2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
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29 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93
33 * Ethernet address resolution protocol.
35 * add "inuse/lock" bit (or ref. count) along with valid bit
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/kernel.h>
46 #include <sys/queue.h>
47 #include <sys/sysctl.h>
48 #include <sys/systm.h>
50 #include <sys/malloc.h>
52 #include <sys/socket.h>
53 #include <sys/syslog.h>
56 #include <net/if_dl.h>
57 #include <net/if_types.h>
58 #include <net/netisr.h>
59 #include <net/if_llc.h>
60 #include <net/ethernet.h>
61 #include <net/route.h>
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
66 #include <net/if_llatbl.h>
67 #include <netinet/if_ether.h>
69 #include <net/if_arc.h>
70 #include <net/iso88025.h>
73 #include <netinet/ip_carp.h>
76 #include <security/mac/mac_framework.h>
78 #define SIN(s) ((struct sockaddr_in *)s)
79 #define SDL(s) ((struct sockaddr_dl *)s)
81 SYSCTL_DECL(_net_link_ether);
82 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
84 VNET_DEFINE(int, useloopback) = 1; /* use loopback interface for
88 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
90 static VNET_DEFINE(int, arp_maxtries) = 5;
91 static VNET_DEFINE(int, arp_proxyall);
93 #define V_arpt_keep VNET(arpt_keep)
94 #define V_arp_maxtries VNET(arp_maxtries)
95 #define V_arp_proxyall VNET(arp_proxyall)
97 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
98 &VNET_NAME(arpt_keep), 0,
99 "ARP entry lifetime in seconds");
101 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
102 &VNET_NAME(arp_maxtries), 0,
103 "ARP resolution attempts before returning error");
104 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
105 &VNET_NAME(useloopback), 0,
106 "Use the loopback interface for local traffic");
107 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
108 &VNET_NAME(arp_proxyall), 0,
109 "Enable proxy ARP for all suitable requests");
111 static void arp_init(void);
112 void arprequest(struct ifnet *,
113 struct in_addr *, struct in_addr *, u_char *);
114 static void arpintr(struct mbuf *);
115 static void arptimer(void *);
117 static void in_arpinput(struct mbuf *);
120 static const struct netisr_handler arp_nh = {
122 .nh_handler = arpintr,
123 .nh_proto = NETISR_ARP,
124 .nh_policy = NETISR_POLICY_SOURCE,
128 void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
131 * called by in_ifscrub to remove entry from the table when
132 * the interface goes away
135 arp_ifscrub(struct ifnet *ifp, uint32_t addr)
137 struct sockaddr_in addr4;
139 bzero((void *)&addr4, sizeof(addr4));
140 addr4.sin_len = sizeof(addr4);
141 addr4.sin_family = AF_INET;
142 addr4.sin_addr.s_addr = addr;
143 CURVNET_SET(ifp->if_vnet);
145 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
146 (struct sockaddr *)&addr4);
147 IF_AFDATA_UNLOCK(ifp);
153 * Timeout routine. Age arp_tab entries periodically.
159 struct llentry *lle = (struct llentry *)arg;
162 panic("%s: NULL entry!\n", __func__);
165 ifp = lle->lle_tbl->llt_ifp;
168 if (((lle->la_flags & LLE_DELETED)
169 || (time_second >= lle->la_expire))
170 && (!callout_pending(&lle->la_timer) &&
171 callout_active(&lle->la_timer)))
172 (void) llentry_free(lle);
175 * Still valid, just drop our reference
177 LLE_FREE_LOCKED(lle);
179 IF_AFDATA_UNLOCK(ifp);
183 * Broadcast an ARP request. Caller specifies:
184 * - arp header source ip address
185 * - arp header target ip address
186 * - arp header source ethernet address
189 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip,
197 /* XXX don't believe this can happen (or explain why) */
199 * The caller did not supply a source address, try to find
200 * a compatible one among those assigned to this interface.
