path: root/sbin/routed/defs.h

/*	$OpenBSD: defs.h,v 1.7 2001/11/06 21:29:28 jakob Exp $	*/

/*
 * Copyright (c) 1983, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)defs.h	8.1 (Berkeley) 6/5/93
 *
 */

/* Definitions for RIPv2 routing process.
 *
 * This code is based on the 4.4BSD `routed` daemon, with extensions to
 * support:
 *	RIPv2, including variable length subnet masks.
 *	Router Discovery
 *	aggregate routes in the kernel tables.
 *	aggregate advertised routes.
 *	maintain spare routes for faster selection of another gateway
 *		when the current gateway dies.
 *	timers on routes with second granularity so that selection
 *		of a new route does not wait 30-60 seconds.
 *	tolerance of static routes.
 *	tell the kernel hop counts
 *	do not advertise if ipforwarding=0
 *
 * The vestigual support for other protocols has been removed.  There
 * is no likelihood that IETF RIPv1 or RIPv2 will ever be used with
 * other protocols.  The result is far smaller, faster, cleaner, and
 * perhaps understandable.
 *
 * The accumulation of special flags and kludges added over the many
 * years have been simplified and integrated.
 */

#include <stdio.h>
#include <netdb.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdarg.h>
#include <syslog.h>
#include <time.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <net/radix.h>
#include <net/if.h>
#include <net/route.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define RIPVERSION RIPv2
#include <protocols/routed.h>


/* Type of an IP address.
 *	Some systems do not like to pass structures, so do not use in_addr.
 *	Some systems think a long has 64 bits, which would be a gross waste.
 * So define it here so it can be changed for the target system.
 * It should be defined somewhere netinet/in.h, but it is not.
 */
#define naddr u_int32_t
#define _HAVE_SA_LEN
#define _HAVE_SIN_LEN

/* Turn on if IP_DROP_MEMBERSHIP and IP_ADD_MEMBERSHIP do not look at
 * the dstaddr of point-to-point interfaces.
 */
/* #define MCAST_PPP_BUG */

#define NEVER (24*60*60)		/* a long time */
#define EPOCH NEVER			/* bias time by this to avoid <0 */

/* Scan the kernel regularly to see if any interfaces have appeared or been
 * turned off.  These must be less than STALE_TIME.
 */
#define	CHECK_BAD_INTERVAL	5	/* when an interface is known bad */
#define	CHECK_ACT_INTERVAL	30	/* when advertising */
#define	CHECK_QUIET_INTERVAL	300	/* when not */

#define LIM_SEC(s,l) ((s).tv_sec = MIN((s).tv_sec, (l)))


/* Router Discovery parameters */
#ifndef sgi
#ifndef INADDR_ALLROUTERS_GROUP
#define INADDR_ALLROUTERS_GROUP		0xe0000002  /* 224.0.0.2 */
#endif
#endif
#define	MaxMaxAdvertiseInterval		1800
#define	MinMaxAdvertiseInterval		4
#define	DefMaxAdvertiseInterval		600
#define DEF_PreferenceLevel		0
#define MIN_PreferenceLevel		0x80000000

#define	MAX_INITIAL_ADVERT_INTERVAL	16
#define	MAX_INITIAL_ADVERTS		3
#define	MAX_RESPONSE_DELAY		2

#define	MAX_SOLICITATION_DELAY		1
#define	SOLICITATION_INTERVAL		3
#define	MAX_SOLICITATIONS		3


/* typical packet buffers */
union pkt_buf {
	char	packet[MAXPACKETSIZE+1];
	struct	rip rip;
};


/* no more routes than this, to protect ourself in case something goes
 * whacko and starts broadcast zillions of bogus routes.
 */
#define MAX_ROUTES  (128*1024)
extern int total_routes;

