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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 *
802 * This is the callback invoked when the PDU header has
803 * been received. If the header is followed by additional
804 * header segments, we go back for more data.
805 */
806static int
807iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
808 struct iscsi_segment *segment)
809{
810 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
811 struct iscsi_hdr *hdr;
812
813 /* Check if there are additional header segments
814 * *prior* to computing the digest, because we
815 * may need to go back to the caller for more.
816 */
817 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
818 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
819 /* Bump the header length - the caller will
820 * just loop around and get the AHS for us, and
821 * call again. */
822 unsigned int ahslen = hdr->hlength << 2;
823
824 /* Make sure we don't overflow */
825 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
826 return ISCSI_ERR_AHSLEN;
827
828 segment->total_size += ahslen;
829 segment->size += ahslen;
830 return 0;
831 }
832
833 /* We're done processing the header. See if we're doing
834 * header digests; if so, set up the recv_digest buffer
835 * and go back for more. */
836 if (conn->hdrdgst_en &&
837 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
838 if (segment->digest_len == 0) {
839 /*
840 * Even if we offload the digest processing we
841 * splice it in so we can increment the skb/segment
842 * counters in preparation for the data segment.
843 */
844 iscsi_tcp_segment_splice_digest(segment,
845 segment->recv_digest);
846 return 0;
847 }
848
849 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
850 segment->total_copied - ISCSI_DIGEST_SIZE,
851 segment->digest);
852
853 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
854 return ISCSI_ERR_HDR_DGST;
855 }
856
857 tcp_conn->in.hdr = hdr;
858 return iscsi_tcp_hdr_dissect(conn, hdr);
859}
860
861/**
862 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
863 * @tcp_conn: iscsi tcp conn
864 *
865 * returns non zero if we are currently processing or setup to process
866 * a header.
867 */
868inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
869{
870 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
871}
872EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
873
874/**
875 * iscsi_tcp_recv_skb - Process skb
876 * @conn: iscsi connection
877 * @skb: network buffer with header and/or data segment
878 * @offset: offset in skb
879 * @offload: bool indicating if transfer was offloaded
880 *
881 * Will return status of transfer in status. And will return
882 * number of bytes copied.
883 */
884int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
885 unsigned int offset, bool offloaded, int *status)
886{
887 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
888 struct iscsi_segment *segment = &tcp_conn->in.segment;
889 struct skb_seq_state seq;
890 unsigned int consumed = 0;
891 int rc = 0;
892
893 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
894 /*
895 * Update for each skb instead of pdu, because over slow networks a
896 * data_in's data could take a while to read in. We also want to
897 * account for r2ts.
898 */
899 conn->last_recv = jiffies;
900
901 if (unlikely(conn->suspend_rx)) {
902 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
903 *status = ISCSI_TCP_SUSPENDED;
904 return 0;
905 }
906
907 if (offloaded) {
908 segment->total_copied = segment->total_size;
909 goto segment_done;
910 }
911
912 skb_prepare_seq_read(skb, offset, skb->len, &seq);
913 while (1) {
914 unsigned int avail;
915 const u8 *ptr;
916
917 avail = skb_seq_read(consumed, &ptr, &seq);
918 if (avail == 0) {
919 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
920 consumed);
921 *status = ISCSI_TCP_SKB_DONE;
922 goto skb_done;
923 }
924 BUG_ON(segment->copied >= segment->size);
925
926 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
927 avail);
928 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
929 BUG_ON(rc == 0);
930 consumed += rc;
931
932 if (segment->total_copied >= segment->total_size) {
933 skb_abort_seq_read(&seq);
934 goto segment_done;
935 }
936 }
937
938segment_done:
939 *status = ISCSI_TCP_SEGMENT_DONE;
940 ISCSI_DBG_TCP(conn, "segment done\n");
941 rc = segment->done(tcp_conn, segment);
942 if (rc != 0) {
943 *status = ISCSI_TCP_CONN_ERR;
944 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
945 iscsi_conn_failure(conn, rc);
946 return 0;
947 }
948 /* The done() functions sets up the next segment. */
949
950skb_done:
951 conn->rxdata_octets += consumed;
952 return consumed;
953}
954EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
955
956/**
957 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
958 * @conn: iscsi connection
959 * @task: scsi command task
960 * @sc: scsi command
961 */
962int iscsi_tcp_task_init(struct iscsi_task *task)
963{
964 struct iscsi_tcp_task *tcp_task = task->dd_data;
965 struct iscsi_conn *conn = task->conn;
966 struct scsi_cmnd *sc = task->sc;
967 int err;
968
969 if (!sc) {
970 /*
971 * mgmt tasks do not have a scatterlist since they come
972 * in from the iscsi interface.
