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 1.42 1997/12/20 00:07:11 bde Exp $ 35 */ 36 37 /* 38 * Ethernet address resolution protocol. 39 * TODO: 40 * add "inuse/lock" bit (or ref. count) along with valid bit 41 */ 42 43 #include "opt_inet.h" 44 45 #include <sys/param.h> 46 #include <sys/kernel.h> 47 #include <sys/sysctl.h> 48 #include <sys/systm.h> 49 #include <sys/mbuf.h> 50 #include <sys/malloc.h> 51 #include <sys/socket.h> 52 #include <sys/syslog.h> 53 54 #include <net/if.h> 55 #include <net/if_dl.h> 56 #include <net/route.h> 57 #include <net/netisr.h> 58 59 #include <netinet/in.h> 60 #include <netinet/in_var.h> 61 #include <netinet/if_ether.h> 62 63 #define SIN(s) ((struct sockaddr_in *)s) 64 #define SDL(s) ((struct sockaddr_dl *)s) 65 66 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 67 68 /* timer values */ 69 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 70 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 71 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 72 73 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 74 &arpt_prune, 0, ""); 75 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 76 &arpt_keep, 0, ""); 77 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 78 &arpt_down, 0, ""); 79 80 #define rt_expire rt_rmx.rmx_expire 81 82 struct llinfo_arp { 83 LIST_ENTRY(llinfo_arp) la_le; 84 struct rtentry *la_rt; 85 struct mbuf *la_hold; /* last packet until resolved/timeout */ 86 long la_asked; /* last time we QUERIED for this addr */ 87 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 88 }; 89 90 static LIST_HEAD(, llinfo_arp) llinfo_arp; 91 92 struct ifqueue arpintrq = {0, 0, 0, 50}; 93 static int arp_inuse, arp_allocated; 94 95 static int arp_maxtries = 5; 96 static int useloopback = 1; /* use loopback interface for local traffic */ 97 static int arp_proxyall = 0; 98 99 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 100 &arp_maxtries, 0, ""); 101 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 102 &useloopback, 0, ""); 103 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 104 &arp_proxyall, 0, ""); 105 106 static void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 107 static void arprequest __P((struct arpcom *, u_long *, u_long *, u_char *)); 108 static void arpintr __P((void)); 109 static void arptfree __P((struct llinfo_arp *)); 110 static void arptimer __P((void *)); 111 static struct llinfo_arp 112 *arplookup __P((u_long, int, int)); 113 #ifdef INET 114 static void in_arpinput __P((struct mbuf *)); 115 #endif 116 117 /* 118 * Timeout routine. Age arp_tab entries periodically. 119 */ 120 /* ARGSUSED */ 121 static void 122 arptimer(ignored_arg) 123 void *ignored_arg; 124 { 125 int s = splnet(); 126 register struct llinfo_arp *la = llinfo_arp.lh_first; 127 struct llinfo_arp *ola; 128 129 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 130 while ((ola = la) != 0) { 131 register struct rtentry *rt = la->la_rt; 132 la = la->la_le.le_next; 133 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 134 arptfree(ola); /* timer has expired, clear */ 135 } 136 splx(s); 137 } 138 139 /* 140 * Parallel to llc_rtrequest. 141 */ 142 static void 143 arp_rtrequest(req, rt, sa) 144 int req; 145 register struct rtentry *rt; 146 struct sockaddr *sa; 147 { 148 register struct sockaddr *gate = rt->rt_gateway; 149 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 150 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 151 static int arpinit_done; 152 153 if (!arpinit_done) { 154 arpinit_done = 1; 155 LIST_INIT(&llinfo_arp); 156 timeout(arptimer, (caddr_t)0, hz); 157 } 158 if (rt->rt_flags & RTF_GATEWAY) 159 return; 160 switch (req) { 161 162 case RTM_ADD: 163 /* 164 * XXX: If this is a manually added route to interface 165 * such as older version of routed or gated might provide, 166 * restore cloning bit. 167 */ 168 if ((rt->rt_flags & RTF_HOST) == 0 && 169 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 170 rt->rt_flags |= RTF_CLONING; 171 if (rt->rt_flags & RTF_CLONING) { 172 /* 173 * Case 1: This route should come from a route to iface. 