/drivers/scsi/libiscsi_tcp.c
C | 1184 lines | 769 code | 144 blank | 271 comment | 115 complexity | 47b40b80d24c60afa7be3d09ca6a4651 MD5 | raw file
Possible License(s): CC-BY-SA-3.0, GPL-2.0, LGPL-2.0, AGPL-1.0
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 segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
136 segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
137}
138
139void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
140{
141 if (segment->sg_mapped) {
142 kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
143 segment->sg_mapped = NULL;
144 segment->data = NULL;
145 }
146}
147EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
148
149/*
150 * Splice the digest buffer into the buffer
151 */
152static inline void
153iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
154{
155 segment->data = digest;
156 segment->digest_len = ISCSI_DIGEST_SIZE;
157 segment->total_size += ISCSI_DIGEST_SIZE;
158 segment->size = ISCSI_DIGEST_SIZE;
159 segment->copied = 0;
160 segment->sg = NULL;
161 segment->hash = NULL;
162}
163
164/**
165 * iscsi_tcp_segment_done - check whether the segment is complete
166 * @tcp_conn: iscsi tcp connection
167 * @segment: iscsi segment to check
168 * @recv: set to one of this is called from the recv path
169 * @copied: number of bytes copied
170 *
171 * Check if we're done receiving this segment. If the receive
172 * buffer is full but we expect more data, move on to the
173 * next entry in the scatterlist.
174 *
175 * If the amount of data we received isn't a multiple of 4,
176 * we will transparently receive the pad bytes, too.
177 *
178 * This function must be re-entrant.
179 */
180int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
181 struct iscsi_segment *segment, int recv,
182 unsigned copied)
183{
184 struct scatterlist sg;
185 unsigned int pad;
186
187 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
188 segment->copied, copied, segment->size,
189 recv ? "recv" : "xmit");
190 if (segment->hash && copied) {
191 /*
192 * If a segment is kmapd we must unmap it before sending
193 * to the crypto layer since that will try to kmap it again.
194 */
195 iscsi_tcp_segment_unmap(segment);
196
197 if (!segment->data) {
198 sg_init_table(&sg, 1);
199 sg_set_page(&sg, sg_page(segment->sg), copied,
200 segment->copied + segment->sg_offset +
201 segment->sg->offset);
202 } else
203 sg_init_one(&sg, segment->data + segment->copied,
204 copied);
205 crypto_hash_update(segment->hash, &sg, copied);
206 }
207
208 segment->copied += copied;
209 if (segment->copied < segment->size) {
210 iscsi_tcp_segment_map(segment, recv);
211 return 0;
212 }
213
214 segment->total_copied += segment->copied;
215 segment->copied = 0;
216 segment->size = 0;
217
218 /* Unmap the current scatterlist page, if there is one. */
219 iscsi_tcp_segment_unmap(segment);
220
221 /* Do we have more scatterlist entries? */
222 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
223 segment->total_copied, segment->total_size);
224 if (segment->total_copied < segment->total_size) {
225 /* Proceed to the next entry in the scatterlist. */
226 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
227 0);
228 iscsi_tcp_segment_map(segment, recv);
229 BUG_ON(segment->size == 0);
230 return 0;
231 }
232
233 /* Do we need to handle padding? */
234 if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
235 pad = iscsi_padding(segment->total_copied);
236 if (pad != 0) {
237 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
238 "consume %d pad bytes\n", pad);
239 segment->total_size += pad;
240 segment->size = pad;
241 segment->data = segment->padbuf;
242 return 0;
243 }
244 }
245
246 /*
247 * Set us up for transferring the data digest. hdr digest
248 * is completely handled in hdr done function.
249 */
250 if (segment->hash) {
251 crypto_hash_final(segment->hash, segment->digest);
252 iscsi_tcp_segment_splice_digest(segment,
253 recv ? segment->recv_digest : segment->digest);
254 return 0;
255 }
256
257 return 1;
258}
259EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
260
261/**
262 * iscsi_tcp_segment_recv - copy data to segment
263 * @tcp_conn: the iSCSI TCP connection
264 * @segment: the buffer to copy to
265 * @ptr: data pointer
266 * @len: amount of data available
267 *
268 * This function copies up to @len bytes to the
269 * given buffer, and returns the number of bytes
270 * consumed, which can actually be less than @len.
271 *
272 * If hash digest is enabled, the function will update the
273 * hash while copying.