973 */
974 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
975
976 return conn->session->tt->init_pdu(task, 0, task->data_count);
977 }
978
979 BUG_ON(kfifo_len(&tcp_task->r2tqueue));
980 tcp_task->exp_datasn = 0;
981
982 /* Prepare PDU, optionally w/ immediate data */
983 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
984 task->itt, task->imm_count, task->unsol_r2t.data_length);
985
986 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
987 if (err)
988 return err;
989 task->imm_count = 0;
990 return 0;
991}
992EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
993
994static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
995{
996 struct iscsi_tcp_task *tcp_task = task->dd_data;
997 struct iscsi_r2t_info *r2t = NULL;
998
999 if (iscsi_task_has_unsol_data(task))
1000 r2t = &task->unsol_r2t;
1001 else {
1002 spin_lock_bh(&tcp_task->queue2pool);
1003 if (tcp_task->r2t) {
1004 r2t = tcp_task->r2t;
1005 /* Continue with this R2T? */
1006 if (r2t->data_length <= r2t->sent) {
1007 ISCSI_DBG_TCP(task->conn,
1008 " done with r2t %p\n", r2t);
1009 kfifo_in(&tcp_task->r2tpool.queue,
1010 (void *)&tcp_task->r2t,
1011 sizeof(void *));
1012 tcp_task->r2t = r2t = NULL;
1013 }
1014 }
1015
1016 if (r2t == NULL) {
1017 if (kfifo_out(&tcp_task->r2tqueue,
1018 (void *)&tcp_task->r2t, sizeof(void *)) !=
1019 sizeof(void *))
1020 r2t = NULL;
1021 else
1022 r2t = tcp_task->r2t;
1023 }
1024 spin_unlock_bh(&tcp_task->queue2pool);
1025 }
1026
1027 return r2t;
1028}
1029
1030/**
1031 * iscsi_tcp_task_xmit - xmit normal PDU task
1032 * @task: iscsi command task
1033 *
1034 * We're expected to return 0 when everything was transmitted successfully,
1035 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1036 * of error.
1037 */
1038int iscsi_tcp_task_xmit(struct iscsi_task *task)
1039{
1040 struct iscsi_conn *conn = task->conn;
1041 struct iscsi_session *session = conn->session;
1042 struct iscsi_r2t_info *r2t;
1043 int rc = 0;
1044
1045flush:
1046 /* Flush any pending data first. */
1047 rc = session->tt->xmit_pdu(task);
1048 if (rc < 0)
1049 return rc;
1050
1051 /* mgmt command */
1052 if (!task->sc) {
1053 if (task->hdr->itt == RESERVED_ITT)
1054 iscsi_put_task(task);
1055 return 0;
1056 }
1057
1058 /* Are we done already? */
1059 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1060 return 0;
1061
1062 r2t = iscsi_tcp_get_curr_r2t(task);
1063 if (r2t == NULL) {
1064 /* Waiting for more R2Ts to arrive. */
1065 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1066 return 0;
1067 }
1068
1069 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1070 if (rc)
1071 return rc;
1072 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1073
1074 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1075 r2t, r2t->datasn - 1, task->hdr->itt,
1076 r2t->data_offset + r2t->sent, r2t->data_count);
1077
1078 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1079 r2t->data_count);
1080 if (rc) {
1081 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1082 return rc;
1083 }
1084
1085 r2t->sent += r2t->data_count;
1086 goto flush;
1087}
1088EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1089
1090struct iscsi_cls_conn *
1091iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1092 uint32_t conn_idx)
1093
1094{
1095 struct iscsi_conn *conn;
1096 struct iscsi_cls_conn *cls_conn;
1097 struct iscsi_tcp_conn *tcp_conn;
1098
1099 cls_conn = iscsi_conn_setup(cls_session,
1100 sizeof(*tcp_conn) + dd_data_size, conn_idx);
1101 if (!cls_conn)
1102 return NULL;
1103 conn = cls_conn->dd_data;
1104 /*
1105 * due to strange issues with iser these are not set
1106 * in iscsi_conn_setup
1107 */
1108 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1109
