1 /*-
2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93
30 */
31
32 /*
33 * Ethernet address resolution protocol.
34 * TODO:
35 * add "inuse/lock" bit (or ref. count) along with valid bit
36 */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD: releng/8.1/sys/netinet/if_ether.c 207695 2010-05-06 06:44:19Z bz $");
40
41 #include "opt_inet.h"
42 #include "opt_carp.h"
43
44 #include <sys/param.h>
45 #include <sys/kernel.h>
46 #include <sys/queue.h>
47 #include <sys/sysctl.h>
48 #include <sys/systm.h>
49 #include <sys/mbuf.h>
50 #include <sys/malloc.h>
51 #include <sys/proc.h>
52 #include <sys/socket.h>
53 #include <sys/syslog.h>
54
55 #include <net/if.h>
56 #include <net/if_dl.h>
57 #include <net/if_types.h>
58 #include <net/netisr.h>
59 #include <net/if_llc.h>
60 #include <net/ethernet.h>
61 #include <net/route.h>
62 #include <net/vnet.h>
63
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
66 #include <net/if_llatbl.h>
67 #include <netinet/if_ether.h>
68
69 #include <net/if_arc.h>
70 #include <net/iso88025.h>
71
72 #ifdef DEV_CARP
73 #include <netinet/ip_carp.h>
74 #endif
75
76 #include <security/mac/mac_framework.h>
77
78 #define SIN(s) ((struct sockaddr_in *)s)
79 #define SDL(s) ((struct sockaddr_dl *)s)
80
81 SYSCTL_DECL(_net_link_ether);
82 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
83 SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
84
85 /* timer values */
86 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
87 * minutes */
88 static VNET_DEFINE(int, arp_maxtries) = 5;
89 VNET_DEFINE(int, useloopback) = 1; /* use loopback interface for
90 * local traffic */
91 static VNET_DEFINE(int, arp_proxyall) = 0;
92 static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for
93 * 20 seconds */
94 static VNET_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
95
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
102 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
103 &VNET_NAME(arpt_keep), 0,
104 "ARP entry lifetime in seconds");
105 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
106 &VNET_NAME(arp_maxtries), 0,
107 "ARP resolution attempts before returning error");
108 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
109 &VNET_NAME(useloopback), 0,
110 "Use the loopback interface for local traffic");
111 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
112 &VNET_NAME(arp_proxyall), 0,
113 "Enable proxy ARP for all suitable requests");
114 SYSCTL_VNET_STRUCT(_net_link_ether_arp, OID_AUTO, stats, CTLFLAG_RW,
115 &VNET_NAME(arpstat), arpstat,
116 "ARP statistics (struct arpstat, net/if_arp.h)");
117
118 static void arp_init(void);
119 void arprequest(struct ifnet *,
120 struct in_addr *, struct in_addr *, u_char *);
121 static void arpintr(struct mbuf *);
122 static void arptimer(void *);
123 #ifdef INET
124 static void in_arpinput(struct mbuf *);
125 #endif
126
127 static const struct netisr_handler arp_nh = {
128 .nh_name = "arp",
129 .nh_handler = arpintr,
130 .nh_proto = NETISR_ARP,
131 .nh_policy = NETISR_POLICY_SOURCE,
132 };
133
134 #ifdef AF_INET
135 void arp_ifscrub(struct ifnet *ifp, uint32_t addr);
136
137 /*
138 * called by in_ifscrub to remove entry from the table when
139 * the interface goes away
140 */
141 void
142 arp_ifscrub(struct ifnet *ifp, uint32_t addr)
143 {
144 struct sockaddr_in addr4;
145
146 bzero((void *)&addr4, sizeof(addr4));
147 addr4.sin_len = sizeof(addr4);
148 addr4.sin_family = AF_INET;
149 addr4.sin_addr.s_addr = addr;
150 CURVNET_SET(ifp->if_vnet);
151 IF_AFDATA_LOCK(ifp);
152 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR),
153 (struct sockaddr *)&addr4);
154 IF_AFDATA_UNLOCK(ifp);
155 CURVNET_RESTORE();
156 }
157 #endif
158
159 /*
160 * Timeout routine. Age arp_tab entries periodically.
