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/rcupdate.h>
32#include <linux/rculist.h>
33#include <linux/kref.h>
34#include <asm/unaligned.h>
35#include <scsi/scsi.h>
36#include <scsi/scsi_host.h>
37#include <scsi/scsi_device.h>
38#include <scsi/scsi_cmnd.h>
39#include <scsi/libfc.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
48static void ft_sess_delete_all(struct ft_tport *);
49
50/*
51 * Lookup or allocate target local port.
52 * Caller holds ft_lport_lock.
53 */
54static struct ft_tport *ft_tport_get(struct fc_lport *lport)
55{
56	struct ft_tpg *tpg;
57	struct ft_tport *tport;
58	int i;
59
60	tport = rcu_dereference_protected(lport->prov[FC_TYPE_FCP],
61					  lockdep_is_held(&ft_lport_lock));
62	if (tport && tport->tpg)
63		return tport;
64
65	tpg = ft_lport_find_tpg(lport);
66	if (!tpg)
67		return NULL;
68
69	if (tport) {
70		tport->tpg = tpg;
71		tpg->tport = tport;
72		return tport;
73	}
74
75	tport = kzalloc(sizeof(*tport), GFP_KERNEL);
76	if (!tport)
77		return NULL;
78
79	tport->lport = lport;
80	tport->tpg = tpg;
81	tpg->tport = tport;
82	for (i = 0; i < FT_SESS_HASH_SIZE; i++)
83		INIT_HLIST_HEAD(&tport->hash[i]);
84
85	rcu_assign_pointer(lport->prov[FC_TYPE_FCP], tport);
86	return tport;
87}
88
89/*
90 * Delete a target local port.
91 * Caller holds ft_lport_lock.
92 */
93static void ft_tport_delete(struct ft_tport *tport)
94{
95	struct fc_lport *lport;
96	struct ft_tpg *tpg;
97
98	ft_sess_delete_all(tport);
99	lport = tport->lport;
100	BUG_ON(tport != lport->prov[FC_TYPE_FCP]);
101	RCU_INIT_POINTER(lport->prov[FC_TYPE_FCP], NULL);
102
103	tpg = tport->tpg;
104	if (tpg) {
105		tpg->tport = NULL;
106		tport->tpg = NULL;
107	}
108	kfree_rcu(tport, rcu);
109}
110
111/*
112 * Add local port.
113 * Called thru fc_lport_iterate().
114 */
115void ft_lport_add(struct fc_lport *lport, void *arg)
116{
117	mutex_lock(&ft_lport_lock);
118	ft_tport_get(lport);
119	mutex_unlock(&ft_lport_lock);
120}
121
122/*
123 * Delete local port.
124 * Called thru fc_lport_iterate().
125 */
126void ft_lport_del(struct fc_lport *lport, void *arg)
127{
128	struct ft_tport *tport;
129
130	mutex_lock(&ft_lport_lock);
131	tport = lport->prov[FC_TYPE_FCP];
132	if (tport)
133		ft_tport_delete(tport);
134	mutex_unlock(&ft_lport_lock);
135}
136
137/*
138 * Notification of local port change from libfc.
139 * Create or delete local port and associated tport.
140 */
141int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg)
142{
143	struct fc_lport *lport = arg;
144
145	switch (event) {
146	case FC_LPORT_EV_ADD:
147		ft_lport_add(lport, NULL);
148		break;
149	case FC_LPORT_EV_DEL:
150		ft_lport_del(lport, NULL);
151		break;
152	}
153	return NOTIFY_DONE;
154}
155
156/*
157 * Hash function for FC_IDs.
158 */
159static u32 ft_sess_hash(u32 port_id)
160{
161	return hash_32(port_id, FT_SESS_HASH_BITS);
162}
163
164/*
165 * Find session in local port.
166 * Sessions and hash lists are RCU-protected.
167 * A reference is taken which must be eventually freed.
