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Mike Christiea081c132008-12-02 00:32:11 -06001/*
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/file.h>
33#include <linux/blkdev.h>
34#include <linux/crypto.h>
35#include <linux/delay.h>
36#include <linux/kfifo.h>
37#include <linux/scatterlist.h>
38#include <net/tcp.h>
39#include <scsi/scsi_cmnd.h>
40#include <scsi/scsi_device.h>
41#include <scsi/scsi_host.h>
42#include <scsi/scsi.h>
43#include <scsi/scsi_transport_iscsi.h>
44
45#include "iscsi_tcp.h"
46
47MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
48 "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
49 "Alex Aizman <itn780@yahoo.com>");
50MODULE_DESCRIPTION("iSCSI/TCP data-path");
51MODULE_LICENSE("GPL");
52#undef DEBUG_TCP
53
54#ifdef DEBUG_TCP
55#define debug_tcp(fmt...) printk(KERN_INFO "tcp: " fmt)
56#else
57#define debug_tcp(fmt...)
58#endif
59
60static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
61 struct iscsi_segment *segment);
62
63/*
64 * Scatterlist handling: inside the iscsi_segment, we
65 * remember an index into the scatterlist, and set data/size
66 * to the current scatterlist entry. For highmem pages, we
67 * kmap as needed.
68 *
69 * Note that the page is unmapped when we return from
70 * TCP's data_ready handler, so we may end up mapping and
71 * unmapping the same page repeatedly. The whole reason
72 * for this is that we shouldn't keep the page mapped
73 * outside the softirq.
74 */
75
76/**
77 * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
78 * @segment: the buffer object
79 * @sg: scatterlist
80 * @offset: byte offset into that sg entry
81 *
82 * This function sets up the segment so that subsequent
83 * data is copied to the indicated sg entry, at the given
84 * offset.
85 */
86static inline void
87iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
88 struct scatterlist *sg, unsigned int offset)
89{
90 segment->sg = sg;
91 segment->sg_offset = offset;
92 segment->size = min(sg->length - offset,
93 segment->total_size - segment->total_copied);
94 segment->data = NULL;
95}
96
97/**
98 * iscsi_tcp_segment_map - map the current S/G page
99 * @segment: iscsi_segment
100 * @recv: 1 if called from recv path
101 *
102 * We only need to possibly kmap data if scatter lists are being used,
103 * because the iscsi passthrough and internal IO paths will never use high
104 * mem pages.
105 */
106static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
107{
108 struct scatterlist *sg;
109
110 if (segment->data != NULL || !segment->sg)
111 return;
112
113 sg = segment->sg;
114 BUG_ON(segment->sg_mapped);
115 BUG_ON(sg->length == 0);
116
117 /*
118 * If the page count is greater than one it is ok to send
119 * to the network layer's zero copy send path. If not we
120 * have to go the slow sendmsg path. We always map for the
121 * recv path.
122 */
123 if (page_count(sg_page(sg)) >= 1 && !recv)
124 return;
125
126 debug_tcp("iscsi_tcp_segment_map %s %p\n", recv ? "recv" : "xmit",
127 segment);
128 segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
129 segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
130}
131
132void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
133{
134 debug_tcp("iscsi_tcp_segment_unmap %p\n", segment);
135
136 if (segment->sg_mapped) {
137 debug_tcp("iscsi_tcp_segment_unmap valid\n");
138 kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
139 segment->sg_mapped = NULL;
140 segment->data = NULL;
141 }
142}
143EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
144
145/*
146 * Splice the digest buffer into the buffer
147 */
148static inline void
149iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
150{
151 segment->data = digest;
152 segment->digest_len = ISCSI_DIGEST_SIZE;
153 segment->total_size += ISCSI_DIGEST_SIZE;
154 segment->size = ISCSI_DIGEST_SIZE;
155 segment->copied = 0;
156 segment->sg = NULL;
157 segment->hash = NULL;
158}
159
160/**
161 * iscsi_tcp_segment_done - check whether the segment is complete
Mike Christie6df19a72008-12-02 00:32:16 -0600162 * @tcp_conn: iscsi tcp connection
Mike Christiea081c132008-12-02 00:32:11 -0600163 * @segment: iscsi segment to check
164 * @recv: set to one of this is called from the recv path
165 * @copied: number of bytes copied
166 *
167 * Check if we're done receiving this segment. If the receive
168 * buffer is full but we expect more data, move on to the
169 * next entry in the scatterlist.
