1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25 
  26 /*
  27  * Utility functions used by the dlmgmtd daemon.
  28  */
  29 
  30 #include <assert.h>
  31 #include <pthread.h>
  32 #include <stddef.h>
  33 #include <stdlib.h>
  34 #include <stdio.h>
  35 #include <errno.h>
  36 #include <strings.h>
  37 #include <string.h>
  38 #include <syslog.h>
  39 #include <stdarg.h>
  40 #include <zone.h>
  41 #include <errno.h>
  42 #include <libdlpi.h>
  43 #include "dlmgmt_impl.h"
  44 
  45 /*
  46  * There are three datalink AVL tables.  The dlmgmt_name_avl tree contains all
  47  * datalinks and is keyed by zoneid and link name.  The dlmgmt_id_avl also
  48  * contains all datalinks, and it is keyed by link ID.  The dlmgmt_loan_avl is
  49  * keyed by link name, and contains the set of global-zone links that are
  50  * currently on loan to non-global zones.
  51  */
  52 avl_tree_t      dlmgmt_name_avl;
  53 avl_tree_t      dlmgmt_id_avl;
  54 avl_tree_t      dlmgmt_loan_avl;
  55 
  56 avl_tree_t      dlmgmt_dlconf_avl;
  57 
  58 static pthread_rwlock_t dlmgmt_avl_lock = PTHREAD_RWLOCK_INITIALIZER;
  59 static pthread_mutex_t  dlmgmt_avl_mutex = PTHREAD_MUTEX_INITIALIZER;
  60 static pthread_cond_t   dlmgmt_avl_cv = PTHREAD_COND_INITIALIZER;
  61 static pthread_rwlock_t dlmgmt_dlconf_lock = PTHREAD_RWLOCK_INITIALIZER;
  62 
  63 typedef struct dlmgmt_prefix {
  64         struct dlmgmt_prefix    *lp_next;
  65         char                    lp_prefix[MAXLINKNAMELEN];
  66         zoneid_t                lp_zoneid;
  67         uint_t                  lp_nextppa;
  68 } dlmgmt_prefix_t;
  69 static dlmgmt_prefix_t  dlmgmt_prefixlist;
  70 
  71 datalink_id_t           dlmgmt_nextlinkid;
  72 static datalink_id_t    dlmgmt_nextconfid = 1;
  73 
  74 static void             dlmgmt_advance_linkid(dlmgmt_link_t *);
  75 static void             dlmgmt_advance_ppa(dlmgmt_link_t *);
  76 
  77 void
  78 dlmgmt_log(int pri, const char *fmt, ...)
  79 {
  80         va_list alist;
  81 
  82         va_start(alist, fmt);
  83         if (debug) {
  84                 (void) vfprintf(stderr, fmt, alist);
  85                 (void) fputc('\n', stderr);
  86         } else {
  87                 vsyslog(pri, fmt, alist);
  88         }
  89         va_end(alist);
  90 }
  91 
  92 static int
  93 cmp_link_by_name(const void *v1, const void *v2)
  94 {
  95         const dlmgmt_link_t *link1 = v1;
  96         const dlmgmt_link_t *link2 = v2;
  97         int cmp;
  98 
  99         cmp = strcmp(link1->ll_link, link2->ll_link);
 100         return ((cmp == 0) ? 0 : ((cmp < 0) ? -1 : 1));
 101 }
 102 
 103 /*
 104  * Note that the zoneid associated with a link is effectively part of its
 105  * name.  This is essentially what results in having each zone have disjoint
 106  * datalink namespaces.