204 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
205 if (!ifa->ifa_addr ||
206 ifa->ifa_addr->sa_family != AF_INET)
208 sip = &SIN(ifa->ifa_addr)->sin_addr;
209 if (0 == ((sip->s_addr ^ tip->s_addr) &
210 SIN(ifa->ifa_netmask)->sin_addr.s_addr) )
211 break; /* found it. */
214 printf("%s: cannot find matching address\n", __func__);
219 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
221 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
222 2*ifp->if_data.ifi_addrlen;
223 m->m_pkthdr.len = m->m_len;
224 MH_ALIGN(m, m->m_len);
225 ah = mtod(m, struct arphdr *);
226 bzero((caddr_t)ah, m->m_len);
228 mac_netinet_arp_send(ifp, m);
230 ah->ar_pro = htons(ETHERTYPE_IP);
231 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
232 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
233 ah->ar_op = htons(ARPOP_REQUEST);
234 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
235 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
236 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
237 sa.sa_family = AF_ARP;
239 m->m_flags |= M_BCAST;
240 (*ifp->if_output)(ifp, m, &sa, NULL);
244 * Resolve an IP address into an ethernet address.
246 * ifp is the interface we use
247 * rt0 is the route to the final destination (possibly useless)
248 * m is the mbuf. May be NULL if we don't have a packet.
249 * dst is the next hop,
250 * desten is where we want the address.
252 * On success, desten is filled in and the function returns 0;
253 * If the packet must be held pending resolution, we return EWOULDBLOCK
254 * On other errors, we return the corresponding error code.
255 * Note that m_freem() handles NULL.
258 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
259 struct sockaddr *dst, u_char *desten, struct llentry **lle)
261 struct llentry *la = 0;
267 if (m->m_flags & M_BCAST) {
270 ifp->if_broadcastaddr, ifp->if_addrlen);
273 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
275 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
282 IF_AFDATA_RLOCK(ifp);
283 la = lla_lookup(LLTABLE(ifp), flags, dst);
284 IF_AFDATA_RUNLOCK(ifp);
285 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
286 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
287 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
288 IF_AFDATA_WLOCK(ifp);
289 la = lla_lookup(LLTABLE(ifp), flags, dst);
290 IF_AFDATA_WUNLOCK(ifp);
293 if (flags & LLE_CREATE)
295 "arpresolve: can't allocate llinfo for %s\n",
296 inet_ntoa(SIN(dst)->sin_addr));
301 if ((la->la_flags & LLE_VALID) &&
302 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
303 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
305 * If entry has an expiry time and it is approaching,
306 * see if we need to send an ARP request within this
307 * arpt_down interval.
309 if (!(la->la_flags & LLE_STATIC) &&
310 time_uptime + la->la_preempt > la->la_expire) {
311 arprequest(ifp, NULL,
312 &SIN(dst)->sin_addr, IF_LLADDR(ifp));
322 if (la->la_flags & LLE_STATIC) { /* should not happen! */
323 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
324 inet_ntoa(SIN(dst)->sin_addr));
330 renew = (la->la_asked == 0 || la->la_expire != time_uptime);
331 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
332 flags |= LLE_EXCLUSIVE;
337 * There is an arptab entry, but no ethernet address
338 * response yet. Replace the held mbuf with this
342 if (la->la_hold != NULL)
343 m_freem(la->la_hold);
345 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
346 flags &= ~LLE_EXCLUSIVE;
352 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
353 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
354 * if we have already sent arp_maxtries ARP requests. Retransmit the
355 * ARP request, but not faster than one request per second.
357 if (la->la_asked < V_arp_maxtries)
358 error = EWOULDBLOCK; /* First request. */
361 (rt0->rt_flags & RTF_GATEWAY) ? EHOSTDOWN : EHOSTUNREACH;
365 la->la_expire = time_uptime;
366 callout_reset(&la->la_timer, hz, arptimer, la);
369 arprequest(ifp, NULL, &SIN(dst)->sin_addr,
374 if (flags & LLE_EXCLUSIVE)
382 * Common length and type checks are done here,
383 * then the protocol-specific routine is called.
386 arpintr(struct mbuf *m)
390 if (m->m_len < sizeof(struct arphdr) &&
391 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
392 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
395 ar = mtod(m, struct arphdr *);
397 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
398 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
399 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
400 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) {
401 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
402 (unsigned char *)&ar->ar_hrd, "");
407 if (m->m_len < arphdr_len(ar)) {
408 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
409 log(LOG_ERR, "arp: runt packet\n");
413 ar = mtod(m, struct arphdr *);
416 switch (ntohs(ar->ar_pro)) {
428 * ARP for Internet protocols on 10 Mb/s Ethernet.
