1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2010 Cisco Systems, Inc.
4 */
5
6/* XXX TBD some includes may be extraneous */
7
8#include <linux/module.h>
9#include <linux/moduleparam.h>
10#include <linux/utsname.h>
11#include <linux/init.h>
12#include <linux/slab.h>
13#include <linux/kthread.h>
14#include <linux/types.h>
15#include <linux/string.h>
16#include <linux/configfs.h>
17#include <linux/ctype.h>
18#include <linux/hash.h>
19#include <asm/unaligned.h>
20#include <scsi/scsi_tcq.h>
21#include <scsi/libfc.h>
22#include <scsi/fc_encode.h>
23
24#include <target/target_core_base.h>
25#include <target/target_core_fabric.h>
26
27#include "tcm_fc.h"
28
29/*
30 * Dump cmd state for debugging.
31 */
32static void _ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
33{
34	struct fc_exch *ep;
35	struct fc_seq *sp;
36	struct se_cmd *se_cmd;
37	struct scatterlist *sg;
38	int count;
39
40	se_cmd = &cmd->se_cmd;
41	pr_debug("%s: cmd %p sess %p seq %p se_cmd %p\n",
42		caller, cmd, cmd->sess, cmd->seq, se_cmd);
43
44	pr_debug("%s: cmd %p data_nents %u len %u se_cmd_flags <0x%x>\n",
45		caller, cmd, se_cmd->t_data_nents,
46	       se_cmd->data_length, se_cmd->se_cmd_flags);
47
48	for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, count)
49		pr_debug("%s: cmd %p sg %p page %p "
50			"len 0x%x off 0x%x\n",
51			caller, cmd, sg,
52			sg_page(sg), sg->length, sg->offset);
53
54	sp = cmd->seq;
55	if (sp) {
56		ep = fc_seq_exch(sp);
57		pr_debug("%s: cmd %p sid %x did %x "
58			"ox_id %x rx_id %x seq_id %x e_stat %x\n",
59			caller, cmd, ep->sid, ep->did, ep->oxid, ep->rxid,
60			sp->id, ep->esb_stat);
61	}
62}
63
64void ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
65{
66	if (unlikely(ft_debug_logging))
67		_ft_dump_cmd(cmd, caller);
68}
69
70static void ft_free_cmd(struct ft_cmd *cmd)
71{
72	struct fc_frame *fp;
73	struct ft_sess *sess;
74
75	if (!cmd)
76		return;
77	sess = cmd->sess;
78	fp = cmd->req_frame;
79	if (fr_seq(fp))
80		fc_seq_release(fr_seq(fp));
81	fc_frame_free(fp);
82	target_free_tag(sess->se_sess, &cmd->se_cmd);
83	ft_sess_put(sess);	/* undo get from lookup at recv */
84}
85
86void ft_release_cmd(struct se_cmd *se_cmd)
87{
88	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
89
90	ft_free_cmd(cmd);
91}
92
93int ft_check_stop_free(struct se_cmd *se_cmd)
94{
95	return transport_generic_free_cmd(se_cmd, 0);
96}
97
98/*
99 * Send response.
100 */
101int ft_queue_status(struct se_cmd *se_cmd)
102{
103	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
104	struct fc_frame *fp;
105	struct fcp_resp_with_ext *fcp;
106	struct fc_lport *lport;
107	struct fc_exch *ep;
108	size_t len;
109	int rc;
110
111	if (cmd->aborted)
112		return 0;
113	ft_dump_cmd(cmd, __func__);
114	ep = fc_seq_exch(cmd->seq);
115	lport = ep->lp;
116	len = sizeof(*fcp) + se_cmd->scsi_sense_length;
117	fp = fc_frame_alloc(lport, len);
118	if (!fp) {
119		se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
120		return -ENOMEM;
121	}
122
123	fcp = fc_frame_payload_get(fp, len);
124	memset(fcp, 0, len);
125	fcp->resp.fr_status = se_cmd->scsi_status;
126
127	len = se_cmd->scsi_sense_length;
128	if (len) {
129		fcp->resp.fr_flags |= FCP_SNS_LEN_VAL;
130		fcp->ext.fr_sns_len = htonl(len);
131		memcpy((fcp + 1), se_cmd->sense_buffer, len);
132	}
133
134	/*
135	 * Test underflow and overflow with one mask.  Usually both are off.
