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4 * This code is derived from software contributed to The DragonFly Project
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65 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93
66 * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $
67 * $DragonFly: src/sys/netinet/if_ether.c,v 1.59 2008/11/22 11:03:35 sephe Exp $
71 * Ethernet address resolution protocol.
73 * add "inuse/lock" bit (or ref. count) along with valid bit
79 #include <sys/param.h>
80 #include <sys/kernel.h>
81 #include <sys/queue.h>
82 #include <sys/sysctl.h>
83 #include <sys/systm.h>
85 #include <sys/malloc.h>
86 #include <sys/socket.h>
87 #include <sys/syslog.h>
91 #include <net/if_dl.h>
92 #include <net/if_types.h>
93 #include <net/route.h>
94 #include <net/netisr.h>
95 #include <net/if_llc.h>
97 #include <netinet/in.h>
98 #include <netinet/in_var.h>
99 #include <netinet/if_ether.h>
101 #include <sys/thread2.h>
102 #include <sys/msgport2.h>
103 #include <net/netmsg2.h>
106 #include <netinet/ip_carp.h>
109 #define SIN(s) ((struct sockaddr_in *)s)
110 #define SDL(s) ((struct sockaddr_dl *)s)
112 SYSCTL_DECL(_net_link_ether);
113 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
116 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */
117 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
118 static int arpt_down = 20; /* once declared down, don't send for 20 sec */
120 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
122 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
124 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
127 #define rt_expire rt_rmx.rmx_expire
130 LIST_ENTRY(llinfo_arp) la_le;
131 struct rtentry *la_rt;
132 struct mbuf *la_hold; /* last packet until resolved/timeout */
133 struct lwkt_port *la_msgport; /* last packet's msgport */
134 u_short la_preempt; /* countdown for pre-expiry arps */
135 u_short la_asked; /* #times we QUERIED following expiration */
138 static LIST_HEAD(, llinfo_arp) llinfo_arp_list[MAXCPU];
140 static int arp_maxtries = 5;
141 static int useloopback = 1; /* use loopback interface for local traffic */
142 static int arp_proxyall = 0;
144 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
145 &arp_maxtries, 0, "ARP resolution attempts before returning error");
146 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
147 &useloopback, 0, "Use the loopback interface for local traffic");
148 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
149 &arp_proxyall, 0, "Enable proxy ARP for all suitable requests");
151 static int arp_mpsafe = 1;
152 TUNABLE_INT("net.link.ether.inet.arp_mpsafe", &arp_mpsafe);
154 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *);
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(struct netmsg *);
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 *);
168 static struct callout arptimer_ch[MAXCPU];
171 * Timeout routine. Age arp_tab entries periodically.
175 arptimer(void *ignored_arg)
177 struct llinfo_arp *la, *nla;
180 LIST_FOREACH_MUTABLE(la, &llinfo_arp_list[mycpuid], la_le, nla) {
181 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second)
184 callout_reset(&arptimer_ch[mycpuid], arpt_prune * hz, arptimer, NULL);
189 * Parallel to llc_rtrequest.
192 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info)
194 struct sockaddr *gate = rt->rt_gateway;
195 struct llinfo_arp *la = rt->rt_llinfo;
197 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK };
198 static boolean_t arpinit_done[MAXCPU];
200 if (!arpinit_done[mycpuid]) {
201 arpinit_done[mycpuid] = TRUE;
202 callout_init(&arptimer_ch[mycpuid]);
203 callout_reset(&arptimer_ch[mycpuid], hz, arptimer, NULL);
205 if (rt->rt_flags & RTF_GATEWAY)
211 * XXX: If this is a manually added route to interface
212 * such as older version of routed or gated might provide,
213 * restore cloning bit.
215 if (!(rt->rt_flags & RTF_HOST) &&
216 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
217 rt->rt_flags |= RTF_CLONING;
218 if (rt->rt_flags & RTF_CLONING) {
220 * Case 1: This route should come from a route to iface.
