2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
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.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
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
15 * without specific prior written permission.
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)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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>
67 #if defined(INET) || defined(INET6)
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 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
81 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 static VNET_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
94 #define V_arpt_keep VNET(arpt_keep)
95 #define V_arpt_down VNET(arpt_down)
96 #define V_arp_maxtries VNET(arp_maxtries)
97 #define V_arp_proxyall VNET(arp_proxyall)
98 #define V_arpstat VNET(arpstat)
100 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
101 &VNET_NAME(arpt_keep), 0,
102 "ARP entry lifetime in seconds");
103 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
104 &VNET_NAME(arp_maxtries), 0,
105 "ARP resolution attempts before returning error");
106 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
107 &VNET_NAME(useloopback), 0,
108 "Use the loopback interface for local traffic");
109 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
110 &VNET_NAME(arp_proxyall), 0,
111 "Enable proxy ARP for all suitable requests");
112 SYSCTL_VNET_STRUCT(_net_link_ether_arp, OID_AUTO, stats, CTLFLAG_RW,
113 &VNET_NAME(arpstat), arpstat,
114 "ARP statistics (struct arpstat, net/if_arp.h)");
116 static void arp_init(void);
117 void arprequest(struct ifnet *,
118 struct in_addr *, struct in_addr *, u_char *);
119 static void arpintr(struct mbuf *);
120 static void arptimer(void *);
122 static void in_arpinput(struct mbuf *);
125 static const struct netisr_handler arp_nh = {
127 .nh_handler = arpintr,
128 .nh_proto = NETISR_ARP,
129 .nh_policy = NETISR_POLICY_SOURCE,
133 void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
136 * called by in_ifscrub to remove entry from the table when
137 * the interface goes away
140 arp_ifscrub(struct ifnet *ifp, uint32_t addr)
142 struct sockaddr_in addr4;
144 bzero((void *)&addr4, sizeof(addr4));
145 addr4.sin_len = sizeof(addr4);
146 addr4.sin_family = AF_INET;
147 addr4.sin_addr.s_addr = addr;
148 CURVNET_SET(ifp->if_vnet);
150 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
151 (struct sockaddr *)&addr4);
152 IF_AFDATA_UNLOCK(ifp);
158 * Timeout routine. Age arp_tab entries periodically.
166 KASSERT(arg != NULL, ("%s: arg NULL", __func__));
167 lle = (struct llentry *)arg;
168 ifp = lle->lle_tbl->llt_ifp;
169 CURVNET_SET(ifp->if_vnet);
172 if (lle->la_flags & LLE_STATIC)
175 if (!callout_pending(&lle->la_timer) &&
176 callout_active(&lle->la_timer)) {
177 callout_stop(&lle->la_timer);
179 (void) llentry_free(lle);
180 ARPSTAT_INC(timeouts);
184 struct sockaddr *l3addr = L3_ADDR(lle);
186 "arptimer issue: %p, IPv4 address: \"%s\"\n", lle,
188 ((const struct sockaddr_in *)l3addr)->sin_addr));
192 IF_AFDATA_UNLOCK(ifp);
197 * Broadcast an ARP request. Caller specifies:
198 * - arp header source ip address
199 * - arp header target ip address
200 * - arp header source ethernet address
203 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip,
211 /* XXX don't believe this can happen (or explain why) */
213 * The caller did not supply a source address, try to find
214 * a compatible one among those assigned to this interface.
218 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
219 if (!ifa->ifa_addr ||
220 ifa->ifa_addr->sa_family != AF_INET)
222 sip = &SIN(ifa->ifa_addr)->sin_addr;
223 if (0 == ((sip->s_addr ^ tip->s_addr) &
224 SIN(ifa->ifa_netmask)->sin_addr.s_addr) )
225 break; /* found it. */
228 printf("%s: cannot find matching address\n", __func__);
233 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
235 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
236 2*ifp->if_data.ifi_addrlen;
237 m->m_pkthdr.len = m->m_len;
238 MH_ALIGN(m, m->m_len);
239 ah = mtod(m, struct arphdr *);
240 bzero((caddr_t)ah, m->m_len);
242 mac_netinet_arp_send(ifp, m);
244 ah->ar_pro = htons(ETHERTYPE_IP);
245 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
246 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
247 ah->ar_op = htons(ARPOP_REQUEST);
248 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
249 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
250 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
251 sa.sa_family = AF_ARP;
253 m->m_flags |= M_BCAST;
254 (*ifp->if_output)(ifp, m, &sa, NULL);
255 ARPSTAT_INC(txrequests);
259 * Resolve an IP address into an ethernet address.
