1 /*
2 * Copyright (c) 2004, 2005 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Jeffrey M. Hsu.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of The DragonFly Project nor the names of its
16 * contributors may be used to endorse or promote products derived
17 * from this software without specific, prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
23 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
25 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
27 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
28 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
29 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * Copyright (c) 1982, 1986, 1988, 1993
35 * The Regents of the University of California. All rights reserved.
36 *
37 * Redistribution and use in source and binary forms, with or without
38 * modification, are permitted provided that the following conditions
39 * are met:
40 * 1. Redistributions of source code must retain the above copyright
41 * notice, this list of conditions and the following disclaimer.
42 * 2. Redistributions in binary form must reproduce the above copyright
43 * notice, this list of conditions and the following disclaimer in the
44 * documentation and/or other materials provided with the distribution.
45 * 3. All advertising materials mentioning features or use of this software
46 * must display the following acknowledgement:
47 * This product includes software developed by the University of
48 * California, Berkeley and its contributors.
49 * 4. Neither the name of the University nor the names of its contributors
50 * may be used to endorse or promote products derived from this software
51 * without specific prior written permission.
52 *
53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63 * SUCH DAMAGE.
64 *
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 $
68 */
69
70 /*
71 * Ethernet address resolution protocol.
72 * TODO:
73 * add "inuse/lock" bit (or ref. count) along with valid bit
74 */
75
76 #include "opt_inet.h"
77 #include "opt_carp.h"
78
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>
84 #include <sys/mbuf.h>
85 #include <sys/malloc.h>
86 #include <sys/socket.h>
87 #include <sys/syslog.h>
88 #include <sys/lock.h>
89
90 #include <net/if.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>
96
97 #include <netinet/in.h>
98 #include <netinet/in_var.h>
99 #include <netinet/if_ether.h>
100
101 #include <sys/thread2.h>
102 #include <sys/msgport2.h>
103 #include <net/netmsg2.h>
104 #include <sys/mplock2.h>
105
106 #ifdef CARP
107 #include <netinet/ip_carp.h>
108 #endif
109
110 #define SIN(s) ((struct sockaddr_in *)s)
111 #define SDL(s) ((struct sockaddr_dl *)s)
112
113 SYSCTL_DECL(_net_link_ether);
114 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
115
116 /* timer values */
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 */
120
121 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
122 &arpt_prune, 0, "");
123 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
124 &arpt_keep, 0, "");
125 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
126 &arpt_down, 0, "");
127
128 #define rt_expire rt_rmx.rmx_expire
129
130 struct llinfo_arp {
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 */
137 };
138
139 static LIST_HEAD(, llinfo_arp) llinfo_arp_list[MAXCPU];
140
141 static int arp_maxtries = 5;
142 static int useloopback = 1; /* use loopback interface for local traffic */
143 static int arp_proxyall = 0;
144
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");
151
152 static int arp_mpsafe = 1;
153 TUNABLE_INT("net.link.ether.inet.arp_mpsafe", &arp_mpsafe);
154
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);
165 #ifdef INET
166 static void in_arpinput(struct mbuf *);
167 #endif
168
169 static struct callout arptimer_ch[MAXCPU];
170
171 /*
172 * Timeout routine. Age arp_tab entries periodically.
173 */
174 /* ARGSUSED */
175 static void
176 arptimer(void *ignored_arg)
177 {
178 struct llinfo_arp *la, *nla;
179
180 crit_enter();
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)
183 arptfree(la);
184 }
185 callout_reset(&arptimer_ch[mycpuid], arpt_prune * hz, arptimer, NULL);
186 crit_exit();
187 }
188
189 /*
190 * Parallel to llc_rtrequest.
191 */
192 static void
193 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info)
194 {
195 struct sockaddr *gate = rt->rt_gateway;
196 struct llinfo_arp *la = rt->rt_llinfo;
197
198 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK };
199 static boolean_t arpinit_done[MAXCPU];
200
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);
205 }
206 if (rt->rt_flags & RTF_GATEWAY)
207 return;
208
209 switch (req) {
210 case RTM_ADD:
211 /*
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.
215 */
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) {
220 /*
221 * Case 1: This route should come from a route to iface.
