-
Notifications
You must be signed in to change notification settings - Fork 5.3k
/
client.c
1494 lines (1327 loc) · 46.6 KB
/
client.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Copyright (C) 2016-2018 Red Hat, Inc.
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device Client Side
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "trace.h"
#include "nbd-internal.h"
#include "qemu/cutils.h"
/* Definitions for opaque data types */
static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
/* That's all folks */
/* Basic flow for negotiation
Server Client
Negotiate
or
Server Client
Negotiate #1
Option
Negotiate #2
----
followed by
Server Client
Request
Response
Request
Response
...
...
Request (type == 2)
*/
/* Send an option request.
*
* The request is for option @opt, with @data containing @len bytes of
* additional payload for the request (@len may be -1 to treat @data as
* a C string; and @data may be NULL if @len is 0).
* Return 0 if successful, -1 with errp set if it is impossible to
* continue. */
static int nbd_send_option_request(QIOChannel *ioc, uint32_t opt,
uint32_t len, const char *data,
Error **errp)
{
NBDOption req;
QEMU_BUILD_BUG_ON(sizeof(req) != 16);
if (len == -1) {
req.length = len = strlen(data);
}
trace_nbd_send_option_request(opt, nbd_opt_lookup(opt), len);
stq_be_p(&req.magic, NBD_OPTS_MAGIC);
stl_be_p(&req.option, opt);
stl_be_p(&req.length, len);
if (nbd_write(ioc, &req, sizeof(req), errp) < 0) {
error_prepend(errp, "Failed to send option request header: ");
return -1;
}
if (len && nbd_write(ioc, (char *) data, len, errp) < 0) {
error_prepend(errp, "Failed to send option request data: ");
return -1;
}
return 0;
}
/* Send NBD_OPT_ABORT as a courtesy to let the server know that we are
* not going to attempt further negotiation. */
static void nbd_send_opt_abort(QIOChannel *ioc)
{
/* Technically, a compliant server is supposed to reply to us; but
* older servers disconnected instead. At any rate, we're allowed
* to disconnect without waiting for the server reply, so we don't
* even care if the request makes it to the server, let alone
* waiting around for whether the server replies. */
nbd_send_option_request(ioc, NBD_OPT_ABORT, 0, NULL, NULL);
}
/* Receive the header of an option reply, which should match the given
* opt. Read through the length field, but NOT the length bytes of
* payload. Return 0 if successful, -1 with errp set if it is
* impossible to continue. */
static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
NBDOptionReply *reply, Error **errp)
{
QEMU_BUILD_BUG_ON(sizeof(*reply) != 20);
if (nbd_read(ioc, reply, sizeof(*reply), "option reply", errp) < 0) {
nbd_send_opt_abort(ioc);
return -1;
}
reply->magic = be64_to_cpu(reply->magic);
reply->option = be32_to_cpu(reply->option);
reply->type = be32_to_cpu(reply->type);
reply->length = be32_to_cpu(reply->length);
trace_nbd_receive_option_reply(reply->option, nbd_opt_lookup(reply->option),
reply->type, nbd_rep_lookup(reply->type),
reply->length);
if (reply->magic != NBD_REP_MAGIC) {
error_setg(errp, "Unexpected option reply magic");
nbd_send_opt_abort(ioc);
return -1;
}
if (reply->option != opt) {
error_setg(errp, "Unexpected option type %u (%s), expected %u (%s)",
reply->option, nbd_opt_lookup(reply->option),
opt, nbd_opt_lookup(opt));
nbd_send_opt_abort(ioc);
return -1;
}
return 0;
}
/* If reply represents success, return 1 without further action.
* If reply represents an error, consume the optional payload of
* the packet on ioc. Then return 0 for unsupported (so the client
* can fall back to other approaches), or -1 with errp set for other
* errors.
