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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 <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 <net/tcp.h>
40#include <scsi/scsi_cmnd.h>
41#include <scsi/scsi_device.h>
42#include <scsi/scsi_host.h>
43#include <scsi/scsi.h>
44#include <scsi/scsi_transport_iscsi.h>
45
46#include "iscsi_tcp.h"
47
48MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
49 "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
50 "Alex Aizman <itn780@yahoo.com>");
51MODULE_DESCRIPTION("iSCSI/TCP data-path");
52MODULE_LICENSE("GPL");
53
54static int iscsi_dbg_libtcp;
55module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
56 S_IRUGO | S_IWUSR);
57MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
58 "module. Set to 1 to turn on, and zero to turn off. Default "
59 "is off.");
60
61#define ISCSI_DBG_TCP(_conn, dbg_fmt, arg...) \
62 do { \
63 if (iscsi_dbg_libtcp) \
64 iscsi_conn_printk(KERN_INFO, _conn, \
65 "%s " dbg_fmt, \
66 __func__, ##arg); \
67 } while (0);
68
69static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
70 struct iscsi_segment *segment);
71
72/*
73 * Scatterlist handling: inside the iscsi_segment, we
74 * remember an index into the scatterlist, and set data/size
75 * to the current scatterlist entry. For highmem pages, we
76 * kmap as needed.
77 *
78 * Note that the page is unmapped when we return from
79 * TCP's data_ready handler, so we may end up mapping and
80 * unmapping the same page repeatedly. The whole reason
81 * for this is that we shouldn't keep the page mapped
82 * outside the softirq.
83 */
84
85/**
86 * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
87 * @segment: the buffer object
88 * @sg: scatterlist
89 * @offset: byte offset into that sg entry
90 *
91 * This function sets up the segment so that subsequent
92 * data is copied to the indicated sg entry, at the given
93 * offset.
94 */
95static inline void
96iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
97 struct scatterlist *sg, unsigned int offset)
98{
99 segment->sg = sg;
100 segment->sg_offset = offset;
101 segment->size = min(sg->length - offset,
102 segment->total_size - segment->total_copied);
103 segment->data = NULL;
104}
105
106/**
107 * iscsi_tcp_segment_map - map the current S/G page
108 * @segment: iscsi_segment
109 * @recv: 1 if called from recv path
110 *
111 * We only need to possibly kmap data if scatter lists are being used,
112 * because the iscsi passthrough and internal IO paths will never use high
113 * mem pages.
114 */
115static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
116{
117 struct scatterlist *sg;
118
119 if (segment->data != NULL || !segment->sg)
120 return;
121
122 sg = segment->sg;
123 BUG_ON(segment->sg_mapped);
124 BUG_ON(sg->length == 0);
125
126 /*
127 * If the page count is greater than one it is ok to send
128 * to the network layer's zero copy send path. If not we
129 * have to go the slow sendmsg path. We always map for the
130 * recv path.
131 */
132 if (page_count(sg_page(sg)) >= 1 && !recv)
133 return;
134
135 if (recv) {
136 segment->atomic_mapped = true;
137 segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
138 } else {
139 segment->atomic_mapped = false;
140 /* the xmit path can sleep with the page mapped so use kmap */
141 segment->sg_mapped = kmap(sg_page(sg));
142 }
143
144 segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
145}
146
147void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
148{
149 if (segment->sg_mapped) {
150 if (segment->atomic_mapped)
151 kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
152 else
153 kunmap(sg_page(segment->sg));
154 segment->sg_mapped = NULL;
155 segment->data = NULL;
156 }
157}
158EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
159
160/*
161 * Splice the digest buffer into the buffer
162 */
163static inline void
164iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
165{
166 segment->data = digest;
167 segment->digest_len = ISCSI_DIGEST_SIZE;
168 segment->total_size += ISCSI_DIGEST_SIZE;
169 segment->size = ISCSI_DIGEST_SIZE;
170 segment->copied = 0;
171 segment->sg = NULL;
172 segment->hash = NULL;
173}
174
175/**
176 * iscsi_tcp_segment_done - check whether the segment is complete
177 * @tcp_conn: iscsi tcp connection
178 * @segment: iscsi segment to check
179 * @recv: set to one of this is called from the recv path
180 * @copied: number of bytes copied
181 *
182 * Check if we're done receiving this segment. If the receive
183 * buffer is full but we expect more data, move on to the
184 * next entry in the scatterlist.
