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, "");
86 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
88 static VNET_DEFINE(int, arp_maxtries) = 5;
89 VNET_DEFINE(int, useloopback) = 1; /* use loopback interface for
91 static VNET_DEFINE(int, arp_proxyall) = 0;
92 static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for
94 static VNET_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
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)
102 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
103 &VNET_NAME(arpt_keep), 0,
104 "ARP entry lifetime in seconds");
105 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
106 &VNET_NAME(arp_maxtries), 0,
107 "ARP resolution attempts before returning error");
108 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
109 &VNET_NAME(useloopback), 0,
110 "Use the loopback interface for local traffic");
111 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
112 &VNET_NAME(arp_proxyall), 0,
113 "Enable proxy ARP for all suitable requests");
114 SYSCTL_VNET_STRUCT(_net_link_ether_arp, OID_AUTO, stats, CTLFLAG_RW,
115 &VNET_NAME(arpstat), arpstat,
116 "ARP statistics (struct arpstat, net/if_arp.h)");
118 static void arp_init(void);
119 void arprequest(struct ifnet *,
120 struct in_addr *, struct in_addr *, u_char *);
121 static void arpintr(struct mbuf *);
122 static void arptimer(void *);
124 static void in_arpinput(struct mbuf *);
127 static const struct netisr_handler arp_nh = {
129 .nh_handler = arpintr,
130 .nh_proto = NETISR_ARP,
131 .nh_policy = NETISR_POLICY_SOURCE,
135 void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
138 * called by in_ifscrub to remove entry from the table when
139 * the interface goes away
142 arp_ifscrub(struct ifnet *ifp, uint32_t addr)
144 struct sockaddr_in addr4;
146 bzero((void *)&addr4, sizeof(addr4));
147 addr4.sin_len = sizeof(addr4);
148 addr4.sin_family = AF_INET;
149 addr4.sin_addr.s_addr = addr;
150 CURVNET_SET(ifp->if_vnet);
152 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
153 (struct sockaddr *)&addr4);
154 IF_AFDATA_UNLOCK(ifp);
160 * Timeout routine. Age arp_tab entries periodically.
166 struct llentry *lle = (struct llentry *)arg;
169 panic("%s: NULL entry!\n", __func__);
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 (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;
388 la->la_expire = time_second + V_arpt_down;
389 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
395 arprequest(ifp, NULL, &SIN(dst)->sin_addr,
400 if (flags & LLE_EXCLUSIVE)
408 * Common length and type checks are done here,
409 * then the protocol-specific routine is called.
412 arpintr(struct mbuf *m)
416 if (m->m_len < sizeof(struct arphdr) &&
417 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
418 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
421 ar = mtod(m, struct arphdr *);
423 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
424 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
425 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
426 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) {
427 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
428 (unsigned char *)&ar->ar_hrd, "");
433 if (m->m_len < arphdr_len(ar)) {
434 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
435 log(LOG_ERR, "arp: runt packet\n");
439 ar = mtod(m, struct arphdr *);
442 ARPSTAT_INC(received);
443 switch (ntohs(ar->ar_pro)) {
455 * ARP for Internet protocols on 10 Mb/s Ethernet.
456 * Algorithm is that given in RFC 826.
457 * In addition, a sanity check is performed on the sender
458 * protocol address, to catch impersonators.
459 * We no longer handle negotiations for use of trailer protocol:
460 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
461 * along with IP replies if we wanted trailers sent to us,
462 * and also sent them in response to IP replies.
463 * This allowed either end to announce the desire to receive
465 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
466 * but formerly didn't normally send requests.
