source/nameresp.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    NBT netbios library routines
   5    Copyright (C) Andrew Tridgell 1994-1997
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21    Module name: nameresp.c
  22
  23 */
  24
  25 #include "includes.h"
  26
  27 extern int ClientNMB;
  28 extern int ClientDGRAM;
  29
  30 extern struct subnet_record *subnetlist;
  31
  32 extern int DEBUGLEVEL;
  33
  34 extern pstring scope;
  35 extern struct in_addr ipzero;
  36 extern struct in_addr wins_ip;
  37
  38
  39 /***************************************************************************
  40   deals with an entry before it dies
  41   **************************************************************************/
  42 static void dead_netbios_entry(struct subnet_record *d,
  43                                 struct response_record *n)
  44 {
  45   DEBUG(3,("Removing dead netbios entry for %s %s (num_msgs=%d)\n",
  46            inet_ntoa(n->send_ip), namestr(&n->name), n->num_msgs));
  47
  48   debug_state_type(n->state);
  49
  50   switch (n->state)
  51   {
  52     case NAME_QUERY_CONFIRM:
  53     {
  54       if (!lp_wins_support()) return; /* only if we're a WINS server */
  55
  56       if (n->num_msgs == 0)
  57         {
  58           /* oops. name query had no response. check that the name is
  59              unique and then remove it from our WINS database */
  60
  61           /* IMPORTANT: see query_refresh_names() */
  62
  63           if ((!NAME_GROUP(n->nb_flags)))
  64             {
  65               struct subnet_record *d1 = wins_subnet;
  66               if (d1)
  67                 {
  68                   /* remove the name that had been registered with us,
  69                      and we're now getting no response when challenging.
  70                      see rfc1001.txt 15.5.2
  71                      */
  72                   remove_netbios_name(d1, n->name.name, n->name.name_type,
  73                                       REGISTER, n->send_ip);
  74                 }
  75             }
  76         }
  77       break;
  78     }
  79
  80   case NAME_QUERY_MST_CHK:
  81     {
  82       /* if no response received, the master browser must have gone
  83          down on that subnet, without telling anyone. */
  84
  85       /* IMPORTANT: see response_netbios_packet() */
  86
  87       if (n->num_msgs == 0)
  88         browser_gone(n->name.name, n->send_ip);
  89       break;
  90     }
  91
  92   case NAME_RELEASE:
  93     {
  94       /* if no response received, it must be OK for us to release the
  95          name. nobody objected (including a potentially dead or deaf
  96          WINS server) */
  97
  98       /* IMPORTANT: see response_name_release() */
  99
 100       if (ismyip(n->send_ip))
 101         {
 102           name_unregister_work(d,n->name.name,n->name.name_type);
 103         }
 104       if (!n->bcast && n->num_msgs == 0)
 105         {
 106           DEBUG(0,("WINS server did not respond to name release!\n"));
 107           /* XXXX whoops. we have problems. must deal with this */
 108         }
 109       break;
 110     }
 111
 112   case NAME_REGISTER_CHALLENGE:
 113     {
 114       /* name challenge: no reply. we can reply to the person that
 115          wanted the unique name and tell them that they can have it
 116          */
 117
 118       add_name_respond(d,n->fd,d->myip, n->response_id ,&n->name,
 119                        n->nb_flags, GET_TTL(0),
 120                        n->reply_to_ip, False, n->reply_to_ip);
 121
 122       if (!n->bcast && n->num_msgs == 0)
 123         {
 124           DEBUG(1,("WINS server did not respond to name registration!\n"));
 125           /* XXXX whoops. we have problems. must deal with this */
 126         }
 127       break;
 128     }
 129
 130   case NAME_REGISTER:
 131     {
 132       /* if no response received, and we are using a broadcast registration
 133          method, it must be OK for us to register the name: nobody objected
 134          on that subnet. if we are using a WINS server, then the WINS
 135          server must be dead or deaf.
 136          */
 137       if (n->num_msgs == 0)
 138         {
 139           if (n->bcast)
 140             {
 141               /* broadcast method: implicit acceptance of the name registration
 142                  by not receiving any objections. */
 143
 144               /* IMPORTANT: see response_name_reg() */
 145
 146               name_register_work(d,n->name.name,n->name.name_type,
 147                                  n->nb_flags, n->ttl, n->reply_to_ip, n->bcast);
 148             }
 149           else
 150             {
 151               /* received no response. rfc1001.txt states that after retrying,
 152                  we should assume the WINS server is dead, and fall back to
 153                  broadcasting (see bits about M nodes: can't find any right
 154                  now) */
 155
 156               DEBUG(1,("WINS server did not respond to name registration!\n"));
 157               /* XXXX whoops. we have problems. must deal with this */
 158             }
 159         }
 160       break;
 161     }
 162
 163   case NAME_QUERY_DOMAIN:
 164     {
 165       /* if no response was received, there is no domain controller for
 166          this DOMAIN registered within WINS.  it's ok for us to register
 167          the DOMAIN<1b> name.
