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nbd/server: Prepare to send extended header replies
[qemu/kevin.git] / nbd / server.c
blob910c48c64672184225b224a605bd33b0c1b80340
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 /* 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 size_t count; /* number of negotiated contexts */
114 bool base_allocation; /* export base:allocation context (block status) */
115 bool allocation_depth; /* export qemu:allocation-depth */
116 bool *bitmaps; /*
117 * export qemu:dirty-bitmap:<export bitmap name>,
118 * sized by exp->nr_export_bitmaps
119 */
120 } NBDExportMetaContexts;
121
122 struct NBDClient {
123 int refcount;
124 void (*close_fn)(NBDClient *client, bool negotiated);
125
126 NBDExport *exp;
127 QCryptoTLSCreds *tlscreds;
128 char *tlsauthz;
129 QIOChannelSocket *sioc; /* The underlying data channel */
130 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
131
132 Coroutine *recv_coroutine;
133
134 CoMutex send_lock;
135 Coroutine *send_coroutine;
136
137 bool read_yielding;
138 bool quiescing;
139
140 QTAILQ_ENTRY(NBDClient) next;
141 int nb_requests;
142 bool closing;
143
144 uint32_t check_align; /* If non-zero, check for aligned client requests */
145
146 NBDMode mode;
147 NBDExportMetaContexts export_meta;
148
149 uint32_t opt; /* Current option being negotiated */
150 uint32_t optlen; /* remaining length of data in ioc for the option being
151 negotiated now */
152 };
153
154 static void nbd_client_receive_next_request(NBDClient *client);
155
156 /* Basic flow for negotiation
157
158 Server Client
159 Negotiate
160
161 or
162
163 Server Client
164 Negotiate #1
165 Option
166 Negotiate #2
167
168 ----
169
170 followed by
171
172 Server Client
173 Request
174 Response
175 Request
176 Response
177 ...
178 ...
179 Request (type == 2)
180
181 */
182
183 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
184 uint32_t type, uint32_t length)
185 {
186 stq_be_p(&rep->magic, NBD_REP_MAGIC);
187 stl_be_p(&rep->option, option);
188 stl_be_p(&rep->type, type);
189 stl_be_p(&rep->length, length);
190 }
191
192 /* Send a reply header, including length, but no payload.
193 * Return -errno on error, 0 on success. */
194 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
195 uint32_t len, Error **errp)
196 {
197 NBDOptionReply rep;
198
199 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),
200 type, nbd_rep_lookup(type), len);
201
202 assert(len < NBD_MAX_BUFFER_SIZE);
203
204 set_be_option_rep(&rep, client->opt, type, len);
205 return nbd_write(client->ioc, &rep, sizeof(rep), errp);
206 }
207
208 /* Send a reply header with default 0 length.
209 * Return -errno on error, 0 on success. */
210 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
211 Error **errp)
212 {
213 return nbd_negotiate_send_rep_len(client, type, 0, errp);
214 }
215
216 /* Send an error reply.
217 * Return -errno on error, 0 on success. */
218 static int G_GNUC_PRINTF(4, 0)
219 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
220 Error **errp, const char *fmt, va_list va)
221 {
222 ERRP_GUARD();
223 g_autofree char *msg = NULL;
224 int ret;
225 size_t len;
226
227 msg = g_strdup_vprintf(fmt, va);
228 len = strlen(msg);
229 assert(len < NBD_MAX_STRING_SIZE);
230 trace_nbd_negotiate_send_rep_err(msg);
231 ret = nbd_negotiate_send_rep_len(client, type, len, errp);
232 if (ret < 0) {
233 return ret;
234 }
235 if (nbd_write(client->ioc, msg, len, errp) < 0) {
236 error_prepend(errp, "write failed (error message): ");
237 return -EIO;
238 }
239
240 return 0;
241 }
242
243 /*
244 * Return a malloc'd copy of @name suitable for use in an error reply.
245 */
246 static char *
247 nbd_sanitize_name(const char *name)
248 {
249 if (strnlen(name, 80) < 80) {
250 return g_strdup(name);
251 }
252 /* XXX Should we also try to sanitize any control characters? */
253 return g_strdup_printf("%.80s...", name);
254 }
255
256 /* Send an error reply.
257 * Return -errno on error, 0 on success. */
258 static int G_GNUC_PRINTF(4, 5)
259 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
260 Error **errp, const char *fmt, ...)
261 {
262 va_list va;
263 int ret;
264
265 va_start(va, fmt);
266 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
267 va_end(va);
268 return ret;
269 }
270
271 /* Drop remainder of the current option, and send a reply with the
272 * given error type and message. Return -errno on read or write
273 * failure; or 0 if connection is still live. */
274 static int G_GNUC_PRINTF(4, 0)
275 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
276 const char *fmt, va_list va)
277 {
278 int ret = nbd_drop(client->ioc, client->optlen, errp);
279
280 client->optlen = 0;
281 if (!ret) {
282 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
283 }
284 return ret;
285 }
286
287 static int G_GNUC_PRINTF(4, 5)
288 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
289 const char *fmt, ...)
290 {
291 int ret;
292 va_list va;
293
294 va_start(va, fmt);
295 ret = nbd_opt_vdrop(client, type, errp, fmt, va);
296 va_end(va);
297
298 return ret;
299 }
300
301 static int G_GNUC_PRINTF(3, 4)
302 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
303 {
304 int ret;
305 va_list va;
306
307 va_start(va, fmt);
308 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);
309 va_end(va);
310
311 return ret;
312 }
313
314 /* Read size bytes from the unparsed payload of the current option.
315 * If @check_nul, require that no NUL bytes appear in buffer.
316 * Return -errno on I/O error, 0 if option was completely handled by
317 * sending a reply about inconsistent lengths, or 1 on success. */
318 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
319 bool check_nul, Error **errp)
320 {
321 if (size > client->optlen) {
322 return nbd_opt_invalid(client, errp,
323 "Inconsistent lengths in option %s",
324 nbd_opt_lookup(client->opt));
325 }
326 client->optlen -= size;
327 if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) {
328 return -EIO;
329 }
330
331 if (check_nul && strnlen(buffer, size) != size) {
332 return nbd_opt_invalid(client, errp,
333 "Unexpected embedded NUL in option %s",
334 nbd_opt_lookup(client->opt));
335 }
336 return 1;
337 }
338
339 /* Drop size bytes from the unparsed payload of the current option.
340 * Return -errno on I/O error, 0 if option was completely handled by
341 * sending a reply about inconsistent lengths, or 1 on success. */
342 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
343 {
344 if (size > client->optlen) {
345 return nbd_opt_invalid(client, errp,
346 "Inconsistent lengths in option %s",
347 nbd_opt_lookup(client->opt));
348 }
349 client->optlen -= size;
350 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
351 }
352
353 /* nbd_opt_read_name
354 *
355 * Read a string with the format:
356 * uint32_t len (<= NBD_MAX_STRING_SIZE)
357 * len bytes string (not 0-terminated)
358 *
359 * On success, @name will be allocated.
360 * If @length is non-null, it will be set to the actual string length.
361 *
362 * Return -errno on I/O error, 0 if option was completely handled by
363 * sending a reply about inconsistent lengths, or 1 on success.
364 */
365 static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
366 Error **errp)
367 {
368 int ret;
369 uint32_t len;
370 g_autofree char *local_name = NULL;
371
372 *name = NULL;
373 ret = nbd_opt_read(client, &len, sizeof(len), false, errp);
374 if (ret <= 0) {
375 return ret;
376 }
377 len = cpu_to_be32(len);
378
379 if (len > NBD_MAX_STRING_SIZE) {
380 return nbd_opt_invalid(client, errp,
381 "Invalid name length: %" PRIu32, len);
382 }
383
384 local_name = g_malloc(len + 1);
385 ret = nbd_opt_read(client, local_name, len, true, errp);
386 if (ret <= 0) {
387 return ret;
388 }
389 local_name[len] = '\0';
390
391 if (length) {
392 *length = len;
393 }
394 *name = g_steal_pointer(&local_name);
395
396 return 1;
397 }
398
399 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
400 * Return -errno on error, 0 on success. */
401 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
402 Error **errp)
403 {
404 ERRP_GUARD();
405 size_t name_len, desc_len;
406 uint32_t len;
407 const char *name = exp->name ? exp->name : "";
408 const char *desc = exp->description ? exp->description : "";
409 QIOChannel *ioc = client->ioc;
410 int ret;
411
412 trace_nbd_negotiate_send_rep_list(name, desc);
413 name_len = strlen(name);
414 desc_len = strlen(desc);
415 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE);
416 len = name_len + desc_len + sizeof(len);
417 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
418 if (ret < 0) {
419 return ret;
420 }
421
422 len = cpu_to_be32(name_len);
423 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
424 error_prepend(errp, "write failed (name length): ");
425 return -EINVAL;
426 }
427
428 if (nbd_write(ioc, name, name_len, errp) < 0) {
429 error_prepend(errp, "write failed (name buffer): ");
430 return -EINVAL;
431 }
432
433 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
434 error_prepend(errp, "write failed (description buffer): ");
435 return -EINVAL;
436 }
437
438 return 0;
439 }
440
441 /* Process the NBD_OPT_LIST command, with a potential series of replies.
442 * Return -errno on error, 0 on success. */
443 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
444 {
445 NBDExport *exp;
446 assert(client->opt == NBD_OPT_LIST);
447
448 /* For each export, send a NBD_REP_SERVER reply. */
449 QTAILQ_FOREACH(exp, &exports, next) {
450 if (nbd_negotiate_send_rep_list(client, exp, errp)) {
451 return -EINVAL;
452 }
453 }
454 /* Finish with a NBD_REP_ACK. */
455 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
456 }
457
458 static void nbd_check_meta_export(NBDClient *client)
459 {
460 if (client->exp != client->export_meta.exp) {
461 client->export_meta.count = 0;
462 }
463 }
464
465 /* Send a reply to NBD_OPT_EXPORT_NAME.
466 * Return -errno on error, 0 on success. */
467 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
468 Error **errp)
469 {
470 ERRP_GUARD();
471 g_autofree char *name = NULL;
472 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
473 size_t len;
474 int ret;
475 uint16_t myflags;
476
477 /* Client sends:
478 [20 .. xx] export name (length bytes)
479 Server replies:
480 [ 0 .. 7] size
481 [ 8 .. 9] export flags
482 [10 .. 133] reserved (0) [unless no_zeroes]
483 */
484 trace_nbd_negotiate_handle_export_name();
485 if (client->optlen > NBD_MAX_STRING_SIZE) {
486 error_setg(errp, "Bad length received");
487 return -EINVAL;
488 }
489 name = g_malloc(client->optlen + 1);
490 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) {
491 return -EIO;
492 }
493 name[client->optlen] = '\0';
494 client->optlen = 0;
495
496 trace_nbd_negotiate_handle_export_name_request(name);
497
498 client->exp = nbd_export_find(name);
499 if (!client->exp) {
500 error_setg(errp, "export not found");
501 return -EINVAL;
502 }
503
504 myflags = client->exp->nbdflags;
505 if (client->mode >= NBD_MODE_STRUCTURED) {
506 myflags |= NBD_FLAG_SEND_DF;
507 }
508 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags);
509 stq_be_p(buf, client->exp->size);
510 stw_be_p(buf + 8, myflags);
511 len = no_zeroes ? 10 : sizeof(buf);
512 ret = nbd_write(client->ioc, buf, len, errp);
513 if (ret < 0) {
514 error_prepend(errp, "write failed: ");
515 return ret;
516 }
517
518 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
519 blk_exp_ref(&client->exp->common);
520 nbd_check_meta_export(client);
521
522 return 0;
523 }
524
525 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
526 * The buffer does NOT include the info type prefix.
