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target/ppc: Fix lxvw4x, lxvh8x and lxvb16x
[qemu/ar7.git] / nbd / server.c
blobaeca3893fe2bf3e589f83fd41540db89f75bd984
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 uint64_t dev_offset;
81 uint64_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 *tlsauthz;
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 uint32_t check_align; /* If non-zero, check for aligned client requests */
128
129 bool structured_reply;
130 NBDExportMetaContexts export_meta;
131
132 uint32_t opt; /* Current option being negotiated */
133 uint32_t optlen; /* remaining length of data in ioc for the option being
134 negotiated now */
135 };
136
137 static void nbd_client_receive_next_request(NBDClient *client);
138
139 /* Basic flow for negotiation
140
141 Server Client
142 Negotiate
143
144 or
145
146 Server Client
147 Negotiate #1
148 Option
149 Negotiate #2
150
151 ----
152
153 followed by
154
155 Server Client
156 Request
157 Response
158 Request
159 Response
160 ...
161 ...
162 Request (type == 2)
163
164 */
165
166 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
167 uint32_t type, uint32_t length)
168 {
169 stq_be_p(&rep->magic, NBD_REP_MAGIC);
170 stl_be_p(&rep->option, option);
171 stl_be_p(&rep->type, type);
172 stl_be_p(&rep->length, length);
173 }
174
175 /* Send a reply header, including length, but no payload.
176 * Return -errno on error, 0 on success. */
177 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
178 uint32_t len, Error **errp)
179 {
180 NBDOptionReply rep;
181
182 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),
183 type, nbd_rep_lookup(type), len);
184
185 assert(len < NBD_MAX_BUFFER_SIZE);
186
187 set_be_option_rep(&rep, client->opt, type, len);
188 return nbd_write(client->ioc, &rep, sizeof(rep), errp);
189 }
190
191 /* Send a reply header with default 0 length.
192 * Return -errno on error, 0 on success. */
193 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type,
194 Error **errp)
195 {
196 return nbd_negotiate_send_rep_len(client, type, 0, errp);
197 }
198
199 /* Send an error reply.
200 * Return -errno on error, 0 on success. */
201 static int GCC_FMT_ATTR(4, 0)
202 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
203 Error **errp, const char *fmt, va_list va)
204 {
205 char *msg;
206 int ret;
207 size_t len;
208
209 msg = g_strdup_vprintf(fmt, va);
210 len = strlen(msg);
211 assert(len < 4096);
212 trace_nbd_negotiate_send_rep_err(msg);
213 ret = nbd_negotiate_send_rep_len(client, type, len, errp);
214 if (ret < 0) {
215 goto out;
216 }
217 if (nbd_write(client->ioc, msg, len, errp) < 0) {
218 error_prepend(errp, "write failed (error message): ");
219 ret = -EIO;
220 } else {
221 ret = 0;
222 }
223
224 out:
225 g_free(msg);
226 return ret;
227 }
228
229 /* Send an error reply.
230 * Return -errno on error, 0 on success. */
231 static int GCC_FMT_ATTR(4, 5)
232 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
233 Error **errp, const char *fmt, ...)
234 {
235 va_list va;
236 int ret;
237
238 va_start(va, fmt);
239 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
240 va_end(va);
241 return ret;
242 }
243
244 /* Drop remainder of the current option, and send a reply with the
245 * given error type and message. Return -errno on read or write
246 * failure; or 0 if connection is still live. */
247 static int GCC_FMT_ATTR(4, 0)
248 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
249 const char *fmt, va_list va)
250 {
251 int ret = nbd_drop(client->ioc, client->optlen, errp);
252
253 client->optlen = 0;
254 if (!ret) {
255 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
256 }
257 return ret;
258 }
259
260 static int GCC_FMT_ATTR(4, 5)
261 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
262 const char *fmt, ...)
263 {
264 int ret;
265 va_list va;
266
267 va_start(va, fmt);
268 ret = nbd_opt_vdrop(client, type, errp, fmt, va);
269 va_end(va);
270
271 return ret;
272 }
273
274 static int GCC_FMT_ATTR(3, 4)
275 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
276 {
277 int ret;
278 va_list va;
279
280 va_start(va, fmt);
281 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);
282 va_end(va);
283
284 return ret;
285 }
286
287 /* Read size bytes from the unparsed payload of the current option.
288 * Return -errno on I/O error, 0 if option was completely handled by
289 * sending a reply about inconsistent lengths, or 1 on success. */
290 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
291 Error **errp)
292 {
293 if (size > client->optlen) {
294 return nbd_opt_invalid(client, errp,
295 "Inconsistent lengths in option %s",
296 nbd_opt_lookup(client->opt));
297 }
298 client->optlen -= size;
299 return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1;
300 }
301
302 /* Drop size bytes from the unparsed payload of the current option.
303 * Return -errno on I/O error, 0 if option was completely handled by
304 * sending a reply about inconsistent lengths, or 1 on success. */
305 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
306 {
307 if (size > client->optlen) {
308 return nbd_opt_invalid(client, errp,
309 "Inconsistent lengths in option %s",
310 nbd_opt_lookup(client->opt));
311 }
312 client->optlen -= size;
313 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
314 }
315
316 /* nbd_opt_read_name
317 *
318 * Read a string with the format:
319 * uint32_t len (<= NBD_MAX_NAME_SIZE)
320 * len bytes string (not 0-terminated)
321 *
322 * @name should be enough to store NBD_MAX_NAME_SIZE+1.
323 * If @length is non-null, it will be set to the actual string length.
324 *
325 * Return -errno on I/O error, 0 if option was completely handled by
326 * sending a reply about inconsistent lengths, or 1 on success.
327 */
328 static int nbd_opt_read_name(NBDClient *client, char *name, uint32_t *length,
329 Error **errp)
330 {
331 int ret;
332 uint32_t len;
333
334 ret = nbd_opt_read(client, &len, sizeof(len), errp);
335 if (ret <= 0) {
336 return ret;
337 }
338 len = cpu_to_be32(len);
339
340 if (len > NBD_MAX_NAME_SIZE) {
341 return nbd_opt_invalid(client, errp,
342 "Invalid name length: %" PRIu32, len);
343 }
344
345 ret = nbd_opt_read(client, name, len, errp);
346 if (ret <= 0) {
347 return ret;
348 }
349 name[len] = '\0';
350
351 if (length) {
352 *length = len;
353 }
354
355 return 1;
356 }
357
358 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
359 * Return -errno on error, 0 on success. */
360 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp,
361 Error **errp)
362 {
363 size_t name_len, desc_len;
364 uint32_t len;
365 const char *name = exp->name ? exp->name : "";
366 const char *desc = exp->description ? exp->description : "";
367 QIOChannel *ioc = client->ioc;
368 int ret;
369
370 trace_nbd_negotiate_send_rep_list(name, desc);
371 name_len = strlen(name);
372 desc_len = strlen(desc);
373 len = name_len + desc_len + sizeof(len);
374 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
375 if (ret < 0) {
376 return ret;
377 }
378
379 len = cpu_to_be32(name_len);
380 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
381 error_prepend(errp, "write failed (name length): ");
382 return -EINVAL;
383 }
384
385 if (nbd_write(ioc, name, name_len, errp) < 0) {
386 error_prepend(errp, "write failed (name buffer): ");
387 return -EINVAL;
388 }
389
390 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
391 error_prepend(errp, "write failed (description buffer): ");
392 return -EINVAL;
393 }
394
395 return 0;
396 }
397
398 /* Process the NBD_OPT_LIST command, with a potential series of replies.
399 * Return -errno on error, 0 on success. */
400 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
401 {
402 NBDExport *exp;
403 assert(client->opt == NBD_OPT_LIST);
404
405 /* For each export, send a NBD_REP_SERVER reply. */
406 QTAILQ_FOREACH(exp, &exports, next) {
407 if (nbd_negotiate_send_rep_list(client, exp, errp)) {
408 return -EINVAL;
409 }
410 }
411 /* Finish with a NBD_REP_ACK. */
412 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
413 }
414
415 static void nbd_check_meta_export(NBDClient *client)
416 {
417 client->export_meta.valid &= client->exp == client->export_meta.exp;
418 }
419
420 /* Send a reply to NBD_OPT_EXPORT_NAME.
