/
iscsi_tcp.c
2002 lines (1744 loc) · 52.4 KB
/
iscsi_tcp.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
/*
* iSCSI Initiator over TCP/IP Data-Path
*
* Copyright (C) 2004 Dmitry Yusupov
* Copyright (C) 2004 Alex Aizman
* Copyright (C) 2005 - 2006 Mike Christie
* Copyright (C) 2006 Red Hat, Inc. All rights reserved.
* maintained by open-iscsi@googlegroups.com
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*
* See the file COPYING included with this distribution for more details.
*
* Credits:
* Christoph Hellwig
* FUJITA Tomonori
* Arne Redlich
* Zhenyu Wang
*/
#include <linux/types.h>
#include <linux/list.h>
#include <linux/inet.h>
#include <linux/file.h>
#include <linux/blkdev.h>
#include <linux/crypto.h>
#include <linux/delay.h>
#include <linux/kfifo.h>
#include <linux/scatterlist.h>
#include <net/tcp.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi.h>
#include <scsi/scsi_transport_iscsi.h>
#include "iscsi_tcp.h"
MODULE_AUTHOR("Dmitry Yusupov <dmitry_yus@yahoo.com>, "
"Alex Aizman <itn780@yahoo.com>");
MODULE_DESCRIPTION("iSCSI/TCP data-path");
MODULE_LICENSE("GPL");
#undef DEBUG_TCP
#define DEBUG_ASSERT
#ifdef DEBUG_TCP
#define debug_tcp(fmt...) printk(KERN_INFO "tcp: " fmt)
#else
#define debug_tcp(fmt...)
#endif
#ifndef DEBUG_ASSERT
#ifdef BUG_ON
#undef BUG_ON
#endif
#define BUG_ON(expr)
#endif
static struct scsi_transport_template *iscsi_tcp_scsi_transport;
static struct scsi_host_template iscsi_sht;
static struct iscsi_transport iscsi_tcp_transport;
static unsigned int iscsi_max_lun = 512;
module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
struct iscsi_segment *segment);
/*
* Scatterlist handling: inside the iscsi_segment, we
* remember an index into the scatterlist, and set data/size
* to the current scatterlist entry. For highmem pages, we
* kmap as needed.
*
* Note that the page is unmapped when we return from
* TCP's data_ready handler, so we may end up mapping and
* unmapping the same page repeatedly. The whole reason
* for this is that we shouldn't keep the page mapped
* outside the softirq.
*/
/**
* iscsi_tcp_segment_init_sg - init indicated scatterlist entry
* @segment: the buffer object
* @sg: scatterlist
* @offset: byte offset into that sg entry
*
* This function sets up the segment so that subsequent
* data is copied to the indicated sg entry, at the given
* offset.
*/
static inline void
iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
struct scatterlist *sg, unsigned int offset)
{
segment->sg = sg;
segment->sg_offset = offset;
segment->size = min(sg->length - offset,
segment->total_size - segment->total_copied);
segment->data = NULL;
}
/**
* iscsi_tcp_segment_map - map the current S/G page
* @segment: iscsi_segment
* @recv: 1 if called from recv path
*
* We only need to possibly kmap data if scatter lists are being used,
* because the iscsi passthrough and internal IO paths will never use high
* mem pages.
*/
static inline void
iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
{
struct scatterlist *sg;
if (segment->data != NULL || !segment->sg)
return;
sg = segment->sg;
BUG_ON(segment->sg_mapped);
BUG_ON(sg->length == 0);
/*
* If the page count is greater than one it is ok to send
* to the network layer's zero copy send path. If not we
* have to go the slow sendmsg path. We always map for the
* recv path.