274 * Combining these two operations doesn't buy us a lot (yet),
275 * but in the future we could implement combined copy+crc,
276 * just way we do for network layer checksums.
277 */
278static int
279iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
280 struct iscsi_segment *segment, const void *ptr,
281 unsigned int len)
282{
283 unsigned int copy = 0, copied = 0;
284
285 while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
286 if (copied == len) {
287 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
288 "copied %d bytes\n", len);
289 break;
290 }
291
292 copy = min(len - copied, segment->size - segment->copied);
293 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
294 memcpy(segment->data + segment->copied, ptr + copied, copy);
295 copied += copy;
296 }
297 return copied;
298}
299
300inline void
301iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
302 unsigned char digest[ISCSI_DIGEST_SIZE])
303{
304 struct scatterlist sg;
305
306 sg_init_one(&sg, hdr, hdrlen);
307 crypto_hash_digest(hash, &sg, hdrlen, digest);
308}
309EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
310
311static inline int
312iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
313 struct iscsi_segment *segment)
314{
315 if (!segment->digest_len)
316 return 1;
317
318 if (memcmp(segment->recv_digest, segment->digest,
319 segment->digest_len)) {
320 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
321 return 0;
322 }
323
324 return 1;
325}
326
327/*
328 * Helper function to set up segment buffer
329 */
330static inline void
331__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
332 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
333{
334 memset(segment, 0, sizeof(*segment));
335 segment->total_size = size;
336 segment->done = done;
337
338 if (hash) {
339 segment->hash = hash;
340 crypto_hash_init(hash);
341 }
342}
343
344inline void
345iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
346 size_t size, iscsi_segment_done_fn_t *done,
347 struct hash_desc *hash)
348{
349 __iscsi_segment_init(segment, size, done, hash);
350 segment->data = data;
351 segment->size = size;
352}
353EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
354
355inline int
356iscsi_segment_seek_sg(struct iscsi_segment *segment,
357 struct scatterlist *sg_list, unsigned int sg_count,
358 unsigned int offset, size_t size,
359 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
360{
361 struct scatterlist *sg;
362 unsigned int i;
363
364 __iscsi_segment_init(segment, size, done, hash);
365 for_each_sg(sg_list, sg, sg_count, i) {
366 if (offset < sg->length) {
367 iscsi_tcp_segment_init_sg(segment, sg, offset);
368 return 0;
369 }
370 offset -= sg->length;
371 }
372
373 return ISCSI_ERR_DATA_OFFSET;
374}
375EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
376
377/**
378 * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
379 * @tcp_conn: iscsi connection to prep for
380 *
381 * This function always passes NULL for the hash argument, because when this
382 * function is called we do not yet know the final size of the header and want
383 * to delay the digest processing until we know that.
384 */
385void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
386{
387 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
388 "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
389 "digest enabled" : "digest disabled");
390 iscsi_segment_init_linear(&tcp_conn->in.segment,
391 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
392 iscsi_tcp_hdr_recv_done, NULL);
393}
394EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
395
396/*
397 * Handle incoming reply to any other type of command
398 */
399static int
400iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
401 struct iscsi_segment *segment)
402{
403 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
404 int rc = 0;
405
406 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
407 return ISCSI_ERR_DATA_DGST;
408
409 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
410 conn->data, tcp_conn->in.datalen);
411 if (rc)
412 return rc;
413
414 iscsi_tcp_hdr_recv_prep(tcp_conn);
415 return 0;
416}
417
418static void
419iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
420{
421 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
422 struct hash_desc *rx_hash = NULL;
423
424 if (conn->datadgst_en &
425 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
426 rx_hash = tcp_conn->rx_hash;
427
428 iscsi_segment_init_linear(&tcp_conn->in.segment,
429 conn->data, tcp_conn->in.datalen,
430 iscsi_tcp_data_recv_done, rx_hash);
431}
432
433/**
434 * iscsi_tcp_cleanup_task - free tcp_task resources
435 * @task: iscsi task
436 *
437 * must be called with session lock
438 */
439void iscsi_tcp_cleanup_task(struct iscsi_task *task)
440{
441 struct iscsi_tcp_task *tcp_task = task->dd_data;
442 struct iscsi_r2t_info *r2t;
443
444 /* nothing to do for mgmt */
445 if (!task->sc)
446 return;
447
448 /* flush task's r2t queues */
449 while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
450 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
451 sizeof(void*));
452 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
453 }
454
455 r2t = tcp_task->r2t;
456 if (r2t != NULL) {
457 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
458 sizeof(void*));
459 tcp_task->r2t = NULL;
460 }
461}
462EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
463
464/**
465 * iscsi_tcp_data_in - SCSI Data-In Response processing
466 * @conn: iscsi connection
467 * @task: scsi command task
468 */
469static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
470{
471 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
472 struct iscsi_tcp_task *tcp_task = task->dd_data;
473 struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
474 int datasn = be32_to_cpu(rhdr->datasn);
475 unsigned total_in_length = scsi_in(task->sc)->length;
476
477 /*
478 * lib iscsi will update this in the completion handling if there
479 * is status.
