source4/nbt_server/winsserver.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    core wins server handling
   5
   6    Copyright (C) Andrew Tridgell        2005
   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 2 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
  23 #include "includes.h"
  24 #include "nbt_server/nbt_server.h"
  25 #include "nbt_server/winsdb.h"
  26 #include "system/time.h"
  27
  28 /*
  29   work out the ttl we will use given a client requested ttl
  30 */
  31 uint32_t wins_server_ttl(struct wins_server *winssrv, uint32_t ttl)
  32 {
  33         ttl = MIN(ttl, winssrv->max_ttl);
  34         ttl = MAX(ttl, winssrv->min_ttl);
  35         return ttl;
  36 }
  37
  38 /*
  39   register a new name with WINS
  40 */
  41 static uint8_t wins_register_new(struct nbt_name_socket *nbtsock,
  42                                  struct nbt_name_packet *packet,
  43                                  const char *src_address, int src_port)
  44 {
  45         struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private,
  46                                                        struct nbtd_interface);
  47         struct wins_server *winssrv = iface->nbtsrv->winssrv;
  48         struct nbt_name *name = &packet->questions[0].name;
  49         uint32_t ttl = wins_server_ttl(winssrv, packet->additional[0].ttl);
  50         uint16_t nb_flags = packet->additional[0].rdata.netbios.addresses[0].nb_flags;
  51         const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
  52         struct winsdb_record rec;
  53
  54         rec.name          = name;
  55         rec.nb_flags      = nb_flags;
  56         rec.state         = WINS_REC_ACTIVE;
  57         rec.expire_time   = time(NULL) + ttl;
  58         rec.registered_by = src_address;
  59         if (IS_GROUP_NAME(name, nb_flags)) {
  60                 rec.addresses     = str_list_make(packet, "255.255.255.255", NULL);
  61         } else {
  62                 rec.addresses     = str_list_make(packet, address, NULL);
  63         }
  64         if (rec.addresses == NULL) return NBT_RCODE_SVR;
  65
  66         DEBUG(4,("WINS: accepted registration of %s with address %s\n",
  67                  nbt_name_string(packet, name), rec.addresses[0]));
  68
  69         return winsdb_add(winssrv, &rec);
  70 }
  71
  72
  73 /*
  74   update the ttl on an existing record
  75 */
  76 static uint8_t wins_update_ttl(struct nbt_name_socket *nbtsock,
  77                                struct nbt_name_packet *packet,
  78                                struct winsdb_record *rec,
  79                                const char *src_address, int src_port)
  80 {
  81         struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private,
  82                                                        struct nbtd_interface);
  83         struct wins_server *winssrv = iface->nbtsrv->winssrv;
  84         uint32_t ttl = wins_server_ttl(winssrv, packet->additional[0].ttl);
  85         const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
  86         time_t now = time(NULL);
  87
  88         if (now + ttl > rec->expire_time) {
  89                 rec->expire_time   = now + ttl;
  90         }
  91         rec->registered_by = src_address;
  92
  93         DEBUG(5,("WINS: refreshed registration of %s at %s\n",
  94                  nbt_name_string(packet, rec->name), address));
  95
  96         return winsdb_modify(winssrv, rec);
  97 }
  98
  99 /*
 100   register a name
 101 */
 102 static void nbtd_winsserver_register(struct nbt_name_socket *nbtsock,
 103                                      struct nbt_name_packet *packet,
 104                                      const char *src_address, int src_port)
 105 {
 106         struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private,
 107                                                        struct nbtd_interface);
 108         struct wins_server *winssrv = iface->nbtsrv->winssrv;
 109         struct nbt_name *name = &packet->questions[0].name;
 110         struct winsdb_record *rec;
 111         uint8_t rcode = NBT_RCODE_OK;
 112         uint16_t nb_flags = packet->additional[0].rdata.netbios.addresses[0].nb_flags;
 113         const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
 114
 115         /* as a special case, the local master browser name is always accepted
 116            for registration, but never stored */
 117         if (name->type == NBT_NAME_MASTER) {
 118                 goto done;
 119         }
 120
 121         rec = winsdb_load(winssrv, name, packet);
 122         if (rec == NULL) {
 123                 rcode = wins_register_new(nbtsock, packet, src_address, src_port);
 124                 goto done;
 125         } else if (rec->state != WINS_REC_ACTIVE) {
 126                 winsdb_delete(winssrv, rec->name);
 127                 rcode = wins_register_new(nbtsock, packet, src_address, src_port);
 128                 goto done;
 129         }
 130
 131         /* its an active name - first see if the registration is of the right type */
 132         if ((rec->nb_flags & NBT_NM_GROUP) && !(nb_flags & NBT_NM_GROUP)) {
 133                 DEBUG(2,("WINS: Attempt to register unique name %s when group name is active\n",
 134                          nbt_name_string(packet, name)));
 135                 rcode = NBT_RCODE_ACT;
 136                 goto done;
 137         }
 138
 139         /* if its an active unique name, and the registration is for a group, then
 140            see if the unique name owner still wants the name */
 141         if (!(rec->nb_flags & NBT_NM_GROUP) && (nb_flags & NBT_NM_GROUP)) {
