source/nmbd/nmbd_become_lmb.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 uint16 samba_nb_type; /* Samba's NetBIOS name type. */
  27
  28 /*******************************************************************
  29  Utility function to add a name to the unicast subnet, or add in
  30  our IP address if it already exists.
  31 ******************************************************************/
  32
  33 void insert_permanent_name_into_unicast( struct subnet_record *subrec,
  34                                                 struct nmb_name *nmbname, uint16 nb_type )
  35 {
  36         unstring name;
  37         struct name_record *namerec;
  38
  39         if((namerec = find_name_on_subnet(unicast_subnet, nmbname, FIND_SELF_NAME)) == NULL) {
  40                 pull_ascii_nstring(name, sizeof(name), nmbname->name);
  41                 /* The name needs to be created on the unicast subnet. */
  42                 (void)add_name_to_subnet( unicast_subnet, name,
  43                                 nmbname->name_type, nb_type,
  44                                 PERMANENT_TTL, PERMANENT_NAME, 1, &subrec->myip);
  45         } else {
  46                 /* The name already exists on the unicast subnet. Add our local
  47                 IP for the given broadcast subnet to the name. */
  48                 add_ip_to_name_record( namerec, subrec->myip);
  49         }
  50 }
  51
  52 /*******************************************************************
  53  Utility function to remove a name from the unicast subnet.
  54 ******************************************************************/
  55
  56 static void remove_permanent_name_from_unicast( struct subnet_record *subrec,
  57                                                 struct nmb_name *nmbname )
  58 {
  59         struct name_record *namerec;
  60
  61         if((namerec = find_name_on_subnet(unicast_subnet, nmbname, FIND_SELF_NAME)) != NULL) {
  62                 /* Remove this broadcast subnet IP address from the name. */
  63                 remove_ip_from_name_record( namerec, subrec->myip);
  64                 if(namerec->data.num_ips == 0)
  65                         remove_name_from_namelist( unicast_subnet, namerec);
  66         }
  67 }
  68
  69 /*******************************************************************
  70  Utility function always called to set our workgroup and server
  71  state back to potential browser, or none.
  72 ******************************************************************/
  73
  74 static void reset_workgroup_state( struct subnet_record *subrec, const char *workgroup_name,
  75                                    BOOL force_new_election )
  76 {
  77         struct work_record *work;
  78         struct server_record *servrec;
  79         struct nmb_name nmbname;
  80
  81         if((work = find_workgroup_on_subnet( subrec, workgroup_name)) == NULL) {
  82                 DEBUG(0,("reset_workgroup_state: Error - cannot find workgroup %s on \
  83 subnet %s.\n", workgroup_name, subrec->subnet_name ));
  84                 return;
  85         }
  86
  87         if((servrec = find_server_in_workgroup( work, global_myname())) == NULL) {
  88                 DEBUG(0,("reset_workgroup_state: Error - cannot find server %s \
  89 in workgroup %s on subnet %s\n",
  90                         global_myname(), work->work_group, subrec->subnet_name));
  91                 work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
  92                 return;
  93         }
  94
  95         /* Update our server status - remove any master flag and replace
  96                 it with the potential browser flag. */
  97         servrec->serv.type &= ~SV_TYPE_MASTER_BROWSER;
  98         servrec->serv.type |= (lp_local_master() ? SV_TYPE_POTENTIAL_BROWSER : 0);
  99
 100         /* Tell the namelist writer to write out a change. */
 101         subrec->work_changed = True;
 102
 103         /* Reset our election flags. */
 104         work->ElectionCriterion &= ~0x4;
 105
 106         work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
 107
 108         /* Forget who the local master browser was for
 109                 this workgroup. */
 110
 111         set_workgroup_local_master_browser_name( work, "");
 112
 113         /*
 114          * Ensure the IP address of this subnet is not registered as one
 115          * of the IP addresses of the WORKGROUP<1d> name on the unicast
 116          * subnet. This undoes what we did below when we became a local
 117          * master browser.