1110 tcp_conn = conn->dd_data;
1111 tcp_conn->iscsi_conn = conn;
1112 tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1113 return cls_conn;
1114}
1115EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1116
1117void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1118{
1119 iscsi_conn_teardown(cls_conn);
1120}
1121EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1122
1123int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1124{
1125 int i;
1126 int cmd_i;
1127
1128 /*
1129 * initialize per-task: R2T pool and xmit queue
1130 */
1131 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1132 struct iscsi_task *task = session->cmds[cmd_i];
1133 struct iscsi_tcp_task *tcp_task = task->dd_data;
1134
1135 /*
1136 * pre-allocated x2 as much r2ts to handle race when
1137 * target acks DataOut faster than we data_xmit() queues
1138 * could replenish r2tqueue.
1139 */
1140
1141 /* R2T pool */
1142 if (iscsi_pool_init(&tcp_task->r2tpool,
1143 session->max_r2t * 2, NULL,
1144 sizeof(struct iscsi_r2t_info))) {
1145 goto r2t_alloc_fail;
1146 }
1147
1148 /* R2T xmit queue */
1149 if (kfifo_alloc(&tcp_task->r2tqueue,
1150 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1151 iscsi_pool_free(&tcp_task->r2tpool);
1152 goto r2t_alloc_fail;
1153 }
1154 spin_lock_init(&tcp_task->pool2queue);
1155 spin_lock_init(&tcp_task->queue2pool);
1156 }
1157
1158 return 0;
1159
1160r2t_alloc_fail:
1161 for (i = 0; i < cmd_i; i++) {
1162 struct iscsi_task *task = session->cmds[i];
1163 struct iscsi_tcp_task *tcp_task = task->dd_data;
1164
1165 kfifo_free(&tcp_task->r2tqueue);
1166 iscsi_pool_free(&tcp_task->r2tpool);
1167 }
1168 return -ENOMEM;
1169}
1170EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1171
1172void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1173{
1174 int i;
1175
1176 for (i = 0; i < session->cmds_max; i++) {
1177 struct iscsi_task *task = session->cmds[i];
1178 struct iscsi_tcp_task *tcp_task = task->dd_data;
1179
1180 kfifo_free(&tcp_task->r2tqueue);
1181 iscsi_pool_free(&tcp_task->r2tpool);
1182 }
1183}
1184EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1185
1186int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1187{
1188 struct iscsi_session *session = conn->session;
1189 unsigned short r2ts = 0;
1190
1191 sscanf(buf, "%hu", &r2ts);
1192 if (session->max_r2t == r2ts)
1193 return 0;
1194
1195 if (!r2ts || !is_power_of_2(r2ts))
1196 return -EINVAL;
1197
1198 session->max_r2t = r2ts;
1199 iscsi_tcp_r2tpool_free(session);
1200 return iscsi_tcp_r2tpool_alloc(session);
1201}
1202EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1203
1204void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1205 struct iscsi_stats *stats)
1206{
1207 struct iscsi_conn *conn = cls_conn->dd_data;
1208
1209 stats->txdata_octets = conn->txdata_octets;
1210 stats->rxdata_octets = conn->rxdata_octets;
1211 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1212 stats->dataout_pdus = conn->dataout_pdus_cnt;
1213 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1214 stats->datain_pdus = conn->datain_pdus_cnt;
1215 stats->r2t_pdus = conn->r2t_pdus_cnt;
1216 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1217 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1218}
1219EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);
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 __iscsi_get_task(task);
562
563 tcp_conn = conn->dd_data;
564 rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
565 /* fill-in new R2T associated with the task */
566 iscsi_update_cmdsn(session, (struct iscsi_nopin *)rhdr);
567 spin_unlock(&session->back_lock);
568
569 if (tcp_conn->in.datalen) {
570 iscsi_conn_printk(KERN_ERR, conn,
