source/nmbd/nmbd_become_dmb.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    NBT netbios routines and daemon - version 2
   4    Copyright (C) Andrew Tridgell 1994-1998
   5    Copyright (C) Luke Kenneth Casson Leighton 1994-1998
   6    Copyright (C) Jeremy Allison 1994-2003
   7
   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 2 of the License, or
  11    (at your option) any later version.
  12
  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.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22 */
  23
  24 #include "includes.h"
  25
  26 extern struct in_addr allones_ip;
  27
  28 extern uint16 samba_nb_type; /* Samba's NetBIOS type. */
  29
  30 static void become_domain_master_browser_bcast(const char *);
  31
  32 /****************************************************************************
  33   Fail to become a Domain Master Browser on a subnet.
  34   ****************************************************************************/
  35
  36 static void become_domain_master_fail(struct subnet_record *subrec,
  37                                       struct response_record *rrec,
  38                                       struct nmb_name *fail_name)
  39 {
  40         unstring failname;
  41         struct work_record *work;
  42         struct server_record *servrec;
  43
  44         pull_ascii_nstring(failname, sizeof(failname), fail_name->name);
  45         work = find_workgroup_on_subnet(subrec, failname);
  46         if(!work) {
  47                 DEBUG(0,("become_domain_master_fail: Error - cannot find \
  48 workgroup %s on subnet %s\n", failname, subrec->subnet_name));
  49                 return;
  50         }
  51
  52         /* Set the state back to DOMAIN_NONE. */
  53         work->dom_state = DOMAIN_NONE;
  54
  55         if((servrec = find_server_in_workgroup( work, global_myname())) == NULL) {
  56                 DEBUG(0,("become_domain_master_fail: Error - cannot find server %s \
  57 in workgroup %s on subnet %s\n",
  58                         global_myname(), work->work_group, subrec->subnet_name));
  59                 return;
  60         }
  61
  62         /* Update our server status. */
  63         servrec->serv.type &= ~SV_TYPE_DOMAIN_MASTER;
  64
  65         /* Tell the namelist writer to write out a change. */
  66         subrec->work_changed = True;
  67
  68         DEBUG(0,("become_domain_master_fail: Failed to become a domain master browser for \
  69 workgroup %s on subnet %s. Couldn't register name %s.\n",
  70                 work->work_group, subrec->subnet_name, nmb_namestr(fail_name)));
  71 }
  72
  73 /****************************************************************************
  74   Become a Domain Master Browser on a subnet.
  75   ****************************************************************************/
  76
  77 static void become_domain_master_stage2(struct subnet_record *subrec,
  78                                         struct userdata_struct *userdata,
  79                                         struct nmb_name *registered_name,
  80                                         uint16 nb_flags,
  81                                         int ttl, struct in_addr registered_ip)
  82 {
  83         unstring regname;
  84         struct work_record *work;
  85         struct server_record *servrec;
  86
  87         pull_ascii_nstring(regname, sizeof(regname), registered_name->name);
  88         work = find_workgroup_on_subnet( subrec, regname);
  89
  90         if(!work) {
  91                 DEBUG(0,("become_domain_master_stage2: Error - cannot find \
  92 workgroup %s on subnet %s\n", regname, subrec->subnet_name));
  93                 return;
  94         }
  95
  96         if((servrec = find_server_in_workgroup( work, global_myname())) == NULL) {
  97                 DEBUG(0,("become_domain_master_stage2: Error - cannot find server %s \
  98 in workgroup %s on subnet %s\n",
  99                 global_myname(), regname, subrec->subnet_name));
 100                 work->dom_state = DOMAIN_NONE;
 101                 return;
 102         }
 103
 104         /* Set the state in the workgroup structure. */
 105         work->dom_state = DOMAIN_MST; /* Become domain master. */
 106
 107         /* Update our server status. */
 108         servrec->serv.type |= (SV_TYPE_NT|SV_TYPE_DOMAIN_MASTER);
 109
 110         /* Tell the namelist writer to write out a change. */
