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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * iSCSI over TCP/IP Data-Path lib
4 *
5 * Copyright (C) 2004 Dmitry Yusupov
6 * Copyright (C) 2004 Alex Aizman
7 * Copyright (C) 2005 - 2006 Mike Christie
8 * Copyright (C) 2006 Red Hat, Inc. All rights reserved.
9 * maintained by open-iscsi@googlegroups.com
10 *
11 * Credits:
12 * Christoph Hellwig
13 * FUJITA Tomonori
14 * Arne Redlich
15 * Zhenyu Wang
16 */
17
18#include <crypto/hash.h>
19#include <linux/types.h>
20#include <linux/list.h>
21#include <linux/inet.h>
22#include <linux/slab.h>
23#include <linux/file.h>
24#include <linux/blkdev.h>
25#include <linux/delay.h>
26#include <linux/kfifo.h>
27#include <linux/scatterlist.h>
28#include <linux/module.h>
29#include <net/tcp.h>
30#include <scsi/scsi_cmnd.h>
31#include <scsi/scsi_device.h>
32#include <scsi/scsi_host.h>
33#include <scsi/scsi.h>
34#include <scsi/scsi_transport_iscsi.h>
35#include <trace/events/iscsi.h>
36
37#include "iscsi_tcp.h"
38
39MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
40 "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
41 "Alex Aizman <itn780@yahoo.com>");
42MODULE_DESCRIPTION("iSCSI/TCP data-path");
43MODULE_LICENSE("GPL");
44
45static int iscsi_dbg_libtcp;
46module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
47 S_IRUGO | S_IWUSR);
48MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
49 "module. Set to 1 to turn on, and zero to turn off. Default "
50 "is off.");
51
52#define ISCSI_DBG_TCP(_conn, dbg_fmt, arg...) \
53 do { \
54 if (iscsi_dbg_libtcp) \
55 iscsi_conn_printk(KERN_INFO, _conn, \
56 "%s " dbg_fmt, \
57 __func__, ##arg); \
58 iscsi_dbg_trace(trace_iscsi_dbg_tcp, \
59 &(_conn)->cls_conn->dev, \
60 "%s " dbg_fmt, __func__, ##arg);\
61 } while (0);
62
63static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
64 struct iscsi_segment *segment);
65
66/*
67 * Scatterlist handling: inside the iscsi_segment, we
68 * remember an index into the scatterlist, and set data/size
69 * to the current scatterlist entry. For highmem pages, we
70 * kmap as needed.
71 *
72 * Note that the page is unmapped when we return from
73 * TCP's data_ready handler, so we may end up mapping and
74 * unmapping the same page repeatedly. The whole reason
75 * for this is that we shouldn't keep the page mapped
76 * outside the softirq.
77 */
78
79/**
80 * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
81 * @segment: the buffer object
82 * @sg: scatterlist
83 * @offset: byte offset into that sg entry
84 *
85 * This function sets up the segment so that subsequent
86 * data is copied to the indicated sg entry, at the given
87 * offset.
88 */
89static inline void
90iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
91 struct scatterlist *sg, unsigned int offset)
92{
93 segment->sg = sg;
94 segment->sg_offset = offset;
95 segment->size = min(sg->length - offset,
96 segment->total_size - segment->total_copied);
97 segment->data = NULL;
98}
99
100/**
101 * iscsi_tcp_segment_map - map the current S/G page
102 * @segment: iscsi_segment
103 * @recv: 1 if called from recv path
104 *
105 * We only need to possibly kmap data if scatter lists are being used,
106 * because the iscsi passthrough and internal IO paths will never use high
107 * mem pages.
108 */
109static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
110{
111 struct scatterlist *sg;
112
113 if (segment->data != NULL || !segment->sg)
114 return;
115
116 sg = segment->sg;
117 BUG_ON(segment->sg_mapped);
118 BUG_ON(sg->length == 0);
119
120 /*
121 * We always map for the recv path.
122 *
123 * If the page count is greater than one it is ok to send
124 * to the network layer's zero copy send path. If not we
125 * have to go the slow sendmsg path.
126 *
127 * Same goes for slab pages: skb_can_coalesce() allows
128 * coalescing neighboring slab objects into a single frag which
129 * triggers one of hardened usercopy checks.
130 */
131 if (!recv && sendpage_ok(sg_page(sg)))
132 return;
133
134 if (recv) {
135 segment->atomic_mapped = true;
136 segment->sg_mapped = kmap_atomic(sg_page(sg));
137 } else {
138 segment->atomic_mapped = false;
139 /* the xmit path can sleep with the page mapped so use kmap */
140 segment->sg_mapped = kmap(sg_page(sg));
141 }
142
143 segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
144}
145
146void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
147{
148 if (segment->sg_mapped) {
149 if (segment->atomic_mapped)
150 kunmap_atomic(segment->sg_mapped);
151 else
152 kunmap(sg_page(segment->sg));
153 segment->sg_mapped = NULL;
154 segment->data = NULL;
155 }
156}
157EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
158
159/*
160 * Splice the digest buffer into the buffer
161 */
162static inline void
163iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
164{
165 segment->data = digest;
166 segment->digest_len = ISCSI_DIGEST_SIZE;
167 segment->total_size += ISCSI_DIGEST_SIZE;
168 segment->size = ISCSI_DIGEST_SIZE;
169 segment->copied = 0;
170 segment->sg = NULL;
171 segment->hash = NULL;
172}
173
174/**
175 * iscsi_tcp_segment_done - check whether the segment is complete
176 * @tcp_conn: iscsi tcp connection
177 * @segment: iscsi segment to check
178 * @recv: set to one of this is called from the recv path
179 * @copied: number of bytes copied
180 *
181 * Check if we're done receiving this segment. If the receive
182 * buffer is full but we expect more data, move on to the
183 * next entry in the scatterlist.
184 *
185 * If the amount of data we received isn't a multiple of 4,
186 * we will transparently receive the pad bytes, too.
187 *
188 * This function must be re-entrant.
189 */
190int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
191 struct iscsi_segment *segment, int recv,
192 unsigned copied)
193{
194 struct scatterlist sg;
195 unsigned int pad;
196
197 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
198 segment->copied, copied, segment->size,
199 recv ? "recv" : "xmit");
200 if (segment->hash && copied) {
201 /*
202 * If a segment is kmapd we must unmap it before sending
203 * to the crypto layer since that will try to kmap it again.
204 */
205 iscsi_tcp_segment_unmap(segment);
206
207 if (!segment->data) {
208 sg_init_table(&sg, 1);
209 sg_set_page(&sg, sg_page(segment->sg), copied,
210 segment->copied + segment->sg_offset +
211 segment->sg->offset);
212 } else
213 sg_init_one(&sg, segment->data + segment->copied,
214 copied);
215 ahash_request_set_crypt(segment->hash, &sg, NULL, copied);
216 crypto_ahash_update(segment->hash);
217 }
218
219 segment->copied += copied;
220 if (segment->copied < segment->size) {
221 iscsi_tcp_segment_map(segment, recv);
222 return 0;
223 }
224
225 segment->total_copied += segment->copied;
226 segment->copied = 0;
227 segment->size = 0;
228
229 /* Unmap the current scatterlist page, if there is one. */
230 iscsi_tcp_segment_unmap(segment);
231
232 /* Do we have more scatterlist entries? */
233 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
234 segment->total_copied, segment->total_size);
235 if (segment->total_copied < segment->total_size) {
236 /* Proceed to the next entry in the scatterlist. */
237 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
238 0);
239 iscsi_tcp_segment_map(segment, recv);
240 BUG_ON(segment->size == 0);
241 return 0;
242 }
243
244 /* Do we need to handle padding? */
245 if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
246 pad = iscsi_padding(segment->total_copied);
247 if (pad != 0) {
248 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
249 "consume %d pad bytes\n", pad);
250 segment->total_size += pad;
251 segment->size = pad;
252 segment->data = segment->padbuf;
253 return 0;
254 }
255 }
256
257 /*
258 * Set us up for transferring the data digest. hdr digest
259 * is completely handled in hdr done function.
260 */
261 if (segment->hash) {
262 ahash_request_set_crypt(segment->hash, NULL,
263 segment->digest, 0);
264 crypto_ahash_final(segment->hash);
265 iscsi_tcp_segment_splice_digest(segment,
266 recv ? segment->recv_digest : segment->digest);
267 return 0;
268 }
269
270 return 1;
271}
272EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
273
274/**
275 * iscsi_tcp_segment_recv - copy data to segment
276 * @tcp_conn: the iSCSI TCP connection
277 * @segment: the buffer to copy to
278 * @ptr: data pointer
279 * @len: amount of data available
280 *
281 * This function copies up to @len bytes to the
282 * given buffer, and returns the number of bytes
283 * consumed, which can actually be less than @len.
284 *
285 * If hash digest is enabled, the function will update the
286 * hash while copying.
287 * Combining these two operations doesn't buy us a lot (yet),
288 * but in the future we could implement combined copy+crc,
289 * just way we do for network layer checksums.