571 "invalid R2t with datalen %d\n",
572 tcp_conn->in.datalen);
573 rc = ISCSI_ERR_DATALEN;
574 goto put_task;
575 }
576
577 tcp_task = task->dd_data;
578 r2tsn = be32_to_cpu(rhdr->r2tsn);
579 if (tcp_task->exp_datasn != r2tsn){
580 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
581 tcp_task->exp_datasn, r2tsn);
582 rc = ISCSI_ERR_R2TSN;
583 goto put_task;
584 }
585
586 if (session->state != ISCSI_STATE_LOGGED_IN) {
587 iscsi_conn_printk(KERN_INFO, conn,
588 "dropping R2T itt %d in recovery.\n",
589 task->itt);
590 rc = 0;
591 goto put_task;
592 }
593
594 data_length = be32_to_cpu(rhdr->data_length);
595 if (data_length == 0) {
596 iscsi_conn_printk(KERN_ERR, conn,
597 "invalid R2T with zero data len\n");
598 rc = ISCSI_ERR_DATALEN;
599 goto put_task;
600 }
601
602 if (data_length > session->max_burst)
603 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
604 "burst %u. Attempting to execute request.\n",
605 data_length, session->max_burst);
606
607 data_offset = be32_to_cpu(rhdr->data_offset);
608 if (data_offset + data_length > task->sc->sdb.length) {
609 iscsi_conn_printk(KERN_ERR, conn,
610 "invalid R2T with data len %u at offset %u "
611 "and total length %d\n", data_length,
612 data_offset, task->sc->sdb.length);
613 rc = ISCSI_ERR_DATALEN;
614 goto put_task;
615 }
616
617 spin_lock(&tcp_task->pool2queue);
618 rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
619 if (!rc) {
620 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
621 "Target has sent more R2Ts than it "
622 "negotiated for or driver has leaked.\n");
623 spin_unlock(&tcp_task->pool2queue);
624 rc = ISCSI_ERR_PROTO;
625 goto put_task;
626 }
627
628 r2t->exp_statsn = rhdr->statsn;
629 r2t->data_length = data_length;
630 r2t->data_offset = data_offset;
631
632 r2t->ttt = rhdr->ttt; /* no flip */
633 r2t->datasn = 0;
634 r2t->sent = 0;
635
636 tcp_task->exp_datasn = r2tsn + 1;
637 kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
638 conn->r2t_pdus_cnt++;
639 spin_unlock(&tcp_task->pool2queue);
640
641 iscsi_requeue_task(task);
642 return 0;
643
644put_task:
645 iscsi_put_task(task);
646 return rc;
647}
648
649/*
650 * Handle incoming reply to DataIn command
651 */
652static int
653iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
654 struct iscsi_segment *segment)
655{
656 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
657 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
658 int rc;
659
660 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
661 return ISCSI_ERR_DATA_DGST;
662
663 /* check for non-exceptional status */
664 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
665 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
666 if (rc)
667 return rc;
668 }
669
670 iscsi_tcp_hdr_recv_prep(tcp_conn);
671 return 0;
672}
673
674/**
675 * iscsi_tcp_hdr_dissect - process PDU header
676 * @conn: iSCSI connection
677 * @hdr: PDU header
678 *
679 * This function analyzes the header of the PDU received,
680 * and performs several sanity checks. If the PDU is accompanied
681 * by data, the receive buffer is set up to copy the incoming data
682 * to the correct location.
683 */
684static int
685iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
686{
687 int rc = 0, opcode, ahslen;
688 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
689 struct iscsi_task *task;
690
691 /* verify PDU length */
692 tcp_conn->in.datalen = ntoh24(hdr->dlength);
693 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
694 iscsi_conn_printk(KERN_ERR, conn,
695 "iscsi_tcp: datalen %d > %d\n",
696 tcp_conn->in.datalen, conn->max_recv_dlength);
697 return ISCSI_ERR_DATALEN;
698 }
699
700 /* Additional header segments. So far, we don't
701 * process additional headers.