527 * Return -errno on error, 0 if ready to send more. */
528 static int nbd_negotiate_send_info(NBDClient *client,
529 uint16_t info, uint32_t length, void *buf,
530 Error **errp)
531 {
532 int rc;
533
534 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
535 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
536 sizeof(info) + length, errp);
537 if (rc < 0) {
538 return rc;
539 }
540 info = cpu_to_be16(info);
541 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
542 return -EIO;
543 }
544 if (nbd_write(client->ioc, buf, length, errp) < 0) {
545 return -EIO;
546 }
547 return 0;
548 }
549
550 /* nbd_reject_length: Handle any unexpected payload.
551 * @fatal requests that we quit talking to the client, even if we are able
552 * to successfully send an error reply.
553 * Return:
554 * -errno transmission error occurred or @fatal was requested, errp is set
555 * 0 error message successfully sent to client, errp is not set
556 */
557 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
558 {
559 int ret;
560
561 assert(client->optlen);
562 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",
563 nbd_opt_lookup(client->opt));
564 if (fatal && !ret) {
565 error_setg(errp, "option '%s' has unexpected length",
566 nbd_opt_lookup(client->opt));
567 return -EINVAL;
568 }
569 return ret;
570 }
571
572 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
573 * Return -errno on error, 0 if ready for next option, and 1 to move
574 * into transmission phase. */
575 static int nbd_negotiate_handle_info(NBDClient *client, Error **errp)
576 {
577 int rc;
578 g_autofree char *name = NULL;
579 NBDExport *exp;
580 uint16_t requests;
581 uint16_t request;
582 uint32_t namelen = 0;
583 bool sendname = false;
584 bool blocksize = false;
585 uint32_t sizes[3];
586 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
587 uint32_t check_align = 0;
588 uint16_t myflags;
589
590 /* Client sends:
591 4 bytes: L, name length (can be 0)
592 L bytes: export name
593 2 bytes: N, number of requests (can be 0)
594 N * 2 bytes: N requests
595 */
596 rc = nbd_opt_read_name(client, &name, &namelen, errp);
597 if (rc <= 0) {
598 return rc;
599 }
600 trace_nbd_negotiate_handle_export_name_request(name);
601
602 rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp);
603 if (rc <= 0) {
604 return rc;
605 }
606 requests = be16_to_cpu(requests);
607 trace_nbd_negotiate_handle_info_requests(requests);
608 while (requests--) {
609 rc = nbd_opt_read(client, &request, sizeof(request), false, errp);
610 if (rc <= 0) {
611 return rc;
612 }
613 request = be16_to_cpu(request);
614 trace_nbd_negotiate_handle_info_request(request,
615 nbd_info_lookup(request));
616 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
617 * everything else is either a request we don't know or
618 * something we send regardless of request */
619 switch (request) {
620 case NBD_INFO_NAME:
621 sendname = true;
622 break;
623 case NBD_INFO_BLOCK_SIZE:
624 blocksize = true;
625 break;
626 }
627 }
628 if (client->optlen) {
629 return nbd_reject_length(client, false, errp);
630 }
631
632 exp = nbd_export_find(name);
633 if (!exp) {
634 g_autofree char *sane_name = nbd_sanitize_name(name);
635
636 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
637 errp, "export '%s' not present",
638 sane_name);
639 }
640
641 /* Don't bother sending NBD_INFO_NAME unless client requested it */
642 if (sendname) {
643 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
644 errp);
645 if (rc < 0) {
646 return rc;
647 }
648 }
649
650 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
651 * client request */
652 if (exp->description) {
653 size_t len = strlen(exp->description);
654
655 assert(len <= NBD_MAX_STRING_SIZE);
656 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
657 len, exp->description, errp);
658 if (rc < 0) {
659 return rc;
660 }
661 }
662
663 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
664 * according to whether the client requested it, and according to
665 * whether this is OPT_INFO or OPT_GO. */
666 /* minimum - 1 for back-compat, or actual if client will obey it. */
667 if (client->opt == NBD_OPT_INFO || blocksize) {
668 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk);
669 } else {
670 sizes[0] = 1;
671 }
672 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE);
673 /* preferred - Hard-code to 4096 for now.
674 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
675 sizes[1] = MAX(4096, sizes[0]);
676 /* maximum - At most 32M, but smaller as appropriate. */
677 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE);
678 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
679 sizes[0] = cpu_to_be32(sizes[0]);
680 sizes[1] = cpu_to_be32(sizes[1]);
681 sizes[2] = cpu_to_be32(sizes[2]);
682 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
683 sizeof(sizes), sizes, errp);
684 if (rc < 0) {
685 return rc;
686 }
687
688 /* Send NBD_INFO_EXPORT always */
689 myflags = exp->nbdflags;
690 if (client->mode >= NBD_MODE_STRUCTURED) {
691 myflags |= NBD_FLAG_SEND_DF;
692 }
693 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags);
694 stq_be_p(buf, exp->size);
695 stw_be_p(buf + 8, myflags);
696 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
697 sizeof(buf), buf, errp);
698 if (rc < 0) {
699 return rc;
700 }
701
702 /*
703 * If the client is just asking for NBD_OPT_INFO, but forgot to
704 * request block sizes in a situation that would impact
705 * performance, then return an error. But for NBD_OPT_GO, we
706 * tolerate all clients, regardless of alignments.
707 */
708 if (client->opt == NBD_OPT_INFO && !blocksize &&
709 blk_get_request_alignment(exp->common.blk) > 1) {
710 return nbd_negotiate_send_rep_err(client,
711 NBD_REP_ERR_BLOCK_SIZE_REQD,
712 errp,
713 "request NBD_INFO_BLOCK_SIZE to "
714 "use this export");
715 }
716
717 /* Final reply */
718 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
719 if (rc < 0) {
720 return rc;
721 }
722
723 if (client->opt == NBD_OPT_GO) {
724 client->exp = exp;
725 client->check_align = check_align;
726 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
727 blk_exp_ref(&client->exp->common);
728 nbd_check_meta_export(client);
729 rc = 1;
730 }
731 return rc;
732 }
733
734
735 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
736 * new channel for all further (now-encrypted) communication. */
737 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
738 Error **errp)
739 {
740 QIOChannel *ioc;
741 QIOChannelTLS *tioc;
742 struct NBDTLSHandshakeData data = { 0 };
743
744 assert(client->opt == NBD_OPT_STARTTLS);
745
746 trace_nbd_negotiate_handle_starttls();
747 ioc = client->ioc;
748
749 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
750 return NULL;
751 }
752
753 tioc = qio_channel_tls_new_server(ioc,
754 client->tlscreds,
755 client->tlsauthz,
756 errp);
757 if (!tioc) {
758 return NULL;
759 }
760
761 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
762 trace_nbd_negotiate_handle_starttls_handshake();
763 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
764 qio_channel_tls_handshake(tioc,
765 nbd_tls_handshake,
766 &data,
767 NULL,
768 NULL);
769
770 if (!data.complete) {
771 g_main_loop_run(data.loop);
772 }
773 g_main_loop_unref(data.loop);
774 if (data.error) {
775 object_unref(OBJECT(tioc));
776 error_propagate(errp, data.error);
777 return NULL;
778 }
779
780 return QIO_CHANNEL(tioc);
781 }
782
783 /* nbd_negotiate_send_meta_context
784 *
785 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
786 *
787 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
788 */
789 static int nbd_negotiate_send_meta_context(NBDClient *client,
790 const char *context,
791 uint32_t context_id,
792 Error **errp)
793 {
794 NBDOptionReplyMetaContext opt;
795 struct iovec iov[] = {
796 {.iov_base = &opt, .iov_len = sizeof(opt)},
797 {.iov_base = (void *)context, .iov_len = strlen(context)}
798 };
799
800 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE);
801 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
802 context_id = 0;
803 }
804
805 trace_nbd_negotiate_meta_query_reply(context, context_id);
806 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
807 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
808 stl_be_p(&opt.context_id, context_id);
809
810 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
811 }
812
813 /*
814 * Return true if @query matches @pattern, or if @query is empty when
815 * the @client is performing _LIST_.
816 */
817 static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
818 const char *query)
819 {
820 if (!*query) {
821 trace_nbd_negotiate_meta_query_parse("empty");
822 return client->opt == NBD_OPT_LIST_META_CONTEXT;
823 }
824 if (strcmp(query, pattern) == 0) {
825 trace_nbd_negotiate_meta_query_parse(pattern);
826 return true;
827 }
828 trace_nbd_negotiate_meta_query_skip("pattern not matched");
829 return false;
830 }
831
832 /*
833 * Return true and adjust @str in place if it begins with @prefix.
834 */
835 static bool nbd_strshift(const char **str, const char *prefix)
836 {
837 size_t len = strlen(prefix);
838
839 if (strncmp(*str, prefix, len) == 0) {
840 *str += len;
841 return true;
842 }
843 return false;
844 }
845
846 /* nbd_meta_base_query
847 *
848 * Handle queries to 'base' namespace. For now, only the base:allocation
849 * context is available. Return true if @query has been handled.
850 */
851 static bool nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
852 const char *query)
853 {
854 if (!nbd_strshift(&query, "base:")) {
855 return false;
856 }
857 trace_nbd_negotiate_meta_query_parse("base:");
858
859 if (nbd_meta_empty_or_pattern(client, "allocation", query)) {
860 meta->base_allocation = true;
861 }
862 return true;
863 }
864
865 /* nbd_meta_qemu_query
866 *
867 * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap:
868 * and qemu:allocation-depth contexts are available. Return true if @query
869 * has been handled.