170 *
171 * If the amount of data we received isn't a multiple of 4,
172 * we will transparently receive the pad bytes, too.
173 *
174 * This function must be re-entrant.
175 */
Mike Christie6df19a72008-12-02 00:32:16 -0600176int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
177 struct iscsi_segment *segment, int recv,
Mike Christiea081c132008-12-02 00:32:11 -0600178 unsigned copied)
179{
Mike Christiea081c132008-12-02 00:32:11 -0600180 struct scatterlist sg;
181 unsigned int pad;
182
183 debug_tcp("copied %u %u size %u %s\n", segment->copied, copied,
184 segment->size, recv ? "recv" : "xmit");
185 if (segment->hash && copied) {
186 /*
187 * If a segment is kmapd we must unmap it before sending
188 * to the crypto layer since that will try to kmap it again.
189 */
190 iscsi_tcp_segment_unmap(segment);
191
192 if (!segment->data) {
193 sg_init_table(&sg, 1);
194 sg_set_page(&sg, sg_page(segment->sg), copied,
195 segment->copied + segment->sg_offset +
196 segment->sg->offset);
197 } else
198 sg_init_one(&sg, segment->data + segment->copied,
199 copied);
200 crypto_hash_update(segment->hash, &sg, copied);
201 }
202
203 segment->copied += copied;
204 if (segment->copied < segment->size) {
205 iscsi_tcp_segment_map(segment, recv);
206 return 0;
207 }
208
209 segment->total_copied += segment->copied;
210 segment->copied = 0;
211 segment->size = 0;
212
213 /* Unmap the current scatterlist page, if there is one. */
214 iscsi_tcp_segment_unmap(segment);
215
216 /* Do we have more scatterlist entries? */
217 debug_tcp("total copied %u total size %u\n", segment->total_copied,
218 segment->total_size);
219 if (segment->total_copied < segment->total_size) {
220 /* Proceed to the next entry in the scatterlist. */
221 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
222 0);
223 iscsi_tcp_segment_map(segment, recv);
224 BUG_ON(segment->size == 0);
225 return 0;
226 }
227
228 /* Do we need to handle padding? */
Mike Christie6df19a72008-12-02 00:32:16 -0600229 if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
230 pad = iscsi_padding(segment->total_copied);
231 if (pad != 0) {
232 debug_tcp("consume %d pad bytes\n", pad);
233 segment->total_size += pad;
234 segment->size = pad;
Karen Xie28568302009-01-10 19:06:07 -0800235 segment->data = segment->padbuf;
Mike Christie6df19a72008-12-02 00:32:16 -0600236 return 0;
237 }
Mike Christiea081c132008-12-02 00:32:11 -0600238 }
239
240 /*
241 * Set us up for transferring the data digest. hdr digest
242 * is completely handled in hdr done function.
243 */
244 if (segment->hash) {
245 crypto_hash_final(segment->hash, segment->digest);
246 iscsi_tcp_segment_splice_digest(segment,
247 recv ? segment->recv_digest : segment->digest);
248 return 0;
249 }
250
251 return 1;
252}
253EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
254
255/**
256 * iscsi_tcp_segment_recv - copy data to segment
257 * @tcp_conn: the iSCSI TCP connection
258 * @segment: the buffer to copy to
259 * @ptr: data pointer
260 * @len: amount of data available
261 *
262 * This function copies up to @len bytes to the
263 * given buffer, and returns the number of bytes
264 * consumed, which can actually be less than @len.
265 *
266 * If hash digest is enabled, the function will update the
267 * hash while copying.
268 * Combining these two operations doesn't buy us a lot (yet),
269 * but in the future we could implement combined copy+crc,
270 * just way we do for network layer checksums.
