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 * $FreeBSD: releng/5.4/sys/netinet/if_ether.c 145335 2005-04-20 19:11:07Z cvs2svn $
31 */
32
33 /*
34 * Ethernet address resolution protocol.
35 * TODO:
36 * add "inuse/lock" bit (or ref. count) along with valid bit
37 */
38
39 #include "opt_inet.h"
40 #include "opt_bdg.h"
41 #include "opt_mac.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/mac.h>
50 #include <sys/mbuf.h>
51 #include <sys/malloc.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/route.h>
59 #include <net/netisr.h>
60 #include <net/if_llc.h>
61 #include <net/ethernet.h>
62 #include <net/bridge.h>
63
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
66 #include <netinet/if_ether.h>
67
68 #include <net/if_arc.h>
69 #include <net/iso88025.h>
70
71 #ifdef DEV_CARP
72 #include <netinet/ip_carp.h>
73 #endif
74
75 #define SIN(s) ((struct sockaddr_in *)s)
76 #define SDL(s) ((struct sockaddr_dl *)s)
77
78 SYSCTL_DECL(_net_link_ether);
79 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
80
81 /* timer values */
82 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */
83 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
84 static int arpt_down = 20; /* once declared down, don't send for 20 sec */
85
86 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
87 &arpt_prune, 0, "");
88 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
89 &arpt_keep, 0, "");
90 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
91 &arpt_down, 0, "");
92
93 #define rt_expire rt_rmx.rmx_expire
94
95 struct llinfo_arp {
96 LIST_ENTRY(llinfo_arp) la_le;
97 struct rtentry *la_rt;
98 struct mbuf *la_hold; /* last packet until resolved/timeout */
99 u_short la_preempt; /* countdown for pre-expiry arps */
100 u_short la_asked; /* #times we QUERIED following expiration */
101 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */
102 };
103
104 static LIST_HEAD(, llinfo_arp) llinfo_arp;
105
106 static struct ifqueue arpintrq;
107 static int arp_allocated;
108
109 static int arp_maxtries = 5;
110 static int useloopback = 1; /* use loopback interface for local traffic */
111 static int arp_proxyall = 0;
112 static struct callout arp_callout;
113
114 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
115 &arp_maxtries, 0, "");
116 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
117 &useloopback, 0, "");
118 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
119 &arp_proxyall, 0, "");
120
121 static void arp_init(void);
122 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *);
123 static void arprequest(struct ifnet *,
124 struct in_addr *, struct in_addr *, u_char *);
125 static void arpintr(struct mbuf *);
126 static void arptfree(struct llinfo_arp *);
127 static void arptimer(void *);
128 static struct llinfo_arp
129 *arplookup(u_long, int, int);
130 #ifdef INET
131 static void in_arpinput(struct mbuf *);
132 #endif
133
134 /*
135 * Timeout routine. Age arp_tab entries periodically.
136 */
137 /* ARGSUSED */
138 static void
139 arptimer(ignored_arg)
140 void *ignored_arg;
141 {
142 struct llinfo_arp *la, *ola;
143
144 RADIX_NODE_HEAD_LOCK(rt_tables[AF_INET]);
145 la = LIST_FIRST(&llinfo_arp);
146 while (la != NULL) {
147 struct rtentry *rt = la->la_rt;
148 ola = la;
149 la = LIST_NEXT(la, la_le);
150 if (rt->rt_expire && rt->rt_expire <= time_second)
151 arptfree(ola); /* timer has expired, clear */
152 }
153 RADIX_NODE_HEAD_UNLOCK(rt_tables[AF_INET]);
154
155 callout_reset(&arp_callout, arpt_prune * hz, arptimer, NULL);
156 }
157
158 /*
159 * Parallel to llc_rtrequest.
