/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   NBT netbios routines and daemon - version 2
   Copyright (C) Andrew Tridgell 1994-1998
   Copyright (C) Luke Kenneth Casson Leighton 1994-1998
   Copyright (C) Jeremy Allison 1994-1998
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   
*/

#include "includes.h"
#include "smb.h"

extern int ClientNMB;

extern fstring global_myworkgroup;
extern char **my_netbios_names;

int updatecount = 0;

/*******************************************************************
  Remove all the servers in a work group.
  ******************************************************************/

void remove_all_servers(struct work_record *work)
{
  struct server_record *servrec;
  struct server_record *nexts;

  for (servrec = work->serverlist; servrec; servrec = nexts)
  {
    DEBUG(7,("remove_all_servers: Removing server %s\n",servrec->serv.name));
    nexts = servrec->next;

    if (servrec->prev)
      servrec->prev->next = servrec->next;
    if (servrec->next)
      servrec->next->prev = servrec->prev;

    if (work->serverlist == servrec)
      work->serverlist = servrec->next;

    ZERO_STRUCTP(servrec);
    SAFE_FREE(servrec);

  }

  work->subnet->work_changed = True;
}

/***************************************************************************
  Add a server into the a workgroup serverlist.
  **************************************************************************/

static void add_server_to_workgroup(struct work_record *work,
                             struct server_record *servrec)
{
  struct server_record *servrec2;

  if (!work->serverlist)
  {
    work->serverlist = servrec;
    servrec->prev = NULL;
    servrec->next = NULL;
    return;
  }

  for (servrec2 = work->serverlist; servrec2->next; servrec2 = servrec2->next)
    ;

  servrec2->next = servrec;
  servrec->next = NULL;
  servrec->prev = servrec2;
  work->subnet->work_changed = True;
}

/****************************************************************************
  Find a server in a server list.
  **************************************************************************/

struct server_record *find_server_in_workgroup(struct work_record *work, char *name)
{
  struct server_record *ret;
  
  for (ret = work->serverlist; ret; ret = ret->next)
  {
    if (strequal(ret->serv.name,name))
      return ret;
  }
  return NULL;
}


/****************************************************************************
  Remove a server entry from this workgroup.
  ****************************************************************************/

void remove_server_from_workgroup(struct work_record *work, struct server_record *servrec)
{
  if (servrec->prev)
    servrec->prev->next = servrec->next;
  if (servrec->next)
    servrec->next->prev = servrec->prev;

  if (work->serverlist == servrec) 
    work->serverlist = servrec->next; 

  ZERO_STRUCTP(servrec);
  SAFE_FREE(servrec);
  work->subnet->work_changed = True;
}

/****************************************************************************
  Create a server entry on this workgroup.
  ****************************************************************************/

struct server_record *create_server_on_workgroup(struct work_record *work,
                                                 char *name,int servertype, 
                                                 int ttl,char *comment)
{
  struct server_record *servrec;
  
  if (name[0] == '*')
  {
      DEBUG(7,("create_server_on_workgroup: not adding name starting with '*' (%s)\n",
             name));
      return (NULL);
  }
  
  if((servrec = find_server_in_workgroup(work, name)) != NULL)
  {
    DEBUG(0,("create_server_on_workgroup: Server %s already exists on \
workgroup %s. This is a bug.\n", name, work->work_group));
    return NULL;
  }
  
  if((servrec = (struct server_record *)malloc(sizeof(*servrec))) == NULL)
  {
    DEBUG(0,("create_server_entry_on_workgroup: malloc fail !\n"));
    return NULL;
  }

  memset((char *)servrec,'\0',sizeof(*servrec));
 
  servrec->subnet = work->subnet;
 
  StrnCpy(servrec->serv.name,name,sizeof(servrec->serv.name)-1);
  StrnCpy(servrec->serv.comment,comment,sizeof(servrec->serv.comment)-1);
  strupper(servrec->serv.name);
  servrec->serv.type  = servertype;

  update_server_ttl(servrec, ttl);
  
  add_server_to_workgroup(work, servrec);
      
