1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright(c) 2007 - 2008 Intel Corporation. All rights reserved.
5 * Maintained at www.Open-FCoE.org
11 * This block discovers all FC-4 remote ports, including FCP initiators. It
12 * also handles RSCN events and re-discovery if necessary.
18 * The disc mutex is can be locked when acquiring rport locks, but may not
19 * be held when acquiring the lport lock. Refer to fc_lport.c for more
23 #include <linux/timer.h>
24 #include <linux/slab.h>
25 #include <linux/err.h>
26 #include <linux/export.h>
27 #include <linux/list.h>
29 #include <asm/unaligned.h>
31 #include <scsi/fc/fc_gs.h>
33 #include <scsi/libfc.h>
37 #define FC_DISC_RETRY_LIMIT 3 /* max retries */
38 #define FC_DISC_RETRY_DELAY 500UL /* (msecs) delay */
40 static void fc_disc_gpn_ft_req(struct fc_disc *);
41 static void fc_disc_gpn_ft_resp(struct fc_seq *, struct fc_frame *, void *);
42 static void fc_disc_done(struct fc_disc *, enum fc_disc_event);
43 static void fc_disc_timeout(struct work_struct *);
44 static int fc_disc_single(struct fc_lport *, struct fc_disc_port *);
45 static void fc_disc_restart(struct fc_disc *);
48 * fc_disc_stop_rports() - Delete all the remote ports associated with the lport
49 * @disc: The discovery job to stop remote ports on
51 static void fc_disc_stop_rports(struct fc_disc *disc)
53 struct fc_rport_priv *rdata;
55 lockdep_assert_held(&disc->disc_mutex);
57 list_for_each_entry(rdata, &disc->rports, peers) {
58 if (kref_get_unless_zero(&rdata->kref)) {
59 fc_rport_logoff(rdata);
60 kref_put(&rdata->kref, fc_rport_destroy);
66 * fc_disc_recv_rscn_req() - Handle Registered State Change Notification (RSCN)
67 * @disc: The discovery object to which the RSCN applies
70 static void fc_disc_recv_rscn_req(struct fc_disc *disc, struct fc_frame *fp)
72 struct fc_lport *lport;
73 struct fc_els_rscn *rp;
74 struct fc_els_rscn_page *pp;
75 struct fc_seq_els_data rjt_data;
78 enum fc_els_rscn_addr_fmt fmt;
79 LIST_HEAD(disc_ports);
80 struct fc_disc_port *dp, *next;
82 lockdep_assert_held(&disc->disc_mutex);
84 lport = fc_disc_lport(disc);
86 FC_DISC_DBG(disc, "Received an RSCN event\n");
88 /* make sure the frame contains an RSCN message */
89 rp = fc_frame_payload_get(fp, sizeof(*rp));
92 /* make sure the page length is as expected (4 bytes) */
93 if (rp->rscn_page_len != sizeof(*pp))
95 /* get the RSCN payload length */
96 len = ntohs(rp->rscn_plen);
97 if (len < sizeof(*rp))
99 /* make sure the frame contains the expected payload */
100 rp = fc_frame_payload_get(fp, len);
103 /* payload must be a multiple of the RSCN page size */
105 if (len % sizeof(*pp))
108 for (pp = (void *)(rp + 1); len > 0; len -= sizeof(*pp), pp++) {
109 fmt = pp->rscn_page_flags >> ELS_RSCN_ADDR_FMT_BIT;
110 fmt &= ELS_RSCN_ADDR_FMT_MASK;
112 * if we get an address format other than port
113 * (area, domain, fabric), then do a full discovery
116 case ELS_ADDR_FMT_PORT:
117 FC_DISC_DBG(disc, "Port address format for port "
118 "(%6.6x)\n", ntoh24(pp->rscn_fid));
119 dp = kzalloc(sizeof(*dp), GFP_KERNEL);
125 dp->port_id = ntoh24(pp->rscn_fid);
126 list_add_tail(&dp->peers, &disc_ports);
128 case ELS_ADDR_FMT_AREA:
129 case ELS_ADDR_FMT_DOM:
130 case ELS_ADDR_FMT_FAB:
132 FC_DISC_DBG(disc, "Address format is (%d)\n", fmt);
137 fc_seq_els_rsp_send(fp, ELS_LS_ACC, NULL);
140 * If not doing a complete rediscovery, do GPN_ID on
141 * the individual ports mentioned in the list.
142 * If any of these get an error, do a full rediscovery.
143 * In any case, go through the list and free the entries.
