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 void *owner; 128 129 QemuMutex lock; 130 131 NBDExport *exp; 132 QCryptoTLSCreds *tlscreds; 133 char *tlsauthz; 134 uint32_t handshake_max_secs; 135 QIOChannelSocket *sioc; /* The underlying data channel */ 136 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 137 138 Coroutine *recv_coroutine; /* protected by lock */ 139 140 CoMutex send_lock; 141 Coroutine *send_coroutine; 142 143 bool read_yielding; /* protected by lock */ 144 bool quiescing; /* protected by lock */ 145 146 QTAILQ_ENTRY(NBDClient) next; 147 int nb_requests; /* protected by lock */ 148 bool closing; /* protected by lock */ 149 150 uint32_t check_align; /* If non-zero, check for aligned client requests */ 151 152 NBDMode mode; 153 NBDMetaContexts contexts; /* Negotiated meta contexts */ 154 155 uint32_t opt; /* Current option being negotiated */ 156 uint32_t optlen; /* remaining length of data in ioc for the option being 157 negotiated now */ 158 }; 159 160 static void nbd_client_receive_next_request(NBDClient *client); 161 162 /* Basic flow for negotiation 163 164 Server Client 165 Negotiate 166 167 or 168 169 Server Client 170 Negotiate #1 171 Option 172 Negotiate #2 173 174 ---- 175 176 followed by 177 178 Server Client 179 Request 180 Response 181 Request 182 Response 183 ... 184 ... 185 Request (type == 2) 186 187 */ 188 189 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 190 uint32_t type, uint32_t length) 191 { 192 stq_be_p(&rep->magic, NBD_REP_MAGIC); 193 stl_be_p(&rep->option, option); 194 stl_be_p(&rep->type, type); 195 stl_be_p(&rep->length, length); 196 } 197 198 /* Send a reply header, including length, but no payload. 199 * Return -errno on error, 0 on success. */ 200 static coroutine_fn int 201 nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 202 uint32_t len, Error **errp) 203 { 204 NBDOptionReply rep; 205 206 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 207 type, nbd_rep_lookup(type), len); 208 209 assert(len < NBD_MAX_BUFFER_SIZE); 210 211 set_be_option_rep(&rep, client->opt, type, len); 212 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 213 } 214 215 /* Send a reply header with default 0 length. 216 * Return -errno on error, 0 on success. */ 217 static coroutine_fn int 218 nbd_negotiate_send_rep(NBDClient *client, uint32_t type, Error **errp) 219 { 220 return nbd_negotiate_send_rep_len(client, type, 0, errp); 221 } 222 223 /* Send an error reply. 224 * Return -errno on error, 0 on success. */ 225 static coroutine_fn int G_GNUC_PRINTF(4, 0) 226 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 227 Error **errp, const char *fmt, va_list va) 228 { 229 ERRP_GUARD(); 230 g_autofree char *msg = NULL; 231 int ret; 232 size_t len; 233 234 msg = g_strdup_vprintf(fmt, va); 235 len = strlen(msg); 236 assert(len < NBD_MAX_STRING_SIZE); 237 trace_nbd_negotiate_send_rep_err(msg); 238 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 239 if (ret < 0) { 240 return ret; 241 } 242 if (nbd_write(client->ioc, msg, len, errp) < 0) { 243 error_prepend(errp, "write failed (error message): "); 244 return -EIO; 245 } 246 247 return 0; 248 } 249 250 /* 251 * Return a malloc'd copy of @name suitable for use in an error reply. 252 */ 253 static char * 254 nbd_sanitize_name(const char *name) 255 { 256 if (strnlen(name, 80) < 80) { 257 return g_strdup(name); 258 } 259 /* XXX Should we also try to sanitize any control characters? */ 260 return g_strdup_printf("%.80s...", name); 261 } 262 263 /* Send an error reply. 264 * Return -errno on error, 0 on success. */ 265 static coroutine_fn int G_GNUC_PRINTF(4, 5) 266 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 267 Error **errp, const char *fmt, ...) 268 { 269 va_list va; 270 int ret; 271 272 va_start(va, fmt); 273 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 274 va_end(va); 275 return ret; 276 } 277 278 /* Drop remainder of the current option, and send a reply with the 279 * given error type and message. Return -errno on read or write 280 * failure; or 0 if connection is still live. */ 281 static coroutine_fn int G_GNUC_PRINTF(4, 0) 282 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 283 const char *fmt, va_list va) 284 { 285 int ret = nbd_drop(client->ioc, client->optlen, errp); 286 287 client->optlen = 0; 288 if (!ret) { 289 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 290 } 291 return ret; 292 } 293 294 static coroutine_fn int G_GNUC_PRINTF(4, 5) 295 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 296 const char *fmt, ...) 297 { 298 int ret; 299 va_list va; 300 301 va_start(va, fmt); 302 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 303 va_end(va); 304 305 return ret; 306 } 307 308 static coroutine_fn int G_GNUC_PRINTF(3, 4) 309 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 310 { 311 int ret; 312 va_list va; 313 314 va_start(va, fmt); 315 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 316 va_end(va); 317 318 return ret; 319 } 320 321 /* Read size bytes from the unparsed payload of the current option. 322 * If @check_nul, require that no NUL bytes appear in buffer. 323 * Return -errno on I/O error, 0 if option was completely handled by 324 * sending a reply about inconsistent lengths, or 1 on success. */ 325 static coroutine_fn int 326 nbd_opt_read(NBDClient *client, void *buffer, size_t size, 327 bool check_nul, Error **errp) 328 { 329 if (size > client->optlen) { 330 return nbd_opt_invalid(client, errp, 331 "Inconsistent lengths in option %s", 332 nbd_opt_lookup(client->opt)); 333 } 334 client->optlen -= size; 335 if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) { 336 return -EIO; 337 } 338 339 if (check_nul && strnlen(buffer, size) != size) { 340 return nbd_opt_invalid(client, errp, 341 "Unexpected embedded NUL in option %s", 342 nbd_opt_lookup(client->opt)); 343 } 344 return 1; 345 } 346 347 /* Drop size bytes from the unparsed payload of the current option. 348 * Return -errno on I/O error, 0 if option was completely handled by 349 * sending a reply about inconsistent lengths, or 1 on success. */ 350 static coroutine_fn int 351 nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 352 { 353 if (size > client->optlen) { 354 return nbd_opt_invalid(client, errp, 355 "Inconsistent lengths in option %s", 356 nbd_opt_lookup(client->opt)); 357 } 358 client->optlen -= size; 359 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 360 } 361 362 /* nbd_opt_read_name 363 * 364 * Read a string with the format: 365 * uint32_t len (<= NBD_MAX_STRING_SIZE) 366 * len bytes string (not 0-terminated) 367 * 368 * On success, @name will be allocated. 369 * If @length is non-null, it will be set to the actual string length. 370 * 371 * Return -errno on I/O error, 0 if option was completely handled by 372 * sending a reply about inconsistent lengths, or 1 on success. 373 */ 374 static coroutine_fn int 375 nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length, 376 Error **errp) 377 { 378 int ret; 379 uint32_t len; 380 g_autofree char *local_name = NULL; 381 382 *name = NULL; 383 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 384 if (ret <= 0) { 385 return ret; 386 } 387 len = cpu_to_be32(len); 388 389 if (len > NBD_MAX_STRING_SIZE) { 390 return nbd_opt_invalid(client, errp, 391 "Invalid name length: %" PRIu32, len); 392 } 393 394 local_name = g_malloc(len + 1); 395 ret = nbd_opt_read(client, local_name, len, true, errp); 396 if (ret <= 0) { 397 return ret; 398 } 399 local_name[len] = '\0'; 400 401 if (length) { 402 *length = len; 403 } 404 *name = g_steal_pointer(&local_name); 405 406 return 1; 407 } 408 409 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 410 * Return -errno on error, 0 on success. */ 411 static coroutine_fn int 412 nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, Error **errp) 413 { 414 ERRP_GUARD(); 415 size_t name_len, desc_len; 416 uint32_t len; 417 const char *name = exp->name ? exp->name : ""; 418 const char *desc = exp->description ? exp->description : ""; 419 QIOChannel *ioc = client->ioc; 420 int ret; 421 422 trace_nbd_negotiate_send_rep_list(name, desc); 423 name_len = strlen(name); 424 desc_len = strlen(desc); 425 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE); 426 len = name_len + desc_len + sizeof(len); 427 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 428 if (ret < 0) { 429 return ret; 430 } 431 432 len = cpu_to_be32(name_len); 433 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 434 error_prepend(errp, "write failed (name length): "); 435 return -EINVAL; 436 } 437 438 if (nbd_write(ioc, name, name_len, errp) < 0) { 439 error_prepend(errp, "write failed (name buffer): "); 440 return -EINVAL; 441 } 442 443 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 444 error_prepend(errp, "write failed (description buffer): "); 445 return -EINVAL; 446 } 447 448 return 0; 449 } 450 451 /* Process the NBD_OPT_LIST command, with a potential series of replies. 452 * Return -errno on error, 0 on success. */ 453 static coroutine_fn int 454 nbd_negotiate_handle_list(NBDClient *client, Error **errp) 455 { 456 NBDExport *exp; 457 assert(client->opt == NBD_OPT_LIST); 458 459 /* For each export, send a NBD_REP_SERVER reply. */ 460 QTAILQ_FOREACH(exp, &exports, next) { 461 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 462 return -EINVAL; 463 } 464 } 465 /* Finish with a NBD_REP_ACK. */ 466 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 467 } 468 469 static coroutine_fn void 470 nbd_check_meta_export(NBDClient *client, NBDExport *exp) 471 { 472 if (exp != client->contexts.exp) { 473 client->contexts.count = 0; 474 } 475 } 476 477 /* Send a reply to NBD_OPT_EXPORT_NAME. 478 * Return -errno on error, 0 on success. */ 479 static coroutine_fn int 480 nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, 481 Error **errp) 482 { 483 ERRP_GUARD(); 484 g_autofree char *name = NULL; 485 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 486 size_t len; 487 int ret; 488 uint16_t myflags; 489 490 /* Client sends: 491 [20 .. xx] export name (length bytes) 492 Server replies: 493 [ 0 .. 7] size 494 [ 8 .. 9] export flags 495 [10 .. 133] reserved (0) [unless no_zeroes] 496 */ 497 trace_nbd_negotiate_handle_export_name(); 498 if (client->mode >= NBD_MODE_EXTENDED) { 499 error_setg(errp, "Extended headers already negotiated"); 500 return -EINVAL; 501 } 502 if (client->optlen > NBD_MAX_STRING_SIZE) { 503 error_setg(errp, "Bad length received"); 504 return -EINVAL; 505 } 506 name = g_malloc(client->optlen + 1); 507 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 508 return -EIO; 509 } 510 name[client->optlen] = '\0'; 511 client->optlen = 0; 512 513 trace_nbd_negotiate_handle_export_name_request(name); 514 515 client->exp = nbd_export_find(name); 516 if (!client->exp) { 517 error_setg(errp, "export not found"); 518 return -EINVAL; 519 } 520 nbd_check_meta_export(client, client->exp); 521 522 myflags = client->exp->nbdflags; 523 if (client->mode >= NBD_MODE_STRUCTURED) { 524 myflags |= NBD_FLAG_SEND_DF; 525 } 526 if (client->mode >= NBD_MODE_EXTENDED && client->contexts.count) { 527 myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD; 528 } 529 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags); 530 stq_be_p(buf, client->exp->size); 531 stw_be_p(buf + 8, myflags); 532 len = no_zeroes ? 