summaryrefslogtreecommitdiff
path: root/source3/nameelect.c
blob: 1c4f8e63900728b2d80c248fa527338e5d7be65a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   NBT netbios routines and daemon - version 2
   Copyright (C) Andrew Tridgell 1994-1996
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   
   Module name: nameelect.c

   Revision History:

   14 jan 96: lkcl@pires.co.uk
   added multiple workgroup domain master support

   04 jul 96: lkcl@pires.co.uk
   added system to become a master browser by stages.


*/

#include "includes.h"

extern int ClientNMB;
extern int ClientDGRAM;

extern int DEBUGLEVEL;
extern pstring scope;

extern pstring myname;
extern struct in_addr ipzero;
extern struct in_addr ipgrp;

/* here are my election parameters */

extern time_t StartupTime;

extern struct subnet_record *subnetlist;

extern uint16 nb_type; /* samba's NetBIOS name type */

/*******************************************************************
  occasionally check to see if the master browser is around
  ******************************************************************/
void check_master_browser(time_t t)
{
  static time_t lastrun=0;
  struct subnet_record *d;

  if (!lastrun) lastrun = t;
  if (t < lastrun + CHECK_TIME_MST_BROWSE * 60)
    return;
  lastrun = t;

  dump_workgroups();

  for (d = subnetlist; d; d = d->next)
    {
      struct work_record *work;

      for (work = d->workgrouplist; work; work = work->next)
	{
	  /* if we are not the browse master of a workgroup, and we can't
	     find a browser on the subnet, do something about it. */

	  if (!AM_MASTER(work))
	    {
	      queue_netbios_packet(d,ClientNMB,NMB_QUERY,NAME_QUERY_MST_CHK,
				   work->work_group,0x1d,0,0,0,NULL,NULL,
				   True,False,d->bcast_ip,d->bcast_ip);
	    }
	}
    }
}


/*******************************************************************
  what to do if a master browser DOESN't exist
  ******************************************************************/
void browser_gone(char *work_name, struct in_addr ip)
{
  struct subnet_record *d = find_subnet(ip);
  struct work_record *work = find_workgroupstruct(d, work_name, False);

  /* i don't know about this workgroup, therefore i don't care */
  if (!work || !d) return;

  /* don't do election stuff on the WINS subnet */
  if (ip_equal(d->bcast_ip,ipgrp)) 
    return;

  if (strequal(work->work_group, lp_workgroup()))
  {

      DEBUG(2,("Forcing election on %s %s\n",
	       work->work_group,inet_ntoa(d->bcast_ip)));

      /* we can attempt to become master browser */
      work->needelection = True;
  }
  else
  {
     /* local interfaces: force an election */
    send_election(d, work->work_group, 0, 0, myname);

     /* only removes workgroup completely on a local interface 
        persistent lmhosts entries on a local interface _will_ be removed).
      */
     remove_workgroup(d, work,True);
  }
}


/****************************************************************************
  send an election packet
  **************************************************************************/
void send_election(struct subnet_record *d, char *group,uint32 criterion,
		   int timeup,char *name)
{
  pstring outbuf;
  char *p;

  if (!d) return;
  
  DEBUG(2,("Sending election to %s for workgroup %s\n",
	   inet_ntoa(d->bcast_ip),group));	   

  bzero(outbuf,sizeof(outbuf));
  p = outbuf;
  CVAL(p,0) = ANN_Election; /* election */
  p++;

  CVAL(p,0) = (criterion == 0 && timeup == 0) ? 0 : ELECTION_VERSION;
  SIVAL(p,1,criterion);
  SIVAL(p,5,timeup*1000); /* ms - despite the spec */
  p += 13;
  strcpy(p,name);
  strupper(p);
  p = skip_string(p,1);
  
  send_mailslot_reply(BROWSE_MAILSLOT,ClientDGRAM,outbuf,PTR_DIFF(p,outbuf),
		      name,group,0,0x1e,d->bcast_ip,*iface_ip(d->bcast_ip));
}


/****************************************************************************
  un-register a SELF name that got rejected.

  if this name happens to be rejected when samba is in the process
  of becoming a master browser (registering __MSBROWSE__, WORKGROUP(1d)
  or WORKGROUP(1b)) then we must stop being a master browser. sad.

