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("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/kernel.h>
46 #include <sys/queue.h>
47 #include <sys/sysctl.h>
48 #include <sys/systm.h>
50 #include <sys/malloc.h>
52 #include <sys/socket.h>
53 #include <sys/syslog.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 <net/if_arc.h>
70 #include <net/iso88025.h>
73 #include <netinet/ip_carp.h>
76 #include <security/mac/mac_framework.h>
78 #define SIN(s) ((struct sockaddr_in *)s)
79 #define SDL(s) ((struct sockaddr_dl *)s)
81 SYSCTL_DECL(_net_link_ether);
82 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
83 SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
85 VNET_DEFINE(int, useloopback) = 1; /* use loopback interface for
89 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
91 static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for
93 static VNET_DEFINE(int, arp_maxtries) = 5;
94 static VNET_DEFINE(int, arp_proxyall);
95 static VNET_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
97 #define V_arpt_keep VNET(arpt_keep)
98 #define V_arpt_down VNET(arpt_down)
99 #define V_arp_maxtries VNET(arp_maxtries)
100 #define V_arp_proxyall VNET(arp_proxyall)
101 #define V_arpstat VNET(arpstat)
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");
107 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
108 &VNET_NAME(arp_maxtries), 0,
109 "ARP resolution attempts before returning error");
110 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
111 &VNET_NAME(useloopback), 0,
112 "Use the loopback interface for local traffic");
113 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
114 &VNET_NAME(arp_proxyall), 0,
115 "Enable proxy ARP for all suitable requests");
116 SYSCTL_VNET_STRUCT(_net_link_ether_arp, OID_AUTO, stats, CTLFLAG_RW,
117 &VNET_NAME(arpstat), arpstat,
118 "ARP statistics (struct arpstat, net/if_arp.h)");
120 static void arp_init(void);
121 void arprequest(struct ifnet *,
122 struct in_addr *, struct in_addr *, u_char *);
123 static void arpintr(struct mbuf *);
124 static void arptimer(void *);
126 static void in_arpinput(struct mbuf *);
129 static const struct netisr_handler arp_nh = {
131 .nh_handler = arpintr,
132 .nh_proto = NETISR_ARP,
133 .nh_policy = NETISR_POLICY_SOURCE,
137 void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
140 * called by in_ifscrub 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 CURVNET_SET(ifp->if_vnet);
154 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
155 (struct sockaddr *)&addr4);
156 IF_AFDATA_UNLOCK(ifp);
162 * Timeout routine. Age arp_tab entries periodically.
168 struct llentry *lle = (struct llentry *)arg;
171 panic("%s: NULL entry!\n", __func__);
174 ifp = lle->lle_tbl->llt_ifp;
175 CURVNET_SET(ifp->if_vnet);
178 if (lle->la_flags & LLE_STATIC)
181 if (!callout_pending(&lle->la_timer) &&
182 callout_active(&lle->la_timer)) {
183 (void) llentry_free(lle);
184 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));
196 IF_AFDATA_UNLOCK(ifp);
201 * Broadcast an ARP request. Caller specifies:
202 * - arp header source ip address
203 * - arp header target ip address
204 * - arp header source ethernet address
207 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip,
215 /* XXX don't believe this can happen (or explain why) */
217 * The caller did not supply a source address, try to find
218 * a compatible one among those assigned to this interface.
222 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
223 if (!ifa->ifa_addr ||
224 ifa->ifa_addr->sa_family != AF_INET)
226 sip = &SIN(ifa->ifa_addr)->sin_addr;
227 if (0 == ((sip->s_addr ^ tip->s_addr) &
228 SIN(ifa->ifa_netmask)->sin_addr.s_addr) )
229 break; /* found it. */
232 printf("%s: cannot find matching address\n", __func__);
237 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
239 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
240 2*ifp->if_data.ifi_addrlen;
241 m->m_pkthdr.len = m->m_len;
242 MH_ALIGN(m, m->m_len);
243 ah = mtod(m, struct arphdr *);
244 bzero((caddr_t)ah, m->m_len);
246 mac_netinet_arp_send(ifp, m);
248 ah->ar_pro = htons(ETHERTYPE_IP);
249 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
250 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
251 ah->ar_op = htons(ARPOP_REQUEST);
252 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
253 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
254 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
255 sa.sa_family = AF_ARP;
257 m->m_flags |= M_BCAST;
258 (*ifp->if_output)(ifp, m, &sa, NULL);
259 ARPSTAT_INC(txrequests);
263 * Resolve an IP address into an ethernet address.
