if_ether.c revision 12877
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 * $Id: if_ether.c,v 1.23 1995/12/14 09:53:37 phk 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 <sys/param.h> 44#include <sys/kernel.h> 45#include <sys/sysctl.h> 46#include <sys/queue.h> 47#include <sys/systm.h> 48#include <sys/mbuf.h> 49#include <sys/malloc.h> 50#include <sys/syslog.h> 51 52#include <net/if.h> 53#include <net/if_dl.h> 54#include <net/route.h> 55#include <net/netisr.h> 56 57#include <netinet/in.h> 58#include <netinet/in_var.h> 59#include <netinet/if_ether.h> 60 61#define SIN(s) ((struct sockaddr_in *)s) 62#define SDL(s) ((struct sockaddr_dl *)s) 63 64SYSCTL_NODE(_net, OID_AUTO, arp, CTLFLAG_RW, 0, ""); 65 66/* timer values */ 67static int arpt_prune = (5*60*1); 68 /* walk list every 5 minutes */ 69SYSCTL_INT(_net_arp, OID_AUTO, t_prune, CTLFLAG_RW, &arpt_prune, 0, ""); 70 71static int arpt_keep = (20*60); 72 /* once resolved, good for 20 more minutes */ 73SYSCTL_INT(_net_arp, OID_AUTO, t_keep, CTLFLAG_RW, &arpt_keep, 0, ""); 74 75static int arpt_down = 20; 76 /* once declared down, don't send for 20 secs */ 77SYSCTL_INT(_net_arp, OID_AUTO, t_down, CTLFLAG_RW, &arpt_down, 0, ""); 78 79#define rt_expire rt_rmx.rmx_expire 80 81struct llinfo_arp { 82 LIST_ENTRY(llinfo_arp) la_le; 83 struct rtentry *la_rt; 84 struct mbuf *la_hold; /* last packet until resolved/timeout */ 85 long la_asked; /* last time we QUERIED for this addr */ 86#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 87}; 88 89static LIST_HEAD(, llinfo_arp) llinfo_arp; 90 91struct ifqueue arpintrq = {0, 0, 0, 50}; 92static int arp_inuse, arp_allocated; 93 94static int arp_maxtries = 5; 95SYSCTL_INT(_net_arp, OID_AUTO, maxtries, CTLFLAG_RW, &arp_maxtries, 0, ""); 96 97static int useloopback = 1; 98 /* use loopback interface for local traffic */ 99SYSCTL_INT(_net_arp, OID_AUTO, useloopback, CTLFLAG_RW, &useloopback, 0, ""); 100 101static int arp_proxyall = 0; 102SYSCTL_INT(_net_arp, OID_AUTO, proxyall, CTLFLAG_RW, &arp_proxyall, 0, ""); 103 104static void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 105static void arprequest __P((struct arpcom *, u_long *, u_long *, u_char *)); 106static void arpintr __P((void)); 107static void arptfree __P((struct llinfo_arp *)); 108static void arptimer __P((void *)); 109static void arpwhohas __P((struct arpcom *ac, struct in_addr *addr)); 110static struct llinfo_arp 111 *arplookup __P((u_long, int, int)); 112static void in_arpinput __P((struct mbuf *)); 113 114/* 115 * Timeout routine. Age arp_tab entries periodically. 116 */ 117/* ARGSUSED */ 118static void 119arptimer(ignored_arg) 120 void *ignored_arg; 121{ 122 int s = splnet(); 123 register struct llinfo_arp *la = llinfo_arp.lh_first; 124 struct llinfo_arp *ola; 125 126 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 127 while ((ola = la) != 0) { 128 register struct rtentry *rt = la->la_rt; 129 la = la->la_le.le_next; 130 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 131 arptfree(ola); /* timer has expired, clear */ 132 } 133 splx(s); 134} 135 136/* 137 * Parallel to llc_rtrequest. 138 */ 139static void 140arp_rtrequest(req, rt, sa) 141 int req; 142 register struct rtentry *rt; 143 struct sockaddr *sa; 144{ 145 register struct sockaddr *gate = rt->rt_gateway; 146 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 147 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 148 static int arpinit_done; 149 150 if (!arpinit_done) { 151 arpinit_done = 1; 152 LIST_INIT(&llinfo_arp); 153 timeout(arptimer, (caddr_t)0, hz); 154 } 155 if (rt->rt_flags & RTF_GATEWAY) 156 return; 157 switch (req) { 158 159 case RTM_ADD: 160 /* 161 * XXX: If this is a manually added route to interface 162 * such as older version of routed or gated might provide, 163 * restore cloning bit. 164 */ 165 if ((rt->rt_flags & RTF_HOST) == 0 && 166 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 167 rt->rt_flags |= RTF_CLONING; 168 if (rt->rt_flags & RTF_CLONING) { 169 /* 170 * Case 1: This route should come from a route to iface. 