Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / netinet / if_ether.c
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984263bc
MD
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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $
35 */
36
37/*
38 * Ethernet address resolution protocol.
39 * TODO:
40 * add "inuse/lock" bit (or ref. count) along with valid bit
41 */
42
43#include "opt_inet.h"
44#include "opt_bdg.h"
45
46#include <sys/param.h>
47#include <sys/kernel.h>
48#include <sys/queue.h>
49#include <sys/sysctl.h>
50#include <sys/systm.h>
51#include <sys/mbuf.h>
52#include <sys/malloc.h>
53#include <sys/socket.h>
54#include <sys/syslog.h>
55
56#include <net/if.h>
57#include <net/if_dl.h>
58#include <net/if_types.h>
59#include <net/route.h>
60#include <net/netisr.h>
61#include <net/if_llc.h>
62#ifdef BRIDGE
63#include <net/ethernet.h>
64#include <net/bridge.h>
65#endif
66
67#include <netinet/in.h>
68#include <netinet/in_var.h>
69#include <netinet/if_ether.h>
70
71#include <net/if_arc.h>
72#include <net/iso88025.h>
73
74#define SIN(s) ((struct sockaddr_in *)s)
75#define SDL(s) ((struct sockaddr_dl *)s)
76
77SYSCTL_DECL(_net_link_ether);
78SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
79
80/* timer values */
81static int arpt_prune = (5*60*1); /* walk list every 5 minutes */
82static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
83static int arpt_down = 20; /* once declared down, don't send for 20 sec */
84
85SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
86 &arpt_prune, 0, "");
87SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
88 &arpt_keep, 0, "");
89SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
90 &arpt_down, 0, "");
91
92#define rt_expire rt_rmx.rmx_expire
93
94struct llinfo_arp {
95 LIST_ENTRY(llinfo_arp) la_le;
96 struct rtentry *la_rt;
97 struct mbuf *la_hold; /* last packet until resolved/timeout */
98 u_short la_preempt; /* #times we QUERIED before entry expiration */
99 u_short la_asked; /* #times we QUERIED following expiration */
100#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */
101};
102
103static LIST_HEAD(, llinfo_arp) llinfo_arp;
104
105struct ifqueue arpintrq = {0, 0, 0, 50};
106static int arp_inuse, arp_allocated, arpinit_done;
107
108static int arp_maxtries = 5;
109static int useloopback = 1; /* use loopback interface for local traffic */
110static int arp_proxyall = 0;
111
112SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
113 &arp_maxtries, 0, "");
114SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
115 &useloopback, 0, "");
116SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
117 &arp_proxyall, 0, "");
118
119static void arp_rtrequest __P((int, struct rtentry *, struct rt_addrinfo *));
120static void arprequest __P((struct ifnet *,
121 struct in_addr *, struct in_addr *, u_char *));
122static void arpintr __P((void));
123static void arptfree __P((struct llinfo_arp *));
124static void arptimer __P((void *));
125static struct llinfo_arp
126 *arplookup __P((u_long, int, int));
127#ifdef INET
128static void in_arpinput __P((struct mbuf *));
129#endif
130
131u_char arcbroadcastaddr = 0;
132
133#define IF_BCASTADDR(ifp) \
134 ((ifp)->if_type == IFT_ARCNET ? \
135 &arcbroadcastaddr : etherbroadcastaddr)
136
137/*
138 * Timeout routine. Age arp_tab entries periodically.
139 */
140/* ARGSUSED */
141static void
142arptimer(ignored_arg)
143 void *ignored_arg;
144{
145 int s = splnet();
146 register struct llinfo_arp *la = LIST_FIRST(&llinfo_arp);
147 struct llinfo_arp *ola;
148
149 timeout(arptimer, (caddr_t)0, arpt_prune * hz);
150 while ((ola = la) != 0) {
151 register struct rtentry *rt = la->la_rt;
152 la = LIST_NEXT(la, la_le);
153 if (rt->rt_expire && rt->rt_expire <= time_second)
154 arptfree(ola); /* timer has expired, clear */
155 }
156 splx(s);
157}
158
159/*
160 * Parallel to llc_rtrequest.
