1/*
2 * Copyright (c) 2010 Cisco Systems, Inc.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18/* XXX TBD some includes may be extraneous */
19
20#include <linux/module.h>
21#include <linux/moduleparam.h>
22#include <linux/utsname.h>
23#include <linux/init.h>
24#include <linux/slab.h>
25#include <linux/kthread.h>
26#include <linux/types.h>
27#include <linux/string.h>
28#include <linux/configfs.h>
29#include <linux/ctype.h>
30#include <linux/hash.h>
31#include <linux/percpu_ida.h>
32#include <asm/unaligned.h>
33#include <scsi/scsi.h>
34#include <scsi/scsi_host.h>
35#include <scsi/scsi_device.h>
36#include <scsi/scsi_cmnd.h>
37#include <scsi/scsi_tcq.h>
38#include <scsi/libfc.h>
39#include <scsi/fc_encode.h>
40
41#include <target/target_core_base.h>
42#include <target/target_core_fabric.h>
43#include <target/target_core_configfs.h>
44#include <target/configfs_macros.h>
45
46#include "tcm_fc.h"
47
48/*
49 * Dump cmd state for debugging.
50 */
51static void _ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
52{
53	struct fc_exch *ep;
54	struct fc_seq *sp;
55	struct se_cmd *se_cmd;
56	struct scatterlist *sg;
57	int count;
58
59	se_cmd = &cmd->se_cmd;
60	pr_debug("%s: cmd %p sess %p seq %p se_cmd %p\n",
61		caller, cmd, cmd->sess, cmd->seq, se_cmd);
62
63	pr_debug("%s: cmd %p data_nents %u len %u se_cmd_flags <0x%x>\n",
64		caller, cmd, se_cmd->t_data_nents,
65	       se_cmd->data_length, se_cmd->se_cmd_flags);
66
67	for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, count)
68		pr_debug("%s: cmd %p sg %p page %p "
69			"len 0x%x off 0x%x\n",
70			caller, cmd, sg,
71			sg_page(sg), sg->length, sg->offset);
72
73	sp = cmd->seq;
74	if (sp) {
75		ep = fc_seq_exch(sp);
76		pr_debug("%s: cmd %p sid %x did %x "
77			"ox_id %x rx_id %x seq_id %x e_stat %x\n",
78			caller, cmd, ep->sid, ep->did, ep->oxid, ep->rxid,
79			sp->id, ep->esb_stat);
80	}
81}
82
83void ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
84{
85	if (unlikely(ft_debug_logging))
86		_ft_dump_cmd(cmd, caller);
87}
88
89static void ft_free_cmd(struct ft_cmd *cmd)
90{
91	struct fc_frame *fp;
92	struct fc_lport *lport;
93	struct ft_sess *sess;
94
95	if (!cmd)
96		return;
97	sess = cmd->sess;
98	fp = cmd->req_frame;
99	lport = fr_dev(fp);
100	if (fr_seq(fp))
101		lport->tt.seq_release(fr_seq(fp));
102	fc_frame_free(fp);
103	percpu_ida_free(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag);
104	ft_sess_put(sess);	/* undo get from lookup at recv */
105}
106
107void ft_release_cmd(struct se_cmd *se_cmd)
108{
109	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
110
111	ft_free_cmd(cmd);
112}
113
114int ft_check_stop_free(struct se_cmd *se_cmd)
115{
116	transport_generic_free_cmd(se_cmd, 0);
117	return 1;
118}
119
120/*
121 * Send response.