185 *
186 * If the amount of data we received isn't a multiple of 4,
187 * we will transparently receive the pad bytes, too.
188 *
189 * This function must be re-entrant.
190 */
191int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
192 struct iscsi_segment *segment, int recv,
193 unsigned copied)
194{
195 struct scatterlist sg;
196 unsigned int pad;
197
198 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
199 segment->copied, copied, segment->size,
200 recv ? "recv" : "xmit");
201 if (segment->hash && copied) {
202 /*
203 * If a segment is kmapd we must unmap it before sending
204 * to the crypto layer since that will try to kmap it again.
205 */
206 iscsi_tcp_segment_unmap(segment);
207
208 if (!segment->data) {
209 sg_init_table(&sg, 1);
210 sg_set_page(&sg, sg_page(segment->sg), copied,
211 segment->copied + segment->sg_offset +
212 segment->sg->offset);
213 } else
214 sg_init_one(&sg, segment->data + segment->copied,
215 copied);
216 crypto_hash_update(segment->hash, &sg, copied);
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 crypto_hash_final(segment->hash, segment->digest);
263 iscsi_tcp_segment_splice_digest(segment,
264 recv ? segment->recv_digest : segment->digest);
265 return 0;
266 }
267
268 return 1;
269}
270EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
271
272/**
273 * iscsi_tcp_segment_recv - copy data to segment
274 * @tcp_conn: the iSCSI TCP connection
275 * @segment: the buffer to copy to
276 * @ptr: data pointer
277 * @len: amount of data available
278 *
279 * This function copies up to @len bytes to the
280 * given buffer, and returns the number of bytes
281 * consumed, which can actually be less than @len.
282 *
283 * If hash digest is enabled, the function will update the
284 * hash while copying.
285 * Combining these two operations doesn't buy us a lot (yet),
286 * but in the future we could implement combined copy+crc,
287 * just way we do for network layer checksums.
288 */
289static int
290iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
291 struct iscsi_segment *segment, const void *ptr,
292 unsigned int len)
293{
294 unsigned int copy = 0, copied = 0;
295
296 while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
297 if (copied == len) {
298 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
299 "copied %d bytes\n", len);
300 break;
301 }
302
303 copy = min(len - copied, segment->size - segment->copied);
304 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
305 memcpy(segment->data + segment->copied, ptr + copied, copy);
306 copied += copy;
307 }
308 return copied;
309}
310
311inline void
312iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
313 unsigned char digest[ISCSI_DIGEST_SIZE])
314{
315 struct scatterlist sg;
316
317 sg_init_one(&sg, hdr, hdrlen);
318 crypto_hash_digest(hash, &sg, hdrlen, digest);
319}
320EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
321
322static inline int
323iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
324 struct iscsi_segment *segment)
325{
326 if (!segment->digest_len)
327 return 1;
328
329 if (memcmp(segment->recv_digest, segment->digest,
330 segment->digest_len)) {
331 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
332 return 0;
333 }
334
335 return 1;
336}
337
338/*
339 * Helper function to set up segment buffer
340 */
341static inline void
342__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
343 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
344{
345 memset(segment, 0, sizeof(*segment));
346 segment->total_size = size;
347 segment->done = done;
348
349 if (hash) {
350 segment->hash = hash;
351 crypto_hash_init(hash);
352 }
353}
354
355inline void
356iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
357 size_t size, iscsi_segment_done_fn_t *done,
358 struct hash_desc *hash)
359{
360 __iscsi_segment_init(segment, size, done, hash);
361 segment->data = data;
362 segment->size = size;
363}
364EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
365
366inline int
367iscsi_segment_seek_sg(struct iscsi_segment *segment,
368 struct scatterlist *sg_list, unsigned int sg_count,
369 unsigned int offset, size_t size,
370 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
371{
372 struct scatterlist *sg;
373 unsigned int i;
374
375 __iscsi_segment_init(segment, size, done, hash);
376 for_each_sg(sg_list, sg, sg_count, i) {
377 if (offset < sg->length) {
378 iscsi_tcp_segment_init_sg(segment, sg, offset);
379 return 0;
380 }
381 offset -= sg->length;
382 }
383
384 return ISCSI_ERR_DATA_OFFSET;
385}
386EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
387
388/**
389 * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
390 * @tcp_conn: iscsi connection to prep for
391 *
392 * This function always passes NULL for the hash argument, because when this
393 * function is called we do not yet know the final size of the header and want
394 * to delay the digest processing until we know that.