222 */
223 rt_setgate(rt, rt_key(rt),
224 (struct sockaddr *)&null_sdl,
225 RTL_DONTREPORT);
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;
230 break;
231 }
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,
237 LLADDR(SDL(gate)));
238 }
239 /*FALLTHROUGH*/
240 case RTM_RESOLVE:
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");
244 break;
245 }
246 SDL(gate)->sdl_type = rt->rt_ifp->if_type;
247 SDL(gate)->sdl_index = rt->rt_ifp->if_index;
248 if (la != NULL)
249 break; /* This happens on a route change */
250 /*
251 * Case 2: This route may come from cloning, or a manual route
252 * add with a LL address.
253 */
254 R_Malloc(la, struct llinfo_arp *, sizeof *la);
255 rt->rt_llinfo = la;
256 if (la == NULL) {
257 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
258 break;
259 }
260 bzero(la, sizeof *la);
261 la->la_rt = rt;
262 rt->rt_flags |= RTF_LLINFO;
263 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le);
264
265 #ifdef INET
266 /*
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.
270 */
271 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) {
272 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
273 LLADDR(SDL(gate)));
274 SDL(gate)->sdl_alen = 6;
275 rt->rt_expire = 0;
276 }
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;
281 rt->rt_expire = 0;
282 }
283 #endif
284
285 if (SIN(rt_key(rt))->sin_addr.s_addr ==
286 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
287 /*
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
297 * the hardware.
298 */
299 rt->rt_expire = 0;
300 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)),
301 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen);
302 if (useloopback)
303 rt->rt_ifp = loif;
304 }
305 break;
306
307 case RTM_DELETE:
308 if (la == NULL)
309 break;
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);
315 Free(la);
316 break;
317 }
318 }
319
320 static struct mbuf *
321 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip,
322 const struct in_addr *tip, const u_char *enaddr)
323 {
324 struct mbuf *m;
325 struct arphdr *ah;
326 u_short ar_hrd;
327
328 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL)
329 return NULL;
330 m->m_pkthdr.rcvif = NULL;
331
332 switch (ifp->if_type) {
333 case IFT_ETHER:
334 /*
335 * This may not be correct for types not explicitly
336 * listed, but this is our best guess
337 */
338 default:
339 ar_hrd = htons(ARPHRD_ETHER);
340
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);
344
345 ah = mtod(m, struct arphdr *);
346 break;
347 }
348
349 ah->ar_hrd = ar_hrd;
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);
358
359 return m;
360 }
361
362 static void
363 arpreq_send(struct ifnet *ifp, struct mbuf *m)
364 {
365 struct sockaddr sa;
366 struct ether_header *eh;
367
368 switch (ifp->if_type) {
369 case IFT_ETHER:
370 /*
371 * This may not be correct for types not explicitly
372 * listed, but this is our best guess
373 */
374 default:
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);
379 break;
380 }
381
382 sa.sa_family = AF_UNSPEC;
383 sa.sa_len = sizeof(sa);
384 ifp->if_output(ifp, m, &sa, NULL);
385 }
386
387 static void
388 arpreq_send_handler(struct netmsg *nmsg)
389 {
390 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet;
391 struct ifnet *ifp = nmsg->nm_lmsg.u.ms_resultp;
392
393 arpreq_send(ifp, m);
394 /* nmsg was embedded in the mbuf, do not reply! */
395 }
396
397 /*
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
402 *
403 * NOTE: Caller MUST NOT hold ifp's serializer
404 */
405 static void
406 arprequest(struct ifnet *ifp, const struct in_addr *sip,
407 const struct in_addr *tip, const u_char *enaddr)
408 {
409 struct mbuf *m;
410
411 m = arpreq_alloc(ifp, sip, tip, enaddr);
412 if (m == NULL)
413 return;
414 arpreq_send(ifp, m);
415 }
416
417 /*
418 * Same as arprequest(), except:
419 * - Caller is allowed to hold ifp's serializer
420 * - Network output is done in TDF_NETWORK kernel thread
421 */
422 static void
423 arprequest_async(struct ifnet *ifp, const struct in_addr *sip,
424 const struct in_addr *tip, const u_char *enaddr)
425 {
426 struct mbuf *m;
427 struct netmsg_packet *pmsg;
428
429 m = arpreq_alloc(ifp, sip, tip, enaddr);
430 if (m == NULL)
431 return;
432
433 pmsg = &m->m_hdr.mh_netmsg;
434 netmsg_init(&pmsg->nm_netmsg, NULL, &netisr_apanic_rport,
435 0, arpreq_send_handler);
436 pmsg->nm_packet = m;
437 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = ifp;
438
439 lwkt_sendmsg(cpu_portfn(mycpuid), &pmsg->nm_netmsg.nm_lmsg);
440 }
441
442 /*
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.
