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source: rtems/cpukit/libnetworking/netinet/if_ether.c @ 39bad7e8

4.104.115

Last change on this file since 39bad7e8 was 404b1fb4, checked in by Ralf Corsepius <ralf.corsepius@…>, on 12/22/08 at 17:47:57
Add missing initializers.
Property mode set to `100644`
File size: 18.3 KB

Line
1	/*
2	* Copyright (c) 1982, 1986, 1988, 1993
3	* The Regents of the University of California. All rights reserved.
4	*
5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions
7	* are met:
8	* 1. Redistributions of source code must retain the above copyright
9	* notice, this list of conditions and the following disclaimer.
10	* 2. Redistributions in binary form must reproduce the above copyright
11	* notice, this list of conditions and the following disclaimer in the
12	* documentation and/or other materials provided with the distribution.
13	* 4. Neither the name of the University nor the names of its contributors
14	* may be used to endorse or promote products derived from this software
15	* without specific prior written permission.
16	*
17	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27	* SUCH DAMAGE.
28	*
29	* @(#)if_ether.c 8.1 (Berkeley) 6/10/93
30	* $FreeBSD: src/sys/netinet/if_ether.c,v 1.136 2005/03/13 11:23:22 glebius Exp $
31	*/
32
33	/*
34	* $Id$
35	*/
36
37	/*
38	* Ethernet address resolution protocol.
39	* TODO:
40	* add "inuse/lock" bit (or ref. count) along with valid bit
41	*/
42
43	#include "opt_inet.h"
44
45	#include <sys/param.h>
46	#include <sys/kernel.h>
47	#include <rtems/bsd/sys/queue.h>
48	#include <sys/sysctl.h>
49	#include <sys/systm.h>
50	#include <sys/mbuf.h>
51	#include <sys/malloc.h>
52	#include <sys/socket.h>
53	#include <sys/syslog.h>
54
55	#include <net/if.h>
56	#include <net/if_dl.h>
57	#include <net/if_types.h>
58	#include <net/route.h>
59	#include <net/netisr.h>
60
61	#include <netinet/in.h>
62	#include <netinet/in_var.h>
63	#include <netinet/if_ether.h>
64
65	#define SIN(s) ((struct sockaddr_in *)s)
66	#define SDL(s) ((struct sockaddr_dl *)s)
67
68	SYSCTL_DECL(_net_link_ether);
69	SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
70
71	/* timer values */
72	static int arpt_prune = (5601); /* walk list every 5 minutes */
73	static int arpt_keep = (2060); / once resolved, good for 20 more minutes */
74	static int arpt_down = 20; /* once declared down, don't send for 20 sec */
75
76	SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
77	&arpt_prune, 0, "");
78	SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
79	&arpt_keep, 0, "");
80	SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
81	&arpt_down, 0, "");
82
83	#define rt_expire rt_rmx.rmx_expire
84
85	struct llinfo_arp {
86	LIST_ENTRY(llinfo_arp) la_le;
87	struct rtentry *la_rt;
88	struct mbuf la_hold; / last packet until resolved/timeout */
89	long la_asked; /* last time we QUERIED for this addr */
90	#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */
91	};
92
93	static LIST_HEAD(, llinfo_arp) llinfo_arp;
94
95	struct ifqueue arpintrq = {0, 0, 0, 50, 0};
96	static int arp_inuse, arp_allocated;
97
98	static int arp_maxtries = 5;
99	static int useloopback = 1; /* use loopback interface for local traffic */
100	static int arp_proxyall = 0;
101
102	SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
103	&arp_maxtries, 0, "");
104	SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
105	&useloopback, 0, "");
106	SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
107	&arp_proxyall, 0, "");
108
109	static void arp_rtrequest(int, struct rtentry , struct sockaddr );
110	static void arprequest(struct arpcom , u_long , u_long , u_char );
111	void arpintr(void);
112	static void arptfree(struct llinfo_arp *);
113	static void arptimer(void *);
114	static struct llinfo_arp
115	*arplookup(u_long, int, int);
116	#ifdef INET
117	static void in_arpinput(struct mbuf *);
118	#endif
119
120	/*
121	* Timeout routine. Age arp_tab entries periodically.
