nmbd/nmbd_become_dmb.c

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/* 
   Unix SMB/CIFS implementation.
   NBT netbios routines and daemon - version 2
   Copyright (C) Andrew Tridgell 1994-1998
   Copyright (C) Luke Kenneth Casson Leighton 1994-1998
   Copyright (C) Jeremy Allison 1994-2003
   
   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 2 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   
*/

#include "includes.h"

extern struct in_addr allones_ip;

extern uint16 samba_nb_type; /* Samba's NetBIOS type. */

static void become_domain_master_browser_bcast(const char *);

/****************************************************************************
  Fail to become a Domain Master Browser on a subnet.
  ****************************************************************************/

static void become_domain_master_fail(struct subnet_record *subrec,
                                      struct response_record *rrec,
                                      struct nmb_name *fail_name)
{
        unstring failname;
        struct work_record *work;
        struct server_record *servrec;

        pull_ascii_nstring(failname, sizeof(failname), fail_name->name);
        work = find_workgroup_on_subnet(subrec, failname);
        if(!work) {
                DEBUG(0,("become_domain_master_fail: Error - cannot find \
workgroup %s on subnet %s\n", failname, subrec->subnet_name));
                return;
        }

        /* Set the state back to DOMAIN_NONE. */
        work->dom_state = DOMAIN_NONE;

        if((servrec = find_server_in_workgroup( work, global_myname())) == NULL) {
                DEBUG(0,("become_domain_master_fail: Error - cannot find server %s \
in workgroup %s on subnet %s\n",
                        global_myname(), work->work_group, subrec->subnet_name));
                return;
        }

        /* Update our server status. */
        servrec->serv.type &= ~SV_TYPE_DOMAIN_MASTER;

        /* Tell the namelist writer to write out a change. */
        subrec->work_changed = True;

        DEBUG(0,("become_domain_master_fail: Failed to become a domain master browser for \
workgroup %s on subnet %s. Couldn't register name %s.\n",
                work->work_group, subrec->subnet_name, nmb_namestr(fail_name)));
}

/****************************************************************************
  Become a Domain Master Browser on a subnet.
  ****************************************************************************/

static void become_domain_master_stage2(struct subnet_record *subrec, 
                                        struct userdata_struct *userdata,
                                        struct nmb_name *registered_name,
                                        uint16 nb_flags,
                                        int ttl, struct in_addr registered_ip)
{
        unstring regname;
        struct work_record *work;
        struct server_record *servrec;

        pull_ascii_nstring(regname, sizeof(regname), registered_name->name);
        work = find_workgroup_on_subnet( subrec, regname);

        if(!work) {
                DEBUG(0,("become_domain_master_stage2: Error - cannot find \
workgroup %s on subnet %s\n", regname, subrec->subnet_name));
                return;
        }

        if((servrec = find_server_in_workgroup( work, global_myname())) == NULL) {
                DEBUG(0,("become_domain_master_stage2: Error - cannot find server %s \
in workgroup %s on subnet %s\n", 
                global_myname(), regname, subrec->subnet_name));
                work->dom_state = DOMAIN_NONE;
                return;
        }

        /* Set the state in the workgroup structure. */
        work->dom_state = DOMAIN_MST; /* Become domain master. */

        /* Update our server status. */
        servrec->serv.type |= (SV_TYPE_NT|SV_TYPE_DOMAIN_MASTER);

        /* Tell the namelist writer to write out a change. */
        subrec->work_changed = True;

        if( DEBUGLVL( 0 ) ) {
                dbgtext( "*****\n\nSamba server %s ", global_myname() );
                dbgtext( "is now a domain master browser for " );
                dbgtext( "workgroup %s ", work->work_group );
                dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
        }

        if( subrec == unicast_subnet ) {
                struct nmb_name nmbname;
                struct in_addr my_first_ip;
                struct in_addr *nip;

                /* Put our name and first IP address into the 
                   workgroup struct as domain master browser. This
                   will stop us syncing with ourself if we are also
                   a local master browser. */

                make_nmb_name(&nmbname, global_myname(), 0x20);

                work->dmb_name = nmbname;
                /* Pick the first interface ip address as the domain master browser ip. */
                nip = iface_n_ip(0);

                if (!nip) {
                        DEBUG(0,("become_domain_master_stage2: Error. iface_n_ip returned NULL\n"));
                        return;
                }

                my_first_ip = *nip;

                putip((char *)&work->dmb_addr, &my_first_ip);

                /* We successfully registered by unicast with the
                   WINS server.  We now expect to become the domain
                   master on the local subnets. If this fails, it's
                   probably a 1.9.16p2 to 1.9.16p11 server's fault.

