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
9 * notice, this list of conditions and the following disclaimer.
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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
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17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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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_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) {
173 ifp = lle->lle_tbl->llt_ifp;
174 CURVNET_SET(ifp->if_vnet);
176 if ((lle->la_flags & LLE_DELETED) == 0) {
179 if (lle->la_flags & LLE_VALID)
180 evt = LLENTRY_EXPIRED;
182 evt = LLENTRY_TIMEDOUT;
183 EVENTHANDLER_INVOKE(lle_event, lle, evt);
186 callout_stop(&lle->la_timer);
188 /* XXX: LOR avoidance. We still have ref on lle. */
193 /* Guard against race with other llentry_free(). */
194 if (lle->la_flags & LLE_LINKED) {
198 pkts_dropped = llentry_free(lle);
199 ARPSTAT_ADD(dropped, pkts_dropped);
201 LLE_FREE_LOCKED(lle);
203 IF_AFDATA_UNLOCK(ifp);
205 ARPSTAT_INC(timeouts);
211 * Broadcast an ARP request. Caller specifies:
212 * - arp header source ip address
213 * - arp header target ip address
214 * - arp header source ethernet address
217 arprequest(struct ifnet *ifp, const struct in_addr *sip,
218 const struct in_addr *tip, u_char *enaddr)
223 u_char *carpaddr = NULL;
227 * The caller did not supply a source address, try to find
228 * a compatible one among those assigned to this interface.
233 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
234 if (ifa->ifa_addr->sa_family != AF_INET)
238 if ((*carp_iamatch_p)(ifa, &carpaddr) == 0)
240 sip = &IA_SIN(ifa)->sin_addr;
243 sip = &IA_SIN(ifa)->sin_addr;
246 if (0 == ((sip->s_addr ^ tip->s_addr) &
247 IA_MASKSIN(ifa)->sin_addr.s_addr))
248 break; /* found it. */
250 IF_ADDR_RUNLOCK(ifp);
252 printf("%s: cannot find matching address\n", __func__);
257 enaddr = carpaddr ? carpaddr : (u_char *)IF_LLADDR(ifp);
259 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL)
261 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
263 m->m_pkthdr.len = m->m_len;
264 MH_ALIGN(m, m->m_len);
265 ah = mtod(m, struct arphdr *);
266 bzero((caddr_t)ah, m->m_len);
268 mac_netinet_arp_send(ifp, m);
270 ah->ar_pro = htons(ETHERTYPE_IP);
271 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
272 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
273 ah->ar_op = htons(ARPOP_REQUEST);
274 bcopy(enaddr, ar_sha(ah), ah->ar_hln);
275 bcopy(sip, ar_spa(ah), ah->ar_pln);
276 bcopy(tip, ar_tpa(ah), ah->ar_pln);
277 sa.sa_family = AF_ARP;
279 m->m_flags |= M_BCAST;
280 m_clrprotoflags(m); /* Avoid confusing lower layers. */
281 (*ifp->if_output)(ifp, m, &sa, NULL);
282 ARPSTAT_INC(txrequests);
286 * Resolve an IP address into an ethernet address.
288 * ifp is the interface we use
289 * is_gw != if @dst represents gateway to some destination
290 * m is the mbuf. May be NULL if we don't have a packet.
291 * dst is the next hop,
292 * desten is where we want the address.
293 * flags returns lle entry flags.
295 * On success, desten and flags are filled in and the function returns 0;
296 * If the packet must be held pending resolution, we return EWOULDBLOCK
297 * On other errors, we return the corresponding error code.
298 * Note that m_freem() handles NULL.
301 arpresolve(struct ifnet *ifp, int is_gw, struct mbuf *m,
302 const struct sockaddr *dst, u_char *desten, uint32_t *pflags)
304 struct llentry *la = 0;
306 struct mbuf *curr = NULL;
307 struct mbuf *next = NULL;
314 if (m->m_flags & M_BCAST) {
317 ifp->if_broadcastaddr, ifp->if_addrlen);
320 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
322 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
327 IF_AFDATA_RLOCK(ifp);
328 la = lla_lookup(LLTABLE(ifp), flags, dst);
329 IF_AFDATA_RUNLOCK(ifp);
330 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
331 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
332 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
333 IF_AFDATA_WLOCK(ifp);
334 la = lla_lookup(LLTABLE(ifp), flags, dst);
335 IF_AFDATA_WUNLOCK(ifp);
338 if (flags & LLE_CREATE)
340 "arpresolve: can't allocate llinfo for %s on %s\n",
341 inet_ntoa(SIN(dst)->sin_addr), ifp->if_xname);
346 if ((la->la_flags & LLE_VALID) &&
347 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
348 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
350 * If entry has an expiry time and it is approaching,
351 * see if we need to send an ARP request within this
352 * arpt_down interval.