 107  */
 108 static int
 109 cmp_link_by_zname(const void *v1, const void *v2)
 110 {
 111         const dlmgmt_link_t *link1 = v1;
 112         const dlmgmt_link_t *link2 = v2;
 113 
 114         if (link1->ll_zoneid < link2->ll_zoneid)
 115                 return (-1);
 116         if (link1->ll_zoneid > link2->ll_zoneid)
 117                 return (1);
 118         return (cmp_link_by_name(link1, link2));
 119 }
 120 
 121 static int
 122 cmp_link_by_id(const void *v1, const void *v2)
 123 {
 124         const dlmgmt_link_t *link1 = v1;
 125         const dlmgmt_link_t *link2 = v2;
 126 
 127         if ((uint64_t)(link1->ll_linkid) == (uint64_t)(link2->ll_linkid))
 128                 return (0);
 129         else if ((uint64_t)(link1->ll_linkid) < (uint64_t)(link2->ll_linkid))
 130                 return (-1);
 131         else
 132                 return (1);
 133 }
 134 
 135 static int
 136 cmp_dlconf_by_id(const void *v1, const void *v2)
 137 {
 138         const dlmgmt_dlconf_t *dlconfp1 = v1;
 139         const dlmgmt_dlconf_t *dlconfp2 = v2;
 140 
 141         if (dlconfp1->ld_id == dlconfp2->ld_id)
 142                 return (0);
 143         else if (dlconfp1->ld_id < dlconfp2->ld_id)
 144                 return (-1);
 145         else
 146                 return (1);
 147 }
 148 
 149 void
 150 dlmgmt_linktable_init(void)
 151 {
 152         /*
 153          * Initialize the prefix list. First add the "net" prefix for the
 154          * global zone to the list.
 155          */
 156         dlmgmt_prefixlist.lp_next = NULL;
 157         dlmgmt_prefixlist.lp_zoneid = GLOBAL_ZONEID;
 158         dlmgmt_prefixlist.lp_nextppa = 0;
 159         (void) strlcpy(dlmgmt_prefixlist.lp_prefix, "net", MAXLINKNAMELEN);
 160 
 161         avl_create(&dlmgmt_name_avl, cmp_link_by_zname, sizeof (dlmgmt_link_t),
 162             offsetof(dlmgmt_link_t, ll_name_node));
 163         avl_create(&dlmgmt_id_avl, cmp_link_by_id, sizeof (dlmgmt_link_t),
 164             offsetof(dlmgmt_link_t, ll_id_node));
 165         avl_create(&dlmgmt_loan_avl, cmp_link_by_name, sizeof (dlmgmt_link_t),
 166             offsetof(dlmgmt_link_t, ll_loan_node));
 167         avl_create(&dlmgmt_dlconf_avl, cmp_dlconf_by_id,
 168             sizeof (dlmgmt_dlconf_t), offsetof(dlmgmt_dlconf_t, ld_node));
 169         dlmgmt_nextlinkid = 1;
 170 }
 171 
 172 void
 173 dlmgmt_linktable_fini(void)
 174 {
 175         dlmgmt_prefix_t *lpp, *next;
 176 
 177         for (lpp = dlmgmt_prefixlist.lp_next; lpp != NULL; lpp = next) {
 178                 next = lpp->lp_next;
 179                 free(lpp);
 180         }
 181 
 182         avl_destroy(&dlmgmt_dlconf_avl);
 183         avl_destroy(&dlmgmt_name_avl);
 184         avl_destroy(&dlmgmt_loan_avl);
 185         avl_destroy(&dlmgmt_id_avl);
 186 }
 187 
 188 static void
 189 linkattr_add(dlmgmt_linkattr_t **headp, dlmgmt_linkattr_t *attrp)
 190 {
 191         if (*headp == NULL) {
 192                 *headp = attrp;
 193         } else {
 194                 (*headp)->lp_prev = attrp;
 195                 attrp->lp_next = *headp;
 196                 *headp = attrp;
 197         }
 198 }
 199 
 200 static void
 201 linkattr_rm(dlmgmt_linkattr_t **headp, dlmgmt_linkattr_t *attrp)
 202 {
 203         dlmgmt_linkattr_t *next, *prev;
 204 
 205         next = attrp->lp_next;
 206         prev = attrp->lp_prev;