 118          */
 119
 120         make_nmb_name(&nmbname, work->work_group, 0x1d);
 121
 122         remove_permanent_name_from_unicast( subrec, &nmbname);
 123
 124         if(force_new_election)
 125                 work->needelection = True;
 126 }
 127
 128 /*******************************************************************
 129   Unbecome the local master browser name release success function.
 130 ******************************************************************/
 131
 132 static void unbecome_local_master_success(struct subnet_record *subrec,
 133                              struct userdata_struct *userdata,
 134                              struct nmb_name *released_name,
 135                              struct in_addr released_ip)
 136 {
 137         BOOL force_new_election = False;
 138         unstring relname;
 139
 140         memcpy((char *)&force_new_election, userdata->data, sizeof(BOOL));
 141
 142         DEBUG(3,("unbecome_local_master_success: released name %s.\n",
 143                 nmb_namestr(released_name)));
 144
 145         /* Now reset the workgroup and server state. */
 146         pull_ascii_nstring(relname, sizeof(relname), released_name->name);
 147         reset_workgroup_state( subrec, relname, force_new_election );
 148
 149         if( DEBUGLVL( 0 ) ) {
 150                 dbgtext( "*****\n\n" );
 151                 dbgtext( "Samba name server %s ", global_myname() );
 152                 dbgtext( "has stopped being a local master browser " );
 153                 dbgtext( "for workgroup %s ", relname );
 154                 dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
 155         }
 156
 157 }
 158
 159 /*******************************************************************
 160   Unbecome the local master browser name release fail function.
 161 ******************************************************************/
 162
 163 static void unbecome_local_master_fail(struct subnet_record *subrec, struct response_record *rrec,
 164                        struct nmb_name *fail_name)
 165 {
 166         struct name_record *namerec;
 167         struct userdata_struct *userdata = rrec->userdata;
 168         BOOL force_new_election = False;
 169         unstring failname;
 170
 171         memcpy((char *)&force_new_election, userdata->data, sizeof(BOOL));
 172
 173         DEBUG(0,("unbecome_local_master_fail: failed to release name %s. \
 174 Removing from namelist anyway.\n", nmb_namestr(fail_name)));
 175
 176         /* Do it anyway. */
 177         namerec = find_name_on_subnet(subrec, fail_name, FIND_SELF_NAME);
 178         if(namerec)
 179                 remove_name_from_namelist(subrec, namerec);
 180
 181         /* Now reset the workgroup and server state. */
 182         pull_ascii_nstring(failname, sizeof(failname), fail_name->name);
 183         reset_workgroup_state( subrec, failname, force_new_election );
 184
 185         if( DEBUGLVL( 0 ) ) {
 186                 dbgtext( "*****\n\n" );
 187                 dbgtext( "Samba name server %s ", global_myname() );
 188                 dbgtext( "has stopped being a local master browser " );
 189                 dbgtext( "for workgroup %s ", failname );
 190                 dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
 191         }
 192 }
 193
 194 /*******************************************************************
 195  Utility function to remove the WORKGROUP<1d> name.
 196 ******************************************************************/
 197
 198 static void release_1d_name( struct subnet_record *subrec, const char *workgroup_name,
 199                              BOOL force_new_election)
 200 {
 201         struct nmb_name nmbname;
 202         struct name_record *namerec;
 203
 204         make_nmb_name(&nmbname, workgroup_name, 0x1d);
 205         if((namerec = find_name_on_subnet( subrec, &nmbname, FIND_SELF_NAME))!=NULL) {
 206                 struct userdata_struct *userdata;
 207                 size_t size = sizeof(struct userdata_struct) + sizeof(BOOL);
 208
 209                 if((userdata = (struct userdata_struct *)SMB_MALLOC(size)) == NULL) {
 210                         DEBUG(0,("release_1d_name: malloc fail.\n"));
 211                         return;
 212                 }
 213
 214                 userdata->copy_fn = NULL;
 215                 userdata->free_fn = NULL;
 216                 userdata->userdata_len = sizeof(BOOL);
 217                 memcpy((char *)userdata->data, &force_new_election, sizeof(BOOL));
 218
 219                 release_name(subrec, namerec,
 220                         unbecome_local_master_success,
 221                         unbecome_local_master_fail,
 222                         userdata);
 223
 224                 zero_free(userdata, size);
