[unix-history] / usr / src / sys / netiso / clnp_er.c

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)clnp_er.c	7.8 (Berkeley) %G%
 */

/***********************************************************
		Copyright IBM Corporation 1987

                      All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the name of IBM not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

******************************************************************/

/*
 * ARGO Project, Computer Sciences Dept., University of Wisconsin - Madison
 */
/* $Header: /var/src/sys/netiso/RCS/clnp_er.c,v 5.1 89/02/09 16:20:18 hagens Exp $ */
/* $Source: /var/src/sys/netiso/RCS/clnp_er.c,v $ */

#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>

#include <net/if.h>
#include <net/route.h>

#include <netiso/iso.h>
#include <netiso/iso_var.h>
#include <netiso/iso_pcb.h>
#define CLNP_ER_CODES
#include <netiso/clnp.h>
#include <netiso/clnp_stat.h>
#include <netiso/argo_debug.h>

static struct clnp_fixed er_template = {
	ISO8473_CLNP,	/* network identifier */
	0,				/* length */
	ISO8473_V1,		/* version */
	CLNP_TTL,		/* ttl */
	CLNP_ER,		/* type */
	0,				/* segment length */
	0				/* checksum */
};

/*
 * FUNCTION:		clnp_er_input
 *
 * PURPOSE:			Process an ER pdu.
 *
 * RETURNS:			
 *
 * SIDE EFFECTS:	
 *
 * NOTES:			
 */
clnp_er_input(m, src, reason)
struct mbuf		*m;		/* ptr to packet itself */
struct iso_addr	*src;	/* ptr to src of er */
u_char			reason;	/* reason code of er */
{
	int	cmd = -1;
	extern u_char clnp_protox[];

	IFDEBUG(D_CTLINPUT)
		printf("clnp_er_input: m x%x, src %s, reason x%x\n", m, 
			clnp_iso_addrp(src), reason);
	ENDDEBUG

	INCSTAT(cns_er_inhist[clnp_er_index(reason)]);
	switch (reason) {
		case GEN_NOREAS:
		case GEN_PROTOERR:
			break;
		case GEN_BADCSUM:		
			cmd = PRC_PARAMPROB;
			break;
		case GEN_CONGEST:		
			cmd = PRC_QUENCH;
			break;
		case GEN_HDRSYNTAX:		
			cmd = PRC_PARAMPROB;
			break;
		case GEN_SEGNEEDED:		
			cmd = PRC_MSGSIZE; 
			break;
		case GEN_INCOMPLETE:	
			cmd = PRC_PARAMPROB; 		
			break;
		case GEN_DUPOPT:		
			cmd = PRC_PARAMPROB;		
			break;
		case ADDR_DESTUNREACH:	
			cmd = PRC_UNREACH_HOST; 	
			break;
		case ADDR_DESTUNKNOWN:	
			cmd = PRC_UNREACH_PROTOCOL; 
			break;
		case SRCRT_UNSPECERR:
		case SRCRT_SYNTAX:
		case SRCRT_UNKNOWNADDR:
		case SRCRT_BADPATH:
			cmd = PRC_UNREACH_SRCFAIL;
			break;
		case TTL_EXPTRANSIT:	
			cmd = PRC_TIMXCEED_INTRANS;	
			break;
		case TTL_EXPREASS:		
			cmd = PRC_TIMXCEED_REASS;	
			break;
		case DISC_UNSUPPOPT:
		case DISC_UNSUPPVERS:
		case DISC_UNSUPPSECURE:
		case DISC_UNSUPPSRCRT:
		case DISC_UNSUPPRECRT:
			cmd = PRC_PARAMPROB; 
			break;
		case REASS_INTERFERE:	
			cmd = PRC_TIMXCEED_REASS;
			break;
	}