870 */
871 static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
872 const char *query)
873 {
874 size_t i;
875
876 if (!nbd_strshift(&query, "qemu:")) {
877 return false;
878 }
879 trace_nbd_negotiate_meta_query_parse("qemu:");
880
881 if (!*query) {
882 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
883 meta->allocation_depth = meta->exp->allocation_depth;
884 if (meta->exp->nr_export_bitmaps) {
885 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
886 }
887 }
888 trace_nbd_negotiate_meta_query_parse("empty");
889 return true;
890 }
891
892 if (strcmp(query, "allocation-depth") == 0) {
893 trace_nbd_negotiate_meta_query_parse("allocation-depth");
894 meta->allocation_depth = meta->exp->allocation_depth;
895 return true;
896 }
897
898 if (nbd_strshift(&query, "dirty-bitmap:")) {
899 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
900 if (!*query) {
901 if (client->opt == NBD_OPT_LIST_META_CONTEXT &&
902 meta->exp->nr_export_bitmaps) {
903 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
904 }
905 trace_nbd_negotiate_meta_query_parse("empty");
906 return true;
907 }
908
909 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) {
910 const char *bm_name;
911
912 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]);
913 if (strcmp(bm_name, query) == 0) {
914 meta->bitmaps[i] = true;
915 trace_nbd_negotiate_meta_query_parse(query);
916 return true;
917 }
918 }
919 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap match");
920 return true;
921 }
922
923 trace_nbd_negotiate_meta_query_skip("unknown qemu context");
924 return true;
925 }
926
927 /* nbd_negotiate_meta_query
928 *
929 * Parse namespace name and call corresponding function to parse body of the
930 * query.
931 *
932 * The only supported namespaces are 'base' and 'qemu'.
933 *
934 * Return -errno on I/O error, 0 if option was completely handled by
935 * sending a reply about inconsistent lengths, or 1 on success. */
936 static int nbd_negotiate_meta_query(NBDClient *client,
937 NBDExportMetaContexts *meta, Error **errp)
938 {
939 int ret;
940 g_autofree char *query = NULL;
941 uint32_t len;
942
943 ret = nbd_opt_read(client, &len, sizeof(len), false, errp);
944 if (ret <= 0) {
945 return ret;
946 }
947 len = cpu_to_be32(len);
948
949 if (len > NBD_MAX_STRING_SIZE) {
950 trace_nbd_negotiate_meta_query_skip("length too long");
951 return nbd_opt_skip(client, len, errp);
952 }
953
954 query = g_malloc(len + 1);
955 ret = nbd_opt_read(client, query, len, true, errp);
956 if (ret <= 0) {
957 return ret;
958 }
959 query[len] = '\0';
960
961 if (nbd_meta_base_query(client, meta, query)) {
962 return 1;
963 }
964 if (nbd_meta_qemu_query(client, meta, query)) {
965 return 1;
966 }
967
968 trace_nbd_negotiate_meta_query_skip("unknown namespace");
969 return 1;
970 }
971
972 /* nbd_negotiate_meta_queries
973 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
974 *
975 * Return -errno on I/O error, or 0 if option was completely handled. */
976 static int nbd_negotiate_meta_queries(NBDClient *client,
977 NBDExportMetaContexts *meta, Error **errp)
978 {
979 int ret;
980 g_autofree char *export_name = NULL;
981 /* Mark unused to work around https://bugs.llvm.org/show_bug.cgi?id=3888 */
982 g_autofree G_GNUC_UNUSED bool *bitmaps = NULL;
983 NBDExportMetaContexts local_meta = {0};
984 uint32_t nb_queries;
985 size_t i;
986 size_t count = 0;
987
988 if (client->opt == NBD_OPT_SET_META_CONTEXT &&
989 client->mode < NBD_MODE_STRUCTURED) {
990 return nbd_opt_invalid(client, errp,
991 "request option '%s' when structured reply "
992 "is not negotiated",
993 nbd_opt_lookup(client->opt));
994 }
995
996 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
997 /* Only change the caller's meta on SET. */
998 meta = &local_meta;
999 }
1000
1001 g_free(meta->bitmaps);
1002 memset(meta, 0, sizeof(*meta));
1003
1004 ret = nbd_opt_read_name(client, &export_name, NULL, errp);
1005 if (ret <= 0) {
1006 return ret;
1007 }
1008
1009 meta->exp = nbd_export_find(export_name);
1010 if (meta->exp == NULL) {
1011 g_autofree char *sane_name = nbd_sanitize_name(export_name);
1012
1013 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
1014 "export '%s' not present", sane_name);
1015 }
1016 meta->bitmaps = g_new0(bool, meta->exp->nr_export_bitmaps);
1017 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
1018 bitmaps = meta->bitmaps;
1019 }
1020
1021 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp);
1022 if (ret <= 0) {
1023 return ret;
1024 }
1025 nb_queries = cpu_to_be32(nb_queries);
1026 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
1027 export_name, nb_queries);
1028
1029 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
1030 /* enable all known contexts */
1031 meta->base_allocation = true;
1032 meta->allocation_depth = meta->exp->allocation_depth;
1033 if (meta->exp->nr_export_bitmaps) {
1034 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
1035 }
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 count++;
1053 }
1054
1055 if (meta->allocation_depth) {
1056 ret = nbd_negotiate_send_meta_context(client, "qemu:allocation-depth",
1057 NBD_META_ID_ALLOCATION_DEPTH,
1058 errp);
1059 if (ret < 0) {
1060 return ret;
1061 }
1062 count++;
1063 }
1064
1065 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) {
1066 const char *bm_name;
1067 g_autofree char *context = NULL;
1068
1069 if (!meta->bitmaps[i]) {
1070 continue;
1071 }
1072
1073 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]);
1074 context = g_strdup_printf("qemu:dirty-bitmap:%s", bm_name);
1075
1076 ret = nbd_negotiate_send_meta_context(client, context,
1077 NBD_META_ID_DIRTY_BITMAP + i,
1078 errp);
1079 if (ret < 0) {
1080 return ret;
1081 }
1082 count++;
1083 }
1084
1085 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1086 if (ret == 0) {
1087 meta->count = count;
1088 }
1089
1090 return ret;
1091 }
1092
1093 /* nbd_negotiate_options
1094 * Process all NBD_OPT_* client option commands, during fixed newstyle
1095 * negotiation.
1096 * Return:
1097 * -errno on error, errp is set
1098 * 0 on successful negotiation, errp is not set
1099 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1100 * errp is not set
1101 */
1102 static int nbd_negotiate_options(NBDClient *client, Error **errp)
1103 {
1104 uint32_t flags;
1105 bool fixedNewstyle = false;
1106 bool no_zeroes = false;
1107
1108 /* Client sends:
1109 [ 0 .. 3] client flags
1110
1111 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
1112 [ 0 .. 7] NBD_OPTS_MAGIC
1113 [ 8 .. 11] NBD option
1114 [12 .. 15] Data length
1115 ... Rest of request
1116
1117 [ 0 .. 7] NBD_OPTS_MAGIC
1118 [ 8 .. 11] Second NBD option
1119 [12 .. 15] Data length
1120 ... Rest of request
1121 */
1122
1123 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) {
1124 return -EIO;
1125 }
1126 client->mode = NBD_MODE_EXPORT_NAME;
1127 trace_nbd_negotiate_options_flags(flags);
1128 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
1129 fixedNewstyle = true;
1130 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
1131 client->mode = NBD_MODE_SIMPLE;
1132 }
1133 if (flags & NBD_FLAG_C_NO_ZEROES) {
1134 no_zeroes = true;
1135 flags &= ~NBD_FLAG_C_NO_ZEROES;
1136 }
1137 if (flags != 0) {
1138 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
1139 return -EINVAL;
1140 }
1141
1142 while (1) {
1143 int ret;
1144 uint32_t option, length;
1145 uint64_t magic;
1146
1147 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) {
1148 return -EINVAL;
1149 }
1150 trace_nbd_negotiate_options_check_magic(magic);
1151 if (magic != NBD_OPTS_MAGIC) {
1152 error_setg(errp, "Bad magic received");
1153 return -EINVAL;
1154 }
1155
1156 if (nbd_read32(client->ioc, &option, "option", errp) < 0) {
1157 return -EINVAL;
1158 }
1159 client->opt = option;
1160
1161 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) {
1162 return -EINVAL;
1163 }
1164 assert(!client->optlen);
1165 client->optlen = length;
1166
1167 if (length > NBD_MAX_BUFFER_SIZE) {
1168 error_setg(errp, "len (%" PRIu32 ") is larger than max len (%u)",
1169 length, NBD_MAX_BUFFER_SIZE);
1170 return -EINVAL;
1171 }
1172
1173 trace_nbd_negotiate_options_check_option(option,
1174 nbd_opt_lookup(option));
1175 if (client->tlscreds &&
1176 client->ioc == (QIOChannel *)client->sioc) {
1177 QIOChannel *tioc;
1178 if (!fixedNewstyle) {
1179 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
1180 return -EINVAL;
1181 }
1182 switch (option) {
1183 case NBD_OPT_STARTTLS:
1184 if (length) {
1185 /* Unconditionally drop the connection if the client
1186 * can't start a TLS negotiation correctly */
1187 return nbd_reject_length(client, true, errp);
1188 }
1189 tioc = nbd_negotiate_handle_starttls(client, errp);
1190 if (!tioc) {
1191 return -EIO;
1192 }
1193 ret = 0;
1194 object_unref(OBJECT(client->ioc));
1195 client->ioc = tioc;
1196 break;
1197
1198 case NBD_OPT_EXPORT_NAME:
1199 /* No way to return an error to client, so drop connection */
1200 error_setg(errp, "Option 0x%x not permitted before TLS",
1201 option);
1202 return -EINVAL;
1203
1204 default:
1205 /* Let the client keep trying, unless they asked to
1206 * quit. Always try to give an error back to the
1207 * client; but when replying to OPT_ABORT, be aware
1208 * that the client may hang up before receiving the
1209 * error, in which case we are fine ignoring the
1210 * resulting EPIPE. */
1211 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD,
1212 option == NBD_OPT_ABORT ? NULL : errp,
1213 "Option 0x%" PRIx32
1214 " not permitted before TLS", option);
1215 if (option == NBD_OPT_ABORT) {
1216 return 1;
1217 }
1218 break;
1219 }
1220 } else if (fixedNewstyle) {
1221 switch (option) {
1222 case NBD_OPT_LIST:
1223 if (length) {
1224 ret = nbd_reject_length(client, false, errp);
1225 } else {
1226 ret = nbd_negotiate_handle_list(client, errp);
1227 }
1228 break;
1229
1230 case NBD_OPT_ABORT:
1231 /* NBD spec says we must try to reply before
1232 * disconnecting, but that we must also tolerate
1233 * guests that don't wait for our reply. */
1234 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL);