136	 * Bidirectional commands are not handled yet.
137	 */
138	if (se_cmd->se_cmd_flags & (SCF_OVERFLOW_BIT | SCF_UNDERFLOW_BIT)) {
139		if (se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT)
140			fcp->resp.fr_flags |= FCP_RESID_OVER;
141		else
142			fcp->resp.fr_flags |= FCP_RESID_UNDER;
143		fcp->ext.fr_resid = cpu_to_be32(se_cmd->residual_count);
144	}
145
146	/*
147	 * Send response.
148	 */
149	cmd->seq = fc_seq_start_next(cmd->seq);
150	fc_fill_fc_hdr(fp, FC_RCTL_DD_CMD_STATUS, ep->did, ep->sid, FC_TYPE_FCP,
151		       FC_FC_EX_CTX | FC_FC_LAST_SEQ | FC_FC_END_SEQ, 0);
152
153	rc = fc_seq_send(lport, cmd->seq, fp);
154	if (rc) {
155		pr_info_ratelimited("%s: Failed to send response frame %p, "
156				    "xid <0x%x>\n", __func__, fp, ep->xid);
157		/*
158		 * Generate a TASK_SET_FULL status to notify the initiator
159		 * to reduce it's queue_depth after the se_cmd response has
160		 * been re-queued by target-core.
161		 */
162		se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
163		return -ENOMEM;
164	}
165	fc_exch_done(cmd->seq);
166	/*
167	 * Drop the extra ACK_KREF reference taken by target_submit_cmd()
168	 * ahead of ft_check_stop_free() -> transport_generic_free_cmd()
169	 * final se_cmd->cmd_kref put.
170	 */
171	target_put_sess_cmd(&cmd->se_cmd);
172	return 0;
173}
174
175/*
176 * Send TX_RDY (transfer ready).
177 */
178int ft_write_pending(struct se_cmd *se_cmd)
179{
180	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
181	struct fc_frame *fp;
182	struct fcp_txrdy *txrdy;
183	struct fc_lport *lport;
184	struct fc_exch *ep;
185	struct fc_frame_header *fh;
186	u32 f_ctl;
187
188	ft_dump_cmd(cmd, __func__);
189
190	if (cmd->aborted)
191		return 0;
192	ep = fc_seq_exch(cmd->seq);
193	lport = ep->lp;
194	fp = fc_frame_alloc(lport, sizeof(*txrdy));
195	if (!fp)
196		return -ENOMEM; /* Signal QUEUE_FULL */
197
198	txrdy = fc_frame_payload_get(fp, sizeof(*txrdy));
199	memset(txrdy, 0, sizeof(*txrdy));
200	txrdy->ft_burst_len = htonl(se_cmd->data_length);
201
202	cmd->seq = fc_seq_start_next(cmd->seq);
203	fc_fill_fc_hdr(fp, FC_RCTL_DD_DATA_DESC, ep->did, ep->sid, FC_TYPE_FCP,
204		       FC_FC_EX_CTX | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
205
206	fh = fc_frame_header_get(fp);
207	f_ctl = ntoh24(fh->fh_f_ctl);
208
209	/* Only if it is 'Exchange Responder' */
210	if (f_ctl & FC_FC_EX_CTX) {
211		/* Target is 'exchange responder' and sending XFER_READY
212		 * to 'exchange initiator (initiator)'
213		 */
214		if ((ep->xid <= lport->lro_xid) &&
215		    (fh->fh_r_ctl == FC_RCTL_DD_DATA_DESC)) {
216			if ((se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
217			    lport->tt.ddp_target(lport, ep->xid,
218						 se_cmd->t_data_sg,
219						 se_cmd->t_data_nents))
220				cmd->was_ddp_setup = 1;
221		}
222	}
223	fc_seq_send(lport, cmd->seq, fp);
224	return 0;
225}
226
227int ft_get_cmd_state(struct se_cmd *se_cmd)
228{
229	return 0;
230}
231
232/*
233 * FC sequence response handler for follow-on sequences (data) and aborts.
