1 /* 2 * Copyright(c) 2007 - 2008 Intel Corporation. All rights reserved. 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 * Maintained at www.Open-FCoE.org 18 */ 19 20 /* 21 * Target Discovery 22 * 23 * This block discovers all FC-4 remote ports, including FCP initiators. It 24 * also handles RSCN events and re-discovery if necessary. 25 */ 26 27 /* 28 * DISC LOCKING 29 * 30 * The disc mutex is can be locked when acquiring rport locks, but may not 31 * be held when acquiring the lport lock. Refer to fc_lport.c for more 32 * details. 33 */ 34 35 #include <linux/timer.h> 36 #include <linux/err.h> 37 #include <asm/unaligned.h> 38 39 #include <scsi/fc/fc_gs.h> 40 41 #include <scsi/libfc.h> 42 43 #define FC_DISC_RETRY_LIMIT 3 /* max retries */ 44 #define FC_DISC_RETRY_DELAY 500UL /* (msecs) delay */ 45 46 static void fc_disc_gpn_ft_req(struct fc_disc *); 47 static void fc_disc_gpn_ft_resp(struct fc_seq *, struct fc_frame *, void *); 48 static void fc_disc_done(struct fc_disc *, enum fc_disc_event); 49 static void fc_disc_timeout(struct work_struct *); 50 static void fc_disc_single(struct fc_disc *, struct fc_disc_port *); 51 static void fc_disc_restart(struct fc_disc *); 52 53 /** 54 * fc_disc_stop_rports() - delete all the remote ports associated with the lport 55 * @disc: The discovery job to stop rports on 56 * 57 * Locking Note: This function expects that the lport mutex is locked before 58 * calling it. 59 */ 60 void fc_disc_stop_rports(struct fc_disc *disc) 61 { 62 struct fc_lport *lport; 63 struct fc_rport_priv *rdata, *next; 64 65 lport = disc->lport; 66 67 mutex_lock(&disc->disc_mutex); 68 list_for_each_entry_safe(rdata, next, &disc->rports, peers) 69 lport->tt.rport_logoff(rdata); 70 mutex_unlock(&disc->disc_mutex); 71 } 72 73 /** 74 * fc_disc_recv_rscn_req() - Handle Registered State Change Notification (RSCN) 75 * @sp: Current sequence of the RSCN exchange 76 * @fp: RSCN Frame 77 * @lport: Fibre Channel host port instance 78 * 79 * Locking Note: This function expects that the disc_mutex is locked 80 * before it is called. 81 */ 82 static void fc_disc_recv_rscn_req(struct fc_seq *sp, struct fc_frame *fp, 83 struct fc_disc *disc) 84 { 85 struct fc_lport *lport; 86 struct fc_rport_priv *rdata; 87 struct fc_els_rscn *rp; 88 struct fc_els_rscn_page *pp; 89 struct fc_seq_els_data rjt_data; 90 unsigned int len; 91 int redisc = 0; 92 enum fc_els_rscn_ev_qual ev_qual; 93 enum fc_els_rscn_addr_fmt fmt; 94 LIST_HEAD(disc_ports); 95 struct fc_disc_port *dp, *next; 96 97 lport = disc->lport; 98 99 FC_DISC_DBG(disc, "Received an RSCN event\n"); 100 101 /* make sure the frame contains an RSCN message */ 102 rp = fc_frame_payload_get(fp, sizeof(*rp)); 103 if (!rp) 104 goto reject; 105 /* make sure the page length is as expected (4 bytes) */ 106 if (rp->rscn_page_len != sizeof(*pp)) 107 goto reject; 108 /* get the RSCN payload length */ 109 len = ntohs(rp->rscn_plen); 110 if (len < sizeof(*rp)) 111 goto reject; 112 /* make sure the frame contains the expected payload */ 113 rp = fc_frame_payload_get(fp, len); 114 if (!rp) 115 goto reject; 116 /* payload must be a multiple of the RSCN page size */ 117 len -= sizeof(*rp); 118 if (len % sizeof(*pp)) 119 goto reject; 120 121 for (pp = (void *)(rp + 1); len > 0; len -= sizeof(*pp), pp++) { 122 ev_qual = pp->rscn_page_flags >> ELS_RSCN_EV_QUAL_BIT; 123 ev_qual &= ELS_RSCN_EV_QUAL_MASK; 124 fmt = pp->rscn_page_flags >> ELS_RSCN_ADDR_FMT_BIT; 125 fmt &= ELS_RSCN_ADDR_FMT_MASK; 126 /* 127 * if we get an address format other than port 128 * (area, domain, fabric), then do a full discovery 129 */ 130 switch (fmt) { 131 case ELS_ADDR_FMT_PORT: 132 FC_DISC_DBG(disc, "Port address format for port " 133 "(%6x)\n", ntoh24(pp->rscn_fid)); 134 dp = kzalloc(sizeof(*dp), GFP_KERNEL); 135 if (!dp) { 136 redisc = 1; 137 break; 138 } 139 dp->lp = lport; 140 dp->ids.port_id = ntoh24(pp->rscn_fid); 141 dp->ids.port_name = -1; 142 dp->ids.node_name = -1; 143 dp->ids.roles = FC_RPORT_ROLE_UNKNOWN; 144 list_add_tail(&dp->peers, &disc_ports); 145 break; 146 case ELS_ADDR_FMT_AREA: 147 case ELS_ADDR_FMT_DOM: 148 case ELS_ADDR_FMT_FAB: 149 default: 150 FC_DISC_DBG(disc, "Address format is (%d)\n", fmt); 151 redisc = 1; 152 break; 153 } 154 } 155 lport->tt.seq_els_rsp_send(sp, ELS_LS_ACC, NULL); 156 if (redisc) { 157 FC_DISC_DBG(disc, "RSCN received: rediscovering\n"); 158 fc_disc_restart(disc); 159 } else { 160 FC_DISC_DBG(disc, "RSCN received: not rediscovering. " 161 "redisc %d state %d in_prog %d\n", 162 redisc, lport->state, disc->pending); 163 list_for_each_entry_safe(dp, next, &disc_ports, peers) { 164 list_del(&dp->peers); 165 rdata = lport->tt.rport_lookup(lport, dp->ids.port_id); 166 if (rdata) { 167 lport->tt.rport_logoff(rdata); 168 } 169 fc_disc_single(disc, dp); 170 } 171 } 172 fc_frame_free(fp); 173 return; 174 reject: 175 FC_DISC_DBG(disc, "Received a bad RSCN frame\n"); 176 rjt_data.fp = NULL; 177 rjt_data.reason = ELS_RJT_LOGIC; 178 rjt_data.explan = ELS_EXPL_NONE; 179 lport->tt.seq_els_rsp_send(sp, ELS_LS_RJT, &rjt_data); 180 fc_frame_free(fp); 181 } 182 183 /** 184 * fc_disc_recv_req() - Handle incoming requests 185 * @sp: Current sequence of the request exchange 186 * @fp: The frame 187 * @lport: The FC local port 188 * 189 * Locking Note: This function is called from the EM and will lock 190 * the disc_mutex before calling the handler for the 191 * request. 192 */ 193 static void fc_disc_recv_req(struct fc_seq *sp, struct fc_frame *fp, 194 struct fc_lport *lport) 195 { 196 u8 op; 197 struct fc_disc *disc = &lport->disc; 198 199 op = fc_frame_payload_op(fp); 200 switch (op) { 201 case ELS_RSCN: 202 mutex_lock(&disc->disc_mutex); 203 fc_disc_recv_rscn_req(sp, fp, disc); 204 mutex_unlock(&disc->disc_mutex); 205 break; 206 default: 207 FC_DISC_DBG(disc, "Received an unsupported request, " 208 "the opcode is (%x)\n", op); 209 break; 210 } 211 } 212 213 /** 214 * fc_disc_restart() - Restart discovery 215 * @lport: FC discovery context 216 * 217 * Locking Note: This function expects that the disc mutex 218 * is already locked. 