10 : sizeof(buf); 533 ret = nbd_write(client->ioc, buf, len, errp); 534 if (ret < 0) { 535 error_prepend(errp, "write failed: "); 536 return ret; 537 } 538 539 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 540 blk_exp_ref(&client->exp->common); 541 542 return 0; 543 } 544 545 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 546 * The buffer does NOT include the info type prefix. 547 * Return -errno on error, 0 if ready to send more. */ 548 static coroutine_fn int 549 nbd_negotiate_send_info(NBDClient *client, uint16_t info, uint32_t length, 550 void *buf, Error **errp) 551 { 552 int rc; 553 554 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 555 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 556 sizeof(info) + length, errp); 557 if (rc < 0) { 558 return rc; 559 } 560 info = cpu_to_be16(info); 561 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 562 return -EIO; 563 } 564 if (nbd_write(client->ioc, buf, length, errp) < 0) { 565 return -EIO; 566 } 567 return 0; 568 } 569 570 /* nbd_reject_length: Handle any unexpected payload. 571 * @fatal requests that we quit talking to the client, even if we are able 572 * to successfully send an error reply. 573 * Return: 574 * -errno transmission error occurred or @fatal was requested, errp is set 575 * 0 error message successfully sent to client, errp is not set 576 */ 577 static coroutine_fn int 578 nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 579 { 580 int ret; 581 582 assert(client->optlen); 583 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 584 nbd_opt_lookup(client->opt)); 585 if (fatal && !ret) { 586 error_setg(errp, "option '%s' has unexpected length", 587 nbd_opt_lookup(client->opt)); 588 return -EINVAL; 589 } 590 return ret; 591 } 592 593 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 594 * Return -errno on error, 0 if ready for next option, and 1 to move 595 * into transmission phase. */ 596 static coroutine_fn int 597 nbd_negotiate_handle_info(NBDClient *client, Error **errp) 598 { 599 int rc; 600 g_autofree char *name = NULL; 601 NBDExport *exp; 602 uint16_t requests; 603 uint16_t request; 604 uint32_t namelen = 0; 605 bool sendname = false; 606 bool blocksize = false; 607 uint32_t sizes[3]; 608 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 609 uint32_t check_align = 0; 610 uint16_t myflags; 611 612 /* Client sends: 613 4 bytes: L, name length (can be 0) 614 L bytes: export name 615 2 bytes: N, number of requests (can be 0) 616 N * 2 bytes: N requests 617 */ 618 rc = nbd_opt_read_name(client, &name, &namelen, errp); 619 if (rc <= 0) { 620 return rc; 621 } 622 trace_nbd_negotiate_handle_export_name_request(name); 623 624 rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp); 625 if (rc <= 0) { 626 return rc; 627 } 628 requests = be16_to_cpu(requests); 629 trace_nbd_negotiate_handle_info_requests(requests); 630 while (requests--) { 631 rc = nbd_opt_read(client, &request, sizeof(request), false, errp); 632 if (rc <= 0) { 633 return rc; 634 } 635 request = be16_to_cpu(request); 636 trace_nbd_negotiate_handle_info_request(request, 637 nbd_info_lookup(request)); 638 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 639 * everything else is either a request we don't know or 640 * something we send regardless of request */ 641 switch (request) { 642 case NBD_INFO_NAME: 643 sendname = true; 644 break; 645 case NBD_INFO_BLOCK_SIZE: 646 blocksize = true; 647 break; 648 } 649 } 650 if (client->optlen) { 651 return nbd_reject_length(client, false, errp); 652 } 653 654 exp = nbd_export_find(name); 655 if (!exp) { 656 g_autofree char *sane_name = nbd_sanitize_name(name); 657 658 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 659 errp, "export '%s' not present", 660 sane_name); 661 } 662 if (client->opt == NBD_OPT_GO) { 663 nbd_check_meta_export(client, exp); 664 } 665 666 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 667 if (sendname) { 668 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 669 errp); 670 if (rc < 0) { 671 return rc; 672 } 673 } 674 675 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 676 * client request */ 677 if (exp->description) { 678 size_t len = strlen(exp->description); 679 680 assert(len <= NBD_MAX_STRING_SIZE); 681 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 682 len, exp->description, errp); 683 if (rc < 0) { 684 return rc; 685 } 686 } 687 688 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 689 * according to whether the client requested it, and according to 690 * whether this is OPT_INFO or OPT_GO. */ 691 /* minimum - 1 for back-compat, or actual if client will obey it. */ 692 if (client->opt == NBD_OPT_INFO || blocksize) { 693 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk); 694 } else { 695 sizes[0] = 1; 696 } 697 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 698 /* preferred - Hard-code to 4096 for now. 699 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 700 sizes[1] = MAX(4096, sizes[0]); 701 /* maximum - At most 32M, but smaller as appropriate. */ 702 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE); 703 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 704 sizes[0] = cpu_to_be32(sizes[0]); 705 sizes[1] = cpu_to_be32(sizes[1]); 706 sizes[2] = cpu_to_be32(sizes[2]); 707 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 708 sizeof(sizes), sizes, errp); 709 if (rc < 0) { 710 return rc; 711 } 712 713 /* Send NBD_INFO_EXPORT always */ 714 myflags = exp->nbdflags; 715 if (client->mode >= NBD_MODE_STRUCTURED) { 716 myflags |= NBD_FLAG_SEND_DF; 717 } 718 if (client->mode >= NBD_MODE_EXTENDED && 719 (client->contexts.count || client->opt == NBD_OPT_INFO)) { 720 myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD; 721 } 722 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags); 723 stq_be_p(buf, exp->size); 724 stw_be_p(buf + 8, myflags); 725 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 726 sizeof(buf), buf, errp); 727 if (rc < 0) { 728 return rc; 729 } 730 731 /* 732 * If the client is just asking for NBD_OPT_INFO, but forgot to 733 * request block sizes in a situation that would impact 734 * performance, then return an error. But for NBD_OPT_GO, we 735 * tolerate all clients, regardless of alignments. 736 */ 737 if (client->opt == NBD_OPT_INFO && !blocksize && 738 blk_get_request_alignment(exp->common.blk) > 1) { 739 return nbd_negotiate_send_rep_err(client, 740 NBD_REP_ERR_BLOCK_SIZE_REQD, 741 errp, 742 "request NBD_INFO_BLOCK_SIZE to " 743 "use this export"); 744 } 745 746 /* Final reply */ 747 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 748 if (rc < 0) { 749 return rc; 750 } 751 752 if (client->opt == NBD_OPT_GO) { 753 client->exp = exp; 754 client->check_align = check_align; 755 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 756 blk_exp_ref(&client->exp->common); 757 rc = 1; 758 } 759 return rc; 760 } 761 762 /* Callback to learn when QIO TLS upgrade is complete */ 763 struct NBDTLSServerHandshakeData { 764 bool complete; 765 Error *error; 766 Coroutine *co; 767 }; 768 769 static void 770 nbd_server_tls_handshake(QIOTask *task, void *opaque) 771 { 772 struct NBDTLSServerHandshakeData *data = opaque; 773 774 qio_task_propagate_error(task, &data->error); 775 data->complete = true; 776 if (!qemu_coroutine_entered(data->co)) { 777 aio_co_wake(data->co); 778 } 779 } 780 781 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 782 * new channel for all further (now-encrypted) communication. */ 783 static coroutine_fn QIOChannel * 784 nbd_negotiate_handle_starttls(NBDClient *client, Error **errp) 785 { 786 QIOChannel *ioc; 787 QIOChannelTLS *tioc; 788 struct NBDTLSServerHandshakeData data = { 0 }; 789 790 assert(client->opt == NBD_OPT_STARTTLS); 791 792 trace_nbd_negotiate_handle_starttls(); 793 ioc = client->ioc; 794 795 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 796 return NULL; 797 } 798 799 tioc = qio_channel_tls_new_server(ioc, 800 client->tlscreds, 801 client->tlsauthz, 802 errp); 803 if (!tioc) { 804 return NULL; 805 } 806 807 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 808 trace_nbd_negotiate_handle_starttls_handshake(); 809 data.co = qemu_coroutine_self(); 810 qio_channel_tls_handshake(tioc, 811 nbd_server_tls_handshake, 812 &data, 813 NULL, 814 NULL); 815 816 if (!data.complete) { 817 qemu_coroutine_yield(); 818 assert(data.complete); 819 } 820 821 if (data.error) { 822 object_unref(OBJECT(tioc)); 823 error_propagate(errp, data.error); 824 return NULL; 825 } 826 827 return QIO_CHANNEL(tioc); 828 } 829 830 /* nbd_negotiate_send_meta_context 831 * 832 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 833 * 834 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 835 */ 836 static coroutine_fn int 837 nbd_negotiate_send_meta_context(NBDClient *client, const char *context, 838 uint32_t context_id, Error **errp) 839 { 840 NBDOptionReplyMetaContext opt; 841 struct iovec iov[] = { 842 {.iov_base = &opt, .iov_len = sizeof(opt)}, 843 {.iov_base = (void *)context, .iov_len = strlen(context)} 844 }; 845 846 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE); 847 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 848 context_id = 0; 849 } 850 851 trace_nbd_negotiate_meta_query_reply(context, context_id); 852 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 853 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 854 stl_be_p(&opt.context_id, context_id); 855 856 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 857 } 858 859 /* 860 * Return true if @query matches @pattern, or if @query is empty when 861 * the @client is performing _LIST_. 862 */ 863 static coroutine_fn bool 864 nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 865 const char *query) 866 { 867 if (!*query) { 868 trace_nbd_negotiate_meta_query_parse("empty"); 869 return client->opt == NBD_OPT_LIST_META_CONTEXT; 870 } 871 if (strcmp(query, pattern) == 0) { 872 trace_nbd_negotiate_meta_query_parse(pattern); 873 return true; 874 } 875 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 876 return false; 877 } 878 879 /* 880 * Return true and adjust @str in place if it begins with @prefix. 881 */ 882 static coroutine_fn bool 883 nbd_strshift(const char **str, const char *prefix) 884 { 885 size_t len = strlen(prefix); 886 887 if (strncmp(*str, prefix, len) == 0) { 888 *str += len; 889 return true; 890 } 891 return false; 892 } 893 894 /* nbd_meta_base_query 895 * 896 * Handle queries to 'base' namespace. For now, only the base:allocation 897 * context is available. Return true if @query has been handled. 898 */ 899 static coroutine_fn bool 900 nbd_meta_base_query(NBDClient *client, NBDMetaContexts *meta, 901 const char *query) 902 { 903 if (!nbd_strshift(&query, "base:")) { 904 return false; 905 } 906 trace_nbd_negotiate_meta_query_parse("base:"); 907 908 if (nbd_meta_empty_or_pattern(client, "allocation", query)) { 909 meta->base_allocation = true; 910 } 911 return true; 912 } 913 914 /* nbd_meta_qemu_query 915 * 916 * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap: 917 * and qemu:allocation-depth contexts are available. Return true if @query 918 * has been handled. 919 */ 920 static coroutine_fn bool 921 nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *meta, 922 const char *query) 923 { 924 size_t i; 925 926 if (!nbd_strshift(&query, "qemu:")) { 927 return false; 928 } 929 trace_nbd_negotiate_meta_query_parse("qemu:"); 930 931 if (!