395 */
396void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
397{
398 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
399 "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
400 "digest enabled" : "digest disabled");
401 iscsi_segment_init_linear(&tcp_conn->in.segment,
402 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
403 iscsi_tcp_hdr_recv_done, NULL);
404}
405EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
406
407/*
408 * Handle incoming reply to any other type of command
409 */
410static int
411iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
412 struct iscsi_segment *segment)
413{
414 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
415 int rc = 0;
416
417 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
418 return ISCSI_ERR_DATA_DGST;
419
420 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
421 conn->data, tcp_conn->in.datalen);
422 if (rc)
423 return rc;
424
425 iscsi_tcp_hdr_recv_prep(tcp_conn);
426 return 0;
427}
428
429static void
430iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
431{
432 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
433 struct hash_desc *rx_hash = NULL;
434
435 if (conn->datadgst_en &&
436 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
437 rx_hash = tcp_conn->rx_hash;
438
439 iscsi_segment_init_linear(&tcp_conn->in.segment,
440 conn->data, tcp_conn->in.datalen,
441 iscsi_tcp_data_recv_done, rx_hash);
442}
443
444/**
445 * iscsi_tcp_cleanup_task - free tcp_task resources
446 * @task: iscsi task
447 *
448 * must be called with session lock
449 */
450void iscsi_tcp_cleanup_task(struct iscsi_task *task)
451{
452 struct iscsi_tcp_task *tcp_task = task->dd_data;
453 struct iscsi_r2t_info *r2t;
454
455 /* nothing to do for mgmt */
456 if (!task->sc)
457 return;
458
459 /* flush task's r2t queues */
460 while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
461 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
462 sizeof(void*));
463 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
464 }
465
466 r2t = tcp_task->r2t;
467 if (r2t != NULL) {
468 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
469 sizeof(void*));
470 tcp_task->r2t = NULL;
471 }
472}
473EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
474
475/**
476 * iscsi_tcp_data_in - SCSI Data-In Response processing
477 * @conn: iscsi connection
478 * @task: scsi command task
479 */
480static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
481{
482 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
483 struct iscsi_tcp_task *tcp_task = task->dd_data;
484 struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
485 int datasn = be32_to_cpu(rhdr->datasn);
486 unsigned total_in_length = scsi_in(task->sc)->length;
487
488 /*
489 * lib iscsi will update this in the completion handling if there
490 * is status.
