source/namedbname.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: namedbname.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    created module namedbname containing name database functions
  30 */
  31
  32 #include "includes.h"
  33
  34 extern int DEBUGLEVEL;
  35
  36 extern pstring scope;
  37 extern struct in_addr ipzero;
  38 extern struct in_addr ipgrp;
  39
  40 extern struct subnet_record *subnetlist;
  41
  42 #define WINS_LIST "wins.dat"
  43
  44
  45 /****************************************************************************
  46   true if two netbios names are equal
  47 ****************************************************************************/
  48 BOOL name_equal(struct nmb_name *n1,struct nmb_name *n2)
  49 {
  50   return n1->name_type == n2->name_type &&
  51                  strequal(n1->name ,n2->name ) &&
  52          strequal(n1->scope,n2->scope);
  53 }
  54
  55
  56 /****************************************************************************
  57   true if the netbios name is ^1^2__MSBROWSE__^2^1
  58
  59   note: this name is registered if as a master browser or backup browser
  60   you are responsible for a workgroup (when you announce a domain by
  61   broadcasting on your local subnet, you announce it as coming from this
  62   name: see announce_host()).
  63
  64   **************************************************************************/
  65 BOOL ms_browser_name(char *name, int type)
  66 {
  67   return strequal(name,MSBROWSE) && type == 0x01;
  68 }
  69
  70
  71 /****************************************************************************
  72   add a netbios name into the namelist
  73   **************************************************************************/
  74 static void add_name(struct subnet_record *d, struct name_record *n)
  75 {
  76   struct name_record *n2;
  77
  78   if (!d) return;
  79
  80   if (!d->namelist)
  81   {
  82     d->namelist = n;
  83     n->prev = NULL;
  84     n->next = NULL;
  85     return;
  86   }
  87
  88   for (n2 = d->namelist; n2->next; n2 = n2->next) ;
  89
  90   n2->next = n;
  91   n->next = NULL;
  92   n->prev = n2;
  93 }
  94
  95
  96 /****************************************************************************
  97   remove a name from the namelist. The pointer must be an element just
  98   retrieved
  99   **************************************************************************/
 100 void remove_name(struct subnet_record *d, struct name_record *n)
 101 {
 102   struct name_record *nlist;
 103   if (!d) return;
 104
 105   nlist = d->namelist;
 106
 107   while (nlist && nlist != n) nlist = nlist->next;
 108
 109   if (nlist)
 110   {
 111     if (nlist->next) nlist->next->prev = nlist->prev;
 112     if (nlist->prev) nlist->prev->next = nlist->next;
 113     free(nlist);
 114   }
 115 }
 116
 117
 118 /****************************************************************************
 119   find a name in a namelist.
 120   **************************************************************************/
 121 struct name_record *find_name(struct name_record *n,
 122                         struct nmb_name *name,
 123                         int search, struct in_addr ip)
 124 {
 125         struct name_record *ret;
 126
 127         for (ret = n; ret; ret = ret->next)
 128         {
 129                 if (name_equal(&ret->name,name))
 130                 {
 131                         /* self search: self names only */
 132                         if ((search&FIND_SELF) == FIND_SELF && ret->source != SELF)
 133                                 continue;
 134
 135                         /* zero ip is either samba's ip or a way of finding a
 136                            name without needing to know the ip address */
 137                         if (zero_ip(ip) || ip_equal(ip, ret->ip))
 138                         {
 139                                 return ret;
 140                         }
 141                 }
 142         }
 143     return NULL;
 144 }
 145
 146
 147 /****************************************************************************
 148   find a name in the domain database namelist
 149   search can be any of:
 150   FIND_SELF - look exclusively for names the samba server has added for itself
 151   FIND_LOCAL - look for names in the local subnet record.
 152   FIND_WINS - look for names in the WINS record
 153   **************************************************************************/
 154 struct name_record *find_name_search(struct subnet_record **d,
 155                         struct nmb_name *name,
 156                         int search, struct in_addr ip)
 157 {
 158         if (d == NULL) return NULL; /* bad error! */
 159
 160     if ((search & FIND_LOCAL) == FIND_LOCAL)
 161         {
 162                 if (*d != NULL)
 163         {
 164                         return find_name((*d)->namelist, name, search, ip);
 165                 }
 166         else
 167         {
 168                         DEBUG(4,("local find_name_search with a NULL subnet pointer\n"));
 169             return NULL;
 170                 }
 171         }
 172
 173         if ((search & FIND_WINS) != FIND_WINS) return NULL;
 174
 175         if (*d == NULL)
 176         {
 177                 /* find WINS subnet record */
 178                 *d = find_subnet(ipgrp);
 179     }
 180
 181         if (*d == NULL) return NULL;
 182
 183         return find_name((*d)->namelist, name, search, ip);
 184 }
 185
 186
 187 /****************************************************************************
 188   dump a copy of the name table
 189   **************************************************************************/
 190 void dump_names(void)
 191 {
 192   struct name_record *n;
 193   struct subnet_record *d;
 194   fstring fname, fnamenew;
 195   time_t t = time(NULL);
 196
 197   FILE *f;
 198
 199   strcpy(fname,lp_lockdir());
 200   trim_string(fname,NULL,"/");
 201   strcat(fname,"/");
 202   strcat(fname,WINS_LIST);
 203   strcpy(fnamenew,fname);
 204   strcat(fnamenew,".");
 205
 206   f = fopen(fnamenew,"w");
 207
 208   if (!f)
 209   {
 210     DEBUG(4,("Can't open %s - %s\n",fnamenew,strerror(errno)));
 211   }
 212
 213   DEBUG(3,("Dump of local name table:\n"));
 214
 215   for (d = subnetlist; d; d = d->next)
 216    for (n = d->namelist; n; n = n->next)
 217     {
 218       if (f && ip_equal(d->bcast_ip, ipgrp) && n->source == REGISTER)
 219       {
 220         fstring data;
 221
 222       /* XXXX i have little imagination as to how to output nb_flags as
 223          anything other than as a hexadecimal number :-) */
 224
 225         sprintf(data, "%s#%02x %s %2x %ld",
 226                n->name.name,n->name.name_type, /* XXXX ignore the scope for now */
 227                inet_ntoa(n->ip),
 228                n->nb_flags,
 229                n->death_time);
 230             fprintf(f, "%s\n", data);
 231       }
 232
 233           DEBUG(3,("%15s ", inet_ntoa(d->bcast_ip)));
 234           DEBUG(3,("%15s ", inet_ntoa(d->mask_ip)));
 235       DEBUG(3,("%-19s %15s NB=%2x TTL=%ld \n",
 236                namestr(&n->name),
 237                inet_ntoa(n->ip),
 238                n->nb_flags,
 239            n->death_time?n->death_time-t:0));
 240     }
 241
 242   fclose(f);
 243   unlink(fname);
 244   chmod(fnamenew,0644);
 245   rename(fnamenew,fname);
 246
 247   DEBUG(3,("Wrote wins database %s\n",fname));
 248 }
 249
 250
 251 /****************************************************************************
 252 load a netbios name database file
 253 ****************************************************************************/
 254 void load_netbios_names(void)
 255 {
 256   struct subnet_record *d = find_subnet(ipgrp);
 257   fstring fname;
 258
 259   FILE *f;
 260   pstring line;
 261
 262   if (!d) return;
 263
 264   strcpy(fname,lp_lockdir());
 265   trim_string(fname,NULL,"/");
 266   strcat(fname,"/");
 267   strcat(fname,WINS_LIST);
 268
 269   f = fopen(fname,"r");
 270
 271   if (!f) {
 272     DEBUG(2,("Can't open wins database file %s\n",fname));
 273     return;
 274   }
 275
 276   while (!feof(f))
 277     {
 278       pstring name_str, ip_str, ttd_str, nb_flags_str;
 279
 280       pstring name;
 281       int type = 0;
 282       int nb_flags;
 283       time_t ttd;
 284           struct in_addr ipaddr;
 285
