1 /******************************************************************************
2  * This file contains error recovery level zero functions used by
3  * the iSCSI Target driver.
4  *
5  * \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
6  *
7  * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
8  *
9  * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  ******************************************************************************/
21 
22 #include <scsi/iscsi_proto.h>
23 #include <target/target_core_base.h>
24 #include <target/target_core_fabric.h>
25 
26 #include "iscsi_target_core.h"
27 #include "iscsi_target_seq_pdu_list.h"
28 #include "iscsi_target_tq.h"
29 #include "iscsi_target_erl0.h"
30 #include "iscsi_target_erl1.h"
31 #include "iscsi_target_erl2.h"
32 #include "iscsi_target_util.h"
33 #include "iscsi_target.h"
34 
35 /*
36  *	Used to set values in struct iscsi_cmd that iscsit_dataout_check_sequence()
37  *	checks against to determine a PDU's Offset+Length is within the current
38  *	DataOUT Sequence.  Used for DataSequenceInOrder=Yes only.
39  */
40 void iscsit_set_dataout_sequence_values(
41 	struct iscsi_cmd *cmd)
42 {
43 	struct iscsi_conn *conn = cmd->conn;
44 	/*
45 	 * Still set seq_start_offset and seq_end_offset for Unsolicited
46 	 * DataOUT, even if DataSequenceInOrder=No.
47 	 */
48 	if (cmd->unsolicited_data) {
49 		cmd->seq_start_offset = cmd->write_data_done;
50 		cmd->seq_end_offset = (cmd->write_data_done +
51 			(cmd->se_cmd.data_length >
52 			 conn->sess->sess_ops->FirstBurstLength) ?
53 			conn->sess->sess_ops->FirstBurstLength : cmd->se_cmd.data_length);
54 		return;
55 	}
56 
57 	if (!conn->sess->sess_ops->DataSequenceInOrder)
58 		return;
59 
60 	if (!cmd->seq_start_offset && !cmd->seq_end_offset) {
61 		cmd->seq_start_offset = cmd->write_data_done;
62 		cmd->seq_end_offset = (cmd->se_cmd.data_length >
63 			conn->sess->sess_ops->MaxBurstLength) ?
64 			(cmd->write_data_done +
65 			conn->sess->sess_ops->MaxBurstLength) : cmd->se_cmd.data_length;
66 	} else {
67 		cmd->seq_start_offset = cmd->seq_end_offset;
68 		cmd->seq_end_offset = ((cmd->seq_end_offset +
69 			conn->sess->sess_ops->MaxBurstLength) >=
70 			cmd->se_cmd.data_length) ? cmd->se_cmd.data_length :
71 			(cmd->seq_end_offset +
72 			 conn->sess->sess_ops->MaxBurstLength);
73 	}
74 }
75 
76 static int iscsit_dataout_within_command_recovery_check(
77 	struct iscsi_cmd *cmd,
78 	unsigned char *buf)
79 {
80 	struct iscsi_conn *conn = cmd->conn;
81 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
82 	u32 payload_length = ntoh24(hdr->dlength);
83 
84 	/*
85 	 * We do the within-command recovery checks here as it is
86 	 * the first function called in iscsi_check_pre_dataout().
87 	 * Basically, if we are in within-command recovery and
88 	 * the PDU does not contain the offset the sequence needs,
89 	 * dump the payload.
90 	 *
91 	 * This only applies to DataPDUInOrder=Yes, for
92 	 * DataPDUInOrder=No we only re-request the failed PDU
93 	 * and check that all PDUs in a sequence are received
94 	 * upon end of sequence.
95 	 */
96 	if (conn->sess->sess_ops->DataSequenceInOrder) {
97 		if ((cmd->cmd_flags & ICF_WITHIN_COMMAND_RECOVERY) &&
98 		    (cmd->write_data_done != hdr->offset))
99 			goto dump;
100 
101 		cmd->cmd_flags &= ~ICF_WITHIN_COMMAND_RECOVERY;
102 	} else {
103 		struct iscsi_seq *seq;
104 
105 		seq = iscsit_get_seq_holder(cmd, hdr->offset, payload_length);
106 		if (!seq)
107 			return DATAOUT_CANNOT_RECOVER;
108 		/*
109 		 * Set the struct iscsi_seq pointer to reuse later.