222 rt_setgate(rt, rt_key(rt),
223 (struct sockaddr *)&null_sdl,
225 gate = rt->rt_gateway;
226 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
227 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
228 rt->rt_expire = time_second;
231 /* Announce a new entry if requested. */
232 if (rt->rt_flags & RTF_ANNOUNCE) {
233 arprequest_async(rt->rt_ifp,
234 &SIN(rt_key(rt))->sin_addr,
235 &SIN(rt_key(rt))->sin_addr,
240 if (gate->sa_family != AF_LINK ||
241 gate->sa_len < sizeof(struct sockaddr_dl)) {
242 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
245 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
246 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
248 break; /* This happens on a route change */
250 * Case 2: This route may come from cloning, or a manual route
251 * add with a LL address.
253 R_Malloc(la, struct llinfo_arp *, sizeof *la);
256 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
259 bzero(la, sizeof *la);
261 rt->rt_flags |= RTF_LLINFO;
262 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le);
266 * This keeps the multicast addresses from showing up
267 * in `arp -a' listings as unresolved. It's not actually
268 * functional. Then the same for broadcast.
270 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) {
271 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
273 SDL(gate)->sdl_alen = 6;
276 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) {
277 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr,
278 rt->rt_ifp->if_addrlen);
279 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen;
284 if (SIN(rt_key(rt))->sin_addr.s_addr ==
285 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
287 * This test used to be
288 * if (loif.if_flags & IFF_UP)
289 * It allowed local traffic to be forced
290 * through the hardware by configuring the
291 * loopback down. However, it causes problems
292 * during network configuration for boards
293 * that can't receive packets they send. It
294 * is now necessary to clear "useloopback" and
295 * remove the route to force traffic out to
299 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)),
300 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen);
309 LIST_REMOVE(la, la_le);
310 rt->rt_llinfo = NULL;
311 rt->rt_flags &= ~RTF_LLINFO;
312 if (la->la_hold != NULL)
313 m_freem(la->la_hold);
320 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip,
321 const struct in_addr *tip, const u_char *enaddr)
327 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL)
329 m->m_pkthdr.rcvif = NULL;
331 switch (ifp->if_type) {
334 * This may not be correct for types not explicitly
335 * listed, but this is our best guess
338 ar_hrd = htons(ARPHRD_ETHER);
340 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
341 m->m_pkthdr.len = m->m_len;
342 MH_ALIGN(m, m->m_len);
344 ah = mtod(m, struct arphdr *);
349 ah->ar_pro = htons(ETHERTYPE_IP);
350 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
351 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
352 ah->ar_op = htons(ARPOP_REQUEST);
353 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
354 memset(ar_tha(ah), 0, ah->ar_hln);
355 memcpy(ar_spa(ah), sip, ah->ar_pln);
356 memcpy(ar_tpa(ah), tip, ah->ar_pln);
362 arpreq_send(struct ifnet *ifp, struct mbuf *m)
365 struct ether_header *eh;
367 switch (ifp->if_type) {
370 * This may not be correct for types not explicitly
371 * listed, but this is our best guess
374 eh = (struct ether_header *)sa.sa_data;
375 /* if_output() will not swap */
376 eh->ether_type = htons(ETHERTYPE_ARP);
377 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen);
381 sa.sa_family = AF_UNSPEC;
382 sa.sa_len = sizeof(sa);
383 ifp->if_output(ifp, m, &sa, NULL);
387 arpreq_send_handler(struct netmsg *nmsg)
389 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet;
390 struct ifnet *ifp = nmsg->nm_lmsg.u.ms_resultp;
393 /* nmsg was embedded in the mbuf, do not reply! */
397 * Broadcast an ARP request. Caller specifies:
398 * - arp header source ip address
399 * - arp header target ip address
400 * - arp header source ethernet address
402 * NOTE: Caller MUST NOT hold ifp's serializer
405 arprequest(struct ifnet *ifp, const struct in_addr *sip,
406 const struct in_addr *tip, const u_char *enaddr)
410 m = arpreq_alloc(ifp, sip, tip, enaddr);
417 * Same as arprequest(), except:
418 * - Caller is allowed to hold ifp's serializer
419 * - Network output is done in TDF_NETWORK kernel thread
422 arprequest_async(struct ifnet *ifp, const struct in_addr *sip,
423 const struct in_addr *tip, const u_char *enaddr)
426 struct netmsg_packet *pmsg;
428 m = arpreq_alloc(ifp, sip, tip, enaddr);
432 pmsg = &m->m_hdr.mh_netmsg;
433 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 0,
434 arpreq_send_handler);
436 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = ifp;
438 lwkt_sendmsg(cpu_portfn(mycpuid), &pmsg->nm_netmsg.nm_lmsg);
442 * Resolve an IP address into an ethernet address. If success,
443 * desten is filled in. If there is no entry in arptab,
444 * set one up and broadcast a request for the IP address.