122	*/
123	/* ARGSUSED */
124	static void
125	arptimer(void *ignored_arg)
126	{
127	int s = splnet();
128	struct llinfo_arp la, ola;
129
130	la = llinfo_arp.lh_first;
131	timeout(arptimer, (caddr_t)0, arpt_prune * hz);
132	while ((ola = la) != 0) {
133	register struct rtentry *rt = la->la_rt;
134	la = la->la_le.le_next;
135	if (rt->rt_expire && rt->rt_expire <= rtems_bsdnet_seconds_since_boot())
136	arptfree(ola); /* timer has expired, clear */
137	}
138	splx(s);
139	}
140
141	/*
142	* Parallel to llc_rtrequest.
143	*/
144	static void
145	arp_rtrequest(int req, struct rtentry rt, struct sockaddr sa)
146	{
147	struct sockaddr *gate;
148	struct llinfo_arp *la;
149	static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK, 0, 0, 0, 0, 0, { 0 } };
150	static int arpinit_done;
151
152	if (!arpinit_done) {
153	arpinit_done = 1;
154	LIST_INIT(&llinfo_arp);
155	timeout(arptimer, (caddr_t)0, hz);
156	}
157	if (rt->rt_flags & RTF_GATEWAY)
158	return;
159	gate = rt->rt_gateway;
160	la = (struct llinfo_arp *)rt->rt_llinfo;
161	switch (req) {
162
163	case RTM_ADD:
164	/*
165	* XXX: If this is a manually added route to interface
166	* such as older version of routed or gated might provide,
167	* restore cloning bit.
168	*/
169	if ((rt->rt_flags & RTF_HOST) == 0 &&
170	rt_mask(rt) != NULL &&
171	SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
172	rt->rt_flags \|= RTF_CLONING;
173	if (rt->rt_flags & RTF_CLONING) {
174	/*
175	* Case 1: This route should come from a route to iface.
176	*/
177	rt_setgate(rt, rt_key(rt),
178	(struct sockaddr *)&null_sdl);
179	gate = rt->rt_gateway;
180	SDL(gate)->sdl_type = rt->rt_ifp->if_type;
181	SDL(gate)->sdl_index = rt->rt_ifp->if_index;
182	rt->rt_expire = rtems_bsdnet_seconds_since_boot();
183	break;
184	}
185	/* Announce a new entry if requested. */
186	if (rt->rt_flags & RTF_ANNOUNCE)
187	arprequest((struct arpcom *)rt->rt_ifp,
188	&SIN(rt_key(rt))->sin_addr.s_addr,
189	&SIN(rt_key(rt))->sin_addr.s_addr,
190	(u_char *)LLADDR(SDL(gate)));
191	/FALLTHROUGH/
192	case RTM_RESOLVE:
193	if (gate->sa_family != AF_LINK \|\|
194	gate->sa_len < sizeof(null_sdl)) {
195	log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
196	break;
197	}
198	SDL(gate)->sdl_type = rt->rt_ifp->if_type;
199	SDL(gate)->sdl_index = rt->rt_ifp->if_index;
200	if (la != 0)
201	break; /* This happens on a route change */
202	/*
203	* Case 2: This route may come from cloning, or a manual route
204	* add with a LL address.
205	*/
206	R_Malloc(la, struct llinfo_arp , sizeof(la));
207	rt->rt_llinfo = (caddr_t)la;
208	if (la == 0) {
209	log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
210	break;
211	}
212	arp_inuse++;
213	arp_allocated++;
214	Bzero(la, sizeof(*la));
215	la->la_rt = rt;
216	rt->rt_flags \|= RTF_LLINFO;
217	LIST_INSERT_HEAD(&llinfo_arp, la, la_le);
218
219	/*
220	* This keeps the multicast addresses from showing up
221	* in `arp -a' listings as unresolved. It's not actually
222	* functional. Then the same for broadcast.
223	*/
224	if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) {
225	ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
226	LLADDR(SDL(gate)));
227	SDL(gate)->sdl_alen = 6;
228	rt->rt_expire = 0;
229	}
230	if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) {
231	memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6);
232	SDL(gate)->sdl_alen = 6;
233	rt->rt_expire = 0;
234	}
235
236	if (SIN(rt_key(rt))->sin_addr.s_addr ==
237	(IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
238	/*
239	* This test used to be
240	* if (loif.if_flags & IFF_UP)
241	* It allowed local traffic to be forced
242	* through the hardware by configuring the loopback down.
