[unix-history] / usr / src / sys / netns / ns_input.c

/*
 * Copyright (c) 1982 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	@(#)ns_input.c	6.10 (Berkeley) %G%
 */

#include "param.h"
#include "systm.h"
#include "mbuf.h"
#include "domain.h"
#include "protosw.h"
#include "socket.h"
#include "socketvar.h"
#include "errno.h"
#include "time.h"
#include "kernel.h"

#include "../net/if.h"
#include "../net/route.h"
#include "../net/raw_cb.h"

#include "ns.h"
#include "ns_if.h"
#include "ns_pcb.h"
#include "idp.h"
#include "idp_var.h"
#include "ns_error.h"

/*
 * NS initialization.
 */
union ns_host	ns_thishost;
union ns_host	ns_zerohost;
union ns_host	ns_broadhost;

static char allones[] = {-1, -1, -1, -1, -1, -1};

struct nspcb nspcb;
struct nspcb nsrawpcb;

struct ifqueue	nsintrq;
int	nsqmaxlen = IFQ_MAXLEN;

int	idpcksum = 1;
long	ns_pexseq;

ns_init()
{
	extern struct timeval time;

	ns_broadhost = * (union ns_host *) allones;
	nspcb.nsp_next = nspcb.nsp_prev = &nspcb;
	nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb;
	nsintrq.ifq_maxlen = nsqmaxlen;
	ns_pexseq = time.tv_usec;
}

/*
 * Idp input routine.  Pass to next level.
 */
int nsintr_getpck = 0;
int nsintr_swtch = 0;
nsintr()
{
	register struct idp *idp;
	register struct mbuf *m;
	register struct nspcb *nsp;
	struct ifnet *ifp;
	struct mbuf *m0;
	register int i;
	int len, s, error;
	char oddpacketp;

next:
	/*
	 * Get next datagram off input queue and get IDP header
	 * in first mbuf.
	 */
	s = splimp();
	IF_DEQUEUEIF(&nsintrq, m, ifp);
	splx(s);
	nsintr_getpck++;
	if (m == 0)
		return;
	if ((m->m_off > MMAXOFF || m->m_len < sizeof (struct idp)) &&
	    (m = m_pullup(m, sizeof (struct idp))) == 0) {
		idpstat.idps_toosmall++;
		goto next;
	}

	/*
	 * Give any raw listeners a crack at the packet
	 */
	for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
		struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
		if (m1) idp_input(m1, nsp, ifp);
	}

	idp = mtod(m, struct idp *);
	len = ntohs(idp->idp_len);
	if (oddpacketp = len & 1) {
		len++;		/* If this packet is of odd length,
				   preserve garbage byte for checksum */
	}

	/*
	 * Check that the amount of data in the buffers
	 * is as at least much as the IDP header would have us expect.
	 * Trim mbufs if longer than we expect.
	 * Drop packet if shorter than we expect.
	 */
	i = -len;
	m0 = m;
	for (;;) {
		i += m->m_len;
		if (m->m_next == 0)
			break;
		m = m->m_next;
	}
	if (i != 0) {
		if (i < 0) {
			idpstat.idps_tooshort++;
			m = m0;
			goto bad;
		}
		if (i <= m->m_len)
			m->m_len -= i;
		else
			m_adj(m0, -i);
	}
	m = m0;
	if (idpcksum && ((i = idp->idp_sum)!=0xffff)) {
		idp->idp_sum = 0;
		if (i != (idp->idp_sum = ns_cksum(m,len))) {
			idpstat.idps_badsum++;
			idp->idp_sum = i;
			if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host))
				error = NS_ERR_BADSUM;
			else
				error = NS_ERR_BADSUM_T;
			ns_error(m, error, 0);
			goto next;
		}
	}
	/*
	 * Is this a directed broadcast?
	 */
	if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) {
		if ((ns_netof(idp->idp_dna)!=ns_netof(idp->idp_sna)) &&
		   (ns_netof(idp->idp_dna)!=-1) && (ns_netof(idp->idp_sna)!=0)
		   && (ns_netof(idp->idp_dna)!=0)) {
			/*
			 * Look to see if I need to eat this packet.
			 * Algorithm is to forward all young packets
			 * and prematurely age any packets which will
			 * by physically broadcasted.
			 * Any very old packets eaten without forwarding
			 * would die anyway.
			 *
			 * Suggestion of Bill Nesheim, Cornell U.
			 */
			if (idp->idp_tc < NS_MAXHOPS) {
				idp_forward(idp);
				goto next;
			}
		}
	/*
	 * Is this our packet? If not, forward.
	 */
	} else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) {
		idp_forward(idp);
		goto next;
	}
	/*
	 * Locate pcb for datagram.
	 */
	nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD);
	/*
	 * Switch out to protocol's input routine.
	 */
	nsintr_swtch++;
	if (nsp) {
		if (oddpacketp) {
			m_adj(m0, -1);
		}
		if ((nsp->nsp_flags & NSP_ALL_PACKETS)==0)
			switch (idp->idp_pt) {

