fa_hash.h

mobile ip 在linux下的一种实现

/* $Id: fa_hash.h,v 1.3 2000/04/06 07:26:51 jm Exp $
 * Foreign Agent - lower FA hash
 *
 * Dynamic hierarchial IP tunnel
 * Copyright (C) 1998-2000, Dynamics group
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation. See README and COPYING for
 * more details.
 */

#ifndef FA_HASH_H
#define FA_HASH_H

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "message.h"
#include "msgparser.h"

/* number of seconds after which a timed out, confirmed entry from the FA
 * hash table _may_ be removed; unconfirmed entries are removed after they
 * have timed out (i.e. this extra time is not used) */
#define FA_HASH_EXPIRE_TIME (3600*12)


/* dynamically generated hashtable of the next lower FAs */
struct next_hop_data {
	struct node node;
	struct in_addr addr;
	time_t expire;
};

/* dynamically generated hashtable of all the FAs that are below this FA */
struct lower_fa_data {
	struct node node;

	int nai_len; /* FA NAI length (number of characters in 'nai' variable)
		      */
	char nai[MAX_NAI_LEN];


	/* information about the last _accepted_ FA registration */

	struct interface_entry *iface; /* the interface from which the
					* FA reg. request was received */
	struct sockaddr_in from; /* req. source address */

	time_t reply_time; /* timestamp of the last acceptance reply */
	time_t expire;
	__u16 lifetime;
	int confirmed; /* 1 = data confirmed (i.e. acceptance reply received
			* from HFA or this node is the HFA and has accepted the
			* request) */


	/* unconfirmed information of the last FA request */

	time_t req_time; /* timestamp of the request */
	__u16 req_lifetime; /* requested lifetime */
	struct interface_entry *req_iface; /* the incoming interface or
					    * NULL = no pending request */
	struct sockaddr_in req_from; /* source address */
	__u8 use_nonce_down[FA_REG_NONCE_LEN]; /* the nonce value received in
						* a request; to be copied to
						* the next reply */
	__u8 use_nonce_up[FA_REG_NONCE_LEN]; /* the nonce value received in
					      * a reply; to be copied to
					      * the next request */


	/* the nonce value sent upwards in the request; reply must match with
	 * this */
	__u8 wait_nonce_rep[FA_REG_NONCE_LEN];

	/* the nonce value expected to be receive in the next request;
	 * next request must match with this or the request is denied and
	 * the nonces are resynchronized */
	__u8 wait_nonce_req[FA_REG_NONCE_LEN];
};


int fa_hash_init(void);
void fa_hash_destroy(void);
struct interface_entry* fa_hash_check(struct fa_nai_ext *nai);
int fa_hash_check_next_hop(struct in_addr addr);
void fa_hash_expire(void);

enum { FA_REGISTER, FA_DEREGISTER };
void fa_register(int dereg);
int handle_fa_req(char *msg, int n, struct msg_extensions *ext,
		  struct sockaddr_in *cli_addr,
		  struct interface_entry *iface);
int handle_fa_rep(char *msg, int n, struct msg_extensions *ext,
		  struct sockaddr_in *cli_addr,
		  struct interface_entry *iface);

#endif