110 		 */
111 		cmd->seq_ptr = seq;
112 
113 		if (conn->sess->sess_ops->DataPDUInOrder) {
114 			if ((seq->status ==
115 			     DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY) &&
116 			   ((seq->offset != hdr->offset) ||
117 			    (seq->data_sn != hdr->datasn)))
118 				goto dump;
119 		} else {
120 			if ((seq->status ==
121 			     DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY) &&
122 			    (seq->data_sn != hdr->datasn))
123 				goto dump;
124 		}
125 
126 		if (seq->status == DATAOUT_SEQUENCE_COMPLETE)
127 			goto dump;
128 
129 		if (seq->status != DATAOUT_SEQUENCE_COMPLETE)
130 			seq->status = 0;
131 	}
132 
133 	return DATAOUT_NORMAL;
134 
135 dump:
136 	pr_err("Dumping DataOUT PDU Offset: %u Length: %d DataSN:"
137 		" 0x%08x\n", hdr->offset, payload_length, hdr->datasn);
138 	return iscsit_dump_data_payload(conn, payload_length, 1);
139 }
140 
141 static int iscsit_dataout_check_unsolicited_sequence(
142 	struct iscsi_cmd *cmd,
143 	unsigned char *buf)
144 {
145 	u32 first_burst_len;
146 	struct iscsi_conn *conn = cmd->conn;
147 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
148 	u32 payload_length = ntoh24(hdr->dlength);
149 
150 
151 	if ((hdr->offset < cmd->seq_start_offset) ||
152 	   ((hdr->offset + payload_length) > cmd->seq_end_offset)) {
153 		pr_err("Command ITT: 0x%08x with Offset: %u,"
154 		" Length: %u outside of Unsolicited Sequence %u:%u while"
155 		" DataSequenceInOrder=Yes.\n", cmd->init_task_tag,
156 		hdr->offset, payload_length, cmd->seq_start_offset,
157 			cmd->seq_end_offset);
158 		return DATAOUT_CANNOT_RECOVER;
159 	}
160 
161 	first_burst_len = (cmd->first_burst_len + payload_length);
162 
163 	if (first_burst_len > conn->sess->sess_ops->FirstBurstLength) {
164 		pr_err("Total %u bytes exceeds FirstBurstLength: %u"
165 			" for this Unsolicited DataOut Burst.\n",
166 			first_burst_len, conn->sess->sess_ops->FirstBurstLength);
167 		transport_send_check_condition_and_sense(&cmd->se_cmd,
168 				TCM_INCORRECT_AMOUNT_OF_DATA, 0);
169 		return DATAOUT_CANNOT_RECOVER;
170 	}
171 
172 	/*
173 	 * Perform various MaxBurstLength and ISCSI_FLAG_CMD_FINAL sanity
174 	 * checks for the current Unsolicited DataOUT Sequence.
175 	 */
176 	if (hdr->flags & ISCSI_FLAG_CMD_FINAL) {
177 		/*
178 		 * Ignore ISCSI_FLAG_CMD_FINAL checks while DataPDUInOrder=No, end of
179 		 * sequence checks are handled in
180 		 * iscsit_dataout_datapduinorder_no_fbit().
181 		 */
182 		if (!conn->sess->sess_ops->DataPDUInOrder)
183 			goto out;
184 
185 		if ((first_burst_len != cmd->se_cmd.data_length) &&
186 		    (first_burst_len != conn->sess->sess_ops->FirstBurstLength)) {
187 			pr_err("Unsolicited non-immediate data"
188 			" received %u does not equal FirstBurstLength: %u, and"
189 			" does not equal ExpXferLen %u.\n", first_burst_len,
190 				conn->sess->sess_ops->FirstBurstLength,
191 				cmd->se_cmd.data_length);
192 			transport_send_check_condition_and_sense(&cmd->se_cmd,
193 					TCM_INCORRECT_AMOUNT_OF_DATA, 0);
194 			return DATAOUT_CANNOT_RECOVER;
195 		}
196 	} else {
197 		if (first_burst_len == conn->sess->sess_ops->FirstBurstLength) {
198 			pr_err("Command ITT: 0x%08x reached"
199 			" FirstBurstLength: %u, but ISCSI_FLAG_CMD_FINAL is not set. protocol"
200 				" error.\n", cmd->init_task_tag,
201 				conn->sess->sess_ops->FirstBurstLength);
202 			return DATAOUT_CANNOT_RECOVER;
203 		}
204 		if (first_burst_len == cmd->se_cmd.data_length) {
205 			pr_err("Command ITT: 0x%08x reached"
206 			" ExpXferLen: %u, but ISCSI_FLAG_CMD_FINAL is not set. protocol"
207 			" error.\n", cmd->init_task_tag, cmd->se_cmd.data_length);
208 			return DATAOUT_CANNOT_RECOVER;
209 		}
210 	}
211 
212 out:
213 	return DATAOUT_NORMAL;
214 }
215 
216 static int iscsit_dataout_check_sequence(
217 	struct iscsi_cmd *cmd,
218 	unsigned char *buf)
219 {
220 	u32 next_burst_len;
221 	struct iscsi_conn *conn = cmd->conn;
222 	struct iscsi_seq *seq = NULL;
223 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
224 	u32 payload_length = ntoh24(hdr->dlength);
225 
226 	/*
227 	 * For DataSequenceInOrder=Yes: Check that the offset and offset+length
228 	 * is within range as defined by iscsi_set_dataout_sequence_values().
229 	 *
230 	 * For DataSequenceInOrder=No: Check that an struct iscsi_seq exists for
231 	 * offset+length tuple.
232 	 */
233 	if (conn->sess->sess_ops->DataSequenceInOrder) {
234 		/*
235 		 * Due to possibility of recovery DataOUT sent by the initiator
236 		 * fullfilling an Recovery R2T, it's best to just dump the
237 		 * payload here, instead of erroring out.
