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("$FreeBSD$");
40
41 #include "opt_inet.h"
42
43 #include <sys/param.h>
44 #include <sys/kernel.h>
45 #include <sys/lock.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/rmlock.h>
53 #include <sys/socket.h>
54 #include <sys/syslog.h>
55
56 #include <net/if.h>
57 #include <net/if_var.h>
58 #include <net/if_dl.h>
59 #include <net/if_types.h>
60 #include <net/netisr.h>
61 #include <net/ethernet.h>
62 #include <net/route.h>
63 #include <net/vnet.h>
64
65 #include <netinet/in.h>
66 #include <netinet/in_fib.h>
67 #include <netinet/in_var.h>
68 #include <net/if_llatbl.h>
69 #include <netinet/if_ether.h>
70 #ifdef INET
71 #include <netinet/ip_carp.h>
72 #endif
73
74 #include <security/mac/mac_framework.h>
75
76 #define SIN(s) ((const struct sockaddr_in *)(s))
77
78 static struct timeval arp_lastlog;
79 static int arp_curpps;
80 static int arp_maxpps = 1;
81
82 /* Simple ARP state machine */
83 enum arp_llinfo_state {
84 ARP_LLINFO_INCOMPLETE = 0, /* No LLE data */
85 ARP_LLINFO_REACHABLE, /* LLE is valid */
86 ARP_LLINFO_VERIFY, /* LLE is valid, need refresh */
87 ARP_LLINFO_DELETED, /* LLE is deleted */
88 };
89
90 SYSCTL_DECL(_net_link_ether);
91 static SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
92 static SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
93
94 /* timer values */
95 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20
96 * minutes */
97 static VNET_DEFINE(int, arp_maxtries) = 5;
98 static VNET_DEFINE(int, arp_proxyall) = 0;
99 static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for
100 * 20 seconds */
101 static VNET_DEFINE(int, arpt_rexmit) = 1; /* retransmit arp entries, sec*/
102 VNET_PCPUSTAT_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */
103 VNET_PCPUSTAT_SYSINIT(arpstat);
104
105 #ifdef VIMAGE
106 VNET_PCPUSTAT_SYSUNINIT(arpstat);
107 #endif /* VIMAGE */
108
109 static VNET_DEFINE(int, arp_maxhold) = 1;
110
111 #define V_arpt_keep VNET(arpt_keep)
112 #define V_arpt_down VNET(arpt_down)
113 #define V_arpt_rexmit VNET(arpt_rexmit)
114 #define V_arp_maxtries VNET(arp_maxtries)
115 #define V_arp_proxyall VNET(arp_proxyall)
116 #define V_arp_maxhold VNET(arp_maxhold)
117
118 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_VNET | CTLFLAG_RW,
119 &VNET_NAME(arpt_keep), 0,
120 "ARP entry lifetime in seconds");
121 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_VNET | CTLFLAG_RW,
122 &VNET_NAME(arp_maxtries), 0,
123 "ARP resolution attempts before returning error");
124 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_VNET | CTLFLAG_RW,
125 &VNET_NAME(arp_proxyall), 0,
126 "Enable proxy ARP for all suitable requests");
127 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, wait, CTLFLAG_VNET | CTLFLAG_RW,
128 &VNET_NAME(arpt_down), 0,
129 "Incomplete ARP entry lifetime in seconds");
130 SYSCTL_VNET_PCPUSTAT(_net_link_ether_arp, OID_AUTO, stats, struct arpstat,
131 arpstat, "ARP statistics (struct arpstat, net/if_arp.h)");
132 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxhold, CTLFLAG_VNET | CTLFLAG_RW,
133 &VNET_NAME(arp_maxhold), 0,
134 "Number of packets to hold per ARP entry");
135 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_log_per_second,
136 CTLFLAG_RW, &arp_maxpps, 0,
137 "Maximum number of remotely triggered ARP messages that can be "
138 "logged per second");
139
140 #define ARP_LOG(pri, ...) do { \
141 if (ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \
142 log((pri), "arp: " __VA_ARGS__); \
143 } while (0)
144
145
146 static void arp_init(void);
147 static void arpintr(struct mbuf *);
148 static void arptimer(void *);
149 #ifdef INET
150 static void in_arpinput(struct mbuf *);
151 #endif
152
153 static void arp_check_update_lle(struct arphdr *ah, struct in_addr isaddr,
154 struct ifnet *ifp, int bridged, struct llentry *la);
155 static void arp_mark_lle_reachable(struct llentry *la);
156 static void arp_iflladdr(void *arg __unused, struct ifnet *ifp);
157
158 static eventhandler_tag iflladdr_tag;
159
160 static const struct netisr_handler arp_nh = {
161 .nh_name = "arp",
162 .nh_handler = arpintr,
163 .nh_proto = NETISR_ARP,
164 .nh_policy = NETISR_POLICY_SOURCE,
165 };
166
167 /*
168 * Timeout routine. Age arp_tab entries periodically.
169 */
170 static void
arptimer(void * arg)171 arptimer(void *arg)
172 {
173 struct llentry *lle = (struct llentry *)arg;
174 struct ifnet *ifp;
175 int r_skip_req;
176
177 if (lle->la_flags & LLE_STATIC) {
178 return;
179 }
180 LLE_WLOCK(lle);
181 if (callout_pending(&lle->lle_timer)) {
182 /*
183 * Here we are a bit odd here in the treatment of
184 * active/pending. If the pending bit is set, it got
185 * rescheduled before I ran. The active
186 * bit we ignore, since if it was stopped
187 * in ll_tablefree() and was currently running
188 * it would have return 0 so the code would
189 * not have deleted it since the callout could
190 * not be stopped so we want to go through
191 * with the delete here now. If the callout
192 * was restarted, the pending bit will be back on and
193 * we just want to bail since the callout_reset would
194 * return 1 and our reference would have been removed
195 * by arpresolve() below.