445 * Hold onto this mbuf and resend it once the address
446 * is finally resolved. A return value of 1 indicates
447 * that desten has been filled in and the packet should be sent
448 * normally; a 0 return indicates that the packet has been
449 * taken over here, either now or for later transmission.
452 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
453 struct sockaddr *dst, u_char *desten)
456 struct llinfo_arp *la = NULL;
457 struct sockaddr_dl *sdl;
459 if (m->m_flags & M_BCAST) { /* broadcast */
460 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen);
463 if (m->m_flags & M_MCAST) {/* multicast */
464 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
468 if (rt_llroute(dst, rt0, &rt) != 0) {
475 la = arplookup(SIN(dst)->sin_addr.s_addr,
476 TRUE, RTL_REPORTMSG, FALSE);
480 if (la == NULL || rt == NULL) {
481 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n",
482 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ",
487 sdl = SDL(rt->rt_gateway);
489 * Check the address family and length is valid, the address
490 * is resolved; otherwise, try to resolve.
492 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) &&
493 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
495 * If entry has an expiry time and it is approaching,
496 * see if we need to send an ARP request within this
497 * arpt_down interval.
499 if ((rt->rt_expire != 0) &&
500 (time_second + la->la_preempt > rt->rt_expire)) {
502 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
508 bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
512 * If ARP is disabled or static on this interface, stop.
514 * Probably should not allocate empty llinfo struct if we are
515 * not going to be sending out an arp request.
517 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) {
522 * There is an arptab entry, but no ethernet address
523 * response yet. Replace the held mbuf with this
526 if (la->la_hold != NULL)
527 m_freem(la->la_hold);
529 la->la_msgport = curnetport;
530 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) {
531 rt->rt_flags &= ~RTF_REJECT;
532 if (la->la_asked == 0 || rt->rt_expire != time_second) {
533 rt->rt_expire = time_second;
534 if (la->la_asked++ < arp_maxtries) {
536 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
540 rt->rt_flags |= RTF_REJECT;
541 rt->rt_expire += arpt_down;
543 la->la_preempt = arp_maxtries;
551 * Common length and type checks are done here,
552 * then the protocol-specific routine is called.
555 arpintr(struct netmsg *msg)
557 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet;
561 if (m->m_len < sizeof(struct arphdr) &&
562 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) {
563 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
566 ar = mtod(m, struct arphdr *);
568 ar_hrd = ntohs(ar->ar_hrd);
569 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) {
570 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
571 (unsigned char *)&ar->ar_hrd, "");
576 if (m->m_pkthdr.len < arphdr_len(ar)) {
577 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
578 log(LOG_ERR, "arp: runt packet\n");
581 ar = mtod(m, struct arphdr *);
584 switch (ntohs(ar->ar_pro)) {
592 /* msg was embedded in the mbuf, do not reply! */
597 * ARP for Internet protocols on 10 Mb/s Ethernet.
598 * Algorithm is that given in RFC 826.
599 * In addition, a sanity check is performed on the sender
600 * protocol address, to catch impersonators.