234 */
235static void ft_recv_seq(struct fc_seq *sp, struct fc_frame *fp, void *arg)
236{
237	struct ft_cmd *cmd = arg;
238	struct fc_frame_header *fh;
239
240	if (IS_ERR(fp)) {
241		/* XXX need to find cmd if queued */
242		cmd->seq = NULL;
243		cmd->aborted = true;
244		return;
245	}
246
247	fh = fc_frame_header_get(fp);
248
249	switch (fh->fh_r_ctl) {
250	case FC_RCTL_DD_SOL_DATA:	/* write data */
251		ft_recv_write_data(cmd, fp);
252		break;
253	case FC_RCTL_DD_UNSOL_CTL:	/* command */
254	case FC_RCTL_DD_SOL_CTL:	/* transfer ready */
255	case FC_RCTL_DD_DATA_DESC:	/* transfer ready */
256	default:
257		pr_debug("%s: unhandled frame r_ctl %x\n",
258		       __func__, fh->fh_r_ctl);
259		ft_invl_hw_context(cmd);
260		fc_frame_free(fp);
261		transport_generic_free_cmd(&cmd->se_cmd, 0);
262		break;
263	}
264}
265
266/*
267 * Send a FCP response including SCSI status and optional FCP rsp_code.
268 * status is SAM_STAT_GOOD (zero) iff code is valid.
269 * This is used in error cases, such as allocation failures.
270 */
271static void ft_send_resp_status(struct fc_lport *lport,
272				const struct fc_frame *rx_fp,
273				u32 status, enum fcp_resp_rsp_codes code)
274{
275	struct fc_frame *fp;
276	struct fc_seq *sp;
277	const struct fc_frame_header *fh;
278	size_t len;
279	struct fcp_resp_with_ext *fcp;
280	struct fcp_resp_rsp_info *info;
281
282	fh = fc_frame_header_get(rx_fp);
283	pr_debug("FCP error response: did %x oxid %x status %x code %x\n",
284		  ntoh24(fh->fh_s_id), ntohs(fh->fh_ox_id), status, code);
285	len = sizeof(*fcp);
286	if (status == SAM_STAT_GOOD)
287		len += sizeof(*info);
288	fp = fc_frame_alloc(lport, len);
289	if (!fp)
290		return;
291	fcp = fc_frame_payload_get(fp, len);
292	memset(fcp, 0, len);
293	fcp->resp.fr_status = status;
294	if (status == SAM_STAT_GOOD) {
295		fcp->ext.fr_rsp_len = htonl(sizeof(*info));
296		fcp->resp.fr_flags |= FCP_RSP_LEN_VAL;
297		info = (struct fcp_resp_rsp_info *)(fcp + 1);
298		info->rsp_code = code;
299	}
300
301	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_DD_CMD_STATUS, 0);
302	sp = fr_seq(fp);
303	if (sp) {
304		fc_seq_send(lport, sp, fp);
305		fc_exch_done(sp);
306	} else {
307		lport->tt.frame_send(lport, fp);
308	}
309}
310
311/*
312 * Send error or task management response.
313 */
314static void ft_send_resp_code(struct ft_cmd *cmd,
315			      enum fcp_resp_rsp_codes code)
316{
317	ft_send_resp_status(cmd->sess->tport->lport,
318			    cmd->req_frame, SAM_STAT_GOOD, code);
319}
320
321
322/*
323 * Send error or task management response.
324 * Always frees the cmd and associated state.
325 */
326static void ft_send_resp_code_and_free(struct ft_cmd *cmd,
327				      enum fcp_resp_rsp_codes code)
328{
329	ft_send_resp_code(cmd, code);
330	ft_free_cmd(cmd);
331}
332
333/*
334 * Handle Task Management Request.
