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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 <linux/types.h>
30#include <linux/list.h>
31#include <linux/inet.h>
32#include <linux/slab.h>
33#include <linux/file.h>
34#include <linux/blkdev.h>
35#include <linux/crypto.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 crypto_hash_update(segment->hash, &sg, copied);
218 }
219
220 segment->copied += copied;
221 if (segment->copied < segment->size) {
222 iscsi_tcp_segment_map(segment, recv);
223 return 0;
224 }
225
226 segment->total_copied += segment->copied;
227 segment->copied = 0;
228 segment->size = 0;
229
230 /* Unmap the current scatterlist page, if there is one. */
231 iscsi_tcp_segment_unmap(segment);
232
233 /* Do we have more scatterlist entries? */
234 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
235 segment->total_copied, segment->total_size);
236 if (segment->total_copied < segment->total_size) {
237 /* Proceed to the next entry in the scatterlist. */
238 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
239 0);
240 iscsi_tcp_segment_map(segment, recv);
241 BUG_ON(segment->size == 0);
242 return 0;
243 }
244
245 /* Do we need to handle padding? */
246 if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
247 pad = iscsi_padding(segment->total_copied);
248 if (pad != 0) {
249 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
250 "consume %d pad bytes\n", pad);
251 segment->total_size += pad;
252 segment->size = pad;
253 segment->data = segment->padbuf;
254 return 0;
255 }
256 }
257
258 /*
259 * Set us up for transferring the data digest. hdr digest
260 * is completely handled in hdr done function.
261 */
262 if (segment->hash) {
263 crypto_hash_final(segment->hash, segment->digest);
264 iscsi_tcp_segment_splice_digest(segment,
265 recv ? segment->recv_digest : segment->digest);
266 return 0;
267 }
268
269 return 1;
270}
271EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
272
273/**
274 * iscsi_tcp_segment_recv - copy data to segment
275 * @tcp_conn: the iSCSI TCP connection
276 * @segment: the buffer to copy to
277 * @ptr: data pointer
278 * @len: amount of data available
279 *
280 * This function copies up to @len bytes to the
281 * given buffer, and returns the number of bytes
282 * consumed, which can actually be less than @len.
283 *
284 * If hash digest is enabled, the function will update the
285 * hash while copying.
286 * Combining these two operations doesn't buy us a lot (yet),
287 * but in the future we could implement combined copy+crc,
288 * just way we do for network layer checksums.
289 */
290static int
291iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
292 struct iscsi_segment *segment, const void *ptr,
293 unsigned int len)
294{
295 unsigned int copy = 0, copied = 0;
296
297 while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
298 if (copied == len) {
299 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
300 "copied %d bytes\n", len);
301 break;
302 }
303
304 copy = min(len - copied, segment->size - segment->copied);
305 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
306 memcpy(segment->data + segment->copied, ptr + copied, copy);
307 copied += copy;
308 }
309 return copied;
310}
311
312inline void
313iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
314 unsigned char digest[ISCSI_DIGEST_SIZE])
315{
316 struct scatterlist sg;
317
318 sg_init_one(&sg, hdr, hdrlen);
319 crypto_hash_digest(hash, &sg, hdrlen, digest);
320}
321EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
322
323static inline int
324iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
325 struct iscsi_segment *segment)
326{
327 if (!segment->digest_len)
328 return 1;
329
330 if (memcmp(segment->recv_digest, segment->digest,
331 segment->digest_len)) {
332 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
333 return 0;
334 }
335
336 return 1;
337}
338
339/*
340 * Helper function to set up segment buffer
341 */
342static inline void
343__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
344 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
345{
346 memset(segment, 0, sizeof(*segment));
347 segment->total_size = size;
348 segment->done = done;
349
350 if (hash) {
351 segment->hash = hash;
352 crypto_hash_init(hash);
353 }
354}
355
356inline void
357iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
358 size_t size, iscsi_segment_done_fn_t *done,
359 struct hash_desc *hash)
360{
361 __iscsi_segment_init(segment, size, done, hash);
362 segment->data = data;
363 segment->size = size;
364}
365EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
366
367inline int
368iscsi_segment_seek_sg(struct iscsi_segment *segment,
369 struct scatterlist *sg_list, unsigned int sg_count,
370 unsigned int offset, size_t size,
371 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
372{
373 struct scatterlist *sg;
374 unsigned int i;
375
376 __iscsi_segment_init(segment, size, done, hash);
377 for_each_sg(sg_list, sg, sg_count, i) {
378 if (offset < sg->length) {
379 iscsi_tcp_segment_init_sg(segment, sg, offset);
380 return 0;
381 }
382 offset -= sg->length;
383 }
384
385 return ISCSI_ERR_DATA_OFFSET;
386}
387EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
388
389/**
390 * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
391 * @tcp_conn: iscsi connection to prep for
392 *
393 * This function always passes NULL for the hash argument, because when this
394 * function is called we do not yet know the final size of the header and want
395 * to delay the digest processing until we know that.