  **************************************************************************/
void name_unregister_work(struct subnet_record *d, char *name, int name_type)
{
    struct work_record *work;

    remove_netbios_name(d,name,name_type,SELF,ipzero);

    if (!(work = find_workgroupstruct(d, name, False))) return;

    if (ms_browser_name(name, name_type) ||
        (AM_MASTER(work) && strequal(name, lp_workgroup()) == 0 &&
         (name_type == 0x1d || name_type == 0x1b)))
    {
      int remove_type = 0;

      if (ms_browser_name(name, name_type))
        remove_type = SV_TYPE_MASTER_BROWSER|SV_TYPE_DOMAIN_MASTER;
      if (name_type == 0x1d)
        remove_type = SV_TYPE_MASTER_BROWSER;
      if (name_type == 0x1b)
        remove_type = SV_TYPE_DOMAIN_MASTER;
			
      become_nonmaster(d, work, remove_type);
    }
}


/****************************************************************************
  registers a name.

  if the name being added is a SELF name, we must additionally check
  whether to proceed to the next stage in samba becoming a master browser.

  **************************************************************************/
void name_register_work(struct subnet_record *d, char *name, int name_type,
				int nb_flags, time_t ttl, struct in_addr ip, BOOL bcast)
{
  enum name_source source = (ismyip(ip) || ip_equal(ip, ipzero)) ?
								SELF : REGISTER;

  if (source == SELF)
  {
    struct work_record *work = find_workgroupstruct(d, lp_workgroup(), False);

    add_netbios_entry(d,name,name_type,nb_flags,ttl,source,ip,True,!bcast);

    if (work)
    {
      if (work->state != MST_NONE)
      {
        /* samba is in the process of working towards master browser-ness.
           initiate the next stage.
         */
        become_master(d, work);
        return;
      }
    }
  }
}


/*******************************************************************
  become the master browser.

  this is done in stages. note that this could take a while, 
  particularly on a broadcast subnet, as we have to wait for
  the implicit registration of each name to be accepted.

  as each name is successfully registered, become_master() is
  called again, in order to initiate the next stage. see
  dead_netbios_entry() - deals with implicit name registration
  and response_name_reg() - deals with explicit registration
  with a WINS server.

  stage 1: was MST_NONE - go to MST_NONE and register ^1^2__MSBROWSE__^2^1.
  stage 2: was MST_WON  - go to MST_MSB  and register WORKGROUP(0x1d)
  stage 3: was MST_MSB  - go to MST_BROWSER and register WORKGROUP(0x1b)
  stage 4: was MST_BROWSER - go to MST_DOMAIN (do not pass GO, do not...)

  XXXX note: this code still does not cope with the distinction
  between different types of nodes, particularly between M and P
  nodes. that comes later.

  ******************************************************************/
void become_master(struct subnet_record *d, struct work_record *work)
{
  /* domain type must be limited to domain enum + server type. it must
     not have SV_TYPE_SERVER or anything else with SERVER in it, else
     clients get confused and start thinking this entry is a server
     not a workgroup
   */
  uint32 domain_type = SV_TYPE_DOMAIN_ENUM|SV_TYPE_NT;

  if (!work) return;
  
  DEBUG(2,("Becoming master for %s %s (currently at stage %d)\n",
					work->work_group,inet_ntoa(d->bcast_ip),work->state));
  
  switch (work->state)
  {
    case MST_NONE: /* while we were nothing but a server... */
    {
      DEBUG(3,("go to first stage: register ^1^2__MSBROWSE__^2^1\n"));
      work->state = MST_WON; /* ... an election win was successful */

      work->ElectionCriterion |= 0x5;

      /* update our server status */
      work->ServerType &= ~SV_TYPE_POTENTIAL_BROWSER;
      add_server_entry(d,work,myname,work->ServerType,0,lp_serverstring(),True);

      /* add special browser name */
      add_my_name_entry(d,MSBROWSE        ,0x01,nb_type|NB_ACTIVE|NB_GROUP);

      /* DON'T do anything else after calling add_my_name_entry() */
      return;
    }
    case MST_WON: /* while nothing had happened except we won an election... */
    {
      DEBUG(3,("go to second stage: register as master browser\n"));
      work->state = MST_MSB; /* ... registering MSBROWSE was successful */

      /* add server entry on successful registration of MSBROWSE */
      add_server_entry(d,work,work->work_group,domain_type,0,myname,True);

      /* add master name */
      add_my_name_entry(d,work->work_group,0x1d,nb_type|NB_ACTIVE);
  
      /* DON'T do anything else after calling add_my_name_entry() */
      return;
    }
    case MST_MSB: /* while we were still only registered MSBROWSE state... */
    {
      DEBUG(3,("2nd stage complete: registered as master browser\n"));
      work->state = MST_BROWSER; /* ... registering WORKGROUP(1d) succeeded */