 207         if (next != NULL)
 208                 next->lp_prev = prev;
 209         if (prev != NULL)
 210                 prev->lp_next = next;
 211         else
 212                 *headp = next;
 213 }
 214 
 215 dlmgmt_linkattr_t *
 216 linkattr_find(dlmgmt_linkattr_t *headp, const char *attr)
 217 {
 218         dlmgmt_linkattr_t *attrp;
 219 
 220         for (attrp = headp; attrp != NULL; attrp = attrp->lp_next) {
 221                 if (strcmp(attrp->lp_name, attr) == 0)
 222                         break;
 223         }
 224         return (attrp);
 225 }
 226 
 227 int
 228 linkattr_set(dlmgmt_linkattr_t **headp, const char *attr, void *attrval,
 229     size_t attrsz, dladm_datatype_t type)
 230 {
 231         dlmgmt_linkattr_t       *attrp;
 232         void                    *newval;
 233         boolean_t               new;
 234 
 235         attrp = linkattr_find(*headp, attr);
 236         if (attrp != NULL) {
 237                 /*
 238                  * It is already set.  If the value changed, update it.
 239                  */
 240                 if (linkattr_equal(headp, attr, attrval, attrsz))
 241                         return (0);
 242                 new = B_FALSE;
 243         } else {
 244                 /*
 245                  * It is not set yet, allocate the linkattr and prepend to the
 246                  * list.
 247                  */
 248                 if ((attrp = calloc(1, sizeof (dlmgmt_linkattr_t))) == NULL)
 249                         return (ENOMEM);
 250 
 251                 (void) strlcpy(attrp->lp_name, attr, MAXLINKATTRLEN);
 252                 new = B_TRUE;
 253         }
 254         if ((newval = calloc(1, attrsz)) == NULL) {
 255                 if (new)
 256                         free(attrp);
 257                 return (ENOMEM);
 258         }
 259 
 260         if (!new)
 261                 free(attrp->lp_val);
 262         attrp->lp_val = newval;
 263         bcopy(attrval, attrp->lp_val, attrsz);
 264         attrp->lp_sz = attrsz;
 265         attrp->lp_type = type;
 266         attrp->lp_linkprop = dladm_attr_is_linkprop(attr);
 267         if (new)
 268                 linkattr_add(headp, attrp);
 269         return (0);
 270 }
 271 
 272 void
 273 linkattr_unset(dlmgmt_linkattr_t **headp, const char *attr)
 274 {
 275         dlmgmt_linkattr_t *attrp;
 276 
 277         if ((attrp = linkattr_find(*headp, attr)) != NULL) {
 278                 linkattr_rm(headp, attrp);
 279                 free(attrp->lp_val);
 280                 free(attrp);
 281         }
 282 }
 283 
 284 int
 285 linkattr_get(dlmgmt_linkattr_t **headp, const char *attr, void **attrvalp,
 286     size_t *attrszp, dladm_datatype_t *typep)
 287 {
 288         dlmgmt_linkattr_t *attrp;
 289 
 290         if ((attrp = linkattr_find(*headp, attr)) == NULL)
 291                 return (ENOENT);
 292 
 293         *attrvalp = attrp->lp_val;
 294         *attrszp = attrp->lp_sz;
 295         if (typep != NULL)
 296                 *typep = attrp->lp_type;
 297         return (0);
 298 }
 299 
 300 boolean_t
 301 linkattr_equal(dlmgmt_linkattr_t **headp, const char *attr, void *attrval,
 302     size_t attrsz)
 303 {
 304         void    *saved_attrval;
 305         size_t  saved_attrsz;
 306 
 307         if (linkattr_get(headp, attr, &saved_attrval, &saved_attrsz, NULL) != 0)
