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
8 * 1. Redistributions of source code must retain the above copyright
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19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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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("$FreeBSD$");
43 #include <sys/param.h>
44 #include <sys/kernel.h>
45 #include <sys/queue.h>
46 #include <sys/sysctl.h>
47 #include <sys/systm.h>
49 #include <sys/malloc.h>
51 #include <sys/socket.h>
52 #include <sys/syslog.h>
55 #include <net/if_var.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 <netinet/ip_carp.h>
72 #include <net/if_arc.h>
73 #include <net/iso88025.h>
75 #include <security/mac/mac_framework.h>
77 #define SIN(s) ((const struct sockaddr_in *)(s))
78 #define SDL(s) ((struct sockaddr_dl *)s)
80 SYSCTL_DECL(_net_link_ether);
81 static SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
82 static SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
85 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
87 static VNET_DEFINE(int, arp_maxtries) = 5;
88 static VNET_DEFINE(int, arp_proxyall) = 0;
89 static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for
91 VNET_PCPUSTAT_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
92 VNET_PCPUSTAT_SYSINIT(arpstat);
95 VNET_PCPUSTAT_SYSUNINIT(arpstat);
98 static VNET_DEFINE(int, arp_maxhold) = 1;
100 #define V_arpt_keep VNET(arpt_keep)
101 #define V_arpt_down VNET(arpt_down)
102 #define V_arp_maxtries VNET(arp_maxtries)
103 #define V_arp_proxyall VNET(arp_proxyall)
104 #define V_arp_maxhold VNET(arp_maxhold)
106 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_VNET | CTLFLAG_RW,
107 &VNET_NAME(arpt_keep), 0,
108 "ARP entry lifetime in seconds");
109 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_VNET | CTLFLAG_RW,
110 &VNET_NAME(arp_maxtries), 0,
111 "ARP resolution attempts before returning error");
112 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_VNET | CTLFLAG_RW,
113 &VNET_NAME(arp_proxyall), 0,
114 "Enable proxy ARP for all suitable requests");
115 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, wait, CTLFLAG_VNET | CTLFLAG_RW,
116 &VNET_NAME(arpt_down), 0,
117 "Incomplete ARP entry lifetime in seconds");
118 SYSCTL_VNET_PCPUSTAT(_net_link_ether_arp, OID_AUTO, stats, struct arpstat,
119 arpstat, "ARP statistics (struct arpstat, net/if_arp.h)");
120 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxhold, CTLFLAG_VNET | CTLFLAG_RW,
121 &VNET_NAME(arp_maxhold), 0,
122 "Number of packets to hold per ARP entry");
124 static void arp_init(void);
125 static void arpintr(struct mbuf *);
126 static void arptimer(void *);
128 static void in_arpinput(struct mbuf *);
131 static const struct netisr_handler arp_nh = {
133 .nh_handler = arpintr,
134 .nh_proto = NETISR_ARP,
135 .nh_policy = NETISR_POLICY_SOURCE,
140 * called by in_scrubprefix() to remove entry from the table when
141 * the interface goes away
144 arp_ifscrub(struct ifnet *ifp, uint32_t addr)
146 struct sockaddr_in addr4;
148 bzero((void *)&addr4, sizeof(addr4));
149 addr4.sin_len = sizeof(addr4);
150 addr4.sin_family = AF_INET;
151 addr4.sin_addr.s_addr = addr;
152 IF_AFDATA_RLOCK(ifp);
153 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
154 (struct sockaddr *)&addr4);
155 IF_AFDATA_RUNLOCK(ifp);
160 * Timeout routine. Age arp_tab entries periodically.
165 struct llentry *lle = (struct llentry *)arg;
168 if (lle->la_flags & LLE_STATIC) {
172 if (callout_pending(&lle->la_timer)) {
174 * Here we are a bit odd here in the treatment of
175 * active/pending. If the pending bit is set, it got
176 * rescheduled before I ran. The active
177 * bit we ignore, since if it was stopped
178 * in ll_tablefree() and was currently running
179 * it would have return 0 so the code would
180 * not have deleted it since the callout could
181 * not be stopped so we want to go through
182 * with the delete here now. If the callout
183 * was restarted, the pending bit will be back on and
184 * we just want to bail since the callout_reset would
185 * return 1 and our reference would have been removed
186 * by arpresolve() below.