      /* update our server status */
      work->ServerType |= SV_TYPE_MASTER_BROWSER;
      add_server_entry(d,work,myname,work->ServerType,0,lp_serverstring(),True);

      if (work->serverlist == NULL) /* no servers! */
      {
        /* ask all servers on our local net to announce to us */
        announce_request(work, d->bcast_ip);
      }
      break;
   }

   case MST_BROWSER:
   {
      /* don't have to do anything: just report success */
      DEBUG(3,("3rd stage: become master browser!\n"));

      break;
   }

   case MST_DOMAIN_NONE:
   {
      if (lp_domain_master())
      {
        work->state = MST_DOMAIN_MEM; /* ... become domain member */
        DEBUG(3,("domain first stage: register as domain member\n"));

        /* add domain member name */
        add_my_name_entry(d,work->work_group,0x1e,nb_type|NB_ACTIVE|NB_GROUP);

        /* DON'T do anything else after calling add_my_name_entry() */
        return;
      }
      else
      {
        DEBUG(4,("samba not configured as a domain master.\n"));
      }
  
      break;
   }

   case MST_DOMAIN_MEM:
   {
      if (lp_domain_master())
      {
        work->state = MST_DOMAIN_TST; /* ... possibly become domain master */
        DEBUG(3,("domain second stage: register as domain master\n"));

        if (lp_domain_logons())
	    {
          work->ServerType |= SV_TYPE_DOMAIN_MEMBER;
          add_server_entry(d,work,myname,work->ServerType,0,lp_serverstring(),True);
        }

        /* add domain master name */
        add_my_name_entry(d,work->work_group,0x1b,nb_type|NB_ACTIVE         );

        /* DON'T do anything else after calling add_my_name_entry() */
        return;
      }
      else
      {
        DEBUG(4,("samba not configured as a domain master.\n"));
      }
  
      break;
    }

    case MST_DOMAIN_TST: /* while we were still a master browser... */
    {
      /* update our server status */
      if (lp_domain_master())
      {
        struct subnet_record *d1;
		uint32 update_type = 0;

        DEBUG(3,("domain third stage: samba is now a domain master.\n"));
        work->state = MST_DOMAIN; /* ... registering WORKGROUP(1b) succeeded */

        update_type |= DFLT_SERVER_TYPE | SV_TYPE_DOMAIN_MASTER | 
	  SV_TYPE_POTENTIAL_BROWSER;

		work->ServerType |= update_type;
		add_server_entry(d,work,myname,work->ServerType,0,lp_serverstring(),True);

		for (d1 = subnetlist; d1; d1 = d1->next)
		{
        	struct work_record *w;
			if (ip_equal(d1->bcast_ip, d->bcast_ip)) continue;

        	for (w = d1->workgrouplist; w; w = w->next)
			{
				struct server_record *s = find_server(w, myname);
				if (strequal(w->work_group, work->work_group))
				{
					w->ServerType |= update_type;
				}
				if (s)
				{
					s->serv.type |= update_type;
					DEBUG(4,("found server %s on %s: update to %8x\n",
									s->serv.name, inet_ntoa(d1->bcast_ip),
									s->serv.type));
				}
			}
		}
      }
  
      break;
    }

    case MST_DOMAIN:
    {
      /* don't have to do anything: just report success */
      DEBUG(3,("fifth stage: there isn't one yet!\n"));
      break;
    }
  }
}


/*******************************************************************
  unbecome the master browser. initates removal of necessary netbios 
  names, and tells the world that we are no longer a master browser.
  ******************************************************************/
void become_nonmaster(struct subnet_record *d, struct work_record *work,
				int remove_type)
{
  int new_server_type = work->ServerType;

  DEBUG(2,("Becoming non-master for %s\n",work->work_group));
  
  /* can only remove master or domain types with this function */
  remove_type &= SV_TYPE_MASTER_BROWSER|SV_TYPE_DOMAIN_MASTER;

  /* unbecome a master browser; unbecome a domain master, too :-( */
  if (remove_type & SV_TYPE_MASTER_BROWSER)
    remove_type |= SV_TYPE_DOMAIN_MASTER;

  new_server_type &= ~remove_type;

  if (!(new_server_type & (SV_TYPE_MASTER_BROWSER|SV_TYPE_DOMAIN_MASTER)))
  {
    /* no longer a master browser of any sort */

    work->ServerType |= SV_TYPE_POTENTIAL_BROWSER;
    work->ElectionCriterion &= ~0x4;
    work->state = MST_NONE;

	/* announce ourselves as no longer active as a master browser. */
    announce_server(d, work, work->work_group, myname, 0, 0);
    remove_name_entry(d,MSBROWSE        ,0x01);
  }
  
  work->ServerType = new_server_type;

  if (!(work->ServerType & SV_TYPE_DOMAIN_MASTER))
  {
    if (work->state == MST_DOMAIN)
      work->state = MST_BROWSER;
    remove_name_entry(d,work->work_group,0x1b);    
  }

  if (!(work->ServerType & SV_TYPE_MASTER_BROWSER))
  {
    if (work->state >= MST_BROWSER)
      work->state = MST_NONE;
    remove_name_entry(d,work->work_group,0x1d);
  }
}


