?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
block: Leave BDS.backing_{file,format} constant
[qemu.git] / nbd / server.c
blob982de67816a7b4d4e56fba0544244f95d3f9b5a5
1 /*
2 * Copyright (C) 2016-2018 Red Hat, Inc.
3 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
4 *
5 * Network Block Device Server Side
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; under version 2 of the License.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include "qemu/osdep.h"
21 #include "qapi/error.h"
22 #include "qemu/queue.h"
23 #include "trace.h"
24 #include "nbd-internal.h"
25 #include "qemu/units.h"
26
27 #define NBD_META_ID_BASE_ALLOCATION 0
28 #define NBD_META_ID_DIRTY_BITMAP 1
29
30 /*
31 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical
32 * constant. If an increase is needed, note that the NBD protocol
33 * recommends no larger than 32 mb, so that the client won't consider
34 * the reply as a denial of service attack.
35 */
36 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8)
37
38 static int system_errno_to_nbd_errno(int err)
39 {
40 switch (err) {
41 case 0:
42 return NBD_SUCCESS;
43 case EPERM:
44 case EROFS:
45 return NBD_EPERM;
46 case EIO:
47 return NBD_EIO;
48 case ENOMEM:
49 return NBD_ENOMEM;
50 #ifdef EDQUOT
51 case EDQUOT:
52 #endif
53 case EFBIG:
54 case ENOSPC:
55 return NBD_ENOSPC;
56 case EOVERFLOW:
57 return NBD_EOVERFLOW;
58 case ENOTSUP:
59 #if ENOTSUP != EOPNOTSUPP
60 case EOPNOTSUPP:
61 #endif
62 return NBD_ENOTSUP;
63 case ESHUTDOWN:
64 return NBD_ESHUTDOWN;
65 case EINVAL:
66 default:
67 return NBD_EINVAL;
68 }
69 }
70
71 /* Definitions for opaque data types */
72
73 typedef struct NBDRequestData NBDRequestData;
74
75 struct NBDRequestData {
76 QSIMPLEQ_ENTRY(NBDRequestData) entry;
77 NBDClient *client;
78 uint8_t *data;
79 bool complete;
80 };
81
82 struct NBDExport {
83 int refcount;
84 void (*close)(NBDExport *exp);
85
86 BlockBackend *blk;
87 char *name;
88 char *description;
89 uint64_t dev_offset;
90 uint64_t size;
91 uint16_t nbdflags;
92 QTAILQ_HEAD(, NBDClient) clients;
93 QTAILQ_ENTRY(NBDExport) next;
94
95 AioContext *ctx;
96
97 BlockBackend *eject_notifier_blk;
98 Notifier eject_notifier;
99
100 BdrvDirtyBitmap *export_bitmap;
101 char *export_bitmap_context;
102 };
103
104 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
105 static QTAILQ_HEAD(, NBDExport) closed_exports =
106 QTAILQ_HEAD_INITIALIZER(closed_exports);
107
108 /* NBDExportMetaContexts represents a list of contexts to be exported,
109 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for
110 * NBD_OPT_LIST_META_CONTEXT. */
111 typedef struct NBDExportMetaContexts {
112 NBDExport *exp;
113 bool valid; /* means that negotiation of the option finished without
114 errors */
115 bool base_allocation; /* export base:allocation context (block status) */
116 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */
117 } NBDExportMetaContexts;
118
119 struct NBDClient {
120 int refcount;
121 void (*close_fn)(NBDClient *client, bool negotiated);
122
123 NBDExport *exp;
124 QCryptoTLSCreds *tlscreds;
125 char *tlsauthz;
126 QIOChannelSocket *sioc; /* The underlying data channel */
127 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
128
129 Coroutine *recv_coroutine;
130
131 CoMutex send_lock;
132 Coroutine *send_coroutine;
133
134 QTAILQ_ENTRY(NBDClient) next;
135 int nb_requests;
136 bool closing;
137
138 uint32_t check_align; /* If non-zero, check for aligned client requests */
139
140 bool structured_reply;
141 NBDExportMetaContexts export_meta;
142
143 uint32_t opt; /* Current option being negotiated */
144 uint32_t optlen; /* remaining length of data in ioc for the option being
145 negotiated now */
146 };
147
148 static void nbd_client_receive_next_request(NBDClient *client);
149
150 /* Basic flow for negotiation
151
152 Server Client
153 Negotiate
154
155 or
156
157 Server Client
158 Negotiate #1
159 Option
160 Negotiate #2
161
162 ----
163
164 followed by
165
166 Server Client
167 Request
168 Response
169 Request
170 Response
171 ...
172 ...
173 Request (type == 2)
174
175 */
176
177 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
178 uint32_t type, uint32_t length)
179 {
180 stq_be_p(&rep->magic, NBD_REP_MAGIC);
181 stl_be_p(&rep->option, option);
182 stl_be_p(&rep->type, type);
183 stl_be_p(&rep->length, length);
184 }
185
186 /* Send a reply header, including length, but no payload.
187 * Return -errno on error, 0 on success. */
188 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
189 uint32_t len, Error **errp)
190 {
191 NBDOptionReply rep;
192
193 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),
194 type, nbd_rep_lookup(type), len);
195
196 assert(len < NBD_MAX_BUFFER_SIZE);
197
198 set_be_option_rep(&rep, client->opt, type, len);
199 return nbd_write(client->ioc, &rep, sizeof(rep), errp);
200 }
201
202 /* Send a reply header with default 0 length.
203 * Return -errno on error, 0 on success. */
204 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
205 Error **errp)
206 {
207 return nbd_negotiate_send_rep_len(client, type, 0, errp);
208 }
209
210 /* Send an error reply.
211 * Return -errno on error, 0 on success. */
212 static int GCC_FMT_ATTR(4, 0)
213 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
214 Error **errp, const char *fmt, va_list va)
215 {
216 ERRP_GUARD();
217 g_autofree char *msg = NULL;
218 int ret;
219 size_t len;
220
221 msg = g_strdup_vprintf(fmt, va);
222 len = strlen(msg);
223 assert(len < NBD_MAX_STRING_SIZE);
224 trace_nbd_negotiate_send_rep_err(msg);
225 ret = nbd_negotiate_send_rep_len(client, type, len, errp);
226 if (ret < 0) {
227 return ret;
228 }
229 if (nbd_write(client->ioc, msg, len, errp) < 0) {
230 error_prepend(errp, "write failed (error message): ");
231 return -EIO;
232 }
233
234 return 0;
235 }
236
237 /*
238 * Return a malloc'd copy of @name suitable for use in an error reply.
239 */
240 static char *
241 nbd_sanitize_name(const char *name)
242 {
243 if (strnlen(name, 80) < 80) {
244 return g_strdup(name);
245 }
246 /* XXX Should we also try to sanitize any control characters? */
247 return g_strdup_printf("%.80s...", name);
248 }
249
250 /* Send an error reply.
251 * Return -errno on error, 0 on success. */
252 static int GCC_FMT_ATTR(4, 5)
253 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
254 Error **errp, const char *fmt, ...)
255 {
256 va_list va;
257 int ret;
258
259 va_start(va, fmt);
260 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
261 va_end(va);
262 return ret;
263 }
264
265 /* Drop remainder of the current option, and send a reply with the
266 * given error type and message. Return -errno on read or write
267 * failure; or 0 if connection is still live. */
268 static int GCC_FMT_ATTR(4, 0)
269 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
270 const char *fmt, va_list va)
271 {
272 int ret = nbd_drop(client->ioc, client->optlen, errp);
273
274 client->optlen = 0;
275 if (!ret) {
276 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
277 }
278 return ret;
279 }
280
281 static int GCC_FMT_ATTR(4, 5)
282 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
283 const char *fmt, ...)
284 {
285 int ret;
286 va_list va;
287
288 va_start(va, fmt);
289 ret = nbd_opt_vdrop(client, type, errp, fmt, va);
290 va_end(va);
291
292 return ret;
293 }
294
295 static int GCC_FMT_ATTR(3, 4)
296 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
297 {
298 int ret;
299 va_list va;
300
301 va_start(va, fmt);
302 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);
303 va_end(va);
304
305 return ret;
306 }
307
308 /* Read size bytes from the unparsed payload of the current option.
309 * Return -errno on I/O error, 0 if option was completely handled by
310 * sending a reply about inconsistent lengths, or 1 on success. */
311 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
312 Error **errp)
313 {
314 if (size > client->optlen) {
315 return nbd_opt_invalid(client, errp,
316 "Inconsistent lengths in option %s",
317 nbd_opt_lookup(client->opt));
318 }
319 client->optlen -= size;
320 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1;
321 }
322
323 /* Drop size bytes from the unparsed payload of the current option.
324 * Return -errno on I/O error, 0 if option was completely handled by
325 * sending a reply about inconsistent lengths, or 1 on success. */
326 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
327 {
328 if (size > client->optlen) {
329 return nbd_opt_invalid(client, errp,
330 "Inconsistent lengths in option %s",
331 nbd_opt_lookup(client->opt));
332 }
333 client->optlen -= size;
334 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
335 }
336
337 /* nbd_opt_read_name
338 *
339 * Read a string with the format:
340 * uint32_t len (<= NBD_MAX_STRING_SIZE)
341 * len bytes string (not 0-terminated)
342 *
343 * On success, @name will be allocated.
344 * If @length is non-null, it will be set to the actual string length.
345 *
346 * Return -errno on I/O error, 0 if option was completely handled by
347 * sending a reply about inconsistent lengths, or 1 on success.