  DEBUG(3,("create_server_on_workgroup: Created server entry %s of type %x (%s) on \
workgroup %s.\n", name,servertype,comment, work->work_group));
 
  work->subnet->work_changed = True;
 
  return(servrec);
}

/*******************************************************************
 Update the ttl field of a server record.
*******************************************************************/

void update_server_ttl(struct server_record *servrec, int ttl)
{
  if(ttl > lp_max_ttl())
    ttl = lp_max_ttl();

  if(is_myname(servrec->serv.name))
    servrec->death_time = PERMANENT_TTL;
  else
    servrec->death_time = (ttl != PERMANENT_TTL) ? time(NULL)+(ttl*3) : PERMANENT_TTL;

  servrec->subnet->work_changed = True;
}

/*******************************************************************
  Expire old servers in the serverlist. A time of -1 indicates 
  everybody dies except those with a death_time of PERMANENT_TTL (which is 0).
  This should only be called from expire_workgroups_and_servers().
  ******************************************************************/

void expire_servers(struct work_record *work, time_t t)
{
  struct server_record *servrec;
  struct server_record *nexts;
  
  for (servrec = work->serverlist; servrec; servrec = nexts)
  {
    nexts = servrec->next;

    if ((servrec->death_time != PERMANENT_TTL) && ((t == -1) || (servrec->death_time < t)))
    {
      DEBUG(3,("expire_old_servers: Removing timed out server %s\n",servrec->serv.name));
      remove_server_from_workgroup(work, servrec);
      work->subnet->work_changed = True;
    }
  }
}

/*******************************************************************
 Decide if we should write out a server record for this server.
 We return zero if we should not. Check if we've already written
 out this server record from an earlier subnet.
******************************************************************/

static uint32 write_this_server_name( struct subnet_record *subrec,
                                      struct work_record *work,
                                      struct server_record *servrec)
{
  struct subnet_record *ssub;
  struct work_record *iwork;

  /* Go through all the subnets we have already seen. */
  for (ssub = FIRST_SUBNET; ssub != subrec; ssub = NEXT_SUBNET_INCLUDING_UNICAST(ssub)) 
  {
    for(iwork = ssub->workgrouplist; iwork; iwork = iwork->next)
    {
      if(find_server_in_workgroup( iwork, servrec->serv.name) != NULL)
      {
        /*
         * We have already written out this server record, don't
         * do it again. This gives precedence to servers we have seen
         * on the broadcast subnets over servers that may have been
         * added via a sync on the unicast_subet.
         *
         * The correct way to do this is to have a serverlist file
         * per subnet - this means changes to smbd as well. I may
         * add this at a later date (JRA).
         */

        return 0;
      }
    }
  }

  return servrec->serv.type;
}

/*******************************************************************
 Decide if we should write out a workgroup record for this workgroup.
 We return zero if we should not. Don't write out global_myworkgroup (we've
 already done it) and also don't write out a second workgroup record
 on the unicast subnet that we've already written out on one of the
 broadcast subnets.
******************************************************************/

static uint32 write_this_workgroup_name( struct subnet_record *subrec, 
                                         struct work_record *work)
{
  struct subnet_record *ssub;

  if(strequal(global_myworkgroup, work->work_group))
    return 0;

  /* This is a workgroup we have seen on a broadcast subnet. All
     these have the same type. */

  if(subrec != unicast_subnet)
    return (SV_TYPE_DOMAIN_ENUM|SV_TYPE_NT|SV_TYPE_LOCAL_LIST_ONLY);

  for(ssub = FIRST_SUBNET; ssub;  ssub = NEXT_SUBNET_EXCLUDING_UNICAST(ssub))
  {
    /* This is the unicast subnet so check if we've already written out
       this subnet when we passed over the broadcast subnets. */

    if(find_workgroup_on_subnet( ssub, work->work_group) != NULL)
      return 0;
  }

  /* All workgroups on the unicast subnet (except our own, which we
     have already written out) cannot be local. */

  return (SV_TYPE_DOMAIN_ENUM|SV_TYPE_NT);
}

/*******************************************************************
  Write out the browse.dat file.
  ******************************************************************/

void write_browse_list_entry(FILE *fp, fstring name, uint32 rec_type,
		fstring local_master_browser_name, fstring description)
{
	fstring tmp;

	slprintf(tmp,sizeof(tmp)-1, "\"%s\"", name);
	fprintf(fp, "%-25s ", tmp);
	fprintf(fp, "%08x ", rec_type);
	slprintf(tmp, sizeof(tmp)-1, "\"%s\" ", local_master_browser_name);
	fprintf(fp, "%-30s", tmp);
	fprintf(fp, "\"%s\"\n", description);
}

void write_browse_list(time_t t, BOOL force_write)
{   
  struct subnet_record *subrec;
  struct work_record *work;
  struct server_record *servrec;
  pstring fname,fnamenew;
  uint32 stype;
  int i;
  FILE *fp;
  BOOL list_changed = force_write;
  static time_t lasttime = 0;
    
