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4 * This code is derived from software contributed to The DragonFly Project
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61 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93
62 * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $
66 * Ethernet address resolution protocol.
68 * add "inuse/lock" bit (or ref. count) along with valid bit
74 #include <sys/param.h>
75 #include <sys/kernel.h>
76 #include <sys/queue.h>
77 #include <sys/sysctl.h>
78 #include <sys/systm.h>
80 #include <sys/malloc.h>
81 #include <sys/socket.h>
82 #include <sys/syslog.h>
86 #include <net/if_dl.h>
87 #include <net/if_types.h>
88 #include <net/route.h>
89 #include <net/netisr.h>
90 #include <net/if_llc.h>
92 #include <netinet/in.h>
93 #include <netinet/in_var.h>
94 #include <netinet/if_ether.h>
96 #include <sys/thread2.h>
97 #include <sys/msgport2.h>
98 #include <net/netmsg2.h>
99 #include <net/netisr2.h>
100 #include <sys/mplock2.h>
103 #include <netinet/ip_carp.h>
106 #define SIN(s) ((struct sockaddr_in *)s)
107 #define SDL(s) ((struct sockaddr_dl *)s)
109 SYSCTL_DECL(_net_link_ether);
110 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
113 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */
114 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
115 static int arpt_down = 20; /* once declared down, don't send for 20 sec */
117 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
119 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
121 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
124 #define rt_expire rt_rmx.rmx_expire
127 LIST_ENTRY(llinfo_arp) la_le;
128 struct rtentry *la_rt;
129 struct mbuf *la_hold; /* last packet until resolved/timeout */
130 u_short la_preempt; /* countdown for pre-expiry arps */
131 u_short la_asked; /* #times we QUERIED following expiration */
134 static int arp_maxtries = 5;
135 static int useloopback = 1; /* use loopback interface for local traffic */
136 static int arp_proxyall = 0;
137 static int arp_refresh = 60; /* refresh arp cache ~60 (not impl yet) */
138 static int arp_restricted_match = 0;
139 static int arp_ignore_probes = 1;
141 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
142 &arp_maxtries, 0, "ARP resolution attempts before returning error");
143 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
144 &useloopback, 0, "Use the loopback interface for local traffic");
145 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
146 &arp_proxyall, 0, "Enable proxy ARP for all suitable requests");
147 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, restricted_match, CTLFLAG_RW,
148 &arp_restricted_match, 0, "Only match against the sender");
149 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, refresh, CTLFLAG_RW,
150 &arp_refresh, 0, "Preemptively refresh the ARP");
151 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, ignore_probes, CTLFLAG_RW,
152 &arp_ignore_probes, 0, "Ignore ARP probes");
154 static void arp_rtrequest(int, struct rtentry *);
155 static void arprequest(struct ifnet *, const struct in_addr *,
156 const struct in_addr *, const u_char *);
157 static void arprequest_async(struct ifnet *, const struct in_addr *,
158 const struct in_addr *, const u_char *);
159 static void arpintr(netmsg_t msg);
160 static void arptfree(struct llinfo_arp *);
161 static void arptimer(void *);
162 static struct llinfo_arp *
163 arplookup(in_addr_t, boolean_t, boolean_t, boolean_t);
165 static void in_arpinput(struct mbuf *);
166 static void in_arpreply(struct mbuf *m, in_addr_t, in_addr_t);
167 static void arp_update_msghandler(netmsg_t);
168 static void arp_reply_msghandler(netmsg_t);
171 struct arp_pcpu_data {
172 struct callout timer_ch;
173 struct netmsg_base timer_nmsg;
174 LIST_HEAD(, llinfo_arp) llinfo_list;
177 static struct arp_pcpu_data arp_data[MAXCPU];
180 * Timeout routine. Age arp_tab entries periodically.