290 */
291static int
292iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
293 struct iscsi_segment *segment, const void *ptr,
294 unsigned int len)
295{
296 unsigned int copy = 0, copied = 0;
297
298 while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
299 if (copied == len) {
300 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
301 "copied %d bytes\n", len);
302 break;
303 }
304
305 copy = min(len - copied, segment->size - segment->copied);
306 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
307 memcpy(segment->data + segment->copied, ptr + copied, copy);
308 copied += copy;
309 }
310 return copied;
311}
312
313inline void
314iscsi_tcp_dgst_header(struct ahash_request *hash, const void *hdr,
315 size_t hdrlen, unsigned char digest[ISCSI_DIGEST_SIZE])
316{
317 struct scatterlist sg;
318
319 sg_init_one(&sg, hdr, hdrlen);
320 ahash_request_set_crypt(hash, &sg, digest, hdrlen);
321 crypto_ahash_digest(hash);
322}
323EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
324
325static inline int
326iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
327 struct iscsi_segment *segment)
328{
329 if (!segment->digest_len)
330 return 1;
331
332 if (memcmp(segment->recv_digest, segment->digest,
333 segment->digest_len)) {
334 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
335 return 0;
336 }
337
338 return 1;
339}
340
341/*
342 * Helper function to set up segment buffer
343 */
344static inline void
345__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
346 iscsi_segment_done_fn_t *done, struct ahash_request *hash)
347{
348 memset(segment, 0, sizeof(*segment));
349 segment->total_size = size;
350 segment->done = done;
351
352 if (hash) {
353 segment->hash = hash;
354 crypto_ahash_init(hash);
355 }
356}
357
358inline void
359iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
360 size_t size, iscsi_segment_done_fn_t *done,
361 struct ahash_request *hash)
362{
363 __iscsi_segment_init(segment, size, done, hash);
364 segment->data = data;
365 segment->size = size;
366}
367EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
368
369inline int
370iscsi_segment_seek_sg(struct iscsi_segment *segment,
371 struct scatterlist *sg_list, unsigned int sg_count,
372 unsigned int offset, size_t size,
373 iscsi_segment_done_fn_t *done,
374 struct ahash_request *hash)
375{
376 struct scatterlist *sg;
377 unsigned int i;
378
379 __iscsi_segment_init(segment, size, done, hash);
380 for_each_sg(sg_list, sg, sg_count, i) {
381 if (offset < sg->length) {
382 iscsi_tcp_segment_init_sg(segment, sg, offset);
383 return 0;
384 }
385 offset -= sg->length;
386 }
387
388 return ISCSI_ERR_DATA_OFFSET;
389}
390EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
391
392/**
393 * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
394 * @tcp_conn: iscsi connection to prep for
395 *
396 * This function always passes NULL for the hash argument, because when this
397 * function is called we do not yet know the final size of the header and want
398 * to delay the digest processing until we know that.
399 */
400void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
401{
402 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
403 "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
404 "digest enabled" : "digest disabled");
405 iscsi_segment_init_linear(&tcp_conn->in.segment,
406 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
407 iscsi_tcp_hdr_recv_done, NULL);
408}
409EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
410
411/*
412 * Handle incoming reply to any other type of command
413 */
414static int
415iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
416 struct iscsi_segment *segment)
417{
418 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
419 int rc = 0;
420
421 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
422 return ISCSI_ERR_DATA_DGST;
423
424 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
425 conn->data, tcp_conn->in.datalen);
426 if (rc)
427 return rc;
428
429 iscsi_tcp_hdr_recv_prep(tcp_conn);
430 return 0;
431}
432
433static void
434iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
435{
436 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
437 struct ahash_request *rx_hash = NULL;
438
439 if (conn->datadgst_en &&
440 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
441 rx_hash = tcp_conn->rx_hash;
442
443 iscsi_segment_init_linear(&tcp_conn->in.segment,
444 conn->data, tcp_conn->in.datalen,
445 iscsi_tcp_data_recv_done, rx_hash);
446}
447
448/**
449 * iscsi_tcp_cleanup_task - free tcp_task resources
450 * @task: iscsi task
451 *
452 * must be called with session back_lock
453 */
454void iscsi_tcp_cleanup_task(struct iscsi_task *task)
455{
456 struct iscsi_tcp_task *tcp_task = task->dd_data;
457 struct iscsi_r2t_info *r2t;
458
459 /* nothing to do for mgmt */
460 if (!task->sc)
461 return;
462
463 spin_lock_bh(&tcp_task->queue2pool);
464 /* flush task's r2t queues */
465 while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
466 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
467 sizeof(void*));
468 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
469 }
470
471 r2t = tcp_task->r2t;
472 if (r2t != NULL) {
473 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
474 sizeof(void*));
475 tcp_task->r2t = NULL;
476 }
477 spin_unlock_bh(&tcp_task->queue2pool);
478}
479EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
480
481/**
482 * iscsi_tcp_data_in - SCSI Data-In Response processing
483 * @conn: iscsi connection
484 * @task: scsi command task
485 */
486static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
487{
488 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
489 struct iscsi_tcp_task *tcp_task = task->dd_data;
490 struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
491 int datasn = be32_to_cpu(rhdr->datasn);
492 unsigned total_in_length = task->sc->sdb.length;
493
494 /*
495 * lib iscsi will update this in the completion handling if there
496 * is status.
497 */
498 if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
499 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
500
501 if (tcp_conn->in.datalen == 0)
502 return 0;
503
504 if (tcp_task->exp_datasn != datasn) {
505 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
506 "\n", tcp_task->exp_datasn, datasn);
507 return ISCSI_ERR_DATASN;
508 }
509
510 tcp_task->exp_datasn++;
511
512 tcp_task->data_offset = be32_to_cpu(rhdr->offset);
513 if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
514 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
515 "total_length_in(%d)\n", tcp_task->data_offset,
516 tcp_conn->in.datalen, total_in_length);
517 return ISCSI_ERR_DATA_OFFSET;
518 }
519
520 conn->datain_pdus_cnt++;
521 return 0;
522}
523
524/**
525 * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
526 * @conn: iscsi connection
527 * @hdr: PDU header
528 */
529static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
530{
531 struct iscsi_session *session = conn->session;
532 struct iscsi_tcp_task *tcp_task;
533 struct iscsi_tcp_conn *tcp_conn;
534 struct iscsi_r2t_rsp *rhdr;
535 struct iscsi_r2t_info *r2t;
536 struct iscsi_task *task;
537 u32 data_length;
538 u32 data_offset;
539 int r2tsn;
540 int rc;
541
542 spin_lock(&session->back_lock);
543 task = iscsi_itt_to_ctask(conn, hdr->itt);
544 if (!task) {
545 spin_unlock(&session->back_lock);
546 return ISCSI_ERR_BAD_ITT;
547 } else if (task->sc->sc_data_direction != DMA_TO_DEVICE) {
548 spin_unlock(&session->back_lock);
549 return ISCSI_ERR_PROTO;
550 }
551 /*
552 * A bad target might complete the cmd before we have handled R2Ts
553 * so get a ref to the task that will be dropped in the xmit path.
554 */
555 if (task->state != ISCSI_TASK_RUNNING) {
556 spin_unlock(&session->back_lock);
557 /* Let the path that got the early rsp complete it */
558 return 0;
559 }
560 task->last_xfer = jiffies;
561 if (!iscsi_get_task(task)) {
562 spin_unlock(&session->back_lock);
563 /* Let the path that got the early rsp complete it */
564 return 0;
565 }
566
567 tcp_conn = conn->dd_data;
568 rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
569 /* fill-in new R2T associated with the task */
570 iscsi_update_cmdsn(session, (struct iscsi_nopin *)rhdr);
571 spin_unlock(&session->back_lock);
572
573 if (tcp_conn->in.datalen) {
574 iscsi_conn_printk(KERN_ERR, conn,
575 "invalid R2t with datalen %d\n",
576 tcp_conn->in.datalen);
577 rc = ISCSI_ERR_DATALEN;
578 goto put_task;
579 }
580
581 tcp_task = task->dd_data;
582 r2tsn = be32_to_cpu(rhdr->r2tsn);
583 if (tcp_task->exp_datasn != r2tsn){
584 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
585 tcp_task->exp_datasn, r2tsn);
586 rc = ISCSI_ERR_R2TSN;
587 goto put_task;
588 }
589
590 if (session->state != ISCSI_STATE_LOGGED_IN) {
591 iscsi_conn_printk(KERN_INFO, conn,
592 "dropping R2T itt %d in recovery.\n",
593 task->itt);
594 rc = 0;
595 goto put_task;
596 }
597
598 data_length = be32_to_cpu(rhdr->data_length);
599 if (data_length == 0) {
600 iscsi_conn_printk(KERN_ERR, conn,
601 "invalid R2T with zero data len\n");
602 rc = ISCSI_ERR_DATALEN;
603 goto put_task;
604 }
605
606 if (data_length > session->max_burst)
607 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
608 "burst %u. Attempting to execute request.\n",
609 data_length, session->max_burst);
610
611 data_offset = be32_to_cpu(rhdr->data_offset);
612 if (data_offset + data_length > task->sc->sdb.length) {
613 iscsi_conn_printk(KERN_ERR, conn,
614 "invalid R2T with data len %u at offset %u "
615 "and total length %d\n", data_length,
616 data_offset, task->sc->sdb.length);
617 rc = ISCSI_ERR_DATALEN;
618 goto put_task;
619 }
620
621 spin_lock(&tcp_task->pool2queue);
622 rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
623 if (!rc) {
624 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
625 "Target has sent more R2Ts than it "
626 "negotiated for or driver has leaked.\n");
627 spin_unlock(&tcp_task->pool2queue);
628 rc = ISCSI_ERR_PROTO;
629 goto put_task;
630 }
631
632 r2t->exp_statsn = rhdr->statsn;
633 r2t->data_length = data_length;
634 r2t->data_offset = data_offset;
635
636 r2t->ttt = rhdr->ttt; /* no flip */
637 r2t->datasn = 0;
638 r2t->sent = 0;
639
640 tcp_task->exp_datasn = r2tsn + 1;
641 kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
642 conn->r2t_pdus_cnt++;
643 spin_unlock(&tcp_task->pool2queue);
644
645 iscsi_requeue_task(task);
646 return 0;
647
648put_task:
649 iscsi_put_task(task);
650 return rc;
651}
652
653/*
654 * Handle incoming reply to DataIn command
655 */
656static int
657iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
658 struct iscsi_segment *segment)
659{
660 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
661 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
662 int rc;
663
664 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
665 return ISCSI_ERR_DATA_DGST;
666
667 /* check for non-exceptional status */
668 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
669 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
670 if (rc)
671 return rc;
672 }
673
674 iscsi_tcp_hdr_recv_prep(tcp_conn);
675 return 0;
676}
677
678/**
679 * iscsi_tcp_hdr_dissect - process PDU header
680 * @conn: iSCSI connection
681 * @hdr: PDU header
682 *
683 * This function analyzes the header of the PDU received,
684 * and performs several sanity checks. If the PDU is accompanied
685 * by data, the receive buffer is set up to copy the incoming data
686 * to the correct location.