 286           enum name_source source;
 287
 288       char *ptr;
 289           int count = 0;
 290
 291       char *p;
 292
 293       if (!fgets_slash(line,sizeof(pstring),f)) continue;
 294
 295       if (*line == '#') continue;
 296
 297         ptr = line;
 298
 299         if (next_token(&ptr,name_str    ,NULL)) ++count;
 300         if (next_token(&ptr,ip_str      ,NULL)) ++count;
 301         if (next_token(&ptr,ttd_str     ,NULL)) ++count;
 302         if (next_token(&ptr,nb_flags_str,NULL)) ++count;
 303
 304         if (count <= 0) continue;
 305
 306         if (count != 4) {
 307           DEBUG(0,("Ill formed wins line"));
 308           DEBUG(0,("[%s]: name#type ip nb_flags abs_time\n",line));
 309           continue;
 310         }
 311
 312       /* netbios name. # divides the name from the type (hex): netbios#xx */
 313       strcpy(name,name_str);
 314
 315       p = strchr(name,'#');
 316
 317       if (p) {
 318             *p = 0;
 319             sscanf(p+1,"%x",&type);
 320       }
 321
 322       /* decode the netbios flags (hex) and the time-to-die (seconds) */
 323           sscanf(nb_flags_str,"%x",&nb_flags);
 324           sscanf(ttd_str,"%ld",&ttd);
 325
 326           ipaddr = *interpret_addr2(ip_str);
 327
 328       if (ip_equal(ipaddr,ipzero)) {
 329          source = SELF;
 330       }
 331       else
 332       {
 333          source = REGISTER;
 334       }
 335
 336       DEBUG(4, ("add WINS line: %s#%02x %s %ld %2x\n",
 337                name,type, inet_ntoa(ipaddr), ttd, nb_flags));
 338
 339       /* add all entries that have 60 seconds or more to live */
 340       if (ttd - 60 < time(NULL) || ttd == 0)
 341       {
 342         time_t t = (ttd?ttd-time(NULL):0) / 3;
 343
 344         /* add netbios entry read from the wins.dat file. IF it's ok */
 345         add_netbios_entry(d,name,type,nb_flags,t,source,ipaddr,True,True);
 346       }
 347     }
 348
 349   fclose(f);
 350 }
 351
 352
 353 /****************************************************************************
 354   remove an entry from the name list
 355   ****************************************************************************/
 356 void remove_netbios_name(struct subnet_record *d,
 357                         char *name,int type, enum name_source source,
 358                          struct in_addr ip)
 359 {
 360   struct nmb_name nn;
 361   struct name_record *n;
 362
 363   make_nmb_name(&nn, name, type, scope);
 364   n = find_name_search(&d, &nn, FIND_LOCAL, ip);
 365
 366   if (n && n->source == source) remove_name(d,n);
 367 }
 368
 369
 370 /****************************************************************************
 371   add an entry to the name list.
 372
 373   this is a multi-purpose function.
 374
 375   it adds samba's own names in to its records on each interface, keeping a
 376   record of whether it is a master browser, domain master, or WINS server.
 377
 378   it also keeps a record of WINS entries.
 379
 380   ****************************************************************************/
 381 struct name_record *add_netbios_entry(struct subnet_record *d,
 382                 char *name, int type, int nb_flags,
 383                 int ttl, enum name_source source, struct in_addr ip,
 384                 BOOL new_only,BOOL wins)
 385 {
 386   struct name_record *n;
 387   struct name_record *n2=NULL;
 388   int search = 0;
 389   BOOL self = source == SELF;
 390
 391   /* add the name to the WINS list if the name comes from a directed query */
 392   search |= wins ? FIND_WINS : FIND_LOCAL;
 393   /* search for SELF names only */
 394   search |= self ? FIND_SELF : 0;
 395
 396   if (!self)
 397   {
 398     if (!wins && type != 0x1b)
 399     {
 400        /* the only broadcast (non-WINS) names we are adding are ours
 401           (SELF) and PDC type names */
 402        return NULL;
 403     }
 404   }
 405
 406   n = (struct name_record *)malloc(sizeof(*n));
 407   if (!n) return(NULL);
 408
 409   bzero((char *)n,sizeof(*n));
 410
 411   make_nmb_name(&n->name,name,type,scope);
 412
 413   if ((n2 = find_name_search(&d, &n->name, search, new_only?ipzero:ip)))
 414   {
 415     free(n);
