source/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, dgram_sock;
  80
  81         /* Check if we are creating a non broadcast subnet - if so don't create
  82                 sockets.  */
  83
  84         if(type != NORMAL_SUBNET) {
  85                 nmb_sock = -1;
  86                 dgram_sock = -1;
  87         } else {
  88                 struct sockaddr_storage ss;
  89
  90                 in_addr_to_sockaddr_storage(&ss, myip);
  91
  92                 /*
  93                  * Attempt to open the sockets on port 137/138 for this interface
  94                  * and bind them.
  95                  * Fail the subnet creation if this fails.
  96                  */
  97
  98                 if((nmb_sock = open_socket_in(SOCK_DGRAM, global_nmb_port,0, &ss,true)) == -1) {
  99                         if( DEBUGLVL( 0 ) ) {
 100                                 Debug1( "nmbd_subnetdb:make_subnet()\n" );
 101                                 Debug1( "  Failed to open nmb socket on interface %s ", inet_ntoa(myip) );
 102                                 Debug1( "for port %d.  ", global_nmb_port );
 103                                 Debug1( "Error was %s\n", strerror(errno) );
 104                         }
 105                         return NULL;
 106                 }
 107
 108                 if((dgram_sock = open_socket_in(SOCK_DGRAM,DGRAM_PORT,3, &ss, true)) == -1) {
 109                         if( DEBUGLVL( 0 ) ) {
 110                                 Debug1( "nmbd_subnetdb:make_subnet()\n" );
 111                                 Debug1( "  Failed to open dgram socket on interface %s ", inet_ntoa(myip) );
 112                                 Debug1( "for port %d.  ", DGRAM_PORT );
 113                                 Debug1( "Error was %s\n", strerror(errno) );
 114                         }
 115                         return NULL;
 116                 }
 117
 118                 /* Make sure we can broadcast from these sockets. */
 119                 set_socket_options(nmb_sock,"SO_BROADCAST");
 120                 set_socket_options(dgram_sock,"SO_BROADCAST");
 121
 122                 /* Set them non-blocking. */
 123                 set_blocking(nmb_sock, False);
 124                 set_blocking(dgram_sock, False);
 125         }
 126
 127         subrec = SMB_MALLOC_P(struct subnet_record);
 128         if (!subrec) {
 129                 DEBUG(0,("make_subnet: malloc fail !\n"));
 130                 if (nmb_sock != -1) {
 131                         close(nmb_sock);
 132                 }
 133                 if (dgram_sock != -1) {
 134                         close(dgram_sock);
 135                 }
 136                 return(NULL);
 137         }
 138
 139         ZERO_STRUCTP(subrec);
 140
 141         if((subrec->subnet_name = SMB_STRDUP(name)) == NULL) {
 142                 DEBUG(0,("make_subnet: malloc fail for subnet name !\n"));
 143                 if (nmb_sock != -1) {
 144                         close(nmb_sock);
 145                 }
 146                 if (dgram_sock != -1) {
 147                         close(dgram_sock);
 148                 }
 149                 ZERO_STRUCTP(subrec);
 150                 SAFE_FREE(subrec);
 151                 return(NULL);
 152         }
 153
 154         DEBUG(2, ("making subnet name:%s ", name ));
 155         DEBUG(2, ("Broadcast address:%s ", inet_ntoa(bcast_ip)));
 156         DEBUG(2, ("Subnet mask:%s\n", inet_ntoa(mask_ip)));
 157
 158         subrec->namelist_changed = False;
 159         subrec->work_changed = False;
 160
 161         subrec->bcast_ip = bcast_ip;
 162         subrec->mask_ip  = mask_ip;
 163         subrec->myip = myip;
 164         subrec->type = type;
 165         subrec->nmb_sock = nmb_sock;
 166         subrec->dgram_sock = dgram_sock;
 167
 168         return subrec;
 169 }
 170
 171 /****************************************************************************
 172   Create a normal subnet
 173 **************************************************************************/
 174
 175 struct subnet_record *make_normal_subnet(const struct interface *iface)
 176 {
 177
 178         struct subnet_record *subrec;
 179         const struct in_addr *pip = &((const struct sockaddr_in *)&iface->ip)->sin_addr;
 180         const struct in_addr *pbcast = &((const struct sockaddr_in *)&iface->bcast)->sin_addr;
 181         const struct in_addr *pnmask = &((const struct sockaddr_in *)&iface->netmask)->sin_addr;
 182
 183         subrec = make_subnet(inet_ntoa(*pip), NORMAL_SUBNET,
 184                              *pip, *pbcast, *pnmask);
 185         if (subrec) {
 186                 add_subnet(subrec);
 187         }
 188         return subrec;
 189 }
 190
 191 /****************************************************************************