491 */
492 if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
493 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
494
495 if (tcp_conn->in.datalen == 0)
496 return 0;
497
498 if (tcp_task->exp_datasn != datasn) {
499 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
500 "\n", tcp_task->exp_datasn, datasn);
501 return ISCSI_ERR_DATASN;
502 }
503
504 tcp_task->exp_datasn++;
505
506 tcp_task->data_offset = be32_to_cpu(rhdr->offset);
507 if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
508 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
509 "total_length_in(%d)\n", tcp_task->data_offset,
510 tcp_conn->in.datalen, total_in_length);
511 return ISCSI_ERR_DATA_OFFSET;
512 }
513
514 conn->datain_pdus_cnt++;
515 return 0;
516}
517
518/**
519 * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
520 * @conn: iscsi connection
521 * @task: scsi command task
522 */
523static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
524{
525 struct iscsi_session *session = conn->session;
526 struct iscsi_tcp_task *tcp_task = task->dd_data;
527 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
528 struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
529 struct iscsi_r2t_info *r2t;
530 int r2tsn = be32_to_cpu(rhdr->r2tsn);
531 int rc;
532
533 if (tcp_conn->in.datalen) {
534 iscsi_conn_printk(KERN_ERR, conn,
535 "invalid R2t with datalen %d\n",
536 tcp_conn->in.datalen);
537 return ISCSI_ERR_DATALEN;
538 }
539
540 if (tcp_task->exp_datasn != r2tsn){
541 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
542 tcp_task->exp_datasn, r2tsn);
543 return ISCSI_ERR_R2TSN;
544 }
545
546 /* fill-in new R2T associated with the task */
547 iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
548
549 if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
550 iscsi_conn_printk(KERN_INFO, conn,
551 "dropping R2T itt %d in recovery.\n",
552 task->itt);
553 return 0;
554 }
555
556 rc = kfifo_out(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
557 if (!rc) {
558 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
559 "Target has sent more R2Ts than it "
560 "negotiated for or driver has has leaked.\n");
561 return ISCSI_ERR_PROTO;
562 }
563
564 r2t->exp_statsn = rhdr->statsn;
565 r2t->data_length = be32_to_cpu(rhdr->data_length);
566 if (r2t->data_length == 0) {
567 iscsi_conn_printk(KERN_ERR, conn,
568 "invalid R2T with zero data len\n");
569 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
570 sizeof(void*));
571 return ISCSI_ERR_DATALEN;
572 }
573
574 if (r2t->data_length > session->max_burst)
575 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
576 "burst %u. Attempting to execute request.\n",
577 r2t->data_length, session->max_burst);
578
579 r2t->data_offset = be32_to_cpu(rhdr->data_offset);
580 if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
581 iscsi_conn_printk(KERN_ERR, conn,
582 "invalid R2T with data len %u at offset %u "
583 "and total length %d\n", r2t->data_length,
584 r2t->data_offset, scsi_out(task->sc)->length);
585 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
586 sizeof(void*));
587 return ISCSI_ERR_DATALEN;
588 }
589
590 r2t->ttt = rhdr->ttt; /* no flip */
591 r2t->datasn = 0;
592 r2t->sent = 0;
593
594 tcp_task->exp_datasn = r2tsn + 1;
595 kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
596 conn->r2t_pdus_cnt++;
597
598 iscsi_requeue_task(task);
599 return 0;
600}
601
602/*
603 * Handle incoming reply to DataIn command
604 */
605static int
606iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
607 struct iscsi_segment *segment)
608{
609 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
610 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
611 int rc;
612
613 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
614 return ISCSI_ERR_DATA_DGST;
615
616 /* check for non-exceptional status */
617 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
618 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
619 if (rc)
620 return rc;
621 }
622
623 iscsi_tcp_hdr_recv_prep(tcp_conn);
624 return 0;
625}
626
627/**
628 * iscsi_tcp_hdr_dissect - process PDU header
629 * @conn: iSCSI connection
630 * @hdr: PDU header
631 *
632 * This function analyzes the header of the PDU received,
633 * and performs several sanity checks. If the PDU is accompanied
634 * by data, the receive buffer is set up to copy the incoming data
635 * to the correct location.
636 */
637static int
638iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
639{
640 int rc = 0, opcode, ahslen;
641 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
642 struct iscsi_task *task;
643
644 /* verify PDU length */
645 tcp_conn->in.datalen = ntoh24(hdr->dlength);
646 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
647 iscsi_conn_printk(KERN_ERR, conn,
648 "iscsi_tcp: datalen %d > %d\n",
649 tcp_conn->in.datalen, conn->max_recv_dlength);
650 return ISCSI_ERR_DATALEN;
651 }
652
653 /* Additional header segments. So far, we don't
654 * process additional headers.
