source3/nmbd/nmbd_become_dmb.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    NBT netbios routines and daemon - version 2
   4    Copyright (C) Andrew Tridgell 1994-1998
   5    Copyright (C) Luke Kenneth Casson Leighton 1994-1998
   6    Copyright (C) Jeremy Allison 1994-2003
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20
  21 */
  22
  23 #include "includes.h"
  24
  25 extern struct in_addr allones_ip;
  26
  27 extern uint16 samba_nb_type; /* Samba's NetBIOS type. */
  28
  29 static void become_domain_master_browser_bcast(const char *);
  30
  31 /****************************************************************************
  32   Fail to become a Domain Master Browser on a subnet.
  33   ****************************************************************************/
  34
  35 static void become_domain_master_fail(struct subnet_record *subrec,
  36                                       struct response_record *rrec,
  37                                       struct nmb_name *fail_name)
  38 {
  39         unstring failname;
  40         struct work_record *work;
  41         struct server_record *servrec;
  42
  43         pull_ascii_nstring(failname, sizeof(failname), fail_name->name);
  44         work = find_workgroup_on_subnet(subrec, failname);
  45         if(!work) {
  46                 DEBUG(0,("become_domain_master_fail: Error - cannot find \
  47 workgroup %s on subnet %s\n", failname, subrec->subnet_name));
  48                 return;
  49         }
  50
  51         /* Set the state back to DOMAIN_NONE. */
  52         work->dom_state = DOMAIN_NONE;
  53
  54         if((servrec = find_server_in_workgroup( work, global_myname())) == NULL) {
  55                 DEBUG(0,("become_domain_master_fail: Error - cannot find server %s \
  56 in workgroup %s on subnet %s\n",
  57                         global_myname(), work->work_group, subrec->subnet_name));
  58                 return;
  59         }
  60
  61         /* Update our server status. */
  62         servrec->serv.type &= ~SV_TYPE_DOMAIN_MASTER;
  63
  64         /* Tell the namelist writer to write out a change. */
  65         subrec->work_changed = True;
  66
  67         DEBUG(0,("become_domain_master_fail: Failed to become a domain master browser for \
  68 workgroup %s on subnet %s. Couldn't register name %s.\n",
  69                 work->work_group, subrec->subnet_name, nmb_namestr(fail_name)));
  70 }
  71
  72 /****************************************************************************
  73   Become a Domain Master Browser on a subnet.
  74   ****************************************************************************/
  75
  76 static void become_domain_master_stage2(struct subnet_record *subrec,
  77                                         struct userdata_struct *userdata,
  78                                         struct nmb_name *registered_name,
  79                                         uint16 nb_flags,
  80                                         int ttl, struct in_addr registered_ip)
  81 {
  82         unstring regname;
  83         struct work_record *work;
  84         struct server_record *servrec;
  85
  86         pull_ascii_nstring(regname, sizeof(regname), registered_name->name);
  87         work = find_workgroup_on_subnet( subrec, regname);
  88
  89         if(!work) {
  90                 DEBUG(0,("become_domain_master_stage2: Error - cannot find \
  91 workgroup %s on subnet %s\n", regname, subrec->subnet_name));
  92                 return;
  93         }
  94
  95         if((servrec = find_server_in_workgroup( work, global_myname())) == NULL) {
  96                 DEBUG(0,("become_domain_master_stage2: Error - cannot find server %s \
  97 in workgroup %s on subnet %s\n",
  98                 global_myname(), regname, subrec->subnet_name));
  99                 work->dom_state = DOMAIN_NONE;
 100                 return;
 101         }
 102
 103         /* Set the state in the workgroup structure. */
 104         work->dom_state = DOMAIN_MST; /* Become domain master. */
 105
 106         /* Update our server status. */
 107         servrec->serv.type |= (SV_TYPE_NT|SV_TYPE_DOMAIN_MASTER);
 108
 109         /* Tell the namelist writer to write out a change. */
 110         subrec->work_changed = True;
 111
 112         if( DEBUGLVL( 0 ) ) {