 168          */
 169
 170       if (n->num_msgs == 0)
 171         {
 172           struct work_record *work = find_workgroupstruct(d,n->name.name,False);
 173           if (work && d)
 174             {
 175               become_domain_master(d,work);
 176             }
 177         }
 178       else
 179         {
 180           DEBUG(1, ("nmbd configured as domain master and one already exists\n"));
 181         }
 182       break;
 183     }
 184
 185   default:
 186     {
 187       /* nothing to do but delete the dead expected-response structure */
 188       /* this is normal. */
 189       break;
 190     }
 191   }
 192 }
 193
 194
 195 /*******************************************************************
 196   remove old name response entries
 197
 198   XXXX retry code needs to be added, including a retry wait period and a count
 199        see name_query() and name_status() for suggested implementation.
 200
 201   ******************************************************************/
 202 void expire_netbios_response_entries(time_t t)
 203 {
 204   struct subnet_record *d;
 205
 206   for (d = FIRST_SUBNET; d; d = NEXT_SUBNET_INCLUDING_WINS(d))
 207   {
 208     struct response_record *n, *nextn;
 209
 210     for (n = d->responselist; n; n = nextn)
 211     {
 212       nextn = n->next;
 213
 214       if (n->repeat_time <= t)
 215       {
 216         if (n->repeat_count > 0)
 217         {
 218           /* resend the entry */
 219           initiate_netbios_packet(&n->response_id, n->fd, n->quest_type,
 220                          n->name.name, n->name.name_type,
 221                          n->nb_flags, n->bcast, n->recurse, n->send_ip);
 222
 223           n->repeat_time += n->repeat_interval; /* XXXX ms needed */
 224           n->repeat_count--;
 225
 226         }
 227         else
 228         {
 229           DEBUG(4,("timeout response %d for %s %s\n",
 230                    n->response_id, namestr(&n->name),
 231                    inet_ntoa(n->send_ip)));
 232
 233           dead_netbios_entry(d,n); /* process the non-response */
 234           remove_response_record(d,n); /* remove the non-response */
 235
 236           continue;
 237         }
 238       }
 239     }
 240   }
 241 }
 242
 243
 244 /****************************************************************************
 245   wrapper function to override a broadcast message and send it to the WINS
 246   name server instead, if it exists. if wins is false, and there has been no
 247   WINS server specified, the packet will NOT be sent.
 248   ****************************************************************************/
 249 struct response_record *queue_netbios_pkt_wins(
 250                                 int fd,int quest_type,enum state_type state,
 251                             char *name,int name_type,int nb_flags, time_t ttl,
 252                                 int server_type, char *my_name, char *my_comment,
 253                             BOOL bcast,BOOL recurse,
 254                                 struct in_addr send_ip, struct in_addr reply_to_ip)
 255 {
 256   /* XXXX note: please see rfc1001.txt section 10 for details on this
 257      function: it is currently inappropriate to use this - it will do
 258      for now - once there is a clarification of B, M and P nodes and
 259      which one samba is supposed to be
 260    */
 261
 262   if ((!lp_wins_support()) && (*lp_wins_server()))
 263     {
 264       /* samba is not a WINS server, and we are using a WINS server */
 265       struct in_addr real_wins_ip;
 266       real_wins_ip = *interpret_addr2(lp_wins_server());
 267
 268       if (!zero_ip(real_wins_ip))
 269         {
 270           bcast = False;
 271           send_ip = real_wins_ip;
 272         }
 273       else
 274         {
 275           /* oops. smb.conf's wins server parameter MUST be a host_name
 276              or an ip_address. */
 277           DEBUG(0,("invalid smb.conf parameter 'wins server'\n"));
 278         }
 279     }
 280
 281   if (zero_ip(send_ip)) return NULL;
 282
 283   return queue_netbios_packet(wins_subnet,fd, quest_type, state,
 284                        name, name_type, nb_flags, ttl,
 285                server_type,my_name,my_comment,
 286                        bcast, recurse, send_ip, reply_to_ip);
 287 }
 288
 289
 290 /****************************************************************************
 291   initiate a netbios name query to find someone's or someones' IP
 292   this is intended to be used (not exclusively) for broadcasting to
 293   master browsers (WORKGROUP(1d or 1b) or __MSBROWSE__(1)) to get
 294   complete lists across a wide area network
 295   ****************************************************************************/
 296 struct response_record *queue_netbios_packet(struct subnet_record *d,
 297                         int fd,int quest_type,enum state_type state,char *name,
 298                         int name_type,int nb_flags, time_t ttl,
 299                         int server_type, char *my_name, char *my_comment,
 300                         BOOL bcast,BOOL recurse,
 301                         struct in_addr send_ip, struct in_addr reply_to_ip)
 302 {
 303   struct response_record *n;
 304   uint16 id = 0xffff;
 305
 306   /* ha ha. no. do NOT broadcast to 255.255.255.255: it's a pseudo address */
 307   if (ip_equal(wins_ip, send_ip)) return NULL;
 308
 309   initiate_netbios_packet(&id, fd, quest_type, name, name_type,
 310                           nb_flags, bcast, recurse, send_ip);
 311
 312   if (id == 0xffff) {
 313     DEBUG(4,("did not initiate netbios packet: %s\n", inet_ntoa(send_ip)));
 314     return NULL;
 315   }
 316
 317   if ((n = make_response_queue_record(state,id,fd,
 318                                       quest_type,name,name_type,nb_flags,ttl,
 319                                       server_type,my_name, my_comment,
 320                                       bcast,recurse,send_ip,reply_to_ip)))
 321     {
 322       add_response_record(d,n);
 323       return n;
 324     }
 325    return NULL;
 326 }