480 */
481 if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
482 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
483
484 if (tcp_conn->in.datalen == 0)
485 return 0;
486
487 if (tcp_task->exp_datasn != datasn) {
488 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
489 "\n", tcp_task->exp_datasn, datasn);
490 return ISCSI_ERR_DATASN;
491 }
492
493 tcp_task->exp_datasn++;
494
495 tcp_task->data_offset = be32_to_cpu(rhdr->offset);
496 if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
497 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
498 "total_length_in(%d)\n", tcp_task->data_offset,
499 tcp_conn->in.datalen, total_in_length);
500 return ISCSI_ERR_DATA_OFFSET;
501 }
502
503 conn->datain_pdus_cnt++;
504 return 0;
505}
506
507/**
508 * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
509 * @conn: iscsi connection
510 * @task: scsi command task
511 */
512static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
513{
514 struct iscsi_session *session = conn->session;
515 struct iscsi_tcp_task *tcp_task = task->dd_data;
516 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
517 struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
518 struct iscsi_r2t_info *r2t;
519 int r2tsn = be32_to_cpu(rhdr->r2tsn);
520 int rc;
521
522 if (tcp_conn->in.datalen) {
523 iscsi_conn_printk(KERN_ERR, conn,
524 "invalid R2t with datalen %d\n",
525 tcp_conn->in.datalen);
526 return ISCSI_ERR_DATALEN;
527 }
528
529 if (tcp_task->exp_datasn != r2tsn){
530 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
531 tcp_task->exp_datasn, r2tsn);
532 return ISCSI_ERR_R2TSN;
533 }
534
535 /* fill-in new R2T associated with the task */
536 iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
537
538 if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
539 iscsi_conn_printk(KERN_INFO, conn,
540 "dropping R2T itt %d in recovery.\n",
541 task->itt);
542 return 0;
543 }
544
545 rc = kfifo_out(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
546 if (!rc) {
547 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
548 "Target has sent more R2Ts than it "
549 "negotiated for or driver has has leaked.\n");
550 return ISCSI_ERR_PROTO;
551 }
552
553 r2t->exp_statsn = rhdr->statsn;
554 r2t->data_length = be32_to_cpu(rhdr->data_length);
555 if (r2t->data_length == 0) {
556 iscsi_conn_printk(KERN_ERR, conn,
557 "invalid R2T with zero data len\n");
558 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
559 sizeof(void*));
560 return ISCSI_ERR_DATALEN;
561 }
562
563 if (r2t->data_length > session->max_burst)
564 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
565 "burst %u. Attempting to execute request.\n",
566 r2t->data_length, session->max_burst);
567
568 r2t->data_offset = be32_to_cpu(rhdr->data_offset);
569 if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
570 iscsi_conn_printk(KERN_ERR, conn,
571 "invalid R2T with data len %u at offset %u "
572 "and total length %d\n", r2t->data_length,
573 r2t->data_offset, scsi_out(task->sc)->length);
574 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
575 sizeof(void*));
576 return ISCSI_ERR_DATALEN;
577 }
578
579 r2t->ttt = rhdr->ttt; /* no flip */
580 r2t->datasn = 0;
581 r2t->sent = 0;
582
583 tcp_task->exp_datasn = r2tsn + 1;
584 kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
585 conn->r2t_pdus_cnt++;
586
587 iscsi_requeue_task(task);
588 return 0;
589}
590
591/*
592 * Handle incoming reply to DataIn command
593 */
594static int
595iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
596 struct iscsi_segment *segment)
597{
598 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
599 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
600 int rc;
601
602 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
603 return ISCSI_ERR_DATA_DGST;
604
605 /* check for non-exceptional status */
606 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
607 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
608 if (rc)
609 return rc;
610 }
611
612 iscsi_tcp_hdr_recv_prep(tcp_conn);
613 return 0;
614}
615
616/**
617 * iscsi_tcp_hdr_dissect - process PDU header
618 * @conn: iSCSI connection
619 * @hdr: PDU header
620 *
621 * This function analyzes the header of the PDU received,
622 * and performs several sanity checks. If the PDU is accompanied
623 * by data, the receive buffer is set up to copy the incoming data
624 * to the correct location.