183 arptimer_dispatch(netmsg_t nmsg)
185 struct llinfo_arp *la, *nla;
186 struct arp_pcpu_data *ad = &arp_data[mycpuid];
190 lwkt_replymsg(&nmsg->lmsg, 0);
193 LIST_FOREACH_MUTABLE(la, &ad->llinfo_list, la_le, nla) {
194 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_uptime)
197 callout_reset(&ad->timer_ch, arpt_prune * hz, arptimer, NULL);
201 arptimer(void *arg __unused)
204 struct lwkt_msg *lmsg = &arp_data[cpuid].timer_nmsg.lmsg;
207 if (lmsg->ms_flags & MSGF_DONE)
208 lwkt_sendmsg_oncpu(netisr_cpuport(cpuid), lmsg);
213 * Parallel to llc_rtrequest.
215 * Called after a route is successfully added to the tree to fix-up the
216 * route and initiate arp operations if required.
219 arp_rtrequest(int req, struct rtentry *rt)
221 struct sockaddr *gate = rt->rt_gateway;
222 struct llinfo_arp *la = rt->rt_llinfo;
224 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK };
226 if (rt->rt_flags & RTF_GATEWAY)
232 * XXX: If this is a manually added route to interface
233 * such as older version of routed or gated might provide,
234 * restore cloning bit.
236 if (!(rt->rt_flags & RTF_HOST) &&
237 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
238 rt->rt_flags |= RTF_CLONING;
239 if (rt->rt_flags & RTF_CLONING) {
241 * Case 1: This route should come from a route to iface.
243 rt_setgate(rt, rt_key(rt),
244 (struct sockaddr *)&null_sdl,
246 gate = rt->rt_gateway;
247 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
248 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
249 rt->rt_expire = time_uptime;
253 * Announce a new entry if requested, and only announce it
256 if ((rt->rt_flags & RTF_ANNOUNCE) && mycpuid == 0) {
257 arprequest_async(rt->rt_ifp,
258 &SIN(rt_key(rt))->sin_addr,
259 &SIN(rt_key(rt))->sin_addr,
264 if (gate->sa_family != AF_LINK ||
265 gate->sa_len < sizeof(struct sockaddr_dl)) {
266 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
269 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
270 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
272 break; /* This happens on a route change */
274 * Case 2: This route may come from cloning, or a manual route
275 * add with a LL address.
277 R_Malloc(la, struct llinfo_arp *, sizeof *la);
280 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
283 bzero(la, sizeof *la);
285 rt->rt_flags |= RTF_LLINFO;
286 LIST_INSERT_HEAD(&arp_data[mycpuid].llinfo_list, la, la_le);
290 * This keeps the multicast addresses from showing up
291 * in `arp -a' listings as unresolved. It's not actually
292 * functional. Then the same for broadcast.
294 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) {
295 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
297 SDL(gate)->sdl_alen = 6;
300 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) {
301 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr,
302 rt->rt_ifp->if_addrlen);
303 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen;
309 * This fixes up the routing interface for local addresses.
310 * The route is adjusted to point at lo0 and the expiration
313 * NOTE: This prevents locally targetted traffic from going
314 * out the hardware interface, which is inefficient
315 * and might not work if the hardware cannot listen
316 * to its own transmitted packets. Setting
317 * net.link.ether.inet.useloopback to 0 will force
318 * packets for local addresses out the hardware (and
319 * it is expected to receive its own packet).
321 * XXX We should just be able to test RTF_LOCAL here instead
322 * of having to compare IPs.
