source/nmbd/nmbd_become_lmb.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    NBT netbios routines and daemon - version 2
   5    Copyright (C) Andrew Tridgell 1994-1998
   6    Copyright (C) Luke Kenneth Casson Leighton 1994-1998
   7    Copyright (C) Jeremy Allison 1994-1998
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22
  23 */
  24
  25 #include "includes.h"
  26
  27 extern pstring global_myname;
  28
  29 extern uint16 samba_nb_type; /* Samba's NetBIOS name type. */
  30
  31 /*******************************************************************
  32  Utility function to add a name to the unicast subnet, or add in
  33  our IP address if it already exists.
  34 ******************************************************************/
  35
  36 void insert_permanent_name_into_unicast( struct subnet_record *subrec,
  37                                                 struct nmb_name *nmbname, uint16 nb_type )
  38 {
  39   struct name_record *namerec;
  40
  41   if((namerec = find_name_on_subnet(unicast_subnet, nmbname, FIND_SELF_NAME)) == NULL)
  42   {
  43     /* The name needs to be created on the unicast subnet. */
  44     (void)add_name_to_subnet( unicast_subnet, nmbname->name,
  45                               nmbname->name_type, nb_type,
  46                               PERMANENT_TTL, PERMANENT_NAME, 1, &subrec->myip);
  47   }
  48   else
  49   {
  50     /* The name already exists on the unicast subnet. Add our local
  51        IP for the given broadcast subnet to the name. */
  52     add_ip_to_name_record( namerec, subrec->myip);
  53   }
  54 }
  55
  56 /*******************************************************************
  57  Utility function to remove a name from the unicast subnet.
  58 ******************************************************************/
  59
  60 static void remove_permanent_name_from_unicast( struct subnet_record *subrec,
  61                                                 struct nmb_name *nmbname )
  62 {
  63   struct name_record *namerec;
  64
  65   if((namerec = find_name_on_subnet(unicast_subnet, nmbname, FIND_SELF_NAME)) != NULL)
  66   {
  67     /* Remove this broadcast subnet IP address from the name. */
  68     remove_ip_from_name_record( namerec, subrec->myip);
  69     if(namerec->data.num_ips == 0)
  70       remove_name_from_namelist( unicast_subnet, namerec);
  71   }
  72 }
  73
  74 /*******************************************************************
  75  Utility function always called to set our workgroup and server
  76  state back to potential browser, or none.
  77 ******************************************************************/
  78
  79 static void reset_workgroup_state( struct subnet_record *subrec, char *workgroup_name,
  80                                    BOOL force_new_election )
  81 {
  82   struct work_record *work;
  83   struct server_record *servrec;
  84   struct nmb_name nmbname;
  85
  86   if((work = find_workgroup_on_subnet( subrec, workgroup_name)) == NULL)
  87   {
  88     DEBUG(0,("reset_workgroup_state: Error - cannot find workgroup %s on \
  89 subnet %s.\n", workgroup_name, subrec->subnet_name ));
  90     return;
  91   }
  92
  93   if((servrec = find_server_in_workgroup( work, global_myname)) == NULL)
  94   {
  95     DEBUG(0,("reset_workgroup_state: Error - cannot find server %s \
  96 in workgroup %s on subnet %s\n",
  97        global_myname, work->work_group, subrec->subnet_name));
  98     work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
  99     return;
 100   }
 101
 102   /* Update our server status - remove any master flag and replace
 103    it with the potential browser flag. */
 104   servrec->serv.type &= ~SV_TYPE_MASTER_BROWSER;
 105   servrec->serv.type |= (lp_local_master() ? SV_TYPE_POTENTIAL_BROWSER : 0);
 106
 107   /* Tell the namelist writer to write out a change. */
 108   subrec->work_changed = True;
 109
 110   /* Reset our election flags. */
 111   work->ElectionCriterion &= ~0x4;
 112
 113   work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
 114
 115   /* Forget who the local master browser was for
 116      this workgroup. */
 117
 118   set_workgroup_local_master_browser_name( work, "");
 119
 120   /*
 121    * Ensure the IP address of this subnet is not registered as one
 122    * of the IP addresses of the WORKGROUP<1d> name on the unicast
 123    * subnet. This undoes what we did below when we became a local
 124    * master browser.