 308                 return (B_FALSE);
 309 
 310         return ((saved_attrsz == attrsz) &&
 311             (memcmp(saved_attrval, attrval, attrsz) == 0));
 312 }
 313 
 314 void
 315 linkattr_destroy(dlmgmt_link_t *linkp)
 316 {
 317         dlmgmt_linkattr_t *next, *attrp;
 318 
 319         for (attrp = linkp->ll_head; attrp != NULL; attrp = next) {
 320                 next = attrp->lp_next;
 321                 free(attrp->lp_val);
 322                 free(attrp);
 323         }
 324 }
 325 
 326 static int
 327 dlmgmt_table_readwritelock(boolean_t write)
 328 {
 329         if (write)
 330                 return (pthread_rwlock_trywrlock(&dlmgmt_avl_lock));
 331         else
 332                 return (pthread_rwlock_tryrdlock(&dlmgmt_avl_lock));
 333 }
 334 
 335 void
 336 dlmgmt_table_lock(boolean_t write)
 337 {
 338         (void) pthread_mutex_lock(&dlmgmt_avl_mutex);
 339         while (dlmgmt_table_readwritelock(write) == EBUSY)
 340                 (void) pthread_cond_wait(&dlmgmt_avl_cv, &dlmgmt_avl_mutex);
 341 
 342         (void) pthread_mutex_unlock(&dlmgmt_avl_mutex);
 343 }
 344 
 345 void
 346 dlmgmt_table_unlock(void)
 347 {
 348         (void) pthread_rwlock_unlock(&dlmgmt_avl_lock);
 349         (void) pthread_mutex_lock(&dlmgmt_avl_mutex);
 350         (void) pthread_cond_broadcast(&dlmgmt_avl_cv);
 351         (void) pthread_mutex_unlock(&dlmgmt_avl_mutex);
 352 }
 353 
 354 void
 355 link_destroy(dlmgmt_link_t *linkp)
 356 {
 357         linkattr_destroy(linkp);
 358         free(linkp);
 359 }
 360 
 361 /*
 362  * Set the DLMGMT_ACTIVE flag on the link to note that it is active.  When a
 363  * link becomes active and it belongs to a non-global zone, it is also added
 364  * to that zone.
 365  */
 366 int
 367 link_activate(dlmgmt_link_t *linkp)
 368 {
 369         int             err = 0;
 370         zoneid_t        zoneid = ALL_ZONES;
 371 
 372         if (zone_check_datalink(&zoneid, linkp->ll_linkid) == 0) {
 373                 /*
 374                  * This link was already added to a non-global zone.  This can
 375                  * happen if dlmgmtd is restarted.
 376                  */
 377                 if (zoneid != linkp->ll_zoneid) {
 378                         if (link_by_name(linkp->ll_link, zoneid) != NULL) {
 379                                 err = EEXIST;
 380                                 goto done;
 381                         }
 382 
 383                         if (avl_find(&dlmgmt_name_avl, linkp, NULL) != NULL)
 384                                 avl_remove(&dlmgmt_name_avl, linkp);
 385 
 386                         linkp->ll_zoneid = zoneid;
 387                         avl_add(&dlmgmt_name_avl, linkp);
 388                         avl_add(&dlmgmt_loan_avl, linkp);
 389                         linkp->ll_onloan = B_TRUE;
 390                 }
 391         } else if (linkp->ll_zoneid != GLOBAL_ZONEID) {
 392                 err = zone_add_datalink(linkp->ll_zoneid, linkp->ll_linkid);
 393         }
 394 done:
 395         if (err == 0)
 396                 linkp->ll_flags |= DLMGMT_ACTIVE;
 397         return (err);
 398 }
 399 
 400 /*
 401  * Is linkp visible from the caller's zoneid?  It is if the link is in the
 402  * same zone as the caller, or if the caller is in the global zone and the
 403  * link is on loan to a non-global zone.
