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
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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
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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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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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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>
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 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 void arprequest(struct ifnet *,
127 struct in_addr *, struct in_addr *, u_char *);
128 static void arpintr(struct mbuf *);
129 static void arptimer(void *);
131 static void in_arpinput(struct mbuf *);
134 static const struct netisr_handler arp_nh = {
136 .nh_handler = arpintr,
137 .nh_proto = NETISR_ARP,
138 .nh_policy = NETISR_POLICY_SOURCE,
142 void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
145 * called by in_ifscrub to remove entry from the table when
146 * the interface goes away
149 arp_ifscrub(struct ifnet *ifp, uint32_t addr)
151 struct sockaddr_in addr4;
153 bzero((void *)&addr4, sizeof(addr4));
154 addr4.sin_len = sizeof(addr4);
155 addr4.sin_family = AF_INET;
156 addr4.sin_addr.s_addr = addr;
158 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
159 (struct sockaddr *)&addr4);
160 IF_AFDATA_UNLOCK(ifp);
165 * Timeout routine. Age arp_tab entries periodically.
174 KASSERT(arg != NULL, ("%s: arg NULL", __func__));
175 lle = (struct llentry *)arg;
176 ifp = lle->lle_tbl->llt_ifp;
177 CURVNET_SET(ifp->if_vnet);
180 if (lle->la_flags & LLE_STATIC)
183 if (!callout_pending(&lle->la_timer) &&
184 callout_active(&lle->la_timer)) {
185 callout_stop(&lle->la_timer);
187 pkts_dropped = llentry_free(lle);
188 ARPSTAT_ADD(dropped, pkts_dropped);
189 ARPSTAT_INC(timeouts);
192 struct sockaddr *l3addr = L3_ADDR(lle);
194 "arptimer issue: %p, IPv4 address: \"%s\"\n", lle,
196 ((const struct sockaddr_in *)l3addr)->sin_addr));
201 IF_AFDATA_UNLOCK(ifp);
206 * Broadcast an ARP request. Caller specifies:
207 * - arp header source ip address
208 * - arp header target ip address
209 * - arp header source ethernet address
212 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip,
220 /* XXX don't believe this can happen (or explain why) */
222 * The caller did not supply a source address, try to find
223 * a compatible one among those assigned to this interface.
227 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
228 if (!ifa->ifa_addr ||
229 ifa->ifa_addr->sa_family != AF_INET)
231 sip = &SIN(ifa->ifa_addr)->sin_addr;
232 if (0 == ((sip->s_addr ^ tip->s_addr) &
233 SIN(ifa->ifa_netmask)->sin_addr.s_addr) )
234 break; /* found it. */
237 printf("%s: cannot find matching address\n", __func__);
242 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
244 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
245 2*ifp->if_data.ifi_addrlen;
246 m->m_pkthdr.len = m->m_len;
247 MH_ALIGN(m, m->m_len);
248 ah = mtod(m, struct arphdr *);
249 bzero((caddr_t)ah, m->m_len);
251 mac_netinet_arp_send(ifp, m);
253 ah->ar_pro = htons(ETHERTYPE_IP);
254 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
255 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
256 ah->ar_op = htons(ARPOP_REQUEST);
257 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
258 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
259 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
260 sa.sa_family = AF_ARP;
262 m->m_flags |= M_BCAST;
263 (*ifp->if_output)(ifp, m, &sa, NULL);
264 ARPSTAT_INC(txrequests);
268 * Resolve an IP address into an ethernet address.
270 * ifp is the interface we use
271 * rt0 is the route to the final destination (possibly useless)
272 * m is the mbuf. May be NULL if we don't have a packet.
273 * dst is the next hop,
274 * desten is where we want the address.
276 * On success, desten is filled in and the function returns 0;
277 * If the packet must be held pending resolution, we return EWOULDBLOCK
278 * On other errors, we return the corresponding error code.
279 * Note that m_freem() handles NULL.