 125    */
 126
 127   make_nmb_name(&nmbname, work->work_group, 0x1d);
 128
 129   remove_permanent_name_from_unicast( subrec, &nmbname);
 130
 131   if(force_new_election)
 132     work->needelection = True;
 133 }
 134
 135 /*******************************************************************
 136   Unbecome the local master browser name release success function.
 137 ******************************************************************/
 138
 139 static void unbecome_local_master_success(struct subnet_record *subrec,
 140                              struct userdata_struct *userdata,
 141                              struct nmb_name *released_name,
 142                              struct in_addr released_ip)
 143 {
 144   BOOL force_new_election = False;
 145
 146   memcpy((char *)&force_new_election, userdata->data, sizeof(BOOL));
 147
 148   DEBUG(3,("unbecome_local_master_success: released name %s.\n",
 149              nmb_namestr(released_name)));
 150
 151   /* Now reset the workgroup and server state. */
 152   reset_workgroup_state( subrec, released_name->name, force_new_election );
 153
 154   if( DEBUGLVL( 0 ) )
 155   {
 156     dbgtext( "*****\n\n" );
 157     dbgtext( "Samba name server %s ", global_myname );
 158     dbgtext( "has stopped being a local master browser " );
 159     dbgtext( "for workgroup %s ", released_name->name );
 160     dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
 161   }
 162
 163 }
 164
 165 /*******************************************************************
 166   Unbecome the local master browser name release fail function.
 167 ******************************************************************/
 168
 169 static void unbecome_local_master_fail(struct subnet_record *subrec, struct response_record *rrec,
 170                        struct nmb_name *fail_name)
 171 {
 172   struct name_record *namerec;
 173   struct userdata_struct *userdata = rrec->userdata;
 174   BOOL force_new_election = False;
 175
 176   memcpy((char *)&force_new_election, userdata->data, sizeof(BOOL));
 177
 178   DEBUG(0,("unbecome_local_master_fail: failed to release name %s. \
 179 Removing from namelist anyway.\n", nmb_namestr(fail_name)));
 180
 181   /* Do it anyway. */
 182   namerec = find_name_on_subnet(subrec, fail_name, FIND_SELF_NAME);
 183   if(namerec)
 184     remove_name_from_namelist(subrec, namerec);
 185
 186   /* Now reset the workgroup and server state. */
 187   reset_workgroup_state( subrec, fail_name->name, force_new_election );
 188
 189   if( DEBUGLVL( 0 ) )
 190   {
 191     dbgtext( "*****\n\n" );
 192     dbgtext( "Samba name server %s ", global_myname );
 193     dbgtext( "has stopped being a local master browser " );
 194     dbgtext( "for workgroup %s ", fail_name->name );
 195     dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
 196   }
 197 }
 198
 199 /*******************************************************************
 200  Utility function to remove the WORKGROUP<1d> name.
 201 ******************************************************************/
 202
 203 static void release_1d_name( struct subnet_record *subrec, char *workgroup_name,
 204                              BOOL force_new_election)
 205 {
 206   struct nmb_name nmbname;
 207   struct name_record *namerec;
 208
 209   make_nmb_name(&nmbname, workgroup_name, 0x1d);
 210   if((namerec = find_name_on_subnet( subrec, &nmbname, FIND_SELF_NAME))!=NULL)
 211   {
 212     struct userdata_struct *userdata;
 213     int size = sizeof(struct userdata_struct) + sizeof(BOOL);
 214
 215     if((userdata = (struct userdata_struct *)malloc(size)) == NULL)
 216     {
 217       DEBUG(0,("release_1d_name: malloc fail.\n"));
 218       return;
 219     }
 220
 221     userdata->copy_fn = NULL;
 222     userdata->free_fn = NULL;
 223     userdata->userdata_len = sizeof(BOOL);
 224     memcpy((char *)userdata->data, &force_new_election, sizeof(BOOL));
 225
 226     release_name(subrec, namerec,
 227                  unbecome_local_master_success,
 228                  unbecome_local_master_fail,
 229                  userdata);
 230
 231     zero_free(userdata, size);