687 */
688static int
689iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
690{
691 int rc = 0, opcode, ahslen;
692 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
693 struct iscsi_task *task;
694
695 /* verify PDU length */
696 tcp_conn->in.datalen = ntoh24(hdr->dlength);
697 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
698 iscsi_conn_printk(KERN_ERR, conn,
699 "iscsi_tcp: datalen %d > %d\n",
700 tcp_conn->in.datalen, conn->max_recv_dlength);
701 return ISCSI_ERR_DATALEN;
702 }
703
704 /* Additional header segments. So far, we don't
705 * process additional headers.
706 */
707 ahslen = hdr->hlength << 2;
708
709 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
710 /* verify itt (itt encoding: age+cid+itt) */
711 rc = iscsi_verify_itt(conn, hdr->itt);
712 if (rc)
713 return rc;
714
715 ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
716 opcode, ahslen, tcp_conn->in.datalen);
717
718 switch(opcode) {
719 case ISCSI_OP_SCSI_DATA_IN:
720 spin_lock(&conn->session->back_lock);
721 task = iscsi_itt_to_ctask(conn, hdr->itt);
722 if (!task)
723 rc = ISCSI_ERR_BAD_ITT;
724 else
725 rc = iscsi_tcp_data_in(conn, task);
726 if (rc) {
727 spin_unlock(&conn->session->back_lock);
728 break;
729 }
730
731 if (tcp_conn->in.datalen) {
732 struct iscsi_tcp_task *tcp_task = task->dd_data;
733 struct ahash_request *rx_hash = NULL;
734 struct scsi_data_buffer *sdb = &task->sc->sdb;
735
736 /*
737 * Setup copy of Data-In into the struct scsi_cmnd
738 * Scatterlist case:
739 * We set up the iscsi_segment to point to the next
740 * scatterlist entry to copy to. As we go along,
741 * we move on to the next scatterlist entry and
742 * update the digest per-entry.
743 */
744 if (conn->datadgst_en &&
745 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
746 rx_hash = tcp_conn->rx_hash;
747
748 ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
749 "offset=%d, datalen=%d)\n",
750 tcp_task->data_offset,
751 tcp_conn->in.datalen);
752 task->last_xfer = jiffies;
753 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
754 sdb->table.sgl,
755 sdb->table.nents,
756 tcp_task->data_offset,
757 tcp_conn->in.datalen,
758 iscsi_tcp_process_data_in,
759 rx_hash);
760 spin_unlock(&conn->session->back_lock);
761 return rc;
762 }
763 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
764 spin_unlock(&conn->session->back_lock);
765 break;
766 case ISCSI_OP_SCSI_CMD_RSP:
767 if (tcp_conn->in.datalen) {
768 iscsi_tcp_data_recv_prep(tcp_conn);
769 return 0;
770 }
771 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
772 break;
773 case ISCSI_OP_R2T:
774 if (ahslen) {
775 rc = ISCSI_ERR_AHSLEN;
776 break;
777 }
778 rc = iscsi_tcp_r2t_rsp(conn, hdr);
779 break;
780 case ISCSI_OP_LOGIN_RSP:
781 case ISCSI_OP_TEXT_RSP:
782 case ISCSI_OP_REJECT:
783 case ISCSI_OP_ASYNC_EVENT:
784 /*
785 * It is possible that we could get a PDU with a buffer larger
786 * than 8K, but there are no targets that currently do this.
787 * For now we fail until we find a vendor that needs it
788 */
789 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
790 iscsi_conn_printk(KERN_ERR, conn,
791 "iscsi_tcp: received buffer of "
792 "len %u but conn buffer is only %u "
793 "(opcode %0x)\n",
794 tcp_conn->in.datalen,
795 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
796 rc = ISCSI_ERR_PROTO;
797 break;
798 }
799
800 /* If there's data coming in with the response,
801 * receive it to the connection's buffer.
802 */
803 if (tcp_conn->in.datalen) {
804 iscsi_tcp_data_recv_prep(tcp_conn);
805 return 0;
806 }
807 fallthrough;
808 case ISCSI_OP_LOGOUT_RSP:
809 case ISCSI_OP_NOOP_IN:
810 case ISCSI_OP_SCSI_TMFUNC_RSP:
811 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
812 break;
813 default:
814 rc = ISCSI_ERR_BAD_OPCODE;
815 break;
816 }
817
818 if (rc == 0) {
819 /* Anything that comes with data should have
820 * been handled above. */
821 if (tcp_conn->in.datalen)
822 return ISCSI_ERR_PROTO;
823 iscsi_tcp_hdr_recv_prep(tcp_conn);
824 }
825
826 return rc;
827}
828
829/**
830 * iscsi_tcp_hdr_recv_done - process PDU header
831 * @tcp_conn: iSCSI TCP connection
832 * @segment: the buffer segment being processed
833 *
834 * This is the callback invoked when the PDU header has
835 * been received. If the header is followed by additional
836 * header segments, we go back for more data.
837 */
838static int
839iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
840 struct iscsi_segment *segment)
841{
842 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
843 struct iscsi_hdr *hdr;
844
845 /* Check if there are additional header segments
846 * *prior* to computing the digest, because we
847 * may need to go back to the caller for more.
848 */
849 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
850 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
851 /* Bump the header length - the caller will
852 * just loop around and get the AHS for us, and
853 * call again. */
854 unsigned int ahslen = hdr->hlength << 2;
855
856 /* Make sure we don't overflow */
857 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
858 return ISCSI_ERR_AHSLEN;
859
860 segment->total_size += ahslen;
861 segment->size += ahslen;
862 return 0;
863 }
864
865 /* We're done processing the header. See if we're doing
866 * header digests; if so, set up the recv_digest buffer
867 * and go back for more. */
868 if (conn->hdrdgst_en &&
869 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
870 if (segment->digest_len == 0) {
871 /*
872 * Even if we offload the digest processing we
873 * splice it in so we can increment the skb/segment
874 * counters in preparation for the data segment.
875 */
876 iscsi_tcp_segment_splice_digest(segment,
877 segment->recv_digest);
878 return 0;
879 }
880
881 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
882 segment->total_copied - ISCSI_DIGEST_SIZE,
883 segment->digest);
884
885 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
886 return ISCSI_ERR_HDR_DGST;
887 }
888
889 tcp_conn->in.hdr = hdr;
890 return iscsi_tcp_hdr_dissect(conn, hdr);
891}
892
893/**
894 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
895 * @tcp_conn: iscsi tcp conn
896 *
897 * returns non zero if we are currently processing or setup to process
898 * a header.
899 */
900inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
901{
902 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
903}
904EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
905
906/**
907 * iscsi_tcp_recv_skb - Process skb
908 * @conn: iscsi connection
909 * @skb: network buffer with header and/or data segment
910 * @offset: offset in skb
911 * @offloaded: bool indicating if transfer was offloaded
912 * @status: iscsi TCP status result
913 *
914 * Will return status of transfer in @status. And will return
915 * number of bytes copied.