161 */
162 static void
163 arptimer(void *arg)
164 {
165 struct ifnet *ifp;
166 struct llentry *lle = (struct llentry *)arg;
167
168 if (lle == NULL) {
169 panic("%s: NULL entry!\n", __func__);
170 return;
171 }
172 ifp = lle->lle_tbl->llt_ifp;
173 CURVNET_SET(ifp->if_vnet);
174 IF_AFDATA_LOCK(ifp);
175 LLE_WLOCK(lle);
176 if (lle->la_flags & LLE_STATIC)
177 LLE_WUNLOCK(lle);
178 else {
179 if (!callout_pending(&lle->la_timer) &&
180 callout_active(&lle->la_timer)) {
181 callout_stop(&lle->la_timer);
182 LLE_REMREF(lle);
183 (void) llentry_free(lle);
184 ARPSTAT_INC(timeouts);
185 }
186 #ifdef DIAGNOSTIC
187 else {
188 struct sockaddr *l3addr = L3_ADDR(lle);
189 log(LOG_INFO,
190 "arptimer issue: %p, IPv4 address: \"%s\"\n", lle,
191 inet_ntoa(
192 ((const struct sockaddr_in *)l3addr)->sin_addr));
193 }
194 #endif
195 }
196 IF_AFDATA_UNLOCK(ifp);
197 CURVNET_RESTORE();
198 }
199
200 /*
201 * Broadcast an ARP request. Caller specifies:
202 * - arp header source ip address
203 * - arp header target ip address
204 * - arp header source ethernet address
205 */
206 void
207 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip,
208 u_char *enaddr)
209 {
210 struct mbuf *m;
211 struct arphdr *ah;
212 struct sockaddr sa;
213
214 if (sip == NULL) {
215 /* XXX don't believe this can happen (or explain why) */
216 /*
217 * The caller did not supply a source address, try to find
218 * a compatible one among those assigned to this interface.
219 */
220 struct ifaddr *ifa;
221
222 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
223 if (!ifa->ifa_addr ||
224 ifa->ifa_addr->sa_family != AF_INET)
225 continue;
226 sip = &SIN(ifa->ifa_addr)->sin_addr;
227 if (0 == ((sip->s_addr ^ tip->s_addr) &
228 SIN(ifa->ifa_netmask)->sin_addr.s_addr) )
229 break; /* found it. */
230 }
231 if (sip == NULL) {
232 printf("%s: cannot find matching address\n", __func__);
233 return;
234 }
235 }
236
237 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
238 return;
239 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
240 2*ifp->if_data.ifi_addrlen;
241 m->m_pkthdr.len = m->m_len;
242 MH_ALIGN(m, m->m_len);
243 ah = mtod(m, struct arphdr *);
244 bzero((caddr_t)ah, m->m_len);
245 #ifdef MAC
246 mac_netinet_arp_send(ifp, m);
247 #endif
248 ah->ar_pro = htons(ETHERTYPE_IP);
249 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
250 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
251 ah->ar_op = htons(ARPOP_REQUEST);
252 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
253 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
254 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
255 sa.sa_family = AF_ARP;
256 sa.sa_len = 2;
257 m->m_flags |= M_BCAST;
258 (*ifp->if_output)(ifp, m, &sa, NULL);
259 ARPSTAT_INC(txrequests);
260 }
261
262 /*
263 * Resolve an IP address into an ethernet address.
264 * On input:
265 * ifp is the interface we use
266 * rt0 is the route to the final destination (possibly useless)
267 * m is the mbuf. May be NULL if we don't have a packet.
268 * dst is the next hop,
269 * desten is where we want the address.
270 *
271 * On success, desten is filled in and the function returns 0;
272 * If the packet must be held pending resolution, we return EWOULDBLOCK
273 * On other errors, we return the corresponding error code.
274 * Note that m_freem() handles NULL.
