source4/dns_server/dns_query.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server handler for queries
   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/werror.h"
  24 #include "librpc/ndr/libndr.h"
  25 #include "librpc/gen_ndr/ndr_dns.h"
  26 #include "librpc/gen_ndr/ndr_dnsp.h"
  27 #include <ldb.h>
  28 #include "dsdb/samdb/samdb.h"
  29 #include "dsdb/common/util.h"
  30 #include "dns_server/dns_server.h"
  31
  32 static WERROR handle_question(struct dns_server *dns,
  33                               TALLOC_CTX *mem_ctx,
  34                               const struct dns_name_question *question,
  35                               struct dns_res_rec **answers, uint16_t *ancount)
  36 {
  37         struct dns_res_rec *ans;
  38         struct ldb_dn *dn = NULL;
  39         WERROR werror;
  40         static const char * const attrs[] = { "dnsRecord", NULL};
  41         int ret;
  42         uint16_t ai = *ancount;
  43         unsigned int ri;
  44         struct ldb_message *msg = NULL;
  45         struct dnsp_DnssrvRpcRecord *recs;
  46         struct ldb_message_element *el;
  47
  48         werror = dns_name2dn(dns, mem_ctx, question->name, &dn);
  49         W_ERROR_NOT_OK_RETURN(werror);
  50
  51         ret = dsdb_search_one(dns->samdb, mem_ctx, &msg, dn,
  52                               LDB_SCOPE_BASE, attrs, 0, "%s", "(objectClass=dnsNode)");
  53         if (ret != LDB_SUCCESS) {
  54                 return DNS_ERR(NAME_ERROR);
  55         }
  56
  57         el = ldb_msg_find_element(msg, attrs[0]);
  58         if (el == NULL) {
  59                 return DNS_ERR(NAME_ERROR);
  60         }
  61
  62         recs = talloc_array(mem_ctx, struct dnsp_DnssrvRpcRecord, el->num_values);
  63         for (ri = 0; ri < el->num_values; ri++) {
  64                 struct ldb_val *v = &el->values[ri];
  65                 enum ndr_err_code ndr_err;
  66
  67                 ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
  68                                 (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
  69                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  70                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
  71                         return DNS_ERR(SERVER_FAILURE);
  72                 }
  73         }
  74
  75         ans = talloc_realloc(mem_ctx, *answers, struct dns_res_rec,
  76                              ai + el->num_values);
  77         W_ERROR_HAVE_NO_MEMORY(ans);
  78
  79         switch (question->question_type) {
  80         case DNS_QTYPE_CNAME:
  81                 for (ri = 0; ri < el->num_values; ri++) {
  82                         if (recs[ri].wType != question->question_type) {
  83                                 continue;
  84                         }
  85
  86                         ZERO_STRUCT(ans[ai]);
  87                         ans[ai].name = talloc_strdup(ans, question->name);
  88                         ans[ai].rr_type = DNS_QTYPE_CNAME;
  89                         ans[ai].rr_class = DNS_QCLASS_IN;
  90                         ans[ai].ttl = recs[ri].dwTtlSeconds;
  91                         ans[ai].length = UINT16_MAX;
  92                         ans[ai].rdata.cname_record = talloc_strdup(ans, recs[ri].data.cname);
  93                         ai++;
  94                 }
  95                 break;
  96         case DNS_QTYPE_A:
  97                 for (ri = 0; ri < el->num_values; ri++) {
  98                         if (recs[ri].wType != question->question_type) {
  99                                 continue;
 100                         }
 101
 102                         /* TODO: if the record actually is a DNS_QTYPE_A */
 103
 104                         ZERO_STRUCT(ans[ai]);
 105                         ans[ai].name = talloc_strdup(ans, question->name);
 106                         ans[ai].rr_type = DNS_QTYPE_A;
 107                         ans[ai].rr_class = DNS_QCLASS_IN;
 108                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 109                         ans[ai].length = UINT16_MAX;
 110                         ans[ai].rdata.ipv4_record = talloc_strdup(ans, recs[ri].data.ipv4);
 111                         ai++;
 112                 }
 113                 break;
 114         case DNS_QTYPE_AAAA:
 115                 for (ri = 0; ri < el->num_values; ri++) {
 116                         if (recs[ri].wType != question->question_type) {
 117                                 continue;
 118                         }
 119
 120                         ZERO_STRUCT(ans[ai]);
 121                         ans[ai].name = talloc_strdup(ans, question->name);
 122                         ans[ai].rr_type = DNS_QTYPE_AAAA;
 123                         ans[ai].rr_class = DNS_QCLASS_IN;
 124                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 125                         ans[ai].length = UINT16_MAX;