916 */
917int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
918 unsigned int offset, bool offloaded, int *status)
919{
920 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
921 struct iscsi_segment *segment = &tcp_conn->in.segment;
922 struct skb_seq_state seq;
923 unsigned int consumed = 0;
924 int rc = 0;
925
926 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
927 /*
928 * Update for each skb instead of pdu, because over slow networks a
929 * data_in's data could take a while to read in. We also want to
930 * account for r2ts.
931 */
932 conn->last_recv = jiffies;
933
934 if (unlikely(test_bit(ISCSI_CONN_FLAG_SUSPEND_RX, &conn->flags))) {
935 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
936 *status = ISCSI_TCP_SUSPENDED;
937 return 0;
938 }
939
940 if (offloaded) {
941 segment->total_copied = segment->total_size;
942 goto segment_done;
943 }
944
945 skb_prepare_seq_read(skb, offset, skb->len, &seq);
946 while (1) {
947 unsigned int avail;
948 const u8 *ptr;
949
950 avail = skb_seq_read(consumed, &ptr, &seq);
951 if (avail == 0) {
952 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
953 consumed);
954 *status = ISCSI_TCP_SKB_DONE;
955 goto skb_done;
956 }
957 BUG_ON(segment->copied >= segment->size);
958
959 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
960 avail);
961 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
962 BUG_ON(rc == 0);
963 consumed += rc;
964
965 if (segment->total_copied >= segment->total_size) {
966 skb_abort_seq_read(&seq);
967 goto segment_done;
968 }
969 }
970
971segment_done:
972 *status = ISCSI_TCP_SEGMENT_DONE;
973 ISCSI_DBG_TCP(conn, "segment done\n");
974 rc = segment->done(tcp_conn, segment);
975 if (rc != 0) {
976 *status = ISCSI_TCP_CONN_ERR;
977 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
978 iscsi_conn_failure(conn, rc);
979 return 0;
980 }
981 /* The done() functions sets up the next segment. */
982
983skb_done:
984 conn->rxdata_octets += consumed;
985 return consumed;
986}
987EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
988
989/**
990 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
991 * @task: scsi command task
992 */
993int iscsi_tcp_task_init(struct iscsi_task *task)
994{
995 struct iscsi_tcp_task *tcp_task = task->dd_data;
996 struct iscsi_conn *conn = task->conn;
997 struct scsi_cmnd *sc = task->sc;
998 int err;
999
1000 if (!sc) {
1001 /*
1002 * mgmt tasks do not have a scatterlist since they come
1003 * in from the iscsi interface.
1004 */
1005 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
1006
1007 return conn->session->tt->init_pdu(task, 0, task->data_count);
1008 }
1009
1010 BUG_ON(kfifo_len(&tcp_task->r2tqueue));
1011 tcp_task->exp_datasn = 0;
1012
1013 /* Prepare PDU, optionally w/ immediate data */
1014 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
1015 task->itt, task->imm_count, task->unsol_r2t.data_length);
1016
1017 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
1018 if (err)
1019 return err;
1020 task->imm_count = 0;
1021 return 0;
1022}
1023EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
1024
1025static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
1026{
1027 struct iscsi_tcp_task *tcp_task = task->dd_data;
1028 struct iscsi_r2t_info *r2t = NULL;
1029
1030 if (iscsi_task_has_unsol_data(task))
1031 r2t = &task->unsol_r2t;
1032 else {
1033 spin_lock_bh(&tcp_task->queue2pool);
1034 if (tcp_task->r2t) {
1035 r2t = tcp_task->r2t;
1036 /* Continue with this R2T? */
1037 if (r2t->data_length <= r2t->sent) {
1038 ISCSI_DBG_TCP(task->conn,
1039 " done with r2t %p\n", r2t);
1040 kfifo_in(&tcp_task->r2tpool.queue,
1041 (void *)&tcp_task->r2t,
1042 sizeof(void *));
1043 tcp_task->r2t = r2t = NULL;
1044 }
1045 }
1046
1047 if (r2t == NULL) {
1048 if (kfifo_out(&tcp_task->r2tqueue,
1049 (void *)&tcp_task->r2t, sizeof(void *)) !=
1050 sizeof(void *))
1051 r2t = NULL;
1052 else
1053 r2t = tcp_task->r2t;
1054 }
1055 spin_unlock_bh(&tcp_task->queue2pool);
1056 }
1057
1058 return r2t;
1059}
1060
1061/**
1062 * iscsi_tcp_task_xmit - xmit normal PDU task
1063 * @task: iscsi command task
1064 *
1065 * We're expected to return 0 when everything was transmitted successfully,
1066 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1067 * of error.
1068 */
1069int iscsi_tcp_task_xmit(struct iscsi_task *task)
1070{
1071 struct iscsi_conn *conn = task->conn;
1072 struct iscsi_session *session = conn->session;
1073 struct iscsi_r2t_info *r2t;
1074 int rc = 0;
1075
1076flush:
1077 /* Flush any pending data first. */
1078 rc = session->tt->xmit_pdu(task);
1079 if (rc < 0)
1080 return rc;
1081
1082 /* mgmt command */
1083 if (!task->sc) {
1084 if (task->hdr->itt == RESERVED_ITT)
1085 iscsi_put_task(task);
1086 return 0;
1087 }
1088
1089 /* Are we done already? */
1090 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1091 return 0;
1092
1093 r2t = iscsi_tcp_get_curr_r2t(task);
1094 if (r2t == NULL) {
1095 /* Waiting for more R2Ts to arrive. */
1096 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1097 return 0;
1098 }
1099
1100 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1101 if (rc)
1102 return rc;
1103 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1104
1105 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1106 r2t, r2t->datasn - 1, task->hdr->itt,
1107 r2t->data_offset + r2t->sent, r2t->data_count);
1108
1109 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1110 r2t->data_count);
1111 if (rc) {
1112 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1113 return rc;
1114 }
1115
1116 r2t->sent += r2t->data_count;
1117 goto flush;
1118}
1119EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1120
1121struct iscsi_cls_conn *
1122iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1123 uint32_t conn_idx)
1124
1125{
1126 struct iscsi_conn *conn;
1127 struct iscsi_cls_conn *cls_conn;
1128 struct iscsi_tcp_conn *tcp_conn;
1129
1130 cls_conn = iscsi_conn_setup(cls_session,
1131 sizeof(*tcp_conn) + dd_data_size, conn_idx);
1132 if (!cls_conn)
1133 return NULL;
1134 conn = cls_conn->dd_data;
1135 /*
1136 * due to strange issues with iser these are not set
1137 * in iscsi_conn_setup
1138 */
1139 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1140
1141 tcp_conn = conn->dd_data;
1142 tcp_conn->iscsi_conn = conn;
1143 tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1144 return cls_conn;
1145}
1146EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1147
1148void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1149{
1150 iscsi_conn_teardown(cls_conn);
1151}
1152EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1153
1154int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1155{
1156 int i;
1157 int cmd_i;
1158
1159 /*
1160 * initialize per-task: R2T pool and xmit queue
1161 */
1162 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1163 struct iscsi_task *task = session->cmds[cmd_i];
1164 struct iscsi_tcp_task *tcp_task = task->dd_data;
1165
1166 /*
1167 * pre-allocated x2 as much r2ts to handle race when
1168 * target acks DataOut faster than we data_xmit() queues
1169 * could replenish r2tqueue.
1170 */
1171
1172 /* R2T pool */
1173 if (iscsi_pool_init(&tcp_task->r2tpool,
1174 session->max_r2t * 2, NULL,
1175 sizeof(struct iscsi_r2t_info))) {
1176 goto r2t_alloc_fail;
1177 }
1178
1179 /* R2T xmit queue */
1180 if (kfifo_alloc(&tcp_task->r2tqueue,
1181 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1182 iscsi_pool_free(&tcp_task->r2tpool);
1183 goto r2t_alloc_fail;
1184 }
1185 spin_lock_init(&tcp_task->pool2queue);
1186 spin_lock_init(&tcp_task->queue2pool);
1187 }
1188
1189 return 0;
1190
1191r2t_alloc_fail:
1192 for (i = 0; i < cmd_i; i++) {
1193 struct iscsi_task *task = session->cmds[i];
1194 struct iscsi_tcp_task *tcp_task = task->dd_data;
1195
1196 kfifo_free(&tcp_task->r2tqueue);
1197 iscsi_pool_free(&tcp_task->r2tpool);
1198 }
1199 return -ENOMEM;
1200}
1201EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1202
1203void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1204{
1205 int i;
1206
1207 for (i = 0; i < session->cmds_max; i++) {
1208 struct iscsi_task *task = session->cmds[i];
1209 struct iscsi_tcp_task *tcp_task = task->dd_data;
1210
1211 kfifo_free(&tcp_task->r2tqueue);
1212 iscsi_pool_free(&tcp_task->r2tpool);
1213 }
1214}
1215EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1216
1217int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1218{
1219 struct iscsi_session *session = conn->session;
1220 unsigned short r2ts = 0;
1221
1222 sscanf(buf, "%hu", &r2ts);
1223 if (session->max_r2t == r2ts)
1224 return 0;
1225
1226 if (!r2ts || !is_power_of_2(r2ts))
1227 return -EINVAL;
1228
1229 session->max_r2t = r2ts;
1230 iscsi_tcp_r2tpool_free(session);
1231 return iscsi_tcp_r2tpool_alloc(session);
1232}
1233EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1234
1235void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1236 struct iscsi_stats *stats)
1237{
1238 struct iscsi_conn *conn = cls_conn->dd_data;
1239
1240 stats->txdata_octets = conn->txdata_octets;
1241 stats->rxdata_octets = conn->rxdata_octets;
1242 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1243 stats->dataout_pdus = conn->dataout_pdus_cnt;
1244 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1245 stats->datain_pdus = conn->datain_pdus_cnt;
1246 stats->r2t_pdus = conn->r2t_pdus_cnt;
1247 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1248 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1249}
1250EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);
1/*
2 * iSCSI over TCP/IP Data-Path lib
3 *
4 * Copyright (C) 2004 Dmitry Yusupov
5 * Copyright (C) 2004 Alex Aizman
6 * Copyright (C) 2005 - 2006 Mike Christie
7 * Copyright (C) 2006 Red Hat, Inc. All rights reserved.
