1 /*
2 * Copyright Red Hat
3 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
4 *
5 * Network Block Device Server Side
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; under version 2 of the License.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include "qemu/osdep.h"
21
22 #include "block/block_int.h"
23 #include "block/export.h"
24 #include "block/dirty-bitmap.h"
25 #include "qapi/error.h"
26 #include "qemu/queue.h"
27 #include "trace.h"
28 #include "nbd-internal.h"
29 #include "qemu/units.h"
30 #include "qemu/memalign.h"
31
32 #define NBD_META_ID_BASE_ALLOCATION 0
33 #define NBD_META_ID_ALLOCATION_DEPTH 1
34 /* Dirty bitmaps use 'NBD_META_ID_DIRTY_BITMAP + i', so keep this id last. */
35 #define NBD_META_ID_DIRTY_BITMAP 2
36
37 /*
38 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical
39 * constant. If an increase is needed, note that the NBD protocol
40 * recommends no larger than 32 mb, so that the client won't consider
41 * the reply as a denial of service attack.
42 */
43 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8)
44
system_errno_to_nbd_errno(int err)45 static int system_errno_to_nbd_errno(int err)
46 {
47 switch (err) {
48 case 0:
49 return NBD_SUCCESS;
50 case EPERM:
51 case EROFS:
52 return NBD_EPERM;
53 case EIO:
54 return NBD_EIO;
55 case ENOMEM:
56 return NBD_ENOMEM;
57 #ifdef EDQUOT
58 case EDQUOT:
59 #endif
60 case EFBIG:
61 case ENOSPC:
62 return NBD_ENOSPC;
63 case EOVERFLOW:
64 return NBD_EOVERFLOW;
65 case ENOTSUP:
66 #if ENOTSUP != EOPNOTSUPP
67 case EOPNOTSUPP:
68 #endif
69 return NBD_ENOTSUP;
70 case ESHUTDOWN:
71 return NBD_ESHUTDOWN;
72 case EINVAL:
73 default:
74 return NBD_EINVAL;
75 }
76 }
77
78 /* Definitions for opaque data types */
79
80 typedef struct NBDRequestData NBDRequestData;
81
82 struct NBDRequestData {
83 NBDClient *client;
84 uint8_t *data;
85 bool complete;
86 };
87
88 struct NBDExport {
89 BlockExport common;
90
91 char *name;
92 char *description;
93 uint64_t size;
94 uint16_t nbdflags;
95 QTAILQ_HEAD(, NBDClient) clients;
96 QTAILQ_ENTRY(NBDExport) next;
97
98 BlockBackend *eject_notifier_blk;
99 Notifier eject_notifier;
100
101 bool allocation_depth;
102 BdrvDirtyBitmap **export_bitmaps;
103 size_t nr_export_bitmaps;
104 };
105
106 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
107
108 /*
109 * NBDMetaContexts represents a list of meta contexts in use,
110 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for
111 * NBD_OPT_LIST_META_CONTEXT.
112 */
113 struct NBDMetaContexts {
114 const NBDExport *exp; /* associated export */
115 size_t count; /* number of negotiated contexts */
116 bool base_allocation; /* export base:allocation context (block status) */
117 bool allocation_depth; /* export qemu:allocation-depth */
118 bool *bitmaps; /*
119 * export qemu:dirty-bitmap:<export bitmap name>,
120 * sized by exp->nr_export_bitmaps
121 */
122 };
123
124 struct NBDClient {
125 int refcount; /* atomic */
126 void (*close_fn)(NBDClient *client, bool negotiated);
127 void *owner;
128
129 QemuMutex lock;
130
131 NBDExport *exp;
132 QCryptoTLSCreds *tlscreds;
133 char *tlsauthz;
134 uint32_t handshake_max_secs;
135 QIOChannelSocket *sioc; /* The underlying data channel */
136 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
137
138 Coroutine *recv_coroutine; /* protected by lock */
139
140 CoMutex send_lock;
141 Coroutine *send_coroutine;
142
143 bool read_yielding; /* protected by lock */
144 bool quiescing; /* protected by lock */
145
146 QTAILQ_ENTRY(NBDClient) next;
147 int nb_requests; /* protected by lock */
148 bool closing; /* protected by lock */
149
150 uint32_t check_align; /* If non-zero, check for aligned client requests */
151
152 NBDMode mode;
153 NBDMetaContexts contexts; /* Negotiated meta contexts */
154
155 uint32_t opt; /* Current option being negotiated */
156 uint32_t optlen; /* remaining length of data in ioc for the option being
157 negotiated now */
158 };
159
160 static void nbd_client_receive_next_request(NBDClient *client);
161
162 /* Basic flow for negotiation
163
164 Server Client
165 Negotiate
166
167 or
168
169 Server Client
170 Negotiate #1
171 Option
172 Negotiate #2
173
174 ----
175
176 followed by
177
178 Server Client
179 Request
180 Response
181 Request
182 Response
183 ...
184 ...
185 Request (type == 2)
186
187 */
188
set_be_option_rep(NBDOptionReply * rep,uint32_t option,uint32_t type,uint32_t length)189 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option,
190 uint32_t type, uint32_t length)
191 {
192 stq_be_p(&rep->magic, NBD_REP_MAGIC);
193 stl_be_p(&rep->option, option);
194 stl_be_p(&rep->type, type);
195 stl_be_p(&rep->length, length);
196 }
197
198 /* Send a reply header, including length, but no payload.
199 * Return -errno on error, 0 on success. */
200 static coroutine_fn int
nbd_negotiate_send_rep_len(NBDClient * client,uint32_t type,uint32_t len,Error ** errp)201 nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type,
202 uint32_t len, Error **errp)
203 {
204 NBDOptionReply rep;
205
206 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt),
207 type, nbd_rep_lookup(type), len);
208
209 assert(len < NBD_MAX_BUFFER_SIZE);
210
211 set_be_option_rep(&rep, client->opt, type, len);
212 return nbd_write(client->ioc, &rep, sizeof(rep), errp);
213 }
214
215 /* Send a reply header with default 0 length.
216 * Return -errno on error, 0 on success. */
217 static coroutine_fn int
nbd_negotiate_send_rep(NBDClient * client,uint32_t type,Error ** errp)218 nbd_negotiate_send_rep(NBDClient *client, uint32_t type, Error **errp)
219 {
220 return nbd_negotiate_send_rep_len(client, type, 0, errp);
221 }
222
223 /* Send an error reply.
224 * Return -errno on error, 0 on success. */
225 static coroutine_fn int G_GNUC_PRINTF(4, 0)
nbd_negotiate_send_rep_verr(NBDClient * client,uint32_t type,Error ** errp,const char * fmt,va_list va)226 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type,
227 Error **errp, const char *fmt, va_list va)
228 {
229 ERRP_GUARD();
230 g_autofree char *msg = NULL;
231 int ret;
232 size_t len;
233
234 msg = g_strdup_vprintf(fmt, va);
235 len = strlen(msg);
236 assert(len < NBD_MAX_STRING_SIZE);
237 trace_nbd_negotiate_send_rep_err(msg);
238 ret = nbd_negotiate_send_rep_len(client, type, len, errp);
239 if (ret < 0) {
240 return ret;
241 }
242 if (nbd_write(client->ioc, msg, len, errp) < 0) {
243 error_prepend(errp, "write failed (error message): ");
244 return -EIO;
245 }
246
247 return 0;
248 }
249
250 /*
251 * Return a malloc'd copy of @name suitable for use in an error reply.
252 */
253 static char *
nbd_sanitize_name(const char * name)254 nbd_sanitize_name(const char *name)
255 {
256 if (strnlen(name, 80) < 80) {
257 return g_strdup(name);
258 }
259 /* XXX Should we also try to sanitize any control characters? */
260 return g_strdup_printf("%.80s...", name);
261 }
262
263 /* Send an error reply.
264 * Return -errno on error, 0 on success. */
265 static coroutine_fn int G_GNUC_PRINTF(4, 5)
nbd_negotiate_send_rep_err(NBDClient * client,uint32_t type,Error ** errp,const char * fmt,...)266 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type,
267 Error **errp, const char *fmt, ...)
268 {
269 va_list va;
270 int ret;
271
272 va_start(va, fmt);
273 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
274 va_end(va);
275 return ret;
276 }
277
278 /* Drop remainder of the current option, and send a reply with the
279 * given error type and message. Return -errno on read or write
280 * failure; or 0 if connection is still live. */
281 static coroutine_fn int G_GNUC_PRINTF(4, 0)
nbd_opt_vdrop(NBDClient * client,uint32_t type,Error ** errp,const char * fmt,va_list va)282 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp,
283 const char *fmt, va_list va)
284 {
285 int ret = nbd_drop(client->ioc, client->optlen, errp);
286
287 client->optlen = 0;
288 if (!ret) {
289 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va);
290 }
291 return ret;
292 }
293
294 static coroutine_fn int G_GNUC_PRINTF(4, 5)
nbd_opt_drop(NBDClient * client,uint32_t type,Error ** errp,const char * fmt,...)295 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp,
296 const char *fmt, ...)
297 {
298 int ret;
299 va_list va;
300
301 va_start(va, fmt);
302 ret = nbd_opt_vdrop(client, type, errp, fmt, va);
303 va_end(va);
304
305 return ret;
306 }
307
308 static coroutine_fn int G_GNUC_PRINTF(3, 4)
nbd_opt_invalid(NBDClient * client,Error ** errp,const char * fmt,...)309 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...)
310 {
311 int ret;
312 va_list va;
313
314 va_start(va, fmt);
315 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va);
316 va_end(va);
317
318 return ret;
319 }
320
321 /* Read size bytes from the unparsed payload of the current option.
322 * If @check_nul, require that no NUL bytes appear in buffer.
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 static coroutine_fn int
nbd_opt_read(NBDClient * client,void * buffer,size_t size,bool check_nul,Error ** errp)326 nbd_opt_read(NBDClient *client, void *buffer, size_t size,
327 bool check_nul, Error **errp)
328 {
329 if (size > client->optlen) {
330 return nbd_opt_invalid(client, errp,
331 "Inconsistent lengths in option %s",
332 nbd_opt_lookup(client->opt));
333 }
334 client->optlen -= size;
335 if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) {
336 return -EIO;
337 }
338
339 if (check_nul && strnlen(buffer, size) != size) {
340 return nbd_opt_invalid(client, errp,
341 "Unexpected embedded NUL in option %s",
342 nbd_opt_lookup(client->opt));
343 }
344 return 1;
345 }
346
347 /* Drop size bytes from the unparsed payload of the current option.
348 * Return -errno on I/O error, 0 if option was completely handled by
349 * sending a reply about inconsistent lengths, or 1 on success. */
350 static coroutine_fn int
nbd_opt_skip(NBDClient * client,size_t size,Error ** errp)351 nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
352 {
353 if (size > client->optlen) {
354 return nbd_opt_invalid(client, errp,
355 "Inconsistent lengths in option %s",
356 nbd_opt_lookup(client->opt));
357 }
358 client->optlen -= size;
359 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
360 }
361
362 /* nbd_opt_read_name
363 *
364 * Read a string with the format:
365 * uint32_t len (<= NBD_MAX_STRING_SIZE)
366 * len bytes string (not 0-terminated)
367 *
368 * On success, @name will be allocated.
369 * If @length is non-null, it will be set to the actual string length.
370 *
371 * Return -errno on I/O error, 0 if option was completely handled by
372 * sending a reply about inconsistent lengths, or 1 on success.
373 */
374 static coroutine_fn int
nbd_opt_read_name(NBDClient * client,char ** name,uint32_t * length,Error ** errp)375 nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length,
376 Error **errp)
377 {
378 int ret;
379 uint32_t len;
380 g_autofree char *local_name = NULL;
381
382 *name = NULL;
383 ret = nbd_opt_read(client, &len, sizeof(len), false, errp);
384 if (ret <= 0) {
385 return ret;
386 }
387 len = cpu_to_be32(len);
388
389 if (len > NBD_MAX_STRING_SIZE) {
390 return nbd_opt_invalid(client, errp,
391 "Invalid name length: %" PRIu32, len);
392 }
393
394 local_name = g_malloc(len + 1);
395 ret = nbd_opt_read(client, local_name, len, true, errp);
396 if (ret <= 0) {
397 return ret;
398 }
399 local_name[len] = '\0';
400
401 if (length) {
402 *length = len;
403 }
404 *name = g_steal_pointer(&local_name);
405
406 return 1;
407 }
408
409 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
410 * Return -errno on error, 0 on success. */
411 static coroutine_fn int
nbd_negotiate_send_rep_list(NBDClient * client,NBDExport * exp,Error ** errp)412 nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, Error **errp)
413 {
414 ERRP_GUARD();
415 size_t name_len, desc_len;
416 uint32_t len;
417 const char *name = exp->name ? exp->name : "";
418 const char *desc = exp->description ? exp->description : "";
419 QIOChannel *ioc = client->ioc;
420 int ret;
421
422 trace_nbd_negotiate_send_rep_list(name, desc);
423 name_len = strlen(name);
424 desc_len = strlen(desc);
425 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE);
426 len = name_len + desc_len + sizeof(len);
427 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp);
428 if (ret < 0) {
429 return ret;
430 }
431
432 len = cpu_to_be32(name_len);
433 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) {
434 error_prepend(errp, "write failed (name length): ");
435 return -EINVAL;
436 }
437
438 if (nbd_write(ioc, name, name_len, errp) < 0) {
439 error_prepend(errp, "write failed (name buffer): ");
440 return -EINVAL;
441 }
442
443 if (nbd_write(ioc, desc, desc_len, errp) < 0) {
444 error_prepend(errp, "write failed (description buffer): ");
445 return -EINVAL;
446 }
447
448 return 0;
449 }
450
451 /* Process the NBD_OPT_LIST command, with a potential series of replies.
452 * Return -errno on error, 0 on success. */
453 static coroutine_fn int
nbd_negotiate_handle_list(NBDClient * client,Error ** errp)454 nbd_negotiate_handle_list(NBDClient *client, Error **errp)
455 {
456 NBDExport *exp;
457 assert(client->opt == NBD_OPT_LIST);
458
459 /* For each export, send a NBD_REP_SERVER reply. */
460 QTAILQ_FOREACH(exp, &exports, next) {
461 if (nbd_negotiate_send_rep_list(client, exp, errp)) {
462 return -EINVAL;
463 }
464 }
465 /* Finish with a NBD_REP_ACK. */
466 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
467 }
468
469 static coroutine_fn void
nbd_check_meta_export(NBDClient * client,NBDExport * exp)470 nbd_check_meta_export(NBDClient *client, NBDExport *exp)
471 {
472 if (exp != client->contexts.exp) {
473 client->contexts.count = 0;
474 }
475 }
476
477 /* Send a reply to NBD_OPT_EXPORT_NAME.