1235 return 1;
1236
1237 case NBD_OPT_EXPORT_NAME:
1238 return nbd_negotiate_handle_export_name(client, no_zeroes,
1239 errp);
1240
1241 case NBD_OPT_INFO:
1242 case NBD_OPT_GO:
1243 ret = nbd_negotiate_handle_info(client, errp);
1244 if (ret == 1) {
1245 assert(option == NBD_OPT_GO);
1246 return 0;
1247 }
1248 break;
1249
1250 case NBD_OPT_STARTTLS:
1251 if (length) {
1252 ret = nbd_reject_length(client, false, errp);
1253 } else if (client->tlscreds) {
1254 ret = nbd_negotiate_send_rep_err(client,
1255 NBD_REP_ERR_INVALID, errp,
1256 "TLS already enabled");
1257 } else {
1258 ret = nbd_negotiate_send_rep_err(client,
1259 NBD_REP_ERR_POLICY, errp,
1260 "TLS not configured");
1261 }
1262 break;
1263
1264 case NBD_OPT_STRUCTURED_REPLY:
1265 if (length) {
1266 ret = nbd_reject_length(client, false, errp);
1267 } else if (client->mode >= NBD_MODE_STRUCTURED) {
1268 ret = nbd_negotiate_send_rep_err(
1269 client, NBD_REP_ERR_INVALID, errp,
1270 "structured reply already negotiated");
1271 } else {
1272 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1273 client->mode = NBD_MODE_STRUCTURED;
1274 }
1275 break;
1276
1277 case NBD_OPT_LIST_META_CONTEXT:
1278 case NBD_OPT_SET_META_CONTEXT:
1279 ret = nbd_negotiate_meta_queries(client, &client->export_meta,
1280 errp);
1281 break;
1282
1283 default:
1284 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,
1285 "Unsupported option %" PRIu32 " (%s)",
1286 option, nbd_opt_lookup(option));
1287 break;
1288 }
1289 } else {
1290 /*
1291 * If broken new-style we should drop the connection
1292 * for anything except NBD_OPT_EXPORT_NAME
1293 */
1294 switch (option) {
1295 case NBD_OPT_EXPORT_NAME:
1296 return nbd_negotiate_handle_export_name(client, no_zeroes,
1297 errp);
1298
1299 default:
1300 error_setg(errp, "Unsupported option %" PRIu32 " (%s)",
1301 option, nbd_opt_lookup(option));
1302 return -EINVAL;
1303 }
1304 }
1305 if (ret < 0) {
1306 return ret;
1307 }
1308 }
1309 }
1310
1311 /* nbd_negotiate
1312 * Return:
1313 * -errno on error, errp is set
1314 * 0 on successful negotiation, errp is not set
1315 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1316 * errp is not set
1317 */
1318 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
1319 {
1320 ERRP_GUARD();
1321 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
1322 int ret;
1323
1324 /* Old style negotiation header, no room for options
1325 [ 0 .. 7] passwd ("NBDMAGIC")
1326 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
1327 [16 .. 23] size
1328 [24 .. 27] export flags (zero-extended)
1329 [28 .. 151] reserved (0)
1330
1331 New style negotiation header, client can send options
1332 [ 0 .. 7] passwd ("NBDMAGIC")
1333 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
1334 [16 .. 17] server flags (0)
1335 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
1336 */
1337
1338 qio_channel_set_blocking(client->ioc, false, NULL);
1339 qio_channel_set_follow_coroutine_ctx(client->ioc, true);
1340
1341 trace_nbd_negotiate_begin();
1342 memcpy(buf, "NBDMAGIC", 8);
1343
1344 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
1345 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
1346
1347 if (nbd_write(client->ioc, buf, 18, errp) < 0) {
1348 error_prepend(errp, "write failed: ");
1349 return -EINVAL;
1350 }
1351 ret = nbd_negotiate_options(client, errp);
1352 if (ret != 0) {
1353 if (ret < 0) {
1354 error_prepend(errp, "option negotiation failed: ");
1355 }
1356 return ret;
1357 }
1358
1359 assert(!client->optlen);
1360 trace_nbd_negotiate_success();
1361
1362 return 0;
1363 }
1364
1365 /* nbd_read_eof
1366 * Tries to read @size bytes from @ioc. This is a local implementation of
1367 * qio_channel_readv_all_eof. We have it here because we need it to be
1368 * interruptible and to know when the coroutine is yielding.
1369 * Returns 1 on success
1370 * 0 on eof, when no data was read (errp is not set)
1371 * negative errno on failure (errp is set)
1372 */
1373 static inline int coroutine_fn
1374 nbd_read_eof(NBDClient *client, void *buffer, size_t size, Error **errp)
1375 {
1376 bool partial = false;
1377
1378 assert(size);
1379 while (size > 0) {
1380 struct iovec iov = { .iov_base = buffer, .iov_len = size };
1381 ssize_t len;
1382
1383 len = qio_channel_readv(client->ioc, &iov, 1, errp);
1384 if (len == QIO_CHANNEL_ERR_BLOCK) {
1385 client->read_yielding = true;
1386 qio_channel_yield(client->ioc, G_IO_IN);
1387 client->read_yielding = false;
1388 if (client->quiescing) {
1389 return -EAGAIN;
1390 }
1391 continue;
1392 } else if (len < 0) {
1393 return -EIO;
1394 } else if (len == 0) {
1395 if (partial) {
1396 error_setg(errp,
1397 "Unexpected end-of-file before all bytes were read");
1398 return -EIO;
1399 } else {
1400 return 0;
1401 }
1402 }
1403
1404 partial = true;
1405 size -= len;
1406 buffer = (uint8_t *) buffer + len;
1407 }
1408 return 1;
1409 }
1410
1411 static int coroutine_fn nbd_receive_request(NBDClient *client, NBDRequest *request,
1412 Error **errp)
1413 {
1414 uint8_t buf[NBD_EXTENDED_REQUEST_SIZE];
1415 uint32_t magic, expect;
1416 int ret;
1417 size_t size = client->mode >= NBD_MODE_EXTENDED ?
1418 NBD_EXTENDED_REQUEST_SIZE : NBD_REQUEST_SIZE;
1419
1420 ret = nbd_read_eof(client, buf, size, errp);
1421 if (ret < 0) {
1422 return ret;
1423 }
1424 if (ret == 0) {
1425 return -EIO;
1426 }
1427
1428 /*
1429 * Compact request
1430 * [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
1431 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
1432 * [ 6 .. 7] type (NBD_CMD_READ, ...)
1433 * [ 8 .. 15] cookie
1434 * [16 .. 23] from
1435 * [24 .. 27] len
1436 * Extended request
1437 * [ 0 .. 3] magic (NBD_EXTENDED_REQUEST_MAGIC)
1438 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, NBD_CMD_FLAG_PAYLOAD_LEN, ...)
1439 * [ 6 .. 7] type (NBD_CMD_READ, ...)
1440 * [ 8 .. 15] cookie
1441 * [16 .. 23] from
1442 * [24 .. 31] len
1443 */
1444
1445 magic = ldl_be_p(buf);
1446 request->flags = lduw_be_p(buf + 4);
1447 request->type = lduw_be_p(buf + 6);
1448 request->cookie = ldq_be_p(buf + 8);
1449 request->from = ldq_be_p(buf + 16);
1450 if (client->mode >= NBD_MODE_EXTENDED) {
1451 request->len = ldq_be_p(buf + 24);
1452 expect = NBD_EXTENDED_REQUEST_MAGIC;
1453 } else {
1454 request->len = (uint32_t)ldl_be_p(buf + 24); /* widen 32 to 64 bits */
1455 expect = NBD_REQUEST_MAGIC;
1456 }
1457
1458 trace_nbd_receive_request(magic, request->flags, request->type,
1459 request->from, request->len);
1460
1461 if (magic != expect) {
1462 error_setg(errp, "invalid magic (got 0x%" PRIx32 ", expected 0x%"
1463 PRIx32 ")", magic, expect);
1464 return -EINVAL;
1465 }
1466 return 0;
1467 }
1468
1469 #define MAX_NBD_REQUESTS 16
1470
1471 void nbd_client_get(NBDClient *client)
1472 {
1473 client->refcount++;
1474 }
1475
1476 void nbd_client_put(NBDClient *client)
1477 {
1478 if (--client->refcount == 0) {
1479 /* The last reference should be dropped by client->close,
1480 * which is called by client_close.
1481 */
1482 assert(client->closing);
1483
1484 object_unref(OBJECT(client->sioc));
1485 object_unref(OBJECT(client->ioc));
1486 if (client->tlscreds) {
1487 object_unref(OBJECT(client->tlscreds));
1488 }
1489 g_free(client->tlsauthz);
1490 if (client->exp) {
1491 QTAILQ_REMOVE(&client->exp->clients, client, next);
1492 blk_exp_unref(&client->exp->common);
1493 }
1494 g_free(client->export_meta.bitmaps);
1495 g_free(client);
1496 }
1497 }
1498
1499 static void client_close(NBDClient *client, bool negotiated)
1500 {
1501 if (client->closing) {
1502 return;
1503 }
1504
1505 client->closing = true;
1506
1507 /* Force requests to finish. They will drop their own references,
1508 * then we'll close the socket and free the NBDClient.
1509 */
1510 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
1511 NULL);
1512
1513 /* Also tell the client, so that they release their reference. */
1514 if (client->close_fn) {
1515 client->close_fn(client, negotiated);
1516 }
1517 }
1518
1519 static NBDRequestData *nbd_request_get(NBDClient *client)
1520 {
1521 NBDRequestData *req;
1522
1523 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
1524 client->nb_requests++;
1525
1526 req = g_new0(NBDRequestData, 1);
1527 nbd_client_get(client);
1528 req->client = client;
1529 return req;
1530 }
1531
1532 static void nbd_request_put(NBDRequestData *req)
1533 {
1534 NBDClient *client = req->client;
1535
1536 if (req->data) {
1537 qemu_vfree(req->data);
1538 }
1539 g_free(req);
1540
1541 client->nb_requests--;
1542
1543 if (client->quiescing && client->nb_requests == 0) {
1544 aio_wait_kick();
1545 }
1546
1547 nbd_client_receive_next_request(client);
1548
1549 nbd_client_put(client);
1550 }
1551
1552 static void blk_aio_attached(AioContext *ctx, void *opaque)
1553 {
1554 NBDExport *exp = opaque;
1555 NBDClient *client;
1556
1557 trace_nbd_blk_aio_attached(exp->name, ctx);
1558
1559 exp->common.ctx = ctx;
1560
1561 QTAILQ_FOREACH(client, &exp->clients, next) {
1562 assert(client->nb_requests == 0);
1563 assert(client->recv_coroutine == NULL);
1564 assert(client->send_coroutine == NULL);
1565 }
1566 }
1567
1568 static void blk_aio_detach(void *opaque)
1569 {
1570 NBDExport *exp = opaque;
1571
1572 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx);
1573
1574 exp->common.ctx = NULL;
1575 }
1576
1577 static void nbd_drained_begin(void *opaque)
1578 {
1579 NBDExport *exp = opaque;
1580 NBDClient *client;
1581
1582 QTAILQ_FOREACH(client, &exp->clients, next) {
1583 client->quiescing = true;
1584 }
1585 }
1586
1587 static void nbd_drained_end(void *opaque)
1588 {
1589 NBDExport *exp = opaque;
1590 NBDClient *client;
1591
1592 QTAILQ_FOREACH(client, &exp->clients, next) {
1593 client->quiescing = false;
1594 nbd_client_receive_next_request(client);
1595 }
1596 }
1597
1598 static bool nbd_drained_poll(void *opaque)
1599 {
1600 NBDExport *exp = opaque;
1601 NBDClient *client;
1602
1603 QTAILQ_FOREACH(client, &exp->clients, next) {
1604 if (client->nb_requests != 0) {
1605 /*
1606 * If there's a coroutine waiting for a request on nbd_read_eof()
1607 * enter it here so we don't depend on the client to wake it up.
