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/*
Unix SMB/CIFS implementation.
DNS server handler for queries
Copyright (C) 2010 Kai Blin <kai@samba.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "libcli/util/werror.h"
#include "librpc/ndr/libndr.h"
#include "librpc/gen_ndr/ndr_dns.h"
#include "librpc/gen_ndr/ndr_dnsp.h"
#include <ldb.h>
#include "dsdb/samdb/samdb.h"
#include "dsdb/common/util.h"
#include "dns_server/dns_server.h"
static WERROR create_response_rr(const struct dns_name_question *question,
const struct dnsp_DnssrvRpcRecord *rec,
struct dns_res_rec **answers, uint16_t *ancount)
{
struct dns_res_rec *ans = *answers;
uint16_t ai = *ancount;
ZERO_STRUCT(ans[ai]);
switch (rec->wType) {
case DNS_QTYPE_CNAME:
ans[ai].rdata.cname_record = talloc_strdup(ans, rec->data.cname);
break;
case DNS_QTYPE_A:
ans[ai].rdata.ipv4_record = talloc_strdup(ans, rec->data.ipv4);
break;
case DNS_QTYPE_AAAA:
ans[ai].rdata.ipv6_record = rec->data.ipv6;
break;
case DNS_TYPE_NS:
ans[ai].rdata.ns_record = rec->data.ns;
break;
case DNS_QTYPE_SRV:
ans[ai].rdata.srv_record.priority = rec->data.srv.wPriority;
ans[ai].rdata.srv_record.weight = rec->data.srv.wWeight;
ans[ai].rdata.srv_record.port = rec->data.srv.wPort;
ans[ai].rdata.srv_record.target = rec->data.srv.nameTarget;
break;
case DNS_QTYPE_SOA:
ans[ai].rdata.soa_record.mname = rec->data.soa.mname;
ans[ai].rdata.soa_record.rname = rec->data.soa.rname;
ans[ai].rdata.soa_record.serial = rec->data.soa.serial;
ans[ai].rdata.soa_record.refresh = rec->data.soa.refresh;
ans[ai].rdata.soa_record.retry = rec->data.soa.retry;
ans[ai].rdata.soa_record.expire = rec->data.soa.expire;
ans[ai].rdata.soa_record.minimum = rec->data.soa.minimum;
break;
default:
return DNS_ERR(NOT_IMPLEMENTED);
}
ans[ai].name = talloc_strdup(ans, question->name);
ans[ai].rr_type = rec->wType;
ans[ai].rr_class = DNS_QCLASS_IN;
ans[ai].ttl = rec->dwTtlSeconds;
ans[ai].length = UINT16_MAX;
ai++;
*answers = ans;
*ancount = ai;
return WERR_OK;
}
static WERROR handle_question(struct dns_server *dns,
TALLOC_CTX *mem_ctx,
const struct dns_name_question *question,
struct dns_res_rec **answers, uint16_t *ancount)
{
struct dns_res_rec *ans;
struct ldb_dn *dn = NULL;
WERROR werror;
static const char * const attrs[] = { "dnsRecord", NULL};
int ret;
uint16_t ai = *ancount;
unsigned int ri;
struct ldb_message *msg = NULL;
struct dnsp_DnssrvRpcRecord *recs;
struct ldb_message_element *el;
werror = dns_name2dn(dns, mem_ctx, question->name, &dn);
W_ERROR_NOT_OK_RETURN(werror);
ret = dsdb_search_one(dns->samdb, mem_ctx, &msg, dn,
LDB_SCOPE_BASE, attrs, 0, "%s", "(objectClass=dnsNode)");
if (ret != LDB_SUCCESS) {
return DNS_ERR(NAME_ERROR);
}
el = ldb_msg_find_element(msg, attrs[0]);
if (el == NULL) {
return DNS_ERR(NAME_ERROR);
}
recs = talloc_array(mem_ctx, struct dnsp_DnssrvRpcRecord, el->num_values);
for (ri = 0; ri < el->num_values; ri++) {
struct ldb_val *v = &el->values[ri];
enum ndr_err_code ndr_err;
ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
(ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
return DNS_ERR(SERVER_FAILURE);
}
}
ans = talloc_realloc(mem_ctx, *answers, struct dns_res_rec,
ai + el->num_values);
W_ERROR_HAVE_NO_MEMORY(ans);
for (ri = 0; ri < el->num_values; ri++) {
if ((question->question_type != DNS_QTYPE_ALL) &&
(recs[ri].wType != question->question_type)) {
continue;
}
create_response_rr(question, &recs[ri], &ans, &ai);
}
if (*ancount == ai) {
return DNS_ERR(NAME_ERROR);
}
*ancount = ai;
*answers = ans;
return WERR_OK;
}
WERROR dns_server_process_query(struct dns_server *dns,
TALLOC_CTX *mem_ctx,
struct dns_name_packet *in,
struct dns_res_rec **answers, uint16_t *ancount,
struct dns_res_rec **nsrecs, uint16_t *nscount,
struct dns_res_rec **additional, uint16_t *arcount)
{
uint16_t num_answers=0;
struct dns_res_rec *ans=NULL;
WERROR werror;
if (in->qdcount != 1) {
return DNS_ERR(FORMAT_ERROR);
}
ans = talloc_array(mem_ctx, struct dns_res_rec, 0);
W_ERROR_HAVE_NO_MEMORY(ans);
werror = handle_question(dns, mem_ctx, &in->questions[0], &ans, &num_answers);
W_ERROR_NOT_OK_GOTO(werror, query_failed);
*answers = ans;
*ancount = num_answers;
/*FIXME: Do something for these */
*nsrecs = NULL;
*nscount = 0;
*additional = NULL;
*arcount = 0;
return WERR_OK;
query_failed:
/*FIXME: add our SOA record to nsrecs */
return werror;
}
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