clnp_subr.c

早期freebsd实现

	 *	If options are present, update them
	 */
	if (oidx) {
		struct iso_addr	*mysrc = &ia->ia_addr.siso_addr;
		if (mysrc == NULL) {
			clnp_discard(m, ADDR_DESTUNREACH);
			INCSTAT(cns_cantforward);
			clnp_stat.cns_forward--;
			goto done;
		} else {
			(void) clnp_dooptions(m, oidx, ifp, mysrc);
		}
	}

#ifdef	DECBIT
	if (ifp->if_snd.ifq_len > congest_threshold) {
		/*
		 *	Congestion! Set the Dec Bit and thank Dave Oran
		 */
		IFDEBUG(D_FORWARD)
			printf("clnp_forward: congestion experienced\n");
		ENDDEBUG
		if ((oidx) && (oidx->cni_qos_formatp)) {
			caddr_t	qosp = CLNP_OFFTOOPT(m, oidx->cni_qos_formatp);
			u_char	qos = *qosp;
			IFDEBUG(D_FORWARD)
				printf("clnp_forward: setting congestion bit (qos x%x)\n", qos);
			ENDDEBUG
			if ((qos & CLNPOVAL_GLOBAL) == CLNPOVAL_GLOBAL) {
				qos |= CLNPOVAL_CONGESTED;
				INCSTAT(cns_congest_set);
				*qosp = qos;
			}
		}
	}
#endif	/* DECBIT */
	
	/*
	 *	Dispatch the datagram if it is small enough, otherwise fragment
	 */
	if (len <= SN_MTU(ifp, route.ro_rt)) {
		iso_gen_csum(m, CLNP_CKSUM_OFF, (int)clnp->cnf_hdr_len);
		(void) (*ifp->if_output)(ifp, m, next_hop, route.ro_rt);
	} else {
		(void) clnp_fragment(ifp, m, next_hop, len, seg_off, /* flags */0, route.ro_rt);
	}
	
done:
	/*
	 *	Free route
	 */
	if (route.ro_rt != NULL) {
		RTFREE(route.ro_rt);
	}
}

#ifdef	notdef
/*
 * FUNCTION:		clnp_insert_addr
 *
 * PURPOSE:			Insert the address part into a clnp datagram.
 *
 * RETURNS:			Address of first byte after address part in datagram.
 *
 * SIDE EFFECTS:	
 *
 * NOTES:			Assume that there is enough space for the address part.
 */
caddr_t
clnp_insert_addr(bufp, srcp, dstp)
caddr_t						bufp;	/* address of where addr part goes */
register struct iso_addr	*srcp;	/* ptr to src addr */
register struct iso_addr	*dstp;	/* ptr to dst addr */
{
	*bufp++ = dstp->isoa_len;
	(void) bcopy((caddr_t)dstp, bufp, dstp->isoa_len);
	bufp += dstp->isoa_len;

	*bufp++ = srcp->isoa_len;
	(void) bcopy((caddr_t)srcp, bufp, srcp->isoa_len);
	bufp += srcp->isoa_len;

	return bufp;
}

#endif	/* notdef */

/*
 * FUNCTION:		clnp_route
 *
 * PURPOSE:			Route a clnp datagram to the first hop toward its 
 *					destination. In many cases, the first hop will be
 *					the destination. The address of a route
 *					is specified. If a routing entry is present in
 *					that route, and it is still up to the same destination,
 *					then no further action is necessary. Otherwise, a
 *					new routing entry will be allocated.
 *
 * RETURNS:			route found - 0
 *					unix error code
 *
 * SIDE EFFECTS:	
 *
 * NOTES:			It is up to the caller to free the routing entry
 *					allocated in route.
 */
clnp_route(dst, ro, flags, first_hop, ifa)
	struct iso_addr	*dst;			/* ptr to datagram destination */
	register struct	route_iso *ro;	/* existing route structure */
	int flags;						/* flags for routing */
	struct sockaddr **first_hop;	/* result: fill in with ptr to firsthop */
	struct iso_ifaddr **ifa;		/* result: fill in with ptr to interface */
{
	if (flags & SO_DONTROUTE) {
		struct iso_ifaddr *ia;