*query) { 932 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 933 meta->allocation_depth = meta->exp->allocation_depth; 934 if (meta->exp->nr_export_bitmaps) { 935 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 936 } 937 } 938 trace_nbd_negotiate_meta_query_parse("empty"); 939 return true; 940 } 941 942 if (strcmp(query, "allocation-depth") == 0) { 943 trace_nbd_negotiate_meta_query_parse("allocation-depth"); 944 meta->allocation_depth = meta->exp->allocation_depth; 945 return true; 946 } 947 948 if (nbd_strshift(&query, "dirty-bitmap:")) { 949 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 950 if (!*query) { 951 if (client->opt == NBD_OPT_LIST_META_CONTEXT && 952 meta->exp->nr_export_bitmaps) { 953 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 954 } 955 trace_nbd_negotiate_meta_query_parse("empty"); 956 return true; 957 } 958 959 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 960 const char *bm_name; 961 962 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 963 if (strcmp(bm_name, query) == 0) { 964 meta->bitmaps[i] = true; 965 trace_nbd_negotiate_meta_query_parse(query); 966 return true; 967 } 968 } 969 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap match"); 970 return true; 971 } 972 973 trace_nbd_negotiate_meta_query_skip("unknown qemu context"); 974 return true; 975 } 976 977 /* nbd_negotiate_meta_query 978 * 979 * Parse namespace name and call corresponding function to parse body of the 980 * query. 981 * 982 * The only supported namespaces are 'base' and 'qemu'. 983 * 984 * Return -errno on I/O error, 0 if option was completely handled by 985 * sending a reply about inconsistent lengths, or 1 on success. */ 986 static coroutine_fn int 987 nbd_negotiate_meta_query(NBDClient *client, 988 NBDMetaContexts *meta, Error **errp) 989 { 990 int ret; 991 g_autofree char *query = NULL; 992 uint32_t len; 993 994 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 995 if (ret <= 0) { 996 return ret; 997 } 998 len = cpu_to_be32(len); 999 1000 if (len > NBD_MAX_STRING_SIZE) { 1001 trace_nbd_negotiate_meta_query_skip("length too long"); 1002 return nbd_opt_skip(client, len, errp); 1003 } 1004 1005 query = g_malloc(len + 1); 1006 ret = nbd_opt_read(client, query, len, true, errp); 1007 if (ret <= 0) { 1008 return ret; 1009 } 1010 query[len] = '\0'; 1011 1012 if (nbd_meta_base_query(client, meta, query)) { 1013 return 1; 1014 } 1015 if (nbd_meta_qemu_query(client, meta, query)) { 1016 return 1; 1017 } 1018 1019 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 1020 return 1; 1021 } 1022 1023 /* nbd_negotiate_meta_queries 1024 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 1025 * 1026 * Return -errno on I/O error, or 0 if option was completely handled. */ 1027 static coroutine_fn int 1028 nbd_negotiate_meta_queries(NBDClient *client, Error **errp) 1029 { 1030 int ret; 1031 g_autofree char *export_name = NULL; 1032 /* Mark unused to work around https://bugs.llvm.org/show_bug.cgi?id=3888 */ 1033 g_autofree G_GNUC_UNUSED bool *bitmaps = NULL; 1034 NBDMetaContexts local_meta = {0}; 1035 NBDMetaContexts *meta; 1036 uint32_t nb_queries; 1037 size_t i; 1038 size_t count = 0; 1039 1040 if (client->opt == NBD_OPT_SET_META_CONTEXT && 1041 client->mode < NBD_MODE_STRUCTURED) { 1042 return nbd_opt_invalid(client, errp, 1043 "request option '%s' when structured reply " 1044 "is not negotiated", 1045 nbd_opt_lookup(client->opt)); 1046 } 1047 1048 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1049 /* Only change the caller's meta on SET. */ 1050 meta = &local_meta; 1051 } else { 1052 meta = &client->contexts; 1053 } 1054 1055 g_free(meta->bitmaps); 1056 memset(meta, 0, sizeof(*meta)); 1057 1058 ret = nbd_opt_read_name(client, &export_name, NULL, errp); 1059 if (ret <= 0) { 1060 return ret; 1061 } 1062 1063 meta->exp = nbd_export_find(export_name); 1064 if (meta->exp == NULL) { 1065 g_autofree char *sane_name = nbd_sanitize_name(export_name); 1066 1067 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 1068 "export '%s' not present", sane_name); 1069 } 1070 meta->bitmaps = g_new0(bool, meta->exp->nr_export_bitmaps); 1071 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1072 bitmaps = meta->bitmaps; 1073 } 1074 1075 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp); 1076 if (ret <= 0) { 1077 return ret; 1078 } 1079 nb_queries = cpu_to_be32(nb_queries); 1080 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 1081 export_name, nb_queries); 1082 1083 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 1084 /* enable all known contexts */ 1085 meta->base_allocation = true; 1086 meta->allocation_depth = meta->exp->allocation_depth; 1087 if (meta->exp->nr_export_bitmaps) { 1088 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 1089 } 1090 } else { 1091 for (i = 0; i < nb_queries; ++i) { 1092 ret = nbd_negotiate_meta_query(client, meta, errp); 1093 if (ret <= 0) { 1094 return ret; 1095 } 1096 } 1097 } 1098 1099 if (meta->base_allocation) { 1100 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1101 NBD_META_ID_BASE_ALLOCATION, 1102 errp); 1103 if (ret < 0) { 1104 return ret; 1105 } 1106 count++; 1107 } 1108 1109 if (meta->allocation_depth) { 1110 ret = nbd_negotiate_send_meta_context(client, "qemu:allocation-depth", 1111 NBD_META_ID_ALLOCATION_DEPTH, 1112 errp); 1113 if (ret < 0) { 1114 return ret; 1115 } 1116 count++; 1117 } 1118 1119 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 1120 const char *bm_name; 1121 g_autofree char *context = NULL; 1122 1123 if (!meta->bitmaps[i]) { 1124 continue; 1125 } 1126 1127 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 1128 context = g_strdup_printf("qemu:dirty-bitmap:%s", bm_name); 1129 1130 ret = nbd_negotiate_send_meta_context(client, context, 1131 NBD_META_ID_DIRTY_BITMAP + i, 1132 errp); 1133 if (ret < 0) { 1134 return ret; 1135 } 1136 count++; 1137 } 1138 1139 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1140 if (ret == 0) { 1141 meta->count = count; 1142 } 1143 1144 return ret; 1145 } 1146 1147 /* nbd_negotiate_options 1148 * Process all NBD_OPT_* client option commands, during fixed newstyle 1149 * negotiation. 1150 * Return: 1151 * -errno on error, errp is set 1152 * 0 on successful negotiation, errp is not set 1153 * 1 if client sent NBD_OPT_ABORT (i.e. on valid disconnect) or never 1154 * wrote anything (i.e. port probe); errp is not set 1155 */ 1156 static coroutine_fn int 1157 nbd_negotiate_options(NBDClient *client, Error **errp) 1158 { 1159 uint32_t flags; 1160 bool fixedNewstyle = false; 1161 bool no_zeroes = false; 1162 1163 /* Client sends: 1164 [ 0 .. 3] client flags 1165 1166 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1167 [ 0 .. 7] NBD_OPTS_MAGIC 1168 [ 8 .. 11] NBD option 1169 [12 .. 15] Data length 1170 ... Rest of request 1171 1172 [ 0 .. 7] NBD_OPTS_MAGIC 1173 [ 8 .. 11] Second NBD option 1174 [12 .. 15] Data length 1175 ... Rest of request 1176 */ 1177 1178 /* 1179 * Intentionally ignore errors on this first read - we do not want 1180 * to be noisy about a mere port probe, but only for clients that 1181 * start talking the protocol and then quit abruptly. 1182 */ 1183 if (nbd_read32(client->ioc, &flags, "flags", NULL) < 0) { 1184 return 1; 1185 } 1186 client->mode = NBD_MODE_EXPORT_NAME; 1187 trace_nbd_negotiate_options_flags(flags); 1188 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1189 fixedNewstyle = true; 1190 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1191 client->mode = NBD_MODE_SIMPLE; 1192 } 1193 if (flags & NBD_FLAG_C_NO_ZEROES) { 1194 no_zeroes = true; 1195 flags &= ~NBD_FLAG_C_NO_ZEROES; 1196 } 1197 if (flags != 0) { 1198 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1199 return -EINVAL; 1200 } 1201 1202 while (1) { 1203 int ret; 1204 uint32_t option, length; 1205 uint64_t magic; 1206 1207 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1208 return -EINVAL; 1209 } 1210 trace_nbd_negotiate_options_check_magic(magic); 1211 if (magic != NBD_OPTS_MAGIC) { 1212 error_setg(errp, "Bad magic received"); 1213 return -EINVAL; 1214 } 1215 1216 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1217 return -EINVAL; 1218 } 1219 client->opt = option; 1220 1221 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1222 return -EINVAL; 1223 } 1224 assert(!client->optlen); 1225 client->optlen = length; 1226 1227 if (length > NBD_MAX_BUFFER_SIZE) { 1228 error_setg(errp, "len (%" PRIu32 ") is larger than max len (%u)", 1229 length, NBD_MAX_BUFFER_SIZE); 1230 return -EINVAL; 1231 } 1232 1233 trace_nbd_negotiate_options_check_option(option, 1234 nbd_opt_lookup(option)); 1235 if (client->tlscreds && 1236 client->ioc == (QIOChannel *)client->sioc) { 1237 QIOChannel *tioc; 1238 if (!fixedNewstyle) { 1239 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1240 return -EINVAL; 1241 } 1242 switch (option) { 1243 case NBD_OPT_STARTTLS: 1244 if (length) { 1245 /* Unconditionally drop the connection if the client 1246 * can't start a TLS negotiation correctly */ 1247 return nbd_reject_length(client, true, errp); 1248 } 1249 tioc = nbd_negotiate_handle_starttls(client, errp); 1250 if (!tioc) { 1251 return -EIO; 1252 } 1253 ret = 0; 1254 object_unref(OBJECT(client->ioc)); 1255 client->ioc = tioc; 1256 break; 1257 1258 case NBD_OPT_EXPORT_NAME: 1259 /* No way to return an error to client, so drop connection */ 1260 error_setg(errp, "Option 0x%x not permitted before TLS", 1261 option); 1262 return -EINVAL; 1263 1264 default: 1265 /* Let the client keep trying, unless they asked to 1266 * quit. Always try to give an error back to the 1267 * client; but when replying to OPT_ABORT, be aware 1268 * that the client may hang up before receiving the 1269 * error, in which case we are fine ignoring the 1270 * resulting EPIPE. */ 1271 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1272 option == NBD_OPT_ABORT ? NULL : errp, 1273 "Option 0x%" PRIx32 1274 " not permitted before TLS", option); 1275 if (option == NBD_OPT_ABORT) { 1276 return 1; 1277 } 1278 break; 1279 } 1280 } else if (fixedNewstyle) { 1281 switch (option) { 1282 case NBD_OPT_LIST: 1283 if (length) { 1284 ret = nbd_reject_length(client, false, errp); 1285 } else { 1286 ret = nbd_negotiate_handle_list(client, errp); 1287 } 1288 break; 1289 1290 case NBD_OPT_ABORT: 1291 /* NBD spec says we must try to reply before 1292 * disconnecting, but that we must also tolerate 1293 * guests that don't wait for our reply. */ 1294 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1295 return 1; 1296 1297 case NBD_OPT_EXPORT_NAME: 1298 return nbd_negotiate_handle_export_name(client, no_zeroes, 1299 errp); 1300 1301 case NBD_OPT_INFO: 1302 case NBD_OPT_GO: 1303 ret = nbd_negotiate_handle_info(client, errp); 1304 if (ret == 1) { 1305 assert(option == NBD_OPT_GO); 1306 return 0; 1307 } 1308 break; 1309 1310 case NBD_OPT_STARTTLS: 1311 if (length) { 1312 ret = nbd_reject_length(client, false, errp); 1313 } else if (client->tlscreds) { 1314 ret = nbd_negotiate_send_rep_err(client, 1315 NBD_REP_ERR_INVALID, errp, 1316 "TLS already enabled"); 1317 } else { 1318 ret = nbd_negotiate_send_rep_err(client, 1319 NBD_REP_ERR_POLICY, errp, 1320 "TLS not configured"); 1321 } 1322 break; 1323 1324 case NBD_OPT_STRUCTURED_REPLY: 1325 if (length) { 1326 ret = nbd_reject_length(client, false, errp); 1327 } else if (client->mode >= NBD_MODE_EXTENDED) { 1328 ret = nbd_negotiate_send_rep_err( 1329 client, NBD_REP_ERR_EXT_HEADER_REQD, errp, 1330 "extended headers already negotiated"); 1331 } else if (client->mode >= NBD_MODE_STRUCTURED) { 1332 ret = nbd_negotiate_send_rep_err( 1333 client, NBD_REP_ERR_INVALID, errp, 1334 "structured reply already negotiated"); 1335 } else { 1336 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1337 client->mode = NBD_MODE_STRUCTURED; 1338 } 1339 break; 1340 1341 case NBD_OPT_LIST_META_CONTEXT: 1342 case NBD_OPT_SET_META_CONTEXT: 1343 ret = nbd_negotiate_meta_queries(client, errp); 1344 break; 1345 1346 case NBD_OPT_EXTENDED_HEADERS: 1347 if (length) { 1348 ret = nbd_reject_length(client, false, errp); 1349 } else if (client->mode >= NBD_MODE_EXTENDED) { 1350 ret = nbd_negotiate_send_rep_err( 1351 client, NBD_REP_ERR_INVALID, errp, 1352 "extended headers already negotiated"); 1353 } else { 1354 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1355 client->mode = NBD_MODE_EXTENDED; 1356 } 1357 break; 1358 1359 default: 1360 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1361 "Unsupported option %" PRIu32 " (%s)", 1362 option, nbd_opt_lookup(option)); 1363 break; 1364 } 1365 } else { 1366 /* 1367 * If broken new-style we should drop the connection 1368 * for anything except NBD_OPT_EXPORT_NAME 1369 */ 1370 switch (option) { 1371 case NBD_OPT_EXPORT_NAME: 1372 return nbd_negotiate_handle_export_name(client, no_zeroes, 1373 errp); 1374 1375 default: 1376 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1377 option, nbd_opt_lookup(option)); 1378 return -EINVAL; 1379 } 1380 } 1381 if (ret < 0) { 1382 return ret; 1383 } 1384 } 1385 } 1386 1387 /* nbd_negotiate 1388 * Return: 1389 * -errno on error, errp is set 1390 * 0 on successful negotiation, errp is not set 1391 * 1 if client sent NBD_OPT_ABORT (i.e. on valid disconnect) or never 1392 * wrote anything (i.e. port probe); errp is not set 1393 */ 1394 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1395 { 1396 ERRP_GUARD(); 1397 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1398 int ret; 1399 1400 /* Old style negotiation header, no room for options 1401 [ 0 .. 