478 * Return -errno on error, 0 on success. */
479 static coroutine_fn int
nbd_negotiate_handle_export_name(NBDClient * client,bool no_zeroes,Error ** errp)480 nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes,
481 Error **errp)
482 {
483 ERRP_GUARD();
484 g_autofree char *name = NULL;
485 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
486 size_t len;
487 int ret;
488 uint16_t myflags;
489
490 /* Client sends:
491 [20 .. xx] export name (length bytes)
492 Server replies:
493 [ 0 .. 7] size
494 [ 8 .. 9] export flags
495 [10 .. 133] reserved (0) [unless no_zeroes]
496 */
497 trace_nbd_negotiate_handle_export_name();
498 if (client->mode >= NBD_MODE_EXTENDED) {
499 error_setg(errp, "Extended headers already negotiated");
500 return -EINVAL;
501 }
502 if (client->optlen > NBD_MAX_STRING_SIZE) {
503 error_setg(errp, "Bad length received");
504 return -EINVAL;
505 }
506 name = g_malloc(client->optlen + 1);
507 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) {
508 return -EIO;
509 }
510 name[client->optlen] = '\0';
511 client->optlen = 0;
512
513 trace_nbd_negotiate_handle_export_name_request(name);
514
515 client->exp = nbd_export_find(name);
516 if (!client->exp) {
517 error_setg(errp, "export not found");
518 return -EINVAL;
519 }
520 nbd_check_meta_export(client, client->exp);
521
522 myflags = client->exp->nbdflags;
523 if (client->mode >= NBD_MODE_STRUCTURED) {
524 myflags |= NBD_FLAG_SEND_DF;
525 }
526 if (client->mode >= NBD_MODE_EXTENDED && client->contexts.count) {
527 myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD;
528 }
529 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags);
530 stq_be_p(buf, client->exp->size);
531 stw_be_p(buf + 8, myflags);
532 len = no_zeroes ? 10 : sizeof(buf);
533 ret = nbd_write(client->ioc, buf, len, errp);
534 if (ret < 0) {
535 error_prepend(errp, "write failed: ");
536 return ret;
537 }
538
539 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
540 blk_exp_ref(&client->exp->common);
541
542 return 0;
543 }
544
545 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes.
546 * The buffer does NOT include the info type prefix.
547 * Return -errno on error, 0 if ready to send more. */
548 static coroutine_fn int
nbd_negotiate_send_info(NBDClient * client,uint16_t info,uint32_t length,void * buf,Error ** errp)549 nbd_negotiate_send_info(NBDClient *client, uint16_t info, uint32_t length,
550 void *buf, Error **errp)
551 {
552 int rc;
553
554 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length);
555 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO,
556 sizeof(info) + length, errp);
557 if (rc < 0) {
558 return rc;
559 }
560 info = cpu_to_be16(info);
561 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) {
562 return -EIO;
563 }
564 if (nbd_write(client->ioc, buf, length, errp) < 0) {
565 return -EIO;
566 }
567 return 0;
568 }
569
570 /* nbd_reject_length: Handle any unexpected payload.
571 * @fatal requests that we quit talking to the client, even if we are able
572 * to successfully send an error reply.
573 * Return:
574 * -errno transmission error occurred or @fatal was requested, errp is set
575 * 0 error message successfully sent to client, errp is not set
576 */
577 static coroutine_fn int
nbd_reject_length(NBDClient * client,bool fatal,Error ** errp)578 nbd_reject_length(NBDClient *client, bool fatal, Error **errp)
579 {
580 int ret;
581
582 assert(client->optlen);
583 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length",
584 nbd_opt_lookup(client->opt));
585 if (fatal && !ret) {
586 error_setg(errp, "option '%s' has unexpected length",
587 nbd_opt_lookup(client->opt));
588 return -EINVAL;
589 }
590 return ret;
591 }
592
593 /* Handle NBD_OPT_INFO and NBD_OPT_GO.
594 * Return -errno on error, 0 if ready for next option, and 1 to move
595 * into transmission phase. */
596 static coroutine_fn int
nbd_negotiate_handle_info(NBDClient * client,Error ** errp)597 nbd_negotiate_handle_info(NBDClient *client, Error **errp)
598 {
599 int rc;
600 g_autofree char *name = NULL;
601 NBDExport *exp;
602 uint16_t requests;
603 uint16_t request;
604 uint32_t namelen = 0;
605 bool sendname = false;
606 bool blocksize = false;
607 uint32_t sizes[3];
608 char buf[sizeof(uint64_t) + sizeof(uint16_t)];
609 uint32_t check_align = 0;
610 uint16_t myflags;
611
612 /* Client sends:
613 4 bytes: L, name length (can be 0)
614 L bytes: export name
615 2 bytes: N, number of requests (can be 0)
616 N * 2 bytes: N requests
617 */
618 rc = nbd_opt_read_name(client, &name, &namelen, errp);
619 if (rc <= 0) {
620 return rc;
621 }
622 trace_nbd_negotiate_handle_export_name_request(name);
623
624 rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp);
625 if (rc <= 0) {
626 return rc;
627 }
628 requests = be16_to_cpu(requests);
629 trace_nbd_negotiate_handle_info_requests(requests);
630 while (requests--) {
631 rc = nbd_opt_read(client, &request, sizeof(request), false, errp);
632 if (rc <= 0) {
633 return rc;
634 }
635 request = be16_to_cpu(request);
636 trace_nbd_negotiate_handle_info_request(request,
637 nbd_info_lookup(request));
638 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE;
639 * everything else is either a request we don't know or
640 * something we send regardless of request */
641 switch (request) {
642 case NBD_INFO_NAME:
643 sendname = true;
644 break;
645 case NBD_INFO_BLOCK_SIZE:
646 blocksize = true;
647 break;
648 }
649 }
650 if (client->optlen) {
651 return nbd_reject_length(client, false, errp);
652 }
653
654 exp = nbd_export_find(name);
655 if (!exp) {
656 g_autofree char *sane_name = nbd_sanitize_name(name);
657
658 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN,
659 errp, "export '%s' not present",
660 sane_name);
661 }
662 if (client->opt == NBD_OPT_GO) {
663 nbd_check_meta_export(client, exp);
664 }
665
666 /* Don't bother sending NBD_INFO_NAME unless client requested it */
667 if (sendname) {
668 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name,
669 errp);
670 if (rc < 0) {
671 return rc;
672 }
673 }
674
675 /* Send NBD_INFO_DESCRIPTION only if available, regardless of
676 * client request */
677 if (exp->description) {
678 size_t len = strlen(exp->description);
679
680 assert(len <= NBD_MAX_STRING_SIZE);
681 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION,
682 len, exp->description, errp);
683 if (rc < 0) {
684 return rc;
685 }
686 }
687
688 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size
689 * according to whether the client requested it, and according to
690 * whether this is OPT_INFO or OPT_GO. */
691 /* minimum - 1 for back-compat, or actual if client will obey it. */
692 if (client->opt == NBD_OPT_INFO || blocksize) {
693 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk);
694 } else {
695 sizes[0] = 1;
696 }
697 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE);
698 /* preferred - Hard-code to 4096 for now.
699 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */
700 sizes[1] = MAX(4096, sizes[0]);
701 /* maximum - At most 32M, but smaller as appropriate. */
702 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE);
703 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]);
704 sizes[0] = cpu_to_be32(sizes[0]);
705 sizes[1] = cpu_to_be32(sizes[1]);
706 sizes[2] = cpu_to_be32(sizes[2]);
707 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE,
708 sizeof(sizes), sizes, errp);
709 if (rc < 0) {
710 return rc;
711 }
712
713 /* Send NBD_INFO_EXPORT always */
714 myflags = exp->nbdflags;
715 if (client->mode >= NBD_MODE_STRUCTURED) {
716 myflags |= NBD_FLAG_SEND_DF;
717 }
718 if (client->mode >= NBD_MODE_EXTENDED &&
719 (client->contexts.count || client->opt == NBD_OPT_INFO)) {
720 myflags |= NBD_FLAG_BLOCK_STAT_PAYLOAD;
721 }
722 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags);
723 stq_be_p(buf, exp->size);
724 stw_be_p(buf + 8, myflags);
725 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT,
726 sizeof(buf), buf, errp);
727 if (rc < 0) {
728 return rc;
729 }
730
731 /*
732 * If the client is just asking for NBD_OPT_INFO, but forgot to
733 * request block sizes in a situation that would impact
734 * performance, then return an error. But for NBD_OPT_GO, we
735 * tolerate all clients, regardless of alignments.
736 */
737 if (client->opt == NBD_OPT_INFO && !blocksize &&
738 blk_get_request_alignment(exp->common.blk) > 1) {
739 return nbd_negotiate_send_rep_err(client,
740 NBD_REP_ERR_BLOCK_SIZE_REQD,
741 errp,
742 "request NBD_INFO_BLOCK_SIZE to "
743 "use this export");
744 }
745
746 /* Final reply */
747 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
748 if (rc < 0) {
749 return rc;
750 }
751
752 if (client->opt == NBD_OPT_GO) {
753 client->exp = exp;
754 client->check_align = check_align;
755 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
756 blk_exp_ref(&client->exp->common);
757 rc = 1;
758 }
759 return rc;
760 }
761
762 /* Callback to learn when QIO TLS upgrade is complete */
763 struct NBDTLSServerHandshakeData {
764 bool complete;
765 Error *error;
766 Coroutine *co;
767 };
768
769 static void
nbd_server_tls_handshake(QIOTask * task,void * opaque)770 nbd_server_tls_handshake(QIOTask *task, void *opaque)
771 {
772 struct NBDTLSServerHandshakeData *data = opaque;
773
774 qio_task_propagate_error(task, &data->error);
775 data->complete = true;
776 if (!qemu_coroutine_entered(data->co)) {
777 aio_co_wake(data->co);
778 }
779 }
780
781 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
782 * new channel for all further (now-encrypted) communication. */
783 static coroutine_fn QIOChannel *
nbd_negotiate_handle_starttls(NBDClient * client,Error ** errp)784 nbd_negotiate_handle_starttls(NBDClient *client, Error **errp)
785 {
786 QIOChannel *ioc;
787 QIOChannelTLS *tioc;
788 struct NBDTLSServerHandshakeData data = { 0 };
789
790 assert(client->opt == NBD_OPT_STARTTLS);
791
792 trace_nbd_negotiate_handle_starttls();
793 ioc = client->ioc;
794
795 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) {
796 return NULL;
797 }
798
799 tioc = qio_channel_tls_new_server(ioc,
800 client->tlscreds,
801 client->tlsauthz,
802 errp);
803 if (!tioc) {
804 return NULL;
805 }
806
807 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
808 trace_nbd_negotiate_handle_starttls_handshake();
809 data.co = qemu_coroutine_self();
810 qio_channel_tls_handshake(tioc,
811 nbd_server_tls_handshake,
812 &data,
813 NULL,
814 NULL);
815
816 if (!data.complete) {
817 qemu_coroutine_yield();
818 assert(data.complete);
819 }
820
821 if (data.error) {
822 object_unref(OBJECT(tioc));
823 error_propagate(errp, data.error);
824 return NULL;
825 }
826
827 return QIO_CHANNEL(tioc);
828 }
829
830 /* nbd_negotiate_send_meta_context
831 *
832 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
833 *
834 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
835 */
836 static coroutine_fn int
nbd_negotiate_send_meta_context(NBDClient * client,const char * context,uint32_t context_id,Error ** errp)837 nbd_negotiate_send_meta_context(NBDClient *client, const char *context,
838 uint32_t context_id, Error **errp)
839 {
840 NBDOptionReplyMetaContext opt;
841 struct iovec iov[] = {
842 {.iov_base = &opt, .iov_len = sizeof(opt)},
843 {.iov_base = (void *)context, .iov_len = strlen(context)}
844 };
845
846 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE);
847 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
848 context_id = 0;
849 }
850
851 trace_nbd_negotiate_meta_query_reply(context, context_id);
852 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
853 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
854 stl_be_p(&opt.context_id, context_id);
855
856 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
857 }
858
859 /*
860 * Return true if @query matches @pattern, or if @query is empty when
861 * the @client is performing _LIST_.
862 */
863 static coroutine_fn bool
nbd_meta_empty_or_pattern(NBDClient * client,const char * pattern,const char * query)864 nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern,
865 const char *query)
866 {
867 if (!*query) {
868 trace_nbd_negotiate_meta_query_parse("empty");
869 return client->opt == NBD_OPT_LIST_META_CONTEXT;
870 }
871 if (strcmp(query, pattern) == 0) {
872 trace_nbd_negotiate_meta_query_parse(pattern);
873 return true;
874 }
875 trace_nbd_negotiate_meta_query_skip("pattern not matched");
876 return false;
877 }
878
879 /*
880 * Return true and adjust @str in place if it begins with @prefix.
881 */
882 static coroutine_fn bool
nbd_strshift(const char ** str,const char * prefix)883 nbd_strshift(const char **str, const char *prefix)
884 {
885 size_t len = strlen(prefix);
886
887 if (strncmp(*str, prefix, len) == 0) {
888 *str += len;
889 return true;
890 }
891 return false;
892 }
893
894 /* nbd_meta_base_query
895 *
896 * Handle queries to 'base' namespace. For now, only the base:allocation
897 * context is available. Return true if @query has been handled.
898 */
899 static coroutine_fn bool
nbd_meta_base_query(NBDClient * client,NBDMetaContexts * meta,const char * query)900 nbd_meta_base_query(NBDClient *client, NBDMetaContexts *meta,
901 const char *query)
902 {
903 if (!nbd_strshift(&query, "base:")) {
904 return false;
905 }
906 trace_nbd_negotiate_meta_query_parse("base:");
907
908 if (nbd_meta_empty_or_pattern(client, "allocation", query)) {
909 meta->base_allocation = true;
910 }
911 return true;
912 }
913
914 /* nbd_meta_qemu_query
915 *
916 * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap:
917 * and qemu:allocation-depth contexts are available. Return true if @query
918 * has been handled.
