source/nameservreply.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: nameservreply.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 nameservreply containing NetBIOS reply functions
  30
  31 */
  32
  33 #include "includes.h"
  34
  35 extern int ClientNMB;
  36
  37 extern int DEBUGLEVEL;
  38
  39 extern struct in_addr wins_ip;
  40
  41
  42 /****************************************************************************
  43   add a netbios entry. respond to the (possibly new) owner.
  44   **************************************************************************/
  45 void add_name_respond(struct subnet_record *d, int fd, struct in_addr from_ip,
  46                                 uint16 response_id,
  47                                 struct nmb_name *name,
  48                                 int nb_flags, int ttl, struct in_addr register_ip,
  49                                 BOOL new_owner, struct in_addr reply_to_ip)
  50 {
  51         /* register the old or the new owners' ip */
  52         add_netbios_entry(d,name->name,name->name_type,
  53                                                 nb_flags,ttl,REGISTER,register_ip,False,True);
  54
  55         /* reply yes or no to the host that requested the name */
  56         send_name_response(fd,from_ip, response_id, NMB_REG,
  57                                 new_owner, True,
  58                                 name, nb_flags, ttl, reply_to_ip);
  59 }
  60
  61 /****************************************************************************
  62 send a registration / release response: pos/neg
  63 **************************************************************************/
  64 void send_name_response(int fd, struct in_addr from_ip,
  65                                 int name_trn_id, int opcode, BOOL success, BOOL recurse,
  66                                 struct nmb_name *reply_name, int nb_flags, int ttl,
  67                                 struct in_addr ip)
  68 {
  69   char rdata[6];
  70   struct packet_struct p;
  71
  72   int rcode = 0;
  73
  74   if (success == False)
  75   {
  76     /* NEGATIVE RESPONSE */
  77     rcode = 6;
  78   }
  79   else if (opcode == NMB_REG && recurse == False)
  80   {
  81     /* END-NODE CHALLENGE REGISTRATION RESPONSE */
  82         rcode = 0;
  83   }
  84
  85   rdata[0] = nb_flags;
  86   rdata[1] = 0;
  87   putip(&rdata[2],(char *)&ip);
  88
  89   p.ip = from_ip;
  90   p.port = NMB_PORT;
  91   p.fd = fd;
  92   p.timestamp = time(NULL);
  93   p.packet_type = NMB_PACKET;
  94
  95   reply_netbios_packet(&p,name_trn_id,
  96                        rcode,opcode,opcode,recurse,
  97                        reply_name, 0x20, 0x1,
  98                        ttl,
  99                        rdata, 6);
 100 }
 101
 102
 103 /****************************************************************************
 104 reply to a name release
 105 ****************************************************************************/
 106 void reply_name_release(struct packet_struct *p)
 107 {
 108   struct nmb_packet *nmb = &p->packet.nmb;
 109   struct in_addr ip;
 110   int nb_flags = nmb->additional->rdata[0];
 111   BOOL bcast = nmb->header.nm_flags.bcast;
 112   struct name_record *n;
 113   struct subnet_record *d = NULL;
 114   int search = 0;
 115   BOOL success = False;
 116
 117   putip((char *)&ip,&nmb->additional->rdata[2]);
 118
 119   DEBUG(3,("Name release on name %s\n",
 120            namestr(&nmb->question.question_name)));
 121
 122   if (!(d = find_req_subnet(p->ip, bcast)))
 123     {
 124       DEBUG(3,("response packet: bcast %s not known\n",
 125                inet_ntoa(p->ip)));
 126       return;
 127     }
 128
 129   if (bcast)
 130     search |= FIND_LOCAL;
 131   else
 132     search |= FIND_WINS;
 133
 134   n = find_name_search(&d, &nmb->question.question_name,
 135                        search, ip);
 136
 137   /* XXXX under what conditions should we reject the removal?? */
 138   if (n && n->ip_flgs[0].nb_flags == nb_flags)
 139     {
 140       success = True;
 141
 142       remove_name(d,n);
 143       n = NULL;
 144     }
 145
 146   if (bcast) return;
 147
 148   /* Send a NAME RELEASE RESPONSE (pos/neg) see rfc1002.txt 4.2.10-11 */
 149   send_name_response(p->fd,p->ip, nmb->header.name_trn_id, NMB_REL,
