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
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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) ((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_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
94 static VNET_DEFINE(int, arp_maxhold) = 1;
96 #define V_arpt_keep VNET(arpt_keep)
97 #define V_arpt_down VNET(arpt_down)
98 #define V_arp_maxtries VNET(arp_maxtries)
99 #define V_arp_proxyall VNET(arp_proxyall)
100 #define V_arpstat VNET(arpstat)
101 #define V_arp_maxhold VNET(arp_maxhold)
103 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
104 &VNET_NAME(arpt_keep), 0,
105 "ARP entry lifetime in seconds");
106 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
107 &VNET_NAME(arp_maxtries), 0,
108 "ARP resolution attempts before returning error");
109 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
110 &VNET_NAME(useloopback), 0,
111 "Use the loopback interface for local traffic");
112 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
113 &VNET_NAME(arp_proxyall), 0,
114 "Enable proxy ARP for all suitable requests");
115 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, wait, CTLFLAG_RW,
116 &VNET_NAME(arpt_down), 0,
117 "Incomplete ARP entry lifetime in seconds");
118 SYSCTL_VNET_STRUCT(_net_link_ether_arp, OID_AUTO, stats, CTLFLAG_RW,
119 &VNET_NAME(arpstat), arpstat,
120 "ARP statistics (struct arpstat, net/if_arp.h)");
121 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxhold, CTLFLAG_RW,
122 &VNET_NAME(arp_maxhold), 0,
123 "Number of packets to hold per ARP entry");
125 static void arp_init(void);
126 static void arpintr(struct mbuf *);
127 static void arptimer(void *);
129 static void in_arpinput(struct mbuf *);
132 static const struct netisr_handler arp_nh = {
134 .nh_handler = arpintr,
135 .nh_proto = NETISR_ARP,
136 .nh_policy = NETISR_POLICY_SOURCE,
141 * called by in_ifscrub to remove entry from the table when
142 * the interface goes away
145 arp_ifscrub(struct ifnet *ifp, uint32_t addr)
147 struct sockaddr_in addr4;
149 bzero((void *)&addr4, sizeof(addr4));
150 addr4.sin_len = sizeof(addr4);
151 addr4.sin_family = AF_INET;
152 addr4.sin_addr.s_addr = addr;
154 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
155 (struct sockaddr *)&addr4);
156 IF_AFDATA_UNLOCK(ifp);
161 * Timeout routine. Age arp_tab entries periodically.
170 KASSERT(arg != NULL, ("%s: arg NULL", __func__));
171 lle = (struct llentry *)arg;
172 ifp = lle->lle_tbl->llt_ifp;
173 CURVNET_SET(ifp->if_vnet);
176 if (lle->la_flags & LLE_STATIC)
179 if (!callout_pending(&lle->la_timer) &&
180 callout_active(&lle->la_timer)) {
181 callout_stop(&lle->la_timer);
183 pkts_dropped = llentry_free(lle);
184 ARPSTAT_ADD(dropped, pkts_dropped);
185 ARPSTAT_INC(timeouts);
188 struct sockaddr *l3addr = L3_ADDR(lle);
190 "arptimer issue: %p, IPv4 address: \"%s\"\n", lle,
192 ((const struct sockaddr_in *)l3addr)->sin_addr));
197 IF_AFDATA_UNLOCK(ifp);
202 * Broadcast an ARP request. Caller specifies:
203 * - arp header source ip address
204 * - arp header target ip address
205 * - arp header source ethernet address
208 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip,
214 u_char *carpaddr = NULL;
218 * The caller did not supply a source address, try to find
219 * a compatible one among those assigned to this interface.