145 list_for_each_entry_safe(dp, next, &disc_ports, peers) {
146 list_del(&dp->peers);
148 redisc = fc_disc_single(lport, dp);
152 FC_DISC_DBG(disc, "RSCN received: rediscovering\n");
153 fc_disc_restart(disc);
155 FC_DISC_DBG(disc, "RSCN received: not rediscovering. "
156 "redisc %d state %d in_prog %d\n",
157 redisc, lport->state, disc->pending);
162 FC_DISC_DBG(disc, "Received a bad RSCN frame\n");
163 rjt_data.reason = ELS_RJT_LOGIC;
164 rjt_data.explan = ELS_EXPL_NONE;
165 fc_seq_els_rsp_send(fp, ELS_LS_RJT, &rjt_data);
170 * fc_disc_recv_req() - Handle incoming requests
171 * @lport: The local port receiving the request
172 * @fp: The request frame
174 * Locking Note: This function is called from the EM and will lock
175 * the disc_mutex before calling the handler for the
178 static void fc_disc_recv_req(struct fc_lport *lport, struct fc_frame *fp)
181 struct fc_disc *disc = &lport->disc;
183 op = fc_frame_payload_op(fp);
186 mutex_lock(&disc->disc_mutex);
187 fc_disc_recv_rscn_req(disc, fp);
188 mutex_unlock(&disc->disc_mutex);
191 FC_DISC_DBG(disc, "Received an unsupported request, "
192 "the opcode is (%x)\n", op);
199 * fc_disc_restart() - Restart discovery
200 * @disc: The discovery object to be restarted
202 static void fc_disc_restart(struct fc_disc *disc)
204 lockdep_assert_held(&disc->disc_mutex);
206 if (!disc->disc_callback)
209 FC_DISC_DBG(disc, "Restarting discovery\n");
216 * Advance disc_id. This is an arbitrary non-zero number that will
217 * match the value in the fc_rport_priv after discovery for all
218 * freshly-discovered remote ports. Avoid wrapping to zero.
220 disc->disc_id = (disc->disc_id + 2) | 1;
221 disc->retry_count = 0;
222 fc_disc_gpn_ft_req(disc);
226 * fc_disc_start() - Start discovery on a local port
227 * @lport: The local port to have discovery started on
228 * @disc_callback: Callback function to be called when discovery is complete
230 static void fc_disc_start(void (*disc_callback)(struct fc_lport *,
232 struct fc_lport *lport)
234 struct fc_disc *disc = &lport->disc;
237 * At this point we may have a new disc job or an existing
238 * one. Either way, let's lock when we make changes to it
239 * and send the GPN_FT request.
241 mutex_lock(&disc->disc_mutex);
242 disc->disc_callback = disc_callback;
243 fc_disc_restart(disc);
244 mutex_unlock(&disc->disc_mutex);
248 * fc_disc_done() - Discovery has been completed
249 * @disc: The discovery context
250 * @event: The discovery completion status
252 static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event)
254 struct fc_lport *lport = fc_disc_lport(disc);
255 struct fc_rport_priv *rdata;
257 lockdep_assert_held(&disc->disc_mutex);
258 FC_DISC_DBG(disc, "Discovery complete\n");
261 if (disc->requested) {
262 fc_disc_restart(disc);
267 * Go through all remote ports. If they were found in the latest
268 * discovery, reverify or log them in. Otherwise, log them out.
269 * Skip ports which were never discovered. These are the dNS port
270 * and ports which were created by PLOGI.
272 * We don't need to use the _rcu variant here as the rport list
273 * is protected by the disc mutex which is already held on entry.