 111         subrec->work_changed = True;
 112
 113         if( DEBUGLVL( 0 ) ) {
 114                 dbgtext( "*****\n\nSamba server %s ", global_myname() );
 115                 dbgtext( "is now a domain master browser for " );
 116                 dbgtext( "workgroup %s ", work->work_group );
 117                 dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
 118         }
 119
 120         if( subrec == unicast_subnet ) {
 121                 struct nmb_name nmbname;
 122                 struct in_addr my_first_ip;
 123                 struct in_addr *nip;
 124
 125                 /* Put our name and first IP address into the
 126                    workgroup struct as domain master browser. This
 127                    will stop us syncing with ourself if we are also
 128                    a local master browser. */
 129
 130                 make_nmb_name(&nmbname, global_myname(), 0x20);
 131
 132                 work->dmb_name = nmbname;
 133                 /* Pick the first interface ip address as the domain master browser ip. */
 134                 nip = iface_n_ip(0);
 135
 136                 if (!nip) {
 137                         DEBUG(0,("become_domain_master_stage2: Error. iface_n_ip returned NULL\n"));
 138                         return;
 139                 }
 140
 141                 my_first_ip = *nip;
 142
 143                 putip((char *)&work->dmb_addr, &my_first_ip);
 144
 145                 /* We successfully registered by unicast with the
 146                    WINS server.  We now expect to become the domain
 147                    master on the local subnets. If this fails, it's
 148                    probably a 1.9.16p2 to 1.9.16p11 server's fault.
 149
 150                    This is a configuration issue that should be addressed
 151                    by the network administrator - you shouldn't have
 152                    several machines configured as a domain master browser
 153                    for the same WINS scope (except if they are 1.9.17 or
 154                    greater, and you know what you're doing.
 155
 156                    see docs/DOMAIN.txt.
 157
 158                 */
 159                 become_domain_master_browser_bcast(work->work_group);
 160         } else {
 161                 /*
 162                  * Now we are a domain master on a broadcast subnet, we need to add
 163                  * the WORKGROUP<1b> name to the unicast subnet so that we can answer
 164                  * unicast requests sent to this name. This bug wasn't found for a while
 165                  * as it is strange to have a DMB without using WINS. JRA.
 166                  */
 167                 insert_permanent_name_into_unicast(subrec, registered_name, nb_flags);
 168         }
 169 }
 170
 171 /****************************************************************************
 172   Start the name registration process when becoming a Domain Master Browser
 173   on a subnet.
 174 ****************************************************************************/
 175
 176 static void become_domain_master_stage1(struct subnet_record *subrec, const char *wg_name)
 177 {
 178         struct work_record *work;
 179
 180         DEBUG(2,("become_domain_master_stage1: Becoming domain master browser for \
 181 workgroup %s on subnet %s\n", wg_name, subrec->subnet_name));
 182
 183         /* First, find the workgroup on the subnet. */
 184         if((work = find_workgroup_on_subnet( subrec, wg_name )) == NULL) {
 185                 DEBUG(0,("become_domain_master_stage1: Error - unable to find workgroup %s on subnet %s.\n",
 186                         wg_name, subrec->subnet_name));
 187                 return;
 188         }
 189
 190         DEBUG(3,("become_domain_master_stage1: go to first stage: register <1b> name\n"));
 191         work->dom_state = DOMAIN_WAIT;
 192
 193         /* WORKGROUP<1b> is the domain master browser name. */
 194         register_name(subrec, work->work_group,0x1b,samba_nb_type,
 195                         become_domain_master_stage2,
 196                         become_domain_master_fail, NULL);
 197 }
 198
 199 /****************************************************************************
 200   Function called when a query for a WORKGROUP<1b> name succeeds.
 201   This is normally a fail condition as it means there is already
 202   a domain master browser for a workgroup and we were trying to
 203   become one.