 150                      success, False,
 151                      &nmb->question.question_name, nb_flags, 0, ip);
 152 }
 153
 154
 155 /****************************************************************************
 156 reply to a reg request
 157 **************************************************************************/
 158 void reply_name_reg(struct packet_struct *p)
 159 {
 160   struct nmb_packet *nmb = &p->packet.nmb;
 161   struct nmb_name *question = &nmb->question.question_name;
 162
 163   struct nmb_name *reply_name = question;
 164
 165   char *qname      = question->name;
 166   int   qname_type = question->name_type;
 167
 168   BOOL bcast = nmb->header.nm_flags.bcast;
 169
 170   int ttl = GET_TTL(nmb->additional->ttl);
 171   int nb_flags = nmb->additional->rdata[0];
 172   BOOL group = NAME_GROUP(nb_flags);
 173
 174   struct subnet_record *d = NULL;
 175   struct name_record *n = NULL;
 176
 177   BOOL success = True;
 178   BOOL secured_redirect = False;
 179
 180   struct in_addr ip, from_ip;
 181   int search = 0;
 182
 183   putip((char *)&from_ip,&nmb->additional->rdata[2]);
 184   ip = from_ip;
 185
 186   DEBUG(3,("Name registration for name %s at %s - ",
 187                    namestr(question),inet_ntoa(ip)));
 188
 189   if (group)
 190     {
 191       /* apparently we should return 255.255.255.255 for group queries
 192          (email from MS) */
 193       ip = wins_ip;
 194     }
 195
 196   if (!(d = find_req_subnet(p->ip, bcast)))
 197   {
 198     DEBUG(3,("response packet: bcast %s not known\n",
 199                                 inet_ntoa(p->ip)));
 200     return;
 201   }
 202
 203   if (bcast)
 204         search |= FIND_LOCAL;
 205   else
 206         search |= FIND_WINS;
 207
 208   /* see if the name already exists */
 209   n = find_name_search(&d, question, search, from_ip);
 210
 211   if (n)
 212   {
 213     DEBUG(3,("found\n"));
 214     if (!group) /* unique names */
 215         {
 216           if (n->source == SELF || NAME_GROUP(n->ip_flgs[0].nb_flags))
 217           {
 218               /* no-one can register one of samba's names, nor can they
 219                  register a name that's a group name as a unique name */
 220
 221               success = False;
 222           }
 223           else if(!ip_equal(ip, n->ip_flgs[0].ip))
 224           {
 225               /* XXXX rfc1001.txt says:
 226                * if we are doing secured WINS, we must send a Wait-Acknowledge
 227                * packet (WACK) to the person who wants the name, then do a
 228                * name query on the person who currently owns the unique name.
 229                * if the current owner still says they own it, the person who wants
 230                    * the name can't have it. if they do not, or are not alive, they can.
 231                */
 232
 233           secured_redirect = True;
 234
 235               reply_name = &n->name;
 236           }
 237           else
 238           {
 239               n->ip_flgs[0].ip = ip;
 240               n->death_time = ttl?p->timestamp+ttl*3:0;
 241               DEBUG(3,("%s owner: %s\n",namestr(&n->name),inet_ntoa(n->ip_flgs[0].ip)));
 242           }
 243         }
 244     else
 245         {
 246           /* refresh the name */
 247           if (n->source != SELF)
 248           {
 249               n->death_time = ttl?p->timestamp + ttl*3:0;
 250           }
 251         }
 252
 253     /* XXXX bug reported by terryt@ren.pc.athabascau.ca */
 254     /* names that people have checked for and not found get DNSFAILed.
 255        we need to update the name record if someone then registers */
 256
 257     if (n->source == DNSFAIL)
 258       n->source = REGISTER;
 259
 260   }
 261   else
 262   {
 263       DEBUG(3,("not found\n"));
 264       /* add the name to our name/subnet, or WINS, database */
 265       n = add_netbios_entry(d,qname,qname_type,nb_flags,ttl,REGISTER,ip,
 266                                 True,!bcast);
 267   }
 268
 269   /* if samba owns a unique name on a subnet, then it must respond and
 270      disallow the attempted registration. if the registration is
 271      successful by broadcast, only then is there no need to respond
 272      (implicit registration: see rfc1001.txt 15.2.1).
