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