421 * Return -errno on error, 0 on success. */
422 static int nbd_negotiate_handle_export_name(NBDClient *client,
423 uint16_t myflags, bool no_zeroes,
424 Error **errp)
425 {
426 char name[NBD_MAX_NAME_SIZE + 1];
427 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
428 size_t len;
429 int ret;
430
431 /* Client sends:
432 [20 .. xx] export name (length bytes)
433 Server replies:
434 [ 0 .. 7] size
435 [ 8 .. 9] export flags
436 [10 .. 133] reserved (0) [unless no_zeroes]
437 */
438 trace_nbd_negotiate_handle_export_name();
439 if (client->optlen >= sizeof(name)) {
440 error_setg(errp, "Bad length received");
441 return -EINVAL;
442 }
443 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) {
444 return -EIO;
445 }
446 name[client->optlen] = '\0';
447 client->optlen = 0;
448
449 trace_nbd_negotiate_handle_export_name_request(name);
450
451 client->exp = nbd_export_find(name);
452 if (!client->exp) {
453 error_setg(errp, "export not found");
454 return -EINVAL;
455 }
456
457 trace_nbd_negotiate_new_style_size_flags(client->exp->size,
458 client->exp->nbdflags | myflags);
459 stq_be_p(buf, client->exp->size);
460 stw_be_p(buf + 8, client->exp->nbdflags | myflags);
461 len = no_zeroes ? 10 : sizeof(buf);
462 ret = nbd_write(client->ioc, buf, len, errp);
463 if (ret < 0) {
464 error_prepend(errp, "write failed: ");
465 return ret;
466 }
467
468 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
469 nbd_export_get(client->exp);
470 nbd_check_meta_export(client);
471
472 return 0;
473 }
474
475 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
476 * The buffer does NOT include the info type prefix.
477 * Return -errno on error, 0 if ready to send more. */
478 static int nbd_negotiate_send_info(NBDClient *client,
479 uint16_t info, uint32_t length, void *buf,
480 Error **errp)
481 {
482 int rc;
483
484 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
485 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
486 sizeof(info) + length, errp);
487 if (rc < 0) {
488 return rc;
489 }
490 info = cpu_to_be16(info);
491 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
492 return -EIO;
493 }
494 if (nbd_write(client->ioc, buf, length, errp) < 0) {
495 return -EIO;
496 }
497 return 0;
498 }
499
500 /* nbd_reject_length: Handle any unexpected payload.
501 * @fatal requests that we quit talking to the client, even if we are able
502 * to successfully send an error reply.
503 * Return:
504 * -errno transmission error occurred or @fatal was requested, errp is set
505 * 0 error message successfully sent to client, errp is not set
506 */
507 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
508 {
509 int ret;
510
511 assert(client->optlen);
512 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",
513 nbd_opt_lookup(client->opt));
514 if (fatal && !ret) {
515 error_setg(errp, "option '%s' has unexpected length",
516 nbd_opt_lookup(client->opt));
517 return -EINVAL;
518 }
519 return ret;
520 }
521
522 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
523 * Return -errno on error, 0 if ready for next option, and 1 to move
524 * into transmission phase. */
525 static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
526 Error **errp)
527 {
528 int rc;
529 char name[NBD_MAX_NAME_SIZE + 1];
530 NBDExport *exp;
531 uint16_t requests;
532 uint16_t request;
533 uint32_t namelen;
534 bool sendname = false;
535 bool blocksize = false;
536 uint32_t sizes[3];
537 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
538 uint32_t check_align = 0;
539
540 /* Client sends:
541 4 bytes: L, name length (can be 0)
542 L bytes: export name
543 2 bytes: N, number of requests (can be 0)
544 N * 2 bytes: N requests
545 */
546 rc = nbd_opt_read_name(client, name, &namelen, errp);
547 if (rc <= 0) {
548 return rc;
549 }
550 trace_nbd_negotiate_handle_export_name_request(name);
551
552 rc = nbd_opt_read(client, &requests, sizeof(requests), errp);
553 if (rc <= 0) {
554 return rc;
555 }
556 requests = be16_to_cpu(requests);
557 trace_nbd_negotiate_handle_info_requests(requests);
558 while (requests--) {
559 rc = nbd_opt_read(client, &request, sizeof(request), errp);
560 if (rc <= 0) {
561 return rc;
562 }
563 request = be16_to_cpu(request);
564 trace_nbd_negotiate_handle_info_request(request,
565 nbd_info_lookup(request));
566 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
567 * everything else is either a request we don't know or
568 * something we send regardless of request */
569 switch (request) {
570 case NBD_INFO_NAME:
571 sendname = true;
572 break;
573 case NBD_INFO_BLOCK_SIZE:
574 blocksize = true;
575 break;
576 }
577 }
578 if (client->optlen) {
579 return nbd_reject_length(client, false, errp);
580 }
581
582 exp = nbd_export_find(name);
583 if (!exp) {
584 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
585 errp, "export '%s' not present",
586 name);
587 }
588
589 /* Don't bother sending NBD_INFO_NAME unless client requested it */
590 if (sendname) {
591 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
592 errp);
593 if (rc < 0) {
594 return rc;
595 }
596 }
597
598 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
599 * client request */
600 if (exp->description) {
601 size_t len = strlen(exp->description);
602
603 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
604 len, exp->description, errp);
605 if (rc < 0) {
606 return rc;
607 }
608 }
609
610 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
611 * according to whether the client requested it, and according to
612 * whether this is OPT_INFO or OPT_GO. */
613 /* minimum - 1 for back-compat, or actual if client will obey it. */
614 if (client->opt == NBD_OPT_INFO || blocksize) {
615 check_align = sizes[0] = blk_get_request_alignment(exp->blk);
616 } else {
617 sizes[0] = 1;
618 }
619 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE);
620 /* preferred - Hard-code to 4096 for now.
621 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
622 sizes[1] = MAX(4096, sizes[0]);
623 /* maximum - At most 32M, but smaller as appropriate. */
624 sizes[2] = MIN(blk_get_max_transfer(exp->blk), NBD_MAX_BUFFER_SIZE);
625 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
626 sizes[0] = cpu_to_be32(sizes[0]);
627 sizes[1] = cpu_to_be32(sizes[1]);
628 sizes[2] = cpu_to_be32(sizes[2]);
629 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
630 sizeof(sizes), sizes, errp);
631 if (rc < 0) {
632 return rc;
633 }
634
635 /* Send NBD_INFO_EXPORT always */
636 trace_nbd_negotiate_new_style_size_flags(exp->size,
637 exp->nbdflags | myflags);
638 stq_be_p(buf, exp->size);
639 stw_be_p(buf + 8, exp->nbdflags | myflags);
640 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
641 sizeof(buf), buf, errp);
642 if (rc < 0) {
643 return rc;
644 }
645
646 /*
647 * If the client is just asking for NBD_OPT_INFO, but forgot to
648 * request block sizes in a situation that would impact
649 * performance, then return an error. But for NBD_OPT_GO, we
650 * tolerate all clients, regardless of alignments.
651 */
652 if (client->opt == NBD_OPT_INFO && !blocksize &&
653 blk_get_request_alignment(exp->blk) > 1) {
654 return nbd_negotiate_send_rep_err(client,
655 NBD_REP_ERR_BLOCK_SIZE_REQD,
656 errp,
657 "request NBD_INFO_BLOCK_SIZE to "
658 "use this export");
659 }
660
661 /* Final reply */
662 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
663 if (rc < 0) {
664 return rc;
665 }
666
667 if (client->opt == NBD_OPT_GO) {
668 client->exp = exp;
669 client->check_align = check_align;
670 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
671 nbd_export_get(client->exp);
672 nbd_check_meta_export(client);
673 rc = 1;
674 }
675 return rc;
676 }
677
678
679 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
680 * new channel for all further (now-encrypted) communication. */
681 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
682 Error **errp)
683 {
684 QIOChannel *ioc;
685 QIOChannelTLS *tioc;
686 struct NBDTLSHandshakeData data = { 0 };
687
688 assert(client->opt == NBD_OPT_STARTTLS);
689
690 trace_nbd_negotiate_handle_starttls();
691 ioc = client->ioc;
692
693 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
694 return NULL;
695 }
696
697 tioc = qio_channel_tls_new_server(ioc,
698 client->tlscreds,
699 client->tlsauthz,
700 errp);
701 if (!tioc) {
702 return NULL;
703 }
704
705 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
706 trace_nbd_negotiate_handle_starttls_handshake();
707 data.loop = g_main_loop_new(g_main_context_default(), FALSE);
708 qio_channel_tls_handshake(tioc,
709 nbd_tls_handshake,
710 &data,
711 NULL,
712 NULL);
713
714 if (!data.complete) {
715 g_main_loop_run(data.loop);
716 }
717 g_main_loop_unref(data.loop);
718 if (data.error) {
719 object_unref(OBJECT(tioc));
720 error_propagate(errp, data.error);
721 return NULL;
722 }
723
724 return QIO_CHANNEL(tioc);
725 }
726
727 /* nbd_negotiate_send_meta_context
728 *
729 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
730 *
731 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
732 */
733 static int nbd_negotiate_send_meta_context(NBDClient *client,
734 const char *context,
735 uint32_t context_id,
736 Error **errp)
737 {
738 NBDOptionReplyMetaContext opt;
739 struct iovec iov[] = {
740 {.iov_base = &opt, .iov_len = sizeof(opt)},
741 {.iov_base = (void *)context, .iov_len = strlen(context)}
742 };
743
744 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
745 context_id = 0;
746 }
747
748 trace_nbd_negotiate_meta_query_reply(context, context_id);
749 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
750 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
751 stl_be_p(&opt.context_id, context_id);
752
753 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
754 }
755
756 /* Read strlen(@pattern) bytes, and set @match to true if they match @pattern.
