2 Unix SMB/CIFS implementation.
4 DNS server handler for queries
6 Copyright (C) 2010 Kai Blin <kai@samba.org>
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.
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.
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/>.
23 #include "smbd/service_task.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"
29 #include "param/param.h"
30 #include "dsdb/samdb/samdb.h"
31 #include "dsdb/common/util.h"
32 #include "dns_server/dns_server.h"
33 #include "libcli/dns/libdns.h"
34 #include "lib/util/util_net.h"
36 static WERROR
create_response_rr(const struct dns_name_question
*question
,
37 const struct dnsp_DnssrvRpcRecord
*rec
,
38 struct dns_res_rec
**answers
, uint16_t *ancount
)
40 struct dns_res_rec
*ans
= *answers
;
41 uint16_t ai
= *ancount
;
49 ans
[ai
].rdata
.cname_record
= talloc_strdup(ans
, rec
->data
.cname
);
52 ans
[ai
].rdata
.ipv4_record
= talloc_strdup(ans
, rec
->data
.ipv4
);
55 ans
[ai
].rdata
.ipv6_record
= rec
->data
.ipv6
;
58 ans
[ai
].rdata
.ns_record
= rec
->data
.ns
;
61 ans
[ai
].rdata
.srv_record
.priority
= rec
->data
.srv
.wPriority
;
62 ans
[ai
].rdata
.srv_record
.weight
= rec
->data
.srv
.wWeight
;
63 ans
[ai
].rdata
.srv_record
.port
= rec
->data
.srv
.wPort
;
64 ans
[ai
].rdata
.srv_record
.target
= rec
->data
.srv
.nameTarget
;
67 ans
[ai
].rdata
.soa_record
.mname
= rec
->data
.soa
.mname
;
68 ans
[ai
].rdata
.soa_record
.rname
= rec
->data
.soa
.rname
;
69 ans
[ai
].rdata
.soa_record
.serial
= rec
->data
.soa
.serial
;
70 ans
[ai
].rdata
.soa_record
.refresh
= rec
->data
.soa
.refresh
;
71 ans
[ai
].rdata
.soa_record
.retry
= rec
->data
.soa
.retry
;
72 ans
[ai
].rdata
.soa_record
.expire
= rec
->data
.soa
.expire
;
73 ans
[ai
].rdata
.soa_record
.minimum
= rec
->data
.soa
.minimum
;
76 ans
[ai
].rdata
.ptr_record
= talloc_strdup(ans
, rec
->data
.ptr
);
79 tmp
= talloc_asprintf(ans
, "\"%s\"", rec
->data
.txt
.str
[0]);
80 for (i
=1; i
<rec
->data
.txt
.count
; i
++) {
81 tmp
= talloc_asprintf_append(tmp
, " \"%s\"",
82 rec
->data
.txt
.str
[i
]);
84 ans
[ai
].rdata
.txt_record
.txt
= tmp
;
87 DEBUG(0, ("Got unhandled type %u query.\n", rec
->wType
));
88 return DNS_ERR(NOT_IMPLEMENTED
);
91 ans
[ai
].name
= talloc_strdup(ans
, question
->name
);
92 ans
[ai
].rr_type
= rec
->wType
;
93 ans
[ai
].rr_class
= DNS_QCLASS_IN
;
94 ans
[ai
].ttl
= rec
->dwTtlSeconds
;
95 ans
[ai
].length
= UINT16_MAX
;
104 static WERROR
ask_forwarder(struct dns_server
*dns
,
106 struct dns_name_question
*question
,
107 struct dns_res_rec
**answers
, uint16_t *ancount
,
108 struct dns_res_rec
**nsrecs
, uint16_t *nscount
,
109 struct dns_res_rec
**additional
, uint16_t *arcount
)
111 struct tevent_context
*ev
= tevent_context_init(mem_ctx
);
112 struct dns_name_packet
*out_packet
, *in_packet
;
113 uint16_t id
= random();
115 enum ndr_err_code ndr_err
;
116 WERROR werr
= WERR_OK
;
117 struct tevent_req
*req
;
118 const char *forwarder
= lpcfg_dns_forwarder(dns
->task
->lp_ctx
);
120 if (!is_ipaddress(forwarder
)) {
121 DEBUG(0, ("Invalid 'dns forwarder' setting '%s', needs to be "
122 "an IP address\n", forwarder
));
123 return DNS_ERR(NAME_ERROR
);
126 out_packet
= talloc_zero(mem_ctx
, struct dns_name_packet
);
127 W_ERROR_HAVE_NO_MEMORY(out_packet
);
130 out_packet
->operation
|= DNS_OPCODE_QUERY
| DNS_FLAG_RECURSION_DESIRED
;
132 out_packet
->qdcount
= 1;
133 out_packet
->questions
= question
;
135 ndr_err
= ndr_push_struct_blob(&out
, mem_ctx
, out_packet
,
