source/nameelect.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    NBT netbios routines and daemon - version 2
   5    Copyright (C) Andrew Tridgell 1994-1997
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21    Module name: nameelect.c
  22
  23    Revision History:
  24
  25    14 jan 96: lkcl@pires.co.uk
  26    added multiple workgroup domain master support
  27
  28    04 jul 96: lkcl@pires.co.uk
  29    added system to become a master browser by stages.
  30
  31
  32 */
  33
  34 #include "includes.h"
  35
  36 extern int ClientNMB;
  37 extern int ClientDGRAM;
  38
  39 extern int DEBUGLEVEL;
  40 extern pstring scope;
  41
  42 extern pstring myname;
  43 extern fstring myworkgroup;
  44 extern struct in_addr ipzero;
  45 extern struct in_addr wins_ip;
  46
  47 /* here are my election parameters */
  48
  49 extern time_t StartupTime;
  50
  51 extern struct subnet_record *subnetlist;
  52
  53 extern uint16 nb_type; /* samba's NetBIOS name type */
  54
  55
  56 /*******************************************************************
  57   occasionally check to see if the master browser is around
  58   ******************************************************************/
  59 void check_master_browser(time_t t)
  60 {
  61   static time_t lastrun=0;
  62   struct subnet_record *d;
  63
  64   if (!lastrun) lastrun = t;
  65   if (t < lastrun + CHECK_TIME_MST_BROWSE * 60) return;
  66
  67   lastrun = t;
  68
  69   dump_workgroups();
  70
  71   for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_EXCLUDING_WINS(d))
  72   {
  73     struct work_record *work;
  74
  75     for (work = d->workgrouplist; work; work = work->next)
  76     {
  77       if (strequal(work->work_group, myworkgroup) && !AM_MASTER(work))
  78       {
  79         if (lp_local_master())
  80         {
  81           /* potential master browser - not a master browser.  force
  82              becoming a master browser, hence the log message.
  83            */
  84
  85           DEBUG(2,("%s potential master for %s %s - force election\n",
  86                    timestring(), work->work_group,
  87                    inet_ntoa(d->bcast_ip)));
  88
  89           browser_gone(work->work_group, d->bcast_ip);
  90         }
  91         else
  92         {
  93           /* if we are not the browse master of a workgroup,
  94              and we can't find a browser on the subnet, do
  95              something about it.
  96            */
  97
  98           queue_netbios_packet(d,ClientNMB,NMB_QUERY,NAME_QUERY_MST_CHK,
  99                     work->work_group,0x1d,0,0,0,NULL,NULL,
 100                     True,False,d->bcast_ip,d->bcast_ip);
 101         }
 102       }
 103     }
 104   }
 105 }
 106
 107
 108 /*******************************************************************
 109   what to do if a master browser DOESN't exist.
 110
 111   option 1: force an election, and participate in it
 112   option 2: force an election, and let everyone else participate.
 113
 114   ******************************************************************/
 115 void browser_gone(char *work_name, struct in_addr ip)
 116 {
 117   struct subnet_record *d = find_subnet(ip);
 118   struct work_record *work = find_workgroupstruct(d, work_name, False);
 119
 120   /* i don't know about this workgroup, therefore i don't care */
 121   if (!work || !d) return;
 122
 123   /* don't do election stuff on the WINS subnet */
 124   if (ip_equal(d->bcast_ip,wins_ip))
 125     return;
 126
 127   if (strequal(work->work_group, myworkgroup))
 128   {
 129
 130     if (lp_local_master())
 131     {
 132       /* we have discovered that there is no local master
 133          browser, and we are configured to initiate
 134          an election under exactly such circumstances.
 135        */
 136       DEBUG(2,("Forcing election on %s %s\n",
 137                work->work_group,inet_ntoa(d->bcast_ip)));
 138
 139       /* we can attempt to become master browser */
 140       work->needelection = True;
 141     }
 142     else
 143     {
 144       /* we need to force an election, because we are configured
 145          not to _become_ the local master, but we still _need_ one,
 146          having detected that one doesn't exist.
 147        */
 148
 149       /* local interfaces: force an election */
 150       send_election(d, work->work_group, 0, 0, myname);
 151
 152       /* only removes workgroup completely on a local interface
 153          persistent lmhosts entries on a local interface _will_ be removed).