451 */
452 int
453 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
454 struct sockaddr *dst, u_char *desten)
455 {
456 struct rtentry *rt;
457 struct llinfo_arp *la = NULL;
458 struct sockaddr_dl *sdl;
459
460 if (m->m_flags & M_BCAST) { /* broadcast */
461 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen);
462 return (1);
463 }
464 if (m->m_flags & M_MCAST) {/* multicast */
465 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
466 return (1);
467 }
468 if (rt0 != NULL) {
469 if (rt_llroute(dst, rt0, &rt) != 0) {
470 m_freem(m);
471 return 0;
472 }
473 la = rt->rt_llinfo;
474 }
475 if (la == NULL) {
476 la = arplookup(SIN(dst)->sin_addr.s_addr,
477 TRUE, RTL_REPORTMSG, FALSE);
478 if (la != NULL)
479 rt = la->la_rt;
480 }
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" : " ",
484 rt ? "rt" : "");
485 m_freem(m);
486 return (0);
487 }
488 sdl = SDL(rt->rt_gateway);
489 /*
490 * Check the address family and length is valid, the address
491 * is resolved; otherwise, try to resolve.
492 */
493 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) &&
494 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
495 /*
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.
499 */
500 if ((rt->rt_expire != 0) &&
501 (time_second + la->la_preempt > rt->rt_expire)) {
502 arprequest(ifp,
503 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
504 &SIN(dst)->sin_addr,
505 IF_LLADDR(ifp));
506 la->la_preempt--;
507 }
508
509 bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
510 return 1;
511 }
512 /*
513 * If ARP is disabled or static on this interface, stop.
514 * XXX
515 * Probably should not allocate empty llinfo struct if we are
516 * not going to be sending out an arp request.
517 */
518 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) {
519 m_freem(m);
520 return (0);
521 }
522 /*
523 * There is an arptab entry, but no ethernet address
524 * response yet. Replace the held mbuf with this
525 * latest one.
526 */
527 if (la->la_hold != NULL)
528 m_freem(la->la_hold);
529 la->la_hold = m;
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) {
536 arprequest(ifp,
537 &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
538 &SIN(dst)->sin_addr,
539 IF_LLADDR(ifp));
540 } else {
541 rt->rt_flags |= RTF_REJECT;
542 rt->rt_expire += arpt_down;
543 la->la_asked = 0;
544 la->la_preempt = arp_maxtries;
545 }
546 }
547 }
548 return (0);
549 }
550
551 /*
552 * Common length and type checks are done here,
553 * then the protocol-specific routine is called.
554 */
555 static void
556 arpintr(struct netmsg *msg)
557 {
558 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet;
559 struct arphdr *ar;
560 u_short ar_hrd;
561
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");
565 return;
566 }
567 ar = mtod(m, struct arphdr *);
568
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, "");
573 m_freem(m);
574 return;
575 }
576
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");
580 return;
581 }
582 ar = mtod(m, struct arphdr *);
583 }
584
585 switch (ntohs(ar->ar_pro)) {
586 #ifdef INET
587 case ETHERTYPE_IP:
588 in_arpinput(m);
589 return;
590 #endif
591 }
592 m_freem(m);
593 /* msg was embedded in the mbuf, do not reply! */
594 }
595
596 #ifdef INET
597 /*
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
607 * trailer packets.
608 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
609 * but formerly didn't normally send requests.