122 */
123int ft_queue_status(struct se_cmd *se_cmd)
124{
125	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
126	struct fc_frame *fp;
127	struct fcp_resp_with_ext *fcp;
128	struct fc_lport *lport;
129	struct fc_exch *ep;
130	size_t len;
131	int rc;
132
133	if (cmd->aborted)
134		return 0;
135	ft_dump_cmd(cmd, __func__);
136	ep = fc_seq_exch(cmd->seq);
137	lport = ep->lp;
138	len = sizeof(*fcp) + se_cmd->scsi_sense_length;
139	fp = fc_frame_alloc(lport, len);
140	if (!fp) {
141		se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
142		return -ENOMEM;
143	}
144
145	fcp = fc_frame_payload_get(fp, len);
146	memset(fcp, 0, len);
147	fcp->resp.fr_status = se_cmd->scsi_status;
148
149	len = se_cmd->scsi_sense_length;
150	if (len) {
151		fcp->resp.fr_flags |= FCP_SNS_LEN_VAL;
152		fcp->ext.fr_sns_len = htonl(len);
153		memcpy((fcp + 1), se_cmd->sense_buffer, len);
154	}
155
156	/*
157	 * Test underflow and overflow with one mask.  Usually both are off.
158	 * Bidirectional commands are not handled yet.
159	 */
160	if (se_cmd->se_cmd_flags & (SCF_OVERFLOW_BIT | SCF_UNDERFLOW_BIT)) {
161		if (se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT)
162			fcp->resp.fr_flags |= FCP_RESID_OVER;
163		else
164			fcp->resp.fr_flags |= FCP_RESID_UNDER;
165		fcp->ext.fr_resid = cpu_to_be32(se_cmd->residual_count);
166	}
167
168	/*
169	 * Send response.
170	 */
171	cmd->seq = lport->tt.seq_start_next(cmd->seq);
172	fc_fill_fc_hdr(fp, FC_RCTL_DD_CMD_STATUS, ep->did, ep->sid, FC_TYPE_FCP,
173		       FC_FC_EX_CTX | FC_FC_LAST_SEQ | FC_FC_END_SEQ, 0);
174
175	rc = lport->tt.seq_send(lport, cmd->seq, fp);
176	if (rc) {
177		pr_info_ratelimited("%s: Failed to send response frame %p, "
178				    "xid <0x%x>\n", __func__, fp, ep->xid);
179		/*
180		 * Generate a TASK_SET_FULL status to notify the initiator
181		 * to reduce it's queue_depth after the se_cmd response has
182		 * been re-queued by target-core.
183		 */
184		se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
185		return -ENOMEM;
186	}
187	lport->tt.exch_done(cmd->seq);
188	return 0;
189}
190
191int ft_write_pending_status(struct se_cmd *se_cmd)
192{
193	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
194
195	return cmd->write_data_len != se_cmd->data_length;
196}
197
198/*
199 * Send TX_RDY (transfer ready).
200 */
201int ft_write_pending(struct se_cmd *se_cmd)
202{
203	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
204	struct fc_frame *fp;
205	struct fcp_txrdy *txrdy;
206	struct fc_lport *lport;
207	struct fc_exch *ep;
208	struct fc_frame_header *fh;
209	u32 f_ctl;
210
211	ft_dump_cmd(cmd, __func__);
212
213	if (cmd->aborted)
214		return 0;
215	ep = fc_seq_exch(cmd->seq);
216	lport = ep->lp;
217	fp = fc_frame_alloc(lport, sizeof(*txrdy));
218	if (!fp)
219		return -ENOMEM; /* Signal QUEUE_FULL */
220
221	txrdy = fc_frame_payload_get(fp, sizeof(*txrdy));
222	memset(txrdy, 0, sizeof(*txrdy));
223	txrdy->ft_burst_len = htonl(se_cmd->data_length);
224
225	cmd->seq = lport->tt.seq_start_next(cmd->seq);
226	fc_fill_fc_hdr(fp, FC_RCTL_DD_DATA_DESC, ep->did, ep->sid, FC_TYPE_FCP,
227		       FC_FC_EX_CTX | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
228
229	fh = fc_frame_header_get(fp);
230	f_ctl = ntoh24(fh->fh_f_ctl);
231
232	/* Only if it is 'Exchange Responder' */
233	if (f_ctl & FC_FC_EX_CTX) {
234		/* Target is 'exchange responder' and sending XFER_READY
235		 * to 'exchange initiator (initiator)'
236		 */
237		if ((ep->xid <= lport->lro_xid) &&
238		    (fh->fh_r_ctl == FC_RCTL_DD_DATA_DESC)) {
239			if ((se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
240			    lport->tt.ddp_target(lport, ep->xid,
241						 se_cmd->t_data_sg,
242						 se_cmd->t_data_nents))
243				cmd->was_ddp_setup = 1;
244		}
245	}
246	lport->tt.seq_send(lport, cmd->seq, fp);
247	return 0;
248}
249
250u32 ft_get_task_tag(struct se_cmd *se_cmd)
251{
252	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
253
254	if (cmd->aborted)
255		return ~0;
256	return fc_seq_exch(cmd->seq)->rxid;
257}
258
259int ft_get_cmd_state(struct se_cmd *se_cmd)
260{
261	return 0;
262}
263
264/*
265 * FC sequence response handler for follow-on sequences (data) and aborts.