*/
static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply,
Error **errp)
{
char *msg = NULL;
int result = -1;
if (!(reply->type & (1 << 31))) {
return 1;
}
if (reply->length) {
if (reply->length > NBD_MAX_BUFFER_SIZE) {
error_setg(errp, "server error %" PRIu32
" (%s) message is too long",
reply->type, nbd_rep_lookup(reply->type));
goto cleanup;
}
msg = g_malloc(reply->length + 1);
if (nbd_read(ioc, msg, reply->length, NULL, errp) < 0) {
error_prepend(errp, "Failed to read option error %" PRIu32
" (%s) message: ",
reply->type, nbd_rep_lookup(reply->type));
goto cleanup;
}
msg[reply->length] = '\0';
trace_nbd_server_error_msg(reply->type,
nbd_reply_type_lookup(reply->type), msg);
}
switch (reply->type) {
case NBD_REP_ERR_UNSUP:
trace_nbd_reply_err_unsup(reply->option, nbd_opt_lookup(reply->option));
result = 0;
goto cleanup;
case NBD_REP_ERR_POLICY:
error_setg(errp, "Denied by server for option %" PRIu32 " (%s)",
reply->option, nbd_opt_lookup(reply->option));
break;
case NBD_REP_ERR_INVALID:
error_setg(errp, "Invalid parameters for option %" PRIu32 " (%s)",
reply->option, nbd_opt_lookup(reply->option));
break;
case NBD_REP_ERR_PLATFORM:
error_setg(errp, "Server lacks support for option %" PRIu32 " (%s)",
reply->option, nbd_opt_lookup(reply->option));
break;
case NBD_REP_ERR_TLS_REQD:
error_setg(errp, "TLS negotiation required before option %" PRIu32
" (%s)", reply->option, nbd_opt_lookup(reply->option));
break;
case NBD_REP_ERR_UNKNOWN:
error_setg(errp, "Requested export not available");
break;
case NBD_REP_ERR_SHUTDOWN:
error_setg(errp, "Server shutting down before option %" PRIu32 " (%s)",
reply->option, nbd_opt_lookup(reply->option));
break;
case NBD_REP_ERR_BLOCK_SIZE_REQD:
error_setg(errp, "Server requires INFO_BLOCK_SIZE for option %" PRIu32
" (%s)", reply->option, nbd_opt_lookup(reply->option));
break;
default:
error_setg(errp, "Unknown error code when asking for option %" PRIu32
" (%s)", reply->option, nbd_opt_lookup(reply->option));
break;
}
if (msg) {
error_append_hint(errp, "server reported: %s\n", msg);
}
cleanup:
g_free(msg);
if (result < 0) {
nbd_send_opt_abort(ioc);
}
return result;
}
/* nbd_receive_list:
* Process another portion of the NBD_OPT_LIST reply, populating any
* name received into *@name. If @description is non-NULL, and the
* server provided a description, that is also populated. The caller
* must eventually call g_free() on success.
* Returns 1 if name and description were set and iteration must continue,
* 0 if iteration is complete (including if OPT_LIST unsupported),
* -1 with @errp set if an unrecoverable error occurred.
*/
static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
Error **errp)
{
int ret = -1;
NBDOptionReply reply;
uint32_t len;
uint32_t namelen;
char *local_name = NULL;
char *local_desc = NULL;
int error;
if (nbd_receive_option_reply(ioc, NBD_OPT_LIST, &reply, errp) < 0) {
return -1;
}
error = nbd_handle_reply_err(ioc, &reply, errp);
if (error <= 0) {
return error;
}
len = reply.length;
if (reply.type == NBD_REP_ACK) {
if (len != 0) {
error_setg(errp, "length too long for option end");
nbd_send_opt_abort(ioc);
return -1;
}
return 0;
} else if (reply.type != NBD_REP_SERVER) {
error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)",
reply.type, nbd_rep_lookup(reply.type),
NBD_REP_SERVER, nbd_rep_lookup(NBD_REP_SERVER));
nbd_send_opt_abort(ioc);
return -1;
}
if (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
error_setg(errp, "incorrect option length %" PRIu32, len);
nbd_send_opt_abort(ioc);
return -1;
}
if (nbd_read32(ioc, &namelen, "option name length", errp) < 0) {
nbd_send_opt_abort(ioc);
return -1;
}
len -= sizeof(namelen);
if (len < namelen) {
error_setg(errp, "incorrect option name length");
nbd_send_opt_abort(ioc);
return -1;
}
local_name = g_malloc(namelen + 1);
if (nbd_read(ioc, local_name, namelen, "export name", errp) < 0) {
nbd_send_opt_abort(ioc);
goto out;
}
local_name[namelen] = '\0';
len -= namelen;
if (len) {
local_desc = g_malloc(len + 1);
if (nbd_read(ioc, local_desc, len, "export description", errp) < 0) {
nbd_send_opt_abort(ioc);
goto out;
}
local_desc[len] = '\0';
}
trace_nbd_receive_list(local_name, local_desc ?: "");
*name = local_name;
local_name = NULL;
if (description) {
*description = local_desc;
local_desc = NULL;
}
ret = 1;
out:
g_free(local_name);
g_free(local_desc);
return ret;
}
/*
* nbd_opt_info_or_go:
* Send option for NBD_OPT_INFO or NBD_OPT_GO and parse the reply.
