source/heimdal/lib/krb5/krbhst.c

   1 /*
   2  * Copyright (c) 2001 - 2003 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "krb5_locl.h"
  35 #include <resolve.h>
  36 #include "locate_plugin.h"
  37
  38 RCSID("$Id: krbhst.c,v 1.58 2006/11/12 20:05:20 lha Exp $");
  39
  40 static int
  41 string_to_proto(const char *string)
  42 {
  43     if(strcasecmp(string, "udp") == 0)
  44         return KRB5_KRBHST_UDP;
  45     else if(strcasecmp(string, "tcp") == 0)
  46         return KRB5_KRBHST_TCP;
  47     else if(strcasecmp(string, "http") == 0)
  48         return KRB5_KRBHST_HTTP;
  49     return -1;
  50 }
  51
  52 /*
  53  * set `res' and `count' to the result of looking up SRV RR in DNS for
  54  * `proto', `proto', `realm' using `dns_type'.
  55  * if `port' != 0, force that port number
  56  */
  57
  58 static krb5_error_code
  59 srv_find_realm(krb5_context context, krb5_krbhst_info ***res, int *count,
  60                const char *realm, const char *dns_type,
  61                const char *proto, const char *service, int port)
  62 {
  63     char domain[1024];
  64     struct dns_reply *r;
  65     struct resource_record *rr;
  66     int num_srv;
  67     int proto_num;
  68     int def_port;
  69
  70     *res = NULL;
  71     *count = 0;
  72
  73     proto_num = string_to_proto(proto);
  74     if(proto_num < 0) {
  75         krb5_set_error_string(context, "unknown protocol `%s'", proto);
  76         return EINVAL;
  77     }
  78
  79     if(proto_num == KRB5_KRBHST_HTTP)
  80         def_port = ntohs(krb5_getportbyname (context, "http", "tcp", 80));
  81     else if(port == 0)
  82         def_port = ntohs(krb5_getportbyname (context, service, proto, 88));
  83     else
  84         def_port = port;
  85
  86     snprintf(domain, sizeof(domain), "_%s._%s.%s.", service, proto, realm);
  87
  88     r = dns_lookup(domain, dns_type);
  89     if(r == NULL)
  90         return KRB5_KDC_UNREACH;
  91
  92     for(num_srv = 0, rr = r->head; rr; rr = rr->next)
  93         if(rr->type == T_SRV)
  94             num_srv++;
  95
  96     *res = malloc(num_srv * sizeof(**res));
  97     if(*res == NULL) {
  98         dns_free_data(r);
  99         krb5_set_error_string(context, "malloc: out of memory");
 100         return ENOMEM;
 101     }
 102
 103     dns_srv_order(r);
 104
 105     for(num_srv = 0, rr = r->head; rr; rr = rr->next)
 106         if(rr->type == T_SRV) {
 107             krb5_krbhst_info *hi;
 108             size_t len = strlen(rr->u.srv->target);
 109
 110             hi = calloc(1, sizeof(*hi) + len);
 111             if(hi == NULL) {
 112                 dns_free_data(r);
 113                 while(--num_srv >= 0)
 114                     free((*res)[num_srv]);
 115                 free(*res);
 116                 *res = NULL;
 117                 return ENOMEM;
 118             }
 119             (*res)[num_srv++] = hi;
 120
 121             hi->proto = proto_num;
 122
 123             hi->def_port = def_port;
 124             if (port != 0)
 125                 hi->port = port;
 126             else
 127                 hi->port = rr->u.srv->port;
 128
 129             strlcpy(hi->hostname, rr->u.srv->target, len + 1);
 130         }
 131
 132     *count = num_srv;
 133
 134     dns_free_data(r);
 135     return 0;
 136 }
 137
 138
 139 struct krb5_krbhst_data {
 140     char *realm;
 141     unsigned int flags;
 142     int def_port;
 143     int port;                   /* hardwired port number if != 0 */
 144 #define KD_CONFIG                1
 145 #define KD_SRV_UDP               2
 146 #define KD_SRV_TCP               4
 147 #define KD_SRV_HTTP              8
 148 #define KD_FALLBACK             16
 149 #define KD_CONFIG_EXISTS        32
 150 #define KD_LARGE_MSG            64
 151 #define KD_PLUGIN              128
 152     krb5_error_code (*get_next)(krb5_context, struct krb5_krbhst_data *,