*/
if (page_count(sg_page(sg)) >= 1 && !recv)
return;
debug_tcp("iscsi_tcp_segment_map %s %p\n", recv ? "recv" : "xmit",
segment);
segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
}
static inline void
iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
{
debug_tcp("iscsi_tcp_segment_unmap %p\n", segment);
if (segment->sg_mapped) {
debug_tcp("iscsi_tcp_segment_unmap valid\n");
kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
segment->sg_mapped = NULL;
segment->data = NULL;
}
}
/*
* Splice the digest buffer into the buffer
*/
static inline void
iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
{
segment->data = digest;
segment->digest_len = ISCSI_DIGEST_SIZE;
segment->total_size += ISCSI_DIGEST_SIZE;
segment->size = ISCSI_DIGEST_SIZE;
segment->copied = 0;
segment->sg = NULL;
segment->hash = NULL;
}
/**
* iscsi_tcp_segment_done - check whether the segment is complete
* @segment: iscsi segment to check
* @recv: set to one of this is called from the recv path
* @copied: number of bytes copied
*
* Check if we're done receiving this segment. If the receive
* buffer is full but we expect more data, move on to the
* next entry in the scatterlist.
*
* If the amount of data we received isn't a multiple of 4,
* we will transparently receive the pad bytes, too.
*
* This function must be re-entrant.
*/
static inline int
iscsi_tcp_segment_done(struct iscsi_segment *segment, int recv, unsigned copied)
{
static unsigned char padbuf[ISCSI_PAD_LEN];
struct scatterlist sg;
unsigned int pad;
debug_tcp("copied %u %u size %u %s\n", segment->copied, copied,
segment->size, recv ? "recv" : "xmit");
if (segment->hash && copied) {
/*
* If a segment is kmapd we must unmap it before sending
* to the crypto layer since that will try to kmap it again.
*/
iscsi_tcp_segment_unmap(segment);
if (!segment->data) {
sg_init_table(&sg, 1);
sg_set_page(&sg, sg_page(segment->sg), copied,
segment->copied + segment->sg_offset +
segment->sg->offset);
} else
sg_init_one(&sg, segment->data + segment->copied,
copied);
crypto_hash_update(segment->hash, &sg, copied);
}
segment->copied += copied;
if (segment->copied < segment->size) {
iscsi_tcp_segment_map(segment, recv);
return 0;
}
segment->total_copied += segment->copied;
segment->copied = 0;
segment->size = 0;
/* Unmap the current scatterlist page, if there is one. */
iscsi_tcp_segment_unmap(segment);
/* Do we have more scatterlist entries? */
debug_tcp("total copied %u total size %u\n", segment->total_copied,
segment->total_size);
if (segment->total_copied < segment->total_size) {
/* Proceed to the next entry in the scatterlist. */
iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
0);
iscsi_tcp_segment_map(segment, recv);
BUG_ON(segment->size == 0);
return 0;
}
/* Do we need to handle padding? */
pad = iscsi_padding(segment->total_copied);
if (pad != 0) {
debug_tcp("consume %d pad bytes\n", pad);
segment->total_size += pad;
segment->size = pad;
segment->data = padbuf;
return 0;
}
/*
* Set us up for transferring the data digest. hdr digest
* is completely handled in hdr done function.
*/
if (segment->hash) {
crypto_hash_final(segment->hash, segment->digest);
iscsi_tcp_segment_splice_digest(segment,
recv ? segment->recv_digest : segment->digest);
return 0;
}
return 1;
}
/**
* iscsi_tcp_xmit_segment - transmit segment
* @tcp_conn: the iSCSI TCP connection
* @segment: the buffer to transmnit
*
* This function transmits as much of the buffer as
* the network layer will accept, and returns the number of
* bytes transmitted.
*
* If CRC hashing is enabled, the function will compute the
* hash as it goes. When the entire segment has been transmitted,
* it will retrieve the hash value and send it as well.
