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ivshmem: Fix unplug of device "ivshmem-plain"
[qemu/armbru.git] / nbd / server.c
bloba1eda0114fa3c728e0eabd5641f6a8182d9307f6
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 "trace.h"
23 #include "nbd-internal.h"
24
25 #define NBD_META_ID_BASE_ALLOCATION 0
26 #define NBD_META_ID_DIRTY_BITMAP 1
27
28 /* NBD_MAX_BITMAP_EXTENTS: 1 mb of extents data. An empirical
29 * constant. If an increase is needed, note that the NBD protocol
30 * recommends no larger than 32 mb, so that the client won't consider
31 * the reply as a denial of service attack. */
32 #define NBD_MAX_BITMAP_EXTENTS (0x100000 / 8)
33
34 static int system_errno_to_nbd_errno(int err)
35 {
36 switch (err) {
37 case 0:
38 return NBD_SUCCESS;
39 case EPERM:
40 case EROFS:
41 return NBD_EPERM;
42 case EIO:
43 return NBD_EIO;
44 case ENOMEM:
45 return NBD_ENOMEM;
46 #ifdef EDQUOT
47 case EDQUOT:
48 #endif
49 case EFBIG:
50 case ENOSPC:
51 return NBD_ENOSPC;
52 case EOVERFLOW:
53 return NBD_EOVERFLOW;
54 case ESHUTDOWN:
55 return NBD_ESHUTDOWN;
56 case EINVAL:
57 default:
58 return NBD_EINVAL;
59 }
60 }
61
62 /* Definitions for opaque data types */
63
64 typedef struct NBDRequestData NBDRequestData;
65
66 struct NBDRequestData {
67 QSIMPLEQ_ENTRY(NBDRequestData) entry;
68 NBDClient *client;
69 uint8_t *data;
70 bool complete;
71 };
72
73 struct NBDExport {
74 int refcount;
75 void (*close)(NBDExport *exp);
76
77 BlockBackend *blk;
78 char *name;
79 char *description;
80 off_t dev_offset;
81 off_t size;
82 uint16_t nbdflags;
83 QTAILQ_HEAD(, NBDClient) clients;
84 QTAILQ_ENTRY(NBDExport) next;
85
86 AioContext *ctx;
87
88 BlockBackend *eject_notifier_blk;
89 Notifier eject_notifier;
90
91 BdrvDirtyBitmap *export_bitmap;
92 char *export_bitmap_context;
93 };
94
95 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
96
97 /* NBDExportMetaContexts represents a list of contexts to be exported,
98 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for
99 * NBD_OPT_LIST_META_CONTEXT. */
100 typedef struct NBDExportMetaContexts {
101 NBDExport *exp;
102 bool valid; /* means that negotiation of the option finished without
103 errors */
104 bool base_allocation; /* export base:allocation context (block status) */
105 bool bitmap; /* export qemu:dirty-bitmap:<export bitmap name> */
106 } NBDExportMetaContexts;
107
108 struct NBDClient {
109 int refcount;
110 void (*close_fn)(NBDClient *client, bool negotiated);
111
112 NBDExport *exp;
113 QCryptoTLSCreds *tlscreds;
114 char *tlsaclname;
115 QIOChannelSocket *sioc; /* The underlying data channel */
116 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
117
118 Coroutine *recv_coroutine;
119
120 CoMutex send_lock;
121 Coroutine *send_coroutine;
122
123 QTAILQ_ENTRY(NBDClient) next;
124 int nb_requests;
125 bool closing;
126
127 bool structured_reply;
128 NBDExportMetaContexts export_meta;
129
130 uint32_t opt; /* Current option being negotiated */
131 uint32_t optlen; /* remaining length of data in ioc for the option being
132 negotiated now */
133 };
134
135 static void nbd_client_receive_next_request(NBDClient *client);
136
137 /* Basic flow for negotiation
138
139 Server Client
140 Negotiate
141
142 or
143
144 Server Client
145 Negotiate #1
146 Option
147 Negotiate #2
148
149 ----
150
151 followed by
152
153 Server Client
154 Request
155 Response
156 Request
157 Response
158 ...
159 ...
160 Request (type == 2)
161
162 */
163
164 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
165 uint32_t type, uint32_t length)
166 {
167 stq_be_p(&rep->magic, NBD_REP_MAGIC);
168 stl_be_p(&rep->option, option);
169 stl_be_p(&rep->type, type);
170 stl_be_p(&rep->length, length);
171 }
172
173 /* Send a reply header, including length, but no payload.
174 * Return -errno on error, 0 on success. */
175 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
176 uint32_t len, Error **errp)
177 {
178 NBDOptionReply rep;
179
180 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),
181 type, nbd_rep_lookup(type), len);
182
183 assert(len < NBD_MAX_BUFFER_SIZE);
184
185 set_be_option_rep(&rep, client->opt, type, len);
186 return nbd_write(client->ioc, &rep, sizeof(rep), errp);
187 }
188
189 /* Send a reply header with default 0 length.
190 * Return -errno on error, 0 on success. */
191 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
192 Error **errp)
193 {
194 return nbd_negotiate_send_rep_len(client, type, 0, errp);
195 }
196
197 /* Send an error reply.
198 * Return -errno on error, 0 on success. */
199 static int GCC_FMT_ATTR(4, 0)
200 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
201 Error **errp, const char *fmt, va_list va)
202 {
203 char *msg;
204 int ret;
205 size_t len;
206
207 msg = g_strdup_vprintf(fmt, va);
208 len = strlen(msg);
209 assert(len < 4096);
210 trace_nbd_negotiate_send_rep_err(msg);
211 ret = nbd_negotiate_send_rep_len(client, type, len, errp);
212 if (ret < 0) {
213 goto out;
214 }
215 if (nbd_write(client->ioc, msg, len, errp) < 0) {
216 error_prepend(errp, "write failed (error message): ");
217 ret = -EIO;
218 } else {
219 ret = 0;
220 }
221
222 out:
223 g_free(msg);
224 return ret;
225 }
226
227 /* Send an error reply.
228 * Return -errno on error, 0 on success. */
229 static int GCC_FMT_ATTR(4, 5)
230 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
231 Error **errp, const char *fmt, ...)
232 {
233 va_list va;
234 int ret;
235
236 va_start(va, fmt);
237 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
238 va_end(va);
239 return ret;
240 }
241
242 /* Drop remainder of the current option, and send a reply with the
243 * given error type and message. Return -errno on read or write
244 * failure; or 0 if connection is still live. */
245 static int GCC_FMT_ATTR(4, 0)
246 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
247 const char *fmt, va_list va)
248 {
249 int ret = nbd_drop(client->ioc, client->optlen, errp);
250
251 client->optlen = 0;
252 if (!ret) {
253 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
254 }
255 return ret;
256 }
257
258 static int GCC_FMT_ATTR(4, 5)
259 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
260 const char *fmt, ...)
261 {
262 int ret;
263 va_list va;
264
265 va_start(va, fmt);
266 ret = nbd_opt_vdrop(client, type, errp, fmt, va);
267 va_end(va);
268
269 return ret;
270 }
271
272 static int GCC_FMT_ATTR(3, 4)
273 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
274 {
275 int ret;
276 va_list va;
277
278 va_start(va, fmt);
279 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);
280 va_end(va);
281
282 return ret;
283 }
284
285 /* Read size bytes from the unparsed payload of the current option.
286 * Return -errno on I/O error, 0 if option was completely handled by
287 * sending a reply about inconsistent lengths, or 1 on success. */
288 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
289 Error **errp)
290 {
291 if (size > client->optlen) {
292 return nbd_opt_invalid(client, errp,
293 "Inconsistent lengths in option %s",
294 nbd_opt_lookup(client->opt));
295 }
296 client->optlen -= size;
297 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1;
298 }
299
300 /* Drop size bytes from the unparsed payload of the current option.
301 * Return -errno on I/O error, 0 if option was completely handled by
302 * sending a reply about inconsistent lengths, or 1 on success. */
303 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
304 {
305 if (size > client->optlen) {
306 return nbd_opt_invalid(client, errp,
307 "Inconsistent lengths in option %s",
308 nbd_opt_lookup(client->opt));
309 }
310 client->optlen -= size;
311 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
312 }
313
314 /* nbd_opt_read_name
315 *
316 * Read a string with the format:
317 * uint32_t len (<= NBD_MAX_NAME_SIZE)
318 * len bytes string (not 0-terminated)
319 *
320 * @name should be enough to store NBD_MAX_NAME_SIZE+1.
321 * If @length is non-null, it will be set to the actual string length.
322 *
323 * Return -errno on I/O error, 0 if option was completely handled by
324 * sending a reply about inconsistent lengths, or 1 on success.