 232   }
 233 }
 234
 235 /*******************************************************************
 236  Unbecome the local master browser MSBROWSE name release success function.
 237 ******************************************************************/
 238
 239 static void release_msbrowse_name_success(struct subnet_record *subrec,
 240                       struct userdata_struct *userdata,
 241                       struct nmb_name *released_name,
 242                       struct in_addr released_ip)
 243 {
 244   DEBUG(4,("release_msbrowse_name_success: Released name %s on subnet %s\n.",
 245            nmb_namestr(released_name), subrec->subnet_name ));
 246
 247   /* Remove the permanent MSBROWSE name added into the unicast subnet. */
 248   remove_permanent_name_from_unicast( subrec, released_name);
 249 }
 250
 251 /*******************************************************************
 252  Unbecome the local master browser MSBROWSE name release fail function.
 253 ******************************************************************/
 254
 255 static void release_msbrowse_name_fail( struct subnet_record *subrec,
 256                        struct response_record *rrec,
 257                        struct nmb_name *fail_name)
 258 {
 259   struct name_record *namerec;
 260
 261   DEBUG(4,("release_msbrowse_name_fail: Failed to release name %s on subnet %s\n.",
 262            nmb_namestr(fail_name), subrec->subnet_name ));
 263
 264   /* Release the name anyway. */
 265   namerec = find_name_on_subnet(subrec, fail_name, FIND_SELF_NAME);
 266   if(namerec)
 267     remove_name_from_namelist(subrec, namerec);
 268
 269   /* Remove the permanent MSBROWSE name added into the unicast subnet. */
 270   remove_permanent_name_from_unicast( subrec, fail_name);
 271 }
 272
 273 /*******************************************************************
 274   Unbecome the local master browser. If force_new_election is true, restart
 275   the election process after we've unbecome the local master.
 276 ******************************************************************/
 277
 278 void unbecome_local_master_browser(struct subnet_record *subrec, struct work_record *work,
 279                                    BOOL force_new_election)
 280 {
 281   struct name_record *namerec;
 282   struct nmb_name nmbname;
 283
 284   /* Sanity check. */
 285
 286   DEBUG(2,("unbecome_local_master_browser: unbecoming local master for workgroup %s \
 287 on subnet %s\n",work->work_group, subrec->subnet_name));
 288
 289   if(find_server_in_workgroup( work, global_myname) == NULL)
 290   {
 291     DEBUG(0,("unbecome_local_master_browser: Error - cannot find server %s \
 292 in workgroup %s on subnet %s\n",
 293        global_myname, work->work_group, subrec->subnet_name));
 294     work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
 295     return;
 296   }
 297
 298   /* Set the state to unbecoming. */
 299   work->mst_state = MST_UNBECOMING_MASTER;
 300
 301   /*
 302    * Release the WORKGROUP<1d> name asap to allow another machine to
 303    * claim it.
 304    */
 305
 306   release_1d_name( subrec, work->work_group, force_new_election);
 307
 308   /* Deregister any browser names we may have. */
 309   make_nmb_name(&nmbname, MSBROWSE, 0x1);
 310   if((namerec = find_name_on_subnet( subrec, &nmbname, FIND_SELF_NAME))!=NULL)
 311   {
 312     release_name(subrec, namerec,
 313                  release_msbrowse_name_success,
 314                  release_msbrowse_name_fail,
 315                  NULL);
 316   }
 317
 318   /*
 319    * Ensure we have sent and processed these release packets
 320    * before returning - we don't want to process any election
 321    * packets before dealing with the 1d release.
