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 1994-1996
   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 struct in_addr ipzero;
  41 extern struct in_addr ipgrp;
  42
  43 extern struct subnet_record *subnetlist;
  44
  45 extern uint16 nb_type; /* samba's NetBIOS type */
  46
  47 /****************************************************************************
  48   remove an entry from the name list
  49
  50   note: the name will _always_ be removed
  51   XXXX at present, the name is removed _even_ if a WINS server says keep it.
  52
  53   ****************************************************************************/
  54 void remove_name_entry(struct subnet_record *d, char *name,int type)
  55 {
  56   /* XXXX BUG: if samba is offering WINS support, it should still broadcast
  57       a de-registration packet to the local subnet before removing the
  58       name from its local-subnet name database. */
  59
  60   struct name_record n;
  61   struct name_record *n2=NULL;
  62
  63   make_nmb_name(&n.name,name,type,scope);
  64
  65   if ((n2 = find_name_search(&d, &n.name, FIND_SELF, ipzero)))
  66   {
  67     /* check name isn't already being de-registered */
  68     if (NAME_DEREG(n2->ip_flgs[0].nb_flags))
  69       return;
  70
  71     /* mark the name as in the process of deletion. */
  72     n2->ip_flgs[0].nb_flags &= NB_DEREG;
  73   }
  74
  75   if (!n2) return;
  76
  77   /* remove the name immediately. even if the spec says we should
  78      first try to release them, this is too dangerous with our current
  79      name structures as otherwise we will end up replying to names we
  80      don't really own */
  81   remove_netbios_name(d,name,type,SELF,n2->ip_flgs[0].ip);
  82
  83   if (ip_equal(d->bcast_ip, ipgrp))
  84   {
  85     if (!lp_wins_support())
  86     {
  87       /* not a WINS server: we have to release them on the network */
  88       queue_netbios_pkt_wins(d,ClientNMB,NMB_REL,NAME_RELEASE,
  89                              name, type, 0, 0,0,NULL,NULL,
  90                              False, True, ipzero, ipzero);
  91     }
  92   }
  93   else
  94   {
  95     /* local interface: release them on the network */
  96     queue_netbios_packet(d,ClientNMB,NMB_REL,NAME_RELEASE,
  97                          name, type, 0, 0,0,NULL,NULL,
  98                          True, True, d->bcast_ip, d->bcast_ip);
  99   }
 100 }
 101
 102
 103 /****************************************************************************
 104   add an entry to the name list
 105
 106   big note: our name will _always_ be added (if there are no objections).
 107   it's just a matter of when this will be done (e.g after a time-out).
 108
 109   ****************************************************************************/
 110 void add_my_name_entry(struct subnet_record *d,char *name,int type,int nb_flags)
 111 {
 112   BOOL re_reg = False;
 113   struct nmb_name n;
 114
 115   if (!d) return;
 116
 117   /* not that it particularly matters, but if the SELF name already exists,
 118      it must be re-registered, rather than just registered */
 119
 120   make_nmb_name(&n, name, type, scope);
 121   if (find_name(d->namelist, &n, SELF))
 122         re_reg = True;
 123
 124   /* XXXX BUG: if samba is offering WINS support, it should still add the
 125      name entry to a local-subnet name database. see rfc1001.txt 15.1.1 p28
 126      regarding the point about M-nodes. */
 127
 128   if (ip_equal(d->bcast_ip, ipgrp))
 129   {
 130     if (lp_wins_support())
 131     {
 132       /* we are a WINS server. */
 133       /* XXXX assume that if we are a WINS server that we are therefore
 134          not pointing to another WINS server as well. this may later NOT
 135          actually be true
 136        */
 137
 138       DEBUG(4,("samba as WINS server adding: "));
 139       /* this will call add_netbios_entry() */
 140       name_register_work(d, name, type, nb_flags,0, ipzero, False);
 141     }
 142     else
 143     {
 144       /* a time-to-live allows us to refresh this name with the WINS server. */
 145           queue_netbios_pkt_wins(d,ClientNMB,
 146                                  re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
 147                              name, type, nb_flags, GET_TTL(0),0,NULL,NULL,
 148                              False, True, ipzero, ipzero);
 149     }
 150   }
 151   else
 152   {
 153     /* broadcast the packet, but it comes from ipzero */
 154         queue_netbios_packet(d,ClientNMB,
 155                                  re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
 156                              name, type, nb_flags, GET_TTL(0),0,NULL,NULL,
 157                              True, True, d->bcast_ip, ipzero);
 158   }
 159 }
 160
 161
 162 /****************************************************************************
 163   add the domain logon server and domain master browser names
 164
 165   this code was written so that several samba servers can co-operate in
 166   sharing the task of (one server) being a domain master, and of being
 167   domain logon servers.