396 */
397void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
398{
399 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
400 "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
401 "digest enabled" : "digest disabled");
402 iscsi_segment_init_linear(&tcp_conn->in.segment,
403 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
404 iscsi_tcp_hdr_recv_done, NULL);
405}
406EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
407
408/*
409 * Handle incoming reply to any other type of command
410 */
411static int
412iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
413 struct iscsi_segment *segment)
414{
415 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
416 int rc = 0;
417
418 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
419 return ISCSI_ERR_DATA_DGST;
420
421 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
422 conn->data, tcp_conn->in.datalen);
423 if (rc)
424 return rc;
425
426 iscsi_tcp_hdr_recv_prep(tcp_conn);
427 return 0;
428}
429
430static void
431iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
432{
433 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
434 struct hash_desc *rx_hash = NULL;
435
436 if (conn->datadgst_en &&
437 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
438 rx_hash = tcp_conn->rx_hash;
439
440 iscsi_segment_init_linear(&tcp_conn->in.segment,
441 conn->data, tcp_conn->in.datalen,
442 iscsi_tcp_data_recv_done, rx_hash);
443}
444
445/**
446 * iscsi_tcp_cleanup_task - free tcp_task resources
447 * @task: iscsi task
448 *
449 * must be called with session back_lock
450 */
451void iscsi_tcp_cleanup_task(struct iscsi_task *task)
452{
453 struct iscsi_tcp_task *tcp_task = task->dd_data;
454 struct iscsi_r2t_info *r2t;
455
456 /* nothing to do for mgmt */
457 if (!task->sc)
458 return;
459
460 spin_lock_bh(&tcp_task->queue2pool);
461 /* flush task's r2t queues */
462 while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
463 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
464 sizeof(void*));
465 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
466 }
467
468 r2t = tcp_task->r2t;
469 if (r2t != NULL) {
470 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
471 sizeof(void*));
472 tcp_task->r2t = NULL;
473 }
474 spin_unlock_bh(&tcp_task->queue2pool);
475}
476EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
477
478/**
479 * iscsi_tcp_data_in - SCSI Data-In Response processing
480 * @conn: iscsi connection
481 * @task: scsi command task
482 */
483static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
484{
485 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
486 struct iscsi_tcp_task *tcp_task = task->dd_data;
487 struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
488 int datasn = be32_to_cpu(rhdr->datasn);
489 unsigned total_in_length = scsi_in(task->sc)->length;
490
491 /*
492 * lib iscsi will update this in the completion handling if there
493 * is status.