610 */
611
612 static int log_arp_wrong_iface = 1;
613 static int log_arp_movements = 1;
614 static int log_arp_permanent_modify = 1;
615
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");
626
627
628 static void
629 arp_hold_output(struct netmsg *nmsg)
630 {
631 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet;
632 struct rtentry *rt;
633 struct ifnet *ifp;
634
635 rt = nmsg->nm_lmsg.u.ms_resultp;
636 ifp = m->m_pkthdr.rcvif;
637 m->m_pkthdr.rcvif = NULL;
638
639 ifp->if_output(ifp, m, rt_key(rt), rt);
640
641 /* Drop the reference count bumped by the sender */
642 RTFREE(rt);
643
644 /* nmsg was embedded in the mbuf, do not reply! */
645 }
646
647 static void
648 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create,
649 boolean_t generate_report, boolean_t dologging)
650 {
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;
655 struct rtentry *rt;
656
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 };
660
661 /* the following is not an error when doing bridging */
662 if (rt->rt_ifp != ifp) {
663 if (dologging && log_arp_wrong_iface) {
664 log(LOG_ERR,
665 "arp: %s is on %s "
666 "but got reply from %*D on %s\n",
667 inet_ntoa(isaddr),
668 rt->rt_ifp->if_xname,
669 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
670 ifp->if_xname);
671 }
672 return;
673 }
674 if (sdl->sdl_alen &&
675 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) {
676 if (rt->rt_expire != 0) {
677 if (dologging && log_arp_movements) {
678 log(LOG_INFO,
679 "arp: %s moved from %*D to %*D on %s\n",
680 inet_ntoa(isaddr),
681 ifp->if_addrlen, (u_char *)LLADDR(sdl),
682 ":", ifp->if_addrlen,
683 (u_char *)ar_sha(ah), ":",
684 ifp->if_xname);
685 }
686 } else {
687 if (dologging && log_arp_permanent_modify) {
688 log(LOG_ERR,
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);
693 }
694 return;
695 }
696 }
697 /*
698 * sanity check for the address length.
699 * XXX this does not work for protocols with variable address
700 * length. -is
701 */
702 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) {
703 log(LOG_WARNING,
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);
707 }
708 if (ifp->if_addrlen != ah->ar_hln) {
709 if (dologging) {
710 log(LOG_WARNING,
711 "arp from %*D: addr len: new %d, i/f %d "
712 "(ignored)",
713 ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
714 ah->ar_hln, ifp->if_addrlen);
715 }
716 return;
717 }
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;
722 la->la_asked = 0;
723 la->la_preempt = arp_maxtries;
724
725 /*
726 * This particular cpu might have been holding an mbuf
727 * pending ARP resolution. If so, transmit the mbuf now.
728 */
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;
733
734 la->la_hold = NULL;
735 la->la_msgport = NULL;
736
737 m_adj(m, sizeof(struct ether_header));
738
739 /*
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.
744 */
745 rt->rt_refcnt++;
746
747 pmsg = &m->m_hdr.mh_netmsg;
748 netmsg_init(&pmsg->nm_netmsg, NULL,
749 &netisr_apanic_rport,
750 MSGF_MPSAFE | MSGF_PRIORITY,
751 arp_hold_output);
752 pmsg->nm_packet = m;
753
754 /* Record necessary information */
755 m->m_pkthdr.rcvif = ifp;
756 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = rt;
757
758 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg);
759 }
760 }
761 }
762
763 #ifdef SMP
764
765 struct netmsg_arp_update {
766 struct netmsg netmsg;
767 struct mbuf *m;
768 in_addr_t saddr;
769 boolean_t create;
770 };
771
772 static void arp_update_msghandler(struct netmsg *);
773
774 #endif
775
776 /*
777 * Called from arpintr() - this routine is run from a single cpu.
778 */
779 static void
780 in_arpinput(struct mbuf *m)
781 {
782 struct arphdr *ah;
783 struct ifnet *ifp = m->m_pkthdr.rcvif;
784 struct ether_header *eh;
785 struct rtentry *rt;
786 struct ifaddr_container *ifac;
787 struct in_ifaddr_container *iac;
788 struct in_ifaddr *ia = NULL;
789 struct sockaddr sa;
790 struct in_addr isaddr, itaddr, myaddr;
791 #ifdef SMP
792 struct netmsg_arp_update msg;
793 #endif
794 uint8_t *enaddr = NULL;
795 int op;
796 int req_len;
797
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");
801 return;
802 }
803
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);
808
809 myaddr.s_addr = INADDR_ANY;
810 #ifdef CARP
811 if (ifp->if_carp != NULL) {
812 get_mplock();
813 if (ifp->if_carp != NULL &&
814 carp_iamatch(ifp->if_carp, &itaddr, &isaddr, &enaddr)) {
815 rel_mplock();
816 myaddr = itaddr;
817 goto match;
818 }
819 rel_mplock();
820 }
821 #endif
822
823 /*
824 * Check both target and sender IP addresses:
825 *
826 * If we receive the packet on the interface owning the address,
827 * then accept the address.