			    case NSPROTO_SPP:
				    spp_input(m, nsp, ifp);
				    goto next;

			    case NSPROTO_ERROR:
				    ns_err_input(m);
				    goto next;
			}
		idp_input(m, nsp, ifp);
	} else {
		ns_error(m, NS_ERR_NOSOCK, 0);
	}
	goto next;

bad:
	m_freem(m);
	goto next;
}

u_char nsctlerrmap[PRC_NCMDS] = {
	ECONNABORTED,	ECONNABORTED,	0,		0,
	0,		0,		EHOSTDOWN,	EHOSTUNREACH,
	ENETUNREACH,	EHOSTUNREACH,	ECONNREFUSED,	ECONNREFUSED,
	EMSGSIZE,	0,		0,		0,
	0,		0,		0,		0
};

idp_donosocks = 1;

idp_ctlinput(cmd, arg)
	int cmd;
	caddr_t arg;
{
	struct ns_addr *ns;
	struct nspcb *nsp;
	struct ns_errp *errp;
	int idp_abort();
	extern struct nspcb *idp_drop();
	int type;

	if (cmd < 0 || cmd > PRC_NCMDS)
		return;
	if (nsctlerrmap[cmd] == 0)
		return;		/* XXX */
	type = NS_ERR_UNREACH_HOST;
	switch (cmd) {
		struct sockaddr_ns *sns;

	case PRC_IFDOWN:
	case PRC_HOSTDEAD:
	case PRC_HOSTUNREACH:
		sns = (struct sockaddr_ns *)arg;
		if (sns->sns_family != AF_INET)
			return;
		ns = &sns->sns_addr;
		break;

	default:
		errp = (struct ns_errp *)arg;
		ns = &errp->ns_err_idp.idp_dna;
		type = errp->ns_err_num;
		type = ntohs((u_short)type);
	}
	switch (type) {

	case NS_ERR_UNREACH_HOST:
		ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, (long)0);
		break;

	case NS_ERR_NOSOCK:
		nsp = ns_pcblookup(ns, errp->ns_err_idp.idp_sna.x_port,
			NS_WILDCARD);
		if(nsp && idp_donosocks && ! ns_nullhost(nsp->nsp_faddr))
			(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
	}
}

int	idpprintfs = 0;
int	idpforwarding = 1;
/*
 * Forward a packet.  If some error occurs return the sender
 * an error packet.  Note we can't always generate a meaningful
 * error message because the NS errors don't have a large enough repetoire
 * of codes and types.
 */
struct route idp_droute;
struct route idp_sroute;

idp_forward(idp)
	register struct idp *idp;
{
	register int error, type, code;
	struct mbuf *mcopy = NULL;
	int agedelta = 1;
	int flags = NS_FORWARDING;
	int ok_there = 0;
	int ok_back = 0;