324 if (SIN(rt_key(rt))->sin_addr.s_addr ==
325 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
327 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)),
328 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen);
337 LIST_REMOVE(la, la_le);
338 rt->rt_llinfo = NULL;
339 rt->rt_flags &= ~RTF_LLINFO;
340 if (la->la_hold != NULL)
341 m_freem(la->la_hold);
348 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip,
349 const struct in_addr *tip, const u_char *enaddr)
355 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL)
357 m->m_pkthdr.rcvif = NULL;
359 switch (ifp->if_type) {
362 * This may not be correct for types not explicitly
363 * listed, but this is our best guess
366 ar_hrd = htons(ARPHRD_ETHER);
368 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
369 m->m_pkthdr.len = m->m_len;
370 MH_ALIGN(m, m->m_len);
372 ah = mtod(m, struct arphdr *);
377 ah->ar_pro = htons(ETHERTYPE_IP);
378 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
379 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
380 ah->ar_op = htons(ARPOP_REQUEST);
381 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
382 memset(ar_tha(ah), 0, ah->ar_hln);
383 memcpy(ar_spa(ah), sip, ah->ar_pln);
384 memcpy(ar_tpa(ah), tip, ah->ar_pln);
390 arpreq_send(struct ifnet *ifp, struct mbuf *m)
393 struct ether_header *eh;
395 switch (ifp->if_type) {
398 * This may not be correct for types not explicitly
399 * listed, but this is our best guess
402 eh = (struct ether_header *)sa.sa_data;
403 /* if_output() will not swap */
404 eh->ether_type = htons(ETHERTYPE_ARP);
405 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen);
409 sa.sa_family = AF_UNSPEC;
410 sa.sa_len = sizeof(sa);
411 ifp->if_output(ifp, m, &sa, NULL);
415 arpreq_send_handler(netmsg_t msg)
417 struct mbuf *m = msg->packet.nm_packet;
418 struct ifnet *ifp = msg->lmsg.u.ms_resultp;
421 /* nmsg was embedded in the mbuf, do not reply! */
425 * Broadcast an ARP request. Caller specifies:
426 * - arp header source ip address
427 * - arp header target ip address
428 * - arp header source ethernet address
430 * NOTE: Caller MUST NOT hold ifp's serializer
433 arprequest(struct ifnet *ifp, const struct in_addr *sip,
434 const struct in_addr *tip, const u_char *enaddr)
438 if (enaddr == NULL) {
439 if (ifp->if_bridge) {
440 enaddr = IF_LLADDR(ether_bridge_interface(ifp));
442 enaddr = IF_LLADDR(ifp);
446 m = arpreq_alloc(ifp, sip, tip, enaddr);
453 * Same as arprequest(), except:
454 * - Caller is allowed to hold ifp's serializer
455 * - Network output is done in protocol thead
458 arprequest_async(struct ifnet *ifp, const struct in_addr *sip,
459 const struct in_addr *tip, const u_char *enaddr)
462 struct netmsg_packet *pmsg;
464 if (enaddr == NULL) {
465 if (ifp->if_bridge) {
466 enaddr = IF_LLADDR(ether_bridge_interface(ifp));
468 enaddr = IF_LLADDR(ifp);
471 m = arpreq_alloc(ifp, sip, tip, enaddr);
475 pmsg = &m->m_hdr.mh_netmsg;
476 netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport,
477 0, arpreq_send_handler);
479 pmsg->base.lmsg.u.ms_resultp = ifp;
481 lwkt_sendmsg_oncpu(netisr_cpuport(mycpuid), &pmsg->base.lmsg);
485 * Resolve an IP address into an ethernet address. If success,
486 * desten is filled in. If there is no entry in arptab,
487 * set one up and broadcast a request for the IP address.
488 * Hold onto this mbuf and resend it once the address
489 * is finally resolved. A return value of 1 indicates
490 * that desten has been filled in and the packet should be sent
491 * normally; a 0 return indicates that the packet has been
492 * taken over here, either now or for later transmission.
495 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
496 struct sockaddr *dst, u_char *desten)
498 struct rtentry *rt = NULL;
499 struct llinfo_arp *la = NULL;
500 struct sockaddr_dl *sdl;
502 if (m->m_flags & M_BCAST) { /* broadcast */
503 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen);
506 if (m->m_flags & M_MCAST) {/* multicast */
507 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
511 if (rt_llroute(dst, rt0, &rt) != 0) {
518 la = arplookup(SIN(dst)->sin_addr.s_addr,
519 TRUE, RTL_REPORTMSG, FALSE);
523 if (la == NULL || rt == NULL) {
524 char addr[INET_ADDRSTRLEN];
526 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n",
527 kinet_ntoa(SIN(dst)->sin_addr, addr), la ? "la" : " ",
532 sdl = SDL(rt->rt_gateway);
534 * Check the address family and length is valid, the address
535 * is resolved; otherwise, try to resolve.