266 */
267static void ft_recv_seq(struct fc_seq *sp, struct fc_frame *fp, void *arg)
268{
269	struct ft_cmd *cmd = arg;
270	struct fc_frame_header *fh;
271
272	if (unlikely(IS_ERR(fp))) {
273		/* XXX need to find cmd if queued */
274		cmd->seq = NULL;
275		cmd->aborted = true;
276		return;
277	}
278
279	fh = fc_frame_header_get(fp);
280
281	switch (fh->fh_r_ctl) {
282	case FC_RCTL_DD_SOL_DATA:	/* write data */
283		ft_recv_write_data(cmd, fp);
284		break;
285	case FC_RCTL_DD_UNSOL_CTL:	/* command */
286	case FC_RCTL_DD_SOL_CTL:	/* transfer ready */
287	case FC_RCTL_DD_DATA_DESC:	/* transfer ready */
288	default:
289		pr_debug("%s: unhandled frame r_ctl %x\n",
290		       __func__, fh->fh_r_ctl);
291		ft_invl_hw_context(cmd);
292		fc_frame_free(fp);
293		transport_generic_free_cmd(&cmd->se_cmd, 0);
294		break;
295	}
296}
297
298/*
299 * Send a FCP response including SCSI status and optional FCP rsp_code.
300 * status is SAM_STAT_GOOD (zero) iff code is valid.
301 * This is used in error cases, such as allocation failures.
302 */
303static void ft_send_resp_status(struct fc_lport *lport,
304				const struct fc_frame *rx_fp,
305				u32 status, enum fcp_resp_rsp_codes code)
306{
307	struct fc_frame *fp;
308	struct fc_seq *sp;
309	const struct fc_frame_header *fh;
310	size_t len;
311	struct fcp_resp_with_ext *fcp;
312	struct fcp_resp_rsp_info *info;
313
314	fh = fc_frame_header_get(rx_fp);
315	pr_debug("FCP error response: did %x oxid %x status %x code %x\n",
316		  ntoh24(fh->fh_s_id), ntohs(fh->fh_ox_id), status, code);
317	len = sizeof(*fcp);
318	if (status == SAM_STAT_GOOD)
319		len += sizeof(*info);
320	fp = fc_frame_alloc(lport, len);
321	if (!fp)
322		return;
323	fcp = fc_frame_payload_get(fp, len);
324	memset(fcp, 0, len);
325	fcp->resp.fr_status = status;
326	if (status == SAM_STAT_GOOD) {
327		fcp->ext.fr_rsp_len = htonl(sizeof(*info));
328		fcp->resp.fr_flags |= FCP_RSP_LEN_VAL;
329		info = (struct fcp_resp_rsp_info *)(fcp + 1);
330		info->rsp_code = code;
331	}
332
333	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_DD_CMD_STATUS, 0);
334	sp = fr_seq(fp);
335	if (sp) {
336		lport->tt.seq_send(lport, sp, fp);
337		lport->tt.exch_done(sp);
338	} else {
339		lport->tt.frame_send(lport, fp);
340	}
341}
342
343/*
344 * Send error or task management response.
345 */
346static void ft_send_resp_code(struct ft_cmd *cmd,
347			      enum fcp_resp_rsp_codes code)
348{
349	ft_send_resp_status(cmd->sess->tport->lport,
350			    cmd->req_frame, SAM_STAT_GOOD, code);
351}
352
353
354/*
355 * Send error or task management response.