*/
static int
iscsi_tcp_xmit_segment(struct iscsi_tcp_conn *tcp_conn,
struct iscsi_segment *segment)
{
struct socket *sk = tcp_conn->sock;
unsigned int copied = 0;
int r = 0;
while (!iscsi_tcp_segment_done(segment, 0, r)) {
struct scatterlist *sg;
unsigned int offset, copy;
int flags = 0;
r = 0;
offset = segment->copied;
copy = segment->size - offset;
if (segment->total_copied + segment->size < segment->total_size)
flags |= MSG_MORE;
/* Use sendpage if we can; else fall back to sendmsg */
if (!segment->data) {
sg = segment->sg;
offset += segment->sg_offset + sg->offset;
r = tcp_conn->sendpage(sk, sg_page(sg), offset, copy,
flags);
} else {
struct msghdr msg = { .msg_flags = flags };
struct kvec iov = {
.iov_base = segment->data + offset,
.iov_len = copy
};
r = kernel_sendmsg(sk, &msg, &iov, 1, copy);
}
if (r < 0) {
iscsi_tcp_segment_unmap(segment);
if (copied || r == -EAGAIN)
break;
return r;
}
copied += r;
}
return copied;
}
/**
* iscsi_tcp_segment_recv - copy data to segment
* @tcp_conn: the iSCSI TCP connection
* @segment: the buffer to copy to
* @ptr: data pointer
* @len: amount of data available
*
* This function copies up to @len bytes to the
* given buffer, and returns the number of bytes
* consumed, which can actually be less than @len.
*
* If hash digest is enabled, the function will update the
* hash while copying.
* Combining these two operations doesn't buy us a lot (yet),
* but in the future we could implement combined copy+crc,
* just way we do for network layer checksums.
*/
static int
iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
struct iscsi_segment *segment, const void *ptr,
unsigned int len)
{
unsigned int copy = 0, copied = 0;
while (!iscsi_tcp_segment_done(segment, 1, copy)) {
if (copied == len) {
debug_tcp("iscsi_tcp_segment_recv copied %d bytes\n",
len);
break;
}
copy = min(len - copied, segment->size - segment->copied);
debug_tcp("iscsi_tcp_segment_recv copying %d\n", copy);
memcpy(segment->data + segment->copied, ptr + copied, copy);
copied += copy;
}
return copied;
}
static inline void
iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
unsigned char digest[ISCSI_DIGEST_SIZE])
{
struct scatterlist sg;
sg_init_one(&sg, hdr, hdrlen);
crypto_hash_digest(hash, &sg, hdrlen, digest);
}
static inline int
iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
struct iscsi_segment *segment)
{
if (!segment->digest_len)
return 1;
if (memcmp(segment->recv_digest, segment->digest,
segment->digest_len)) {
debug_scsi("digest mismatch\n");
return 0;
}
return 1;
}
/*
* Helper function to set up segment buffer
*/
static inline void
__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
iscsi_segment_done_fn_t *done, struct hash_desc *hash)
{
memset(segment, 0, sizeof(*segment));
segment->total_size = size;
segment->done = done;
if (hash) {
segment->hash = hash;
crypto_hash_init(hash);
}
}
static inline void
iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
size_t size, iscsi_segment_done_fn_t *done,
struct hash_desc *hash)
{
__iscsi_segment_init(segment, size, done, hash);
segment->data = data;
segment->size = size;
}
static inline int
iscsi_segment_seek_sg(struct iscsi_segment *segment,
struct scatterlist *sg_list, unsigned int sg_count,
unsigned int offset, size_t size,
iscsi_segment_done_fn_t *done, struct hash_desc *hash)
{
struct scatterlist *sg;
unsigned int i;
debug_scsi("iscsi_segment_seek_sg offset %u size %llu\n",
offset, size);
__iscsi_segment_init(segment, size, done, hash);
for_each_sg(sg_list, sg, sg_count, i) {
debug_scsi("sg %d, len %u offset %u\n", i, sg->length,
sg->offset);
if (offset < sg->length) {
iscsi_tcp_segment_init_sg(segment, sg, offset);
return 0;
}
offset -= sg->length;
}
return ISCSI_ERR_DATA_OFFSET;
}
/**
* iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
* @tcp_conn: iscsi connection to prep for
*
* This function always passes NULL for the hash argument, because when this
* function is called we do not yet know the final size of the header and want
* to delay the digest processing until we know that.