 154        */
 155       remove_workgroup(d, work,True);
 156       add_workgroup_to_subnet(d, work->work_group);
 157     }
 158   }
 159 }
 160
 161
 162 /****************************************************************************
 163   send an election packet
 164   **************************************************************************/
 165 void send_election(struct subnet_record *d, char *group,uint32 criterion,
 166                    int timeup,char *name)
 167 {
 168   pstring outbuf;
 169   char *p;
 170
 171   if (!d) return;
 172
 173   DEBUG(2,("Sending election to %s for workgroup %s\n",
 174            inet_ntoa(d->bcast_ip),group));
 175
 176   bzero(outbuf,sizeof(outbuf));
 177   p = outbuf;
 178   CVAL(p,0) = ANN_Election; /* election */
 179   p++;
 180
 181   CVAL(p,0) = (criterion == 0 && timeup == 0) ? 0 : ELECTION_VERSION;
 182   SIVAL(p,1,criterion);
 183   SIVAL(p,5,timeup*1000); /* ms - despite the spec */
 184   p += 13;
 185   strcpy(p,name);
 186   strupper(p);
 187   p = skip_string(p,1);
 188
 189   send_mailslot_reply(False,BROWSE_MAILSLOT,ClientDGRAM,
 190               outbuf,PTR_DIFF(p,outbuf),
 191                       name,group,0,0x1e,d->bcast_ip,*iface_ip(d->bcast_ip));
 192 }
 193
 194
 195 /****************************************************************************
 196   un-register a SELF name that got rejected.
 197
 198   if this name happens to be rejected when samba is in the process
 199   of becoming a master browser (registering __MSBROWSE__, WORKGROUP(1d)
 200   or WORKGROUP(1b)) then we must stop being a master browser. sad.
 201
 202   **************************************************************************/
 203 void name_unregister_work(struct subnet_record *d, char *name, int name_type)
 204 {
 205     struct work_record *work;
 206     int remove_type_local  = 0;
 207     int remove_type_domain = 0;
 208     int remove_type_logon  = 0;
 209
 210     remove_netbios_name(d,name,name_type,SELF,ipzero);
 211
 212     if (!(work = find_workgroupstruct(d, name, False))) return;
 213
 214     /* work out what to unbecome, from the name type being removed */
 215
 216     if (ms_browser_name(name, name_type))
 217     {
 218       remove_type_local |= SV_TYPE_MASTER_BROWSER;
 219     }
 220     if (AM_MASTER(work) && strequal(name, myworkgroup) && name_type == 0x1d)
 221     {
 222       remove_type_local |= SV_TYPE_MASTER_BROWSER;
 223     }
 224     if (AM_DOMMST(work) && strequal(name, myworkgroup) && name_type == 0x1b)
 225     {
 226       remove_type_domain |= SV_TYPE_DOMAIN_MASTER;
 227     }
 228     if (AM_DOMMEM(work) && strequal(name, myworkgroup) && name_type == 0x1c)
 229     {
 230       remove_type_logon|= SV_TYPE_DOMAIN_MEMBER;
 231     }
 232
 233     if (remove_type_local ) unbecome_local_master (d, work, remove_type_local );
 234     if (remove_type_domain) unbecome_domain_master(d, work, remove_type_domain);
 235     if (remove_type_logon ) unbecome_logon_server (d, work, remove_type_logon );
 236 }
 237
 238
 239 /****************************************************************************
 240   registers a name.
 241
 242   if the name being added is a SELF name, we must additionally check
 243   whether to proceed to the next stage in samba becoming a master browser.
 244
 245   **************************************************************************/
 246 void name_register_work(struct subnet_record *d, char *name, int name_type,
 247                                 int nb_flags, time_t ttl, struct in_addr ip, BOOL bcast)
 248 {
 249   enum name_source source = (ismyip(ip) || ip_equal(ip, ipzero)) ?