238 		 */
239 		if ((hdr->offset < cmd->seq_start_offset) ||
240 		   ((hdr->offset + payload_length) > cmd->seq_end_offset)) {
241 			pr_err("Command ITT: 0x%08x with Offset: %u,"
242 			" Length: %u outside of Sequence %u:%u while"
243 			" DataSequenceInOrder=Yes.\n", cmd->init_task_tag,
244 			hdr->offset, payload_length, cmd->seq_start_offset,
245 				cmd->seq_end_offset);
246 
247 			if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
248 				return DATAOUT_CANNOT_RECOVER;
249 			return DATAOUT_WITHIN_COMMAND_RECOVERY;
250 		}
251 
252 		next_burst_len = (cmd->next_burst_len + payload_length);
253 	} else {
254 		seq = iscsit_get_seq_holder(cmd, hdr->offset, payload_length);
255 		if (!seq)
256 			return DATAOUT_CANNOT_RECOVER;
257 		/*
258 		 * Set the struct iscsi_seq pointer to reuse later.
259 		 */
260 		cmd->seq_ptr = seq;
261 
262 		if (seq->status == DATAOUT_SEQUENCE_COMPLETE) {
263 			if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
264 				return DATAOUT_CANNOT_RECOVER;
265 			return DATAOUT_WITHIN_COMMAND_RECOVERY;
266 		}
267 
268 		next_burst_len = (seq->next_burst_len + payload_length);
269 	}
270 
271 	if (next_burst_len > conn->sess->sess_ops->MaxBurstLength) {
272 		pr_err("Command ITT: 0x%08x, NextBurstLength: %u and"
273 			" Length: %u exceeds MaxBurstLength: %u. protocol"
274 			" error.\n", cmd->init_task_tag,
275 			(next_burst_len - payload_length),
276 			payload_length, conn->sess->sess_ops->MaxBurstLength);
277 		return DATAOUT_CANNOT_RECOVER;
278 	}
279 
280 	/*
281 	 * Perform various MaxBurstLength and ISCSI_FLAG_CMD_FINAL sanity
282 	 * checks for the current DataOUT Sequence.
283 	 */
284 	if (hdr->flags & ISCSI_FLAG_CMD_FINAL) {
285 		/*
286 		 * Ignore ISCSI_FLAG_CMD_FINAL checks while DataPDUInOrder=No, end of
287 		 * sequence checks are handled in
288 		 * iscsit_dataout_datapduinorder_no_fbit().
289 		 */
290 		if (!conn->sess->sess_ops->DataPDUInOrder)
291 			goto out;
292 
293 		if (conn->sess->sess_ops->DataSequenceInOrder) {
294 			if ((next_burst_len <
295 			     conn->sess->sess_ops->MaxBurstLength) &&
296 			   ((cmd->write_data_done + payload_length) <
297 			     cmd->se_cmd.data_length)) {
298 				pr_err("Command ITT: 0x%08x set ISCSI_FLAG_CMD_FINAL"
299 				" before end of DataOUT sequence, protocol"
300 				" error.\n", cmd->init_task_tag);
301 				return DATAOUT_CANNOT_RECOVER;
302 			}
303 		} else {
304 			if (next_burst_len < seq->xfer_len) {
305 				pr_err("Command ITT: 0x%08x set ISCSI_FLAG_CMD_FINAL"
306 				" before end of DataOUT sequence, protocol"
307 				" error.\n", cmd->init_task_tag);
308 				return DATAOUT_CANNOT_RECOVER;
309 			}
310 		}
311 	} else {
312 		if (conn->sess->sess_ops->DataSequenceInOrder) {
313 			if (next_burst_len ==
314 					conn->sess->sess_ops->MaxBurstLength) {
315 				pr_err("Command ITT: 0x%08x reached"
316 				" MaxBurstLength: %u, but ISCSI_FLAG_CMD_FINAL is"
317 				" not set, protocol error.", cmd->init_task_tag,
318 					conn->sess->sess_ops->MaxBurstLength);
319 				return DATAOUT_CANNOT_RECOVER;
320 			}
321 			if ((cmd->write_data_done + payload_length) ==
322 					cmd->se_cmd.data_length) {
323 				pr_err("Command ITT: 0x%08x reached"
324 				" last DataOUT PDU in sequence but ISCSI_FLAG_"
325 				"CMD_FINAL is not set, protocol error.\n",
326 					cmd->init_task_tag);
327 				return DATAOUT_CANNOT_RECOVER;
328 			}
329 		} else {
330 			if (next_burst_len == seq->xfer_len) {
331 				pr_err("Command ITT: 0x%08x reached"
332 				" last DataOUT PDU in sequence but ISCSI_FLAG_"
333 				"CMD_FINAL is not set, protocol error.\n",
334 					cmd->init_task_tag);
335 				return DATAOUT_CANNOT_RECOVER;
336 			}
337 		}
338 	}
339 
340 out:
341 	return DATAOUT_NORMAL;
342 }
343 
344 static int iscsit_dataout_check_datasn(
345 	struct iscsi_cmd *cmd,
346 	unsigned char *buf)
347 {
348 	int dump = 0, recovery = 0;
349 	u32 data_sn = 0;
350 	struct iscsi_conn *conn = cmd->conn;
351 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
352 	u32 payload_length = ntoh24(hdr->dlength);
353 
354 	/*
355 	 * Considering the target has no method of re-requesting DataOUT
356 	 * by DataSN, if we receieve a greater DataSN than expected we
357 	 * assume the functions for DataPDUInOrder=[Yes,No] below will
358 	 * handle it.