160 */
161 static void
162 arp_rtrequest(req, rt, info)
163 int req;
164 struct rtentry *rt;
165 struct rt_addrinfo *info;
166 {
167 struct sockaddr *gate;
168 struct llinfo_arp *la;
169 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
170 struct in_ifaddr *ia;
171 struct ifaddr *ifa;
172
173 RT_LOCK_ASSERT(rt);
174
175 if (rt->rt_flags & RTF_GATEWAY)
176 return;
177 gate = rt->rt_gateway;
178 la = (struct llinfo_arp *)rt->rt_llinfo;
179 switch (req) {
180
181 case RTM_ADD:
182 /*
183 * XXX: If this is a manually added route to interface
184 * such as older version of routed or gated might provide,
185 * restore cloning bit.
186 */
187 if ((rt->rt_flags & RTF_HOST) == 0 &&
188 rt_mask(rt) != NULL &&
189 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
190 rt->rt_flags |= RTF_CLONING;
191 if (rt->rt_flags & RTF_CLONING) {
192 /*
193 * Case 1: This route should come from a route to iface.
194 */
195 rt_setgate(rt, rt_key(rt),
196 (struct sockaddr *)&null_sdl);
197 gate = rt->rt_gateway;
198 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
199 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
200 rt->rt_expire = time_second;
201 break;
202 }
203 /* Announce a new entry if requested. */
204 if (rt->rt_flags & RTF_ANNOUNCE)
205 arprequest(rt->rt_ifp,
206 &SIN(rt_key(rt))->sin_addr,
207 &SIN(rt_key(rt))->sin_addr,
208 (u_char *)LLADDR(SDL(gate)));
209 /*FALLTHROUGH*/
210 case RTM_RESOLVE:
211 if (gate->sa_family != AF_LINK ||
212 gate->sa_len < sizeof(null_sdl)) {
213 log(LOG_DEBUG, "%s: bad gateway %s%s\n", __func__,
214 inet_ntoa(SIN(rt_key(rt))->sin_addr),
215 (gate->sa_family != AF_LINK) ?
216 " (!AF_LINK)": "");
217 break;
218 }
219 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
220 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
221 if (la != 0)
222 break; /* This happens on a route change */
223 /*
224 * Case 2: This route may come from cloning, or a manual route
225 * add with a LL address.
226 */
227 R_Zalloc(la, struct llinfo_arp *, sizeof(*la));
228 rt->rt_llinfo = (caddr_t)la;
229 if (la == 0) {
230 log(LOG_DEBUG, "%s: malloc failed\n", __func__);
231 break;
232 }
233 arp_allocated++;
234 la->la_rt = rt;
235 rt->rt_flags |= RTF_LLINFO;
236 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]);
237 LIST_INSERT_HEAD(&llinfo_arp, la, la_le);
238
239 #ifdef INET
240 /*
241 * This keeps the multicast addresses from showing up
242 * in `arp -a' listings as unresolved. It's not actually
243 * functional. Then the same for broadcast.
244 */
245 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) &&
246 rt->rt_ifp->if_type != IFT_ARCNET) {
247 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
248 LLADDR(SDL(gate)));
249 SDL(gate)->sdl_alen = 6;
250 rt->rt_expire = 0;
251 }
252 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) {
253 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr,
254 rt->rt_ifp->if_addrlen);
255 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen;
256 rt->rt_expire = 0;
257 }
258 #endif
259
260 TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) {
261 if (ia->ia_ifp == rt->rt_ifp &&
262 SIN(rt_key(rt))->sin_addr.s_addr ==
263 (IA_SIN(ia))->sin_addr.s_addr)
264 break;
265 }
266 if (ia) {
267 /*
268 * This test used to be
269 * if (loif.if_flags & IFF_UP)
270 * It allowed local traffic to be forced
271 * through the hardware by configuring the loopback down.
272 * However, it causes problems during network configuration
273 * for boards that can't receive packets they send.
274 * It is now necessary to clear "useloopback" and remove
275 * the route to force traffic out to the hardware.