191 ifp = lle->lle_tbl->llt_ifp;
192 CURVNET_SET(ifp->if_vnet);
194 if ((lle->la_flags & LLE_DELETED) == 0) {
197 if (lle->la_flags & LLE_VALID)
198 evt = LLENTRY_EXPIRED;
200 evt = LLENTRY_TIMEDOUT;
201 EVENTHANDLER_INVOKE(lle_event, lle, evt);
204 callout_stop(&lle->la_timer);
206 /* XXX: LOR avoidance. We still have ref on lle. */
211 /* Guard against race with other llentry_free(). */
212 if (lle->la_flags & LLE_LINKED) {
216 pkts_dropped = llentry_free(lle);
217 ARPSTAT_ADD(dropped, pkts_dropped);
219 LLE_FREE_LOCKED(lle);
221 IF_AFDATA_UNLOCK(ifp);
223 ARPSTAT_INC(timeouts);
229 * Broadcast an ARP request. Caller specifies:
230 * - arp header source ip address
231 * - arp header target ip address
232 * - arp header source ethernet address
235 arprequest(struct ifnet *ifp, const struct in_addr *sip,
236 const struct in_addr *tip, u_char *enaddr)
241 u_char *carpaddr = NULL;
245 * The caller did not supply a source address, try to find
246 * a compatible one among those assigned to this interface.
251 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
252 if (ifa->ifa_addr->sa_family != AF_INET)
256 if ((*carp_iamatch_p)(ifa, &carpaddr) == 0)
258 sip = &IA_SIN(ifa)->sin_addr;
261 sip = &IA_SIN(ifa)->sin_addr;
264 if (0 == ((sip->s_addr ^ tip->s_addr) &
265 IA_MASKSIN(ifa)->sin_addr.s_addr))
266 break; /* found it. */
268 IF_ADDR_RUNLOCK(ifp);
270 printf("%s: cannot find matching address\n", __func__);
275 enaddr = carpaddr ? carpaddr : (u_char *)IF_LLADDR(ifp);
277 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL)
279 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
281 m->m_pkthdr.len = m->m_len;
282 M_ALIGN(m, m->m_len);
283 ah = mtod(m, struct arphdr *);
284 bzero((caddr_t)ah, m->m_len);
286 mac_netinet_arp_send(ifp, m);
288 ah->ar_pro = htons(ETHERTYPE_IP);
289 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
290 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
291 ah->ar_op = htons(ARPOP_REQUEST);
292 bcopy(enaddr, ar_sha(ah), ah->ar_hln);
293 bcopy(sip, ar_spa(ah), ah->ar_pln);
294 bcopy(tip, ar_tpa(ah), ah->ar_pln);
295 sa.sa_family = AF_ARP;
297 m->m_flags |= M_BCAST;
298 m_clrprotoflags(m); /* Avoid confusing lower layers. */
299 (*ifp->if_output)(ifp, m, &sa, NULL);
300 ARPSTAT_INC(txrequests);
304 * Resolve an IP address into an ethernet address.
306 * ifp is the interface we use
307 * is_gw != if @dst represents gateway to some destination
308 * m is the mbuf. May be NULL if we don't have a packet.
309 * dst is the next hop,
310 * desten is where we want the address.
311 * flags returns lle entry flags.
313 * On success, desten and flags are filled in and the function returns 0;
314 * If the packet must be held pending resolution, we return EWOULDBLOCK
315 * On other errors, we return the corresponding error code.
316 * Note that m_freem() handles NULL.
319 arpresolve(struct ifnet *ifp, int is_gw, struct mbuf *m,
320 const struct sockaddr *dst, u_char *desten, uint32_t *pflags)
322 struct llentry *la = 0;
324 struct mbuf *curr = NULL;
325 struct mbuf *next = NULL;
332 if (m->m_flags & M_BCAST) {
335 ifp->if_broadcastaddr, ifp->if_addrlen);
338 if (m->m_flags & M_MCAST) {
340 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
345 IF_AFDATA_RLOCK(ifp);
346 la = lla_lookup(LLTABLE(ifp), flags, dst);
347 IF_AFDATA_RUNLOCK(ifp);
348 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
349 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
350 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
351 IF_AFDATA_WLOCK(ifp);
352 la = lla_lookup(LLTABLE(ifp), flags, dst);
353 IF_AFDATA_WUNLOCK(ifp);
356 if (flags & LLE_CREATE)
358 "arpresolve: can't allocate llinfo for %s on %s\n",
359 inet_ntoa(SIN(dst)->sin_addr), ifp->if_xname);
364 if ((la->la_flags & LLE_VALID) &&
365 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
366 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
368 * If entry has an expiry time and it is approaching,
369 * see if we need to send an ARP request within this
370 * arpt_down interval.
