2 * Copyright (c) 1982, 1986, 1988, 1993
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6 * modification, are permitted provided that the following conditions
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26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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_WLOCK(ifp);
153 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
154 (struct sockaddr *)&addr4);
155 IF_AFDATA_WUNLOCK(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);
369 * If entry has an expiry time and it is approaching,
370 * see if we need to send an ARP request within this
371 * arpt_down interval.
373 if (!(la->la_flags & LLE_STATIC) &&
374 time_uptime + la->la_preempt > la->la_expire) {
380 *pflags = la->la_flags;
382 if (flags & LLE_EXCLUSIVE)
388 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
393 if (la->la_flags & LLE_STATIC) { /* should not happen! */
394 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
395 inet_ntoa(SIN(dst)->sin_addr));
401 renew = (la->la_asked == 0 || la->la_expire != time_uptime);
402 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
403 flags |= LLE_EXCLUSIVE;
408 * There is an arptab entry, but no ethernet address
409 * response yet. Add the mbuf to the list, dropping
410 * the oldest packet if we have exceeded the system
414 if (la->la_numheld >= V_arp_maxhold) {
415 if (la->la_hold != NULL) {
416 next = la->la_hold->m_nextpkt;
417 m_freem(la->la_hold);
420 ARPSTAT_INC(dropped);
423 if (la->la_hold != NULL) {
425 while (curr->m_nextpkt != NULL)
426 curr = curr->m_nextpkt;
431 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
432 flags &= ~LLE_EXCLUSIVE;
438 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
439 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
440 * if we have already sent arp_maxtries ARP requests. Retransmit the
441 * ARP request, but not faster than one request per second.
443 if (la->la_asked < V_arp_maxtries)
444 error = EWOULDBLOCK; /* First request. */
446 error = is_gw != 0 ? EHOSTUNREACH : EHOSTDOWN;
452 la->la_expire = time_uptime;
453 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
459 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
463 if (flags & LLE_EXCLUSIVE)
471 * Common length and type checks are done here,
472 * then the protocol-specific routine is called.
475 arpintr(struct mbuf *m)
479 if (m->m_len < sizeof(struct arphdr) &&
480 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
481 log(LOG_NOTICE, "arp: runt packet -- m_pullup failed\n");
484 ar = mtod(m, struct arphdr *);
486 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
487 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
488 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
489 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394 &&
490 ntohs(ar->ar_hrd) != ARPHRD_INFINIBAND) {
491 log(LOG_NOTICE, "arp: unknown hardware address format (0x%2D)"
492 " (from %*D to %*D)\n", (unsigned char *)&ar->ar_hrd, "",
493 ETHER_ADDR_LEN, (u_char *)ar_sha(ar), ":",
494 ETHER_ADDR_LEN, (u_char *)ar_tha(ar), ":");
499 if (m->m_len < arphdr_len(ar)) {
500 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
501 log(LOG_NOTICE, "arp: runt packet\n");
505 ar = mtod(m, struct arphdr *);
508 ARPSTAT_INC(received);
509 switch (ntohs(ar->ar_pro)) {
521 * ARP for Internet protocols on 10 Mb/s Ethernet.
522 * Algorithm is that given in RFC 826.
523 * In addition, a sanity check is performed on the sender
524 * protocol address, to catch impersonators.
525 * We no longer handle negotiations for use of trailer protocol:
526 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
527 * along with IP replies if we wanted trailers sent to us,
528 * and also sent them in response to IP replies.
529 * This allowed either end to announce the desire to receive
531 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
532 * but formerly didn't normally send requests.
534 static int log_arp_wrong_iface = 1;
535 static int log_arp_movements = 1;
536 static int log_arp_permanent_modify = 1;
537 static int allow_multicast = 0;
538 static struct timeval arp_lastlog;
539 static int arp_curpps;
540 static int arp_maxpps = 1;
542 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
543 &log_arp_wrong_iface, 0,
544 "log arp packets arriving on the wrong interface");
545 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
546 &log_arp_movements, 0,
547 "log arp replies from MACs different than the one in the cache");
548 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
549 &log_arp_permanent_modify, 0,
550 "log arp replies from MACs different than the one in the permanent arp entry");
551 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW,
552 &allow_multicast, 0, "accept multicast addresses");
553 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_log_per_second,
554 CTLFLAG_RW, &arp_maxpps, 0,
555 "Maximum number of remotely triggered ARP messages that can be "
556 "logged per second");
558 #define ARP_LOG(pri, ...) do { \
559 if (ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \
560 log((pri), "arp: " __VA_ARGS__); \
564 in_arpinput(struct mbuf *m)
567 struct ifnet *ifp = m->m_pkthdr.rcvif;
568 struct llentry *la = NULL;
571 struct in_ifaddr *ia;
573 struct in_addr isaddr, itaddr, myaddr;
574 u_int8_t *enaddr = NULL;
577 int bridged = 0, is_bridge = 0;
579 struct sockaddr_in sin;
580 sin.sin_len = sizeof(struct sockaddr_in);
581 sin.sin_family = AF_INET;
582 sin.sin_addr.s_addr = 0;
586 if (ifp->if_type == IFT_BRIDGE)
589 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
590 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
591 ARP_LOG(LOG_NOTICE, "runt packet -- m_pullup failed\n");
595 ah = mtod(m, struct arphdr *);
597 * ARP is only for IPv4 so we can reject packets with
598 * a protocol length not equal to an IPv4 address.