171 */ 172 rt_setgate(rt, rt_key(rt), 173 (struct sockaddr *)&null_sdl); 174 gate = rt->rt_gateway; 175 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 176 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 177 rt->rt_expire = time.tv_sec; 178 break; 179 } 180 /* Announce a new entry if requested. */ 181 if (rt->rt_flags & RTF_ANNOUNCE) 182 arprequest((struct arpcom *)rt->rt_ifp, 183 &SIN(rt_key(rt))->sin_addr.s_addr, 184 &SIN(rt_key(rt))->sin_addr.s_addr, 185 (u_char *)LLADDR(SDL(gate))); 186 /*FALLTHROUGH*/ 187 case RTM_RESOLVE: 188 if (gate->sa_family != AF_LINK || 189 gate->sa_len < sizeof(null_sdl)) { 190 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 191 break; 192 } 193 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 194 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 195 if (la != 0) 196 break; /* This happens on a route change */ 197 /* 198 * Case 2: This route may come from cloning, or a manual route 199 * add with a LL address. 200 */ 201 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 202 rt->rt_llinfo = (caddr_t)la; 203 if (la == 0) { 204 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 205 break; 206 } 207 arp_inuse++, arp_allocated++; 208 Bzero(la, sizeof(*la)); 209 la->la_rt = rt; 210 rt->rt_flags |= RTF_LLINFO; 211 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 212 if (SIN(rt_key(rt))->sin_addr.s_addr == 213 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 214 /* 215 * This test used to be 216 * if (loif.if_flags & IFF_UP) 217 * It allowed local traffic to be forced 218 * through the hardware by configuring the loopback down. 219 * However, it causes problems during network configuration 220 * for boards that can't receive packets they send. 221 * It is now necessary to clear "useloopback" and remove 222 * the route to force traffic out to the hardware. 223 */ 224 rt->rt_expire = 0; 225 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 226 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 227 if (useloopback) 228 rt->rt_ifp = loif; 229 230 } 231 break; 232 233 case RTM_DELETE: 234 if (la == 0) 235 break; 236 arp_inuse--; 237 LIST_REMOVE(la, la_le); 238 rt->rt_llinfo = 0; 239 rt->rt_flags &= ~RTF_LLINFO; 240 if (la->la_hold) 241 m_freem(la->la_hold); 242 Free((caddr_t)la); 243 } 244} 245/* 246 * Broadcast an ARP packet, asking who has addr on interface ac. 247 */ 248static void 249arpwhohas(ac, addr) 250 struct arpcom *ac; 251 struct in_addr *addr; 252{ 253 arprequest(ac, &ac->ac_ipaddr.s_addr, &addr->s_addr, ac->ac_enaddr); 254} 255 256/* 257 * Broadcast an ARP request. Caller specifies: 258 * - arp header source ip address 259 * - arp header target ip address 260 * - arp header source ethernet address 261 */ 262static void 263arprequest(ac, sip, tip, enaddr) 264 register struct arpcom *ac; 265 register u_long *sip, *tip; 266 register u_char *enaddr; 267{ 268 register struct mbuf *m; 269 register struct ether_header *eh; 270 register struct ether_arp *ea; 271 struct sockaddr sa; 272 273 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 274 return; 275 m->m_len = sizeof(*ea); 276 m->m_pkthdr.len = sizeof(*ea); 277 MH_ALIGN(m, sizeof(*ea)); 278 ea = mtod(m, struct ether_arp *); 279 eh = (struct ether_header *)sa.sa_data; 280 bzero((caddr_t)ea, sizeof (*ea)); 281 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 282 eh->ether_type = ETHERTYPE_ARP; /* if_output will swap */ 283 ea->arp_hrd = htons(ARPHRD_ETHER); 284 ea->arp_pro = htons(ETHERTYPE_IP); 285 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 286 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 287 ea->arp_op = htons(ARPOP_REQUEST); 288 (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 289 (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 290 (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 291 sa.sa_family = AF_UNSPEC; 292 sa.sa_len = sizeof(sa); 293 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 294} 295 296/* 297 * Resolve an IP address into an ethernet address. If success, 298 * desten is filled in. If there is no entry in arptab, 299 * set one up and broadcast a request for the IP address. 300 * Hold onto this mbuf and resend it once the address 301 * is finally resolved. A return value of 1 indicates 302 * that desten has been filled in and the packet should be sent 303 * normally; a 0 return indicates that the packet has been 304 * taken over here, either now or for later transmission. 