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         WERROR werror;
  93         unsigned int ri;
  94         struct dnsp_DnssrvRpcRecord *recs;
  95         uint16_t rec_count, ai = 0;
  96         struct ldb_dn *dn = NULL;
  97
  98         werror = dns_name2dn(dns, mem_ctx, question->name, &dn);
  99         W_ERROR_NOT_OK_RETURN(werror);
 100
 101         werror = dns_lookup_records(dns, mem_ctx, dn, &recs, &rec_count);
 102         W_ERROR_NOT_OK_RETURN(werror);
 103
 104         ans = talloc_zero_array(mem_ctx, struct dns_res_rec, rec_count);
 105         W_ERROR_HAVE_NO_MEMORY(ans);
 106
 107         for (ri = 0; ri < rec_count; ri++) {
 108                 if ((question->question_type != DNS_QTYPE_ALL) &&
 109                     (recs[ri].wType != question->question_type)) {
 110                         continue;
 111                 }
 112                 create_response_rr(question, &recs[ri], &ans, &ai);
 113         }
 114
 115         if (ai == 0) {
 116                 return DNS_ERR(NAME_ERROR);
 117         }
 118
 119         *ancount = ai;
 120         *answers = ans;
 121
 122         return WERR_OK;
 123
 124 }
 125
 126 WERROR dns_server_process_query(struct dns_server *dns,
 127                                 TALLOC_CTX *mem_ctx,
 128                                 struct dns_name_packet *in,
 129                                 struct dns_res_rec **answers,    uint16_t *ancount,
 130                                 struct dns_res_rec **nsrecs,     uint16_t *nscount,
 131                                 struct dns_res_rec **additional, uint16_t *arcount)
 132 {
 133         uint16_t num_answers=0;
 134         struct dns_res_rec *ans=NULL;
 135         WERROR werror;
 136
 137         if (in->qdcount != 1) {
 138                 return DNS_ERR(FORMAT_ERROR);
 139         }
 140
 141         /* Windows returns NOT_IMPLEMENTED on this as well */
 142         if (in->questions[0].question_class == DNS_QCLASS_NONE) {
 143                 return DNS_ERR(NOT_IMPLEMENTED);
 144         }
 145
 146         werror = handle_question(dns, mem_ctx, &in->questions[0], &ans, &num_answers);
 147         W_ERROR_NOT_OK_GOTO(werror, query_failed);
 148
 149         *answers = ans;
 150         *ancount = num_answers;
 151
 152         /*FIXME: Do something for these */
 153         *nsrecs  = NULL;
 154         *nscount = 0;
 155
 156         *additional = NULL;
 157         *arcount    = 0;
 158
 159         return WERR_OK;
 160
 161 query_failed:
 162         /*FIXME: add our SOA record to nsrecs */
 163         return werror;
 164 }