if_ether.c revision 14163
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 1.27 1996/02/05 18:04:30 wollman 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_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 65 66/* timer values */ 67static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 68static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 69static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 70 71SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 72 &arpt_prune, 0, ""); 73SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 74 &arpt_keep, 0, ""); 75SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 76 &arpt_down, 0, ""); 77 78#define rt_expire rt_rmx.rmx_expire 79 80struct llinfo_arp { 81 LIST_ENTRY(llinfo_arp) la_le; 82 struct rtentry *la_rt; 83 struct mbuf *la_hold; /* last packet until resolved/timeout */ 84 long la_asked; /* last time we QUERIED for this addr */ 85#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 86}; 87 88static LIST_HEAD(, llinfo_arp) llinfo_arp; 89 90struct ifqueue arpintrq = {0, 0, 0, 50}; 91static int arp_inuse, arp_allocated; 92 93static int arp_maxtries = 5; 94static int useloopback = 1; /* use loopback interface for local traffic */ 95static int arp_proxyall = 0; 96 97SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 98 &arp_maxtries, 0, ""); 99SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 100 &useloopback, 0, ""); 101SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 102 &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); 212 213 /* 214 * This keeps the multicast addresses from showing up 215 * in `arp -a' listings as unresolved. It's not actually 216 * functional. Then the same for broadcast. 217 */ 218 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 219 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 220 LLADDR(SDL(gate))); 221 SDL(gate)->sdl_alen = 6; 222 } 223 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 224 memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6); 225 SDL(gate)->sdl_alen = 6; 226 } 227 228 if (SIN(rt_key(rt))->sin_addr.s_addr == 229 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 230 /* 231 * This test used to be 232 * if (loif.if_flags & IFF_UP) 233 * It allowed local traffic to be forced 234 * through the hardware by configuring the loopback down. 235 * However, it causes problems during network configuration 236 * for boards that can't receive packets they send. 237 * It is now necessary to clear "useloopback" and remove 238 * the route to force traffic out to the hardware. 239 */ 240 rt->rt_expire = 0; 241 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 242 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 243 if (useloopback) 244 rt->rt_ifp = loif; 245 246 } 247 break; 248 249 case RTM_DELETE: 250 if (la == 0) 251 break; 252 arp_inuse--; 253 LIST_REMOVE(la, la_le); 254 rt->rt_llinfo = 0; 255 rt->rt_flags &= ~RTF_LLINFO; 256 if (la->la_hold) 257 m_freem(la->la_hold); 258 Free((caddr_t)la); 259 } 260} 261/* 262 * Broadcast an ARP packet, asking who has addr on interface ac. 263 */ 264static void 265arpwhohas(ac, addr) 266 struct arpcom *ac; 267 struct in_addr *addr; 268{ 269 arprequest(ac, &ac->ac_ipaddr.s_addr, &addr->s_addr, ac->ac_enaddr); 270} 271 272/* 273 * Broadcast an ARP request. Caller specifies: 274 * - arp header source ip address 275 * - arp header target ip address 276 * - arp header source ethernet address 277 */ 278static void 279arprequest(ac, sip, tip, enaddr) 280 register struct arpcom *ac; 281 register u_long *sip, *tip; 282 register u_char *enaddr; 283{ 284 register struct mbuf *m; 285 register struct ether_header *eh; 286 register struct ether_arp *ea; 287 struct sockaddr sa; 288 289 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 290 return; 291 m->m_len = sizeof(*ea); 292 m->m_pkthdr.len = sizeof(*ea); 293 MH_ALIGN(m, sizeof(*ea)); 294 ea = mtod(m, struct ether_arp *); 295 eh = (struct ether_header *)sa.sa_data; 296 bzero((caddr_t)ea, sizeof (*ea)); 297 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 298 eh->ether_type = ETHERTYPE_ARP; /* if_output will swap */ 299 ea->arp_hrd = htons(ARPHRD_ETHER); 300 ea->arp_pro = htons(ETHERTYPE_IP); 301 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 302 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 303 ea->arp_op = htons(ARPOP_REQUEST); 304 (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 305 (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 306 (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 307 sa.sa_family = AF_UNSPEC; 308 sa.sa_len = sizeof(sa); 309 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 310} 311 312/* 313 * Resolve an IP address into an ethernet address. If success, 314 * desten is filled in. If there is no entry in arptab, 315 * set one up and broadcast a request for the IP address. 