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 create_response_rr(const struct dns_name_question *question,
  33                                  const struct dnsp_DnssrvRpcRecord *rec,
  34                                  struct dns_res_rec **answers, uint16_t *ancount)
  35 {
  36         struct dns_res_rec *ans = *answers;
  37         uint16_t ai = *ancount;
  38
  39         ZERO_STRUCT(ans[ai]);
  40
  41         switch (rec->wType) {
  42         case DNS_QTYPE_CNAME:
  43                 ans[ai].rdata.cname_record = talloc_strdup(ans, rec->data.cname);
  44                 break;
  45         case DNS_QTYPE_A:
  46                 ans[ai].rdata.ipv4_record = talloc_strdup(ans, rec->data.ipv4);
  47                 break;
  48         case DNS_QTYPE_AAAA:
  49                 ans[ai].rdata.ipv6_record = rec->data.ipv6;
  50                 break;
  51         case DNS_TYPE_NS:
  52                 ans[ai].rdata.ns_record = rec->data.ns;
  53                 break;
  54         case DNS_QTYPE_SRV:
  55                 ans[ai].rdata.srv_record.priority = rec->data.srv.wPriority;
  56                 ans[ai].rdata.srv_record.weight   = rec->data.srv.wWeight;
  57                 ans[ai].rdata.srv_record.port     = rec->data.srv.wPort;
  58                 ans[ai].rdata.srv_record.target   = rec->data.srv.nameTarget;
  59                 break;
  60         case DNS_QTYPE_SOA:
  61                 ans[ai].rdata.soa_record.mname   = rec->data.soa.mname;
  62                 ans[ai].rdata.soa_record.rname   = rec->data.soa.rname;
  63                 ans[ai].rdata.soa_record.serial  = rec->data.soa.serial;
  64                 ans[ai].rdata.soa_record.refresh = rec->data.soa.refresh;
  65                 ans[ai].rdata.soa_record.retry   = rec->data.soa.retry;
  66                 ans[ai].rdata.soa_record.expire  = rec->data.soa.expire;
  67                 ans[ai].rdata.soa_record.minimum = rec->data.soa.minimum;
  68                 break;
  69         default:
  70                 return DNS_ERR(NOT_IMPLEMENTED);
  71         }
  72
  73         ans[ai].name = talloc_strdup(ans, question->name);
  74         ans[ai].rr_type = rec->wType;
  75         ans[ai].rr_class = DNS_QCLASS_IN;
  76         ans[ai].ttl = rec->dwTtlSeconds;
  77         ans[ai].length = UINT16_MAX;
  78         ai++;
  79
  80         *answers = ans;
  81         *ancount = ai;
  82
  83         return WERR_OK;
  84 }
  85
  86 static WERROR handle_question(struct dns_server *dns,
  87                               TALLOC_CTX *mem_ctx,
  88                               const struct dns_name_question *question,
  89                               struct dns_res_rec **answers, uint16_t *ancount)
  90 {
  91         struct dns_res_rec *ans;
  92         struct ldb_dn *dn = NULL;
  93         WERROR werror;
  94         static const char * const attrs[] = { "dnsRecord", NULL};
  95         int ret;
  96         uint16_t ai = *ancount;
  97         unsigned int ri;
  98         struct ldb_message *msg = NULL;
  99         struct dnsp_DnssrvRpcRecord *recs;
 100         struct ldb_message_element *el;
 101
 102         werror = dns_name2dn(dns, mem_ctx, question->name, &dn);
 103         W_ERROR_NOT_OK_RETURN(werror);
 104
 105         ret = dsdb_search_one(dns->samdb, mem_ctx, &msg, dn,
 106                               LDB_SCOPE_BASE, attrs, 0, "%s", "(objectClass=dnsNode)");
 107         if (ret != LDB_SUCCESS) {
 108                 return DNS_ERR(NAME_ERROR);
 109         }
 110
 111         el = ldb_msg_find_element(msg, attrs[0]);
 112         if (el == NULL) {
 113                 return DNS_ERR(NAME_ERROR);
 114         }
 115
 116         recs = talloc_array(mem_ctx, struct dnsp_DnssrvRpcRecord, el->num_values);
 117         for (ri = 0; ri < el->num_values; ri++) {
 118                 struct ldb_val *v = &el->values[ri];
 119                 enum ndr_err_code ndr_err;
 120
 121                 ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
 122                                 (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
 123                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 124                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 125                         return DNS_ERR(SERVER_FAILURE);
 126                 }
 127         }
 128
 129         ans = talloc_realloc(mem_ctx, *answers, struct dns_res_rec,
 130                              ai + el->num_values);
 131         W_ERROR_HAVE_NO_MEMORY(ans);
 132
 133         for (ri = 0; ri < el->num_values; ri++) {
 134                 if ((question->question_type != DNS_QTYPE_ALL) &&
 135                     (recs[ri].wType != question->question_type)) {
 136                         continue;
 137                 }
 138                 create_response_rr(question, &recs[ri], &ans, &ai);
 139         }
 140
 141         if (*ancount == ai) {
 142                 return DNS_ERR(NAME_ERROR);
 143         }
 144
 145         *ancount = ai;
 146         *answers = ans;
 147
 148         return WERR_OK;
 149
 150 }
 151
 152 WERROR dns_server_process_query(struct dns_server *dns,
 153                                 TALLOC_CTX *mem_ctx,
 154                                 struct dns_name_packet *in,
 155                                 struct dns_res_rec **answers,    uint16_t *ancount,
 156                                 struct dns_res_rec **nsrecs,     uint16_t *nscount,
 157                                 struct dns_res_rec **additional, uint16_t *arcount)
 158 {
 159         uint16_t num_answers=0;
 160         struct dns_res_rec *ans=NULL;
 161         WERROR werror;
 162
 163         if (in->qdcount != 1) {
 164                 return DNS_ERR(FORMAT_ERROR);
 165         }
 166
 167         ans = talloc_array(mem_ctx, struct dns_res_rec, 0);
 168         W_ERROR_HAVE_NO_MEMORY(ans);
 169
 170         werror = handle_question(dns, mem_ctx, &in->questions[0], &ans, &num_answers);
 171         W_ERROR_NOT_OK_GOTO(werror, query_failed);
 172
 173         *answers = ans;
 174         *ancount = num_answers;
 175
 176         /*FIXME: Do something for these */
 177         *nsrecs  = NULL;
 178         *nscount = 0;
 179
 180         *additional = NULL;
 181         *arcount    = 0;
 182
 183         return WERR_OK;
 184
 185 query_failed:
 186         /*FIXME: add our SOA record to nsrecs */
 187         return werror;
 188 }