 273    */
 274
 275   if (bcast && success) return;
 276
 277   if (secured_redirect)
 278   {
 279     char rdata[2];
 280
 281     /* XXXX i am confused. RSVAL or SSVAL? assume NMB byte ordering */
 282     RSSVAL(rdata,0,(nmb->header.opcode&0xf) + ((nb_flags&0xff) << 4));
 283
 284     /* XXXX mistake in rfc1002.txt? 4.2.16: NULL is 0xa see 4.2.1.3
 285        type  = 0x0a; see rfc1002.txt 4.2.1.3
 286        class = 0x01; see rfc1002.txt 4.2.16
 287      */
 288
 289     /* send WAIT ACKNOWLEDGEMENT see rfc1002.txt 4.2.16 */
 290     reply_netbios_packet(p,nmb->header.name_trn_id,
 291                        0,NMB_WAIT_ACK,NMB_WAIT_ACK,False,
 292                        reply_name, 0x0a, 0x01,
 293                        15*1000, /* 15 seconds long enough to wait? */
 294                        rdata, 2);
 295
 296     /* initiate some enquiries to the current owner. */
 297         queue_netbios_packet(d,ClientNMB,NMB_QUERY,
 298                                                  NAME_REGISTER_CHALLENGE,
 299                                                  reply_name->name,reply_name->name_type,
 300                              nb_flags,0,0,NULL,NULL,
 301                                                  False, False, n->ip_flgs[0].ip, p->ip);
 302   }
 303   else
 304   {
 305     /* Send a NAME REGISTRATION RESPONSE (pos/neg) see rfc1002.txt 4.2.13-14
 306        or an END-NODE CHALLENGE REGISTRATION RESPONSE see rfc1002.txt 4.2.7
 307      */
 308
 309         send_name_response(p->fd,p->ip, nmb->header.name_trn_id, NMB_REG,
 310                                                 success, True,
 311                                                 reply_name, nb_flags, ttl, ip);
 312   }
 313 }
 314
 315 /* this is used to sort names for a name status into a sensible order
 316    we put our own names first, then in alphabetical order */
 317 static int status_compare(char *n1,char *n2)
 318 {
 319   extern pstring myname;
 320   int l1,l2,l3;
 321
 322   /* its a bit tricky because the names are space padded */
 323   for (l1=0;l1<15 && n1[l1] && n1[l1] != ' ';l1++) ;
 324   for (l2=0;l2<15 && n2[l2] && n2[l2] != ' ';l2++) ;
 325   l3 = strlen(myname);
 326
 327   if ((l1==l3) && strncmp(n1,myname,l3) == 0 &&
 328       (l2!=l3 || strncmp(n2,myname,l3) != 0))
 329     return -1;
 330
 331   if ((l2==l3) && strncmp(n2,myname,l3) == 0 &&
 332       (l1!=l3 || strncmp(n1,myname,l3) != 0))
 333     return 1;
 334
 335   return memcmp(n1,n2,18);
 336 }
 337
 338
 339 /****************************************************************************
 340   reply to a name status query
 341
 342   combine the list of the local interface on which the query was made with
 343   the names registered via wins.
 344   ****************************************************************************/
 345 void reply_name_status(struct packet_struct *p)
 346 {
 347   struct nmb_packet *nmb = &p->packet.nmb;
 348   char *qname   = nmb->question.question_name.name;
 349   int ques_type = nmb->question.question_name.name_type;
 350   char rdata[MAX_DGRAM_SIZE];
 351   char *countptr, *buf, *bufend, *buf0;
 352   int names_added,i;
 353   struct name_record *n;
 354   struct subnet_record *d = NULL;
 355   int search = FIND_SELF | FIND_WINS | FIND_LOCAL;
 356
 357   /* NOTE: we always treat a name status lookup as a bcast */
 358   if (!(d = find_req_subnet(p->ip, True)))
 359   {
 360     DEBUG(3,("Name status req: bcast %s not known\n",
 361                         inet_ntoa(p->ip)));
 362     return;
 363   }
 364
 365   DEBUG(3,("Name status for name %s %s\n",
 366            namestr(&nmb->question.question_name),
 367            inet_ntoa(p->ip)));
 368
 369   n = find_name_search(&d, &nmb->question.question_name,
 370                                 search, p->ip);
 371
 372   if (!n) return;
 373
 374   /* XXXX hack, we should calculate exactly how many will fit */
 375   bufend = &rdata[MAX_DGRAM_SIZE] - 18;
 376   countptr = buf = rdata;
 377   buf += 1;
 378   buf0 = buf;
 379
 380   names_added = 0;
 381
 382   n = d->namelist;
 383
 384   while (buf < bufend)
 385   {
 386     if (n->source == SELF)
 387     {
 388       int name_type = n->name.name_type;
 389