 113                 dbgtext( "*****\n\nSamba server %s ", global_myname() );
 114                 dbgtext( "is now a domain master browser for " );
 115                 dbgtext( "workgroup %s ", work->work_group );
 116                 dbgtext( "on subnet %s\n\n*****\n", subrec->subnet_name );
 117         }
 118
 119         if( subrec == unicast_subnet ) {
 120                 struct nmb_name nmbname;
 121                 struct in_addr my_first_ip;
 122                 struct in_addr *nip;
 123
 124                 /* Put our name and first IP address into the
 125                    workgroup struct as domain master browser. This
 126                    will stop us syncing with ourself if we are also
 127                    a local master browser. */
 128
 129                 make_nmb_name(&nmbname, global_myname(), 0x20);
 130
 131                 work->dmb_name = nmbname;
 132                 /* Pick the first interface ip address as the domain master browser ip. */
 133                 nip = iface_n_ip(0);
 134
 135                 if (!nip) {
 136                         DEBUG(0,("become_domain_master_stage2: Error. iface_n_ip returned NULL\n"));
 137                         return;
 138                 }
 139
 140                 my_first_ip = *nip;
 141
 142                 putip((char *)&work->dmb_addr, &my_first_ip);
 143
 144                 /* We successfully registered by unicast with the
 145                    WINS server.  We now expect to become the domain
 146                    master on the local subnets. If this fails, it's
 147                    probably a 1.9.16p2 to 1.9.16p11 server's fault.
 148
 149                    This is a configuration issue that should be addressed
 150                    by the network administrator - you shouldn't have
 151                    several machines configured as a domain master browser
 152                    for the same WINS scope (except if they are 1.9.17 or
 153                    greater, and you know what you're doing.
 154
 155                    see docs/DOMAIN.txt.
 156
 157                 */
 158                 become_domain_master_browser_bcast(work->work_group);
 159         } else {
 160                 /*
 161                  * Now we are a domain master on a broadcast subnet, we need to add
 162                  * the WORKGROUP<1b> name to the unicast subnet so that we can answer
 163                  * unicast requests sent to this name. This bug wasn't found for a while
 164                  * as it is strange to have a DMB without using WINS. JRA.
 165                  */
 166                 insert_permanent_name_into_unicast(subrec, registered_name, nb_flags);
 167         }
 168 }
 169
 170 /****************************************************************************
 171   Start the name registration process when becoming a Domain Master Browser
 172   on a subnet.
 173 ****************************************************************************/
 174
 175 static void become_domain_master_stage1(struct subnet_record *subrec, const char *wg_name)
 176 {
 177         struct work_record *work;
 178
 179         DEBUG(2,("become_domain_master_stage1: Becoming domain master browser for \
 180 workgroup %s on subnet %s\n", wg_name, subrec->subnet_name));
 181
 182         /* First, find the workgroup on the subnet. */
 183         if((work = find_workgroup_on_subnet( subrec, wg_name )) == NULL) {
 184                 DEBUG(0,("become_domain_master_stage1: Error - unable to find workgroup %s on subnet %s.\n",
 185                         wg_name, subrec->subnet_name));
 186                 return;
 187         }
 188
 189         DEBUG(3,("become_domain_master_stage1: go to first stage: register <1b> name\n"));
 190         work->dom_state = DOMAIN_WAIT;
 191
 192         /* WORKGROUP<1b> is the domain master browser name. */
 193         register_name(subrec, work->work_group,0x1b,samba_nb_type,
 194                         become_domain_master_stage2,
 195                         become_domain_master_fail, NULL);
 196 }
 197
 198 /****************************************************************************
 199   Function called when a query for a WORKGROUP<1b> name succeeds.
 200   This is normally a fail condition as it means there is already
 201   a domain master browser for a workgroup and we were trying to
 202   become one.