* Returns -1 if the option proves the export @info->name cannot be
* used, 0 if the option is unsupported (fall back to NBD_OPT_LIST and
* NBD_OPT_EXPORT_NAME in that case), and > 0 if the export is good to
* go (with the rest of @info populated).
*/
static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt,
NBDExportInfo *info, Error **errp)
{
NBDOptionReply reply;
uint32_t len = strlen(info->name);
uint16_t type;
int error;
char *buf;
/* The protocol requires that the server send NBD_INFO_EXPORT with
* a non-zero flags (at least NBD_FLAG_HAS_FLAGS must be set); so
* flags still 0 is a witness of a broken server. */
info->flags = 0;
assert(opt == NBD_OPT_GO || opt == NBD_OPT_INFO);
trace_nbd_opt_info_go_start(nbd_opt_lookup(opt), info->name);
buf = g_malloc(4 + len + 2 + 2 * info->request_sizes + 1);
stl_be_p(buf, len);
memcpy(buf + 4, info->name, len);
/* At most one request, everything else up to server */
stw_be_p(buf + 4 + len, info->request_sizes);
if (info->request_sizes) {
stw_be_p(buf + 4 + len + 2, NBD_INFO_BLOCK_SIZE);
}
error = nbd_send_option_request(ioc, opt,
4 + len + 2 + 2 * info->request_sizes,
buf, errp);
g_free(buf);
if (error < 0) {
return -1;
}
while (1) {
if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) {
return -1;
}
error = nbd_handle_reply_err(ioc, &reply, errp);
if (error <= 0) {
return error;
}
len = reply.length;
if (reply.type == NBD_REP_ACK) {
/*
* Server is done sending info, and moved into transmission
* phase for NBD_OPT_GO, but make sure it sent flags
*/
if (len) {
error_setg(errp, "server sent invalid NBD_REP_ACK");
return -1;
}
if (!info->flags) {
error_setg(errp, "broken server omitted NBD_INFO_EXPORT");
return -1;
}
trace_nbd_opt_info_go_success(nbd_opt_lookup(opt));
return 1;
}
if (reply.type != NBD_REP_INFO) {
error_setg(errp, "unexpected reply type %u (%s), expected %u (%s)",
reply.type, nbd_rep_lookup(reply.type),
NBD_REP_INFO, nbd_rep_lookup(NBD_REP_INFO));
nbd_send_opt_abort(ioc);
return -1;
}
if (len < sizeof(type)) {
error_setg(errp, "NBD_REP_INFO length %" PRIu32 " is too short",
len);
nbd_send_opt_abort(ioc);
return -1;
}
if (nbd_read16(ioc, &type, "info type", errp) < 0) {
nbd_send_opt_abort(ioc);
return -1;
}
len -= sizeof(type);
switch (type) {
case NBD_INFO_EXPORT:
if (len != sizeof(info->size) + sizeof(info->flags)) {
error_setg(errp, "remaining export info len %" PRIu32
" is unexpected size", len);
nbd_send_opt_abort(ioc);
return -1;
}
if (nbd_read64(ioc, &info->size, "info size", errp) < 0) {
nbd_send_opt_abort(ioc);
return -1;
}
if (nbd_read16(ioc, &info->flags, "info flags", errp) < 0) {