 322    */
 323
 324   retransmit_or_expire_response_records(time(NULL));
 325 }
 326
 327 /****************************************************************************
 328   Success in registering the WORKGROUP<1d> name.
 329   We are now *really* a local master browser.
 330   ****************************************************************************/
 331
 332 static void become_local_master_stage2(struct subnet_record *subrec,
 333                                         struct userdata_struct *userdata,
 334                                         struct nmb_name *registered_name,
 335                                         uint16 nb_flags,
 336                                         int ttl, struct in_addr registered_ip)
 337 {
 338   int i = 0;
 339   struct server_record *sl;
 340   struct work_record *work = find_workgroup_on_subnet( subrec, registered_name->name);
 341   struct server_record *servrec;
 342
 343   if(!work)
 344   {
 345     DEBUG(0,("become_local_master_stage2: Error - cannot find \
 346 workgroup %s on subnet %s\n", registered_name->name, subrec->subnet_name));
 347     return;
 348   }
 349
 350   if((servrec = find_server_in_workgroup( work, global_myname)) == NULL)
 351   {
 352     DEBUG(0,("become_local_master_stage2: Error - cannot find server %s \
 353 in workgroup %s on subnet %s\n",
 354        global_myname, registered_name->name, subrec->subnet_name));
 355     work->mst_state = lp_local_master() ? MST_POTENTIAL : MST_NONE;
 356     return;
 357   }
 358
 359   DEBUG(3,("become_local_master_stage2: registered as master browser for workgroup %s \
 360 on subnet %s\n", work->work_group, subrec->subnet_name));
 361
 362   work->mst_state = MST_BROWSER; /* registering WORKGROUP(1d) succeeded */
 363
 364   /* update our server status */
 365   servrec->serv.type |= SV_TYPE_MASTER_BROWSER;
 366   servrec->serv.type &= ~SV_TYPE_POTENTIAL_BROWSER;
 367
 368   /* Tell the namelist writer to write out a change. */
 369   subrec->work_changed = True;
 370
 371   /* Add this name to the workgroup as local master browser. */
 372   set_workgroup_local_master_browser_name( work, global_myname);
 373
 374   /* Count the number of servers we have on our list. If it's
 375      less than 10 (just a heuristic) request the servers
 376      to announce themselves.
 377    */
 378   for( sl = work->serverlist; sl != NULL; sl = sl->next)
 379     i++;
 380
 381   if (i < 10)
 382   {
 383     /* Ask all servers on our local net to announce to us. */
 384     broadcast_announce_request(subrec, work);
 385   }
 386
 387   /*
 388    * Now we are a local master on a broadcast subnet, we need to add
 389    * the WORKGROUP<1d> name to the unicast subnet so that we can answer
 390    * unicast requests sent to this name. We can create this name directly on
 391    * the unicast subnet as a WINS server always returns true when registering
 392    * this name, and discards the registration. We use the number of IP
 393    * addresses registered to this name as a reference count, as we
 394    * remove this broadcast subnet IP address from it when we stop becoming a local
 395    * master browser for this broadcast subnet.
 396    */
 397
 398   insert_permanent_name_into_unicast( subrec, registered_name, nb_flags);
 399
 400   /* Reset the announce master browser timer so that we try and tell a domain
 401      master browser as soon as possible that we are a local master browser. */
 402   reset_announce_timer();
 403
 404   if( DEBUGLVL( 0 ) )
 405   {
 406     dbgtext( "*****\n\n" );
 407     dbgtext( "Samba name server %s ", global_myname );
 408     dbgtext( "is now a local master browser " );
 409     dbgtext( "for workgroup %s ", work->work_group );
 410     dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
 411   }
 412
 413 }
 414
 415 /****************************************************************************