325 */
326 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length,
327 Error **errp)
328 {
329 int ret;
330 uint32_t len;
331
332 ret = nbd_opt_read(client, &len, sizeof(len), errp);
333 if (ret <= 0) {
334 return ret;
335 }
336 len = cpu_to_be32(len);
337
338 if (len > NBD_MAX_NAME_SIZE) {
339 return nbd_opt_invalid(client, errp,
340 "Invalid name length: %" PRIu32, len);
341 }
342
343 ret = nbd_opt_read(client, name, len, errp);
344 if (ret <= 0) {
345 return ret;
346 }
347 name[len] = '\0';
348
349 if (length) {
350 *length = len;
351 }
352
353 return 1;
354 }
355
356 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
357 * Return -errno on error, 0 on success. */
358 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
359 Error **errp)
360 {
361 size_t name_len, desc_len;
362 uint32_t len;
363 const char *name = exp->name ? exp->name : "";
364 const char *desc = exp->description ? exp->description : "";
365 QIOChannel *ioc = client->ioc;
366 int ret;
367
368 trace_nbd_negotiate_send_rep_list(name, desc);
369 name_len = strlen(name);
370 desc_len = strlen(desc);
371 len = name_len + desc_len + sizeof(len);
372 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
373 if (ret < 0) {
374 return ret;
375 }
376
377 len = cpu_to_be32(name_len);
378 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
379 error_prepend(errp, "write failed (name length): ");
380 return -EINVAL;
381 }
382
383 if (nbd_write(ioc, name, name_len, errp) < 0) {
384 error_prepend(errp, "write failed (name buffer): ");
385 return -EINVAL;
386 }
387
388 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
389 error_prepend(errp, "write failed (description buffer): ");
390 return -EINVAL;
391 }
392
393 return 0;
394 }
395
396 /* Process the NBD_OPT_LIST command, with a potential series of replies.
397 * Return -errno on error, 0 on success. */
398 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
399 {
400 NBDExport *exp;
401 assert(client->opt == NBD_OPT_LIST);
402
403 /* For each export, send a NBD_REP_SERVER reply. */
404 QTAILQ_FOREACH(exp, &exports, next) {
405 if (nbd_negotiate_send_rep_list(client, exp, errp)) {
406 return -EINVAL;
407 }
408 }
409 /* Finish with a NBD_REP_ACK. */
410 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
411 }
412
413 static void nbd_check_meta_export(NBDClient *client)
414 {
415 client->export_meta.valid &= client->exp == client->export_meta.exp;
416 }
417
418 /* Send a reply to NBD_OPT_EXPORT_NAME.
419 * Return -errno on error, 0 on success. */
420 static int nbd_negotiate_handle_export_name(NBDClient *client,
421 uint16_t myflags, bool no_zeroes,
422 Error **errp)
423 {
424 char name[NBD_MAX_NAME_SIZE + 1];
425 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
426 size_t len;
427 int ret;
428
429 /* Client sends:
430 [20 .. xx] export name (length bytes)
431 Server replies:
432 [ 0 .. 7] size
433 [ 8 .. 9] export flags
434 [10 .. 133] reserved (0) [unless no_zeroes]
435 */
436 trace_nbd_negotiate_handle_export_name();
437 if (client->optlen >= sizeof(name)) {
438 error_setg(errp, "Bad length received");
439 return -EINVAL;
440 }
441 if (nbd_read(client->ioc, name, client->optlen, errp) < 0) {
442 error_prepend(errp, "read failed: ");
443 return -EIO;
444 }
445 name[client->optlen] = '\0';
446 client->optlen = 0;
447
448 trace_nbd_negotiate_handle_export_name_request(name);
449
450 client->exp = nbd_export_find(name);
451 if (!client->exp) {
452 error_setg(errp, "export not found");
453 return -EINVAL;
454 }
455
456 trace_nbd_negotiate_new_style_size_flags(client->exp->size,
457 client->exp->nbdflags | myflags);
458 stq_be_p(buf, client->exp->size);
459 stw_be_p(buf + 8, client->exp->nbdflags | myflags);
460 len = no_zeroes ? 10 : sizeof(buf);
461 ret = nbd_write(client->ioc, buf, len, errp);
462 if (ret < 0) {
463 error_prepend(errp, "write failed: ");
464 return ret;
465 }
466
467 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
468 nbd_export_get(client->exp);
469 nbd_check_meta_export(client);
470
471 return 0;
472 }
473
474 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
475 * The buffer does NOT include the info type prefix.
476 * Return -errno on error, 0 if ready to send more. */
477 static int nbd_negotiate_send_info(NBDClient *client,
478 uint16_t info, uint32_t length, void *buf,
479 Error **errp)
480 {
481 int rc;
482
483 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
484 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
485 sizeof(info) + length, errp);
486 if (rc < 0) {
487 return rc;
488 }
489 info = cpu_to_be16(info);
490 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
491 return -EIO;
492 }
493 if (nbd_write(client->ioc, buf, length, errp) < 0) {
494 return -EIO;
495 }
496 return 0;
497 }
498
499 /* nbd_reject_length: Handle any unexpected payload.
500 * @fatal requests that we quit talking to the client, even if we are able
501 * to successfully send an error reply.
502 * Return:
503 * -errno transmission error occurred or @fatal was requested, errp is set
504 * 0 error message successfully sent to client, errp is not set
505 */
506 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
507 {
508 int ret;
509
510 assert(client->optlen);
511 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",
512 nbd_opt_lookup(client->opt));
513 if (fatal && !ret) {
514 error_setg(errp, "option '%s' has unexpected length",
515 nbd_opt_lookup(client->opt));
516 return -EINVAL;
517 }
518 return ret;
519 }
520
521 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
522 * Return -errno on error, 0 if ready for next option, and 1 to move
523 * into transmission phase. */
524 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
525 Error **errp)
526 {
527 int rc;
528 char name[NBD_MAX_NAME_SIZE + 1];
529 NBDExport *exp;
530 uint16_t requests;
531 uint16_t request;
532 uint32_t namelen;
533 bool sendname = false;
534 bool blocksize = false;
535 uint32_t sizes[3];
536 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
537
538 /* Client sends:
539 4 bytes: L, name length (can be 0)
540 L bytes: export name
541 2 bytes: N, number of requests (can be 0)
542 N * 2 bytes: N requests
543 */
544 rc = nbd_opt_read_name(client, name, &namelen, errp);
545 if (rc <= 0) {
546 return rc;
547 }
548 trace_nbd_negotiate_handle_export_name_request(name);
549
550 rc = nbd_opt_read(client, &requests, sizeof(requests), errp);
551 if (rc <= 0) {
552 return rc;
553 }
554 requests = be16_to_cpu(requests);
555 trace_nbd_negotiate_handle_info_requests(requests);
556 while (requests--) {
557 rc = nbd_opt_read(client, &request, sizeof(request), errp);
558 if (rc <= 0) {
559 return rc;
560 }
561 request = be16_to_cpu(request);
562 trace_nbd_negotiate_handle_info_request(request,
563 nbd_info_lookup(request));
564 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
565 * everything else is either a request we don't know or
566 * something we send regardless of request */
567 switch (request) {
568 case NBD_INFO_NAME:
569 sendname = true;
570 break;
571 case NBD_INFO_BLOCK_SIZE:
572 blocksize = true;
573 break;
574 }
575 }
576 if (client->optlen) {
577 return nbd_reject_length(client, false, errp);
578 }
579
580 exp = nbd_export_find(name);
581 if (!exp) {
582 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
583 errp, "export '%s' not present",
584 name);
585 }
586
587 /* Don't bother sending NBD_INFO_NAME unless client requested it */
588 if (sendname) {
589 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
590 errp);
591 if (rc < 0) {
592 return rc;
593 }
594 }
595
596 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
597 * client request */
598 if (exp->description) {
599 size_t len = strlen(exp->description);
600
601 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
602 len, exp->description, errp);
603 if (rc < 0) {
604 return rc;
605 }
606 }
607
608 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
609 * according to whether the client requested it, and according to
610 * whether this is OPT_INFO or OPT_GO. */
611 /* minimum - 1 for back-compat, or 512 if client is new enough.
612 * TODO: consult blk_bs(blk)->bl.request_alignment? */
613 sizes[0] =
614 (client->opt == NBD_OPT_INFO || blocksize) ? BDRV_SECTOR_SIZE : 1;
615 /* preferred - Hard-code to 4096 for now.
616 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
617 sizes[1] = 4096;
618 /* maximum - At most 32M, but smaller as appropriate. */
619 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
620 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
621 sizes[0] = cpu_to_be32(sizes[0]);
622 sizes[1] = cpu_to_be32(sizes[1]);
623 sizes[2] = cpu_to_be32(sizes[2]);
624 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
625 sizeof(sizes), sizes, errp);
626 if (rc < 0) {
627 return rc;
628 }
629
630 /* Send NBD_INFO_EXPORT always */
631 trace_nbd_negotiate_new_style_size_flags(exp->size,
632 exp->nbdflags | myflags);
633 stq_be_p(buf, exp->size);
634 stw_be_p(buf + 8, exp->nbdflags | myflags);
635 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
636 sizeof(buf), buf, errp);
637 if (rc < 0) {
638 return rc;
639 }
640
641 /* If the client is just asking for NBD_OPT_INFO, but forgot to
642 * request block sizes, return an error.