243	* However, it causes problems during network configuration
244	* for boards that can't receive packets they send.
245	* It is now necessary to clear "useloopback" and remove
246	* the route to force traffic out to the hardware.
247	*/
248	rt->rt_expire = 0;
249	Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr,
250	LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6);
251	if (useloopback)
252	rt->rt_ifp = loif;
253
254	}
255	break;
256
257	case RTM_DELETE:
258	if (la == 0)
259	break;
260	arp_inuse--;
261	LIST_REMOVE(la, la_le);
262	rt->rt_llinfo = 0;
263	rt->rt_flags &= ~RTF_LLINFO;
264	if (la->la_hold)
265	m_freem(la->la_hold);
266	Free((caddr_t)la);
267	}
268	}
269
270	/*
271	* Broadcast an ARP request. Caller specifies:
272	* - arp header source ip address
273	* - arp header target ip address
274	* - arp header source ethernet address
275	*/
276	static void
277	arprequest(struct arpcom ac, u_long sip, u_long tip, u_char enaddr)
278	{
279	struct mbuf *m;
280	struct ether_header *eh;
281	struct ether_arp *ea;
282	struct sockaddr sa;
283
284	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
285	return;
286	m->m_len = sizeof(*ea);
287	m->m_pkthdr.len = sizeof(*ea);
288	MH_ALIGN(m, sizeof(*ea));
289	ea = mtod(m, struct ether_arp *);
290	eh = (struct ether_header *)sa.sa_data;
291	bzero((caddr_t)ea, sizeof (*ea));
292	(void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost));
293	eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */
294	ea->arp_hrd = htons(ARPHRD_ETHER);
295	ea->arp_pro = htons(ETHERTYPE_IP);
296	ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */
297	ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */
298	ea->arp_op = htons(ARPOP_REQUEST);
299	(void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha));
300	(void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa));
301	(void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa));
302	sa.sa_family = AF_UNSPEC;
303	sa.sa_len = sizeof(sa);
304	(ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry )0);
305	}
306
307	/*
308	* Resolve an IP address into an ethernet address. If success,
309	* desten is filled in. If there is no entry in arptab,
310	* set one up and broadcast a request for the IP address.
311	* Hold onto this mbuf and resend it once the address
312	* is finally resolved. A return value of 1 indicates
313	* that desten has been filled in and the packet should be sent
314	* normally; a 0 return indicates that the packet has been
315	* taken over here, either now or for later transmission.
316	*/
317	int
318	arpresolve(
319	struct arpcom *ac,
320	struct rtentry *rt,
321	struct mbuf *m,
322	struct sockaddr *dst,
323	u_char *desten,
324	struct rtentry *rt0)
325	{
326	struct llinfo_arp *la = 0;
327	struct sockaddr_dl *sdl;
328
329	if (m->m_flags & M_BCAST) { /* broadcast */
330	(void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr));
331	return (1);
332	}
333	if (m->m_flags & M_MCAST) { /* multicast */
334	ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
335	return(1);
336	}
337	if (rt)
338	la = (struct llinfo_arp *)rt->rt_llinfo;
339	else {
340	la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0);
341	if (la)
342	rt = la->la_rt;
343	}
344	if (la == 0 \|\| rt == 0) {
345	log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s\n",
346	inet_ntoa(SIN(dst)->sin_addr));
347	m_freem(m);
348	return (0);
349	}
350	sdl = SDL(rt->rt_gateway);
351	/*
352	* Check the address family and length is valid, the address
353	* is resolved; otherwise, try to resolve.
354	*/
355	if ((rt->rt_expire == 0 \|\| rt->rt_expire > rtems_bsdnet_seconds_since_boot()) &&
356	sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
357	bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
358	return 1;
359	}
360	/*
361	* There is an arptab entry, but no ethernet address
362	* response yet. Replace the held mbuf with this
363	* latest one.
364	*/
365	if (la->la_hold)
366	m_freem(la->la_hold);
367	la->la_hold = m;
368	if (rt->rt_expire) {
369	rt->rt_flags &= ~RTF_REJECT;
370	if (la->la_asked == 0 \|\| rt->rt_expire != rtems_bsdnet_seconds_since_boot()) {
371	rt->rt_expire = rtems_bsdnet_seconds_since_boot();
372	if (la->la_asked++ < arp_maxtries)
373	arprequest(ac,
374	&(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr),
375	&(SIN(dst)->sin_addr.s_addr),
376	ac->ac_enaddr);
377	else {
378	rt->rt_flags \|= RTF_REJECT;
379	rt->rt_expire += arpt_down;
380	la->la_asked = 0;
381	}
382
383	}
384	}
385	return (0);
386	}
387
388	/*
389	* Common length and type checks are done here,
390	* then the protocol-specific routine is called.