 404  */
 405 boolean_t
 406 link_is_visible(dlmgmt_link_t *linkp, zoneid_t zoneid)
 407 {
 408         return (linkp->ll_zoneid == zoneid ||
 409             (zoneid == GLOBAL_ZONEID && linkp->ll_onloan));
 410 }
 411 
 412 dlmgmt_link_t *
 413 link_by_id(datalink_id_t linkid, zoneid_t zoneid)
 414 {
 415         dlmgmt_link_t link, *linkp;
 416 
 417         link.ll_linkid = linkid;
 418         if ((linkp = avl_find(&dlmgmt_id_avl, &link, NULL)) == NULL)
 419                 return (NULL);
 420         if (zoneid != GLOBAL_ZONEID && linkp->ll_zoneid != zoneid)
 421                 return (NULL);
 422         return (linkp);
 423 }
 424 
 425 dlmgmt_link_t *
 426 link_by_name(const char *name, zoneid_t zoneid)
 427 {
 428         dlmgmt_link_t   link, *linkp;
 429 
 430         (void) strlcpy(link.ll_link, name, MAXLINKNAMELEN);
 431         link.ll_zoneid = zoneid;
 432         linkp = avl_find(&dlmgmt_name_avl, &link, NULL);
 433         if (linkp == NULL && zoneid == GLOBAL_ZONEID) {
 434                 /* The link could be on loan to a non-global zone? */
 435                 linkp = avl_find(&dlmgmt_loan_avl, &link, NULL);
 436         }
 437         return (linkp);
 438 }
 439 
 440 int
 441 dlmgmt_create_common(const char *name, datalink_class_t class, uint32_t media,
 442     zoneid_t zoneid, uint32_t flags, dlmgmt_link_t **linkpp)
 443 {
 444         dlmgmt_link_t   *linkp = NULL;
 445         avl_index_t     name_where, id_where;
 446         int             err = 0;
 447 
 448         if (!dladm_valid_linkname(name))
 449                 return (EINVAL);
 450         if (dlmgmt_nextlinkid == DATALINK_INVALID_LINKID)
 451                 return (ENOSPC);
 452 
 453         if ((linkp = calloc(1, sizeof (dlmgmt_link_t))) == NULL) {
 454                 err = ENOMEM;
 455                 goto done;
 456         }
 457 
 458         (void) strlcpy(linkp->ll_link, name, MAXLINKNAMELEN);
 459         linkp->ll_class = class;
 460         linkp->ll_media = media;
 461         linkp->ll_linkid = dlmgmt_nextlinkid;
 462         linkp->ll_zoneid = zoneid;
 463         linkp->ll_gen = 0;
 464 
 465         if (avl_find(&dlmgmt_name_avl, linkp, &name_where) != NULL ||
 466             avl_find(&dlmgmt_id_avl, linkp, &id_where) != NULL) {
 467                 err = EEXIST;
 468                 goto done;
 469         }
 470 
 471         avl_insert(&dlmgmt_name_avl, linkp, name_where);
 472         avl_insert(&dlmgmt_id_avl, linkp, id_where);
 473 
 474         if ((flags & DLMGMT_ACTIVE) && (err = link_activate(linkp)) != 0) {
 475                 avl_remove(&dlmgmt_name_avl, linkp);
 476                 avl_remove(&dlmgmt_id_avl, linkp);
 477                 goto done;
 478         }
 479 
 480         linkp->ll_flags = flags;
 481         dlmgmt_advance(linkp);
 482         *linkpp = linkp;
 483 
 484 done:
 485         if (err != 0)
 486                 free(linkp);
 487         return (err);
 488 }
 489 
 490 int
 491 dlmgmt_destroy_common(dlmgmt_link_t *linkp, uint32_t flags)
 492 {
 493         if ((linkp->ll_flags & flags) == 0) {
 494                 /*
 495                  * The link does not exist in the specified space.