643 * TODO: consult blk_bs(blk)->request_align, and only error if it
644 * is not 1? */
645 if (client->opt == NBD_OPT_INFO && !blocksize) {
646 return nbd_negotiate_send_rep_err(client,
647 NBD_REP_ERR_BLOCK_SIZE_REQD,
648 errp,
649 "request NBD_INFO_BLOCK_SIZE to "
650 "use this export");
651 }
652
653 /* Final reply */
654 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
655 if (rc < 0) {
656 return rc;
657 }
658
659 if (client->opt == NBD_OPT_GO) {
660 client->exp = exp;
661 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
662 nbd_export_get(client->exp);
663 nbd_check_meta_export(client);
664 rc = 1;
665 }
666 return rc;
667 }
668
669
670 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
671 * new channel for all further (now-encrypted) communication. */
672 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
673 Error **errp)
674 {
675 QIOChannel *ioc;
676 QIOChannelTLS *tioc;
677 struct NBDTLSHandshakeData data = { 0 };
678
679 assert(client->opt == NBD_OPT_STARTTLS);
680
681 trace_nbd_negotiate_handle_starttls();
682 ioc = client->ioc;
683
684 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
685 return NULL;
686 }
687
688 tioc = qio_channel_tls_new_server(ioc,
689 client->tlscreds,
690 client->tlsaclname,
691 errp);
692 if (!tioc) {
693 return NULL;
694 }
695
696 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
697 trace_nbd_negotiate_handle_starttls_handshake();
698 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
699 qio_channel_tls_handshake(tioc,
700 nbd_tls_handshake,
701 &data,
702 NULL,
703 NULL);
704
705 if (!data.complete) {
706 g_main_loop_run(data.loop);
707 }
708 g_main_loop_unref(data.loop);
709 if (data.error) {
710 object_unref(OBJECT(tioc));
711 error_propagate(errp, data.error);
712 return NULL;
713 }
714
715 return QIO_CHANNEL(tioc);
716 }
717
718 /* nbd_negotiate_send_meta_context
719 *
720 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
721 *
722 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
723 */
724 static int nbd_negotiate_send_meta_context(NBDClient *client,
725 const char *context,
726 uint32_t context_id,
727 Error **errp)
728 {
729 NBDOptionReplyMetaContext opt;
730 struct iovec iov[] = {
731 {.iov_base = &opt, .iov_len = sizeof(opt)},
732 {.iov_base = (void *)context, .iov_len = strlen(context)}
733 };
734
735 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
736 context_id = 0;
737 }
738
739 trace_nbd_negotiate_meta_query_reply(context, context_id);
740 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
741 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
742 stl_be_p(&opt.context_id, context_id);
743
744 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
745 }
746
747 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern.
748 * @match is never set to false.
749 *
750 * Return -errno on I/O error, 0 if option was completely handled by
751 * sending a reply about inconsistent lengths, or 1 on success.
752 *
753 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
754 * It only means that there are no errors.
755 */
756 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match,
757 Error **errp)
758 {
759 int ret;
760 char *query;
761 size_t len = strlen(pattern);
762
763 assert(len);
764
765 query = g_malloc(len);
766 ret = nbd_opt_read(client, query, len, errp);
767 if (ret <= 0) {
768 g_free(query);
769 return ret;
770 }
771
772 if (strncmp(query, pattern, len) == 0) {
773 trace_nbd_negotiate_meta_query_parse(pattern);
774 *match = true;
775 } else {
776 trace_nbd_negotiate_meta_query_skip("pattern not matched");
777 }
778 g_free(query);
779
780 return 1;
781 }
782
783 /*
784 * Read @len bytes, and set @match to true if they match @pattern, or if @len
785 * is 0 and the client is performing _LIST_. @match is never set to false.
786 *
787 * Return -errno on I/O error, 0 if option was completely handled by
788 * sending a reply about inconsistent lengths, or 1 on success.
789 *
790 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
791 * It only means that there are no errors.
792 */
793 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
794 uint32_t len, bool *match, Error **errp)
795 {
796 if (len == 0) {
797 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
798 *match = true;
799 }
800 trace_nbd_negotiate_meta_query_parse("empty");
801 return 1;
802 }
803
804 if (len != strlen(pattern)) {
805 trace_nbd_negotiate_meta_query_skip("different lengths");
806 return nbd_opt_skip(client, len, errp);
807 }
808
809 return nbd_meta_pattern(client, pattern, match, errp);
810 }
811
812 /* nbd_meta_base_query
813 *
814 * Handle queries to 'base' namespace. For now, only the base:allocation
815 * context is available. 'len' is the amount of text remaining to be read from
816 * the current name, after the 'base:' portion has been stripped.
817 *
818 * Return -errno on I/O error, 0 if option was completely handled by
819 * sending a reply about inconsistent lengths, or 1 on success.
820 */
821 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
822 uint32_t len, Error **errp)
823 {
824 return nbd_meta_empty_or_pattern(client, "allocation", len,
825 &meta->base_allocation, errp);
826 }
827
828 /* nbd_meta_bitmap_query
829 *
830 * Handle query to 'qemu:' namespace.
831 * @len is the amount of text remaining to be read from the current name, after
832 * the 'qemu:' portion has been stripped.
833 *
834 * Return -errno on I/O error, 0 if option was completely handled by
835 * sending a reply about inconsistent lengths, or 1 on success. */
836 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
837 uint32_t len, Error **errp)
838 {
839 bool dirty_bitmap = false;
840 size_t dirty_bitmap_len = strlen("dirty-bitmap:");
841 int ret;
842
843 if (!meta->exp->export_bitmap) {
844 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported");
845 return nbd_opt_skip(client, len, errp);
846 }
847
848 if (len == 0) {
849 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
850 meta->bitmap = true;
851 }
852 trace_nbd_negotiate_meta_query_parse("empty");
853 return 1;
854 }
855
856 if (len < dirty_bitmap_len) {
857 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
858 return nbd_opt_skip(client, len, errp);
859 }
860
861 len -= dirty_bitmap_len;
862 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp);
863 if (ret <= 0) {
864 return ret;
865 }
866 if (!dirty_bitmap) {
867 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
868 return nbd_opt_skip(client, len, errp);
869 }
870
871 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
872
873 return nbd_meta_empty_or_pattern(
874 client, meta->exp->export_bitmap_context +
875 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp);
876 }
877
878 /* nbd_negotiate_meta_query
879 *
880 * Parse namespace name and call corresponding function to parse body of the
881 * query.
882 *
883 * The only supported namespace now is 'base'.
884 *
885 * The function aims not wasting time and memory to read long unknown namespace
886 * names.
887 *
888 * Return -errno on I/O error, 0 if option was completely handled by
889 * sending a reply about inconsistent lengths, or 1 on success. */
890 static int nbd_negotiate_meta_query(NBDClient *client,
891 NBDExportMetaContexts *meta, Error **errp)
892 {
893 /*
894 * Both 'qemu' and 'base' namespaces have length = 5 including a
895 * colon. If another length namespace is later introduced, this
896 * should certainly be refactored.
897 */
898 int ret;
899 size_t ns_len = 5;
900 char ns[5];
901 uint32_t len;
902
903 ret = nbd_opt_read(client, &len, sizeof(len), errp);
904 if (ret <= 0) {
905 return ret;
906 }
907 len = cpu_to_be32(len);
908
909 if (len < ns_len) {
910 trace_nbd_negotiate_meta_query_skip("length too short");
911 return nbd_opt_skip(client, len, errp);
912 }
913
914 len -= ns_len;
915 ret = nbd_opt_read(client, ns, ns_len, errp);
916 if (ret <= 0) {
917 return ret;
918 }
919
920 if (!strncmp(ns, "base:", ns_len)) {
921 trace_nbd_negotiate_meta_query_parse("base:");
922 return nbd_meta_base_query(client, meta, len, errp);
923 } else if (!strncmp(ns, "qemu:", ns_len)) {
924 trace_nbd_negotiate_meta_query_parse("qemu:");
925 return nbd_meta_qemu_query(client, meta, len, errp);
926 }
927
928 trace_nbd_negotiate_meta_query_skip("unknown namespace");
929 return nbd_opt_skip(client, len, errp);
930 }
931
932 /* nbd_negotiate_meta_queries
933 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
934 *
935 * Return -errno on I/O error, or 0 if option was completely handled. */
936 static int nbd_negotiate_meta_queries(NBDClient *client,
937 NBDExportMetaContexts *meta, Error **errp)
938 {
939 int ret;
940 char export_name[NBD_MAX_NAME_SIZE + 1];
941 NBDExportMetaContexts local_meta;
942 uint32_t nb_queries;
943 int i;
944
945 if (!client->structured_reply) {
946 return nbd_opt_invalid(client, errp,
947 "request option '%s' when structured reply "
948 "is not negotiated",
949 nbd_opt_lookup(client->opt));
950 }
951
952 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
953 /* Only change the caller's meta on SET. */
954 meta = &local_meta;
955 }
956
957 memset(meta, 0, sizeof(*meta));
958
959 ret = nbd_opt_read_name(client, export_name, NULL, errp);
960 if (ret <= 0) {
961 return ret;
962 }
963
964 meta->exp = nbd_export_find(export_name);
965 if (meta->exp == NULL) {
966 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
967 "export '%s' not present", export_name);
968 }
969
970 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp);
971 if (ret <= 0) {
972 return ret;
973 }
974 nb_queries = cpu_to_be32(nb_queries);
975 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
976 export_name, nb_queries);
977
978 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
979 /* enable all known contexts */
980 meta->base_allocation = true;
981 } else {
982 for (i = 0; i < nb_queries; ++i) {
983 ret = nbd_negotiate_meta_query(client, meta, errp);
984 if (ret <= 0) {
985 return ret;
986 }
987 }
988 }
989
990 if (meta->base_allocation) {
991 ret = nbd_negotiate_send_meta_context(client, "base:allocation",
992 NBD_META_ID_BASE_ALLOCATION,
993 errp);
994 if (ret < 0) {
995 return ret;
996 }
997 }
998
999 if (meta->bitmap) {
1000 ret = nbd_negotiate_send_meta_context(client,
1001 meta->exp->export_bitmap_context,
1002 NBD_META_ID_DIRTY_BITMAP,
1003 errp);
1004 if (ret < 0) {
1005 return ret;
1006 }
1007 }
1008
1009 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1010 if (ret == 0) {
1011 meta->valid = true;
1012 }
1013
1014 return ret;
1015 }
1016
1017 /* nbd_negotiate_options
1018 * Process all NBD_OPT_* client option commands, during fixed newstyle
1019 * negotiation.