348 */
349 static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
350 Error **errp)
351 {
352 int ret;
353 uint32_t len;
354 g_autofree char *local_name = NULL;
355
356 *name = NULL;
357 ret = nbd_opt_read(client, &len, sizeof(len), errp);
358 if (ret <= 0) {
359 return ret;
360 }
361 len = cpu_to_be32(len);
362
363 if (len > NBD_MAX_STRING_SIZE) {
364 return nbd_opt_invalid(client, errp,
365 "Invalid name length: %" PRIu32, len);
366 }
367
368 local_name = g_malloc(len + 1);
369 ret = nbd_opt_read(client, local_name, len, errp);
370 if (ret <= 0) {
371 return ret;
372 }
373 local_name[len] = '\0';
374
375 if (length) {
376 *length = len;
377 }
378 *name = g_steal_pointer(&local_name);
379
380 return 1;
381 }
382
383 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
384 * Return -errno on error, 0 on success. */
385 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
386 Error **errp)
387 {
388 ERRP_GUARD();
389 size_t name_len, desc_len;
390 uint32_t len;
391 const char *name = exp->name ? exp->name : "";
392 const char *desc = exp->description ? exp->description : "";
393 QIOChannel *ioc = client->ioc;
394 int ret;
395
396 trace_nbd_negotiate_send_rep_list(name, desc);
397 name_len = strlen(name);
398 desc_len = strlen(desc);
399 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE);
400 len = name_len + desc_len + sizeof(len);
401 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
402 if (ret < 0) {
403 return ret;
404 }
405
406 len = cpu_to_be32(name_len);
407 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
408 error_prepend(errp, "write failed (name length): ");
409 return -EINVAL;
410 }
411
412 if (nbd_write(ioc, name, name_len, errp) < 0) {
413 error_prepend(errp, "write failed (name buffer): ");
414 return -EINVAL;
415 }
416
417 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
418 error_prepend(errp, "write failed (description buffer): ");
419 return -EINVAL;
420 }
421
422 return 0;
423 }
424
425 /* Process the NBD_OPT_LIST command, with a potential series of replies.
426 * Return -errno on error, 0 on success. */
427 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
428 {
429 NBDExport *exp;
430 assert(client->opt == NBD_OPT_LIST);
431
432 /* For each export, send a NBD_REP_SERVER reply. */
433 QTAILQ_FOREACH(exp, &exports, next) {
434 if (nbd_negotiate_send_rep_list(client, exp, errp)) {
435 return -EINVAL;
436 }
437 }
438 /* Finish with a NBD_REP_ACK. */
439 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
440 }
441
442 static void nbd_check_meta_export(NBDClient *client)
443 {
444 client->export_meta.valid &= client->exp == client->export_meta.exp;
445 }
446
447 /* Send a reply to NBD_OPT_EXPORT_NAME.
448 * Return -errno on error, 0 on success. */
449 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
450 Error **errp)
451 {
452 ERRP_GUARD();
453 g_autofree char *name = NULL;
454 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
455 size_t len;
456 int ret;
457 uint16_t myflags;
458
459 /* Client sends:
460 [20 .. xx] export name (length bytes)
461 Server replies:
462 [ 0 .. 7] size
463 [ 8 .. 9] export flags
464 [10 .. 133] reserved (0) [unless no_zeroes]
465 */
466 trace_nbd_negotiate_handle_export_name();
467 if (client->optlen > NBD_MAX_STRING_SIZE) {
468 error_setg(errp, "Bad length received");
469 return -EINVAL;
470 }
471 name = g_malloc(client->optlen + 1);
472 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) {
473 return -EIO;
474 }
475 name[client->optlen] = '\0';
476 client->optlen = 0;
477
478 trace_nbd_negotiate_handle_export_name_request(name);
479
480 client->exp = nbd_export_find(name);
481 if (!client->exp) {
482 error_setg(errp, "export not found");
483 return -EINVAL;
484 }
485
486 myflags = client->exp->nbdflags;
487 if (client->structured_reply) {
488 myflags |= NBD_FLAG_SEND_DF;
489 }
490 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags);
491 stq_be_p(buf, client->exp->size);
492 stw_be_p(buf + 8, myflags);
493 len = no_zeroes ? 10 : sizeof(buf);
494 ret = nbd_write(client->ioc, buf, len, errp);
495 if (ret < 0) {
496 error_prepend(errp, "write failed: ");
497 return ret;
498 }
499
500 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
501 nbd_export_get(client->exp);
502 nbd_check_meta_export(client);
503
504 return 0;
505 }
506
507 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
508 * The buffer does NOT include the info type prefix.
509 * Return -errno on error, 0 if ready to send more. */
510 static int nbd_negotiate_send_info(NBDClient *client,
511 uint16_t info, uint32_t length, void *buf,
512 Error **errp)
513 {
514 int rc;
515
516 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
517 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
518 sizeof(info) + length, errp);
519 if (rc < 0) {
520 return rc;
521 }
522 info = cpu_to_be16(info);
523 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
524 return -EIO;
525 }
526 if (nbd_write(client->ioc, buf, length, errp) < 0) {
527 return -EIO;
528 }
529 return 0;
530 }
531
532 /* nbd_reject_length: Handle any unexpected payload.
533 * @fatal requests that we quit talking to the client, even if we are able
534 * to successfully send an error reply.
535 * Return:
536 * -errno transmission error occurred or @fatal was requested, errp is set
537 * 0 error message successfully sent to client, errp is not set
538 */
539 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
540 {
541 int ret;
542
543 assert(client->optlen);
544 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",
545 nbd_opt_lookup(client->opt));
546 if (fatal && !ret) {
547 error_setg(errp, "option '%s' has unexpected length",
548 nbd_opt_lookup(client->opt));
549 return -EINVAL;
550 }
551 return ret;
552 }
553
554 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
555 * Return -errno on error, 0 if ready for next option, and 1 to move
556 * into transmission phase. */
557 static int nbd_negotiate_handle_info(NBDClient *client, Error **errp)
558 {
559 int rc;
560 g_autofree char *name = NULL;
561 NBDExport *exp;
562 uint16_t requests;
563 uint16_t request;
564 uint32_t namelen;
565 bool sendname = false;
566 bool blocksize = false;
567 uint32_t sizes[3];
568 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
569 uint32_t check_align = 0;
570 uint16_t myflags;
571
572 /* Client sends:
573 4 bytes: L, name length (can be 0)
574 L bytes: export name
575 2 bytes: N, number of requests (can be 0)
576 N * 2 bytes: N requests
577 */
578 rc = nbd_opt_read_name(client, &name, &namelen, errp);
579 if (rc <= 0) {
580 return rc;
581 }
582 trace_nbd_negotiate_handle_export_name_request(name);
583
584 rc = nbd_opt_read(client, &requests, sizeof(requests), errp);
585 if (rc <= 0) {
586 return rc;
587 }
588 requests = be16_to_cpu(requests);
589 trace_nbd_negotiate_handle_info_requests(requests);
590 while (requests--) {
591 rc = nbd_opt_read(client, &request, sizeof(request), errp);
592 if (rc <= 0) {
593 return rc;
594 }
595 request = be16_to_cpu(request);
596 trace_nbd_negotiate_handle_info_request(request,
597 nbd_info_lookup(request));
598 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
599 * everything else is either a request we don't know or
600 * something we send regardless of request */
601 switch (request) {
602 case NBD_INFO_NAME:
603 sendname = true;
604 break;
605 case NBD_INFO_BLOCK_SIZE:
606 blocksize = true;
607 break;
608 }
609 }
610 if (client->optlen) {
611 return nbd_reject_length(client, false, errp);
612 }
613
614 exp = nbd_export_find(name);
615 if (!exp) {
616 g_autofree char *sane_name = nbd_sanitize_name(name);
617
618 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
619 errp, "export '%s' not present",
620 sane_name);
621 }
622
623 /* Don't bother sending NBD_INFO_NAME unless client requested it */
624 if (sendname) {
625 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
626 errp);
627 if (rc < 0) {
628 return rc;
629 }
630 }
631
632 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
633 * client request */
634 if (exp->description) {
635 size_t len = strlen(exp->description);
636
637 assert(len <= NBD_MAX_STRING_SIZE);
638 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
639 len, exp->description, errp);
640 if (rc < 0) {
641 return rc;
642 }
643 }
644
645 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
646 * according to whether the client requested it, and according to
647 * whether this is OPT_INFO or OPT_GO. */
648 /* minimum - 1 for back-compat, or actual if client will obey it. */
649 if (client->opt == NBD_OPT_INFO || blocksize) {
650 check_align = sizes[0] = blk_get_request_alignment(exp->blk);
651 } else {
652 sizes[0] = 1;
653 }
654 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE);
655 /* preferred - Hard-code to 4096 for now.
656 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
657 sizes[1] = MAX(4096, sizes[0]);
658 /* maximum - At most 32M, but smaller as appropriate. */
659 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
660 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
661 sizes[0] = cpu_to_be32(sizes[0]);
662 sizes[1] = cpu_to_be32(sizes[1]);
663 sizes[2] = cpu_to_be32(sizes[2]);
664 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
665 sizeof(sizes), sizes, errp);
666 if (rc < 0) {
667 return rc;
668 }
669
670 /* Send NBD_INFO_EXPORT always */
671 myflags = exp->nbdflags;
672 if (client->structured_reply) {
673 myflags |= NBD_FLAG_SEND_DF;
674 }
675 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags);
676 stq_be_p(buf, exp->size);
677 stw_be_p(buf + 8, myflags);
678 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
679 sizeof(buf), buf, errp);
680 if (rc < 0) {
681 return rc;
682 }
683
684 /*
685 * If the client is just asking for NBD_OPT_INFO, but forgot to
686 * request block sizes in a situation that would impact
687 * performance, then return an error. But for NBD_OPT_GO, we
688 * tolerate all clients, regardless of alignments.