161 */
162static void
163arp_rtrequest(req, rt, info)
164 int req;
165 register struct rtentry *rt;
166 struct rt_addrinfo *info;
167{
168 register struct sockaddr *gate = rt->rt_gateway;
169 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
170 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
171
172 if (!arpinit_done) {
173 arpinit_done = 1;
174 timeout(arptimer, (caddr_t)0, hz);
175 }
176 if (rt->rt_flags & RTF_GATEWAY)
177 return;
178 switch (req) {
179
180 case RTM_ADD:
181 /*
182 * XXX: If this is a manually added route to interface
183 * such as older version of routed or gated might provide,
184 * restore cloning bit.
185 */
186 if ((rt->rt_flags & RTF_HOST) == 0 &&
187 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
188 rt->rt_flags |= RTF_CLONING;
189 if (rt->rt_flags & RTF_CLONING) {
190 /*
191 * Case 1: This route should come from a route to iface.
192 */
193 rt_setgate(rt, rt_key(rt),
194 (struct sockaddr *)&null_sdl);
195 gate = rt->rt_gateway;
196 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
197 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
198 rt->rt_expire = time_second;
199 break;
200 }
201 /* Announce a new entry if requested. */
202 if (rt->rt_flags & RTF_ANNOUNCE)
203 arprequest(rt->rt_ifp,
204 &SIN(rt_key(rt))->sin_addr,
205 &SIN(rt_key(rt))->sin_addr,
206 (u_char *)LLADDR(SDL(gate)));
207 /*FALLTHROUGH*/
208 case RTM_RESOLVE:
209 if (gate->sa_family != AF_LINK ||
210 gate->sa_len < sizeof(null_sdl)) {
211 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
212 break;
213 }
214 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
215 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
216 if (la != 0)
217 break; /* This happens on a route change */
218 /*
219 * Case 2: This route may come from cloning, or a manual route
220 * add with a LL address.
221 */
222 R_Malloc(la, struct llinfo_arp *, sizeof(*la));
223 rt->rt_llinfo = (caddr_t)la;
224 if (la == 0) {
225 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
226 break;
227 }
228 arp_inuse++, arp_allocated++;
229 Bzero(la, sizeof(*la));
230 la->la_rt = rt;
231 rt->rt_flags |= RTF_LLINFO;
232 LIST_INSERT_HEAD(&llinfo_arp, la, la_le);
233
234#ifdef INET
235 /*
236 * This keeps the multicast addresses from showing up
237 * in `arp -a' listings as unresolved. It's not actually
238 * functional. Then the same for broadcast.
239 */
240 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))
241 && rt->rt_ifp->if_type != IFT_ARCNET) {
242 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
243 LLADDR(SDL(gate)));
244 SDL(gate)->sdl_alen = 6;
245 rt->rt_expire = 0;
246 }
247 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) {
248 memcpy(LLADDR(SDL(gate)), IF_BCASTADDR(rt->rt_ifp),
249 rt->rt_ifp->if_addrlen);
250 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen;
251 rt->rt_expire = 0;
252 }
253#endif
254
255 if (SIN(rt_key(rt))->sin_addr.s_addr ==
256 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
257 /*
258 * This test used to be
259 * if (loif.if_flags & IFF_UP)
260 * It allowed local traffic to be forced
261 * through the hardware by configuring the loopback down.
262 * However, it causes problems during network configuration
263 * for boards that can't receive packets they send.
264 * It is now necessary to clear "useloopback" and remove
265 * the route to force traffic out to the hardware.