919 */
920 static coroutine_fn bool
nbd_meta_qemu_query(NBDClient * client,NBDMetaContexts * meta,const char * query)921 nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *meta,
922 const char *query)
923 {
924 size_t i;
925
926 if (!nbd_strshift(&query, "qemu:")) {
927 return false;
928 }
929 trace_nbd_negotiate_meta_query_parse("qemu:");
930
931 if (!*query) {
932 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
933 meta->allocation_depth = meta->exp->allocation_depth;
934 if (meta->exp->nr_export_bitmaps) {
935 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
936 }
937 }
938 trace_nbd_negotiate_meta_query_parse("empty");
939 return true;
940 }
941
942 if (strcmp(query, "allocation-depth") == 0) {
943 trace_nbd_negotiate_meta_query_parse("allocation-depth");
944 meta->allocation_depth = meta->exp->allocation_depth;
945 return true;
946 }
947
948 if (nbd_strshift(&query, "dirty-bitmap:")) {
949 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:");
950 if (!*query) {
951 if (client->opt == NBD_OPT_LIST_META_CONTEXT &&
952 meta->exp->nr_export_bitmaps) {
953 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
954 }
955 trace_nbd_negotiate_meta_query_parse("empty");
956 return true;
957 }
958
959 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) {
960 const char *bm_name;
961
962 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]);
963 if (strcmp(bm_name, query) == 0) {
964 meta->bitmaps[i] = true;
965 trace_nbd_negotiate_meta_query_parse(query);
966 return true;
967 }
968 }
969 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap match");
970 return true;
971 }
972
973 trace_nbd_negotiate_meta_query_skip("unknown qemu context");
974 return true;
975 }
976
977 /* nbd_negotiate_meta_query
978 *
979 * Parse namespace name and call corresponding function to parse body of the
980 * query.
981 *
982 * The only supported namespaces are 'base' and 'qemu'.
983 *
984 * Return -errno on I/O error, 0 if option was completely handled by
985 * sending a reply about inconsistent lengths, or 1 on success. */
986 static coroutine_fn int
nbd_negotiate_meta_query(NBDClient * client,NBDMetaContexts * meta,Error ** errp)987 nbd_negotiate_meta_query(NBDClient *client,
988 NBDMetaContexts *meta, Error **errp)
989 {
990 int ret;
991 g_autofree char *query = NULL;
992 uint32_t len;
993
994 ret = nbd_opt_read(client, &len, sizeof(len), false, errp);
995 if (ret <= 0) {
996 return ret;
997 }
998 len = cpu_to_be32(len);
999
1000 if (len > NBD_MAX_STRING_SIZE) {
1001 trace_nbd_negotiate_meta_query_skip("length too long");
1002 return nbd_opt_skip(client, len, errp);
1003 }
1004
1005 query = g_malloc(len + 1);
1006 ret = nbd_opt_read(client, query, len, true, errp);
1007 if (ret <= 0) {
1008 return ret;
1009 }
1010 query[len] = '\0';
1011
1012 if (nbd_meta_base_query(client, meta, query)) {
1013 return 1;
1014 }
1015 if (nbd_meta_qemu_query(client, meta, query)) {
1016 return 1;
1017 }
1018
1019 trace_nbd_negotiate_meta_query_skip("unknown namespace");
1020 return 1;
1021 }
1022
1023 /* nbd_negotiate_meta_queries
1024 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
1025 *
1026 * Return -errno on I/O error, or 0 if option was completely handled. */
1027 static coroutine_fn int
nbd_negotiate_meta_queries(NBDClient * client,Error ** errp)1028 nbd_negotiate_meta_queries(NBDClient *client, Error **errp)
1029 {
1030 int ret;
1031 g_autofree char *export_name = NULL;
1032 /* Mark unused to work around https://bugs.llvm.org/show_bug.cgi?id=3888 */
1033 g_autofree G_GNUC_UNUSED bool *bitmaps = NULL;
1034 NBDMetaContexts local_meta = {0};
1035 NBDMetaContexts *meta;
1036 uint32_t nb_queries;
1037 size_t i;
1038 size_t count = 0;
1039
1040 if (client->opt == NBD_OPT_SET_META_CONTEXT &&
1041 client->mode < NBD_MODE_STRUCTURED) {
1042 return nbd_opt_invalid(client, errp,
1043 "request option '%s' when structured reply "
1044 "is not negotiated",
1045 nbd_opt_lookup(client->opt));
1046 }
1047
1048 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
1049 /* Only change the caller's meta on SET. */
1050 meta = &local_meta;
1051 } else {
1052 meta = &client->contexts;
1053 }
1054
1055 g_free(meta->bitmaps);
1056 memset(meta, 0, sizeof(*meta));
1057
1058 ret = nbd_opt_read_name(client, &export_name, NULL, errp);
1059 if (ret <= 0) {
1060 return ret;
1061 }
1062
1063 meta->exp = nbd_export_find(export_name);
1064 if (meta->exp == NULL) {
1065 g_autofree char *sane_name = nbd_sanitize_name(export_name);
1066
1067 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
1068 "export '%s' not present", sane_name);
1069 }
1070 meta->bitmaps = g_new0(bool, meta->exp->nr_export_bitmaps);
1071 if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
1072 bitmaps = meta->bitmaps;
1073 }
1074
1075 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp);
1076 if (ret <= 0) {
1077 return ret;
1078 }
1079 nb_queries = cpu_to_be32(nb_queries);
1080 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt),
1081 export_name, nb_queries);
1082
1083 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
1084 /* enable all known contexts */
1085 meta->base_allocation = true;
1086 meta->allocation_depth = meta->exp->allocation_depth;
1087 if (meta->exp->nr_export_bitmaps) {
1088 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps);
1089 }
1090 } else {
1091 for (i = 0; i < nb_queries; ++i) {
1092 ret = nbd_negotiate_meta_query(client, meta, errp);
1093 if (ret <= 0) {
1094 return ret;
1095 }
1096 }
1097 }
1098
1099 if (meta->base_allocation) {
1100 ret = nbd_negotiate_send_meta_context(client, "base:allocation",
1101 NBD_META_ID_BASE_ALLOCATION,
1102 errp);
1103 if (ret < 0) {
1104 return ret;
1105 }
1106 count++;
1107 }
1108
1109 if (meta->allocation_depth) {
1110 ret = nbd_negotiate_send_meta_context(client, "qemu:allocation-depth",
1111 NBD_META_ID_ALLOCATION_DEPTH,
1112 errp);
1113 if (ret < 0) {
1114 return ret;
1115 }
1116 count++;
1117 }
1118
1119 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) {
1120 const char *bm_name;
1121 g_autofree char *context = NULL;
1122
1123 if (!meta->bitmaps[i]) {
1124 continue;
1125 }
1126
1127 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]);
1128 context = g_strdup_printf("qemu:dirty-bitmap:%s", bm_name);
1129
1130 ret = nbd_negotiate_send_meta_context(client, context,
1131 NBD_META_ID_DIRTY_BITMAP + i,
1132 errp);
1133 if (ret < 0) {
1134 return ret;
1135 }
1136 count++;
1137 }
1138
1139 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1140 if (ret == 0) {
1141 meta->count = count;
1142 }
1143
1144 return ret;
1145 }
1146
1147 /* nbd_negotiate_options
1148 * Process all NBD_OPT_* client option commands, during fixed newstyle
1149 * negotiation.
1150 * Return:
1151 * -errno on error, errp is set
1152 * 0 on successful negotiation, errp is not set
1153 * 1 if client sent NBD_OPT_ABORT (i.e. on valid disconnect) or never
1154 * wrote anything (i.e. port probe); errp is not set
1155 */
1156 static coroutine_fn int
nbd_negotiate_options(NBDClient * client,Error ** errp)1157 nbd_negotiate_options(NBDClient *client, Error **errp)
1158 {
1159 uint32_t flags;
1160 bool fixedNewstyle = false;
1161 bool no_zeroes = false;
1162
1163 /* Client sends:
1164 [ 0 .. 3] client flags
1165
1166 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO:
1167 [ 0 .. 7] NBD_OPTS_MAGIC
1168 [ 8 .. 11] NBD option
1169 [12 .. 15] Data length
1170 ... Rest of request
1171
1172 [ 0 .. 7] NBD_OPTS_MAGIC
1173 [ 8 .. 11] Second NBD option
1174 [12 .. 15] Data length
1175 ... Rest of request
1176 */
1177
1178 /*
1179 * Intentionally ignore errors on this first read - we do not want
1180 * to be noisy about a mere port probe, but only for clients that
1181 * start talking the protocol and then quit abruptly.
1182 */
1183 if (nbd_read32(client->ioc, &flags, "flags", NULL) < 0) {
1184 return 1;
1185 }
1186 client->mode = NBD_MODE_EXPORT_NAME;
1187 trace_nbd_negotiate_options_flags(flags);
1188 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
1189 fixedNewstyle = true;
1190 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
1191 client->mode = NBD_MODE_SIMPLE;
1192 }
1193 if (flags & NBD_FLAG_C_NO_ZEROES) {
1194 no_zeroes = true;
1195 flags &= ~NBD_FLAG_C_NO_ZEROES;
1196 }
1197 if (flags != 0) {
1198 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
1199 return -EINVAL;
1200 }
1201
1202 while (1) {
1203 int ret;
1204 uint32_t option, length;
1205 uint64_t magic;
1206
1207 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) {
1208 return -EINVAL;
1209 }
1210 trace_nbd_negotiate_options_check_magic(magic);
1211 if (magic != NBD_OPTS_MAGIC) {
1212 error_setg(errp, "Bad magic received");
1213 return -EINVAL;
1214 }
1215
1216 if (nbd_read32(client->ioc, &option, "option", errp) < 0) {
1217 return -EINVAL;
1218 }
1219 client->opt = option;
1220
1221 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) {
1222 return -EINVAL;
1223 }
1224 assert(!client->optlen);
1225 client->optlen = length;
1226
1227 if (length > NBD_MAX_BUFFER_SIZE) {
1228 error_setg(errp, "len (%" PRIu32 ") is larger than max len (%u)",
1229 length, NBD_MAX_BUFFER_SIZE);
1230 return -EINVAL;
1231 }
1232
1233 trace_nbd_negotiate_options_check_option(option,
1234 nbd_opt_lookup(option));
1235 if (client->tlscreds &&
1236 client->ioc == (QIOChannel *)client->sioc) {
1237 QIOChannel *tioc;
1238 if (!fixedNewstyle) {
1239 error_setg(errp, "Unsupported option 0x%" PRIx32, option);
1240 return -EINVAL;
1241 }
1242 switch (option) {
1243 case NBD_OPT_STARTTLS:
1244 if (length) {
1245 /* Unconditionally drop the connection if the client
1246 * can't start a TLS negotiation correctly */
1247 return nbd_reject_length(client, true, errp);
1248 }
1249 tioc = nbd_negotiate_handle_starttls(client, errp);
1250 if (!tioc) {
1251 return -EIO;
1252 }
1253 ret = 0;
1254 object_unref(OBJECT(client->ioc));
1255 client->ioc = tioc;
1256 break;
1257
1258 case NBD_OPT_EXPORT_NAME:
1259 /* No way to return an error to client, so drop connection */
1260 error_setg(errp, "Option 0x%x not permitted before TLS",
1261 option);
1262 return -EINVAL;
1263
1264 default:
1265 /* Let the client keep trying, unless they asked to
1266 * quit. Always try to give an error back to the
1267 * client; but when replying to OPT_ABORT, be aware
1268 * that the client may hang up before receiving the
1269 * error, in which case we are fine ignoring the
1270 * resulting EPIPE. */
1271 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD,
1272 option == NBD_OPT_ABORT ? NULL : errp,
1273 "Option 0x%" PRIx32
1274 " not permitted before TLS", option);
1275 if (option == NBD_OPT_ABORT) {
1276 return 1;
1277 }
1278 break;
1279 }
1280 } else if (fixedNewstyle) {
1281 switch (option) {
1282 case NBD_OPT_LIST:
1283 if (length) {
1284 ret = nbd_reject_length(client, false, errp);
1285 } else {
1286 ret = nbd_negotiate_handle_list(client, errp);
1287 }
1288 break;
1289
1290 case NBD_OPT_ABORT:
1291 /* NBD spec says we must try to reply before
1292 * disconnecting, but that we must also tolerate
1293 * guests that don't wait for our reply. */
1294 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL);
1295 return 1;
1296
1297 case NBD_OPT_EXPORT_NAME:
1298 return nbd_negotiate_handle_export_name(client, no_zeroes,
1299 errp);
1300
1301 case NBD_OPT_INFO:
1302 case NBD_OPT_GO:
1303 ret = nbd_negotiate_handle_info(client, errp);
1304 if (ret == 1) {
1305 assert(option == NBD_OPT_GO);
1306 return 0;
1307 }
1308 break;
1309
1310 case NBD_OPT_STARTTLS:
1311 if (length) {
1312 ret = nbd_reject_length(client, false, errp);
1313 } else if (client->tlscreds) {
1314 ret = nbd_negotiate_send_rep_err(client,
1315 NBD_REP_ERR_INVALID, errp,
1316 "TLS already enabled");
1317 } else {
1318 ret = nbd_negotiate_send_rep_err(client,
1319 NBD_REP_ERR_POLICY, errp,
1320 "TLS not configured");
1321 }
1322 break;
1323
1324 case NBD_OPT_STRUCTURED_REPLY:
1325 if (length) {
1326 ret = nbd_reject_length(client, false, errp);
1327 } else if (client->mode >= NBD_MODE_EXTENDED) {
1328 ret = nbd_negotiate_send_rep_err(
1329 client, NBD_REP_ERR_EXT_HEADER_REQD, errp,
1330 "extended headers already negotiated");
1331 } else if (client->mode >= NBD_MODE_STRUCTURED) {
1332 ret = nbd_negotiate_send_rep_err(
1333 client, NBD_REP_ERR_INVALID, errp,
1334 "structured reply already negotiated");
1335 } else {
1336 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1337 client->mode = NBD_MODE_STRUCTURED;
1338 }
1339 break;
1340
1341 case NBD_OPT_LIST_META_CONTEXT:
1342 case NBD_OPT_SET_META_CONTEXT:
1343 ret = nbd_negotiate_meta_queries(client, errp);
1344 break;
1345
1346 case NBD_OPT_EXTENDED_HEADERS:
1347 if (length) {
1348 ret = nbd_reject_length(client, false, errp);
1349 } else if (client->mode >= NBD_MODE_EXTENDED) {
1350 ret = nbd_negotiate_send_rep_err(
1351 client, NBD_REP_ERR_INVALID, errp,
1352 "extended headers already negotiated");
1353 } else {
1354 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
1355 client->mode = NBD_MODE_EXTENDED;
1356 }
1357 break;
1358
1359 default:
1360 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,
1361 "Unsupported option %" PRIu32 " (%s)",
1362 option, nbd_opt_lookup(option));
1363 break;
1364 }
1365 } else {
1366 /*
1367 * If broken new-style we should drop the connection
1368 * for anything except NBD_OPT_EXPORT_NAME
1369 */
1370 switch (option) {
1371 case NBD_OPT_EXPORT_NAME:
1372 return nbd_negotiate_handle_export_name(client, no_zeroes,
1373 errp);
1374
1375 default:
1376 error_setg(errp, "Unsupported option %" PRIu32 " (%s)",
1377 option, nbd_opt_lookup(option));
1378 return -EINVAL;
1379 }
1380 }
1381 if (ret < 0) {
1382 return ret;
1383 }
1384 }
1385 }
1386
1387 /* nbd_negotiate
1388 * Return:
1389 * -errno on error, errp is set
1390 * 0 on successful negotiation, errp is not set
1391 * 1 if client sent NBD_OPT_ABORT (i.e. on valid disconnect) or never
1392 * wrote anything (i.e. port probe); errp is not set
1393 */
nbd_negotiate(NBDClient * client,Error ** errp)1394 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
1395 {
1396 ERRP_GUARD();
1397 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
1398 int ret;
1399
1400 /* Old style negotiation header, no room for options
1401 [ 0 .. 7] passwd ("NBDMAGIC")
1402 [ 8 .. 15] magic (NBD_CLIENT_MAGIC)
1403 [16 .. 23] size
1404 [24 .. 27] export flags (zero-extended)
1405 [28 .. 151] reserved (0)
1406
1407 New style negotiation header, client can send options
1408 [ 0 .. 7] passwd ("NBDMAGIC")
1409 [ 8 .. 15] magic (NBD_OPTS_MAGIC)
1410 [16 .. 17] server flags (0)
1411 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO....