354 if (!(la->la_flags & LLE_STATIC) &&
355 time_uptime + la->la_preempt > la->la_expire) {
356 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
361 *pflags = la->la_flags;
366 if (la->la_flags & LLE_STATIC) { /* should not happen! */
367 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
368 inet_ntoa(SIN(dst)->sin_addr));
374 renew = (la->la_asked == 0 || la->la_expire != time_uptime);
375 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
376 flags |= LLE_EXCLUSIVE;
381 * There is an arptab entry, but no ethernet address
382 * response yet. Add the mbuf to the list, dropping
383 * the oldest packet if we have exceeded the system
387 if (la->la_numheld >= V_arp_maxhold) {
388 if (la->la_hold != NULL) {
389 next = la->la_hold->m_nextpkt;
390 m_freem(la->la_hold);
393 ARPSTAT_INC(dropped);
396 if (la->la_hold != NULL) {
398 while (curr->m_nextpkt != NULL)
399 curr = curr->m_nextpkt;
404 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
405 flags &= ~LLE_EXCLUSIVE;
411 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
412 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
413 * if we have already sent arp_maxtries ARP requests. Retransmit the
414 * ARP request, but not faster than one request per second.
416 if (la->la_asked < V_arp_maxtries)
417 error = EWOULDBLOCK; /* First request. */
419 error = is_gw != 0 ? EHOSTUNREACH : EHOSTDOWN;
425 la->la_expire = time_uptime;
426 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
432 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
436 if (flags & LLE_EXCLUSIVE)
444 * Common length and type checks are done here,
445 * then the protocol-specific routine is called.
448 arpintr(struct mbuf *m)
452 if (m->m_len < sizeof(struct arphdr) &&
453 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
454 log(LOG_NOTICE, "arp: runt packet -- m_pullup failed\n");
457 ar = mtod(m, struct arphdr *);
459 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
460 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
461 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
462 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394 &&
463 ntohs(ar->ar_hrd) != ARPHRD_INFINIBAND) {
464 log(LOG_NOTICE, "arp: unknown hardware address format (0x%2D)"
465 " (from %*D to %*D)\n", (unsigned char *)&ar->ar_hrd, "",
466 ETHER_ADDR_LEN, (u_char *)ar_sha(ar), ":",
467 ETHER_ADDR_LEN, (u_char *)ar_tha(ar), ":");
472 if (m->m_len < arphdr_len(ar)) {
473 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
474 log(LOG_NOTICE, "arp: runt packet\n");
478 ar = mtod(m, struct arphdr *);
481 ARPSTAT_INC(received);
482 switch (ntohs(ar->ar_pro)) {
494 * ARP for Internet protocols on 10 Mb/s Ethernet.
495 * Algorithm is that given in RFC 826.
496 * In addition, a sanity check is performed on the sender
497 * protocol address, to catch impersonators.
498 * We no longer handle negotiations for use of trailer protocol:
499 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
500 * along with IP replies if we wanted trailers sent to us,
501 * and also sent them in response to IP replies.
502 * This allowed either end to announce the desire to receive
504 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
505 * but formerly didn't normally send requests.
507 static int log_arp_wrong_iface = 1;
508 static int log_arp_movements = 1;
509 static int log_arp_permanent_modify = 1;
510 static int allow_multicast = 0;
511 static struct timeval arp_lastlog;
512 static int arp_curpps;
513 static int arp_maxpps = 1;
515 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
516 &log_arp_wrong_iface, 0,
517 "log arp packets arriving on the wrong interface");
518 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
519 &log_arp_movements, 0,
520 "log arp replies from MACs different than the one in the cache");
521 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
522 &log_arp_permanent_modify, 0,
523 "log arp replies from MACs different than the one in the permanent arp entry");
524 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW,
525 &allow_multicast, 0, "accept multicast addresses");
526 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_log_per_second,
527 CTLFLAG_RW, &arp_maxpps, 0,
528 "Maximum number of remotely triggered ARP messages that can be "
529 "logged per second");
531 #define ARP_LOG(pri, ...) do { \
532 if (ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \
533 log((pri), "arp: " __VA_ARGS__); \
537 in_arpinput(struct mbuf *m)
540 struct ifnet *ifp = m->m_pkthdr.rcvif;
541 struct llentry *la = NULL;
544 struct in_ifaddr *ia;
546 struct in_addr isaddr, itaddr, myaddr;
547 u_int8_t *enaddr = NULL;
550 int bridged = 0, is_bridge = 0;
552 struct sockaddr_in sin;
553 sin.sin_len = sizeof(struct sockaddr_in);
554 sin.sin_family = AF_INET;
555 sin.sin_addr.s_addr = 0;
559 if (ifp->if_type == IFT_BRIDGE)
562 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
563 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
564 ARP_LOG(LOG_NOTICE, "runt packet -- m_pullup failed\n");
568 ah = mtod(m, struct arphdr *);
570 * ARP is only for IPv4 so we can reject packets with
571 * a protocol length not equal to an IPv4 address.