265 * ifp is the interface we use
266 * rt0 is the route to the final destination (possibly useless)
267 * m is the mbuf. May be NULL if we don't have a packet.
268 * dst is the next hop,
269 * desten is where we want the address.
271 * On success, desten is filled in and the function returns 0;
272 * If the packet must be held pending resolution, we return EWOULDBLOCK
273 * On other errors, we return the corresponding error code.
274 * Note that m_freem() handles NULL.
277 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
278 struct sockaddr *dst, u_char *desten, struct llentry **lle)
280 struct llentry *la = 0;
286 if (m->m_flags & M_BCAST) {
289 ifp->if_broadcastaddr, ifp->if_addrlen);
292 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
294 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
301 IF_AFDATA_RLOCK(ifp);
302 la = lla_lookup(LLTABLE(ifp), flags, dst);
303 IF_AFDATA_RUNLOCK(ifp);
304 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
305 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
306 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
307 IF_AFDATA_WLOCK(ifp);
308 la = lla_lookup(LLTABLE(ifp), flags, dst);
309 IF_AFDATA_WUNLOCK(ifp);
312 if (flags & LLE_CREATE)
314 "arpresolve: can't allocate llinfo for %s\n",
315 inet_ntoa(SIN(dst)->sin_addr));
320 if ((la->la_flags & LLE_VALID) &&
321 ((la->la_flags & LLE_STATIC) || la->la_expire > time_second)) {
322 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
324 * If entry has an expiry time and it is approaching,
325 * see if we need to send an ARP request within this
326 * arpt_down interval.
328 if (!(la->la_flags & LLE_STATIC) &&
329 time_second + la->la_preempt > la->la_expire) {
330 arprequest(ifp, NULL,
331 &SIN(dst)->sin_addr, IF_LLADDR(ifp));
341 if (la->la_flags & LLE_STATIC) { /* should not happen! */
342 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
343 inet_ntoa(SIN(dst)->sin_addr));
349 renew = (la->la_asked == 0 || la->la_expire != time_second);
350 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
351 flags |= LLE_EXCLUSIVE;
356 * There is an arptab entry, but no ethernet address
357 * response yet. Replace the held mbuf with this
361 if (la->la_hold != NULL) {
362 m_freem(la->la_hold);
363 ARPSTAT_INC(dropped);
366 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
367 flags &= ~LLE_EXCLUSIVE;
373 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
374 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
375 * if we have already sent arp_maxtries ARP requests. Retransmit the
376 * ARP request, but not faster than one request per second.
378 if (la->la_asked < V_arp_maxtries)
379 error = EWOULDBLOCK; /* First request. */
381 error = rt0 != NULL && (rt0->rt_flags & RTF_GATEWAY) ?
382 EHOSTUNREACH : EHOSTDOWN;
386 la->la_expire = time_second + V_arpt_down;
387 callout_reset(&la->la_timer, hz * V_arpt_down, arptimer, la);
390 arprequest(ifp, NULL, &SIN(dst)->sin_addr,
395 if (flags & LLE_EXCLUSIVE)
403 * Common length and type checks are done here,
404 * then the protocol-specific routine is called.
407 arpintr(struct mbuf *m)
411 if (m->m_len < sizeof(struct arphdr) &&
412 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
413 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
416 ar = mtod(m, struct arphdr *);
418 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
419 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
420 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
421 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) {
422 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
423 (unsigned char *)&ar->ar_hrd, "");
428 if (m->m_len < arphdr_len(ar)) {
429 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
430 log(LOG_ERR, "arp: runt packet\n");
434 ar = mtod(m, struct arphdr *);
437 ARPSTAT_INC(received);
438 switch (ntohs(ar->ar_pro)) {
450 * ARP for Internet protocols on 10 Mb/s Ethernet.
451 * Algorithm is that given in RFC 826.
452 * In addition, a sanity check is performed on the sender
453 * protocol address, to catch impersonators.