282 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
283 struct sockaddr *dst, u_char *desten, struct llentry **lle)
285 struct llentry *la = 0;
287 struct mbuf *curr = NULL;
288 struct mbuf *next = NULL;
293 if (m->m_flags & M_BCAST) {
296 ifp->if_broadcastaddr, ifp->if_addrlen);
299 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
301 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
306 IF_AFDATA_RLOCK(ifp);
307 la = lla_lookup(LLTABLE(ifp), flags, dst);
308 IF_AFDATA_RUNLOCK(ifp);
309 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
310 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
311 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
312 IF_AFDATA_WLOCK(ifp);
313 la = lla_lookup(LLTABLE(ifp), flags, dst);
314 IF_AFDATA_WUNLOCK(ifp);
317 if (flags & LLE_CREATE)
319 "arpresolve: can't allocate llinfo for %s\n",
320 inet_ntoa(SIN(dst)->sin_addr));
325 if ((la->la_flags & LLE_VALID) &&
326 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
327 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
329 * If entry has an expiry time and it is approaching,
330 * see if we need to send an ARP request within this
331 * arpt_down interval.
333 if (!(la->la_flags & LLE_STATIC) &&
334 time_uptime + la->la_preempt > la->la_expire) {
335 arprequest(ifp, NULL,
336 &SIN(dst)->sin_addr, IF_LLADDR(ifp));
346 if (la->la_flags & LLE_STATIC) { /* should not happen! */
347 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
348 inet_ntoa(SIN(dst)->sin_addr));
354 renew = (la->la_asked == 0 || la->la_expire != time_uptime);
355 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
356 flags |= LLE_EXCLUSIVE;
361 * There is an arptab entry, but no ethernet address
362 * response yet. Add the mbuf to the list, dropping
363 * the oldest packet if we have exceeded the system
367 if (la->la_numheld >= V_arp_maxhold) {
368 if (la->la_hold != NULL) {
369 next = la->la_hold->m_nextpkt;
370 m_freem(la->la_hold);
373 ARPSTAT_INC(dropped);
376 if (la->la_hold != NULL) {
378 while (curr->m_nextpkt != NULL)
379 curr = curr->m_nextpkt;
384 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
385 flags &= ~LLE_EXCLUSIVE;
391 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
392 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
393 * if we have already sent arp_maxtries ARP requests. Retransmit the
394 * ARP request, but not faster than one request per second.
396 if (la->la_asked < V_arp_maxtries)
397 error = EWOULDBLOCK; /* First request. */
399 error = rt0 != NULL && (rt0->rt_flags & RTF_GATEWAY) ?
400 EHOSTUNREACH : EHOSTDOWN;
406 la->la_expire = time_uptime;
407 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
413 arprequest(ifp, NULL, &SIN(dst)->sin_addr,
418 if (flags & LLE_EXCLUSIVE)
426 * Common length and type checks are done here,
427 * then the protocol-specific routine is called.
430 arpintr(struct mbuf *m)
434 if (m->m_len < sizeof(struct arphdr) &&
435 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
436 log(LOG_NOTICE, "arp: runt packet -- m_pullup failed\n");
439 ar = mtod(m, struct arphdr *);
441 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
442 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
443 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
444 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394 &&
445 ntohs(ar->ar_hrd) != ARPHRD_INFINIBAND) {
446 log(LOG_NOTICE, "arp: unknown hardware address format (0x%2D)"
447 " (from %*D to %*D)\n", (unsigned char *)&ar->ar_hrd, "",
448 ETHER_ADDR_LEN, (u_char *)ar_sha(ar), ":",
449 ETHER_ADDR_LEN, (u_char *)ar_tha(ar), ":");
454 if (m->m_len < arphdr_len(ar)) {
455 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
456 log(LOG_NOTICE, "arp: runt packet\n");
460 ar = mtod(m, struct arphdr *);
463 ARPSTAT_INC(received);
464 switch (ntohs(ar->ar_pro)) {
476 * ARP for Internet protocols on 10 Mb/s Ethernet.
477 * Algorithm is that given in RFC 826.
478 * In addition, a sanity check is performed on the sender
479 * protocol address, to catch impersonators.
480 * We no longer handle negotiations for use of trailer protocol:
481 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
482 * along with IP replies if we wanted trailers sent to us,
483 * and also sent them in response to IP replies.
484 * This allowed either end to announce the desire to receive
486 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
487 * but formerly didn't normally send requests.
