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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14 * may be used to endorse or promote products derived from this software
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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_dl.h>
56 #include <net/if_types.h>
57 #include <net/netisr.h>
58 #include <net/if_llc.h>
59 #include <net/ethernet.h>
60 #include <net/route.h>
63 #include <netinet/in.h>
64 #include <netinet/in_var.h>
65 #include <net/if_llatbl.h>
66 #include <netinet/if_ether.h>
68 #include <netinet/ip_carp.h>
71 #include <net/if_arc.h>
72 #include <net/iso88025.h>
74 #include <security/mac/mac_framework.h>
76 #define SIN(s) ((const struct sockaddr_in *)(s))
77 #define SDL(s) ((struct sockaddr_dl *)s)
79 SYSCTL_DECL(_net_link_ether);
80 static SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
81 static SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
84 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
86 static VNET_DEFINE(int, arp_maxtries) = 5;
87 VNET_DEFINE(int, useloopback) = 1; /* use loopback interface for
89 static VNET_DEFINE(int, arp_proxyall) = 0;
90 static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for
92 VNET_PCPUSTAT_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
93 VNET_PCPUSTAT_SYSINIT(arpstat);
96 VNET_PCPUSTAT_SYSUNINIT(arpstat);
99 static VNET_DEFINE(int, arp_maxhold) = 1;
101 #define V_arpt_keep VNET(arpt_keep)
102 #define V_arpt_down VNET(arpt_down)
103 #define V_arp_maxtries VNET(arp_maxtries)
104 #define V_arp_proxyall VNET(arp_proxyall)
105 #define V_arp_maxhold VNET(arp_maxhold)
107 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
108 &VNET_NAME(arpt_keep), 0,
109 "ARP entry lifetime in seconds");
110 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
111 &VNET_NAME(arp_maxtries), 0,
112 "ARP resolution attempts before returning error");
113 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
114 &VNET_NAME(useloopback), 0,
115 "Use the loopback interface for local traffic");
116 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
117 &VNET_NAME(arp_proxyall), 0,
118 "Enable proxy ARP for all suitable requests");
119 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, wait, CTLFLAG_RW,
120 &VNET_NAME(arpt_down), 0,
121 "Incomplete ARP entry lifetime in seconds");
122 SYSCTL_VNET_PCPUSTAT(_net_link_ether_arp, OID_AUTO, stats, struct arpstat,
123 arpstat, "ARP statistics (struct arpstat, net/if_arp.h)");
124 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxhold, CTLFLAG_RW,
125 &VNET_NAME(arp_maxhold), 0,
126 "Number of packets to hold per ARP entry");
128 static void arp_init(void);
129 static void arpintr(struct mbuf *);
130 static void arptimer(void *);
132 static void in_arpinput(struct mbuf *);
135 static const struct netisr_handler arp_nh = {
137 .nh_handler = arpintr,
138 .nh_proto = NETISR_ARP,
139 .nh_policy = NETISR_POLICY_SOURCE,
144 * called by in_ifscrub to remove entry from the table when
145 * the interface goes away
148 arp_ifscrub(struct ifnet *ifp, uint32_t addr)
150 struct sockaddr_in addr4;
152 bzero((void *)&addr4, sizeof(addr4));
153 addr4.sin_len = sizeof(addr4);
154 addr4.sin_family = AF_INET;
155 addr4.sin_addr.s_addr = addr;
156 IF_AFDATA_RLOCK(ifp);
157 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
158 (struct sockaddr *)&addr4);
159 IF_AFDATA_RUNLOCK(ifp);
164 * Timeout routine. Age arp_tab entries periodically.