219 */ 220 static void fc_disc_restart(struct fc_disc *disc) 221 { 222 FC_DISC_DBG(disc, "Restarting discovery\n"); 223 224 disc->requested = 1; 225 if (disc->pending) 226 return; 227 228 /* 229 * Advance disc_id. This is an arbitrary non-zero number that will 230 * match the value in the fc_rport_priv after discovery for all 231 * freshly-discovered remote ports. Avoid wrapping to zero. 232 */ 233 disc->disc_id = (disc->disc_id + 2) | 1; 234 disc->retry_count = 0; 235 fc_disc_gpn_ft_req(disc); 236 } 237 238 /** 239 * fc_disc_start() - Fibre Channel Target discovery 240 * @lport: FC local port 241 * @disc_callback: function to be called when discovery is complete 242 */ 243 static void fc_disc_start(void (*disc_callback)(struct fc_lport *, 244 enum fc_disc_event), 245 struct fc_lport *lport) 246 { 247 struct fc_disc *disc = &lport->disc; 248 249 /* 250 * At this point we may have a new disc job or an existing 251 * one. Either way, let's lock when we make changes to it 252 * and send the GPN_FT request. 253 */ 254 mutex_lock(&disc->disc_mutex); 255 disc->disc_callback = disc_callback; 256 fc_disc_restart(disc); 257 mutex_unlock(&disc->disc_mutex); 258 } 259 260 /** 261 * fc_disc_done() - Discovery has been completed 262 * @disc: FC discovery context 263 * @event: discovery completion status 264 * 265 * Locking Note: This function expects that the disc mutex is locked before 266 * it is called. The discovery callback is then made with the lock released, 267 * and the lock is re-taken before returning from this function 268 */ 269 static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event) 270 { 271 struct fc_lport *lport = disc->lport; 272 struct fc_rport_priv *rdata; 273 274 FC_DISC_DBG(disc, "Discovery complete\n"); 275 276 disc->pending = 0; 277 if (disc->requested) { 278 fc_disc_restart(disc); 279 return; 280 } 281 282 /* 283 * Go through all remote ports. If they were found in the latest 284 * discovery, reverify or log them in. Otherwise, log them out. 285 * Skip ports which were never discovered. These are the dNS port 286 * and ports which were created by PLOGI. 287 */ 288 list_for_each_entry(rdata, &disc->rports, peers) { 289 if (!rdata->disc_id) 290 continue; 291 if (rdata->disc_id == disc->disc_id) 292 lport->tt.rport_login(rdata); 293 else 294 lport->tt.rport_logoff(rdata); 295 } 296 297 mutex_unlock(&disc->disc_mutex); 298 disc->disc_callback(lport, event); 299 mutex_lock(&disc->disc_mutex); 300 } 301 302 /** 303 * fc_disc_error() - Handle error on dNS request 304 * @disc: FC discovery context 305 * @fp: The frame pointer 306 */ 307 static void fc_disc_error(struct fc_disc *disc, struct fc_frame *fp) 308 { 309 struct fc_lport *lport = disc->lport; 310 unsigned long delay = 0; 311 312 FC_DISC_DBG(disc, "Error %ld, retries %d/%d\n", 313 PTR_ERR(fp), disc->retry_count, 314 FC_DISC_RETRY_LIMIT); 315 316 if (!fp || PTR_ERR(fp) == -FC_EX_TIMEOUT) { 317 /* 318 * Memory allocation failure, or the exchange timed out, 319 * retry after delay. 