601 * We no longer handle negotiations for use of trailer protocol:
602 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
603 * along with IP replies if we wanted trailers sent to us,
604 * and also sent them in response to IP replies.
605 * This allowed either end to announce the desire to receive
607 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
608 * but formerly didn't normally send requests.
611 static int log_arp_wrong_iface = 1;
612 static int log_arp_movements = 1;
613 static int log_arp_permanent_modify = 1;
615 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
616 &log_arp_wrong_iface, 0,
617 "Log arp packets arriving on the wrong interface");
618 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
619 &log_arp_movements, 0,
620 "Log arp replies from MACs different than the one in the cache");
621 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
622 &log_arp_permanent_modify, 0,
623 "Log arp replies from MACs different than the one "
624 "in the permanent arp entry");
628 arp_hold_output(struct netmsg *nmsg)
630 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet;
634 rt = nmsg->nm_lmsg.u.ms_resultp;
635 ifp = m->m_pkthdr.rcvif;
636 m->m_pkthdr.rcvif = NULL;
638 ifp->if_output(ifp, m, rt_key(rt), rt);
640 /* Drop the reference count bumped by the sender */
643 /* nmsg was embedded in the mbuf, do not reply! */
647 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create,
648 boolean_t generate_report, boolean_t dologging)
650 struct arphdr *ah = mtod(m, struct arphdr *);
651 struct ifnet *ifp = m->m_pkthdr.rcvif;
652 struct llinfo_arp *la;
653 struct sockaddr_dl *sdl;
656 la = arplookup(saddr, create, generate_report, FALSE);
657 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
658 struct in_addr isaddr = { saddr };
660 /* the following is not an error when doing bridging */
661 if (rt->rt_ifp != ifp) {
662 if (dologging && log_arp_wrong_iface) {
665 "but got reply from %*D on %s\n",
667 rt->rt_ifp->if_xname,
668 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
674 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) {
675 if (rt->rt_expire != 0) {
676 if (dologging && log_arp_movements) {
678 "arp: %s moved from %*D to %*D on %s\n",
680 ifp->if_addrlen, (u_char *)LLADDR(sdl),
681 ":", ifp->if_addrlen,
682 (u_char *)ar_sha(ah), ":",
686 if (dologging && log_arp_permanent_modify) {
688 "arp: %*D attempts to modify "
689 "permanent entry for %s on %s\n",
690 ifp->if_addrlen, (u_char *)ar_sha(ah),
691 ":", inet_ntoa(isaddr), ifp->if_xname);
697 * sanity check for the address length.
698 * XXX this does not work for protocols with variable address
701 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) {
703 "arp from %*D: new addr len %d, was %d",
704 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
705 ah->ar_hln, sdl->sdl_alen);
707 if (ifp->if_addrlen != ah->ar_hln) {
710 "arp from %*D: addr len: new %d, i/f %d "
712 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
713 ah->ar_hln, ifp->if_addrlen);
717 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln);
718 if (rt->rt_expire != 0)
719 rt->rt_expire = time_second + arpt_keep;
720 rt->rt_flags &= ~RTF_REJECT;
722 la->la_preempt = arp_maxtries;
725 * This particular cpu might have been holding an mbuf
726 * pending ARP resolution. If so, transmit the mbuf now.
728 if (la->la_hold != NULL) {
729 struct mbuf *m = la->la_hold;
730 struct lwkt_port *port = la->la_msgport;
731 struct netmsg_packet *pmsg;
734 la->la_msgport = NULL;
736 m_adj(m, sizeof(struct ether_header));
739 * Make sure that this rtentry will not be freed
740 * before the packet is processed on the target
741 * msgport. The reference count will be dropped
742 * in the handler associated with this packet.