359 	 *
360 	 * If the DataSN is less than expected, dump the payload.
361 	 */
362 	if (conn->sess->sess_ops->DataSequenceInOrder)
363 		data_sn = cmd->data_sn;
364 	else {
365 		struct iscsi_seq *seq = cmd->seq_ptr;
366 		data_sn = seq->data_sn;
367 	}
368 
369 	if (hdr->datasn > data_sn) {
370 		pr_err("Command ITT: 0x%08x, received DataSN: 0x%08x"
371 			" higher than expected 0x%08x.\n", cmd->init_task_tag,
372 				hdr->datasn, data_sn);
373 		recovery = 1;
374 		goto recover;
375 	} else if (hdr->datasn < data_sn) {
376 		pr_err("Command ITT: 0x%08x, received DataSN: 0x%08x"
377 			" lower than expected 0x%08x, discarding payload.\n",
378 			cmd->init_task_tag, hdr->datasn, data_sn);
379 		dump = 1;
380 		goto dump;
381 	}
382 
383 	return DATAOUT_NORMAL;
384 
385 recover:
386 	if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
387 		pr_err("Unable to perform within-command recovery"
388 				" while ERL=0.\n");
389 		return DATAOUT_CANNOT_RECOVER;
390 	}
391 dump:
392 	if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
393 		return DATAOUT_CANNOT_RECOVER;
394 
395 	return (recovery || dump) ? DATAOUT_WITHIN_COMMAND_RECOVERY :
396 				DATAOUT_NORMAL;
397 }
398 
399 static int iscsit_dataout_pre_datapduinorder_yes(
400 	struct iscsi_cmd *cmd,
401 	unsigned char *buf)
402 {
403 	int dump = 0, recovery = 0;
404 	struct iscsi_conn *conn = cmd->conn;
405 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
406 	u32 payload_length = ntoh24(hdr->dlength);
407 
408 	/*
409 	 * For DataSequenceInOrder=Yes: If the offset is greater than the global
410 	 * DataPDUInOrder=Yes offset counter in struct iscsi_cmd a protcol error has
411 	 * occured and fail the connection.
412 	 *
413 	 * For DataSequenceInOrder=No: If the offset is greater than the per
414 	 * sequence DataPDUInOrder=Yes offset counter in struct iscsi_seq a protocol
415 	 * error has occured and fail the connection.
416 	 */
417 	if (conn->sess->sess_ops->DataSequenceInOrder) {
418 		if (hdr->offset != cmd->write_data_done) {
419 			pr_err("Command ITT: 0x%08x, received offset"
420 			" %u different than expected %u.\n", cmd->init_task_tag,
421 				hdr->offset, cmd->write_data_done);
422 			recovery = 1;
423 			goto recover;
424 		}
425 	} else {
426 		struct iscsi_seq *seq = cmd->seq_ptr;
427 
428 		if (hdr->offset > seq->offset) {
429 			pr_err("Command ITT: 0x%08x, received offset"
430 			" %u greater than expected %u.\n", cmd->init_task_tag,
431 				hdr->offset, seq->offset);
432 			recovery = 1;
433 			goto recover;
434 		} else if (hdr->offset < seq->offset) {
435 			pr_err("Command ITT: 0x%08x, received offset"
436 			" %u less than expected %u, discarding payload.\n",
437 				cmd->init_task_tag, hdr->offset, seq->offset);
438 			dump = 1;
439 			goto dump;
440 		}
441 	}
442 
443 	return DATAOUT_NORMAL;
444 
445 recover:
446 	if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
447 		pr_err("Unable to perform within-command recovery"
448 				" while ERL=0.\n");
449 		return DATAOUT_CANNOT_RECOVER;
450 	}
451 dump:
452 	if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
453 		return DATAOUT_CANNOT_RECOVER;
454 
455 	return (recovery) ? iscsit_recover_dataout_sequence(cmd,
456 		hdr->offset, payload_length) :
457 	       (dump) ? DATAOUT_WITHIN_COMMAND_RECOVERY : DATAOUT_NORMAL;
458 }
459 
460 static int iscsit_dataout_pre_datapduinorder_no(
461 	struct iscsi_cmd *cmd,
462 	unsigned char *buf)
463 {
464 	struct iscsi_pdu *pdu;
465 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
466 	u32 payload_length = ntoh24(hdr->dlength);
467 
468 	pdu = iscsit_get_pdu_holder(cmd, hdr->offset, payload_length);
469 	if (!pdu)
470 		return DATAOUT_CANNOT_RECOVER;
471 
472 	cmd->pdu_ptr = pdu;
473 
474 	switch (pdu->status) {
475 	case ISCSI_PDU_NOT_RECEIVED:
476 	case ISCSI_PDU_CRC_FAILED:
477 	case ISCSI_PDU_TIMED_OUT:
478 		break;
479 	case ISCSI_PDU_RECEIVED_OK:
480 		pr_err("Command ITT: 0x%08x received already gotten"
481 			" Offset: %u, Length: %u\n", cmd->init_task_tag,
482 				hdr->offset, payload_length);
483 		return iscsit_dump_data_payload(cmd->conn, payload_length, 1);
484 	default:
485 		return DATAOUT_CANNOT_RECOVER;
486 	}
487 
488 	return DATAOUT_NORMAL;
489 }
490 
491 static int iscsit_dataout_update_r2t(struct iscsi_cmd *cmd, u32 offset, u32 length)
492 {
493 	struct iscsi_r2t *r2t;
494 
495 	if (cmd->unsolicited_data)
496 		return 0;
497 
498 	r2t = iscsit_get_r2t_for_eos(cmd, offset, length);
499 	if (!r2t)
500 		return -1;
501 