372 if (!(la->la_flags & LLE_STATIC) &&
373 time_uptime + la->la_preempt > la->la_expire) {
374 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
379 *pflags = la->la_flags;
384 if (la->la_flags & LLE_STATIC) { /* should not happen! */
385 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
386 inet_ntoa(SIN(dst)->sin_addr));
392 renew = (la->la_asked == 0 || la->la_expire != time_uptime);
393 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
394 flags |= LLE_EXCLUSIVE;
399 * There is an arptab entry, but no ethernet address
400 * response yet. Add the mbuf to the list, dropping
401 * the oldest packet if we have exceeded the system
405 if (la->la_numheld >= V_arp_maxhold) {
406 if (la->la_hold != NULL) {
407 next = la->la_hold->m_nextpkt;
408 m_freem(la->la_hold);
411 ARPSTAT_INC(dropped);
414 if (la->la_hold != NULL) {
416 while (curr->m_nextpkt != NULL)
417 curr = curr->m_nextpkt;
422 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
423 flags &= ~LLE_EXCLUSIVE;
429 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
430 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
431 * if we have already sent arp_maxtries ARP requests. Retransmit the
432 * ARP request, but not faster than one request per second.
434 if (la->la_asked < V_arp_maxtries)
435 error = EWOULDBLOCK; /* First request. */
437 error = is_gw != 0 ? EHOSTUNREACH : EHOSTDOWN;
443 la->la_expire = time_uptime;
444 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
450 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
454 if (flags & LLE_EXCLUSIVE)
462 * Common length and type checks are done here,
463 * then the protocol-specific routine is called.
466 arpintr(struct mbuf *m)
470 if (m->m_len < sizeof(struct arphdr) &&
471 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
472 log(LOG_NOTICE, "arp: runt packet -- m_pullup failed\n");
475 ar = mtod(m, struct arphdr *);
477 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
478 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
479 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
480 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394 &&
481 ntohs(ar->ar_hrd) != ARPHRD_INFINIBAND) {
482 log(LOG_NOTICE, "arp: unknown hardware address format (0x%2D)"
483 " (from %*D to %*D)\n", (unsigned char *)&ar->ar_hrd, "",
484 ETHER_ADDR_LEN, (u_char *)ar_sha(ar), ":",
485 ETHER_ADDR_LEN, (u_char *)ar_tha(ar), ":");
490 if (m->m_len < arphdr_len(ar)) {
491 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
492 log(LOG_NOTICE, "arp: runt packet\n");
496 ar = mtod(m, struct arphdr *);
499 ARPSTAT_INC(received);
500 switch (ntohs(ar->ar_pro)) {
512 * ARP for Internet protocols on 10 Mb/s Ethernet.
513 * Algorithm is that given in RFC 826.
514 * In addition, a sanity check is performed on the sender
515 * protocol address, to catch impersonators.
516 * We no longer handle negotiations for use of trailer protocol:
517 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
518 * along with IP replies if we wanted trailers sent to us,
519 * and also sent them in response to IP replies.
520 * This allowed either end to announce the desire to receive
522 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
523 * but formerly didn't normally send requests.
525 static int log_arp_wrong_iface = 1;
526 static int log_arp_movements = 1;
527 static int log_arp_permanent_modify = 1;
528 static int allow_multicast = 0;
529 static struct timeval arp_lastlog;
530 static int arp_curpps;
531 static int arp_maxpps = 1;
533 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
534 &log_arp_wrong_iface, 0,
535 "log arp packets arriving on the wrong interface");
536 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
537 &log_arp_movements, 0,
538 "log arp replies from MACs different than the one in the cache");
539 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
540 &log_arp_permanent_modify, 0,
541 "log arp replies from MACs different than the one in the permanent arp entry");
542 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW,
543 &allow_multicast, 0, "accept multicast addresses");
544 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_log_per_second,
545 CTLFLAG_RW, &arp_maxpps, 0,
546 "Maximum number of remotely triggered ARP messages that can be "
547 "logged per second");
549 #define ARP_LOG(pri, ...) do { \
550 if (ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \
551 log((pri), "arp: " __VA_ARGS__); \
555 in_arpinput(struct mbuf *m)
558 struct ifnet *ifp = m->m_pkthdr.rcvif;
559 struct llentry *la = NULL;
562 struct in_ifaddr *ia;
564 struct in_addr isaddr, itaddr, myaddr;
565 u_int8_t *enaddr = NULL;
568 int bridged = 0, is_bridge = 0;
570 struct sockaddr_in sin;
571 sin.sin_len = sizeof(struct sockaddr_in);
572 sin.sin_family = AF_INET;
573 sin.sin_addr.s_addr = 0;
577 if (ifp->if_type == IFT_BRIDGE)
580 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
581 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
582 ARP_LOG(LOG_NOTICE, "runt packet -- m_pullup failed\n");
586 ah = mtod(m, struct arphdr *);
588 * ARP is only for IPv4 so we can reject packets with
589 * a protocol length not equal to an IPv4 address.