 225         }
 226 }
 227
 228 /*******************************************************************
 229  Unbecome the local master browser MSBROWSE name release success function.
 230 ******************************************************************/
 231
 232 static void release_msbrowse_name_success(struct subnet_record *subrec,
 233                       struct userdata_struct *userdata,
 234                       struct nmb_name *released_name,
 235                       struct in_addr released_ip)
 236 {
 237         DEBUG(4,("release_msbrowse_name_success: Released name %s on subnet %s\n.",
 238                 nmb_namestr(released_name), subrec->subnet_name ));
 239
 240         /* Remove the permanent MSBROWSE name added into the unicast subnet. */
 241         remove_permanent_name_from_unicast( subrec, released_name);
 242 }
 243
 244 /*******************************************************************
 245  Unbecome the local master browser MSBROWSE name release fail function.
 246 ******************************************************************/
 247
 248 static void release_msbrowse_name_fail( struct subnet_record *subrec,
 249                        struct response_record *rrec,
 250                        struct nmb_name *fail_name)
 251 {
 252         struct name_record *namerec;
 253
 254         DEBUG(4,("release_msbrowse_name_fail: Failed to release name %s on subnet %s\n.",
 255                 nmb_namestr(fail_name), subrec->subnet_name ));
 256
 257         /* Release the name anyway. */
 258         namerec = find_name_on_subnet(subrec, fail_name, FIND_SELF_NAME);
 259         if(namerec)
 260                 remove_name_from_namelist(subrec, namerec);
 261
 262         /* Remove the permanent MSBROWSE name added into the unicast subnet. */
 263         remove_permanent_name_from_unicast( subrec, fail_name);
 264 }
 265
 266 /*******************************************************************
 267   Unbecome the local master browser. If force_new_election is true, restart
 268   the election process after we've unbecome the local master.
 269 ******************************************************************/
 270
 271 void unbecome_local_master_browser(struct subnet_record *subrec, struct work_record *work,
 272                                    BOOL force_new_election)
 273 {
 274         struct name_record *namerec;
 275         struct nmb_name nmbname;
 276
 277   /* Sanity check. */
 278
 279         DEBUG(2,("unbecome_local_master_browser: unbecoming local master for workgroup %s \
 280 on subnet %s\n",work->work_group, subrec->subnet_name));
 281
 282         if(find_server_in_workgroup( work, global_myname()) == NULL) {
 283                 DEBUG(0,("unbecome_local_master_browser: Error - cannot find server %s \
 284 in workgroup %s on subnet %s\n",
 285                         global_myname(), work->work_group, subrec->subnet_name));
 286                         work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
 287                 return;
 288         }
 289
 290         /* Set the state to unbecoming. */
 291         work->mst_state = MST_UNBECOMING_MASTER;
 292
 293         /*
 294          * Release the WORKGROUP<1d> name asap to allow another machine to
 295          * claim it.
 296          */
 297
 298         release_1d_name( subrec, work->work_group, force_new_election);
 299
 300         /* Deregister any browser names we may have. */
 301         make_nmb_name(&nmbname, MSBROWSE, 0x1);
 302         if((namerec = find_name_on_subnet( subrec, &nmbname, FIND_SELF_NAME))!=NULL) {
 303                 release_name(subrec, namerec,
 304                         release_msbrowse_name_success,
 305                         release_msbrowse_name_fail,
 306                         NULL);
 307         }
 308
 309         /*
 310          * Ensure we have sent and processed these release packets
 311          * before returning - we don't want to process any election
 312          * packets before dealing with the 1d release.