261 * ifp is the interface we use
262 * rt0 is the route to the final destination (possibly useless)
263 * m is the mbuf. May be NULL if we don't have a packet.
264 * dst is the next hop,
265 * desten is where we want the address.
267 * On success, desten is filled in and the function returns 0;
268 * If the packet must be held pending resolution, we return EWOULDBLOCK
269 * On other errors, we return the corresponding error code.
270 * Note that m_freem() handles NULL.
273 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
274 struct sockaddr *dst, u_char *desten, struct llentry **lle)
276 struct llentry *la = 0;
282 if (m->m_flags & M_BCAST) {
285 ifp->if_broadcastaddr, ifp->if_addrlen);
288 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
290 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
297 IF_AFDATA_RLOCK(ifp);
298 la = lla_lookup(LLTABLE(ifp), flags, dst);
299 IF_AFDATA_RUNLOCK(ifp);
300 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
301 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
302 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
303 IF_AFDATA_WLOCK(ifp);
304 la = lla_lookup(LLTABLE(ifp), flags, dst);
305 IF_AFDATA_WUNLOCK(ifp);
308 if (flags & LLE_CREATE)
310 "arpresolve: can't allocate llinfo for %s\n",
311 inet_ntoa(SIN(dst)->sin_addr));
316 if ((la->la_flags & LLE_VALID) &&
317 ((la->la_flags & LLE_STATIC) || la->la_expire > time_second)) {
318 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
320 * If entry has an expiry time and it is approaching,
321 * see if we need to send an ARP request within this
322 * arpt_down interval.
324 if (!(la->la_flags & LLE_STATIC) &&
325 time_second + la->la_preempt > la->la_expire) {
326 arprequest(ifp, NULL,
327 &SIN(dst)->sin_addr, IF_LLADDR(ifp));
337 if (la->la_flags & LLE_STATIC) { /* should not happen! */
338 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
339 inet_ntoa(SIN(dst)->sin_addr));
345 renew = (la->la_asked == 0 || la->la_expire != time_second);
346 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
347 flags |= LLE_EXCLUSIVE;
352 * There is an arptab entry, but no ethernet address
353 * response yet. Replace the held mbuf with this
357 if (la->la_hold != NULL) {
358 m_freem(la->la_hold);
359 ARPSTAT_INC(dropped);
362 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
363 flags &= ~LLE_EXCLUSIVE;
369 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
370 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
371 * if we have already sent arp_maxtries ARP requests. Retransmit the
372 * ARP request, but not faster than one request per second.
374 if (la->la_asked < V_arp_maxtries)
375 error = EWOULDBLOCK; /* First request. */
377 error = rt0 != NULL && (rt0->rt_flags & RTF_GATEWAY) ?
378 EHOSTUNREACH : EHOSTDOWN;
384 la->la_expire = time_second;
385 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
391 arprequest(ifp, NULL, &SIN(dst)->sin_addr,
396 if (flags & LLE_EXCLUSIVE)
404 * Common length and type checks are done here,
405 * then the protocol-specific routine is called.
408 arpintr(struct mbuf *m)
412 if (m->m_len < sizeof(struct arphdr) &&
413 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
414 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
417 ar = mtod(m, struct arphdr *);
419 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
420 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
421 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
422 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) {
423 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
424 (unsigned char *)&ar->ar_hrd, "");
429 if (m->m_len < arphdr_len(ar)) {
430 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
431 log(LOG_ERR, "arp: runt packet\n");
435 ar = mtod(m, struct arphdr *);
438 ARPSTAT_INC(received);
439 switch (ntohs(ar->ar_pro)) {
451 * ARP for Internet protocols on 10 Mb/s Ethernet.
452 * Algorithm is that given in RFC 826.
453 * In addition, a sanity check is performed on the sender
454 * protocol address, to catch impersonators.
