source/nameresp.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    NBT netbios library routines
   5    Copyright (C) Andrew Tridgell 1994-1996
   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 ipgrp;
  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   switch (n->state)
  49   {
  50     case NAME_QUERY_CONFIRM:
  51     {
  52                 if (!lp_wins_support()) return; /* only if we're a WINS server */
  53
  54                 if (n->num_msgs == 0)
  55         {
  56                         /* oops. name query had no response. check that the name is
  57                            unique and then remove it from our WINS database */
  58
  59                         /* IMPORTANT: see query_refresh_names() */
  60
  61                         if ((!NAME_GROUP(n->nb_flags)))
  62                         {
  63                                 struct subnet_record *d1 = find_subnet(ipgrp);
  64                                 if (d1)
  65                                 {
  66                                         /* remove the name that had been registered with us,
  67                                            and we're now getting no response when challenging.
  68                                            see rfc1001.txt 15.5.2
  69                                          */
  70                                         remove_netbios_name(d1, n->name.name, n->name.name_type,
  71                                                                         REGISTER, n->send_ip);
  72                                 }
  73                         }
  74                 }
  75                 break;
  76     }
  77
  78         case NAME_QUERY_MST_CHK:
  79         {
  80           /* if no response received, the master browser must have gone
  81                  down on that subnet, without telling anyone. */
  82
  83           /* IMPORTANT: see response_netbios_packet() */
  84
  85           if (n->num_msgs == 0)
  86                   browser_gone(n->name.name, n->send_ip);
  87           break;
  88         }
  89
  90         case NAME_RELEASE:
  91         {
  92           /* if no response received, it must be OK for us to release the
  93                  name. nobody objected (including a potentially dead or deaf
  94                  WINS server) */
  95
  96           /* IMPORTANT: see response_name_release() */
  97
  98           if (ismyip(n->send_ip))
  99           {
 100                 name_unregister_work(d,n->name.name,n->name.name_type);
 101           }
 102           if (!n->bcast)
 103           {
 104                  DEBUG(0,("WINS server did not respond to name release!\n"));
 105          /* XXXX whoops. we have problems. must deal with this */
 106           }
 107           break;
 108         }
 109
 110         case NAME_REGISTER_CHALLENGE:
 111         {
 112                 /* name challenge: no reply. we can reply to the person that
 113                    wanted the unique name and tell them that they can have it
 114                  */
 115
 116                 add_netbios_entry(d, n->name.name, n->name.name_type,
 117                                                         n->nb_flags, GET_TTL(0), REGISTER,
 118                                                         n->reply_to_ip, False, True);
 119
 120                 send_name_response(n->fd, n->response_id, NMB_REG,
 121                                                 True, True,
 122                                                 &n->name, n->nb_flags, GET_TTL(0), n->reply_to_ip);
 123                 break;
 124         }
 125         case NAME_REGISTER:
 126         {
 127           /* if no response received, and we are using a broadcast registration
 128                  method, it must be OK for us to register the name: nobody objected
 129                  on that subnet. if we are using a WINS server, then the WINS
 130                  server must be dead or deaf.
 131            */
 132           if (n->bcast)
 133           {
 134                 /* broadcast method: implicit acceptance of the name registration
 135                    by not receiving any objections. */
 136
 137                 /* IMPORTANT: see response_name_reg() */
 138
 139                 name_register_work(d,n->name.name,n->name.name_type,
 140                                 n->nb_flags, n->ttl, n->send_ip, n->bcast);
 141           }
 142           else
 143           {
 144                 /* XXXX oops. this is where i wish this code could retry DGRAM
 145                    packets. we directed a name registration at a WINS server, and
 146                    received no response. rfc1001.txt states that after retrying,
 147                    we should assume the WINS server is dead, and fall back to
 148                    broadcasting. */
 149
 150                  DEBUG(1,("WINS server did not respond to name registration!\n"));
 151          /* XXXX whoops. we have problems. must deal with this */
 152           }
 153           break;
 154         }
 155
 156         default:
 157         {
 158           /* nothing to do but delete the dead expected-response structure */
 159           /* this is normal. */
 160           break;
 161         }
 162   }
 163 }
 164
 165
 166 /*******************************************************************
 167   remove old name response entries
 168
 169   XXXX retry code needs to be added, including a retry wait period and a count
 170        see name_query() and name_status() for suggested implementation.
