source3/nmbd/nmbd_subnetdb.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 1994-1998
   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    Revision History:
  22
  23 */
  24
  25 #include "includes.h"
  26
  27 extern int global_nmb_port;
  28
  29 /* This is the broadcast subnets database. */
  30 struct subnet_record *subnetlist = NULL;
  31
  32 /* Extra subnets - keep these separate so enumeration code doesn't
  33    run onto it by mistake. */
  34
  35 struct subnet_record *unicast_subnet = NULL;
  36 struct subnet_record *remote_broadcast_subnet = NULL;
  37 struct subnet_record *wins_server_subnet = NULL;
  38
  39 extern uint16 samba_nb_type; /* Samba's NetBIOS name type. */
  40
  41 /****************************************************************************
  42   Add a subnet into the list.
  43   **************************************************************************/
  44
  45 static void add_subnet(struct subnet_record *subrec)
  46 {
  47         DLIST_ADD(subnetlist, subrec);
  48 }
  49
  50 /****************************************************************************
  51 stop listening on a subnet
  52 we don't free the record as we don't have proper reference counting for it
  53 yet and it may be in use by a response record
  54   ****************************************************************************/
  55
  56 void close_subnet(struct subnet_record *subrec)
  57 {
  58         if (subrec->dgram_sock != -1) {
  59                 close(subrec->dgram_sock);
  60                 subrec->dgram_sock = -1;
  61         }
  62         if (subrec->nmb_sock != -1) {
  63                 close(subrec->nmb_sock);
  64                 subrec->nmb_sock = -1;
  65         }
  66
  67         DLIST_REMOVE(subnetlist, subrec);
  68 }
  69
  70 /****************************************************************************
  71   Create a subnet entry.
  72   ****************************************************************************/
  73
  74 static struct subnet_record *make_subnet(const char *name, enum subnet_type type,
  75                                          struct in_addr myip, struct in_addr bcast_ip,
  76                                          struct in_addr mask_ip)
  77 {
  78         struct subnet_record *subrec = NULL;
  79         int nmb_sock = -1;
  80         int dgram_sock = -1;
  81         int nmb_bcast = -1;
  82         int dgram_bcast = -1;
  83         bool bind_bcast = lp_nmbd_bind_explicit_broadcast();
  84
  85         /* Check if we are creating a non broadcast subnet - if so don't create
  86                 sockets.  */
  87
  88         if (type == NORMAL_SUBNET) {
  89                 struct sockaddr_storage ss;
  90                 struct sockaddr_storage ss_bcast;
  91
  92                 in_addr_to_sockaddr_storage(&ss, myip);
  93                 in_addr_to_sockaddr_storage(&ss_bcast, bcast_ip);
  94
  95                 /*
  96                  * Attempt to open the sockets on port 137/138 for this interface
  97                  * and bind them.
  98                  * Fail the subnet creation if this fails.