 192   Create subnet entries.
 193 **************************************************************************/
 194
 195 bool create_subnets(void)
 196 {
 197         /* We only count IPv4 interfaces whilst we're waiting. */
 198         int num_interfaces = iface_count_v4();
 199         int i;
 200         struct in_addr unicast_ip, ipzero;
 201
 202   try_interfaces_again:
 203
 204         if (iface_count_v4() == 0) {
 205                 DEBUG(0,("create_subnets: No local interfaces !\n"));
 206                 DEBUG(0,("create_subnets: Waiting for an interface to appear ...\n"));
 207         }
 208
 209         /* We only count IPv4 interfaces here. */
 210         while (iface_count_v4() == 0) {
 211                 void (*saved_handler)(int);
 212
 213                 /*
 214                  * Whilst we're waiting for an interface, allow SIGTERM to
 215                  * cause us to exit.
 216                  */
 217
 218                 saved_handler = CatchSignal( SIGTERM, SIGNAL_CAST SIG_DFL );
 219
 220                 sleep(5);
 221                 load_interfaces();
 222
 223                 /*
 224                  * We got an interface, restore our normal term handler.
 225                  */
 226
 227                 CatchSignal( SIGTERM, SIGNAL_CAST saved_handler );
 228         }
 229
 230         /*
 231          * Here we count v4 and v6 - we know there's at least one
 232          * IPv4 interface and we filter on it below.
 233          */
 234         num_interfaces = iface_count();
 235
 236         /*
 237          * Create subnets from all the local interfaces and thread them onto
 238          * the linked list.
 239          */
 240
 241         for (i = 0 ; i < num_interfaces; i++) {
 242                 const struct interface *iface = get_interface(i);
 243
 244                 if (!iface) {
 245                         DEBUG(2,("create_subnets: can't get interface %d.\n", i ));
 246                         continue;
 247                 }
 248
 249                 /* Ensure we're only dealing with IPv4 here. */
 250                 if (iface->ip.ss_family != AF_INET) {
 251                         DEBUG(2,("create_subnets: "
 252                                 "ignoring non IPv4 interface.\n"));
 253                         continue;
 254                 }
 255
 256                 /*
 257                  * We don't want to add a loopback interface, in case
 258                  * someone has added 127.0.0.1 for smbd, nmbd needs to
 259                  * ignore it here. JRA.