nbd_send_opt_abort(ioc);
return -1;
}
if (info->min_block &&
!QEMU_IS_ALIGNED(info->size, info->min_block)) {
error_setg(errp, "export size %" PRIu64 "is not multiple of "
"minimum block size %" PRIu32, info->size,
info->min_block);
nbd_send_opt_abort(ioc);
return -1;
}
trace_nbd_receive_negotiate_size_flags(info->size, info->flags);
break;
case NBD_INFO_BLOCK_SIZE:
if (len != sizeof(info->min_block) * 3) {
error_setg(errp, "remaining export info len %" PRIu32
" is unexpected size", len);
nbd_send_opt_abort(ioc);
return -1;
}
if (nbd_read32(ioc, &info->min_block, "info minimum block size",
errp) < 0) {
nbd_send_opt_abort(ioc);
return -1;
}
if (!is_power_of_2(info->min_block)) {
error_setg(errp, "server minimum block size %" PRIu32
" is not a power of two", info->min_block);
nbd_send_opt_abort(ioc);
return -1;
}
if (nbd_read32(ioc, &info->opt_block, "info preferred block size",
errp) < 0)
{
nbd_send_opt_abort(ioc);
return -1;
}
if (!is_power_of_2(info->opt_block) ||
info->opt_block < info->min_block) {
error_setg(errp, "server preferred block size %" PRIu32
" is not valid", info->opt_block);
nbd_send_opt_abort(ioc);
return -1;
}
if (nbd_read32(ioc, &info->max_block, "info maximum block size",
errp) < 0)
{
nbd_send_opt_abort(ioc);
return -1;
}
if (info->max_block < info->min_block) {
error_setg(errp, "server maximum block size %" PRIu32
" is not valid", info->max_block);
nbd_send_opt_abort(ioc);
return -1;
}
trace_nbd_opt_info_block_size(info->min_block, info->opt_block,
info->max_block);
break;
default:
trace_nbd_opt_info_unknown(type, nbd_info_lookup(type));
if (nbd_drop(ioc, len, errp) < 0) {
error_prepend(errp, "Failed to read info payload: ");
nbd_send_opt_abort(ioc);
return -1;
}
break;
}
}
}
/* Return -1 on failure, 0 if wantname is an available export. */
static int nbd_receive_query_exports(QIOChannel *ioc,
const char *wantname,
Error **errp)
{
bool list_empty = true;
bool found_export = false;
trace_nbd_receive_query_exports_start(wantname);
if (nbd_send_option_request(ioc, NBD_OPT_LIST, 0, NULL, errp) < 0) {
return -1;
}
while (1) {
char *name;
int ret = nbd_receive_list(ioc, &name, NULL, errp);
if (ret < 0) {
/* Server gave unexpected reply */
return -1;
} else if (ret == 0) {
/* Done iterating. */
if (list_empty) {
/*
* We don't have enough context to tell a server that
* sent an empty list apart from a server that does
* not support the list command; but as this function
* is just used to trigger a nicer error message
* before trying NBD_OPT_EXPORT_NAME, assume the
* export is available.
