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
  46 /****************************************************************************
  47   remove an entry from the name list
  48
  49   note: the name will _always_ be removed: it's just a matter of when.
  50   XXXX at present, the name is removed _even_ if a WINS server says keep it.
  51
  52   ****************************************************************************/
  53 void remove_name_entry(struct subnet_record *d, char *name,int type)
  54 {
  55   /* XXXX BUG: if samba is offering WINS support, it should still broadcast
  56       a de-registration packet to the local subnet before removing the
  57       name from its local-subnet name database. */
  58
  59   struct name_record n;
  60   struct name_record *n2=NULL;
  61
  62   make_nmb_name(&n.name,name,type,scope);
  63
  64   if ((n2 = find_name_search(&d, &n.name, FIND_SELF, ipzero)))
  65   {
  66     /* check name isn't already being de-registered */
  67     if (NAME_DEREG(n2->nb_flags))
  68       return;
  69
  70     /* mark the name as in the process of deletion. */
  71     n2->nb_flags &= NB_DEREG;
  72   }
  73
  74   if (ip_equal(d->bcast_ip, ipgrp))
  75   {
  76     if (lp_wins_support())
  77     {
  78         /* we are a WINS server. */
  79         /* XXXX assume that if we are a WINS server that we are therefore
  80            not pointing to another WINS server as well. this may later NOT
  81            actually be true
  82          */
  83         remove_netbios_name(d,name,type,SELF,ipzero);
  84     }
  85     else
  86     {
  87       /* not a WINS server: cannot just remove our own names: we have to
  88          release them on the network first. ask permission from the WINS
  89          server, or if no reply is received, then we can remove the name */
  90
  91         queue_netbios_pkt_wins(d,ClientNMB,NMB_REL,NAME_RELEASE,
  92                  name, type, 0, 0,
  93                  False, True, ipzero, ipzero);
  94     }
  95   }
  96   else
  97   {
  98      /* local interface: cannot just remove our own names: we have to
  99         release them on the network first. once no reply is received,
 100         then we can remove the name. */
 101
 102      queue_netbios_packet(d,ClientNMB,NMB_REL,NAME_RELEASE,
 103                              name, type, 0, 0,
 104                              True, True, d->bcast_ip, d->bcast_ip);
 105   }
 106 }
 107
 108
 109 /****************************************************************************
 110   add an entry to the name list
 111
 112   big note: our name will _always_ be added (if there are no objections).
 113   it's just a matter of when this will be done (e.g after a time-out).
 114
 115   ****************************************************************************/
 116 void add_my_name_entry(struct subnet_record *d,char *name,int type,int nb_flags)
 117 {
 118   BOOL re_reg = False;
 119   struct nmb_name n;
 120
 121   if (!d) return;
 122
 123   /* not that it particularly matters, but if the SELF name already exists,
 124      it must be re-registered, rather than just registered */
 125
 126   make_nmb_name(&n, name, type, scope);
 127   if (find_name(d->namelist, &n, SELF, ipzero))
 128         re_reg = True;
 129
 130   /* XXXX BUG: if samba is offering WINS support, it should still add the
 131      name entry to a local-subnet name database. see rfc1001.txt 15.1.1 p28
 132      regarding the point about M-nodes. */
 133
 134   if (ip_equal(d->bcast_ip, ipgrp))
 135   {
 136     if (lp_wins_support())
 137     {
 138       /* we are a WINS server. */
 139       /* XXXX assume that if we are a WINS server that we are therefore
 140          not pointing to another WINS server as well. this may later NOT
 141          actually be true
 142        */
 143
 144       add_netbios_entry(d,name,type,nb_flags,0,
 145                                 SELF,ipzero,False,lp_wins_support());
 146     }
 147     else
 148     {
 149       /* a time-to-live allows us to refresh this name with the WINS server. */
 150           queue_netbios_pkt_wins(d,ClientNMB,
 151                                  re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
 152                              name, type, nb_flags, GET_TTL(0),
 153                              False, True, ipzero, ipzero);
 154     }
 155   }
 156   else
 157   {
 158         queue_netbios_packet(d,ClientNMB,
 159                                  re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
 160                              name, type, nb_flags, GET_TTL(0),
 161                              True, True, d->bcast_ip, d->bcast_ip);
 162   }
 163 }
 164
 165
 166 /****************************************************************************
 167   add the magic samba names, useful for finding samba servers
 168   **************************************************************************/
 169 void add_my_names(void)
 170 {
 171   BOOL wins = lp_wins_support();
 172   struct subnet_record *d;
 173
 174   struct in_addr ip = ipzero;
 175
 176   /* each subnet entry, including WINS pseudo-subnet, has SELF names */
 177
 178   /* XXXX if there was a transport layer added to samba (ipx/spx etc) then
 179      there would be yet _another_ for-loop, this time on the transport type
 180    */
 181
 182   for (d = subnetlist; d; d = d->next)
 183   {
 184     if (!d->my_interface) continue;
 185
 186     /* these names need to be refreshed with the WINS server */
 187         add_my_name_entry(d, myname,0x20,NB_ACTIVE);
 188         add_my_name_entry(d, myname,0x03,NB_ACTIVE);
 189         add_my_name_entry(d, myname,0x00,NB_ACTIVE);
 190         add_my_name_entry(d, myname,0x1f,NB_ACTIVE);
 191
 192     /* these names are added permanently (ttl of zero) and will NOT be
 193        refreshed with the WINS server  */
 194         add_netbios_entry(d,"*",0x0,NB_ACTIVE,0,SELF,ip,False,wins);
 195         add_netbios_entry(d,"__SAMBA__",0x20,NB_ACTIVE,0,SELF,ip,False,wins);
 196         add_netbios_entry(d,"__SAMBA__",0x00,NB_ACTIVE,0,SELF,ip,False,wins);
 197
 198     if (lp_domain_logons() && lp_domain_master()) {
 199         /* XXXX the 0x1c is apparently something to do with domain logons */
 200           add_my_name_entry(d, my_workgroup(),0x1c,NB_ACTIVE|NB_GROUP);
 201     }
 202   }
 203 }
 204
 205
 206 /****************************************************************************
 207   remove all the samba names... from a WINS server if necessary.