*/
static void
iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
{
debug_tcp("iscsi_tcp_hdr_recv_prep(%p%s)\n", tcp_conn,
tcp_conn->iscsi_conn->hdrdgst_en ? ", digest enabled" : "");
iscsi_segment_init_linear(&tcp_conn->in.segment,
tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
iscsi_tcp_hdr_recv_done, NULL);
}
/*
* Handle incoming reply to any other type of command
*/
static int
iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
struct iscsi_segment *segment)
{
struct iscsi_conn *conn = tcp_conn->iscsi_conn;
int rc = 0;
if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
return ISCSI_ERR_DATA_DGST;
rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
conn->data, tcp_conn->in.datalen);
if (rc)
return rc;
iscsi_tcp_hdr_recv_prep(tcp_conn);
return 0;
}
static void
iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
{
struct iscsi_conn *conn = tcp_conn->iscsi_conn;
struct hash_desc *rx_hash = NULL;
if (conn->datadgst_en)
rx_hash = &tcp_conn->rx_hash;
iscsi_segment_init_linear(&tcp_conn->in.segment,
conn->data, tcp_conn->in.datalen,
iscsi_tcp_data_recv_done, rx_hash);
}
/*
* must be called with session lock
*/
static void
iscsi_tcp_cleanup_task(struct iscsi_conn *conn, struct iscsi_task *task)
{
struct iscsi_tcp_task *tcp_task = task->dd_data;
struct iscsi_r2t_info *r2t;
/* nothing to do for mgmt tasks */
if (!task->sc)
return;
/* flush task's r2t queues */
while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
__kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
debug_scsi("iscsi_tcp_cleanup_task pending r2t dropped\n");
}
r2t = tcp_task->r2t;
if (r2t != NULL) {
__kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
tcp_task->r2t = NULL;
}
}
/**
* iscsi_data_in - SCSI Data-In Response processing
* @conn: iscsi connection
* @task: scsi command task
**/
static int
iscsi_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
{
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
struct iscsi_tcp_task *tcp_task = task->dd_data;
struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
int datasn = be32_to_cpu(rhdr->datasn);
unsigned total_in_length = scsi_in(task->sc)->length;
iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
if (tcp_conn->in.datalen == 0)
return 0;
if (tcp_task->exp_datasn != datasn) {
debug_tcp("%s: task->exp_datasn(%d) != rhdr->datasn(%d)\n",
__func__, tcp_task->exp_datasn, datasn);
return ISCSI_ERR_DATASN;
}
tcp_task->exp_datasn++;
tcp_task->data_offset = be32_to_cpu(rhdr->offset);
if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
debug_tcp("%s: data_offset(%d) + data_len(%d) > total_length_in(%d)\n",
__func__, tcp_task->data_offset,
tcp_conn->in.datalen, total_in_length);
return ISCSI_ERR_DATA_OFFSET;
}
conn->datain_pdus_cnt++;
return 0;
}
/**
* iscsi_solicit_data_init - initialize first Data-Out
* @conn: iscsi connection
* @task: scsi command task
* @r2t: R2T info
*
* Notes:
* Initialize first Data-Out within this R2T sequence and finds
* proper data_offset within this SCSI command.
*
* This function is called with connection lock taken.