757 * @match is never set to false.
758 *
759 * Return -errno on I/O error, 0 if option was completely handled by
760 * sending a reply about inconsistent lengths, or 1 on success.
761 *
762 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
763 * It only means that there are no errors.
764 */
765 static int nbd_meta_pattern(NBDClient *client, const char *pattern, bool *match,
766 Error **errp)
767 {
768 int ret;
769 char *query;
770 size_t len = strlen(pattern);
771
772 assert(len);
773
774 query = g_malloc(len);
775 ret = nbd_opt_read(client, query, len, errp);
776 if (ret <= 0) {
777 g_free(query);
778 return ret;
779 }
780
781 if (strncmp(query, pattern, len) == 0) {
782 trace_nbd_negotiate_meta_query_parse(pattern);
783 *match = true;
784 } else {
785 trace_nbd_negotiate_meta_query_skip("pattern not matched");
786 }
787 g_free(query);
788
789 return 1;
790 }
791
792 /*
793 * Read @len bytes, and set @match to true if they match @pattern, or if @len
794 * is 0 and the client is performing _LIST_. @match is never set to false.
795 *
796 * Return -errno on I/O error, 0 if option was completely handled by
797 * sending a reply about inconsistent lengths, or 1 on success.
798 *
799 * Note: return code = 1 doesn't mean that we've read exactly @pattern.
800 * It only means that there are no errors.
801 */
802 static int nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
803 uint32_t len, bool *match, Error **errp)
804 {
805 if (len == 0) {
806 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
807 *match = true;
808 }
809 trace_nbd_negotiate_meta_query_parse("empty");
810 return 1;
811 }
812
813 if (len != strlen(pattern)) {
814 trace_nbd_negotiate_meta_query_skip("different lengths");
815 return nbd_opt_skip(client, len, errp);
816 }
817
818 return nbd_meta_pattern(client, pattern, match, errp);
819 }
820
821 /* nbd_meta_base_query
822 *
823 * Handle queries to 'base' namespace. For now, only the base:allocation
824 * context is available. 'len' is the amount of text remaining to be read from
825 * the current name, after the 'base:' portion has been stripped.
826 *
827 * Return -errno on I/O error, 0 if option was completely handled by
828 * sending a reply about inconsistent lengths, or 1 on success.
829 */
830 static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
831 uint32_t len, Error **errp)
832 {
833 return nbd_meta_empty_or_pattern(client, "allocation", len,
834 &meta->base_allocation, errp);
835 }
836
837 /* nbd_meta_bitmap_query
838 *
839 * Handle query to 'qemu:' namespace.
840 * @len is the amount of text remaining to be read from the current name, after
841 * the 'qemu:' portion has been stripped.
842 *
843 * Return -errno on I/O error, 0 if option was completely handled by
844 * sending a reply about inconsistent lengths, or 1 on success. */
845 static int nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
846 uint32_t len, Error **errp)
847 {
848 bool dirty_bitmap = false;
849 size_t dirty_bitmap_len = strlen("dirty-bitmap:");
850 int ret;
851
852 if (!meta->exp->export_bitmap) {
853 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap exported");
854 return nbd_opt_skip(client, len, errp);
855 }
856
857 if (len == 0) {
858 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
859 meta->bitmap = true;
860 }
861 trace_nbd_negotiate_meta_query_parse("empty");
862 return 1;
863 }
864
865 if (len < dirty_bitmap_len) {
866 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
867 return nbd_opt_skip(client, len, errp);
868 }
869
870 len -= dirty_bitmap_len;
871 ret = nbd_meta_pattern(client, "dirty-bitmap:", &dirty_bitmap, errp);
872 if (ret <= 0) {
873 return ret;
874 }
875 if (!dirty_bitmap) {
876 trace_nbd_negotiate_meta_query_skip("not dirty-bitmap:");
877 return nbd_opt_skip(client, len, errp);
878 }
879
880 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
881
882 return nbd_meta_empty_or_pattern(
883 client, meta->exp->export_bitmap_context +
884 strlen("qemu:dirty_bitmap:"), len, &meta->bitmap, errp);
885 }
886
887 /* nbd_negotiate_meta_query
888 *
889 * Parse namespace name and call corresponding function to parse body of the
890 * query.
891 *
892 * The only supported namespace now is 'base'.
893 *
894 * The function aims not wasting time and memory to read long unknown namespace
895 * names.
896 *
897 * Return -errno on I/O error, 0 if option was completely handled by
898 * sending a reply about inconsistent lengths, or 1 on success. */
899 static int nbd_negotiate_meta_query(NBDClient *client,
900 NBDExportMetaContexts *meta, Error **errp)
901 {
902 /*
903 * Both 'qemu' and 'base' namespaces have length = 5 including a
904 * colon. If another length namespace is later introduced, this
905 * should certainly be refactored.
906 */
907 int ret;
908 size_t ns_len = 5;
909 char ns[5];
910 uint32_t len;
911
912 ret = nbd_opt_read(client, &len, sizeof(len), errp);
913 if (ret <= 0) {
914 return ret;
915 }
916 len = cpu_to_be32(len);
917
918 if (len < ns_len) {
919 trace_nbd_negotiate_meta_query_skip("length too short");
920 return nbd_opt_skip(client, len, errp);
921 }
922
923 len -= ns_len;
924 ret = nbd_opt_read(client, ns, ns_len, errp);
925 if (ret <= 0) {
926 return ret;
927 }
928
929 if (!strncmp(ns, "base:", ns_len)) {
930 trace_nbd_negotiate_meta_query_parse("base:");
931 return nbd_meta_base_query(client, meta, len, errp);
932 } else if (!strncmp(ns, "qemu:", ns_len)) {
933 trace_nbd_negotiate_meta_query_parse("qemu:");
934 return nbd_meta_qemu_query(client, meta, len, errp);
935 }
936
937 trace_nbd_negotiate_meta_query_skip("unknown namespace");
938 return nbd_opt_skip(client, len, errp);
939 }
940
941 /* nbd_negotiate_meta_queries
942 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
943 *
944 * Return -errno on I/O error, or 0 if option was completely handled. */
945 static int nbd_negotiate_meta_queries(NBDClient *client,
946 NBDExportMetaContexts *meta, Error **errp)
947 {
948 int ret;
949 char export_name[NBD_MAX_NAME_SIZE + 1];
950 NBDExportMetaContexts local_meta;
951 uint32_t nb_queries;
952 int i;
953
954 if (!client->structured_reply) {
955 return nbd_opt_invalid(client, errp,
956 "request option '%s' when structured reply "
957 "is not negotiated",
958 nbd_opt_lookup(client->opt));
959 }
960
961 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
962 /* Only change the caller's meta on SET. */
963 meta = &local_meta;
964 }
965
966 memset(meta, 0, sizeof(*meta));
967
968 ret = nbd_opt_read_name(client, export_name, NULL, errp);
969 if (ret <= 0) {
970 return ret;
971 }
972
973 meta->exp = nbd_export_find(export_name);
974 if (meta->exp == NULL) {
975 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
976 "export '%s' not present", export_name);
977 }
978
979 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp);
980 if (ret <= 0) {
981 return ret;
982 }
983 nb_queries = cpu_to_be32(nb_queries);
984 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
985 export_name, nb_queries);
986
987 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
988 /* enable all known contexts */
989 meta->base_allocation = true;
990 meta->bitmap = !!meta->exp->export_bitmap;
991 } else {
992 for (i = 0; i < nb_queries; ++i) {
993 ret = nbd_negotiate_meta_query(client, meta, errp);
994 if (ret <= 0) {
995 return ret;
996 }
997 }
998 }
999
1000 if (meta->base_allocation) {
1001 ret = nbd_negotiate_send_meta_context(client, "base:allocation",
1002 NBD_META_ID_BASE_ALLOCATION,
1003 errp);
1004 if (ret < 0) {
1005 return ret;
1006 }
1007 }
1008
1009 if (meta->bitmap) {
1010 ret = nbd_negotiate_send_meta_context(client,
1011 meta->exp->export_bitmap_context,
1012 NBD_META_ID_DIRTY_BITMAP,
1013 errp);
1014 if (ret < 0) {
1015 return ret;
1016 }
1017 }
1018
1019 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1020 if (ret == 0) {
1021 meta->valid = true;
1022 }
1023
1024 return ret;
1025 }
1026
1027 /* nbd_negotiate_options
1028 * Process all NBD_OPT_* client option commands, during fixed newstyle
1029 * negotiation.