1608 */
1609 if (client->recv_coroutine != NULL && client->read_yielding) {
1610 qio_channel_wake_read(client->ioc);
1611 }
1612
1613 return true;
1614 }
1615 }
1616
1617 return false;
1618 }
1619
1620 static void nbd_eject_notifier(Notifier *n, void *data)
1621 {
1622 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1623
1624 blk_exp_request_shutdown(&exp->common);
1625 }
1626
1627 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk)
1628 {
1629 NBDExport *nbd_exp = container_of(exp, NBDExport, common);
1630 assert(exp->drv == &blk_exp_nbd);
1631 assert(nbd_exp->eject_notifier_blk == NULL);
1632
1633 blk_ref(blk);
1634 nbd_exp->eject_notifier_blk = blk;
1635 nbd_exp->eject_notifier.notify = nbd_eject_notifier;
1636 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier);
1637 }
1638
1639 static const BlockDevOps nbd_block_ops = {
1640 .drained_begin = nbd_drained_begin,
1641 .drained_end = nbd_drained_end,
1642 .drained_poll = nbd_drained_poll,
1643 };
1644
1645 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
1646 Error **errp)
1647 {
1648 NBDExport *exp = container_of(blk_exp, NBDExport, common);
1649 BlockExportOptionsNbd *arg = &exp_args->u.nbd;
1650 const char *name = arg->name ?: exp_args->node_name;
1651 BlockBackend *blk = blk_exp->blk;
1652 int64_t size;
1653 uint64_t perm, shared_perm;
1654 bool readonly = !exp_args->writable;
1655 BlockDirtyBitmapOrStrList *bitmaps;
1656 size_t i;
1657 int ret;
1658
1659 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
1660
1661 if (!nbd_server_is_running()) {
1662 error_setg(errp, "NBD server not running");
1663 return -EINVAL;
1664 }
1665
1666 if (strlen(name) > NBD_MAX_STRING_SIZE) {
1667 error_setg(errp, "export name '%s' too long", name);
1668 return -EINVAL;
1669 }
1670
1671 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) {
1672 error_setg(errp, "description '%s' too long", arg->description);
1673 return -EINVAL;
1674 }
1675
1676 if (nbd_export_find(name)) {
1677 error_setg(errp, "NBD server already has export named '%s'", name);
1678 return -EEXIST;
1679 }
1680
1681 size = blk_getlength(blk);
1682 if (size < 0) {
1683 error_setg_errno(errp, -size,
1684 "Failed to determine the NBD export's length");
1685 return size;
1686 }
1687
1688 /* Don't allow resize while the NBD server is running, otherwise we don't
1689 * care what happens with the node. */
1690 blk_get_perm(blk, &perm, &shared_perm);
1691 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp);
1692 if (ret < 0) {
1693 return ret;
1694 }
1695
1696 QTAILQ_INIT(&exp->clients);
1697 exp->name = g_strdup(name);
1698 exp->description = g_strdup(arg->description);
1699 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH |
1700 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE);
1701
1702 if (nbd_server_max_connections() != 1) {
1703 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
1704 }
1705 if (readonly) {
1706 exp->nbdflags |= NBD_FLAG_READ_ONLY;
1707 } else {
1708 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES |
1709 NBD_FLAG_SEND_FAST_ZERO);
1710 }
1711 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
1712
1713 for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) {
1714 exp->nr_export_bitmaps++;
1715 }
1716 exp->export_bitmaps = g_new0(BdrvDirtyBitmap *, exp->nr_export_bitmaps);
1717 for (i = 0, bitmaps = arg->bitmaps; bitmaps;
1718 i++, bitmaps = bitmaps->next)
1719 {
1720 const char *bitmap;
1721 BlockDriverState *bs = blk_bs(blk);
1722 BdrvDirtyBitmap *bm = NULL;
1723
1724 switch (bitmaps->value->type) {
1725 case QTYPE_QSTRING:
1726 bitmap = bitmaps->value->u.local;
1727 while (bs) {
1728 bm = bdrv_find_dirty_bitmap(bs, bitmap);
1729 if (bm != NULL) {
1730 break;
1731 }
1732
1733 bs = bdrv_filter_or_cow_bs(bs);
1734 }
1735
1736 if (bm == NULL) {
1737 ret = -ENOENT;
1738 error_setg(errp, "Bitmap '%s' is not found",
1739 bitmaps->value->u.local);
1740 goto fail;
1741 }
1742
1743 if (readonly && bdrv_is_writable(bs) &&
1744 bdrv_dirty_bitmap_enabled(bm)) {
1745 ret = -EINVAL;
1746 error_setg(errp, "Enabled bitmap '%s' incompatible with "
1747 "readonly export", bitmap);
1748 goto fail;
1749 }
1750 break;
1751 case QTYPE_QDICT:
1752 bitmap = bitmaps->value->u.external.name;
1753 bm = block_dirty_bitmap_lookup(bitmaps->value->u.external.node,
1754 bitmap, NULL, errp);
1755 if (!bm) {
1756 ret = -ENOENT;
1757 goto fail;
1758 }
1759 break;
1760 default:
1761 abort();
1762 }
1763
1764 assert(bm);
1765
1766 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
1767 ret = -EINVAL;
1768 goto fail;
1769 }
1770
1771 exp->export_bitmaps[i] = bm;
1772 assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE);
1773 }
1774
1775 /* Mark bitmaps busy in a separate loop, to simplify roll-back concerns. */
1776 for (i = 0; i < exp->nr_export_bitmaps; i++) {
1777 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true);
1778 }
1779
1780 exp->allocation_depth = arg->allocation_depth;
1781
1782 /*
1783 * We need to inhibit request queuing in the block layer to ensure we can
1784 * be properly quiesced when entering a drained section, as our coroutines
1785 * servicing pending requests might enter blk_pread().
1786 */
1787 blk_set_disable_request_queuing(blk, true);
1788
1789 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1790
1791 blk_set_dev_ops(blk, &nbd_block_ops, exp);
1792
1793 QTAILQ_INSERT_TAIL(&exports, exp, next);
1794
1795 return 0;
1796
1797 fail:
1798 g_free(exp->export_bitmaps);
1799 g_free(exp->name);
1800 g_free(exp->description);
1801 return ret;
1802 }
1803
1804 NBDExport *nbd_export_find(const char *name)
1805 {
1806 NBDExport *exp;
1807 QTAILQ_FOREACH(exp, &exports, next) {
1808 if (strcmp(name, exp->name) == 0) {
1809 return exp;
1810 }
1811 }
1812
1813 return NULL;
1814 }
1815
1816 AioContext *
1817 nbd_export_aio_context(NBDExport *exp)
1818 {
1819 return exp->common.ctx;
1820 }
1821
1822 static void nbd_export_request_shutdown(BlockExport *blk_exp)
1823 {
1824 NBDExport *exp = container_of(blk_exp, NBDExport, common);
1825 NBDClient *client, *next;
1826
1827 blk_exp_ref(&exp->common);
1828 /*
1829 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a
1830 * close mode that stops advertising the export to new clients but
1831 * still permits existing clients to run to completion? Because of
1832 * that possibility, nbd_export_close() can be called more than
1833 * once on an export.
1834 */
1835 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1836 client_close(client, true);
1837 }
1838 if (exp->name) {
1839 g_free(exp->name);
1840 exp->name = NULL;
1841 QTAILQ_REMOVE(&exports, exp, next);
1842 }
1843 blk_exp_unref(&exp->common);
1844 }
1845
1846 static void nbd_export_delete(BlockExport *blk_exp)
1847 {
1848 size_t i;
1849 NBDExport *exp = container_of(blk_exp, NBDExport, common);
1850
1851 assert(exp->name == NULL);
1852 assert(QTAILQ_EMPTY(&exp->clients));
1853
1854 g_free(exp->description);
1855 exp->description = NULL;
1856
1857 if (exp->eject_notifier_blk) {
1858 notifier_remove(&exp->eject_notifier);
1859 blk_unref(exp->eject_notifier_blk);
1860 }
1861 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached,
1862 blk_aio_detach, exp);
1863 blk_set_disable_request_queuing(exp->common.blk, false);
1864
1865 for (i = 0; i < exp->nr_export_bitmaps; i++) {
1866 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], false);
1867 }
1868 }
1869
1870 const BlockExportDriver blk_exp_nbd = {
1871 .type = BLOCK_EXPORT_TYPE_NBD,
1872 .instance_size = sizeof(NBDExport),
1873 .create = nbd_export_create,
1874 .delete = nbd_export_delete,
1875 .request_shutdown = nbd_export_request_shutdown,
1876 };
1877
1878 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
1879 unsigned niov, Error **errp)
1880 {
1881 int ret;
1882
1883 g_assert(qemu_in_coroutine());
1884 qemu_co_mutex_lock(&client->send_lock);
1885 client->send_coroutine = qemu_coroutine_self();
1886
1887 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
1888
1889 client->send_coroutine = NULL;
1890 qemu_co_mutex_unlock(&client->send_lock);
1891
1892 return ret;
1893 }
1894
1895 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
1896 uint64_t cookie)
1897 {
1898 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
1899 stl_be_p(&reply->error, error);
1900 stq_be_p(&reply->cookie, cookie);
1901 }
1902
1903 static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client,
1904 NBDRequest *request,
1905 uint32_t error,
1906 void *data,
1907 uint64_t len,
1908 Error **errp)
1909 {
1910 NBDSimpleReply reply;
1911 int nbd_err = system_errno_to_nbd_errno(error);
1912 struct iovec iov[] = {
1913 {.iov_base = &reply, .iov_len = sizeof(reply)},
1914 {.iov_base = data, .iov_len = len}
1915 };
1916
1917 assert(!len || !nbd_err);
1918 assert(len <= NBD_MAX_BUFFER_SIZE);
1919 assert(client->mode < NBD_MODE_STRUCTURED ||
1920 (client->mode == NBD_MODE_STRUCTURED &&
1921 request->type != NBD_CMD_READ));
1922 trace_nbd_co_send_simple_reply(request->cookie, nbd_err,
1923 nbd_err_lookup(nbd_err), len);
1924 set_be_simple_reply(&reply, nbd_err, request->cookie);
1925
1926 return nbd_co_send_iov(client, iov, 2, errp);
1927 }
1928
1929 /*
1930 * Prepare the header of a reply chunk for network transmission.
