block_status_above(exp->common.blk, NULL, 2167 offset + progress, 2168 size - progress, &pnum, NULL, 2169 NULL); 2170 bool final; 2171 2172 if (status < 0) { 2173 char *msg = g_strdup_printf("unable to check for holes: %s", 2174 strerror(-status)); 2175 2176 ret = nbd_co_send_chunk_error(client, request, -status, msg, errp); 2177 g_free(msg); 2178 return ret; 2179 } 2180 assert(pnum && pnum <= size - progress); 2181 final = progress + pnum == size; 2182 if (status & BDRV_BLOCK_ZERO) { 2183 NBDReply hdr; 2184 NBDStructuredReadHole chunk; 2185 struct iovec iov[] = { 2186 {.iov_base = &hdr}, 2187 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2188 }; 2189 2190 trace_nbd_co_send_chunk_read_hole(request->cookie, 2191 offset + progress, pnum); 2192 set_be_chunk(client, iov, 2, 2193 final ? NBD_REPLY_FLAG_DONE : 0, 2194 NBD_REPLY_TYPE_OFFSET_HOLE, request); 2195 stq_be_p(&chunk.offset, offset + progress); 2196 stl_be_p(&chunk.length, pnum); 2197 ret = nbd_co_send_iov(client, iov, 2, errp); 2198 } else { 2199 ret = blk_co_pread(exp->common.blk, offset + progress, pnum, 2200 data + progress, 0); 2201 if (ret < 0) { 2202 error_setg_errno(errp, -ret, "reading from file failed"); 2203 break; 2204 } 2205 ret = nbd_co_send_chunk_read(client, request, offset + progress, 2206 data + progress, pnum, final, errp); 2207 } 2208 2209 if (ret < 0) { 2210 break; 2211 } 2212 progress += pnum; 2213 } 2214 return ret; 2215 } 2216 2217 typedef struct NBDExtentArray { 2218 NBDExtent64 *extents; 2219 unsigned int nb_alloc; 2220 unsigned int count; 2221 uint64_t total_length; 2222 bool extended; 2223 bool can_add; 2224 bool converted_to_be; 2225 } NBDExtentArray; 2226 2227 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc, 2228 NBDMode mode) 2229 { 2230 NBDExtentArray *ea = g_new0(NBDExtentArray, 1); 2231 2232 assert(mode >= NBD_MODE_STRUCTURED); 2233 ea->nb_alloc = nb_alloc; 2234 ea->extents = g_new(NBDExtent64, nb_alloc); 2235 ea->extended = mode >= NBD_MODE_EXTENDED; 2236 ea->can_add = true; 2237 2238 return ea; 2239 } 2240 2241 static void nbd_extent_array_free(NBDExtentArray *ea) 2242 { 2243 g_free(ea->extents); 2244 g_free(ea); 2245 } 2246 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free) 2247 2248 /* Further modifications of the array after conversion are abandoned */ 2249 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea) 2250 { 2251 int i; 2252 2253 assert(!ea->converted_to_be); 2254 assert(ea->extended); 2255 ea->can_add = false; 2256 ea->converted_to_be = true; 2257 2258 for (i = 0; i < ea->count; i++) { 2259 ea->extents[i].length = cpu_to_be64(ea->extents[i].length); 2260 ea->extents[i].flags = cpu_to_be64(ea->extents[i].flags); 2261 } 2262 } 2263 2264 /* Further modifications of the array after conversion are abandoned */ 2265 static NBDExtent32 *nbd_extent_array_convert_to_narrow(NBDExtentArray *ea) 2266 { 2267 int i; 2268 NBDExtent32 *extents = g_new(NBDExtent32, ea->count); 2269 2270 assert(!ea->converted_to_be); 2271 assert(!ea->extended); 2272 ea->can_add = false; 2273 ea->converted_to_be = true; 2274 2275 for (i = 0; i < ea->count; i++) { 2276 assert((ea->extents[i].length | ea->extents[i].flags) <= UINT32_MAX); 2277 extents[i].length = cpu_to_be32(ea->extents[i].length); 2278 extents[i].flags = cpu_to_be32(ea->extents[i].flags); 2279 } 2280 2281 return extents; 2282 } 2283 2284 /* 2285 * Add extent to NBDExtentArray. If extent can't be added (no available space), 2286 * return -1. 2287 * For safety, when returning -1 for the first time, .can_add is set to false, 2288 * and further calls to nbd_extent_array_add() will crash. 