source/nameserv.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: nameserv.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    module nameserv contains name server management functions
  30 */
  31
  32 #include "includes.h"
  33
  34 extern int ClientNMB;
  35
  36 extern int DEBUGLEVEL;
  37
  38 extern pstring scope;
  39 extern pstring myname;
  40 extern fstring myworkgroup;
  41 extern char **my_netbios_names;
  42 extern struct in_addr ipzero;
  43 extern struct in_addr wins_ip;
  44
  45 extern struct subnet_record *subnetlist;
  46
  47 extern uint16 nb_type; /* samba's NetBIOS type */
  48
  49 /****************************************************************************
  50   remove an entry from the name list
  51
  52   note: the name will _always_ be removed
  53   XXXX at present, the name is removed _even_ if a WINS server says keep it.
  54
  55   ****************************************************************************/
  56 void remove_name_entry(struct subnet_record *d, char *name,int type)
  57 {
  58   /* XXXX BUG: if samba is offering WINS support, it should still broadcast
  59       a de-registration packet to the local subnet before removing the
  60       name from its local-subnet name database. */
  61
  62   struct name_record n;
  63   struct name_record *n2=NULL;
  64
  65   make_nmb_name(&n.name,name,type,scope);
  66
  67   if ((n2 = find_name_on_subnet(d, &n.name, FIND_SELF_NAME)))
  68   {
  69     /* check name isn't already being de-registered */
  70     if (NAME_DEREG(n2->ip_flgs[0].nb_flags))
  71       return;
  72
  73     /* mark the name as in the process of deletion. */
  74     n2->ip_flgs[0].nb_flags &= NB_DEREG;
  75   }
  76
  77   if (!n2) return;
  78
  79   /* Only remove names with non-zero death times. */
  80   if(n2->death_time == 0)
  81   {
  82     DEBUG(5,("remove_name_entry: Name %s(%d) has zero ttl - not removing.\n",
  83              name, type));
  84     return;
  85   }
  86
  87   /* remove the name immediately. even if the spec says we should
  88      first try to release them, this is too dangerous with our current
  89      name structures as otherwise we will end up replying to names we
  90      don't really own */
  91   remove_netbios_name(d,name,type,SELF);
  92
  93   if (ip_equal(d->bcast_ip, wins_ip))
  94   {
  95     if (!lp_wins_support())
  96     {
  97       /* not a WINS server: we have to release them on the network */
  98       queue_netbios_pkt_wins(ClientNMB,NMB_REL,NAME_RELEASE,
  99                              name, type, 0, 0,0,NULL,NULL,
 100                              ipzero, ipzero);
 101     }
 102   }
 103   else
 104   {
 105       /* local interface: release them on the network */
 106       queue_netbios_packet(d,ClientNMB,NMB_REL,NAME_RELEASE,
 107                          name, type, 0, 0,0,NULL,NULL,
 108                          True, False, d->bcast_ip, d->bcast_ip, 0);
 109   }
 110 }
 111
 112
 113 /****************************************************************************
 114   add an entry to the name list
 115
 116   big note: our name will _always_ be added (if there are no objections).
 117   it's just a matter of when this will be done (e.g after a time-out).
 118
 119   ****************************************************************************/
 120 void add_my_name_entry(struct subnet_record *d,char *name,int type,int nb_flags)
 121 {
 122   BOOL re_reg = False;
 123   struct nmb_name n;
 124
 125   if (!d) return;
 126
 127   /* not that it particularly matters, but if the SELF name already exists,
 128      it must be re-registered, rather than just registered */
 129
 130   make_nmb_name(&n, name, type, scope);
 131   if (find_name_on_subnet(d, &n, FIND_SELF_NAME))
 132         re_reg = True;
 133
 134   /* XXXX BUG: if samba is offering WINS support, it should still add the
 135      name entry to a local-subnet name database. see rfc1001.txt 15.1.1 p28
 136      regarding the point about M-nodes. */
 137
 138   if (ip_equal(d->bcast_ip, wins_ip))
 139   {
 140     if (lp_wins_support())
 141     {
 142       /* we are a WINS server. */
 143       if(lp_wins_support())
 144       {
 145         DEBUG(4,("add_my_name_entry: samba as WINS server adding: "));
 146       }
 147
 148       /* this will call add_netbios_entry() */
 149       name_register_work(d, name, type, nb_flags,0, ipzero, False);
 150     }
 151     else
 152     {
 153       DEBUG(4,("add_my_name_entry registering name %s with WINS server.\n",
 154                 name));
 155
 156       /* a time-to-live allows us to refresh this name with the WINS server. */
 157           queue_netbios_pkt_wins(ClientNMB,
 158                                  re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
 159                              name, type, nb_flags, GET_TTL(0),0,NULL,NULL,
 160                              ipzero, ipzero);
 161     }
 162   }
 163   else
 164   {
 165     /* broadcast the packet */
 166     queue_netbios_packet(d,ClientNMB,
 167          re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
 168          name, type, nb_flags, GET_TTL(0),0,NULL,NULL,
 169          True, False, d->bcast_ip, ipzero, 0);
 170   }
 171 }
 172
 173
 174 /****************************************************************************
 175   add the internet group <1c> domain logon names by wins unicast and broadcast.