275 */
276 int
277 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
278 struct sockaddr *dst, u_char *desten, struct llentry **lle)
279 {
280 struct llentry *la = 0;
281 u_int flags = 0;
282 int error, renew;
283
284 *lle = NULL;
285 if (m != NULL) {
286 if (m->m_flags & M_BCAST) {
287 /* broadcast */
288 (void)memcpy(desten,
289 ifp->if_broadcastaddr, ifp->if_addrlen);
290 return (0);
291 }
292 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {
293 /* multicast */
294 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
295 return (0);
296 }
297 }
298 /* XXXXX
299 */
300 retry:
301 IF_AFDATA_RLOCK(ifp);
302 la = lla_lookup(LLTABLE(ifp), flags, dst);
303 IF_AFDATA_RUNLOCK(ifp);
304 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0)
305 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) {
306 flags |= (LLE_CREATE | LLE_EXCLUSIVE);
307 IF_AFDATA_WLOCK(ifp);
308 la = lla_lookup(LLTABLE(ifp), flags, dst);
309 IF_AFDATA_WUNLOCK(ifp);
310 }
311 if (la == NULL) {
312 if (flags & LLE_CREATE)
313 log(LOG_DEBUG,
314 "arpresolve: can't allocate llinfo for %s\n",
315 inet_ntoa(SIN(dst)->sin_addr));
316 m_freem(m);
317 return (EINVAL);
318 }
319
320 if ((la->la_flags & LLE_VALID) &&
321 ((la->la_flags & LLE_STATIC) || la->la_expire > time_second)) {
322 bcopy(&la->ll_addr, desten, ifp->if_addrlen);
323 /*
324 * If entry has an expiry time and it is approaching,
325 * see if we need to send an ARP request within this
326 * arpt_down interval.
327 */
328 if (!(la->la_flags & LLE_STATIC) &&
329 time_second + la->la_preempt > la->la_expire) {
330 arprequest(ifp, NULL,
331 &SIN(dst)->sin_addr, IF_LLADDR(ifp));
332
333 la->la_preempt--;
334 }
335
336 *lle = la;
337 error = 0;
338 goto done;
339 }
340
341 if (la->la_flags & LLE_STATIC) { /* should not happen! */
342 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n",
343 inet_ntoa(SIN(dst)->sin_addr));
344 m_freem(m);
345 error = EINVAL;
346 goto done;
347 }
348
349 renew = (la->la_asked == 0 || la->la_expire != time_second);
350 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) {
351 flags |= LLE_EXCLUSIVE;
352 LLE_RUNLOCK(la);
353 goto retry;
354 }
355 /*
356 * There is an arptab entry, but no ethernet address
357 * response yet. Replace the held mbuf with this
358 * latest one.
359 */
360 if (m != NULL) {
361 if (la->la_hold != NULL) {
362 m_freem(la->la_hold);
363 ARPSTAT_INC(dropped);
364 }
365 la->la_hold = m;
366 if (renew == 0 && (flags & LLE_EXCLUSIVE)) {
367 flags &= ~LLE_EXCLUSIVE;
368 LLE_DOWNGRADE(la);
369 }
370
371 }
372 /*
373 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
374 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
375 * if we have already sent arp_maxtries ARP requests. Retransmit the
376 * ARP request, but not faster than one request per second.
377 */
378 if (la->la_asked < V_arp_maxtries)
379 error = EWOULDBLOCK; /* First request. */
380 else
381 error = rt0 != NULL && (rt0->rt_flags & RTF_GATEWAY) ?
382 EHOSTUNREACH : EHOSTDOWN;
383
384 if (renew) {
385 int canceled;
386
387 LLE_ADDREF(la);
388 la->la_expire = time_second + V_arpt_down;
389 canceled = callout_reset(&la->la_timer, hz * V_arpt_down,
390 arptimer, la);
391 if (canceled)
392 LLE_REMREF(la);
393 la->la_asked++;
394 LLE_WUNLOCK(la);
395 arprequest(ifp, NULL, &SIN(dst)->sin_addr,
396 IF_LLADDR(ifp));
397 return (error);
398 }
399 done:
400 if (flags & LLE_EXCLUSIVE)
401 LLE_WUNLOCK(la);
402 else
403 LLE_RUNLOCK(la);
404 return (error);
405 }
406
407 /*
408 * Common length and type checks are done here,
409 * then the protocol-specific routine is called.
410 */
411 static void
412 arpintr(struct mbuf *m)
413 {
414 struct arphdr *ar;
415
416 if (m->m_len < sizeof(struct arphdr) &&
417 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
418 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
419 return;
420 }
421 ar = mtod(m, struct arphdr *);
422
423 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
424 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
425 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
426 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) {
427 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
428 (unsigned char *)&ar->ar_hrd, "");
429 m_freem(m);
430 return;
431 }
432
433 if (m->m_len < arphdr_len(ar)) {
434 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
435 log(LOG_ERR, "arp: runt packet\n");
436 m_freem(m);
437 return;
438 }
439 ar = mtod(m, struct arphdr *);
440 }
441
442 ARPSTAT_INC(received);
443 switch (ntohs(ar->ar_pro)) {
444 #ifdef INET
445 case ETHERTYPE_IP:
446 in_arpinput(m);
447 return;
448 #endif
449 }
450 m_freem(m);
451 }
452
453 #ifdef INET
454 /*
455 * ARP for Internet protocols on 10 Mb/s Ethernet.