702 */
703 ahslen = hdr->hlength << 2;
704
705 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
706 /* verify itt (itt encoding: age+cid+itt) */
707 rc = iscsi_verify_itt(conn, hdr->itt);
708 if (rc)
709 return rc;
710
711 ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
712 opcode, ahslen, tcp_conn->in.datalen);
713
714 switch(opcode) {
715 case ISCSI_OP_SCSI_DATA_IN:
716 spin_lock(&conn->session->back_lock);
717 task = iscsi_itt_to_ctask(conn, hdr->itt);
718 if (!task)
719 rc = ISCSI_ERR_BAD_ITT;
720 else
721 rc = iscsi_tcp_data_in(conn, task);
722 if (rc) {
723 spin_unlock(&conn->session->back_lock);
724 break;
725 }
726
727 if (tcp_conn->in.datalen) {
728 struct iscsi_tcp_task *tcp_task = task->dd_data;
729 struct ahash_request *rx_hash = NULL;
730 struct scsi_data_buffer *sdb = &task->sc->sdb;
731
732 /*
733 * Setup copy of Data-In into the struct scsi_cmnd
734 * Scatterlist case:
735 * We set up the iscsi_segment to point to the next
736 * scatterlist entry to copy to. As we go along,
737 * we move on to the next scatterlist entry and
738 * update the digest per-entry.
739 */
740 if (conn->datadgst_en &&
741 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
742 rx_hash = tcp_conn->rx_hash;
743
744 ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
745 "offset=%d, datalen=%d)\n",
746 tcp_task->data_offset,
747 tcp_conn->in.datalen);
748 task->last_xfer = jiffies;
749 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
750 sdb->table.sgl,
751 sdb->table.nents,
752 tcp_task->data_offset,
753 tcp_conn->in.datalen,
754 iscsi_tcp_process_data_in,
755 rx_hash);
756 spin_unlock(&conn->session->back_lock);
757 return rc;
758 }
759 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
760 spin_unlock(&conn->session->back_lock);
761 break;
762 case ISCSI_OP_SCSI_CMD_RSP:
763 if (tcp_conn->in.datalen) {
764 iscsi_tcp_data_recv_prep(tcp_conn);
765 return 0;
766 }
767 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
768 break;
769 case ISCSI_OP_R2T:
770 if (ahslen) {
771 rc = ISCSI_ERR_AHSLEN;
772 break;
773 }
774 rc = iscsi_tcp_r2t_rsp(conn, hdr);
775 break;
776 case ISCSI_OP_LOGIN_RSP:
777 case ISCSI_OP_TEXT_RSP:
778 case ISCSI_OP_REJECT:
779 case ISCSI_OP_ASYNC_EVENT:
780 /*
781 * It is possible that we could get a PDU with a buffer larger
782 * than 8K, but there are no targets that currently do this.
783 * For now we fail until we find a vendor that needs it
784 */
785 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
786 iscsi_conn_printk(KERN_ERR, conn,
787 "iscsi_tcp: received buffer of "
788 "len %u but conn buffer is only %u "
789 "(opcode %0x)\n",
790 tcp_conn->in.datalen,
791 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
792 rc = ISCSI_ERR_PROTO;
793 break;
794 }
795
796 /* If there's data coming in with the response,
797 * receive it to the connection's buffer.
798 */
799 if (tcp_conn->in.datalen) {
800 iscsi_tcp_data_recv_prep(tcp_conn);
801 return 0;
802 }
803 fallthrough;
804 case ISCSI_OP_LOGOUT_RSP:
805 case ISCSI_OP_NOOP_IN:
806 case ISCSI_OP_SCSI_TMFUNC_RSP:
807 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
808 break;
809 default:
810 rc = ISCSI_ERR_BAD_OPCODE;
811 break;
812 }
813
814 if (rc == 0) {
815 /* Anything that comes with data should have
816 * been handled above. */
817 if (tcp_conn->in.datalen)
818 return ISCSI_ERR_PROTO;
819 iscsi_tcp_hdr_recv_prep(tcp_conn);
820 }
821
822 return rc;
823}
824
825/**
826 * iscsi_tcp_hdr_recv_done - process PDU header
827 * @tcp_conn: iSCSI TCP connection
828 * @segment: the buffer segment being processed
829 *
830 * This is the callback invoked when the PDU header has
831 * been received. If the header is followed by additional
832 * header segments, we go back for more data.