271 */
272static int
273iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
274 struct iscsi_segment *segment, const void *ptr,
275 unsigned int len)
276{
277 unsigned int copy = 0, copied = 0;
278
Mike Christie6df19a72008-12-02 00:32:16 -0600279 while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
Mike Christiea081c132008-12-02 00:32:11 -0600280 if (copied == len) {
281 debug_tcp("iscsi_tcp_segment_recv copied %d bytes\n",
282 len);
283 break;
284 }
285
286 copy = min(len - copied, segment->size - segment->copied);
287 debug_tcp("iscsi_tcp_segment_recv copying %d\n", copy);
288 memcpy(segment->data + segment->copied, ptr + copied, copy);
289 copied += copy;
290 }
291 return copied;
292}
293
294inline void
295iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
296 unsigned char digest[ISCSI_DIGEST_SIZE])
297{
298 struct scatterlist sg;
299
300 sg_init_one(&sg, hdr, hdrlen);
301 crypto_hash_digest(hash, &sg, hdrlen, digest);
302}
303EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
304
305static inline int
306iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
307 struct iscsi_segment *segment)
308{
309 if (!segment->digest_len)
310 return 1;
311
312 if (memcmp(segment->recv_digest, segment->digest,
313 segment->digest_len)) {
314 debug_scsi("digest mismatch\n");
315 return 0;
316 }
317
318 return 1;
319}
320
321/*
322 * Helper function to set up segment buffer
323 */
324static inline void
325__iscsi_segment_init(struct iscsi_segment *segment, size_t size,
326 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
327{
328 memset(segment, 0, sizeof(*segment));
329 segment->total_size = size;
330 segment->done = done;
331
332 if (hash) {
333 segment->hash = hash;
334 crypto_hash_init(hash);
335 }
336}
337
338inline void
339iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
340 size_t size, iscsi_segment_done_fn_t *done,
341 struct hash_desc *hash)
342{
343 __iscsi_segment_init(segment, size, done, hash);
344 segment->data = data;
345 segment->size = size;
346}
347EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
348
349inline int
350iscsi_segment_seek_sg(struct iscsi_segment *segment,
351 struct scatterlist *sg_list, unsigned int sg_count,
352 unsigned int offset, size_t size,
353 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
354{
355 struct scatterlist *sg;
356 unsigned int i;
357
358 debug_scsi("iscsi_segment_seek_sg offset %u size %llu\n",
359 offset, size);
360 __iscsi_segment_init(segment, size, done, hash);
361 for_each_sg(sg_list, sg, sg_count, i) {
362 debug_scsi("sg %d, len %u offset %u\n", i, sg->length,
363 sg->offset);
364 if (offset < sg->length) {
365 iscsi_tcp_segment_init_sg(segment, sg, offset);
366 return 0;
367 }
368 offset -= sg->length;
369 }
370
371 return ISCSI_ERR_DATA_OFFSET;
372}
373EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
374
375/**
376 * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
377 * @tcp_conn: iscsi connection to prep for
378 *
379 * This function always passes NULL for the hash argument, because when this
380 * function is called we do not yet know the final size of the header and want
381 * to delay the digest processing until we know that.
382 */
383void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
384{
385 debug_tcp("iscsi_tcp_hdr_recv_prep(%p%s)\n", tcp_conn,
386 tcp_conn->iscsi_conn->hdrdgst_en ? ", digest enabled" : "");
387 iscsi_segment_init_linear(&tcp_conn->in.segment,
388 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
389 iscsi_tcp_hdr_recv_done, NULL);
390}
391EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
392
393/*
394 * Handle incoming reply to any other type of command
395 */
396static int
397iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
398 struct iscsi_segment *segment)
399{
400 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
401 int rc = 0;
402
403 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
404 return ISCSI_ERR_DATA_DGST;
405
406 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
407 conn->data, tcp_conn->in.datalen);
408 if (rc)
409 return rc;
410
411 iscsi_tcp_hdr_recv_prep(tcp_conn);
412 return 0;
413}
414
415static void
416iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
417{
418 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
419 struct hash_desc *rx_hash = NULL;
420
421 if (conn->datadgst_en &
422 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
423 rx_hash = tcp_conn->rx_hash;
424
425 iscsi_segment_init_linear(&tcp_conn->in.segment,
426 conn->data, tcp_conn->in.datalen,
427 iscsi_tcp_data_recv_done, rx_hash);
428}
429
430/**
431 * iscsi_tcp_cleanup_task - free tcp_task resources
432 * @task: iscsi task
433 *
434 * must be called with session lock
435 */
436void iscsi_tcp_cleanup_task(struct iscsi_task *task)
437{
438 struct iscsi_tcp_task *tcp_task = task->dd_data;
439 struct iscsi_r2t_info *r2t;
440
441 /* nothing to do for mgmt or pending tasks */
442 if (!task->sc || task->state == ISCSI_TASK_PENDING)
443 return;
444
445 /* flush task's r2t queues */
446 while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
447 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