 416   Failed to register the WORKGROUP<1d> name.
 417   ****************************************************************************/
 418 static void become_local_master_fail2(struct subnet_record *subrec,
 419                                       struct response_record *rrec,
 420                                       struct nmb_name *fail_name)
 421 {
 422   struct work_record *work = find_workgroup_on_subnet( subrec, fail_name->name);
 423
 424   DEBUG(0,("become_local_master_fail2: failed to register name %s on subnet %s. \
 425 Failed to become a local master browser.\n", nmb_namestr(fail_name), subrec->subnet_name));
 426
 427   if(!work)
 428   {
 429     DEBUG(0,("become_local_master_fail2: Error - cannot find \
 430 workgroup %s on subnet %s\n", fail_name->name, subrec->subnet_name));
 431     return;
 432   }
 433
 434   /* Roll back all the way by calling unbecome_local_master_browser(). */
 435   unbecome_local_master_browser(subrec, work, False);
 436 }
 437
 438 /****************************************************************************
 439   Success in registering the MSBROWSE name.
 440   ****************************************************************************/
 441
 442 static void become_local_master_stage1(struct subnet_record *subrec,
 443                                         struct userdata_struct *userdata,
 444                                         struct nmb_name *registered_name,
 445                                         uint16 nb_flags,
 446                                         int ttl, struct in_addr registered_ip)
 447 {
 448   char *work_name = userdata->data;
 449   struct work_record *work = find_workgroup_on_subnet( subrec, work_name);
 450
 451   if(!work)
 452   {
 453     DEBUG(0,("become_local_master_stage1: Error - cannot find \
 454 workgroup %s on subnet %s\n", work_name, subrec->subnet_name));
 455     return;
 456   }
 457
 458   DEBUG(3,("become_local_master_stage1: go to stage 2: register the %s<1d> name.\n",
 459             work->work_group));
 460
 461   work->mst_state = MST_MSB; /* Registering MSBROWSE was successful. */
 462
 463   /*
 464    * We registered the MSBROWSE name on a broadcast subnet, now need to add
 465    * the MSBROWSE name to the unicast subnet so that we can answer
 466    * unicast requests sent to this name. We create this name directly on
 467    * the unicast subnet.
 468    */
 469
 470   insert_permanent_name_into_unicast( subrec, registered_name, nb_flags);
 471
 472   /* Attempt to register the WORKGROUP<1d> name. */
 473   register_name(subrec, work->work_group,0x1d,samba_nb_type,
 474                 become_local_master_stage2,
 475                 become_local_master_fail2,
 476                 NULL);
 477 }
 478
 479 /****************************************************************************
 480   Failed to register the MSBROWSE name.
 481   ****************************************************************************/
 482
 483 static void become_local_master_fail1(struct subnet_record *subrec,
 484                                       struct response_record *rrec,
 485                                       struct nmb_name *fail_name)
 486 {
 487   char *work_name = rrec->userdata->data;
 488   struct work_record *work = find_workgroup_on_subnet(subrec, work_name);
 489
 490   if(!work)
 491   {
 492     DEBUG(0,("become_local_master_fail1: Error - cannot find \
 493 workgroup %s on subnet %s\n", work_name, subrec->subnet_name));
 494     return;
 495   }
 496
 497   if(find_server_in_workgroup(work, global_myname) == NULL)
 498   {
 499     DEBUG(0,("become_local_master_fail1: Error - cannot find server %s \
 500 in workgroup %s on subnet %s\n",
 501        global_myname, work->work_group, subrec->subnet_name));
 502     return;
 503   }
 504
 505   reset_workgroup_state( subrec, work->work_group, False );
 506
 507   DEBUG(0,("become_local_master_fail1: Failed to become a local master browser for \
 508 workgroup %s on subnet %s. Couldn't register name %s.\n",
 509        work->work_group, subrec->subnet_name, nmb_namestr(fail_name)));