1412 */
1413
1414 qio_channel_set_blocking(client->ioc, false, NULL);
1415 qio_channel_set_follow_coroutine_ctx(client->ioc, true);
1416
1417 trace_nbd_negotiate_begin();
1418 memcpy(buf, "NBDMAGIC", 8);
1419
1420 stq_be_p(buf + 8, NBD_OPTS_MAGIC);
1421 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
1422
1423 /*
1424 * Be silent about failure to write our greeting: there is nothing
1425 * wrong with a client testing if our port is alive.
1426 */
1427 if (nbd_write(client->ioc, buf, 18, NULL) < 0) {
1428 return 1;
1429 }
1430 ret = nbd_negotiate_options(client, errp);
1431 if (ret != 0) {
1432 if (ret < 0) {
1433 error_prepend(errp, "option negotiation failed: ");
1434 }
1435 return ret;
1436 }
1437
1438 assert(!client->optlen);
1439 trace_nbd_negotiate_success();
1440
1441 return 0;
1442 }
1443
1444 /* nbd_read_eof
1445 * Tries to read @size bytes from @ioc. This is a local implementation of
1446 * qio_channel_readv_all_eof. We have it here because we need it to be
1447 * interruptible and to know when the coroutine is yielding.
1448 * Returns 1 on success
1449 * 0 on eof, when no data was read (errp is not set)
1450 * negative errno on failure (errp is set)
1451 */
1452 static inline int coroutine_fn
nbd_read_eof(NBDClient * client,void * buffer,size_t size,Error ** errp)1453 nbd_read_eof(NBDClient *client, void *buffer, size_t size, Error **errp)
1454 {
1455 bool partial = false;
1456
1457 assert(size);
1458 while (size > 0) {
1459 struct iovec iov = { .iov_base = buffer, .iov_len = size };
1460 ssize_t len;
1461
1462 len = qio_channel_readv(client->ioc, &iov, 1, errp);
1463 if (len == QIO_CHANNEL_ERR_BLOCK) {
1464 WITH_QEMU_LOCK_GUARD(&client->lock) {
1465 client->read_yielding = true;
1466
1467 /* Prompt main loop thread to re-run nbd_drained_poll() */
1468 aio_wait_kick();
1469 }
1470 qio_channel_yield(client->ioc, G_IO_IN);
1471 WITH_QEMU_LOCK_GUARD(&client->lock) {
1472 client->read_yielding = false;
1473 if (client->quiescing) {
1474 return -EAGAIN;
1475 }
1476 }
1477 continue;
1478 } else if (len < 0) {
1479 return -EIO;
1480 } else if (len == 0) {
1481 if (partial) {
1482 error_setg(errp,
1483 "Unexpected end-of-file before all bytes were read");
1484 return -EIO;
1485 } else {
1486 return 0;
1487 }
1488 }
1489
1490 partial = true;
1491 size -= len;
1492 buffer = (uint8_t *) buffer + len;
1493 }
1494 return 1;
1495 }
1496
nbd_receive_request(NBDClient * client,NBDRequest * request,Error ** errp)1497 static int coroutine_fn nbd_receive_request(NBDClient *client, NBDRequest *request,
1498 Error **errp)
1499 {
1500 uint8_t buf[NBD_EXTENDED_REQUEST_SIZE];
1501 uint32_t magic, expect;
1502 int ret;
1503 size_t size = client->mode >= NBD_MODE_EXTENDED ?
1504 NBD_EXTENDED_REQUEST_SIZE : NBD_REQUEST_SIZE;
1505
1506 ret = nbd_read_eof(client, buf, size, errp);
1507 if (ret < 0) {
1508 return ret;
1509 }
1510 if (ret == 0) {
1511 return -EIO;
1512 }
1513
1514 /*
1515 * Compact request
1516 * [ 0 .. 3] magic (NBD_REQUEST_MAGIC)
1517 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
1518 * [ 6 .. 7] type (NBD_CMD_READ, ...)
1519 * [ 8 .. 15] cookie
1520 * [16 .. 23] from
1521 * [24 .. 27] len
1522 * Extended request
1523 * [ 0 .. 3] magic (NBD_EXTENDED_REQUEST_MAGIC)
1524 * [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, NBD_CMD_FLAG_PAYLOAD_LEN, ...)
1525 * [ 6 .. 7] type (NBD_CMD_READ, ...)
1526 * [ 8 .. 15] cookie
1527 * [16 .. 23] from
1528 * [24 .. 31] len
1529 */
1530
1531 magic = ldl_be_p(buf);
1532 request->flags = lduw_be_p(buf + 4);
1533 request->type = lduw_be_p(buf + 6);
1534 request->cookie = ldq_be_p(buf + 8);
1535 request->from = ldq_be_p(buf + 16);
1536 if (client->mode >= NBD_MODE_EXTENDED) {
1537 request->len = ldq_be_p(buf + 24);
1538 expect = NBD_EXTENDED_REQUEST_MAGIC;
1539 } else {
1540 request->len = (uint32_t)ldl_be_p(buf + 24); /* widen 32 to 64 bits */
1541 expect = NBD_REQUEST_MAGIC;
1542 }
1543
1544 trace_nbd_receive_request(magic, request->flags, request->type,
1545 request->from, request->len);
1546
1547 if (magic != expect) {
1548 error_setg(errp, "invalid magic (got 0x%" PRIx32 ", expected 0x%"
1549 PRIx32 ")", magic, expect);
1550 return -EINVAL;
1551 }
1552 return 0;
1553 }
1554
1555 #define MAX_NBD_REQUESTS 16
1556
1557 /* Runs in export AioContext and main loop thread */
nbd_client_get(NBDClient * client)1558 void nbd_client_get(NBDClient *client)
1559 {
1560 qatomic_inc(&client->refcount);
1561 }
1562
nbd_client_put(NBDClient * client)1563 void nbd_client_put(NBDClient *client)
1564 {
1565 assert(qemu_in_main_thread());
1566
1567 if (qatomic_fetch_dec(&client->refcount) == 1) {
1568 /* The last reference should be dropped by client->close,
1569 * which is called by client_close.
1570 */
1571 assert(client->closing);
1572
1573 object_unref(OBJECT(client->sioc));
1574 object_unref(OBJECT(client->ioc));
1575 if (client->tlscreds) {
1576 object_unref(OBJECT(client->tlscreds));
1577 }
1578 g_free(client->tlsauthz);
1579 if (client->exp) {
1580 QTAILQ_REMOVE(&client->exp->clients, client, next);
1581 blk_exp_unref(&client->exp->common);
1582 }
1583 g_free(client->contexts.bitmaps);
1584 qemu_mutex_destroy(&client->lock);
1585 g_free(client);
1586 }
1587 }
1588
1589 /*
1590 * Tries to release the reference to @client, but only if other references
1591 * remain. This is an optimization for the common case where we want to avoid
1592 * the expense of scheduling nbd_client_put() in the main loop thread.
1593 *
1594 * Returns true upon success or false if the reference was not released because
1595 * it is the last reference.
1596 */
nbd_client_put_nonzero(NBDClient * client)1597 static bool nbd_client_put_nonzero(NBDClient *client)
1598 {
1599 int old = qatomic_read(&client->refcount);
1600 int expected;
1601
1602 do {
1603 if (old == 1) {
1604 return false;
1605 }
1606
1607 expected = old;
1608 old = qatomic_cmpxchg(&client->refcount, expected, expected - 1);
1609 } while (old != expected);
1610
1611 return true;
1612 }
1613
client_close(NBDClient * client,bool negotiated)1614 static void client_close(NBDClient *client, bool negotiated)
1615 {
1616 assert(qemu_in_main_thread());
1617
1618 WITH_QEMU_LOCK_GUARD(&client->lock) {
1619 if (client->closing) {
1620 return;
1621 }
1622
1623 client->closing = true;
1624 }
1625
1626 /* Force requests to finish. They will drop their own references,
1627 * then we'll close the socket and free the NBDClient.
1628 */
1629 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
1630 NULL);
1631
1632 /* Also tell the client, so that they release their reference. */
1633 if (client->close_fn) {
1634 client->close_fn(client, negotiated);
1635 }
1636 }
1637
1638 /* Runs in export AioContext with client->lock held */
nbd_request_get(NBDClient * client)1639 static NBDRequestData *nbd_request_get(NBDClient *client)
1640 {
1641 NBDRequestData *req;
1642
1643 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
1644 client->nb_requests++;
1645
1646 req = g_new0(NBDRequestData, 1);
1647 req->client = client;
1648 return req;
1649 }
1650
1651 /* Runs in export AioContext with client->lock held */
nbd_request_put(NBDRequestData * req)1652 static void nbd_request_put(NBDRequestData *req)
1653 {
1654 NBDClient *client = req->client;
1655
1656 if (req->data) {
1657 qemu_vfree(req->data);
1658 }
1659 g_free(req);
1660
1661 client->nb_requests--;
1662
1663 if (client->quiescing && client->nb_requests == 0) {
1664 aio_wait_kick();
1665 }
1666
1667 nbd_client_receive_next_request(client);
1668 }
1669
blk_aio_attached(AioContext * ctx,void * opaque)1670 static void blk_aio_attached(AioContext *ctx, void *opaque)
1671 {
1672 NBDExport *exp = opaque;
1673 NBDClient *client;
1674
1675 assert(qemu_in_main_thread());
1676
1677 trace_nbd_blk_aio_attached(exp->name, ctx);
1678
1679 exp->common.ctx = ctx;
1680
1681 QTAILQ_FOREACH(client, &exp->clients, next) {
1682 WITH_QEMU_LOCK_GUARD(&client->lock) {
1683 assert(client->nb_requests == 0);
1684 assert(client->recv_coroutine == NULL);
1685 assert(client->send_coroutine == NULL);
1686 }
1687 }
1688 }
1689
blk_aio_detach(void * opaque)1690 static void blk_aio_detach(void *opaque)
1691 {
1692 NBDExport *exp = opaque;
1693
1694 assert(qemu_in_main_thread());
1695
1696 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx);
1697
1698 exp->common.ctx = NULL;
1699 }
1700
nbd_drained_begin(void * opaque)1701 static void nbd_drained_begin(void *opaque)
1702 {
1703 NBDExport *exp = opaque;
1704 NBDClient *client;
1705
1706 assert(qemu_in_main_thread());
1707
1708 QTAILQ_FOREACH(client, &exp->clients, next) {
1709 WITH_QEMU_LOCK_GUARD(&client->lock) {
1710 client->quiescing = true;
1711 }
1712 }
1713 }
1714
nbd_drained_end(void * opaque)1715 static void nbd_drained_end(void *opaque)
1716 {
1717 NBDExport *exp = opaque;
1718 NBDClient *client;
1719
1720 assert(qemu_in_main_thread());
1721
1722 QTAILQ_FOREACH(client, &exp->clients, next) {
1723 WITH_QEMU_LOCK_GUARD(&client->lock) {
1724 client->quiescing = false;
1725 nbd_client_receive_next_request(client);
1726 }
1727 }
1728 }
1729
1730 /* Runs in export AioContext */
nbd_wake_read_bh(void * opaque)1731 static void nbd_wake_read_bh(void *opaque)
1732 {
1733 NBDClient *client = opaque;
1734 qio_channel_wake_read(client->ioc);
1735 }
1736
nbd_drained_poll(void * opaque)1737 static bool nbd_drained_poll(void *opaque)
1738 {
1739 NBDExport *exp = opaque;
1740 NBDClient *client;
1741
1742 assert(qemu_in_main_thread());
1743
1744 QTAILQ_FOREACH(client, &exp->clients, next) {
1745 WITH_QEMU_LOCK_GUARD(&client->lock) {
1746 if (client->nb_requests != 0) {
1747 /*
1748 * If there's a coroutine waiting for a request on nbd_read_eof()
1749 * enter it here so we don't depend on the client to wake it up.
1750 *
1751 * Schedule a BH in the export AioContext to avoid missing the
1752 * wake up due to the race between qio_channel_wake_read() and
1753 * qio_channel_yield().