/* Main, daemon routing table structure
 */
struct rt_entry {
	struct	radix_node rt_nodes[2];	/* radix tree glue */
	u_int	rt_state;
#	    define RS_IF	0x001	/* for network interface */
#	    define RS_NET_INT	0x002	/* authority route */
#	    define RS_NET_SYN	0x004	/* fake net route for subnet */
#	    define RS_NO_NET_SYN (RS_LOCAL | RS_LOCAL | RS_IF)
#	    define RS_SUBNET	0x008	/* subnet route from any source */
#	    define RS_LOCAL	0x010	/* loopback for pt-to-pt */
#	    define RS_MHOME	0x020	/* from -m */
#	    define RS_STATIC	0x040	/* from the kernel */
#	    define RS_RDISC     0x080	/* from router discovery */
	struct sockaddr_in rt_dst_sock;
	naddr   rt_mask;
	struct rt_spare {
	    struct interface *rts_ifp;
	    naddr   rts_gate;		/* forward packets here */
	    naddr   rts_router;		/* on the authority of this router */
	    char    rts_metric;
	    u_short rts_tag;
	    time_t  rts_time;		/* timer to junk stale routes */
#define NUM_SPARES 4
	} rt_spares[NUM_SPARES];
	u_int	rt_seqno;		/* when last changed */
	char	rt_poison_metric;	/* to notice maximum recently */
	time_t	rt_poison_time;		/*	advertised metric */
};
#define rt_dst	rt_dst_sock.sin_addr.s_addr
#define rt_ifp	rt_spares[0].rts_ifp
#define rt_gate	rt_spares[0].rts_gate
#define rt_router rt_spares[0].rts_router
#define rt_metric rt_spares[0].rts_metric
#define rt_tag	rt_spares[0].rts_tag
#define rt_time	rt_spares[0].rts_time

#define HOST_MASK	0xffffffff
#define RT_ISHOST(rt)	((rt)->rt_mask == HOST_MASK)

/* age all routes that
 *	are not from -g, -m, or static routes from the kernel
 *	not unbroken interface routes
 *		but not broken interfaces
 *	nor non-passive, remote interfaces that are not aliases
 *		(i.e. remote & metric=0)
 */
#define AGE_RT(rt_state,ifp) (0 == ((rt_state) & (RS_MHOME | RS_STATIC	    \
						  | RS_NET_SYN | RS_RDISC)) \
			      && (!((rt_state) & RS_IF)			    \
				  || (ifp) == 0				    \
				  || (((ifp)->int_state & IS_REMOTE)	    \
				      && !((ifp)->int_state & IS_PASSIVE))))

/* true if A is better than B
 * Better if
 *	- A is not a poisoned route
 *	- and A is not stale
 *	- and A has a shorter path
 *		- or is the router speaking for itself
 *		- or the current route is equal but stale
 *		- or it is a host route advertised by a system for itself
 */
#define BETTER_LINK(rt,A,B) ((A)->rts_metric < HOPCNT_INFINITY	\
			     && now_stale <= (A)->rts_time		\
			     && ((A)->rts_metric < (B)->rts_metric	\
				 || ((A)->rts_gate == (A)->rts_router	\
				     && (B)->rts_gate != (B)->rts_router) \
				 || ((A)->rts_metric == (B)->rts_metric	\
				     && now_stale > (B)->rts_time)	\
				 || (RT_ISHOST(rt)			\
				     && (rt)->rt_dst == (A)->rts_router	\
				     && (A)->rts_metric == (B)->rts_metric)))