320 */ 321 if (disc->retry_count < FC_DISC_RETRY_LIMIT) { 322 /* go ahead and retry */ 323 if (!fp) 324 delay = msecs_to_jiffies(FC_DISC_RETRY_DELAY); 325 else { 326 delay = msecs_to_jiffies(lport->e_d_tov); 327 328 /* timeout faster first time */ 329 if (!disc->retry_count) 330 delay /= 4; 331 } 332 disc->retry_count++; 333 schedule_delayed_work(&disc->disc_work, delay); 334 } else 335 fc_disc_done(disc, DISC_EV_FAILED); 336 } 337 } 338 339 /** 340 * fc_disc_gpn_ft_req() - Send Get Port Names by FC-4 type (GPN_FT) request 341 * @lport: FC discovery context 342 * 343 * Locking Note: This function expects that the disc_mutex is locked 344 * before it is called. 345 */ 346 static void fc_disc_gpn_ft_req(struct fc_disc *disc) 347 { 348 struct fc_frame *fp; 349 struct fc_lport *lport = disc->lport; 350 351 WARN_ON(!fc_lport_test_ready(lport)); 352 353 disc->pending = 1; 354 disc->requested = 0; 355 356 disc->buf_len = 0; 357 disc->seq_count = 0; 358 fp = fc_frame_alloc(lport, 359 sizeof(struct fc_ct_hdr) + 360 sizeof(struct fc_ns_gid_ft)); 361 if (!fp) 362 goto err; 363 364 if (lport->tt.elsct_send(lport, 0, fp, 365 FC_NS_GPN_FT, 366 fc_disc_gpn_ft_resp, 367 disc, lport->e_d_tov)) 368 return; 369 err: 370 fc_disc_error(disc, fp); 371 } 372 373 /** 374 * fc_disc_gpn_ft_parse() - Parse the body of the dNS GPN_FT response. 375 * @lport: Fibre Channel host port instance 376 * @buf: GPN_FT response buffer 377 * @len: size of response buffer 378 * 379 * Goes through the list of IDs and names resulting from a request. 380 */ 381 static int fc_disc_gpn_ft_parse(struct fc_disc *disc, void *buf, size_t len) 382 { 383 struct fc_lport *lport; 384 struct fc_gpn_ft_resp *np; 385 char *bp; 386 size_t plen; 387 size_t tlen; 388 int error = 0; 389 struct fc_rport_identifiers ids; 390 struct fc_rport_priv *rdata; 391 392 lport = disc->lport; 393 disc->seq_count++; 394 395 /* 396 * Handle partial name record left over from previous call. 397 */ 398 bp = buf; 399 plen = len; 400 np = (struct fc_gpn_ft_resp *)bp; 401 tlen = disc->buf_len; 402 disc->buf_len = 0; 403 if (tlen) { 404 WARN_ON(tlen >= sizeof(*np)); 405 plen = sizeof(*np) - tlen; 406 WARN_ON(plen <= 0); 407 WARN_ON(plen >= sizeof(*np)); 408 if (plen > len) 409 plen = len; 410 np = &disc->partial_buf; 411 memcpy((char *)np + tlen, bp, plen); 412 413 /* 414 * Set bp so that the loop below will advance it to the 415 * first valid full name element. 416 */ 417 bp -= tlen; 418 len += tlen; 419 plen += tlen; 420 disc->buf_len = (unsigned char) plen; 421 if (plen == sizeof(*np)) 422 disc->buf_len = 0; 423 } 424 425 /* 426 * Handle full name records, including the one filled from above. 427 * Normally, np == bp and plen == len, but from the partial case above, 428 * bp, len describe the overall buffer, and np, plen describe the 429 * partial buffer, which if would usually be full now. 430 * After the first time through the loop, things return to "normal". 