 313          */
 314
 315         retransmit_or_expire_response_records(time(NULL));
 316 }
 317
 318 /****************************************************************************
 319   Success in registering the WORKGROUP<1d> name.
 320   We are now *really* a local master browser.
 321   ****************************************************************************/
 322
 323 static void become_local_master_stage2(struct subnet_record *subrec,
 324                                         struct userdata_struct *userdata,
 325                                         struct nmb_name *registered_name,
 326                                         uint16 nb_flags,
 327                                         int ttl, struct in_addr registered_ip)
 328 {
 329         int i = 0;
 330         struct server_record *sl;
 331         struct work_record *work;
 332         struct server_record *servrec;
 333         unstring regname;
 334
 335         pull_ascii_nstring(regname, sizeof(regname), registered_name->name);
 336         work = find_workgroup_on_subnet( subrec, regname);
 337
 338         if(!work) {
 339                 DEBUG(0,("become_local_master_stage2: Error - cannot find \
 340 workgroup %s on subnet %s\n", regname, subrec->subnet_name));
 341                 return;
 342         }
 343
 344         if((servrec = find_server_in_workgroup( work, global_myname())) == NULL) {
 345                 DEBUG(0,("become_local_master_stage2: Error - cannot find server %s \
 346 in workgroup %s on subnet %s\n",
 347                         global_myname(), regname, subrec->subnet_name));
 348                         work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
 349                 return;
 350         }
 351
 352         DEBUG(3,("become_local_master_stage2: registered as master browser for workgroup %s \
 353 on subnet %s\n", work->work_group, subrec->subnet_name));
 354
 355         work->mst_state = MST_BROWSER; /* registering WORKGROUP(1d) succeeded */
 356
 357         /* update our server status */
 358         servrec->serv.type |= SV_TYPE_MASTER_BROWSER;
 359         servrec->serv.type &= ~SV_TYPE_POTENTIAL_BROWSER;
 360
 361         /* Tell the namelist writer to write out a change. */
 362         subrec->work_changed = True;
 363
 364         /* Add this name to the workgroup as local master browser. */
 365         set_workgroup_local_master_browser_name( work, global_myname());
 366
 367         /* Count the number of servers we have on our list. If it's
 368                 less than 10 (just a heuristic) request the servers
 369                 to announce themselves.
 370         */
 371         for( sl = work->serverlist; sl != NULL; sl = sl->next)
 372                 i++;
 373
 374         if (i < 10) {
 375                 /* Ask all servers on our local net to announce to us. */
 376                 broadcast_announce_request(subrec, work);
 377         }
 378
 379         /*
 380          * Now we are a local master on a broadcast subnet, we need to add
 381          * the WORKGROUP<1d> name to the unicast subnet so that we can answer
 382          * unicast requests sent to this name. We can create this name directly on
 383          * the unicast subnet as a WINS server always returns true when registering
 384          * this name, and discards the registration. We use the number of IP
 385          * addresses registered to this name as a reference count, as we
 386          * remove this broadcast subnet IP address from it when we stop becoming a local
 387          * master browser for this broadcast subnet.
 388          */
 389
 390         insert_permanent_name_into_unicast( subrec, registered_name, nb_flags);
 391
 392         /* Reset the announce master browser timer so that we try and tell a domain
 393                 master browser as soon as possible that we are a local master browser. */
 394         reset_announce_timer();
 395
 396         if( DEBUGLVL( 0 ) ) {
 397                 dbgtext( "*****\n\n" );
 398                 dbgtext( "Samba name server %s ", global_myname() );
 399                 dbgtext( "is now a local master browser " );
 400                 dbgtext( "for workgroup %s ", work->work_group );
 401                 dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
 402         }
 403 }
 404
 405 /****************************************************************************