 176   ****************************************************************************/
 177 void add_domain_logon_names(void)
 178 {
 179   struct subnet_record *d;
 180
 181   if (!lp_domain_logons()) return;
 182
 183   for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_INCLUDING_WINS(d))
 184   {
 185     struct work_record *work = find_workgroupstruct(d, myworkgroup, True);
 186
 187     if (work && work->log_state == LOGON_NONE)
 188     {
 189       struct nmb_name n;
 190       make_nmb_name(&n,myworkgroup,0x1c,scope);
 191
 192       if (!find_name_on_subnet(d, &n, FIND_SELF_NAME))
 193       {
 194         /* logon servers are group names. don't expect failure */
 195
 196         DEBUG(0,("%s attempting to become logon server for %s %s\n",
 197               timestring(), myworkgroup, inet_ntoa(d->bcast_ip)));
 198
 199         become_logon_server(d, work);
 200       }
 201     }
 202   }
 203 }
 204
 205
 206 /****************************************************************************
 207   add the <1b> domain master names by broadcast.
 208   ****************************************************************************/
 209 void add_domain_master_bcast(void)
 210 {
 211   struct subnet_record *d;
 212
 213   if (!lp_domain_master()) return;
 214
 215   for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_EXCLUDING_WINS(d))
 216   {
 217     struct work_record *work = find_workgroupstruct(d, myworkgroup, True);
 218
 219     if (work && work->dom_state == DOMAIN_NONE)
 220     {
 221       struct nmb_name n;
 222       make_nmb_name(&n,myworkgroup,0x1b,scope);
 223
 224       if (!find_name_on_subnet(d, &n, FIND_SELF_NAME))
 225       {
 226         DEBUG(0,("%s add_domain_names: attempting to become domain \
 227 master browser on workgroup %s %s\n", timestring(), myworkgroup, inet_ntoa(d->bcast_ip)));
 228
 229         /* send out a query to establish whether there's a
 230            domain controller on the local subnet.  if not,
 231            we can become a domain controller.  it's only
 232            polite that we check, before claiming the
 233            NetBIOS name 0x1b.
 234          */
 235
 236         DEBUG(0,("add_domain_names:querying subnet %s \
 237 for domain master on workgroup %s\n", inet_ntoa(d->bcast_ip), myworkgroup));
 238
 239         queue_netbios_packet(d,ClientNMB,NMB_QUERY,
 240                              NAME_QUERY_DOMAIN,
 241                              myworkgroup, 0x1b,
 242                              0, 0,0,NULL,NULL,
 243                              True, False,
 244                              d->bcast_ip, d->bcast_ip, 0);
 245       }
 246     }
 247   }
 248 }
 249
 250
 251 /****************************************************************************
 252   add the <1b> domain master name by wins unicast.