655 */
656 ahslen = hdr->hlength << 2;
657
658 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
659 /* verify itt (itt encoding: age+cid+itt) */
660 rc = iscsi_verify_itt(conn, hdr->itt);
661 if (rc)
662 return rc;
663
664 ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
665 opcode, ahslen, tcp_conn->in.datalen);
666
667 switch(opcode) {
668 case ISCSI_OP_SCSI_DATA_IN:
669 spin_lock(&conn->session->lock);
670 task = iscsi_itt_to_ctask(conn, hdr->itt);
671 if (!task)
672 rc = ISCSI_ERR_BAD_ITT;
673 else
674 rc = iscsi_tcp_data_in(conn, task);
675 if (rc) {
676 spin_unlock(&conn->session->lock);
677 break;
678 }
679
680 if (tcp_conn->in.datalen) {
681 struct iscsi_tcp_task *tcp_task = task->dd_data;
682 struct hash_desc *rx_hash = NULL;
683 struct scsi_data_buffer *sdb = scsi_in(task->sc);
684
685 /*
686 * Setup copy of Data-In into the Scsi_Cmnd
687 * Scatterlist case:
688 * We set up the iscsi_segment to point to the next
689 * scatterlist entry to copy to. As we go along,
690 * we move on to the next scatterlist entry and
691 * update the digest per-entry.
692 */
693 if (conn->datadgst_en &&
694 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
695 rx_hash = tcp_conn->rx_hash;
696
697 ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
698 "offset=%d, datalen=%d)\n",
699 tcp_task->data_offset,
700 tcp_conn->in.datalen);
701 task->last_xfer = jiffies;
702 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
703 sdb->table.sgl,
704 sdb->table.nents,
705 tcp_task->data_offset,
706 tcp_conn->in.datalen,
707 iscsi_tcp_process_data_in,
708 rx_hash);
709 spin_unlock(&conn->session->lock);
710 return rc;
711 }
712 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
713 spin_unlock(&conn->session->lock);
714 break;
715 case ISCSI_OP_SCSI_CMD_RSP:
716 if (tcp_conn->in.datalen) {
717 iscsi_tcp_data_recv_prep(tcp_conn);
718 return 0;
719 }
720 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
721 break;
722 case ISCSI_OP_R2T:
723 spin_lock(&conn->session->lock);
724 task = iscsi_itt_to_ctask(conn, hdr->itt);
725 if (!task)
726 rc = ISCSI_ERR_BAD_ITT;
727 else if (ahslen)
728 rc = ISCSI_ERR_AHSLEN;
729 else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
730 task->last_xfer = jiffies;
731 rc = iscsi_tcp_r2t_rsp(conn, task);
732 } else
733 rc = ISCSI_ERR_PROTO;
734 spin_unlock(&conn->session->lock);
735 break;
736 case ISCSI_OP_LOGIN_RSP:
737 case ISCSI_OP_TEXT_RSP:
738 case ISCSI_OP_REJECT:
739 case ISCSI_OP_ASYNC_EVENT:
740 /*
741 * It is possible that we could get a PDU with a buffer larger
742 * than 8K, but there are no targets that currently do this.
743 * For now we fail until we find a vendor that needs it
744 */
745 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
746 iscsi_conn_printk(KERN_ERR, conn,
747 "iscsi_tcp: received buffer of "
748 "len %u but conn buffer is only %u "
749 "(opcode %0x)\n",
750 tcp_conn->in.datalen,
751 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
752 rc = ISCSI_ERR_PROTO;
753 break;
754 }
755
756 /* If there's data coming in with the response,
757 * receive it to the connection's buffer.