276 */
277 rt->rt_expire = 0;
278 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)),
279 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen);
280 if (useloopback)
281 rt->rt_ifp = loif;
282
283 /*
284 * make sure to set rt->rt_ifa to the interface
285 * address we are using, otherwise we will have trouble
286 * with source address selection.
287 */
288 ifa = &ia->ia_ifa;
289 if (ifa != rt->rt_ifa) {
290 IFAFREE(rt->rt_ifa);
291 IFAREF(ifa);
292 rt->rt_ifa = ifa;
293 }
294 }
295 break;
296
297 case RTM_DELETE:
298 if (la == 0)
299 break;
300 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]);
301 LIST_REMOVE(la, la_le);
302 rt->rt_llinfo = 0;
303 rt->rt_flags &= ~RTF_LLINFO;
304 if (la->la_hold)
305 m_freem(la->la_hold);
306 Free((caddr_t)la);
307 }
308 }
309
310 /*
311 * Broadcast an ARP request. Caller specifies:
312 * - arp header source ip address
313 * - arp header target ip address
314 * - arp header source ethernet address
315 */
316 static void
317 arprequest(ifp, sip, tip, enaddr)
318 struct ifnet *ifp;
319 struct in_addr *sip, *tip;
320 u_char *enaddr;
321 {
322 struct mbuf *m;
323 struct arphdr *ah;
324 struct sockaddr sa;
325
326 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
327 return;
328 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) +
329 2*ifp->if_data.ifi_addrlen;
330 m->m_pkthdr.len = m->m_len;
331 MH_ALIGN(m, m->m_len);
332 ah = mtod(m, struct arphdr *);
333 bzero((caddr_t)ah, m->m_len);
334 #ifdef MAC
335 mac_create_mbuf_linklayer(ifp, m);
336 #endif
337 ah->ar_pro = htons(ETHERTYPE_IP);
338 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
339 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
340 ah->ar_op = htons(ARPOP_REQUEST);
341 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln);
342 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln);
343 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln);
344 sa.sa_family = AF_ARP;
345 sa.sa_len = 2;
346 m->m_flags |= M_BCAST;
347 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
348
349 return;
350 }
351
352 /*
353 * Resolve an IP address into an ethernet address.
354 * On input:
355 * ifp is the interface we use
356 * dst is the next hop,
357 * rt0 is the route to the final destination (possibly useless)
358 * m is the mbuf
359 * desten is where we want the address.
360 *
361 * On success, desten is filled in and the function returns 0;
362 * If the packet must be held pending resolution, we return EWOULDBLOCK
363 * On other errors, we return the corresponding error code.
364 */
365 int
366 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
367 struct sockaddr *dst, u_char *desten)
368 {
369 struct llinfo_arp *la = 0;
370 struct sockaddr_dl *sdl;
371 int error;
372 struct rtentry *rt;
373
374 error = rt_check(&rt, &rt0, dst);
375 if (error) {
376 m_freem(m);
377 return error;
378 }
379
380 if (m->m_flags & M_BCAST) { /* broadcast */
381 (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen);
382 return (0);
383 }
384 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */
385 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
386 return (0);
387 }
388 if (rt)
389 la = (struct llinfo_arp *)rt->rt_llinfo;
390 if (la == 0) {
391 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0);
392 if (la)
393 rt = la->la_rt;
394 }
395 if (la == 0 || rt == 0) {
396 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n",
397 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "",
398 rt ? "rt" : "");
399 m_freem(m);
400 return (EINVAL); /* XXX */
401 }
402 sdl = SDL(rt->rt_gateway);
403 /*
404 * Check the address family and length is valid, the address
405 * is resolved; otherwise, try to resolve.
406 */
407 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) &&
408 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
409 /*
410 * If entry has an expiry time and it is approaching,
411 * see if we need to send an ARP request within this
412 * arpt_down interval.