 168
 169   **************************************************************************/
 170 void add_domain_names(time_t t)
 171 {
 172   static time_t lastrun = 0;
 173   struct subnet_record *d;
 174
 175   if (lastrun != 0 && t < lastrun + CHECK_TIME_ADD_DOM_NAMES * 60) return;
 176   lastrun = t;
 177
 178   for (d = subnetlist; d; d = d->next)
 179   {
 180     struct work_record *work = find_workgroupstruct(d, lp_workgroup(), False);
 181     struct nmb_name n;
 182
 183     if (lp_domain_logons() && work && work->log_state == LOGON_NONE)
 184     {
 185       make_nmb_name(&n,lp_workgroup(),0x1c,scope);
 186       if (!find_name(d->namelist, &n, FIND_SELF))
 187       {
 188         /* logon servers are group names - we don't expect this to fail. */
 189         DEBUG(0,("%s attempting to become logon server for %s %s\n",
 190              timestring(), lp_workgroup(), inet_ntoa(d->bcast_ip)));
 191         become_logon_server(d, work);
 192       }
 193     }
 194
 195     if (lp_domain_master() && work && work->dom_state == DOMAIN_NONE)
 196     {
 197       make_nmb_name(&n,lp_workgroup(),0x1b,scope);
 198       if (!find_name(d->namelist, &n, FIND_SELF))
 199       {
 200         if (ip_equal(d->bcast_ip,ipgrp))
 201         {
 202           if (lp_wins_support())
 203           {
 204             /* use the wins server's capabilities (indirectly).  if
 205                someone has already register the domain<1b> name with
 206                the WINS server, then the WINS server's job is to _check_
 207                that the owner still wants it, before giving it away.
 208              */
 209
 210             DEBUG(1,("%s initiating becoming logon server for %s %s\n",
 211                         timestring(), lp_workgroup(), inet_ntoa(d->bcast_ip)));
 212             become_domain_master(d, work);
 213           }
 214         }
 215         else
 216         {
 217           /* send out a query to establish whether there's a
 218              domain controller on the local subnet.  if not,
 219              we can become a domain controller on that subnet.
 220              it's only polite that we check, before claiming the
 221              NetBIOS name 0x1b.
 222            */
 223
 224           queue_netbios_packet(d,ClientNMB,NMB_QUERY,NAME_QUERY_DOMAIN,
 225                                 lp_workgroup(), 0x1b,
 226                                 0, 0,0,NULL,NULL,
 227                                 True, True, d->bcast_ip, d->bcast_ip);
 228         }
 229       }
 230     }
 231   }
 232 }
 233
 234
 235 /****************************************************************************
 236   add the magic samba names, useful for finding samba servers
 237   **************************************************************************/
 238 void add_my_names(void)
 239 {
 240   struct subnet_record *d;
 241   /* each subnet entry, including WINS pseudo-subnet, has SELF names */
 242
 243   /* XXXX if there was a transport layer added to samba (ipx/spx etc) then
 244      there would be yet _another_ for-loop, this time on the transport type
 245    */
 246
 247   for (d = subnetlist; d; d = d->next)
 248   {
 249     BOOL wins = lp_wins_support() && ip_equal(d->bcast_ip,ipgrp);
 250     struct work_record *work = find_workgroupstruct(d, lp_workgroup(), False);
 251
 252     add_my_name_entry(d, myname,0x20,nb_type|NB_ACTIVE);
 253     add_my_name_entry(d, myname,0x03,nb_type|NB_ACTIVE);
 254     add_my_name_entry(d, myname,0x00,nb_type|NB_ACTIVE);
 255     add_my_name_entry(d, myname,0x1f,nb_type|NB_ACTIVE);
 256
 257     /* these names are added permanently (ttl of zero) and will NOT be
 258        refreshed with the WINS server  */
 259     add_netbios_entry(d,"*",0x0,nb_type|NB_ACTIVE,0,SELF,d->myip,False,wins);
 260     add_netbios_entry(d,"*",0x20,nb_type|NB_ACTIVE,0,SELF,d->myip,False,wins);
 261     add_netbios_entry(d,"__SAMBA__",0x20,nb_type|NB_ACTIVE,0,SELF,d->myip,False,wins);
 262     add_netbios_entry(d,"__SAMBA__",0x00,nb_type|NB_ACTIVE,0,SELF,d->myip,False,wins);
 263
 264     if (lp_domain_logons() && work && work->log_state == LOGON_NONE)
 265     {
 266       become_logon_server(d, work);
 267     }
 268     if (lp_domain_master() && work && work->dom_state == DOMAIN_NONE)
 269     {
 270       become_domain_master(d, work);
 271     }
 272   }
 273 }
 274
 275
 276 /****************************************************************************
 277   remove all the samba names... from a WINS server if necessary.
