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 <linux/rcupdate.h>
20#include <linux/rculist.h>
21#include <linux/kref.h>
22#include <asm/unaligned.h>
23#include <scsi/libfc.h>
24
25#include <target/target_core_base.h>
26#include <target/target_core_fabric.h>
27
28#include "tcm_fc.h"
29
30#define TFC_SESS_DBG(lport, fmt, args...) \
31	pr_debug("host%u: rport %6.6x: " fmt,	   \
32		 (lport)->host->host_no,	   \
33		 (lport)->port_id, ##args )
34
35static void ft_sess_delete_all(struct ft_tport *);
36
37/*
38 * Lookup or allocate target local port.
39 * Caller holds ft_lport_lock.
40 */
41static struct ft_tport *ft_tport_get(struct fc_lport *lport)
42{
43	struct ft_tpg *tpg;
44	struct ft_tport *tport;
45	int i;
46
47	tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
48					  lockdep_is_held(&ft_lport_lock));
49	if (tport && tport->tpg)
50		return tport;
51
52	tpg = ft_lport_find_tpg(lport);
53	if (!tpg)
54		return NULL;
55
56	if (tport) {
57		tport->tpg = tpg;
58		tpg->tport = tport;
59		return tport;
60	}
61
62	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
63	if (!tport)
64		return NULL;
65
66	tport->lport = lport;
67	tport->tpg = tpg;
68	tpg->tport = tport;
69	for (i = 0; i < FT_SESS_HASH_SIZE; i++)
70		INIT_HLIST_HEAD(&tport->hash[i]);
71
72	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
73	return tport;
74}
75
76/*
77 * Delete a target local port.
78 * Caller holds ft_lport_lock.
79 */
80static void ft_tport_delete(struct ft_tport *tport)
81{
82	struct fc_lport *lport;
83	struct ft_tpg *tpg;
84
85	ft_sess_delete_all(tport);
86	lport = tport->lport;
87	lport->service_params &= ~FCP_SPPF_TARG_FCN;
88	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
89	RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
90
91	tpg = tport->tpg;
92	if (tpg) {
93		tpg->tport = NULL;
94		tport->tpg = NULL;
95	}
96	kfree_rcu(tport, rcu);
97}
98
99/*
100 * Add local port.
101 * Called thru fc_lport_iterate().
102 */
103void ft_lport_add(struct fc_lport *lport, void *arg)
104{
105	mutex_lock(&ft_lport_lock);
106	ft_tport_get(lport);
107	lport->service_params |= FCP_SPPF_TARG_FCN;
108	mutex_unlock(&ft_lport_lock);
109}
110
111/*
112 * Delete local port.
113 * Called thru fc_lport_iterate().
114 */
115void ft_lport_del(struct fc_lport *lport, void *arg)
116{
117	struct ft_tport *tport;
118
119	mutex_lock(&ft_lport_lock);
120	tport = lport->prov[FC_TYPE_FCP];
121	if (tport)
122		ft_tport_delete(tport);
123	mutex_unlock(&ft_lport_lock);
124}
125
126/*
127 * Notification of local port change from libfc.
128 * Create or delete local port and associated tport.
129 */
130int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
131{
132	struct fc_lport *lport = arg;
133
134	switch (event) {
135	case FC_LPORT_EV_ADD:
136		ft_lport_add(lport, NULL);
137		break;
138	case FC_LPORT_EV_DEL:
139		ft_lport_del(lport, NULL);
140		break;
141	}
142	return NOTIFY_DONE;
143}
144
145/*
146 * Hash function for FC_IDs.
147 */
148static u32 ft_sess_hash(u32 port_id)
149{
150	return hash_32(port_id, FT_SESS_HASH_BITS);
151}
152
153/*
154 * Find session in local port.
155 * Sessions and hash lists are RCU-protected.
156 * A reference is taken which must be eventually freed.
157 */
158static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
159{
160	struct ft_tport *tport;
161	struct hlist_head *head;
162	struct ft_sess *sess;
163	char *reason = "no session created";
164
165	rcu_read_lock();
166	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
167	if (!tport) {
168		reason = "not an FCP port";
169		goto out;
170	}
171
172	head = &tport->hash[ft_sess_hash(port_id)];
173	hlist_for_each_entry_rcu(sess, head, hash) {
174		if (sess->port_id == port_id) {
175			kref_get(&sess->kref);
176			rcu_read_unlock();
177			TFC_SESS_DBG(lport, "port_id %x found %p\n",
178				     port_id, sess);
179			return sess;
180		}
181	}
182out:
183	rcu_read_unlock();
184	TFC_SESS_DBG(lport, "port_id %x not found, %s\n",
185		     port_id, reason);
186	return NULL;
187}
188
189static int ft_sess_alloc_cb(struct se_portal_group *se_tpg,
190			    struct se_session *se_sess, void *p)
191{
192	struct ft_sess *sess = p;
193	struct ft_tport *tport = sess->tport;
194	struct hlist_head *head = &tport->hash[ft_sess_hash(sess->port_id)];
195
196	TFC_SESS_DBG(tport->lport, "port_id %x sess %p\n", sess->port_id, sess);
197	hlist_add_head_rcu(&sess->hash, head);
198	tport->sess_count++;
199
200	return 0;
201}
202
203/*
204 * Allocate session and enter it in the hash for the local port.