1030 * Return:
1031 * -errno on error, errp is set
1032 * 0 on successful negotiation, errp is not set
1033 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1034 * errp is not set
1035 */
1036 static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
1037 Error **errp)
1038 {
1039 uint32_t flags;
1040 bool fixedNewstyle = false;
1041 bool no_zeroes = false;
1042
1043 /* Client sends:
1044 [ 0 .. 3] client flags
1045
1046 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
1047 [ 0 .. 7] NBD_OPTS_MAGIC
1048 [ 8 .. 11] NBD option
1049 [12 .. 15] Data length
1050 ... Rest of request
1051
1052 [ 0 .. 7] NBD_OPTS_MAGIC
1053 [ 8 .. 11] Second NBD option
1054 [12 .. 15] Data length
1055 ... Rest of request
1056 */
1057
1058 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) {
1059 return -EIO;
1060 }
1061 trace_nbd_negotiate_options_flags(flags);
1062 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
1063 fixedNewstyle = true;
1064 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
1065 }
1066 if (flags & NBD_FLAG_C_NO_ZEROES) {
1067 no_zeroes = true;
1068 flags &= ~NBD_FLAG_C_NO_ZEROES;
1069 }
1070 if (flags != 0) {
1071 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
1072 return -EINVAL;
1073 }
1074
1075 while (1) {
1076 int ret;
1077 uint32_t option, length;
1078 uint64_t magic;
1079
1080 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) {
1081 return -EINVAL;
1082 }
1083 trace_nbd_negotiate_options_check_magic(magic);
1084 if (magic != NBD_OPTS_MAGIC) {
1085 error_setg(errp, "Bad magic received");
1086 return -EINVAL;
1087 }
1088
1089 if (nbd_read32(client->ioc, &option, "option", errp) < 0) {
1090 return -EINVAL;
1091 }
1092 client->opt = option;
1093
1094 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) {
1095 return -EINVAL;
1096 }
1097 assert(!client->optlen);
1098 client->optlen = length;
1099
1100 if (length > NBD_MAX_BUFFER_SIZE) {
1101 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
1102 length, NBD_MAX_BUFFER_SIZE);
1103 return -EINVAL;
1104 }
1105
1106 trace_nbd_negotiate_options_check_option(option,
1107 nbd_opt_lookup(option));
1108 if (client->tlscreds &&
1109 client->ioc == (QIOChannel *)client->sioc) {
1110 QIOChannel *tioc;
1111 if (!fixedNewstyle) {
1112 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
1113 return -EINVAL;
1114 }
1115 switch (option) {
1116 case NBD_OPT_STARTTLS:
1117 if (length) {
1118 /* Unconditionally drop the connection if the client
1119 * can't start a TLS negotiation correctly */
1120 return nbd_reject_length(client, true, errp);
1121 }
1122 tioc = nbd_negotiate_handle_starttls(client, errp);
1123 if (!tioc) {
1124 return -EIO;
1125 }
1126 ret = 0;
1127 object_unref(OBJECT(client->ioc));
1128 client->ioc = QIO_CHANNEL(tioc);
1129 break;
1130
1131 case NBD_OPT_EXPORT_NAME:
1132 /* No way to return an error to client, so drop connection */
1133 error_setg(errp, "Option 0x%x not permitted before TLS",
1134 option);
1135 return -EINVAL;
1136
1137 default:
1138 /* Let the client keep trying, unless they asked to
1139 * quit. Always try to give an error back to the
1140 * client; but when replying to OPT_ABORT, be aware
1141 * that the client may hang up before receiving the
1142 * error, in which case we are fine ignoring the
1143 * resulting EPIPE. */
1144 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD,
1145 option == NBD_OPT_ABORT ? NULL : errp,
1146 "Option 0x%" PRIx32
1147 " not permitted before TLS", option);
1148 if (option == NBD_OPT_ABORT) {
1149 return 1;
1150 }
1151 break;
1152 }
1153 } else if (fixedNewstyle) {
1154 switch (option) {
1155 case NBD_OPT_LIST:
1156 if (length) {
1157 ret = nbd_reject_length(client, false, errp);
1158 } else {
1159 ret = nbd_negotiate_handle_list(client, errp);
1160 }
1161 break;
1162
1163 case NBD_OPT_ABORT:
1164 /* NBD spec says we must try to reply before
1165 * disconnecting, but that we must also tolerate
1166 * guests that don't wait for our reply. */
1167 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL);
1168 return 1;
1169
1170 case NBD_OPT_EXPORT_NAME:
1171 return nbd_negotiate_handle_export_name(client,
1172 myflags, no_zeroes,
1173 errp);
1174
1175 case NBD_OPT_INFO:
1176 case NBD_OPT_GO:
1177 ret = nbd_negotiate_handle_info(client, myflags, errp);
1178 if (ret == 1) {
1179 assert(option == NBD_OPT_GO);
1180 return 0;
1181 }
1182 break;
1183
1184 case NBD_OPT_STARTTLS:
1185 if (length) {
1186 ret = nbd_reject_length(client, false, errp);
1187 } else if (client->tlscreds) {
1188 ret = nbd_negotiate_send_rep_err(client,
1189 NBD_REP_ERR_INVALID, errp,
1190 "TLS already enabled");
1191 } else {
1192 ret = nbd_negotiate_send_rep_err(client,
1193 NBD_REP_ERR_POLICY, errp,
1194 "TLS not configured");
1195 }
1196 break;
1197
1198 case NBD_OPT_STRUCTURED_REPLY:
1199 if (length) {
1200 ret = nbd_reject_length(client, false, errp);
1201 } else if (client->structured_reply) {
1202 ret = nbd_negotiate_send_rep_err(
1203 client, NBD_REP_ERR_INVALID, errp,
1204 "structured reply already negotiated");
1205 } else {
1206 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1207 client->structured_reply = true;
1208 myflags |= NBD_FLAG_SEND_DF;
1209 }
1210 break;
1211
1212 case NBD_OPT_LIST_META_CONTEXT:
1213 case NBD_OPT_SET_META_CONTEXT:
1214 ret = nbd_negotiate_meta_queries(client, &client->export_meta,
1215 errp);
1216 break;
1217
1218 default:
1219 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,
1220 "Unsupported option %" PRIu32 " (%s)",
1221 option, nbd_opt_lookup(option));
1222 break;
1223 }
1224 } else {
1225 /*
1226 * If broken new-style we should drop the connection
1227 * for anything except NBD_OPT_EXPORT_NAME
1228 */
1229 switch (option) {
1230 case NBD_OPT_EXPORT_NAME:
1231 return nbd_negotiate_handle_export_name(client,
1232 myflags, no_zeroes,
1233 errp);
1234
1235 default:
1236 error_setg(errp, "Unsupported option %" PRIu32 " (%s)",
1237 option, nbd_opt_lookup(option));
1238 return -EINVAL;
1239 }
1240 }
1241 if (ret < 0) {
1242 return ret;
1243 }
1244 }
1245 }
1246
1247 /* nbd_negotiate
1248 * Return:
1249 * -errno on error, errp is set
1250 * 0 on successful negotiation, errp is not set
1251 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect,
1252 * errp is not set
1253 */
1254 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
1255 {
1256 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
1257 int ret;
1258 const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
1259 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
1260 NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_CACHE);
1261
1262 /* Old style negotiation header, no room for options
1263 [ 0 .. 7] passwd ("NBDMAGIC")
1264 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
1265 [16 .. 23] size
1266 [24 .. 27] export flags (zero-extended)
1267 [28 .. 151] reserved (0)
1268
1269 New style negotiation header, client can send options
1270 [ 0 .. 7] passwd ("NBDMAGIC")
1271 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
1272 [16 .. 17] server flags (0)
1273 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
1274 */
1275
1276 qio_channel_set_blocking(client->ioc, false, NULL);
1277
1278 trace_nbd_negotiate_begin();
1279 memcpy(buf, "NBDMAGIC", 8);
1280
1281 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
1282 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
1283
1284 if (nbd_write(client->ioc, buf, 18, errp) < 0) {
1285 error_prepend(errp, "write failed: ");
1286 return -EINVAL;
1287 }
1288 ret = nbd_negotiate_options(client, myflags, errp);
1289 if (ret != 0) {
1290 if (ret < 0) {
1291 error_prepend(errp, "option negotiation failed: ");
1292 }
1293 return ret;
1294 }
1295
1296 assert(!client->optlen);
1297 trace_nbd_negotiate_success();
1298
1299 return 0;
1300 }
1301
1302 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
1303 Error **errp)
1304 {
1305 uint8_t buf[NBD_REQUEST_SIZE];
1306 uint32_t magic;
1307 int ret;
1308
1309 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp);
1310 if (ret < 0) {
1311 return ret;
1312 }
1313
1314 /* Request
1315 [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
1316 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
1317 [ 6 .. 7] type (NBD_CMD_READ, ...)
1318 [ 8 .. 15] handle
1319 [16 .. 23] from
1320 [24 .. 27] len
1321 */
1322
1323 magic = ldl_be_p(buf);
1324 request->flags = lduw_be_p(buf + 4);
1325 request->type = lduw_be_p(buf + 6);
1326 request->handle = ldq_be_p(buf + 8);
1327 request->from = ldq_be_p(buf + 16);
1328 request->len = ldl_be_p(buf + 24);
1329
1330 trace_nbd_receive_request(magic, request->flags, request->type,
1331 request->from, request->len);
1332
1333 if (magic != NBD_REQUEST_MAGIC) {
1334 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic);
1335 return -EINVAL;
1336 }
1337 return 0;
1338 }
1339
1340 #define MAX_NBD_REQUESTS 16
1341
1342 void nbd_client_get(NBDClient *client)
1343 {
1344 client->refcount++;
1345 }
1346
1347 void nbd_client_put(NBDClient *client)
1348 {
1349 if (--client->refcount == 0) {
1350 /* The last reference should be dropped by client->close,
1351 * which is called by client_close.