305 */ 306int 307arpresolve(ac, rt, m, dst, desten, rt0) 308 register struct arpcom *ac; 309 register struct rtentry *rt; 310 struct mbuf *m; 311 register struct sockaddr *dst; 312 register u_char *desten; 313 struct rtentry *rt0; 314{ 315 register struct llinfo_arp *la; 316 struct sockaddr_dl *sdl; 317 318 if (m->m_flags & M_BCAST) { /* broadcast */ 319 (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 320 return (1); 321 } 322 if (m->m_flags & M_MCAST) { /* multicast */ 323 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 324 return(1); 325 } 326 if (rt) 327 la = (struct llinfo_arp *)rt->rt_llinfo; 328 else { 329 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 330 if (la) 331 rt = la->la_rt; 332 } 333 if (la == 0 || rt == 0) { 334 log(LOG_DEBUG, "arpresolve: can't allocate llinfo\n"); 335 m_freem(m); 336 return (0); 337 } 338 sdl = SDL(rt->rt_gateway); 339 /* 340 * Check the address family and length is valid, the address 341 * is resolved; otherwise, try to resolve. 342 */ 343 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 344 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 345 (void)memcpy(desten, LLADDR(sdl), sdl->sdl_alen); 346 return 1; 347 } 348 /* 349 * There is an arptab entry, but no ethernet address 350 * response yet. Replace the held mbuf with this 351 * latest one. 352 */ 353 if (la->la_hold) 354 m_freem(la->la_hold); 355 la->la_hold = m; 356 if (rt->rt_expire) { 357 rt->rt_flags &= ~RTF_REJECT; 358 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 359 rt->rt_expire = time.tv_sec; 360 if (la->la_asked++ < arp_maxtries) 361 arpwhohas(ac, &(SIN(dst)->sin_addr)); 362 else { 363 rt->rt_flags |= RTF_REJECT; 364 rt->rt_expire += arpt_down; 365 la->la_asked = 0; 366 } 367 368 } 369 } 370 return (0); 371} 372 373/* 374 * Common length and type checks are done here, 375 * then the protocol-specific routine is called. 376 */ 377static void 378arpintr(void) 379{ 380 register struct mbuf *m; 381 register struct arphdr *ar; 382 int s; 383 384 while (arpintrq.ifq_head) { 385 s = splimp(); 386 IF_DEQUEUE(&arpintrq, m); 387 splx(s); 388 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 389 panic("arpintr"); 390 if (m->m_len >= sizeof(struct arphdr) && 391 (ar = mtod(m, struct arphdr *)) && 392 ntohs(ar->ar_hrd) == ARPHRD_ETHER && 393 m->m_len >= 394 sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln) 395 396 switch (ntohs(ar->ar_pro)) { 397 398 case ETHERTYPE_IP: 399 in_arpinput(m); 400 continue; 401 } 402 m_freem(m); 403 } 404} 405 406NETISR_SET(NETISR_ARP, arpintr); 407 408/* 409 * ARP for Internet protocols on 10 Mb/s Ethernet. 410 * Algorithm is that given in RFC 826. 411 * In addition, a sanity check is performed on the sender 412 * protocol address, to catch impersonators. 413 * We no longer handle negotiations for use of trailer protocol: 414 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 415 * along with IP replies if we wanted trailers sent to us, 416 * and also sent them in response to IP replies. 417 * This allowed either end to announce the desire to receive 418 * trailer packets. 419 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 420 * but formerly didn't normally send requests. 421 */ 422static void 423in_arpinput(m) 424 struct mbuf *m; 425{ 426 register struct ether_arp *ea; 427 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 428 struct ether_header *eh; 429 register struct llinfo_arp *la = 0; 430 register struct rtentry *rt; 431 struct in_ifaddr *ia, *maybe_ia = 0; 432 struct sockaddr_dl *sdl; 433 struct sockaddr sa; 434 struct in_addr isaddr, itaddr, myaddr; 435 int op; 436 437 ea = mtod(m, struct ether_arp *); 438 op = ntohs(ea->arp_op); 439 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 440 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 441 for (ia = in_ifaddr; ia; ia = ia->ia_next) 442 if (ia->ia_ifp == &ac->ac_if) { 443 maybe_ia = ia; 444 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 445 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 446 break; 447 } 448 if (maybe_ia == 0) { 449 m_freem(m); 450 return; 451 } 452 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 453 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 454 sizeof (ea->arp_sha))) { 455 m_freem(m); /* it's from me, ignore it. */ 456 return; 457 } 458 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 459 sizeof (ea->arp_sha))) { 460 log(LOG_ERR, 461 "arp: ether address is broadcast for IP address %s!