 142                 wins_register_wack(nbtsock, packet, rec, src_address, src_port);
 143                 return;
 144         }
 145
 146         /* if the registration is for a group, then just update the expiry time
 147            and we are done */
 148         if (IS_GROUP_NAME(name, nb_flags)) {
 149                 wins_update_ttl(nbtsock, packet, rec, src_address, src_port);
 150                 goto done;
 151         }
 152
 153         /* if the registration is for an address that is currently active, then
 154            just update the expiry time */
 155         if (str_list_check(rec->addresses, address)) {
 156                 wins_update_ttl(nbtsock, packet, rec, src_address, src_port);
 157                 goto done;
 158         }
 159
 160         /* we have to do a WACK to see if the current owner is willing
 161            to give up its claim */
 162         wins_register_wack(nbtsock, packet, rec, src_address, src_port);
 163         return;
 164
 165 done:
 166         nbtd_name_registration_reply(nbtsock, packet, src_address, src_port, rcode);
 167 }
 168
 169
 170
 171 /*
 172   query a name
 173 */
 174 static void nbtd_winsserver_query(struct nbt_name_socket *nbtsock,
 175                                   struct nbt_name_packet *packet,
 176                                   const char *src_address, int src_port)
 177 {
 178         struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private,
 179                                                        struct nbtd_interface);
 180         struct wins_server *winssrv = iface->nbtsrv->winssrv;
 181         struct nbt_name *name = &packet->questions[0].name;
 182         struct winsdb_record *rec;
 183
 184         rec = winsdb_load(winssrv, name, packet);
 185         if (rec == NULL || rec->state != WINS_REC_ACTIVE) {
 186                 nbtd_negative_name_query_reply(nbtsock, packet, src_address, src_port);
 187                 return;
 188         }
 189
 190         nbtd_name_query_reply(nbtsock, packet, src_address, src_port, name,
 191                               0, rec->nb_flags, rec->addresses);
 192 }
 193
 194 /*
 195   release a name
 196 */
 197 static void nbtd_winsserver_release(struct nbt_name_socket *nbtsock,
 198                                     struct nbt_name_packet *packet,
 199                                     const char *src_address, int src_port)
 200 {
 201         struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private,
 202                                                        struct nbtd_interface);
 203         struct wins_server *winssrv = iface->nbtsrv->winssrv;
 204         struct nbt_name *name = &packet->questions[0].name;
 205         struct winsdb_record *rec;
 206
 207         rec = winsdb_load(winssrv, name, packet);
 208         if (rec == NULL ||
 209             rec->state != WINS_REC_ACTIVE ||
 210             IS_GROUP_NAME(name, rec->nb_flags)) {
 211                 goto done;
 212         }
 213
 214         /* we only allow releases from an owner - other releases are
 215            silently ignored */
 216         if (str_list_check(rec->addresses, src_address)) {
 217                 const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
 218
 219                 DEBUG(4,("WINS: released name %s at %s\n", nbt_name_string(rec, rec->name), address));
 220                 str_list_remove(rec->addresses, address);
 221                 if (rec->addresses[0] == NULL) {
 222                         rec->state = WINS_REC_RELEASED;
 223                 }
 224                 winsdb_modify(winssrv, rec);
 225         }
 226
 227 done:
 228         /* we match w2k3 by always giving a positive reply to name releases. */
 229         nbtd_name_release_reply(nbtsock, packet, src_address, src_port, NBT_RCODE_OK);
 230 }
 231
 232
 233 /*
 234   answer a name query
 235 */
 236 void nbtd_winsserver_request(struct nbt_name_socket *nbtsock,
 237                              struct nbt_name_packet *packet,
 238                              const char *src_address, int src_port)
 239 {
 240         struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private,
 241                                                        struct nbtd_interface);
 242         struct wins_server *winssrv = iface->nbtsrv->winssrv;
 243         if ((packet->operation & NBT_FLAG_BROADCAST) || winssrv == NULL) {
 244                 return;
 245         }
 246
 247         switch (packet->operation & NBT_OPCODE) {
 248         case NBT_OPCODE_QUERY:
 249                 nbtd_winsserver_query(nbtsock, packet, src_address, src_port);
 250                 break;
 251
 252         case NBT_OPCODE_REGISTER:
 253         case NBT_OPCODE_REFRESH:
 254         case NBT_OPCODE_REFRESH2:
 255         case NBT_OPCODE_MULTI_HOME_REG:
 256                 nbtd_winsserver_register(nbtsock, packet, src_address, src_port);
 257                 break;
 258
 259         case NBT_OPCODE_RELEASE:
 260                 nbtd_winsserver_release(nbtsock, packet, src_address, src_port);
 261                 break;
 262         }
 263
 264 }
 265
 266 /*
 267   startup the WINS server, if configured
 268 */
 269 NTSTATUS nbtd_winsserver_init(struct nbtd_server *nbtsrv)
 270 {
 271         if (!lp_wins_support()) {
 272                 nbtsrv->winssrv = NULL;
 273                 return NT_STATUS_OK;
 274         }
 275
 276         nbtsrv->winssrv = talloc(nbtsrv, struct wins_server);
 277         NT_STATUS_HAVE_NO_MEMORY(nbtsrv->winssrv);
 278
 279         nbtsrv->winssrv->max_ttl = lp_max_wins_ttl();
 280         nbtsrv->winssrv->min_ttl = lp_min_wins_ttl();
 281
 282         return winsdb_init(nbtsrv->winssrv);
 283 }