625 */
626static int
627iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
628{
629 int rc = 0, opcode, ahslen;
630 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
631 struct iscsi_task *task;
632
633 /* verify PDU length */
634 tcp_conn->in.datalen = ntoh24(hdr->dlength);
635 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
636 iscsi_conn_printk(KERN_ERR, conn,
637 "iscsi_tcp: datalen %d > %d\n",
638 tcp_conn->in.datalen, conn->max_recv_dlength);
639 return ISCSI_ERR_DATALEN;
640 }
641
642 /* Additional header segments. So far, we don't
643 * process additional headers.
644 */
645 ahslen = hdr->hlength << 2;
646
647 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
648 /* verify itt (itt encoding: age+cid+itt) */
649 rc = iscsi_verify_itt(conn, hdr->itt);
650 if (rc)
651 return rc;
652
653 ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
654 opcode, ahslen, tcp_conn->in.datalen);
655
656 switch(opcode) {
657 case ISCSI_OP_SCSI_DATA_IN:
658 spin_lock(&conn->session->lock);
659 task = iscsi_itt_to_ctask(conn, hdr->itt);
660 if (!task)
661 rc = ISCSI_ERR_BAD_ITT;
662 else
663 rc = iscsi_tcp_data_in(conn, task);
664 if (rc) {
665 spin_unlock(&conn->session->lock);
666 break;
667 }
668
669 if (tcp_conn->in.datalen) {
670 struct iscsi_tcp_task *tcp_task = task->dd_data;
671 struct hash_desc *rx_hash = NULL;
672 struct scsi_data_buffer *sdb = scsi_in(task->sc);
673
674 /*
675 * Setup copy of Data-In into the Scsi_Cmnd
676 * Scatterlist case:
677 * We set up the iscsi_segment to point to the next
678 * scatterlist entry to copy to. As we go along,
679 * we move on to the next scatterlist entry and
680 * update the digest per-entry.
681 */
682 if (conn->datadgst_en &&
683 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
684 rx_hash = tcp_conn->rx_hash;
685
686 ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
687 "offset=%d, datalen=%d)\n",
688 tcp_task->data_offset,
689 tcp_conn->in.datalen);
690 task->last_xfer = jiffies;
691 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
692 sdb->table.sgl,
693 sdb->table.nents,
694 tcp_task->data_offset,
695 tcp_conn->in.datalen,
696 iscsi_tcp_process_data_in,
697 rx_hash);
698 spin_unlock(&conn->session->lock);
699 return rc;
700 }
701 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
702 spin_unlock(&conn->session->lock);
703 break;
704 case ISCSI_OP_SCSI_CMD_RSP:
705 if (tcp_conn->in.datalen) {
706 iscsi_tcp_data_recv_prep(tcp_conn);
707 return 0;
708 }
709 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
710 break;
711 case ISCSI_OP_R2T:
712 spin_lock(&conn->session->lock);
713 task = iscsi_itt_to_ctask(conn, hdr->itt);
714 if (!task)
715 rc = ISCSI_ERR_BAD_ITT;
716 else if (ahslen)
717 rc = ISCSI_ERR_AHSLEN;
718 else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
719 task->last_xfer = jiffies;
720 rc = iscsi_tcp_r2t_rsp(conn, task);
721 } else
722 rc = ISCSI_ERR_PROTO;
723 spin_unlock(&conn->session->lock);
724 break;
725 case ISCSI_OP_LOGIN_RSP:
726 case ISCSI_OP_TEXT_RSP:
727 case ISCSI_OP_REJECT:
728 case ISCSI_OP_ASYNC_EVENT:
729 /*
730 * It is possible that we could get a PDU with a buffer larger
731 * than 8K, but there are no targets that currently do this.