455 * We no longer handle negotiations for use of trailer protocol:
456 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
457 * along with IP replies if we wanted trailers sent to us,
458 * and also sent them in response to IP replies.
459 * This allowed either end to announce the desire to receive
461 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
462 * but formerly didn't normally send requests.
464 static int log_arp_wrong_iface = 1;
465 static int log_arp_movements = 1;
466 static int log_arp_permanent_modify = 1;
468 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
469 &log_arp_wrong_iface, 0,
470 "log arp packets arriving on the wrong interface");
471 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
472 &log_arp_movements, 0,
473 "log arp replies from MACs different than the one in the cache");
474 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
475 &log_arp_permanent_modify, 0,
476 "log arp replies from MACs different than the one in the permanent arp entry");
480 in_arpinput(struct mbuf *m)
483 struct ifnet *ifp = m->m_pkthdr.rcvif;
484 struct llentry *la = NULL;
487 struct in_ifaddr *ia;
490 struct in_addr isaddr, itaddr, myaddr;
491 u_int8_t *enaddr = NULL;
494 int bridged = 0, is_bridge = 0;
496 struct sockaddr_in sin;
497 sin.sin_len = sizeof(struct sockaddr_in);
498 sin.sin_family = AF_INET;
499 sin.sin_addr.s_addr = 0;
503 if (ifp->if_type == IFT_BRIDGE)
506 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
507 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
508 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
512 ah = mtod(m, struct arphdr *);
513 op = ntohs(ah->ar_op);
514 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
515 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
517 if (op == ARPOP_REPLY)
518 ARPSTAT_INC(rxreplies);
521 * For a bridge, we want to check the address irrespective
522 * of the receive interface. (This will change slightly
523 * when we have clusters of interfaces).
524 * If the interface does not match, but the recieving interface
525 * is part of carp, we call carp_iamatch to see if this is a
526 * request for the virtual host ip.
527 * XXX: This is really ugly!
530 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
531 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
532 ia->ia_ifp == ifp) &&
533 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
534 ifa_ref(&ia->ia_ifa);
538 if (ifp->if_carp != NULL &&
539 (*carp_iamatch_p)(ifp, ia, &isaddr, &enaddr) &&
540 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
542 ifa_ref(&ia->ia_ifa);
547 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
548 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
549 ia->ia_ifp == ifp) &&
550 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
551 ifa_ref(&ia->ia_ifa);
556 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
557 (ia->ia_ifp->if_bridge == ifp->if_softc && \
558 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
559 addr == ia->ia_addr.sin_addr.s_addr)
561 * Check the case when bridge shares its MAC address with
562 * some of its children, so packets are claimed by bridge
563 * itself (bridge_input() does it first), but they are really
564 * meant to be destined to the bridge member.
567 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
568 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
569 ifa_ref(&ia->ia_ifa);
576 #undef BDG_MEMBER_MATCHES_ARP
580 * No match, use the first inet address on the receive interface
581 * as a dummy address for the rest of the function.
584 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
585 if (ifa->ifa_addr->sa_family == AF_INET) {
594 * If bridging, fall back to using any inet address.
597 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
601 ifa_ref(&ia->ia_ifa);
605 enaddr = (u_int8_t *)IF_LLADDR(ifp);
606 myaddr = ia->ia_addr.sin_addr;
607 ifa_free(&ia->ia_ifa);
608 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
609 goto drop; /* it's from me, ignore it. */
610 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
612 "arp: link address is broadcast for IP address %s!\n",
617 * Warn if another host is using the same IP address, but only if the
618 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
619 * case we suppress the warning to avoid false positive complaints of
620 * potential misconfiguration.