1931 *
1932 * On input, @iov is partially initialized: iov[0].iov_base must point
1933 * to an uninitialized NBDReply, while the remaining @niov elements
1934 * (if any) must be ready for transmission. This function then
1935 * populates iov[0] for transmission.
1936 */
1937 static inline void set_be_chunk(NBDClient *client, struct iovec *iov,
1938 size_t niov, uint16_t flags, uint16_t type,
1939 NBDRequest *request)
1940 {
1941 size_t i, length = 0;
1942
1943 for (i = 1; i < niov; i++) {
1944 length += iov[i].iov_len;
1945 }
1946 assert(length <= NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData));
1947
1948 if (client->mode >= NBD_MODE_EXTENDED) {
1949 NBDExtendedReplyChunk *chunk = iov->iov_base;
1950
1951 iov[0].iov_len = sizeof(*chunk);
1952 stl_be_p(&chunk->magic, NBD_EXTENDED_REPLY_MAGIC);
1953 stw_be_p(&chunk->flags, flags);
1954 stw_be_p(&chunk->type, type);
1955 stq_be_p(&chunk->cookie, request->cookie);
1956 stq_be_p(&chunk->offset, request->from);
1957 stq_be_p(&chunk->length, length);
1958 } else {
1959 NBDStructuredReplyChunk *chunk = iov->iov_base;
1960
1961 iov[0].iov_len = sizeof(*chunk);
1962 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
1963 stw_be_p(&chunk->flags, flags);
1964 stw_be_p(&chunk->type, type);
1965 stq_be_p(&chunk->cookie, request->cookie);
1966 stl_be_p(&chunk->length, length);
1967 }
1968 }
1969
1970 static int coroutine_fn nbd_co_send_chunk_done(NBDClient *client,
1971 NBDRequest *request,
1972 Error **errp)
1973 {
1974 NBDReply hdr;
1975 struct iovec iov[] = {
1976 {.iov_base = &hdr},
1977 };
1978
1979 trace_nbd_co_send_chunk_done(request->cookie);
1980 set_be_chunk(client, iov, 1, NBD_REPLY_FLAG_DONE,
1981 NBD_REPLY_TYPE_NONE, request);
1982 return nbd_co_send_iov(client, iov, 1, errp);
1983 }
1984
1985 static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client,
1986 NBDRequest *request,
1987 uint64_t offset,
1988 void *data,
1989 uint64_t size,
1990 bool final,
1991 Error **errp)
1992 {
1993 NBDReply hdr;
1994 NBDStructuredReadData chunk;
1995 struct iovec iov[] = {
1996 {.iov_base = &hdr},
1997 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1998 {.iov_base = data, .iov_len = size}
1999 };
2000
2001 assert(size && size <= NBD_MAX_BUFFER_SIZE);
2002 trace_nbd_co_send_chunk_read(request->cookie, offset, data, size);
2003 set_be_chunk(client, iov, 3, final ? NBD_REPLY_FLAG_DONE : 0,
2004 NBD_REPLY_TYPE_OFFSET_DATA, request);
2005 stq_be_p(&chunk.offset, offset);
2006
2007 return nbd_co_send_iov(client, iov, 3, errp);
2008 }
2009
2010 static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client,
2011 NBDRequest *request,
2012 uint32_t error,
2013 const char *msg,
2014 Error **errp)
2015 {
2016 NBDReply hdr;
2017 NBDStructuredError chunk;
2018 int nbd_err = system_errno_to_nbd_errno(error);
2019 struct iovec iov[] = {
2020 {.iov_base = &hdr},
2021 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
2022 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
2023 };
2024
2025 assert(nbd_err);
2026 trace_nbd_co_send_chunk_error(request->cookie, nbd_err,
2027 nbd_err_lookup(nbd_err), msg ? msg : "");
2028 set_be_chunk(client, iov, 3, NBD_REPLY_FLAG_DONE,
2029 NBD_REPLY_TYPE_ERROR, request);
2030 stl_be_p(&chunk.error, nbd_err);
2031 stw_be_p(&chunk.message_length, iov[2].iov_len);
2032
2033 return nbd_co_send_iov(client, iov, 3, errp);
2034 }
2035
2036 /* Do a sparse read and send the structured reply to the client.
2037 * Returns -errno if sending fails. blk_co_block_status_above() failure is
2038 * reported to the client, at which point this function succeeds.
2039 */
2040 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
2041 NBDRequest *request,
2042 uint64_t offset,
2043 uint8_t *data,
2044 uint64_t size,
2045 Error **errp)
2046 {
2047 int ret = 0;
2048 NBDExport *exp = client->exp;
2049 size_t progress = 0;
2050
2051 assert(size <= NBD_MAX_BUFFER_SIZE);
2052 while (progress < size) {
2053 int64_t pnum;
2054 int status = blk_co_block_status_above(exp->common.blk, NULL,
2055 offset + progress,
2056 size - progress, &pnum, NULL,
2057 NULL);
2058 bool final;
2059
2060 if (status < 0) {
2061 char *msg = g_strdup_printf("unable to check for holes: %s",
2062 strerror(-status));
2063
2064 ret = nbd_co_send_chunk_error(client, request, -status, msg, errp);
2065 g_free(msg);
2066 return ret;
2067 }
2068 assert(pnum && pnum <= size - progress);
2069 final = progress + pnum == size;
2070 if (status & BDRV_BLOCK_ZERO) {
2071 NBDReply hdr;
2072 NBDStructuredReadHole chunk;
2073 struct iovec iov[] = {
2074 {.iov_base = &hdr},
2075 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
2076 };
2077
2078 trace_nbd_co_send_chunk_read_hole(request->cookie,
2079 offset + progress, pnum);
2080 set_be_chunk(client, iov, 2,
2081 final ? NBD_REPLY_FLAG_DONE : 0,
2082 NBD_REPLY_TYPE_OFFSET_HOLE, request);
2083 stq_be_p(&chunk.offset, offset + progress);
2084 stl_be_p(&chunk.length, pnum);
2085 ret = nbd_co_send_iov(client, iov, 2, errp);
2086 } else {
2087 ret = blk_co_pread(exp->common.blk, offset + progress, pnum,
2088 data + progress, 0);
2089 if (ret < 0) {
2090 error_setg_errno(errp, -ret, "reading from file failed");
2091 break;
2092 }
2093 ret = nbd_co_send_chunk_read(client, request, offset + progress,
2094 data + progress, pnum, final, errp);
2095 }
2096
2097 if (ret < 0) {
2098 break;
2099 }
2100 progress += pnum;
2101 }
2102 return ret;
2103 }
2104
2105 typedef struct NBDExtentArray {
2106 NBDExtent32 *extents;
2107 unsigned int nb_alloc;
2108 unsigned int count;
2109 uint64_t total_length;
2110 bool can_add;
2111 bool converted_to_be;
2112 } NBDExtentArray;
2113
2114 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc)
2115 {
2116 NBDExtentArray *ea = g_new0(NBDExtentArray, 1);
2117
2118 ea->nb_alloc = nb_alloc;
2119 ea->extents = g_new(NBDExtent32, nb_alloc);
2120 ea->can_add = true;
2121
2122 return ea;
2123 }
2124
2125 static void nbd_extent_array_free(NBDExtentArray *ea)
2126 {
2127 g_free(ea->extents);
2128 g_free(ea);
2129 }
2130 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free)
2131
2132 /* Further modifications of the array after conversion are abandoned */
2133 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea)
2134 {
2135 int i;
2136
2137 assert(!ea->converted_to_be);
2138 ea->can_add = false;
2139 ea->converted_to_be = true;
2140
2141 for (i = 0; i < ea->count; i++) {
2142 ea->extents[i].flags = cpu_to_be32(ea->extents[i].flags);
2143 ea->extents[i].length = cpu_to_be32(ea->extents[i].length);
2144 }
2145 }
2146
2147 /*
2148 * Add extent to NBDExtentArray. If extent can't be added (no available space),
2149 * return -1.
2150 * For safety, when returning -1 for the first time, .can_add is set to false,
2151 * and further calls to nbd_extent_array_add() will crash.
2152 * (this avoids the situation where a caller ignores failure to add one extent,
2153 * where adding another extent that would squash into the last array entry
2154 * would result in an incorrect range reported to the client)
2155 */
2156 static int nbd_extent_array_add(NBDExtentArray *ea,
2157 uint32_t length, uint32_t flags)
2158 {
2159 assert(ea->can_add);
2160
2161 if (!length) {
2162 return 0;
2163 }
2164
2165 /* Extend previous extent if flags are the same */
2166 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) {
2167 uint64_t sum = (uint64_t)length + ea->extents[ea->count - 1].length;
2168
2169 if (sum <= UINT32_MAX) {
2170 ea->extents[ea->count - 1].length = sum;
2171 ea->total_length += length;
2172 return 0;
2173 }
2174 }
2175
2176 if (ea->count >= ea->nb_alloc) {
2177 ea->can_add = false;
2178 return -1;
2179 }
2180
2181 ea->total_length += length;
2182 ea->extents[ea->count] = (NBDExtent32) {.length = length, .flags = flags};
2183 ea->count++;
2184
2185 return 0;
2186 }
2187
2188 static int coroutine_fn blockstatus_to_extents(BlockBackend *blk,
2189 uint64_t offset, uint64_t bytes,
2190 NBDExtentArray *ea)
2191 {
2192 while (bytes) {
2193 uint32_t flags;
2194 int64_t num;
2195 int ret = blk_co_block_status_above(blk, NULL, offset, bytes, &num,
2196 NULL, NULL);
2197
2198 if (ret < 0) {
2199 return ret;
2200 }
2201
2202 flags = (ret & BDRV_BLOCK_DATA ? 0 : NBD_STATE_HOLE) |
2203 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
2204
2205 if (nbd_extent_array_add(ea, num, flags) < 0) {
2206 return 0;
2207 }
2208
2209 offset += num;
2210 bytes -= num;
2211 }
2212
2213 return 0;
2214 }
2215
2216 static int coroutine_fn blockalloc_to_extents(BlockBackend *blk,
2217 uint64_t offset, uint64_t bytes,
2218 NBDExtentArray *ea)
2219 {
2220 while (bytes) {
2221 int64_t num;
2222 int ret = blk_co_is_allocated_above(blk, NULL, false, offset, bytes,
2223 &num);
2224
2225 if (ret < 0) {
2226 return ret;
2227 }
2228
2229 if (nbd_extent_array_add(ea, num, ret) < 0) {
2230 return 0;
2231 }
2232
2233 offset += num;
2234 bytes -= num;
2235 }
2236
2237 return 0;
2238 }
2239
2240 /*
2241 * nbd_co_send_extents
2242 *
2243 * @ea is converted to BE by the function
2244 * @last controls whether NBD_REPLY_FLAG_DONE is sent.