489 static int log_arp_wrong_iface = 1;
490 static int log_arp_movements = 1;
491 static int log_arp_permanent_modify = 1;
493 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
494 &log_arp_wrong_iface, 0,
495 "log arp packets arriving on the wrong interface");
496 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
497 &log_arp_movements, 0,
498 "log arp replies from MACs different than the one in the cache");
499 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
500 &log_arp_permanent_modify, 0,
501 "log arp replies from MACs different than the one in the permanent arp entry");
505 in_arpinput(struct mbuf *m)
508 struct ifnet *ifp = m->m_pkthdr.rcvif;
509 struct llentry *la = NULL;
512 struct in_ifaddr *ia;
514 struct in_addr isaddr, itaddr, myaddr;
515 u_int8_t *enaddr = NULL;
518 int bridged = 0, is_bridge = 0;
520 struct sockaddr_in sin;
521 sin.sin_len = sizeof(struct sockaddr_in);
522 sin.sin_family = AF_INET;
523 sin.sin_addr.s_addr = 0;
527 if (ifp->if_type == IFT_BRIDGE)
530 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
531 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
532 log(LOG_NOTICE, "in_arp: runt packet -- m_pullup failed\n");
536 ah = mtod(m, struct arphdr *);
538 * ARP is only for IPv4 so we can reject packets with
539 * a protocol length not equal to an IPv4 address.
541 if (ah->ar_pln != sizeof(struct in_addr)) {
542 log(LOG_NOTICE, "in_arp: requested protocol length != %zu\n",
543 sizeof(struct in_addr));
547 if (ETHER_IS_MULTICAST(ar_sha(ah))) {
548 log(LOG_NOTICE, "in_arp: %*D is multicast\n",
549 ifp->if_addrlen, (u_char *)ar_sha(ah), ":");
553 op = ntohs(ah->ar_op);
554 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
555 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
557 if (op == ARPOP_REPLY)
558 ARPSTAT_INC(rxreplies);
561 * For a bridge, we want to check the address irrespective
562 * of the receive interface. (This will change slightly
563 * when we have clusters of interfaces).
564 * If the interface does not match, but the recieving interface
565 * is part of carp, we call carp_iamatch to see if this is a
566 * request for the virtual host ip.
567 * XXX: This is really ugly!
570 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
571 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
572 ia->ia_ifp == ifp) &&
573 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
574 ifa_ref(&ia->ia_ifa);
578 if (ifp->if_carp != NULL &&
579 (*carp_iamatch_p)(ifp, ia, &isaddr, &enaddr) &&
580 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
582 ifa_ref(&ia->ia_ifa);
587 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
588 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
589 ia->ia_ifp == ifp) &&
590 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
591 ifa_ref(&ia->ia_ifa);
596 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
597 (ia->ia_ifp->if_bridge == ifp->if_softc && \
598 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
599 addr == ia->ia_addr.sin_addr.s_addr)
601 * Check the case when bridge shares its MAC address with
602 * some of its children, so packets are claimed by bridge
603 * itself (bridge_input() does it first), but they are really
604 * meant to be destined to the bridge member.
607 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
608 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
609 ifa_ref(&ia->ia_ifa);
616 #undef BDG_MEMBER_MATCHES_ARP
620 * No match, use the first inet address on the receive interface
621 * as a dummy address for the rest of the function.
624 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
625 if (ifa->ifa_addr->sa_family == AF_INET) {
628 IF_ADDR_RUNLOCK(ifp);
631 IF_ADDR_RUNLOCK(ifp);
634 * If bridging, fall back to using any inet address.
637 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
641 ifa_ref(&ia->ia_ifa);
645 enaddr = (u_int8_t *)IF_LLADDR(ifp);
646 myaddr = ia->ia_addr.sin_addr;
647 ifa_free(&ia->ia_ifa);
648 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
649 goto drop; /* it's from me, ignore it. */
650 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
652 "arp: link address is broadcast for IP address %s!\n",
657 * Warn if another host is using the same IP address, but only if the
658 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
659 * case we suppress the warning to avoid false positive complaints of
660 * potential misconfiguration.
