git.sur5r.net Git - openldap/blob - libraries/libldap/dnssrv.c

   1 /* $OpenLDAP$ */
   2 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
   3  *
   4  * Copyright 1998-2013 The OpenLDAP Foundation.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted only as authorized by the OpenLDAP
   9  * Public License.
  10  *
  11  * A copy of this license is available in the file LICENSE in the
  12  * top-level directory of the distribution or, alternatively, at
  13  * <http://www.OpenLDAP.org/license.html>.
  14  */
  15
  16 /*
  17  * locate LDAP servers using DNS SRV records.
  18  * Location code based on MIT Kerberos KDC location code.
  19  */
  20 #include "portable.h"
  21
  22 #include <stdio.h>
  23
  24 #include <ac/stdlib.h>
  25
  26 #include <ac/param.h>
  27 #include <ac/socket.h>
  28 #include <ac/string.h>
  29 #include <ac/time.h>
  30
  31 #include "ldap-int.h"
  32
  33 #ifdef HAVE_ARPA_NAMESER_H
  34 #include <arpa/nameser.h>
  35 #endif
  36 #ifdef HAVE_RESOLV_H
  37 #include <resolv.h>
  38 #endif
  39
  40 int ldap_dn2domain(
  41         LDAP_CONST char *dn_in,
  42         char **domainp)
  43 {
  44         int i, j;
  45         char *ndomain;
  46         LDAPDN dn = NULL;
  47         LDAPRDN rdn = NULL;
  48         LDAPAVA *ava = NULL;
  49         struct berval domain = BER_BVNULL;
  50         static const struct berval DC = BER_BVC("DC");
  51         static const struct berval DCOID = BER_BVC("0.9.2342.19200300.100.1.25");
  52
  53         assert( dn_in != NULL );
  54         assert( domainp != NULL );
  55
  56         *domainp = NULL;
  57
  58         if ( ldap_str2dn( dn_in, &dn, LDAP_DN_FORMAT_LDAP ) != LDAP_SUCCESS ) {
  59                 return -2;
  60         }
  61
  62         if( dn ) for( i=0; dn[i] != NULL; i++ ) {
  63                 rdn = dn[i];
  64
  65                 for( j=0; rdn[j] != NULL; j++ ) {
  66                         ava = rdn[j];
  67
  68                         if( rdn[j+1] == NULL &&
  69                                 (ava->la_flags & LDAP_AVA_STRING) &&
  70                                 ava->la_value.bv_len &&
  71                                 ( ber_bvstrcasecmp( &ava->la_attr, &DC ) == 0
  72                                 || ber_bvcmp( &ava->la_attr, &DCOID ) == 0 ) )
  73                         {
  74                                 if( domain.bv_len == 0 ) {
  75                                         ndomain = LDAP_REALLOC( domain.bv_val,
  76                                                 ava->la_value.bv_len + 1);
  77
  78                                         if( ndomain == NULL ) {
  79                                                 goto return_error;
  80                                         }
  81
  82                                         domain.bv_val = ndomain;
  83
  84                                         AC_MEMCPY( domain.bv_val, ava->la_value.bv_val,
  85                                                 ava->la_value.bv_len );
  86
  87                                         domain.bv_len = ava->la_value.bv_len;
  88                                         domain.bv_val[domain.bv_len] = '\0';
  89
  90                                 } else {
  91                                         ndomain = LDAP_REALLOC( domain.bv_val,
  92                                                 ava->la_value.bv_len + sizeof(".") + domain.bv_len );
  93
  94                                         if( ndomain == NULL ) {
  95                                                 goto return_error;
  96                                         }
  97
  98                                         domain.bv_val = ndomain;
  99                                         domain.bv_val[domain.bv_len++] = '.';
 100                                         AC_MEMCPY( &domain.bv_val[domain.bv_len],
 101                                                 ava->la_value.bv_val, ava->la_value.bv_len );
 102                                         domain.bv_len += ava->la_value.bv_len;
 103                                         domain.bv_val[domain.bv_len] = '\0';
 104                                 }
 105                         } else {
 106                                 domain.bv_len = 0;
 107                         }
 108                 }
 109         }
 110
 111
 112         if( domain.bv_len == 0 && domain.bv_val != NULL ) {
 113                 LDAP_FREE( domain.bv_val );
 114                 domain.bv_val = NULL;
 115         }
 116
 117         ldap_dnfree( dn );
 118         *domainp = domain.bv_val;
 119         return 0;
 120
 121 return_error:
 122         ldap_dnfree( dn );
 123         LDAP_FREE( domain.bv_val );
 124         return -1;
 125 }
 126
 127 int ldap_domain2dn(
 128         LDAP_CONST char *domain_in,
 129         char **dnp)
 130 {
 131         char *domain, *s, *tok_r, *dn, *dntmp;
 132         size_t loc;
 133
 134         assert( domain_in != NULL );
 135         assert( dnp != NULL );
 136
 137         domain = LDAP_STRDUP(domain_in);
 138         if (domain == NULL) {
 139                 return LDAP_NO_MEMORY;
 140         }
 141         dn = NULL;
 142         loc = 0;
 143
 144         for (s = ldap_pvt_strtok(domain, ".", &tok_r);
 145                 s != NULL;
 146                 s = ldap_pvt_strtok(NULL, ".", &tok_r))
 147         {
 148                 size_t len = strlen(s);
 149
 150                 dntmp = (char *) LDAP_REALLOC(dn, loc + sizeof(",dc=") + len );
 151                 if (dntmp == NULL) {
 152                     if (dn != NULL)
 153                         LDAP_FREE(dn);
 154                     LDAP_FREE(domain);
 155                     return LDAP_NO_MEMORY;
 156                 }
 157
 158                 dn = dntmp;
 159
 160                 if (loc > 0) {
 161                     /* not first time. */
 162                     strcpy(dn + loc, ",");
 163                     loc++;
 164                 }
 165                 strcpy(dn + loc, "dc=");
 166                 loc += sizeof("dc=")-1;
 167
 168                 strcpy(dn + loc, s);
 169                 loc += len;
 170     }
 171
 172         LDAP_FREE(domain);
 173         *dnp = dn;
 174         return LDAP_SUCCESS;
 175 }
 176
 177 /*
 178  * Lookup and return LDAP servers for domain (using the DNS
 179  * SRV record _ldap._tcp.domain).