 253   ****************************************************************************/
 254 void add_domain_master_wins(void)
 255 {
 256   struct work_record *work;
 257
 258   if (!lp_domain_master() || wins_client_subnet == NULL) return;
 259
 260   work = find_workgroupstruct(wins_client_subnet, myworkgroup, True);
 261
 262   if (work && work->dom_state == DOMAIN_NONE)
 263   {
 264     struct nmb_name n;
 265     make_nmb_name(&n,myworkgroup,0x1b,scope);
 266
 267     if (!find_name_on_subnet(wins_client_subnet, &n, FIND_SELF_NAME))
 268     {
 269       DEBUG(0,("%s add_domain_names: attempting to become domain \
 270 master browser on workgroup %s %s\n",
 271       timestring(), myworkgroup, inet_ntoa(wins_client_subnet->bcast_ip)));
 272
 273       if (lp_wins_support())
 274       {
 275         /* use the wins server's capabilities (indirectly).  if
 276            someone has already registered the domain<1b>
 277            name with the WINS server, then the WINS
 278            server's job is to _check_ that the owner still
 279            wants it, before giving it away.
 280          */
 281
 282         DEBUG(1,("%s initiate become domain master for %s\n",
 283                     timestring(), myworkgroup));
 284
 285         become_domain_master(wins_client_subnet, work);
 286       }
 287       else
 288       {
 289         /* send out a query to establish whether there's a
 290            domain controller on the WINS subnet.  if not,
 291            we can become a domain controller.  it's only
 292            polite that we check, before claiming the
 293            NetBIOS name 0x1b.
 294          */
 295
 296         DEBUG(0,("add_domain_names:querying WINS \
 297 for domain master on workgroup %s\n", myworkgroup));
 298
 299         queue_netbios_pkt_wins(ClientNMB,NMB_QUERY,
 300                                NAME_QUERY_DOMAIN,
 301                                myworkgroup, 0x1b,
 302                                0, 0,0,NULL,NULL,
 303                                ipzero, ipzero);
 304       }
 305     }
 306   }
 307 }
 308
 309
 310 /****************************************************************************
 311   add the domain logon server and domain master browser names
 312
 313   this code was written so that several samba servers can co-operate in
 314   sharing the task of (one server) being a domain master, and of being
 315   domain logon servers.
 316
 317   **************************************************************************/
 318 void add_domain_names(time_t t)
 319 {
 320         static time_t lastrun = 0;
 321
 322         if (lastrun != 0 && t < lastrun + CHECK_TIME_ADD_DOM_NAMES * 60) return;
 323         lastrun = t;
 324
 325         /* do the "internet group" - <1c> names */
 326         add_domain_logon_names();
 327
 328         /* do the domain master names */
 329         if (wins_client_subnet != NULL)
 330         {
 331                 /* if the registration of the <1b> name is successful, then
 332                    add_domain_master_bcast() will be called.  this will
 333                    result in domain logon services being gracefully provided,
 334                    as opposed to the aggressive nature of 1.9.16p2 to 1.9.16p11.
 335
 336                    which, due to a bug in namelogon.c from 1.9.16p2 to 1.9.16p11
 337                    cannot _provide_ domain master / domain logon services!!!
 338
 339                  */
 340                 add_domain_master_wins();
 341         }
 342         else
 343         {
 344                 add_domain_master_bcast();
 345         }
 346 }
 347
 348 /****************************************************************************
 349   add the magic samba names, useful for finding samba servers
 350   **************************************************************************/
 351 void add_my_names(void)
 352 {
 353   struct subnet_record *d;
 354   /* each subnet entry, including WINS pseudo-subnet, has SELF names */
 355
 356   /* XXXX if there was a transport layer added to samba (ipx/spx etc) then
 357      there would be yet _another_ for-loop, this time on the transport type
 358    */
 359
 360   for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_INCLUDING_WINS(d))
 361   {
 362     int n;
 363
 364     /* Add all our names including aliases. */
 365     for (n=0; my_netbios_names[n]; n++)
 366     {
 367       add_my_name_entry(d, my_netbios_names[n],0x20,nb_type|NB_ACTIVE);
 368       add_my_name_entry(d, my_netbios_names[n],0x03,nb_type|NB_ACTIVE);
 369       add_my_name_entry(d, my_netbios_names[n],0x00,nb_type|NB_ACTIVE);
 370     }
 371
 372     /* these names are added permanently (ttl of zero) and will NOT be
 373        refreshed with the WINS server  */
 374     add_netbios_entry(d,"*",0x0,nb_type|NB_ACTIVE,0,SELF,d->myip,False);
 375     add_netbios_entry(d,"*",0x20,nb_type|NB_ACTIVE,0,SELF,d->myip,False);
 376     add_netbios_entry(d,"__SAMBA__",0x20,nb_type|NB_ACTIVE,0,SELF,d->myip,False);
 377     add_netbios_entry(d,"__SAMBA__",0x00,nb_type|NB_ACTIVE,0,SELF,d->myip,False);
 378   }
 379 }
 380
 381
 382 /****************************************************************************
 383   remove all the samba names... from a WINS server if necessary.