169 struct llentry *lle = (struct llentry *)arg;
172 if (lle->la_flags & LLE_STATIC) {
177 ifp = lle->lle_tbl->llt_ifp;
178 CURVNET_SET(ifp->if_vnet);
180 if ((lle->la_flags & LLE_DELETED) == 0) {
183 if (lle->la_flags & LLE_VALID)
184 evt = LLENTRY_EXPIRED;
186 evt = LLENTRY_TIMEDOUT;
187 EVENTHANDLER_INVOKE(lle_event, lle, evt);
190 callout_stop(&lle->la_timer);
192 /* XXX: LOR avoidance. We still have ref on lle. */
197 /* Guard against race with other llentry_free(). */
198 if (lle->la_flags & LLE_LINKED) {
202 pkts_dropped = llentry_free(lle);
203 ARPSTAT_ADD(dropped, pkts_dropped);
205 LLE_FREE_LOCKED(lle);
207 IF_AFDATA_UNLOCK(ifp);
209 ARPSTAT_INC(timeouts);
215 * Broadcast an ARP request. Caller specifies:
216 * - arp header source ip address
217 * - arp header target ip address
218 * - arp header source ethernet address
221 arprequest(struct ifnet *ifp, const struct in_addr *sip,
222 const struct in_addr *tip, u_char *enaddr)
227 u_char *carpaddr = NULL;
231 * The caller did not supply a source address, try to find
232 * a compatible one among those assigned to this interface.
237 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
238 if (ifa->ifa_addr->sa_family != AF_INET)
242 if ((*carp_iamatch_p)(ifa, &carpaddr) == 0)
244 sip = &IA_SIN(ifa)->sin_addr;
247 sip = &IA_SIN(ifa)->sin_addr;
250 if (0 == ((sip->s_addr ^ tip->s_addr) &
251 IA_MASKSIN(ifa)->sin_addr.s_addr))
252 break; /* found it. */
254 IF_ADDR_RUNLOCK(ifp);
256 printf("%s: cannot find matching address\n", __func__);
261 enaddr = carpaddr ? carpaddr : (u_char *)IF_LLADDR(ifp);
263 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL)
265 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
266 2*ifp->if_data.ifi_addrlen;
267 m->m_pkthdr.len = m->m_len;
268 MH_ALIGN(m, m->m_len);
269 ah = mtod(m, struct arphdr *);
270 bzero((caddr_t)ah, m->m_len);
272 mac_netinet_arp_send(ifp, m);
274 ah->ar_pro = htons(ETHERTYPE_IP);
275 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
276 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
277 ah->ar_op = htons(ARPOP_REQUEST);
278 bcopy(enaddr, ar_sha(ah), ah->ar_hln);
279 bcopy(sip, ar_spa(ah), ah->ar_pln);
280 bcopy(tip, ar_tpa(ah), ah->ar_pln);
281 sa.sa_family = AF_ARP;
283 m->m_flags |= M_BCAST;
284 m_clrprotoflags(m); /* Avoid confusing lower layers. */
285 (*ifp->if_output)(ifp, m, &sa, NULL);
286 ARPSTAT_INC(txrequests);
290 * Resolve an IP address into an ethernet address.
292 * ifp is the interface we use
293 * rt0 is the route to the final destination (possibly useless)
294 * m is the mbuf. May be NULL if we don't have a packet.
295 * dst is the next hop,
296 * desten is where we want the address.
298 * On success, desten is filled in and the function returns 0;
299 * If the packet must be held pending resolution, we return EWOULDBLOCK
300 * On other errors, we return the corresponding error code.
301 * Note that m_freem() handles NULL.
304 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
305 const struct sockaddr *dst, u_char *desten, struct llentry **lle)
307 struct llentry *la = 0;
309 struct mbuf *curr = NULL;
310 struct mbuf *next = NULL;
315 if (m->m_flags & M_BCAST) {
318 ifp->if_broadcastaddr, ifp->if_addrlen);
321 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
323 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
328 IF_AFDATA_RLOCK(ifp);
329 la = lla_lookup(LLTABLE(ifp), flags, dst);
330 IF_AFDATA_RUNLOCK(ifp);
331 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
332 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
333 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
334 IF_AFDATA_WLOCK(ifp);
335 la = lla_lookup(LLTABLE(ifp), flags, dst);
336 IF_AFDATA_WUNLOCK(ifp);
339 if (flags & LLE_CREATE)
341 "arpresolve: can't allocate llinfo for %s on %s\n",
342 inet_ntoa(SIN(dst)->sin_addr), ifp->if_xname);
347 if ((la->la_flags & LLE_VALID) &&
348 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
349 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
351 * If entry has an expiry time and it is approaching,
352 * see if we need to send an ARP request within this
353 * arpt_down interval.