	/*
	 *	tpclnp_ctlinput1 is called directly so that we don't
	 *	have to build an iso_sockaddr out of src.
	 */
	if (cmd >= 0)
		tpclnp_ctlinput1(cmd, src);

	m_freem(m);
}

/*
 * FUNCTION:		clnp_discard
 *
 * PURPOSE:			Discard a clnp datagram
 *
 * RETURNS:			nothing
 *
 * SIDE EFFECTS:	Will emit an ER pdu if possible
 *
 * NOTES:			This code assumes that we have previously tried to pull
 *					up the header of the datagram into one mbuf.
 */
clnp_discard(m, reason)
struct mbuf	*m;		/* header of packet to discard */
char					reason;	/* reason for discard */
{
	IFDEBUG(D_DISCARD)
		printf("clnp_discard: m x%x, reason x%x\n", m, reason);
	ENDDEBUG

	if (m != NULL) {
		if (m->m_len >= sizeof(struct clnp_fixed)) {
			register struct clnp_fixed *clnp = mtod(m, struct clnp_fixed *);

			if (((clnp->cnf_type & CNF_TYPE) != CLNP_ER) &&
				(clnp->cnf_type & CNF_ERR_OK)) {
					clnp_emit_er(m, reason);
					return;
			}
		}
		m_freem(m);
	}
}

/*
 * FUNCTION:		clnp_emit_er
 *
 * PURPOSE:			Send an ER pdu.
 *					The src of the of the ER pdu is the host that is sending
 *					the ER (ie. us), *not* the original destination of the
 *					packet.
 *
 * RETURNS:			nothing
 *
 * SIDE EFFECTS:	
 *
 * NOTES:			Takes responsibility for freeing mbuf passed
 *					This function may be called with a packet that
 *					was created by us; in this case, do not send
 *					an ER.
 */
clnp_emit_er(m, reason)
struct mbuf	*m;		/* header of packet to discard */
char					reason;	/* reason for discard */
{
	register struct clnp_fixed	*clnp = mtod(m, struct clnp_fixed *);
	register struct clnp_fixed	*er;
	struct route_iso			route;
	struct ifnet				*ifp;
	struct sockaddr				*first_hop;
	struct iso_addr				src, dst, *our_addr;
	caddr_t						hoff, hend;
	int							total_len;		/* total len of dg */
	struct mbuf 				*m0;			/* contains er pdu hdr */
	struct iso_ifaddr			*ia = 0;

	IFDEBUG(D_DISCARD)
		printf("clnp_emit_er: m x%x, hdr len %d\n", m, clnp->cnf_hdr_len);
	ENDDEBUG

	bzero((caddr_t)&route, sizeof(route));

	/*
	 *	If header length is incorrect, or entire header is not contained
	 *	in this mbuf, we punt
	 */
	if ((clnp->cnf_hdr_len < CLNP_HDR_MIN) ||
		(clnp->cnf_hdr_len > CLNP_HDR_MAX) ||
		(clnp->cnf_hdr_len > m->m_len))
		goto bad;
	
	/* extract src, dest address */
	hend = (caddr_t)clnp + clnp->cnf_hdr_len;
	hoff = (caddr_t)clnp + sizeof(struct clnp_fixed);
	CLNP_EXTRACT_ADDR(dst, hoff, hend);
	if (hoff == (caddr_t)0) {
		goto bad;
	}
	CLNP_EXTRACT_ADDR(src, hoff, hend);
	if (hoff == (caddr_t)0) {
		goto bad;
	}
	
	/*
	 *	Do not send ER if we generated the packet.
	 */
	if (clnp_ours(&src))
		goto bad;

	/* 
	 *	Trim mbuf to hold only the header.
	 *	This mbuf will be the 'data' of the er pdu
	 */
	if (m->m_next != NULL) {
		m_freem(m->m_next);
		m->m_next = NULL;
	}

	if (m->m_len > clnp->cnf_hdr_len)
		m_adj(m, (int)-(m->m_len - (int)clnp->cnf_hdr_len));

	/* route er pdu: note we send pkt to src of original packet  */
	if (clnp_route(&src, &route, /* flags */0, &first_hop, &ia) != 0)
		goto bad;

	/* compute our address based upon firsthop/ifp */
	if (ia)
			our_addr = &ia->ia_addr.siso_addr;
	else
			goto bad;
	ifp = ia->ia_ifp;

	IFDEBUG(D_DISCARD)
		printf("clnp_emit_er: to %s", clnp_iso_addrp(&src));
		printf(" from %s\n", clnp_iso_addrp(our_addr));
	ENDDEBUG