/* An "interface" is similar to a kernel ifnet structure, except it also
 * handles "logical" or "IS_REMOTE" interfaces (remote gateways).
 */
struct interface {
	struct	interface *int_next, *int_prev;
	char	int_name[IFNAMSIZ+15+1];    /* big enough for IS_REMOTE */
	u_short	int_index;
	naddr	int_addr;		/* address on this host (net order) */
	naddr	int_brdaddr;		/* broadcast address (n) */
	naddr	int_dstaddr;		/* other end of pt-to-pt link (n) */
	naddr	int_net;		/* working network # (host order)*/
	naddr	int_mask;		/* working net mask (host order) */
	naddr	int_ripv1_mask;		/* for inferring a mask (n) */
	naddr	int_std_addr;		/* class A/B/C address (n) */
	naddr	int_std_net;		/* class A/B/C network (h) */
	naddr	int_std_mask;		/* class A/B/C netmask (h) */
	int	int_rip_sock;		/* for queries */
	int	int_if_flags;		/* some bits copied from kernel */
	u_int	int_state;
	time_t	int_act_time;		/* last thought healthy */
	u_short	int_transitions;	/* times gone up-down */
	char	int_metric;
	char	int_d_metric;		/* for faked default route */
	struct int_data {
		u_int	ipackets;	/* previous network stats */
		u_int	ierrors;
		u_int	opackets;
		u_int	oerrors;
#ifdef sgi
		u_int	odrops;
#endif
		time_t	ts;		/* timestamp on network stats */
	} int_data;
	char	int_passwd[RIP_AUTH_PW_LEN];	/* RIPv2 password */
	int	int_rdisc_pref;		/* advertised rdisc preference */
	int	int_rdisc_int;		/* MaxAdvertiseInterval */
	int	int_rdisc_cnt;
	struct timeval int_rdisc_timer;
};

/* bits in int_state */
#define IS_ALIAS	    0x0000001	/* interface alias */
#define IS_SUBNET	    0x0000002	/* interface on subnetted network */
#define	IS_REMOTE	    0x0000004	/* interface is not on this machine */
#define	IS_PASSIVE	    0x0000008	/* remote and does not do RIP */
#define IS_EXTERNAL	    0x0000010	/* handled by EGP or something */
#define IS_CHECKED	    0x0000020	/* still exists */
#define IS_ALL_HOSTS	    0x0000040	/* in INADDR_ALLHOSTS_GROUP */
#define IS_ALL_ROUTERS	    0x0000080	/* in INADDR_ALLROUTERS_GROUP */
#define IS_RIP_QUERIED	    0x0000100	/* query broadcast */
#define IS_BROKE	    0x0000200	/* seems to be broken */
#define IS_SICK		    0x0000400	/* seems to be broken */
#define IS_DUP		    0x0000800	/* has a duplicate address */
#define IS_ACTIVE	    0x0001000	/* heard from it at least once */
#define IS_NEED_NET_SYN	    0x0002000	/* need RS_NET_SYN route */
#define IS_NO_AG	    0x0004000	/* do not aggregate subnets */
#define IS_NO_SUPER_AG	    0x0008000	/* do not aggregate networks */
#define IS_NO_RIPV1_IN	    0x0010000	/* no RIPv1 input at all */
#define IS_NO_RIPV2_IN	    0x0020000	/* no RIPv2 input at all */
#define IS_NO_RIP_IN	(IS_NO_RIPV1_IN | IS_NO_RIPV2_IN)
#define IS_RIP_IN_OFF(s) (((s) & IS_NO_RIP_IN) == IS_NO_RIP_IN)
#define IS_NO_RIPV1_OUT	    0x0040000	/* no RIPv1 output at all */
#define IS_NO_RIPV2_OUT	    0x0080000	/* no RIPv2 output at all */
#define IS_NO_RIP_OUT	(IS_NO_RIPV1_OUT | IS_NO_RIPV2_OUT)
#define IS_NO_RIP	(IS_NO_RIP_OUT | IS_NO_RIP_IN)
#define IS_RIP_OUT_OFF(s) (((s) & IS_NO_RIP_OUT) == IS_NO_RIP_OUT)
#define IS_RIP_OFF(s)	(((s) & IS_NO_RIP) == IS_NO_RIP)
#define IS_NO_ADV_IN	    0x0100000
#define IS_NO_SOL_OUT	    0x0200000	/* no solicitations */
#define IS_SOL_OUT	    0x0400000	/* send solicitations */
#define GROUP_IS_SOL	(IS_NO_ADV_IN|IS_NO_SOL_OUT)
#define IS_NO_ADV_OUT	    0x0800000	/* do not advertise rdisc */
#define IS_ADV_OUT	    0x1000000	/* advertise rdisc */
#define GROUP_IS_ADV	(IS_NO_ADV_OUT|IS_ADV_OUT)
#define IS_BCAST_RDISC	    0x2000000	/* broadcast instead of multicast */
#define IS_NO_RDISC	(IS_NO_ADV_IN | IS_NO_SOL_OUT | IS_NO_ADV_OUT)
#define IS_PM_RDISC	    0x4000000	/* poor-man's router discovery */