494 */
495 if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
496 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
497
498 if (tcp_conn->in.datalen == 0)
499 return 0;
500
501 if (tcp_task->exp_datasn != datasn) {
502 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
503 "\n", tcp_task->exp_datasn, datasn);
504 return ISCSI_ERR_DATASN;
505 }
506
507 tcp_task->exp_datasn++;
508
509 tcp_task->data_offset = be32_to_cpu(rhdr->offset);
510 if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
511 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
512 "total_length_in(%d)\n", tcp_task->data_offset,
513 tcp_conn->in.datalen, total_in_length);
514 return ISCSI_ERR_DATA_OFFSET;
515 }
516
517 conn->datain_pdus_cnt++;
518 return 0;
519}
520
521/**
522 * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
523 * @conn: iscsi connection
524 * @task: scsi command task
525 */
526static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
527{
528 struct iscsi_session *session = conn->session;
529 struct iscsi_tcp_task *tcp_task = task->dd_data;
530 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
531 struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
532 struct iscsi_r2t_info *r2t;
533 int r2tsn = be32_to_cpu(rhdr->r2tsn);
534 u32 data_length;
535 u32 data_offset;
536 int rc;
537
538 if (tcp_conn->in.datalen) {
539 iscsi_conn_printk(KERN_ERR, conn,
540 "invalid R2t with datalen %d\n",
541 tcp_conn->in.datalen);
542 return ISCSI_ERR_DATALEN;
543 }
544
545 if (tcp_task->exp_datasn != r2tsn){
546 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
547 tcp_task->exp_datasn, r2tsn);
548 return ISCSI_ERR_R2TSN;
549 }
550
551 /* fill-in new R2T associated with the task */
552 iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
553
554 if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
555 iscsi_conn_printk(KERN_INFO, conn,
556 "dropping R2T itt %d in recovery.\n",
557 task->itt);
558 return 0;
559 }
560
561 data_length = be32_to_cpu(rhdr->data_length);
562 if (data_length == 0) {
563 iscsi_conn_printk(KERN_ERR, conn,
564 "invalid R2T with zero data len\n");
565 return ISCSI_ERR_DATALEN;
566 }
567
568 if (data_length > session->max_burst)
569 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
570 "burst %u. Attempting to execute request.\n",
571 data_length, session->max_burst);
572
573 data_offset = be32_to_cpu(rhdr->data_offset);
574 if (data_offset + data_length > scsi_out(task->sc)->length) {
575 iscsi_conn_printk(KERN_ERR, conn,
576 "invalid R2T with data len %u at offset %u "
577 "and total length %d\n", data_length,
578 data_offset, scsi_out(task->sc)->length);
579 return ISCSI_ERR_DATALEN;
580 }
581
582 spin_lock(&tcp_task->pool2queue);
583 rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
584 if (!rc) {
585 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
586 "Target has sent more R2Ts than it "
587 "negotiated for or driver has leaked.\n");
588 spin_unlock(&tcp_task->pool2queue);
589 return ISCSI_ERR_PROTO;
590 }
591
592 r2t->exp_statsn = rhdr->statsn;
593 r2t->data_length = data_length;
594 r2t->data_offset = data_offset;
595
596 r2t->ttt = rhdr->ttt; /* no flip */
597 r2t->datasn = 0;
598 r2t->sent = 0;
599
600 tcp_task->exp_datasn = r2tsn + 1;
601 kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
602 conn->r2t_pdus_cnt++;
603 spin_unlock(&tcp_task->pool2queue);
604
605 iscsi_requeue_task(task);
606 return 0;
607}
608
609/*
610 * Handle incoming reply to DataIn command
611 */
612static int
613iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
614 struct iscsi_segment *segment)
615{
616 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
617 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
618 int rc;
619
620 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
621 return ISCSI_ERR_DATA_DGST;
622
623 /* check for non-exceptional status */
624 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
625 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
626 if (rc)
627 return rc;
628 }
629
630 iscsi_tcp_hdr_recv_prep(tcp_conn);
631 return 0;
632}
633
634/**
635 * iscsi_tcp_hdr_dissect - process PDU header
636 * @conn: iSCSI connection
637 * @hdr: PDU header
638 *
639 * This function analyzes the header of the PDU received,
640 * and performs several sanity checks. If the PDU is accompanied
641 * by data, the receive buffer is set up to copy the incoming data
642 * to the correct location.
643 */
644static int
645iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
646{
647 int rc = 0, opcode, ahslen;
648 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
649 struct iscsi_task *task;
650
651 /* verify PDU length */
652 tcp_conn->in.datalen = ntoh24(hdr->dlength);
653 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
654 iscsi_conn_printk(KERN_ERR, conn,
655 "iscsi_tcp: datalen %d > %d\n",
656 tcp_conn->in.datalen, conn->max_recv_dlength);
657 return ISCSI_ERR_DATALEN;
658 }
659
660 /* Additional header segments. So far, we don't
661 * process additional headers.