7] passwd ("NBDMAGIC") 1402 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1403 [16 .. 23] size 1404 [24 .. 27] export flags (zero-extended) 1405 [28 .. 151] reserved (0) 1406 1407 New style negotiation header, client can send options 1408 [ 0 .. 7] passwd ("NBDMAGIC") 1409 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1410 [16 .. 17] server flags (0) 1411 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1412 */ 1413 1414 if (!qio_channel_set_blocking(client->ioc, false, errp)) { 1415 return -EINVAL; 1416 } 1417 qio_channel_set_follow_coroutine_ctx(client->ioc, true); 1418 1419 trace_nbd_negotiate_begin(); 1420 memcpy(buf, "NBDMAGIC", 8); 1421 1422 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1423 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1424 1425 /* 1426 * Be silent about failure to write our greeting: there is nothing 1427 * wrong with a client testing if our port is alive. 1428 */ 1429 if (nbd_write(client->ioc, buf, 18, NULL) < 0) { 1430 return 1; 1431 } 1432 ret = nbd_negotiate_options(client, errp); 1433 if (ret != 0) { 1434 if (ret < 0) { 1435 error_prepend(errp, "option negotiation failed: "); 1436 } 1437 return ret; 1438 } 1439 1440 assert(!client->optlen); 1441 trace_nbd_negotiate_success(); 1442 1443 return 0; 1444 } 1445 1446 /* nbd_read_eof 1447 * Tries to read @size bytes from @ioc. This is a local implementation of 1448 * qio_channel_readv_all_eof. We have it here because we need it to be 1449 * interruptible and to know when the coroutine is yielding. 1450 * Returns 1 on success 1451 * 0 on eof, when no data was read (errp is not set) 1452 * negative errno on failure (errp is set) 1453 */ 1454 static inline int coroutine_fn 1455 nbd_read_eof(NBDClient *client, void *buffer, size_t size, Error **errp) 1456 { 1457 bool partial = false; 1458 1459 assert(size); 1460 while (size > 0) { 1461 struct iovec iov = { .iov_base = buffer, .iov_len = size }; 1462 ssize_t len; 1463 1464 len = qio_channel_readv(client->ioc, &iov, 1, errp); 1465 if (len == QIO_CHANNEL_ERR_BLOCK) { 1466 WITH_QEMU_LOCK_GUARD(&client->lock) { 1467 client->read_yielding = true; 1468 1469 /* Prompt main loop thread to re-run nbd_drained_poll() */ 1470 aio_wait_kick(); 1471 } 1472 qio_channel_yield(client->ioc, G_IO_IN); 1473 WITH_QEMU_LOCK_GUARD(&client->lock) { 1474 client->read_yielding = false; 1475 if (client->quiescing) { 1476 return -EAGAIN; 1477 } 1478 } 1479 continue; 1480 } else if (len < 0) { 1481 return -EIO; 1482 } else if (len == 0) { 1483 if (partial) { 1484 error_setg(errp, 1485 "Unexpected end-of-file before all bytes were read"); 1486 return -EIO; 1487 } else { 1488 return 0; 1489 } 1490 } 1491 1492 partial = true; 1493 size -= len; 1494 buffer = (uint8_t *) buffer + len; 1495 } 1496 return 1; 1497 } 1498 1499 static int coroutine_fn nbd_receive_request(NBDClient *client, NBDRequest *request, 1500 Error **errp) 1501 { 1502 uint8_t buf[NBD_EXTENDED_REQUEST_SIZE]; 1503 uint32_t magic, expect; 1504 int ret; 1505 size_t size = client->mode >= NBD_MODE_EXTENDED ? 1506 NBD_EXTENDED_REQUEST_SIZE : NBD_REQUEST_SIZE; 1507 1508 ret = nbd_read_eof(client, buf, size, errp); 1509 if (ret < 0) { 1510 return ret; 1511 } 1512 if (ret == 0) { 1513 return -EIO; 1514 } 1515 1516 /* 1517 * Compact request 1518 * [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1519 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1520 * [ 6 .. 7] type (NBD_CMD_READ, ...) 1521 * [ 8 .. 15] cookie 1522 * [16 .. 23] from 1523 * [24 .. 27] len 1524 * Extended request 1525 * [ 0 .. 3] magic (NBD_EXTENDED_REQUEST_MAGIC) 1526 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, NBD_CMD_FLAG_PAYLOAD_LEN, ...) 1527 * [ 6 .. 7] type (NBD_CMD_READ, ...) 1528 * [ 8 .. 15] cookie 1529 * [16 .. 23] from 1530 * [24 .. 31] len 1531 */ 1532 1533 magic = ldl_be_p(buf); 1534 request->flags = lduw_be_p(buf + 4); 1535 request->type = lduw_be_p(buf + 6); 1536 request->cookie = ldq_be_p(buf + 8); 1537 request->from = ldq_be_p(buf + 16); 1538 if (client->mode >= NBD_MODE_EXTENDED) { 1539 request->len = ldq_be_p(buf + 24); 1540 expect = NBD_EXTENDED_REQUEST_MAGIC; 1541 } else { 1542 request->len = (uint32_t)ldl_be_p(buf + 24); /* widen 32 to 64 bits */ 1543 expect = NBD_REQUEST_MAGIC; 1544 } 1545 1546 trace_nbd_receive_request(magic, request->flags, request->type, 1547 request->from, request->len); 1548 1549 if (magic != expect) { 1550 error_setg(errp, "invalid magic (got 0x%" PRIx32 ", expected 0x%" 1551 PRIx32 ")", magic, expect); 1552 return -EINVAL; 1553 } 1554 return 0; 1555 } 1556 1557 #define MAX_NBD_REQUESTS 16 1558 1559 /* Runs in export AioContext and main loop thread */ 1560 void nbd_client_get(NBDClient *client) 1561 { 1562 qatomic_inc(&client->refcount); 1563 } 1564 1565 void nbd_client_put(NBDClient *client) 1566 { 1567 assert(qemu_in_main_thread()); 1568 1569 if (qatomic_fetch_dec(&client->refcount) == 1) { 1570 /* The last reference should be dropped by client->close, 1571 * which is called by client_close. 1572 */ 1573 assert(client->closing); 1574 1575 object_unref(OBJECT(client->sioc)); 1576 object_unref(OBJECT(client->ioc)); 1577 if (client->tlscreds) { 1578 object_unref(OBJECT(client->tlscreds)); 1579 } 1580 g_free(client->tlsauthz); 1581 if (client->exp) { 1582 QTAILQ_REMOVE(&client->exp->clients, client, next); 1583 blk_exp_unref(&client->exp->common); 1584 } 1585 g_free(client->contexts.bitmaps); 1586 qemu_mutex_destroy(&client->lock); 1587 g_free(client); 1588 } 1589 } 1590 1591 /* 1592 * Tries to release the reference to @client, but only if other references 1593 * remain. This is an optimization for the common case where we want to avoid 1594 * the expense of scheduling nbd_client_put() in the main loop thread. 1595 * 1596 * Returns true upon success or false if the reference was not released because 1597 * it is the last reference. 1598 */ 1599 static bool nbd_client_put_nonzero(NBDClient *client) 1600 { 1601 int old = qatomic_read(&client->refcount); 1602 int expected; 1603 1604 do { 1605 if (old == 1) { 1606 return false; 1607 } 1608 1609 expected = old; 1610 old = qatomic_cmpxchg(&client->refcount, expected, expected - 1); 1611 } while (old != expected); 1612 1613 return true; 1614 } 1615 1616 static void client_close(NBDClient *client, bool negotiated) 1617 { 1618 assert(qemu_in_main_thread()); 1619 1620 WITH_QEMU_LOCK_GUARD(&client->lock) { 1621 if (client->closing) { 1622 return; 1623 } 1624 1625 client->closing = true; 1626 } 1627 1628 /* Force requests to finish. They will drop their own references, 1629 * then we'll close the socket and free the NBDClient. 1630 */ 1631 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1632 NULL); 1633 1634 /* Also tell the client, so that they release their reference. */ 1635 if (client->close_fn) { 1636 client->close_fn(client, negotiated); 1637 } 1638 } 1639 1640 /* Runs in export AioContext with client->lock held */ 1641 static NBDRequestData *nbd_request_get(NBDClient *client) 1642 { 1643 NBDRequestData *req; 1644 1645 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1646 client->nb_requests++; 1647 1648 req = g_new0(NBDRequestData, 1); 1649 req->client = client; 1650 return req; 1651 } 1652 1653 /* Runs in export AioContext with client->lock held */ 1654 static void nbd_request_put(NBDRequestData *req) 1655 { 1656 NBDClient *client = req->client; 1657 1658 if (req->data) { 1659 qemu_vfree(req->data); 1660 } 1661 g_free(req); 1662 1663 client->nb_requests--; 1664 1665 if (client->quiescing && client->nb_requests == 0) { 1666 aio_wait_kick(); 1667 } 1668 1669 nbd_client_receive_next_request(client); 1670 } 1671 1672 static void blk_aio_attached(AioContext *ctx, void *opaque) 1673 { 1674 NBDExport *exp = opaque; 1675 NBDClient *client; 1676 1677 assert(qemu_in_main_thread()); 1678 1679 trace_nbd_blk_aio_attached(exp->name, ctx); 1680 1681 exp->common.ctx = ctx; 1682 1683 QTAILQ_FOREACH(client, &exp->clients, next) { 1684 WITH_QEMU_LOCK_GUARD(&client->lock) { 1685 assert(client->nb_requests == 0); 1686 assert(client->recv_coroutine == NULL); 1687 assert(client->send_coroutine == NULL); 1688 } 1689 } 1690 } 1691 1692 static void blk_aio_detach(void *opaque) 1693 { 1694 NBDExport *exp = opaque; 1695 1696 assert(qemu_in_main_thread()); 1697 1698 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx); 1699 1700 exp->common.ctx = NULL; 1701 } 1702 1703 static void nbd_drained_begin(void *opaque) 1704 { 1705 NBDExport *exp = opaque; 1706 NBDClient *client; 1707 1708 assert(qemu_in_main_thread()); 1709 1710 QTAILQ_FOREACH(client, &exp->clients, next) { 1711 WITH_QEMU_LOCK_GUARD(&client->lock) { 1712 client->quiescing = true; 1713 } 1714 } 1715 } 1716 1717 static void nbd_drained_end(void *opaque) 1718 { 1719 NBDExport *exp = opaque; 1720 NBDClient *client; 1721 1722 assert(qemu_in_main_thread()); 1723 1724 QTAILQ_FOREACH(client, &exp->clients, next) { 1725 WITH_QEMU_LOCK_GUARD(&client->lock) { 1726 client->quiescing = false; 1727 nbd_client_receive_next_request(client); 1728 } 1729 } 1730 } 1731 1732 /* Runs in export AioContext */ 1733 static void nbd_wake_read_bh(void *opaque) 1734 { 1735 NBDClient *client = opaque; 1736 qio_channel_wake_read(client->ioc); 1737 } 1738 1739 static bool nbd_drained_poll(void *opaque) 1740 { 1741 NBDExport *exp = opaque; 1742 NBDClient *client; 1743 1744 assert(qemu_in_main_thread()); 1745 1746 QTAILQ_FOREACH(client, &exp->clients, next) { 1747 WITH_QEMU_LOCK_GUARD(&client->lock) { 1748 if (client->nb_requests != 0) { 1749 /* 1750 * If there's a coroutine waiting for a request on nbd_read_eof() 1751 * enter it here so we don't depend on the client to wake it up. 1752 * 1753 * Schedule a BH in the export AioContext to avoid missing the 1754 * wake up due to the race between qio_channel_wake_read() and 1755 * qio_channel_yield(). 