502 	spin_lock_bh(&cmd->r2t_lock);
503 	r2t->seq_complete = 1;
504 	cmd->outstanding_r2ts--;
505 	spin_unlock_bh(&cmd->r2t_lock);
506 
507 	return 0;
508 }
509 
510 static int iscsit_dataout_update_datapduinorder_no(
511 	struct iscsi_cmd *cmd,
512 	u32 data_sn,
513 	int f_bit)
514 {
515 	int ret = 0;
516 	struct iscsi_pdu *pdu = cmd->pdu_ptr;
517 
518 	pdu->data_sn = data_sn;
519 
520 	switch (pdu->status) {
521 	case ISCSI_PDU_NOT_RECEIVED:
522 		pdu->status = ISCSI_PDU_RECEIVED_OK;
523 		break;
524 	case ISCSI_PDU_CRC_FAILED:
525 		pdu->status = ISCSI_PDU_RECEIVED_OK;
526 		break;
527 	case ISCSI_PDU_TIMED_OUT:
528 		pdu->status = ISCSI_PDU_RECEIVED_OK;
529 		break;
530 	default:
531 		return DATAOUT_CANNOT_RECOVER;
532 	}
533 
534 	if (f_bit) {
535 		ret = iscsit_dataout_datapduinorder_no_fbit(cmd, pdu);
536 		if (ret == DATAOUT_CANNOT_RECOVER)
537 			return ret;
538 	}
539 
540 	return DATAOUT_NORMAL;
541 }
542 
543 static int iscsit_dataout_post_crc_passed(
544 	struct iscsi_cmd *cmd,
545 	unsigned char *buf)
546 {
547 	int ret, send_r2t = 0;
548 	struct iscsi_conn *conn = cmd->conn;
549 	struct iscsi_seq *seq = NULL;
550 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
551 	u32 payload_length = ntoh24(hdr->dlength);
552 
553 	if (cmd->unsolicited_data) {
554 		if ((cmd->first_burst_len + payload_length) ==
555 		     conn->sess->sess_ops->FirstBurstLength) {
556 			if (iscsit_dataout_update_r2t(cmd, hdr->offset,
557 					payload_length) < 0)
558 				return DATAOUT_CANNOT_RECOVER;
559 			send_r2t = 1;
560 		}
561 
562 		if (!conn->sess->sess_ops->DataPDUInOrder) {
563 			ret = iscsit_dataout_update_datapduinorder_no(cmd,
564 				hdr->datasn, (hdr->flags & ISCSI_FLAG_CMD_FINAL));
565 			if (ret == DATAOUT_CANNOT_RECOVER)
566 				return ret;
567 		}
568 
569 		cmd->first_burst_len += payload_length;
570 
571 		if (conn->sess->sess_ops->DataSequenceInOrder)
572 			cmd->data_sn++;
573 		else {
574 			seq = cmd->seq_ptr;
575 			seq->data_sn++;
576 			seq->offset += payload_length;
577 		}
578 
579 		if (send_r2t) {
580 			if (seq)
581 				seq->status = DATAOUT_SEQUENCE_COMPLETE;
582 			cmd->first_burst_len = 0;
583 			cmd->unsolicited_data = 0;
584 		}
585 	} else {
586 		if (conn->sess->sess_ops->DataSequenceInOrder) {
587 			if ((cmd->next_burst_len + payload_length) ==
588 			     conn->sess->sess_ops->MaxBurstLength) {
589 				if (iscsit_dataout_update_r2t(cmd, hdr->offset,
590 						payload_length) < 0)
591 					return DATAOUT_CANNOT_RECOVER;
592 				send_r2t = 1;
593 			}
594 
595 			if (!conn->sess->sess_ops->DataPDUInOrder) {
596 				ret = iscsit_dataout_update_datapduinorder_no(
597 						cmd, hdr->datasn,
598 						(hdr->flags & ISCSI_FLAG_CMD_FINAL));
599 				if (ret == DATAOUT_CANNOT_RECOVER)
600 					return ret;
601 			}
602 
603 			cmd->next_burst_len += payload_length;
604 			cmd->data_sn++;
605 
606 			if (send_r2t)
607 				cmd->next_burst_len = 0;
608 		} else {
609 			seq = cmd->seq_ptr;
610 
611 			if ((seq->next_burst_len + payload_length) ==
612 			     seq->xfer_len) {
613 				if (iscsit_dataout_update_r2t(cmd, hdr->offset,
614 						payload_length) < 0)
615 					return DATAOUT_CANNOT_RECOVER;
616 				send_r2t = 1;
617 			}
618 
619 			if (!conn->sess->sess_ops->DataPDUInOrder) {
620 				ret = iscsit_dataout_update_datapduinorder_no(
621 						cmd, hdr->datasn,
622 						(hdr->flags & ISCSI_FLAG_CMD_FINAL));
623 				if (ret == DATAOUT_CANNOT_RECOVER)
624 					return ret;
625 			}
626 
627 			seq->data_sn++;
628 			seq->offset += payload_length;
629 			seq->next_burst_len += payload_length;
630 
631 			if (send_r2t) {
632 				seq->next_burst_len = 0;
633 				seq->status = DATAOUT_SEQUENCE_COMPLETE;
634 			}
635 		}
636 	}
637 
638 	if (send_r2t && conn->sess->sess_ops->DataSequenceInOrder)
639 		cmd->data_sn = 0;
640 
641 	cmd->write_data_done += payload_length;
642 
643 	if (cmd->write_data_done == cmd->se_cmd.data_length)
644 		return DATAOUT_SEND_TO_TRANSPORT;
645 	else if (send_r2t)
646 		return DATAOUT_SEND_R2T;
647 	else
648 		return DATAOUT_NORMAL;
649 }
650 
651 static int iscsit_dataout_post_crc_failed(
652 	struct iscsi_cmd *cmd,
653 	unsigned char *buf)
654 {
655 	struct iscsi_conn *conn = cmd->conn;
656 	struct iscsi_pdu *pdu;
657 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
658 	u32 payload_length = ntoh24(hdr->dlength);
659 
660 	if (conn->sess->sess_ops->DataPDUInOrder)
661 		goto recover;
662 	/*
663 	 * The rest of this function is only called when DataPDUInOrder=No.