591 if (ah->ar_pln != sizeof(struct in_addr)) {
592 ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n",
593 sizeof(struct in_addr));
597 if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) {
598 ARP_LOG(LOG_NOTICE, "%*D is multicast\n",
599 ifp->if_addrlen, (u_char *)ar_sha(ah), ":");
603 op = ntohs(ah->ar_op);
604 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
605 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
607 if (op == ARPOP_REPLY)
608 ARPSTAT_INC(rxreplies);
611 * For a bridge, we want to check the address irrespective
612 * of the receive interface. (This will change slightly
613 * when we have clusters of interfaces).
616 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
617 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
618 ia->ia_ifp == ifp) &&
619 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr &&
620 (ia->ia_ifa.ifa_carp == NULL ||
621 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) {
622 ifa_ref(&ia->ia_ifa);
627 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
628 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
629 ia->ia_ifp == ifp) &&
630 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
631 ifa_ref(&ia->ia_ifa);
636 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
637 (ia->ia_ifp->if_bridge == ifp->if_softc && \
638 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
639 addr == ia->ia_addr.sin_addr.s_addr)
641 * Check the case when bridge shares its MAC address with
642 * some of its children, so packets are claimed by bridge
643 * itself (bridge_input() does it first), but they are really
644 * meant to be destined to the bridge member.
647 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
648 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
649 ifa_ref(&ia->ia_ifa);
656 #undef BDG_MEMBER_MATCHES_ARP
660 * No match, use the first inet address on the receive interface
661 * as a dummy address for the rest of the function.
664 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
665 if (ifa->ifa_addr->sa_family == AF_INET &&
666 (ifa->ifa_carp == NULL ||
667 (*carp_iamatch_p)(ifa, &enaddr))) {
670 IF_ADDR_RUNLOCK(ifp);
673 IF_ADDR_RUNLOCK(ifp);
676 * If bridging, fall back to using any inet address.
679 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
683 ifa_ref(&ia->ia_ifa);
687 enaddr = (u_int8_t *)IF_LLADDR(ifp);
688 carped = (ia->ia_ifa.ifa_carp != NULL);
689 myaddr = ia->ia_addr.sin_addr;
690 ifa_free(&ia->ia_ifa);
691 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
692 goto drop; /* it's from me, ignore it. */
693 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
694 ARP_LOG(LOG_NOTICE, "link address is broadcast for IP address "
695 "%s!\n", inet_ntoa(isaddr));
699 * Warn if another host is using the same IP address, but only if the
700 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
701 * case we suppress the warning to avoid false positive complaints of
702 * potential misconfiguration.
704 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr &&
705 myaddr.s_addr != 0) {
706 ARP_LOG(LOG_ERR, "%*D is using my IP address %s on %s!\n",
707 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
708 inet_ntoa(isaddr), ifp->if_xname);
713 if (ifp->if_flags & IFF_STATICARP)
716 bzero(&sin, sizeof(sin));
717 sin.sin_len = sizeof(struct sockaddr_in);
718 sin.sin_family = AF_INET;
719 sin.sin_addr = isaddr;
720 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
721 flags |= LLE_EXCLUSIVE;
723 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
724 IF_AFDATA_UNLOCK(ifp);
726 /* the following is not an error when doing bridging */
727 if (!bridged && la->lle_tbl->llt_ifp != ifp) {
728 if (log_arp_wrong_iface)
729 ARP_LOG(LOG_WARNING, "%s is on %s "
730 "but got reply from %*D on %s\n",
732 la->lle_tbl->llt_ifp->if_xname,
733 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
738 if ((la->la_flags & LLE_VALID) &&
739 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
740 if (la->la_flags & LLE_STATIC) {
742 if (log_arp_permanent_modify)
744 "%*D attempts to modify "
745 "permanent entry for %s on %s\n",
747 (u_char *)ar_sha(ah), ":",
748 inet_ntoa(isaddr), ifp->if_xname);
751 if (log_arp_movements) {
752 ARP_LOG(LOG_INFO, "%s moved from %*D "
756 (u_char *)&la->ll_addr, ":",
757 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
762 if (ifp->if_addrlen != ah->ar_hln) {
764 ARP_LOG(LOG_WARNING, "from %*D: addr len: new %d, "