746 pmsg = &m->m_hdr.mh_netmsg;
747 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport,
748 MSGF_MPSAFE | MSGF_PRIORITY,
752 /* Record necessary information */
753 m->m_pkthdr.rcvif = ifp;
754 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = rt;
756 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg);
763 struct netmsg_arp_update {
764 struct netmsg netmsg;
770 static void arp_update_msghandler(struct netmsg *);
775 * Called from arpintr() - this routine is run from a single cpu.
778 in_arpinput(struct mbuf *m)
781 struct ifnet *ifp = m->m_pkthdr.rcvif;
782 struct ether_header *eh;
784 struct ifaddr_container *ifac;
785 struct in_ifaddr_container *iac;
786 struct in_ifaddr *ia = NULL;
788 struct in_addr isaddr, itaddr, myaddr;
790 struct netmsg_arp_update msg;
792 uint8_t *enaddr = NULL;
796 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
797 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
798 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
802 ah = mtod(m, struct arphdr *);
803 op = ntohs(ah->ar_op);
804 memcpy(&isaddr, ar_spa(ah), sizeof isaddr);
805 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr);
807 myaddr.s_addr = INADDR_ANY;
809 if (ifp->if_carp != NULL) {
811 if (ifp->if_carp != NULL &&
812 carp_iamatch(ifp->if_carp, &itaddr, &isaddr, &enaddr)) {
822 * Check both target and sender IP addresses:
824 * If we receive the packet on the interface owning the address,
825 * then accept the address.
827 * For a bridge, we accept the address if the receive interface and
828 * the interface owning the address are on the same bridge.
829 * (This will change slightly when we have clusters of interfaces).
831 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) {
834 /* Skip all ia's which don't match */
835 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
838 if (ia->ia_ifp->if_type == IFT_CARP)
841 if (ia->ia_ifp == ifp)
844 if (ifp->if_bridge && ia->ia_ifp &&
845 ifp->if_bridge == ia->ia_ifp->if_bridge)
848 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) {
851 /* Skip all ia's which don't match */
852 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
855 if (ia->ia_ifp->if_type == IFT_CARP)
858 if (ia->ia_ifp == ifp)
861 if (ifp->if_bridge && ia->ia_ifp &&
862 ifp->if_bridge == ia->ia_ifp->if_bridge)
866 * No match, use the first inet address on the receive interface
867 * as a dummy address for the rest of the function.
869 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) {
870 struct ifaddr *ifa = ifac->ifa;
872 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
878 * If we got here, we didn't find any suitable interface,
879 * so drop the packet.
886 enaddr = (uint8_t *)IF_LLADDR(ifp);
887 if (myaddr.s_addr == INADDR_ANY)
888 myaddr = ia->ia_addr.sin_addr;
889 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) {
890 m_freem(m); /* it's from me, ignore it. */
893 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
895 "arp: link address is broadcast for IP address %s!\n",
900 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
902 "arp: %*D is using my IP address %s!\n",
903 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
908 if (ifp->if_flags & IFF_STATICARP)
911 netmsg_init(&msg.netmsg, &curthread->td_msgport, 0,
912 arp_update_msghandler);
914 msg.saddr = isaddr.s_addr;
915 msg.create = (itaddr.s_addr == myaddr.s_addr);
916 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0);
918 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr),
919 RTL_REPORTMSG, TRUE);
922 if (op != ARPOP_REQUEST) {
926 if (itaddr.s_addr == myaddr.s_addr) {
927 /* I am the target */
928 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
929 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
931 struct llinfo_arp *la;
933 la = arplookup(itaddr.s_addr, FALSE, RTL_DONTREPORT, SIN_PROXY);
935 struct sockaddr_in sin;
942 bzero(&sin, sizeof sin);
943 sin.sin_family = AF_INET;
944 sin.sin_len = sizeof sin;
945 sin.sin_addr = itaddr;
947 rt = rtpurelookup((struct sockaddr *)&sin);
954 * Don't send proxies for nodes on the same interface
955 * as this one came out of, or we'll get into a fight
956 * over who claims what Ether address.