1756 */ 1757 if (client->recv_coroutine != NULL && client->read_yielding) { 1758 aio_bh_schedule_oneshot(nbd_export_aio_context(client->exp), 1759 nbd_wake_read_bh, client); 1760 } 1761 1762 return true; 1763 } 1764 } 1765 } 1766 1767 return false; 1768 } 1769 1770 static void nbd_eject_notifier(Notifier *n, void *data) 1771 { 1772 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1773 1774 assert(qemu_in_main_thread()); 1775 1776 blk_exp_request_shutdown(&exp->common); 1777 } 1778 1779 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) 1780 { 1781 NBDExport *nbd_exp = container_of(exp, NBDExport, common); 1782 assert(exp->drv == &blk_exp_nbd); 1783 assert(nbd_exp->eject_notifier_blk == NULL); 1784 1785 blk_ref(blk); 1786 nbd_exp->eject_notifier_blk = blk; 1787 nbd_exp->eject_notifier.notify = nbd_eject_notifier; 1788 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier); 1789 } 1790 1791 static const BlockDevOps nbd_block_ops = { 1792 .drained_begin = nbd_drained_begin, 1793 .drained_end = nbd_drained_end, 1794 .drained_poll = nbd_drained_poll, 1795 }; 1796 1797 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, 1798 Error **errp) 1799 { 1800 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1801 BlockExportOptionsNbd *arg = &exp_args->u.nbd; 1802 const char *name = arg->name ?: exp_args->node_name; 1803 BlockBackend *blk = blk_exp->blk; 1804 int64_t size; 1805 uint64_t perm, shared_perm; 1806 bool readonly = !exp_args->writable; 1807 BlockDirtyBitmapOrStrList *bitmaps; 1808 size_t i; 1809 int ret; 1810 1811 GLOBAL_STATE_CODE(); 1812 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); 1813 1814 if (!nbd_server_is_running()) { 1815 error_setg(errp, "NBD server not running"); 1816 return -EINVAL; 1817 } 1818 1819 if (strlen(name) > NBD_MAX_STRING_SIZE) { 1820 error_setg(errp, "export name '%s' too long", name); 1821 return -EINVAL; 1822 } 1823 1824 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) { 1825 error_setg(errp, "description '%s' too long", arg->description); 1826 return -EINVAL; 1827 } 1828 1829 if (nbd_export_find(name)) { 1830 error_setg(errp, "NBD server already has export named '%s'", name); 1831 return -EEXIST; 1832 } 1833 1834 size = blk_getlength(blk); 1835 if (size < 0) { 1836 error_setg_errno(errp, -size, 1837 "Failed to determine the NBD export's length"); 1838 return size; 1839 } 1840 1841 /* Don't allow resize while the NBD server is running, otherwise we don't 1842 * care what happens with the node. */ 1843 blk_get_perm(blk, &perm, &shared_perm); 1844 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); 1845 if (ret < 0) { 1846 return ret; 1847 } 1848 1849 QTAILQ_INIT(&exp->clients); 1850 exp->name = g_strdup(name); 1851 exp->description = g_strdup(arg->description); 1852 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1853 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1854 1855 if (nbd_server_max_connections() != 1) { 1856 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1857 } 1858 if (readonly) { 1859 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1860 } else { 1861 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1862 NBD_FLAG_SEND_FAST_ZERO); 1863 } 1864 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1865 1866 bdrv_graph_rdlock_main_loop(); 1867 1868 for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) { 1869 exp->nr_export_bitmaps++; 1870 } 1871 exp->export_bitmaps = g_new0(BdrvDirtyBitmap *, exp->nr_export_bitmaps); 1872 for (i = 0, bitmaps = arg->bitmaps; bitmaps; 1873 i++, bitmaps = bitmaps->next) 1874 { 1875 const char *bitmap; 1876 BlockDriverState *bs = blk_bs(blk); 1877 BdrvDirtyBitmap *bm = NULL; 1878 1879 switch (bitmaps->value->type) { 1880 case QTYPE_QSTRING: 1881 bitmap = bitmaps->value->u.local; 1882 while (bs) { 1883 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1884 if (bm != NULL) { 1885 break; 1886 } 1887 1888 bs = bdrv_filter_or_cow_bs(bs); 1889 } 1890 1891 if (bm == NULL) { 1892 ret = -ENOENT; 1893 error_setg(errp, "Bitmap '%s' is not found", 1894 bitmaps->value->u.local); 1895 goto fail; 1896 } 1897 1898 if (readonly && bdrv_is_writable(bs) && 1899 bdrv_dirty_bitmap_enabled(bm)) { 1900 ret = -EINVAL; 1901 error_setg(errp, "Enabled bitmap '%s' incompatible with " 1902 "readonly export", bitmap); 1903 goto fail; 1904 } 1905 break; 1906 case QTYPE_QDICT: 1907 bitmap = bitmaps->value->u.external.name; 1908 bm = block_dirty_bitmap_lookup(bitmaps->value->u.external.node, 1909 bitmap, NULL, errp); 1910 if (!bm) { 1911 ret = -ENOENT; 1912 goto fail; 1913 } 1914 break; 1915 default: 1916 abort(); 1917 } 1918 1919 assert(bm); 1920 1921 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1922 ret = -EINVAL; 1923 goto fail; 1924 } 1925 1926 exp->export_bitmaps[i] = bm; 1927 assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE); 1928 } 1929 1930 /* Mark bitmaps busy in a separate loop, to simplify roll-back concerns. */ 1931 for (i = 0; i < exp->nr_export_bitmaps; i++) { 1932 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true); 1933 } 1934 1935 exp->allocation_depth = arg->allocation_depth; 1936 1937 /* 1938 * We need to inhibit request queuing in the block layer to ensure we can 1939 * be properly quiesced when entering a drained section, as our coroutines 1940 * servicing pending requests might enter blk_pread(). 1941 */ 1942 blk_set_disable_request_queuing(blk, true); 1943 1944 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1945 1946 blk_set_dev_ops(blk, &nbd_block_ops, exp); 1947 1948 QTAILQ_INSERT_TAIL(&exports, exp, next); 1949 1950 bdrv_graph_rdunlock_main_loop(); 1951 1952 return 0; 1953 1954 fail: 1955 bdrv_graph_rdunlock_main_loop(); 1956 g_free(exp->export_bitmaps); 1957 g_free(exp->name); 1958 g_free(exp->description); 1959 return ret; 1960 } 1961 1962 NBDExport *nbd_export_find(const char *name) 1963 { 1964 NBDExport *exp; 1965 QTAILQ_FOREACH(exp, &exports, next) { 1966 if (strcmp(name, exp->name) == 0) { 1967 return exp; 1968 } 1969 } 1970 1971 return NULL; 1972 } 1973 1974 AioContext * 1975 nbd_export_aio_context(NBDExport *exp) 1976 { 1977 return exp->common.ctx; 1978 } 1979 1980 static void nbd_export_request_shutdown(BlockExport *blk_exp) 1981 { 1982 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1983 NBDClient *client, *next; 1984 1985 blk_exp_ref(&exp->common); 1986 /* 1987 * TODO: Should we expand QMP BlockExportRemoveMode enum to allow a 1988 * close mode that stops advertising the export to new clients but 1989 * still permits existing clients to run to completion? Because of 1990 * that possibility, nbd_export_close() can be called more than 1991 * once on an export. 1992 */ 1993 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1994 client_close(client, true); 1995 } 1996 if (exp->name) { 1997 g_free(exp->name); 1998 exp->name = NULL; 1999 QTAILQ_REMOVE(&exports, exp, next); 2000 } 2001 blk_exp_unref(&exp->common); 2002 } 2003 2004 static void nbd_export_delete(BlockExport *blk_exp) 2005 { 2006 size_t i; 2007 NBDExport *exp = container_of(blk_exp, NBDExport, common); 2008 2009 assert(exp->name == NULL); 2010 assert(QTAILQ_EMPTY(&exp->clients)); 2011 2012 g_free(exp->description); 2013 exp->description = NULL; 2014 2015 if (exp->eject_notifier_blk) { 2016 notifier_remove(&exp->eject_notifier); 2017 blk_unref(exp->eject_notifier_blk); 2018 } 2019 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached, 2020 blk_aio_detach, exp); 2021 blk_set_disable_request_queuing(exp->common.blk, false); 2022 2023 for (i = 0; i < exp->nr_export_bitmaps; i++) { 2024 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], false); 2025 } 2026 } 2027 2028 const BlockExportDriver blk_exp_nbd = { 2029 .type = BLOCK_EXPORT_TYPE_NBD, 2030 .instance_size = sizeof(NBDExport), 2031 .supports_inactive = true, 2032 .create = nbd_export_create, 2033 .delete = nbd_export_delete, 2034 .request_shutdown = nbd_export_request_shutdown, 2035 }; 2036 2037 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 2038 unsigned niov, Error **errp) 2039 { 2040 int ret; 2041 2042 g_assert(qemu_in_coroutine()); 2043 qemu_co_mutex_lock(&client->send_lock); 2044 client->send_coroutine = qemu_coroutine_self(); 2045 2046 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 2047 2048 client->send_coroutine = NULL; 2049 qemu_co_mutex_unlock(&client->send_lock); 2050 2051 return ret; 2052 } 2053 2054 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 2055 uint64_t cookie) 2056 { 2057 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 2058 stl_be_p(&reply->error, error); 2059 stq_be_p(&reply->cookie, cookie); 2060 } 2061 2062 static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client, 2063 NBDRequest *request, 2064 uint32_t error, 2065 void *data, 2066 uint64_t len, 2067 Error **errp) 2068 { 2069 NBDSimpleReply reply; 2070 int nbd_err = system_errno_to_nbd_errno(error); 2071 struct iovec iov[] = { 2072 {.iov_base = &reply, .iov_len = sizeof(reply)}, 2073 {.iov_base = data, .iov_len = len} 2074 }; 2075 2076 assert(!len || !nbd_err); 2077 assert(len <= NBD_MAX_BUFFER_SIZE); 2078 assert(client->mode < NBD_MODE_STRUCTURED || 2079 (client->mode == NBD_MODE_STRUCTURED && 2080 request->type != NBD_CMD_READ)); 2081 trace_nbd_co_send_simple_reply(request->cookie, nbd_err, 2082 nbd_err_lookup(nbd_err), len); 2083 set_be_simple_reply(&reply, nbd_err, request->cookie); 2084 2085 return nbd_co_send_iov(client, iov, 2, errp); 2086 } 2087 2088 /* 2089 * Prepare the header of a reply chunk for network transmission. 2090 * 2091 * On input, @iov is partially initialized: iov[0].iov_base must point 2092 * to an uninitialized NBDReply, while the remaining @niov elements 2093 * (if any) must be ready for transmission. This function then 2094 * populates iov[0] for transmission. 2095 */ 2096 static inline void set_be_chunk(NBDClient *client, struct iovec *iov, 2097 size_t niov, uint16_t flags, uint16_t type, 2098 NBDRequest *request) 2099 { 2100 size_t i, length = 0; 2101 2102 for (i = 1; i < niov; i++) { 2103 length += iov[i].iov_len; 2104 } 2105 assert(length <= NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData)); 2106 2107 if (client->mode >= NBD_MODE_EXTENDED) { 2108 NBDExtendedReplyChunk *chunk = iov->iov_base; 2109 2110 iov[0].iov_len = sizeof(*chunk); 2111 stl_be_p(&chunk->magic, NBD_EXTENDED_REPLY_MAGIC); 2112 stw_be_p(&chunk->flags, flags); 2113 stw_be_p(&chunk->type, type); 2114 stq_be_p(&chunk->cookie, request->cookie); 2115 stq_be_p(&chunk->offset, request->from); 2116 stq_be_p(&chunk->length, length); 2117 } else { 2118 NBDStructuredReplyChunk *chunk = iov->iov_base; 2119 2120 iov[0].iov_len = sizeof(*chunk); 2121 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 2122 stw_be_p(&chunk->flags, flags); 2123 stw_be_p(&chunk->type, type); 2124 stq_be_p(&chunk->cookie, request->cookie); 2125 stl_be_p(&chunk->length, length); 2126 } 2127 } 2128 2129 static int coroutine_fn nbd_co_send_chunk_done(NBDClient *client, 2130 NBDRequest *request, 2131 Error **errp) 2132 { 2133 NBDReply hdr; 2134 struct iovec iov[] = { 2135 {.iov_base = &hdr}, 2136 }; 2137 2138 trace_nbd_co_send_chunk_done(request->cookie); 2139 set_be_chunk(client, iov, 1, NBD_REPLY_FLAG_DONE, 2140 NBD_REPLY_TYPE_NONE, request); 2141 return nbd_co_send_iov(client, iov, 1, errp); 2142 } 2143 2144 static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client, 2145 NBDRequest *request, 2146 uint64_t offset, 2147 void *data, 2148 uint64_t size, 2149 bool final, 2150 Error **errp) 2151 { 2152 NBDReply hdr; 2153 NBDStructuredReadData chunk; 2154 struct iovec iov[] = { 2155 {.iov_base = &hdr}, 2156 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2157 {.iov_base = data, .iov_len = size} 2158 }; 2159 2160 assert(size && size <= NBD_MAX_BUFFER_SIZE); 2161 trace_nbd_co_send_chunk_read(request->cookie, offset, data, size); 2162 set_be_chunk(client, iov, 3, final ? NBD_REPLY_FLAG_DONE : 0, 2163 NBD_REPLY_TYPE_OFFSET_DATA, request); 2164 stq_be_p(&chunk.offset, offset); 2165 2166 return nbd_co_send_iov(client, iov, 3, errp); 2167 } 2168 2169 static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client, 2170 NBDRequest *request, 2171 uint32_t error, 2172 const char *msg, 2173 Error **errp) 2174 { 2175 NBDReply hdr; 2176 NBDStructuredError chunk; 2177 int nbd_err = system_errno_to_nbd_errno(error); 2178 struct iovec iov[] = { 2179 {.iov_base = &hdr}, 2180 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2181 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 2182 }; 2183 2184 assert(nbd_err); 2185 trace_nbd_co_send_chunk_error(request->cookie, nbd_err, 2186 nbd_err_lookup(nbd_err), msg ? msg : ""); 2187 set_be_chunk(client, iov, 3, NBD_REPLY_FLAG_DONE, 2188 NBD_REPLY_TYPE_ERROR, request); 2189 stl_be_p(&chunk.error, nbd_err); 2190 stw_be_p(&chunk.message_length, iov[2].iov_len); 2191 2192 return nbd_co_send_iov(client, iov, 3, errp); 2193 } 2194 2195 /* Do a sparse read and send the structured reply to the client. 