468 static int log_arp_wrong_iface = 1;
469 static int log_arp_movements = 1;
470 static int log_arp_permanent_modify = 1;
472 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
473 &log_arp_wrong_iface, 0,
474 "log arp packets arriving on the wrong interface");
475 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
476 &log_arp_movements, 0,
477 "log arp replies from MACs different than the one in the cache");
478 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
479 &log_arp_permanent_modify, 0,
480 "log arp replies from MACs different than the one in the permanent arp entry");
484 in_arpinput(struct mbuf *m)
487 struct ifnet *ifp = m->m_pkthdr.rcvif;
488 struct llentry *la = NULL;
491 struct in_ifaddr *ia;
494 struct in_addr isaddr, itaddr, myaddr;
495 u_int8_t *enaddr = NULL;
498 int bridged = 0, is_bridge = 0;
502 struct sockaddr_in sin;
503 sin.sin_len = sizeof(struct sockaddr_in);
504 sin.sin_family = AF_INET;
505 sin.sin_addr.s_addr = 0;
509 if (ifp->if_type == IFT_BRIDGE)
512 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
513 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
514 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
518 ah = mtod(m, struct arphdr *);
519 op = ntohs(ah->ar_op);
520 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
521 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
523 if (op == ARPOP_REPLY)
524 ARPSTAT_INC(rxreplies);
527 * For a bridge, we want to check the address irrespective
528 * of the receive interface. (This will change slightly
529 * when we have clusters of interfaces).
530 * If the interface does not match, but the recieving interface
531 * is part of carp, we call carp_iamatch to see if this is a
532 * request for the virtual host ip.
533 * XXX: This is really ugly!
536 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
537 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
538 ia->ia_ifp == ifp) &&
539 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
540 ifa_ref(&ia->ia_ifa);
545 if (ifp->if_carp != NULL &&
546 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) &&
547 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
549 ifa_ref(&ia->ia_ifa);
555 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
556 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
557 ia->ia_ifp == ifp) &&
558 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
559 ifa_ref(&ia->ia_ifa);
564 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
565 (ia->ia_ifp->if_bridge == ifp->if_softc && \
566 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
567 addr == ia->ia_addr.sin_addr.s_addr)
569 * Check the case when bridge shares its MAC address with
570 * some of its children, so packets are claimed by bridge
571 * itself (bridge_input() does it first), but they are really
572 * meant to be destined to the bridge member.
575 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
576 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
577 ifa_ref(&ia->ia_ifa);
584 #undef BDG_MEMBER_MATCHES_ARP
588 * No match, use the first inet address on the receive interface
589 * as a dummy address for the rest of the function.
592 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
593 if (ifa->ifa_addr->sa_family == AF_INET) {
602 * If bridging, fall back to using any inet address.
605 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
609 ifa_ref(&ia->ia_ifa);
613 enaddr = (u_int8_t *)IF_LLADDR(ifp);
614 myaddr = ia->ia_addr.sin_addr;
615 ifa_free(&ia->ia_ifa);
616 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
617 goto drop; /* it's from me, ignore it. */
618 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
620 "arp: link address is broadcast for IP address %s!\n",
625 * Warn if another host is using the same IP address, but only if the
626 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
627 * case we suppress the warning to avoid false positive complaints of
628 * potential misconfiguration.