**/
static void
iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_task *task,
struct iscsi_r2t_info *r2t)
{
struct iscsi_data *hdr;
hdr = &r2t->dtask.hdr;
memset(hdr, 0, sizeof(struct iscsi_data));
hdr->ttt = r2t->ttt;
hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
r2t->solicit_datasn++;
hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
memcpy(hdr->lun, task->hdr->lun, sizeof(hdr->lun));
hdr->itt = task->hdr->itt;
hdr->exp_statsn = r2t->exp_statsn;
hdr->offset = cpu_to_be32(r2t->data_offset);
if (r2t->data_length > conn->max_xmit_dlength) {
hton24(hdr->dlength, conn->max_xmit_dlength);
r2t->data_count = conn->max_xmit_dlength;
hdr->flags = 0;
} else {
hton24(hdr->dlength, r2t->data_length);
r2t->data_count = r2t->data_length;
hdr->flags = ISCSI_FLAG_CMD_FINAL;
}
conn->dataout_pdus_cnt++;
r2t->sent = 0;
}
/**
* iscsi_r2t_rsp - iSCSI R2T Response processing
* @conn: iscsi connection
* @task: scsi command task
**/
static int
iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
{
struct iscsi_r2t_info *r2t;
struct iscsi_session *session = conn->session;
struct iscsi_tcp_task *tcp_task = task->dd_data;
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
int r2tsn = be32_to_cpu(rhdr->r2tsn);
int rc;
if (tcp_conn->in.datalen) {
iscsi_conn_printk(KERN_ERR, conn,
"invalid R2t with datalen %d\n",
tcp_conn->in.datalen);
return ISCSI_ERR_DATALEN;
}
if (tcp_task->exp_datasn != r2tsn){
debug_tcp("%s: task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
__func__, tcp_task->exp_datasn, r2tsn);
return ISCSI_ERR_R2TSN;
}
/* fill-in new R2T associated with the task */
iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
iscsi_conn_printk(KERN_INFO, conn,
"dropping R2T itt %d in recovery.\n",
task->itt);
return 0;
}
rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
BUG_ON(!rc);
r2t->exp_statsn = rhdr->statsn;
r2t->data_length = be32_to_cpu(rhdr->data_length);
if (r2t->data_length == 0) {
iscsi_conn_printk(KERN_ERR, conn,
"invalid R2T with zero data len\n");
__kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
return ISCSI_ERR_DATALEN;
}
if (r2t->data_length > session->max_burst)
debug_scsi("invalid R2T with data len %u and max burst %u."
"Attempting to execute request.\n",
r2t->data_length, session->max_burst);
r2t->data_offset = be32_to_cpu(rhdr->data_offset);
if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
iscsi_conn_printk(KERN_ERR, conn,
"invalid R2T with data len %u at offset %u "
"and total length %d\n", r2t->data_length,
r2t->data_offset, scsi_out(task->sc)->length);
__kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
return ISCSI_ERR_DATALEN;
}
r2t->ttt = rhdr->ttt; /* no flip */
r2t->solicit_datasn = 0;
iscsi_solicit_data_init(conn, task, r2t);
tcp_task->exp_datasn = r2tsn + 1;
__kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
conn->r2t_pdus_cnt++;
iscsi_requeue_task(task);
return 0;
}
/*
* Handle incoming reply to DataIn command
*/
static int
iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
struct iscsi_segment *segment)
{
struct iscsi_conn *conn = tcp_conn->iscsi_conn;
struct iscsi_hdr *hdr = tcp_conn->in.hdr;
int rc;
if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
return ISCSI_ERR_DATA_DGST;
/* check for non-exceptional status */
if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
if (rc)
return rc;
}
iscsi_tcp_hdr_recv_prep(tcp_conn);
return 0;
}
/**
* iscsi_tcp_hdr_dissect - process PDU header
* @conn: iSCSI connection
* @hdr: PDU header
*
* This function analyzes the header of the PDU received,
* and performs several sanity checks. If the PDU is accompanied
* by data, the receive buffer is set up to copy the incoming data
* to the correct location.
*/
static int
iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
{
int rc = 0, opcode, ahslen;
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
struct iscsi_task *task;
/* verify PDU length */
tcp_conn->in.datalen = ntoh24(hdr->dlength);
if (tcp_conn->in.datalen > conn->max_recv_dlength) {
iscsi_conn_printk(KERN_ERR, conn,
"iscsi_tcp: datalen %d > %d\n",
tcp_conn->in.datalen, conn->max_recv_dlength);
return ISCSI_ERR_DATALEN;
}
/* Additional header segments. So far, we don't
* process additional headers.