356 * Always frees the cmd and associated state.
357 */
358static void ft_send_resp_code_and_free(struct ft_cmd *cmd,
359				      enum fcp_resp_rsp_codes code)
360{
361	ft_send_resp_code(cmd, code);
362	ft_free_cmd(cmd);
363}
364
365/*
366 * Handle Task Management Request.
367 */
368static void ft_send_tm(struct ft_cmd *cmd)
369{
370	struct fcp_cmnd *fcp;
371	int rc;
372	u8 tm_func;
373
374	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));
375
376	switch (fcp->fc_tm_flags) {
377	case FCP_TMF_LUN_RESET:
378		tm_func = TMR_LUN_RESET;
379		break;
380	case FCP_TMF_TGT_RESET:
381		tm_func = TMR_TARGET_WARM_RESET;
382		break;
383	case FCP_TMF_CLR_TASK_SET:
384		tm_func = TMR_CLEAR_TASK_SET;
385		break;
386	case FCP_TMF_ABT_TASK_SET:
387		tm_func = TMR_ABORT_TASK_SET;
388		break;
389	case FCP_TMF_CLR_ACA:
390		tm_func = TMR_CLEAR_ACA;
391		break;
392	default:
393		/*
394		 * FCP4r01 indicates having a combination of
395		 * tm_flags set is invalid.
396		 */
397		pr_debug("invalid FCP tm_flags %x\n", fcp->fc_tm_flags);
398		ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
399		return;
400	}
401
402	/* FIXME: Add referenced task tag for ABORT_TASK */
403	rc = target_submit_tmr(&cmd->se_cmd, cmd->sess->se_sess,
404		&cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
405		cmd, tm_func, GFP_KERNEL, 0, 0);
406	if (rc < 0)
407		ft_send_resp_code_and_free(cmd, FCP_TMF_FAILED);
408}
409
410/*
411 * Send status from completed task management request.
412 */
413void ft_queue_tm_resp(struct se_cmd *se_cmd)
414{
415	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
416	struct se_tmr_req *tmr = se_cmd->se_tmr_req;
417	enum fcp_resp_rsp_codes code;
418
419	if (cmd->aborted)
420		return;
421	switch (tmr->response) {
422	case TMR_FUNCTION_COMPLETE:
423		code = FCP_TMF_CMPL;
424		break;
425	case TMR_LUN_DOES_NOT_EXIST:
426		code = FCP_TMF_INVALID_LUN;
427		break;
428	case TMR_FUNCTION_REJECTED:
429		code = FCP_TMF_REJECTED;
430		break;
431	case TMR_TASK_DOES_NOT_EXIST:
432	case TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED:
433	default:
434		code = FCP_TMF_FAILED;
435		break;
436	}
437	pr_debug("tmr fn %d resp %d fcp code %d\n",
438		  tmr->function, tmr->response, code);
439	ft_send_resp_code(cmd, code);
440}
441
442void ft_aborted_task(struct se_cmd *se_cmd)
443{
444	return;
445}
446
447static void ft_send_work(struct work_struct *work);
448
449/*
450 * Handle incoming FCP command.
451 */
452static void ft_recv_cmd(struct ft_sess *sess, struct fc_frame *fp)
453{
454	struct ft_cmd *cmd;
455	struct fc_lport *lport = sess->tport->lport;
456	struct se_session *se_sess = sess->se_sess;
457	int tag;
458
459	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
460	if (tag < 0)
461		goto busy;
462
463	cmd = &((struct ft_cmd *)se_sess->sess_cmd_map)[tag];
464	memset(cmd, 0, sizeof(struct ft_cmd));
465
466	cmd->se_cmd.map_tag = tag;
467	cmd->sess = sess;
468	cmd->seq = lport->tt.seq_assign(lport, fp);
469	if (!cmd->seq) {
470		percpu_ida_free(&se_sess->sess_tag_pool, tag);
471		goto busy;
472	}
473	cmd->req_frame = fp;		/* hold frame during cmd */
474
475	INIT_WORK(&cmd->work, ft_send_work);
476	queue_work(sess->tport->tpg->workqueue, &cmd->work);
477	return;
478
479busy:
480	pr_debug("cmd or seq allocation failure - sending BUSY\n");
481	ft_send_resp_status(lport, fp, SAM_STAT_BUSY, 0);
482	fc_frame_free(fp);
483	ft_sess_put(sess);		/* undo get from lookup */
484}
485
486
487/*
488 * Handle incoming FCP frame.