196 */
197 LLE_WUNLOCK(lle);
198 return;
199 }
200 ifp = lle->lle_tbl->llt_ifp;
201 CURVNET_SET(ifp->if_vnet);
202
203 switch (lle->ln_state) {
204 case ARP_LLINFO_REACHABLE:
205
206 /*
207 * Expiration time is approaching.
208 * Let's try to refresh entry if it is still
209 * in use.
210 *
211 * Set r_skip_req to get feedback from
212 * fast path. Change state and re-schedule
213 * ourselves.
214 */
215 LLE_REQ_LOCK(lle);
216 lle->r_skip_req = 1;
217 LLE_REQ_UNLOCK(lle);
218 lle->ln_state = ARP_LLINFO_VERIFY;
219 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit);
220 LLE_WUNLOCK(lle);
221 CURVNET_RESTORE();
222 return;
223 case ARP_LLINFO_VERIFY:
224 LLE_REQ_LOCK(lle);
225 r_skip_req = lle->r_skip_req;
226 LLE_REQ_UNLOCK(lle);
227
228 if (r_skip_req == 0 && lle->la_preempt > 0) {
229 /* Entry was used, issue refresh request */
230 struct in_addr dst;
231 dst = lle->r_l3addr.addr4;
232 lle->la_preempt--;
233 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit);
234 LLE_WUNLOCK(lle);
235 arprequest(ifp, NULL, &dst, NULL);
236 CURVNET_RESTORE();
237 return;
238 }
239 /* Nothing happened. Reschedule if not too late */
240 if (lle->la_expire > time_uptime) {
241 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit);
242 LLE_WUNLOCK(lle);
243 CURVNET_RESTORE();
244 return;
245 }
246 break;
247 case ARP_LLINFO_INCOMPLETE:
248 case ARP_LLINFO_DELETED:
249 break;
250 }
251
252 if ((lle->la_flags & LLE_DELETED) == 0) {
253 int evt;
254
255 if (lle->la_flags & LLE_VALID)
256 evt = LLENTRY_EXPIRED;
257 else
258 evt = LLENTRY_TIMEDOUT;
259 EVENTHANDLER_INVOKE(lle_event, lle, evt);
260 }
261
262 callout_stop(&lle->lle_timer);
263
264 /* XXX: LOR avoidance. We still have ref on lle. */
265 LLE_WUNLOCK(lle);
266 IF_AFDATA_LOCK(ifp);
267 LLE_WLOCK(lle);
268
269 /* Guard against race with other llentry_free(). */
270 if (lle->la_flags & LLE_LINKED) {
271 LLE_REMREF(lle);
272 lltable_unlink_entry(lle->lle_tbl, lle);
273 }
274 IF_AFDATA_UNLOCK(ifp);
275
276 size_t pkts_dropped = llentry_free(lle);
277
278 ARPSTAT_ADD(dropped, pkts_dropped);
279 ARPSTAT_INC(timeouts);
280
281 CURVNET_RESTORE();
282 }
283
284 /*
285 * Stores link-layer header for @ifp in format suitable for if_output()
286 * into buffer @buf. Resulting header length is stored in @bufsize.
287 *
288 * Returns 0 on success.
289 */
290 static int
arp_fillheader(struct ifnet * ifp,struct arphdr * ah,int bcast,u_char * buf,size_t * bufsize)291 arp_fillheader(struct ifnet *ifp, struct arphdr *ah, int bcast, u_char *buf,
292 size_t *bufsize)
293 {
294 struct if_encap_req ereq;
295 int error;
296
297 bzero(buf, *bufsize);
298 bzero(&ereq, sizeof(ereq));
299 ereq.buf = buf;
300 ereq.bufsize = *bufsize;
301 ereq.rtype = IFENCAP_LL;
302 ereq.family = AF_ARP;
303 ereq.lladdr = ar_tha(ah);
304 ereq.hdata = (u_char *)ah;
305 if (bcast)
306 ereq.flags = IFENCAP_FLAG_BROADCAST;
307 error = ifp->if_requestencap(ifp, &ereq);
308 if (error == 0)
309 *bufsize = ereq.bufsize;
310
311 return (error);
312 }
313
314
315 /*
316 * Broadcast an ARP request. Caller specifies:
317 * - arp header source ip address
318 * - arp header target ip address
319 * - arp header source ethernet address
320 */
321 void
arprequest(struct ifnet * ifp,const struct in_addr * sip,const struct in_addr * tip,u_char * enaddr)322 arprequest(struct ifnet *ifp, const struct in_addr *sip,
323 const struct in_addr *tip, u_char *enaddr)
324 {
325 struct mbuf *m;
326 struct arphdr *ah;
327 struct sockaddr sa;
328 u_char *carpaddr = NULL;
329 uint8_t linkhdr[LLE_MAX_LINKHDR];
330 size_t linkhdrsize;
331 struct route ro;
332 int error;
333
334 if (sip == NULL) {
335 /*
336 * The caller did not supply a source address, try to find
337 * a compatible one among those assigned to this interface.