8 * maintained by open-iscsi@googlegroups.com
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published
12 * by the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * See the file COPYING included with this distribution for more details.
21 *
22 * Credits:
23 * Christoph Hellwig
24 * FUJITA Tomonori
25 * Arne Redlich
26 * Zhenyu Wang
27 */
28
29#include <crypto/hash.h>
30#include <linux/types.h>
31#include <linux/list.h>
32#include <linux/inet.h>
33#include <linux/slab.h>
34#include <linux/file.h>
35#include <linux/blkdev.h>
36#include <linux/delay.h>
37#include <linux/kfifo.h>
38#include <linux/scatterlist.h>
39#include <linux/module.h>
40#include <net/tcp.h>
41#include <scsi/scsi_cmnd.h>
42#include <scsi/scsi_device.h>
43#include <scsi/scsi_host.h>
44#include <scsi/scsi.h>
45#include <scsi/scsi_transport_iscsi.h>
46
47#include "iscsi_tcp.h"
48
49MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
50 "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
51 "Alex Aizman <itn780@yahoo.com>");
52MODULE_DESCRIPTION("iSCSI/TCP data-path");
53MODULE_LICENSE("GPL");
54
55static int iscsi_dbg_libtcp;
56module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
57 S_IRUGO | S_IWUSR);
58MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
59 "module. Set to 1 to turn on, and zero to turn off. Default "
60 "is off.");
61
62#define ISCSI_DBG_TCP(_conn, dbg_fmt, arg...) \
63 do { \
64 if (iscsi_dbg_libtcp) \
65 iscsi_conn_printk(KERN_INFO, _conn, \
66 "%s " dbg_fmt, \
67 __func__, ##arg); \
68 } while (0);
69
70static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
71 struct iscsi_segment *segment);
72
73/*
74 * Scatterlist handling: inside the iscsi_segment, we
75 * remember an index into the scatterlist, and set data/size
76 * to the current scatterlist entry. For highmem pages, we
77 * kmap as needed.
78 *
79 * Note that the page is unmapped when we return from
80 * TCP's data_ready handler, so we may end up mapping and
81 * unmapping the same page repeatedly. The whole reason
82 * for this is that we shouldn't keep the page mapped
83 * outside the softirq.
84 */
85
86/**
87 * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
88 * @segment: the buffer object
89 * @sg: scatterlist
90 * @offset: byte offset into that sg entry
91 *
92 * This function sets up the segment so that subsequent
93 * data is copied to the indicated sg entry, at the given
94 * offset.
95 */
96static inline void
97iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
98 struct scatterlist *sg, unsigned int offset)
99{
100 segment->sg = sg;
101 segment->sg_offset = offset;
102 segment->size = min(sg->length - offset,
103 segment->total_size - segment->total_copied);
104 segment->data = NULL;
105}
106
107/**
108 * iscsi_tcp_segment_map - map the current S/G page
109 * @segment: iscsi_segment
110 * @recv: 1 if called from recv path
111 *
112 * We only need to possibly kmap data if scatter lists are being used,
113 * because the iscsi passthrough and internal IO paths will never use high
114 * mem pages.
115 */
116static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
117{
118 struct scatterlist *sg;
119
120 if (segment->data != NULL || !segment->sg)
121 return;
122
123 sg = segment->sg;
124 BUG_ON(segment->sg_mapped);
125 BUG_ON(sg->length == 0);
126
127 /*
128 * If the page count is greater than one it is ok to send
129 * to the network layer's zero copy send path. If not we
130 * have to go the slow sendmsg path. We always map for the
131 * recv path.
132 */
133 if (page_count(sg_page(sg)) >= 1 && !recv)
134 return;
135
136 if (recv) {
137 segment->atomic_mapped = true;
138 segment->sg_mapped = kmap_atomic(sg_page(sg));
139 } else {
140 segment->atomic_mapped = false;
141 /* the xmit path can sleep with the page mapped so use kmap */
142 segment->sg_mapped = kmap(sg_page(sg));
143 }
144
145 segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
146}
147
148void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
149{
150 if (segment->sg_mapped) {
151 if (segment->atomic_mapped)
152 kunmap_atomic(segment->sg_mapped);
153 else
154 kunmap(sg_page(segment->sg));
155 segment->sg_mapped = NULL;
156 segment->data = NULL;
157 }
158}
159EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
160
161/*
162 * Splice the digest buffer into the buffer
163 */
164static inline void
165iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
166{
167 segment->data = digest;
168 segment->digest_len = ISCSI_DIGEST_SIZE;
169 segment->total_size += ISCSI_DIGEST_SIZE;
170 segment->size = ISCSI_DIGEST_SIZE;
171 segment->copied = 0;
172 segment->sg = NULL;
173 segment->hash = NULL;
174}
175
176/**
177 * iscsi_tcp_segment_done - check whether the segment is complete
178 * @tcp_conn: iscsi tcp connection
179 * @segment: iscsi segment to check
180 * @recv: set to one of this is called from the recv path
181 * @copied: number of bytes copied
182 *
183 * Check if we're done receiving this segment. If the receive
184 * buffer is full but we expect more data, move on to the
185 * next entry in the scatterlist.
186 *
187 * If the amount of data we received isn't a multiple of 4,
188 * we will transparently receive the pad bytes, too.
189 *
190 * This function must be re-entrant.
191 */
192int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
193 struct iscsi_segment *segment, int recv,
194 unsigned copied)
195{
196 struct scatterlist sg;
197 unsigned int pad;
198
199 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
200 segment->copied, copied, segment->size,
201 recv ? "recv" : "xmit");
202 if (segment->hash && copied) {
203 /*
204 * If a segment is kmapd we must unmap it before sending
205 * to the crypto layer since that will try to kmap it again.
206 */
207 iscsi_tcp_segment_unmap(segment);
208
209 if (!segment->data) {
210 sg_init_table(&sg, 1);
211 sg_set_page(&sg, sg_page(segment->sg), copied,
212 segment->copied + segment->sg_offset +
213 segment->sg->offset);
214 } else
215 sg_init_one(&sg, segment->data + segment->copied,
216 copied);
217 ahash_request_set_crypt(segment->hash, &sg, NULL, copied);
218 crypto_ahash_update(segment->hash);
219 }
220
221 segment->copied += copied;
222 if (segment->copied < segment->size) {
223 iscsi_tcp_segment_map(segment, recv);
224 return 0;
225 }
226
227 segment->total_copied += segment->copied;
228 segment->copied = 0;
229 segment->size = 0;
230
231 /* Unmap the current scatterlist page, if there is one. */
232 iscsi_tcp_segment_unmap(segment);
233
234 /* Do we have more scatterlist entries? */
235 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
236 segment->total_copied, segment->total_size);
237 if (segment->total_copied < segment->total_size) {
238 /* Proceed to the next entry in the scatterlist. */
239 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
240 0);
241 iscsi_tcp_segment_map(segment, recv);
242 BUG_ON(segment->size == 0);
243 return 0;
244 }
245
246 /* Do we need to handle padding? */
247 if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
248 pad = iscsi_padding(segment->total_copied);
249 if (pad != 0) {
250 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
251 "consume %d pad bytes\n", pad);
252 segment->total_size += pad;
253 segment->size = pad;
254 segment->data = segment->padbuf;
255 return 0;
256 }
257 }
258
259 /*
260 * Set us up for transferring the data digest. hdr digest
261 * is completely handled in hdr done function.
262 */
263 if (segment->hash) {
264 ahash_request_set_crypt(segment->hash, NULL,
265 segment->digest, 0);
266 crypto_ahash_final(segment->hash);
267 iscsi_tcp_segment_splice_digest(segment,
268 recv ? segment->recv_digest : segment->digest);
269 return 0;
270 }
271
272 return 1;
273}
274EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
275
276/**
277 * iscsi_tcp_segment_recv - copy data to segment
278 * @tcp_conn: the iSCSI TCP connection
279 * @segment: the buffer to copy to
280 * @ptr: data pointer
281 * @len: amount of data available
282 *
283 * This function copies up to @len bytes to the
284 * given buffer, and returns the number of bytes
285 * consumed, which can actually be less than @len.