454 * We no longer handle negotiations for use of trailer protocol:
455 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
456 * along with IP replies if we wanted trailers sent to us,
457 * and also sent them in response to IP replies.
458 * This allowed either end to announce the desire to receive
460 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
461 * but formerly didn't normally send requests.
463 static int log_arp_wrong_iface = 1;
464 static int log_arp_movements = 1;
465 static int log_arp_permanent_modify = 1;
467 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
468 &log_arp_wrong_iface, 0,
469 "log arp packets arriving on the wrong interface");
470 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
471 &log_arp_movements, 0,
472 "log arp replies from MACs different than the one in the cache");
473 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
474 &log_arp_permanent_modify, 0,
475 "log arp replies from MACs different than the one in the permanent arp entry");
479 in_arpinput(struct mbuf *m)
482 struct ifnet *ifp = m->m_pkthdr.rcvif;
483 struct llentry *la = NULL;
486 struct in_ifaddr *ia;
489 struct in_addr isaddr, itaddr, myaddr;
490 u_int8_t *enaddr = NULL;
493 int bridged = 0, is_bridge = 0;
497 struct sockaddr_in sin;
498 sin.sin_len = sizeof(struct sockaddr_in);
499 sin.sin_family = AF_INET;
500 sin.sin_addr.s_addr = 0;
504 if (ifp->if_type == IFT_BRIDGE)
507 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
508 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
509 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
513 ah = mtod(m, struct arphdr *);
514 op = ntohs(ah->ar_op);
515 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
516 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
518 if (op == ARPOP_REPLY)
519 ARPSTAT_INC(rxreplies);
522 * For a bridge, we want to check the address irrespective
523 * of the receive interface. (This will change slightly
524 * when we have clusters of interfaces).
525 * If the interface does not match, but the recieving interface
526 * is part of carp, we call carp_iamatch to see if this is a
527 * request for the virtual host ip.
528 * XXX: This is really ugly!
531 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
532 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
533 ia->ia_ifp == ifp) &&
534 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
535 ifa_ref(&ia->ia_ifa);
540 if (ifp->if_carp != NULL &&
541 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) &&
542 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
544 ifa_ref(&ia->ia_ifa);
550 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
551 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
552 ia->ia_ifp == ifp) &&
553 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
554 ifa_ref(&ia->ia_ifa);
559 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
560 (ia->ia_ifp->if_bridge == ifp->if_softc && \
561 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
562 addr == ia->ia_addr.sin_addr.s_addr)
564 * Check the case when bridge shares its MAC address with
565 * some of its children, so packets are claimed by bridge
566 * itself (bridge_input() does it first), but they are really
567 * meant to be destined to the bridge member.
570 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
571 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
572 ifa_ref(&ia->ia_ifa);
579 #undef BDG_MEMBER_MATCHES_ARP
583 * No match, use the first inet address on the receive interface
584 * as a dummy address for the rest of the function.
587 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
588 if (ifa->ifa_addr->sa_family == AF_INET) {
597 * If bridging, fall back to using any inet address.
600 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
604 ifa_ref(&ia->ia_ifa);
608 enaddr = (u_int8_t *)IF_LLADDR(ifp);
609 myaddr = ia->ia_addr.sin_addr;
610 ifa_free(&ia->ia_ifa);
611 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
612 goto drop; /* it's from me, ignore it. */
613 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
615 "arp: link address is broadcast for IP address %s!\n",
620 * Warn if another host is using the same IP address, but only if the
621 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
622 * case we suppress the warning to avoid false positive complaints of
623 * potential misconfiguration.