	if (idpprintfs) {
		printf("forward: src ");
		ns_printhost(&idp->idp_sna);
		printf(", dst ");
		ns_printhost(&idp->idp_dna);
		printf("hop count %d\n", idp->idp_tc);
	}
	if (idpforwarding == 0) {
		/* can't tell difference between net and host */
		type = NS_ERR_UNREACH_HOST, code = 0;
		goto senderror;
	}
	idp->idp_tc++;
	if (idp->idp_tc > NS_MAXHOPS) {
		type = NS_ERR_TOO_OLD, code = 0;
		goto senderror;
	}
	/*
	 * Save at most 42 bytes of the packet in case
	 * we need to generate an NS error message to the src.
	 */
	mcopy = m_copy(dtom(idp), 0, imin(ntohs(idp->idp_len), 42));

	if ((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) {
		type = NS_ERR_UNREACH_HOST, code = 0;
		goto senderror;
	}
	/*
	 * Here we think about  forwarding  broadcast packets,
	 * so we try to insure that it doesn't go back out
	 * on the interface it came in on.  Also, if we
	 * are going to physically broadcast this, let us
	 * age the packet so we can eat it safely the second time around.
	 */
	if (idp->idp_dna.x_host.c_host[0] & 0x1) {
		struct ns_ifaddr *ia = ns_iaonnetof(idp->idp_dna.x_net);
		struct ifnet *ifp;
		if (ia) {
			/* I'm gonna hafta eat this packet */
			agedelta += NS_MAXHOPS - idp->idp_tc;
			idp->idp_tc = NS_MAXHOPS;
		}
		if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) {
			/* error = ENETUNREACH; He'll never get it! */
			m_freem(dtom(idp));
			goto cleanup;
		}
		if (idp_droute.ro_rt &&
		    (ifp=idp_droute.ro_rt->rt_ifp) &&
		    idp_sroute.ro_rt &&
		    (ifp!=idp_sroute.ro_rt->rt_ifp)) {
			flags |= NS_ALLOWBROADCAST;
		} else {
			type = NS_ERR_UNREACH_HOST, code = 0;
			goto senderror;
		}
	}
	/* need to adjust checksum */
	if (idp->idp_sum!=0xffff) {
		union bytes {
			u_char c[4];
			u_short s[2];
			long l;
		} x;
		register int shift;
		x.l = 0; x.c[0] = agedelta;
		shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf;
		x.l = idp->idp_sum + (x.l << shift);
		x.l = x.s[0] + x.s[1];
		x.l = x.s[0] + x.s[1];
		if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l;
	}
	if ((error = ns_output(dtom(idp), &idp_droute, flags)) && 
	    (mcopy!=NULL)) {
		idp = mtod(mcopy, struct idp *);
		type = NS_ERR_UNSPEC_T, code = 0;
		switch (error) {

		case ENETUNREACH:
		case EHOSTDOWN:
		case EHOSTUNREACH:
		case ENETDOWN:
		case EPERM:
			type = NS_ERR_UNREACH_HOST;
			break;

		case EMSGSIZE:
			type = NS_ERR_TOO_BIG;
			code = 576; /* too hard to figure out mtu here */
			break;

		case ENOBUFS:
			type = NS_ERR_UNSPEC_T;
			break;
		}
		mcopy = NULL;
	senderror:
		ns_error(dtom(idp), type, code);
	}
cleanup:
	if (ok_there)
		idp_undo_route(&idp_droute);
	if (ok_back)
		idp_undo_route(&idp_sroute);
	if (mcopy != NULL)
		m_freem(mcopy);
}

idp_do_route(src, ro)
struct ns_addr *src;
struct route *ro;
{
	
	struct sockaddr_ns *dst;

	bzero((caddr_t)ro, sizeof (*ro));
	dst = (struct sockaddr_ns *)&ro->ro_dst;

	dst->sns_family = AF_NS;
	dst->sns_addr = *src;
	dst->sns_addr.x_port = 0;
	rtalloc(ro);
	if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) {
		return (0);
	}
	ro->ro_rt->rt_use++;
	return (1);
}