1020 * Return:
1021 * -errno on error, errp is set
1022 * 0 on successful negotiation, errp is not set
1023 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1024 * errp is not set
1025 */
1026 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
1027 Error **errp)
1028 {
1029 uint32_t flags;
1030 bool fixedNewstyle = false;
1031 bool no_zeroes = false;
1032
1033 /* Client sends:
1034 [ 0 .. 3] client flags
1035
1036 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
1037 [ 0 .. 7] NBD_OPTS_MAGIC
1038 [ 8 .. 11] NBD option
1039 [12 .. 15] Data length
1040 ... Rest of request
1041
1042 [ 0 .. 7] NBD_OPTS_MAGIC
1043 [ 8 .. 11] Second NBD option
1044 [12 .. 15] Data length
1045 ... Rest of request
1046 */
1047
1048 if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) {
1049 error_prepend(errp, "read failed: ");
1050 return -EIO;
1051 }
1052 flags = be32_to_cpu(flags);
1053 trace_nbd_negotiate_options_flags(flags);
1054 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
1055 fixedNewstyle = true;
1056 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
1057 }
1058 if (flags & NBD_FLAG_C_NO_ZEROES) {
1059 no_zeroes = true;
1060 flags &= ~NBD_FLAG_C_NO_ZEROES;
1061 }
1062 if (flags != 0) {
1063 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
1064 return -EINVAL;
1065 }
1066
1067 while (1) {
1068 int ret;
1069 uint32_t option, length;
1070 uint64_t magic;
1071
1072 if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) {
1073 error_prepend(errp, "read failed: ");
1074 return -EINVAL;
1075 }
1076 magic = be64_to_cpu(magic);
1077 trace_nbd_negotiate_options_check_magic(magic);
1078 if (magic != NBD_OPTS_MAGIC) {
1079 error_setg(errp, "Bad magic received");
1080 return -EINVAL;
1081 }
1082
1083 if (nbd_read(client->ioc, &option,
1084 sizeof(option), errp) < 0) {
1085 error_prepend(errp, "read failed: ");
1086 return -EINVAL;
1087 }
1088 option = be32_to_cpu(option);
1089 client->opt = option;
1090
1091 if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) {
1092 error_prepend(errp, "read failed: ");
1093 return -EINVAL;
1094 }
1095 length = be32_to_cpu(length);
1096 assert(!client->optlen);
1097 client->optlen = length;
1098
1099 if (length > NBD_MAX_BUFFER_SIZE) {
1100 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
1101 length, NBD_MAX_BUFFER_SIZE);
1102 return -EINVAL;
1103 }
1104
1105 trace_nbd_negotiate_options_check_option(option,
1106 nbd_opt_lookup(option));
1107 if (client->tlscreds &&
1108 client->ioc == (QIOChannel *)client->sioc) {
1109 QIOChannel *tioc;
1110 if (!fixedNewstyle) {
1111 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
1112 return -EINVAL;
1113 }
1114 switch (option) {
1115 case NBD_OPT_STARTTLS:
1116 if (length) {
1117 /* Unconditionally drop the connection if the client
1118 * can't start a TLS negotiation correctly */
1119 return nbd_reject_length(client, true, errp);
1120 }
1121 tioc = nbd_negotiate_handle_starttls(client, errp);
1122 if (!tioc) {
1123 return -EIO;
1124 }
1125 ret = 0;
1126 object_unref(OBJECT(client->ioc));
1127 client->ioc = QIO_CHANNEL(tioc);
1128 break;
1129
1130 case NBD_OPT_EXPORT_NAME:
1131 /* No way to return an error to client, so drop connection */
1132 error_setg(errp, "Option 0x%x not permitted before TLS",
1133 option);
1134 return -EINVAL;
1135
1136 default:
1137 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, errp,
1138 "Option 0x%" PRIx32
1139 "not permitted before TLS", option);
1140 /* Let the client keep trying, unless they asked to
1141 * quit. In this mode, we've already sent an error, so
1142 * we can't ack the abort. */
1143 if (option == NBD_OPT_ABORT) {
1144 return 1;
1145 }
1146 break;
1147 }
1148 } else if (fixedNewstyle) {
1149 switch (option) {
1150 case NBD_OPT_LIST:
1151 if (length) {
1152 ret = nbd_reject_length(client, false, errp);
1153 } else {
1154 ret = nbd_negotiate_handle_list(client, errp);
1155 }
1156 break;
1157
1158 case NBD_OPT_ABORT:
1159 /* NBD spec says we must try to reply before
1160 * disconnecting, but that we must also tolerate
1161 * guests that don't wait for our reply. */
1162 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL);
1163 return 1;
1164
1165 case NBD_OPT_EXPORT_NAME:
1166 return nbd_negotiate_handle_export_name(client,
1167 myflags, no_zeroes,
1168 errp);
1169
1170 case NBD_OPT_INFO:
1171 case NBD_OPT_GO:
1172 ret = nbd_negotiate_handle_info(client, myflags, errp);
1173 if (ret == 1) {
1174 assert(option == NBD_OPT_GO);
1175 return 0;
1176 }
1177 break;
1178
1179 case NBD_OPT_STARTTLS:
1180 if (length) {
1181 ret = nbd_reject_length(client, false, errp);
1182 } else if (client->tlscreds) {
1183 ret = nbd_negotiate_send_rep_err(client,
1184 NBD_REP_ERR_INVALID, errp,
1185 "TLS already enabled");
1186 } else {
1187 ret = nbd_negotiate_send_rep_err(client,
1188 NBD_REP_ERR_POLICY, errp,
1189 "TLS not configured");
1190 }
1191 break;
1192
1193 case NBD_OPT_STRUCTURED_REPLY:
1194 if (length) {
1195 ret = nbd_reject_length(client, false, errp);
1196 } else if (client->structured_reply) {
1197 ret = nbd_negotiate_send_rep_err(
1198 client, NBD_REP_ERR_INVALID, errp,
1199 "structured reply already negotiated");
1200 } else {
1201 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1202 client->structured_reply = true;
1203 myflags |= NBD_FLAG_SEND_DF;
1204 }
1205 break;
1206
1207 case NBD_OPT_LIST_META_CONTEXT:
1208 case NBD_OPT_SET_META_CONTEXT:
1209 ret = nbd_negotiate_meta_queries(client, &client->export_meta,
1210 errp);
1211 break;
1212
1213 default:
1214 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,
1215 "Unsupported option %" PRIu32 " (%s)",
1216 option, nbd_opt_lookup(option));
1217 break;
1218 }
1219 } else {
1220 /*
1221 * If broken new-style we should drop the connection
1222 * for anything except NBD_OPT_EXPORT_NAME
1223 */
1224 switch (option) {
1225 case NBD_OPT_EXPORT_NAME:
1226 return nbd_negotiate_handle_export_name(client,
1227 myflags, no_zeroes,
1228 errp);
1229
1230 default:
1231 error_setg(errp, "Unsupported option %" PRIu32 " (%s)",
1232 option, nbd_opt_lookup(option));
1233 return -EINVAL;
1234 }
1235 }
1236 if (ret < 0) {
1237 return ret;
1238 }
1239 }
1240 }
1241
1242 /* nbd_negotiate
1243 * Return:
1244 * -errno on error, errp is set
1245 * 0 on successful negotiation, errp is not set
1246 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1247 * errp is not set
1248 */
1249 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
1250 {
1251 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
1252 int ret;
1253 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
1254 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
1255 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE);
1256
1257 /* Old style negotiation header, no room for options
1258 [ 0 .. 7] passwd ("NBDMAGIC")
1259 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
1260 [16 .. 23] size
1261 [24 .. 27] export flags (zero-extended)
1262 [28 .. 151] reserved (0)
1263
1264 New style negotiation header, client can send options
1265 [ 0 .. 7] passwd ("NBDMAGIC")
1266 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
1267 [16 .. 17] server flags (0)
1268 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
1269 */
1270
1271 qio_channel_set_blocking(client->ioc, false, NULL);
1272
1273 trace_nbd_negotiate_begin();
1274 memcpy(buf, "NBDMAGIC", 8);
1275
1276 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
1277 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
1278
1279 if (nbd_write(client->ioc, buf, 18, errp) < 0) {
1280 error_prepend(errp, "write failed: ");
1281 return -EINVAL;
1282 }
1283 ret = nbd_negotiate_options(client, myflags, errp);
1284 if (ret != 0) {
1285 if (ret < 0) {
1286 error_prepend(errp, "option negotiation failed: ");
1287 }
1288 return ret;
1289 }
1290
1291 assert(!client->optlen);
1292 trace_nbd_negotiate_success();
1293
1294 return 0;
1295 }
1296
1297 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
1298 Error **errp)
1299 {
1300 uint8_t buf[NBD_REQUEST_SIZE];
1301 uint32_t magic;
1302 int ret;
1303
1304 ret = nbd_read(ioc, buf, sizeof(buf), errp);
1305 if (ret < 0) {
1306 return ret;
1307 }
1308
1309 /* Request
1310 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
1311 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
1312 [ 6 .. 7] type (NBD_CMD_READ, ...)