 126                         ans[ai].rdata.ipv6_record = recs[ri].data.ipv6;
 127                         ai++;
 128                 }
 129                 break;
 130         case DNS_QTYPE_NS:
 131                 for (ri = 0; ri < el->num_values; ri++) {
 132                         if (recs[ri].wType != question->question_type) {
 133                                 continue;
 134                         }
 135
 136                         ZERO_STRUCT(ans[ai]);
 137                         ans[ai].name = question->name;
 138                         ans[ai].rr_type = DNS_QTYPE_NS;
 139                         ans[ai].rr_class = DNS_QCLASS_IN;
 140                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 141                         ans[ai].length = UINT16_MAX;
 142                         ans[ai].rdata.ns_record = recs[ri].data.ns;
 143                         ai++;
 144                 }
 145                 break;
 146         case DNS_QTYPE_SRV:
 147                 for (ri = 0; ri < el->num_values; ri++) {
 148                         if (recs[ri].wType != question->question_type) {
 149                                 continue;
 150                         }
 151
 152                         ZERO_STRUCT(ans[ai]);
 153                         ans[ai].name = question->name;
 154                         ans[ai].rr_type = DNS_QTYPE_SRV;
 155                         ans[ai].rr_class = DNS_QCLASS_IN;
 156                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 157                         ans[ai].length = UINT16_MAX;
 158                         ans[ai].rdata.srv_record.priority = recs[ri].data.srv.wPriority;
 159                         ans[ai].rdata.srv_record.weight = recs[ri].data.srv.wWeight;
 160                         ans[ai].rdata.srv_record.port = recs[ri].data.srv.wPort;
 161                         ans[ai].rdata.srv_record.target = recs[ri].data.srv.nameTarget;
 162                         ai++;
 163                 }
 164                 break;
 165         case DNS_QTYPE_SOA:
 166                 for (ri = 0; ri < el->num_values; ri++) {
 167                         if (recs[ri].wType != question->question_type) {
 168                                 continue;
 169                         }
 170
 171                         ZERO_STRUCT(ans[ai]);
 172                         ans[ai].name = question->name;
 173                         ans[ai].rr_type = DNS_QTYPE_SOA;
 174                         ans[ai].rr_class = DNS_QCLASS_IN;
 175                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 176                         ans[ai].length = UINT16_MAX;
 177                         ans[ai].rdata.soa_record.mname  = recs[ri].data.soa.mname;
 178                         ans[ai].rdata.soa_record.rname  = recs[ri].data.soa.rname;
 179                         ans[ai].rdata.soa_record.serial = recs[ri].data.soa.serial;
 180                         ans[ai].rdata.soa_record.refresh= recs[ri].data.soa.refresh;
 181                         ans[ai].rdata.soa_record.retry  = recs[ri].data.soa.retry;
 182                         ans[ai].rdata.soa_record.expire = recs[ri].data.soa.expire;
 183                         ans[ai].rdata.soa_record.minimum= recs[ri].data.soa.minimum;
 184                         ai++;
 185                 }
 186                 break;
 187         default:
 188                 return DNS_ERR(NOT_IMPLEMENTED);
 189         }
 190
 191         if (*ancount == ai) {
 192                 return DNS_ERR(NAME_ERROR);
 193         }
 194
 195         *ancount = ai;
 196         *answers = ans;
 197
 198         return WERR_OK;
 199
 200 }
 201
 202 WERROR dns_server_process_query(struct dns_server *dns,
 203                                 TALLOC_CTX *mem_ctx,
 204                                 struct dns_name_packet *in,
 205                                 struct dns_res_rec **answers,    uint16_t *ancount,
 206                                 struct dns_res_rec **nsrecs,     uint16_t *nscount,
 207                                 struct dns_res_rec **additional, uint16_t *arcount)
 208 {
 209         uint16_t i, num_answers=0;
 210         struct dns_res_rec *ans=NULL;
 211         WERROR werror;
 212
 213         ans = talloc_array(mem_ctx, struct dns_res_rec, 0);
 214         W_ERROR_HAVE_NO_MEMORY(ans);
 215
 216         for (i = 0; i < in->qdcount; ++i) {
 217                 werror = handle_question(dns, mem_ctx, &in->questions[i], &ans, &num_answers);
 218                 W_ERROR_NOT_OK_RETURN(werror);
 219         }
 220
 221         *answers = ans;
 222         *ancount = num_answers;
 223
 224         /*FIXME: Do something for these */
 225         *nsrecs  = NULL;
 226         *nscount = 0;
 227
 228         *additional = NULL;
 229         *arcount    = 0;
 230
 231         return WERR_OK;
 232 }