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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>
104 #include <sys/mplock2.h>
107 #include <netinet/ip_carp.h>
110 #define SIN(s) ((struct sockaddr_in *)s)
111 #define SDL(s) ((struct sockaddr_dl *)s)
113 SYSCTL_DECL(_net_link_ether);
114 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
117 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */
118 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
119 static int arpt_down = 20; /* once declared down, don't send for 20 sec */
121 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
123 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
125 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
128 #define rt_expire rt_rmx.rmx_expire
131 LIST_ENTRY(llinfo_arp) la_le;
132 struct rtentry *la_rt;
133 struct mbuf *la_hold; /* last packet until resolved/timeout */
134 struct lwkt_port *la_msgport; /* last packet's msgport */
135 u_short la_preempt; /* countdown for pre-expiry arps */
136 u_short la_asked; /* #times we QUERIED following expiration */
139 static LIST_HEAD(, llinfo_arp) llinfo_arp_list[MAXCPU];
141 static int arp_maxtries = 5;
142 static int useloopback = 1; /* use loopback interface for local traffic */
143 static int arp_proxyall = 0;
145 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
146 &arp_maxtries, 0, "ARP resolution attempts before returning error");
147 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
148 &useloopback, 0, "Use the loopback interface for local traffic");
149 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
150 &arp_proxyall, 0, "Enable proxy ARP for all suitable requests");
152 static int arp_mpsafe = 1;
153 TUNABLE_INT("net.link.ether.inet.arp_mpsafe", &arp_mpsafe);
155 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *);
156 static void arprequest(struct ifnet *, const struct in_addr *,
157 const struct in_addr *, const u_char *);
158 static void arprequest_async(struct ifnet *, const struct in_addr *,
159 const struct in_addr *, const u_char *);
160 static void arpintr(struct netmsg *);
161 static void arptfree(struct llinfo_arp *);
162 static void arptimer(void *);
163 static struct llinfo_arp *
164 arplookup(in_addr_t, boolean_t, boolean_t, boolean_t);
166 static void in_arpinput(struct mbuf *);
169 static struct callout arptimer_ch[MAXCPU];
172 * Timeout routine. Age arp_tab entries periodically.
176 arptimer(void *ignored_arg)
178 struct llinfo_arp *la, *nla;
181 LIST_FOREACH_MUTABLE(la, &llinfo_arp_list[mycpuid], la_le, nla) {
182 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second)
185 callout_reset(&arptimer_ch[mycpuid], arpt_prune * hz, arptimer, NULL);
190 * Parallel to llc_rtrequest.
193 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info)
195 struct sockaddr *gate = rt->rt_gateway;
196 struct llinfo_arp *la = rt->rt_llinfo;
198 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK };
199 static boolean_t arpinit_done[MAXCPU];
201 if (!arpinit_done[mycpuid]) {
202 arpinit_done[mycpuid] = TRUE;
203 callout_init(&arptimer_ch[mycpuid]);
204 callout_reset(&arptimer_ch[mycpuid], hz, arptimer, NULL);
206 if (rt->rt_flags & RTF_GATEWAY)
212 * XXX: If this is a manually added route to interface
213 * such as older version of routed or gated might provide,
214 * restore cloning bit.
216 if (!(rt->rt_flags & RTF_HOST) &&
217 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
218 rt->rt_flags |= RTF_CLONING;
219 if (rt->rt_flags & RTF_CLONING) {
221 * Case 1: This route should come from a route to iface.
223 rt_setgate(rt, rt_key(rt),
224 (struct sockaddr *)&null_sdl,
226 gate = rt->rt_gateway;
227 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
228 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
229 rt->rt_expire = time_second;
232 /* Announce a new entry if requested. */
233 if (rt->rt_flags & RTF_ANNOUNCE) {
234 arprequest_async(rt->rt_ifp,
235 &SIN(rt_key(rt))->sin_addr,
236 &SIN(rt_key(rt))->sin_addr,
241 if (gate->sa_family != AF_LINK ||
242 gate->sa_len < sizeof(struct sockaddr_dl)) {
243 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
246 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
247 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
249 break; /* This happens on a route change */
251 * Case 2: This route may come from cloning, or a manual route
252 * add with a LL address.