338 */
339 struct ifaddr *ifa;
340
341 IF_ADDR_RLOCK(ifp);
342 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
343 if (ifa->ifa_addr->sa_family != AF_INET)
344 continue;
345
346 if (ifa->ifa_carp) {
347 if ((*carp_iamatch_p)(ifa, &carpaddr) == 0)
348 continue;
349 sip = &IA_SIN(ifa)->sin_addr;
350 } else {
351 carpaddr = NULL;
352 sip = &IA_SIN(ifa)->sin_addr;
353 }
354
355 if (0 == ((sip->s_addr ^ tip->s_addr) &
356 IA_MASKSIN(ifa)->sin_addr.s_addr))
357 break; /* found it. */
358 }
359 IF_ADDR_RUNLOCK(ifp);
360 if (sip == NULL) {
361 printf("%s: cannot find matching address\n", __func__);
362 return;
363 }
364 }
365 if (enaddr == NULL)
366 enaddr = carpaddr ? carpaddr : (u_char *)IF_LLADDR(ifp);
367
368 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL)
369 return;
370 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) +
371 2 * ifp->if_addrlen;
372 m->m_pkthdr.len = m->m_len;
373 M_ALIGN(m, m->m_len);
374 ah = mtod(m, struct arphdr *);
375 bzero((caddr_t)ah, m->m_len);
376 #ifdef MAC
377 mac_netinet_arp_send(ifp, m);
378 #endif
379 ah->ar_pro = htons(ETHERTYPE_IP);
380 ah->ar_hln = ifp->if_addrlen; /* hardware address length */
381 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */
382 ah->ar_op = htons(ARPOP_REQUEST);
383 bcopy(enaddr, ar_sha(ah), ah->ar_hln);
384 bcopy(sip, ar_spa(ah), ah->ar_pln);
385 bcopy(tip, ar_tpa(ah), ah->ar_pln);
386 sa.sa_family = AF_ARP;
387 sa.sa_len = 2;
388
389 /* Calculate link header for sending frame */
390 bzero(&ro, sizeof(ro));
391 linkhdrsize = sizeof(linkhdr);
392 error = arp_fillheader(ifp, ah, 1, linkhdr, &linkhdrsize);
393 if (error != 0 && error != EAFNOSUPPORT) {
394 ARP_LOG(LOG_ERR, "Failed to calculate ARP header on %s: %d\n",
395 if_name(ifp), error);
396 return;
397 }
398
399 ro.ro_prepend = linkhdr;
400 ro.ro_plen = linkhdrsize;
401 ro.ro_flags = 0;
402
403 m->m_flags |= M_BCAST;
404 m_clrprotoflags(m); /* Avoid confusing lower layers. */
405 (*ifp->if_output)(ifp, m, &sa, &ro);
406 ARPSTAT_INC(txrequests);
407 }
408
409
410 /*
411 * Resolve an IP address into an ethernet address - heavy version.
412 * Used internally by arpresolve().
413 * We have already checked than we can't use existing lle without
414 * modification so we have to acquire LLE_EXCLUSIVE lle lock.
415 *
416 * On success, desten and flags are filled in and the function returns 0;
417 * If the packet must be held pending resolution, we return EWOULDBLOCK
418 * On other errors, we return the corresponding error code.
419 * Note that m_freem() handles NULL.
420 */
421 static int
arpresolve_full(struct ifnet * ifp,int is_gw,int flags,struct mbuf * m,const struct sockaddr * dst,u_char * desten,uint32_t * pflags)422 arpresolve_full(struct ifnet *ifp, int is_gw, int flags, struct mbuf *m,
423 const struct sockaddr *dst, u_char *desten, uint32_t *pflags)
424 {
425 struct llentry *la = NULL, *la_tmp;
426 struct mbuf *curr = NULL;
427 struct mbuf *next = NULL;
428 int error, renew;
429 char *lladdr;
430 int ll_len;
431
432 if (pflags != NULL)
433 *pflags = 0;
434
435 if ((flags & LLE_CREATE) == 0) {
436 IF_AFDATA_RLOCK(ifp);
437 la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
438 IF_AFDATA_RUNLOCK(ifp);
439 }
440 if (la == NULL && (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0) {
441 la = lltable_alloc_entry(LLTABLE(ifp), 0, dst);
442 if (la == NULL) {
443 log(LOG_DEBUG,
444 "arpresolve: can't allocate llinfo for %s on %s\n",
445 inet_ntoa(SIN(dst)->sin_addr), if_name(ifp));
446 m_freem(m);
447 return (EINVAL);
448 }
449
450 IF_AFDATA_WLOCK(ifp);
451 LLE_WLOCK(la);
452 la_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
453 /* Prefer ANY existing lle over newly-created one */
454 if (la_tmp == NULL)
455 lltable_link_entry(LLTABLE(ifp), la);
456 IF_AFDATA_WUNLOCK(ifp);
457 if (la_tmp != NULL) {
458 lltable_free_entry(LLTABLE(ifp), la);
459 la = la_tmp;
460 }
461 }
462 if (la == NULL) {
463 m_freem(m);
464 return (EINVAL);
465 }
466
467 if ((la->la_flags & LLE_VALID) &&
468 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) {
469 if (flags & LLE_ADDRONLY) {
470 lladdr = la->ll_addr;
471 ll_len = ifp->if_addrlen;
472 } else {
473 lladdr = la->r_linkdata;
474 ll_len = la->r_hdrlen;
475 }
476 bcopy(lladdr, desten, ll_len);
477
478 /* Check if we have feedback request from arptimer() */
479 if (la->r_skip_req != 0) {
480 LLE_REQ_LOCK(la);
481 la->r_skip_req = 0; /* Notify that entry was used */
482 LLE_REQ_UNLOCK(la);
483 }
484 if (pflags != NULL)
485 *pflags = la->la_flags & (LLE_VALID|LLE_IFADDR);
486 LLE_WUNLOCK(la);
487 return (0);
488 }
489
490 renew = (la->la_asked == 0 || la->la_expire != time_uptime);
491 /*
492 * There is an arptab entry, but no ethernet address
493 * response yet. Add the mbuf to the list, dropping
494 * the oldest packet if we have exceeded the system
495 * setting.
496 */
497 if (m != NULL) {
498 if (la->la_numheld >= V_arp_maxhold) {
499 if (la->la_hold != NULL) {
500 next = la->la_hold->m_nextpkt;
501 m_freem(la->la_hold);
502 la->la_hold = next;
503 la->la_numheld--;
504 ARPSTAT_INC(dropped);
505 }
506 }
507 if (la->la_hold != NULL) {
508 curr = la->la_hold;
509 while (curr->m_nextpkt != NULL)
510 curr = curr->m_nextpkt;
511 curr->m_nextpkt = m;
512 } else
513 la->la_hold = m;
514 la->la_numheld++;
515 }
516 /*
517 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It
518 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH
519 * if we have already sent arp_maxtries ARP requests. Retransmit the
520 * ARP request, but not faster than one request per second.