537 if ((rt->rt_expire == 0 || rt->rt_expire > time_uptime) &&
538 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
540 * If entry has an expiry time and it is approaching,
541 * see if we need to send an ARP request within this
542 * arpt_down interval.
544 if ((rt->rt_expire != 0) &&
545 (time_uptime + la->la_preempt > rt->rt_expire)) {
547 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
553 bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
557 * If ARP is disabled or static on this interface, stop.
559 * Probably should not allocate empty llinfo struct if we are
560 * not going to be sending out an arp request.
562 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) {
567 * There is an arptab entry, but no ethernet address
568 * response yet. Replace the held mbuf with this
571 if (la->la_hold != NULL)
572 m_freem(la->la_hold);
574 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) {
575 rt->rt_flags &= ~RTF_REJECT;
576 if (la->la_asked == 0 || rt->rt_expire != time_uptime) {
577 rt->rt_expire = time_uptime;
578 if (la->la_asked++ < arp_maxtries) {
580 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
584 rt->rt_flags |= RTF_REJECT;
585 rt->rt_expire += arpt_down;
587 la->la_preempt = arp_maxtries;
595 * Common length and type checks are done here,
596 * then the protocol-specific routine is called.
599 arpintr(netmsg_t msg)
601 struct mbuf *m = msg->packet.nm_packet;
606 if (m->m_len < sizeof(struct arphdr) &&
607 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) {
608 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
611 ar = mtod(m, struct arphdr *);
613 ar_hrd = ntohs(ar->ar_hrd);
614 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) {
615 hexncpy((unsigned char *)&ar->ar_hrd, 2, hexstr, 5, NULL);
616 log(LOG_ERR, "arp: unknown hardware address format (0x%s)\n",
622 if (m->m_pkthdr.len < arphdr_len(ar)) {
623 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
624 log(LOG_ERR, "arp: runt packet\n");
627 ar = mtod(m, struct arphdr *);
630 switch (ntohs(ar->ar_pro)) {
638 /* msg was embedded in the mbuf, do not reply! */
643 * ARP for Internet protocols on 10 Mb/s Ethernet.
644 * Algorithm is that given in RFC 826.
645 * In addition, a sanity check is performed on the sender
646 * protocol address, to catch impersonators.
647 * We no longer handle negotiations for use of trailer protocol:
648 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
649 * along with IP replies if we wanted trailers sent to us,
650 * and also sent them in response to IP replies.
651 * This allowed either end to announce the desire to receive
653 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
654 * but formerly didn't normally send requests.
657 static int log_arp_wrong_iface = 1;
658 static int log_arp_movements = 1;
659 static int log_arp_permanent_modify = 1;
660 static int log_arp_creation_failure = 1;
662 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
663 &log_arp_wrong_iface, 0,
664 "Log arp packets arriving on the wrong interface");
665 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
666 &log_arp_movements, 0,
667 "Log arp replies from MACs different than the one in the cache");
668 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
669 &log_arp_permanent_modify, 0,
670 "Log arp replies from MACs different than the one "
671 "in the permanent arp entry");
672 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_creation_failure, CTLFLAG_RW,
673 &log_arp_creation_failure, 0, "Log arp creation failure");
676 * Returns non-zero if the routine updated anything.
679 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create,
680 boolean_t generate_report, boolean_t dologging)
682 struct arphdr *ah = mtod(m, struct arphdr *);
683 struct ifnet *ifp = m->m_pkthdr.rcvif;
684 struct llinfo_arp *la;
685 struct sockaddr_dl *sdl;
688 char sbuf[INET_ADDRSTRLEN];
689 int changed = create;
691 KASSERT(curthread->td_type == TD_TYPE_NETISR,
692 ("arp update not in netisr"));
694 la = arplookup(saddr, create, generate_report, FALSE);
695 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
696 struct in_addr isaddr = { saddr };
699 * Normally arps coming in on the wrong interface are ignored,
700 * but if we are bridging and the two interfaces belong to
701 * the same bridge, or one is a member of the bridge which
702 * is the other, then it isn't an error.
704 if (rt->rt_ifp != ifp) {
706 * (1) ifp and rt_ifp both members of same bridge
707 * (2) rt_ifp member of bridge ifp
708 * (3) ifp member of bridge rt_ifp
710 * Always replace rt_ifp with the bridge ifc.
