source4/dns_server/dns_utils.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server utils
   5
   6    Copyright (C) 2010 Kai Blin  <kai@samba.org>
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "libcli/util/ntstatus.h"
  24 #include "libcli/util/werror.h"
  25 #include "librpc/ndr/libndr.h"
  26 #include "librpc/gen_ndr/ndr_dns.h"
  27 #include "librpc/gen_ndr/ndr_dnsp.h"
  28 #include <ldb.h>
  29 #include "dsdb/samdb/samdb.h"
  30 #include "dsdb/common/util.h"
  31 #include "dns_server/dns_server.h"
  32
  33 #undef DBGC_CLASS
  34 #define DBGC_CLASS DBGC_DNS
  35
  36 bool dns_name_match(const char *zone, const char *name, size_t *host_part_len)
  37 {
  38         size_t zl = strlen(zone);
  39         size_t nl = strlen(name);
  40         ssize_t zi, ni;
  41         static const size_t fixup = 'a' - 'A';
  42
  43         if (zl > nl) {
  44                 return false;
  45         }
  46
  47         for (zi = zl, ni = nl; zi >= 0; zi--, ni--) {
  48                 char zc = zone[zi];
  49                 char nc = name[ni];
  50
  51                 /* convert to lower case */
  52                 if (zc >= 'A' && zc <= 'Z') {
  53                         zc += fixup;
  54                 }
  55                 if (nc >= 'A' && nc <= 'Z') {
  56                         nc += fixup;
  57                 }
  58
  59                 if (zc != nc) {
  60                         return false;
  61                 }
  62         }
  63
  64         if (ni >= 0) {
  65                 if (name[ni] != '.') {
  66                         return false;
  67                 }
  68
  69                 ni--;
  70         }
  71
  72         *host_part_len = ni+1;
  73
  74         return true;
  75 }
  76
  77 /* Names are equal if they match and there's nothing left over */
  78 bool dns_name_equal(const char *name1, const char *name2)
  79 {
  80         size_t host_part_len;
  81         bool ret = dns_name_match(name1, name2, &host_part_len);
  82
  83         return ret && (host_part_len == 0);
  84 }
  85
  86 /*
  87   see if two dns records match
  88  */
  89 bool dns_records_match(struct dnsp_DnssrvRpcRecord *rec1,
  90                        struct dnsp_DnssrvRpcRecord *rec2)
  91 {
  92         bool status;
  93         int i;
  94
  95         if (rec1->wType != rec2->wType) {
  96                 return false;
  97         }
  98
  99         /* see if the data matches */
 100         switch (rec1->wType) {
 101         case DNS_TYPE_A:
 102                 return strcmp(rec1->data.ipv4, rec2->data.ipv4) == 0;
 103         case DNS_TYPE_AAAA:
 104                 return strcmp(rec1->data.ipv6, rec2->data.ipv6) == 0;
 105         case DNS_TYPE_CNAME:
 106                 return dns_name_equal(rec1->data.cname, rec2->data.cname);
 107         case DNS_TYPE_TXT:
 108                 if (rec1->data.txt.count != rec2->data.txt.count) {
 109                         return false;
 110                 }
 111                 status = true;
 112                 for (i=0; i<rec1->data.txt.count; i++) {
 113                         status = status && (strcmp(rec1->data.txt.str[i],
 114                                                 rec2->data.txt.str[i]) == 0);
 115                 }
 116                 return status;
 117         case DNS_TYPE_PTR:
 118                 return strcmp(rec1->data.ptr, rec2->data.ptr) == 0;
 119         case DNS_TYPE_NS:
 120                 return dns_name_equal(rec1->data.ns, rec2->data.ns);
 121
 122         case DNS_TYPE_SRV:
 123                 return rec1->data.srv.wPriority == rec2->data.srv.wPriority &&
 124                         rec1->data.srv.wWeight  == rec2->data.srv.wWeight &&
 125                         rec1->data.srv.wPort    == rec2->data.srv.wPort &&