732 * For now we fail until we find a vendor that needs it
733 */
734 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
735 iscsi_conn_printk(KERN_ERR, conn,
736 "iscsi_tcp: received buffer of "
737 "len %u but conn buffer is only %u "
738 "(opcode %0x)\n",
739 tcp_conn->in.datalen,
740 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
741 rc = ISCSI_ERR_PROTO;
742 break;
743 }
744
745 /* If there's data coming in with the response,
746 * receive it to the connection's buffer.
747 */
748 if (tcp_conn->in.datalen) {
749 iscsi_tcp_data_recv_prep(tcp_conn);
750 return 0;
751 }
752 /* fall through */
753 case ISCSI_OP_LOGOUT_RSP:
754 case ISCSI_OP_NOOP_IN:
755 case ISCSI_OP_SCSI_TMFUNC_RSP:
756 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
757 break;
758 default:
759 rc = ISCSI_ERR_BAD_OPCODE;
760 break;
761 }
762
763 if (rc == 0) {
764 /* Anything that comes with data should have
765 * been handled above. */
766 if (tcp_conn->in.datalen)
767 return ISCSI_ERR_PROTO;
768 iscsi_tcp_hdr_recv_prep(tcp_conn);
769 }
770
771 return rc;
772}
773
774/**
775 * iscsi_tcp_hdr_recv_done - process PDU header
776 *
777 * This is the callback invoked when the PDU header has
778 * been received. If the header is followed by additional
779 * header segments, we go back for more data.
780 */
781static int
782iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
783 struct iscsi_segment *segment)
784{
785 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
786 struct iscsi_hdr *hdr;
787
788 /* Check if there are additional header segments
789 * *prior* to computing the digest, because we
790 * may need to go back to the caller for more.
791 */
792 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
793 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
794 /* Bump the header length - the caller will
795 * just loop around and get the AHS for us, and
796 * call again. */
797 unsigned int ahslen = hdr->hlength << 2;
798
799 /* Make sure we don't overflow */
800 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
801 return ISCSI_ERR_AHSLEN;
802
803 segment->total_size += ahslen;
804 segment->size += ahslen;
805 return 0;
806 }
807
808 /* We're done processing the header. See if we're doing
809 * header digests; if so, set up the recv_digest buffer
810 * and go back for more. */
811 if (conn->hdrdgst_en &&
812 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
813 if (segment->digest_len == 0) {
814 /*
815 * Even if we offload the digest processing we
816 * splice it in so we can increment the skb/segment
817 * counters in preparation for the data segment.
818 */
819 iscsi_tcp_segment_splice_digest(segment,
820 segment->recv_digest);
821 return 0;
822 }
823
824 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
825 segment->total_copied - ISCSI_DIGEST_SIZE,
826 segment->digest);
827
828 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
829 return ISCSI_ERR_HDR_DGST;
830 }
831
832 tcp_conn->in.hdr = hdr;
833 return iscsi_tcp_hdr_dissect(conn, hdr);
834}
835
836/**
837 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
838 * @tcp_conn: iscsi tcp conn
839 *
840 * returns non zero if we are currently processing or setup to process
841 * a header.
842 */
843inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
844{
845 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
846}
847EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
848
849/**
850 * iscsi_tcp_recv_skb - Process skb
851 * @conn: iscsi connection
852 * @skb: network buffer with header and/or data segment
853 * @offset: offset in skb
854 * @offload: bool indicating if transfer was offloaded
855 *
856 * Will return status of transfer in status. And will return
857 * number of bytes copied.
858 */
859int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
860 unsigned int offset, bool offloaded, int *status)
861{
862 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
863 struct iscsi_segment *segment = &tcp_conn->in.segment;
864 struct skb_seq_state seq;
865 unsigned int consumed = 0;
866 int rc = 0;
867
868 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
869 /*
870 * Update for each skb instead of pdu, because over slow networks a
871 * data_in's data could take a while to read in. We also want to
872 * account for r2ts.