205 * Caller holds ft_lport_lock.
206 */
207static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
208				      struct fc_rport_priv *rdata)
209{
210	struct se_portal_group *se_tpg = &tport->tpg->se_tpg;
211	struct ft_sess *sess;
212	struct hlist_head *head;
213	unsigned char initiatorname[TRANSPORT_IQN_LEN];
214
215	ft_format_wwn(&initiatorname[0], TRANSPORT_IQN_LEN, rdata->ids.port_name);
216
217	head = &tport->hash[ft_sess_hash(port_id)];
218	hlist_for_each_entry_rcu(sess, head, hash)
219		if (sess->port_id == port_id)
220			return sess;
221
222	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
223	if (!sess)
224		return ERR_PTR(-ENOMEM);
225
226	kref_init(&sess->kref); /* ref for table entry */
227	sess->tport = tport;
228	sess->port_id = port_id;
229
230	sess->se_sess = target_setup_session(se_tpg, TCM_FC_DEFAULT_TAGS,
231					     sizeof(struct ft_cmd),
232					     TARGET_PROT_NORMAL, &initiatorname[0],
233					     sess, ft_sess_alloc_cb);
234	if (IS_ERR(sess->se_sess)) {
235		int rc = PTR_ERR(sess->se_sess);
236		kfree(sess);
237		sess = ERR_PTR(rc);
238	}
239	return sess;
240}
241
242/*
243 * Unhash the session.
244 * Caller holds ft_lport_lock.
245 */
246static void ft_sess_unhash(struct ft_sess *sess)
247{
248	struct ft_tport *tport = sess->tport;
249
250	hlist_del_rcu(&sess->hash);
251	BUG_ON(!tport->sess_count);
252	tport->sess_count--;
253	sess->port_id = -1;
254	sess->params = 0;
255}
256
257/*
258 * Delete session from hash.
259 * Caller holds ft_lport_lock.
260 */
261static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
262{
263	struct hlist_head *head;
264	struct ft_sess *sess;
265
266	head = &tport->hash[ft_sess_hash(port_id)];
267	hlist_for_each_entry_rcu(sess, head, hash) {
268		if (sess->port_id == port_id) {
269			ft_sess_unhash(sess);
270			return sess;
271		}
272	}
273	return NULL;
274}
275
276static void ft_close_sess(struct ft_sess *sess)
277{
278	target_stop_session(sess->se_sess);
279	target_wait_for_sess_cmds(sess->se_sess);
280	ft_sess_put(sess);
281}
282
283/*
284 * Delete all sessions from tport.
285 * Caller holds ft_lport_lock.
286 */
287static void ft_sess_delete_all(struct ft_tport *tport)
288{
289	struct hlist_head *head;
290	struct ft_sess *sess;
291
292	for (head = tport->hash;
293	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
294		hlist_for_each_entry_rcu(sess, head, hash) {
295			ft_sess_unhash(sess);
296			ft_close_sess(sess);	/* release from table */
297		}
298	}
299}
300
301/*
302 * TCM ops for sessions.
303 */
304
305/*
306 * Remove session and send PRLO.
307 * This is called when the ACL is being deleted or queue depth is changing.
308 */
309void ft_sess_close(struct se_session *se_sess)
310{
311	struct ft_sess *sess = se_sess->fabric_sess_ptr;
312	u32 port_id;
313
314	mutex_lock(&ft_lport_lock);
315	port_id = sess->port_id;
316	if (port_id == -1) {
317		mutex_unlock(&ft_lport_lock);
318		return;
319	}
320	TFC_SESS_DBG(sess->tport->lport, "port_id %x close session\n", port_id);
321	ft_sess_unhash(sess);
322	mutex_unlock(&ft_lport_lock);
323	ft_close_sess(sess);
324	/* XXX Send LOGO or PRLO */
325	synchronize_rcu();		/* let transport deregister happen */
326}
327
328u32 ft_sess_get_index(struct se_session *se_sess)
329{
330	struct ft_sess *sess = se_sess->fabric_sess_ptr;
331
332	return sess->port_id;	/* XXX TBD probably not what is needed */
333}
334
335u32 ft_sess_get_port_name(struct se_session *se_sess,
336			  unsigned char *buf, u32 len)
337{
338	struct ft_sess *sess = se_sess->fabric_sess_ptr;
339
340	return ft_format_wwn(buf, len, sess->port_name);
341}
342
343/*
344 * libfc ops involving sessions.