 126                         dns_name_equal(rec1->data.srv.nameTarget, rec2->data.srv.nameTarget);
 127
 128         case DNS_TYPE_MX:
 129                 return rec1->data.mx.wPriority == rec2->data.mx.wPriority &&
 130                         dns_name_equal(rec1->data.mx.nameTarget, rec2->data.mx.nameTarget);
 131
 132         case DNS_TYPE_HINFO:
 133                 return strcmp(rec1->data.hinfo.cpu, rec2->data.hinfo.cpu) == 0 &&
 134                         strcmp(rec1->data.hinfo.os, rec2->data.hinfo.os) == 0;
 135
 136         case DNS_TYPE_SOA:
 137                 return dns_name_equal(rec1->data.soa.mname, rec2->data.soa.mname) &&
 138                         dns_name_equal(rec1->data.soa.rname, rec2->data.soa.rname) &&
 139                         rec1->data.soa.serial == rec2->data.soa.serial &&
 140                         rec1->data.soa.refresh == rec2->data.soa.refresh &&
 141                         rec1->data.soa.retry == rec2->data.soa.retry &&
 142                         rec1->data.soa.expire == rec2->data.soa.expire &&
 143                         rec1->data.soa.minimum == rec2->data.soa.minimum;
 144         default:
 145                 break;
 146         }
 147
 148         return false;
 149 }
 150
 151 WERROR dns_lookup_records(struct dns_server *dns,
 152                           TALLOC_CTX *mem_ctx,
 153                           struct ldb_dn *dn,
 154                           struct dnsp_DnssrvRpcRecord **records,
 155                           uint16_t *rec_count)
 156 {
 157         return dns_common_lookup(dns->samdb, mem_ctx, dn, records, rec_count);
 158 }
 159
 160 WERROR dns_replace_records(struct dns_server *dns,
 161                            TALLOC_CTX *mem_ctx,
 162                            struct ldb_dn *dn,
 163                            bool needs_add,
 164                            struct dnsp_DnssrvRpcRecord *records,
 165                            uint16_t rec_count)
 166 {
 167         struct ldb_message_element *el;
 168         uint16_t i;
 169         int ret;
 170         struct ldb_message *msg = NULL;
 171
 172         msg = ldb_msg_new(mem_ctx);
 173         W_ERROR_HAVE_NO_MEMORY(msg);
 174
 175         msg->dn = dn;
 176
 177         ret = ldb_msg_add_empty(msg, "dnsRecord", LDB_FLAG_MOD_REPLACE, &el);
 178         if (ret != LDB_SUCCESS) {
 179                 return DNS_ERR(SERVER_FAILURE);
 180         }
 181
 182         el->values = talloc_zero_array(el, struct ldb_val, rec_count);
 183         if (rec_count > 0) {
 184                 W_ERROR_HAVE_NO_MEMORY(el->values);
 185         }
 186
 187         for (i = 0; i < rec_count; i++) {
 188                 static const struct dnsp_DnssrvRpcRecord zero;
 189                 struct ldb_val *v = &el->values[el->num_values];
 190                 enum ndr_err_code ndr_err;
 191
 192                 if (memcmp(&records[i], &zero, sizeof(zero)) == 0) {
 193                         continue;
 194                 }
 195                 ndr_err = ndr_push_struct_blob(v, el->values, &records[i],
 196                                 (ndr_push_flags_fn_t)ndr_push_dnsp_DnssrvRpcRecord);
 197                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 198                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 199                         return DNS_ERR(SERVER_FAILURE);
 200                 }
 201                 el->num_values++;
 202         }
 203
 204
 205         if (el->num_values == 0) {
 206                 if (needs_add) {
 207                         return WERR_OK;
 208                 }
 209                 /* TODO: Delete object? */
 210                 el->flags = LDB_FLAG_MOD_DELETE;
 211         }
 212
 213         if (needs_add) {
 214                 ret = ldb_msg_add_string(msg, "objectClass", "dnsNode");