174 */ 175 rt_setgate(rt, rt_key(rt), 176 (struct sockaddr *)&null_sdl); 177 gate = rt->rt_gateway; 178 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 179 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 180 rt->rt_expire = time.tv_sec; 181 break; 182 } 183 /* Announce a new entry if requested. */ 184 if (rt->rt_flags & RTF_ANNOUNCE) 185 arprequest((struct arpcom *)rt->rt_ifp, 186 &SIN(rt_key(rt))->sin_addr.s_addr, 187 &SIN(rt_key(rt))->sin_addr.s_addr, 188 (u_char *)LLADDR(SDL(gate))); 189 /*FALLTHROUGH*/ 190 case RTM_RESOLVE: 191 if (gate->sa_family != AF_LINK || 192 gate->sa_len < sizeof(null_sdl)) { 193 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 194 break; 195 } 196 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 197 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 198 if (la != 0) 199 break; /* This happens on a route change */ 200 /* 201 * Case 2: This route may come from cloning, or a manual route 202 * add with a LL address. 203 */ 204 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 205 rt->rt_llinfo = (caddr_t)la; 206 if (la == 0) { 207 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 208 break; 209 } 210 arp_inuse++, arp_allocated++; 211 Bzero(la, sizeof(*la)); 212 la->la_rt = rt; 213 rt->rt_flags |= RTF_LLINFO; 214 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 215 216 #ifdef INET 217 /* 218 * This keeps the multicast addresses from showing up 219 * in `arp -a' listings as unresolved. It's not actually 220 * functional. Then the same for broadcast. 221 */ 222 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 223 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 224 LLADDR(SDL(gate))); 225 SDL(gate)->sdl_alen = 6; 226 rt->rt_expire = 0; 227 } 228 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 229 memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6); 230 SDL(gate)->sdl_alen = 6; 231 rt->rt_expire = 0; 232 } 233 #endif 234 235 if (SIN(rt_key(rt))->sin_addr.s_addr == 236 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 237 /* 238 * This test used to be 239 * if (loif.if_flags & IFF_UP) 240 * It allowed local traffic to be forced 241 * through the hardware by configuring the loopback down. 242 * However, it causes problems during network configuration 243 * for boards that can't receive packets they send. 244 * It is now necessary to clear "useloopback" and remove 245 * the route to force traffic out to the hardware. 246 */ 247 rt->rt_expire = 0; 248 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 249 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 250 if (useloopback) 251 rt->rt_ifp = loif; 252 253 } 254 break; 255 256 case RTM_DELETE: 257 if (la == 0) 258 break; 259 arp_inuse--; 260 LIST_REMOVE(la, la_le); 261 rt->rt_llinfo = 0; 262 rt->rt_flags &= ~RTF_LLINFO; 263 if (la->la_hold) 264 m_freem(la->la_hold); 265 Free((caddr_t)la); 266 } 267 } 268 269 /* 270 * Broadcast an ARP request. Caller specifies: 271 * - arp header source ip address 272 * - arp header target ip address 273 * - arp header source ethernet address 274 */ 275 static void 276 arprequest(ac, sip, tip, enaddr) 277 register struct arpcom *ac; 278 register u_long *sip, *tip; 279 register u_char *enaddr; 280 { 281 register struct mbuf *m; 282 register struct ether_header *eh; 283 register struct ether_arp *ea; 284 struct sockaddr sa; 285 286 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 287 return; 288 m->m_len = sizeof(*ea); 289 m->m_pkthdr.len = sizeof(*ea); 290 MH_ALIGN(m, sizeof(*ea)); 291 ea = mtod(m, struct ether_arp *); 292 eh = (struct ether_header *)sa.sa_data; 293 bzero((caddr_t)ea, sizeof (*ea)); 294 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 295 eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 296 ea->arp_hrd = htons(ARPHRD_ETHER); 297 ea->arp_pro = htons(ETHERTYPE_IP); 298 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 299 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 300 ea->arp_op = htons(ARPOP_REQUEST); 301 (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 302 (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 303 (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 304 sa.sa_family = AF_UNSPEC; 305 sa.sa_len = sizeof(sa); 306 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 307 } 308 309 /* 310 * Resolve an IP address into an ethernet address. If success, 311 * desten is filled in. If there is no entry in arptab, 312 * set one up and broadcast a request for the IP address. 313 * Hold onto this mbuf and resend it once the address 314 * is finally resolved. A return value of 1 indicates 315 * that desten has been filled in and the packet should be sent 316 * normally; a 0 return indicates that the packet has been 317 * taken over here, either now or for later transmission. 