456 * Algorithm is that given in RFC 826.
457 * In addition, a sanity check is performed on the sender
458 * protocol address, to catch impersonators.
459 * We no longer handle negotiations for use of trailer protocol:
460 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
461 * along with IP replies if we wanted trailers sent to us,
462 * and also sent them in response to IP replies.
463 * This allowed either end to announce the desire to receive
464 * trailer packets.
465 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
466 * but formerly didn't normally send requests.
467 */
468 static int log_arp_wrong_iface = 1;
469 static int log_arp_movements = 1;
470 static int log_arp_permanent_modify = 1;
471
472 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
473 &log_arp_wrong_iface, 0,
474 "log arp packets arriving on the wrong interface");
475 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
476 &log_arp_movements, 0,
477 "log arp replies from MACs different than the one in the cache");
478 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
479 &log_arp_permanent_modify, 0,
480 "log arp replies from MACs different than the one in the permanent arp entry");
481
482
483 static void
484 in_arpinput(struct mbuf *m)
485 {
486 struct arphdr *ah;
487 struct ifnet *ifp = m->m_pkthdr.rcvif;
488 struct llentry *la = NULL;
489 struct rtentry *rt;
490 struct ifaddr *ifa;
491 struct in_ifaddr *ia;
492 struct mbuf *hold;
493 struct sockaddr sa;
494 struct in_addr isaddr, itaddr, myaddr;
495 u_int8_t *enaddr = NULL;
496 int op, flags;
497 int req_len;
498 int bridged = 0, is_bridge = 0;
499 #ifdef DEV_CARP
500 int carp_match = 0;
501 #endif
502 struct sockaddr_in sin;
503 sin.sin_len = sizeof(struct sockaddr_in);
504 sin.sin_family = AF_INET;
505 sin.sin_addr.s_addr = 0;
506
507 if (ifp->if_bridge)
508 bridged = 1;
509 if (ifp->if_type == IFT_BRIDGE)
510 is_bridge = 1;
511
512 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
513 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
514 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
515 return;
516 }
517
518 ah = mtod(m, struct arphdr *);
519 op = ntohs(ah->ar_op);
520 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
521 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
522
523 if (op == ARPOP_REPLY)
524 ARPSTAT_INC(rxreplies);
525
526 /*
527 * For a bridge, we want to check the address irrespective
528 * of the receive interface. (This will change slightly
529 * when we have clusters of interfaces).
530 * If the interface does not match, but the recieving interface
531 * is part of carp, we call carp_iamatch to see if this is a
532 * request for the virtual host ip.
533 * XXX: This is really ugly!
534 */
535 IN_IFADDR_RLOCK();
536 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
537 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
538 ia->ia_ifp == ifp) &&
539 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
540 ifa_ref(&ia->ia_ifa);
541 IN_IFADDR_RUNLOCK();
542 goto match;
543 }
544 #ifdef DEV_CARP
545 if (ifp->if_carp != NULL &&
546 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) &&
547 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
548 carp_match = 1;
549 ifa_ref(&ia->ia_ifa);
550 IN_IFADDR_RUNLOCK();
551 goto match;
552 }
553 #endif
554 }
555 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
556 if (((bridged && ia->ia_ifp->if_bridge != NULL) ||
557 ia->ia_ifp == ifp) &&
558 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
559 ifa_ref(&ia->ia_ifa);
560 IN_IFADDR_RUNLOCK();
561 goto match;
562 }
563
564 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
565 (ia->ia_ifp->if_bridge == ifp->if_softc && \
566 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
567 addr == ia->ia_addr.sin_addr.s_addr)
568 /*
569 * Check the case when bridge shares its MAC address with
570 * some of its children, so packets are claimed by bridge
571 * itself (bridge_input() does it first), but they are really
572 * meant to be destined to the bridge member.
573 */
574 if (is_bridge) {
575 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
576 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
577 ifa_ref(&ia->ia_ifa);
578 ifp = ia->ia_ifp;
579 IN_IFADDR_RUNLOCK();
580 goto match;
581 }
582 }
583 }
584 #undef BDG_MEMBER_MATCHES_ARP
585 IN_IFADDR_RUNLOCK();
586
587 /*
588 * No match, use the first inet address on the receive interface
589 * as a dummy address for the rest of the function.