2289 * (this avoids the situation where a caller ignores failure to add one extent, 2290 * where adding another extent that would squash into the last array entry 2291 * would result in an incorrect range reported to the client) 2292 */ 2293 static int nbd_extent_array_add(NBDExtentArray *ea, 2294 uint64_t length, uint32_t flags) 2295 { 2296 assert(ea->can_add); 2297 2298 if (!length) { 2299 return 0; 2300 } 2301 if (!ea->extended) { 2302 assert(length <= UINT32_MAX); 2303 } 2304 2305 /* Extend previous extent if flags are the same */ 2306 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) { 2307 uint64_t sum = length + ea->extents[ea->count - 1].length; 2308 2309 /* 2310 * sum cannot overflow: the block layer bounds image size at 2311 * 2^63, and ea->extents[].length comes from the block layer. 2312 */ 2313 assert(sum >= length); 2314 if (sum <= UINT32_MAX || ea->extended) { 2315 ea->extents[ea->count - 1].length = sum; 2316 ea->total_length += length; 2317 return 0; 2318 } 2319 } 2320 2321 if (ea->count >= ea->nb_alloc) { 2322 ea->can_add = false; 2323 return -1; 2324 } 2325 2326 ea->total_length += length; 2327 ea->extents[ea->count] = (NBDExtent64) {.length = length, .flags = flags}; 2328 ea->count++; 2329 2330 return 0; 2331 } 2332 2333 static int coroutine_fn blockstatus_to_extents(BlockBackend *blk, 2334 uint64_t offset, uint64_t bytes, 2335 NBDExtentArray *ea) 2336 { 2337 while (bytes) { 2338 uint32_t flags; 2339 int64_t num; 2340 int ret = blk_co_block_status_above(blk, NULL, offset, bytes, &num, 2341 NULL, NULL); 2342 2343 if (ret < 0) { 2344 return ret; 2345 } 2346 2347 flags = (ret & BDRV_BLOCK_DATA ? 0 : NBD_STATE_HOLE) | 2348 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 2349 2350 if (nbd_extent_array_add(ea, num, flags) < 0) { 2351 return 0; 2352 } 2353 2354 offset += num; 2355 bytes -= num; 2356 } 2357 2358 return 0; 2359 } 2360 2361 static int coroutine_fn blockalloc_to_extents(BlockBackend *blk, 2362 uint64_t offset, uint64_t bytes, 2363 NBDExtentArray *ea) 2364 { 2365 while (bytes) { 2366 int64_t num; 2367 int ret = blk_co_is_allocated_above(blk, NULL, false, offset, bytes, 2368 &num); 2369 2370 if (ret < 0) { 2371 return ret; 2372 } 2373 2374 if (nbd_extent_array_add(ea, num, ret) < 0) { 2375 return 0; 2376 } 2377 2378 offset += num; 2379 bytes -= num; 2380 } 2381 2382 return 0; 2383 } 2384 2385 /* 2386 * nbd_co_send_extents 2387 * 2388 * @ea is converted to BE by the function 2389 * @last controls whether NBD_REPLY_FLAG_DONE is sent. 2390 */ 2391 static int coroutine_fn 2392 nbd_co_send_extents(NBDClient *client, NBDRequest *request, NBDExtentArray *ea, 2393 bool last, uint32_t context_id, Error **errp) 2394 { 2395 NBDReply hdr; 2396 NBDStructuredMeta meta; 2397 NBDExtendedMeta meta_ext; 2398 g_autofree NBDExtent32 *extents = NULL; 2399 uint16_t type; 2400 struct iovec iov[] = { {.iov_base = &hdr}, {0}, {0} }; 2401 2402 if (client->mode >= NBD_MODE_EXTENDED) { 2403 type = NBD_REPLY_TYPE_BLOCK_STATUS_EXT; 2404 2405 iov[1].iov_base = &meta_ext; 2406 iov[1].iov_len = sizeof(meta_ext); 2407 stl_be_p(&meta_ext.context_id, context_id); 2408 stl_be_p(&meta_ext.count, ea->count); 2409 2410 nbd_extent_array_convert_to_be(ea); 2411 iov[2].iov_base = ea->extents; 2412 iov[2].iov_len = ea->count * sizeof(ea->extents[0]); 2413 } else { 2414 type = NBD_REPLY_TYPE_BLOCK_STATUS; 2415 2416 iov[1].iov_base = &meta; 2417 iov[1].iov_len = sizeof(meta); 2418 stl_be_p(&meta.context_id, context_id); 2419 2420 extents = nbd_extent_array_convert_to_narrow(ea); 2421 iov[2].iov_base = extents; 2422 iov[2].iov_len = ea->count * sizeof(extents[0]); 2423 } 2424 2425 trace_nbd_co_send_extents(request->cookie, ea->count, context_id, 2426 ea->total_length, last); 2427 set_be_chunk(client, iov, 3, last ? NBD_REPLY_FLAG_DONE : 0, type, 2428 request); 2429 2430 return nbd_co_send_iov(client, iov, 3, errp); 2431 } 2432 2433 /* Get block status from the exported device and send it to the client */ 2434 static int 2435 coroutine_fn nbd_co_send_block_status(NBDClient *client, NBDRequest *request, 2436 BlockBackend *blk, uint64_t offset, 2437 uint64_t length, bool