662 */
663 ahslen = hdr->hlength << 2;
664
665 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
666 /* verify itt (itt encoding: age+cid+itt) */
667 rc = iscsi_verify_itt(conn, hdr->itt);
668 if (rc)
669 return rc;
670
671 ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
672 opcode, ahslen, tcp_conn->in.datalen);
673
674 switch(opcode) {
675 case ISCSI_OP_SCSI_DATA_IN:
676 spin_lock(&conn->session->back_lock);
677 task = iscsi_itt_to_ctask(conn, hdr->itt);
678 if (!task)
679 rc = ISCSI_ERR_BAD_ITT;
680 else
681 rc = iscsi_tcp_data_in(conn, task);
682 if (rc) {
683 spin_unlock(&conn->session->back_lock);
684 break;
685 }
686
687 if (tcp_conn->in.datalen) {
688 struct iscsi_tcp_task *tcp_task = task->dd_data;
689 struct hash_desc *rx_hash = NULL;
690 struct scsi_data_buffer *sdb = scsi_in(task->sc);
691
692 /*
693 * Setup copy of Data-In into the Scsi_Cmnd
694 * Scatterlist case:
695 * We set up the iscsi_segment to point to the next
696 * scatterlist entry to copy to. As we go along,
697 * we move on to the next scatterlist entry and
698 * update the digest per-entry.
699 */
700 if (conn->datadgst_en &&
701 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
702 rx_hash = tcp_conn->rx_hash;
703
704 ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
705 "offset=%d, datalen=%d)\n",
706 tcp_task->data_offset,
707 tcp_conn->in.datalen);
708 task->last_xfer = jiffies;
709 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
710 sdb->table.sgl,
711 sdb->table.nents,
712 tcp_task->data_offset,
713 tcp_conn->in.datalen,
714 iscsi_tcp_process_data_in,
715 rx_hash);
716 spin_unlock(&conn->session->back_lock);
717 return rc;
718 }
719 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
720 spin_unlock(&conn->session->back_lock);
721 break;
722 case ISCSI_OP_SCSI_CMD_RSP:
723 if (tcp_conn->in.datalen) {
724 iscsi_tcp_data_recv_prep(tcp_conn);
725 return 0;
726 }
727 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
728 break;
729 case ISCSI_OP_R2T:
730 spin_lock(&conn->session->back_lock);
731 task = iscsi_itt_to_ctask(conn, hdr->itt);
732 spin_unlock(&conn->session->back_lock);
733 if (!task)
734 rc = ISCSI_ERR_BAD_ITT;
735 else if (ahslen)
736 rc = ISCSI_ERR_AHSLEN;
737 else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
738 task->last_xfer = jiffies;
739 spin_lock(&conn->session->frwd_lock);
740 rc = iscsi_tcp_r2t_rsp(conn, task);
741 spin_unlock(&conn->session->frwd_lock);
742 } else
743 rc = ISCSI_ERR_PROTO;
744 break;
745 case ISCSI_OP_LOGIN_RSP:
746 case ISCSI_OP_TEXT_RSP:
747 case ISCSI_OP_REJECT:
748 case ISCSI_OP_ASYNC_EVENT:
749 /*
750 * It is possible that we could get a PDU with a buffer larger
751 * than 8K, but there are no targets that currently do this.
752 * For now we fail until we find a vendor that needs it
753 */
754 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
755 iscsi_conn_printk(KERN_ERR, conn,
756 "iscsi_tcp: received buffer of "
757 "len %u but conn buffer is only %u "
758 "(opcode %0x)\n",
759 tcp_conn->in.datalen,
760 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
761 rc = ISCSI_ERR_PROTO;
762 break;
763 }
764
765 /* If there's data coming in with the response,
766 * receive it to the connection's buffer.
767 */
768 if (tcp_conn->in.datalen) {
769 iscsi_tcp_data_recv_prep(tcp_conn);
770 return 0;
771 }
772 /* fall through */
773 case ISCSI_OP_LOGOUT_RSP:
774 case ISCSI_OP_NOOP_IN:
775 case ISCSI_OP_SCSI_TMFUNC_RSP:
776 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
777 break;
778 default:
779 rc = ISCSI_ERR_BAD_OPCODE;
780 break;
781 }
782
783 if (rc == 0) {
784 /* Anything that comes with data should have
785 * been handled above. */
786 if (tcp_conn->in.datalen)
787 return ISCSI_ERR_PROTO;
788 iscsi_tcp_hdr_recv_prep(tcp_conn);
789 }
790
791 return rc;
792}
793
794/**
795 * iscsi_tcp_hdr_recv_done - process PDU header
796 *
797 * This is the callback invoked when the PDU header has
798 * been received. If the header is followed by additional
799 * header segments, we go back for more data.