714 if (ifp->if_bridge &&
715 rt->rt_ifp->if_bridge == ifp->if_bridge) {
716 nifp = ether_bridge_interface(ifp);
717 } else if (rt->rt_ifp->if_bridge &&
718 ether_bridge_interface(rt->rt_ifp) == ifp) {
720 } else if (ifp->if_bridge &&
721 ether_bridge_interface(ifp) == rt->rt_ifp) {
727 if ((log_arp_wrong_iface == 1 && nifp == NULL) ||
728 log_arp_wrong_iface == 2) {
729 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen,
730 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":");
733 "but got reply from %s on %s\n",
734 kinet_ntoa(isaddr, sbuf),
735 rt->rt_ifp->if_xname, hexstr[0],
742 * nifp is our man! Replace rt_ifp and adjust
745 ifp = rt->rt_ifp = nifp;
746 if (sdl->sdl_type != ifp->if_type) {
747 sdl->sdl_type = ifp->if_type;
750 if (sdl->sdl_index != ifp->if_index) {
751 sdl->sdl_index = ifp->if_index;
756 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) {
758 if (rt->rt_expire != 0) {
759 if (dologging && log_arp_movements) {
760 hexncpy((u_char *)LLADDR(sdl), ifp->if_addrlen,
761 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":");
762 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen,
763 hexstr[1], HEX_NCPYLEN(ifp->if_addrlen), ":");
765 "arp: %s moved from %s to %s on %s\n",
766 kinet_ntoa(isaddr, sbuf), hexstr[0], hexstr[1],
770 if (dologging && log_arp_permanent_modify) {
771 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen,
772 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":");
774 "arp: %s attempts to modify "
775 "permanent entry for %s on %s\n",
776 hexstr[0], kinet_ntoa(isaddr, sbuf), ifp->if_xname);
782 * sanity check for the address length.
783 * XXX this does not work for protocols with variable address
786 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) {
787 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen,
788 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":");
790 "arp from %s: new addr len %d, was %d",
791 hexstr[0], ah->ar_hln, sdl->sdl_alen);
793 if (ifp->if_addrlen != ah->ar_hln) {
795 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen,
796 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":");
798 "arp from %s: addr len: new %d, i/f %d "
799 "(ignored)", hexstr[0],
800 ah->ar_hln, ifp->if_addrlen);
804 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln);
805 if (rt->rt_expire != 0) {
806 if (rt->rt_expire != time_uptime + arpt_keep &&
807 rt->rt_expire != time_uptime + arpt_keep - 1) {
808 rt->rt_expire = time_uptime + arpt_keep;
812 if (rt->rt_flags & RTF_REJECT) {
813 rt->rt_flags &= ~RTF_REJECT;
816 if (la->la_asked != 0) {
820 if (la->la_preempt != arp_maxtries) {
821 la->la_preempt = arp_maxtries;
826 * This particular cpu might have been holding an mbuf
827 * pending ARP resolution. If so, transmit the mbuf now.
829 if (la->la_hold != NULL) {
830 struct mbuf *m = la->la_hold;
833 m_adj(m, sizeof(struct ether_header));
834 ifp->if_output(ifp, m, rt_key(rt), rt);
842 * Called from arpintr() - this routine is run from a single cpu.
845 in_arpinput(struct mbuf *m)
848 struct ifnet *ifp = m->m_pkthdr.rcvif;
849 struct ifaddr_container *ifac;
850 struct in_ifaddr_container *iac;
851 struct in_ifaddr *ia = NULL;
852 struct in_addr isaddr, itaddr, myaddr;
853 uint8_t *enaddr = NULL;
856 char hexstr[64], sbuf[INET_ADDRSTRLEN];
858 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
859 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
860 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
864 ah = mtod(m, struct arphdr *);
865 memcpy(&isaddr, ar_spa(ah), sizeof isaddr);
866 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr);
869 * Check both target and sender IP addresses:
871 * If we receive the packet on the interface owning the address,
872 * then accept the address.