828 *
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).
832 */
833 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) {
834 ia = iac->ia;
835
836 /* Skip all ia's which don't match */
837 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
838 continue;
839 #ifdef CARP
840 if (ia->ia_ifp->if_type == IFT_CARP)
841 continue;
842 #endif
843 if (ia->ia_ifp == ifp)
844 goto match;
845
846 if (ifp->if_bridge && ia->ia_ifp &&
847 ifp->if_bridge == ia->ia_ifp->if_bridge)
848 goto match;
849 }
850 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) {
851 ia = iac->ia;
852
853 /* Skip all ia's which don't match */
854 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr)
855 continue;
856 #ifdef CARP
857 if (ia->ia_ifp->if_type == IFT_CARP)
858 continue;
859 #endif
860 if (ia->ia_ifp == ifp)
861 goto match;
862
863 if (ifp->if_bridge && ia->ia_ifp &&
864 ifp->if_bridge == ia->ia_ifp->if_bridge)
865 goto match;
866 }
867 /*
868 * No match, use the first inet address on the receive interface
869 * as a dummy address for the rest of the function.
870 */
871 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) {
872 struct ifaddr *ifa = ifac->ifa;
873
874 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
875 ia = ifatoia(ifa);
876 goto match;
877 }
878 }
879 /*
880 * If we got here, we didn't find any suitable interface,
881 * so drop the packet.
882 */
883 m_freem(m);
884 return;
885
886 match:
887 if (!enaddr)
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. */
893 return;
894 }
895 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
896 log(LOG_ERR,
897 "arp: link address is broadcast for IP address %s!\n",
898 inet_ntoa(isaddr));
899 m_freem(m);
900 return;
901 }
902 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) {
903 log(LOG_ERR,
904 "arp: %*D is using my IP address %s!\n",
905 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
906 inet_ntoa(isaddr));
907 itaddr = myaddr;
908 goto reply;
909 }
910 if (ifp->if_flags & IFF_STATICARP)
911 goto reply;
912 #ifdef SMP
913 netmsg_init(&msg.netmsg, NULL, &curthread->td_msgport,
914 0, arp_update_msghandler);
915 msg.m = m;
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);
919 #else
920 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr),
921 RTL_REPORTMSG, TRUE);
922 #endif
923 reply:
924 if (op != ARPOP_REQUEST) {
925 m_freem(m);
926 return;
927 }
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);
932 } else {
933 struct llinfo_arp *la;
934
935 la = arplookup(itaddr.s_addr, FALSE, RTL_DONTREPORT, SIN_PROXY);
936 if (la == NULL) {
937 struct sockaddr_in sin;
938
939 if (!arp_proxyall) {
940 m_freem(m);
941 return;
942 }
943
944 bzero(&sin, sizeof sin);
945 sin.sin_family = AF_INET;
946 sin.sin_len = sizeof sin;
947 sin.sin_addr = itaddr;
948
949 rt = rtpurelookup((struct sockaddr *)&sin);
950 if (rt == NULL) {
951 m_freem(m);
952 return;
953 }
954 --rt->rt_refcnt;
955 /*
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.
959 */
960 if (rt->rt_ifp == ifp) {
961 m_freem(m);
962 return;
963 }
964 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
965 memcpy(ar_sha(ah), enaddr, ah->ar_hln);
966 #ifdef DEBUG_PROXY
967 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr));
968 #endif
969 } else {
970 struct sockaddr_dl *sdl;
971
972 rt = la->la_rt;
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);
976 }
977 }
978
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) {
984 case IFT_ETHER:
985 /*
986 * May not be correct for types not explictly
987 * listed, but it is our best guess.