 496                  */
 497                 return (ENOENT);
 498         }
 499 
 500         linkp->ll_flags &= ~flags;
 501         if (flags & DLMGMT_PERSIST) {
 502                 dlmgmt_linkattr_t *next, *attrp;
 503 
 504                 for (attrp = linkp->ll_head; attrp != NULL; attrp = next) {
 505                         next = attrp->lp_next;
 506                         free(attrp->lp_val);
 507                         free(attrp);
 508                 }
 509                 linkp->ll_head = NULL;
 510         }
 511 
 512         if ((flags & DLMGMT_ACTIVE) && linkp->ll_zoneid != GLOBAL_ZONEID) {
 513                 (void) zone_remove_datalink(linkp->ll_zoneid, linkp->ll_linkid);
 514                 if (linkp->ll_onloan)
 515                         avl_remove(&dlmgmt_loan_avl, linkp);
 516         }
 517 
 518         if (linkp->ll_flags == 0) {
 519                 avl_remove(&dlmgmt_id_avl, linkp);
 520                 avl_remove(&dlmgmt_name_avl, linkp);
 521                 link_destroy(linkp);
 522         }
 523 
 524         return (0);
 525 }
 526 
 527 int
 528 dlmgmt_getattr_common(dlmgmt_linkattr_t **headp, const char *attr,
 529     dlmgmt_getattr_retval_t *retvalp)
 530 {
 531         int                     err;
 532         void                    *attrval;
 533         size_t                  attrsz;
 534         dladm_datatype_t        attrtype;
 535 
 536         err = linkattr_get(headp, attr, &attrval, &attrsz, &attrtype);
 537         if (err != 0)
 538                 return (err);
 539 
 540         assert(attrsz > 0);
 541         if (attrsz > MAXLINKATTRVALLEN)
 542                 return (EINVAL);
 543 
 544         retvalp->lr_type = attrtype;
 545         retvalp->lr_attrsz = attrsz;
 546         bcopy(attrval, retvalp->lr_attrval, attrsz);
 547         return (0);
 548 }
 549 
 550 void
 551 dlmgmt_dlconf_table_lock(boolean_t write)
 552 {
 553         if (write)
 554                 (void) pthread_rwlock_wrlock(&dlmgmt_dlconf_lock);
 555         else
 556                 (void) pthread_rwlock_rdlock(&dlmgmt_dlconf_lock);
 557 }
 558 
 559 void
 560 dlmgmt_dlconf_table_unlock(void)
 561 {
 562         (void) pthread_rwlock_unlock(&dlmgmt_dlconf_lock);
 563 }
 564 
 565 int
 566 dlconf_create(const char *name, datalink_id_t linkid, datalink_class_t class,
 567     uint32_t media, zoneid_t zoneid, dlmgmt_dlconf_t **dlconfpp)
 568 {
 569         dlmgmt_dlconf_t *dlconfp = NULL;
 570         int             err = 0;
 571 
 572         if (dlmgmt_nextconfid == 0) {
 573                 err = ENOSPC;
 574                 goto done;
 575         }
 576 
 577         if ((dlconfp = calloc(1, sizeof (dlmgmt_dlconf_t))) == NULL) {
 578                 err = ENOMEM;
 579                 goto done;
 580         }
 581 
 582         (void) strlcpy(dlconfp->ld_link, name, MAXLINKNAMELEN);
 583         dlconfp->ld_linkid = linkid;
 584         dlconfp->ld_class = class;
 585         dlconfp->ld_media = media;
 586         dlconfp->ld_id = dlmgmt_nextconfid;
 587         dlconfp->ld_zoneid = zoneid;
 588 
 589 done:
 590         *dlconfpp = dlconfp;
 591         return (err);
 592 }
 593 
 594 void
 595 dlconf_destroy(dlmgmt_dlconf_t *dlconfp)
 596 {
 597         dlmgmt_linkattr_t *next, *attrp;
 598 
 599         for (attrp = dlconfp->ld_head; attrp != NULL; attrp = next) {
 600                 next = attrp->lp_next;
 601                 free(attrp->lp_val);
 602                 free(attrp);
 603         }
 604         free(dlconfp);
 605 }
 606 
 607 int
 608 dlmgmt_generate_name(const char *prefix, char *name, size_t size,
 609     zoneid_t zoneid)
 610 {
 611         dlmgmt_prefix_t *lpp, *prev = NULL;
 612         dlmgmt_link_t   link, *linkp;
 613 
 614         /*
 615          * See whether the requested prefix is already in the list.