1352 */
1353 assert(client->closing);
1354
1355 qio_channel_detach_aio_context(client->ioc);
1356 object_unref(OBJECT(client->sioc));
1357 object_unref(OBJECT(client->ioc));
1358 if (client->tlscreds) {
1359 object_unref(OBJECT(client->tlscreds));
1360 }
1361 g_free(client->tlsauthz);
1362 if (client->exp) {
1363 QTAILQ_REMOVE(&client->exp->clients, client, next);
1364 nbd_export_put(client->exp);
1365 }
1366 g_free(client);
1367 }
1368 }
1369
1370 static void client_close(NBDClient *client, bool negotiated)
1371 {
1372 if (client->closing) {
1373 return;
1374 }
1375
1376 client->closing = true;
1377
1378 /* Force requests to finish. They will drop their own references,
1379 * then we'll close the socket and free the NBDClient.
1380 */
1381 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
1382 NULL);
1383
1384 /* Also tell the client, so that they release their reference. */
1385 if (client->close_fn) {
1386 client->close_fn(client, negotiated);
1387 }
1388 }
1389
1390 static NBDRequestData *nbd_request_get(NBDClient *client)
1391 {
1392 NBDRequestData *req;
1393
1394 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
1395 client->nb_requests++;
1396
1397 req = g_new0(NBDRequestData, 1);
1398 nbd_client_get(client);
1399 req->client = client;
1400 return req;
1401 }
1402
1403 static void nbd_request_put(NBDRequestData *req)
1404 {
1405 NBDClient *client = req->client;
1406
1407 if (req->data) {
1408 qemu_vfree(req->data);
1409 }
1410 g_free(req);
1411
1412 client->nb_requests--;
1413 nbd_client_receive_next_request(client);
1414
1415 nbd_client_put(client);
1416 }
1417
1418 static void blk_aio_attached(AioContext *ctx, void *opaque)
1419 {
1420 NBDExport *exp = opaque;
1421 NBDClient *client;
1422
1423 trace_nbd_blk_aio_attached(exp->name, ctx);
1424
1425 exp->ctx = ctx;
1426
1427 QTAILQ_FOREACH(client, &exp->clients, next) {
1428 qio_channel_attach_aio_context(client->ioc, ctx);
1429 if (client->recv_coroutine) {
1430 aio_co_schedule(ctx, client->recv_coroutine);
1431 }
1432 if (client->send_coroutine) {
1433 aio_co_schedule(ctx, client->send_coroutine);
1434 }
1435 }
1436 }
1437
1438 static void blk_aio_detach(void *opaque)
1439 {
1440 NBDExport *exp = opaque;
1441 NBDClient *client;
1442
1443 trace_nbd_blk_aio_detach(exp->name, exp->ctx);
1444
1445 QTAILQ_FOREACH(client, &exp->clients, next) {
1446 qio_channel_detach_aio_context(client->ioc);
1447 }
1448
1449 exp->ctx = NULL;
1450 }
1451
1452 static void nbd_eject_notifier(Notifier *n, void *data)
1453 {
1454 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1455 nbd_export_close(exp);
1456 }
1457
1458 NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
1459 uint64_t size, const char *name, const char *desc,
1460 const char *bitmap, uint16_t nbdflags,
1461 void (*close)(NBDExport *), bool writethrough,
1462 BlockBackend *on_eject_blk, Error **errp)
1463 {
1464 AioContext *ctx;
1465 BlockBackend *blk;
1466 NBDExport *exp = g_new0(NBDExport, 1);
1467 uint64_t perm;
1468 int ret;
1469
1470 /*
1471 * NBD exports are used for non-shared storage migration. Make sure
1472 * that BDRV_O_INACTIVE is cleared and the image is ready for write
1473 * access since the export could be available before migration handover.
1474 */
1475 assert(name);
1476 ctx = bdrv_get_aio_context(bs);
1477 aio_context_acquire(ctx);
1478 bdrv_invalidate_cache(bs, NULL);
1479 aio_context_release(ctx);
1480
1481 /* Don't allow resize while the NBD server is running, otherwise we don't
1482 * care what happens with the node. */
1483 perm = BLK_PERM_CONSISTENT_READ;
1484 if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) {
1485 perm |= BLK_PERM_WRITE;
1486 }
1487 blk = blk_new(bdrv_get_aio_context(bs), perm,
1488 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
1489 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD);
1490 ret = blk_insert_bs(blk, bs, errp);
1491 if (ret < 0) {
1492 goto fail;
1493 }
1494 blk_set_enable_write_cache(blk, !writethrough);
1495 blk_set_allow_aio_context_change(blk, true);
1496
1497 exp->refcount = 1;
1498 QTAILQ_INIT(&exp->clients);
1499 exp->blk = blk;
1500 assert(dev_offset <= INT64_MAX);
1501 exp->dev_offset = dev_offset;
1502 exp->name = g_strdup(name);
1503 exp->description = g_strdup(desc);
1504 exp->nbdflags = nbdflags;
1505 assert(size <= INT64_MAX - dev_offset);
1506 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
1507
1508 if (bitmap) {
1509 BdrvDirtyBitmap *bm = NULL;
1510
1511 while (true) {
1512 bm = bdrv_find_dirty_bitmap(bs, bitmap);
1513 if (bm != NULL || bs->backing == NULL) {
1514 break;
1515 }
1516
1517 bs = bs->backing->bs;
1518 }
1519
1520 if (bm == NULL) {
1521 error_setg(errp, "Bitmap '%s' is not found", bitmap);
1522 goto fail;
1523 }
1524
1525 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
1526 goto fail;
1527 }
1528
1529 if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&
1530 bdrv_dirty_bitmap_enabled(bm)) {
1531 error_setg(errp,
1532 "Enabled bitmap '%s' incompatible with readonly export",
1533 bitmap);
1534 goto fail;
1535 }
1536
1537 bdrv_dirty_bitmap_set_busy(bm, true);
1538 exp->export_bitmap = bm;
1539 exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s",
1540 bitmap);
1541 }
1542
1543 exp->close = close;
1544 exp->ctx = blk_get_aio_context(blk);
1545 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1546
1547 if (on_eject_blk) {
1548 blk_ref(on_eject_blk);
1549 exp->eject_notifier_blk = on_eject_blk;
1550 exp->eject_notifier.notify = nbd_eject_notifier;
1551 blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
1552 }
1553 QTAILQ_INSERT_TAIL(&exports, exp, next);
1554 nbd_export_get(exp);
1555 return exp;
1556
1557 fail:
1558 blk_unref(blk);
1559 g_free(exp->name);
1560 g_free(exp->description);
1561 g_free(exp);
1562 return NULL;
1563 }
1564
1565 NBDExport *nbd_export_find(const char *name)
1566 {
1567 NBDExport *exp;
1568 QTAILQ_FOREACH(exp, &exports, next) {
1569 if (strcmp(name, exp->name) == 0) {
1570 return exp;
1571 }
1572 }
1573
1574 return NULL;
1575 }
1576
1577 void nbd_export_close(NBDExport *exp)
1578 {
1579 NBDClient *client, *next;
1580
1581 nbd_export_get(exp);
1582 /*
1583 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a
1584 * close mode that stops advertising the export to new clients but
1585 * still permits existing clients to run to completion? Because of
1586 * that possibility, nbd_export_close() can be called more than
1587 * once on an export.
1588 */
1589 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1590 client_close(client, true);
1591 }
1592 if (exp->name) {
1593 nbd_export_put(exp);
1594 g_free(exp->name);
1595 exp->name = NULL;
1596 QTAILQ_REMOVE(&exports, exp, next);
1597 }
1598 g_free(exp->description);
1599 exp->description = NULL;
1600 nbd_export_put(exp);
1601 }
1602
1603 void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp)
1604 {
1605 if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) {
1606 nbd_export_close(exp);
1607 return;
1608 }
1609
1610 assert(mode == NBD_SERVER_REMOVE_MODE_SAFE);
1611
1612 error_setg(errp, "export '%s' still in use", exp->name);
1613 error_append_hint(errp, "Use mode='hard' to force client disconnect\n");
1614 }
1615
1616 void nbd_export_get(NBDExport *exp)
1617 {
1618 assert(exp->refcount > 0);
1619 exp->refcount++;
1620 }
1621
1622 void nbd_export_put(NBDExport *exp)
1623 {
1624 assert(exp->refcount > 0);
1625 if (exp->refcount == 1) {
1626 nbd_export_close(exp);
1627 }
1628
1629 /* nbd_export_close() may theoretically reduce refcount to 0. It may happen
1630 * if someone calls nbd_export_put() on named export not through
1631 * nbd_export_set_name() when refcount is 1. So, let's assert that
1632 * it is > 0.