873 */
874 conn->last_recv = jiffies;
875
876 if (unlikely(conn->suspend_rx)) {
877 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
878 *status = ISCSI_TCP_SUSPENDED;
879 return 0;
880 }
881
882 if (offloaded) {
883 segment->total_copied = segment->total_size;
884 goto segment_done;
885 }
886
887 skb_prepare_seq_read(skb, offset, skb->len, &seq);
888 while (1) {
889 unsigned int avail;
890 const u8 *ptr;
891
892 avail = skb_seq_read(consumed, &ptr, &seq);
893 if (avail == 0) {
894 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
895 consumed);
896 *status = ISCSI_TCP_SKB_DONE;
897 skb_abort_seq_read(&seq);
898 goto skb_done;
899 }
900 BUG_ON(segment->copied >= segment->size);
901
902 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
903 avail);
904 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
905 BUG_ON(rc == 0);
906 consumed += rc;
907
908 if (segment->total_copied >= segment->total_size) {
909 skb_abort_seq_read(&seq);
910 goto segment_done;
911 }
912 }
913
914segment_done:
915 *status = ISCSI_TCP_SEGMENT_DONE;
916 ISCSI_DBG_TCP(conn, "segment done\n");
917 rc = segment->done(tcp_conn, segment);
918 if (rc != 0) {
919 *status = ISCSI_TCP_CONN_ERR;
920 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
921 iscsi_conn_failure(conn, rc);
922 return 0;
923 }
924 /* The done() functions sets up the next segment. */
925
926skb_done:
927 conn->rxdata_octets += consumed;
928 return consumed;
929}
930EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
931
932/**
933 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
934 * @conn: iscsi connection
935 * @task: scsi command task
936 * @sc: scsi command
937 */
938int iscsi_tcp_task_init(struct iscsi_task *task)
939{
940 struct iscsi_tcp_task *tcp_task = task->dd_data;
941 struct iscsi_conn *conn = task->conn;
942 struct scsi_cmnd *sc = task->sc;
943 int err;
944
945 if (!sc) {
946 /*
947 * mgmt tasks do not have a scatterlist since they come
948 * in from the iscsi interface.
949 */
950 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
951
952 return conn->session->tt->init_pdu(task, 0, task->data_count);
953 }
954
955 BUG_ON(kfifo_len(&tcp_task->r2tqueue));
956 tcp_task->exp_datasn = 0;
957
958 /* Prepare PDU, optionally w/ immediate data */
959 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
960 task->itt, task->imm_count, task->unsol_r2t.data_length);
961
962 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
963 if (err)
964 return err;
965 task->imm_count = 0;
966 return 0;
967}
968EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
969
970static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
971{
972 struct iscsi_session *session = task->conn->session;
973 struct iscsi_tcp_task *tcp_task = task->dd_data;
974 struct iscsi_r2t_info *r2t = NULL;
975
976 if (iscsi_task_has_unsol_data(task))
977 r2t = &task->unsol_r2t;
978 else {
979 spin_lock_bh(&session->lock);
980 if (tcp_task->r2t) {
981 r2t = tcp_task->r2t;
982 /* Continue with this R2T? */
983 if (r2t->data_length <= r2t->sent) {
984 ISCSI_DBG_TCP(task->conn,
985 " done with r2t %p\n", r2t);
986 kfifo_in(&tcp_task->r2tpool.queue,
987 (void *)&tcp_task->r2t,
988 sizeof(void *));
989 tcp_task->r2t = r2t = NULL;
990 }
991 }
992
993 if (r2t == NULL) {
994 if (kfifo_out(&tcp_task->r2tqueue,
995 (void *)&tcp_task->r2t, sizeof(void *)) !=
996 sizeof(void *))
997 r2t = NULL;
998 else
999 r2t = tcp_task->r2t;
1000 }
1001 spin_unlock_bh(&session->lock);
1002 }
1003
1004 return r2t;
1005}
1006
1007/**
1008 * iscsi_tcp_task_xmit - xmit normal PDU task
1009 * @task: iscsi command task
1010 *
1011 * We're expected to return 0 when everything was transmitted successfully,
1012 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1013 * of error.