689 */
690 if (client->opt == NBD_OPT_INFO && !blocksize &&
691 blk_get_request_alignment(exp->blk) > 1) {
692 return nbd_negotiate_send_rep_err(client,
693 NBD_REP_ERR_BLOCK_SIZE_REQD,
694 errp,
695 "request NBD_INFO_BLOCK_SIZE to "
696 "use this export");
697 }
698
699 /* Final reply */
700 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
701 if (rc < 0) {
702 return rc;
703 }
704
705 if (client->opt == NBD_OPT_GO) {
706 client->exp = exp;
707 client->check_align = check_align;
708 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
709 nbd_export_get(client->exp);
710 nbd_check_meta_export(client);
711 rc = 1;
712 }
713 return rc;
714 }
715
716
717 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
718 * new channel for all further (now-encrypted) communication. */
719 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
720 Error **errp)
721 {
722 QIOChannel *ioc;
723 QIOChannelTLS *tioc;
724 struct NBDTLSHandshakeData data = { 0 };
725
726 assert(client->opt == NBD_OPT_STARTTLS);
727
728 trace_nbd_negotiate_handle_starttls();
729 ioc = client->ioc;
730
731 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
732 return NULL;
733 }
734
735 tioc = qio_channel_tls_new_server(ioc,
736 client->tlscreds,
737 client->tlsauthz,
738 errp);
739 if (!tioc) {
740 return NULL;
741 }
742
743 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
744 trace_nbd_negotiate_handle_starttls_handshake();
745 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
746 qio_channel_tls_handshake(tioc,
747 nbd_tls_handshake,
748 &data,
749 NULL,
750 NULL);
751
752 if (!data.complete) {
753 g_main_loop_run(data.loop);
754 }
755 g_main_loop_unref(data.loop);
756 if (data.error) {
757 object_unref(OBJECT(tioc));
758 error_propagate(errp, data.error);
759 return NULL;
760 }
761
762 return QIO_CHANNEL(tioc);
763 }
764
765 /* nbd_negotiate_send_meta_context
766 *
767 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
768 *
769 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
770 */
771 static int nbd_negotiate_send_meta_context(NBDClient *client,
772 const char *context,
773 uint32_t context_id,
774 Error **errp)
775 {
776 NBDOptionReplyMetaContext opt;
777 struct iovec iov[] = {
778 {.iov_base = &opt, .iov_len = sizeof(opt)},
779 {.iov_base = (void *)context, .iov_len = strlen(context)}
780 };
781
782 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE);
783 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
784 context_id = 0;
785 }
786
787 trace_nbd_negotiate_meta_query_reply(context, context_id);
788 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
789 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
790 stl_be_p(&opt.context_id, context_id);
791
792 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
793 }
794
795 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern.
796 * @match is never set to false.
797 *
798 * Return -errno on I/O error, 0 if option was completely handled by
799 * sending a reply about inconsistent lengths, or 1 on success.
800 *
801 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
802 * It only means that there are no errors.
803 */
804 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match,
805 Error **errp)
806 {
807 int ret;
808 char *query;
809 size_t len = strlen(pattern);
810
811 assert(len);
812
813 query = g_malloc(len);
814 ret = nbd_opt_read(client, query, len, errp);
815 if (ret <= 0) {
816 g_free(query);
817 return ret;
818 }
819
820 if (strncmp(query, pattern, len) == 0) {
821 trace_nbd_negotiate_meta_query_parse(pattern);
822 *match = true;
823 } else {
824 trace_nbd_negotiate_meta_query_skip("pattern not matched");
825 }
826 g_free(query);
827
828 return 1;
829 }
830
831 /*
832 * Read @len bytes, and set @match to true if they match @pattern, or if @len
833 * is 0 and the client is performing _LIST_. @match is never set to false.
834 *
835 * Return -errno on I/O error, 0 if option was completely handled by
836 * sending a reply about inconsistent lengths, or 1 on success.
837 *
838 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
839 * It only means that there are no errors.
840 */
841 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
842 uint32_t len, bool *match, Error **errp)
843 {
844 if (len == 0) {
845 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
846 *match = true;
847 }
848 trace_nbd_negotiate_meta_query_parse("empty");
849 return 1;
850 }
851
852 if (len != strlen(pattern)) {
853 trace_nbd_negotiate_meta_query_skip("different lengths");
854 return nbd_opt_skip(client, len, errp);
855 }
856
857 return nbd_meta_pattern(client, pattern, match, errp);
858 }
859
860 /* nbd_meta_base_query
861 *
862 * Handle queries to 'base' namespace. For now, only the base:allocation
863 * context is available. 'len' is the amount of text remaining to be read from
864 * the current name, after the 'base:' portion has been stripped.
865 *
866 * Return -errno on I/O error, 0 if option was completely handled by
867 * sending a reply about inconsistent lengths, or 1 on success.
868 */
869 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
870 uint32_t len, Error **errp)
871 {
872 return nbd_meta_empty_or_pattern(client, "allocation", len,
873 &meta->base_allocation, errp);
874 }
875
876 /* nbd_meta_bitmap_query
877 *
878 * Handle query to 'qemu:' namespace.
879 * @len is the amount of text remaining to be read from the current name, after
880 * the 'qemu:' portion has been stripped.
881 *
882 * Return -errno on I/O error, 0 if option was completely handled by
883 * sending a reply about inconsistent lengths, or 1 on success. */
884 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
885 uint32_t len, Error **errp)
886 {
887 bool dirty_bitmap = false;
888 size_t dirty_bitmap_len = strlen("dirty-bitmap:");
889 int ret;
890
891 if (!meta->exp->export_bitmap) {
892 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported");
893 return nbd_opt_skip(client, len, errp);
894 }
895
896 if (len == 0) {
897 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
898 meta->bitmap = true;
899 }
900 trace_nbd_negotiate_meta_query_parse("empty");
901 return 1;
902 }
903
904 if (len < dirty_bitmap_len) {
905 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
906 return nbd_opt_skip(client, len, errp);
907 }
908
909 len -= dirty_bitmap_len;
910 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp);
911 if (ret <= 0) {
912 return ret;
913 }
914 if (!dirty_bitmap) {
915 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
916 return nbd_opt_skip(client, len, errp);
917 }
918
919 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
920
921 return nbd_meta_empty_or_pattern(
922 client, meta->exp->export_bitmap_context +
923 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp);
924 }
925
926 /* nbd_negotiate_meta_query
927 *
928 * Parse namespace name and call corresponding function to parse body of the
929 * query.
930 *
931 * The only supported namespaces are 'base' and 'qemu'.
932 *
933 * The function aims not wasting time and memory to read long unknown namespace
934 * names.
935 *
936 * Return -errno on I/O error, 0 if option was completely handled by
937 * sending a reply about inconsistent lengths, or 1 on success. */
938 static int nbd_negotiate_meta_query(NBDClient *client,
939 NBDExportMetaContexts *meta, Error **errp)
940 {
941 /*
942 * Both 'qemu' and 'base' namespaces have length = 5 including a
943 * colon. If another length namespace is later introduced, this
944 * should certainly be refactored.
945 */
946 int ret;
947 size_t ns_len = 5;
948 char ns[5];
949 uint32_t len;
950
951 ret = nbd_opt_read(client, &len, sizeof(len), errp);
952 if (ret <= 0) {
953 return ret;
954 }
955 len = cpu_to_be32(len);
956
957 if (len > NBD_MAX_STRING_SIZE) {
958 trace_nbd_negotiate_meta_query_skip("length too long");
959 return nbd_opt_skip(client, len, errp);
960 }
961 if (len < ns_len) {
962 trace_nbd_negotiate_meta_query_skip("length too short");
963 return nbd_opt_skip(client, len, errp);
964 }
965
966 len -= ns_len;
967 ret = nbd_opt_read(client, ns, ns_len, errp);
968 if (ret <= 0) {
969 return ret;
970 }
971
972 if (!strncmp(ns, "base:", ns_len)) {
973 trace_nbd_negotiate_meta_query_parse("base:");
974 return nbd_meta_base_query(client, meta, len, errp);
975 } else if (!strncmp(ns, "qemu:", ns_len)) {
976 trace_nbd_negotiate_meta_query_parse("qemu:");
977 return nbd_meta_qemu_query(client, meta, len, errp);
978 }
979
980 trace_nbd_negotiate_meta_query_skip("unknown namespace");
981 return nbd_opt_skip(client, len, errp);
982 }
983
984 /* nbd_negotiate_meta_queries
985 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
986 *
987 * Return -errno on I/O error, or 0 if option was completely handled. */
988 static int nbd_negotiate_meta_queries(NBDClient *client,
989 NBDExportMetaContexts *meta, Error **errp)
990 {
991 int ret;
992 g_autofree char *export_name = NULL;
993 NBDExportMetaContexts local_meta;
994 uint32_t nb_queries;
995 int i;
996
997 if (!client->structured_reply) {
998 return nbd_opt_invalid(client, errp,
999 "request option '%s' when structured reply "
1000 "is not negotiated",
1001 nbd_opt_lookup(client->opt));
1002 }
1003
1004 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
1005 /* Only change the caller's meta on SET. */
1006 meta = &local_meta;
1007 }
1008
1009 memset(meta, 0, sizeof(*meta));
1010
1011 ret = nbd_opt_read_name(client, &export_name, NULL, errp);
1012 if (ret <= 0) {
1013 return ret;
1014 }
1015
1016 meta->exp = nbd_export_find(export_name);
1017 if (meta->exp == NULL) {
1018 g_autofree char *sane_name = nbd_sanitize_name(export_name);
1019
1020 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
1021 "export '%s' not present", sane_name);
1022 }
1023
1024 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp);
1025 if (ret <= 0) {
1026 return ret;
1027 }
1028 nb_queries = cpu_to_be32(nb_queries);
1029 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
1030 export_name, nb_queries);
1031
1032 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
1033 /* enable all known contexts */
1034 meta->base_allocation = true;
1035 meta->bitmap = !!meta->exp->export_bitmap;
1036 } else {
1037 for (i = 0; i < nb_queries; ++i) {
1038 ret = nbd_negotiate_meta_query(client, meta, errp);
1039 if (ret <= 0) {
1040 return ret;
1041 }
1042 }
1043 }
1044
1045 if (meta->base_allocation) {
1046 ret = nbd_negotiate_send_meta_context(client, "base:allocation",
1047 NBD_META_ID_BASE_ALLOCATION,
1048 errp);
1049 if (ret < 0) {
1050 return ret;
1051 }
1052 }
1053
1054 if (meta->bitmap) {
1055 ret = nbd_negotiate_send_meta_context(client,
1056 meta->exp->export_bitmap_context,
1057 NBD_META_ID_DIRTY_BITMAP,
1058 errp);
1059 if (ret < 0) {
1060 return ret;
1061 }
1062 }
1063
1064 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1065 if (ret == 0) {
1066 meta->valid = true;
1067 }
1068
1069 return ret;
1070 }
1071
1072 /* nbd_negotiate_options
1073 * Process all NBD_OPT_* client option commands, during fixed newstyle
1074 * negotiation.