2245 */
2246 static int coroutine_fn
2247 nbd_co_send_extents(NBDClient *client, NBDRequest *request, NBDExtentArray *ea,
2248 bool last, uint32_t context_id, Error **errp)
2249 {
2250 NBDReply hdr;
2251 NBDStructuredMeta chunk;
2252 struct iovec iov[] = {
2253 {.iov_base = &hdr},
2254 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
2255 {.iov_base = ea->extents, .iov_len = ea->count * sizeof(ea->extents[0])}
2256 };
2257
2258 nbd_extent_array_convert_to_be(ea);
2259
2260 trace_nbd_co_send_extents(request->cookie, ea->count, context_id,
2261 ea->total_length, last);
2262 set_be_chunk(client, iov, 3, last ? NBD_REPLY_FLAG_DONE : 0,
2263 NBD_REPLY_TYPE_BLOCK_STATUS, request);
2264 stl_be_p(&chunk.context_id, context_id);
2265
2266 return nbd_co_send_iov(client, iov, 3, errp);
2267 }
2268
2269 /* Get block status from the exported device and send it to the client */
2270 static int
2271 coroutine_fn nbd_co_send_block_status(NBDClient *client, NBDRequest *request,
2272 BlockBackend *blk, uint64_t offset,
2273 uint32_t length, bool dont_fragment,
2274 bool last, uint32_t context_id,
2275 Error **errp)
2276 {
2277 int ret;
2278 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
2279 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
2280
2281 if (context_id == NBD_META_ID_BASE_ALLOCATION) {
2282 ret = blockstatus_to_extents(blk, offset, length, ea);
2283 } else {
2284 ret = blockalloc_to_extents(blk, offset, length, ea);
2285 }
2286 if (ret < 0) {
2287 return nbd_co_send_chunk_error(client, request, -ret,
2288 "can't get block status", errp);
2289 }
2290
2291 return nbd_co_send_extents(client, request, ea, last, context_id, errp);
2292 }
2293
2294 /* Populate @ea from a dirty bitmap. */
2295 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap,
2296 uint64_t offset, uint64_t length,
2297 NBDExtentArray *es)
2298 {
2299 int64_t start, dirty_start, dirty_count;
2300 int64_t end = offset + length;
2301 bool full = false;
2302
2303 bdrv_dirty_bitmap_lock(bitmap);
2304
2305 for (start = offset;
2306 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX,
2307 &dirty_start, &dirty_count);
2308 start = dirty_start + dirty_count)
2309 {
2310 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) ||
2311 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0))
2312 {
2313 full = true;
2314 break;
2315 }
2316 }
2317
2318 if (!full) {
2319 /* last non dirty extent, nothing to do if array is now full */
2320 (void) nbd_extent_array_add(es, end - start, 0);
2321 }
2322
2323 bdrv_dirty_bitmap_unlock(bitmap);
2324 }
2325
2326 static int coroutine_fn nbd_co_send_bitmap(NBDClient *client,
2327 NBDRequest *request,
2328 BdrvDirtyBitmap *bitmap,
2329 uint64_t offset,
2330 uint32_t length, bool dont_fragment,
2331 bool last, uint32_t context_id,
2332 Error **errp)
2333 {
2334 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
2335 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
2336
2337 bitmap_to_extents(bitmap, offset, length, ea);
2338
2339 return nbd_co_send_extents(client, request, ea, last, context_id, errp);
2340 }
2341
2342 /* nbd_co_receive_request
2343 * Collect a client request. Return 0 if request looks valid, -EIO to drop
2344 * connection right away, -EAGAIN to indicate we were interrupted and the
2345 * channel should be quiesced, and any other negative value to report an error
2346 * to the client (although the caller may still need to disconnect after
2347 * reporting the error).
2348 */
2349 static int coroutine_fn nbd_co_receive_request(NBDRequestData *req,
2350 NBDRequest *request,
2351 Error **errp)
2352 {
2353 NBDClient *client = req->client;
2354 bool extended_with_payload;
2355 bool check_length = false;
2356 bool check_rofs = false;
2357 bool allocate_buffer = false;
2358 bool payload_okay = false;
2359 uint64_t payload_len = 0;
2360 int valid_flags = NBD_CMD_FLAG_FUA;
2361 int ret;
2362
2363 g_assert(qemu_in_coroutine());
2364 assert(client->recv_coroutine == qemu_coroutine_self());
2365 ret = nbd_receive_request(client, request, errp);
2366 if (ret < 0) {
2367 return ret;
2368 }
2369
2370 trace_nbd_co_receive_request_decode_type(request->cookie, request->type,
2371 nbd_cmd_lookup(request->type));
2372 extended_with_payload = client->mode >= NBD_MODE_EXTENDED &&
2373 request->flags & NBD_CMD_FLAG_PAYLOAD_LEN;
2374 if (extended_with_payload) {
2375 payload_len = request->len;
2376 check_length = true;
2377 }
2378
2379 switch (request->type) {
2380 case NBD_CMD_DISC:
2381 /* Special case: we're going to disconnect without a reply,
2382 * whether or not flags, from, or len are bogus */
2383 req->complete = true;
2384 return -EIO;
2385
2386 case NBD_CMD_READ:
2387 if (client->mode >= NBD_MODE_STRUCTURED) {
2388 valid_flags |= NBD_CMD_FLAG_DF;
2389 }
2390 check_length = true;
2391 allocate_buffer = true;
2392 break;
2393
2394 case NBD_CMD_WRITE:
2395 if (client->mode >= NBD_MODE_EXTENDED) {
2396 if (!extended_with_payload) {
2397 /* The client is noncompliant. Trace it, but proceed. */
2398 trace_nbd_co_receive_ext_payload_compliance(request->from,
2399 request->len);
2400 }
2401 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN;
2402 }
2403 payload_okay = true;
2404 payload_len = request->len;
2405 check_length = true;
2406 allocate_buffer = true;
2407 check_rofs = true;
2408 break;
2409
2410 case NBD_CMD_FLUSH:
2411 break;
2412
2413 case NBD_CMD_TRIM:
2414 check_rofs = true;
2415 break;
2416
2417 case NBD_CMD_CACHE:
2418 check_length = true;
2419 break;
2420
2421 case NBD_CMD_WRITE_ZEROES:
2422 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO;
2423 check_rofs = true;
2424 break;
2425
2426 case NBD_CMD_BLOCK_STATUS:
2427 valid_flags |= NBD_CMD_FLAG_REQ_ONE;
2428 break;
2429
2430 default:
2431 /* Unrecognized, will fail later */
2432 ;
2433 }
2434
2435 /* Payload and buffer handling. */
2436 if (!payload_len) {
2437 req->complete = true;
2438 }
2439 if (check_length && request->len > NBD_MAX_BUFFER_SIZE) {
2440 /* READ, WRITE, CACHE */
2441 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)",
2442 request->len, NBD_MAX_BUFFER_SIZE);
2443 return -EINVAL;
2444 }
2445 if (payload_len && !payload_okay) {
2446 /*
2447 * For now, we don't support payloads on other commands; but
2448 * we can keep the connection alive by ignoring the payload.
2449 * We will fail the command later with NBD_EINVAL for the use
2450 * of an unsupported flag (and not for access beyond bounds).
2451 */
2452 assert(request->type != NBD_CMD_WRITE);
2453 request->len = 0;
2454 }
2455 if (allocate_buffer) {
2456 /* READ, WRITE */
2457 req->data = blk_try_blockalign(client->exp->common.blk,
2458 request->len);
2459 if (req->data == NULL) {
2460 error_setg(errp, "No memory");
2461 return -ENOMEM;
2462 }
2463 }
2464 if (payload_len) {
2465 if (payload_okay) {
2466 /* WRITE */
2467 assert(req->data);
2468 ret = nbd_read(client->ioc, req->data, payload_len,
2469 "CMD_WRITE data", errp);
2470 } else {
2471 ret = nbd_drop(client->ioc, payload_len, errp);
2472 }
2473 if (ret < 0) {
2474 return -EIO;
2475 }
2476 req->complete = true;
2477 trace_nbd_co_receive_request_payload_received(request->cookie,
2478 payload_len);
2479 }
2480
2481 /* Sanity checks. */
2482 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && check_rofs) {
2483 /* WRITE, TRIM, WRITE_ZEROES */
2484 error_setg(errp, "Export is read-only");
2485 return -EROFS;
2486 }
2487 if (request->from > client->exp->size ||
2488 request->len > client->exp->size - request->from) {
2489 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu64
2490 ", Size: %" PRIu64, request->from, request->len,
2491 client->exp->size);
2492 return (request->type == NBD_CMD_WRITE ||
2493 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
2494 }
2495 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len,
2496 client->check_align)) {
2497 /*
2498 * The block layer gracefully handles unaligned requests, but
2499 * it's still worth tracing client non-compliance
2500 */
2501 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type),
2502 request->from,
2503 request->len,
2504 client->check_align);
2505 }
2506 if (request->flags & ~valid_flags) {
2507 error_setg(errp, "unsupported flags for command %s (got 0x%x)",
2508 nbd_cmd_lookup(request->type), request->flags);
2509 return -EINVAL;
2510 }
2511
2512 return 0;
2513 }
2514
2515 /* Send simple reply without a payload, or a structured error
2516 * @error_msg is ignored if @ret >= 0
2517 * Returns 0 if connection is still live, -errno on failure to talk to client
2518 */
2519 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
2520 NBDRequest *request,
2521 int ret,
2522 const char *error_msg,
2523 Error **errp)
2524 {
2525 if (client->mode >= NBD_MODE_STRUCTURED && ret < 0) {
2526 return nbd_co_send_chunk_error(client, request, -ret, error_msg, errp);
2527 } else if (client->mode >= NBD_MODE_EXTENDED) {
2528 return nbd_co_send_chunk_done(client, request, errp);
2529 } else {
2530 return nbd_co_send_simple_reply(client, request, ret < 0 ? -ret : 0,
2531 NULL, 0, errp);
2532 }
2533 }
2534
2535 /* Handle NBD_CMD_READ request.