266 */
267 rt->rt_expire = 0;
268 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)),
269 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen);
270 if (useloopback)
271 rt->rt_ifp = loif;
272
273 }
274 break;
275
276 case RTM_DELETE:
277 if (la == 0)
278 break;
279 arp_inuse--;
280 LIST_REMOVE(la, la_le);
281 rt->rt_llinfo = 0;
282 rt->rt_flags &= ~RTF_LLINFO;
283 if (la->la_hold)
284 m_freem(la->la_hold);
285 Free((caddr_t)la);
286 }
287}
288
289/*
290 * Broadcast an ARP request. Caller specifies:
291 * - arp header source ip address
292 * - arp header target ip address
293 * - arp header source ethernet address
294 */
295static void
296arprequest(ifp, sip, tip, enaddr)
297 register struct ifnet *ifp;
298 register struct in_addr *sip, *tip;
299 register u_char *enaddr;
300{
301 register struct mbuf *m;
302 register struct ether_header *eh;
303 register struct arc_header *arh;
304 register struct arphdr *ah;
305 struct sockaddr sa;
306 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP,
307 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 };
308 u_short ar_hrd;
309
310 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
311 return;
312 m->m_pkthdr.rcvif = (struct ifnet *)0;
313 switch (ifp->if_type) {
314 case IFT_ARCNET:
315 ar_hrd = htons(ARPHRD_ARCNET);
316
317 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
318 m->m_pkthdr.len = m->m_len;
319 MH_ALIGN(m, m->m_len);
320
321 arh = (struct arc_header *)sa.sa_data;
322 arh->arc_dhost = arcbroadcastaddr;
323 arh->arc_type = ARCTYPE_ARP;
324
325 ah = mtod(m, struct arphdr *);
326 break;
327
328 case IFT_ISO88025:
329 ar_hrd = htons(ARPHRD_IEEE802);
330
331 m->m_len = sizeof(llcx) +
332 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
333 m->m_pkthdr.len = m->m_len;
334 MH_ALIGN(m, m->m_len);
335
336 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx));
337 (void)memcpy(sa.sa_data, etherbroadcastaddr, 6);
338 (void)memcpy(sa.sa_data + 6, enaddr, 6);
339 sa.sa_data[6] |= TR_RII;
340 sa.sa_data[12] = TR_AC;
341 sa.sa_data[13] = TR_LLC_FRAME;
342
343 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx));
344 break;
345 case IFT_FDDI:
346 case IFT_ETHER:
347 /*
348 * This may not be correct for types not explicitly
349 * listed, but this is our best guess
350 */
351 default:
352 ar_hrd = htons(ARPHRD_ETHER);
353
354 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
355 m->m_pkthdr.len = m->m_len;
356 MH_ALIGN(m, m->m_len);
357
358 eh = (struct ether_header *)sa.sa_data;
359 /* if_output will not swap */
360 eh->ether_type = htons(ETHERTYPE_ARP);
361 (void)memcpy(eh->ether_dhost, etherbroadcastaddr,
362 sizeof(eh->ether_dhost));
363
364 ah = mtod(m, struct arphdr *);
365 break;
366 }
367
368 ah->ar_hrd = ar_hrd;
369 ah->ar_pro = htons(ETHERTYPE_IP);
370 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
371 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
372 ah->ar_op = htons(ARPOP_REQUEST);
373 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
374 memset(ar_tha(ah), 0, ah->ar_hln);
375 (void)memcpy(ar_spa(ah), sip, ah->ar_pln);
376 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln);
377
378 sa.sa_family = AF_UNSPEC;
379 sa.sa_len = sizeof(sa);
380 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
381}
382
383/*
384 * Resolve an IP address into an ethernet address. If success,
385 * desten is filled in. If there is no entry in arptab,
386 * set one up and broadcast a request for the IP address.
387 * Hold onto this mbuf and resend it once the address
388 * is finally resolved. A return value of 1 indicates
389 * that desten has been filled in and the packet should be sent
390 * normally; a 0 return indicates that the packet has been
391 * taken over here, either now or for later transmission.