413 */
414 if ((rt->rt_expire != 0) &&
415 (time_second + la->la_preempt > rt->rt_expire)) {
416 arprequest(ifp,
417 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
418 &SIN(dst)->sin_addr,
419 IF_LLADDR(ifp));
420 la->la_preempt--;
421 }
422
423 bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
424 return (0);
425 }
426 /*
427 * If ARP is disabled or static on this interface, stop.
428 * XXX
429 * Probably should not allocate empty llinfo struct if we are
430 * not going to be sending out an arp request.
431 */
432 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) {
433 m_freem(m);
434 return (EINVAL);
435 }
436 /*
437 * There is an arptab entry, but no ethernet address
438 * response yet. Replace the held mbuf with this
439 * latest one.
440 */
441 if (la->la_hold)
442 m_freem(la->la_hold);
443 la->la_hold = m;
444 if (rt->rt_expire) {
445 RT_LOCK(rt);
446 rt->rt_flags &= ~RTF_REJECT;
447 if (la->la_asked == 0 || rt->rt_expire != time_second) {
448 rt->rt_expire = time_second;
449 if (la->la_asked++ < arp_maxtries) {
450 arprequest(ifp,
451 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
452 &SIN(dst)->sin_addr,
453 IF_LLADDR(ifp));
454 } else {
455 rt->rt_flags |= RTF_REJECT;
456 rt->rt_expire += arpt_down;
457 la->la_asked = 0;
458 la->la_preempt = arp_maxtries;
459 }
460
461 }
462 RT_UNLOCK(rt);
463 }
464 return (EWOULDBLOCK);
465 }
466
467 /*
468 * Common length and type checks are done here,
469 * then the protocol-specific routine is called.
470 */
471 static void
472 arpintr(struct mbuf *m)
473 {
474 struct arphdr *ar;
475
476 if (m->m_len < sizeof(struct arphdr) &&
477 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
478 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
479 return;
480 }
481 ar = mtod(m, struct arphdr *);
482
483 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER &&
484 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 &&
485 ntohs(ar->ar_hrd) != ARPHRD_ARCNET &&
486 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) {
487 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n",
488 (unsigned char *)&ar->ar_hrd, "");
489 m_freem(m);
490 return;
491 }
492
493 if (m->m_len < arphdr_len(ar)) {
494 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) {
495 log(LOG_ERR, "arp: runt packet\n");
496 m_freem(m);
497 return;
498 }
499 ar = mtod(m, struct arphdr *);
500 }
501
502 switch (ntohs(ar->ar_pro)) {
503 #ifdef INET
504 case ETHERTYPE_IP:
505 in_arpinput(m);
506 return;
507 #endif
508 }
509 m_freem(m);
510 }
511
512 #ifdef INET
513 /*
514 * ARP for Internet protocols on 10 Mb/s Ethernet.
515 * Algorithm is that given in RFC 826.
516 * In addition, a sanity check is performed on the sender
517 * protocol address, to catch impersonators.
518 * We no longer handle negotiations for use of trailer protocol:
519 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
520 * along with IP replies if we wanted trailers sent to us,
521 * and also sent them in response to IP replies.
522 * This allowed either end to announce the desire to receive
523 * trailer packets.
524 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
525 * but formerly didn't normally send requests.
526 */
527 static int log_arp_wrong_iface = 1;
528 static int log_arp_movements = 1;
529
530 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
531 &log_arp_wrong_iface, 0,
532 "log arp packets arriving on the wrong interface");
533 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
534 &log_arp_movements, 0,
535 "log arp replies from MACs different than the one in the cache");
536
537
538 static void
539 in_arpinput(m)
540 struct mbuf *m;
541 {
542 struct arphdr *ah;
543 struct ifnet *ifp = m->m_pkthdr.rcvif;
544 struct iso88025_header *th = (struct iso88025_header *)0;
545 struct iso88025_sockaddr_dl_data *trld;
546 struct llinfo_arp *la = 0;
547 struct rtentry *rt;
548 struct ifaddr *ifa;
549 struct in_ifaddr *ia;
550 struct sockaddr_dl *sdl;
551 struct sockaddr sa;
552 struct in_addr isaddr, itaddr, myaddr;
553 u_int8_t *enaddr = NULL;
554 int op, rif_len;
555 int req_len;
556 #ifdef DEV_CARP
557 int carp_match = 0;
558 #endif
559
560 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
561 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
562 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
563 return;
564 }
565
566 ah = mtod(m, struct arphdr *);
567 op = ntohs(ah->ar_op);
568 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
569 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
570
571 /*
572 * For a bridge, we want to check the address irrespective
573 * of the receive interface. (This will change slightly
574 * when we have clusters of interfaces).
