Source to bsd/netat/at_ddp_brt.h

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */

/*
 *	Copyright (c) 1988, 1989 Apple Computer, Inc. 
 */

#ifndef _NETAT_AT_DDP_BRT_H_
#define _NETAT_AT_DDP_BRT_H_

typedef struct {
	int 				age_flag;
	at_ifaddr_t			*ifID;
	union	{
		struct	etalk_addr	addr1;
		struct	atalk_addr	addr2;
	} addrs;
	at_net_al			net;
#define et_addr	addrs.addr1
#define at_addr	addrs.addr2
} ddp_brt_t;

#define BRT_SWEEP_INT		(10 * PR_SLOWHZ)
#define	BRT_BSIZ		 4	/* bucket size */
#define	BRT_NB			16	/* number of buckets */
#define	BRTSIZE			(BRT_BSIZ * BRT_NB)

/* age_flag values */
#define	BRT_EMPTY		0	/* the BRT entry is empty     */
					/* (or aged out).             */
#define	BRT_VALID		1	/* BRT entry contains valid   */
					/* tuple 		      */
#define	BRT_GETTING_OLD		2	/* BRT entry is a candidate   */
					/* for aging		      */

#define	BRT_HASH(a)   ((a) % BRT_NB)

#define	BRT_LOOK(brt, dst_net) {				\
	register n; 						\
	brt = &at_ddp_brt[BRT_HASH(dst_net) * BRT_BSIZ];	\
	for (n = 0 ; ; brt++) {		                        \
		if (brt->net == dst_net) 			\
			break; 					\
		if (++n >= BRT_BSIZ) {                          \
		        brt = NULL;                             \
			break;                                  \
		}                                               \
	}                                                       \
	}

#define	NEW_BRT(brt, net) {					\
	register n; 						\
	brt = &at_ddp_brt[BRT_HASH(net) * BRT_BSIZ]; 		\
	for (n = 0 ; ; brt++) { 		                \
		if (brt->age_flag == BRT_EMPTY)			\
			break; 					\
		if (++n >= BRT_BSIZ) {				\
		        brt = NULL;				\
			break;                                  \
		}                                               \
        }                                                       \
	}

/* Best Router Cache */
extern	ddp_brt_t	at_ddp_brt[BRTSIZE];

#endif /* _NETAT_AT_DDP_BRT_H_ */