833 */
834static int
835iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
836 struct iscsi_segment *segment)
837{
838 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
839 struct iscsi_hdr *hdr;
840
841 /* Check if there are additional header segments
842 * *prior* to computing the digest, because we
843 * may need to go back to the caller for more.
844 */
845 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
846 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
847 /* Bump the header length - the caller will
848 * just loop around and get the AHS for us, and
849 * call again. */
850 unsigned int ahslen = hdr->hlength << 2;
851
852 /* Make sure we don't overflow */
853 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
854 return ISCSI_ERR_AHSLEN;
855
856 segment->total_size += ahslen;
857 segment->size += ahslen;
858 return 0;
859 }
860
861 /* We're done processing the header. See if we're doing
862 * header digests; if so, set up the recv_digest buffer
863 * and go back for more. */
864 if (conn->hdrdgst_en &&
865 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
866 if (segment->digest_len == 0) {
867 /*
868 * Even if we offload the digest processing we
869 * splice it in so we can increment the skb/segment
870 * counters in preparation for the data segment.
871 */
872 iscsi_tcp_segment_splice_digest(segment,
873 segment->recv_digest);
874 return 0;
875 }
876
877 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
878 segment->total_copied - ISCSI_DIGEST_SIZE,
879 segment->digest);
880
881 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
882 return ISCSI_ERR_HDR_DGST;
883 }
884
885 tcp_conn->in.hdr = hdr;
886 return iscsi_tcp_hdr_dissect(conn, hdr);
887}
888
889/**
890 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
891 * @tcp_conn: iscsi tcp conn
892 *
893 * returns non zero if we are currently processing or setup to process
894 * a header.
895 */
896inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
897{
898 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
899}
900EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
901
902/**
903 * iscsi_tcp_recv_skb - Process skb
904 * @conn: iscsi connection
905 * @skb: network buffer with header and/or data segment
906 * @offset: offset in skb
907 * @offloaded: bool indicating if transfer was offloaded
908 * @status: iscsi TCP status result
909 *
910 * Will return status of transfer in @status. And will return
911 * number of bytes copied.
912 */
913int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
914 unsigned int offset, bool offloaded, int *status)
915{
916 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
917 struct iscsi_segment *segment = &tcp_conn->in.segment;
918 struct skb_seq_state seq;
919 unsigned int consumed = 0;
920 int rc = 0;
921
922 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
923 /*
924 * Update for each skb instead of pdu, because over slow networks a
925 * data_in's data could take a while to read in. We also want to
926 * account for r2ts.
927 */
928 conn->last_recv = jiffies;
929
930 if (unlikely(conn->suspend_rx)) {
931 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
932 *status = ISCSI_TCP_SUSPENDED;
933 return 0;
934 }
935
936 if (offloaded) {
937 segment->total_copied = segment->total_size;
938 goto segment_done;
939 }
940
941 skb_prepare_seq_read(skb, offset, skb->len, &seq);
942 while (1) {
943 unsigned int avail;
944 const u8 *ptr;
945
946 avail = skb_seq_read(consumed, &ptr, &seq);
947 if (avail == 0) {
948 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
949 consumed);
950 *status = ISCSI_TCP_SKB_DONE;
951 goto skb_done;
952 }
953 BUG_ON(segment->copied >= segment->size);
954
955 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
956 avail);
957 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
958 BUG_ON(rc == 0);
959 consumed += rc;
960
961 if (segment->total_copied >= segment->total_size) {
962 skb_abort_seq_read(&seq);
963 goto segment_done;
964 }
965 }
966
967segment_done:
968 *status = ISCSI_TCP_SEGMENT_DONE;
969 ISCSI_DBG_TCP(conn, "segment done\n");
970 rc = segment->done(tcp_conn, segment);
971 if (rc != 0) {
972 *status = ISCSI_TCP_CONN_ERR;
973 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
974 iscsi_conn_failure(conn, rc);
975 return 0;
976 }
977 /* The done() functions sets up the next segment. */
978
979skb_done:
980 conn->rxdata_octets += consumed;
981 return consumed;
982}
983EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
984
985/**
986 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
987 * @task: scsi command task
988 */
989int iscsi_tcp_task_init(struct iscsi_task *task)
990{
991 struct iscsi_tcp_task *tcp_task = task->dd_data;
992 struct iscsi_conn *conn = task->conn;
993 struct scsi_cmnd *sc = task->sc;
994 int err;
995
996 if (!sc) {
997 /*
998 * mgmt tasks do not have a scatterlist since they come
999 * in from the iscsi interface.
