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

   1 /* $OpenLDAP$ */
   2 /*
   3  * Copyright 1998-2002 The OpenLDAP Foundation, All Rights Reserved.
   4  * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
   5  */
   6
   7 /*
   8  * locate LDAP servers using DNS SRV records.
   9  * Location code based on MIT Kerberos KDC location code.
  10  */
  11 #include "portable.h"
  12
  13 #include <stdio.h>
  14
  15 #include <ac/stdlib.h>
  16
  17 #include <ac/param.h>
  18 #include <ac/socket.h>
  19 #include <ac/string.h>
  20 #include <ac/time.h>
  21
  22 #include "ldap-int.h"
  23
  24 #ifdef HAVE_ARPA_NAMESER_H
  25 #include <arpa/nameser.h>
  26 #endif
  27 #ifdef HAVE_RESOLV_H
  28 #include <resolv.h>
  29 #endif
  30
  31 /* Sometimes this is not defined. */
  32 #ifndef T_SRV
  33 #define T_SRV            33
  34 #endif                          /* T_SRV */
  35
  36 int ldap_dn2domain(
  37         LDAP_CONST char *dn_in,
  38         char **domainp)
  39 {
  40         int i;
  41         char *domain = NULL;
  42         char **dn;
  43
  44         if( dn_in == NULL || domainp == NULL ) {
  45                 return -1;
  46         }
  47
  48         dn = ldap_explode_dn( dn_in, 0 );
  49
  50         if( dn == NULL ) {
  51                 return -2;
  52         }
  53
  54         for( i=0; dn[i] != NULL; i++ ) {
  55                 char ** rdn = ldap_explode_rdn( dn[i], 0 );
  56
  57                 if( rdn == NULL || *rdn == NULL ) {
  58                         LDAP_FREE( rdn );
  59                         LDAP_FREE( domain );
  60                         LDAP_VFREE( dn );
  61                         return -3;
  62                 }
  63
  64
  65                 if( rdn[1] == NULL ) {
  66                         /*
  67                          * single-valued RDN
  68                          */
  69                         char *dc;
  70
  71 #define LDAP_DC "dc="
  72 #define LDAP_DCOID "0.9.2342.19200300.100.1.25="
  73
  74                         if( strncasecmp( rdn[0],
  75                                 LDAP_DC, sizeof(LDAP_DC)-1 ) == 0 )
  76                         {
  77                                 dc = &rdn[0][sizeof(LDAP_DC)-1];
  78
  79                         } else if( strncmp( rdn[0],
  80                                 LDAP_DCOID, sizeof(LDAP_DCOID)-1 ) == 0 )
  81                         {
  82                                 dc = &rdn[0][sizeof(LDAP_DCOID)-1];
  83
  84                         } else {
  85                                 dc = NULL;
  86                         }
  87
  88                         if( dc != NULL ) {
  89                                 char *ndomain;
  90
  91                                 if( *dc == '\0' ) {
  92                                         /* dc value is empty! */
  93                                         LDAP_FREE( rdn );
  94                                         LDAP_FREE( domain );
  95                                         LDAP_VFREE( dn );
  96                                         LDAP_VFREE( rdn );
  97                                         return -4;
  98                                 }
  99
 100                                 ndomain = LDAP_REALLOC( domain,
 101                                         ( domain == NULL ? 0 : strlen(domain) )
 102                                         + strlen(dc) + sizeof(".") );
 103
 104                                 if( ndomain == NULL ) {
 105                                         LDAP_FREE( rdn );
 106                                         LDAP_FREE( domain );
 107                                         LDAP_VFREE( dn );
 108                                         LDAP_VFREE( rdn );
 109                                         return -5;
 110                                 }
 111
 112                                 if( domain == NULL ) {
 113                                         ndomain[0] = '\0';
 114                                 } else {
 115                                         strcat( ndomain, "." );
 116                                 }
 117
 118                                 strcat( ndomain, dc );
 119
 120                                 domain = ndomain;
 121                                 continue;
 122                         }
 123                 }
 124
 125                 /*
 126                  * multi-valued RDN or fall thru
 127                  */
 128
 129                 LDAP_VFREE( rdn );
 130                 LDAP_FREE( domain );
 131                 domain = NULL;
 132         }
 133
 134         if( domain != NULL &&  *domain == '\0' ) {
 135                 LDAP_FREE( domain );
 136                 domain = NULL;
 137         }
 138
 139         *domainp = domain;
 140         return 0;
 141 }
 142
 143 int ldap_domain2dn(
 144         LDAP_CONST char *domain_in,
 145         char **dnp)
 146 {
 147     char *domain, *s, *tok_r, *dn;
 148     size_t loc;
 149
 150     if (domain_in == NULL || dnp == NULL) {
 151         return LDAP_NO_MEMORY;
 152     }
 153     domain = LDAP_STRDUP(domain_in);
 154     if (domain == NULL) {
 155         return LDAP_NO_MEMORY;
 156     }
 157     dn = NULL;
 158     loc = 0;
 159
 160     for (s = ldap_pvt_strtok(domain, ".", &tok_r);
 161          s != NULL;
 162          s = ldap_pvt_strtok(NULL, ".", &tok_r)) {
 163         size_t len = strlen(s);
 164
 165         dn = (char *) LDAP_REALLOC(dn, loc + sizeof(",dc=") + len );
 166         if (dn == NULL) {
 167             LDAP_FREE(domain);
 168             return LDAP_NO_MEMORY;
 169         }
 170         if (loc > 0) {
 171             /* not first time. */
 172             strcpy(dn + loc, ",");
 173             loc++;
 174         }
 175         strcpy(dn + loc, "dc=");
 176         loc += sizeof("dc=")-1;
 177
 178         strcpy(dn + loc, s);
 179         loc += len;
 180     }
 181
 182     LDAP_FREE(domain);
 183
 184     *dnp = dn;
 185
 186     return LDAP_SUCCESS;
 187 }
 188
 189 /*
 190  * Lookup and return LDAP servers for domain (using the DNS
 191  * SRV record _ldap._tcp.domain).