275 list_for_each_entry(rdata, &disc->rports, peers) {
276 if (!kref_get_unless_zero(&rdata->kref))
278 if (rdata->disc_id) {
279 if (rdata->disc_id == disc->disc_id)
280 fc_rport_login(rdata);
282 fc_rport_logoff(rdata);
284 kref_put(&rdata->kref, fc_rport_destroy);
286 mutex_unlock(&disc->disc_mutex);
287 disc->disc_callback(lport, event);
288 mutex_lock(&disc->disc_mutex);
292 * fc_disc_error() - Handle error on dNS request
293 * @disc: The discovery context
294 * @fp: The error code encoded as a frame pointer
296 static void fc_disc_error(struct fc_disc *disc, struct fc_frame *fp)
298 struct fc_lport *lport = fc_disc_lport(disc);
299 unsigned long delay = 0;
301 FC_DISC_DBG(disc, "Error %d, retries %d/%d\n",
302 PTR_ERR_OR_ZERO(fp), disc->retry_count,
303 FC_DISC_RETRY_LIMIT);
305 if (!fp || PTR_ERR(fp) == -FC_EX_TIMEOUT) {
307 * Memory allocation failure, or the exchange timed out,
310 if (disc->retry_count < FC_DISC_RETRY_LIMIT) {
311 /* go ahead and retry */
313 delay = msecs_to_jiffies(FC_DISC_RETRY_DELAY);
315 delay = msecs_to_jiffies(lport->e_d_tov);
317 /* timeout faster first time */
318 if (!disc->retry_count)
322 schedule_delayed_work(&disc->disc_work, delay);
324 fc_disc_done(disc, DISC_EV_FAILED);
325 } else if (PTR_ERR(fp) == -FC_EX_CLOSED) {
327 * if discovery fails due to lport reset, clear
328 * pending flag so that subsequent discovery can
336 * fc_disc_gpn_ft_req() - Send Get Port Names by FC-4 type (GPN_FT) request
337 * @disc: The discovery context
339 static void fc_disc_gpn_ft_req(struct fc_disc *disc)
342 struct fc_lport *lport = fc_disc_lport(disc);
344 lockdep_assert_held(&disc->disc_mutex);
346 WARN_ON(!fc_lport_test_ready(lport));
353 fp = fc_frame_alloc(lport,
354 sizeof(struct fc_ct_hdr) +
355 sizeof(struct fc_ns_gid_ft));
359 if (lport->tt.elsct_send(lport, 0, fp,
362 disc, 3 * lport->r_a_tov))
365 fc_disc_error(disc, NULL);
369 * fc_disc_gpn_ft_parse() - Parse the body of the dNS GPN_FT response.
370 * @disc: The discovery context
371 * @buf: The GPN_FT response buffer
372 * @len: The size of response buffer
374 * Goes through the list of IDs and names resulting from a request.
376 static int fc_disc_gpn_ft_parse(struct fc_disc *disc, void *buf, size_t len)
378 struct fc_lport *lport;
379 struct fc_gpn_ft_resp *np;
384 struct fc_rport_identifiers ids;
385 struct fc_rport_priv *rdata;
387 lport = fc_disc_lport(disc);
391 * Handle partial name record left over from previous call.
395 np = (struct fc_gpn_ft_resp *)bp;
396 tlen = disc->buf_len;
399 WARN_ON(tlen >= sizeof(*np));
400 plen = sizeof(*np) - tlen;
402 WARN_ON(plen >= sizeof(*np));
405 np = &disc->partial_buf;
406 memcpy((char *)np + tlen, bp, plen);
409 * Set bp so that the loop below will advance it to the
410 * first valid full name element.
415 disc->buf_len = (unsigned char) plen;
416 if (plen == sizeof(*np))
421 * Handle full name records, including the one filled from above.
422 * Normally, np == bp and plen == len, but from the partial case above,
423 * bp, len describe the overall buffer, and np, plen describe the
424 * partial buffer, which if would usually be full now.
425 * After the first time through the loop, things return to "normal".
427 while (plen >= sizeof(*np)) {
428 ids.port_id = ntoh24(np->fp_fid);
429 ids.port_name = ntohll(np->fp_wwpn);
431 if (ids.port_id != lport->port_id &&
432 ids.port_name != lport->wwpn) {
433 rdata = fc_rport_create(lport, ids.port_id);
435 rdata->ids.port_name = ids.port_name;
436 rdata->disc_id = disc->disc_id;
438 printk(KERN_WARNING "libfc: Failed to allocate "
439 "memory for the newly discovered port "
440 "(%6.6x)\n", ids.port_id);
445 if (np->fp_flags & FC_NS_FID_LAST) {
446 fc_disc_done(disc, DISC_EV_SUCCESS);
452 np = (struct fc_gpn_ft_resp *)bp;
457 * Save any partial record at the end of the buffer for next time.