224 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
225 if (ifa->ifa_addr->sa_family != AF_INET)
229 if ((*carp_iamatch_p)(ifa, &carpaddr) == 0)
231 sip = &IA_SIN(ifa)->sin_addr;
234 sip = &IA_SIN(ifa)->sin_addr;
237 if (0 == ((sip->s_addr ^ tip->s_addr) &
238 IA_MASKSIN(ifa)->sin_addr.s_addr))
239 break; /* found it. */
241 IF_ADDR_RUNLOCK(ifp);
243 printf("%s: cannot find matching address\n", __func__);
248 enaddr = carpaddr ? carpaddr : (u_char *)IF_LLADDR(ifp);
250 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
252 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
253 2*ifp->if_data.ifi_addrlen;
254 m->m_pkthdr.len = m->m_len;
255 MH_ALIGN(m, m->m_len);
256 ah = mtod(m, struct arphdr *);
257 bzero((caddr_t)ah, m->m_len);
259 mac_netinet_arp_send(ifp, m);
261 ah->ar_pro = htons(ETHERTYPE_IP);
262 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
263 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
264 ah->ar_op = htons(ARPOP_REQUEST);
265 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
266 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
267 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
268 sa.sa_family = AF_ARP;
270 m->m_flags |= M_BCAST;
271 (*ifp->if_output)(ifp, m, &sa, NULL);
272 ARPSTAT_INC(txrequests);
276 * Resolve an IP address into an ethernet address.
278 * ifp is the interface we use
279 * rt0 is the route to the final destination (possibly useless)
280 * m is the mbuf. May be NULL if we don't have a packet.
281 * dst is the next hop,
282 * desten is where we want the address.
284 * On success, desten is filled in and the function returns 0;
285 * If the packet must be held pending resolution, we return EWOULDBLOCK
286 * On other errors, we return the corresponding error code.
287 * Note that m_freem() handles NULL.
290 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
291 struct sockaddr *dst, u_char *desten, struct llentry **lle)
293 struct llentry *la = 0;
295 struct mbuf *curr = NULL;
296 struct mbuf *next = NULL;
301 if (m->m_flags & M_BCAST) {
304 ifp->if_broadcastaddr, ifp->if_addrlen);
307 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
309 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
314 IF_AFDATA_RLOCK(ifp);
315 la = lla_lookup(LLTABLE(ifp), flags, dst);
316 IF_AFDATA_RUNLOCK(ifp);
317 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
318 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
319 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
320 IF_AFDATA_WLOCK(ifp);
321 la = lla_lookup(LLTABLE(ifp), flags, dst);
322 IF_AFDATA_WUNLOCK(ifp);
325 if (flags & LLE_CREATE)
327 "arpresolve: can't allocate llinfo for %s\n",
328 inet_ntoa(SIN(dst)->sin_addr));
333 if ((la->la_flags & LLE_VALID) &&
334 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
335 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
337 * If entry has an expiry time and it is approaching,
338 * see if we need to send an ARP request within this
339 * arpt_down interval.
341 if (!(la->la_flags & LLE_STATIC) &&
342 time_uptime + la->la_preempt > la->la_expire) {
343 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
352 if (la->la_flags & LLE_STATIC) { /* should not happen! */
353 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
354 inet_ntoa(SIN(dst)->sin_addr));
360 renew = (la->la_asked == 0 || la->la_expire != time_uptime);
361 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
362 flags |= LLE_EXCLUSIVE;
367 * There is an arptab entry, but no ethernet address
368 * response yet. Add the mbuf to the list, dropping
369 * the oldest packet if we have exceeded the system
373 if (la->la_numheld >= V_arp_maxhold) {
374 if (la->la_hold != NULL) {
375 next = la->la_hold->m_nextpkt;
376 m_freem(la->la_hold);
379 ARPSTAT_INC(dropped);
382 if (la->la_hold != NULL) {
384 while (curr->m_nextpkt != NULL)
385 curr = curr->m_nextpkt;
390 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
391 flags &= ~LLE_EXCLUSIVE;
397 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
398 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
399 * if we have already sent arp_maxtries ARP requests. Retransmit the
400 * ARP request, but not faster than one request per second.