 153                                 krb5_krbhst_info**);
 154
 155     unsigned int fallback_count;
 156
 157     struct krb5_krbhst_info *hosts, **index, **end;
 158 };
 159
 160 static krb5_boolean
 161 krbhst_empty(const struct krb5_krbhst_data *kd)
 162 {
 163     return kd->index == &kd->hosts;
 164 }
 165
 166 /*
 167  * Return the default protocol for the `kd' (either TCP or UDP)
 168  */
 169
 170 static int
 171 krbhst_get_default_proto(struct krb5_krbhst_data *kd)
 172 {
 173     if (kd->flags & KD_LARGE_MSG)
 174         return KRB5_KRBHST_TCP;
 175     return KRB5_KRBHST_UDP;
 176 }
 177
 178
 179 /*
 180  * parse `spec' into a krb5_krbhst_info, defaulting the port to `def_port'
 181  * and forcing it to `port' if port != 0
 182  */
 183
 184 static struct krb5_krbhst_info*
 185 parse_hostspec(krb5_context context, struct krb5_krbhst_data *kd,
 186                const char *spec, int def_port, int port)
 187 {
 188     const char *p = spec;
 189     struct krb5_krbhst_info *hi;
 190
 191     hi = calloc(1, sizeof(*hi) + strlen(spec));
 192     if(hi == NULL)
 193         return NULL;
 194
 195     hi->proto = krbhst_get_default_proto(kd);
 196
 197     if(strncmp(p, "http://", 7) == 0){
 198         hi->proto = KRB5_KRBHST_HTTP;
 199         p += 7;
 200     } else if(strncmp(p, "http/", 5) == 0) {
 201         hi->proto = KRB5_KRBHST_HTTP;
 202         p += 5;
 203         def_port = ntohs(krb5_getportbyname (context, "http", "tcp", 80));
 204     }else if(strncmp(p, "tcp/", 4) == 0){
 205         hi->proto = KRB5_KRBHST_TCP;
 206         p += 4;
 207     } else if(strncmp(p, "udp/", 4) == 0) {
 208         p += 4;
 209     }
 210
 211     if(strsep_copy(&p, ":", hi->hostname, strlen(spec) + 1) < 0) {
 212         free(hi);
 213         return NULL;
 214     }
 215     /* get rid of trailing /, and convert to lower case */
 216     hi->hostname[strcspn(hi->hostname, "/")] = '\0';
 217     strlwr(hi->hostname);
 218
 219     hi->port = hi->def_port = def_port;
 220     if(p != NULL) {
 221         char *end;
 222         hi->port = strtol(p, &end, 0);
 223         if(end == p) {
 224             free(hi);
 225             return NULL;
 226         }
 227     }
 228     if (port)
 229         hi->port = port;
 230     return hi;
 231 }
 232
 233 void
 234 _krb5_free_krbhst_info(krb5_krbhst_info *hi)
 235 {
 236     if (hi->ai != NULL)
 237         freeaddrinfo(hi->ai);
 238     free(hi);
 239 }
 240
 241 krb5_error_code
 242 _krb5_krbhost_info_move(krb5_context context,
 243                         krb5_krbhst_info *from,
 244                         krb5_krbhst_info **to)
 245 {
 246     size_t hostnamelen = strlen(from->hostname);
 247     /* trailing NUL is included in structure */
 248     *to = calloc(1, sizeof(**to) + hostnamelen);
 249     if(*to == NULL) {
 250         krb5_set_error_string(context, "malloc - out of memory");
 251         return ENOMEM;
 252     }
 253
 254     (*to)->proto = from->proto;
 255     (*to)->port = from->port;
 256     (*to)->def_port = from->def_port;
 257     (*to)->ai = from->ai;
 258     from->ai = NULL;
 259     (*to)->next = NULL;
 260     memcpy((*to)->hostname, from->hostname, hostnamelen + 1);
 261     return 0;
 262 }
 263
 264
 265 static void
 266 append_host_hostinfo(struct krb5_krbhst_data *kd, struct krb5_krbhst_info *host)
 267 {
 268     struct krb5_krbhst_info *h;
 269
 270     for(h = kd->hosts; h; h = h->next)
 271         if(h->proto == host->proto &&
 272            h->port == host->port &&
 273            strcmp(h->hostname, host->hostname) == 0) {
 274             _krb5_free_krbhst_info(host);
 275             return;
 276         }
 277     *kd->end = host;
 278     kd->end = &host->next;
 279 }
 280
 281 static krb5_error_code
 282 append_host_string(krb5_context context, struct krb5_krbhst_data *kd,
 283                    const char *host, int def_port, int port)
 284 {
 285     struct krb5_krbhst_info *hi;