168 */
169static struct ft_sess *ft_sess_get(struct fc_lport *lport, u32 port_id)
170{
171	struct ft_tport *tport;
172	struct hlist_head *head;
173	struct ft_sess *sess;
174
175	rcu_read_lock();
176	tport = rcu_dereference(lport->prov[FC_TYPE_FCP]);
177	if (!tport)
178		goto out;
179
180	head = &tport->hash[ft_sess_hash(port_id)];
181	hlist_for_each_entry_rcu(sess, head, hash) {
182		if (sess->port_id == port_id) {
183			kref_get(&sess->kref);
184			rcu_read_unlock();
185			pr_debug("port_id %x found %p\n", port_id, sess);
186			return sess;
187		}
188	}
189out:
190	rcu_read_unlock();
191	pr_debug("port_id %x not found\n", port_id);
192	return NULL;
193}
194
195/*
196 * Allocate session and enter it in the hash for the local port.
197 * Caller holds ft_lport_lock.
198 */
199static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
200				      struct ft_node_acl *acl)
201{
202	struct ft_sess *sess;
203	struct hlist_head *head;
204
205	head = &tport->hash[ft_sess_hash(port_id)];
206	hlist_for_each_entry_rcu(sess, head, hash)
207		if (sess->port_id == port_id)
208			return sess;
209
210	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
211	if (!sess)
212		return NULL;
213
214	sess->se_sess = transport_init_session_tags(TCM_FC_DEFAULT_TAGS,
215						    sizeof(struct ft_cmd),
216						    TARGET_PROT_NORMAL);
217	if (IS_ERR(sess->se_sess)) {
218		kfree(sess);
219		return NULL;
220	}
221	sess->se_sess->se_node_acl = &acl->se_node_acl;
222	sess->tport = tport;
223	sess->port_id = port_id;
224	kref_init(&sess->kref);	/* ref for table entry */
225	hlist_add_head_rcu(&sess->hash, head);
226	tport->sess_count++;
227
228	pr_debug("port_id %x sess %p\n", port_id, sess);
229
230	transport_register_session(&tport->tpg->se_tpg, &acl->se_node_acl,
231				   sess->se_sess, sess);
232	return sess;
233}
234
235/*
236 * Unhash the session.
237 * Caller holds ft_lport_lock.
238 */
239static void ft_sess_unhash(struct ft_sess *sess)
240{
241	struct ft_tport *tport = sess->tport;
242
243	hlist_del_rcu(&sess->hash);
244	BUG_ON(!tport->sess_count);
245	tport->sess_count--;
246	sess->port_id = -1;
247	sess->params = 0;
248}
249
250/*
251 * Delete session from hash.
252 * Caller holds ft_lport_lock.
253 */
254static struct ft_sess *ft_sess_delete(struct ft_tport *tport, u32 port_id)
255{
256	struct hlist_head *head;
257	struct ft_sess *sess;
258
259	head = &tport->hash[ft_sess_hash(port_id)];
260	hlist_for_each_entry_rcu(sess, head, hash) {
261		if (sess->port_id == port_id) {
262			ft_sess_unhash(sess);
263			return sess;
264		}
265	}
266	return NULL;
267}
268
269/*
270 * Delete all sessions from tport.
271 * Caller holds ft_lport_lock.
272 */
273static void ft_sess_delete_all(struct ft_tport *tport)
274{
275	struct hlist_head *head;
276	struct ft_sess *sess;
277
278	for (head = tport->hash;
279	     head < &tport->hash[FT_SESS_HASH_SIZE]; head++) {
280		hlist_for_each_entry_rcu(sess, head, hash) {
281			ft_sess_unhash(sess);
282			transport_deregister_session_configfs(sess->se_sess);
283			ft_sess_put(sess);	/* release from table */
284		}
285	}
286}
287
288/*
289 * TCM ops for sessions.
290 */
291
292/*
293 * Determine whether session is allowed to be shutdown in the current context.