 406   Failed to register the WORKGROUP<1d> name.
 407   ****************************************************************************/
 408
 409 static void become_local_master_fail2(struct subnet_record *subrec,
 410                                       struct response_record *rrec,
 411                                       struct nmb_name *fail_name)
 412 {
 413         unstring failname;
 414         struct work_record *work;
 415
 416         DEBUG(0,("become_local_master_fail2: failed to register name %s on subnet %s. \
 417 Failed to become a local master browser.\n", nmb_namestr(fail_name), subrec->subnet_name));
 418
 419         pull_ascii_nstring(failname, sizeof(failname), fail_name->name);
 420         work = find_workgroup_on_subnet( subrec, failname);
 421
 422         if(!work) {
 423                 DEBUG(0,("become_local_master_fail2: Error - cannot find \
 424 workgroup %s on subnet %s\n", failname, subrec->subnet_name));
 425                 return;
 426         }
 427
 428         /* Roll back all the way by calling unbecome_local_master_browser(). */
 429         unbecome_local_master_browser(subrec, work, False);
 430 }
 431
 432 /****************************************************************************
 433   Success in registering the MSBROWSE name.
 434   ****************************************************************************/
 435
 436 static void become_local_master_stage1(struct subnet_record *subrec,
 437                                         struct userdata_struct *userdata,
 438                                         struct nmb_name *registered_name,
 439                                         uint16 nb_flags,
 440                                         int ttl, struct in_addr registered_ip)
 441 {
 442         char *work_name = userdata->data;
 443         struct work_record *work = find_workgroup_on_subnet( subrec, work_name);
 444
 445         if(!work) {
 446                 DEBUG(0,("become_local_master_stage1: Error - cannot find \
 447                         %s on subnet %s\n", work_name, subrec->subnet_name));
 448                 return;
 449         }
 450
 451         DEBUG(3,("become_local_master_stage1: go to stage 2: register the %s<1d> name.\n",
 452                 work->work_group));
 453
 454         work->mst_state = MST_MSB; /* Registering MSBROWSE was successful. */
 455
 456         /*
 457          * We registered the MSBROWSE name on a broadcast subnet, now need to add
 458          * the MSBROWSE name to the unicast subnet so that we can answer
 459          * unicast requests sent to this name. We create this name directly on
 460          * the unicast subnet.
 461          */
 462
 463         insert_permanent_name_into_unicast( subrec, registered_name, nb_flags);
 464
 465         /* Attempt to register the WORKGROUP<1d> name. */
 466         register_name(subrec, work->work_group,0x1d,samba_nb_type,
 467                 become_local_master_stage2,
 468                 become_local_master_fail2,
 469                 NULL);
 470 }
 471
 472 /****************************************************************************
 473   Failed to register the MSBROWSE name.
 474   ****************************************************************************/
 475
 476 static void become_local_master_fail1(struct subnet_record *subrec,
 477                                       struct response_record *rrec,
 478                                       struct nmb_name *fail_name)
 479 {
 480         char *work_name = rrec->userdata->data;
 481         struct work_record *work = find_workgroup_on_subnet(subrec, work_name);
 482
 483         if(!work) {
 484                 DEBUG(0,("become_local_master_fail1: Error - cannot find \
 485 workgroup %s on subnet %s\n", work_name, subrec->subnet_name));
 486                 return;
 487         }
 488
 489         if(find_server_in_workgroup(work, global_myname()) == NULL) {
 490                 DEBUG(0,("become_local_master_fail1: Error - cannot find server %s \
 491 in workgroup %s on subnet %s\n",
 492                         global_myname(), work->work_group, subrec->subnet_name));
 493                 return;
 494         }
 495
 496         reset_workgroup_state( subrec, work->work_group, False );
 497
 498         DEBUG(0,("become_local_master_fail1: Failed to become a local master browser for \
 499 workgroup %s on subnet %s. Couldn't register name %s.\n",
 500                 work->work_group, subrec->subnet_name, nmb_namestr(fail_name)));