1754 */
1755 if (client->recv_coroutine != NULL && client->read_yielding) {
1756 aio_bh_schedule_oneshot(nbd_export_aio_context(client->exp),
1757 nbd_wake_read_bh, client);
1758 }
1759
1760 return true;
1761 }
1762 }
1763 }
1764
1765 return false;
1766 }
1767
nbd_eject_notifier(Notifier * n,void * data)1768 static void nbd_eject_notifier(Notifier *n, void *data)
1769 {
1770 NBDExport *exp = container_of(n, NBDExport, eject_notifier);
1771
1772 assert(qemu_in_main_thread());
1773
1774 blk_exp_request_shutdown(&exp->common);
1775 }
1776
nbd_export_set_on_eject_blk(BlockExport * exp,BlockBackend * blk)1777 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk)
1778 {
1779 NBDExport *nbd_exp = container_of(exp, NBDExport, common);
1780 assert(exp->drv == &blk_exp_nbd);
1781 assert(nbd_exp->eject_notifier_blk == NULL);
1782
1783 blk_ref(blk);
1784 nbd_exp->eject_notifier_blk = blk;
1785 nbd_exp->eject_notifier.notify = nbd_eject_notifier;
1786 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier);
1787 }
1788
1789 static const BlockDevOps nbd_block_ops = {
1790 .drained_begin = nbd_drained_begin,
1791 .drained_end = nbd_drained_end,
1792 .drained_poll = nbd_drained_poll,
1793 };
1794
nbd_export_create(BlockExport * blk_exp,BlockExportOptions * exp_args,Error ** errp)1795 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args,
1796 Error **errp)
1797 {
1798 NBDExport *exp = container_of(blk_exp, NBDExport, common);
1799 BlockExportOptionsNbd *arg = &exp_args->u.nbd;
1800 const char *name = arg->name ?: exp_args->node_name;
1801 BlockBackend *blk = blk_exp->blk;
1802 int64_t size;
1803 uint64_t perm, shared_perm;
1804 bool readonly = !exp_args->writable;
1805 BlockDirtyBitmapOrStrList *bitmaps;
1806 size_t i;
1807 int ret;
1808
1809 GLOBAL_STATE_CODE();
1810 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
1811
1812 if (!nbd_server_is_running()) {
1813 error_setg(errp, "NBD server not running");
1814 return -EINVAL;
1815 }
1816
1817 if (strlen(name) > NBD_MAX_STRING_SIZE) {
1818 error_setg(errp, "export name '%s' too long", name);
1819 return -EINVAL;
1820 }
1821
1822 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) {
1823 error_setg(errp, "description '%s' too long", arg->description);
1824 return -EINVAL;
1825 }
1826
1827 if (nbd_export_find(name)) {
1828 error_setg(errp, "NBD server already has export named '%s'", name);
1829 return -EEXIST;
1830 }
1831
1832 size = blk_getlength(blk);
1833 if (size < 0) {
1834 error_setg_errno(errp, -size,
1835 "Failed to determine the NBD export's length");
1836 return size;
1837 }
1838
1839 /* Don't allow resize while the NBD server is running, otherwise we don't
1840 * care what happens with the node. */
1841 blk_get_perm(blk, &perm, &shared_perm);
1842 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp);
1843 if (ret < 0) {
1844 return ret;
1845 }
1846
1847 QTAILQ_INIT(&exp->clients);
1848 exp->name = g_strdup(name);
1849 exp->description = g_strdup(arg->description);
1850 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH |
1851 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE);
1852
1853 if (nbd_server_max_connections() != 1) {
1854 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
1855 }
1856 if (readonly) {
1857 exp->nbdflags |= NBD_FLAG_READ_ONLY;
1858 } else {
1859 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES |
1860 NBD_FLAG_SEND_FAST_ZERO);
1861 }
1862 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
1863
1864 bdrv_graph_rdlock_main_loop();
1865
1866 for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) {
1867 exp->nr_export_bitmaps++;
1868 }
1869 exp->export_bitmaps = g_new0(BdrvDirtyBitmap *, exp->nr_export_bitmaps);
1870 for (i = 0, bitmaps = arg->bitmaps; bitmaps;
1871 i++, bitmaps = bitmaps->next)
1872 {
1873 const char *bitmap;
1874 BlockDriverState *bs = blk_bs(blk);
1875 BdrvDirtyBitmap *bm = NULL;
1876
1877 switch (bitmaps->value->type) {
1878 case QTYPE_QSTRING:
1879 bitmap = bitmaps->value->u.local;
1880 while (bs) {
1881 bm = bdrv_find_dirty_bitmap(bs, bitmap);
1882 if (bm != NULL) {
1883 break;
1884 }
1885
1886 bs = bdrv_filter_or_cow_bs(bs);
1887 }
1888
1889 if (bm == NULL) {
1890 ret = -ENOENT;
1891 error_setg(errp, "Bitmap '%s' is not found",
1892 bitmaps->value->u.local);
1893 goto fail;
1894 }
1895
1896 if (readonly && bdrv_is_writable(bs) &&
1897 bdrv_dirty_bitmap_enabled(bm)) {
1898 ret = -EINVAL;
1899 error_setg(errp, "Enabled bitmap '%s' incompatible with "
1900 "readonly export", bitmap);
1901 goto fail;
1902 }
1903 break;
1904 case QTYPE_QDICT:
1905 bitmap = bitmaps->value->u.external.name;
1906 bm = block_dirty_bitmap_lookup(bitmaps->value->u.external.node,
1907 bitmap, NULL, errp);
1908 if (!bm) {
1909 ret = -ENOENT;
1910 goto fail;
1911 }
1912 break;
1913 default:
1914 abort();
1915 }
1916
1917 assert(bm);
1918
1919 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
1920 ret = -EINVAL;
1921 goto fail;
1922 }
1923
1924 exp->export_bitmaps[i] = bm;
1925 assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE);
1926 }
1927
1928 /* Mark bitmaps busy in a separate loop, to simplify roll-back concerns. */
1929 for (i = 0; i < exp->nr_export_bitmaps; i++) {
1930 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true);
1931 }
1932
1933 exp->allocation_depth = arg->allocation_depth;
1934
1935 /*
1936 * We need to inhibit request queuing in the block layer to ensure we can
1937 * be properly quiesced when entering a drained section, as our coroutines
1938 * servicing pending requests might enter blk_pread().
1939 */
1940 blk_set_disable_request_queuing(blk, true);
1941
1942 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
1943
1944 blk_set_dev_ops(blk, &nbd_block_ops, exp);
1945
1946 QTAILQ_INSERT_TAIL(&exports, exp, next);
1947
1948 bdrv_graph_rdunlock_main_loop();
1949
1950 return 0;
1951
1952 fail:
1953 bdrv_graph_rdunlock_main_loop();
1954 g_free(exp->export_bitmaps);
1955 g_free(exp->name);
1956 g_free(exp->description);
1957 return ret;
1958 }
1959
nbd_export_find(const char * name)1960 NBDExport *nbd_export_find(const char *name)
1961 {
1962 NBDExport *exp;
1963 QTAILQ_FOREACH(exp, &exports, next) {
1964 if (strcmp(name, exp->name) == 0) {
1965 return exp;
1966 }
1967 }
1968
1969 return NULL;
1970 }
1971
1972 AioContext *
nbd_export_aio_context(NBDExport * exp)1973 nbd_export_aio_context(NBDExport *exp)
1974 {
1975 return exp->common.ctx;
1976 }
1977
nbd_export_request_shutdown(BlockExport * blk_exp)1978 static void nbd_export_request_shutdown(BlockExport *blk_exp)
1979 {
1980 NBDExport *exp = container_of(blk_exp, NBDExport, common);
1981 NBDClient *client, *next;
1982
1983 blk_exp_ref(&exp->common);
1984 /*
1985 * TODO: Should we expand QMP BlockExportRemoveMode enum to allow a
1986 * close mode that stops advertising the export to new clients but
1987 * still permits existing clients to run to completion? Because of
1988 * that possibility, nbd_export_close() can be called more than
1989 * once on an export.
1990 */
1991 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
1992 client_close(client, true);
1993 }
1994 if (exp->name) {
1995 g_free(exp->name);
1996 exp->name = NULL;
1997 QTAILQ_REMOVE(&exports, exp, next);
1998 }
1999 blk_exp_unref(&exp->common);
2000 }
2001
nbd_export_delete(BlockExport * blk_exp)2002 static void nbd_export_delete(BlockExport *blk_exp)
2003 {
2004 size_t i;
2005 NBDExport *exp = container_of(blk_exp, NBDExport, common);
2006
2007 assert(exp->name == NULL);
2008 assert(QTAILQ_EMPTY(&exp->clients));
2009
2010 g_free(exp->description);
2011 exp->description = NULL;
2012
2013 if (exp->eject_notifier_blk) {
2014 notifier_remove(&exp->eject_notifier);
2015 blk_unref(exp->eject_notifier_blk);
2016 }
2017 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached,
2018 blk_aio_detach, exp);
2019 blk_set_disable_request_queuing(exp->common.blk, false);
2020
2021 for (i = 0; i < exp->nr_export_bitmaps; i++) {
2022 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], false);
2023 }
2024 }
2025
2026 const BlockExportDriver blk_exp_nbd = {
2027 .type = BLOCK_EXPORT_TYPE_NBD,
2028 .instance_size = sizeof(NBDExport),
2029 .supports_inactive = true,
2030 .create = nbd_export_create,
2031 .delete = nbd_export_delete,
2032 .request_shutdown = nbd_export_request_shutdown,
2033 };
2034
nbd_co_send_iov(NBDClient * client,struct iovec * iov,unsigned niov,Error ** errp)2035 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov,
2036 unsigned niov, Error **errp)
2037 {
2038 int ret;
2039
2040 g_assert(qemu_in_coroutine());
2041 qemu_co_mutex_lock(&client->send_lock);
2042 client->send_coroutine = qemu_coroutine_self();
2043
2044 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0;
2045
2046 client->send_coroutine = NULL;
2047 qemu_co_mutex_unlock(&client->send_lock);
2048
2049 return ret;
2050 }
2051
set_be_simple_reply(NBDSimpleReply * reply,uint64_t error,uint64_t cookie)2052 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
2053 uint64_t cookie)
2054 {
2055 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC);
2056 stl_be_p(&reply->error, error);
2057 stq_be_p(&reply->cookie, cookie);
2058 }
2059
nbd_co_send_simple_reply(NBDClient * client,NBDRequest * request,uint32_t error,void * data,uint64_t len,Error ** errp)2060 static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client,
2061 NBDRequest *request,
2062 uint32_t error,
2063 void *data,
2064 uint64_t len,
2065 Error **errp)
2066 {
2067 NBDSimpleReply reply;
2068 int nbd_err = system_errno_to_nbd_errno(error);
2069 struct iovec iov[] = {
2070 {.iov_base = &reply, .iov_len = sizeof(reply)},
2071 {.iov_base = data, .iov_len = len}
2072 };
2073
2074 assert(!len || !nbd_err);
2075 assert(len <= NBD_MAX_BUFFER_SIZE);
2076 assert(client->mode < NBD_MODE_STRUCTURED ||
2077 (client->mode == NBD_MODE_STRUCTURED &&
2078 request->type != NBD_CMD_READ));
2079 trace_nbd_co_send_simple_reply(request->cookie, nbd_err,
2080 nbd_err_lookup(nbd_err), len);
2081 set_be_simple_reply(&reply, nbd_err, request->cookie);
2082
2083 return nbd_co_send_iov(client, iov, 2, errp);
2084 }
2085
2086 /*
2087 * Prepare the header of a reply chunk for network transmission.
2088 *
2089 * On input, @iov is partially initialized: iov[0].iov_base must point
2090 * to an uninitialized NBDReply, while the remaining @niov elements
2091 * (if any) must be ready for transmission. This function then
2092 * populates iov[0] for transmission.
2093 */
set_be_chunk(NBDClient * client,struct iovec * iov,size_t niov,uint16_t flags,uint16_t type,NBDRequest * request)2094 static inline void set_be_chunk(NBDClient *client, struct iovec *iov,
2095 size_t niov, uint16_t flags, uint16_t type,
2096 NBDRequest *request)
2097 {
2098 size_t i, length = 0;
2099
2100 for (i = 1; i < niov; i++) {
2101 length += iov[i].iov_len;
2102 }
2103 assert(length <= NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData));
2104
2105 if (client->mode >= NBD_MODE_EXTENDED) {
2106 NBDExtendedReplyChunk *chunk = iov->iov_base;
2107
2108 iov[0].iov_len = sizeof(*chunk);
2109 stl_be_p(&chunk->magic, NBD_EXTENDED_REPLY_MAGIC);
2110 stw_be_p(&chunk->flags, flags);
2111 stw_be_p(&chunk->type, type);
2112 stq_be_p(&chunk->cookie, request->cookie);
2113 stq_be_p(&chunk->offset, request->from);
2114 stq_be_p(&chunk->length, length);
2115 } else {
2116 NBDStructuredReplyChunk *chunk = iov->iov_base;
2117
2118 iov[0].iov_len = sizeof(*chunk);
2119 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
2120 stw_be_p(&chunk->flags, flags);
2121 stw_be_p(&chunk->type, type);
2122 stq_be_p(&chunk->cookie, request->cookie);
2123 stl_be_p(&chunk->length, length);
2124 }
2125 }
2126
nbd_co_send_chunk_done(NBDClient * client,NBDRequest * request,Error ** errp)2127 static int coroutine_fn nbd_co_send_chunk_done(NBDClient *client,
2128 NBDRequest *request,
2129 Error **errp)
2130 {
2131 NBDReply hdr;
2132 struct iovec iov[] = {
2133 {.iov_base = &hdr},
2134 };
2135
2136 trace_nbd_co_send_chunk_done(request->cookie);
2137 set_be_chunk(client, iov, 1, NBD_REPLY_FLAG_DONE,
2138 NBD_REPLY_TYPE_NONE, request);
2139 return nbd_co_send_iov(client, iov, 1, errp);
2140 }
2141
nbd_co_send_chunk_read(NBDClient * client,NBDRequest * request,uint64_t offset,void * data,uint64_t size,bool final,Error ** errp)2142 static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client,
2143 NBDRequest *request,
2144 uint64_t offset,
2145 void *data,
2146 uint64_t size,
2147 bool final,
2148 Error **errp)
2149 {
2150 NBDReply hdr;
2151 NBDStructuredReadData chunk;
2152 struct iovec iov[] = {
2153 {.iov_base = &hdr},
2154 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
2155 {.iov_base = data, .iov_len = size}
2156 };
2157
2158 assert(size && size <= NBD_MAX_BUFFER_SIZE);
2159 trace_nbd_co_send_chunk_read(request->cookie, offset, data, size);
2160 set_be_chunk(client, iov, 3, final ? NBD_REPLY_FLAG_DONE : 0,
2161 NBD_REPLY_TYPE_OFFSET_DATA, request);
2162 stq_be_p(&chunk.offset, offset);
2163
2164 return nbd_co_send_iov(client, iov, 3, errp);
2165 }
2166
nbd_co_send_chunk_error(NBDClient * client,NBDRequest * request,uint32_t error,const char * msg,Error ** errp)2167 static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client,
2168 NBDRequest *request,
2169 uint32_t error,
2170 const char *msg,
2171 Error **errp)
2172 {
2173 NBDReply hdr;
2174 NBDStructuredError chunk;
2175 int nbd_err = system_errno_to_nbd_errno(error);
2176 struct iovec iov[] = {
2177 {.iov_base = &hdr},
2178 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
2179 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
2180 };
2181
2182 assert(nbd_err);
2183 trace_nbd_co_send_chunk_error(request->cookie, nbd_err,
2184 nbd_err_lookup(nbd_err), msg ? msg : "");
2185 set_be_chunk(client, iov, 3, NBD_REPLY_FLAG_DONE,
2186 NBD_REPLY_TYPE_ERROR, request);
2187 stl_be_p(&chunk.error, nbd_err);
2188 stw_be_p(&chunk.message_length, iov[2].iov_len);
2189
2190 return nbd_co_send_iov(client, iov, 3, errp);
2191 }
2192
2193 /* Do a sparse read and send the structured reply to the client.