dont_fragment, 2438 bool last, uint32_t context_id, 2439 Error **errp) 2440 { 2441 int ret; 2442 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2443 g_autoptr(NBDExtentArray) ea = 2444 nbd_extent_array_new(nb_extents, client->mode); 2445 2446 if (context_id == NBD_META_ID_BASE_ALLOCATION) { 2447 ret = blockstatus_to_extents(blk, offset, length, ea); 2448 } else { 2449 ret = blockalloc_to_extents(blk, offset, length, ea); 2450 } 2451 if (ret < 0) { 2452 return nbd_co_send_chunk_error(client, request, -ret, 2453 "can't get block status", errp); 2454 } 2455 2456 return nbd_co_send_extents(client, request, ea, last, context_id, errp); 2457 } 2458 2459 /* Populate @ea from a dirty bitmap. */ 2460 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap, 2461 uint64_t offset, uint64_t length, 2462 NBDExtentArray *es) 2463 { 2464 int64_t start, dirty_start, dirty_count; 2465 int64_t end = offset + length; 2466 bool full = false; 2467 int64_t bound = es->extended ? INT64_MAX : INT32_MAX; 2468 2469 bdrv_dirty_bitmap_lock(bitmap); 2470 2471 for (start = offset; 2472 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, bound, 2473 &dirty_start, &dirty_count); 2474 start = dirty_start + dirty_count) 2475 { 2476 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) || 2477 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0)) 2478 { 2479 full = true; 2480 break; 2481 } 2482 } 2483 2484 if (!full) { 2485 /* last non dirty extent, nothing to do if array is now full */ 2486 (void) nbd_extent_array_add(es, end - start, 0); 2487 } 2488 2489 bdrv_dirty_bitmap_unlock(bitmap); 2490 } 2491 2492 static int coroutine_fn nbd_co_send_bitmap(NBDClient *client, 2493 NBDRequest *request, 2494 BdrvDirtyBitmap *bitmap, 2495 uint64_t offset, 2496 uint64_t length, bool dont_fragment, 2497 bool last, uint32_t context_id, 2498 Error **errp) 2499 { 2500 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2501 g_autoptr(NBDExtentArray) ea = 2502 nbd_extent_array_new(nb_extents, client->mode); 2503 2504 bitmap_to_extents(bitmap, offset, length, ea); 2505 2506 return nbd_co_send_extents(client, request, ea, last, context_id, errp); 2507 } 2508 2509 /* 2510 * nbd_co_block_status_payload_read 2511 * Called when a client wants a subset of negotiated contexts via a 2512 * BLOCK_STATUS payload. Check the payload for valid length and 2513 * contents. On success, return 0 with request updated to effective 2514 * length. If request was invalid but all payload consumed, return 0 2515 * with request->len and request->contexts->count set to 0 (which will 2516 * trigger an appropriate NBD_EINVAL response later on). Return 2517 * negative errno if the payload was not fully consumed. 2518 */ 2519 static int 2520 nbd_co_block_status_payload_read(NBDClient *client, NBDRequest *request, 2521 Error **errp) 2522 { 2523 uint64_t payload_len = request->len; 2524 g_autofree char *buf = NULL; 2525 size_t count, i, nr_bitmaps; 2526 uint32_t id; 2527 2528 if (payload_len > NBD_MAX_BUFFER_SIZE) { 2529 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)", 2530 request->len, NBD_MAX_BUFFER_SIZE); 2531 return -EINVAL; 2532 } 2533 2534 assert(client->contexts.exp == client->exp); 2535 nr_bitmaps = client->exp->nr_export_bitmaps; 2536 request->contexts = g_new0(NBDMetaContexts, 1); 2537 request->contexts->exp = client->exp; 2538 2539 if (payload_len % sizeof(uint32_t) || 2540 payload_len < sizeof(NBDBlockStatusPayload) || 2541 payload_len > (sizeof(NBDBlockStatusPayload) + 2542 sizeof(id) * client->contexts.count)) { 2543 goto skip; 2544 } 2545 2546 buf = g_malloc(payload_len); 2547 if (nbd_read(client->ioc, buf, payload_len, 2548 "CMD_BLOCK_STATUS data", errp) < 0) { 2549 return -EIO; 2550 } 2551 trace_nbd_co_receive_request_payload_received(request->cookie, 2552 payload_len); 2553 request->contexts->bitmaps = g_new0(bool, nr_bitmaps); 2554 count = (payload_len - sizeof(NBDBlockStatusPayload)) / sizeof(id); 2555 payload_len = 0; 2556 2557 for (i = 0; i < count; i++) { 2558 id = ldl_be_p(buf + sizeof(NBDBlockStatusPayload) + sizeof(id) * i); 2559 if (id == NBD_META_ID_BASE_ALLOCATION) { 2560 if (!client->contexts.base_allocation || 2561 request->contexts->base_allocation) { 2562 goto skip; 2563 } 2564 request->contexts->base_allocation = true; 2565 } else if (id == NBD_META_ID_ALLOCATION_DEPTH) { 2566 if (!client->contexts.allocation_depth || 2567 request->contexts->allocation_depth) { 2568 goto skip; 2569 } 2570 request->contexts->allocation_depth = true; 2571 } else { 2572 unsigned idx = id - NBD_META_ID_DIRTY_BITMAP; 2573 2574 if (idx >= nr_bitmaps || !client->contexts.bitmaps[idx] || 2575 request->contexts->bitmaps[idx]) { 2576 goto skip; 2577 } 2578 request->contexts->bitmaps[idx] = true; 2579 } 2580 } 2581 2582 request->len = ldq_be_p(buf); 2583 request->contexts->count = count; 2584 return 0; 2585 2586 skip: 2587 trace_nbd_co_receive_block_status_payload_compliance(request->from, 2588 request->len); 2589 request->len = request->contexts->count = 0; 2590 return nbd_drop(client->ioc, payload_len, errp); 2591 } 2592 2593 /* nbd_co_receive_request 2594 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2595 * connection right away, -EAGAIN to indicate we were interrupted and the 2596 * channel should be quiesced, and any other negative value to report an error 2597 * to the client (although the caller may still need to disconnect after 2598 * reporting the error). 2599 */ 2600 static int coroutine_fn nbd_co_receive_request(NBDRequestData *req, 2601 NBDRequest *request, 2602 Error **errp) 2603 { 2604 NBDClient *client = req->client; 2605 bool extended_with_payload; 2606 bool check_length = false; 2607 bool check_rofs = false; 2608 bool allocate_buffer = false; 2609 bool payload_okay = false; 2610 uint64_t payload_len = 0; 2611 int valid_flags = NBD_CMD_FLAG_FUA; 2612 int ret; 2613 2614 g_assert(qemu_in_coroutine()); 2615 ret = nbd_receive_request(client, request, errp); 2616 if (ret < 0) { 2617 return ret; 2618 } 2619 2620 trace_nbd_co_receive_request_decode_type(request->cookie, request->type, 2621 nbd_cmd_lookup(request->type)); 2622 extended_with_payload = client->mode >= NBD_MODE_EXTENDED && 2623 request->flags & NBD_CMD_FLAG_PAYLOAD_LEN; 2624 if (extended_with_payload) { 2625 payload_len = request->len; 2626 check_length = true; 2627 } 2628 2629 switch (request->type) { 2630 case NBD_CMD_DISC: 2631 /* Special case: we're going to disconnect without a reply, 2632 * whether or not flags, from, or len are bogus */ 2633 req->complete = true; 2634 return -EIO; 2635 2636 case NBD_CMD_READ: 2637 if (client->mode >= NBD_MODE_STRUCTURED) { 2638 valid_flags |= NBD_CMD_FLAG_DF; 2639 } 2640 check_length = true; 2641 allocate_buffer = true; 2642 break; 2643 2644 case NBD_CMD_WRITE: 2645 if (client->mode >= NBD_MODE_EXTENDED) { 2646 if (!extended_with_payload) { 2647 /* The client is noncompliant. Trace it, but proceed. */ 2648 trace_nbd_co_receive_ext_payload_compliance(request->from, 2649 request->len); 2650 } 2651 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN; 2652 } 2653 payload_okay = true; 2654 payload_len = request->len; 2655 check_length = true; 2656 allocate_buffer = true; 2657 check_rofs = true; 2658 break; 2659 2660 case NBD_CMD_FLUSH: 2661 break; 2662 2663 case NBD_CMD_TRIM: 2664 check_rofs = true; 2665 break; 2666 2667 case NBD_CMD_CACHE: 2668 check_length = true; 2669 break; 2670 2671 case NBD_CMD_WRITE_ZEROES: 2672 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2673 check_rofs = true; 2674 break; 2675 2676 case NBD_CMD_BLOCK_STATUS: 2677 if (extended_with_payload) { 2678 ret = nbd_co_block_status_payload_read(client, request, errp); 2679 if (ret < 0) { 2680 return ret; 2681 } 2682 /* payload now consumed */ 2683 check_length = false; 2684 payload_len = 0; 2685 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN; 2686 } else { 2687 request->contexts = &client->contexts; 2688 } 2689 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2690 break; 2691 2692 default: 2693 /* Unrecognized, will fail later */ 2694 ; 2695 } 2696 2697 /* Payload and buffer handling. */ 2698 if (!payload_len) { 2699 req->complete = true; 2700 } 2701 if (check_length && request->len > NBD_MAX_BUFFER_SIZE) { 2702 /* READ, WRITE, CACHE */ 2703 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)", 2704 request->len, NBD_MAX_BUFFER_SIZE); 2705 return -EINVAL; 2706 } 2707 if (payload_len && !payload_okay) { 2708 /* 2709 * For now, we don't support payloads on other commands; but 2710 * we can keep the connection alive by ignoring the payload. 2711 * We will fail the command later with NBD_EINVAL for the use 2712 * of an unsupported flag (and not for access beyond bounds). 2713 */ 2714 assert(request->type != NBD_CMD_WRITE); 2715 request->len = 0; 2716 } 2717 if (allocate_buffer) { 2718 /* READ, WRITE */ 2719 req->data = blk_try_blockalign(client->exp->common.blk, 2720 request->len); 2721 if (req->data == NULL) { 2722 error_setg(errp, "No memory"); 2723 return -ENOMEM; 2724 } 2725 } 2726 if (payload_len) { 2727 if (payload_okay) { 2728 /* WRITE */ 2729 assert(req->data); 2730 ret = nbd_read(client->ioc, req->data, payload_len, 2731 "CMD_WRITE data", errp); 2732 } else { 2733 ret = nbd_drop(client->ioc, payload_len, errp); 2734 } 2735 if (ret < 0) { 2736 return -EIO; 2737 } 2738 req->complete = true; 2739 trace_nbd_co_receive_request_payload_received(request->cookie, 2740 payload_len); 2741 } 2742 2743 /* Sanity checks. */ 2744 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && check_rofs) { 2745 /* WRITE, TRIM, WRITE_ZEROES */ 2746 error_setg(errp, "Export is read-only"); 2747 return -EROFS; 2748 } 2749 if (request->from > client->exp->size || 2750 request->len > client->exp->size - request->from) { 2751 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu64 2752 ", Size: %" PRIu64, request->from, request->len, 2753 client->exp->size); 2754 return (request->type == NBD_CMD_WRITE || 2755 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2756 } 2757 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2758 client->check_align)) { 2759 /* 2760 * The block layer gracefully handles unaligned requests, but 2761 * it's still worth tracing client non-compliance 2762 */ 2763 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2764 request->from, 2765 request->len, 2766 client->check_align); 2767 } 2768 if (request->flags & ~valid_flags) { 2769 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2770 nbd_cmd_lookup(request->type), request->flags); 2771 return -EINVAL; 2772 } 2773 2774 return 0; 2775 } 2776 2777 /* Send simple reply without a payload, or a structured error 2778 * @error_msg is ignored if @ret >= 0 2779 * Returns 0 if connection is still live, -errno on failure to talk to client 2780 */ 2781 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2782 NBDRequest *request, 2783 int ret, 2784 const char *error_msg, 2785 Error **errp) 2786 { 2787 if (client->mode >= NBD_MODE_STRUCTURED && ret < 0) { 2788 return nbd_co_send_chunk_error(client, request, -ret, error_msg, errp); 2789 } else if (client->mode >= NBD_MODE_EXTENDED) { 2790 return nbd_co_send_chunk_done(client, request, errp); 2791 } else { 2792 return nbd_co_send_simple_reply(client, request, ret < 0 ? -ret : 0, 2793 NULL, 0, errp); 2794 } 2795 } 2796 2797 /* Handle NBD_CMD_READ request. 