idp_undo_route(ro)
register struct route *ro;
{
	if (ro->ro_rt) {RTFREE(ro->ro_rt);}
}
ns_watch_output(m)
struct mbuf *m;
{
	register struct nspcb *nsp;
	/*
	 * Give any raw listeners a crack at the packet
	 */
	for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
		struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
		if (m1) idp_input(m1, nsp);
	}
}
Commit	Line	Data
8ae0e4b4 KM	1	/*
	2	* Copyright (c) 1982 Regents of the University of California.
	3	* All rights reserved. The Berkeley software License Agreement
	4	* specifies the terms and conditions for redistribution.
	5	*
d2ec0713	6	* @(#)ns_input.c 6.10 (Berkeley) %G%
8ae0e4b4	7	*/
bbcda6f4 KS	8
	9	#include "param.h"
	10	#include "systm.h"
	11	#include "mbuf.h"
	12	#include "domain.h"
	13	#include "protosw.h"
	14	#include "socket.h"
	15	#include "socketvar.h"
	16	#include "errno.h"
	17	#include "time.h"
	18	#include "kernel.h"
	19
	20	#include "../net/if.h"
	21	#include "../net/route.h"
	22	#include "../net/raw_cb.h"
	23
	24	#include "ns.h"
	25	#include "ns_if.h"
	26	#include "ns_pcb.h"
	27	#include "idp.h"
	28	#include "idp_var.h"
	29	#include "ns_error.h"
	30
	31	/*
	32	* NS initialization.
	33	*/
	34	union ns_host ns_thishost;
	35	union ns_host ns_zerohost;
	36	union ns_host ns_broadhost;
	37
	38	static char allones[] = {-1, -1, -1, -1, -1, -1};
	39
	40	struct nspcb nspcb;
	41	struct nspcb nsrawpcb;
	42
	43	struct ifqueue nsintrq;
	44	int nsqmaxlen = IFQ_MAXLEN;
	45
350dbdec	46	int idpcksum = 1;
623533cc	47	long ns_pexseq;
bbcda6f4 KS	48
	49	ns_init()
	50	{
623533cc KS	51	extern struct timeval time;
623533cc KS	52
bbcda6f4 KS	53	ns_broadhost = * (union ns_host *) allones;
	54	nspcb.nsp_next = nspcb.nsp_prev = &nspcb;
	55	nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb;
	56	nsintrq.ifq_maxlen = nsqmaxlen;
623533cc	57	ns_pexseq = time.tv_usec;
bbcda6f4 KS	58	}
	59
	60	/*
	61	* Idp input routine. Pass to next level.
	62	*/
	63	int nsintr_getpck = 0;
	64	int nsintr_swtch = 0;
	65	nsintr()
	66	{
	67	register struct idp *idp;
	68	register struct mbuf *m;
19d8bb77	69	register struct nspcb *nsp;
47685d3d	70	struct ifnet *ifp;
bbcda6f4 KS	71	struct mbuf *m0;
	72	register int i;
	73	int len, s, error;
	74	char oddpacketp;
	75
	76	next:
	77	/*
	78	* Get next datagram off input queue and get IDP header
	79	* in first mbuf.
	80	*/
	81	s = splimp();
47685d3d	82	IF_DEQUEUEIF(&nsintrq, m, ifp);
bbcda6f4 KS	83	splx(s);
	84	nsintr_getpck++;
	85	if (m == 0)
	86	return;
	87	if ((m->m_off > MMAXOFF \|\| m->m_len < sizeof (struct idp)) &&
	88	(m = m_pullup(m, sizeof (struct idp))) == 0) {
	89	idpstat.idps_toosmall++;
	90	goto next;
	91	}
	92
	93	/*
	94	* Give any raw listeners a crack at the packet
	95	*/
	96	for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
f97be0c9	97	struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
d2ec0713	98	if (m1) idp_input(m1, nsp, ifp);
bbcda6f4 KS	99	}
	100
	101	idp = mtod(m, struct idp *);
	102	len = ntohs(idp->idp_len);
	103	if (oddpacketp = len & 1) {
	104	len++; /* If this packet is of odd length,