316 * Hold onto this mbuf and resend it once the address 317 * is finally resolved. A return value of 1 indicates 318 * that desten has been filled in and the packet should be sent 319 * normally; a 0 return indicates that the packet has been 320 * taken over here, either now or for later transmission. 321 */ 322int 323arpresolve(ac, rt, m, dst, desten, rt0) 324 register struct arpcom *ac; 325 register struct rtentry *rt; 326 struct mbuf *m; 327 register struct sockaddr *dst; 328 register u_char *desten; 329 struct rtentry *rt0; 330{ 331 register struct llinfo_arp *la; 332 struct sockaddr_dl *sdl; 333 334 if (m->m_flags & M_BCAST) { /* broadcast */ 335 (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 336 return (1); 337 } 338 if (m->m_flags & M_MCAST) { /* multicast */ 339 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 340 return(1); 341 } 342 if (rt) 343 la = (struct llinfo_arp *)rt->rt_llinfo; 344 else { 345 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 346 if (la) 347 rt = la->la_rt; 348 } 349 if (la == 0 || rt == 0) { 350 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s\n", 351 inet_ntoa(SIN(dst)->sin_addr)); 352 m_freem(m); 353 return (0); 354 } 355 sdl = SDL(rt->rt_gateway); 356 /* 357 * Check the address family and length is valid, the address 358 * is resolved; otherwise, try to resolve. 359 */ 360 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 361 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 362 (void)memcpy(desten, LLADDR(sdl), sdl->sdl_alen); 363 return 1; 364 } 365 /* 366 * There is an arptab entry, but no ethernet address 367 * response yet. Replace the held mbuf with this 368 * latest one. 369 */ 370 if (la->la_hold) 371 m_freem(la->la_hold); 372 la->la_hold = m; 373 if (rt->rt_expire) { 374 rt->rt_flags &= ~RTF_REJECT; 375 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 376 rt->rt_expire = time.tv_sec; 377 if (la->la_asked++ < arp_maxtries) 378 arpwhohas(ac, &(SIN(dst)->sin_addr)); 379 else { 380 rt->rt_flags |= RTF_REJECT; 381 rt->rt_expire += arpt_down; 382 la->la_asked = 0; 383 } 384 385 } 386 } 387 return (0); 388} 389 390/* 391 * Common length and type checks are done here, 392 * then the protocol-specific routine is called. 393 */ 394static void 395arpintr(void) 396{ 397 register struct mbuf *m; 398 register struct arphdr *ar; 399 int s; 400 401 while (arpintrq.ifq_head) { 402 s = splimp(); 403 IF_DEQUEUE(&arpintrq, m); 404 splx(s); 405 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 406 panic("arpintr"); 407 if (m->m_len >= sizeof(struct arphdr) && 408 (ar = mtod(m, struct arphdr *)) && 409 ntohs(ar->ar_hrd) == ARPHRD_ETHER && 410 m->m_len >= 411 sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln) 412 413 switch (ntohs(ar->ar_pro)) { 414 415 case ETHERTYPE_IP: 416 in_arpinput(m); 417 continue; 418 } 419 m_freem(m); 420 } 421} 422 423NETISR_SET(NETISR_ARP, arpintr); 424 425/* 426 * ARP for Internet protocols on 10 Mb/s Ethernet. 427 * Algorithm is that given in RFC 826. 428 * In addition, a sanity check is performed on the sender 429 * protocol address, to catch impersonators. 430 * We no longer handle negotiations for use of trailer protocol: 431 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 432 * along with IP replies if we wanted trailers sent to us, 433 * and also sent them in response to IP replies. 434 * This allowed either end to announce the desire to receive 435 * trailer packets. 436 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 437 * but formerly didn't normally send requests. 438 */ 439static void 440in_arpinput(m) 441 struct mbuf *m; 442{ 443 register struct ether_arp *ea; 444 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 445 struct ether_header *eh; 446 register struct llinfo_arp *la = 0; 447 register struct rtentry *rt; 448 struct in_ifaddr *ia, *maybe_ia = 0; 449 struct sockaddr_dl *sdl; 450 struct sockaddr sa; 451 struct in_addr isaddr, itaddr, myaddr; 452 int op; 453 454 ea = mtod(m, struct ether_arp *); 455 op = ntohs(ea->arp_op); 456 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 457 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 458 for (ia = in_ifaddr; ia; ia = ia->ia_next) 459 if (ia->ia_ifp == &ac->ac_if) { 460 maybe_ia = ia; 461 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 462 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 463 break; 464 } 465 if (maybe_ia == 0) { 466 m_freem(m); 467 return; 468 } 469 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 470 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 471 sizeof (ea->arp_sha))) { 472 m_freem(m); /* it's from me, ignore it. */ 473 return; 474 } 475 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 476 sizeof (ea->arp_sha))) { 477 log(LOG_ERR, 478 "arp: ether address is broadcast for IP address %s!