355 if (!(la->la_flags & LLE_STATIC) &&
356 time_uptime + la->la_preempt > la->la_expire) {
357 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
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 = rt0 != NULL && (rt0->rt_flags & RTF_GATEWAY) ?
420 EHOSTUNREACH : EHOSTDOWN;
426 la->la_expire = time_uptime;
427 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
433 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
437 if (flags & LLE_EXCLUSIVE)
445 * Common length and type checks are done here,
446 * then the protocol-specific routine is called.
449 arpintr(struct mbuf *m)
453 if (m->m_len < sizeof(struct arphdr) &&
454 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
455 log(LOG_NOTICE, "arp: runt packet -- m_pullup failed\n");
458 ar = mtod(m, struct arphdr *);
460 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
461 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
462 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
463 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394 &&
464 ntohs(ar->ar_hrd) != ARPHRD_INFINIBAND) {
465 log(LOG_NOTICE, "arp: unknown hardware address format (0x%2D)"
466 " (from %*D to %*D)\n", (unsigned char *)&ar->ar_hrd, "",
467 ETHER_ADDR_LEN, (u_char *)ar_sha(ar), ":",
468 ETHER_ADDR_LEN, (u_char *)ar_tha(ar), ":");
473 if (m->m_len < arphdr_len(ar)) {
474 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
475 log(LOG_NOTICE, "arp: runt packet\n");
479 ar = mtod(m, struct arphdr *);
482 ARPSTAT_INC(received);
483 switch (ntohs(ar->ar_pro)) {
495 * ARP for Internet protocols on 10 Mb/s Ethernet.
496 * Algorithm is that given in RFC 826.
497 * In addition, a sanity check is performed on the sender
498 * protocol address, to catch impersonators.
499 * We no longer handle negotiations for use of trailer protocol:
500 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
501 * along with IP replies if we wanted trailers sent to us,
502 * and also sent them in response to IP replies.
503 * This allowed either end to announce the desire to receive
505 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
506 * but formerly didn't normally send requests.
508 static int log_arp_wrong_iface = 1;
509 static int log_arp_movements = 1;
510 static int log_arp_permanent_modify = 1;
511 static int allow_multicast = 0;
512 static struct timeval arp_lastlog;
513 static int arp_curpps;
514 static int arp_maxpps = 1;
516 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
517 &log_arp_wrong_iface, 0,
518 "log arp packets arriving on the wrong interface");
519 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
520 &log_arp_movements, 0,
521 "log arp replies from MACs different than the one in the cache");
522 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
523 &log_arp_permanent_modify, 0,
524 "log arp replies from MACs different than the one in the permanent arp entry");
525 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW,
526 &allow_multicast, 0, "accept multicast addresses");
527 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_log_per_second,
528 CTLFLAG_RW, &arp_maxpps, 0,
529 "Maximum number of remotely triggered ARP messages that can be "
530 "logged per second");
532 #define ARP_LOG(pri, ...) do { \
533 if (ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \
534 log((pri), "arp: " __VA_ARGS__); \
538 in_arpinput(struct mbuf *m)
541 struct ifnet *ifp = m->m_pkthdr.rcvif;
542 struct llentry *la = NULL;
545 struct in_ifaddr *ia;
547 struct in_addr isaddr, itaddr, myaddr;
548 u_int8_t *enaddr = NULL;
551 int bridged = 0, is_bridge = 0;
553 struct sockaddr_in sin;
554 sin.sin_len = sizeof(struct sockaddr_in);
555 sin.sin_family = AF_INET;
556 sin.sin_addr.s_addr = 0;
560 if (ifp->if_type == IFT_BRIDGE)
563 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
564 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
565 ARP_LOG(LOG_NOTICE, "runt packet -- m_pullup failed\n");
569 ah = mtod(m, struct arphdr *);
571 * ARP is only for IPv4 so we can reject packets with
572 * a protocol length not equal to an IPv4 address.
