samba-mirror/source3/nmbd/nmbd_browserdb.c

/* 
   Unix SMB/CIFS implementation.
   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
   Copyright (C) Christopher R. Hertel 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 3 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, see <http://www.gnu.org/licenses/>.
   
*/
/* -------------------------------------------------------------------------- **
 * Modified July 1998 by CRH.
 *  I converted this module to use the canned doubly-linked lists.  I also
 *  added comments above the functions where possible.
 */

#include "includes.h"
#include "nmbd/nmbd.h"
#include "lib/util/string_wrappers.h"

/* -------------------------------------------------------------------------- **
 * Variables...
 *
 *  lmb_browserlist - This is our local master browser list. 
 */

struct browse_cache_record *lmb_browserlist;

/* -------------------------------------------------------------------------- **
 * Functions...
 */

/* ************************************************************************** **
 * Remove and free a browser list entry.
 *
 *  Input:  browc - A pointer to the entry to be removed from the list and
 *                  freed.
 *  Output: none.
 *
 * ************************************************************************** **
 */
static void remove_lmb_browser_entry( struct browse_cache_record *browc )
{
	DLIST_REMOVE(lmb_browserlist, browc);
	SAFE_FREE(browc);
}

/* ************************************************************************** **
 * Update a browser death time.
 *
 *  Input:  browc - Pointer to the entry to be updated.
 *  Output: none.
 *
 * ************************************************************************** **
 */
void update_browser_death_time( struct browse_cache_record *browc )
{
	/* Allow the new lmb to miss an announce period before we remove it. */
	browc->death_time = time(NULL) + ( (CHECK_TIME_MST_ANNOUNCE + 2) * 60 );
}

/* ************************************************************************** **
 * Create a browser entry and add it to the local master browser list.
 *
 *  Input:  work_name
 *          browser_name
 *          ip
 *
 *  Output: Pointer to the new entry, or NULL if malloc() failed.
 *
 * ************************************************************************** **
 */
struct browse_cache_record *create_browser_in_lmb_cache( const char *work_name, 
                                                         const char *browser_name, 
                                                         struct in_addr ip )
{
	struct browse_cache_record *browc;
	time_t now = time( NULL );

	browc = SMB_MALLOC_P(struct browse_cache_record);

	if( NULL == browc ) {
		DEBUG( 0, ("create_browser_in_lmb_cache: malloc fail !\n") );
		return( NULL );
	}

	memset( (char *)browc, '\0', sizeof( *browc ) );
  
	/* For a new lmb entry we want to sync with it after one minute. This
	 will allow it time to send out a local announce and build its
	 browse list.
	*/

	browc->sync_time = now + 60;

	/* Allow the new lmb to miss an announce period before we remove it. */
	browc->death_time = now + ( (CHECK_TIME_MST_ANNOUNCE + 2) * 60 );

	unstrcpy( browc->lmb_name, browser_name);
	unstrcpy( browc->work_group, work_name);
	if (!strupper_m( browc->lmb_name )) {
		SAFE_FREE(browc);
		return NULL;
	}
	if (!strupper_m( browc->work_group )) {
		SAFE_FREE(browc);
		return NULL;
	}
  
	browc->ip = ip;
 
	DLIST_ADD_END(lmb_browserlist, browc);

	DEBUG(3, ("nmbd_browserdb:create_browser_in_lmb_cache()\n"));
	DEBUGADD(3, ("  Added lmb cache entry for workgroup %s name %s IP %s "
		     "ttl %d\n", browc->work_group, browc->lmb_name,
		     inet_ntoa(ip), (int)browc->death_time));
  
	return( browc );
}

/* ************************************************************************** **
 * Find a browser entry in the local master browser list.
 *
 *  Input:  browser_name  - The name for which to search.
 *
 *  Output: A pointer to the matching entry, or NULL if no match was found.
 *
 * ************************************************************************** **
 */
struct browse_cache_record *find_browser_in_lmb_cache( const char *browser_name )
{
	struct browse_cache_record *browc;

	for( browc = lmb_browserlist; browc; browc = browc->next ) {
		if( strequal( browser_name, browc->lmb_name ) ) {
			break;
		}
	}

	return browc;
}

/* ************************************************************************** **
 *  Expire timed out browsers in the browserlist.
 *
 *  Input:  t - Expiration time.  Entries with death times less than this
 *              value will be removed from the list.
 *  Output: none.
 *
 * ************************************************************************** **
 */
void expire_lmb_browsers( time_t t )
{
	struct browse_cache_record *browc;
	struct browse_cache_record *nextbrowc;

	for( browc = lmb_browserlist; browc; browc = nextbrowc) {
		nextbrowc = browc->next;

		if( browc->death_time < t ) {
			DEBUG(3, ("nmbd_browserdb:expire_lmb_browsers()\n"));
			DEBUGADD(3, ("  Removing timed out lmb entry %s\n",
				     browc->lmb_name));
			remove_lmb_browser_entry( browc );
		}
	}
}