2194 * Returns -errno if sending fails. blk_co_block_status_above() failure is
2195 * reported to the client, at which point this function succeeds.
2196 */
nbd_co_send_sparse_read(NBDClient * client,NBDRequest * request,uint64_t offset,uint8_t * data,uint64_t size,Error ** errp)2197 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
2198 NBDRequest *request,
2199 uint64_t offset,
2200 uint8_t *data,
2201 uint64_t size,
2202 Error **errp)
2203 {
2204 int ret = 0;
2205 NBDExport *exp = client->exp;
2206 size_t progress = 0;
2207
2208 assert(size <= NBD_MAX_BUFFER_SIZE);
2209 while (progress < size) {
2210 int64_t pnum;
2211 int status = blk_co_block_status_above(exp->common.blk, NULL,
2212 offset + progress,
2213 size - progress, &pnum, NULL,
2214 NULL);
2215 bool final;
2216
2217 if (status < 0) {
2218 char *msg = g_strdup_printf("unable to check for holes: %s",
2219 strerror(-status));
2220
2221 ret = nbd_co_send_chunk_error(client, request, -status, msg, errp);
2222 g_free(msg);
2223 return ret;
2224 }
2225 assert(pnum && pnum <= size - progress);
2226 final = progress + pnum == size;
2227 if (status & BDRV_BLOCK_ZERO) {
2228 NBDReply hdr;
2229 NBDStructuredReadHole chunk;
2230 struct iovec iov[] = {
2231 {.iov_base = &hdr},
2232 {.iov_base = &chunk, .iov_len = sizeof(chunk)},
2233 };
2234
2235 trace_nbd_co_send_chunk_read_hole(request->cookie,
2236 offset + progress, pnum);
2237 set_be_chunk(client, iov, 2,
2238 final ? NBD_REPLY_FLAG_DONE : 0,
2239 NBD_REPLY_TYPE_OFFSET_HOLE, request);
2240 stq_be_p(&chunk.offset, offset + progress);
2241 stl_be_p(&chunk.length, pnum);
2242 ret = nbd_co_send_iov(client, iov, 2, errp);
2243 } else {
2244 ret = blk_co_pread(exp->common.blk, offset + progress, pnum,
2245 data + progress, 0);
2246 if (ret < 0) {
2247 error_setg_errno(errp, -ret, "reading from file failed");
2248 break;
2249 }
2250 ret = nbd_co_send_chunk_read(client, request, offset + progress,
2251 data + progress, pnum, final, errp);
2252 }
2253
2254 if (ret < 0) {
2255 break;
2256 }
2257 progress += pnum;
2258 }
2259 return ret;
2260 }
2261
2262 typedef struct NBDExtentArray {
2263 NBDExtent64 *extents;
2264 unsigned int nb_alloc;
2265 unsigned int count;
2266 uint64_t total_length;
2267 bool extended;
2268 bool can_add;
2269 bool converted_to_be;
2270 } NBDExtentArray;
2271
nbd_extent_array_new(unsigned int nb_alloc,NBDMode mode)2272 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc,
2273 NBDMode mode)
2274 {
2275 NBDExtentArray *ea = g_new0(NBDExtentArray, 1);
2276
2277 assert(mode >= NBD_MODE_STRUCTURED);
2278 ea->nb_alloc = nb_alloc;
2279 ea->extents = g_new(NBDExtent64, nb_alloc);
2280 ea->extended = mode >= NBD_MODE_EXTENDED;
2281 ea->can_add = true;
2282
2283 return ea;
2284 }
2285
nbd_extent_array_free(NBDExtentArray * ea)2286 static void nbd_extent_array_free(NBDExtentArray *ea)
2287 {
2288 g_free(ea->extents);
2289 g_free(ea);
2290 }
G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray,nbd_extent_array_free)2291 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free)
2292
2293 /* Further modifications of the array after conversion are abandoned */
2294 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea)
2295 {
2296 int i;
2297
2298 assert(!ea->converted_to_be);
2299 assert(ea->extended);
2300 ea->can_add = false;
2301 ea->converted_to_be = true;
2302
2303 for (i = 0; i < ea->count; i++) {
2304 ea->extents[i].length = cpu_to_be64(ea->extents[i].length);
2305 ea->extents[i].flags = cpu_to_be64(ea->extents[i].flags);
2306 }
2307 }
2308
2309 /* Further modifications of the array after conversion are abandoned */
nbd_extent_array_convert_to_narrow(NBDExtentArray * ea)2310 static NBDExtent32 *nbd_extent_array_convert_to_narrow(NBDExtentArray *ea)
2311 {
2312 int i;
2313 NBDExtent32 *extents = g_new(NBDExtent32, ea->count);
2314
2315 assert(!ea->converted_to_be);
2316 assert(!ea->extended);
2317 ea->can_add = false;
2318 ea->converted_to_be = true;
2319
2320 for (i = 0; i < ea->count; i++) {
2321 assert((ea->extents[i].length | ea->extents[i].flags) <= UINT32_MAX);
2322 extents[i].length = cpu_to_be32(ea->extents[i].length);
2323 extents[i].flags = cpu_to_be32(ea->extents[i].flags);
2324 }
2325
2326 return extents;
2327 }
2328
2329 /*
2330 * Add extent to NBDExtentArray. If extent can't be added (no available space),
2331 * return -1.
2332 * For safety, when returning -1 for the first time, .can_add is set to false,
2333 * and further calls to nbd_extent_array_add() will crash.
2334 * (this avoids the situation where a caller ignores failure to add one extent,
2335 * where adding another extent that would squash into the last array entry
2336 * would result in an incorrect range reported to the client)
2337 */
nbd_extent_array_add(NBDExtentArray * ea,uint64_t length,uint32_t flags)2338 static int nbd_extent_array_add(NBDExtentArray *ea,
2339 uint64_t length, uint32_t flags)
2340 {
2341 assert(ea->can_add);
2342
2343 if (!length) {
2344 return 0;
2345 }
2346 if (!ea->extended) {
2347 assert(length <= UINT32_MAX);
2348 }
2349
2350 /* Extend previous extent if flags are the same */
2351 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) {
2352 uint64_t sum = length + ea->extents[ea->count - 1].length;
2353
2354 /*
2355 * sum cannot overflow: the block layer bounds image size at
2356 * 2^63, and ea->extents[].length comes from the block layer.
2357 */
2358 assert(sum >= length);
2359 if (sum <= UINT32_MAX || ea->extended) {
2360 ea->extents[ea->count - 1].length = sum;
2361 ea->total_length += length;
2362 return 0;
2363 }
2364 }
2365
2366 if (ea->count >= ea->nb_alloc) {
2367 ea->can_add = false;
2368 return -1;
2369 }
2370
2371 ea->total_length += length;
2372 ea->extents[ea->count] = (NBDExtent64) {.length = length, .flags = flags};
2373 ea->count++;
2374
2375 return 0;
2376 }
2377
blockstatus_to_extents(BlockBackend * blk,uint64_t offset,uint64_t bytes,NBDExtentArray * ea)2378 static int coroutine_fn blockstatus_to_extents(BlockBackend *blk,
2379 uint64_t offset, uint64_t bytes,
2380 NBDExtentArray *ea)
2381 {
2382 while (bytes) {
2383 uint32_t flags;
2384 int64_t num;
2385 int ret = blk_co_block_status_above(blk, NULL, offset, bytes, &num,
2386 NULL, NULL);
2387
2388 if (ret < 0) {
2389 return ret;
2390 }
2391
2392 flags = (ret & BDRV_BLOCK_DATA ? 0 : NBD_STATE_HOLE) |
2393 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
2394
2395 if (nbd_extent_array_add(ea, num, flags) < 0) {
2396 return 0;
2397 }
2398
2399 offset += num;
2400 bytes -= num;
2401 }
2402
2403 return 0;
2404 }
2405
blockalloc_to_extents(BlockBackend * blk,uint64_t offset,uint64_t bytes,NBDExtentArray * ea)2406 static int coroutine_fn blockalloc_to_extents(BlockBackend *blk,
2407 uint64_t offset, uint64_t bytes,
2408 NBDExtentArray *ea)
2409 {
2410 while (bytes) {
2411 int64_t num;
2412 int ret = blk_co_is_allocated_above(blk, NULL, false, offset, bytes,
2413 &num);
2414
2415 if (ret < 0) {
2416 return ret;
2417 }
2418
2419 if (nbd_extent_array_add(ea, num, ret) < 0) {
2420 return 0;
2421 }
2422
2423 offset += num;
2424 bytes -= num;
2425 }
2426
2427 return 0;
2428 }
2429
2430 /*
2431 * nbd_co_send_extents
2432 *
2433 * @ea is converted to BE by the function
2434 * @last controls whether NBD_REPLY_FLAG_DONE is sent.
2435 */
2436 static int coroutine_fn
nbd_co_send_extents(NBDClient * client,NBDRequest * request,NBDExtentArray * ea,bool last,uint32_t context_id,Error ** errp)2437 nbd_co_send_extents(NBDClient *client, NBDRequest *request, NBDExtentArray *ea,
2438 bool last, uint32_t context_id, Error **errp)
2439 {
2440 NBDReply hdr;
2441 NBDStructuredMeta meta;
2442 NBDExtendedMeta meta_ext;
2443 g_autofree NBDExtent32 *extents = NULL;
2444 uint16_t type;
2445 struct iovec iov[] = { {.iov_base = &hdr}, {0}, {0} };
2446
2447 if (client->mode >= NBD_MODE_EXTENDED) {
2448 type = NBD_REPLY_TYPE_BLOCK_STATUS_EXT;
2449
2450 iov[1].iov_base = &meta_ext;
2451 iov[1].iov_len = sizeof(meta_ext);
2452 stl_be_p(&meta_ext.context_id, context_id);
2453 stl_be_p(&meta_ext.count, ea->count);
2454
2455 nbd_extent_array_convert_to_be(ea);
2456 iov[2].iov_base = ea->extents;
2457 iov[2].iov_len = ea->count * sizeof(ea->extents[0]);
2458 } else {
2459 type = NBD_REPLY_TYPE_BLOCK_STATUS;
2460
2461 iov[1].iov_base = &meta;
2462 iov[1].iov_len = sizeof(meta);
2463 stl_be_p(&meta.context_id, context_id);
2464
2465 extents = nbd_extent_array_convert_to_narrow(ea);
2466 iov[2].iov_base = extents;
2467 iov[2].iov_len = ea->count * sizeof(extents[0]);
2468 }
2469
2470 trace_nbd_co_send_extents(request->cookie, ea->count, context_id,
2471 ea->total_length, last);
2472 set_be_chunk(client, iov, 3, last ? NBD_REPLY_FLAG_DONE : 0, type,
2473 request);
2474
2475 return nbd_co_send_iov(client, iov, 3, errp);
2476 }
2477
2478 /* Get block status from the exported device and send it to the client */
2479 static int
nbd_co_send_block_status(NBDClient * client,NBDRequest * request,BlockBackend * blk,uint64_t offset,uint64_t length,bool dont_fragment,bool last,uint32_t context_id,Error ** errp)2480 coroutine_fn nbd_co_send_block_status(NBDClient *client, NBDRequest *request,
2481 BlockBackend *blk, uint64_t offset,
2482 uint64_t length, bool dont_fragment,
2483 bool last, uint32_t context_id,
2484 Error **errp)
2485 {
2486 int ret;
2487 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
2488 g_autoptr(NBDExtentArray) ea =
2489 nbd_extent_array_new(nb_extents, client->mode);
2490
2491 if (context_id == NBD_META_ID_BASE_ALLOCATION) {
2492 ret = blockstatus_to_extents(blk, offset, length, ea);
2493 } else {
2494 ret = blockalloc_to_extents(blk, offset, length, ea);
2495 }
2496 if (ret < 0) {
2497 return nbd_co_send_chunk_error(client, request, -ret,
2498 "can't get block status", errp);
2499 }
2500
2501 return nbd_co_send_extents(client, request, ea, last, context_id, errp);
2502 }
2503
2504 /* Populate @ea from a dirty bitmap. */
bitmap_to_extents(BdrvDirtyBitmap * bitmap,uint64_t offset,uint64_t length,NBDExtentArray * es)2505 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap,
2506 uint64_t offset, uint64_t length,
2507 NBDExtentArray *es)
2508 {
2509 int64_t start, dirty_start, dirty_count;
2510 int64_t end = offset + length;
2511 bool full = false;
2512 int64_t bound = es->extended ? INT64_MAX : INT32_MAX;
2513
2514 bdrv_dirty_bitmap_lock(bitmap);
2515
2516 for (start = offset;
2517 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, bound,
2518 &dirty_start, &dirty_count);
2519 start = dirty_start + dirty_count)
2520 {
2521 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) ||
2522 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0))
2523 {
2524 full = true;
2525 break;
2526 }
2527 }
2528
2529 if (!full) {
2530 /* last non dirty extent, nothing to do if array is now full */
2531 (void) nbd_extent_array_add(es, end - start, 0);
2532 }
2533
2534 bdrv_dirty_bitmap_unlock(bitmap);
2535 }
2536
nbd_co_send_bitmap(NBDClient * client,NBDRequest * request,BdrvDirtyBitmap * bitmap,uint64_t offset,uint64_t length,bool dont_fragment,bool last,uint32_t context_id,Error ** errp)2537 static int coroutine_fn nbd_co_send_bitmap(NBDClient *client,
2538 NBDRequest *request,
2539 BdrvDirtyBitmap *bitmap,
2540 uint64_t offset,
2541 uint64_t length, bool dont_fragment,
2542 bool last, uint32_t context_id,
2543 Error **errp)
2544 {
2545 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
2546 g_autoptr(NBDExtentArray) ea =
2547 nbd_extent_array_new(nb_extents, client->mode);
2548
2549 bitmap_to_extents(bitmap, offset, length, ea);
2550
2551 return nbd_co_send_extents(client, request, ea, last, context_id, errp);
2552 }
2553
2554 /*
2555 * nbd_co_block_status_payload_read
2556 * Called when a client wants a subset of negotiated contexts via a
2557 * BLOCK_STATUS payload. Check the payload for valid length and
2558 * contents. On success, return 0 with request updated to effective
2559 * length. If request was invalid but all payload consumed, return 0
2560 * with request->len and request->contexts->count set to 0 (which will
2561 * trigger an appropriate NBD_EINVAL response later on). Return
2562 * negative errno if the payload was not fully consumed.