 204 ****************************************************************************/
 205
 206 static void become_domain_master_query_success(struct subnet_record *subrec,
 207                         struct userdata_struct *userdata,
 208                         struct nmb_name *nmbname, struct in_addr ip,
 209                         struct res_rec *rrec)
 210 {
 211         unstring name;
 212         pull_ascii_nstring(name, sizeof(name), nmbname->name);
 213
 214         /* If the given ip is not ours, then we can't become a domain
 215                 controler as the name is already registered.
 216         */
 217
 218         /* BUG note. Samba 1.9.16p11 servers seem to return the broadcast
 219                 address or zero ip for this query. Pretend this is ok. */
 220
 221         if(ismyip(ip) || ip_equal(allones_ip, ip) || is_zero_ip(ip)) {
 222                 if( DEBUGLVL( 3 ) ) {
 223                         dbgtext( "become_domain_master_query_success():\n" );
 224                         dbgtext( "Our address (%s) ", inet_ntoa(ip) );
 225                         dbgtext( "returned in query for name %s ", nmb_namestr(nmbname) );
 226                         dbgtext( "(domain master browser name) " );
 227                         dbgtext( "on subnet %s.\n", subrec->subnet_name );
 228                         dbgtext( "Continuing with domain master code.\n" );
 229                 }
 230
 231                 become_domain_master_stage1(subrec, name);
 232         } else {
 233                 if( DEBUGLVL( 0 ) ) {
 234                         dbgtext( "become_domain_master_query_success:\n" );
 235                         dbgtext( "There is already a domain master browser at " );
 236                         dbgtext( "IP %s for workgroup %s ", inet_ntoa(ip), name );
 237                         dbgtext( "registered on subnet %s.\n", subrec->subnet_name );
 238                 }
 239         }
 240 }
 241
 242 /****************************************************************************
 243   Function called when a query for a WORKGROUP<1b> name fails.
 244   This is normally a success condition as it then allows us to register
 245   our own Domain Master Browser name.
 246   ****************************************************************************/
 247
 248 static void become_domain_master_query_fail(struct subnet_record *subrec,
 249                                     struct response_record *rrec,
 250                                     struct nmb_name *question_name, int fail_code)
 251 {
 252         unstring name;
 253
 254         /* If the query was unicast, and the error is not NAM_ERR (name didn't exist),
 255                 then this is a failure. Otherwise, not finding the name is what we want. */
 256
 257         if((subrec == unicast_subnet) && (fail_code != NAM_ERR)) {
 258                 DEBUG(0,("become_domain_master_query_fail: Error %d returned when \
 259 querying WINS server for name %s.\n",
 260                         fail_code, nmb_namestr(question_name)));
 261                 return;
 262         }
 263
 264         /* Otherwise - not having the name allows us to register it. */
 265         pull_ascii_nstring(name, sizeof(name), question_name->name);
 266         become_domain_master_stage1(subrec, name);
 267 }
 268
 269 /****************************************************************************
 270   Attempt to become a domain master browser on all broadcast subnets.
 271   ****************************************************************************/
 272
 273 static void become_domain_master_browser_bcast(const char *workgroup_name)
 274 {
 275         struct subnet_record *subrec;
 276
 277         for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
 278                 struct work_record *work = find_workgroup_on_subnet(subrec, workgroup_name);
 279
 280                 if (work && (work->dom_state == DOMAIN_NONE)) {
 281                         struct nmb_name nmbname;
 282                         make_nmb_name(&nmbname,workgroup_name,0x1b);
 283
 284                         /*
 285                          * Check for our name on the given broadcast subnet first, only initiate
 286                          * further processing if we cannot find it.
 287                          */
 288
 289                         if (find_name_on_subnet(subrec, &nmbname, FIND_SELF_NAME) == NULL) {
 290                                 if( DEBUGLVL( 0 ) ) {
 291                                         dbgtext( "become_domain_master_browser_bcast:\n" );
 292                                         dbgtext( "Attempting to become domain master browser on " );
 293                                         dbgtext( "workgroup %s on subnet %s\n",
 294                                                 workgroup_name, subrec->subnet_name );
 295                                 }
 296
 297                                 /* Send out a query to establish whether there's a
 298                                    domain controller on the local subnet. If not,
 299                                    we can become a domain controller.