521 */
522 if (la->la_asked < V_arp_maxtries)
523 error = EWOULDBLOCK; /* First request. */
524 else
525 error = is_gw != 0 ? EHOSTUNREACH : EHOSTDOWN;
526
527 if (renew) {
528 int canceled;
529
530 LLE_ADDREF(la);
531 la->la_expire = time_uptime;
532 canceled = callout_reset(&la->lle_timer, hz * V_arpt_down,
533 arptimer, la);
534 if (canceled)
535 LLE_REMREF(la);
536 la->la_asked++;
537 LLE_WUNLOCK(la);
538 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL);
539 return (error);
540 }
541
542 LLE_WUNLOCK(la);
543 return (error);
544 }
545
546 /*
547 * Resolve an IP address into an ethernet address.
548 */
549 int
arpresolve_addr(struct ifnet * ifp,int flags,const struct sockaddr * dst,char * desten,uint32_t * pflags)550 arpresolve_addr(struct ifnet *ifp, int flags, const struct sockaddr *dst,
551 char *desten, uint32_t *pflags)
552 {
553 int error;
554
555 flags |= LLE_ADDRONLY;
556 error = arpresolve_full(ifp, 0, flags, NULL, dst, desten, pflags);
557 return (error);
558 }
559
560 /*
561 * Lookups link header based on an IP address.
562 * On input:
563 * ifp is the interface we use
564 * is_gw != 0 if @dst represents gateway to some destination
565 * m is the mbuf. May be NULL if we don't have a packet.
566 * dst is the next hop,
567 * desten is the storage to put LL header.
568 * flags returns lle entry flags.
569 * flags returns subset of lle flags: LLE_VALID | LLE_IFADDR
570 *
571 * On success, full/partial link header and flags are filled in and
572 * the function returns 0.
573 * If the packet must be held pending resolution, we return EWOULDBLOCK
574 * On other errors, we return the corresponding error code.
575 * Note that m_freem() handles NULL.
576 */
577 int
arpresolve(struct ifnet * ifp,int is_gw,struct mbuf * m,const struct sockaddr * dst,u_char * desten,uint32_t * pflags)578 arpresolve(struct ifnet *ifp, int is_gw, struct mbuf *m,
579 const struct sockaddr *dst, u_char *desten, uint32_t *pflags)
580 {
581 struct llentry *la = 0;
582
583 if (pflags != NULL)
584 *pflags = 0;
585
586 if (m != NULL) {
587 if (m->m_flags & M_BCAST) {
588 /* broadcast */
589 (void)memcpy(desten,
590 ifp->if_broadcastaddr, ifp->if_addrlen);
591 return (0);
592 }
593 if (m->m_flags & M_MCAST) {
594 /* multicast */
595 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
596 return (0);
597 }
598 }
599
600 IF_AFDATA_RLOCK(ifp);
601 la = lla_lookup(LLTABLE(ifp), LLE_UNLOCKED, dst);
602 if (la != NULL && (la->r_flags & RLLE_VALID) != 0) {
603 /* Entry found, let's copy lle info */
604 bcopy(la->r_linkdata, desten, la->r_hdrlen);
605 if (pflags != NULL)
606 *pflags = LLE_VALID | (la->r_flags & RLLE_IFADDR);
607 /* Check if we have feedback request from arptimer() */
608 if (la->r_skip_req != 0) {
609 LLE_REQ_LOCK(la);
610 la->r_skip_req = 0; /* Notify that entry was used */
611 LLE_REQ_UNLOCK(la);
612 }
613 IF_AFDATA_RUNLOCK(ifp);
614
615 return (0);
616 }
617 IF_AFDATA_RUNLOCK(ifp);
618
619 return (arpresolve_full(ifp, is_gw, la == NULL ? LLE_CREATE : 0, m, dst,
620 desten, pflags));
621 }
622
623 /*
624 * Common length and type checks are done here,
625 * then the protocol-specific routine is called.
626 */
627 static void
arpintr(struct mbuf * m)628 arpintr(struct mbuf *m)
629 {
630 struct arphdr *ar;
631 struct ifnet *ifp;
632 char *layer;
633 int hlen;
634
635 ifp = m->m_pkthdr.rcvif;
636
637 if (m->m_len < sizeof(struct arphdr) &&
638 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
639 ARP_LOG(LOG_NOTICE, "packet with short header received on %s\n",
640 if_name(ifp));
641 return;
642 }
643 ar = mtod(m, struct arphdr *);
644
645 /* Check if length is sufficient */
646 if (m->m_len < arphdr_len(ar)) {
647 m = m_pullup(m, arphdr_len(ar));
648 if (m == NULL) {
649 ARP_LOG(LOG_NOTICE, "short packet received on %s\n",
650 if_name(ifp));
651 return;
652 }
653 ar = mtod(m, struct arphdr *);
654 }
655
656 hlen = 0;
657 layer = "";
658 switch (ntohs(ar->ar_hrd)) {
659 case ARPHRD_ETHER:
660 hlen = ETHER_ADDR_LEN; /* RFC 826 */
661 layer = "ethernet";
662 break;
663 case ARPHRD_IEEE802:
664 hlen = 6; /* RFC 1390, FDDI_ADDR_LEN */
665 layer = "fddi";
666 break;
667 case ARPHRD_ARCNET:
668 hlen = 1; /* RFC 1201, ARC_ADDR_LEN */
669 layer = "arcnet";
670 break;
671 case ARPHRD_INFINIBAND:
672 hlen = 20; /* RFC 4391, INFINIBAND_ALEN */
673 layer = "infiniband";
674 break;
675 case ARPHRD_IEEE1394:
676 hlen = 0; /* SHALL be 16 */ /* RFC 2734 */
677 layer = "firewire";
678
679 /*
680 * Restrict too long hardware addresses.