 260                  */
 261
 262                 if (is_loopback_addr(&iface->ip)) {
 263                         DEBUG(2,("create_subnets: Ignoring loopback interface.\n" ));
 264                         continue;
 265                 }
 266
 267                 if (!make_normal_subnet(iface))
 268                         return False;
 269         }
 270
 271         /* We must have at least one subnet. */
 272         if (subnetlist == NULL) {
 273                 void (*saved_handler)(int);
 274
 275                 DEBUG(0,("create_subnets: Unable to create any subnet from "
 276                                 "given interfaces. Is your interface line in "
 277                                 "smb.conf correct ?\n"));
 278
 279                 saved_handler = CatchSignal( SIGTERM, SIGNAL_CAST SIG_DFL );
 280
 281                 sleep(5);
 282                 load_interfaces();
 283
 284                 CatchSignal( SIGTERM, SIGNAL_CAST saved_handler );
 285                 goto try_interfaces_again;
 286         }
 287
 288         if (lp_we_are_a_wins_server()) {
 289                 /* Pick the first interface IPv4 address as the WINS server ip. */
 290                 const struct in_addr *nip = first_ipv4_iface();
 291
 292                 if (!nip) {
 293                         return False;
 294                 }
 295
 296                 unicast_ip = *nip;
 297         } else {
 298                 /* note that we do not set the wins server IP here. We just
 299                         set it at zero and let the wins registration code cope
 300                         with getting the IPs right for each packet */
 301                 zero_ip_v4(&unicast_ip);
 302         }
 303
 304         /*
 305          * Create the unicast and remote broadcast subnets.
 306          * Don't put these onto the linked list.
 307          * The ip address of the unicast subnet is set to be
 308          * the WINS server address, if it exists, or ipzero if not.
 309          */
 310
 311         unicast_subnet = make_subnet( "UNICAST_SUBNET", UNICAST_SUBNET,
 312                                 unicast_ip, unicast_ip, unicast_ip);
 313
 314         zero_ip_v4(&ipzero);
 315
 316         remote_broadcast_subnet = make_subnet( "REMOTE_BROADCAST_SUBNET",
 317                                 REMOTE_BROADCAST_SUBNET,
 318                                 ipzero, ipzero, ipzero);
 319
 320         if((unicast_subnet == NULL) || (remote_broadcast_subnet == NULL))
 321                 return False;
 322
 323         /*
 324          * If we are WINS server, create the WINS_SERVER_SUBNET - don't put on
 325          * the linked list.
 326          */
 327
 328         if (lp_we_are_a_wins_server()) {
 329                 if( (wins_server_subnet = make_subnet( "WINS_SERVER_SUBNET",
 330                                                 WINS_SERVER_SUBNET,
 331                                                 ipzero, ipzero, ipzero )) == NULL )
 332                         return False;
 333         }
 334
 335         return True;
 336 }
 337
 338 /*******************************************************************
 339 Function to tell us if we can use the unicast subnet.
 340 ******************************************************************/
 341
 342 bool we_are_a_wins_client(void)
 343 {
 344         if (wins_srv_count() > 0) {
 345                 return True;
 346         }
 347
 348         return False;
 349 }
 350
 351 /*******************************************************************
 352 Access function used by NEXT_SUBNET_INCLUDING_UNICAST
 353 ******************************************************************/
 354
 355 struct subnet_record *get_next_subnet_maybe_unicast(struct subnet_record *subrec)
 356 {
 357         if(subrec == unicast_subnet)
 358                 return NULL;
 359         else if((subrec->next == NULL) && we_are_a_wins_client())
 360                 return unicast_subnet;
 361         else
 362                 return subrec->next;
 363 }
 364
 365 /*******************************************************************
 366  Access function used by retransmit_or_expire_response_records() in
 367  nmbd_packets.c. Patch from Andrey Alekseyev <fetch@muffin.arcadia.spb.ru>
 368  Needed when we need to enumerate all the broadcast, unicast and
 369  WINS subnets.
 370 ******************************************************************/
 371
 372 struct subnet_record *get_next_subnet_maybe_unicast_or_wins_server(struct subnet_record *subrec)
 373 {
 374         if(subrec == unicast_subnet) {
 375                 if(wins_server_subnet)
 376                         return wins_server_subnet;
 377                 else
 378                         return NULL;
 379         }
 380
 381         if(wins_server_subnet && subrec == wins_server_subnet)
 382                 return NULL;
 383
 384         if((subrec->next == NULL) && we_are_a_wins_client())
 385                 return unicast_subnet;
 386         else
 387                 return subrec->next;
 388 }