2798 * Return -errno if sending fails. Other errors are reported directly to the 2799 * client as an error reply. */ 2800 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2801 uint8_t *data, Error **errp) 2802 { 2803 int ret; 2804 NBDExport *exp = client->exp; 2805 2806 assert(request->type == NBD_CMD_READ); 2807 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2808 2809 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2810 if (request->flags & NBD_CMD_FLAG_FUA) { 2811 ret = blk_co_flush(exp->common.blk); 2812 if (ret < 0) { 2813 return nbd_send_generic_reply(client, request, ret, 2814 "flush failed", errp); 2815 } 2816 } 2817 2818 if (client->mode >= NBD_MODE_STRUCTURED && 2819 !(request->flags & NBD_CMD_FLAG_DF) && request->len) 2820 { 2821 return nbd_co_send_sparse_read(client, request, request->from, 2822 data, request->len, errp); 2823 } 2824 2825 ret = blk_co_pread(exp->common.blk, request->from, request->len, data, 0); 2826 if (ret < 0) { 2827 return nbd_send_generic_reply(client, request, ret, 2828 "reading from file failed", errp); 2829 } 2830 2831 if (client->mode >= NBD_MODE_STRUCTURED) { 2832 if (request->len) { 2833 return nbd_co_send_chunk_read(client, request, request->from, data, 2834 request->len, true, errp); 2835 } else { 2836 return nbd_co_send_chunk_done(client, request, errp); 2837 } 2838 } else { 2839 return nbd_co_send_simple_reply(client, request, 0, 2840 data, request->len, errp); 2841 } 2842 } 2843 2844 /* 2845 * nbd_do_cmd_cache 2846 * 2847 * Handle NBD_CMD_CACHE request. 2848 * Return -errno if sending fails. Other errors are reported directly to the 2849 * client as an error reply. 2850 */ 2851 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2852 Error **errp) 2853 { 2854 int ret; 2855 NBDExport *exp = client->exp; 2856 2857 assert(request->type == NBD_CMD_CACHE); 2858 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2859 2860 ret = blk_co_preadv(exp->common.blk, request->from, request->len, 2861 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2862 2863 return nbd_send_generic_reply(client, request, ret, 2864 "caching data failed", errp); 2865 } 2866 2867 /* Handle NBD request. 2868 * Return -errno if sending fails. Other errors are reported directly to the 2869 * client as an error reply. */ 2870 static coroutine_fn int nbd_handle_request(NBDClient *client, 2871 NBDRequest *request, 2872 uint8_t *data, Error **errp) 2873 { 2874 int ret; 2875 int flags; 2876 NBDExport *exp = client->exp; 2877 char *msg; 2878 size_t i; 2879 2880 switch (request->type) { 2881 case NBD_CMD_CACHE: 2882 return nbd_do_cmd_cache(client, request, errp); 2883 2884 case NBD_CMD_READ: 2885 return nbd_do_cmd_read(client, request, data, errp); 2886 2887 case NBD_CMD_WRITE: 2888 flags = 0; 2889 if (request->flags & NBD_CMD_FLAG_FUA) { 2890 flags |= BDRV_REQ_FUA; 2891 } 2892 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2893 ret = blk_co_pwrite(exp->common.blk, request->from, request->len, data, 2894 flags); 2895 return nbd_send_generic_reply(client, request, ret, 2896 "writing to file failed", errp); 2897 2898 case NBD_CMD_WRITE_ZEROES: 2899 flags = 0; 2900 if (request->flags & NBD_CMD_FLAG_FUA) { 2901 flags |= BDRV_REQ_FUA; 2902 } 2903 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2904 flags |= BDRV_REQ_MAY_UNMAP; 2905 } 2906 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2907 flags |= BDRV_REQ_NO_FALLBACK; 2908 } 2909 ret = blk_co_pwrite_zeroes(exp->common.blk, request->from, request->len, 2910 flags); 2911 return nbd_send_generic_reply(client, request, ret, 2912 "writing to file failed", errp); 2913 2914 case NBD_CMD_DISC: 2915 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2916 abort(); 2917 2918 case NBD_CMD_FLUSH: 2919 ret = blk_co_flush(exp->common.blk); 2920 return nbd_send_generic_reply(client, request, ret, 2921 "flush failed", errp); 2922 2923 case NBD_CMD_TRIM: 2924 ret = blk_co_pdiscard(exp->common.blk, request->from, request->len); 2925 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) { 2926 ret = blk_co_flush(exp->common.blk); 2927 } 2928 return nbd_send_generic_reply(client, request, ret, 2929 "discard failed", errp); 2930 