2196 * Returns -errno if sending fails. blk_co_block_status_above() failure is 2197 * reported to the client, at which point this function succeeds. 2198 */ 2199 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 2200 NBDRequest *request, 2201 uint64_t offset, 2202 uint8_t *data, 2203 uint64_t size, 2204 Error **errp) 2205 { 2206 int ret = 0; 2207 NBDExport *exp = client->exp; 2208 size_t progress = 0; 2209 2210 assert(size <= NBD_MAX_BUFFER_SIZE); 2211 while (progress < size) { 2212 int64_t pnum; 2213 int status = blk_co_block_status_above(exp->common.blk, NULL, 2214 offset + progress, 2215 size - progress, &pnum, NULL, 2216 NULL); 2217 bool final; 2218 2219 if (status < 0) { 2220 char *msg = g_strdup_printf("unable to check for holes: %s", 2221 strerror(-status)); 2222 2223 ret = nbd_co_send_chunk_error(client, request, -status, msg, errp); 2224 g_free(msg); 2225 return ret; 2226 } 2227 assert(pnum && pnum <= size - progress); 2228 final = progress + pnum == size; 2229 if (status & BDRV_BLOCK_ZERO) { 2230 NBDReply hdr; 2231 NBDStructuredReadHole chunk; 2232 struct iovec iov[] = { 2233 {.iov_base = &hdr}, 2234 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2235 }; 2236 2237 trace_nbd_co_send_chunk_read_hole(request->cookie, 2238 offset + progress, pnum); 2239 set_be_chunk(client, iov, 2, 2240 final ? NBD_REPLY_FLAG_DONE : 0, 2241 NBD_REPLY_TYPE_OFFSET_HOLE, request); 2242 stq_be_p(&chunk.offset, offset + progress); 2243 stl_be_p(&chunk.length, pnum); 2244 ret = nbd_co_send_iov(client, iov, 2, errp); 2245 } else { 2246 ret = blk_co_pread(exp->common.blk, offset + progress, pnum, 2247 data + progress, 0); 2248 if (ret < 0) { 2249 error_setg_errno(errp, -ret, "reading from file failed"); 2250 break; 2251 } 2252 ret = nbd_co_send_chunk_read(client, request, offset + progress, 2253 data + progress, pnum, final, errp); 2254 } 2255 2256 if (ret < 0) { 2257 break; 2258 } 2259 progress += pnum; 2260 } 2261 return ret; 2262 } 2263 2264 typedef struct NBDExtentArray { 2265 NBDExtent64 *extents; 2266 unsigned int nb_alloc; 2267 unsigned int count; 2268 uint64_t total_length; 2269 bool extended; 2270 bool can_add; 2271 bool converted_to_be; 2272 } NBDExtentArray; 2273 2274 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc, 2275 NBDMode mode) 2276 { 2277 NBDExtentArray *ea = g_new0(NBDExtentArray, 1); 2278 2279 assert(mode >= NBD_MODE_STRUCTURED); 2280 ea->nb_alloc = nb_alloc; 2281 ea->extents = g_new(NBDExtent64, nb_alloc); 2282 ea->extended = mode >= NBD_MODE_EXTENDED; 2283 ea->can_add = true; 2284 2285 return ea; 2286 } 2287 2288 static void nbd_extent_array_free(NBDExtentArray *ea) 2289 { 2290 g_free(ea->extents); 2291 g_free(ea); 2292 } 2293 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free) 2294 2295 /* Further modifications of the array after conversion are abandoned */ 2296 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea) 2297 { 2298 int i; 2299 2300 assert(!ea->converted_to_be); 2301 assert(ea->extended); 2302 ea->can_add = false; 2303 ea->converted_to_be = true; 2304 2305 for (i = 0; i < ea->count; i++) { 2306 ea->extents[i].length = cpu_to_be64(ea->extents[i].length); 2307 ea->extents[i].flags = cpu_to_be64(ea->extents[i].flags); 2308 } 2309 } 2310 2311 /* Further modifications of the array after conversion are abandoned */ 2312 static NBDExtent32 *nbd_extent_array_convert_to_narrow(NBDExtentArray *ea) 2313 { 2314 int i; 2315 NBDExtent32 *extents = g_new(NBDExtent32, ea->count); 2316 2317 assert(!ea->converted_to_be); 2318 assert(!ea->extended); 2319 ea->can_add = false; 2320 ea->converted_to_be = true; 2321 2322 for (i = 0; i < ea->count; i++) { 2323 assert((ea->extents[i].length | ea->extents[i].flags) <= UINT32_MAX); 2324 extents[i].length = cpu_to_be32(ea->extents[i].length); 2325 extents[i].flags = cpu_to_be32(ea->extents[i].flags); 2326 } 2327 2328 return extents; 2329 } 2330 2331 /* 2332 * Add extent to NBDExtentArray. If extent can't be added (no available space), 2333 * return -1. 2334 * For safety, when returning -1 for the first time, .can_add is set to false, 2335 * and further calls to nbd_extent_array_add() will crash. 2336 * (this avoids the situation where a caller ignores failure to add one extent, 2337 * where adding another extent that would squash into the last array entry 2338 * would result in an incorrect range reported to the client) 2339 */ 2340 static int nbd_extent_array_add(NBDExtentArray *ea, 2341 uint64_t length, uint32_t flags) 2342 { 2343 assert(ea->can_add); 2344 2345 if (!length) { 2346 return 0; 2347 } 2348 if (!ea->extended) { 2349 assert(length <= UINT32_MAX); 2350 } 2351 2352 /* Extend previous extent if flags are the same */ 2353 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) { 2354 uint64_t sum = length + ea->extents[ea->count - 1].length; 2355 2356 /* 2357 * sum cannot overflow: the block layer bounds image size at 2358 * 2^63, and ea->extents[].length comes from the block layer. 2359 */ 2360 assert(sum >= length); 2361 if (sum <= UINT32_MAX || ea->extended) { 2362 ea->extents[ea->count - 1].length = sum; 2363 ea->total_length += length; 2364 return 0; 2365 } 2366 } 2367 2368 if (ea->count >= ea->nb_alloc) { 2369 ea->can_add = false; 2370 return -1; 2371 } 2372 2373 ea->total_length += length; 2374 ea->extents[ea->count] = (NBDExtent64) {.length = length, .flags = flags}; 2375 ea->count++; 2376 2377 return 0; 2378 } 2379 2380 static int coroutine_fn blockstatus_to_extents(BlockBackend *blk, 2381 uint64_t offset, uint64_t bytes, 2382 NBDExtentArray *ea) 2383 { 2384 while (bytes) { 2385 uint32_t flags; 2386 int64_t num; 2387 int ret = blk_co_block_status_above(blk, NULL, offset, bytes, &num, 2388 NULL, NULL); 2389 2390 if (ret < 0) { 2391 return ret; 2392 } 2393 2394 flags = (ret & BDRV_BLOCK_DATA ? 0 : NBD_STATE_HOLE) | 2395 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 2396 2397 if (nbd_extent_array_add(ea, num, flags) < 0) { 2398 return 0; 2399 } 2400 2401 offset += num; 2402 bytes -= num; 2403 } 2404 2405 return 0; 2406 } 2407 2408 static int coroutine_fn blockalloc_to_extents(BlockBackend *blk, 2409 uint64_t offset, uint64_t bytes, 2410 NBDExtentArray *ea) 2411 { 2412 while (bytes) { 2413 int64_t num; 2414 int ret = blk_co_is_allocated_above(blk, NULL, false, offset, bytes, 2415 &num); 2416 2417 if (ret < 0) { 2418 return ret; 2419 } 2420 2421 if (nbd_extent_array_add(ea, num, ret) < 0) { 2422 return 0; 2423 } 2424 2425 offset += num; 2426 bytes -= num; 2427 } 2428 2429 return 0; 2430 } 2431 2432 /* 2433 * nbd_co_send_extents 2434 * 2435 * @ea is converted to BE by the function 2436 * @last controls whether NBD_REPLY_FLAG_DONE is sent. 2437 */ 2438 static int coroutine_fn 2439 nbd_co_send_extents(NBDClient *client, NBDRequest *request, NBDExtentArray *ea, 2440 bool last, uint32_t context_id, Error **errp) 2441 { 2442 NBDReply hdr; 2443 NBDStructuredMeta meta; 2444 NBDExtendedMeta meta_ext; 2445 g_autofree NBDExtent32 *extents = NULL; 2446 uint16_t type; 2447 struct iovec iov[] = { {.iov_base = &hdr}, {0}, {0} }; 2448 2449 if (client->mode >= NBD_MODE_EXTENDED) { 2450 type = NBD_REPLY_TYPE_BLOCK_STATUS_EXT; 2451 2452 iov[1].iov_base = &meta_ext; 2453 iov[1].iov_len = sizeof(meta_ext); 2454 stl_be_p(&meta_ext.context_id, context_id); 2455 stl_be_p(&meta_ext.count, ea->count); 2456 2457 nbd_extent_array_convert_to_be(ea); 2458 iov[2].iov_base = ea->extents; 2459 iov[2].iov_len = ea->count * sizeof(ea->extents[0]); 2460 } else { 2461 type = NBD_REPLY_TYPE_BLOCK_STATUS; 2462 2463 iov[1].iov_base = &meta; 2464 iov[1].iov_len = sizeof(meta); 2465 stl_be_p(&meta.context_id, context_id); 2466 2467 extents = nbd_extent_array_convert_to_narrow(ea); 2468 iov[2].iov_base = extents; 2469 iov[2].iov_len = ea->count * sizeof(extents[0]); 2470 } 2471 2472 trace_nbd_co_send_extents(request->cookie, ea->count, context_id, 2473 ea->total_length, last); 2474 set_be_chunk(client, iov, 3, last ? NBD_REPLY_FLAG_DONE : 0, type, 2475 request); 2476 2477 return nbd_co_send_iov(client, iov, 3, errp); 2478 } 2479 2480 /* Get block status from the exported device and send it to the client */ 2481 static int 2482 coroutine_fn nbd_co_send_block_status(NBDClient *client, NBDRequest *request, 2483 BlockBackend *blk, uint64_t offset, 2484 uint64_t length, bool dont_fragment, 2485 bool last, uint32_t context_id, 2486 Error **errp) 2487 { 2488 int ret; 2489 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2490 g_autoptr(NBDExtentArray) ea = 2491 nbd_extent_array_new(nb_extents, client->mode); 2492 2493 if (context_id == NBD_META_ID_BASE_ALLOCATION) { 2494 ret = blockstatus_to_extents(blk, offset, length, ea); 2495 } else { 2496 ret = blockalloc_to_extents(blk, offset, length, ea); 2497 } 2498 if (ret < 0) { 2499 return nbd_co_send_chunk_error(client, request, -ret, 2500 "can't get block status", errp); 2501 } 2502 2503 return nbd_co_send_extents(client, request, ea, last, context_id, errp); 2504 } 2505 2506 /* Populate @ea from a dirty bitmap. */ 2507 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap, 2508 uint64_t offset, uint64_t length, 2509 NBDExtentArray *es) 2510 { 2511 int64_t start, dirty_start, dirty_count; 2512 int64_t end = offset + length; 2513 bool full = false; 2514 int64_t bound = es->extended ? INT64_MAX : INT32_MAX; 2515 2516 bdrv_dirty_bitmap_lock(bitmap); 2517 2518 for (start = offset; 2519 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, bound, 2520 &dirty_start, &dirty_count); 2521 start = dirty_start + dirty_count) 2522 { 2523 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) || 2524 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0)) 2525 { 2526 full = true; 2527 break; 2528 } 2529 } 2530 2531 if (!full) { 2532 /* last non dirty extent, nothing to do if array is now full */ 2533 (void) nbd_extent_array_add(es, end - start, 0); 2534 } 2535 2536 bdrv_dirty_bitmap_unlock(bitmap); 2537 } 2538 2539 static int coroutine_fn nbd_co_send_bitmap(NBDClient *client, 2540 NBDRequest *request, 2541 BdrvDirtyBitmap *bitmap, 2542 uint64_t offset, 2543 uint64_t length, bool dont_fragment, 2544 bool last, uint32_t context_id, 2545 Error **errp) 2546 { 2547 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2548 g_autoptr(NBDExtentArray) ea = 2549 nbd_extent_array_new(nb_extents, client->mode); 2550 2551 bitmap_to_extents(bitmap, offset, length, ea); 2552 2553 return nbd_co_send_extents(client, request, ea, last, context_id, errp); 2554 } 2555 2556 /* 2557 * nbd_co_block_status_payload_read 2558 * Called when a client wants a subset of negotiated contexts via a 2559 * BLOCK_STATUS payload. Check the payload for valid length and 2560 * contents. On success, return 0 with request updated to effective 2561 * length. If request was invalid but all payload consumed, return 0 2562 * with request->len and request->contexts->count set to 0 (which will 2563 * trigger an appropriate NBD_EINVAL response later on). Return 2564 * negative errno if the payload was not fully consumed. 