*/
return 0;
} else if (!found_export) {
error_setg(errp, "No export with name '%s' available",
wantname);
nbd_send_opt_abort(ioc);
return -1;
}
trace_nbd_receive_query_exports_success(wantname);
return 0;
}
list_empty = false;
if (!strcmp(name, wantname)) {
found_export = true;
}
g_free(name);
}
}
/* nbd_request_simple_option: Send an option request, and parse the reply
* return 1 for successful negotiation,
* 0 if operation is unsupported,
* -1 with errp set for any other error
*/
static int nbd_request_simple_option(QIOChannel *ioc, int opt, Error **errp)
{
NBDOptionReply reply;
int error;
if (nbd_send_option_request(ioc, opt, 0, NULL, errp) < 0) {
return -1;
}
if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) {
return -1;
}
error = nbd_handle_reply_err(ioc, &reply, errp);
if (error <= 0) {
return error;
}
if (reply.type != NBD_REP_ACK) {
error_setg(errp, "Server answered option %d (%s) with unexpected "
"reply %" PRIu32 " (%s)", opt, nbd_opt_lookup(opt),
reply.type, nbd_rep_lookup(reply.type));
nbd_send_opt_abort(ioc);
return -1;
}
if (reply.length != 0) {
error_setg(errp, "Option %d ('%s') response length is %" PRIu32
" (it should be zero)", opt, nbd_opt_lookup(opt),
reply.length);
nbd_send_opt_abort(ioc);
return -1;
}
return 1;
}
static QIOChannel *nbd_receive_starttls(QIOChannel *ioc,
QCryptoTLSCreds *tlscreds,
const char *hostname, Error **errp)
{
int ret;
QIOChannelTLS *tioc;
struct NBDTLSHandshakeData data = { 0 };
ret = nbd_request_simple_option(ioc, NBD_OPT_STARTTLS, errp);
if (ret <= 0) {
if (ret == 0) {
error_setg(errp, "Server don't support STARTTLS option");
nbd_send_opt_abort(ioc);
}
return NULL;
}
trace_nbd_receive_starttls_new_client();
tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp);
if (!tioc) {
return NULL;
}
qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-client-tls");
data.loop = g_main_loop_new(g_main_context_default(), FALSE);
trace_nbd_receive_starttls_tls_handshake();
qio_channel_tls_handshake(tioc,
nbd_tls_handshake,
&data,
NULL,
NULL);
if (!data.complete) {
g_main_loop_run(data.loop);
}
g_main_loop_unref(data.loop);
if (data.error) {
error_propagate(errp, data.error);
object_unref(OBJECT(tioc));
return NULL;
}
return QIO_CHANNEL(tioc);
}
/*
* nbd_send_meta_query:
* Send 0 or 1 set/list meta context queries.
* Return 0 on success, -1 with errp set for any error
*/
static int nbd_send_meta_query(QIOChannel *ioc, uint32_t opt,
const char *export, const char *query,
Error **errp)
{
int ret;
uint32_t export_len = strlen(export);
uint32_t queries = !!query;
uint32_t query_len = 0;
uint32_t data_len;
char *data;
char *p;
data_len = sizeof(export_len) + export_len + sizeof(queries);
if (query) {
query_len = strlen(query);
data_len += sizeof(query_len) + query_len;
} else {
assert(opt == NBD_OPT_LIST_META_CONTEXT);
}
p = data = g_malloc(data_len);
trace_nbd_opt_meta_request(nbd_opt_lookup(opt), query ?: "(all)", export);
stl_be_p(p, export_len);
memcpy(p += sizeof(export_len), export, export_len);
stl_be_p(p += export_len, queries);
if (query) {
stl_be_p(p += sizeof(queries), query_len);
memcpy(p += sizeof(query_len), query, query_len);
}
ret = nbd_send_option_request(ioc, opt, data_len, data, errp);
g_free(data);
return ret;
}
/*
* nbd_receive_one_meta_context:
* Called in a loop to receive and trace one set/list meta context reply.
* Pass non-NULL @name or @id to collect results back to the caller, which
* must eventually call g_free().