 278   **************************************************************************/
 279 void remove_my_names()
 280 {
 281         struct subnet_record *d;
 282
 283         for (d = subnetlist; d; d = d->next)
 284         {
 285                 struct name_record *n, *next;
 286
 287                 for (n = d->namelist; n; n = next)
 288                 {
 289                         next = n->next;
 290                         if (n->source == SELF)
 291                         {
 292                                 /* get all SELF names removed from the WINS server's database */
 293                                 /* XXXX note: problem occurs if this removes the wrong one! */
 294
 295                                 remove_name_entry(d,n->name.name, n->name.name_type);
 296                         }
 297                 }
 298         }
 299 }
 300
 301
 302 /*******************************************************************
 303   refresh my own names
 304   ******************************************************************/
 305 void refresh_my_names(time_t t)
 306 {
 307   struct subnet_record *d;
 308
 309   for (d = subnetlist; d; d = d->next)
 310   {
 311     struct name_record *n;
 312
 313         for (n = d->namelist; n; n = n->next)
 314     {
 315       /* each SELF name has an individual time to be refreshed */
 316       if (n->source == SELF && n->refresh_time < t &&
 317           n->death_time != 0)
 318       {
 319         add_my_name_entry(d,n->name.name,n->name.name_type,
 320                           n->ip_flgs[0].nb_flags);
 321         /* they get a new lease on life :-) */
 322         n->death_time += GET_TTL(0);
 323         n->refresh_time += GET_TTL(0);
 324       }
 325     }
 326   }
 327 }
 328
 329
 330 /*******************************************************************
 331   queries names occasionally. an over-cautious, non-trusting WINS server!
 332
 333   this function has been added because nmbd could be restarted. it
 334   is generally a good idea to check all the names that have been
 335   reloaded from file.
 336
 337   XXXX which names to poll and which not can be refined at a later date.
 338   ******************************************************************/
 339 void query_refresh_names(time_t t)
 340 {
 341         struct name_record *n;
 342         struct subnet_record *d = find_subnet(ipgrp);
 343
 344         static time_t lasttime = 0;
 345
 346         int count = 0;
 347         int name_refresh_time = NAME_POLL_REFRESH_TIME;
 348         int max_count = name_refresh_time * 2 / NAME_POLL_INTERVAL;
 349         if (max_count > 10) max_count = 10;
 350
 351         name_refresh_time = NAME_POLL_INTERVAL * max_count / 2;
 352
 353         /* if (!lp_poll_wins()) return; polling of registered names allowed */
 354
 355         if (!d) return;
 356
 357     if (!lasttime) lasttime = t;
 358         if (t - lasttime < NAME_POLL_INTERVAL) return;
 359
 360     lasttime = time(NULL);
 361
 362         for (n = d->namelist; n; n = n->next)
 363         {
 364                 /* only do unique, registered names */
 365
 366                 if (n->source != REGISTER) continue;
 367                 if (!NAME_GROUP(n->ip_flgs[0].nb_flags)) continue;
 368
 369                 if (n->refresh_time < t)
 370                 {
 371                   DEBUG(3,("Polling name %s\n", namestr(&n->name)));
 372
 373           queue_netbios_packet(d,ClientNMB,NMB_QUERY,NAME_QUERY_CONFIRM,
 374                                 n->name.name, n->name.name_type,
 375                                 0,0,0,NULL,NULL,
 376                                 False,False,n->ip_flgs[0].ip,n->ip_flgs[0].ip);
 377                   count++;
 378                 }
 379
 380                 if (count >= max_count)
 381                 {
 382                         /* don't do too many of these at once, but do enough to
 383                            cover everyone in the list */
 384                         return;
 385                 }
 386
 387                 /* this name will be checked on again, if it's not removed */
 388                 n->refresh_time += name_refresh_time;
 389         }
 390 }
 391