681 * Currently we are capable of handling 20-byte
682 * addresses ( sizeof(lle->ll_addr) )
683 */
684 if (ar->ar_hln >= 20)
685 hlen = 16;
686 break;
687 default:
688 ARP_LOG(LOG_NOTICE,
689 "packet with unknown hardware format 0x%02d received on "
690 "%s\n", ntohs(ar->ar_hrd), if_name(ifp));
691 m_freem(m);
692 return;
693 }
694
695 if (hlen != 0 && hlen != ar->ar_hln) {
696 ARP_LOG(LOG_NOTICE,
697 "packet with invalid %s address length %d received on %s\n",
698 layer, ar->ar_hln, if_name(ifp));
699 m_freem(m);
700 return;
701 }
702
703 ARPSTAT_INC(received);
704 switch (ntohs(ar->ar_pro)) {
705 #ifdef INET
706 case ETHERTYPE_IP:
707 in_arpinput(m);
708 return;
709 #endif
710 }
711 m_freem(m);
712 }
713
714 #ifdef INET
715 /*
716 * ARP for Internet protocols on 10 Mb/s Ethernet.
717 * Algorithm is that given in RFC 826.
718 * In addition, a sanity check is performed on the sender
719 * protocol address, to catch impersonators.
720 * We no longer handle negotiations for use of trailer protocol:
721 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
722 * along with IP replies if we wanted trailers sent to us,
723 * and also sent them in response to IP replies.
724 * This allowed either end to announce the desire to receive
725 * trailer packets.
726 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
727 * but formerly didn't normally send requests.
728 */
729 static int log_arp_wrong_iface = 1;
730 static int log_arp_movements = 1;
731 static int log_arp_permanent_modify = 1;
732 static int allow_multicast = 0;
733
734 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
735 &log_arp_wrong_iface, 0,
736 "log arp packets arriving on the wrong interface");
737 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW,
738 &log_arp_movements, 0,
739 "log arp replies from MACs different than the one in the cache");
740 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW,
741 &log_arp_permanent_modify, 0,
742 "log arp replies from MACs different than the one in the permanent arp entry");
743 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW,
744 &allow_multicast, 0, "accept multicast addresses");
745
746 static void
in_arpinput(struct mbuf * m)747 in_arpinput(struct mbuf *m)
748 {
749 struct rm_priotracker in_ifa_tracker;
750 struct arphdr *ah;
751 struct ifnet *ifp = m->m_pkthdr.rcvif;
752 struct llentry *la = NULL, *la_tmp;
753 struct ifaddr *ifa;
754 struct in_ifaddr *ia;
755 struct sockaddr sa;
756 struct in_addr isaddr, itaddr, myaddr;
757 u_int8_t *enaddr = NULL;
758 int op;
759 int bridged = 0, is_bridge = 0;
760 int carped;
761 struct sockaddr_in sin;
762 struct sockaddr *dst;
763 struct nhop4_basic nh4;
764 uint8_t linkhdr[LLE_MAX_LINKHDR];
765 struct route ro;
766 size_t linkhdrsize;
767 int lladdr_off;
768 int error;
769
770 sin.sin_len = sizeof(struct sockaddr_in);
771 sin.sin_family = AF_INET;
772 sin.sin_addr.s_addr = 0;
773
774 if (ifp->if_bridge)
775 bridged = 1;
776 if (ifp->if_type == IFT_BRIDGE)
777 is_bridge = 1;
778
779 /*
780 * We already have checked that mbuf contains enough contiguous data
781 * to hold entire arp message according to the arp header.
782 */
783 ah = mtod(m, struct arphdr *);
784
785 /*
786 * ARP is only for IPv4 so we can reject packets with
787 * a protocol length not equal to an IPv4 address.
788 */
789 if (ah->ar_pln != sizeof(struct in_addr)) {
790 ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n",
791 sizeof(struct in_addr));
792 goto drop;
793 }
794
795 if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) {
796 ARP_LOG(LOG_NOTICE, "%*D is multicast\n",
797 ifp->if_addrlen, (u_char *)ar_sha(ah), ":");
798 goto drop;
799 }
800
801 op = ntohs(ah->ar_op);
802 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
803 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
804
805 if (op == ARPOP_REPLY)
806 ARPSTAT_INC(rxreplies);
807
808 /*
809 * For a bridge, we want to check the address irrespective
810 * of the receive interface. (This will change slightly
811 * when we have clusters of interfaces).
812 */
813 IN_IFADDR_RLOCK(&in_ifa_tracker);
814 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
815 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
816 ia->ia_ifp == ifp) &&
817 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr &&
818 (ia->ia_ifa.ifa_carp == NULL ||
819 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) {
820 ifa_ref(&ia->ia_ifa);
821 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
822 goto match;
823 }
824 }
825 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
826 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) ||
827 ia->ia_ifp == ifp) &&
828 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) {
829 ifa_ref(&ia->ia_ifa);
830 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
831 goto match;
832 }
833
834 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \
835 (ia->ia_ifp->if_bridge == ifp->if_softc && \
836 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \
837 addr == ia->ia_addr.sin_addr.s_addr)
838 /*
839 * Check the case when bridge shares its MAC address with
840 * some of its children, so packets are claimed by bridge
841 * itself (bridge_input() does it first), but they are really
842 * meant to be destined to the bridge member.
843 */
844 if (is_bridge) {
845 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) {
846 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) {
847 ifa_ref(&ia->ia_ifa);
848 ifp = ia->ia_ifp;
849 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
850 goto match;
851 }
852 }
853 }
854 #undef BDG_MEMBER_MATCHES_ARP
855 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
856
857 /*
858 * No match, use the first inet address on the receive interface
859 * as a dummy address for the rest of the function.
860 */
861 IF_ADDR_RLOCK(ifp);
862 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
863 if (ifa->ifa_addr->sa_family == AF_INET &&
864 (ifa->ifa_carp == NULL ||
865 (*carp_iamatch_p)(ifa, &enaddr))) {
866 ia = ifatoia(ifa);
867 ifa_ref(ifa);
868 IF_ADDR_RUNLOCK(ifp);
869 goto match;
870 }
871 IF_ADDR_RUNLOCK(ifp);
872
873 /*
874 * If bridging, fall back to using any inet address.