574 if (ah->ar_pln != sizeof(struct in_addr)) {
575 ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n",
576 sizeof(struct in_addr));
580 if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) {
581 ARP_LOG(LOG_NOTICE, "%*D is multicast\n",
582 ifp->if_addrlen, (u_char *)ar_sha(ah), ":");
586 op = ntohs(ah->ar_op);
587 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
588 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
590 if (op == ARPOP_REPLY)
591 ARPSTAT_INC(rxreplies);
594 * For a bridge, we want to check the address irrespective
595 * of the receive interface. (This will change slightly
596 * when we have clusters of interfaces).
599 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
600 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
601 ia->ia_ifp == ifp) &&
602 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr &&
603 (ia->ia_ifa.ifa_carp == NULL ||
604 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) {
605 ifa_ref(&ia->ia_ifa);
610 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
611 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
612 ia->ia_ifp == ifp) &&
613 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
614 ifa_ref(&ia->ia_ifa);
619 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
620 (ia->ia_ifp->if_bridge == ifp->if_softc && \
621 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
622 addr == ia->ia_addr.sin_addr.s_addr)
624 * Check the case when bridge shares its MAC address with
625 * some of its children, so packets are claimed by bridge
626 * itself (bridge_input() does it first), but they are really
627 * meant to be destined to the bridge member.
630 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
631 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
632 ifa_ref(&ia->ia_ifa);
639 #undef BDG_MEMBER_MATCHES_ARP
643 * No match, use the first inet address on the receive interface
644 * as a dummy address for the rest of the function.
647 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
648 if (ifa->ifa_addr->sa_family == AF_INET &&
649 (ifa->ifa_carp == NULL ||
650 (*carp_iamatch_p)(ifa, &enaddr))) {
653 IF_ADDR_RUNLOCK(ifp);
656 IF_ADDR_RUNLOCK(ifp);
659 * If bridging, fall back to using any inet address.
662 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
666 ifa_ref(&ia->ia_ifa);
670 enaddr = (u_int8_t *)IF_LLADDR(ifp);
671 carped = (ia->ia_ifa.ifa_carp != NULL);
672 myaddr = ia->ia_addr.sin_addr;
673 ifa_free(&ia->ia_ifa);
674 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
675 goto drop; /* it's from me, ignore it. */
676 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
677 ARP_LOG(LOG_NOTICE, "link address is broadcast for IP address "
678 "%s!\n", inet_ntoa(isaddr));
682 * Warn if another host is using the same IP address, but only if the
683 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
684 * case we suppress the warning to avoid false positive complaints of
685 * potential misconfiguration.
687 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr &&
688 myaddr.s_addr != 0) {
689 ARP_LOG(LOG_ERR, "%*D is using my IP address %s on %s!\n",
690 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
691 inet_ntoa(isaddr), ifp->if_xname);
696 if (ifp->if_flags & IFF_STATICARP)
699 bzero(&sin, sizeof(sin));
700 sin.sin_len = sizeof(struct sockaddr_in);
701 sin.sin_family = AF_INET;
702 sin.sin_addr = isaddr;
703 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
704 flags |= LLE_EXCLUSIVE;
706 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
707 IF_AFDATA_UNLOCK(ifp);
709 /* the following is not an error when doing bridging */
710 if (!bridged && la->lle_tbl->llt_ifp != ifp) {
711 if (log_arp_wrong_iface)
712 ARP_LOG(LOG_WARNING, "%s is on %s "
713 "but got reply from %*D on %s\n",
715 la->lle_tbl->llt_ifp->if_xname,
716 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
721 if ((la->la_flags & LLE_VALID) &&
722 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
723 if (la->la_flags & LLE_STATIC) {
725 if (log_arp_permanent_modify)
727 "%*D attempts to modify "
728 "permanent entry for %s on %s\n",
730 (u_char *)ar_sha(ah), ":",
731 inet_ntoa(isaddr), ifp->if_xname);
734 if (log_arp_movements) {
735 ARP_LOG(LOG_INFO, "%s moved from %*D "
739 (u_char *)&la->ll_addr, ":",
740 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
745 if (ifp->if_addrlen != ah->ar_hln) {
747 ARP_LOG(LOG_WARNING, "from %*D: addr len: new %d, "