874 * For a bridge, we accept the address if the receive interface and
875 * the interface owning the address are on the same bridge, and
876 * use the bridge MAC as the is-at response. The bridge will be
877 * responsible for handling the packet.
879 * (0) Check target IP against CARP IPs
882 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) {
883 int is_match = 0, is_parent = 0;
887 /* Skip all ia's which don't match */
888 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
891 if (ia->ia_ifp->if_type != IFT_CARP)
894 if (carp_parent(ia->ia_ifp) == ifp)
896 if (is_parent || ia->ia_ifp == ifp)
897 is_match = carp_iamatch(ia);
902 * The parent interface will also receive
903 * the ethernet broadcast packets, e.g. ARP
904 * REQUEST, so if we could find a CARP
905 * interface of the parent that could match
906 * the target IP address, we then drop the
907 * packets, which is delieverd to us through
908 * the parent interface.
919 * (1) Check target IP against our local IPs
921 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) {
924 /* Skip all ia's which don't match */
925 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
929 /* CARP interfaces are checked in (0) */
930 if (ia->ia_ifp->if_type == IFT_CARP)
934 if (ifp->if_bridge && ia->ia_ifp &&
935 ifp->if_bridge == ia->ia_ifp->if_bridge) {
936 ifp = ether_bridge_interface(ifp);
939 if (ia->ia_ifp && ia->ia_ifp->if_bridge &&
940 ether_bridge_interface(ia->ia_ifp) == ifp) {
943 if (ifp->if_bridge && ether_bridge_interface(ifp) ==
947 if (ia->ia_ifp == ifp) {
953 * (2) Check sender IP against our local IPs
955 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) {
958 /* Skip all ia's which don't match */
959 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
962 if (ifp->if_bridge && ia->ia_ifp &&
963 ifp->if_bridge == ia->ia_ifp->if_bridge) {
964 ifp = ether_bridge_interface(ifp);
967 if (ia->ia_ifp && ia->ia_ifp->if_bridge &&
968 ether_bridge_interface(ia->ia_ifp) == ifp) {
971 if (ifp->if_bridge && ether_bridge_interface(ifp) ==
976 if (ia->ia_ifp == ifp)
981 * No match, use the first inet address on the receive interface
982 * as a dummy address for the rest of the function.
984 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) {
985 struct ifaddr *ifa = ifac->ifa;
987 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
994 * If we got here, we didn't find any suitable interface,
995 * so drop the packet.
1002 enaddr = (uint8_t *)IF_LLADDR(ifp);
1003 myaddr = ia->ia_addr.sin_addr;
1004 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) {
1005 m_freem(m); /* it's from me, ignore it. */
1008 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
1010 "arp: link address is broadcast for IP address %s!\n",
1011 kinet_ntoa(isaddr, sbuf));
1015 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
1016 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen,
1017 hexstr, HEX_NCPYLEN(ifp->if_addrlen), ":");
1019 "arp: %s is using my IP address %s!\n",
1020 hexstr, kinet_ntoa(isaddr, sbuf));
1024 if (ifp->if_flags & IFF_STATICARP)
1028 * When arp_restricted_match is true and the ARP response is not
1029 * specifically targetted to me, ignore it. Otherwise the entry
1030 * timeout may be updated for an old MAC.
1032 if (arp_restricted_match && itaddr.s_addr != myaddr.s_addr) {
1038 * Update all CPU's routing tables with this ARP packet.
1040 * However, we only need to generate rtmsg on CPU0.
1042 ASSERT_IN_NETISR(0);
1043 changed = arp_update_oncpu(m, isaddr.s_addr,
1044 itaddr.s_addr == myaddr.s_addr,
1045 RTL_REPORTMSG, TRUE);
1047 if (ncpus > 1 && changed) {
1048 struct netmsg_inarp *msg = &m->m_hdr.mh_arpmsg;
1050 netmsg_init(&msg->base, NULL, &netisr_apanic_rport,
1051 0, arp_update_msghandler);
1053 msg->saddr = isaddr.s_addr;
1054 msg->taddr = itaddr.s_addr;
1055 msg->myaddr = myaddr.s_addr;
1056 lwkt_sendmsg(netisr_cpuport(1), &msg->base.lmsg);
1062 * Just return here; after all CPUs's routing tables are
1063 * properly updated by this ARP packet, an ARP reply will
1064 * be generated if appropriate.