294 * Returns non-zero if the session should be shutdown.
295 */
296int ft_sess_shutdown(struct se_session *se_sess)
297{
298	struct ft_sess *sess = se_sess->fabric_sess_ptr;
299
300	pr_debug("port_id %x\n", sess->port_id);
301	return 1;
302}
303
304/*
305 * Remove session and send PRLO.
306 * This is called when the ACL is being deleted or queue depth is changing.
307 */
308void ft_sess_close(struct se_session *se_sess)
309{
310	struct ft_sess *sess = se_sess->fabric_sess_ptr;
311	u32 port_id;
312
313	mutex_lock(&ft_lport_lock);
314	port_id = sess->port_id;
315	if (port_id == -1) {
316		mutex_unlock(&ft_lport_lock);
317		return;
318	}
319	pr_debug("port_id %x\n", port_id);
320	ft_sess_unhash(sess);
321	mutex_unlock(&ft_lport_lock);
322	transport_deregister_session_configfs(se_sess);
323	ft_sess_put(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	struct ft_node_acl *acl;
353	u32 fcp_parm;
354
355	tport = ft_tport_get(rdata->local_port);
356	if (!tport)
357		goto not_target;	/* not a target for this local port */
358
359	acl = ft_acl_get(tport->tpg, rdata);
360	if (!acl)
361		goto not_target;	/* no target for this remote */
362
363	if (!rspp)
364		goto fill;
365
366	if (rspp->spp_flags & (FC_SPP_OPA_VAL | FC_SPP_RPA_VAL))
367		return FC_SPP_RESP_NO_PA;
368
369	/*
370	 * If both target and initiator bits are off, the SPP is invalid.
371	 */
372	fcp_parm = ntohl(rspp->spp_params);
373	if (!(fcp_parm & (FCP_SPPF_INIT_FCN | FCP_SPPF_TARG_FCN)))
374		return FC_SPP_RESP_INVL;
375
376	/*
377	 * Create session (image pair) only if requested by
378	 * EST_IMG_PAIR flag and if the requestor is an initiator.
379	 */
380	if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR) {
381		spp->spp_flags |= FC_SPP_EST_IMG_PAIR;
382		if (!(fcp_parm & FCP_SPPF_INIT_FCN))
383			return FC_SPP_RESP_CONF;
384		sess = ft_sess_create(tport, rdata->ids.port_id, acl);
385		if (!sess)
386			return FC_SPP_RESP_RES;
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 * tcm_fcp_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	pr_debug("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	transport_deregister_session(sess->se_sess);
439	kfree_rcu(sess, rcu);
440}
441
442void ft_sess_put(struct ft_sess *sess)
443{
444	int sess_held = atomic_read(&sess->kref.refcount);
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	transport_deregister_session_configfs(sess->se_sess);
470	ft_sess_put(sess);		/* release from table */
471	rdata->prli_count--;
472	/* XXX TBD - clearing actions.  unit attn, see 4.10 */
473}
474
475/*
476 * Handle incoming FCP request.
477 * Caller has verified that the frame is type FCP.
478 */
479static void ft_recv(struct fc_lport *lport, struct fc_frame *fp)
480{
481	struct ft_sess *sess;
482	u32 sid = fc_frame_sid(fp);
483
484	pr_debug("sid %x\n", sid);
485
486	sess = ft_sess_get(lport, sid);
487	if (!sess) {
488		pr_debug("sid %x sess lookup failed\n", sid);
489		/* TBD XXX - if FCP_CMND, send PRLO */
490		fc_frame_free(fp);
491		return;
492	}
493	ft_recv_req(sess, fp);	/* must do ft_sess_put() */
494}
495
496/*
497 * Provider ops for libfc.
498 */
499struct fc4_prov ft_prov = {
500	.prli = ft_prli,
501	.prlo = ft_prlo,
502	.recv = ft_recv,
503	.module = THIS_MODULE,
504};
505