\n", 479 inet_ntoa(isaddr)); 480 m_freem(m); 481 return; 482 } 483 if (isaddr.s_addr == myaddr.s_addr) { 484 log(LOG_ERR, 485 "duplicate IP address %s! sent from ethernet address: %6D\n", 486 inet_ntoa(isaddr), ea->arp_sha, ":"); 487 itaddr = myaddr; 488 goto reply; 489 } 490 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 491 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 492 if (sdl->sdl_alen && 493 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 494 log(LOG_INFO, "arp info overwritten for %s by %6D\n", 495 inet_ntoa(isaddr), ea->arp_sha, ":"); 496 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 497 sdl->sdl_alen = sizeof(ea->arp_sha); 498 if (rt->rt_expire) 499 rt->rt_expire = time.tv_sec + arpt_keep; 500 rt->rt_flags &= ~RTF_REJECT; 501 la->la_asked = 0; 502 if (la->la_hold) { 503 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 504 rt_key(rt), rt); 505 la->la_hold = 0; 506 } 507 } 508reply: 509 if (op != ARPOP_REQUEST) { 510 m_freem(m); 511 return; 512 } 513 if (itaddr.s_addr == myaddr.s_addr) { 514 /* I am the target */ 515 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 516 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 517 } else { 518 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 519 if (la == NULL) { 520 struct sockaddr_in sin; 521 522 if (!arp_proxyall) { 523 m_freem(m); 524 return; 525 } 526 527 bzero(&sin, sizeof sin); 528 sin.sin_family = AF_INET; 529 sin.sin_len = sizeof sin; 530 sin.sin_addr = itaddr; 531 532 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 533 if (!rt) { 534 m_freem(m); 535 return; 536 } 537 /* 538 * Don't send proxies for nodes on the same interface 539 * as this one came out of, or we'll get into a fight 540 * over who claims what Ether address. 541 */ 542 if (rt->rt_ifp == &ac->ac_if) { 543 rtfree(rt); 544 m_freem(m); 545 return; 546 } 547 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 548 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 549 rtfree(rt); 550#ifdef DEBUG_PROXY 551 printf("arp: proxying for %s\n", 552 inet_ntoa(itaddr)); 553#endif 554 } else { 555 rt = la->la_rt; 556 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 557 sdl = SDL(rt->rt_gateway); 558 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 559 } 560 } 561 562 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 563 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 564 ea->arp_op = htons(ARPOP_REPLY); 565 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 566 eh = (struct ether_header *)sa.sa_data; 567 (void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); 568 eh->ether_type = ETHERTYPE_ARP; 569 sa.sa_family = AF_UNSPEC; 570 sa.sa_len = sizeof(sa); 571 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 572 return; 573} 574 575/* 576 * Free an arp entry. 577 */ 578static void 579arptfree(la) 580 register struct llinfo_arp *la; 581{ 582 register struct rtentry *rt = la->la_rt; 583 register struct sockaddr_dl *sdl; 584 if (rt == 0) 585 panic("arptfree"); 586 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 587 sdl->sdl_family == AF_LINK) { 588 sdl->sdl_alen = 0; 589 la->la_asked = 0; 590 rt->rt_flags &= ~RTF_REJECT; 591 return; 592 } 593 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 594 0, (struct rtentry **)0); 595} 596/* 597 * Lookup or enter a new address in arptab. 598 */ 599static struct llinfo_arp * 600arplookup(addr, create, proxy) 601 u_long addr; 602 int create, proxy; 603{ 604 register struct rtentry *rt; 605 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 606 const char *why = 0; 607 608 sin.sin_addr.s_addr = addr; 609 sin.sin_other = proxy ? SIN_PROXY : 0; 610 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 611 if (rt == 0) 612 return (0); 613 rt->rt_refcnt--; 614 615 if (rt->rt_flags & RTF_GATEWAY) 616 why = "host is not on local network"; 617 else if ((rt->rt_flags & RTF_LLINFO) == 0) 618 why = "could not allocate llinfo"; 619 else if (rt->rt_gateway->sa_family != AF_LINK) 620 why = "gateway route is not ours"; 621 622 if (why && create) { 623 log(LOG_DEBUG, "arplookup %s failed: %s\n", 624 inet_ntoa(sin.sin_addr), why); 625 return 0; 626 } else if (why) { 627 return 0; 628 } 629 return ((struct llinfo_arp *)rt->rt_llinfo); 630} 631 632void 633arp_ifinit(ac, ifa) 634 struct arpcom *ac; 635 struct ifaddr *ifa; 636{ 637 ac->ac_ipaddr = IA_SIN(ifa)->sin_addr; 638 arpwhohas(ac, &ac->ac_ipaddr); 639 ifa->ifa_rtrequest = arp_rtrequest; 640 ifa->ifa_flags |= RTF_CLONING; 641} 642