459 if (error == 0 && len > 0 && len < sizeof(*np)) {
460 if (np != &disc->partial_buf) {
461 FC_DISC_DBG(disc, "Partial buffer remains "
463 memcpy(&disc->partial_buf, np, len);
465 disc->buf_len = (unsigned char) len;
471 * fc_disc_timeout() - Handler for discovery timeouts
472 * @work: Structure holding discovery context that needs to retry discovery
474 static void fc_disc_timeout(struct work_struct *work)
476 struct fc_disc *disc = container_of(work,
479 mutex_lock(&disc->disc_mutex);
480 fc_disc_gpn_ft_req(disc);
481 mutex_unlock(&disc->disc_mutex);
485 * fc_disc_gpn_ft_resp() - Handle a response frame from Get Port Names (GPN_FT)
486 * @sp: The sequence that the GPN_FT response was received on
487 * @fp: The GPN_FT response frame
488 * @disc_arg: The discovery context
490 * Locking Note: This function is called without disc mutex held, and
491 * should do all its processing with the mutex held
493 static void fc_disc_gpn_ft_resp(struct fc_seq *sp, struct fc_frame *fp,
496 struct fc_disc *disc = disc_arg;
497 struct fc_ct_hdr *cp;
498 struct fc_frame_header *fh;
499 enum fc_disc_event event = DISC_EV_NONE;
500 unsigned int seq_cnt;
504 mutex_lock(&disc->disc_mutex);
505 FC_DISC_DBG(disc, "Received a GPN_FT response\n");
508 fc_disc_error(disc, fp);
509 mutex_unlock(&disc->disc_mutex);
513 WARN_ON(!fc_frame_is_linear(fp)); /* buffer must be contiguous */
514 fh = fc_frame_header_get(fp);
515 len = fr_len(fp) - sizeof(*fh);
516 seq_cnt = ntohs(fh->fh_seq_cnt);
517 if (fr_sof(fp) == FC_SOF_I3 && seq_cnt == 0 && disc->seq_count == 0) {
518 cp = fc_frame_payload_get(fp, sizeof(*cp));
520 FC_DISC_DBG(disc, "GPN_FT response too short, len %d\n",
522 event = DISC_EV_FAILED;
523 } else if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
525 /* Accepted, parse the response. */
527 error = fc_disc_gpn_ft_parse(disc, cp + 1, len);
528 } else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
529 FC_DISC_DBG(disc, "GPN_FT rejected reason %x exp %x "
530 "(check zoning)\n", cp->ct_reason,
532 event = DISC_EV_FAILED;
533 if (cp->ct_reason == FC_FS_RJT_UNABL &&
534 cp->ct_explan == FC_FS_EXP_FTNR)
535 event = DISC_EV_SUCCESS;
537 FC_DISC_DBG(disc, "GPN_FT unexpected response code "
538 "%x\n", ntohs(cp->ct_cmd));
539 event = DISC_EV_FAILED;
541 } else if (fr_sof(fp) == FC_SOF_N3 && seq_cnt == disc->seq_count) {
542 error = fc_disc_gpn_ft_parse(disc, fh + 1, len);
544 FC_DISC_DBG(disc, "GPN_FT unexpected frame - out of sequence? "
545 "seq_cnt %x expected %x sof %x eof %x\n",
546 seq_cnt, disc->seq_count, fr_sof(fp), fr_eof(fp));
547 event = DISC_EV_FAILED;
550 fc_disc_error(disc, ERR_PTR(error));
551 else if (event != DISC_EV_NONE)
552 fc_disc_done(disc, event);
554 mutex_unlock(&disc->disc_mutex);
558 * fc_disc_gpn_id_resp() - Handle a response frame from Get Port Names (GPN_ID)
559 * @sp: The sequence the GPN_ID is on
560 * @fp: The response frame
561 * @rdata_arg: The remote port that sent the GPN_ID response
563 * Locking Note: This function is called without disc mutex held.