1313 [ 8 .. 15] handle
1314 [16 .. 23] from
1315 [24 .. 27] len
1316 */
1317
1318 magic = ldl_be_p(buf);
1319 request->flags = lduw_be_p(buf + 4);
1320 request->type = lduw_be_p(buf + 6);
1321 request->handle = ldq_be_p(buf + 8);
1322 request->from = ldq_be_p(buf + 16);
1323 request->len = ldl_be_p(buf + 24);
1324
1325 trace_nbd_receive_request(magic, request->flags, request->type,
1326 request->from, request->len);
1327
1328 if (magic != NBD_REQUEST_MAGIC) {
1329 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
1330 return -EINVAL;
1331 }
1332 return 0;
1333 }
1334
1335 #define MAX_NBD_REQUESTS 16
1336
1337 void nbd_client_get(NBDClient *client)
1338 {
1339 client->refcount++;
1340 }
1341
1342 void nbd_client_put(NBDClient *client)
1343 {
1344 if (--client->refcount == 0) {
1345 /* The last reference should be dropped by client->close,
1346 * which is called by client_close.
1347 */
1348 assert(client->closing);
1349
1350 qio_channel_detach_aio_context(client->ioc);
1351 object_unref(OBJECT(client->sioc));
1352 object_unref(OBJECT(client->ioc));
1353 if (client->tlscreds) {
1354 object_unref(OBJECT(client->tlscreds));
1355 }
1356 g_free(client->tlsaclname);
1357 if (client->exp) {
1358 QTAILQ_REMOVE(&client->exp->clients, client, next);
1359 nbd_export_put(client->exp);
1360 }
1361 g_free(client);
1362 }
1363 }
1364
1365 static void client_close(NBDClient *client, bool negotiated)
1366 {
1367 if (client->closing) {
1368 return;
1369 }
1370
1371 client->closing = true;
1372
1373 /* Force requests to finish. They will drop their own references,
1374 * then we'll close the socket and free the NBDClient.
1375 */
1376 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
1377 NULL);
1378
1379 /* Also tell the client, so that they release their reference. */
1380 if (client->close_fn) {
1381 client->close_fn(client, negotiated);
1382 }
1383 }
1384
1385 static NBDRequestData *nbd_request_get(NBDClient *client)
1386 {
1387 NBDRequestData *req;
1388
1389 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
1390 client->nb_requests++;
1391
1392 req = g_new0(NBDRequestData, 1);
1393 nbd_client_get(client);
1394 req->client = client;
1395 return req;
1396 }
1397
1398 static void nbd_request_put(NBDRequestData *req)
1399 {
1400 NBDClient *client = req->client;
1401
1402 if (req->data) {
1403 qemu_vfree(req->data);
1404 }
1405 g_free(req);
1406
1407 client->nb_requests--;
1408 nbd_client_receive_next_request(client);
1409
1410 nbd_client_put(client);
1411 }
1412
1413 static void blk_aio_attached(AioContext *ctx, void *opaque)
1414 {
1415 NBDExport *exp = opaque;
1416 NBDClient *client;
1417
1418 trace_nbd_blk_aio_attached(exp->name, ctx);
1419
1420 exp->ctx = ctx;
1421
1422 QTAILQ_FOREACH(client, &exp->clients, next) {
1423 qio_channel_attach_aio_context(client->ioc, ctx);
1424 if (client->recv_coroutine) {
1425 aio_co_schedule(ctx, client->recv_coroutine);
1426 }
1427 if (client->send_coroutine) {
1428 aio_co_schedule(ctx, client->send_coroutine);
1429 }
1430 }
1431 }
1432
1433 static void blk_aio_detach(void *opaque)
1434 {
1435 NBDExport *exp = opaque;
1436 NBDClient *client;
1437
1438 trace_nbd_blk_aio_detach(exp->name, exp->ctx);
1439
1440 QTAILQ_FOREACH(client, &exp->clients, next) {
1441 qio_channel_detach_aio_context(client->ioc);
1442 }
1443
1444 exp->ctx = NULL;
1445 }
1446
1447 static void nbd_eject_notifier(Notifier *n, void *data)
1448 {
1449 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1450 nbd_export_close(exp);
1451 }
1452
1453 NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
1454 uint16_t nbdflags, void (*close)(NBDExport *),
1455 bool writethrough, BlockBackend *on_eject_blk,
1456 Error **errp)
1457 {
1458 AioContext *ctx;
1459 BlockBackend *blk;
1460 NBDExport *exp = g_new0(NBDExport, 1);
1461 uint64_t perm;
1462 int ret;
1463
1464 /*
1465 * NBD exports are used for non-shared storage migration. Make sure
1466 * that BDRV_O_INACTIVE is cleared and the image is ready for write
1467 * access since the export could be available before migration handover.
1468 */
1469 ctx = bdrv_get_aio_context(bs);
1470 aio_context_acquire(ctx);
1471 bdrv_invalidate_cache(bs, NULL);
1472 aio_context_release(ctx);
1473
1474 /* Don't allow resize while the NBD server is running, otherwise we don't
1475 * care what happens with the node. */
1476 perm = BLK_PERM_CONSISTENT_READ;
1477 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
1478 perm |= BLK_PERM_WRITE;
1479 }
1480 blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1481 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
1482 ret = blk_insert_bs(blk, bs, errp);
1483 if (ret < 0) {
1484 goto fail;
1485 }
1486 blk_set_enable_write_cache(blk, !writethrough);
1487
1488 exp->refcount = 1;
1489 QTAILQ_INIT(&exp->clients);
1490 exp->blk = blk;
1491 exp->dev_offset = dev_offset;
1492 exp->nbdflags = nbdflags;
1493 exp->size = size < 0 ? blk_getlength(blk) : size;
1494 if (exp->size < 0) {
1495 error_setg_errno(errp, -exp->size,
1496 "Failed to determine the NBD export's length");
1497 goto fail;
1498 }
1499 exp->size -= exp->size % BDRV_SECTOR_SIZE;
1500
1501 exp->close = close;
1502 exp->ctx = blk_get_aio_context(blk);
1503 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1504
1505 if (on_eject_blk) {
1506 blk_ref(on_eject_blk);
1507 exp->eject_notifier_blk = on_eject_blk;
1508 exp->eject_notifier.notify = nbd_eject_notifier;
1509 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1510 }
1511 return exp;
1512
1513 fail:
1514 blk_unref(blk);
1515 g_free(exp);
1516 return NULL;
1517 }
1518
1519 NBDExport *nbd_export_find(const char *name)
1520 {
1521 NBDExport *exp;
1522 QTAILQ_FOREACH(exp, &exports, next) {
1523 if (strcmp(name, exp->name) == 0) {
1524 return exp;
1525 }
1526 }
1527
1528 return NULL;
1529 }
1530
1531 void nbd_export_set_name(NBDExport *exp, const char *name)
1532 {
1533 if (exp->name == name) {
1534 return;
1535 }
1536
1537 nbd_export_get(exp);
1538 if (exp->name != NULL) {
1539 g_free(exp->name);
1540 exp->name = NULL;
1541 QTAILQ_REMOVE(&exports, exp, next);
1542 nbd_export_put(exp);
1543 }
1544 if (name != NULL) {
1545 nbd_export_get(exp);
1546 exp->name = g_strdup(name);
1547 QTAILQ_INSERT_TAIL(&exports, exp, next);
1548 }
1549 nbd_export_put(exp);
1550 }
1551
1552 void nbd_export_set_description(NBDExport *exp, const char *description)
1553 {
1554 g_free(exp->description);
1555 exp->description = g_strdup(description);
1556 }
1557
1558 void nbd_export_close(NBDExport *exp)
1559 {
1560 NBDClient *client, *next;
1561
1562 nbd_export_get(exp);
1563 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1564 client_close(client, true);
1565 }
1566 nbd_export_set_name(exp, NULL);
1567 nbd_export_set_description(exp, NULL);
1568 nbd_export_put(exp);
1569 }
1570
1571 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
1572 {
1573 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
1574 nbd_export_close(exp);
1575 return;
1576 }
1577
1578 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE);
1579
1580 error_setg(errp, "export '%s' still in use", exp->name);
1581 error_append_hint(errp, "Use mode='hard' to force client disconnect\n");
1582 }
1583
1584 void nbd_export_get(NBDExport *exp)
1585 {
1586 assert(exp->refcount > 0);
1587 exp->refcount++;
1588 }
1589
1590 void nbd_export_put(NBDExport *exp)
1591 {
1592 assert(exp->refcount > 0);
1593 if (exp->refcount == 1) {
1594 nbd_export_close(exp);
1595 }
1596
1597 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen
1598 * if someone calls nbd_export_put() on named export not through
1599 * nbd_export_set_name() when refcount is 1. So, let's assert that
1600 * it is > 0.