448 sizeof(void*));
449 debug_scsi("iscsi_tcp_cleanup_task pending r2t dropped\n");
450 }
451
452 r2t = tcp_task->r2t;
453 if (r2t != NULL) {
454 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
455 sizeof(void*));
456 tcp_task->r2t = NULL;
457 }
458}
459EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
460
461/**
462 * iscsi_tcp_data_in - SCSI Data-In Response processing
463 * @conn: iscsi connection
464 * @task: scsi command task
465 */
466static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
467{
468 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
469 struct iscsi_tcp_task *tcp_task = task->dd_data;
470 struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
471 int datasn = be32_to_cpu(rhdr->datasn);
472 unsigned total_in_length = scsi_in(task->sc)->length;
473
474 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
475 if (tcp_conn->in.datalen == 0)
476 return 0;
477
478 if (tcp_task->exp_datasn != datasn) {
479 debug_tcp("%s: task->exp_datasn(%d) != rhdr->datasn(%d)\n",
480 __func__, tcp_task->exp_datasn, datasn);
481 return ISCSI_ERR_DATASN;
482 }
483
484 tcp_task->exp_datasn++;
485
486 tcp_task->data_offset = be32_to_cpu(rhdr->offset);
487 if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
488 debug_tcp("%s: data_offset(%d) + data_len(%d) > total_length_in(%d)\n",
489 __func__, tcp_task->data_offset,
490 tcp_conn->in.datalen, total_in_length);
491 return ISCSI_ERR_DATA_OFFSET;
492 }
493
494 conn->datain_pdus_cnt++;
495 return 0;
496}
497
498/**
499 * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
500 * @conn: iscsi connection
501 * @task: scsi command task
502 */
503static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
504{
505 struct iscsi_session *session = conn->session;
506 struct iscsi_tcp_task *tcp_task = task->dd_data;
507 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
508 struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
509 struct iscsi_r2t_info *r2t;
510 int r2tsn = be32_to_cpu(rhdr->r2tsn);
511 int rc;
512
513 if (tcp_conn->in.datalen) {
514 iscsi_conn_printk(KERN_ERR, conn,
515 "invalid R2t with datalen %d\n",
516 tcp_conn->in.datalen);
517 return ISCSI_ERR_DATALEN;
518 }
519
520 if (tcp_task->exp_datasn != r2tsn){
521 debug_tcp("%s: task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
522 __func__, tcp_task->exp_datasn, r2tsn);
523 return ISCSI_ERR_R2TSN;
524 }
525
526 /* fill-in new R2T associated with the task */
527 iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
528
529 if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
530 iscsi_conn_printk(KERN_INFO, conn,
531 "dropping R2T itt %d in recovery.\n",
532 task->itt);
533 return 0;
534 }
535
536 rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
537 if (!rc) {
538 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
539 "Target has sent more R2Ts than it "
540 "negotiated for or driver has has leaked.\n");
541 return ISCSI_ERR_PROTO;
542 }
543
544 r2t->exp_statsn = rhdr->statsn;
545 r2t->data_length = be32_to_cpu(rhdr->data_length);
546 if (r2t->data_length == 0) {
547 iscsi_conn_printk(KERN_ERR, conn,
548 "invalid R2T with zero data len\n");
549 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
550 sizeof(void*));
551 return ISCSI_ERR_DATALEN;
552 }
553
554 if (r2t->data_length > session->max_burst)
555 debug_scsi("invalid R2T with data len %u and max burst %u."
556 "Attempting to execute request.\n",
557 r2t->data_length, session->max_burst);
558
559 r2t->data_offset = be32_to_cpu(rhdr->data_offset);
560 if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
561 iscsi_conn_printk(KERN_ERR, conn,
562 "invalid R2T with data len %u at offset %u "
563 "and total length %d\n", r2t->data_length,
564 r2t->data_offset, scsi_out(task->sc)->length);
565 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
566 sizeof(void*));
567 return ISCSI_ERR_DATALEN;
568 }
569
570 r2t->ttt = rhdr->ttt; /* no flip */
571 r2t->datasn = 0;
572 r2t->sent = 0;
573
574 tcp_task->exp_datasn = r2tsn + 1;
575 __kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
576 conn->r2t_pdus_cnt++;
577
578 iscsi_requeue_task(task);
579 return 0;
580}
581
582/*
583 * Handle incoming reply to DataIn command
584 */
585static int
586iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
587 struct iscsi_segment *segment)
588{
589 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
590 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
591 int rc;
592
593 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
594 return ISCSI_ERR_DATA_DGST;
595
596 /* check for non-exceptional status */
597 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
598 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
599 if (rc)
600 return rc;
601 }
602
603 iscsi_tcp_hdr_recv_prep(tcp_conn);
604 return 0;
605}
606
607/**
608 * iscsi_tcp_hdr_dissect - process PDU header
609 * @conn: iSCSI connection
610 * @hdr: PDU header
611 *
612 * This function analyzes the header of the PDU received,
613 * and performs several sanity checks. If the PDU is accompanied
614 * by data, the receive buffer is set up to copy the incoming data
615 * to the correct location.