489 * Caller has verified that the frame is type FCP.
490 */
491void ft_recv_req(struct ft_sess *sess, struct fc_frame *fp)
492{
493	struct fc_frame_header *fh = fc_frame_header_get(fp);
494
495	switch (fh->fh_r_ctl) {
496	case FC_RCTL_DD_UNSOL_CMD:	/* command */
497		ft_recv_cmd(sess, fp);
498		break;
499	case FC_RCTL_DD_SOL_DATA:	/* write data */
500	case FC_RCTL_DD_UNSOL_CTL:
501	case FC_RCTL_DD_SOL_CTL:
502	case FC_RCTL_DD_DATA_DESC:	/* transfer ready */
503	case FC_RCTL_ELS4_REQ:		/* SRR, perhaps */
504	default:
505		pr_debug("%s: unhandled frame r_ctl %x\n",
506		       __func__, fh->fh_r_ctl);
507		fc_frame_free(fp);
508		ft_sess_put(sess);	/* undo get from lookup */
509		break;
510	}
511}
512
513/*
514 * Send new command to target.
515 */
516static void ft_send_work(struct work_struct *work)
517{
518	struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
519	struct fc_frame_header *fh = fc_frame_header_get(cmd->req_frame);
520	struct fcp_cmnd *fcp;
521	int data_dir = 0;
522	int task_attr;
523
524	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));
525	if (!fcp)
526		goto err;
527
528	if (fcp->fc_flags & FCP_CFL_LEN_MASK)
529		goto err;		/* not handling longer CDBs yet */
530
531	/*
532	 * Check for FCP task management flags
533	 */
534	if (fcp->fc_tm_flags) {
535		ft_send_tm(cmd);
536		return;
537	}
538
539	switch (fcp->fc_flags & (FCP_CFL_RDDATA | FCP_CFL_WRDATA)) {
540	case 0:
541		data_dir = DMA_NONE;
542		break;
543	case FCP_CFL_RDDATA:
544		data_dir = DMA_FROM_DEVICE;
545		break;
546	case FCP_CFL_WRDATA:
547		data_dir = DMA_TO_DEVICE;
548		break;
549	case FCP_CFL_WRDATA | FCP_CFL_RDDATA:
550		goto err;	/* TBD not supported by tcm_fc yet */
551	}
552	/*
553	 * Locate the SAM Task Attr from fc_pri_ta
554	 */
555	switch (fcp->fc_pri_ta & FCP_PTA_MASK) {
556	case FCP_PTA_HEADQ:
557		task_attr = MSG_HEAD_TAG;
558		break;
559	case FCP_PTA_ORDERED:
560		task_attr = MSG_ORDERED_TAG;
561		break;
562	case FCP_PTA_ACA:
563		task_attr = MSG_ACA_TAG;
564		break;
565	case FCP_PTA_SIMPLE: /* Fallthrough */
566	default:
567		task_attr = MSG_SIMPLE_TAG;
568	}
569
570	fc_seq_exch(cmd->seq)->lp->tt.seq_set_resp(cmd->seq, ft_recv_seq, cmd);
571	/*
572	 * Use a single se_cmd->cmd_kref as we expect to release se_cmd
573	 * directly from ft_check_stop_free callback in response path.
574	 */
575	if (target_submit_cmd(&cmd->se_cmd, cmd->sess->se_sess, fcp->fc_cdb,
576			      &cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
577			      ntohl(fcp->fc_dl), task_attr, data_dir, 0))
578		goto err;
579
580	pr_debug("r_ctl %x alloc target_submit_cmd\n", fh->fh_r_ctl);
581	return;
582
583err:
584	ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
585}
586