2563 */
2564 static int
nbd_co_block_status_payload_read(NBDClient * client,NBDRequest * request,Error ** errp)2565 nbd_co_block_status_payload_read(NBDClient *client, NBDRequest *request,
2566 Error **errp)
2567 {
2568 uint64_t payload_len = request->len;
2569 g_autofree char *buf = NULL;
2570 size_t count, i, nr_bitmaps;
2571 uint32_t id;
2572
2573 if (payload_len > NBD_MAX_BUFFER_SIZE) {
2574 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)",
2575 request->len, NBD_MAX_BUFFER_SIZE);
2576 return -EINVAL;
2577 }
2578
2579 assert(client->contexts.exp == client->exp);
2580 nr_bitmaps = client->exp->nr_export_bitmaps;
2581 request->contexts = g_new0(NBDMetaContexts, 1);
2582 request->contexts->exp = client->exp;
2583
2584 if (payload_len % sizeof(uint32_t) ||
2585 payload_len < sizeof(NBDBlockStatusPayload) ||
2586 payload_len > (sizeof(NBDBlockStatusPayload) +
2587 sizeof(id) * client->contexts.count)) {
2588 goto skip;
2589 }
2590
2591 buf = g_malloc(payload_len);
2592 if (nbd_read(client->ioc, buf, payload_len,
2593 "CMD_BLOCK_STATUS data", errp) < 0) {
2594 return -EIO;
2595 }
2596 trace_nbd_co_receive_request_payload_received(request->cookie,
2597 payload_len);
2598 request->contexts->bitmaps = g_new0(bool, nr_bitmaps);
2599 count = (payload_len - sizeof(NBDBlockStatusPayload)) / sizeof(id);
2600 payload_len = 0;
2601
2602 for (i = 0; i < count; i++) {
2603 id = ldl_be_p(buf + sizeof(NBDBlockStatusPayload) + sizeof(id) * i);
2604 if (id == NBD_META_ID_BASE_ALLOCATION) {
2605 if (!client->contexts.base_allocation ||
2606 request->contexts->base_allocation) {
2607 goto skip;
2608 }
2609 request->contexts->base_allocation = true;
2610 } else if (id == NBD_META_ID_ALLOCATION_DEPTH) {
2611 if (!client->contexts.allocation_depth ||
2612 request->contexts->allocation_depth) {
2613 goto skip;
2614 }
2615 request->contexts->allocation_depth = true;
2616 } else {
2617 unsigned idx = id - NBD_META_ID_DIRTY_BITMAP;
2618
2619 if (idx >= nr_bitmaps || !client->contexts.bitmaps[idx] ||
2620 request->contexts->bitmaps[idx]) {
2621 goto skip;
2622 }
2623 request->contexts->bitmaps[idx] = true;
2624 }
2625 }
2626
2627 request->len = ldq_be_p(buf);
2628 request->contexts->count = count;
2629 return 0;
2630
2631 skip:
2632 trace_nbd_co_receive_block_status_payload_compliance(request->from,
2633 request->len);
2634 request->len = request->contexts->count = 0;
2635 return nbd_drop(client->ioc, payload_len, errp);
2636 }
2637
2638 /* nbd_co_receive_request
2639 * Collect a client request. Return 0 if request looks valid, -EIO to drop
2640 * connection right away, -EAGAIN to indicate we were interrupted and the
2641 * channel should be quiesced, and any other negative value to report an error
2642 * to the client (although the caller may still need to disconnect after
2643 * reporting the error).
2644 */
nbd_co_receive_request(NBDRequestData * req,NBDRequest * request,Error ** errp)2645 static int coroutine_fn nbd_co_receive_request(NBDRequestData *req,
2646 NBDRequest *request,
2647 Error **errp)
2648 {
2649 NBDClient *client = req->client;
2650 bool extended_with_payload;
2651 bool check_length = false;
2652 bool check_rofs = false;
2653 bool allocate_buffer = false;
2654 bool payload_okay = false;
2655 uint64_t payload_len = 0;
2656 int valid_flags = NBD_CMD_FLAG_FUA;
2657 int ret;
2658
2659 g_assert(qemu_in_coroutine());
2660 ret = nbd_receive_request(client, request, errp);
2661 if (ret < 0) {
2662 return ret;
2663 }
2664
2665 trace_nbd_co_receive_request_decode_type(request->cookie, request->type,
2666 nbd_cmd_lookup(request->type));
2667 extended_with_payload = client->mode >= NBD_MODE_EXTENDED &&
2668 request->flags & NBD_CMD_FLAG_PAYLOAD_LEN;
2669 if (extended_with_payload) {
2670 payload_len = request->len;
2671 check_length = true;
2672 }
2673
2674 switch (request->type) {
2675 case NBD_CMD_DISC:
2676 /* Special case: we're going to disconnect without a reply,
2677 * whether or not flags, from, or len are bogus */
2678 req->complete = true;
2679 return -EIO;
2680
2681 case NBD_CMD_READ:
2682 if (client->mode >= NBD_MODE_STRUCTURED) {
2683 valid_flags |= NBD_CMD_FLAG_DF;
2684 }
2685 check_length = true;
2686 allocate_buffer = true;
2687 break;
2688
2689 case NBD_CMD_WRITE:
2690 if (client->mode >= NBD_MODE_EXTENDED) {
2691 if (!extended_with_payload) {
2692 /* The client is noncompliant. Trace it, but proceed. */
2693 trace_nbd_co_receive_ext_payload_compliance(request->from,
2694 request->len);
2695 }
2696 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN;
2697 }
2698 payload_okay = true;
2699 payload_len = request->len;
2700 check_length = true;
2701 allocate_buffer = true;
2702 check_rofs = true;
2703 break;
2704
2705 case NBD_CMD_FLUSH:
2706 break;
2707
2708 case NBD_CMD_TRIM:
2709 check_rofs = true;
2710 break;
2711
2712 case NBD_CMD_CACHE:
2713 check_length = true;
2714 break;
2715
2716 case NBD_CMD_WRITE_ZEROES:
2717 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO;
2718 check_rofs = true;
2719 break;
2720
2721 case NBD_CMD_BLOCK_STATUS:
2722 if (extended_with_payload) {
2723 ret = nbd_co_block_status_payload_read(client, request, errp);
2724 if (ret < 0) {
2725 return ret;
2726 }
2727 /* payload now consumed */
2728 check_length = false;
2729 payload_len = 0;
2730 valid_flags |= NBD_CMD_FLAG_PAYLOAD_LEN;
2731 } else {
2732 request->contexts = &client->contexts;
2733 }
2734 valid_flags |= NBD_CMD_FLAG_REQ_ONE;
2735 break;
2736
2737 default:
2738 /* Unrecognized, will fail later */
2739 ;
2740 }
2741
2742 /* Payload and buffer handling. */
2743 if (!payload_len) {
2744 req->complete = true;
2745 }
2746 if (check_length && request->len > NBD_MAX_BUFFER_SIZE) {
2747 /* READ, WRITE, CACHE */
2748 error_setg(errp, "len (%" PRIu64 ") is larger than max len (%u)",
2749 request->len, NBD_MAX_BUFFER_SIZE);
2750 return -EINVAL;
2751 }
2752 if (payload_len && !payload_okay) {
2753 /*
2754 * For now, we don't support payloads on other commands; but
2755 * we can keep the connection alive by ignoring the payload.
2756 * We will fail the command later with NBD_EINVAL for the use
2757 * of an unsupported flag (and not for access beyond bounds).
2758 */
2759 assert(request->type != NBD_CMD_WRITE);
2760 request->len = 0;
2761 }
2762 if (allocate_buffer) {
2763 /* READ, WRITE */
2764 req->data = blk_try_blockalign(client->exp->common.blk,
2765 request->len);
2766 if (req->data == NULL) {
2767 error_setg(errp, "No memory");
2768 return -ENOMEM;
2769 }
2770 }
2771 if (payload_len) {
2772 if (payload_okay) {
2773 /* WRITE */
2774 assert(req->data);
2775 ret = nbd_read(client->ioc, req->data, payload_len,
2776 "CMD_WRITE data", errp);
2777 } else {
2778 ret = nbd_drop(client->ioc, payload_len, errp);
2779 }
2780 if (ret < 0) {
2781 return -EIO;
2782 }
2783 req->complete = true;
2784 trace_nbd_co_receive_request_payload_received(request->cookie,
2785 payload_len);
2786 }
2787
2788 /* Sanity checks. */
2789 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && check_rofs) {
2790 /* WRITE, TRIM, WRITE_ZEROES */
2791 error_setg(errp, "Export is read-only");
2792 return -EROFS;
2793 }
2794 if (request->from > client->exp->size ||
2795 request->len > client->exp->size - request->from) {
2796 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu64
2797 ", Size: %" PRIu64, request->from, request->len,
2798 client->exp->size);
2799 return (request->type == NBD_CMD_WRITE ||
2800 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
2801 }
2802 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len,
2803 client->check_align)) {
2804 /*
2805 * The block layer gracefully handles unaligned requests, but
2806 * it's still worth tracing client non-compliance
2807 */
2808 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type),
2809 request->from,
2810 request->len,
2811 client->check_align);
2812 }
2813 if (request->flags & ~valid_flags) {
2814 error_setg(errp, "unsupported flags for command %s (got 0x%x)",
2815 nbd_cmd_lookup(request->type), request->flags);
2816 return -EINVAL;
2817 }
2818
2819 return 0;
2820 }
2821
2822 /* Send simple reply without a payload, or a structured error
2823 * @error_msg is ignored if @ret >= 0
2824 * Returns 0 if connection is still live, -errno on failure to talk to client
2825 */
nbd_send_generic_reply(NBDClient * client,NBDRequest * request,int ret,const char * error_msg,Error ** errp)2826 static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
2827 NBDRequest *request,
2828 int ret,
2829 const char *error_msg,
2830 Error **errp)
2831 {
2832 if (client->mode >= NBD_MODE_STRUCTURED && ret < 0) {
2833 return nbd_co_send_chunk_error(client, request, -ret, error_msg, errp);
2834 } else if (client->mode >= NBD_MODE_EXTENDED) {
2835 return nbd_co_send_chunk_done(client, request, errp);
2836 } else {
2837 return nbd_co_send_simple_reply(client, request, ret < 0 ? -ret : 0,
2838 NULL, 0, errp);
2839 }
2840 }
2841
2842 /* Handle NBD_CMD_READ request.
2843 * Return -errno if sending fails. Other errors are reported directly to the
2844 * client as an error reply. */
nbd_do_cmd_read(NBDClient * client,NBDRequest * request,uint8_t * data,Error ** errp)2845 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
2846 uint8_t *data, Error **errp)
2847 {
2848 int ret;
2849 NBDExport *exp = client->exp;
2850
2851 assert(request->type == NBD_CMD_READ);
2852 assert(request->len <= NBD_MAX_BUFFER_SIZE);
2853
2854 /* XXX: NBD Protocol only documents use of FUA with WRITE */
2855 if (request->flags & NBD_CMD_FLAG_FUA) {
2856 ret = blk_co_flush(exp->common.blk);
2857 if (ret < 0) {
2858 return nbd_send_generic_reply(client, request, ret,
2859 "flush failed", errp);
2860 }
2861 }
2862
2863 if (client->mode >= NBD_MODE_STRUCTURED &&
2864 !(request->flags & NBD_CMD_FLAG_DF) && request->len)
2865 {
2866 return nbd_co_send_sparse_read(client, request, request->from,
2867 data, request->len, errp);
2868 }
2869
2870 ret = blk_co_pread(exp->common.blk, request->from, request->len, data, 0);
2871 if (ret < 0) {
2872 return nbd_send_generic_reply(client, request, ret,
2873 "reading from file failed", errp);
2874 }
2875
2876 if (client->mode >= NBD_MODE_STRUCTURED) {
2877 if (request->len) {
2878 return nbd_co_send_chunk_read(client, request, request->from, data,
2879 request->len, true, errp);
2880 } else {
2881 return nbd_co_send_chunk_done(client, request, errp);
2882 }
2883 } else {
2884 return nbd_co_send_simple_reply(client, request, 0,
2885 data, request->len, errp);
2886 }
2887 }
2888
2889 /*
2890 * nbd_do_cmd_cache
2891 *
2892 * Handle NBD_CMD_CACHE request.
2893 * Return -errno if sending fails. Other errors are reported directly to the
2894 * client as an error reply.