1075 * Return:
1076 * -errno on error, errp is set
1077 * 0 on successful negotiation, errp is not set
1078 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1079 * errp is not set
1080 */
1081 static int nbd_negotiate_options(NBDClient *client, Error **errp)
1082 {
1083 uint32_t flags;
1084 bool fixedNewstyle = false;
1085 bool no_zeroes = false;
1086
1087 /* Client sends:
1088 [ 0 .. 3] client flags
1089
1090 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
1091 [ 0 .. 7] NBD_OPTS_MAGIC
1092 [ 8 .. 11] NBD option
1093 [12 .. 15] Data length
1094 ... Rest of request
1095
1096 [ 0 .. 7] NBD_OPTS_MAGIC
1097 [ 8 .. 11] Second NBD option
1098 [12 .. 15] Data length
1099 ... Rest of request
1100 */
1101
1102 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) {
1103 return -EIO;
1104 }
1105 trace_nbd_negotiate_options_flags(flags);
1106 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
1107 fixedNewstyle = true;
1108 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
1109 }
1110 if (flags & NBD_FLAG_C_NO_ZEROES) {
1111 no_zeroes = true;
1112 flags &= ~NBD_FLAG_C_NO_ZEROES;
1113 }
1114 if (flags != 0) {
1115 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
1116 return -EINVAL;
1117 }
1118
1119 while (1) {
1120 int ret;
1121 uint32_t option, length;
1122 uint64_t magic;
1123
1124 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) {
1125 return -EINVAL;
1126 }
1127 trace_nbd_negotiate_options_check_magic(magic);
1128 if (magic != NBD_OPTS_MAGIC) {
1129 error_setg(errp, "Bad magic received");
1130 return -EINVAL;
1131 }
1132
1133 if (nbd_read32(client->ioc, &option, "option", errp) < 0) {
1134 return -EINVAL;
1135 }
1136 client->opt = option;
1137
1138 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) {
1139 return -EINVAL;
1140 }
1141 assert(!client->optlen);
1142 client->optlen = length;
1143
1144 if (length > NBD_MAX_BUFFER_SIZE) {
1145 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
1146 length, NBD_MAX_BUFFER_SIZE);
1147 return -EINVAL;
1148 }
1149
1150 trace_nbd_negotiate_options_check_option(option,
1151 nbd_opt_lookup(option));
1152 if (client->tlscreds &&
1153 client->ioc == (QIOChannel *)client->sioc) {
1154 QIOChannel *tioc;
1155 if (!fixedNewstyle) {
1156 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
1157 return -EINVAL;
1158 }
1159 switch (option) {
1160 case NBD_OPT_STARTTLS:
1161 if (length) {
1162 /* Unconditionally drop the connection if the client
1163 * can't start a TLS negotiation correctly */
1164 return nbd_reject_length(client, true, errp);
1165 }
1166 tioc = nbd_negotiate_handle_starttls(client, errp);
1167 if (!tioc) {
1168 return -EIO;
1169 }
1170 ret = 0;
1171 object_unref(OBJECT(client->ioc));
1172 client->ioc = QIO_CHANNEL(tioc);
1173 break;
1174
1175 case NBD_OPT_EXPORT_NAME:
1176 /* No way to return an error to client, so drop connection */
1177 error_setg(errp, "Option 0x%x not permitted before TLS",
1178 option);
1179 return -EINVAL;
1180
1181 default:
1182 /* Let the client keep trying, unless they asked to
1183 * quit. Always try to give an error back to the
1184 * client; but when replying to OPT_ABORT, be aware
1185 * that the client may hang up before receiving the
1186 * error, in which case we are fine ignoring the
1187 * resulting EPIPE. */
1188 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD,
1189 option == NBD_OPT_ABORT ? NULL : errp,
1190 "Option 0x%" PRIx32
1191 " not permitted before TLS", option);
1192 if (option == NBD_OPT_ABORT) {
1193 return 1;
1194 }
1195 break;
1196 }
1197 } else if (fixedNewstyle) {
1198 switch (option) {
1199 case NBD_OPT_LIST:
1200 if (length) {
1201 ret = nbd_reject_length(client, false, errp);
1202 } else {
1203 ret = nbd_negotiate_handle_list(client, errp);
1204 }
1205 break;
1206
1207 case NBD_OPT_ABORT:
1208 /* NBD spec says we must try to reply before
1209 * disconnecting, but that we must also tolerate
1210 * guests that don't wait for our reply. */
1211 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL);
1212 return 1;
1213
1214 case NBD_OPT_EXPORT_NAME:
1215 return nbd_negotiate_handle_export_name(client, no_zeroes,
1216 errp);
1217
1218 case NBD_OPT_INFO:
1219 case NBD_OPT_GO:
1220 ret = nbd_negotiate_handle_info(client, errp);
1221 if (ret == 1) {
1222 assert(option == NBD_OPT_GO);
1223 return 0;
1224 }
1225 break;
1226
1227 case NBD_OPT_STARTTLS:
1228 if (length) {
1229 ret = nbd_reject_length(client, false, errp);
1230 } else if (client->tlscreds) {
1231 ret = nbd_negotiate_send_rep_err(client,
1232 NBD_REP_ERR_INVALID, errp,
1233 "TLS already enabled");
1234 } else {
1235 ret = nbd_negotiate_send_rep_err(client,
1236 NBD_REP_ERR_POLICY, errp,
1237 "TLS not configured");
1238 }
1239 break;
1240
1241 case NBD_OPT_STRUCTURED_REPLY:
1242 if (length) {
1243 ret = nbd_reject_length(client, false, errp);
1244 } else if (client->structured_reply) {
1245 ret = nbd_negotiate_send_rep_err(
1246 client, NBD_REP_ERR_INVALID, errp,
1247 "structured reply already negotiated");
1248 } else {
1249 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1250 client->structured_reply = true;
1251 }
1252 break;
1253
1254 case NBD_OPT_LIST_META_CONTEXT:
1255 case NBD_OPT_SET_META_CONTEXT:
1256 ret = nbd_negotiate_meta_queries(client, &client->export_meta,
1257 errp);
1258 break;
1259
1260 default:
1261 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,
1262 "Unsupported option %" PRIu32 " (%s)",
1263 option, nbd_opt_lookup(option));
1264 break;
1265 }
1266 } else {
1267 /*
1268 * If broken new-style we should drop the connection
1269 * for anything except NBD_OPT_EXPORT_NAME
1270 */
1271 switch (option) {
1272 case NBD_OPT_EXPORT_NAME:
1273 return nbd_negotiate_handle_export_name(client, no_zeroes,
1274 errp);
1275
1276 default:
1277 error_setg(errp, "Unsupported option %" PRIu32 " (%s)",
1278 option, nbd_opt_lookup(option));
1279 return -EINVAL;
1280 }
1281 }
1282 if (ret < 0) {
1283 return ret;
1284 }
1285 }
1286 }
1287
1288 /* nbd_negotiate
1289 * Return:
1290 * -errno on error, errp is set
1291 * 0 on successful negotiation, errp is not set
1292 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1293 * errp is not set
1294 */
1295 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
1296 {
1297 ERRP_GUARD();
1298 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
1299 int ret;
1300
1301 /* Old style negotiation header, no room for options
1302 [ 0 .. 7] passwd ("NBDMAGIC")
1303 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
1304 [16 .. 23] size
1305 [24 .. 27] export flags (zero-extended)
1306 [28 .. 151] reserved (0)
1307
1308 New style negotiation header, client can send options
1309 [ 0 .. 7] passwd ("NBDMAGIC")
1310 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
1311 [16 .. 17] server flags (0)
1312 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
1313 */
1314
1315 qio_channel_set_blocking(client->ioc, false, NULL);
1316
1317 trace_nbd_negotiate_begin();
1318 memcpy(buf, "NBDMAGIC", 8);
1319
1320 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
1321 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
1322
1323 if (nbd_write(client->ioc, buf, 18, errp) < 0) {
1324 error_prepend(errp, "write failed: ");
1325 return -EINVAL;
1326 }
1327 ret = nbd_negotiate_options(client, errp);
1328 if (ret != 0) {
1329 if (ret < 0) {
1330 error_prepend(errp, "option negotiation failed: ");
1331 }
1332 return ret;
1333 }
1334
1335 /* Attach the channel to the same AioContext as the export */
1336 if (client->exp && client->exp->ctx) {
1337 qio_channel_attach_aio_context(client->ioc, client->exp->ctx);
1338 }
1339
1340 assert(!client->optlen);
1341 trace_nbd_negotiate_success();
1342
1343 return 0;
1344 }
1345
1346 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
1347 Error **errp)
1348 {
1349 uint8_t buf[NBD_REQUEST_SIZE];
1350 uint32_t magic;
1351 int ret;
1352
1353 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp);
1354 if (ret < 0) {
1355 return ret;
1356 }
1357
1358 /* Request
1359 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
1360 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
1361 [ 6 .. 7] type (NBD_CMD_READ, ...)