590 */
591 IF_ADDR_LOCK(ifp);
592 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
593 if (ifa->ifa_addr->sa_family == AF_INET) {
594 ia = ifatoia(ifa);
595 ifa_ref(ifa);
596 IF_ADDR_UNLOCK(ifp);
597 goto match;
598 }
599 IF_ADDR_UNLOCK(ifp);
600
601 /*
602 * If bridging, fall back to using any inet address.
603 */
604 IN_IFADDR_RLOCK();
605 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
606 IN_IFADDR_RUNLOCK();
607 goto drop;
608 }
609 ifa_ref(&ia->ia_ifa);
610 IN_IFADDR_RUNLOCK();
611 match:
612 if (!enaddr)
613 enaddr = (u_int8_t *)IF_LLADDR(ifp);
614 myaddr = ia->ia_addr.sin_addr;
615 ifa_free(&ia->ia_ifa);
616 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
617 goto drop; /* it's from me, ignore it. */
618 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
619 log(LOG_ERR,
620 "arp: link address is broadcast for IP address %s!\n",
621 inet_ntoa(isaddr));
622 goto drop;
623 }
624 /*
625 * Warn if another host is using the same IP address, but only if the
626 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
627 * case we suppress the warning to avoid false positive complaints of
628 * potential misconfiguration.
629 */
630 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
631 log(LOG_ERR,
632 "arp: %*D is using my IP address %s on %s!\n",
633 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
634 inet_ntoa(isaddr), ifp->if_xname);
635 itaddr = myaddr;
636 ARPSTAT_INC(dupips);
637 goto reply;
638 }
639 if (ifp->if_flags & IFF_STATICARP)
640 goto reply;
641
642 bzero(&sin, sizeof(sin));
643 sin.sin_len = sizeof(struct sockaddr_in);
644 sin.sin_family = AF_INET;
645 sin.sin_addr = isaddr;
646 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0;
647 flags |= LLE_EXCLUSIVE;
648 IF_AFDATA_LOCK(ifp);
649 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin);
650 IF_AFDATA_UNLOCK(ifp);
651 if (la != NULL) {
652 /* the following is not an error when doing bridging */
653 if (!bridged && la->lle_tbl->llt_ifp != ifp
654 #ifdef DEV_CARP
655 && (ifp->if_type != IFT_CARP || !carp_match)
656 #endif
657 ) {
658 if (log_arp_wrong_iface)
659 log(LOG_ERR, "arp: %s is on %s "
660 "but got reply from %*D on %s\n",
661 inet_ntoa(isaddr),
662 la->lle_tbl->llt_ifp->if_xname,
663 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
664 ifp->if_xname);
665 LLE_WUNLOCK(la);
666 goto reply;
667 }
668 if ((la->la_flags & LLE_VALID) &&
669 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) {
670 if (la->la_flags & LLE_STATIC) {
671 LLE_WUNLOCK(la);
672 log(LOG_ERR,
673 "arp: %*D attempts to modify permanent "
674 "entry for %s on %s\n",
675 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
676 inet_ntoa(isaddr), ifp->if_xname);
677 goto reply;
678 }
679 if (log_arp_movements) {
680 log(LOG_INFO, "arp: %s moved from %*D "
681 "to %*D on %s\n",
682 inet_ntoa(isaddr),
683 ifp->if_addrlen,
684 (u_char *)&la->ll_addr, ":",
685 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
686 ifp->if_xname);
687 }
688 }
689
690 if (ifp->if_addrlen != ah->ar_hln) {
691 LLE_WUNLOCK(la);
692 log(LOG_WARNING,
693 "arp from %*D: addr len: new %d, i/f %d (ignored)",
694 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
695 ah->ar_hln, ifp->if_addrlen);
696 goto reply;
697 }
698 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen);
699 la->la_flags |= LLE_VALID;
700
701 if (!(la->la_flags & LLE_STATIC)) {
702 int canceled;
703
704 LLE_ADDREF(la);
705 la->la_expire = time_second + V_arpt_keep;
706 canceled = callout_reset(&la->la_timer,
707 hz * V_arpt_keep, arptimer, la);
708 if (canceled)
709 LLE_REMREF(la);
710 }
711 la->la_asked = 0;
712 la->la_preempt = V_arp_maxtries;
713 hold = la->la_hold;
714 if (hold != NULL) {
715 la->la_hold = NULL;
716 memcpy(&sa, L3_ADDR(la), sizeof(sa));
717 }
718 LLE_WUNLOCK(la);
719 if (hold != NULL)
720 (*ifp->if_output)(ifp, hold, &sa, NULL);
721 }
722 reply:
723 if (op != ARPOP_REQUEST)
724 goto drop;
725 ARPSTAT_INC(rxrequests);
726
727 if (itaddr.s_addr == myaddr.s_addr) {
728 /* Shortcut.. the receiving interface is the target. */
729 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
730 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
731 } else {
732 struct llentry *lle = NULL;
733
734 sin.sin_addr = itaddr;
735 IF_AFDATA_LOCK(ifp);
736 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
737 IF_AFDATA_UNLOCK(ifp);
738
739 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
740 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
741 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln);
742 LLE_RUNLOCK(lle);
743 } else {
744
745 if (lle != NULL)
746 LLE_RUNLOCK(lle);
747
748 if (!V_arp_proxyall)
749 goto drop;
750
751 sin.sin_addr = itaddr;
752 /* XXX MRT use table 0 for arp reply */
753 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
754 if (!rt)
755 goto drop;
756
757 /*
758 * Don't send proxies for nodes on the same interface
759 * as this one came out of, or we'll get into a fight
760 * over who claims what Ether address.