988 */
989 default:
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);
993 break;
994 }
995 sa.sa_family = AF_UNSPEC;
996 sa.sa_len = sizeof sa;
997 ifp->if_output(ifp, m, &sa, NULL);
998 }
999
1000 #ifdef SMP
1001
1002 static void
1003 arp_update_msghandler(struct netmsg *netmsg)
1004 {
1005 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg;
1006 int nextcpu;
1007
1008 /*
1009 * This message handler will be called on all of the CPUs,
1010 * however, we only need to generate rtmsg on CPU0.
1011 */
1012 arp_update_oncpu(msg->m, msg->saddr, msg->create,
1013 mycpuid == 0 ? RTL_REPORTMSG : RTL_DONTREPORT,
1014 mycpuid == 0);
1015
1016 nextcpu = mycpuid + 1;
1017 if (nextcpu < ncpus)
1018 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg);
1019 else
1020 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0);
1021 }
1022
1023 #endif /* SMP */
1024
1025 #endif /* INET */
1026
1027 /*
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.
1031 *
1032 * Note that static entries are created when route add ... -interface is used
1033 * to create an interface route to a (direct) destination.
1034 */
1035 static void
1036 arptfree(struct llinfo_arp *la)
1037 {
1038 struct rtentry *rt = la->la_rt;
1039 struct sockaddr_dl *sdl;
1040
1041 if (rt == NULL)
1042 panic("arptfree");
1043 sdl = SDL(rt->rt_gateway);
1044 if (sdl != NULL &&
1045 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) ||
1046 (rt->rt_flags & RTF_STATIC))) {
1047 sdl->sdl_alen = 0;
1048 la->la_preempt = la->la_asked = 0;
1049 rt->rt_flags &= ~RTF_REJECT;
1050 return;
1051 }
1052 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL);
1053 }
1054
1055 /*
1056 * Lookup or enter a new address in arptab.
1057 */
1058 static struct llinfo_arp *
1059 arplookup(in_addr_t addr, boolean_t create, boolean_t generate_report,
1060 boolean_t proxy)
1061 {
1062 struct rtentry *rt;
1063 struct sockaddr_inarp sin = { sizeof sin, AF_INET };
1064 const char *why = NULL;
1065
1066 sin.sin_addr.s_addr = addr;
1067 sin.sin_other = proxy ? SIN_PROXY : 0;
1068 if (create) {
1069 rt = _rtlookup((struct sockaddr *)&sin,
1070 generate_report, RTL_DOCLONE);
1071 } else {
1072 rt = rtpurelookup((struct sockaddr *)&sin);
1073 }
1074 if (rt == NULL)
1075 return (NULL);
1076 rt->rt_refcnt--;
1077
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";
1084
1085 if (why) {
1086 if (create) {
1087 log(LOG_DEBUG, "arplookup %s failed: %s\n",
1088 inet_ntoa(sin.sin_addr), why);
1089 }
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);
1094 }
1095 return (NULL);
1096 }
1097 return (rt->rt_llinfo);
1098 }
1099
1100 void
1101 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
1102 {
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));
1106 }
1107 ifa->ifa_rtrequest = arp_rtrequest;
1108 ifa->ifa_flags |= RTF_CLONING;
1109 }
1110
1111 void
1112 arp_iainit(struct ifnet *ifp, const struct in_addr *addr, const u_char *enaddr)
1113 {
1114 if (addr->s_addr != INADDR_ANY)
1115 arprequest_async(ifp, addr, addr, enaddr);
1116 }
1117
1118 static void
1119 arp_init(void)
1120 {
1121 uint32_t flags;
1122 int cpu;
1123
1124 for (cpu = 0; cpu < ncpus2; cpu++)
1125 LIST_INIT(&llinfo_arp_list[cpu]);
1126
1127 if (arp_mpsafe) {
1128 flags = NETISR_FLAG_MPSAFE;
1129 kprintf("arp: MPSAFE\n");
1130 } else {
1131 flags = NETISR_FLAG_NOTMPSAFE;
1132 }
1133 netisr_register(NETISR_ARP, cpu0_portfn, pktinfo_portfn_cpu0,
1134 arpintr, flags);
1135 }
1136
1137 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
Cache object: ed40705abdcba1a5e188728c29d255c3
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