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 uint8_t werr_to_dns_err(WERROR werr)
  34 {
  35         if (W_ERROR_EQUAL(WERR_OK, werr)) {
  36                 return DNS_RCODE_OK;
  37         } else if (W_ERROR_EQUAL(DNS_ERR(FORMAT_ERROR), werr)) {
  38                 return DNS_RCODE_FORMERR;
  39         } else if (W_ERROR_EQUAL(DNS_ERR(SERVER_FAILURE), werr)) {
  40                 return DNS_RCODE_SERVFAIL;
  41         } else if (W_ERROR_EQUAL(DNS_ERR(NAME_ERROR), werr)) {
  42                 return DNS_RCODE_NXDOMAIN;
  43         } else if (W_ERROR_EQUAL(DNS_ERR(NOT_IMPLEMENTED), werr)) {
  44                 return DNS_RCODE_NOTIMP;
  45         } else if (W_ERROR_EQUAL(DNS_ERR(REFUSED), werr)) {
  46                 return DNS_RCODE_REFUSED;
  47         } else if (W_ERROR_EQUAL(DNS_ERR(YXDOMAIN), werr)) {
  48                 return DNS_RCODE_YXDOMAIN;
  49         } else if (W_ERROR_EQUAL(DNS_ERR(YXRRSET), werr)) {
  50                 return DNS_RCODE_YXRRSET;
  51         } else if (W_ERROR_EQUAL(DNS_ERR(NXRRSET), werr)) {
  52                 return DNS_RCODE_NXRRSET;
  53         } else if (W_ERROR_EQUAL(DNS_ERR(NOTAUTH), werr)) {
  54                 return DNS_RCODE_NOTAUTH;
  55         } else if (W_ERROR_EQUAL(DNS_ERR(NOTZONE), werr)) {
  56                 return DNS_RCODE_NOTZONE;
  57         }
  58         DEBUG(5, ("No mapping exists for %%s\n"));
  59         return DNS_RCODE_SERVFAIL;
  60 }
  61
  62 bool dns_name_match(const char *zone, const char *name, size_t *host_part_len)
  63 {
  64         size_t zl = strlen(zone);
  65         size_t nl = strlen(name);
  66         ssize_t zi, ni;
  67         static const size_t fixup = 'a' - 'A';
  68
  69         if (zl > nl) {
  70                 return false;
  71         }
  72
  73         for (zi = zl, ni = nl; zi >= 0; zi--, ni--) {
  74                 char zc = zone[zi];
  75                 char nc = name[ni];
  76
  77                 /* convert to lower case */
  78                 if (zc >= 'A' && zc <= 'Z') {
  79                         zc += fixup;
  80                 }
  81                 if (nc >= 'A' && nc <= 'Z') {
  82                         nc += fixup;
  83                 }
  84
  85                 if (zc != nc) {
  86                         return false;
  87                 }
  88         }
  89
  90         if (ni >= 0) {
  91                 if (name[ni] != '.') {
  92                         return false;
  93                 }
  94
  95                 ni--;
  96         }
  97
  98         *host_part_len = ni+1;
  99
 100         return true;
 101 }
 102
 103 /* Names are equal if they match and there's nothing left over */
 104 bool dns_name_equal(const char *name1, const char *name2)
 105 {
 106         size_t host_part_len;
 107         bool ret = dns_name_match(name1, name2, &host_part_len);
 108
 109         return ret && (host_part_len == 0);
 110 }
 111
 112 /*
 113   see if two dns records match
 114  */
 115 bool dns_records_match(struct dnsp_DnssrvRpcRecord *rec1,
 116                        struct dnsp_DnssrvRpcRecord *rec2)
 117 {
 118         if (rec1->wType != rec2->wType) {
 119                 return false;
 120         }
 121
 122         /* see if the data matches */
 123         switch (rec1->wType) {
 124         case DNS_TYPE_A:
 125                 return strcmp(rec1->data.ipv4, rec2->data.ipv4) == 0;
 126         case DNS_TYPE_AAAA:
 127                 return strcmp(rec1->data.ipv6, rec2->data.ipv6) == 0;
 128         case DNS_TYPE_CNAME:
 129                 return dns_name_equal(rec1->data.cname, rec2->data.cname);
 130         case DNS_TYPE_TXT:
 131                 return strcmp(rec1->data.txt, rec2->data.txt) == 0;
 132         case DNS_TYPE_PTR:
 133                 return strcmp(rec1->data.ptr, rec2->data.ptr) == 0;
 134         case DNS_TYPE_NS:
 135                 return dns_name_equal(rec1->data.ns, rec2->data.ns);
 136
 137         case DNS_TYPE_SRV:
 138                 return rec1->data.srv.wPriority == rec2->data.srv.wPriority &&
 139                         rec1->data.srv.wWeight  == rec2->data.srv.wWeight &&
 140                         rec1->data.srv.wPort    == rec2->data.srv.wPort &&
 141                         dns_name_equal(rec1->data.srv.nameTarget, rec2->data.srv.nameTarget);
 142
 143         case DNS_TYPE_MX:
 144                 return rec1->data.mx.wPriority == rec2->data.mx.wPriority &&
 145                         dns_name_equal(rec1->data.mx.nameTarget, rec2->data.mx.nameTarget);
 146
 147         case DNS_TYPE_HINFO:
 148                 return strcmp(rec1->data.hinfo.cpu, rec2->data.hinfo.cpu) == 0 &&
 149                         strcmp(rec1->data.hinfo.os, rec2->data.hinfo.os) == 0;
 150
 151         case DNS_TYPE_SOA:
 152                 return dns_name_equal(rec1->data.soa.mname, rec2->data.soa.mname) &&
 153                         dns_name_equal(rec1->data.soa.rname, rec2->data.soa.rname) &&
 154                         rec1->data.soa.serial == rec2->data.soa.serial &&
 155                         rec1->data.soa.refresh == rec2->data.soa.refresh &&
 156                         rec1->data.soa.retry == rec2->data.soa.retry &&
 157                         rec1->data.soa.expire == rec2->data.soa.expire &&
 158                         rec1->data.soa.minimum == rec2->data.soa.minimum;
 159         default:
 160                 break;
 161         }
 162
 163         return false;
 164 }
 165
 166 WERROR dns_lookup_records(struct dns_server *dns,
 167                           TALLOC_CTX *mem_ctx,
 168                           struct ldb_dn *dn,
 169                           struct dnsp_DnssrvRpcRecord **records,
 170                           uint16_t *rec_count)
 171 {
 172         static const char * const attrs[] = { "dnsRecord", NULL};
 173         struct ldb_message_element *el;
 174         uint16_t ri;
 175         int ret;
 176         struct ldb_message *msg = NULL;
 177         struct dnsp_DnssrvRpcRecord *recs;
 178
 179         ret = dsdb_search_one(dns->samdb, mem_ctx, &msg, dn,
 180                               LDB_SCOPE_BASE, attrs, 0, "%s", "(objectClass=dnsNode)");
 181         if (ret != LDB_SUCCESS) {
 182                 /* TODO: we need to check if there's a glue record we need to
 183                  * create a referral to */
 184                 return DNS_ERR(NAME_ERROR);
 185         }
 186
 187         el = ldb_msg_find_element(msg, attrs[0]);
 188         if (el == NULL) {
 189                 *records = NULL;
 190                 *rec_count = 0;
 191                 return WERR_OK;
 192         }
 193
 194         recs = talloc_zero_array(mem_ctx, struct dnsp_DnssrvRpcRecord, el->num_values);
 195         W_ERROR_HAVE_NO_MEMORY(recs);
 196         for (ri = 0; ri < el->num_values; ri++) {
 197                 struct ldb_val *v = &el->values[ri];
 198                 enum ndr_err_code ndr_err;
 199
 200                 ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
 201                                 (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
 202                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 203                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 204                         return DNS_ERR(SERVER_FAILURE);
 205                 }
 206         }
 207         *records = recs;
 208         *rec_count = el->num_values;
 209         return WERR_OK;
 210 }
 211
 212 WERROR dns_name2dn(struct dns_server *dns,
 213                    TALLOC_CTX *mem_ctx,
 214                    const char *name,
 215                    struct ldb_dn **_dn)
 216 {
 217         struct ldb_dn *base;
 218         struct ldb_dn *dn;
 219         const struct dns_server_zone *z;
 220         size_t host_part_len = 0;
 221
 222         if (name == NULL) {
 223                 return DNS_ERR(FORMAT_ERROR);
 224         }
 225
 226         /*TODO: Check if 'name' is a valid DNS name */
 227
 228         if (strcmp(name, "") == 0) {
 229                 base = ldb_get_default_basedn(dns->samdb);
 230                 dn = ldb_dn_copy(mem_ctx, base);
 231                 ldb_dn_add_child_fmt(dn, "DC=@,DC=RootDNSServers,CN=MicrosoftDNS,CN=System");
 232                 *_dn = dn;
 233                 return WERR_OK;
 234         }
 235
 236         for (z = dns->zones; z != NULL; z = z->next) {
 237                 bool match;
 238
 239                 match = dns_name_match(z->name, name, &host_part_len);
 240                 if (match) {
 241                         break;
 242                 }
 243         }
 244
 245         if (z == NULL) {
 246                 return DNS_ERR(NAME_ERROR);
 247         }
 248
 249         if (host_part_len == 0) {
 250                 dn = ldb_dn_copy(mem_ctx, z->dn);
 251                 ldb_dn_add_child_fmt(dn, "DC=@");
 252                 *_dn = dn;
 253                 return WERR_OK;
 254         }
 255
 256         dn = ldb_dn_copy(mem_ctx, z->dn);
 257         ldb_dn_add_child_fmt(dn, "DC=%*.*s", (int)host_part_len, (int)host_part_len, name);
 258         *_dn = dn;
 259         return WERR_OK;
 260 }