335 */
336static void ft_send_tm(struct ft_cmd *cmd)
337{
338	struct fcp_cmnd *fcp;
339	int rc;
340	u8 tm_func;
341
342	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));
343
344	switch (fcp->fc_tm_flags) {
345	case FCP_TMF_LUN_RESET:
346		tm_func = TMR_LUN_RESET;
347		break;
348	case FCP_TMF_TGT_RESET:
349		tm_func = TMR_TARGET_WARM_RESET;
350		break;
351	case FCP_TMF_CLR_TASK_SET:
352		tm_func = TMR_CLEAR_TASK_SET;
353		break;
354	case FCP_TMF_ABT_TASK_SET:
355		tm_func = TMR_ABORT_TASK_SET;
356		break;
357	case FCP_TMF_CLR_ACA:
358		tm_func = TMR_CLEAR_ACA;
359		break;
360	default:
361		/*
362		 * FCP4r01 indicates having a combination of
363		 * tm_flags set is invalid.
364		 */
365		pr_debug("invalid FCP tm_flags %x\n", fcp->fc_tm_flags);
366		ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
367		return;
368	}
369
370	/* FIXME: Add referenced task tag for ABORT_TASK */
371	rc = target_submit_tmr(&cmd->se_cmd, cmd->sess->se_sess,
372		&cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
373		cmd, tm_func, GFP_KERNEL, 0, TARGET_SCF_ACK_KREF);
374	if (rc < 0)
375		ft_send_resp_code_and_free(cmd, FCP_TMF_FAILED);
376}
377
378/*
379 * Send status from completed task management request.
380 */
381void ft_queue_tm_resp(struct se_cmd *se_cmd)
382{
383	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
384	struct se_tmr_req *tmr = se_cmd->se_tmr_req;
385	enum fcp_resp_rsp_codes code;
386
387	if (cmd->aborted)
388		return;
389	switch (tmr->response) {
390	case TMR_FUNCTION_COMPLETE:
391		code = FCP_TMF_CMPL;
392		break;
393	case TMR_LUN_DOES_NOT_EXIST:
394		code = FCP_TMF_INVALID_LUN;
395		break;
396	case TMR_FUNCTION_REJECTED:
397		code = FCP_TMF_REJECTED;
398		break;
399	case TMR_TASK_DOES_NOT_EXIST:
400	case TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED:
401	default:
402		code = FCP_TMF_FAILED;
403		break;
404	}
405	pr_debug("tmr fn %d resp %d fcp code %d\n",
406		  tmr->function, tmr->response, code);
407	ft_send_resp_code(cmd, code);
408	/*
409	 * Drop the extra ACK_KREF reference taken by target_submit_tmr()
410	 * ahead of ft_check_stop_free() -> transport_generic_free_cmd()
411	 * final se_cmd->cmd_kref put.
412	 */
413	target_put_sess_cmd(&cmd->se_cmd);
414}
415
416void ft_aborted_task(struct se_cmd *se_cmd)
417{
418	return;
419}
420
421static void ft_send_work(struct work_struct *work);
422
423/*
424 * Handle incoming FCP command.
425 */
426static void ft_recv_cmd(struct ft_sess *sess, struct fc_frame *fp)
427{
428	struct ft_cmd *cmd;
429	struct fc_lport *lport = sess->tport->lport;
430	struct se_session *se_sess = sess->se_sess;
431	int tag, cpu;
432
433	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
434	if (tag < 0)
435		goto busy;
436
437	cmd = &((struct ft_cmd *)se_sess->sess_cmd_map)[tag];
438	memset(cmd, 0, sizeof(struct ft_cmd));
439
440	cmd->se_cmd.map_tag = tag;
441	cmd->se_cmd.map_cpu = cpu;
442	cmd->sess = sess;
443	cmd->seq = fc_seq_assign(lport, fp);
444	if (!cmd->seq) {
445		target_free_tag(se_sess, &cmd->se_cmd);
446		goto busy;
447	}
448	cmd->req_frame = fp;		/* hold frame during cmd */
449
450	INIT_WORK(&cmd->work, ft_send_work);
451	queue_work(sess->tport->tpg->workqueue, &cmd->work);
452	return;
453
454busy:
455	pr_debug("cmd or seq allocation failure - sending BUSY\n");
456	ft_send_resp_status(lport, fp, SAM_STAT_BUSY, 0);
457	fc_frame_free(fp);
458	ft_sess_put(sess);		/* undo get from lookup */
459}
460
461
462/*
463 * Handle incoming FCP frame.