286 *
287 * If hash digest is enabled, the function will update the
288 * hash while copying.
289 * Combining these two operations doesn't buy us a lot (yet),
290 * but in the future we could implement combined copy+crc,
291 * just way we do for network layer checksums.
292 */
293static int
294iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
295 struct iscsi_segment *segment, const void *ptr,
296 unsigned int len)
297{
298 unsigned int copy = 0, copied = 0;
299
300 while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
301 if (copied == len) {
302 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
303 "copied %d bytes\n", len);
304 break;
305 }
306
307 copy = min(len - copied, segment->size - segment->copied);
308 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
309 memcpy(segment->data + segment->copied, ptr + copied, copy);
310 copied += copy;
311 }
312 return copied;
313}
314
315inline void
316iscsi_tcp_dgst_header(struct ahash_request *hash, const void *hdr,
317 size_t hdrlen, unsigned char digest[ISCSI_DIGEST_SIZE])
318{
319 struct scatterlist sg;
320
321 sg_init_one(&sg, hdr, hdrlen);
322 ahash_request_set_crypt(hash, &sg, digest, hdrlen);
323 crypto_ahash_digest(hash);
324}
325EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
326
327static inline int
328iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
329 struct iscsi_segment *segment)
330{
331 if (!segment->digest_len)
332 return 1;
333
334 if (memcmp(segment->recv_digest, segment->digest,
335 segment->digest_len)) {
336 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
337 return 0;
338 }
339
340 return 1;
341}
342
343/*
344 * Helper function to set up segment buffer
345 */
346static inline void
347__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
348 iscsi_segment_done_fn_t *done, struct ahash_request *hash)
349{
350 memset(segment, 0, sizeof(*segment));
351 segment->total_size = size;
352 segment->done = done;
353
354 if (hash) {
355 segment->hash = hash;
356 crypto_ahash_init(hash);
357 }
358}
359
360inline void
361iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
362 size_t size, iscsi_segment_done_fn_t *done,
363 struct ahash_request *hash)
364{
365 __iscsi_segment_init(segment, size, done, hash);
366 segment->data = data;
367 segment->size = size;
368}
369EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
370
371inline int
372iscsi_segment_seek_sg(struct iscsi_segment *segment,
373 struct scatterlist *sg_list, unsigned int sg_count,
374 unsigned int offset, size_t size,
375 iscsi_segment_done_fn_t *done,
376 struct ahash_request *hash)
377{
378 struct scatterlist *sg;
379 unsigned int i;
380
381 __iscsi_segment_init(segment, size, done, hash);
382 for_each_sg(sg_list, sg, sg_count, i) {
383 if (offset < sg->length) {
384 iscsi_tcp_segment_init_sg(segment, sg, offset);
385 return 0;
386 }
387 offset -= sg->length;
388 }
389
390 return ISCSI_ERR_DATA_OFFSET;
391}
392EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
393
394/**
395 * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
396 * @tcp_conn: iscsi connection to prep for
397 *
398 * This function always passes NULL for the hash argument, because when this
399 * function is called we do not yet know the final size of the header and want
400 * to delay the digest processing until we know that.
401 */
402void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
403{
404 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
405 "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
406 "digest enabled" : "digest disabled");
407 iscsi_segment_init_linear(&tcp_conn->in.segment,
408 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
409 iscsi_tcp_hdr_recv_done, NULL);
410}
411EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
412
413/*
414 * Handle incoming reply to any other type of command
415 */
416static int
417iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
418 struct iscsi_segment *segment)
419{
420 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
421 int rc = 0;
422
423 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
424 return ISCSI_ERR_DATA_DGST;
425
426 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
427 conn->data, tcp_conn->in.datalen);
428 if (rc)
429 return rc;
430
431 iscsi_tcp_hdr_recv_prep(tcp_conn);
432 return 0;
433}
434
435static void
436iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
437{
438 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
439 struct ahash_request *rx_hash = NULL;
440
441 if (conn->datadgst_en &&
442 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
443 rx_hash = tcp_conn->rx_hash;
444
445 iscsi_segment_init_linear(&tcp_conn->in.segment,
446 conn->data, tcp_conn->in.datalen,
447 iscsi_tcp_data_recv_done, rx_hash);
448}
449
450/**
451 * iscsi_tcp_cleanup_task - free tcp_task resources
452 * @task: iscsi task
453 *
454 * must be called with session back_lock
455 */
456void iscsi_tcp_cleanup_task(struct iscsi_task *task)
457{
458 struct iscsi_tcp_task *tcp_task = task->dd_data;
459 struct iscsi_r2t_info *r2t;
460
461 /* nothing to do for mgmt */
462 if (!task->sc)
463 return;
464
465 spin_lock_bh(&tcp_task->queue2pool);
466 /* flush task's r2t queues */
467 while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
468 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
469 sizeof(void*));
470 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
471 }
472
473 r2t = tcp_task->r2t;
474 if (r2t != NULL) {
475 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
476 sizeof(void*));
477 tcp_task->r2t = NULL;
478 }
479 spin_unlock_bh(&tcp_task->queue2pool);
480}
481EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
482
483/**
484 * iscsi_tcp_data_in - SCSI Data-In Response processing
485 * @conn: iscsi connection
486 * @task: scsi command task
487 */
488static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
489{
490 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
491 struct iscsi_tcp_task *tcp_task = task->dd_data;
492 struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
493 int datasn = be32_to_cpu(rhdr->datasn);
494 unsigned total_in_length = scsi_in(task->sc)->length;
495
496 /*
497 * lib iscsi will update this in the completion handling if there
498 * is status.
499 */
500 if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
501 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
502
503 if (tcp_conn->in.datalen == 0)
504 return 0;
505
506 if (tcp_task->exp_datasn != datasn) {
507 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
508 "\n", tcp_task->exp_datasn, datasn);
509 return ISCSI_ERR_DATASN;
510 }
511
512 tcp_task->exp_datasn++;
513
514 tcp_task->data_offset = be32_to_cpu(rhdr->offset);
515 if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
516 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
517 "total_length_in(%d)\n", tcp_task->data_offset,
518 tcp_conn->in.datalen, total_in_length);
519 return ISCSI_ERR_DATA_OFFSET;
520 }
521
522 conn->datain_pdus_cnt++;
523 return 0;
524}
525
526/**
527 * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
528 * @conn: iscsi connection
529 * @task: scsi command task
530 */
531static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
532{
533 struct iscsi_session *session = conn->session;
534 struct iscsi_tcp_task *tcp_task = task->dd_data;
535 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
536 struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
537 struct iscsi_r2t_info *r2t;
538 int r2tsn = be32_to_cpu(rhdr->r2tsn);
539 u32 data_length;
540 u32 data_offset;
541 int rc;
542
543 if (tcp_conn->in.datalen) {
544 iscsi_conn_printk(KERN_ERR, conn,
545 "invalid R2t with datalen %d\n",
546 tcp_conn->in.datalen);
547 return ISCSI_ERR_DATALEN;
548 }
549
550 if (tcp_task->exp_datasn != r2tsn){
551 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
552 tcp_task->exp_datasn, r2tsn);
553 return ISCSI_ERR_R2TSN;
554 }
555
556 /* fill-in new R2T associated with the task */
557 iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
558
559 if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
560 iscsi_conn_printk(KERN_INFO, conn,
561 "dropping R2T itt %d in recovery.\n",
562 task->itt);
563 return 0;
564 }
565
566 data_length = be32_to_cpu(rhdr->data_length);
567 if (data_length == 0) {
568 iscsi_conn_printk(KERN_ERR, conn,
569 "invalid R2T with zero data len\n");
570 return ISCSI_ERR_DATALEN;
571 }
572
573 if (data_length > session->max_burst)
574 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
575 "burst %u. Attempting to execute request.\n",
576 data_length, session->max_burst);
577
578 data_offset = be32_to_cpu(rhdr->data_offset);
579 if (data_offset + data_length > scsi_out(task->sc)->length) {
580 iscsi_conn_printk(KERN_ERR, conn,
581 "invalid R2T with data len %u at offset %u "
582 "and total length %d\n", data_length,
583 data_offset, scsi_out(task->sc)->length);
584 return ISCSI_ERR_DATALEN;
585 }
586
587 spin_lock(&tcp_task->pool2queue);
588 rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
589 if (!rc) {
590 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
591 "Target has sent more R2Ts than it "
592 "negotiated for or driver has leaked.\n");
593 spin_unlock(&tcp_task->pool2queue);
594 return ISCSI_ERR_PROTO;
595 }
596
597 r2t->exp_statsn = rhdr->statsn;
598 r2t->data_length = data_length;
599 r2t->data_offset = data_offset;
600
601 r2t->ttt = rhdr->ttt; /* no flip */
602 r2t->datasn = 0;
603 r2t->sent = 0;
604
605 tcp_task->exp_datasn = r2tsn + 1;
606 kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
607 conn->r2t_pdus_cnt++;
608 spin_unlock(&tcp_task->pool2queue);
609
610 iscsi_requeue_task(task);
611 return 0;
612}
613
614/*
615 * Handle incoming reply to DataIn command
616 */
617static int
618iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
619 struct iscsi_segment *segment)
620{
621 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
622 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
623 int rc;
624
625 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
626 return ISCSI_ERR_DATA_DGST;
627
628 /* check for non-exceptional status */
629 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
630 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
631 if (rc)
632 return rc;
633 }
634
635 iscsi_tcp_hdr_recv_prep(tcp_conn);
636 return 0;
637}
638
639/**
640 * iscsi_tcp_hdr_dissect - process PDU header
641 * @conn: iSCSI connection
642 * @hdr: PDU header
643 *
644 * This function analyzes the header of the PDU received,
645 * and performs several sanity checks. If the PDU is accompanied
646 * by data, the receive buffer is set up to copy the incoming data
647 * to the correct location.