429 * Algorithm is that given in RFC 826.
430 * In addition, a sanity check is performed on the sender
431 * protocol address, to catch impersonators.
432 * We no longer handle negotiations for use of trailer protocol:
433 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
434 * along with IP replies if we wanted trailers sent to us,
435 * and also sent them in response to IP replies.
436 * This allowed either end to announce the desire to receive
438 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
439 * but formerly didn't normally send requests.
441 static int log_arp_wrong_iface = 1;
442 static int log_arp_movements = 1;
443 static int log_arp_permanent_modify = 1;
445 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
446 &log_arp_wrong_iface, 0,
447 "log arp packets arriving on the wrong interface");
448 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
449 &log_arp_movements, 0,
450 "log arp replies from MACs different than the one in the cache");
451 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
452 &log_arp_permanent_modify, 0,
453 "log arp replies from MACs different than the one in the permanent arp entry");
457 in_arpinput(struct mbuf *m)
460 struct ifnet *ifp = m->m_pkthdr.rcvif;
461 struct llentry *la = NULL;
464 struct in_ifaddr *ia;
466 struct in_addr isaddr, itaddr, myaddr;
467 u_int8_t *enaddr = NULL;
471 int bridged = 0, is_bridge = 0;
475 struct sockaddr_in sin;
476 sin.sin_len = sizeof(struct sockaddr_in);
477 sin.sin_family = AF_INET;
478 sin.sin_addr.s_addr = 0;
482 if (ifp->if_type == IFT_BRIDGE)
485 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
486 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
487 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
491 ah = mtod(m, struct arphdr *);
492 op = ntohs(ah->ar_op);
493 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
494 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
497 * For a bridge, we want to check the address irrespective
498 * of the receive interface. (This will change slightly
499 * when we have clusters of interfaces).
500 * If the interface does not match, but the recieving interface
501 * is part of carp, we call carp_iamatch to see if this is a
502 * request for the virtual host ip.
503 * XXX: This is really ugly!
506 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
507 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
508 ia->ia_ifp == ifp) &&
509 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
510 ifa_ref(&ia->ia_ifa);
515 if (ifp->if_carp != NULL &&
516 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) &&
517 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
519 ifa_ref(&ia->ia_ifa);
525 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
526 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
527 ia->ia_ifp == ifp) &&
528 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
529 ifa_ref(&ia->ia_ifa);
534 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
535 (ia->ia_ifp->if_bridge == ifp->if_softc && \
536 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
537 addr == ia->ia_addr.sin_addr.s_addr)
539 * Check the case when bridge shares its MAC address with
540 * some of its children, so packets are claimed by bridge
541 * itself (bridge_input() does it first), but they are really
542 * meant to be destined to the bridge member.
545 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
546 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
547 ifa_ref(&ia->ia_ifa);
554 #undef BDG_MEMBER_MATCHES_ARP
558 * No match, use the first inet address on the receive interface
559 * as a dummy address for the rest of the function.
562 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
563 if (ifa->ifa_addr->sa_family == AF_INET) {
572 * If bridging, fall back to using any inet address.
575 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
579 ifa_ref(&ia->ia_ifa);
583 enaddr = (u_int8_t *)IF_LLADDR(ifp);
584 myaddr = ia->ia_addr.sin_addr;
585 ifa_free(&ia->ia_ifa);
586 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
587 goto drop; /* it's from me, ignore it. */
588 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
590 "arp: link address is broadcast for IP address %s!\n",
595 * Warn if another host is using the same IP address, but only if the
596 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
597 * case we suppress the warning to avoid false positive complaints of
598 * potential misconfiguration.