*/
ahslen = hdr->hlength << 2;
opcode = hdr->opcode & ISCSI_OPCODE_MASK;
/* verify itt (itt encoding: age+cid+itt) */
rc = iscsi_verify_itt(conn, hdr->itt);
if (rc)
return rc;
debug_tcp("opcode 0x%x ahslen %d datalen %d\n",
opcode, ahslen, tcp_conn->in.datalen);
switch(opcode) {
case ISCSI_OP_SCSI_DATA_IN:
spin_lock(&conn->session->lock);
task = iscsi_itt_to_ctask(conn, hdr->itt);
if (!task)
rc = ISCSI_ERR_BAD_ITT;
else
rc = iscsi_data_in(conn, task);
if (rc) {
spin_unlock(&conn->session->lock);
break;
}
if (tcp_conn->in.datalen) {
struct iscsi_tcp_task *tcp_task = task->dd_data;
struct hash_desc *rx_hash = NULL;
struct scsi_data_buffer *sdb = scsi_in(task->sc);
/*
* Setup copy of Data-In into the Scsi_Cmnd
* Scatterlist case:
* We set up the iscsi_segment to point to the next
* scatterlist entry to copy to. As we go along,
* we move on to the next scatterlist entry and
* update the digest per-entry.
*/
if (conn->datadgst_en)
rx_hash = &tcp_conn->rx_hash;
debug_tcp("iscsi_tcp_begin_data_in(%p, offset=%d, "
"datalen=%d)\n", tcp_conn,
tcp_task->data_offset,
tcp_conn->in.datalen);
rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
sdb->table.sgl,
sdb->table.nents,
tcp_task->data_offset,
tcp_conn->in.datalen,
iscsi_tcp_process_data_in,
rx_hash);
spin_unlock(&conn->session->lock);
return rc;
}
rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
spin_unlock(&conn->session->lock);
break;
case ISCSI_OP_SCSI_CMD_RSP:
if (tcp_conn->in.datalen) {
iscsi_tcp_data_recv_prep(tcp_conn);
return 0;
}
rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
break;
case ISCSI_OP_R2T:
spin_lock(&conn->session->lock);
task = iscsi_itt_to_ctask(conn, hdr->itt);
if (!task)
rc = ISCSI_ERR_BAD_ITT;
else if (ahslen)
rc = ISCSI_ERR_AHSLEN;
else if (task->sc->sc_data_direction == DMA_TO_DEVICE)
rc = iscsi_r2t_rsp(conn, task);
else
rc = ISCSI_ERR_PROTO;
spin_unlock(&conn->session->lock);
break;
case ISCSI_OP_LOGIN_RSP:
case ISCSI_OP_TEXT_RSP:
case ISCSI_OP_REJECT:
case ISCSI_OP_ASYNC_EVENT:
/*
* It is possible that we could get a PDU with a buffer larger
* than 8K, but there are no targets that currently do this.
* For now we fail until we find a vendor that needs it
*/
if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
iscsi_conn_printk(KERN_ERR, conn,
"iscsi_tcp: received buffer of "
"len %u but conn buffer is only %u "
"(opcode %0x)\n",
tcp_conn->in.datalen,
ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
rc = ISCSI_ERR_PROTO;
break;
}
/* If there's data coming in with the response,
* receive it to the connection's buffer.