 416     if (new_only || (n2->source==SELF && source!=SELF)) return n2;
 417     n = n2;
 418   }
 419
 420   if (ttl)
 421      n->death_time = time(NULL)+ttl*3;
 422   n->refresh_time = time(NULL)+GET_TTL(ttl);
 423
 424   n->ip = ip;
 425   n->nb_flags = nb_flags;
 426   n->source = source;
 427
 428   if (!n2) add_name(d,n);
 429
 430   DEBUG(3,("Added netbios name %s at %s ttl=%d nb_flags=%2x\n",
 431                 namestr(&n->name),inet_ntoa(ip),ttl,nb_flags));
 432
 433   return(n);
 434 }
 435
 436
 437 /*******************************************************************
 438   expires old names in the namelist
 439   ******************************************************************/
 440 void expire_names(time_t t)
 441 {
 442         struct name_record *n;
 443         struct name_record *next;
 444         struct subnet_record *d;
 445
 446         /* expire old names */
 447         for (d = subnetlist; d; d = d->next)
 448         {
 449           for (n = d->namelist; n; n = next)
 450                 {
 451                   if (n->death_time && n->death_time < t)
 452                 {
 453                   DEBUG(3,("Removing dead name %s\n", namestr(&n->name)));
 454
 455                   next = n->next;
 456
 457                   if (n->prev) n->prev->next = n->next;
 458                   if (n->next) n->next->prev = n->prev;
 459
 460                   if (d->namelist == n) d->namelist = n->next;
 461
 462                   free(n);
 463                 }
 464                   else
 465                 {
 466                   next = n->next;
 467                 }
 468                 }
 469         }
 470 }
 471
 472
 473 /***************************************************************************
 474   reply to a name query
 475   ****************************************************************************/
 476 struct name_record *search_for_name(struct subnet_record **d,
 477                                         struct nmb_name *question,
 478                                     struct in_addr ip, int Time, int search)
 479 {
 480   int name_type = question->name_type;
 481   char *qname = question->name;
 482   BOOL dns_type = name_type == 0x20 || name_type == 0;
 483
 484   struct name_record *n;
 485
 486   DEBUG(3,("Search for %s from %s - ", namestr(question), inet_ntoa(ip)));
 487
 488   /* first look up name in cache */
 489   n = find_name_search(d,question,search,ip);
 490
 491   if (*d == NULL) return NULL;
 492
 493   DEBUG(4,("subnet %s ", inet_ntoa((*d)->bcast_ip)));
 494
 495   /* now try DNS lookup. */
 496   if (!n)
 497     {
 498       struct in_addr dns_ip;
 499       unsigned long a;
 500
 501       /* only do DNS lookups if the query is for type 0x20 or type 0x0 */
 502       if (!dns_type && name_type != 0x1b)
 503         {
 504           DEBUG(3,("types 0x20 0x1b 0x0 only: name not found\n"));
 505           return NULL;
 506         }
 507
 508       /* look it up with DNS */
 509       a = interpret_addr(qname);
 510
 511       putip((char *)&dns_ip,(char *)&a);
 512
 513       if (!a)
 514         {
 515           /* no luck with DNS. We could possibly recurse here XXXX */
 516           DEBUG(3,("no recursion.\n"));
 517       /* add the fail to our WINS cache of names. give it 1 hour in the cache */
 518           add_netbios_entry(*d,qname,name_type,NB_ACTIVE,60*60,DNSFAIL,dns_ip,
 519                                                 True, True);
 520           return NULL;
 521         }
 522
 523       /* add it to our WINS cache of names. give it 2 hours in the cache */
 524       n = add_netbios_entry(*d,qname,name_type,NB_ACTIVE,2*60*60,DNS,dns_ip,
 525                                                 True,True);
 526
 527       /* failed to add it? yikes! */
 528       if (!n) return NULL;
 529     }
 530
 531   /* is our entry already dead? */
 532   if (n->death_time)
 533     {
 534       if (n->death_time < Time) return False;
 535     }
 536
 537   /* it may have been an earlier failure */
 538   if (n->source == DNSFAIL)
 539     {
 540       DEBUG(3,("DNSFAIL\n"));
 541       return NULL;
 542     }
 543
 544   DEBUG(3,("OK %s\n",inet_ntoa(n->ip)));
 545
 546   return n;
 547 }
 548
 549