 203 ****************************************************************************/
 204
 205 static void become_domain_master_query_success(struct subnet_record *subrec,
 206                         struct userdata_struct *userdata,
 207                         struct nmb_name *nmbname, struct in_addr ip,
 208                         struct res_rec *rrec)
 209 {
 210         unstring name;
 211         pull_ascii_nstring(name, sizeof(name), nmbname->name);
 212
 213         /* If the given ip is not ours, then we can't become a domain
 214                 controler as the name is already registered.
 215         */
 216
 217         /* BUG note. Samba 1.9.16p11 servers seem to return the broadcast
 218                 address or zero ip for this query. Pretend this is ok. */
 219
 220         if(ismyip(ip) || ip_equal(allones_ip, ip) || is_zero_ip(ip)) {
 221                 if( DEBUGLVL( 3 ) ) {
 222                         dbgtext( "become_domain_master_query_success():\n" );
 223                         dbgtext( "Our address (%s) ", inet_ntoa(ip) );
 224                         dbgtext( "returned in query for name %s ", nmb_namestr(nmbname) );
 225                         dbgtext( "(domain master browser name) " );
 226                         dbgtext( "on subnet %s.\n", subrec->subnet_name );
 227                         dbgtext( "Continuing with domain master code.\n" );
 228                 }
 229
 230                 become_domain_master_stage1(subrec, name);
 231         } else {
 232                 if( DEBUGLVL( 0 ) ) {
 233                         dbgtext( "become_domain_master_query_success:\n" );
 234                         dbgtext( "There is already a domain master browser at " );
 235                         dbgtext( "IP %s for workgroup %s ", inet_ntoa(ip), name );
 236                         dbgtext( "registered on subnet %s.\n", subrec->subnet_name );
 237                 }
 238         }
 239 }
 240
 241 /****************************************************************************
 242   Function called when a query for a WORKGROUP<1b> name fails.
 243   This is normally a success condition as it then allows us to register
 244   our own Domain Master Browser name.
 245   ****************************************************************************/
 246
 247 static void become_domain_master_query_fail(struct subnet_record *subrec,
 248                                     struct response_record *rrec,
 249                                     struct nmb_name *question_name, int fail_code)
 250 {
 251         unstring name;
 252
 253         /* If the query was unicast, and the error is not NAM_ERR (name didn't exist),
 254                 then this is a failure. Otherwise, not finding the name is what we want. */
 255
 256         if((subrec == unicast_subnet) && (fail_code != NAM_ERR)) {
 257                 DEBUG(0,("become_domain_master_query_fail: Error %d returned when \
 258 querying WINS server for name %s.\n",
 259                         fail_code, nmb_namestr(question_name)));
 260                 return;
 261         }
 262
 263         /* Otherwise - not having the name allows us to register it. */
 264         pull_ascii_nstring(name, sizeof(name), question_name->name);
 265         become_domain_master_stage1(subrec, name);
 266 }
 267
 268 /****************************************************************************
 269   Attempt to become a domain master browser on all broadcast subnets.
 270   ****************************************************************************/
 271
 272 static void become_domain_master_browser_bcast(const char *workgroup_name)
 273 {
 274         struct subnet_record *subrec;
 275
 276         for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) {
 277                 struct work_record *work = find_workgroup_on_subnet(subrec, workgroup_name);
 278
 279                 if (work && (work->dom_state == DOMAIN_NONE)) {
 280                         struct nmb_name nmbname;
 281                         make_nmb_name(&nmbname,workgroup_name,0x1b);
 282
 283                         /*
 284                          * Check for our name on the given broadcast subnet first, only initiate
 285                          * further processing if we cannot find it.
 286                          */
 287
 288                         if (find_name_on_subnet(subrec, &nmbname, FIND_SELF_NAME) == NULL) {
 289                                 if( DEBUGLVL( 0 ) ) {
 290                                         dbgtext( "become_domain_master_browser_bcast:\n" );
 291                                         dbgtext( "Attempting to become domain master browser on " );
 292                                         dbgtext( "workgroup %s on subnet %s\n",
 293                                                 workgroup_name, subrec->subnet_name );
 294                                 }
 295
 296                                 /* Send out a query to establish whether there's a
 297                                    domain controller on the local subnet. If not,
 298                                    we can become a domain controller.