391	*/
392	void
393	arpintr(void)
394	{
395	struct mbuf *m;
396	struct arphdr *ar;
397	int s;
398
399	while (arpintrq.ifq_head) {
400	s = splimp();
401	IF_DEQUEUE(&arpintrq, m);
402	splx(s);
403	if (m == 0 \|\| (m->m_flags & M_PKTHDR) == 0)
404	panic("arpintr");
405	if (m->m_len >= sizeof(struct arphdr) &&
406	(ar = mtod(m, struct arphdr *)) &&
407	ntohs(ar->ar_hrd) == ARPHRD_ETHER &&
408	m->m_len >=
409	sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
410
411	switch (ntohs(ar->ar_pro)) {
412
413	case ETHERTYPE_IP:
414	in_arpinput(m);
415	continue;
416	}
417	m_freem(m);
418	}
419	}
420
421	NETISR_SET(NETISR_ARP, arpintr);
422
423	/*
424	* ARP for Internet protocols on 10 Mb/s Ethernet.
425	* Algorithm is that given in RFC 826.
426	* In addition, a sanity check is performed on the sender
427	* protocol address, to catch impersonators.
428	* We no longer handle negotiations for use of trailer protocol:
429	* Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
430	* along with IP replies if we wanted trailers sent to us,
431	* and also sent them in response to IP replies.
432	* This allowed either end to announce the desire to receive
433	* trailer packets.
434	* We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
435	* but formerly didn't normally send requests.
436	*/
437	static void
438	in_arpinput(struct mbuf *m)
439	{
440	struct ether_arp *ea;
441	struct arpcom ac = (struct arpcom )m->m_pkthdr.rcvif;
442	struct ether_header *eh;
443	struct llinfo_arp *la = 0;
444	struct rtentry *rt;
445	struct in_ifaddr *ia;
446	struct in_ifaddr *maybe_ia = 0;
447	struct sockaddr_dl *sdl;
448	struct sockaddr sa;
449	struct in_addr isaddr, itaddr, myaddr;
450	int op;
451
452	ea = mtod(m, struct ether_arp *);
453	op = ntohs(ea->arp_op);
454	(void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr));
455	(void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr));
456	for (ia = in_ifaddr; ia; ia = ia->ia_next)
457	if (ia->ia_ifp == &ac->ac_if) {
458	maybe_ia = ia;
459	if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) \|\|
460	(isaddr.s_addr == ia->ia_addr.sin_addr.s_addr))
461	break;
462	}
463	if (maybe_ia == 0) {
464	m_freem(m);
465	return;
466	}
467	myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr;
468	if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr,
469	sizeof (ea->arp_sha))) {
470	m_freem(m); /* it's from me, ignore it. */
471	return;
472	}
473	if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr,
474	sizeof (ea->arp_sha))) {
475	log(LOG_ERR,
476	"arp: ether address is broadcast for IP address %s!\n",
477	inet_ntoa(isaddr));
478	m_freem(m);
479	return;
480	}
481	if (isaddr.s_addr == myaddr.s_addr) {
482	log(LOG_ERR,
483	"arp: %6D is using my IP address %s!\n",
484	ea->arp_sha, ":", inet_ntoa(isaddr));
485	itaddr = myaddr;
486	goto reply;
487	}
488	la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);
489	if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
490	if (sdl->sdl_alen &&
491	bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen))
492	log(LOG_INFO, "arp: %s moved from %6D to %6D\n",
493	inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":",
494	ea->arp_sha, ":");
495	(void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha));
496	sdl->sdl_alen = sizeof(ea->arp_sha);
497	if (rt->rt_expire)
498	rt->rt_expire = rtems_bsdnet_seconds_since_boot() + arpt_keep;
499	rt->rt_flags &= ~RTF_REJECT;
500	la->la_asked = 0;
501	if (la->la_hold) {
502	(*ac->ac_if.if_output)(&ac->ac_if, la->la_hold,
503	rt_key(rt), rt);
504	la->la_hold = 0;
505	}
506	}
507	reply:
508	if (op != ARPOP_REQUEST) {
509	m_freem(m);
510	return;
511	}
512	if (itaddr.s_addr == myaddr.s_addr) {
513	/* I am the target */
514	(void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha));
515	(void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha));
516	} else {
517	la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
518	if (la == NULL) {
519	struct sockaddr_in sin;
520
521	if (!arp_proxyall) {
522	m_freem(m);
523	return;
524	}
525
526	bzero(&sin, sizeof sin);
527	sin.sin_family = AF_INET;
528	sin.sin_len = sizeof sin;
529	sin.sin_addr = itaddr;
530
531	rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
532	if (!rt) {
533	m_freem(m);
534	return;
535	}
536	/*
537	* Don't send proxies for nodes on the same interface
538	* as this one came out of, or we'll get into a fight
539	* over who claims what Ether address.