616 */
617static int
618iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
619{
620 int rc = 0, opcode, ahslen;
621 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
622 struct iscsi_task *task;
623
624 /* verify PDU length */
625 tcp_conn->in.datalen = ntoh24(hdr->dlength);
626 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
627 iscsi_conn_printk(KERN_ERR, conn,
628 "iscsi_tcp: datalen %d > %d\n",
629 tcp_conn->in.datalen, conn->max_recv_dlength);
630 return ISCSI_ERR_DATALEN;
631 }
632
633 /* Additional header segments. So far, we don't
634 * process additional headers.
635 */
636 ahslen = hdr->hlength << 2;
637
638 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
639 /* verify itt (itt encoding: age+cid+itt) */
640 rc = iscsi_verify_itt(conn, hdr->itt);
641 if (rc)
642 return rc;
643
644 debug_tcp("opcode 0x%x ahslen %d datalen %d\n",
645 opcode, ahslen, tcp_conn->in.datalen);
646
647 switch(opcode) {
648 case ISCSI_OP_SCSI_DATA_IN:
649 spin_lock(&conn->session->lock);
650 task = iscsi_itt_to_ctask(conn, hdr->itt);
651 if (!task)
652 rc = ISCSI_ERR_BAD_ITT;
653 else
654 rc = iscsi_tcp_data_in(conn, task);
655 if (rc) {
656 spin_unlock(&conn->session->lock);
657 break;
658 }
659
660 if (tcp_conn->in.datalen) {
661 struct iscsi_tcp_task *tcp_task = task->dd_data;
662 struct hash_desc *rx_hash = NULL;
663 struct scsi_data_buffer *sdb = scsi_in(task->sc);
664
665 /*
666 * Setup copy of Data-In into the Scsi_Cmnd
667 * Scatterlist case:
668 * We set up the iscsi_segment to point to the next
669 * scatterlist entry to copy to. As we go along,
670 * we move on to the next scatterlist entry and
671 * update the digest per-entry.
672 */
673 if (conn->datadgst_en &&
674 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
675 rx_hash = tcp_conn->rx_hash;
676
677 debug_tcp("iscsi_tcp_begin_data_in(%p, offset=%d, "
678 "datalen=%d)\n", tcp_conn,
679 tcp_task->data_offset,
680 tcp_conn->in.datalen);
681 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
682 sdb->table.sgl,
683 sdb->table.nents,
684 tcp_task->data_offset,
685 tcp_conn->in.datalen,
686 iscsi_tcp_process_data_in,
687 rx_hash);
688 spin_unlock(&conn->session->lock);
689 return rc;
690 }
691 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
692 spin_unlock(&conn->session->lock);
693 break;
694 case ISCSI_OP_SCSI_CMD_RSP:
695 if (tcp_conn->in.datalen) {
696 iscsi_tcp_data_recv_prep(tcp_conn);
697 return 0;
698 }
699 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
700 break;
701 case ISCSI_OP_R2T:
702 spin_lock(&conn->session->lock);
703 task = iscsi_itt_to_ctask(conn, hdr->itt);
704 if (!task)
705 rc = ISCSI_ERR_BAD_ITT;
706 else if (ahslen)
707 rc = ISCSI_ERR_AHSLEN;
708 else if (task->sc->sc_data_direction == DMA_TO_DEVICE)
709 rc = iscsi_tcp_r2t_rsp(conn, task);
710 else
711 rc = ISCSI_ERR_PROTO;
712 spin_unlock(&conn->session->lock);
713 break;
714 case ISCSI_OP_LOGIN_RSP:
715 case ISCSI_OP_TEXT_RSP:
716 case ISCSI_OP_REJECT:
717 case ISCSI_OP_ASYNC_EVENT:
718 /*
719 * It is possible that we could get a PDU with a buffer larger
720 * than 8K, but there are no targets that currently do this.
721 * For now we fail until we find a vendor that needs it
722 */
723 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
724 iscsi_conn_printk(KERN_ERR, conn,
725 "iscsi_tcp: received buffer of "
726 "len %u but conn buffer is only %u "
727 "(opcode %0x)\n",
728 tcp_conn->in.datalen,
729 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
730 rc = ISCSI_ERR_PROTO;
731 break;
732 }
733
734 /* If there's data coming in with the response,
735 * receive it to the connection's buffer.