392 */
393int
394arpresolve(ifp, rt, m, dst, desten, rt0)
395 register struct ifnet *ifp;
396 register struct rtentry *rt;
397 struct mbuf *m;
398 register struct sockaddr *dst;
399 register u_char *desten;
400 struct rtentry *rt0;
401{
402 struct llinfo_arp *la = 0;
403 struct sockaddr_dl *sdl;
404
405 if (m->m_flags & M_BCAST) { /* broadcast */
406 (void)memcpy(desten, IF_BCASTADDR(ifp), ifp->if_addrlen);
407 return (1);
408 }
409 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */
410 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
411 return(1);
412 }
413 if (rt)
414 la = (struct llinfo_arp *)rt->rt_llinfo;
415 if (la == 0) {
416 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0);
417 if (la)
418 rt = la->la_rt;
419 }
420 if (la == 0 || rt == 0) {
421 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n",
422 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "",
423 rt ? "rt" : "");
424 m_freem(m);
425 return (0);
426 }
427 sdl = SDL(rt->rt_gateway);
428 /*
429 * Check the address family and length is valid, the address
430 * is resolved; otherwise, try to resolve.
431 */
432 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) &&
433 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
434 /*
435 * If entry has an expiry time and it is approaching,
436 * see if we need to send an ARP request within this
437 * arpt_down interval.
438 */
439 if ((rt->rt_expire != 0) &&
440 (time_second + (arp_maxtries - la->la_preempt) * arpt_down
441 > rt->rt_expire)) {
442 arprequest(ifp,
443 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
444 &SIN(dst)->sin_addr,
445 IF_LLADDR(ifp));
446 la->la_preempt++;
447 }
448
449 bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
450 return 1;
451 }
452 /*
453 * If ARP is disabled on this interface, stop.
454 * XXX
455 * Probably should not allocate empty llinfo struct if we are
456 * not going to be sending out an arp request.
457 */
458 if (ifp->if_flags & IFF_NOARP) {
459 m_freem(m);
460 return (0);
461 }
462 /*
463 * There is an arptab entry, but no ethernet address
464 * response yet. Replace the held mbuf with this
465 * latest one.
466 */
467 if (la->la_hold)
468 m_freem(la->la_hold);
469 la->la_hold = m;
470 if (rt->rt_expire) {
471 rt->rt_flags &= ~RTF_REJECT;
472 if (la->la_asked == 0 || rt->rt_expire != time_second) {
473 rt->rt_expire = time_second;
474 if (la->la_asked++ < arp_maxtries) {
475 arprequest(ifp,
476 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
477 &SIN(dst)->sin_addr,
478 IF_LLADDR(ifp));
479 } else {
480 rt->rt_flags |= RTF_REJECT;
481 rt->rt_expire += arpt_down;
482 la->la_preempt = la->la_asked = 0;
483 }
484
485 }
486 }
487 return (0);
488}
489
490/*
491 * Common length and type checks are done here,
492 * then the protocol-specific routine is called.
493 */
494static void
495arpintr()
496{
497 register struct mbuf *m;
498 register struct arphdr *ar;
499 int s;
500
501 while (arpintrq.ifq_head) {
502 s = splimp();
503 IF_DEQUEUE(&arpintrq, m);
504 splx(s);
505 if (m == 0 || (m->m_flags & M_PKTHDR) == 0)
506 panic("arpintr");
507
508 if (m->m_len < sizeof(struct arphdr) &&
509 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
510 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
511 continue;
512 }
513 ar = mtod(m, struct arphdr *);
514
515 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER
516 && ntohs(ar->ar_hrd) != ARPHRD_IEEE802
517 && ntohs(ar->ar_hrd) != ARPHRD_ARCNET) {
518 log(LOG_ERR,
519 "arp: unknown hardware address format (0x%2D)\n",
520 (unsigned char *)&ar->ar_hrd, "");
521 m_freem(m);
522 continue;
523 }
524
525 if (m->m_pkthdr.len < arphdr_len(ar) &&
526 (m = m_pullup(m, arphdr_len(ar))) == NULL) {
527 log(LOG_ERR, "arp: runt packet\n");
528 m_freem(m);
529 continue;
530 }
531
532 switch (ntohs(ar->ar_pro)) {
533#ifdef INET
534 case ETHERTYPE_IP:
535 in_arpinput(m);
536 continue;
537#endif
538 }
539 m_freem(m);
540 }
541}
542
543#ifdef INET
544/*
545 * ARP for Internet protocols on 10 Mb/s Ethernet.