 208   **************************************************************************/
 209 void remove_my_names()
 210 {
 211         struct subnet_record *d;
 212
 213         for (d = subnetlist; d; d = d->next)
 214         {
 215                 struct name_record *n, *next;
 216
 217                 for (n = d->namelist; n; n = next)
 218                 {
 219                         next = n->next;
 220                         if (n->source == SELF)
 221                         {
 222                                 /* get all SELF names removed from the WINS server's database */
 223                                 /* XXXX note: problem occurs if this removes the wrong one! */
 224
 225                                 remove_name_entry(d,n->name.name, n->name.name_type);
 226                         }
 227                 }
 228         }
 229 }
 230
 231
 232 /*******************************************************************
 233   refresh my own names
 234   ******************************************************************/
 235 void refresh_my_names(time_t t)
 236 {
 237   struct subnet_record *d;
 238
 239   for (d = subnetlist; d; d = d->next)
 240   {
 241     struct name_record *n;
 242
 243         for (n = d->namelist; n; n = n->next)
 244     {
 245       /* each SELF name has an individual time to be refreshed */
 246       if (n->source == SELF && n->refresh_time < time(NULL) &&
 247           n->death_time != 0)
 248       {
 249         add_my_name_entry(d,n->name.name,n->name.name_type,n->nb_flags);
 250       }
 251     }
 252   }
 253 }
 254
 255
 256 /*******************************************************************
 257   queries names occasionally. an over-cautious, non-trusting WINS server!
 258
 259   this function has been added because nmbd could be restarted. it
 260   is generally a good idea to check all the names that have been
 261   reloaded from file.
 262
 263   XXXX which names to poll and which not can be refined at a later date.
 264   ******************************************************************/
 265 void query_refresh_names(void)
 266 {
 267         struct name_record *n;
 268         struct subnet_record *d = find_subnet(ipgrp);
 269
 270         static time_t lasttime = 0;
 271         time_t t = time(NULL);
 272
 273         int count = 0;
 274         int name_refresh_time = NAME_POLL_REFRESH_TIME;
 275         int max_count = name_refresh_time * 2 / NAME_POLL_INTERVAL;
 276         if (max_count > 10) max_count = 10;
 277
 278         name_refresh_time = NAME_POLL_INTERVAL * max_count / 2;
 279
 280         /* if (!lp_poll_wins()) return; polling of registered names allowed */
 281
 282         if (!d) return;
 283
 284     if (!lasttime) lasttime = t;
 285         if (t - lasttime < NAME_POLL_INTERVAL) return;
 286
 287     lasttime = time(NULL);
 288
 289         for (n = d->namelist; n; n = n->next)
 290         {
 291                 /* only do unique, registered names */
 292
 293                 if (n->source != REGISTER) continue;
 294                 if (!NAME_GROUP(n->nb_flags)) continue;
 295
 296                 if (n->refresh_time < t)
 297                 {
 298                   DEBUG(3,("Polling name %s\n", namestr(&n->name)));
 299
 300           queue_netbios_packet(d,ClientNMB,NMB_QUERY,NAME_QUERY_CONFIRM,
 301                                 n->name.name, n->name.name_type,
 302                                 0,0,
 303                                 False,False,n->ip,n->ip);
 304                   count++;
 305                 }
 306
 307                 if (count >= max_count)
 308                 {
 309                         /* don't do too many of these at once, but do enough to
 310                            cover everyone in the list */
 311                         return;
 312                 }
 313
 314                 /* this name will be checked on again, if it's not removed */
 315                 n->refresh_time += name_refresh_time;
 316         }
 317 }
 318