431 */ 432 while (plen >= sizeof(*np)) { 433 ids.port_id = ntoh24(np->fp_fid); 434 ids.port_name = ntohll(np->fp_wwpn); 435 ids.node_name = -1; 436 ids.roles = FC_RPORT_ROLE_UNKNOWN; 437 438 if (ids.port_id != fc_host_port_id(lport->host) && 439 ids.port_name != lport->wwpn) { 440 rdata = lport->tt.rport_create(lport, &ids); 441 if (rdata) 442 rdata->disc_id = disc->disc_id; 443 else { 444 printk(KERN_WARNING "libfc: Failed to allocate " 445 "memory for the newly discovered port " 446 "(%6x)\n", ids.port_id); 447 error = -ENOMEM; 448 } 449 } 450 451 if (np->fp_flags & FC_NS_FID_LAST) { 452 fc_disc_done(disc, DISC_EV_SUCCESS); 453 len = 0; 454 break; 455 } 456 len -= sizeof(*np); 457 bp += sizeof(*np); 458 np = (struct fc_gpn_ft_resp *)bp; 459 plen = len; 460 } 461 462 /* 463 * Save any partial record at the end of the buffer for next time. 464 */ 465 if (error == 0 && len > 0 && len < sizeof(*np)) { 466 if (np != &disc->partial_buf) { 467 FC_DISC_DBG(disc, "Partial buffer remains " 468 "for discovery\n"); 469 memcpy(&disc->partial_buf, np, len); 470 } 471 disc->buf_len = (unsigned char) len; 472 } 473 return error; 474 } 475 476 /** 477 * fc_disc_timeout() - Retry handler for the disc component 478 * @work: Structure holding disc obj that needs retry discovery 479 * 480 * Handle retry of memory allocation for remote ports. 481 */ 482 static void fc_disc_timeout(struct work_struct *work) 483 { 484 struct fc_disc *disc = container_of(work, 485 struct fc_disc, 486 disc_work.work); 487 mutex_lock(&disc->disc_mutex); 488 fc_disc_gpn_ft_req(disc); 489 mutex_unlock(&disc->disc_mutex); 490 } 491 492 /** 493 * fc_disc_gpn_ft_resp() - Handle a response frame from Get Port Names (GPN_FT) 494 * @sp: Current sequence of GPN_FT exchange 495 * @fp: response frame 496 * @lp_arg: Fibre Channel host port instance 497 * 498 * Locking Note: This function is called without disc mutex held, and 499 * should do all its processing with the mutex held 500 */ 501 static void fc_disc_gpn_ft_resp(struct fc_seq *sp, struct fc_frame *fp, 502 void *disc_arg) 503 { 504 struct fc_disc *disc = disc_arg; 505 struct fc_ct_hdr *cp; 506 struct fc_frame_header *fh; 507 enum fc_disc_event event = DISC_EV_NONE; 508 unsigned int seq_cnt; 509 unsigned int len; 510 int error = 0; 511 512 mutex_lock(&disc->disc_mutex); 513 FC_DISC_DBG(disc, "Received a GPN_FT response\n"); 514 515 if (IS_ERR(fp)) { 516 fc_disc_error(disc, fp); 517 mutex_unlock(&disc->disc_mutex); 518 return; 519 } 520 521 WARN_ON(!fc_frame_is_linear(fp)); /* buffer must be contiguous */ 522 fh = fc_frame_header_get(fp); 523 len = fr_len(fp) - sizeof(*fh); 524 seq_cnt = ntohs(fh->fh_seq_cnt); 525 if (fr_sof(fp) == FC_SOF_I3 && seq_cnt == 0 && disc->seq_count == 0) { 526 cp = fc_frame_payload_get(fp, sizeof(*cp)); 527 if (!cp) { 528 FC_DISC_DBG(disc, "GPN_FT response too short, len %d\n", 529 fr_len(fp)); 530 event = DISC_EV_FAILED; 531 } else if (ntohs(cp->ct_cmd) == FC_FS_ACC) { 532 533 /* Accepted, parse the response. */ 534 len -= sizeof(*cp); 535 error = fc_disc_gpn_ft_parse(disc, cp + 1, len); 536 } else if (ntohs(cp->ct_cmd) == FC_FS_RJT) { 537 FC_DISC_DBG(disc, "GPN_FT rejected reason %x exp %x " 