*/
if (tcp_conn->in.datalen) {
iscsi_tcp_data_recv_prep(tcp_conn);
return 0;
}
/* fall through */
case ISCSI_OP_LOGOUT_RSP:
case ISCSI_OP_NOOP_IN:
case ISCSI_OP_SCSI_TMFUNC_RSP:
rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
break;
default:
rc = ISCSI_ERR_BAD_OPCODE;
break;
}
if (rc == 0) {
/* Anything that comes with data should have
* been handled above. */
if (tcp_conn->in.datalen)
return ISCSI_ERR_PROTO;
iscsi_tcp_hdr_recv_prep(tcp_conn);
}
return rc;
}
/**
* iscsi_tcp_hdr_recv_done - process PDU header
*
* This is the callback invoked when the PDU header has
* been received. If the header is followed by additional
* header segments, we go back for more data.
*/
static int
iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
struct iscsi_segment *segment)
{
struct iscsi_conn *conn = tcp_conn->iscsi_conn;
struct iscsi_hdr *hdr;
/* Check if there are additional header segments
* *prior* to computing the digest, because we
* may need to go back to the caller for more.
*/
hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
/* Bump the header length - the caller will
* just loop around and get the AHS for us, and
* call again. */
unsigned int ahslen = hdr->hlength << 2;
/* Make sure we don't overflow */
if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
return ISCSI_ERR_AHSLEN;
segment->total_size += ahslen;
segment->size += ahslen;
return 0;
}
/* We're done processing the header. See if we're doing
* header digests; if so, set up the recv_digest buffer
* and go back for more. */
if (conn->hdrdgst_en) {
if (segment->digest_len == 0) {
iscsi_tcp_segment_splice_digest(segment,
segment->recv_digest);
return 0;
}
iscsi_tcp_dgst_header(&tcp_conn->rx_hash, hdr,
segment->total_copied - ISCSI_DIGEST_SIZE,
segment->digest);
if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
return ISCSI_ERR_HDR_DGST;
}
tcp_conn->in.hdr = hdr;
return iscsi_tcp_hdr_dissect(conn, hdr);
}
/**
* iscsi_tcp_recv - TCP receive in sendfile fashion
* @rd_desc: read descriptor
* @skb: socket buffer
* @offset: offset in skb
* @len: skb->len - offset
**/
static int
iscsi_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
unsigned int offset, size_t len)
{
struct iscsi_conn *conn = rd_desc->arg.data;
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
struct iscsi_segment *segment = &tcp_conn->in.segment;
struct skb_seq_state seq;
unsigned int consumed = 0;
int rc = 0;
debug_tcp("in %d bytes\n", skb->len - offset);
if (unlikely(conn->suspend_rx)) {
debug_tcp("conn %d Rx suspended!\n", conn->id);
return 0;
}
skb_prepare_seq_read(skb, offset, skb->len, &seq);
while (1) {
unsigned int avail;
const u8 *ptr;
avail = skb_seq_read(consumed, &ptr, &seq);
if (avail == 0) {
debug_tcp("no more data avail. Consumed %d\n",
consumed);
break;
}
BUG_ON(segment->copied >= segment->size);
debug_tcp("skb %p ptr=%p avail=%u\n", skb, ptr, avail);
rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
BUG_ON(rc == 0);
consumed += rc;
if (segment->total_copied >= segment->total_size) {
debug_tcp("segment done\n");
rc = segment->done(tcp_conn, segment);
if (rc != 0) {
skb_abort_seq_read(&seq);
goto error;
}
/* The done() functions sets up the
* next segment. */
}
}
skb_abort_seq_read(&seq);
conn->rxdata_octets += consumed;
return consumed;
error:
debug_tcp("Error receiving PDU, errno=%d\n", rc);
iscsi_conn_failure(conn, rc);
return 0;
}
static void
iscsi_tcp_data_ready(struct sock *sk, int flag)
{
struct iscsi_conn *conn = sk->sk_user_data;
struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
read_descriptor_t rd_desc;
read_lock(&sk->sk_callback_lock);
/*
* Use rd_desc to pass 'conn' to iscsi_tcp_recv.
* We set count to 1 because we want the network layer to
* hand us all the skbs that are available. iscsi_tcp_recv
* handled pdus that cross buffers or pdus that still need data.
*/