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
);
50 if (ans
[ai
].rdata
.cname_record
== NULL
) {
55 ans
[ai
].rdata
.ipv4_record
= talloc_strdup(ans
, rec
->data
.ipv4
);
56 if (ans
[ai
].rdata
.ipv4_record
== NULL
) {
61 ans
[ai
].rdata
.ipv6_record
= rec
->data
.ipv6
;
64 ans
[ai
].rdata
.ns_record
= rec
->data
.ns
;
67 ans
[ai
].rdata
.srv_record
.priority
= rec
->data
.srv
.wPriority
;
68 ans
[ai
].rdata
.srv_record
.weight
= rec
->data
.srv
.wWeight
;
69 ans
[ai
].rdata
.srv_record
.port
= rec
->data
.srv
.wPort
;
70 ans
[ai
].rdata
.srv_record
.target
= rec
->data
.srv
.nameTarget
;
73 ans
[ai
].rdata
.soa_record
.mname
= rec
->data
.soa
.mname
;
74 ans
[ai
].rdata
.soa_record
.rname
= rec
->data
.soa
.rname
;
75 ans
[ai
].rdata
.soa_record
.serial
= rec
->data
.soa
.serial
;
76 ans
[ai
].rdata
.soa_record
.refresh
= rec
->data
.soa
.refresh
;
77 ans
[ai
].rdata
.soa_record
.retry
= rec
->data
.soa
.retry
;
78 ans
[ai
].rdata
.soa_record
.expire
= rec
->data
.soa
.expire
;
79 ans
[ai
].rdata
.soa_record
.minimum
= rec
->data
.soa
.minimum
;
82 ans
[ai
].rdata
.ptr_record
= talloc_strdup(ans
, rec
->data
.ptr
);
85 tmp
= talloc_asprintf(ans
, "\"%s\"", rec
->data
.txt
.str
[0]);
89 for (i
=1; i
<rec
->data
.txt
.count
; i
++) {
90 tmp
= talloc_asprintf_append(tmp
, " \"%s\"",
91 rec
->data
.txt
.str
[i
]);
96 ans
[ai
].rdata
.txt_record
.txt
= tmp
;
99 DEBUG(0, ("Got unhandled type %u query.\n", rec
->wType
));
100 return DNS_ERR(NOT_IMPLEMENTED
);
103 ans
[ai
].name
= talloc_strdup(ans
, question
->name
);
104 if (ans
[ai
].name
== NULL
) {
107 ans
[ai
].rr_type
= rec
->wType
;
108 ans
[ai
].rr_class
= DNS_QCLASS_IN
;
109 ans
[ai
].ttl
= rec
->dwTtlSeconds
;
110 ans
[ai
].length
= UINT16_MAX
;
119 static WERROR
ask_forwarder(struct dns_server
*dns
,
121 struct dns_name_question
*question
,
122 struct dns_res_rec
**answers
, uint16_t *ancount
,
123 struct dns_res_rec
**nsrecs
, uint16_t *nscount
,
124 struct dns_res_rec
**additional
, uint16_t *arcount
)
126 struct tevent_context
*ev
= tevent_context_init(mem_ctx
);
127 struct dns_name_packet
*out_packet
, *in_packet
;
128 uint16_t id
= random();
130 enum ndr_err_code ndr_err
;
131 WERROR werr
= WERR_OK
;
132 struct tevent_req
*req
;
133 const char *forwarder
= lpcfg_dns_forwarder(dns
->task
->lp_ctx
);
135 if (!is_ipaddress(forwarder
)) {
136 DEBUG(0, ("Invalid 'dns forwarder' setting '%s', needs to be "
137 "an IP address\n", forwarder
));
138 return DNS_ERR(NAME_ERROR
);
141 out_packet
= talloc_zero(mem_ctx
, struct dns_name_packet
);
142 W_ERROR_HAVE_NO_MEMORY(out_packet
);
145 out_packet
->operation
|= DNS_OPCODE_QUERY
| DNS_FLAG_RECURSION_DESIRED
;
147 out_packet
->qdcount
= 1;
148 out_packet
->questions
= question
;
150 ndr_err
= ndr_push_struct_blob(&out
, mem_ctx
, out_packet
,
151 (ndr_push_flags_fn_t
)ndr_push_dns_name_packet
);
152 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err
)) {
153 return DNS_ERR(SERVER_FAILURE
);
156 req
= dns_udp_request_send(mem_ctx
, ev
, forwarder
, out
.data
, out
.length
);
157 W_ERROR_HAVE_NO_MEMORY(req
);
159 if(!tevent_req_poll(req
, ev
)) {
160 return DNS_ERR(SERVER_FAILURE