546 * Algorithm is that given in RFC 826.
547 * In addition, a sanity check is performed on the sender
548 * protocol address, to catch impersonators.
549 * We no longer handle negotiations for use of trailer protocol:
550 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
551 * along with IP replies if we wanted trailers sent to us,
552 * and also sent them in response to IP replies.
553 * This allowed either end to announce the desire to receive
554 * trailer packets.
555 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
556 * but formerly didn't normally send requests.
557 */
558static int log_arp_wrong_iface = 1;
559
560SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
561 &log_arp_wrong_iface, 0,
562 "log arp packets arriving on the wrong interface");
563
564static void
565in_arpinput(m)
566 struct mbuf *m;
567{
568 register struct arphdr *ah;
569 register struct ifnet *ifp = m->m_pkthdr.rcvif;
570 struct ether_header *eh;
571 struct arc_header *arh;
572 struct iso88025_header *th = (struct iso88025_header *)0;
573 struct iso88025_sockaddr_dl_data *trld;
574 register struct llinfo_arp *la = 0;
575 register struct rtentry *rt;
576 struct ifaddr *ifa;
577 struct in_ifaddr *ia;
578 struct sockaddr_dl *sdl;
579 struct sockaddr sa;
580 struct in_addr isaddr, itaddr, myaddr;
581 int op, rif_len;
582 int req_len;
583
584 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
585 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
586 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
587 return;
588 }
589
590 ah = mtod(m, struct arphdr *);
591 op = ntohs(ah->ar_op);
592 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
593 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
594#ifdef BRIDGE
595#define BRIDGE_TEST (do_bridge)
596#else
597#define BRIDGE_TEST (0) /* cc will optimise the test away */
598#endif
599 /*
600 * For a bridge, we want to check the address irrespective
601 * of the receive interface. (This will change slightly
602 * when we have clusters of interfaces).
603 */
604 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash)
605 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) &&
606 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr)
607 goto match;
608 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
609 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) &&
610 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)
611 goto match;
612 /*
613 * No match, use the first inet address on the receive interface
614 * as a dummy address for the rest of the function.
615 */
616 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
617 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
618 ia = ifatoia(ifa);
619 goto match;
620 }
621 /*
622 * If bridging, fall back to using any inet address.
623 * This is probably incorrect, the right way being try to match
624 * addresses for interfaces in the same cluster, so if we
625 * get here we should always drop the packet.
626 */
627 if (!BRIDGE_TEST ||
628 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) {
629 m_freem(m);
630 return;
631 }
632match:
633 myaddr = ia->ia_addr.sin_addr;
634 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) {
635 m_freem(m); /* it's from me, ignore it. */
636 return;
637 }
638 if (!bcmp(ar_sha(ah), IF_BCASTADDR(ifp), ifp->if_addrlen)) {
639 log(LOG_ERR,
640 "arp: link address is broadcast for IP address %s!\n",
641 inet_ntoa(isaddr));
642 m_freem(m);
643 return;
644 }
645 if (isaddr.s_addr == myaddr.s_addr) {
646 log(LOG_ERR,
647 "arp: %*D is using my IP address %s!\n",
648 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
649 inet_ntoa(isaddr));
650 itaddr = myaddr;
651 goto reply;
652 }
653 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);
654 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
655 /* the following is not an error when doing bridging */
656 if (!BRIDGE_TEST && rt->rt_ifp != ifp) {
657 if (log_arp_wrong_iface)
658 log(LOG_ERR, "arp: %s is on %s%d but got reply from %*D on %s%d\n",
659 inet_ntoa(isaddr),
660 rt->rt_ifp->if_name, rt->rt_ifp->if_unit,
661 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
662 ifp->if_name, ifp->if_unit);
663 goto reply;
664 }
665 if (sdl->sdl_alen &&
666 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) {
667 if (rt->rt_expire)
668 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s%d\n",
669 inet_ntoa(isaddr),
670 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":",
671 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
672 ifp->if_name, ifp->if_unit);
673 else {
674 log(LOG_ERR,
675 "arp: %*D attempts to modify permanent entry for %s on %s%d\n",
676 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
677 inet_ntoa(isaddr), ifp->if_name, ifp->if_unit);
678 goto reply;
679 }
680 }
681 /*
682 * sanity check for the address length.