  /* Always dump if we're being told to by a signal. */
  if(force_write == False)
  {
    if (!lasttime)
      lasttime = t;
    if (t - lasttime < 5)
      return;
  }

  lasttime = t;

  dump_workgroups(force_write);
 
  for (subrec = FIRST_SUBNET; subrec ; subrec = NEXT_SUBNET_INCLUDING_UNICAST(subrec))
  {
    if(subrec->work_changed)
    {
      list_changed = True;
      break;
    }
  }

  if(!list_changed)
    return;

  updatecount++;
    
  pstrcpy(fname,lp_lockdir());
  trim_string( fname, strlen( fname )+1, NULL, 0, "/", sizeof( "/" ));
  pstrcat(fname,"/");
  pstrcat(fname,SERVER_LIST);
  pstrcpy(fnamenew,fname);
  pstrcat(fnamenew,".");
 
  fp = sys_fopen(fnamenew,"w");
 
  if (!fp)
  {
    DEBUG(0,("write_browse_list: Can't open file %s. Error was %s\n",
              fnamenew,strerror(errno)));
    return;
  } 
  
  /*
   * Write out a record for our workgroup. Use the record from the first
   * subnet.
   */

  if((work = find_workgroup_on_subnet(FIRST_SUBNET, global_myworkgroup)) == NULL)
  { 
    DEBUG(0,("write_browse_list: Fatal error - cannot find my workgroup %s\n",
             global_myworkgroup));
    fclose(fp);
    return;
  }

  write_browse_list_entry(fp, work->work_group, SV_TYPE_DOMAIN_ENUM|SV_TYPE_NT|SV_TYPE_LOCAL_LIST_ONLY, 
     work->local_master_browser_name, work->work_group);

  /* 
   * We need to do something special for our own names.
   * This is due to the fact that we may be a local master browser on
   * one of our broadcast subnets, and a domain master on the unicast
   * subnet. We iterate over the subnets and only write out the name
   * once.
   */

  for (i=0; my_netbios_names[i]; i++)
  {
    stype = 0;
    for (subrec = FIRST_SUBNET; subrec ; subrec = NEXT_SUBNET_INCLUDING_UNICAST(subrec))
    {
      if((work = find_workgroup_on_subnet( subrec, global_myworkgroup )) == NULL)
        continue;
      if((servrec = find_server_in_workgroup( work, my_netbios_names[i])) == NULL)
        continue;

      stype |= servrec->serv.type;
    }

    /* Output server details, plus what workgroup they're in. */
    write_browse_list_entry(fp, my_netbios_names[i], stype, 
       string_truncate(lp_serverstring(), MAX_SERVER_STRING_LENGTH), 
       global_myworkgroup);

  }
      
  for (subrec = FIRST_SUBNET; subrec ; subrec = NEXT_SUBNET_INCLUDING_UNICAST(subrec)) 
  { 
    subrec->work_changed = False;

    for (work = subrec->workgrouplist; work ; work = work->next)
    {
      /* Write out a workgroup record for a workgroup. */
      uint32 wg_type = write_this_workgroup_name( subrec, work);

      if(wg_type)
	write_browse_list_entry(fp, work->work_group, wg_type, 
				work->local_master_browser_name, 
				work->work_group);

      /* Now write out any server records a workgroup may have. */

      for (servrec = work->serverlist; servrec ; servrec = servrec->next)
      {
        uint32 serv_type;

        /* We have already written our names here. */
        if(is_myname(servrec->serv.name))
          continue; 

        serv_type = write_this_server_name(subrec, work, servrec);

	/* Output server details, plus what workgroup they're in. */
        if(serv_type)
	  write_browse_list_entry(fp, servrec->serv.name, serv_type, 
				  servrec->serv.comment, work->work_group);
      }
    }
  } 
  
  fclose(fp);
  unlink(fname);
  chmod(fnamenew,0644);
  rename(fnamenew,fname);
  DEBUG(3,("write_browse_list: Wrote browse list into file %s\n",fname));
}