1068 in_arpreply(m, itaddr.s_addr, myaddr.s_addr);
1072 arp_reply_msghandler(netmsg_t msg)
1074 struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg;
1076 in_arpreply(rmsg->m, rmsg->taddr, rmsg->myaddr);
1077 /* Don't reply this netmsg; netmsg_inarp is embedded in mbuf */
1081 arp_update_msghandler(netmsg_t msg)
1083 struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg;
1087 * This message handler will be called on all of the APs;
1088 * no need to generate rtmsg on them.
1090 KASSERT(mycpuid > 0, ("arp update msg on cpu%d", mycpuid));
1091 arp_update_oncpu(rmsg->m, rmsg->saddr,
1092 rmsg->taddr == rmsg->myaddr,
1093 RTL_DONTREPORT, FALSE);
1095 nextcpu = mycpuid + 1;
1096 if (nextcpu < ncpus) {
1097 lwkt_forwardmsg(netisr_cpuport(nextcpu), &rmsg->base.lmsg);
1099 struct mbuf *m = rmsg->m;
1100 in_addr_t saddr = rmsg->saddr;
1101 in_addr_t taddr = rmsg->taddr;
1102 in_addr_t myaddr = rmsg->myaddr;
1105 * Dispatch this mbuf to netisr0 to perform ARP reply,
1107 * NOTE: netmsg_inarp is embedded in this mbuf.
1109 netmsg_init(&rmsg->base, NULL, &netisr_apanic_rport,
1110 0, arp_reply_msghandler);
1112 rmsg->saddr = saddr;
1113 rmsg->taddr = taddr;
1114 rmsg->myaddr = myaddr;
1115 lwkt_sendmsg(netisr_cpuport(0), &rmsg->base.lmsg);
1120 in_arpreply(struct mbuf *m, in_addr_t taddr, in_addr_t myaddr)
1122 struct ifnet *ifp = m->m_pkthdr.rcvif;
1123 const uint8_t *enaddr;
1126 struct ether_header *eh;
1128 ah = mtod(m, struct arphdr *);
1129 if (ntohs(ah->ar_op) != ARPOP_REQUEST) {
1134 enaddr = (const uint8_t *)IF_LLADDR(ifp);
1135 if (taddr == myaddr) {
1136 /* I am the target */
1137 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
1138 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
1140 struct llinfo_arp *la;
1143 la = arplookup(taddr, FALSE, RTL_DONTREPORT, SIN_PROXY);
1145 struct sockaddr_in sin;
1147 char tbuf[INET_ADDRSTRLEN];
1150 if (!arp_proxyall) {
1155 bzero(&sin, sizeof sin);
1156 sin.sin_family = AF_INET;
1157 sin.sin_len = sizeof sin;
1158 sin.sin_addr.s_addr = taddr;
1160 rt = rtpurelookup((struct sockaddr *)&sin);
1167 * Don't send proxies for nodes on the same interface
1168 * as this one came out of, or we'll get into a fight
1169 * over who claims what Ether address.
1171 if (rt->rt_ifp == ifp) {
1175 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
1176 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
1178 kprintf("arp: proxying for %s\n",
1179 kinet_ntoa(itaddr, tbuf));
1182 struct sockaddr_dl *sdl;
1185 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
1186 sdl = SDL(rt->rt_gateway);
1187 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln);
1191 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
1192 memcpy(ar_spa(ah), &taddr, ah->ar_pln);
1193 ah->ar_op = htons(ARPOP_REPLY);
1194 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
1195 switch (ifp->if_type) {
1198 * May not be correct for types not explictly
1199 * listed, but it is our best guess.