 616          */
 617         for (lpp = &dlmgmt_prefixlist; lpp != NULL;
 618             prev = lpp, lpp = lpp->lp_next) {
 619                 if (lpp->lp_zoneid == zoneid &&
 620                     strcmp(prefix, lpp->lp_prefix) == 0)
 621                         break;
 622         }
 623 
 624         /*
 625          * Not found.
 626          */
 627         if (lpp == NULL) {
 628                 assert(prev != NULL);
 629 
 630                 /*
 631                  * First add this new prefix into the prefix list.
 632                  */
 633                 if ((lpp = malloc(sizeof (dlmgmt_prefix_t))) == NULL)
 634                         return (ENOMEM);
 635 
 636                 prev->lp_next = lpp;
 637                 lpp->lp_next = NULL;
 638                 lpp->lp_zoneid = zoneid;
 639                 lpp->lp_nextppa = 0;
 640                 (void) strlcpy(lpp->lp_prefix, prefix, MAXLINKNAMELEN);
 641 
 642                 /*
 643                  * Now determine this prefix's nextppa.
 644                  */
 645                 (void) snprintf(link.ll_link, MAXLINKNAMELEN, "%s%d",
 646                     prefix, 0);
 647                 link.ll_zoneid = zoneid;
 648                 if ((linkp = avl_find(&dlmgmt_name_avl, &link, NULL)) != NULL)
 649                         dlmgmt_advance_ppa(linkp);
 650         }
 651 
 652         if (lpp->lp_nextppa == (uint_t)-1)
 653                 return (ENOSPC);
 654 
 655         (void) snprintf(name, size, "%s%d", prefix, lpp->lp_nextppa);
 656         return (0);
 657 }
 658 
 659 /*
 660  * Advance the next available ppa value if the name prefix of the current
 661  * link is in the prefix list.
 662  */
 663 static void
 664 dlmgmt_advance_ppa(dlmgmt_link_t *linkp)
 665 {
 666         dlmgmt_prefix_t *lpp;
 667         char            prefix[MAXLINKNAMELEN];
 668         char            linkname[MAXLINKNAMELEN];
 669         uint_t          start, ppa;
 670 
 671         (void) dlpi_parselink(linkp->ll_link, prefix, &ppa);
 672 
 673         /*
 674          * See whether the requested prefix is already in the list.
 675          */
 676         for (lpp = &dlmgmt_prefixlist; lpp != NULL; lpp = lpp->lp_next) {
 677                 if (lpp->lp_zoneid == linkp->ll_zoneid &&
 678                     strcmp(prefix, lpp->lp_prefix) == 0)
 679                         break;
 680         }
 681 
 682         /*
 683          * If the link name prefix is in the list, advance the
 684          * next available ppa for the <prefix>N name.
 685          */
 686         if (lpp == NULL || lpp->lp_nextppa != ppa)
 687                 return;
 688 
 689         start = lpp->lp_nextppa++;
 690         linkp = AVL_NEXT(&dlmgmt_name_avl, linkp);
 691         while (lpp->lp_nextppa != start) {
 692                 if (lpp->lp_nextppa == (uint_t)-1) {
 693                         /*
 694                          * wrapped around. search from <prefix>1.