1362 [ 8 .. 15] handle
1363 [16 .. 23] from
1364 [24 .. 27] len
1365 */
1366
1367 magic = ldl_be_p(buf);
1368 request->flags = lduw_be_p(buf + 4);
1369 request->type = lduw_be_p(buf + 6);
1370 request->handle = ldq_be_p(buf + 8);
1371 request->from = ldq_be_p(buf + 16);
1372 request->len = ldl_be_p(buf + 24);
1373
1374 trace_nbd_receive_request(magic, request->flags, request->type,
1375 request->from, request->len);
1376
1377 if (magic != NBD_REQUEST_MAGIC) {
1378 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
1379 return -EINVAL;
1380 }
1381 return 0;
1382 }
1383
1384 #define MAX_NBD_REQUESTS 16
1385
1386 void nbd_client_get(NBDClient *client)
1387 {
1388 client->refcount++;
1389 }
1390
1391 void nbd_client_put(NBDClient *client)
1392 {
1393 if (--client->refcount == 0) {
1394 /* The last reference should be dropped by client->close,
1395 * which is called by client_close.
1396 */
1397 assert(client->closing);
1398
1399 qio_channel_detach_aio_context(client->ioc);
1400 object_unref(OBJECT(client->sioc));
1401 object_unref(OBJECT(client->ioc));
1402 if (client->tlscreds) {
1403 object_unref(OBJECT(client->tlscreds));
1404 }
1405 g_free(client->tlsauthz);
1406 if (client->exp) {
1407 QTAILQ_REMOVE(&client->exp->clients, client, next);
1408 nbd_export_put(client->exp);
1409 }
1410 g_free(client);
1411 }
1412 }
1413
1414 static void client_close(NBDClient *client, bool negotiated)
1415 {
1416 if (client->closing) {
1417 return;
1418 }
1419
1420 client->closing = true;
1421
1422 /* Force requests to finish. They will drop their own references,
1423 * then we'll close the socket and free the NBDClient.
1424 */
1425 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
1426 NULL);
1427
1428 /* Also tell the client, so that they release their reference. */
1429 if (client->close_fn) {
1430 client->close_fn(client, negotiated);
1431 }
1432 }
1433
1434 static NBDRequestData *nbd_request_get(NBDClient *client)
1435 {
1436 NBDRequestData *req;
1437
1438 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
1439 client->nb_requests++;
1440
1441 req = g_new0(NBDRequestData, 1);
1442 nbd_client_get(client);
1443 req->client = client;
1444 return req;
1445 }
1446
1447 static void nbd_request_put(NBDRequestData *req)
1448 {
1449 NBDClient *client = req->client;
1450
1451 if (req->data) {
1452 qemu_vfree(req->data);
1453 }
1454 g_free(req);
1455
1456 client->nb_requests--;
1457 nbd_client_receive_next_request(client);
1458
1459 nbd_client_put(client);
1460 }
1461
1462 static void blk_aio_attached(AioContext *ctx, void *opaque)
1463 {
1464 NBDExport *exp = opaque;
1465 NBDClient *client;
1466
1467 trace_nbd_blk_aio_attached(exp->name, ctx);
1468
1469 exp->ctx = ctx;
1470
1471 QTAILQ_FOREACH(client, &exp->clients, next) {
1472 qio_channel_attach_aio_context(client->ioc, ctx);
1473 if (client->recv_coroutine) {
1474 aio_co_schedule(ctx, client->recv_coroutine);
1475 }
1476 if (client->send_coroutine) {
1477 aio_co_schedule(ctx, client->send_coroutine);
1478 }
1479 }
1480 }
1481
1482 static void blk_aio_detach(void *opaque)
1483 {
1484 NBDExport *exp = opaque;
1485 NBDClient *client;
1486
1487 trace_nbd_blk_aio_detach(exp->name, exp->ctx);
1488
1489 QTAILQ_FOREACH(client, &exp->clients, next) {
1490 qio_channel_detach_aio_context(client->ioc);
1491 }
1492
1493 exp->ctx = NULL;
1494 }
1495
1496 static void nbd_eject_notifier(Notifier *n, void *data)
1497 {
1498 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1499 AioContext *aio_context;
1500
1501 aio_context = exp->ctx;
1502 aio_context_acquire(aio_context);
1503 nbd_export_close(exp);
1504 aio_context_release(aio_context);
1505 }
1506
1507 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
1508 uint64_t size, const char *name, const char *desc,
1509 const char *bitmap, bool readonly, bool shared,
1510 void (*close)(NBDExport *), bool writethrough,
1511 BlockBackend *on_eject_blk, Error **errp)
1512 {
1513 AioContext *ctx;
1514 BlockBackend *blk;
1515 NBDExport *exp = g_new0(NBDExport, 1);
1516 uint64_t perm;
1517 int ret;
1518
1519 /*
1520 * NBD exports are used for non-shared storage migration. Make sure
1521 * that BDRV_O_INACTIVE is cleared and the image is ready for write
1522 * access since the export could be available before migration handover.
1523 * ctx was acquired in the caller.
1524 */
1525 assert(name && strlen(name) <= NBD_MAX_STRING_SIZE);
1526 ctx = bdrv_get_aio_context(bs);
1527 bdrv_invalidate_cache(bs, NULL);
1528
1529 /* Don't allow resize while the NBD server is running, otherwise we don't
1530 * care what happens with the node. */
1531 perm = BLK_PERM_CONSISTENT_READ;
1532 if (!readonly) {
1533 perm |= BLK_PERM_WRITE;
1534 }
1535 blk = blk_new(ctx, perm,
1536 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1537 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
1538 ret = blk_insert_bs(blk, bs, errp);
1539 if (ret < 0) {
1540 goto fail;
1541 }
1542 blk_set_enable_write_cache(blk, !writethrough);
1543 blk_set_allow_aio_context_change(blk, true);
1544
1545 exp->refcount = 1;
1546 QTAILQ_INIT(&exp->clients);
1547 exp->blk = blk;
1548 assert(dev_offset <= INT64_MAX);
1549 exp->dev_offset = dev_offset;
1550 exp->name = g_strdup(name);
1551 assert(!desc || strlen(desc) <= NBD_MAX_STRING_SIZE);
1552 exp->description = g_strdup(desc);
1553 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH |
1554 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE);
1555 if (readonly) {
1556 exp->nbdflags |= NBD_FLAG_READ_ONLY;
1557 if (shared) {
1558 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
1559 }
1560 } else {
1561 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES |
1562 NBD_FLAG_SEND_FAST_ZERO);
1563 }
1564 assert(size <= INT64_MAX - dev_offset);
1565 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
1566
1567 if (bitmap) {
1568 BdrvDirtyBitmap *bm = NULL;
1569
1570 while (bs) {
1571 bm = bdrv_find_dirty_bitmap(bs, bitmap);
1572 if (bm != NULL) {
1573 break;
1574 }
1575
1576 bs = bdrv_filter_or_cow_bs(bs);
1577 }
1578
1579 if (bm == NULL) {
1580 error_setg(errp, "Bitmap '%s' is not found", bitmap);
1581 goto fail;
1582 }
1583
1584 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
1585 goto fail;
1586 }
1587
1588 if (readonly && bdrv_is_writable(bs) &&
1589 bdrv_dirty_bitmap_enabled(bm)) {
1590 error_setg(errp,
1591 "Enabled bitmap '%s' incompatible with readonly export",
1592 bitmap);
1593 goto fail;
1594 }
1595
1596 bdrv_dirty_bitmap_set_busy(bm, true);
1597 exp->export_bitmap = bm;
1598 assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE);
1599 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s",
1600 bitmap);
1601 assert(strlen(exp->export_bitmap_context) < NBD_MAX_STRING_SIZE);
1602 }
1603
1604 exp->close = close;
1605 exp->ctx = ctx;
1606 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1607
1608 if (on_eject_blk) {
1609 blk_ref(on_eject_blk);
1610 exp->eject_notifier_blk = on_eject_blk;
1611 exp->eject_notifier.notify = nbd_eject_notifier;
1612 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1613 }
1614 QTAILQ_INSERT_TAIL(&exports, exp, next);
1615 nbd_export_get(exp);
1616 return exp;
1617
1618 fail:
1619 blk_unref(blk);
1620 g_free(exp->name);
1621 g_free(exp->description);
1622 g_free(exp);
1623 return NULL;
1624 }
1625
1626 NBDExport *nbd_export_find(const char *name)
1627 {
1628 NBDExport *exp;
1629 QTAILQ_FOREACH(exp, &exports, next) {
1630 if (strcmp(name, exp->name) == 0) {
1631 return exp;
1632 }
1633 }
1634
1635 return NULL;
1636 }
1637
1638 AioContext *
1639 nbd_export_aio_context(NBDExport *exp)
1640 {
1641 return exp->ctx;
1642 }
1643
1644 void nbd_export_close(NBDExport *exp)
1645 {
1646 NBDClient *client, *next;
1647
1648 nbd_export_get(exp);
1649 /*
1650 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a
1651 * close mode that stops advertising the export to new clients but
1652 * still permits existing clients to run to completion? Because of
1653 * that possibility, nbd_export_close() can be called more than
1654 * once on an export.