 215                 if (ret != LDB_SUCCESS) {
 216                         return DNS_ERR(SERVER_FAILURE);
 217                 }
 218
 219                 ret = ldb_add(dns->samdb, msg);
 220                 if (ret != LDB_SUCCESS) {
 221                         return DNS_ERR(SERVER_FAILURE);
 222                 }
 223
 224                 return WERR_OK;
 225         }
 226
 227         ret = ldb_modify(dns->samdb, msg);
 228         if (ret != LDB_SUCCESS) {
 229                 return DNS_ERR(SERVER_FAILURE);
 230         }
 231
 232         return WERR_OK;
 233 }
 234
 235 bool dns_authorative_for_zone(struct dns_server *dns,
 236                               const char *name)
 237 {
 238         const struct dns_server_zone *z;
 239         size_t host_part_len = 0;
 240
 241         if (name == NULL) {
 242                 return false;
 243         }
 244
 245         if (strcmp(name, "") == 0) {
 246                 return true;
 247         }
 248         for (z = dns->zones; z != NULL; z = z->next) {
 249                 bool match;
 250
 251                 match = dns_name_match(z->name, name, &host_part_len);
 252                 if (match) {
 253                         break;
 254                 }
 255         }
 256         if (z == NULL) {
 257                 return false;
 258         }
 259
 260         return true;
 261 }
 262
 263 WERROR dns_name2dn(struct dns_server *dns,
 264                    TALLOC_CTX *mem_ctx,
 265                    const char *name,
 266                    struct ldb_dn **_dn)
 267 {
 268         struct ldb_dn *base;
 269         struct ldb_dn *dn;
 270         const struct dns_server_zone *z;
 271         size_t host_part_len = 0;
 272
 273         if (name == NULL) {
 274                 return DNS_ERR(FORMAT_ERROR);
 275         }
 276
 277         /*TODO: Check if 'name' is a valid DNS name */
 278
 279         if (strcmp(name, "") == 0) {
 280                 base = ldb_get_default_basedn(dns->samdb);
 281                 dn = ldb_dn_copy(mem_ctx, base);
 282                 ldb_dn_add_child_fmt(dn, "DC=@,DC=RootDNSServers,CN=MicrosoftDNS,CN=System");
 283                 *_dn = dn;
 284                 return WERR_OK;
 285         }
 286
 287         for (z = dns->zones; z != NULL; z = z->next) {
 288                 bool match;
 289
 290                 match = dns_name_match(z->name, name, &host_part_len);
 291                 if (match) {
 292                         break;
 293                 }
 294         }
 295
 296         if (z == NULL) {
 297                 return DNS_ERR(NAME_ERROR);
 298         }
 299
 300         if (host_part_len == 0) {
 301                 dn = ldb_dn_copy(mem_ctx, z->dn);
 302                 ldb_dn_add_child_fmt(dn, "DC=@");
 303                 *_dn = dn;
 304                 return WERR_OK;
 305         }
 306
 307         dn = ldb_dn_copy(mem_ctx, z->dn);
 308         ldb_dn_add_child_fmt(dn, "DC=%*.*s", (int)host_part_len, (int)host_part_len, name);
 309         *_dn = dn;
 310         return WERR_OK;
 311 }
 312
 313 WERROR dns_generate_options(struct dns_server *dns,
 314                             TALLOC_CTX *mem_ctx,
 315                             struct dns_res_rec **options)
 316 {
 317         struct dns_res_rec *o;
 318
 319         o = talloc_zero(mem_ctx, struct dns_res_rec);
 320         if (o == NULL) {
 321                 return WERR_NOMEM;
 322         }
 323         o->name = '\0';
 324         o->rr_type = DNS_QTYPE_OPT;
 325         /* This is ugly, but RFC2671 wants the payload size in this field */
 326         o->rr_class = (enum dns_qclass) dns->max_payload;
 327         o->ttl = 0;
 328         o->length = 0;
 329
 330         *options = o;
 331         return WERR_OK;
 332 }