1633 */
1634 assert(exp->refcount > 0);
1635 if (--exp->refcount == 0) {
1636 assert(exp->name == NULL);
1637 assert(exp->description == NULL);
1638
1639 if (exp->close) {
1640 exp->close(exp);
1641 }
1642
1643 if (exp->blk) {
1644 if (exp->eject_notifier_blk) {
1645 notifier_remove(&exp->eject_notifier);
1646 blk_unref(exp->eject_notifier_blk);
1647 }
1648 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
1649 blk_aio_detach, exp);
1650 blk_unref(exp->blk);
1651 exp->blk = NULL;
1652 }
1653
1654 if (exp->export_bitmap) {
1655 bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false);
1656 g_free(exp->export_bitmap_context);
1657 }
1658
1659 g_free(exp);
1660 }
1661 }
1662
1663 BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
1664 {
1665 return exp->blk;
1666 }
1667
1668 void nbd_export_close_all(void)
1669 {
1670 NBDExport *exp, *next;
1671
1672 QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
1673 nbd_export_close(exp);
1674 }
1675 }
1676
1677 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
1678 unsigned niov, Error **errp)
1679 {
1680 int ret;
1681
1682 g_assert(qemu_in_coroutine());
1683 qemu_co_mutex_lock(&client->send_lock);
1684 client->send_coroutine = qemu_coroutine_self();
1685
1686 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
1687
1688 client->send_coroutine = NULL;
1689 qemu_co_mutex_unlock(&client->send_lock);
1690
1691 return ret;
1692 }
1693
1694 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
1695 uint64_t handle)
1696 {
1697 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
1698 stl_be_p(&reply->error, error);
1699 stq_be_p(&reply->handle, handle);
1700 }
1701
1702 static int nbd_co_send_simple_reply(NBDClient *client,
1703 uint64_t handle,
1704 uint32_t error,
1705 void *data,
1706 size_t len,
1707 Error **errp)
1708 {
1709 NBDSimpleReply reply;
1710 int nbd_err = system_errno_to_nbd_errno(error);
1711 struct iovec iov[] = {
1712 {.iov_base = &reply, .iov_len = sizeof(reply)},
1713 {.iov_base = data, .iov_len = len}
1714 };
1715
1716 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
1717 len);
1718 set_be_simple_reply(&reply, nbd_err, handle);
1719
1720 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp);
1721 }
1722
1723 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags,
1724 uint16_t type, uint64_t handle, uint32_t length)
1725 {
1726 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
1727 stw_be_p(&chunk->flags, flags);
1728 stw_be_p(&chunk->type, type);
1729 stq_be_p(&chunk->handle, handle);
1730 stl_be_p(&chunk->length, length);
1731 }
1732
1733 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client,
1734 uint64_t handle,
1735 Error **errp)
1736 {
1737 NBDStructuredReplyChunk chunk;
1738 struct iovec iov[] = {
1739 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1740 };
1741
1742 trace_nbd_co_send_structured_done(handle);
1743 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0);
1744
1745 return nbd_co_send_iov(client, iov, 1, errp);
1746 }
1747
1748 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client,
1749 uint64_t handle,
1750 uint64_t offset,
1751 void *data,
1752 size_t size,
1753 bool final,
1754 Error **errp)
1755 {
1756 NBDStructuredReadData chunk;
1757 struct iovec iov[] = {
1758 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1759 {.iov_base = data, .iov_len = size}
1760 };
1761
1762 assert(size);
1763 trace_nbd_co_send_structured_read(handle, offset, data, size);
1764 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1765 NBD_REPLY_TYPE_OFFSET_DATA, handle,
1766 sizeof(chunk) - sizeof(chunk.h) + size);
1767 stq_be_p(&chunk.offset, offset);
1768
1769 return nbd_co_send_iov(client, iov, 2, errp);
1770 }
1771
1772 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
1773 uint64_t handle,
1774 uint32_t error,
1775 const char *msg,
1776 Error **errp)
1777 {
1778 NBDStructuredError chunk;
1779 int nbd_err = system_errno_to_nbd_errno(error);
1780 struct iovec iov[] = {
1781 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1782 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
1783 };
1784
1785 assert(nbd_err);
1786 trace_nbd_co_send_structured_error(handle, nbd_err,
1787 nbd_err_lookup(nbd_err), msg ? msg : "");
1788 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,
1789 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1790 stl_be_p(&chunk.error, nbd_err);
1791 stw_be_p(&chunk.message_length, iov[1].iov_len);
1792
1793 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);
1794 }
1795
1796 /* Do a sparse read and send the structured reply to the client.
1797 * Returns -errno if sending fails. bdrv_block_status_above() failure is
1798 * reported to the client, at which point this function succeeds.
1799 */
1800 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
1801 uint64_t handle,
1802 uint64_t offset,
1803 uint8_t *data,
1804 size_t size,
1805 Error **errp)
1806 {
1807 int ret = 0;
1808 NBDExport *exp = client->exp;
1809 size_t progress = 0;
1810
1811 while (progress < size) {
1812 int64_t pnum;
1813 int status = bdrv_block_status_above(blk_bs(exp->blk), NULL,
1814 offset + progress,
1815 size - progress, &pnum, NULL,
1816 NULL);
1817 bool final;
1818
1819 if (status < 0) {
1820 char *msg = g_strdup_printf("unable to check for holes: %s",
1821 strerror(-status));
1822
1823 ret = nbd_co_send_structured_error(client, handle, -status, msg,
1824 errp);
1825 g_free(msg);
1826 return ret;
1827 }
1828 assert(pnum && pnum <= size - progress);
1829 final = progress + pnum == size;
1830 if (status & BDRV_BLOCK_ZERO) {
1831 NBDStructuredReadHole chunk;
1832 struct iovec iov[] = {
1833 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1834 };
1835
1836 trace_nbd_co_send_structured_read_hole(handle, offset + progress,
1837 pnum);
1838 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0,
1839 NBD_REPLY_TYPE_OFFSET_HOLE,
1840 handle, sizeof(chunk) - sizeof(chunk.h));
1841 stq_be_p(&chunk.offset, offset + progress);
1842 stl_be_p(&chunk.length, pnum);
1843 ret = nbd_co_send_iov(client, iov, 1, errp);
1844 } else {
1845 ret = blk_pread(exp->blk, offset + progress + exp->dev_offset,
1846 data + progress, pnum);
1847 if (ret < 0) {
1848 error_setg_errno(errp, -ret, "reading from file failed");
1849 break;
1850 }
1851 ret = nbd_co_send_structured_read(client, handle, offset + progress,
1852 data + progress, pnum, final,
1853 errp);
1854 }
1855
1856 if (ret < 0) {
1857 break;
1858 }
1859 progress += pnum;
1860 }
1861 return ret;
1862 }
1863
1864 /*
1865 * Populate @extents from block status. Update @bytes to be the actual
1866 * length encoded (which may be smaller than the original), and update
1867 * @nb_extents to the number of extents used.
1868 *
1869 * Returns zero on success and -errno on bdrv_block_status_above failure.
1870 */
1871 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
1872 uint64_t *bytes, NBDExtent *extents,
1873 unsigned int *nb_extents)
1874 {
1875 uint64_t remaining_bytes = *bytes;
1876 NBDExtent *extent = extents, *extents_end = extents + *nb_extents;
1877 bool first_extent = true;
1878
1879 assert(*nb_extents);
1880 while (remaining_bytes) {
1881 uint32_t flags;
1882 int64_t num;
1883 int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes,
1884 &num, NULL, NULL);
1885
1886 if (ret < 0) {
1887 return ret;
1888 }
1889
1890 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |
1891 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
1892
1893 if (first_extent) {
1894 extent->flags = flags;
1895 extent->length = num;
1896 first_extent = false;
1897 } else if (flags == extent->flags) {
1898 /* extend current extent */
1899 extent->length += num;
1900 } else {
1901 if (extent + 1 == extents_end) {
1902 break;
1903 }
1904
1905 /* start new extent */
1906 extent++;
1907 extent->flags = flags;
1908 extent->length = num;
1909 }
1910 offset += num;
1911 remaining_bytes -= num;
1912 }
1913
1914 extents_end = extent + 1;
1915
1916 for (extent = extents; extent < extents_end; extent++) {
1917 extent->flags = cpu_to_be32(extent->flags);
1918 extent->length = cpu_to_be32(extent->length);
1919 }
1920
1921 *bytes -= remaining_bytes;
1922 *nb_extents = extents_end - extents;
1923
1924 return 0;
1925 }
1926
1927 /* nbd_co_send_extents
1928 *
1929 * @length is only for tracing purposes (and may be smaller or larger
1930 * than the client's original request). @last controls whether
1931 * NBD_REPLY_FLAG_DONE is sent. @extents should already be in
1932 * big-endian format.