#ifdef sgi
#define IFF_UP_RUNNING (IFF_RUNNING|IFF_UP)
#else
#define IFF_UP_RUNNING IFF_UP
#endif
#define iff_alive(f) (((f) & IFF_UP_RUNNING) == IFF_UP_RUNNING)


/* Information for aggregating routes */
#define NUM_AG_SLOTS	32
struct ag_info {
	struct ag_info *ag_fine;	/* slot with finer netmask */
	struct ag_info *ag_cors;	/* more coarse netmask */
	naddr	ag_dst_h;		/* destination in host byte order */
	naddr	ag_mask;
	naddr	ag_gate;
	naddr	ag_nhop;
	char	ag_metric;		/* metric to be advertised */
	char	ag_pref;		/* aggregate based on this */
	u_int	ag_seqno;
	u_short	ag_tag;
	u_short	ag_state;
#define	    AGS_SUPPRESS    0x001	/* combine with coaser mask */
#define	    AGS_PROMOTE	    0x002	/* synthesize combined routes */
#define	    AGS_REDUN0	    0x004	/* redundant, finer routes output */
#define	    AGS_REDUN1	    0x008
#define	    AG_IS_REDUN(state) (((state) & (AGS_REDUN0 | AGS_REDUN1)) \
				== (AGS_REDUN0 | AGS_REDUN1))
#define	    AGS_GATEWAY	    0x010	/* tell kernel RTF_GATEWAY */
#define	    AGS_IF	    0x020	/* for an interface */
#define	    AGS_RIPV2	    0x040	/* send only as RIPv2 */
#define	    AGS_FINE_GATE   0x080	/* ignore differing ag_gate when this
					 * has the finer netmask */
#define	    AGS_CORS_GATE   0x100	/* ignore differing gate when this
					 * has the coarser netmaks */
#define	    AGS_SPLIT_HZ    0x200	/* suppress for split horizon */

	/* some bits are set if they are set on either route */
#define	    AGS_PROMOTE_EITHER (AGS_RIPV2 | AGS_GATEWAY |   \
				AGS_SUPPRESS | AGS_CORS_GATE)
};


/* parameters for interfaces */
extern struct parm {
	struct parm *parm_next;
	char	parm_name[IFNAMSIZ+1];
	naddr	parm_addr_h;
	naddr	parm_mask;

	char	parm_d_metric;
	u_int	parm_int_state;
	int	parm_rdisc_pref;
	int	parm_rdisc_int;
	char	parm_passwd[RIP_AUTH_PW_LEN+1];
} *parms;