2565 */ 2566 static int 2567 nbd_co_block_status_payload_read(NBDClient *client, NBDRequest *request, 2568 Error **errp) 2569 { 2570 uint64_t payload_len = request->len; 2571 g_autofree char *buf = NULL; 2572 size_t count, i, nr_bitmaps; 2573 uint32_t id; 2574 2575 if (payload_len > NBD_MAX_BUFFER_SIZE) { 2576 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)", 2577 request->len, NBD_MAX_BUFFER_SIZE); 2578 return -EINVAL; 2579 } 2580 2581 assert(client->contexts.exp == client->exp); 2582 nr_bitmaps = client->exp->nr_export_bitmaps; 2583 request->contexts = g_new0(NBDMetaContexts, 1); 2584 request->contexts->exp = client->exp; 2585 2586 if (payload_len % sizeof(uint32_t) || 2587 payload_len < sizeof(NBDBlockStatusPayload) || 2588 payload_len > (sizeof(NBDBlockStatusPayload) + 2589 sizeof(id) * client->contexts.count)) { 2590 goto skip; 2591 } 2592 2593 buf = g_malloc(payload_len); 2594 if (nbd_read(client->ioc, buf, payload_len, 2595 "CMD_BLOCK_STATUS data", errp) < 0) { 2596 return -EIO; 2597 } 2598 trace_nbd_co_receive_request_payload_received(request->cookie, 2599 payload_len); 2600 request->contexts->bitmaps = g_new0(bool, nr_bitmaps); 2601 count = (payload_len - sizeof(NBDBlockStatusPayload)) / sizeof(id); 2602 payload_len = 0; 2603 2604 for (i = 0; i < count; i++) { 2605 id = ldl_be_p(buf + sizeof(NBDBlockStatusPayload) + sizeof(id) * i); 2606 if (id == NBD_META_ID_BASE_ALLOCATION) { 2607 if (!client->contexts.base_allocation || 2608 request->contexts->base_allocation) { 2609 goto skip; 2610 } 2611 request->contexts->base_allocation = true; 2612 } else if (id == NBD_META_ID_ALLOCATION_DEPTH) { 2613 if (!client->contexts.allocation_depth || 2614 request->contexts->allocation_depth) { 2615 goto skip; 2616 } 2617 request->contexts->allocation_depth = true; 2618 } else { 2619 unsigned idx = id - NBD_META_ID_DIRTY_BITMAP; 2620 2621 if (idx >= nr_bitmaps || !client->contexts.bitmaps[idx] || 2622 request->contexts->bitmaps[idx]) { 2623 goto skip; 2624 } 2625 request->contexts->bitmaps[idx] = true; 2626 } 2627 } 2628 2629 request->len = ldq_be_p(buf); 2630 request->contexts->count = count; 2631 return 0; 2632 2633 skip: 2634 trace_nbd_co_receive_block_status_payload_compliance(request->from, 2635 request->len); 2636 request->len = request->contexts->count = 0; 2637 return nbd_drop(client->ioc, payload_len, errp); 2638 } 2639 2640 /* nbd_co_receive_request 2641 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2642 * connection right away, -EAGAIN to indicate we were interrupted and the 2643 * channel should be quiesced, and any other negative value to report an error 2644 * to the client (although the caller may still need to disconnect after 2645 * reporting the error). 2646 */ 2647 static int coroutine_fn nbd_co_receive_request(NBDRequestData *req, 2648 NBDRequest *request, 2649 Error **errp) 2650 { 2651 NBDClient *client = req->client; 2652 bool extended_with_payload; 2653 bool check_length = false; 2654 bool check_rofs = false; 2655 bool allocate_buffer = false; 2656 bool payload_okay = false; 2657 uint64_t payload_len = 0; 2658 int valid_flags = NBD_CMD_FLAG_FUA; 2659 int ret; 2660 2661 g_assert(qemu_in_coroutine()); 2662 ret = nbd_receive_request(client, request, errp); 2663 if (ret < 0) { 2664 return ret; 2665 } 2666 2667 trace_nbd_co_receive_request_decode_type(request->cookie, request->type, 2668 nbd_cmd_lookup(request->type)); 2669 extended_with_payload = client->mode >= NBD_MODE_EXTENDED && 2670 request->flags & NBD_CMD_FLAG_PAYLOAD_LEN; 2671 if (extended_with_payload) { 2672 payload_len = request->len; 2673 check_length = true; 2674 } 2675 2676 switch (request->type) { 2677 case NBD_CMD_DISC: 2678 /* Special case: we're going to disconnect without a reply, 2679 * whether or not flags, from, or len are bogus */ 2680 req->complete = true; 2681 return -EIO; 2682 2683 case NBD_CMD_READ: 2684 if (client->mode >= NBD_MODE_STRUCTURED) { 2685 valid_flags |= NBD_CMD_FLAG_DF; 2686 } 2687 check_length = true; 2688 allocate_buffer = true; 2689 break; 2690 2691 case NBD_CMD_WRITE: 2692 if (client->mode >= NBD_MODE_EXTENDED) { 2693 if (!extended_with_payload) { 2694 /* The client is noncompliant. Trace it, but proceed. */ 2695 trace_nbd_co_receive_ext_payload_compliance(request->from, 2696 request->len); 2697 } 2698 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN; 2699 } 2700 payload_okay = true; 2701 payload_len = request->len; 2702 check_length = true; 2703 allocate_buffer = true; 2704 check_rofs = true; 2705 break; 2706 2707 case NBD_CMD_FLUSH: 2708 break; 2709 2710 case NBD_CMD_TRIM: 2711 check_rofs = true; 2712 break; 2713 2714 case NBD_CMD_CACHE: 2715 check_length = true; 2716 break; 2717 2718 case NBD_CMD_WRITE_ZEROES: 2719 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2720 check_rofs = true; 2721 break; 2722 2723 case NBD_CMD_BLOCK_STATUS: 2724 if (extended_with_payload) { 2725 ret = nbd_co_block_status_payload_read(client, request, errp); 2726 if (ret < 0) { 2727 return ret; 2728 } 2729 /* payload now consumed */ 2730 check_length = false; 2731 payload_len = 0; 2732 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN; 2733 } else { 2734 request->contexts = &client->contexts; 2735 } 2736 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2737 break; 2738 2739 default: 2740 /* Unrecognized, will fail later */ 2741 ; 2742 } 2743 2744 /* Payload and buffer handling. */ 2745 if (!payload_len) { 2746 req->complete = true; 2747 } 2748 if (check_length && request->len > NBD_MAX_BUFFER_SIZE) { 2749 /* READ, WRITE, CACHE */ 2750 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)", 2751 request->len, NBD_MAX_BUFFER_SIZE); 2752 return -EINVAL; 2753 } 2754 if (payload_len && !payload_okay) { 2755 /* 2756 * For now, we don't support payloads on other commands; but 2757 * we can keep the connection alive by ignoring the payload. 2758 * We will fail the command later with NBD_EINVAL for the use 2759 * of an unsupported flag (and not for access beyond bounds). 2760 */ 2761 assert(request->type != NBD_CMD_WRITE); 2762 request->len = 0; 2763 } 2764 if (allocate_buffer) { 2765 /* READ, WRITE */ 2766 req->data = blk_try_blockalign(client->exp->common.blk, 2767 request->len); 2768 if (req->data == NULL) { 2769 error_setg(errp, "No memory"); 2770 return -ENOMEM; 2771 } 2772 } 2773 if (payload_len) { 2774 if (payload_okay) { 2775 /* WRITE */ 2776 assert(req->data); 2777 ret = nbd_read(client->ioc, req->data, payload_len, 2778 "CMD_WRITE data", errp); 2779 } else { 2780 ret = nbd_drop(client->ioc, payload_len, errp); 2781 } 2782 if (ret < 0) { 2783 return -EIO; 2784 } 2785 req->complete = true; 2786 trace_nbd_co_receive_request_payload_received(request->cookie, 2787 payload_len); 2788 } 2789 2790 /* Sanity checks. */ 2791 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && check_rofs) { 2792 /* WRITE, TRIM, WRITE_ZEROES */ 2793 error_setg(errp, "Export is read-only"); 2794 return -EROFS; 2795 } 2796 if (request->from > client->exp->size || 2797 request->len > client->exp->size - request->from) { 2798 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu64 2799 ", Size: %" PRIu64, request->from, request->len, 2800 client->exp->size); 2801 return (request->type == NBD_CMD_WRITE || 2802 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2803 } 2804 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2805 client->check_align)) { 2806 /* 2807 * The block layer gracefully handles unaligned requests, but 2808 * it's still worth tracing client non-compliance 2809 */ 2810 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2811 request->from, 2812 request->len, 2813 client->check_align); 2814 } 2815 if (request->flags & ~valid_flags) { 2816 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2817 nbd_cmd_lookup(request->type), request->flags); 2818 return -EINVAL; 2819 } 2820 2821 return 0; 2822 } 2823 2824 /* Send simple reply without a payload, or a structured error 2825 * @error_msg is ignored if @ret >= 0 2826 * Returns 0 if connection is still live, -errno on failure to talk to client 2827 */ 2828 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2829 NBDRequest *request, 2830 int ret, 2831 const char *error_msg, 2832 Error **errp) 2833 { 2834 if (client->mode >= NBD_MODE_STRUCTURED && ret < 0) { 2835 return nbd_co_send_chunk_error(client, request, -ret, error_msg, errp); 2836 } else if (client->mode >= NBD_MODE_EXTENDED) { 2837 return nbd_co_send_chunk_done(client, request, errp); 2838 } else { 2839 return nbd_co_send_simple_reply(client, request, ret < 0 ? -ret : 0, 2840 NULL, 0, errp); 2841 } 2842 } 2843 2844 /* Handle NBD_CMD_READ request. 2845 * Return -errno if sending fails. Other errors are reported directly to the 2846 * client as an error reply. */ 2847 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2848 uint8_t *data, Error **errp) 2849 { 2850 int ret; 2851 NBDExport *exp = client->exp; 2852 2853 assert(request->type == NBD_CMD_READ); 2854 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2855 2856 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2857 if (request->flags & NBD_CMD_FLAG_FUA) { 2858 ret = blk_co_flush(exp->common.blk); 2859 if (ret < 0) { 2860 return nbd_send_generic_reply(client, request, ret, 2861 "flush failed", errp); 2862 } 2863 } 2864 2865 if (client->mode >= NBD_MODE_STRUCTURED && 2866 !(request->flags & NBD_CMD_FLAG_DF) && request->len) 2867 { 2868 return nbd_co_send_sparse_read(client, request, request->from, 2869 data, request->len, errp); 2870 } 2871 2872 ret = blk_co_pread(exp->common.blk, request->from, request->len, data, 0); 2873 if (ret < 0) { 2874 return nbd_send_generic_reply(client, request, ret, 2875 "reading from file failed", errp); 2876 } 2877 2878 if (client->mode >= NBD_MODE_STRUCTURED) { 2879 if (request->len) { 2880 return nbd_co_send_chunk_read(client, request, request->from, data, 2881 request->len, true, errp); 2882 } else { 2883 return nbd_co_send_chunk_done(client, request, errp); 2884 } 2885 } else { 2886 return nbd_co_send_simple_reply(client, request, 0, 2887 data, request->len, errp); 2888 } 2889 } 2890 2891 /* 2892 * nbd_do_cmd_cache 2893 * 2894 * Handle NBD_CMD_CACHE request. 2895 * Return -errno if sending fails. Other errors are reported directly to the 2896 * client as an error reply. 2897 */ 2898 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2899 Error **errp) 2900 { 2901 int ret; 2902 NBDExport *exp = client->exp; 2903 2904 assert(request->type == NBD_CMD_CACHE); 2905 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2906 2907 ret = blk_co_preadv(exp->common.blk, request->from, request->len, 2908 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2909 2910 return nbd_send_generic_reply(client, request, ret, 2911 "caching data failed", errp); 2912 } 2913 2914 /* Handle NBD request. 