1601 */
1602 assert(exp->refcount > 0);
1603 if (--exp->refcount == 0) {
1604 assert(exp->name == NULL);
1605 assert(exp->description == NULL);
1606
1607 if (exp->close) {
1608 exp->close(exp);
1609 }
1610
1611 if (exp->blk) {
1612 if (exp->eject_notifier_blk) {
1613 notifier_remove(&exp->eject_notifier);
1614 blk_unref(exp->eject_notifier_blk);
1615 }
1616 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1617 blk_aio_detach, exp);
1618 blk_unref(exp->blk);
1619 exp->blk = NULL;
1620 }
1621
1622 if (exp->export_bitmap) {
1623 bdrv_dirty_bitmap_set_qmp_locked(exp->export_bitmap, false);
1624 g_free(exp->export_bitmap_context);
1625 }
1626
1627 g_free(exp);
1628 }
1629 }
1630
1631 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1632 {
1633 return exp->blk;
1634 }
1635
1636 void nbd_export_close_all(void)
1637 {
1638 NBDExport *exp, *next;
1639
1640 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1641 nbd_export_close(exp);
1642 }
1643 }
1644
1645 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
1646 unsigned niov, Error **errp)
1647 {
1648 int ret;
1649
1650 g_assert(qemu_in_coroutine());
1651 qemu_co_mutex_lock(&client->send_lock);
1652 client->send_coroutine = qemu_coroutine_self();
1653
1654 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
1655
1656 client->send_coroutine = NULL;
1657 qemu_co_mutex_unlock(&client->send_lock);
1658
1659 return ret;
1660 }
1661
1662 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
1663 uint64_t handle)
1664 {
1665 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
1666 stl_be_p(&reply->error, error);
1667 stq_be_p(&reply->handle, handle);
1668 }
1669
1670 static int nbd_co_send_simple_reply(NBDClient *client,
1671 uint64_t handle,
1672 uint32_t error,
1673 void *data,
1674 size_t len,
1675 Error **errp)
1676 {
1677 NBDSimpleReply reply;
1678 int nbd_err = system_errno_to_nbd_errno(error);
1679 struct iovec iov[] = {
1680 {.iov_base = &reply, .iov_len = sizeof(reply)},
1681 {.iov_base = data, .iov_len = len}
1682 };
1683
1684 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
1685 len);
1686 set_be_simple_reply(&reply, nbd_err, handle);
1687
1688 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
1689 }
1690
1691 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,
1692 uint16_t type, uint64_t handle, uint32_t length)
1693 {
1694 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
1695 stw_be_p(&chunk->flags, flags);
1696 stw_be_p(&chunk->type, type);
1697 stq_be_p(&chunk->handle, handle);
1698 stl_be_p(&chunk->length, length);
1699 }
1700
1701 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,
1702 uint64_t handle,
1703 Error **errp)
1704 {
1705 NBDStructuredReplyChunk chunk;
1706 struct iovec iov[] = {
1707 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1708 };
1709
1710 trace_nbd_co_send_structured_done(handle);
1711 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);
1712
1713 return nbd_co_send_iov(client, iov, 1, errp);
1714 }
1715
1716 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,
1717 uint64_t handle,
1718 uint64_t offset,
1719 void *data,
1720 size_t size,
1721 bool final,
1722 Error **errp)
1723 {
1724 NBDStructuredReadData chunk;
1725 struct iovec iov[] = {
1726 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1727 {.iov_base = data, .iov_len = size}
1728 };
1729
1730 assert(size);
1731 trace_nbd_co_send_structured_read(handle, offset, data, size);
1732 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1733 NBD_REPLY_TYPE_OFFSET_DATA, handle,
1734 sizeof(chunk) - sizeof(chunk.h) + size);
1735 stq_be_p(&chunk.offset, offset);
1736
1737 return nbd_co_send_iov(client, iov, 2, errp);
1738 }
1739
1740 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
1741 uint64_t handle,
1742 uint32_t error,
1743 const char *msg,
1744 Error **errp)
1745 {
1746 NBDStructuredError chunk;
1747 int nbd_err = system_errno_to_nbd_errno(error);
1748 struct iovec iov[] = {
1749 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1750 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
1751 };
1752
1753 assert(nbd_err);
1754 trace_nbd_co_send_structured_error(handle, nbd_err,
1755 nbd_err_lookup(nbd_err), msg ? msg : "");
1756 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,
1757 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1758 stl_be_p(&chunk.error, nbd_err);
1759 stw_be_p(&chunk.message_length, iov[1].iov_len);
1760
1761 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);
1762 }
1763
1764 /* Do a sparse read and send the structured reply to the client.
1765 * Returns -errno if sending fails. bdrv_block_status_above() failure is
1766 * reported to the client, at which point this function succeeds.
1767 */
1768 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
1769 uint64_t handle,
1770 uint64_t offset,
1771 uint8_t *data,
1772 size_t size,
1773 Error **errp)
1774 {
1775 int ret = 0;
1776 NBDExport *exp = client->exp;
1777 size_t progress = 0;
1778
1779 while (progress < size) {
1780 int64_t pnum;
1781 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL,
1782 offset + progress,
1783 size - progress, &pnum, NULL,
1784 NULL);
1785 bool final;
1786
1787 if (status < 0) {
1788 char *msg = g_strdup_printf("unable to check for holes: %s",
1789 strerror(-status));
1790
1791 ret = nbd_co_send_structured_error(client, handle, -status, msg,
1792 errp);
1793 g_free(msg);
1794 return ret;
1795 }
1796 assert(pnum && pnum <= size - progress);
1797 final = progress + pnum == size;
1798 if (status & BDRV_BLOCK_ZERO) {
1799 NBDStructuredReadHole chunk;
1800 struct iovec iov[] = {
1801 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1802 };
1803
1804 trace_nbd_co_send_structured_read_hole(handle, offset + progress,
1805 pnum);
1806 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1807 NBD_REPLY_TYPE_OFFSET_HOLE,
1808 handle, sizeof(chunk) - sizeof(chunk.h));
1809 stq_be_p(&chunk.offset, offset + progress);
1810 stl_be_p(&chunk.length, pnum);
1811 ret = nbd_co_send_iov(client, iov, 1, errp);
1812 } else {
1813 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset,
1814 data + progress, pnum);
1815 if (ret < 0) {
1816 error_setg_errno(errp, -ret, "reading from file failed");
1817 break;
1818 }
1819 ret = nbd_co_send_structured_read(client, handle, offset + progress,
1820 data + progress, pnum, final,
1821 errp);
1822 }
1823
1824 if (ret < 0) {
1825 break;
1826 }
1827 progress += pnum;
1828 }
1829 return ret;
1830 }
1831
1832 /*
1833 * Populate @extents from block status. Update @bytes to be the actual
1834 * length encoded (which may be smaller than the original), and update
1835 * @nb_extents to the number of extents used.
1836 *
1837 * Returns zero on success and -errno on bdrv_block_status_above failure.
1838 */
1839 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
1840 uint64_t *bytes, NBDExtent *extents,
1841 unsigned int *nb_extents)
1842 {
1843 uint64_t remaining_bytes = *bytes;
1844 NBDExtent *extent = extents, *extents_end = extents + *nb_extents;
1845 bool first_extent = true;
1846
1847 assert(*nb_extents);
1848 while (remaining_bytes) {
1849 uint32_t flags;
1850 int64_t num;
1851 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes,
1852 &num, NULL, NULL);
1853
1854 if (ret < 0) {
1855 return ret;
1856 }
1857
1858 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |
1859 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
1860 offset += num;
1861 remaining_bytes -= num;
1862
1863 if (first_extent) {
1864 extent->flags = flags;
1865 extent->length = num;
1866 first_extent = false;
1867 continue;
1868 }
1869
1870 if (flags == extent->flags) {
1871 /* extend current extent */
1872 extent->length += num;
1873 } else {
1874 if (extent + 1 == extents_end) {
1875 break;
1876 }
1877
1878 /* start new extent */
1879 extent++;
1880 extent->flags = flags;
1881 extent->length = num;
1882 }
1883 }
1884
1885 extents_end = extent + 1;
1886
1887 for (extent = extents; extent < extents_end; extent++) {
1888 extent->flags = cpu_to_be32(extent->flags);
1889 extent->length = cpu_to_be32(extent->length);
1890 }
1891
1892 *bytes -= remaining_bytes;
1893 *nb_extents = extents_end - extents;
1894
1895 return 0;
1896 }
1897
1898 /* nbd_co_send_extents
1899 *
1900 * @length is only for tracing purposes (and may be smaller or larger
1901 * than the client's original request). @last controls whether
1902 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in
1903 * big-endian format.
