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 pstring ServerComment;
  41 extern struct in_addr ipzero;
  42 extern struct in_addr ipgrp;
  43
  44 extern struct subnet_record *subnetlist;
  45
  46
  47 /****************************************************************************
  48   remove an entry from the name list
  49
  50   note: the name will _always_ be removed: it's just a matter of when.
  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->nb_flags))
  69       return;
  70
  71     /* mark the name as in the process of deletion. */
  72     n2->nb_flags &= NB_DEREG;
  73   }
  74
  75   if (ip_equal(d->bcast_ip, ipgrp))
  76   {
  77     if (lp_wins_support())
  78     {
  79         /* we are a WINS server. */
  80         /* XXXX assume that if we are a WINS server that we are therefore
  81            not pointing to another WINS server as well. this may later NOT
  82            actually be true
  83          */
  84         remove_netbios_name(d,name,type,SELF,ipzero);
  85     }
  86     else
  87     {
  88       /* not a WINS server: cannot just remove our own names: we have to
  89          release them on the network first. ask permission from the WINS
  90          server, or if no reply is received, then we can remove the name */
  91
  92         queue_netbios_pkt_wins(d,ClientNMB,NMB_REL,NAME_RELEASE,
  93                  name, type, 0, 0,
  94                  False, True, ipzero, ipzero);
  95     }
  96   }
  97   else
  98   {
  99      /* local interface: cannot just remove our own names: we have to
 100         release them on the network first. once no reply is received,
 101         then we can remove the name. */
 102
 103      queue_netbios_packet(d,ClientNMB,NMB_REL,NAME_RELEASE,
 104                              name, type, 0, 0,
 105                              True, True, d->bcast_ip, d->bcast_ip);
 106   }
 107 }
 108
 109
 110 /****************************************************************************
 111   add an entry to the name list
 112
 113   big note: our name will _always_ be added (if there are no objections).
 114   it's just a matter of when this will be done (e.g after a time-out).
 115
 116   ****************************************************************************/
 117 void add_my_name_entry(struct subnet_record *d,char *name,int type,int nb_flags)
 118 {
 119   BOOL re_reg = False;
 120   struct nmb_name n;
 121
 122   if (!d) return;
 123
 124   /* not that it particularly matters, but if the SELF name already exists,
 125      it must be re-registered, rather than just registered */
 126
 127   make_nmb_name(&n, name, type, scope);
 128   if (find_name(d->namelist, &n, SELF))
 129         re_reg = True;
 130
 131   /* XXXX BUG: if samba is offering WINS support, it should still add the
 132      name entry to a local-subnet name database. see rfc1001.txt 15.1.1 p28
 133      regarding the point about M-nodes. */
 134
 135   if (ip_equal(d->bcast_ip, ipgrp))
 136   {
 137     if (lp_wins_support())
 138     {
 139       /* we are a WINS server. */
 140       /* XXXX assume that if we are a WINS server that we are therefore
 141          not pointing to another WINS server as well. this may later NOT
 142          actually be true
 143        */
 144
 145       DEBUG(4,("samba as WINS server adding: "));
 146       /* this will call add_netbios_entry() */
 147       name_register_work(d, name, type, nb_flags,0, ipzero, False);
 148     }
 149     else
 150     {
 151       /* a time-to-live allows us to refresh this name with the WINS server. */
 152           queue_netbios_pkt_wins(d,ClientNMB,
 153                                  re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
 154                              name, type, nb_flags, GET_TTL(0),
 155                              False, True, ipzero, ipzero);
 156     }
 157   }
 158   else
 159   {
 160     /* broadcast the packet, but it comes from ipzero */
 161         queue_netbios_packet(d,ClientNMB,
 162                                  re_reg ? NMB_REG_REFRESH : NMB_REG, NAME_REGISTER,
 163                              name, type, nb_flags, GET_TTL(0),
 164                              True, True, d->bcast_ip, ipzero);
 165   }
 166 }
 167
 168
 169 /****************************************************************************
 170   add the magic samba names, useful for finding samba servers
 171   **************************************************************************/
 172 void add_my_names(void)
 173 {
 174   BOOL wins = lp_wins_support();
 175   struct subnet_record *d;
 176
 177   struct in_addr ip = ipzero;
 178
 179   /* each subnet entry, including WINS pseudo-subnet, has SELF names */
 180
 181   /* XXXX if there was a transport layer added to samba (ipx/spx etc) then
 182      there would be yet _another_ for-loop, this time on the transport type
 183    */
 184
 185   for (d = subnetlist; d; d = d->next)
 186   {
 187     BOOL wins_iface = ip_equal(d->bcast_ip, ipgrp);
 188
 189     if (!d->my_interface && !wins_iface) continue;
 190
 191         add_my_name_entry(d, myname,0x20,NB_ACTIVE);
 192         add_my_name_entry(d, myname,0x03,NB_ACTIVE);
 193         add_my_name_entry(d, myname,0x00,NB_ACTIVE);
 194         add_my_name_entry(d, myname,0x1f,NB_ACTIVE);
 195
 196     /* these names are added permanently (ttl of zero) and will NOT be
 197        refreshed with the WINS server  */
 198         add_netbios_entry(d,"*",0x0,NB_ACTIVE,0,SELF,ip,False,wins);
 199         add_netbios_entry(d,"__SAMBA__",0x20,NB_ACTIVE,0,SELF,ip,False,wins);
 200         add_netbios_entry(d,"__SAMBA__",0x00,NB_ACTIVE,0,SELF,ip,False,wins);
 201
 202     if (!wins_iface && lp_domain_logons() && lp_domain_master()) {
 203         /* XXXX the 0x1c is apparently something to do with domain logons */
 204           add_my_name_entry(d, my_workgroup(),0x1c,NB_ACTIVE|NB_GROUP);
 205     }
 206   }
 207   if (lp_domain_master() && (d = find_subnet(ipgrp)))
 208   {
 209     struct work_record *work = find_workgroupstruct(d, lp_workgroup(), True);
 210     if (work && work->state == MST_NONE)
 211     {
 212       work->state = MST_DOMAIN_NONE;
 213       become_master(d, work);
 214     }
 215   }
 216 }
 217
 218
 219 /****************************************************************************
 220   remove all the samba names... from a WINS server if necessary.