254 R_Malloc(la, struct llinfo_arp *, sizeof *la);
257 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
260 bzero(la, sizeof *la);
262 rt->rt_flags |= RTF_LLINFO;
263 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le);
267 * This keeps the multicast addresses from showing up
268 * in `arp -a' listings as unresolved. It's not actually
269 * functional. Then the same for broadcast.
271 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) {
272 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
274 SDL(gate)->sdl_alen = 6;
277 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) {
278 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr,
279 rt->rt_ifp->if_addrlen);
280 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen;
285 if (SIN(rt_key(rt))->sin_addr.s_addr ==
286 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
288 * This test used to be
289 * if (loif.if_flags & IFF_UP)
290 * It allowed local traffic to be forced
291 * through the hardware by configuring the
292 * loopback down. However, it causes problems
293 * during network configuration for boards
294 * that can't receive packets they send. It
295 * is now necessary to clear "useloopback" and
296 * remove the route to force traffic out to
300 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)),
301 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen);
310 LIST_REMOVE(la, la_le);
311 rt->rt_llinfo = NULL;
312 rt->rt_flags &= ~RTF_LLINFO;
313 if (la->la_hold != NULL)
314 m_freem(la->la_hold);
321 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip,
322 const struct in_addr *tip, const u_char *enaddr)
328 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL)
330 m->m_pkthdr.rcvif = NULL;
332 switch (ifp->if_type) {
335 * This may not be correct for types not explicitly
336 * listed, but this is our best guess
339 ar_hrd = htons(ARPHRD_ETHER);
341 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
342 m->m_pkthdr.len = m->m_len;
343 MH_ALIGN(m, m->m_len);
345 ah = mtod(m, struct arphdr *);
350 ah->ar_pro = htons(ETHERTYPE_IP);
351 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
352 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
353 ah->ar_op = htons(ARPOP_REQUEST);
354 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
355 memset(ar_tha(ah), 0, ah->ar_hln);
356 memcpy(ar_spa(ah), sip, ah->ar_pln);
357 memcpy(ar_tpa(ah), tip, ah->ar_pln);
363 arpreq_send(struct ifnet *ifp, struct mbuf *m)
366 struct ether_header *eh;
368 switch (ifp->if_type) {
371 * This may not be correct for types not explicitly
372 * listed, but this is our best guess
375 eh = (struct ether_header *)sa.sa_data;
376 /* if_output() will not swap */
377 eh->ether_type = htons(ETHERTYPE_ARP);
378 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen);
382 sa.sa_family = AF_UNSPEC;
383 sa.sa_len = sizeof(sa);
384 ifp->if_output(ifp, m, &sa, NULL);
388 arpreq_send_handler(struct netmsg *nmsg)
390 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet;
391 struct ifnet *ifp = nmsg->nm_lmsg.u.ms_resultp;
394 /* nmsg was embedded in the mbuf, do not reply! */
398 * Broadcast an ARP request. Caller specifies:
399 * - arp header source ip address
400 * - arp header target ip address
401 * - arp header source ethernet address
403 * NOTE: Caller MUST NOT hold ifp's serializer
406 arprequest(struct ifnet *ifp, const struct in_addr *sip,
407 const struct in_addr *tip, const u_char *enaddr)
411 m = arpreq_alloc(ifp, sip, tip, enaddr);
418 * Same as arprequest(), except:
419 * - Caller is allowed to hold ifp's serializer
420 * - Network output is done in TDF_NETWORK kernel thread
423 arprequest_async(struct ifnet *ifp, const struct in_addr *sip,
424 const struct in_addr *tip, const u_char *enaddr)
427 struct netmsg_packet *pmsg;
429 m = arpreq_alloc(ifp, sip, tip, enaddr);
433 pmsg = &m->m_hdr.mh_netmsg;
434 netmsg_init(&pmsg->nm_netmsg, NULL, &netisr_apanic_rport,
435 0, arpreq_send_handler);
437 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = ifp;
439 lwkt_sendmsg(cpu_portfn(mycpuid), &pmsg->nm_netmsg.nm_lmsg);
443 * Resolve an IP address into an ethernet address. If success,
444 * desten is filled in. If there is no entry in arptab,
445 * set one up and broadcast a request for the IP address.