1655 */
1656 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1657 client_close(client, true);
1658 }
1659 if (exp->name) {
1660 nbd_export_put(exp);
1661 g_free(exp->name);
1662 exp->name = NULL;
1663 QTAILQ_REMOVE(&exports, exp, next);
1664 QTAILQ_INSERT_TAIL(&closed_exports, exp, next);
1665 }
1666 g_free(exp->description);
1667 exp->description = NULL;
1668 nbd_export_put(exp);
1669 }
1670
1671 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
1672 {
1673 ERRP_GUARD();
1674 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
1675 nbd_export_close(exp);
1676 return;
1677 }
1678
1679 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE);
1680
1681 error_setg(errp, "export '%s' still in use", exp->name);
1682 error_append_hint(errp, "Use mode='hard' to force client disconnect\n");
1683 }
1684
1685 void nbd_export_get(NBDExport *exp)
1686 {
1687 assert(exp->refcount > 0);
1688 exp->refcount++;
1689 }
1690
1691 void nbd_export_put(NBDExport *exp)
1692 {
1693 assert(exp->refcount > 0);
1694 if (exp->refcount == 1) {
1695 nbd_export_close(exp);
1696 }
1697
1698 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen
1699 * if someone calls nbd_export_put() on named export not through
1700 * nbd_export_set_name() when refcount is 1. So, let's assert that
1701 * it is > 0.
1702 */
1703 assert(exp->refcount > 0);
1704 if (--exp->refcount == 0) {
1705 assert(exp->name == NULL);
1706 assert(exp->description == NULL);
1707
1708 if (exp->close) {
1709 exp->close(exp);
1710 }
1711
1712 if (exp->blk) {
1713 if (exp->eject_notifier_blk) {
1714 notifier_remove(&exp->eject_notifier);
1715 blk_unref(exp->eject_notifier_blk);
1716 }
1717 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1718 blk_aio_detach, exp);
1719 blk_unref(exp->blk);
1720 exp->blk = NULL;
1721 }
1722
1723 if (exp->export_bitmap) {
1724 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false);
1725 g_free(exp->export_bitmap_context);
1726 }
1727
1728 QTAILQ_REMOVE(&closed_exports, exp, next);
1729 g_free(exp);
1730 aio_wait_kick();
1731 }
1732 }
1733
1734 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1735 {
1736 return exp->blk;
1737 }
1738
1739 void nbd_export_close_all(void)
1740 {
1741 NBDExport *exp, *next;
1742 AioContext *aio_context;
1743
1744 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1745 aio_context = exp->ctx;
1746 aio_context_acquire(aio_context);
1747 nbd_export_close(exp);
1748 aio_context_release(aio_context);
1749 }
1750
1751 AIO_WAIT_WHILE(NULL, !(QTAILQ_EMPTY(&exports) &&
1752 QTAILQ_EMPTY(&closed_exports)));
1753 }
1754
1755 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
1756 unsigned niov, Error **errp)
1757 {
1758 int ret;
1759
1760 g_assert(qemu_in_coroutine());
1761 qemu_co_mutex_lock(&client->send_lock);
1762 client->send_coroutine = qemu_coroutine_self();
1763
1764 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
1765
1766 client->send_coroutine = NULL;
1767 qemu_co_mutex_unlock(&client->send_lock);
1768
1769 return ret;
1770 }
1771
1772 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
1773 uint64_t handle)
1774 {
1775 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
1776 stl_be_p(&reply->error, error);
1777 stq_be_p(&reply->handle, handle);
1778 }
1779
1780 static int nbd_co_send_simple_reply(NBDClient *client,
1781 uint64_t handle,
1782 uint32_t error,
1783 void *data,
1784 size_t len,
1785 Error **errp)
1786 {
1787 NBDSimpleReply reply;
1788 int nbd_err = system_errno_to_nbd_errno(error);
1789 struct iovec iov[] = {
1790 {.iov_base = &reply, .iov_len = sizeof(reply)},
1791 {.iov_base = data, .iov_len = len}
1792 };
1793
1794 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
1795 len);
1796 set_be_simple_reply(&reply, nbd_err, handle);
1797
1798 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
1799 }
1800
1801 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,
1802 uint16_t type, uint64_t handle, uint32_t length)
1803 {
1804 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
1805 stw_be_p(&chunk->flags, flags);
1806 stw_be_p(&chunk->type, type);
1807 stq_be_p(&chunk->handle, handle);
1808 stl_be_p(&chunk->length, length);
1809 }
1810
1811 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,
1812 uint64_t handle,
1813 Error **errp)
1814 {
1815 NBDStructuredReplyChunk chunk;
1816 struct iovec iov[] = {
1817 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1818 };
1819
1820 trace_nbd_co_send_structured_done(handle);
1821 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);
1822
1823 return nbd_co_send_iov(client, iov, 1, errp);
1824 }
1825
1826 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,
1827 uint64_t handle,
1828 uint64_t offset,
1829 void *data,
1830 size_t size,
1831 bool final,
1832 Error **errp)
1833 {
1834 NBDStructuredReadData chunk;
1835 struct iovec iov[] = {
1836 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1837 {.iov_base = data, .iov_len = size}
1838 };
1839
1840 assert(size);
1841 trace_nbd_co_send_structured_read(handle, offset, data, size);
1842 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1843 NBD_REPLY_TYPE_OFFSET_DATA, handle,
1844 sizeof(chunk) - sizeof(chunk.h) + size);
1845 stq_be_p(&chunk.offset, offset);
1846
1847 return nbd_co_send_iov(client, iov, 2, errp);
1848 }
1849
1850 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
1851 uint64_t handle,
1852 uint32_t error,
1853 const char *msg,
1854 Error **errp)
1855 {
1856 NBDStructuredError chunk;
1857 int nbd_err = system_errno_to_nbd_errno(error);
1858 struct iovec iov[] = {
1859 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1860 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
1861 };
1862
1863 assert(nbd_err);
1864 trace_nbd_co_send_structured_error(handle, nbd_err,
1865 nbd_err_lookup(nbd_err), msg ? msg : "");
1866 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,
1867 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1868 stl_be_p(&chunk.error, nbd_err);
1869 stw_be_p(&chunk.message_length, iov[1].iov_len);
1870
1871 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);
1872 }
1873
1874 /* Do a sparse read and send the structured reply to the client.
1875 * Returns -errno if sending fails. bdrv_block_status_above() failure is
1876 * reported to the client, at which point this function succeeds.
1877 */
1878 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
1879 uint64_t handle,
1880 uint64_t offset,
1881 uint8_t *data,
1882 size_t size,
1883 Error **errp)
1884 {
1885 int ret = 0;
1886 NBDExport *exp = client->exp;
1887 size_t progress = 0;
1888
1889 while (progress < size) {
1890 int64_t pnum;
1891 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL,
1892 offset + progress,
1893 size - progress, &pnum, NULL,
1894 NULL);
1895 bool final;
1896
1897 if (status < 0) {
1898 char *msg = g_strdup_printf("unable to check for holes: %s",
1899 strerror(-status));
1900
1901 ret = nbd_co_send_structured_error(client, handle, -status, msg,
1902 errp);
1903 g_free(msg);
1904 return ret;
1905 }
1906 assert(pnum && pnum <= size - progress);
1907 final = progress + pnum == size;
1908 if (status & BDRV_BLOCK_ZERO) {
1909 NBDStructuredReadHole chunk;
1910 struct iovec iov[] = {
1911 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1912 };
1913
1914 trace_nbd_co_send_structured_read_hole(handle, offset + progress,
1915 pnum);
1916 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1917 NBD_REPLY_TYPE_OFFSET_HOLE,
1918 handle, sizeof(chunk) - sizeof(chunk.h));
1919 stq_be_p(&chunk.offset, offset + progress);
1920 stl_be_p(&chunk.length, pnum);
1921 ret = nbd_co_send_iov(client, iov, 1, errp);
1922 } else {
1923 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset,
1924 data + progress, pnum);
1925 if (ret < 0) {
1926 error_setg_errno(errp, -ret, "reading from file failed");
1927 break;
1928 }
1929 ret = nbd_co_send_structured_read(client, handle, offset + progress,
1930 data + progress, pnum, final,
1931 errp);
1932 }
1933
1934 if (ret < 0) {
1935 break;
1936 }
1937 progress += pnum;
1938 }
1939 return ret;
1940 }
1941
1942 typedef struct NBDExtentArray {
1943 NBDExtent *extents;
1944 unsigned int nb_alloc;
1945 unsigned int count;
1946 uint64_t total_length;
1947 bool can_add;
1948 bool converted_to_be;
1949 } NBDExtentArray;
1950
1951 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc)
1952 {
1953 NBDExtentArray *ea = g_new0(NBDExtentArray, 1);
1954
1955 ea->nb_alloc = nb_alloc;
1956 ea->extents = g_new(NBDExtent, nb_alloc);
1957 ea->can_add = true;
1958
1959 return ea;
1960 }
1961
1962 static void nbd_extent_array_free(NBDExtentArray *ea)
1963 {
1964 g_free(ea->extents);
1965 g_free(ea);
1966 }
1967 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free);
1968
1969 /* Further modifications of the array after conversion are abandoned */
1970 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea)
1971 {
1972 int i;
1973
1974 assert(!ea->converted_to_be);
1975 ea->can_add = false;
1976 ea->converted_to_be = true;
1977
1978 for (i = 0; i < ea->count; i++) {
1979 ea->extents[i].flags = cpu_to_be32(ea->extents[i].flags);
1980 ea->extents[i].length = cpu_to_be32(ea->extents[i].length);
1981 }
1982 }
1983
1984 /*
1985 * Add extent to NBDExtentArray. If extent can't be added (no available space),
1986 * return -1.