758 */
759 if (tcp_conn->in.datalen) {
760 iscsi_tcp_data_recv_prep(tcp_conn);
761 return 0;
762 }
763 /* fall through */
764 case ISCSI_OP_LOGOUT_RSP:
765 case ISCSI_OP_NOOP_IN:
766 case ISCSI_OP_SCSI_TMFUNC_RSP:
767 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
768 break;
769 default:
770 rc = ISCSI_ERR_BAD_OPCODE;
771 break;
772 }
773
774 if (rc == 0) {
775 /* Anything that comes with data should have
776 * been handled above. */
777 if (tcp_conn->in.datalen)
778 return ISCSI_ERR_PROTO;
779 iscsi_tcp_hdr_recv_prep(tcp_conn);
780 }
781
782 return rc;
783}
784
785/**
786 * iscsi_tcp_hdr_recv_done - process PDU header
787 *
788 * This is the callback invoked when the PDU header has
789 * been received. If the header is followed by additional
790 * header segments, we go back for more data.
791 */
792static int
793iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
794 struct iscsi_segment *segment)
795{
796 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
797 struct iscsi_hdr *hdr;
798
799 /* Check if there are additional header segments
800 * *prior* to computing the digest, because we
801 * may need to go back to the caller for more.
802 */
803 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
804 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
805 /* Bump the header length - the caller will
806 * just loop around and get the AHS for us, and
807 * call again. */
808 unsigned int ahslen = hdr->hlength << 2;
809
810 /* Make sure we don't overflow */
811 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
812 return ISCSI_ERR_AHSLEN;
813
814 segment->total_size += ahslen;
815 segment->size += ahslen;
816 return 0;
817 }
818
819 /* We're done processing the header. See if we're doing
820 * header digests; if so, set up the recv_digest buffer
821 * and go back for more. */
822 if (conn->hdrdgst_en &&
823 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
824 if (segment->digest_len == 0) {
825 /*
826 * Even if we offload the digest processing we
827 * splice it in so we can increment the skb/segment
828 * counters in preparation for the data segment.
829 */
830 iscsi_tcp_segment_splice_digest(segment,
831 segment->recv_digest);
832 return 0;
833 }
834
835 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
836 segment->total_copied - ISCSI_DIGEST_SIZE,
837 segment->digest);
838
839 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
840 return ISCSI_ERR_HDR_DGST;
841 }
842
843 tcp_conn->in.hdr = hdr;
844 return iscsi_tcp_hdr_dissect(conn, hdr);
845}
846
847/**
848 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
849 * @tcp_conn: iscsi tcp conn
850 *
851 * returns non zero if we are currently processing or setup to process
852 * a header.
853 */
854inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
855{
856 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
857}
858EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
859
860/**
861 * iscsi_tcp_recv_skb - Process skb
862 * @conn: iscsi connection
863 * @skb: network buffer with header and/or data segment
864 * @offset: offset in skb
865 * @offload: bool indicating if transfer was offloaded
866 *
867 * Will return status of transfer in status. And will return
868 * number of bytes copied.
869 */
870int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
871 unsigned int offset, bool offloaded, int *status)
872{
873 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
874 struct iscsi_segment *segment = &tcp_conn->in.segment;
875 struct skb_seq_state seq;
876 unsigned int consumed = 0;
877 int rc = 0;
878
879 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
880 /*
881 * Update for each skb instead of pdu, because over slow networks a
882 * data_in's data could take a while to read in. We also want to
883 * account for r2ts.
