source: trunk/server/source4/dns_server/dns_update.c

/*
   Unix SMB/CIFS implementation.

   DNS server handler for update requests

   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/ntstatus.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 check_prerequsites(struct dns_server *dns,
                                 TALLOC_CTX *mem_ctx,
                                 const struct dns_name_packet *in,
                                 const struct dns_res_rec *prereqs, uint16_t count)
{
        const struct dns_name_question *zone;
        size_t host_part_len = 0;
        uint16_t i;

        zone = in->questions;

        for (i = 0; i < count; i++) {
                const struct dns_res_rec *r = &prereqs[i];
                bool match;

                if (r->ttl != 0) {
                        return DNS_ERR(FORMAT_ERROR);
                }
                match = dns_name_match(zone->name, r->name, &host_part_len);
                if (!match) {
                        /* TODO: check if we need to echo all prereqs if the
                         * first fails */
                        return DNS_ERR(NOTZONE);
                }
                if (r->rr_class == DNS_QCLASS_ANY) {
                        if (r->length != 0) {
                                return DNS_ERR(FORMAT_ERROR);
                        }
                        if (r->rr_type == DNS_QTYPE_ALL) {
                                /* TODO: Check if zone has at least one RR */
                                return DNS_ERR(NAME_ERROR);
                        } else {
                                /* TODO: Check if RR exists of the specified type */
                                return DNS_ERR(NXRRSET);
                        }
                }
                if (r->rr_class == DNS_QCLASS_NONE) {
                        if (r->length != 0) {
                                return DNS_ERR(FORMAT_ERROR);
                        }
                        if (r->rr_type == DNS_QTYPE_ALL) {
                                /* TODO: Return this error if the given name exits in this zone */
                                return DNS_ERR(YXDOMAIN);
                        } else {
                                /* TODO: Return error if there's an RRset of this type in the zone */
                                return DNS_ERR(YXRRSET);
                        }
                }
                if (r->rr_class == zone->question_class) {
                        /* Check if there's a RR with this */
                        return DNS_ERR(NOT_IMPLEMENTED);
                } else {
                        return DNS_ERR(FORMAT_ERROR);
                }
        }


        return WERR_OK;
}

static WERROR update_prescan(const struct dns_name_question *zone,
                             const struct dns_res_rec *updates, uint16_t count)
{
        const struct dns_res_rec *r;
        uint16_t i;
        size_t host_part_len;
        bool match;

        for (i = 0; i < count; i++) {
                r = &updates[i];
                match = dns_name_match(zone->name, r->name, &host_part_len);
                if (!match) {
                        return DNS_ERR(NOTZONE);
                }
                if (zone->question_class == r->rr_class) {
                        /*TODO: also check for AXFR,MAILA,MAILB  */
                        if (r->rr_type == DNS_QTYPE_ALL) {
                                return DNS_ERR(FORMAT_ERROR);
                        }
                } else if (r->rr_class == DNS_QCLASS_ANY) {
                        if (r->ttl != 0 || r->length != 0) {
                                return DNS_ERR(FORMAT_ERROR);
                        }
                } else if (r->rr_class == DNS_QCLASS_NONE) {
                        if (r->ttl != 0 || r->rr_type == DNS_QTYPE_ALL) {
                                return DNS_ERR(FORMAT_ERROR);
                        }
                } else {
                        return DNS_ERR(FORMAT_ERROR);
                }
        }
        return WERR_OK;
}

WERROR dns_server_process_update(struct dns_server *dns,
                                 TALLOC_CTX *mem_ctx,
                                 struct dns_name_packet *in,
                                 const struct dns_res_rec *prereqs, uint16_t prereq_count,
                                 struct dns_res_rec **updates,      uint16_t *update_count,
                                 struct dns_res_rec **additional,   uint16_t *arcount)
{
        struct dns_name_question *zone;
        const struct dns_server_zone *z;
        size_t host_part_len = 0;
        WERROR werror = DNS_ERR(NOT_IMPLEMENTED);
        bool update_allowed = false;

        if (in->qdcount != 1) {
                return DNS_ERR(FORMAT_ERROR);
        }

        zone = in->questions;

        if (zone->question_type != DNS_QTYPE_SOA) {
                return DNS_ERR(FORMAT_ERROR);
        }

        DEBUG(0, ("Got a dns update request.\n"));

        for (z = dns->zones; z != NULL; z = z->next) {
                bool match;

                match = dns_name_match(z->name, zone->name, &host_part_len);
                if (match) {
                        break;
                }
        }

        if (z == NULL) {
                return DNS_ERR(NOTAUTH);
        }

        if (host_part_len != 0) {
                /* TODO: We need to delegate this one */
                return DNS_ERR(NOT_IMPLEMENTED);
        }

        werror = check_prerequsites(dns, mem_ctx, in, prereqs, prereq_count);
        W_ERROR_NOT_OK_RETURN(werror);

        /* TODO: Check if update is allowed, we probably want "always",
         * key-based GSSAPI, key-based bind-style TSIG and "never" as
         * smb.conf options. */
        if (!update_allowed) {
                return DNS_ERR(REFUSED);
        }

        werror = update_prescan(in->questions, *updates, *update_count);
        W_ERROR_NOT_OK_RETURN(werror);

        return werror;
}