/* authority for internal networks */
extern struct intnet {
	struct intnet *intnet_next;
	naddr	intnet_addr;
	naddr	intnet_mask;
	char	intnet_metric;
} *intnets;



extern pid_t	mypid;
extern naddr	myaddr;			/* main address of this system */

extern int	stopint;		/* !=0 to stop */

extern int	sock_max;
extern int	rip_sock;		/* RIP socket */
extern struct interface *rip_sock_mcast;    /* current multicast interface */
extern int	rt_sock;		/* routing socket */
extern int	rt_sock_seqno;
extern int	rdisc_sock;		/* router-discovery raw socket */

extern int	seqno;			/* sequence number for messages */
extern int	supplier;		/* process should supply updates */
extern int	lookforinterfaces;	/* 1=probe for new up interfaces */
extern int	supplier_set;		/* -s or -q requested */
extern int	ridhosts;		/* 1=reduce host routes */
extern int	mhome;			/* 1=want multi-homed host route */
extern int	advertise_mhome;	/* 1=must continue adverising it */
extern int	auth_ok;		/* 1=ignore auth if we do not care */

extern struct timeval epoch;		/* when started */
extern struct timeval now;		/* current idea of time */
extern time_t	now_stale;
extern time_t	now_expire;
extern time_t	now_garbage;

extern struct timeval next_bcast;	/* next general broadcast */
extern struct timeval age_timer;	/* next check of old routes */
extern struct timeval no_flash;		/* inhibit flash update until then */
extern struct timeval rdisc_timer;	/* next advert. or solicitation */
extern int rdisc_ok;			/* using solicited route */

extern struct timeval ifinit_timer;	/* time to check interfaces */

extern naddr	loopaddr;		/* our address on loopback */
extern int	tot_interfaces;		/* # of remote and local interfaces */
extern int	rip_interfaces;		/* # of interfaces doing RIP */
extern struct interface *ifnet;		/* all interfaces */
extern int	have_ripv1_out;		/* have a RIPv1 interface */
extern int	have_ripv1_in;
extern int	need_flash;		/* flash update needed */
extern struct timeval need_kern;	/* need to update kernel table */
extern int	update_seqno;		/* a route has changed */

extern u_int	tracelevel, new_tracelevel;
#define MAX_TRACELEVEL 4
#define TRACEKERNEL (tracelevel >= 4)	/* log kernel changes */
#define	TRACECONTENTS (tracelevel >= 3)	/* display packet contents */
#define TRACEPACKETS (tracelevel >= 2)	/* note packets */
#define	TRACEACTIONS (tracelevel != 0)
extern FILE	*ftrace;		/* output trace file */

extern struct radix_node_head *rhead;


#ifdef sgi
/* Fix conflicts */
#define	dup2(x,y)		BSDdup2(x,y)
#endif /* sgi */

extern void fix_sock(int, char *);
extern void fix_select(void);
extern void rip_off(void);
extern void rip_on(struct interface *);

enum output_type {OUT_QUERY, OUT_UNICAST, OUT_BROADCAST, OUT_MULTICAST,
	NO_OUT_MULTICAST, NO_OUT_RIPV2};
extern int	output(enum output_type, struct sockaddr_in *,
		       struct interface *, struct rip *, int);
extern void rip_query(void);
extern void rip_bcast(int);
extern void supply(struct sockaddr_in *, struct interface *,
		   enum output_type, int, int);

extern void	msglog(char *, ...);
#define	LOGERR(msg) msglog(msg ": %s", strerror(errno))
extern void	logbad(int, char *, ...);
#define	BADERR(dump,msg) logbad(dump,msg ": %s", strerror(errno))
#ifdef DEBUG
#define	DBGERR(dump,msg) BADERR(dump,msg)
#else
#define	DBGERR(dump,msg) LOGERR(msg)
#endif
extern	char	*naddr_ntoa(naddr);
extern	char	*saddr_ntoa(struct sockaddr *);

extern void	*rtmalloc(size_t, char *);
extern void	timevaladd(struct timeval *, struct timeval *);
extern void	intvl_random(struct timeval *, u_long, u_long);
extern int	getnet(char *, naddr *, naddr *);
extern int	gethost(char *, naddr *);
extern void	gwkludge(void);
extern char	*parse_parms(char *);
extern char	*check_parms(struct parm *);
extern void	get_parms(struct interface *);