 299                                 */
 300
 301                                 DEBUG(0,("become_domain_master_browser_bcast: querying subnet %s \
 302 for domain master browser on workgroup %s\n", subrec->subnet_name, workgroup_name));
 303
 304                                 query_name(subrec, workgroup_name, nmbname.name_type,
 305                                         become_domain_master_query_success,
 306                                         become_domain_master_query_fail,
 307                                         NULL);
 308                         }
 309                 }
 310         }
 311 }
 312
 313 /****************************************************************************
 314   Attempt to become a domain master browser by registering with WINS.
 315   ****************************************************************************/
 316
 317 static void become_domain_master_browser_wins(const char *workgroup_name)
 318 {
 319         struct work_record *work;
 320
 321         work = find_workgroup_on_subnet(unicast_subnet, workgroup_name);
 322
 323         if (work && (work->dom_state == DOMAIN_NONE)) {
 324                 struct nmb_name nmbname;
 325
 326                 make_nmb_name(&nmbname,workgroup_name,0x1b);
 327
 328                 /*
 329                  * Check for our name on the unicast subnet first, only initiate
 330                  * further processing if we cannot find it.
 331                  */
 332
 333                 if (find_name_on_subnet(unicast_subnet, &nmbname, FIND_SELF_NAME) == NULL) {
 334                         if( DEBUGLVL( 0 ) ) {
 335                                 dbgtext( "become_domain_master_browser_wins:\n" );
 336                                 dbgtext( "Attempting to become domain master browser " );
 337                                 dbgtext( "on workgroup %s, subnet %s.\n",
 338                                         workgroup_name, unicast_subnet->subnet_name );
 339                         }
 340
 341                         /* Send out a query to establish whether there's a
 342                            domain master broswer registered with WINS. If not,
 343                            we can become a domain master browser.
 344                         */
 345
 346                         DEBUG(0,("become_domain_master_browser_wins: querying WINS server from IP %s \
 347 for domain master browser name %s on workgroup %s\n",
 348                                 inet_ntoa(unicast_subnet->myip), nmb_namestr(&nmbname), workgroup_name));
 349
 350                         query_name(unicast_subnet, workgroup_name, nmbname.name_type,
 351                                 become_domain_master_query_success,
 352                                 become_domain_master_query_fail,
 353                                 NULL);
 354                 }
 355         }
 356 }
 357
 358 /****************************************************************************
 359   Add the domain logon server and domain master browser names
 360   if we are set up to do so.
 361   **************************************************************************/
 362
 363 void add_domain_names(time_t t)
 364 {
 365         static time_t lastrun = 0;
 366
 367         if ((lastrun != 0) && (t < lastrun + (CHECK_TIME_ADD_DOM_NAMES * 60)))
 368                 return;
 369
 370         lastrun = t;
 371
 372         /* Do the "internet group" - <1c> names. */
 373         if (lp_domain_logons())
 374                 add_logon_names();
 375
 376         /* Do the domain master names. */
 377         if(lp_domain_master()) {
 378                 if(we_are_a_wins_client()) {
 379                         /* We register the WORKGROUP<1b> name with the WINS
 380                                 server first, and call add_domain_master_bcast()
 381                                 only if this is successful.
 382
 383                                 This results in domain logon services being gracefully provided,
 384                                 as opposed to the aggressive nature of 1.9.16p2 to 1.9.16p11.
 385                                 1.9.16p2 to 1.9.16p11 - due to a bug in namelogon.c,
 386                                 cannot provide domain master / domain logon services.
 387                         */
 388                         become_domain_master_browser_wins(lp_workgroup());
 389                 } else {
 390                         become_domain_master_browser_bcast(lp_workgroup());
 391                 }
 392         }
 393 }