765 "i/f %d (ignored)\n", ifp->if_addrlen,
766 (u_char *) ar_sha(ah), ":", ah->ar_hln,
770 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
771 la->la_flags |= LLE_VALID;
773 EVENTHANDLER_INVOKE(lle_event, la, LLENTRY_RESOLVED);
775 if (!(la->la_flags & LLE_STATIC)) {
779 la->la_expire = time_uptime + V_arpt_keep;
780 canceled = callout_reset(&la->la_timer,
781 hz * V_arpt_keep, arptimer, la);
786 la->la_preempt = V_arp_maxtries;
788 * The packets are all freed within the call to the output
791 * NB: The lock MUST be released before the call to the
794 if (la->la_hold != NULL) {
795 struct mbuf *m_hold, *m_hold_next;
797 m_hold = la->la_hold;
800 memcpy(&sa, L3_ADDR(la), sizeof(sa));
802 for (; m_hold != NULL; m_hold = m_hold_next) {
803 m_hold_next = m_hold->m_nextpkt;
804 m_hold->m_nextpkt = NULL;
805 /* Avoid confusing lower layers. */
806 m_clrprotoflags(m_hold);
807 (*ifp->if_output)(ifp, m_hold, &sa, NULL);
813 if (op != ARPOP_REQUEST)
815 ARPSTAT_INC(rxrequests);
817 if (itaddr.s_addr == myaddr.s_addr) {
818 /* Shortcut.. the receiving interface is the target. */
819 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
820 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
822 struct llentry *lle = NULL;
824 sin.sin_addr = itaddr;
825 IF_AFDATA_RLOCK(ifp);
826 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
827 IF_AFDATA_RUNLOCK(ifp);
829 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
830 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
831 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
841 sin.sin_addr = itaddr;
842 /* XXX MRT use table 0 for arp reply */
843 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
848 * Don't send proxies for nodes on the same interface
849 * as this one came out of, or we'll get into a fight
850 * over who claims what Ether address.
852 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
858 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
859 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
862 * Also check that the node which sent the ARP packet
863 * is on the interface we expect it to be on. This
864 * avoids ARP chaos if an interface is connected to the
867 sin.sin_addr = isaddr;
869 /* XXX MRT use table 0 for arp checks */
870 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
873 if (rt->rt_ifp != ifp) {
874 ARP_LOG(LOG_INFO, "proxy: ignoring request"
875 " from %s via %s, expecting %s\n",
876 inet_ntoa(isaddr), ifp->if_xname,
877 rt->rt_ifp->if_xname);
884 printf("arp: proxying for %s\n", inet_ntoa(itaddr));
889 if (itaddr.s_addr == myaddr.s_addr &&
890 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
891 /* RFC 3927 link-local IPv4; always reply by broadcast. */
892 #ifdef DEBUG_LINKLOCAL
893 printf("arp: sending reply for link-local addr %s\n",
896 m->m_flags |= M_BCAST;
897 m->m_flags &= ~M_MCAST;
899 /* default behaviour; never reply by broadcast. */
900 m->m_flags &= ~(M_BCAST|M_MCAST);
902 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
903 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
904 ah->ar_op = htons(ARPOP_REPLY);
905 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
906 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
907 m->m_pkthdr.len = m->m_len;
908 m->m_pkthdr.rcvif = NULL;
909 sa.sa_family = AF_ARP;
911 m_clrprotoflags(m); /* Avoid confusing lower layers. */
912 (*ifp->if_output)(ifp, m, &sa, NULL);
913 ARPSTAT_INC(txreplies);
922 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
926 if (ifa->ifa_carp != NULL)
929 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
930 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
931 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
933 * interface address is considered static entry
934 * because the output of the arp utility shows
935 * that L2 entry as permanent
938 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
939 (struct sockaddr *)IA_SIN(ifa));
940 IF_AFDATA_UNLOCK(ifp);
942 log(LOG_INFO, "arp_ifinit: cannot create arp "
943 "entry for interface address\n");
947 ifa->ifa_rtrequest = NULL;
951 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
953 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
954 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
955 &IA_SIN(ifa)->sin_addr, enaddr);
956 ifa->ifa_rtrequest = NULL;
963 netisr_register(&arp_nh);
965 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);