573 if (ah->ar_pln != sizeof(struct in_addr)) {
574 ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n",
575 sizeof(struct in_addr));
579 if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) {
580 ARP_LOG(LOG_NOTICE, "%*D is multicast\n",
581 ifp->if_addrlen, (u_char *)ar_sha(ah), ":");
585 op = ntohs(ah->ar_op);
586 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
587 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
589 if (op == ARPOP_REPLY)
590 ARPSTAT_INC(rxreplies);
593 * For a bridge, we want to check the address irrespective
594 * of the receive interface. (This will change slightly
595 * when we have clusters of interfaces).
598 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
599 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
600 ia->ia_ifp == ifp) &&
601 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr &&
602 (ia->ia_ifa.ifa_carp == NULL ||
603 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) {
604 ifa_ref(&ia->ia_ifa);
609 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
610 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
611 ia->ia_ifp == ifp) &&
612 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
613 ifa_ref(&ia->ia_ifa);
618 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
619 (ia->ia_ifp->if_bridge == ifp->if_softc && \
620 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
621 addr == ia->ia_addr.sin_addr.s_addr)
623 * Check the case when bridge shares its MAC address with
624 * some of its children, so packets are claimed by bridge
625 * itself (bridge_input() does it first), but they are really
626 * meant to be destined to the bridge member.
629 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
630 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
631 ifa_ref(&ia->ia_ifa);
638 #undef BDG_MEMBER_MATCHES_ARP
642 * No match, use the first inet address on the receive interface
643 * as a dummy address for the rest of the function.
646 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
647 if (ifa->ifa_addr->sa_family == AF_INET &&
648 (ifa->ifa_carp == NULL ||
649 (*carp_iamatch_p)(ifa, &enaddr))) {
652 IF_ADDR_RUNLOCK(ifp);
655 IF_ADDR_RUNLOCK(ifp);
658 * If bridging, fall back to using any inet address.
661 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
665 ifa_ref(&ia->ia_ifa);
669 enaddr = (u_int8_t *)IF_LLADDR(ifp);
670 carped = (ia->ia_ifa.ifa_carp != NULL);
671 myaddr = ia->ia_addr.sin_addr;
672 ifa_free(&ia->ia_ifa);
673 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
674 goto drop; /* it's from me, ignore it. */
675 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
676 ARP_LOG(LOG_NOTICE, "link address is broadcast for IP address "
677 "%s!\n", inet_ntoa(isaddr));
681 * Warn if another host is using the same IP address, but only if the
682 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
683 * case we suppress the warning to avoid false positive complaints of
684 * potential misconfiguration.