683 * XXX this does not work for protocols with variable address
684 * length. -is
685 */
686 if (sdl->sdl_alen &&
687 sdl->sdl_alen != ah->ar_hln) {
688 log(LOG_WARNING,
689 "arp from %*D: new addr len %d, was %d",
690 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
691 ah->ar_hln, sdl->sdl_alen);
692 }
693 if (ifp->if_addrlen != ah->ar_hln) {
694 log(LOG_WARNING,
695 "arp from %*D: addr len: new %d, i/f %d (ignored)",
696 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
697 ah->ar_hln, ifp->if_addrlen);
698 goto reply;
699 }
700 (void)memcpy(LLADDR(sdl), ar_sha(ah),
701 sdl->sdl_alen = ah->ar_hln);
702 /*
703 * If we receive an arp from a token-ring station over
704 * a token-ring nic then try to save the source
705 * routing info.
706 */
707 if (ifp->if_type == IFT_ISO88025) {
708 th = (struct iso88025_header *)m->m_pkthdr.header;
709 trld = SDL_ISO88025(sdl);
710 rif_len = TR_RCF_RIFLEN(th->rcf);
711 if ((th->iso88025_shost[0] & TR_RII) &&
712 (rif_len > 2)) {
713 trld->trld_rcf = th->rcf;
714 trld->trld_rcf ^= htons(TR_RCF_DIR);
715 memcpy(trld->trld_route, th->rd, rif_len - 2);
716 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK);
717 /*
718 * Set up source routing information for
719 * reply packet (XXX)
720 */
721 m->m_data -= rif_len;
722 m->m_len += rif_len;
723 m->m_pkthdr.len += rif_len;
724 } else {
725 th->iso88025_shost[0] &= ~TR_RII;
726 trld->trld_rcf = 0;
727 }
728 m->m_data -= 8;
729 m->m_len += 8;
730 m->m_pkthdr.len += 8;
731 th->rcf = trld->trld_rcf;
732 }
733 if (rt->rt_expire)
734 rt->rt_expire = time_second + arpt_keep;
735 rt->rt_flags &= ~RTF_REJECT;
736 la->la_preempt = la->la_asked = 0;
737 if (la->la_hold) {
738 (*ifp->if_output)(ifp, la->la_hold,
739 rt_key(rt), rt);
740 la->la_hold = 0;
741 }
742 }
743reply:
744 if (op != ARPOP_REQUEST) {
745 m_freem(m);
746 return;
747 }
748 if (itaddr.s_addr == myaddr.s_addr) {
749 /* I am the target */
750 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
751 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln);
752 } else {
753 la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
754 if (la == NULL) {
755 struct sockaddr_in sin;
756
757 if (!arp_proxyall) {
758 m_freem(m);
759 return;
760 }
761
762 bzero(&sin, sizeof sin);
763 sin.sin_family = AF_INET;
764 sin.sin_len = sizeof sin;
765 sin.sin_addr = itaddr;
766
767 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
768 if (!rt) {
769 m_freem(m);
770 return;
771 }
772 /*
773 * Don't send proxies for nodes on the same interface
774 * as this one came out of, or we'll get into a fight
775 * over who claims what Ether address.