 286
 287     hi = parse_hostspec(context, kd, host, def_port, port);
 288     if(hi == NULL)
 289         return ENOMEM;
 290
 291     append_host_hostinfo(kd, hi);
 292     return 0;
 293 }
 294
 295 /*
 296  * return a readable representation of `host' in `hostname, hostlen'
 297  */
 298
 299 krb5_error_code KRB5_LIB_FUNCTION
 300 krb5_krbhst_format_string(krb5_context context, const krb5_krbhst_info *host,
 301                           char *hostname, size_t hostlen)
 302 {
 303     const char *proto = "";
 304     char portstr[7] = "";
 305     if(host->proto == KRB5_KRBHST_TCP)
 306         proto = "tcp/";
 307     else if(host->proto == KRB5_KRBHST_HTTP)
 308         proto = "http://";
 309     if(host->port != host->def_port)
 310         snprintf(portstr, sizeof(portstr), ":%d", host->port);
 311     snprintf(hostname, hostlen, "%s%s%s", proto, host->hostname, portstr);
 312     return 0;
 313 }
 314
 315 /*
 316  * create a getaddrinfo `hints' based on `proto'
 317  */
 318
 319 static void
 320 make_hints(struct addrinfo *hints, int proto)
 321 {
 322     memset(hints, 0, sizeof(*hints));
 323     hints->ai_family = AF_UNSPEC;
 324     switch(proto) {
 325     case KRB5_KRBHST_UDP :
 326         hints->ai_socktype = SOCK_DGRAM;
 327         break;
 328     case KRB5_KRBHST_HTTP :
 329     case KRB5_KRBHST_TCP :
 330         hints->ai_socktype = SOCK_STREAM;
 331         break;
 332     }
 333 }
 334
 335 /*
 336  * return an `struct addrinfo *' in `ai' corresponding to the information
 337  * in `host'.  free:ing is handled by krb5_krbhst_free.
 338  */
 339
 340 krb5_error_code KRB5_LIB_FUNCTION
 341 krb5_krbhst_get_addrinfo(krb5_context context, krb5_krbhst_info *host,
 342                          struct addrinfo **ai)
 343 {
 344     struct addrinfo hints;
 345     char portstr[NI_MAXSERV];
 346     int ret;
 347
 348     if (host->ai == NULL) {
 349         make_hints(&hints, host->proto);
 350         snprintf (portstr, sizeof(portstr), "%d", host->port);
 351         ret = getaddrinfo(host->hostname, portstr, &hints, &host->ai);
 352         if (ret)
 353             return krb5_eai_to_heim_errno(ret, errno);
 354     }
 355     *ai = host->ai;
 356     return 0;
 357 }
 358
 359 static krb5_boolean
 360 get_next(struct krb5_krbhst_data *kd, krb5_krbhst_info **host)
 361 {
 362     struct krb5_krbhst_info *hi = *kd->index;
 363     if(hi != NULL) {
 364         *host = hi;
 365         kd->index = &(*kd->index)->next;
 366         return TRUE;
 367     }
 368     return FALSE;
 369 }
 370
 371 static void
 372 srv_get_hosts(krb5_context context, struct krb5_krbhst_data *kd,
 373               const char *proto, const char *service)
 374 {
 375     krb5_krbhst_info **res;
 376     int count, i;
 377
 378     if (srv_find_realm(context, &res, &count, kd->realm, "SRV", proto, service,
 379                        kd->port))
 380         return;
 381     for(i = 0; i < count; i++)
 382         append_host_hostinfo(kd, res[i]);
 383     free(res);
 384 }
 385
 386 /*
 387  * read the configuration for `conf_string', defaulting to kd->def_port and
 388  * forcing it to `kd->port' if kd->port != 0
 389  */
 390
 391 static void
 392 config_get_hosts(krb5_context context, struct krb5_krbhst_data *kd,
 393                  const char *conf_string)
 394 {
 395     int i;
 396
 397     char **hostlist;
 398     hostlist = krb5_config_get_strings(context, NULL,
 399                                        "realms", kd->realm, conf_string, NULL);
 400
 401     if(hostlist == NULL)
 402         return;
 403     kd->flags |= KD_CONFIG_EXISTS;
 404     for(i = 0; hostlist && hostlist[i] != NULL; i++)
 405         append_host_string(context, kd, hostlist[i], kd->def_port, kd->port);
 406
 407     krb5_config_free_strings(hostlist);
 408 }
 409
 410 /*
 411  * as a fallback, look for `serv_string.kd->realm' (typically
 412  * kerberos.REALM, kerberos-1.REALM, ...