686 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr &&
687 myaddr.s_addr != 0) {
688 ARP_LOG(LOG_ERR, "%*D is using my IP address %s on %s!\n",
689 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
690 inet_ntoa(isaddr), ifp->if_xname);
695 if (ifp->if_flags & IFF_STATICARP)
698 bzero(&sin, sizeof(sin));
699 sin.sin_len = sizeof(struct sockaddr_in);
700 sin.sin_family = AF_INET;
701 sin.sin_addr = isaddr;
702 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
703 flags |= LLE_EXCLUSIVE;
705 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
706 IF_AFDATA_UNLOCK(ifp);
708 /* the following is not an error when doing bridging */
709 if (!bridged && la->lle_tbl->llt_ifp != ifp) {
710 if (log_arp_wrong_iface)
711 ARP_LOG(LOG_WARNING, "%s is on %s "
712 "but got reply from %*D on %s\n",
714 la->lle_tbl->llt_ifp->if_xname,
715 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
720 if ((la->la_flags & LLE_VALID) &&
721 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
722 if (la->la_flags & LLE_STATIC) {
724 if (log_arp_permanent_modify)
726 "%*D attempts to modify "
727 "permanent entry for %s on %s\n",
729 (u_char *)ar_sha(ah), ":",
730 inet_ntoa(isaddr), ifp->if_xname);
733 if (log_arp_movements) {
734 ARP_LOG(LOG_INFO, "%s moved from %*D "
738 (u_char *)&la->ll_addr, ":",
739 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
744 if (ifp->if_addrlen != ah->ar_hln) {
746 ARP_LOG(LOG_WARNING, "from %*D: addr len: new %d, "
747 "i/f %d (ignored)\n", ifp->if_addrlen,
748 (u_char *) ar_sha(ah), ":", ah->ar_hln,
752 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
753 la->la_flags |= LLE_VALID;
755 EVENTHANDLER_INVOKE(lle_event, la, LLENTRY_RESOLVED);
757 if (!(la->la_flags & LLE_STATIC)) {
761 la->la_expire = time_uptime + V_arpt_keep;
762 canceled = callout_reset(&la->la_timer,
763 hz * V_arpt_keep, arptimer, la);
768 la->la_preempt = V_arp_maxtries;
770 * The packets are all freed within the call to the output
773 * NB: The lock MUST be released before the call to the
776 if (la->la_hold != NULL) {
777 struct mbuf *m_hold, *m_hold_next;
779 m_hold = la->la_hold;
782 memcpy(&sa, L3_ADDR(la), sizeof(sa));
784 for (; m_hold != NULL; m_hold = m_hold_next) {
785 m_hold_next = m_hold->m_nextpkt;
786 m_hold->m_nextpkt = NULL;
787 /* Avoid confusing lower layers. */
788 m_clrprotoflags(m_hold);
789 (*ifp->if_output)(ifp, m_hold, &sa, NULL);
795 if (op != ARPOP_REQUEST)
797 ARPSTAT_INC(rxrequests);
799 if (itaddr.s_addr == myaddr.s_addr) {
800 /* Shortcut.. the receiving interface is the target. */
801 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
802 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
804 struct llentry *lle = NULL;
806 sin.sin_addr = itaddr;
807 IF_AFDATA_RLOCK(ifp);
808 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
809 IF_AFDATA_RUNLOCK(ifp);
811 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
812 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
813 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
823 sin.sin_addr = itaddr;
824 /* XXX MRT use table 0 for arp reply */
825 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
830 * Don't send proxies for nodes on the same interface
831 * as this one came out of, or we'll get into a fight
832 * over who claims what Ether address.
834 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
840 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
841 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
844 * Also check that the node which sent the ARP packet
845 * is on the interface we expect it to be on. This
846 * avoids ARP chaos if an interface is connected to the
849 sin.sin_addr = isaddr;
851 /* XXX MRT use table 0 for arp checks */
852 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
855 if (rt->rt_ifp != ifp) {
856 ARP_LOG(LOG_INFO, "proxy: ignoring request"
857 " from %s via %s, expecting %s\n",
858 inet_ntoa(isaddr), ifp->if_xname,
859 rt->rt_ifp->if_xname);
866 printf("arp: proxying for %s\n", inet_ntoa(itaddr));
871 if (itaddr.s_addr == myaddr.s_addr &&
872 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
873 /* RFC 3927 link-local IPv4; always reply by broadcast. */
874 #ifdef DEBUG_LINKLOCAL
875 printf("arp: sending reply for link-local addr %s\n",
878 m->m_flags |= M_BCAST;
879 m->m_flags &= ~M_MCAST;
881 /* default behaviour; never reply by broadcast. */
882 m->m_flags &= ~(M_BCAST|M_MCAST);
884 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
885 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
886 ah->ar_op = htons(ARPOP_REPLY);
887 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
888 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
889 m->m_pkthdr.len = m->m_len;
890 m->m_pkthdr.rcvif = NULL;
891 sa.sa_family = AF_ARP;
893 m_clrprotoflags(m); /* Avoid confusing lower layers. */
894 (*ifp->if_output)(ifp, m, &sa, NULL);
895 ARPSTAT_INC(txreplies);
904 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
908 if (ifa->ifa_carp != NULL)
911 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
912 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
913 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
915 * interface address is considered static entry
916 * because the output of the arp utility shows
917 * that L2 entry as permanent
920 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
921 (struct sockaddr *)IA_SIN(ifa));
922 IF_AFDATA_UNLOCK(ifp);
924 log(LOG_INFO, "arp_ifinit: cannot create arp "
925 "entry for interface address\n");
929 ifa->ifa_rtrequest = NULL;
933 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
935 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
936 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
937 &IA_SIN(ifa)->sin_addr, enaddr);
938 ifa->ifa_rtrequest = NULL;
945 netisr_register(&arp_nh);
947 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);