1904 */
1905 static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
1906 NBDExtent *extents, unsigned int nb_extents,
1907 uint64_t length, bool last,
1908 uint32_t context_id, Error **errp)
1909 {
1910 NBDStructuredMeta chunk;
1911
1912 struct iovec iov[] = {
1913 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1914 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])}
1915 };
1916
1917 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last);
1918 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0,
1919 NBD_REPLY_TYPE_BLOCK_STATUS,
1920 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1921 stl_be_p(&chunk.context_id, context_id);
1922
1923 return nbd_co_send_iov(client, iov, 2, errp);
1924 }
1925
1926 /* Get block status from the exported device and send it to the client */
1927 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
1928 BlockDriverState *bs, uint64_t offset,
1929 uint32_t length, bool dont_fragment,
1930 bool last, uint32_t context_id,
1931 Error **errp)
1932 {
1933 int ret;
1934 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;
1935 NBDExtent *extents = g_new(NBDExtent, nb_extents);
1936 uint64_t final_length = length;
1937
1938 ret = blockstatus_to_extents(bs, offset, &final_length, extents,
1939 &nb_extents);
1940 if (ret < 0) {
1941 g_free(extents);
1942 return nbd_co_send_structured_error(
1943 client, handle, -ret, "can't get block status", errp);
1944 }
1945
1946 ret = nbd_co_send_extents(client, handle, extents, nb_extents,
1947 final_length, last, context_id, errp);
1948
1949 g_free(extents);
1950
1951 return ret;
1952 }
1953
1954 /*
1955 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the
1956 * final extent may exceed the original @length. Store in @length the
1957 * byte length encoded (which may be smaller or larger than the
1958 * original), and return the number of extents used.
1959 */
1960 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,
1961 uint64_t *length, NBDExtent *extents,
1962 unsigned int nb_extents,
1963 bool dont_fragment)
1964 {
1965 uint64_t begin = offset, end = offset;
1966 uint64_t overall_end = offset + *length;
1967 unsigned int i = 0;
1968 BdrvDirtyBitmapIter *it;
1969 bool dirty;
1970
1971 bdrv_dirty_bitmap_lock(bitmap);
1972
1973 it = bdrv_dirty_iter_new(bitmap);
1974 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset);
1975
1976 assert(begin < overall_end && nb_extents);
1977 while (begin < overall_end && i < nb_extents) {
1978 bool next_dirty = !dirty;
1979
1980 if (dirty) {
1981 end = bdrv_dirty_bitmap_next_zero(bitmap, begin);
1982 } else {
1983 bdrv_set_dirty_iter(it, begin);
1984 end = bdrv_dirty_iter_next(it);
1985 }
1986 if (end == -1 || end - begin > UINT32_MAX) {
1987 /* Cap to an aligned value < 4G beyond begin. */
1988 end = MIN(bdrv_dirty_bitmap_size(bitmap),
1989 begin + UINT32_MAX + 1 -
1990 bdrv_dirty_bitmap_granularity(bitmap));
1991 next_dirty = dirty;
1992 }
1993 if (dont_fragment && end > overall_end) {
1994 end = overall_end;
1995 }
1996
1997 extents[i].length = cpu_to_be32(end - begin);
1998 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0);
1999 i++;
2000 begin = end;
2001 dirty = next_dirty;
2002 }
2003
2004 bdrv_dirty_iter_free(it);
2005
2006 bdrv_dirty_bitmap_unlock(bitmap);
2007
2008 assert(offset < end);
2009 *length = end - offset;
2010 return i;
2011 }
2012
2013 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
2014 BdrvDirtyBitmap *bitmap, uint64_t offset,
2015 uint32_t length, bool dont_fragment, bool last,
2016 uint32_t context_id, Error **errp)
2017 {
2018 int ret;
2019 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;
2020 NBDExtent *extents = g_new(NBDExtent, nb_extents);
2021 uint64_t final_length = length;
2022
2023 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents,
2024 nb_extents, dont_fragment);
2025
2026 ret = nbd_co_send_extents(client, handle, extents, nb_extents,
2027 final_length, last, context_id, errp);
2028
2029 g_free(extents);
2030
2031 return ret;
2032 }
2033
2034 /* nbd_co_receive_request
2035 * Collect a client request. Return 0 if request looks valid, -EIO to drop
2036 * connection right away, and any other negative value to report an error to
2037 * the client (although the caller may still need to disconnect after reporting
2038 * the error).
2039 */
2040 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
2041 Error **errp)
2042 {
2043 NBDClient *client = req->client;
2044 int valid_flags;
2045
2046 g_assert(qemu_in_coroutine());
2047 assert(client->recv_coroutine == qemu_coroutine_self());
2048 if (nbd_receive_request(client->ioc, request, errp) < 0) {
2049 return -EIO;
2050 }
2051
2052 trace_nbd_co_receive_request_decode_type(request->handle, request->type,
2053 nbd_cmd_lookup(request->type));
2054
2055 if (request->type != NBD_CMD_WRITE) {
2056 /* No payload, we are ready to read the next request. */
2057 req->complete = true;
2058 }
2059
2060 if (request->type == NBD_CMD_DISC) {
2061 /* Special case: we're going to disconnect without a reply,
2062 * whether or not flags, from, or len are bogus */
2063 return -EIO;
2064 }
2065
2066 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE ||
2067 request->type == NBD_CMD_CACHE)
2068 {
2069 if (request->len > NBD_MAX_BUFFER_SIZE) {
2070 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
2071 request->len, NBD_MAX_BUFFER_SIZE);
2072 return -EINVAL;
2073 }
2074
2075 req->data = blk_try_blockalign(client->exp->blk, request->len);
2076 if (req->data == NULL) {
2077 error_setg(errp, "No memory");
2078 return -ENOMEM;
2079 }
2080 }
2081 if (request->type == NBD_CMD_WRITE) {
2082 if (nbd_read(client->ioc, req->data, request->len, errp) < 0) {
2083 error_prepend(errp, "reading from socket failed: ");
2084 return -EIO;
2085 }
2086 req->complete = true;
2087
2088 trace_nbd_co_receive_request_payload_received(request->handle,
2089 request->len);
2090 }
2091
2092 /* Sanity checks. */
2093 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY &&
2094 (request->type == NBD_CMD_WRITE ||
2095 request->type == NBD_CMD_WRITE_ZEROES ||
2096 request->type == NBD_CMD_TRIM)) {
2097 error_setg(errp, "Export is read-only");
2098 return -EROFS;
2099 }
2100 if (request->from > client->exp->size ||
2101 request->from + request->len > client->exp->size) {
2102 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
2103 ", Size: %" PRIu64, request->from, request->len,
2104 (uint64_t)client->exp->size);
2105 return (request->type == NBD_CMD_WRITE ||
2106 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
2107 }
2108 valid_flags = NBD_CMD_FLAG_FUA;
2109 if (request->type == NBD_CMD_READ && client->structured_reply) {
2110 valid_flags |= NBD_CMD_FLAG_DF;
2111 } else if (request->type == NBD_CMD_WRITE_ZEROES) {
2112 valid_flags |= NBD_CMD_FLAG_NO_HOLE;
2113 } else if (request->type == NBD_CMD_BLOCK_STATUS) {
2114 valid_flags |= NBD_CMD_FLAG_REQ_ONE;
2115 }
2116 if (request->flags & ~valid_flags) {
2117 error_setg(errp, "unsupported flags for command %s (got 0x%x)",
2118 nbd_cmd_lookup(request->type), request->flags);
2119 return -EINVAL;
2120 }
2121
2122 return 0;
2123 }
2124
2125 /* Send simple reply without a payload, or a structured error
2126 * @error_msg is ignored if @ret >= 0
2127 * Returns 0 if connection is still live, -errno on failure to talk to client
2128 */
2129 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
2130 uint64_t handle,
2131 int ret,
2132 const char *error_msg,
2133 Error **errp)
2134 {
2135 if (client->structured_reply && ret < 0) {
2136 return nbd_co_send_structured_error(client, handle, -ret, error_msg,
2137 errp);
2138 } else {
2139 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,
2140 NULL, 0, errp);
2141 }
2142 }
2143
2144 /* Handle NBD_CMD_READ request.
2145 * Return -errno if sending fails. Other errors are reported directly to the
2146 * client as an error reply. */
2147 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
2148 uint8_t *data, Error **errp)
2149 {
2150 int ret;
2151 NBDExport *exp = client->exp;
2152
2153 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE);
2154
2155 /* XXX: NBD Protocol only documents use of FUA with WRITE */
2156 if (request->flags & NBD_CMD_FLAG_FUA) {
2157 ret = blk_co_flush(exp->blk);
2158 if (ret < 0) {
2159 return nbd_send_generic_reply(client, request->handle, ret,
2160 "flush failed", errp);
2161 }
2162 }
2163
2164 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&
2165 request->len && request->type != NBD_CMD_CACHE)
2166 {
2167 return nbd_co_send_sparse_read(client, request->handle, request->from,
2168 data, request->len, errp);
2169 }
2170
2171 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data,
2172 request->len);
2173 if (ret < 0 || request->type == NBD_CMD_CACHE) {
2174 return nbd_send_generic_reply(client, request->handle, ret,
2175 "reading from file failed", errp);
2176 }
2177
2178 if (client->structured_reply) {
2179 if (request->len) {
2180 return nbd_co_send_structured_read(client, request->handle,
2181 request->from, data,
2182 request->len, true, errp);
2183 } else {
2184 return nbd_co_send_structured_done(client, request->handle, errp);
2185 }
2186 } else {
2187 return nbd_co_send_simple_reply(client, request->handle, 0,
2188 data, request->len, errp);
2189 }
2190 }
2191
2192 /* Handle NBD request.