extern void	lastlog(void);
extern void	trace_on(char *, int);
extern void	trace_off(char*, ...);
extern void	trace_flush(void);
extern void	set_tracelevel(void);
extern void	trace_kernel(char *, ...);
extern void	trace_act(char *, ...);
extern void	trace_pkt(char *, ...);
extern void	trace_add_del(char *, struct rt_entry *);
extern void	trace_change(struct rt_entry *, u_int, naddr, naddr, int,
			     u_short, struct interface *, time_t, char *);
extern void	trace_if(char *, struct interface *);
extern void	trace_upslot(struct rt_entry *, struct rt_spare *,
			     naddr, naddr,
			     struct interface *, int, u_short, time_t);
extern void	trace_rip(char*, char*, struct sockaddr_in *,
			  struct interface *, struct rip *, int);
extern char	*addrname(naddr, naddr, int);

extern void	rdisc_age(naddr);
extern void	set_rdisc_mg(struct interface *, int);
extern void	set_supplier(void);
extern void	if_bad_rdisc(struct interface *);
extern void	if_ok_rdisc(struct interface *);
extern void	read_rip(int, struct interface *);
extern void	read_rt(void);
extern void	read_d(void);
extern void	rdisc_adv(void);
extern void	rdisc_sol(void);

extern void	sigalrm(int);
extern void	sigterm(int);

extern void	sigtrace_on(int);
extern void	sigtrace_off(int);

extern void	flush_kern(void);
extern void	age(naddr);

extern void	ag_flush(naddr, naddr, void (*)(struct ag_info *));
extern void	ag_check(naddr, naddr, naddr, naddr, char, char, u_int,
			 u_short, u_short, void (*)(struct ag_info *));
extern void	del_static(naddr, naddr, int);
extern void	del_redirects(naddr, time_t);
extern struct rt_entry *rtget(naddr, naddr);
extern struct rt_entry *rtfind(naddr);
extern void	rtinit(void);
extern void	rtadd(naddr, naddr, naddr, naddr,
		      int, u_short, u_int, struct interface *);
extern void	rtchange(struct rt_entry *, u_int, naddr,naddr, int, u_short,
			 struct interface *ifp, time_t, char *);
extern void	rtdelete(struct rt_entry *);
extern void	rtbad_sub(struct rt_entry *);
extern void	rtswitch(struct rt_entry *, struct rt_spare *);
extern void	rtbad(struct rt_entry *);


#define S_ADDR(x)	(((struct sockaddr_in *)(x))->sin_addr.s_addr)
#define INFO_DST(I)	((I)->rti_info[RTAX_DST])
#define INFO_GATE(I)	((I)->rti_info[RTAX_GATEWAY])
#define INFO_MASK(I)	((I)->rti_info[RTAX_NETMASK])
#define INFO_IFA(I)	((I)->rti_info[RTAX_IFA])
#define INFO_IFP(I)	((I)->rti_info[RTAX_IFP])
#define INFO_AUTHOR(I)	((I)->rti_info[RTAX_AUTHOR])
#define INFO_BRD(I)	((I)->rti_info[RTAX_BRD])
void rt_xaddrs(struct rt_addrinfo *, struct sockaddr *, struct sockaddr *,
	       int);

extern naddr	std_mask(naddr);
extern naddr	ripv1_mask_net(naddr, struct interface *);
extern naddr	ripv1_mask_host(naddr,struct interface *);
#define		on_net(a,net,mask) (((ntohl(a) ^ (net)) & (mask)) == 0)
extern int	check_dst(naddr);
extern void	addrouteforif(register struct interface *);
extern void	ifinit(void);
extern int	walk_bad(struct radix_node *, void *);
extern int	if_ok(struct interface *, char *);
extern void	if_sick(struct interface *);
extern void	if_bad(struct interface *);
extern struct interface *ifwithaddr(naddr, int, int);
extern struct interface *ifwithname(char *, naddr);
extern struct interface *ifwithindex(u_short);
extern struct interface *iflookup(naddr);