	105	preserve garbage byte for checksum */
	106	}
	107
	108	/*
	109	* Check that the amount of data in the buffers
	110	* is as at least much as the IDP header would have us expect.
	111	* Trim mbufs if longer than we expect.
	112	* Drop packet if shorter than we expect.
	113	*/
	114	i = -len;
	115	m0 = m;
	116	for (;;) {
	117	i += m->m_len;
	118	if (m->m_next == 0)
	119	break;
	120	m = m->m_next;
	121	}
	122	if (i != 0) {
	123	if (i < 0) {
	124	idpstat.idps_tooshort++;
	125	m = m0;
	126	goto bad;
	127	}
	128	if (i <= m->m_len)
	129	m->m_len -= i;
	130	else
	131	m_adj(m0, -i);
	132	}
	133	m = m0;
	134	if (idpcksum && ((i = idp->idp_sum)!=0xffff)) {
	135	idp->idp_sum = 0;
	136	if (i != (idp->idp_sum = ns_cksum(m,len))) {
	137	idpstat.idps_badsum++;
623533cc	138	idp->idp_sum = i;
bbcda6f4 KS	139	if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host))
	140	error = NS_ERR_BADSUM;
	141	else
	142	error = NS_ERR_BADSUM_T;
	143	ns_error(m, error, 0);
	144	goto next;
	145	}
	146	}
	147	/*
	148	* Is this a directed broadcast?
	149	*/
	150	if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) {
	151	if ((ns_netof(idp->idp_dna)!=ns_netof(idp->idp_sna)) &&
	152	(ns_netof(idp->idp_dna)!=-1) && (ns_netof(idp->idp_sna)!=0)
	153	&& (ns_netof(idp->idp_dna)!=0)) {
	154	/*
c7ea7bd3 KS	155	* Look to see if I need to eat this packet.
	156	* Algorithm is to forward all young packets
	157	* and prematurely age any packets which will
	158	* by physically broadcasted.
	159	* Any very old packets eaten without forwarding
	160	* would die anyway.
	161	*
	162	* Suggestion of Bill Nesheim, Cornell U.
bbcda6f4	163	*/
350dbdec	164	if (idp->idp_tc < NS_MAXHOPS) {
c7ea7bd3	165	idp_forward(idp);
bbcda6f4	166	goto next;
c7ea7bd3	167	}
bbcda6f4 KS	168	}
	169	/*
	170	* Is this our packet? If not, forward.
	171	*/
	172	} else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) {
	173	idp_forward(idp);
	174	goto next;
	175	}
19d8bb77 KS	176	/*
	177	* Locate pcb for datagram.
	178	*/
	179	nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD);
	180	/*
	181	* Switch out to protocol's input routine.
	182	*/
	183	nsintr_swtch++;
	184	if (nsp) {
	185	if (oddpacketp) {
	186	m_adj(m0, -1);
	187	}
	188	if ((nsp->nsp_flags & NSP_ALL_PACKETS)==0)
	189	switch (idp->idp_pt) {
350dbdec	190
19d8bb77	191	case NSPROTO_SPP:
d2ec0713	192	spp_input(m, nsp, ifp);
19d8bb77	193	goto next;
350dbdec	194
19d8bb77 KS	195	case NSPROTO_ERROR:
	196	ns_err_input(m);
	197	goto next;
	198	}
d2ec0713	199	idp_input(m, nsp, ifp);
19d8bb77 KS	200	} else {
19d8bb77 KS	201	ns_error(m, NS_ERR_NOSOCK, 0);
bbcda6f4 KS	202	}
	203	goto next;
	204
	205	bad:
	206	m_freem(m);
	207	goto next;
	208	}
	209
	210	u_char nsctlerrmap[PRC_NCMDS] = {
	211	ECONNABORTED, ECONNABORTED, 0, 0,
	212	0, 0, EHOSTDOWN, EHOSTUNREACH,
	213	ENETUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
	214	EMSGSIZE, 0, 0, 0,
	215	0, 0, 0, 0
	216	};
	217
623533cc KS	218	idp_donosocks = 1;
623533cc KS	219
bbcda6f4 KS	220	idp_ctlinput(cmd, arg)
	221	int cmd;
	222	caddr_t arg;