 192  */
 193 int ldap_domain2hostlist(
 194         LDAP_CONST char *domain,
 195         char **list )
 196 {
 197 #ifdef HAVE_RES_QUERY
 198     char *request;
 199     char *hostlist = NULL;
 200     int rc, len, cur = 0;
 201     unsigned char reply[1024];
 202
 203         assert( domain != NULL );
 204         assert( list != NULL );
 205
 206         if( *domain == '\0' ) {
 207                 return LDAP_PARAM_ERROR;
 208         }
 209
 210     request = LDAP_MALLOC(strlen(domain) + sizeof("_ldap._tcp."));
 211     if (request == NULL) {
 212                 return LDAP_NO_MEMORY;
 213     }
 214     sprintf(request, "_ldap._tcp.%s", domain);
 215
 216 #ifdef LDAP_R_COMPILE
 217     ldap_pvt_thread_mutex_lock(&ldap_int_resolv_mutex);
 218 #endif
 219
 220     rc = LDAP_UNAVAILABLE;
 221     len = res_query(request, C_IN, T_SRV, reply, sizeof(reply));
 222     if (len >= 0) {
 223         unsigned char *p;
 224         char host[1024];
 225         int status;
 226         u_short port;
 227         /* int priority, weight; */
 228
 229         /* Parse out query */
 230         p = reply;
 231         p += sizeof(HEADER);
 232         status = dn_expand(reply, reply + len, p, host, sizeof(host));
 233         if (status < 0) {
 234             goto out;
 235         }
 236         p += status;
 237         p += 4;
 238
 239         while (p < reply + len) {
 240             int type, class, ttl, size;
 241             status = dn_expand(reply, reply + len, p, host, sizeof(host));
 242             if (status < 0) {
 243                 goto out;
 244             }
 245             p += status;
 246             type = (p[0] << 8) | p[1];
 247             p += 2;
 248             class = (p[0] << 8) | p[1];
 249             p += 2;
 250             ttl = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
 251             p += 4;
 252             size = (p[0] << 8) | p[1];
 253             p += 2;
 254             if (type == T_SRV) {
 255                 int buflen;
 256                 status = dn_expand(reply, reply + len, p + 6, host, sizeof(host));
 257                 if (status < 0) {
 258                     goto out;
 259                 }
 260                 /* ignore priority and weight for now */
 261                 /* priority = (p[0] << 8) | p[1]; */
 262                 /* weight = (p[2] << 8) | p[3]; */
 263                 port = (p[4] << 8) | p[5];
 264
 265                 buflen = strlen(host) + sizeof(":65355");
 266                 hostlist = (char *) LDAP_REALLOC(hostlist, cur + buflen);
 267                 if (hostlist == NULL) {
 268                     rc = LDAP_NO_MEMORY;
 269                     goto out;
 270                 }
 271                 if (cur > 0) {
 272                     /* not first time around */
 273                     hostlist[cur++] = ' ';
 274                 }
 275                 cur += sprintf(&hostlist[cur], "%s:%hd", host, port);
 276             }
 277             p += size;
 278         }
 279     }
 280     if (hostlist == NULL) {
 281         /* No LDAP servers found in DNS. */
 282         rc = LDAP_UNAVAILABLE;
 283         goto out;
 284     }
 285
 286     rc = LDAP_SUCCESS;
 287         *list = hostlist;
 288
 289   out:
 290 #ifdef LDAP_R_COMPILE
 291     ldap_pvt_thread_mutex_unlock(&ldap_int_resolv_mutex);
 292 #endif
 293
 294     if (request != NULL) {
 295         LDAP_FREE(request);
 296     }
 297     if (rc != LDAP_SUCCESS && hostlist != NULL) {
 298         LDAP_FREE(hostlist);
 299     }
 300     return rc;
 301 #else
 302     return LDAP_NOT_SUPPORTED;
 303 #endif /* HAVE_RES_QUERY */
 304 }