1000 */
1001 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
1002
1003 return conn->session->tt->init_pdu(task, 0, task->data_count);
1004 }
1005
1006 BUG_ON(kfifo_len(&tcp_task->r2tqueue));
1007 tcp_task->exp_datasn = 0;
1008
1009 /* Prepare PDU, optionally w/ immediate data */
1010 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
1011 task->itt, task->imm_count, task->unsol_r2t.data_length);
1012
1013 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
1014 if (err)
1015 return err;
1016 task->imm_count = 0;
1017 return 0;
1018}
1019EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
1020
1021static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
1022{
1023 struct iscsi_tcp_task *tcp_task = task->dd_data;
1024 struct iscsi_r2t_info *r2t = NULL;
1025
1026 if (iscsi_task_has_unsol_data(task))
1027 r2t = &task->unsol_r2t;
1028 else {
1029 spin_lock_bh(&tcp_task->queue2pool);
1030 if (tcp_task->r2t) {
1031 r2t = tcp_task->r2t;
1032 /* Continue with this R2T? */
1033 if (r2t->data_length <= r2t->sent) {
1034 ISCSI_DBG_TCP(task->conn,
1035 " done with r2t %p\n", r2t);
1036 kfifo_in(&tcp_task->r2tpool.queue,
1037 (void *)&tcp_task->r2t,
1038 sizeof(void *));
1039 tcp_task->r2t = r2t = NULL;
1040 }
1041 }
1042
1043 if (r2t == NULL) {
1044 if (kfifo_out(&tcp_task->r2tqueue,
1045 (void *)&tcp_task->r2t, sizeof(void *)) !=
1046 sizeof(void *))
1047 r2t = NULL;
1048 else
1049 r2t = tcp_task->r2t;
1050 }
1051 spin_unlock_bh(&tcp_task->queue2pool);
1052 }
1053
1054 return r2t;
1055}
1056
1057/**
1058 * iscsi_tcp_task_xmit - xmit normal PDU task
1059 * @task: iscsi command task
1060 *
1061 * We're expected to return 0 when everything was transmitted successfully,
1062 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1063 * of error.
1064 */
1065int iscsi_tcp_task_xmit(struct iscsi_task *task)
1066{
1067 struct iscsi_conn *conn = task->conn;
1068 struct iscsi_session *session = conn->session;
1069 struct iscsi_r2t_info *r2t;
1070 int rc = 0;
1071
1072flush:
1073 /* Flush any pending data first. */
1074 rc = session->tt->xmit_pdu(task);
1075 if (rc < 0)
1076 return rc;
1077
1078 /* mgmt command */
1079 if (!task->sc) {
1080 if (task->hdr->itt == RESERVED_ITT)
1081 iscsi_put_task(task);
1082 return 0;
1083 }
1084
1085 /* Are we done already? */
1086 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1087 return 0;
1088
1089 r2t = iscsi_tcp_get_curr_r2t(task);
1090 if (r2t == NULL) {
1091 /* Waiting for more R2Ts to arrive. */
1092 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1093 return 0;
1094 }
1095
1096 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1097 if (rc)
1098 return rc;
1099 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1100
1101 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1102 r2t, r2t->datasn - 1, task->hdr->itt,
1103 r2t->data_offset + r2t->sent, r2t->data_count);
1104
1105 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1106 r2t->data_count);
1107 if (rc) {
1108 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1109 return rc;
1110 }
1111
1112 r2t->sent += r2t->data_count;
1113 goto flush;
1114}
1115EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1116
1117struct iscsi_cls_conn *
1118iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1119 uint32_t conn_idx)
1120
1121{
1122 struct iscsi_conn *conn;
1123 struct iscsi_cls_conn *cls_conn;
1124 struct iscsi_tcp_conn *tcp_conn;
1125
1126 cls_conn = iscsi_conn_setup(cls_session,
1127 sizeof(*tcp_conn) + dd_data_size, conn_idx);
1128 if (!cls_conn)