 250                                   SELF : REGISTER;
 251
 252   if (source == SELF)
 253     {
 254       struct work_record *work = find_workgroupstruct(d,
 255                                   myworkgroup, False);
 256
 257       add_netbios_entry(d,name,name_type,nb_flags,ttl,source,ip,True,!bcast);
 258
 259       if (work)
 260       {
 261         int add_type_local  = False;
 262         int add_type_domain = False;
 263         int add_type_logon  = False;
 264
 265         DEBUG(4,("checking next stage: name_register_work %s\n", name));
 266
 267         /* work out what to become, from the name type being added */
 268
 269         if (ms_browser_name(name, name_type))
 270         {
 271           add_type_local = True;
 272         }
 273         if (strequal(name, myworkgroup) && name_type == 0x1d)
 274         {
 275           add_type_local = True;
 276         }
 277         if (strequal(name, myworkgroup) && name_type == 0x1b)
 278         {
 279           add_type_domain = True;
 280         }
 281         if (strequal(name, myworkgroup) && name_type == 0x1c)
 282         {
 283           add_type_logon = True;
 284         }
 285
 286         if (add_type_local ) become_local_master (d, work);
 287         if (add_type_domain) become_domain_master(d, work);
 288         if (add_type_logon ) become_logon_server (d, work);
 289       }
 290     }
 291 }
 292
 293
 294 /*******************************************************************
 295   become the local master browser.
 296
 297   this is done in stages. note that this could take a while,
 298   particularly on a broadcast subnet, as we have to wait for
 299   the implicit registration of each name to be accepted.
 300
 301   as each name is successfully registered, become_local_master() is
 302   called again, in order to initiate the next stage. see
 303   dead_netbios_entry() - deals with implicit name registration
 304   and response_name_reg() - deals with explicit registration
 305   with a WINS server.
 306
 307   stage 1: was MST_POTENTIAL - go to MST_POTENTIAL and register ^1^2__MSBROWSE__^2^1.
 308   stage 2: was MST_BACK  - go to MST_MSB  and register WORKGROUP(0x1d)
 309   stage 3: was MST_MSB  - go to MST_BROWSER and stay there
 310
 311   XXXX note: this code still does not cope with the distinction
 312   between different types of nodes, particularly between M and P
 313   nodes. that comes later.
 314
 315   ******************************************************************/
 316 void become_local_master(struct subnet_record *d, struct work_record *work)
 317 {
 318   /* domain type must be limited to domain enum + server type. it must
 319      not have SV_TYPE_SERVER or anything else with SERVER in it, else
 320      clients get confused and start thinking this entry is a server
 321      not a workgroup
 322    */
 323   uint32 domain_type = SV_TYPE_DOMAIN_ENUM|SV_TYPE_NT;
 324
 325   if (!work || !d)
 326     return;
 327
 328   if (!lp_local_master())
 329   {
 330     DEBUG(0,("Samba not configured as a local master browser.\n"));
 331     return;
 332   }
 333
 334   DEBUG(2,("Becoming master for %s %s (currently at stage %d)\n",
 335            work->work_group,inet_ntoa(d->bcast_ip),work->mst_state));
 336
 337   switch (work->mst_state)
 338   {
 339     case MST_POTENTIAL: /* while we were nothing but a server... */
 340     {
 341       DEBUG(3,("go to first stage: register ^1^2__MSBROWSE__^2^1\n"));
 342       work->mst_state = MST_BACK; /* an election win was successful */
 343
 344       work->ElectionCriterion |= 0x5;
 345
 346       /* update our server status */
 347       work->ServerType &= ~SV_TYPE_POTENTIAL_BROWSER;
 348       add_server_entry(d,work,myname,work->ServerType|SV_TYPE_LOCAL_LIST_ONLY,
 349                                 0,lp_serverstring(),True);
 350
 351       /* add special browser name */
 352       add_my_name_entry(d,MSBROWSE,0x01,nb_type|NB_ACTIVE|NB_GROUP,False);
 353
 354       /* DON'T do anything else after calling add_my_name_entry() */
 355       break;
 356     }
 357
 358     case MST_BACK: /* while nothing had happened except we won an election... */
 359     {
 360       DEBUG(3,("go to second stage: register as master browser\n"));
 361       work->mst_state = MST_MSB; /* registering MSBROWSE was successful */
 362
 363       /* add server entry on successful registration of MSBROWSE */
 364       add_server_entry(d,work,work->work_group,domain_type|SV_TYPE_LOCAL_LIST_ONLY,
 365                                 0,myname,True);
 366
 367       /* add master name */
 368       add_my_name_entry(d,work->work_group,0x1d,nb_type|NB_ACTIVE,False);
 369
 370       /* DON'T do anything else after calling add_my_name_entry() */
 371       break;
 372     }
 373
 374     case MST_MSB: /* while we were still only registered MSBROWSE state... */
 375     {
 376       int i = 0;
 377       struct server_record *sl;
 378
 379       DEBUG(3,("2nd stage complete: registered as master browser for workgroup %s \
 380 on subnet %s\n", work->work_group, inet_ntoa(d->bcast_ip)));
 381       work->mst_state = MST_BROWSER; /* registering WORKGROUP(1d) succeeded */
 382
 383       /* update our server status */
 384       work->ServerType |= SV_TYPE_MASTER_BROWSER;
 385
 386       DEBUG(3,("become_local_master: updating our server %s to type %x\n",
 387                 myname, work->ServerType));
 388
 389       add_server_entry(d,work,myname,work->ServerType|SV_TYPE_LOCAL_LIST_ONLY,
 390                                 0,lp_serverstring(),True);
 391
 392       /* Count the number of servers we have on our list. If it's
 393          less than 10 (just a heuristic) request the servers
 394          to announce themselves.