575 * If the interface does not match, but the recieving interface
576 * is part of carp, we call carp_iamatch to see if this is a
577 * request for the virtual host ip.
578 * XXX: This is really ugly!
579 */
580 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
581 if ((do_bridge || (ia->ia_ifp == ifp)) &&
582 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr)
583 goto match;
584 #ifdef DEV_CARP
585 if (ifp->if_carp != NULL &&
586 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) &&
587 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
588 carp_match = 1;
589 goto match;
590 }
591 #endif
592 }
593 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
594 if ((do_bridge || (ia->ia_ifp == ifp)) &&
595 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)
596 goto match;
597 /*
598 * No match, use the first inet address on the receive interface
599 * as a dummy address for the rest of the function.
600 */
601 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
602 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
603 ia = ifatoia(ifa);
604 goto match;
605 }
606 /*
607 * If bridging, fall back to using any inet address.
608 */
609 if (!do_bridge || (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL)
610 goto drop;
611 match:
612 if (!enaddr)
613 enaddr = (u_int8_t *)IF_LLADDR(ifp);
614 myaddr = ia->ia_addr.sin_addr;
615 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
616 goto drop; /* it's from me, ignore it. */
617 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
618 log(LOG_ERR,
619 "arp: link address is broadcast for IP address %s!\n",
620 inet_ntoa(isaddr));
621 goto drop;
622 }
623 /*
624 * Warn if another host is using the same IP address, but only if the
625 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
626 * case we suppress the warning to avoid false positive complaints of
627 * potential misconfiguration.
628 */
629 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
630 log(LOG_ERR,
631 "arp: %*D is using my IP address %s!\n",
632 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
633 inet_ntoa(isaddr));
634 itaddr = myaddr;
635 goto reply;
636 }
637 if (ifp->if_flags & IFF_STATICARP)
638 goto reply;
639 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);
640 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
641 /* the following is not an error when doing bridging */
642 if (!do_bridge && rt->rt_ifp != ifp
643 #ifdef DEV_CARP
644 && (ifp->if_type != IFT_CARP || !carp_match)
645 #endif
646 ) {
647 if (log_arp_wrong_iface)
648 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n",
649 inet_ntoa(isaddr),
650 rt->rt_ifp->if_xname,
651 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
652 ifp->if_xname);
653 goto reply;
654 }
655 if (sdl->sdl_alen &&
656 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) {
657 if (rt->rt_expire) {
658 if (log_arp_movements)
659 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n",
660 inet_ntoa(isaddr),
661 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":",
662 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
663 ifp->if_xname);
664 } else {
665 log(LOG_ERR,
666 "arp: %*D attempts to modify permanent entry for %s on %s\n",
667 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
668 inet_ntoa(isaddr), ifp->if_xname);
669 goto reply;
670 }
671 }
672 /*
673 * sanity check for the address length.