	223	{
	224	struct ns_addr *ns;
623533cc KS	225	struct nspcb *nsp;
623533cc KS	226	struct ns_errp *errp;
bbcda6f4	227	int idp_abort();
f97be0c9	228	extern struct nspcb *idp_drop();
bbcda6f4 KS	229	int type;
	230
	231	if (cmd < 0 \|\| cmd > PRC_NCMDS)
	232	return;
	233	if (nsctlerrmap[cmd] == 0)
	234	return; /* XXX */
	235	type = NS_ERR_UNREACH_HOST;
d2ec0713 KS	236	switch (cmd) {
	237	struct sockaddr_ns *sns;
	238
	239	case PRC_IFDOWN:
	240	case PRC_HOSTDEAD:
	241	case PRC_HOSTUNREACH:
	242	sns = (struct sockaddr_ns *)arg;
	243	if (sns->sns_family != AF_INET)
	244	return;
	245	ns = &sns->sns_addr;
	246	break;
	247
	248	default:
623533cc KS	249	errp = (struct ns_errp *)arg;
	250	ns = &errp->ns_err_idp.idp_dna;
	251	type = errp->ns_err_num;
f97be0c9	252	type = ntohs((u_short)type);
bbcda6f4 KS	253	}
bbcda6f4 KS	254	switch (type) {
350dbdec	255
bbcda6f4	256	case NS_ERR_UNREACH_HOST:
f97be0c9	257	ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, (long)0);
623533cc KS	258	break;
	259
	260	case NS_ERR_NOSOCK:
	261	nsp = ns_pcblookup(ns, errp->ns_err_idp.idp_sna.x_port,
	262	NS_WILDCARD);
	263	if(nsp && idp_donosocks && ! ns_nullhost(nsp->nsp_faddr))
f97be0c9	264	(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
bbcda6f4 KS	265	}
	266	}
	267
	268	int idpprintfs = 0;
	269	int idpforwarding = 1;
	270	/*
	271	* Forward a packet. If some error occurs return the sender
	272	* an error packet. Note we can't always generate a meaningful
	273	* error message because the NS errors don't have a large enough repetoire
	274	* of codes and types.
	275	*/
	276	struct route idp_droute;
	277	struct route idp_sroute;
	278
	279	idp_forward(idp)
	280	register struct idp *idp;
	281	{
	282	register int error, type, code;
c7ea7bd3 KS	283	struct mbuf *mcopy = NULL;
	284	int agedelta = 1;
	285	int flags = NS_FORWARDING;
	286	int ok_there = 0;
	287	int ok_back = 0;
bbcda6f4 KS	288
	289	if (idpprintfs) {
	290	printf("forward: src ");
	291	ns_printhost(&idp->idp_sna);
	292	printf(", dst ");
	293	ns_printhost(&idp->idp_dna);
	294	printf("hop count %d\n", idp->idp_tc);
	295	}
	296	if (idpforwarding == 0) {
	297	/* can't tell difference between net and host */
	298	type = NS_ERR_UNREACH_HOST, code = 0;
	299	goto senderror;
	300	}
	301	idp->idp_tc++;
	302	if (idp->idp_tc > NS_MAXHOPS) {
	303	type = NS_ERR_TOO_OLD, code = 0;
	304	goto senderror;
	305	}
c7ea7bd3 KS	306	/*
	307	* Save at most 42 bytes of the packet in case
	308	* we need to generate an NS error message to the src.
	309	*/
	310	mcopy = m_copy(dtom(idp), 0, imin(ntohs(idp->idp_len), 42));
	311
350dbdec	312	if ((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) {
c7ea7bd3 KS	313	type = NS_ERR_UNREACH_HOST, code = 0;
	314	goto senderror;
	315	}
	316	/*
	317	* Here we think about forwarding broadcast packets,
	318	* so we try to insure that it doesn't go back out
	319	* on the interface it came in on. Also, if we
	320	* are going to physically broadcast this, let us
	321	* age the packet so we can eat it safely the second time around.
	322	*/