 395        */
 396       for( sl = work->serverlist; sl != NULL; sl = sl->next)
 397         i++;
 398
 399       if (i < 10)
 400       {
 401         /* ask all servers on our local net to announce to us */
 402         announce_request(work, d->bcast_ip);
 403       }
 404
 405       /* Reset the announce master timer so that we do an announce as soon as possible
 406          now we are a master. */
 407       reset_announce_timer();
 408
 409       DEBUG(0,("Samba is now a local master browser for workgroup %s on subnet %s\n",
 410                 work->work_group, inet_ntoa(d->bcast_ip)));
 411
 412       break;
 413     }
 414
 415     case MST_BROWSER:
 416     {
 417       /* don't have to do anything: just report success */
 418       DEBUG(3,("3rd stage: become master browser!\n"));
 419       break;
 420     }
 421   }
 422 }
 423
 424
 425 /*******************************************************************
 426   become the domain master browser.
 427
 428   this is done in stages. note that this could take a while,
 429   particularly on a broadcast subnet, as we have to wait for
 430   the implicit registration of each name to be accepted.
 431
 432   as each name is successfully registered, become_domain_master() is
 433   called again, in order to initiate the next stage. see
 434   dead_netbios_entry() - deals with implicit name registration
 435   and response_name_reg() - deals with explicit registration
 436   with a WINS server.
 437
 438   stage 1: was DOMAIN_NONE - go to DOMAIN_MST
 439
 440   XXXX note: this code still does not cope with the distinction
 441   between different types of nodes, particularly between M and P
 442   nodes. that comes later.
 443
 444   ******************************************************************/
 445 void become_domain_master(struct subnet_record *d, struct work_record *work)
 446 {
 447   /* domain type must be limited to domain enum + server type. it must
 448      not have SV_TYPE_SERVER or anything else with SERVER in it, else
 449      clients get confused and start thinking this entry is a server
 450      not a workgroup
 451    */
 452
 453   if (!work || !d) return;
 454
 455   if (!lp_domain_master())
 456   {
 457     DEBUG(0,("Samba not configured as a domain master browser.\n"));
 458     return;
 459   }
 460
 461   DEBUG(2,("Becoming domain master for %s %s (currently at stage %d)\n",
 462         work->work_group,inet_ntoa(d->bcast_ip),work->dom_state));
 463
 464   switch (work->dom_state)
 465   {
 466     case DOMAIN_NONE: /* while we were nothing but a server... */
 467     {
 468       DEBUG(3,("become_domain_master: go to first stage: register <1b> name\n"));
 469       work->dom_state = DOMAIN_WAIT;
 470
 471       /* Registering the DOMAIN<1b> name is very tricky. We need to
 472          do this on all our subnets, but don't want to bradcast it
 473          on locally connected subnets (WinNT doesn't do this). Also,
 474          previous versions of Samba screw up royally when we do this.
 475          We need to register it immediatly on our local subnet, but
 476          also actually check with the WINS server if it exists. If the name
 477          has already been claimed by someone else in the WINS server
 478          then we need to back out all our local registrations and
 479          fail. Thus we only directly enter the name on local subnets,
 480          on the WINS subnet we actually check...