 300                                 */
 301
 302                                 DEBUG(0,("become_domain_master_browser_bcast: querying subnet %s \
 303 for domain master browser on workgroup %s\n", subrec->subnet_name, workgroup_name));
 304
 305                                 query_name(subrec, workgroup_name, nmbname.name_type,
 306                                         become_domain_master_query_success,
 307                                         become_domain_master_query_fail,
 308                                         NULL);
 309                         }
 310                 }
 311         }
 312 }
 313
 314 /****************************************************************************
 315   Attempt to become a domain master browser by registering with WINS.
 316   ****************************************************************************/
 317
 318 static void become_domain_master_browser_wins(const char *workgroup_name)
 319 {
 320         struct work_record *work;
 321
 322         work = find_workgroup_on_subnet(unicast_subnet, workgroup_name);
 323
 324         if (work && (work->dom_state == DOMAIN_NONE)) {
 325                 struct nmb_name nmbname;
 326
 327                 make_nmb_name(&nmbname,workgroup_name,0x1b);
 328
 329                 /*
 330                  * Check for our name on the unicast subnet first, only initiate
 331                  * further processing if we cannot find it.
 332                  */
 333
 334                 if (find_name_on_subnet(unicast_subnet, &nmbname, FIND_SELF_NAME) == NULL) {
 335                         if( DEBUGLVL( 0 ) ) {
 336                                 dbgtext( "become_domain_master_browser_wins:\n" );
 337                                 dbgtext( "Attempting to become domain master browser " );
 338                                 dbgtext( "on workgroup %s, subnet %s.\n",
 339                                         workgroup_name, unicast_subnet->subnet_name );
 340                         }
 341
 342                         /* Send out a query to establish whether there's a
 343                            domain master broswer registered with WINS. If not,
 344                            we can become a domain master browser.
 345                         */
 346
 347                         DEBUG(0,("become_domain_master_browser_wins: querying WINS server from IP %s \
 348 for domain master browser name %s on workgroup %s\n",
 349                                 inet_ntoa(unicast_subnet->myip), nmb_namestr(&nmbname), workgroup_name));
 350
 351                         query_name(unicast_subnet, workgroup_name, nmbname.name_type,
 352                                 become_domain_master_query_success,
 353                                 become_domain_master_query_fail,
 354                                 NULL);
 355                 }
 356         }
 357 }
 358
 359 /****************************************************************************
 360   Add the domain logon server and domain master browser names
 361   if we are set up to do so.
 362   **************************************************************************/
 363
 364 void add_domain_names(time_t t)
 365 {
 366         static time_t lastrun = 0;
 367
 368         if ((lastrun != 0) && (t < lastrun + (CHECK_TIME_ADD_DOM_NAMES * 60)))
 369                 return;
 370
 371         lastrun = t;
 372
 373         /* Do the "internet group" - <1c> names. */
 374         if (lp_domain_logons())
 375                 add_logon_names();
 376
 377         /* Do the domain master names. */
 378         if(lp_domain_master()) {
 379                 if(we_are_a_wins_client()) {
 380                         /* We register the WORKGROUP<1b> name with the WINS
 381                                 server first, and call add_domain_master_bcast()
 382                                 only if this is successful.
 383
 384                                 This results in domain logon services being gracefully provided,
 385                                 as opposed to the aggressive nature of 1.9.16p2 to 1.9.16p11.
 386                                 1.9.16p2 to 1.9.16p11 - due to a bug in namelogon.c,
 387                                 cannot provide domain master / domain logon services.
 388                         */
 389                         become_domain_master_browser_wins(lp_workgroup());
 390                 } else {
 391                         become_domain_master_browser_bcast(lp_workgroup());
 392                 }
 393         }
 394 }