* return 1 if name is set and iteration must continue,
* 0 if iteration is complete (including if option is unsupported),
* -1 with errp set for any error
*/
static int nbd_receive_one_meta_context(QIOChannel *ioc,
uint32_t opt,
char **name,
uint32_t *id,
Error **errp)
{
int ret;
NBDOptionReply reply;
char *local_name = NULL;
uint32_t local_id;
if (nbd_receive_option_reply(ioc, opt, &reply, errp) < 0) {
return -1;
}
ret = nbd_handle_reply_err(ioc, &reply, errp);
if (ret <= 0) {
return ret;
}
if (reply.type == NBD_REP_ACK) {
if (reply.length != 0) {
error_setg(errp, "Unexpected length to ACK response");
nbd_send_opt_abort(ioc);
return -1;
}
return 0;
} else if (reply.type != NBD_REP_META_CONTEXT) {
error_setg(errp, "Unexpected reply type %u (%s), expected %u (%s)",
reply.type, nbd_rep_lookup(reply.type),
NBD_REP_META_CONTEXT, nbd_rep_lookup(NBD_REP_META_CONTEXT));
nbd_send_opt_abort(ioc);
return -1;
}
if (reply.length <= sizeof(local_id) ||
reply.length > NBD_MAX_BUFFER_SIZE) {
error_setg(errp, "Failed to negotiate meta context, server "
"answered with unexpected length %" PRIu32,
reply.length);
nbd_send_opt_abort(ioc);
return -1;
}
if (nbd_read32(ioc, &local_id, "context id", errp) < 0) {
return -1;
}
reply.length -= sizeof(local_id);
local_name = g_malloc(reply.length + 1);
if (nbd_read(ioc, local_name, reply.length, "context name", errp) < 0) {
g_free(local_name);
return -1;
}
local_name[reply.length] = '\0';
trace_nbd_opt_meta_reply(nbd_opt_lookup(opt), local_name, local_id);
if (name) {
*name = local_name;
} else {
g_free(local_name);
}
if (id) {
*id = local_id;
}
return 1;
}
/*
* nbd_negotiate_simple_meta_context:
* Request the server to set the meta context for export @info->name
* using @info->x_dirty_bitmap with a fallback to "base:allocation",
* setting @info->context_id to the resulting id. Fail if the server
* responds with more than one context or with a context different
* than the query.
* return 1 for successful negotiation,
* 0 if operation is unsupported,
* -1 with errp set for any other error
*/
static int nbd_negotiate_simple_meta_context(QIOChannel *ioc,
NBDExportInfo *info,
Error **errp)
{
/*
* TODO: Removing the x_dirty_bitmap hack will mean refactoring
* this function to request and store ids for multiple contexts
* (both base:allocation and a dirty bitmap), at which point this
* function should lose the term _simple.
*/
int ret;
const char *context = info->x_dirty_bitmap ?: "base:allocation";
bool received = false;
char *name = NULL;
if (nbd_send_meta_query(ioc, NBD_OPT_SET_META_CONTEXT,
info->name, context, errp) < 0) {
return -1;
}
ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT,
&name, &info->context_id, errp);
if (ret < 0) {
return -1;
}
if (ret == 1) {
if (strcmp(context, name)) {
error_setg(errp, "Failed to negotiate meta context '%s', server "
"answered with different context '%s'", context,
name);
g_free(name);
nbd_send_opt_abort(ioc);
return -1;
}
g_free(name);
received = true;
ret = nbd_receive_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT,
NULL, NULL, errp);
if (ret < 0) {
return -1;
}
}
if (ret != 0) {
error_setg(errp, "Server answered with more than one context");
nbd_send_opt_abort(ioc);
return -1;
}
return received;
}
/*
* nbd_list_meta_contexts:
* Request the server to list all meta contexts for export @info->name.
* return 0 if list is complete (even if empty),
* -1 with errp set for any error
*/
static int nbd_list_meta_contexts(QIOChannel *ioc,
NBDExportInfo *info,
Error **errp)
{
int ret;
int seen_any = false;
int seen_qemu = false;
if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT,
info->name, NULL, errp) < 0) {
return -1;
}
while (1) {
char *context;
ret = nbd_receive_one_meta_context(ioc, NBD_OPT_LIST_META_CONTEXT,
&context, NULL, errp);
if (ret == 0 && seen_any && !seen_qemu) {
/*
* Work around qemu 3.0 bug: the server forgot to send
* "qemu:" replies to 0 queries. If we saw at least one
* reply (probably base:allocation), but none of them were
* qemu:, then run a more specific query to make sure.