                   This is a configuration issue that should be addressed
                   by the network administrator - you shouldn't have
                   several machines configured as a domain master browser
                   for the same WINS scope (except if they are 1.9.17 or
                   greater, and you know what you're doing.

                   see docs/DOMAIN.txt.

                */
                become_domain_master_browser_bcast(work->work_group);
        } else {
                /*
                 * Now we are a domain master on a broadcast subnet, we need to add
                 * the WORKGROUP<1b> name to the unicast subnet so that we can answer
                 * unicast requests sent to this name. This bug wasn't found for a while
                 * as it is strange to have a DMB without using WINS. JRA.
                 */
                insert_permanent_name_into_unicast(subrec, registered_name, nb_flags);
        }
}

/****************************************************************************
  Start the name registration process when becoming a Domain Master Browser
  on a subnet.
****************************************************************************/

static void become_domain_master_stage1(struct subnet_record *subrec, const char *wg_name)
{ 
        struct work_record *work;

        DEBUG(2,("become_domain_master_stage1: Becoming domain master browser for \
workgroup %s on subnet %s\n", wg_name, subrec->subnet_name));

        /* First, find the workgroup on the subnet. */
        if((work = find_workgroup_on_subnet( subrec, wg_name )) == NULL) {
                DEBUG(0,("become_domain_master_stage1: Error - unable to find workgroup %s on subnet %s.\n",
                        wg_name, subrec->subnet_name));
                return;
        }

        DEBUG(3,("become_domain_master_stage1: go to first stage: register <1b> name\n"));
        work->dom_state = DOMAIN_WAIT;

        /* WORKGROUP<1b> is the domain master browser name. */
        register_name(subrec, work->work_group,0x1b,samba_nb_type,
                        become_domain_master_stage2,
                        become_domain_master_fail, NULL);
}

/****************************************************************************
  Function called when a query for a WORKGROUP<1b> name succeeds.
  This is normally a fail condition as it means there is already
  a domain master browser for a workgroup and we were trying to
  become one.
****************************************************************************/

static void become_domain_master_query_success(struct subnet_record *subrec,
                        struct userdata_struct *userdata,
                        struct nmb_name *nmbname, struct in_addr ip, 
                        struct res_rec *rrec)
{
        unstring name;
        pull_ascii_nstring(name, sizeof(name), nmbname->name);

        /* If the given ip is not ours, then we can't become a domain
                controler as the name is already registered.
        */

        /* BUG note. Samba 1.9.16p11 servers seem to return the broadcast
                address or zero ip for this query. Pretend this is ok. */

        if(ismyip(ip) || ip_equal(allones_ip, ip) || is_zero_ip(ip)) {
                if( DEBUGLVL( 3 ) ) {
                        dbgtext( "become_domain_master_query_success():\n" );
                        dbgtext( "Our address (%s) ", inet_ntoa(ip) );
                        dbgtext( "returned in query for name %s ", nmb_namestr(nmbname) );
                        dbgtext( "(domain master browser name) " );
                        dbgtext( "on subnet %s.\n", subrec->subnet_name );
                        dbgtext( "Continuing with domain master code.\n" );
                }

                become_domain_master_stage1(subrec, name);
        } else {
                if( DEBUGLVL( 0 ) ) {
                        dbgtext( "become_domain_master_query_success:\n" );
                        dbgtext( "There is already a domain master browser at " );
                        dbgtext( "IP %s for workgroup %s ", inet_ntoa(ip), name );
                        dbgtext( "registered on subnet %s.\n", subrec->subnet_name );
                }
        }
}

/****************************************************************************
  Function called when a query for a WORKGROUP<1b> name fails.
  This is normally a success condition as it then allows us to register
  our own Domain Master Browser name.
  ****************************************************************************/

static void become_domain_master_query_fail(struct subnet_record *subrec,
                                    struct response_record *rrec,
                                    struct nmb_name *question_name, int fail_code)
{
        unstring name;

        /* If the query was unicast, and the error is not NAM_ERR (name didn't exist),
                then this is a failure. Otherwise, not finding the name is what we want. */

        if((subrec == unicast_subnet) && (fail_code != NAM_ERR)) {
                DEBUG(0,("become_domain_master_query_fail: Error %d returned when \
querying WINS server for name %s.\n", 
                        fail_code, nmb_namestr(question_name)));
                return;
        }