  99                  */
 100
 101                 nmb_sock = open_socket_in(SOCK_DGRAM, global_nmb_port,
 102                                           0, &ss, true);
 103                 if (nmb_sock == -1) {
 104                         DEBUG(0,   ("nmbd_subnetdb:make_subnet()\n"));
 105                         DEBUGADD(0,("  Failed to open nmb socket on interface %s ",
 106                                     inet_ntoa(myip)));
 107                         DEBUGADD(0,("for port %d.  ", global_nmb_port));
 108                         DEBUGADD(0,("Error was %s\n", strerror(errno)));
 109                         goto failed;
 110                 }
 111                 set_socket_options(nmb_sock,"SO_BROADCAST");
 112                 set_blocking(nmb_sock, false);
 113
 114                 if (bind_bcast) {
 115                         nmb_bcast = open_socket_in(SOCK_DGRAM, global_nmb_port,
 116                                                    0, &ss_bcast, true);
 117                         if (nmb_bcast == -1) {
 118                                 DEBUG(0,   ("nmbd_subnetdb:make_subnet()\n"));
 119                                 DEBUGADD(0,("  Failed to open nmb bcast socket on interface %s ",
 120                                             inet_ntoa(bcast_ip)));
 121                                 DEBUGADD(0,("for port %d.  ", global_nmb_port));
 122                                 DEBUGADD(0,("Error was %s\n", strerror(errno)));
 123                                 goto failed;
 124                         }
 125                         set_socket_options(nmb_bcast, "SO_BROADCAST");
 126                         set_blocking(nmb_bcast, false);
 127                 }
 128
 129                 dgram_sock = open_socket_in(SOCK_DGRAM, DGRAM_PORT,
 130                                             3, &ss, true);
 131                 if (dgram_sock == -1) {
 132                         DEBUG(0,   ("nmbd_subnetdb:make_subnet()\n"));
 133                         DEBUGADD(0,("  Failed to open dgram socket on interface %s ",
 134                                     inet_ntoa(myip)));
 135                         DEBUGADD(0,("for port %d.  ", DGRAM_PORT));
 136                         DEBUGADD(0,("Error was %s\n", strerror(errno)));
 137                         goto failed;
 138                 }
 139                 set_socket_options(dgram_sock, "SO_BROADCAST");
 140                 set_blocking(dgram_sock, false);
 141
 142                 if (bind_bcast) {
 143                         dgram_bcast = open_socket_in(SOCK_DGRAM, DGRAM_PORT,
 144                                                      3, &ss_bcast, true);
 145                         if (dgram_bcast == -1) {
 146                                 DEBUG(0,   ("nmbd_subnetdb:make_subnet()\n"));
 147                                 DEBUGADD(0,("  Failed to open dgram bcast socket on interface %s ",
 148                                             inet_ntoa(bcast_ip)));
 149                                 DEBUGADD(0,("for port %d.  ", DGRAM_PORT));
 150                                 DEBUGADD(0,("Error was %s\n", strerror(errno)));
 151                                 goto failed;
 152                         }
 153                         set_socket_options(dgram_bcast, "SO_BROADCAST");
 154                         set_blocking(dgram_bcast, false);
 155                 }
 156         }
 157
 158         subrec = SMB_MALLOC_P(struct subnet_record);
 159         if (!subrec) {
 160                 DEBUG(0,("make_subnet: malloc fail !\n"));
 161                 goto failed;
 162         }
 163
 164         ZERO_STRUCTP(subrec);
 165
 166         if((subrec->subnet_name = SMB_STRDUP(name)) == NULL) {
 167                 DEBUG(0,("make_subnet: malloc fail for subnet name !\n"));
 168                 goto failed;
 169         }
 170
 171         DEBUG(2, ("making subnet name:%s ", name ));
 172         DEBUG(2, ("Broadcast address:%s ", inet_ntoa(bcast_ip)));
 173         DEBUG(2, ("Subnet mask:%s\n", inet_ntoa(mask_ip)));
 174
 175         subrec->namelist_changed = False;
 176         subrec->work_changed = False;
 177
 178         subrec->bcast_ip = bcast_ip;
 179         subrec->mask_ip  = mask_ip;
 180         subrec->myip = myip;
 181         subrec->type = type;
 182         subrec->nmb_sock = nmb_sock;
 183         subrec->nmb_bcast = nmb_bcast;
 184         subrec->dgram_sock = dgram_sock;
 185         subrec->dgram_bcast = dgram_bcast;
 186
 187         return subrec;
 188
 189 failed:
 190         SAFE_FREE(subrec);
 191         if (nmb_sock != -1) {
 192                 close(nmb_sock);
 193         }
 194         if (nmb_bcast != -1) {
 195                 close(nmb_bcast);
 196         }
 197         if (dgram_sock != -1) {
 198                 close(dgram_sock);
 199         }
 200         if (dgram_bcast != -1) {
 201                 close(dgram_bcast);
 202         }
 203         return NULL;
 204 }
 205
 206 /****************************************************************************
 207   Create a normal subnet
 208 **************************************************************************/
 209
 210 struct subnet_record *make_normal_subnet(const struct interface *iface)
 211 {
 212
 213         struct subnet_record *subrec;
 214         const struct in_addr *pip = &((const struct sockaddr_in *)&iface->ip)->sin_addr;
 215         const struct in_addr *pbcast = &((const struct sockaddr_in *)&iface->bcast)->sin_addr;
 216         const struct in_addr *pnmask = &((const struct sockaddr_in *)&iface->netmask)->sin_addr;
 217
 218         subrec = make_subnet(inet_ntoa(*pip), NORMAL_SUBNET,
 219                              *pip, *pbcast, *pnmask);
 220         if (subrec) {
 221                 add_subnet(subrec);
 222         }
 223         return subrec;
 224 }
 225
 226 /****************************************************************************