776 */
777 if (rt->rt_ifp == ifp) {
778 rtfree(rt);
779 m_freem(m);
780 return;
781 }
782 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
783 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln);
784 rtfree(rt);
785#ifdef DEBUG_PROXY
786 printf("arp: proxying for %s\n",
787 inet_ntoa(itaddr));
788#endif
789 } else {
790 rt = la->la_rt;
791 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
792 sdl = SDL(rt->rt_gateway);
793 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln);
794 }
795 }
796
797 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
798 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
799 ah->ar_op = htons(ARPOP_REPLY);
800 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
801 switch (ifp->if_type) {
802 case IFT_ARCNET:
803 arh = (struct arc_header *)sa.sa_data;
804 arh->arc_dhost = *ar_tha(ah);
805 arh->arc_type = ARCTYPE_ARP;
806 break;
807
808 case IFT_ISO88025:
809 /* Re-arrange the source/dest address */
810 memcpy(th->iso88025_dhost, th->iso88025_shost,
811 sizeof(th->iso88025_dhost));
812 memcpy(th->iso88025_shost, IF_LLADDR(ifp),
813 sizeof(th->iso88025_shost));
814 /* Set the source routing bit if neccesary */
815 if (th->iso88025_dhost[0] & TR_RII) {
816 th->iso88025_dhost[0] &= ~TR_RII;
817 if (TR_RCF_RIFLEN(th->rcf) > 2)
818 th->iso88025_shost[0] |= TR_RII;
819 }
820 /* Copy the addresses, ac and fc into sa_data */
821 memcpy(sa.sa_data, th->iso88025_dhost,
822 sizeof(th->iso88025_dhost) * 2);
823 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC;
824 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME;
825 break;
826 case IFT_ETHER:
827 case IFT_FDDI:
828 /*
829 * May not be correct for types not explictly
830 * listed, but it is our best guess.
831 */
832 default:
833 eh = (struct ether_header *)sa.sa_data;
834 (void)memcpy(eh->ether_dhost, ar_tha(ah),
835 sizeof(eh->ether_dhost));
836 eh->ether_type = htons(ETHERTYPE_ARP);
837 break;
838 }
839 sa.sa_family = AF_UNSPEC;
840 sa.sa_len = sizeof(sa);
841 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
842 return;
843}
844#endif
845
846/*
847 * Free an arp entry.
848 */
849static void
850arptfree(la)
851 register struct llinfo_arp *la;
852{
853 register struct rtentry *rt = la->la_rt;
854 register struct sockaddr_dl *sdl;
855 if (rt == 0)
856 panic("arptfree");
857 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
858 sdl->sdl_family == AF_LINK) {
859 sdl->sdl_alen = 0;
860 la->la_preempt = la->la_asked = 0;
861 rt->rt_flags &= ~RTF_REJECT;
862 return;
863 }
864 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
865 0, (struct rtentry **)0);
866}
867/*
868 * Lookup or enter a new address in arptab.
869 */
870static struct llinfo_arp *
871arplookup(addr, create, proxy)
872 u_long addr;
873 int create, proxy;
874{
875 register struct rtentry *rt;
876 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET };
877 const char *why = 0;
878
879 sin.sin_addr.s_addr = addr;
880 sin.sin_other = proxy ? SIN_PROXY : 0;
881 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL);
882 if (rt == 0)
883 return (0);
884 rt->rt_refcnt--;
885
886 if (rt->rt_flags & RTF_GATEWAY)
887 why = "host is not on local network";
888 else if ((rt->rt_flags & RTF_LLINFO) == 0)
889 why = "could not allocate llinfo";
890 else if (rt->rt_gateway->sa_family != AF_LINK)
891 why = "gateway route is not ours";
892
893 if (why && create) {
894 log(LOG_DEBUG, "arplookup %s failed: %s\n",
895 inet_ntoa(sin.sin_addr), why);
896 return 0;
897 } else if (why) {
898 return 0;
899 }
900 return ((struct llinfo_arp *)rt->rt_llinfo);
901}
902
903void
904arp_ifinit(ifp, ifa)
905 struct ifnet *ifp;
906 struct ifaddr *ifa;
907{
908 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
909 arprequest(ifp, &IA_SIN(ifa)->sin_addr,
910 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
911 ifa->ifa_rtrequest = arp_rtrequest;
912 ifa->ifa_flags |= RTF_CLONING;
913}
914
915static void
916arp_init(void)
917{
918 LIST_INIT(&llinfo_arp);
919 register_netisr(NETISR_ARP, arpintr);
920}
921
922SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);