630 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
632 "arp: %*D is using my IP address %s on %s!\n",
633 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
634 inet_ntoa(isaddr), ifp->if_xname);
639 if (ifp->if_flags & IFF_STATICARP)
642 bzero(&sin, sizeof(sin));
643 sin.sin_len = sizeof(struct sockaddr_in);
644 sin.sin_family = AF_INET;
645 sin.sin_addr = isaddr;
646 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
647 flags |= LLE_EXCLUSIVE;
649 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
650 IF_AFDATA_UNLOCK(ifp);
652 /* the following is not an error when doing bridging */
653 if (!bridged && la->lle_tbl->llt_ifp != ifp
655 && (ifp->if_type != IFT_CARP || !carp_match)
658 if (log_arp_wrong_iface)
659 log(LOG_ERR, "arp: %s is on %s "
660 "but got reply from %*D on %s\n",
662 la->lle_tbl->llt_ifp->if_xname,
663 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
668 if ((la->la_flags & LLE_VALID) &&
669 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
670 if (la->la_flags & LLE_STATIC) {
673 "arp: %*D attempts to modify permanent "
674 "entry for %s on %s\n",
675 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
676 inet_ntoa(isaddr), ifp->if_xname);
679 if (log_arp_movements) {
680 log(LOG_INFO, "arp: %s moved from %*D "
684 (u_char *)&la->ll_addr, ":",
685 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
690 if (ifp->if_addrlen != ah->ar_hln) {
693 "arp from %*D: addr len: new %d, i/f %d (ignored)",
694 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
695 ah->ar_hln, ifp->if_addrlen);
698 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
699 la->la_flags |= LLE_VALID;
701 if (!(la->la_flags & LLE_STATIC)) {
705 la->la_expire = time_second + V_arpt_keep;
706 canceled = callout_reset(&la->la_timer,
707 hz * V_arpt_keep, arptimer, la);
712 la->la_preempt = V_arp_maxtries;
716 memcpy(&sa, L3_ADDR(la), sizeof(sa));
720 (*ifp->if_output)(ifp, hold, &sa, NULL);
723 if (op != ARPOP_REQUEST)
725 ARPSTAT_INC(rxrequests);
727 if (itaddr.s_addr == myaddr.s_addr) {
728 /* Shortcut.. the receiving interface is the target. */
729 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
730 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
732 struct llentry *lle = NULL;
734 sin.sin_addr = itaddr;
736 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
737 IF_AFDATA_UNLOCK(ifp);
739 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
740 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
741 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
751 sin.sin_addr = itaddr;
752 /* XXX MRT use table 0 for arp reply */
753 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
758 * Don't send proxies for nodes on the same interface
759 * as this one came out of, or we'll get into a fight
760 * over who claims what Ether address.
762 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
768 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
769 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
772 * Also check that the node which sent the ARP packet
773 * is on the the interface we expect it to be on. This
774 * avoids ARP chaos if an interface is connected to the
777 sin.sin_addr = isaddr;
779 /* XXX MRT use table 0 for arp checks */
780 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
783 if (rt->rt_ifp != ifp) {
784 log(LOG_INFO, "arp_proxy: ignoring request"
785 " from %s via %s, expecting %s\n",
786 inet_ntoa(isaddr), ifp->if_xname,
787 rt->rt_ifp->if_xname);
794 printf("arp: proxying for %s\n",
800 if (itaddr.s_addr == myaddr.s_addr &&
801 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
802 /* RFC 3927 link-local IPv4; always reply by broadcast. */
803 #ifdef DEBUG_LINKLOCAL
804 printf("arp: sending reply for link-local addr %s\n",
807 m->m_flags |= M_BCAST;
808 m->m_flags &= ~M_MCAST;
810 /* default behaviour; never reply by broadcast. */
811 m->m_flags &= ~(M_BCAST|M_MCAST);
813 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
814 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
815 ah->ar_op = htons(ARPOP_REPLY);
816 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
817 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
818 m->m_pkthdr.len = m->m_len;
819 sa.sa_family = AF_ARP;
821 (*ifp->if_output)(ifp, m, &sa, NULL);
822 ARPSTAT_INC(txreplies);
831 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
835 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
836 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
837 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
839 * interface address is considered static entry
840 * because the output of the arp utility shows
841 * that L2 entry as permanent
844 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
845 (struct sockaddr *)IA_SIN(ifa));
846 IF_AFDATA_UNLOCK(ifp);
848 log(LOG_INFO, "arp_ifinit: cannot create arp "
849 "entry for interface address\n");
853 ifa->ifa_rtrequest = NULL;
857 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
859 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
860 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
861 &IA_SIN(ifa)->sin_addr, enaddr);
862 ifa->ifa_rtrequest = NULL;
869 netisr_register(&arp_nh);
871 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);