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, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22    Revision History:
  23
  24 */
  25
  26 #include "includes.h"
  27
  28 extern struct in_addr loopback_ip;
  29 extern int global_nmb_port;
  30
  31 /* This is the broadcast subnets database. */
  32 struct subnet_record *subnetlist = NULL;
  33
  34 /* Extra subnets - keep these separate so enumeration code doesn't
  35    run onto it by mistake. */
  36
  37 struct subnet_record *unicast_subnet = NULL;
  38 struct subnet_record *remote_broadcast_subnet = NULL;
  39 struct subnet_record *wins_server_subnet = NULL;
  40
  41 extern uint16 samba_nb_type; /* Samba's NetBIOS name type. */
  42
  43 /****************************************************************************
  44   Add a subnet into the list.
  45   **************************************************************************/
  46
  47 static void add_subnet(struct subnet_record *subrec)
  48 {
  49         DLIST_ADD(subnetlist, subrec);
  50 }
  51
  52 /****************************************************************************
  53 stop listening on a subnet
  54 we don't free the record as we don't have proper reference counting for it
  55 yet and it may be in use by a response record
  56   ****************************************************************************/
  57
  58 void close_subnet(struct subnet_record *subrec)
  59 {
  60         if (subrec->dgram_sock != -1) {
  61                 close(subrec->dgram_sock);
  62                 subrec->dgram_sock = -1;
  63         }
  64         if (subrec->nmb_sock != -1) {
  65                 close(subrec->nmb_sock);
  66                 subrec->nmb_sock = -1;
  67         }
  68
  69         DLIST_REMOVE(subnetlist, subrec);
  70 }
  71
  72 /****************************************************************************
  73   Create a subnet entry.
  74   ****************************************************************************/
  75
  76 static struct subnet_record *make_subnet(const char *name, enum subnet_type type,
  77                                          struct in_addr myip, struct in_addr bcast_ip,
  78                                          struct in_addr mask_ip)
  79 {
  80         struct subnet_record *subrec = NULL;
  81         int nmb_sock, dgram_sock;
  82
  83         /* Check if we are creating a non broadcast subnet - if so don't create
  84                 sockets.  */
  85
  86         if(type != NORMAL_SUBNET) {
  87                 nmb_sock = -1;
  88                 dgram_sock = -1;
  89         } else {
  90                 /*
  91                  * Attempt to open the sockets on port 137/138 for this interface
  92                  * and bind them.
  93                  * Fail the subnet creation if this fails.
  94                  */
  95
  96                 if((nmb_sock = open_socket_in(SOCK_DGRAM, global_nmb_port,0, myip.s_addr,True)) == -1) {
  97                         if( DEBUGLVL( 0 ) ) {
  98                                 Debug1( "nmbd_subnetdb:make_subnet()\n" );
  99                                 Debug1( "  Failed to open nmb socket on interface %s ", inet_ntoa(myip) );
 100                                 Debug1( "for port %d.  ", global_nmb_port );
 101                                 Debug1( "Error was %s\n", strerror(errno) );
 102                         }
 103                         return NULL;
 104                 }
 105
 106                 if((dgram_sock = open_socket_in(SOCK_DGRAM,DGRAM_PORT,3, myip.s_addr,True)) == -1) {
 107                         if( DEBUGLVL( 0 ) ) {
 108                                 Debug1( "nmbd_subnetdb:make_subnet()\n" );
 109                                 Debug1( "  Failed to open dgram socket on interface %s ", inet_ntoa(myip) );
 110                                 Debug1( "for port %d.  ", DGRAM_PORT );
 111                                 Debug1( "Error was %s\n", strerror(errno) );
 112                         }
 113                         return NULL;
 114                 }
 115
 116                 /* Make sure we can broadcast from these sockets. */