*/
seen_qemu = true;
if (nbd_send_meta_query(ioc, NBD_OPT_LIST_META_CONTEXT,
info->name, "qemu:", errp) < 0) {
return -1;
}
continue;
}
if (ret <= 0) {
return ret;
}
seen_any = true;
seen_qemu |= strstart(context, "qemu:", NULL);
info->contexts = g_renew(char *, info->contexts, ++info->n_contexts);
info->contexts[info->n_contexts - 1] = context;
}
}
/*
* nbd_start_negotiate:
* Start the handshake to the server. After a positive return, the server
* is ready to accept additional NBD_OPT requests.
* Returns: negative errno: failure talking to server
* 0: server is oldstyle, must call nbd_negotiate_finish_oldstyle
* 1: server is newstyle, but can only accept EXPORT_NAME
* 2: server is newstyle, but lacks structured replies
* 3: server is newstyle and set up for structured replies
*/
static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
const char *hostname, QIOChannel **outioc,
bool structured_reply, bool *zeroes,
Error **errp)
{
uint64_t magic;
trace_nbd_start_negotiate(tlscreds, hostname ? hostname : "<null>");
if (zeroes) {
*zeroes = true;
}
if (outioc) {
*outioc = NULL;
}
if (tlscreds && !outioc) {
error_setg(errp, "Output I/O channel required for TLS");
return -EINVAL;
}
if (nbd_read64(ioc, &magic, "initial magic", errp) < 0) {
return -EINVAL;
}
trace_nbd_receive_negotiate_magic(magic);
if (magic != NBD_INIT_MAGIC) {
error_setg(errp, "Bad initial magic received: 0x%" PRIx64, magic);
return -EINVAL;
}
if (nbd_read64(ioc, &magic, "server magic", errp) < 0) {
return -EINVAL;
}
trace_nbd_receive_negotiate_magic(magic);
if (magic == NBD_OPTS_MAGIC) {
uint32_t clientflags = 0;
uint16_t globalflags;
bool fixedNewStyle = false;
if (nbd_read16(ioc, &globalflags, "server flags", errp) < 0) {
return -EINVAL;
}
trace_nbd_receive_negotiate_server_flags(globalflags);
if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
fixedNewStyle = true;
clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
}
if (globalflags & NBD_FLAG_NO_ZEROES) {
if (zeroes) {
*zeroes = false;
}
clientflags |= NBD_FLAG_C_NO_ZEROES;
}
/* client requested flags */
clientflags = cpu_to_be32(clientflags);
if (nbd_write(ioc, &clientflags, sizeof(clientflags), errp) < 0) {
error_prepend(errp, "Failed to send clientflags field: ");
return -EINVAL;
}
if (tlscreds) {
if (fixedNewStyle) {
*outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp);
if (!*outioc) {
return -EINVAL;
}
ioc = *outioc;
} else {
error_setg(errp, "Server does not support STARTTLS");
return -EINVAL;
}
}
if (fixedNewStyle) {
int result = 0;
if (structured_reply) {
result = nbd_request_simple_option(ioc,
NBD_OPT_STRUCTURED_REPLY,
errp);
if (result < 0) {
return -EINVAL;
}
}
return 2 + result;
} else {
return 1;
}
} else if (magic == NBD_CLIENT_MAGIC) {
if (tlscreds) {
error_setg(errp, "Server does not support STARTTLS");
return -EINVAL;
}
return 0;
} else {
error_setg(errp, "Bad server magic received: 0x%" PRIx64, magic);
return -EINVAL;
}
}
/*
* nbd_negotiate_finish_oldstyle:
* Populate @info with the size and export flags from an oldstyle server,
* but does not consume 124 bytes of reserved zero padding.
* Returns 0 on success, -1 with @errp set on failure
*/
static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info,
Error **errp)
{
uint32_t oldflags;
if (nbd_read64(ioc, &info->size, "export length", errp) < 0) {
return -EINVAL;
}
if (nbd_read32(ioc, &oldflags, "export flags", errp) < 0) {
return -EINVAL;
}
if (oldflags & ~0xffff) {
error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
return -EINVAL;
}
info->flags = oldflags;
return 0;
}
/*
* nbd_receive_negotiate:
* Connect to server, complete negotiation, and move into transmission phase.
* Returns: negative errno: failure talking to server
* 0: server is connected
*/