2536 * Return -errno if sending fails. Other errors are reported directly to the
2537 * client as an error reply. */
2538 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
2539 uint8_t *data, Error **errp)
2540 {
2541 int ret;
2542 NBDExport *exp = client->exp;
2543
2544 assert(request->type == NBD_CMD_READ);
2545 assert(request->len <= NBD_MAX_BUFFER_SIZE);
2546
2547 /* XXX: NBD Protocol only documents use of FUA with WRITE */
2548 if (request->flags & NBD_CMD_FLAG_FUA) {
2549 ret = blk_co_flush(exp->common.blk);
2550 if (ret < 0) {
2551 return nbd_send_generic_reply(client, request, ret,
2552 "flush failed", errp);
2553 }
2554 }
2555
2556 if (client->mode >= NBD_MODE_STRUCTURED &&
2557 !(request->flags & NBD_CMD_FLAG_DF) && request->len)
2558 {
2559 return nbd_co_send_sparse_read(client, request, request->from,
2560 data, request->len, errp);
2561 }
2562
2563 ret = blk_co_pread(exp->common.blk, request->from, request->len, data, 0);
2564 if (ret < 0) {
2565 return nbd_send_generic_reply(client, request, ret,
2566 "reading from file failed", errp);
2567 }
2568
2569 if (client->mode >= NBD_MODE_STRUCTURED) {
2570 if (request->len) {
2571 return nbd_co_send_chunk_read(client, request, request->from, data,
2572 request->len, true, errp);
2573 } else {
2574 return nbd_co_send_chunk_done(client, request, errp);
2575 }
2576 } else {
2577 return nbd_co_send_simple_reply(client, request, 0,
2578 data, request->len, errp);
2579 }
2580 }
2581
2582 /*
2583 * nbd_do_cmd_cache
2584 *
2585 * Handle NBD_CMD_CACHE request.
2586 * Return -errno if sending fails. Other errors are reported directly to the
2587 * client as an error reply.
2588 */
2589 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request,
2590 Error **errp)
2591 {
2592 int ret;
2593 NBDExport *exp = client->exp;
2594
2595 assert(request->type == NBD_CMD_CACHE);
2596 assert(request->len <= NBD_MAX_BUFFER_SIZE);
2597
2598 ret = blk_co_preadv(exp->common.blk, request->from, request->len,
2599 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH);
2600
2601 return nbd_send_generic_reply(client, request, ret,
2602 "caching data failed", errp);
2603 }
2604
2605 /* Handle NBD request.
2606 * Return -errno if sending fails. Other errors are reported directly to the
2607 * client as an error reply. */
2608 static coroutine_fn int nbd_handle_request(NBDClient *client,
2609 NBDRequest *request,
2610 uint8_t *data, Error **errp)
2611 {
2612 int ret;
2613 int flags;
2614 NBDExport *exp = client->exp;
2615 char *msg;
2616 size_t i;
2617
2618 switch (request->type) {
2619 case NBD_CMD_CACHE:
2620 return nbd_do_cmd_cache(client, request, errp);
2621
2622 case NBD_CMD_READ:
2623 return nbd_do_cmd_read(client, request, data, errp);
2624
2625 case NBD_CMD_WRITE:
2626 flags = 0;
2627 if (request->flags & NBD_CMD_FLAG_FUA) {
2628 flags |= BDRV_REQ_FUA;
2629 }
2630 assert(request->len <= NBD_MAX_BUFFER_SIZE);
2631 ret = blk_co_pwrite(exp->common.blk, request->from, request->len, data,
2632 flags);
2633 return nbd_send_generic_reply(client, request, ret,
2634 "writing to file failed", errp);
2635
2636 case NBD_CMD_WRITE_ZEROES:
2637 flags = 0;
2638 if (request->flags & NBD_CMD_FLAG_FUA) {
2639 flags |= BDRV_REQ_FUA;
2640 }
2641 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) {
2642 flags |= BDRV_REQ_MAY_UNMAP;
2643 }
2644 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) {
2645 flags |= BDRV_REQ_NO_FALLBACK;
2646 }
2647 ret = blk_co_pwrite_zeroes(exp->common.blk, request->from, request->len,
2648 flags);
2649 return nbd_send_generic_reply(client, request, ret,
2650 "writing to file failed", errp);
2651
2652 case NBD_CMD_DISC:
2653 /* unreachable, thanks to special case in nbd_co_receive_request() */
2654 abort();
2655
2656 case NBD_CMD_FLUSH:
2657 ret = blk_co_flush(exp->common.blk);
2658 return nbd_send_generic_reply(client, request, ret,
2659 "flush failed", errp);
2660
2661 case NBD_CMD_TRIM:
2662 ret = blk_co_pdiscard(exp->common.blk, request->from, request->len);
2663 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) {
2664 ret = blk_co_flush(exp->common.blk);
2665 }
2666 return nbd_send_generic_reply(client, request, ret,
2667 "discard failed", errp);
2668
2669 case NBD_CMD_BLOCK_STATUS:
2670 if (!request->len) {
2671 return nbd_send_generic_reply(client, request, -EINVAL,
2672 "need non-zero length", errp);
2673 }
2674 assert(request->len <= UINT32_MAX);
2675 if (client->export_meta.count) {
2676 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
2677 int contexts_remaining = client->export_meta.count;
2678
2679 if (client->export_meta.base_allocation) {
2680 ret = nbd_co_send_block_status(client, request,
2681 exp->common.blk,
2682 request->from,
2683 request->len, dont_fragment,
2684 !--contexts_remaining,
2685 NBD_META_ID_BASE_ALLOCATION,
2686 errp);
2687 if (ret < 0) {
2688 return ret;
2689 }
2690 }
2691
2692 if (client->export_meta.allocation_depth) {
2693 ret = nbd_co_send_block_status(client, request,
2694 exp->common.blk,
2695 request->from, request->len,
2696 dont_fragment,
2697 !--contexts_remaining,
2698 NBD_META_ID_ALLOCATION_DEPTH,
2699 errp);
2700 if (ret < 0) {
2701 return ret;
2702 }
2703 }
2704
2705 for (i = 0; i < client->exp->nr_export_bitmaps; i++) {
2706 if (!client->export_meta.bitmaps[i]) {
2707 continue;
2708 }
2709 ret = nbd_co_send_bitmap(client, request,
2710 client->exp->export_bitmaps[i],
2711 request->from, request->len,
2712 dont_fragment, !--contexts_remaining,
2713 NBD_META_ID_DIRTY_BITMAP + i, errp);
2714 if (ret < 0) {
2715 return ret;
2716 }
2717 }
2718
2719 assert(!contexts_remaining);
2720
2721 return 0;
2722 } else {
2723 return nbd_send_generic_reply(client, request, -EINVAL,
2724 "CMD_BLOCK_STATUS not negotiated",
2725 errp);
2726 }
2727
2728 default:
2729 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
2730 request->type);
2731 ret = nbd_send_generic_reply(client, request, -EINVAL, msg,
2732 errp);
2733 g_free(msg);
2734 return ret;
2735 }
2736 }
2737
2738 /* Owns a reference to the NBDClient passed as opaque. */
2739 static coroutine_fn void nbd_trip(void *opaque)
2740 {
2741 NBDClient *client = opaque;
2742 NBDRequestData *req;
2743 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
2744 int ret;
2745 Error *local_err = NULL;
2746
2747 trace_nbd_trip();
2748 if (client->closing) {
2749 nbd_client_put(client);
2750 return;
2751 }
2752
2753 if (client->quiescing) {
2754 /*
2755 * We're switching between AIO contexts. Don't attempt to receive a new
2756 * request and kick the main context which may be waiting for us.
2757 */
2758 nbd_client_put(client);
2759 client->recv_coroutine = NULL;
2760 aio_wait_kick();
2761 return;
2762 }
2763
2764 req = nbd_request_get(client);
2765 ret = nbd_co_receive_request(req, &request, &local_err);
2766 client->recv_coroutine = NULL;
2767
2768 if (client->closing) {
2769 /*
2770 * The client may be closed when we are blocked in
2771 * nbd_co_receive_request()
2772 */
2773 goto done;
2774 }
2775
2776 if (ret == -EAGAIN) {
2777 assert(client->quiescing);
2778 goto done;
2779 }
2780
2781 nbd_client_receive_next_request(client);
2782 if (ret == -EIO) {
2783 goto disconnect;
2784 }
2785
2786 qio_channel_set_cork(client->ioc, true);
2787
2788 if (ret < 0) {
2789 /* It wasn't -EIO, so, according to nbd_co_receive_request()
2790 * semantics, we should return the error to the client. */
2791 Error *export_err = local_err;
2792
2793 local_err = NULL;
2794 ret = nbd_send_generic_reply(client, &request, -EINVAL,
2795 error_get_pretty(export_err), &local_err);
2796 error_free(export_err);
2797 } else {
2798 ret = nbd_handle_request(client, &request, req->data, &local_err);
2799 }
2800 if (ret < 0) {
2801 error_prepend(&local_err, "Failed to send reply: ");
2802 goto disconnect;
2803 }
2804
2805 /* We must disconnect after NBD_CMD_WRITE if we did not
2806 * read the payload.
2807 */
2808 if (!req->complete) {
2809 error_setg(&local_err, "Request handling failed in intermediate state");
2810 goto disconnect;
2811 }
2812
2813 qio_channel_set_cork(client->ioc, false);
2814 done:
2815 nbd_request_put(req);
2816 nbd_client_put(client);
2817 return;
2818
2819 disconnect:
2820 if (local_err) {
2821 error_reportf_err(local_err, "Disconnect client, due to: ");
2822 }
2823 nbd_request_put(req);
2824 client_close(client, true);
2825 nbd_client_put(client);
2826 }
2827
2828 static void nbd_client_receive_next_request(NBDClient *client)
2829 {
2830 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS &&
2831 !client->quiescing) {
2832 nbd_client_get(client);
2833 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
2834 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine);
2835 }
2836 }
2837
2838 static coroutine_fn void nbd_co_client_start(void *opaque)
2839 {
2840 NBDClient *client = opaque;
2841 Error *local_err = NULL;
2842
2843 qemu_co_mutex_init(&client->send_lock);
2844
2845 if (nbd_negotiate(client, &local_err)) {
2846 if (local_err) {
2847 error_report_err(local_err);
2848 }
2849 client_close(client, false);
2850 return;
2851 }
2852
2853 nbd_client_receive_next_request(client);
2854 }
2855
2856 /*
2857 * Create a new client listener using the given channel @sioc.
2858 * Begin servicing it in a coroutine. When the connection closes, call
2859 * @close_fn with an indication of whether the client completed negotiation.
2860 */
2861 void nbd_client_new(QIOChannelSocket *sioc,
2862 QCryptoTLSCreds *tlscreds,
2863 const char *tlsauthz,
2864 void (*close_fn)(NBDClient *, bool))
2865 {
2866 NBDClient *client;
2867 Coroutine *co;
2868
2869 client = g_new0(NBDClient, 1);
2870 client->refcount = 1;
2871 client->tlscreds = tlscreds;
2872 if (tlscreds) {
2873 object_ref(OBJECT(client->tlscreds));
2874 }
2875 client->tlsauthz = g_strdup(tlsauthz);
2876 client->sioc = sioc;
2877 qio_channel_set_delay(QIO_CHANNEL(sioc), false);
2878 object_ref(OBJECT(client->sioc));
2879 client->ioc = QIO_CHANNEL(sioc);
2880 object_ref(OBJECT(client->ioc));
2881 client->close_fn = close_fn;
2882
2883 co = qemu_coroutine_create(nbd_co_client_start, client);
2884 qemu_coroutine_enter(co);
2885 }
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