 481       */
 482       /* XXXX the 0x1b is domain master browser name */
 483       if(d == wins_subnet)
 484         add_my_name_entry(d, work->work_group,0x1b,nb_type|NB_ACTIVE,False);
 485       else
 486         add_my_name_entry(d, work->work_group,0x1b,nb_type|NB_ACTIVE,True);
 487
 488       /* DON'T do anything else after calling add_my_name_entry() */
 489       break;
 490     }
 491
 492     case DOMAIN_WAIT:
 493     {
 494       work->dom_state = DOMAIN_MST; /* ... become domain master */
 495       DEBUG(3,("become_domain_master: first stage - register as domain member\n"));
 496
 497       /* update our server status */
 498       work->ServerType |= SV_TYPE_NT|SV_TYPE_DOMAIN_MASTER;
 499       add_server_entry(d,work,myname,work->ServerType|SV_TYPE_LOCAL_LIST_ONLY,
 500                                         0, lp_serverstring(),True);
 501
 502       DEBUG(0,("Samba is now a domain master browser for workgroup %s on subnet %s\n",
 503                 work->work_group, inet_ntoa(d->bcast_ip)));
 504
 505       break;
 506     }
 507
 508     case DOMAIN_MST:
 509     {
 510       /* don't have to do anything: just report success */
 511       DEBUG(3,("domain second stage: there isn't one!\n"));
 512       break;
 513     }
 514   }
 515 }
 516
 517
 518 /*******************************************************************
 519   become a logon server.
 520   ******************************************************************/
 521 void become_logon_server(struct subnet_record *d, struct work_record *work)
 522 {
 523   if (!work || !d) return;
 524
 525   if (!lp_domain_logons())
 526   {
 527     DEBUG(0,("samba not configured as a logon master.\n"));
 528     return;
 529   }
 530
 531   DEBUG(2,("Becoming logon server for %s %s (currently at stage %d)\n",
 532         work->work_group,inet_ntoa(d->bcast_ip),work->log_state));
 533
 534   switch (work->log_state)
 535   {
 536     case LOGON_NONE: /* while we were nothing but a server... */
 537     {
 538       DEBUG(3,("go to first stage: register <1c> name\n"));
 539             work->log_state = LOGON_WAIT;
 540
 541      /* XXXX the 0x1c is apparently something to do with domain logons */
 542      add_my_name_entry(d, myworkgroup,0x1c,nb_type|NB_ACTIVE|NB_GROUP,False);
 543
 544       /* DON'T do anything else after calling add_my_name_entry() */
 545       break;
 546     }
 547
 548     case LOGON_WAIT:
 549     {
 550       work->log_state = LOGON_SRV; /* ... become logon server */
 551       DEBUG(3,("logon second stage: register \n"));
 552
 553       /* update our server status */
 554       work->ServerType |= SV_TYPE_NT|SV_TYPE_DOMAIN_MEMBER;
 555       add_server_entry(d,work,myname,work->ServerType|SV_TYPE_LOCAL_LIST_ONLY
 556                                         ,0, lp_serverstring(),True);
 557
 558       /* DON'T do anything else after calling add_my_name_entry() */
 559       break;
 560     }
 561
 562     case LOGON_SRV:
 563     {
 564       DEBUG(3,("logon third stage: there isn't one!\n"));
 565       break;
 566     }
 567   }
 568 }
 569
 570
 571 /*******************************************************************
 572   unbecome the local master browser. initates removal of necessary netbios
 573   names, and tells the world that we are no longer a master browser.
 574
 575   XXXX this _should_ be used to demote to a backup master browser, without
 576   going straight to non-master browser.  another time.