1129 return NULL;
1130 conn = cls_conn->dd_data;
1131 /*
1132 * due to strange issues with iser these are not set
1133 * in iscsi_conn_setup
1134 */
1135 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1136
1137 tcp_conn = conn->dd_data;
1138 tcp_conn->iscsi_conn = conn;
1139 tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1140 return cls_conn;
1141}
1142EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1143
1144void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1145{
1146 iscsi_conn_teardown(cls_conn);
1147}
1148EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1149
1150int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1151{
1152 int i;
1153 int cmd_i;
1154
1155 /*
1156 * initialize per-task: R2T pool and xmit queue
1157 */
1158 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1159 struct iscsi_task *task = session->cmds[cmd_i];
1160 struct iscsi_tcp_task *tcp_task = task->dd_data;
1161
1162 /*
1163 * pre-allocated x2 as much r2ts to handle race when
1164 * target acks DataOut faster than we data_xmit() queues
1165 * could replenish r2tqueue.
1166 */
1167
1168 /* R2T pool */
1169 if (iscsi_pool_init(&tcp_task->r2tpool,
1170 session->max_r2t * 2, NULL,
1171 sizeof(struct iscsi_r2t_info))) {
1172 goto r2t_alloc_fail;
1173 }
1174
1175 /* R2T xmit queue */
1176 if (kfifo_alloc(&tcp_task->r2tqueue,
1177 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1178 iscsi_pool_free(&tcp_task->r2tpool);
1179 goto r2t_alloc_fail;
1180 }
1181 spin_lock_init(&tcp_task->pool2queue);
1182 spin_lock_init(&tcp_task->queue2pool);
1183 }
1184
1185 return 0;
1186
1187r2t_alloc_fail:
1188 for (i = 0; i < cmd_i; i++) {
1189 struct iscsi_task *task = session->cmds[i];
1190 struct iscsi_tcp_task *tcp_task = task->dd_data;
1191
1192 kfifo_free(&tcp_task->r2tqueue);
1193 iscsi_pool_free(&tcp_task->r2tpool);
1194 }
1195 return -ENOMEM;
1196}
1197EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1198
1199void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1200{
1201 int i;
1202
1203 for (i = 0; i < session->cmds_max; i++) {
1204 struct iscsi_task *task = session->cmds[i];
1205 struct iscsi_tcp_task *tcp_task = task->dd_data;
1206
1207 kfifo_free(&tcp_task->r2tqueue);
1208 iscsi_pool_free(&tcp_task->r2tpool);
1209 }
1210}
1211EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1212
1213int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1214{
1215 struct iscsi_session *session = conn->session;
1216 unsigned short r2ts = 0;
1217
1218 sscanf(buf, "%hu", &r2ts);
1219 if (session->max_r2t == r2ts)
1220 return 0;
1221
1222 if (!r2ts || !is_power_of_2(r2ts))
1223 return -EINVAL;
1224
1225 session->max_r2t = r2ts;
1226 iscsi_tcp_r2tpool_free(session);
1227 return iscsi_tcp_r2tpool_alloc(session);
1228}
1229EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1230
1231void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1232 struct iscsi_stats *stats)
1233{
1234 struct iscsi_conn *conn = cls_conn->dd_data;
1235
1236 stats->txdata_octets = conn->txdata_octets;
1237 stats->rxdata_octets = conn->rxdata_octets;
1238 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1239 stats->dataout_pdus = conn->dataout_pdus_cnt;
1240 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1241 stats->datain_pdus = conn->datain_pdus_cnt;
1242 stats->r2t_pdus = conn->r2t_pdus_cnt;
1243 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1244 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1245}
1246EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);