source/namebrowse.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    NBT netbios routines and daemon - version 2
   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    Revision History:
  22
  23    14 jan 96: lkcl@pires.co.uk
  24    added multiple workgroup domain master support
  25
  26 */
  27
  28 #include "includes.h"
  29 #include "smb.h"
  30
  31 extern int ClientNMB;
  32
  33 extern int DEBUGLEVEL;
  34
  35 extern struct in_addr wins_ip;
  36
  37 /* this is our browse master/backup cache database */
  38 static struct browse_cache_record *browserlist = NULL;
  39
  40
  41 /***************************************************************************
  42   add a browser into the list
  43   **************************************************************************/
  44 static void add_browse_cache(struct browse_cache_record *b)
  45 {
  46   struct browse_cache_record *b2;
  47
  48   if (!browserlist)
  49     {
  50       browserlist = b;
  51       b->prev = NULL;
  52       b->next = NULL;
  53       return;
  54     }
  55
  56   for (b2 = browserlist; b2->next; b2 = b2->next) ;
  57
  58   b2->next = b;
  59   b->next = NULL;
  60   b->prev = b2;
  61 }
  62
  63
  64 /*******************************************************************
  65   remove old browse entries
  66   ******************************************************************/
  67 void expire_browse_cache(time_t t)
  68 {
  69   struct browse_cache_record *b;
  70   struct browse_cache_record *nextb;
  71
  72   /* expire old entries in the serverlist */
  73   for (b = browserlist; b; b = nextb)
  74     {
  75       if (b->synced && b->sync_time < t)
  76         {
  77           DEBUG(3,("Removing dead cached browser %s\n",b->name));
  78           nextb = b->next;
  79
  80           if (b->prev) b->prev->next = b->next;
  81           if (b->next) b->next->prev = b->prev;
  82
  83           if (browserlist == b) browserlist = b->next;
  84
  85           free(b);
  86         }
  87       else
  88         {
  89           nextb = b->next;
  90         }
  91     }
  92 }
  93
  94 /****************************************************************************
  95   add a browser entry
  96   ****************************************************************************/
  97 struct browse_cache_record *add_browser_entry(char *name, int type, char *wg,
  98                                               time_t ttl, struct subnet_record *d,
  99                                               struct in_addr ip, BOOL local)
 100 {
 101   BOOL newentry=False;
 102
 103   struct browse_cache_record *b;
 104
 105   /* search for the entry: if it's already in the cache, update that entry */
 106   for (b = browserlist; b; b = b->next)
 107     {
 108       if (ip_equal(ip,b->ip) && strequal(b->group, wg)) break;
 109     }
 110
 111   if (b && b->synced)
 112     {
 113       /* entries get left in the cache for a while. this stops sync'ing too
 114          often if the network is large */
 115       DEBUG(4, ("browser %s %s %s already sync'd at time %d\n",
 116                 b->name, b->group, inet_ntoa(b->ip), b->sync_time));
 117       return NULL;
 118     }
 119
 120   if (!b)
 121     {
 122       newentry = True;
 123       b = (struct browse_cache_record *)malloc(sizeof(*b));
 124
 125       if (!b) return(NULL);
 126
 127       bzero((char *)b,sizeof(*b));
 128     }
 129
 130   /* update the entry */
 131   ttl = time(NULL)+ttl;
 132
 133   StrnCpy(b->name ,name,sizeof(b->name )-1);
 134   StrnCpy(b->group,wg  ,sizeof(b->group)-1);
 135   strupper(b->name);
 136   strupper(b->group);
 137
 138   b->ip     = ip;
 139   b->type   = type;
 140   b->local  = local; /* local server list sync or complete sync required */
 141   b->subnet = d;
 142
 143   if (newentry || ttl < b->sync_time)
 144     b->sync_time = ttl;
 145
 146   if (newentry)
 147     {
 148       b->synced = False;
 149       add_browse_cache(b);
 150
 151       DEBUG(3,("Added cache entry %s %s(%2x) %s ttl %d\n",
 152                wg, name, type, inet_ntoa(ip),ttl));
 153     }
 154   else
 155     {
 156       DEBUG(3,("Updated cache entry %s %s(%2x) %s ttl %d\n",
 157                wg, name, type, inet_ntoa(ip),ttl));
 158     }
 159
 160   return(b);
 161 }
 162
 163
 164 /****************************************************************************
 165 find a server responsible for a workgroup, and sync browse lists
 166 **************************************************************************/
 167 static void start_sync_browse_entry(struct browse_cache_record *b)
 168 {
 169   struct subnet_record *d = b->subnet;
 170   struct work_record *work;
 171
 172   /* Check panic conditions - these should not be true. */
 173   if(b->subnet != wins_subnet) {
 174       DEBUG(0,
 175         ("start_sync_browse_entry: ERROR sync requested on non-WINS subnet.\n"));
 176       return;
 177   }
 178
 179   if (!(work = find_workgroupstruct(d, b->group, False))) {
 180       DEBUG(0, ("start_sync_browse_entry: failed to get a \
 181 workgroup for a browse cache entry workgroup %s, server %s\n",
 182                 b->group, b->name));
 183       return;
 184   }
 185
 186   DEBUG(4, ("start_sync_browse_entry: Initiating %s sync with %s<0x20>, \
 187 workgroup %s\n",
 188              b->local ? "local" : "remote", b->name, b->group));
 189
 190   /* first check whether the server we intend to sync with exists. if it
 191      doesn't, the server must have died. o dear. */
 192
 193   /* see response_netbios_packet() or expire_netbios_response_entries() */
 194   /* We cheat here by using the my_comment field of the response_record
 195      struct as the workgroup name we are going to do the sync for.
 196      This is because the reply packet doesn't include the workgroup, but
 197      we need it when the reply comes back.
 198   */
 199   queue_netbios_packet(d,ClientNMB,NMB_QUERY,
 200          b->local?NAME_QUERY_SYNC_LOCAL:NAME_QUERY_SYNC_REMOTE,
 201          b->name,0x20,0,0,0,NULL,b->group,
 202          False,False,b->ip,b->ip);
 203
 204   b->synced = True;
 205 }
 206
 207
 208 /****************************************************************************
 209   search through browser list for an entry to sync with
 210   **************************************************************************/
 211 void do_browser_lists(time_t t)
 212 {
 213   struct browse_cache_record *b;
 214   static time_t last = 0;
 215
 216   if (t-last < 20)
 217    {
 218      DEBUG(9,("do_browser_lists: returning due to t(%d) - last(%d) < 20\n",
 219              t, last));
 220      return; /* don't do too many of these at once! */
 221                            /* XXXX equally this period should not be too long
 222                               the server may die in the intervening gap */
 223    }
 224   last = t;
 225
 226   /* pick any entry in the list, preferably one whose time is up */
 227   for (b = browserlist; b && b->next; b = b->next)
 228     {
 229       if (b->sync_time < t && b->synced == False) break;
 230     }
 231
 232   if (b && !b->synced)
 233   {
 234     /* sync with the selected entry then remove some dead entries */
 235     DEBUG(4,("do_browser_lists: Initiating sync with %s, workgroup %s\n",
 236               b->name, b->group));
 237     start_sync_browse_entry(b);
 238   }
 239   else
 240   {
 241     DEBUG(9, ("do_browser_lists: no entries to sync.\n"));
 242   }
 243
 244   expire_browse_cache(t - 60);
 245 }
 246