648 */
649static int
650iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
651{
652 int rc = 0, opcode, ahslen;
653 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
654 struct iscsi_task *task;
655
656 /* verify PDU length */
657 tcp_conn->in.datalen = ntoh24(hdr->dlength);
658 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
659 iscsi_conn_printk(KERN_ERR, conn,
660 "iscsi_tcp: datalen %d > %d\n",
661 tcp_conn->in.datalen, conn->max_recv_dlength);
662 return ISCSI_ERR_DATALEN;
663 }
664
665 /* Additional header segments. So far, we don't
666 * process additional headers.
667 */
668 ahslen = hdr->hlength << 2;
669
670 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
671 /* verify itt (itt encoding: age+cid+itt) */
672 rc = iscsi_verify_itt(conn, hdr->itt);
673 if (rc)
674 return rc;
675
676 ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
677 opcode, ahslen, tcp_conn->in.datalen);
678
679 switch(opcode) {
680 case ISCSI_OP_SCSI_DATA_IN:
681 spin_lock(&conn->session->back_lock);
682 task = iscsi_itt_to_ctask(conn, hdr->itt);
683 if (!task)
684 rc = ISCSI_ERR_BAD_ITT;
685 else
686 rc = iscsi_tcp_data_in(conn, task);
687 if (rc) {
688 spin_unlock(&conn->session->back_lock);
689 break;
690 }
691
692 if (tcp_conn->in.datalen) {
693 struct iscsi_tcp_task *tcp_task = task->dd_data;
694 struct ahash_request *rx_hash = NULL;
695 struct scsi_data_buffer *sdb = scsi_in(task->sc);
696
697 /*
698 * Setup copy of Data-In into the Scsi_Cmnd
699 * Scatterlist case:
700 * We set up the iscsi_segment to point to the next
701 * scatterlist entry to copy to. As we go along,
702 * we move on to the next scatterlist entry and
703 * update the digest per-entry.
704 */
705 if (conn->datadgst_en &&
706 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
707 rx_hash = tcp_conn->rx_hash;
708
709 ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
710 "offset=%d, datalen=%d)\n",
711 tcp_task->data_offset,
712 tcp_conn->in.datalen);
713 task->last_xfer = jiffies;
714 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
715 sdb->table.sgl,
716 sdb->table.nents,
717 tcp_task->data_offset,
718 tcp_conn->in.datalen,
719 iscsi_tcp_process_data_in,
720 rx_hash);
721 spin_unlock(&conn->session->back_lock);
722 return rc;
723 }
724 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
725 spin_unlock(&conn->session->back_lock);
726 break;
727 case ISCSI_OP_SCSI_CMD_RSP:
728 if (tcp_conn->in.datalen) {
729 iscsi_tcp_data_recv_prep(tcp_conn);
730 return 0;
731 }
732 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
733 break;
734 case ISCSI_OP_R2T:
735 spin_lock(&conn->session->back_lock);
736 task = iscsi_itt_to_ctask(conn, hdr->itt);
737 spin_unlock(&conn->session->back_lock);
738 if (!task)
739 rc = ISCSI_ERR_BAD_ITT;
740 else if (ahslen)
741 rc = ISCSI_ERR_AHSLEN;
742 else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
743 task->last_xfer = jiffies;
744 spin_lock(&conn->session->frwd_lock);
745 rc = iscsi_tcp_r2t_rsp(conn, task);
746 spin_unlock(&conn->session->frwd_lock);
747 } else
748 rc = ISCSI_ERR_PROTO;
749 break;
750 case ISCSI_OP_LOGIN_RSP:
751 case ISCSI_OP_TEXT_RSP:
752 case ISCSI_OP_REJECT:
753 case ISCSI_OP_ASYNC_EVENT:
754 /*
755 * It is possible that we could get a PDU with a buffer larger
756 * than 8K, but there are no targets that currently do this.
757 * For now we fail until we find a vendor that needs it
758 */
759 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
760 iscsi_conn_printk(KERN_ERR, conn,
761 "iscsi_tcp: received buffer of "
762 "len %u but conn buffer is only %u "
763 "(opcode %0x)\n",
764 tcp_conn->in.datalen,
765 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
766 rc = ISCSI_ERR_PROTO;
767 break;
768 }
769
770 /* If there's data coming in with the response,
771 * receive it to the connection's buffer.
772 */
773 if (tcp_conn->in.datalen) {
774 iscsi_tcp_data_recv_prep(tcp_conn);
775 return 0;
776 }
777 /* fall through */
778 case ISCSI_OP_LOGOUT_RSP:
779 case ISCSI_OP_NOOP_IN:
780 case ISCSI_OP_SCSI_TMFUNC_RSP:
781 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
782 break;
783 default:
784 rc = ISCSI_ERR_BAD_OPCODE;
785 break;
786 }
787
788 if (rc == 0) {
789 /* Anything that comes with data should have
790 * been handled above. */
791 if (tcp_conn->in.datalen)
792 return ISCSI_ERR_PROTO;
793 iscsi_tcp_hdr_recv_prep(tcp_conn);
794 }
795
796 return rc;
797}
798
799/**
800 * iscsi_tcp_hdr_recv_done - process PDU header
801 * @tcp_conn: iSCSI TCP connection
802 * @segment: the buffer segment being processed
803 *
804 * This is the callback invoked when the PDU header has
805 * been received. If the header is followed by additional
806 * header segments, we go back for more data.
807 */
808static int
809iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
810 struct iscsi_segment *segment)
811{
812 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
813 struct iscsi_hdr *hdr;
814
815 /* Check if there are additional header segments
816 * *prior* to computing the digest, because we
817 * may need to go back to the caller for more.
818 */
819 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
820 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
821 /* Bump the header length - the caller will
822 * just loop around and get the AHS for us, and
823 * call again. */
824 unsigned int ahslen = hdr->hlength << 2;
825
826 /* Make sure we don't overflow */
827 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
828 return ISCSI_ERR_AHSLEN;
829
830 segment->total_size += ahslen;
831 segment->size += ahslen;
832 return 0;
833 }
834
835 /* We're done processing the header. See if we're doing
836 * header digests; if so, set up the recv_digest buffer
837 * and go back for more. */
838 if (conn->hdrdgst_en &&
839 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
840 if (segment->digest_len == 0) {
841 /*
842 * Even if we offload the digest processing we
843 * splice it in so we can increment the skb/segment
844 * counters in preparation for the data segment.
845 */
846 iscsi_tcp_segment_splice_digest(segment,
847 segment->recv_digest);
848 return 0;
849 }
850
851 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
852 segment->total_copied - ISCSI_DIGEST_SIZE,
853 segment->digest);
854
855 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
856 return ISCSI_ERR_HDR_DGST;
857 }
858
859 tcp_conn->in.hdr = hdr;
860 return iscsi_tcp_hdr_dissect(conn, hdr);
861}
862
863/**
864 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
865 * @tcp_conn: iscsi tcp conn
866 *
867 * returns non zero if we are currently processing or setup to process
868 * a header.
869 */
870inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
871{
872 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
873}
874EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
875
876/**
877 * iscsi_tcp_recv_skb - Process skb
878 * @conn: iscsi connection
879 * @skb: network buffer with header and/or data segment
880 * @offset: offset in skb
881 * @offloaded: bool indicating if transfer was offloaded
882 * @status: iscsi TCP status result
883 *
884 * Will return status of transfer in @status. And will return
885 * number of bytes copied.
886 */
887int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
888 unsigned int offset, bool offloaded, int *status)
889{
890 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
891 struct iscsi_segment *segment = &tcp_conn->in.segment;
892 struct skb_seq_state seq;
893 unsigned int consumed = 0;
894 int rc = 0;
895
896 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
897 /*
898 * Update for each skb instead of pdu, because over slow networks a
899 * data_in's data could take a while to read in. We also want to
900 * account for r2ts.