/*******************************************************************
  run the election
  ******************************************************************/
void run_elections(time_t t)
{
  static time_t lastime = 0;
  
  struct subnet_record *d;
  
  /* send election packets once a second */
  if (lastime && t-lastime <= 0) return;
  
  lastime = t;
  
  for (d = subnetlist; d; d = d->next)
  {
    struct work_record *work;
    for (work = d->workgrouplist; work; work = work->next)
	{
	  if (work->RunningElection)
	  {
	    send_election(d,work->work_group, work->ElectionCriterion,
			    t-StartupTime,myname);
	      
	    if (work->ElectionCount++ >= 4)
		{
		  /* I won! now what :-) */
		  DEBUG(2,(">>> Won election on %s %s <<<\n",
			   work->work_group,inet_ntoa(d->bcast_ip)));
		  
		  work->RunningElection = False;
		  work->state = MST_NONE;

		  become_master(d, work);
		}
	  }
	}
  }
}


/*******************************************************************
  work out if I win an election
  ******************************************************************/
static BOOL win_election(struct work_record *work,int version,uint32 criterion,
			 int timeup,char *name)
{  
  int mytimeup = time(NULL) - StartupTime;
  uint32 mycriterion = work->ElectionCriterion;

  DEBUG(4,("election comparison: %x:%x %x:%x %d:%d %s:%s\n",
	   version,ELECTION_VERSION,
	   criterion,mycriterion,
	   timeup,mytimeup,
	   name,myname));

  if (version > ELECTION_VERSION) return(False);
  if (version < ELECTION_VERSION) return(True);
  
  if (criterion > mycriterion) return(False);
  if (criterion < mycriterion) return(True);

  if (timeup > mytimeup) return(False);
  if (timeup < mytimeup) return(True);

  if (strcasecmp(myname,name) > 0) return(False);
  
  return(True);
}


/*******************************************************************
  process a election packet

  An election dynamically decides who will be the master. 
  ******************************************************************/
void process_election(struct packet_struct *p,char *buf)
{
  struct dgram_packet *dgram = &p->packet.dgram;
  struct in_addr ip = dgram->header.source_ip;
  struct subnet_record *d = find_subnet(ip);
  int version = CVAL(buf,0);
  uint32 criterion = IVAL(buf,1);
  int timeup = IVAL(buf,5)/1000;
  char *name = buf+13;
  struct work_record *work;

  if (!d) return;

  if (ip_equal(d->bcast_ip,ipgrp)) {
    DEBUG(3,("Unexpected election request from %s %s on WINS net\n",
	     name, inet_ntoa(p->ip)));
    return;
  }
  
  name[15] = 0;  

  DEBUG(3,("Election request from %s %s vers=%d criterion=%08x timeup=%d\n",
	   name,inet_ntoa(p->ip),version,criterion,timeup));
  
  if (same_context(dgram)) return;
  
  for (work = d->workgrouplist; work; work = work->next)
    {
      if (!strequal(work->work_group, lp_workgroup()))
	continue;

      if (win_election(work, version,criterion,timeup,name)) {
	if (!work->RunningElection) {
	  work->needelection = True;
	  work->ElectionCount=0;
	  work->state = MST_NONE;
	}
      } else {
	work->needelection = False;
	  
	if (work->RunningElection || AM_MASTER(work)) {
	  work->RunningElection = False;
	  DEBUG(3,(">>> Lost election on %s %s <<<\n",
		   work->work_group,inet_ntoa(d->bcast_ip)));
	  if (AM_MASTER(work))
	    become_nonmaster(d, work,
			     SV_TYPE_MASTER_BROWSER|
			     SV_TYPE_DOMAIN_MASTER);
	}
      }
    }
}


/****************************************************************************
  checks whether a browser election is to be run on any workgroup

  this function really ought to return the time between election
  packets (which depends on whether samba intends to be a domain
  master or a master browser) in milliseconds.

  ***************************************************************************/
BOOL check_elections(void)
{
  struct subnet_record *d;
  BOOL run_any_election = False;

  for (d = subnetlist; d; d = d->next)
    {
      struct work_record *work;
      for (work = d->workgrouplist; work; work = work->next)
	{
	  run_any_election |= work->RunningElection;
	  
	  if (work->needelection && !work->RunningElection)
	    {
	      DEBUG(3,(">>> Starting election on %s %s <<<\n",
		       work->work_group,inet_ntoa(d->bcast_ip)));
	      work->ElectionCount = 0;
	      work->RunningElection = True;
	      work->needelection = False;
	    }
	}
    }
  return run_any_election;
}