761 */
762 if (!rt->rt_ifp || rt->rt_ifp == ifp) {
763 RTFREE_LOCKED(rt);
764 goto drop;
765 }
766 RTFREE_LOCKED(rt);
767
768 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
769 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
770
771 /*
772 * Also check that the node which sent the ARP packet
773 * is on the the interface we expect it to be on. This
774 * avoids ARP chaos if an interface is connected to the
775 * wrong network.
776 */
777 sin.sin_addr = isaddr;
778
779 /* XXX MRT use table 0 for arp checks */
780 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0);
781 if (!rt)
782 goto drop;
783 if (rt->rt_ifp != ifp) {
784 log(LOG_INFO, "arp_proxy: ignoring request"
785 " from %s via %s, expecting %s\n",
786 inet_ntoa(isaddr), ifp->if_xname,
787 rt->rt_ifp->if_xname);
788 RTFREE_LOCKED(rt);
789 goto drop;
790 }
791 RTFREE_LOCKED(rt);
792
793 #ifdef DEBUG_PROXY
794 printf("arp: proxying for %s\n",
795 inet_ntoa(itaddr));
796 #endif
797 }
798 }
799
800 if (itaddr.s_addr == myaddr.s_addr &&
801 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
802 /* RFC 3927 link-local IPv4; always reply by broadcast. */
803 #ifdef DEBUG_LINKLOCAL
804 printf("arp: sending reply for link-local addr %s\n",
805 inet_ntoa(itaddr));
806 #endif
807 m->m_flags |= M_BCAST;
808 m->m_flags &= ~M_MCAST;
809 } else {
810 /* default behaviour; never reply by broadcast. */
811 m->m_flags &= ~(M_BCAST|M_MCAST);
812 }
813 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
814 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
815 ah->ar_op = htons(ARPOP_REPLY);
816 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
817 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
818 m->m_pkthdr.len = m->m_len;
819 sa.sa_family = AF_ARP;
820 sa.sa_len = 2;
821 (*ifp->if_output)(ifp, m, &sa, NULL);
822 ARPSTAT_INC(txreplies);
823 return;
824
825 drop:
826 m_freem(m);
827 }
828 #endif
829
830 void
831 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
832 {
833 struct llentry *lle;
834
835 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) {
836 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
837 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
838 /*
839 * interface address is considered static entry
840 * because the output of the arp utility shows
841 * that L2 entry as permanent
842 */
843 IF_AFDATA_LOCK(ifp);
844 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC),
845 (struct sockaddr *)IA_SIN(ifa));
846 IF_AFDATA_UNLOCK(ifp);
847 if (lle == NULL)
848 log(LOG_INFO, "arp_ifinit: cannot create arp "
849 "entry for interface address\n");
850 else
851 LLE_RUNLOCK(lle);
852 }
853 ifa->ifa_rtrequest = NULL;
854 }
855
856 void
857 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr)
858 {
859 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
860 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
861 &IA_SIN(ifa)->sin_addr, enaddr);
862 ifa->ifa_rtrequest = NULL;
863 }
864
865 static void
866 arp_init(void)
867 {
868
869 netisr_register(&arp_nh);
870 }
871 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
Cache object: c2cf779e1de305a07bf1cc4fbce9dd0f
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