1987 * For safety, when returning -1 for the first time, .can_add is set to false,
1988 * further call to nbd_extent_array_add() will crash.
1989 * (to avoid the situation, when after failing to add an extent (returned -1),
1990 * user miss this failure and add another extent, which is successfully added
1991 * (array is full, but new extent may be squashed into the last one), then we
1992 * have invalid array with skipped extent)
1993 */
1994 static int nbd_extent_array_add(NBDExtentArray *ea,
1995 uint32_t length, uint32_t flags)
1996 {
1997 assert(ea->can_add);
1998
1999 if (!length) {
2000 return 0;
2001 }
2002
2003 /* Extend previous extent if flags are the same */
2004 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) {
2005 uint64_t sum = (uint64_t)length + ea->extents[ea->count - 1].length;
2006
2007 if (sum <= UINT32_MAX) {
2008 ea->extents[ea->count - 1].length = sum;
2009 ea->total_length += length;
2010 return 0;
2011 }
2012 }
2013
2014 if (ea->count >= ea->nb_alloc) {
2015 ea->can_add = false;
2016 return -1;
2017 }
2018
2019 ea->total_length += length;
2020 ea->extents[ea->count] = (NBDExtent) {.length = length, .flags = flags};
2021 ea->count++;
2022
2023 return 0;
2024 }
2025
2026 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
2027 uint64_t bytes, NBDExtentArray *ea)
2028 {
2029 while (bytes) {
2030 uint32_t flags;
2031 int64_t num;
2032 int ret = bdrv_block_status_above(bs, NULL, offset, bytes, &num,
2033 NULL, NULL);
2034
2035 if (ret < 0) {
2036 return ret;
2037 }
2038
2039 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |
2040 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
2041
2042 if (nbd_extent_array_add(ea, num, flags) < 0) {
2043 return 0;
2044 }
2045
2046 offset += num;
2047 bytes -= num;
2048 }
2049
2050 return 0;
2051 }
2052
2053 /*
2054 * nbd_co_send_extents
2055 *
2056 * @ea is converted to BE by the function
2057 * @last controls whether NBD_REPLY_FLAG_DONE is sent.
2058 */
2059 static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
2060 NBDExtentArray *ea,
2061 bool last, uint32_t context_id, Error **errp)
2062 {
2063 NBDStructuredMeta chunk;
2064 struct iovec iov[] = {
2065 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
2066 {.iov_base = ea->extents, .iov_len = ea->count * sizeof(ea->extents[0])}
2067 };
2068
2069 nbd_extent_array_convert_to_be(ea);
2070
2071 trace_nbd_co_send_extents(handle, ea->count, context_id, ea->total_length,
2072 last);
2073 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0,
2074 NBD_REPLY_TYPE_BLOCK_STATUS,
2075 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
2076 stl_be_p(&chunk.context_id, context_id);
2077
2078 return nbd_co_send_iov(client, iov, 2, errp);
2079 }
2080
2081 /* Get block status from the exported device and send it to the client */
2082 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
2083 BlockDriverState *bs, uint64_t offset,
2084 uint32_t length, bool dont_fragment,
2085 bool last, uint32_t context_id,
2086 Error **errp)
2087 {
2088 int ret;
2089 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
2090 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
2091
2092 ret = blockstatus_to_extents(bs, offset, length, ea);
2093 if (ret < 0) {
2094 return nbd_co_send_structured_error(
2095 client, handle, -ret, "can't get block status", errp);
2096 }
2097
2098 return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
2099 }
2100
2101 /* Populate @ea from a dirty bitmap. */
2102 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap,
2103 uint64_t offset, uint64_t length,
2104 NBDExtentArray *es)
2105 {
2106 int64_t start, dirty_start, dirty_count;
2107 int64_t end = offset + length;
2108 bool full = false;
2109
2110 bdrv_dirty_bitmap_lock(bitmap);
2111
2112 for (start = offset;
2113 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX,
2114 &dirty_start, &dirty_count);
2115 start = dirty_start + dirty_count)
2116 {
2117 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) ||
2118 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0))
2119 {
2120 full = true;
2121 break;
2122 }
2123 }
2124
2125 if (!full) {
2126 /* last non dirty extent */
2127 nbd_extent_array_add(es, end - start, 0);
2128 }
2129
2130 bdrv_dirty_bitmap_unlock(bitmap);
2131 }
2132
2133 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
2134 BdrvDirtyBitmap *bitmap, uint64_t offset,
2135 uint32_t length, bool dont_fragment, bool last,
2136 uint32_t context_id, Error **errp)
2137 {
2138 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
2139 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
2140
2141 bitmap_to_extents(bitmap, offset, length, ea);
2142
2143 return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
2144 }
2145
2146 /* nbd_co_receive_request
2147 * Collect a client request. Return 0 if request looks valid, -EIO to drop
2148 * connection right away, and any other negative value to report an error to
2149 * the client (although the caller may still need to disconnect after reporting
2150 * the error).
2151 */
2152 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
2153 Error **errp)
2154 {
2155 NBDClient *client = req->client;
2156 int valid_flags;
2157
2158 g_assert(qemu_in_coroutine());
2159 assert(client->recv_coroutine == qemu_coroutine_self());
2160 if (nbd_receive_request(client->ioc, request, errp) < 0) {
2161 return -EIO;
2162 }
2163
2164 trace_nbd_co_receive_request_decode_type(request->handle, request->type,
2165 nbd_cmd_lookup(request->type));
2166
2167 if (request->type != NBD_CMD_WRITE) {
2168 /* No payload, we are ready to read the next request. */
2169 req->complete = true;
2170 }
2171
2172 if (request->type == NBD_CMD_DISC) {
2173 /* Special case: we're going to disconnect without a reply,
2174 * whether or not flags, from, or len are bogus */
2175 return -EIO;
2176 }
2177
2178 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE ||
2179 request->type == NBD_CMD_CACHE)
2180 {
2181 if (request->len > NBD_MAX_BUFFER_SIZE) {
2182 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
2183 request->len, NBD_MAX_BUFFER_SIZE);
2184 return -EINVAL;
2185 }
2186
2187 if (request->type != NBD_CMD_CACHE) {
2188 req->data = blk_try_blockalign(client->exp->blk, request->len);
2189 if (req->data == NULL) {
2190 error_setg(errp, "No memory");
2191 return -ENOMEM;
2192 }
2193 }
2194 }
2195
2196 if (request->type == NBD_CMD_WRITE) {
2197 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data",
2198 errp) < 0)
2199 {
2200 return -EIO;
2201 }
2202 req->complete = true;
2203
2204 trace_nbd_co_receive_request_payload_received(request->handle,
2205 request->len);
2206 }
2207
2208 /* Sanity checks. */
2209 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY &&
2210 (request->type == NBD_CMD_WRITE ||
2211 request->type == NBD_CMD_WRITE_ZEROES ||
2212 request->type == NBD_CMD_TRIM)) {
2213 error_setg(errp, "Export is read-only");
2214 return -EROFS;
2215 }
2216 if (request->from > client->exp->size ||
2217 request->len > client->exp->size - request->from) {
2218 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
2219 ", Size: %" PRIu64, request->from, request->len,
2220 client->exp->size);
2221 return (request->type == NBD_CMD_WRITE ||
2222 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
2223 }
2224 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len,
2225 client->check_align)) {
2226 /*
2227 * The block layer gracefully handles unaligned requests, but
2228 * it's still worth tracing client non-compliance
2229 */
2230 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type),
2231 request->from,
2232 request->len,
2233 client->check_align);
2234 }
2235 valid_flags = NBD_CMD_FLAG_FUA;
2236 if (request->type == NBD_CMD_READ && client->structured_reply) {
2237 valid_flags |= NBD_CMD_FLAG_DF;
2238 } else if (request->type == NBD_CMD_WRITE_ZEROES) {
2239 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO;
2240 } else if (request->type == NBD_CMD_BLOCK_STATUS) {
2241 valid_flags |= NBD_CMD_FLAG_REQ_ONE;
2242 }
2243 if (request->flags & ~valid_flags) {
2244 error_setg(errp, "unsupported flags for command %s (got 0x%x)",
2245 nbd_cmd_lookup(request->type), request->flags);
2246 return -EINVAL;
2247 }
2248
2249 return 0;
2250 }
2251
2252 /* Send simple reply without a payload, or a structured error
2253 * @error_msg is ignored if @ret >= 0
2254 * Returns 0 if connection is still live, -errno on failure to talk to client
2255 */
2256 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
2257 uint64_t handle,
2258 int ret,
2259 const char *error_msg,
2260 Error **errp)
2261 {
2262 if (client->structured_reply && ret < 0) {
2263 return nbd_co_send_structured_error(client, handle, -ret, error_msg,
2264 errp);
2265 } else {
2266 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,
2267 NULL, 0, errp);
2268 }
2269 }
2270
2271 /* Handle NBD_CMD_READ request.