736 */
737 if (tcp_conn->in.datalen) {
738 iscsi_tcp_data_recv_prep(tcp_conn);
739 return 0;
740 }
741 /* fall through */
742 case ISCSI_OP_LOGOUT_RSP:
743 case ISCSI_OP_NOOP_IN:
744 case ISCSI_OP_SCSI_TMFUNC_RSP:
745 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
746 break;
747 default:
748 rc = ISCSI_ERR_BAD_OPCODE;
749 break;
750 }
751
752 if (rc == 0) {
753 /* Anything that comes with data should have
754 * been handled above. */
755 if (tcp_conn->in.datalen)
756 return ISCSI_ERR_PROTO;
757 iscsi_tcp_hdr_recv_prep(tcp_conn);
758 }
759
760 return rc;
761}
762
763/**
764 * iscsi_tcp_hdr_recv_done - process PDU header
765 *
766 * This is the callback invoked when the PDU header has
767 * been received. If the header is followed by additional
768 * header segments, we go back for more data.
769 */
770static int
771iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
772 struct iscsi_segment *segment)
773{
774 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
775 struct iscsi_hdr *hdr;
776
777 /* Check if there are additional header segments
778 * *prior* to computing the digest, because we
779 * may need to go back to the caller for more.
780 */
781 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
782 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
783 /* Bump the header length - the caller will
784 * just loop around and get the AHS for us, and
785 * call again. */
786 unsigned int ahslen = hdr->hlength << 2;
787
788 /* Make sure we don't overflow */
789 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
790 return ISCSI_ERR_AHSLEN;
791
792 segment->total_size += ahslen;
793 segment->size += ahslen;
794 return 0;
795 }
796
797 /* We're done processing the header. See if we're doing
798 * header digests; if so, set up the recv_digest buffer
799 * and go back for more. */
Mike Christie6df19a72008-12-02 00:32:16 -0600800 if (conn->hdrdgst_en &&
801 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
Mike Christiea081c132008-12-02 00:32:11 -0600802 if (segment->digest_len == 0) {
803 /*
804 * Even if we offload the digest processing we
805 * splice it in so we can increment the skb/segment
806 * counters in preparation for the data segment.
807 */
808 iscsi_tcp_segment_splice_digest(segment,
809 segment->recv_digest);
810 return 0;
811 }
812
Mike Christie6df19a72008-12-02 00:32:16 -0600813 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
814 segment->total_copied - ISCSI_DIGEST_SIZE,
815 segment->digest);
Mike Christiea081c132008-12-02 00:32:11 -0600816
Mike Christie6df19a72008-12-02 00:32:16 -0600817 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
818 return ISCSI_ERR_HDR_DGST;
Mike Christiea081c132008-12-02 00:32:11 -0600819 }
820
821 tcp_conn->in.hdr = hdr;
822 return iscsi_tcp_hdr_dissect(conn, hdr);
823}
824
825/**
826 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
827 * @tcp_conn: iscsi tcp conn
828 *
829 * returns non zero if we are currently processing or setup to process
830 * a header.
831 */
832inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
833{
834 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
835}
836EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
837
838/**
839 * iscsi_tcp_recv_skb - Process skb
840 * @conn: iscsi connection
841 * @skb: network buffer with header and/or data segment
842 * @offset: offset in skb
843 * @offload: bool indicating if transfer was offloaded
844 *
845 * Will return status of transfer in status. And will return
846 * number of bytes copied.