446 * Hold onto this mbuf and resend it once the address
447 * is finally resolved. A return value of 1 indicates
448 * that desten has been filled in and the packet should be sent
449 * normally; a 0 return indicates that the packet has been
450 * taken over here, either now or for later transmission.
453 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
454 struct sockaddr *dst, u_char *desten)
457 struct llinfo_arp *la = NULL;
458 struct sockaddr_dl *sdl;
460 if (m->m_flags & M_BCAST) { /* broadcast */
461 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen);
464 if (m->m_flags & M_MCAST) {/* multicast */
465 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
469 if (rt_llroute(dst, rt0, &rt) != 0) {
476 la = arplookup(SIN(dst)->sin_addr.s_addr,
477 TRUE, RTL_REPORTMSG, FALSE);
481 if (la == NULL || rt == NULL) {
482 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n",
483 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ",
488 sdl = SDL(rt->rt_gateway);
490 * Check the address family and length is valid, the address
491 * is resolved; otherwise, try to resolve.
493 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) &&
494 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
496 * If entry has an expiry time and it is approaching,
497 * see if we need to send an ARP request within this
498 * arpt_down interval.
500 if ((rt->rt_expire != 0) &&
501 (time_second + la->la_preempt > rt->rt_expire)) {
503 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
509 bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
513 * If ARP is disabled or static on this interface, stop.
515 * Probably should not allocate empty llinfo struct if we are
516 * not going to be sending out an arp request.
518 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) {
523 * There is an arptab entry, but no ethernet address
524 * response yet. Replace the held mbuf with this
527 if (la->la_hold != NULL)
528 m_freem(la->la_hold);
530 la->la_msgport = curnetport;
531 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) {
532 rt->rt_flags &= ~RTF_REJECT;
533 if (la->la_asked == 0 || rt->rt_expire != time_second) {
534 rt->rt_expire = time_second;
535 if (la->la_asked++ < arp_maxtries) {
537 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
541 rt->rt_flags |= RTF_REJECT;
542 rt->rt_expire += arpt_down;
544 la->la_preempt = arp_maxtries;
552 * Common length and type checks are done here,
553 * then the protocol-specific routine is called.
556 arpintr(struct netmsg *msg)
558 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet;
562 if (m->m_len < sizeof(struct arphdr) &&
563 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) {
564 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
567 ar = mtod(m, struct arphdr *);
569 ar_hrd = ntohs(ar->ar_hrd);
570 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) {
571 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
572 (unsigned char *)&ar->ar_hrd, "");
577 if (m->m_pkthdr.len < arphdr_len(ar)) {
578 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
579 log(LOG_ERR, "arp: runt packet\n");
582 ar = mtod(m, struct arphdr *);
585 switch (ntohs(ar->ar_pro)) {
593 /* msg was embedded in the mbuf, do not reply! */
598 * ARP for Internet protocols on 10 Mb/s Ethernet.
599 * Algorithm is that given in RFC 826.
600 * In addition, a sanity check is performed on the sender
601 * protocol address, to catch impersonators.
602 * We no longer handle negotiations for use of trailer protocol:
603 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
604 * along with IP replies if we wanted trailers sent to us,
605 * and also sent them in response to IP replies.
606 * This allowed either end to announce the desire to receive
608 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
609 * but formerly didn't normally send requests.