 384   **************************************************************************/
 385 void remove_my_names()
 386 {
 387         struct subnet_record *d;
 388
 389         for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_INCLUDING_WINS(d))
 390         {
 391                 struct name_record *n, *next;
 392
 393                 for (n = d->namelist; n; n = next)
 394                 {
 395                         next = n->next;
 396                         if (n->source == SELF)
 397                         {
 398                                 /* get all SELF names removed from the WINS server's database */
 399                                 /* XXXX note: problem occurs if this removes the wrong one! */
 400
 401                                 remove_name_entry(d,n->name.name, n->name.name_type);
 402                         }
 403                 }
 404         }
 405 }
 406
 407
 408 /*******************************************************************
 409   refresh my own names
 410   ******************************************************************/
 411 void refresh_my_names(time_t t)
 412 {
 413   struct subnet_record *d;
 414
 415   for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_INCLUDING_WINS(d))
 416   {
 417     struct name_record *n;
 418
 419     for (n = d->namelist; n; n = n->next)
 420     {
 421       /* each SELF name has an individual time to be refreshed */
 422       if (n->source == SELF && n->refresh_time < t &&
 423           n->death_time != 0)
 424       {
 425         add_my_name_entry(d,n->name.name,n->name.name_type,
 426                           n->ip_flgs[0].nb_flags);
 427         /* they get a new lease on life :-) */
 428         n->death_time += GET_TTL(0);
 429         n->refresh_time += GET_TTL(0);
 430       }
 431     }
 432   }
 433 }
 434
 435
 436 /*******************************************************************
 437   queries names occasionally. an over-cautious, non-trusting WINS server!
 438
 439   this function has been added because nmbd could be restarted. it
 440   is generally a good idea to check all the names that have been
 441   reloaded from file.
 442
 443   XXXX which names to poll and which not can be refined at a later date.
 444   ******************************************************************/
 445 void query_refresh_names(time_t t)
 446 {
 447         struct name_record *n;
 448         struct subnet_record *d = wins_client_subnet;
 449
 450         static time_t lasttime = 0;
 451
 452         int count = 0;
 453         int name_refresh_time = NAME_POLL_REFRESH_TIME;
 454         int max_count = name_refresh_time * 2 / NAME_POLL_INTERVAL;
 455         if (max_count > 10) max_count = 10;
 456
 457         name_refresh_time = NAME_POLL_INTERVAL * max_count / 2;
 458
 459         /* if (!lp_poll_wins()) return; polling of registered names allowed */
 460
 461         if (!d) return;
 462
 463     if (!lasttime) lasttime = t;
 464         if (t - lasttime < NAME_POLL_INTERVAL) return;
 465
 466     lasttime = time(NULL);
 467
 468         for (n = d->namelist; n; n = n->next)
 469         {
 470                 /* only do unique, registered names */
 471
 472                 if (n->source != REGISTER) continue;
 473                 if (!NAME_GROUP(n->ip_flgs[0].nb_flags)) continue;
 474
 475                 if (n->refresh_time < t)
 476                 {
 477                   DEBUG(3,("Polling name %s\n", namestr(&n->name)));
 478
 479           queue_netbios_packet(d,ClientNMB,NMB_QUERY,NAME_QUERY_CONFIRM,
 480                                 n->name.name, n->name.name_type,
 481                                 0,0,0,NULL,NULL,
 482                                 False,False,n->ip_flgs[0].ip,n->ip_flgs[0].ip,
 483                                 0);
 484                   count++;
 485                 }
 486
 487                 if (count >= max_count)
 488                 {
 489                         /* don't do too many of these at once, but do enough to
 490                            cover everyone in the list */
 491                         return;
 492                 }
 493
 494                 /* this name will be checked on again, if it's not removed */
 495                 n->refresh_time += name_refresh_time;
 496         }
 497 }
 498