136 (ndr_push_flags_fn_t
)ndr_push_dns_name_packet
);
137 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err
)) {
138 return DNS_ERR(SERVER_FAILURE
);
141 req
= dns_udp_request_send(mem_ctx
, ev
, forwarder
, out
.data
, out
.length
);
142 W_ERROR_HAVE_NO_MEMORY(req
);
144 if(!tevent_req_poll(req
, ev
)) {
145 return DNS_ERR(SERVER_FAILURE
);
148 werr
= dns_udp_request_recv(req
, mem_ctx
, &in
.data
, &in
.length
);
149 W_ERROR_NOT_OK_RETURN(werr
);
151 in_packet
= talloc_zero(mem_ctx
, struct dns_name_packet
);
152 W_ERROR_HAVE_NO_MEMORY(in_packet
);
154 ndr_err
= ndr_pull_struct_blob(&in
, in_packet
, in_packet
,
155 (ndr_pull_flags_fn_t
)ndr_pull_dns_name_packet
);
156 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err
)) {
157 return DNS_ERR(SERVER_FAILURE
);
160 if (in_packet
->id
!= id
) {
161 DEBUG(0, ("DNS packet id mismatch: 0x%0x, expected 0x%0x\n",
163 return DNS_ERR(NAME_ERROR
);
166 *ancount
= in_packet
->ancount
;
167 *answers
= talloc_move(mem_ctx
, &in_packet
->answers
);
169 *nscount
= in_packet
->nscount
;
170 *nsrecs
= talloc_move(mem_ctx
, &in_packet
->nsrecs
);
172 *arcount
= in_packet
->arcount
;
173 *additional
= talloc_move(mem_ctx
, &in_packet
->additional
);
178 static WERROR
handle_question(struct dns_server
*dns
,
180 const struct dns_name_question
*question
,
181 struct dns_res_rec
**answers
, uint16_t *ancount
)
183 struct dns_res_rec
*ans
;
186 struct dnsp_DnssrvRpcRecord
*recs
;
187 uint16_t rec_count
, ai
= 0;
188 struct ldb_dn
*dn
= NULL
;
190 werror
= dns_name2dn(dns
, mem_ctx
, question
->name
, &dn
);
191 W_ERROR_NOT_OK_RETURN(werror
);
193 werror
= dns_lookup_records(dns
, mem_ctx
, dn
, &recs
, &rec_count
);
194 W_ERROR_NOT_OK_RETURN(werror
);
196 ans
= talloc_zero_array(mem_ctx
, struct dns_res_rec
, rec_count
);
197 W_ERROR_HAVE_NO_MEMORY(ans
);
199 for (ri
= 0; ri
< rec_count
; ri
++) {
200 if ((question
->question_type
!= DNS_QTYPE_ALL
) &&
201 (recs
[ri
].wType
!= question
->question_type
)) {
204 werror
= create_response_rr(question
, &recs
[ri
], &ans
, &ai
);
205 W_ERROR_NOT_OK_RETURN(werror
);
209 return DNS_ERR(NAME_ERROR
);
219 WERROR
dns_server_process_query(struct dns_server
*dns
,
220 struct dns_request_state
*state
,
222 struct dns_name_packet
*in
,
223 struct dns_res_rec
**answers
, uint16_t *ancount
,
224 struct dns_res_rec
**nsrecs
, uint16_t *nscount
,
225 struct dns_res_rec
**additional
, uint16_t *arcount
)
227 uint16_t num_answers
=0, num_nsrecs
=0, num_additional
=0;
228 struct dns_res_rec
*ans
=NULL
, *ns
=NULL
, *adds
=NULL
;
231 if (in
->qdcount
!= 1) {
232 return DNS_ERR(FORMAT_ERROR
);
235 /* Windows returns NOT_IMPLEMENTED on this as well */
236 if (in
->questions
[0].question_class
== DNS_QCLASS_NONE
) {
237 return DNS_ERR(NOT_IMPLEMENTED
);
240 if (dns_authorative_for_zone(dns
, in
->questions
[0].name
)) {
241 state
->flags
|= DNS_FLAG_AUTHORITATIVE
;
242 werror
= handle_question(dns
, mem_ctx
, &in
->questions
[0],
245 if (state
->flags
& DNS_FLAG_RECURSION_DESIRED
&&
246 state
->flags
& DNS_FLAG_RECURSION_AVAIL
) {
247 DEBUG(2, ("Not authorative for '%s', forwarding\n",
248 in
->questions
[0].name
));
249 werror
= ask_forwarder(dns
, mem_ctx
, &in
->questions
[0],
252 &adds
, &num_additional
);
254 werror
= DNS_ERR(NAME_ERROR
);
257 W_ERROR_NOT_OK_GOTO(werror
, query_failed
);
260 *ancount
= num_answers
;
262 /*FIXME: Do something for these */
264 *nscount
= num_nsrecs
;
267 *arcount
= num_additional
;
272 /*FIXME: add our SOA record to nsrecs */