318 */ 319 int 320 arpresolve(ac, rt, m, dst, desten, rt0) 321 register struct arpcom *ac; 322 register struct rtentry *rt; 323 struct mbuf *m; 324 register struct sockaddr *dst; 325 register u_char *desten; 326 struct rtentry *rt0; 327 { 328 register struct llinfo_arp *la; 329 struct sockaddr_dl *sdl; 330 331 if (m->m_flags & M_BCAST) { /* broadcast */ 332 (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 333 return (1); 334 } 335 if (m->m_flags & M_MCAST) { /* multicast */ 336 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 337 return(1); 338 } 339 if (rt) 340 la = (struct llinfo_arp *)rt->rt_llinfo; 341 else { 342 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 343 if (la) 344 rt = la->la_rt; 345 } 346 if (la == 0 || rt == 0) { 347 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s\n", 348 inet_ntoa(SIN(dst)->sin_addr)); 349 m_freem(m); 350 return (0); 351 } 352 sdl = SDL(rt->rt_gateway); 353 /* 354 * Check the address family and length is valid, the address 355 * is resolved; otherwise, try to resolve. 356 */ 357 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 358 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 359 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 360 return 1; 361 } 362 /* 363 * There is an arptab entry, but no ethernet address 364 * response yet. Replace the held mbuf with this 365 * latest one. 366 */ 367 if (la->la_hold) 368 m_freem(la->la_hold); 369 la->la_hold = m; 370 if (rt->rt_expire) { 371 rt->rt_flags &= ~RTF_REJECT; 372 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 373 rt->rt_expire = time.tv_sec; 374 if (la->la_asked++ < arp_maxtries) 375 arprequest(ac, 376 &(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr), 377 &(SIN(dst)->sin_addr.s_addr), 378 ac->ac_enaddr); 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 */ 394 static void 395 arpintr() 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 #ifdef INET 416 case ETHERTYPE_IP: 417 in_arpinput(m); 418 continue; 419 #endif 420 } 421 m_freem(m); 422 } 423 } 424 425 NETISR_SET(NETISR_ARP, arpintr); 426 427 428 #ifdef INET 429 /* 430 * ARP for Internet protocols on 10 Mb/s Ethernet. 431 * Algorithm is that given in RFC 826. 432 * In addition, a sanity check is performed on the sender 433 * protocol address, to catch impersonators. 434 * We no longer handle negotiations for use of trailer protocol: 435 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 436 * along with IP replies if we wanted trailers sent to us, 437 * and also sent them in response to IP replies. 438 * This allowed either end to announce the desire to receive 439 * trailer packets. 440 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 441 * but formerly didn't normally send requests. 442 */ 443 static void 444 in_arpinput(m) 445 struct mbuf *m; 446 { 447 register struct ether_arp *ea; 448 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 449 struct ether_header *eh; 450 register struct llinfo_arp *la = 0; 451 register struct rtentry *rt; 452 struct in_ifaddr *ia, *maybe_ia = 0; 453 struct sockaddr_dl *sdl; 454 struct sockaddr sa; 455 struct in_addr isaddr, itaddr, myaddr; 456 int op; 457 458 ea = mtod(m, struct ether_arp *); 459 op = ntohs(ea->arp_op); 460 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 461 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 462 for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) 463 if (ia->ia_ifp == &ac->ac_if) { 464 maybe_ia = ia; 465 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 466 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 467 break; 468 } 469 if (maybe_ia == 0) { 470 m_freem(m); 471 return; 472 } 473 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 474 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 475 sizeof (ea->arp_sha))) { 476 m_freem(m); /* it's from me, ignore it. */ 477 return; 478 } 479 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 480 sizeof (ea->arp_sha))) { 481 log(LOG_ERR, 482 "arp: ether address is broadcast for IP address %s!\n", 483 inet_ntoa(isaddr)); 484 m_freem(m); 485 return; 486 } 487 if (isaddr.s_addr == myaddr.s_addr) { 488 log(LOG_ERR, 489 "arp: %6D is using my IP address %s!