 390       /* check if we want to exclude other workgroup names
 391              from the response. if we don't exclude them, windows clients
 392              get confused and will respond with an error for NET VIEW */
 393
 394       if (!strequal(n->name.name,"*") &&
 395           !strequal(n->name.name,"__SAMBA__") &&
 396           (name_type < 0x1b || name_type >= 0x20 ||
 397            ques_type < 0x1b || ques_type >= 0x20 ||
 398            strequal(qname, n->name.name)))
 399       {
 400         /* start with first bit of putting info in buffer: the name */
 401         bzero(buf,18);
 402             sprintf(buf,"%-15.15s",n->name.name);
 403         strupper(buf);
 404
 405         /* put name type and netbios flags in buffer */
 406         buf[15] = name_type;
 407         buf[16]  = n->ip_flgs[0].nb_flags;
 408
 409         buf += 18;
 410
 411         names_added++;
 412       }
 413     }
 414
 415     /* remove duplicate names */
 416     qsort(buf0,names_added,18,QSORT_CAST status_compare);
 417
 418     for (i=1;i<names_added;i++) {
 419       if (memcmp(buf0 + 18*i,buf0 + 18*(i-1),16) == 0) {
 420         names_added--;
 421         if (names_added == i) break;
 422         memmove(buf0 + 18*i,buf0 + 18*(i+1),18*(names_added-i));
 423         i--;
 424       }
 425     }
 426
 427     buf = buf0 + 18*names_added;
 428
 429     n = n->next;
 430
 431     if (!n)
 432     {
 433       /* end of this name list: add wins names too? */
 434       struct subnet_record *w_d;
 435
 436       if (!(w_d = wins_subnet)) break;
 437
 438       if (w_d != d)
 439       {
 440         d = w_d;
 441         n = d->namelist; /* start on the wins name list */
 442       }
 443         }
 444         if (!n) break;
 445   }
 446
 447   SCVAL(countptr,0,names_added);
 448
 449   /* XXXXXXX we should fill in more fields of the statistics structure */
 450   bzero(buf,64);
 451   {
 452     extern int num_good_sends,num_good_receives;
 453     SIVAL(buf,20,num_good_sends);
 454     SIVAL(buf,24,num_good_receives);
 455   }
 456
 457   buf += 46;
 458
 459   /* Send a POSITIVE NAME STATUS RESPONSE */
 460   reply_netbios_packet(p,nmb->header.name_trn_id,
 461                            0,NMB_STATUS,0,True,
 462                        &nmb->question.question_name,
 463                        0x21, 0x01,
 464                        0, rdata,PTR_DIFF(buf,rdata));
 465 }
 466
 467
 468 /***************************************************************************
 469 reply to a name query.
 470
 471 with broadcast name queries:
 472
 473         - only reply if the query is for one of YOUR names. all other machines on
 474           the network will be doing the same thing (that is, only replying to a
 475           broadcast query if they own it)
 476           NOTE: broadcast name queries should only be sent out by a machine
 477           if they HAVEN'T been configured to use WINS. this is generally bad news
 478           in a wide area tcp/ip network and should be rectified by the systems
 479           administrator. USE WINS! :-)
 480         - the exception to this is if the query is for a Primary Domain Controller
 481           type name (0x1b), in which case, a reply is sent.
 482
 483         - NEVER send a negative response to a broadcast query. no-one else will!
 484
 485 with directed name queries:
 486
 487         - if you are the WINS server, you are expected to respond with either
 488       a negative response, a positive response, or a wait-for-acknowledgement
 489       packet, and then later on a pos/neg response.
 490
 491 ****************************************************************************/
 492 void reply_name_query(struct packet_struct *p)
 493 {
 494   struct nmb_packet *nmb = &p->packet.nmb;
 495   struct nmb_name *question = &nmb->question.question_name;
 496   int name_type = question->name_type;
 497   BOOL bcast = nmb->header.nm_flags.bcast;
 498   int ttl=0;
 499   int rcode = 0;
 500   int nb_flags = 0;
 501   struct in_addr retip;
 502   char rdata[6];
 503   struct subnet_record *d = NULL;
 504   BOOL success = True;
 505   struct name_record *n = NULL;
 506
 507   /* directed queries are for WINS server: broadcasts are local SELF queries.