662 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
664 "arp: %*D is using my IP address %s on %s!\n",
665 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
666 inet_ntoa(isaddr), ifp->if_xname);
671 if (ifp->if_flags & IFF_STATICARP)
674 bzero(&sin, sizeof(sin));
675 sin.sin_len = sizeof(struct sockaddr_in);
676 sin.sin_family = AF_INET;
677 sin.sin_addr = isaddr;
678 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
679 flags |= LLE_EXCLUSIVE;
681 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
682 IF_AFDATA_UNLOCK(ifp);
684 /* the following is not an error when doing bridging */
685 if (!bridged && la->lle_tbl->llt_ifp != ifp && !carp_match) {
686 if (log_arp_wrong_iface)
687 log(LOG_WARNING, "arp: %s is on %s "
688 "but got reply from %*D on %s\n",
690 la->lle_tbl->llt_ifp->if_xname,
691 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
696 if ((la->la_flags & LLE_VALID) &&
697 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
698 if (la->la_flags & LLE_STATIC) {
700 if (log_arp_permanent_modify)
702 "arp: %*D attempts to modify "
703 "permanent entry for %s on %s\n",
705 (u_char *)ar_sha(ah), ":",
706 inet_ntoa(isaddr), ifp->if_xname);
709 if (log_arp_movements) {
710 log(LOG_INFO, "arp: %s moved from %*D "
714 (u_char *)&la->ll_addr, ":",
715 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
720 if (ifp->if_addrlen != ah->ar_hln) {
722 log(LOG_WARNING, "arp from %*D: addr len: new %d, "
723 "i/f %d (ignored)\n", ifp->if_addrlen,
724 (u_char *) ar_sha(ah), ":", ah->ar_hln,
728 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
729 la->la_flags |= LLE_VALID;
731 EVENTHANDLER_INVOKE(arp_update_event, la);
733 if (!(la->la_flags & LLE_STATIC)) {
737 la->la_expire = time_uptime + V_arpt_keep;
738 canceled = callout_reset(&la->la_timer,
739 hz * V_arpt_keep, arptimer, la);
744 la->la_preempt = V_arp_maxtries;
746 * The packets are all freed within the call to the output
749 * NB: The lock MUST be released before the call to the
752 if (la->la_hold != NULL) {
753 struct mbuf *m_hold, *m_hold_next;
755 m_hold = la->la_hold;
758 memcpy(&sa, L3_ADDR(la), sizeof(sa));
760 for (; m_hold != NULL; m_hold = m_hold_next) {
761 m_hold_next = m_hold->m_nextpkt;
762 m_hold->m_nextpkt = NULL;
763 (*ifp->if_output)(ifp, m_hold, &sa, NULL);
769 if (op != ARPOP_REQUEST)
771 ARPSTAT_INC(rxrequests);
773 if (itaddr.s_addr == myaddr.s_addr) {
774 /* Shortcut.. the receiving interface is the target. */
775 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
776 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
778 struct llentry *lle = NULL;
780 sin.sin_addr = itaddr;
782 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
783 IF_AFDATA_UNLOCK(ifp);
785 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
786 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
787 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
797 sin.sin_addr = itaddr;
798 /* XXX MRT use table 0 for arp reply */
799 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
804 * Don't send proxies for nodes on the same interface
805 * as this one came out of, or we'll get into a fight
806 * over who claims what Ether address.
808 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
814 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
815 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
818 * Also check that the node which sent the ARP packet
819 * is on the interface we expect it to be on. This
820 * avoids ARP chaos if an interface is connected to the
823 sin.sin_addr = isaddr;
825 /* XXX MRT use table 0 for arp checks */
826 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
829 if (rt->rt_ifp != ifp) {
830 log(LOG_INFO, "arp_proxy: ignoring request"
831 " from %s via %s, expecting %s\n",
832 inet_ntoa(isaddr), ifp->if_xname,
833 rt->rt_ifp->if_xname);
840 printf("arp: proxying for %s\n",
846 if (itaddr.s_addr == myaddr.s_addr &&
847 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
848 /* RFC 3927 link-local IPv4; always reply by broadcast. */
849 #ifdef DEBUG_LINKLOCAL
850 printf("arp: sending reply for link-local addr %s\n",
853 m->m_flags |= M_BCAST;
854 m->m_flags &= ~M_MCAST;
856 /* default behaviour; never reply by broadcast. */
857 m->m_flags &= ~(M_BCAST|M_MCAST);
859 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
860 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
861 ah->ar_op = htons(ARPOP_REPLY);
862 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
863 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
864 m->m_pkthdr.len = m->m_len;
865 m->m_pkthdr.rcvif = NULL;
866 sa.sa_family = AF_ARP;
868 (*ifp->if_output)(ifp, m, &sa, NULL);
869 ARPSTAT_INC(txreplies);
878 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
882 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
883 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
884 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
886 * interface address is considered static entry
887 * because the output of the arp utility shows
888 * that L2 entry as permanent
891 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
892 (struct sockaddr *)IA_SIN(ifa));
893 IF_AFDATA_UNLOCK(ifp);
895 log(LOG_INFO, "arp_ifinit: cannot create arp "
896 "entry for interface address\n");
900 ifa->ifa_rtrequest = NULL;
904 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
906 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
907 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
908 &IA_SIN(ifa)->sin_addr, enaddr);
909 ifa->ifa_rtrequest = NULL;
916 netisr_register(&arp_nh);
918 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);