source: vendor/3.5.8/source4/nbt_server/query.c

/* 
   Unix SMB/CIFS implementation.

   answer name queries

   Copyright (C) Andrew Tridgell        2005
   
   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 "../lib/util/dlinklist.h"
#include "system/network.h"
#include "nbt_server/nbt_server.h"
#include "nbt_server/wins/winsserver.h"
#include "smbd/service_task.h"
#include "librpc/gen_ndr/ndr_nbt.h"
#include "lib/socket/socket.h"
#include "param/param.h"

/*
  answer a name query
*/
void nbtd_request_query(struct nbt_name_socket *nbtsock, 
                        struct nbt_name_packet *packet, 
                        struct socket_address *src)
{
        struct nbtd_iface_name *iname;
        struct nbt_name *name;
        struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
                                                       struct nbtd_interface);

        /* see if its a node status query */
        if (packet->qdcount == 1 &&
            packet->questions[0].question_type == NBT_QTYPE_STATUS) {
                nbtd_query_status(nbtsock, packet, src);
                return;
        }

        NBTD_ASSERT_PACKET(packet, src, packet->qdcount == 1);
        NBTD_ASSERT_PACKET(packet, src, 
                           packet->questions[0].question_type == NBT_QTYPE_NETBIOS);
        NBTD_ASSERT_PACKET(packet, src, 
                           packet->questions[0].question_class == NBT_QCLASS_IP);

        /* see if we have the requested name on this interface */
        name = &packet->questions[0].name;

        iname = nbtd_find_iname(iface, name, 0);
        if (iname == NULL) {
                /* don't send negative replies to broadcast queries */
                if (packet->operation & NBT_FLAG_BROADCAST) {
                        return;
                }

                if (packet->operation & NBT_FLAG_RECURSION_DESIRED) {
                        nbtd_winsserver_request(nbtsock, packet, src);
                        return;
                }

                /* otherwise send a negative reply */
                nbtd_negative_name_query_reply(nbtsock, packet, src);
                return;
        }

        /*
         * normally we should forward all queries with the
         * recursion desired flag to the wins server, but this
         * breaks are winsclient code, when doing mhomed registrations
         */
        if (!(packet->operation & NBT_FLAG_BROADCAST) &&
           (packet->operation & NBT_FLAG_RECURSION_DESIRED) &&
           (iname->nb_flags & NBT_NM_GROUP) &&
           lp_wins_support(iface->nbtsrv->task->lp_ctx)) {
                nbtd_winsserver_request(nbtsock, packet, src);
                return;
        }

        /* if the name is not yet active and its a broadcast query then
           ignore it for now */
        if (!(iname->nb_flags & NBT_NM_ACTIVE) && 
            (packet->operation & NBT_FLAG_BROADCAST)) {
                DEBUG(7,("Query for %s from %s - name not active yet on %s\n",
                         nbt_name_string(packet, name), src->addr, iface->ip_address));
                return;
        }

        nbtd_name_query_reply(nbtsock, packet, src,
                              &iname->name, iname->ttl, iname->nb_flags, 
                              nbtd_address_list(iface, packet));
}