800 */
801static int
802iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
803 struct iscsi_segment *segment)
804{
805 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
806 struct iscsi_hdr *hdr;
807
808 /* Check if there are additional header segments
809 * *prior* to computing the digest, because we
810 * may need to go back to the caller for more.
811 */
812 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
813 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
814 /* Bump the header length - the caller will
815 * just loop around and get the AHS for us, and
816 * call again. */
817 unsigned int ahslen = hdr->hlength << 2;
818
819 /* Make sure we don't overflow */
820 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
821 return ISCSI_ERR_AHSLEN;
822
823 segment->total_size += ahslen;
824 segment->size += ahslen;
825 return 0;
826 }
827
828 /* We're done processing the header. See if we're doing
829 * header digests; if so, set up the recv_digest buffer
830 * and go back for more. */
831 if (conn->hdrdgst_en &&
832 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
833 if (segment->digest_len == 0) {
834 /*
835 * Even if we offload the digest processing we
836 * splice it in so we can increment the skb/segment
837 * counters in preparation for the data segment.
838 */
839 iscsi_tcp_segment_splice_digest(segment,
840 segment->recv_digest);
841 return 0;
842 }
843
844 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
845 segment->total_copied - ISCSI_DIGEST_SIZE,
846 segment->digest);
847
848 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
849 return ISCSI_ERR_HDR_DGST;
850 }
851
852 tcp_conn->in.hdr = hdr;
853 return iscsi_tcp_hdr_dissect(conn, hdr);
854}
855
856/**
857 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
858 * @tcp_conn: iscsi tcp conn
859 *
860 * returns non zero if we are currently processing or setup to process
861 * a header.
862 */
863inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
864{
865 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
866}
867EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
868
869/**
870 * iscsi_tcp_recv_skb - Process skb
871 * @conn: iscsi connection
872 * @skb: network buffer with header and/or data segment
873 * @offset: offset in skb
874 * @offload: bool indicating if transfer was offloaded
875 *
876 * Will return status of transfer in status. And will return
877 * number of bytes copied.
878 */
879int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
880 unsigned int offset, bool offloaded, int *status)
881{
882 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
883 struct iscsi_segment *segment = &tcp_conn->in.segment;
884 struct skb_seq_state seq;
885 unsigned int consumed = 0;
886 int rc = 0;
887
888 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
889 /*
890 * Update for each skb instead of pdu, because over slow networks a
891 * data_in's data could take a while to read in. We also want to
892 * account for r2ts.
893 */
894 conn->last_recv = jiffies;
895
896 if (unlikely(conn->suspend_rx)) {
897 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
898 *status = ISCSI_TCP_SUSPENDED;
899 return 0;
900 }
901
902 if (offloaded) {
903 segment->total_copied = segment->total_size;
904 goto segment_done;
905 }
906
907 skb_prepare_seq_read(skb, offset, skb->len, &seq);
908 while (1) {
909 unsigned int avail;
910 const u8 *ptr;
911
912 avail = skb_seq_read(consumed, &ptr, &seq);
913 if (avail == 0) {
914 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
915 consumed);
916 *status = ISCSI_TCP_SKB_DONE;
917 goto skb_done;
918 }
919 BUG_ON(segment->copied >= segment->size);
920
921 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
922 avail);
923 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
924 BUG_ON(rc == 0);
925 consumed += rc;
926
927 if (segment->total_copied >= segment->total_size) {
928 skb_abort_seq_read(&seq);
929 goto segment_done;
930 }
931 }
932
933segment_done:
934 *status = ISCSI_TCP_SEGMENT_DONE;
935 ISCSI_DBG_TCP(conn, "segment done\n");
936 rc = segment->done(tcp_conn, segment);
937 if (rc != 0) {
938 *status = ISCSI_TCP_CONN_ERR;
939 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
940 iscsi_conn_failure(conn, rc);
941 return 0;
942 }
943 /* The done() functions sets up the next segment. */
944
945skb_done:
946 conn->rxdata_octets += consumed;
947 return consumed;
948}
949EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
950
951/**
952 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
953 * @conn: iscsi connection
954 * @task: scsi command task
955 * @sc: scsi command
956 */
957int iscsi_tcp_task_init(struct iscsi_task *task)
958{
959 struct iscsi_tcp_task *tcp_task = task->dd_data;
960 struct iscsi_conn *conn = task->conn;
961 struct scsi_cmnd *sc = task->sc;
962 int err;
963
964 if (!sc) {
965 /*
966 * mgmt tasks do not have a scatterlist since they come
967 * in from the iscsi interface.