600 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
602 "arp: %*D is using my IP address %s on %s!\n",
603 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
604 inet_ntoa(isaddr), ifp->if_xname);
608 if (ifp->if_flags & IFF_STATICARP)
611 bzero(&sin, sizeof(sin));
612 sin.sin_len = sizeof(struct sockaddr_in);
613 sin.sin_family = AF_INET;
614 sin.sin_addr = isaddr;
615 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
616 flags |= LLE_EXCLUSIVE;
618 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
619 IF_AFDATA_UNLOCK(ifp);
621 /* the following is not an error when doing bridging */
622 if (!bridged && la->lle_tbl->llt_ifp != ifp
624 && (ifp->if_type != IFT_CARP || !carp_match)
627 if (log_arp_wrong_iface)
628 log(LOG_ERR, "arp: %s is on %s "
629 "but got reply from %*D on %s\n",
631 la->lle_tbl->llt_ifp->if_xname,
632 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
636 if ((la->la_flags & LLE_VALID) &&
637 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
638 if (la->la_flags & LLE_STATIC) {
640 "arp: %*D attempts to modify permanent "
641 "entry for %s on %s\n",
642 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
643 inet_ntoa(isaddr), ifp->if_xname);
646 if (log_arp_movements) {
647 log(LOG_INFO, "arp: %s moved from %*D "
651 (u_char *)&la->ll_addr, ":",
652 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
657 if (ifp->if_addrlen != ah->ar_hln) {
659 "arp from %*D: addr len: new %d, i/f %d (ignored)",
660 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
661 ah->ar_hln, ifp->if_addrlen);
664 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
665 la->la_flags |= LLE_VALID;
667 if (!(la->la_flags & LLE_STATIC)) {
668 la->la_expire = time_uptime + V_arpt_keep;
669 callout_reset(&la->la_timer, hz * V_arpt_keep,
673 la->la_preempt = V_arp_maxtries;
674 if (la->la_hold != NULL) {
677 memcpy(&sa, L3_ADDR(la), sizeof(sa));
680 (*ifp->if_output)(ifp, m0, &sa, NULL);
685 if (op != ARPOP_REQUEST)
688 if (itaddr.s_addr == myaddr.s_addr) {
689 /* Shortcut.. the receiving interface is the target. */
690 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
691 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
693 struct llentry *lle = NULL;
698 sin.sin_addr = itaddr;
699 /* XXX MRT use table 0 for arp reply */
700 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
705 * Don't send proxies for nodes on the same interface
706 * as this one came out of, or we'll get into a fight
707 * over who claims what Ether address.
709 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
713 IF_AFDATA_LOCK(rt->rt_ifp);
714 lle = lla_lookup(LLTABLE(rt->rt_ifp), 0, (struct sockaddr *)&sin);
715 IF_AFDATA_UNLOCK(rt->rt_ifp);
719 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
720 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
726 * Also check that the node which sent the ARP packet
727 * is on the the interface we expect it to be on. This
728 * avoids ARP chaos if an interface is connected to the
731 sin.sin_addr = isaddr;
733 /* XXX MRT use table 0 for arp checks */
734 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
737 if (rt->rt_ifp != ifp) {
738 log(LOG_INFO, "arp_proxy: ignoring request"
739 " from %s via %s, expecting %s\n",
740 inet_ntoa(isaddr), ifp->if_xname,
741 rt->rt_ifp->if_xname);
748 printf("arp: proxying for %s\n",
755 if (itaddr.s_addr == myaddr.s_addr &&
756 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
757 /* RFC 3927 link-local IPv4; always reply by broadcast. */
758 #ifdef DEBUG_LINKLOCAL
759 printf("arp: sending reply for link-local addr %s\n",
762 m->m_flags |= M_BCAST;
763 m->m_flags &= ~M_MCAST;
765 /* default behaviour; never reply by broadcast. */
766 m->m_flags &= ~(M_BCAST|M_MCAST);
768 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
769 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
770 ah->ar_op = htons(ARPOP_REPLY);
771 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
772 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
773 m->m_pkthdr.len = m->m_len;
774 sa.sa_family = AF_ARP;
776 (*ifp->if_output)(ifp, m, &sa, NULL);
787 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
791 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
792 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
793 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
795 * interface address is considered static entry
796 * because the output of the arp utility shows
797 * that L2 entry as permanent
800 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
801 (struct sockaddr *)IA_SIN(ifa));
802 IF_AFDATA_UNLOCK(ifp);
804 log(LOG_INFO, "arp_ifinit: cannot create arp "
805 "entry for interface address\n");
809 ifa->ifa_rtrequest = NULL;
813 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
815 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
816 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
817 &IA_SIN(ifa)->sin_addr, enaddr);
818 ifa->ifa_rtrequest = NULL;
825 netisr_register(&arp_nh);
827 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);