540	*/
541	if (rt->rt_ifp == &ac->ac_if) {
542	rtfree(rt);
543	m_freem(m);
544	return;
545	}
546	(void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha));
547	(void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha));
548	rtfree(rt);
549	#ifdef DEBUG_PROXY
550	printf("arp: proxying for %s\n",
551	inet_ntoa(itaddr));
552	#endif
553	} else {
554	rt = la->la_rt;
555	(void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha));
556	sdl = SDL(rt->rt_gateway);
557	(void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha));
558	}
559	}
560
561	(void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa));
562	(void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa));
563	ea->arp_op = htons(ARPOP_REPLY);
564	ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */
565	eh = (struct ether_header *)sa.sa_data;
566	(void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost));
567	eh->ether_type = htons(ETHERTYPE_ARP);
568	sa.sa_family = AF_UNSPEC;
569	sa.sa_len = sizeof(sa);
570	(ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry )0);
571	return;
572	}
573
574	/*
575	* Free an arp entry.
576	*/
577	static void
578	arptfree(struct llinfo_arp *la)
579	{
580	struct rtentry *rt = la->la_rt;
581	struct sockaddr_dl *sdl;
582	if (rt == 0)
583	panic("arptfree");
584	if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
585	sdl->sdl_family == AF_LINK) {
586	sdl->sdl_alen = 0;
587	la->la_asked = 0;
588	rt->rt_flags &= ~RTF_REJECT;
589	return;
590	}
591	rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
592	0, (struct rtentry **)0);
593	}
594	/*
595	* Lookup or enter a new address in arptab.
596	*/
597	static struct llinfo_arp *
598	arplookup(u_long addr, int create, int proxy)
599	{
600	struct rtentry *rt;
601	static struct sockaddr_inarp sin = {sizeof(sin), AF_INET, 0, { 0 }, { 0 }, 0, 0 };
602	const char *why = 0;
603
604	sin.sin_len = sizeof(sin);
605	sin.sin_family = AF_INET;
606	sin.sin_addr.s_addr = addr;
607	sin.sin_other = proxy ? SIN_PROXY : 0;
608	rt = rtalloc1((struct sockaddr *)&sin, create, 0UL);
609	if (rt == 0)
610	return (0);
611	rt->rt_refcnt--;
612
613	if (rt->rt_flags & RTF_GATEWAY)
614	why = "host is not on local network";
615	else if ((rt->rt_flags & RTF_LLINFO) == 0)
616	why = "could not allocate llinfo";
617	else if (rt->rt_gateway->sa_family != AF_LINK)
618	why = "gateway route is not ours";
619
620	if (why && create) {
621	log(LOG_DEBUG, "arplookup %s failed: %s\n",
622	inet_ntoa(sin.sin_addr), why);
623	return 0;
624	} else if (why) {
625	return 0;
626	}
627	return ((struct llinfo_arp *)rt->rt_llinfo);
628	}
629
630	void
631	arp_ifinit(struct arpcom ac, struct ifaddr ifa)
632	{
633	if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
634	arprequest(ac, &(IA_SIN(ifa)->sin_addr.s_addr),
635	&(IA_SIN(ifa)->sin_addr.s_addr), ac->ac_enaddr);
636	ifa->ifa_rtrequest = arp_rtrequest;
637	ifa->ifa_flags \|= RTF_CLONING;
638	}

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