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         char *tmp;
  39         uint32_t i;
  40
  41         ZERO_STRUCT(ans[ai]);
  42
  43         switch (rec->wType) {
  44         case DNS_QTYPE_CNAME:
  45                 ans[ai].rdata.cname_record = talloc_strdup(ans, rec->data.cname);
  46                 break;
  47         case DNS_QTYPE_A:
  48                 ans[ai].rdata.ipv4_record = talloc_strdup(ans, rec->data.ipv4);
  49                 break;
  50         case DNS_QTYPE_AAAA:
  51                 ans[ai].rdata.ipv6_record = rec->data.ipv6;
  52                 break;
  53         case DNS_TYPE_NS:
  54                 ans[ai].rdata.ns_record = rec->data.ns;
  55                 break;
  56         case DNS_QTYPE_SRV:
  57                 ans[ai].rdata.srv_record.priority = rec->data.srv.wPriority;
  58                 ans[ai].rdata.srv_record.weight   = rec->data.srv.wWeight;
  59                 ans[ai].rdata.srv_record.port     = rec->data.srv.wPort;
  60                 ans[ai].rdata.srv_record.target   = rec->data.srv.nameTarget;
  61                 break;
  62         case DNS_QTYPE_SOA:
  63                 ans[ai].rdata.soa_record.mname   = rec->data.soa.mname;
  64                 ans[ai].rdata.soa_record.rname   = rec->data.soa.rname;
  65                 ans[ai].rdata.soa_record.serial  = rec->data.soa.serial;
  66                 ans[ai].rdata.soa_record.refresh = rec->data.soa.refresh;
  67                 ans[ai].rdata.soa_record.retry   = rec->data.soa.retry;
  68                 ans[ai].rdata.soa_record.expire  = rec->data.soa.expire;
  69                 ans[ai].rdata.soa_record.minimum = rec->data.soa.minimum;
  70                 break;
  71         case DNS_QTYPE_PTR:
  72                 ans[ai].rdata.ptr_record = talloc_strdup(ans, rec->data.ptr);
  73                 break;
  74         case DNS_QTYPE_TXT:
  75                 tmp = talloc_asprintf(ans, "\"%s\"", rec->data.txt.str[0]);
  76                 for (i=1; i<rec->data.txt.count; i++) {
  77                         tmp = talloc_asprintf_append(tmp, " \"%s\"",
  78                                                      rec->data.txt.str[i]);
  79                 }
  80                 ans[ai].rdata.txt_record.txt = tmp;
  81                 break;
  82         default:
  83                 DEBUG(0, ("Got unhandled type %u query.\n", rec->wType));
  84                 return DNS_ERR(NOT_IMPLEMENTED);
  85         }
  86
  87         ans[ai].name = talloc_strdup(ans, question->name);
  88         ans[ai].rr_type = rec->wType;
  89         ans[ai].rr_class = DNS_QCLASS_IN;
  90         ans[ai].ttl = rec->dwTtlSeconds;
  91         ans[ai].length = UINT16_MAX;
  92         ai++;
  93
  94         *answers = ans;
  95         *ancount = ai;
  96
  97         return WERR_OK;
  98 }
  99
 100 static WERROR handle_question(struct dns_server *dns,
 101                               TALLOC_CTX *mem_ctx,
 102                               const struct dns_name_question *question,
 103                               struct dns_res_rec **answers, uint16_t *ancount)
 104 {
 105         struct dns_res_rec *ans;
 106         WERROR werror;
 107         unsigned int ri;
 108         struct dnsp_DnssrvRpcRecord *recs;
 109         uint16_t rec_count, ai = 0;
 110         struct ldb_dn *dn = NULL;
 111
 112         werror = dns_name2dn(dns, mem_ctx, question->name, &dn);
 113         W_ERROR_NOT_OK_RETURN(werror);
 114
 115         werror = dns_lookup_records(dns, mem_ctx, dn, &recs, &rec_count);
 116         W_ERROR_NOT_OK_RETURN(werror);
 117
 118         ans = talloc_zero_array(mem_ctx, struct dns_res_rec, rec_count);
 119         W_ERROR_HAVE_NO_MEMORY(ans);
 120
 121         for (ri = 0; ri < rec_count; ri++) {
 122                 if ((question->question_type != DNS_QTYPE_ALL) &&
 123                     (recs[ri].wType != question->question_type)) {
 124                         continue;
 125                 }
 126                 werror = create_response_rr(question, &recs[ri], &ans, &ai);
 127                 W_ERROR_NOT_OK_RETURN(werror);
 128         }
 129
 130         if (ai == 0) {
 131                 return DNS_ERR(NAME_ERROR);
 132         }
 133
 134         *ancount = ai;
 135         *answers = ans;
 136
 137         return WERR_OK;
 138
 139 }
 140
 141 WERROR dns_server_process_query(struct dns_server *dns,
 142                                 TALLOC_CTX *mem_ctx,
 143                                 struct dns_name_packet *in,
 144                                 struct dns_res_rec **answers,    uint16_t *ancount,
 145                                 struct dns_res_rec **nsrecs,     uint16_t *nscount,
 146                                 struct dns_res_rec **additional, uint16_t *arcount)
 147 {
 148         uint16_t num_answers=0;
 149         struct dns_res_rec *ans=NULL;
 150         WERROR werror;
 151
 152         if (in->qdcount != 1) {
 153                 return DNS_ERR(FORMAT_ERROR);
 154         }
 155
 156         /* Windows returns NOT_IMPLEMENTED on this as well */
 157         if (in->questions[0].question_class == DNS_QCLASS_NONE) {
 158                 return DNS_ERR(NOT_IMPLEMENTED);
 159         }
 160
 161         werror = handle_question(dns, mem_ctx, &in->questions[0], &ans, &num_answers);
 162         W_ERROR_NOT_OK_GOTO(werror, query_failed);
 163
 164         *answers = ans;
 165         *ancount = num_answers;
 166
 167         /*FIXME: Do something for these */
 168         *nsrecs  = NULL;
 169         *nscount = 0;
 170
 171         *additional = NULL;
 172         *arcount    = 0;
 173
 174         return WERR_OK;
 175
 176 query_failed:
 177         /*FIXME: add our SOA record to nsrecs */
 178         return werror;
 179 }