875 */
876 IN_IFADDR_RLOCK(&in_ifa_tracker);
877 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) {
878 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
879 goto drop;
880 }
881 ifa_ref(&ia->ia_ifa);
882 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
883 match:
884 if (!enaddr)
885 enaddr = (u_int8_t *)IF_LLADDR(ifp);
886 carped = (ia->ia_ifa.ifa_carp != NULL);
887 myaddr = ia->ia_addr.sin_addr;
888 ifa_free(&ia->ia_ifa);
889 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen))
890 goto drop; /* it's from me, ignore it. */
891 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) {
892 ARP_LOG(LOG_NOTICE, "link address is broadcast for IP address "
893 "%s!\n", inet_ntoa(isaddr));
894 goto drop;
895 }
896
897 if (ifp->if_addrlen != ah->ar_hln) {
898 ARP_LOG(LOG_WARNING, "from %*D: addr len: new %d, "
899 "i/f %d (ignored)\n", ifp->if_addrlen,
900 (u_char *) ar_sha(ah), ":", ah->ar_hln,
901 ifp->if_addrlen);
902 goto drop;
903 }
904
905 /*
906 * Warn if another host is using the same IP address, but only if the
907 * IP address isn't 0.0.0.0, which is used for DHCP only, in which
908 * case we suppress the warning to avoid false positive complaints of
909 * potential misconfiguration.
910 */
911 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr &&
912 myaddr.s_addr != 0) {
913 ARP_LOG(LOG_ERR, "%*D is using my IP address %s on %s!\n",
914 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
915 inet_ntoa(isaddr), ifp->if_xname);
916 itaddr = myaddr;
917 ARPSTAT_INC(dupips);
918 goto reply;
919 }
920 if (ifp->if_flags & IFF_STATICARP)
921 goto reply;
922
923 bzero(&sin, sizeof(sin));
924 sin.sin_len = sizeof(struct sockaddr_in);
925 sin.sin_family = AF_INET;
926 sin.sin_addr = isaddr;
927 dst = (struct sockaddr *)&sin;
928 IF_AFDATA_RLOCK(ifp);
929 la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
930 IF_AFDATA_RUNLOCK(ifp);
931 if (la != NULL)
932 arp_check_update_lle(ah, isaddr, ifp, bridged, la);
933 else if (itaddr.s_addr == myaddr.s_addr) {
934 /*
935 * Request/reply to our address, but no lle exists yet.
936 * Calculate full link prepend to use in lle.
937 */
938 linkhdrsize = sizeof(linkhdr);
939 if (lltable_calc_llheader(ifp, AF_INET, ar_sha(ah), linkhdr,
940 &linkhdrsize, &lladdr_off) != 0)
941 goto reply;
942
943 /* Allocate new entry */
944 la = lltable_alloc_entry(LLTABLE(ifp), 0, dst);
945 if (la == NULL) {
946
947 /*
948 * lle creation may fail if source address belongs
949 * to non-directly connected subnet. However, we
950 * will try to answer the request instead of dropping
951 * frame.
952 */
953 goto reply;
954 }
955 lltable_set_entry_addr(ifp, la, linkhdr, linkhdrsize,
956 lladdr_off);
957
958 IF_AFDATA_WLOCK(ifp);
959 LLE_WLOCK(la);
960 la_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
961
962 /*
963 * Check if lle still does not exists.
964 * If it does, that means that we either
965 * 1) have configured it explicitly, via
966 * 1a) 'arp -s' static entry or
967 * 1b) interface address static record
968 * or
969 * 2) it was the result of sending first packet to-host
970 * or
971 * 3) it was another arp reply packet we handled in
972 * different thread.
973 *
974 * In all cases except 3) we definitely need to prefer
975 * existing lle. For the sake of simplicity, prefer any
976 * existing lle over newly-create one.
977 */
978 if (la_tmp == NULL)
979 lltable_link_entry(LLTABLE(ifp), la);
980 IF_AFDATA_WUNLOCK(ifp);
981
982 if (la_tmp == NULL) {
983 arp_mark_lle_reachable(la);
984 LLE_WUNLOCK(la);
985 } else {
986 /* Free newly-create entry and handle packet */
987 lltable_free_entry(LLTABLE(ifp), la);
988 la = la_tmp;
989 la_tmp = NULL;
990 arp_check_update_lle(ah, isaddr, ifp, bridged, la);
991 /* arp_check_update_lle() returns @la unlocked */
992 }
993 la = NULL;
994 }
995 reply:
996 if (op != ARPOP_REQUEST)
997 goto drop;
998 ARPSTAT_INC(rxrequests);
999
1000 if (itaddr.s_addr == myaddr.s_addr) {
1001 /* Shortcut.. the receiving interface is the target. */
1002 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
1003 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
1004 } else {
1005 struct llentry *lle = NULL;
1006
1007 sin.sin_addr = itaddr;
1008 IF_AFDATA_RLOCK(ifp);
1009 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin);
1010 IF_AFDATA_RUNLOCK(ifp);
1011
1012 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) {
1013 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
1014 (void)memcpy(ar_sha(ah), lle->ll_addr, ah->ar_hln);
1015 LLE_RUNLOCK(lle);
1016 } else {
1017
1018 if (lle != NULL)
1019 LLE_RUNLOCK(lle);
1020
1021 if (!V_arp_proxyall)
1022 goto drop;
1023
1024 /* XXX MRT use table 0 for arp reply */
1025 if (fib4_lookup_nh_basic(0, itaddr, 0, 0, &nh4) != 0)
1026 goto drop;
1027
1028 /*
1029 * Don't send proxies for nodes on the same interface
1030 * as this one came out of, or we'll get into a fight
1031 * over who claims what Ether address.
1032 */
1033 if (nh4.nh_ifp == ifp)
1034 goto drop;
1035
1036 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
1037 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
1038
1039 /*
1040 * Also check that the node which sent the ARP packet
1041 * is on the interface we expect it to be on. This
1042 * avoids ARP chaos if an interface is connected to the
1043 * wrong network.