 221   **************************************************************************/
 222 void remove_my_names()
 223 {
 224         struct subnet_record *d;
 225
 226         for (d = subnetlist; d; d = d->next)
 227         {
 228                 struct name_record *n, *next;
 229
 230                 for (n = d->namelist; n; n = next)
 231                 {
 232                         next = n->next;
 233                         if (n->source == SELF)
 234                         {
 235                                 /* get all SELF names removed from the WINS server's database */
 236                                 /* XXXX note: problem occurs if this removes the wrong one! */
 237
 238                                 remove_name_entry(d,n->name.name, n->name.name_type);
 239                         }
 240                 }
 241         }
 242 }
 243
 244
 245 /*******************************************************************
 246   refresh my own names
 247   ******************************************************************/
 248 void refresh_my_names(time_t t)
 249 {
 250   struct subnet_record *d;
 251
 252   for (d = subnetlist; d; d = d->next)
 253   {
 254     struct name_record *n;
 255
 256         for (n = d->namelist; n; n = n->next)
 257     {
 258       /* each SELF name has an individual time to be refreshed */
 259       if (n->source == SELF && n->refresh_time < time(NULL) &&
 260           n->death_time != 0)
 261       {
 262         add_my_name_entry(d,n->name.name,n->name.name_type,n->nb_flags);
 263       }
 264     }
 265   }
 266 }
 267
 268
 269 /*******************************************************************
 270   queries names occasionally. an over-cautious, non-trusting WINS server!
 271
 272   this function has been added because nmbd could be restarted. it
 273   is generally a good idea to check all the names that have been
 274   reloaded from file.
 275
 276   XXXX which names to poll and which not can be refined at a later date.
 277   ******************************************************************/
 278 void query_refresh_names(void)
 279 {
 280         struct name_record *n;
 281         struct subnet_record *d = find_subnet(ipgrp);
 282
 283         static time_t lasttime = 0;
 284         time_t t = time(NULL);
 285
 286         int count = 0;
 287         int name_refresh_time = NAME_POLL_REFRESH_TIME;
 288         int max_count = name_refresh_time * 2 / NAME_POLL_INTERVAL;
 289         if (max_count > 10) max_count = 10;
 290
 291         name_refresh_time = NAME_POLL_INTERVAL * max_count / 2;
 292
 293         /* if (!lp_poll_wins()) return; polling of registered names allowed */
 294
 295         if (!d) return;
 296
 297     if (!lasttime) lasttime = t;
 298         if (t - lasttime < NAME_POLL_INTERVAL) return;
 299
 300     lasttime = time(NULL);
 301
 302         for (n = d->namelist; n; n = n->next)
 303         {
 304                 /* only do unique, registered names */
 305
 306                 if (n->source != REGISTER) continue;
 307                 if (!NAME_GROUP(n->nb_flags)) continue;
 308
 309                 if (n->refresh_time < t)
 310                 {
 311                   DEBUG(3,("Polling name %s\n", namestr(&n->name)));
 312
 313           queue_netbios_packet(d,ClientNMB,NMB_QUERY,NAME_QUERY_CONFIRM,
 314                                 n->name.name, n->name.name_type,
 315                                 0,0,
 316                                 False,False,n->ip,n->ip);
 317                   count++;
 318                 }
 319
 320                 if (count >= max_count)
 321                 {
 322                         /* don't do too many of these at once, but do enough to
 323                            cover everyone in the list */
 324                         return;
 325                 }
 326
 327                 /* this name will be checked on again, if it's not removed */
 328                 n->refresh_time += name_refresh_time;
 329         }
 330 }
 331