345 */
346
347static int ft_prli_locked(struct fc_rport_priv *rdata, u32 spp_len,
348			  const struct fc_els_spp *rspp, struct fc_els_spp *spp)
349{
350	struct ft_tport *tport;
351	struct ft_sess *sess;
352	u32 fcp_parm;
353
354	tport = ft_tport_get(rdata->local_port);
355	if (!tport)
356		goto not_target;	/* not a target for this local port */
357
358	if (!rspp)
359		goto fill;
360
361	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
362		return FC_SPP_RESP_NO_PA;
363
364	/*
365	 * If both target and initiator bits are off, the SPP is invalid.
366	 */
367	fcp_parm = ntohl(rspp->spp_params);
368	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
369		return FC_SPP_RESP_INVL;
370
371	/*
372	 * Create session (image pair) only if requested by
373	 * EST_IMG_PAIR flag and if the requestor is an initiator.
374	 */
375	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
376		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
377		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
378			return FC_SPP_RESP_CONF;
379		sess = ft_sess_create(tport, rdata->ids.port_id, rdata);
380		if (IS_ERR(sess)) {
381			if (PTR_ERR(sess) == -EACCES) {
382				spp->spp_flags &= ~FC_SPP_EST_IMG_PAIR;
383				return FC_SPP_RESP_CONF;
384			} else
385				return FC_SPP_RESP_RES;
386		}
387		if (!sess->params)
388			rdata->prli_count++;
389		sess->params = fcp_parm;
390		sess->port_name = rdata->ids.port_name;
391		sess->max_frame = rdata->maxframe_size;
392
393		/* XXX TBD - clearing actions.  unit attn, see 4.10 */
394	}
395
396	/*
397	 * OR in our service parameters with other provider (initiator), if any.
398	 */
399fill:
400	fcp_parm = ntohl(spp->spp_params);
401	fcp_parm &= ~FCP_SPPF_RETRY;
402	spp->spp_params = htonl(fcp_parm | FCP_SPPF_TARG_FCN);
403	return FC_SPP_RESP_ACK;
404
405not_target:
406	fcp_parm = ntohl(spp->spp_params);
407	fcp_parm &= ~FCP_SPPF_TARG_FCN;
408	spp->spp_params = htonl(fcp_parm);
409	return 0;
410}
411
412/**
413 * ft_prli() - Handle incoming or outgoing PRLI for the FCP target
414 * @rdata: remote port private
415 * @spp_len: service parameter page length
416 * @rspp: received service parameter page (NULL for outgoing PRLI)
417 * @spp: response service parameter page
418 *
419 * Returns spp response code.
420 */
421static int ft_prli(struct fc_rport_priv *rdata, u32 spp_len,
422		   const struct fc_els_spp *rspp, struct fc_els_spp *spp)
423{
424	int ret;
425
426	mutex_lock(&ft_lport_lock);
427	ret = ft_prli_locked(rdata, spp_len, rspp, spp);
428	mutex_unlock(&ft_lport_lock);
429	TFC_SESS_DBG(rdata->local_port, "port_id %x flags %x ret %x\n",
430		     rdata->ids.port_id, rspp ? rspp->spp_flags : 0, ret);
431	return ret;
432}
433
434static void ft_sess_free(struct kref *kref)
435{
436	struct ft_sess *sess = container_of(kref, struct ft_sess, kref);
437
438	target_remove_session(sess->se_sess);
439	kfree_rcu(sess, rcu);
440}
441
442void ft_sess_put(struct ft_sess *sess)
443{
444	int sess_held = kref_read(&sess->kref);
445
446	BUG_ON(!sess_held);
447	kref_put(&sess->kref, ft_sess_free);
448}
449
450static void ft_prlo(struct fc_rport_priv *rdata)
451{
452	struct ft_sess *sess;
453	struct ft_tport *tport;
454
455	mutex_lock(&ft_lport_lock);
456	tport = rcu_dereference_protected(rdata->local_port->prov[FC_TYPE_FCP],
457					  lockdep_is_held(&ft_lport_lock));
458
459	if (!tport) {
460		mutex_unlock(&ft_lport_lock);
461		return;
462	}
463	sess = ft_sess_delete(tport, rdata->ids.port_id);
464	if (!sess) {
465		mutex_unlock(&ft_lport_lock);
466		return;
467	}
468	mutex_unlock(&ft_lport_lock);
469	ft_close_sess(sess);		/* release from table */
470	rdata->prli_count--;
471	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
472}
473
474/*
475 * Handle incoming FCP request.
476 * Caller has verified that the frame is type FCP.
477 */
478static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
479{
480	struct ft_sess *sess;
481	u32 sid = fc_frame_sid(fp);
482
483	TFC_SESS_DBG(lport, "recv sid %x\n", sid);
484
485	sess = ft_sess_get(lport, sid);
486	if (!sess) {
487		TFC_SESS_DBG(lport, "sid %x sess lookup failed\n", sid);
488		/* TBD XXX - if FCP_CMND, send PRLO */
489		fc_frame_free(fp);
490		return;
491	}
492	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
493}
494
495/*
496 * Provider ops for libfc.
497 */
498struct fc4_prov ft_prov = {
499	.prli = ft_prli,
500	.prlo = ft_prlo,
501	.recv = ft_recv,
502	.module = THIS_MODULE,
503};
504