958 if (rt->rt_ifp == ifp) {
962 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
963 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
965 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr));
968 struct sockaddr_dl *sdl;
971 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
972 sdl = SDL(rt->rt_gateway);
973 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln);
977 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
978 memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
979 ah->ar_op = htons(ARPOP_REPLY);
980 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
981 switch (ifp->if_type) {
984 * May not be correct for types not explictly
985 * listed, but it is our best guess.
988 eh = (struct ether_header *)sa.sa_data;
989 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost);
990 eh->ether_type = htons(ETHERTYPE_ARP);
993 sa.sa_family = AF_UNSPEC;
994 sa.sa_len = sizeof sa;
995 ifp->if_output(ifp, m, &sa, NULL);
1001 arp_update_msghandler(struct netmsg *netmsg)
1003 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg;
1007 * This message handler will be called on all of the CPUs,
1008 * however, we only need to generate rtmsg on CPU0.
1010 arp_update_oncpu(msg->m, msg->saddr, msg->create,
1011 mycpuid == 0 ? RTL_REPORTMSG : RTL_DONTREPORT,
1014 nextcpu = mycpuid + 1;
1015 if (nextcpu < ncpus)
1016 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg);
1018 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0);
1026 * Free an arp entry. If the arp entry is actively referenced or represents
1027 * a static entry we only clear it back to an unresolved state, otherwise
1028 * we destroy the entry entirely.
1030 * Note that static entries are created when route add ... -interface is used
1031 * to create an interface route to a (direct) destination.
1034 arptfree(struct llinfo_arp *la)
1036 struct rtentry *rt = la->la_rt;
1037 struct sockaddr_dl *sdl;
1041 sdl = SDL(rt->rt_gateway);
1043 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) ||
1044 (rt->rt_flags & RTF_STATIC))) {
1046 la->la_preempt = la->la_asked = 0;
1047 rt->rt_flags &= ~RTF_REJECT;
1050 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL);
1054 * Lookup or enter a new address in arptab.
1056 static struct llinfo_arp *
1057 arplookup(in_addr_t addr, boolean_t create, boolean_t generate_report,
1061 struct sockaddr_inarp sin = { sizeof sin, AF_INET };
1062 const char *why = NULL;
1064 sin.sin_addr.s_addr = addr;
1065 sin.sin_other = proxy ? SIN_PROXY : 0;
1067 rt = _rtlookup((struct sockaddr *)&sin,
1068 generate_report, RTL_DOCLONE);
1070 rt = rtpurelookup((struct sockaddr *)&sin);
1076 if (rt->rt_flags & RTF_GATEWAY)
1077 why = "host is not on local network";
1078 else if (!(rt->rt_flags & RTF_LLINFO))
1079 why = "could not allocate llinfo";
1080 else if (rt->rt_gateway->sa_family != AF_LINK)
1081 why = "gateway route is not ours";
1085 log(LOG_DEBUG, "arplookup %s failed: %s\n",
1086 inet_ntoa(sin.sin_addr), why);
1088 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) {
1089 /* No references to this route. Purge it. */
1090 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
1091 rt_mask(rt), rt->rt_flags, NULL);
1095 return (rt->rt_llinfo);
1099 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
1101 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) {
1102 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr,
1103 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
1105 ifa->ifa_rtrequest = arp_rtrequest;
1106 ifa->ifa_flags |= RTF_CLONING;
1110 arp_iainit(struct ifnet *ifp, const struct in_addr *addr, const u_char *enaddr)
1112 if (addr->s_addr != INADDR_ANY)
1113 arprequest_async(ifp, addr, addr, enaddr);
1122 for (cpu = 0; cpu < ncpus2; cpu++)
1123 LIST_INIT(&llinfo_arp_list[cpu]);
1126 flags = NETISR_FLAG_MPSAFE;
1127 kprintf("arp: MPSAFE\n");
1129 flags = NETISR_FLAG_NOTMPSAFE;
1131 netisr_register(NETISR_ARP, cpu0_portfn, pktinfo_portfn_cpu0,
1135 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);