625 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
627 "arp: %*D is using my IP address %s on %s!\n",
628 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
629 inet_ntoa(isaddr), ifp->if_xname);
634 if (ifp->if_flags & IFF_STATICARP)
637 bzero(&sin, sizeof(sin));
638 sin.sin_len = sizeof(struct sockaddr_in);
639 sin.sin_family = AF_INET;
640 sin.sin_addr = isaddr;
641 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
642 flags |= LLE_EXCLUSIVE;
644 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
645 IF_AFDATA_UNLOCK(ifp);
647 /* the following is not an error when doing bridging */
648 if (!bridged && la->lle_tbl->llt_ifp != ifp
650 && (ifp->if_type != IFT_CARP || !carp_match)
653 if (log_arp_wrong_iface)
654 log(LOG_ERR, "arp: %s is on %s "
655 "but got reply from %*D on %s\n",
657 la->lle_tbl->llt_ifp->if_xname,
658 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
663 if ((la->la_flags & LLE_VALID) &&
664 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
665 if (la->la_flags & LLE_STATIC) {
668 "arp: %*D attempts to modify permanent "
669 "entry for %s on %s\n",
670 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
671 inet_ntoa(isaddr), ifp->if_xname);
674 if (log_arp_movements) {
675 log(LOG_INFO, "arp: %s moved from %*D "
679 (u_char *)&la->ll_addr, ":",
680 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
685 if (ifp->if_addrlen != ah->ar_hln) {
688 "arp from %*D: addr len: new %d, i/f %d (ignored)",
689 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
690 ah->ar_hln, ifp->if_addrlen);
693 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
694 la->la_flags |= LLE_VALID;
696 EVENTHANDLER_INVOKE(arp_update_event, la);
698 if (!(la->la_flags & LLE_STATIC)) {
699 la->la_expire = time_second + V_arpt_keep;
700 callout_reset(&la->la_timer, hz * V_arpt_keep,
704 la->la_preempt = V_arp_maxtries;
708 memcpy(&sa, L3_ADDR(la), sizeof(sa));
712 (*ifp->if_output)(ifp, hold, &sa, NULL);
715 if (op != ARPOP_REQUEST)
717 ARPSTAT_INC(rxrequests);
719 if (itaddr.s_addr == myaddr.s_addr) {
720 /* Shortcut.. the receiving interface is the target. */
721 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
722 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
724 struct llentry *lle = NULL;
726 sin.sin_addr = itaddr;
728 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
729 IF_AFDATA_UNLOCK(ifp);
731 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
732 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
733 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
743 sin.sin_addr = itaddr;
744 /* XXX MRT use table 0 for arp reply */
745 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
750 * Don't send proxies for nodes on the same interface
751 * as this one came out of, or we'll get into a fight
752 * over who claims what Ether address.
754 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
760 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
761 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
764 * Also check that the node which sent the ARP packet
765 * is on the the interface we expect it to be on. This
766 * avoids ARP chaos if an interface is connected to the
769 sin.sin_addr = isaddr;
771 /* XXX MRT use table 0 for arp checks */
772 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
775 if (rt->rt_ifp != ifp) {
776 log(LOG_INFO, "arp_proxy: ignoring request"
777 " from %s via %s, expecting %s\n",
778 inet_ntoa(isaddr), ifp->if_xname,
779 rt->rt_ifp->if_xname);
786 printf("arp: proxying for %s\n",
792 if (itaddr.s_addr == myaddr.s_addr &&
793 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
794 /* RFC 3927 link-local IPv4; always reply by broadcast. */
795 #ifdef DEBUG_LINKLOCAL
796 printf("arp: sending reply for link-local addr %s\n",
799 m->m_flags |= M_BCAST;
800 m->m_flags &= ~M_MCAST;
802 /* default behaviour; never reply by broadcast. */
803 m->m_flags &= ~(M_BCAST|M_MCAST);
805 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
806 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
807 ah->ar_op = htons(ARPOP_REPLY);
808 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
809 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
810 m->m_pkthdr.len = m->m_len;
811 sa.sa_family = AF_ARP;
813 (*ifp->if_output)(ifp, m, &sa, NULL);
814 ARPSTAT_INC(txreplies);
823 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
827 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
828 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
829 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
831 * interface address is considered static entry
832 * because the output of the arp utility shows
833 * that L2 entry as permanent
836 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
837 (struct sockaddr *)IA_SIN(ifa));
838 IF_AFDATA_UNLOCK(ifp);
840 log(LOG_INFO, "arp_ifinit: cannot create arp "
841 "entry for interface address\n");
845 ifa->ifa_rtrequest = NULL;
849 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
851 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
852 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
853 &IA_SIN(ifa)->sin_addr, enaddr);
854 ifa->ifa_rtrequest = NULL;
861 netisr_register(&arp_nh);
863 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);