664 	 */
665 	pdu = cmd->pdu_ptr;
666 
667 	switch (pdu->status) {
668 	case ISCSI_PDU_NOT_RECEIVED:
669 		pdu->status = ISCSI_PDU_CRC_FAILED;
670 		break;
671 	case ISCSI_PDU_CRC_FAILED:
672 		break;
673 	case ISCSI_PDU_TIMED_OUT:
674 		pdu->status = ISCSI_PDU_CRC_FAILED;
675 		break;
676 	default:
677 		return DATAOUT_CANNOT_RECOVER;
678 	}
679 
680 recover:
681 	return iscsit_recover_dataout_sequence(cmd, hdr->offset, payload_length);
682 }
683 
684 /*
685  *	Called from iscsit_handle_data_out() before DataOUT Payload is received
686  *	and CRC computed.
687  */
688 extern int iscsit_check_pre_dataout(
689 	struct iscsi_cmd *cmd,
690 	unsigned char *buf)
691 {
692 	int ret;
693 	struct iscsi_conn *conn = cmd->conn;
694 
695 	ret = iscsit_dataout_within_command_recovery_check(cmd, buf);
696 	if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
697 	    (ret == DATAOUT_CANNOT_RECOVER))
698 		return ret;
699 
700 	ret = iscsit_dataout_check_datasn(cmd, buf);
701 	if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
702 	    (ret == DATAOUT_CANNOT_RECOVER))
703 		return ret;
704 
705 	if (cmd->unsolicited_data) {
706 		ret = iscsit_dataout_check_unsolicited_sequence(cmd, buf);
707 		if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
708 		    (ret == DATAOUT_CANNOT_RECOVER))
709 			return ret;
710 	} else {
711 		ret = iscsit_dataout_check_sequence(cmd, buf);
712 		if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
713 		    (ret == DATAOUT_CANNOT_RECOVER))
714 			return ret;
715 	}
716 
717 	return (conn->sess->sess_ops->DataPDUInOrder) ?
718 		iscsit_dataout_pre_datapduinorder_yes(cmd, buf) :
719 		iscsit_dataout_pre_datapduinorder_no(cmd, buf);
720 }
721 
722 /*
723  *	Called from iscsit_handle_data_out() after DataOUT Payload is received
724  *	and CRC computed.