538 "(check zoning)\n", cp->ct_reason, 539 cp->ct_explan); 540 event = DISC_EV_FAILED; 541 if (cp->ct_reason == FC_FS_RJT_UNABL && 542 cp->ct_explan == FC_FS_EXP_FTNR) 543 event = DISC_EV_SUCCESS; 544 } else { 545 FC_DISC_DBG(disc, "GPN_FT unexpected response code " 546 "%x\n", ntohs(cp->ct_cmd)); 547 event = DISC_EV_FAILED; 548 } 549 } else if (fr_sof(fp) == FC_SOF_N3 && seq_cnt == disc->seq_count) { 550 error = fc_disc_gpn_ft_parse(disc, fh + 1, len); 551 } else { 552 FC_DISC_DBG(disc, "GPN_FT unexpected frame - out of sequence? " 553 "seq_cnt %x expected %x sof %x eof %x\n", 554 seq_cnt, disc->seq_count, fr_sof(fp), fr_eof(fp)); 555 event = DISC_EV_FAILED; 556 } 557 if (error) 558 fc_disc_error(disc, fp); 559 else if (event != DISC_EV_NONE) 560 fc_disc_done(disc, event); 561 fc_frame_free(fp); 562 mutex_unlock(&disc->disc_mutex); 563 } 564 565 /** 566 * fc_disc_single() - Discover the directory information for a single target 567 * @lport: FC local port 568 * @dp: The port to rediscover 569 * 570 * Locking Note: This function expects that the disc_mutex is locked 571 * before it is called. 572 */ 573 static void fc_disc_single(struct fc_disc *disc, struct fc_disc_port *dp) 574 { 575 struct fc_lport *lport; 576 struct fc_rport_priv *rdata; 577 578 lport = disc->lport; 579 580 if (dp->ids.port_id == fc_host_port_id(lport->host)) 581 goto out; 582 583 rdata = lport->tt.rport_create(lport, &dp->ids); 584 if (rdata) { 585 rdata->disc_id = disc->disc_id; 586 kfree(dp); 587 lport->tt.rport_login(rdata); 588 } 589 return; 590 out: 591 kfree(dp); 592 } 593 594 /** 595 * fc_disc_stop() - Stop discovery for a given lport 596 * @lport: The lport that discovery should stop for 597 */ 598 void fc_disc_stop(struct fc_lport *lport) 599 { 600 struct fc_disc *disc = &lport->disc; 601 602 if (disc) { 603 cancel_delayed_work_sync(&disc->disc_work); 604 fc_disc_stop_rports(disc); 605 } 606 } 607 608 /** 609 * fc_disc_stop_final() - Stop discovery for a given lport 610 * @lport: The lport that discovery should stop for 611 * 612 * This function will block until discovery has been 613 * completely stopped and all rports have been deleted. 614 */ 615 void fc_disc_stop_final(struct fc_lport *lport) 616 { 617 fc_disc_stop(lport); 618 lport->tt.rport_flush_queue(); 619 } 620 621 /** 622 * fc_disc_init() - Initialize the discovery block 623 * @lport: FC local port 624 */ 625 int fc_disc_init(struct fc_lport *lport) 626 { 627 struct fc_disc *disc; 628 629 if (!lport->tt.disc_start) 630 lport->tt.disc_start = fc_disc_start; 631 632 if (!lport->tt.disc_stop) 633 lport->tt.disc_stop = fc_disc_stop; 634 635 if (!lport->tt.disc_stop_final) 636 lport->tt.disc_stop_final = fc_disc_stop_final; 637 638 if (!lport->tt.disc_recv_req) 639 lport->tt.disc_recv_req = fc_disc_recv_req; 640 641 disc = &lport->disc; 642 INIT_DELAYED_WORK(&disc->disc_work, fc_disc_timeout); 643 mutex_init(&disc->disc_mutex); 644 INIT_LIST_HEAD(&disc->rports); 645 646 disc->lport = lport; 647 648 return 0; 649 } 650 EXPORT_SYMBOL(fc_disc_init); 651