 413  * `port' is the default port for the service, and `proto' the
 414  * protocol
 415  */
 416
 417 static krb5_error_code
 418 fallback_get_hosts(krb5_context context, struct krb5_krbhst_data *kd,
 419                    const char *serv_string, int port, int proto)
 420 {
 421     char *host;
 422     int ret;
 423     struct addrinfo *ai;
 424     struct addrinfo hints;
 425     char portstr[NI_MAXSERV];
 426
 427     /*
 428      * Don't try forever in case the DNS server keep returning us
 429      * entries (like wildcard entries or the .nu TLD)
 430      */
 431     if(kd->fallback_count >= 5) {
 432         kd->flags |= KD_FALLBACK;
 433         return 0;
 434     }
 435
 436     if(kd->fallback_count == 0)
 437         asprintf(&host, "%s.%s.", serv_string, kd->realm);
 438     else
 439         asprintf(&host, "%s-%d.%s.",
 440                  serv_string, kd->fallback_count, kd->realm);
 441
 442     if (host == NULL)
 443         return ENOMEM;
 444
 445     make_hints(&hints, proto);
 446     snprintf(portstr, sizeof(portstr), "%d", port);
 447     ret = getaddrinfo(host, portstr, &hints, &ai);
 448     if (ret) {
 449         /* no more hosts, so we're done here */
 450         free(host);
 451         kd->flags |= KD_FALLBACK;
 452     } else {
 453         struct krb5_krbhst_info *hi;
 454         size_t hostlen = strlen(host);
 455
 456         hi = calloc(1, sizeof(*hi) + hostlen);
 457         if(hi == NULL) {
 458             free(host);
 459             return ENOMEM;
 460         }
 461
 462         hi->proto = proto;
 463         hi->port  = hi->def_port = port;
 464         hi->ai    = ai;
 465         memmove(hi->hostname, host, hostlen);
 466         hi->hostname[hostlen] = '\0';
 467         free(host);
 468         append_host_hostinfo(kd, hi);
 469         kd->fallback_count++;
 470     }
 471     return 0;
 472 }
 473
 474 /*
 475  * Fetch hosts from plugin
 476  */
 477
 478 static krb5_error_code
 479 add_locate(void *ctx, int type, struct sockaddr *addr)
 480 {
 481     struct krb5_krbhst_info *hi;
 482     struct krb5_krbhst_data *kd = ctx;
 483     char host[NI_MAXHOST], port[NI_MAXSERV];
 484     struct addrinfo hints, *ai;
 485     socklen_t socklen;
 486     size_t hostlen;
 487     int ret;
 488
 489     socklen = socket_sockaddr_size(addr);
 490
 491     ret = getnameinfo(addr, socklen, host, sizeof(host), port, sizeof(port),
 492                       NI_NUMERICHOST|NI_NUMERICSERV);
 493     if (ret != 0)
 494         return 0;
 495
 496     memset(&hints, 0, sizeof(hints));
 497     ret = getaddrinfo(host, port, &hints, &ai);
 498     if (ret)
 499         return 0;
 500
 501     hostlen = strlen(host);
 502
 503     hi = calloc(1, sizeof(*hi) + hostlen);
 504     if(hi == NULL) {
 505         free(host);
 506         return ENOMEM;
 507     }
 508
 509     hi->proto = krbhst_get_default_proto(kd);
 510     hi->port  = hi->def_port = socket_get_port(addr);
 511     hi->ai    = ai;
 512     memmove(hi->hostname, host, hostlen);
 513     hi->hostname[hostlen] = '\0';
 514     append_host_hostinfo(kd, hi);
 515
 516     return 0;
 517 }
 518
 519 static void
 520 plugin_get_hosts(krb5_context context,
 521                  struct krb5_krbhst_data *kd,
 522                  enum locate_service_type type)
 523 {
 524     struct krb5_plugin *list, *e;
 525     krb5_error_code ret;
 526
 527     ret = _krb5_plugin_find(context, PLUGIN_TYPE_DATA, "resolve", &list);
 528     if(ret != 0 || list == NULL)
 529         return;
 530
 531     kd->flags |= KD_CONFIG_EXISTS;
 532
 533     for (e = list; e != NULL; e = _krb5_plugin_get_next(e)) {