	IFDEBUG(D_DISCARD)
		printf("clnp_emit_er: packet routed to %s\n", 
			clnp_iso_addrp(&((struct sockaddr_iso *)first_hop)->siso_addr));
	ENDDEBUG

	/* allocate mbuf for er pdu header: punt on no space */
	MGET(m0, M_DONTWAIT, MT_HEADER);
	if (m0 == 0)
		goto bad;
	
	m0->m_next = m;
	er = mtod(m0, struct clnp_fixed *);
	*er = er_template;

	/* setup src/dst on er pdu */
	/* NOTE REVERSAL OF SRC/DST */
	hoff = (caddr_t)er + sizeof(struct clnp_fixed);
	CLNP_INSERT_ADDR(hoff, src);
	CLNP_INSERT_ADDR(hoff, *our_addr);

	/*
	 *	TODO: if complete src rt was specified, then reverse path, and
	 *	copy into er as option.
	 */

	/* add er option */
	*hoff++ = CLNPOVAL_ERREAS;	/* code */
	*hoff++ = 2;				/* length */
	*hoff++ = reason;			/* discard reason */
	*hoff++ = 0;				/* error localization = not specified */

	/* set length */
	er->cnf_hdr_len = m0->m_len = (u_char)(hoff - (caddr_t)er);
	total_len = m0->m_len + m->m_len;
	HTOC(er->cnf_seglen_msb, er->cnf_seglen_lsb, total_len);

	/* compute checksum (on header only) */
	iso_gen_csum(m0, CLNP_CKSUM_OFF, (int)er->cnf_hdr_len);

	/* trim packet if too large for interface */
	if (total_len > ifp->if_mtu)
		m_adj(m0, -(total_len - ifp->if_mtu));
	
	/* send packet */
	INCSTAT(cns_er_outhist[clnp_er_index(reason)]);
	(void) (*ifp->if_output)(ifp, m0, first_hop, route.ro_rt);
	goto done;

bad:
	m_freem(m);

done:
	/* free route if it is a temp */
	if (route.ro_rt != NULL)
		RTFREE(route.ro_rt);
}