);
163 werr
= dns_udp_request_recv(req
, mem_ctx
, &in
.data
, &in
.length
);
164 W_ERROR_NOT_OK_RETURN(werr
);
166 in_packet
= talloc_zero(mem_ctx
, struct dns_name_packet
);
167 W_ERROR_HAVE_NO_MEMORY(in_packet
);
169 ndr_err
= ndr_pull_struct_blob(&in
, in_packet
, in_packet
,
170 (ndr_pull_flags_fn_t
)ndr_pull_dns_name_packet
);
171 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err
)) {
172 return DNS_ERR(SERVER_FAILURE
);
175 if (in_packet
->id
!= id
) {
176 DEBUG(0, ("DNS packet id mismatch: 0x%0x, expected 0x%0x\n",
178 return DNS_ERR(NAME_ERROR
);
181 *ancount
= in_packet
->ancount
;
182 *answers
= talloc_move(mem_ctx
, &in_packet
->answers
);
184 *nscount
= in_packet
->nscount
;
185 *nsrecs
= talloc_move(mem_ctx
, &in_packet
->nsrecs
);
187 *arcount
= in_packet
->arcount
;
188 *additional
= talloc_move(mem_ctx
, &in_packet
->additional
);
193 static WERROR
handle_question(struct dns_server
*dns
,
195 const struct dns_name_question
*question
,
196 struct dns_res_rec
**answers
, uint16_t *ancount
)
198 struct dns_res_rec
*ans
;
201 struct dnsp_DnssrvRpcRecord
*recs
;
202 uint16_t rec_count
, ai
= 0;
203 struct ldb_dn
*dn
= NULL
;
205 werror
= dns_name2dn(dns
, mem_ctx
, question
->name
, &dn
);
206 W_ERROR_NOT_OK_RETURN(werror
);
208 werror
= dns_lookup_records(dns
, mem_ctx
, dn
, &recs
, &rec_count
);
209 W_ERROR_NOT_OK_RETURN(werror
);
211 ans
= talloc_zero_array(mem_ctx
, struct dns_res_rec
, rec_count
);
212 W_ERROR_HAVE_NO_MEMORY(ans
);
214 for (ri
= 0; ri
< rec_count
; ri
++) {
215 if ((question
->question_type
!= DNS_QTYPE_ALL
) &&
216 (recs
[ri
].wType
!= question
->question_type
)) {
219 werror
= create_response_rr(question
, &recs
[ri
], &ans
, &ai
);
220 W_ERROR_NOT_OK_RETURN(werror
);
224 return DNS_ERR(NAME_ERROR
);
234 WERROR
dns_server_process_query(struct dns_server
*dns
,
235 struct dns_request_state
*state
,
237 struct dns_name_packet
*in
,
238 struct dns_res_rec
**answers
, uint16_t *ancount
,
239 struct dns_res_rec
**nsrecs
, uint16_t *nscount
,
240 struct dns_res_rec
**additional
, uint16_t *arcount
)
242 uint16_t num_answers
=0, num_nsrecs
=0, num_additional
=0;
243 struct dns_res_rec
*ans
=NULL
, *ns
=NULL
, *adds
=NULL
;
246 if (in
->qdcount
!= 1) {
247 return DNS_ERR(FORMAT_ERROR
);
250 /* Windows returns NOT_IMPLEMENTED on this as well */
251 if (in
->questions
[0].question_class
== DNS_QCLASS_NONE
) {
252 return DNS_ERR(NOT_IMPLEMENTED
);
255 if (dns_authorative_for_zone(dns
, in
->questions
[0].name
)) {
256 state
->flags
|= DNS_FLAG_AUTHORITATIVE
;
257 werror
= handle_question(dns
, mem_ctx
, &in
->questions
[0],
260 if (state
->flags
& DNS_FLAG_RECURSION_DESIRED
&&
261 state
->flags
& DNS_FLAG_RECURSION_AVAIL
) {
262 DEBUG(2, ("Not authorative for '%s', forwarding\n",
263 in
->questions
[0].name
));
264 werror
= ask_forwarder(dns
, mem_ctx
, &in
->questions
[0],
267 &adds
, &num_additional
);
269 werror
= DNS_ERR(NAME_ERROR
);
272 W_ERROR_NOT_OK_GOTO(werror
, query_failed
);
275 *ancount
= num_answers
;
277 /*FIXME: Do something for these */
279 *nscount
= num_nsrecs
;
282 *arcount
= num_additional
;
287 /*FIXME: add our SOA record to nsrecs */