2915 * Return -errno if sending fails. Other errors are reported directly to the 2916 * client as an error reply. */ 2917 static coroutine_fn int nbd_handle_request(NBDClient *client, 2918 NBDRequest *request, 2919 uint8_t *data, Error **errp) 2920 { 2921 int ret; 2922 int flags; 2923 NBDExport *exp = client->exp; 2924 char *msg; 2925 size_t i; 2926 bool inactive; 2927 2928 WITH_GRAPH_RDLOCK_GUARD() { 2929 inactive = bdrv_is_inactive(blk_bs(exp->common.blk)); 2930 if (inactive) { 2931 switch (request->type) { 2932 case NBD_CMD_READ: 2933 /* These commands are allowed on inactive nodes */ 2934 break; 2935 default: 2936 /* Return an error for the rest */ 2937 return nbd_send_generic_reply(client, request, -EPERM, 2938 "export is inactive", errp); 2939 } 2940 } 2941 } 2942 2943 switch (request->type) { 2944 case NBD_CMD_CACHE: 2945 return nbd_do_cmd_cache(client, request, errp); 2946 2947 case NBD_CMD_READ: 2948 return nbd_do_cmd_read(client, request, data, errp); 2949 2950 case NBD_CMD_WRITE: 2951 flags = 0; 2952 if (request->flags & NBD_CMD_FLAG_FUA) { 2953 flags |= BDRV_REQ_FUA; 2954 } 2955 assert(request->len <= NBD_MAX_BUFFER_SIZE); 2956 ret = blk_co_pwrite(exp->common.blk, request->from, request->len, data, 2957 flags); 2958 return nbd_send_generic_reply(client, request, ret, 2959 "writing to file failed", errp); 2960 2961 case NBD_CMD_WRITE_ZEROES: 2962 flags = 0; 2963 if (request->flags & NBD_CMD_FLAG_FUA) { 2964 flags |= BDRV_REQ_FUA; 2965 } 2966 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2967 flags |= BDRV_REQ_MAY_UNMAP; 2968 } 2969 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2970 flags |= BDRV_REQ_NO_FALLBACK; 2971 } 2972 ret = blk_co_pwrite_zeroes(exp->common.blk, request->from, request->len, 2973 flags); 2974 return nbd_send_generic_reply(client, request, ret, 2975 "writing to file failed", errp); 2976 2977 case NBD_CMD_DISC: 2978 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2979 abort(); 2980 2981 case NBD_CMD_FLUSH: 2982 ret = blk_co_flush(exp->common.blk); 2983 return nbd_send_generic_reply(client, request, ret, 2984 "flush failed", errp); 2985 2986 case NBD_CMD_TRIM: 2987 ret = blk_co_pdiscard(exp->common.blk, request->from, request->len); 2988 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) { 2989 ret = blk_co_flush(exp->common.blk); 2990 } 2991 return nbd_send_generic_reply(client, request, ret, 2992 "discard failed", errp); 2993 2994 case NBD_CMD_BLOCK_STATUS: 2995 assert(request->contexts); 2996 assert(client->mode >= NBD_MODE_EXTENDED || 2997 request->len <= UINT32_MAX); 2998 if (request->contexts->count) { 2999 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 3000 int contexts_remaining = request->contexts->count; 3001 3002 if (!request->len) { 3003 return nbd_send_generic_reply(client, request, -EINVAL, 3004 "need non-zero length", errp); 3005 } 3006 if (request->contexts->base_allocation) { 3007 ret = nbd_co_send_block_status(client, request, 3008 exp->common.blk, 3009 request->from, 3010 request->len, dont_fragment, 3011 !--contexts_remaining, 3012 NBD_META_ID_BASE_ALLOCATION, 3013 errp); 3014 if (ret < 0) { 3015 return ret; 3016 } 3017 } 3018 3019 if (request->contexts->allocation_depth) { 3020 ret = nbd_co_send_block_status(client, request, 3021 exp->common.blk, 3022 request->from, request->len, 3023 dont_fragment, 3024 !--contexts_remaining, 3025 NBD_META_ID_ALLOCATION_DEPTH, 3026 errp); 3027 if (ret < 0) { 3028 return ret; 3029 } 3030 } 3031 3032 assert(request->contexts->exp == client->exp); 3033 for (i = 0; i < client->exp->nr_export_bitmaps; i++) { 3034 if (!request->contexts->bitmaps[i]) { 3035 continue; 3036 } 3037 ret = nbd_co_send_bitmap(client, request, 3038 client->exp->export_bitmaps[i], 3039 request->from, request->len, 3040 dont_fragment, !--contexts_remaining, 3041 NBD_META_ID_DIRTY_BITMAP + i, errp); 3042 if (ret < 0) { 3043 return ret; 3044 } 3045 } 3046 3047 assert(!contexts_remaining); 3048 3049 return 0; 3050 } else if (client->contexts.count) { 3051 return nbd_send_generic_reply(client, request, -EINVAL, 3052 "CMD_BLOCK_STATUS payload not valid", 3053 errp); 3054 } else { 3055 return nbd_send_generic_reply(client, request, -EINVAL, 3056 "CMD_BLOCK_STATUS not negotiated", 3057 errp); 3058 } 3059 3060 default: 3061 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 3062 request->type); 3063 ret = nbd_send_generic_reply(client, request, -EINVAL, msg, 3064 errp); 3065 g_free(msg); 3066 return ret; 3067 } 3068 } 3069 3070 /* Owns a reference to the NBDClient passed as opaque. */ 3071 static coroutine_fn void nbd_trip(void *opaque) 3072 { 3073 NBDRequestData *req = opaque; 3074 NBDClient *client = req->client; 3075 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 3076 int ret; 3077 Error *local_err = NULL; 3078 3079 /* 3080 * Note that nbd_client_put() and client_close() must be called from the 3081 * main loop thread. Use aio_co_reschedule_self() to switch AioContext 3082 * before calling these functions. 3083 */ 3084 3085 trace_nbd_trip(); 3086 3087 qemu_mutex_lock(&client->lock); 3088 3089 if (client->closing) { 3090 goto done; 3091 } 3092 3093 if (client->quiescing) { 3094 /* 3095 * We're switching between AIO contexts. Don't attempt to receive a new 3096 * request and kick the main context which may be waiting for us. 3097 */ 3098 client->recv_coroutine = NULL; 3099 aio_wait_kick(); 3100 goto done; 3101 } 3102 3103 /* 3104 * nbd_co_receive_request() returns -EAGAIN when nbd_drained_begin() has 3105 * set client->quiescing but by the time we get back nbd_drained_end() may 3106 * have already cleared client->quiescing. In that case we try again 3107 * because nothing else will spawn an nbd_trip() coroutine until we set 3108 * client->recv_coroutine = NULL further down. 3109 */ 3110 do { 3111 assert(client->recv_coroutine == qemu_coroutine_self()); 3112 qemu_mutex_unlock(&client->lock); 3113 ret = nbd_co_receive_request(req, &request, &local_err); 3114 qemu_mutex_lock(&client->lock); 3115 } while (ret == -EAGAIN && !client->quiescing); 3116 3117 client->recv_coroutine = NULL; 3118 3119 if (client->closing) { 3120 /* 3121 * The client may be closed when we are blocked in 3122 * nbd_co_receive_request() 3123 */ 3124 goto done; 3125 } 3126 3127 if (ret == -EAGAIN) { 3128 goto done; 3129 } 3130 3131 nbd_client_receive_next_request(client); 3132 3133 if (ret == -EIO) { 3134 goto disconnect; 3135 } 3136 3137 qemu_mutex_unlock(&client->lock); 3138 qio_channel_set_cork(client->ioc, true); 3139 3140 if (ret < 0) { 3141 /* It wasn't -EIO, so, according to nbd_co_receive_request() 3142 * semantics, we should return the error to the client. */ 3143 Error *export_err = local_err; 3144 3145 local_err = NULL; 3146 ret = nbd_send_generic_reply(client, &request, -EINVAL, 3147 error_get_pretty(export_err), &local_err); 3148 error_free(export_err); 3149 } else { 3150 ret = nbd_handle_request(client, &request, req->data, &local_err); 3151 } 3152 if (request.contexts && request.contexts != &client->contexts) { 3153 assert(request.type == NBD_CMD_BLOCK_STATUS); 3154 g_free(request.contexts->bitmaps); 3155 g_free(request.contexts); 3156 } 3157 3158 qio_channel_set_cork(client->ioc, false); 3159 qemu_mutex_lock(&client->lock); 3160 3161 if (ret < 0) { 3162 error_prepend(&local_err, "Failed to send reply: "); 3163 goto disconnect; 3164 } 3165 3166 /* 3167 * We must disconnect after NBD_CMD_WRITE or BLOCK_STATUS with 3168 * payload if we did not read the payload. 3169 */ 3170 if (!req->complete) { 3171 error_setg(&local_err, "Request handling failed in intermediate state"); 3172 goto disconnect; 3173 } 3174 3175 done: 3176 nbd_request_put(req); 3177 3178 qemu_mutex_unlock(&client->lock); 3179 3180 if (!nbd_client_put_nonzero(client)) { 3181 aio_co_reschedule_self(qemu_get_aio_context()); 3182 nbd_client_put(client); 3183 } 3184 return; 3185 3186 disconnect: 3187 if (local_err) { 3188 error_reportf_err(local_err, "Disconnect client, due to: "); 3189 } 3190 3191 nbd_request_put(req); 3192 qemu_mutex_unlock(&client->lock); 3193 3194 aio_co_reschedule_self(qemu_get_aio_context()); 3195 client_close(client, true); 3196 nbd_client_put(client); 3197 } 3198 3199 /* 3200 * Runs in export AioContext and main loop thread. Caller must hold 3201 * client->lock. 3202 */ 3203 static void nbd_client_receive_next_request(NBDClient *client) 3204 { 3205 NBDRequestData *req; 3206 3207 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS && 3208 !client->quiescing) { 3209 nbd_client_get(client); 3210 req = nbd_request_get(client); 3211 client->recv_coroutine = qemu_coroutine_create(nbd_trip, req); 3212 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine); 3213 } 3214 } 3215 3216 static void nbd_handshake_timer_cb(void *opaque) 3217 { 3218 QIOChannel *ioc = opaque; 3219 3220 trace_nbd_handshake_timer_cb(); 3221 qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); 3222 } 3223 3224 static coroutine_fn void nbd_co_client_start(void *opaque) 3225 { 3226 NBDClient *client = opaque; 3227 Error *local_err = NULL; 3228 QEMUTimer *handshake_timer = NULL; 3229 3230 qemu_co_mutex_init(&client->send_lock); 3231 3232 /* 3233 * Create a timer to bound the time spent in negotiation. If the 3234 * timer expires, it is likely nbd_negotiate will fail because the 3235 * socket was shutdown. 3236 */ 3237 if (client->handshake_max_secs > 0) { 3238 handshake_timer = aio_timer_new(qemu_get_aio_context(), 3239 QEMU_CLOCK_REALTIME, 3240 SCALE_NS, 3241 nbd_handshake_timer_cb, 3242 client->sioc); 3243 timer_mod(handshake_timer, 3244 qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + 3245 client->handshake_max_secs * NANOSECONDS_PER_SECOND); 3246 } 3247 3248 if (nbd_negotiate(client, &local_err)) { 3249 if (local_err) { 3250 error_report_err(local_err); 3251 } 3252 timer_free(handshake_timer); 3253 client_close(client, false); 3254 return; 3255 } 3256 3257 timer_free(handshake_timer); 3258 WITH_QEMU_LOCK_GUARD(&client->lock) { 3259 nbd_client_receive_next_request(client); 3260 } 3261 } 3262 3263 /* 3264 * Create a new client listener using the given channel @sioc and @owner. 3265 * Begin servicing it in a coroutine. When the connection closes, call 3266 * @close_fn with an indication of whether the client completed negotiation 3267 * within @handshake_max_secs seconds (0 for unbounded). 3268 */ 3269 void nbd_client_new(QIOChannelSocket *sioc, 3270 uint32_t handshake_max_secs, 3271 QCryptoTLSCreds *tlscreds, 3272 const char *tlsauthz, 3273 void (*close_fn)(NBDClient *, bool), 3274 void *owner) 3275 { 3276 NBDClient *client; 3277 Coroutine *co; 3278 3279 client = g_new0(NBDClient, 1); 3280 qemu_mutex_init(&client->lock); 3281 client->refcount = 1; 3282 client->tlscreds = tlscreds; 3283 if (tlscreds) { 3284 object_ref(OBJECT(client->tlscreds)); 3285 } 3286 client->tlsauthz = g_strdup(tlsauthz); 3287 client->handshake_max_secs = handshake_max_secs; 3288 client->sioc = sioc; 3289 qio_channel_set_delay(QIO_CHANNEL(sioc), false); 3290 object_ref(OBJECT(client->sioc)); 3291 client->ioc = QIO_CHANNEL(sioc); 3292 object_ref(OBJECT(client->ioc)); 3293 client->close_fn = close_fn; 3294 client->owner = owner; 3295 3296 nbd_set_socket_send_buffer(sioc); 3297 3298 co = qemu_coroutine_create(nbd_co_client_start, client); 3299 qemu_coroutine_enter(co); 3300 } 3301 3302 void * 3303 nbd_client_owner(NBDClient *client) 3304 { 3305 return client->owner; 3306 } 3307