	323	if (idp->idp_dna.x_host.c_host[0] & 0x1) {
	324	struct ns_ifaddr *ia = ns_iaonnetof(idp->idp_dna.x_net);
	325	struct ifnet *ifp;
	326	if (ia) {
	327	/* I'm gonna hafta eat this packet */
	328	agedelta += NS_MAXHOPS - idp->idp_tc;
	329	idp->idp_tc = NS_MAXHOPS;
	330	}
	331	if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) {
	332	/* error = ENETUNREACH; He'll never get it! */
	333	m_freem(dtom(idp));
	334	goto cleanup;
	335	}
	336	if (idp_droute.ro_rt &&
	337	(ifp=idp_droute.ro_rt->rt_ifp) &&
	338	idp_sroute.ro_rt &&
	339	(ifp!=idp_sroute.ro_rt->rt_ifp)) {
	340	flags \|= NS_ALLOWBROADCAST;
	341	} else {
	342	type = NS_ERR_UNREACH_HOST, code = 0;
	343	goto senderror;
	344	}
	345	}
bbcda6f4 KS	346	/* need to adjust checksum */
	347	if (idp->idp_sum!=0xffff) {
	348	union bytes {
	349	u_char c[4];
	350	u_short s[2];
	351	long l;
	352	} x;
	353	register int shift;
c7ea7bd3	354	x.l = 0; x.c[0] = agedelta;
bbcda6f4 KS	355	shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf;
	356	x.l = idp->idp_sum + (x.l << shift);
	357	x.l = x.s[0] + x.s[1];
	358	x.l = x.s[0] + x.s[1];
	359	if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l;
	360	}
c7ea7bd3 KS	361	if ((error = ns_output(dtom(idp), &idp_droute, flags)) &&
	362	(mcopy!=NULL)) {
	363	idp = mtod(mcopy, struct idp *);
	364	type = NS_ERR_UNSPEC_T, code = 0;
	365	switch (error) {
	366
	367	case ENETUNREACH:
	368	case EHOSTDOWN:
	369	case EHOSTUNREACH:
	370	case ENETDOWN:
	371	case EPERM:
	372	type = NS_ERR_UNREACH_HOST;
	373	break;
bbcda6f4	374
c7ea7bd3 KS	375	case EMSGSIZE:
	376	type = NS_ERR_TOO_BIG;
	377	code = 576; /* too hard to figure out mtu here */
	378	break;
bbcda6f4	379
c7ea7bd3 KS	380	case ENOBUFS:
	381	type = NS_ERR_UNSPEC_T;
	382	break;
bbcda6f4	383	}
0ff552c7 KS	384	mcopy = NULL;
	385	senderror:
	386	ns_error(dtom(idp), type, code);
bbcda6f4	387	}
c7ea7bd3 KS	388	cleanup:
	389	if (ok_there)
	390	idp_undo_route(&idp_droute);
	391	if (ok_back)
	392	idp_undo_route(&idp_sroute);
	393	if (mcopy != NULL)
	394	m_freem(mcopy);
bbcda6f4 KS	395	}
	396
	397	idp_do_route(src, ro)
	398	struct ns_addr *src;
	399	struct route *ro;
	400	{
	401
	402	struct sockaddr_ns *dst;
	403
	404	bzero((caddr_t)ro, sizeof (*ro));
	405	dst = (struct sockaddr_ns *)&ro->ro_dst;
	406
	407	dst->sns_family = AF_NS;
	408	dst->sns_addr = *src;
350dbdec	409	dst->sns_addr.x_port = 0;
bbcda6f4 KS	410	rtalloc(ro);
bbcda6f4 KS	411	if (ro->ro_rt == 0 \|\| ro->ro_rt->rt_ifp == 0) {
350dbdec	412	return (0);
bbcda6f4 KS	413	}
bbcda6f4 KS	414	ro->ro_rt->rt_use++;
350dbdec	415	return (1);
bbcda6f4 KS	416	}
	417
	418	idp_undo_route(ro)
	419	register struct route *ro;
	420	{
	421	if (ro->ro_rt) {RTFREE(ro->ro_rt);}
	422	}
	423	ns_watch_output(m)
	424	struct mbuf *m;
	425	{
	426	register struct nspcb *nsp;
	427	/*
	428	* Give any raw listeners a crack at the packet
	429	*/
	430	for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
f97be0c9	431	struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
bbcda6f4 KS	432	if (m1) idp_input(m1, nsp);
	433	}
	434	}