402 if (la->la_asked < V_arp_maxtries)
403 error = EWOULDBLOCK; /* First request. */
405 error = rt0 != NULL && (rt0->rt_flags & RTF_GATEWAY) ?
406 EHOSTUNREACH : EHOSTDOWN;
412 la->la_expire = time_uptime;
413 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
419 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
423 if (flags & LLE_EXCLUSIVE)
431 * Common length and type checks are done here,
432 * then the protocol-specific routine is called.
435 arpintr(struct mbuf *m)
439 if (m->m_len < sizeof(struct arphdr) &&
440 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
441 log(LOG_NOTICE, "arp: runt packet -- m_pullup failed\n");
444 ar = mtod(m, struct arphdr *);
446 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
447 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
448 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
449 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394 &&
450 ntohs(ar->ar_hrd) != ARPHRD_INFINIBAND) {
451 log(LOG_NOTICE, "arp: unknown hardware address format (0x%2D)"
452 " (from %*D to %*D)\n", (unsigned char *)&ar->ar_hrd, "",
453 ETHER_ADDR_LEN, (u_char *)ar_sha(ar), ":",
454 ETHER_ADDR_LEN, (u_char *)ar_tha(ar), ":");
459 if (m->m_len < arphdr_len(ar)) {
460 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
461 log(LOG_NOTICE, "arp: runt packet\n");
465 ar = mtod(m, struct arphdr *);
468 ARPSTAT_INC(received);
469 switch (ntohs(ar->ar_pro)) {
481 * ARP for Internet protocols on 10 Mb/s Ethernet.
482 * Algorithm is that given in RFC 826.
483 * In addition, a sanity check is performed on the sender
484 * protocol address, to catch impersonators.
485 * We no longer handle negotiations for use of trailer protocol:
486 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
487 * along with IP replies if we wanted trailers sent to us,
488 * and also sent them in response to IP replies.
489 * This allowed either end to announce the desire to receive
491 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
492 * but formerly didn't normally send requests.
494 static int log_arp_wrong_iface = 1;
495 static int log_arp_movements = 1;
496 static int log_arp_permanent_modify = 1;
498 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
499 &log_arp_wrong_iface, 0,
500 "log arp packets arriving on the wrong interface");
501 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
502 &log_arp_movements, 0,
503 "log arp replies from MACs different than the one in the cache");
504 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
505 &log_arp_permanent_modify, 0,
506 "log arp replies from MACs different than the one in the permanent arp entry");
510 in_arpinput(struct mbuf *m)
513 struct ifnet *ifp = m->m_pkthdr.rcvif;
514 struct llentry *la = NULL;
517 struct in_ifaddr *ia;
519 struct in_addr isaddr, itaddr, myaddr;
520 u_int8_t *enaddr = NULL;
523 int bridged = 0, is_bridge = 0;
525 struct sockaddr_in sin;
526 sin.sin_len = sizeof(struct sockaddr_in);
527 sin.sin_family = AF_INET;
528 sin.sin_addr.s_addr = 0;
532 if (ifp->if_type == IFT_BRIDGE)
535 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
536 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
537 log(LOG_NOTICE, "in_arp: runt packet -- m_pullup failed\n");
541 ah = mtod(m, struct arphdr *);
543 * ARP is only for IPv4 so we can reject packets with
544 * a protocol length not equal to an IPv4 address.
546 if (ah->ar_pln != sizeof(struct in_addr)) {
547 log(LOG_NOTICE, "in_arp: requested protocol length != %zu\n",
548 sizeof(struct in_addr));
552 if (ETHER_IS_MULTICAST(ar_sha(ah))) {
553 log(LOG_NOTICE, "in_arp: %*D is multicast\n",
554 ifp->if_addrlen, (u_char *)ar_sha(ah), ":");
558 op = ntohs(ah->ar_op);
559 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
560 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
562 if (op == ARPOP_REPLY)
563 ARPSTAT_INC(rxreplies);
566 * For a bridge, we want to check the address irrespective
567 * of the receive interface. (This will change slightly
568 * when we have clusters of interfaces).