clnp_er_index(p)
u_char p;
{
	register u_char *cp = clnp_er_codes + CLNP_ERRORS;
	while (cp > clnp_er_codes) {
		cp--;
		if (*cp == p)
			return (cp - clnp_er_codes);
	}
	return (CLNP_ERRORS + 1);
}
Commit	Line	Data
7bcd1bb8 KB	1	/*-
	2	* Copyright (c) 1991 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* %sccs.include.redist.c%
	6	*
5548a02f	7	* @(#)clnp_er.c 7.8 (Berkeley) %G%
7bcd1bb8 KB	8	*/
7bcd1bb8 KB	9
011444fe KS	10	/***********************************************************
	11	Copyright IBM Corporation 1987
	12
	13	All Rights Reserved
	14
	15	Permission to use, copy, modify, and distribute this software and its
	16	documentation for any purpose and without fee is hereby granted,
	17	provided that the above copyright notice appear in all copies and that
	18	both that copyright notice and this permission notice appear in
	19	supporting documentation, and that the name of IBM not be
	20	used in advertising or publicity pertaining to distribution of the
	21	software without specific, written prior permission.
	22
	23	IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
	24	ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
	25	IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
	26	ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	27	WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
	28	ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
	29	SOFTWARE.
	30
	31	******************************************************************/
	32
	33	/*
	34	* ARGO Project, Computer Sciences Dept., University of Wisconsin - Madison
	35	*/
69ee739d KS	36	/* $Header: /var/src/sys/netiso/RCS/clnp_er.c,v 5.1 89/02/09 16:20:18 hagens Exp $ */
69ee739d KS	37	/* $Source: /var/src/sys/netiso/RCS/clnp_er.c,v $ */
011444fe	38
5548a02f KB	39	#include <sys/param.h>
	40	#include <sys/mbuf.h>
	41	#include <sys/domain.h>
	42	#include <sys/protosw.h>
	43	#include <sys/socket.h>
	44	#include <sys/socketvar.h>
	45	#include <sys/errno.h>
011444fe	46
5548a02f KB	47	#include <net/if.h>
5548a02f KB	48	#include <net/route.h>
011444fe	49
5548a02f KB	50	#include <netiso/iso.h>
	51	#include <netiso/iso_var.h>
	52	#include <netiso/iso_pcb.h>
4f565be6	53	#define CLNP_ER_CODES
5548a02f KB	54	#include <netiso/clnp.h>
	55	#include <netiso/clnp_stat.h>
	56	#include <netiso/argo_debug.h>
011444fe KS	57
	58	static struct clnp_fixed er_template = {
	59	ISO8473_CLNP, /* network identifier */
	60	0, /* length */
	61	ISO8473_V1, /* version */
	62	CLNP_TTL, /* ttl */
011444fe	63	CLNP_ER, /* type */
011444fe KS	64	0, /* segment length */
	65	0 /* checksum */
	66	};
	67
	68	/*
	69	* FUNCTION: clnp_er_input
	70	*
	71	* PURPOSE: Process an ER pdu.
	72	*
	73	* RETURNS:
	74	*
	75	* SIDE EFFECTS:
	76	*
	77	* NOTES:
	78	*/
	79	clnp_er_input(m, src, reason)
	80	struct mbuf m; / ptr to packet itself */
	81	struct iso_addr src; / ptr to src of er */
a50e2bc0	82	u_char reason; /* reason code of er */
011444fe KS	83	{
	84	int cmd = -1;
	85	extern u_char clnp_protox[];
	86
	87	IFDEBUG(D_CTLINPUT)
	88	printf("clnp_er_input: m x%x, src %s, reason x%x\n", m,
	89	clnp_iso_addrp(src), reason);
	90	ENDDEBUG
	91
4f565be6	92	INCSTAT(cns_er_inhist[clnp_er_index(reason)]);
011444fe KS	93	switch (reason) {
	94	case GEN_NOREAS:
	95	case GEN_PROTOERR:
011444fe KS	96	break;
	97	case GEN_BADCSUM:
	98	cmd = PRC_PARAMPROB;
011444fe KS	99	break;
	100	case GEN_CONGEST:
	101	cmd = PRC_QUENCH;
011444fe KS	102	break;
	103	case GEN_HDRSYNTAX:
	104	cmd = PRC_PARAMPROB;
011444fe KS	105	break;
011444fe KS	106	case GEN_SEGNEEDED:
addac7c3	107	cmd = PRC_MSGSIZE;
011444fe KS	108	break;
	109	case GEN_INCOMPLETE:
	110	cmd = PRC_PARAMPROB;
011444fe KS	111	break;
	112	case GEN_DUPOPT:
	113	cmd = PRC_PARAMPROB;
011444fe KS	114	break;
	115	case ADDR_DESTUNREACH:
	116	cmd = PRC_UNREACH_HOST;
011444fe KS	117	break;
	118	case ADDR_DESTUNKNOWN:
	119	cmd = PRC_UNREACH_PROTOCOL;
011444fe KS	120	break;
	121	case SRCRT_UNSPECERR:
	122	case SRCRT_SYNTAX:
	123	case SRCRT_UNKNOWNADDR:
	124	case SRCRT_BADPATH:
	125	cmd = PRC_UNREACH_SRCFAIL;
011444fe KS	126	break;
	127	case TTL_EXPTRANSIT:
	128	cmd = PRC_TIMXCEED_INTRANS;
011444fe KS	129	break;
	130	case TTL_EXPREASS:
	131	cmd = PRC_TIMXCEED_REASS;
011444fe KS	132	break;
	133	case DISC_UNSUPPOPT:
	134	case DISC_UNSUPPVERS:
	135	case DISC_UNSUPPSECURE:
	136	case DISC_UNSUPPSRCRT:
	137	case DISC_UNSUPPRECRT:
	138	cmd = PRC_PARAMPROB;
011444fe KS	139	break;
	140	case REASS_INTERFERE:
	141	cmd = PRC_TIMXCEED_REASS;
011444fe KS	142	break;
	143	}
	144
69ee739d KS	145	/*
	146	* tpclnp_ctlinput1 is called directly so that we don't
	147	* have to build an iso_sockaddr out of src.
	148	*/
011444fe	149	if (cmd >= 0)
69ee739d	150	tpclnp_ctlinput1(cmd, src);
011444fe KS	151
	152	m_freem(m);
	153	}
	154
	155	/*
	156	* FUNCTION: clnp_discard
	157	*
	158	* PURPOSE: Discard a clnp datagram
	159	*
	160	* RETURNS: nothing
	161	*
	162	* SIDE EFFECTS: Will emit an ER pdu if possible
	163	*
	164	* NOTES: This code assumes that we have previously tried to pull
	165	* up the header of the datagram into one mbuf.
	166	*/
	167	clnp_discard(m, reason)
	168	struct mbuf m; / header of packet to discard */
	169	char reason; /* reason for discard */
	170	{
	171	IFDEBUG(D_DISCARD)
	172	printf("clnp_discard: m x%x, reason x%x\n", m, reason);
	173	ENDDEBUG
	174
	175	if (m != NULL) {
	176	if (m->m_len >= sizeof(struct clnp_fixed)) {
	177	register struct clnp_fixed clnp = mtod(m, struct clnp_fixed );
	178
a50e2bc0 KS	179	if (((clnp->cnf_type & CNF_TYPE) != CLNP_ER) &&
	180	(clnp->cnf_type & CNF_ERR_OK)) {
	181	clnp_emit_er(m, reason);
	182	return;
011444fe KS	183	}
	184	}
	185	m_freem(m);
	186	}
	187	}
	188
	189	/*
	190	* FUNCTION: clnp_emit_er
	191	*
	192	* PURPOSE: Send an ER pdu.
	193	* The src of the of the ER pdu is the host that is sending
	194	* the ER (ie. us), not the original destination of the
	195	* packet.
	196	*
	197	* RETURNS: nothing
	198	*
	199	* SIDE EFFECTS:
	200	*
	201	* NOTES: Takes responsibility for freeing mbuf passed
	202	* This function may be called with a packet that
	203	* was created by us; in this case, do not send
	204	* an ER.
	205	*/
	206	clnp_emit_er(m, reason)
	207	struct mbuf m; / header of packet to discard */
	208	char reason; /* reason for discard */
	209	{
	210	register struct clnp_fixed clnp = mtod(m, struct clnp_fixed );
	211	register struct clnp_fixed *er;
a50e2bc0	212	struct route_iso route;
011444fe KS	213	struct ifnet *ifp;
	214	struct sockaddr *first_hop;
	215	struct iso_addr src, dst, *our_addr;
	216	caddr_t hoff, hend;
	217	int total_len; /* total len of dg */
	218	struct mbuf m0; / contains er pdu hdr */
a50e2bc0	219	struct iso_ifaddr *ia = 0;
011444fe KS	220
	221	IFDEBUG(D_DISCARD)
	222	printf("clnp_emit_er: m x%x, hdr len %d\n", m, clnp->cnf_hdr_len);
	223	ENDDEBUG
	224
	225	bzero((caddr_t)&route, sizeof(route));
	226
	227	/*
	228	* If header length is incorrect, or entire header is not contained