2931 case NBD_CMD_BLOCK_STATUS: 2932 assert(request->contexts); 2933 assert(client->mode >= NBD_MODE_EXTENDED || 2934 request->len <= UINT32_MAX); 2935 if (request->contexts->count) { 2936 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2937 int contexts_remaining = request->contexts->count; 2938 2939 if (!request->len) { 2940 return nbd_send_generic_reply(client, request, -EINVAL, 2941 "need non-zero length", errp); 2942 } 2943 if (request->contexts->base_allocation) { 2944 ret = nbd_co_send_block_status(client, request, 2945 exp->common.blk, 2946 request->from, 2947 request->len, dont_fragment, 2948 !--contexts_remaining, 2949 NBD_META_ID_BASE_ALLOCATION, 2950 errp); 2951 if (ret < 0) { 2952 return ret; 2953 } 2954 } 2955 2956 if (request->contexts->allocation_depth) { 2957 ret = nbd_co_send_block_status(client, request, 2958 exp->common.blk, 2959 request->from, request->len, 2960 dont_fragment, 2961 !--contexts_remaining, 2962 NBD_META_ID_ALLOCATION_DEPTH, 2963 errp); 2964 if (ret < 0) { 2965 return ret; 2966 } 2967 } 2968 2969 assert(request->contexts->exp == client->exp); 2970 for (i = 0; i < client->exp->nr_export_bitmaps; i++) { 2971 if (!request->contexts->bitmaps[i]) { 2972 continue; 2973 } 2974 ret = nbd_co_send_bitmap(client, request, 2975 client->exp->export_bitmaps[i], 2976 request->from, request->len, 2977 dont_fragment, !--contexts_remaining, 2978 NBD_META_ID_DIRTY_BITMAP + i, errp); 2979 if (ret < 0) { 2980 return ret; 2981 } 2982 } 2983 2984 assert(!contexts_remaining); 2985 2986 return 0; 2987 } else if (client->contexts.count) { 2988 return nbd_send_generic_reply(client, request, -EINVAL, 2989 "CMD_BLOCK_STATUS payload not valid", 2990 errp); 2991 } else { 2992 return nbd_send_generic_reply(client, request, -EINVAL, 2993 "CMD_BLOCK_STATUS not negotiated", 2994 errp); 2995 } 2996 2997 default: 2998 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2999 request->type); 3000 ret = nbd_send_generic_reply(client, request, -EINVAL, msg, 3001 errp); 3002 g_free(msg); 3003 return ret; 3004 } 3005 } 3006 3007 /* Owns a reference to the NBDClient passed as opaque. */ 3008 static coroutine_fn void nbd_trip(void *opaque) 3009 { 3010 NBDClient *client = opaque; 3011 NBDRequestData *req = NULL; 3012 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 3013 int ret; 3014 Error *local_err = NULL; 3015 3016 /* 3017 * Note that nbd_client_put() and client_close() must be called from the 3018 * main loop thread. Use aio_co_reschedule_self() to switch AioContext 3019 * before calling these functions. 3020 */ 3021 3022 trace_nbd_trip(); 3023 3024 qemu_mutex_lock(&client->lock); 3025 3026 if (client->closing) { 3027 goto done; 3028 } 3029 3030 if (client->quiescing) { 3031 /* 3032 * We're switching between AIO contexts. Don't attempt to receive a new 3033 * request and kick the main context which may be waiting for us. 3034 */ 3035 client->recv_coroutine = NULL; 3036 aio_wait_kick(); 3037 goto done; 3038 } 3039 3040 req = nbd_request_get(client); 3041 3042 /* 3043 * nbd_co_receive_request() returns -EAGAIN when nbd_drained_begin() has 3044 * set client->quiescing but by the time we get back nbd_drained_end() may 3045 * have already cleared client->quiescing. In that case we try again 3046 * because nothing else will spawn an nbd_trip() coroutine until we set 3047 * client->recv_coroutine = NULL further down. 3048 */ 3049 do { 3050 assert(client->recv_coroutine == qemu_coroutine_self()); 3051 qemu_mutex_unlock(&client->lock); 3052 ret = nbd_co_receive_request(req, &request, &local_err); 3053 qemu_mutex_lock(&client->lock); 3054 } while (ret == -EAGAIN && !client->quiescing); 3055 3056 client->recv_coroutine = NULL; 3057 3058 if (client->closing) { 3059 /* 3060 * The client may be closed when we are blocked in 3061 * nbd_co_receive_request() 3062 */ 3063 goto done; 3064 } 3065 3066 if (ret == -EAGAIN) { 3067 goto done; 3068 } 3069 3070 nbd_client_receive_next_request(client); 3071 3072 if (ret == -EIO) { 3073 goto disconnect; 3074 } 3075 3076 qemu_mutex_unlock(&client->lock); 3077 qio_channel_set_cork(client->ioc, true); 3078 3079 if (ret < 0) { 3080 /* It wasn't -EIO, so, according to nbd_co_receive_request() 3081 * semantics, we should return the error to the client. */ 3082 Error *export_err = local_err; 3083 3084 local_err = NULL; 3085 ret = nbd_send_generic_reply(client, &request, -EINVAL, 3086 error_get_pretty(export_err), &local_err); 3087 error_free(export_err); 3088 } else { 3089 ret = nbd_handle_request(client, &request, req->data, &local_err); 3090 } 3091 if (request.contexts && request.contexts != &client->contexts) { 3092 assert(request.type == NBD_CMD_BLOCK_STATUS); 3093 g_free(request.contexts->bitmaps); 3094 g_free(request.contexts); 3095 } 3096 3097 qio_channel_set_cork(client->ioc, false); 3098 qemu_mutex_lock(&client->lock); 3099 3100 if (ret < 0) { 3101 error_prepend(&local_err, "Failed to send reply: "); 3102 goto disconnect; 3103 } 3104 3105 /* 3106 * We must disconnect after NBD_CMD_WRITE or BLOCK_STATUS with 3107 * payload if we did not read the payload. 3108 */ 3109 if (!req->complete) { 3110 error_setg(&local_err, "Request handling failed in intermediate state"); 3111 goto disconnect; 3112 } 3113 3114 done: 3115 if (req) { 3116 nbd_request_put(req); 3117 } 3118 3119 qemu_mutex_unlock(&client->lock); 3120 3121 if (!nbd_client_put_nonzero(client)) { 3122 aio_co_reschedule_self(qemu_get_aio_context()); 3123 nbd_client_put(client); 3124 } 3125 return; 3126 3127 disconnect: 3128 if (local_err) { 3129 error_reportf_err(local_err, "Disconnect client, due to: "); 3130 } 3131 3132 nbd_request_put(req); 3133 qemu_mutex_unlock(&client->lock); 3134 3135 aio_co_reschedule_self(qemu_get_aio_context()); 3136 client_close(client, true); 3137 nbd_client_put(client); 3138 } 3139 3140 /* 3141 * Runs in export AioContext and main loop thread. Caller must hold 3142 * client->lock. 3143 */ 3144 static void nbd_client_receive_next_request(NBDClient *client) 3145 { 3146 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS && 3147 !client->quiescing) { 3148 nbd_client_get(client); 3149 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 3150 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine); 3151 } 3152 } 3153 3154 static coroutine_fn void nbd_co_client_start(void *opaque) 3155 { 3156 NBDClient *client = opaque; 3157 Error *local_err = NULL; 3158 3159 qemu_co_mutex_init(&client->send_lock); 3160 3161 if (nbd_negotiate(client, &local_err)) { 3162 if (local_err) { 3163 error_report_err(local_err); 3164 } 3165 client_close(client, false); 3166 return; 3167 } 3168 3169 WITH_QEMU_LOCK_GUARD(&client->lock) { 3170 nbd_client_receive_next_request(client); 3171 } 3172 } 3173 3174 /* 3175 * Create a new client listener using the given channel @sioc. 3176 * Begin servicing it in a coroutine. When the connection closes, call 3177 * @close_fn with an indication of whether the client completed negotiation. 3178 */ 3179 void nbd_client_new(QIOChannelSocket *sioc, 3180 QCryptoTLSCreds *tlscreds, 3181 const char *tlsauthz, 3182 void (*close_fn)(NBDClient *, bool)) 3183 { 3184 NBDClient *client; 3185 Coroutine *co; 3186 3187 client = g_new0(NBDClient, 1); 3188 qemu_mutex_init(&client->lock); 3189 client->refcount = 1; 3190 client->tlscreds = tlscreds; 3191 if (tlscreds) { 3192 object_ref(OBJECT(client->tlscreds)); 3193 } 3194 client->tlsauthz = g_strdup(tlsauthz); 3195 client->sioc = sioc; 3196 qio_channel_set_delay(QIO_CHANNEL(sioc), false); 3197 object_ref(OBJECT(client->sioc)); 3198 client->ioc = QIO_CHANNEL(sioc); 3199 object_ref(OBJECT(client->ioc)); 3200 client->close_fn = close_fn; 3201 3202 co = qemu_coroutine_create(nbd_co_client_start, client); 3203 qemu_coroutine_enter(co); 3204 } 3205