 227   Create subnet entries.
 228 **************************************************************************/
 229
 230 bool create_subnets(void)
 231 {
 232         /* We only count IPv4 interfaces whilst we're waiting. */
 233         int num_interfaces;
 234         int i;
 235         struct in_addr unicast_ip, ipzero;
 236
 237   try_interfaces_again:
 238
 239         /* Only count IPv4, non-loopback interfaces. */
 240         if (iface_count_v4_nl() == 0) {
 241                 DEBUG(0,("create_subnets: No local IPv4 non-loopback interfaces !\n"));
 242                 DEBUG(0,("create_subnets: Waiting for an interface to appear ...\n"));
 243         }
 244
 245         /* We only count IPv4, non-loopback interfaces here. */
 246         while (iface_count_v4_nl() == 0) {
 247                 void (*saved_handler)(int);
 248
 249                 /*
 250                  * Whilst we're waiting for an interface, allow SIGTERM to
 251                  * cause us to exit.
 252                  */
 253
 254                 saved_handler = CatchSignal(SIGTERM, SIG_DFL);
 255
 256                 sleep(5);
 257                 load_interfaces();
 258
 259                 /*
 260                  * We got an interface, restore our normal term handler.
 261                  */
 262
 263                 CatchSignal(SIGTERM, saved_handler);
 264         }
 265
 266         /*
 267          * Here we count v4 and v6 - we know there's at least one
 268          * IPv4 interface and we filter on it below.
 269          */
 270         num_interfaces = iface_count();
 271
 272         /*
 273          * Create subnets from all the local interfaces and thread them onto
 274          * the linked list.
 275          */
 276
 277         for (i = 0 ; i < num_interfaces; i++) {
 278                 const struct interface *iface = get_interface(i);
 279
 280                 if (!iface) {
 281                         DEBUG(2,("create_subnets: can't get interface %d.\n", i ));
 282                         continue;
 283                 }
 284
 285                 /* Ensure we're only dealing with IPv4 here. */
 286                 if (iface->ip.ss_family != AF_INET) {
 287                         DEBUG(2,("create_subnets: "
 288                                 "ignoring non IPv4 interface.\n"));
 289                         continue;
 290                 }
 291
 292                 /*
 293                  * We don't want to add a loopback interface, in case
 294                  * someone has added 127.0.0.1 for smbd, nmbd needs to
 295                  * ignore it here. JRA.