968 */
969 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
970
971 return conn->session->tt->init_pdu(task, 0, task->data_count);
972 }
973
974 BUG_ON(kfifo_len(&tcp_task->r2tqueue));
975 tcp_task->exp_datasn = 0;
976
977 /* Prepare PDU, optionally w/ immediate data */
978 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
979 task->itt, task->imm_count, task->unsol_r2t.data_length);
980
981 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
982 if (err)
983 return err;
984 task->imm_count = 0;
985 return 0;
986}
987EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
988
989static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
990{
991 struct iscsi_tcp_task *tcp_task = task->dd_data;
992 struct iscsi_r2t_info *r2t = NULL;
993
994 if (iscsi_task_has_unsol_data(task))
995 r2t = &task->unsol_r2t;
996 else {
997 spin_lock_bh(&tcp_task->queue2pool);
998 if (tcp_task->r2t) {
999 r2t = tcp_task->r2t;
1000 /* Continue with this R2T? */
1001 if (r2t->data_length <= r2t->sent) {
1002 ISCSI_DBG_TCP(task->conn,
1003 " done with r2t %p\n", r2t);
1004 kfifo_in(&tcp_task->r2tpool.queue,
1005 (void *)&tcp_task->r2t,
1006 sizeof(void *));
1007 tcp_task->r2t = r2t = NULL;
1008 }
1009 }
1010
1011 if (r2t == NULL) {
1012 if (kfifo_out(&tcp_task->r2tqueue,
1013 (void *)&tcp_task->r2t, sizeof(void *)) !=
1014 sizeof(void *))
1015 r2t = NULL;
1016 else
1017 r2t = tcp_task->r2t;
1018 }
1019 spin_unlock_bh(&tcp_task->queue2pool);
1020 }
1021
1022 return r2t;
1023}
1024
1025/**
1026 * iscsi_tcp_task_xmit - xmit normal PDU task
1027 * @task: iscsi command task
1028 *
1029 * We're expected to return 0 when everything was transmitted successfully,
1030 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1031 * of error.
1032 */
1033int iscsi_tcp_task_xmit(struct iscsi_task *task)
1034{
1035 struct iscsi_conn *conn = task->conn;
1036 struct iscsi_session *session = conn->session;
1037 struct iscsi_r2t_info *r2t;
1038 int rc = 0;
1039
1040flush:
1041 /* Flush any pending data first. */
1042 rc = session->tt->xmit_pdu(task);
1043 if (rc < 0)
1044 return rc;
1045
1046 /* mgmt command */
1047 if (!task->sc) {
1048 if (task->hdr->itt == RESERVED_ITT)
1049 iscsi_put_task(task);
1050 return 0;
1051 }
1052
1053 /* Are we done already? */
1054 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1055 return 0;
1056
1057 r2t = iscsi_tcp_get_curr_r2t(task);
1058 if (r2t == NULL) {
1059 /* Waiting for more R2Ts to arrive. */
1060 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1061 return 0;
1062 }
1063
1064 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1065 if (rc)
1066 return rc;
1067 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1068
1069 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1070 r2t, r2t->datasn - 1, task->hdr->itt,
1071 r2t->data_offset + r2t->sent, r2t->data_count);
1072
1073 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1074 r2t->data_count);
1075 if (rc) {
1076 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1077 return rc;
1078 }
1079
1080 r2t->sent += r2t->data_count;
1081 goto flush;
1082}
1083EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1084
1085struct iscsi_cls_conn *
1086iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1087 uint32_t conn_idx)
1088
1089{
1090 struct iscsi_conn *conn;
1091 struct iscsi_cls_conn *cls_conn;
1092 struct iscsi_tcp_conn *tcp_conn;
1093
1094 cls_conn = iscsi_conn_setup(cls_session,
1095 sizeof(*tcp_conn) + dd_data_size, conn_idx);
1096 if (!cls_conn)
1097 return NULL;
1098 conn = cls_conn->dd_data;