 577
 578   ******************************************************************/
 579 void unbecome_local_master(struct subnet_record *d, struct work_record *work,
 580                                 int remove_type)
 581 {
 582   int new_server_type = work->ServerType;
 583
 584   /* can only remove master types with this function */
 585   remove_type &= SV_TYPE_MASTER_BROWSER;
 586
 587   new_server_type &= ~remove_type;
 588
 589   if (remove_type)
 590   {
 591     DEBUG(2,("Becoming local non-master for %s\n",work->work_group));
 592
 593     /* no longer a master browser of any sort */
 594
 595     work->ServerType |= SV_TYPE_POTENTIAL_BROWSER;
 596     work->ElectionCriterion &= ~0x4;
 597     work->mst_state = MST_POTENTIAL;
 598
 599         /* announce ourselves as no longer active as a master browser. */
 600     announce_server(d, work, work->work_group, myname, 0, 0);
 601     remove_name_entry(d,MSBROWSE        ,0x01,False);
 602     remove_name_entry(d,work->work_group,0x1d,False);
 603   }
 604 }
 605
 606
 607 /*******************************************************************
 608   unbecome the domain master browser. initates removal of necessary netbios
 609   names, and tells the world that we are no longer a domain browser.
 610   ******************************************************************/
 611 void unbecome_domain_master(struct subnet_record *d, struct work_record *work,
 612                                 int remove_type)
 613 {
 614   int new_server_type = work->ServerType;
 615
 616   DEBUG(2,("Becoming domain non-master for %s\n",work->work_group));
 617
 618   /* can only remove master or domain types with this function */
 619   remove_type &= SV_TYPE_DOMAIN_MASTER;
 620
 621   new_server_type &= ~remove_type;
 622
 623   if (remove_type)
 624   {
 625     /* no longer a domain master browser of any sort */
 626
 627     work->dom_state = DOMAIN_NONE;
 628
 629     /* announce ourselves as no longer active as a master browser on
 630        all our local subnets. */
 631     for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_EXCLUDING_WINS(d))
 632     {
 633       work = find_workgroupstruct(d, myworkgroup, False);
 634
 635       announce_server(d, work, work->work_group, myname, 0, 0);
 636       /* Remove the name entry without any NetBIOS traffic as that's
 637          how it was registered. */
 638       remove_name_entry(d,work->work_group,0x1b,True);
 639     }
 640   }
 641 }
 642
 643
 644 /*******************************************************************
 645   unbecome the logon server. initates removal of necessary netbios
 646   names, and tells the world that we are no longer a logon server.
 647   ******************************************************************/
 648 void unbecome_logon_server(struct subnet_record *d, struct work_record *work,
 649                                 int remove_type)
 650 {
 651   int new_server_type = work->ServerType;
 652
 653   DEBUG(2,("Becoming logon non-server for %s\n",work->work_group));
 654
 655   /* can only remove master or domain types with this function */
 656   remove_type &= SV_TYPE_DOMAIN_MEMBER;
 657
 658   new_server_type &= ~remove_type;
 659
 660   if (remove_type)
 661   {
 662     /* no longer a master browser of any sort */
 663
 664     work->log_state = LOGON_NONE;
 665
 666         /* announce ourselves as no longer active as a master browser. */
 667     announce_server(d, work, work->work_group, myname, 0, 0);
 668     remove_name_entry(d,work->work_group,0x1c,False);
 669   }
 670 }
 671
 672
 673 /*******************************************************************
 674   run the election
 675   ******************************************************************/
 676 void run_elections(time_t t)
 677 {
 678   static time_t lastime = 0;
 679
 680   struct subnet_record *d;
 681
 682   /* send election packets once a second */
 683   if (lastime && t-lastime <= 0) return;
 684
 685   lastime = t;
 686
 687   for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_EXCLUDING_WINS(d))
 688   {
 689     struct work_record *work;
 690
 691     for (work = d->workgrouplist; work; work = work->next)
 692         {
 693           if (work->RunningElection)
 694           {
 695             send_election(d,work->work_group, work->ElectionCriterion,
 696                             t-StartupTime,myname);
 697
 698             if (work->ElectionCount++ >= 4)
 699                 {
 700                   /* I won! now what :-) */
 701                   DEBUG(2,(">>> Won election on %s %s <<<\n",
 702                            work->work_group,inet_ntoa(d->bcast_ip)));
 703
 704                   work->RunningElection = False;
 705                   work->mst_state = MST_POTENTIAL;
 706
 707                   become_local_master(d, work);
 708                 }
 709           }
 710         }
 711   }
 712 }
 713
 714
 715 /*******************************************************************
 716   work out if I win an election
 717   ******************************************************************/
 718 static BOOL win_election(struct work_record *work,int version,uint32 criterion,
 719                          int timeup,char *name)
 720 {
 721   int mytimeup = time(NULL) - StartupTime;
 722   uint32 mycriterion = work->ElectionCriterion;
 723
 724   /* If local master is false then never win
 725      in election broadcasts. */
 726   if(!lp_local_master())
 727   {
 728     DEBUG(3,("win_election: Losing election as local master == False\n"));
 729     return False;
 730   }
 731
 732   DEBUG(4,("election comparison: %x:%x %x:%x %d:%d %s:%s\n",
 733            version,ELECTION_VERSION,
 734            criterion,mycriterion,
 735            timeup,mytimeup,
 736            name,myname));
 737
 738   if (version > ELECTION_VERSION) return(False);
 739   if (version < ELECTION_VERSION) return(True);
 740
 741   if (criterion > mycriterion) return(False);
 742   if (criterion < mycriterion) return(True);
 743
 744   if (timeup > mytimeup) return(False);
 745   if (timeup < mytimeup) return(True);
 746
 747   if (strcasecmp(myname,name) > 0) return(False);
 748
 749   return(True);