		if (ro->ro_rt) {
			RTFREE(ro->ro_rt);
			ro->ro_rt = 0;
		}
		bzero((caddr_t)&ro->ro_dst, sizeof(ro->ro_dst));
		bcopy((caddr_t)dst, (caddr_t)&ro->ro_dst.siso_addr,
			1 + (unsigned)dst->isoa_len);
		ro->ro_dst.siso_family = AF_ISO;
		ro->ro_dst.siso_len = sizeof(ro->ro_dst);
		ia = iso_localifa(&ro->ro_dst);
		if (ia == 0)
			return EADDRNOTAVAIL;
		if (ifa)
			*ifa = ia;
		if (first_hop)
			*first_hop = (struct sockaddr *)&ro->ro_dst;
		return 0;
	}
	/*
	 *	If there is a cached route, check that it is still up and to
	 *	the same destination. If not, free it and try again.
	 */
	if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
		(Bcmp(ro->ro_dst.siso_data, dst->isoa_genaddr, dst->isoa_len)))) {
		IFDEBUG(D_ROUTE)
			printf("clnp_route: freeing old route: ro->ro_rt 0x%x\n",
				ro->ro_rt);
			printf("clnp_route: old route refcnt: 0x%x\n",
				ro->ro_rt->rt_refcnt);
		ENDDEBUG

		/* free old route entry */
		RTFREE(ro->ro_rt);
		ro->ro_rt = (struct rtentry *)0;
	} else {
		IFDEBUG(D_ROUTE)
			printf("clnp_route: OK route exists\n");
		ENDDEBUG
	}

	if (ro->ro_rt == 0) {
		/* set up new route structure */
		bzero((caddr_t)&ro->ro_dst, sizeof(ro->ro_dst));
		ro->ro_dst.siso_len = sizeof(ro->ro_dst);
		ro->ro_dst.siso_family = AF_ISO;
		Bcopy(dst, &ro->ro_dst.siso_addr, 1 + dst->isoa_len);
		/* allocate new route */
		IFDEBUG(D_ROUTE)
			printf("clnp_route: allocating new route to %s\n",
				clnp_iso_addrp(dst));
		ENDDEBUG
		rtalloc((struct route *)ro);
	}
	if (ro->ro_rt == 0)
		return(ENETUNREACH);	/* rtalloc failed */
	ro->ro_rt->rt_use++;
	if (ifa)
		if ((*ifa = (struct iso_ifaddr *)ro->ro_rt->rt_ifa) == 0)
			panic("clnp_route");
	if (first_hop) {
		if (ro->ro_rt->rt_flags & RTF_GATEWAY)
			*first_hop = ro->ro_rt->rt_gateway;
		else
			*first_hop = (struct sockaddr *)&ro->ro_dst;
	}
	return(0);
}

/*
 * FUNCTION:		clnp_srcroute
 *
 * PURPOSE:			Source route the datagram. If complete source
 *					routing is specified but not possible, then
 *					return an error. If src routing is terminated, then
 *					try routing on destination.
 *					Usage of first_hop,
 *					ifp, and error return is identical to clnp_route.
 *
 * RETURNS:			0 or unix error code
 *
 * SIDE EFFECTS:	
 *
 * NOTES:			Remember that option index pointers are really
 *					offsets from the beginning of the mbuf.
 */
clnp_srcroute(options, oidx, ro, first_hop, ifa, final_dst)
struct mbuf			*options;		/* ptr to options */
struct clnp_optidx	*oidx;			/* index to options */
struct route_iso	*ro;			/* route structure */
struct sockaddr		**first_hop;	/* RETURN: fill in with ptr to firsthop */
struct iso_ifaddr	**ifa;			/* RETURN: fill in with ptr to interface */
struct iso_addr		*final_dst;		/* final destination */
{
	struct iso_addr	dst;		/* first hop specified by src rt */
	int				error = 0;	/* return code */