884 */
885 conn->last_recv = jiffies;
886
887 if (unlikely(conn->suspend_rx)) {
888 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
889 *status = ISCSI_TCP_SUSPENDED;
890 return 0;
891 }
892
893 if (offloaded) {
894 segment->total_copied = segment->total_size;
895 goto segment_done;
896 }
897
898 skb_prepare_seq_read(skb, offset, skb->len, &seq);
899 while (1) {
900 unsigned int avail;
901 const u8 *ptr;
902
903 avail = skb_seq_read(consumed, &ptr, &seq);
904 if (avail == 0) {
905 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
906 consumed);
907 *status = ISCSI_TCP_SKB_DONE;
908 skb_abort_seq_read(&seq);
909 goto skb_done;
910 }
911 BUG_ON(segment->copied >= segment->size);
912
913 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
914 avail);
915 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
916 BUG_ON(rc == 0);
917 consumed += rc;
918
919 if (segment->total_copied >= segment->total_size) {
920 skb_abort_seq_read(&seq);
921 goto segment_done;
922 }
923 }
924
925segment_done:
926 *status = ISCSI_TCP_SEGMENT_DONE;
927 ISCSI_DBG_TCP(conn, "segment done\n");
928 rc = segment->done(tcp_conn, segment);
929 if (rc != 0) {
930 *status = ISCSI_TCP_CONN_ERR;
931 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
932 iscsi_conn_failure(conn, rc);
933 return 0;
934 }
935 /* The done() functions sets up the next segment. */
936
937skb_done:
938 conn->rxdata_octets += consumed;
939 return consumed;
940}
941EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
942
943/**
944 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
945 * @conn: iscsi connection
946 * @task: scsi command task
947 * @sc: scsi command
948 */
949int iscsi_tcp_task_init(struct iscsi_task *task)
950{
951 struct iscsi_tcp_task *tcp_task = task->dd_data;
952 struct iscsi_conn *conn = task->conn;
953 struct scsi_cmnd *sc = task->sc;
954 int err;
955
956 if (!sc) {
957 /*
958 * mgmt tasks do not have a scatterlist since they come
959 * in from the iscsi interface.
960 */
961 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
962
963 return conn->session->tt->init_pdu(task, 0, task->data_count);
964 }
965
966 BUG_ON(kfifo_len(&tcp_task->r2tqueue));
967 tcp_task->exp_datasn = 0;
968
969 /* Prepare PDU, optionally w/ immediate data */
970 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
971 task->itt, task->imm_count, task->unsol_r2t.data_length);
972
973 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
974 if (err)
975 return err;
976 task->imm_count = 0;
977 return 0;
978}
979EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
980
981static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
982{
983 struct iscsi_session *session = task->conn->session;
984 struct iscsi_tcp_task *tcp_task = task->dd_data;
985 struct iscsi_r2t_info *r2t = NULL;
986
987 if (iscsi_task_has_unsol_data(task))
988 r2t = &task->unsol_r2t;
989 else {
990 spin_lock_bh(&session->lock);
991 if (tcp_task->r2t) {
992 r2t = tcp_task->r2t;
993 /* Continue with this R2T? */
994 if (r2t->data_length <= r2t->sent) {
995 ISCSI_DBG_TCP(task->conn,
996 " done with r2t %p\n", r2t);
997 kfifo_in(&tcp_task->r2tpool.queue,
998 (void *)&tcp_task->r2t,
999 sizeof(void *));
1000 tcp_task->r2t = r2t = NULL;
1001 }
1002 }
1003
1004 if (r2t == NULL) {
1005 if (kfifo_out(&tcp_task->r2tqueue,
1006 (void *)&tcp_task->r2t, sizeof(void *)) !=
1007 sizeof(void *))
1008 r2t = NULL;
1009 else
1010 r2t = tcp_task->r2t;
1011 }
1012 spin_unlock_bh(&session->lock);
1013 }
1014
1015 return r2t;
1016}
1017
1018/**
1019 * iscsi_tcp_task_xmit - xmit normal PDU task
1020 * @task: iscsi command task
1021 *
1022 * We're expected to return 0 when everything was transmitted successfully,
1023 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1024 * of error.