674 * XXX this does not work for protocols with variable address
675 * length. -is
676 */
677 if (sdl->sdl_alen &&
678 sdl->sdl_alen != ah->ar_hln) {
679 log(LOG_WARNING,
680 "arp from %*D: new addr len %d, was %d",
681 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
682 ah->ar_hln, sdl->sdl_alen);
683 }
684 if (ifp->if_addrlen != ah->ar_hln) {
685 log(LOG_WARNING,
686 "arp from %*D: addr len: new %d, i/f %d (ignored)",
687 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
688 ah->ar_hln, ifp->if_addrlen);
689 goto reply;
690 }
691 (void)memcpy(LLADDR(sdl), ar_sha(ah),
692 sdl->sdl_alen = ah->ar_hln);
693 /*
694 * If we receive an arp from a token-ring station over
695 * a token-ring nic then try to save the source
696 * routing info.
697 */
698 if (ifp->if_type == IFT_ISO88025) {
699 th = (struct iso88025_header *)m->m_pkthdr.header;
700 trld = SDL_ISO88025(sdl);
701 rif_len = TR_RCF_RIFLEN(th->rcf);
702 if ((th->iso88025_shost[0] & TR_RII) &&
703 (rif_len > 2)) {
704 trld->trld_rcf = th->rcf;
705 trld->trld_rcf ^= htons(TR_RCF_DIR);
706 memcpy(trld->trld_route, th->rd, rif_len - 2);
707 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK);
708 /*
709 * Set up source routing information for
710 * reply packet (XXX)
711 */
712 m->m_data -= rif_len;
713 m->m_len += rif_len;
714 m->m_pkthdr.len += rif_len;
715 } else {
716 th->iso88025_shost[0] &= ~TR_RII;
717 trld->trld_rcf = 0;
718 }
719 m->m_data -= 8;
720 m->m_len += 8;
721 m->m_pkthdr.len += 8;
722 th->rcf = trld->trld_rcf;
723 }
724 RT_LOCK(rt);
725 if (rt->rt_expire)
726 rt->rt_expire = time_second + arpt_keep;
727 rt->rt_flags &= ~RTF_REJECT;
728 RT_UNLOCK(rt);
729 la->la_asked = 0;
730 la->la_preempt = arp_maxtries;
731 if (la->la_hold) {
732 (*ifp->if_output)(ifp, la->la_hold, rt_key(rt), rt);
733 la->la_hold = 0;
734 }
735 }
736 reply:
737 if (op != ARPOP_REQUEST)
738 goto drop;
739 if (itaddr.s_addr == myaddr.s_addr) {
740 /* I am the target */
741 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
742 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
743 } else {
744 la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
745 if (la == NULL) {
746 struct sockaddr_in sin;
747
748 if (!arp_proxyall)
749 goto drop;
750
751 bzero(&sin, sizeof sin);
752 sin.sin_family = AF_INET;
753 sin.sin_len = sizeof sin;
754 sin.sin_addr = itaddr;
755
756 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
757 if (!rt)
758 goto drop;
759 /*
760 * Don't send proxies for nodes on the same interface
761 * as this one came out of, or we'll get into a fight
762 * over who claims what Ether address.
763 */
764 if (rt->rt_ifp == ifp) {
765 rtfree(rt);
766 goto drop;
767 }
768 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
769 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
770 rtfree(rt);
771
772 /*
773 * Also check that the node which sent the ARP packet
774 * is on the the interface we expect it to be on. This
775 * avoids ARP chaos if an interface is connected to the
776 * wrong network.
777 */
778 sin.sin_addr = isaddr;
779
780 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
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(rt);
789 goto drop;
790 }
791 rtfree(rt);
792
793 #ifdef DEBUG_PROXY
794 printf("arp: proxying for %s\n",
795 inet_ntoa(itaddr));
796 #endif
797 } else {
798 rt = la->la_rt;
799 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
800 sdl = SDL(rt->rt_gateway);
801 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln);
802 }
803 }
804
805 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
806 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
807 ah->ar_op = htons(ARPOP_REPLY);
808 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
809 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */
810 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
811 m->m_pkthdr.len = m->m_len;
812 sa.sa_family = AF_ARP;
813 sa.sa_len = 2;
814 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
815 return;
816
817 drop:
818 m_freem(m);
819 }
820 #endif
821
822 /*
823 * Free an arp entry.