622 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
624 "arp: %*D is using my IP address %s on %s!\n",
625 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
626 inet_ntoa(isaddr), ifp->if_xname);
631 if (ifp->if_flags & IFF_STATICARP)
634 bzero(&sin, sizeof(sin));
635 sin.sin_len = sizeof(struct sockaddr_in);
636 sin.sin_family = AF_INET;
637 sin.sin_addr = isaddr;
638 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
639 flags |= LLE_EXCLUSIVE;
641 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
642 IF_AFDATA_UNLOCK(ifp);
644 /* the following is not an error when doing bridging */
645 if (!bridged && la->lle_tbl->llt_ifp != ifp && !carp_match) {
646 if (log_arp_wrong_iface)
647 log(LOG_ERR, "arp: %s is on %s "
648 "but got reply from %*D on %s\n",
650 la->lle_tbl->llt_ifp->if_xname,
651 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
656 if ((la->la_flags & LLE_VALID) &&
657 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
658 if (la->la_flags & LLE_STATIC) {
661 "arp: %*D attempts to modify permanent "
662 "entry for %s on %s\n",
663 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
664 inet_ntoa(isaddr), ifp->if_xname);
667 if (log_arp_movements) {
668 log(LOG_INFO, "arp: %s moved from %*D "
672 (u_char *)&la->ll_addr, ":",
673 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
678 if (ifp->if_addrlen != ah->ar_hln) {
681 "arp from %*D: addr len: new %d, i/f %d (ignored)",
682 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
683 ah->ar_hln, ifp->if_addrlen);
686 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
687 la->la_flags |= LLE_VALID;
689 if (!(la->la_flags & LLE_STATIC)) {
693 la->la_expire = time_second + V_arpt_keep;
694 canceled = callout_reset(&la->la_timer,
695 hz * V_arpt_keep, arptimer, la);
700 la->la_preempt = V_arp_maxtries;
704 memcpy(&sa, L3_ADDR(la), sizeof(sa));
708 (*ifp->if_output)(ifp, hold, &sa, NULL);
711 if (op != ARPOP_REQUEST)
713 ARPSTAT_INC(rxrequests);
715 if (itaddr.s_addr == myaddr.s_addr) {
716 /* Shortcut.. the receiving interface is the target. */
717 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
718 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
720 struct llentry *lle = NULL;
722 sin.sin_addr = itaddr;
724 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
725 IF_AFDATA_UNLOCK(ifp);
727 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
728 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
729 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
739 sin.sin_addr = itaddr;
740 /* XXX MRT use table 0 for arp reply */
741 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
746 * Don't send proxies for nodes on the same interface
747 * as this one came out of, or we'll get into a fight
748 * over who claims what Ether address.
750 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
756 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
757 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
760 * Also check that the node which sent the ARP packet
761 * is on the the interface we expect it to be on. This
762 * avoids ARP chaos if an interface is connected to the
765 sin.sin_addr = isaddr;
767 /* XXX MRT use table 0 for arp checks */
768 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
771 if (rt->rt_ifp != ifp) {
772 log(LOG_INFO, "arp_proxy: ignoring request"
773 " from %s via %s, expecting %s\n",
774 inet_ntoa(isaddr), ifp->if_xname,
775 rt->rt_ifp->if_xname);
782 printf("arp: proxying for %s\n",
788 if (itaddr.s_addr == myaddr.s_addr &&
789 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
790 /* RFC 3927 link-local IPv4; always reply by broadcast. */
791 #ifdef DEBUG_LINKLOCAL
792 printf("arp: sending reply for link-local addr %s\n",
795 m->m_flags |= M_BCAST;
796 m->m_flags &= ~M_MCAST;
798 /* default behaviour; never reply by broadcast. */
799 m->m_flags &= ~(M_BCAST|M_MCAST);
801 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
802 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
803 ah->ar_op = htons(ARPOP_REPLY);
804 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
805 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
806 m->m_pkthdr.len = m->m_len;
807 sa.sa_family = AF_ARP;
809 (*ifp->if_output)(ifp, m, &sa, NULL);
810 ARPSTAT_INC(txreplies);
819 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
823 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
824 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
825 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
827 * interface address is considered static entry
828 * because the output of the arp utility shows
829 * that L2 entry as permanent
832 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
833 (struct sockaddr *)IA_SIN(ifa));
834 IF_AFDATA_UNLOCK(ifp);
836 log(LOG_INFO, "arp_ifinit: cannot create arp "
837 "entry for interface address\n");
841 ifa->ifa_rtrequest = NULL;
845 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
847 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
848 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
849 &IA_SIN(ifa)->sin_addr, enaddr);
850 ifa->ifa_rtrequest = NULL;
857 netisr_register(&arp_nh);
859 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);