1014 */
1015int iscsi_tcp_task_xmit(struct iscsi_task *task)
1016{
1017 struct iscsi_conn *conn = task->conn;
1018 struct iscsi_session *session = conn->session;
1019 struct iscsi_r2t_info *r2t;
1020 int rc = 0;
1021
1022flush:
1023 /* Flush any pending data first. */
1024 rc = session->tt->xmit_pdu(task);
1025 if (rc < 0)
1026 return rc;
1027
1028 /* mgmt command */
1029 if (!task->sc) {
1030 if (task->hdr->itt == RESERVED_ITT)
1031 iscsi_put_task(task);
1032 return 0;
1033 }
1034
1035 /* Are we done already? */
1036 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1037 return 0;
1038
1039 r2t = iscsi_tcp_get_curr_r2t(task);
1040 if (r2t == NULL) {
1041 /* Waiting for more R2Ts to arrive. */
1042 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1043 return 0;
1044 }
1045
1046 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1047 if (rc)
1048 return rc;
1049 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1050
1051 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1052 r2t, r2t->datasn - 1, task->hdr->itt,
1053 r2t->data_offset + r2t->sent, r2t->data_count);
1054
1055 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1056 r2t->data_count);
1057 if (rc) {
1058 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1059 return rc;
1060 }
1061
1062 r2t->sent += r2t->data_count;
1063 goto flush;
1064}
1065EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1066
1067struct iscsi_cls_conn *
1068iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1069 uint32_t conn_idx)
1070
1071{
1072 struct iscsi_conn *conn;
1073 struct iscsi_cls_conn *cls_conn;
1074 struct iscsi_tcp_conn *tcp_conn;
1075
1076 cls_conn = iscsi_conn_setup(cls_session, sizeof(*tcp_conn), conn_idx);
1077 if (!cls_conn)
1078 return NULL;
1079 conn = cls_conn->dd_data;
1080 /*
1081 * due to strange issues with iser these are not set
1082 * in iscsi_conn_setup
1083 */
1084 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1085
1086 tcp_conn = conn->dd_data;
1087 tcp_conn->iscsi_conn = conn;
1088
1089 tcp_conn->dd_data = kzalloc(dd_data_size, GFP_KERNEL);
1090 if (!tcp_conn->dd_data) {
1091 iscsi_conn_teardown(cls_conn);
1092 return NULL;
1093 }
1094 return cls_conn;
1095}
1096EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1097
1098void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1099{
1100 struct iscsi_conn *conn = cls_conn->dd_data;
1101 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1102
1103 kfree(tcp_conn->dd_data);
1104 iscsi_conn_teardown(cls_conn);
1105}
1106EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1107
1108int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1109{
1110 int i;
1111 int cmd_i;
1112
1113 /*
1114 * initialize per-task: R2T pool and xmit queue
1115 */
1116 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1117 struct iscsi_task *task = session->cmds[cmd_i];
1118 struct iscsi_tcp_task *tcp_task = task->dd_data;
1119
1120 /*
1121 * pre-allocated x2 as much r2ts to handle race when
1122 * target acks DataOut faster than we data_xmit() queues
1123 * could replenish r2tqueue.
1124 */
1125
1126 /* R2T pool */
1127 if (iscsi_pool_init(&tcp_task->r2tpool,
1128 session->max_r2t * 2, NULL,
1129 sizeof(struct iscsi_r2t_info))) {
1130 goto r2t_alloc_fail;
1131 }
1132
1133 /* R2T xmit queue */
1134 if (kfifo_alloc(&tcp_task->r2tqueue,
1135 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1136 iscsi_pool_free(&tcp_task->r2tpool);
1137 goto r2t_alloc_fail;
1138 }
1139 }
1140
1141 return 0;
1142
1143r2t_alloc_fail:
1144 for (i = 0; i < cmd_i; i++) {
1145 struct iscsi_task *task = session->cmds[i];
1146 struct iscsi_tcp_task *tcp_task = task->dd_data;
1147
1148 kfifo_free(&tcp_task->r2tqueue);
1149 iscsi_pool_free(&tcp_task->r2tpool);
1150 }
1151 return -ENOMEM;
1152}
1153EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1154
1155void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1156{
1157 int i;
1158
1159 for (i = 0; i < session->cmds_max; i++) {
1160 struct iscsi_task *task = session->cmds[i];
1161 struct iscsi_tcp_task *tcp_task = task->dd_data;
1162
1163 kfifo_free(&tcp_task->r2tqueue);
1164 iscsi_pool_free(&tcp_task->r2tpool);
1165 }
1166}
1167EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1168
1169void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1170 struct iscsi_stats *stats)
1171{
1172 struct iscsi_conn *conn = cls_conn->dd_data;
1173
1174 stats->txdata_octets = conn->txdata_octets;
1175 stats->rxdata_octets = conn->rxdata_octets;
1176 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1177 stats->dataout_pdus = conn->dataout_pdus_cnt;
1178 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1179 stats->datain_pdus = conn->datain_pdus_cnt;
1180 stats->r2t_pdus = conn->r2t_pdus_cnt;
1181 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1182 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1183}
1184EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);