 534         krb5plugin_service_locate_ftable *service;
 535         void *ctx;
 536
 537         service = _krb5_plugin_get_symbol(e);
 538         if (service->minor_version != 0)
 539             continue;
 540
 541         (*service->init)(context, &ctx);
 542         ret = (*service->lookup)(ctx, type, kd->realm, 0, 0, add_locate, kd);
 543         (*service->fini)(ctx);
 544         if (ret) {
 545             krb5_set_error_string(context, "Plugin failed to lookup");
 546             break;
 547         }
 548     }
 549     _krb5_plugin_free(list);
 550 }
 551
 552 /*
 553  *
 554  */
 555
 556 static krb5_error_code
 557 kdc_get_next(krb5_context context,
 558              struct krb5_krbhst_data *kd,
 559              krb5_krbhst_info **host)
 560 {
 561     krb5_error_code ret;
 562
 563     if ((kd->flags & KD_PLUGIN) == 0) {
 564         plugin_get_hosts(context, kd, locate_service_kdc);
 565         kd->flags |= KD_PLUGIN;
 566         if(get_next(kd, host))
 567             return 0;
 568     }
 569
 570     if((kd->flags & KD_CONFIG) == 0) {
 571         config_get_hosts(context, kd, "kdc");
 572         kd->flags |= KD_CONFIG;
 573         if(get_next(kd, host))
 574             return 0;
 575     }
 576
 577     if (kd->flags & KD_CONFIG_EXISTS)
 578         return KRB5_KDC_UNREACH; /* XXX */
 579
 580     if(context->srv_lookup) {
 581         if((kd->flags & KD_SRV_UDP) == 0 && (kd->flags & KD_LARGE_MSG) == 0) {
 582             srv_get_hosts(context, kd, "udp", "kerberos");
 583             kd->flags |= KD_SRV_UDP;
 584             if(get_next(kd, host))
 585                 return 0;
 586         }
 587
 588         if((kd->flags & KD_SRV_TCP) == 0) {
 589             srv_get_hosts(context, kd, "tcp", "kerberos");
 590             kd->flags |= KD_SRV_TCP;
 591             if(get_next(kd, host))
 592                 return 0;
 593         }
 594         if((kd->flags & KD_SRV_HTTP) == 0) {
 595             srv_get_hosts(context, kd, "http", "kerberos");
 596             kd->flags |= KD_SRV_HTTP;
 597             if(get_next(kd, host))
 598                 return 0;
 599         }
 600     }
 601
 602     while((kd->flags & KD_FALLBACK) == 0) {
 603         ret = fallback_get_hosts(context, kd, "kerberos",
 604                                  kd->def_port,
 605                                  krbhst_get_default_proto(kd));
 606         if(ret)
 607             return ret;
 608         if(get_next(kd, host))
 609             return 0;
 610     }
 611
 612     return KRB5_KDC_UNREACH; /* XXX */
 613 }
 614
 615 static krb5_error_code
 616 admin_get_next(krb5_context context,
 617                struct krb5_krbhst_data *kd,
 618                krb5_krbhst_info **host)
 619 {
 620     krb5_error_code ret;
 621
 622     if((kd->flags & KD_CONFIG) == 0) {
 623         config_get_hosts(context, kd, "admin_server");
 624         kd->flags |= KD_CONFIG;
 625         if(get_next(kd, host))
 626             return 0;
 627     }
 628
 629     if (kd->flags & KD_CONFIG_EXISTS)
 630         return KRB5_KDC_UNREACH; /* XXX */
 631
 632     if(context->srv_lookup) {
 633         if((kd->flags & KD_SRV_TCP) == 0) {
 634             srv_get_hosts(context, kd, "tcp", "kerberos-adm");
 635             kd->flags |= KD_SRV_TCP;
 636             if(get_next(kd, host))
 637                 return 0;
 638         }
 639     }
 640
 641     if (krbhst_empty(kd)
 642         && (kd->flags & KD_FALLBACK) == 0) {
 643         ret = fallback_get_hosts(context, kd, "kerberos",
 644                                  kd->def_port,