	229	* in this mbuf, we punt
	230	*/
	231	if ((clnp->cnf_hdr_len < CLNP_HDR_MIN) \|\|
	232	(clnp->cnf_hdr_len > CLNP_HDR_MAX) \|\|
	233	(clnp->cnf_hdr_len > m->m_len))
	234	goto bad;
	235
	236	/* extract src, dest address */
	237	hend = (caddr_t)clnp + clnp->cnf_hdr_len;
	238	hoff = (caddr_t)clnp + sizeof(struct clnp_fixed);
	239	CLNP_EXTRACT_ADDR(dst, hoff, hend);
	240	if (hoff == (caddr_t)0) {
	241	goto bad;
	242	}
	243	CLNP_EXTRACT_ADDR(src, hoff, hend);
	244	if (hoff == (caddr_t)0) {
	245	goto bad;
	246	}
	247
	248	/*
	249	* Do not send ER if we generated the packet.
	250	*/
	251	if (clnp_ours(&src))
	252	goto bad;
	253
	254	/*
	255	* Trim mbuf to hold only the header.
	256	* This mbuf will be the 'data' of the er pdu
	257	*/
	258	if (m->m_next != NULL) {
	259	m_freem(m->m_next);
	260	m->m_next = NULL;
	261	}
	262
	263	if (m->m_len > clnp->cnf_hdr_len)
a50e2bc0	264	m_adj(m, (int)-(m->m_len - (int)clnp->cnf_hdr_len));
011444fe KS	265
011444fe KS	266	/* route er pdu: note we send pkt to src of original packet */
a50e2bc0	267	if (clnp_route(&src, &route, /* flags */0, &first_hop, &ia) != 0)
011444fe KS	268	goto bad;
	269
	270	/* compute our address based upon firsthop/ifp */
a50e2bc0 KS	271	if (ia)
	272	our_addr = &ia->ia_addr.siso_addr;
	273	else
	274	goto bad;
	275	ifp = ia->ia_ifp;
011444fe KS	276
	277	IFDEBUG(D_DISCARD)
	278	printf("clnp_emit_er: to %s", clnp_iso_addrp(&src));
	279	printf(" from %s\n", clnp_iso_addrp(our_addr));
	280	ENDDEBUG
	281
	282	IFDEBUG(D_DISCARD)
	283	printf("clnp_emit_er: packet routed to %s\n",
	284	clnp_iso_addrp(&((struct sockaddr_iso *)first_hop)->siso_addr));
	285	ENDDEBUG
	286
	287	/* allocate mbuf for er pdu header: punt on no space */
	288	MGET(m0, M_DONTWAIT, MT_HEADER);
	289	if (m0 == 0)
	290	goto bad;
	291
	292	m0->m_next = m;
	293	er = mtod(m0, struct clnp_fixed *);
	294	*er = er_template;
	295
	296	/* setup src/dst on er pdu */
	297	/* NOTE REVERSAL OF SRC/DST */
	298	hoff = (caddr_t)er + sizeof(struct clnp_fixed);
a50e2bc0 KS	299	CLNP_INSERT_ADDR(hoff, src);
a50e2bc0 KS	300	CLNP_INSERT_ADDR(hoff, *our_addr);
011444fe KS	301
	302	/*
	303	* TODO: if complete src rt was specified, then reverse path, and
	304	* copy into er as option.
	305	*/
	306
	307	/* add er option */
	308	hoff++ = CLNPOVAL_ERREAS; / code */
	309	hoff++ = 2; / length */
	310	hoff++ = reason; / discard reason */
	311	hoff++ = 0; / error localization = not specified */
	312
	313	/* set length */
	314	er->cnf_hdr_len = m0->m_len = (u_char)(hoff - (caddr_t)er);
	315	total_len = m0->m_len + m->m_len;
	316	HTOC(er->cnf_seglen_msb, er->cnf_seglen_lsb, total_len);
	317
	318	/* compute checksum (on header only) */
	319	iso_gen_csum(m0, CLNP_CKSUM_OFF, (int)er->cnf_hdr_len);
	320
	321	/* trim packet if too large for interface */
	322	if (total_len > ifp->if_mtu)
	323	m_adj(m0, -(total_len - ifp->if_mtu));
	324
	325	/* send packet */
4f565be6	326	INCSTAT(cns_er_outhist[clnp_er_index(reason)]);
addac7c3	327	(void) (*ifp->if_output)(ifp, m0, first_hop, route.ro_rt);
011444fe KS	328	goto done;
	329
	330	bad:
	331	m_freem(m);
	332
	333	done:
	334	/* free route if it is a temp */
	335	if (route.ro_rt != NULL)
	336	RTFREE(route.ro_rt);
	337	}
4f565be6 KS	338
	339	clnp_er_index(p)
	340	u_char p;
	341	{
	342	register u_char *cp = clnp_er_codes + CLNP_ERRORS;
	343	while (cp > clnp_er_codes) {
	344	cp--;
	345	if (*cp == p)
	346	return (cp - clnp_er_codes);
	347	}
	348	return (CLNP_ERRORS + 1);
	349	}