1044 */
1045
1046 /* XXX MRT use table 0 for arp checks */
1047 if (fib4_lookup_nh_basic(0, isaddr, 0, 0, &nh4) != 0)
1048 goto drop;
1049 if (nh4.nh_ifp != ifp) {
1050 ARP_LOG(LOG_INFO, "proxy: ignoring request"
1051 " from %s via %s\n",
1052 inet_ntoa(isaddr), ifp->if_xname);
1053 goto drop;
1054 }
1055
1056 #ifdef DEBUG_PROXY
1057 printf("arp: proxying for %s\n", inet_ntoa(itaddr));
1058 #endif
1059 }
1060 }
1061
1062 if (itaddr.s_addr == myaddr.s_addr &&
1063 IN_LINKLOCAL(ntohl(itaddr.s_addr))) {
1064 /* RFC 3927 link-local IPv4; always reply by broadcast. */
1065 #ifdef DEBUG_LINKLOCAL
1066 printf("arp: sending reply for link-local addr %s\n",
1067 inet_ntoa(itaddr));
1068 #endif
1069 m->m_flags |= M_BCAST;
1070 m->m_flags &= ~M_MCAST;
1071 } else {
1072 /* default behaviour; never reply by broadcast. */
1073 m->m_flags &= ~(M_BCAST|M_MCAST);
1074 }
1075 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
1076 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
1077 ah->ar_op = htons(ARPOP_REPLY);
1078 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
1079 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
1080 m->m_pkthdr.len = m->m_len;
1081 m->m_pkthdr.rcvif = NULL;
1082 sa.sa_family = AF_ARP;
1083 sa.sa_len = 2;
1084
1085 /* Calculate link header for sending frame */
1086 bzero(&ro, sizeof(ro));
1087 linkhdrsize = sizeof(linkhdr);
1088 error = arp_fillheader(ifp, ah, 0, linkhdr, &linkhdrsize);
1089
1090 /*
1091 * arp_fillheader() may fail due to lack of support inside encap request
1092 * routing. This is not necessary an error, AF_ARP can/should be handled
1093 * by if_output().
1094 */
1095 if (error != 0 && error != EAFNOSUPPORT) {
1096 ARP_LOG(LOG_ERR, "Failed to calculate ARP header on %s: %d\n",
1097 if_name(ifp), error);
1098 return;
1099 }
1100
1101 ro.ro_prepend = linkhdr;
1102 ro.ro_plen = linkhdrsize;
1103 ro.ro_flags = 0;
1104
1105 m_clrprotoflags(m); /* Avoid confusing lower layers. */
1106 (*ifp->if_output)(ifp, m, &sa, &ro);
1107 ARPSTAT_INC(txreplies);
1108 return;
1109
1110 drop:
1111 m_freem(m);
1112 }
1113 #endif
1114
1115 /*
1116 * Checks received arp data against existing @la.
1117 * Updates lle state/performs notification if necessary.
1118 */
1119 static void
arp_check_update_lle(struct arphdr * ah,struct in_addr isaddr,struct ifnet * ifp,int bridged,struct llentry * la)1120 arp_check_update_lle(struct arphdr *ah, struct in_addr isaddr, struct ifnet *ifp,
1121 int bridged, struct llentry *la)
1122 {
1123 struct sockaddr sa;
1124 struct mbuf *m_hold, *m_hold_next;
1125 uint8_t linkhdr[LLE_MAX_LINKHDR];
1126 size_t linkhdrsize;
1127 int lladdr_off;
1128
1129 LLE_WLOCK_ASSERT(la);
1130
1131 /* the following is not an error when doing bridging */
1132 if (!bridged && la->lle_tbl->llt_ifp != ifp) {
1133 if (log_arp_wrong_iface)
1134 ARP_LOG(LOG_WARNING, "%s is on %s "
1135 "but got reply from %*D on %s\n",
1136 inet_ntoa(isaddr),
1137 la->lle_tbl->llt_ifp->if_xname,
1138 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
1139 ifp->if_xname);
1140 LLE_WUNLOCK(la);
1141 return;
1142 }
1143 if ((la->la_flags & LLE_VALID) &&
1144 bcmp(ar_sha(ah), la->ll_addr, ifp->if_addrlen)) {
1145 if (la->la_flags & LLE_STATIC) {
1146 LLE_WUNLOCK(la);
1147 if (log_arp_permanent_modify)
1148 ARP_LOG(LOG_ERR,
1149 "%*D attempts to modify "
1150 "permanent entry for %s on %s\n",
1151 ifp->if_addrlen,
1152 (u_char *)ar_sha(ah), ":",
1153 inet_ntoa(isaddr), ifp->if_xname);
1154 return;
1155 }
1156 if (log_arp_movements) {
1157 ARP_LOG(LOG_INFO, "%s moved from %*D "
1158 "to %*D on %s\n",
1159 inet_ntoa(isaddr),
1160 ifp->if_addrlen,
1161 (u_char *)&la->ll_addr, ":",
1162 ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
1163 ifp->if_xname);
1164 }
1165 }
1166
1167 /* Calculate full link prepend to use in lle */
1168 linkhdrsize = sizeof(linkhdr);
1169 if (lltable_calc_llheader(ifp, AF_INET, ar_sha(ah), linkhdr,
1170 &linkhdrsize, &lladdr_off) != 0)
1171 return;
1172
1173 /* Check if something has changed */
1174 if (memcmp(la->r_linkdata, linkhdr, linkhdrsize) != 0 ||
1175 (la->la_flags & LLE_VALID) == 0) {
1176 /* Try to perform LLE update */
1177 if (lltable_try_set_entry_addr(ifp, la, linkhdr, linkhdrsize,
1178 lladdr_off) == 0)
1179 return;
1180
1181 /* Clear fast path feedback request if set */
1182 la->r_skip_req = 0;
1183 }
1184
1185 arp_mark_lle_reachable(la);
1186
1187 /*
1188 * The packets are all freed within the call to the output
1189 * routine.
1190 *
1191 * NB: The lock MUST be released before the call to the
1192 * output routine.