 645                                  krbhst_get_default_proto(kd));
 646         if(ret)
 647             return ret;
 648         kd->flags |= KD_FALLBACK;
 649         if(get_next(kd, host))
 650             return 0;
 651     }
 652
 653     return KRB5_KDC_UNREACH;    /* XXX */
 654 }
 655
 656 static krb5_error_code
 657 kpasswd_get_next(krb5_context context,
 658                  struct krb5_krbhst_data *kd,
 659                  krb5_krbhst_info **host)
 660 {
 661     krb5_error_code ret;
 662
 663     if((kd->flags & KD_CONFIG) == 0) {
 664         config_get_hosts(context, kd, "kpasswd_server");
 665         kd->flags |= KD_CONFIG;
 666         if(get_next(kd, host))
 667             return 0;
 668     }
 669
 670     if (kd->flags & KD_CONFIG_EXISTS)
 671         return KRB5_KDC_UNREACH; /* XXX */
 672
 673     if(context->srv_lookup) {
 674         if((kd->flags & KD_SRV_UDP) == 0) {
 675             srv_get_hosts(context, kd, "udp", "kpasswd");
 676             kd->flags |= KD_SRV_UDP;
 677             if(get_next(kd, host))
 678                 return 0;
 679         }
 680         if((kd->flags & KD_SRV_TCP) == 0) {
 681             srv_get_hosts(context, kd, "tcp", "kpasswd");
 682             kd->flags |= KD_SRV_TCP;
 683             if(get_next(kd, host))
 684                 return 0;
 685         }
 686     }
 687
 688     /* no matches -> try admin */
 689
 690     if (krbhst_empty(kd)) {
 691         kd->flags = 0;
 692         kd->port  = kd->def_port;
 693         kd->get_next = admin_get_next;
 694         ret = (*kd->get_next)(context, kd, host);
 695         if (ret == 0)
 696             (*host)->proto = krbhst_get_default_proto(kd);
 697         return ret;
 698     }
 699
 700     return KRB5_KDC_UNREACH; /* XXX */
 701 }
 702
 703 static krb5_error_code
 704 krb524_get_next(krb5_context context,
 705                 struct krb5_krbhst_data *kd,
 706                 krb5_krbhst_info **host)
 707 {
 708     if((kd->flags & KD_CONFIG) == 0) {
 709         config_get_hosts(context, kd, "krb524_server");
 710         if(get_next(kd, host))
 711             return 0;
 712         kd->flags |= KD_CONFIG;
 713     }
 714
 715     if (kd->flags & KD_CONFIG_EXISTS)
 716         return KRB5_KDC_UNREACH; /* XXX */
 717
 718     if(context->srv_lookup) {
 719         if((kd->flags & KD_SRV_UDP) == 0) {
 720             srv_get_hosts(context, kd, "udp", "krb524");
 721             kd->flags |= KD_SRV_UDP;
 722             if(get_next(kd, host))
 723                 return 0;
 724         }
 725
 726         if((kd->flags & KD_SRV_TCP) == 0) {
 727             srv_get_hosts(context, kd, "tcp", "krb524");
 728             kd->flags |= KD_SRV_TCP;
 729             if(get_next(kd, host))
 730                 return 0;
 731         }
 732     }
 733
 734     /* no matches -> try kdc */
 735
 736     if (krbhst_empty(kd)) {
 737         kd->flags = 0;
 738         kd->port  = kd->def_port;
 739         kd->get_next = kdc_get_next;
 740         return (*kd->get_next)(context, kd, host);
 741     }
 742
 743     return KRB5_KDC_UNREACH; /* XXX */
 744 }
 745
 746 static struct krb5_krbhst_data*
 747 common_init(krb5_context context,
 748             const char *realm,
 749             int flags)
 750 {
 751     struct krb5_krbhst_data *kd;
 752
 753     if((kd = calloc(1, sizeof(*kd))) == NULL)
 754         return NULL;
 755
 756     if((kd->realm = strdup(realm)) == NULL) {
 757         free(kd);
 758         return NULL;
 759     }
 760
 761     /* For 'realms' without a . do not even think of going to DNS */
 762     if (!strchr(realm, '.'))