 117                 set_socket_options(nmb_sock,"SO_BROADCAST");
 118                 set_socket_options(dgram_sock,"SO_BROADCAST");
 119
 120                 /* Set them non-blocking. */
 121                 set_blocking(nmb_sock, False);
 122                 set_blocking(dgram_sock, False);
 123         }
 124
 125         subrec = SMB_MALLOC_P(struct subnet_record);
 126         if (!subrec) {
 127                 DEBUG(0,("make_subnet: malloc fail !\n"));
 128                 close(nmb_sock);
 129                 close(dgram_sock);
 130                 return(NULL);
 131         }
 132
 133         ZERO_STRUCTP(subrec);
 134
 135         if((subrec->subnet_name = SMB_STRDUP(name)) == NULL) {
 136                 DEBUG(0,("make_subnet: malloc fail for subnet name !\n"));
 137                 close(nmb_sock);
 138                 close(dgram_sock);
 139                 ZERO_STRUCTP(subrec);
 140                 SAFE_FREE(subrec);
 141                 return(NULL);
 142         }
 143
 144         DEBUG(2, ("making subnet name:%s ", name ));
 145         DEBUG(2, ("Broadcast address:%s ", inet_ntoa(bcast_ip)));
 146         DEBUG(2, ("Subnet mask:%s\n", inet_ntoa(mask_ip)));
 147
 148         subrec->namelist_changed = False;
 149         subrec->work_changed = False;
 150
 151         subrec->bcast_ip = bcast_ip;
 152         subrec->mask_ip  = mask_ip;
 153         subrec->myip = myip;
 154         subrec->type = type;
 155         subrec->nmb_sock = nmb_sock;
 156         subrec->dgram_sock = dgram_sock;
 157
 158         return subrec;
 159 }
 160
 161 /****************************************************************************
 162   Create a normal subnet
 163 **************************************************************************/
 164
 165 struct subnet_record *make_normal_subnet(struct interface *iface)
 166 {
 167         struct subnet_record *subrec;
 168
 169         subrec = make_subnet(inet_ntoa(iface->ip), NORMAL_SUBNET,
 170                              iface->ip, iface->bcast, iface->nmask);
 171         if (subrec) {
 172                 add_subnet(subrec);
 173         }
 174         return subrec;
 175 }
 176
 177 /****************************************************************************
 178   Create subnet entries.
 179 **************************************************************************/
 180
 181 BOOL create_subnets(void)
 182 {
 183         int num_interfaces = iface_count();
 184         int i;
 185         struct in_addr unicast_ip, ipzero;
 186
 187         if(num_interfaces == 0) {
 188                 void (*saved_handler)(int);
 189
 190                 DEBUG(0,("create_subnets: No local interfaces !\n"));
 191                 DEBUG(0,("create_subnets: Waiting for an interface to appear ...\n"));
 192
 193                 /*
 194                  * Whilst we're waiting for an interface, allow SIGTERM to
 195                  * cause us to exit.
 196                  */
 197
 198                 saved_handler = CatchSignal( SIGTERM, SIGNAL_CAST SIG_DFL );
 199
 200                 while (iface_count() == 0) {
 201                         sleep(5);
 202                         load_interfaces();
 203                 }
 204
 205                 /*
 206                  * We got an interface, restore our normal term handler.
 207                  */
 208
 209                 CatchSignal( SIGTERM, SIGNAL_CAST saved_handler );
 210         }
 211
 212         num_interfaces = iface_count();
 213
 214         /*
 215          * Create subnets from all the local interfaces and thread them onto
 216          * the linked list.
 217          */
 218
 219         for (i = 0 ; i < num_interfaces; i++) {
 220                 struct interface *iface = get_interface(i);
 221
 222                 if (!iface) {
 223                         DEBUG(2,("create_subnets: can't get interface %d.\n", i ));
 224                         continue;
 225                 }
 226
 227                 /*
 228                  * We don't want to add a loopback interface, in case
 229                  * someone has added 127.0.0.1 for smbd, nmbd needs to
 230                  * ignore it here. JRA.