824 */
825 static void
826 arptfree(la)
827 struct llinfo_arp *la;
828 {
829 struct rtentry *rt = la->la_rt;
830 struct sockaddr_dl *sdl;
831
832 if (rt == 0)
833 panic("arptfree");
834 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
835 sdl->sdl_family == AF_LINK) {
836 sdl->sdl_alen = 0;
837 la->la_preempt = la->la_asked = 0;
838 RT_LOCK(rt); /* XXX needed or move higher? */
839 rt->rt_flags &= ~RTF_REJECT;
840 RT_UNLOCK(rt);
841 return;
842 }
843 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
844 0, (struct rtentry **)0);
845 }
846 /*
847 * Lookup or enter a new address in arptab.
848 */
849 static struct llinfo_arp *
850 arplookup(addr, create, proxy)
851 u_long addr;
852 int create, proxy;
853 {
854 struct rtentry *rt;
855 struct sockaddr_inarp sin;
856 const char *why = 0;
857
858 bzero(&sin, sizeof(sin));
859 sin.sin_len = sizeof(sin);
860 sin.sin_family = AF_INET;
861 sin.sin_addr.s_addr = addr;
862 if (proxy)
863 sin.sin_other = SIN_PROXY;
864 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL);
865 if (rt == 0)
866 return (0);
867
868 if (rt->rt_flags & RTF_GATEWAY)
869 why = "host is not on local network";
870 else if ((rt->rt_flags & RTF_LLINFO) == 0)
871 why = "could not allocate llinfo";
872 else if (rt->rt_gateway->sa_family != AF_LINK)
873 why = "gateway route is not ours";
874
875 if (why) {
876 #define ISDYNCLONE(_rt) \
877 (((_rt)->rt_flags & (RTF_STATIC | RTF_WASCLONED)) == RTF_WASCLONED)
878 if (create)
879 log(LOG_DEBUG, "arplookup %s failed: %s\n",
880 inet_ntoa(sin.sin_addr), why);
881 /*
882 * If there are no references to this Layer 2 route,
883 * and it is a cloned route, and not static, and
884 * arplookup() is creating the route, then purge
885 * it from the routing table as it is probably bogus.
886 */
887 if (rt->rt_refcnt == 1 && ISDYNCLONE(rt))
888 rtexpunge(rt);
889 RTFREE_LOCKED(rt);
890 return (0);
891 #undef ISDYNCLONE
892 } else {
893 RT_REMREF(rt);
894 RT_UNLOCK(rt);
895 return ((struct llinfo_arp *)rt->rt_llinfo);
896 }
897 }
898
899 void
900 arp_ifinit(ifp, ifa)
901 struct ifnet *ifp;
902 struct ifaddr *ifa;
903 {
904 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
905 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
906 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
907 ifa->ifa_rtrequest = arp_rtrequest;
908 ifa->ifa_flags |= RTF_CLONING;
909 }
910
911 void
912 arp_ifinit2(ifp, ifa, enaddr)
913 struct ifnet *ifp;
914 struct ifaddr *ifa;
915 u_char *enaddr;
916 {
917 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
918 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
919 &IA_SIN(ifa)->sin_addr, enaddr);
920 ifa->ifa_rtrequest = arp_rtrequest;
921 ifa->ifa_flags |= RTF_CLONING;
922 }
923
924 static void
925 arp_init(void)
926 {
927
928 arpintrq.ifq_maxlen = 50;
929 mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF);
930 LIST_INIT(&llinfo_arp);
931 callout_init(&arp_callout, CALLOUT_MPSAFE);
932 netisr_register(NETISR_ARP, arpintr, &arpintrq, NETISR_MPSAFE);
933 callout_reset(&arp_callout, hz, arptimer, NULL);
934 }
935 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
Cache object: 32d04a33aeebb116f3159fd7cc74391e
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