1202 eh = (struct ether_header *)sa.sa_data;
1203 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost);
1204 eh->ether_type = htons(ETHERTYPE_ARP);
1207 sa.sa_family = AF_UNSPEC;
1208 sa.sa_len = sizeof sa;
1209 ifp->if_output(ifp, m, &sa, NULL);
1215 * Free an arp entry. If the arp entry is actively referenced or represents
1216 * a static entry we only clear it back to an unresolved state, otherwise
1217 * we destroy the entry entirely.
1219 * Note that static entries are created when route add ... -interface is used
1220 * to create an interface route to a (direct) destination.
1223 arptfree(struct llinfo_arp *la)
1225 struct rtentry *rt = la->la_rt;
1226 struct sockaddr_dl *sdl;
1230 sdl = SDL(rt->rt_gateway);
1232 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) ||
1233 (rt->rt_flags & RTF_STATIC))) {
1235 la->la_preempt = la->la_asked = 0;
1236 rt->rt_flags &= ~RTF_REJECT;
1239 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL);
1243 * Lookup or enter a new address in arptab.
1245 static struct llinfo_arp *
1246 arplookup(in_addr_t addr, boolean_t create, boolean_t generate_report,
1250 struct sockaddr_inarp sin = { sizeof sin, AF_INET };
1251 const char *why = NULL;
1253 /* Check ARP probes, e.g. from Cisco switches. */
1254 if (addr == INADDR_ANY && arp_ignore_probes)
1257 sin.sin_addr.s_addr = addr;
1258 sin.sin_other = proxy ? SIN_PROXY : 0;
1260 rt = _rtlookup((struct sockaddr *)&sin,
1261 generate_report, RTL_DOCLONE);
1263 rt = rtpurelookup((struct sockaddr *)&sin);
1269 if (rt->rt_flags & RTF_GATEWAY)
1270 why = "host is not on local network";
1271 else if (!(rt->rt_flags & RTF_LLINFO))
1272 why = "could not allocate llinfo";
1273 else if (rt->rt_gateway->sa_family != AF_LINK)
1274 why = "gateway route is not ours";
1277 if (create && log_arp_creation_failure) {
1278 char abuf[INET_ADDRSTRLEN];
1280 log(LOG_DEBUG, "arplookup %s failed: %s\n",
1281 kinet_ntoa(sin.sin_addr, abuf), why);
1283 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) {
1284 /* No references to this route. Purge it. */
1285 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
1286 rt_mask(rt), rt->rt_flags, NULL);
1290 return (rt->rt_llinfo);
1294 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
1296 ifa->ifa_rtrequest = arp_rtrequest;
1297 ifa->ifa_flags |= RTF_CLONING;
1301 arp_gratuitous(struct ifnet *ifp, struct ifaddr *ifa)
1303 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) {
1304 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr,
1305 &IA_SIN(ifa)->sin_addr, NULL);
1310 arp_ifaddr(void *arg __unused, struct ifnet *ifp,
1311 enum ifaddr_event event, struct ifaddr *ifa)
1313 if (ifa->ifa_rtrequest != arp_rtrequest) /* XXX need a generic way */
1315 if (ifa->ifa_addr->sa_family != AF_INET)
1317 if (event == IFADDR_EVENT_DELETE)
1321 * - CARP interfaces will take care of gratuitous ARP themselves.
1322 * - If we are the CARP interface's parent, don't send gratuitous
1323 * ARP to avoid unnecessary confusion.
1326 if (ifp->if_type != IFT_CARP && ifp->if_carp == NULL)
1329 arp_gratuitous(ifp, ifa);
1338 for (cpu = 0; cpu < ncpus; cpu++) {
1339 struct arp_pcpu_data *ad = &arp_data[cpu];
1341 LIST_INIT(&ad->llinfo_list);
1342 netmsg_init(&ad->timer_nmsg, NULL, &netisr_adone_rport,
1343 MSGF_PRIORITY, arptimer_dispatch);
1344 callout_init_mp(&ad->timer_ch);
1346 callout_reset_bycpu(&ad->timer_ch, hz, arptimer, NULL, cpu);
1349 netisr_register(NETISR_ARP, arpintr, NULL);
1351 EVENTHANDLER_REGISTER(ifaddr_event, arp_ifaddr, NULL,
1352 EVENTHANDLER_PRI_LAST);
1355 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);