571 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
572 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
573 ia->ia_ifp == ifp) &&
574 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr &&
575 (ia->ia_ifa.ifa_carp == NULL ||
576 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) {
577 ifa_ref(&ia->ia_ifa);
582 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
583 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
584 ia->ia_ifp == ifp) &&
585 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
586 ifa_ref(&ia->ia_ifa);
591 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
592 (ia->ia_ifp->if_bridge == ifp->if_softc && \
593 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
594 addr == ia->ia_addr.sin_addr.s_addr)
596 * Check the case when bridge shares its MAC address with
597 * some of its children, so packets are claimed by bridge
598 * itself (bridge_input() does it first), but they are really
599 * meant to be destined to the bridge member.
602 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
603 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
604 ifa_ref(&ia->ia_ifa);
611 #undef BDG_MEMBER_MATCHES_ARP
615 * No match, use the first inet address on the receive interface
616 * as a dummy address for the rest of the function.
619 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
620 if (ifa->ifa_addr->sa_family == AF_INET &&
621 (ifa->ifa_carp == NULL ||
622 (*carp_iamatch_p)(ifa, &enaddr))) {
625 IF_ADDR_RUNLOCK(ifp);
628 IF_ADDR_RUNLOCK(ifp);
631 * If bridging, fall back to using any inet address.
634 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
638 ifa_ref(&ia->ia_ifa);
642 enaddr = (u_int8_t *)IF_LLADDR(ifp);
643 carped = (ia->ia_ifa.ifa_carp != NULL);
644 myaddr = ia->ia_addr.sin_addr;
645 ifa_free(&ia->ia_ifa);
646 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
647 goto drop; /* it's from me, ignore it. */
648 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
650 "arp: link address is broadcast for IP address %s!\n",
655 * Warn if another host is using the same IP address, but only if the
656 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
657 * case we suppress the warning to avoid false positive complaints of
658 * potential misconfiguration.
660 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr &&
661 myaddr.s_addr != 0) {
662 log(LOG_ERR, "arp: %*D is using my IP address %s on %s!\n",
663 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
664 inet_ntoa(isaddr), ifp->if_xname);
669 if (ifp->if_flags & IFF_STATICARP)
672 bzero(&sin, sizeof(sin));
673 sin.sin_len = sizeof(struct sockaddr_in);
674 sin.sin_family = AF_INET;
675 sin.sin_addr = isaddr;
676 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
677 flags |= LLE_EXCLUSIVE;
679 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
680 IF_AFDATA_UNLOCK(ifp);
682 /* the following is not an error when doing bridging */
683 if (!bridged && la->lle_tbl->llt_ifp != ifp) {
684 if (log_arp_wrong_iface)
685 log(LOG_WARNING, "arp: %s is on %s "
686 "but got reply from %*D on %s\n",
688 la->lle_tbl->llt_ifp->if_xname,
689 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
694 if ((la->la_flags & LLE_VALID) &&
695 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
696 if (la->la_flags & LLE_STATIC) {
698 if (log_arp_permanent_modify)
700 "arp: %*D attempts to modify "
701 "permanent entry for %s on %s\n",
703 (u_char *)ar_sha(ah), ":",
704 inet_ntoa(isaddr), ifp->if_xname);
707 if (log_arp_movements) {
708 log(LOG_INFO, "arp: %s moved from %*D "
712 (u_char *)&la->ll_addr, ":",
713 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
718 if (ifp->if_addrlen != ah->ar_hln) {
720 log(LOG_WARNING, "arp from %*D: addr len: new %d, "
721 "i/f %d (ignored)\n", ifp->if_addrlen,
722 (u_char *) ar_sha(ah), ":", ah->ar_hln,
726 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
727 la->la_flags |= LLE_VALID;
729 EVENTHANDLER_INVOKE(arp_update_event, la);