847 */
848int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
849 unsigned int offset, bool offloaded, int *status)
850{
851 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
852 struct iscsi_segment *segment = &tcp_conn->in.segment;
853 struct skb_seq_state seq;
854 unsigned int consumed = 0;
855 int rc = 0;
856
857 debug_tcp("in %d bytes\n", skb->len - offset);
858
859 if (unlikely(conn->suspend_rx)) {
860 debug_tcp("conn %d Rx suspended!\n", conn->id);
861 *status = ISCSI_TCP_SUSPENDED;
862 return 0;
863 }
864
865 if (offloaded) {
866 segment->total_copied = segment->total_size;
867 goto segment_done;
868 }
869
870 skb_prepare_seq_read(skb, offset, skb->len, &seq);
871 while (1) {
872 unsigned int avail;
873 const u8 *ptr;
874
875 avail = skb_seq_read(consumed, &ptr, &seq);
876 if (avail == 0) {
877 debug_tcp("no more data avail. Consumed %d\n",
878 consumed);
879 *status = ISCSI_TCP_SKB_DONE;
880 skb_abort_seq_read(&seq);
881 goto skb_done;
882 }
883 BUG_ON(segment->copied >= segment->size);
884
885 debug_tcp("skb %p ptr=%p avail=%u\n", skb, ptr, avail);
886 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
887 BUG_ON(rc == 0);
888 consumed += rc;
889
890 if (segment->total_copied >= segment->total_size) {
891 skb_abort_seq_read(&seq);
892 goto segment_done;
893 }
894 }
895
896segment_done:
897 *status = ISCSI_TCP_SEGMENT_DONE;
898 debug_tcp("segment done\n");
899 rc = segment->done(tcp_conn, segment);
900 if (rc != 0) {
901 *status = ISCSI_TCP_CONN_ERR;
902 debug_tcp("Error receiving PDU, errno=%d\n", rc);
903 iscsi_conn_failure(conn, rc);
904 return 0;
905 }
906 /* The done() functions sets up the next segment. */
907
908skb_done:
909 conn->rxdata_octets += consumed;
910 return consumed;
911}
912EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
913
914/**
915 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
916 * @conn: iscsi connection
917 * @task: scsi command task
918 * @sc: scsi command
919 */
920int iscsi_tcp_task_init(struct iscsi_task *task)
921{
922 struct iscsi_tcp_task *tcp_task = task->dd_data;
923 struct iscsi_conn *conn = task->conn;
924 struct scsi_cmnd *sc = task->sc;
925 int err;
926
927 if (!sc) {
928 /*
929 * mgmt tasks do not have a scatterlist since they come
930 * in from the iscsi interface.
931 */
932 debug_scsi("mtask deq [cid %d itt 0x%x]\n", conn->id,
933 task->itt);
934
935 return conn->session->tt->init_pdu(task, 0, task->data_count);
936 }
937
938 BUG_ON(__kfifo_len(tcp_task->r2tqueue));
939 tcp_task->exp_datasn = 0;
940
941 /* Prepare PDU, optionally w/ immediate data */
942 debug_scsi("task deq [cid %d itt 0x%x imm %d unsol %d]\n",
943 conn->id, task->itt, task->imm_count,
944 task->unsol_r2t.data_length);
945
946 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
947 if (err)
948 return err;
949 task->imm_count = 0;
950 return 0;
951}
952EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
953
954static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
955{
956 struct iscsi_session *session = task->conn->session;
957 struct iscsi_tcp_task *tcp_task = task->dd_data;
958 struct iscsi_r2t_info *r2t = NULL;
959
960 if (iscsi_task_has_unsol_data(task))
961 r2t = &task->unsol_r2t;
962 else {
963 spin_lock_bh(&session->lock);
964 if (tcp_task->r2t) {
965 r2t = tcp_task->r2t;
966 /* Continue with this R2T? */
967 if (r2t->data_length <= r2t->sent) {
968 debug_scsi(" done with r2t %p\n", r2t);
969 __kfifo_put(tcp_task->r2tpool.queue,
970 (void *)&tcp_task->r2t,
971 sizeof(void *));
972 tcp_task->r2t = r2t = NULL;
973 }
974 }
975
976 if (r2t == NULL) {
977 __kfifo_get(tcp_task->r2tqueue,
978 (void *)&tcp_task->r2t, sizeof(void *));
979 r2t = tcp_task->r2t;
980 }
981 spin_unlock_bh(&session->lock);
982 }
983
984 return r2t;
985}
986
987/**
988 * iscsi_tcp_task_xmit - xmit normal PDU task
989 * @task: iscsi command task
990 *
991 * We're expected to return 0 when everything was transmitted succesfully,
992 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
993 * of error.