1933 */
1934 static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
1935 NBDExtent *extents, unsigned int nb_extents,
1936 uint64_t length, bool last,
1937 uint32_t context_id, Error **errp)
1938 {
1939 NBDStructuredMeta chunk;
1940
1941 struct iovec iov[] = {
1942 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
1943 {.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])}
1944 };
1945
1946 trace_nbd_co_send_extents(handle, nb_extents, context_id, length, last);
1947 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0,
1948 NBD_REPLY_TYPE_BLOCK_STATUS,
1949 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
1950 stl_be_p(&chunk.context_id, context_id);
1951
1952 return nbd_co_send_iov(client, iov, 2, errp);
1953 }
1954
1955 /* Get block status from the exported device and send it to the client */
1956 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
1957 BlockDriverState *bs, uint64_t offset,
1958 uint32_t length, bool dont_fragment,
1959 bool last, uint32_t context_id,
1960 Error **errp)
1961 {
1962 int ret;
1963 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;
1964 NBDExtent *extents = g_new(NBDExtent, nb_extents);
1965 uint64_t final_length = length;
1966
1967 ret = blockstatus_to_extents(bs, offset, &final_length, extents,
1968 &nb_extents);
1969 if (ret < 0) {
1970 g_free(extents);
1971 return nbd_co_send_structured_error(
1972 client, handle, -ret, "can't get block status", errp);
1973 }
1974
1975 ret = nbd_co_send_extents(client, handle, extents, nb_extents,
1976 final_length, last, context_id, errp);
1977
1978 g_free(extents);
1979
1980 return ret;
1981 }
1982
1983 /*
1984 * Populate @extents from a dirty bitmap. Unless @dont_fragment, the
1985 * final extent may exceed the original @length. Store in @length the
1986 * byte length encoded (which may be smaller or larger than the
1987 * original), and return the number of extents used.
1988 */
1989 static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,
1990 uint64_t *length, NBDExtent *extents,
1991 unsigned int nb_extents,
1992 bool dont_fragment)
1993 {
1994 uint64_t begin = offset, end = offset;
1995 uint64_t overall_end = offset + *length;
1996 unsigned int i = 0;
1997 BdrvDirtyBitmapIter *it;
1998 bool dirty;
1999
2000 bdrv_dirty_bitmap_lock(bitmap);
2001
2002 it = bdrv_dirty_iter_new(bitmap);
2003 dirty = bdrv_get_dirty_locked(NULL, bitmap, offset);
2004
2005 assert(begin < overall_end && nb_extents);
2006 while (begin < overall_end && i < nb_extents) {
2007 bool next_dirty = !dirty;
2008
2009 if (dirty) {
2010 end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX);
2011 } else {
2012 bdrv_set_dirty_iter(it, begin);
2013 end = bdrv_dirty_iter_next(it);
2014 }
2015 if (end == -1 || end - begin > UINT32_MAX) {
2016 /* Cap to an aligned value < 4G beyond begin. */
2017 end = MIN(bdrv_dirty_bitmap_size(bitmap),
2018 begin + UINT32_MAX + 1 -
2019 bdrv_dirty_bitmap_granularity(bitmap));
2020 next_dirty = dirty;
2021 }
2022 if (dont_fragment && end > overall_end) {
2023 end = overall_end;
2024 }
2025
2026 extents[i].length = cpu_to_be32(end - begin);
2027 extents[i].flags = cpu_to_be32(dirty ? NBD_STATE_DIRTY : 0);
2028 i++;
2029 begin = end;
2030 dirty = next_dirty;
2031 }
2032
2033 bdrv_dirty_iter_free(it);
2034
2035 bdrv_dirty_bitmap_unlock(bitmap);
2036
2037 assert(offset < end);
2038 *length = end - offset;
2039 return i;
2040 }
2041
2042 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
2043 BdrvDirtyBitmap *bitmap, uint64_t offset,
2044 uint32_t length, bool dont_fragment, bool last,
2045 uint32_t context_id, Error **errp)
2046 {
2047 int ret;
2048 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS;
2049 NBDExtent *extents = g_new(NBDExtent, nb_extents);
2050 uint64_t final_length = length;
2051
2052 nb_extents = bitmap_to_extents(bitmap, offset, &final_length, extents,
2053 nb_extents, dont_fragment);
2054
2055 ret = nbd_co_send_extents(client, handle, extents, nb_extents,
2056 final_length, last, context_id, errp);
2057
2058 g_free(extents);
2059
2060 return ret;
2061 }
2062
2063 /* nbd_co_receive_request
2064 * Collect a client request. Return 0 if request looks valid, -EIO to drop
2065 * connection right away, and any other negative value to report an error to
2066 * the client (although the caller may still need to disconnect after reporting
2067 * the error).
2068 */
2069 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
2070 Error **errp)
2071 {
2072 NBDClient *client = req->client;
2073 int valid_flags;
2074
2075 g_assert(qemu_in_coroutine());
2076 assert(client->recv_coroutine == qemu_coroutine_self());
2077 if (nbd_receive_request(client->ioc, request, errp) < 0) {
2078 return -EIO;
2079 }
2080
2081 trace_nbd_co_receive_request_decode_type(request->handle, request->type,
2082 nbd_cmd_lookup(request->type));
2083
2084 if (request->type != NBD_CMD_WRITE) {
2085 /* No payload, we are ready to read the next request. */
2086 req->complete = true;
2087 }
2088
2089 if (request->type == NBD_CMD_DISC) {
2090 /* Special case: we're going to disconnect without a reply,
2091 * whether or not flags, from, or len are bogus */
2092 return -EIO;
2093 }
2094
2095 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE ||
2096 request->type == NBD_CMD_CACHE)
2097 {
2098 if (request->len > NBD_MAX_BUFFER_SIZE) {
2099 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
2100 request->len, NBD_MAX_BUFFER_SIZE);
2101 return -EINVAL;
2102 }
2103
2104 req->data = blk_try_blockalign(client->exp->blk, request->len);
2105 if (req->data == NULL) {
2106 error_setg(errp, "No memory");
2107 return -ENOMEM;
2108 }
2109 }
2110 if (request->type == NBD_CMD_WRITE) {
2111 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data",
2112 errp) < 0)
2113 {
2114 return -EIO;
2115 }
2116 req->complete = true;
2117
2118 trace_nbd_co_receive_request_payload_received(request->handle,
2119 request->len);
2120 }
2121
2122 /* Sanity checks. */
2123 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY &&
2124 (request->type == NBD_CMD_WRITE ||
2125 request->type == NBD_CMD_WRITE_ZEROES ||
2126 request->type == NBD_CMD_TRIM)) {
2127 error_setg(errp, "Export is read-only");
2128 return -EROFS;
2129 }
2130 if (request->from > client->exp->size ||
2131 request->len > client->exp->size - request->from) {
2132 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
2133 ", Size: %" PRIu64, request->from, request->len,
2134 client->exp->size);
2135 return (request->type == NBD_CMD_WRITE ||
2136 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
2137 }
2138 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len,
2139 client->check_align)) {
2140 /*
2141 * The block layer gracefully handles unaligned requests, but
2142 * it's still worth tracing client non-compliance
2143 */
2144 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type),
2145 request->from,
2146 request->len,
2147 client->check_align);
2148 }
2149 valid_flags = NBD_CMD_FLAG_FUA;
2150 if (request->type == NBD_CMD_READ && client->structured_reply) {
2151 valid_flags |= NBD_CMD_FLAG_DF;
2152 } else if (request->type == NBD_CMD_WRITE_ZEROES) {
2153 valid_flags |= NBD_CMD_FLAG_NO_HOLE;
2154 } else if (request->type == NBD_CMD_BLOCK_STATUS) {
2155 valid_flags |= NBD_CMD_FLAG_REQ_ONE;
2156 }
2157 if (request->flags & ~valid_flags) {
2158 error_setg(errp, "unsupported flags for command %s (got 0x%x)",
2159 nbd_cmd_lookup(request->type), request->flags);
2160 return -EINVAL;
2161 }
2162
2163 return 0;
2164 }
2165
2166 /* Send simple reply without a payload, or a structured error
2167 * @error_msg is ignored if @ret >= 0
2168 * Returns 0 if connection is still live, -errno on failure to talk to client
2169 */
2170 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
2171 uint64_t handle,
2172 int ret,
2173 const char *error_msg,
2174 Error **errp)
2175 {
2176 if (client->structured_reply && ret < 0) {
2177 return nbd_co_send_structured_error(client, handle, -ret, error_msg,
2178 errp);
2179 } else {
2180 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,
2181 NULL, 0, errp);
2182 }
2183 }
2184
2185 /* Handle NBD_CMD_READ request.