612 static int log_arp_wrong_iface = 1;
613 static int log_arp_movements = 1;
614 static int log_arp_permanent_modify = 1;
616 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
617 &log_arp_wrong_iface, 0,
618 "Log arp packets arriving on the wrong interface");
619 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
620 &log_arp_movements, 0,
621 "Log arp replies from MACs different than the one in the cache");
622 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
623 &log_arp_permanent_modify, 0,
624 "Log arp replies from MACs different than the one "
625 "in the permanent arp entry");
629 arp_hold_output(struct netmsg *nmsg)
631 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet;
635 rt = nmsg->nm_lmsg.u.ms_resultp;
636 ifp = m->m_pkthdr.rcvif;
637 m->m_pkthdr.rcvif = NULL;
639 ifp->if_output(ifp, m, rt_key(rt), rt);
641 /* Drop the reference count bumped by the sender */
644 /* nmsg was embedded in the mbuf, do not reply! */
648 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create,
649 boolean_t generate_report, boolean_t dologging)
651 struct arphdr *ah = mtod(m, struct arphdr *);
652 struct ifnet *ifp = m->m_pkthdr.rcvif;
653 struct llinfo_arp *la;
654 struct sockaddr_dl *sdl;
657 la = arplookup(saddr, create, generate_report, FALSE);
658 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
659 struct in_addr isaddr = { saddr };
661 /* the following is not an error when doing bridging */
662 if (rt->rt_ifp != ifp) {
663 if (dologging && log_arp_wrong_iface) {
666 "but got reply from %*D on %s\n",
668 rt->rt_ifp->if_xname,
669 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
675 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) {
676 if (rt->rt_expire != 0) {
677 if (dologging && log_arp_movements) {
679 "arp: %s moved from %*D to %*D on %s\n",
681 ifp->if_addrlen, (u_char *)LLADDR(sdl),
682 ":", ifp->if_addrlen,
683 (u_char *)ar_sha(ah), ":",
687 if (dologging && log_arp_permanent_modify) {
689 "arp: %*D attempts to modify "
690 "permanent entry for %s on %s\n",
691 ifp->if_addrlen, (u_char *)ar_sha(ah),
692 ":", inet_ntoa(isaddr), ifp->if_xname);
698 * sanity check for the address length.
699 * XXX this does not work for protocols with variable address
702 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) {
704 "arp from %*D: new addr len %d, was %d",
705 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
706 ah->ar_hln, sdl->sdl_alen);
708 if (ifp->if_addrlen != ah->ar_hln) {
711 "arp from %*D: addr len: new %d, i/f %d "
713 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
714 ah->ar_hln, ifp->if_addrlen);
718 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln);
719 if (rt->rt_expire != 0)
720 rt->rt_expire = time_second + arpt_keep;
721 rt->rt_flags &= ~RTF_REJECT;
723 la->la_preempt = arp_maxtries;
726 * This particular cpu might have been holding an mbuf
727 * pending ARP resolution. If so, transmit the mbuf now.
729 if (la->la_hold != NULL) {
730 struct mbuf *m = la->la_hold;
731 struct lwkt_port *port = la->la_msgport;
732 struct netmsg_packet *pmsg;
735 la->la_msgport = NULL;
737 m_adj(m, sizeof(struct ether_header));
740 * Make sure that this rtentry will not be freed
741 * before the packet is processed on the target
742 * msgport. The reference count will be dropped
743 * in the handler associated with this packet.
747 pmsg = &m->m_hdr.mh_netmsg;
748 netmsg_init(&pmsg->nm_netmsg, NULL,
749 &netisr_apanic_rport,
750 MSGF_MPSAFE | MSGF_PRIORITY,
754 /* Record necessary information */
755 m->m_pkthdr.rcvif = ifp;
756 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = rt;
758 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg);
765 struct netmsg_arp_update {
766 struct netmsg netmsg;
772 static void arp_update_msghandler(struct netmsg *);
777 * Called from arpintr() - this routine is run from a single cpu.