600 if (ah->ar_pln != sizeof(struct in_addr)) {
601 ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n",
602 sizeof(struct in_addr));
606 if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) {
607 ARP_LOG(LOG_NOTICE, "%*D is multicast\n",
608 ifp->if_addrlen, (u_char *)ar_sha(ah), ":");
612 op = ntohs(ah->ar_op);
613 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
614 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
616 if (op == ARPOP_REPLY)
617 ARPSTAT_INC(rxreplies);
620 * For a bridge, we want to check the address irrespective
621 * of the receive interface. (This will change slightly
622 * when we have clusters of interfaces).
625 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
626 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
627 ia->ia_ifp == ifp) &&
628 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr &&
629 (ia->ia_ifa.ifa_carp == NULL ||
630 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) {
631 ifa_ref(&ia->ia_ifa);
636 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
637 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
638 ia->ia_ifp == ifp) &&
639 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
640 ifa_ref(&ia->ia_ifa);
645 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
646 (ia->ia_ifp->if_bridge == ifp->if_softc && \
647 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
648 addr == ia->ia_addr.sin_addr.s_addr)
650 * Check the case when bridge shares its MAC address with
651 * some of its children, so packets are claimed by bridge
652 * itself (bridge_input() does it first), but they are really
653 * meant to be destined to the bridge member.
656 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
657 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
658 ifa_ref(&ia->ia_ifa);
665 #undef BDG_MEMBER_MATCHES_ARP
669 * No match, use the first inet address on the receive interface
670 * as a dummy address for the rest of the function.
673 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
674 if (ifa->ifa_addr->sa_family == AF_INET &&
675 (ifa->ifa_carp == NULL ||
676 (*carp_iamatch_p)(ifa, &enaddr))) {
679 IF_ADDR_RUNLOCK(ifp);
682 IF_ADDR_RUNLOCK(ifp);
685 * If bridging, fall back to using any inet address.
688 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
692 ifa_ref(&ia->ia_ifa);
696 enaddr = (u_int8_t *)IF_LLADDR(ifp);
697 carped = (ia->ia_ifa.ifa_carp != NULL);
698 myaddr = ia->ia_addr.sin_addr;
699 ifa_free(&ia->ia_ifa);
700 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
701 goto drop; /* it's from me, ignore it. */
702 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
703 ARP_LOG(LOG_NOTICE, "link address is broadcast for IP address "
704 "%s!\n", inet_ntoa(isaddr));
708 * Warn if another host is using the same IP address, but only if the
709 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
710 * case we suppress the warning to avoid false positive complaints of
711 * potential misconfiguration.