2193 * Return -errno if sending fails. Other errors are reported directly to the
2194 * client as an error reply. */
2195 static coroutine_fn int nbd_handle_request(NBDClient *client,
2196 NBDRequest *request,
2197 uint8_t *data, Error **errp)
2198 {
2199 int ret;
2200 int flags;
2201 NBDExport *exp = client->exp;
2202 char *msg;
2203
2204 switch (request->type) {
2205 case NBD_CMD_READ:
2206 case NBD_CMD_CACHE:
2207 return nbd_do_cmd_read(client, request, data, errp);
2208
2209 case NBD_CMD_WRITE:
2210 flags = 0;
2211 if (request->flags & NBD_CMD_FLAG_FUA) {
2212 flags |= BDRV_REQ_FUA;
2213 }
2214 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset,
2215 data, request->len, flags);
2216 return nbd_send_generic_reply(client, request->handle, ret,
2217 "writing to file failed", errp);
2218
2219 case NBD_CMD_WRITE_ZEROES:
2220 flags = 0;
2221 if (request->flags & NBD_CMD_FLAG_FUA) {
2222 flags |= BDRV_REQ_FUA;
2223 }
2224 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) {
2225 flags |= BDRV_REQ_MAY_UNMAP;
2226 }
2227 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset,
2228 request->len, flags);
2229 return nbd_send_generic_reply(client, request->handle, ret,
2230 "writing to file failed", errp);
2231
2232 case NBD_CMD_DISC:
2233 /* unreachable, thanks to special case in nbd_co_receive_request() */
2234 abort();
2235
2236 case NBD_CMD_FLUSH:
2237 ret = blk_co_flush(exp->blk);
2238 return nbd_send_generic_reply(client, request->handle, ret,
2239 "flush failed", errp);
2240
2241 case NBD_CMD_TRIM:
2242 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset,
2243 request->len);
2244 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) {
2245 ret = blk_co_flush(exp->blk);
2246 }
2247 return nbd_send_generic_reply(client, request->handle, ret,
2248 "discard failed", errp);
2249
2250 case NBD_CMD_BLOCK_STATUS:
2251 if (!request->len) {
2252 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2253 "need non-zero length", errp);
2254 }
2255 if (client->export_meta.valid &&
2256 (client->export_meta.base_allocation ||
2257 client->export_meta.bitmap))
2258 {
2259 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
2260
2261 if (client->export_meta.base_allocation) {
2262 ret = nbd_co_send_block_status(client, request->handle,
2263 blk_bs(exp->blk), request->from,
2264 request->len, dont_fragment,
2265 !client->export_meta.bitmap,
2266 NBD_META_ID_BASE_ALLOCATION,
2267 errp);
2268 if (ret < 0) {
2269 return ret;
2270 }
2271 }
2272
2273 if (client->export_meta.bitmap) {
2274 ret = nbd_co_send_bitmap(client, request->handle,
2275 client->exp->export_bitmap,
2276 request->from, request->len,
2277 dont_fragment,
2278 true, NBD_META_ID_DIRTY_BITMAP, errp);
2279 if (ret < 0) {
2280 return ret;
2281 }
2282 }
2283
2284 return ret;
2285 } else {
2286 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2287 "CMD_BLOCK_STATUS not negotiated",
2288 errp);
2289 }
2290
2291 default:
2292 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
2293 request->type);
2294 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,
2295 errp);
2296 g_free(msg);
2297 return ret;
2298 }
2299 }
2300
2301 /* Owns a reference to the NBDClient passed as opaque. */
2302 static coroutine_fn void nbd_trip(void *opaque)
2303 {
2304 NBDClient *client = opaque;
2305 NBDRequestData *req;
2306 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
2307 int ret;
2308 Error *local_err = NULL;
2309
2310 trace_nbd_trip();
2311 if (client->closing) {
2312 nbd_client_put(client);
2313 return;
2314 }
2315
2316 req = nbd_request_get(client);
2317 ret = nbd_co_receive_request(req, &request, &local_err);
2318 client->recv_coroutine = NULL;
2319
2320 if (client->closing) {
2321 /*
2322 * The client may be closed when we are blocked in
2323 * nbd_co_receive_request()
2324 */
2325 goto done;
2326 }
2327
2328 nbd_client_receive_next_request(client);
2329 if (ret == -EIO) {
2330 goto disconnect;
2331 }
2332
2333 if (ret < 0) {
2334 /* It wans't -EIO, so, according to nbd_co_receive_request()
2335 * semantics, we should return the error to the client. */
2336 Error *export_err = local_err;
2337
2338 local_err = NULL;
2339 ret = nbd_send_generic_reply(client, request.handle, -EINVAL,
2340 error_get_pretty(export_err), &local_err);
2341 error_free(export_err);
2342 } else {
2343 ret = nbd_handle_request(client, &request, req->data, &local_err);
2344 }
2345 if (ret < 0) {
2346 error_prepend(&local_err, "Failed to send reply: ");
2347 goto disconnect;
2348 }
2349
2350 /* We must disconnect after NBD_CMD_WRITE if we did not
2351 * read the payload.
2352 */
2353 if (!req->complete) {
2354 error_setg(&local_err, "Request handling failed in intermediate state");
2355 goto disconnect;
2356 }
2357
2358 done:
2359 nbd_request_put(req);
2360 nbd_client_put(client);
2361 return;
2362
2363 disconnect:
2364 if (local_err) {
2365 error_reportf_err(local_err, "Disconnect client, due to: ");
2366 }
2367 nbd_request_put(req);
2368 client_close(client, true);
2369 nbd_client_put(client);
2370 }
2371
2372 static void nbd_client_receive_next_request(NBDClient *client)
2373 {
2374 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
2375 nbd_client_get(client);
2376 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
2377 aio_co_schedule(client->exp->ctx, client->recv_coroutine);
2378 }
2379 }
2380
2381 static coroutine_fn void nbd_co_client_start(void *opaque)
2382 {
2383 NBDClient *client = opaque;
2384 Error *local_err = NULL;
2385
2386 qemu_co_mutex_init(&client->send_lock);
2387
2388 if (nbd_negotiate(client, &local_err)) {
2389 if (local_err) {
2390 error_report_err(local_err);
2391 }
2392 client_close(client, false);
2393 return;
2394 }
2395
2396 nbd_client_receive_next_request(client);
2397 }
2398
2399 /*
2400 * Create a new client listener using the given channel @sioc.
2401 * Begin servicing it in a coroutine. When the connection closes, call
2402 * @close_fn with an indication of whether the client completed negotiation.
2403 */
2404 void nbd_client_new(QIOChannelSocket *sioc,
2405 QCryptoTLSCreds *tlscreds,
2406 const char *tlsaclname,
2407 void (*close_fn)(NBDClient *, bool))
2408 {
2409 NBDClient *client;
2410 Coroutine *co;
2411
2412 client = g_new0(NBDClient, 1);
2413 client->refcount = 1;
2414 client->tlscreds = tlscreds;
2415 if (tlscreds) {
2416 object_ref(OBJECT(client->tlscreds));
2417 }
2418 client->tlsaclname = g_strdup(tlsaclname);
2419 client->sioc = sioc;
2420 object_ref(OBJECT(client->sioc));
2421 client->ioc = QIO_CHANNEL(sioc);
2422 object_ref(OBJECT(client->ioc));
2423 client->close_fn = close_fn;
2424
2425 co = qemu_coroutine_create(nbd_co_client_start, client);
2426 qemu_coroutine_enter(co);
2427 }
2428
2429 void nbd_export_bitmap(NBDExport *exp, const char *bitmap,
2430 const char *bitmap_export_name, Error **errp)
2431 {
2432 BdrvDirtyBitmap *bm = NULL;
2433 BlockDriverState *bs = blk_bs(exp->blk);
2434
2435 if (exp->export_bitmap) {
2436 error_setg(errp, "Export bitmap is already set");
2437 return;
2438 }
2439
2440 while (true) {
2441 bm = bdrv_find_dirty_bitmap(bs, bitmap);
2442 if (bm != NULL || bs->backing == NULL) {
2443 break;
2444 }
2445
2446 bs = bs->backing->bs;
2447 }
2448
2449 if (bm == NULL) {
2450 error_setg(errp, "Bitmap '%s' is not found", bitmap);
2451 return;
2452 }
2453
2454 if (bdrv_dirty_bitmap_enabled(bm)) {
2455 error_setg(errp, "Bitmap '%s' is enabled", bitmap);
2456 return;
2457 }
2458
2459 if (bdrv_dirty_bitmap_qmp_locked(bm)) {
2460 error_setg(errp, "Bitmap '%s' is locked", bitmap);
2461 return;
2462 }
2463
2464 bdrv_dirty_bitmap_set_qmp_locked(bm, true);
2465 exp->export_bitmap = bm;
2466 exp->export_bitmap_context =
2467 g_strdup_printf("qemu:dirty-bitmap:%s", bitmap_export_name);
2468 }
armbru's QEMU hackery