994 */
995int iscsi_tcp_task_xmit(struct iscsi_task *task)
996{
997 struct iscsi_conn *conn = task->conn;
998 struct iscsi_session *session = conn->session;
999 struct iscsi_r2t_info *r2t;
1000 int rc = 0;
1001
1002flush:
1003 /* Flush any pending data first. */
1004 rc = session->tt->xmit_pdu(task);
1005 if (rc < 0)
1006 return rc;
1007
1008 /* mgmt command */
1009 if (!task->sc) {
1010 if (task->hdr->itt == RESERVED_ITT)
1011 iscsi_put_task(task);
1012 return 0;
1013 }
1014
1015 /* Are we done already? */
1016 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1017 return 0;
1018
1019 r2t = iscsi_tcp_get_curr_r2t(task);
1020 if (r2t == NULL) {
1021 /* Waiting for more R2Ts to arrive. */
1022 debug_tcp("no R2Ts yet\n");
1023 return 0;
1024 }
1025
Mike Christie2ff79d52008-12-02 00:32:14 -06001026 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
Mike Christiea081c132008-12-02 00:32:11 -06001027 if (rc)
1028 return rc;
1029 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1030
1031 debug_scsi("sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1032 r2t, r2t->datasn - 1, task->hdr->itt,
1033 r2t->data_offset + r2t->sent, r2t->data_count);
1034
1035 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1036 r2t->data_count);
1037 if (rc)
1038 return rc;
1039 r2t->sent += r2t->data_count;
1040 goto flush;
1041}
1042EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1043
1044struct iscsi_cls_conn *
1045iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1046 uint32_t conn_idx)
1047
1048{
1049 struct iscsi_conn *conn;
1050 struct iscsi_cls_conn *cls_conn;
1051 struct iscsi_tcp_conn *tcp_conn;
1052
1053 cls_conn = iscsi_conn_setup(cls_session, sizeof(*tcp_conn), conn_idx);
1054 if (!cls_conn)
1055 return NULL;
1056 conn = cls_conn->dd_data;
1057 /*
1058 * due to strange issues with iser these are not set
1059 * in iscsi_conn_setup
1060 */
1061 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1062
1063 tcp_conn = conn->dd_data;
1064 tcp_conn->iscsi_conn = conn;
1065
1066 tcp_conn->dd_data = kzalloc(dd_data_size, GFP_KERNEL);
1067 if (!tcp_conn->dd_data) {
1068 iscsi_conn_teardown(cls_conn);
1069 return NULL;
1070 }
1071 return cls_conn;
1072}
1073EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1074
1075void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1076{
1077 struct iscsi_conn *conn = cls_conn->dd_data;
1078 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1079
1080 kfree(tcp_conn->dd_data);
1081 iscsi_conn_teardown(cls_conn);
1082}
1083EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1084
1085int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1086{
1087 int i;
1088 int cmd_i;
1089
1090 /*
1091 * initialize per-task: R2T pool and xmit queue
1092 */
1093 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1094 struct iscsi_task *task = session->cmds[cmd_i];
1095 struct iscsi_tcp_task *tcp_task = task->dd_data;
1096
1097 /*
1098 * pre-allocated x2 as much r2ts to handle race when
1099 * target acks DataOut faster than we data_xmit() queues
1100 * could replenish r2tqueue.
1101 */
1102
1103 /* R2T pool */
1104 if (iscsi_pool_init(&tcp_task->r2tpool,
1105 session->max_r2t * 2, NULL,
1106 sizeof(struct iscsi_r2t_info))) {
1107 goto r2t_alloc_fail;
1108 }
1109
1110 /* R2T xmit queue */
1111 tcp_task->r2tqueue = kfifo_alloc(
1112 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
1113 if (tcp_task->r2tqueue == ERR_PTR(-ENOMEM)) {
1114 iscsi_pool_free(&tcp_task->r2tpool);
1115 goto r2t_alloc_fail;
1116 }
1117 }
1118
1119 return 0;
1120
1121r2t_alloc_fail:
1122 for (i = 0; i < cmd_i; i++) {
1123 struct iscsi_task *task = session->cmds[i];
1124 struct iscsi_tcp_task *tcp_task = task->dd_data;
1125
1126 kfifo_free(tcp_task->r2tqueue);
1127 iscsi_pool_free(&tcp_task->r2tpool);
1128 }
1129 return -ENOMEM;
1130}
1131EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1132
1133void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1134{
1135 int i;
1136
1137 for (i = 0; i < session->cmds_max; i++) {
1138 struct iscsi_task *task = session->cmds[i];
1139 struct iscsi_tcp_task *tcp_task = task->dd_data;
1140
1141 kfifo_free(tcp_task->r2tqueue);
1142 iscsi_pool_free(&tcp_task->r2tpool);
1143 }
1144}
1145EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1146
1147void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1148 struct iscsi_stats *stats)
1149{
1150 struct iscsi_conn *conn = cls_conn->dd_data;
1151
1152 stats->txdata_octets = conn->txdata_octets;
1153 stats->rxdata_octets = conn->rxdata_octets;
1154 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1155 stats->dataout_pdus = conn->dataout_pdus_cnt;
1156 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1157 stats->datain_pdus = conn->datain_pdus_cnt;
1158 stats->r2t_pdus = conn->r2t_pdus_cnt;
1159 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1160 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1161}
1162EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);