 501 }
 502
 503 /******************************************************************
 504   Become the local master browser on a subnet.
 505   This gets called if we win an election on this subnet.
 506
 507   Stage 1: mst_state was MST_POTENTIAL - go to MST_BACK register ^1^2__MSBROWSE__^2^1.
 508   Stage 2: mst_state was MST_BACKUP  - go to MST_MSB  and register WORKGROUP<1d>.
 509   Stage 3: mst_state was MST_MSB  - go to MST_BROWSER.
 510 ******************************************************************/
 511
 512 void become_local_master_browser(struct subnet_record *subrec, struct work_record *work)
 513 {
 514         struct userdata_struct *userdata;
 515         size_t size = sizeof(struct userdata_struct) + sizeof(fstring) + 1;
 516
 517         /* Sanity check. */
 518         if (!lp_local_master()) {
 519                 DEBUG(0,("become_local_master_browser: Samba not configured as a local master browser.\n"));
 520                 return;
 521         }
 522
 523         if(!AM_POTENTIAL_MASTER_BROWSER(work)) {
 524                 DEBUG(2,("become_local_master_browser: Awaiting potential browser state. Current state is %d\n",
 525                         work->mst_state ));
 526                 return;
 527         }
 528
 529         if(find_server_in_workgroup( work, global_myname()) == NULL) {
 530                 DEBUG(0,("become_local_master_browser: Error - cannot find server %s \
 531 in workgroup %s on subnet %s\n",
 532                         global_myname(), work->work_group, subrec->subnet_name));
 533                 return;
 534         }
 535
 536         DEBUG(2,("become_local_master_browser: Starting to become a master browser for workgroup \
 537 %s on subnet %s\n", work->work_group, subrec->subnet_name));
 538
 539         DEBUG(3,("become_local_master_browser: first stage - attempt to register ^1^2__MSBROWSE__^2^1\n"));
 540         work->mst_state = MST_BACKUP; /* an election win was successful */
 541
 542         work->ElectionCriterion |= 0x5;
 543
 544         /* Tell the namelist writer to write out a change. */
 545         subrec->work_changed = True;
 546
 547         /* Setup the userdata_struct. */
 548         if((userdata = (struct userdata_struct *)SMB_MALLOC(size)) == NULL) {
 549                 DEBUG(0,("become_local_master_browser: malloc fail.\n"));
 550                 return;
 551         }
 552
 553         userdata->copy_fn = NULL;
 554         userdata->free_fn = NULL;
 555         userdata->userdata_len = strlen(work->work_group)+1;
 556         overmalloc_safe_strcpy(userdata->data, work->work_group, size - sizeof(*userdata) - 1);
 557
 558         /* Register the special browser group name. */
 559         register_name(subrec, MSBROWSE, 0x01, samba_nb_type|NB_GROUP,
 560                 become_local_master_stage1,
 561                 become_local_master_fail1,
 562                 userdata);
 563
 564         zero_free(userdata, size);
 565 }
 566
 567 /***************************************************************
 568  Utility function to set the local master browser name. Does
 569  some sanity checking as old versions of Samba seem to sometimes
 570  say that the master browser name for a workgroup is the same
 571  as the workgroup name.
 572 ****************************************************************/
 573
 574 void set_workgroup_local_master_browser_name( struct work_record *work, const char *newname)
 575 {
 576         DEBUG(5,("set_workgroup_local_master_browser_name: setting local master name to '%s' \
 577 for workgroup %s.\n", newname, work->work_group ));
 578
 579 #if 0
 580   /*
 581    * Apparently some sites use the workgroup name as the local
 582    * master browser name. Arrrrggghhhhh ! (JRA).
 583    */
 584   if(strequal( work->work_group, newname))
 585   {
 586     DEBUG(5, ("set_workgroup_local_master_browser_name: Refusing to set \
 587 local_master_browser_name for workgroup %s to workgroup name.\n",
 588          work->work_group ));
 589     return;
 590   }
 591 #endif
 592
 593         unstrcpy(work->local_master_browser_name, newname);
 594 }