748 "i/f %d (ignored)\n", ifp->if_addrlen,
749 (u_char *) ar_sha(ah), ":", ah->ar_hln,
753 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
754 la->la_flags |= LLE_VALID;
756 EVENTHANDLER_INVOKE(lle_event, la, LLENTRY_RESOLVED);
758 if (!(la->la_flags & LLE_STATIC)) {
762 la->la_expire = time_uptime + V_arpt_keep;
763 canceled = callout_reset(&la->la_timer,
764 hz * V_arpt_keep, arptimer, la);
769 la->la_preempt = V_arp_maxtries;
771 * The packets are all freed within the call to the output
774 * NB: The lock MUST be released before the call to the
777 if (la->la_hold != NULL) {
778 struct mbuf *m_hold, *m_hold_next;
780 m_hold = la->la_hold;
783 memcpy(&sa, L3_ADDR(la), sizeof(sa));
785 for (; m_hold != NULL; m_hold = m_hold_next) {
786 m_hold_next = m_hold->m_nextpkt;
787 m_hold->m_nextpkt = NULL;
788 /* Avoid confusing lower layers. */
789 m_clrprotoflags(m_hold);
790 (*ifp->if_output)(ifp, m_hold, &sa, NULL);
796 if (op != ARPOP_REQUEST)
798 ARPSTAT_INC(rxrequests);
800 if (itaddr.s_addr == myaddr.s_addr) {
801 /* Shortcut.. the receiving interface is the target. */
802 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
803 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
805 struct llentry *lle = NULL;
807 sin.sin_addr = itaddr;
808 IF_AFDATA_RLOCK(ifp);
809 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
810 IF_AFDATA_RUNLOCK(ifp);
812 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
813 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
814 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
824 sin.sin_addr = itaddr;
825 /* XXX MRT use table 0 for arp reply */
826 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
831 * Don't send proxies for nodes on the same interface
832 * as this one came out of, or we'll get into a fight
833 * over who claims what Ether address.
835 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
841 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
842 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
845 * Also check that the node which sent the ARP packet
846 * is on the interface we expect it to be on. This
847 * avoids ARP chaos if an interface is connected to the
850 sin.sin_addr = isaddr;
852 /* XXX MRT use table 0 for arp checks */
853 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
856 if (rt->rt_ifp != ifp) {
857 ARP_LOG(LOG_INFO, "proxy: ignoring request"
858 " from %s via %s, expecting %s\n",
859 inet_ntoa(isaddr), ifp->if_xname,
860 rt->rt_ifp->if_xname);
867 printf("arp: proxying for %s\n", inet_ntoa(itaddr));
872 if (itaddr.s_addr == myaddr.s_addr &&
873 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
874 /* RFC 3927 link-local IPv4; always reply by broadcast. */
875 #ifdef DEBUG_LINKLOCAL
876 printf("arp: sending reply for link-local addr %s\n",
879 m->m_flags |= M_BCAST;
880 m->m_flags &= ~M_MCAST;
882 /* default behaviour; never reply by broadcast. */
883 m->m_flags &= ~(M_BCAST|M_MCAST);
885 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
886 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
887 ah->ar_op = htons(ARPOP_REPLY);
888 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
889 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
890 m->m_pkthdr.len = m->m_len;
891 m->m_pkthdr.rcvif = NULL;
892 sa.sa_family = AF_ARP;
894 m_clrprotoflags(m); /* Avoid confusing lower layers. */
895 (*ifp->if_output)(ifp, m, &sa, NULL);
896 ARPSTAT_INC(txreplies);
905 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
909 if (ifa->ifa_carp != NULL)
912 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
913 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
914 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
916 * interface address is considered static entry
917 * because the output of the arp utility shows
918 * that L2 entry as permanent
921 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
922 (struct sockaddr *)IA_SIN(ifa));
923 IF_AFDATA_UNLOCK(ifp);
925 log(LOG_INFO, "arp_ifinit: cannot create arp "
926 "entry for interface address\n");
930 ifa->ifa_rtrequest = NULL;
934 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
936 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
937 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
938 &IA_SIN(ifa)->sin_addr, enaddr);
939 ifa->ifa_rtrequest = NULL;
946 netisr_register(&arp_nh);
948 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);