 510 }
 511
 512 /******************************************************************
 513   Become the local master browser on a subnet.
 514   This gets called if we win an election on this subnet.
 515
 516   Stage 1: mst_state was MST_POTENTIAL - go to MST_BACK register ^1^2__MSBROWSE__^2^1.
 517   Stage 2: mst_state was MST_BACKUP  - go to MST_MSB  and register WORKGROUP<1d>.
 518   Stage 3: mst_state was MST_MSB  - go to MST_BROWSER.
 519 ******************************************************************/
 520
 521 void become_local_master_browser(struct subnet_record *subrec, struct work_record *work)
 522 {
 523   struct userdata_struct *userdata;
 524   int size = sizeof(struct userdata_struct) + sizeof(fstring) + 1;
 525
 526   /* Sanity check. */
 527   if (!lp_local_master())
 528   {
 529     DEBUG(0,("become_local_master_browser: Samba not configured as a local master browser.\n"));
 530     return;
 531   }
 532
 533   if(!AM_POTENTIAL_MASTER_BROWSER(work))
 534   {
 535     DEBUG(2,("become_local_master_browser: Awaiting potential browser state. Current state is %d\n",
 536               work->mst_state ));
 537     return;
 538   }
 539
 540   if(find_server_in_workgroup( work, global_myname) == NULL)
 541   {
 542     DEBUG(0,("become_local_master_browser: Error - cannot find server %s \
 543 in workgroup %s on subnet %s\n",
 544        global_myname, work->work_group, subrec->subnet_name));
 545     return;
 546   }
 547
 548   DEBUG(2,("become_local_master_browser: Starting to become a master browser for workgroup \
 549 %s on subnet %s\n", work->work_group, subrec->subnet_name));
 550
 551   DEBUG(3,("become_local_master_browser: first stage - attempt to register ^1^2__MSBROWSE__^2^1\n"));
 552   work->mst_state = MST_BACKUP; /* an election win was successful */
 553
 554   work->ElectionCriterion |= 0x5;
 555
 556   /* Tell the namelist writer to write out a change. */
 557   subrec->work_changed = True;
 558
 559   /* Setup the userdata_struct. */
 560   if((userdata = (struct userdata_struct *)malloc(size)) == NULL)
 561   {
 562     DEBUG(0,("become_local_master_browser: malloc fail.\n"));
 563     return;
 564   }
 565
 566   userdata->copy_fn = NULL;
 567   userdata->free_fn = NULL;
 568   userdata->userdata_len = strlen(work->work_group)+1;
 569   pstrcpy(userdata->data, work->work_group);
 570
 571   /* Register the special browser group name. */
 572   register_name(subrec, MSBROWSE, 0x01, samba_nb_type|NB_GROUP,
 573                 become_local_master_stage1,
 574                 become_local_master_fail1,
 575                 userdata);
 576
 577   zero_free(userdata, size);
 578 }
 579
 580 /***************************************************************
 581  Utility function to set the local master browser name. Does
 582  some sanity checking as old versions of Samba seem to sometimes
 583  say that the master browser name for a workgroup is the same
 584  as the workgroup name.
 585 ****************************************************************/
 586
 587 void set_workgroup_local_master_browser_name( struct work_record *work, char *newname)
 588 {
 589   DEBUG(5,("set_workgroup_local_master_browser_name: setting local master name to '%s' \
 590 for workgroup %s.\n", newname, work->work_group ));
 591
 592 #if 0
 593   /*
 594    * Apparently some sites use the workgroup name as the local
 595    * master browser name. Arrrrggghhhhh ! (JRA).
 596    */
 597   if(strequal( work->work_group, newname))
 598   {
 599     DEBUG(5, ("set_workgroup_local_master_browser_name: Refusing to set \
 600 local_master_browser_name for workgroup %s to workgroup name.\n",
 601          work->work_group ));
 602     return;
 603   }
 604 #endif
 605
 606   StrnCpy(work->local_master_browser_name, newname,
 607             sizeof(work->local_master_browser_name)-1);
 608 }