565 static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp,
568 struct fc_rport_priv *rdata = rdata_arg;
569 struct fc_rport_priv *new_rdata;
570 struct fc_lport *lport;
571 struct fc_disc *disc;
572 struct fc_ct_hdr *cp;
573 struct fc_ns_gid_pn *pn;
576 lport = rdata->local_port;
579 if (PTR_ERR(fp) == -FC_EX_CLOSED)
582 mutex_lock(&disc->disc_mutex);
583 fc_disc_restart(disc);
584 mutex_unlock(&disc->disc_mutex);
588 cp = fc_frame_payload_get(fp, sizeof(*cp));
591 if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
592 if (fr_len(fp) < sizeof(struct fc_frame_header) +
593 sizeof(*cp) + sizeof(*pn))
595 pn = (struct fc_ns_gid_pn *)(cp + 1);
596 port_name = get_unaligned_be64(&pn->fn_wwpn);
597 mutex_lock(&rdata->rp_mutex);
598 if (rdata->ids.port_name == -1)
599 rdata->ids.port_name = port_name;
600 else if (rdata->ids.port_name != port_name) {
601 FC_DISC_DBG(disc, "GPN_ID accepted. WWPN changed. "
602 "Port-id %6.6x wwpn %16.16llx\n",
603 rdata->ids.port_id, port_name);
604 mutex_unlock(&rdata->rp_mutex);
605 fc_rport_logoff(rdata);
606 mutex_lock(&lport->disc.disc_mutex);
607 new_rdata = fc_rport_create(lport, rdata->ids.port_id);
608 mutex_unlock(&lport->disc.disc_mutex);
610 new_rdata->disc_id = disc->disc_id;
611 fc_rport_login(new_rdata);
615 rdata->disc_id = disc->disc_id;
616 mutex_unlock(&rdata->rp_mutex);
617 fc_rport_login(rdata);
618 } else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
619 FC_DISC_DBG(disc, "GPN_ID rejected reason %x exp %x\n",
620 cp->ct_reason, cp->ct_explan);
621 fc_rport_logoff(rdata);
623 FC_DISC_DBG(disc, "GPN_ID unexpected response code %x\n",
626 mutex_lock(&disc->disc_mutex);
627 fc_disc_restart(disc);
628 mutex_unlock(&disc->disc_mutex);
633 kref_put(&rdata->kref, fc_rport_destroy);
637 * fc_disc_gpn_id_req() - Send Get Port Names by ID (GPN_ID) request
638 * @lport: The local port to initiate discovery on
639 * @rdata: remote port private data
641 * On failure, an error code is returned.
643 static int fc_disc_gpn_id_req(struct fc_lport *lport,
644 struct fc_rport_priv *rdata)
648 lockdep_assert_held(&lport->disc.disc_mutex);
649 fp = fc_frame_alloc(lport, sizeof(struct fc_ct_hdr) +
650 sizeof(struct fc_ns_fid));
653 if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, FC_NS_GPN_ID,
654 fc_disc_gpn_id_resp, rdata,
657 kref_get(&rdata->kref);
662 * fc_disc_single() - Discover the directory information for a single target
663 * @lport: The local port the remote port is associated with
664 * @dp: The port to rediscover
666 static int fc_disc_single(struct fc_lport *lport, struct fc_disc_port *dp)
668 struct fc_rport_priv *rdata;
670 lockdep_assert_held(&lport->disc.disc_mutex);
672 rdata = fc_rport_create(lport, dp->port_id);
676 return fc_disc_gpn_id_req(lport, rdata);
680 * fc_disc_stop() - Stop discovery for a given lport
681 * @lport: The local port that discovery should stop on
683 static void fc_disc_stop(struct fc_lport *lport)
685 struct fc_disc *disc = &lport->disc;
688 cancel_delayed_work_sync(&disc->disc_work);
689 mutex_lock(&disc->disc_mutex);
690 fc_disc_stop_rports(disc);
691 mutex_unlock(&disc->disc_mutex);
695 * fc_disc_stop_final() - Stop discovery for a given lport
696 * @lport: The lport that discovery should stop on
698 * This function will block until discovery has been
699 * completely stopped and all rports have been deleted.
701 static void fc_disc_stop_final(struct fc_lport *lport)
704 fc_rport_flush_queue();
708 * fc_disc_config() - Configure the discovery layer for a local port
709 * @lport: The local port that needs the discovery layer to be configured
710 * @priv: Private data structre for users of the discovery layer
712 void fc_disc_config(struct fc_lport *lport, void *priv)
714 struct fc_disc *disc;
716 if (!lport->tt.disc_start)
717 lport->tt.disc_start = fc_disc_start;
719 if (!lport->tt.disc_stop)
720 lport->tt.disc_stop = fc_disc_stop;
722 if (!lport->tt.disc_stop_final)
723 lport->tt.disc_stop_final = fc_disc_stop_final;
725 if (!lport->tt.disc_recv_req)
726 lport->tt.disc_recv_req = fc_disc_recv_req;
732 EXPORT_SYMBOL(fc_disc_config);
735 * fc_disc_init() - Initialize the discovery layer for a local port
736 * @lport: The local port that needs the discovery layer to be initialized
738 void fc_disc_init(struct fc_lport *lport)
740 struct fc_disc *disc = &lport->disc;
742 INIT_DELAYED_WORK(&disc->disc_work, fc_disc_timeout);
743 mutex_init(&disc->disc_mutex);
744 INIT_LIST_HEAD(&disc->rports);
746 EXPORT_SYMBOL(fc_disc_init);