464 * Caller has verified that the frame is type FCP.
465 */
466void ft_recv_req(struct ft_sess *sess, struct fc_frame *fp)
467{
468	struct fc_frame_header *fh = fc_frame_header_get(fp);
469
470	switch (fh->fh_r_ctl) {
471	case FC_RCTL_DD_UNSOL_CMD:	/* command */
472		ft_recv_cmd(sess, fp);
473		break;
474	case FC_RCTL_DD_SOL_DATA:	/* write data */
475	case FC_RCTL_DD_UNSOL_CTL:
476	case FC_RCTL_DD_SOL_CTL:
477	case FC_RCTL_DD_DATA_DESC:	/* transfer ready */
478	case FC_RCTL_ELS4_REQ:		/* SRR, perhaps */
479	default:
480		pr_debug("%s: unhandled frame r_ctl %x\n",
481		       __func__, fh->fh_r_ctl);
482		fc_frame_free(fp);
483		ft_sess_put(sess);	/* undo get from lookup */
484		break;
485	}
486}
487
488/*
489 * Send new command to target.
490 */
491static void ft_send_work(struct work_struct *work)
492{
493	struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
494	struct fc_frame_header *fh = fc_frame_header_get(cmd->req_frame);
495	struct fcp_cmnd *fcp;
496	int data_dir = 0;
497	int task_attr;
498
499	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));
500	if (!fcp)
501		goto err;
502
503	if (fcp->fc_flags & FCP_CFL_LEN_MASK)
504		goto err;		/* not handling longer CDBs yet */
505
506	/*
507	 * Check for FCP task management flags
508	 */
509	if (fcp->fc_tm_flags) {
510		ft_send_tm(cmd);
511		return;
512	}
513
514	switch (fcp->fc_flags & (FCP_CFL_RDDATA | FCP_CFL_WRDATA)) {
515	case 0:
516		data_dir = DMA_NONE;
517		break;
518	case FCP_CFL_RDDATA:
519		data_dir = DMA_FROM_DEVICE;
520		break;
521	case FCP_CFL_WRDATA:
522		data_dir = DMA_TO_DEVICE;
523		break;
524	case FCP_CFL_WRDATA | FCP_CFL_RDDATA:
525		goto err;	/* TBD not supported by tcm_fc yet */
526	}
527	/*
528	 * Locate the SAM Task Attr from fc_pri_ta
529	 */
530	switch (fcp->fc_pri_ta & FCP_PTA_MASK) {
531	case FCP_PTA_HEADQ:
532		task_attr = TCM_HEAD_TAG;
533		break;
534	case FCP_PTA_ORDERED:
535		task_attr = TCM_ORDERED_TAG;
536		break;
537	case FCP_PTA_ACA:
538		task_attr = TCM_ACA_TAG;
539		break;
540	case FCP_PTA_SIMPLE:
541	default:
542		task_attr = TCM_SIMPLE_TAG;
543	}
544
545	fc_seq_set_resp(cmd->seq, ft_recv_seq, cmd);
546	cmd->se_cmd.tag = fc_seq_exch(cmd->seq)->rxid;
547	/*
548	 * Use a single se_cmd->cmd_kref as we expect to release se_cmd
549	 * directly from ft_check_stop_free callback in response path.
550	 */
551	if (target_submit_cmd(&cmd->se_cmd, cmd->sess->se_sess, fcp->fc_cdb,
552			      &cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
553			      ntohl(fcp->fc_dl), task_attr, data_dir,
554			      TARGET_SCF_ACK_KREF))
555		goto err;
556
557	pr_debug("r_ctl %x target_submit_cmd %p\n", fh->fh_r_ctl, cmd);
558	return;
559
560err:
561	ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
562}
563