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,
 158                                  records, rec_count, NULL);
 159 }
 160
 161 WERROR dns_replace_records(struct dns_server *dns,
 162                            TALLOC_CTX *mem_ctx,
 163                            struct ldb_dn *dn,
 164                            bool needs_add,
 165                            struct dnsp_DnssrvRpcRecord *records,
 166                            uint16_t rec_count)
 167 {
 168         /* TODO: Autogenerate this somehow */
 169         uint32_t dwSerial = 110;
 170         return dns_common_replace(dns->samdb, mem_ctx, dn,
 171                                   needs_add, dwSerial, records, rec_count);
 172 }
 173
 174 bool dns_authorative_for_zone(struct dns_server *dns,
 175                               const char *name)
 176 {
 177         const struct dns_server_zone *z;
 178         size_t host_part_len = 0;
 179
 180         if (name == NULL) {
 181                 return false;
 182         }
 183
 184         if (strcmp(name, "") == 0) {
 185                 return true;
 186         }
 187         for (z = dns->zones; z != NULL; z = z->next) {
 188                 bool match;
 189
 190                 match = dns_name_match(z->name, name, &host_part_len);
 191                 if (match) {
 192                         break;
 193                 }
 194         }
 195         if (z == NULL) {
 196                 return false;
 197         }
 198
 199         return true;
 200 }
 201
 202 const char *dns_get_authoritative_zone(struct dns_server *dns,
 203                                        const char *name)
 204 {
 205         const struct dns_server_zone *z;
 206         size_t host_part_len = 0;
 207
 208         for (z = dns->zones; z != NULL; z = z->next) {
 209                 bool match;
 210                 match = dns_name_match(z->name, name, &host_part_len);
 211                 if (match) {
 212                         return z->name;
 213                 }
 214         }
 215         return NULL;
 216 }
 217
 218 WERROR dns_name2dn(struct dns_server *dns,
 219                    TALLOC_CTX *mem_ctx,
 220                    const char *name,
 221                    struct ldb_dn **_dn)
 222 {
 223         struct ldb_dn *base;
 224         struct ldb_dn *dn;
 225         const struct dns_server_zone *z;
 226         size_t host_part_len = 0;
 227
 228         if (name == NULL) {
 229                 return DNS_ERR(FORMAT_ERROR);
 230         }
 231
 232         /*TODO: Check if 'name' is a valid DNS name */
 233
 234         if (strcmp(name, "") == 0) {
 235                 base = ldb_get_default_basedn(dns->samdb);
 236                 dn = ldb_dn_copy(mem_ctx, base);
 237                 ldb_dn_add_child_fmt(dn, "DC=@,DC=RootDNSServers,CN=MicrosoftDNS,CN=System");
 238                 *_dn = dn;
 239                 return WERR_OK;
 240         }
 241
 242         for (z = dns->zones; z != NULL; z = z->next) {
 243                 bool match;
 244
 245                 match = dns_name_match(z->name, name, &host_part_len);
 246                 if (match) {
 247                         break;
 248                 }
 249         }
 250
 251         if (z == NULL) {
 252                 return DNS_ERR(NAME_ERROR);
 253         }
 254
 255         if (host_part_len == 0) {
 256                 dn = ldb_dn_copy(mem_ctx, z->dn);
 257                 ldb_dn_add_child_fmt(dn, "DC=@");
 258                 *_dn = dn;
 259                 return WERR_OK;
 260         }
 261
 262         dn = ldb_dn_copy(mem_ctx, z->dn);
 263         ldb_dn_add_child_fmt(dn, "DC=%*.*s", (int)host_part_len, (int)host_part_len, name);
 264         *_dn = dn;
 265         return WERR_OK;
 266 }
 267
 268 WERROR dns_generate_options(struct dns_server *dns,
 269                             TALLOC_CTX *mem_ctx,
 270                             struct dns_res_rec **options)
 271 {
 272         struct dns_res_rec *o;
 273
 274         o = talloc_zero(mem_ctx, struct dns_res_rec);
 275         if (o == NULL) {
 276                 return WERR_NOMEM;
 277         }
 278         o->name = '\0';
 279         o->rr_type = DNS_QTYPE_OPT;
 280         /* This is ugly, but RFC2671 wants the payload size in this field */
 281         o->rr_class = (enum dns_qclass) dns->max_payload;
 282         o->ttl = 0;
 283         o->length = 0;
 284
 285         *options = o;
 286         return WERR_OK;
 287 }