 231                  */
 232
 233                 if (ip_equal(iface->ip, loopback_ip)) {
 234                         DEBUG(2,("create_subnets: Ignoring loopback interface.\n" ));
 235                         continue;
 236                 }
 237
 238                 if (!make_normal_subnet(iface))
 239                         return False;
 240         }
 241
 242         /* We must have at least one subnet. */
 243         if (subnetlist == NULL) {
 244                 DEBUG(0,("create_subnets: unable to create any subnet from "
 245                                 "given interfaces. nmbd is terminating\n"));
 246                 return False;
 247         }
 248
 249         if (lp_we_are_a_wins_server()) {
 250                 /* Pick the first interface ip address as the WINS server ip. */
 251                 struct in_addr *nip = iface_n_ip(0);
 252
 253                 if (!nip) {
 254                         return False;
 255                 }
 256
 257                 unicast_ip = *nip;
 258         } else {
 259                 /* note that we do not set the wins server IP here. We just
 260                         set it at zero and let the wins registration code cope
 261                         with getting the IPs right for each packet */
 262                 zero_ip(&unicast_ip);
 263         }
 264
 265         /*
 266          * Create the unicast and remote broadcast subnets.
 267          * Don't put these onto the linked list.
 268          * The ip address of the unicast subnet is set to be
 269          * the WINS server address, if it exists, or ipzero if not.
 270          */
 271
 272         unicast_subnet = make_subnet( "UNICAST_SUBNET", UNICAST_SUBNET,
 273                                 unicast_ip, unicast_ip, unicast_ip);
 274
 275         zero_ip(&ipzero);
 276
 277         remote_broadcast_subnet = make_subnet( "REMOTE_BROADCAST_SUBNET",
 278                                 REMOTE_BROADCAST_SUBNET,
 279                                 ipzero, ipzero, ipzero);
 280
 281         if((unicast_subnet == NULL) || (remote_broadcast_subnet == NULL))
 282                 return False;
 283
 284         /*
 285          * If we are WINS server, create the WINS_SERVER_SUBNET - don't put on
 286          * the linked list.
 287          */
 288
 289         if (lp_we_are_a_wins_server()) {
 290                 if( (wins_server_subnet = make_subnet( "WINS_SERVER_SUBNET",
 291                                                 WINS_SERVER_SUBNET,
 292                                                 ipzero, ipzero, ipzero )) == NULL )
 293                         return False;
 294         }
 295
 296         return True;
 297 }
 298
 299 /*******************************************************************
 300 Function to tell us if we can use the unicast subnet.
 301 ******************************************************************/
 302
 303 BOOL we_are_a_wins_client(void)
 304 {
 305         if (wins_srv_count() > 0) {
 306                 return True;
 307         }
 308
 309         return False;
 310 }
 311
 312 /*******************************************************************
 313 Access function used by NEXT_SUBNET_INCLUDING_UNICAST
 314 ******************************************************************/
 315
 316 struct subnet_record *get_next_subnet_maybe_unicast(struct subnet_record *subrec)
 317 {
 318         if(subrec == unicast_subnet)
 319                 return NULL;
 320         else if((subrec->next == NULL) && we_are_a_wins_client())
 321                 return unicast_subnet;
 322         else
 323                 return subrec->next;
 324 }
 325
 326 /*******************************************************************
 327  Access function used by retransmit_or_expire_response_records() in
 328  nmbd_packets.c. Patch from Andrey Alekseyev <fetch@muffin.arcadia.spb.ru>
 329  Needed when we need to enumerate all the broadcast, unicast and
 330  WINS subnets.
 331 ******************************************************************/
 332
 333 struct subnet_record *get_next_subnet_maybe_unicast_or_wins_server(struct subnet_record *subrec)
 334 {
 335         if(subrec == unicast_subnet) {
 336                 if(wins_server_subnet)
 337                         return wins_server_subnet;
 338                 else
 339                         return NULL;
 340         }
 341
 342         if(wins_server_subnet && subrec == wins_server_subnet)
 343                 return NULL;
 344
 345         if((subrec->next == NULL) && we_are_a_wins_client())
 346                 return unicast_subnet;
 347         else
 348                 return subrec->next;
 349 }