725  */
726 int iscsit_check_post_dataout(
727 	struct iscsi_cmd *cmd,
728 	unsigned char *buf,
729 	u8 data_crc_failed)
730 {
731 	struct iscsi_conn *conn = cmd->conn;
732 
733 	cmd->dataout_timeout_retries = 0;
734 
735 	if (!data_crc_failed)
736 		return iscsit_dataout_post_crc_passed(cmd, buf);
737 	else {
738 		if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
739 			pr_err("Unable to recover from DataOUT CRC"
740 				" failure while ERL=0, closing session.\n");
741 			iscsit_add_reject_from_cmd(ISCSI_REASON_DATA_DIGEST_ERROR,
742 					1, 0, buf, cmd);
743 			return DATAOUT_CANNOT_RECOVER;
744 		}
745 
746 		iscsit_add_reject_from_cmd(ISCSI_REASON_DATA_DIGEST_ERROR,
747 				0, 0, buf, cmd);
748 		return iscsit_dataout_post_crc_failed(cmd, buf);
749 	}
750 }
751 
752 static void iscsit_handle_time2retain_timeout(unsigned long data)
753 {
754 	struct iscsi_session *sess = (struct iscsi_session *) data;
755 	struct iscsi_portal_group *tpg = ISCSI_TPG_S(sess);
756 	struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
757 
758 	spin_lock_bh(&se_tpg->session_lock);
759 	if (sess->time2retain_timer_flags & ISCSI_TF_STOP) {
760 		spin_unlock_bh(&se_tpg->session_lock);
761 		return;
762 	}
763 	if (atomic_read(&sess->session_reinstatement)) {
764 		pr_err("Exiting Time2Retain handler because"
765 				" session_reinstatement=1\n");
766 		spin_unlock_bh(&se_tpg->session_lock);
767 		return;
768 	}
769 	sess->time2retain_timer_flags |= ISCSI_TF_EXPIRED;
770 
771 	pr_err("Time2Retain timer expired for SID: %u, cleaning up"
772 			" iSCSI session.\n", sess->sid);
773 	{
774 	struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
775 
776 	if (tiqn) {
777 		spin_lock(&tiqn->sess_err_stats.lock);
778 		strcpy(tiqn->sess_err_stats.last_sess_fail_rem_name,
779 			(void *)sess->sess_ops->InitiatorName);
780 		tiqn->sess_err_stats.last_sess_failure_type =
781 				ISCSI_SESS_ERR_CXN_TIMEOUT;
782 		tiqn->sess_err_stats.cxn_timeout_errors++;
783 		sess->conn_timeout_errors++;
784 		spin_unlock(&tiqn->sess_err_stats.lock);
785 	}
786 	}
787 
788 	spin_unlock_bh(&se_tpg->session_lock);
789 	target_put_session(sess->se_sess);
790 }
791 
792 extern void iscsit_start_time2retain_handler(struct iscsi_session *sess)
793 {
794 	int tpg_active;
795 	/*
796 	 * Only start Time2Retain timer when the assoicated TPG is still in
797 	 * an ACTIVE (eg: not disabled or shutdown) state.
798 	 */
799 	spin_lock(&ISCSI_TPG_S(sess)->tpg_state_lock);
800 	tpg_active = (ISCSI_TPG_S(sess)->tpg_state == TPG_STATE_ACTIVE);
801 	spin_unlock(&ISCSI_TPG_S(sess)->tpg_state_lock);
802 
803 	if (!tpg_active)
804 		return;
805 
806 	if (sess->time2retain_timer_flags & ISCSI_TF_RUNNING)
807 		return;
808 
809 	pr_debug("Starting Time2Retain timer for %u seconds on"
810 		" SID: %u\n", sess->sess_ops->DefaultTime2Retain, sess->sid);
811 
812 	init_timer(&sess->time2retain_timer);
813 	sess->time2retain_timer.expires =
814 		(get_jiffies_64() + sess->sess_ops->DefaultTime2Retain * HZ);
815 	sess->time2retain_timer.data = (unsigned long)sess;
816 	sess->time2retain_timer.function = iscsit_handle_time2retain_timeout;
817 	sess->time2retain_timer_flags &= ~ISCSI_TF_STOP;
818 	sess->time2retain_timer_flags |= ISCSI_TF_RUNNING;
819 	add_timer(&sess->time2retain_timer);
820 }
821 
822 /*
823  *	Called with spin_lock_bh(&struct se_portal_group->session_lock) held
824  */
825 extern int iscsit_stop_time2retain_timer(struct iscsi_session *sess)
826 {
827 	struct iscsi_portal_group *tpg = ISCSI_TPG_S(sess);
828 	struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
829 
830 	if (sess->time2retain_timer_flags & ISCSI_TF_EXPIRED)
831 		return -1;
832 
833 	if (!(sess->time2retain_timer_flags & ISCSI_TF_RUNNING))
834 		return 0;
835 
836 	sess->time2retain_timer_flags |= ISCSI_TF_STOP;
837 	spin_unlock_bh(&se_tpg->session_lock);
838 
839 	del_timer_sync(&sess->time2retain_timer);
840 
841 	spin_lock_bh(&se_tpg->session_lock);
842 	sess->time2retain_timer_flags &= ~ISCSI_TF_RUNNING;
843 	pr_debug("Stopped Time2Retain Timer for SID: %u\n",
844 			sess->sid);
845 	return 0;
846 }
847 
848 void iscsit_connection_reinstatement_rcfr(struct iscsi_conn *conn)
849 {
850 	spin_lock_bh(&conn->state_lock);
851 	if (atomic_read(&conn->connection_exit)) {
852 		spin_unlock_bh(&conn->state_lock);
853 		goto sleep;
854 	}
855 
856 	if (atomic_read(&conn->transport_failed)) {
857 		spin_unlock_bh(&conn->state_lock);
858 		goto sleep;
859 	}
860 	spin_unlock_bh(&conn->state_lock);
861 
862 	iscsi_thread_set_force_reinstatement(conn);
863 
864 sleep:
865 	wait_for_completion(&conn->conn_wait_rcfr_comp);
866 	complete(&conn->conn_post_wait_comp);
867 }
868 
869 void iscsit_cause_connection_reinstatement(struct iscsi_conn *conn, int sleep)
870 {
871 	spin_lock_bh(&conn->state_lock);
872 	if (atomic_read(&conn->connection_exit)) {
873 		spin_unlock_bh(&conn->state_lock);
874 		return;
875 	}
876 
877 	if (atomic_read(&conn->transport_failed)) {
878 		spin_unlock_bh(&conn->state_lock);
879 		return;
880 	}
881 
882 	if (atomic_read(&conn->connection_reinstatement)) {
883 		spin_unlock_bh(&conn->state_lock);
884 		return;
885 	}
886 
887 	if (iscsi_thread_set_force_reinstatement(conn) < 0) {
888 		spin_unlock_bh(&conn->state_lock);
889 		return;
890 	}
891 
892 	atomic_set(&conn->connection_reinstatement, 1);
893 	if (!sleep) {
894 		spin_unlock_bh(&conn->state_lock);
895 		return;
896 	}
897 
898 	atomic_set(&conn->sleep_on_conn_wait_comp, 1);
899 	spin_unlock_bh(&conn->state_lock);
900 
901 	wait_for_completion(&conn->conn_wait_comp);
902 	complete(&conn->conn_post_wait_comp);
903 }
904 
905 void iscsit_fall_back_to_erl0(struct iscsi_session *sess)
906 {
907 	pr_debug("Falling back to ErrorRecoveryLevel=0 for SID:"
908 			" %u\n", sess->sid);
909 
910 	atomic_set(&sess->session_fall_back_to_erl0, 1);
911 }
912 
913 static void iscsit_handle_connection_cleanup(struct iscsi_conn *conn)
914 {
915 	struct iscsi_session *sess = conn->sess;
916 
917 	if ((sess->sess_ops->ErrorRecoveryLevel == 2) &&
918 	    !atomic_read(&sess->session_reinstatement) &&
919 	    !atomic_read(&sess->session_fall_back_to_erl0))
920 		iscsit_connection_recovery_transport_reset(conn);
921 	else {
922 		pr_debug("Performing cleanup for failed iSCSI"
923 			" Connection ID: %hu from %s\n", conn->cid,
924 			sess->sess_ops->InitiatorName);
925 		iscsit_close_connection(conn);
926 	}
927 }
928 
929 extern void iscsit_take_action_for_connection_exit(struct iscsi_conn *conn)
930 {
931 	spin_lock_bh(&conn->state_lock);
932 	if (atomic_read(&conn->connection_exit)) {
933 		spin_unlock_bh(&conn->state_lock);
934 		return;
935 	}
936 	atomic_set(&conn->connection_exit, 1);
937 
938 	if (conn->conn_state == TARG_CONN_STATE_IN_LOGOUT) {
939 		spin_unlock_bh(&conn->state_lock);
940 		iscsit_close_connection(conn);
941 		return;
942 	}
943 
944 	if (conn->conn_state == TARG_CONN_STATE_CLEANUP_WAIT) {
945 		spin_unlock_bh(&conn->state_lock);
946 		return;
947 	}
948 
949 	pr_debug("Moving to TARG_CONN_STATE_CLEANUP_WAIT.\n");
950 	conn->conn_state = TARG_CONN_STATE_CLEANUP_WAIT;
951 	spin_unlock_bh(&conn->state_lock);
952 
953 	iscsit_handle_connection_cleanup(conn);
954 }
955 
956 /*
957  *	This is the simple function that makes the magic of
958  *	sync and steering happen in the follow paradoxical order:
959  *
960  *	0) Receive conn->of_marker (bytes left until next OFMarker)
961  *	   bytes into an offload buffer.  When we pass the exact number
962  *	   of bytes in conn->of_marker, iscsit_dump_data_payload() and hence
963  *	   rx_data() will automatically receive the identical u32 marker
964  *	   values and store it in conn->of_marker_offset;
965  *	1) Now conn->of_marker_offset will contain the offset to the start
966  *	   of the next iSCSI PDU.  Dump these remaining bytes into another
967  *	   offload buffer.
968  *	2) We are done!
969  *	   Next byte in the TCP stream will contain the next iSCSI PDU!
970  *	   Cool Huh?!
971  */
972 int iscsit_recover_from_unknown_opcode(struct iscsi_conn *conn)
973 {
974 	/*
975 	 * Make sure the remaining bytes to next maker is a sane value.
976 	 */
977 	if (conn->of_marker > (conn->conn_ops->OFMarkInt * 4)) {
978 		pr_err("Remaining bytes to OFMarker: %u exceeds"
979 			" OFMarkInt bytes: %u.\n", conn->of_marker,
980 				conn->conn_ops->OFMarkInt * 4);
981 		return -1;
982 	}
983 
984 	pr_debug("Advancing %u bytes in TCP stream to get to the"
985 			" next OFMarker.\n", conn->of_marker);
986 
987 	if (iscsit_dump_data_payload(conn, conn->of_marker, 0) < 0)
988 		return -1;
989 
990 	/*
991 	 * Make sure the offset marker we retrived is a valid value.
992 	 */
993 	if (conn->of_marker_offset > (ISCSI_HDR_LEN + (ISCSI_CRC_LEN * 2) +
994 	    conn->conn_ops->MaxRecvDataSegmentLength)) {
995 		pr_err("OfMarker offset value: %u exceeds limit.\n",
996 			conn->of_marker_offset);
997 		return -1;
998 	}
999 
1000 	pr_debug("Discarding %u bytes of TCP stream to get to the"
1001 			" next iSCSI Opcode.\n", conn->of_marker_offset);
1002 
1003 	if (iscsit_dump_data_payload(conn, conn->of_marker_offset, 0) < 0)
1004 		return -1;
1005 
1006 	return 0;
1007 }
1008