\n", 490 ea->arp_sha, ":", inet_ntoa(isaddr)); 491 itaddr = myaddr; 492 goto reply; 493 } 494 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 495 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 496 if (sdl->sdl_alen && 497 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 498 log(LOG_INFO, "arp: %s moved from %6D to %6D\n", 499 inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":", 500 ea->arp_sha, ":"); 501 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 502 sdl->sdl_alen = sizeof(ea->arp_sha); 503 if (rt->rt_expire) 504 rt->rt_expire = time.tv_sec + arpt_keep; 505 rt->rt_flags &= ~RTF_REJECT; 506 la->la_asked = 0; 507 if (la->la_hold) { 508 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 509 rt_key(rt), rt); 510 la->la_hold = 0; 511 } 512 } 513 reply: 514 if (op != ARPOP_REQUEST) { 515 m_freem(m); 516 return; 517 } 518 if (itaddr.s_addr == myaddr.s_addr) { 519 /* I am the target */ 520 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 521 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 522 } else { 523 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 524 if (la == NULL) { 525 struct sockaddr_in sin; 526 527 if (!arp_proxyall) { 528 m_freem(m); 529 return; 530 } 531 532 bzero(&sin, sizeof sin); 533 sin.sin_family = AF_INET; 534 sin.sin_len = sizeof sin; 535 sin.sin_addr = itaddr; 536 537 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 538 if (!rt) { 539 m_freem(m); 540 return; 541 } 542 /* 543 * Don't send proxies for nodes on the same interface 544 * as this one came out of, or we'll get into a fight 545 * over who claims what Ether address. 546 */ 547 if (rt->rt_ifp == &ac->ac_if) { 548 rtfree(rt); 549 m_freem(m); 550 return; 551 } 552 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 553 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 554 rtfree(rt); 555 #ifdef DEBUG_PROXY 556 printf("arp: proxying for %s\n", 557 inet_ntoa(itaddr)); 558 #endif 559 } else { 560 rt = la->la_rt; 561 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 562 sdl = SDL(rt->rt_gateway); 563 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 564 } 565 } 566 567 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 568 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 569 ea->arp_op = htons(ARPOP_REPLY); 570 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 571 eh = (struct ether_header *)sa.sa_data; 572 (void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); 573 eh->ether_type = htons(ETHERTYPE_ARP); 574 sa.sa_family = AF_UNSPEC; 575 sa.sa_len = sizeof(sa); 576 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 577 return; 578 } 579 #endif 580 581 /* 582 * Free an arp entry. 583 */ 584 static void 585 arptfree(la) 586 register struct llinfo_arp *la; 587 { 588 register struct rtentry *rt = la->la_rt; 589 register struct sockaddr_dl *sdl; 590 if (rt == 0) 591 panic("arptfree"); 592 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 593 sdl->sdl_family == AF_LINK) { 594 sdl->sdl_alen = 0; 595 la->la_asked = 0; 596 rt->rt_flags &= ~RTF_REJECT; 597 return; 598 } 599 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 600 0, (struct rtentry **)0); 601 } 602 /* 603 * Lookup or enter a new address in arptab. 604 */ 605 static struct llinfo_arp * 606 arplookup(addr, create, proxy) 607 u_long addr; 608 int create, proxy; 609 { 610 register struct rtentry *rt; 611 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 612 const char *why = 0; 613 614 sin.sin_addr.s_addr = addr; 615 sin.sin_other = proxy ? SIN_PROXY : 0; 616 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 617 if (rt == 0) 618 return (0); 619 rt->rt_refcnt--; 620 621 if (rt->rt_flags & RTF_GATEWAY) 622 why = "host is not on local network"; 623 else if ((rt->rt_flags & RTF_LLINFO) == 0) 624 why = "could not allocate llinfo"; 625 else if (rt->rt_gateway->sa_family != AF_LINK) 626 why = "gateway route is not ours"; 627 628 if (why && create) { 629 log(LOG_DEBUG, "arplookup %s failed: %s\n", 630 inet_ntoa(sin.sin_addr), why); 631 return 0; 632 } else if (why) { 633 return 0; 634 } 635 return ((struct llinfo_arp *)rt->rt_llinfo); 636 } 637 638 void 639 arp_ifinit(ac, ifa) 640 struct arpcom *ac; 641 struct ifaddr *ifa; 642 { 643 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 644 arprequest(ac, &(IA_SIN(ifa)->sin_addr.s_addr), 645 &(IA_SIN(ifa)->sin_addr.s_addr), ac->ac_enaddr); 646 ifa->ifa_rtrequest = arp_rtrequest; 647 ifa->ifa_flags |= RTF_CLONING; 648 } 649