1193 */
1194 if (la->la_hold != NULL) {
1195 m_hold = la->la_hold;
1196 la->la_hold = NULL;
1197 la->la_numheld = 0;
1198 lltable_fill_sa_entry(la, &sa);
1199 LLE_WUNLOCK(la);
1200 for (; m_hold != NULL; m_hold = m_hold_next) {
1201 m_hold_next = m_hold->m_nextpkt;
1202 m_hold->m_nextpkt = NULL;
1203 /* Avoid confusing lower layers. */
1204 m_clrprotoflags(m_hold);
1205 (*ifp->if_output)(ifp, m_hold, &sa, NULL);
1206 }
1207 } else
1208 LLE_WUNLOCK(la);
1209 }
1210
1211 static void
arp_mark_lle_reachable(struct llentry * la)1212 arp_mark_lle_reachable(struct llentry *la)
1213 {
1214 int canceled, wtime;
1215
1216 LLE_WLOCK_ASSERT(la);
1217
1218 la->ln_state = ARP_LLINFO_REACHABLE;
1219 EVENTHANDLER_INVOKE(lle_event, la, LLENTRY_RESOLVED);
1220
1221 if (!(la->la_flags & LLE_STATIC)) {
1222 LLE_ADDREF(la);
1223 la->la_expire = time_uptime + V_arpt_keep;
1224 wtime = V_arpt_keep - V_arp_maxtries * V_arpt_rexmit;
1225 if (wtime < 0)
1226 wtime = V_arpt_keep;
1227 canceled = callout_reset(&la->lle_timer,
1228 hz * wtime, arptimer, la);
1229 if (canceled)
1230 LLE_REMREF(la);
1231 }
1232 la->la_asked = 0;
1233 la->la_preempt = V_arp_maxtries;
1234 }
1235
1236 /*
1237 * Add pernament link-layer record for given interface address.
1238 */
1239 static __noinline void
arp_add_ifa_lle(struct ifnet * ifp,const struct sockaddr * dst)1240 arp_add_ifa_lle(struct ifnet *ifp, const struct sockaddr *dst)
1241 {
1242 struct llentry *lle, *lle_tmp;
1243
1244 /*
1245 * Interface address LLE record is considered static
1246 * because kernel code relies on LLE_STATIC flag to check
1247 * if these entries can be rewriten by arp updates.
1248 */
1249 lle = lltable_alloc_entry(LLTABLE(ifp), LLE_IFADDR | LLE_STATIC, dst);
1250 if (lle == NULL) {
1251 log(LOG_INFO, "arp_ifinit: cannot create arp "
1252 "entry for interface address\n");
1253 return;
1254 }
1255
1256 IF_AFDATA_WLOCK(ifp);
1257 LLE_WLOCK(lle);
1258 /* Unlink any entry if exists */
1259 lle_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst);
1260 if (lle_tmp != NULL)
1261 lltable_unlink_entry(LLTABLE(ifp), lle_tmp);
1262
1263 lltable_link_entry(LLTABLE(ifp), lle);
1264 IF_AFDATA_WUNLOCK(ifp);
1265
1266 if (lle_tmp != NULL)
1267 EVENTHANDLER_INVOKE(lle_event, lle_tmp, LLENTRY_EXPIRED);
1268
1269 EVENTHANDLER_INVOKE(lle_event, lle, LLENTRY_RESOLVED);
1270 LLE_WUNLOCK(lle);
1271 if (lle_tmp != NULL)
1272 lltable_free_entry(LLTABLE(ifp), lle_tmp);
1273 }
1274
1275 void
arp_ifinit(struct ifnet * ifp,struct ifaddr * ifa)1276 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa)
1277 {
1278 const struct sockaddr_in *dst_in;
1279 const struct sockaddr *dst;
1280
1281 if (ifa->ifa_carp != NULL)
1282 return;
1283
1284 dst = ifa->ifa_addr;
1285 dst_in = (const struct sockaddr_in *)dst;
1286
1287 if (ntohl(dst_in->sin_addr.s_addr) == INADDR_ANY)
1288 return;
1289 arp_announce_ifaddr(ifp, dst_in->sin_addr, IF_LLADDR(ifp));
1290
1291 arp_add_ifa_lle(ifp, dst);
1292 }
1293
1294 void
arp_announce_ifaddr(struct ifnet * ifp,struct in_addr addr,u_char * enaddr)1295 arp_announce_ifaddr(struct ifnet *ifp, struct in_addr addr, u_char *enaddr)
1296 {
1297
1298 if (ntohl(addr.s_addr) != INADDR_ANY)
1299 arprequest(ifp, &addr, &addr, enaddr);
1300 }
1301
1302 /*
1303 * Sends gratuitous ARPs for each ifaddr to notify other
1304 * nodes about the address change.
1305 */
1306 static __noinline void
arp_handle_ifllchange(struct ifnet * ifp)1307 arp_handle_ifllchange(struct ifnet *ifp)
1308 {
1309 struct ifaddr *ifa;
1310
1311 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1312 if (ifa->ifa_addr->sa_family == AF_INET)
1313 arp_ifinit(ifp, ifa);
1314 }
1315 }
1316
1317
1318 /*
1319 * A handler for interface link layer address change event.
1320 */
1321 static void
arp_iflladdr(void * arg __unused,struct ifnet * ifp)1322 arp_iflladdr(void *arg __unused, struct ifnet *ifp)
1323 {
1324
1325 lltable_update_ifaddr(LLTABLE(ifp));
1326
1327 if ((ifp->if_flags & IFF_UP) != 0)
1328 arp_handle_ifllchange(ifp);
1329 }
1330
1331 static void
arp_init(void)1332 arp_init(void)
1333 {
1334
1335 netisr_register(&arp_nh);
1336 if (IS_DEFAULT_VNET(curvnet))
1337 iflladdr_tag = EVENTHANDLER_REGISTER(iflladdr_event,
1338 arp_iflladdr, NULL, EVENTHANDLER_PRI_ANY);
1339 }
1340 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
1341