	/*
	 *	Check if we have run out of routes 
	 *	If so, then try to route on destination.
	 */
	if CLNPSRCRT_TERM(oidx, options) {
		dst.isoa_len = final_dst->isoa_len;
		bcopy(final_dst->isoa_genaddr, dst.isoa_genaddr, dst.isoa_len);
	} else {
		/*
		 * setup dst based on src rt specified
		 */
		dst.isoa_len = CLNPSRCRT_CLEN(oidx, options);
		bcopy(CLNPSRCRT_CADDR(oidx, options), dst.isoa_genaddr, dst.isoa_len);
	}

	/*
	 *	try to route it
	 */
	error = clnp_route(&dst, ro, 0, first_hop, ifa);
	if (error != 0)
		return error;
	
	/*
	 *	If complete src rt, first hop must be equal to dst
	 */
	if ((CLNPSRCRT_TYPE(oidx, options) == CLNPOVAL_COMPRT) &&
	 (!iso_addrmatch1(&(*(struct sockaddr_iso **)first_hop)->siso_addr,&dst))){
		IFDEBUG(D_OPTIONS)
			printf("clnp_srcroute: complete src route failed\n");
		ENDDEBUG
		return EHOSTUNREACH; /* RAH? would like ESRCRTFAILED */
	}
	
	return error;
}

/*
 * FUNCTION:		clnp_echoreply
 *
 * PURPOSE:			generate an echo reply packet and transmit
 *
 * RETURNS:			result of clnp_output
 *
 * SIDE EFFECTS:	
 */
clnp_echoreply(ec_m, ec_len, ec_src, ec_dst, ec_oidxp)
struct mbuf			*ec_m;		/* echo request */
int					ec_len;		/* length of ec */
struct sockaddr_iso	*ec_src;		/* src of ec */
struct sockaddr_iso	*ec_dst; 	/* destination of ec (i.e., us) */
struct clnp_optidx	*ec_oidxp;	/* options index to ec packet */
{
	struct isopcb	isopcb;
	int				flags = CLNP_NOCACHE|CLNP_ECHOR;
	int				ret;

	/* fill in fake isopcb to pass to output function */
	bzero(&isopcb, sizeof(isopcb));
	isopcb.isop_laddr = ec_dst;
	isopcb.isop_faddr = ec_src;

	/* forget copying the options for now. If implemented, need only
	 * copy record route option, but it must be reset to zero length */

	ret = clnp_output(ec_m, &isopcb, ec_len, flags);

	IFDEBUG(D_OUTPUT)
		printf("clnp_echoreply: output returns %d\n", ret);
	ENDDEBUG
	return ret;
}

/*
 * FUNCTION:		clnp_badmtu
 *
 * PURPOSE:			print notice of route with mtu not initialized.
 *
 * RETURNS:			mtu of ifp.
 *
 * SIDE EFFECTS:	prints notice, slows down system.
 */
clnp_badmtu(ifp, rt, line, file)
struct ifnet *ifp;	/* outgoing interface */
struct rtentry *rt; /* dst route */
int line;			/* where the dirty deed occured */
char *file;			/* where the dirty deed occured */
{
	printf("sending on route 0x%x with no mtu, line %d of file %s\n",
		rt, line, file);
#ifdef ARGO_DEBUG
	printf("route dst is ");
	dump_isoaddr(rt_key(rt));
#endif
	return ifp->if_mtu;
}

/*
 * FUNCTION:		clnp_ypocb - backwards bcopy
 *
 * PURPOSE:			bcopy starting at end of src rather than beginning.
 *
 * RETURNS:			none
 *
 * SIDE EFFECTS:	
 *
 * NOTES:			No attempt has been made to make this efficient
 */
clnp_ypocb(from, to, len)
caddr_t from;		/* src buffer */
caddr_t to;			/* dst buffer */
u_int	len;		/* number of bytes */
{
	while (len--)
		*(to + len) = *(from + len);
}
#endif	/* ISO */