 750 }
 751
 752
 753 /*******************************************************************
 754   process a election packet
 755
 756   An election dynamically decides who will be the master.
 757   ******************************************************************/
 758 void process_election(struct packet_struct *p,char *buf)
 759 {
 760         struct dgram_packet *dgram = &p->packet.dgram;
 761         struct in_addr ip = dgram->header.source_ip;
 762         struct subnet_record *d = find_subnet(ip);
 763         int version = CVAL(buf,0);
 764         uint32 criterion = IVAL(buf,1);
 765         int timeup = IVAL(buf,5)/1000;
 766         char *name = buf+13;
 767         struct work_record *work;
 768
 769         if (!d) return;
 770
 771         if (ip_equal(d->bcast_ip,wins_ip))
 772         {
 773                 DEBUG(3,("Unexpected election request from %s %s on WINS net\n",
 774                           name, inet_ntoa(p->ip)));
 775                 return;
 776         }
 777
 778         name[15] = 0;
 779
 780         DEBUG(3,("Election request from %s %s vers=%d criterion=%08x timeup=%d\n",
 781                   name,inet_ntoa(p->ip),version,criterion,timeup));
 782
 783         if (same_context(dgram)) return;
 784
 785         for (work = d->workgrouplist; work; work = work->next)
 786         {
 787                 if (!strequal(work->work_group, myworkgroup))
 788                 continue;
 789
 790                 if (win_election(work, version,criterion,timeup,name))
 791                 {
 792                         if (!work->RunningElection)
 793                         {
 794                                 work->needelection = True;
 795                                 work->ElectionCount=0;
 796                                 work->mst_state = MST_POTENTIAL;
 797                         }
 798                 }
 799                 else
 800                 {
 801                         work->needelection = False;
 802
 803                         if (work->RunningElection || AM_MASTER(work))
 804                         {
 805                                 work->RunningElection = False;
 806                                 DEBUG(3,(">>> Lost election on %s %s <<<\n",
 807                                                   work->work_group,inet_ntoa(d->bcast_ip)));
 808                                 if (AM_MASTER(work))
 809                                 {
 810                                         unbecome_local_master(d, work, SV_TYPE_MASTER_BROWSER);
 811                                 }
 812                         }
 813                 }
 814         }
 815 }
 816
 817
 818 /****************************************************************************
 819   checks whether a browser election is to be run on any workgroup
 820
 821   this function really ought to return the time between election
 822   packets (which depends on whether samba intends to be a domain
 823   master or a master browser) in milliseconds.
 824
 825   ***************************************************************************/
 826 BOOL check_elections(void)
 827 {
 828   struct subnet_record *d;
 829   BOOL run_any_election = False;
 830
 831   for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_EXCLUDING_WINS(d))
 832     {
 833       struct work_record *work;
 834       for (work = d->workgrouplist; work; work = work->next)
 835         {
 836           run_any_election |= work->RunningElection;
 837
 838           if (work->needelection && !work->RunningElection)
 839             {
 840               DEBUG(3,(">>> Starting election on %s %s <<<\n",
 841                        work->work_group,inet_ntoa(d->bcast_ip)));
 842               work->ElectionCount = 0;
 843               work->RunningElection = True;
 844               work->needelection = False;
 845             }
 846         }
 847     }
 848   return run_any_election;
 849 }
 850