1099 /*
1100 * due to strange issues with iser these are not set
1101 * in iscsi_conn_setup
1102 */
1103 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1104
1105 tcp_conn = conn->dd_data;
1106 tcp_conn->iscsi_conn = conn;
1107 tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1108 return cls_conn;
1109}
1110EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1111
1112void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1113{
1114 iscsi_conn_teardown(cls_conn);
1115}
1116EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1117
1118int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1119{
1120 int i;
1121 int cmd_i;
1122
1123 /*
1124 * initialize per-task: R2T pool and xmit queue
1125 */
1126 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1127 struct iscsi_task *task = session->cmds[cmd_i];
1128 struct iscsi_tcp_task *tcp_task = task->dd_data;
1129
1130 /*
1131 * pre-allocated x2 as much r2ts to handle race when
1132 * target acks DataOut faster than we data_xmit() queues
1133 * could replenish r2tqueue.
1134 */
1135
1136 /* R2T pool */
1137 if (iscsi_pool_init(&tcp_task->r2tpool,
1138 session->max_r2t * 2, NULL,
1139 sizeof(struct iscsi_r2t_info))) {
1140 goto r2t_alloc_fail;
1141 }
1142
1143 /* R2T xmit queue */
1144 if (kfifo_alloc(&tcp_task->r2tqueue,
1145 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1146 iscsi_pool_free(&tcp_task->r2tpool);
1147 goto r2t_alloc_fail;
1148 }
1149 spin_lock_init(&tcp_task->pool2queue);
1150 spin_lock_init(&tcp_task->queue2pool);
1151 }
1152
1153 return 0;
1154
1155r2t_alloc_fail:
1156 for (i = 0; i < cmd_i; i++) {
1157 struct iscsi_task *task = session->cmds[i];
1158 struct iscsi_tcp_task *tcp_task = task->dd_data;
1159
1160 kfifo_free(&tcp_task->r2tqueue);
1161 iscsi_pool_free(&tcp_task->r2tpool);
1162 }
1163 return -ENOMEM;
1164}
1165EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1166
1167void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1168{
1169 int i;
1170
1171 for (i = 0; i < session->cmds_max; i++) {
1172 struct iscsi_task *task = session->cmds[i];
1173 struct iscsi_tcp_task *tcp_task = task->dd_data;
1174
1175 kfifo_free(&tcp_task->r2tqueue);
1176 iscsi_pool_free(&tcp_task->r2tpool);
1177 }
1178}
1179EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1180
1181int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf)
1182{
1183 struct iscsi_session *session = conn->session;
1184 unsigned short r2ts = 0;
1185
1186 sscanf(buf, "%hu", &r2ts);
1187 if (session->max_r2t == r2ts)
1188 return 0;
1189
1190 if (!r2ts || !is_power_of_2(r2ts))
1191 return -EINVAL;
1192
1193 session->max_r2t = r2ts;
1194 iscsi_tcp_r2tpool_free(session);
1195 return iscsi_tcp_r2tpool_alloc(session);
1196}
1197EXPORT_SYMBOL_GPL(iscsi_tcp_set_max_r2t);
1198
1199void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1200 struct iscsi_stats *stats)
1201{
1202 struct iscsi_conn *conn = cls_conn->dd_data;
1203
1204 stats->txdata_octets = conn->txdata_octets;
1205 stats->rxdata_octets = conn->rxdata_octets;
1206 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1207 stats->dataout_pdus = conn->dataout_pdus_cnt;
1208 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1209 stats->datain_pdus = conn->datain_pdus_cnt;
1210 stats->r2t_pdus = conn->r2t_pdus_cnt;
1211 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1212 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1213}
1214EXPORT_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 *
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);