901 */
902 conn->last_recv = jiffies;
903
904 if (unlikely(conn->suspend_rx)) {
905 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
906 *status = ISCSI_TCP_SUSPENDED;
907 return 0;
908 }
909
910 if (offloaded) {
911 segment->total_copied = segment->total_size;
912 goto segment_done;
913 }
914
915 skb_prepare_seq_read(skb, offset, skb->len, &seq);
916 while (1) {
917 unsigned int avail;
918 const u8 *ptr;
919
920 avail = skb_seq_read(consumed, &ptr, &seq);
921 if (avail == 0) {
922 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
923 consumed);
924 *status = ISCSI_TCP_SKB_DONE;
925 goto skb_done;
926 }
927 BUG_ON(segment->copied >= segment->size);
928
929 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
930 avail);
931 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
932 BUG_ON(rc == 0);
933 consumed += rc;
934
935 if (segment->total_copied >= segment->total_size) {
936 skb_abort_seq_read(&seq);
937 goto segment_done;
938 }
939 }
940
941segment_done:
942 *status = ISCSI_TCP_SEGMENT_DONE;
943 ISCSI_DBG_TCP(conn, "segment done\n");
944 rc = segment->done(tcp_conn, segment);
945 if (rc != 0) {
946 *status = ISCSI_TCP_CONN_ERR;
947 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
948 iscsi_conn_failure(conn, rc);
949 return 0;
950 }
951 /* The done() functions sets up the next segment. */
952
953skb_done:
954 conn->rxdata_octets += consumed;
955 return consumed;
956}
957EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
958
959/**
960 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
961 * @task: scsi command task
962 */
963int iscsi_tcp_task_init(struct iscsi_task *task)
964{
965 struct iscsi_tcp_task *tcp_task = task->dd_data;
966 struct iscsi_conn *conn = task->conn;
967 struct scsi_cmnd *sc = task->sc;
968 int err;
969
970 if (!sc) {
971 /*
972 * mgmt tasks do not have a scatterlist since they come
973 * in from the iscsi interface.
974 */
975 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
976
977 return conn->session->tt->init_pdu(task, 0, task->data_count);
978 }
979
980 BUG_ON(kfifo_len(&tcp_task->r2tqueue));
981 tcp_task->exp_datasn = 0;
982
983 /* Prepare PDU, optionally w/ immediate data */
984 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
985 task->itt, task->imm_count, task->unsol_r2t.data_length);
986
987 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
988 if (err)
989 return err;
990 task->imm_count = 0;
991 return 0;
992}
993EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
994
995static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
996{
997 struct iscsi_tcp_task *tcp_task = task->dd_data;
998 struct iscsi_r2t_info *r2t = NULL;
999
1000 if (iscsi_task_has_unsol_data(task))
1001 r2t = &task->unsol_r2t;
1002 else {
1003 spin_lock_bh(&tcp_task->queue2pool);
1004 if (tcp_task->r2t) {
1005 r2t = tcp_task->r2t;
1006 /* Continue with this R2T? */
1007 if (r2t->data_length <= r2t->sent) {
1008 ISCSI_DBG_TCP(task->conn,
1009 " done with r2t %p\n", r2t);
1010 kfifo_in(&tcp_task->r2tpool.queue,
1011 (void *)&tcp_task->r2t,
1012 sizeof(void *));
1013 tcp_task->r2t = r2t = NULL;
1014 }
1015 }
1016
1017 if (r2t == NULL) {
1018 if (kfifo_out(&tcp_task->r2tqueue,
1019 (void *)&tcp_task->r2t, sizeof(void *)) !=
1020 sizeof(void *))
1021 r2t = NULL;
1022 else
1023 r2t = tcp_task->r2t;
1024 }
1025 spin_unlock_bh(&tcp_task->queue2pool);
1026 }
1027
1028 return r2t;
1029}
1030
1031/**
1032 * iscsi_tcp_task_xmit - xmit normal PDU task
1033 * @task: iscsi command task
1034 *
1035 * We're expected to return 0 when everything was transmitted successfully,
1036 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1037 * of error.
1038 */
1039int iscsi_tcp_task_xmit(struct iscsi_task *task)
1040{
1041 struct iscsi_conn *conn = task->conn;
1042 struct iscsi_session *session = conn->session;
1043 struct iscsi_r2t_info *r2t;
1044 int rc = 0;
1045
1046flush:
1047 /* Flush any pending data first. */
1048 rc = session->tt->xmit_pdu(task);
1049 if (rc < 0)
1050 return rc;
1051
1052 /* mgmt command */
1053 if (!task->sc) {
1054 if (task->hdr->itt == RESERVED_ITT)
1055 iscsi_put_task(task);
1056 return 0;
1057 }
1058
1059 /* Are we done already? */
1060 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1061 return 0;
1062
1063 r2t = iscsi_tcp_get_curr_r2t(task);
1064 if (r2t == NULL) {
1065 /* Waiting for more R2Ts to arrive. */
1066 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1067 return 0;
1068 }
1069
1070 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1071 if (rc)
1072 return rc;
1073 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1074
1075 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1076 r2t, r2t->datasn - 1, task->hdr->itt,
1077 r2t->data_offset + r2t->sent, r2t->data_count);
1078
1079 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1080 r2t->data_count);
1081 if (rc) {
1082 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1083 return rc;
1084 }
1085
1086 r2t->sent += r2t->data_count;
1087 goto flush;
1088}
1089EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1090
1091struct iscsi_cls_conn *
1092iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1093 uint32_t conn_idx)
1094
1095{
1096 struct iscsi_conn *conn;
1097 struct iscsi_cls_conn *cls_conn;
1098 struct iscsi_tcp_conn *tcp_conn;
1099
1100 cls_conn = iscsi_conn_setup(cls_session,
1101 sizeof(*tcp_conn) + dd_data_size, conn_idx);
1102 if (!cls_conn)
1103 return NULL;
1104 conn = cls_conn->dd_data;
1105 /*
1106 * due to strange issues with iser these are not set
1107 * in iscsi_conn_setup
1108 */
1109 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1110
1111 tcp_conn = conn->dd_data;
1112 tcp_conn->iscsi_conn = conn;
1113 tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1114 return cls_conn;
1115}
1116EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1117
1118void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1119{
1120 iscsi_conn_teardown(cls_conn);
1121}
1122EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1123
1124int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1125{
1126 int i;
1127 int cmd_i;
1128
1129 /*
1130 * initialize per-task: R2T pool and xmit queue
1131 */
1132 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1133 struct iscsi_task *task = session->cmds[cmd_i];
1134 struct iscsi_tcp_task *tcp_task = task->dd_data;
1135
1136 /*
1137 * pre-allocated x2 as much r2ts to handle race when
1138 * target acks DataOut faster than we data_xmit() queues
1139 * could replenish r2tqueue.
1140 */
1141
1142 /* R2T pool */
1143 if (iscsi_pool_init(&tcp_task->r2tpool,
1144 session->max_r2t * 2, NULL,
1145 sizeof(struct iscsi_r2t_info))) {
1146 goto r2t_alloc_fail;
1147 }
1148
1149 /* R2T xmit queue */
1150 if (kfifo_alloc(&tcp_task->r2tqueue,
1151 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1152 iscsi_pool_free(&tcp_task->r2tpool);
1153 goto r2t_alloc_fail;
1154 }
1155 spin_lock_init(&tcp_task->pool2queue);
1156 spin_lock_init(&tcp_task->queue2pool);
1157 }
1158
1159 return 0;
1160
1161r2t_alloc_fail:
1162 for (i = 0; i < cmd_i; i++) {
1163 struct iscsi_task *task = session->cmds[i];
1164 struct iscsi_tcp_task *tcp_task = task->dd_data;
1165
1166 kfifo_free(&tcp_task->r2tqueue);
1167 iscsi_pool_free(&tcp_task->r2tpool);
1168 }
1169 return -ENOMEM;
1170}
1171EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1172
1173void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1174{
1175 int i;
1176
1177 for (i = 0; i < session->cmds_max; i++) {
1178 struct iscsi_task *task = session->cmds[i];
1179 struct iscsi_tcp_task *tcp_task = task->dd_data;
1180
1181 kfifo_free(&tcp_task->r2tqueue);
1182 iscsi_pool_free(&tcp_task->r2tpool);
1183 }
1184}
1185EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1186
1187int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1188{
1189 struct iscsi_session *session = conn->session;
1190 unsigned short r2ts = 0;
1191
1192 sscanf(buf, "%hu", &r2ts);
1193 if (session->max_r2t == r2ts)
1194 return 0;
1195
1196 if (!r2ts || !is_power_of_2(r2ts))
1197 return -EINVAL;
1198
1199 session->max_r2t = r2ts;
1200 iscsi_tcp_r2tpool_free(session);
1201 return iscsi_tcp_r2tpool_alloc(session);
1202}
1203EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1204
1205void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1206 struct iscsi_stats *stats)
1207{
1208 struct iscsi_conn *conn = cls_conn->dd_data;
1209
1210 stats->txdata_octets = conn->txdata_octets;
1211 stats->rxdata_octets = conn->rxdata_octets;
1212 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1213 stats->dataout_pdus = conn->dataout_pdus_cnt;
1214 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1215 stats->datain_pdus = conn->datain_pdus_cnt;
1216 stats->r2t_pdus = conn->r2t_pdus_cnt;
1217 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1218 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1219}
1220EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);