713 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr &&
714 myaddr.s_addr != 0) {
715 ARP_LOG(LOG_ERR, "%*D is using my IP address %s on %s!\n",
716 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
717 inet_ntoa(isaddr), ifp->if_xname);
722 if (ifp->if_flags & IFF_STATICARP)
725 bzero(&sin, sizeof(sin));
726 sin.sin_len = sizeof(struct sockaddr_in);
727 sin.sin_family = AF_INET;
728 sin.sin_addr = isaddr;
729 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
730 flags |= LLE_EXCLUSIVE;
732 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
733 IF_AFDATA_UNLOCK(ifp);
735 /* the following is not an error when doing bridging */
736 if (!bridged && la->lle_tbl->llt_ifp != ifp) {
737 if (log_arp_wrong_iface)
738 ARP_LOG(LOG_WARNING, "%s is on %s "
739 "but got reply from %*D on %s\n",
741 la->lle_tbl->llt_ifp->if_xname,
742 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
747 if ((la->la_flags & LLE_VALID) &&
748 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
749 if (la->la_flags & LLE_STATIC) {
751 if (log_arp_permanent_modify)
753 "%*D attempts to modify "
754 "permanent entry for %s on %s\n",
756 (u_char *)ar_sha(ah), ":",
757 inet_ntoa(isaddr), ifp->if_xname);
760 if (log_arp_movements) {
761 ARP_LOG(LOG_INFO, "%s moved from %*D "
765 (u_char *)&la->ll_addr, ":",
766 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
771 if (ifp->if_addrlen != ah->ar_hln) {
773 ARP_LOG(LOG_WARNING, "from %*D: addr len: new %d, "
774 "i/f %d (ignored)\n", ifp->if_addrlen,
775 (u_char *) ar_sha(ah), ":", ah->ar_hln,
779 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
780 la->la_flags |= LLE_VALID;
782 EVENTHANDLER_INVOKE(lle_event, la, LLENTRY_RESOLVED);
784 if (!(la->la_flags & LLE_STATIC)) {
788 la->la_expire = time_uptime + V_arpt_keep;
789 canceled = callout_reset(&la->la_timer,
790 hz * V_arpt_keep, arptimer, la);
795 la->la_preempt = V_arp_maxtries;
797 * The packets are all freed within the call to the output
800 * NB: The lock MUST be released before the call to the
803 if (la->la_hold != NULL) {
804 struct mbuf *m_hold, *m_hold_next;
806 m_hold = la->la_hold;
809 memcpy(&sa, L3_ADDR(la), sizeof(sa));
811 for (; m_hold != NULL; m_hold = m_hold_next) {
812 m_hold_next = m_hold->m_nextpkt;
813 m_hold->m_nextpkt = NULL;
814 /* Avoid confusing lower layers. */
815 m_clrprotoflags(m_hold);
816 (*ifp->if_output)(ifp, m_hold, &sa, NULL);
822 if (op != ARPOP_REQUEST)
824 ARPSTAT_INC(rxrequests);
826 if (itaddr.s_addr == myaddr.s_addr) {
827 /* Shortcut.. the receiving interface is the target. */
828 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
829 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
831 struct llentry *lle = NULL;
833 sin.sin_addr = itaddr;
834 IF_AFDATA_RLOCK(ifp);
835 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
836 IF_AFDATA_RUNLOCK(ifp);
838 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
839 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
840 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
850 sin.sin_addr = itaddr;
851 /* XXX MRT use table 0 for arp reply */
852 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
857 * Don't send proxies for nodes on the same interface
858 * as this one came out of, or we'll get into a fight
859 * over who claims what Ether address.
861 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
867 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
868 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
871 * Also check that the node which sent the ARP packet
872 * is on the interface we expect it to be on. This
873 * avoids ARP chaos if an interface is connected to the
876 sin.sin_addr = isaddr;
878 /* XXX MRT use table 0 for arp checks */
879 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
882 if (rt->rt_ifp != ifp) {
883 ARP_LOG(LOG_INFO, "proxy: ignoring request"
884 " from %s via %s, expecting %s\n",
885 inet_ntoa(isaddr), ifp->if_xname,
886 rt->rt_ifp->if_xname);
893 printf("arp: proxying for %s\n", inet_ntoa(itaddr));
898 if (itaddr.s_addr == myaddr.s_addr &&
899 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
900 /* RFC 3927 link-local IPv4; always reply by broadcast. */
901 #ifdef DEBUG_LINKLOCAL
902 printf("arp: sending reply for link-local addr %s\n",
905 m->m_flags |= M_BCAST;
906 m->m_flags &= ~M_MCAST;
908 /* default behaviour; never reply by broadcast. */
909 m->m_flags &= ~(M_BCAST|M_MCAST);
911 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
912 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
913 ah->ar_op = htons(ARPOP_REPLY);
914 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
915 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
916 m->m_pkthdr.len = m->m_len;
917 m->m_pkthdr.rcvif = NULL;
918 sa.sa_family = AF_ARP;
920 m_clrprotoflags(m); /* Avoid confusing lower layers. */
921 (*ifp->if_output)(ifp, m, &sa, NULL);
922 ARPSTAT_INC(txreplies);
931 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
935 if (ifa->ifa_carp != NULL)
938 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
939 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
940 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
942 * interface address is considered static entry
943 * because the output of the arp utility shows
944 * that L2 entry as permanent
947 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
948 (struct sockaddr *)IA_SIN(ifa));
949 IF_AFDATA_UNLOCK(ifp);
951 log(LOG_INFO, "arp_ifinit: cannot create arp "
952 "entry for interface address\n");
956 ifa->ifa_rtrequest = NULL;
960 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
962 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
963 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
964 &IA_SIN(ifa)->sin_addr, enaddr);
965 ifa->ifa_rtrequest = NULL;
972 netisr_register(&arp_nh);
974 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);