1025 */
1026int iscsi_tcp_task_xmit(struct iscsi_task *task)
1027{
1028 struct iscsi_conn *conn = task->conn;
1029 struct iscsi_session *session = conn->session;
1030 struct iscsi_r2t_info *r2t;
1031 int rc = 0;
1032
1033flush:
1034 /* Flush any pending data first. */
1035 rc = session->tt->xmit_pdu(task);
1036 if (rc < 0)
1037 return rc;
1038
1039 /* mgmt command */
1040 if (!task->sc) {
1041 if (task->hdr->itt == RESERVED_ITT)
1042 iscsi_put_task(task);
1043 return 0;
1044 }
1045
1046 /* Are we done already? */
1047 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1048 return 0;
1049
1050 r2t = iscsi_tcp_get_curr_r2t(task);
1051 if (r2t == NULL) {
1052 /* Waiting for more R2Ts to arrive. */
1053 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1054 return 0;
1055 }
1056
1057 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1058 if (rc)
1059 return rc;
1060 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1061
1062 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1063 r2t, r2t->datasn - 1, task->hdr->itt,
1064 r2t->data_offset + r2t->sent, r2t->data_count);
1065
1066 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1067 r2t->data_count);
1068 if (rc) {
1069 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1070 return rc;
1071 }
1072
1073 r2t->sent += r2t->data_count;
1074 goto flush;
1075}
1076EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1077
1078struct iscsi_cls_conn *
1079iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1080 uint32_t conn_idx)
1081
1082{
1083 struct iscsi_conn *conn;
1084 struct iscsi_cls_conn *cls_conn;
1085 struct iscsi_tcp_conn *tcp_conn;
1086
1087 cls_conn = iscsi_conn_setup(cls_session,
1088 sizeof(*tcp_conn) + dd_data_size, conn_idx);
1089 if (!cls_conn)
1090 return NULL;
1091 conn = cls_conn->dd_data;
1092 /*
1093 * due to strange issues with iser these are not set
1094 * in iscsi_conn_setup
1095 */
1096 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1097
1098 tcp_conn = conn->dd_data;
1099 tcp_conn->iscsi_conn = conn;
1100 tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1101 return cls_conn;
1102}
1103EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1104
1105void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1106{
1107 iscsi_conn_teardown(cls_conn);
1108}
1109EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1110
1111int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1112{
1113 int i;
1114 int cmd_i;
1115
1116 /*
1117 * initialize per-task: R2T pool and xmit queue
1118 */
1119 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1120 struct iscsi_task *task = session->cmds[cmd_i];
1121 struct iscsi_tcp_task *tcp_task = task->dd_data;
1122
1123 /*
1124 * pre-allocated x2 as much r2ts to handle race when
1125 * target acks DataOut faster than we data_xmit() queues
1126 * could replenish r2tqueue.
1127 */
1128
1129 /* R2T pool */
1130 if (iscsi_pool_init(&tcp_task->r2tpool,
1131 session->max_r2t * 2, NULL,
1132 sizeof(struct iscsi_r2t_info))) {
1133 goto r2t_alloc_fail;
1134 }
1135
1136 /* R2T xmit queue */
1137 if (kfifo_alloc(&tcp_task->r2tqueue,
1138 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1139 iscsi_pool_free(&tcp_task->r2tpool);
1140 goto r2t_alloc_fail;
1141 }
1142 }
1143
1144 return 0;
1145
1146r2t_alloc_fail:
1147 for (i = 0; i < cmd_i; i++) {
1148 struct iscsi_task *task = session->cmds[i];
1149 struct iscsi_tcp_task *tcp_task = task->dd_data;
1150
1151 kfifo_free(&tcp_task->r2tqueue);
1152 iscsi_pool_free(&tcp_task->r2tpool);
1153 }
1154 return -ENOMEM;
1155}
1156EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1157
1158void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1159{
1160 int i;
1161
1162 for (i = 0; i < session->cmds_max; i++) {
1163 struct iscsi_task *task = session->cmds[i];
1164 struct iscsi_tcp_task *tcp_task = task->dd_data;
1165
1166 kfifo_free(&tcp_task->r2tqueue);
1167 iscsi_pool_free(&tcp_task->r2tpool);
1168 }
1169}
1170EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1171
1172void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1173 struct iscsi_stats *stats)
1174{
1175 struct iscsi_conn *conn = cls_conn->dd_data;
1176
1177 stats->txdata_octets = conn->txdata_octets;
1178 stats->rxdata_octets = conn->rxdata_octets;
1179 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1180 stats->dataout_pdus = conn->dataout_pdus_cnt;
1181 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1182 stats->datain_pdus = conn->datain_pdus_cnt;
1183 stats->r2t_pdus = conn->r2t_pdus_cnt;
1184 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1185 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1186}
1187EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);