2895 */
nbd_do_cmd_cache(NBDClient * client,NBDRequest * request,Error ** errp)2896 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request,
2897 Error **errp)
2898 {
2899 int ret;
2900 NBDExport *exp = client->exp;
2901
2902 assert(request->type == NBD_CMD_CACHE);
2903 assert(request->len <= NBD_MAX_BUFFER_SIZE);
2904
2905 ret = blk_co_preadv(exp->common.blk, request->from, request->len,
2906 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH);
2907
2908 return nbd_send_generic_reply(client, request, ret,
2909 "caching data failed", errp);
2910 }
2911
2912 /* Handle NBD request.
2913 * Return -errno if sending fails. Other errors are reported directly to the
2914 * client as an error reply. */
nbd_handle_request(NBDClient * client,NBDRequest * request,uint8_t * data,Error ** errp)2915 static coroutine_fn int nbd_handle_request(NBDClient *client,
2916 NBDRequest *request,
2917 uint8_t *data, Error **errp)
2918 {
2919 int ret;
2920 int flags;
2921 NBDExport *exp = client->exp;
2922 char *msg;
2923 size_t i;
2924 bool inactive;
2925
2926 WITH_GRAPH_RDLOCK_GUARD() {
2927 inactive = bdrv_is_inactive(blk_bs(exp->common.blk));
2928 if (inactive) {
2929 switch (request->type) {
2930 case NBD_CMD_READ:
2931 /* These commands are allowed on inactive nodes */
2932 break;
2933 default:
2934 /* Return an error for the rest */
2935 return nbd_send_generic_reply(client, request, -EPERM,
2936 "export is inactive", errp);
2937 }
2938 }
2939 }
2940
2941 switch (request->type) {
2942 case NBD_CMD_CACHE:
2943 return nbd_do_cmd_cache(client, request, errp);
2944
2945 case NBD_CMD_READ:
2946 return nbd_do_cmd_read(client, request, data, errp);
2947
2948 case NBD_CMD_WRITE:
2949 flags = 0;
2950 if (request->flags & NBD_CMD_FLAG_FUA) {
2951 flags |= BDRV_REQ_FUA;
2952 }
2953 assert(request->len <= NBD_MAX_BUFFER_SIZE);
2954 ret = blk_co_pwrite(exp->common.blk, request->from, request->len, data,
2955 flags);
2956 return nbd_send_generic_reply(client, request, ret,
2957 "writing to file failed", errp);
2958
2959 case NBD_CMD_WRITE_ZEROES:
2960 flags = 0;
2961 if (request->flags & NBD_CMD_FLAG_FUA) {
2962 flags |= BDRV_REQ_FUA;
2963 }
2964 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) {
2965 flags |= BDRV_REQ_MAY_UNMAP;
2966 }
2967 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) {
2968 flags |= BDRV_REQ_NO_FALLBACK;
2969 }
2970 ret = blk_co_pwrite_zeroes(exp->common.blk, request->from, request->len,
2971 flags);
2972 return nbd_send_generic_reply(client, request, ret,
2973 "writing to file failed", errp);
2974
2975 case NBD_CMD_DISC:
2976 /* unreachable, thanks to special case in nbd_co_receive_request() */
2977 abort();
2978
2979 case NBD_CMD_FLUSH:
2980 ret = blk_co_flush(exp->common.blk);
2981 return nbd_send_generic_reply(client, request, ret,
2982 "flush failed", errp);
2983
2984 case NBD_CMD_TRIM:
2985 ret = blk_co_pdiscard(exp->common.blk, request->from, request->len);
2986 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) {
2987 ret = blk_co_flush(exp->common.blk);
2988 }
2989 return nbd_send_generic_reply(client, request, ret,
2990 "discard failed", errp);
2991
2992 case NBD_CMD_BLOCK_STATUS:
2993 assert(request->contexts);
2994 assert(client->mode >= NBD_MODE_EXTENDED ||
2995 request->len <= UINT32_MAX);
2996 if (request->contexts->count) {
2997 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
2998 int contexts_remaining = request->contexts->count;
2999
3000 if (!request->len) {
3001 return nbd_send_generic_reply(client, request, -EINVAL,
3002 "need non-zero length", errp);
3003 }
3004 if (request->contexts->base_allocation) {
3005 ret = nbd_co_send_block_status(client, request,
3006 exp->common.blk,
3007 request->from,
3008 request->len, dont_fragment,
3009 !--contexts_remaining,
3010 NBD_META_ID_BASE_ALLOCATION,
3011 errp);
3012 if (ret < 0) {
3013 return ret;
3014 }
3015 }
3016
3017 if (request->contexts->allocation_depth) {
3018 ret = nbd_co_send_block_status(client, request,
3019 exp->common.blk,
3020 request->from, request->len,
3021 dont_fragment,
3022 !--contexts_remaining,
3023 NBD_META_ID_ALLOCATION_DEPTH,
3024 errp);
3025 if (ret < 0) {
3026 return ret;
3027 }
3028 }
3029
3030 assert(request->contexts->exp == client->exp);
3031 for (i = 0; i < client->exp->nr_export_bitmaps; i++) {
3032 if (!request->contexts->bitmaps[i]) {
3033 continue;
3034 }
3035 ret = nbd_co_send_bitmap(client, request,
3036 client->exp->export_bitmaps[i],
3037 request->from, request->len,
3038 dont_fragment, !--contexts_remaining,
3039 NBD_META_ID_DIRTY_BITMAP + i, errp);
3040 if (ret < 0) {
3041 return ret;
3042 }
3043 }
3044
3045 assert(!contexts_remaining);
3046
3047 return 0;
3048 } else if (client->contexts.count) {
3049 return nbd_send_generic_reply(client, request, -EINVAL,
3050 "CMD_BLOCK_STATUS payload not valid",
3051 errp);
3052 } else {
3053 return nbd_send_generic_reply(client, request, -EINVAL,
3054 "CMD_BLOCK_STATUS not negotiated",
3055 errp);
3056 }
3057
3058 default:
3059 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
3060 request->type);
3061 ret = nbd_send_generic_reply(client, request, -EINVAL, msg,
3062 errp);
3063 g_free(msg);
3064 return ret;
3065 }
3066 }
3067
3068 /* Owns a reference to the NBDClient passed as opaque. */
nbd_trip(void * opaque)3069 static coroutine_fn void nbd_trip(void *opaque)
3070 {
3071 NBDRequestData *req = opaque;
3072 NBDClient *client = req->client;
3073 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */
3074 int ret;
3075 Error *local_err = NULL;
3076
3077 /*
3078 * Note that nbd_client_put() and client_close() must be called from the
3079 * main loop thread. Use aio_co_reschedule_self() to switch AioContext
3080 * before calling these functions.
3081 */
3082
3083 trace_nbd_trip();
3084
3085 qemu_mutex_lock(&client->lock);
3086
3087 if (client->closing) {
3088 goto done;
3089 }
3090
3091 if (client->quiescing) {
3092 /*
3093 * We're switching between AIO contexts. Don't attempt to receive a new
3094 * request and kick the main context which may be waiting for us.
3095 */
3096 client->recv_coroutine = NULL;
3097 aio_wait_kick();
3098 goto done;
3099 }
3100
3101 /*
3102 * nbd_co_receive_request() returns -EAGAIN when nbd_drained_begin() has
3103 * set client->quiescing but by the time we get back nbd_drained_end() may
3104 * have already cleared client->quiescing. In that case we try again
3105 * because nothing else will spawn an nbd_trip() coroutine until we set
3106 * client->recv_coroutine = NULL further down.
3107 */
3108 do {
3109 assert(client->recv_coroutine == qemu_coroutine_self());
3110 qemu_mutex_unlock(&client->lock);
3111 ret = nbd_co_receive_request(req, &request, &local_err);
3112 qemu_mutex_lock(&client->lock);
3113 } while (ret == -EAGAIN && !client->quiescing);
3114
3115 client->recv_coroutine = NULL;
3116
3117 if (client->closing) {
3118 /*
3119 * The client may be closed when we are blocked in
3120 * nbd_co_receive_request()
3121 */
3122 goto done;
3123 }
3124
3125 if (ret == -EAGAIN) {
3126 goto done;
3127 }
3128
3129 nbd_client_receive_next_request(client);
3130
3131 if (ret == -EIO) {
3132 goto disconnect;
3133 }
3134
3135 qemu_mutex_unlock(&client->lock);
3136 qio_channel_set_cork(client->ioc, true);
3137
3138 if (ret < 0) {
3139 /* It wasn't -EIO, so, according to nbd_co_receive_request()
3140 * semantics, we should return the error to the client. */
3141 Error *export_err = local_err;
3142
3143 local_err = NULL;
3144 ret = nbd_send_generic_reply(client, &request, -EINVAL,
3145 error_get_pretty(export_err), &local_err);
3146 error_free(export_err);
3147 } else {
3148 ret = nbd_handle_request(client, &request, req->data, &local_err);
3149 }
3150 if (request.contexts && request.contexts != &client->contexts) {
3151 assert(request.type == NBD_CMD_BLOCK_STATUS);
3152 g_free(request.contexts->bitmaps);
3153 g_free(request.contexts);
3154 }
3155
3156 qio_channel_set_cork(client->ioc, false);
3157 qemu_mutex_lock(&client->lock);
3158
3159 if (ret < 0) {
3160 error_prepend(&local_err, "Failed to send reply: ");
3161 goto disconnect;
3162 }
3163
3164 /*
3165 * We must disconnect after NBD_CMD_WRITE or BLOCK_STATUS with
3166 * payload if we did not read the payload.
3167 */
3168 if (!req->complete) {
3169 error_setg(&local_err, "Request handling failed in intermediate state");
3170 goto disconnect;
3171 }
3172
3173 done:
3174 nbd_request_put(req);
3175
3176 qemu_mutex_unlock(&client->lock);
3177
3178 if (!nbd_client_put_nonzero(client)) {
3179 aio_co_reschedule_self(qemu_get_aio_context());
3180 nbd_client_put(client);
3181 }
3182 return;
3183
3184 disconnect:
3185 if (local_err) {
3186 error_reportf_err(local_err, "Disconnect client, due to: ");
3187 }
3188
3189 nbd_request_put(req);
3190 qemu_mutex_unlock(&client->lock);
3191
3192 aio_co_reschedule_self(qemu_get_aio_context());
3193 client_close(client, true);
3194 nbd_client_put(client);
3195 }
3196
3197 /*
3198 * Runs in export AioContext and main loop thread. Caller must hold
3199 * client->lock.
3200 */
nbd_client_receive_next_request(NBDClient * client)3201 static void nbd_client_receive_next_request(NBDClient *client)
3202 {
3203 NBDRequestData *req;
3204
3205 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS &&
3206 !client->quiescing) {
3207 nbd_client_get(client);
3208 req = nbd_request_get(client);
3209 client->recv_coroutine = qemu_coroutine_create(nbd_trip, req);
3210 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine);
3211 }
3212 }
3213
nbd_handshake_timer_cb(void * opaque)3214 static void nbd_handshake_timer_cb(void *opaque)
3215 {
3216 QIOChannel *ioc = opaque;
3217
3218 trace_nbd_handshake_timer_cb();
3219 qio_channel_shutdown(ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
3220 }
3221
nbd_co_client_start(void * opaque)3222 static coroutine_fn void nbd_co_client_start(void *opaque)
3223 {
3224 NBDClient *client = opaque;
3225 Error *local_err = NULL;
3226 QEMUTimer *handshake_timer = NULL;
3227
3228 qemu_co_mutex_init(&client->send_lock);
3229
3230 /*
3231 * Create a timer to bound the time spent in negotiation. If the
3232 * timer expires, it is likely nbd_negotiate will fail because the
3233 * socket was shutdown.
3234 */
3235 if (client->handshake_max_secs > 0) {
3236 handshake_timer = aio_timer_new(qemu_get_aio_context(),
3237 QEMU_CLOCK_REALTIME,
3238 SCALE_NS,
3239 nbd_handshake_timer_cb,
3240 client->sioc);
3241 timer_mod(handshake_timer,
3242 qemu_clock_get_ns(QEMU_CLOCK_REALTIME) +
3243 client->handshake_max_secs * NANOSECONDS_PER_SECOND);
3244 }
3245
3246 if (nbd_negotiate(client, &local_err)) {
3247 if (local_err) {
3248 error_report_err(local_err);
3249 }
3250 timer_free(handshake_timer);
3251 client_close(client, false);
3252 return;
3253 }
3254
3255 timer_free(handshake_timer);
3256 WITH_QEMU_LOCK_GUARD(&client->lock) {
3257 nbd_client_receive_next_request(client);
3258 }
3259 }
3260
3261 /*
3262 * Create a new client listener using the given channel @sioc and @owner.
3263 * Begin servicing it in a coroutine. When the connection closes, call
3264 * @close_fn with an indication of whether the client completed negotiation
3265 * within @handshake_max_secs seconds (0 for unbounded).
3266 */
nbd_client_new(QIOChannelSocket * sioc,uint32_t handshake_max_secs,QCryptoTLSCreds * tlscreds,const char * tlsauthz,void (* close_fn)(NBDClient *,bool),void * owner)3267 void nbd_client_new(QIOChannelSocket *sioc,
3268 uint32_t handshake_max_secs,
3269 QCryptoTLSCreds *tlscreds,
3270 const char *tlsauthz,
3271 void (*close_fn)(NBDClient *, bool),
3272 void *owner)
3273 {
3274 NBDClient *client;
3275 Coroutine *co;
3276
3277 client = g_new0(NBDClient, 1);
3278 qemu_mutex_init(&client->lock);
3279 client->refcount = 1;
3280 client->tlscreds = tlscreds;
3281 if (tlscreds) {
3282 object_ref(OBJECT(client->tlscreds));
3283 }
3284 client->tlsauthz = g_strdup(tlsauthz);
3285 client->handshake_max_secs = handshake_max_secs;
3286 client->sioc = sioc;
3287 qio_channel_set_delay(QIO_CHANNEL(sioc), false);
3288 object_ref(OBJECT(client->sioc));
3289 client->ioc = QIO_CHANNEL(sioc);
3290 object_ref(OBJECT(client->ioc));
3291 client->close_fn = close_fn;
3292 client->owner = owner;
3293
3294 nbd_set_socket_send_buffer(sioc);
3295
3296 co = qemu_coroutine_create(nbd_co_client_start, client);
3297 qemu_coroutine_enter(co);
3298 }
3299
3300 void *
nbd_client_owner(NBDClient * client)3301 nbd_client_owner(NBDClient *client)
3302 {
3303 return client->owner;
3304 }
3305