 695                          */
 696                         lpp->lp_nextppa = 0;
 697                         (void) snprintf(linkname, MAXLINKNAMELEN,
 698                             "%s%d", lpp->lp_prefix, lpp->lp_nextppa);
 699                         linkp = link_by_name(linkname, lpp->lp_zoneid);
 700                         if (linkp == NULL)
 701                                 return;
 702                 } else {
 703                         if (linkp == NULL)
 704                                 return;
 705                         (void) dlpi_parselink(linkp->ll_link, prefix, &ppa);
 706                         if ((strcmp(prefix, lpp->lp_prefix) != 0) ||
 707                             (ppa != lpp->lp_nextppa)) {
 708                                 return;
 709                         }
 710                 }
 711                 linkp = AVL_NEXT(&dlmgmt_name_avl, linkp);
 712                 lpp->lp_nextppa++;
 713         }
 714         lpp->lp_nextppa = (uint_t)-1;
 715 }
 716 
 717 /*
 718  * Advance to the next available linkid value.
 719  */
 720 static void
 721 dlmgmt_advance_linkid(dlmgmt_link_t *linkp)
 722 {
 723         datalink_id_t   start;
 724 
 725         if (linkp->ll_linkid != dlmgmt_nextlinkid)
 726                 return;
 727 
 728         start = dlmgmt_nextlinkid;
 729         linkp = AVL_NEXT(&dlmgmt_id_avl, linkp);
 730 
 731         do {
 732                 if (dlmgmt_nextlinkid == DATALINK_MAX_LINKID) {
 733                         /*
 734                          * wrapped around. search from 1.
 735                          */
 736                         dlmgmt_nextlinkid = 1;
 737                         if ((linkp = link_by_id(1, GLOBAL_ZONEID)) == NULL)
 738                                 return;
 739                 } else {
 740                         dlmgmt_nextlinkid++;
 741                         if (linkp == NULL)
 742                                 return;
 743                         if (linkp->ll_linkid != dlmgmt_nextlinkid)
 744                                 return;
 745                 }
 746 
 747                 linkp = AVL_NEXT(&dlmgmt_id_avl, linkp);
 748         } while (dlmgmt_nextlinkid != start);
 749 
 750         dlmgmt_nextlinkid = DATALINK_INVALID_LINKID;
 751 }
 752 
 753 /*
 754  * Advance various global values, for example, next linkid value, next ppa for
 755  * various prefix etc.
 756  */
 757 void
 758 dlmgmt_advance(dlmgmt_link_t *linkp)
 759 {
 760         dlmgmt_advance_linkid(linkp);
 761         dlmgmt_advance_ppa(linkp);
 762 }
 763 
 764 /*
 765  * Advance to the next available dlconf id.
 766  */
 767 void
 768 dlmgmt_advance_dlconfid(dlmgmt_dlconf_t *dlconfp)
 769 {
 770         uint_t  start;
 771 
 772         start = dlmgmt_nextconfid++;
 773         dlconfp = AVL_NEXT(&dlmgmt_dlconf_avl, dlconfp);
 774         while (dlmgmt_nextconfid != start) {
 775                 if (dlmgmt_nextconfid == 0) {
 776                         dlmgmt_dlconf_t dlconf;
 777 
 778                         /*
 779                          * wrapped around. search from 1.
 780                          */
 781                         dlconf.ld_id = dlmgmt_nextconfid = 1;
 782                         dlconfp = avl_find(&dlmgmt_dlconf_avl, &dlconf, NULL);
 783                         if (dlconfp == NULL)
 784                                 return;
 785                 } else {
 786                         if ((dlconfp == NULL) ||
 787                             (dlconfp->ld_id != dlmgmt_nextconfid)) {
 788                                 return;
 789                         }
 790                 }
 791                 dlconfp = AVL_NEXT(&dlmgmt_dlconf_avl, dlconfp);
 792                 dlmgmt_nextconfid++;
 793         }
 794         dlmgmt_nextconfid = 0;
 795 }