 180  */
 181 int ldap_domain2hostlist(
 182         LDAP_CONST char *domain,
 183         char **list )
 184 {
 185 #ifdef HAVE_RES_QUERY
 186 #define DNSBUFSIZ (64*1024)
 187     char *request;
 188     char *hostlist = NULL;
 189     int rc, len, cur = 0;
 190     unsigned char reply[DNSBUFSIZ];
 191
 192         assert( domain != NULL );
 193         assert( list != NULL );
 194
 195         if( *domain == '\0' ) {
 196                 return LDAP_PARAM_ERROR;
 197         }
 198
 199     request = LDAP_MALLOC(strlen(domain) + sizeof("_ldap._tcp."));
 200     if (request == NULL) {
 201                 return LDAP_NO_MEMORY;
 202     }
 203     sprintf(request, "_ldap._tcp.%s", domain);
 204
 205     LDAP_MUTEX_LOCK(&ldap_int_resolv_mutex);
 206
 207     rc = LDAP_UNAVAILABLE;
 208 #ifdef NS_HFIXEDSZ
 209         /* Bind 8/9 interface */
 210     len = res_query(request, ns_c_in, ns_t_srv, reply, sizeof(reply));
 211 #       ifndef T_SRV
 212 #               define T_SRV ns_t_srv
 213 #       endif
 214 #else
 215         /* Bind 4 interface */
 216 #       ifndef T_SRV
 217 #               define T_SRV 33
 218 #       endif
 219
 220     len = res_query(request, C_IN, T_SRV, reply, sizeof(reply));
 221 #endif
 222     if (len >= 0) {
 223         unsigned char *p;
 224         char host[DNSBUFSIZ];
 225         int status;
 226         u_short port;
 227         /* int priority, weight; */
 228
 229         /* Parse out query */
 230         p = reply;
 231
 232 #ifdef NS_HFIXEDSZ
 233         /* Bind 8/9 interface */
 234         p += NS_HFIXEDSZ;
 235 #elif defined(HFIXEDSZ)
 236         /* Bind 4 interface w/ HFIXEDSZ */
 237         p += HFIXEDSZ;
 238 #else
 239         /* Bind 4 interface w/o HFIXEDSZ */
 240         p += sizeof(HEADER);
 241 #endif
 242
 243         status = dn_expand(reply, reply + len, p, host, sizeof(host));
 244         if (status < 0) {
 245             goto out;
 246         }
 247         p += status;
 248         p += 4;
 249
 250         while (p < reply + len) {
 251             int type, class, ttl, size;
 252             status = dn_expand(reply, reply + len, p, host, sizeof(host));
 253             if (status < 0) {
 254                 goto out;
 255             }
 256             p += status;
 257             type = (p[0] << 8) | p[1];
 258             p += 2;
 259             class = (p[0] << 8) | p[1];
 260             p += 2;
 261             ttl = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
 262             p += 4;
 263             size = (p[0] << 8) | p[1];
 264             p += 2;
 265             if (type == T_SRV) {
 266                 int buflen;
 267                 status = dn_expand(reply, reply + len, p + 6, host, sizeof(host));
 268                 if (status < 0) {
 269                     goto out;
 270                 }
 271                 /* ignore priority and weight for now */
 272                 /* priority = (p[0] << 8) | p[1]; */
 273                 /* weight = (p[2] << 8) | p[3]; */
 274                 port = (p[4] << 8) | p[5];
 275
 276                 if ( port == 0 || host[ 0 ] == '\0' ) {
 277                     goto add_size;
 278                 }
 279
 280                 buflen = strlen(host) + STRLENOF(":65355 ");
 281                 hostlist = (char *) LDAP_REALLOC(hostlist, cur + buflen + 1);
 282                 if (hostlist == NULL) {
 283                     rc = LDAP_NO_MEMORY;
 284                     goto out;
 285                 }
 286                 if (cur > 0) {
 287                     /* not first time around */
 288                     hostlist[cur++] = ' ';
 289                 }
 290                 cur += sprintf(&hostlist[cur], "%s:%hu", host, port);
 291             }
 292 add_size:;
 293             p += size;
 294         }
 295     }
 296     if (hostlist == NULL) {
 297         /* No LDAP servers found in DNS. */
 298         rc = LDAP_UNAVAILABLE;
 299         goto out;
 300     }
 301
 302     rc = LDAP_SUCCESS;
 303         *list = hostlist;
 304
 305   out:
 306     LDAP_MUTEX_UNLOCK(&ldap_int_resolv_mutex);
 307
 308     if (request != NULL) {
 309         LDAP_FREE(request);
 310     }
 311     if (rc != LDAP_SUCCESS && hostlist != NULL) {
 312         LDAP_FREE(hostlist);
 313     }
 314     return rc;
 315 #else
 316     return LDAP_NOT_SUPPORTED;
 317 #endif /* HAVE_RES_QUERY */
 318 }