2272 * Return -errno if sending fails. Other errors are reported directly to the
2273 * client as an error reply. */
2274 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
2275 uint8_t *data, Error **errp)
2276 {
2277 int ret;
2278 NBDExport *exp = client->exp;
2279
2280 assert(request->type == NBD_CMD_READ);
2281
2282 /* XXX: NBD Protocol only documents use of FUA with WRITE */
2283 if (request->flags & NBD_CMD_FLAG_FUA) {
2284 ret = blk_co_flush(exp->blk);
2285 if (ret < 0) {
2286 return nbd_send_generic_reply(client, request->handle, ret,
2287 "flush failed", errp);
2288 }
2289 }
2290
2291 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&
2292 request->len)
2293 {
2294 return nbd_co_send_sparse_read(client, request->handle, request->from,
2295 data, request->len, errp);
2296 }
2297
2298 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data,
2299 request->len);
2300 if (ret < 0) {
2301 return nbd_send_generic_reply(client, request->handle, ret,
2302 "reading from file failed", errp);
2303 }
2304
2305 if (client->structured_reply) {
2306 if (request->len) {
2307 return nbd_co_send_structured_read(client, request->handle,
2308 request->from, data,
2309 request->len, true, errp);
2310 } else {
2311 return nbd_co_send_structured_done(client, request->handle, errp);
2312 }
2313 } else {
2314 return nbd_co_send_simple_reply(client, request->handle, 0,
2315 data, request->len, errp);
2316 }
2317 }
2318
2319 /*
2320 * nbd_do_cmd_cache
2321 *
2322 * Handle NBD_CMD_CACHE request.
2323 * Return -errno if sending fails. Other errors are reported directly to the
2324 * client as an error reply.
2325 */
2326 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request,
2327 Error **errp)
2328 {
2329 int ret;
2330 NBDExport *exp = client->exp;
2331
2332 assert(request->type == NBD_CMD_CACHE);
2333
2334 ret = blk_co_preadv(exp->blk, request->from + exp->dev_offset, request->len,
2335 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH);
2336
2337 return nbd_send_generic_reply(client, request->handle, ret,
2338 "caching data failed", errp);
2339 }
2340
2341 /* Handle NBD request.
2342 * Return -errno if sending fails. Other errors are reported directly to the
2343 * client as an error reply. */
2344 static coroutine_fn int nbd_handle_request(NBDClient *client,
2345 NBDRequest *request,
2346 uint8_t *data, Error **errp)
2347 {
2348 int ret;
2349 int flags;
2350 NBDExport *exp = client->exp;
2351 char *msg;
2352
2353 switch (request->type) {
2354 case NBD_CMD_CACHE:
2355 return nbd_do_cmd_cache(client, request, errp);
2356
2357 case NBD_CMD_READ:
2358 return nbd_do_cmd_read(client, request, data, errp);
2359
2360 case NBD_CMD_WRITE:
2361 flags = 0;
2362 if (request->flags & NBD_CMD_FLAG_FUA) {
2363 flags |= BDRV_REQ_FUA;
2364 }
2365 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset,
2366 data, request->len, flags);
2367 return nbd_send_generic_reply(client, request->handle, ret,
2368 "writing to file failed", errp);
2369
2370 case NBD_CMD_WRITE_ZEROES:
2371 flags = 0;
2372 if (request->flags & NBD_CMD_FLAG_FUA) {
2373 flags |= BDRV_REQ_FUA;
2374 }
2375 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) {
2376 flags |= BDRV_REQ_MAY_UNMAP;
2377 }
2378 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) {
2379 flags |= BDRV_REQ_NO_FALLBACK;
2380 }
2381 ret = 0;
2382 /* FIXME simplify this when blk_pwrite_zeroes switches to 64-bit */
2383 while (ret >= 0 && request->len) {
2384 int align = client->check_align ?: 1;
2385 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES,
2386 align));
2387 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset,
2388 len, flags);
2389 request->len -= len;
2390 request->from += len;
2391 }
2392 return nbd_send_generic_reply(client, request->handle, ret,
2393 "writing to file failed", errp);
2394
2395 case NBD_CMD_DISC:
2396 /* unreachable, thanks to special case in nbd_co_receive_request() */
2397 abort();
2398
2399 case NBD_CMD_FLUSH:
2400 ret = blk_co_flush(exp->blk);
2401 return nbd_send_generic_reply(client, request->handle, ret,
2402 "flush failed", errp);
2403
2404 case NBD_CMD_TRIM:
2405 ret = 0;
2406 /* FIXME simplify this when blk_co_pdiscard switches to 64-bit */
2407 while (ret >= 0 && request->len) {
2408 int align = client->check_align ?: 1;
2409 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES,
2410 align));
2411 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset,
2412 len);
2413 request->len -= len;
2414 request->from += len;
2415 }
2416 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) {
2417 ret = blk_co_flush(exp->blk);
2418 }
2419 return nbd_send_generic_reply(client, request->handle, ret,
2420 "discard failed", errp);
2421
2422 case NBD_CMD_BLOCK_STATUS:
2423 if (!request->len) {
2424 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2425 "need non-zero length", errp);
2426 }
2427 if (client->export_meta.valid &&
2428 (client->export_meta.base_allocation ||
2429 client->export_meta.bitmap))
2430 {
2431 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
2432
2433 if (client->export_meta.base_allocation) {
2434 ret = nbd_co_send_block_status(client, request->handle,
2435 blk_bs(exp->blk), request->from,
2436 request->len, dont_fragment,
2437 !client->export_meta.bitmap,
2438 NBD_META_ID_BASE_ALLOCATION,
2439 errp);
2440 if (ret < 0) {
2441 return ret;
2442 }
2443 }
2444
2445 if (client->export_meta.bitmap) {
2446 ret = nbd_co_send_bitmap(client, request->handle,
2447 client->exp->export_bitmap,
2448 request->from, request->len,
2449 dont_fragment,
2450 true, NBD_META_ID_DIRTY_BITMAP, errp);
2451 if (ret < 0) {
2452 return ret;
2453 }
2454 }
2455
2456 return 0;
2457 } else {
2458 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2459 "CMD_BLOCK_STATUS not negotiated",
2460 errp);
2461 }
2462
2463 default:
2464 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
2465 request->type);
2466 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,
2467 errp);
2468 g_free(msg);
2469 return ret;
2470 }
2471 }
2472
2473 /* Owns a reference to the NBDClient passed as opaque. */
2474 static coroutine_fn void nbd_trip(void *opaque)
2475 {
2476 NBDClient *client = opaque;
2477 NBDRequestData *req;
2478 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
2479 int ret;
2480 Error *local_err = NULL;
2481
2482 trace_nbd_trip();
2483 if (client->closing) {
2484 nbd_client_put(client);
2485 return;
2486 }
2487
2488 req = nbd_request_get(client);
2489 ret = nbd_co_receive_request(req, &request, &local_err);
2490 client->recv_coroutine = NULL;
2491
2492 if (client->closing) {
2493 /*
2494 * The client may be closed when we are blocked in
2495 * nbd_co_receive_request()
2496 */
2497 goto done;
2498 }
2499
2500 nbd_client_receive_next_request(client);
2501 if (ret == -EIO) {
2502 goto disconnect;
2503 }
2504
2505 if (ret < 0) {
2506 /* It wans't -EIO, so, according to nbd_co_receive_request()
2507 * semantics, we should return the error to the client. */
2508 Error *export_err = local_err;
2509
2510 local_err = NULL;
2511 ret = nbd_send_generic_reply(client, request.handle, -EINVAL,
2512 error_get_pretty(export_err), &local_err);
2513 error_free(export_err);
2514 } else {
2515 ret = nbd_handle_request(client, &request, req->data, &local_err);
2516 }
2517 if (ret < 0) {
2518 error_prepend(&local_err, "Failed to send reply: ");
2519 goto disconnect;
2520 }
2521
2522 /* We must disconnect after NBD_CMD_WRITE if we did not
2523 * read the payload.
2524 */
2525 if (!req->complete) {
2526 error_setg(&local_err, "Request handling failed in intermediate state");
2527 goto disconnect;
2528 }
2529
2530 done:
2531 nbd_request_put(req);
2532 nbd_client_put(client);
2533 return;
2534
2535 disconnect:
2536 if (local_err) {
2537 error_reportf_err(local_err, "Disconnect client, due to: ");
2538 }
2539 nbd_request_put(req);
2540 client_close(client, true);
2541 nbd_client_put(client);
2542 }
2543
2544 static void nbd_client_receive_next_request(NBDClient *client)
2545 {
2546 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
2547 nbd_client_get(client);
2548 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
2549 aio_co_schedule(client->exp->ctx, client->recv_coroutine);
2550 }
2551 }
2552
2553 static coroutine_fn void nbd_co_client_start(void *opaque)
2554 {
2555 NBDClient *client = opaque;
2556 Error *local_err = NULL;
2557
2558 qemu_co_mutex_init(&client->send_lock);
2559
2560 if (nbd_negotiate(client, &local_err)) {
2561 if (local_err) {
2562 error_report_err(local_err);
2563 }
2564 client_close(client, false);
2565 return;
2566 }
2567
2568 nbd_client_receive_next_request(client);
2569 }
2570
2571 /*
2572 * Create a new client listener using the given channel @sioc.
2573 * Begin servicing it in a coroutine. When the connection closes, call
2574 * @close_fn with an indication of whether the client completed negotiation.
2575 */
2576 void nbd_client_new(QIOChannelSocket *sioc,
2577 QCryptoTLSCreds *tlscreds,
2578 const char *tlsauthz,
2579 void (*close_fn)(NBDClient *, bool))
2580 {
2581 NBDClient *client;
2582 Coroutine *co;
2583
2584 client = g_new0(NBDClient, 1);
2585 client->refcount = 1;
2586 client->tlscreds = tlscreds;
2587 if (tlscreds) {
2588 object_ref(OBJECT(client->tlscreds));
2589 }
2590 client->tlsauthz = g_strdup(tlsauthz);
2591 client->sioc = sioc;
2592 object_ref(OBJECT(client->sioc));
2593 client->ioc = QIO_CHANNEL(sioc);
2594 object_ref(OBJECT(client->ioc));
2595 client->close_fn = close_fn;
2596
2597 co = qemu_coroutine_create(nbd_co_client_start, client);
2598 qemu_coroutine_enter(co);
2599 }
QEmu