\n", 462 inet_ntoa(isaddr)); 463 m_freem(m); 464 return; 465 } 466 if (isaddr.s_addr == myaddr.s_addr) { 467 log(LOG_ERR, 468 "duplicate IP address %s! sent from ethernet address: %s\n", 469 inet_ntoa(isaddr), ether_sprintf(ea->arp_sha)); 470 itaddr = myaddr; 471 goto reply; 472 } 473 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 474 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 475 if (sdl->sdl_alen && 476 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 477 log(LOG_INFO, "arp info overwritten for %s by %s\n", 478 inet_ntoa(isaddr), ether_sprintf(ea->arp_sha)); 479 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 480 sdl->sdl_alen = sizeof(ea->arp_sha); 481 if (rt->rt_expire) 482 rt->rt_expire = time.tv_sec + arpt_keep; 483 rt->rt_flags &= ~RTF_REJECT; 484 la->la_asked = 0; 485 if (la->la_hold) { 486 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 487 rt_key(rt), rt); 488 la->la_hold = 0; 489 } 490 } 491reply: 492 if (op != ARPOP_REQUEST) { 493 m_freem(m); 494 return; 495 } 496 if (itaddr.s_addr == myaddr.s_addr) { 497 /* I am the target */ 498 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 499 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 500 } else { 501 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 502 if (la == NULL) { 503 struct sockaddr_in sin; 504 505 if (!arp_proxyall) { 506 m_freem(m); 507 return; 508 } 509 510 bzero(&sin, sizeof sin); 511 sin.sin_family = AF_INET; 512 sin.sin_len = sizeof sin; 513 sin.sin_addr = itaddr; 514 515 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 516 if (!rt) { 517 m_freem(m); 518 return; 519 } 520 /* 521 * Don't send proxies for nodes on the same interface 522 * as this one came out of, or we'll get into a fight 523 * over who claims what Ether address. 524 */ 525 if (rt->rt_ifp == &ac->ac_if) { 526 rtfree(rt); 527 m_freem(m); 528 return; 529 } 530 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 531 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 532 rtfree(rt); 533#ifdef DEBUG_PROXY 534 printf("arp: proxying for %s\n", 535 inet_ntoa(itaddr)); 536#endif 537 } else { 538 rt = la->la_rt; 539 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 540 sdl = SDL(rt->rt_gateway); 541 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 542 } 543 } 544 545 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 546 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 547 ea->arp_op = htons(ARPOP_REPLY); 548 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 549 eh = (struct ether_header *)sa.sa_data; 550 (void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); 551 eh->ether_type = ETHERTYPE_ARP; 552 sa.sa_family = AF_UNSPEC; 553 sa.sa_len = sizeof(sa); 554 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 555 return; 556} 557 558/* 559 * Free an arp entry. 560 */ 561static void 562arptfree(la) 563 register struct llinfo_arp *la; 564{ 565 register struct rtentry *rt = la->la_rt; 566 register struct sockaddr_dl *sdl; 567 if (rt == 0) 568 panic("arptfree"); 569 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 570 sdl->sdl_family == AF_LINK) { 571 sdl->sdl_alen = 0; 572 la->la_asked = 0; 573 rt->rt_flags &= ~RTF_REJECT; 574 return; 575 } 576 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 577 0, (struct rtentry **)0); 578} 579/* 580 * Lookup or enter a new address in arptab. 581 */ 582static struct llinfo_arp * 583arplookup(addr, create, proxy) 584 u_long addr; 585 int create, proxy; 586{ 587 register struct rtentry *rt; 588 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 589 const char *why = 0; 590 591 sin.sin_addr.s_addr = addr; 592 sin.sin_other = proxy ? SIN_PROXY : 0; 593 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 594 if (rt == 0) 595 return (0); 596 rt->rt_refcnt--; 597 598 if (rt->rt_flags & RTF_GATEWAY) 599 why = "host is not on local network"; 600 else if ((rt->rt_flags & RTF_LLINFO) == 0) 601 why = "could not allocate llinfo"; 602 else if (rt->rt_gateway->sa_family != AF_LINK) 603 why = "gateway route is not ours"; 604 605 if (why && create) { 606 log(LOG_DEBUG, "arplookup %s failed: %s\n", 607 inet_ntoa(sin.sin_addr), why); 608 return 0; 609 } else if (why) { 610 return 0; 611 } 612 return ((struct llinfo_arp *)rt->rt_llinfo); 613} 614 615void 616arp_ifinit(ac, ifa) 617 struct arpcom *ac; 618 struct ifaddr *ifa; 619{ 620 ac->ac_ipaddr = IA_SIN(ifa)->sin_addr; 621 arpwhohas(ac, &ac->ac_ipaddr); 622 ifa->ifa_rtrequest = arp_rtrequest; 623 ifa->ifa_flags |= RTF_CLONING; 624} 625