 508      the exception is Domain Master names.  */
 509
 510   int search = bcast ? FIND_LOCAL | FIND_WINS: FIND_WINS;
 511
 512   if (search & FIND_LOCAL)
 513   {
 514     if (!(d = find_req_subnet(p->ip, bcast)))
 515     {
 516       DEBUG(3,("name query: bcast %s not known\n",
 517                                     inet_ntoa(p->ip)));
 518       success = False;
 519     }
 520   }
 521   else
 522   {
 523     if (!(d = wins_subnet))
 524     {
 525       DEBUG(3,("name query: wins search %s not known\n",
 526                                     inet_ntoa(p->ip)));
 527       success = False;
 528     }
 529   }
 530
 531   DEBUG(3,("Name query "));
 532
 533   if (search == 0)
 534   {
 535     /* eh? no criterion for searching database. help! */
 536     success = False;
 537   }
 538
 539   if (!bcast && name_type == 0x1d)
 540   {
 541     /* see WINS manager HELP - 'How WINS Handles Special Names' */
 542     /* a WINS query (unicasted) for a 0x1d name must always return False */
 543     success = False;
 544   }
 545
 546   if (success)
 547   {
 548     /* look up the name in the cache */
 549     n = find_name_search(&d, question, search, p->ip);
 550
 551     /* it is a name that already failed DNS lookup or it's expired */
 552     if (n && (n->source == DNSFAIL ||
 553               (n->death_time && n->death_time < p->timestamp)))
 554     {
 555       success = False;
 556     }
 557
 558     /* do we want to do dns lookups? */
 559     /* XXXX this DELAYS nmbd while it does a search. not a good idea
 560        but there's no pleasant alternative. phil@hands.com suggested
 561        making the name a full DNS name, which would succeed / fail
 562        much quicker.
 563      */
 564     if (success && !n && (lp_wins_proxy() || !bcast))
 565     {
 566       n = dns_name_search(question, p->timestamp);
 567     }
 568   }
 569
 570   if (!n) success = False;
 571
 572   if (success)
 573   {
 574       if (bcast && n->source != SELF && name_type != 0x1b)
 575       {
 576         /* don't respond to broadcast queries unless the query is for
 577            a name we own or it is for a Primary Domain Controller name */
 578
 579             if (!lp_wins_proxy() ||
 580             same_net(p->ip,n->ip_flgs[0].ip,*iface_nmask(p->ip)))
 581         {
 582               /* never reply with a negative response to broadcast queries */
 583               return;
 584             }
 585           }
 586
 587       /* name is directed query, or it's self, or it's a Domain Master type
 588          name, or we're replying on behalf of a caller because they are on a
 589          different subnet and cannot hear the broadcast. XXXX lp_wins_proxy
 590          should be switched off in environments where broadcasts are forwarded
 591        */
 592
 593       /* XXXX note: for proxy servers, we should forward the query on to
 594          another WINS server if the name is not in our database, or we are
 595          not a WINS server ourselves
 596        */
 597       ttl = n->death_time ? n->death_time - p->timestamp : GET_TTL(0);
 598       retip = n->ip_flgs[0].ip;
 599       nb_flags = n->ip_flgs[0].nb_flags;
 600   }
 601
 602   if (!success && bcast) return; /* never reply negative response to bcasts */
 603
 604   /* if the IP is 0 then substitute my IP */
 605   if (zero_ip(retip)) retip = *iface_ip(p->ip);
 606
 607   if (success)
 608   {
 609       rcode = 0;
 610       DEBUG(3,("OK %s\n",inet_ntoa(retip)));
 611   }
 612   else
 613   {
 614       rcode = 3;
 615       DEBUG(3,("UNKNOWN\n"));
 616   }
 617
 618   if (success)
 619   {
 620       rdata[0] = nb_flags;
 621       rdata[1] = 0;
 622       putip(&rdata[2],(char *)&retip);
 623   }
 624
 625   reply_netbios_packet(p,nmb->header.name_trn_id,
 626                            rcode,NMB_QUERY,0,True,
 627                        &nmb->question.question_name,
 628                0x20, 0x01,
 629                        ttl,
 630                        rdata, success ? 6 : 0);
 631 }