        /* Otherwise - not having the name allows us to register it. */
        pull_ascii_nstring(name, sizeof(name), question_name->name);
        become_domain_master_stage1(subrec, name);
}

/****************************************************************************
  Attempt to become a domain master browser on all broadcast subnets.
  ****************************************************************************/

static void become_domain_master_browser_bcast(const char *workgroup_name)
{
        struct subnet_record *subrec;

        for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) { 
                struct work_record *work = find_workgroup_on_subnet(subrec, workgroup_name);

                if (work && (work->dom_state == DOMAIN_NONE)) {
                        struct nmb_name nmbname;
                        make_nmb_name(&nmbname,workgroup_name,0x1b);

                        /*
                         * Check for our name on the given broadcast subnet first, only initiate
                         * further processing if we cannot find it.
                         */

                        if (find_name_on_subnet(subrec, &nmbname, FIND_SELF_NAME) == NULL) {
                                if( DEBUGLVL( 0 ) ) {
                                        dbgtext( "become_domain_master_browser_bcast:\n" );
                                        dbgtext( "Attempting to become domain master browser on " );
                                        dbgtext( "workgroup %s on subnet %s\n",
                                                workgroup_name, subrec->subnet_name );
                                }

                                /* Send out a query to establish whether there's a 
                                   domain controller on the local subnet. If not,
                                   we can become a domain controller. 
                                */

                                DEBUG(0,("become_domain_master_browser_bcast: querying subnet %s \
for domain master browser on workgroup %s\n", subrec->subnet_name, workgroup_name));

                                query_name(subrec, workgroup_name, nmbname.name_type,
                                        become_domain_master_query_success, 
                                        become_domain_master_query_fail,
                                        NULL);
                        }
                }
        }
}

/****************************************************************************
  Attempt to become a domain master browser by registering with WINS.
  ****************************************************************************/

static void become_domain_master_browser_wins(const char *workgroup_name)
{
        struct work_record *work;

        work = find_workgroup_on_subnet(unicast_subnet, workgroup_name);

        if (work && (work->dom_state == DOMAIN_NONE)) {
                struct nmb_name nmbname;

                make_nmb_name(&nmbname,workgroup_name,0x1b);

                /*
                 * Check for our name on the unicast subnet first, only initiate
                 * further processing if we cannot find it.
                 */

                if (find_name_on_subnet(unicast_subnet, &nmbname, FIND_SELF_NAME) == NULL) {
                        if( DEBUGLVL( 0 ) ) {
                                dbgtext( "become_domain_master_browser_wins:\n" );
                                dbgtext( "Attempting to become domain master browser " );
                                dbgtext( "on workgroup %s, subnet %s.\n",
                                        workgroup_name, unicast_subnet->subnet_name );
                        }

                        /* Send out a query to establish whether there's a 
                           domain master broswer registered with WINS. If not,
                           we can become a domain master browser. 
                        */

                        DEBUG(0,("become_domain_master_browser_wins: querying WINS server from IP %s \
for domain master browser name %s on workgroup %s\n",
                                inet_ntoa(unicast_subnet->myip), nmb_namestr(&nmbname), workgroup_name));

                        query_name(unicast_subnet, workgroup_name, nmbname.name_type,
                                become_domain_master_query_success,
                                become_domain_master_query_fail,
                                NULL);
                }
        }
}

/****************************************************************************
  Add the domain logon server and domain master browser names
  if we are set up to do so.
  **************************************************************************/

void add_domain_names(time_t t)
{
        static time_t lastrun = 0;

        if ((lastrun != 0) && (t < lastrun + (CHECK_TIME_ADD_DOM_NAMES * 60)))
                return;

        lastrun = t;

        /* Do the "internet group" - <1c> names. */
        if (lp_domain_logons())
                add_logon_names();

        /* Do the domain master names. */
        if(lp_domain_master()) {
                if(we_are_a_wins_client()) {
                        /* We register the WORKGROUP<1b> name with the WINS
                                server first, and call add_domain_master_bcast()
                                only if this is successful.

                                This results in domain logon services being gracefully provided,
                                as opposed to the aggressive nature of 1.9.16p2 to 1.9.16p11.
                                1.9.16p2 to 1.9.16p11 - due to a bug in namelogon.c,
                                cannot provide domain master / domain logon services.
                        */
                        become_domain_master_browser_wins(lp_workgroup());
                } else {
                        become_domain_master_browser_bcast(lp_workgroup());
                }
        }
}

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