 296                  */
 297
 298                 if (is_loopback_addr((struct sockaddr *)&iface->ip)) {
 299                         DEBUG(2,("create_subnets: Ignoring loopback interface.\n" ));
 300                         continue;
 301                 }
 302
 303                 if (!make_normal_subnet(iface))
 304                         return False;
 305         }
 306
 307         /* We must have at least one subnet. */
 308         if (subnetlist == NULL) {
 309                 void (*saved_handler)(int);
 310
 311                 DEBUG(0,("create_subnets: Unable to create any subnet from "
 312                                 "given interfaces. Is your interface line in "
 313                                 "smb.conf correct ?\n"));
 314
 315                 saved_handler = CatchSignal(SIGTERM, SIG_DFL);
 316
 317                 sleep(5);
 318                 load_interfaces();
 319
 320                 CatchSignal(SIGTERM, saved_handler);
 321                 goto try_interfaces_again;
 322         }
 323
 324         if (lp_we_are_a_wins_server()) {
 325                 /* Pick the first interface IPv4 address as the WINS server
 326                  * ip. */
 327                 const struct in_addr *nip = first_ipv4_iface();
 328
 329                 if (!nip) {
 330                         return False;
 331                 }
 332
 333                 unicast_ip = *nip;
 334         } else {
 335                 /* note that we do not set the wins server IP here. We just
 336                         set it at zero and let the wins registration code cope
 337                         with getting the IPs right for each packet */
 338                 zero_ip_v4(&unicast_ip);
 339         }
 340
 341         /*
 342          * Create the unicast and remote broadcast subnets.
 343          * Don't put these onto the linked list.
 344          * The ip address of the unicast subnet is set to be
 345          * the WINS server address, if it exists, or ipzero if not.
 346          */
 347
 348         unicast_subnet = make_subnet( "UNICAST_SUBNET", UNICAST_SUBNET,
 349                                 unicast_ip, unicast_ip, unicast_ip);
 350
 351         zero_ip_v4(&ipzero);
 352
 353         remote_broadcast_subnet = make_subnet( "REMOTE_BROADCAST_SUBNET",
 354                                 REMOTE_BROADCAST_SUBNET,
 355                                 ipzero, ipzero, ipzero);
 356
 357         if((unicast_subnet == NULL) || (remote_broadcast_subnet == NULL))
 358                 return False;
 359
 360         /*
 361          * If we are WINS server, create the WINS_SERVER_SUBNET - don't put on
 362          * the linked list.
 363          */
 364
 365         if (lp_we_are_a_wins_server()) {
 366                 if( (wins_server_subnet = make_subnet( "WINS_SERVER_SUBNET",
 367                                                 WINS_SERVER_SUBNET,
 368                                                 ipzero, ipzero, ipzero )) == NULL )
 369                         return False;
 370         }
 371
 372         return True;
 373 }
 374
 375 /*******************************************************************
 376 Function to tell us if we can use the unicast subnet.
 377 ******************************************************************/
 378
 379 bool we_are_a_wins_client(void)
 380 {
 381         if (wins_srv_count() > 0) {
 382                 return True;
 383         }
 384
 385         return False;
 386 }
 387
 388 /*******************************************************************
 389 Access function used by NEXT_SUBNET_INCLUDING_UNICAST
 390 ******************************************************************/
 391
 392 struct subnet_record *get_next_subnet_maybe_unicast(struct subnet_record *subrec)
 393 {
 394         if(subrec == unicast_subnet)
 395                 return NULL;
 396         else if((subrec->next == NULL) && we_are_a_wins_client())
 397                 return unicast_subnet;
 398         else
 399                 return subrec->next;
 400 }
 401
 402 /*******************************************************************
 403  Access function used by retransmit_or_expire_response_records() in
 404  nmbd_packets.c. Patch from Andrey Alekseyev <fetch@muffin.arcadia.spb.ru>
 405  Needed when we need to enumerate all the broadcast, unicast and
 406  WINS subnets.
 407 ******************************************************************/
 408
 409 struct subnet_record *get_next_subnet_maybe_unicast_or_wins_server(struct subnet_record *subrec)
 410 {
 411         if(subrec == unicast_subnet) {
 412                 if(wins_server_subnet)
 413                         return wins_server_subnet;
 414                 else
 415                         return NULL;
 416         }
 417
 418         if(wins_server_subnet && subrec == wins_server_subnet)
 419                 return NULL;
 420
 421         if((subrec->next == NULL) && we_are_a_wins_client())
 422                 return unicast_subnet;
 423         else
 424                 return subrec->next;
 425 }