 763         kd->flags |= KD_CONFIG_EXISTS;
 764
 765     if (flags & KRB5_KRBHST_FLAGS_LARGE_MSG)
 766         kd->flags |= KD_LARGE_MSG;
 767     kd->end = kd->index = &kd->hosts;
 768     return kd;
 769 }
 770
 771 /*
 772  * initialize `handle' to look for hosts of type `type' in realm `realm'
 773  */
 774
 775 krb5_error_code KRB5_LIB_FUNCTION
 776 krb5_krbhst_init(krb5_context context,
 777                  const char *realm,
 778                  unsigned int type,
 779                  krb5_krbhst_handle *handle)
 780 {
 781     return krb5_krbhst_init_flags(context, realm, type, 0, handle);
 782 }
 783
 784 krb5_error_code KRB5_LIB_FUNCTION
 785 krb5_krbhst_init_flags(krb5_context context,
 786                        const char *realm,
 787                        unsigned int type,
 788                        int flags,
 789                        krb5_krbhst_handle *handle)
 790 {
 791     struct krb5_krbhst_data *kd;
 792     krb5_error_code (*next)(krb5_context, struct krb5_krbhst_data *,
 793                             krb5_krbhst_info **);
 794     int def_port;
 795
 796     switch(type) {
 797     case KRB5_KRBHST_KDC:
 798         next = kdc_get_next;
 799         def_port = ntohs(krb5_getportbyname (context, "kerberos", "udp", 88));
 800         break;
 801     case KRB5_KRBHST_ADMIN:
 802         next = admin_get_next;
 803         def_port = ntohs(krb5_getportbyname (context, "kerberos-adm",
 804                                              "tcp", 749));
 805         break;
 806     case KRB5_KRBHST_CHANGEPW:
 807         next = kpasswd_get_next;
 808         def_port = ntohs(krb5_getportbyname (context, "kpasswd", "udp",
 809                                              KPASSWD_PORT));
 810         break;
 811     case KRB5_KRBHST_KRB524:
 812         next = krb524_get_next;
 813         def_port = ntohs(krb5_getportbyname (context, "krb524", "udp", 4444));
 814         break;
 815     default:
 816         krb5_set_error_string(context, "unknown krbhst type (%u)", type);
 817         return ENOTTY;
 818     }
 819     if((kd = common_init(context, realm, flags)) == NULL)
 820         return ENOMEM;
 821     kd->get_next = next;
 822     kd->def_port = def_port;
 823     *handle = kd;
 824     return 0;
 825 }
 826
 827 /*
 828  * return the next host information from `handle' in `host'
 829  */
 830
 831 krb5_error_code KRB5_LIB_FUNCTION
 832 krb5_krbhst_next(krb5_context context,
 833                  krb5_krbhst_handle handle,
 834                  krb5_krbhst_info **host)
 835 {
 836     if(get_next(handle, host))
 837         return 0;
 838
 839     return (*handle->get_next)(context, handle, host);
 840 }
 841
 842 /*
 843  * return the next host information from `handle' as a host name
 844  * in `hostname' (or length `hostlen)
 845  */
 846
 847 krb5_error_code KRB5_LIB_FUNCTION
 848 krb5_krbhst_next_as_string(krb5_context context,
 849                            krb5_krbhst_handle handle,
 850                            char *hostname,
 851                            size_t hostlen)
 852 {
 853     krb5_error_code ret;
 854     krb5_krbhst_info *host;
 855     ret = krb5_krbhst_next(context, handle, &host);
 856     if(ret)
 857         return ret;
 858     return krb5_krbhst_format_string(context, host, hostname, hostlen);
 859 }
 860
 861
 862 void KRB5_LIB_FUNCTION
 863 krb5_krbhst_reset(krb5_context context, krb5_krbhst_handle handle)
 864 {
 865     handle->index = &handle->hosts;
 866 }
 867
 868 void KRB5_LIB_FUNCTION