2186 * Return -errno if sending fails. Other errors are reported directly to the
2187 * client as an error reply. */
2188 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
2189 uint8_t *data, Error **errp)
2190 {
2191 int ret;
2192 NBDExport *exp = client->exp;
2193
2194 assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE);
2195
2196 /* XXX: NBD Protocol only documents use of FUA with WRITE */
2197 if (request->flags & NBD_CMD_FLAG_FUA) {
2198 ret = blk_co_flush(exp->blk);
2199 if (ret < 0) {
2200 return nbd_send_generic_reply(client, request->handle, ret,
2201 "flush failed", errp);
2202 }
2203 }
2204
2205 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&
2206 request->len && request->type != NBD_CMD_CACHE)
2207 {
2208 return nbd_co_send_sparse_read(client, request->handle, request->from,
2209 data, request->len, errp);
2210 }
2211
2212 ret = blk_pread(exp->blk, request->from + exp->dev_offset, data,
2213 request->len);
2214 if (ret < 0 || request->type == NBD_CMD_CACHE) {
2215 return nbd_send_generic_reply(client, request->handle, ret,
2216 "reading from file failed", errp);
2217 }
2218
2219 if (client->structured_reply) {
2220 if (request->len) {
2221 return nbd_co_send_structured_read(client, request->handle,
2222 request->from, data,
2223 request->len, true, errp);
2224 } else {
2225 return nbd_co_send_structured_done(client, request->handle, errp);
2226 }
2227 } else {
2228 return nbd_co_send_simple_reply(client, request->handle, 0,
2229 data, request->len, errp);
2230 }
2231 }
2232
2233 /* Handle NBD request.
2234 * Return -errno if sending fails. Other errors are reported directly to the
2235 * client as an error reply. */
2236 static coroutine_fn int nbd_handle_request(NBDClient *client,
2237 NBDRequest *request,
2238 uint8_t *data, Error **errp)
2239 {
2240 int ret;
2241 int flags;
2242 NBDExport *exp = client->exp;
2243 char *msg;
2244
2245 switch (request->type) {
2246 case NBD_CMD_READ:
2247 case NBD_CMD_CACHE:
2248 return nbd_do_cmd_read(client, request, data, errp);
2249
2250 case NBD_CMD_WRITE:
2251 flags = 0;
2252 if (request->flags & NBD_CMD_FLAG_FUA) {
2253 flags |= BDRV_REQ_FUA;
2254 }
2255 ret = blk_pwrite(exp->blk, request->from + exp->dev_offset,
2256 data, request->len, flags);
2257 return nbd_send_generic_reply(client, request->handle, ret,
2258 "writing to file failed", errp);
2259
2260 case NBD_CMD_WRITE_ZEROES:
2261 flags = 0;
2262 if (request->flags & NBD_CMD_FLAG_FUA) {
2263 flags |= BDRV_REQ_FUA;
2264 }
2265 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) {
2266 flags |= BDRV_REQ_MAY_UNMAP;
2267 }
2268 ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset,
2269 request->len, flags);
2270 return nbd_send_generic_reply(client, request->handle, ret,
2271 "writing to file failed", errp);
2272
2273 case NBD_CMD_DISC:
2274 /* unreachable, thanks to special case in nbd_co_receive_request() */
2275 abort();
2276
2277 case NBD_CMD_FLUSH:
2278 ret = blk_co_flush(exp->blk);
2279 return nbd_send_generic_reply(client, request->handle, ret,
2280 "flush failed", errp);
2281
2282 case NBD_CMD_TRIM:
2283 ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset,
2284 request->len);
2285 if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) {
2286 ret = blk_co_flush(exp->blk);
2287 }
2288 return nbd_send_generic_reply(client, request->handle, ret,
2289 "discard failed", errp);
2290
2291 case NBD_CMD_BLOCK_STATUS:
2292 if (!request->len) {
2293 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2294 "need non-zero length", errp);
2295 }
2296 if (client->export_meta.valid &&
2297 (client->export_meta.base_allocation ||
2298 client->export_meta.bitmap))
2299 {
2300 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
2301
2302 if (client->export_meta.base_allocation) {
2303 ret = nbd_co_send_block_status(client, request->handle,
2304 blk_bs(exp->blk), request->from,
2305 request->len, dont_fragment,
2306 !client->export_meta.bitmap,
2307 NBD_META_ID_BASE_ALLOCATION,
2308 errp);
2309 if (ret < 0) {
2310 return ret;
2311 }
2312 }
2313
2314 if (client->export_meta.bitmap) {
2315 ret = nbd_co_send_bitmap(client, request->handle,
2316 client->exp->export_bitmap,
2317 request->from, request->len,
2318 dont_fragment,
2319 true, NBD_META_ID_DIRTY_BITMAP, errp);
2320 if (ret < 0) {
2321 return ret;
2322 }
2323 }
2324
2325 return ret;
2326 } else {
2327 return nbd_send_generic_reply(client, request->handle, -EINVAL,
2328 "CMD_BLOCK_STATUS not negotiated",
2329 errp);
2330 }
2331
2332 default:
2333 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
2334 request->type);
2335 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,
2336 errp);
2337 g_free(msg);
2338 return ret;
2339 }
2340 }
2341
2342 /* Owns a reference to the NBDClient passed as opaque. */
2343 static coroutine_fn void nbd_trip(void *opaque)
2344 {
2345 NBDClient *client = opaque;
2346 NBDRequestData *req;
2347 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
2348 int ret;
2349 Error *local_err = NULL;
2350
2351 trace_nbd_trip();
2352 if (client->closing) {
2353 nbd_client_put(client);
2354 return;
2355 }
2356
2357 req = nbd_request_get(client);
2358 ret = nbd_co_receive_request(req, &request, &local_err);
2359 client->recv_coroutine = NULL;
2360
2361 if (client->closing) {
2362 /*
2363 * The client may be closed when we are blocked in
2364 * nbd_co_receive_request()
2365 */
2366 goto done;
2367 }
2368
2369 nbd_client_receive_next_request(client);
2370 if (ret == -EIO) {
2371 goto disconnect;
2372 }
2373
2374 if (ret < 0) {
2375 /* It wans't -EIO, so, according to nbd_co_receive_request()
2376 * semantics, we should return the error to the client. */
2377 Error *export_err = local_err;
2378
2379 local_err = NULL;
2380 ret = nbd_send_generic_reply(client, request.handle, -EINVAL,
2381 error_get_pretty(export_err), &local_err);
2382 error_free(export_err);
2383 } else {
2384 ret = nbd_handle_request(client, &request, req->data, &local_err);
2385 }
2386 if (ret < 0) {
2387 error_prepend(&local_err, "Failed to send reply: ");
2388 goto disconnect;
2389 }
2390
2391 /* We must disconnect after NBD_CMD_WRITE if we did not
2392 * read the payload.
2393 */
2394 if (!req->complete) {
2395 error_setg(&local_err, "Request handling failed in intermediate state");
2396 goto disconnect;
2397 }
2398
2399 done:
2400 nbd_request_put(req);
2401 nbd_client_put(client);
2402 return;
2403
2404 disconnect:
2405 if (local_err) {
2406 error_reportf_err(local_err, "Disconnect client, due to: ");
2407 }
2408 nbd_request_put(req);
2409 client_close(client, true);
2410 nbd_client_put(client);
2411 }
2412
2413 static void nbd_client_receive_next_request(NBDClient *client)
2414 {
2415 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
2416 nbd_client_get(client);
2417 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
2418 aio_co_schedule(client->exp->ctx, client->recv_coroutine);
2419 }
2420 }
2421
2422 static coroutine_fn void nbd_co_client_start(void *opaque)
2423 {
2424 NBDClient *client = opaque;
2425 Error *local_err = NULL;
2426
2427 qemu_co_mutex_init(&client->send_lock);
2428
2429 if (nbd_negotiate(client, &local_err)) {
2430 if (local_err) {
2431 error_report_err(local_err);
2432 }
2433 client_close(client, false);
2434 return;
2435 }
2436
2437 nbd_client_receive_next_request(client);
2438 }
2439
2440 /*
2441 * Create a new client listener using the given channel @sioc.
2442 * Begin servicing it in a coroutine. When the connection closes, call
2443 * @close_fn with an indication of whether the client completed negotiation.
2444 */
2445 void nbd_client_new(QIOChannelSocket *sioc,
2446 QCryptoTLSCreds *tlscreds,
2447 const char *tlsauthz,
2448 void (*close_fn)(NBDClient *, bool))
2449 {
2450 NBDClient *client;
2451 Coroutine *co;
2452
2453 client = g_new0(NBDClient, 1);
2454 client->refcount = 1;
2455 client->tlscreds = tlscreds;
2456 if (tlscreds) {
2457 object_ref(OBJECT(client->tlscreds));
2458 }
2459 client->tlsauthz = g_strdup(tlsauthz);
2460 client->sioc = sioc;
2461 object_ref(OBJECT(client->sioc));
2462 client->ioc = QIO_CHANNEL(sioc);
2463 object_ref(OBJECT(client->ioc));
2464 client->close_fn = close_fn;
2465
2466 co = qemu_coroutine_create(nbd_co_client_start, client);
2467 qemu_coroutine_enter(co);
2468 }
AR7 emulation for QEMU