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