 869 krb5_krbhst_free(krb5_context context, krb5_krbhst_handle handle)
 870 {
 871     krb5_krbhst_info *h, *next;
 872
 873     if (handle == NULL)
 874         return;
 875
 876     for (h = handle->hosts; h != NULL; h = next) {
 877         next = h->next;
 878         _krb5_free_krbhst_info(h);
 879     }
 880
 881     free(handle->realm);
 882     free(handle);
 883 }
 884
 885 /* backwards compatibility ahead */
 886
 887 static krb5_error_code
 888 gethostlist(krb5_context context, const char *realm,
 889             unsigned int type, char ***hostlist)
 890 {
 891     krb5_error_code ret;
 892     int nhost = 0;
 893     krb5_krbhst_handle handle;
 894     char host[MAXHOSTNAMELEN];
 895     krb5_krbhst_info *hostinfo;
 896
 897     ret = krb5_krbhst_init(context, realm, type, &handle);
 898     if (ret)
 899         return ret;
 900
 901     while(krb5_krbhst_next(context, handle, &hostinfo) == 0)
 902         nhost++;
 903     if(nhost == 0)
 904         return KRB5_KDC_UNREACH;
 905     *hostlist = calloc(nhost + 1, sizeof(**hostlist));
 906     if(*hostlist == NULL) {
 907         krb5_krbhst_free(context, handle);
 908         return ENOMEM;
 909     }
 910
 911     krb5_krbhst_reset(context, handle);
 912     nhost = 0;
 913     while(krb5_krbhst_next_as_string(context, handle,
 914                                      host, sizeof(host)) == 0) {
 915         if(((*hostlist)[nhost++] = strdup(host)) == NULL) {
 916             krb5_free_krbhst(context, *hostlist);
 917             krb5_krbhst_free(context, handle);
 918             return ENOMEM;
 919         }
 920     }
 921     (*hostlist)[nhost++] = NULL;
 922     krb5_krbhst_free(context, handle);
 923     return 0;
 924 }
 925
 926 /*
 927  * return an malloced list of kadmin-hosts for `realm' in `hostlist'
 928  */
 929
 930 krb5_error_code KRB5_LIB_FUNCTION
 931 krb5_get_krb_admin_hst (krb5_context context,
 932                         const krb5_realm *realm,
 933                         char ***hostlist)
 934 {
 935     return gethostlist(context, *realm, KRB5_KRBHST_ADMIN, hostlist);
 936 }
 937
 938 /*
 939  * return an malloced list of changepw-hosts for `realm' in `hostlist'
 940  */
 941
 942 krb5_error_code KRB5_LIB_FUNCTION
 943 krb5_get_krb_changepw_hst (krb5_context context,
 944                            const krb5_realm *realm,
 945                            char ***hostlist)
 946 {
 947     return gethostlist(context, *realm, KRB5_KRBHST_CHANGEPW, hostlist);
 948 }
 949
 950 /*
 951  * return an malloced list of 524-hosts for `realm' in `hostlist'
 952  */
 953
 954 krb5_error_code KRB5_LIB_FUNCTION
 955 krb5_get_krb524hst (krb5_context context,
 956                     const krb5_realm *realm,
 957                     char ***hostlist)
 958 {
 959     return gethostlist(context, *realm, KRB5_KRBHST_KRB524, hostlist);
 960 }
 961
 962
 963 /*
 964  * return an malloced list of KDC's for `realm' in `hostlist'
 965  */
 966
 967 krb5_error_code KRB5_LIB_FUNCTION
 968 krb5_get_krbhst (krb5_context context,
 969                  const krb5_realm *realm,
 970                  char ***hostlist)
 971 {
 972     return gethostlist(context, *realm, KRB5_KRBHST_KDC, hostlist);
 973 }
 974
 975 /*
 976  * free all the memory allocated in `hostlist'
 977  */
 978
 979 krb5_error_code KRB5_LIB_FUNCTION
 980 krb5_free_krbhst (krb5_context context,
 981                   char **hostlist)
 982 {
 983     char **p;
 984
 985     for (p = hostlist; *p; ++p)
 986         free (*p);
 987     free (hostlist);
 988     return 0;
 989 }