780 in_arpinput(struct mbuf *m)
783 struct ifnet *ifp = m->m_pkthdr.rcvif;
784 struct ether_header *eh;
786 struct ifaddr_container *ifac;
787 struct in_ifaddr_container *iac;
788 struct in_ifaddr *ia = NULL;
790 struct in_addr isaddr, itaddr, myaddr;
792 struct netmsg_arp_update msg;
794 uint8_t *enaddr = NULL;
798 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
799 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
800 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
804 ah = mtod(m, struct arphdr *);
805 op = ntohs(ah->ar_op);
806 memcpy(&isaddr, ar_spa(ah), sizeof isaddr);
807 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr);
809 myaddr.s_addr = INADDR_ANY;
811 if (ifp->if_carp != NULL) {
813 if (ifp->if_carp != NULL &&
814 carp_iamatch(ifp->if_carp, &itaddr, &isaddr, &enaddr)) {
824 * Check both target and sender IP addresses:
826 * If we receive the packet on the interface owning the address,
827 * then accept the address.
829 * For a bridge, we accept the address if the receive interface and
830 * the interface owning the address are on the same bridge.
831 * (This will change slightly when we have clusters of interfaces).
833 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) {
836 /* Skip all ia's which don't match */
837 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
840 if (ia->ia_ifp->if_type == IFT_CARP)
843 if (ia->ia_ifp == ifp)
846 if (ifp->if_bridge && ia->ia_ifp &&
847 ifp->if_bridge == ia->ia_ifp->if_bridge)
850 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) {
853 /* Skip all ia's which don't match */
854 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
857 if (ia->ia_ifp->if_type == IFT_CARP)
860 if (ia->ia_ifp == ifp)
863 if (ifp->if_bridge && ia->ia_ifp &&
864 ifp->if_bridge == ia->ia_ifp->if_bridge)
868 * No match, use the first inet address on the receive interface
869 * as a dummy address for the rest of the function.
871 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) {
872 struct ifaddr *ifa = ifac->ifa;
874 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
880 * If we got here, we didn't find any suitable interface,
881 * so drop the packet.
888 enaddr = (uint8_t *)IF_LLADDR(ifp);
889 if (myaddr.s_addr == INADDR_ANY)
890 myaddr = ia->ia_addr.sin_addr;
891 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) {
892 m_freem(m); /* it's from me, ignore it. */
895 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
897 "arp: link address is broadcast for IP address %s!\n",
902 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
904 "arp: %*D is using my IP address %s!\n",
905 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
910 if (ifp->if_flags & IFF_STATICARP)
913 netmsg_init(&msg.netmsg, NULL, &curthread->td_msgport,
914 0, arp_update_msghandler);
916 msg.saddr = isaddr.s_addr;
917 msg.create = (itaddr.s_addr == myaddr.s_addr);
918 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0);
920 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr),
921 RTL_REPORTMSG, TRUE);
924 if (op != ARPOP_REQUEST) {
928 if (itaddr.s_addr == myaddr.s_addr) {
929 /* I am the target */
930 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
931 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
933 struct llinfo_arp *la;
935 la = arplookup(itaddr.s_addr, FALSE, RTL_DONTREPORT, SIN_PROXY);
937 struct sockaddr_in sin;
944 bzero(&sin, sizeof sin);
945 sin.sin_family = AF_INET;
946 sin.sin_len = sizeof sin;
947 sin.sin_addr = itaddr;
949 rt = rtpurelookup((struct sockaddr *)&sin);
956 * Don't send proxies for nodes on the same interface
957 * as this one came out of, or we'll get into a fight
958 * over who claims what Ether address.
