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