731 if (!(la->la_flags & LLE_STATIC)) {
735 la->la_expire = time_uptime + V_arpt_keep;
736 canceled = callout_reset(&la->la_timer,
737 hz * V_arpt_keep, arptimer, la);
742 la->la_preempt = V_arp_maxtries;
744 * The packets are all freed within the call to the output
747 * NB: The lock MUST be released before the call to the
750 if (la->la_hold != NULL) {
751 struct mbuf *m_hold, *m_hold_next;
753 m_hold = la->la_hold;
756 memcpy(&sa, L3_ADDR(la), sizeof(sa));
758 for (; m_hold != NULL; m_hold = m_hold_next) {
759 m_hold_next = m_hold->m_nextpkt;
760 m_hold->m_nextpkt = NULL;
761 (*ifp->if_output)(ifp, m_hold, &sa, NULL);
767 if (op != ARPOP_REQUEST)
769 ARPSTAT_INC(rxrequests);
771 if (itaddr.s_addr == myaddr.s_addr) {
772 /* Shortcut.. the receiving interface is the target. */
773 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
774 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
776 struct llentry *lle = NULL;
778 sin.sin_addr = itaddr;
780 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
781 IF_AFDATA_UNLOCK(ifp);
783 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
784 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
785 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
795 sin.sin_addr = itaddr;
796 /* XXX MRT use table 0 for arp reply */
797 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
802 * Don't send proxies for nodes on the same interface
803 * as this one came out of, or we'll get into a fight
804 * over who claims what Ether address.
806 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
812 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
813 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
816 * Also check that the node which sent the ARP packet
817 * is on the interface we expect it to be on. This
818 * avoids ARP chaos if an interface is connected to the
821 sin.sin_addr = isaddr;
823 /* XXX MRT use table 0 for arp checks */
824 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
827 if (rt->rt_ifp != ifp) {
828 log(LOG_INFO, "arp_proxy: ignoring request"
829 " from %s via %s, expecting %s\n",
830 inet_ntoa(isaddr), ifp->if_xname,
831 rt->rt_ifp->if_xname);
838 printf("arp: proxying for %s\n",
844 if (itaddr.s_addr == myaddr.s_addr &&
845 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
846 /* RFC 3927 link-local IPv4; always reply by broadcast. */
847 #ifdef DEBUG_LINKLOCAL
848 printf("arp: sending reply for link-local addr %s\n",
851 m->m_flags |= M_BCAST;
852 m->m_flags &= ~M_MCAST;
854 /* default behaviour; never reply by broadcast. */
855 m->m_flags &= ~(M_BCAST|M_MCAST);
857 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
858 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
859 ah->ar_op = htons(ARPOP_REPLY);
860 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
861 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
862 m->m_pkthdr.len = m->m_len;
863 m->m_pkthdr.rcvif = NULL;
864 sa.sa_family = AF_ARP;
866 (*ifp->if_output)(ifp, m, &sa, NULL);
867 ARPSTAT_INC(txreplies);
876 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
880 if (ifa->ifa_carp != NULL)
883 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
884 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
885 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
887 * interface address is considered static entry
888 * because the output of the arp utility shows
889 * that L2 entry as permanent
892 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
893 (struct sockaddr *)IA_SIN(ifa));
894 IF_AFDATA_UNLOCK(ifp);
896 log(LOG_INFO, "arp_ifinit: cannot create arp "
897 "entry for interface address\n");
901 ifa->ifa_rtrequest = NULL;
905 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
907 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
908 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
909 &IA_SIN(ifa)->sin_addr, enaddr);
910 ifa->ifa_rtrequest = NULL;
917 netisr_register(&arp_nh);
919 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);