960 if (rt->rt_ifp == ifp) {
964 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
965 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
967 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr));
970 struct sockaddr_dl *sdl;
973 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
974 sdl = SDL(rt->rt_gateway);
975 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln);
979 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
980 memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
981 ah->ar_op = htons(ARPOP_REPLY);
982 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
983 switch (ifp->if_type) {
986 * May not be correct for types not explictly
987 * listed, but it is our best guess.
990 eh = (struct ether_header *)sa.sa_data;
991 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost);
992 eh->ether_type = htons(ETHERTYPE_ARP);
995 sa.sa_family = AF_UNSPEC;
996 sa.sa_len = sizeof sa;
997 ifp->if_output(ifp, m, &sa, NULL);
1003 arp_update_msghandler(struct netmsg *netmsg)
1005 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg;
1009 * This message handler will be called on all of the CPUs,
1010 * however, we only need to generate rtmsg on CPU0.
1012 arp_update_oncpu(msg->m, msg->saddr, msg->create,
1013 mycpuid == 0 ? RTL_REPORTMSG : RTL_DONTREPORT,
1016 nextcpu = mycpuid + 1;
1017 if (nextcpu < ncpus)
1018 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg);
1020 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0);
1028 * Free an arp entry. If the arp entry is actively referenced or represents
1029 * a static entry we only clear it back to an unresolved state, otherwise
1030 * we destroy the entry entirely.
1032 * Note that static entries are created when route add ... -interface is used
1033 * to create an interface route to a (direct) destination.
1036 arptfree(struct llinfo_arp *la)
1038 struct rtentry *rt = la->la_rt;
1039 struct sockaddr_dl *sdl;
1043 sdl = SDL(rt->rt_gateway);
1045 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) ||
1046 (rt->rt_flags & RTF_STATIC))) {
1048 la->la_preempt = la->la_asked = 0;
1049 rt->rt_flags &= ~RTF_REJECT;
1052 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL);
1056 * Lookup or enter a new address in arptab.
1058 static struct llinfo_arp *
1059 arplookup(in_addr_t addr, boolean_t create, boolean_t generate_report,
1063 struct sockaddr_inarp sin = { sizeof sin, AF_INET };
1064 const char *why = NULL;
1066 sin.sin_addr.s_addr = addr;
1067 sin.sin_other = proxy ? SIN_PROXY : 0;
1069 rt = _rtlookup((struct sockaddr *)&sin,
1070 generate_report, RTL_DOCLONE);
1072 rt = rtpurelookup((struct sockaddr *)&sin);
1078 if (rt->rt_flags & RTF_GATEWAY)
1079 why = "host is not on local network";
1080 else if (!(rt->rt_flags & RTF_LLINFO))
1081 why = "could not allocate llinfo";
1082 else if (rt->rt_gateway->sa_family != AF_LINK)
1083 why = "gateway route is not ours";
1087 log(LOG_DEBUG, "arplookup %s failed: %s\n",
1088 inet_ntoa(sin.sin_addr), why);
1090 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) {
1091 /* No references to this route. Purge it. */
1092 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway,
1093 rt_mask(rt), rt->rt_flags, NULL);
1097 return (rt->rt_llinfo);
1101 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
1103 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) {
1104 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr,
1105 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
1107 ifa->ifa_rtrequest = arp_rtrequest;
1108 ifa->ifa_flags |= RTF_CLONING;
1112 arp_iainit(struct ifnet *ifp, const struct in_addr *addr, const u_char *enaddr)
1114 if (addr->s_addr != INADDR_ANY)
1115 arprequest_async(ifp, addr, addr, enaddr);
1124 for (cpu = 0; cpu < ncpus2; cpu++)
1125 LIST_INIT(&llinfo_arp_list[cpu]);
1128 flags = NETISR_FLAG_MPSAFE;
1129 kprintf("arp: MPSAFE\n");
1131 flags = NETISR_FLAG_NOTMPSAFE;
1133 netisr_register(NETISR_ARP, cpu0_portfn, pktinfo_portfn_cpu0,
1137 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);