 171
 172   ******************************************************************/
 173 void expire_netbios_response_entries()
 174 {
 175   struct subnet_record *d;
 176
 177   for (d = subnetlist; d; d = d->next)
 178   {
 179     struct response_record *n, *nextn;
 180
 181     for (n = d->responselist; n; n = nextn)
 182     {
 183           nextn = n->next;
 184
 185       if (n->repeat_time <= time(NULL))
 186           {
 187                   if (n->repeat_count > 0)
 188                   {
 189                         /* resend the entry */
 190                         initiate_netbios_packet(&n->response_id, n->fd, n->quest_type,
 191                                                 n->name.name, n->name.name_type,
 192                                       n->nb_flags, n->bcast, n->recurse, n->send_ip);
 193
 194             n->repeat_time += n->repeat_interval; /* XXXX ms needed */
 195             n->repeat_count--;
 196
 197                   }
 198                   else
 199                   {
 200               DEBUG(4,("timeout response %d for %s %s\n",
 201                                                 n->response_id, namestr(&n->name),
 202                         inet_ntoa(n->send_ip)));
 203
 204                           dead_netbios_entry    (d,n); /* process the non-response */
 205               remove_response_record(d,n); /* remove the non-response */
 206
 207                           continue;
 208                    }
 209           }
 210     }
 211   }
 212 }
 213
 214
 215 /****************************************************************************
 216   wrapper function to override a broadcast message and send it to the WINS
 217   name server instead, if it exists. if wins is false, and there has been no
 218   WINS server specified, the packet will NOT be sent.
 219   ****************************************************************************/
 220 struct response_record *queue_netbios_pkt_wins(struct subnet_record *d,
 221                                 int fd,int quest_type,enum state_type state,
 222                             char *name,int name_type,int nb_flags, time_t ttl,
 223                             BOOL bcast,BOOL recurse,
 224                                 struct in_addr send_ip, struct in_addr reply_to_ip)
 225 {
 226   /* XXXX note: please see rfc1001.txt section 10 for details on this
 227      function: it is currently inappropriate to use this - it will do
 228      for now - once there is a clarification of B, M and P nodes and
 229      which one samba is supposed to be
 230    */
 231
 232   if ((!lp_wins_support()) && (*lp_wins_server()))
 233     {
 234       /* samba is not a WINS server, and we are using a WINS server */
 235       struct in_addr wins_ip;
 236       wins_ip = *interpret_addr2(lp_wins_server());
 237
 238       if (!zero_ip(wins_ip))
 239         {
 240           bcast = False;
 241           send_ip = wins_ip;
 242         }
 243       else
 244         {
 245           /* oops. smb.conf's wins server parameter MUST be a host_name
 246              or an ip_address. */
 247           DEBUG(0,("invalid smb.conf parameter 'wins server'\n"));
 248         }
 249     }
 250
 251   if (zero_ip(send_ip)) return NULL;
 252
 253   return queue_netbios_packet(d,fd, quest_type, state,
 254                        name, name_type, nb_flags, ttl,
 255                        bcast, recurse, send_ip, reply_to_ip);
 256 }
 257
 258
 259 /****************************************************************************
 260   initiate a netbios name query to find someone's or someones' IP
 261   this is intended to be used (not exclusively) for broadcasting to
 262   master browsers (WORKGROUP(1d or 1b) or __MSBROWSE__(1)) to get
 263   complete lists across a wide area network
 264   ****************************************************************************/
 265 struct response_record *queue_netbios_packet(struct subnet_record *d,
 266                         int fd,int quest_type,enum state_type state,char *name,
 267                         int name_type,int nb_flags, time_t ttl,
 268                             BOOL bcast,BOOL recurse,
 269                                 struct in_addr send_ip, struct in_addr reply_to_ip)
 270 {
 271   struct in_addr wins_ip = ipgrp;
 272   struct response_record *n;
 273   uint16 id = 0xffff;
 274
 275   /* ha ha. no. do NOT broadcast to 255.255.255.255: it's a pseudo address */
 276   if (ip_equal(wins_ip, send_ip)) return NULL;
 277
 278   initiate_netbios_packet(&id, fd, quest_type, name, name_type,
 279                                       nb_flags, bcast, recurse, send_ip);
 280
 281   if (id == 0xffff) {
 282     DEBUG(4,("did not initiate netbios packet: %s\n", inet_ntoa(send_ip)));
 283     return NULL;
 284   }
 285
 286   if ((n = make_response_queue_record(state,id,fd,
 287                                                 quest_type,name,name_type,nb_flags,ttl,
 288                                                 bcast,recurse,send_ip,reply_to_ip)))
 289     {
 290       add_response_record(d,n);
 291       return n;
 292     }
 293    return NULL;
 294 }